显微光谱成像技术在汽车油漆截面检验中的应用

目的对汽车多层油漆的横截面进行分层和比对研究。方法运用显微光谱成像技术对收集的12个省市623个汽车漆片样本进行分层,并对截面结构相同或相似的油漆样本进行了区分。结果 623个油漆样本均可以分层,分析出漆层为两层及以上的油漆样本数占总数的87.26%;截面结构相同或相似的油漆样本能够多层同时区分。结论该方法具有科学及实用价值,检验结果可靠,可见光谱成像技术完全可运用拓展到微量物证的检验中。     

激光剥蚀电感耦合等离子体质谱技术检测车辆油漆金属元素

目的建立车辆油漆的激光剥蚀电感耦合等离子体质谱（laser ablation inductively coupled plasma mass spectrometry,LA—ICP—MS）分析方法。方法对38种车辆油漆样品采用激光剥蚀,电感耦合等离子体质谱进行测定,通过各油漆样品本含有金属元素种类和金属元素响应相对比值的差异对油漆样品进行区分。结果38种样品中有30种可直接依据所含金属元素种类的差异进行对其进行区分,其余8种依据元素间响应值比值的差异进行区分,方法重现性良好,精密度（RSD）小于10％。结论所建立的LA—ICP—MS方法简便快速、精密度良好、对样品微损,适用于法庭科学对车辆油漆的检测。     

显微分光光度法区分油漆样品的研究

本文采用色度学和统计分析的方法,对用显微分光光度法区分油漆样品进行了研究。     

汽车罩光漆的ATR-FTIR法检验

目的通过对油漆样品罩光漆成膜物质的检验以区分不同汽车厂家的油漆样品。方法采用衰减全反射红外光谱法（Fourier Transform Infrared Spectroscopy Attenuated Total Reflection Spectroscopy,ATR-FTIR）研究15个汽车厂家提供的356份油漆样品的罩光漆成膜物质。结果在所有油漆样品中,丙烯酸漆出现的频率最高,氨基漆出现的频率最低;在所有厂家中,使用丙烯酸漆的厂家最多,使用氨基氨酯混合漆的厂家最少;在使用相同罩光漆的不同厂家的油漆样品中,通过比较红外谱图可以对样品进一步区分。结论 ATR-FTIR法能够在一定程度上区分不同汽车厂家的油漆样品,从而大大缩小侦查范围,对于涉车案件的快速侦破具有非常重要的作用。     

裂解气相色谱-质谱法和红外光谱法对红色汽车油漆的比较分析

目的应用裂解气相色谱-质谱法（Py-GC/MS）和红外光谱法（IR）鉴别3种红色汽车油漆,通过二者的比较,考察Py-GC/MS法在微量物证油漆鉴定中的适用性。方法取适量固体样品直接检测。IR检测条件：红外显微镜,透射模式,光阑尺寸100μm×100μm,检测范围为4000-675cm-1。Py-GC/MS检测条件：裂解温度：550℃,裂解时间：0.20min。HP-5MS色谱柱,分流比80∶1;升温程序：起始温度为40℃,保持1 min,然后以8℃/min升至300℃,保持1 min。质谱采用EI源,扫描范围：29~350 amu。结果 3种红色汽车油漆的红外光谱、裂解图谱均能相互区分。通过裂解产物,能获得更多油漆主要成膜物质的成分信息。结论在样品量许可的条件下,应在红外光谱的检测基础上,进一步使用裂解气相色谱-质谱方法来对汽车油漆进行检测,通过互相验证,获得更准确、可靠的油漆鉴定结果。     

表层微量油漆颜色的统计分析

本文介绍一种采集油漆的新方法,即多元统计取样法。采用显微分光光度计测量表层油漆的颜色,得出统计平均值后计算总色差,结果准确,不受油漆层数的影响,减小了受检样品量、人为或非人为因素的影响,提高了微量油漆颜色检测的准确度。     

汽车风挡玻璃的鉴别方法研究

目的研究油浸法和X射线荧光光谱法对汽车风挡玻璃的鉴别能力。方法应用油浸法对30个风挡玻璃样品进行折射率测试，并将所得数据进行t检验分析。对不能区分的样品再用X射线荧光光谱进行元素成分分析。结果30个样品共组成的435对中，折射率t检验在置信度959／5时区分427对，其余8对通过元素成分实现区分。结论折射率测试和元素分析相结合，可对常见汽车风挡玻璃进行有效区分。     

油浸法鉴别汽车后视镜玻璃的研究

目的研究油浸法对汽车后视镜玻璃的鉴别能力。方法应用油浸法对20种汽车后视镜玻璃进行折射率值测定并用t检验法对数据进行处理。结果在置信度为95％时，20个后视镜玻璃样品的区分率为97．9％。结论油浸法对汽车后视镜玻璃有很好的区分能力，而且使用样品量少，可以达到微克级，是一种鉴别后视镜玻璃的有效方法。     

同色电工胶带的光谱成像技术检验

目的研究同种颜色电工胶带的区分方法。方法应用光谱成像技术对同色（选取红、黄、蓝、绿4种颜色）不同品牌的电工胶带进行区分。结果蓝色电工胶带的区分率最高,达到99.0%,红色、绿色、黄色样品的区分率相差不大,分别为94.3%、93.8%及93.3%。结论光谱成像技术可以实现同种颜色电工胶带的快速区分,从色度学角度为法庭科学领域电工胶带物证的区分提供了一种新的方法。     

透明胶带的厚度检验

目的研究不同品牌透明胶带的区分方法。方法利用测厚仪对35种不同品牌透明胶带的厚度进行检验,并对所得数据进行统计分析。结果 35种品牌透明胶带组成的595组样品对中有458组可以区分,区分率为77.0%。结论厚度检验法能够在一定程度上区分不同品牌的透明胶带,厚度检验结果可与化学成分检验相互佐证,使得鉴定结论更加准确可靠,为法庭科学领域透明胶带物证的区分提供了一种预检验方法。     

Passport examination by a confocal-type laser profile microscope

The author proposes a nondestructive and highly precise method of measuring the thickness of a film pasted on a passport using a confocal-type laser profile microscope. The effectiveness of this method in passport examination is demonstrated. A confocal-type laser profile microscope is used to create profiles of the film surface and film–paper interface; these profiles are used to calculate the film thickness by employing an algorithm developed by the author. The film thicknesses of the passport samples—35 genuine and 80 counterfeit Japanese passports—are measured nondestructively. The intra-sample standard deviation of the film thicknesses of the genuine and counterfeit Japanese passports was of the order of 1 μm The intersample standard deviations of the film thicknesses of passports forged using the same tools and techniques are expected to be of the order of 1 μm. The thickness values of the films on the machine-readable genuine passports ranged between 31.95 μm and 36.95 μm. The likelihood ratio of this method in the authentication of machine-readable Japanese genuine passports is 11.7. Therefore, this method is effective for the authentification of genuine passports. Since the distribution of the film thickness of all forged passports was considerably larger than the accuracy of this method, this method is considered effective also for revealing the relation among the forged passports and acquiring proof of the crime.     

Midsagittal facial tissue thicknesses of children and adolescents from the Montreal growth study.

Knowledge of changes in soft tissue depths during growth and development is important in applied contexts of forensics and dentistry as well as in growth research. In forensics, applications include facial reproductions, video superimpositions, and child aging/progressions. Garlie and Saunders (1) recently published radiographic data from the Burlington Canadian growth study; here, we present data from a mixed longitudinal sample of French-Canadian children and adolescents. Females (N = 159) range in age from 6 to 18 years: males (N = 129), from 6 to 19 years. Cephalometric measurements include nine soft tissue thicknesses, two hard tissue distances (sella-nasion and nasion-menton), and three measures of nasal projection. Several tissue thicknesses are moderately correlated with one another. The majority of thicknesses show significant sex differences by the time of adolescence; nasion and upper labial thicknesses are significantly different by sex at all ages from 6 to 18 years, as are the two hard tissue distances. However, thickness at nasion, as well as at glabella, changes little over time. Thickness at pogonion is variable and differs most between males and females at age 16; the length of the anterior inferior portion of the nose is significantly different between the ages of 6 and 12. Measurements display small and slow changes during development. The greatest average change per year (c. 2 mm/yr) is for a hard tissue measure, nasion-menton. The nasal and mid-philtrum regions have greater age changes than do other soft tissue variables. Much of the variation remains unexplained by changes with age or differences between sexes.     

红外差谱技术用于微量混合油漆的比对检验

对交通事故中的漆片检材进行同一物质比对时,某些情况下难以提取到单一的油漆碎片而是两辆车的油漆混合在一起,给物证比对带来困难。红外差谱技术具有辨别混合物中不同成分的功能,因此可应用于交通事故中混合油漆检材的比对检验。本文对一起交通事故的漆片检材,分别用三种方式提取、制样,用红外光谱仪进行分析,借助红外差谱技术对谱图进行处理,排除混合油漆的干扰。处理后得到的谱图与样本的谱图进行比对,结果显示两者主要官能团吸收峰位置、峰型、峰强度基本一致,可出具比对一致的结论。针对混合油漆检材的比对检验,红外差谱技术可提供支持。     

Reproducibility of facial soft tissue thicknesses for craniofacial reconstruction using cone-beam CT images

The purpose of this study was to evaluate the reproducibility of the soft tissue (ST) thicknesses at 31 landmarks using the cone-beam computed tomography (CBCT) images obtained from 20 adult subjects. Four observers carried out ST thickness measurements using Skull Measure software, and the inter- and intra-observer error rates were evaluated. Only five of 31 landmarks showed significant differences in recorded ST thickness between the observers. When excluding inexperienced observers, only one landmark showed a significant difference between the observers. Regarding the intra-observer reproducibility, the ST thickness measurements at three landmarks showed low correlation coefficients. The results of this study indicate that CBCT images can be used to measure ST thickness with high reproducibility. However, some landmarks need to be redefined to reliably measure ST thickness on CBCT images.     

家兔死后的角膜厚度变化及其与死亡时间的关系

目的探讨家兔死后不同时间角膜厚度变化及其与死亡时间的关系。方法将25只家兔采用空气栓塞的方法处死后,用角膜超声测厚仪分别于死后即刻、2h、4h、8h、12h和24h测量角膜的厚度,所得数据进行统计学处理。结果即刻死亡家兔角膜厚度平均值为（357.10±6.41）μm,死亡24h角膜厚度平均增加（187.52±11.38）μm;4h内,眼睑开启与闭合对角膜厚度的增加无明显影响（F=3.5290,P〉0.05）,8h后随时间延长,眼睑闭合角膜厚度为（429.24±8.80）μm,明显超过眼睑开启角膜平均厚度（421.40±9.53）μm,其差异有显著性意义（F=14.4480,P〈0.05）。眼睑闭合的角膜厚度与死亡时间关系为y=8.2418x＋357.33（相关系数r1=0.8732）;眼睑开启的角膜厚度与死亡时间关系为y=7.3737x＋357.23（r2=0.8578）。结论在一定条件下,家兔死后24h内角膜厚度与死亡时间呈线性相关。     

Analysis and discrimination of architectural paint samples via a population study

This study involved the comparative analysis and discrimination of 964 architectural paint samples collected in the United States and Canada. The samples were evaluated to determine the extent to which randomly collected architectural finishes can be discriminated following standard operating protocols for paint analysis. The study also provides a basis for assessing the significance of a result in which a pair or group are undifferentiated. The techniques utilized were stereomicroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with both backscatter electron imaging (BSI) and energy dispersive spectroscopy (EDS), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). To assess the layer characteristics (e.g., number, color, sequence, thickness), stereomicroscopy was used with FTIR and/or SEM as needed. The use of visual and microscopic evaluations in concert with FTIR resulted in 42 undifferentiated pairs, a discrimination of 99.99%. Adding SEM and Py-GC/MS analysis resulted in further discrimination of 31 pairs, resulting in eleven undiscriminated pairs of samples. At the conclusion of the study, samples that remained undifferentiated proved to originate from the same source. Therefore, no random pairs were indistinguishable at the conclusion of all examinations.     

Mid-facial tissue depths of white children: an aid in facial feature reconstruction

Available facial tissue thickness standards for facial feature reconstruction are based on adult measurements. Mid-facial tissue thicknesses for male and female white adolescents are presented here. Measurements were taken from lateral radiographs produced in an orthodontic practice. Statistical analysis indicates that age, sex, and to some extent, dental occlusion pattern are factors that should be taken into account when attempting facial feature reconstructions.     

Variation in midfacial tissue thickness of African-American children

Forensic anthropologists use facial reconstruction to develop a likeness of an unknown individual in order to generate public interest that may lead to a positive identification. Tissue thicknesses of the face from living persons or cadavers are an essential part of the reconstruction method. The purpose of this study is to add to the growing database of tissue thicknesses along the facial midline of African-American children and to begin to examine the possibility of geographic differences between children of the same ancestral group. Results indicate that significant differences do not exist between males and females or between African-American females from the Midwest and Southeast U.S. Only age was determined to have a significant effect on mean tissue thickness variation, in our sample, with the majority of change occurring in the facial region.     

The random presence of glass and paint on the clothing and footwear of members of the general population: A US baseline survey at various seasons

This study assists the interpretation of glass and paint evidence by filling an existing gap in the background occurrence that reflects the socioeconomic and demographic circumstances in the United States. The collection was performed in a college US city (Morgantown, West Virginia) to determine the effect of the type of clothing worn at different seasons on the presence of glass and paint. Tape lifts and sole scrapings (1038) were collected from 210 participants and up to six clothing and footwear areas per individual. Glass fragments were analyzed via polarized light microscopy (PLM), refractive index (RI), micro-X-Ray fluorescence (μXRF), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), while paint specimens were examined by light microscopy and infrared spectroscopy (μFTIR). Higher occurrences of glass and paint were found in the winter season. The winter collection yielded 10 glass fragments and 68 paint particles, whereas the summer collection resulted in one glass fragment and 23 paint particles. The percentage of individuals with traces varied between seasons; 7% of individuals in the winter and 0.9% in the summer had glass, whereas 36% of individuals in the winter and 19% in the summer bore paint. Lastly, when considering the overall garment and footwear areas, glass was detected in 1.4% of the winter set, compared to 0.2% in the summer collection; paint was found in 9.2% of the winter collection, whereas only 4.2% was found in the summer set. There were no instances where both glass and paint were detected on the clothing and footwear of the same individual.