电潜泵中压变频调速系统的改进

电潜泵中压变频器输出端产生高次谐波和脉冲电流 ,对电潜泵电动机的绝缘性能和轴承寿命造成不利影响。为此 ,提出 3项改进对策 :①采用谐振软性开关逆变电路 ,使功率开关器件在零电压条件下导通 ;②在变频器逆变输出端设置电抗滤波器抑制高次谐波电流 ;③改变电动机内部结构 ,如加大定子槽宽 ,增加转子导条尺寸 ,变星接法为星 角接法 ,采用绝缘轴承等。实践证明 ,采取改进对策后 ,不仅提高了电潜泵的产量 ,而且变频器滤波后电动机端的过电压明显减小 ,电潜泵和电缆的寿命延长     

基于BOOSt结构下不连续导电模式的PFC电路

采用现代高频功率变换技术的有源功率因数校正（Power Factor Corrector,PFC)技术是解决高频开关变换器谐波污染的有效手段。与传统的PFC电路相比，有源PFC电路的输入电流接近正弦波且与输与电压同相位，能有效抑制电流波形畸变和谐波，因此避免了对同一电网设施的干扰。在PFC电路中，Boost变换器是研究和应用得最多的一种变换器。本文着重分析了Boost电路在不连续导电模式状态下，PFC电路的临界条件，对实际电路结构的设计有很好的指导意义。     

VLSI Implementation of Forward Error Control Technique for ATM Networks

In asynchronous transfer mode (ATM) networks, fixed length cells of 53 bytes are transmitted. A cell may be discarded during transmission due to buffer overflow or a detection of errors. Cell discarding seriously degrades transmission quality. The quality degradation can be reduced by employing efficient forward error control (FEC) to recover discarded cells. In this paper, we present the design and implementation of decoding equipment for FEC in ATM networks based on a single parity check (SPC) product code using very‐large‐scale integration (VLSI) technology. FEC allows the destination to reconstruct missing data cells by using redundant parity cells that the source adds to each block of data cells. The functionality of the design has been tested using the Model Sim 5.7cXE Simulation Package. The design has been implemented for a 5 ° 5 matrix of data cells in a Virtex‐E XCV 3200E FG1156 device. The simulation and synthesis results show that the decoding function can be completed in 81 clock cycles with an optimum clock of 56.8 MHz. A test bench was written to study the performance of the decoder, and the results are presented.     

挡渣球和挡渣塞技术在转炉炼钢的应用

介绍了档渣球和挡渣塞技术在转炉炼钢的实际应用，有利于降低原材料消耗、增加企业效益。     

A versatile data acquisition system for time resolved X-ray scattering using gas proportional detectors with delay line readout

A data acquisition system for time resolved X-ray scattering experiments using linear, quadrant or area gas proportional detectors with delay line readout based on commercially available hardware (National Instruments) is described. The system can easily be configured for recording data from point detectors (e.g. photomultipliers and photodiodes) and/or ancillary data only. Applications involving measurements with two different types of time to digital converters illustrate the features and performances of the system.     

湘钢80 t转炉工艺改进、产能提升的实践

介绍了湘潭钢铁集团有限公司3座80 t转炉通过改进装入制度、实行少渣量操作、控制炉型、优化生产工序等,实现了由日产7 000 t到10 000 t的产能提升,转炉作业率达84.22 %,冶炼品种钢比例达85.69 %.     

裂缝各向异性介质中P-SV转换波正演模拟

裂缝介质正演是研究裂缝性油藏的各向异性、裂缝检测方法、裂缝AVO反演等的前提。在裂缝方位各向异性(EDA)介质模型的基础上，重点研究了纵波震源激发的地震波所产生P-SV波的有限差分正演模拟方法。从各向异性单斜对称系统的刚性矩阵推导出的波动方程，可以满足EDA介质模型不同方位角入射的二维差分模拟要求。在有限差分模拟中，采用了普通的Kelly差分格式、二阶各向异性吸收边界条件和一般的纵波震源的解析形式，并应用修正的通量传输校(FCT)方法来消除频散。同时，对纵波震源的解析式进行了技术处理，取得了较好的效果。     

一种基于新型寄存器结构的逐次逼近A/D转换器

介绍了一种10位CMOS逐次逼近型A/D转换器。在25 kSPS采样频率以下,根据模拟输入端输入的0~10 V模拟信号,通过逐次逼近逻辑,将其转化为10位无极性数字码。转换器的SAR寄存器结构采用了一种新的结构来实现D触发器。该转换器采用3μm CMOS工艺制作,信噪比为49 dB,积分非线性为±0.5 LSB。     

宽带固定增益放大器THS4302特性及应用

THS4302是TI公司推出的新型固定增益放大器，具有2.4GHz的带宽和 5V／V的固定增益。其性能是现有同类产品的四倍，可为高速应用系统提供高速低噪声的模拟解决方案。文中介绍了THS4302的特点、工作原理及使用注意事项，并在此基础上给出了几种典型应用。     

320×240 Pixels CMOS Digital Image Sensor with Wide Dynamic Range

A 320×240 CMOS image sensor is demonstrated,which is implemented by a standard 0.6 μm 2P2M CMOS process.For reducing the chip area,each 2×2-pixel block shares a sample/hold circuit,analog-to-digital converter and 1-b memory.The 2×2 pixel pitch has an area of 40 μm×40 μm and the fill factor is about 16%.While operating at a low frame rate,the sensor dissipates a very low power by power-management circuit making pixel-level comparators in an idle state.A digital correlated double sampling,which eliminates fixed pattern noise,improves SNR of the sensor, and multiple sampling operations make the sensor have a wide dynamic range.