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Wide Potential (wide + potential)
Selected AbstractsA novel semi-empirical topological descriptor Nt and the application to study on QSPR/QSARJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2007Congyi Zhou Abstract A novel semi-empirical topological descriptor Nt was proposed by revising the traditional distance matrix based on the equilibrium electronegativity and the relative bond length. Nt can not only efficiently distinguish structures of organic compounds containing multiple bonds and/or heteroatoms, but also possess good applications of QSPR/QSAR (quantitative structure-property/activity relationships) to a large diverse set of compounds, which are alkanes, alkenes, alkynes, aldehydes, ketones, thiols, and alkoxy silicon chlorides with all the correlation coefficients of the models over 0.99. The LOO CV (leave-one-out cross-validation) method was used to testify the stability and predictive ability of the models. The validation results verify the good stability and predictive ability of the models employing the cross-validation parameters: RCV, SEPCV and SCV, which demonstrate the wide potential of the Nt descriptor for applications to QSPR/ QSAR. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007 [source] Synthesis of a 13C labeled N -cyclopropylamine tetrahydropyridine derivativeJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 10 2002Simon Kuttab Abstract The synthesis of 1-(2- 13C)-cyclopropyl-4-phenyl-1,2,3,6-tetrahydropyridine (8) is reported. Attempts were first made to prepare labeled cyclopropylamine via a cyclopropanation/Curtius rearrangement sequence, but the yields were too modest to be suitable for the synthesis of a labeled compound. The preparation of 8 was achieved via cyclopropanation of the N -formyl tetrahydropyridine derivative 21 using the Grignard reagent of ethyl bromide and Ti(O- iPr)4 as a catalyst. The synthesis proceeded in high yield (82%). The method has a wide potential for the synthesis of other cyclopropyl ring labeled and substituted cyclopropyl ring labeled tetrahydropyridine dervatives which can be used in Monoamine Oxidase (MAO) and Cyt P450 enzymes mechanistic studies. Copyright © 2002 John Wiley & Sons, Ltd. [source] An automated method for ,clumped-isotope' measurements on small carbonate samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2010Thomas W. Schmid Clumped-isotope geochemistry deals with the state of ordering of rare isotopes in molecules, in particular with their tendency to form bonds with other rare isotopes rather than with the most abundant ones. Among its possible applications, carbonate clumped-isotope thermometry is the one that has gained most attention because of the wide potential of applications in many disciplines of earth sciences. Clumped-isotope thermometry allows reconstructing the temperature of formation of carbonate minerals without knowing the isotopic composition of the water from which they were formed. This feature enables new approaches in paleothermometry. The currently published method is, however, limited by sample weight requirements of 10,15,mg and because measurements are performed manually. In this paper we present a new method using an automated sample preparation device coupled to an isotope ratio mass spectrometer. The method is based on the repeated analysis (n,=,6,8) of 200,µg aliquots of sample material and completely automated measurements. In addition, we propose to use precisely calibrated carbonates spanning a wide range in ,47 instead of heated gases to correct for isotope effects caused by the source of the mass spectrometer, following the principle of equal treatment of the samples and standards. We present data for international standards (NBS 19 and LSVEC) and different carbonates formed at temperatures exceeding 600°C to show that precisions in the range of 10 to 15,ppm (1 SE) can be reached for repeated analyses of a single sample. Finally, we discuss and validate the correction procedure based on high-temperature carbonates instead of heated gases. Copyright © 2010 John Wiley & Sons, Ltd. [source] Calculation of profile of charge carrier concentration in modulation doped structure with a wide potential wellANNALEN DER PHYSIK, Issue 12 2009L.Yu. Shchurova Abstract We investigate the equilibrium state of interacting electron system with Fermi statistics in modulation doped structure with a wide quantum well. The model is formulated for the carrier system with a sufficiently high density, such that the de Broglie wavelength of electrons is smaller than the width of the quantum well. Due to a significant interaction of electrons with electric field of the doped layer, a state with strongly-inhomogeneous density of electrons is formed. Within the hydrodynamic approach, we set up formalism for calculating the electron density across the width of the potential well. We have obtained the exact solution of the equations, which is expressed in terms of hypergeometric functions. Based on the deduced formulas, we performed numerical computations for the profile of carriers' concentrations in a potential well in the modulation doped Si/SiGe/Si structures. [source] | ||||||||||