Synthesis and Characterization of Two Mononuclear Mn~Ⅲ Compounds with Mixed Schiff Base Ligands

Two mononuclear Mn compounds of Mn III (salen)(L 1) and Mn III (salen)(L 2) (H 2 salen=N,N-ethylenebis-(salicylideneaminato),L 1=4-(2-hydroxybenzylideneamino)benzoic acid and L 2=4-(2-hydroxybenzylideneamino)-2-hydroxybenzoic acid) have been prepared and characterized by X-ray crystallography.Both compounds crystallize in the monoclinic system,space group P2 1 /c with a=14.351(4),b=14.955(3),c=11.869(3) and β=91.529(3)° for 1;and those for 2:a=14.439(9),b=15.217(9),c=11.660(7) and β=91.648(1)°.The compounds have similar structures,in which the Mn III center adopts a distorted square-pyramidal geometry with the basal plane constructed by two N and two O atoms from the salen ligand and the apical position occupied by the carboxylate O atom from L 1 or L 2 ligand.The voltammetric behavior of the compounds is examined,which shows quasi-reversible one-electron reduction of Mn(Ⅲ) to Mn(Ⅱ).The reduction potentials of both compounds fall between-0.33 V [E 0 (O 2 /O 2 ·)] and 0.65 V [E 0 (1 O 2 /O 2 ·)],which suggest that 1 and 2 could be potential mimics of Mn-SOD.     

探测低动量粒子的高精度中心漂移室性能的估算

分析估算了用于探测低动量带电粒子的高精度中心漂移室(CDC)的动量分辨率与电离能损,对低动量带电粒子的动量测量以及利用dE/dx识别粒子的能力进行了讨论,并探讨了CDC对两个典型过程的探测性能.     

一个使用氦基混合气的小单元漂移室的实验研究

利用宇宙线分别研究了一个小单元漂移室在He/C3H8(60/40)和He/CH4(60/40)两种氦基混合气下的性能.作为比较还测试了在Ar/CO2/CH4(89/10/1)混合气下的性能.研究表明上述氦基混合气的空间分辨和dE/dx分辨好于Ar/CO2/CH4(89/10/1)混合气.使用He/C8H8(60/40)可以获得110μm的空间分辨,在30—40次取样下dE/dx分辨可以达到6%—7%.     

7050铝合金等通道转角挤压过程中显微结构和力学性能演化的小角x射线散射研究

采用三种等通道转角挤压（ECAP）与热处理相结合的工艺制备了超高强度细晶7050铝合金， 应用小角x射线散射技术定量地分析了ECAP过程中显微结构参数的变化情况，合理地解释了E CAP过程中力学性能的变化，揭示了合金强化机理. 研究发现，“固溶淬火＋ECAP＋时效” 工艺是获得高性能7050铝合金的合适工艺，可以使7050铝合金的抗拉强度提高到677 MPa， 延伸率保持在15％左右. 关键词： 7050铝合金 小角x射线散射 显微结构 力学性能     

含环烷巯基配体的Fe_4S_4类立方烷簇合物的合成和结构表征

报道了 2个含烷巯基配体的Fe4S4类立方烷簇合物 ,它们在氯化亚铁 ,四硫代金属酸盐及环烷硫醇组成的反应体系中生成 ,化合物的结构参数分别为 :[PhCH2 NMe3 ]2 [Fe4S4(SC5 H9) 4](Ⅰ ) ,属单斜晶系 ,空间群P2 1/c,a =1 .6 32 7( 4)nm ,b=1 .1 2 2 9( 3)nm ,c=2 .80 2 5 ( 1 0 )nm ,β =94.6 3( 2 )°,Z =4,R =0 .0 74;(Et4N) 2 [Fe4S4(SC6H11) 4](Ⅱ ) ,,属四方晶系 ,空间群I42m ,a=1 .1 6 70 5 ( 9)nm ,b=1 .1 6 70 6 ( 2 )nm ,c=2 .0 6 32 6 ( 5 )nm ,Z =2 ,Dcalc=1 .2 7g/cm3 ,R =0 .0 78.环烷巯基配体的引入没有引起Fe4S4核心结构的明显变化 ,同时讨论了阳离子对Fe4S4簇阴离子结构对称性的影响     

Synthesis and Crystal Structure of a 2D Cu Framework Constructed from Dinuclear Building Units

A novel 2D Cu coordination polymer [Cu4(pca)4(H2O)2(DMSO)2·2DMSO·2H2O]n(2, H2 pca = pyrazole-3-carboxylic acid) has been prepared by dissolving a dinuclear Cu complex Cu2(py)3(pca)2(H2O)·(H2O)(1) in DMSO solution and structurally characterized by X-ray diffraction. The polymer crystallizes in space group P1 with a = 9.538(3), b = 9.714(3), c = 10.765(3) A, α = 86.492(6), β = 84.007(7), γ = 82.592(6)o, Mr = 1079.04, V = 982.4(5) A3, Z = 1, Dc = 1.824 g/cm3, μ = 2.425 mm-1 and F(000) = 548. The final refinement gave R = 0.0785 and w R = 0.1940 for 2787 reflections with I 2σ(I). The structure of 2 consists of Cu4(pca)4(H2O)2(DMSO)2·2DMSO·2H2O units, which can be viewed as two dinuclear subunits of Cu2(pca)2(H2O)2 and Cu2(pca)2(DMSO)2 connected to each other alternately, with solvent DMSO and H2 O molecules around. The framework features a grid-like topology, with the walls of the grids composed of Cu4(pca)4 units, and the coordinated solvent molecules trapped in the grids.     

He/C3H8(60/40)气体增益的实验研究

利用正比计数管测量了氦基混合气体He/C3H8(60/40)在55Fe 5.9keV X射线下的气体增益，并对气体增益随高压、温度、气压及气体比分的变化作了研究. 作为比较还对He/CH4(60/40)及Ar/CO2/CH4(89/10/1)混合气体进行了相应的测量.     

STUDIES ON SYNTHESES OF MoFe_3S_4 CUBANE-LIKE CLUSTER COMPOUNDS

The features of synthetic processes are described on the basis of the studies of the syntheses of MoFe_3S_4 cubane-like cluster compounds either by self-assembly reactions or by the conversion of linear clusters. The redox properties and the structure of ligands as well as the stoichiometry of reactants have obvious effects upon the core oxidation state and the structure of products. It is indicated that the self-assembly reaction may pass through a combination process oflinear cluster intermediates having structural unit (M,M'=Mo) Fe).     

L3强子量能器第一个模块正比室的研制

本文报导L3强子量能器第一个模块60个正比室的研制和性能测试.在充以Ar(80%)+CO₂(20%)混合气条件下,室计数率坪长125V,坪坡度3.4%/100V.输出脉冲具有良好的均匀性.长时间的高压"锻炼"能使暗电流减小.由正比室装配成的强子量能器模块,在CERN SPS试验束上进行了性能测试.取得了满意的结果.     

Synthesis and structure of linear hexanuclear manganese (Ⅱ)benzoate cluster

From a reaction system including benzoic acid and Mn(NO3)2 in alkali medium, two hexanuclear manganese benzoate cluster compounds have been synthesized. A compound [Et4N]2[Mn6(PhCOO)14] has been structurally characterized, which contains hexanuclear Mn11 moieties extending unlimitedly to form one-dimensional linear structure. Carboxyl oxygen atoms are bridged in variety of modes to the Mn atoms, forming an arrangement like a sinusoid for the Mn atoms. The structural parameters of these compounds were compared with the data obtained from EXAFS determination for the Mn cluster in the OEC of PS11, supporting that the coordination sphere of the Mn site in the OEC may contain carboxyl bridges. The possible combination modes between the carboxyl group and the Mn atoms have been suggested. The NMR signals exhibit widening and shift produced by the influence of the paramagnetic Mn" sites. The red-shift of the absorption in IR spectrum was observed to be attributed to the coordination of the carboxyl group to the Mn