Portable high‐resolution automated 3D imaging for footwear and tire impression capture

The forensic science community raised the need for improved evidence recognition, collection, and visualization analytical instrumentation for field and laboratory use. While the 3D optical techniques for imaging static objects have been extensively studied, there is still a major gap between current knowledge and collecting high‐quality footwear and tire impression evidence. Among optical means for 3D imaging, digital fringe projection (DFP) techniques reconstruct 3D shape from phase information, achieving camera‐pixel spatial resolution. This paper presents a high‐resolution 3D imaging technology using DFP techniques dedicated to footwear and tire impression capture. We developed fully automated software algorithms and a graphical user interface (GUI) that allow anyone without training to operate for high‐quality 3D data capture. We performed accuracy evaluations and comparisons comparing with the commercial high‐end 3D scanner and carried out qualitative tests for various impressions comparing with the current practices. Overall, our technology achieves similar levels of accuracy and resolution with a high‐end commercially available 3D scanner, while having the merits of being (1) more affordable; (2) much easier to operate; and (3) more robust. Compared with the current practice of casting, our technology demonstrates its superiority because it (1) is non‐destructive; (2) collects more evidence detail than casts, especially when an impression is fragile; (3) requires less time and money to collect each piece of evidence; and (4) results in a digital file that can easily be shared with other examiners.     

金触危机下美国对华贸易保护与中国政府的应对策略——以＂轮胎特保案＂为视角

金融危机导致国际贸易萎缩,继而加剧国际市场竞争,也促使各国采取更为保守的贸易政策和措施,从而加剧国际贸易摩擦。最近发生的轮胎特保案就是由于美国奉行贸易保护政策的典型实例。美国的贸易限制对中国经济的影响非常大,不仅直接影响到中国众多企业的生存发展,而且会对中国整个经济发展带来冲击。如何应对美国对华实施的贸易保护政策已经成为一项非常复杂而又十分紧迫的任务,这其中,政府的引导和协调起着不可替代的主导作用。     

交通事故中轮胎爆破痕迹的检验与应用

车辆轮胎爆破在交通事故中较为常见,对爆胎痕迹进行检验和鉴定,弄清爆胎原因,在查明事故真相和责任认定中起着至关重要的作用。由于爆胎痕迹形成机理和原因复杂,检验鉴定的难度较大。通过对各类爆胎痕迹的形态特征及其差异的讨论,提出了交通事故中爆胎痕迹的检验要点。     

转型期农村基层治理变革之宪政精神

经济社会转型期随着市场化发展而日渐觉醒的村民的民主意识、法治理念、权利思维、平等观念的不断增强,使得村民以前所未有的热情关注和参与农村社会政治事务,农村现有的基层治理模式和乡村民主政治体制面临着变革和调整的重任。宪政作为人类政治文明的产物,代表着政治现代化的发展路径。宪政应当是中国农村基层治理变革的方向,基层治理的创新和变革具有鲜明的宪政内涵和宪政特性。基层的治理变革既需要对农村基层社会的经济政治资源进行调整和组合,更需要在宪政理念的主导下进行自治制度的革新。基层治理的宪政化建设是农村经济社会转型期基层治理变革的方向。在宪政理念的指引下,农村基层治理变革具有独特的宪政路径和明确的宪政精神。     

The analysis of tire rubber traces collected after braking incidents using Pyrolysis-GasChromatography/Mass Spectrometry

Automobile tire marks can routinely be found at the scenes of crime, particularly hit-and-run accidents and are left on road surfaces because of sudden braking or the wheels spinning. The tire marks are left due to the friction between the tire rubber and the solid road surface, and do not always demonstrate the tire tread pattern. However, the tire mark will contain traces of the tire. In this study, Pyrolysis Gas Chromatography/Mass Spectrometry was used to analyze 12 tires from different manufacturer's and their traces collected after braking incidents. Tire marks were left on a conglomerate road surface with sudden braking. The samples were pyrolysed without removal of contaminant in a micro-furnace type pyrolyser. Quantitative and qualitative analysis were performed on all the samples. All 12 samples were distinguished from each other. Each of the tire traces were identified as coming from there original source.     

裂解气相色谱-质谱法和热失重法检验轮胎胎面胶成分

目的 建立一种轮胎胎面胶提取物检验分析方法.方法 用热失重法（TGA）和裂解气相色谱-质谱法（PGC-MS）,测试了常见的10种轮胎胎面胶提取物的成分及含量.结果 该方法可以鉴别不同轮胎胎面胶提取物的种类,同时可以推断出胎面胶遗留物的含胶率,油及增塑剂、灰分、炭黑的含量;不同品牌轮胎胎面胶提取物的热失重行为也存在较大差异.结论 该方法能为肇事车辆轮胎的溯源及认定提供技术支持.     

交通事故轮胎鉴定概述

轮胎鉴定是指涉及事故车辆的轮胎相关的鉴定项目,是交通事故技术鉴定中的重要项目之一,一般可分为轮胎痕迹鉴定和轮胎损坏情况及其与事故关系鉴定两种.本文着重论述了交通事故技术鉴定中上述两种轮胎鉴定的定义、鉴定步骤、鉴定方法,并通过典型案例来全面解读轮胎鉴定的具体鉴定过程.     

Forensic applications of infrared imaging for the detection and recording of latent evidence

We report on a simple method to record infrared (IR) reflected images in a forensic science context. Light sources using ultraviolet light have been used previously in the detection of latent prints, but the use of infrared light has been subjected to less investigation. IR light sources were used to search for latent evidence and the images were captured by either video or using a digital camera with a CCD array sensitive to IR wavelength. Bloodstains invisible to the eye, inks, tire prints, gunshot residue, and charred document on dark background are selected as typical matters that may be identified during a forensic investigation. All the evidence types could be detected and identified using a range of photographic techniques. In this study, a one in eight times dilution of blood could be detected on 10 different samples of black cloth. When using 81 black writing inks, the observation rates were 95%, 88% and 42% for permanent markers, fountain pens and ball-point pens, respectively, on the three kinds of dark cloth. The black particles of gunshot residue scattering around the entrance hole under IR light were still observed at a distance of 60 cm from three different shooting ranges. A requirement of IR reflectivity is that there is a contrast between the latent evidence and the background. In the absence of this contrast no latent image will be detected, which is similar to all light sources. The use of a video camera allows the recording of images either at a scene or in the laboratory. This report highlights and demonstrates the robustness of IR to detect and record the presence of latent evidence.     

利用热重法鉴别汽车轮胎橡胶

目的建立热重法对汽车轮胎橡胶进行鉴定的方法。方法应用热重法对12种轮胎橡胶样品进行分析。结果分别获得了12种轮胎橡胶的TG及DTG曲线和它们在三个阶段的失重百分率、DTG的峰温。结论可以方便地鉴别组成不同或牌号不同的轮胎橡胶制品,为划定与缩小嫌疑车辆的范围和认定肇事车辆提供依据。     

Friction Marks of Stabbing Tools in Tires

When receiving a stabbed tire for examination, forensic toolmark examiners can determine whether a suspect tool was used in a specific crime based on class-characteristics and individual-characteristics marks that have been left by the tool on the tire. This study discusses friction marks and their forensic value during the examination of a punctured tire. The term friction mark refers to the noticeable mark around the penetration area on a tire's surface. Tires designed to create high friction when contacting a road. Due to this design, friction is created between the stabbing tool shank and the sides of the hole. As a result of this friction, the shank of the stabbing tool wears the outer layer of tire around the hole. This leaves a friction mark whose general shape reflects the cross-sectional shape of the stabbing tool’s shank. This phenomenon was observed and named by Locke (7) in his evaluation of tire puncture marks with knives. This article demonstrates the same phenomenon with other types of stabbing tools. Test stabs were produced with different tools representing a variety of cross-sectional shapes of shanks, and the resulting friction marks were photo-documented and discussed. Correlations between the various cross-sectional shapes and their corresponding friction marks are shown. Based on friction mark examination, the examiner: (i) can infer suspect tool shank cross-sectional shape with the evaluation of the friction mark shape and (ii) can deduce the maximum dimensions of the shank. This examination simplifies and accelerates the forensic comparison procedure and the investigation time.