Effect of substituting Mm with La on the electrochemical performances of Co-free LaxMm1−x(NiMnSiAlFe)4.9 (x = 0–1) electrode alloys prepared by casting and rapid quenching

In order to enhance the electrochemical capacity of the Co-free AB₅-type electrode alloy, Mm in the alloys was substituted with La and Co-free La_xMm_1−x(NiMnSiAlFe)_4.9 (x = 0, 0.45, 0.75, 1.0) hydrogen storage alloys were prepared by casting and rapid quenching. The effects of the substituting Mm with La on the electrochemical performances of the as-cast and quenched alloys were investigated in detail. The obtained results show that substituting Mm with La can enhance markedly the capacities of the as-cast and quenched alloys. When the amount of substituting Mm with La, x increased from 0 to 1.0, the maximum capacity of the as-cast alloys at 0.2C rate increased from 273.45 to 304.47 mAh g⁻¹, and the capacity retaining rate (R_h) increased from 59.16 to 59.86%. The capacity of the as-quenched alloys with a quenching rate of 10 m s⁻¹ increased from 236.83 to 300.31 mAh g⁻¹, and the capacity retaining rate (R_h) decreased from 78.69 to 62.29%. The substituting Mm with La had an insignificant effect on the activation capabilities of the as-cast and quenched alloys.     

工程尺度下微震信号及P波初至自动识别AB算法

 为提高工程噪音环境中低信噪比微震信号的自动识别率及其P波自动拾取准确率,结合Allen算法能快速自动拾取震动信号的优点及Bear算法善于拾取低信噪比震动信号P波初至的优势,在Allen算法的基础上,引入Bear算法的加权因子和特征函数,对Allen算法进行改进,提出适用于工程尺度的微震信号及P波初至自动识别的AB(Allen coupled with Bear algorithm)算法。分析AB算法对信号振幅或频率变化的敏感性以及拾取效果,结果表明：(1) AB算法能准确识别微震信号也能同时准确自动拾取信号的P波初至;(2) AB算法的加权因子K、特征函数CF, 值对频率和振幅变化的敏感性高于Allen算法;(3) AB算法对振幅变化比对频率变化敏感;(4) 工程尺度下AB算法微震信号的拾取率高于Allen算法,且P波自动拾取准确率也高于Allen算法。将AB算法用于分析锦屏深部地下实验室实测微震信号：对于弱信号,基于AB算法拾取结果进行微震源定位,定位结果具有更高的可靠性与稳定性;AB算法是一种行之有效,计算简单,适合实时监测微震信号识别及其P波初至拾取。     

Optimization and design of inter-stage amplifier with wide output swing,high speed and high accuracy

To satisfy the design requirements of analog-to-digital converter （ADC） of high speed sampling system in an infrared focal plane array tester with 1024 × 1024 pixels, a first inter-stage amplifier of 12-bit 40- Msample/s pipelined ADC was designed with 0. 35 μm CMOS technology. On the basis of traditional two-stage amplifier, the cross-coupled class AB output stage and cascode compensation were adopted to improve the output vohage swing and bandwidth. Power dissipation was optimized with math tools. Circuit and layout design were completed. Simulation results show that the designed amplifier has good performance of 95 dB dc gain, ±2 V output voltage swing, 190 MHz bandwidth and 63° phase margin with feedback factor 1/4, 33 mW power dissipation and so on, which can meet the system requirements.     

LaNi_(3.15-x)Mn_xCo_(0.25)Al_(0.1)储氢合金结构及电化学性能

为了研究Mn替代Ni对AB3.5型储氢合金结构及电化学性能的影响,采用电弧炉熔炼制备LaNi3.15-xMnxCo0.25Al0.1合金。采用XRD、SEM等材料分析方法以及恒电流充放电等电化学测试技术,研究LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3)合金的结构和电化学储氢性能。结果表明:LaNi3.15-xMnxCo0.25Al0.1(0≤x≤0.3)合金由多相组合形成,合金的主相为LaNi5和La2Ni7;随着Mn替代Ni含量的增加,LaNi5相中a轴和c轴以及晶胞体积增加;合金电极的最大放电容量有所升高,由x=0的238mA·h/g逐渐增加到x=0.3的277.1mA·h/g;高倍率性能随着Mn含量的增加先升高后降低,在x=0.2时合金的高倍率性能最佳。     

Ti对Zr1-xTixMn0.4Cr0.4Ni1.2结构和电化学性能的影响

采用真空电弧炉（在氩气保护下）制备Zr1-xTixMn0.4Cr0.4Ni1.2贮氢合金，通过XRD、SEM和恒流充放电研究了合金的相结构、形貌和电化学性能。结果表明：Ti为C14型Laves相的稳定性元素，随着Ti含量的增加，C14型Laves相增多，C15型Laves相减少。当x=0．1时，合金综合性能最好，表现出良好的活化性能、循环稳定性能和高倍率放电特性，在放电电流300mA／g的条件下，充放电循环50次，合金保持稳定的放电容量。当X〉0．1时，合金放电容量下降。Ti的加入使合金氢化物稳定性降低，加入少量Ti，有利于合金的放电容量的提高和高倍率放电性能的提高。     

三菱PLC、AB变频器恒压供水系统的应用

在水资源十分严峻的形势下,节约用水迫在眉睫。建立节水型社会,进而促进节水型社会的建立已经成为保证水资源可持续利用的必然要求。工厂用水更应如此,数据显示,如果采用循环水系统,即一水多用,则工厂的用水可节约40%~90%左右。本文介绍的变频控制恒压供水系统,既体现了变频控制恒压供水的技术优势,同时也全面介绍了三菱PLC、AB变频调速恒压供水系统的运行模式及运行中的注意事项。     

AB5型储氢合金性能波动的原因探析

通过研究稀土原料中的杂质及合金的微观组织,探讨了用感应炉批量生产ＡＢ５型储氢合金性能波动的可能原因。储氢合金的性能由合金的成分、微观组织和表面状态决定。合金性能波动除受浇铸时的冷却条件影响外,还与稀土原料中铁、镁等杂质及熔炼工艺因素有关。     

常温NTC热敏电阻的几种材料

本文介绍了尖晶石型氧化物的类型和特殊电学性质。并叙述了NTC热敏电阻材料选择和配方要求以及在制备热敏电阻元件时如何选择系列氧化物。     

Influence of transverse Interdot Coupling on electron transport properties in a Double-Ouantum-Dot Aharonov-Bohm Structure

By means of modified rate Equations We inVestigate the influence of the transVerse interdot coupling on theAharonoV-Bohm ( AB) structure, Which is composed of two coupled quantum dots ( GDs) sandWiched betWeen source and drain. The numerical results show that the interdot coupling betWeen the two GDs can cause a temporal oscillation in electronoccupation at the initial stage of the quantum dynamics, While the source-drain current decays monotonically to a stationary Value. On the other hand, the interdot coupling diVides the AB ring into two coupled subrings. That destroys the normal AB oscillation and generates a new and complex periodic oscillation With its period related to the magnetic flux ratio.     

An Unsteady Oscillatory Flow of Generalized Casson Fluid with Heat and Mass Transfer: A Comparative Fractional Model

It is of high interest to study laminar flow with mass and heat transfer phenomena that occur in a viscoelastic fluid taken over a vertical plate due to its importance in many technological processes and its increased industrial applications. Because of its wide range of applications, this study aims at evaluating the solutions corresponding to Casson fluids’ oscillating flow using fractional-derivatives. As it has a combined mass-heat transfer effect, we considered the fluid flow upon an oscillatory infinite vertical-plate. Furthermore, we used two new fractional approaches of fractional derivatives, named AB (Atangana–Baleanu) and CF (Caputo–Fabrizio), on dimensionless governing equations and then we compared their results. The Laplace transformation technique is used to get the most accurate solutions of oscillating motion of any generalized Casson fluid because of the Cosine oscillation passed over the infinite vertical-plate. We obtained and analyzed the distribution of concentration, expressions for the velocity-field and the temperature graphically, using various parameters of interest. We also analyzed the Nusselt number and the skin friction due to their important engineering usage.