• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.547-552
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• 1998

The standard RELAP5/MOD3.2 code were assessed with the condensation experiment in the presence of noncondensable gas in a vortical tube of PCCS of CP-1300. There are two wall film condensation models, the default model and the alternative model, in RELAP5/MOD3.2. The experimental apparatus was modeled with the two models, md simulations were performed for several sub-tests to be compared with the experimental results. In overall sense the simulation results showed that the default model of RELAP5/MOD3.2 under-predicts the heat transfer coefficients, while the alternative model over-predicts them throughout the condensing tube.

• 전기학회논문지P
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• 제63권4호
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• pp.241-247
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• 2014

This paper propose a variable parameter estimations of five-phase squirrel-cage induction motor(IM) for speed control system. In order to high performance control of AC motor using a field oriented control(FOC) and direct torque control(DTC) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, rotor position, speed estimation, and so on. We are suggest a analyzed estimation results of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental of variable input power frequency. There are results of stator winding test, no-load test, locked-rotor test, variable actual load test, and estimated parameters of equivalent circuits using manufactured experimental apparatus by IEEE Standard Test Procedure for Polyphase Induction Motors and Generators 112-2004.

• Steel and Composite Structures
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• 제38권2호
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• pp.177-187
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• 2021

The effect of nanoparticle volume fraction on the elastic properties of a polymer-based nanocomposite was experimentally investigated and the obtained results were compared with various existing theoretical models. The nanocomposite was consisted of high density polyethylene (HDPE) as polymeric matrix and 0, 0.5, 1 and 1.5 wt.% multi walled carbon nanotubes (MWCNTs) prepared using twin screw extruder and injection molding technique. Nanocomposite samples were molded in injection apparatus according to ASTM-D638 standard. Therefore, in addition to morphological investigations of the samples, tensile tests at ambient temperature were performed on each sample and stress-strain plots, elastic moduli, Poisson's ratios, and strain energies of volume units were extracted from primary strain test results. Tensile test results demonstrated that 1 wt.% nanoparticles presented the best reinforcement behavior in HDPE-MWCNT nanocomposites. Due to the agglomeration of nanoparticles at above 1 wt.%, Young's modulus, yielding stress, fracture stress, and fracture energy were decreased and Poisson's ratio and failure strain were increased.

• 한국지반환경공학회 논문집
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• 제17권6호
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• pp.23-31
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• 2016

최근 들어 우리나라에 이상한파가 자주 발생하고 있으며, 이로 인해 지반에서는 동상에 따른 도로, 철도, 사면과 같은 구조물을 대상으로 지반변형에 따른 문제가 야기되고 있다. 동상현상은 가장 대표적인 동토지반의 공학적 특성으로, 구조물 설계에 있어서 동착 및 크리프 현상과 함께 주요한 설계정수로서 고려된다. 그러므로 극한지 지반구조물 설계에 관한 연구를 위해서는 동상현상에 대한 기초적 연구가 선행되어야 한다. 이미 다양한 동상 관련 실험장비가 개발되어 연구에 활용되고 있지만, 기존의 동상 연구를 위한 실험장비들은 기초의 설계정수로서 동상현상을 분석하기에는 한계점이 나타난다고 판단된다. 국내에는 동상을 실험적 모사하기에는 필요한 장치와 냉동챔버의 고비용으로 시험방법 및 기준이 전무한 실정이다. 이에 본 논문에서는 다양한 방법으로 동결-융해를 모사할 수 있는 투명 온도제어형 삼축셀 을 소개하고자 한다. 새롭게 개발된 동결-융해 실험장치를 활용해 동상 실내실험을 수행하였으며, 본 장치를 활용한 실내실험법을 제안하고자 한다.

• 열처리공학회지
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• 제5권4호
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• pp.224-232
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• 1992

Coolingability of coolants is important factor in cooling processor heat treatment of steel. Using standard apparatus and method defined in the Korean Industrial Standard three different shapes of probe were designed, ie, cylinderical, spherical and square on shape with same volume of standard probe. Distilled water and sodium aquious solutions with different concentration of NaOH, NaCl and $Na_2CO_3$ were examined. Estimation of coolingability of each quenchants for the probes of cylinderical, spherical or square shape, the cooling rate is greater square, cylinder and sphere in order. Coolingability of sodium aquious solution of NaCl, $Na_2CO_3$ and NaOH is found generally greater then that of distilled water. Effectiveness of ingredients is in the order of $Na_2CO_3$, NaOH and NaCl. In both solutions coolingability increases in 20%, 5%, and 10%in order. Analytical results obtained from Finite Element Method were compared with experimental ones and found as practically satisfactional.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1548-1553
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• 2003

An experimental study of the absorption process of water vapor into a lithium bromide solution was performed. For the purpose of development of high performance absorption chiller/hater utilizing lithium bromide solution as working fluid, it is the most effective to improve the performance of absorber with the largest heat transfer area of the four heat exchangers. The experimental apparatus was composed of a plate type absorber which can increase the heat exchange area per unit volume to investigate more detail characteristics instead of the conventional type, horizontal tube bundle type. The size of plate absorbers were made for $0.4m{\times}0.6m$ and the design object of a refrigeration capacity was lRT. In this experiment, three kind plate absorbers which were flat plate, dimple plate and groove plate were used. The results were less than the design object values, that is, the refrigeration capacity was about $0.3{\sim}0.4RT$ and the overall heat transfer coefficient was $500{\sim}600kcal/m^2h^{\circ}C$ at the standard conditions.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2004년도 춘계 학술발표회 논문집
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• pp.201-212
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• 2004

An experimental study of the absorption process of water vapor into a lithium bromide solution was performed. For the purpose of developing high performance absorption chiller/hater utilizing lithium bromide solution as working fluid, it is important to improve the performance of absorber with the larger heat transfer area of the four heat exchangers. The experimental apparatus was composed of a plate type absorber which could increase the heat exchange area per unit volume to investigate more detail characteristics instead of the conventional type, that is, horizontal tube bundle type. The size of plate absorbers were made for 0.4m$\times$0.6m and the design objective of a refrigeration capacity was 1RT. In this experiment, three kinds of plate absorbers namely flat plate, dimple plate and groove plate were used. The obtained results were less than the design objective values, that is, the refrigeration capacity was about 0.3 ～0.4RT and the overall heat transfer coefficient was 500～600 kcal/$m^2$h$^{\circ}C$ at the standard conditions.

• 한국항공우주학회지
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• 제35권6호
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• pp.489-495
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• 2007

표준 동역학 모델의 피치 동안정미계수를 측정하기 위한 실험적 연구가 아음속 풍동에서 수행되었다. 모델은 트리거 신호가 주어지면 직류형 서보모터에 의하여 일정한 진폭과 주파수로 상, 하 피치운동을 시작하며, 동시에 25 사이클 동안의 데이터가 자료획득시스템에 저장된다. 동안정미계수 계산에 필요한 위상차는 기준입력 신호와 모델의 무게중심에 장착된 밸런스로부터 나오는 출력신호의 최대 정점과의 위상변화로부터 얻어졌다. 또한 Stabilator의 동안정미계수에 대한 영향은 조종면을 변위시키면서 측정하였다. 본 실험을 위해 독창적으로 제작된 모델의 구동장치 및 실험장치가 다른 연구와 다른데도 불구하고 실험결과는 받음각 변화에 따른 동안정미계수의 변화 경향성이 TPI, NAE, 그리고 FFA의 연구결과와 비교적 잘 일치함을 확인하였다.

• 산업기술연구
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• 제21권A호
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• pp.273-278
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• 2001

In this study, we prepared nano-sized $TiO_2$ particles for various process variables by the diffusion flame reactor and we collected $TiO_2$ particles by thermophoresis. It is found that the size of $TiO_2$ particles increases, as the flame temperature or the inlet $TiCl_4$ concentration increase or the total gas flow rate decreases. We investigated the photo-degradation of phenol wish the prepared $TiO_2$ particles. We found the optimum amounts of $TiO_2$ photocatalysts for our experimental apparatus and investigated the photo-degradation efficiencies of phenol, changing the process variables such as size of $TiO_2$ photocatlysts, phase ratio of rutile/anatase, concentration of phenol, input ratio of $O_2$. Degradation efficiencies of phenol were almost 95% in 15 minutes for the standard conditions of our experiments.

• 대한기계학회논문집
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• 제13권3호
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• pp.419-423
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• 1989

본 연구에서는 담금유의 냉각능에 관한 상세한 연구는 우리나라에서는 아직 미비한 상태에 있으나, 저자 등은 제1보에서 서술한 실험장치 및 은시편을 사용하여 여러 광.식물성유의 냉각곡선을 구하고, 이로부터 냉각성능을 나타내는 파라미터들을 구하여, 객관적인 냉각성능을 평가하였다.