多阴离子和铜磷酸盐为基元的杂化材料的合成、结构和性质

本文采用水热法合成了一个新的金属有机-无机杂化化合物 [Cu₄(phen)₄(HPO₄)₂(H₂O)₂(OH)₂][HPMo₁₂O₄₀]·H₂O (1) ( phen=邻菲咯啉)。通过元素分析、红外光谱、热重分析、X-射线单晶衍射对其进行了结构表征。化合物1是由四核铜磷酸盐、Keggin阴离子和晶格水分子组成。四核铜磷酸盐和多阴离子之间通过弱的M…O相互作用形成二维结构(M=Cu, Mo), 该二维结构通过氢键和π-π相互作用形成三维超分子框架,还对化合物1的电化学和电催化性质进行了研究。     

Syntheses, Crystal Structures and Electrochemical Properties of Three New One-dimensional Compounds Based on the BiW9O33 Unit

Three new one-dimensional compounds [{NaO2(H2O)2}2{(M(H2O)2)2(WO2)2- (BiW9O33)2}]·16H3O+·XH2O (M = MnII (1), CoII (2), NiII (3)) have been synthesized in an aqueous solution, and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. These tungstobismuthates reveal that one common feature is the trivacant β-B-BiW9O33 Keggin fragment as the structural building unit. Two β-B-BiW9O33 units are connected by two WO2 groups with further stabilization by the addition of two M(H2O)22+ groups leading to the M2Bi2W20 anions, which are linked in a 1-D chain by bisodium cluster. Electrochemical analyses show that compounds 1-3 display unique redox properties and good electrocatalytic activity to reduce nitrite.     

The influence of nano-particle tracers on the slip length measurements by microPTV

Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry (microPIV/PTV) measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hy-pothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hy-drophilic wall (z = 0.25-1.5 μm) with two sizes of tracer particles (φ 50 nm and φ200 nm). The experimental results indicate that, at less than 1 μm from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of φ200 nm particles to 48% of φ50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hy-drophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall.     

流动注射-鲁米诺-Ag(Ⅲ)化学发光法测定金银花中绿原酸

碱性介质中绿原酸对鲁米诺-Ag(Ⅲ)化学发光体系有显著增敏作用,在一定范围内,绿原酸的浓度与化学发光强度成正比.据此,结合流动注射技术,建立了绿原酸化学发光测定的新方法,并研究了影响化学发光强度的因素.在最优条件下测得方法的检出限为0.50μg/L,线性范围1.0-200.0μg/L.对25.0μg/L的绿原酸进行平行...     

Influence of pH and organic ligands on the supramolecular network based on molybdenum phosphate/strontium chemistry

Three supramolecular materials based on different poly(oxomolybdophosphate) clusters, (H(2)imi)(6)(Himi)(4)[{Sr(H(2)O)(4)}(2){Sr ? P(6)Mo(4)(V)Mo(14)(VI)O(73)}(2)]·17H(2)O (1), (H(2)(4,4'-bpy))(2)[Cu(2)Sr(2)Mo(12)O(24)·(OH)(6)(H(2)O)(6)(H(2)PO(4))(2)(HPO(4))(2)(PO(4))(4)]·5H(2)O (2), and (H(2)bim)(H(2)bim)[SrP(2)Mo(5)O(23)(H(2)O)(3)]·2H(2)O (3) (imi = imidazole, 4,4'-bpy = 4,4'-bipyridine, and bim = 2,2'-biimidazole), have been hydrothermally synthesized and structurally characterized by the elemental analysis, TG, IR, UV-vis, XPS and the single-crystal X-ray diffraction. Compound 1 is made up of unusual basket-shape [Sr ? P(6)Mo(18)O(73)](10-) cages linked by [Sr(H(2)O)(4)](2+) fragments to yield unprecedented dimeric chains, which represent the first 1-D assemblies of basket-type POMs. Compound 2 exhibits a novel string constructed from sandwich-like [Cu(P(4)Mo(6)O(31))(2)] units and {Sr(2)Cu} trinuclear linkers. Compound 3 is the first chain of Strandberg-type polyoxoanions connected by Sr(2+) cations. All the 1-D chains are further packed into various 3-D supramolecular assemblies via strong hydrogen-bonding interactions. The electrochemical and electrocatalysis behavior of 1, 2, and 3-CPE have been investigated in detail.     

Synthesis,Structure and Electrochemical Property of a Supramolecular Compound（H2en）2[Cu（en）2（H3O）2][Mo8O28]

A supramolecular compound(H2en)2[Cu(en)2(H3O)2][Mo8O28](en=ethylenediamine) was hydrothermally prepared and confirmed by elemental analysis and TG analysis.Single-crystal X-ray analysis reveals that the crystal crystallizes in the triclinic system,space group P1 with a=9.4635(4),b=9.8645(5),c=10.9794(5),α=69.2050(10),β=72.3730(10),γ=78.4510(10)o,Mr=1559.55,V=908.24(7)3,Z=1,Dc=2.851 g/m3,F(000)=749,μ=3.350 mm-1,S=1.000,the final R=0.0217 and wR=0.0567.The compound consists of(H2en)2+,[Mo8O28]8-anion and [Cu(en)2(H3O)2]2+ cations and constructs a 3D supramolecular structure through hydrogen bonds between the nitrogen atoms from en of [Cu(en)2(H3O)2]4+ fragments and the terminal oxygen atoms from the [Mo8O28]8-polyoxoanions.The electrochemical behavior of this compound has been studied in detail based on a solid bulk modified carbon paste electrode of compound(CPE).     

Ground movement analysis in deep iron mine using fuzzy probability theory

The analysis of the ground movements due to underground mining operation is one of the many important problems of rock mass mechanics. It is difficult to calculate the ground movement due to deep underground mining of iron ore accurately because of the complexity of the problems. In this paper, the application is described of the fuzzy probability measures to the analysis of ground movements. Based on the definition of the fuzzy probability measure, the theories for the two- and three-dimensional problems are developed and are applied to the analysis of ground movements duo to underground deep underground mining of iron ore.     

傅里叶变换红外光谱诊断地中海贫血症

为建立简单快速的地中海贫血诊断方法,本研究探讨了以傅里叶变换红外光谱结合水平衰减全反射(FTIR-HATR)技术在地中海贫血诊断中的制样方法及光谱的数据处理方法.在制样预处理中,通过对样品进行稀释并干燥成膜消除水分子对光谱吸收干扰,保持ATR光谱中各波长对样品的穿透深度一致.结果表明,当1652 cm-1吸收度小于1.5时(即透射率T小于4%时),各波峰强度与血红蛋白浓度呈良好的线性关系(r>0.995)及实验重复性(RSD<4%).在数据处理上,改进的相对强度方法用于800～1780 cm-1和2480～3600 cm-1区间的分析.通过与常规的傅里叶去卷积谱及差谱方法相比,本方法可消除样品浓度所带来的影响因素,灵敏地揭示群体数据中组分与结构在不同组间的显著差异,如1638 cm-1处重叠的蛋白二级结构峰,1172 cm-1、1440 cm-1表征脂类物质的吸收峰,1064 cm-1表征磷酸化合物峰位及表征SH的2553 cm-1附近的吸收峰在正常组与地中海贫血组间存在显著差异.从而避免了几个峰位的相对强度所反映的信息不足及选择参比峰的困扰,对揭示整体的差异变化规律有着重要的作用.     

一种脂溶性异黄酮化合物的晶体结构及抗氧化活性研究

本文合成了5-甲基-7-羟基-4-甲氧基异黄酮,采用IR,UV,1H NMR,和元素分析对其结构进行了表征,并利用X射线单晶衍射仪测定了该化合物的晶体结构。用紫外光谱法研究了它们对超氧阴离子自由基和1,1-二苯基-2-苦肼基自由基(1,1-diphenyl-2-picrylhydrazyl free radical简称DPPH.)的清除活性.实验结果表明5-甲基-7-羟基-4′-甲氧基异黄酮化合物(C17H14O4)属于三斜晶系,空间群为P1。a=0.82255(2)nm,b=0.93123(2)nm,c=1.04547(2)nm,α=89.0432(2)°,β=69.1950(10)°,γ=66.9790(10)°,Z=2,V=0.681 99(3)nm3,Dc=1.375 g.cm-3,F(000)=296,R1=0.044 4,wR2=0.115 6,而且该化合物具有较好的清除羟基自由基和超氧自由基的作用。     

Variational iteration method for solving the multi-pantograph delay equation

In this Letter, the variational iteration method is applied to solve the multi-pantograph delay equation. Sufficient conditions are given to assure the convergence of the method. Examples show that the method is effective.