HTPB/TDI粘结体系的固化反应动力学

为了解决工程应用中遇到的固化终点问题,采用等温与非等温差示扫描量热法(DSC法),通过模拟n级反应动力学模型,并根据Kissinger法、Crane法研究了高聚物粘结炸药(PBX)用端羟基聚丁二烯(HTPB)型粘结体系的固化反应动力学。结果表明,HTPB/TDI粘结体系固化反应的表观活化能为54.61kJ·mol~(-1),反应级数为0.87,指前因子为192.80s~(-1),固化反应热Hu为482.87J·g~(-1)。该体系的固化反应过程中存在自催化现象。加入二月桂酸二丁基锡(T12)催化剂后,粘结体系的固化反应速率增大、反应温度降低。拟合出了固化温度与固化时间之间的函数关系,当固化温度取60℃时,求得固化时间约为3.91天,与实际工程应用中的4~6天相符。     

非等温DSC研究Al/HTPB/TDI体系的固化反应动力学

采用非等温差示扫描量热法(DSC)研究了铝粉对端羟基聚丁二烯/甲苯二异氰酸酯体系(HTPB/TDI)固化反应动力学的影响.结果表明,HTPB/TDI体系的固化反应表观活化能约为51.826 kJ·mol-1,反应级数为0.926,指前因子为2.412×105 min-1; 加入铝粉后,体系的固化峰温降低,表观活化能、反应级数和指前因子分别提高至76.402 kJ·mol-1、0.944、2.53×108 min-1,机理函数仍遵循Avrami-Erofeev方程G(α)=[-ln(1-α)]n,只是方程中的指数n有所变化.铝粉对HTPB/TDI固化反应的影响表现为在反应程度18%前起加速作用,18%后起延缓作用.浅析了铝粉影响HTPB/TDI体系固化的原因.     

HTPB推进剂老化机理的分子模拟

为了研究HTPB推进剂的老化机理,采用量子化学方法,计算了端羟基聚丁二烯-甲苯二异氰酸酯(HTPB-TDI)固化体系中化学键的键能,搜索了HTPB推进剂老化过程中可能发生的四个氧化反应的过渡态。结果表明,与CH2基团相连的C—O键的键能最小,为244.95 kJ·mol-1,在老化降解过程最容易发生断裂。老化过程中可能发生的四种氧化交联反应的活化能均较小,小于HTPB-TDI固化分子降解断裂所需要的能量,说明氧化交联反应是HTPB推进剂老化的主要原因,其中生成三元环氧反应的活化能最小,为12.59 kJ·mol-1。     

PEG/IPDI与PEG/TDI固化反应动力学研究

用二正丁胺滴定法对聚乙二醇(PEG)/甲苯二异氰酸酯(TDI)和PEG/异氟尔酮二异氰酸酯(IPDI)反应体系分别进行了研究,得到了相应体系在不同温度下的反应速率常数和活化能;并探讨了PEG分子量、固化剂的活性、燃烧催化剂和温度等因素对固化反应动力学参数和活化能的影响。结果表明:异氰酸酯和PEG反应为二级反应;PEG/IPDI和PEG/TDI体系固化反应的活化能分别为46.89kJ.mol-1和41.12kJ.mol-1;两体系的反应速率常数随着固化剂的活性和温度的增加而变大。不同活性的固化剂和燃烧催化剂虽影响两体系的固化反应速率常数,但不影响反应级数。     

季戊四醇丙烯醛树脂体系固化动力学及流变特性

采用动态差示扫描量热法(DSC)对季戊四醇丙烯醛树脂体系的非等温固化反应动力学进行了研究。通过Kissinger方程和Crane方程对DSC数据进行了分析,得到固化反应的平均表观活化能为14.32kJ·mol-1,指前因子3.84×103 K,反应级数0.95,建立了该树脂体系的固化动力学模型,发现体系在10,15,20℃·min-1和30℃·min-1升温速率下的固化度分别为0.9503,0.9147,0.8871,0.8695,表明固化反应速率越慢,所得产物的固化度越高。采用粘度实验研究了季戊四醇丙烯醛树脂体系在341,347,353K和359K下固化过程的流变特性,并获得了该树脂体系的粘度模型。     

FT-IR法研究PBT粘合剂的固化反应动力学

为明确3,3-双(叠氮甲基)氧丁环-四氢呋喃共聚醚(PBT)粘合剂与常用固化剂的反应过程,利用傅里叶变换红外(FT-IR)光谱法研究了PBT/多异氰酸酯(N100)、PBT/甲苯二异氰酸酯(TDI)和PBT/TDI/N100体系,50～80℃、TPB催化下的固化反应动力学。结果表明:PBT/N100在整个固化过程中遵循二级反应动力学规律,表观活化能63.10 kJ·mol~(-1),指前因子A=1.63×10~7h~(-1)。含有TDI的体系的固化过程均分为两段,但分段机理不同。PBT/TDI体系整个固化反应遵循二级反应动力学规律,但由于TDI上不同位置—NCO活性的差异,以转化率60%为界线分为两个阶段,转化率小于60%为第一阶段,转化率大于60%为第二阶段,相同温度下,第一阶段的反应速率明显高于第二阶段,两阶段的表观活化能分别为54.71 kJ·mol~(-1)和56.50 kJ·mol~(-1),指前因子分别为4.38×10~7h~(-1)和1.24×10~7h~(-1)。PBT/TDI/N100体系反应由于TDI和N100上—NCO活性的差异也分为两个阶段,转化率小于65%主要发生TDI扩链,表现为二级反应动力学,表观活化能为71.17 kJ·mol~(-1),指前因子A=4.58×10~8h~(-1);转化率大于65%主要发生N100交联,反应速率受扩散控制。TDI/N100复配时,指前因子较单一N100体系和单一TDI前后两阶段分别扩大了28,10,37倍,表明固化剂复配后反应活性位点增加。     

在线红外法研究季戊四醇丙烯醛树脂的预聚反应动力学

采用在线红外法研究了季戊四醇丙烯醛树脂的预聚反应动力学,在反应温度为338.15,348.15 K和358.15 K及催化剂硫酸二乙酯酸(DES)的用量为2%和4%时,监测反应体系中官能团=CH_2浓度的变化,计算得出了该聚合反应的动力学方程,并对固化产物的力学性能进行了研究。结果表明:该反应为二级反应,但该反应初期和后期的表观反应速率、反应活化能相差很大,当DES用量为2%时,反应初期和后期的活化能分别为36.5 kJ·mol~(-1)和49.6.kJ·mol~(-1);当DES用量为4%时,反应初期和后期的活化能分别为61.0 k J·mol~(-1)和69.1 kJ·mol~(-1);DES用量为2%和4%时,DES的用量对固化产物的力学性能影响不明显;反应温度对固化产物的力学性能有显著影响,当DES的用量为2%和4%时,出现在338.15 K时的最大抗拉强度分别为41.99 MPa和41.17 MPa,出现在358.15 K时的最大断裂延伸率分别为8.47%和7.27%。     

不同催化剂条件下HTPB/IPDI黏结剂体系的固化过程

为了解不同催化剂[二月桂酸二丁基锡(DBTDL)、乙酰丙酮铁(Fe AA)、辛酸亚锡(TECH)、三亚乙烯二胺(DABCO)、三苯基铋(TPB)、纳米氧化锌(nano-ZnO)]条件下HTPB/IPDI黏结剂体系的固化过程,采用黏度法研究了45℃时,不同催化剂作用下,端羟基聚丁二烯(HTPB)/异佛尔酮二异氰酸酯(IPDI)体系的黏度-时间关系,并探讨了固化反应速率的变化。结果表明,45℃时,无催化剂和不同催化剂作用下HTPB/IPDI体系的流变反应速率常数分别为:k_(blank)=0.002,k_(DBTDL)=0.045,k_(FeAA)=0.0439,k_(TECH)=0.0335,k_(DABCO)=0.0051,k_(TPB)=0.0036,k_(nano-ZnO)=0.0034。不同催化剂对HTPB/IPDI体系固化反应速率常数的影响效果为:DBTDLFe AATECHDABCOTPBnano-ZnO。在HTPB/IPDI体系中,使用DBTDL,Fe AA,TECH,DABCO,TPB,nano-ZnO作为催化剂时,黏结剂体系的适用期分别为0.3,0.7,1.9,6.7,16,18 h。通过固化过程中浆料适用期和反应速率常数k的变化情况分析,认为TPB更适合作为HTPB/IPDI体系的固化催化剂。黏度对数随时间的增长趋势均呈现出前期快后期慢,向图线右下方偏离的两阶段现象。造成这一现象的主要原因是由于IPDI中NCO基团反应活性的明显差异导致:IPDI中的伯NCO基受到环己烷环和甲基的位阻效应,其反应活性明显低于环上的仲NCO基的反应活性。     

三-(硝基苯基)铋的合成与催化效果

以间硝基氯苯、对硝基氯苯与三氯化铋为原料,通过格氏反应和金属转移方法合成了三-(3-硝基苯基)铋(Ⅰa)和三-(4-硝基苯基)铋(Ⅰb)两种未见文献报道的含能铋络合物,其熔点分别为76~77℃和91~92℃。用差热分析(D TA)法研究了两种络合物对复合固体推进剂丁羟体系固化催化效果。结果表明,两种新型铋络合物对固体推进剂丁羟胶体系都有一定的固化催化效果,添加Ⅰb的丁羟胶体系固化温度为120.2℃,接近于常用的室温固化催化剂三-(乙氧基苯基)铋(TEPB)的放热峰温122.2℃。     

PBT与BPS固化反应特性

为了解叠氮黏合剂/非异氰酸酯固化剂固化体系的反应特性,通过微量热法研究了3,3-双(叠氮甲基)环氧丁烷与四氢呋喃共聚醚(PBT)与非异氰酸酯固化剂-丁二酸二丙炔醇酯(BPS)黏结体系的固化反应过程,采用Kissinger法和Crane法计算了该黏结体系固化反应的动力学参数和特征温度,根据333.15、343.15、353.15和363.15 K四个等温条件下该黏结体系完全固化所需的时间拟合了完全固化时间与温度的方程.结果表明,PBT/BPS黏结体系固化反应的表观活化能为81.94 kJ·mol-1,指前因子为108.48 s-1,反应级数为0.93,固化反应热为-926.88 J·g-1;该黏结体系的凝胶温度为319.29 K,固化温度344.52 K,后固化温度为366.11 K;该黏结体系固化反应中存在自催化现象;拟合出的该黏结体系完全固化时间与温度之间的关系式为y=8.3345×104e-0.02309x-11.116.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

Three-dimensional Numerical Simulation of Combustion Field in the Combustion Chamber

In order to study the effect of rotation on the combustion in the underwater vehicle, a two-phase turbulent combustion process is described with Reynolds stress turbulence model, eddy-dissipation turbulent combustion model, P-1 radiation model and particle tracking model of liquid. The flow in the rotating combustion chamber is simulated at two different working speeds, 0 r/min and 1 000 r/min by Fluent software. The temperature, gas velocity, static pressure of wall and fuel concentration are computed and compared. The results show that the combustion in rotating combustor is faster and more effective.     

Software Communication Architecture Implementation and Its Waveform Application

This paper attempts to do a research on the development of software defined radio（SDR） based on software communication architecture（SCA）. Firstly, SCA is studied and a whole reference model of SCA3.0 core framework （CF） is realized; Secondly, an application-specific FM3TR waveform is implemented on the platform of common software based on the reference model; Thirdly, from the point of view of real-time performance and software reuse, tests and validations are made on the above realized CF reference model and FM3TR waveform. As a result, the SCA-compliant SDR has favorable interoperability and software portability and can satisfy the real-time performance requirements which are not too rigorous.     

Parameter Identification for the Valve Control Cylinder System of a Hydraulic Manipulator

In mechanical, hydraulic and electronic systems, the determination of system parameters is often challenging because liquid parameters often change significantly, due to variations in working and environmental conditions. Therefore, it is of significant practical importance to identify those parameters through experimental procedures. A systematic approach to identifying parameters in the valve controlling cylinder system of hydraulic manipulators is provided. It first derives the transfer function of the system, and then uses P control of PID control to predict system parameters. The predicted parameters are further validated using PID control. The prediction through simulation using MatLab language is utilized, which agrees well with experimental results.     

Dynamic Simulation of the Tank Gun Recoil Response

By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle‘s velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.     

Survey of Controllable Suspension System for Off-road Vehicles

The controllable suspension system can improve the performances of off-road vehicles both on road and cross-country. So far, four controllable suspensions, that is, body height control, active, semi-active and slow-active suspensions, have been developed. For off-road vehicles, the slow-active suspension and the semi-active suspension which have controllable stiffness, damping and body height are more appropriate to use. For many years, some control methodologies for controllable suspension systems have been developed along with the development of modern control theory, and two or more original control methods are integrated as a new control method. Today, for military or civilian off-road vehicles, the R&D of controllable suspension systems is ongoing.     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

An Efficient Key Agreement Framework to MANET

Protocols for key management are compared and evaluated from the point of view on mobile ad hoe networks （MANET）. The issues of fault-tolerance and efficiency of key distribution protocols for group communications in MANET are addressed. Most key distribution protocols existing today are primarily designed for wlre-line networks. These protocols either fail to work as intended or cannot work at all when they are applied to the demanding environment of MANET. Parameters and performance of different protocols are analyzed, and then a fiat is given out, on which new protocols or existing ones are designed and modified, so that they can be robust, scalable and efficient in MANET.     

Finite Element Analysis of Fretting Behavior Between an Engine Cylinder Block and a Main Bearing Cap

The finite element analysis of the fretting behavior between a cylinder block and a main bearing cap is presented. The stresses, relative fretting slip, fretting friction work parameter W and crack initiation location parameter G on the fretting contact surface of the cylinder block are obtained and analyzed. It shows that the fretting fatigue problem of the cylinder block can be quantitatively explained by W or G. The effects of pretightening force, friction factor and material combination of the cylinder block and the main bearing cap are studied. The computational results indicate that the fretting fatigue of the cylinder block can be allayed by increasing the elastic modulus of the cylinder block, but not by changing the other two factors.     

A Physical Model of Electromagnetic Force from PEMA Acted on Metal Projectiles

Electromagnetic armor is a new conceptual combat vehicle technology, which improves remarkably the defensive capability and maneuverability of vehicles. The authors present definitely to apply the electromagnetic theory to analyze the electromagnetic armor. Based on electromagnetics, the experienced expression of projectile and the physical model of PEMA （passive electromagnetic armor） are obtained when electric current flows through the system, and a computer sim- ulation is given.