朱墨时序显微检验的技术要点及应用

朱墨时序鉴定常见的检验方法包括显微检验法、减层法及光谱法等,其中最基础也是最被普遍使用的方法是显微检验法。通过对显微镜检验在朱墨时序鉴定中的技术要点进行讨论,阐述如何通过选择不同的显微镜,调整放大倍率、照明方式、观察方式及运用共聚焦等技术手段达到最佳观察效果和检验图片。总结了朱墨时序显微镜检验所依据的表观特征及其观察和分析要点,希望对朱墨时序鉴定实践起到积极的指导作用。     

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.     

电子政府的网络和信息安全问题思考

电子政府的网络建设和信息安全一直是近年比较热门的话题。政府部门的工作逐步公开了,大部分数据都通过网络流动了,如何保证数据安全和网络系统可靠运行就成了关键。深病毒的影响,大量网络瘫痪,重要信息遭到恶意更改,这些都是电子政府网络信息安全需要解决的问题。本文从如何解决电子政府网络信息安全方面进行多方阐述,提出了一些解决方案。     

基于相差显微镜无损检验头发染色问题研究

为了有效识别犯罪现场提取的黑色头发是否是染色头发,利用OLYMPUSBX51相差显微镜无损观察未染色及几种情况染色的黑色头发。结果表明,黑色头发中染色与未染色、黑色再染黑与白色染黑、染色两周与刚刚染色头发之间在相差显微镜下都存在显著差别。因此,文中基于相差显微镜无损检验方法为法医学鉴定头发染色问题提供了有效的检验方法。     

白鹃梅花蕾及嫩叶显微鉴别

目的 研究白鹃梅花蕾及嫩叶的显微特征,为其生药学鉴别提供依据。方法 采用性状鉴别、显微鉴别方法。结果 白鹃梅食用部位具有独特的性状,其叶、花及花的粉末具有独特的显微特征。结论 白鹃梅花蕾及嫩叶的显微鉴别为其开发利用提供了一项技术参考。     

大鼠尸僵发展过程中肌节长度的变化及其长度测定

目的观察大鼠尸僵发展过程中肌节形态、肌节长度的变化。方法 2 1只大鼠分为 3组 ,每组大鼠分别于死后立即和死后 2h、 4h、 6h、 8h、 12h、 2 4h取材 ,扫描电镜下观察大鼠死后不同时间的肌节形态 ,同时测定肌节长度。结果死后立即取材标本肌原纤维松散 ,纤维间有一定的间隙 ;死后 2h ,肌原纤维间界限模糊 ,出现周期性横纹 ;死后 4h、 6h横纹清晰 ;死后 12h肌原纤维断裂 ,仍可见横纹 ;死后 2 4h肌原纤维断裂、融合。各组大鼠肌节长度与同组立即取材时比较 ,死后 2h、 4h、 6h、 8h均显著变短 (P值均小于 0 0 0 1) ,其中死后 4～ 6h最短 ;死后12h均无显著性差异 (P值均大于 0 0 5 ) ;死后 2 4h ,组 1、组 3无显著性差异 (P值均大于 0 0 5 ) ,组 2差异显著(P值为 0 0 0 7)。结论用扫描电镜测定肌节长度 ,发现肌节长度随尸僵经过时间的延长而发生变化     

Metal objects mapping after small charge explosions. A study on AISI 304Cu steel with two different grain sizes

Evidence of exposure of a metal component to a small charge explosion can be detected by observing microstructural modifications; they may be present even if the piece does not show noticeable overall plastic deformations. Particularly, if an austenitic stainless steel (or another metal having a face-centered cubic structure and a low stacking fault energy) is exposed to an explosive shock wave, high-speed deformation induces primarily mechanical twinning, whereas, in nonexplosive events, a lower velocity plastic deformation first induces slip. The occurrence of mechanical twins can be detected even if the surface is damaged or oxidized in successive events. In the present research, optical metallography (OM) and scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) were used to detect microstructural modifications caused on AISI 304Cu steel disks by small-charge explosions. Spherical charges of 54.5 or 109 g TNT equivalent mass were used at explosive-to-target distances from 6.5 to 81.5 cm, achieving peak pressures from 160 to 0.5 MPa. Explosions induced limited or no macro-deformation. Two alloy grain sizes were tested. Surface OM and SEM evidenced partial surface melting, zones with recrystallization phenomena, and intense mechanical twinning, which was also detected by STM and X-ray diffraction. In the samples' interior, only twins were seen, up to some distance from the explosion impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For forensic science locating purposes after explosions, the maximum charge-to-target distance at which the phenomena disappear was singled out for each charge or grain size and related to the critical resolved shear stress for twinning.     

颅骨骨折断面细微结构的观察研究

作者利用扫描电子显微镜,对颅骨骨折断面上微细结构的形态学特征进行了观察与研究,发现在颅骨骨折断面上有微细的骨折裂线,向断面深部的骨质中延伸,其宽度为5至100um不等,主要分布在颅骨外板内,或外板与板障的交界处.分布于板障内的微细裂线可造成骨小梁横行、纵行和螺旋形骨折.骨折时,骨基质中的胶原纤维束可被分离或断裂,各胶原纤维层可分开.骨内血管可被骨折裂线横断或纵形撕裂,损伤的血管可被从哈佛氏管中拉出.生前骨折时,在微细裂线的深方可清楚见到纤维蛋白网和红细胞相互粘集,死后骨折则未见到此现象.本文还探讨了颅骨骨折发生的机理和推断生前骨折的可能性.     

环境扫描电镜在法庭科学中的应用

介绍了环境扫描电镜中二次电子成像的原理及在非导电样品、含水含油样品、植物及生物样品中的应用.     

尸僵再形成的实验性研究

目的观察尸僵再形成中肌节长度的变化。方法应用扫描电镜测定不同条件下取材的40只大鼠股四头肌肌节长度,判断再僵直的强度。结果死后未破坏的尸僵肌节的长度明显小于尸僵再形成时的长度。结论肌节长度与尸僵强度呈负相关,说明肌节长度可确定尸僵强度,从而为推断死亡时间提供依据。