利用傅立叶变换红外光谱技术快速检验静电复印纸

目的建立一种利用傅立叶变换红外光谱技术快速检验静电复印纸的新方法。方法采用傅立叶红外光谱仪对近似静电复印纸进行了快速检验,同时分析了新方法的技术特点。结果采用本文所述的方法可以对近似静电复印纸进行准确的快速检验。结论利用红外光谱技术检验纸张是一种较新颖的,快速、灵敏、准确的纸张检测技术,能对纸张的品牌种类,甚至批次进行鉴别,对大量样本鉴别和碎小纸片鉴别尤其适用。     

扫描电镜/能谱法检验激光打印文件

目的 应用扫描电镜/能谱法检验不同品牌和型号激光打印机的打印文件,实现对不同机型打印文件的区分。方法 收集不同品牌和型号激光打印机10台,利用扫描电镜/能谱仪对相同的打印字符进行无机元素分析,获得样品的能谱图和mapping分析图,对样品进行定量和半定性分析;同时收集10个不同品牌的A4静电复印纸,分析纸张对实验结果的影响。结果 依据所含元素的种类可以将10台激光打印机分为四类;依据主要元素相对百分含量的比值,对不同品牌和型号激光打印文件进行区分;研究结果表明纸张因素对定性结果影响较小,对定量结果影响较大。结论 扫描电镜/能谱法可以简单、快速、无损的区分和识别激光打印文件,可以应用于二次打印文件的检验,为侦查破案提供线索。     

静电复印纸的FT－Raman光谱检验

对23种品牌的静电复印纸的拉曼图进行了分析,根据填料峰的不同可将其分为三大类根据纤维素峰和木素峰的相对峰强度比的不同,利用正态分布的t检验方法对静电复印纸作了进一步区分,为区分不同牌号的静电复印纸提供了一种参考方法.     

TFD-2纸张手印快速显现系统的应用

目的介绍一种利用特殊的红外热成像技术显现常见纸张上汗潜手印的新方法。方法利用英国Foster4-Freeman公司生产的TFD-2纸张手印快速显现系统,通过特殊的红外热成像技术,使汗潜手印呈现强烈荧光,从而显现手印。结果红外热成像方法处理后,汗潜手印在特种激发光（带宽为450nm-510nm）激发下显出较强的橙色荧光;持续处理后,汗潜手印在自然光下呈棕褐色,并在短波紫外光源（254nm）激发下也可显出清晰连贯的手印纹线;而且,新鲜和陈旧手印均有较好的显现效果。结论TFD-2纸张手印快速显现系统显现纸张上汗潜手印的方法,具有操作简单、快速安全、无需化学试剂、显现效果明显的特点,适合推广使用。     

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。     

傅里叶红外图像无损检验添改数字的研究

目的建立利用傅里叶红外图像系统无损检验添改数字的检验方法。方法采集同种同品牌、同种不同品牌及不同种书写材料书写的数字1改为4和3添加为8两类样本的红外图像，根据红外吸收的光谱信息对其添改进行检验。结果同种不同品牌及不同种书写材料对红外吸收强弱不同，形成的红外图像有差别；同种同品牌书写材料对红外吸收强弱没有明显差别。结论该检验方法不损坏检材，重现性好，并且纸张成分对其分析结果基本上无干扰。     

X射线荧光光谱法检验打印纸张的结果分析

目的对不同品牌的打印纸进行区分和鉴别。方法对21种不同品牌的打印纸进行X射线荧光光谱法（XRF）和X射线衍射法（XRD）检验，利用相关分析和聚类分析法对21种打印纸进行分类。结论XRF、XRD分析和数据分析相结合对纸张具有较好的区分能力。     

波长色散X射线荧光光谱法检验纸张中的常量和微量元素

目的研究X射线荧光光谱元素分析法对常见纸张的鉴别能力。方法应用波长色散X射线荧光光谱仪对29个纸张样品中常量和微量元素进行了定性和定量分析。结果在样品量为mg级时,不但检出填料中常见的Si、Ca、Mg、Cl等主体元素,还能检出Al、S、P、K、Fe、Sr等10多种微量元素。结论用该方法既可对纸张的种类进行鉴别,对不同品牌的打印纸也有较好的区分。     

数码相机在紫外荧光照相中的应用

紫外荧光照相是利用紫外线作为激发光源 ,激发物体在可见光区发射荧光 (有时也在长波紫外区和红外区发射荧光 ) ,再用照相的方法记录物体在紫外光激发下发射的可见荧光。实际工作中 ,有些在普通光线下看不清或看不见的痕迹物证 ,运用紫外荧光照相方法可以把它们拍照下来 ,此外 ,不同质的物质 ,在一定强度和波长的光源的激发下 ,会产生不同强度或不同色彩的荧光 ,根据荧光特征就可以检验物质的真伪或异同。紫外荧光照相是刑事照相中重要的技术手段 ,数码照相机在刑事照相中的大量使用 ,使原本较复杂的紫外荧光照相的操作变得简单了 ,运用数码…     

Micro-ATR无损检验纸张上印油

利用付立叶变换显微红外光谱法中的Micro-ATR技术无损测定了纸张上的10种红色印油,结果表明,纸张上印痕的微区衰减全反射谱图可以明显地识别其色料和溶剂的结构组成,实现有效区分不同牌号印油的目的.     

苯酚-硫酸分光光度法检验复印纸的研究

本文建立了苯酚-硫酸分光光度法测定复印纸水解液中还原糖含量鉴别复印纸的方法。还原糖与浓硫酸在一定条件下反应生成的产物可与苯酚反应生成有色物质,当检测波长为490nm,线性范围为0．02～0．14mg／ml,葡萄糖含量与吸光度的线性关系为Y=6．9425C＋0．0284,相关系数r=0．9997,平均加标回收率为99．29／6,相对标准偏差为0．46％。该方法具有简单、快速和灵敏度高等优点,为纸张的种类鉴别提供了一种实用的方法。     

Postmortem interval of skeletal remains through the detection of intraosseal hemin traces. A comparison of UV-fluorescence, luminol, Hexagon-OBTI®, and Combur® tests

With the goal of obtaining additional practically applicable methods for estimating the PMI of skeletal remains, 39 samples of human and 5 samples of domestic animal long bones with known PMI (PMI=1 to approximately 2000 years) were tested with two established methods (UV-fluorescence of a freshly sawn cross-section and the luminol test) and two screening tests (Hexagon-OBTI? test and Combur? test) that were being tried out in this context for the first time. The hypothesis underlying this experiment was the supposition that the PMI-related chemiluminescence of the luminol reaction for bone is based on the presence of persisting hemin from hemoglobin molecules in bone. Our results showed that lack of luminescence and reduced UV-fluorescence were more meaningful results for estimating PMI and excluding forensic relevance than a positive luminol reaction or strong UV-fluorescence, as both of the latter findings revealed the limitations of these methods in this particular context. Particularly for cases showing a positive luminol reaction, the use of additional absolute dating methods may be indicated. Against our expectations, both the Combur? test strips and the Hexagon-OBTI? test, which were both devised to demonstrate blood, delivered negative results for all samples. They are thus not suitable for estimating the PMI of skeletal remains. Future research will be necessary to elucidate whether the negative results obtained for these tests may be due to the poor solubility of potentially present hemoglobin or hemoglobin breakdown products in the Tris buffer used in this experiment.     

Microscopical study on estimation of time since death in skeletal remains

For the purpose of estimating time since death in skeletal remains, postmortem changes in human compact bones were examined by microradiography and electron microscopy. The UV-fluorescence of the peripheral zone of compact bone was also examined by microscopic spectrophotometry. Microradiographic examination revealed no morphological changes in bones left in the open air for long periods, except one of 15 years since death. In bones left in the soil, vacuoles of 5-10 microns diameter, which contained a honeycomb-like structure formed by small vacuoles of 0.5-1 microns diameter, were found in the peripheral zone of the substantia compacta approximately 5 years since death, and in bones of 6 years or more, this change extended to the mid-zone. In bones left in the sea for 4-5 years, vacuoles of 5-10 microns diameter were observed in the outer peripheral zone of the substantia compacta. The relative intensity of UV-fluorescence in bones dwindled with time since death and the correlation coefficient was considerably high.     

Nondestructive Biological Evidence Collection with Alternative Swabs and Adhesive Lifters

In forensic science, biological material is typically collected from evidence via wet/dry double swabbing with cotton swabs, which is effective but can visibly damage an item's surface. When an item's appearance must be maintained, dry swabbing and tape‐lifting may be employed as collection techniques that are visually nondestructive to substrates' surfaces. This study examined the efficacy of alternative swab matrices and adhesive lifters when collecting blood and fingerprints from glass, painted drywall, 100% cotton, and copy paper. Data were evaluated by determining the percent profile and quality score for each STR profile generated. Hydraflock^® swabs, BVDA Gellifters^®, and Scenesafe FAST? tape performed as well as or better than cotton swabs when collecting fingerprints from painted drywall and 100% cotton. Collection success was also dependent on the type of biological material sampled and the substrate on which it was deposited. These results demonstrated that alternative swabs and adhesive lifters can be effective for nondestructive DNA collection from various substrates.     

X‐ray Powder Diffraction for Characterization of Raw Materials in Banknotes

We report about the X‐ray powder diffraction characterization of crystalline materials used to produce genuine and counterfeit banknotes, performed with a single‐crystal diffractometer that permits fast and nondestructive measurements in different 0.5‐mm sized areas; 20‐euro denomination genuine banknotes were analyzed, and results were compared with counterfeit banknotes. The analysis shows that the papers used to print real banknotes are composed, as expected, of cotton‐based cellulose and titanium dioxide as crystalline additive, but different polymorphs of TiO₂ for different emission countries are evidenced. The counterfeit banknotes are composed of cellulose based on wood pulp; moreover, an unexpected significant quantity of TiO₂ was found to be mixed with calcite, indicating that the paper employed by forgers is not simply a common low‐cost type. The crystalline index and intensity ratios between the peaks attributable to cellulose and fillers can provide additional information to trace back paper suppliers for forensic purposes.     

烧毁复印纸的提取、显现方法研究

目的建立科学的提取、显现烧毁复印纸的方法。方法制备烧毁复印纸,对比喷雾法、气熏法、涂刷法、水漂法、发胶喷雾法对烧毁复印纸的摊平软化效果;对比夹板固定法和胶带粘取法对烧毁复印纸的固定效果;对比光学检验法、化学显现法对烧毁复印纸文件的显现效果。结果喷雾法摊平软化效果整体上优于其他方法;夹板固定法可适用于大多数烧毁复印纸文件,胶带粘取法适用于打印类复印纸文件;光学检验可以显现出黑笔、蓝笔、红笔、2B铅笔字迹以及指印,化学显现可以更清晰地显现出黑笔、2B铅笔字迹。结论当烧毁复印纸烧毁程度不明确时,摊平软化可选用喷雾法;当烧毁复印纸内容需进一步检验时,固定优选用夹板固定法;显现烧毁复印纸应根据不同显现客体采取合适的方法。     

热敏纸与压敏纸上的汗液手印显现

根据热敏纸与压敏纸的特性,研制了一种新的汗液手印显现方法,该方法能有效的保持检材原貌,不破坏检材.     

Thermal development of latent fingermarks on porous surfaces—Further observations and refinements

In a further study of the thermal development of fingermarks on paper and similar surfaces, it is demonstrated that direct contact heating of the substrate using coated or ceramic surfaces at temperatures in excess of 230 °C produces results superior to those obtained using hot air. Fingermarks can also be developed in this way on other cellulose-based substrates such as wood and cotton fabric, though ridge detail is difficult to obtain in the latter case. Fluorescence spectroscopy indicates that the phenomena observed during the thermal development of fingermarks can be reproduced simply by heating untreated white copy paper or filter paper, or these papers treated with solutions of sodium chloride or alanine. There is no evidence to suggest that the observed fluorescence of fingermarks heated on paper is due to a reaction of fingermark constituents on or with the paper. Instead, we maintain that the ridge contrast observed first as fluorescence, and later as brown charring, is simply an acceleration of the thermal degradation of the paper. Thermal degradation of cellulose, a major constituent of paper and wood, is known to give rise to a fluorescent product if sufficient oxygen is available [1], [2], [3], [4], [5]. However, the absence of atmospheric oxygen has only a slight effect on the thermal development of fingermarks, indicating that there is sufficient oxygen already present in paper to allow the formation of the fluorescent and charred products. In a depletion study comparing thermal development of fingermarks on paper with development using ninhydrin, the thermal technique was found to be as sensitive as ninhydrin for six out of seven donors. When thermal development was used in sequence with ninhydrin and DFO, it was found that only fingermarks that had been developed to the fluorescent stage (a few seconds of heating) could subsequently be developed with the other reagents. In the reverse sequence, no useful further development was noted for fingermarks that were treated thermally after having been developed with ninhydrin or DFO. Aged fingermarks, including marks from 1-year-old university examination papers were successfully developed using the thermal technique.