• Tribology and Lubricants
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• 제21권6호
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• pp.272-277
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• 2005

Continuously variable transmission (CVT) of toroidal type has a elliptical shape of contact zone under the elastohydrodynamic lubrication (EHL) condition, where the power is transmitted only by shearing the lubricant. Due to the small contact area of elliptical shape, the traction of the shear behaviors of lubricant over the contact zone is under extremely high contact pressure over 1.0GPa. During the power transmission by shearing the fluid, many kinds of mechanical movements occur such as squeezing, sliding, rolling and spin. Among the movements, the spin effect that is the most undesirable contact behavior in transmitting the power frequently makes significant abnormal wear damage. In this work, the analysis of elliptical contact of EHL with spin effect is performed, which will give very useful information to understand the traction behaviors in toroidal type of CVT system.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제4권11호
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• pp.479-486
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• 2015

모델 체킹 방법은 가능한 모든 경우를 자동으로 확인할 수 있으며, 코드가 구현되기 이전의 명세서나 디자인의 검증에도 적용할 수 있어 고위험 시스템의 검증에 활발히 적용되어왔다. 그러나 이러한 엄밀한 검증기법에 대한 일반적인 이해 부족과 테스팅에 비해 높은 검증 비용으로 인하여, 일반적인 소프트웨어들은 여전히 인력에 의한 테스팅과 같은 기초적인 방법에 의존하여 검증이 수행되고 있다. 본 논문에서는 그 대표적인 예인 온라인 게임 서버를 대상으로, SPIN 모델 체커(SPIN model checker)를 이용한 자동화 검증 방법을 적용하는 실험적인 연구를 수행하여 검증 비용 대비 효과에 근거한 적용성을 판단하였다. 연구 결과, 5~7GB 이내의 메모리와 10분 이내의 시간 내에서 온라인 게임 서버 파티 시스템의 주요 특성들을 검증할 수 있음을 보였고, 이 과정에서 기존에 파악하지 못한 오류도 검출하였다. 이로부터 인력에 의한 테스팅에 비해 납득할만한 수준의 검증 비용으로 엄밀하고 효과적인 검증이 가능하다는 결론을 도출할 수 있었다.

• Environmental Engineering Research
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• 제24권4호
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• pp.646-653
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• 2019

Recovery of valuable metals in the industrial wastewater and sludge has attracted an attention owing to limited metallic resources in the earth. In this study, we firstly fabricated Ti/Ir-Ru electrodes by spin coating technique for effective recovery of Cu in electrowinning process. Two different Ti/Ir-Ru electrodes were fabricated using 100 and 500 mM of precursors (i.e., Ir-Ru). SEM-EDX and AFM revealed that Ir and Ru were homogenously distributed on the surface of Ti plate by the spin coating, in particular the electrode prepared by 500 mM showed distinct boundary line between Ir-Ru layer and Ti substrate. XRD, XPS, and cyclic voltammetry also revealed that characteristics of IrO₂, RuO₂, and TiO₂ and its electrocatalytic property increased as the concentration of coating precursor increased. Finally, we carried out Cu recovery experiments using two Ti/Ir-Ru as anodes in electrowinning process, showing that both anodes showed a complete removal of Cu (1 and 10 g/L) within 6 h reaction, but much higher kinetic rate constant was obtained by the anode prepared by 500 mM. The findings in this study can provide a fundamental knowledge for surface characteristics of Ti/Ir-Ru electrode prepared by spin coating method and its potential feasibility for effective electrowinning process.

• 한국기계가공학회지
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• 제10권6호
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• pp.146-151
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• 2011

Wax spin coating is a part of several wafer handling processes in the silicon wafer polishing station. It is important to ensure the wax layer free of contamination to achieve the high degree of planarization on wafers after wafer polishing. Three-dimensional air flow characteristics in a wax spin coater are numerically investigated using computational fluid dynamics techniques. When the bottom of the wax spin coater is closed, there exists a significant recirculation zone over the rotating ceramic block. This recirculation zone can be the source of wax layer contamination at any rotational speed and should be avoided to maintain high wafer polishing quality. Thus, four air suction ducts are installed at the bottom of the wax spin coater in order to control the air flow pattern over the ceramic block. Present computational results show that the air suction from the bottom is quite an effective method to remove or minimize the recirculation zone over the ceramic block and the wax coating layer.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.325-329
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• 2002

In this study, the dependency of the behavior of propagating front on the reaction condition in frontal polymerization reaction has been studied. We have used some multifunctional acrylates as a monomer and ammonium persulfate as an initiator for the polymerization reactions. In frontal polymerization, a method of producing polymeric materials via a thermal front that propagates through the unreacted monomer/initiator solution, the behavior of self propagating front shows various dynamic patterns depending on the reaction condition. We have obtained some spin modes of propagating front in the number of 'hot spots' or 'spin heads' by changing the reaction condition. The effect of the reactor tube diameter on the mode of propagating front has also been studied by using some reactor tubes with different size of tube diameter and it has been examined in some detail by adopting an experimental method of two-tubes system.

• 대한기계학회논문집
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• 제19권1호
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• pp.1-13
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• 1995

In order to investigate the effect of liquid balancer in washing machine, we identify the vibration characteristics of suspension system of washing machine and formulate the 4 D. O. F. system dynamic equations. As the washing machine rotates higher speed, it is emphasized to reduce the ecentric force due to unbalanced mass. Nowadays, the most effective cancelling method of eccentric force is known as the usage of liquid balancer. To determine the liquid distribution in liquid balancer, the fluid statics is considered. The system dynamic equations are solved by Runge-Kutta method and represent the good characteristics of real washing machine in X-Y plane. The accuracy of the numerical solution was examined by experiments. The simulation results show that the unbalanced mass has so much influence on vibration magnitude and the rotating shape of spin-basket. But the effect of mass reduction due to the dehydration of the spin-basket has little influence on transient vibration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1885-1890
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• 2004

In this paper the numerical method with a zonal embedded grid system was applied to the spin-up flow within a semi-circular container. Flow visualization was also performed on a rotating table. The results show that at a low level of damping (i.e. low viscosity and high liquid depth) a cyclonic cell produced initially near the left-hand-side corner of the container moves along a wall and merged with the cell on the right-hand-side.

• 전기전자학회논문지
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• 제27권1호
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• pp.78-84
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• 2023

본 논문에서는 컬러 용액을 사용하여 스핀 코팅 방식으로 Building Integrated Photovoltaic(BIPV) 시스템용 전면 컬러 유리를 구현하였다. 컬러 유리 구현을 위해 진주광택 안료와 다양한 용액를 사용하여 컬러 용액에 적합한 용액을 조사하였다. 조사한 용액 중 자외선 광 경화제인 NOA series의 경우 다른 용액보다 우수한 코팅성과 컬러 재현성을 가진 컬러 유리를 구현할 수 있었다. NOA 65 기반의 컬러 용액으로 스핀 코팅하여 구현한 컬러 유리는 가시광선 및 근적외선 파장 대역에서 최대 86%의 높은 투과율을 보였으며 시간에 따른 컬러 유리의 광학적 특성의 변화가 미미하여 BIPV용 컬러 유리 구현을 위한 컬러 용액으로 적합하였다. 스핀 코팅 방식을 활용한 용액 공정 방식은 기존의 물리적 증착 방식이나 나노 입자를 활용한 컬러 유리 제작 공정보다 쉽고 빠르게 컬러 유리를 제작할 수 있어 BIPV용 전면 컬러 유리 제작 공정이 용이해질 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1724-1728
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• 2002

The adsorption of proteins on the surface of glass slides is essential for the construction of protein chips. Here, we report that a Histidine (His)-tagged protein protein has been efficiently adsorbed on glass coated with nickel. A variety of nickel chloride-coated plates were prepared by the spin-coating method and adsorbed to the His-tagged protein. When the protein was adsorbed onto the surface of a variety of nickel chloride-coated glass slides, the efficiency of protein adsorption was dependent upon the coating conditions such as nickel chloride concentration, the spin speed and the drying temperature. The slides appropriate for protein adsorption were obtained when the slides were coated with 11%(w/w) of $NiCl_2$ at the spin speed of 4000 rpm for 20 sec and then dried at higher than 40°C. The physical properties of their nickel chloride thin layer were characterized by scanning electron microscopy. x-ray diffraction and atomic force microscopy, finding that the nickel chloride particles were around 10 nm in diameter and uniformly crystallized at 101 faces. These results show that nickel chloride-coated slides prepared by the spin-coating method are utilizable for the construction of Histagged protein chips.

• Tribology and Lubricants
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• 제23권2호
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• pp.49-55
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• 2007

A numerical analysis of elastohydrodynamic lubrication of elliptical contacts with both rolling and spinning has been carried out. A finite difference method with non-uniform grid systems and the Newton-Raphson method are applied to solve the problems. The velocity vectors resulting from combined spinning and rolling/sliding motion lead to asymmetric pressure distributions and film shapes. Pressure distributions, film contours and variations of the minimum and central film thicknesses are compared with various spin-roll ratios. Reduction of the minimum film thickness under spinning is remarkable whereas the central film thickness is relatively less. The spin motion have large effect on variations of the minimum film thickness with load parameter which are small in pure rolling/sliding cases. Therefore present numerical scheme can be used in the analysis of general elliptical contact EHL problems and further studies are required.