The Application Of Scanning Electron Microscope(SEM),energy Dispersive X-ray Spectrometer(EDS)in The Identification Of Trace Evidence In Traffic Accidents

With the dramatic improvement of people's living standards,the quantity of motor vehicles and the number of new motor vehicle drivers surging,leading directly to the rapid growth in the number of traffic accidents,the resulting social contradictions become increasingly prominent.Efficient and fair handling of traffic accidents,has become one of the urgent tasks for the guarantee of socialism harmony,social stability and unity.As the trace material evidence is difficult to be found and destroyed,the identification means with high technical content and the identification results with strong scientificity.And it plays a more and more important role in the investigation process of various cases.In the traffic accident,the accident usually occurs suddenly,and the vehicle runs fast,the scene is seriously damage,the traditional evidence and witness testimony then reflects the limitations.The status of trace evidence in the handling of traffic accidents is also increasing.In this paper,hereby made the study of the application of Scanning Electron Microscope(SEM),Energy Dispersive X-ray Spectrometer(EDS)in the identification of traceevidence in traffic accidents.The paper is divided into four parts:The first chapter,theoretical basis and research background.This part is divided into four sections,section one describes the development,theoretical basis and working principle of SEM and EDS;Section two describes the concept,type,characteristics,role and identification methods of trace-evidence,and emphatically pointed out the possible occurrence of trace evidence in traffic accidents;section three introduces the application of SEM / EDS in the identification of trace evidence;section four introduces the main research contents of this paper.The second chapter,test methods and procedures.Introduce the instruments,tools and test methods required for SEM / EDX—Energy Dispersive X-ray Spectrometry,and the basic content of using this method in this paper,to analyze and identify several kinds of common trace material evidence in traffic accidents.The third chapter,test results ? research and discussion.This part is divided into five sections,section one through the analysis of the trace evidence of Paint class,using SEM / EDX to identify the hit-and-run vehicles,this section deals with two cases;section two through the analysis of the trace evidence of Polymer class,using SEM / EDX to analyze and identify the contact happened between the car bodies,this section involves two cases as well;section three through the analysis of the trace evidence of Hair,using SEM / EDX to analyze and assist in the identification of the driver,this section refers to one case.Section four through the analysis of the trace evidence of Polymer class,using SEM / EDX to analyze and assist in the identification of the movement path of the hit-and-run vehicles,this section relates to one case.Section five to reconstruct the traffic accidents by the mutual confirmation of the intercomparison result of SEM/ EDX,this section come down to one case as well.The conclusion and analysis part,through the conclusion of the identification obtained by using the Scanning Electron Microscope,SEM /EDX—Energy Dispersive X-ray Spectrometry to analyze and compare the trace material evidence in the cases,and the analysis of the role it plays in the case of traffic accident handling,to discuss and study the application of Scanning Electron Microscope,SEM / EDX—Energy Dispersive X-raySpectrometry in the identification of trace evidence in traffic accidents.