聚氨酯弹性体中NG和BTTN迁移的介观模拟

为在介观尺度下研究聚氨酯弹性体中的硝酸酯增塑剂硝化甘油(NG)和1,2,4-丁三醇三硝酸酯(BTTN)的迁移扩散现象,运用分子模拟软件Materials Studio进行了耗散粒子动力学DPD模拟计算。搭建了粗粒化的介观模型,用此模型计算了NG和BTTN在聚氨酯弹性体中的扩散系数。计算得到NG的介观扩散系数为1.80×10-12m2·s-1,BTTN的扩散系数为0.21×10-12m2·s-1,与文献报道NG的微观扩散系数0.65×10-12~11.10×10-12m2·s-1处于同一数量级上。预聚物分子量提高、温度升高后扩散系数增大,但硝酸酯含量提高后扩散系数降低,同等条件下NG的扩散系数大于BTTN。介观分子模拟计算结果与文献报道值和理论趋势较为符合,说明搭建的硝酸酯/聚氨酯粗粒化模型可以用于考察NG和BTTN在聚氨酯中扩散的情况。     

显微红外光谱法测定EI发射药中钝感剂扩散系数

压伸-浸渍(EI)发射药制造过程中钝感剂的扩散决定了新制火药的内弹道性能。采用红外光谱显微技术考察了聚酯钝感剂PA在EI发射药中的扩散,结果表明新制火药的钝感剂浓度分布符合Fick第二定律的扩散模型,并依据浓度分布曲线方程推算出钝感工艺过程中的钝感剂扩散系数为1.639×10-13m2.s-1。内标法与外标法的比对实验结果表明,在内标法中将钝感层硝化甘油(NG)做均匀分布的数学处理对扩散系数计算结果的数量级没有影响,因此由于数学模型的不完善带来的浓度分布曲线的系统偏差可以忽略不计。     

钝感双基发射药老化迁移机理及动力学过程

为研究钝感双基发射药老化迁移过程及影响因素,利用钝感剂的正态分布特性及Fickian第二扩散定律的推论,建立了钝感发射药老化迁移导致钝感剂浓度分布及燃烧性能变化的理论模型.对6种不同硝化甘油(NG)及邻苯二甲酸二丁酯(DBP)含量的发射药进行不同温度下加速老化实验,采用密闭爆发器测试了不同老化时间后发射药的燃烧性能,分析了发射药老化迁移的动力学过程及热力学影响.理论分析表明,钝感球形发射药燃气生成猛度积分值的增长率随老化时间呈现出较好的线性增长模型.密闭爆发器结果表明,6种发射药加速老化后的动态活度最大值升高百分比随老化时间均呈较强的线性关系,与理论研究结果一致.建立的钝感发射药老化迁移热力学方程与试验结果基本吻合,迁移驱动因子对数与温度的倒数呈现出较为明显的线性负相关.发射药中NG与DBP总含量高于15％时,发射药的迁移驱动因子(动态活度最大值的百分比增长速率)更易受温度影响从而加剧钝感剂迁移导致钝感失效;而NG和DBP的总含量不高于15％时,钝感剂迁移导致失效的速率较为缓慢,更有利于发射药贮存后的使用和射击安全.     

DIANP对NC溶塑作用的实验与模拟

用动态流变实验和扫描电子显微镜观察对比研究了1,5-二叠氮-3-硝基氮杂戊烷(DIANP)和硝化甘油(NG)溶塑硝化纤维素(NC)的速率和效果,用分子动力学模拟方法对DIANP、NG、NC的溶度参数和DIANP、NG在NC中的扩散系数进行了模拟计算,采用介观动力学模拟方法得到了NC/DIANP和NC/NG共混体系的介观形貌。结果表明,与NG相比,DIANP溶塑NC速率较快,二者在NC中的扩散系数分别为1.39×10~(-10)m~2·s~(-1)和2.24×10~(-10)m~2·s~(-1)。相对于NG,DIANP溶塑效果更好,两种共混体系的显微形貌特征与介观动力学模拟结果具有很高的一致性。溶度参数计算结果表明,DIANP的分子间作用力大小与NC较为相似,而NG溶度参数的范德华力和静电力分量所占的比例与NC接近。     

双基球扁药中的钝感剂迁移现象及其对燃烧性能的影响

为研究双基球扁药贮存过程中钝感剂的迁移现象,采用显微拉曼技术,表征了经加速老化后小分子钝感剂邻苯二甲酸二丁酯(DBP)和高分子钝感剂聚新戊二醇己二酸酯(NA)在双基球扁药中的浓度分布状态;并利用密闭爆发器试验,测试了双基球扁药的燃烧性能。结果表明,在由表及里的一维方向上,钝感剂DBP、NA的浓度呈指数规律变化,符合Fick第二扩散定律;加速老化过程中,在双基球扁药中DBP的迁移是双向的,钝感剂分布的浓度梯度会逐渐降低,扩散深度增加,浓度峰值位置向内偏移,双基球扁药燃烧渐增性能也随之下降;高温会加剧钝感剂的迁移现象,65,75,85℃高温条件下老化10天的球扁药样品,其燃烧渐增性特征值分别为1.3351、1.2917、1.1888;随着温度的升高,双基球扁药的燃烧渐增性能下降幅度也随之加大;而在相同条件下,NA较DBP具有更好的抗迁移特性。     

NG在聚氨酯中扩散性能的分子动力学模拟

为研究二异氰酸酯类型、温度、硝化甘油（ NG）含量等因素对NG在聚氨酯弹性体内扩散性能的影响,用分子动力学方法,在COMPASS力场下对NG和聚氨酯弹性体混合体系进行了模拟。构建NG与不同聚氨酯弹性体的混合体系模型,并进行结构优化,先后进行恒温恒压系综（ NPT）和恒温恒容系综（ NVT）的分子动力学模拟,得到NG在混合体系中的均方位移,通过爱因斯坦方程计算得到其扩散系数。结果表明：NG在聚氨酯弹性体内扩散系数的数量级为10-8 cm2· s-1,与实验数据一致;扩散系数随聚氨酯弹性体链的柔顺性增加而上升;随温度的不断升高,扩散系数先缓慢上升,当超过308 K后,扩散系数急剧增加。随NG含量的不断升高,扩散系数先缓慢下降,当超过14％后,扩散系数急剧下降。     

GAP推进剂粘接体系组分迁移动力学研究

为研究组分在缩水甘油叠氮聚醚(GAP)推进剂/端羟基聚丁二烯(HT PB)衬层/三元乙丙(EPDM)绝热层粘接体系中的迁移,采用高效液相色谱(HPLC)测定了经过50,60℃和70℃加速老化后体系中的主要迁移组分,计算了迁移组分的表观扩散活化能和扩散系数。结果表明,老化过程中硝酸酯增塑剂硝化甘油(NG)、1,2,4-丁三醇三硝酸酯(BTTN)发生迁移,两者的表观扩散活化能均在43~121 kJ·mol~(-1),扩散系数在10~(-1)9~10~(-1)6m~2·s~(-1)内。体系中胺类安定剂1(AD1)、胺类安定剂2(AD2)的迁移发生在固化过程,老化过程中主要以消耗为主;GAP推进剂的力学性能与推进剂中AD1的含量有关,AD1含量低于40%时,试件力学性能急剧下降。     

高分子钝感剂在两种发射药中的迁移性能

采用高分子钝感剂NA聚酯湿法钝感得到叠氮硝胺和高能硝胺两种钝感发射药,用高温加速长贮寿命试验的方法来研究NA钝感剂在发射药中的迁移性能。利用密闭爆发器和内弹道试验法,对加速长贮前后的两种钝感发射药动、静态燃烧性能进行研究,结果表明,加速长贮前后两种钝感发射药的爆热、p-t曲线及内弹道性能没有明显变化。利用显微红外光谱法测定两种钝感发射药长贮前后NA钝感剂的浓度分布,结果发现浓度分布也没有变化。表明NA钝感剂抗迁移能力强,可以满足叠氮硝胺发射药和高能硝胺发射药的长贮性能要求,用其制得的钝感发射药具有良好的弹道稳定性能。     

FOX-7/NC/NG在快速热刺激下的自着火行为

在快速压缩机实验平台中利用高速成像及动态压力采集手段研究了FOX-7/NC/NG快速热刺激下的自着火行为.结果表明样品在快速压缩机上止点热力条件为3.0 MPa,598.1 K,环境平均热加载速率约为1.2×104 K·s-1时,未发生自着火;保持压力不变,提高温度至913.1 K,平均热加载速率升高至2.5×104 K·s-1时,样品发生自着火.对样品在3.0 MPa,913 K下的自着火过程进行多次重复实验,发现其着火延迟时间(IDTI)误差小于20％,燃烧持续期误差小于5％;FOX-7/NC/NG样品在不同热加载速率下的实验表明,热加载速率越高,自着火越快,燃烧持续期越短.     

发射药混同过程静电性能测试及风险评估

为评估发射药混同过程中的静电灾害风险,预防事故发生,自主设计了电阻率、介电常数、电荷积累量等静电参数测试装置,并以11/7单基发射药为典型产品进行测试实验,得到其体积电阻率为1.87×10~(10)Ω·m,表面电阻率为1.06×10~(12)Ω,介电常数为1.88,滑槽摩擦状态饱和荷质比为-1.85μC·kg~(-1);采用ANSOFT MAXWELL软件对11/7发射药混同料筒内的静电场进行仿真计算,得到了直径1000 mm混同料筒内11/7发射药最大静电场强随药面高度的变化曲线,结果表明随着药面高度的增加,料筒内电场强度不断增大,当药面高度达到40 mm时,料筒内电场强度已达到空气击穿场强,存在静电放电风险;对不同直径混同料筒的临界放电药面高度进行模拟计算,得到了临界放电药面高度随料筒直径的变化曲线,结果表明直径100,200,300,400,500 mm的料筒,临界放电药面高度分别为81,46,42,41,40 mm,直径超过500 mm时,临界放电药面高度基本维持在40 mm。     

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.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.