不同状态下AZ31镁合金板材V形弯曲性能研究

采用具有不同弯曲半径的V形槽弯曲模具对不同状态、不同厚度的AZ31镁合金板材进行系列弯曲试验,测算AZ31镁合金弯曲回弹量,分析板厚和相对弯曲半径对回弹的影响。研究表明:在凸模弯曲半径r不变时,板带厚度越大,回弹角越小;在板厚一定时,相对弯曲半径r/t越大,回弹角越大;厚度较小板带的回弹角变化幅度受弯曲半径的影响比厚度较大板带的更大;热处理态板材的弯曲成形性能优于冷轧态板材。     

介质覆层对圆柱共形微带天线性能的影响研究

研究了圆柱共形微带天线加载介质层对天线性能的影响。首先采用互易定理分析了加载介质层后圆柱共形微带天线辐射特性,然后运用有限元法计算了天线的方向图．与文献结果进行了比较,验证了程序的有效性。最后。对不同介质覆层厚度和不同覆盖层介电常数下天线的散射参数和辐射方向图进行了仿真。结果表明,圆柱共形微带天线加载介质层后,天线的谐振频率产生了漂移而且阻抗带宽明显降低,介质层厚度对天线阻抗带宽的影响较大,而介电常数的影响相对较小。     

EBG结构在柱面共形微带天线中的应用

利用光学Bragg反射条件,设计了两种曲面电磁带隙结构,观察了其带隙特性,并首次把他们应用到柱面共形微带贴片天线中.仿真结果显示,利用EBG结构后,微带天线的高次谐波得到了很好地抑制.     

近炸引信中的开槽共形定向微带天线

针对近炸引信中贴片微带天线带宽窄及定向辐射性能差等问题,提出了与弹体共形的具有侧向辐射、宽频带的微带天线。该微带天线采用倒方形贴片,在贴片上进行开方形槽,并在槽中加入圆形寄生贴片对天线性能进行优化。仿真与实物测试的结果表明：开槽的共形定向微带天线具有良好的宽带特性,在中心频率7.7 GHz附近方向图具有良好的侧向辐射性能,指标优良且尺寸小,满足近炸引信所需。     

管材弯曲过程中的弹塑性变形分析

在管材弯曲变形的基本假设和简单应力状态下的线性强化材料模型的基础上,对管材弯曲进行了变形分析。分析结果表明：弯管横截面上垂直于弯曲平面方向的对称轴两侧存在很小的弹性区,对弯曲卸载后的回弹产生一定影响;弯曲切向应力主要随相对弯曲半径减小、屈服强度和塑性模量增大而增大;在较小相对弯曲半径范围内,弯曲切向应力有急剧上升的倾向;根据弯曲切向应力小于材料拉伸极限的关系,推导出最小相对弯曲半径的计算公式,理论计算值略小于实际试验值,修正并完善后,可应用于生产。     

共形环状毫米波微带天线研究

与弹体共形天线的复杂结构使天线性能的准确分析十分困难,共形时域有限差分法是分析复杂结构天线的有效方法之一。在介绍共形时域有限差分法基本原理的基础上,分析了毫米波圆锥共形环状微带天线,制作并测试了35GHz的环状微带天线,实测数据与仿真结果吻合。     

弯管横截面畸变的试验与分析

在管材弯曲成形系列研究中,针对弯管壁厚变薄及横截面形状变形现象,展开了试验及有限元模拟分析。在平面应力和三向应力状态假设下,分别推导出弯管壁厚减薄率和横截面短轴变化率相互关系的近似计算公式。通过弯曲试验对公式计算值进行了比较和验证,结果表明,平面应力假设条件下的公式计算值相对准确。相对弯曲半径较大时,弯管外侧管壁材料的径向变形较小,外侧管壁变薄是导致弯管横截面畸变得主要原因。公式计算值与试验结果仍存在一定偏差,通过大量试验进一步修正后,可应用于实际生产。     

刀—屑摩擦对斜角切削切屑流动特性影响的仿真研究

采用显式有限元程序,对不同刀—屑摩擦系数时的斜角切削过程进行三维仿真实验,研究切屑在前刀面上的流动特性,刀—屑摩擦对切屑流动方向和螺旋卷曲半径的影响规律和作用机理。结果表明,斜角切削时,切屑从切削刃处以倾斜方向流出,然后沿前刀面产生侧向弯曲,因此切屑流出速度方向与刀刃法向的夹角逐渐增大;当切屑与前刀面分离后,形成螺旋卷屑排出。刀—屑间摩擦力的分布情况是引起切屑在前刀面上产生侧向弯曲的主要原因。随着刀—屑摩擦系数的增大,切屑在前刀面上侧向弯曲曲率减小,而切屑螺旋卷曲半径增大。而且,刀具前角越小,刀—屑摩擦对切屑流动特性的影响越大。     

可调谐谐振频率的矩形微带天线改进模型

为提高矩形微带天线谐振频率的计算精度，提出了平均有效介电常数的概念，推出了具有和不具有空气隙的矩形微带天线谐振频率的改进公式，并给出了具有空气隙矩形微带天线的谐振频率随空气隙高度的变化曲线，阐述了仿真结果与实验值吻合得较好。     

引信双频环形微带天线的研究

在对环形微带天线进行电阻加载实现天线小型化的基础上。通过对环形天线的C形开槽，实现了天线的双频带工作。采用基于矩量法的电磁仿真软件IE3D进行优化仿真，给出了一个双频环形微带天线的设计仿真结果，此天线适合在无线电引信系统中应用。     

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.