刑事技术
刑事技術
형사기술
FORENSIC SCIENCE AND TECHNOLOGY
2015年
1期
8-11
,共4页
手印%荧光粉末%二氧化钛
手印%熒光粉末%二氧化鈦
수인%형광분말%이양화태
fingerprints%fluorescent powder%titanium dioxide
目的:使用荧光染料包覆纳米二氧化钛颗粒,制备具有荧光效果的纳米二氧化钛粉末材料,并探索应用纳米二氧化钛荧光粉末显现潜在手印的方法。方法使用实验室合成的二酰亚胺染料与纳米二氧化钛微粒按照一定质量比混合制备形成荧光粉末,通过扫描电子显微镜对其进行表征,观察颗粒结构特征。在玻璃、瓷砖、透明塑料片、彩色塑料包装、易拉罐5类非渗透性客体上捺印手印,观察纳米二氧化钛荧光粉末对不同非渗透性客体上新鲜潜手印的显现效果。分别在5种客体上制作遗留时间为1、4、7、15d 的手印样本,考察遗留时间对纳米二氧化钛荧光粉末显现自然陈旧手印效果的影响。将新鲜手印置于标准大气压100℃条件下分别加热1~72h,使用纳米二氧化钛荧光粉末显现,考察其对高温老化手印的显现效果。结果纳米二氧化钛荧光粉末为粒径100~200nm 的圆形颗粒;在蓝绿光激发下可发出较强的荧光,能显现多种非渗透性客体上的新鲜手印,与背景反差明显并且能显著降低复杂背景对手印纹线的影响;显出新鲜手印中80%以上具有鉴定条件。纳米二氧化钛荧光粉末对遗留15d以内的陈旧手印仍具有较好的显现效果。100℃高温环境对手印显现效果没有明显影响。结论纳米二氧化钛荧光粉末经济、环保,显现操作简单,易于推广。
目的:使用熒光染料包覆納米二氧化鈦顆粒,製備具有熒光效果的納米二氧化鈦粉末材料,併探索應用納米二氧化鈦熒光粉末顯現潛在手印的方法。方法使用實驗室閤成的二酰亞胺染料與納米二氧化鈦微粒按照一定質量比混閤製備形成熒光粉末,通過掃描電子顯微鏡對其進行錶徵,觀察顆粒結構特徵。在玻璃、瓷磚、透明塑料片、綵色塑料包裝、易拉罐5類非滲透性客體上捺印手印,觀察納米二氧化鈦熒光粉末對不同非滲透性客體上新鮮潛手印的顯現效果。分彆在5種客體上製作遺留時間為1、4、7、15d 的手印樣本,攷察遺留時間對納米二氧化鈦熒光粉末顯現自然陳舊手印效果的影響。將新鮮手印置于標準大氣壓100℃條件下分彆加熱1~72h,使用納米二氧化鈦熒光粉末顯現,攷察其對高溫老化手印的顯現效果。結果納米二氧化鈦熒光粉末為粒徑100~200nm 的圓形顆粒;在藍綠光激髮下可髮齣較彊的熒光,能顯現多種非滲透性客體上的新鮮手印,與揹景反差明顯併且能顯著降低複雜揹景對手印紋線的影響;顯齣新鮮手印中80%以上具有鑒定條件。納米二氧化鈦熒光粉末對遺留15d以內的陳舊手印仍具有較好的顯現效果。100℃高溫環境對手印顯現效果沒有明顯影響。結論納米二氧化鈦熒光粉末經濟、環保,顯現操作簡單,易于推廣。
목적:사용형광염료포복납미이양화태과립,제비구유형광효과적납미이양화태분말재료,병탐색응용납미이양화태형광분말현현잠재수인적방법。방법사용실험실합성적이선아알염료여납미이양화태미립안조일정질량비혼합제비형성형광분말,통과소묘전자현미경대기진행표정,관찰과립결구특정。재파리、자전、투명소료편、채색소료포장、역랍관5류비삼투성객체상날인수인,관찰납미이양화태형광분말대불동비삼투성객체상신선잠수인적현현효과。분별재5충객체상제작유류시간위1、4、7、15d 적수인양본,고찰유류시간대납미이양화태형광분말현현자연진구수인효과적영향。장신선수인치우표준대기압100℃조건하분별가열1~72h,사용납미이양화태형광분말현현,고찰기대고온노화수인적현현효과。결과납미이양화태형광분말위립경100~200nm 적원형과립;재람록광격발하가발출교강적형광,능현현다충비삼투성객체상적신선수인,여배경반차명현병차능현저강저복잡배경대수인문선적영향;현출신선수인중80%이상구유감정조건。납미이양화태형광분말대유류15d이내적진구수인잉구유교호적현현효과。100℃고온배경대수인현현효과몰유명현영향。결론납미이양화태형광분말경제、배보,현현조작간단,역우추엄。
Objective To explore a new approach for developing latent fingerprints by using fluorescent titanium dioxide nano-particles. Methods Titanium dioxide nano-particle was coated with fluorochrome and the morphological feature was observed by scanning electron microscope (SEM). Five kinds of non-porous surfaces, including glass, transparent plastic, colored plastic, tile, and can were used in this experiment. Fingermarks were deposited after wiping fingers over the forehead in succession and then pressing them onto substrates. The fluorescent powder was applied to fingermarks deposited on the surfaces. The fingermarks were stored for 1, 4, 7 and 15d or heated at 100℃ for 1~72h before treated. The samples were then observed in the luminescence mode using a Polilight alternative light source with the emission set at excitation wavelength of 515nm. Results Observation of the prepared powders using SEM shows that the dye-coated particles’ size varies from 100 to 200nm in diameter. The fluorescent dye/TiO2 powder was light pink particles under white light. Illuminated at 515nm, TiO2 particles coated with fluorescent dye exhibited strong fluorescence. When latent fingerprints detected with this fluorescent powder, particles could be selectively adhered to the latent fingerprint deposit. Fingerprints developed with fluorescent dye/TiO2 showed strong orange-red luminescence and clear details of ridge. On several nonporous substrates, the new powder gave a lower background and thus better contrast in developed fingerprints. Colored surfaces were also tested and the results demonstrated the advantages of the fluorescent powder with better contrast. Storage time of fingerprints did not make significant difference in the quality of developed fingerprints on glass. The fluorescent dye/TiO2 powder gave satisfactory results when applied to 15-day fingerprints retained on substrates of glass, transparent plastic and cans. The enhancement for detail was slightly less than that with fresh prints, but the powder still revealed clear images. While for colored plastic, the image of older marks (>7d) developed by fluorescent dye/TiO2 powder showed less ridge details. Fingerprints on tile developed by fluorescent dye/TiO2 powder showed strong fluorescence, but the image of older marks became indistinct over time. When the fingerprints heated for 1~72h were developed with the fluorescent dye/TiO2 powder, the quality of developed fingerprints was as for fresh fingerprints. However, a slight reduction in fluorescence intensity was observed towards the 72h setting as fingerprint deposit dried out and lost its stickiness. Conclusions Fluorescent nano-dye/TiO2 powder is a new developing method that can be applied to develop fresh as well as aged latent fingerprints on nonporous substrates without background color requirements. This method is very sensitive and selective; the fluorescence can be excited at 515nm and observed through an orange-red long-pass filtering barrier. This fluorescent powder is easy to use, low-cost and non-toxic, it can be used for developing latent fingerprints.