起爆环半径对多定向破片战斗部参数的影响

起爆方式对爆炸成型多定向破片（MDF）战斗部的形成过程和形态具有重要影响。在深刻理解MDF战斗部爆炸成型机理的基础上,通过对药型罩由切割网栅形成多个破片过程的仿真和爆轰波作用理论分析,研究了环起爆方式下起爆环半径对MDF战斗部参数的影响。研究表明：随着起爆环半径的增加,切割药型罩形成的MDF头部破片速度随之增大,但破片的剩余质量将会减小,而破片的发散角则随起爆环半径的增加呈现先增大再减小的趋势;对于特定的MDF战斗部,当起爆环半径在8～12 mm时,破片的侵彻能力和对目标的毁伤作用效果最好。     

面向等残余面形误差的分层修形模具气囊抛光轨迹规划方法

气囊抛光方法可成功应用于模具自由曲面,实现自动化抛光。提出一种面向等残余面形误差的分层修形模具气囊抛光轨迹规划新方法,该方法可用于等残余面形误差工件的整个面形修正过程或非等残余面形误差状态下气囊抛光工艺中的某一阶段。针对光栅型抛光轨迹给出一种基于一次去除深度函数数值仿真的驻留点间距优选方法,并设计了对比性实验进行验证。实验结果表明,以X方向为进给方向的光栅型轨迹中,驻留点间距值选择去除模型中最大去除量1/2处对应Y值的两倍是合理的。     

面罩壳体对显示屏效果的影响

随着LED显示屏控制技术和校正技术的发展,各厂家的显示效果优劣差距在进一步缩小,这个时候,显示屏外观结构件对其的影响就凸显起来,本文将从提高对比度、降低马赛克、增强耐候性三个方面来论述面罩、壳体的设计对LED显示屏在黑屏和亮屏时产生的不同影响。     

A Novel Quarter-Circular Arc Multi-Direction Piezo electric VEH and Its Theoretical Model

A quarter-circular arc piezoelectric Vibra-tion energy harvester (VEH) based on nonlinear geometry is proposed with both bending moment and torque deformation mode, so it can effectively absorb multi-directional vibration at the same resonance frequency. The theoretical model of quarter-circular arc piezoelectric VEH is established to study the resonance frequency and the output voltage. In order to demonstrate multi-directional performance of the quarter-circular arc VEH, the stress distribution is compared with that of the traditional piezoelectric VEH in multi-direction vibration, and the output voltage of the circular arc piezoelectric VEH are relatively increased 267.26％ in X-direction, 463.18％ in Y-direction, and 17.24％ in Z-direction. The external load is equipped in circuit to measure output power, whose matching resistance is around 21k?, and the maximum output powers are 7.57mW in X-direction, 2.39mW in Y-direction, and 9.93mW in Z-direction.     

新式激光假目标的研究与设计

针对现有激光假目标的适用条件与要地防空中使用时的受限之处,为提升激光诱饵作战效能,提出光纤激光诱饵、伴飞无人机两种激光假目标方式,从其概念、使用时机、特点、布设方法和载机、材料的选择几个方面进行分析探讨,研究了其特性与使用方法。     

Peer-to-peer electricity trading system: smart contracts based proof-of-benefit consensus protocol

Wireless Networks - Nowadays, people trade electricity through centralized companies or organizations which is vulnerable to cyber attacks and incapable of coping with increasing demands from...     

基于Parlay API的面向3G内容计费的研究

介绍了第三代移动通信网络中的业务开发技术-Parlay以及开放式接口API，详细分析了该技术的计费业务提供机制．在分析现有计费模式的不足的基础上，描述了内容计费的产生、需求及发展，介绍相关标准．重点研究了ParlayAPI规范中计费SCF（Service Capability Feature）在内容计费的3G计费平台中所提供的计费能力．针对WAP网页浏览业务，使用UML设计了基于流量的计费业务，给出了数据流分析示意图和计费流程．     

Research on the memory order of the power‐line communication channel

As a memory channel, power‐line communication (PLC) channel can be modeled by the finite states Morkov model. The memory order in an finite states Morkov model is a key parameter, which is not solved in PLC systems yet. In the paper, the mutual information is used as a measure of the dependence between the different symbols, treated as the received scalar network analyzer, or amplitude of the current channel symbol or that of previous symbols. The joint distribution probabilities of the envelopes in PLC systems are computed based on the multi‐path channel model, which is commonly used in PLC. With the first‐order Markovian assumption, we confirm that given the information of the symbol immediately preceding the current one, any other previous symbol is independent of the current one in PLC systems. The field test is also performed to model the received OFDM signals with the help of autoregressive model. The results show that the first‐order autoregressive model is enough to model the fading channel in PLC systems, which means the amount of uncertainty remaining in the current symbol should be negligible, given the information corresponding to the immediately preceding one. Copyright © 2014 John Wiley & Sons, Ltd.     

激光离子源离子迁移谱仪模拟研究

离子迁移谱技术(IMS)是一门新兴的化学分析技术,被广泛应用于测定痕量的化学武器、毒品、爆炸物,以及空气污染物等,跟其他的有机化合物分析仪器相比较,他具有体积小、灵敏度高、适用范围广、分析时间快,能在大气压和室温下工作等优点,是一种前景广阔的检测仪器。介绍了激光离子源IMS的工作原理、主要特点和仪器结构,利用软件SMION设计模拟激光离子源IMS,通过模拟实验得出真空状态下,信号接收盘半径与信号强度成正比关系,以及迁移管内的离子门开关电压阈值。     

一种宽带宽波束双圆极化天线设计

针对卫星移动通信系统,文中设计了一种新型圆极化微带天线。通过使用四臂“L”形探针、寄生层叠结构和带状线馈电网络实现了宽带、宽波束和双圆极化工作。对原理样机进行测试,结果表明,天线在20%的工作带宽内电压驻波比＜2.0∶[KG-2mm]1,轴比＜3.2 dB,3 dB波束宽度＞120°。