Y2Ba1Cu1O5-δ掺杂对Y1Ba2Cu3O7-δ的超导电性及其晶格结构的影响

本文采用固相反应法成功制备出一系列Y123与Y211的摩尔比为1：x（x=0、0．14、0．27、0．3、0．35、0．4、0．45、0．47、0．5、0．8、1．18）的样品．实验结果表明：在0．35≤x≤0．5范围内,Y123的起始转变温度Tonset临界转变温度Tc以及转变宽度△Tc都在x=0．47出现了拐点,这...     

高压对大块（PrNd）xAl0．6Nb0．5Cu0．15B1．05Fe97．7-x合金微观结构和性能的影响冰

经配料、熔炼、制粉、成型和烧结后制备了（PrNd）xAl0．6Nb0．5Cu0．15B1．05Fe97．7-x（质量百分比）合金,将该合金分别采用1．5GPa和3．0GPa的压强进行压制,研究了此高压对其显微结构和磁性能的影响．分析发现,该块状合金承受的压强越高,其外观和微观结构破坏越严重,抗弯强度也会降低,但高温抗氧化性能却有一定程度的提高．与没有经过高压处理的磁体相比,经过1．5GPa和3．0GPa高压的样品最大磁能积分别提高了7．69kJ．m^-1和0．94kJ．m^-1,剩余磁通密度分别提高了0．02T和0．01L内禀矫顽力分别提高了20．06kA．m-1和30．33kA．m^-1．结果表明,高压对块状NdFeB烧结磁体的显微结构和力学性能及磁性能均有一定的影响．     

LaNi4．5Al0．5储氢合金固溶体的第一性原理分析

从第一性原理出发，基于广义梯度近似密度泛函和全势线性缎加平面波方法（FLAPW），对LaNi4．5Al0．5储氢合金固溶体相α-LaNi4．5Al0．5H0.5的晶体结构、电荷密度和态密度等特征进行了研究．对α-LaNi4．5Al0．5H0.5从能量角度计算得出H原子最可能占据6m格位，并给出了态密度（DOS）和电荷密度图，分析了H与Al之间的相互作用，以及H的加入对固溶体性质的影响。计算结果与实验值符合的相当好．     

掺钬镱离子的氟氧化物玻璃陶瓷的一级和二级红外量子剪裁的研究

本文报道了掺钬镱离子的氟氧化物玻璃陶瓷的一级和二级红外量子剪裁的比较研究．研究发现当0G5能级到0＆能级及之间的能级被激发的时候,大多数的粒子数容易无辐射弛豫到（5F4^5S2）能级．在（0F40＆）能级,由很强的ET7-ETaYb{5F4（Ho）→5I6（Ho）,2F7／2（Yb）→2F5/2（Yb））交叉能量传递渠道,导致Ho3＋离子的粒子数被无损耗的交叉能量传递到5I6能级,同时Yb3＋离子从基态2F7／2能级被激发到2F5/2能级,它导致了两个能被晶体硅有效吸收的红外光子,即一个（1153am,1188am）的红外光子和另一个（973．0nm,1002．0nm）的红外光子,因此出现了显著的双光子一级红外量子剪裁．最后,该文计算了Ho（0．5）Yb（1）：FOV和Ho（0．5）Yb（10．5）：FOV的交叉能量传递效率为ηtr,1％Yb（5FS2）=29．2％,‰,10．5％Yb（5F4^5S2）=99．2％和它们的共合作能量传递效率为ηtr,1％Yb（5F3）=4．18％,ηtr,10．5％Yb（5F3）=75．3％;而它们的双光子量子剪裁效率的理论上限值依次为ηCR,1％Yb（5F4^5S2）=129．2％,ηCR,10．5％Yb（5F4^5S2）=199．2％和ηCO,1％Yb（5F3）=104．18％,ηCO,10.5％Yb（5F3）=175．3％．因此发现了一级红外量子剪裁有比二级红外量子剪裁高较多的概率．该项研究对太阳能电池效率的提高很有意义．     

La0．5Er0．2Ca0．3Mno3低温磁电阻效应的实验研究

本文简要介绍对La0．5Er0．2Ca0．3Mno3进行低温电磁测量的实验过程,研究掺杂后复合体系的磁电阻效应。     

ICP-AES测定饮用水源中的Cu、Mn、Pb、Cd、Zn

用ICP－AES法同时测定饮用水源中的Cu、Mn、Pb、Cd、Zn等重金属元素，具有基体效应小、测量范围宽等优点。检出限为0．2－4．0μg/L，回收率为91．5％－103．9％，相对标准偏差为0．29％－1．5％，测定密码样与实际样品，结果令人满意。     

多色高分子薄膜电致发光器件

采用多层高分子发光层和电极层结构实现了在同一ITO基片上产生红、绿、蓝三基色发光。得到电压阈值分别为：蓝色：2．5V,绿色：2．5V,红色：1．8V;发光量子效率：蓝色：2．5％,绿色：1．7％,红色：1．2％：色度坐标分别为：蓝色：(0．16,0．16),绿色：(0．34,0．58),红色：(0．60,0．39)。这种多层薄膜结构可能成为实现高分子彩色发光显示的新途径。     

MgxB2起始成分对不可逆场和临界电流密度的影响

我们用固相反应法成功合成了MgrB2（0．5≤x≤1．3）系列样品，并对其结构，临界电流密度（Jc）和不可逆场（Hirr）进行了研究．实验结果表明，随着x增大晶格常数α逐渐增大，而晶格常数c在x=0．9左右达到最大值．所有x〉0．5的样品在零场下的Jc值都在10^6A／cm^2左右．然而在高磁场下，Mg缺位的样品的Jc值要比Mg富足的样品的Jc值大．20K时．Mg0．8B2样品的不可逆场达到最大值5．2T，比MgB2样品要高出0．8T．研究表明，高磁场下Hirr和Jc的增大可能与MgB4纳米粒子的形成有关．     

Na0．75Co1-xRuxO2体系中的金属-绝缘体相变

在采用固相反应法成功制备单相Na0．75Co1-xRuxO2（0≤x≤0．5）样品的基础上，对其结构、输运性质和磁性质进行了系统研究．结果表明，x≤0．5的样品仍保持单相。样品的晶格参数随着Ru替代浓度x值的增加逐渐增大，说明在该体系中，Ru能均匀地替代Co．对于x=0的样品，在整个测量温区内，其电阻率-温度关系呈现典型的金属行为；x=0．01样品在T=37K附近发生了金属-绝缘体相变；而x≥0．02的所有样品，整个测量温区内均为半导体．与x=0样品相比较．x=0．1样品在30K时的电阻率增大了5个数量级．我们认为该体系在x=0．01附近发生的金属-绝缘体（MI）相变，起源于CoO2层的无序导致的电子的Anderson局域化．对于所有样品，在2K以上均没有观测到长程磁有序。其磁化率在100K以上均满足居里-外斯定律，同时对该体系的磁化率结果进行了详细讨论．     

高温高压下Ba_(1-x)La_xTiO_3(x=0.0-0.5)的合成与结构相变的研究(英文)

本文首次采用高温高压固相反应法合成类钙钛矿化合物Ba1－xLaxTiO3（x＝0．0，0．1，0．2，0．3，0．4，0．5）。XRD谱的测量结果表明，在压力为2．8GPa，温度为850℃下，稀土La在BaTiO3中的替代导致结构从立方到四方到正交的结构转变，因此，Ba1－xLaxTiO3体系体现结构转变规律和丰富的物相结构。     

Influence of Solvent Polarity and Viscosity on Nonradiative Processes in Oligothiophenes with Intramolecular Charge Transfer

By the methods of luminescence, picosecond spectroscopy, and quantumchemical calculations the mechanisms of electron excitation energy deactivation in some oligothiophenes with intramolecular charge transfer depending on the solvent polarity and viscosity have been investigated. While for 2Npiperidino5(2,2dicyanovinyl)thiophene (PDCVT) the main channel of nonradiative deactivation is the transition to a lower intermediate state with a twisted double bond controlled by the medium viscosity, in the case of (E){2[25piperidino2thienyl]6(trifluoridemethyl)4H4pyranylidene}propanedinitryl (PTFDN) fluorescence quenching is initiated by the solvent polarity. For two other oligothiophenes, 2Npiperidino5cyanothiophene (PCT) and 2Npiperidino5cyanoterthiophene (PCTT), differing in the length of the thiophene chain, we have revealed, along with the effective quenching of fluorescence in shortchain PCT (independent of the solvent polarity and viscosity), an increase in the radiation capacity in PCTT with increasing polarity of the solvent. The possible mechanisms of nonradiative deactivation in the investigated oligothiophenes are discussed.     

Ru/WCoCN as a seedless Cu barrier system for advanced Cu metallization

The properties of Ru(5 nm)/WCoCN(5 nm) stacked layers as a seedless Cu barrier system has been investigated. Its barrier properties compared to single 10 nm Ru film were investigated by sheet resistances, X-ray diffraction patterns, transmission electron microscopy, energy dispersive spectrometry spot analysis, line scans, and leakage currents. Thermal stability of the Ru(5 nm)/WCoCN(5 nm) improved by over 100 °C than that of Ru(10 nm) barrier. The results show that Ru(5 nm)/WCoCN(5 nm) can effectively block Cu diffusion up to 600 °C for 30 min. The Ru(5 nm)/WCoCN(5 nm) bilayer is a great Cu barrier candidate for seedless Cu interconnects.     

SryBa1－yFCl0.5Br0.5:Sm2+在光谱

本文对无机光谱烧孔系列材料SryBa1－yFCl0.5Br0.5:Sm2+中不同组份的样品(y=0,0.25.0.5,0.75.1.00)4f5d能带的激发光谱、不同温度下5D2、5D1、5D0→7F0跃迁的荧光衰减进行了测量,研究了组份的变化对4f5d能带的位置,5D2、5D1、5D0→7F0跃迁的几率和烧孔效率的影响,并得出结论:在该系列材料中,随组份y的增加,4f5d带与5DJ能级更加接近,5D0→7F0的电子跃迁几率增大,烧孔效率提高。     

К ТЕОРИИ СПОНТАННОЙ Н АМАГНИЧЕННОСТИ ТОНКИХ СЛОЕВ. II. ЧАСТЬ)

- , . - . - - . , . 1956 .     

Ultra-high piezoelectric response in 〈<Emphasis Type="Bold">110</Emphasis>〉- oriented polydomain Pb(Mg<Subscript>1/3</Subscript>Nb<Subscript>2/3</Subscript>)O<Subscript>3</Subscript>- PbTiO<Subscript>3</Subscript> single crystals

The piezoelectric constant and electromechanical coupling coefficients of 110-oriented polydomain0.71Pb(Mg_1/3Nb_2/3)O₃-0.29PbTiO₃ single crystals were determined experimentally by using resonance methods. It was confirmed that the single-crystal system has large electromechanical coupling coefficients k₃₃ (91%), k₃₃ (83%), and k₃₁ (81%), and piezoelectric constant d₃₃ (1400 pC/N), which are comparable to those of 001-oriented crystals, and we also found that the values of k₃₃ and k₃₁ are sensitive to the cuts of the crystals. X-ray-diffraction measurements on 110-oriented crystals have shown that the origin of the high piezoelectric response should be attributed to the orthorhombic distortion. Our results show that the 110-oriented crystals are also promising for a wide range of electromechanical transducer applications, since the 110-oriented crystals can be grown from 110-oriented seed crystals in the modified Bridgman technique. PACS 77.80.Bh; 77.84.Dy; 77.65.Bn     

Dependence of the strain energies on grain orientations in HCP metal films

A thin polycrystalline film bonded tightly to a thick substrate of different thermal expansion coefficients will experience thermal strain when the temperature is changed. Calculations of the strain energies for grains having various crystallographic orientations (h k l) relative to the film surface were made for a polycrystalline film composed of the close-packed hexagonal (HCP) metal Be, Cd, Co, Hf, Mg, Re, Ru, Sc, Ti, Y, Zr and Zn, respectively. From strain energy minimization, the (0 0 1), (0 1 3), (0 4 5), (1 2 3), (2 5 8), (0 5 7), (0 3 5), (0 5 7), (0 1 0), (5 5 8), (1 4 7) and (0 0 1) textures should be favorable in Be, Cd, Co, Hf, Mg, Re, Ru, Sc, Ti, Y, Zr and Zn film, respectively.     

The dissimilar twins - a comparative, site-selective in situ study of CO adsorption and desorption on Pt(3 2 2) and Pt(3 5 5)

The adsorption and desorption of CO on stepped Pt(3 2 2) = Pt(S)-[5(1 1 1) × (1 0 0)] and Pt(3 5 5) = Pt(S)-[5(1 1 1) × (1 1 1)] were investigated using in situ high-resolution X-ray photoelectron spectroscopy at BESSY II, which allows to clearly distinguish between different step and terrace adsorption sites. For the two surfaces, with the same nominal terrace width of five atomic rows, but different step orientation, significant differences are observed. While for Pt(3 5 5) CO adsorption at steps only occurs at on-top sites, on Pt(3 2 2) both step on-top and bridge sites are occupied, albeit with a significantly lower coverage (0.07 vs. 0.13 ML at 200 K). On both surfaces terrace sites are only occupied when the step sites are almost saturated confirming the enhanced binding energy at step sites. CO adsorbed at the (1 1 1) steps on Pt(3 5 5) is more strongly bound than on the (1 0 0) steps on Pt(3 2 2), which is attributed to the different electronic and geometric structure of the steps. The relative occupation of terrace and step sites at a given coverage remains the same between 120 and 290 K on Pt(3 5 5) K, but shows major changes on Pt(3 2 2), between step on-top and bridge sites as well as terrace on-top and bridge sites. On Pt(3 5 5) a smaller CO terrace coverage is found (0.36 vs. 0.40 ML on Pt(3 2 2) at 200 K), mainly due to the lower occupation of terrace bridge sites. For Pt(3 2 2), an ordered adsorbate phase is deduced from a c(4 × 2)-like LEED pattern, which indicates adsorbate order beyond the extension of a single terrace. A model for this structure is proposed.     

(Ce,Gd,Mn)MgB5O10磷光体的合成及其发光

本文采用固相反应的方法合成了一系列(Ce,Gd,Mn)MgB5O10磷光体。观察到合成温度、灼烧时间、原料配比对磷光体的形成和发光亮度有重要影响。X射线衍射分析表明,磷光体结构与LaMgB5O10相同,属单斜晶系、空间群P21/c。用EPR确定了磷光体中锰离子为二价。测定了(Ce0.2La0.2)MgB5O10,(Gd0.7La0.3)MgB5O10,(Mn0.05La0.95)MgB5O10,(Ce0.2Mn0.05La0.75)MgB5O10,(Gd0.95Mn0.05)MgB5O10、(Ce0.2Gd0.8)MgB5O10和(Ce0.2Gd0.75Mn0.05)MgB5O15等磷光体的光谱。根据光谱数据讨论了(Ce0.2Gd0.75Mn0.05)MgB5O10磷光体中能量传递过程为:Ce3+→Mn2+,Gd3+→Mn2+以及Ce3+→Gd3+→Mn2+,其中Ce3+离子可将能量高效地传递给Gd3+,Gd3+离子起着中间体的作用。     

Uniqueness of Gibbs State for Non-Ideal Gas in ℝd: The Case of Multibody Interaction

We study the question of existence and uniqueness of non-ideal gas in ^d with multi-body interactions among its particles. For each k-tuple of the gas particles, 2km ₀<, their interaction is represented by a potential function _k of a finite range. We introduce a stabilizing potential function , such that (x ₁,..., ) grows sufficiently fast, when diam{x ₁,..., } shrinks to 0. Our results hold under the assumption that at least one of the potential functions is stabilizing, which causes a sufficiently strong repulsive force. We prove that (i) for any temperature there exists at least one Gibbs field, and (ii) there exists exactly one Gibbs field at sufficiently high temperature, such that for any >0, C(V ₀)< for all volumes V smaller than a certain fixed finite volume V ₀. The proofs use the criterion of the uniqueness of Gibbs field in non-compact case developed in ref. 4, and the technique employed in ref. 1 for studying a gas with pair interaction.     

ВлИьНИЕ стАцИОНАРНО гО РАсслОЕНИь НА ДВИж УЩИЕсь слОИ В тлЕУЩЕМ РАжРьД Е B Ne

The paper describes a new experimentally found phenomenon of the effect of standing stratification on the parameters of moving striations in the positive column of a glow discharge.

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. . M. Hobaky