新发现《卷洞桥彝汉文功德碑》初考

《卷洞桥彝汉文功德碑》系新发现文物,结合历史、地理、民族、民间传说特别是彝文文献、汉文史志的记载初步考证,此碑刻立的时间上限是明朝,下限是清朝咸丰十年,极有可能是明朝修建卷洞桥时刻立。此碑具有历史、文化、民族关系等多方面的较高的研究价值。     

基于ATmegal6的新型智能直流高压电源的设计

高压直流电源在科学实验和工业生产中有着广泛的运用,传统高压电源一般采用线性技术,普遍存在精度低、调整复杂、纹波系数大等诸多缺陷。为满足高压电源小型化、智能化、数字化的要求,文章主要介绍了一种基于ATmegal6为控制核心的数字化直流高压电源的设计方法。     

对河姆渡五叶纹陶块的思考

河姆渡遗址中发现的五叶纹陶块应该是河姆渡人祈求地神得到丰收的图像，其产生根源应与该地区内地理环境和农业发展有密切关系。     

整流电路智能故障诊断的一种新方法

介绍了一种采用BP神经网络对电力电子故障进行诊断方法。以三相整流电路为例，说明了神经网络采样样本的选取，以及输出与故障元之间的对应关系，实现了智能故障诊断。仿真结果证明该方法是有效可行的。     

利用新亚欧大陆桥优势发挥奎屯市在东联西出中的西桥头堡作用

在西部大开发中，奎屯市可利用其在第二亚欧大陆桥上的特殊位置，凭借有利的内外部条件，实施东联西出战略。     

Application of Single—to—Single Phase Matrix Conversion in Conventional Rectifier—Inverter

The principkle of Single-to-single phase matrix electric power conversion is further studied and the conversioin swith function is introduced into conventional rectifier-inverter,thus a general character of the two conversion techniques is discovered.It is characteristic of the switch functiion to follow mains voltage distrotion and mains frequency drift,By utilizing the merit,unidrectional switch duty-rations of the inverter follow the variation of DC-link voltage automatically,thus the size of DC-link electrolytic capacitor can be redued considerably,bringing about improved mains side power factor.Corresponding topologies and theoretical and theotor can be reduced considerably,bringing about improved mains side power factor,Corresponding topologies and theortical and theoretical derivations are given,and so are the simulation results,based on which it is confirmed that the single-to-single phase matrix conversion technique is potentially useful in large scale production,and the introduction of switch function can yield good economic returns.     

高功率因数的调宽式开关整流器

介绍一种新的单相开关整流器的控制方案,它采用有源电流波形整形技术来控制输入电流连续导通,其控制开关的周期是固定的,导通时间的大小是根据输入电流的斜率进行调控。论述该控制方案具有不需要电流传感器、线路功率因数高、电路简单等特点。理论分析和实验结果证明了该控制方案是可行的。     

论《板桥杂记》对青楼文化的重新审视

余怀的《板桥杂记》以纤巧绮丽的文字极力渲染了晚明时期秦淮河畔的繁华风月。透过这层薄纱,我们可依稀辨出余怀对青楼文化的重新审视。本文试从叙述意图、叙述对象、叙述手法、叙述价值四个方面对《板桥杂记》所体现的青楼文化进行深层次解读。     

Soft Switched Synchronous Rectifier with Phase-Shifted Full Bridge Converter and Its Small-Signal Analysis

BY USING THE OUTPUT INDUCTORS AND BODY CAPACITANCES WITHOUT ADDING ANY COMPONENT COMPARED WITH HARD SWITCHING SYNCHRONOUS RECTIFIER,THE TOPOLOGY OF A SOFT SWITCHED SYNCHRONOUS RECTIFIER WITH PHASE-SHIFTED FULL BRIDGE ZERO VOLTAGE SWITCHING DC/DC CONVERTER IS PROPOSED. THE CONVERTER EFFICIENCY IS MAXIMIZED DUE TO SOFT SWITCHING OF THE FULL BRIDGE MOSFETS AND THE SYNCHRONOUS MOS-FETS, AND ALSO THE LOW CONDUCTION LOSS OF SYNCHRONOUS MOSFET. THE OPERATION PRINCIPLES OF THE CIRCUIT ARE ANALYZED IN DETAIL AND THE SMALL-SIGNAL MODEL IS DERIVED, ALSO THE CONVERTER DYNAMIC CHARACTERISTICS ARE ANALYZED. FREQUENCY RESPONSES OF TRANSFER FUNCTIONS UNDER DIFFERENT VALUES OF TRANSFORMER PRIMARY LEAKAGE INDUCTANCE ARE DISCUSSED. THE EXPERIMENTAL RESULTS WERE OBTAINED FROM A 400 V INPUT AND 100 A/12 V OUTPUT DC/DC CONVERTER OPERATING AT 100 KHZ. THE RESULTS SHOW THAT THE CONVERTER EFFICIENCY IS 2% HIGHER IN RATED POWER THAN TRADITIONAL DIODE RECTIFIER.     

工科通识课程对大学生人文及科学精神培养的方法探索

文章以通识课程《道路桥梁工程导论》的教学为例,探索工科课程对学生人文及科学精神培养的方法。教学实践表明,学习历史有助于培养学生的民族自信心、时代责任感,勇于创新、学科融合等人文与科学精神。最后,提出一些更好地发挥教学效果的建议。