Profile-Driven Component Placement for Cluster-Based Online Services

The growth of the Internet and of various intranets has spawned a wealth of online services, most of which are implemented on local-area clusters using remote invocation (for example, remote procedure call/remote method invocation) among manually placed application components. Component placement can be a significant challenge for large-scale services, particularly when application resource needs are workload dependent. Automatic component placement has the potential to maximize overall system throughput. The key idea is to construct (offline) a mapping between input workload and individual-component resource consumption. Such mappings, called component profiles, then support high-performance placement. Preliminary results on an online auction benchmark based on J2EE (Java 2 Platform, Enterprise Edition) suggest that profile-driven tools can identify placements that achieve near-optimal overall throughput.     

Optical-transmission characteristics of optical-fiber cables and installed optical-fiber cable networks for WDM systems

Many cables containing 1.3-/spl mu/m zero-dispersion single-mode (SM) optical fibers are installed in trunk and access networks. Recently, there have been a number of studies on wavelength-division-multiplexing (WDM) systems designed to increase transmission capacity and flexibility. If we can construct WDM systems using SM optical-fiber cable networks designed to transmit using wavelengths in the 1.3-/spl mu/m window (O-band), this will prove very effective in reducing construction costs. It is therefore important to examine the wavelength dependence of the transmission characteristics of SM optical-fiber cables and networks that have already been installed and in which several optical fibers are joined. In this paper, we describe the measured optical characteristics of SM optical-fiber cables and installed optical-fiber cable networks at various wavelengths. The optical characteristics were stable in the 1.46 to 1.625-/spl mu/m wavelength range and we confirmed that the installed SM optical-fiber cable networks could be used for WDM system applications.     

火炮身管内表面激光硬化处理的实验研究

提高身管寿命是火炮行业亟待解决的关键技术问题，激光表面改性技术是解决这一问题的有效方法之一。本文在分析激光表面相变硬化性能的基础上，对身管内表面进行了激光硬化处理实验研究，检测了其内表面阳线和阴线的硬化层硬度和深度，对比分析了离焦量和焦深对其内表面硬化层硬度的影响，并对激光相变硬化层金相组织进行了分析。经激光硬化处理后，身管的内表面硬度有明显提高，硬化层较深，且为很细的条状马氏体组织。     

气测录井定量快速色谱分析技术

为了推动气测录井定量快速色谱分析技术在钻井现场广泛应用,该文从定量快速色谱与常规色谱的比较入手,在阐述定量快速色谱仪工作原理的基础上,探讨了定量快速色谱技术三个方面的优势——薄油气层的发现与评价、快速钻进条件下发现油气层以及加入钻井液添加剂条件下识别真假油气显示。相信随着定量快速色谱分析技术的应用,油气层发现与评价的准确率会得到很大提高。     

无油分子泵机组的组装

介绍了将ALCATEL公司生产的一台ATPl00涡轮分子泵、一台MDP50ll牵引分子泵及一台VRC公司生产的lBy6型干泵组装成无油分子泵机组的过程。文中给出了泵间配合的计算、机组方案的设计、连接管路、仪器支架的设计及选择。本机组所采取的设计方案使三个泵都最大限度地发挥了优点避免了缺陷，较好地满足了使用要求，为今后选购单泵和组装无油分子泵机组提供了可靠的理论和实验依据。     

Computational analysis of thin coating layer failure using a cohesive model and gradient plasticity

Thermal barrier coatings (TBC) are widely used to prevent transient high temperature attack and allow components high durability. Due to strong inhomogeneous material properties the TBC failure often initiates near the interface between the brittle oxide layer and the ductile substrate. A reliable prediction of the TBC failure requires detailed information about the crack tip field and the consequent fracture criteria. In the present paper both cohesive model and gradient plasticity are used to simulate the failure process and to study interdependence of the interface stress distribution with the specific fracture energies. Computations confirm that combination of the two models is able to simulate different failure mechanisms in the TBC system. The computational model has the potential to give a realistic prediction of the crack propagation process.     

自对准双扩散MOS器件的阈值电压分析

文章提出了精确描述自对准双扩散MOS器件阀值电压的解析模型，给出了其沟道中杂质的二维分布和源结耗尽层宽度的计算方法；分析了边缘效应对氧化层电容的影响，借助电荷共事模型，建立了反映非均匀沟道中耗尽层电荷变化及其对开启电压影响的阀值电压模型；同时，借助二维仿真器，计算出自对准双扩散MOS器件的阈值电压，其值与解析值相吻合。     

深井长裸眼跨隔测试新工艺的应用

为减少勘探费用，缩短施工周期，取全取准各项地质资料，采取中途测试工艺。随着深井中途测试不断增多，特别是跨隔支撑测试具有一定施工风险和难度，要求测试质量不断提高。结合油田生产实际，合理选配了地层测试工具仪表，不断改进测试管串和优化施工设计，经盐22井中途跨隔测试应用，获得成功。     

Mobility management architectures based on joint mobile IP and SIP protocols

In the all-IP wireless networks beyond the third generation, mobility management can be effectively achieved by applying mobile IP (MIP) and the session initiation protocol (SIP) jointly. Nevertheless, an efficient combination of both protocols remains an open research issue. Conventional hybrid MIP-SIP mobility architectures operate MIP and SIP almost independently, resulting in significant redundant costs. This article investigates the representative hybrid MIP-SIP architectures and explores the joint optimizations between MIP and SIP for a more cost-efficient mobility support whilst utilizing their complementary power. Two novel design approaches are presented. The first approach culminates in a tightly integrated architecture, which merges the redundant mobility entities in MIP and SIP to yield maximum system efficiency. The other approach leads to a loosely integrated architecture, where necessary interactions are introduced between MIP and SIP mobility servers while their physical entities are kept intact. Major mobility procedures, including location update, session setup and handoff, are discussed in these architectures. The analytical results demonstrate that both proposed architectures outperform typical hybrid MIP-SIP architectures in terms of clear-cut reduced signaling costs     

一种基于PWM的电压输出DAC电路设计

对实际应用中的脉宽调制(PWM)波形的频谱进行了理论分析．指出通过一个低通滤波器可以把PWM调制的数模转换信号解调出来．实现从PWM到DAC的转换。论文还对转换误差产生的因素进行了分析，指出了减少误差的方法，论文给出了两种从PWM到0～5V电压输出的电路实现方法，第2种电路具有很高的转换精度。