Ourstudy reveals the clean deamination of terminal amine groups on theparticle surfaces by NO, exemplifying a unique surface passivationstrategy for COFs. We further describe the formation of a NONOatelinkage by the reaction of NO with an amine-linked COF, which showscontrolled release of NO under physiological conditions. NONOate-COFsthus show promise as tunable NO delivery platforms for bioregulatoryNO release in biomedical applications.Covalent organic frameworks (COFs) have emerged as versatileplatformsfor the separation and storage of hazardous gases. Simultaneously,the synthetic toolbox to tackle the “COF trilemma” hasbeen diversified to include topochemical linkage transformations andpost-synthetic stabilization strategies. Herein, we converge thesethemes and reveal the unique potential of nitric oxide (NO) as a newreagent for the scalable gas-phase transformation of COFs. Using physisorptionand solid-state nuclear magnetic resonance spectroscopy on  Especially early introducedand well-established linkages like boronic esters or imine bonds sufferfrom instability against harsher chemical conditions.2 andCO2. By targeted 15N enrichment at the crucialCOF linkages, we investigate and identify chemical modifications inthe COFs’ frameworks induced by NO. These chemical modifications,including a novel type of linkage, are evaluated for their potentialapplications in COF chemistry and biomedical research.In this work, we determine the stability of four differentCOFlinkages—imine, amine, thiazole, and imide—against NOexposure and examine their suitability for NO separation applicationsby calculating their specific selectivity against N15N-enriched frameworks, namely,TTI-COF, rTTI-COF, TTT-COF, and TT-Imide-COFtrianiline-15N linker  spectroscopy and thus allows a detailed analysis of the respectivelinkages. This is essential since we expect these nitrogen sites tobe the most reactive groups toward NO and therefore to constitutethe most interesting moieties in the COFs during this study.To study the effect of NO onCOFs, we synthesized four mide-COF1,33,37−3TT-15NH2,1. The is15N-enriched COFs were performed starting at 298 K. In all cases, aninitial high but only partially reversible adsorption capacity wasfound within the first adsorption cycle. In this first measurement,COF-dependent uptakes between 1.5 and 6 mmol g–1 NO were observed. In addition, a steep adsorption slope below 2kPa for TT-Imide-COF and TTI-COF (S29), around30 kPa for TTT-COF , and around90 kPa for rTTI-COF was found . The steep uptake within the first cycle at different pressurepoints for each COF indicates differing mechanisms for the irreversiblechemisorption of NO. Thus, in each case, the hysteresis does not closeto the initial point during the first measurement. Multiple adsorptionand desorption cycles at 298 K show a strong decrease in NO uptakeafter the first cycle toward a fraction of the initial uptake. Thistrend of an initial high and irreversible NO uptake and its strongdecline in further cycles indicates a chemisorption process of NOon the frameworks, consistent with a progressive quenching of thereactive sites.NO sorption measurements on Figures S30, S32, S34, and S35). To ensure reproducible NO physisorption dataat different temperatures, all COFs were cycled seven times to ensurestabilization of the systems before measurements at 273, 288, and298 K were performed (S36). In contrast to theinitial NO sorption cycles, subsequent measurements show fully reversibleisotherms for all four COFs, indicating a saturation of the systems.Further, they reveal an unusual hysteresis due to delayed NO desorptionvisible for all temperatures and COFs.For all frameworks, the decline in the irreversibleuptake of NOtoward the second cycle is the most prominent, while the followingsorption cycles show only a small decrease, which stabilizes afterapproximately three cycles  and specific pore volume (VP) decrease for the imine-COF (SBET =1491 m2 g–1 (VP = 0.917) to less than a third for the post-NO imine-COF with SBET = 475 m2 g–1 (VP = 0.376). The amine-COF rTTI-COF(SBET = 1428 m2 g–1 (VP = 0.778) becomes non-porous afterNO exposure with SBET = 32 m2 g–1 (VP = 0.071 cm3 g–1). For TTT-COF and TT-imide-COF (SBET (2 g–1 (VP = 0.778 cm3 g–1) to 1416 m2 g–1 (VP = 0.750cm3 g–1) and from 1190 m2 g–1 (VP = 0.802 cm3 g–1) to 1102 m2 g–1 (VP = 0.744 cm3 g–1), respectively. For the latter, the Fourier transform infrared (FT-IR)spectra before and after NO exposure show no difference . However, TTI-COF-NO displays a new band at 1699 cm–1, atypical range for an aldehyde HC=O vibration, while otherwiseremaining unchanged . The spectrumof rTTI-COF-NO shows significant changes comparedto pristine rTTI-COF, the most prominent is the appearance of threedistinct bands at 1700, 1084, and 916 cm–1 . We also observed a color change ofthe sample after NO exposure. UV–vis measurements reveal slightlyaltered absorption spectra for the post-NO COFs . The most obvious color changes wereperceived for TTI-COF and rTTI-COF– both changing from yellowto brownish color. This analysis reveals that the thiazole and imidelinkages are largely inert against NO exposure since the structuralintegrity and porosity of the respective COFs remain unaffected. Incontrast, the imine and amine linkages seem to react to a varyingdegree with the gas, indicated by changes in the FT-IR spectra, resultingin a loss of structural integrity and porosity.Powder X-ray diffraction (PXRD) analysis of the samples revealsthat TTI-COF-morphous2d,e. Themine-COF 2h from SrTTI-COF2i with imide-COF 2g, f no OF . For the selectivity calculations, we chose a 15/85 gasmixture for CO2/N2, as commonly found in theliterature,41 and a 3/97 gas mixture forNO/N2, due to the low abundance of NO in exhaust gas mixtures.42 We calculated the IAST selectivities of CO2 over nitrogen for TT-Imide-COF-NO and TTT-COF-NO as 9.22 and 6.44, respectively. The IAST selectivityof NO over nitrogen were calculated to be 5.55 for the TT-Imide-COF-NO and 3.95 for TTT-COF-NO. Furthermore,the pressure-dependent selectivity of a binary CO2/NO (50/50)gas mixture was calculated . Overall, our results show that imide- and thiazole-linked COFsexhibit remarkable resistance to NO gas and are promising platformsfor NO gas capture or separation. Moreover, these systems show significantIAST selectivity of NO uptake over N2.Narrowing downsuitable COF linkages for NO adsorption and separationapplications to thiazole and imide functionalities, we further investigatedthe physisorption performance and calculated the selectivity for NOcompared to that for carbon dioxide by applying the ideal adsorptionsolution theory (IAST). Using the post-NO CO13C and 15N CP-MAS ssNMRexperiments. Utilizing the high sensitivity of our 15N-enrichedCOFs, we were able to capture even less-sensitive species like thethiazole nitrogen and minor framework defects, as is discussed inthe following.Next, we turn our attentionto the imine and amine linkages that are more susceptible to NO exposure.To deconvolute the irreversible chemisorption phenomenon during thefirst NO adsorption cycles and to gain insights into possible reactionsinvolved, we performed NO shows no visible changes in its 13C and 15N spectra compared to the spectrum of the pristine TTT-COF, reactions of NO with remaining oligomer impurities, sulfur and/orremaining imine bonds, as observed for TTI-COF (infra vide), are plausible.As one of the NO resistant frameworks, TTT-COF- TTT-COF3a. Inter13C spectrum of TT-Imide-COF-NO resembles the spectrum of the pristine COF . Uponexposure to NO, the signal at −322 ppm, assigned to terminalamine groups, vanished completely, giving the first direct indicationfor a chemical reaction of the framework with the adsorbate. Furthermore,the relative intensity of the amide at −254 ppm is loweredcompared to that of the imide at −207 ppm after NO treatment.Lacking any new signals, we suspect a clean conversion of the aminesby NO, passivating the crystallite surface edges, according to a proposeddenitrogenation radical reaction mechanism depicted in 43The tine COF 3b, top. ectively S11. Upon2O3 impurities in the NO gas, cleaving the diazoniummoiety as dinitrogen and nitrous acid. The resulting phenyl radicalis subsequently quenched by exposure to the nitroxyl released in thefirst step or any other proton-bearing volatile compound, like H2O. Due to the deamination of the enriched 15N,the amine peak disappears and no new signal is visible. We envisionthat this interaction between the free amine groups and the NO gascould be used as a rational surface passivation strategy to purposefullyremove the remaining and potentially reactive amine sites. Clearingthe COF’s surface from terminal amines could be of particularinterest when their chemical reactivity or electronic properties hinderor alter the targeted properties of the framework ,especially when exposed at the crystal surface.First, a diazonium salt is formed in the reactionof the free aminewith NO. This salt further reacts with catalytic amounts of N44A reaction withthe remaining amic acid intermediates remains uncertain.While a slight decline in the relative intensity compared to thatof the imide signal is observed, only a single case of a reactionof NO with primary amides (under strongly basic conditions) has beenreported in the literature, making at least a quantitative reactionunlikely in this case.13C CP-MAS NMR spectrum after NO exposure and a new signalat 191 ppm appears , a species that is also observed duringNO adsorption in amine-functionalized MOFs and is formed by the additionof 2 equiv of NO to the amine linkage of rTTI-COF at 95 kPa NO pressure. The complete disappearance of the 15N-amine indicates full conversion of the amine into the NONOate linkage.Introducing such polar, bulky NONOate groups adds both steric andelectrostatic repulsion between the layers, thus forcing the layersto distort and shift, resulting in the observed loss of long-rangeorder, layer integrity, and porosity. Besides this drawback, the describedsimple gas phase modification of amine-linked COFs by NO introducingNONOate groups displays exciting new possibilities for the designof polymers and COFs bearing novel linkages and functionalities.rTTI-COF-spectrum 5a, top. spectrum 2e. The 1pressure6a,b.1,2447 NO release under physiological conditions was tested by suspendingrTTI-COF-NO in a pH 7.4 PBS buffer solution at 37°C and monitoring the NO release using a Griess assay.48 The NO release profile of rTTI-COF-NO shows an exponential release behavior with an overall very slowbut steady release of the chemisorbed NO over several days , evidencingthe successful rearrangement of the regenerated amine-linked domainsinto an ordered structure. While the total amount per gram of NO deliveredby the COF is significantly lower than that of the NO chemisorbedin recently published MOFs or polymers,49 they are well in the concentration range of physiologicalprocesses.50 In addition, the controlled releaseof NO over such long periods (i.e. multiple days to weeks) sets rTTI-COF-NO apart from the typical rapid release over seconds tohours observed for other NONOate derivatives and suggests that NONOateCOFs could be promising candidates for wound healing or related applicationswhere a slow NO release is key.50 Unlike MOFs, COFs alsodo not contain heavy metals that can prevent their use in pharmaceuticals.Further, we presume that the origin of this moderate but gradual releaseis due to the limited diffusion of water into and NO out of the disorderedand non-porous but flexible framework. We also observed a minor recoveryof crystallinity, which we attribute to the recovery of the originalamine linkage. Due to the small amounts of NO released during therelease experiment, most of the framework remained as the NONOate-linkedCOF. The diffusion of water into the framework is crucial to protonatethe NONOate functional groups and trigger the NO release. Hence, controlover the crystallinity during linkage transformation may be used tocontrol the rate and amount of NO released by NONOate-COFs. Crystallinityand therefore enhanced accessibility of the NONOate functional groupsin the COF pores could be achieved by implementing readily availablestrategies to direct and lock the layer stacking, or by using 3D COFs.54Along these lines, implementing NONOatefunctional groups hold great promise toward COFs as NO releasing deliveryplatforms for bioregulatory NO release in therapeutic or medicinalchemistry applications 6a.5,46,4ral days 6c. An inTaken together, our NMR analysis explains the different linkagestabilities and transformations and rationalizes the observed initialirreversible adsorption behavior, which is largely due to the chemicalreaction of NO with terminal amine groups or linkages of the frameworks.15N-enriched version ofthe commonly used TT-amine linker, which was successfully used toprepare multiple COFs with varying linkage chemistries—imine,amine, thiazole, and imide. The 15N-enriched linkage archetypeswere then used as chemical probes to verify the existence of previouslypostulated terminal groups and reaction intermediates during linkageformation and modification. We demonstrated that all frameworks withunreacted terminal amine sites can be quantitatively passivated withNO by a denitrogenation reaction, leading to a clean surface defunctionalizationof the frameworks. In addition, we could show that the reactivityof the different linkages toward NO is distinctly different: whileimide and thiazole-linked COFs were found to be largely unreactivetoward NO, imine and amine-linked COFs undergo local (imine) and global(amine) linkage conversions, leading to significant changes in thesurface area and framework crystallinity. We have further demonstrateda topochemical modification of amine-linked COFs by NO, forming thenovel NONOate COF linkage by a solid–gas phase reaction atroom temperature. Controlled and extended NO release by this NONOatelinkage was observed under physiological conditions, which opens thedoor to the use of amine-linked COFs as potential platforms for “NOcatch and release” scenarios in biomedical applications. Wehave thus demonstrated that besides being toxic and highly reactive,NO is a versatile reagent for crystal surface and linkage modification,thus greatly expanding the synthetic toolbox of COF chemistry.We have identified NO as a syntheticallyflexible reagent for therational topochemical framework modification in COFs. We have developeda straightforward synthesis of a


Based on SEM, EBSD and TEM characterization, the results showed that the aspect ratio of the α phase decreased with increasing deformation temperatures and decreasing strain rates. At 880 °C/0.001 s−1, the aspect ratio of the α phase was the smallest at 2.05. The proportion of HAGBs decreased with increasing temperatures and strain rates, which was different from the trend of the spheroidization; this indicated that the formation of HAGBs was not necessary for the spheroidization process. Furthermore, the formation of the α/α interface was related to the evolution of dislocations and twin boundaries at high (880 °C) and low temperatures (780 °C), respectively. Moreover, the dependence of lamellar spheroidization on the crystallographic orientation tilt from the compression direction (θ) was clarified: when θ was between 45° and 60°, both the prism <a> slip and basal <a> slip systems were activated together, which was more favorable for spheroidization. This study could provide guidance for titanium alloy process designs and microstructure regulation.The dynamic spheroidization mechanism and its orientation dependence in Ti-6Al-2Mo-2V-1Fe alloys during subtransus hot deformation were studied in this work. For this purpose, hot compression tests were carried out at temperatures of 780–880 °C, with strain rates of 0.001–0.1 s Dual-phase titanium alloys are widely used in the aerospace, navigation and other fields due to its characteristics of low density, high specific strength and excellent plasticity ,2. In orIt is quite difficult to achieve the spheroidization of a lamellar microstructure for titanium alloys from the viewpoint of workability and microstructure regulation. As a result, a large number of studies have been devoted to clarifying the factors affecting dynamic spheroidization and the mechanisms involved. The dynamic spheroidization of lamellar microstructures significantly determines the initial microstructure and processing conditions during the hot deformation process . For exaRecently, the relationship between the spheroidization mechanism and deformation parameters—especially the deformation temperature—has been investigated. For instance, Zherebtsov et al.  reportedIn this study, isothermal compression tests were carried out to clarify the dynamic spheroidization mechanism and its orientation dependence in a Ti-6Al-2Mo-2V-1Fe titanium alloy. The microstructure evolution under various deformation conditions was investigated. The correlation of spheroidization mechanisms and temperatures has also been revealed in detail. The dependence of spheroidization on the crystallographic orientation of the α relative to the compression axis was also clarified. These results could guide the design of hot working and the microstructure regulation of dual-phase titanium alloys.−1, 0.01 s−1 and 0.1 s−1 on a Gleeble-3500 compressor. In order to reduce friction, the top and bottom surfaces of the samples were covered with high-temperature lubricant and tantalum sheets were placed on both ends of the sample and the indenter. Samples were heated to a preset temperature at a heating rate of 10 °C/s and held for 5 min to ensure a uniform temperature before compression. Samples were compressed until the true strain was 0.9, followed by immediate water quenching to retain the high temperature deformation microstructure. In order to elucidate the spheroidization process under high and low temperature conditions, two sets of specimens with true strains of 0.2, 0.5 at 780 °C/0.01 s−1 and 880 °C/0.01 s−1 were also obtained. The specific chemical composition of the experimental material in the present work was 6.2 Al, 2.1 Mo, 2 V and 0.9 Fe, balanced with Ti (wt.%). The as-received alloys were supplied in the form of forged bars that were subjected to the ingot breakdown process in the single β region. The β transus temperature was determined by the metallographic method to be 915 ± 5 °C. The initial microstructure was a typical lamellar microstructure. Cylindrical specimens 10 mm in diameter and 15 mm in height were cut from the billet for hot compression experiments. Uniaxial hot compression experiments were carried out at the deformation temperatures of 780 °C, 830 °C and 880 °C with strain rates of 0.001 s1// radial directions (RD1) and OA2// the compression direction (CD). In order to achieve the surface quality required for the EBSD measurements, the samples were electropolished with a solution of 10% perchloric acid, 30% n-butanol and 60% methanol at −25 °C. In addition, more microscopic features were characterized using a Transmission Electron Microscope (TEM) Tecnai F20 G2 at a voltage of 200 kV. TEM foils were cut from the core of the deformed samples—first mechanically thinned to about 5 μm, and then electropolished using a twin-jet electropolishing device (Denmar Struers A/S).The finite element simulation results for the strain region of the deformed specimen is also shown in α//{110}β and <11α//<111>β. The relationship between the α precipitated phase and the parent β phase has been reported in the lamellar microstructures and transformed microstructures of other titanium alloys [The initial microstructure information of the as-received alloy is shown in m alloys .−1. In contrast, the minimum peak stress was only 39 MPa at 880 °C, with a strain rate of 0.001 s−1. This trend is consistent with other titanium alloys [m alloys ,30. The m alloys , texturem alloys  and β rem alloys .−1, 0.01 s−1 and 0.1 s−1, respectively. The low strain rates allowed for sufficient time to achieve α/α interface separation, and then promoted dynamic spheroidization of the α lamellae. The deformation temperature also affected the aspect ratio of the α phase. When the stain rate was 0.001 s−1 and the deformation temperatures increased from 780 °C to 880 °C, the aspect ratio of the α phase decreased from 5.96 to 2.05 ). The percentage of HAGBs and the average misorientation of the α lamellae reached 68.4% and 43.07°, respectively ); this indicates that the occurrence of dynamic recrystallization is effective in reducing the distortion degree within the α phase. When the strain rate increased from 0.001 s−1 to 0.1 s−1, the percentage of HAGBs and the average misorientation decreased to 48.6% and 31.6°, respectively −1, the aspect ratio of the α phase was the smallest, at 2.05.The peak stress and the amount of flow softening decreased with increases in deformation temperature and decreases in strain rates. At 880 °C/0.001 s(2)The proportion of HAGBs decreased with increasing temperatures and strain rates, which was different from the trend of the spheroidization. Furthermore, the formation of HAGBs was not necessary for the spheroidization process. (3)The spheroidization mechanisms of α lamellae under high and low-temperature deformation conditions wererevealed, comprised of three steps: (i) the formation of sub-interfaces by dislocation slipping at 880 °C and by twinning at 780 °C, respectively, (ii) wedging of the β matrix along the α/α sub-interfaces and (iii) separation and spheroidization of the α phase.(4)The dependence of lamellar spheroidization on the crystallographic orientation tilt from the compression direction (θ) was clarified. When θ was between 45 and 60°, both the prism <a> slip and basal <a> slip systems were activated together, which was more favorable for spheroidization.In the present study, the dynamic spheroidization of a Ti-6Al-2Mo-2V-1Fe alloy during subtransus hot deformation, its mechanism and its orientation dependence were investigated. By detailed microstructure characterization and quantitative analysis, the following conclusions can be drawn:


To study the effects of highland barley flour with different particle sizes on dough characteristics and noodle quality, highland barley flours  were mixed with the wheat flour to make noodles. The damaged starch content of highland barley flour with five particle sizes was 47.0, 61.0, 62.3, 102.0, and 108.0 g/kg, respectively. The reconstituted flour containing highland barley powder with smaller particle sizes showed higher viscosity and water absorption. The smaller the particle size of barley flour, the lower the cooking yield, shear force and pasting enthalpy of the noodles, and the higher the hardness of the noodles. As the particle size of barley flour decreases, the structural density of the noodles increases. This study is expected to provide a constructive reference for the development of barley-wheat composite flour and the production of barley-wheat noodles. The noodles were one of the traditional Chinese dishes, and the main ingredients are wheat flour, water and salt. Meanwhile, noodles have a long history in East Asia and are one of the most important staple foods in China and other Asian countries. Among them, China makes up about 20–50% of the overall consumption of wheat flour in Asia ,2. In orParticle size, a critical parameter for measuring the flour characteristics, significantly affected the characteristics of dough and the product quality of the flour . These oPrevious studies on the particle size of highland barley flour (HBF) concentrated on its impact on the characteristics and nutritional properties of highland barley flour, but few studies examined the characteristics and product quality of reconstituted flour (RF). Therefore, 50% barley flour was used instead of wheat flour (WF) in this study, to investigate the effects of HBF particle size on the characteristics of reconstituted flour and noodles. The results of this study aim to provide references for the production of highland barley flour and highland barley-wheat noodles.Highland barley (Zangqing 2000) and Gluten was provided by Changdu Junqin Agricultural and Technology Development Co., Ltd. . The wheat flour was bought from Weifang Fengzheng Flour Co., Ltd. . The Rhodamine was purchased from Kolon Chemical Reagent Co., Ltd. . All other chemicals and reagents used in the experiments were of analytical grade.Highland barley kernels were sieved with a sieve to eliminate the impurities, then were milled by a hammer cyclone mill  one, three and six times, and were named HBF-1, HBF-2, and HBF-3, respectively. Next, HBF-3 was further milled with a flow mill  and named HBF-4, then the HBF-4 was ground for 3 min in an ultra-fine mill  and named HBF-5. Subsequently, the obtained flours were passed through stainless steel sieves with mesh sizes of 40, 60, 80, 100, and 120. Finally, HBF samples were packed in polypropylene bags and stored at 4 °C.The particle size distribution of HBF was determined with a particle size analyzer  following the method of Li et al.  with minThe morphology of HBF granules was observed using the SEM . Briefly, the highland barley powder was evenly fastened to the stage with double-sided adhesive, and gold-plated by ion sputtering, finally a representative image of 5000× was selected. An optimum ratio of HBF and WF of 1:1 was obtained through pre-experiments. On account of the lack of gluten protein in highland barley, it was calculated that 7.32 g of gluten flour should be instead of HBF to compensate for the missing gluten protein . Thus, each RF sample (100 g) contained 50 g wheat flour, 42.68 g HBF and 7.32 g gluten flour. The RF corresponding to HBF-1, HBF-2, HBF-3, HBF-4, and HBF-5 were named as RF-1, RF-2, RF-3, RF-4, RF-5, respectively.The optimal ratio of raw materials for noodles was 50 g wheat flour, 42.68 g HBF, 7.32 g gluten flour, 2.4 g salt and 40 g water. Before mixing, 2.4 g of salt dissolved in water. All ingredients were put in a dough mixer  and kneaded for three minutes. The dough was then covered with plastic wrap and left at room temperature (25 °C) for 15 min. Afterward, the dough was calendered through a pasta machine  and sheeted several times using a roll gap setting to obtain smooth dough sheets. Finally, the dough sheets were cut into 20.0 cm long, 2.0 mm wide, and 1.0 mm thick noodles and then dried in a drying chamber (40 °C) for 6 h. The reconstituted flour noodles (RFN) corresponding to RF-1, RF-2, RF-3, RF-4, and RF-5 were named as RFN-1, RFN-2, RFN-3, RFN-4, RFN-5, respectively. In the experiment, noodles made with wheat flour (WFN) served as a control. The pasting viscosities of RF were measured using a Rapid Visco Analyzer  according to the method reported by Chen et al.  with som1, C2, C3, C4, C5, Nm) for different periods were deduced from the recorded curves. Starch aging  and dough strength weakening  were calculated. Calculation of amylase activity  and anti-aging effect  was conducted.Mixolab  was used to measure the mixing characteristics of RF according to the method of Pu et al. . With th2 + (Δa*)2 + (Δb*)2]1/2. ΔL*, Δa* and Δb* indicate the differences in color values between WFN and RFN samples. The cooking properties of RF noodles were determined by referring to the method reported by Pu et al. [The color value  of dried RF noodles was measured by using a chroma meter . The color difference (ΔE) between WFN and RFN samples was calculated according to the formula: ΔE = [(ΔL*)u et al. . Broken The texture properties of cooked noodles were measured using a TA-XT2i texture analyzer . The noodles were cooked until the white core disappeared, then they were cooled and drained of excess water with filter paper and placed parallel on the measuring table. The calibration was set up with a 500 g load cell and a 15 mm return trigger path. TPA mode parameters : Speed oThe thermal properties of the dried noodles were assayed by differential scanning calorimetry  based on the method of Hemdane et al. . Dry floThe microstructure of the dried noodles was observed using scanning electron microscopy  using the method of Li et al. . The driw/w) Rhodamine B solution for 3 min, then rinsed with distilled water and wiped with filter paper, and images were taken. The excitation wavelength for the test was set to 561 nm. The CLSM images of noodle samples were processed and evaluated using the software “Angio Tool” .A confocal laser scanning microscope  was used to analyze the gluten structure of the dried noodles with minor modifications according to the method of Cao et al. . In briep < 0.05). Three independent tests were carried out for each sample group. Data analysis was processed by SPSS 17.0  and final data were presented as mean, standard ± deviation  (p < 0.05). It is well known that the increase in the grinding intensity will reduce the particle size of the powder granules. The median particle diameters of HBF-1 (223.25 μm), HBF-2 (143.12 μm) and HBF-3 (90.73 μm) declined gradually with increasing the number of milling treatments. However, it was noticeable that the median particle diameters of HBF-4 (42.33 μm) and HBF-5 (19.26 μm) showed a significant decrease due to the different crushing methods. Especially HBF-5 had no particles larger than 150 μm, and the most significant proportion of particles was between 10 and 30 µm. The damaged starch contents of HBF-1, HBF-2, HBF-3, HBF-4, and HBF-5 samples were 47.0, 61.0, 62.3, 102.0, and 108.0 g/kg, respectively. Damaged starch reflected the degree of starch crushing during grain crushing, and its excessive content would adversely affect the dough processing quality [p < 0.05) due to different types of crushing equipment.The difference in particle size plays a crucial role in the structure, porosity, specific surface area and even functional properties of powdery substances . The HBFof HBF-1 3.25 μm, The microstructure of the HBF is shown in In most cases, the RVA test is used to better understand the changes in the viscosity of the flour or starch solutions during heating and cooling, as well as to predict the quality of noodles ,25. Durip < 0.05). It is probably due to the water absorption and swelling of damaged starch, resulting in the increase in RF viscosity. In addition, as the particle size of highland barley flour decreased, the crystal structure was destroyed, and water penetrated more easily, intensifying the occurrence of pasting [ pasting . In addi pasting . The set pasting . This ph2 were used to predict the quality of gluten. The C3, C5 and C5-C4 parameters stand for the starch gelatinization properties of the RF system as it was heated and cooled [The Mixolab test could offer information on dough mixing behaviors. In the test, the torque generated when the dough passed through the two kneading arms was recorded to study the mixing and pasting properties of the flour. Detailed representation of the regular changes measured by Mixolab and the associated parameters were investigated and reported by Rosell et al. . The pard cooled .p < 0.05). Compared with the WF group with a WA of 59.4, the WA increased by 12.12%, 16.72%, 17.29%, 20.37% and 21.94% in the HBF-1, HBF-2, HBF-3, HBF-4 and HBF-5 groups, respectively. This was mainly due to the increase in impaired starch with decreasing particle size, leading to the destruction of starch structure and the breakage of molecular starch chains. This resulted in higher exposure of hydrophilic groups in the RF. This conclusion was consistent with that reported by Cai et al. [2 represents the loss of dough consistency when exposed to both physical-mechanical and thermal stresses [2 values of RF were lower and did not significantly (p > 0.05) change with the decrease in HBF particle size. During the heating process of the Mixolab test, C3 indicated the degree of starch gelatinization and C3-C4 represented the amylase activity. With the decreasing of HBF particle size, the C3-C4 value was decreased and the C5-C4 value was increased. This may be due to the release of powdered amylase from HBF, which increased the activity of starch hydrolysis into small molecules . It further promoted dough fermentation and eventually reduced the starch concentration and pasting viscosity [5 and C5-C4 decreased sequentially, suggesting that the addition of small particles of HBF was less prone to aging, which was beneficial to extend the shelf life of flour products. The discrepancy between the results of these two types of research might arise from the effect of bran size variation or the content of damaged starch on gluten starch regeneration. In this study, the content of damaged starch seemed to play a more vital role than the bran size of HBF.The Mixolab measurement results for different RF samples are shown in i et al. . The DT i et al. . Besidesstresses . Compareiscosity . Howeveriscosity , RF-1 top < 0.05). It may be due to the larger particle size and less damage of HBF-1 and HBF-2, where the pigment component of the bran was not fully exposed. The ΔE values of RFN samples were described as RFN-3 > RFN-5 > RFN-4 > RFN-1 = RFN-2. This shows that the particle size and damage rate of HBF had a greater effect on the color of RFN.Noodles with rich nutrition and bright color were generally more acceptable to consumers. Wheat flour contains yellow pigments such as lutein and carotene. Based on the multiple conjugated double bonds of these compounds, wheat flour was pale yellow in appearance . It coulp < 0.05), and the results suggested that highland barley flour exhibits higher cooking tolerance than wheat flour during cooking.The cooking performance of noodles prepared with different types of RF was measured to better understand the effect of different particle sizes of HBF on the final product quality. Generally speaking, crushing rate, cooking loss, cooking rate, and optimal cooking time were the important criteria for consumers and the industry to evaluate the quality and cooking characteristics of the noodles ,35. The p < 0.05), which probably explained that the fibers in HBF could enhance the hardness of noodles. The hardness of RFN increased with decreasing particle size of HBF, which was in line with the results reported by Chen et al. [The textural properties  of the cooked noodles’ components are shown in n et al. . Yan et n et al.  found thn et al. . HighlanThe effect of highland barley flour with different particle sizes on the thermal properties of noodles is shown in The microstructure and morphology of the noodles are shown in p > 0.05). This phenomenon indicated that HBF with larger particle size disrupted gluten stability and uniformity during dough formation, while HBF with smaller particle size was more favorable to the cross-linking of gluten to form a dense network structure. Since bran endpoints were open protein threads, they were often used as a valid reference for measuring network cohesion [The CLSM images of noodles samples were processed and quantified with “AngioTool” to obtain seven parameters , enablincohesion . The numcohesion . The laccohesion ,44,45. IDifferences were found in the physical-chemical properties of barley flour with different particle sizes, including damaged starch content, morphological characteristics and pasting properties. In addition, the particle size of highland barley flour had impacts on the color, cooking properties, textural characteristics, thermal features and internal structure of noodles. It showed that the particle size could be used as an important parameter to describe the characteristics of wheat-highland barley flour and wheat-highland barley noodles. The relevant research results in this study can provide ideas for the development of highland barley noodles with different features, so as to promote the unconventional application of highland barley flour and improve the economic benefits of highland barley. This work explored the effect of whole highland barley flour on the characteristics of reconstituted flour and noodles. However, the main components in highland barley flour  have different characteristics. The effect of these individual factors on the whole dough system is still unclear, and related studies will be carried out in the future.


The elastic deformation of the levitation electromagnet (LM) of the high-speed maglev vehicle brings uneven levitation gaps and displacement differences between measured gap signals and the real gap in the middle of the LM, and then reduces dynamic performances of the electromagnetic levitation unit. However, most of the published literature has paid little attention to the dynamic deformation of the LM under complex line conditions. In this paper, considering the flexibility of the LM and the levitation bogie, a rigid-flexible coupled dynamic model is established to simulate deformation behaviors of the LMs of the maglev vehicle passing through the 650 m radius horizontal curve. Simulated results indicate that the deflection deformation direction of the same LM on the front transition curve is always opposite to that on the rear transition curve. Similarly, the deflection deformation direction of a left LM on the transition curve is opposite to that of the corresponding right LM. Furthermore, deflection deformation amplitudes of the LMs in the middle of the vehicle are always very small (less than 0.2 mm). However, the deflection deformation of the LMs at both ends of the vehicle is considerably large, and the maximum deflection deformation is about 0.86 mm when the vehicle passes at the balance speed. This forms a considerable displacement disturbance for the nominal levitation gap of 10 mm. It is necessary to optimize the supporting structure of the LM at the end of the maglev train in the future. The electromagnetically suspended (EMS) maglev train utilizes magnetic attraction forces between the on-board electromagnets and the ferromagnetic rails to support and guide vehicles, the non-contact magnetic forces avoid mechanical impact, noise, and wear caused by the wheel-rail contact in traditional rail transportation. Furthermore, high-speed EMS maglev train is propelled by the linear synchronous motor, so it can be easily accelerated to over 500 km/h without derailment risk. However, since the open-loop electromagnetic levitation system is inherently unstable, feedback controllers must be used to regulate coil currents of the electromagnets for maintaining about a 10 mm levitation gap. In order to improve the loading capacity of the maglev vehicle, many levitation electromagnets (LMs) are continuously arranged along both undersides of the vehicle; meanwhile, the lightweight electromagnet is necessary. As for the German TR08 maglev vehicle, each levitation bogie is installed with a pair of LMs; moreover, two adjacent levitation bogies are lapped by the other pair of LMs . GeneralHowever, most of the previous research on the maglev vehicle dynamic simulation simplifies or ignores the flexibility of the LM and the levitation bogie . In ordeIn this paper, a rigid-flexible coupled dynamic model is built firstly according to the Shanghai TR08 high-speed maglev vehicle. It considers the flexibility of the levitation bogie and the LM. Subsequently, the model is used to simulate the dynamic response of maglev vehicle passing through a 650 m radius horizontal curve at three typical running speeds. Furthermore, dynamic deformation behaviors of all the LMs of the maglev vehicle are presented and discussed in detail, including the local deformation, the overall deflection deformation, the deflection amplitude distribution of all the LMs, and the change laws of the deflection deformation with the curve-passing speed. Thus, this study provides comprehensive insights into elastic deformation behaviors of the running parts of a maglev vehicle passing through the horizontal curve under various operating conditions.The Shanghai maglev line adopting German TR08 maglev technology has operated successfully for over twenty years at speeds of up to 430 km/h , and the2 [As shown in 2 . Based o2 . The dyn2 , thus itGenerally, a floating reference frame is set up to depict the rigid body motions of a flexible body and its elastic deformation. As for the LM, an undeformed marker is set at its geometric center as the floating reference frame. In order to analyze the local and global deformation of the LM, five measuring points marked as the C1~C5 point are set at the front end, the 1/4, 1/2, and 3/4 length, and the rear end of the LM. It should be pointed out that the simulated results of elastic deformation of all the LMs in this study are dynamic components, namely, static deformation under the initial equilibrium loads is not considered in the following numerical simulation because it is almost eliminated by the pre-camber of the LM.Using the flexible body dynamic model shown in N denotes the turn number of pole coil, A is the effective area of the magnetic pole, I is the coil current, and c expresses the air gap.The dynamic model of the independent levitation control unit involves a calculation module of magnetic force and a levitation control module. Assuming the air gap between the lower surface of the stator parts and a magnetic pole is uniform, meanwhile, nonlinear magnetization characteristics of the iron core and the stator parts are ignored, and then the magnetic attractive force acting on the magnetic pole can be calculated by:δ(t) is the air gap variation and a(t) is the electromagnet acceleration. Kp, Ki, and Kd denote, respectively, the proportional coefficient, the integral coefficient, and the differential coefficient. Ka is the feedback coefficient of electromagnet acceleration.When Formula (1) is adopted to calculate the magnetic forces of the SLM, including 12 concentrated magnetic forces acting respectively on 12 magnetic poles, the current of the front (rear) six magnetic pole coils is the same, which is regulated independently by the front (rear) levitation controller. Generally, the levitation control system uses a double-loop controller comprised of a position loop and a current loop ,19, as sBased on the magnetic force calculation formula listed in Formula (1) and the levitation control algorithm shown in The sharp horizontal curve can create strong geometric constraints for maglev vehicles, and then leads to large load variations and elastic deformation of the LMs. Hence, according to China’s Standard for Design of High-speed Maglev Transit (CJJ/T310-2021) [k denotes the curvature on the position of the l arc length away from the starting point, Rc is the radius of the circular curve, and Lt is the length of the transition curve. The horizontal curve for high-speed EMS maglev transportation adopts the one-sine-wave type transition curve , the curθc is the constant transverse slope on the circular curve. Equation (5) indicates that the changing rate at the midpoint of the transition curve reaches the maximum value, which is 0.1 °/m  for the aforementioned horizontal curve with a radius of 650 m.The transition curve track twists around the route centerline; meanwhile, the transverse slope (superelevation angle) is generated to counteract the centrifugal force acting on the moving vehicle. Generally, the transverse slope increases gradually along the longitudinal direction by a function similar to Equation (3), and the changing rate of transverse slope can be calculated by:ayu). If ayu is zero under the condition of a certain curve-passing speed, the speed is named the balancing speed. In order to obtain good passenger ride comfort, ayu is specified in the range from −0.5 m/s2 (pointing to the inside of the curve) to 1.0 m/s2 (pointing to the outside of the curve) [When the maglev vehicle runs on a circular curve with a constant transverse slope, the lateral acceleration of the carbody is approximately equal to the difference between the centrifugal acceleration and the lateral component of gravitational acceleration, called the unbalanced lateral acceleration (e curve) . Thus, tUsing the rigid-flexible dynamic model of the maglev vehicle and the 650 m radius horizontal curve model, the dynamic responses of maglev vehicles are simulated to figure out the primary deformation features of the LMs under three running speed conditions of 67 km/h, 93 km/h , and 130 km/h. The deflection deformation of all the LMs will be discussed in more detail because they could create considerable air gap differences among the 12 or 14 magnet poles of an LM.When the maglev vehicle passes through the 650 m radius horizontal curve at the balancing speed (93 km/h), simulated results indicate that the elastic deformation responses of the LMs at both ends of maglev vehicle are fairly close, but they are significantly greater than those of the other LMs. Thus, the L1 and R1 LMs are selected to analyze their local deformation behaviors. In order to analyze the deflection deformation of an LM, the vertical deformation differences between the C1, C5, and the C3 points of the LM are calculated at a time step, and the larger of them is defined as the deflection deformation value of the LM at the moment. It can be also found from Considering the flexible characteristics of the LM and the levitation bogie, a rigid-flexible coupled dynamic model is established to simulate the dynamic responses of a high-speed maglev vehicle passing the 650 m radius horizontal curve at three typical running speeds. In particular, elastic deformation behaviors of the LMs are analyzed thoroughly, and the following conclusions can be drawn from this study.When the high-speed maglev vehicle passes through the horizontal curve at the balancing speed (93 km/h), all the LMs have larger dynamic deformation on the front and rear transition curves. Moreover, dynamic deformation peaks  of the LMs at both ends of the vehicle are much greater than those of the LMs in the middle. The maximum deflection deformation of all the LMs always appears near the midpoint of the transition curves, which is about 0.7 mm. Furthermore, the deflection deformation direction of the same LM on the front transition curve is always opposite to that on the rear transition curve, which means all the LMs incur upward and downward deflection deformation. Similarly, the deflection deformation direction of a certain left LM on the front or rear transition curve is opposite to that of the corresponding right LM.When the running speed of the maglev vehicle increases from the balancing speed to the maximum allowable speed (130 km/h), deflection response curves of the left LMs shift upward and those of the right LMs shift downward due to the deficient superelevation on the horizontal curve. Compared with the deflection deformation of the LMs in the case of the balancing speed, the maximum deflection deformation of the LM at both ends  of the vehicle increases by 21.0%, 22.3%, 17.4%, and 18.0%, respectively, while the deflection deformation of the LMs on the circular curve also increases significantly. In addition, when the running speed decreases from the balancing speed to the minimum allowable speed (67 km/h), deflection response curves of the left LMs shift downward and those of the right LMs shift upward due to the surplus superelevation on the horizontal curve. The maximum deflection deformation of the L1 and L7 LMs decreases by 8.6% and 8.7%, and that of the R1 and R7 LMs increases by 1.0% and 0.9% compared with those in the case of the balancing speed.V ≤ 130 km/h), dynamic local deformation and overall deflection deformation of the LMs in the middle of the vehicle are very small, and they are usually less than 0.2 mm. However, the elastic deformation of the LMs at both ends  of the vehicle is relatively large, and the maximum deflection deformation is close to 0.9 mm, which is greater than the specified limit of 0.5 mm. If more external excitations, such as track irregularities, dynamic deflection of guideway girder, and wind loads, are considered in the dynamic model of a maglev vehicle system, the deflection deformation of the LMs at both ends of the vehicle would exceed 1.0 mm, which is a considerable displacement disturbance for the nominal levitation gap of 10 mm. Hence, it is necessary to optimize the supporting structure of the LM at the end of the maglev train in the future. The purpose of any optimization is to reduce the deformation of the electromagnet. From the perspective of mechanical structure, the support structure under the magnetic pole can be designed separately for the LLM to improve the bending stiffness, including using materials with higher elastic modulus, optimizing the section shape, and increasing the wall thickness. In addition, the arrangement of the sensor can be optimized so that the current of the controller is more specific to the levitation gap of each section of the electromagnet.In sum, when the maglev vehicle passes through the horizontal curve at the allowable normal running speeds (67 km/h ≤


Reader domains that recognize methylated lysine and arginine residues on histones play a role in the recruitment, stabilization, and regulation of chromatin regulatory proteins. Targeting reader proteins with small molecule and peptidomimetic inhibitors has enabled the elucidation of the structure and function of specific domains and uncovered their role in diseases. Recent progress towards chemical probes that target readers of lysine methylation, including the Royal family and plant homeodomains (PHD), is discussed here. We highlight recently developed covalent cyclic peptide inhibitors of a plant homeodomain. Additionally, inhibitors targeting previously untargeted Tudor domains and chromodomains are discussed. Post-translational modifications (PTMs) to histone proteins are inserted, removed, and recognized by epigenetic proteins. These marks influence chromatin structure and function and regulate gene expression. One of the most common histone PTMs is the methylation of lysine residues, which is installed and removed by histone lysine methyltransferases and histone lysine demethylases, respectively. Proteins that “write” or “erase” methyl marks may also contain “reader” modules that play a role in recruiting effector proteins to chromatin or stabilizing histone binding, as well as regulating catalytic activities through allosteric mechanisms . HistoneWhile the cellular functions of some reader domains are still being elucidated, many are implicated in disease development and progression ,5. In or4-His-Cys3 zinc fingers that coordinate two zinc ions. PHD fingers bind the H3 N-terminal tail, mainly recognizing unmodified H3K4 and H3K4me2/3, with a small subset recognizing unmodified H3R2, H3K9me3 and H3K14ac, with high nanomolar to low micromolar affinity . Al. Al31]. nM, SPR) . The cycmization .The MBT domain consists of about 100 amino acid residues and is present as 2–4 repeats in 9 human proteins . MBT domKd = 120 nM, ITC), which binds as a 2:2 complex with two separate molecules of 3MBT  able to engage SPIN1 in cells , which binds Tudor domain 2 of SPIN1 with high selectivity    50]. Vi. ViKd = R,R)-59, a potent and selective small molecule inhibitor of SETDB1-TTD, was developed -59 binds with nanomolar affinity  in the domain 2 and domain 3 region, occupying the aromatic cage of domain 2. -59 inhibited histone binding to SETDB1-TTD and exhibited target engagement in cells.The triple Tudor domains of SETDB1 recognizes histone tails with K14ac in a deep cavity at the interface of domains 2 and 3 and K9me1/2 via the aromatic cage of domain 3 or K9me3 via domain 2 . The fireveloped  and 3d . UN. UNKd ~ in cells ,63.Kd = 800 nM) with >5-fold selectivity over other CBX paralogs  approach was used to discover a potent peptidomimetic ligand, SW2_110A, for CBX8  is modestly selective for HP1 CBXs over PcG CBXs (Kd = 0.72 μM (ITC), but also binds CDYL2 about 4-fold more potently (Similar peptidomimetic strategies have been applied to the chromodomains of the HP1 family (CBX1/3/5), CDY family, and to MPP8, a human silencing hub (HUSH) complex member. CBX5-targeting ligand UNC7560 -59, has also been successful. Another challenging aspect of targeting reader domains are their extended, surface-exposed binding sites. PHD fingers display shallow binding grooves, suggesting that peptidomimetics may be a more tractable approach to target this class of reader domains, similar to the approach taken with chromodomain peptidic inhibitors. Despite their large size, chromodomain chemical probes retain cell permeability, a significant challenge encountered with peptidomimetics. An alternative and potentially useful strategy is to repurpose weak-binding ligands into PROTAC compounds with cellular efficacy. Based on the observation that EED-targeted PROTACs can also degrade other components of the PRC2 complex, the generality of the complex degradation by reader-directed PROTACs warrants further investigation [Epigenetic proteins often contain multiple reader domains that recognize multiple histone marks, either as isolated domains or in tandem. Utilizing multi-domain proteins in the discovery and/or selectivity assays may lead to more promising hits that can be developed into chemical probes and may also lead to inhibitors that target domain–domain interfaces . Targetitigation ,74. Targ


Research on typically developing children and adults and people with developmental and acquired dyscalculia converges in indicating that arithmetical ability is not unitary but is made up of many different components. Categories of components include non-symbolic quantity representation and processing; symbolic quantity representation and processing; counting procedures and principles; arithmetic operations; arithmetical knowledge and understanding; multiple forms and applications of conceptual knowledge of arithmetic; and domain-general abilities such as attention, executive functions and working memory. There is much evidence that different components can and often do show considerable functional independence, not only in developmental and acquired dyscalculia, but in typically achieving children and adults. At the same time, it is possible to find complex interactions and bidirectional relationships between the different components, including between domain-specific and apparently domain-general abilities. There is a great deal that still needs to be discovered. In particular, we need to learn more about the origins in infancy of subitizing and approximate magnitude comparison, the extent to which these interact, the extent to which they may be further divisible, and the extent and ways in which they themselves may develop with age and the extent to which they may influence later-developing components. There also needs to be a lot more research on exactly how domain-general and domain-specific abilities contribute to mathematical development, and how they interact with one another. Research on typically developing children and adults and people with developmental and acquired dyscalculia converges in indicating that arithmetical ability is not unitary but is made up of many different components , 2015. FThis paper will discuss some of the more important components of arithmetical cognition, and some of the ways in which they can dissociate in typical and atypical development and functioning. It is not intended to provide a complete list of these components, from the point of view of psychology, education or mathematics. Indeed it is questionable whether a full and definitive list of such components can exist.The main components of arithmetical cognition are sometimes grouped into the categories of factual, procedural and conceptual knowledge  but eachThere is indeed overwhelming evidence that arithmetical ability Is not unitary e.g., . Rather,Although this article focuses mainly on the componential nature of arithmetical cognition in a broad sense, there is evidence that different specific aspects of arithmetic itself can dissociate. Patients can demonstrate specific impairments in different arithmetical operations: addition, subtraction, multiplication or division. Patients also sometimes show deficits in particular aspects of an arithmetical operation, such as carrying in addition or borrowing in subtraction. For example, Though most studies of specific weaknesses in arithmetical operations and their components have involved neuropsychological patients, such weaknesses also occur in apparently typically developing children and adults. For example, The focus of this article is on whole number arithmetic; but fractions and decimals, and the use of arithmetical operations in dealing with them, are usually more difficult for people to handle, both conceptually and procedurally .In particular, studies of both atypical and typical mathematical development in children have indicated that from an early age, arithmetical cognition is already made up of multiple components . For exaIt may be that in typical mathematical development, the components inform and integrate with each other to a greater extent than they do in delayed or atypical mathematical development. In the latter situation, either the integrative process itself may not work as effectively, or it may be impaired by weakness in the individual components. It would be desirable to investigate whether these differences between children with and with and without mathematical difficulties, with regard to the level of association between components, would be replicated in different samples and age-groups. If so, do weaknesses in individual components impede integration, or does integration failure impede progress in the individual components, or both?An interesting question is whether numeracy is already componential in the preschool years, with regard to counting procedures and concepts. Scores on most tasks correlated significantly, but discrepancies in both directions occurred between almost any two tasks. For almost any pair of tasks, there were children who could perform either one of the tasks but not the other. For example, proficiency in counting objects correlated significantly with performance on the cardinal word principle task, but 22% of proficient counters were “grabbers” on the cardinal word task, and 41% of nonproficient counters were “counters” on the cardinal word task.As indicated at the beginning of this article, some strong evidence for the componential nature of arithmetical cognition comes from selective impairments of specific aspects of arithmetical cognition in patients with brain damage. Patients have demonstrated double dissociations between factual and procedural knowledge  and betwDissociations between different components of arithmetical knowledge and processing have been found not only in patients with focal brain lesions but in those with neurodegenerative disorders. People with hippocampal damage, either due to injury or to atrophy (the latter often associated with early Alzheimer’s disease) are often unimpaired in retrieval of well-learned arithmetical facts, such as multiplication tables. There may be a distinction, with regard to arithmetical facts as with regard to other types of factual information, between the ability to lay down arithmetical facts and the ability to retrieve well-consolidated arithmetical facts. While there is no invariable one-to-one relationship between specific brain areas and specific aspects of numerical cognition, much research suggests the importance of parietal areas, and especially the intraparietal sulcus (IPS) in basic numerical tasks including quantity and numerical comparisons and single digit arithmetic. It may also be important in more complex computational estimation. Brain imaging studies of healthy people also suggest that different brain networks may support different aspects of arithmetic and number processing. Dehaene and colleagues carried out functional MRI and ERP studies of approximation and exact calculation in healthy individuals . ParietaOf course, activation of particular brain areas during a particular mathematical task does not necessarily mean that these areas are specialized for particular components of mathematics. They could be supporting non-numerical, domain-general processes relevant to the task in question. In order to understand the componential nature of numerical ability, it is important to gain a greater understanding of its earliest foundations. We have evidence from developmental studies, discussed above, that numerical abilities are already componential in the preschool years. But are they so from the beginning? One unresolved question is whether symbolic number representation grows directly out of non-symbolic number representation or should be regarded as a separate skill or combination of skills. There is also the perhaps even more fundamental question of whether the primary foundational ability is subitizing or approximate number representation or whether, as seems most likely, both are crucial: i.e., numerical ability is componential from its foundations. Despite the likelihood that both subitizing and the approximate number system are at the foundations of arithmetical development, there is evidence that later arithmetical abilities can show considerable functional independence from both.Humans’ ability to enumerate visual stimuli involves not only verbal counting, but on two nonverbal quantity recognition processes: the Approximate Number System (ANS) , which iFor example, some studies of both children and adults suggest that non-symbolic number comparison abilities are only weakly related to symbolic comparison and to arithmetic. There are still some disagreements about the nature of subitizing and about how far the subitizing range extends. Many studies of subitizing have involved infants. Most of these studies indicate that babies can distinguish quantities up to 3 , though Many researchers consider that different underlying processes support subitizing and counting. Some researchers, such as Some neuropsychological evidence supports a dissociation between subitizing and counting. Evidence from brain imaging studies of healthy individuals is somewhat conflicting. Despite the findings mentioned above, it is likely that the two processes are still linked to some degree. There is substantial evidence that counting relies on the accurate development of subitizing. This may be due to some underlying neuropsychological similarities or the foundational nature of abilities that support numerical representations, one of which is an innate capacity to represent small numerosities. This capacity is demonstrated in subitizing tasks; and A number of studies have shown links between subitizing and various other aspects of mathematical ability . For exaIn line with these findings, problems in subitizing have been identified in some children and adults with developmental dyscalculia. If subitizing is important in the development of some or all aspects of arithmetic, one might expect that training in subitizing might improve mathematical performance . Özdem aSubitizing itself may be componential and not a single entity. three such systems: one for numerosities under 4; one for high numerosities, and one for intermediate numerosities such as those between 10 and 20. They suggest that the intermediate numerosity system may rely less on attention than either the low or high numerosity system. As evidence for this proposal, they use findings that performing a distracting concurrent task impaired typical adults’ numerosity judgment performance much more for low or high numerosities than for intermediate numerosities. They also studied a simultagnosic patient and found that his ability to compare either very low or very high numerosities was seriously impaired, while showing relatively preserved ability to compare intermediate numerosities.A crucial question is whether the ability to compare non-symbolic number magnitudes  is a strong predictor of numerical abilities, as might be suggested by Most studies do, however suggest a predictive role for non-symbolic number comparison with regard to later symbolic arithmetical abilities . In lineSeveral studies have shown that children with a diagnosis of dyscalculia are often impaired at approximate comparison of sets of dots . Some stThere is, indeed, increasing evidence that non-symbolic magnitude comparison may not be totally domain-specific, but may also depend on executive functions, such as inhibition, enabling one to focus on the dimension of quantity and to ignore other aspects of stimuli, such as contour and area. Indeed, numerosity-irrelevant perceptual properties of continuous quantity have been found to increase the difficulty of numerical processing not only in young children but even in adults.Another important question to be discussed here, with regard to the componential nature of arithmetical and numerical abilities, is whether discrepancies between different numerical tasks are most likely to reflect strengths and weaknesses in domain-specific numerical abilities or to be secondary to strengths and weaknesses in domain-general cognitive abilities. This question arises both with regard to typically developing children and adults and with regard to people with developmental and acquired dyscalculia.Domain general abilities make a significant contribution to numerical and arithmetical cognition. At one time, the main domain-general ability studied with regard to numerical cognition was logical reasoning. For example, Domain general abilities may help to explain discrepancies between different components of arithmetic itself: for example, between different operations. There are often alternative possible explanations for discrepancies between different operations, which relate to more domain-general abilities. Multiplication may dissociate from other operations because it is usually learned in ways that emphasize verbal rote learning to a greater extent than other operations, and thus may rely more than other operation on verbal skills. Domain general abilities appear to play an important role, and to interact with domain specific abilities, in an even more complex way with regard to components of arithmetical cognition in a broader sense. A number of studies have indicated the importance of both domain general and domain specific skills in early mathematical development. Attentional abilities are generally found to be important to arithmetical development . Hassingworking memory is a significant predictor of arithmetic (Most studies show that ithmetic . Both veDifferent aspects of working memory may predict different aspects of mathematical development and performance. As well as working memory. Other executive functions are also highly important to mathematical skills Many studies indicate that executive functions are related both cross-sectionally and longitudinally to arithmetical performance . SeveralThe role of inhibition might seem at first. to be particularly important for mathematical skills such as word problem solving, where it is necessary to sift text for relevant information. However, its importance is by no means confined to such verbal tasks and can even be seen in very young children’s elementary numerical abilities. specific aspects of numerical ability., though the evidence is conflicting as regards which aspects they predict, and how these are related to one another. There is also some evidence that executive functions in general, and inhibition in particular, are particularly important predictors of There is now considerable interest in the associations between mathematical performance and both domain general and domain specific abilities. Most studies have dealt with the extent to which children’s mathematical performance and progress are predicted by such abilities. Overall, studies indicate that both are important, but it is difficult to draw firm conclusions about the relative importance of different predictors. This is because studies differ with regard to the exact domain-specific abilities being investigated; the exact domain-general abilities being investigated; the mathematical performance measures being used; the children’s age group; and the culture and school curriculum in which they are operating.Path analysis mediation models indicated that all the predictors were significant, but that numerical cognition, mediated the effects of processing speed, working memory, calculation skill, word-problem solving, and attentive behavior on all three outcomes. Most studies in the area have involved British or American pupils. It is possible that different countries and cultures might show different relationships between mathematical achievement and domain specific and domain general predictors, both because of differences in the curriculum and because of differences in out-of-school experiences and activities. Studies of patients also suggest that both domain-general and domain-specific abilities are important to performance in basic numerical tasks. The distinction between “domain-general” and “domain-specific” may itself be over-simplified, Some researchers are now investigating the role of such “number specific executive functions” separately from executive functions in a non-numerical context, and domain-specific numerical abilities. For example. Components of arithmetical cognition come into several important categories, shown in We have gained a lot of knowledge about numerical cognition and its componential nature; but there is a great deal that still needs to be discovered. In particular, we need to learn more about the origins in infancy of subitizing and approximate magnitude comparison, the extent to which these interact, the extent to which they may be further divisible, and the extent and ways in which they themselves may develop with age and the extent to which they may influence later-developing components.There also needs to be a lot more research on exactly how domain-general and domain-specific abilities contribute to mathematical development, and how they interact with one another. It is certain that both domain-general and domain-specific abilities are involved. There are, however, many unanswered questions about how they relate to one another; the extent to which they may have differential effects on different arithmetical skills; the extent to which they may have differential effects at different ages; the extent to which they may play different roles in developmental dyscalculia and in typical development; and the relative importance of different domain-general abilities. As regards the latter, the greatest focus in research has been on working memory. Other executive functions, attention, and spatial ability, but, as It is also important to study numerical development and cognition in a wider variety of environments, contexts and cultures .Finally, although this article deals just with numerical cognition, it is important to study other aspects of mathematical cognition, including geometry, spatial cognition, pattern awareness and algebra-related concepts. Most of these have received far less study than number. It is also important to gain a greater understanding of relationships between emotional and cognitive factors in mathematics .The author confirms being the sole contributor of this work and has approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The number of dangling bonds is well-modulated by controlling the post-metallization time. Zn-TDCOF-12 shows one of the highest sensitivities to NO2 in all reported chemiresistive gas sensing materials operating under visible light and room temperature. This work opens an avenue to rationally design a dangling bond in COF materials, which could increase the active sites and improve the mass transport in COFs to remarkably promote their various chemical applications.Dangling bond formation for COF materials in a rational manner is an enormous challenge, especially through post-treatment which is a facile strategy while has not been reported yet. In this work, a “chemical scissor” strategy is proposed for the first time to rationally design dangling bonds in COF materials. It is found that Zn A facile “chemical scissor” strategy is first proposed to rationally design a dangling bond for COF materials, which remarkably promotes their gas sensing performance. Among them, dangling bond formation is possible to not only increase the active sites, but also create the desired hierarchical pore structures16 to improve the mass transfer of COFs in various chemical applications.Covalent organic frameworks (COFs), a class of porous crystalline materials constructed from organic molecules by strong covalent bonds, have been widely investigated.17–20 which enhances the performances and even generates new properties.21,22 In the fields of MOF materials, researchers usually use de novo synthesis and post-synthetic treatment to create dangling bonds in MOFs to improve the performance of materials.23 However, reports of rational dangling bond formation on COFs are still rare and mainly limited in the use of the monomer-truncation strategy.15,24–28 Commonly, this strategy requires introduction of additional monomers in the COF synthesis, which requires twiddly design and preparation.26 Comparatively, post-treatment methods, such as ultrasound, soaking  and heating, reported for other material systems, are relatively simpler for dangling bond formation.29,30 However, the traditional post-treatment methods normally create dangling bonds by randomly breaking the covalent bonds in the framework and cannot achieve rational tailoring of the target bonds. It is still an enormous challenge to realize rational dangling bond formation through a post-treatment method.Dangling bond formation has played a critical role in the tailoring properties of various materials,31 it was revealed that the metal sites at the porphyrin centers of a series of COFs were the critical sensing sites. Co–COF with Co site has the highest NO2 adsorption energy and thus shows the highest sensitivity. However, we found a very surprising result in Zn–COF with Zn sites. In the dark, the NO2 adsorption energy of Co is much higher than that of Zn, but the sensing response of Co–COF is not as good as that of Zn–COF (for details see the section about the performances of chemiresistive gas sensing). More interestingly, other COF materials in our study showed reversible gas sensing response. Meanwhile, Zn–COF with a relative smaller NO2 adsorption energy than other COFs showed a unreversible gas sensing reaction. These unusual results suggest a completely different gas sensing mechanism of Zn–COF from these of other COFs in our previous work.One of the biggest advantages of COF materials in performance research is that their porous structure enables effective revelation of the structure–property relationship. In our previous work,2+ in a protonic solvent to hydrolyze the target imine bond. The treated sample, Zn-TDCOF-x (x stands for the treatment time with the unit of an hour) shows the rational fracture of target imine bonds, dramatically increased dangling bonds and hierarchical pore structures. The number of dangling bonds and porosity could be well modulated by controlling the post-treatment time. As an exemplary chemical application, Zn-TDCOF-x was used as a chemiresistive gas sensing material to detect NO2. Its sensitivity was deeply modulated by controlling the number of dangling bonds and shows one of the highest sensitivities in all reported NO2 sensing materials working under visible light and room temperature. A detailed study on the control samples with a thermal gravimetric analyzer (TGA) on a MEMS cantilever, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) and density functional theory (DFT) calculations reveals the mechanism of dangling bond formation in TDCOF through the “chemical scissor” strategy and the origin of the gas sensing ability from the dangling bonds. Compared with directly obtaining low crystallinity and amorphous materials, the advantage of preparing Zn-TDCOF by the “chemical scissor” strategy are: (1) the porous structure facilitates exploration of the structure–property relationship and gas enrichment; (2) good charge transfer is obtained by reasonable design of dangling bonds.In order to further explore the effect of the intrinsic structure–activity relationship of Zn–COF on gas sensing, we propose a facile “chemical scissor” strategy to rationally design a dangling bond for COF materials. The “chemical scissor” strategy works by post-metallizing a COF based on a coordination reaction, which activates the target covalent bond through elongating its lengths to prompt its fracture in the subsequent hydrolysis reaction . Based o31 In the crystal structure of TDCOF, one TAPP connects to four DFPs or one DFP connects to two TAPPs through imine bonds to present 2D π-conjugated macromolecular layers. These layers pack with each other at a distance of 0.403 nm  shows that the phases of TDCOF and Zn-TDCOF-x are consistent with that of simulated TDCOF  scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>NC = 1622 cm−1) in FT-IR spectra proves the existence of imine linkages of TDCOF and Zn-TDCOF-x 32 in XPS demonstrates the successful modification of Zn2+ into the structure of Zn-TDCOF-x. For example, the Zn 2p3/2 binding energy of Zn-TDCOF-12 (1021.7 eV) deviates from that of the reactant, zinc acetate (1022.3 eV), which is attributed to the change in the coordination of Zn species from with oxygen (zinc acetate) to nitrogen atoms (Zn-TDCOF-12)  are detected for 0.51, 0.95, 1.37 and 1.82 wt%, respectively, through inductively coupled plasma emission spectrometer (ICP) analyses porphyrin (TAPP) and 2,6-diformylpyridine (DFP) based on a Schiff base reaction under solvothermal conditions (for details see the Method section).0.403 nm . The posF Fig. S1. The peax Fig. S2. The hig) Fig. S3.33,34 Men Fig. S4.35,36 Be Table S1.x were characterized through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. TDCOF presents a 3D crumpled nanosheet morphology. With increase of modification time from 6 to 15 h, the morphologies of Zn-TDCOF-x are almost the same as that of TDCOF  of 813 m2 g−1 and pore size distribution fitted at 1.1 nm, which matches with the pore size in the simulated structure of TDCOF (1.2 nm)  (V–2NH = 3300–3500 cm−1) in the FT-IR spectrum  and experimental details can be seen from the quantitative analysis of dangling bonds in the ESI.2) increases gradually (−1) is 6.2 times larger than that of TDCOF (37 μmol g−1)  . The ami Fig. S18. The amoradually . For examol g−1) . These r Table S4.41,42 Wi Table S4. This re2+ is critical in the hydrolyzation reaction and acts as a “inducer” to break the imine bond in the framework of TDCOF to form –NH2 groups through the treatment of EtOH and H2O as the “chemical scissor”  and Zn2+ (Zn-TDCOF-12) might be attributed to Zn2+ having stronger hydrolysis ability than Co2+ to bring more acidic reaction solvent. The increase of dangling bonds caused by post-modification of Co2+ is not obvious, which makes it difficult to achieve rational and effective design of dangling bonds for COF materials. In addition, in our previous work, it was revealed that Co2+ ions at the porphyrin centers of Co–COF were the critical sensing sites.31 Therefore, Co–COF is impossible to explore the structure–activity relationship of dangling bonds and gas sensing.Furthermore, we have considered whether other metal ions have a similar function to Zn Fig. S27. Compare Fig. S27 and S27†x was tested using a home-made system.45 Zn-TDCOF-12 was taken as an example to explore gas sensing performance in depth. Under dark conditions, the NO2 adsorption energy of Co (−1.5 eV) is 6 times higher than that of Zn (−0.25 eV), but the response of Zn-TDCOF-12 to 100 ppm NO2 is 4766, which is 1.8 times higher than that of Co–COF in our previous work,31 and it can't recover , which is lower than the air quality guideline (AQG) level (1 h and 104 ppb) from the World Health Organization (WHO) , indicating its good repeatability  were compared with each other. With the increment of treatment time, although the SBET of Zn-TDCOF-x is reduced, their NO2 sensitivity displays a Gaussian distribution with a maximum for Zn-TDCOF-12  (3)2 in TNPP has the same electron donor capability as –NH2 in TAPP to the porphyrin center, but produces a worse response to NO2 with a value of 31. These results suggest that –NH2 is the main active functional motif for sensing  is replaced by 1,4-phthalaldehyde (PA) Fig. S40.56 Diffe Fig. S41. Meanwhi Fig. S41 and S42†CH3, 62)  and S43† sensing . Therefo2. Zn–COF-366 shows a recoverable response to 100 ppm NO2 under dark conditions, suggesting that it has weak physisorption to NO2 and may be due to the interaction between Zn and NO2 through π-backbonding  and XPS (407.2 eV)   and S46†ive site . Furthern to NO2  and S47†2 sensing test of other porous materials with amine groups. Taking a representative MOF, NH2-UiO-66, for example, the response to NO2 was tested under similar conditions to Zn-TDCOF. NH2-UiO-66 showed neglectable response to 100 ppm NO2  highly conjugated porphyrin improves the charge transfer ability of Zn-TDCOF; (2) conjugated 2D layered structure provides electron transport channels; (3) thin nanosheet morphology exposes more gas accessible active sites.To explain the sensing function of Zn-TDCOF, we performed a NO Fig. S48, which mx possesses a large number of dangling bonds as gas sensing functional motifs 46 and promotes its desorption from Zn-TDCOF-x, which recovers the current to the original  Zn-2+ into the framework of TDCOF nanosheets, which elongates the target imine bond and activated it to bring about the rational fracture of target bonds in a hydrolyzation reaction to create dangling bonds. The number of dangling bonds could be well-modulated by controlling the time for treating TDCOF with Zn2+ solution. The critical roles of Zn2+, protonic solvent, lattice water of zinc salt, and treatment time played in modulating dangling bonds were also systematically revealed. Compared with pristine TDCOF, Zn-TDCOF-x possesses a large number of exposed –NH2 dangling groups as chemically active sites and better mass transport avenue. As a result, Zn-TDCOF-12 shows one of the highest sensitivities in all reported NO2 sensing materials working under visible light and room temperature conditions. Zn-TDCOF-x also shows unique selectivity to NO2 among 9 typical interference gases and excellent long-term stability for up to 35 days. This work provides a feasible strategy to rationally modulate the dangling bond for COF materials.To rationally design dangling bonds on COF materials, a facile metal coordination induced “chemical scissor” strategy is proposed. This is demonstrated by the post-metallization of Zn2·2H2O (AR), acetic acid , ethanol  and tetrahydrofuran  were purchased from Sinopharm Chemical Reagent Co., Ltd. 1,2-Dichlorobenzene (AR) was obtained from Shanghai Lingfeng Development Co., Ltd.All solvents and reagents obtained from commercial sources were used without further purification. 5,10,15,20-Tetrakis(4-aminophenyl)porphyrin  was purchased from Shanghai Kylpharma. 2,6-Diformylpyridine  and 1,4-phthalaldehyde  were purchased from Shanghai Aladdin. Zn(OAc)λ = 1.54060 Å). Scanning electron microscopy  and transmission electron microscopy  were performed to investigate the morphology of the samples. N2 adsorption tests were carried out using a BELSORP MAX automatic volumetric gas adsorption analyser and a sample was pretreated at 120 °C for 24 h. The FT-IR spectra were recorded from KBr pellets in the range 4000–400 cm−1 on a Nicolet 170 SXFT-IR spectrometer. X-ray photoelectron spectroscopy (XPS) measurements were performed on an American Thermo-VG Scientific ESCALAB 250 Xi XPS system with Al Kα radiation as the exciting source. A xenon arc lamp (PLS-SXE300D) with a light filter (420–760 nm) was utilized as an irradiation source. The test of chemical adsorption of CO2 was carried out through a thermal gravimetric analyzer (TGA) on a MEMS cantilever .Powder X-ray diffraction (PXRD) patterns of samples were obtained on a Rigaku SmartLab (Japan) with Cu Kα radiation , DFP , EtOH (0.1 mL), 1,2-dichlorobenzene (0.9 mL) and AcOH  were mixed in a Pyrex tube . After sonication for about 25 min, the tube was flash-frozen at 77 K (liquid N2 bath) and degassed to achieve an internal pressure of ∼100 mTorr after three freeze–pump–thaw cycles. After the temperature recovered to room temperature, the mixture was heated in an oven at 120 °C for 5 days. After cooling to room temperature, the obtained product was filtered and transferred to a Soxhlet extractor and washed with THF (24 h). After drying at 120 °C under vacuum for 24 h, TDCOF was obtained.The synthesis method of TDCOF follows previously reported procedures.x was carried out with a hydrothermal reaction by Zn metal post-modification based on TDCOF, respectively. Taking Zn-TDCOF-12 for example, Zn(OAc)2·4H2O (200 mg) was dissolved in 50 mL ethanol solution with sonication for 2 min in a 100 mL flask. The above prepared TDCOF (100 mg) was added to the clear solution and refluxed at 40 °C for 12 h. After cooling to room temperature, the obtained product was washed with water and ethanol each 3 times. After drying at 80 °C under vacuum for 12 h, Zn-TDCOF-12 was obtained.The synthesis of Zn-TDCOF-x  based on the reaction time. x stands for the treatment time for Zn metal post-modification with the unit of an hour.The synthesis process of Zn-TDCOF-6, 9 and 15 is similar to that of Zn-TDCOF-12 except that the reaction time was different , which is denoted as Zn-TDCOF-56 TAPP , PA , ethanol absolute (1.0 mL), mesitylene (1.0 mL) and acetic acid  were mixed in a Pyrex tube . The as-obtained COF-366 (100 mg) was added in Zn(OAc)2·2H2O (200 mg) based ethanol solution (50 mL) followed by sonication for 2 min. The suspension was refluxed at 40 °C for 12 h. After cooling to room temperature, the product was filtered and washed with water and ethanol each 3 times. After drying at 120 °C under vacuum for 12 h, Zn–COF-366 was obtained.Firstly, the synthesis method of COF-366 follows previously reported procedures.The data are available upon request.Y.-J. C. and G. X. conceived the idea. Y.-J. C., M. L., J. C. and X. H. designed the experiments, and collected and analyzed the data. Q.-H. L. accomplished the theoretical calculation. X.-L. Y. and G.-E. W. assisted with the experiments and characterization. Y.-J. C. and G. X. wrote the manuscript. All authors discussed the results and commented on the manuscript.There are no conflicts to declare.SC-014-D3SC00562C-s001


In this paper, nanosheet deformation during channel release has been investigated and discussed in Gate-All-Around (GAA) transistors. Structures with different source/drain size and stacked Si nanosheet lengths were designed and fabricated. The experiment of channel release showed that the stress caused serious deformation to suspended nanosheets. With the guidance of the experiment result, based on simulation studies using the COMSOL Multiphysics and Sentaurus tools, it is confirmed that the stress applied on the channel from source/drain plays an important role in nanosheet deformation during the fabrication process. The deformation of Si nanosheets would cause a serious degradation of the device performance due to an inability to control the work function of the metal gate. This study proposed that the uniformly stacked GAA nanosheets structure could be successfully demonstrated with suitable channel stress engineering provided by fitting S/D size and an appropriate channel length. The conclusions provide useful guidelines for future stacked GAA transistors’ design and fabrication. Today, the whole complementary metal oxide semiconductor (CMOS) community is looking for solutions to complete the International Technology Roadmap for Semiconductors (ITRS) roadmap requirements. Maintaining a higher drive current with low off-state current leakage and controlling irresistible short channel effects (SCEs) are the primary challenges that limit the further downscaling of CMOS devices ,2. Gate-In order to achieve a compatible fabrication approach with the mainstream FinFET process and improve the driving ability of the GAA device, several studies ,10 have For the stacked GAA NS transistor, the channel release process is one of the main challenges in device fabrication , where nIn this work, the systematic investigation about the impact of S/D compressive stress on the mechanical stability of Si nanosheets during the channel release process is demonstrated. In particular, through extensive experiments, it has been found for the first time that the stress applied on nanosheet channels determines the deformation, which has been well explained and confirmed by insightful simulation based on Sentaurus SProcess and COMSOL Multiphysics. 0.7Ge0.3) superlattices were epitaxially grown on bulk Si (100) substrate. Then, the superlattice structure was patterned and etched down to the Si substrate by Inductive Coupled Plasma (ICP) to form a channel region as well as the S/D region. Moreover, the Si0.7Ge0.3 sacrificial layers were selectively removed through etching solutions including 10% HF, 30% H2O2 and 99.8% CH3COOH (mixing and aging for 72 h) with volume ratios of 1:2:3 [2 and 10 nm TiN by Atomic Layer Deposition (ALD) were completed immediately afterwards.of 1:2:3 ,25,26,27Two categories of experiments were designed for this work to study the correlation of device structure and stacking channel integrity after channel release. The fabricated fixed S/D width and length are 1 µm and 0.5 µm, while two different nanosheet dimensions with fixed width (30 nm ) and difThe fabricated fixed nanosheet width Wch and length Lch are 30 nm and 100 nm, while two different S/D sizes with fixed width (1 µm) and different lengths of 2 µm and 0.5 µm were used.The red box in For experiment A, circled by the blue box in For a GAA device with 200 nm nanosheet length, as shown in For experiment B, circled by the red box in Compared to the GAA device with smaller S/D size in The experimental results clearly indicated that nanosheet length and S/D size are both the possible impact causing nanosheet deformation. In order to understand the impact of these key factors on the deformation of the Si nanosheet, insight TCAD simulations were demonstrated accordingly.0.7Ge0.3 is compressive stress  at the However, the Sentaurus TCAD tools cannot take the mechanical deformation in nanosheet into account, so we utilized the three-dimensional (3-D) numerical simulator COMSOL Multiphysics tool to study the mechanical displacement in GAA nanosheets by a finite element calculation approach because COMSOL includes a solid mechanics module. The simulation mesh size was defined as 1.5 nm. In addition, all simulations were performed under a steady-state condition.(1)Si nanosheets’ GAA structure as carried out in the COMSOL is exactly the same as in the experiment, including the same Si nanosheet dimension, same S/D dimension and same Ge component in S/D.(2)C11, C12 and C44, as shown:Especially, the dominant material parameter to determine the deformation of the Si nanosheet is Young’s modulus. Therefore, the setting of Young’s modulus of the material in COMSOL is completely consistent with the actual structure. Young’s modulus derived from the stiffness matrix is related to the stiffness factor describing the ability to resist deformation. Si and SiGe are both cubic crystal systems whose stiffness matrix is composed of three independent elastic constants, Moreover, setting the exact, precise structure dimensions and material parameters in COMSOL tools are vital to assure simulation consistency; the details are as shown below:C11, C12 and C44 of Si are separately 165.8 GPa, 63.9 GPa and 79.6 GPa. Similarly, elastic constants C11, C12 and C44 of Ge are separately 128.5 GPa, 48.3 GPa and 66.8 GPa. Therefore, the elastic constant of Si0.7Ge0.3 [x = 0.3.It is reported that the elastic constants 0.7Ge0.3  used in 0.7Ge0.3 into (5)–(8) to obtain Young’s modulus [0.7Ge0.3 were both put into material properties of the COMSOL simulation separately.Then, put the elastic constants of Si and Si modulus . FinallyCompressive stress, which is the most significant parameter in this mechanical displacement simulation, was applied to the SiGe S/D. After setting the material parameters, the compressive stress in fully strained S/D, −2 GPa, was put into the device in COMSOL the same as the structure in the experiment. Finally, the deformation of the suspended Si nanosheet was obtained in the COMSOL mechanical simulation. The process of deformation simulation is the result of the natural relaxation of stress −2 GPa during channel release. Therefore, for simulation in COMSOL, the input condition is the SiGe S/D compressive stress, and the simulation result is the deformation of the Si nanosheet. To verify the realism of the COMSOL simulation deformation, the stress distribution after fin etch was simulated in both COMSOL and Sentaurus TCAD, adopting the same SiGe S/D stress. The stress mappings are found to be very similar, so it can be guaranteed that the model of COMSOL simulated deformation is feasible.GAA nanosheets devices with different nanosheet lengths of 100 nm and 200 nm have been simulated. Additionally, a fixed S/D size  and nanosheet width of 30 nm were used. From the comparison of The S/D regions with varied length from 0.2 µm to 2.0 µm and a fixed width of 1 µm were used, while the same nanosheets width of 30 nm and length 100 nm were adopted. Similarly, according to the structural parameters of Experiment B, the compressive stress value −2 GPa was input into the GAA device with different S/D lengths in Comsol, and the corresponding deformation was obtained by COMSOL simulation, as shown in schematic The simulation results agreed excellently with the aforementioned experiment analysis and strongly verified that nanosheet length and stress-ZZ provided by S/D are both the key origins causing nanosheet deformation. Therefore, deliberating S/D stress engineering and adopting special process engineering to tackle displacement problems for different lengths of nanosheets during the device fabrication are vital to achieve uniform nanosheets structure. However, for extending to the realistic GAA device structure with epitaxial S/D, especially PMOS with SiGe S/D, because the main transport orientation in the GAA NS Nanosheet transistors changes from (110) to (100), which exhibits higher electron mobility but lower hole mobility, the channel stress engineering plays more important roles, especially for PMOS performance, when achieving N/P balance . Giving The Si nanosheet deformation will not only have a bad effect on the work function of the metal gate but will also cause stress loss in the channel, so in this work the impact factors of Si nanosheet deformation have been investigated and discussed based on both experiment and TCAD simulation results for the first time. Three-layer stacked GAA nanosheets devices under different strain conditions and Si nanosheet length have been designed and successfully fabricated. Furthermore, Sentaurus and Comsol simulations have been carried out to validate the impact of stress provided by S/D and Si nanosheets’ length on its deformation. The results of the simulation synchronized with experiments suggest that the two factors both play an important role in Si nanosheet deformation. This paper highlighted that deliberating strain engineering and employing suitable nanosheet dimensions in device fabrication are vital to achieve highly uniform nanosheets as well as uniform inter-channel space. Additionally, obtaining greater stress-ZZ in silicon nanosheets without affecting the subsequent steps of the HKMG could be of great concern in extremely scaled GAA nanosheets transistors study. The conclusion will be helpful for subsequent stacked GAA transistors fabrication.