• 설비공학논문집
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• 제29권7호
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• pp.341-349
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• 2017

Formation and transportation of $CO_2$-hydrate slurry was conducted by circulating saturated water with $CO_2$ through a double-tube type heat exchanger which was cooled down by brine. The inner diameter and circulation length of the heat exchanger were 1 inch and 20 m, respectively. Water in tank was supersaturated by injected $CO_2$ and the operation pressure was maintained at 3,000 to 4,000 kPa with fluid-temperature of less than $9^{\circ}C$. $CO_2$ hydrate mass fraction was calculated based on density of $CO_2$-hydrate slurry mixture. Results showed that the $CO_2$-hydrate slurry could be circulated without blockage for 1 hr. Circulation status of the $CO_2$-hydrate slurry was also visualized.

• 설비공학논문집
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• 제13권12호
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• pp.1175-1183
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• 2001

Recently, a great attention has been paid to the ice thermal storage system for the purpose of energy saving and reduction in peak electrical demand. In the present study, it has been investigated the freezing behavior of several kinds of water solutions with nonionic surfactant. In order to prevent ice blockage in a cooled pipe, the amount and wall adhesion behavior of ice of the test fluids were observed experimentally under different concentration of water solution with surfactant, temperature of cooled wall, and the shear velocity of test fluids. The results showed that the size of ice crystal became smaller at higher shear velocity at wall. And the lowest limit of wall adhesion of ice in water solution with surfactant was found at 230 W/$m^2$ of heat flux.

• 항공우주시스템공학회지
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• 제16권5호
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• pp.17-25
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• 2022

액체로켓엔진의 중요한 특성인 연소 안정성, 연소효율 및 넓은 범위의 추력 조절 등에서 장점이 많은 핀틀 분사기를 설계 및 제작하여 초임계 조건에서 연소시험을 수행하였다. 핀틀 분사기는 추력 제어 및 제작성을 고려하여 직사각형의 1열 형상의 오리피스를 갖는 핀틀 분사기로 제작하였다. 핀틀 분사기의 연소성능 및 상용 분사기로써의 가능성을 검증하기 위해 TMR(Total Momentum Ratio)과 BF(Blockage Factor)를 변화하여 연소 특성을 분석하였다. 연소시험 결과 열유속은 TMR 증가에 따라 증가하는 경향이 나타났으며, 특성속도 효율은 TMR보다 BF에 영향을 받는 것으로 확인되었다. 따라서 TMR 변화에 둔감한 효율 특성을 갖는 1열 핀틀 분사기는 낮은 연료 차압 조건에서 높은 효율을 달성할 수 있다면, 가변 핀틀 분사기 설계 유연성이 높아질 수 있다.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.3990-4002
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• 2021

CSPACE (Core meltdown, Safety and Performance Analysis CodE for nuclear power plants) for a simulation of severe accident progression in a Pressurized Water Reactor (PWR) is developed by coupling of verified system thermal hydraulic code of SPACE (Safety and Performance Analysis CodE for nuclear power plants) and core damage progression code of COMPASS (Core Meltdown Progression Accident Simulation Software). SPACE is responsible for the description of fluid state in nuclear system nodes, while COMPASS is responsible for the prediction of thermal and mechanical responses of core fuels and reactor vessel heat structures. New heat transfer models to each phase of the fluid, flow blockage, corium behavior in the lower head are added to COMPASS. Then, an interface module for the data transfer between two codes was developed to enable coupling. An implicit coupling scheme of wall heat transfer was applied to prevent fluid temperature oscillation. To validate the performance of newly developed code CSPACE, we analyzed typical severe accident scenarios for OPR1000 (Optimized Power Reactor 1000), which were initiated from large break loss of coolant accident, small break loss of coolant accident, and station black out accident. The results including thermal hydraulic behavior of RCS, core damage progression, hydrogen generation, corium behavior in the lower head, reactor vessel failure were reasonable and consistent. We demonstrate that CSPACE provides a good platform for the prediction of severe accident progression by detailed review of analysis results and a qualitative comparison with the results of previous MELCOR analysis.

• 대한가정학회지
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• 제36권9호
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• pp.1-11
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• 1998

In this paper the Korean standards of clothing for firefighters were examined and analysed to improve the uniform's effectiveness. The results of the analysis are as follows: 1. The Korean standards for firefighters' uniforms first established in 1949 and were amended eleven times before 1983. The standards were reestablished in 1983 and had been amended four times by 1995. Recently there have been different causes of fire, and fires have become bigger and bigger. For these reasons, it is necessary to review the Korean standards for firefighters' uniforms. 2. The Korean standards are very different from those of Japan and USA. In Japan, firefighters' uniforms are classified by factors such as season and working conditions, while in Korea they are classified by factors such as sex and position. Furthermore, there are many items which are not mentioned in the Korean standards, such as ear covers and gloves. Textile materials are specified by brand names or company-designated item names. Classification of clothing items also needs to be esamined. 3. Such words as fire-proof, water-proof and heat-proof clothing just mean that the clothing blocks fire, water, or hear, and do not specifically include the meaning of protecting firefighters. Some word such as "firefighters' clothing" must be developed to imply all these types of blockage and protection. 4. Considering the rules of Korean orthography, the rules of romanization of borrowed words, and technical terms for clothing many technical words in the Korean standards for firefighters' uniforms are not appropriate, and need to be corrected and improved.

• 대한한의학방제학회지
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• 제12권1호
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• pp.29-77
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• 2004

After this study: I report the following result from it. 1. Beriberi is defined as sensory or motor disorder of leg with a painful-swelling and pyrexia. If it progress severely, the disease transmits to heart and cause numbness of the lower abdomen, vomiting, anorexia, palpitation, chest distress and confusion. 2. The external etiologic factors of Beriberi are wind-toxic pathogen, dampness, improper diet and climate sickness, the internal etiologic factors are deficiencies of the kidney, both Gi and blood and original vital energy. 3. The treatment of Beriberi is free-going of blockage, because it is a blocked disease. 4. Danggwiy-juntongtang and Ganghwar-dochetang is the most in the order of frequency of use. Mahwang-juagyongtang, Banha-juagyongtang, Daehwang-juagyongtang, Shinbi-juagyongtang are used in sequence. 5. The prescriptions of Beriberi are made up of the herbs that clear heat, for example, Ganghwar, Changchul, Mahwang and Bangpung, and the herbs that reinforces Gi, for example, Insam and Bakchul.

• 대한한의학원전학회지
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• 제23권1호
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• pp.1-10
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• 2010

Wi Syndrome(痿證) mainly occurs from fluid damages[津液損傷] caused by heat in Gi(氣) phase of the Five viscera, while it sometimes come from the outside. Although the symptoms are presented in the limbs, the disorder roots in the Five viscera, most deeply located in the human body, Therefore, to approach the disorder, we must apply differentiation of the Five viscera in diagnosis. The Lungs, as the head of the Five viscera control the production and distribution of bodily fluids in the body. Functional disorder of the Lungs bring about Wi Syndrome regardless of it being in the Gi phase. Also, psychological depression leads to Wi Syndrome, In other words, depression and uneasiness easily results in the state of Gi blocking and fluid exhaustion in this modern society where there is less manual labor and excessive use of the brain. Besides Gi blockage, the top muscle[宗筋] theory is another important mechanism in the occurrence of Wi Syndrome. Moreover, the disorder is related to Yangmyeong(陽明), which is the sea of food, Chungmaek(衝脈) which is the sea of meridian, in addition to Immaek(任脈), Dokmeak (督脈) and Deameak(帶脈) which are all involved in Wi Syndrome. In conclusion, the Wi Syndrome happens when various factors involved lose balance and harmony with each other.

• Asian-Australasian Journal of Animal Sciences
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• 제26권9호
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• pp.1347-1358
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• 2013

Membrane technology has revolutionized the dairy sector. Different types of membranes are used in the industry for various purposes like extending the shelf life of milk without exposure to heat treatment, standardization of the major components of milk for tailoring new products as well increasing yield and quality of the dairy products, and concentrating, fractionation and purification of milk components especially valuable milk proteins in their natural state. In the cheese industry, membranes increase the yield and quality of cheese and control the whey volume, by concentrating the cheese milk. With the advancement of newer technology in membrane processes, it is possible to recover growth factor from whey. With the introduction of superior quality membranes as well as newer technology, the major limitation of membranes, fouling or blockage has been overcome to a greater extent.

• 설비공학논문집
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• 제19권12호
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• pp.850-856
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• 2007

In a supercooled or capsule type ice storage system, aqueous solution (or water) may have trouble with non-uniform dissolution though the system contributes to the simplicity of system and ecological improvement. The non-uniform dissolution increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to observe the supercooled state, a cooling experiment was performed with pressurization to an ethylene glycol(EG) 3 mass% solution in stationary state. Also, the effect of the pressurization from 101 to 505 kPa to the dissolution of supercooled aqueous solution was measured with the dissolution time of the supercooled aqueous solution at a fixed cooling rate of brine. At results, the dissolution of supercooled point decreased as the pressure of the aqueous solution in the vessel increased. Moreover, the dissolution point increased as the heat flux for cooling increased.

• Nuclear Engineering and Technology
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• 제35권2호
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• pp.91-107
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• 2003

Since DBA(Design Basis Accidents) has been studied rather separately from SA(Severe Accidents) in the conventional nuclear reactor safety analysis, the thermal hydraulics during transition between DBA and SA has not been identified so much as each accident itself. Thus, in this study, the thermal hydraulic behavior from DBA to the commencement of SA has been experimentally and analytically investigated for the long-term cooling phase of LB-LOCA(Large-Break Loss-of-Coolant Accident). Experiments were conducted for both cases of the loop seal open and closed in an integral test loop, named as SNUF (Seoul National University Facility), which was scaled down to l/6.4 in length and 1/178 in area of the APR1400 (Advanced Power Reactor 1400MWe). The core mixture level was a main measured value since it took major role in the fuel heat-up rate, the location of fuel melting initiation and the channel blockage by melting material during SA. Experimental results were compared to MAAP4.03 to assess its model of calculating the core mixture level. MAAP4.03 overestimates the core two- phase mixture level because sweep-out and spill-over and the measures to simulate the status of loop seal are not included, which is against the conservatism. Thus, it is recommended that MAAP4.03 should be improved to simulate the thermal hydraulic phenomena, such as sweep-out, spill-over and the status of loop seal.