http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 서정권 (검색결과 212 건)
- 무료
- 기관 내 무료
- 유료
-
서정권,최영엽 한국섬유공학회 1996 한국섬유공학회지 Vol.33 No.1
The Penetration force and energy Per cycle developed during needle Penetration into and withdrawal from a fabric were measured on a sewing machine attached penetration force detector. Five major variables considered were sewing speed, needle diameter, needle point shape, needle surface finish, and number of fabric plies. It was found that the sewing speed had little effect on the penetration energy in the range of actual sewing speed. The needle diameter significantly affected the penetration energy, but the needle size did not affect the heat of the needle. The heat rises as the needle diameter increases, however, the increase of the heat dissipation due to the heat conduction and heat convection did not show much difference in the needle temperature. The usage of medium ballpoint needle was effective in reducing the penetration energy according to the type of fabric and especially the usage of super needle distinctly lowered the penetration energy. As expected, the number of fabric plies were the most important factors influencing the penetration energy.
-
-
Zeolite 결정 성장에 미치는 Hydrogel화의 영향
서정권,이광석,이정민,정필조 한국세라믹학회 1989 한국세라믹학회지 Vol.26 No.4
The effects of raw material feeding procedures and gelation temperatures on zeolite synthesis are investigated. Thus, the synthesis of zeolite 4A from sodium aluminate and sodium silicate solutions is chosen as a model reaction, for which equi-molar hydrogelation is performed with variation of feeding procedures and gelation temperatures. The formation of crystal nuclei, often being referred to as precursors, is induced under different conditions, the variation being examined by means of viscosity and water contents. The final products of zeolite 4A are evaluated by XRD, SEM morphology, particle size analysis and cation exchange capacity. Evidence shows that the viscosity of the initial products and their water contents are markedly influenced by the feeding methods of the reactant materials and by the gelation temperature. Further, it is found that the gelation at an elevated temperatures near 7$0^{\circ}C$ can be made possible through modification of mixing procedures. This provides convenient means of controlling the particle size of the final products. In this regard, a continuous flow-type mixing technique is proposed, which is demonstrated to be superior to the conventional batch-type mixings. The significance of this finding may lie in savings of equipment as well as energy costs, especialy on a large scale commercialization of zeolite production.
-
크롬 및 구리가 담지된 La2O3 / Al2O3 계 복합산화물 촉매의 구조 및 열안정성
서정권,하백현 ( Jeong Kwon Suh,Baik Hyon Ha ) 한국화학공학회 1994 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.32 No.6
The structure and thermal properties of Cr and Cu added La₂O₃/Al₂O₃ system were investigated using XRD, BET, ESCA, TEM and DTA. During calcination the addition of chromium retarded the phase transition of La-β-Al₂O₃ and improved the thermal stability of La₂O₃/Al₂O₃ system at highly temperature. However the addition of copper on La₂O₃/Al₂O₃ system accelerated the phase transition of support. The surface area after being calcined at 1,200℃ for 2 hours was 40 ㎡/g for (Cr₂O₃) (La₂O₃) (Al₂O₃)_(19) oxide and 10 ㎡/g for (CuO)(La₂O₃)(Al₂O₃)_(19) oxide. The sintering of La₂O₃/Al₂O₃ system at 1,000℃ proceeded via surface diffusion and was not influenced by the Cr addition. The sintering of Cu added La₂O₃/Al₂O₃ system proceeded via viscous flow. The activation energy of the phase transition above 1,200℃ had a constant value about 600 kJ/㏖, regardless of the Cr and Cu addition.
-
-
-
전이 금속 산화물이 담지된 La / Al 복합산화물 촉매상에서의 메탄 연소반응
서정권,하백현,고재천,이정민 ( Jeong Kwon Suh,Baik Hyon Ha,Jae Cheon Koh,Jung Min Lee ) 한국화학공학회 1993 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.31 No.6
Combustion catalysts were prepared by the impregnation of transition metal oxide on La/Al oxide(Al₂O₃/La₂O₃=19), and then calcined in air. Methane combustion was carried out using these catalysts. X-ray diffraction analysis indicates that La/Al oxide was crystallized from amorphous form into La-β-Al₂O₃ phase above 1200℃. Crystallization was accelerated by the addition of copper on La/Al oxide, but it was retarded by the addition of chromium on La/Al oxide. The copper content of the surface of CuO-La/Al oxide decreased as the calcination temperature increased. This result indicates the formation of solid solution. In case of Cr₂O₃-La/Al oxide, Cr₂O₃mainly existed on the catalyst surface. The activities of catalysts calcined at 1200℃ appeared as the following order; CuO, Cr₂O₃>Fe₂O₃>MnO>CoO>NiO. The catalytic activity of CuO-La/Al oxide decreased as the calcination temperature increased. However the catalytic activity of Cr₂O₃-La/Al oxide was still maintained after calcination at 1400℃.
-
-
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
