• 한국수자원학회논문집
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• 제56권8호
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• pp.509-520
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• 2023

가뭄은 강수량, 토양수분 그리고 유출량 등 여러 가지 요인으로부터 영향을 받으며, 가뭄의 상황 판단을 위하여 다양한 가뭄지수가 널리 활용되고 있다. 가뭄지수의 산정에 활용되는 수문기상학적 자료와 가뭄지수 산정공식에 따라서 지수값은 달라지며, 가뭄 상황에 대한 판단에도 차이가 발생 할 수 있다. 본 연구에서는 국내외에서 널리 활용되는 표준강수지수(SPI)의 산정과정에서 결정해야 하는 강수량의 자료길이, 누적기간, 확률분포 모형, 매개변수 추정기법 등을 불확실성 영향 요인으로 가정하고, 각각의 조합에 대한 불확실성을 평균제곱근오차와 선형혼합모형(LMM)을 활용하여 평가하였다. 평균제곱오차는 SPI 산정과정에 발생되는 전반적인 오차를 추정하며, LMM은 영향 요인들의 상대적인 불확설성을 평가하는데 활용되었다. 그 결과, SPI 산정에 활용된 자료의 기간과 누적기간이 길어질수록 평균제곱오차가 감소하였다. LMM을 통하여 불확실성 영향요인들의 기여도를 비교한 결과, SPI의 불확실성에는 자료기간의 영향이 가장 크게 나타났다. 또한, 자료기간이 증가하면, 자료기간에 의한 불확실성은 감소하고 누적기간과 매개변수 추정기법에 의한 불확실성이 상대적으로 증가하였다. 본 연구 결과, SPI 산정과정에서 발생되는 불확실성을 줄이기 위해서는 장기간의 자료 확보가 우선이며, 자료의 특성을 적절히 반영하는 확률분포모형과 매개변수 추정기법이 적용되어야 한다.

• 한국약용작물학회지
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• 제20권2호
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• pp.89-93
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• 2012

An important factor in the production of organic ginseng is the control of $Alternaria$ blight and anthracnose, which mostly affect the leaves in the summer. We compared the effects of a lime-bordeaux mixture (LBM) and agricultural chemicals on the growth characteristics and ginsenoside content in 4-year-old ginseng plants when they were sprayed at 15-day intervals from mid-June to the end of September. The increases in leaf length, and survive-leaf ratio in plants sprayed with LBM were greater than the increases of the control plants, but less than those of agricultural chemicals treatment. The root weight per plant in the plants sprayed with LBM increased more distinctly than that in the control plants, while it was significantly lower than that in plants sprayed with agricultural chemicals. The root yield in plants sprayed with LBM increased by 21% compared to the root yield in the control plants, but decreased by 7% compared to that in plants sprayed with agricultural chemicals because of the decreases in leaf area and survive-leaf ratio. Spraying of LBM had a significant effect on the ginsenoside contents. The total ginsenoside content was highest in the control plants and lowest in the plants sprayed with agricultural chemicals and total ginsenoside contents was great relative to survive-leaf ratio and root weight.

• 한국약용작물학회지
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• 제12권6호
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• pp.483-489
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• 2004

경기도 안성지역의 $4{\sim}6$년생 재래종 (자경종) 인삼포장에서 4월 28일에서 9월 30일까지 월별 지하부 생육특성과 엑스함량의 경시적 변화를 조사한 결과는 다음과 같다. 1. 동체장은 월별 수축과 회복을 반복하여 9월 수확기까지 증가되지 않았으나 동체직경은 점진적인 증가를 보였다. 2. 단위 면적당 지상부중은 4월부터 급격히 증가하여 7월에 최고를 보인 후 차차 감소되었으며, 지하부중은 5월에 감소된 후 9월 수확기까지 점차 증가되었는데, 6년생은 7월 이후 약간의 감소를 보였다. 3. 지하부의 상대생장율은 전엽기인 5월과 고온기인 8월에 감소되었고 6, 7, 9월에 다시 증가되었는데, 6년생의 지근과 세근은 $4{\sim}5$년생에 비해 월별 뚜렷한 변화를 보이지 않았다. 4. 상품비율 (근중 60g 이상)은 연생이 증가할수록 커서 4년생 23%, 5년생 60%, 6년생 69% 이었다. 5. 뿌리의 수분함량은 수확기까지 차차 감소되었는데, $7{\sim}9$월까지 유의적인 차이를 보이지 않았으며, 9월 수확기의 수분함량은 4년생 > 5년생 > 6년생순 이었다. 6. 동체의 경도는 5월에 감소된 후 급격히 증가되었는데, $4{\sim}5$년생은 $6{\sim}9$월까지 대체로 증가되었으나 6년생은 8월부터 차차 감소되어 $4{\sim}5$년생과 유의적인 차이를 보였다. 7. 동체와 지근의 엑스함량은 4월부터 6월까지 급격히 감소된 후 9월에 다시 증가되었는데, $4{\sim}5$월의 엑스함량은 4년생이 $5{\sim}6$년생보다 많았으나 9월에는 연생 간에 뚜렷한 차이가 없었다.

• 한국초지조사료학회지
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• 제39권3호
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• pp.153-157
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• 2019

Salicylic acid (SA) is an essential plant growth regulator that functions as a signaling molecule in plants. The purpose of this study was to clarify how the exogenous application of SA counteracts aluminum stress-induced growth and biomass yield reduction in alfalfa exposed to aluminum (Al) stress. Two-week-old alfalfa seedlings were exposed to a combination of $AlCl_3$ ($0{\mu}M$, $50{\mu}M$ and $100{\mu}M$, respectively) and SA (0.1 mM) for 72 hours. We observed, Al stress-induced plant growth inhibition and forage yield reduction are Al stress-dependent manner. A significant reduction of plant height (42.0-52.9%), leaf relative water content (13.0-21.4%), root length (35.4-48.7%), shoot fresh weight (31.2-25.9%), root fresh weight (15.4-23.3%), shoot dry weight (12.7-22.2%), roots dry weight (47.3-53.5%), were observed in alfalfa. In contrast, SA alleviated the Al-stress and enhanced growth and biomass yield in alfalfa. This study provides useful information concerning the role of SA that counteracts aluminum stress-induced growth and yield reduction in alfalfa.

• International Journal of Fluid Machinery and Systems
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• 제7권1호
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• pp.1-6
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• 2014

The propellant acquisition vane (PAV) is a key part of a vane type surface tension propellant management device (PMD), which can manage the propellant effectively. In the present paper, the fluid transportation behaviors for five PAVs with different sections were investigated by using microgravity drop tower test. Further, numerical simulation for the propellant flow in a PMD under microgravity condition was also carried out based on VOF model, and showed the similar flow pattern for PAVs to the experiment. It is noted that the section geometry of PAVs is one of the main factors affecting the fluid transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 have larger propellant transportation velocity. Based on the experiments, there were two stages during the process of propellant transportation under microgravity environment: liquid relocation and steady transportation stage. It is also recognized that there is a linear correlation between liquid transportation velocity and relative time's square root. Those results can not only provide a guideline for optimization of new vane type PMDs, but also are helpful for fluid control applications in space environment.

• 한국토양비료학회지
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• 제22권2호
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• pp.127-130
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• 1989

Perlite에 묘삼을 심고 14일간 여러농도의 $CO_2$를 근권에 처리하고 인삼의 생육상태를 조사하였다. 6~8%에서 완전 출아소요 일수가 3일간 단축 되었으며 13%이상에서 출아가 지연되었다. 14일처리후 경장은 $CO_2$농도가 높을수록 적었다. 64일후의 생육량의 증가율은 8%를 장점으로 증가한 후 감소하는 경향을 보였으나 유의성은 없었다. 22%의 64일간 처리는 65% 출아 되었으나 경장은 60% 감소되었고 35%의 처리는 모두 면삼(眠蔘)이 되었다. 이상의 결과는 인삼의 생육조절 및 저장에 $CO_2$가 활용될 수 있음을 시사한다.

• 생명과학회지
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• 제10권6호
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• pp.598-604
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• 2000

This study was conducted to investigate the effect of simulated acid rain (SAR) on germination, growth, acid buffering capacity and nutrient leaching in Impatiens balsamina L. and Tagetes patula L.. In both species, germination was not inhibited at pH 4.0, but the germination rate decreased at the lower pH of 3.0, showing higher rate in Inpatiens balsamina L. than Tagetes patula L.. As the pH decreases, the growth of radicle was markedly decreased than that of hypocotyl in both species. The plant height, root length, leaf area, total dry weight, relative growth rate and net assimilation rate were inhibited by SAR. The acid buffering capacity in the leaves were increased at pH 4.0, on the other hand, it was shown a tendency to decrease at pH 2.0 in both species. As the pH levels decreased from 5.6 to 2.0, the nutrient leaching from leaves was significantly increased in both species. Based on the results, there are a great difference in the responses to SAR between the two species. In general, Tagetes patula L. represented a higher tolerance to SAR than Impatiens balsamina L.. These results suggested that interspecific variation in the acid buffering capacity and nutrient leaching from leaves may be responsible for the interspecific susceptibility to SAR.

• 한국작물학회지
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• 제32권4호
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• pp.471-475
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• 1987

인삼의 계절적 물질생산과 생장특성을 분석하고 식물체내의 무기양분의 변화를 조사하기 위하여 19-85년에 2년생 인삼을 공시하여 시험한 결과를 요약하면 다음과 같다. 1 엽의 생장은 6월상순, 경장의 성장은 6월하순에 각각 완료되었다. 2. 생육시기별 근중변화는 V자형을 보였다 즉, 5월하순까지는 근중이 감소되었다가 그 이후에는 다시 증가되었으며 9월후에도 근중증가가 인정되었는데 근중증가 완료는 낙엽기에 좌우될 것이다 3. 근의 길이 생장은 5월상순부터 시작되어 8월 상순에 완료되었다. 4. 상대생장률, 순동화율 및 개체군생장 속도는 출아직후에 부치를 보였으며 5월에 최대치를 보였고 그후 점차 감소되었다. 5. 엽면적비는 30~76$\textrm{cm}^2$/g의 범위로 5월에 최대치를 보였으며 그 후 점차 감소되었다. 6. 지상부에 함유되에있는 질소, 가리의 함량은 생육후기에는 감소되였으나 석회의 함량은 증가되었고 인산과 마그네슘의 함량은 생육시기에 따른 변화가 인정되지 않았다 7. 근에 함유되어 있는 질소, 인산, 가리의 함량은 지상부생육 성기에 급격히 감소되었고 생육후기에는 증가되었으나 석회 및 마그네슘의 함량은 생육시기에 따른 변화가 인정되지 않았다.

• 한국연초학회지
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• 제3권1호
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• pp.58-65
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• 1981

This study was carried out to investigate the influence of distance of planting holes (51, 45, and 40 cm) and number of plants per a hole(4, 5, 6 plants) on agronomic characteristics, yield, and quality of an aromatic tobacco, Sohyang. The results are as follows: 1. Relative light intensity increased by widening the distance of holes. 2. Leaf area per a plant or per a leaf, and leaf length and width increased by widening the distance of holes and decreased by increasing the number of plants per a hole. But L. A. 1. increased by increasing the number of plants per a hole. Leaf shape index (Leaf length/Leaf width) showed little differences among treatments. 3. Dry weight of leaf, root, and stem per a plant decreased by increasing the number of plants per a hole. 4. Total nitrogen decreased by increasing number of plants per a hole and in the case of narrow distance of holes, but nicotine, reducing sugar, ether-extract and ash showed little differences. 5. Yield per 10a decreased by widening the distance of holes. 6. Quality(price per kg) was improved by increasing the number of plants per a hole at the Plot of 51m distance of holes. But there was no variation at the Plot of 45cm. And quality was decreased at the plot of 40cm distance of holes by increasing the number of Plants per a hole. 7. Price per 10a was highest in the plot of which plant spacing was $90\times$40cm and the number of plants per a hole was 4 (11112 plant/10a).

• Imaging Science in Dentistry
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• 제40권3호
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• pp.115-121
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• 2010

Purpose : The purpose of this study was to accurately analyze the radiographic characteristics of dentigerous cyst (DC) with multiplanar images of cone beam computed tomography (CBCT). Materials and Methods : Thirty eight radiographically and histopathologically proven cases of DCs were analyzed with panoramic radiograph and CBCT, retrospectively. The radiographic CT pattern, symmetry of radiolucency around the unerupted tooth crown, ratio of long length to short length, degree of cortical bone alternation, effects on adjacent tooth, and cyst size were analyzed. Relative frequencies of these radiographic features were evaluated. In order to compare the CBCT features of DC with those of odontogenic keratocyst (OKC), 9 cases of OKCs were analyzed with the same method radiographically. Results : DCs consisted of thirty unilocular cases (79.0%), seven lobulated cases (18.4%) and one multilocular case (2.6%). Eight were asymmetric (21.0%) and thirty were symmetric (79.0%). Maxillary DC showed rounder shape than mandibular DC (L/S ratio; maxilla 1.32, mandible 1.67). Alternations of lingual cortical bone (14 cases, 48.2%) were more frequent than those of buccal side (7 cases, 24.1%). CBCT images of DC showed definite root resorption and bucco-lingual tooth displacement. These findings were hardly observed on panoramic radiographs of DCs. Comparison of CBCT features of DC with those of OKC showed several different features. Conclusions : CBCT images of DC showed various characteristic radiographic features. Therefore, CBCT can be helpful for the diagnosis of DC radiographically.