共查询到18条相似文献,搜索用时 93 毫秒
1.
基层技术部门每年都要勘查很多的汽车现场,遇到最棘手的问题是车内的手印处理。笔者介绍一种车内潜在手印显现方法。采取车辆内用502熏显,寻找、提取车内各部位的汗潜手印。车内光洁部位遗留的手印,皮革、塑料、金属材料表面的显现效果比较满意。 相似文献
2.
加热502胶熏显手印的改进方法 总被引:1,自引:0,他引:1
加热502胶水熏显手印,通常需要将客体置于502熏显柜、聚乙烯薄膜罩等密封容器中进行,使用这类显现器材的优势是熏染速度快,数量多,一次可同时熏染多个客体,但现场手印的承载客体千差万别,对一些较为特殊的客体,应用上述密封加热方法,有时存在一些不足:①对体积较大或不可提取的客体,无法在熏显柜、聚乙烯薄膜罩等密封容器中进行加热熏显; 相似文献
3.
现场勘查在遇到需要“502”胶熏显的指纹时,通常将客体放在容器中熏显,无法提取时就用滤纸贴附熏显。滤纸熏显这种方法使指纹显现得比较快,同时也存在难以把握之处。主要存在3个方面的问题:一是“502”胶滴在滤纸上的干湿程度较难掌握。以往要使“502”胶滴在滤纸上后,滤纸贴在客体上并在熏显过程中,不会将“502”胶转移到客体上从而破坏客体上的指纹,有时需要多次试验。如在现场实际操作过程中,稍没掌握好,就很容易使滤纸上的“502”转移到客体上破坏指纹。好,滤纸上的“502”胶就已固化,特别是在熏显较陈旧的指纹时。三是熏显好坏难以掌握… 相似文献
4.
在现场勘验中,作案人进入现场后触碰透明塑料布类制品是经常遇到的。例如:农用薄膜、塑料袋、香烟盒包装薄膜及其它物品包装物等。有些塑料布质地薄、软、易褶皱,在拍摄时很难将其抚平,用常规方法拍摄制作出来的照片纹线由于褶皱痕迹会有些许变形,给鉴定工作带来一定困难。笔者在工作实践中找到一种较简单的处理方法,介绍如下。 相似文献
5.
6.
“502”加膜一染色法显现油质手印 总被引:1,自引:0,他引:1
目的探索方便快捷并有效的油质手印显现方法。方法用“502”熏显常见玻璃、粗糙皮革等不同客体上不同遗留时间的油汗手印和多油手印,加染后用透明胶带粘取。结果显现了30天左右大多数非渗透性客体上的油质加层手印,10天左右渗透性客体上的油质渐层手印。结论本方法适用于油质加层手印及部分油质渐层手印的显现,显出手印清晰,流畅,不破坏手印。 相似文献
7.
上世纪80年代初期,502熏显技术开始广泛应用于犯罪现场的勘验工作。至今,在各类犯罪现场的勘验中确实发挥了不小的作用。目前大多数现场上提取的原物,基本上都习惯用502技术进行处理。如何在各种条件下、各种客体上进一步发挥其应有效能,一直是专业人士引以关注的课题。从理论上分析,502胶中的氰烯酸乙酯分子能与人体汗液成分聚合形成白色可见产物,使物体表面上的潜手印被固定,通常提取的方法是拍照。由于502胶加热后生成的白色物质附着在汗液指掌纹上,出现在深色平面客体上往往拍照效果较好,但在浅色、白色和花(杂)色客体上所形成的反差效… 相似文献
8.
502熏显汗潜手印的方法,在我国推广应用已有十几年的历史了.应用实践证明,应该让其由试验室、小型密封容器的应用,扩展到整个犯罪现场汗潜手印的熏显应用.1 试验经过1987年,我市连续发生8起保险柜被撬盗案件.由于保险柜体积大,质量重,不易搬动我们根据502熏显汗潜手印原理,采用了筒状塑料地膜套装密封熏显法.空间3m~3~5m~3不等,502用量3g/m~3,采用电烙铁、蜡烛加温法,30min熏显完毕,汗潜手印及保 相似文献
9.
目的 探究在常见塑料材质、玻璃等非渗透性客体上,502胶熏显后用Ardrox荧光液染色显现潜在手印方法。方法 收集12种常见塑料材质、玻璃等非渗透性客体,用Ardrox荧光液染色与罗丹明6G、BBD、龙胆紫进行显现潜在手印对比实验。同时测试Ardrox荧光液染色最佳遗留时间,采取控制变量,改变单一变量,选取显现效果最好的锡箔纸作为实验检材,分别在遗留1、3、5、7、15 d后进行显现。结果 在大多数常见塑料材质、玻璃等非渗透客体上,502胶-Ardrox荧光液显现效果优于罗丹明6G、BBD和龙胆紫,在锡箔纸、黑塑料袋、易拉罐上效果最好;在浅色客体或深色客体上,Ardrox荧光液均能取得很好的显现效果,光盘上的显现效果不佳。最佳遗留时间测试结果表明,Ardrox荧光液显现指纹,遗留15 d以内的样本都可以很清晰的显现出来,超过15 d,显现效果明显减弱。结论 502胶-Ardrox荧光液显现法显现率高、荧光强。 相似文献
10.
11.
12.
Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingermarks and in some cases has been shown to enhance prints developed with cyanoacrylate (CA) (superglue) fuming. This work utilizes scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingermarks on low-density polyethylene. CA is shown to act principally on the eccrine deposits around sweat pores, where polymerization results in long polymer fibrils a few 100 nm in width. Subsequent VMD processing results in additional areas of development, for example, between pores. However, the primary mode of deposition of zinc is by interaction with the polymerized CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerization are also enhanced with the VMD process, resulting in increased print development. 相似文献
13.
The use of superglue vapors to detect latent fingerprints, known as superglue fuming, is a chemical process that has not been fully described. The role of the fingerprint material in the process, leading to formation of methyl cyanoacrylate polymer at the site of the fingerprint, remains to be established. Films of liquid alkanes respond similarly to actual fingerprints in the fuming experiment. Their responses depended on the hydrocarbon used, viscosity, and film thickness. Aspects such as film thickness appear to be relevant for actual fingerprints as well. A model was proposed in light of these observations. The model compares the process with gas chromatography, in which molecules partition between the gas phase and a stationary phase. Aspects such as accumulation of superglue monomers by partitioning into a thin film (or wax) are consistent with the preferential response of fingerprints on surfaces relative to the background. 相似文献
14.
Contrasting or enhancing of cyanoacrylate ester-fumed latent fingerprints deposited on solvent-sensitive materials such as oil marker writings and rough surface materials such as unglazed earthenware is not easy by conventional dye solutions dipping or dye powder dusting. In this study, a new vapor-phase staining method using p-dimethylaminobenzaldehyde (DMAB) is proposed for staining such materials. DMAB has high volatility and selective absorbability to cyanoacrylate-fumed fingerprints, so that cyanoacrylate-treated samples can be easily stained by leaving them simply in a closed container along with DMAB crystals for 48-96 h at room temperature or in conjunction with the use of mild heating. The stained fingerprint could be excited by UV irradiation (365 nm), and the fluorescent fingerprint was photographed through a UV cut-off filter (420 nm). The new method achieved minimally destructive fluorescent staining for the solvent-sensitive samples and the rough surfaced samples. 相似文献
15.
Emily Sonnex Ph.D. Matthew J. Almond D.Phil. John W. Bond O.B.E. D.Phil. 《Journal of forensic sciences》2016,61(4):1100-1106
A method has been developed for the visualization of latent fingerprints on fabrics, which is based upon cyanoacrylate (superglue) fuming followed by imaging using an infrared microscope. Results show that imaging on smooth, shiny fabrics such as polyester, silk, nylon, and acetate of different colors and patterns can give an improvement over existing enhancement methods. Results for cotton and polycotton were less successful and it is thought this may be due a combination of the presence of the carbonyl functional group in these fabrics as well as their absorbency to fingerprint sweat. The carbonyl peak (1700 cm?1) provided the optimum spectroscopic feature to map and image a fingerprint. Comparisons between infrared mapping at a specific frequency range and principal component analysis showed that improved imaging was obtained with principal component analysis. 相似文献
16.
17.
Om Prakash Jasuja Gagandeep Singh 《Forensic Science International Supplement Series》2009,192(1-3):e11-e16
Thermal paper finds its extensive use in the modern day life and could act as a vital piece of physical evidence carrying latent fingermarks. A large number of citations are available in literature suggesting various techniques to develop these marks but all are suffering with one or the other drawbacks such as complex and cumbersome procedure, pre- or post-treatment, background coloration and efficiency to develop aged fingermarks. In present study, a very simple and novel method involving iodine fuming has been suggested to develop fingermarks which were not only permanent but also without any background coloration. The suggested method does not involve any pre- or post-treatment of the substrate and was able to develop very old fingermarks (upto >1 year). In this study an attempt has been made to explain the reaction mechanism of the process. In case of different types of thermal papers, presence of different substituents on leuco dye (lactone ring) structure resulted in development of different colored fingermarks upon reaction with iodine. Sebaceous material laden marks have been found to be more intensely developed as compared to eccrine marks, and the difference was more pronounced in case of aged fingermarks. 相似文献
18.
Bond JW 《Journal of forensic sciences》2008,53(6):1344-1352
Redox reactions taking place between the surface of a metal and fingerprint residue have been expressed thermodynamically in terms of both the Nernst equation for reduction potential and the complexation constant for the formation of complex metal halide ions in aqueous solution. These expressions are used to explain experimental results for the corrosion of 10 different metal elements by fingerprint residue in air at room temperature. Corrosion of noble metals, such as silver and gold, supports the proposition that the degree of metal corrosion is enhanced by the presence of chloride ions in eccrine sweat. Extending the experiments to include 10 metal alloys enabled the construction of a fingerprint corrosion series for 20 different metals. Fingerprint corrosion on metals alloyed with > approximately 40% copper was found to display third level fingerprint detail. A comparison of both conventional ink on paper and digital (Livescan) fingerprinting techniques with fingerprints deposited on 9 Karat gold alloy has shown that gold alloy depositions are least susceptible to third level detail obliteration by poor fingerprint capturing techniques. 相似文献