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The characterisation by radiothermoluminescence /RTL/ method of alumina TA 600 catalyst used for 1-butene isomerisation in cis- and trans-2-butene is described. The glow curve, the RTL parameters and the catalyst-reactant radiative coupling evidenced by RTL method are presented. Using the correlation between catalytic activity and RTL data a catalytic activity model is suggested. On the basis of such a model the importance of the structural defects of the catalyst and/or support for the catalytic activity is explained.  相似文献   
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The midside node sensitivity of eight-node isoparametric element in 3-D BEM is investigated. The paper points out that the suggestion, based upon which the midside nodes should be located in the middle third of distance between the adjacent corners, should be followed even more strictly for the conventional isoparametric transformation (CIT) in BEM as that in FEM. A new coordinate transformation relation has been put forward to solve the singular integral problem. The computation is carried to two cases: a cubic body subjected to tensile stress and pure bending. The numerical results show that the improved isoparametric transformation (IIT) is easier and more flexible to practice.  相似文献   
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We consider the Riemann-Hilbert correspondence on the complement of a normal surface singularity (X,x). Through a closure operation we obtain a correspondence between the category of finite dimensional representations of the local fundamental group and the category of left DX,x-modules that are reflexive as OX,x-modules. We show that under this correspondence profinite representations correspond to invariant modules and that these admit a canonical structure as left DX,x-modules. We prove that the fundamental module is an invariant module if and only if (X,x) is a quotient singularity. Finally we investigate some algebraisation aspects.  相似文献   
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A sample preparation device for microanalysis and trace analysis based on acoustic levitation is described. Derivatization can be performed in a single levitated drop as part of the sample pretreatment in an analytical procedure. The applicability of the experimental setup is demonstrated. First results of the preconcentration of hexachlorobenzene are given. Received: 20 August 1999 / Accepted: 7 September 1999  相似文献   
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A sample preparation device for microanalysis and trace analysis based on acoustic levitation is described. Derivatization can be performed in a single levitated drop as part of the sample pretreatment in an analytical procedure. The applicability of the experimental setup is demonstrated. First results of the preconcentration of hexachlorobenzene are given.  相似文献   
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The front-tracking method for hyperbolic conservation laws is combined with operator splitting to study the shallow water equations. Furthermore, the method includes adaptive grid refinement in multidimensions and shock tracking in one dimension. The front-tracking method is unconditionally stable, but for practical computations feasible CFL numbers are moderately above unity (typically between 1 and 5). The method resolves shocks sharply and is highly efficient. The numerical technique is applied to four test cases, the first being an expanding bore with rotational symmetry. The second problem addresses the question of describing the time development of two constant water levels separated by a dam that breaks instantaneously. The third problem compares the front-tracking method with an explicit analytic solution of water waves rotating over a parabolic bottom profile. Finally, we study flow over an obstacle in one dimension.  相似文献   
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