• Journal of Preventive Medicine and Public Health
• /
• v.26 no.4 s.44
• /
• pp.541-550
• /
• 1993

In order to investigate psychological and behavioral characteristics of homosexuals and to present evidence that homosexuals are in danger of HIV infection in Korea, this study was done by self-administered questionnaire and then direct interview with the 28 (35%) HIV infected homosexual/bisexuals of 79 HIV infected persons reported in 1992. Homosexuals without heterosexual activity were 9 and the others were bisexuals. Sixty-five percent of respondents had a guilty conscience for their homosexual activty. Twenty (71%) were in twenties and 5 (18%) in thirties. Twelve(43%) were detected via health card checking by health office, 21% by blood donation, 18% by hospital visit, and 7% by partner notification. Motivations for homosexual activity were curiosity (36%), temptation or recommendation (14%) and compulsion (11%). Eighteen (72%) never used condom on anal sex. Nine of 26 respondents had experience for anal sex with foreigners. Fourteen (54%) of 26 respondents had history for sexually transmitted diseases. Fighty percent did not have sexual contact after HIV infection and the others usually used condom. It was confirmed that over 57% of the respondents were infected within 1 year before HIV diagnosis and over 82% within 2 years. These data suggest that HTV infection among homosexual group is rapidly spreading.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.50 no.10
• /
• pp.479-488
• /
• 2001

The effects of accelerated Ultraviolet (UV) radiation on High temperature vulcanized (HTV), Room temperature vulcanized (RTV) silicone rubber and two types of ethylene propylene diene terpolymer (EPDM) used for composite insulator were inverstigated by hydrophobicity class (HC), surface voltage decay after corona charging, SEM-EDS, FTIR and XPS. The contact angle in two kinds of silicone rubber was scarcely change, but EPDM occurred to the loss of hydrophobicity followed by surface cracking and chalking. The surface voltage decay on UV-treated silicone rubber and EPDM showed a different decay trend with UV treatment. EDS and XPS analysis indicated that the oxygen content increased with UV treatment time in all samples. For silicone rubber, the oxidized groups of inorganic silica-like structure increased with UV treatment time. The oxidized carbon of C=0, O=C-O in EPDM increased. These oxidized surface for each material had different electrostatic characteristics, so deposited charges were expected to have different impacts on their surface hydrophobicity. The degradation mechanism based on our results was discussed.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.50 no.10
• /
• pp.494-499
• /
• 2001

The effects of accelerated Ultraviolet (UV) radiation on High temperature vulcanized (HTV), Room temperature vulcanized (RTV) silicone rubber and two types of ethylene propylene diene terpolymer (EPDM) used for composite insulator were investigated by hydrophobicity class (HC), surface voltage decay after corona charging, SEM-ES, FTIR and XPS. The contact angle in two kinds of silicone rubber was scarcely change, but EPDM occurred to the loss of hydrophobicity followed by surface cracking and chalking. The surface voltage decay on UV-treated silicone rubber and EPDM showed a different decay trend with UV treatment. EDS and XPS analysis indicated that the oxygen content increased with UV treatment time in all samples. For silicone rubber, the oxidized groups of inorganic silica-like structure increased with UV treatment time. The oxidized carbon of C=O, O=C-O in EPDM increased. These oxidized surface for each material had different electrostatic characteristics, so deposited charges were expected to have different impacts on their surface hydrophobicity. The degradation mechanism based on our results was discussed.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.5
• /
• pp.246-249
• /
• 2017

Pollution flashover of outdoor insulators is a common risk, which affects the safe operation of overhead transmission networks. Early electrical power systems, which feature insulators made from ceramic materials have been used all over the world with good performance. At present, non-ceramic insulators are in common use, as a result of their good electrical as well as mechanical properties. The aim of this paper is to discuss and compare the flashover performance of insulators typically used in power lines, such as, porcelain, ethylene-propylene-diene-monomer (EPDM) rubber, room temperature vulcanized (RTV) and high temperature vulcanized (HTV) coated silicone rubber. The effect of various parameters, including the severity of pollution, ice accumulation, and shade profile, are considered.. From the studies reviewed it was concluded that there is a distinct difference in the flashover voltages of different types of insulators, and the silicone provides the best flashover performance of all insulating materials.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.1025-1028
• /
• 2005

Generally, fiber-reinforced composites have the highest possibilities of impact damages with external object collisions. Also, resulting in fatigue fracture considering the continued impact load. For the reasons mentioned above, the accurate understanding of interactions between the impact of composites and the fatigue load will be essential to understand the safety level of material structures. Furthermore, the composite materials and structures, due to the geometrical effect, vary the life in connection with the impact-fatigue. Therefore, I have reached the point that a focus of this study will be to evaluate fatigue fracture characteristics by the impacts-fatigue load of fiber-reinforced composites. Thus, in this paper, I have tried to work on impacts-fatigue load causing aspects and impact characteristics through impact-fatigue test on HTV-5Hl Black 9250 material made- structure, along with to evaluate the expected lift of real structures, the FEM analysis was carried out.