排序方式: 共有119条查询结果,搜索用时 578 毫秒
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目的用基于银胶的表面增强拉曼光谱技术检验蓝色签字笔字迹。方法取4种常见不同牌号的蓝色签字笔在其字迹上滴加微量银胶,用显微共焦拉曼光谱仪进行检验。结果不同品牌的蓝色签字笔字迹的表面增强拉曼光谱不同。结论基于银胶的表面增强拉曼光谱技术可用于纸张上蓝色签字笔字迹的检验。 相似文献
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Stephanie Houlgrave M.F.S. Gerald M. LaPorte M.S.F.S. Joseph C. Stephens M.S.F.S. Justin L. Wilson B.S. 《Journal of forensic sciences》2013,58(3):813-821
A novel approach for the analysis of inkjet inks is being reported. A time‐of‐flight mass spectrometer, coupled with a Direct Analysis in Real Time (DART?) ion source (AccuTOF? DART?), was used to determine if inkjet inks from various manufacturers and models of printers could be reliably differentiated, characterized, and identified. A total of 217 ink standards were analyzed. As inkjet printing often involves the use of multiple colors (e.g., cyan, magenta, yellow, and black) to form an image or text, two different approaches to creating a library of standards and sampling methods were evaluated for implementation in a standard operating procedure. This research will show that a microscopic examination of the region of interest is requisite to identify what colors were utilized during the printing process, prior to comparing with known standards. Finally, blind testing was administered with 10 unknown samples to assess the validity and accuracy of the methodology. 相似文献
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在文书检验中,朱墨交叉顺序的判定一直是一个常见、重要的内容,对于鉴别文书的真伪具有决定性的重要意义。近年来,在科研和检案实践中发现,正确区分印章印文与书写文字的先后顺序,应掌握以下几个基本环节:有统一的技术规范作指导;检验设备应当满足技术规范要求;对字迹和印文色料与纸张结合方式进行检验;检验方法不能单一,应用多种方法相互对照应证;客观评价阳性反应的出现率和排除假阳性反应的干扰。 相似文献
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王永泉 《中华女子学院山东分院学报》2001,(1):60-62
我国证券交易税种从理论上包括所得税、行为税、印花税等几大类,但实际操作上只有印花税一种,税种单一,税制不完备,已严重地阻碍了证券市场的规范发展和健康成长.在新世纪证券市场"规范中发展"的前提下,如何在适当时机推行证券税制改革,是证管部门、金融机构和每一个投资者都应该关心并努力去解决的问题. 相似文献
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Kai‐kai Li Ph.D. 《Journal of forensic sciences》2019,64(3):897-906
In document examination, it is of great importance to determine the composition of seal ink with different imprint times, and spectroscopic methods are widely used today. In this research, the diffusion of seal inks from three different brands on the same type of paper is monitored in situ by microinfrared spectroscopy and microinfrared imaging technology. The area of the absorption peak at 1743 cm?1 gradually decreases with increasing diffusion time. The diffusion kinetics of seal ink on paper are also studied by analyzing the infrared spectra of seal inks at the same measuring point with different diffusion times. The research provides a basic study in understanding the diffusion behavior of seal ink on paper over short time spans. 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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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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In this study, the potential of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectral imaging as a technique to determine the sequence of line crossings was examined. The technique was successful in determining the sequence of heterogeneous line intersections produced using ballpoint pens and laser printers. By imaging at characteristic frequencies, it was possible to form spectral images showing the spatial distribution of the materials. By examining the spectral images from the inks, it was possible to determine whether the ink was above or below the toner. In blind testing, ATR-FTIR spectral imaging results were directly compared to those obtained by eight experienced forensic document examiners using methods regularly employed in casework. ATR-FTIR spectral imaging was shown to achieve a 100% success rate in the blind tests, whereas some incorrect sequence determinations were made by the forensic document examiners when using traditional techniques. The technique was unable to image ink-jet printing, gel pens, roller ball pens, and felt-tip pens, and was also unable to determine the sequence of intersecting ballpoint pen lines. 相似文献