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고분해능의 방위각 추정을 위한 개선된 MUSIC 알고리듬
윤경식 김천대학교 1996 김천대학교 논문집 Vol.17 No.-
In this paper, the MUSIC algorithm is modified when two targets exist closely. It is shown that the signal subspace eigenvector is represented by a proper combination of the direction mode vectors. The proposed algorithm obtains the null spectrum by using the fact that the signal subspace eigenvectors are orthogonal to the noise subspace eigenvectors. The proposed algorithm estimates the DOA's which minimize the proposed null spectrum. The proposed algorithm has similar resolution capability and reduces the computational burden comparedto that of root-MUSIC.
윤경식,김명녀,김학희 한국공업화학회 2004 응용화학 Vol.8 No.1
Activated carbons were prepared from agricultural wastes by chemical activation with KOH. The seed of water-melon was used as raw materials. Preparation process involves the roasting of raw material and carbonization of roasted material followed by chemical activation. N₂-BET surface areas and total pore volumes of activated water-melon char prepared by chemical activation were measured as 128∼978㎡/g and 0.002∼0.317㎤/g, respectively. Adsorption of methylene blue in solution by activated carbon was carried out and the adsorbate transmittance of methylene blue was determined UV absorption at 660nm using UV spectrophotometer.
윤경식,권태현,박윤수,조강현,김학희 한국공업화학회 2004 응용화학 Vol.8 No.2
Activated carbon was widely used in industrial application such as purification of gas and water, catalyst, or catalyst support and separation process etc., owing to its highly adsorption capacity. In this paper, activated carbon was produced from water-melon seed, which is an agricultural by product, by chemical activation with ZnCl₂, NaOH and KOH. Preparation process involve the roasting of raw material and carbonization of roasted material followed by chemical activation. N₂-BET specific surface areas of activated water-melon char prepared by chemical activation were measured as 128-978 ㎡/g with 100-300 wt% chemical ratio of ZnCl₂, NaOH and KOH, respectively. Removal of phenol in solution by activated carbon was carried out and structure change of pore surface was observed by SEM.
윤경식,김명녀,김경호,김학희 한국공업화학회 2004 응용화학 Vol.8 No.2
Activated carbon was produced from grape-seed, which is an agricultural by-product, by chemical activation with NaOH, KOH and ZnCl₂. It was examined the characteristics of activated carbon through BET specific surface area, N₂ adsorption isotherm, pore size distribution, average pore radius, pore volume and SEM photograph. Especially, most important factor of activated carbon produced by chemical activation was a ratio of chemical agent. The N₂-BET specific surface areas of activated grape-seed char prepared by chemical activation were measured as about 44.09 -121.33 ㎡/g with 100-300 wt% chemical ratio of NaOH, KOH and ZnCl₂, respectively. Removal of chromium in solution by activated carbon was carried out.
포도씨 활성탄에 의한 n-Hexane gas의 기상흡착
윤경식,김환영,김명녀,박윤수,김학희 한국공업화학회 2005 응용화학 Vol.9 No.1
Korean grape-seed that is one of the agricultural wastes was used as a raw material to prepare activated carbon through roasting, carbonization and chemical activation processes. NaOH was used as activation reagent. It was examined the chracteristics of activated carbon through BET specific surface area, pore size distribution, average pore radius, pore volume and SEM photograph. The mixing of the ratio of the grape-seed and activation reagent was varied to 100 ~ 300 weight percent. The surface areas of the activated carbon manufactured from the grape-seed were 47.9- 121.3 ㎡/g. Adsorption of n-Hexane gas by our activated carbon under gas phase was carried out and structural change of pore surface was observed by SEM.