利用FT-IR检验纸张初探

目的初步探讨利用傅立叶红外光谱仪对纸张检验的鉴别力。方法利用傅立叶红外光谱仪对不同种类纸张、同一厂家不同批次的纸张进行检验。结果通过比较红外光谱图中出现的特征峰差异,确定纸张的差异。结论用该方法可以对不同种类纸张、同一厂家不同批次的纸张进行区分,同时可以分析纸张中有机物的特征基团。     

论指纹检验中的假定

在指纹检验中,能否在被检指纹中找到有价值的细节特征,对指纹检验的成败具有重要作用。但是,究竟什么是指纹特征?如何对指纹特征进行分类?发现指纹特征是一个怎样的过程?本文参照其它学科的研究方法,提出一种解决这些问题的办法,并称之为“指纹假定”,现论述如下: 1 提出指纹假定的思维过程 指纹假定的提出,是从为指纹特征下定义开始考虑的。长期以来,痕检人员在指纹检验中一直沿用九种指纹特征,名称分别是起点、终点、分歧、结合、小钩、小     

应用指纹系统对现场指纹的检验

在对指纹自动识别系统实际运用的过程中证实 ,现场指纹的变形或模糊都会影响指纹的比中率。当前 ,人们认为在对现场指纹的检验中特征不能少于 12个。在工作中也有少数技术人员不愿对特征少的现场指纹进行查询 ,因为查中率低。因此 ,笔者对这一问题进行了实验分析并得出了解决这一问题的可靠方法。在实际工作中我们对变形、模糊的现场指纹根据指纹的不同情况采取不同的检验方法 ,同样查中许多案件。如经常遇到变形较大、纹线较少、模糊不清的现场指纹 ,对于这样的现场指纹 ,我们采取了以下做法并取得较好效果 :1　解决变形现场指纹出现的差异…     

指纹擦划痕迹检验初探

在实际办案过程中,指纹的检验应用仅仅涉及到具有一定数量的纹线和特征的指纹.而在现场勘查过程中,经常会提取到一些纹线稀少,特征不明显,按常规方法无法检验鉴定的指纹擦划痕迹.这类指纹擦划痕迹是否完全没有利用价值呢?下面对指纹擦划痕迹检验略作探讨,供同行参考.     

彩色复印指印与捺印指印的区别检验

当前,检验借据、契约等票据上指印的案件较多,笔者在受理一起经济纠纷民事案时,发现票据上的指印为彩色(红色)复印指印,是当事人曾在其他票据上捺印过的指纹,被转印于这张借据上.因此,在检验鉴定时应特别注意区别彩色复印指印.通过制作若干枚实验样本进行实验,现将区别复印指印与捺印指印的检验方法介绍如下:1 纸张上有无翘起的纸纤维 将复印指印与捺印指印分别置于立体显微镜下观察,复印指印处的纸张没有纸纤维翘起;而捺印指印多为印油印泥等形成,有一定的液体性质,因此,捺印指印处有较多纸纤维翘起.     

作用力对指纹形态和细节特征的影响

指纹鉴定主要根据指纹的纹型、流向、细节特征等进行检验判断，本文通过一枚整体变形指纹（见图1）的检验进行分析。     

纹线中空特征在指纹比对中的应用

目的探讨纹线中空特征应用于某些残缺、特征数量不足的指纹检验中的可行性。方法引入指纹三级特征理论,从该特征的存在机理、稳定性特点及与其它类似特征的区别等进行观察。结果纹线中空特征稳定存在,且在比对工作中具有可操作性。结论纹线中空特征是对常规特征的补充,对指纹比对工作具有实际意义。     

应用红外化学成像技术显现潜在的指印

目的应用红外化学（光谱）成像技术显现潜在指纹。方法采用这种新技术进行显现潜在指印的初步实验。结果显示了其对复杂图案背景上指印突出的显现能力。该成像技术具有物质形态特征检验和物质成分检验双重分析能力，在法庭科学领域具有重要的应用价值。     

残缺指纹少量特征的同一认定

我们把只出现3、4个特征的残缺指纹称为少量特征指纹。在指纹检验中,常常会遇到对只有少量特征的残缺指纹的检验。有关权威专业刊物曾报导:指纹的同一认定必须有6个以上相同的特征。由于现场条件的限制、显现固定手印方法落后、手印局部持征较少等原因,所提取的现场指纹特征出现得极少,达不到同一认定的足够数量。笔者认为,在如下特殊条件的配合下,仅凭3、4个特征相同就可以作出同一认定结论。     

指纹自动识别系统的应用

在应用了cafis指纹自动识别交流2年多来,通过实践,我们发现本系统在比对结果中出现的指纹都是捺印清楚,特征明显的指纹,所以,在指纹的搜集上,我们首先是改变原来管教和户籍警捺印指纹的搜集方法,由技术人员定期到两所和深入基层进行搜集和捺印,从而在指纹的人员质量上有了保证。其次,是改善捺印条件,采用指纹捺印盒进行捺印,改变原先的用油墨捺印方法,从根本上提高捺印质量,进一步为准确抽取特征点打下了基础。     

Study of the adhesion of explosive residues to the finger and transfer to clothing and luggage

It is important to understand the extent of transfer of explosive particles to different surfaces in order to better evaluate potential cross-contamination by explosives in crowded security controls such as those at airports. This work investigated the transfer of nine explosive residues (ANFO, dynamite, black powder, TNT, HMTD, PETN, NH₄NO₃, KNO₃, NaClO₃) through fingerprints from one surface to another. First, the extent of adhesion of explosive residues from different surfaces to the bare finger, nitrile and latex gloves was studied. Then, the transfer of explosive residues from one surface to another through fingerprints was investigated. Cotton fabric (hereinafter referred to as cotton) as clothing material and polycarbonate plastic (hereinafter referred to as polycarbonate) as luggage material were chosen for the experiments. These surfaces containing explosive particles were imaged using a reflex camera before and after the particles were transferred. Afterwards the images were processed in MATLAB where pixels corresponding to explosive residues were quantified. Results demonstrated that transfer of explosive residues frequently occurred with certain differences among materials. Generally, the amount of explosive particles adhered to the finger decreased in the following order: skin>latex>nitrile, while the transfer of particles from the finger to another surface was the opposite. The adhesion of explosive residues from polycarbonate to the finger was found to be better compared to cotton, while the amount of particles transferred to cotton was higher.     

Enhancing contrast of fingerprints on plastic tape

Many of the currently available fingerprinting methods have limited ability to visualize fingerprints on plastic tape without expensive equipment or significant handling of the sample. This is especially true for visualizing fingerprints on black electrical tape. This study sought a hands-off method to produce easy visualization of fingerprints on different types of plastic tape, including black electrical tape, without the need for expensive equipment. The methods selected were to sublime disperse dyes into the tape, both with and without the fuming of cyanoacrylate, everywhere except for where the fingerprint was applied. The resulting color contrasts provided enough differentiation to visualize fingerprints on plastic tape under ambient light. Sequential fuming with cyanoacrylate followed by disperse dyes provided the best visualizations on all tapes, and cyanoacrylate followed by disperse yellow 211 clearly visualized fingerprints on black electrical tape.     

上转换发光微粒悬浮液显现手印技术初探

目的 建立NaYF4∶Er,Yb微粒悬浮液显现手印技术方法并界定适用范围与条件.方法 用NaYF4∶Er,Yb微粒悬浮液显现瓷砖、玻璃等19种（各50枚）不同客体上皮脂汗手印,并对结果进行分析比较.结果 该方法对背景复杂的非渗透性客体上的油汗手印显现良好,其效果优于普通ZnO小颗粒悬浮液.结论 该方法操作简便、适用客体广泛、背景干扰少,适合进一步研究推广.     

酸性黄显现非渗透性客体上血潜手印初步探究

目的建立一种酸性黄显现非渗透性客体上血潜手印的方法。方法制备白色瓷砖、黑色塑料袋、黑色瓷瓶、易拉罐侧面、深色铁质茶叶盒等为客体的捺印手印,配置以酸性黄作为主要成分的染色剂,对其进行固定、染色、漂洗,在多波段光源下观察。结果在440nm激发光源条件下,通过橙色护目镜观察有很强的黄色荧光特征。结论酸性黄显现法具有操作简单、显现效果明显、能排除深色背景干扰的特点,容易推广使用。     

SWP荧光剂熏显油脂手印方法的初步研究

目的建立SWP荧光剂熏显油脂手印的新方法。方法选取12中常见客体,根据试验需要分别捺印油脂手印144枚和油汗混合手印100枚,用多功能手印显现柜加热升华SWP荧光剂,熏显渗透性和非渗透性客体上的手印。结果油脂手印显现出了142枚,显出率达到98．6％;油汗混合手印,非渗透性客体共显出100枚,显出率达到100％,渗透性客体共显出95枚,显出率达到95％。结论SWP荧光剂对油脂手印的显现效果良好,可与“502”同时熏显,且不影响茚二酮等其他方法的进一步检验。     

Toward multidimensional information: A derivatization-free UHPLC-QqQ MS/MS method for amino acid components of fingerprint

The analysis of fingerprint chemical composition is a meaningful way to excavate the multidimensional information of fingerprint, including the donor profiling information and the age of a fingerprint, which broadens the evidential values of fingerprint, especially for the partial and distorted fingerprint. But the research remains still in the pilot phases or is ongoing. Amino acids are the dominant organic substances in latent sweat fingerprint and influenced by many donor factors. Hence, their content reflects personal information of donors. Forensic science will be revolutionized if suspects can be individualized by their amino acid content. The diverse nature, distinct physicochemical properties, and ultra-micro levels of amino acids present in fingerprints make it hard to detect. A high sensitivity method for detecting and quantifying multiple amino acid components is required. UHPLC-QqQ MS/MS offers high sensitivity, high separation, simultaneous multicomponents detection, and no derivatization, making it an ideal method for detecting and analyzing amino acids in fingerprints. Therefore, in this study, we propose and validate an efficient UHPLC-QqQ MS/MS method for the extraction and analysis of 13 amino acids from fingerprint. We compared the results of amino acids of 10 different substrates and found that the inherent amino acids in most porous substrates would have been extracted along with the fingerprint amino acids, making them unsuitable for quantitative amino acid analysis. Instead, plastic sheets are ideal substrates for laboratory studies. Then, extensive experiments were conducted among 30 donors for multidimensional information analysis. The type of samples analyzed were eccrine-rich fingerprints. A Binary Logistic Regression (BLR) model was developed, and the female and male donors were successfully differentiated by amino acids in fingerprints. Two other mathematical models were also developed to verify the accuracy, and all three different mathematical models were able to identify donors of different genders with over 90% accuracy. This demonstrates that amino acids have the potential to provide more information for donors as metabolic markers. In the future, we will conduct a series of experiments to analyze more multidimensional information for individual identification by amino acid content in the fingerprint.     

利用CdSe巯基乙酸溶液显现水浸客体表面潜手印

目的研究水浸客体表面潜指纹的显现方法;方法利用CdSe巯基乙酸溶液显现被水浸泡过的黄色封箱胶带、黑色塑料袋、玻璃等常见非渗透性客体上的潜手印,讨论影响水浸非渗透性客体上潜手印显现效果的各种因素,并与传统方法进行比较,初步探讨了CdSe巯基乙酸溶液显现水浸非渗透性客体表面潜手印的方法;结果使用巯基乙酸包覆CdSe纳米复合材料显现潜在手印,使每分子纳米复合材料外表包覆足够数量的羧基,则可以提高它同手印残留物的结合能力,从而得到更高清晰度、更高分辨率的手印显像;结论巯基乙酸包覆CdSe纳米复合材料可以很好的显现水浸塑料、胶带等表面潜指纹。     

Physical Characterization and Recovery of Corroded Fingerprint Impressions from Postblast Copper Pipe Bomb Fragments

Pipe bombs made from 1 mm thick copper pipe were detonated with a low explosive power powder. Analysis of the physical characteristics of fragments revealed that the copper had undergone work hardening with an increased Vickers Hardness of 107HV1 compared with 80HV1 for unexploded copper pipe. Mean plastic strain prior to fracture was calculated at 0.28 showing evidence of both plastic deformation and wall thinning. An examination of the external surface showed microfractures running parallel with the length of the pipe at approximately 100 μm intervals and 1–2 μm in width. Many larger fragments had folded “inside out” making the original outside surface inaccessible and difficult to fold back through work hardening. A visual examination for fingerprint corrosion revealed ridge details on several fragments that were enhanced by selective digital mapping of colors reflected from the surface of the copper. One of these fingerprints was identified partially to the original donor.     

新型荧光502粉末显现手印技术的改进研究

目的 对新型粉末状荧光502显现手印的方法进行进一步探索和完善,确保其高效便捷和科学准确.方法 将PolyCyano UV粉末加热至230℃使其升华,待该粉末在手印纹线上聚合附着后用长波紫外线或蓝光激发拍照,并与初步研究结果相比较.结果 大部分非渗透性光滑客体表面上的汗潜手印均有很好的显现效果.结论 该方法使显现流程更加高效便捷、显现时间短、无需二次染色增强、不破坏生物检材,适合推广使用.     

Fingerprints as evidence for a genetic profile: morphological study on fingerprints and analysis of exogenous and individual factors affecting DNA typing

Material recovered from 374 fingerprints left by eleven laboratory workers on three different substrates (glass, wood, metal) at a standard pressure time of 30 s, with and without preliminary handwashing, was submitted to morphological, quantitative, and type analysis. Morphological and agarose-gel electrophoresis analysis showed that a non-negligible amount of epidermal corneal cells presented apoptotic alterations. The quantity of DNA recovered from fingerprints ranged between 0.04 to 0.2 ng, and in a significant number of experiments no DNA was detected. Handwashing reduced the amount of DNA recovered from fingerprints. The "shedder status" of the donor was a very important factor, causing inter-individual variations in the amount of DNA left by fingerprints. Spurious alleles from laboratory-based and secondary transfer contamination, stutters, and other artifacts described when analyzing low-copy-number DNA and capable of affecting correct profiles were observed.