375 resultados para Bibel, Levitikus, 13,2-46


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Selective crystallization of BaF2 crystals under a compressed Langmuir monolayer of behenic acid [CH3(CH2)(20)COOH] has been studied by using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analysis. It was found that, in the absence of a monolayer, three kinds of crystals (Ba2ClF3, BaClF, and BaF2) can be obtained by mixing BaCl2 with a NH4F solution. However, in the presence of the monolayer of behenic acid, only BaF2 crystals appear at the monolayer-subphase interface and crystals have a special crystal face (100). During this process of crystallization, the monolayer plays a very important role and acts as a template that can preferentially select a special crystal and a special crystal face. The above results can be explained in terms of a specific molecular interaction between ions and the headgroups of the monolayer and specific electrostatic, geometric, and stereochemical interactions at the organic-inorganic interface.

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本文综述了纳米发光材料的研究进展情况 ,着重总结了 (稀土 )掺杂型纳米发光材料的制备方法和表征手段 ,同时介绍了这些纳米发光材料的性质和应用 ,并对其未来发展趋势进行了展望。

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采用动态力学和数学拟合相结合的方法 ,研究了聚环氧乙烷环氧丙烷—LiClO4 体系的离子解离与缔合。结果表明 :Tg的增加依赖于盐浓度和环氧乙烷 (EO)与环氧丙烷 (PO)的比例 ,并且玻璃化转变温度 (Tg)的增加可以用一个简单的溶解平衡解释 ,进而得出平衡常数K和离解度α

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CeO2 nanometer powders of different sizes were prepared at low temperature by pyrolysis of amorphous citrate. XRD patterns show that CeO2 is cubic in structure, space group O-h(5)-F-M3M. TEM indicates that the prepared CeO2 is spherical in shape, and the particle size distribution is in narrow range. It was found that calcination temperature is a more important factor affecting the crystallite size of CeO2 than calcining time, the smaller the particle, the bigger the crystal lattice distortion, the worse the crystal growth. Solubility test of CeO2 in nitric acid reveals that the surface activity of CeO2 decreases with the increasing particle sizes. IR spectra analysis shows that the absorption of Ce-O bond is shifted to higher energy with the decrease of CeO2 particle sizes.

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通过引入成核剂(Nd2O3)研究PA1010微晶结构的变化,以及对PA1010结晶行为的影响,也讨论了成核剂对结晶-非晶中间相的作用。利用WAXD,SAXS和DSC手段,讨论了成核剂的异相成核作用。结果表明,成核剂明显改变了PA1010的微晶结构。

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采用锥板流变仪研究了本实验室合成的含对羟基苯甲酸、对苯二甲酸、间苯二酚、4,4′-二羟二苯酮共聚酯的流变行为,结果表明,该共聚物具有典型的热致液晶性聚合物的流变特性。

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在二甲亚砜水混合溶剂中用pH电位法测定了T4的质子化常数以及与五种希土离子(Pr3+、Eu3+、Gd3+、Tb3+、Yb3+)生成配合物的稳定常数。体系中主要生成110型配合物,紫外吸收光谱,HNMR表明,在较低pH值,T4通过羧基与希土配位,pH较高时,氨基也相继配位。配位键以离子性为主,荧光光谱表明,T4对中心希土离子的荧光有猝灭作用。

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The structural parameters of the aggregated state in the polyamide PA1010 and N,N'-bismaleimide-4,4'-diphenyl methane (BMI) system were computed by means of the desmearing intensity from SAXS and using the concept of the distance distribution function. The results revealed that the parameters Q, I(0), l(c) and L decreased with the increase BMI component, whereas O-s increased. The particle dimension Z for different BMI contents was less than 13.2 nm, and the maximum value of the distance distribution function P(Z) was found to be in the range Z = 6.5-7.0 nm.

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合成了HPW12、HSiW12杂多酸的一系列铯盐:CsxH3-xPW12(x=0~3),CsxH4-xSiW12(x=0~4).测定了它们的酸强度、pH滴定曲线、NH3-TPD、IR光谱和比表面积.以乙酸和正丁醇的酯化为探针反应,考察了催化剂的酸催化活性.实验发现,碱金属取代后,PW12系列的多数催化剂的酸强度提高,而SiW12系列的则降低,但对同一系列来说,由NH3-TPD测得的酸强度和酸量均随取代量增加而减小,pH滴定的结果与此类似,当x=2.5时,两系列催化剂的比表面积均存在一个极值.对乙酸和正丁醇的催化酯化活性只与总酸量有关,与表面积无关,属假液相反应.

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不同联苯含量的PEEKK-PEBEKK共聚物的DSC结果表明,随着联苯含量的增加,共聚物的玻璃化转变温度几逐渐升高;共聚物的熔点Tm明显地依赖于联苯含量,当联苯含量nB=0.35时,Tm值最4小。热处理可以显著地改善共聚物的结晶性,并出现熔融重结晶双峰。

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含4,4'-二羟基二苯酮热致液晶四元共聚酯的合成与表征董德文,韩平,倪玉山,丁孟贤,韩伟(中国科学院长春应用化学研究所长春130022)(吉林化工学院化工系吉林)关键词 热致液晶,共聚酯,向列型,二羟基二苯酮关于热致液晶芳香族聚酯的研究已有大量的报道...

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钼钒酸铋体系催化剂上丙烷的选择氧化反应李静,宋伟,窦伯生(中国科学院长春应用化学研究所长春130022)关键词丙烷,选择氧化,钼钒酸铋,助剂,丙烯醛合理利用天然气及石油裂解气为人们所关注。由于烷烃较相应烯烃反应活性低,使其在工业上的应用远不及烯烃,相...

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光固化聚酯丙烯酸氨基甲酸酯树脂的合成及其性质黄景琴,田禾,孝延文,杨振华,陈文启(中国科学院长春应用化学研究所长春130022)关键词 光固化树脂,齐聚物,丙烯酸氨基甲酸酯,合成为了降低污染和减少能耗,非溶剂型树脂被广泛地用作涂料、粘接剂、绝缘材料等...

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多组分氧化物Ag-Bi-V-Mo-O催化作用的光电子能谱研究宋伟,李静,窦伯生(中国科学院长春应用化学研究所长春130022)关键词 钼钒酸铋,助剂Ag,XPS,Ar~+刻蚀,氧化还原对于烃类选择氧化反应中复合氧化物的催化作用,普遍认为是Redox机...

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掺杂元素的Lewis酸强度对掺杂In_2O_3电性质的影响文世杰G.Campet(LawrenceBerkeleyLaboratory,BerkeleyCA94720,USA)(LaboratoiredeChemieduSolideduCNRS,Uni...