N-hydroxysuccinimide reactions, and physisorption. In the literature, several detection methods are employed; however, the most common is electrochemical. The main reason for researchers to use this detection approach is because this method is simple, rapid and presents good sensitivity. These biosensors can be particularly useful in life sciences and medicine since in clinical practice, biosensors with high sensitivity and specificity can significantly enhance patient care, early diagnosis of diseases and pathogen detection. In this review, we will present the research conducted with antibodies, DNA molecules and, enzymes to develop biosensors that use graphene and its derivatives as scaffolds to produce effective biosensors able to detect and identify a variety of diseases, pathogens, and biomolecules linked to diseases.Graphene’s unique physical structure, as well as its chemical and electrical properties, make it ideal for use in sensor technologies. In the past years, novel sensing platforms have been proposed with pristine and modified graphene with nanoparticles and polymers. Several of these platforms were used to immobilize biomolecules, such as antibodies, DNA, and enzymes to create highly sensitive and selective biosensors. Strategies to attach these biomolecules onto the surface of graphene have been employed based on its chemical composition. These methods include covalent bonding, such as the coupling of the biomolecules via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and  Conventional sensing methods, such as lateral flow immunoassay, fluorescent microarray and electrochemical methods, polymerase chain reaction (PCR)-based methods, DNA microarrays, DNA sequencing technology, enzyme-linked immunosorbent assay (ELISA), among others –6 requirSensors in medicine and life sciences have been used to monitor vitals, diagnose patients, and improve the critical care of patients –10. Due Among the nanomaterials used for nano-sensor fabrication, graphene and graphene-based nanomaterials have been showing the most promise since they present an enhanced signal response in a variety of sensing applications –13. FurtIn general terms, sensors consist of two elements: a receptor and a transducer see Fig. . The recGraphene has been employed in the design of different biosensors of various transduction modes because of its large surface area, electrical conductivity, high electron transfer rate and capacity to immobilize different molecules . For insWhen using graphene nanomaterials for designing sensors, some aspects of the graphene properties affecting the detection limit of the target molecules need to be taken into consideration. For instance, different synthesis batches of graphene and derivatives, as well as different synthetic methods can lead to different properties and functionalities of the graphene-based nanomaterials in the biosensors. The orientation between the G, GO or rGO sheets and the bioreceptor can also directly affect the selectivity and sensitivity of the biosensors. Additionally, the number of layers, the functional groups and oxidation states of graphene and derivatives will cause differences in the sensing performance among the sensors and even impact the bonding between the transducer and bioreceptor. The amount of functional groups on the nanomaterials can also affect the interactions and the detection limit of the target molecule. In this context, it is often necessary to block any nonspecific adsorption sites on the nanomaterial to prevent unspecific binding of biomolecules instead of the target molecules. This can be accomplished by coating with blocking reagents such as bovine serum albumin (BSA) , casein,In this mini-review, we will briefly summarize recent developments on biosensor technology with graphene and graphene-based nanomaterials. More specifically, we will focus on antibody, DNA and enzyme-based biosensors with applications in life sciences as well as in clinical settings. We aim to present conceptual advances that have been made in the synthesis and applications of biosensors for clinical diagnosis and real-time molecular detection.2) groups that bind to the target molecule with high affinity [The analytical detection platforms that measure the specific conjugation reaction between antibody and antigen are called immunosensors. The biocompatibility and high-affinity binding of antibodies to antigens make this molecule attractive for use in several fields, particularly in diagnostics. The antibody (Ab) structure is made of four polypeptide chains with a characteristic “Y” shape Fig. . The chaaffinity , 27. ThiN-hydroxysuccinimide (NHS) (EDC/NHS) chemistry reaction, electrostatic bonding, or via 1-pyrenebutanoic acid succinimidyl ester (PASE) linker. The functionalization via EDC/NHS chemistry is the most popular and versatile method for producing biochemical conjugations. EDC is a water-soluble cross-linker agent, which allows direct bioconjugation between carboxyl and amine groups. In this reaction, the nucleophilic attack from the primary amine group from the antibody forms an amide bond with the carboxyl groups on the GO surface. This process can form conjugates between two different molecules with an amide group [The versatility of functional groups of the GO surface allows different strategies for Ab attachment. The Ab functionalization can be summarized in Table de group .Table 1OThe detection of the target molecules can be achieved through different methods . An overall comparison among all currently available sensing platforms indicates that the functionalization of graphene or graphene oxide with silver, gold or other metal nanoparticles and the antibody attachment via covalent bond, typically allows the lowest detection limits.Graphene-based nanomaterials on antibody biosensors offer a broad versatility regarding pathogen detection. Recently, several graphene-antibody biosensors with clinical applications have been developed for early detection of diseases Table . AntibodE. coli , 32 and E. coli . GO, on E. coli , rotavirE. coli  and cardE. coli . rGO has samples  but with samples , 32 and  samples . More adhimurium  and hepahimurium . Gold nahimurium  and for himurium , 43. Thehimurium  and alsohimurium . More cohimurium , polymerhimurium , 48 or chimurium  have beeThe early detection of these diseases with such sensors can aid in diagnosis, prevention, and management of the disease in ‘high-risk’ individuals, which in turn would contribute to better management and survival of patients. Many biosensors based on graphene nanomaterials have been proposed in the last few years for the diagnosis and real-time monitoring of the health status of patients. While the limitations of these types of sensors (binding affinity and irreversible antigen–antibody binding) are not fully rectified, the proposed biosensors exhibit very low detection limits (see Table Deoxyribonucleic acid (DNA) has a broad range of physical, chemical, and biological properties making this biomolecule highly suitable for biosensor technologies. Among the most critical properties of DNA for a biosensor is its flexibility, easy synthesis, facile chemistry to attach to diverse platforms, simple regeneration and high specificity due to unique sequences of nucleotides , 56. HowThe electrochemical sensor is based on measurements of the change in voltage, current, or impedance that can result from changes in electrochemical factors, such as electron loss, conductivity or capacitance changes, which are caused by the hybridization of DNA or the oxidation of adenine (A), thymine (T), cytosine (C) and guanine (G) of the DNA. The electrochemical signals produced by these biosensors can be detected using cyclic voltammetry (CV), differential pulse voltammetry (DPV) or electrochemical impedance spectroscopy (EIS) , 63. In The fluorescentDNA nanosensor is based on the hybridization of two single-stranded DNA (ssDNA). One ssDNA is labeled with a fluorescent dye, and the other is the complementary DNA corresponding to the target DNA. This method requires optical detection; therefore it takes advantage of the optical quenching property of graphene-based materials to enhance the visualization and detection of the target ssDNA . The immOne example of fluorescence biosensors that has been developed is the GO-based sensor. This sensor has been produced with multicolor DNA probes for detecting different sequence-specific DNA. This multiplex GO-based DNA sensor presents low background fluorescence and excellent emission signal from specific targets when the hybridization occurs . AnotherIn summary, the two methods seem efficient and present low detection limits. However, each technique has its advantages and disadvantages, which depends mainly on the ability of immobilization of the DNA in the graphene-based nanomaterials and the method of measurement. The electrochemical detection method takes into account the large surface area and conductivity of the nanomaterials. The detection is based on the types and numbers of bases present in the DNA, which would cause the changes in electrical potential for the measurement. Therefore, homogenous deposition of the probe on the graphene material is essential for accurate measurements. Also, the electrostatic potential and DNA length could affect the efficiency of the sensor. On the other hand, fluorescence detection can be performed in ssDNA or dsDNA regardless of the length of the DNA. This method is based on the quenching and optical ability of graphene-based nanomaterials. One of the main disadvantages of this method is that it can overestimate the fluorescence signal due to the high background fluorescence signal in some complex samples, such as serum samples. On the other hand, the fluorescent-labeled probe can lose its intensity (photobleach) over time. Results of graphene-based DNA biosensor studies have shown that there is still need for further investigations related to the mechanisms of interactions between the DNA probe or modified DNA probe and the graphene-based transducer to provide more reliable and accurate measurements. Such studies could overcome the current disadvantages of the method by lowering the detection limit of the current sensors.Enzymes deserve particular attention in biosensor design because they can be easily manipulated and have high stability. Furthermore, these molecules are involved in the metabolism of all organisms; they are reusable and highly selective catalysts that can discriminate between L and R enantiomers in different molecules. Enzymes can catalyze a large number of reactions with high specificity, efficiency, and selectivity, which are essential parameters in sensor design . HoweverAdvancements in enzyme-based biosensor research have resulted in improved stability while reducing enzymatic loss and enzyme response time . It has Several approaches have been developed to immobilize enzymes onto graphene surfaces to create enzyme-based biosensors. Some of the most common methods are sonication, mixing, ultrasound, and cyclic voltammetry. These methods allow the attachment of the enzymes via adsorption, covalent bonding, or physical entrapment. To date, the nonspecific binding of the enzyme to graphene via physical adsorption is the most common one , and the other is based on enzyme activity inhibition/moderation . Each of3O4 based substrate [Different molecules have been detected with enzyme-based nanosensors. The most commonly used model enzymes utilized for the development of these sensors are laccase and horseradish peroxidase (HRP) . These eubstrate . This hyWhile HRP and laccase have been vital in enzyme biosensor studies, other enzymes can be immobilized to create highly specific biosensors. For example, bilirubin oxidase was immobilized on GO-based surfaces , 116. SuIn this mini-review, we have reported recent studies describing graphene and graphene-related biosensors with possible applications in clinical settings and life sciences. We have shown results of the reported analytical performance of each sensor and indicated their use in the life sciences and medical fields. DNA, antibody, and enzyme-based biosensors have been presented in this study since each has its advantages and disadvantages. Overall, the type of sensor selected will depend on the type of application. For example, use of DNA in biosensing technology can be a cost-effective method for the rapid detection of microbes, viruses, or cancer markers. However, due to the vast variety of molecules present in the body, use of antibodies or enzymes in biosensors can be more effective in the detection or monitoring of certain diseases. For instance, antibodies can be used for the specific detection of viruses, such as the Zika virus, HIV, Influenza A virus, among others. Enzymes, on the other hand, have shown to be promising in detecting glucose levels with only small amounts of sample. Overall, the incorporation of graphene and graphene-based nanomaterials in biosensor technologies have shown great promise due to its high surface area, electrical conductivity, electron transfer rate, and its capacity to immobilize a variety of different biomolecules. The development of biosensors that are sensitive, stable, and specific to their target molecule and that can be processed rapidly are promising for use in clinical settings. However, to achieve uniform and reliable results and produce biosensors capable of being used in the medical field, many more studies need to be conducted examining the safety and reliability of the sensors.Although graphene is an excellent electrode material for sensing applications in the medical field, novel methods for well-controlled synthesis and processing of graphene need more attention and should be investigated in future studies. The current chemical strategies to modify the surface of graphene with biomolecules are effective in targeting specific analytes. Nevertheless, the sensing platform may be further refined to avoid the adsorption of unwanted molecules on graphene and improve the orientation of biomolecules on graphene platforms. Hence, a better understanding of the physics and chemistry at the surface of graphene and the interactions with biomolecules at the interface will play an important role in graphene-based nanosensors.Additionally, miniaturization and production of compact biosensors for diagnostic purposes is an emergent need in sensor technology since it requires development of reliable, reproducible, and cost-effective sensors with high accuracy, sensitivity, and specificity. Lowering the cost of some of these sensors is necessary to increase usability in remote areas for emergency uses. Furthermore, miniaturization of the sensors can allow rapid detection of virus and bacterial pathogens, as well as use in self-monitoring biological implants to detect serious health conditions. The aforementioned applications in the life sciences will serve to protect lives and improve people’s health. However, considerable work must still be done to ensure, guarantee, and corroborate the biocompatibility and non-toxicity of graphene-based nanomaterials such that their long-term use does not pose any health risk.


The obtained ITO nanostructure exhibited a unique architecture, with uniformly dispersed 25–35 nm size ITO nanoparticles, containing only the crystallized In2O3 phase. The synthesized ITO nanoparticles–graphene hybrid exhibited very good and reproducible optical transparency in the visible range (more than 85%) and a 28.2% improvement in electrical conductivity relative to graphene synthesized by chemical vapor deposition. It was observed that the ITO nanoparticles affect the position of the Raman signal of graphene, in which the D, G, and 2D peaks were redshifted by 5.65, 5.69, and 9.74 cm−1, respectively, and the annealing conditions had no significant effect on the Raman signatures of graphene.The combination of graphene with conductive nanoparticles, forming graphene–nanoparticle hybrid materials, offers a number of excellent properties for advanced engineering applications. A novel and simple method was developed to deposit 10 wt% tin-doped indium tin oxide (ITO) nanoparticles on graphene. The method involved a combination of a solution-based environmentally friendly electroless deposition approach and subsequent vacuum annealing. A stable organic-free solution of ITO was prepared from economical salts of In(NO A green, simple, and novel approach was used for hybridization of chemical vapor deposition (CVD) graphene with 10 wt% tin-doped ITO nanoparticles.A unique architecture with monodisperse 23–35 nm ITO nanoparticles over graphene was constructed to form a stable organic-free solution of ITO.High improvements on optoelectrical properties with 28.2% in electrical conductivity relative to individual CVD graphene and more than 85% optical transmittance in the visible range were achieved.sp2 honeycomb structure and has attracted attention since it was conclusively isolated from graphite in 2004 via an exfoliation method [Graphene is an ideal two-dimensional 2D) carbon allotrope with an n method –7. OwingD carbon n method –13.A range of approaches have been attempted, and various theoretical studies have been performed recently to ensure the real-world application of graphene with a variety of advantages, rather than using graphene alone, such as multilayer graphene sheets that can form hybrid composites with other conductive materials and decoration of graphene with metal and metal oxide nanoparticles –20. The Indium tin oxide or tin-doped indium oxide (ITO) is recognized as a viable semiconducting metal oxide with high conductivity, chemical stability, good optical transparency, and excellent substrate adherence, making it a prime candidate in most advanced electronic applications , 33. TheIn this study, we present a novel, simple, and versatile method for the deposition of ITO nanoparticles on graphene grown by chemical vapor deposition (CVD) method through a combination of a solution-based electroless deposition method and subsequent annealing. The solution used as the ITO source was prepared using an environmentally friendly aqueous sol–gel and the concentration of Sn was adjusted to 10 wt% in the final ITO nanoparticles.3·xH2O  and SnCl4  as initial materials. The stoichiometry of In(NO)3·xH2O was determined by thermogravimetric analysis, prior to mixing the materials, and hydration number was obtained as one. The materials were mixed using the appropriate stoichiometry as follows to obtain Sn 10 wt% for the final ITO solution. 3.876 g of In(NO)3·xH2O and 0.648 g (291.1 μL) of SnCl4 were mixed in 15 mL of deionized (DI) water, and the resultant solution was refluxed at 40 °C for 2 h. The obtained sol was aged for 48 h to achieve gelation before application.Aqueous ITO sol–gel was synthesized using In(NO2) and washed ultrasonically with acetone, isopropanol, and DI water, and dried using N2 gas flow. The cleaned Cu foil was loaded in the CVD chamber and heated to 1000 °C. 99.999% pure H2 gas was introduced to the chamber at 600 °C under a flow rate of 15 sccm, and the chamber pressure was maintained at 0.15 ± 0.01 Torr. Cu strips were annealed at 1000 °C for 30 min prior to introducing CH4. High-quality pure CH4 gas was supplied to the chamber with a 30 sccm flow rate along with a continuous supply of H2 gas, and the chamber pressure was maintained at 0.5 ± 0.1 Torr. The supply of both gases was stopped after 10 min of CH4 gas supply, after which the heater system was turned off, and the chamber system was cooled to room temperature /Si substrates using a poly(methyl methacrylate) (PMMA)-based indirect transfer method as follows: PMMA solution was prepared by mixing 4.5 g of PMMA ((C5O2H8)n, average Mw ~ 120,000, Aldrich) with 41 mL of monochlorobenzene  and stirred at 80 °C for 1 h to obtain a clear solution. PMMA was coated on the samples using a spin coater at 3000 rpm for 30 s and heated at 60 °C for 10 min. The rear sides of the PMMA-coated samples were dipped in the ITO etchant (LCE-12 K) for 1 min, followed by rinsing with DI water and in a metal etchant for 5 min, then rinsing with DI water to remove the dried ITO solution and graphene on the rear side of the Cu strips. The samples were transferred to the 50% diluted metal etchant solution  for 1 h to completely remove the Cu foil. The Cu-removed samples were transferred to HCl 10% solution, held for 5 min to remove contaminants from samples, and then transferred to DI water for 10 min to remove any residuals. The SiO2/Si (target substrate) was chemically and ultrasonically washed with acetone (5 min), isopropanol (5 min), and DI water (10 min), and dried using N2 gas flow. The well-cleaned samples were then transferred to SiO2/Si substrates. The PMMA layer was removed from the samples using acetone, 2-iso propanol, and DI water, which were then dried under N2 gas flow. Finally, the samples were annealed at 450 °C for 1 h under vacuum (0.15 Torr) to obtain a crystalline ITO nanostructure on the graphene. A SiO2 (300 ± 5 nm)/Si substrate was used as a standard reference substrate for the Raman characterization of graphene  for crystallization analysis. Detailed information about the chemical and elemental composition of ITO nanoparticle-decorated graphene was determined by X-ray photoelectron spectroscopy  and energy-dispersive X-ray (EDX) spectroscopy coupled with field-emission scanning electron microscopy . Raman spectra  were recorded using a 532-nm excitation laser from 1000 to 3000 cm−1. The microstructure of the ITO nanoparticle-decorated graphene was observed with an optical microscope  and FE-SEM.X-ray diffraction  was conducted with a monochromatic Cu anode  center, is the main Raman characteristic feature, whereas the 2D band is a second-order Raman characteristic feature originating from the double-resonance scattering process near the K or K′ point for all sp2 carbons [I2D/IG) was obtained as 2.09. Furthermore, the peak position, shape of the peaks, and I2D/IG ratio can be used to represent the number of layers in graphene. As shown by the red line in Fig. −1 represents the existence of monolayer graphene. This nature of the single Lorentzian peak is evident in the monolayer graphene, because only one Raman scattering cycle is excited near the K and K′ points in the BZ, revealing the single π electron valence band and π* conduction band structure [−1 with a determined D-to-G intensity ratio (ID/IG) of 0.121, indicating a small number of intrinsic defects in the CVD-synthesized graphene.Figure  carbons . The inttructure . A low-iID/IG demonstrate that CVD-synthesized graphene has a high-quality monolayer nature.The high intensity of the 2D band with respect to the G band, the FWHM of the 2D band, and the low intensity of the D band with very low The morphologies of the as-prepared graphene on Cu and air-dried graphene on Cu after 1-min immersion in ITO solution are shown in Fig. 2/Si before and after annealing at 450 °C for 1 h under vacuum is shown in Fig. Ea, representing the strength of the interaction between the adsorbed particle and graphene) and diffusion barriers (ΔE) are the key kinetic barriers controlling the growth morphology of nanoparticles on graphene, and the adsorbed nanoparticle transport process is governed by the surface diffusivity, obeying the Arrhenius law [E for the adsorbed particle on graphene because ΔE represents the rate at which the adsorbed particle can contact the nearest preexisting particle island before being attracted by other adsorbed particles to form a new particle island. As In is the main element in ITO, with a high Ea  and low ΔE , it plays the main role in the adsorption and growth of nanoparticles on graphene, because much lower ΔE for In on graphene tends to produce a much lower density of nanoparticles with a much higher particle size [2/Si can be observed in the optical microscopy image  as shown in Fig. As shown in Fig. nius law , 40. Thecle size . Althougcle size –43. Ther2O3 was present in the synthesized ITO nanoparticles on graphene [2/Si substrate. Table An XRD pattern of the ITO nanoparticle-decorated graphene, as shown in Fig. graphene , 33, 44.graphene , 46. The3/2 and In3d5/2 peaks were observed at 452.1 and 444.31 eV, respectively, as shown in the narrow-scan XPS spectra of In3d in Fig. 5/2 shows a 0.71 ± 0.2 eV chemical shift from the position corresponding to In3d5/2 of metallic In (443.6 ± 0.2 eV). Sn3d3/2 and Sn3d5/2 peaks were observed at 494.82 and 486.83 eV, respectively, as shown in the narrow-scan XPS spectra of Sn3d in Fig. 5/2 shows a 2.33 ± 0.2 eV chemical shift from the position corresponding to Sn3d5/2 of metallic Sn (484.5 ± 0.2 eV). The chemical shift to a higher binding energy of both peaks indicated that the ITO nanoparticles deposited on graphene were free of metallic compounds, and that only the oxide forms of In and Sn were present [iv to Snii occurred during the synthesis of the ITO solution and annealing, because the electrical conductivity of ITO decreased with the reduction of Sniv to Snii [2− lattice ions in ITO have two possible locations in the lattice, namely the oxygen-deficient and nondeficient regions [sp2 bonding of graphene, whereas the high-binding-energy peak located at approximately 285.94 eV corresponds to sp3 C–C bonding. This sp3 C–C bonding carbon was mainly due to contamination [sp3 C–C bonding.As depicted in Fig.  present –48. The  to Snii . An O1 smination , 50. Thesp3 bonds and vacancies [−1, respectively, with a small D peak at 1349.68 cm−1. However, the G and 2D peaks of graphene after vacuum annealing at 450 °C for 1 h revealed small blueshifts of 3.985 and 4.155 cm−1, respectively, as shown by the red curves of Fig. The crystallization of amorphous ITO nanoparticles starts at 160–180 °C. However, above 400 °C, annealing is required to complete crystallization with high electrical performance , 52. It acancies . G and 22O and O2 after exposure to atmospheric air [K to K′ intervalley, a D′ peak that scatters from the K to K intervalley, and a low-intensity D + G combination scattering peak were observed at 1342.00, 1621.08, and 2933.42 cm−1, respectively, as shown in the blue curve in Fig. −1, respectively, after ITO nanoparticle deposition, as shown by the blue curve in Fig. n-type/p-type doping in graphene introduced a red/blueshift in the Raman spectrum, and the magnitude of the shift and relative 2D band intensity with respect to undoped graphene depended on the dopant concentration [The blueshift of the G and 2D bands was due to the hole-doping effect, because other adsorbates on CVD graphene were much more reduced during annealing, introducing adsorption sites on graphene for atmospheric molecules such as Heric air , 54. Theeric air . Three sntration . Graphenntration , 57. Thentration .ID/IG and I2D/IG variation with different conditions of graphene. Graphene after annealing at 450 °C for 1 h revealed ID/IG and I2D/IG values of 0.13 and 2.01, respectively, which are practically identical to those for the CVD graphene ; this demonstrated that vacuum annealing at 450 °C for 1 h had no significant effect on the structural changes and creation of new defects in graphene. However, after the deposition of the ITO nanoparticles on graphene, an increment in ID/IG of up to 1.254 and the reduction in I2D/IG to 1.277 were revealed, indicating that disorder-induced structural changes of graphene occur as the result of the introduction of ITO nanoparticles over graphene.Figure V–I) characteristics of graphene (dotted line), the ITO nanoparticle-deposited graphene (continuous line) at room temperature, and a schematic diagram of the prepared samples. The plot illustrates the dependence of the current, through the 500 µm length of the sample, on voltage, applied across the sample by using Cu electrodes. The reciprocal gradients of the graphs represent the corresponding resistance (R) between the two conductors, whereas the high slope of the graph indicates a lower resistance. The high slope of the V–I curve according to the ITO nanoparticles-deposited graphene implied a lower resistance than that of graphene. The mean sheet resistance of the ITO nanoparticle-decorated graphene was approximately 522.21 Ω sq−1 , obtained using the four-point probe method, where the decrease in sheet resistance was approximately 28.2% relative to CVD graphene, with a mean sheet resistance of 727.43 Ω sq−1 (SD = 15.54 Ω sq−1). The ITO nanoparticles introduce electron doping to graphene, which improves the surface electron density of graphene, because the conductivity is proportional to the carrier concentration, resulting in a lower sheet resistance from the ITO nanoparticle-deposited graphene. However, the conductivity of the ITO nanoparticle-deposited graphene was not as high as that of the continuous ITO film, owing to the discontinuous nature of the ITO nanoparticles over graphene. Figure Figure The density of ITO nanoparticles can affect electrical and optical properties of the hybrid materials. The nanoparticle density is directly proportional to optical density, and according to the Beer–Lambert law of absorbance, the density of nanoparticles can be represented by the optical density owing to the constant absorptivity coefficient and path length for each ITO/graphene hybrid sample , 60. Fig3)3•H2O and SnCl4. It was observed that a unique structure with 25–35 nm evenly dispersed crystallized ITO nanoparticles was formed on the graphene. The functional properties of the ITO nanoparticles–graphene hybrid transparent conducting electrode were demonstrated to be good and reproducible with a mean sheet resistance of 522.21 Ω sq−1, representing an improvement of 28.2% relative to that of the CVD graphene, and showed more than 85% light transmittance in the visible region. The annealing conditions did not significantly affect the Raman signals. However, the ITO nanoparticles induced the redshifting of the entire Raman signatures, in which D, G, and 2D peaks were redshifted by 5.65, 5.69, and 9.74 cm−1, respectively. The unique architecture of the ITO nanoparticles on graphene with a high surface area, enhanced electrical conductivity, and good optical properties in the visible range renders such hybrids suitable for optoelectronic and electrocatalytic applications.In this study, a novel, simple, and versatile method was proposed to deposit ITO nanoparticles on graphene. This method involved a combination of an environmentally friendly solution-based electroless deposition approach and subsequent vacuum annealing. Graphene was grown by the CVD method, and an ITO solution was synthesized by the organic-additive-free aqueous sol–gel method with economical salts of In(NO


The processes that result in progression of idiopathic pulmonary fibrosis (IPF) remain enigmatic. Moreover, the course of this disease can be highly variable and difficult to accurately predict. We hypothesized analyses of body mass index (BMI), a simple, routine clinical measure, may also have prognostic value in these patients, and might provide mechanistic insights. We investigated the associations of BMI changes with outcome, plasma adipokines, and adaptive immune activation among IPF patients.Data were analyzed in an IPF discovery cohort (n = 131) from the University of Pittsburgh, and findings confirmed in patients from the University of Alabama at Birmingham (n = 148). Plasma adipokines were measured by ELISA and T-cell phenotypes determined by flow cytometry.per se. BMI decrements were significantly associated with increased proportions of circulating end-differentiated (CD28null) CD4 T-cells (CD28%), a validated marker of repetitive T-cell activation and IPF prognoses.Transplant-free one-year survivals in subjects with the greatest rates of BMI decrements, as percentages of initial BMI (>0.68%/month), were worse than among those with more stable BMI in both discovery  and replication cohorts , when adjusted for age, baseline BMI, and pulmonary function. BMI decrements >0.68%/month were also associated with greater mortality after later lung transplantations . Circulating leptin and adiponectin levels correlated with BMI, but neither adipokine was prognostic IPF patients with greatest BMI decrements had worse outcomes, and this effect persisted after lung transplantation. Weight loss in these patients is a harbinger of poor prognoses, and may reflect an underlying systemic process, such as adaptive immune activation. The median survival of patients with idiopathic pulmonary fibrosis (IPF) is three-to-four years, but the courses of individuals with this lung disease are highly variable . An accuBody mass index (BMI) is routinely assessed in clinic practice, and is available in any facility that can measure patient heights and weights. Associations between BMI and prognoses have been reported among patients with chronic obstructive pulmonary disease (COPD) , 12, andper se.We have noted several anecdotal examples in our clinical practices wherein unexplained weight loss in patients with IPF seemed to portend poor prognoses. Consequently, we conducted analyses here to systematically test the hypothesis that dynamic changes of BMI may be associated with decreased survival among IPF patients. We postulated too that BMI reductions in this population might be related to an underlying systemic process(es) and not merely a simple, direct correlate of pulmonary physiology Clinical information about patients with ≥2 BMI measures between May 2000 and June 2014 was abstracted from prospectively recorded research registries at the University of Pittsburgh Medical Center (UPMC) and the University of Alabama at Birmingham (UAB). All subjects fulfilled IPF consensus criteria /BMIfirst) x 100. Rates of relative changes were calculated by dividing %BMIdelta by the interval (in months) during which these changes occurred .BMI , and telephone interviews.The primary endpoint of the study was one-year transplant-free survival (TFS), defined as the interval (for up to 12 months) after BMIvs. the remaining 75% who had lesser BMI reductions. The cut off value distinguishing these two categories was 0.68%/month in the discovery cohort and this value was applied to similarly dichotomize subjects in the validation cohort, and those who underwent lung transplantation.To perform survival analyses, we dichotomized discovery cohort subjects into the quartile with the greatest rates of weight loss Leptin and adiponectin were measured in plasma specimens by ELISA  according to the manufacturer's instructions.Peripheral blood mononuclear cells (PBMNC) were isolated from phlebotomy specimens by density gradient centrifugation . CD4 T-cLCO, over the same interval as the measured BMI decrement, as categorical variables. These physiological variables have often been associated with survival in IPF  with corresponding BMIdelta  and BMIlast . There were no significant associations of longitudinal changes in adiponectin levels with TFS .Cross-sectional adiponectin levels did not correlate with either BMIBMIdelta . Adiponefirst in 120 discovery cohort subjects. Survival analyses confirmed low [abnormal] CD28% was associated with decreased one-year TFS compared to subjects with normal CD28% , whCD28% were significantly reduced  in the IPF subjects who subsequently had the greatest BMI decrements .These data show that BMI decrements among IPF patients are associated with increased risks of transplantation and/or death. This relationship was evident in analyses of BMI changes as percentages of initial values, and with BMI changes as functions of time. Moreover, these findings were very similar in two distinct cohorts  and indeWeight loss is a harbinger of poor outcomes in several chronic conditions including COPD, rheumatoid arthritis, congestive heart failure, coronary artery disease, asthma and bronchiectasis , 26, 27 In distinction to these reports, however, we explored additional characteristics of BMI decrements in IPF. A novel observation of the present study is the effect of pre-transplant BMI decrements on IPF mortality after lung transplantations . This finull effector-memory T-cells are a specific consequence of repeated antigen receptor activation by conventional peptide epitopes and are not simply due to nonspecific global inflammation [.Accumulations of CD28ammation , 24, 28.ammation , 29–35. ammation .Adipokines such as leptin and adiponectin are proteins secreted predominantly by adipocytes that can modulate body weight via their effects on metabolic regulation . Adiponedelta for clinical use, and to attempt a rigorous comparison with other prognostic indices was beyond the intent and scope of this study. Instead, this analysis was prompted by clinical observations that led us to hypothesize BMIdelta reductions may be a significant, if under-appreciated, portent of poor outcomes in IPF patients. Moreover, after having found our hypothesis was plausible, incremental studies were performed to explore underlying mechanisms that might account for the BMIdelta and, more importantly, possibly contribute to disease progression.The present report describes our initial investigation into the association of BMI changes with outcomes among IPF patients with IPF. It is not a definitive validation of the BMIdelta, perhaps in addition to other demographic and physiological parameters [This report has limitations. By necessity it is a retrospective analysis, and has the inherent flaws of these study types. Cryptic biases are possible, such as over-representations of more healthy survivors, due to premature subject drop out of the most ill patients prior to their second BMI measures. Although the aggregate subject number here is greater than in analogous reports , 18, therameters , 25, in delta to progression and outcome of this lung disease. The present data also indicate changes of BMI per se, or in combinations with other measures, could eventually be a useful clinical tool to identify IPF patients with increased risks of near-term mortality.IPF patients with more stable BMI had longer transplant-free survival than patients with greater weight decrements in both IPF study cohorts. These findings could be an impetus for further research to more fully determine causes of the weight loss in IPF patients and better understand the pathological mechanism(s) that link BMIS1 Data(XLSX)Click here for additional data file.


Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.  Active  capture  and so o3 and nano-SiO2, is an ideal approach to dramatically improve the thermal stability, mechanical property and compactness of microcapsules [The research contents of microcapsules can be divided into two aspects: fabrication of novel functional microcapsules and characterization properties of functional microcapsules . For thecapsules . 2·g−1 [−1·K−1 and the largest conductivity of 6 × 105 S·m−1. Furthermore, graphene possesses excellent mechanical properties, such as a 130 GPa tensile strength and a 1.0 TPa Young’s modulus [Publications and patents of graphene research are explosively growing and arousing worldwide interest due to graphene’s peculiar physical characteristics. Graphene has a unique and peculiar structure and properties, which are different from other well-known materials. It is the thinnest two-dimensional 2D) carbon material with a single layer of carbon atoms and a specific surface area of 2600 m2·g−1 . Also, i modulus . Due to  modulus . Initial modulus , thermal modulus , drug de modulus  and phot modulus . FunctioD carbon  modulus . These m modulus .Although graphene has been considered as an additive to enhance the physical function of microcapsule product, it is still hard for it to deposit on microcapsule shells because its monolayer carbon atom structure does not have any chemical reaction with the organic molecule compared to graphene oxide. In-situ polymerization  is a normal preparation method for microcapsules with graphene or graphene oxide ,9. In deInspired by the broad application prospects of graphene microcapsules, the aim of this work was to prepared microcapsules with self-assembly graphene in shells. In view of chemical engineering, the effect of the pH values of polymerization in emulsion was systematically investigated on the microstructure and characteristics of microcapsule samples. The detail of self-assembly polymerization process was observed under pH values between of 3 to 7. Microstructure and properties of microcapsule samples were significantly affected by the pH values. In this work, the physicochemical microstructure of microcapsules was investigated to ensure the graphene content was adequate. The thermal stability and thermal conductivity of microcapsules were measured. The mechanical property of single microcapsule was tested by nanoindentation technology. The compactability of microcapsules was evaluated by a penetration method. Properties information is helpful to understand the graphene self-assembly process of influencing by pH values. Furthermore, these results can be used to guide the production of graphene functional microcapsules in chemical engineering.3, 4.24 Pa·s, Tianjin Sinogo. Co., Ltd., Tianjin, China). Prepolymer hexamethoxymethylmelamine (HMMM) was used as the polymeric shell material and was supplied by Tianjin Sinogo. Co., Ltd. . A copolymer of styrene maleic anhydride (SMA) was purchased as a dispersant . Other chemicals are chemically pure reagents.Graphene was a commercial product supplied by Tuling Co., Ltd. . Paraffin was used as the core material (0.905 g/cm−1 stirring speed. This dropwise addition method can help to achieve a perfect shell structure of microcapsules with a relatively low reaction rate [−1. (3) pH value of above solution was adjusted to 3–7 by a 1.0 wt.% ethylic acid dropwisely. The temperature of solution was raised from 40 °C to 80 °C with a speed of 2 °C·min−1. Temperature was naturally cooled to room temperature after a 3 h cross-linking polymerization of HMMM. (4) Through filtration, cleaning and drying, the microcapsule product was finally obtained. The graphene microcapsule samples were fabricated by a self-assembly method with the following four steps ,9: (1) SThe formation details of microcapsules in emulsion was observed by a biological microscope . The dried microcapsules were adhered on a double-side adhesive tape without cracking the shells. The surface morphologies were observed by using a scanning electron microscope  at an accelerated voltage of 20 kV. The state of graphene in shells was observed by a transmission electron microscope . Laser particle size analyzer  was utilized to measure the size distribution of microcapsules. In order to measure the shell thickness of shells, a gelatin composite sample was made with microcapsules (10.0 g) dispersing in it. Cross-section slides of the composite were obtained using an ultramicrotome . Shell thickness could be easily measured under a microscope. The average value of fifty thickness data was calculated as the value of the shell thickness of the certain microcapsule sample.−1. An energy dispersive spectrometer  was applied to determined the elements ratios of C, N, and O in microcapsule shells. The chemical functional groups of shell material were analyzed using a FT-IR  spectra in absorption modes recorded among the range of 400–4000 cm−1 nitrogen (N2) with a scanning rate of 5 °C·min−1.The thermal stability characterization of microcapsule samples was analyzed by a thermogravimetic analysis  in a flow of 40 mL·minΦ is the heat, λ is thermal conductivity, A is the area of powder, h is the thickness of powder, and T1 and T2 are temperatures of upper surface to the lower surface. The thermal conductivity of microcapsule powder was measured by a thermal conductivity tester  referencing ASTM E-1530 Standard. Microcapsule powder was spread between the two polished surfaces held. A pressure was forced on the surfaces. Heat flowed from the upper surface to the lower surface through the powder sample establishing an axial temperature gradient in the stack. The temperature difference was measured based on the heat output from the heat flow transducer at a thermal equilibrium. The heat data and powder thickness were used to calculate the thermal conductivity according to Equation (1)Thermal transmission phenomena were observed by using an infrared thermograph . A microcapsule sample (5.0 g) was put on a constant temperature heating plate with temperature of 100 °C. Thermal images were taken every 5 s during 50 s. The heat conduction law was analyzed by comparing these infrared thermographs. ® XP  cone tip (3 μm radius) was out on a single microcapsule with a pressure as illustrated in A Nano IndenterP) of the dispersing medium is measured and converted into the concentration of paraffin using a calibration curve,RP is the residual weight of paraffin still in microcapsules, P0 is the P value of all encapsulated paraffin in ethyl alcohol and Pt is the P value of encapsulated paraffin in ethyl alcohol at a point of permeation time (t). A qualitative analysis was carried out to compare the resistance penetration capability of different microcapsule shells with graphene [Penetration capability of paraffin out of microcapsules was evaluated using a UV visible spectrophotometer . In this work, ethyl alcohol was applied as a good extraction solvent, which easily extracted the core material of paraffin. The relationship between the penetration time and the residual weight of paraffin was plotted based on the transmittance of UV light. The optical density  ratio is 1/2 and the graphene/HMMM ratio is 5.0% as listed in Four parameters usually are characterized for a self-assembled microcapsule product, including the average size, shell thickness, shell microstructure and shell strength . These cMore microstructure details of shells can be observed from the SEM morphologies of microcapsule samples. Microcapsules (M-0) have a global shape without rupture a, which Beside the investigation of the surface morphology of microcapsules, it is necessary to prove the core-shell structure of a microcapsule product. At the same time, the geometry of the core-shell structure including the shell thickness and average size should be tested systemically. Both are very important for the physical properties of microcapsules. In this study, the effect of addition of graphene on the geometry also needs to be considered. −1, the M-0 sample has an average thickness of 1.01 μm as shown in 3/organic shells of microcapsules [It is hard to measure the shell thickness of a microcapsule because it has a global shape. Another reason is that the microcapsules do not own the same shell thickness fabricated by the hybrid method. In this work, we applied an simple method to successfully measure the shell thickness using an ultramicrotome technology . Figure capsules . With th−1 emulsion stirring speed. Nearly all microcapsules have a particle size in the range of 3–20 μm. Usually, the average diameter of microcapsules is determined by the core material emulsion stirring speed and it is not greatly influenced by their shell thickness [Besides the shell thickness, the effect of pH value on the average size of microcapsules also been investigated in this work. It is well known that the microcapsule particles have a normal distribution prepared by an emulsion polymerization method . Figure 3) under acidic condition. Therefore, the performance of the microcapsule shells is determined by the polymerization of HMMM molecules. The polymerization of HMMM molecules is also determined by the reaction pH value. The FT-IR spectra are used to analyze the chemical structure of microcapsule shells. −1, 1350 cm−1, 991 cm−1, 831 cm−1. The absorption peak at 2920 cm−1 is attributed to C–H telescopic vibration of methylene. It is difficult to find the absorption peak of the methyl group to prove that the polymerization of HMMM resin is a sufficient chemical reaction. The absorption peaks at 991 cm−1 and 1350 cm−1 are assigned to the C–N telescopic vibration and C–O–C telescopic vibration in the HMMM resin. No characteristic peak of graphene can be found in the FT-IR curves. The existence of graphene does not affect the characteristic peaks of cross-linked HMMM for all microcapsule samples. The above phenomenon indicates that the pH value does not affect the chemical structure of the microcapsule shell and the graphene is only composited with the HMMM rein by physical cross-linkage.EDS results were applied to evaluate the deposition contents of graphene in shells. Thermal stability of microcapsules is one of the most important issues in determining the performance of microcapsules. It has been found that the addition of graphene can greatly enhance the thermal stability of the microcapsules. More graphene deposition on shells can lead to a higher thermal stability of microcapsules . The depThe morphology of the microcapsules at high temperatures also can reflect the capability of microcapsules resisting heat. −1. The significant increase can be discovered from M-4 to M-5. This is due to the increase in the deposition of graphene on the surface of the microcapsule shell. Thermal conductivity starts to increase when the pH values of microcapsules preparation increase from 3 to 5. Thermal conductivity decreases when the pH value of the microcapsule preparation exceeds 5. This phenomenon indicates that the content of graphene on the microcapsule shell is normally distributed with the pH value of the microcapsule preparation. This is consistent with the previous results.In previous studies, the greater the deposition of graphene on the shell of the microcapsule samples, the higher the thermal conductivity of the microcapsule samples . Therefo1-a10), M-3 (b1-b10), M-4 (c1-c10), and M-5 (d1-d10). Sample M-0 has the slowest temperature increasing speed under a constant temperature (100 °C). Its temperature changes from 25.9 °C to 38.3 °C in 50 s. Microcapsules without graphene have a low sensitive to temperature because of poor thermal conductivity of HMMM resin. It can be observed that the thermal conductivity of the microcapsules is improved with the addition of graphene. The temperature of sample M-5 is raised rapidly from 26.1 °C to 69.1 °C in 50 s. This is attributed to the maximum deposition of graphene on the microcapsule shell under the preparation condition of pH = 5. Another approach was applied to visually observe the thermal conductive character using a constant temperature heating plate with a temperature of 100 °C. A microcapsule sample was put on the heating late for in s, and the thermal images were taken each 5 s. Nanoindentation is a robust technique for determination of mechanical properties. By combining the application of low-loads, measuring the resulting displacement, and determining the contact area between the tip of the indenter and the sample a wide range of mechanical properties are able to be measured. The application that drove the innovation of the technique is testing thin film properties for which conventional testing is not feasible. Conventional mechanical testing such as tensile testing or dynamic mechanical analysis (DMA) can only return the average property without any indication of variability across the sample. However, nanoindentation can be utilized for determination of local properties of homogeneous as well as heterogeneous materials. The reduction in sample size requirements has allowed the technique to become broadly applied to products where the manufactured state does not present sufficient material for micro-hardness testing. Applications in this area include medical implants, consumer goods, and packaging. Alternative uses of the technique are used to test devices by utilizing the low-loads and small scale displacements of the nanoindenter . Nanoindentation is a robust technique for determination of mechanical properties. By combining the application of low-loads, measuring the resulting displacement, and determining the contact area between the tip of the indenter and the sample, a wide range of mechanical properties are able to be measured. The application that drove the innovation of the technique is testing thin film properties for which conventional testing is not feasible. Conventional mechanical testing such as tensile testing or dynamic mechanical analysis (DMA) can only return the average property without any indication of variability across the sample. However, nanoindentation can be utilized for determination of local homogeneous properties as well as heterogeneous materials. The reduction in sample size requirements has allowed the technique to become broadly applied to products where the manufactured state does not present sufficient material for micro-hardness testing. Applications in this area include medical implants, consumer goods, and packaging. Alternative uses of the technique are used to test devices by utilizing the low-loads and small scale displacements of the nanoindenter . Nanoindentation technology is now considered as the most convenient and standard method to evaluate the mechanical property of a single microcapsule . The mecThe compactability of microcapsules has been widely studied, especially in the controlled release field of medicine. The release behavior greatly depends on the microstructure of shells. It can be regulated through controlling the shell thickness, core/shell ratio, average size, polymerization dynamics and even pore structure. To simplify the complexity of compactability, the microcapsule samples used in this work are considered with the same average diameter because the emulsion stirring rate determined the average diameter of microcapsule particles . Microca(1)−1 with core/shell weight ratio of 2/1.It was proved that several microcapsule samples had been successfully fabricated by the self-assembly process under various pH values in this work. Emulation states and the surface morphologies of microcapsules were observed. The addition amount of graphene was 5% of shell material in the microcapsule. Microcapsules were fabricated under the emulsion speed of 2000 r·min(2)The addition of graphene did not change the chemical structure of cross-linked HMMM. The existence of graphene had been proved by the EDS results based on the C element in shells. It was found that the microcapsule sample fabricated under pH = 5 owned the largest graphene content in shells. TEM results were used to investigate the state of graphene in a hybrid microstructure.(3)This microcapsule sample fabricated under pH=5 sample had the best thermal stability and larger thermal conductivity because of this sample had more graphene in shells. Moreover, a single microcapsule of this sample had the largest yield point tested by nanoindentation.(4)More graphene decreased the penetrability of core material out of shells. Nanoindentation tests proved this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structures.The additive of graphene in polymeric shell of microcapsules is a promising approach to enhance the physicochemical properties of microcapsules because of its well-known superior characteristics. Graphene can be deposits on shells with the combined action of electrostatic adherence and macromolecular chain-entanglement. The self-assembly amount of graphene is greatly influenced by the acid-base equilibrium. The aim of this work was to investigate the hybrid microstructure and properties of self-assembly graphene/HMMM microcapsules containing paraffin affected by the pH value (3–7) in emulation polymerization. The following conclusions can be drawn:


Graphene, as a typical two-dimensional nanometer material, has shown its unique application potential in electrical characteristics, thermal properties, and thermoelectric properties by virtue of its novel electronic structure. The field of traditional material modification mainly changes or enhances certain properties of materials by mixing a variety of materials (to form a heterostructure) and doping. For graphene as well, this paper specifically discusses the use of traditional modification methods to improve graphene’s electrical and thermoelectrical properties. More deeply, since graphene is an atomic-level thin film material, its shape and edge conformation (zigzag boundary and armchair boundary) have a great impact on performance. Therefore, this paper reviews the graphene modification field in recent years. Through the change in the shape of graphene, the change in the boundary structure configuration, the doping of other atoms, and the formation of a heterostructure, the electrical, thermal, and thermoelectric properties of graphene change, resulting in broader applications in more fields. Through studies of graphene’s electrical, thermal, and thermoelectric properties in recent years, progress has been made not only in experimental testing, but also in theoretical calculation. These aspects of graphene are reviewed in this paper. As the basic unit of C-based materials, graphene can form zero-dimensional fullerenes, curl into one-dimensional C nanotubes, and form graphite by means of AA stacking or AB stacking; see As an ideal two-dimensional 2D) material, graphene has become a popular topic of scientific research due to its distinctive physical and chemical properties since it was first proposed in 2004 ,2,3. MonD materia−1 K−1 [2 V−1 s−1 [Graphene is a transparent conductor that can be used to replace the current liquid crystal display materials . It is o−1 K−1 . At room V−1 s−1 . The lig V−1 s−1 ,13,14, a V−1 s−1 . Graphen V−1 s−1 .2sp orbital hybridization with neighboring C atoms, respectively, in the graphene plane. This regular hexagonal crystal structure makes graphene’s planar structure extremely stable. The tensile elastic modulus of graphene is as high as 1 TPa and the tensile strength is as high as 130 GPa [P orbital contributes to the nonlocalized π and π* bonds, which form the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). The π and π* bonds degenerate at point K in the Brillouin zone (BZ) of graphene; see The ideal graphene is the thinnest two-dimensional crystal (0.35 nm). The bond length between C and C is 0.142 nm , and a singularity occurs at DPs. This means that the effective mass of the electrons in graphene is zero near the Fermi energy level, which also explains the material’s exceptional electrical properties.Graphene’s exclusive crystal and electronic structures give it many novel and inimitable physical properties, including anomalous quantum hall effects (QHEs) ,22,23, aElectron transport properties are similar to those of viscous fluid in strongly related electronics systems, known as the quantum critical effect, which is a typical collision-controlled mass transfer characteristic. However, the study of this phenomenon has been hindered by the lack of macroscopic features of electron viscosity. Levitov et al. determined the vortex characteristics associated with the easy verification of the macroscopic mass transfer performance ,30,31,32It has been a prominent problem that the zero resistance of the viscous flow is related to superconductivity. The viscous flow caused by the vortex leads to the unique macroscopic transport behavior. Levitov et al. predicted that the vorticity of the shear flow with viscosity may cause the return current , which iGraphene’s inimitable electronic properties make it a new infrared frequency domain plasmon waveguide and terahertz metamaterial ,47,48,49Researchers have found that when light hits a single layer of graphene, it can slow down by hundreds of times ,49. ReseThis new approach may eventually become more efficient and adjustable. Highly efficient and controllable plasmon generation properties that are compatible with current microchip technology are a new method of creating core chips for optical circuits, which is a new research direction in the evolution of computer technology toward smaller and more efficient devices.The presence of impurities, especially charged impurities in a lattice, can affect graphene’s electrical properties ,52,53,54Vg at temperature (T) = 9 K. Solid lines of different colors represent different doping concentrations. As shown in the figure, the negative location of the DPs is due to the sample’s n-type doping characteristics, and as the nitrogen doping concentration increases, the DPs moves toward negative values. High-quality nitrogen-doped graphene is prepared using chemical vapor deposition (CVD) methods. The spectral line in The test results confirmed the electron hole valley scattering asymmetry of the charge transport property of the nitrogen-doped graphene. Valley electron scattering is much stronger than hole scattering, and the scattering rate increases with the increase in the nitrogen doping concentration. This is because the nitrogen-doped graphene forms a positive center, causing large-angle scattering for electron transport. Therefore, graphene carrier scattering can be effectively regulated by adding different amounts of graphene nitrogen to control graphene’s electrical characteristics.+ with the supercharged charges on graphene films can detach many electrons from a very precise point [Graphene can also withstand very high currents and quickly balance out missing charges. Researchers conducted an experiment to prove that the electrons in graphene are extremely mobile and react very quickly. Collisions of Xese point . Within Researchers used a single xenon ion to travel through the graphene layer, so that each xenon ion carried approximately 20 electrons through the graphene region. At this point, the C atom with a missing electron is squeezed out of the graphene, and the location of the missing electron is immediately replenished by other electrons, which lasts only a matter of femtoseconds. This means there is a large amount of electron flow in a short period of time; that is, a high density of current is transmitted on graphene. 2, and graphene/Si, among others), VdW heterostructures produced by double layers of graphene are particularly interesting. Because the lattices of the two layers correspond precisely, the physical and chemical properties are equivalent [A van der Waals (VdW) heterostructure is a vertical stack of two-dimensional materials. Based on the rich functionality of two-dimensional materials, more engineering manipulation can be realized to obtain unexpected new characteristics. The graphene-based van der Waals heterostructure is introduced as a substrate from h-BN . The peculiar physical and chemical characteristics of the heterogeneous structure have provoked much interest. Of the many VdW heterostructures based on graphene  have found that the electron properties of vertically stacked graphene heterostructures are closely related to the arrangement of C atoms in graphene . The difFor graphene with a highly ordered structure, the electrical properties depend on symmetry. The MIT researchers created a rotating, twisted, two-layer graphene heterostructure that controls the electron state of the entire system through interactions between the electrons. The dislocation caused by rotation misaligns the electron band structure in the graphene layer and increases the single cell size. Twisted bilayer graphene (TwBLG) produces two new electron states ,64. One The MIT researchers created TwBLG that controls the electron states of the entire system through interactions between electrons. The dislocation caused by rotation misaligns the electron band structure in the graphene layer and increases the single cell size. The study found that in stacked graphene layers, electrical behavior is very sensitive to the arrangement of atoms, affecting the movement of electrons between layers.The surface plasmons of 2D nanomaterials have distinctive electrical properties, and applications such as the interaction between plasmons and electrons and catalytic reactions are also well known, especially in surface plasmons based on grapheme ,68,69,70Cao et al. reported on a plasmon–exciton coupling device . They fi−1 K−1 at a temperature of 350 K. The experimental device configuration is shown in 3 Wm−1 K−1 [In 2008, researchers used confocal micro-Raman spectroscopy to measure the heat transport of suspended graphene nanoribbons ,72. They−1 K−1 [The phonon transmission mode and scattering mechanism of graphene’s thermal conductivity have a significant impact. Numerous studies have shown that the substrate of graphene has an unavoidable effect on its thermal conductivity. After the two-dimensional material contacts the substrate, the thermal conductivity normally decreases significantly after the two-dimensional material contacts the substrate because the thermal conduction is mainly determined by the phonon conduction. When the graphene comes into contact with the substrate ,74,75, t−1 K−1 . Figure It is apparent from the measurement of the thermal conductivity of graphene that all factors, such as the shape and thickness, affect graphene’s thermal conductivity. In general, the size of the graphene in the heat transfer direction is positively correlated with the thermal conductivity. In general, the larger the linear size of graphene, the higher the thermal conductivity; when graphene is on the substrate, the substrate has a great influence on the thermal conductivity. This is because the interaction between the graphene and the substrate leads to changes in the graphene’s lattice constant. The temperature also affects the magnitude of the TC.Based on the relationship between the TC and length, researchers also specifically analyzed the relationship between the TC and the temperature . The resL = 9 μm of graphene. k was proportional to logL at L > 700 nm. This is because the length of graphene is comparable to the phonon mean free path. The researchers also observed that the size far exceeded the ballistic length at 1000 K and at 300 K; see Earlier sections of this article cited examples of theoretical calculations for the TC of graphene . HoweverThe researchers used experimental measurements and nonequilibrium molecular dynamics to simulate the thermal conduction of a single layer of suspended graphene as a function of the temperature and sample length. Different from bulk materials, the thermal conductivity continues to increase at 300 K. Although the length of the sample is much larger than the mean free path of the phonons, the thermal conductivity remains logarithmically discrete with the length of the sample. This is the result of the two-dimensional properties of phonons in graphene, which provides a basis for understanding heat transfer in two-dimensional materials.Many theoretical studies and experiments have shown that the different boundaries and configurations of graphene nanoribbons have a certain impact on the TC ,91,92,93The TC of zigzag-type graphene nanoribbons is 30% higher than that of armchair-type graphene nanoribbons at room temperature, indicating obvious heat transport anisotropy . Figure n > 12, the TC possesses obvious quantization characteristics and is independent of the nanoribbon width. When the nanoribbon width is 2 < n < 12, due to the obvious boundary effect of the nanoribbons, the quantum heat transport is destroyed.Using the nonequilibrium green function (NEGF) method combined with first-principles calculations, researchers revealed the influence of the edge atom position on the TC of graphene nanoribbons . Figure L. Moreover, past studies reported that the bulk three-dimensional phonons in graphene greatly contribute to the TC in the graphene plane. Another theoretical simulation revealed the dependence of the TC on the length of graphene . ResearcMany theoretical calculations and experiments have revealed that graphene’s TC can be changed through the hybridization of grapheme , adsorptZT (the thermoelectric figure of merit) [S is the Seebeck coefficient, T is the average temperature of the device. The formula indicates that the higher the ZT, the higher the conversion efficiency between the device’s thermal energy and electric energy. Outstanding thermoelectric materials must have higher Seebeck coefficients, good electrical conductivity, and very low thermal conductivity. Therefore, it has become a focus of research to identify thermoelectric materials with higher Seebeck coefficient, improve their electronic conductivity, and reduce their thermal conductivity [The performance of thermoelectric materials is generally measured by the thermoelectric optimal value f merit) ,104:(3)Zuctivity ,106,107.ZT at T = 300 K and the ZT at T = 100 K for two different graphene edge heterojunctions. The calculation of the ballistic thermoelectric properties based on graphene nanoribbons heterostructures using the nonequilibrium green function and the Landau transport theory provides a method for understanding the thermoelectric properties of graphene. The phonon heat conduction under the influence of different heterostructures was basically similar, but the influence of the heterostructure geometry and geometric details on electron transport was substantial, and the change in the electronic transport greatly enhanced the thermoelectric properties. These parameters further improve the thermoelectric properties of nanomaterials.Thermoelectric conversion is currently a popular field of research. Researchers studied the ballistic thermoelectric properties of graphene nanoribbon-based heterojunctions . The resThe nonlinear thermoelectric properties of triangular graphene nanoribbons at the armchair boundaries of armchair-GNR (AGNR) and zigzag-GNR (ZGNR) were also modeled by MD . ResearcSpin-dependent thermal effects, or the interaction between spin and thermal current, have been demonstrated in ferromagnetic materials, and the spin Seebeck effect is one of the most interesting phenomena ,111,112.R is the resistance and The spin current caused by the thermal gradient has been detected by the inverse spin Hall effect ,114,115.Researchers prepared graphene-based detection devices and measured their properties and spin thermoelectric parameters. The results show that the thermal gradient of the carriers in a graphene-based transverse spin valve can lead to increased spin voltage in areas near the graphene charge neutrality point (CNP). Similar to the thermal voltage in a thermocouple, the effect caused by the thermoelectric spin voltage can be enhanced by the thermal carrier generated by applying the current ,122,123.S1 and S2. The temperature difference ∆T on both sides of the nanosheets leads to thermoelectric voltage versus (RNL changes slightly with the magnetic induction curve when the carrier concentration is n = −2 × 1011 cm−1 and the electrode current is Idc = 0 (black line) and Idc = 50 μA (red line), respectively. B1 = 30 and B2 = 40. dS/dn (b) about the CNP.The novel electrical and thermal properties of graphene have been gradually recognized, and more applications are being widely used in photoelectric and thermoelectric devices.Polymer composite materials are ideal for horizontal heat dissipation in electronic equipment. Researchers have prepared polymer composites with highly efficient TC ,128,129.−1 K−1 and the anisotropy coefficient is 279; see Ding et al. produced a graphene–nanocellulose composite film using vacuum-assisted self-assembly (VASA). The highly crystalline nanofibers driven by natural forces are conducive to the formation of thermal conduction paths; see Based on graphene’s robust TC and strength, a graphene nanoribbon-based TC modulator was developed in 2011 . By chanAnother interesting study was based on the 3D graphene structure of a curved fold that was transformed by planar graphene . The disWith high TC, graphene absorbs only 2.3% of light, which indicates that it is almost transparent. Based on these two properties, graphene is the best alternative to traditional metal thermometers. Graphene as a thermal microheater can be closely attached to the surface of an optical waveguide without considering the loss of graphene due to light absorption , while g−1, which is nearly double that of traditional devices. The energy consumption of the optical signal reaching 2P phase shift is 3.99 mW, which is lower than that of traditional metal thermal heaters. The optical signal switching speed is 550 ns, which is three orders of magnitude faster than traditional metal thermal microheaters and is far from that of the fastest regulated nanothermal microheater; see Composite photodetectors formed using highly efficient optical materials  and graphene have attracted extensive attention. The photogenerated carriers in the absorbent materials can be effectively transferred to the graphene channel with high mobility to achieve superhigh light response gain ,137,138.2 between graphene and silicon to improve the performance of the photoconductor [2 through the quantum tunneling effect under the condition of illumination. There are no suspension bonds on the surface of the molybdenum disulfide, which reduces the trap state and effectively passivates the interface. Comparing the detection performance of devices before and after MoS2 insertion, the response speed of the latter is three orders of magnitude higher than the former; that is, the response time is 17 ns and the response degree is 3.4 × 104 A/W. Based on graphene/Si hybrid photodetectors, researchers inserted single-layer MoSonductor . The expP-doped graphene-based electrodes improve the performance of the device by reducing its resistance. However, the resistance of the electrode will gradually increase in the environment, which will affect the actual use of the graphene electrode ,145,146.Rsh) decreased by 56% and its surface potential increased by 0.8 V. Moreover, the graphene electrode of this configuration, although treated with a chemical agent, was stable under high temperatures and long-term exposure to air. This graphene-based electrode can be used to produce phosphorescent organic light-emitting diodes with high hole injection and substantial luminescence efficiency.Researchers recently used perfluorinated polymeric sulfonic acid (PFSA) as a dopant molecule to conduct p-doped graphene to build a PFSA-based p-doped graphene electrode . The eleSS) makes it impossible to reduce the working voltage of the integrated circuit to below 0.64 V. Existing transistors that are tunneling FET and negative capacitance FET can realize SS < 60 mV/Dec, but they have a low speed or important defects such as poor stability, unfavorable integration, and thus lack of practical value. The ultralow power consumption transistor to be used in future integrated circuits not only must obtain SS < 60 mV/Dec, ensuring the open state current is sufficiently large, but also requires stable performance and simple preparation [The development trend of integrated circuits has changed from the pursuit of performance and integration to the most effective way to reduce power consumption, which is to reduce the working voltage. Currently, the working voltage of the integrated circuit  of a complementary metal-oxide semiconductor (CMOS) is reduced to 0.7 V, while the thermal excitation limit (60 mV/decade (Dec)) of the MOS transistor’s subthreshold swing , I60 = 40 μA/μm, which is 2000 times the published best tunneling transistor and fully meets the standards of the international semiconductor development roadmap (ITRS) for the practical application of sub-60 mV/Dec devices. The open and closed current of a typical DS transistor at a working voltage of 0.5 V is equivalent to that of a CMOS device at 14 nm (at a working voltage of 0.7 V). This indicates that the DS transistor can meet the requirements of future ultralow power consumption (Vdd < 0.5 V) integrated circuits. Moreover, the device structure of the DS does not rely on semiconductor materials and may be used in conventional CMOS transistors and field effect transistors in two-dimensional materials.Most importantly, the DS-FET has a proposed driving current much higher than that of tunneling transistors compared to metal-oxide semiconductor field-effect transistors, and its Graphene, with its exceptional physical and chemical properties, has been increasingly applied in various fields of scientific research. When graphene’s nanostructure changes , its physical and chemical properties show novel properties. With the improvements in the preparation of graphene nanomaterials and the enhancement of their measurement and regulation, more graphene nanomaterials and their hybrid structures have been applied in electronic, photothermal, thermoelectric, and photoelectric fields.However, graphene’s band gap characteristics limit its application. Graphene’s physical and chemical properties are both closely related to its electronic properties. Graphene’s electronic properties change its physical and chemical properties. There are two kinds of methods. One is a physical approach . The other is a chemical method . The fabrication level of graphene-based microscale or nanoscale devices also determines their application and development. Researchers are actively working in correlated fields, and more high-performance graphene-based devices will be prepared and used in the future.


The stochastic distributed placement of vacancy defects has evident effects on graphene mechanical property, which is a crucial and challenged issue in the field of nanomaterial. Different from the molecular dynamic theory and continuum mechanics theory, the Monte Carlo based finite element method (MC-FEM) was proposed and performed to simulate vibration behavior of vacancy defected graphene. Based on the Monte Carlo simulation, the difficulties in random distributed location of vacancy defects were well overcome. The beam element was chosen to represent the exact atomic lattice of the graphene. The results of MC-FEM have a satisfied agreement with that in the reported references. The natural frequencies in the certain vibration mode were captured to observe the mechanical property of vacancy defected graphene sheets. The discussion about the parameters corresponding with geometry and material property was accomplished by probability theory and mathematical statistics. For the parameters corresponding to material properties of defect-free graphene monolayer, Young’s modulus and intrinsic strength are 1.0 TPa and 130 GPa ,3. VarioGraphene, as a two-dimensional structure, was introduced in 2004 . The maiAttempts and struggles for a deeper understanding of the influence of defects in graphene sheets have been undertaken in this challenging field. For instance, the effect of vacancy defects on Young’s modulus of graphene sheets was discussed by molecular dynamics . The StoThe motivation of this study is to effectively analyze vibration behavior of defected graphene sheets when the vacancy defects are randomly distributed. Since the physical experiments of vacancy defected graphene sheets are difficult and expensive, numerical simulation methods are another promising supplement that need to be developed. Besides, it is necessary to find an effective index to express and observe the effects of vacancy defects in vibration behavior of graphene sheets.In the free vibration, natural frequencies of structures are the essential parameters, which are directly corresponding with the geometrical and material characteristics. The change of the vacancy distribution and location can cause fluctuation in natural frequencies of graphene sheets. The natural frequencies of vibration modes are very sensitive to the geometrical defects. Therefore, natural frequency is a good indicator to discuss the effects of vacancy defects in the graphene sheets.Combining the Monte Carlo simulation with the finite element method to effectively simulate the random dispersed vacancy defects in graphene sheets is a perspective and feasible method. The Monte Carlo simulation as a sophisticated sampling method has been widely applied in the research of phase transition and magnetism of graphene sheets ,21,22,23The remaining part of the paper is organized as follows: a clear introduction about the beam finite element model for representing graphene hexagon microstructure is presented. The Timoshenko beam theory for free vibration analysis is explicitly derived. Besides, the implementation of Monte Carlo based finite element method is expressed in computational program after the validation of deterministic beam finite element model. Good agreement is reached in the present model and reported literatures ,32,33,34Carbon atoms in graphene are bonded together with covalent bonds forming a hexagonal 2D lattice. The parameters to describe the bonds are the bond length and bond angle. The displacement of individual atoms under external forces is constrained by the bonds. In other words, the mechanical deformation of graphene sheets is the result of the interactions between the bonds. Graphene sheets are supposed as planar-frame structures, the bonds act as connecting load-carrying elements, and atoms are assumed as joints of the connecting elements. Then, classical structural mechanics methods such as the finite element method can be applied in the vibration analysis. The elastic geometrical properties of the beam elements have been derived using an energy relationship between molecular mechanics and continuum mechanics developed in . Accordix, y, and z directions and rotations around the x, y, and z axes. BEAM 188 is well-suited for linear, large rotation, and/or large strain nonlinear applications.The numerical simulation model of graphene sheets was created by the ANSYS parameter design language. For the modeling of the C–C bonds, the three-dimensional (3D) elastic BEAM188 element was used . BEAM188The beam elements applied in graphene sheets are based on the Timoshenko beam theory, which is a first order shear deformation theory. In this theory, the transverse shear strain is constant through the cross section, which remains plane and undistorted after deformation.x-axis at point z and time t, and E is the Young’s modulus, G is the shear modulus, The equation derived by Timoshenko that governs flexural vibrations of beams with constant cross section can be expressed as (2)EIρA∂z-axis and a vector orthogonal to the cross section is equal to the angle between the neutral axis tangent line and the z-axis. Note that Besides A, B, C, and In a normal mode, With It is well known that solutions of the above equation behave differently according to Usually, coefficients For free vibration analysis for Timoshenko beam, based on principal of virtual work, the weak form of equation can be written as (8)∫0LEIAs defined above, For free vibrationA general solution can be expressed askth mode.Substituting into Equation (8) yieldsThis is an eigenvalue problem and for non-zero solutions the determinant of the equation must be zeroThe discretization of governing equation can be done by unidirectional linear finite element with two nodes. In each axes direction, there are two degrees of freedom at each node, and six degrees of freedom for each node in total. The approximated solution in the displacement field, transversal displacement and rotation, can be written as (13){ξ=∑Consider the natural coordinate In matrix form, it can be presented byBy substituting to the weak form of equation, the stiffness and mass matrix in element domain are written asFor large symmetric eigenvalue problems, the Block Lanczos eigenvalue extraction method is popular and available . A fast The Monte Carlo approach is a method developed to compute integrals by random number generation. Suppose a complex integral likeDecompose If a large number of random variables from the probability density Consider the integral Therefore, the estimated Monte Carlo standard error can be expressed asBased on Equation (23), when  in 2015 , the numIn order to implement the Monte Carlo based finite element method for vibration analysis of graphene sheets, the flowchart is present in Step 1:Define the initial configuration of graphene sheets, which includes corresponding parameters of bonds’ length, height, and width of a hexagonal 2D lattice, and also thickness or diameter of the section.Step 2:Fix material property parameters, which consist of the Young’s modulus, Poisson ratio, physical density. The accuracy of the finite element model for graphene sheets heavily depends on exact parameters of material property.Step 3:Mesh the beam elements and apply the boundary conditions, which is a traditional step of the finite element method.Step 4:Perform the finite element method and use the Block Lanczos eigenvalue extraction for natural frequencies in each mode vibration of graphene sheets. If the deterministic finite element model is confirmed to be validated, the Monte Carlo simulation will commence, otherwise, return back to the step of initial configuration.Step 5:Apply the Monte Carlo simulation method to randomly disperse vacancy defects in the graphene sheets in the certain percentage. The corresponding number of chosen bonds is evident and can be used to create the vacancy defects in the graphene.Step 6:Mesh the beam elements and apply the boundary conditions, and perform the finite element model computation.Step 7:Capture the natural frequencies of graphene with vacancy defects in the vibration mode and output the results.In order to combine the Monte Carlo simulation with the beam finite element method, the exact design of the computational simulation in the flowchart can be concluded in seven steps:Taking consideration of the effects of stochastic distributed vacancy, the loop needs to repeat to provide reliable and accurate output results. The loop continues until the Monte Carlo simulation is completed.By commercial software of ANSYS , the typical graphene sheet lattice structure is created, which is in accord with the certain sizes in the literatures. In the truss finite element model, there are 6226 trusses, 4212 points and 16,664 nodes created. Performing the beam finite element model for graphene without vacancy defects, a good agreement between the present results and that of relevant references is achieved. From The vacancy defects are quantified according to defect density, which is defined asThe relative error is used to calculate the difference of the mean of the natural frequencies with that of graphene without defects. In the following part, the explicit discussion about the amount of vacancy defects and parameters corresponding to geometrical and material characteristics of graphene sheets are sequentially presented. The results are computed by the Monte Carlo based finite element method and demonstrated by the probability theory and mathematical statistics.Per is 0.5% and 1%, the changes of natural frequencies caused by randomly distributed vacancy defects are not evident. However, the reduction of natural frequencies are abrupt when the percentage of vacancy defects exceeds 1%.The amount of vacancy defects accounted in this study is by the absence of beam in the stochastic placement. The natural frequencies of the beam finite element model as derived in Equation (9) are corresponding to the stiffness and mass matrices. The fluctuation in natural frequencies in different vibration modes is a comprehensive effects of change in Young’s modulus and mass reduction by vacancy defects. According to the relative reference , the elaWhen As mentioned above, natural frequencies are the ratios of stiffness and mass matrices. The appearance of vacancy defects influences both the stiffness and mass matrices. The mass of graphene sheets decreases according to the increase of the amount of vacancy defects. The influence of vacancy defects in Young’s modulus of graphene sheets is not monotonous and non-linear ,41. WhenL, diameter of cross section D, and the amount of hexagons in y axis N, is important and necessary in vibration analysis of graphene sheets.On the basis of molecular mechanics by the energy approach, the tube diameter and length strongly effect the material properties, such as Young’s modulus, shear modulus, bend-angle and strain energy of single- and multi-walled nanotubes . The disL, the mean of first four order natural frequencies is distinctly cut down. The standard variance and error in L is 0.15, with the augmentation of length of each bond in hexagon of graphene sheets, the increase of the first four order natural frequencies compared with that of graphene sheets in L is equal to 0.2, the increases are 82.26%, 82.27%, 82.25%, and 82.22%, respectively. When L is 0.32, the reductions of the first four order natural frequencies of vibration modes are 28.82%, 28.79%, 28.82%, and 28.82%, respectively. Therefore, the length of bond in hexagon of graphene sheets is a crucial factor, which shows a good agreement of size effects in physical experiments and numerical simulation.The results are based on the statistical results by consideration of the random dispersion of vacancy location in the graphene sheets. In L has a negative effect on first four order natural frequencies. The larger L is, the smaller the natural frequencies are. Different from the effects of L in vibration behavior of vacancy defected graphene sheets, with the increase of D, the first four order natural frequencies are amplified. D is 0.02, the reduction of the first four order natural frequencies of vibration modes are 37.51%, 37.49%, 37.49%, and 37.50%, respectively. When D is equal to 0.026, the reduction of the first four order natural frequencies of vibration modes compared with that of graphene in L is 0.04, the increases of the first four order natural frequencies of vibration modes are 24.97%, 25.02%, 24.97%, and 24.99%, respectively. In Equations (2) and (8), both the cross section and inertia moment are related with the diameter of cross section D, which has more complicated effects in natural frequencies of vibration modes. Even though the change of extent in natural frequencies is not as large as the effect of the bond length L, more emphasis should be put on the diameter of cross section D.According to the results above, the geometrical parameter N, the amount of hexagons in y axes, which is not only related to the width of graphene sheets, but also corresponding with the amount of vacancy defects if N is 30, the natural frequencies of the first four orders of vibration mode are 47.90%, 20.83%, 66.55%, and 22.85% larger, respectively. When N is equal to 35, the increase of the natural frequencies of the first four vibration modes compared with that of graphene in N is 45, the reductions of the natural frequencies of the first four order vibration modes are 11.84%, 6.34%, 16.43%, and 11.76%, respectively.There is another geometrical parameter, D, the influence of N in natural frequencies of vacancy defected graphene sheets is more intricate and disproportionate, as in In short, different with the effects of bond length L and the diameter of section cross A large deviation between simulations and experiments in material properties has been found because of the presence of defects in the nanotube structure ,44. The E, namely Young’s modulus, the mean of the first four natural frequencies evidently increased as well. The standard variance and error in E is 800 GPa, the reduction of the natural frequencies of the first four vibration modes compared with that of graphene sheets in E is equal to 1500 GPa, the increase of the natural frequencies of the first four vibration modes compared with that of pristine graphene are 11.79%, 11.82%, 11.80%, and 11.80%, respectively. When E is 2000 GPa, the increments of the natural frequencies of the first four vibration modes are 29.11%, 29.13%, 29.11%, and 29.09%, respectively.From With the augment of Young’s modulus, the values in stiffness matrix of vacancy defected graphene sheets are amplified, while the stiffness matrix is acted as the numerator, which is reasonable to find the enlargement of natural frequencies in vibration modes. Furthermore, as mentioned in the above results, the first four natural frequencies of graphene sheets all have the close magnitude of change. The effects of Young’s modulus in natural frequencies are convergent to the specific percentage in the different vibration modes.V, the results of natural frequencies are very approaching. In other words, the Poisson ratio can be simplified as a neglected factor in the analysis of natural frequencies for vacancy defected graphene sheets.Poisson ratio as one of the parameters corresponding with material properties is discussed in In order to observe the vibration behavior of graphene with vacancy defects, In addition, besides the effects of vacancy defects, impurities in graphene sheets are another unavoidable existence and need more attention . NaturalPer is larger than 1%.The natural frequencies of vibration decrease dramatically with the increase of the vacancy defects when Per reaches 5%.The regular and symmetrical properties of vibration behavior in displacement and rotation are evidently destroyed when Furthermore, with the augment of the vacancy defects quantity, the variances caused by randomly dispersion location of vacancy defects become large.From the discussion about geometrical and material parameters, it can be concluded that the increment of length of each bond in hexagons of graphene sheets distinctly reduces the first four order natural frequencies.For vacancy defected graphene sheets, the amount of hexagons in the long side of the graphene sheet has a similar effect on natural frequencies with length of each bond in hexagon, but it is more complicated.With the increase of thickness of the graphene sheets and Young’s modulus, the natural frequencies of vacancy defected graphene become smaller.In this paper, an effective Monte Carlo based finite element method to analyze the vibration behavior of vacancy defected graphene sheets is proposed. By combining the Monte Carlo method with the beam FE model, the stochastic dispersed placement of vacancies in graphene is successfully propagated and performed. The results show that,