Crystal structure of the addition compound of N,N′-bi(2-pyridylmethyl)-oxamide and complex of manganese with 1,10-phenanthroline

The structure of the addition compound, Mn(phen)₃(PMoxdH₂)(ClO₄)₂ was established by X-ray crystallography, where PMoxdH₂ is N,N-bi(2-pyridylmethyl)-oxamide. Six nitrogen atoms of the three 1,10-phenanthroline bind to the manganese ion and the oxygen atom of PMoxdH₂ is uncoordinated. The addition compound crystallizes in the monoclinic space group C2/c, with lattice parameters a = 23.780(6), b = 11.948(5), c = 18.466(6) Å, = 117.38(3)°, V = 4659(3) ų, and Z = 4.     

可拆分有调整时间的平行机排序问题的一个算法

考虑有独立调整时间的同型号平行机排序问题,极小化最迟完工时间,产品允许拆分,同一产品被拆分后各部分可以在不同机器上同时加工,该问题是ＮＰ－ｈａｒｄ问题。本文首先给出该问题的一个启发式算法ＭＬ,然后证明了其最坏情况估计不超过７／４－１／ｍ（ｍ≥２）。     

Sm2-xCexCuO4的物性研究

制备了Sm2-xCexCuO4的多晶样品.X-射线粉末衍射结果表明,该系列样品为K2NiF4214结构,当0.090.17时,为T'相.电阻率测量在0.15,0.17,0.19样品上观测到超导转变.最高Tc对应于x=0.17为13.6K,均远低于(Pr0.8La1.2)1.85Ce1.2CuO4 的超导转变温度(30K).这是由于该系列样品在远高于超导转变温度时就存在更强的载流子局域化效应.磁化率测量结果表明x=0.17的样品为体超导.该体系样品的Tc低、抗磁信号小与载流子的强局域化效应有关.热电势测量结果表明,在最佳超导组份附近斜率改变符号,欠掺杂区域载流子为电子型,过掺杂区域载流子为空穴型.     

Mode Distribution and Bandwidth Characteristic of Arbitrarily Trapezoidal-Groove Guide for Millimeter Waves

The modes TE and TM of arbitrarily trapezoidal-groove guide are analyzed by using the mode-matching method. The mode TE₁₁ is the dominant mode of the trapezoidal-groove guide under different conditions. The bandwidth characteristic and the operation condition for the single dominant mode are discussed. The obtained conclusions are of very important significance in theoretical study and practical application of trapeziodal-groove guides for millimeter waves.     

Structural and electrical properties of γ-alumina - lithium sulphate films

Li₂SO₄ as a model ionic conductor has received very much attention over several decades. Especially, in recent years Li₂SO₄ and Li₂SO₄-Al₂O₃ have been mentioned as promising proton conducting electrolytes for applications such as intermediate temperature fuel cells and novel cogeneration systems regarding H₂S handling devices. This has encouraged us to strive towards further improvement of the properties of the materials to meet the demands of the applications. In order to improve the properties of this system, a new process, a suspension technique, has been recently developed to prepare nanostructured powder and thin film Li₂SO₄-Al₂O₃ membranes. The powders and thin films have a well crystallised structure composed of two phases, Li₂SO₄ and γ-Al₂O₃, and excellent mechanical strength. The thin film thickness is in the scale of a few to several mm with a smooth and shining surface and a homogeneous macroscopic structure. It is a very interesting phenomenon that all samples show no significant conductivity increase at the temperature of the phase transition (∼ 577 °C) from β to α phase of pure Li₂SO₄. This transition has important significance for applications. The conductivity of the two-phase film materials has been greatly enhanced, where the xLi₂SO₄-(1-x)Al₂O₃ (x=58) sample shows the highest conductivity, about 1 S/cm at 600 °C; the activation energy decreases with increasing Li₂SO₄ content. These results agree with the so called composite effect for the conductivity enhancement observed earlier for two-phase bulk materials. Based on the four-step proton conducting mechanism in sulphate-based materials, this work may propose a new mechanism. The protons might jump in a water network associated with the water molecular re-orientation, which is accompanied with the single proton jump of the four-step transportation among SO ₄ ²⁻ groups from one Li₂SO₄ molecule to another. The former mechanism occur in the interfacial region between the Li₂SO₄ and the Al₂O₃ grains, while the latter occur in the bulk of the Li₂SO₄ grains. These thin film materials are intended for use as proton conducting ceramic membranes in applications such as desulphurisation and fuel cell co-generation plants. Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998.     

Bright Red Organic Electroluminescent Devices Based on a Soluble Rare Earth Complex Eu(TTA)_3 Phen

ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｇａｎｉｃｅｌｅｃｔｒｏｌｕｍｉｎｅｓｃｅｎｔ（ＥＬ）ｄｅｖｉｃｅｓｈａｖｅｂｅｃｏｍｅｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｓｕｂ－ｊｅｃｔｓｂｅｃａｕｓｅｏｆｔｈｅｉｒｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎａｓｌ...     

一种新的Eu3+配合物有机薄膜电致发光

自从C. W. Tang[1]百次发表高效、高亮度双层结构有机薄膜电致发光(EL)器件以来,由于其驱动电压低、可做成大面积及制作工艺简单等优点,使其在平板显示和显像领域具有巨大应用潜力而成为研究热点.可是大多数有机小分子和聚合物材料制作的有机薄膜电致发光器件的发射光谱谱带很宽,半高宽一般在100nm-200nm,色纯度不好,不利于显示和显像.于是寻找场致发光谱带窄、亮度高的有机材料就显得非常重要.     

产品开发决策的灵敏性分析

文章着重研究了市场需求服从正态分布时参数估计误差变化对产品开发决策正确性的影响。通过实例分析，得到了处理这类问题的方法。文章进而给出了需求为有限方差与数学期望的一般随机量的处理方法，还给出了对Poisson变量的分析公式。     

Path integration of the harmonic oscillator with a two-time quadratic action

Path integration of the harmonic oscillator with a two-time quadratic action characterizing memory effects is given in terms of the solutions of some integrodifferential equations. The exact propagator in closed form is then obtained for the specific kernel introduced by Feynman in the polaron problem.     

Creating Ioffe-Pritchard micro-traps from permanent magnetic film with in-plane magnetization

We present designs for Ioffe-Pritchard type magnetic traps using planar patterns of hard magnetic material. Two samples with different pattern designs were produced by spark erosion of 40 μm thick FePt foil. The pattern on the first sample yields calculated axial and radial trap frequencies of 51 Hz and 6.8 kHz, respectively. For the second sample the calculated frequencies are 34 Hz and 11 kHz. The structures were used successfully as a magneto-optical trap for ⁸⁷Rb and loaded as a magnetic trap. A third design, based on lithographically patterned 250 nm thick FePt film on a Si substrate, yields an array of 19 traps with calculated axial and radial trap frequencies of 1.5 kHz and 110 kHz, respectively.