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1.
打印复印文件朱墨时序表观特征初探 总被引:1,自引:0,他引:1
本文详细介绍了一案例的检验过程,并通过简单实验对激光打印、静电复印形成文件的朱墨时序的表观特征进行了粗浅的探究。总体而言,两种时序在朱墨交叉点的表观特征上具有文字与印文均完整、肉眼感觉文字均压在印文之上的共同点;在两者本质的差异点上,先朱后墨表现为交叉点的墨粉与未交叉部位一致,先墨后朱表现为交叉点的墨粉光泽度增加、具有潮湿感、以及易出现水珠状的印油积聚现象。 相似文献
2.
A Noninvasive and Speculative Method of Visualizing Latent Fingerprint Deposits on Thermal Paper 下载免费PDF全文
John W. Bond OBE 《Journal of forensic sciences》2015,60(4):1034-1039
Latent fingerprint deposits on thermal paper have been visualized noninvasively at visible wavelengths when illuminated with a UV‐A light source (peak 365 nm). A higher intensity UV source (250 W/m2 at 0.38 m) gave superior fingerprint visibility when compared with a 60 W/m2 (at 0.4 m) source. Removing the visible (blue) component of the light source emission did not adversely affect the visibility of the fingerprint. Sample fingerprints from 100 donors, when examined 24 h after deposition, produced identifiable fingerprints from nearly 34% of fingerprint deposits. A mechanism for the observed visibility is proposed based on low emission of visible wavelengths from areas of thermal paper coincident with the fingerprint deposit, when illuminated with UV. This is likely due to a weak color change in the thermal paper dye arising from protonated amino acid components of the sweat. This effect was not observed on nonthermal paper. 相似文献
3.
Response Assessment of Thermal Papers from Four Continents to Fingerprint Development by Heat 下载免费PDF全文
Latent fingerprint deposits on thermal paper sourced from the U.S., China, the U.K., and Australia have been visualized by heating. U.S. and Chinese sourced paper produced two distinct types of fingerprint development. In one type (type 1), the paper dye colors where the deposit is present (as previously reported) and in the other type (type 2) the ‘inverse’ of this gives paper coloring only in areas not coincident with the deposit. Both development types gave identifiable fingerprints, the majority fading within 24 h of heating. Fingerprint development from U.K. and Australian sourced paper was exclusively type 1 and resistant to fading. Temperatures for fingerprint visualization were higher for U.S. paper (64–71°C) and Chinese paper (75–95°C) than for U.K. and Australian sourced paper (43–50°C). Particularly for Chinese sourced paper, these temperatures were within a few degrees of the normal paper color temperature. A mechanism for type 2 fingerprint development is proposed. 相似文献
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Vincent Cuzuel M.S. Guillaume Cognon M.S. Isabelle Rivals Ph.D. Charles Sauleau M.S. François Heulard M.S. Didier Thiébaut Ph.D. Jérôme Vial Ph.D. 《Journal of forensic sciences》2017,62(2):330-350
Developing a strategy to characterize the odor prints of individuals should be relevant to support identification obtained using dogs in courts of justice. This article proposes an overview of the techniques used for the forensic profiling of human odor. After reviewing the origin of human odor—both genetic and physiological—the different analytical steps from sample collection to statistical data processing are presented. The first challenge is the collection of odor, whether by direct sampling with polymer patches, cotton gauze, etc., or indirect sampling with devices like Scent Transfer Unit. Then, analytical techniques are presented. Analyses are commonly performed with gas chromatography coupled with mass spectrometry. As they yield large amounts of data, advanced statistical tools are needed to provide efficient and reliable data processing, which is essential to give more probative value to information. 相似文献
6.
Bond JW 《Journal of forensic sciences》2011,56(4):999-1002
From an examination of the fingerprint sweat corrosion of 40 different individuals on α phase brass, we show that an increase in visualization can be achieved by applying a negative potential to the brass followed by the introduction of a conducting powder. Previously, this technique has been demonstrated only for a positive applied potential and a corrosion product that was dominated by p-type copper (I) oxide. X-ray photoelectron and Auger electron spectroscopic analyses of the surface of the corroded brass show that an increase in visualization with a negative applied potential corresponds with an increase in the concentration of n-type zinc oxide relative to p-type copper (I) oxide with the Cu:Zn ratio <0.8:1. Work function conditions for the formation of an n-type zinc oxide/brass rectifying Schottky barrier are fulfilled. 相似文献
7.
Through a comparison of fingermark sweat corrosion of α phase brass in both the U.K. and Iraq, we show how samples from Iraq have improved fingermark corrosion over U.K. samples that require no additional enhancement prior to visualization. Over 50% of Iraqi samples produced fingermark corrosion with full ridge detail compared with 0% from the U.K. X-ray photoelectron spectroscopy analysis of the fingermark corrosion products showed that Iraqi samples exhibit more dezincification with the Zn:Cu ratio averaging 1:1.82 compared with 1:3.07 for U.K. samples. Auger spectroscopy showed the presence of both zinc oxide and copper (I) oxide. No copper (II) was observed on the surface of the corroded brass. Opportunities to exploit the optical properties of these thin film oxides to enhance the visualization of fingermark corrosion are considered, and the potential to use fingermark corrosion of metal as a means of visualizing fingerprints in war zones is discussed. 相似文献
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Even though trace evidence is becoming more and more important in legal cases, only little is known about the influence of task and context factors on comparative judgments. In the present study we investigated how expectations and complexity affect shoe print examinations and to what extent differences exist between beginners and experienced examiners. Twelve examiners assessed similarity between a shoe print and a shoe for eight different cases. For half the cases expectation was induced by providing additional incriminating evidence. A complex case meant that the print was relatively noisy, for example because the perpetrator rotated his foot. A simple case meant that the print was clear. The results showed that there was no effect of expectation and no effect of experience. Only complexity affected the examiners' assessments: when the background was noisy, the acquired features received a lower evidential value than when the background was clear. Apparently, examiners compensated for the quality of the print and were more cautious in drawing conclusions when prints were less clear. Even though the results allow for some optimism with regard to the influence of expectations on shoe print examinations, it has to be taken into account that the Dutch procedure is supported by a formal guideline, which may (partly) explain the present findings. 相似文献
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Emma Paterson ; John W. Bond D.Phil. ; A. Robert Hillman D.Phil. 《Journal of forensic sciences》2010,55(1):221-224
Abstract: Effective removal of fingerprint deposits is crucial for experimentation related to the corrosion of metals by fingerprint deposits. Such removal is also necessary prior to deposition of test fingerprints. The effectiveness of four regimes in removing fingerprint deposits from brass is considered. Sustained wiping of the deposit with a tissue at applied pressures of up to c . 1430 Pa or rubbing while the brass was immersed in acetone both failed to remove completely all traces of fingerprint deposits. Heating the brass to 600°C was an effective remover; however, this also oxidized the surface of the metal except where inhibited by fingerprint deposits. The most effective regime, and the only one of the four that removed all traces of deposit without affecting the properties of the metal surface, was immersion in warm soapy water while rubbing with a tissue. We propose this as the preferred method for fingerprint removal. 相似文献
10.
Evaluation of Lip Prints on Different Supports Using a Batch Image Processing Algorithm and Image Superimposition 下载免费PDF全文
Lara Maria Herrera M.Sc. Clemente Maia da Silva Fernandes Ph.D. Mônica da Costa Serra Ph.D. 《Journal of forensic sciences》2018,63(1):122-129
This study aimed to develop and to assess an algorithm to facilitate lip print visualization, and to digitally analyze lip prints on different supports, by superimposition. It also aimed to classify lip prints according to sex. A batch image processing algorithm was developed, which facilitated the identification and extraction of information about lip grooves. However, it performed better for lip print images with a uniform background. Paper and glass slab allowed more correct identifications than glass and the both sides of compact disks. There was no significant difference between the type of support and the amount of matching structures located in the middle area of the lower lip. There was no evidence of association between types of lip grooves and sex. Lip groove patterns of type III and type I were the most common for both sexes. The development of systems for lip print analysis is necessary, mainly concerning digital methods. 相似文献