液压断线钳与普通断线钳剪切痕迹的检验及应用

目的通过研究不同类型、规格和功能断线钳所形成剪切痕迹的异同,准确的进行工具痕迹的同一认定。方法运用实验观察法,比较法对液压断线钳与普通断线钳形成痕迹特征反映的异同进行分析。结果液压断线钳与普通断线钳从结构特征、剪切痕迹特征反映等方面存在着明显的差异。结论在对剪切痕迹的检验中,需要注意从被剪断头的材质、直径、断端形状等方面着手,区别不同种类的剪切工具,尤其要注重对实验样本的制作,这样才能充分发挥剪切痕迹在侦查破案中的证据作用。     

从剪切痕迹区别钢丝钳种类

对不同产地的八个品牌钢丝钳的外刃侧加工花纹特征及其在剪切痕迹中的反映作了研究.总结出了各品牌钢丝钳特征的差异,达到了区分的目的.为钢丝钳种类推断提供了一种确实可行的方法.     

关于钢丝钳刃侧铣纹作为特征价值的研究

通过随机抽样统计方法,对钢丝钳及其痕迹进行观察,总结了刃侧铣纹的特定性规律。     

不同类型线缆剪剪切痕迹的区别

目的　研究三种类型线缆剪剪切线缆的痕迹差异 ;　方法　观察、归纳三种线缆剪形痕的宏观、微观痕迹反映形态 ;　结论　可以根据断头的整体形态、线条流向、弧度、立顶形态和顿剪痕迹等来分析线缆剪的种类。     

单芯电缆线断头痕迹实物提取方法

目的研究单芯电缆线这种离散型客体的实物提取方式、涉及的提取工具和最佳提取长度。方法采用模拟实验的方式,选用不同种类的单芯电缆线为客体,以电缆线断头痕迹不发生变化为基准,确定不同实物提取方式或不同种类工具提取单芯电缆线的最短长度。结果单芯电缆线实物提取可采取的方式主要有钳剪和割削两种,其中钳剪提取方式使用的工具为断线钳和线缆剪,割削提取方式使用的工具为钢锯和角磨机;针对直径小于16mm、非金属外护套及绝缘层的单芯电缆线,断线钳剪切提取最佳长度约为55cm,线缆剪剪切提取最佳长度约为70cm,钢锯锯割提取最佳长度约为5cm,角磨机切削提取最佳长度约为5cm。结论割削提取方法是提取电缆线断头的最佳方法;依据提取操作简便性及快捷性,角磨机(或充电式角磨机)为现场提取电缆线断头的最佳工具。     

钢丝钳夹持面痕迹形成特点与检验

在犯罪现场特别是盗窃现场和破坏通讯线路、通讯电缆等现场,经常有用钢丝钳作案后留下的痕迹。在不少文献中对钢丝钳的种类规格和钳剪痕迹的检验鉴定的论述。但对钢丝钳其它部位留下痕迹的检验报道较少,本文着重讨论钢丝钳夹持面痕迹形成的特点与检验。1钢丝钳夹持面的一般特点钢丝钳夹持面,是指从钢丝钳钳嘴起到夹圆体口止的部位。夹持面包括:钳嘴、前平台齿纹和后平台(有些厂家生产的钢丝钳无后平台)3个部分组成。夹持面因规格大小和生产厂家不同,在齿数、齿距、前后平台的宽度,钳嘴长度也不同。常见的几种规格钢丝钳夹持面的齿纹数,一般…     

后配钥匙的检验及鉴别

后配钥匙是借助于手工或机械锉、铣加工复制,齿列关系与原配钥匙相一致的新钥匙。而对用后配钥匙做案案例的研究,往往偏重于后配钥匙在锁芯弹子上形成的痕迹和原配钥匙在复制过程中形成痕迹的分析、研究,最能反映加工复制痕迹的后配钥匙常常被忽视。对其进行科学地分析和检验、识别原配或后配钥匙,这在实践工作中具有很大的应用价值。 1 后配钥匙上复制加工痕迹及其形成机理 后配钥匙一般是使用匙坯加工复制而成的,开齿过程中在钥匙坯上会形成明显的加工痕迹。后配钥匙上的加工痕迹主要有以下5种。     

不同工具打击玻璃的痕迹特点

用不同工具打击同种玻璃形成的痕迹不仅特征有差异，且辐射纹、同心纹等特征的分布形状也各不相同（见图1～5）。     

枪弹痕迹情报网络共享与交换

枪弹痕迹的远程会商,是利用计算机网络基础设施,采用多种网络多媒体技术,集中枪弹痕迹同一认定所需要的特征参数及有关资料,约请专家在网络上进行商讨,就某一案件枪弹痕迹同一认定,得出明确结论的一种新的工作方式。枪弹痕迹的远程会商能否实现,其很大程度取决于对枪弹痕迹鉴定本质的认识。为此,必须对枪弹痕迹的特征进行分类,并对每一类痕迹所能具备的鉴定价值属性进行确认。根据枪弹痕迹的形成机理、部位以及各特征层次的不同属性,可以确定主要将弹底痕迹特征中的击针头痕迹、后膛加工纹痕迹、抛壳挺痕迹作为枪弹痕迹远程会商系统工作的主…     

鞋内底浸渍痕迹的检验

1 鞋内底浸渍痕迹的形成 鞋内底浸渍痕迹是指鞋在穿用过程中，由于脚的蹬踩与汗液的浸渍，形成在鞋内底或鞋垫上的印痕。这种印痕与赤足足底具有对应性，在足迹检验中具有较高的利用价值。根据运动力学和生理学的原理，每个人的生理特点和运动能力的差异，形成的运动特征也各不相同，在鞋内底及鞋垫上会形成深浅、虚实不一的赤足形象特征，这就给我们的检验提供了有利的条件。     

利用铣纹痕迹数量和角度判断钢丝钳剪切位置

目的观察钳剪钢丝铣纹痕迹规律。方法用钢丝钳剪切铁丝,观察形成铣纹痕迹的特点和规律,并对铣纹痕迹数量和倾斜角度与钢丝钳剪切刃口位置的关系予以分析。结果钢丝钳刃口形成的铣纹痕迹数量和倾斜角度随刃口位置变动而发生相应变化。结论通过检测铣纹痕迹的数量和倾斜角度能可靠判断剪切刃口的具体位置,为制作样本选择刃口部位提供依据。     

Bolt Cutter Blade's Imprint in Toolmarks Examination

Bolt cutters are known as cutting tools which are used for cutting hard objects and materials, such as padlocks and bars. Bolt cutter blades leave their imprint on the cut objects. When receiving a cut object from a crime scene, forensic toolmarks examiners can determine whether the suspected cutting tool was used in a specific crime or not based on class characteristic marks and individual marks that the bolt cutter blades leave on the cut object. The paper presents preliminary results of a study on ten bolt cutters and suggests a quick preliminary examination—the comparison between the blade thickness and the width of the imprint left by the tool on the cut object. Based on the comparison result, if there is not a match, the examiner can eliminate the feasibility of the use of the suspected cutting tool in a specific crime. This examination simplifies and accelerates the comparison procedure.     

Identification of wires and the cutting tool by scanning electron microscope

The cut ends of aluminium and copper wires made by different pliers have been compared under the scanning electron microscope to correlate the two pieces of a wire and to identify the cutting tool. The mechanism of producing the cut ends has been discussed. Matching of extrusion marks and correspondence of breakages at the edges of the cut ends were observed. Correspondence between the fine striations was observed on the opposite faces. These features are put forward for assigning a cut wire to a source.The ends produced by repeatedly cutting a wire by the same portion of the edge of a pair of pliers have been compared. It was found that the striations and fracture zones were reproduced on the respective surfaces of the consecutive cut ends. To identify the cutting tool in wire theft cases, it is suggested that the trial cut ends can be made by cutting the wire with successive portions of the edge of the suspected tool and compare the surface features with that on the questioned ones.     

Quantitative Statistics and Identification of Tool‐Marks

This study was designed to establish a feature identification method of tool‐mark 2D data. A uniform local binary pattern histogram operator was developed to extract the tool‐mark features, and the random forest algorithm was adopted to identify these. The presented method was used to conduct five groups of experiments with a 2D dataset of known matched and nonmatched tool‐marks made by bolt clippers, cutting pliers, and screwdrivers. The experimental results show that the proposed method achieved a high rate of identification of the tool‐mark samples generated under identical conditions. The proposed method effectively overcomes the disadvantage of unstable illumination of 2D tool‐mark image data and avoids the difficulty in mark inspection caused by manually preset parameters in the existing methods, thus reducing the uncertainty of inspected results.     

钢丝表面线性痕迹的形成及检验

本文简要探讨了钢丝表面线性痕迹的形成机理、特定性、出现率以及相关痕迹的综合利用等问题.用案例说明钢丝表面线性痕迹检验鉴定的可行性和利用价值.     

断线钳剪切痕迹特征的实验研究

探讨断线钳剪切金属客体所形成的痕迹特征及其检验方法.     

An unusual case of high-voltage electrocution of a truck driver due to inadvertent contact of the truck with an overhead wire

Electrocution deaths are mostly accidental. However, reconstruction of events in unusual electrocution death is challenging. This article reports an accidental death due to electrocution in a highly unusual circumstance, in which a truck driver reversing his vehicle was electrocuted when his truck inadvertently touched an overhead high-voltage wire. The electric injury marks were present over the sole of the right foot. The scene investigation revealed that the high-voltage wire was loose and was below the level of the prescribed height. The truck was passing over an elevated area made up of dirt and stone. The interior of the cabin of the truck revealed a few non-insulated metallic areas over the floor of the truck, between the accelerator and the brake, which were attributed as the sources of entry of electricity into the body. The electric injury marks were different than those usually seen in high-voltage electrocution as there was an intermediate object (truck) involved, and the contact period between the truck and the electric wire was minimal. This fatality was attributed to the non-proper insulation of the interior of the truck, the negligent driving of the truck driver over the elevated surface, and the loose high-voltage wire without proper maintenance.     

Microscopic Analysis of Sharp Force Trauma in Bone and Cartilage: A Validation Study,,

Sharp force trauma research lacks agreement on reported error rates for correctly identifying toolmark characteristics on bone and cartilage. This study provides error rates for determining blade class (serrated, partially serrated, nonserrated) and type of edge bevel (left, right, even). Three analysts examined cuts to a wax medium, cartilage, and bone using two types of microscopes. Additionally, the observers examined impressions taken from the wax medium and the cartilage. Overall, a total of 504 observations were performed. Serrated blades were distinguishable from nonserrated blades due to their patterned striations. Some difficulties were encountered in distinguishing serrated and partially serrated blades; however, when these groups were considered together as one classification type (serrated), classification accuracy improved from 79% to 96%. Classification accuracy for edge bevel was 65%. Error rates were similar when comparing direct observation of the cut marks versus indirect observation (impressions). Additionally, the type of microscope used did not affect error rates.