Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to en...Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.展开更多
The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization pr...The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization process, the effect of additives glucose, sucrose and poly ethylene glycol-2000 and wetting solvent of isopropyl alcohol were studied. Taguchi experimental design was used for optimization of the operating conditions. The type of additive, the amount of additive(%wt.), solvent of wetting and wetting time were selected for optimization of the conditions. By using 4 factor and 3 levels, 27 experiments were conducted(L27). Results showed that in the presence of 2 %wt. of sucrose additive and isopropyl alcohol solvent, the agglomerations of particles were decreased so that a decrease 30-50% in the average of particles size was seen. Addition additives were effective in storage container and for reduce the agglomeration of particles during storage. Also, the agglomeration rate of particles was reduced over time at optimized conditions. Imaging optical microscopy, scanning electron microscopy(SEM), and particle size analyzer(PSA) methods were used for particles size analyzing as a response in statistical optimization and quality control of the final product. The sensitivity to some mechanical and shock stimuli on the RDX in presence of sucrose additive was tested and the obtained results showed the insignificant effect of additive on the safety properties of pure RDX.展开更多
Constructing tandem solar cells(TSCs)is a strategy to enhance the power conversion efficiency(PCE)of single-junction photovoltaic technologies.Herein,efficient four-terminal(4 T)perovskite-organic TSCs are developed v...Constructing tandem solar cells(TSCs)is a strategy to enhance the power conversion efficiency(PCE)of single-junction photovoltaic technologies.Herein,efficient four-terminal(4 T)perovskite-organic TSCs are developed via precise control over the crystallization with co-anti-solvents in wide-bandgap perovskite(FA_(0.8) Cs_(0.2) Pb(I_(0.6) Br_(0.4))_(3),energy gap:1.77 eV)film.High-quality perovskite films can be achieved by employing a sophisticated co-anti-solvent technique,which effectively enhances the perovskite crystallinity with large grain size and suppresses the nonradiative recombination with pinhole-free surfaces.The results demonstrate that co-anti-solvents with a low boiling point polarity and nonpolar solvent contribute to superior performance of devices.The wide bandgap semi-transparent perovskite solar cell(ST-PSC)fabricated using co-anti-solvent exhibited a remarkable efficiency of 14.52%,and we successfully obtained an efficiency of 22.5%for 4 T perovskite-organic TSC.These findings inspire bright futures that TSCs could facilitate the development of more effective and sustainable solar energy solutions.展开更多
In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward an...In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward and discussed for the preparation of explosive micro-particles. The satisfactory micro-particles of explosives can be obtained easily by its particular mechanism of creating micro-particles, and operating conditions at normal temperature. This method is good for further study and development.展开更多
文摘Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.
基金the research committee of Malek-ashtar University of Technology (MUT) for supporting this work
文摘The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization process, the effect of additives glucose, sucrose and poly ethylene glycol-2000 and wetting solvent of isopropyl alcohol were studied. Taguchi experimental design was used for optimization of the operating conditions. The type of additive, the amount of additive(%wt.), solvent of wetting and wetting time were selected for optimization of the conditions. By using 4 factor and 3 levels, 27 experiments were conducted(L27). Results showed that in the presence of 2 %wt. of sucrose additive and isopropyl alcohol solvent, the agglomerations of particles were decreased so that a decrease 30-50% in the average of particles size was seen. Addition additives were effective in storage container and for reduce the agglomeration of particles during storage. Also, the agglomeration rate of particles was reduced over time at optimized conditions. Imaging optical microscopy, scanning electron microscopy(SEM), and particle size analyzer(PSA) methods were used for particles size analyzing as a response in statistical optimization and quality control of the final product. The sensitivity to some mechanical and shock stimuli on the RDX in presence of sucrose additive was tested and the obtained results showed the insignificant effect of additive on the safety properties of pure RDX.
基金Projects(U23A20138,52173192,52203250)supported by the National Natural Science Foundation of ChinaProject(2022YFB3803300)supported by the National Key Research and Development Program of ChinaProject supported by the State Key Laboratory of Powder Metallurgy,Central South University,China。
文摘Constructing tandem solar cells(TSCs)is a strategy to enhance the power conversion efficiency(PCE)of single-junction photovoltaic technologies.Herein,efficient four-terminal(4 T)perovskite-organic TSCs are developed via precise control over the crystallization with co-anti-solvents in wide-bandgap perovskite(FA_(0.8) Cs_(0.2) Pb(I_(0.6) Br_(0.4))_(3),energy gap:1.77 eV)film.High-quality perovskite films can be achieved by employing a sophisticated co-anti-solvent technique,which effectively enhances the perovskite crystallinity with large grain size and suppresses the nonradiative recombination with pinhole-free surfaces.The results demonstrate that co-anti-solvents with a low boiling point polarity and nonpolar solvent contribute to superior performance of devices.The wide bandgap semi-transparent perovskite solar cell(ST-PSC)fabricated using co-anti-solvent exhibited a remarkable efficiency of 14.52%,and we successfully obtained an efficiency of 22.5%for 4 T perovskite-organic TSC.These findings inspire bright futures that TSCs could facilitate the development of more effective and sustainable solar energy solutions.
基金Sponsored by the National Science Research Foundation of China(20176003)
文摘In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward and discussed for the preparation of explosive micro-particles. The satisfactory micro-particles of explosives can be obtained easily by its particular mechanism of creating micro-particles, and operating conditions at normal temperature. This method is good for further study and development.
