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91.
The CGC analysis of 25 organophosphorus and organonitrogen pesticides was optimized on two different stationary phases, namely a 5% diphenyl dimethyl silicone (SE-54 type) and a 50% diphenyl dimethyl silicone (OV-17 type) by selecting the best temperature program conditions, using computer simulation. 相似文献
92.
The effect of the superposition of electroosmotic flow and pressureinduced hydrodynamic counterflow on efficiency has been investigated for different capillary electrophoretic systems. Results are shown for 50 and 75 μm internal diameter capillaries at several voltage and counterpressure levels. Hydrodynamic counterflows were successfully applied in electrokinetic chromatography in order to delay the entry of a UV-active pseudostationary phase, tetraphenyl porphyrintetrasulfonate, into the detection zone allowing the separation of neutral nitroaromatics. The separations are based on the weak charge-transfer interactions between the porphyrin and the analytes. 相似文献
93.
Arsenidostannates with [SnAs] Nets Isostructural to Grey Arsenic: Synthesis and Crystal Structure of Na[Sn2As2], Na0.3Ca0.7[Sn2As2], Na0.4Sr0.6[Sn2As2], Na0.6Ba0.4[Sn2As2], and K0.3Sr0.7[Sn2As2] The metallic lustrous compounds Na[Sn2As2], Na0.3Ca0.7[Sn2As2], Na0.4Sr0.6[Sn2As2], Na0.6Ba0.4[Sn2As2] and K0.3Sr0.7[Sn2As2] were prepared from melts of mixtures of the elements. The compounds crystallize in the trigonal system (space group R3 m, No. 166, Z = 3) with lattice constants see in “Inhaltsübersicht”. The structures are isotypic to Sr[Sn2As2] containing puckered [SnAs] nets which are stacked with a sequence of six layers. The E(I)/E(II) atoms are located between each second [SnAs] layer in trigonal antiprismatic interstices formed by As atoms. In the resulting [Sn2As2] double layers the ∞2[SnAs] nets are stacked in such a way that additional Sn—Sn contacts arise. 相似文献
94.
95.
Laref A 《Journal of computational chemistry》2012,33(1):1-10
We investigate the structural, electronic and dynamical properties of ZnSe liquid using tight-binding molecular dynamics (TBMD) simulations. We report the TBMD calculations for the solid and liquid forms of the ZnSe compound. To produce more realistic results the TB model includes the local environment dependence in the Hamiltonian matrix at finite temperature for ZnSe. To further demonstrate the efficiency of the TBMD approach, we present results for finite temperature physical properties of ZnSe liquid. We are able to show good agreement with experiment for the atomic mean-squared displacement and melting point. 相似文献
96.
97.
Françoise Maugé Jean-Paul Gallas Jean-Claude Lavalley Guido Busca Gianguido Ramis Vincenzo Lorenzelli 《Mikrochimica acta》1988,95(1-6):57-61
In the far IR region at low molybdenum loadings, Mo-SiO2 catalysts present a pseudomolybdate or a polymolybdate species, while bulk-like MoO3 appears at loadings close to the geometrical monolayer coverage. W-SiO2 and V-SiO2 spectra show bands close to those observed on the corresponding bulk oxides.In the case of TiO2, Al2O3, ZrO2 supported catalysts, a band is observed near 1000 cm–1 which is assigned to the Mo=O stretching vibration of coordinatively unsaturated Mo
n+ ions showing a stronger interaction with the support than one observed on silica. 相似文献
98.
Due to their high polarity and unique selectivity, cyanopropyl silicones are basic stationary phases for high resolution capillary gas chromatography. Different OH-terminated cyanopropyl silicones, containing a high cyanopropyl content, were synthesized and chromatographically evaluated. Special attention was paid to the degree of immobilization of the phases in FSOT columns. Depending on the problem at hand, a choice has to be made between immobilization and maximum selectivity. 相似文献
99.