几种新型手枪射击弹壳上痕迹特征浅析

为了适应新形势下枪弹检验工作的需要,我中心枪弹处于1997、1998年分别购置了一批新型枪支.其中有13种配用9mm×19mm巴拉贝鲁姆手枪弹的新型手枪,它们分别是213型9毫米手枪、213A型9毫米手枪、七七B型9毫米手枪、七七B2型9毫米手枪、NP20型9毫米手枪、NP22型9毫米手枪、NP28型9毫米手枪、NP38型9毫米手枪、201C型9毫米手枪和NZ75型9毫米手枪.为了让更多的同行了解这13种新型手枪发射子弹的弹壳上的主要痕迹特征,我们制作了一些样本.由于每种枪仅购置了一支,故本文所介绍的有些痕迹特征究竟属于种类特征,抑或是个别特征,还有待于作进一步的实验和研究.将13种枪支划分为5组分别进行论述:一组:213型、213A型;     

A comparative research of two lifting methods: electrostatic lifter and gelatin lifter

Two-dimensional dust shoeprints are often of very high resolution and contain unique features. Lifting these prints in the most effective method may contribute much to preserving these fine details. A research was conducted by experts from Israel and Switzerland to compare gelatin lifters and electrostatic lifters for lifting shoeprints. Several substrates were chosen, and on each material a set of dry dust shoeprints was made. A set of wet prints was made on paper as well. The shoeprints were approximately of the same quality, and the only variable was the nature of the material. On substrates indifferent to the method used, the preferable sequence was tested. Gelatin lifter was superior on most substrates and for wet prints. The superior sequence for using both methods is electrostatic lifting followed by gelatin lifter.     

德国城市轨道交通概述——德国考察观感

介绍了德国城市轨道交通系统、售检票系统、德国交通以人为本的原则以及德国人的时间观念.     

立体轮胎痕迹的数码照相提取

立体轮胎花纹多发现于各类案件现场,它可为寻找、认定涉案车辆提供重要线索和依据。通常对立体轮胎花纹往往采用制模法提取其特征,而照相法尽用于平面轮胎痕迹的提取。对一些立体轮胎印痕也可以采用已广泛应用于平面痕迹提取的数码摄相法进行提取,并进一步采用图像处理软件对其特征进行加强。实验表明:数码照相能反映轮胎痕迹的一部分重要特征,通过软件处理这些痕迹特征得到加强。     

Comparison of Dimensional Accuracies Using Two Elastomeric Impression Materials in Casting Three‐dimensional Tool Marks

The purpose of this study was to evaluate two types of impression materials which were frequently used for casting three‐dimensional tool marks in China, namely (i) dental impression material and (ii) special elastomeric impression material for tool mark casting. The two different elastomeric impression materials were compared under equal conditions. The parameters measured were dimensional accuracies, the number of air bubbles, the ease of use, and the sharpness and quality of the individual characteristics present on casts. The results showed that dental impression material had the advantage of special elastomeric impression material in casting tool marks in crime scenes; hence, it combined ease of use, dimensional accuracy, sharpness and high quality.     

Classification of firing pin impressions using HOG-SVM

Crimes, such as robbery and murder, often involve firearms. In order to assist with the investigation into the crime, firearm examiners are asked to determine whether cartridge cases found at a crime scene had been fired from a suspect's firearm. This examination is based on a comparison of the marks left on the surfaces of cartridge cases. Firing pin impressions can be one of the most commonly used of these marks. In this study, a total of nine Ruger model 10/22 semiautomatic rifles were used. Fifty cartridges were fired from each rifle. The cartridge cases were collected, and each firing pin impression was then cast and photographed using a comparison microscope. In this paper, we will describe how one may use a computer vision algorithm, the Histogram of Orientated Gradient (HOG), and a machine learning method, Support Vector Machines (SVMs), to classify images of firing pin impressions. Our method achieved a reasonably high accuracy at 93%. This can be used to associate a firearm with a cartridge case recovered from a scene. We also compared our method with other feature extraction algorithms. The comparison results showed that the HOG-SVM method had the highest performance in this classification task.     

根据印文特征分析印章的材质与制作方法

在文件检验实际鉴定工作中发现,印文特征的形成既与制作方法有关又与印章的材质有关。如果能够通过印文特征确定其检材印文与样本印文是两种不同方法刻制或使用不同材质的印章所盖印,就不难做出正确的鉴定结论。通过分析印文特征的成因,可以确定其所盖印文的印章材质及其制作方法,进而识别印文的真伪。     

Note on fabric marks in motor vehicle collisions

Two cases are described where motor vehicle accidents lead to fabric weave impressions and fibres being transferred to the paintwork of vehicles from the clothes of the victims.     

印油与印油印迹比对检验方法的影响因素研究

目的针对印油印迹形成过程中可能存在的影响因素,研究印油与印油印迹比对分析方法中可能存在的风险。方法采用溶剂提取,高速离心,过膜的简单的前处理方法,然后高效液相色谱分析,用色谱峰峰面积的相对含量来判定印油印迹与印油之间的差异。结论印泥印油、印油印迹与印油之间差异很小;而印台印油、渗透印油、翻转印油、印油与印油印迹比对时,存在一定影响。     

自含墨印章印文盖印时间受老化条件的影响

目的探索利用气相色谱法较精确、定量测定自含墨印章印文盖印时间受人为老化条件的影响。方法分别在恒温烘烤、紫外线照射、纯水浸泡等人为老化条件下,测定自含墨印章印油中所含有的主要相关溶剂成份的含量变化。结果得出了主要溶剂成份在人为老化条件下其含量的变化规律以及人为老化与自然老化的对应关系。结论利用气相色谱法可以对不同保存条件下自含墨印章印文的盖印时间进行测定,为实际相关案件的检验提供了依据。