Characterisation of the Kratos Axis Ultra with spherical mirror analyser for XPS imaging

The imaging performance of an XPS instrument employing a spherical mirror electron energy analyser has been characterised by measuring the peak position, full width at half maximum (FWHM), and lineshape, at every pixel in the image, for different modes of operation. Changes in these parameters have been identified and recommendations made for quantification of, and chemical state determination from, spectrum image data sets. Copyright © 2006 John Wiley & Sons, Ltd.     

Exact electronic properties in the classically forbidden region of a metal surface

We derive exact properties of the inhomogeneous electron gas in the asymptotic classically forbidden region at a metal–vacuum interface within the framework of local effective potential energy theory. We derive a new expression for the asymptotic structure of the Kohn–Sham density functional theory (KS‐DFT) exchange‐correlation potential energy v_xc(r) in terms of the irreducible electron self‐energy. We also derive the exact asymptotic structure of the orbitals, density, the Dirac density matrix, the kinetic energy density, and KS exchange energy density. We further obtain the exact expression for the Fermi hole and demonstrate its structure in this asymptotic limit. The exchange‐correlation potential energy is derived to be v_xc(z → ∞) = ?α_KS,xc/z, and its exchange and correlation components to be v_x(z → ∞) = ?α_KS,x/z and v_c(z → ∞) = ?α_KS,c/z, respectively. The analytical expressions for the coefficients α_KS,xc and α_KS,x show them to be dependent on the bulk‐metal Wigner–Seitz radius and the barrier height at the surface. The coefficient α_KS,c = 1/4 is determined in the plasmon‐pole approximation and is independent of these metal parameters. Thus, the asymptotic structure of v_xc(z) in the vacuum region is image‐potential‐like but not the commonly accepted one of ?1/4z. Furthermore, this structure depends on the properties of the metal. Additionally, an analysis of these results via quantal density functional theory (Q‐DFT) shows that both the Pauli W_x(z → ∞) and lowest‐order correlation‐kinetic W(z → ∞) components of the exchange potential energy v_x(z → ∞), and the Coulomb W_c(z → ∞) and higher‐order correlation‐kinetic components of the correlation potential energy v_c(z → ∞), all contribute terms of O(1/z) to the structure. Hence correlations attributable to the Pauli exclusion principle, Coulomb repulsion, and correlation‐kinetic effects all contribute to the asymptotic structure of the effective potential energy at a metal surface. The relevance of the results derived to the theory of image states and to KS‐DFT is also discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Sampling and local models for multivariate image analysis

Local models are a very important concept for microscopic and macroscopic imaging. Different methods of sub-sampling a multivariate image are described both in general and for three examples. The need for sub-sampling and its influence on multivariate image analysis and visualization are studied. Examples from MRI (256 × 256), satellite imaging (7 × 512 × 512) and biofuel studies (6 × 512 × 512) are used to illustrate some of the principles involved.     

Synthesis and characterisation of bis(pentafluorophenyl)antimony(V) cations, [(C6F5)2SbL3]

Pentacoordinate complex cations of the general formula [(C₆F₅)₂SbL₃]³⁺ stabilized as solid salts in combination with tetraphenylborate (BPh₄), tetrafluorobroate (BF₄) anions, where L=DMSO, Ph₃AsO, PyO, DMF, α-, β- and γ-picoline have been isolated. The newly formed complexes were characterized by elemental analysis, molar conductance measurements, solid-state IR and and NMR. From these results, a five-fold coordination around antimony was required.     

SiO2包覆纳米CaCO3的透射电镜表征

在透射电子显微镜（TEM）电子衍射模式下，用适当孔径的物镜光阑选择非晶态SiO2的衍射区域，拍摄以溶胶一凝胶法制备的SiO2包覆纳米CaCO3的暗场像。与未经包覆SiO2的纳米CaCO3的暗场像作对比，可以看出经过SiO2包覆的纳米CaCO3粒子周围有一白色亮环，从而得到SiO3包覆层的暗场照片。用高分辨方法观察了包覆层与CaCO3粒子间的界面情况。     

溴碘化银薄片乳剂颗粒中碘离子分布对潜影分散的影响

碘溴化银乳剂薄片颗粒的潜影分散与碘离子在颗粒中的分布有关。本文用交叉光楔曝光技术测定了由次潜影造成的潜影分散,并根据所测出的潜影分散度和乳剂的表面感光度,对内、表敏的分布作了分析。结果表明,碘离子分布在颗粒边缘的乳剂,其表面潜影分散度要比碘离子均匀分布的颗粒更甚,后者且表现出内、表敏度竞争的现象。     

Comparison of methods to enhance flame ionization detector (FID) signals in gas chromatography

The performances of some numerical methods to improve the signal to noise ratio are compared and applied to enhance noisy signals obtained in gas chromatography with capillary columns and a flame Ionization detector. Several methods have been considered: cutoffs In the Fourier transform of the recorded signal; real time numerical filtering; theoretical model curve fitting; and the correlation of a chromatogram recorded from a pseudorandomly injected sample with the pseudorandom injection function. Numerical real time filtering is shown to be the most convenient method when the main periodic component of the noise has been determined by Fourier analysis.     

岩石的核磁共振自旋密度微成像

岩，心是油气储层的基本单元，其内部结构和渗流性质反映了油藏的基本特征．岩。心的精细描述是油藏描述、储层动态监测及设计强化采油方案的重要基础．本文利用核磁共振（NMR）自旋密度做成像，快速无损地观测到两类基本储油岩石——砂岩和灰岩的内部结构，提供了岩石渗透性、孔隙性及灰岩沉积环境等重要信息．1实验方法以自旋回波单片NMR成像脉冲序列为基础，设。P平面内样品的目施密度为P（。，v）．演化期t。，在。方向梯度场G。作用下，各处横向磁化矢量获得的相移为式中，7为共振核（在成像中一般为质子）的旋磁比，g为坐标位置·…     

Hydrothermal Synthesis, Crystal Structure, and Characterization of a Novel Terbium（Ⅲ） Coordination Polymer Bridged by 5-Sulfoisophthalate Trivalent Anions

Introduction Recently, several efforts have been made for thestudy of coordination polymers assembled from lantha-nide ions and aromatic polycarboxylate ligands becauseof their intriguing structural diversity and potentialapplications in several fields, s…