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221.
222.
选择不同电离电位的基体元素K、Na、La、Y和Mg,比较研究了它们对分析元素谱线强度的影响,其影响程度与谱线激发电位及基体元素电离电位有定量的相关关系。碱金属基体(K、Na)和非碱金属基体(La、Y和Mg)对分析元素检出限、背景强度及其相对标准偏差的影响显著不同,后者的记忆效应也大于前者。La的电离电位与Na相差不大。但其基体效应与Y相似,表明墓体效应与基体元素的化学性质有关。 相似文献
223.
A series of benzylideneanilines bearing terminal polyether chains, HL (HL = R-C6H4-CHN-C6H4-R′: R = OC8H17, R′ = O(CH2CH2O)2C2H5; R = O(CH2CH2O)2C2H5, R′ = OC8H17; R = R′ = O(CH2CH2O)2C2H5; R = OC12H25, R′ = O(CH2CH2O)3C2H5; R = O(CH2CH2O)3C2H5, R′ = OC12H25; R = R′ = O(CH2CH2O)3C2H5) have been prepared. Their dinuclear, [Pd(μ-X)L]2 (X = OAc, Cl, Br, SC8), [Pd2(μ-SCn)(μ-X)L2] (X = OAc, Cl; n = 8, 2) and mononuclear orthopalladated derivatives, Pd(acac)L, Pd(Ala)L, are reported and their mesogenic properties are compared with those of the analogous compounds with alkoxy chains. In general a great lowering in the melting points is produced for all the products. The free ligands and the alanine complexes are not liquid crystals. The chloro-bridged complexes bearing alkoxy and short polyether chains (O(CH2CH2O)2C2H5) show the larger improvement of mesogenic properties. Longer polyether chains (O(CH2CH2O)3C2H5) result usually in a destabilization of the mesophases. If only polyether chains are present, the destabilization is important regardless of the chain length. The ability of these molecules as ionic extractants and transporters was qualitatively evaluated for the more propitious cis-dinuclear complexes, which in fact showed some extracting ability, modest but improved compared to the free ligands. 相似文献
224.
Enthalpies of solution have been measured from 5 to 85°C for aqueous tetraethyl- and tetrapropylammonium bromides, and the integral heat method is employed to evaluate
for these electrolytes over a wide temperature range. Data taken from the literature have been used to evaluate
for aqueous Bu4NBr over a similar temperature range. These data, along with similar data for Me4NBr, previously reported, have been used to evaluate absolute ionic heat capacities. While the absolute values agree only qualitatively with two other methods of division, the temperature dependences of the three methods essentially agree up to 65°C. Heat capacities due to structural effects on the solvent, obtained by subtracting the inherent heat capacities of the ions, are extraordinarily positive for all four tetraalkylammonium ions and have negative temperature coefficients, indicating that all four ions, including the tetramethylammonium ion, are structure-making ions. 相似文献
225.
The effect of CuO on the thermal behaviour of Zr/KClO4 primer mixtures was studied by thermoanalytical techniques, and the Bruceton method and its related calculation. It was found that the CuO catalytically promoted the decomposition of Zr/KClO4 primer mixtures and shifted the exothermic peak of DSC curves to lower temperatures. In addition, the Zr/KClO4 primer mixture containing CuO had a significant effect on the firing characteristics of electro-explosive devices. 相似文献
226.
水溶性聚酯的结构和性能 总被引:2,自引:0,他引:2
由对苯二甲酸二甲酯、间苯二甲酸、间苯二甲酸二甲酯5-磺酸钠与乙二醇等共缩聚合成的PET型水溶性聚酯(WSP)是一种新型的水溶性聚合物,在化纤、纺织、涂料、粘合剂、电子、油墨等领域有着广泛的应用前景.化纤领域超细纤维新材料的研究、开发和生产,迫切需要一... 相似文献
227.
228.
A. E. Raevskaya A. L. Stroyuk S. Ya. Kuchmii Yu. M. Azhnyuk V. M. Dzhagan M. Ya. Valakh 《Theoretical and Experimental Chemistry》2006,42(3):162-168
The optical characteristics of CdSe nanoparticles, produced in aqueous solutions and polymer films in the reaction of cadmium
chloride and sodium selenosulfate, were studied. The main parameters that make it possible to vary the forbidden band width
were identified. The absorption, photoluminescence, Raman, and nonstationary decolorization spectra of CdSe nanoparticles
of various sizes were analyzed. It was demonstrated that under the conditions of pulsed irradiation the CdSe nanoparticles
are capable of accumulating excess electrons and inducing redox transformations in components of the solution (oxygen, methylviologen,
and sulfite ions).
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 3, pp. 150–155, May–June, 2006. 相似文献
229.
本文研究了邻位取代苯基氯化汞o-XC_6H_4HgCl(X=CH_3、H、Cl、Br、COOC_2H_5、NO_2)与HCl(NaI)在85%对氧陆圜水溶液中的质子分解反应,证明反应按S_El历程进行。视取代基不同,反应速度次序如下:CH_3>H>Cl>COOC_2H_5~Br>NO_2。从化学反应与紫外光谱的研究以及理论计算结果表明,p或π电子的邻位取代基对水原子有分子内配位,它对反应速度有重要影响。测定了15种p-、m-、o-取代苯基氯化汞在80%对氧陆圜水溶液中在40.0℃的质子分解反应的速度常数k_1,表明给电性取代基加速反应,吸电性取代基使反应减慢,这可以看作是反应中心在芳环上的芳基汞化合物的S_E1反应所具有的一个特点。 相似文献
230.