A LINEAR SHAPED CHARGE NEUTRON RADIOGRAPHY PRECISE DETECTION SCHEME
Neutron radiography was researched to detect the linear density of explosive in linear shaped charge (LSC), to determine its distribution uniformity and defective. The clear images of some samples were obtained by neutron radiography, and were processed to obtain the linear density of inner explosive. The defectives such as sparseness, discontinuity and cavity were shown clearly in the images. The method, with more intuitive and more reliable results, is more direct and simpler than existing quality testing methods for LSC, and most important, the method is a non-destructive one. This new method is of significance to the precise test of LSC and its application in precise blasting; in addition, it could be used in quality test of cord type explosive device.
Characteristics of Shaped Charges with Hemispherical Liners
During the last 10 years shaped charges with spherical liners have arosed great interest in research and development because their application in special munition results in an increase of performance. The present report presents measured characteristics of shaped charges with hemispherical liners. A short explanation of the jet formation process and the typical jet characteristics as a function of charge geometries are given, and the effect of liner materials is described. Additionally, the influence of various explosives and wave shapers have been studied. The important feature of such shaped charges is that the projectiles are associated with a high terminal ballistic effective part of the liner mass, which is of particular interest for application.
An anionic shell shields a cationic core allowing for uptake and release of polyelectrolytes within core-shell responsive microgels.
To realize carriers for drug delivery, cationic containers are required for anionic guests. Nevertheless, the toxicity of cationic carriers limits their practical use. In this study, we investigate a model system of polyampholyte N-isopropylacrylamide (NIPAM)-based microgels with a cationic core and an anionic shell to study whether the presence of a negative shell allows the cationic core to be shielded while still enabling the uptake and release of the anionic guest polyelectrolytes. These microgels are loaded with polystyrene sulfonate of different molecular weights to investigate the influence of their chain length on the uptake and release process. By means of small-angle neutron scattering, we evaluate the spatial distribution of polystyrene sulfonate within the microgels. The guest molecules are located in different parts of the core-shell microgels depending on their size. By combining these scattering results with UV-vis spectroscopy, electrophoretic mobility and potentiometric titrations we gain complementary results to investigate the uptake and release process of polyelectrolytes in polyampholyte core-shell microgels. Moreover, Brownian molecular dynamic simulations are performed to compare the experimental and theoretical results of this model. Our findings demonstrate that the presence of a shell still enables efficient uptake of guest molecules into the cationic core. These anionic guest molecules can be released through an anionic shell. Furthermore, the presence of a shell enhances the stability of the microgel-polyelectrolyte complexes with respect to the cationic precursor microgel alone.