• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.824-829
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• 2000

The industries use polymer materials for many purposes because they have many merits. But these materials' costs take up too much proportion in overall cost of products that use these materials as their major material. So it is very economical for polymer industries to reduce these costs. Microcellular foaming process appeared in 1980's to solve this problem and it proved to be quite successful. This process uses inert gases such as CO2, N2. As these gases are dissolved into polymer matrices. many properties are changed. Glass transition temperature is one of these properties. DSC, DMA are devices that measures this temperature, but these are not sufficient to measure the temperature of polymer containing gas. In this paper, we devised a new tester that uses magnetism. We used this device to acquire data of the change of glass transition temperature and made Cha-Yoon model that can predict the change of glass transition temperature. Using this model, the change of this temperature can be estimated as a function of weight gain of gas. Cha-Yoon model proved that Chow's model is inappropriate to predict the change of glass transition temperature of polymer matrices containing gas.

• Journal of the Korean Society of Visualization
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• v.17 no.1
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• pp.78-84
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• 2019

A gas turbine is the main equipment of a power plant that generates electricity by high-speed rotation of the rotor in a high-temperature environment. In particular, in the case of medium to large-sized gas turbines, the rotor is composed of a plurality of stages, and each component is exposed to different physical environments. Especially, in the case of the tip clearance of the turbine, it is a very important factor in the performance of the design items and the operation of the stable turbine, and a design considering the physical behavior of all major parts should be done. In this study, we will discuss the process of visualizing the physical behavior of turbine operating conditions and the method of designing tip clearance for stable operation by using commercial finite element analysis program for gas turbine assembly model and single product.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.87-101
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• 2012

In gas industries, the potential risks of serious accidents have been increased due to high technology application and process complexities. Especially, in case of gas-related accidents, the extent of demage is out of control since gas plants handle and produce combustible, flammable, explosive and toxic materials in large amounts. The characteristics of this kind of disaster is that accident frequency is low, while the impact of damage is high, extending to the neighboring residents, environment and related industries as well as employees involved. The hydrogen gases treated important things and it used the basic material of chemical plants and industries. Since 2000, this gas stood in the spotlight the substitution energy for reduction of the global warming in particular however it need to compress high pressure(more than 150 bar.g) and store by using the special cylinders due to their low molecular weight. And this gas led to many times the fire and explosion due to leak of it. To reduce these kinds of risks and accidents, it is necessary to improve the new safety management system through a risk management after technically evaluating potential hazards in this process. This study is to carry out the quantitative risk assesment for hydrogen filling plant which are very dangerous(fire and explosive) and using a basic materials of general industries. As a results of this risk assessment, identified the elements important for safety(EIS) and suggested the practical management tools and verified the reliability of this risk assessment model through case study of accident.

• Journal of the Korean Institute of Gas
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• v.9 no.3 s.28
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• pp.15-20
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• 2005

Recently, Environmental and Safety Management is approaching in order to reduce the loss cost of accidents in effect, efficiency, excellency. In the side that is a large production enemy of the industrialization times, Most companies are focused on decreasing the loss that can let their companies grow healthily than a productivity improvement. The this study analyzed a matter asked f3r basic requirements and continuous development of ISO14001, OHSAS18001, PSM, Responsible Care operating in petro-chemical industries basically, and developed a LCMCI(the Loss Control Management system for Continuous Improvement of the Petro-chemical Industries) fer continuous development of petro-chemical companies in order to be able to continuously manage a loss.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.543-544
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• 2015

GIS(Gas Insulated Switchgear:가스절연 개폐장치)는 절연성능이 뛰어난 $SF_6$가스로 절연되어 초고압 전력의 제어(차단,투입)를 담당하는 중요한 장치이다. GIS는 절연성능을 검증하기 위하여 현장 운전전에 공장검수시험(내전압시험)과 현장 가압 시험을 수행한다. 이 때 GIS의 조립/운반/설치의 오류로 인한 절연성능 저하로 절연파괴(내부아크)가 발생될 수 있다. 그러나 GIS는 $SF_6$가스로 밀폐되어 있어 절연파괴를 정확히 알 수 없을 뿐만 아니라 사고 위치를 확인하기 어렵다는 단점을 가지고 있다. 따라서 본 논문에서는 이런 문제를 해결하기 위하여 GIS 내부에서 발생되는 사고를 신속하게 탐지하고 위치를 정확하게 표정할 수 있도록 개발된 GIS 절연파괴 위치 추정 시스템의 현장 적용연구를 수행하였다. 이를 통해 GIS 절연파괴 위치 추정 시스템의 성능을 확인하였다.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.38-43
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• 2005

The present study is concerned with the numerical analysis of the sloshing impact pressure of the Liquefied Natural Gas (LNG) carriers in rough sea. The reliable predictions of the both random tank motions in irregular waves and violent fluid flow in the LNG tanks are required for practical sloshing analysis procedure of LNG carriers. The three-dimensional numerical model adopting SOLA-VOF scheme is used to predict violent free surface movements of LNG tank in irregular motions. For accurate input motion of tank, a three-dimensional panel method program called SSMP (Samsung Ship Motion Program) is applied for seakeeping analysis. Comparison studies of sloshing analysis are carried out for No.2 tank of 138K and 205K LNG carriers to verify the safety of the LNG containment system of the proposed 205K large LNG carrier.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1284-1285
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• 2006

We reported a P/M soft magnetic material with core loss value of $W_{10/1k}=68W/kg$, which is lower than that of 0.35mm-thick laminated material, by using high purity gas-atomized iron powder. Lack of mechanical strength and high cost of powder production are significant issues for industrial use. In order to achieve both low core loss and high strength by using inexpencive powder, the improvement of powder shape and surface morphology and binder strength was conducted. As the result, the material based on water-atomized powder with 80 MPa of TRS and 108 W/kg of core loss (W10/1k) was achieved.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1060-1062
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• 2003

In this study, an insulation design program which can calculate electric field of the GIS bus parts easily was developed. It also can evaluate the insulation safety depending on gas density. For bus parts of $1{\varphi}$ GIS, it was intended to provide a optimal diameter of a conductor and an enclosure automatically for the convenience of GIS insulation designer. This program was coded by Visual Basic and electric field was calculated by the Charge Simulation Method(CSM), which is one of the most accurate method for an electric field analysis.

• Clean Technology
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• v.7 no.1
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• pp.81-88
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• 2001

Limestone has been used as absorbent in the FGD(Flue Gas Desulfurization) system, the DeSOx system of thermal power plant. This study investigated the desulfurization characteristics of the two different limestones, 325mesh and 200mesh particle size. Experimental analysis showed that the dissolving rate of limestone became much slower as the particle size increased. But the desulfurization efficiency depended on the L/G(liquid/gas) ratio and slurry pH regardless of the limestone particle size. The quality of gypsum produced in the FGD process increased as the limestone particle size or the slurry pH decreased. To reduce the cost of absorbent, the mixed limestone which were composed of 200 and 325mesh limestone with 5 different ratios were tested.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.415-421
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• 2013

This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Doosan Heavy Industries. The design procedure mainly consists of three parts: namely, flowpath design, airfoil design, and 3D performance calculation. To design the optimized flowpath, through-flow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and hade angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2D airfoil planar sections are designed carefully, followed by 2D B2B NS calculations. The designed planar sections are stacked along the spanwise direction, leading to a 3D surfaced airfoil shape. To consider the 3D effect on turbine performance, 3D multistage Euler calculation, single row, and multistage NS calculations are performed.