Synthesis and structural characterization of a new molecule-based complex constructed from dodecamolybdophosphoric acid and imidazole

A new compound, (CH5N2)(3)(PMo12O40CH4N23H2O)-C-.-H-. (1), was synthesized and structurally characterized by elemental analyses, IR spectra, UV spectra, NMR spectra and ESR spectra. This is, to our knowledge, the first example of an imidazole-polyoxometalate species. The compound was recrystallized from N,N-dimethylformamide (DMF), and then black block-like crystals of (C3H5N2)(4)((PMoMo11O40)-Mo-V-O-VI)(.)4C(3)H(7)NO(.) 2H(2)O (2), were obtained. It crystallizes in a triclinic space group P (1) over bar with n=12.423(3) Angstrom, b=12.666(3) Angstrom, c=13.341(3) Angstrom, alpha=70.56(3)degrees, beta=71.16(3)degrees, gamma=64.18(3)degrees, V= 1742.3(6) Angstrom(3), Z=1, R1 = 0.0585, wR2 = 0.1885. An X-ray crystallographic study showed that the crystal structure is constructed by electrostatic attractions and hydrogen bonds between a dodecamolybdophosphoric anion and an imidazole. The imidazole and DMF molecules occupy cavities in a polyoxometalate lattice ordered along a c-axis. The structure of (2) is similar to that of (1) from a comparison of both IR spectra and TGA Curves.

一种新型防护装甲干扰射流的工程算法

在研究干扰射流机理的基础上 ,从工程角度提出了一种新型防护装甲干扰射流的力学模型。并在基本假设的基础上 ,对射流击中装甲单元后在介质中产生的冲击波进行了压力估算 ,及装甲单元的壁板变形和射流变形的计算。计算结果与试验结果基本吻合。

Studies on the method of leaps and bounds regression

In this paper, we introduce the method of leaps and bounds regression which can be used to select variables quickly and obtain the best regression models. These models contain one variable, two variables, three variables and so on. The results obtained by using leaps and bounds regression were compared with those achieved by using stepwise regression to lead to the conclusion that leaps and bounds regression is an effective method.

Thermal, mechanical and ionic conductive behaviour of gamma-radiation induced PEO/PVDF(SIN)-LiClO4 polymer electrolyte system

An effort has been made to modify the mechanical behaviour of our previously reported gel-type gamma-radiation crosslinked polyethylene oxide (PEO)-LiClO4 polymer electrolyte. A highly polar and gamma-radiation crosslinkable crystalline polymer, polyvinylidene fluoride (PVDF), was selected to blend with PEO and then subjected to gamma-irradiation in order to make an simultaneous interpenetrating network (SIN), which was used as a polymer host to impart stiffness to the plasticized system. Experimental results have shown that the presence of PVDF in the system, through gamma-radiation induced SIN formation, could not only give a rather high mechanical modulus of 10(7) Pa at ambient temperature, but also maintain the room temperature ionic conductivity at a high level (greater than 10(-4) S/cm). DSC, DMA and conductivity measurement techniques were used to examine the effects of blending, gamma-irradiation and plasticization on the variations of glass transition and melting endotherm, on the appearance of high elastic plateau and on the temperature dependence of ionic conductivity: In addition, it was found that, in contrast with the unplasticized system, the ionic conductivity mechanism of this gel-type electrolyte seems to conform to the Arrhenius model, suggesting that, as a result of the high degree of plasticization, the polymer chains act mainly as the skeleton of the networks or polymer cages to immobilize the liquid electrolyte solution, whereas the ionic species migrate as if they were in a liquid medium. (C) 1997 Elsevier Science Ltd.

Tm_2O_3超微粉末的制备与性质

以乙醇为分散剂和保护剂，用沉淀法制备了Ｔｍ（ＯＨ）_３、Ｔｉｎ_２Ｏ_３超微粉末．ＸＲＤ分析表明，Ｔｍ（ＯＨ）_３为无定形；不同温度焙烧所得到的Ｔｍ_２Ｏ_３均为立方晶系，空间群为Ｔ５－１２１３．计算表明，随焙烧温度的升高，Ｔｍ_２Ｏ_３晶粒增大，平均晶格畸变率减小．ＴＥＭ分析表明，超微粒子呈球形．在酸中溶解性试验表明，Ｔｍ_２Ｏ_３粒子越小，溶解百分率越大．红外光谱分析表明，超微Ｔｍ_２Ｏ_３比多晶Ｔｍ_２Ｏ_３具有更高的表面活性，Ｔｍ－Ｏ键的吸收具有微小的蓝移，吸收强度减弱．

药物分子在玻碳电极上的电分析化学研究——Ⅲ.柱晶白霉素的伏安测定

本文对柱晶白霉素在GCE上的伏安行为进行了研究,发现在磷酸盐缓冲溶液(pH7.13)于+0.93V(vs.Ag/AgCl)左右产生一清晰伏安氧化峰可用于定量,分析了制剂中柱晶白霉素的含量,得到满意的结果,经循环伏安法验证,柱晶白霉素在GCE上的电极反应为不可逆反应.

STUDIES OF SPINEL LICRXMN2-XO4 FOR SECONDARY LITHIUM BATTERY

X-ray and electrochemical studies of spinel-related manganese chromium oxides, LiCrxMn2-xO4 (0 less-than-or-equal-to x less-than-or-equal-to 1) were carried out in a lithium nonaqueous cell. X-ray diffraction spectra indicated that the substitution of manganese in LiMn2O4 by trivalent transition metals (Cr3+) cause the linear decrease of lattice parameter with the x in the LiCrMn2-xO4. Some discharge-capacity loss was obtained due to the lattice contraction of LiCrMn2-xO4, but it has a better rechargeability than LiMn2O4. Cyclic voltammetry and electrochemical impedance experiments have shown that the excellent rechargeability of LiCrxMn2-xO4 may be attributed to the good reversibility of the change in its crystal structure for the insertion and extraction of lithium ions.

钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯-Triton X-100体系的析相富集及痕量钴的光度测定

本文研究了TritonX-100在浊点条件下对钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯(5-Cl-PADAB)络合物的析相条件,在pH4.0～6.0介质中,将胶束溶液加热到92±1℃,保持40min,络合物即被TritonX-100相富集。富集液在575nm测定吸光度,钴含量在0～4μg/5ml范围内服从比尔定律,干扰离子可在TritonX-100析相液中加入H_2SO_4消除。拟定的方法灵敏、简捷,已用于不经分离直接测定人发及自来水中痕量钴。

DOPING EFFECTS ON THE POLYMER-CHAIN STRUCTURE OF POLY(3-METHYLTHIOPHENE)

The C=C stretching Raman shifts and photoluminescence (PL) for poly(3-methylthiophene) (P3MT) are measured at various doping levels by in situ electrochemical Raman and PL spectroscopic techniques. It is found that the doping for P3MT induces the nonlinear excitations (soliton, Polaron, bipolaron), but also affects the polymer-chain structure, including the conjugated length and the interchain distance.

几种溴化改性聚烯烃的富氧性能

研究了聚(4-甲基戊烯-1)、有规及无规聚丙烯的溴化反应。反应以自由基机理进行,溴取代主要发生在主链上的叔氢原子上。溴化反应改变了三种聚合物的溶解和物理性能。溴化产物的透氧系数 P_(v_2)下降,分离系数α_(O(?)N)有所提高,有可能满足某些特殊气体分离膜的要求。

杂多酸催化性能的研究——Ⅱ.12-钼和12-钨杂多酸催化烯烃环氧化物与苯甲醇的醚化

研究了12-钼和12-钨磷酸在环氧乙烷和环氧(?)烷与苯甲醇的醚化反应中的催化作用。考查了反应条件对杂多酸催化活性的影响。实验结果表明,除了杂多酸中的质子在该反应中起着必要的作用外,杂多阴离子也有重要的催化作用。

Large-scale isolation and purification of R-phycoerythrin from red alga Palmaria palmata using the expanded bed adsorption method

R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.

Cloning and expression analysis of myogenin from flounder (Paralichthys olivaceus) and promoter analysis of muscle-specific expression

Myogenin is a bHLH transcription factor of the MyoD family. It plays a crucial role in myoblast differentiation and maturation. We report here the isolation of flounder myogenin gene and the characterization of its expression patterns. Sequence analysis indicated that flounder myogenin shared a similar structure and the conserved bHLH domain with other vertebrate myogenin genes. Flounder myogenin gene contains 3 exons and 2 introns. Sequence alignment and phylogenetic showed that flounder myogenin was more homologous with halibut (Hippoglossus hippoglossus) myogenin and striped bass (Morone saxatilis) myogenin. Whole-mount embryo in situ hybridization revealed that flounder myogenin was first detected in the medial region of somites that give rise to slow muscles, and expanded later to the lateral region of the somite that become fast muscles. The levels of myogenin transcripts dropped significantly in matured somites at the trunk region. Its expression could only be detected in the caudal somites, which was consistent with the timing of somite maturation. Transient expression analysis showed that the 546 bp flounder myogenin promoter was sufficient to direct muscle-specific GFP expression in zebrafish embryos. (c) 2007 Elsevier Inc. All rights reserved.