124 resultados para 357-M0075B


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合成了一系列结构为层状ABO3的复合氧化物La4BaCu5-xMxO13(M=Mn,Co),并利用XRD、X射线能谱、氧程序升温脱附和化学分析方法对它们的结构和活性氧种进行了研究。XRD分析结果表明:它们的结构为五层的ABO3结构。活性氧种的研究表明La4BaCu5O13中掺杂Mn或Co之后,样品中明显存在的MCu(M=Mn,Co)之间的协同作用,并且CuMn之间协同作用明显比CuCo的强。

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The crystallization and melting behaviours of a multiblock copolymer comprising poly(ether ether ketone) (PEEK) and poly(ether sulfone) (PES) blocks whose number average molecular weights <((M)over bar (n)'s)> were 10 000 and 2900, respectively, were studied. The effect of thermal history on crystallization was investigated by wide-angle X-ray diffraction measurement. A differential scanning calorimeter was used to detect the thermal transitions and to monitor the energy evolved during the isothermal crystallization process from the melt. The results suggest that the crystallization of the copolymer becomes more difficult as compared with that of pure PEEK. The equilibrium melting point of the copolymer was found to be 357 degrees C, about 30 degrees C lower than that of pure PEEK. During the isothermal crystallization, relative crystallinity increased with crystallization time, following an Avrami equation with exponent n approximate to 2. The fold surface free energy for the copolymer crystallized from the melt was calculated to be 73 erg cm(-2), about 24 erg cm(-2) higher than that of pure PEEK. Copyright (C) 1996 Elsevier Science Ltd.

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本文第一部分电化学,1986,2(3)回顾了DEMS方法原理和发展,这里继续介绍DEMS方法的一些应用结果,如CH3OH,HCOOH,CO,CO2,NO2-,NO3-以及一些不饱和碳氢化合物的电化学氧化或还原研究.

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利用预辐照接枝法合成了聚乙烯醇双胺肟螯合纤维。研究了影响接枝率和胺肟基团含量的因素,讨论了吸附酸度、吸附时间对Cu(Ⅱ)离子吸附容量的影响。合成的聚乙烯醇双胺肟螯合纤维对Cu(Ⅱ)离子的吸附容量达1.62mmol/g干纤维,在5min内达到吸附平衡。

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Eight heteropoly blues of bis-2:17 molybdophosphate complexes with Lathanide, i.e., K17H2[Ln(P2Mo17O61)2] . nH2O and K17H4[Ln(P2Mo17O61)2] . nH2O were synthesized and characterized by elemental analyses potentiometric titration, IR, UV, polarography, cyclic voltammetry, X-ray photoelectron spectra X-ray powder diffraction, thermal analyses and ESR. Experimental results show that the properties of these series of heteropoly blues are different from those of their oxidized form, but no great changes in their structures were observed. The ligand P2Mo17O6110- remains alpha2-isomer's configuration.

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提出了由β,β-1,3-亚丙二硫基-α,β-不饱和芳酮类化合物(1)与苄基氯化镁及烯丙基溴化镁加成所得的醇(2)在BF_3·Et_2O催化下脱水生成共轭烯烃(3)新的合成途径,合成了13种新化合物,结构经~1H N-MR、IR、UV及元素分析等确证.并对这一新合成途径的反应机制进行了讨论.

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首次合成和离析了八种以缺位型Dawson结构钼磷杂多阴离子为配体的稀土杂多蓝K_(17)H_2[Ln-(P_2Mo_(17)O_(61))_2]·nH_2O和K_(17)H_4[Ln(P_2Mo_(17)O_(61))_2]·nH_2O(Ln=La,Pr,Sm,Yb).通过元素分析、电位滴定、红外光谱、紫外光谱、极谱、循环伏安、X射线光电子能谱、热重-差热分析和电子顺磁共振对杂多蓝进行了表征.实验结果表明,杂多阴离子还原为杂多蓝后,性质发生了某些变化,但结构基本不变,配体P_2Mo_(17)O_(61)~(10-)仍为a_2型.

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K7H6[Nd(GeMo11O39)2].18H2O was first synthesized and the crystal structure was determined. Crystal structure data are as follows: monolinic, space group P2(1)/n, a = 1.7095(4), b = 2.6895(3), c = 2.1214(5) nm, beta = 103.11 (2)-degrees, V = 9.4994(3) nm3, Z = 4, D(m) = 3.14g/cm3, D(c) = 3.05g/cm3, mu(MoK-alpha) = 43.7 cm-1. Experimental evidence and theoretical foundation of the method inferring the molecule structure of heteropoly compounds using their IR spectra were gaved by studying IR spectra properties of the complex with results of structural analysis. Electronic spectra prove that 4f-obital of Nd3+ take part in bonding in the complex.

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合成及制备了K_7H_6[Nd(GeMo_(11)O_(39))_2]·27H_2O单晶,测定其晶体结构,空间群属P2_1/n,晶胞参数:α=1.7095(4),b=2.6895(3),c=2.1214(5)nm,β=103.11(2)°;V=9.4994(3)nm~3;Z=4;D_m=3.14g/cm~3,D_c=3.05g/cm~3;μ(MoKα)=43.70cm~(-1)。利用结构分析的结果,研究配合物的IR光谱性质,提出利用IR光谱推测杂多配合物分子结构特征的实验证据和理论根据。电子光谱证实配合物中Nd~(3+)的f轨道参与成键。

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聚偏氟乙烯(PVF_2)是一种半结晶聚合物,它至少存在α、β、γ和δ四种晶相结构。其中β相由于其与PVF_2的压电性和热电性直接相关而引起人们的广泛关注。在以前的工作中,我们研究了超速淬火对PVP_2晶相结构的影响。本工作用傅里叶变换红外光谱(FTIR)技术研究了聚甲基丙烯酸甲酯(PMMA)分子构型对淬火过程中PVF_2β相生成温度的影响.

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赤血盐〔K_3Fe(CN)_6〕是化学、医药、造纸、彩色胶卷等许多工业中经常使用的重要化学试剂和化工原料,在电镀、制革及钢铁工业中的应用更具有悠久历史。目前在选矿及其它领域也找到了一些新的用途。过去生产 K_3Fe(CN)_6均采用化学氧化法,使用氧化剂有 Cl_2、KMnO_4、O_3等。自本世纪60年代以来,欧洲一些厂家相继改

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Calcareous algae such as Corallina pilulifera a Postels et Ruprecht can be one of the most potential candidates to be used in biological carbon dioxide assimilation to reduce greenhouse effect because of its calcification capacity as well as photosynthesis if utilized extensively and properly. The major elemental composition in C. pilulifera is as follows: sodium 0.13%, chloride 1.75%, magnesium 4.37%, calcium 18.4%, iron 0.31%, and carbonate 28.5%. Calcareous algae can be used as elemental provider for livestock or agriculture. (C) 1999 Elsevier Science Ltd. All rights reserved.

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Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate (SGR) of 10.47 at 25A degrees C/40 mu mol m(-2)s(-1). Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 mu m in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues.

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N-Acetylchitooligosaccharide (N-acetyl-COs) was prepared by N-acetylation of chitooligosaccharide (COs). In vitro study using human umbilical vein endothelial cells (HUVECs) revealed that both N-acetyl-COs and COs inhibited the proliferation of HUVECs by inducing apoptosis. Treatment of HUVECs by N-acetyl-COs resulted in a significant reduction of density of the migration cells and repressed tubulogenesis process. The antiangiogenic effects of the oligosaccharides were further evaluated using in vivo zebrafish angiogenesis model, and the results showed that both oligosaccharides inhibited the growth of subintestinal vessels (SIV) of zebrafish embryos in a dose-dependent manner, as observed by endogenous alkaline phosphatase (EAP) staining assay. In contrast, no cytotoxicity was found when treating the NIH3T3 and several other cancer cells with the oligosaccharides. Our results also confirmed the antiangiogenic activity of N-acetyl-COs was significantly stronger than the parent oligosaccharide, COs. (c) 2007 Published by Elsevier Inc.