共查询到19条相似文献,搜索用时 62 毫秒
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文件上印章印文可变性印迹特征通常表现为印文上的异物印迹,文字线条的断线、露白,印文边框的缺损,浓重的印泥(油)点或团块,以及原子印章的套框、支撑爪的印迹等。根据印章的印面结构和印面附着物的变化规律,通过被检验印文与该印章印文的历时样本的比较检验,以印文的可变性印迹特征的异同,推断被检验印文的盖印时间。1利用印面结构不可逆变化特征鉴别印文盖印时间印面结构的不可逆变化的特征,主要表现为印面结构的缺损、磨损特征。这类特征从无到有,由少到多,发展到不同的变化程度,标志印章印面的不同变化阶段。它的异同一般可以界定盖印的… 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
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先将真实印文用扫描仪扫描后输入计算机,经过图像处理后用彩色打印机打印,从而伪造印章印文是近年来出现的一种新的、仿真程度较高的伪造印章印文方式.司法鉴定实践表明,这类伪造印文趋于专业化、技术化,且伪造的印文与真实印文相似度较高,依据传统的鉴定依据和方法难以鉴别真伪,甚至可能误导鉴定人员的判断.因此,本文指出,用色谱法对盖印印文和打印伪造印文的成分检测分析,从二者的溶剂和色料成分差异来判断其真实的形成方式,为科学的检验鉴定工作提供借鉴和依据. 相似文献
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1.测定原理1.1物理原理[1、2]印章盖印时间越长,其印泥固化程度越高,也就越不容易扩散。1.2实验原理以检验纸张为展开板,以氯仿∶乙醇(5∶1)为展开剂,通过测定印泥在纸张上的扩散程度来判定盖章时间。由于盖章的纸张不同,同时考察了溶剂在纸张上的扩散情况,建立一个校正因子。基于扩散程度与时间的关系,我们建立了一个数学模型,得到一个时间扩散程度曲线,以这个曲线来考察未知样的印章时间。2实验部分2.1试剂与仪器氯仿∶乙醇(5∶1),均为分析纯。金相显微镜。镊子,打孔器,微量取液器。2.2实验步骤用打孔器在文件印章处打孔取样(Φ40mm),尽量… 相似文献
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通过对静电复印机、激光打印机、针式打印机等办公印刷设备工作原理和构造的介绍,分析这些设备形成的各种痕迹,及其阶段性变化特点,探讨利用阶段性特征判定复印、打印等印刷文件的形成时间 相似文献
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原子印章印文盖印相对时间的检验 总被引:1,自引:1,他引:0
近年来,随着原子印章的广泛应用,涉及原子章印文相对时间方面的检验案件越来越多,由于原子印章具有电脑制作、一次灌油多次使用等特点,检验难度较大,有相当一部分检验案件因受检验条件影响而 相似文献
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Biao Li M.Sc. Feng Bai M.Sc. Huayan Mu M.Sc. Ren Bao B.Sc. 《Journal of forensic sciences》2014,59(3):793-799
Inkpad seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, three different brands of inkpads and four different types of paper were used to make diachronic samples of the seals. A double‐solvent extraction method was employed to date the inkpad seals by comparing extraction rates with inks of known age. Cyclohexane was selected as a weak solvent, and chlorobenzene was selected as a strong solvent. After testing, curves were created to show the relationship between the extraction percentage of ink and the date of the seals. The experimental results showed that the extraction rate method was applicable for the relative dating of inkpad seals in some cases where the seal was placed on the document within 6 months. 相似文献
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Biao Li M.Sc. 《Journal of forensic sciences》2014,59(5):1403-1409
Seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, thirty‐seven different brands of stamp‐pad inks and three different types of paper were used to make diachronic samples of the seals. The volatile components of stamp‐pad ink were determined, and the stamp‐pad ink was classified by gas chromatography with a flame ionization detector. Calibration curves were created to show the relationship between the content of volatile stamp‐pad ink components and the age of stamp‐pad ink entries stored under natural aging, UV‐induced aging, and heating aging conditions. The experimental results showed that GC was useful in the analysis of stamp‐pad ink and applicable for determining the relative age of stamp‐pad ink entries in some cases where the seal was placed on the document within 3 months. 相似文献
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In many criminal and civil cases, some questioned documents are written with iron gall ink. Determining the date when an iron gall ink entry was written can be important to assess the authenticity of a document. A dissolution‐diffusion method was successfully employed to draw aging curves of iron gall ink entries stored in controlled conditions over 40 months. Calibration curves were created to indicate the relationship between the average dissolution‐diffusion rate of ink components and the age of ink entries stored under natural aging conditions. As preliminary findings of this study, the mixed solution of dimethyl formamide (DMF) and anhydrous ethanol was suitable to dissolve the dye of iron gall ink strokes made at different time. It was also determined that brands of iron gall inks, types of paper, and thickness of iron gall ink strokes had varying impacts on estimating the dates of iron gall ink strokes. 相似文献
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