• 대한수학회지
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• 제43권3호
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• pp.659-676
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• 2006

In this paper, we consider three-component reaction-diffusion system. With an integral condition and a global coupling, this system gives us an interesting free boundary problem. We shall examine the occurrence of a Hopf bifurcation and the stability of solutions as the global coupling constant varies. The main result is that a Hopf bifurcation occurs for global coupling and this motion is transferred to the stable motion for strong global coupling.

• Bulletin of the Korean Chemical Society
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• 제16권9호
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• pp.859-863
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• 1995

The prostaglandin analogue 12-epi-PGF2α (2) has been synthesized from optically active cis-4-t-butyldimethylsilyloxy-2-cyclopenten-1-ol (4b) in 4 steps in an overall yield of 21%. An extremely efficient Pd(Ⅱ)-mediated, three-component coupling reaction is employed to obtain the key intermediate 9.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.112-118
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• 2002

Good-to-excellent yields of 2,3-Disubstituted norbornenes (or norbornanes) were obtained using a Pd/Cu catalyzed three-component ternary coupling reaction of aryl halides, norbornadiene (or norbornene), and alkynols in toluene at $100{\circ}C$ in the presence of 5.5 M NaOH as a base and benzyltriethylammonium chloride as a phase transfer catalyst. The results of experiments using various aromatic halides suggest that the ternary coupling reaction is promoted by bromide.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.179-187
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• 2013

We describe newly developed software named KPACK for relativistic electronic structure computation of molecules containing heavy elements that enables the two-component ab initio calculations in Kramers restricted and unrestricted formalisms in the framework of the relativistic effective core potential (RECP). The spin-orbit coupling as relativistic effect enters into the calculation at the Hartree-Fock (HF) stage and hence, is treated in a variational manner to generate two-component molecular spinors as one-electron wavefunctions for use in the correlated methods. As correlated methods, KPACK currently provides the two-component second-order M${\o}$ller-Plesset perturbation theory (MP2), configuration interaction (CI) and complete-active-space self-consistent field (CASSCF) methods. Test calculations were performed for the ground states of group-14 elements, for which the spin-orbit coupling greatly influences the determination of term symbols. A categorization of three procedures is suggested for the two-component methods on the basis of spin-orbit coupling manifested in the HF level.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.837-841
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• 2001

The column-type sensing element in building and mechanical construction parts was designed as three forces and three moments sensor by attaching strain gages approximately. Compared to conventional multi-component sensor, the designed sensor can solve the problem about low stiffness and high cost. The radius of the column was designed analytically and compared with finite element analysis. The coupling errors between components were minimized by using addition and subtraction procedure of signals. The fabricated sensor was tested by using a deadweight force standard machine and a six-component force calibration machine in Korea Research Institute of Standards and Science(KRISS). The calibration showed that the multi-component force/moment sensor had coupling error less than 19.8 % between $F_x$ and $M_y$ components, and 9.0 % in case of other components.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1556-1560
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• 2012

A simple highly versatile and efficient method has been developed for the three-component coupling of aldehydes, amines and alkynes to prepare propargylamines, in the presence of a catalytic amount of $BiCl_3$. The advantages of methods are high yield, mild reaction conditions, no environmental pollution and easy work up procedure.

• 한국컴퓨터산업학회논문지
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• 제4권4호
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• pp.479-490
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• 2003

컴포넌트 기반 소프트웨어개발 (CBD: Component Based Development)은 재사용 부품을 기반하여 소프트웨어 개발, 수정, 유지보수를 용이하게 지원한다. 따라서 컴포넌트는 강한 응집력과 양한 결합력으로 개발되어야 한다. 본 논문에서는use case와 클래스를 간에 유사성을 통한 클러스터링 분석에 기반 하여 컴포넌트 식별에 대해 연구한다. 컴포넌트 참조 모델과 프레임워크를 제시하여 사례를 통해 검증한다. 컴포넌트 식별 방법은 추출, 명세 및 아키？쳐를 지원한다. 이들 방법론은 기존의 객체지향 방법론을 참조하며 분석에서 구현까지의 추적성을 지원하며 재사용 컴포넌트의 모듈성 지원을 위해 강한 응집력과 약한 결합력을 반영한다.

• 한국정밀공학회지
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• 제17권5호
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• pp.100-107
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• 2000

The hydraulic couplings have been widely used in industries, automobile, and power-station drives including ships. A mathematical analysis by which the design and application of hydraulic couplings are made is used in conventional design formulae and general roto-dynamic theories. The fluid flow of hydraulic couplings can be considered to have two component, one circumferentially about the coupling axis, and the other passing fluid from the pump to the turbine in the plane of the coupling axis. Tests have been carried out on the full-scale production coupling. The performance test consists of taking measurement of torque of the fluid coupling for three different amount of working fluid inside with various loads to the output shaft. The purpose of this research is to construct the experimental test equipments and to establish a series of performance test for the domestically developed hydraulic couplings, and to obtain experimental results which can be used to improve the performance of the hydraulic coupling and to solve the practical problems confronted in operation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.244-245
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• 2013

This paper proposes a control algorithm for permanent magnet synchronous generator with a back-to-back three-level neutral-point clamped voltage source converter in a medium-voltage offshore wind power system under unbalanced grid conditions. The proposed control algorithm particularly compensates for the unbalanced grid voltage at the point of common coupling in a collector bus of offshore wind power system. This control algorithm has been formulated based on the symmetrical components in positive and negative rotating synchronous reference frames under generalized unbalanced operating conditions. Instantaneous active and reactive power are described in terms of symmetrical components of measured grid input voltages and currents. Negative sequential component of ac input current is injected to the point of common coupling in the proposed control strategy. The amplitude of negative sequential component is calculated to minimize the negative sequential component of grid voltage under the limitation of current capability in a voltage source converter. The proposed control algorithm makes it possible to provide a balanced voltage at the point of common coupling resulting in the generated power of high quality from offshore wind power system under unbalanced network conditions.

• 한국전산유체공학회지
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• 제16권2호
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• pp.30-48
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• 2011

A three-dimensional thermal-hydraulic code, CUPID, has been developed for the analysis of transient two-phase flows at component scale. The CUPID code adopts a two-fluid three-field model for two-phase flows. A semi-implicit two-step numerical method was developed to obtain numerical solutions on unstructured grids. This paper presents an overview of the CUPID code development and assessment strategy. The governing equations, physical models, numerical methods and their improvements, and the systematic verification and validation processes are discussed. The code couplings with a system code, MARS, and, a three-dimensional reactor kinetics code, MASTER, are also presented.