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91.
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
92.
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
93.
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
94.
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
95.
用X-射线荧光光谱法,测定了387例内蒙古牧区蒙古族、汉族成人和儿童的发中铜(Cu)、锌(Zn)、铁(Fe)、锶(St)及钙(Ca)的含量,对同一地区蒙、汉族成人间,成人及儿童间发中五种元素含量进行了比较分析。结果表明:蒙汉族成人发中Cu,Zn、Fe含量不受种族及饮食习惯的影响,其含量无显著性差异;蒙汉族成人发中Sr和Ca含量存在着相平行的显著差异;牧区儿童发Zn含量与牧区成人发Zn含量差异无显著性意义,提示牧区儿童不缺Zn,可能与多动物性食物有关;牧区儿童发中Cu、Fe、Sr、Ca均显著低于牧区成人、可能与儿童发育旺盛和Zn摄入量高对Cu、Fe吸收发生抑制有关。 相似文献
96.
The molecular and electronic structure of the ground state of peroxyacetyl nitrate (PAN) was calculated by the unrestricted
Hartree-Fock-Roothaan method with the use of the standard 3–21G and 6–31G basis set. The potential curve of the internal rotation
about the peroxide bond of PAN was calculated with the 6–31G basis set. The curve contains two maxima. The ground state of
PAN is characterized by a structure in which groups of atoms adjacent to the peroxide bond lie in planes that are perpendicular
to each other (the dihedral angle ϱ(COON) is 89.9°). The calculated barriers to rotation are 19.6 and 66.8 kJ mol−1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 600–604, April, 1998. 相似文献
97.
《Mendeleev Communications》2020,30(4):482-484
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98.
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
99.
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
100.
Franz Andreas Mautner Harald Krischner Christoph Kratky 《Monatshefte für Chemie / Chemical Monthly》1988,119(11):1245-1249
[N(CH3)4]Ca(N3)3,M=240.29, was prepared from aqueous solutions of tetramethylammoniumazide with calciumazide at 298 K. The crystals are tetragonala=936.6(7) pm,c=694.7(5)pm, space group P4/nmm,Z=2, (x)=1.31Mgm–3. The crystal structure was determined by single crystal x-ray diffraction (234 Mo-K-reflections, =0.469 mm–1,R=0.064). Calcium is octahedrally coordinated to six azide groups. The octahedra are connected via azide groups to a threedimensional array with the complex ammonium ions between. The terminal nitrogen atoms of the azide groups and the methyl groups are considerably disordered. 相似文献