共查询到17条相似文献,搜索用时 718 毫秒
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傅立叶变换拉曼光谱法鉴别黑色墨水的研究 总被引:4,自引:0,他引:4
采用傅立叶交换拉曼光谱法对6种黑色墨水字迹进行检验分析实验结果表明,能对黑色墨水样品进行有效的鉴别。该方法具有快速、简便、不破坏样品的特点。 相似文献
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在同一介质上二次打印形成文件(对原有文件进行添改)是犯罪分子常用的作案方法。对鉴定机构而言,不同种类的打印机其打印原理、墨水等不同,可根据光学、化学特性的不同进行检验鉴定,即使是同种类的打印机,也能根据打印机自身的字库特征,以及长期使用磨损而反映在打印介质上的自身特征进行检验鉴定。但是对于同一台打印机二次打印形成的文件检验,一直是难题,本文成功检验1例,介绍如下。 相似文献
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利用喷墨打印机二次添加打印,特别是同机添加打印变造文件,是文件检验工作中的难题。喷墨打印机采用串行接字方式,内部结构复杂,喷嘴数目多,同一型号打印机又有多种质量模式。因此,在打印图文上往往留有较多的打印特征,如对接重叠线、对接错位线、横向白线、卫星墨点、墨点错位等。分析爱普生、惠普、佳能三个品牌的20台喷墨打印机不同质量模式的打印文件,发现这些特征重复再现频率较高,不同台打印机打印文件特征差异较大,同一台打印机在不同质量模式下特征出现的位置也不尽相同。通过提取打印文件上的打印特征,分析字车运行方向和打印图文pass数值,分解打印过程并制作检验图谱,判断打印文件的可疑区域是否符合打印规律,为确定二次添加打印提供帮助,提升检验过程的规范性、检验意见的准确性和结果依据的可读性。 相似文献
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有机磷农药薄层色谱溴酚蓝显色法的改进 总被引:1,自引:0,他引:1
目的对有机磷农药薄层色谱溴酚蓝显色法进行改进,使该检验方法更完善。方法采用薄层色谱溴酚蓝—柠檬酸显色。结果显色背景呈纯正的浅黄色,并且颜色稳定。结论该方法操作简单、快速、检测灵敏度高。 相似文献
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当今的社会,科学飞速发展,各种新方法、新技术不断涌现,犯罪分子所采取的新的犯罪手段更是令人防不胜防。日前,我们成功地检验了多起利用打印机伪造印文进行巨额金融诈骗的案件,现就此类伪造印文的特点进行讨论。伪造印文所采用的复印机有全色复印机、双色复印机、单色复印机。伪造印文所采用的打印机是各种类型的激光打印机和喷墨打印机。复印或打印伪造的印文都是将原印文用墨水或墨粉转印到伪造文件上,与真印文相比它们都具有下述特征:(1)图文印迹平实、无抑压盖印痕迹复印或打印的印文是用墨水或墨粉喷涂在纸张表面形成的,纸… 相似文献
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目的 建立荧光法判断激光打印文件朱墨时序的检验方法,并分析不同型号的激光打印机制成的文件与不同材质的印章印文的采墨时序的特征.方法 利用VSCS000文检仪和Photoshop软件,采用荧光法对激光打印文件与印章印文交叉部位的特征进行检验,并对不同型号的打印机制成文字与不同材质的印章印文交叉部位的荧光特征进行分析比对.结果 发现常出现的共性特征为:制成文字先墨后朱,交叉部位的黑色墨迹颜色变淡并可见紫色荧光;先末后墨,交叉部位常常出现黑色墨迹缺损的现象,在缺损处可见紫色荧光点.但也表现出其特有的特征.结论 不同型号的打印机制成的文件与不同材质的印章朱墨时序所表现出来的特征不尽相同,在具体案件鉴定中应进行综合判断. 相似文献
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Chelsea E. Johnson M.S. Paul Martin Ph.D. Katherine A. Roberts Ph.D. Tatiana Trejos Ph.D. Ruthmara Corzo B.S. Jose R. Almirall Ph.D. Alan M. Safer Ph.D. 《Journal of forensic sciences》2018,63(1):66-79
This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same‐colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks. 相似文献
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目的应用热脱附-气相色谱/质谱(TDS-GC/MS)分析,研究7支黑色中性笔墨迹中挥发性溶剂的历时性变化规律。方法选取7支不同品牌的黑色中性笔,分别在A4纸和笔记本上进行一次制样,然后在不同时间点取样,应用所建TDS-GC/MS方法分析墨迹中乙二醇、二甘醇和三甘醇在200余天内的含量变化。结果6支笔中的乙二醇、三甘醇的含量在2个月之内有明显的下降,另1支笔中二甘醇的含量在5个月内还能观察到较明显的下降。目标物的历时性变化趋势能拟合成幂函数或对数函数。不同的纸张、不同的墨水对检测结果均有影响。结论黑色中性笔墨迹中的挥发性溶剂的含量随时间增加而下降,应用所建TDS-GC/MS方法,能为判断需检墨迹是否处于溶剂含量明显变化的阶段提供依据。 相似文献
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Examining the sequence of intersecting seal and laser printing line is a significant method of determining the authenticity and validity of documents. In this study, five brands of stamp pad inks, three types of inkpads and seven kinds of laser printers were used to make heterogeneous line intersections. Observation method of physical characteristics, scraping technique and fluorescence method was used to determine the sequence of intersecting lines. Distinguishing features were noted between the materials produced in both sequences. As the results obtained from the study were positive, these features might provide a scientific basis for accurately determining the sequence between laser printing line and inkpad (stamp pad ink) seal. 相似文献
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Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp‐pad Ink Seal
Guoliang Ouyang M.Sc. Biao Li M.Sc. Pengnan Zhao M.Sc. Xingfei Guo M.Sc. Changliang Wang M.Sc. 《Journal of forensic sciences》2019,64(4):1203-1212
Stamp‐pad ink seals are often placed on important documents, and determining the dating of stamp‐pad ink seal is important to assess the authenticity of a document. In this study, 20 different brands and types of stamp‐pad inks were classified by ultraviolet visible spectrophotometer. Six different brands and types of papers were classified by micro‐Fourier transform infrared spectrometer and visual spectral comparator 6000. Three different brands of stamp‐pad inks and two different types of paper were used to make diachronic samples of the seals. A method was employed to date the stamp‐pad seals by comparing absorbance ratios and inks of known age. Curves were created to show the relationship between the absorbance ratio of ink and the age of the seals. The experimental results showed that the absorbance ratio method was applicable for the relative dating of stamp‐pad ink seals in some cases where the seal was placed on the document within 10 weeks. 相似文献
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目的双溶剂提取法是鉴定圆珠笔油墨字迹相对书写时间的方法之一,该方法简单有效,但在实际办案中发现,提取率的范围对数据的偏差范围有着直接影响。本文旨在通过实验分析偏差范围。方法通过对多种牌号的圆珠笔油墨新书写的字迹样本和自然老化样本进行平行实验。结果得到了不同提取率范围内的圆珠笔油墨提取率偏差范围。结论为双溶剂提取法鉴定圆珠笔油墨相对书写时间的界定提供了较为可靠的实验依据。 相似文献