铜氧化物的晶体结构参量与超导电性

以ｄＡ（ＣｕＯ２面上Ｃｕ（Ｐ）和项角氧Ｏ（Ａ）键长）对Ｖｄ［沿Ｃｕ（Ｐ）－Ｏ（Ａ）键和沿Ｃｕ（Ｐ）－Ｏ（Ｐ）键方向一个空穴的平均Ｍａｄｅｌｕｎｇ位势差］做图，发现所有铜氧化物超导体的转变温度和结构参量存在一确定的变化规律，不同超导系统被明显地分离开来，Ｔｃ既随ｄＡ也随Ｖｄ的增大而增大．本文从晶体结构的角度分析了产生该现象的原因．     

负离子原子探针中负离子的飞行轨迹

本基于双曲面形样品针尖,计算了负离子原子探针中负离子的飞行轨迹,结果表明,虽然负离子的飞行轨迹与样品针尖形状、针尖到荧光屏的距离、正偏压、负脉冲、负离子的质荷比等因素有关,但除样品针尖附近外,在外针尖到荧光屏的整个区域内,负离子的飞行轨迹近似为线性,并且比同一系统正场蒸发时正离子的飞行迹略向荧光屏边缘偏离。     

从中国式英语看母语文化的负迁移

中国式英语现象是个十分复杂的课题,而由中西文化方面的差异所引起的中国式英语现象更是对英语学习者有害。因此,本文将从母语文化的负迁移的具体方面入手,分析种种文化负迁移所致的中国式英语的表现。     

试论白语的否定词和否定表达形式

作为一种重要的语法意义范畴，白语的否定词及其表达形式体现了白语语言结构的复杂性和独特的发展面貌：方言间否定词的意义和用法有较大差别，否定词构词方法经历了从屈折到分析的重大变化，不同来源的否定词并存并用，并逐渐形成优势型否定词及其表达方式。     

不对称运行中的负序电流

具体分析了产生负序电流的多种情况,并结合实例全面及深入地阐述负序电流对发电机及电力系统的危害,进一步探讨了发电机对负序电流的承受能力、负序电流的定量分析及采取的相应措施。     

关于一类子集格的刻划

讨论了A：{1,2,3…n}集合上子集格的D-类的一些性质,并刻划了子集格上的Munn半群。     

高校教师胜任力提升视角下负激励强化管理

人才资源是第一资源,高校教师资源作为高校中最重要的资源,其胜任力的整体情况对于高校的生存和发展具有重大的影响.从负激励强化的角度来评价和强化高校教师胜任力,为研究高校教师胜任力提升提供了一个全新的视角.     

英语写作中母语负迁移影响分析

本文从母语负迁移的角度对英语写作进行初步探讨。分析了由于汉语干扰因素的影响而使学生不能正确表达词义的原因,并针对这些错误,提出了避免错误的对策,以便提高学生的英语写作水平及写作教学效果。     

Quantum magnetic excitations from stripes in copper oxide superconductors

In the copper oxide parent compounds of the high-transition-temperature superconductors the valence electrons are localized--one per copper site--by strong intra-atomic Coulomb repulsion. A symptom of this localization is antiferromagnetism, where the spins of localized electrons alternate between up and down. Superconductivity appears when mobile 'holes' are doped into this insulating state, and it coexists with antiferromagnetic fluctuations. In one approach to describing the coexistence, the holes are believed to self-organize into 'stripes' that alternate with antiferromagnetic (insulating) regions within copper oxide planes, which would necessitate an unconventional mechanism of superconductivity. There is an apparent problem with this picture, however: measurements of magnetic excitations in superconducting YBa2Cu3O6+x near optimum doping are incompatible with the naive expectations for a material with stripes. Here we report neutron scattering measurements on stripe-ordered La1.875Ba0.125CuO4. We show that the measured excitations are, surprisingly, quite similar to those in YBa2Cu3O6+x (refs 9, 10) (that is, the predicted spectrum of magnetic excitations is wrong). We find instead that the observed spectrum can be understood within a stripe model by taking account of quantum excitations. Our results support the concept that stripe correlations are essential to high-transition-temperature superconductivity.     

英语数字夸张的作用及翻译

数字夸张是夸张手法的一种,在文学作品及日常会话中随处可见。本文试通过具体实例探讨一下英语数字夸张的作用及翻译处理。     

从写作中的词汇搭配错误看母语的负迁移

本文通过分析中国大学生英语习作中的词汇搭配错误情况,探讨了有关母语在英语学习中的干扰作用,认为源于母语干扰的词汇搭配错误主要有五种类型。     

BCS-BEC过渡区原子费米气体的动态性研究

研究BCS-BEC过渡区原子费米气体依赖时间的Ginzburg-Landau方程的平面波解及其动态性。主要研究该方程各个系数a、b、c、d 之间的关系,以及原子费米气体的化学势？和能量阀值2v ,温度T 和极化率h之间的关系。     

1990-2010年长三角城市群城市扩展时空规律分析?

随着城市化过程的深入,城市群建设已成为中国推进新型城镇化战略的重要举措之一,长三角城市群作为我国发育程度最高的城市群,研究其城市扩展的时空规律对于政策制定、合理规划具有重要参考作用。本文利用长三角城市群1990—2010年间5个时期的城镇建设用地监测数据,选取首位度指数、年均扩展量、土地利用效率等指标,对比分析不同城市扩展随时间变化的过程特征。结果表明：20年来该城市群内城镇建设用地面积增加量超过8000 km2,各时段中2005—2010年扩展最为剧烈;城镇建设用地首位度指数逐步降低,该城市群建设用地规模呈现多中心化的趋势且正在强化;各城市城镇建设用地年均扩展量及土地利用效率随时间的变化轨迹呈现出明显的省内相似性和省际异质性;绝大部分城市城镇建设用地利用效率呈现出先升高后降低的趋势,1995年以来各城市城镇建设用地利用效率普遍显著降低,说明粗犷低效蔓延仍是该地区城市用地扩展的主要模式。     

Spin crossover and iron-rich silicate melt in the Earth's deep mantle

A melt has greater volume than a silicate solid of the same composition. But this difference diminishes at high pressure, and the possibility that a melt sufficiently enriched in the heavy element iron might then become more dense than solids at the pressures in the interior of the Earth (and other terrestrial bodies) has long been a source of considerable speculation. The occurrence of such dense silicate melts in the Earth's lowermost mantle would carry important consequences for its physical and chemical evolution and could provide a unifying model for explaining a variety of observed features in the core-mantle boundary region. Recent theoretical calculations combined with estimates of iron partitioning between (Mg,Fe)SiO(3) perovskite and melt at shallower mantle conditions suggest that melt is more dense than solids at pressures in the Earth's deepest mantle, consistent with analysis of shockwave experiments. Here we extend measurements of iron partitioning over the entire mantle pressure range, and find a precipitous change at pressures greater than ～76?GPa, resulting in strong iron enrichment in melts. Additional X-ray emission spectroscopy measurements on (Mg(0.95)Fe(0.05))SiO(3) glass indicate a spin collapse around 70?GPa, suggesting that the observed change in iron partitioning could be explained by a spin crossover of iron (from high-spin to low-spin) in silicate melt. These results imply that (Mg,Fe)SiO(3) liquid becomes more dense than coexisting solid at ～1,800?km depth in the lower mantle. Soon after the Earth's formation, the heat dissipated by accretion and internal differentiation could have produced a dense melt layer up to ～1,000?km in thickness underneath the solid mantle. We also infer that (Mg,Fe)SiO(3) perovskite is on the liquidus at deep mantle conditions, and predict that fractional crystallization of dense magma would have evolved towards an iron-rich and silicon-poor composition, consistent with seismic inferences of structures in the core-mantle boundary region.     

完全扩容图的点圈扩张性

目的讨论了完全扩容图的圈扩张性。阿勇嘎在2011年给出了完全扩容图的概念,完全扩容图是G□L（G）唯一的非平凡分支,其中L（G）是G的线图。方法利用归纳法对其进行讨论。结果与结论对于最小度大于2的连通且局部连通的完全扩容图,它的任一点由所在的一个6-圈经过若干次1或2-扩张,最后得到哈密顿圈。     

由胆矾精制五水硫酸铜实验的教学思考

就该实验中如何以诱导思考的方式启发学生对实验操作必要性的认识,提高学生分析问题、解决问题以及实验设计能力的培养提出了自己的看法。对导致学生实验失败的几种情况进行了分析。     

溴化锂制冷机溶液除铜技术

提出了一种能有效去除废旧LiBr溶液中铜杂质的方法.采用添加硫化钡并用稀HBr调节溶液的pH值和添加一种活性炭--硅藻土复合添加剂,通过搅拌、沉降、过滤,可使杂质铜的含量由原来的1200mg/L降至2～4mg/L,符合溴化锂制冷机(吸收式空调)国家标准关于LiBr溶液中铜含量的要求.     

诸葛亮的若干反面启思

诸葛亮为蜀汉政权的建立立下的汗马功劳,众所周知。但其后半生中,在荆州局势决策错误,不识大局不自量力,用人不当,不善授权,不善培养人才,赏罚不平,拒谏等九方面的过失,使得蜀汉最先灭亡,可见蜀汉“成也诸葛,败也诸葛”。