检材指纹与样本指纹变化的分析研究

目的 依据数理统计所得出的数据分析检材指纹与样本指纹的变化规律;方法 通过在检材指纹与其相对应的样本指纹上建立直角坐标系,得到各细节特征的坐标参数;再利用数理统计分析两者相对应的各细节特征变化的形成原因及规律;结果 得出捺印时手指作用力方向的变化导致检材指纹与样本指纹细节特征之间产生距离差,手指的扭转变化使两者细节特征产生角度差;结论 两者之间的变化是由于捺印时手指作用力方向不同、大小不同所导致.     

浅析现场手印定位对鉴定结论的影响

现场留痕手印通常因作用力及承痕体等外因的影响,出现变形现象,直接影响了检验鉴定结论的准确性。检验鉴定前对现场留痕手印进行全面分析,判定其留痕部位,从而作出准确的鉴定结论。     

Thermal degradation analysis of amino acids in fingerprint residue by pyrolysis GC-MS to develop new latent fingerprint developing reagents

Conventional development of latent fingerprints is compromised when the prints are decomposed by extreme temperatures, such as those encountered when a weapon cartridge is fired, an improvised explosive device is detonated, and/or in arson cases. Understanding how these extreme temperatures alter the chemical and physical properties of latent fingerprint residue could aid in the discovery of a reagent that could effectively develop these decomposed fingerprints. To mimic scenarios where fingerprints may be exposed to high heat conditions, standards of the five most abundant amino acids in fingerprint residue as well as extracted fingerprint residue were pyrolized under controlled conditions. Compounds identified as pyrolytic decomposition products were 3,6-dimethylpiperazine-2,5-dione (from alanine), maleimide, and 2,5-furandione (from aspartic acid). The pyrograms and selected ion traces show these products to hold promise as indicators of decomposed fingerprint residues and, therefore, may serve as good candidate substrates for a developing reagent.     

油红O显现手印配方中各物质的作用验证

目的研究油红O显现手印配方中各物质的作用及其对显现效果的影响。方法对配方中的主要成分进行定性、定量实验来分析、考察实验结果。结果油红O粉末的颜色与显出的手印纹线颜色关系较大,溶液中的氢氧化钠关系着显出的手印纹线与背景的反差。结论 Alexandre Beaudoin公布的配方稳定、显现效果好,值得在实践工作中推广。     

一种改进的碘熏法-碘锌手印显现法

目的为解决传统碘熏法显出手印容易褪色、固定困难等问题。方法提出了一种改进的碘熏法-碘锌手印显现法，实验了不同反应物配比、不同客体材质对显现效果的影响；与常规碘熏法进行了对比实验；并考察了碘锌法显出手印的稳定性。结果碘锌手印显现法可以用于常见渗透性及非渗透性客体上新鲜汗潜手印的显现。该方法不必外加热源，携带、存储和应用更加便利；该方法显出的指纹纹线保存时间与传统碘熏法相比明显延长。结论碘锌手印显现法是一种高效、实用的手印显现方法。     

紫外光谱成像技术显现潜在油汗混合指印的初步探索

目的研究运用紫外光谱成像技术显现潜在油汗混合指印的可行性和方法。方法使用紫外光谱成像仪获取典型潜在油汗混合指印的光谱影像数据资料,比较不同数据处理软件的分析结果。结果紫外光谱成像技术具有显现潜在油汗指印的能力。结论紫外光谱成像技术能够成功显现非渗透性客体表面潜在油汗混合指印。     

短波紫外反射照相显现胶带粘面潜在指印

目的研究胶带粘面上指印的提取方法。方法用短波紫外照相的方法对各种胶带粘面的指印进行拍照提取。结果从理论上解释了短波紫外照相拍照提取胶带粘面上指印的原理,从实践上为短波紫外照相法提取胶带粘面上指印提供技术方法和技巧。结论为胶带粘面指印的提取提供了一种新的方法。     

论纸张上潜在指印显现效果的影响因素及对策

潜在指印是目视不可见的指印反映形象,纸张上潜在指印的显现效果受造型主体及作用力大小、纸张状态及媒介物差异、遗留时间及环境条件等众多因素的影响。在实际工作中,为获取理想稳定的纸张潜在指印显现效果,必须在充分了解检材特性的前提条件下,选择与之适配的显现方法,其基本原则是先作无损显现,再选择破坏性相对较轻的有损法,最后才是可能改变检材原有理化特性的其他方法。     

Comparative study of electrochromic enhancement of latent fingerprints with existing development techniques

To address the challenge of capturing latent fingerprint evidence from metal surfaces, a new method of latent fingerprint enhancement based on electrochromic polymer films has recently been developed. Here, we present a study comparing the development and visualization of nonvisible fingerprints on stainless steel substrates using this electrochromic enhancement approach with three classical methods (dusting, wet powder, and cyanoacrylate fuming). Two variants of the electrochromic enhancement method were utilized with polyaniline and poly(3,4-ethylenedioxythiophene) as the electrochromic materials. Fingerprint samples were taken from different donors (varying in age and gender) and were exposed to different environments for systematically varied periods of time (up to 28 days). The environments represent plausible evidential scenarios: left under ambient conditions, washed with aqueous soap solution, washed with acetone, submerged in water, and maintained at elevated temperature. The electrochromic enhancement procedure frequently outperformed the traditional methods, particularly for samples exposed to more challenging histories.     

Study of poroscopy among South Indian population

Poroscopy is the term applied to a specialized study of pore structure found on papillary ridges of skin as a means of identification. It comes under level 3 detail of identification and hence is more reliable and accurate. The goal of this study is to estimate the importance of poroscopy for identification of individuals and to determine the gender based on frequency, type, and shape of pores. Left plain thumb prints of 200 individuals (100 men and 100 women) aged between 18 and 60 belonging to South Indian population were observed. The results have shown that women tend to have a significantly higher frequency of pores than men. Number of pores ≤ 8 pores/25 mm(2) is more likely to be of male origin and ≥9 pores/25 mm(2) is more likely to be of female origin. There was no significant sex difference based on type and shape of pores.