一组新型希伯尔(SCHIEBEL)探测器

被美军称做ＡＮ／ＰＰＳ－１２实为ＡＮ－１９／２希伯尔探雷器,曾在海湾战争后科威特的扫雷行动中发挥了重要作用,一时名声鹊起。这里介绍的是此种牌号从袖珍至大型探雷器系列。     

离散Hartley变换的一种快速递归算法

一些实际应用表明,对实序列数据处理Ｈａｒｔｌｅｙ变换比富反变换更有效更经济。本文首先从代数角度出发,给出离散Ｈａｒｔｌｅｙ变换（ＤＨＴ）系列阵的一种块分解式,籍此导出计算Ｎ＝２＾ｔ点实序列ＤＨＴ的一种快速递归算法,其算术复杂性为Ｍ＝１／２Ｎｌｏｇ２Ｎ＋Ｏ（Ｎ）个实乘和Ａ＝１１／２Ｎｌｏｇ２Ｎ＋Ｏ（Ｎ）个实加。显然该递归算法属目前复杂性最低的一类算法。     

烧结助剂对热压SiCw/Si3N4复合材料性能的影响

本文通过热压的方法分别制得以Ｙ２Ｏ３－Ａｌ２Ｏ３和Ｙ２Ｏ３－Ｌａ２Ｏ３为烧结助剂的ＳｉＣｗ／Ｓｉ３Ｎ４陶瓷基复合材料，对比了采用不同种类及含量的烧结助剂的ＳｉＣｗ／Ｓｉ３Ｎ４复合材料的性能结果，发现烧结助剂的种类及含量对ＳｉＣｗ／Ｓｉ３Ｎ４复合材料的弯曲强度和断裂韧性有明显的影响，对高温弯曲强度的影响尤为显著。     

贯彻群众公认原则

贯彻群众公认原则ＧＵＡＮＣＨＥＱＵＮＺＨＯＮＧＧＯＮＧＲＥＮＹＵＡＮＺＥ●马立新魏云胜干部工作中坚持群众公认原则,这已不是什么新生事物,它本来就是我们党的群众路线的重要组成部分。可是为什么现在一再提倡、一再要求,原因就是在贯彻落实上还有不尽人意之处,...     

二维余散余弦变换的快速递归分解算法

本文讨论了二维离散余弦变换（ＤＣＴ）的快速计算。借助于下标分解,我们将一个Ｎ１×Ｎ２点二维ＤＣＴ分解为四个Ｎ１／２×Ｎ２／２点二维ＤＣＴ,从而导出了二维ＤＣＴ的一种快速递归分解算法。对Ｎ１×Ｎ２点二维实ＤＣＴ的计算,其算术复杂性为Ｏ（Ｎ１Ｎ２ｌｏｇ２Ｎ１Ｎ２）。与文［６］提供的混合算法类同,乘法量比行列算法减少约２５％。     

(G2-continuous) SHAPE PRESERVING CUBIC INTERPOLATION SPLINE CURVE

（Ｇ~２－ｃｏｎｔｉｎｕｏｕｓ）ＳＨＡＰＥＰＲＥＳＥＲＶＩＮＧＣＵＢＩＣＩＮＴＥＲＰＯＬＡＴＩＯＮＳＰＬＩＮＥ　ＣＵＲＶＥＦａｎｇＫｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＳｙｓｔｅｍＥｎｇｉｎｅｅｒｉｎｇａｎｄＭａｔｈｅｍａｔｉｃｓ,ＮＵＤＴ,Ｃｈａｎｇｓｈ?..     

用溶胶-凝胶法制备碳纤维三维编织物增强氧化铝基复合材料的研究

本文研究了溶胶－凝胶（Ｓｏｌ－ｇｅｌ）法制备碳纤维三维编织物增强氧化铝（Ａｌ２Ｏ３）基复合材料的成型工艺及其力学性能，研究了两种主要起始物Ａｌ（ＮＯ３）３、ＡｌＣｌ３配制的氧化铝溶胶对复合材料成型工艺和力学性能的影响。分别以Ａｌ（ＮＯ３）３和ＡｌＣｌ３为起始物，制备得到Ⅰ＃、Ｉ＃复合材料。研究表明，以Ａｌ（ＮＯ３）３为起始物配制的溶胶粘度较小，利于材料的致密化。经过溶胶浸渍、凝胶、裂解１３个周期后，Ⅰ＃材料的密度和室温三点弯曲强度分别为１．８６ｇ／ｃｍ３和１４５．２ＭＰａ，而ＩＩ＃材料的密度和室温三点弯曲强度分别为１．６３ｇ／ｃｍ３和１０４．１ＭＰａ，材料均呈典型的韧性断裂模式。用扫描电子显微镜（ＳＥＭ）观察试样的断口形貌，发现断口表面有大量的纤维拔出，纤维表现了较好的增韧效果。     

AN UNIFIED METHOD AND THEORY FOR GRAMMAR DESIGN OF A CLASS OF CONTEXT-SENSITIVE LANGUAGES

ＡＮＵＮＩＦＩＥＤＭＥＴＨＯＤＡＮＤＴＨＥＯＲＹＦＯＲＧＲＡＭＭＡＲＤＥＳＩＧＮ　ＯＦＡＣＬＡＳＳＯＦＣＯＮＴＥＸＴ－ＳＥＮＳＩＴＩＶＥＬＡＮＧＵＡＧＥＳＬｉＺｈｏｕｊｕｎ;ＣｈｅｎＨｕｏｗａｎｇ;ＬｉＫａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｏｍｐｕｔｅｒ...     

指导先进连队全面建设

指导先进连队全面建设ＺＨＩＤＡＯＸＩＡＮＪＩＮＬＩＡＮＤＵＩＱＵＡＮＭＩＡＮＪＩＡＮＳＨＥ●王洪徵“双争”评比中,老先进连队“落马”的现象比较突出。这一方面说明,“双争”活动在基层开展得比较活跃;另一方面也表明,先进连队建设滑坡问题需要引起足够重视。...     

A BENDING DAMAGE THEORY FOR BEAMS UNDER PURE BENDING LOADS

ＡＢＥＮＤＩＮＧＤＡＭＡＧＥＴＨＥＯＲＹＦＯＲＢＥＡＭＳＵＮＤＥＲＰＵＲＥＢＥＮＤＩＮＧＬＯＡＤＳＹａｎｇＧｕａｎｇｓｏｎｇ;ＬｕＹｉｎｃｈｕ;ＪｉｎＸｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＡｅｒｏｓｐａｃｅＴｅｃｈｎｏｌｏｇｙ,ＮＵＤＴ,Ｃｈａｎｇｓｈａ,...     

基于禁忌搜索算法的指挥控制系统网络组织优化方法

基于复杂网络的拓扑结构优化理论与禁忌搜索算法,结合指挥控制系统的特点,建立了优化最优指挥与控制系统网络结构（Command and Control Architecture Network,C2AN）模型,并以复杂网络的网络效率和网络成本分别描述C2AN中的信息传播效率及构建C2AN的资源消耗,建立优化的目标函数,通过禁忌搜索算法获得了最优的C2AN。最后通过仿真实例,分析了最优C2AN生成过程及其基本统计特征。     

偶联剂在固体推进剂填料改性中的应用研究

本文采用硅烷类和钛酸酯类偶联剂对固体推进剂中的硝酸铵填料进行表面改性。改性后的硝酸铵接触角增大,表面张力降低且具有明显的疏水性。并证实偶联剂可以增强填料与粘结体系之间的界面相互作用。     

基于USB的2FSK调制解调器设计

基于USB的2FSK调制解调器采用USB设备开发方案,以AN2131QC为核心设计硬件,调制单元通过按位分析数据并控制82C53输出不同频率的方波实现;解调单元通过LM2917对2FSK信号进行频压转换并比较滤波实现.该调制解调器既具有便携性、实时性和准确性,也可广泛应用于低频段2FSK信号的调制解调.     

基于散射探测的鱼眼激光告警方法

分析了鱼眼激光告警系统的工作原理,建立了基于散射探测的鱼眼激光告警系统的探测模型,推导出系统的目标光斑成像公式及目标光斑到达探测系统的单像元能量公式,最后引用美国休斯飞机公司AN/TVQ-2激光目标指示器参数进行数值模拟分析,得出激光传输距离及鱼眼告警系统设置高度与探测器单像元能量的关系。     

Surface modification of ammonium nitrate by coating with surfactant materials to reduce hygroscopicity

Ammonium nitrate (AN) is promising oxidizer in green propellants. In this work, the physical coating method was improved to modify the surface of ammonium nitrate particles with different surfactant materials to reduce hygroscopicity. Cetylalcohol, stearic acid, stearyl alcohol, palmic acid, lauric acid, stearsmide, tetradecylamine, dodecylamine, and tetradecanol were used as coating surfactant agents. The hygroscopicity was tested for ammonium nitrate with and without coating. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the surface of coated and uncoated ammonium nitrate. The mass ratio of coating layer and decline of absorption rate of ammonium nitrate coated by cetylalcohol were 1.00%, and 28.40%, respectively. The results indicate that coating with cetylalcohol surfactant have advantages over the other surfactants in term of low mass ratio of coating layer, and high decline of moisture absorption rate. Thus, cetylalcohol would be a promising coating surfactant material for ammonium nitrate. The idea and approach presented in this study have potential to made hydrophobic layer on the surface of particles to reduce hygroscopicity of AN, and also help the researcher to improving anti-hygroscopicity of ammonium salts.     

虚拟战场电磁环境雷达信号建模方法

针对典型地空反辐射导弹武器仿真系统中虚拟战场电磁环境仿真分系统的实际需求,以典型机载雷达AN/APS-145为例,在对其信号载频、脉宽、重频、脉冲幅度等主要性能参数进行系统分析的基础上,研究了应用于虚拟战场电磁环境仿真系统的雷达信号建模方法,仿真实验验证了该方法的正确性与可实现性。     

Preparation of ammonium nitrate-based solid composite propellants supplemented with polyurethane/nitrocellulose blends binder and their thermal decomposition behavior

To improve the performance of solid composite propellants (SCPs) supplemented with ammonium nitrate (AN) as an oxidizer, the incorporation of energetic ingredients such as explosives, energetic binders or catalysts is a common effective approach. For this purpose, polyurethane (PU), a typical inert binder, was mixed with nitrocellulose (NC) as an energetic polymer. Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared. The prepared formulations were characterized using Fourier transform infrared spectroscopy (FTIR), RAMAN spectroscopy, X-ray diffraction (XRD), electron densimetry, thermogravimetric (TG) analysis, and differential scanning calorimetry (DSC). A kinetic study was then performed using the iterative Kissinger-Akahira-Sunose (It-KAS), Flynn-Wall-Ozawa (It-FWO), and non-linear Vyazovkin integral with compensation effect (VYA/CE) methods. The theoretical performances, such as theoretical specific impulse, adiabatic flame temperature, and ideal exhaust gaseous species, were also determined using the NASA Lewis Code, Chemical Equilibrium with Application (CEA). Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants. According to density tests, the density of the propellant increases as the nitrocellulose component increases. According to the thermal analysis and kinetics study, the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants. Based on the theoretical study, increasing the amount of NC in the propellant increased the specific impulse and, as a result, the overall performance.     

Meeting seasonal demand for products with limited shelf lives

This article addresses a common misconception concerning production lead time and the use of inventory to meet seasonal demand for products with limited shelf lives. Two fundamental questions are answered: 1) Under what conditions will an increase in product life lead to increased ability to meet demand? 2) Under what conditions will increased levels of starting inventory be beneficial? The results of this analysis assisted a plastics manufacturing firm in making product pricing and inventory decisions. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44 : 473–483, 1997     

空中预警机

本文说明什么是空中预警机,它在战争中的作用,以及E-2C 空中预警机的特点。详细叙述了E-3A 的六个航空电子设备分系统和空中预警机的发展趋势。     

The Blind Basinet: A New Interpretation of Royal Armouries IV.2

For many years a curiosity in the collection of the Royal Armouries, IV.2, or the ‘Blind Basinet’, is a fascinating example of an early 16th century great basinet not so much for what is present but for what is not. The lack of any means of seeing out of the helmet has led to a number of traditions regarding its provenance and purpose. A detailed examination of the helmet’s interior, as well as comparison with some other contemporary pieces, shows that it is an unfinished piece of armour. It was left at the stage where the sights and breaths would have been pierced, but they were left unfinished until some later modifications created a display piece, one which can still be seen at the Royal Armouries in Leeds.