电子束蒸镀金属膜在手印显现中的应用

In this project, a novel electron beam evaporation (EBE) method will be employed for developing metal-deposited latent fingerprints. We will pursue a broad investigation of such controllable method with non-toxic, nondestructive and low background interference for the visualization of metal-deposited latent fingerprints. EBE method has many advantages such as a broad range of metal materials, low background interference, and the deposition of the continuous and uniform films with in situ accurate thickness control, which can give rise to a performance with good contrast, clear and coherent print lines for the image acquisition of a latent fingerprint. Fingerprints left over time has no influence on the development of a latent fingerprint. Moreover, due to a relatively broad range of substrates for EBE method, more substrates can be performed in the latent fingerprint development field including strong reflective objects and strong background fluorescence. In addition, due to the nondestructive deposition of EBE method, the metal-deposited latent fingerprints can be performed in the subsequent investigation of other detections such as illicit drugs, drugs and explosives. The mechanism of the development of metal-deposited latent fingerprints will be demonstrated. The novel method with high quality development, simple operation, a broad range of applicaions, low toxicity and nondestructive deposition for developing latent fingerprints will be developed. In this project, such excellent method will be introduced into the latent fingerprint development field, which will improve efficiently the extraction yield of difficult fingerprints. This project will provide experimentally and theoretically strong clues and basis in criminal detections.

本项目首次将电子束蒸镀金属膜应用于手印显现领域，旨在寻找新的无毒、无损、低背景干扰、可控的手印显现新方法并对其显现机理和后续成像、结构、特征分析。将电子束镀膜技术应用于显现潜手印主要是利用电子束蒸发镀膜具有电子束能量高可蒸镀材料范围广，膜厚可控，成膜面积大均匀、连续。显出手印纹线清晰连贯，反差明显，细节特征表现良好等特性，显现后的手印具有鉴定价值。采用该方法手印的遗留时间不影响其显现效果，且可显现强反光、强背景荧光等强背景干扰的特殊承痕体上的手印。另外，该方法可无损显现手印，有利于研究手印分泌物中是否含带有违禁药品、毒品或爆炸品等。通过本项目将揭示电子束蒸镀膜法显现潜手印的相互作用机理，开发显现效果优良、操作方法简便、适用范围广泛的手印显现技术。将电子束蒸发镀金属膜技术引入手印显现领域，可极大提高疑难手印的提取率，为重大疑难案件的侦破提供重要线索和依据。

随着现在犯罪分子反侦察能力的提高，在犯罪现场留下的基本为潜手印。潜手印即为用肉眼观察不到或观察不清晰的手印，需采用特殊手段进行显现。目前采用的手印显现手法存在其各种弊端，最直接的是其易破坏潜手印中含带的DNA信息，而DNA是另一重要的个体识别信息。在实际案件侦办中潜手印和DNA往往需相互印证，因此如何实现潜手印显现和DNA的共同无损提取是近年来刑事技术和犯罪现场重建领域最关注的课题之一。.本项目采用电子束蒸镀金属膜作为潜手印的显现技术，以痕检比对显微镜作为提取技术，清晰地显现了潜手印的细节特征，实现了潜手印信息的提取，并后续实现了潜手印中DNA的无损检验。同时，揭示了电子束蒸发镀金属膜手印显现机理。首先，采用电子束蒸镀技术在具有潜手印的塑料、硅片、玻璃等承痕体进行超薄金属镀膜(5-30nm)，通过痕检比对显微镜可以清晰地观察到潜指纹的细节特征，如指纹类型，纹线结构等特征，并且对于陈旧的潜手印，也能够通过电子束蒸镀技术实现潜手印显现。其次，系统研究不同种类的金属超薄膜对潜手印显现的影响。结果表明，对于常规的超薄金属都能够实现对潜手印的显现。换句话，电子束蒸镀超薄金属膜潜手印显现法降低了金属材料种类的选择性，这有利于其应用拓宽。电子束蒸镀金属膜手印显现提取后，进一步采用硅珠法后续提取手印中可能存在的DNA信息，使用Identifer Plus扩增试剂盒进行扩增及检测，可以实现手印分泌物中DNA的无损提取。.研究表明，电子束蒸镀金属膜手印显现法是一种无损、低背景干扰、可控的手印显现新方法，该技术可以实现手印显现和DNA的无损共同提取，电子束蒸镀金属膜手印显现法有望大大提高疑难手印的提取率，为实际案件的侦破提供重要线索和依据，在刑事科学领域将有广阔的应用前景。