钢丝钳与剪刀破坏客体的机理及痕迹特征辨析

一、“钳剪痕迹”概念质疑目前,多数工具痕迹学教材和论文在分析钢丝钳和剪刀破坏客体形成的痕迹时使用“钳剪痕迹”这一概念,指罪犯利用钳剪刃口施行剪切作用破坏客体时在接触部位出现的变形,其外延包括钢丝钳的钳切痕迹和剪刀的剪切痕迹;分析受力时对钳切与剪切过程均应用材料力学中剪切变形的理论和实用计算方法,认为刃口给承痕客体施加的力是大小相等、方向相反、作用线平行且相距很近的两个力,在此二力作用下承痕客体产生剪切痕迹,并应用了剪应力的计算公式:     

钳具加工花纹对钳剪线条痕迹的影响

笔者通过对钳剪工具在钳剪过程中与被钳剪客体相对划动形成的钳剪线条痕迹、加工花纹痕迹等形成过程的观察及机理的研究,进一步探讨加工花纹对线条状痕迹及加工花纹痕迹的影响。     

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。     

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…     

关于常见剪类工具及其痕迹的分析

对目前常见的几种剪类工具进行考察和分析,研究这些工具加工特征的形成及特点,从而进一步确定这些特征的特定性,并对其所形成的痕迹作出分析。找出根据现场痕迹进行工具种类推断和检验鉴定的方法。     

断线钳剪切链锁形成痕迹的研究

链锁是一种较为常见的安全防护锁具。破坏链锁实施盗窃犯罪,在侵财案件中较为常见。但当前对于断线钳剪切链锁形成的痕迹还缺少专门性的研究。因此,对于链锁剪切痕迹的研究、分析、利用,有其必要性。本文通过对其痕迹的研究,以期掌握此类痕迹的形成、变化规律,对推断工具种类,准确的进行同一认定具有重要意义。     

推断工具种类1例

钳剪形成的夹持痕迹,往往会出现对称的钳剪刃口痕迹或夹持面平台及齿纹痕迹,很少会同时出现夹持面后平台和钳剪刃口痕迹。笔者曾遇到一起夹持面     

钳剪断头印压痕迹的检验

本文通过工痕检验实践发现,在一些常见的钳类工具中,由于生产工艺的原因,使其结构上具有某种特定性,即在刃口两端有一条与刃口角度呈垂直的对称“结合条”(咬合条)。剪切客体时,会将部分对称结合条的印压痕迹遗留在被剪客体的断端,形成剪切印压痕。该痕迹的利用为一些不具备剪切比对条件的客体提供了认定的可能。     

论交通事故中的车体痕迹

交通事故司法鉴定中车体痕迹的鉴定至关重要,但目前对车体痕迹的概念、分类等尚见仁见智,存在一定差异,特别是对车体痕迹外部特征的表述,没有形成统一的标准。论文从车体痕迹的概念着手,分析了车体痕迹在司法鉴定中的应用,对广泛存在的车体痕迹从外部特征进行了详细分类,即附着物痕迹、移位痕迹、变形痕迹、刮擦刺剪痕迹、折叠痕迹、破裂破损爆裂痕迹、断脱脱落缺失痕迹、孔洞洞穿类痕迹、塌陷状痕迹、粉碎性痕迹等十种。希望引起讨论,形成统一的标准。     

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。     

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.     

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.     

印文鉴定相关问题探讨——高仿真印文鉴定

当前,与印文鉴定相关的并在鉴定实践中经常遇到的新问题和难点问题有高仿真印文的鉴定、变造印章问题、利用真实印文变造文件、同版印章印文、朱墨时序等,本文就高仿真印文的鉴定进行了系统阐述,介绍了各种高仿真印文,包括各种高仿真印章的盖印印文、复制印文、转印印文的伪造手段及其特点,并提出了高仿真印文的鉴定思路和要点。     

A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.     

Evaluation and comparison of the electrostatic dust print lifter and the electrostatic detection apparatus on the development of footwear impressions on paper

The Electrostatic Dust Print Lifter (EDPL) and the Electrostatic Detection Apparatus(2) (ESDA(2)) were compared to determine if both processes could be used to develop footwear impressions of the same or similar quality and in what order they should be used to develop the highest quality footwear impression. The sensitivity of each technique was also evaluated. The quality of the footwear impressions developed was determined by comparing 25 individual characteristics present on the known shoe to the footwear impressions developed using each technique. The footwear impressions were made by stepping on paper placed over several different surfaces, which included: linoleum, industrial Berber carpet, nylon carpet placed over a (3/8)-in. pad, ceramic tile, cardboard, 1-in. foam, 4-in. foam, cement, asphalt, grass, and mulch. Each of the papers placed on these surfaces was developed using the EDPL before the ESDA(2) and vice versa. The sensitivity test for the ESDA(2) was conducted by processing 10 sheets of stacked paper that were stepped on with the known shoe, beginning with the top sheet. The sensitivity test for the EDPL was conducted by processing 10 sheets of paper stepped on with the known shoe in succession. This study determined the footwear impressions developed using the EDPL were of better comparative value than impressions developed with the ESDA(2). On average, 72.4% of the individual characteristics from the known impression were identified on images developed when the EDPL was used first compared with an average of 38.9% when the ESDA(2) was used first. Therefore, if only one technique is used, the EDPL should be chosen. The sensitivity test determined the ESDA(2) develops high-quality footwear impressions on only the top sheet of paper. No footwear impressions were developed on any sheets under the top sheet of paper. The sensitivity test also determined the EDPL results increase in quality as the amount of dust residue decreases on the surface.     

同源性机雕渗透印章印文鉴别方法

目的寻找同源性机雕渗透印章印文间的特征差异,探索检验鉴定此类印章印文的方法。方法制作了9枚同源性机雕渗透印章并盖印大量的印文样本,通过文检仪、显微镜等仪器观察分析印文特征。结果找出了同源性机雕渗透印章印文间的细节特征差异。结论同源性机雕渗透印章虽规格性特征符合好,但仍旧可以区分,检验鉴定要以细节特征比对为主。     

Controlling the variable of pressure in the production of test footwear impressions

Footwear impression lifting and enhancement techniques may be affected by several variables introduced during the production of test footwear impressions, thus limiting the usefulness of enhancement technique comparisons and the results obtained. One such variable is the force applied when the impressed mark is being made. Producing consistent test impressions for research into footwear enhancement techniques would therefore be beneficial. This study was designed to control pressure in the production of test footwear impressions when mimicking a stamping action. Twenty-seven volunteers were asked to stamp on two different surfaces and the average stamping force was recorded. Information from the data obtained was used to design and build a mechanical device which could be calibrated to consistently deliver footwear impressions with the same force onto a receiving surface. Preliminary experiments using this device and different contaminants on the footwear sole have yielded consistent and repeatable impressions. Controlling the variable of pressure for the production of test impressions in this study demonstrated that the differences observed were visual (due to the amount of contaminant transferred and subsequent enhancement) and did not affect the replication of outer sole characteristics. This paper reports the development of the device and illustrates the quality of the impressions produced.     

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.     

对鞋内底足迹的研究与应用

刑事案件中对足迹的发现、提取、利用是很寻常的事,人们已习惯了运用各种检验技术对鞋外底遗留足迹特征检验、运用。而本文则是作者在总结实际办案的经验和教学研究的基础上,以鞋内底足迹为切入口,重点谈谈鞋内底足迹的概念、形成机理、特征及应用。     

Chemical enhancement of footwear impressions in blood on fabric — Part 2: Peroxidase reagents

This study investigates the optimisation of peroxidase based enhancement techniques for footwear impressions made in blood on various fabric surfaces. Four different haem reagents: leuco crystal violet (LCV), leuco malachite green (LMG), fluorescein and luminol were used to enhance the blood contaminated impressions.The enhancement techniques in this study were used successfully to enhance the impressions in blood on light coloured surfaces, however, only fluorescent and/or chemiluminescent techniques allowed visualisation on dark coloured fabrics, denim and leather. Luminol was the only technique to enhance footwear impressions made in blood on all the fabrics investigated in this study.