Research of the surface oxide film on anodizing Ni-Cr porcelain alloy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the shape, thickness and oxide percentage of major metal element of oxide film on Ni-Cr porcelain alloy after anodizing pretreatment.</p><p><b>METHODS</b>10 samples were made and divided into 2 groups at random. Then after surface pretreatment, the oxide films of two samples of each group were analyzed using electronic scanning microscope. The rest 3 samples were measured by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES).</p><p><b>RESULTS</b>Lightly selective solution appeared because the different component parts of the alloy have dissimilar electrode, whose dissolve velocity were quite unlike. The sample's metal surface expanded, so the mechanical interlocking of porcelain and metal increased bond strength. The thickness of oxide film was 1.72 times of the control samples. The oxide percentage of major metal elements such as Cr, Ni and Mo were higher, especially Cr. It initially involved the formation of a thin oxide bound to the alloy and second, the ability of the formed oxide to saturate the porcelain, completing the chemical bond of porcelain to metal.</p><p><b>CONCLUSION</b>The method of anodizing Ni-Cr porcelain alloy can easily control the forming of oxide film which was thin and its surface pattern was uniform. It is repeated and a good method of surface pretreatment before firing cycle.</p>

The development and changes of pressure of putrefactive gas in cadaveric enterocelia in spring and its forensic application / 法医学杂志

OBJECTIVE@#To study the development and changes of pressure of putrefactive gas (PPG) in cadaveric enterocelia in spring, and to explore its application in estimation of postmortem interval (EPI).@*METHODS@#57 goats were divided into 2 groups according to means of death, on land or in water. Celiac PPG were observed timely and systematically.@*RESULTS@#The development of PPG in cadaveric enterocelia, which can be divided into raising phase, peak phase, and declining phase was observed, and a model to estimate postmortern interval by changes of PPG was founded.@*CONCLUSION@#Measuring PPG in cadaveric enterocelia could be used in forensic EPI.