纳米氧化锌制备过程成核与生长控制

均相沉淀法制备纳米氧化锌的关键是成核与生长控制。过饱和度越大 ,成核数量越多 ,则生成的晶粒越小。成核数量与反应物浓度即Zn2 + 和OH-的浓度有关。采用尿素为沉淀剂 ,添加有机物羧甲基纤维素作分散剂以控制微小晶粒间的叠合生长 ,在温度 (130℃ )和反应时间 (2h～ 5h)下热压处理 ,制备了粒径较小、粒度分布均匀的纳米氧化锌     

武山铜矿北副井延深工程施工实践

本文简述了武山铜矿北副井延深工程的施工方案、施工技术与管理、施工后的效果及其施工经验总结     

电动机冷却风机变频系统的改造和效果

本文简述了我厂主电机冷却风机变频系统 ,以及交流异步电动机的变频调速原理 ,介绍了变频器的工作原理、特点 ,说明了新旧控制系统的优缺点和节能效果。     

浅析低压铸造的工艺特点

根据低压铸造的工艺流程、工作原理等特性 ,综合分析了低压铸造的工艺特点 ,对低压铸造的生产具有很高的借鉴作用     

Grain-boundary diffusion and precipitate trapping of hydrogen in ultrafine-grained austenitic stainless steels processed by high-pressure torsion

This study was conducted to clarify the effects of grain boundaries and precipitates on room-temperature hydrogen transport in two types of austenitic stainless steels with ultrafine-grained structures produced by high-pressure torsion (HPT) and subsequent annealing. The grains in the Fe-25Ni-15Cr (in mass%) alloy containing Ti and the Fe-25Cr-20Ni alloy were refined by the HPT-processing to ∼150 and ∼85 nm, respectively. The high-temperature annealing after the HPT processing led to the precipitation of η-Ni₃Ti for the former and σ-FeCr for the latter. In the HPT-processed specimens, hydrogen diffusivity was enhanced through short-circuit diffusion because of the increased population of grain boundaries in comparison with the increased opportunity of hydrogen trapping on dislocations. As for the post-HPT-annealed specimens having the precipitates, the hydrogen diffusion was hindered by the hydrogen trapping on η-Ni₃Ti precipitates, but was not affected by σ-FeCr precipitation. This depends on the affinity between hydrogen and constituting elements.     

Functional cooperation of cyclin C and c-Myc in mediating homotypic cell adhesion via very late antigen-4 activation and vascular cell adhesion molecule-1 induction

Very late antigen-4 (VLA-4)/vascular cell adhesion molecule-1 (VCAM-1) are a pair of adhesion molecules mediating cell-cell interaction. The binding activity of each depends on its surface expression, yet integrin activity can also be modulated through inside-out signaling. However, the specific intracellular molecules involved in modulating integrin VLA-4 activation via inside-out signaling or in regulating VCAM-1 expression are poorly understood. We show here that constitutive coexpression of cyclin C and c-Myc in hematopoietic BAF-B03 cells induces homotypic cell adhesion, which results from enhanced VLA-4 ligand-binding activity and induced expression of VCAM-1. Furthermore, regulation of cell adhesion appears to be a feature unique to cyclin C, but not other G1 cyclins, E and D3, and its regulatory function is independent of CDK8 kinase activity. Our results provide a novel role for cyclin C and c-Myc in the regulation of cell adhesion through distinct mechanisms.     

激光在金属壳雷管编码中的应用

提出激光在金属壳雷管外表进行13位阿拉伯数字编码,应用计算机软件、硬件、激光、精密机械、自动控制于一体,生产效率高,稳定可靠,无污染.     

东乡铜矿的环保综合治理

介绍东乡铜矿井下水的治理和综合利用、井下废石的处理以及选矿尾砂的综合应用 ,井下高温毒气的治理、尾矿坝的复土植被并继续为生产服务等环保综合治理情况。     

水相析晶点对乳化炸药稳定性的影响

文章采用对乳化炸药水相析晶点的测定方法，研究了制备乳化炸药的几种水相析晶点对其稳定性的影响t最后得出了相应的结论。结果表明乳化炸药水相析晶点越低，乳化炸药越稳定，基质水溶值也越小；经16次高低温循环，乳化炸药的殉爆距离仍达到20mm。     

提高选铜回收率的流程改造

在矿石性质和粒级分析的基础上 ,利用现有设施 ,进行流程改造 ,提高选铜回收率 ,为企业资源利用提供有利的依据