指纹鉴定标准研究

通过对国内学术界关于指纹鉴定标准构建的几种思路的分析,经综合比较,选择符合点＂数量＂思路作进一步探讨。在简要分析国外指纹鉴定＂数量＂标准研究概况基础上,尝试提出新的＂指纹特征组合概率计算模型＂,并以概率计算方式论证了8个符合点作为鉴定标准的合理性,由此得出一些对指纹鉴定工作可能有现实意义的结论。     

短波紫外反射照相显现曲面客体上的潜在指印

目的：针对公安实践工作中经常遇到的问题，利用短波紫外反射照相提取曲面客体上的潜在指印，为曲面客体上的指印提取提供技术参考。方法：利用环形短波紫外灯小角度照射曲面客体，通过固定曲面客体使之仅沿中心轴线方向旋转，依次拍照记录，再导入Photoshop cc中通过图像拼接技术获得完整的指纹图片。结果：总结相机参数设置、曲面客体所产生的反射光斑以及曲面畸变对成像结果的影响，得出一套优化的拍摄方案。结论：曲率对拍摄难度、拼接难度、成像结果有着直接的影响，曲率越大，需要拍摄的照片数量越多，光斑遗留痕迹越严重，成像结果越差。     

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。     

论残缺指印的特点及鉴定方法

指印是手指末节皮肤乳突花纹遗留的印痕,能反映出手指末节形态的结构特征和乳突花纹的结构特征。在司法实践中,残缺指印的出现率很高,而且由于指印面积小,其纹型难辨,纹线数量少、细节特征少,检验残缺指印比较困难,用常规的鉴定方法难以完成。根据残缺指印的形成特点及鉴定条件从细微处入手、分析形成的原因,通过比对可以得出准确的检验结论。     

不同纸张上浓重红色印泥手印减薄的技术研究

目的建立有效的显现纸张上浓重的印泥手印方法。方法对普通材料纸和打印纸上的浓重红色印泥手印，通过指纹胶带提取转印、氧化漂白减薄、有机溶剂溶解减薄3种技术方法的减薄效果以及它们在减薄过程中的优缺点进行比较，得出适合于各种减薄技术的最佳试剂。结果本研究发现3种方法均可以有效地使浓重红色印泥手印清晰化，进而达到有效显现纸张上浓重的印泥手印的目的。     

利用碘胶纸贴附法显现汗潜手印

碘熏显手印法,是现场勘查中显现汗潜手印的方法之一。由于传统的和现有的方法有时受到现场空间的制约,无法兼顾水平面、垂直面、凸凹面以及狭窄处的手印显现。为此,笔者研制了一种安全、快捷、简易、经济、适用于基层使用的操作装置和方法。     

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.     

基于指纹图像清晰度提取和评估指纹中心点的方法

基于指纹图像清晰度提取和评估指纹中心点的方法是对传统的指纹中心点提取方法的改进,能够加快提取速度、改善提取效果,从而使指纹中心点评估参数更加客观、准确,并达到量化评估的目的。     

DNA recovery after sequential processing of latent fingerprints on copy paper

Forensic examiners must determine whether both latent fingerprint development and DNA profiling can be performed on the same area of an evidence item and, if only one is possible, which examination offers the best chance for identification. Latent fingerprints can be enhanced by targeting different components of fingerprint residues with sequential chemical treatments. This study investigated the effects of single-reagent and sequential latent fingerprint development processes on downstream DNA analysis to determine the point at which latent fingerprint development should be stopped to allow for DNA recovery. Latent fingerprints deposited on copy paper by one donor were developed using three sequential processes: 1,8-diazafluoren-9-one (DFO) → ninhydrin → physical developer (PD); 1,2-indanedione-zinc (IND-Zn) → ninhydrin → PD; and IND-Zn → ninhydrin → Oil Red O (ORO) → PD. Samples were examined after the addition of each chemical treatment. DNA was collected with cotton swabs, extracted, quantified, and amplified. DNA yields, peak heights, number of alleles obtained, and percentage of DNA profiles eligible for CODIS upload were examined. DNA profiles were obtained with varying degrees of success, depending on the number and type of treatments used for latent fingerprint development. The treatments that were found to be the least harmful to downstream DNA analysis were IND-Zn and IND-Zn/laser, and the most detrimental treatments were DFO, DFO/laser, and PD. In general, as the number of treatments increase, the opportunities for DNA loss or damage also increase, and it is preferable to use fewer treatments when developing latent fingerprints prior to downstream DNA processing.     

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.