• Title/Summary/Keyword: Heating source

검색결과 897건 처리시간 0.024초

비대칭 마그네트론 스퍼터링 방법에 의한 질화붕소막의 증착시 반응실내의 초기 수분이 입방정질화붕소 박막의 형성에 미치는 영향 (Effect of Moisture in a Vacuum Chamber on the Deposition of c-BN Thin Film using an Unbalanced Magnetron Sputtering Method)

  • 이은숙;박종극;이욱성;성태연;백영준
    • 한국세라믹학회지
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    • 제49권6호
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    • pp.620-624
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    • 2012
  • The role of moisture remaining inside the deposition chamber during the formation of the cubic boron nitride (c-BN) phase in BN film was investigated. BN films were deposited by an unbalanced magnetron sputtering (UBM) method. Single-crystal (001) Si wafers were used as substrates. A hexagonal boron nitride (h-BN) target was used as a sputter target which was connected to a 13.56 MHz radiofrequency electric power source at 400 W. The substrate was biased at -60 V using a 200 kHz high-frequency power supply. The deposition pressure was 0.27 Pa with a flow of Ar 18 sccm - $N_2$ 2 sccm mixed gas. The inside of the deposition chamber was maintained at a moisture level of 65% during the initial stage. The effects of the evacuation time, duration time of heating the substrate holder at $250^{\circ}C$ as well as the plasma treatment on the inside chamber wall on the formation of c-BN were studied. The effects of heating as well as the plasma treatment very effectively eliminated the moisture adsorbed on the chamber wall. A pre-deposition condition for the stable and repeatable deposition of c-BN is suggested.

시분할 방식 VVVF형 고주파 공진 인버터의 특성해석 (Characteristics analysis of time sharing method VVVF type high frequency resonant inverter)

  • 조규판;원재선;남승식;심광렬;배영호;김동희
    • 조명전기설비학회논문지
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    • 제16권3호
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    • pp.20-28
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    • 2002
  • 본 논문은 고주파 유도가열용 전원에 사용되는 VVVF기능을 내장한 시분할 방식 고주파 공진 인버터 회로를 제시하였다. 제안한 인버터는 종래의 전압형 하프 브릿지 직렬 공진 인버터를 단위 인버터로 하여 이 단위 인버터 3개를 입력전원에 병렬로 접속하여 스위칭 주파수의 3배의 출력 주파수를 얻을 수 있으며, 또, 인버터 내부에 VVVW 기능을 부여하여 출력전압.주파수를 제어 할 수 있고 ZVS 기능도 가지고 있다는 특징을 가지고 있다. 회로의 해석은 정규화 파라메타를 도입하여 범용성 있게 기술하였고, 인버터 특성을 스위칭 주파수, Phase-Shift의 위상차각($\phi$) 변화와 제 파라메타에 따라 특성평가를 행하였다. 실험을 통해 이론해석의 타당성을 검증하였으며, 향후 유도가열 웅용, DC-DC 컨버터 등의 전원 시스템에 웅용 가능성을 보여주고 있다.

검정콩의 발아물을 이용한 죽 제조의 최적화 조건에 관한 연구 (A Study of Optimum Conditions in Preparing Gruel with Black Bean Germ Sprout Source)

  • 이혜정;박희옥;이숙영
    • 한국식품영양학회지
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    • 제18권4호
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    • pp.287-294
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    • 2005
  • 콩의 발아는 이소플라본의 증가, 피트산과 섬유소의 감소 등의 변화를 가져오며, 이런 효과는 죽 자체의 소화 홉수를 촉진한다는 것 외에도 생리활성의 변화로 건강에 유익할 것으로 생각되어 발아 콩을 이용한 죽 제조의 최적 조건들을 찾고자 관능검사, 이화학검사와 물성검사를 하였다. 관능검사 결과에 따라 쌀을 주곡으로 하여 발아 콩을 $70\%$$30\%$첨가하여 볶아 즙을내는 방법의 호정화를 이용하였고, 최적 가열 시간과 가수량은 40분과 10배수의 죽제품이 기호도가 높은 것으로 평가되었다. 이화학 검사에서는 쌀 $100\%$인 죽과, 발아 콩 $30\%$ 첨가군과 비교한 결과 pH는 변화가 거의 없었으나, 발아 콩 $70\%$ 첨가군이 총당과 아밀로오스 함량은 높았고, 고형분과 퍼짐성은 낮았으며, Hunter's value도 L 값은 낮고, b 값은 높은 경향을 보였다. 따라서 검정 발아 콩을 이용한 죽의 제조 최적 조건을 $30\%$쌀, $70\%$ 발아 콩, 최적 가수량 9배, 최적 가열시간 40분으로 제시할 수 있는 것으로 본다.

Stem-leaves of Panax as a rich and sustainable source of less-polar ginsenosides: comparison of ginsenosides from Panax ginseng, American ginseng and Panax notoginseng prepared by heating and acid treatment

  • Zhang, Fengxiang;Tang, Shaojian;Zhao, Lei;Yang, Xiushi;Yao, Yang;Hou, Zhaohua;Xue, Peng
    • Journal of Ginseng Research
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    • 제45권1호
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    • pp.163-175
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    • 2021
  • Background: Ginsenosides, which have strong biological activities, can be divided into polar or less-polar ginsenosides. Methods: This study evaluated the phytochemical diversity of the saponins in Panax ginseng (PG) root, American ginseng (AG) root, and Panax notoginseng (NG) root; the stem-leaves from Panax ginseng (SPG) root, American ginseng (SAG) root, and Panax notoginseng (SNG) root as well as the saponins obtained following heating and acidification [transformed Panax ginseng (TPG), transformed American ginseng (TAG), transformed Panax notoginseng (TNG), transformed stem-leaves from Panax ginseng (TSPG), transformed stem-leaves from American ginseng (TSAG), and transformed stem-leaves from Panax notoginseng (TSNG)]. The diversity was determined through the simultaneous quantification of the 16 major ginsenosides. Results: The content of ginsenosides in NG was found to be higher than those in AG and PG, and the content in SPG was greater than those in SNG and SAG. After transformation, the contents of polar ginsenosides in the raw saponins decreased, and contents of less-polar compounds increased. TNG had the highest levels of ginsenosides, which is consistent with the transformation of ginseng root. The contents of saponins in the stem-leaves were higher than those in the roots. The transformation rate of SNG was higher than those of the other samples, and the loss ratios of total ginsenosides from NG (6%) and SNG (4%) were the lowest among the tested materials. In addition to the conversion temperature, time, and pH, the crude protein content also affects the conversion to rare saponins. The proteins in Panax notoginseng allowed the highest conversion rate. Conclusion: Thus, the industrial preparation of less-polar ginsenosides from SNG is more efficient and cheaper.

온실 내외부 공기열의 선택적 축열에 의한 히트펌프 난방성능 개선 (Improvement of Heat Pump Heating Performance by Selective Heat Storage Using Air Heat of Inside and Outside Greenhouse)

  • 권진경;김승희;전종길;강연구;장갑열
    • 생물환경조절학회지
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    • 제26권4호
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    • pp.353-360
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    • 2017
  • 본 연구에서는 장미 재배온실을 대상으로 온실 내부의 태양잉여열과 외부의 공기열을 선택적 열원으로 이용하여 온실난방용 온수를 생산할 수 있는 공기 대 물 히트펌프의 설계와 성능시험을 수행하였다. 태양잉여열 이용 축열운전과 외기열 이용 축열운전은 작물의 생육적온을 고려한 온실내부의 설정온도에 따라 자동전환 되도록 설계하였다. 제어반에 12개의 기준온도를 설정함으로써 축열운전 전환, 난방, 환기를 자동제어하며, 태양잉여열-외기열 선택적 축열운전에서 축열조의 온도는 축열능력과 난방부하에 대응하여 $35{\sim}52^{\circ}C$로 3단계 변온제어 하였다. 태양잉여열-외기열 선택적 축열에서 태양잉여열 이용 축열은 전체 시간의 23.1%, 외기열 이용 축열은 30.7%, 히트펌프 휴지시간은 46.2%를 차지하였으며, 난방성능계수는 태양잉여열 이용 축열 시 3.83, 외기열 이용 축열시 2.77, 전체 3.24로 평가되었다. 비교시험을 위해 축열조 온도를 $50{\sim}52^{\circ}C$로 항온제어 하는 조건에서 외기열 단독 이용 축열 시험을 수행하였으며 이때의 난방성능계수는 2.33으로 분석되었다. 결과적으로 공기 대 물 히트 펌프의 열원으로 온실내부 태양잉여열과 외부 공기열을 병용하고, 축열조 온도를 변온제어 한 결과 일반적인 외기열 이용 축열운전과 축열조 항온제어에 비해 난방성능 계수가 39% 향상됨을 확인하였다.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

단독주택용 태양열/지열 융복합시스템의 태양열 급탕성능 평가 (An Evaluation of the Solar Thermal Performance of the Solar/Geo Thermal Hybrid Hot Water System for a Detached House)

  • 백남춘;한승현;이왕제;신우철
    • 설비공학논문집
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    • 제27권11호
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    • pp.581-586
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    • 2015
  • In this study, an analysis was performed on the performance of the solar water heating system with geo-thermal heat pump for a detached house. This system has a flat plate solar collector ($8\;m^2$) and a 3 RT heat pump. The heat pump acts as an auxiliary heater of the solar water heating system. These systems were installed at four individual houses with the same area of $100\;m^2$. The monitoring results for one year are as follows. (1) The average daily operating time of the solar system appeared to be 313 minutes in spring (intermediate season), and 135 minutes and 76 minutes in winter and summer respectively. The reason for the short operating time in summer is the high storage temperature due to low water heating load. The high storage temperature is caused by a decrease in collecting efficiency as well as by overheating. (2) The geothermal heat pump as an auxiliary heater mainly operates on days of poor insolation during the winter season. (3) Despite controlling for total house area, hot water consumption varies greatly according to the number of people in the family, hot water usage habits, etc. (4) The yearly solar fraction was 69.8 to 91.5 percent, which exceeds the maximum value of 80% as recommended by ASHRAE. So the solar collector area of $8\;m^2$ appeared to be somewhat greater for the house with an area of $100\;m^2$. (5) The observed annual efficiency of solar systems was relatively low at 13.5 to 23.6%, which was analyzed to be due to the decrease in thermal efficiency and the overheating caused by a high solar fraction.

EnergyPlus를 이용한 건물 부위별 목질제품 적용에 따른 건축물 에너지 절감 기여도 평가 (Evaluation and Analysis of The Building Energy Saving Performance by Component of Wood Products Using EnergyPlus)

  • 서정기;위승환;김수민
    • Journal of the Korean Wood Science and Technology
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    • 제44권5호
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    • pp.655-663
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    • 2016
  • 최근, 전 세계적으로 온실 가스 증가에 따른 기후 변화에 대한 문제가 논의되고 있다. 그중, 건축물에서의 에너지 소비량은 전체 에너지 소비량의 40%까지 증가할 것으로 예상된다. 따라서 건축물에서의 에너지 소비량 절감에 대한 노력이 필요한 실정이다. 본 연구에서는, 건물에너지 절감에 효과적으로 기여하는 재료 중 하나인 목재를 이용하여, 목질 제품 구성에 따른 중부지방과 남부지방의 난방에너지 요구량에 대하여 시뮬레이션을 통해 분석하였다. 시뮬레이션 도구는 미국 에너지부(Department of Energy)가 BLAST와 DOE-2의 장점을 결합해 만든 동적 에너지 해석 엔진인 EnergyPlus를 이용하였다. EnergyPlus는 다양한 건물 및 HVAC 시스템 구성요소(Object)에 대한 입력항목(Field)을 가지고 있으며, 특히 건물, 공조시스템, 열원기기 사이의 피드백을 통해 통합된 동시계산을 수행하며, ASHRAE Standard 140-2007 표준에 따라 상용 프로그램 간의 비교를 통해 검증된 프로그램이다. 시뮬레이션을 위한 기상데이터는 EnergyPlus에서 제공하는 IWEC 인천 지역과 광주 지역의 epw 형식 기상데이터를 이용하였다. 대상 모델은 한국농어촌공사에서 제시한 2012년 농 어촌주택 표준설계도면 중 '농림-12-26-가' 유형을 이용하였으며 총 10개의 실로 구성되어 있다. 시뮬레이션 분석 결과, 중부지방과 남부지방 별 목질 제품의 적용 범위를 실내마감재, 실외마감재, 창호, 목구조로 단계적으로 변경해 지역에 따라 각각 16 Case의 시뮬레이션을 수행한 결과 실내외의 마감재로 목재를 사용한 것만으로도 에너지 성능이 향상된 것을 확인할 수 있었다.

태양에너지 연구 시험센타 설계 및 효율에 관한 연구 (Design & Performance of the Solar Energy Research & Test Center)

  • 오정무;이종호;최병완;조일식
    • 태양에너지
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    • 제2권2호
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    • pp.29-36
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    • 1982
  • The Solar Energy R&D Department of KIER under the auspice of the Korean government is pushing hard on the development of the passive solar technology with high priority for the expeditious widespread use of solar energy in Korea, since the past few years of experiences told us that the active solar technology is not yet ready for massive commercialization in Korea. KIER has completed the construction of the Solar Energy Research & Test Center in Seoul, which houses the major facilities for its all solar test programs. The Center was designed as a passive solar building with great emphasis on the energy conserving ideas. The Center is not only the largest passive building in Korea, but also the exhibit center for the effective demonstration of the passive heating and cooling technology to the Korean public. The Center was designed to satisfy the requirements based on the technical and economical criteria set by the KIER. Careful considerations, therefore, were given in depth in the following areas to meet the requirements. 1) Passive Heating Concepts The Center employed the combination of direct and indirect gain system. The shape of the Center is Balcomb House style, and it included a large built-in sunspace in front. A partition, consists of transparent and translucent glazings, separates the sunspace and the living space. Since most activities in the Center occur during the day time, direct utilization of the solar energy by the living spaces was emphasized with the limited energy storage capacity. 2) Passive Cooling Concepts(for Summer) Natural ventilation concept was utilized throughout the building. In the direct gain portion of the system, the front glazing can be openable during the cooling season. Natural convection scheme was also applied to the front sunspace for the Summer cooling. Reflective surfaces and curtains were utilized wherever needed. 3) Auxiliary Heat ing and Cooling System As an auxiliary cooling system, mechanical means(forced convection system) were adopted. Therefore forced air heating system was also used to match the duct work requirements of the auxiliary cool ing system. 4) Effect ive Insulation & Others These included the double glazed windows, the double entry doors, the night glazing insulation, the front glazing-frame insulation as well as the building skin insulation. All locally available construction materials were used, and natural lightings were provided as much as possible. The expected annual energy savings (compared to the non-insulated conventional building)of the Center was estimated to be about 80%, which accounts for both the energy conservation and the solar energy source. The Center is being instumented for the actual performance tests. The experimental results of the simplified tests are discussed in this paper.

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마이크로파를 이용한 초미세 균일 분산 BaTiO$_3$ 분말 제조 (Fabrication of Mono-Dispersed Ultrafine BaTiO$_3$ Powder Using Microwave)

  • 김현상;최광진;이상균;김영대;심상준;우경자;김경림;조영상
    • 한국세라믹학회지
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    • 제36권4호
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    • pp.343-353
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    • 1999
  • 2.45 GHz의 microwave가 수열 합성법으로 제조된 BaTiO3 분말의 특성에 미치는 영향을 조사하였다. 700W 출력으로 반응시켰을 때, microwave-autoclave system에서는 약 5분만에 BaTiO3 결정이 형성되기 시작하여, 10분 이상의 반응에서는 더 이상 결정성 증가는 관찰되지 않았다. Microwave-system의 경우에는 15분만에 결정이 형성되기 시작하여, 1시간정도의 반응으로 충분한 BaTiO3 분말을 얻을 수 있었다. Microwave를 이용한 균일가열의 영향으로 분말들은 균일하게 분산되어 있었고, 기존의 전기적인 가열 방법에서 나타나는 응집 현상이나 grain의 성장 등은 보이지 않았다. 제조된 분말의 크기는 보통 30~60 nm정도였는데, 졸 안의 Ba/Ti의 비가 분말의 크기를 결정하는데 중요한 역할을 하였다. 이는 여분의 바륨이 Ba(OH)2등과 같은 다른 상을 형성하여 BaTiO3 분말의 계면에 얇은 막을 형성하여 분말들의 응집 현상이나 grain의 성장을 억제하는 것으로 추정하였다. M1-crowave-autoclave 에서는 15분 정도의 반응만으로도 미량이지만 tetragonal-BaTiO3를 직접적으로 형성할 수 있었고, microwave-reflux에서는 25$0^{\circ}C$의 건조로써 미량의 tetragonal-BaTiO3를 얻을 수 있었다.

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