187Pt的高自旋态能级结构研究

利用在束γ谱学技术和 173Yb(18O, 4n) 熔合蒸发反应研究了 187Pt 的高自旋态能级结构。在 78 和 85 MeV 束流能量下进行了X-γ-t和γ-γ-t符合测量。实验观测到基于νi13/2，ν7/2−[503]，νi213/2νj, ν3/2−[512] 和ν1/2−[521] 组态的转动带，并且利用推转壳模型(CSM) 和总Routhian面(TRS) 模型对这些转动带的带交叉，形状共存等性质进行了解释。总Routhian面(TRS)计算表明νi13/2转动带具有显著的负γ形变；负宇称带具有近似长椭球的形变。通过比较带内B(M1)/B(E2)比率的实验值和由 Dönau 和 Frauendorf 的半经典公式得到的理论值，发现ν7/2−[503] 转动带在低转动频率下的带交叉是由一对 h9/2 质子顺排引起的

Heat capacities and thermodynamic functions of p-chlorobenzoic acid

The heat capacities of p-chlorobenzoic acid were measured in the temperature range from 80 to 580 K by means of an automatic adiabatic calorimeter equipped with a small sample cell of internal volume of 7.4cm(3). The construction and procedures of the calorimetric system were described in detail. The performance of this calorimetric apparatus was evaluated by heat capacity measurements on alpha-Al2O3. The deviations of experimental heat capacities from the corresponding smoothed values lie within +/-0.28 per cent, while the inaccuracy is within +/-0.40 per cent, compared with the recommended reference data in the whole experimental temperature range. A fusion transition at T = 512.280 K was found from the C-p-T curve of p-chlorobenzoic acid. The enthalpy and entropy of the phase transition, as well as the thermodynamic functions {G((T)) - G((298.15))}, {H-(T) - H-(298.15)} and {S-(T) - S-298.15}, were derived from the heat capacity data. The mass fraction purity of p-chlorobenzoic acid sample used in the present calorimetric study was determined to be 0.99935 by fraction melting approach. (C) 2002 Elsevier Science Ltd. All rights reserved.

秸秆还田对水溶性有机碳的影响

水溶性有机碳对农业土壤中的碳循环有着重要的作用。通过持续6年的田间试验来研究玉米秸秆还田对土壤水溶性有机碳的影响,共有3种处理:(1)对照;(2)粉碎还田;(3)覆盖还田。结果表明,在6年的秸秆还田试验中,秸秆还田能够增加土壤有机碳和水溶性有机碳的含量(P<0.05),主要是增加了大团聚体组分中有机碳和水溶性有机碳的含量。秸秆不同还田方式对土壤有机碳和水溶性有机碳并没有显著的影响,土壤水溶性有机碳和土壤有机碳有很好的相关性(R2=0.512)。

辽西半干旱区农田水肥耦合作用对春小麦产量的影响

最优饱和设计试验建立的春小麦产量回归数学模型表明 ,水分是影响辽西半干旱区春小麦产量最为重要的因子 ,但在自然降水条件下 ,灌水量上、下限分别为 45mm和 3 60mm时 ,N对春小麦产量影响更为敏感 ,其次为水与P因子 ,三因子对小麦产量影响统计分析达显著水平 ,并且其对小麦产量的影响符合报酬递减率 .获得最大利润时N、P和水三因素最佳经济配比模式为施N量 186kg·hm-2 ,施P量 63kg·hm-2 ,灌水量3 0 0mm ,在缺水条件下适量增施P肥有利于增强春小麦的抗旱作用

热电厂废水在库布其沙地农业利用的生态效应分析

采用野外现场生态调查、实验室分析和现场模拟相结合的方法,研究了电厂废水农业利用可能带来的环境问题。结果表明,以目前达拉特电厂的水质状况,在库布其沙地进行合理的农业利用,在可以预见的时间内(20a),不会导致土壤盐渍化和重金属污染现象的发生,因此,电厂废水的农业利用是可行的。

SHACAL-2算法的差分故障攻击

该文采用面向字的随机故障模型,结合差分分析技术,评估了SHACAL-2算法对差分故障攻击的安全性。结果显示:SHACAL-2算法对差分故障攻击是不免疫的。恢复出32 bit子密钥的平均复杂度为8个错误密文,完全恢复出512 bit密钥的复杂度为128个错误密文。

中国穿山甲细菌人工染色体文库的构建及其特征鉴定

鳞甲目 （Pholidota）作为真兽亚纲18个现生目之一，是理解哺乳动物系统分类和进化的一个关键类群。穿山甲的形态十分特殊，它的系统发生地位历来就是人们关注的对象，搞清穿山甲的系统发生地位将有助于理解和重建整个哺乳动物的系统发生过程。目前，中国穿山甲已被列入“哺乳动物基因组计划”24个待测序物种其中之一。细胞遗传学的研究表明中国穿山甲的核型具有多态性。 细菌人工染色体 （BAC）文库目前已成为基因组学研究领域的最为重要的研究工具之一。各种动植物细菌人工染色体文库的逐渐丰富为后基因组时代比较基因组研究奠定了良好的基础。中国穿山甲基因组DNA文库的构建将有力地促进穿山甲染色体演化、哺乳动物比较基因组学及其系统发育学的研究。 本研究在世界上首次成功地构建了一个具有约8倍基因组覆盖率的中国穿山甲细菌人工染色体文库。该基因组文库含有208,512个克隆，储存在543块384孔板中。对随机选取的171个克隆的Not1酶切和脉冲场电泳结果分析显示: 64.5%的克隆插入片段大小介于100-149 Kb之间， 75.6%的克隆插入片段大于100kb。平均插入片段大小为111.4Kb; 非重组克隆 （无插入片段）的比率为9.9%。同时，我们通过荧光原位杂交把105个BAC克隆定位到了中国穿山甲染色体上的特异区域, 构建了中国穿山甲的BAC细胞遗传学图谱。初步的染色体定位结果表明，BAC克隆在基因组中的分布没有偏向性。 中国穿山甲BAC文库的成功构建，丰富了哺乳动物基因组文库资源。该文库除有利于比较基因组研究之外，也为深化保护遗传学研究奠定了基础。BAC细胞遗传学图谱的构建，将为中国穿山甲全基因组测序中产生的序列重叠群在染色体上的定向和定位奠定基础。

Preparation and characterization of Gd2O3:Eu3+ luminescence nanotubes

The size controllable Gd2O3:Eu3+ luminescence nanotubes were successfully prepared using a simple method by coating gadolinium compounds on the carbon nanotubes and then firing the carbon nanotubes. The morphology of the obtained Gd2O3:Eu3+ nanotubes was determined by transmission electron microscopy (TEM). It was found that the obtained nanotubes have the outer diameters of similar to 100 nm, the inner diameters of similar to 50 nm, and the lengths of several tens of microns. The sizes of Gd2O3:Eu3+ nanotubes can be easily controlled by changing the reaction times and the concentration of reactants.

Synthesis and crystal structure of a novel compound: [H3PMo12O40][CO(NH2)(2)](3)center dot-5H(2)O

The title compound, [H3PMo12O40][CO(NH2)(2)](3). 5H(2)O, was synthesized and characterized by IR, C-13 NMR and X-ray diffraction. This is the first example of a urea-heteropoly acid species. Crystal data: monoclinic, C2/c, a = 17.790(4) Angstrom, b = 17.158(3) Angstrom, e = 25.512(5) Angstrom, beta = 100.65(3)degrees, V = 8514(3) Angstrom (3), Z = 6, R-1 = 0.0437, wR2 = 0. 1092. In the unit cell, the urea molecules occupy cavities in the polyoxometalate lattice ordered along b-axis. Water molecules occupy the space left by polyoxometalates, and urea. Polyoxometalate O atoms, the N atoms of urea and O atoms of water molecules are involved in hydrogen bonding. (C) 2001 Elsevier Science B.V. All rights reserved.

Catalytic oxidation of cyclohexene to cyclohexanone by a triple system in acidic aqueous acetonitrile medium

The catalytic oxidation of cyclohexene to cyclohexanone using Pd(OAc)(2)/HQ/FePc was investigated in an acidic aqueous solution of acetonitrile. The role of each component of this system in the oxidation of cyclohexene was explored by means of UV-VIS, IR, XPS spectroscopy and. cyclic voltammetry, respectively. Based on the experimental results, the mechanism of the oxidation of cyclohexene catalyzed by Pd(OAc)(2)/HQ/FePc was elucidated.

Catalysis of the rare earth containing mixed oxides Ln(2)CuO(4) in phenol hydroxylation

Mixed oxides Ln(2)CuO(4+/-lambda)(Ln = La, Pr, Nd, Sm, Gd) with K2NiF4 structure were prepared. Their crystal structures were studied with XRD and IR spectra. Meanwhile, the average valence of Cu ions and nonstoichiometric oxygen (lambda) were determined through chemical analyses. Catalysis of the above-mentioned mixed oxides in the phenol hydroxylation was investigated. Results show that the catalysis of these mixed oxides has close relation with their structures and composition. Substitution of A site atom in Ln(2)CuO(4+/-lambda) has a great influence on their catalysis in the phenol hydroxylation.