• 한국농공학회지
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• 제24권2호
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• pp.56-66
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• 1982

This study was carried out in order to estimate water losses in irrigation canals, which may be used to evaluate the water requirement for irrigation projects. The conveyance losses were measured by the inflow-outflow method, the seepage losses were measured by the ponding method, and the operation losses in the course of irrigation were calculated by comparing the two kinds of losses. The results obtained in this experiment were as follows; 1. Conveyance losses per unit area of wetted perimeter by the main irrigation canal, the secondary irrigation canal and the tributary irrigation canal, were 1.399${\times}10^{-5}m^3/sec/m^2$, 5.154${\times}10^{-5}m^3/sec/m^2$, and 2.67${\times}10^{-5}m^3/sec/m^2$ respectively in the Goong-sa area. And they were 1.934${\times}10^{-5}m^3/sec/m^2$, 2.149${\times}10^{-5}m^3/sec/m^2$, and 4.558${\times}10^{-5}m^3/sec/m^2$ respectively in the Seong-dug area. 2. Seepage losses per unit area of wetted perimeter by the secondary irrigation canal and the tributary irrigation canal, were 2.180${\times}10^{-6}m^3/sec/m^2$ and 2.168${\times}10^{-6}m^3/sec/m^2$ in the Goong-sa area, 1.150${\times}10^{-6}m^3/sec/m^2$ and 1.084${\times}10^{-6}m^3/sec/m^2$ in the Seong-dug area respectively. 3. Operation losses per unit area of wetted perimeter by the secondary irrigation canal and the tributary irrigation canal, were 4.936${\times}10^{-5}m^3/sec/m^2$ and 2.453${\times}10^{-5}m^3/sec/m^2$ in the Goong-sa area, 2.034${\times}10^{-5}m^3/sec/m^2$ and 4.450${\times}10^{-5}m^3/sec/m^2$ in the Seong-dug area respectively. 4. Conveyance, seepage and operation losses in the Goong-sa area were 6.7%, 94.6%, and 14.0% more than those in the Seong-dug area. Operation losses amount to about 17 times as much as seepage losses in the Goong-sa area and about 29 times in the Seong-dug area. 5. The seepage losses depend much on the soil texture, ranging from 7.437${\times}10^{-7}m^3/sec/m^2$ to 2.430${\times}10^{-6}m^3/sec/m^2$. 6. Water loss rates in the main irrigatin canal, the secondary irrigation canal and the tributary irrigation canal, were estimated as 8.49%, 37.27% and 9.81% respectively in the Goong-sa area. And they were estimated as 15.10%, 32.67% and 13.78% respectively in the Seong-dug area.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권5호
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• pp.33-36
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• 2007

최근 들어 preferential flow같은 현장조건의 불균질한 매질을 이동하는 지하수 거동해석에 이류 분산 방정식을 적용하는데 많은 문제점들이 제기되어 왔다. 이에 따라 Kim 등(2005)은 최소한의 모형인자로 preferential flow 경로를 통한 토양지하수의 흐름을 예측할 수 있는 간단한 모형을 개발한 바 있다. Kim 등(2005)이 제시한 Generalized Preferential Flow Model(GPFM)은 토양을 표층주변의 분배 층(distribution layer)과 그 밑의 운반구역(conveyance zone)으로 나누어 거동을 예측하고 있다. 본 연구에서는 GPFM을 간단히 소개하고 기존의 다른 실험결과에 적용한 후 이류분산방정식(CDM)과의 비교를 통해 모형을 검증해 보고자 하였다. 기존에 발표된 두 개의 실험값에 GPFM을 적용해본 결과, GPFM은 세 가지 인자-유효함수비, 유속, 분산계수-를 입력하여 silty 및 sandy loam 토양 내 추적자의 파과곡선을 잘 예측하였다. CDM을 이용한 예측 값과 비교한 결과 GPFM과 CDM 모두 실제 관측된 파과곡선과 일치된 경향을 보였으나, GPFM에 의해 추측된 인자들이 더 현실적으로 가능한 값을 나타내었다. 인용된 두 실험값에 GPFM을 적용할 경우 예측 값에 가장 영향을 끼친 인자는 유효함수비로 나타났는데, 이는 Kim 등(2005)이 같은 종류의 토양에서 유속이 GPFM의 결과에 가장 영향을 끼쳤다고 보고한 것에 비해, 다른 성질의 토양에서는 유효 함수비가 가장 결정적인 인자임을 보여준다. 본 연구를 통해 GPFM이 이용하기가 쉽고 여러 가지 현장조건에 적용성이 높아 preferential flow 경로를 통한 토양지하수의 흐름을 예측할 수 있는 유용한 도구임을 확인하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.26-32
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• 2008

Middle Route Project, the largest water conveyance system in China delivers the water of Changjiang River to North China. In order to create canal operation simulation system, mathematical models are established based on the analysis of hydraulics about steady flow, unsteady flow, and check gate. By simulating the canal operation behavior, we improved the check gate control algorithm and predicted the change process of water surface and flow profile which is very valuable to actual canal operation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.186-189
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• 2003

Precast Segmental method was developed in germany 1950s. This method has been adoptted in long span girder mainly owing to easy construction effect. But, so far, The limit exists that this method is constructed in a portion of span and hard conveyance and foundation. This study was performed to analysis behavior difference of two rectanglar section girder, spliced girder that was jointed 5-sliced 0.8m segment and monolithic girder that was produced in one body 4m span

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.131-136
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• 1998

Based on the linear model of electromagnetic suspension (EMS) system, it is able to be further simplified into a standard second-order model with a modified PD control. In this paper static and dynamic characteristics of EMS with modified PD control are investigated when suspended weight of steel plate change. A experimental system has been built to verify static and dynamic characteristics of EMS system. Simulation and experiment are both given.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.89-92
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• 2004

Precast Segmental method was developed in germany 1950's. This method has been adoptted in long span girder mainly owing to easy construction effect. But, so far, The limit exists that this method is constructed in a portion of span and hard conveyance and foundation. This study was performed to analysis behavior difference of two rectangular section girder, spliced girder that was jointed 5-sliced 0.8m segment and monolithic girder that was produced in one body 4m span.

• Journal of Biosystems Engineering
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• 제26권6호
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• pp.563-570
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• 2001

To develop a stalk detaching system the effect of shape factor of red pepper affecting the performance of unfolding, arranging and cutting was analysed. The obtained results are as follows : By cutting experiment, it was found that the bending of stalk affected the cutting rate of stalk, and that the bending of body increased the amount of peppers that were expelled from the cutting guide by conveying brush. The ratios, 'bending length of a body/body length'and 'bending length of a stalk/stalk length', could be used as criteria far abnormality of body and stalk of peppers, respectively. As a result of experiment, it was concluded that mechanical treatment would be difficult for the peppers with indexes greater than 0.4 and 0.3 fur body bending and stack bending. respectively. So, these indexes were used as criteria for distinguishing abnormality from normality of peppers. In the unfolding unit, conveyance of peppers was impossible for both of normal and abnormal ones at the inclination angle of 10°, especially, at the frequency of 8.3 Hz peppers maintained stationary state. At the inclination angle of 20°, both of normal and abnormal peppers showed similar tendencies, but abnormal ones showed an accumulation trend gradually with increased feeding speed. In the arranging unit, conveyance of peppers was almost impossible for both of normal and abnormal ones at the inclination angle of 20°, showing almost no difference between the conveyances of normal and abnormal ones. In the case of the inclination angle of 30°, at the condition of the feeding speeds and frequency corresponding 0.06 m/s, 0.08 m/s and 8.3 Hz, respectively, the passing time of the abnormal peppers on the arranging plate increased rapidly.

• 대한토목학회논문집
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• 제31권4B호
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• pp.323-332
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• 2011

하천에서 수목의 관리를 위해서는 수목이 홍수에 미치는 영향이나 생태적 특성을 고려하여 대책을 수립하여야 한다. 수목에 의한 수리학적 영향은 통수능 감소와 유수력에 의한 전도로 인한 하류 하천시설물의 기능 저해이다. 현장 인발시험은 수목이 전도될 때의 최대 저항력을 측정하여, 하천 내의 수목이 외력에 저항하는 정도를 파악하기 위해 시행하였다. 수목의 전도모멘트를 파악하기 위한 인자는 수목의 외형적 특성인 수종, 흉고직경, 수고 등이며, 본 연구에서는 전도모멘트와 흉고 직경의 상관관계를 이용하였다. 수목의 한계 전도모멘트는 흉고직경 4.9-32.8 cm의 관목과 교목 100주를 바탕으로 검토되었다. 교목과 관목을 함께 고려할 경우에는 흉고직경과 한계 전도모멘트의 상관관계를 도출하기 어려웠다. 그러나 교목만을 고려할 경우에는 흉고직경과 한계 전도모멘트 사이에 일정한 상관관계가 있음을 확인하였다.

• 한국정밀공학회지
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• 제26권9호
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• pp.72-80
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• 2009

When the magnet wheel rotates over a conducting plate, it generates the traction torque as well as the repulsive force on the conducting plate. Partially-cut traction torque results in the linear force into the tangential direction. To cut the traction torque, the concept of magnetic shield is introduced. The direction change of the linear force is realized varying the shielded area of magnetic field. That is, the tangential direction of non-shielded open area becomes the direction of the linear thrust force. Specially a shape of permanent magnets composing the magnet wheel leads to various pattern of magnetic forces. So, to enlarge the resulting force density and compensate its servo property a few simulations are performed under various conditions such as repeated pattern, pole number, radial width of permanent magnets, including shape of open area. The theoretical model of the magnet wheel is derived using air-gap field analysis of linear induction motor, compared with test result and the sensitivity analysis for its parameter change is performed using common tool; MAXWELL. Using two-axial wheel set-up, the tracking motion is tested for a copper plate with its normal motion constrained and its result is given. In conclusion, it is estimated that the magnet wheel using partial shield can be applied to a noncontact conveyance of the conducting plate.

• 원예과학기술지
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• 제33권5호
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• pp.697-704
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• 2015

본 연구는 절화 국화 'Baekma'를 일본으로 선박 수출 시 수송 환경을 분석하였으며, 절화 국화의 선도를 유지하기 위한 최적 전처리제를 구명하고자 하였다. 그 결과 일본으로 절화 국화를 수출시 약 3일~5일이 소요되었으며, 국내 이동, 선박 운송 및 일본 내에서 이동은 저온이 유지되었으나, 일본에서 검역시 상온에 노출되는 것으로 조사되었다. 이는 품질의 손상을 야기하는 것으로 수송 전체 기간동안 저온조건을 유지해야 할 것으로 판단되었다. 또한, 전처리제는 Chrysal RVB, NaOCl 처리구가 절화수명 연장에 효과적이었으며, Chrysal RVB 전처리는 절화 국화가 끝까지 만개하여 화형이 유지되었다. 박테리아 검정 결과 NaOCl, $ClO_2$ 처리구의 박테리아가 검출되지 않아 살균 성분이 세균증식을 막아준 것으로 판단되었다. 그러나 $ClO_2$처리구는 수확 후 초기 생육에 영향을 미치는 것으로 사료되었다. Chrysal RVB 처리 및 NaOCl 처리구의 엽록소 함유량이 가장 높은 것으로 조사되었다.