不协调目标信息系统知识约简的比较研究

研究不协调目标信息系统的各种知识约简之间的关系。证明分布约简既是β上分布约简，也是β下分布约简，并且在一定条件下,β上、下分布约简与不协调目标信息系统的分配约简和最大分布约简等价。     

Characterization of porosity in a 19th century painting ground by synchrotron radiation X-ray tomography

The study of the early oeuvre of the Swiss painter Cuno Amiet (1868–1961) has revealed that, up to 1907, many of his grounds were hand applied and are mainly composed of chalk, bound in protein. These grounds are not only lean and absorbent, but also, as Synchrotron radiation X-ray microtomography has shown, porous. Our approach to the characterization of pore structure and quantity, their connectivity, and homogeneity is based on image segmentation and application of a clustering algorithm to high-resolution X-ray tomographic data. The issues associated with the segmentation of the different components of a ground sample based on X-ray imaging data are discussed. The approach applied to a sample taken from “Portrait of Max Leu” (1899) by Amiet revealed the presence of three sublayers within the ground with distinct porosity features, which had not been observed optically in cross-section. The upper and lower layers are highly porous with important connectivity and thus prone to water uptake/storage. The middle layer however shows low and nonconnected porosity at the resolution level of the X-ray tomography images, so that few direct water absorption paths through the entire sample exist. The potential of the method to characterize porosity and to understand moisture-related issues in paint layer degradation are discussed.     

对超重、失重演示实验的改进

对传统的超重、失重演示实验进行了改进,使弹簧秤的指针能静止在超重(或失重)的位置上,从而能准确地读出读数,提高演示效果.     

Critical Evaluation of Analytical Procedures for the Determination of Lead in Seawater

Abstract: This article presents a critical evaluation of the analytical procedures used for the determination of lead in seawater, which is important because lead is a good indicator of marine pollution caused by human activities. Sampling, storage, and pretreatment techniques are briefly overviewed, including the significance of systematic errors that cannot be corrected later on. The main techniques in this article are electrothermal–atomic absorption spectrometry (ET-AAS), inductively coupled plasma–mass spectrometry (ICP-MS), and voltammetry. Flame atomic absorption spectrometry (FAAS) and inductively coupled plasma–optical emission spectrometry (ICP-OES) are treated as well, although their limits of quantification are not sufficient for a determination of lead in unpolluted seawater. Even when separation and preconcentration techniques are applied, these techniques are only capable of detecting lead in polluted coastal seawater. Separation and preconcentration are actually also required for ET-AAS and ICP-MS in order to determine the lowest concentrations of lead found in unpolluted open-ocean seawater, which is still a challenge for the analytical chemist.     

Non-compact symmetric spaces and the Toda molecule equations

It has been shown by Olshanetsky and Perelomov that the Toda molecule equations associated with any Lie groupG describe special geodesic motions on the Riemannian non-compact symmetric space which is the quotient of the normal real form ofG, G ^N, by its maximal compact subgroup. This is explained in more detail and it is shown that the fundamental Poisson bracket relation involving the Lax operatorA and leading to the Yang-Baxter equation and integrability properties is a direct consequence of the fact that the Iwasawa decomposition forG ^N endows the symmetric space with a hidden group theoretic structure.Supported by CNP _q (Brasil)     

基于PSD的微摆镜角度自准直测试系统设计

基于压电陶瓷的微摆镜是一种典型的二维角驱动部件,微摆镜系统的实用化需要进行微角度的测量,以便得到驱动电压与微偏转角之间的对应关系。设计了一种基于位置敏感探测器(PSD)的微摆镜角度测试系统,应用激光自准直原理,采用两次45°折返式结构,缩小了系统的体积并解决了传统折返式系统难以精准搭建的问题;采用多层前馈神经网络法对PSD进行了非线性校正,修正后整个系统的测量精度可达0.5″,测量范围为±400″。符合微摆镜角度测量的要求。     

镱的原子吸收分析进展

本文对近些年来用电热原子吸收和火焰原子吸收测定镱时,为提高镱的灵敏度而采用的各种方法进行总结评述。     

Cathodic and anodic pre-treated boron doped diamond with different sp content: Morphological,structural, and impedance spectroscopy characterizations

In this work, the influence of cathodic (Red) and anodic (Ox) pre-treatment on boron doped diamond (BDD) films grown with different sp²/sp³ ratios was systematically studied. The sp²/sp³ ratios were controlled by the addition of CH₄ of 1,3,5 and 7 sccm in the gas inlet during the growth process. The electrodes were treated in 0.5 mol L⁻¹ H₂SO₄ at −3 and 3 V vs Ag/AgCl, respectively, for 30 min. The electrochemical response of BDD films was investigated using electrochemical impedance spectroscopy (EIS) and Mott–Schottky Plot (MSP) measurements. Four film sample sets were produced in a hot filament chemical vapor deposition reactor. During the growth process, an additional H₂ line passing through a bubbler containing the B₂O₃ dissolved in methanol was used to carry the boron. The scanning electron microscopy morphology showed well faced films with a small decrease in their grain size as the CH₄ concentration increased. The Raman spectra depicted a pronounced sp² band, mainly for films with 5 and 7 sccm of CH₄. MSP showed a decrease in the acceptor concentration as the CH₄ increased indicating the CH₄ influence on the doping process for Red–BDD and Ox–BDD samples. Nonetheless, an apparent increase in the acceptor concentrations for both Ox–BDD samples was observed compared to that for Red–BDD samples, mainly attributed to the surface conductive layer (SCL) formation after this strong oxidation process. The EIS Nyquist plots for Red–BDD showed a capacitance increase for the films with higher sp² content (5 and 7 sccm). On the other hand, the Nyquist plots for Ox–BDD can be described as semicircles near the origin, at high frequencies, where their charge transfer resistance strongly varied with the sp² increase in such films.     

中波红外3 μm～5 μm宽带通滤光片的研制

 中波红外宽带通滤光膜通常膜系层数多,膜层总厚度非常大（厚度达到10 μm左右）,膜层的镀制工艺难度较大。通过分析红外带通滤光片几种设计方法的特点,并结合实际镀制工艺技术,采用了长波通与短波通及非规整薄膜设计技术相结合的方法,设计了以锗材料为基底的中波3 μm～５ μm宽带通滤光膜。该设计大幅度降低了膜层的总厚度（约为8.65 μm）,缩短了膜层的镀制周期,提高了膜层的牢固度;在膜层的镀制工艺过程中,通过改变薄膜材料的蒸发速率、修正蒸发硫化锌材料时电子枪的扫描方式、调整蒸发材料在坩埚中的装载方法,使膜层获得了优异的光谱性能,其通带平均透过率大于96%,截止区域的平均透过率小于1%。