某地区“十一五”电网规划后评估

通过对某地区的“十一五”电网规划现状实施情况的分析,提出了一系列规划后评估的指标体系,并根据该地区所提供的数据对其进行规划后评估,最后对该地区的“十一五”电网规划作出客观的评估。     

论骨质瓷的坯釉适应性

骨质瓷通常采用高温素烧、低温釉烧二次烧成工艺,其坯釉料组成和生产工艺存在复杂性,在制备过程中,常因坯釉的不适应而影响其性能和釉面质量。本文从四个方面论述了骨质瓷坯釉适应性的影响因素,并提出改善途径。     

Fundamental investigations on the material flow at combined sheet and bulk metal forming processes

The class of combined sheet and bulk metal forming (SBMF) processes denotes the forming of sheet metals with typical bulk forming operations. As a consequence, simultaneous 2D and 3D stress and strain states are present. Furthermore the local shape elements formed out of the sheet plane are in the magnitude of the sheet thickness. This paper deals with process combinations upsetting/lateral extrusion and deep drawing/upsetting. It has been shown that an insufficient mould filling is nearly inevitable using conventional tooling systems. Hence, the prospect of newly developed forming approaches will be discussed.     

工艺参数对镁合金铸轧板坯凝固前沿影响规律的研究

通过镁合金铸轧工艺试验,分析了辊面线速度、轧辊直径、铸轧区长度以及铸轧板坯厚度对铸轧区凝固前沿位置及板坯宏观质量的影响。试验结果表明,在铸轧区长度、板坯厚度一定的条件下,铸轧速度显著影响凝固前沿位置,并进一步决定镁合金铸轧板坯表面质量及宏观缺陷形成特征。在其他工况条件不变的情况下,铸轧速度必须根据铸轧区长度、板坯厚度进行调整,并将铸轧区凝固前沿控制在优化区域,可稳定工艺、提高板坯的表面质量。     

熔体处理温度对自孕育法制备AZ61半固态浆料的影响

采用自孕育法制备AZ61变形镁合金半固态浆料,研究了熔体处理温度对制备AZ61变形镁合金半固态浆料的影响。结果表明,自孕育铸造法制备AZ61半固态浆料在液相线以下凝固成形,可以获得近球状的初生相。适宜的熔体处理温度为700℃,对应的平均晶粒尺寸为39.8μm。熔体处理温度过低时,组织中的树枝晶减少的同时细小的近球状晶增多,但是其晶粒尺寸大小分布不均匀。熔体处理温度过高时,组织中树枝晶增多,晶粒平均尺寸显著变大。     

采用CA-FE法模拟双辊连铸纯铝凝固微观组织

使用有限元软件Procast中的元胞自动机-有限元模型,建立了一个模拟双辊连续铸轧纯铝凝固微观组织形成的随机性模型.综合考虑了溶质再分配、界面曲率、晶粒择优生长的作用,基于有限元建立了宏观温度场计算和一个改进的元胞自动机模型.采用基于高斯分布的连续性形核模型,辊面和熔体内部的形核分别采用两种形核分布函数;枝晶尖端生长速度采用与局部过冷度有关的修正KGT模型.利用软件计算结果模拟了不同浇注温度和熔液内部平均形核过冷度对凝固微观组织形成的影响.     

发射机机房智能排风装置的设计与实现

为了提高发射机机房的排风冷却效果,采用ZigBee无线通信技术设计了发射机机房智能排风装置,系统由4个排风装置和1个监测主机组成.排风装置放在机房四面墙的顶部,通过传感器DS18B20探测窗外和窗内气体的温度,并用ZigBee模块CC2420发送至监测主机,监测主机对排风窗外的温度比较处理后,控制排风装置的风扇正反转,保证吸入冷气流,排出热气流.经实验表明,该智能排风装置能自动平衡机房内的气温,对于建立信息化和智能化的机房具有重要意义.     

An Engineer Asks: Is it Really More Important that Paint Stays Stuck on the Outside of an Aircraft than that Glue Stays Stuck on the Inside?

The purpose of this article is to draw attention to two problems encountered with modern aircraft: the difficulties in making adhesive and paint adhere to composite substrates and the lack of any after-the-fact inspection that can prove that there will not be any interfacial failures at some time during the service life. It is also observed that the response to paint peeling off is more rapid and thorough than to a discovery of separations between internal components that were once believed to have been bonded together. Because there is so much similarity between the processes of making paint and adhesive adhere, it is suggested that some of the efforts to improve adhesion of the paint might also help improve the processes for making adhesives stick. The article focuses on a series of anecdotes about problems and their resolutions, with the hope that the solutions might help others solve or avoid future such problems. It is pointed out that the cost of improving the adhesion of both paint and adhesive has always been insignificant in comparison with the sometimes enormous costs incurred as a result of fleet-wide occurrences of what were perceived to be bond “failures” but which should more properly be characterized as initially undetected nonbonds. A critical issue is the acknowledged absence of any nondestructive inspection capable of distinguishing between bonds that will “fail” in service and those that will not. Experience has shown that none of the apparent interfacial failures to date have occurred on grit-blasted surfaces. Equally, it must be conceded that not all of the bonded composite structures made using peel-ply surfaces can be expected to fail, even though those associated with released peel plies or prebond moisture probably will, because these conditions have been associated with so many of the past failures. The distinction between interfacial failures and impact damage to properly bonded structures is that the former can extend throughout the entire structure, whereas the broken fibers and interlaminar matrix failures associated with the latter will not extend far beyond the impact area. This is one reason why it is so important to use only surface preparations that ensure the absence of interfacial failures. It is also noted that there is no counterpart, for the bonding of composite structures, of the peel-type test that was so instrumental in solving the equivalent bonding problem that was widespread in bonded metal structures some 30 years ago. It is recommended that there should be, because the use of only shear-load tests has been found to be insufficient to ensure bond durability for both metallic and composite structures.     

多层板内层铜箔棕化处理液研制

文章概述了应用于PCB多层板制作过程中的棕化工艺原理及棕化膜的结构。主要讨论了一种新的棕化处理液,包括配方组成和工艺方法。经实验和应用实践证明,它具有能够显著促进铜面与粘结片的结合力,耐高温热冲击-陛能良好,抗剥离强度高,没有粉红圈,工艺流程简单,适用性广,成本低等特点。     

地区性河湖水系连通脆弱性评价方法及应用

在对河湖水系连通脆弱性分类基础上,指出河湖水系连通脆弱性扰动可分为本质脆弱性扰动、特殊脆弱性扰动,进而探讨了河湖水系连通脆弱性、敏感性和适应性三者之间的关系,构建了河湖水系连通脆弱性的敏感性指标体系,分析了河湖水系连通的适应性,提出了河湖水系连通脆弱性评价方法,并据此评价了辽宁省中部六城市地区的河湖水系连通脆弱性,指出该六城市群已处于河湖水系连通极脆弱区,亟需实施大伙房水库输水工程调水。