• Journal of the Society of Naval Architects of Korea
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• v.36 no.1
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• pp.15-21
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• 1999

In this paper, the issue of local structural identifiability of linear equations of motion with non-linear parametrizations is discussed. The test method is resented that provides analytical expressions for information matrices of which the rack determines identifiability. And this method is applied to investigate local structural identifiability of linear equations of motion for a submergible vehicle. As a result, it is showed that with given parameters, the linear equations of motion do not satisfy the definition of local identifiabiliy according Glover & Willems.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.65-66
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• 2006

[ $TiO_2$ ] single crystalline nanorods are prepared from electrospun fibers which are composed of nanofibrils with an island-in-a-sea morphology. The mechanical pressure produces each fibril into nanorods which are converted to anatase single crystals after calcinations. HRTEM shows that the (001) plane is growing along the longitudinal direction of the rod. In this work, the nanorod electrode provides the efficient photocurrent generation in a quasi-solid state dye-sensitized solar cells (DSSCs) using highly viscous PVDF-HFP based gel electrolytes. The overall converision efficiency of the $TiO_2$ nanorods shows 6.2 % under $100\;mW/cm^2$ (AM 1.5G) illumination.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.12
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• pp.1022-1032
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• 1989

King Sejong's Striking Clepsydra was an elaborate timekeeping and annunciating system incorporating biological automata capable of annunciating hours, intervals and night-watches based on Shou-shih calindrical systems automatically. In this paper the author has studied the original manuscripts on the Striking Clepsydra [Sejong sillock, 65: 1a-3b ff` 16th year, 7th month(1434)] from the technical point of view undertaking a close analysis of this monumental clock and aiming to our modern understanding of the full degree of delicate mechanisms and sophisticated controls built into the night-watch and division announcing clockwork(jackwork). Based on the input/output model, timekeeping, ball-rack, ball-relay, and audible time-indicating mechanisms were synthesized reconstructing night-watch annunciating systems. It revealed that the night-watch and division announcing processes were entirely renewed automatically. Historical and philological data concerning the improvements of the proposed model were discussed.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.7-17
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• 1992

The acid stronger than $H_0=-11.93$, which corresponds to the acid strength of 100% $H_2SO_4$, is known as superacid. However, solid superacid catalysts have many advantages such as an easy separation of products from catalyst, the repeated uses and regeneration of catalysts, as compared with liquid superacids. In this paper, the kinds of solid superacids, the preparation methods, and their applications for chemical reactions are introduced.

• Korean Journal of Pharmacognosy
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• v.21 no.3
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• pp.205-209
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• 1990

The study for the quantitative analysis of saikosaponin of Bupleurum falcatum root produced by tissue culture was attempted. The optimal concentration of 2,4-D was 0.1 mg/l for inducing the callus. The induction and growth of the adventitious root from the callus was obtained in the suspension culture containing MS basal medium supplemented with no plant growth regulators. The results of the quantitative analysis of saikosaponins by high performance liquid chromatography (HPLC) showed that the content of saikosaponin a and c was high in the one-year-old root from somatic embryos and that of saikosaponin d was remarkably high in three-months-old adventitious root from callus.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.635-641
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• 1994

Recently, Improving the energy efficiency of a pneumatic system and reducing the consumption of compressed air were a concern of scholars at domestic and abroad. The using fields of a pneumatic system are widely used in factory automation of manufacturing line, chemical factories with explosiveness danger and petroleum industries etc. In particular, Pneumatic cylinder is applied to feeding work of workpiece, jig tools and press mechanism, reciprocation and rotary motion with rack and pinion. In this study, The experimental apparatus consisted to pneumatic cylinder, dual supply pressure regulator and solenoid valve. The dual supply pressure regulator connected to outlet port of solenoid valve. The supply pressure (4.5kgf/cm$\^$2/) of compressed air goes into the rodless chamber 1 to drive the pistion rod forward which is named working stage. The supply pressure(2kgf/cm$\^$2/) of compressed air goes into the rod chamber 2 to drive the piston rod backward which is named no-working stage. Accordingly, The research results of this study can be obtained to Energy-Saving Effects of the compressed air about 35%.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.109-118
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of field test results and simulation results of the ADAMS/Car demonstrates the validity of the proposed functional suspension modeling method. This model is suitable for real-time vehicle dynamics analysis.

• Journal of the Semiconductor & Display Technology
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• v.7 no.4
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• pp.23-28
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• 2008

A high speed automated pitch variation unit (HAPU) related to semiconductor category sorting movement of the test handler system was developed. In the design process, 'DMADOV' step of 6-Sigma method has been applied. The design result for the desirable pitch variation was a 3:1 reduction rack-pinion and a linkage which are operated by servomotors. The realization and reliability of the mechanism was obtained at the design stage by FEM analysis, and by robust design using Taguchi orthogonal array against weight and deformation. Finally, the validity of the high speed variation mechanism was confirmed via inspection using a high speed camera while performing pitch variation.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1839-1842
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• 2008

• Electronics and Telecommunications Trends
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• v.24 no.4
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• pp.126-134
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• 2009

기존의 AC 전력전달 기반의 데이터센터를 고효율의 DC 데이터센터로 변경에 관한 연구가 활발히 진행중이다. 그 중 랙 준위 DC 전원공급장치는 기존 데이터센터의 전력구조 변화 없이 랙 레벨에서 DC 전원을 서버에 공급하는 방식으로 기존 AC 데이터센터에 적용 가능한 최적의 기술이다. 본 논문은 ETRI가 개발한 데이터센터의 랙 준위 DC 전원공급장치 특징에 관한 내용을 담고 있다. 본 장치는 부하에 따라 효율을 최적으로 제어하는 지능적 제어 기법을 사용하며, 랙 준위 N+ 1 전력 이중화로 높은 안정성을 제공하고 있다. 또한 랙 준위 전력 및 랙 주위 온/습도정보의 실시간 웹 모니터링 기능을 제공하고 있다.