• 현장농수산연구지
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• 제20권1호
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• pp.55-66
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• 2018

하절기 하우스 온도환경의 효율적 제어는 온실의 주년재배와 고도 활용을 위한 가장 중요한 당면과제이다. 본 연구는 여름철 지역별 하우스 증발냉각을 위한 설계 기준안으로서 9개 지역(서울, 서산, 대전, 부산, 제주, 광주, 대구, 전주, 진주)의 VETH 선도를 작성하여 제시하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.261-266
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• 2003

포일 베어링은 공기의 점성과 포일 형태의 구조물을 이용하는 비접촉 베어링으로서, 구름베어링에 비하여 별도의 윤활장치가 필요 없고, 무한수명이 가능하며, 구름베어링을 사용할 수 없는 초고속 회전체와 50$0^{\circ}C$ 이상의 고온 환경에도 적용이 가능하다는 장점이 있다. 최근에는 전통적으로 널리 사용되어 왔던 소형 터보기기 분야뿐만 아니라, 소형 가스터빈 엔진과 같이 극한 온도 조건에서도 작동할 수 있는 포일 베어링에 대한 연구가 활발하게 진행되고 있다. 본 논문에서는 포일 공기 베어링 원리에 대한 소개와 함께, 현재 당사에서 볼베어링을 사용하여 개발 중인 65마력급 무인기용 터보샤프트 엔진의 고온부 베어링으로 적용하기 위한 가능성 연구를 수행하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.9-9
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• 2011

There has been strong demand for novel nonvolatile memory technology for low-cost, large-area, and low-power flexible electronics applications. Resistive memories based on metal oxide thin films have been extensively studied for application as next-generation nonvolatile memory devices. However, although the metal oxide-based resistive memories have several advantages, such as good scalability, low-power consumption, and fast switching speed, their application to large-area flexible substrates has been limited due to their material characteristics and necessity of a high-temperature fabrication process. As a promising nonvolatile memory technology for large-area flexible applications, we present a graphene oxide-based memory that can be easily fabricated using a room temperature spin-casting method on flexible substrates and has reliable memory performance in terms of retention and endurance. The microscopic origin of the bipolar resistive switching behaviour was elucidated and is attributed to rupture and formation of conducting filaments at the top amorphous interface layer formed between the graphene oxide film and the top Al metal electrode, via high-resolution transmission electron microscopy and in situ x-ray photoemission spectroscopy. This work provides an important step for developing understanding of the fundamental physics of bipolar resistive switching in graphene oxide films, for the application to future flexible electronics.

• 한국분말재료학회지
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• 제23권1호
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• pp.1-7
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• 2016

Cu-Mn compacts are fabricated by the pulsed current activated sintering method (PCAS) for sputtering target application. For fabricating the compacts, optimized sintering conditions such as the temperature, pulse ratio, pressure, and heating rate are controlled during the sintering process. The final sintering temperature and heating rate required to fabricate the target materials having high density are $700^{\circ}C$ and $80^{\circ}C/min$, respectively. The heating directly progresses up to $700^{\circ}C$ with a 3 min holding time. The sputtering target materials having high relative density of 100% are fabricated by employing a uniaxial pressure of 60 MPa and a sintering temperature of $700^{\circ}C$ without any significant change in the grain size. Also, the shrinkage displacement of the Cu-Mn target materials considerably increases with an increase in the pressure at sintering temperatures up to $700^{\circ}C$.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1993년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.2-2
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• 1993

The present status of the thennomechanica1 evaluation of functionally gradient materials(FGMs) for space plane application was reviewed, in which research activities and the cooperation of the national project team organized to study FGM science were demonstrated. The project team was divided into three working groups; de singing, processing and evaluation, each of which had their own tasks in the project cooperation. The testings details of the various thennomechanical tests for the FGM samples fabricated by the processing groups were described, along with their corresponding heating conditions of the real environments in the space plane application. For small-sized samples, laser beam heating test and burner heating test were well applied to study the heat shielding and heat resisting properties. Arc-heated wind tunnel test and high temperature!high velocity gas flow test were used for large-sized panel assemblies having cooling structures. The criteria for the evaluation of the heat shielding and heat resisting properties of the FGMs, as well as a crack activation mechanism in their differential temperature heating, were proposed on the basis of the observation in the burner heating test.

• 한국초전도ㆍ저온공학회논문지
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• 제14권4호
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• pp.32-35
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• 2012

A high-$T_c$ superconducting (HTS) DC application has advantages such as the ultimately lower loss, more compact dimensions, and large capacity compared to AC application. In order to optimize the insulation design of a HTS DC machines, it is important to understand the high voltage insulation and materials at cryogenic temperature. Polypropylene laminated paper (PPLP) has been widely used as an insulating material for HTS AC machines. However, the fundamental data under DC voltage have not been revealed satisfactorily until now. In this paper, we will discuss mainly on the breakdown and dielectric characteristics of PPLP in liquid nitrogen ($LN_2$). The polarity effects of DC and impulse voltage were studied by using the semi-rod to cylindrical electrode. The volume resistivity of PPLP in $LN_2$ was studied. Also, the space charge distribution at room temperature was studied. However, it is necessary to study this topic at cryogenic temperature in the near future.

• 한국토양비료학회지
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• 제14권4호
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• pp.201-209
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• 1982

'80년도(年度)는 수도재배기간중(水稻栽培期間中) 이상저온(異常低溫)이 계속(繼續)되었으며 냉해피해(冷害被害)가 컸으므로 냉해(冷害)의 양상(樣相)과 정도(程度) 및 영양흡수(營養吸收)와의 관계(關係)를 조사(調査)한 결과(結果)는 다음과 같았다. 1. '80년도(年度) 벼의 냉해(冷害)는 수도생육(水稻生育) 후기(後期)에 계속(繼續)된 저온(低溫) 및 일조부족(日照不足)과 더불어 감수분열기(減數分裂期)에 있었던 생식생장(生殖生長) 한계온도(限界溫度) 이하(以下)의 저온(低溫)에 크게 영향(影響)을 받았기 때문인 것으로 사료(思料)된다. 2. 삼요소중(三要素中) 질소무시용구(窒素無施用區)에서 냉해피해(冷害被害)가 적었으며 질소시용량(窒素施用量)이 많을수록 냉해(冷害)가 심(甚)한 경향(傾向)이었고 삼요소(三要素) 균형시비(均衡施肥)으로 냉해(冷害)가 경감(輕減)되었다. 3. 냉해(冷害)는 통일계품종(統一系品種)이 일반계품종(一般系品種)보다 심(甚)한 경향(傾向)이었고 냉해(冷害)는 불임(不稔), 영화퇴화(穎花退化), 추수불량(抽穗不良) 및 양분흡수(養分吸收) 억제등(抑制等)으로 나타났다. 4. 저온하(低溫下)에서는 질소시용량(窒素施用量)이 많을수록 식물체내(植物體內) 규산함량(珪酸含量)이 유의성(有意性)있게 감소(減少)되었다. 5. 냉해조건하(冷害條件下)에서의 통일계품종(統一系品種)의 질소비료(窒素肥料) 시용적량(施用適量)은 13.6kg/10a으로서 예년(例年)보다 약(約) 10kg/10a 적었으며 수량(收量)도 크게 감소(減少)되었고 감소율(減少率)은 통일계품종(統一系品種)이 일반계품종(一般系品種)보다 심(甚)하였다.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.124-128
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• 2018

Titanium doping is employed to enhance the structural strength of a high-Ni layered cathode material in lithium ion batteries during high temperature cycling. After Ti-doping, the external morphology remains similar, but the lattice parameters of the layered structure are slightly shifted toward larger values. With application of the prepared materials as cathodes in lithium-ion batteries, the initial capacities are similar but the cycling performance at $25^{\circ}C$ is enhanced by Ti-doping. During high temperature cycling at $60^{\circ}C$, furthermore, highly improved capacity retention is achieved with the Ti-doped material (95% of initial capacity at 50th cycles), while cycle fading is accelerated with the bare electrode. This enhancement is attributed to better retention of the compressive strength of the particles and retarded crack formation within the particles. In addition, impedance increase is reduced in the Ti-doped electrode, which is attributed to an improvement in the structural strength of the high-Ni cathode material with Ti-doping.

• 대한간호학회지
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• 제23권2호
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• pp.157-169
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• 1993

The most effective modality for cold application and the length of the application have not been determined despite many studies about the use of cold. A quasi-experimental study was conducted to examine the most effective modality among three methods of cold application, the most effective length of time for the application and the continuing effect after each type of cold application. Thirty adult patients admitted to medical and neurosurgical unit and with high fever (above 38.2 ℃) were assigned randomly to each of three cold ap-plication methods : (a) ice bag: (b) cold compress; and (c) tepid water sponge bath. Each method was applied to the whole anterior surface except the face and neck with the patient in the supine pos-ition. Rectal temperatures and skin temperatures (mid chest, upper arm, thigh and leg) were measured be-fore each application and every 10 minutes during ,each application for a period of 60 minutes. They were also measured every 10 minutes for 30 minutes after each cold application was finished. The experiments were carried out from Dec. 22. 1992 through Feb. 26, 1993. The data were analysed using means, ANCOVA Sheffe test and Pearson's Correlation Coefficient. The results of this study are as follows : 1. There were no significant differences among the three cold application methods in the reduction of body temperature, 2. Among the ice bag, cold compress and tepid water sponge bath groups, the ice bag proved to be the most effective method for lowering skin temperature while the cold compress was least effective. 3. Both rectal and skin temperature continued to decrease during the 60 minutes of cold application, but the hunting phenomena was not observed at any of the cold application sites. 4. There were no significant correlations between mean rectal and skin temperatures. 5. Skin temperatures according to the cold application sites decreased to a range of 3.46℃ to 5.20℃ (mid chest), a range of 4.48℃ 4.96℃ (upper arm), a range of 3.86℃ to 5.05℃ (thigh), and a range of 5.42℃ -7.12℃ (leg ). 6. In continuing effect after the cold applications were finished, rectal temperatures according to ice bag, cold compress and tepid sponge bath decreased to 0.29℃, 0.23℃ and 0.09℃ respectively, while the mean skin temperatures increased to 2.39℃ , 2.04℃ and 2.22℃ respectively. In this experiment the ice bag was the most effective modality for lowering skin temperature. when-ever cold is applied for systemic effect, the continuing effect of cold should be considered. The determination of the most effective length of time for cold application needs further study.

• 대한기계학회논문집B
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• 제33권5호
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• pp.299-310
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• 2009

Fuel cells are expected to be promising future power sources in both aspects of thermal efficiency and environmental friendliness. Accordingly, worldwide research and development efforts have been enormously increasing recently in various applications such as power plants, transportation and portable power sources. Among others, high temperature fuel cells, such as solid oxide fuel cells and molten carbonate fuel cells, are suitable for electric power plants. Moreover, their high operating temperature is quite appropriate to construct further advanced integrated systems. This paper reviews recent literatures on research and development of integrated power generation systems based on high temperature fuel cells. Research and development efforts are summarized in the area of fuel cell/ gas turbine hybrid systems, application of carbon capture technology to fuel cell systems, integration of coal gasification with fuel cells, and the use of alternative fuels.