The analysis of casework sized alloy fragments by inductively coupled plasma-optical emission spectrometry (ICP-OES) using discrete nebulisation

A discrete nebulisation technique has been developed for the multi-element analysis of 100-μl solution droplets by inductively coupled plasma-optical emission spectrometry (ICP-OES). The technique increases analytical speed and uses very small solution volumes with only a slight degradation in detection limits when compared to continuous solution introduction.To evaluate its suitability in casework, small alloy fragments were produced by cutting with a hacksaw, sample division and filing. The analysis of fragments from two different brasses indicated that quantitative data could be obtained from fragments as small as 10 μg. The accurate determination of lead, a non-homogeneous constituent of leaded brasses, required sample sizes an order of magnitude greater. Analysis of an alloy of fine grain structure (copper-nickel) demonstrated that quantitative data could be obtained from samples weighing a few micrograms or less.     

乡村集体企业的兴衰及“改制”的社会学剖析

乡村集体企业既是中国农民继家庭联产承包责任制之后的又一创举,从某种意义上说也是面对难以突破的城乡二元结构所采取的"无奈"之举。城市改革、国有企业的改革以及大量外资的引入、私营个体经济的高速发展,尤其是买方市场的普遍确立,都直接导致了数以万计的乡村集体企业陷入前所未有的危机。乡村集体企业从整体上的"改制"标志着人民公社体制的最终退出。不能将"超级村庄"作为乡村发展的高级阶段来理解,城乡一体化、城乡协调发展才是实现中国农村现代化的必由之路。     

情绪工作研究的理论综述

情绪工作是近20多年来西方组织行为学研究中一个新兴的研究领域。文章主要介绍了情绪工作的概念,情绪工作的维度与测量工具、情绪工作的影响因素,并进一步分析了情绪工作的未来研究趋向,以期为深入研究情绪工作提供理论基础。     

The examination of glass particles using the interference objective. Part 2: A survey of flat and curved surfaces

The microscopical examination of original surfaces on casework sized glass particles using an interference objective and the interpretation of their interferograms is discussed. To reduce subjectivity, a numerical criterion was devised to assess the curvature of glass particles and this was then applied to a survey of window, container, tableware and vehicle glasses. Objects with curved surfaces produced particles that were distinctly curved while those from surfaces of both modern and old windows were clearly identifiable as flat. Apparently flat surfaces from tableware and containers almost always yielded specimens that were detectably curved. In addition, there was no evidence that a fracture surface would be confused with an original surface from a plain flat glass.In a ‘blind’ trial to assess the interferometric routines, three examiners correctly identified flat and curved surfaces on 15 particles derived from a selection of glass objects.     

Windows Surface RT tablet forensics

Small scale digital device forensics is particularly critical as a result of the mobility of these devices, leading to closer proximity to crimes as they occur when compared to computers. The Windows Surface tablet is one such device, combining tablet mobility with familiar Microsoft Windows productivity tools. This research considers the acquisition and forensic analysis of the Windows Surface RT tablet. We discuss the artifacts of both the Windows RT operating system and third-party applications. The contribution of this research is to provide a road map for the digital forensic examination of Windows Surface RT tablets.     

Impinging blood droplets on different wettable surfaces: Impact phenomena,contact line motion,post-impact oscillation and dried stains

Understanding the underlying hydrodynamics of impinging blood droplets and finding out the physical parameters determining the bloodstain characteristics are of great importance in blood related forensic investigations. In this work, the impact of non-Newtonian blood droplets on solid surfaces ranging from lyophilic to superlyophobic was systematically investigated and compared to that of Newtonian droplets with a similar dynamic shear viscosity. We show that impinging blood droplets behave as low-viscosity Newtonian droplets in the short-time spreading, which is dominated by capillary and inertial forces, but their non-Newtonian viscoelasticity would notably affect the droplet retraction and post-impact oscillation occurring in large timescales. Whereas the strong liquid–solid adhesion and the non-Newtonian elongational viscosity hinder droplet recoiling and thus alter the impact phenomena on lyophobic and superlyophobic surfaces, the shear and elongational viscosities are coupled to result in higher damping coefficients of oscillating blood droplets after deposition, in comparison to that of impinging Newtonian droplets. The size of the dried bloodstain was found to be different from both the maximum spreading radius of the droplet that can reach during impact and the final radius of the deposited droplet after oscillation, and their correlations are highly dependent on the impact velocity and surface wettability. Moreover, the morphologic characteristics of the bloodstains would also be changed by varying either the impact velocity or the surface wettability. We envision that these findings can not only find applications in the bloodstain pattern analysis, but also provide useful information for medical diagnosis based on blood droplet test.     

论税权二元结构及其价值逻辑

目前学界关于税权概念存在着一些争拗,而税收债权论和社会契约论的引入和运用,有助于对税权内涵及其本质的深层解构。显然,税权作为国家税权力与纳税人税权利的统摄,并非仅仅是一种语义上的概括,而是税权力与税权利互为债权债务关系表里的必然,其主体不仅包括行使税权力的国家,还包括授权国家行使税权力的纳税人,而且始终以保障纳税人权利的良好实现为依归。本文试图运用税收债权债务论和社会契约论来分析税权的概念和内涵,澄清税权的外观结构与内在本质,进而揭示宪政语境下税权结构生成的价值逻辑。     

Fingermark visualisation on metal surfaces: An initial investigation of the influence of surface condition on process effectiveness

Fingermark recovery from metal surfaces is an area of operational interest, both from the association of metals with weapons used in violent crime and from the increasing incidence in metal theft. This paper reports a feasibility study into the effectiveness of a range of fingermark visualisation processes in developing fingermarks on clean metals (brass, bronze and stainless steel), and on the same metals after prolonged exposure to an outdoor environment. Scanning electron microscopy (SEM) was used to investigate how the surface type and condition could influence the development of fingermarks for each of the processes used. It was found that the behaviour observed varied between each of the processes (cyanoacrylate fuming, Lumicyano?, gun blueing and carbon-based powder suspension). In some cases the chemical composition of the surface affected the development of the mark more than the surface condition, and in other cases the reverse was true. The best performing processes differed according to the surface type and condition, with cyanoacrylate fuming processes working best on brass and bronze, and powder suspensions being better on stainless steel. These preliminary results reinforce the need to take into account both surface type and condition before selection of the most effective fingermark visualisation process and demonstrate the value of techniques such as SEM in developing a fundamental understanding of the interactions between fingermarks and surfaces.     

Trace Elemental Analysis of Titanium Dioxide Pigments and Automotive White Paint Fragments for Forensic Examination Using High‐Energy Synchrotron Radiation X‐Ray Fluorescence Spectrometry*

Abstract: High‐energy synchrotron radiation x‐ray fluorescence spectrometry (SR‐XRF) utilizing 116 keV x‐rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. High‐field strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO₂) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high‐energy SR‐XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.