亚共晶高铬白口铸铁不抗磨的原因

亚共晶高铬白口铸铁显微组织中含有初晶奥氏体树枝晶，它得不到高硬度碳化物的良好保护。该合金试样的磨损面被磨料犁削的沟槽深而长。当热处理加热时，铸态初晶奥氏体含有过饱和的C和Cr，将以碳化物形式析出。为了平衡W（C）量和W（Cr）量，必须通过扩散析出碳化物。但在初晶奥氏体树枝晶中元素的扩散析出是很慢的，以致在通常实施的奥氏体保温时间内，远达不到平衡值，结果是初晶奥氏体具有低的Ms温度，使它含有较高的残余奥氏体。     

Characterization and optimization of a plasma doping process using a pulsed RF-excited B2H6 plasma system

The P+ plasma doping (PLAD) process using B₂H₆/H₂ plasma in a pulsed, RF-excited plasma system has been systematically characterized and optimized. The correlations between the deposition, retained B dose/profile, carrier dose/profile, sheet resistance (R_S) as a function of the pulse voltage, nominal dose, and carrier gas dilution have been extensively investigated. It was found that diluting B₂H₆ with H₂ can be used as a method to control and minimize boron deposition. SIMS and SRP analyses indicate that B and carrier profiles are deeper for higher dilutions up to 5/95 of a B₂H₆/H₂ gas ratio, than they are for lower dilutions due to less B deposition. This results in a higher activation fraction because of the B_SS limit and compensates for the reduction of the retained B dose. The higher dilutions also improved the retained B dose and R_S saturation due to less deposition. The PLAD process of a pulsed, RF-excited plasma system using B₂H₆ diluted with 92.5% to 95% H₂ was found to be an optimal condition for high-dose, boron-doping applications.     

电机防水方法的研究及应用

针对邯郸钢铁集团中板厂宽厚板产线辊道电机周围环境湿度较大，潮气进入电机内部使其绝缘受潮，造成烧损的问题，提出了对电机增设挡水罩、甩水轮、高压风管，以及提升电机现场管理和电机修理过程监控等措施。生产实践表明，全年可降低因电机造成的突发事故时间约20 h以上，每年可节约电机修理费用约10余万元，同时也减少了钢板表面质量缺陷，避免了质量异议的发生。     

基体预热温度对热障涂层热残余应力影响的研究

研究了用等离子喷涂工艺制备ZrO2-NiCrAl-LD-8基体的热障涂层过程中,基体预热温度对热障涂层热残余应力的影响.通过有限元计算分析,表明选择合适的基体温度,能大大降低热障涂层的热残余应力,为喷涂制备过程中基体预热温度的选择提供了参考.     

机床的静压系统及润滑

对机床的静压系统及其发展过程进行了综述 ,介绍了静压系统的基本结构、特点及其在机床中的各种运用。     

00Cr22Ni5Mo3N双相不锈钢热加工性能的试验研究

采用热压缩和热拉伸试验方法,对00Cr22Ni5Mo3N双相不锈钢的高温变形抗力、高温塑性以及在高温变形时的奥氏体相的数量进行了研究。试验结果表明,00Cr22Ni5Mo3N双相不锈钢的高温变形抗力和高温塑性较0Cr18Ni10Ti奥氏体不锈钢低,在1100～1250℃变形时,钢中奥氏体相的数量可以控制在适合热加工的范围,使钢具有较好的热加工性能。     

CCTV主楼延迟构件安装方法分析

CCTV主楼悬臂部分延迟构件的施工中采用了结构仿真技术,首先对延迟构件加固部分的安装和拆除时间进行计算选择,然后根据确定的安装和拆除时间,确定该工况下延迟构件加固的形式,根据现场的施工验证结构仿真结果.     

大体积混凝土施工技术

成都某商住楼工程底板为大体积混凝土工程.工程施工过程中,采用商品混凝土,其水灰比大,干缩变形大,混凝土浇筑正值当地天气较热的6月,这些增加了控制温度裂缝的难度.在具体施工过程中,通过采取严把材料关,避开日最高气温施工,确定合理的配合比等措施,成功地控制了混凝土裂缝的产生.     

位移反分析法的理论分析及工程应用

从分析岩体初始地应力场和进行地应力回归计算两方面探讨了位移反分析法的理论,通过工程算例说明了位移反分析法在工程中的应用,研究了位移反分析法的工程应用前景,以推广位移反分析法的应用。     

Optimal placement of metallic dampers for seismic upgrading of multistory buildings based on a cost‐effectiveness criterion using genetic algorithm

In this paper, an optimal placement methodology for metallic dampers is proposed to upgrade the seismic performance of multistory buildings. Most previous studies on optimal damper placement (ODP) problems have been focused on minimizing the seismic responses, whereas the present study aims to utilize the minimum total cost of dampers to achieve a prescribed level of seismic response. To this end, the optimization objective is constructed based on a cost‐effectiveness criterion, and the optimization constraint is defined based on a desired level of seismic response. An improved integer‐coded genetic algorithm is presented for solving the ODP problem. A 16‐story shear building is illustrated to verify the proposed optimal placement methodology. It is shown that the proposed methodology can be used to achieve the predetermined performance level while minimizing the retrofitting cost. Moreover, different algorithms, objective functions, and levels of accuracy on the optimization are also compared. Finally, a two‐step optimization approach is proposed for achieving better placement schemes with less computational efforts.