• Journal of Energy Engineering
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• v.9 no.3
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• pp.250-260
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• 2000

유동층 연소기술은 다양한 연료의 사용과 SOx와 같은 공해물질의 배출제어가 용이하여 환경규제에 대한 대처능력이 우수한 발전방식으로 널리 적용되고 있는 추세이다. 국내에서도 동해화력 1,2호기(200MWe급)가 유동층 연소방식을 도입하여 운전중에 있으며, 국내 무연탄을 연료로 사용하는 최대 규모의 순환 유동층 보일러라 할 수 있다. 본 논문에서는 IEA-CFBC 모델을 이용하여 개발된 동해화력 순환유동층 성능모사 시뮬레이션 틀을 이용하여 여러 가지 운전변수 변화에 따른 성능예측을 수행하였으며, 특히, 연소로의 성능향상을 위한 방안의 일환으로 사이클론 개조를 수행하고 그에 따른 성능모사를 고찰하였다. 본 성능평가 결과 연소로내 전체 차압을 증가시키는 운전을 지향하는 것이 연소로내 희박상의 온도분포를 낮추고, 탈황효율을 증가시켜 운전 안정화에 기여하는 것으로 나타났다. 또한, 본 시뮬레이션 틀을 이용한 운전변수 변화에 대한 성능예측 결과 동해화력 운전 실측치와 잘 일치하는 것으로 고찰되었다.

• Journal of Hydrogen and New Energy
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• v.3 no.2
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• pp.1-7
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• 1992

New type of metal hydride heat pump (MHHP) combined with hydrogen compressor was constucted for cooling purpose. A model for calculating the coefficient of performance (COP) is presented for MHHP which consisted of two different stages (enforced and natural stage), and compared with the experimental results. A concept of adiabatic compression work is introduced in the model on the basis of Carnot reversible analysis and the dependence of COP on the various operational parameters is discussed.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.935-940
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• 2023

Digital-twin technology is emerging as an innovative solution for all industries, including manufacturing and production lines. Therefore, this paper optimizes all the energy used in a biomass plant based on unused resources. We will then implement a digital-twin prototype for biomass plants and evaluate its performance in order to improve the efficiency of plant operations. The proposed digital-twin prototype applies a standard communication platform between the framework and the gateway and is implemented to enable real-time collaboration. and, define the message sequence between the client server and the gateway. Therefore, an interface is implemented to enable communication with the host server. In order to verify the performance of the proposed prototype, we set up a virtual environment to collect data from the server and perform a data collection evaluation. As a result, it was confirmed that the proposed framework can contribute to energy optimization and improvement of operational efficiency when applied to biomass plants.

• Land and Housing Review
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• v.7 no.3
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• pp.131-136
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• 2016

The aim of this study was to improve the performance of hybrid energy harvesting block merge the vibrations and the pressure developed in the previous study. The power generation performance of the energy block improved in this manner was measured and compared with the energy performance of the products previously developed. In previous models, the center has placed a piezoelectric, the two sides had arranged a vibration applying electromagnetic inducing type. Improved model was disposed three in a row of three unit modules for one block. We change the design in the following way. That is, a unit module has been placed the upper piezoelectric body, the lower portion were arranged three electron donation. In laboratory conditions, the power generation performance evaluation results of the improved energy block is as follows. Once when the vibration, power generation was determined to 1.066W. When compared with previous studies, and power generation performance is improved up to 235%. When the vibration in a row 5, power generation was determined to 1.830W. When compared with previous studies, the performance is improved to 177%. The purpose of developing a hybrid energy block is intended to produce electricity by the pressure and vibration when a vehicle passes through the energy block installed in the car park the mouth portion. Electricity produced will try to take advantage of for the purpose of operating a guiding beacon and LED signage in the parking lot entrance. Therefore, it is determined that there is a need in the experiment to compare the performance of the power generation in the field.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.339-345
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• 2006

In this paper, a physically meaningful methodology which can assess the contribution of each vibration mode to various vibration response signals (displacement, velocity, acceleration) is developed. Based on these results, the problem of quantitative assessment of the relative importance of a structural system's vibrational modes is discussed. In addition, a direct method which ran assess the relative importance of each mode from uniformly sampled experimental data is also proposed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.154-157
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• 2010

본 논문에서는 비선형 동적해석법을 이용하여 감쇠기의 적용이 철골조 건물의 연쇄붕괴 방지에 미치는 영향을 평가하였다. 단자유도 구조물에서 감쇠비의 변화에 따라 폭발하중이 구조물의 응답에 미치는 영향을 분석하였고, 15층 3경간 철골조 건물에서는 일정한 감쇠비 하에서 경간을 6m, 9m, 12m로 달리 하면서 감쇠기 설치 효과를 비교하였다. 단자유도 시스템의 경우 감쇠비가 증가 할수록 폭발하중에 의한 진동이 빠르게 감소하고 변위의 감소폭도 커지는 경향을 보였다. 15층 철골조 건물에서도 역시 감쇠기를 설치할 경우 수직 처짐 및 초기 진동을 제어하는 효과가 있었다. 구조물의 경간이 증가하여 수직 변위가 증가 할수록, 감쇠기에 의해 소산된 에너지도 증가하기 때문에 수직 처짐 제어효과가 큰 것으로 나타났다.

• Progress in Medical Physics
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• v.16 no.2
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• pp.97-103
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• 2005

The energy spectra and dose calculations were performed for secondary neutrons from a 24 MV LINAC using MCNPX code (V2, 4, 0). The energy spectra for neutrons and photons emitted from the LINAC head, and absorbed dose to water were calculated in water phantom. The absorbed doses calculated with Monte Carlo were $0.66\~0.35$ mGy/photon Gy at the surface to d=5 cm, and calculated with interaction data was 0.52 mGy/photon Gy at the depth of electron equilibrium in water. We have shown that this work can be applied to dose estimation of neutrons from high energy LINAC through the comparison of our results with other results.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.3
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• pp.41-49
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• 2024

In this paper, we validate simulation results for the design optimization of a Superconducting Fault Current Limiter (SFCL) intended for use in Medium Voltage Direct Current systems (MVDC). With the increasing integration of renewable energy and grid connections, researchers are focusing on medium-voltage systems for balancing energy in new and renewable energy networks, rather than traditional transmission or distribution networks. Specifically, for DC distribution networks dealing with fault currents that must be rapidly blocked, current-limiting systems like superconducting current limiters offer distinct advantages over the operation of DC circuit breakers. The development of such superconducting current limiters requires finite element analysis (FEM) and an extensive design process before prototype production and evaluation. To expedite this design process, the design outcomes are assimilated using a Reduced Order Model (ROM). This approach enables the verification of results akin to finite element analysis, facilitating the optimization of design simulations for production and mass production within existing engineering frameworks.

• Journal of Radiation Protection and Research
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• v.37 no.1
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• pp.16-24
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• 2012

In the present study, a gamma-ray detector and associated signal processing circuit was developed for a side-absorber of a dual-mode Compton camera. The gamma-ray detector was made by optically coupling a CsI(Tl) scintillation crystal to a silicon photodiode. The developed signal processing circuit consists of two parts, i.e., the slow part for energy measurement and the fast part for timing measurement. In the fast part, there are three components: (1) fast shaper, (2) leading-edge discriminator, and (3) TTL-to-NIM logic converter. AC coupling configuration between the detector and front-end electronics (FEE) was used. Because the noise properties of FEE can significantly affect the overall performance of the detection system, some design criteria were presented. The performance of the developed system was evaluated in terms of energy and timing resolutions. The evaluated energy resolution was 12.0% and 15.6% FWHM for 662 and 511 keV peaks, respectively. The evaluated timing resolution was 59.0 ns. In the conclusion, the methods to improve the performance were discussed because the developed gamma-ray detection system showed the performance that could be applicable but not satisfactory in Compton camera application.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.175-182
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• 2015

A methodology to determine the most conservative initial condition based on random sampling of operation parameters is established, in which a best-estimate computer code is adopted to minimize the conservatism in code models. To validate the applicability of the suggested method, safety evaluation for a transient of loss of condenser vacuum in a pressurized water reactor is performed. One-hundred different initial conditions are generated by MOSAIQUE program automatically and the peak pressure for the most conservative case is determined from transient analyses. The safety margin obtained with the new approach is almost equivalent to the values determined with the existing methodologies. It is found that the time and human resources required for the safety evaluation could be reduced with the suggested approach.