Isothermal precipitation behavior of copper sulfide in ultra low carbon steel

Copper and sulfur are typical residual elements or impurity elements in steel.Sufficient removal of them during steelmaking process is difficult for copper and costly for sulfur.Utilization of copper and sulfur in steel, especially in steel scrap,has been an important issue for a long period for metallurgists.Copper and sulfur may combine to form copper sulfide,which may provide a prospect to avoid the detrimental effects of copper and sulfur in steel.Unfortunately the formation mechanism of copper sulfide in steel has not been completely clarified so far. In the present paper,solution treatment of samples containing copper and sulfur are firstly performed at 1623 K for 2.7×10~3 s followed by quenching into water.The samples are then isothermally heat-treated at 673 K,873 K, 1073 K,1273 K and 1373K for different time followed by quenching into water again.The size,morphology, constituent and crystallography of sulfide precipitates in these samples are investigated by scanning electron microscope(SEM) and TEM equipped with EDS.Fine copper sulfides(less than 100 nm) are observed to coexist with silicon oxide in samples even isothermally heat-treated at 1 373 K for 1.44×10~4 s;Film-like copper sulfides are generally observed to co-exist with iron sulfide in all samples;Plate-like copper sulfides are observed especially in sample isothermally heat-treated at 1 073 K for 1.44×10~4 s.The formation mechanisms of these copper sulfides have been discussed.     

石家庄和平路高架桥防水施工技术

介绍了橡胶改性沥青防水涂料和无碱短纤维在石家庄和平路高架桥桥面防水工程中的应用,包括工程选用的防水材料、施工设备和具体的施工工艺.     

由几个水泥厂预均化堆场设计引发的思考

预均化堆场是水泥厂堆取生产用物料的车间,它的特点是占地面积广,投资较大,堆取料时容易造成大量扬尘,影响厂区环境。总结和吸取了国内外几个优秀项目经验,介绍了长形和圆形预均化堆场的布置形式和堆取料形式,比较了两种堆场的优劣,并且在增加有效储量和节省投资方面给出了一些思考和经验总结。     

关于离子阱频标

本文介绍了离子阱频标的原理、现状及前景，并给出了该频标与实验室型磁选态铯束频标，光抽运铯束频标及铯原子喷泉频标的性能比较。     

引滦输水枢纽工程信息系统建设构思

在概述引滦输水枢纽工程信息系统建设现状的基础上，阐明了信息系统的总体需求和建设目标，分析了系统应具有的总体构架，并叙述了构成引滦输水枢纽工程信息系统的各层支撑平台以及各类应用系统分别应具备的功能、组成、结构等内容。该系统的总体构架由9个应用平台、4层支撑平台、2类保障体系和1个对外服务平台组成。     

Progress of the NTSC-F1 primary frequency standard

The SI "second"is realized by caesium primary frequency standards( PFSs) using laser cooled atoms in a fountain configuration. Four sub systems and operation procedure of the NTSC-F1 primary frequency standard are introduced in the paper.The frequency stability of NTSC-F1 is 3.0×10-13/ τ-1 / 2compared to hydrogen maser. Four terms of frequency shift and uncertainty including second order Zeeman frequency shift,cold collision shift,gravity shift and blackbody shift are evaluated. The improvement of NTSC-F1 is introduced.     

The investigation on sensitive mapping of memory cell in microprocessor

The single event effects of the sensitivity of a circuit are investigated on a 32-bit microprocessor with a five-stage instruction pipeline by pulsed laser test. The investigation on sensitive mapping of the memory cell is illustrated and then the comparison between the sensitive mapping and the layout of the circuit is made. A comparison result indicates that the area of the sensitive node in sensitive mapping is just the location of the drain in the layout. Therefore, SEE sensitivity in sensitive mapping fits well with that in the physical layout of functional units, which can directly and objectively indicate the size and distribution of sensitive areas. The investigation of sensitive mapping is a meaningful way to verify the hardened effect and provide a reference for improving hardened design by combining with the physical layout.     

铸中华品牌 葆企业长盛

翻开中国近代制笔史,中国第一铅笔股份有限公司的影响是巨大的。直至今天,中铅公司仍在中国制笔界,特别是铅笔行业保持着规模、效益、质量、品种、出口等方面第一的地位,被国际誉为中国铅笔的代名词。一个创立于1935年,已近70年历史的老企业,为什么能在企业运行的各个关键时刻,抓住机遇,开拓前进原因是多方面的,主要是如下三个方面:     

电控单体泵电磁阀动态响应特性数值仿真

为了定量了解电磁阀参数对电碰阀动态响应特性的影响，用ANSYS对应用在电控单体泵上的电磁闯进行有限元建模，模拟了电磁阀在恒电压驱动下的动态响应过程。在计算方法得到实验验证的基础上，研究了驱动电压、初始气隙和弹簧预紧力三个参数对电磁阀整个关闭过程的影响，给出电磁阀在不同参数下线圈电流、阀杆位移和电磁力变化曲线，为电磁阀的参数匹配提供了依据。以此为依据，确定了这三个参数。     

聚合物发光电化学池研究进展

共轭聚合物是一类结合了光学、半导体电子性能和聚合物加工性能的新型材料,1995年聚合物发光电化学池出现以来就引起了广泛关注,文章在对文献结果分析的基础上总结了影响聚合物发光电化学池性能的若干因素和最新的研究进展。