• 제목/요약/키워드: Midnight

검색결과 222건 처리시간 0.027초

자생 및 도입 켄터키 블루그래스 품종의 훼손비탈면 녹화 특성 (A Vegetation Characteristics of Native and Introduced Kentucky bluegrass Cultivars Seeded on Cut-Slop)

  • 정대영;심상렬;안병준
    • 한국환경복원기술학회지
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    • 제12권1호
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    • pp.82-91
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    • 2009
  • Research was initiated to investigate vegetation characteristics of native ('Pureundle' and 'Sewon') and introduced ('Brilliant' and 'Midnight') Kentucky bluegrass (KB, Poa pratensis L.) varieties by soil-seed applying system on a cut-slope in May 17, 2008. There were no statistic differences observed in soil hardness and soil moisture content while significant differences were observed in surface coverage rate, height and disease occurrence in native and introduced KB varieties. The introduced 'Brilliant' KB was highest in the surface coverage rate from the early period of seeding to August 11, 2008. The surface coverage rate of introduced varieties were high when compared to native varieties in their early growth stage. But native varieties reached to equal surface coverage rate with the introduced varieties when three months after seeding. The height of 'Pureundle' and 'Brilliant' KBs were high compared with Midnight and Sewon KBs. 'Pureundle' and 'Brilliant' KBs were damaged by disease whereas there were no disease occurrence in 'Midnight' and 'Sewon' KBs. Probably, the disease occurrence was close related with the height of KBs not with native and introduced KB varieties. These results indicate that the growth of KB on a cut-slope are statistically affected by varieties in early growth stage of this experiment but reach equal rate between native and introduced KB varieties in three months after seeding. This growth characteristics implies the huge potential of native KB varieties seeding for cut-slope vegetation. Considering that native KB varieties are adapted to a environment and have no risk of causing disturbance to the ecosystem compared to the introduced KB varieties, the use of them as native varieties for a cut-slope vegetation can be increased.

Statistical study on nightside geosynchronous magnetic field responses to interplanetary shocks

  • 박종선;김관혁;;이동훈;이은상;진호
    • 천문학회보
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    • 제37권2호
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    • pp.116.1-116.1
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    • 2012
  • When an interplanetary (IP) shock passes over the Earth's magnetosphere, the geosynchronous magnetic field strength near the noon is always enhanced, while the geosynchronous magnetic field near the midnight decreases or increases. In order to understand what determines the positive or negative magnetic field response at nightside geosynchronous orbit to sudden increases in the solar wind dynamic pressure, we have examined 120 IP shock-associated sudden commencements (SC) using magnetic field data from the GOES spacecraft near the midnight (MLT = 2200~0200) and found the following magnetic field perturbation characteristics. (1) There is a strong seasonal dependence of geosynchronous magnetic field perturbations during the passage of IP shocks. That is, the SC-associated geosynchronous magnetic field near the midnight increases (a positive response) in summer and decreases (a negative response) in winter. (2) These field perturbations are dominated by the radial magnetic field component rather than the north-south magnetic field component at nightside geosynchronous orbit. (3) The magnetic elevation angles corresponding to positive and negative responses decrease and increase, respectively. These field perturbation properties can be explained by the location of the cross-tail current enhancement during SC interval with respect to geosynchronous spacecraft position.

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화물자동차 보조 후미등화장치 설치에 따른 운전자 시인성 변화 (Legibility Change of Commercial Vehicles Equipped with the Rear Lighting System)

  • 조승진;이창희;금기정
    • 한국도로학회논문집
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    • 제15권5호
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    • pp.111-122
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    • 2013
  • PURPOSES : The purpose of this system (Rear Lighting System) is to provide illumination for the driver to operate the commercial vehicle safely after dark in highway, to increase the conspicuity of the vehicle, and especially be suggesting the finest observable improvement method, depending on color and pattern of rear lighting system of truck for midnight highway traffic. METHODS : Rear lightning system as an improving way for forward commercial vehicles lighting the securing sight from human factors and the surrounding environment in midnight driving. For this one, basic materials were collected from the data analysis about many types of problems, and filed investigation for establishing Driving Simulator. also taking statistic test to human volunteers after finding recognizable distance of them. RESULTS : As a result, color with the highest visuality is amber followed by green-red-blue as in order for all road types. Especially almost no difference is found between red and green, also when the light is turn off, recognizable distances is wide difference compared to turn on the light. One more thing about study per pattern, upper and entire lighting have similar recognizable distances, but under lighting shows short distance with difficulty securing sight from medians. And straight section shows similar recognizable distances. By finding visuality improvement method depending on color and pattern of supplement taillight, it is expected to suggest quantitative judgement standard for introducing regulation and improvement of supplement taillight. CONCLUSIONS : Night time vehicle conspicuity to the rear is provided by rear position lamps. this study is showed that the color of light ramp is not important to be safe driving, most important is to turn on the light, recognizable distances is big different compared to turn off the rear light, so when the drivng dark in highway, have to turn on the light for reducing risk.

Earthward Flow Bursts in the Magnetotail Driven by Solar Wind Pressure Impulse

  • Kim, Khan-Hyuk;Kwak, Young-Sil;Lee, Jae-Jin;Hwang, Jung-A
    • Journal of Astronomy and Space Sciences
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    • 제25권4호
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    • pp.375-382
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    • 2008
  • On August 31, 2001, ${\sim}$ 1705 - 1718 UT, Cluster was located near the midnight magnetotail, GSE (x, y, z) ${\sim}$ (-19, - 2,2) RE, and observed fast earthward flow bursts in the vicinity of the neutral sheet. They occurred while the tail magnetic field suddenly increased. Using simultaneous measurements in the solar wind, at geosynchronous orbit, and on the ground, it is confirmed that tail magnetic field enhancement is due to an increased solar wind pressure. In the neutral sheet region, strongly enhanced earthward flow bursts perpendicular to the local magnetic field $(V_{{\perp}x})$ were observed. Auroral brightenings localized in the pre-midnight sector (${\sim}$ 2200 - 2400 MLT) occurred during the interval of the $V_{{\perp}x}$ enhancements. The $V_{{\perp}x}$ bursts started ${\sim}$ 2 minutes before the onset of auroral brightenings. Our observations suggest that the earthward flow bursts are associated with tail reconnection directly driven by a solar wind pressure impulse and that $V_{{\perp}x}$ caused localized auroral brightenings.

축냉 시스템을 적용한 쇼케이스 운전에 대한 실험적 연구 (Experimental Study of Showcase Using Cold Storage System)

  • 이은지;이동원;김용찬
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 하계학술발표대회 논문집
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    • pp.1111-1116
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    • 2008
  • The purpose of this study is to maintain high efficiency and reasonable use of cold-heat storage systems operated the showcase. An experimental study is carried out to manufacture the showcase system in a laboratory. Comparing the result at general operation condition with that at the new condition using ice storage system, this study showed the effects of the refrigerant sub-cooling, and with using inverter. At the condition using ice storage system, the ice making process was operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, hence the running time of the compressor was effectively decreased. In other words, this study showed that power consumption during daytime can be transferred to the midnight for making use of the refrigerant sub-cooling.

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쇼케이스 운전상태를 고려한 축냉시스템 적용타당성 연구 (A study on the Cold-heat Storage System for Operation Status Monitoring of Showcase)

  • 이은지;이동원
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 하계학술발표대회 논문집
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    • pp.1261-1266
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    • 2008
  • Experimental study was performed to understand the operations of a showcase working in a discount store. Temperatures of evaporation, condenser were measured and also electric power consumption of compressor were measured. The purpose of this study is to application use of cold-heat storage systems operated the showcase. At the condition using ice storage system, the ice making process was operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, hence the running time of the compressor was effectively decreased. In other words, this study showed that power consumption during daytime can be transferred to the midnight for making use of the refrigerant sub-cooling. So the operating characteristics of the showcase system under various working conditions were analyzed and discussed.

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한국 동해남부해역 앨퉁이 난.자어의 연직분포 (Vertical Distribution of Eggs and Larvae of Maurolicus muelleri in the Southeastern Waters of Korea)

  • 김진영;강영실
    • 한국어류학회지
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    • 제7권1호
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    • pp.64-70
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    • 1995
  • 1985~1986년 6~8월에 한국 동해남부해역의 0~30m, 30~50m, 50~100m 수층에서 개폐식 채집망을 수직인망하여 채집된 앨퉁이(Maurolicus muelleir)난과 자어 및 동물부유생물의 연직분포특성을 분석하였다. 그 결과, 앨퉁이 난과 동물 부유생물은 8월에 높은 밀도를 보였다. 또한 $10{\sim}15^{\circ}C$를 중심으로 하는 수온약층주변에서 분포밀도가 높았으며, 1985년에는 50m 이천에서, 1976년에는 30~100m 수층에서 높은 밀도를 나타내었다. 한편, 앨퉁이 난의 발생 단계별 분포밀도를 보면 난할기에는 50~100m 수층의 분포밀도가 가장 높았으나 배체형성이 진행되면서 30~50m 수층의 분포밀도가 높아지는 경향을 보였다. 채집시각별 분포수층과 각 발생 단계의 분포비율을 분석한 결과, 자정에는 30~50m와 50~100m 수층에서 거의 같은 비율로 분포하였으나 새벽이후 석양까지 30~50m 수층의 분포비율이 높아졌으며, 자정 전후에 난할기 난의 비율이 가장 높았다. 따라서 앨퉁이는 자정전후에 50~100m 수층에서 산란하여 발생이 진행되면서 30~50m 수층으로 부상한다고 추정된다.

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