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Reinforcement of Rubber Properties by Carbon Black and Silica Fillers: A Review
( Gon Seo ),( Do-il Kim ),( Sun Jung Kim ),( Changseok Ryu ),( Jae-kyoung Yang ),( Yong-gu Kang ) 한국고무학회 2017 엘라스토머 및 콤포지트 Vol.52 No.2
Enhancing the properties of rubber, such as the tensile strength, modulus, and wear abrasion, by the addition of carbon black and silica as fillers is very important for improving the performance of rubber products. In this review, we summarize the general features of `the reinforcement of rubber by fillers` and the equations for representing the reinforcement phenomena. The rubber reinforcement was attributed to enhancement of the following: the rubber, bound rubber, formation of networks, and combination between rubber chains and silica followed by entanglement. The reinforcement capability of silica species with different surface and networked states demonstrated the importance of the connection between the silica particles and the rubber chains in achieving high reinforcement. The model involving combination followed by entanglement can provide a plausible explanation of the reinforcement of rubber by carbon black and silica because the combination facilitates the concentration of rubber chains near the filler particles, and entanglement of the rubber chains around the filler particles enforces the resistance against deformation and breakage of rubber compounds, resulting in high reinforcement.
Seo, Gon,Kim, Tae Jin,Lim, Sam Kook,Ko, Chang Hyun,Ryoo, Ryong 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.6
Catalytic reduction of dissolved oxygen by hydrazine at room temperature was investigated on Pt catalysts supported on KIT-1 mesoporous material and Y and ZSM-5 zeolites. Pt catalyst supported on AlHIT-1 mesoporous material exhibited high performance ascribed to the high dispersion of Pt and the large diameter lowering diffusion restriction.
THE RATE OF NUCLEI FORMATION OF ZSM -5 ZEOLITE
Seo, Gon,Chung, Kyeong Hwan,Kim, Keun Shik 한국화학공학회 1992 Korean Journal of Chemical Engineering Vol.9 No.3
The crystallization processes of ZSM-5 zeolite from mixture of colloid silica, sodium aluminate, sodium hydroxide and tetrapropyl ammonium bromide at 150-195℃ were studied. As the temperature increases, crystallization time decreases, crystal size becomes smaller, and the distribution becomes narrower. The rate of nuclei formation is deduced from the size distribution of final product under the assumption that crystal is growing at constant rate from the nuclei formed during the induction period. The rate of nuclei formation is also accelerated with temperature increase. When the rate constants of the crystal growth axe 0.012-0.170 ㎛·min^(-1) at 150-195℃, the crystallization curves can be simulated with the rate equation of nuclei formation deduced from the crystal size distribution of the final product.
Skin barrier repair for the prevention of radiation dermatitis in head and neck cancer patients
( Seo Mi Gon Jeong ),( Chang Il Kwon ),( Young Bin Shin ),( Yun Sun Moon ),( Eui Chang Jung ),( Chi Yeon Kim ),( Tae Jin Yoon ) 대한피부과학회 2020 대한피부과학회 학술발표대회집 Vol.72 No.1
Background: To date, the clinical benefit of topical steroid use has only been demonstrated for radiation dermatitis induced by 50-60Gy in breast cancer. Radiation dermatitis is characterized by erythema, itching, pain, and burning sensation, and there is no consensus on how to prevent it. Objectives: In this study, we clarify the additional benefit of topical steroid and preventive emollient care for radiation dermatitis induced by high-dose (>60Gy) irradiation with chemotherapy in advanced squamous cell carcinoma of the head and neck (SCHN) patients. Methods: Patients with definitive chemoradiotherapy (CRT), when radiation dermatitis grade 1 is seen or total radiation dose reaches 30Gy. If radiation dermatitis worsens to grade 2, the irradiated area will be covered with a moderately absorbent surgical pad only or steroid and topical cream with it. Results: The median radiation dose before the development of grade 2 skin toxicity was <60.5Gy in patients with SCHN. Almost of patients (85.7%) complained burning and local erosion during planned CRT. Standard care was initiated on 78.5% of patients during the study (surgical pad: 78.5%, steroid only:14.4%, emollient only:21.4% both:50.0%). The most effective prescribed modalities in all arms were steroid with emollient in surgical pad covering. Conclusion: This study shows that the clinical benefit of topical steroid and emollient for radiation dermatitis induced by high-dose irradiation with chemotherapy.
Shape - Selective Alkylation of Isopropylnaphthalene on MCM-22 Zeolite
Seo, Gon,Kim, Jong Ho,Kim, Myung Wan,Sugi, Yoshihiro 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.4
An MCM-22 zeolite with an Si/Al ratio 13 was found to exhibit higher selectivity to β,β-diisopropylnaphthalene in the alkylation of isopropylnaphthalene with isopropylalcohol, as compared with other zeolites such as mordenite, Y and beta having similar Si/Al ratios. This high selectivity is ascribed to the specific pore shape of MCM-22 zeolite. The gradual increase in the selectivity with reaction time is due to its pore modification by coke deposit.