一个面积和功耗优化且适用于10/100 Base-T以太网的CMOS时钟恢复电路

提出了一个新的用于10 / 10 0 Base- T以太网中面积和功耗优化的时钟恢复电路.它采用双环路的结构,加快了锁相环路的捕获和跟踪速度;采用复用的方式,通过选择信号控制电路可分别在10 Mbps或10 0 Mbps模式下独立工作且能方便地实现模式间的互换,与采用两个独立的CDR电路相比节省了一半的面积;同时,电路中采用一般的延迟单元来取代DL L,并能保证环路性能不随工艺温度等条件引起的延迟单元、延迟时间的变化而变化,从而节省了功耗.Hspice模拟结果显示,在Vdd=2 .5 V时,10 0 Mbps模式下电路的功耗约为75 m W,稳态相差为0 .3 ns;10 Mbps模式时电路功耗为5 8m W     

对聚合物驱单井效果评价的几点认识

通过对喇嘛甸油田聚合物驱单井效果分析，给出了采油井阶段效果评价方法，即单井见效时间和含水回升时间早晚的确定方法，单井见效时间取决于油层条件，注聚前含油饱和度及累计采出地下体积倍数，单井含水回升时间主要取决于聚驱阶段剩余储量采出程度，根据单井阶段评价结果，对试验区进行跟踪调整，在单井阶段效果评价的基础上，对单井最终效果采用吨聚增油量和聚驱阶段剩余储量采收率来进行客观，有效的评价，对聚驱产量预测具有一定指导意义。     

Acid-base equilibrium—A thermodynamic study of formation and stability of the Bi-2223 phase

A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid-base theory, and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in. the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi³⁺; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase.     

Gradient Boundary Detection for Time Series Snapshot Construction in Sensor Networks

In many applications of sensor networks, the sink needs to keep track of the history of sensed data of a monitored region for scientific analysis or supporting historical queries. We call these historical data a time series of value distributions or snapshots. Obviously, to build the time series snapshots by requiring all of the sensors to transmit their data to the sink periodically is not energy efficient. In this paper, we introduce the idea of gradient boundary and propose the gradient boundary detection (GBD) algorithm to construct these time series snapshots of a monitored region. In GBD, a monitored region is partitioned into a set of subregions and all sensed data in one subregion are within a predefined value range, namely, the gradient interval. Sensors located on the boundaries of the subregions are required to transmit the data to the sink and, then, the sink recovers all subregions to construct snapshots of the monitored area. In this process, only the boundary sensors transmit their data and, therefore, energy consumption is greatly reduced. The simulation results show that GBD is able to build snapshots with a comparable accuracy and has up to 40 percent energy savings compared with the existing approaches for large gradient intervals.     

计算机支持的技术支援:概念与网络体系结构

首次提出了计算机支持的技术支援（CSTA）概念。计算机支持的技术支援是信息社会中技术支援的主要形式。分析了技术支援的过程、CSTA的技术特点和优点．总结了CSTA的基本研究内容和常用形式。针对技术支援的新需求、介绍了基于P2P的CSTA网络体系结构。     

Globally valid adaptive controllers of mechanical systems

The adaptive controller design of a large class of mechanical systems is addressed in this paper. The configuration space for the attitude of a vehicle is modelled as SO(3), namely the rotation matrix group. To avoid singularity problems, some studies adopt the representation of unit quaternions for modeling system dynamics and for the design of controllers. However, the complicated formulation of quatrains makes the application of this method limited to simple mechanical systems. Here, the strategy is to carry out the modeling and analysis in terms of the global representations of jet bundles of SO(3), while the unit quaternion is chosen to implement the controller for its least number of parameters (four) to represent SO(3) globally. Based on the transformation between the rotation matrix and the quaternion, the method explored in this paper gives rise to an adaptive controller in a clean and efficient way     

橡胶挤出机平均温差分析与计算

从理论上推导挤出机平均温差的计算公式，并指出与一般换热器平均温差计算的异同。     

基于TCP／IP的水利试验测控系统设计

本文介绍一种基于TCP／1P协议的新型水力物理模型试验测控系统，该系统将目前最先进、最流行的工业以太网技术应用到物理模型试验研究的测控系统中，实现多点水位、流速和流量等水力学重要参数的实时采集、处理、储存、显示及打印，并具有在线查询及数据分析功能。