无人机发展应用及反无手段研究

近年来无人机及蜂群作战方式如火如荼,如何对抗无人机也成为近程防空重点.本文对无人机特点及分类,无人机作战方式及发展进行研究,深入分析了反无体系构成和手段,最后就反无系统中雷达的发展方向和任务提出建议.     

Effects of solder balls and arrays on the failure behavior in Package-on-Package structure

In this article, the failure behaviors of different solder balls and arrays used in a commercial produce were investigated experimentally and computationally. The results indicated that the effect of different solder balls and arrays on the failure behavior of Package-on-Package (PoP) structure cannot be ignored. For example, the failure mechanism of a structure with 2 × 15 solder balls could be characterized as a deformation-cracking-delamination model under axially tensile loading, while as a deformation-instability model under three-point bending loading. The allowable deformation of the former is ten times larger than that of the latter. In addition, the failure behavior for a structure with different solder balls and arrays varies. It is strongly dependent on the stiffness of PoP structure, which is dominated by the number and array of the solder balls. The relationship between the stiffness and the number appears nonlinear. More specifically, there is the maximum value for a structure.     

High Temperature Superconducting Magnetic Energy Storage and Its Power Control Technology

High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release scheme has been proposed and verified for developing a practical HTS SMES prototype.     

A PVT Tolerant 10 to 500 MHz All-Digital Phase-Locked Loop With Coupled TDC and DCO

An all-digital phase-locked loop (ADPLL) with all components working with time interval or period signals is demonstrated. The ADPLL consists mainly of a free-running ring oscillator (FRO), a time to digital converter (TDC), a digitally controlled oscillator (DCO), a digital divider and a digital loop filter. In the proposed architecture, the TDC and DCO have an equal time resolution from the common FRO. The digital divider keeps the loop gain constant when the frequency multiplication factor changes. As a result, the ADPLL is inherently stable regardless of the variations of the process, supply voltage and temperature (PVT). The ADPLL is fabricated in 0.13 $mu$m CMOS process. Measurement results show that it works well over wide operation conditions, with the input frequencies ranging from 37.5 KHz to 25 MHz, frequency multiplication factors from 10 to 255, output frequencies from 10 MHz to 500 MHz, and supply voltages from 0.6 V to 1.6 V.      

基于ART-2网络的自行火炮变速箱状态自适应分类

对于结构复杂的自行火炮变速箱，其故障模式具有不可预知性。针对传统的神经网络识别方法明显存在不足这一问题，提出一种基于自适应谐振理论（Adaptive Resonance Theory）的自行火炮变速箱瞬态过程故障诊断新方法。该方法不仅可以对已知的故障模式进行分类，而且对自行火炮变速箱未知故障模式具有很强的自适应分辨能力。实例证明，ART-2神经网络与传统的神经网络方法相结合为自行火炮变速箱故障诊断提出了新思路。     

基于LABVIEW的光收发模组的测试平台及测试分析

文章以光发射组件TOSA和光接收组件ROSA为主要硬件,LABVIEW7.0为软件开发测试平台,对已组装好的光收发模组的性能进行测试,并分析不同温度下的测试眼图和数据结果,完成测试任务。最后对测试中存在的问题进行了总结和展望。     

电信网络风险评估指标体系研究及应用

为评估电信网的风险,可通过分析风险与安全事件的关系,以安全事件的组成元素构建电信网的风险评估指标体系,并进行风险的分级量化.本文分析了电信网的风险模糊综合评估方法,并进行了实例计算.该方法可作为电信网风险评估的一种有效方法.     

Improvedn-type GaAs ohmic contacts compatible with a chlorine-based dry-etch process

We report the use of a Mo barrier layer within Ni/Au-Ge based ohmic contacts to GaAs for eliminating an etch stop reaction that occurs during Cl-based dry etching of heterojunction bipolar transistors. With conventional Ni/Au-Ge/Ag ohmic contacts, chlorinecontaining discharges produce a passivating layer of AgCl on the semiconductor surface, preventing further etching. This layer is absent when the Ag in the contact is replaced with Mo. The Mo has several advantages over other diffusion barrier layers and yields contacts with excellent adhesion, smooth morphology, and sharp edge definition. The average contact resistivity of these contacts ton ⁺-GaAs(n = 6 × 10¹⁸ cm^-3) was 0.074 ohm-mm, which is lower than the typical contact resistivity of conventional Ni/Au-Ge/ Ag metallization (0.11 ohm-mm).     

对引进离子注入机损坏部件进行国产化替换的尝试

国内引进了不少离子注入机,维修问题日渐重要。对其损坏部件,用国产配件进行替换,不乏为又快又省的维修方法。本文叙述了八年多来,我们在维修IM—200M型离子注入机的实践中,对损坏的吸极电源、氟里昂热交换器和化学机械泵等重要部件,用自制的或改制的国内配件进行替换,从而保证了设备安全运行二万五千多小时,注入八万五千多块硅及GaAs靶片,完成了集成电路研制和开发任务。     

Mobile Cloud Computing: A Survey,State of Art and Future Directions

In the recent years, cloud computing frameworks such as Amazon Web Services, Google AppEngine and Windows Azure have become increasingly popular among IT organizations and developers. Simultaneously, we have seen a phenomenal increase in the usage and deployment of smartphone platforms and applications worldwide. This paper discusses the current state of the art in the merger of these two popular technologies, that we refer to as Mobile Cloud Computing (MCC). We illustrate the applicability of MCC in various domains including mobile learning, commerce, health/wellness and social medias. We further identify research gaps covering critical aspects of how MCC can be realized and effectively utilized at scale. These include improved resource allocation in the MCC environment through efficient task distribution and offloading, security and privacy.