扫描电镜/能谱法对92式手枪射击残留物检出率与遗留时间相关性的研究

目的研究92式手枪射击残留物检出率与遗留时间的相关性,为射击时间的推断提供依据。方法实验人员使用92式手枪分别射击1枪和3枪,射击后分别在0.5h内,24h,48h,72h,120h,168h,对实验人员的手部及衣袖袖口处进行射击残留物的提取,利用扫描电镜和能谱仪对射击残留物进行检验。结果射击人的手部和衣袖会附着大量的射击残留物,随着时间的推移,手部的残留物数量急剧减少,24h（射击1枪）、72h（射击3枪）后不能检测到枪击残留物。而衣袖处120h（射击1枪）、168h（射击3枪）内均可检测到射击残留物,且射击残留物的检出率与遗留时间呈负相关性。结论随着遗留时间的增加,衣袖处射击残留物检出率递减,对涉枪案件中射击时间的判断有一定的参考价值。     

SEM检验漆膜厚度鉴别同种颜色的汽车油漆

目的研究扫描电子显微镜测量漆膜厚度的方法对颜色相近的汽车油漆的区分能力。方法应用扫描电子显微镜对不同汽车厂家生产的12块蓝色油漆进行总厚度及分层厚度测量,并对所得数据进行t检验分析。结果在所有两两比对的66组样品对中,在置信度为95％时,用总厚度及分层厚度进行区分,区分率达到100％。结论用扫描电子显微镜微观测量油漆样品总厚度及分层厚度的方法,可对颜色相近的汽车油漆进行有效区分。     

Transfer and Distribution of Gunshot Residue through Glass Windows

Research into the deposition patterns of primer gunshot residue (GSR) beyond a primary target was previously nonexistent. This study aimed to determine the deposition patterns of GSR once a bullet passed through an initial target and continued on its path into additional targets. Multiple repetitions were performed to assess the GSR deposition patterns after a bullet was shot through a closed window into either a dummy or a wall within an enclosed room. Samples were taken from both the primary and secondary target holes as well as from nontarget areas. Significant amounts of GSR were found on all samples. The results show that GSR continues to be deposited along the path of the bullet after passing through a primary glass target. These findings reiterate the lack of probative value in collecting GSR samples from gunshot victims even if they are in an enclosed area separate from the shooter.     

用SEM观察真皮浅层微小刺伤的研究

本文报道了一种用酶水解表皮与真皮的连接,然后用扫描电镜观察微小损伤在真皮乳头层的损伤特点的新方法。研究结果表明,这种方法有利于微小刺伤的鉴定,并提供一些具体的鉴定指标。     

Detection and classification of composite resins in incinerated teeth for forensic purposes

The great demand for esthetic restorations has resulted in placement of large numbers of composite resin fillings. The popularity of these materials is reflected in the quantity and variety of resin brands currently on the market. The ability to distinguish resin brands can aid in positive identification of burn victims, assuming that appropriate dental records exist. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) was used to characterize the structure and composition of 10 modern resins. The structure of each resin was unique to manufacturer, and elemental analysis allowed separation into distinct groups. These 10 resins were also placed in extracted teeth and incinerated at 900 degrees C for 30 min, simulating near cremation conditions. The resins were identifiable by SEM/EDS after incineration, and the elemental composition remained almost unchanged. The data produced are immediately useful for resin identification in forensics, and comparative analysis can be readily performed using standard equipment. This work represents the initial stage of database generation.