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…     

新型粉末状荧光502熏显手印荧光波段研究

目的运用新型粉末状荧光502可一步显现非渗透性光滑客体表面潜手印。为了选择最佳的激发光源和滤光镜来观察熏显后荧光效果,本文对该粉末的荧光性能进行研究。方法使用荧光光谱仪对新型粉末状荧光502进行激发光谱和发射光谱的测试,进而选择合适的激发光源及滤光镜来进行观察和拍照。结果新型粉末状荧光502的光谱范围较宽,在波长为235nm~580nm范围内均可进行激发,具有广谱性,其中对波长在530nm附近的激发光具有最大峰值,即荧光强度最大,对450nm和360nm附近的光也具有很高的吸收峰值,斯托克斯偏移量为45nm。宏观验证实验表明,在仪器分析所得的范围内,显现出的手印效果均较好。结论运用该粉末在熏显手印后可以在紫外、紫光、蓝光、黄光、绿光范围内进行激发,斯托克斯偏移大,荧光亮度高,在观察荧光效果时能够很好的消除背景荧光的干扰,也便于选择滤光镜。手印荧光效果除了受到熏显物质荧光性能的影响外,还与激发光源的品质、滤光片的透过性能以及检材固有的发光特点、客体表面性质有关。     

上转换发光材料显现指纹技术的研发与应用展望

上转换发光,是指长波长的光辐射转换为短波长的光辐射的过程,对非渗透性客体上背景有荧光或图案花纹干扰的手印显现,是实际案件中经常遇到的难题,常规荧光显现方法效果较差,而上转换发光对此有巨大的潜力。本文对上转换发光材料在疑难背景上手印显现的原理、条件、现状以及未来发展方向进行了系统的阐述。     

新型荧光502粉末与502胶＋荧光染色显现潜在手印的比较

目的对新型荧光502粉末显现非渗透性光滑客体表面潜手印的一步荧光502显现新技术和传统502胶水熏显＋荧光染料染色显现手印技术进行比较研究。方法比较实验研究,对荧光502粉末和502胶水使用同一自动熏显柜先后进行熏显,荧光502粉末熏显结束后直接在蓝光灯下激发进行观察和拍照;502胶水在熏显完成和聚合物完全固化后使用罗丹明6G和BBD溶液进行荧光染色,再进行光致荧光照相。结果一步熏显和二次染色的显现效果基本相同,但两者的显现效果也因检材性质和遗留时间的不同而存在一些差别。结论新型荧光502粉末可以作为一种显现非渗透性光滑客体表面上潜手印的常用方法,尽管新方法对某些客体的显现效果并不好,但对大多数客体来说,其显现效果并不弱于二次染色的方法,并且使用新型荧光502粉末进行一步熏显不会引入有机溶剂,不会引起502聚合物的溶解或造成破坏,确保了纹线及其细节特征不被损坏,也避免了染色后因漂洗不当使手印纹线被冲掉的可能,还不会破坏脱落细胞等生物检材。     

新型荧光502粉末与502胶+荧光染色显现潜在手印的比较

目的 对新型荧光502粉末显现非渗透性光滑客体表面潜手印的一步荧光502显现新技术和传统502胶水熏显+荧光染料染色显现手印技术进行比较研究.方法 比较实验研究,对荧光502粉末和502胶水使用同一自动熏显柜先后进行熏显,荧光502粉末熏显结束后直接在蓝光灯下激发进行观察和拍照;502胶水在熏显完成和聚合物完全固化后使用罗丹明6G和BBD溶液进行荧光染色,再进行光致荧光照相.结果 一步熏显和二次染色的显现效果基本相同,但两者的显现效果也因检材性质和遗留时间的不同而存在一些差别.结论 新型荧光502粉末可以作为一种显现非渗透性光滑客体表面上潜手印的常用方法,尽管新方法对某些客体的显现效果并不好,但对大多数客体来说,其显现效果并不弱于二次染色的方法,并且使用新型荧光502粉末进行一步熏显不会引入有机溶剂,不会引起502聚合物的溶解或造成破坏,确保了纹线及其细节特征不被损坏,也避免了染色后因漂洗不当使手印纹线被冲掉的可能,还不会破坏脱落细胞等生物检材.     

荧光检验法在朱墨时序鉴定中的应用研究

朱墨时序鉴定一直是文书司法鉴定实践中常见的鉴定项目,也是研究的热点和疑难问题.通过实验研究并结合检案实践,较系统地阐述了视频荧光光谱检验法和显微荧光检验法在朱墨时序鉴定的具体应用,探讨了荧光检验的技术要点.研究表明,荧光检验法（特别是显微荧光检验法）具有普通显微检验法的优点,同时对普通显微检验法中难以观察到的印文或文字色料荧光特性及色料的微观分布状态,具有明显的检验效果,是普通显微检验法有效的补充检验手段.     

用紫外发光技术显现潜在汗液指印

本实验利用266nm短波紫外线激发长波紫外荧光的紫外发光照相技术探测潜在指印。结果表明在短波紫外线激发下,潜在指印在长波紫外区显示很强的固有荧光。利用该发光技术探测潜在指印固有荧光的比率高达69％,远远高于目前通用的氩离子激光等可见荧光方法的3％～22％。     

荧光STR复合扩增试剂盒的评估过程探索

STR复合扩增检验技术是目前法医DNA检验技术中最重要也是最常用的技术种类之一，随着荧光检测技术和毛细管电泳技术的发展，特别是DNA数据库建设中丰要采用STR复合扩增技术进行基因分型，大大拓展了STR复合扩增检验应用范围。与此同时，STR复合扩增检验试剂成为影响检验质量的重要因素，关系到样本检验分型结果，而分型数据是为法庭提供证据的直接依据，     

荧光原位杂交技术在法庭科学DNA检验中的应用

目的运用荧光原位杂交技术结合激光显微切割技术,分离法医物证男女混合样本中的男性细胞和女性细胞,并进行DNA分型。方法通过双色荧光原位杂交,Y染色体标记上绿色信号,X染色体标记上红色信号,在荧光显微镜下识别男性细胞和女性细胞,并通过激光显微切割技术分别获得男性细胞和女性细胞进行DNA分型。结果运用荧光原位杂交技术,能够分别标记法医物证男女混合样本中的男性细胞和女性细胞,并通过激光显微切割技术获得各自的DNA分型。结论荧光原位杂交技术结合激光显微切割技术,可应用于法医物证男女混合样本的检验,提高个体识别能力。     

同步扫描荧光光谱法鉴别原子印油

本文应用同步扫描荧光光谱法,对不同生产厂家及同一厂家不同品牌的原子印油样品进行分析鉴别,依据不同样品同步扫描荧光光谱的特性,确定了较佳的实验条件.在普通荧光光谱法分析的基础上,进一步提高了检验分辨率,达到了区分不同样品的目的,为全面利用荧光光谱法区分鉴别原子印油提供了科学依据.     

Determination of the Sequence of Intersecting Lines Between Toners and Seals by Laser Fluorescence Microscope

Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing.     

Fluorescence test to identify deep smokers

The lungs of deep smokers contain large numbers of alveolar macrophages with pigment granules in the cytoplasma that are demonstrable by means of fat stains and a distinct green-yellow inherent fluorescence at a wave length range of 350-450 nm. Systematic examinations to test the eluting effect of different solvents on the substances contained in the smoker cells revealed that only extraction in the polar solvent tetrahydrofurane and Folch's solution leads to a reduction of the inherent fluorescence of the pigment granules. Centrifugation of cell or tissue specimens of smoker lungs with Folch's solution results in the fluorescent substances passing into the chloroform phase of the extracting medium, which fluoresces milky-orange-green at a wave length of 366 nm under an ultraviolet lamp. As the fluorescence test is also independent of the degree of freshness of the corpse, extraction of the cell sediments of only a few milliliters of expressed lung tissue fluid or lung tissue mash allows to quickly establish a dead person's smoking habits to help identify the deceased.     

Fluorescence spectra and images of latent fingerprints excited with a tunable laser in the ultraviolet region

Fluorescence spectra of sebum-rich latent fingerprints were studied with a tunable laser for non-destructive fingerprint detection without chemical treatment. The tunable laser consists of a nanosecond pulsed Nd-YAG laser and an optical parametric oscillator (OPO) crystal. The fluorescence spectra and images were measured at various excitation wavelengths in the ultraviolet region by the time-resolved fluorescence method. We have previously reported that a typical fluorescence spectrum of fingerprints consists of two peaks located at c. 330 and 440 nm. In order to determine the wavelength of optimal excitation, excitation spectra were measured at wavelengths ranging from 220 to 310 nm. The fluorescence intensity of the 330 nm peak became maximal with excitation at 280 nm. The images of latent fingerprints on white papers were also measured and the clearest image was obtained with excitation at 280 nm. The influence of continuous irradiation on the fluorescence of fingerprints was measured at the optimal excitation wavelengths. The 330 nm peak was strong at first and decreased with continuous irradiation, whereas the 440 nm peak, which was weak at first, increased gradually.     

数码照相机与视频荧光鉴别仪的物证检验应用比较

索尼SONY WVC-CD300数码照相机与SYJ-5型视频荧光鉴别仪应用在文件检验时,视频荧光鉴别仪部分功能可用 该种数码照相机代替,各具特色。     

Fluorescence of 1,2‐Indanedione with Amino Acids Present in the Fingerprint Residue: Application in Gender Determination

1,2‐indanedione is used for latent fingerprint visualization on porous surfaces. In this paper, fluorescence spectra of 1,2‐indanedione after reacting with 21 individual amino acids present in latent fingerprints residue were measured in water‐methanol solutions. The fluorescence intensity depends on the amino acid used, while the fluorescence peak does not change much. The concentration of amino acids in fingerprint residue in females is almost the double of their concentration in males. This property combined with fluorescence of 1,2‐indanedione‐amino acids compounds is used for gender determination, by comparing the fluorescence intensity peaks in the same experimental conditions. In this preliminary study, the fluorescence signal from the samples representing females was almost two times the signal for samples representing males. In addition to the reduction by almost 50% of the number of suspects in a criminal research case, these results could be helpful in gaining some knowledge about the papillary residue composition.     

Preliminary Study on Determining the Sequence of Intersecting Lines by Fluorescence Technique

The determination of the sequence of intersecting lines is an important part of questioned document examinations. A fluorescence technique was used to determine the sequence of heterogeneous intersecting lines produced using inkpad ink, stamp‐pad ink, ballpoint pens, gel pens, fountain pens, colorants of carbon paper, photocopiers, laser printers, and inkjet printers. A SteREO Discovery.V20 equipped with the ZEN Blue Lite software was chosen to perform the tests.As the results obtained from the study were positive under most conditions, the fluorescence technique was found to be very successful in determining the sequence of intersecting lines from ballpoint pen, gel pen, fountain pen, photocopier, laser and inkjet printers, and inkpad inks. The method was also successful in determining the sequence of intersecting lines from ballpoint pen, photocopier, laser printer, and stamp‐pad inks under most conditions. The technique was not successful in determining the order of crossing lines blending together.     

Effect of Heat on the Fluorescence Properties of Tooth‐Colored Restorative Materials and Their Forensic Implications

During antemortem and postmortem comparison of dental records of carbonized victims, restorations may be part of such records. The objective of this study was to evaluate the effect of heat on the fluorescence behavior of contemporary tooth‐colored restorative materials and natural tooth structure when subjected to range of temperatures, using illumination with 405 nm wavelength light. A total of 132 human extracted teeth restored with tooth‐colored restorative materials were exposed to heat (200, 500, 900, 1200°C) in an oven for 30 min. Samples were imaged before and after heat treatment. All tooth‐colored restorative materials underwent changes in color and in fluorescence properties, at each of the temperatures used. Resin‐based restorative materials still fluoresced at 200°C, and at 500°C underwent major color changes due to volatilization of resin. Materials containing inorganic fluorophores still fluoresced at 900°C, while at 1200°C, none of the materials tested in this study showed any fluorescence.     

The Effect of Time on Bone Fluorescence: Implications for Using Alternate Light Sources to Search for Skeletal Remains

Bones fluoresce when exposed to certain wavelengths of shortwave light, and this property can be useful in locating and sorting skeletal remains in forensic contexts. The proteins in bone collagen are largely responsible for its fluorescent properties, but these proteins degrade and denature over time. This study examined the fluorescence of bones from four temporal groups (recent, semi‐recent, ancient, and historic) ranging from 0 to 1064 years before present. Specimens were photographed under 490 nm wavelength light, and fluorescence was quantified by converting intensity to a gray scale value based on the RGB color model using ImageJ^® software. Significant (p < 0.05) differences were found in mean fluorescence between all four temporal groups, and a 0.324 coefficient of correlation indicates a significant (inverse) relationship between fluorescence and time. Bone fluorescence decreases with time, but some fluorescence is retained even in older samples. Fluorescence can therefore be reliably used in many modern skeletal remains searches.