激光测速靶结构优化的光路分析

目的 研究正方形有效靶区位于靶框中央的激光测速靶结构的可行性。方法 分别对采有单圆弧柱面反射镜和双圆弧柱面反射镜方案进行光路分析，确定各主要参数，并通过共轭光学系统的像差分析来验证其合理性。结果 两种模型都能满足方形有效靶区与靶框几何相似且位于靶框中央。结论 经实验论证，单圆弧柱面反射镜方案和双圆弧柱面反射镜方案都是可行的,为设计大口径弹丸用激光测速靶提供了可靠的依据。     

激光光幕靶测速系统设计

针对室内外全天候条件下高精度测量弹丸速度的需求,设计了一种新型激光光幕靶.该激光光幕靶采用线性排列的红外激光管阵列作为发光光源,两列平行排布的红外光敏二极管作为接收器件,形成具有两个光幕的双光幕光幕靶.采用主动式光源,该测速系统测试效率高、精度高且不受天气影响,一次测量系统的CPLD数字逻辑电路可计算得到弹丸的两个飞行时间,便于互相比较和对照.野外实弹试验表明,该测速系统灵敏度高,工作稳定可靠,测试数据准确.     

大面积平行光幕弹着点测试系统

研究了基于平行激光幕大面积弹着点坐标测试方法.以半导体激光线发生器为光源,用长焦距消球差的柱面菲涅耳透镜形成平行激光幕单元,通过多个平行激光幕单元的无缝拼接可形成大面积靶面.由于平行激光幕单元内沿宽度方向通量密度呈高斯分布,一定直径的弹丸通过光幕的不同横向位置时探测器获取信号不同,因此可根据信号的幅值来细分平行激光幕单元宽度范围内弹着点的位置.通过口径为7.62mm的实弹射击试验验证了细分方法的可行性.结果表明了该系统有足够的灵敏度能获取小目标的过靶信号;在10 m长靶面的试验系统中测量坐标值与弹孔测量坐标值差值的标准差为5.16 mm.     

基于大靶面光幕靶的两类六光幕阵列测量原理

弹丸着靶坐标和飞行速度以及飞行方向角是外弹道测试中必测参数,本文针对四幕光幕靶和双光幕测速系统的不足,采用六个大靶面光幕靶,构造出了两类六光幕阵列结构.由作者首次提出的六幕光幕靶是文中所提基本结构的变形.所提六光幕阵列能同时完成着靶坐标、速度和速度方向三类参数的同时测试,是一类六光幕阵列的基本机构,其他结构可以通过光幕面的旋转平移得到.文中给出了两种六光幕阵列测量公式的详细推导.提出的六光幕阵列也可以用作自动报靶系统中的传感器.     

基于光幕靶的亚音速弹和预制破片速度测量算法

针对亚音速弹和预制破片的速度测量,本文基于光幕靶和数据采集卡组成的弹丸测速系统,研究了一种弹形信号识别算法和测量结果处理算法.对亚音速弹,算法依据分拣电平和信号时间宽度大小,能很好地识别出弹形信号和冲击波信号;对预制破片,算法依据过靶信号脉冲宽度与两靶输出信号的时间间隔,识别出预制破片的过靶信号.通过对弹形信号的相关分析处理,即得到弹丸穿过两个光幕的精确飞行时间,进而确定出弹丸速度.经实弹射击验证,算法准确有效,满足靶场测试要求.     

一种光幕测速信号的图像处理技术

在光幕靶精密测速系统中,提出了一种基于图像处理算法的信号处理技术,消除随机噪声对光电探测信号的干扰,从而可以精确荻取物体通过前后两光幕靶的间隔时间.该技术将间隔时间的计算转换为图像中目标物体尾部位置的计算.首先去除孤立点、毛刺等图像缺陷,得到只有一个连通区的图像,再用图像面积除以平均宽度计算物体的长度,求出对应的尾部位置.从前后光幕图像的尾部位置分别得到了物体通过前后两光幕靶的准确时间,两者相减最终得到间隔时间.实验表明系统采用该处理技术能够精确荻取间隔时间,实测的速度数据稳定、有效,测量精度可以达到0.05%.     

基于大靶面光幕靶30mm口径弹丸速度测试技术

针对室内外全天候条件下用光幕靶测试大口径弹丸速度的需求,本文研究了一种新型大靶面光幕靶.采用红外发光二极管阵列作为发光光源,红外光电二极管线阵列组成接收装置,铝合金型材作为结构支撑架,构建的光幕靶探测区域面积最大可以到3m×1m,探测敏感面长度为1m,且该长度可以任意扩展.文中给出了大靶面光幕靶的光幕结构以及电路的详细设计.用12.7mm,14.5mm以及30mm弹丸进行了实弹试验验证,结果表明:设计的光幕靶能抗炮口火光的干扰,对无曳光或曳光较弱的的弹丸能可靠的工作.对曳光较强的弹丸尚无法测试,文中对该问题进行了分析,提出下一步工作思路.     

大靶面光幕靶中发光二极管阵列线光源的设计

采用发光二极管阵列构造线了一种大尺度线光源．文中分析了发光二极管阵列光源能量在空间上的分布,用光照度计实测能量分布数据．以二维坐标给出了能量平面分布图．设计的线光源满足大靶面弹丸测速光幕靶的要求,文中给出了在光幕靶接收器件处阵列线光源光能量的计算公式．实验验证了分析的正确性．     

弹丸着靶坐标测试系统的原理与信号处理电路

分析了4光幕交汇测试弹丸着靶坐标的原理．4个光幕分别由4个大面积光幕靶产生．大面积光幕靶的光源采用发光二极管阵列．接收部分采用PIN红外光电二极管阵列．设计的大面积光幕靶发射部分与接收部分的有效作用距离最大可以达到3m．文中给出了详细的信号处理电路．设计的测试系统用5种轻武器枪弹实弹射击，测试结果与纸靶相比较，其测量误差满足目前枪弹产品检验试验的要求．     

光幕靶测量破片群初速的方法

针对计算战斗部杀伤概率和引战配合参数,提出一种六幕光幕靶对战斗部破片群初速进行测量的方法.给出了六幕光幕靶的测量原理.可以通过测量多个破片的飞行速度与飞行姿态角,推导出速度衰减系数.采用多台六幕光幕靶圆形放置,同时参与测试,再根据破片速度衰减公式确定破片群的初速.同时对沿战斗部轴向的破片初速进行了探讨,用其初速分布更准确地表示战斗部的初速分布,讨论了误差影响因素.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.