光交联聚乙烯材料的光稳定性研究

本文中用紫外光敏化的方法对低密度聚乙烯进行了交联,并利用ESCA和ATR-IR等手段研究了交联后材抖的光稳定性及其改进办法。     

The Unmixing Problem

High-gain adaptive stabilization of minimum-phase linear systemsraises the so-called unmixing problem: finding a finite setA of matrices, with the property that for any M GL(n), (AM)C₊ for at least one A . First, some preliminary results will be given, leading up to a non-constructive proofof the existence of such finiteA's. For the cases n = 2 and3, a fairly satisfying solution is presented. In higher dimensions,the situation is more complicated, and negative results aregiven. Based on the Euler angles for O(n), an explicit solutionis given for arbitrary n.     

Electrical impedance spectroscopy and electrical response in metal/non-metal systems

A new analysis of the electrical response of a macroscopic solid state system to an arbitrary electrical voltage input is presented. The results indicate that with a small, sinusoidal voltage input within the classical frequency range (ω < 10¹⁰Hz), the electrical response in spatially homogeneous systems mirrors first of all the static, spatial distribution of the mobile charge carrier density through the local electrical conductivity relaxation time. This enables any system, inclusive interface and electrical contact regions to be modelled by a simple, passive R, C electrical network, where each of the network elements has a very direct physical meaning. Ultra pure, single crystal silicon, pure polycrystalline silicon and Al-Al₂O₃-Au metal-insulator-metal (MIM) structure are used as illustrative examples.     

GH302合金中C14型Laves相的会聚束电子衍射研究

用会聚束电子衍射、选区电子衍射和X射线微区分析,将GH302合金中的枝晶状析出相确认为C14型Laves相。 关键词：     

Full configuration interaction studies of phonon and photon transition rates in semiconductor quantum dots

Quantum chemical methods originally developed for studying atomic and molecular systems can be applied successfully to the study of few-body electron-hole systems in semiconductor nanostructures. A new computational approach is presented for studying the energetics and dynamics of interacting electrons and holes in a semiconductor quantum dot. The electron-hole system is described by a two-band effective mass Hamiltonian. The Hamiltonian is diagonalized in a configuration state function basis constructed as antisymmetric products of the electron one-particle functions and antisymmetric products of the hole one-particle functions. The symmetry adapted basis set used for the expansion of the one-particle functions consists of anisotropic Gaussian basis functions. The transition probability between electron-hole states consisting of different numbers of carrier pairs is calculated at the full configuration interaction level. The results show that the electron-hole correlation affects the radiative recombination rates significantly. A method for calculating the phonon relaxation rates between excited states and the ground state of quantum dots is described. The phonon relaxation calculations show that the relaxation rate is strongly dependent on the energy level spacings between the states.