网络机房制冷效率研究

根据相关的调查显示,在传统观念和设计标准的影响下,网络机房存在各种各样的设计缺陷,其中的一些缺陷会导致网络机房内部空间形成热点、降低制冷容错能力、制冷效率和制冷量,从而提高运行成本。网络机房的制冷效率和运行成本的大幅提高成为制约发展的重要因素。文章从网络机房面临的实际问题出发,有针对性地分析了机房设计的典型错误,阐述了其原理和影响,并根据实践经验,介绍了一些简单可行的解决方案。     

Surface integrity of Inconel 718 by hybrid selective laser melting and milling

ABSTRACT

While selective laser melting (SLM) offers design freedom of metal parts with much less material consumption, there exist several limitations, including high surface roughness, low-dimensional accuracy, and high tensile residual stresses. To make functional parts with high form accuracy and superior surface integrity, an as-SLM part needs finishing to remove the deposited surface material. The integration of machining and SLM creates a hybrid manufacturing route to overcome the inherited limitations of SLM. However, little study has been done to characterise surface integrity of an as-SLM part followed by machining (e.g. hybrid SLM-milling). In this paper, surface, integrity including surface roughness, microstructure, and microhardness, have been characterised for IN718 samples processed by the hybrid process. It has been found that microhardness varies with the scan direction and the use of coolant in the subsequent milling, and surface integrity can be significantly improved by the hybrid SLM-milling route.     

三角片离散法实现数控铣床加工仿真

三角片离散法是根据三轴数控铣床加工中的特点提出的加工仿真方法。文中结合笔者在微机上制作仿真软件的经验,使用三角片离散法实现数控铣床加工仿真;并详细地介绍了三角片离散法的原理、简化模型、计算方法以及提高效率的途径。该方法简单易行,而且有很好的真实感效果。     

三弧段型面联接的数控加工

论述了三弧段型面曲线的形成及其曲线参数方程,编制了三弧段型面的数控加工宏程序,适用于各种不同参数的三弧段型面的加工,且能够满足加工精度的要求。     

高强度放电灯电子镇流器在城市照明中的应用

本文介绍了HID电子镇流器在城市照明中的节能应用。     

电弧炉炼钢节电技术

电弧炉炼钢以消耗电能为主，电耗在钢成本中占很高比例，节电是降低成本的主要途径之一。本文分析了影响电弧炉炼钢电耗的主要因素，提出综合节电的技术措施。     

Heat regulating strategy in numerical control end milling for hard metal machining

The trend in die/mold manufacturing at present is towards the hard machining at high speed to replace the electron discharge machining. Failure forms of the A1TiN-coated micro-grain carbide endmill when used for the machining of/IS SKD61 (HRC 53), a widely used material in die/mold manufacturing, are investigated. The endmill shows a characteristic that tool life decreases greatly due to the chipping when overload occurs or the rapid increase of wear when over-heat accumulation in cutting edges. As a consequence of the investigation, a strategy to regulate heat generation in the end milling process is proposed. This is accomplished by controlling the cutting arc length, i.e. the length of each flute engaging workpiece in a cutting cycle. Case studies on the slot end milling and comer rounding are conducted. The results show that the proposed strategy suggests the optimal tool path as well as the optimal pitch between successive tool paths under the cutting time criterion.     

火电厂锅炉火用损失大不等于节能潜力大

本文通过对电厂锅炉火用损失的进一步分析计算，认为现有锅炉火用损失之大部分是不可避免的，“锅炉火用效率可以大幅度提高”的观点是不切实际的。文章对火电厂节能工作具有一定的指导作用。     

基于微放电加工元件轮廓测量的探针制造

为了推动微加工和微机械技术的进步，微型零件轮廓和尺度测量方法的发展非常重要．可行方法之一就是使用带微探头的小型三维轮廓测量仪．这种仪器的探头必须针对某个零件的测量，按照最佳外形制造．微放电加工有着极小加工力，可用于各种探头的制造，本研究中用它进行探头加工．用这种方法制造了多种探头，将其装在基于扫瞄隧道显微技术(STM)的小型三维轮廓测量仪上．所制造的探头已被成功地用于各种微元件测量，结果表明此方法可行．     

轮胎硫化留存内压过热水回收改造

轮胎硫化留存内压过热水回收是在轮胎正硫化结束后，切断内压过热水，将硫化胶囊内留存的携有大量热能的内压过热水，利用后一步序的内冷水顶出，直接回收到热水加热除氧器内，作为除氧器的补水，循环使用．银川佳通公司自行研究开发了该技术，于2003年10月开始分批实施，2004年2月完成全部改造．该项目涉及该公司5套除氧系统、98台个体硫化机及27台硫化罐，敷设主支管道1850m。控制阀组126套(接入硫化控制柜PLC控制)．经过实践检验，实施该技术后，除氧器耗汽量降低了30％～40％．内压系统压力、温度波动降低了15％．轮胎硫化留存热水回收达到国内同行业先进水平，经济效益比较显著。推广应用前景较好．