• 자원리싸이클링
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• 제12권3호
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• pp.25-30
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• 2003

본 연구의 목적은 실리콘웨이퍼의 절단공정에서 발생한 폐슬러리와 폐망간전지에서 발생하는 흑연봉을 각각 규소 및 탄소의 출발물질로 사용하여 가스터빈 부품, 열교환기 등에 사용되는 탄화규소(SiC)를 합성하는 연구를 수행하였다. 실리콘웨이퍼의 절단공정에서 발생하는 폐슬러리로부터 비중차이에 의한 선별과 자력선별 등에 의해 정제된 규소와 탄화규소를 얻을 수 있었으며, 폐망간전지를 해체하여 얻은 탄소봉으로부터 수세와 분쇄를 통하여 탄소분말을 얻을 수 있었다. 탄화규소의 합성은 규소와 당량비의 탄소분발을 혼합하여 1$600^{\circ}C$이상의 온도에서 아르곤 분위기와 진공분위기 하에서 2시간 유지시켰을 때 이루어졌으며, 이때 합성된 탄화규소의 순도는 99% 이상이었다.

• 한방안이비인후피부과학회지
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• 제14권2호
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• pp.207-223
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• 2001

The Wonyenaejang is equivalent to the (senile)cataract in western medicine. The word cataract is used to describe the natural lens that has turned cloudy. As the natural lens of the eye becomes cloudy, it does not allow light to pass through it. Cataracts usually start as a slight cloudiness that progressively grows more opaque. As the cataract becomes more mature(increasingly opaque and dense), the retina receives less and less light. The light that does reach the retina becomes increasingly blurred and distorted. This causes gradual impairment of vision. If left untreated, cataracts can cause needless blindness. Although there are many kinds of cataracts, a senile cataract is the most common one. We chose the oriental medicine textbooks and the oriental medicine journals that were dealing with the symptoms, etiology, and internal/external treatments. The results were as follows : 1. The main causes of this disease are weak liver and kidney, burning up of the wind and heat in the liver and gall, weak spleen and stomach. 2. As the internal treatment of the Cataract, Geegukjihwangtang is mostly prescribed. 3. As the external treatment of the Cataract, (l) In the field of medicine for external application is commonly prescribed (2) In the field of drug action, frequently used treatments are as follows. emission of the evil, alleviation of fever, removal of lump of blood, and the medicine for external applications. (3) In the field of four Qi, cold medicine is commonly prescribed. (4) In the field of five tastes, bitter/hot/sweet mdicine are commonly prescribed. (5) In the field of toxicity, non-togic medicine is commonly prescribed. (6) In the field of channel distribution, most of the medicine belong to liver channel.

• Nuclear Engineering and Technology
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• 제41권6호
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• pp.831-840
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• 2009

In order to evaluate the start-up behavior and to identify, through abnormal operation occurrences, the transient behaviors of the Sulfur Iodine(SI) process, which is a nuclear hydrogen process that is coupled to a Very High Temperature Gas Cooled Reactor (VHTR) through an Intermediate Heat Exchanger (IHX), a dynamic simulation of the process is necessary. Perturbation of the flow rate or temperature in the inlet streams may result in various transient states. An understanding of the dynamic behavior due to these factors is able to support the conceptual design of the secondary helium loop system associated with a hydrogen production plant. Based on the mass and energy balance sheets of an electrodialysis-embedded SI process equivalent to a 200 $MW_{th}$ VHTR and a considerable thermal pathway between the SI process and the VHTR system, a dynamic simulation of the SI process was carried out for a sulfuric acid decomposition process (Second Section) that is composed of a sulfuric acid vaporizer, a sulfuric acid decomposer, and a sulfur trioxide decomposer. The dynamic behaviors of these integrated reactors according to several anticipated scenarios are evaluated and the dominant and mild factors are observed. As for the results of the simulation, all the reactors in the sulfuric acid decomposition process approach a steady state at the same time. Temperature control of the inlet helium is strictly required rather than the flow rate control of the inlet helium to keep the steady state condition in the Second Section. On the other hand, it was revealed that the changes of the inlet helium operation conditions make a great impact on the performances of $SO_3$ and $H_2SO_4$ decomposers, but no effect on the performance of the $H_2SO_4$ vaporizer.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.147-158
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• 2017

Among the energy consumption in building, the heating energy takes the largest part. Therefore, it is important to minimize the heat energy loss in building for the reduction of overall energy use in construction. The most important points for the minimization of energy loss in building are insulation and airtightness. Especially, in wood houses, airtightness is very important for energy saving as well as increase of durability. However, the researches on airtightness of wood buildings have been started recently and are very deficient especially in Korea. In this study, air leakage properties and airtightness performance were evaluated for light-frame wood houses built in Daejeon and Chungnam area. Total 7 houses were evaluated, among which four houses (Case 1 to Case 4) were in the construction stage before interior finish and the other three houses (Case 5 to Case 7) were after completion of construction work. The tests for airtightness were conducted by pressurization-depressurization method, and the factors included in the measurements includes air leakage rate at 50 Pa (CMH50), air change rate at 50 Pa (ACH50), equivalent leakage area (EqLA) and EqLA per floor area. As a result of this study, key air leakage points in wood houses were found to be the gaps between floor and wall, the holes for wiring and plumbing, the double glasses windows and the entrance doors. The average value of ACH50 for the houses after completion of construction work was $3.5h^{-1}$ that was similar to Europe standard ($3.0h^{-1}$). ACH50 was proportional to EqLA per floor area but inversely proportional to the internal volume, the net floor area and the area of window.

• 자원환경지질
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• 제18권2호
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• pp.151-157
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• 1985

Events detected by the KIER microearthquake network operated in the Southern Part of Korea for 265 days in 1982~1984 were reviewed, and some of them were identified to be a dynamite explosion from several construction sites. The purpose of the present work is to determine the crustal structure of the Southern Korea using the time-destance data obtained from such explosion seismic records. The time·distance data can be well explained by a crustal model composed of four horizontal layers of which thickness, p and s-wave velocity ($V_p$ and $V_s$) are characterized as follows. 1st layer (surface) ; 0~2km, $V_p=5.5km/sec$, $V_s=3.3km/sec$ 2nd layer (upper crust) ; 2~15km, $V_p=6.0km/sec$, $V_s=3.5km/sec$ 3rd layer (lower crust) ; 15~29km, $V_p=6.6km/sec$, $V_s=3.7km/sec$ 4th layer (upper mantle) ; 29km~ , $V_p=7.7km/sec$, $V_s=4.3km/sec$ The relatively shallow crust·mantle boundary and low $P_n$ velocity compared with the mean values for stable intraplate region are noteworthy. Supposedely, it is responsible for the high heat flow in the South-eastern Korea or an anomalous subterranean mantle. The mean $V_p/V_s$ ratio calculated from the relation between p-wave arrival and s-p arrival times appears to be 1.735 which is nearly equivalent to the elastic medium of ${\lambda}={\mu}$. However, the ratio tends to be slightly larger with the depth. The ratio is rather high compared with that of the adjacent Japanese Island, and the fact suggests that the underlying crust and upper mantle in this region are more ductile and hence the earthquake occurrences are apt to be interrupted. As an alternative curstal model, a seismic velocity structure in which velocities are successively increased with the depth is also proposed by the inversion of the time·distance data. With the velocity profile, it is possible to calculate a travel time table which is appropriate to determine the earthquake parameters for the local events.

• 통합자연과학논문집
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• 제4권1호
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• pp.44-57
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• 2011

In general, heavy rainfall in Korea is mostly associated with inflow of 850hPa low-level jet. It transports abundant heat and moisture flux to the Changma front. In this study, synoptic characteristics of heavy rainfall in Korea from a case study is examined by classifying heavy rainfall cases with synoptic patterns, in particular distribution of upper- and low-level jets, western North Pacific high, and moisture flux. The surface and upper-level weather charts including auxiliary analysis chart and radar and satellite images obtained from the Korea Meteorological Administration, and 500hPa geopotential heights from NCEP/NCAR are used and then KLAPS is applied to understand the local atmospheric structure associated with heavy rainfall. Results show that maximum frequency in 60 heavy rainfall cases with more than 150mm/day appears in the Changma type of 43 cases (a proportion in relation to a whole is 52%) including the combined Changma types with typhoon and cyclone. As indicated in previous studies, most heavy rainfall cases are related to inflow of low-level jet. In addition, synoptic characteristics based on the analyses of weather charts, radar and satellite images, and KLAPS in heavy rainfall case of 12 July, 2009 reveal that the atmospheric vertical structure in particular equivalent potential temperature favorable for effective inflow of warm and moist southwesterly into the Changma front is linked to large potential instability and the strong convergence accompanied with low-level jet around Suwon contributes to atmospheric upsliding along the Changma front, producing heavy rainfall.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2311-2320
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• 2022

The main outcomes of the experiments H2P6 performed in the thermal-hydraulics large-scale PANDA facility at PSI in the frame of the OECD/NEA HYMERES-2 project are presented in this article. The experiments of the H2P6 series consists of two PANDA tests characterized by the activation of three (H2P6_1) or one (H2P6_2) cooler(s) in an initially stratified and pressurized containment atmosphere. The initial stratification is defined by a helium-rich region located in the upper part of the vessel and a steam/air atmosphere in the lower part. The activation of the cooler(s) results i) in the condensation of the steam in the vicinity of the cooler(s), ii) the corresponding activation of large scale natural circulation currents in the vessel atmosphere, with the result of iii) the re-distribution and mixing of the Helium stratification initially located in the upper half of the vessel and iv) the continuous pressure decay. The initial helium layer represents hydrogen generated in a postulated severe accident. The main question to be answered by the experiments is whether or not the interaction of the different, localized cooler units would be important for the application of numerical methods. The paper describes the initial and boundary conditions and the experimental results of the H2P6 series with the suggestion of simple scaling laws for both experiments in terms of i) the temperature difference(s) across the cooler(s), ii) the transient steam and helium content and iii) the pressure decay in the vessel. The outcomes of this scaling indicate that the interaction between separate, closely localized units does not play a prominent role for the present experiments. It is therefore reasonable to model several units as one large component with equivalent heat transfer area and total water flow rate.

• 한국식품영양과학회지
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• 제44권4호
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• pp.579-585
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• 2015

본 연구에서는 커피 생두를 오디 추출액에 2~6시간 침지시켜 오디 침지 커피를 제조하고 이화학적 특성, 항산화 활성, 소비자 기호도 등의 품질 특성을 조사하였다. 오디 침지 커피는 대조군보다 신맛이 더 강하였다. 가용성 고형분 함량 및 갈색도는 오디 침지 커피가 대조군보다 낮았다. 오디 침지 커피는 대조군보다 높은 a값(적색도) 및 b값(황색도)을 보여 일반 커피색보다 주황빛을 띠었다. 항산화 활성은 오디 침지 커피가 대조군보다 유의적으로 높았으나(P<0.05), 침지 시간에 따라 비례하지는 않았다. 총 폴리페놀 함량은 2H 및 4H에서 가장 높았으며, 총 플라보노이드 함량은 4H 및 6H에서 가장 높았다. 통계적으로 4H에서 DPPH, FRAP, ORAC의 항산화 활성, 총 폴리페놀 함량, 총 플라보노이드 함량이 가장 높았으며, 이는 4시간 침지 오디 침지 커피(4H)가 항산화 활성이 가장 우수한 커피로 여겨진다. 소비자 기호도 조사에서 4H가 가장 높은 전반 기호도를 보여주었으며, 색, 향, 풍미, 쓴맛에서도 높은 기호도를 가지는 것으로 평가되었다. 군집분석을 통해서 소비자는 오디 침지 커피를 좋아하는 약 61%의 소비자와 대조군을 좋아하는 약 39%의 소비자로 나누어졌다. 군집분석 결과는 오디 침지를 통한 기능성 커피의 시장성을 보여준다. 이화학적 특성, 항산화 활성, 소비자 조사 결과를 종합하여 볼 때, 4시간의 침지 시간이 오디 커피 제조에 가장 적합한 것으로 판단된다.

• Korean Chemical Engineering Research
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• 제52권6호
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• pp.706-712
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• 2014

폭약은 높은 에너지를 포함하는 반응성 물질이며 폭발이 발생할 경우 강한 빛, 높은 열, 소음 및 고압을 발생시킨다. 폭발 지점 주변의 손상은 대부분 높은 과압과 폭풍파에 영향을 받는다. 따라서 폭발에 의한 압력 및 폭풍파의 분석이 매우 중요하다. 본 연구에서는 HMX와 같은 고폭화약의 최대 과압 및 폭풍파 속도를 분석하였다. 먼저 HMX 폭발에 관하여 4가지 경우를 선정하고 폭발현상을 모델링하였으며 HMX의 양에 따른 폭발시뮬레이션을 통하여 최대 과압 및 폭풍파 속도를 도출하였다. 또한, 폭발이 Geometry 중심에서 일어난다고 가정하고 계산된 과압과 폭풍파 속도로부터 폭심에서 인접해 있는 위치의 영향을 분석하였다. 대조군으로 이용된 TNT도 함께 시뮬레이션 및 분석하였으며 HMX 시뮬레이션 결과와 비교함으로써 HMX의 상대적인 과압 및 폭풍파속도를 확인하였다. 본 연구는 HMX가 포함된 복합화약이 폭발하였을 경우 최대 과압 및 폭풍파속도 산정 시 기초데이터로 활용할 수 있다.

• 한국화재소방학회논문지
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• 제26권5호
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• pp.41-47
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• 2012

첨단산업기술인 반도체, LCD 등 제조의 핵심공정인 클린룸은 생산제품의 성능 및 품질에 절대적인 영향을 미치는 가장 중요한 공정이다. 그러나 국내는 방화공학적인 측면에서 과학적이고 종합안전대책에 대한 체계적인 연구가 제대로 이루어지지 않고 있다. 본 연구는 LCD 제조공정 클린룸에 설치하는 제연시스템의 성능 및 문제점을 파악하여 이에 대한 개선방안을 도출하기 위하여 여러 시나리오를 고려한 화재시뮬레이션과 피난시뮬레이션을 통하여 분석하였다. LCD 제조공정의 클린룸 화재 및 연기확산에 대하여 분석한 결과 화재시 공조기의 연동정지는 반드시 필요하며 연기의 부력을 고려하여 FAB 상부에 배연을 할 수 있도록 하여야 한다. 또한 대규모 클린룸의 경우 화재특성상 스프링클러헤드의 집열 성능이 떨어지므로, 조기반응형 헤드의 설치 및 작동시간을 빠르게 하기 위한 보조장치를 설치하여야 한다. 특히, 대공간 클린룸은 자동화 공정으로 거주밀도가 낮지만, 복잡한 생산장비의 배치와 방진복을 착용하고 근무해야하는 환경특성 때문에 화재시 피난안전성능 확보가 어렵기 때문에 공정 내 위험요소의 철저한 관리 및 주기적인 교육과 훈련이 필요하며, 방재선진국의 기준에 준하는 수준의 국내 관련기술 기준을 정립할 필요가 있다.