Estimation of the kinetic parameters for thermal decomposition of HNIW and its adiabatic time-to-explosion by Kooij formula

A differential/integral method to estimate the kinetic parameters （apparent activation energy Ea and pre-exponential factor A） for thermal decomposition reaction of energetic materials based on Kooij formula are applied to study the nonisothermal decomposition reaction kinetics of hexanitrohexaazaisowurtzitane （HNIW） by analyzing nonisothermal DSC curve data. The apparent activation energy （Ea） obtained by the integral isoconversional non-isothermal method based on Kooij formula is used to check the constancy and validity of apparent activation energy by the differential/integral method based on Kooij formula. The most probable mechanism function of thermal decomposition reaction of HNIW is determined by a logical choice method. The equations for calculating the critical temperatures of thermal explosion （T_b） and adiabatic time-to- explosion （t_Tlad） based on Kooij formula are used to calculate the values of Tb and t_Tlad to evaluate the thermal safety and heat-resistant ability of HNIW. All the original data needed for analyzing the kinetic parameters are from nonisothermal DSC curves. The results show that the kinetic model function in differential form and the values of E_a and A of decomposition reaction of HNIW are 3（1 - α）[-ln（1 - α）]2/3, 152.73 kJ mol 1 and 10~11.97 S 1, respectively, and the values of self-accelerating decomposition temperature （T_SADT）, Tb and t_Tlad are 486.55 K, 493.11 K and 52.01 s, respectively.     

Structural Characteristics and Decomposition Mechanism of 2, 2＂-Dimethyl-5, 5＇-Azotetrazole

The geometry and the potential curve of thermal decomposition for 2, 2＇ dimethyl-5, 5＇-azotetraol （2-DMAT） are calculated by ab initio quantum chemistry method. The structural characteristics and decomposition mechanism are carefully studied. It is found that the terrazzo ring satisfies 4n ＋ 2 rule and it is a conjugated π-systems for 2 DMAT, The azotetrazol has aromaic characteristic and its thermal decomposition can proceed in two steps： ring opening and N2 separation, The activation energies of the two steps are 152.3 kJ/mol and 44.67 kJ/mol respectively. The ring opening is the rate-controlling step.     

Numerical Simulation of Airflow Field and Structure Improvement in Engine Compartment of Armored Vehicles with Electric Transmission

When the mechanical drive is changed into the electric transmission,the cooling system of the engine compartment should be altered to meet the new requirement for the increasing in equipment such as electric apparatus.In order to predict and analyze the rationality of cooling system in the virtual engine compartment,the numerical simulation of airflow fields in the engine compartment by using computational fluid dynamics（CFD） technique is necessary.An armored vehicle with electric transmission in the research is taken as the research object.The physical model and mathematical model for the computation of 3D air flow and heat transfer in the engine compartment of an armored vehicle with electric transmission is established.Turbulent flow in the compartment is described by using the standard k-ε two-equation turbulence model.The temperature and velocity fields of 3D air flow in the engine compartment are numerically simulated and analyzed based on different fan＇s flux.A theoretical basis for determination of the fan＇s flux is given by the simulation results.The positions of the air-vent shutter are analyzed.The simulation results show that the different positions of the air-vent shutter can lead to different cooling efficiencies.     

Structural Characteristics and Decomposition Mechanism of 1, l＇-Dimethyl-5, 5＇-Azotetrazole

The geometry and the potential curve of thermal decomposition for 1, l＇dimethyl-5, 5＇-azotetraol （1-DMAT） are calculated by ab initio quantum chemistry method. The structural characteristics and decomposition mechanism are carefully studied, It is found that the terrazzo ring satisfies 4n ＋ 2 rule and it is a conjugated π-system for 1-DMAT. The azotetrazol has aromatic characteristic and its thermal decomposition can proceed in two steps： ring opening and separation N2. The activation energies of the two steps are 243.5 kJ/mol and 64.01 kJ/mol, respectively. The ring opening is the rate-controlling step.     

Calculation Method and Analysis of Blockage Time of Cluster Munitions Against Runway

The blockage probability and the blockage time are two important indexes for assessing the blockage efficiency of cluster munitions against the runway. The improved region-by-region searching method and the random sampling method are proposed to calculate the blockage time by considering the minimum number of craters which need to be re- paired after attack. A minimum leave window （MLW） with the minimum number of craters is found out as a region to be repaired, the blockage probability and the blockage time are calculated by the two methods in which the impact points of the sub-munitions are generated with Monte-Carlo simulation technique. An example is given to show the reasonableness of the two methods under the conditions of adequacy simulating times and enough sampling times, and how to choose the methods in application.     

Study on Random Initiation Phenomenon for Sympathetic Detonation of Explosive

It is important to understand the characteristics of explosive sympathetic detonation for explosive safety. Sympathetic reaction test of GIlL （RDX/A1/Binder） explosive charges with shell are conducted. A model of the sympathetic reaction test is established. The elements-apart method and nodes random-failure method are used in the model to desctibe the expression progress of shell expanding and the randomly forming process of fragments. Random detonation phenomena of acceptor charge are simulated.     

Semi-analytical method for calculating aeroelastic effect of profiled rod flying at high velocity

The key technique of a kinetic energy rod(KER) warhead is to control the flight attitude of rods. The rods are usually designed to different shapes. A new conceptual KER named profiled rod which has large L/D ratio is described in this paper. The elastic dynamic equations of this profiled rod flying at high velocity after detonation are set up on the basis of Euler-Bernoulli beam, and the aeroelastic deformation of profiled rod is calculated by semi-analytical method for calculating the vibration characteristics of variable cross-section beam. In addition, the aeroelastic deformation of the undeformed profiled rod and the aeroelastic deformation of deformed profiled rod which is caused by the detonation of explosive are simulated by computational fluid dynamic and finite element method(CFD/FEM), respectively. A satisfactory agreement of these two methods is obtained by the comparison of two methods. The results show that the semi-analytical method for calculating the vibration characteristics of variable cross-section beam is applied to analyze the aeroelastic deformation of profiled rod flying at high velocity.     

Application of Space-time Conservation Element and Solution Element Method in Intake and Exhaust Flows of High Power Density Diesel Engine

A one-dimensional pipe flow model of single-cylinder diesel engine is established to investigate the intake and exhaust flow characteristics of diesel engine in the condition of high power density （HPD）. A space-time conservation element and solution element （CE/SE） method is used to derive the discrete equations of the partial differential equation for the intake and exhaust systems. The performance parameters of diesel engine with speed of 2100 r/min are simulated. The simulated results are in accordance with the experimental data. The effect of increased power density on charging coefficient is analyzed using a validated model. The results show that the charging coefficient is slowly improved with the increase in intake pressure, and is obviously reduced with the increase in engine speed.     

Reliability Analysis of Piezoelectric Truss Structures Under Joint Action of Electric and Mechanical Loading

Based on the finite dement method（FEM） for the dynamical analysis of piezoelectric truss structures, the expressions of safety margins of strength fracture and damage electric field in the structure element are given considering electromechanical coupling effect under the joint action of dectric and mechanical load. By importing the stochastic FEM, reliability of piezoelectric truss structures is analyzed by solving for partial derivative in the process of solving dynamical response of structure system with mode-superposition method. The influence of dectromechanical coupling effect to rdiability index is then analyzed through an example.     

A Study of New Method for Weapon System Effectiveness Evaluation Based on Bayesian Network

As weapon system effectiveness is affected by many factors,its evaluation is essentially a multi-criterion decision making problem for its complexity.The evaluation model of the effectiveness is established on the basis of metrics architecture of the effectiveness.The Bayesian network,which is used to evaluate the effectiveness,is established based on the metrics architecture and the evaluation models.For getting the weights of the metrics by Bayesian network,subjective initial values of the weights are given,gradient ascent algorithm is adopted,and the reasonable values of the weights are achieved.And then the effectiveness of every weapon system project is gained.The weapon system,whose effectiveness is relative maximum,is the optimization system.The research result shows that this method can solve the problem of AHP method which evaluation results are not compatible to the practice results and overcome the shortcoming of neural network in multilayer and multi-criterion decision.The method offers a new approach for evaluating the effectiveness.     

二安替比林甲烷光度法测定钼合金中钛

研究二安替比林甲烷与钛的显色反应,建立直接测定钼合金中钛的光度分析方法。在1.4 mol/L盐酸介质中,钛与二安替比林甲烷形成1∶3的黄色络合物,最大吸收波长在390 nm处,表观摩尔吸光系数为1.51×104 L(/mol.cm)。在50mL溶液中,钛含量在0.50~50μg符合比尔定律。用于钼合金中钛的测定,相对标准偏差为1.1%~2.2%,标准加入回收率为96%~102%。     

氢对TA16钛合金性能影响研究

研究氢对TA16钛合金显微组织、氢脆行为和应力腐蚀行为的影响,以及TA16钛合金在8.5 MPa高温碱性水中的吸氢性能。结果表明,氢在TA16钛合金中形成面心立方的δ相氢化物TiHx(x=1~2)。在室温条件下,TA16钛合金氢脆敏感性随着合金中的氢含量的增加而增大;在8.5 MPa高温碱性水中,TA16钛合金的应力腐蚀敏感性随着合金中氢含量的增加而增大,但合金中氢的体积浓度小于350 mL/m3时,合金的应力腐蚀敏感指数小于0.2。在8.5 MPa高温碱性水中,TA16钛合金的吸氢量随着浸泡时间的增加而增大,浸泡13 000 h后,TA16钛合金的吸氢体积浓度小于50 mL/m3,合金表面形成的由TiO、TiO2和Ti2O3组成的致密氧化膜。     

十二烷基磺酸钠存在下DBC-偶氮氯膦分光光度法测定化学试剂中的痕量铝

研究在pH 4.3 HAc-NaAc缓冲介质中,Al(Ⅲ)一（DBC-偶氮氯膦）一十二烷基磺酸钠( SDS)体系光度性质。研究结果表明：该显色体系的λmax= 622 nm,ε622nm=1.41×104 L·mol-1.cm-1,络合物组成比为Al(Ⅲ)：(DBC-CPA)=1:1,铝量在0.20～1.20 mg.L-1范围内遵守比耳定律。方法已满意地用于碳酸氢钠、氢氧化钠中痕量铝的测定。     

固相萃取-超高效液相色谱法测定兵器工业生产废水中14种硝基酚类物质残留浓度

为了满足环境水样中痕量硝基酚类污染物检测的要求,在硝基酚快速检测中应用Bond Elut Plexa新型固相萃取柱,建立了快速同时测定兵器工业生产环境水样中三硝基苯酚(苦味酸PA)、三硝基间苯二酚(斯蒂酚酸TNR)和三硝基均苯三酚(TNPG)等14种硝基酚的超高效液相色谱分析方法。水样样品采用固相萃取柱净化,上样5.0 m L,并最终用3.0 m L四氢呋喃洗脱,洗脱液浓缩转溶剂后采用色谱分析。选择全氟苯基色谱柱,以乙腈和乙酸铵及0.1%甲酸作为流动相,梯度洗脱,检测波长为220 nm,在优化的固相萃取前处理和液相色谱分离分析条件下,净化效果满足要求。14种硝基酚类化合物在22 min内实现完全基线分离,在0.1~20 mg/L范围内线性良好,相关系数为0.997 3~0.998 7;检出限为0.02~0.04 mg/L,回收率为82.5%~104.8%,相对标准偏差3.2%~5.7%.本方法已成功应用于生产环境水中实际样品的分析。     

双波长高效液相色谱法分析催泪喷射器内容物

建立了采用双波长，利用简单流动相组成测定催泪喷射器中各有效成分的反相高效液相色谱法。色谱柱为Kromasil C18(250 mm×4.6 mm，5μm)，流动相为甲醇：水(80:20，V/V)，流速0.8 mL／min，柱温25℃；紫外检测波长为227 nm和300 nm.能够清楚地分辨催泪喷射器内容物中主要的3种成分：邻氯苯亚甲基丙二腈(CS)，辣椒素(OC)和二氢辣椒素(DC)．该方法简便快捷，线性关系良好，结果准确可靠，对建立催泪喷射器内容物检测的新质量标准具有参考作用。     

Quantitative Analysis of Components in OC-CS Sprays by High Performance Liquid Chromatography with Double Wavelength UV Detection

The method of reversed-phase high performance liquid chromatography was established for the determination of effective components in OC-CS spray using double wavelength UV detection.The method was utilized under following conditions:a column of Kromasil C18(250 mm × 4.6 mm,5 μm),mobile phase consisting of methanol/water(80 /20) at a flow rate of 0.8 mL/min,column temperature of 25 ℃,and the UV detection at 227 nm and 300 nm.Three key components in OC-CS spray could be distinguished clearly,including o-chlor...     

离子色谱法检测DNTF中痕量阴阳离子残留

利用离子色谱技术建立了新型单质炸药3,4-二硝基呋咱(DNTF)中常见阴阳离子的分析方法,对DNTF精制前后常见阴阳离子进行了定量分析,粗品中阴阳离子含量(μg.g-1)分别为:Na+(53.3),Mg2+(5.5),Ca2+(32.4),HCOO-(2.46),Cl-(1.28),NO2-(12.8),NO3-(28.2)。     

钛及钛合金在美海军舰船上的应用

阐明了钛及钛合金在海洋环境中具有的优点,论述了美海军在新型舰船上开发与应用钛及钛合金研究所取得的进展和成果,分析了美海军钛及钛合金今后发展的主要方向:根据不同使用工况环境要求,研发更多新型海军用钛合金牌号,增加海军用钛合金种类,降低钛材成本,改进焊接材料与工艺.     

Zee-Man石墨炉原子吸收法测定生铁中痕量砷和铅

采用日立公司Z-2000原子吸收光谱仪对生铁中痕量砷和铅进行测定并讨论相关的实验条件,石墨管性能比较、酸的选择、试剂空白的控制、干扰因素及消除、基体改进剂的选择、加热参数的选择、共存离子的影响等。用10g/LNi(NO3)2作基体改进剂,提高砷的灰化温度,检测信号得到扩大,回收率为102%和105%。方法的相对标准偏差为4.73%和4.09%,As的线性范围为0～80μg/L,Pb的线性范围为0～100μg/L。     

超细碳化钛粉体的制备及应用研究进展

碳化钛是一种重要的陶瓷材料,具有高熔点、超硬、化学稳定性、高耐磨性等优良性能,具有广阔的应用前景。综述了超细碳化钛粉体的合成方法及其特点,主要包括碳热还原法、镁热还原法、直接碳化法、热等离子体法、化学气相沉积法、高温自蔓延合成法、反应球磨技术法、微波合成法及其他几种试验方法等,并对碳化钛在复合材料、涂层等材料领域中的应用现状作了简单介绍。