共查询到20条相似文献，搜索用时 156 毫秒
1.
以开发固体氧化物燃料电池（SOFC）新型阴极材料为目的,采用高温固相反应法合成了一系列钙钛矿型复合氧化物La0.8Sr0．2Mn1-yCOyO3-δ（LSMC,Y分别取0.3,0．5和0．7）,并对Mn位掺杂不同量过渡族元素Co后样品的高温电导率和热膨胀系数进行了研究,发现随着Co含量的增加,材料的电导率和热膨胀系数均增大,其中La0.8Sr0．2Mn0.3Co0.7O3-δ的电导率最高,700℃时,达270．89S·cm^-1。 相似文献
2.
丁芳 《湖南大众传媒职业技术学院学报》2008,8(5)
Web2．0作为2005年以来互联网的一个新应用,掀起了网络媒体变革的开端。相比webl．0,它最主要的贡献是将受众从信息的接收者变成了信息的提供者,它所具有的“众包”以及“社交网络”特征,使受众真正成为网络媒体的主体。 相似文献
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黄元乔 《湖北第二师范学院学报》2009,26(2):4-6
采取三种方法合成了镍钴酸锂电极材料LiaNi0．7Co0.3O2用电化学实验方法研究了合成方法对材料的电化学性能的影响,材料用XRD表征。结果表明：通过预处理后合成的电极材料具有较好的电化学性能,首次充放电比容量可达到196．5和167．9mAh·g^-1。 相似文献
5.
采用固相法和溶胶凝胶法（sol-gel）成功地制备出了LiFePO4．并利用X射线衍射、扫描电镜以及电化学测试等手段，系统地研究了合成条件和方法对材料的结构和电化学性能的影响．研究表明，使用sol—gel方法和固相法，制备出单一相的LiFePO4，其比容量分别为130mAh／g和80mAh／g．采用sol—gel方法制备的LiFePO4作为电池正极材料具有高的比容量和优良的电化学性能． 相似文献
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Web2．0的社会性软件让更多的人投入到互联网，他们贡献内容．参与互联网的建设与完善．从而带来了整个互联网的活跃。通过Web2．0可以接触和了解他人的思想，智慧的互联由此成为可能，而在恰当利用RSS、百科全书（Wiki）、网摘、社会网络（SNS）、P2P、即时信息（IM）等技术进行学习、生活、工作时，呈现在我们面前的将是一个思想灵动、智慧闪烁、无比鲜活的互联网，人们写博客的思想灵动也许就更多。[第一段] 相似文献
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基于Web2．0构建开放式教育资源库 总被引：1，自引：0，他引：1
在Web2．0不断深入发展的背景下,论文分析了教育资源库2．0的特征,提出了基于Web2．0的上海教育资源库软件平台具体建设技术目标,初析了可持续发展的教育资源库的运营模式。最后介绍了利用AJAX、RIA、RSS等技术实现的典型教育资源管理和应用系统案例。 相似文献
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周愉晴 《河北广播电视大学学报》2009,14(6):10-13
由于Web1．0技术的局限,使基于Web1．0的网络课程存在着诸多不足,诸如缺乏科学有效的人际交互的设计,指导、监控学习过程的学习活动设计较少,学习评价与反馈设计简单化等。随着Web2．0在教育领域的推广应用,其在网络课程建设中的优势越来越被学者们认同,Web2．0的理念、技术和应用为网络课程的教学设计带来了更多的可能性,为网络课程的更新换代提供了技术支持。 相似文献
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以磷酸三甲酯（TMP）为阻燃添加剂制备了4种锂离子电池电解液1mol·L^-1LiPF6（1-y％）（ECn-DMC1.0-EMC1.0）-y％TMP（（n,y）=（1,44％）,（1．5,39％）,（2,35％）,（1．0,0％））。考察了碳酸亚乙烯酯——碳酸锂添加剂对采用磷酸三甲酯阻燃添加剂的电解液的石墨负极与LiCoO2正极电化学性能的影响。结果表明,制备的1mol·L^-1 LiPF6 61％（EC1.5-DMC1．0-EMC10）-39％TMP-4％VC-0．05mol·L^-1 Li2CO3电解液具有较好的综合电化学性能,VCLi2CO3添加剂有效抑制了TMP在碳电极的分解和共嵌入行为。采用这种电解液制备的Li／graphite电池的首次放电比容量为336．5mAh·g^-1、以0．1C倍率循环20次的放电比容量为334．5mAh·g^-1,制备的Li／LiCoO2电池的首次放电比容量为145．2mAh·g^-1、以0．1C倍率循环20次的放电比容量为136．5mAh·g^-1。 相似文献
10.
本文在介绍Web2．0的概念、技术、特征及与Web1．0区别的基础上,分析了Web2．0技术的网络教学功能．并给出了基于Web2．0的网络教学案例。 相似文献
11.
作为镍氢电池负极活性物质,储氢合金是影响电极电化学性能的主要因素,对储氢合金进行表面处理可有效提高镍氢电池电极的电化学性能。实验采用电化学方法对储氢合金表面进行镍磷合金修饰处理,通过扫描电镜(SEM)及EDX能谱对电极表面进行了表征分析,测定了处理前后镍氢电池在1.5C和2C下的大电流放电性能,通过交流阻抗和循环伏安曲线对处理后电极进行了评价。测试结果表明,通过电化学修饰镍磷合金,储氢合金电极的大电流放电性能有所提高,电化学阻抗减小,循环寿命增长,有效提高了镍氢电池的性能。 相似文献
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Phosphorus in energy storage has received widespread attention in recent years. Both the high specific capacity and ion mobility of phosphorus may lead to a breakthrough in energy storage materials. Black phosphorus, an allotrope of phosphorus, has a sheet-like structure similar to graphite. In this review, we describe the structure and properties of black phosphorus and characteristics of the conductive electrode material, including theoretical calculation and analysis. The research progress in various ion batteries, including lithium-sulfur batteries, lithium–air batteries, and supercapacitors, is summarized according to the introduction of black phosphorus materials in different electrochemical applications. Among them, with the introduction of black phosphorus in lithium-ion batteries and sodium-ion batteries, the research on the properties of black phosphorus and carbon composite is introduced. Based on the summary, the future development trend and potential of black phosphorus materials in the field of electrochemistry are analyzed. 相似文献
13.
Facile Fabrication of Fe_3O_4@TiO_2@C Yolk–Shell Spheres as Anode Material for Lithium Ion Batteries
Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe_3O_4@TiO_2@C yolk-shell(Y-S) spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe_3O_4@TiO_2@C Y-S spheres possess a good crystallinity.But the diffraction peaks' intensity of Fe_3O_4 crystals in the composites is much weaker than that of bare Fe_3O_4 spheres,indicating that the outer anatase TiO_2@C layer can cover up the diffraction peaks of inner Fe_3O_4 spheres.The yolk-shell structure of Fe_3O_4@TiO_2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe_3O_4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe_3O_4@TiO_2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe_3O_4 spheres and TiO_2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe_3O_4 spheres. 相似文献
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《Early education and development》2013,24(3):265-277
Recent enactment of public laws have mandated early identification of children at risk for delayed development. Several complex assessment batteries have demonstrated satisfactory predictive and classificatory accuracy when biomedical and social-environmental measures obtained in infancy are used as predictors of later IQ scores. Yet, these complex batteries are too costly for wide- spread adoption. The present study examined the effectiveness of smaller sets of predictor variables for correctly identifying children as developmentally delayed at four through seven years of age. The results show that a combination of six biomedical risk items, maternal education level, and four subscale scores from the HOME scale are effective when used as a screening battery across a four year period. The practical implications are for this battery to be used to screen children in the preschool period for developmental delay in the early primary grades. 相似文献
15.
Recent enactment of public laws have mandated early identification of children at risk for delayed development. Several complex assessment batteries have demonstrated satisfactory predictive and classificatory accuracy when biomedical and social-environmental measures obtained in infancy are used as predictors of later IQ scores. Yet, these complex batteries are too costly for wide- spread adoption. The present study examined the effectiveness of smaller sets of predictor variables for correctly identifying children as developmentally delayed at four through seven years of age. The results show that a combination of six biomedical risk items, maternal education level, and four subscale scores from the HOME scale are effective when used as a screening battery across a four year period. The practical implications are for this battery to be used to screen children in the preschool period for developmental delay in the early primary grades. 相似文献
16.
锌锰电池缓蚀剂的研究与进展 总被引：2，自引：0，他引：2
锌锰电池中汞作为缓蚀剂对锌电极有重大影响，无汞电池需要高效代汞缓蚀剂。本文综述了锌锰电池中的锌缓蚀剂的研究与发展，介绍了当前无机、有机缓蚀剂的应用。 相似文献
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提出一种基于双蓄电池储能系统的电压分层协调控制策略,以储能系统为主体协调控制母线电压稳定。根据母线电压的变化范围将系统的动态调节过程划分为稳态阶段与暂态阶段。稳态阶段下,采用双蓄电池组共同协调工作方式,解决了负载突变导致单组蓄电池充放电电流过大,易引起过流故障的问题;暂态阶段下,采用基于改进下垂控制的双蓄电池组轮换协调工作方式,解决了单组蓄电池荷电状态(State of Charge,SOC)达到上、下限后,出现过充或过放情况引起的蓄电池损坏问题。利用Matlab/Simulink平台分别对系统的两种动态调节过程进行仿真,验证各阶段下所提出的工作方式的有效性,并通过单、双蓄电池组的对比,验证所提出控制策略的合理性与优越性。 相似文献
18.
机械载荷对车用动力电池的安全性具有重要影响,其中挤压变形是导致电池短路失效的重要因素之一。锂离子电池在使用中可能会受到外部冲击,从而破坏电池内部结构,导致电池无法正常工作。以方形锂电池为例,研究其在受到压痕作用时的力学特性,通过有限元建模,仿真分析了压痕在不同位置、不同加载速率和不同压头半径下的电池受力情况。结果表明,在高速率、大半径、中心位置的球形压头加载情况下,电池会承受较大压力,压痕区域内不同位置的承受力也不均匀,压痕区域中间位置受力最大,而在电池边缘部分,电池基本上不受力,近乎为零。这为初步判断电池的短路位置和易破坏区域提供了有效参考,也为锂电池设计提供了一定理论依据。 相似文献
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利用细胞微核和核异常监测技术，探讨南孚与三圈5号废电池浸出液对金鱼红细胞微核和核异常的诱发作用．实验结果表明。两种电池浸出液对金鱼的染毒都具有一定的剂量效应和时间效应．T检验结果比较显示，三圈废电池处理液对金鱼红细胞微核和核异常的诱发作用比南孚处理液强；南孚废电池浸出液pH值高于三圈废电池，在短时期内，高浓度的南孚废电池比三圈废电池处理液，对金鱼直接危害的效应更强． 相似文献
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Liliane Rioux 《Environmental Education Research》2011,17(3):353-373
This research is based on Kollmuss and Agyeman’s mode, and aims to determine if the prerequisites for pro‐environmental behaviour, such as the collection of used batteries at school, are ethical, cognitive and environmental. A questionnaire/opinionnaire was given to 102, 14–17‐year‐olds to gather data on: (1) their current recycling habits, (2) their environmental values, (3) their level of knowledge about the harmful effect of used batteries on the environment, (4) their attitude towards collecting used batteries, (5) their attachment to the neighbourhood, (6) their perceived behavioural control and finally (7) their intention to act. The number of used batteries brought by each school child was recorded over a four‐month period. Results show that young people’s behaviour of collecting used batteries can be predicted by ethical (pro‐environmental values), affective (neighbourhood attachment) and cognitive (perceived behavioural control) variables (R 2 = .38; p > .01). 相似文献