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ZSM - 5 촉매상에서 메탄올로부터 저급올레핀 생성에 관한 연구
정종헌,이준원,이현구 ( Jong Hun Jeong,Jun Won Lee,Hyun Ku Rhee ) 한국화학공학회 1993 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.31 No.3
From the experimental results of methanol conversion over HZSM-5 catalyst, it was observed that around 250℃ methanol was only dehydrated to DME(dimethylether) and the aromatization was promoted by the autocatalytic reaction of light olefins around 310℃. When water was added to the reaction mixture, the selectivities to light olefins and aromatics were found to increase and the degree of deactivation to decrease due to the steam distillative effect exerted by water present in the pore. In case of HZSM-5 catalysts modified by metal impregnation, it was noticed that the Bronsted acid sites decreased because of the partial ion-exchange of H^+ ions by metal ions and that redistribution of acid sites occurred since metal ions and metal-oxides gave rise to an increase in the Lewis acid sites. Also, it is evident that the crystalline metal oxide formed on the catalyst surface during the course of calcination played the role of pore-plugging. For these reasons, the metal impregnated HZSM-5 catalysts showed lower activity and lower rate of deactivation in comparison to the HZSM-5. In particular, the modified catalysts gave substantially higher selectivities to light olefins at the level of 100% conversion of methanol.
알레르기접촉피부염 환자에서 첩포검사 결과의 분석 - 동일기관에서의 10년 전 결과와의 비교
정종헌 ( Jong Heon Jeong ),홍종수 ( Jong Soo Hong ),이승호 ( Seung Ho Lee ),이애영 ( Ai-young Lee ) 대한피부과학회 2020 대한피부과학회지 Vol.58 No.4
Background: Causative antigens in allergic contact dermatitis (ACD) can be changed by several variables, including time and place. Change in antigens over a period of time in the same institution is one way to reduce the variables; however, these investigations have rarely been performed in Korea. Objective: To investigate the change in patch test results by comparing with the results obtained 10 years ago at the same hospital. Methods: Patch test results were analyzed retrospectively through the medical records of patients with suspected ACD who underwent the patch test using Korean standard series between September 2015 and September 2018. The institutional Review Board of the Dongguk University I1san Hospital approved this study. The results of the patch test were compared with those obtained 10 years ago. Results: A total of 360 patients (males: 142, females: 218) were included. Compared with the results obtained 10 years ago, the positivity rates of metal-related allergens (nickel sulfate, cobalt chloride, and potassium dichromate), fragrance allergens, and 4-phenylenediamine base were increased, whereas the positivity rates of mercury ammonium chloride, thimerosal, and formaldehyde were decreased. Conclusion: The patch test results obtained at the same hospital over a 10-year interval suggest that causative allergens in ACD could change with time lapse. In the future, collaborative studies including a number of participating hospitals are needed for obtaining more reliable results. (Korean J Dermatol 2020;58(4):254∼259)
정종헌 ( Jong Heon Jeong ),이지영 ( Ji Young Lee ),이승호 ( Seung Ho Lee ),이애영 ( Ai-young Lee ),홍종수 ( Jong Soo Hong ) 대한피부과학회 2020 大韓皮膚科學會誌 Vol.58 No.10
Rhus is a common cause of allergic contact dermatitis (ACD), particularly in East Asia. Rhus can cause localized contact dermatitis following direct contact with the skin, and systemic contact dermatitis following its ingestion, causing pruritus, erythema, and occasionally blistering. Bullous pemphigoid (BP) is an acquired subepidermal autoimmune bullous disease that typically occurs in the elderly. Although BP usually occurs sporadically, some precipitating factors of BP have been suggested, such as other autoimmune diseases, drugs, and malignancies. We report a rare case of BP induced by ingestion of Rhus in a 54-year-old man who presented with itchy erythematous rash and blisters on the whole body, initially misdiagnosed as ACD, and treated with systemic steroids. (Korean J Dermatol 2020;58(10):691∼693)
정관성,이동규,정종헌,이근우,Jeong, Kwan-Seong,Lee, Dong-Gyu,Jung, Chong-Hun,Lee, Kune-Woo 한국방사성폐기물학회 2006 방사성폐기물학회지 Vol.4 No.4
The estimated decommissioning cost of nuclear research reactor is calculated by applying a unit cost factor-based engineering cost calculation method on which classification of decommissioning works fitted with the features and specifications of decommissioning objects and establishment of composition factors are based. Decommissioning cost of nuclear research reactor is composed of labor cost, equipment and materials cost. Labor cost of decommissioning costs in decommissioning works are calculated on the basis of working time consumed in decommissioning objects. In this paper, the unit cost factors and work difficulty factors which are needed to calculate the labor cost in estimating decommissioning cost of nuclear research reactor are derived and figured out.