基于改进Hashin-Shtrikman方法预测PBX有效弹性模量

高聚物黏结炸药(PBX)是一种颗粒高度填充的含能复合材料,其单质炸药晶体的体积百分含量通常达到了80%以上,采用经典的细观力学模型Hashin-Shtrikman界限法获得的PBX有效弹性模量与实验测试值存在较大误差.引入含有炸药密度参数的"界面结合修正系数",得到了一个改进的Hashin-Shtrikman模型.设计了三种密度的以TATB为基的PBX,测定了相应的弹性模量值,并确定了模型的修正系数为0.813(ρ/ρ_0)~(8.64)和0.296(ρ/ρ_0)~(8.68).分别利用经典的和改进的Hashin-Shtrikman模型计算了该型PBX的有效体积模量和有效剪切模量,同时与实验值进行了对比.结果表明:以TATB为基的PBX其有效弹性模量随密度的减小呈指数形式衰减,且体积模量与剪切模量随密度的影响程度几乎一致,其指数约为8.6;改进的Hashin-Shtrikman模型的预测结果与实验值的误差在1%左右;改进后的模型合理,拟合精度高,适合于对双组分PBX有效弹性模量的预测.     

确定隔板圆角ρ的一个近似方法

本文提出了一种确定隔离机构中隔板圆角ρ的近似方法。根据文献[1]的假设和基本思想,计算了ρ处的第一主应力σ_(1 max),直接由应力集中系数曲线得到ρ值,从而克服了确定均布载荷P的困难。     

X80钢三点弯曲裂纹扩展试验及有限元模拟

通过三点弯曲加载方式对X80钢进行裂纹扩展试验,采用GTN模型对裂纹扩展进行有限元模拟分析。结果表明:试样中心部位孔洞充分扩张,边缘部位小孔洞沿滑移带不断形核聚合,裂纹扩展量由试样中心向厚度边缘逐渐降低,形成类似草帽的宏观形貌;孔洞初始体积分数φ_0对GTN模型预测结果影响显著,当试样厚度中心和边缘部位的φ_0分别为0.001 5和0.000 2时,可获得与试验较接近的有限元模拟结果。     

第六节 陀螺设计和外壳

§6-1 敏感元件已设计出的敏感元件,提供了适当地消除输入和输出平面间的耦合,而且还具有适当的速率灵敏度。下面介绍原始的设计计算。梁的基本振动频率从下列公式求出:f_1=(α_1h)/(2πl~2)((EG)/(12ρ))~(1/2)(9)其中α_1=22     

Cu(N_3)_2及其复合结构的分子动力学模拟

采用Material Studio程序构建叠氮化铜Cu(N_3)_2、Cu(N_3)_2/C和Cu(N_3)_2/Si的超晶胞结构,以及Cu(N_3)_2/石墨烯的计算模型,用分子动力学方法对其力学性能进行计算。结果表明:Cu(N_3)_2及其复合结构各自的弹性系数区别较大,均表现出明显的各向异性,且Cu(N_3)_2/石墨烯的弹性系数明显不同于其它3者;复合结构Cu(N_3)_2/C、Cu(N_3)_2/Si和Cu(N_3)_2/石墨烯均具有良好的延展性;体积模量数值表明,加入C和Si使得Cu(N_3)_2断裂强度变化不明显,但石墨烯复合使得Cu(N_3)_2的断裂强度大幅度减小。     

甲苯三段硝化的前线轨道理论

本文运用Hückel分子轨道法(HMO),计算了甲苯及其硝基衍生物系列分子。发现以苯环各位置上的前线电荷密度(ρ_(HOMO,i)可较好地阐明甲苯三段硝化的位置选择性;m-MNT的ρ~(HOMO,i)和硝化异构物百分含量之间存在良好的线性关系。     

无溶剂的能量Ag(Ⅰ)-MOFs的制备及爆炸与安全性能

基于含能配体3,5?二硝基?1?氢?1,2,4?三唑(2?Hntz)和3,4?双(1?氢?5?四唑基)?氧化呋咱(H_2BTOF),水热条件下制备了两例无溶剂的能量Ag(Ⅰ)?MOFs,[Ag_2(2?ntz)_2]_n(1)和[Ag_2(BTOF)]_n(2)。单晶衍射分析表明,Ag~+中心均为三配位,化合物1为由2?ntz~-采取μ_3?1,2,4模式桥联金属形成的三维框架结构(ρ_1=2.805 g·cm~(-3)),化合物2是由BTOF~(2-)通过五齿桥连?螯合模式连接金属形成的二维折叠层状结构(ρ_2=3.101 g·cm~(-3))。综合热分析(TG?DSC)测试表明,化合物1和2均具有较高的热稳定性,在240℃以前保持框架稳定。以氧弹热量计测定了化合物1和2的恒容燃烧热并计算得到标准摩尔生成焓分别为(1375.74±1.27)k J·mol~(-1)和(1647.42±1.46)k J·mol~(-1)。爆轰和安全性能分析表明,化合物1和2的爆热、爆速和爆压值分别为5.55 k J·g~(-1)和3.78 k J·g~(-1),8.97 km·s~(-1)和7.69 km·s~(-1),44.87 GPa和34.37 GPa,对撞击和摩擦不敏感,属潜在的高能钝感材料。     

直接加荷法快速测σ_(0.2)

<正> 一、前言一般说,除退火钢或热轧的低碳和中碳钢等少数合金有屈服现象外,多数经淬火、回火的高强度钢均无明显的屈服点。因此,根据构件在服役中的情况不同,人为规定在标距长度内,产生不同的规定残余伸长的应力作为该种材料的屈服强度,并以σ_(0·01)、σ_(0·05)、σ_(0·1)、σ_(0·2)等表示。     

图线分析法——论证与设计钢珠离心自炸机构的一种方法

本文提出了一种利用中小型电子计算机论证选择离心自炸机构自炸角速度ω_(t0)~*。及设计确定钢珠离心自炸机构基本结构参量的方法。这种方法是首先计算外弹道和弹丸沿弹道的旋转角速度ω,然后输出旋转角速度对于时间的曲线ω-t,通过对不同射角下ω-t曲线族的分析,选择战术要求的ω_(t0)~*。对不同的钢珠数目i,不同的钢珠直径d,可以计算出自炸角速度ω_(t0)与倾角α(参见图2)的关系曲线,输出这个曲线族,根据战术要求选定的ω_(t0)~*。即可分析确定合适的结构参量i,d及α。这种方法便于看清各种不同射角θ_0时自炸炸点分布的情况及自炸炸点位置与最小射角θ_(0min)的关系。从而可以解决这种计算量大、要求考虑全面而因素又不太多的优化设计问题。     

通过本生火焰的硼粉燃烧实验

通过甲烷、氢、氧、氮混合气体本生火焰的硼粉(平均粒径为0.9μm及15μm)燃烧实验,是以混合气单位体积中所含硼粉的重量ρ_s为参数进行。实验结果证明,预混火焰的燃烧速度随着ρ_s的增加而减小,在预混火焰中硼粉起着吸热体的作用。另外,理论计算结果证明,在ρ_s的适当范围内绝热火焰温度增加,同时还求出了实验用气体组成的具体范围。     

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.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

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.