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This paper discusses two problems from important areas of processmodelling, namely injection moulding and resin film infusion.The first comes from the food-processing sector, and involvesthe filling of tubs with liquid foodstuffs. The approach takenhere is computational, with the foodstuffs modelled as incompressibleviscous (Newtonian or non-Newtonian) fluids. In practice, theliquids have multiple free surfaces; the correct treatment ofthese surfaces is a crucial element of the modelling herein. Resin film infusion is one of the preferred processes for themanufacture of composite materials. In essence it involves squeezinga viscous incompressible fluid into a woven carbon-fibre matrix.With the matrix treated as a porous medium, and with exothermicreactions (and consequent thermal effects) neglected, simpleanalytical results are obtainable which can be verified by straightforwardengineering experiments.  相似文献   
2.
Ab initio calculations at the B3LYP, MP2, MP4 and CCSD(T) levels of theory were performed to predict the stability of the halooxyhalocarbenes, XOCX (X = F, Cl). The calculations indicate that the nonlinear FOCF molecule is stable with an energy 16 kJ mol?1 below the energy of possible reacting fragments F2 and CO. However, a nonlinear equilibrium structure for ClOCCl was located, but it was found to be about 192 kJ mol?1 higher in energy than the energy of Cl2 and CO. The charge distribution in these molecules was analysed using the atoms in molecules (AIM) method.  相似文献   
3.
Phosphine-catalyzed [4+2] annulations of 2-(acetoxymethyl)buta-2,3-dienoates with α-aminonitriles have been developed, in which α-aminonitriles serve as C, N-bisnucleophilic reaction partners and 2-(acetoxymethyl)buta- 2,3-dienoates as "C4 synthons" respectively. A number of α-aminonitriles could be successfully applied to giving multifunctional desired products using PPh3 as catalyst. This method provides a facile entry to access polysubstituted tetrahydropyridines bearing quaternary carbon centers. The possible reaction mechanism was also proposed.  相似文献   
4.
The rotational spectra of five isotopomers of the ethylene-OCS dimer have been observed by Fourier transform microwave spectroscopy and its structure was determined. The dipole moment components and rotational constants for this complex are consistent with a stacked geometry in which the OCS lies above the ethylene molecular plane, approximately parallel to the C=C bond. Two internal motions of the monomer subunits split each rotational transition into four components. The larger tunneling splittings have been analysed to give a twofold barrier for the internal motion of the ethylene subunit about its c inertial axis of 16(3) cm?1. The results are compared with calculations with a semi-empirical model employing electrostatic, dispersion and repulsion interactions.  相似文献   
5.
This paper presents a general convergence analysis of numericalmethods for solving ordinary differential equations and non-linerVolterra integral and integrodifferential euqations. The conceptof analytic and discrete forms is introduced, Prolongation andrestriction operators reduce the problem of comparing the fundamentalforms. Integral inequalities and their discrete analogues proofof a collocation method for solving Volterra integral equationsof the second kind.  相似文献   
6.
In this part one of a series of papers, we introduce a new version of quantum covering and super groups with no isotropic odd simple root, which is suitable for the study of integrable modules, integral forms, and the bar involution. A quantum covering group involves parameters q and π with π2?=?1, and it specializes at π?=??1 to a quantum supergroup. Following Lusztig, we formulate and establish various structural results of the quantum covering groups, including a bilinear form, quasi- $ \mathcal{R} $ -matrix, Casimir element, character formulas for integrable modules, and higher Serre relations.  相似文献   
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