• 한국진공학회:학술대회논문집
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• 한국진공학회 2005년도 제29회 학술발표회 초록집
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• pp.78-78
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• 2005

• 한국초지조사료학회지
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• 제22권1호
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• pp.23-30
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• 2002

본 연구는 제주지역에서 양마의 주당 본수 1(16,000주/10a), 2(34,000주/10a), 3(48,000주y10a), 4(64,000주/10a), 및 5본(80,000주/10a)에 따른 생육특성, 사료수량성 및 사료가치를 검토하고, 가축 조사료로 이용하기 위하여 2001년 4월 13일부터 10월 8일까지 수행하였으며, 그 결과를 요약하면 다음과 같다. 초장은 주당 1본에서 176cm였으나 주당 2본에서 185cm로 길어졌으나 그 이상 주당 본수가 많아짐에 따라 점차적으로 작아져서 5본에서는 166cm로 작아졌다. 생초, 건물, 단백질 및 TDN수량은 주당 2본에서 각각 114.6MT/ha, 17.3MT/ha, 2.33MT/ha, 9.21MT/ha로 가장 증수되었으나 그 이상과 그 이하의 본수에서는 점차적으로 감소되었고, 주당 5본에서는 생초수량 44.6MT/ha, 건물 수량 4.9MT/ha 단백질 수량 0.75MT/ha, TDN 수량은 2.83MT/ha로 감수되었다. 주당 본수가 1본에서 5본으로 많아짐에 따라 조단백질 함량 13.1%에서 15.4%로, 조지방 함량 3%에서 3.7%, 가용무질소물 20.1% 에서 23.2%로, TDN 함량은 41.1%에서 45.4%로 증가되었으나 조섬유와 조회분 함량은 각각 41.2%에서 34.9%로, 9.4%에서 8.2%로 감소되었다.

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.169-182
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• 2015

When simulating the dynamic behaviour of a hydro power plant, it is essential to have a good representation of the turbine behaviour. The pressure transients in the system occurs because the flow changes, which the turbine defines. The flow through the turbine is a function of the pressure, the speed of rotation and the wicket gate opening and is, most often described in a performance diagram or Hill diagram. In the Hill diagram, the efficiency is drawn like contour lines, hence the name. A turbines Hill diagram is obtained by performance tests on scaled model in a laboratory. However, system dynamic simulations have to be performed in the early stage of a project, before the turbine manufacturer has been chosen and the Hill diagram is known. Therefore one have to rely on diagrams for a turbine with similar speed number. The Hill diagram is drawn through measured points, so for using the diagram in a simulation program, one have to iterate in the diagram based on curve fitting of the measured points. This paper describes an alternative method. By means of the Euler turbine equation, it is possible to set up two differential equations which represents the turbine performance with good enough accuracy for the dynamic simulations. The only input is the turbine's main geometry, the runner blade in- and outlet angle and the guide vane angle at best efficiency point of operation (BEP). In the paper, simulated turbine characteristics for a high head Francis turbine, and for a reversible pump turbine are compared with laboratory measured characteristics.

• 한국대기환경학회지
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• 제14권3호
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• pp.219-228
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• 1998

In the present investigation, a numerical model developed for the prediction of the wind flow over complex terrain is validated by comparing with the field experiments. For the solution of the Reynolds - Averaged Clavier- stokes equations which are the governing equations of the microscale atmospheric flow, the model is constructed based on the finite-volume formulation and the SIMPLEC pressure-correction algorithm for the hydrodynamic computation. The boundary- fitted coordinate system is employed for the detailed depiction of topography. The boundary conditions and the modified turbulence constants suitable for an atmospheric boundary- layer are applied together with the k- s turbulence model. The full- scale experiments of Cooper's Ridge, Kettles Hill and Askervein Hill are chosen as the validation cases . Comparisons of the mean flow field between the field measurements and the predicted results show good agreement. In the simulation of the wind flow over Askervein Hill , the numerical model predicts the three dimensional flow separation in the downslope of the hill including the blockage effect due to neighboring hills . Such a flow behavior has not been simulated by the theoretical predictions. Therefore, the present model may offer the most accurate prediction of flow behavior in the leeside of the hill among the existing theoretical and numerical predictions.

• 농촌계획
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• 제17권3호
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• pp.15-25
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• 2011

This paper is to contribute for management and restoration as a basic study of vegetation structure in Aemirang Hill, Nakdongjeongmaek. To verify the characteristics of vegetation structure, we set up 25 plots($100m^2$). The result of community analysis was used by TWINSPAN classification. The communities were classified 7 types i.e. Quercus variabilis community, Quercus mongolica community, Pinus densiflora community, Pinus densiflora-Quercus mongolica community, Q. mongolica-Quercus variabilis community, Quercus mongolica-Betula davurica community, Larix leptolepis community. Pinus densiflora community and Pinus densiflora-Quercus mongolica community are progressively transforming a Quercus mongolica community that is called Pinus densiflora next succession stage. Whereas the communities that has dominant Quercus variabilis and Quercus mongolica did not appear a next generation succession tree such as Carpinus laxiflora, Carpinus cordata in the under story and shrub layer. Therefore, Aemirang Hill's ecological succession was to maintain the status condition. Aemirang Hill's diversity index is 0.5738 to 0.8906. It were analyzed that diversity index was lower than other places.

• 대한토목학회논문집
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• 제31권3B호
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• pp.233-242
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• 2011

본 연구에서는 하천유역에서 사면과 하천망의 방향적 특성을 von Mises 분포를 이용하여 정량화하고, 그 둘 사이의 관계를 살펴보았다. 궁극적으로는 사면과 하천의 방향성이 일정한 관계를 갖는지, 이러한 특성이 강우-유출 모형에 고려될 수 있는지에 대해 살펴보았다. 대상유역인 내성천 유역에 적용한 결과, von Mises 분포는 하천망의 방향적 특성을 적절히 표현할 수 있음을 확인하였다. 또한 하천망의 방향성은 사면의 방향성과 뚜렷한 관계를 가지며, 고차 하천일수록 뚜렷한 mode 특성을 나타냄을 확인하였다. 본 연구의 결과는 하천과 사면의 방향성에 따른 유출응답 특성을 정량적으로 파악하는데 이용될 수 있을 것이다.

• Wind and Structures
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• 제19권2호
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• pp.219-232
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• 2014

The characteristics of turbulent boundary layers over hilly terrain depend strongly on the hill slope and upstream condition, especially inflow turbulence. Numerical simulations are carried out to investigate the neutrally stratified turbulent boundary layer over two-dimensional hills. Two kinds of hill shape, a steep one with stable separation and a low one without stable separation, two kinds of inflow condition, laminar turbulent, are considered. An auxiliary simulation, based on the local differential quadrature method and recycling technique, is performed to simulate the inflow turbulence be imposed at inlet boundary of the turbulent inflow, which preserves very well in the computational domain. A large separation bubble is established on the leeside of the steep hill with laminar inflow, while reattachment point moves upstream under turbulent inflow condition. There is stable separation on the side of low hill with laminar inflow, whilw not turbulent inflow. Besides increase of turbulence intensity, inflow can efficiently enhance the speedup around hills. So in practice, it is unreasonable to study wind flow over hilly terrain without considering inflow turbulence.

• 터널과지하공간
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• 제23권6호
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• pp.547-560
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• 2013

최근 전 세계적으로 에너지 수급의 불안정 및 기후변화에 의한 이산화탄소 저감의 필요성으로 인하여 신재생에너지에 대한 중요성은 점차 증가하고 있다. 이러한 상황에서 지난 2010년 12월에 시작되어 진행 중인 한국 최초의 포항 인공지열 저류층 생성 기술 (Enhanced Geothermal System; EGS) 지열발전소 프로젝트는 국내 EGS 관련기술 발전에 새로운 계기가 될 것이다. 본 논문은 국내 EGS 실증사업에 일부분이라도 도움이 되고자 미국 Fenton Hill 및 일본 Hijiori 프로젝트 연구사례를 살펴보고, 이를 통해 기존 EGS 프로젝트의 성과와 한계를 습득함으로써 국내 EGS 프로젝트의 시행착오를 최소화하는데 도움이 되고자 한다.

• 한국작물학회지
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• 제24권2호
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• pp.57-63
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• 1979

본 시험은 수도 만식재배에 있어 m^2당 재식밀도나 주상묘수를 달리 하였을때 수량구성 요소 및 수량에 미치는 영향을 구명코져 실시하였든바 그 결과를 요약하면 다음과 같다. 1 . 재식밀도의 증가와 주당묘수의 증가는 단위면적당 수수와 영화수를 증가시켜 수량의 증대를 가져왔다. 2 재식밀도의 증가, 주당묘수의 증가는 단위면적당 엽신장과 엽신의 건물중을 높여 영화수를 증가시켰다. 3. 재식밀도의 증가는 단위면적당 엽면적과 건물중을 높여 수량을 증대시키는 요인이 되고 있다. 4. 밀양2001의 만식기는 m^2당 재식밀도는 28~33주, 주당묘수는 6본식으로 하는 것이 유리할 것으로 본다.

• 한국대기환경학회지
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• 제12권4호
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• pp.459-472
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• 1996

An experimental investigation on the wind flow over smooth bell-shaped two-dimensional hills with hill slopes (the ratio of height to half width) of 0.3 and 0.5 is performed in an atmospheric boundary-layer wind tunnel. Two categories of the models are used in the present investigation; six two-dimensional single-hills, and four continuous double-hills. The measurements of the flow field and surface static-pressure distribution are carried out over the Reynolds number (based on the hill height) of 1.9 $\times 10^4, 3.3 \times 10^4, and 5.6 \times 10^4$. The velocity profiles and turbulence characteristics are measured by the pitot-tube and X-type hot-wire anemometer, respectively. The undisturbed boundary-layer profile on the bottom surface of the wind tunnel is reasonably consistent with the power-law profile with $\alpha = 7.0 (1/\alpha$ is the power-law exponent) and shows good spanwise uniformities. The profiles of turbulent intensity are found to be consistent along the centerline of the wind tunnel. The measured non-dimensional speed-up profiles at the hill crest show good agreements with the predictions of Jackson and Hunt's linear theory. The flow separation occurs in the hill slope of 0.5, and the oil-ink dot method is used to find the reattachment points in the leeside of the hill. The measured reattachment points are compared with the numerical predictions. Comparisons of the mean velocity profiles and surface pressure distributions between the numerical predictions and the experimental results show good agreements.