• 제목/요약/키워드: Field Environment

검색결과 8,398건 처리시간 0.038초

Effects of Supplementary Composts on Microbial Communities and Rice Productivity in Cold Water Paddy Fields

  • Xie, Kaizhi;Xu, Peizhi;Yang, Shaohai;Lu, Yusheng;Jiang, Ruiping;Gu, Wenjie;Li, Wenying;Sun, Lili
    • Journal of Microbiology and Biotechnology
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    • 제25권5호
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    • pp.569-578
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    • 2015
  • Cold water paddy field soils are relatively unproductive, but can be ameliorated by supplementing with inorganic fertilizer from animal waste-based composts. The yield of two rice cultivars was significantly raised by providing either chicken manure or cow dung-based compost. The application of these composts raised the soil pH as well as both the total nitrogen and ammonium nitrogen content, which improved the soil's fertility and raised its nitrification potential. The composts had a measurable effect on the abundance of nitrogencycling-related soil microbes, as measured by estimating the copy number of various bacterial and archaeal genes using quantitative real-time PCR. The abundance of ammonia oxidizing archaea and bacteria was markedly encouraged by the application of chicken manure-based compost. Supplementation with the composts helped promote the availability of soil nitrogen in the cold water paddy field, thereby improving the soil's productivity and increasing the yield of the rice crop.

Scanning Rayleigh Doppler Lidar for Wind Profiling Based on Non-polarized Beam Splitter Cube Optically Contacted FPI

  • Zheng, Jun;Sun, Dongsong;Chen, Tingdi;Zhao, Ruocan;Han, Yuli;Li, Zimu;Zhou, Anran;Zhang, Nannan
    • Current Optics and Photonics
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    • 제2권2호
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    • pp.195-202
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    • 2018
  • A Scanning Rayleigh Doppler lidar for wind profiling based on a non-polarized beam splitter cube optically contacted FPI is developed for wind measurement from high troposphere to low stratosphere in 5-35 km. Non-polarized beam splitter cube optically contacted to the FPI are used for a stable optical receiver. Zero Doppler shift correction is used to correct for laser or FPI frequency jitter and drift and the timing sequence is designed. Stability of the receiver for Doppler shift discrimination is validated by measuring the transmissions of FPI in different days and analyzed the response functions. The maximal relative wind deviation due to the stability of the optical receiver is about 4.1% and the standard deviation of wind velocity is 1.6% due to the stability. Wind measurement comparison experiments were carried out in Jiuquan ($39.741^{\circ}N$, $98.495^{\circ}E$), Gansu province of China in 2015, showing good agreement with radiosonde result data. Continuous wind field observation was performed from October 16th to November 12th and semi-continuous wind field of 19 nights are presented.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

  • Shen, Lian;Han, Yan;Cai, C.S.;Dong, Guochao;Zhang, Jianren;Hu, Peng
    • Wind and Structures
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    • 제24권1호
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    • pp.1-24
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    • 2017
  • Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

서해안 주요 고추 주산지에서 발생하는 총채벌레의 발생현황 (Monitoring Occurrence Status of Thrips Populations on Field-Cultivated Pepper at Major Cultivated Region in West Coast, Korea)

  • 서미혜;이성찬;양창열;윤정범;박정준
    • 환경생물
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    • 제36권4호
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    • pp.544-549
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    • 2018
  • 2017년과 2018년 노지고추 재배기간인 6~8월 간 전북 고창, 충남 청양, 충북 괴산지역 노지 고추 포장에서 총채벌레의 종류와 발생현황을 조사하였다. 시기별로 총채벌레를 채집하여 동정한 결과 꽃노랑총채벌레 (Frankliniella occidentalis), 대만총채벌레(F. intonsa), 파총채벌레(Thrips tabaci)의 발생이 확인되었다. 이들 3종 중 대만총채벌레가 시기별로 가장 발생 밀도가 높은 것으로 보아 우점종으로 보여진다. 총채벌레의 발생은 6월 하순부터 증가하기 시작하여 7월 중순에 밀도가 가장 높았다. 따라서, 노지고추에서 총채벌레 방제전략은 6월 상순부터 모니터링하여 밀도증가 이전에 적절한 방제방법을 동원하여야 할 것이다.

해양 정합장처리에서 매개변수 오정합과 바이어스 (Parameter Mismatches and its Biases in Ocean Matched Field Processing)

  • 박재은;김재수;신기철
    • 한국음향학회지
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    • 제24권2호
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    • pp.87-96
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    • 2005
  • 해양환경에서 정합장처리를 통해 음원위치를 추정할 경우 실측신호의 음장과 복제음장 사이에 각종 매개변수의 오정합이 발생하여 상관값의 저하와 함께 음원 위치추정 결과에 바이어스를 발생시킨다. 본 논문에서는 정합장처리를 이용한 음원 위치추정에서 해양환경 및 시스템 오정합 매개변수로 인한 바이어스와 상관값의 변화 그리고 민감도에 대해서 고찰하였다. 이를 위해 Pekeris 해양 도파관에서 수치실험을 수행하였으며, 그 결과 매개변수 오정합이 음원 위치에서의 바이어스와 상관값의 감소를 발생시켰다. 또한 매개변수 민감도 평가를 통해 배열의 경사와 수심, 해저면 수심과 해저층의 음속이 민감도가 높음을 확인 할 수 있었다.

다중경로환경에서 바닥고정형 선배열센서를 이용한 근거리표적의 위치추정기법 (Near-field Target Localization Using Bottom-mounted Linear Sensor Array in Multipath Environment)

  • 이수형;류창수;이균경
    • 한국음향학회지
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    • 제19권7호
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    • pp.7-14
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    • 2000
  • 본 논문에서는 바닥고정형 선배열센서를 이용하여 다중경로 신호를 이용한 근거리표적의 위치추정 알고리즘을 제안하였다. 다중경로를 통하여 근거리 표적의 신호가 센서에 도달하는 경우 각 신호의 원추각이 다르므로 신호들의 원추각과 시간차를 추정해서 3차원 표적의 위치를 추정할 수 있다. 원거리표적으로 가정하고 추정한 원추각과 신호들의 시간차에 대한 관계식을 유도하였으며 이들을 연립하여 표적의 위치를 추정하였다. 그러나 표적이 위치한 기하학적인 위치에 따라 신호들의 원추각이 거의 같아지는 지점이 존재한다. 이 경우 부가적인 1차원 탐색으로 표적의 위치를 추정하였다.

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Envi-met 모델을 이용한 도심지역 대기오염측정망 주변의 바람장 분석 (An Analysis of Wind Field around the Air Quality Monitoring Station in the Urban Area by Using the Envi-met Model)

  • 김민경;이화운;도우곤;정우식
    • 한국환경과학회지
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    • 제18권9호
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    • pp.941-952
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    • 2009
  • The urban microscale wind field around the air quality monitoring station was investigated in order to check how a building complex influences it. For this study as the high density areas Jwa-dong and Yeonsan-dong monitoring sites in Busan were chosen. As the direction of inflow which is perpendicular to the building of the monitoring station was expected to cause the considerable variation of the wind field, that direction was selected. The model Envi-met was used as the diagnostic numerical model for this study. It is suitable for this investigation because Envi-met has the microscale resolution. After simulating it, on the leeward side around a building complex the decrease of flow velocity and some of vortexes or circulation area were discovered. In addition, on the edge of the top at the building and at the back of the building the upward flow was developed. If the sampling hole of monitoring site were located in this upward flow, it would be under the influence of upward flow from the near street.