Search

In this paper, we experimented the glowing and heating phenomenon at the contacts of copper wires, and studied the breeding process, the growing characteristics of copper oxide according to the diameter of copper wires and AC current. The surface structure, crystalline structure, compositions and calory variation of Cu2O that grew at the contacts of two copper wires were analyzed by using scanning electron microscope (SEM), metallurgical microscope, energy dispersive X-ray spectroscopy (EDX) and differential scanning calorimetry (DSC). As these results, we could know that carbonization and oxidation reaction generated on the outside of the oxide, and only oxidation reaction generated in the inside of the oxide

There are many electrical connection parts in the electrical apparatus. Electrical connectors (for example; an outlet or a plug, etc) are devices that connect electric energy and complete electrical circuits. In these connections, the heat is generated by the poor contact according to the slack and the vibration between an outlet receptacle and a plug pins. Excessive heat generation can occur when current, acceptable for the rating of the wire, passes through a poor contact. When overheating due to poor contact occurs, current passes through the increased resistance of a poor connection that is connected in series with the desired load. The heat is generated and the temperature increases, causing degradation of the surrounding combustibles at a focused point or small area. In this paper, it is studied the heating and electrical properties according to the poor contact at PVC insulated plug, and analyzed surface state, surface structure of the grown oxide at the contact part of PVC insulated plug pins. We expect to contribute to prevention of the electrical accident occurring at PVC insulated plug contact part on the basis of this paper.

The purpose of the study was to evaluate the image quality and discriminative ability of FDG-PET images reconstructed by filtered back projection (FBP) and ordered subset expectation maximization (OSEM) in patients with lung cancer. Thirty-six subjects including normal controls and lung cancer patients underwent whole body PET scan (emission 3 min, transmission 1 min) using a GE Advance scanner after the administration of approximately 370 MBq of FDG. The raw data were then reconstructed by conventional FBP and OSEM. The PET images were interpreted by two observers with random exposure of normal and diseased cases for transverse and coronal sections. The results were evaluated using receiver operating characteristic (ROC) curve analysis. The optimal parameters for reconstructing by OSEM involved 2 iterations and 16 subsets. The image quality of thirty-six subjects including normal controls and lung cancer patients reconstructed by OSEM was generally superior to FBP in terms of visual analysis. Though FBP had poor image quality, it had better image contrast than OSEM. The ROC curve plotted for the identification of lung cancer in coronal sections showed better results than in transverse sections by FBP and OSEM, except for the OSEM result of observer 2. ROC analysis showed that OSEM performed better than conventional FBP in terms of its discriminative ability of lung cancer with FDG PET, although there was no significant difference in the area under the ROC curve (p-value >0.05). The results suggest that the simultaneous use of FBP and OSEM images is helpful for the FDG-PET diagnosis of lung cancer.