基于PRO/E三维管道轨迹专用检具的设计

介绍使用该软件组件设计模块中的高级工具———切除 (CutOut)功能设计高精度三维轨迹管道零件检具的方法 ,该方法具有高效和精密等特点。     

High-temperature hydrothermal systems in West Yunnan Province, China

There are more than 660 thermal springs in West Yunnan Province, 30 of which are high-temperature hydrothermal systems with reservoir temperatures above 150°C.All thermal springs in West Yunnan are under the control of the tectonics, most of them being distributed at anticlinoria of metamorphic rocks and granites. This paper discusses the relationship between thermal areas and tectonics, the correlation between thermal springs in West Yunnan and North Thailand, and the geothermal prospects in West Yunnan.     

Impact of nonuniform graded dopant profile in polysilicon gate on gate leakage current

In a MOSFET, a nonuniform, graded vertical dopant profile in the polysilicon gate causes a potential drop at the polysilicon/oxide interface. In this paper, the effect of this potential drop on the gate leakage current has been evaluated for the first time. The extent of variations of this affected gate leakage current with gate oxide thickness, gate length, and gate and drain bias conditions have been assessed with device simulation for an nMOS at 0.13 /spl mu/m low-voltage process. The results provide a guideline to the severity of this effect from the point of view of device and circuit operation and standby power consumption.     

阶跃信号突变点检测的小波分析法

文章运用小波理论这种新的数学工具,对于由基本平稳的慢变信号和阶跃型突变信号线性组合而构成的这类信号,提出了一种以连续小波变换为主体的检测和分析方法。理论以及实例分析表明,这种方法对于阶跃型突变信号的检侧,是颇为有效的。     

Filtres microondes en microruban suspendu

The authors present the design and the development of integrated microwave filters using suspended substrate microstrip, a technology that provides many advantages. Through quasi-static approximation the propagation structure has been treated using integral equations solved with the method of moments. Thanks to this tool of analysis and to an accurate synthesis method, a series of bandpass filters have been designed and manufactured. The results presented validate the accuracy of our design method.     

WXJB—E型多点温度监测报警仪的研制

本文介绍了 WXJB—E 型多点温度监测报警仪的设计思想、基本原理、技术关键、技术指标及其功能。     

Efficient Group-Based Multimedia-on-Demand Service Delivery in Wireless Networks

Recently, an upsurge of interest has been observed in providing multimedia on-demand (MoD) services to mobile users over wireless networks. Nevertheless, due to the rapidly varying nature of mobile networks and the scarcity of radio resources, the commercial implementation is still limited. This paper presents an efficient group-based multimedia-on-demand (GMoD) service model over multicast-enabled wireless infrastructures, where users requesting the same content are grouped and served simultaneously with a single multicast stream. The grouping is fulfilled through a process named "batching". An analytical model is derived to analyse a timeout-based batching scheme with respect to the tradeoff between user blocking probability and reneging probability. Based on the deduced analytical model, an optimal timeout-based batching scheme is proposed to dynamically identify the optimal tradeoff point that maximizes the system satisfaction ratio given a particular system status. The proposed scheme is evaluated by means of simulation and compared with two basic batching schemes (timeout-based, size-based), and two hybrid ones (combined-for-profit, combined-for-loss). The simulation results demonstrate the proposed approach can ensure significant gains in terms of user satisfaction ratio, with low reneging and blocking probabilities     

工字梁的抗剪极限承载力

对工字梁腹板抗剪极限承载力的研究进行总结,对各种公式与文献中的试验结果进行对比,将拉力场理论和转向应力场理论的假定与ANSYS分析揭示的腹板应力发展变化规律进行对比,指出了假定和数值分析结果的不一致。提出了翼缘对腹板转动约束的合理参数,得到精度良好的考虑翼缘约束的腹板剪切屈曲系数。利用得到的屈曲系数,考虑翼缘抗弯承载力的贡献,提出新的工字梁抗剪极限承载力的计算公式。与现有试验数据和ANSYS非线性有限元分析结果的对比,证实建议方法离散性较小,适用范围广,尤其是对于通用高厚比较大的梁,较以往方法有了较大改进。     

射流泵流场数值模拟的罚有限元法

本文采用罚函数有限元法,在标准k-ε双方程紊流模型下,对射流泵内部轴对称流场进行了数值模拟,得到了较全面的参数分布,特别是全场的压力分布,为射流泵的理论研究和优化设计提供了可靠的依据。给出的算例说明了与文献提供的实验结果基本一致。计算方法简捷,有较大的实用价值。