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판재의 드로우비드 성형시 비드표면처리와 비드형상이 인출 및 마찰특성에 미치는 효과
이동활 ( Dong Hwal Lee ),류종수 ( Jong Soo Ryu ),정우창 ( Woo Chang Chung ),문영훈 ( Young Hoon Moon ) 한국열처리공학회 2005 熱處理工學會誌 Vol.18 No.2
N/A In sheet metal forming, drawbeads are often used to control uneven material flow, which may cause defects such as wrinkles, fractures, surface distortion and springback. Appropriate setting and adjusting of the drawbead force is one of the most important parameters in sheet forming process control. Therefore in this study, drawbead test was performed at various bead surface treatment conditions to clarify the frictional characteristics between sheet and drawbead. Furthermore, the differences in drawing force between circular and rectangular shape beads have also been measured to estimate the effectiveness of bead shape on the material flow control. The results show that drawing and friction characteristic were strongly influenced by surface treatments of bead and bead shapes.
하동 Kaolin 으로 부터의 Zeolite 합성 반응 속도
정우창,김면섭,권이열 한국화학공학회 1977 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.15 No.2
우리나라산 하동 kaolin (halloysite)을 과량의 1N수산나트륨수용액으로 60℃, 80℃ 및 100℃에서 1∼50시간 처리하여 생성된 무정형 aluminosilicate, sodium A zeolite, hydroxysodalite를 halloysite→^k₁무정형 aluminosilicate→^k₂ sodium A zeolite→^k₃ hydroxysodalite 의 반응기구에 적용시켜 각각의 반응속도 정수를 구하였다. 또한 halloysite로 부터 무정형 aluminosilicate로 되는 반응의 activation energy는 10㎉/㏖이고 무정형 aluminosilicate로 부터 sodium A zeolite로 되는 경우는 16㎉/㏖이며 sodium A zeolite로부터 hydroxysodalite로 되는 경우는 7㎉/㏖임을 알았다. Amorphous aluminosilicate, sodium A zolite and hydroxysodalite were obtained by treating Hadong-kaolin (halloysite) with 1N aqueous sodium hydroxide solution for one to five hours and with temperature range from 60 to 100℃. The reaction mechanism was observed as first order consecutive reaction as follows : halloysite→^k₁ amorphous aluminosilicate→^k₂ sodium A zeolite→^k₃ hydroxysodalite By applying the above reaction mechanism, rate constants and activation energies were measured. The activation energies of the reactions from halloysite to amorphous aluminosilicate, from amorphous aluminosilicate to sodium A zeolite, and from sodium A zeolite to hydroxysodalite were 10㎉/㏖, 16㎉/㏖, and 7㎉/㏖, respectively.
정우창,남궁식,문세기 한국화학공학회 1967 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.5 No.2
An alternative measurement of gas cross flow coefficient between the bubble phase and emulsion phase, and the density of the solid particles in the bubble of a gas-solild, two demensional fluidized bed are proposed, using the tracer technique and leak-current method. In the range of u_o/u_(mf) from 1.5 to 7.0, the gas cross flow coefficient(K_(bd)) ̄_b and density ratio r_b are decreased rapidly and exponentially, respectively, with the incrase of u_o/u_(mf). It was found that there was a linearlity between (K_(bd)) ̄_b and (K_(bd)) ̄_b and that this proposed (K_(bd)) ̄_b was one of the catalytic fluidized bed design factor for the gas catalytic reaction.