No abstract

Keywords: GSR SEM/EDX NAA Chemical ballistic Scientific Police of Algeria a b s t r a c tThis work is realized in view to determine appropriate techniques for the revelation of mineral gun shoot residues. Picked up from the crime scene, these indicial traces are used as material proofs for helping and guiding judicial investigations. As achievement of this process, two (02) technics were employed for mineral gun shoot residues, namely; Neutron Activation Analysis, and scanning electron microscopy/EDX. Samples of metallic powder residue were realized after several shoots by different kind of weapons with local and foreign ammunitions. So, this study was undertaken to develop chemical ballistic specialty in order to improve forensic investigations and drive benefit to Technical and ScientificPolice of Algeria to be use for judicial investigation.It turns out that the SEM/EDX method is more adequate to this type of investigation, despite the high sensitivity of the NAA. This is stated; NAA remains a complementary methods.

It has been found that the silicon nanowires modified with noble metals can be used to fabricate an effective H 2 gas sensor in the present study. The preparation and surface modification of silicon nanowires (SiNWs) were carried out by chemical methods. The morphology of the silicon nanowires unmodified and modified with nanoparticles of platinum, palladium, silver and gold was investigated using scanning electron microscopy (SEM). The chemical composition of the silicon nanowire layers was studied by secondary ion mass spectroscopy (SIMS) and energy dispersive X-ray analysis (EDX). The structures of type metal/SiNWs/p-Si/Al were fabricated. The electrical characterization (I-V) was performed in primary vacuum and H 2 at different concentrations. It was found that the metal type used to modify the SiNWs strongly influenced the I-V characteristics. The response of these structures toward H 2 gas was studied as a function of the metal type. Finally, the sensing characteristics and performance of the sensors were investigated.

No abstract