N-Centralizing Mappings in Semiprime Rings

Ｎ┐ＣｅｎｔｒａｌｉｚｉｎｇＭａｐｐｉｎｇｓｉｎＳｅｍｉｐｒｉｍｅＲｉｎｇｓＭａｊｅｅｄ，Ａ．Ｈ．ａｎｄＮｉｕＦｅｎｇｗｅｎ（牛凤文）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＪｉｌｉｎＵｎｉｖｅｒｓｉｔｙ，Ｃｈａｎｇｃｈｕｎ，１３００２３）...     

显微红外光谱填图法示踪中国三个产地的天然钻石中氮杂质的非均匀生长

钻石产地特征研究在了解地幔演化及遏制国际冲突钻石非法交易等方面具有重要意义,采用傅里叶变换显微红外光谱技术对采自中国三个商业性产地的14片天然IaAB型钻石进行了系统的面扫描分析,根据显微红外光谱谱图定量计算出钻石中的氮含量(1 616个红外测试数据)并进行填图示踪。结果表明,钻石生长过程中氮的含量和聚集度不断变化,且成核阶段氮含量可高于或低于其他生长阶段,不同生长阶段氮杂质含量不具有单向变化规律,显示钻石生长过程中地幔流体碳和氮存在复杂的交换,不同产地钻石中氮含量频率分布及NB%/N(T)特征存在一定的区域性差异,与跳点法红外光谱测试相比,面扫描法填图能更直观和连续的示踪钻石生长过程中氮杂质的不均匀生长。     

半广义连续映射

这篇文章, 我们定义半广义连续映射, 研究它的一些性质, 给出它的等价刻画.     

Affine Configurations and Pure Braids

We show that the fundamental group of ordered affine-equivalent configurations with at least five points in the real plane is isomorphic to the pure braid group in as many strands, modulo its centre. In the case of four points, this fundamental group is free with 11 generators. This work was carried out at the Instituto de Matemáticas, UNAM and partially funded by the Sistema Nacional de Investigadores and a doctoral fellowship from CONACyT México.     

Computable Carathéodory Theory

The conformal Riemann mapping of the unit disk onto a simply-connected domain W is a central object of study in classical Complex Analysis. The first complete proof of the Riemann Mapping Theorem given by P. Koebe in 1912 is constructive, and theoretical aspects of computing the Riemann map have been extensively studied since. Carathéodory Theory describes the boundary extension of the Riemann map. In this paper we develop its constructive version with explicit complexity bounds.     

Cremona transformations and diffeomorphisms of surfaces

We show that the action of Cremona transformations on the real points of quadrics exhibits the full complexity of the diffeomorphisms of the sphere, the torus, and of all non-orientable surfaces. The main result says that if X is rational, then Aut(X), the group of algebraic automorphisms, is dense in Diff(X), the group of self-diffeomorphisms of X.     

Using X-PEEM to study biomaterials: Protein and peptide adsorption to a polystyrene–poly(methyl methacrylate)-b-polyacrylic acid blend

Recent synchrotron-based soft X-ray photoemission electron microscopy (X-PEEM) studies of protein and peptide interaction with phase segregated and patterned polymer surfaces in the context of optimization of candidate biomaterials are reviewed and a study of a new system is reported. X-PEEM and atomic force microscopy (AFM) were used to investigate the morphology of a phase-segregated thin film of a polystyrene/poly(methyl methacrylate)-b-polyacrylic acid (PS/PMMA-PAA) blend, and its interactions with negatively charged human serum albumin (HSA) and positively charged SUB-6 (a cationic antimicrobial peptide, RWWKIWVIRWWR-NH₂) at several pHs. At neutral pH, where the polymer surface is partially negatively charged, HSA and SUB-6 peptide showed contrasting adsorption behavior which is interpreted in terms of differences in their electrostatic interactions with the polymer surface.     

A new spectral calibration method for Fourier domain optical coherence tomography

Spectral calibration is important for a Fourier domain optical coherence tomography (FD-OCT) system. A new spectral calibration method for FD-OCT is presented. Through the iterated mapping of spectral interferograms detected by an optical spectrum analyzer and the CCD grating spectrometer, multiple groups of calibration coefficients are obtained. By comparing the effects of these coefficients on improving the amplitude of the axial point spread function (PSF), optimum coefficients are obtained. In this method, no additional calibration laser source is needed, reducing the complexity of the system. The cross-sectional images of a glass plate in milk are acquired, and the experimental results indicate that the axial resolution and signal-to-noise ratio (SNR) are effectively improved with the proposed spectral calibration method.     

广义复数上的函数

本文用复变函数方法统一讨论既含椭圆型也含双曲型的一类线性偏微分方程。可以看到它们的许多个性寓于其共性之中。     

Matching arc complexes: Connectedness and hyperbolicity

Addressing a question of Zaremsky, we give conditions on a finite simplicial graph which guarantee that the associated matching arc complex is connected and hyperbolic.