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181.
液晶电视由于其优异的显示性能将会越来越受到青睐。本文简要综述了近年来电视用液晶材料的研究进展,归纳总结了这些液晶材料的合成方法及其热性能、介电各向异性、双折射率、粘度等特性。 相似文献
182.
本标准物质系合金钢。主要成份有碳、硅、锰、磷、硫、铬、镍、钼、钒,同时还含有锡、铅、砷、锑、铋等微量元素,每种元素成份都具有良好的线性关系。它可作为量值传递和仲裁分析的依据,同时也可用于校验分析仪器与分析方法的正确性和可靠性。 相似文献
183.
荧光钙探针试剂及其在生物分析中的应用 总被引:2,自引:0,他引:2
本文评论了荧光钙探针试剂合成、性质、结构和生物分析应用方面的进展。各种典型的荧光钙探针试剂均已分别加以讨论。 相似文献
184.
A comparative quantum-chemical analysis of the electronic structures and spectroscopic parameters of the cycloalkanes C3H6, C4H8, C5H10, and C6H12 and their silicon analogs Si3H6, Si4H8, Si5H10 and Si6H12 was performed in the framework of the SCF MO LCAO method in the INDO approximation. Qualitative interpretation of “abnormal”
ionization potentials and energies of electronic absorption spectra of cyclopolysilanes has been given.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1105–1108, June, 1997. 相似文献
185.
K. Grob 《Journal of separation science》1978,1(5):263-267
During one year continuous use of on-column injection, the typical advantages described in our first report have fully been confirmed. In addition the analysis of large sample volumes has proved promising. Only minor modifications have been applied to the on-column injector device. Broad evidence has been gathered showing that full separation efficiency of the capillary columns after on-column injection is attained only when cold trapping or the solvent effect, as band shortening mechanisms, are working- While, under the conditions of on-column injection, cold trapping is less efficient than with other injection techniques, the opposite holds true for the solvent effect. Compared with splitless injection, the danger of excessive solvent condensation on the column is increased. A working rule is presented for establishing the optimal chromatographic conditions for handling large sample volumes while ensuring full separation efficiency yet avoiding harm to the column. 相似文献
186.
A.S. Berenblyum A.P. Aeeva L.I. Lakhman I.I. Moiseev 《Journal of organometallic chemistry》1982,234(2):237-248
[(PPh3)3(PPh2)2Pd3Cl] Cl, benzene and aniline hydrochloride were isolated as products of the reactions of (PPh3)2PdCl2]2 or [(PPh3)PdCl2]2 with H2 in organic amines (Am). Similar products were obtained when (Ph3P)2Pd(Ph)Br was treated with H23 Both in amines and aromatic solvents. The reaction between H2 and [(PBu3)PdCl2]2 resulted in the formation of [(PBu3(PBu2)PdCl2 ·. 2 Am The kinetic data for H2 absorption by solutions of palladium(II) complexes are consistent with the heterolytic mechanism of cleavage fo hte HH bond in the coordination sphere of palladium(II); the function of the H+ acceptor being performed by the bases (e.g. Am or Ph). The reaction between the palladium complexes and H2 is autocatalytic. Reduction of the initial PdII complexes leads to lower oxidation state palladium complexes, which catalyse the reduction of PdII complexes. In the coordination sphere of the lower oxidation state palladium complexes, the oxidative addition of PR3 to Pd takes place with formation of compounds containing a Pd-R bond. It is the reaction between these complexes and H2 that yields palladium compounds with PR2 ligands. 相似文献
187.
K. Jinno 《Journal of separation science》1982,5(7):364-367
The chromatographic performance of the deuterated solvents, CD3OD and D2O, has been investigated in reversed-phase micro high performance liquid chromatography. The chromatographic performance of CD3OD is only slightly superior to that of CH3OH. However, the performance of D2 is significantly superior to that of H2O, separation of aromatics being improved by about 30%. D2 is a particularly powerful solvent for the separation iof deuterated and non-deuterated compounds. 相似文献
188.
Gary W. Schnuelle S. Swaminathan David L. Beveridge 《Theoretical chemistry accounts》1978,48(1):17-27
A theoretical study of ion hydration using the statistical thermodynamic supermolecule-continuum method is described. The cell and shell methods are used for configurational averaging. Enthalpies, free energies and entropies are calculated for Li+, Na+, K+, F– and Cl– each four coordinated with water. The results are in reasonable accord with experiment. A comparison of the site method, cell method and shell method results is presented. The supermolecule-continuum approach to solvent effects seems to be capable of accommodating essential features for the calculation of solvation energy and solvent effects on structure and properties. 相似文献
189.
W. Pyckhout P. Van Nuffel C. Van Alsenoy L. Van Den Enden H. J. Geise 《Journal of Molecular Structure》1983,102(3-4):333-345
The gas phase molecular structure of methyl vinyl ether at room temperature has been studied by joint analysis of electron diffraction and microwave data. Constraints on geometrical and thermal parameters were derived from the geometry and force field of the s-cis form, obtained by ab-initio calculations (4–21 G basis set) after complete geometry relaxation. A range of models was investigated that fits all available data (infrared, microwave and electron diffraction). The following rg/r-parameters were obtained: C=C: 1.337 Å, C(sp2)---O: 1.359 Å, C(sp3)---O: 1.427 Å, : 1.102 Å C=C---O : 127.3° and COC: 116.8°. Experimental rg---re (ab initio) corrections are given for C=C, C(sp2)---O and Csp3)---O.
This investigation demonstrates that molecular orbital constrained electron diffraction is sufficiently reliable and in such a manner that it can be applied to more complicated problems. 相似文献
190.
Marie-Paule Pileni 《Chemical physics letters》1980,75(3):540-544
Photoinduced electron transfer from Zn tetraphenylporphyrin to acceptors solubilized either in the lipid interior or aqueous bulk of anionic oil-in-water microemulsions has been investigated by nanosecond laser photolysis. While intimate cosolubilization appears to decrease the efficiency of electron transfer in the former, enhanced charge separation of the redox products has been observed in the latter. 相似文献