Suppression of the α → β-nickel hydroxide transformation in concentrated alkali: Role of dissolved cations

The presence of dissolved cations such as Al and Zn in alkaline electrolyte (6 M KOH) suppresses the -nickel hydroxide transformation. The uptake of Al (10 mol%) and Zn (30 mol%) exhibited by the active material likely stabilizes the -phase. Dissolved Al is deleterious to the performance of the nickel hydroxide electrode, whereas, dissolved Zn enhances the specific discharge capacity of nickel hydroxide by approximately 25% showing that the mode of metal uptake is different in the two cases.     

A novel shaft-less double suction mini pump

A novel double suction shaft-less mini pump was developed for heat control of small energy systems in this study.The mini pump impeller with an exit diameter of 40 mm was combined with the motor rotor supported by the hybrid dynamic bearing.The specific speed of the pump was 125 min-1 m3 min-1 m.The hydraulic performance of the pump was investigated experimen-tally under four rotational speeds.From the test results,it was recognized that the pump could provide a flow discharge of 5 L/min and head of 1.5 m,w...     

Strength of limestone-based non-calcined cement and its properties

A new type of cement was prepared with ground limestone powder, blastfurnace slag, steel slag and gypsum without calcination. The fraction of ground limestone powder in the cement was as high as 40 wt%–60 wt% without Portland clinker. All of its physical properties can meet the requirements of masonry cement standards. The impact of limestone content on physical properties of the cement and determined its impact on law was investigated. The steel slag can excit the aquation activity of this cement effectively, and the influence of its quantity on the strength of the materials was studied, which shows that the optimum quantity of mixing is 10%. By way of changing the different content of the lime stone by quartzy sample, the law of the compression strength and the PH value was determined, confirming that the lime stone can promote the early aquation of the slag and improve the early strength. The main hydration product of this cement is calcium aluminate hydrate, ettringite and calcium silicate hydrate, as indicated by XRD and SEM analysis.     

基于红外原理的微型多气体检测系统的设计

为了解决目前煤矿瓦斯事故以及大量使用天然气的家庭安全、环境污染等问题,设计并开发了一种具有集成化、微型化的红外多气体检测系统,通过实验数据的测试对比和数据分析,这种系统达到了微功耗、微体积、宽量程、高分辨率等技术要求,且能集成多气体检测的微型检测系统.重点介绍了红外检测的光学原理,以及从单气体检测引入到集成多气体检测的设计思想和方法,并介绍了有关CAN总线的数据传输方式和无线数据通信方式在系统中的应用.     

Mechanical performance and texture characteristic of an IF steel containing Nb and Ti by double cold rolling

Single cold rolling and double cold rolling were applied to hot rolled strips with different reduction ratios. The evolutions of {100},{111} and Goss face texture during double rolling were investigated by comparing the orientation distribution function(ODF) of the double rolled sample with that of the single rolled one. The double cold rolling texture is characterized by a higher γ-texture and a lower α-texture,and the {111}<112> component is improved remarkably. Based on the TEM observation and mechanical...     

Preparation and electrochemical characterization of activated carbons by chemical-physical activation

A process was proposed based on the combination of chemical and physical activation for the production of activated carbons used as the electrode material for electric double layer capacitor (EDLC). By material characterization and electrochemical methods, the influences of the activitation process on the specific surface area, pore structure and electrochemical properties of the activated carbons were investigated. The results show that specific surface area, the mesopore volume, and the specific capacitance increase with the increase of the mass ratio of KOH to char (m(KOH)/m(char)) and the activation time, respectively. When m(KOH)/m(char) is 4.0, the specific surface area and the mesopore volume reach the maximum values, i.e. 1 960 m²/g and 0.308 4 cm³/g, and the specific capacitance is 120.7 F/g synchronously. Compared with the chemical activation, the activated carbons prepared by chemical-physical activation show a larger mesopore volume, a higher ratio of mesopore and a larger specific capacitance. Foundation item: Project(2007BAE12B01) supported by the National Key Technology Research and Development Program of China     

Influence of nitrogen hetero-substitution on the electrochemical performance of coal-based activated carbons measured in non-aqueous electrolyte

Nitrogen-containing carbons were prepared by modification of activated carbons. The modified carbons were used as electrode materials with improved electrochemical performance. Precursor anthracite was activated by KOH (KOH: anthracite= 1:1), modified by melamine or urea and then treated at 1173 K to obtain the modified carbons. The porous structure, the chemical composition and the electrochemical characteristics of the carbons were investigated by nitrogen sorption, XPS and electrochemical methods respectively. Electrochemical experiments were performed in an organic electrolytic solution of 1 M (C2H5)4NBF4/PC.The samples modified by the different methods showed differences in chemical composition that introduced varying degrees of electrochemical performance enhancement. The presence of nitrogen enhanced the electron donor properties and the surface wettability of the activated carbons: this ensured a sufficient utilization of the exposed surface for charge storage.     

基于CSY型传感器的悬臂力学试验确定材料弹性模量的方法

对在CSY型传感器综合实验仪上拓展悬臂梁力学实验进行了研究,研究了在该实验仪上实现材料弹性模量的测定.通过材料力学的理论推导出悬臂梁弹性模量与其受力和挠度比值的关系,通过应变式传感器的实验确定出悬臂梁受力与其挠度的比值关系,进一步可推导出悬臂梁材料的弹性模量,并验证了该方法的可行性及有效性.该方法集合了电阻应变效应、全桥差动电路等传感器电测技术以及材料弹性力学、悬臂梁结构力学的基础知识,具有综合应用性.同时,对高校实验室如何有效利用设备资源、开发拓展型实验有一定的示范作用.     

矿渣掺量对水泥性能的影响

采用矿渣与熟料分别粉磨再混合的方式,研究了不同掺量和不同细度的矿渣对水泥强度和凝结时间的影响,确定了水泥中矿渣的最佳掺量.     

基于T-S模型的二级倒立摆模糊控制研究

对非线性、强耦合和绝对不稳定的二级倒立摆进行了运动分析,并针对实验用的二级倒立摆,建立了其运动的状态方程.根据实验中运动的特点,提出了基于T-S模型的模糊控制,取得了较好的控制效果.