A new cladding technology to bond aluminium on magnesium

ABSTRACT

An in situ hot press bonding technology has been developed to clad aluminium on magnesium. Followed by regular hot rolling, magnesium sheets, covered by ductile and corrosion-resistant aluminium without detectable oxides in the interface, are produced. The new technology requires no welding, vacuum, protective atmosphere or barrier layer, and it makes good interfacial strength and rollability. Aluminium–magnesium intermetallic phases are formed along the clad–core interface at elevated temperatures. They are not detrimental under compression but may cause clad-core delamination in tensile strain. However, the tensile failure is more dependent on the formability of magnesium core than on the strength of interface.     

钻井(进)中的环保问题

讨论了钻井(进)过程中各环节出现的对环境的影响，提出了相应的对策。虽然各环节对环境的影响看起来不大，但总量和长时间对环境的破坏作用将会很大，希望能引起大家行动起来保护环境。     

人的全面发展与社会主义市场经济

分析人的全面发展与社会主义市场经济的关系,以及在社会主义市场经济条件下,如何实现人的发展.     

刮板输送机的启动动力特性与软启动技术

通过对刮板输送机的启动动力特性分析 ,找出了刮板输送机在启动过程中存在的问题。对几种现有的软启动装置进行分析、比较、研究 ,得出了对刮板输送机启动的合理性要求     

声发射测量原岩应力研究现状及进展

综述了声发射测量原岩应力的国内外研究现状和目前所存在的主要问题，结合信号处理小波分析方法的研究成果，说明了将小波分析引入到原岩应力测量的重要性，最后提出了基于小波分析的综合研究方法作为声发射测量原岩应力的进一步研究方向。     

选矿工艺设备配置图智能CAD系统的研究

对近年来选矿厂ＣＡＤ的研究工作进行了评述，探讨了智能ＣＡＤ技术在选矿工艺设备配置设计中的应用。     

Is activity-based working impacting health,work performance and perceptions? A systematic review

ABSTRACT

Numerous claims have been made about the benefits of activity-based working (ABW) on workers’ health and work performance. Yet, it is unclear if these claims are proven. This systematic review aims to establish whether there is an evidence base for the effects of ABW on health, work performance and perceptions of the work environment. Eight databases were searched in September 2016. Three reviewers independently screened titles and abstracts and assessed the studies and extracted the data. Seventeen studies involving 36,039 participants were included. The study designs varied in rigorousness from qualitative studies to pre–post-trials and in sample size ranging from 12 to 11,799. This review found that ABW has positive merits in the areas of interaction, communication, control of time and space, and satisfaction with the workspace; however, it is unfavourable for concentration and privacy. For physical and mental health, the evidence is equivocal. ABW seems to be a promising concept that can be implemented and promoted based on some benefits for work performance and perceptions of the work environment when it is coupled with appropriate management support and organization. More high-quality research is needed to strengthen the evidence base further and establish its health effects.     

水溶性聚丙烯酸类高效减水剂的合成及表征

以丙烯酸、丙烯酸甲酯、甲基丙烯酸、顺丁烯二酸酐、烯丙基磺酸钠单体为原料,自由基共聚合成了不同单体组合和配比、不同分子量的不同结构类型的丙烯酸类系列减水剂。通过红外光谱法对共聚物的组成进行了表征,分别采用黏度法和电泳法等方法测试了系列聚合物的特性黏数、减水剂水溶液的表面张力、掺减水剂水泥浆体的ζ电位和掺减水剂的水泥净浆流动度。结果显示,系列丙烯酸类聚合物均具有一定的表面活性,能使水泥浆体ζ电位的绝对值增大;减水剂的链结构、分子量、羧酸根负离子的数量及其分布及基团的空间位阻大小等都对减水性能产生影响。