• 제목/요약/키워드: Altitude of the sun

검색결과 243건 처리시간 0.022초

Ecological Characteristics of Natural Habits of Deutzia paniculata, a Rare and Endemic Woody Species in Korea

  • Park, Jin-Sun;An, Jong-Bin;Yun, Ho-Geun;Yi, Myung-Hoon;Park, Wan-Geun;Shin, Hyun-Tak;Hong, Yong-sik;Lee, Kyeong-Cheol;Shim, Yun-Jin;Sung, Jung-Won
    • Journal of Forest and Environmental Science
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    • 제37권3호
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    • pp.206-216
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    • 2021
  • Deutzia paniculata Nakai, a rare and endemic plant, has limited distribution throughout the North and South Gyeongsang provinces of South Korea. The D. paniculata community grows mostly on the stony slopes of forests, valley edges, and rock layers at 250-960 m in altitude, where deciduous trees are dominant and high humidity is maintained. Correlation analysis of vegetation and environmental factors found that the Walter's dogwood-mulberry community was correlated with soil acidity (pH). Whilst the queritron community had correlations with distance from the valley, rock rate and slope. The natural habitat of the Palgongsan Mountain in Daegu is known to have high genetic diversity, had eight D. paniculata individuals recorded from 2014 to 2018, and 12 individuals recorded in 2020 (new individuals due to a newly created space within the herbaceous layer caused by grass mowing works), it is therefore unlikely that the community would perish unless there was an artificial disturbance. To conserve the natural habitats of D. paniculata, oppression by Sasa borealis, damage, increase in crown density of the upper layer, overexploitation, and absence of seedlings should be carefully investigated. In addition, response measures should also be established and the impact on seed fullness and the reproductive characteristics of D. paniculata recorded. To restore declined genetic diversity, individuals from high genetic diversity regions, such as Palgongsan Mountain, should be artificially transplanted.

정밀 GPS 위성궤도 결정 및 오차 특성 분석 (Precision GPS Orbit Determination and Analysis of Error Characteristics)

  • 배태석
    • 한국측량학회지
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    • 제27권4호
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    • pp.437-444
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    • 2009
  • 동역학적 방법을 이용한 GPS(Global Positioning System) 위성궤도 결정을 위해 양방향 적분이 가능한 multi-step 방식의 수치적분기를 개발하였으며, 이는 GPS 위성 고도에서 마이크로미터 수준의 정확도를 보였다. 가속도 모델링에서 달, 태양 이외의 천체에 의한 인력은 매우 작으므로 태양복사압에서 경험적 모델로 대체하였다. 위성궤도 미지수는 수치적분된 위성궤도와 IGS(International GNSS Service) 정밀궤도를 이용하여 최소제곱방법으로 결정했다. 이를 위해서는 수치적분기에서 가속도와 함께 미지수에 대한 편미분값을 동시에 적분해야 한다. 추정된 위성궤도 미지수를 이용하여 계산한 잔차의 RMS(Root Mean Squares error)로 부터 위성궤도의 정확도를 검증했다. 2009년 3월 한달의 평균적인 궤도오차 RMS는 5.2mm 였으며, 궤도오차의 절대적인 크기는 위성체의 종류 및 위성진행방향기준 좌표계 상에서 특별히 편향된 형태를 보이지는 않는 것으로 나타났다. 본 연구에서 적용한 태양복사압 모델은 상수항 및 궤도당 1주기에 대한 변화만을 포함하고 있으므로, 궤도당 2주기에 해당하는 궤도오차 양상을 크게 보이고 있으며 이에 대한 추가적인 연구가 필요할 것으로 판단된다.

이중 블라인드 광파이프 주광 조명시스템 효율 및 조명에너지 절감량 평가 연구 (Evaluation Study of a Double Blind Light Pipe Daylighting System Efficiency and an Illumination Energy Reduction)

  • 강은철;유성연;이의준
    • 한국태양에너지학회 논문집
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    • 제33권1호
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    • pp.89-95
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    • 2013
  • A DBLP(Double blind light pipe) daylight system can be installed at a building exterior wall or roof to replace artificial light during the day time. This system was consisted of a double blind light collector, a mirror duct type light transformer and a prism light pipe distributor. The double blinds were used to track the sun's altitude and azimuth movements to collect the sunlight throughout the day. The sunlight collected by the light collector was reflected on the first mirror and the second mirror and sent to the light pipe through the light transformer. The transformer was designed to deliver the sunlight into the light pipe efficiently. The light distributor plays a role in diffusing the sunlight coming in through the light collector to be used for indoor lighting. In this paper, a DBLP system has been designed, installed and tested at a KIER daylighting twin test cell. The DBLP daylighting system was applied to the experimental test cell which has an indoor area of 2.0 m wide ${\times}$ 2.4 m height ${\times}$ 3.8 m length. The experiment was conducted from January 30 to February 27, 2012, under clear skies and partially cloudy skies. Data was collected from 10:00 am to 16:00 pm every 2 minute and the average was calculated for every 30 minute of the data collection to obtain the system efficiency. The results indicated that the DBLP system efficiency was evaluated as 11.67%. The DBLP system indoor illumination energy reduction was predicted as 0.822 kWh/day. This could replace 4 sets of a 32W fluorescent lamp operating 6.4 hours per a day.

In vitro Stimulation of NK Cells and Lymphocytes Using an Extract Prepared from Mycelial Culture of Ophiocordyceps sinensis

  • Sun-Hee Jang;Jisang Park;Seung-Hwan Jang;Soo-Wan Chae;Su-Jin Jung;Byung-Ok So;Ki-Chan Ha;Hong-Sig Sin;Yong-Suk Jang
    • IMMUNE NETWORK
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    • 제16권2호
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    • pp.140-145
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    • 2016
  • Ophiocordyceps sinensis is a natural fungus that has been valued as a health food and used in traditional Chinese medicine for centuries. The fungus is parasitic and colonizes insect larva. Naturally occurring O. sinensis thrives at high altitude in cold and grassy alpine meadows on the Himalayan mountain ranges. Wild Ophiocordyceps is becoming increasingly rare in its natural habitat, and its price limits its use in clinical practice. Therefore, the development of a standardized alternative is a great focus of research to allow the use of Ophiocordyceps as a medicine. To develop an alternative for wild Ophiocordyceps, a refined standardized extract, CBG-CS-2, was produced by artificial fermentation and extraction of the mycelial strain Paecilomyces hepiali CBG-CS-1, which originated from wild O. sinensis. In this study, we analyzed the in vitro immune-modulating effect of CBG-CS-2 on natural killer cells and B and T lymphocytes. CBG-CS-2 stimulated splenocyte proliferation and enhanced Th1-type cytokine expression in the mouse splenocytes. Importantly, in vitro CBG-CS-2 treatment enhanced the killing activity of the NK-92MI natural killer cell line. These results indicate that the mycelial culture extract prepared from Ophiocordyceps exhibits immune-modulating activity, as was observed in vivo and this suggests its possible use in the treatment of diseases caused by abnormal immune function.

FORMOSAT-2'S EFFECTIVENESS TO TAIWAN'S PUBLIC EDUCATION

  • Chern, Jeng-Shing;Wu, Lance;Liou, Yuei-An
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.959-962
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    • 2006
  • Public education is undoubtedly a very important aspect for a country to develop space program. People have the rights to understand how the tax they paid is being used. This paper addresses the effectiveness of FORMOSAT-2 on public education in Taiwan. As the first remote sensing satellite of the National Space Organization (NSPO) of Taiwan, FORMOSAT-2 is a small satellite of 746 kg mass for two remote sensing missions: Earth and upward lightning observations. The mission orbit is sun-synchronous of 888 km altitude for exactly 14 revolutions per day. For earth observation, the payload is an advanced high resolution remote sensing instrument (RSI) with ground sampling distance (GSD) 2 m in panchromatic (PAN) band and 8 m in four multi-spectral (MS) bands. For upward lightning observation, the payload is an imager of sprites and upper atmospheric lightning (ISUAL). After more than two years of Earth observation started in June 2004, the effectiveness of FORMOSAT-2 images on public education in Taiwan is very promised. Five domestic universities and one private company in Taiwan have signed contracts respectively with NSPO to take the roles of satellite image investigator and distributor. A private company has signed contract with NSPO to generate and provide URMAP (= your map) in its website for general public applications by using FORMOSAT-2 images. The Newtonkids Book Company used FORMOSAT-2 images to publish a kind of calendar for children education purpose. Besides, a science team in National Cheng Kung University (NCKU) is doing the research work on the 3820 (up to 30 June 2006) transient luminous events (TLEs) observed by FORMOSAT-2.

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유량평형시험을 통한 환경제어계통 설계 검증 (Design Verification of Environmental Control System by Flow Balance Test)

  • 박동명;정용인;문우용;박성순
    • 한국항공우주학회지
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    • 제40권7호
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    • pp.608-615
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    • 2012
  • 본 연구는 무인항공기의 항전베이와 환경제어계통이 가지고 있는 시스템 특성을 분석하여 항전장비에 공급되는 적정 유량을 예측하였다. 예측된 결과를 바탕으로, 각 토출구에서 토출되는 유량과 유량 분포를 분석하여 환경제어계통에 대한 성능을 분석함과 동시에 항전베이에 대한 열해석을 수행하여 유량 분포의 적절성을 입증하였다. 분석된 결과에 대한 타당성을 검증하기 위해 실제 환경제어계통을 이용하여 유량평형 시험장비를 구축하고, 유량평형시험을 수행하였으며, 항전장비의 시스템 요구조건에 부합되는 유량을 최종 도출하였다. 또한, 중고도 운용환경에서 시스템 요구조건의 충족여부를 검증하고 환경제어계통에 대한 열교환 성능을 입증하였다.

교실의 주광 조명환경과 철판의 눈부심 현상에 관한 연구 (A Study on the Daylight Illumination Environment of a Classroom and a Glare Phenomenon on the Blackboard)

  • 임윤빈;장우진
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 1996년도 추계학술발표회논문집
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    • pp.42-48
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    • 1996
  • 계절별로 태양의 위치와 강렬한 광선에 의한 칠판의 눈부심 현상은 교실내 조도가 충분한데도 불구하고 복도쪽과 창쪽의 앞줄 학생에게는 많은 시각 장애를 주어 판서를 읽을 수 없는 상태에까지 이르고 있으며 흐린날과 비오는날은 교실 조도가 매우 낮아 수업을 하기에 매우 어려운 상태에 이르고 있다. 학교에서는 자리배치를 획일적으로 키순으로 정하고 있는데 거리에 따른 시력인지도가 차이가 나서 뒷자리 학생은 시책이 1.0인데도 불구하고 1.0이하로 시력이 저하되고 창쪽과 복도쪽의 앞줄 학생은 눈부심 현상에 따른 판서의 인지도(시력)가 매우 낮아 학습효과가 반감되고 학습의욕을 떨어뜨리는 요인이 되고 있다. 따라서 학교에서는 학교 건물의 구조 변경과 칠판의 위치변경 및 재질향상을 시키며 칠판에 대한 국부적인 조명시설을 해주어야 하며 학생들의 자리를 획일적으로 키순으로 배치할 것이 아니라 일정한 주기로 바꿔 주어야 할 것으로 사료된다.

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GIS 음영기복과 렌더링의 비교에 의한 수치지형모형의 표현 분석 (Analysis of Digital Terrain Model Display by Comparison of GIS Shaded Relief and Rendering)

  • 이형석
    • 한국지리정보학회지
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    • 제9권1호
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    • pp.127-136
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    • 2006
  • 수치지형모형을 시각적으로 분석하는데 있어 음영기복을 사용하고 있지만 지형의 음영 표현만을 생각하는 경우가 있어 정확한 그림자 범위를 확인하지 않고 있다. 본 연구는 GIS의 지형 표현에 사용되는 음영기복 기능을 렌더링과 비교하여 지형의 그림자 특성을 파악함으로써 각각 나타나는 수치지형모형상의 표현 차이를 분석하였다. 도로가 있는 지형으로 실험 대상지역을 선정하여 불규칙삼각망의 수치지형모형을 생성한 후 09시와 15시의 시간대별 태양의 방위각 및 고도에 따른 음영기복과 렌더링 기법을 적용하였다. 그 결과 음영기복은 태양의 광선을 받는 지형지물의 뒷부분만 어두운 상태로 나타났고, 렌더링을 통하여 투영된 그림자가 생성됨을 알 수 있었다. 이 상호 비교를 통해 음영기복을 이해할 수 있는 자료로 제시할 수 있으며, 렌더링 기법은 지형지물의 일조 분석 등에 효과적으로 사용될 수 있을 것으로 기대된다.

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Far-ultraviolet Observations of the Comet C/2001 Q4 (NEAT)

  • Lim, Yeo-Myeong;Min, Kyoung-Wook;Seon, K.I.;Han, W.;Edelstein, J.
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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    • pp.20.1-20.1
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    • 2011
  • We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual-channel imaging spectrograph (S channel 900-1150 ${\AA}$, L channel 1350-1750 ${\AA}$, ${\lambda}/{\Box}{\lambda}$ ~ 550) with large image fields of view (S: $4^{\circ}.0{\times}4'.6$, L: $7^{\circ}.5{\times}4'.3$, angular resolution 5'-10') optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) was observed with a scanning survey mode when it was located around the perihelion between 8 and 15 May 2004. Several important emission lines were detected including S I (1425, 1474 ${\AA}$), C I (1561, 1657 ${\AA}$) and several emission lines of CO $A1{\cap}-X1{\sum}+$ system in the L channel. We estimated QCO = ($2.58\;{\pm}\;0.64)\;{\times}\;1028$ s-1 from the production rate of CO 1510 ${\AA}$. We obtained L-channel image which have map size of $5^{\circ}{\times}5^{\circ}$. The image was constructed for the wavelength band of L-channel (1350-1750 ${\AA}$).We also obtained radial profile of S I, C I, CO with line fitting from central coma.

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추적식 수상 태양광발전 구조물의 시공 및 안전성 평가 (Installation and Safety Evaluation of Tracking-type Floating PV Generation Structure)

  • 장민준;김선희;이영근;우상벽;윤순종
    • 복합신소재구조학회 논문집
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    • 제5권1호
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    • pp.1-8
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    • 2014
  • Pultruded glass fiber reinforced polymeric plastic (PFRP) and FRP member manufactured by sheet molding compound (SMC) have superior mechanical and physical properties compared with those of conventional structural materials. Since FRP has an excellent corrosion-resistance and high specific strength and stiffness, the FRP material may be highly appreciated for the development of floating-type photovoltaic (PV) power generation system. In this paper, advanced floating PV generation system made of PFRP and SMC is designed. In the design, it includes tracking solar altitude by tilting photovoltaic arrays and tracking solar azimuth by spinning structures. Moreover, the results of the finite element analysis (FEA) are presented to confirm stability of entire structure under the external loads. Additionally, installation procedure and mooring systems in the Hap-Cheon Dam are discussed and the measurement of strain under the actual circumstances is conducted for assuring stability of actually installed structures. Finally, by comparison with allowable stress, appropriate safety of structure is confirmed to operate the system.