3,651 research outputs found

    Improvement of Electrochemical Performance of Manganese-based Lithium-Rich Cathode Materials for Lithium-ion Battery

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    近年来,锂离子电池富锂锰基正极材料xLi2MnO3•(1-x)LiMO2(M=Mn,Co,Cr,Ni等)由于具有较高的比容量(≥250mAh/g)、热稳定性好、成本低廉以及对环境友好等优点,引起了研究者的广泛关注和研究。本论文选择Li1.14Ni0.18Mn0.62O2富锂锰基正极材料作为研究对象,采用一种简单的熔融盐法,以改善电化学性能为目标,对于熔融盐的选择、煅烧温度及时间的控制、熔融盐用量等条件进行研究,调控了材料的结构并提高了电化学性能;然后通过使用新型粘结剂,抑制了该材料的电压衰减,进一步提高了电化学性能。 1.分别采用LiCl、NaCl、KCl作为熔融盐,通过改变温度...Recently, layered manganese-based lithium-rich cathode matierials with a formula of xLi2MnO3•(1-x)LiMO2 (M=Mn, Ni, Co, Cr et al) draw attention of researchers due to the exceptional high capacity, low cost, thermo stablility and environmental friendliness. In this work, Li1.14Ni0.18Mn0.62O2 has been synthesized by a molten salt method. The experiment conditions, such as molten salt, sinterin...学位:工学硕士院系专业:能源学院_能源化工学号:3242013115230

    Financial Analysis of King Long

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    2014年通过股权划拨,福汽集团取代了厦门海翼集团,成为金龙汽车新的控股股东,金龙汽车从市属国有控股企业变为省属国有控股企业。在十八大报告明确要求深化国有企业的改革与发展的政治背景下,基于福汽集团控股下的金龙汽车,一方面要整合内部子公司(厦门金龙、厦门金旅、苏州金龙)的资源,减少之间的内耗和相互竞争,提高经营业绩,以克服大中型客行业增长乏力等企业发展问题;另一方面要落实中国企改革的新模式,推进产权的多元化,以发挥市场化的企业经营效率。 本文主要以财务分析的角度,运用财务三维分析、指标分析及指标的分解分析等工具,对金龙汽车财务分析,以剖析金龙的内部经营情况。给刚控股金龙汽车的福汽集团提供参考,...During the interest allocation in 2014, Fujian Motor Group, replacing Xiamen CCRE Group, became the new controlling shareholder of King Long Bus and thus King Long changed from a municipal state-owned holding enterprise into a provincial state-owned holding enterprise. Under the political background of deepening reform and development of state-owned enterprises as instructed by report at 18th Part...学位:工商管理硕士院系专业:管理学院_工商管理硕士(工商管理硕士)学号:1792012115101

    What Causes Financial Frauds and How to Prevent Them: A Case Study of Yunnan Greenland

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    我国资本市场上频繁出现的财务造假事件,给广大投资者带来了巨大损失,摧毁着上市公司的信誉和投资者的信心,阻碍了我国资本市场的正常发展。为此需要对上市公司财务造假的内部动因、手段、产生环境进行分析,从而找到问题的症结所在,并有针对性的提出建议。 本文首先从理论研究入手,通过对财务造假相关文献回顾,对财务造假动因几种主要理论进行了研究,在此基础上根据博弈理论构建了造假-监督博弈模型,并通过推导分析得出了影响造假概率的几个关键因素(惩罚力度、造假额外收益、造假成本、监管成本)及其相互之间的关系;对财务造假的一些常见手段进行了总结。 其次,介绍了我国上市公司财务造假的一个典型案例——绿大地案,以绿大...Cases involving financial frauds have been reported repeatedly in China’s capital market and caused heavy losses to investors. They have also tarnished the image of listed companies and shaken investors’ confidence, thus hurting the development of the country’s capital market. Thus it is necessary to find out the crux of the problem through analyzing the reasons behind financial frauds by some lis...学位:会计硕士院系专业:管理学院_会计硕士学号:X201015703

    科学处与新中国早期的科学领导工作(1951~1956年)

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    科学处(1951~1966年)是中宣部下设的一个职能机构,它在中共中央党务系统内负责科学领域事务,对新中国早期(1951~1956年)的科学领导工作拥有广泛的影响。科学处的成立是新中国成立后中宣部自身管理领域扩大和调整的产物,目的在于强化党对科学工作的领导。由于其中宣部的背景,科学处实际承担了一部分对科学工作如对科学院的"日常"行政和管理职能,成为党领导科学工作的重要管道。此外,科学处还参与了科学政策事件和知识分子政策事件的处理,在某些知识分子政策事件中扮演了重要的角色,对一些科学工作的走向产生了深远的影响。对科学处的研究有助于我们了解新中国党领导科学、科学与政治之间的关系

    Selective hydrogenolysis of sorbitol on Ni/La202CO3 catalysts

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    采用共沉淀法制各了具有协同稳定作用的Ni/La2O2CO3催化剂,用于山梨醇选择性氢解为小分子醇的研究。采用X射线衍射、氢气程序升温还原、C02程序升温脱附和扫描电镜对催化剂进行了表征。考察了不同配比Ni、La的加氢位点和碱性调控对山梨醇氢解产物的影响。结果表明,Ni、La摩尔比为2:3时,山梨醇转化率达到98.6%,C2~c3多元醇的产率达到43.8%,催化剂经2次反应后对山梨醇的转化率仍高达90%。探究了催化剂从酸性到碱性调变过程中,山梨醇氢解的产物分布,并提出了反应路径

    Automatic mapping aquaculture in coastal zone from TM imagery with OBIA approach

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    IEEE GRSS; The Geographical Society of China<span class="MedBlackText">Aquaculture area monitoring is of great importance for coastal zone sustainable management and planning. This paper focuses on the development and assessment of an automatic approach for aquaculture mapping in coastal zone from TM imagery. The contribution mainly consists of three aspects: first, utilizes the Multi-scale segmentation/object relationship modeling (MSS/ORM) strategy on the object based image analysis (OBIA) of TM imagery; second, evaluates the effectiveness GLCM homogeneity texture feature on pond aquaculture area information extraction; third, compares the analysis results from three different approaches, namely pixelbased maximum likelihood classifier (MLC), One-step supervised OBIA with stand nearest neighbor (SNN) and MSS/ORM OBIA strategy. The final result shows that the MSS/ORM OBIA approach greatly improves the classification accuracy and has good potential for automatic pond aquaculture land mapping in coastal zone from TM imagery.</span

    长江中游三个湖泊中华绒螯蟹生长变化研究

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    选择长江中游的牛山湖、武湖和东汤逊湖三个典型的河蟹养殖湖区作为研究地点,从2009年2月起逐月调查湖泊放流河蟹体重和壳宽的生长变化,并同时记录投喂管理情况和收集试验湖区的水化特征及底栖生物资源状况。调查发现,河蟹在4、5、6月特定生长率最大,此时为河蟹生长的高峰期。在三个湖区间,生长有显著性差异,在收获季节,武湖河蟹的平均壳宽和体重均显著性大于另外两个湖区(P0.05);这种情形可能主要与为湖泊的天然饵料资源的种类和丰度有关

    Laser Fabrication of Hybrid Graphene/Silver SERS Chips and Their Applications

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    石墨烯/银复合结构SERS器件可充分发挥石墨烯与银纳米结构的特性,具有良好的性能。银纳米结构SERS活性强,但稳定性差,在空气中易氧化,限制了银SERS器件的应用。石墨烯具有原子级的厚度,良好的光学透过率,稳定的化学性质,是SERS器件理想的壳层材料,可有效阻止银纳米结构与探针分子及周围环境接触,提高基底稳定性。并且石墨烯本身还具有拉曼信号增强、荧光猝灭、探针分子富集等功能,使石墨烯/银复合结构成为SERS信号检测的理想平台。论文针对石墨烯/银复合结构SERS器件制备方面存在的问题展开研究工作,提出了两种工艺简单的石墨烯/银复合结构SERS器件快速制备方法,并根据SERS器件的特性,研制了便携...Graphene/silver is a promising composite structure for SERS chips with both the excellent performance of graphene and silver nanostructures. Graphene has been envisioned as one of the best shell materials for SERS chips to improve the stability owing to its atomic thickness, excellent optical transmittance and stable chemical property. Moreover, graphene can also function as additional signal enha...学位:工学博士院系专业:航空航天学院_测试计量技术及仪器学号:1992013015422

    Effect of ZnO on Cu/ZnO/Al_2O_3 catalysts for methanol synthesis

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    [中文文摘]用高速碰撞共沉淀法制备m(CuO) /m(ZnO) /m(Al2 O3 )比分别为 60 /3 0 /1 0和 3 0 /60 /1 0的 1 #和 2 #催化剂 ,结果表明高ZnO的 2 #催化剂活性较好 ,分散度较大。XPS测试表明 2 #催化剂表面ZnO吸附的中间体 (CHx 或CHxO)较多且表面的Cu+1浓度较高 ,从而促进CO加氢合成甲醇的活性。[英文文摘]Cu/ZnO/Al_2O_3 catalysts with ratios of 60/30/10 and 30/60/10 have been prepared by high speed collision coprecipitation method. The performance of the catalyst with the higher ZnO content shows the higher activity in methanol synthesis. The characterization results indicated that the catalyst with the higher ZnO content has higher dispersion. On the surface of the higher ZnO content catalyst, there was more Cu+1 and more intermediate (CH_x and CH_xO) adsorpted. It is beneficial for the CO hydrogenating to produce methanol

    Trade Openness and Income Inequality in China

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    从上个世纪七、八十年代以来,随着经济全球化和世界贸易自由化进程的加 快,南北贸易、北北贸易、产业间贸易、产业内贸易等各种形式的国际贸易迅速发 展。伴随着这些贸易形式的发展,各国国内普遍出现了劳动者工资收入差距扩大的 趋势,国际贸易与工资收入差距关系的研究遂成为国际经济学领域理论研究和经验 分析的热点和难点之一。就中国的实际而言,自1978年改革开放以来,对外贸易 在促进中国经济增长的同时获得快速发展,中国因此成为公认的世界贸易大国。但 对外贸易飞速发展同时伴随着收入不平等的扩大,二者从时间进程上看似乎存在一 致性,那么贸易开放是否影响了中国的收入差距?其影响的机制、方向和大小又如...From the seventies and eighties of the last century,as the acceleration of world trade liberalization, international trade ineluding the North-South trade, North-North trade, inter-industry trade, intra-industry trade and other international trade forms has developed rapidly. At the same time of the trade liberalization, the wage income inequality enlarges in all kinds of countries. So the rel...学位:经济学博士院系专业:经济学院国际贸易系_世界经济学号:1572009015341
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