X-ray microanalysis of 1.5-10 μm particles in metallurgical research

The importance of particle X-ray microanalysis for contemporary metallurgical research has been accentuated. Corrections in the formulae for the geometric modelling method and simplifications in the calculation procedure are introduced. Conditions for successful application of the peak to background ratio method were outlined. Besides these two methods related to isolated particles a new extrapolation method for matrix embedded particles is developed and comments to the particle weight fraction estimation method for the same kind of particles are given.     

The Aluffi algebra of hypersurfaces with isolated singularities

The Alu? algebra is an algebraic definition of a characteristic cycle of a hypersurface in intersection theory. In this paper, we study the Alu? algebra of quasi-homogeneous and locally Eulerian hypersurfaces with only isolated singularities. We prove that the Jacobian ideal of an a?ne hypersurface with isolated singularities is of linear type if and only if it is locally Eulerian. We show that the gradient ideal of a projective hypersurface with only isolated singularities is of linear type if and only if the a?ne curve in each a?ne chart associated to singular points is locally Eulerian. We show that the gradient ideal of Nodal and Cuspidal projective plane curves are of linear type.     

An Algebraic Characterization of Blumberg Spaces

Abstract

Let X be a topological space and let C(X) be the ring of continuous real-valued functions on X. We study T′(X) as an over-ring of C(X), where T′(X) denotes the set of all real-valued functions on X such that for each f ∈ T′(X) there exists a dense open subspace D of X such that f|D ∈ C(D). In this paper new algebraic characterizations of discrete spaces, open-hereditarily irresolvable spaces, and Blumberg spaces are obtained.     

Theoretical investigation of high-order harmonic generation from asymmetric molecular ions in the chirped laser field

High-order harmonic generation from the asymmetric helium hydrogen molecular ion exposed to a few-cycle chirped laser field is theoretically investigated by numerically solving the reduced one-dimension non-Born–Oppenheimer time dependent Schrödinger equation. The numerical results show that the plateau of the high-order harmonic spectrum is dramatically broadened and smoother with the introduction of the chirp. Further study presents that only the short quantum path contributes to harmonic emission and the long quantum path disappears in the chirped laser. In addition, an 80-as isolated attosecond pulse is obtained by superposing the harmonics from the 100th to the 130th order in the chirped field. The time-frequency distributions and the electronic probability distributions are presented to explain the underlying physical mechanism.     

Enhancement of High-Order Harmonic Emission and Isolated 7-as Pulse Generation with Rydberg Atoms by Using a Two-Color Laser Field

An efficient method to enhance the harmonic efficiency and generate an isolated attosecond pulse is proposed by preparing the initial state as a coherent superposition of the ground state and a Rydberg state in a two-color laser field. By numerically solving the time-dependent Schrödinger equation, we found that for the superposition state with the optimal Rydberg state, not only is the harmonic efficiency enhanced significantly, but also the width of the continuous spectrum is extended. The ionization probability and the time-frequency distribution of the harmonic spectrum are also calculated to understand the physical origin of the enhancement of the harmonic spectrum. In addition, by adjusting the parameter of the laser pulse, a supercontinuum with both higher conversion efficiency and slighter modulation can be observed. As a result, an isolated 7-as pulse with a bandwidth of 495 eV can be obtained after phase compensation.     

基于人工神经网络的汉语数字语音识别系统

利用改进的有序聚类算法得到解决时间规整问题的新算法,在此基础上建立了基于人工神经网络的普通话数字语音识别系统。对基于人工神经网络的算法和基于动态时间伸缩的算法作比较识别实验,结果表明,基于人工神经网络的语音识别算法的识别性能优于传统的动态时间伸缩算法。     

红外用CVD ZnS多晶材料的研制

论述了制备红外用CVD ZnS多晶材料的化学气相沉积工艺和热等静压处理工艺。针对CVD ZnS多晶材料具备优良的光学和力学性能,采用化学气相沉积工艺和热等静压处理技术成功研制出大尺寸多晶材料,其最大尺寸达到250mm×15mm。测试了CVD ZnS样品的各项光学、力学性能指标。样品的全波段透过率均接近ZnS材料的本征水平,折射指数均匀性优于2×10^-5,在1.06μm的吸收系数为2×10^-3cm^-1,抗弯强度达到104MPa。     

Peripheral Modifications of meso-Hydroxyporphyrins: Formation of π-Electronic Anions and Ion-Pairing Assemblies

Phenyl groups were introduced at the β-positions proximal to the meso-hydroxy moiety in hydroxyporphyrin Ni^II complexes by oxidized BINAP Pd^II complexes. Ion-pairing assemblies of deprotonated π-electronic anions, anionic site of which was stabilized by the introduced phenyl moieties with a bulky cation, were formed. They showed charge-by-charge assemblies, assembly modes of which were modulated by the anionic building units.     

计算代数方程组孤立奇异解的符号数值方法

求解代数方程组是计算代数几何的最基本问题之一,孤立奇异解的计算则是其中最具挑战性的课题之一,在科学与工程计算中有着广泛的应用,如机器人、计算机视觉、机器学习、人工智能、运筹学、密码学和控制论等.本文结合作者的研究成果,综述了符号数值方法在计算代数系统孤立奇异解、特别是近似奇异解精化与验证方面的研究进展,并对未来的研究方向提出了展望.