• International Journal of Fluid Machinery and Systems
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• 제8권1호
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• pp.46-54
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• 2015

Thrust-ring-pump is a kind of extreme-low specific speed centrifugal pump with special structure as numerous restrictions from thrust bearing and operation conditions of hydro-generator units. Because the oil circulatory and cooling system with thrust-ring-pump has a lot of advantages in maintenance and compactness in structure, it has widely been used in large and medium-sized hydro-generator units. Since the diameter and the speed of the thrust ring is limited by the generator set, the matching relationship between the flow passage inside the thrust ring (equivalent to impeller) and oil bath (equivalent to volute) has great influence on hydrodynamic performance of thrust-ring-pump. On another hand, the head and flow rate are varying with the operation conditions of hydro-generator units and the oil circulatory and cooling system. As so far, the empirical calculation method is employed during the actual engineering design, in order to guarantee the operating performance of the oil circulatory and cooling system with thrust-ring-pump at different conditions, a collaborative hydrodynamic design and optimization is purposed in this paper. Firstly, the head and flow rate at different conditions are decided by 1D flow numerical simulation of the oil circulatory and cooling system. Secondly, the flow passages of thrust-ring-pump are empirically designed under the restrictions of diameter and the speed of the thrust ring according to the head and flow rate from the simulation. Thirdly, the flow passage geometry matching optimization between thrust ring and oil bath is implemented by means of 3D flow simulation and performance prediction. Then, the pumps and the oil circulatory and cooling system are collaborative hydrodynamic optimized with predicted head-flow rate curve and the efficiency-flow rate curve of thrust-ring-pump. The presented methodology has been adopted by DFEM in design process of thrust-ring-pump and it shown can effectively improve the performance of whole system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.752-754
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• 1999

When we are trying to retrofit turbine control system from analog system to digital one, a new communication network is required to be contstructed. In this paper, we are going to introduce one example of economic communication network, which is reliable in operation from control room and field instruments to office and computer room. It will be installed in a power plant in the case of retrofiting control system of medium size steam turbine.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.802-809
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• 2010

KIMM(Korea Institute of Machinery and Materials ) and ROTEM have been leading development of the low to medium speed urban transit maglev for the past 20 years. The result of this long term national project is UTM-01 ( Urban Transit Maglev -01 ) in 1998 and UTM-02 in 2006 and the 6.1 km long double track maglev commercialization project in Inchon international airport from 2006 to 2012. In this paper the status of the maglev development for the past 20 years is reported. Design changes in key technologies - maglev bogies, secondary suspension system, levitation system, propulsion system, major power suppling equipments from UTM-01 system to that of commercialization project - are described.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.57-60
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• 2001

대부분의 대형마트의 경우, 효율적인 물류관리 시스템으로 물류 비용을 절감하고 있으나 중소형마켓의 경우 물류관리 시스템을 보유하고 있지 못하기 때문에 물류의 효율적 관리뿐만 아니라 가격경쟁에는 어려운 실정이다. 본 논문에서는 GPS를 사용하여 물류차량의 정보를 효율적으로 관리할 수 있는 시스템을 제한한다. 이 시스템은 물류차량의 위치를 실시간으로 수치지도에 매핑하고, 고객으로부터의 주문 정보를 수신하여 최적의 위치에 있는 차량에게 주문을 의뢰하여 물류비용의 최소화할 수 있는 시스템을 개발하였다.

• 조명전기설비학회논문지
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• 제17권3호
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• pp.80-86
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• 2003

본 논문에서는 육상의 지중전력케이블에 비해 유지보수가 힘들고 사고의 파급효과나 사고복구에 큰 어려움이 따르는 해저케이블을 대상으로 진단시험 및 유지보수에 대한 연구를 수행하였다. 본 연구의 목적은 사고위험이 높은 해저선로에 대한 경제적이고 효율적인 열화진단 및 유지보수에 있다. 진단시험 결과, 해저케이블의 열화정도는 매우 심각하며 열화가 계속 진전되고 있음을 확인하였다. 단말부 교체시공 후 재 진단시험을 실시한 결과, 전체적인 열화상태가 개선되었음을 확인하였으며 단말부 및 케이블 절연부에 대한 전기적 특성시험과 화학구조분석 시험 결과, 전체 케이블 시스템의 열화는 주로 단말부 열화에 기인함을 알았다. 상기 결과에 따라 본 연구에 사용된 진단기법 및 유지보수 절차가 해저케이블시스템의 경제적인 관리에 매우 효과적임을 학인하였다.

• 대한조선학회논문집
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• 제49권6호
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• pp.478-483
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• 2012

The speed performances of ice sea trial on the Arctic(2010 & 2011) area were shown different results depend on the ice floe size. Penetration phenomena of level ice was not happened on medium ice floe and tore up by the impact force because the mass of medium ice floe is similar to the mass of Araon which is Korean ice breaking research vessel and did not shut up by the ice ridge or iceberg. The sea trial on the Amundsen sea was performed at the big floe which is classified by WMO(World Meteorological Organization). Three measurements of ice properties and five results of speed trial were obtained with different ice thicknesses and engine powers. To evaluate speed of level ice trial and model test results at the same ice thickness and engine power, the correction method of HSVA(Hamburg Ship Model Basin) was used. The thickness, snow effect, flexural strength and friction coefficient were corrected to compare the speed of sea trial. The analyzed speed at 1.03m thickness of big floe was 5.85 knots at 10MW power and it's 6.10 knots at 1.0m ice thickness and the same power. It's bigger than the results of level ice because big floe was also slightly tore up by the impact force of vessel based on the observation of recorded video.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.589-596
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• 2008

Performance of a pulsed heat source high temperature inert gas plasma MHD electrical power generator, which can be one of the candidates of space-based laser-to-electrical power converter, is examined by a time dependent two dimensional numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally heated to about $10^4K$ pulsed-likely within short time(${\sim}1{\mu}s$) in a stagnant energy input volume, and the energy of high temperature inert gas is converted to the electricity with the medium of pure inert gas plasma without seeding. The numerical simulation results show that an enthalpy extraction ratio(=electrical output energy/pulsed heat energy) of several tens of % can be achieved, which is the same level as the conventional seeded non-equilibrium plasma MHD generator. Although there still exist many phenomena to be clarified and many problems to be overcome in order to realize the system, the pulsed heat source high temperature inert gas MHD generator is surely worth examining in more detail.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.169-172
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• 2004

Is entering in age that brand becomes consumer's goods purchase standard as income level is improved, dying injunction brand is trend that governing power in the world market is expanded as international economy does single market. Therefore, do to support market public information and marketing because do it so that may improve product level because introduces and operate system brand of our ceramics by ceramics market possession of advanced nation such as the United States of America, Japan, Britain and utilizes cooperation brand of medium and small enterprises product eternal generation and improves ceramics market competitive power in inside and outside of the country.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2006년도 고분자리싸이클링 심포지엄
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• pp.3-12
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• 2006

The main feature of these total technologies is that we can constitute the optimum treatment scheme fitting to the property of wastes, amount of wastes and energy requirement. For high moisture content wastes or biomass resources, high pressure steam process (MMCS) for crush, dry and deodorize wastes to produce high quality fertilizer of fuel is most appropriate. For dry or semi-dry solid wastes, the STAR-MEET system can be applied to produce low-BTU gases for power generation using duel fueled diesel engines of Stirling engines, and the REPRES and HyPR-MEET systems can be applied to produce hydrogen rich medium-BTU gas. For waste plastics and oils, liquefaction technology is best fit to produce light oil or kerosene equivalent fuel oils. These total technologies are completely different from the existent waste treatment technologies based on land-filling or incineration, and are expected to disseminate all over the world in the near future.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3726-3729
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• 2011

Biofilm formation is inevitable in a bioelectrochemical system in which microorganisms act as a sole biocatalyst. Cathodic biofilm (CBF) works as a double-edged sword in the performance of the air-cathode microbial fuel cells (MFCs). Proton and oxygen crossover through the CBF are limited by the robust structure of extracellular polymeric substances, composition of available constituents and environmental condition from which the biofilm is formed. The MFC performance in terms of power, current and coulombic efficiency is influenced by the nature and origin of CBF. Development of CBF from different ecological environment while keeping the same anode inoculums, contributes additional charge transfer resistance to the total internal resistance, with increase in coulombic efficiency at the expense of power reduction. This study demonstrates that MFC operation conditions need to be optimized on the choice of initial inoculum medium that leads to the biofilm formation on the air cathode.