地铁车站基坑降水及排水施工技术

当前时期,国内的基建速度不断增快,城镇化历程快速增进,在地铁工程建设过程中,深基坑降排水施工技术是十分关键的因素,深基坑降排水施工技术与工程建造品质、施工活动的安全程度有特别紧密的联系,是项目保质保量完工的保障,是风险事件发生概率下降的重要举措,地铁深基坑降排水在近几年的发展过程中不断提高与完善,支护等技术逐步提高,与...     

锂离子电池多孔碳纳米材料的绿色制备及其性能研究

目前,锂离子电池电极材料的可选择性较多,其中多孔碳纳米材料由于其出色的性能而被广泛采用.虽然多孔碳纳米材料综合性能较为突出,但是在制备过程中二氧化碳(CO2)等温室气体排放是不可避免的.为实现多孔碳纳米材料绿色制备,本文提出了加热诱导氢化钙(CaH2)吸收二氧化碳(CO2)的方法制备出多孔碳纳米材料,同时对其性能进行了...     

Effects of Carbon Content and Solidification Rate on the Thermal Conductivity of Grey Cast Iron

The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimilar cooling rates. The cooling rates together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent, and the fraction of the former primary solidified austenite transformed into pearlite. The results show that the optimal thermal transport properties are obtained at medium cooling rates. Equations are given for the thermal conductivity of pearlite, solidified as pre-eutectic austenite, and the eutectic of grey iron. The thermal conductivity of pearlitic grey iron is modelled at both room temperature and elevated temperatures with good accuracy.     

针织提花关键技术及发展趋势

针对国内外针织提花技术的现状及发展趋势,结合针织提花技术在电脑提花大圆机上的关键技术展开讨论,提出实现高速、高可靠性的针织提花技术的基础研究方法,在此基础上本文结合电脑提花大圆机核心技术,研制了一种新型压电材料,建立了真彩图像色纱降阶模型和提花花型数据转换算法,并对在线纱线张力自动检测等关键技术进行研究与探讨.文中还简要介绍一种新型的针织机械电织提花大圆机的原理、控制理论与热设计研究方案.本文涉及到的基本原理、方法及思想对正在探索针织提花技术关键技术研究有重要的参考和指导作用.     

碳硫硅酸钙型硫酸盐侵蚀测试方法

碳硫硅酸钙和钙矾石有着很相似的晶体结构及形貌,常规测试中容易将二者混淆.在分析二者物相结构的基础上,介绍和评价了电子显微分析和成分分析、X射线衍射分析、红外和拉曼光谱分析、热分析、核磁共振等测试方法在碳硫硅酸钙型硫酸盐侵蚀研究中的应用特点和不足.电子显微分析和成分分析的结合以及单一的热分析能初步判定腐蚀产物中碳硫硅酸钙的存在,X射线衍射分析很难区分二者,红外、拉曼光谱以及核磁共振能确定硅氧八面体的存在,从而证明存在碳硫硅酸钙,因此研究中宜采用多种测试方法.     

Y_(5132C)插齿机刀轴的裂纹分析与控制

插齿机刀轴常出现裂纹。本文探讨出现裂纹的原因,认为是热处理淬火后压力校直时压下力过大所致。在刀轴 C—N 共渗时将立装改为吊装,并控制校直压力后,未再出现裂纹。     

Field Emission of SiCN Thin Films Bombarded by Ar^＋ Ions

SiCN thin films were synthesized by a radio frequency chemical vapor deposition (RFCVD) system on P-type Si (1 0 0) wafers using C2H4, SiH4 and N2 as raw materials.In order to get rid of the oxygen absorbed on the surface and improve the characteristics of electron field emission, Ax^ ions of low energy were used to bombard the samples. The field emission characteristics of SiCN thin films before and after Ar^ bombardment were studied in the super vacuum environment of 10^-6 Pa. It was showed that the turn-on field (defined as the point where the current-voltage curve shows a sharp increase in the current density) decreased from 38 V/μm before bombardment to 25 V/μm after bombardment. And the maximum emission current density increased from 159. 2 to 267. 4 μA/cm^2. The composition before and after Ar^ bombardment was compared using X-ray photoelec-tron spectroscopy (XPS). Our results illustrated that the field emission characteristics were improved after the bombardment of Ar^ .     

Fe—C马氏体室温时效转变的研究I—有序化

利用透射电镜对Ｆｅ－１．８３Ｃ马氏体室温时效所产生的有序化进行了详细的研究。结果表明：铁碳马氏体的有序相有两种，一种是具有Ｆｅ４Ｎ结构的普通有序相γ＇－ＦｅｘＣ（Ｉ），另一种是由它衍生出来的长周期有序相，称为γ＇－ＦｅｘＣ（ＩＩ），ｘ＝４－１０，两种有序相同时存在于马氏体的时效组织中，经研究确定的有序相晶体结构可以解释所有的实验衍射结果。