Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries.This s...Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries.This study is based on developing a safer laser driven flyer plate prototype comprised of a laser initiator and a flyer plate subsystem that can be used with secondary explosives.System parameters were optimized to initiate the shock-to-detonation transition(SDT)of a secondary explosive based on the impact created by the flyer plate on the explosive surface.Rupture of the flyer was investigated at the mechanically weakened region located on the interface of these subsystems,where the product gases from the deflagration of the explosive provide the required energy.A bilayer energetic material was used,where the first layer consisted of a pyrotechnic component,zirconium potassium perchlorate(ZPP),for sustaining the ignition by the laser beam and the second layer consisted of an insensitive explosive,cyclotetramethylene-tetranitramine(HMX),for deflagration.A plexiglass interface was used to enfold the energetic material.The focal length of the laser beam from the diode was optimized to provide a homogeneous beam profile with maximum power at the surface of the ZPP.Closed bomb experiments were conducted in an internal volume of 10 cm^(3) for evaluation of performance.Dependency of the laser driven flyer plate system output on confinement,explosive density,and laser beam power were analyzed.Measurements using a high-speed camera resulted in a flyer velocity of 670±20 m/s that renders the prototype suitable as a laser detonator in applications,where controlled employment of explosives is critical.展开更多
Bladder carcinoma is the most common tumor in the urinary system. In 1996, a sampleinvestigation showed that bladder carcinoma, in which more than 90% was mainly primary bladder transitional cell carcinoma (BTCC), w...Bladder carcinoma is the most common tumor in the urinary system. In 1996, a sampleinvestigation showed that bladder carcinoma, in which more than 90% was mainly primary bladder transitional cell carcinoma (BTCC), was one of the ten highest mortality malignant tumors in China. Bladder carcinoma represented 2% of all malignant tumors and has the fifth most common malignancy in men in Europe and North America.展开更多
Melting simulation methods are of crucial importance to determining melting temperature of materials efficiently.A high-efficiency melting simulation method saves much simulation time and computational resources.To co...Melting simulation methods are of crucial importance to determining melting temperature of materials efficiently.A high-efficiency melting simulation method saves much simulation time and computational resources.To compare the efficiency of our newly developed shock melting(SM)method with that of the well-established two-phase(TP)method,we calculate the high-pressure melting curve of Au using the two methods based on the optimally selected interatomic potentials.Although we only use 640 atoms to determine the melting temperature of Au in the SM method,the resulting melting curve accords very well with the results from the TP method using much more atoms.Thus,this shows that a much smaller system size in SM method can still achieve a fully converged melting curve compared with the TP method,implying the robustness and efficiency of the SM method.展开更多
Large olivine samples were hot-pressed synthesized for shock wave experiments. The shock wave experiments were carried out at pressure range between 11 and 42 GPa. Shock data on olivine sample yielded a linear relatio...Large olivine samples were hot-pressed synthesized for shock wave experiments. The shock wave experiments were carried out at pressure range between 11 and 42 GPa. Shock data on olivine sample yielded a linear relationship between shock wave velocity D and particle velocity u described by D=3.56(?0.13)+2.57(?0.12)u. The shock temperature is determined by an energy relationship which is approximately 790°C at pressure 28 GPa. Due to low temperature and short experimental duration, we suggest that no phase change occurred in our sample below 30 GPa and olivine persisted well beyond its equilibrium boundary in metastable phase. The densities of metastable olivine are in agreement with the results of static compression. At the depth shallower than 410 km, the densities of metastable olivine are higher than those of the PREM model, facilitating cold slab to sink into the mantle transition zone. However, in entire mantle transition zone, the shock densities are lower than those of the PREM model, hampering cold slab to flow across the "660 km" phase boundary.展开更多
文摘Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries.This study is based on developing a safer laser driven flyer plate prototype comprised of a laser initiator and a flyer plate subsystem that can be used with secondary explosives.System parameters were optimized to initiate the shock-to-detonation transition(SDT)of a secondary explosive based on the impact created by the flyer plate on the explosive surface.Rupture of the flyer was investigated at the mechanically weakened region located on the interface of these subsystems,where the product gases from the deflagration of the explosive provide the required energy.A bilayer energetic material was used,where the first layer consisted of a pyrotechnic component,zirconium potassium perchlorate(ZPP),for sustaining the ignition by the laser beam and the second layer consisted of an insensitive explosive,cyclotetramethylene-tetranitramine(HMX),for deflagration.A plexiglass interface was used to enfold the energetic material.The focal length of the laser beam from the diode was optimized to provide a homogeneous beam profile with maximum power at the surface of the ZPP.Closed bomb experiments were conducted in an internal volume of 10 cm^(3) for evaluation of performance.Dependency of the laser driven flyer plate system output on confinement,explosive density,and laser beam power were analyzed.Measurements using a high-speed camera resulted in a flyer velocity of 670±20 m/s that renders the prototype suitable as a laser detonator in applications,where controlled employment of explosives is critical.
基金This work was supported by a grant from the National Nature ScienceFoundation of China (No.3000754)
文摘Bladder carcinoma is the most common tumor in the urinary system. In 1996, a sampleinvestigation showed that bladder carcinoma, in which more than 90% was mainly primary bladder transitional cell carcinoma (BTCC), was one of the ten highest mortality malignant tumors in China. Bladder carcinoma represented 2% of all malignant tumors and has the fifth most common malignancy in men in Europe and North America.
基金Supported by the National Natural Science Foundation of China under Grant No.41574076the NSAF of China under Grant No.U1230201/A06the Young Core Teacher Scheme of Henan Province under Grant No.2014GGJS-108
文摘Melting simulation methods are of crucial importance to determining melting temperature of materials efficiently.A high-efficiency melting simulation method saves much simulation time and computational resources.To compare the efficiency of our newly developed shock melting(SM)method with that of the well-established two-phase(TP)method,we calculate the high-pressure melting curve of Au using the two methods based on the optimally selected interatomic potentials.Although we only use 640 atoms to determine the melting temperature of Au in the SM method,the resulting melting curve accords very well with the results from the TP method using much more atoms.Thus,this shows that a much smaller system size in SM method can still achieve a fully converged melting curve compared with the TP method,implying the robustness and efficiency of the SM method.
基金the National Natural Science Foundation of China (Grant Nos. 41174074 & 41174073)the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX2-EW-118)
文摘Large olivine samples were hot-pressed synthesized for shock wave experiments. The shock wave experiments were carried out at pressure range between 11 and 42 GPa. Shock data on olivine sample yielded a linear relationship between shock wave velocity D and particle velocity u described by D=3.56(?0.13)+2.57(?0.12)u. The shock temperature is determined by an energy relationship which is approximately 790°C at pressure 28 GPa. Due to low temperature and short experimental duration, we suggest that no phase change occurred in our sample below 30 GPa and olivine persisted well beyond its equilibrium boundary in metastable phase. The densities of metastable olivine are in agreement with the results of static compression. At the depth shallower than 410 km, the densities of metastable olivine are higher than those of the PREM model, facilitating cold slab to sink into the mantle transition zone. However, in entire mantle transition zone, the shock densities are lower than those of the PREM model, hampering cold slab to flow across the "660 km" phase boundary.