• 제목/요약/키워드: cold air circulation

검색결과 46건 처리시간 0.026초

동해의 열적작용이 해수순환에 미칠 수 있는 영향에 관한 고찰 (On the Possible Role of Local Thermal Forcing on the Japan Sea Circulation)

  • 승영호;김구
    • 한국해양학회지
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    • 제24권1호
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    • pp.29-38
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    • 1989
  • 동해 해수순환의 특징은 대한해협으로부터 유입된 난수가 동한난류를 형성하여 한국연안을 따라 북상한 후 다시 외해로 분리되어 나간다는 것과 북쪽에서부터 연안을 따라 남하하는 북한한류가 형성하는 반시계 방향의 순환류가 동해 북부에 존재한다는 사실일 것이다. 본 논문에서는 이러한 사실을 설명하기 위하여 간단한 역학적 모델을 수립하였다. 동해 해수순환을 기본적으로 유입-유출 형태라 한 후 여기에 해양-대기 열 교환을 적용하였으며 해수혼합에 의한 열의 소멸, 마찰에 의한 운동량의 소멸도 고려하였다. 결과에 의하면, 상기의 순환특징은 열역학적 요인에 의하여 기인됨이 밝혀졌다. 또한, 열교환의 정도에 따라 여러가지 순환형태가 나타날 수 있음도 보였다.

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고온기 근권냉방방식에 따른 냉방효과와 토마토 생육 (Cooling Efficiency and Growth of Tomato as Affected by Root Zone Cooling Methods in Summer Season)

  • 이재한;권준국;권오근;최영하;박동금
    • 생물환경조절학회지
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    • 제11권2호
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    • pp.81-87
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    • 2002
  • 근권냉방 방식에 따른 냉방 효율과 토마토 생육 특성을 검토하고자 XL냉수순환, 라디에이타 냉풍, 패드냉풍 및 대조구를 처리한 결과는 다음과 같다. 근권부 냉방온도는 공급수온이 17.8$^{\circ}C$일 때 XL 냉수순환구는 18.$0^{\circ}C$ 라디에이타 냉풍구는 27.2$^{\circ}C$, 패드 냉풍구는 20.3$^{\circ}C$였다. 배지 깊이와 시간대별 평균온도는 XL냉수순환구 22.8~24.7$^{\circ}C$. 라디에이타 냉풍구 22.7~24.2$^{\circ}C$, 패드 냉풍구 20.5~23.2$^{\circ}C$, 대조구 25.9~29.6$^{\circ}C$를 나타내어 냉방처리구가 대조구에 비해 5~6$^{\circ}C$더 낮았다. 토마토의 생육에 있어 엽장. 엽폭은 대조구에 비해 컸으며, 생체중 및 건물중의 경우에서도 비슷한 경향이었다 근활력에 있어 대조구는 45.0ug/g에 비해 근권냉방 처리구는 58.5-62.8 ug/g으로 높았으나. 근권냉방 처리구간에는 큰 차이가 없었다.

Characteristics of Weather and Climate over the Okhotsk Sea

  • KIM Young Seup;HAN Young Ho;CHEONG Hyeong Bin;DASHKO Nina A.;PESTEREVA Nina M.;VARLAMOV Sergey M.
    • 한국수산과학회지
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    • 제30권6호
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    • pp.974-983
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    • 1997
  • The Okhotsk Sea is unique natural object with climatic peculiarities. The climate of the Okhotsk Sea results from the general distribution of solar radiation during a year, and the characteristics of the atmospheric circulation that varies through a year: In cold half year the main pressure formations are Siberian high and Aleutian low. Asian low centered on Afghanistan dominates over the Asian continent in summer. The North-Pacific sea surface is under effect of permanent North Pacific high. The changes in their position from year to year are very significant. The anticyclonic activity over the Far Eastern Seas is one of the main factors for the formation of weather anomalies over the adjacent territories. The analysis of summer weather characteristics over the coast of Okhotsk and East Sea using the data obtained from Hydrometeorological stations during $1949\~1990$ showed that, to a great extent, distribution of the air temperature depends on thermal state of the Okhotsk Sea and atmospheric circulation over it. We show some relations between weather characteristics and the intensity of atmospheric action center for the North Pacific high in summer when its ridge propagates to Okhotsk Sea. Correlation coefficients between air pressure over the Okhotsk Sea and air temperature for the coastal areas reach up to 0.7. Analysis of the spatial-temporal distribution of main meteorological values over the Okhotsk Sea such as air pressure, and air temperature are also performed.

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대구지역의 국지순환풍의 환기경로 및 대기오염수송에 관한 수치모의 (Numerical Simulation on the Wind Ventilation Lane and Air Pollutants Transport due to Local Circulation Winds in Daegu Districts)

  • 구현숙;김해동
    • 한국지구과학회지
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    • 제25권6호
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    • pp.418-427
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    • 2004
  • 최근 도시기후를 고려한 도시계획이 많은 나라에서 실용화되고 있다. 도시기후의 고려는 주로 도시의 바람 길 조성이라는 개념으로 구체화되고 있다. 도시의 바람 길 조성은 주로 하계에 도시지역의 열적 쾌적성을 개선하는 것을 목표로 한다. 아울러, 과학적 조사에 근거하여 도시의 단지계획을 합리적으로 함으로써 청정한 냉기류의 도심유입을 원활히 하여 도심의 대기오염을 저감하고자 하는 것도 목적으로 한다. 이 연구에서는, 수치실험을 통하여 전형적인 난후기일을 대상으로 대구지역의 국지순환풍이 지나는 바람의 길을 조사하였다. 그리고 이 바람에 의한 대기오염의 수송도 조사하였다. 수치실험에 사용한 모형은 RAMS(지역규모 대기모델)이다. 수치실험의 관심지역은 대구광역시 일대(약900$km^2$)이다. 수평규모는 약 30km이다. 수치실험은 일반풍이 약하고 쾌청한 일기조건을 갖는 늦봄의 기상조건 하에서 수행되었다. 수치실험의 결과 다음과 같은 3가지 결과를 얻었다: (1) 대구의 대표적 산지인 팔공산과 앞산에서 야간에 산정에서 복사냉각으로 생성된 국지풍이 지나는 길을 발견할 수 있었다. 그 바람은 대구의 동쪽 지역에서 중력류의 형태로 계곡을 따라서 흘러내렸다. (2) 평지에서는, 그 바람이 대구의 중심지를 지나 서쪽으로 흘러갔다. (3) 그 결과로, 대기오염물질은 야간에 국지풍에 의해 서쪽지역으로 수송되어졌다.

B/F형 냉장고 냉동실의 결빙원인에 관한 연구 (Fluid flow in the freezing compartment of the B/F Refrigerators)

  • 양수영;김윤규;박재성;정호윤;이연원
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 춘계학술대회논문집
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    • pp.530-533
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    • 2008
  • Refrigerators have some frost related problems in a freezing compartment. The frost formation in the refrigerator gives customers a bad impression concerning quality problems. Therefore, many engineers have been studying the optimum solution to avoid frost formation. But the problem of frost formation is very complex and hard to approach to the answer. The frost generation of a household refrigerator have been widely known that is closely related to the distribution of temperature inside the compartment. The distribution depends on the cold air circulation inside the refrigerator. So frost problem can be reduced and energy consumption efficiency also improved through optimization of air flow fields inside the freezing compartment. In this paper, numerical simulation has been carried out to check fluid flow. The variation of temperature at the walls was measured and quantitative analysis of frost generated from the freezing compartment was carried out. Through comparison between simulation and experiment, some correlation revealed.

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Numerical simulation of Hydrodynamics and water properties in the Yellow Sea. I. Climatological inter-annual variability

  • Kim, Chang-S.;Lim, Hak-Soo;Yoon, Jong-Joo;Chu, Peter-C.
    • Journal of the korean society of oceanography
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    • 제39권1호
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    • pp.72-95
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    • 2004
  • The Yellow Sea is characterized by relatively shallow water depth, varying range of tidal action and very complex coastal geometry such as islands, bays, peninsulas, tidal flats, shoals etc. The dynamic system is controlled by tides, regional winds, river discharge, and interaction with the Kuroshio. The circulation, water mass properties and their variability in the Yellow Sea are very complicated and still far from clear understanding. In this study, an effort to improve our understanding the dynamic feature of the Yellow Sea system was conducted using numerical simulation with the ROMS model, applying climatologic forcing such as winds, heat flux and fresh water precipitation. The inter-annual variability of general circulation and thermohaline structure throughout the year has been obtained, which has been compared with observational data sets. The simulated horizontal distribution and vertical cross-sectional structures of temperature and salinity show a good agreement with the observational data indicating significantly the water masses such as Yellow Sea Warm Water, Yellow Sea Bottom Cold Water, Changjiang River Diluted Water and other sporadically observed coastal waters around the Yellow Sea. The tidal effects on circulation and dynamic features such as coastal tidal fronts and coastal mixing are predominant in the Yellow Sea. Hence the tidal effects on those dynamic features are dealt in the accompanying paper (Kim et at., 2004). The ROMS model adopts curvilinear grid with horizontal resolution of 35 km and 20 vertical grid spacing confirming to relatively realistic bottom topography. The model was initialized with the LEVITUS climatologic data and forced by the monthly mean air-sea fluxes of momentum, heat and fresh water derived from COADS. On the open boundaries, climatological temperature and salinity are nudged every 20 days for data assimilation to stabilize the modeling implementation. This study demonstrates a Yellow Sea version of Atlantic Basin experiment conducted by Haidvogel et al. (2000) experiment that the ROMS simulates the dynamic variability of temperature, salinity, and velocity fields in the ocean. However the present study has been improved to deal with the large river system, open boundary nudging process and further with combination of the tidal forcing that is a significant feature in the Yellow Sea.

金元四大家의 外科疾患에 對한 硏究;(癰疽瘍瘡을 中心으로) (A Literature Study on Surgical Disease of the Four Famous Physicians in JinYuan Period)

  • 김희택;노석선
    • 한방안이비인후피부과학회지
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    • 제12권1호
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    • pp.179-214
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    • 1999
  • The result were as follows: 1. Yu Wan So(劉完素) regarded the cause of surgical disease as the heat(熱). He used the three method to drain(疏通), promoting pus drainage(托裏) and the balance between ying-energy(營氣) and wei-energy(衛氣). 2. Jang Jong Jeung(張從正) only refered to medicines without entire theory. 3. Lee Dong Won(李東垣) regarded the cause of surgical disease as the greasy diet(膏梁厚味), damp air(濕氣), wetness heat(濕熱). For each treatment he used the method of Yu Wan So's treatment and emphasized the balance between ying-energy(營氣) and wei-energy(衛氣), stomach energy(胃氣). 4. Ju Jin Heung(朱震亨) distinguished the cause of surgical disease from enternal(內), external(外) and channel(經). For each treatment he used the method to drain(疏通), promoting pus drainage(托裏) and the balance between ying-energy(營氣) and wei-energy(衛氣). The first stage used the clearing away heat and toxic materials(淸熱解毒) and the last stage used the invigoration and dispersion(補托). 5. Yu Wan So(劉完素) used to be very busy of Moschus(麝香), Alumen(白礬), Olibanum(乳香), Coptidis Rhizoma(黃連), Minium(黃丹) and Scutel1ariae Radix(黃芩) In classification of the medical action, great part of the medicine are activating blood circulation to dissipate blood stasis(活血祛瘀), clearing away heat and toxic materials( 淸熱解毒) and external application(外用). 6. Jang Jong Jeung(張從正) used to be very busy of Olibanum(乳香), Angelicae Gigantis Radix(當歸), Minium(黃丹), Myrrha(沒藥), Calomelas(輕粉), Rhei Radix Et Rhizoma(大黃) and Phellodendri Cortex(黃柏). In classification of the medical action, great part of the medicine arc activating blood circulation to dissipate blood stasis(活血祛瘀), clearing away heat and toxic materials(淸熱解毒) and diverged wind-cold evil(發散風寒). 7. Lee Dong Won(李東垣) used to be very busy of Forsythiae Fructus(連翹), Scuteliariae Radix(黃芩), Angelicae Gigantis Radix(當歸). Astragali Radix(황기), Glycyrrhizae Radix(炙甘草), Bupleuri Radix(紫胡), Phellodendri Cortcx(黃柏), and Coptidis Rhizoma(黃連). In classification of the medical action, great part of the medicine are activating blood circulation to dissipate blood stasis(活血祛瘀), regulating vital energy(理氣) and clearing away heat and toxic materials(淸熱解毒). 8. Ju Jin Heung(朱震亨) used to be very busy of Glycyrrhizae Radix(甘草), Astragali Radix(황기), Angelicae Gigantis Radix(當歸), Phellodendri Cortex(黃柏), Scutellariae Radix(黃芩), Ginseng Radix(人蔘), Qlibanum(乳香). In classification of the medical action, great part of the medicine are clearing away heat and toxic materiaIs(淸熱解毒), activating blood circulation to dissipate blood stasis(活血祛瘀) and diverged wind-cold evil(發散風寒).

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동양의 전통적 환경인식과 환경관 (Thre Traditional Perception and Viewpoint to Natural Environment in the Orient)

  • 오홍석
    • 한국환경교육학회지:환경교육
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    • 제3권1호
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    • pp.55-62
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    • 1992
  • In the orient, ancestor's perception to natural environment was related on the change of climate. Man had been a essence of the warm blood animal, which had suited in mild climate for living and acting. The weather of hot or cold was not only comfort in human life but influences negatively on human behavior. The most people of oriental was particularly interrelated to seasonal change of climate in earlier time. Because, there are elements such as temperature, humidity and wind in the category of climate, these elements differentiated seasonal change. The main methods of perception of natural environment were observed and classified. Although these methods were in the primitive stage, these coincided the tendency of modern science. For example, confucian was recognized the law of vertical air current that warm air rised and cold air sinked. And they could classify all elements nature based on the principles of 'Yin and Yang(陰陽論)' such as male and female, the sun and moon. shade and light etc. Thus results of the observation and the classification concerned with physical environment can be utilize a wisdom for progressive life of inhabitants. It was a origin of the education in natural environment. Commonness in the viewpoint of environment in the orient if recognized the law of circulation. Buddhism, originated in india, realized that all of phenomena in the world was changed slowly through the principles of cycle(輪廻說) such as male and female, the sun and moon, shade and light etc. Thus results of the observation and the classification concerned with physical environment can be utilized a wisdom for progressive life of inhabitants. It was a origin of the education in natural environment. Commonness in the viewpoint of environment in the orient if recognized the law of circulation. Buddhism, originated in India, realized that all of phenomena in the world was changed slowly through the principles of cycle(輪廻說). For example, whole of land is shifted from young stage to old stage as the life cycle of humanbeing. The theory of karma effects(葉報設) is so signify with the good result that good one's action is reap a sweet fruit. The most environmental problem in today must realized as a consequence of men's act. Then Taoism emphasized the pure nature without the artificiality. Because complexual environment was composed of several elements, It was maintained through the artificiality. Because complexual environment was composed of several elements, It was maintained through the interaction of cause and effects. The solution of environmental problem is maintenanced the harmony between cause and effects by a philosophical concept.

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Design Considerations on the Standby Cooling System for the integrity of the CNS-IPA

  • Choi, Jungwoon;Kim, Young-ki
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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    • pp.104-104
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    • 2015
  • Due to the demand of the cold neutron flux in the neutron science and beam utilization technology, the cold neutron source (CNS) has been constructed and operating in the nuclear research reactor all over the world. The majority of the heat load removal scheme in the CNS is two-phase thermosiphon using the liquid hydrogen as a moderator. The CNS moderates thermal neutrons through a cryogenic moderator, liquid hydrogen, into cold neutrons with the generation of the nuclear heat load. The liquid hydrogen in a moderator cell is evaporated for the removal of the generated heat load from the neutron moderation and flows upward into a heat exchanger, where the hydrogen gas is liquefied by the cryogenic helium gas supplied from a helium refrigeration system. The liquefied hydrogen flows down to the moderator cell. To keep the required liquid hydrogen stable in the moderator cell, the CNS consists of an in-pool assembly (IPA) connected with the hydrogen system to handle the required hydrogen gas, the vacuum system to create the thermal insulation, and the helium refrigeration system to provide the cooling capacity. If one of systems is running out of order, the operating research reactor shall be tripped because the integrity of the CNS-IPA is not secured under the full power operation of the reactor. To prevent unscheduled reactor shutdown during a long time because the research reactor has been operating with the multi-purposes, the introduction of the standby cooling system (STS) can be a solution. In this presentation, the design considerations are considered how to design the STS satisfied with the following objectives: (a) to keep the moderator cell less than 350 K during the full power operation of the reactor under loss of the vacuum, loss of the cooling power, loss of common electrical power, or loss of instrument air cases; (b) to circulate smoothly helium gas in the STS circulation loop; (c) to re-start-up the reactor within 1 hour after its trip to avoid the Xenon build-up because more than certain concentration of Xenon makes that the reactor cannot start-up again; (d) to minimize the possibility of the hydrogen-oxygen reaction in the hydrogen boundary.

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PIV 애니메이션에 의한 가정용 냉장고 냉동실의 냉기 순환 해석 (Analysis on Cold Air Circulation of a Domestic Refrigerator Freezer by PIV Animation)

  • 김진영;양창조;김정환;이영호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.686-691
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    • 2000
  • Animation technique from the PIV database is particularly emphasized to give macroscopic and Quantitative description of complex flow fields. As an example, an experimental study was carried out investigate the fundamental (low characteristics of the freezer with the domestic refrigerator. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. Image intensifier CCD camera to cope with illumination problem is arranged for the accurate PIV measurement of large flow field. As a results, continuous pictures of the spatial distribution of the instantaneous and time-mean velocity distribution are displayed in real-time sense.

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