新型高效除草剂噻磺隆合成新工艺

介绍了以氯甲酸甲酯和2-羧甲基-3-磺酰氨基噻吩为起始原料合成除草剂噻磺隆的方法。原料2-羧甲基-3-磺酰氨基噻吩与氯甲酸甲酯生成2-甲氧羧基-3-磺酰氨基甲酸甲酯噻吩，再与2-氨基-4-甲氧基-6-甲基均三嗪反应生成噻磺隆。避免了异氰酸酯路线的种种缺点，具有收率高、含量高和成本低的特点。以2-羧甲基-3-磺酰氨基噻吩计，总收率为77．73％，原药纯度达到93．6％。     

开关电源新技术的应用研究

以功率MOSFET和IGBT为代表的、集高频、高压和大电流于一身的功率半导体复合器件,表明传统电力电子技术已经进入现代电力电子时代,开关电源的工作频率得以大大提高,一些新技术的应用更是进一步提升了开关电源的性能。开关电源拥有更广阔的发展空间和应用前景。     

基于JSP网上考试系统设计与实现

在线考试是近几年出现的一种新的考试形式,本文主要对在线考试系统进行分析、设计,并给出在Tom cat7.034+Jsp+Servlet+Javabean+SQLServer2005架构下,实现该系统的部分关键代码。     

Reinforcements affect mechanical properties and wear behaviors of WC clad layer by gas tungsten arc welding

This work deals with the surface analysis, mechanical properties and wear performances of the clad layer, which is made from tungsten carbide (WC) powders on SKD61 die steel by the gas tungsten arc welding method. According to the experimental results, due to the high hardness and elastic modulus reinforcements (Fe₃W₃C and M₇C₃) existing in the WC clad layer, the WC clad specimen has excellent wear performance at different sliding speeds.According to the wear analysis, wear behaviors of the WC clad layer are two-body abrasion and oxidation wear. In addition, oxidation wear dominates the wear behaviors of the SKD61 die steel specimen at different sliding speeds.     

基于喷油泵凸轮廓线建立从动件运动方程的研究

本文以16V240ZJB型柴油机为例,通过对喷油泵凸轮轮廓曲线进行几何分析,进行从动件升程段运动方程建立的研究。为喷油泵凸轮机构性能的进一步研究分析提供了必要的理论依据。     

基于PIC16F877单片机的加热炉模糊控制系统设计与研究

针对热处理加热炉具有大惯性、纯滞后等非线性时变的特点,基于精确数学模型的常规PID控制难以保证加热工艺要求。设计一种基于PIC16F877单片机的加热炉模糊控制系统,具有数据采集、炉温控制以及故障监测等功能,采用规则自寻优的控制算法进行过程控制,对该算法进行了深入的研究,从而实现了对整个加热过程的全自动智能控制。以某加热炉为对象用MATLAB进行了仿真,结果表明该系统控制精度高,超调量小,鲁棒性强,对工业加热炉的控制具有一定的推广价值。     

A focused review of the hydrogen storage tank embrittlement mechanism process

Hydrogen embrittlement is a widely known phenomenon in high-strength and storage materials. Hydrogen embrittlement is responsible for subcritical crack growth in material, fracture initiation, subsequent loss in mechanical properties, and catastrophic failure. Hydrogen is induced in the material during an electrochemical reaction between the hydrogen, storage materials, and high-pressure gaseous hydrogen environment. Various mechanisms which are responsible for crack development, growth, and fracture have been deliberated and reported. However, the fundamental mechanism of hydrogen embrittlement remains unclear. Several techniques such as linearly increasing stress test techniques (LIST), constant extension rate test (CERT) and slow strain rate testing (SSRT), thermal desorption spectroscopy (TDS), permeation testing (PT), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been utilized to determine the amount of hydrogen diffused and available in the hydrogen storage material. The review intends to categorize and provide a clear understanding of the degradation mechanism that occurs during hydrogen embrittlement. The improvement in mitigating the hydrogen embrittlement degradation as a function of modifying the structure and surfaces of the material is established. Prospects for addressing hydrogen embrittlement degradation through further experimental and numerical research are suggested. Lastly, this paper through recommendation endeavors to prevent hydrogen storage tank degradation and reduces high costs associated with the replacement of the component in renewable energy applications.     

CLK5162高速数控铣床横梁动态性能分析及优化

以CLK5162高速数控铣床的横梁为研究对象,使用SolidWorks软件对其进行实体建模,然后使用ANSYS软件对其进行模态分析,找出其薄弱环节并进行优化,改善了横梁的动态性能。     

Sm对时效态Mg-12Gd-2Y-0.5Zr合金组织与力学性能的影响

通过组织观察、拉伸试验和断口分析,研究了Mg-12Gd-2Y-（0,0.5,1.0,1.5）Sm-0.5Zr合金的显微组织和20～300℃下的力学性能。结果表明,随着Sm含量的增加,合金晶粒细化,屈服强度及高温抗拉强度显著提高。同时,随着温度的升高,合金的抗拉强度具有反常的温度效应。     

数控机床的数控系统故障诊断方法探析

数控系统是涉及多个应用学科的复杂系统,加之机床本身种类繁多,功能各异,结构风格也多种多样,数控系统故障诊断起来较为困难,为了解决这类问题,对一些常用的数控系统故障诊断技术作了介绍,以为机床维修人员提供有益的参考。