Classification and individualization of black ballpoint pen inks using principal component analysis of UV-vis absorption spectra

The technique of principal component analysis has been applied to the UV-vis spectra of inks obtained from a wide range of black ballpoint pens available in the UK market. Both the pen ink and material extracted from the ink line on paper have been examined. Here, principal component analysis characterised each spectrum within a group through the numerical loadings attached to the first few principal components. Analysis of the spectra from multiple measurements on the same brand of pen showed excellent reproducibility and clear discrimination between inks that was supported by statistical analysis. Indeed it was possible to discriminate between the pen ink and the ink line from all brands examined in this way, suggesting that the solvent extraction process may have an influence on these results. For the complete set of 25 pens, interpretation of the loadings for the first few principal components showed that both the pen inks and the extracted ink lines may be classified in an objective manner and in agreement with the results of parallel thin layer chromatography studies. Within each class almost all inks could be individualised. Further work has shown that principal component analysis may be used to identify a particular ink from a database of reference UV-vis spectra and a strategy for developing this approach is suggested.     

The changes of fourier transform infrared spectrum in rat brain

Estimation of the time since death (postmortem interval [PMI]) is one of the most difficult problems in forensic investigations, and many methods currently are utilized to estimate the PMI. The goal of this study was to investigate the changes of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra of rat brain from postmortem time 0-144 h. The intensity ratios of major absorbance bands were examined (I(1066)/I(1392), I(1168)/I(1392), I(1234)/I(1454), I(1301)/I(1392), I(1647)/I(2956), I(2921)/I(2850), and I(1647)/I(1539)). The spectra of rat brain displayed prominent changes with increasing PMI. The band at 2871 and 1737 per cm became weak with the time increasing and even disappeared at postmortem 96 and 72 h, respectively. A close linear correlation was shown between the relative absorption intensity and the PMI, and the I(1234) /I(1454) offered a stronger correlation (r = 0.973). Our results indicate that ATR-FTIR spectroscopy may be a useful technique for estimating the PMI.     

拉曼光谱成像技术检验朱文时序时印文油墨种类对检验结果的影响

目的考察在运用拉曼光谱阵列面扫描检验朱文时序的方法中印文油墨种类对检验结果的影响。方法根据拉曼谱图的不同对搜集的21种印泥印油进行扫描并分类,采用拉曼光谱阵列面扫描技术对印泥印油与同一书写笔形成的朱文时序样本进行检验。结果 21种印泥印油被分为11类,21种印泥印油与蓝色签字笔形成的朱文时序样本都得到了良好的检验结果。结论印文油墨种类用拉曼光谱阵列面扫描检验朱文时序的检验结果没有影响。     

Visualizing latent fingerprints on color-printed papers using ultraviolet fluorescence

Laser detection of latent fingerprints on a white paper has been performed, previously. Ultraviolet fluorescence from various kinds of printer toner and ink used for home printers were measured to study fluorescence imaging of fingerprints on a color-printed white paper. The experimental system consisted of a nanosecond pulsed tunable laser and a cooled CCD camera. Excitation wavelengths are 230 and 280 nm. Fourteen printers consisting of three color laser printers, three color inkjet printers, five monochrome laser printers, two monochrome copy machines, and a color copy machine were tested. Toner and ink of most printers exhibited fluorescence in the region from 360 to 550 nm. In most cases, clear fluorescence images were obtained by time-resolved imaging with a band-pass filter and 280-nm excitation. However for toners from laser color printers that showed strong fluorescence, better results were obtained with 230-nm excitation. Latent fingerprints on a photograph page and a black-character page of a newspaper were also imaged.     

FTA战略下我国海外能源投资的法律问题研究——以我国投资澳洲能源为例

解决好海外能源投资中出现的法律问题是我国海外能源投资顺利进行的主要保障。海外能源投资出现的法律问题实质上涉及到资本输出国的相关完善的立法以及对于东道国相关外资法律规定的应对。据此对于如何完善我国资本输出的相关立法以及应对发达的东道国的外资法进行抛砖引玉的研究。     

Examining fatal and nonfatal incidents involving the TASER

Research Summary According to TASER International, nearly 10,000 police departments in the United States have deployed the TASER as a less lethal force alternative in some capacity. Despite the TASER's increasing popularity, serious questions have been raised about the device's physiological side effects; in particular, Amnesty International has reported that more than 300 people have died after being subjected to the TASER. Although a growing body of research has examined the physiological effects of the TASER on animals and healthy human volunteers in laboratory settings, there has been virtually no empirical analysis of “real‐world” fatal and nonfatal TASER cases simultaneously. This article examines all media reports of TASER incidents from 2002 to 2006 through a comprehensive review of LexisNexis and New York Times archives. We compare TASER incidents in which a fatality occurred to TASER incidents in which a fatality did not occur and then employ multivariate analyses to identify the incident and suspect characteristics that are predictive of articles describing TASER‐proximate deaths. Policy Implications Several suspect factors were significantly associated with the reporting of a fatal TASER incident, including drug use (but not alcohol), mental illness, and continued resistance. Multiple deployments of the TASER against a suspect was also associated with the likelihood of the article describing a fatality—especially if the suspect was emotionally disturbed—which raises the possibility that the risk of multiple shocks might not be uniform for all suspects. More research is needed to explore the relationship between mental illness, drug use (illicit or therapeutic), continued resistance, and increased risk of death. In the meantime, police departments should develop specific policies and training governing the use of multiple TASER shocks against individuals who could be in these vulnerable physiological and psychological states.     

车辆碰撞护栏事故车速分析的方法

车辆碰撞护栏是高速公路上常见的一类事故,主要有两种常用的车速分析方法,即法向弹性恢复系数法和切向摩擦系数法。但是由于高速公路上,车速较快,经常有车辆冲出道路,在此情况下,提出一种基于护栏变形能量的车速分析方法,用来计算车辆碰撞护栏时的最低速度,并通过实例进行了验证。     

Distributed Generation of Electricity: The Role of Academic Research and Advice in California’s “Clean DG” Policy Network

Deregulation and the combined threats of energy crises and global warming concern nations around the world, yet these issues continue to be addressed more directly by domestic regulatory systems than by international institutions. The present analyses of the integration of distributed sources of power generation (DG) into California’s electric utility system suggests that domestic environmental dilemmas with international repercussions provide an obvious entrée for global environmental policy specialists into the practice of environmental policy-making and law. Here I review current scholarship on policy networks that illuminates the contributions that technical and policy experts can make to such networks surrounding environmental issues. I then introduce the key members of California’s “clean DG” policy network that emphasizes the role of academic experts in this influential political system, and discuss how my own research has impacted the development of the state’s DG policy. I conclude that scholars are well positioned to observe and engage domestic and international environmental policy networks, and thereby also to influence environmental politics and law.     

社会活力问题研究

考察社会活力一般会涉及三个基本要素,即经济要素、社会制度要素和精神文化要素。社会活力有两个来源:一是根本来源,二是直接来源。社会活力的根本来源源于生产力和生产关系之间关系的合理性。直接来源源于社会制度的先进性、社会运行体制的合理性、社会运行机制的多样性。激发社会活力是社会主义制度的特征之一,充分体现了社会主义制度的根本属性。     

Morphological and spectroscopic measurements of plastic bags for the purpose of discrimination

The discrimination of noncolored transparent polyethylene bags was studied by several nondestructive and semidestructive analytical methods. X-ray diffraction, infrared spectroscopy, and optical microscopy (differential interference contrast microscopy and phase contrast microscopy) were applied to polyethylene films. X-ray diffraction was used to distinguish variations in the crystalline phase, infrared spectroscopy was used to distinguish variations in the molecular components, and optical microscopy was used to distinguish the different surface morphologies. The results show that X-ray diffraction classifies the crystalline phase of the film depending on whether it is made from low-density polyethylene, linear low-density polyethylene, or high-density polyethylene; that infrared spectroscopy is useful to distinguish the molecular components and it is the most discriminating technique; and that optical microscopy discriminate films easily by their morphological differences.