球磨制备Mg-In-Zn三元固溶体的储氢性能及机理     

钟海长  赖桂文  朱子文  郑青榕 《鹭江职业大学学报》2014,(3):17-21

采用“烧结-球磨”方法制备Mg0．92 In0．05 Zn0．03三元固溶体合金,减小了Mg的晶格常数.利用粉末X-射线衍射分析合金的相组成、微观结构和吸放氢过程的相转变,通过扫描电镜观察合金的微观形貌及相分布.采用体积法测定合金的等温吸放氢曲线（ PCT）和动力学曲线,确定了合金的吸放氢反应焓变、熵变及氢化反应激活能.结果表明： Mg0．92 In0．05 Zn0．03三元固溶体具有良好的活化性能和动力学性能,脱氢反应焓降低至-68．6 kJ/mol H2.  相似文献   

企业知识管理技术     

张艳 《情报探索》2014,(3):99-100,102

从知识采集与存储技术、知识开发技术、知识共享技术、知识安全技术等4个方面,简述了企业知识管理的技术体系.  相似文献   

基于PLC的自动货架设计与实现     

刁鑫  林忠维  杨碧云 《中国科技纵横》2014,(20):70-70

本文介绍了基于PLC（programmable logic controler可编程逻辑控制器）和组态王软件的自动货架的设计方案。下位机主要由西门子S7-200 PLC及相关的电路元件完成现场信息的采集、处理以及控制,上位机采用组态王软件实现监视和选择功能。上、下位机之间通过串口实现通讯。实验结果表明：系统已达到了预期的设计效果。  相似文献   

天线掉漆原因分析及解决措施     

席蕙 《大众科技》2014,(1):74-75,83

针对某产品在高低温贮存过程中出现个别发射天线大面积掉漆现象,通过比较不同工艺方法制备的样件,在温度储存、温度循环试验、漆膜附着力测试情况下是否满足要求,从而查找出该发射天线大面积掉漆的原因。  相似文献   

新型环保节能矿焦槽系统     

马铭 《中国科技纵横》2014,(4):12-13,16

在炼铁生产中,矿焦槽系统产生了大量粉尘,对环境及工人健康造成严重危害,为此我们在矿焦槽系统设计中,通过改进除尘点的密封性、采用环保卸料车等措施,降低了矿焦槽系统除尘风量和除尘设备运行成本,减少了环境污染;同时采用较低温度的烧结环冷热气烘干焦炭技术,降低了焦炭含水量,有利于高炉的顺行及降低生产成本。  相似文献   

从硫碳氮三元共渗看影响零件表面磨损寿命的几个实际问题     

孙超 《中国科技纵横》2014,(13):247-248

近些年来,利用表面热处理提高材料耐磨性的问题一直受到人们的关注。本人也为此进行了辉光离子硫碳氮三元共渗的研究,并从减摩性分析入手取得了较好的研究结果。本文主要从处理后零件表面形成的储油结构、固体润滑剂的形成、硬度梯度对磨损的影响三方面入手进行了表面热处理方面研究。  相似文献   

云计算模式下数据安全存储策略研究     

王瑞娜 《安徽职业技术学院学报》2013,(4):9-12

云计算是目前信息技术发展的热门技术之一,基于云环境的数据存储服务也发展迅速,使越来越多的企业和个人享受到了云存储带来的高效、便捷、低成本的服务,但同时云存储的安全问题也备受用户的关注,文章首先阐述了云存储的基础知识和系统架构;其次,分析了云存储的发展现状;最后针对云存储的安全给出了一些防范策略。  相似文献   

The effect of storage time and freeze-thaw cycles on the stability of serum samples     

Serap Cuhadar  Mehmet Koseoglu  Aysenur Atay  Ahmet Dirican 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(1):70-77

Introduction:

Optimal storage of serum specimens in central laboratories for a long period for multicenter reference interval studies, or epidemiologic studies remains to be determined. We aimed to examine the analytical stability of chemistry analytes following numerous freeze-thaw and long term storage.

Materials and methods:

Serum samples were obtained from 15 patients. Following baseline measurement, sera of each subject were aliquoted and stored at −20 °C for two experiments. A group of sera were kept frozen for up to 1, 2 and 3 months and then analyzed for stability. The other experiment consisted of one to ten times of freeze and thaw cycles. Total of 17 chemistry analytes were assayed at each time point. The results were compared with those obtained from the initial analysis of fresh samples. Median or mean changes from baseline (T₀) concentrations were evaluated both statistically and clinically according to the desirable bias.

Results:

Of the analytes studied, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), gamma-glutamyl transferase (GGT), direct bilirubin, glucose, creatinine, cholesterol, triglycerides, high density lipoprotein (HDL) were stable in all conditions. Blood urea nitrogen (BUN), uric acid, total protein, albumin, total bilirubin, calcium, lactate dehydrogenase (LD) were changed significantly (P < 0.005).

Conclusions:

As a result, common clinical chemistry analytes, with considering the variability of unstable analytes, showed adequote stability after 3 months of storage in sera at −20 °C, or up to ten times of freeze-thaw cycle. All the same, such analysis can only be performed for exceptional cases, and this should be taken into account while planning studies.  相似文献   

Effects of surface modification by Ni, Ti and B on electrochemical properties of Mg1.8Cu0.2Ni hydrogen storage alloy     

JIAO Xiao-yan  WANG Chang-qing  ZHAO N  ZHU Gui-qin 《重庆大学学报(英文版)》2012,11(4):177-182

Amorphous alloy Mg1.8Cu0.2Ni was successfully prepared by mechanical alloying (MA) and a series of (n?x)Nix(Ti?B) composites were synthesized by MA. The electrochemical properties of Mg1.8Cu0.2Ni coated by Ni, Ti and B were studied by cyclic charge-discharge, linear polarization curve, and hydrogen diffusion coefficient experiments. Experimental results indicate that Mg1.8Cu0.2Ni-[0.9Ni0.6(Ti?B)] composite which was MA 30 h exhibited the best performance and its initial discharge capacity arrived to 714.1 mAh/g. After 30 cycles the discharge capacity was above 530 mAh/g, which was much higher than that of Mg1.8Cu0.2Ni. And after 100 cycles it holded still 442.1 mAh/g. On all accounts, after modification by Ni, Ti and B, the initial discharge capacity and high-rate discharge ability of the electrode were evidently increased. At the same time, the cycle performance was also improved significantly.  相似文献   

对最近最久未使用(LRU)置换算法的分析与研究     

褚洪波 《鸡西大学学报》2012,(10):69+81

虚拟存储管理技术的使用大大提高了计算机系统的性能,请求分页存储管理是常用的一种实现虚拟存储的方式,而其中的页面置换算法是其重要的组成部分,算法的好坏直接影响着系统的性能。  相似文献