订书钉装订痕迹特征的研究

随着犯罪现场上遗留的常规痕迹的减少,非常规痕迹的发现和研究已极为必要。针对几种案件(如经济纠纷案、匿名控告案等)中用订书钉装订书写材料情况的出现,本文将就订书钉装订痕迹特征的稳定性、特定性,在理论和实验方面做初步探讨。 1 实验材料和样本收取 1.1 实验材料 (1)厂家不同、新旧不一的订书器10个。 (2)沈阳产“长鸣”牌订书钉2盒(1000个/盒),钉尖为垂直于钉体方向剪切的订书钉(订书钉钉尖分别为垂直、平行于钉体形式)。 (3)计算机打印纸若干张。     

订书钉上痕迹的检验及鉴定

订书钉作为一种装订材料,被订书机打入文件等纸张上起固定作用。在打入过程中,订书机刀片是否会在订书钉背面留下痕迹,以及留下的痕迹有无检验条件,可否利用上述痕迹进行订书机的同一认定等等问题,此前未见报道。本文从订书钉、订书机的生产、使用方面进行了实验分析。     

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。     

订书钉痕迹检验1例

1案情简介 2008年5月，广州铁路集团公司某站段发生多起投递匿名信扬言爆炸的案件。6月，专案组送来相关信件2封，为不同时间在不同地点投递，信件反映的内容也不同，要求检验2封信是否是同一人所为。初步检验，两封信的信封及内容均为激光打印机打印，其中信件1为订书钉装订的3页A4纸，信件2为订书钉装订的4页A4纸。由于无条件从指纹及打印机痕迹上作检验，通过对订书钉上印压痕迹的检验认定2信件上的订书钉为同一订书机所装订，为并案侦察提供了依据。     

硅胶仿生指纹膜印泥痕迹特征研究

目的研究硅胶仿生指纹膜印泥痕迹特征与真实指纹印泥痕迹特征的差异,为鉴定硅胶仿生指纹膜印泥痕迹提供依据。方法首先利用液态硅胶制作仿生指纹膜,然后用仿生指纹膜和手指在相同情况下蘸取印泥,分别以轻、中、重3种力度在A4纸上垂直按压形成印泥指印,并对其拍照提取,比较仿生指纹膜印泥痕迹与真实指纹印泥痕迹的特征差异。结果仿生指纹膜印泥痕迹多见“空白”“断裂”,边缘部分不规则、凹凸不平,小犁沟宽窄程度随力度变化明显,细节特征反映不清楚;真实指纹印泥痕迹自然、纹线较连贯。结论仿生指纹膜印泥痕迹特征与真实指纹印泥痕迹特征之间存在差异,根据两者之间的特征差异可以帮助鉴别仿生指纹膜印泥痕迹。     

内凹齿钥匙痕迹特征研究

目的运用光学仪器研究内凹齿钥匙痕迹形态特征。方法制作内凹齿钥匙正常开锁和被钥匙机复制后的样本,用光学显微镜拍照固定痕迹特征。结果内凹齿钥匙开锁痕迹特征明显,且被钥匙机复制后能留下复制痕迹。结论通过检验内凹齿钥匙上的痕迹特征能确定钥匙是否被复制过。     

3种常见皮革及其制品痕迹检验初探

为了扩大痕迹检验范围,笔者通过实验,对猪、羊、牛3种常见皮革及其制品的样本痕迹进行了观察研究,揭示了皮革痕迹的固有特征和皮革制品痕迹的特征。结果表明,利用上述特征,可对皮革制品痕迹进行同一认定检验。     

被伐树木整体分离痕迹检验中特殊特征和固有特征的运用

被伐树木形成的整体分离痕迹有其独特性,反映出特有的规律。本文介绍了在盗伐林木案件中,运用整体分离痕迹检验原理、方法,检验被伐树木分离面、分离缘的形态,检验其凸凹断茬特征、虫眼特征、裂纹特征、空心特征等特殊特征以及节子特征、年轮特征、木射线特征、树皮纹理特征等固有特征。特别是在两对应的锯断面之间木质完全缺失情况下,综合运用上述特征有针对性地检验,解决了部分被伐树木整体分离痕迹检验中分离痕迹能否作为同一认定证据、分离体是否原为同一整体的问题。文中所述对被伐树木上的特殊特征和固有特征的研究和运用,拓宽了被伐树木整体分离痕迹检验中特征标记的范围,为丰富被伐树木整体分离痕迹的检验方法提供了参考。     

猎枪射击弹壳上击针孔痕迹的变化及成因

1问题的提出猎枪属于民用非自动滑膛枪支,大多数使用12号规格猎枪弹。其射击弹壳击针痕迹位于弹壳底部中心,呈圆形,痕底呈球冠状,多为均匀圆滑,无明显的细节特征。但是在日常的枪弹痕迹检验当中,多会发现其射击弹壳击针孔痕迹中有时会出现圆形或椭圆形的突起状痕迹特征,我们俗称之为击针头的“假特征”(见图1)。这种痕迹特征与猎枪在使用过程中,在击针头产生的凹凸痕迹的细节特征明显不同;即使同一支猎枪所发射,在射击弹壳上击针孔痕迹也会产生变化。有的猎枪弹底会出现上述的痕迹特征,有的不出现(见图2);即使出现了该类痕迹,其痕迹特征亦不…     

几类常见钥匙被增配使用后在母匙上形成痕迹的检验方法

目的研究几类常见钥匙增配痕迹特征分布。方法用光学显微镜观察钥匙的增配痕迹。结果几类钥匙的增配痕迹能够观察到。结论通过检验不同种类钥匙上的痕迹特征可以确定是否为增配使用痕迹。     

内、外铣槽钥匙机械配制痕迹的研究

目的研究内、外铣槽钥匙机械配制后痕迹的出现规律及其影响因素。方法利用传统的痕迹检验方法观察痕迹出现的位置、形态及分布规律。结果内、外铣槽钥匙机械配制后会留下不同于其原始加工痕迹和使用痕迹的增配痕迹，这种痕迹是否明显出现、出现的形态和位置受钥匙材质和结构、配匙机、配匙人员工作经验等因素的影响。结论当未发现内、外铣槽钥匙上有明显增配痕迹时，不能轻易做出钥匙未被增配的判断。     

Identification properties of the office binding machine

The office binding machine is designed to punch a series of rectangular shaped holes along the edge of paper stock. These holes facilitate insertion of a plastic ring to bind the pages into a notebook.Research was conducted to determine if punched holes in paper could be identified as the work of a particular binding machine. Alignment, spacing and imperfections along the edges of the punch marks were considered.It was concluded that in some instances it is possible to identify the product of a binding operation with the punching machine.     

Restoration of engraved marks on steel surfaces by etching technique

It is known that restoration of erased engraved identification marks on the engine and the chassis of a car or on a firearm has low success rate. Unlike stamping, engraving on a metal surface leaves no pronounced, permanent subsurface deformation in the crystalline structure, also called dislocation that can be revealed by suitable methods. Hence, the current research work investigated whether metallographic reagents used in the restoration of stamp (compression) marks could be applied to recover engraved marks on steel surfaces and also to establish the sensitivity and effectiveness of some of these reagents for the restoration of the marks. Experiments were conducted by mechanically engraving alphanumeric characters on several steel plates using a computer controlled engraving machine called Gravograph. The markings were later erased from the above steel plates by removing the metal in stages of 0.01 mm through 0.04 mm below the bottom of the engraving. Several plates were thus prepared wherein each one had been abraded to a specific depth. Then eight metallographic reagents were tested on each one of the above erased plates using a swabbing technique. The results had shown that while most of the reagents were able to restore marks up to certain levels of erasure, the reagent 5 g copper sulphate, 60 ml water, 30 ml concentrated ammonium hydroxide and 60 ml concentrated hydrochloric acid restored marks erased to a depth of 0.04 mm below the engraving depth, thus presenting itself the most sensitive reagent. Quite significantly, the above reagent was also able to decipher successfully the original engraved marks that had been erased and engraved with a new number, or obliterated by centre punching. The results of this research work should benefit the forensic practitioners engaged in the serial number recovery on vehicles, firearms and other objects.     

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.     

方形坡状齿钥匙增配痕迹的实验研究

目的探索方形坡状齿钥匙增配痕迹形成规律、增配痕迹随开启次数的渐变过程以及增配痕迹的变化因素。方法用被增配过的原配钥匙和增配钥匙进行模拟开启实验，观察并记录开启前和开启过程中的增配痕迹。结果被增配钥匙的坡面上有明显的印压痕迹和擦划痕迹，增配痕迹随开启次数增加呈渐变性变化，且原配钥匙和增配钥匙上的增配痕迹变化不同。结论增配痕迹为印压痕迹和擦划痕迹，印压痕迹随着开启次数增加而逐渐消失，擦划痕迹较稳定。     

Examination of spur marks found on inkjet-printed documents

In this paper, we propose the examination of spur mark evidence on inkjet-printed documents. Spur marks are tool marks created by the spur gears in the paper conveyance system of many inkjet printers. The relationship between printouts and printers were investigated by comparing the spur marks found on printed documents with reference spur marks sampled from known printers. The comparison was based on two characteristics of spur marks: pitch and mutual distance. These characteristics extracted the geometric features of spur marks and provided information on the type of spur gears and their location in the paper conveyance system. The spur marks on a printout matched the reference spur marks within three percent of the measured values. Spur marks were considered to be effective class characteristics to identify certain brands of inkjet printers since spur gears are used in many types of these machines.     

Unusual chamber marks on plastic shells

Chamber marks alone can serve for identification. It has been observed that these marks are more clearly imprinted on plastic shells fired through homemade crude weapons. The importance of these marks is crucial when other conventional marks are absent. In the present communication, principles of identification are briefly discussed along with the factors affecting the conventional marks. One such actual case is cited.     

用羊角锤撬压形成线形痕迹的检验

目的介绍羊角锤起钉槽撬压形成擦划痕迹的检验方法。方法痕迹整体分析及特征接合。结果具备同一认定条件。结论通过了解羊角锤的结构特点和功能,综合分析撬压时形成痕迹的作用关系,按照现场环境条件制作样本,可以进行同一认定。     

通过痕迹认定肇事车辆

随着交通事故勘验技术的发展,物证技术在重特大交通事故现场勘验以及侦破交通逃逸案件中发挥的作用越来越重要.痕迹检验技术作为物证技术的一个重要分支,在认定肇事车辆中发挥着举足轻重的作用.交通事故中的痕迹是车辆与车辆、人体、道路等客体在路面上相对高速运动形成的痕迹,相对于其它类型案件有着自己的特点.交通事故中的痕迹分布范围广、造痕体和承痕体相对运动剧烈,形成痕迹的造痕体和承痕体大多都会发生形变.基于交通事故中痕迹形成的这些特点,交通事故中的痕迹检验难度是比较大的.但交通事故中车辆的特殊结构形成的印压痕迹、车辆轮胎、摩托车车篮等造痕体在灰尘等介质作用下在人体的衣服等表面形成的印压痕迹都可以很好反映造痕体的外部结构特征,从这些痕迹反映出造痕体的外部结构特征可以寻找和认定交通肇事车辆.