Finite-length mask effects in the isolation oxidation of silicon

Author to whom all correspondence should be addressed A moving-boundary problem modelling the two-dimensional isolationoxidation of silicon is analysed in the limit of reaction-controlledoxidation for a finite-length nitride mask. Encroachment underthe mask caused by silicon oxidation then occurs from both sidesto produce two ‘bird's beaks’, and it is the interactionbetween these beaks on which attention is focused. This effect,termed ‘bird's beak punchthrough’, is currentlyof interest in submicron silicon-isolation technologies.     

电子与正电子散射的辐射修正

With the Mφller's theory of scattering between the electrons and the Dirac's hole theory, Bhabha has obtained the formula for the scattering of the electrons and the positrons. The experimental evidence of this phenomenon was discovered by Ho (何泽慧), and she has studied this phenomenon by means of the β⁺-radioactivity of the β⁺ sources such as Mn⁵², and F¹⁸ in the cloud chamber. The comparison of the theory and the experiment was done (see reference [2], [3], [4], [5] and [6].) by Ho, O. Ritter et al, R. R. Roy and L. Groven, G. R. Hoke and A. Ashkin et al.The purpose of the present work is to show the effect of the radiative corrections to the scattering of the electrons and the positrons by the method in the quantum electrodynamics developed by S. Tomonaga, J. Schwinger, R. P. Feynman and F. J. Dyson.In the above-mentioned electron and positron scattering experiments, the contributions to the scattering cross-section are mostly due to the positrons of low energies (about 0.1 to 0.2 Mev). In this energy range, the exchange effect in Bhabha's theory is small. In this work for the radiative corrections to the scattering of the electrons and the positrons, we have neglected this exchange effect. The ratio of the correction of the scattering cross-section due to the radiative corrections to the scattering cross-section of Bhabha's theory at this energy range does not exceed 1%. For experiments of the low energy positrons and of the higher energy positrons (e.g positrons with energies of 0.5 Mev to 1 Mev as in the experiment of Ashkin et al) with small exchanges of energy between the electrons and the positrons during scattering, our calculation is adequate. But for positrons of higher energies and with large exchanges during scattering, our calculation should be improved by considering the exchange effect.     

Kinetic energy functionals for molecular calculations

The orbitals and eigenvalues of a Kohn-Sham density functional theory calculation can be used to determine the kinetic potential, the functional derivative of the non-interacting kinetic energy. Thus, approproximate kinetic energy functionals can be systematically parameterized to improve their functional derivatives. Fitting procedures have been applied to various functional forms and the quality of the resulting functionals investigated using variationally optimized densities. The best functionals include the full correction of Weizsäcker and a modulation of the Thomas-Fermi p^5/3 term by a function of the distance from the nucleus. These atom-specific functionals predict virtually exact shell structure, and may be combined readily into a functional which supports molecular binding.     

SYSTEMIC IMMUNOSUPPRESSION INDUCED BY PHOTODYNAMIC THERAPY (PDT) IS ADOPTIVELY TRANSFERRED BY MACROPHAGES

Some derivatives of hematoporphyrins are strongly retained by tumor tissue as compared to normal tissue, and exposure of these photosensitizers to radiation in the visible spectrum can cause serious biological damage. These properties have been exploited in the development of a new treatment for cancer termed photodynamic therapy (PDT). However, recent studies have also demonstrated that PDT can also induce a state of systemic immunosuppression. The purpose of this study was to determine whether PDT-induced suppression of contact hypersensitivity (CHS) responses was an active phenomenon that could be adoptively transferred by viable splenocytes from PDT-treated mice. Although induction of adoptively transferable suppressor cells in PDT-treated mice required exposure to antigen, the suppressor cells were found to be antigen nonspecific in their function. Furthermore, splenocytes from PDT-treated mice were capable of generating levels of allospecific cytotoxic T lymphocyte (CTL) activity which were comparable to those generated by normal control mice, but the ability of irradiated spleen cells from PDT-treated mice to stimulate a mixed lymphocyte response (MLR) was dramatically impaired. Finally, chromatographic separation of T cells, B cells and macrophages showed that the cell type which mediates adoptively transferable suppression of CHS responsiveness is in the macrophage lineage.     

A Method for the Numerical Solution of Problems Governed by Elliptic Systems in the Cut Plane

A method is derived for the numerical solution of boundary-valueproblems governed by systems of second order linear ellipticpartial differential equations in two independent variables.The boundary of the region in ²under consideration is requiredto consist of two parts. The first part is a straight cut offinite length while the second part C consists of an arbitrarycontour surrounding The solution to a particular boundary-valueproblem is expressed in terms of an integral taken around C.This integral may be evaluated numerically. The method shouldbe particularly useful for the solution of crack problems inanisotropic thermostatics and elastostatic     

一类逐段决定风险模型罚金函数的期望(英)

本文主要考虑了一类逐段决定的风险模型的罚金函数.利用建立的积分-微分方程,我们得出了此类风险模型罚金函数期望的一般解.