Fabrication of combustion pyrotechnics for laser and electromagnetic interference shielding

The contradiction between flammability and packing density is the technical bottleneck for combustible smoke agent.Herein,polyurethane(PU)foams with flammability and resilience were prepared with polyol and isocyanate as raw materials by chemical foaming method,then compounded with metal powders,polytetrafluoroethylene(PTFE),phthalic annychide(PA),etc.in a certain proportion and pressed into pyrotechnic grain to obtain eco-friendly combustion aerosols with compact density of about1.15 g/cm^(3).The resulting combustion smoke agent combined the advantages of PU foam and pyrotechnic with easy ignition,large smoke production,long duration and low environmental pollution.The transmittance of aerosols for 532 nm and 1064 nm lasers was close to 0,and the EMI SE reached up to65 d B and 35 d B in GPS band and X band,respectively.In addition,the resulting pyrotechnic grains exhibited good mechanical strength and elasticity for sample 1:25,with a compressive strength of22 MPa and an elastic modulus of 195 MPa.The resulting combustion smoke agent is expected to play a potential role in the field of electromagnetic damage and protection.

Characterisation of Lyzls in mice and antibacteria properties of human LYZL6

C-type lysozyme genes （Lyzls） belong to the class of lysozymes and are highly expressed in the testis and epididymis. The members Lyzl4 and Spaca3 have been reported to play a role in sperm-egg binding and fertilisation in mice. However, the function of the remaining two mouse c-type lysozyme genes, Lyzll and Lyzl6, is still not clear. In the present study, we analysed the tissue expression and androgen-dependent expression of mouse c-type lysozyme genes and the possible contribution of human recombinant LYZL6 （rLYZL6） to immunity. The expression of Lyzlswas detected by RT-PCR, Western blots, immunohistochemistry and immunofluorescence. The bacteriolytic activity of rLYZL6 was analysed by a colony-forming assay. In mice, the expression of Lyzlgenes was mainly in the testis and epididymis in a developmentally regulated manner and androgen- or testicular factor-regulated manner. Immunodetection revealed the presence of LYZL6 protein in primary spermatocytes and round spermatids of the testis and on the post-acrosomal area and midpiece of mature epididymal spermatozoa. The rLYZL6 protein exhibited antibacterial activity. From the results, Lyzls may play a role in mitochondrial function of spermatozoa and LYZL6 may contribute to the innate immunity of the male genital tract.

The investigation of NTO/HMX-based plastic-bonded explosives and its safety performance

3-nitro-1,2,4-triazol-5-one(NTO)is the main component of insensitive munitions(IM)formulation because of its outstanding insensitive properties.In this paper,a series of NTO/HMX-based compositeexplosives were prepared and characterized.The study focuses on the effect of NTO on the perfommance of the formulations,especially the safety performance.The results revealed that the mechanical sensi-tivity of fomulations was associated with NTO content,as well as the thermal conductivity,specific heat capacity and Arrhenius parameters.Then,the high amount of NTO using in formulation was proved to be helpful for NTO/HMX-based formulation to exhibit good thermal safety.Besides,by accelerating rate calorimeter(ARC)and a modified cook-off equipment,the pressure and pressure rise rate were proved as the important indicator for judging the thermal safety performance in confined spaces.Finally,the numerical simulation was used as a credible method for predicting the respond temperature of cook-off experiment.

Thermal hazard assessment of TKX-50-based melt-cast explosive

In the present study, thermal hazards of TNT and DNAN used as the molten binder in TKX-50-based meltcast explosives were comparatively studied through accelerating rate calorimeter(ARC) and Cook-off experiments. Two kinds of ARC operation modes were performed to investigate the thermal safety performance under adiabatic conditions(HWS mode) and constant heating(CHR mode). The obtained results demonstrated that at both heating modes, DNAN/TKX-50 outperformed TNT/TKX-50 from the thermal safety point of view. However, the sensitivity to heat of the samples was reverse because of the different heating modes. In addition, the results of thermal hazard assessment obtained from the cookoff experiment complied with ARC analysis which indicated the molten binder TNT replaced by DNAN would reduce the hazard of the TKX-50 melt cast explosive. Furthermore, the results of cook-off experiments also showed that DNAN/TKX-50 outperformed TNT/TKX-50 from the aspect of thermal stability, which was consistent with the result of CHR mode because of the similar heating process.

Shock initiation performance of NTO-based polymer bonded explosive

3-nitro-1,2,4-tri-azol-5-one(NTO) is a high energy insensitive explosive. To study the shock initiation process of NTO-based polymer bonded explosive JEOL-1(32%octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX), 32% NTO, 28% Al and 8% binder system), the cylinder test, the gap experiments and numerical simulation were carried out. Firstly, we got the detonation velocity(7746 m/s) and the parameters of Jones-Wilkins-Lee(JWL) equation of state(EOS) for detonation product by cylinder test and numerical simulation. Secondly, the Hugoniot curve of unreacted explosive for JEOL-1 was obtained calculating the data of pressure and time at different Lagrangian positions. Then the JWL EOS of unreacted explosive was obtained by utilizing the Hugoniot curve as the reference curve. Finally, we got the pressure growth history of JEOL-1 under shock wave stimulation and the parameters of the ignition and growth reaction rate equation were obtained by the pressure-time curves measured by the shockinitiation gap experiment and numerical simulation. The determined trinomial ignition and growth model(IG model) parameters can be applied to subsequently simulation analysis and design of insensitive ammunition with NTO-based polymer bonded explosive.

Research on the Glass Transition Temperature and Mechanical Properties of Poly(vinyl chloride)/Dioctyl Phthalate (PVC/DOP) Blends by Molecular Dynamics Simulations

To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature(Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate(PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference(|Δδ|< 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus(E), bulk modulus(K), and shear modulus(G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.

Expression and function of HSP110 family in mouse testis after vasectomy

HSP110 functions to protect cells, tissues, and organs from noxious conditions. Vasectomy induces apoptosis in the testis; however, little is known about the reason leading to this outcome. The aim of the present study was to evaluate the expression and function of HSP110 in mouse testis after vasectomy. Following bilateral vasectomy, we used fluorescent Terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） to detect apoptosis, Western blotting and immunohistochemistry to examine HSP110 expression and localization. Serum antisperm antibody （AsAb） and testosterone were measured by Enzyme-linked immunosorbent assay （ELISA） and radioimmunoassay, respectively. Expression of endoplasmic reticulum stress （ERS） sensors and downstream signaling components was measured by Reverse Transcription-Polymerase Chain Reaction （RT-PCR）, and the phosphorylation of elF2a and JNK was detected by Western blotting. Vasectomy induced morphologic changes, increased apoptosis in the testis, increased serum AsAb, and decreased testosterone levels. After vasectomy, ORP150 mRNA level was increased first and then decreased, Bcl-2 was decreased, and the expression of HSPA41, GRP78, GADD153, PERK, ATF6, IRE-l, XBP-ls, Bax, Bak, and caspases and the phosphorylation of elF2a and JNK were increased. We present that an ER stress-mediated pathway is activated and involved in apoptosis in the testis after vasectomy. HSPA41 and ORP150 may play important roles in maintaining the normal structure and function of testis.