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991.
A mathematical framework for translational Brownian motion on hypersurfaces is presented, using an imbedding of the surface and Ito diffusions in the ambient space. This includes a survey of Ito calculus and differential geometry. Computational methods for time correlation functions relevant to spin relaxation studies on curved interfaces are given, and explicit calculations of time correlation functions and order parameters for a Rippled surface are presented. 相似文献
992.
Choudary BM Chowdari NS Jyothi K Kumar NS Kantam ML 《Chemical communications (Cambridge, England)》2002,(6):586-587
A new bifunctional catalyst consisting of active palladium and osmium species anchored on silica gel through a mercaptopropyl spacer and a cinchona alkaloid respectively has been prepared for the first time and used in the heterogeneous tandem Heck-asymmetric dihydroxylation of olefins to afford diols with excellent yields and enantiomeric excesses (ee's) in presence of N-methylmorpholine N-oxide or K3Fe(CN)6 as cooxidants. 相似文献
993.
D. T. Asil'bekova S. D. Gusakova A. U. Umarov F. N. Suleimanova D. N. Alavutdinov 《Chemistry of Natural Compounds》1981,16(6):550-553
The presowing irradiation of cotton seeds with pulses of concentrated light (PCL) causes a change in a number of indices of the oil. When the seeds are stored, oxidative processes in them are intensified. In the oil of the harvested seeds some indices are restored.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent, and S. V. Starodubtsev Institute of Technical Physics of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 777–780, November–December, 1980. 相似文献
994.
Summary The structure of the heterobinuclear complex of Ni2+ and [U022]2+ with the tetraanionic ligand derived from the condensation of 1,2-diaminoethane with o-acetoacetylphenol has been determined from diffractometer data and refined to R = 7.2%. The crystals are monoclinic, P21 /a, with = 20.65(2), b = 8.58(1), c = 14.68(2) Å and = 97.78(5); Z = 4. The ligand employed has two different coordination sets of atoms, N2O2 and O2O2, two oxygen atoms being common to both donor sets. In the complex the nickel ion, which is four coordinate but not square planar, is retained in the inner N2O2 chamber, whilst the uranyl ion is incorporated in the outer O2O2 chamber. A molecule of solvent is retained to preserve the preferred seven coordination of uranium. 相似文献
995.
The results of a differential scanning calorimetric study of the transitions involving the various polymorphs of Na2SO4 are described. They are discussed in the light of their crystal structures and also in conjunction with more recently published data regarding these transitions.
Zusammenfassung Die Ergebnisse einer mit Differentialabtastkalorimetrie durchgeführten Untersuchung der Übergänge verschiedener Polymorphe von Na2SO4 werden beschrieben. Sie werden im Hinblick ihrer Kristallstrukturen und im Zusammenhang mit verschiedenen unlängst veröffentlichten Daten bezüglich dieser Übergänge diskutiert.
Résumé On décrit les résultats de l'étude, effectuée par analyse calorimétrique différentielle, des transitions mettant en jeu les diverses formes polymorphes de Na2SO4. Les résultats sont discutés en tenant compte des données récemment publiées sur ces transitions.
. , .相似文献
996.
Polymer films containing a sodium or potassium ion-selective exchanger were coated onto platinum wire and incorporated into a potentiometric arrangement. Comparative results obtained by utilizing different measuring devices, one a conventional pH-meter and the other a field-effect transistor (FET) in series with an electrometer, are discussed. The linear range of either system is comparable with that of other electrochemical techniques. Possible applications of such a device are described. 相似文献
997.
A new alternative system for the oxidation of secondary alcohols to ketones with DMSO/N2H4.H2O/I2/H2O/CH3CN in hydrated media has been developed. The system also selectively oxidizes the secondary alcoholic groups to the corresponding ketones in the presence of primary alcoholic groups present within the same molecule in moderate to very good yields at reflux temperature. 相似文献
998.
Gupta Madan Mohan Srivastava Alpana Tripathi Arvind Kumar Misra Himanshu Verma Ram Kishore 《平面色谱法杂志一现代薄层色谱法》2006,19(4):282-287
JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography (HPTLC) has been used for normal-phase separation of the components of hexane,... 相似文献
999.
1000.
Biswanath Das D. Nandan Kumar Keetha Laxminarayana B. Ravikanth 《Helvetica chimica acta》2007,90(7):1330-1334
The synthesis of 14‐aryl‐ or 14‐alkyl‐14H‐dibenzo[a,j]xanthenes 3 involving the treatment of naphthalen‐2‐ol ( 1 ) with arenecarboxaldehydes or alkanals 2 in the presence of HClO4?SiO2 as a heterogeneous catalyst was achieved (Table 1), and this reaction was extended to the preparation of N‐[(2‐hydroxynaphthalen‐1‐yl)methyl]amides 5 by a three‐component reaction with urea ( 4a ) or an amide 4b – d as a third reactant (Table 2). 相似文献