• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.792-801
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• 1996

A thinning algorithm -based image analysis technique was developed to measure corn root lengths. The root length measurement method was evaluated by comparing thread lengths measured by the image analysis system with actual thread lengths. The length measurement method accurately estimated actual thread lengths (less than 2% calculated error). Also, a rapid root length density measurement procedure, which utilizes the above root length measurement method, was developed to estimate corn root length density without washing the roots. Root length densities estimated from the cut soil surface of core samples taken from the field were paired with the root length densities determined from washed roots from the same soil core sample. A linear relationship between these two values was expected and was found. Eliminating the root washing procedure reduces the time required for measuring corn root length density substantially.

• Plant Resources
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• 제4권1호
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• pp.6-12
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• 2001

Growth and yield of licorice were investigated under the different conditions of ridge height, planting density, and irrigation in order to establish its cultural practices for the domestic production with the aim to substitute the import. Seedlings were grown under low ridge(20cm) and high ridge(40cm) in low density plot(60$\times$30cm) and high density plot(40$\times$30cm), respectively. The low ridge cultivation of large seedlings increased plant height and root length under low density, and stem and root diameter under high density compared to the high ridge cultivation. In the high ridge cultivation, high density plot was 1.1 to 1.3 times in plant height, root length, stem and root diameter as high as low density one. Fresh and dry weight of plant and root in high ridge were 1.3 to 1.5 times as high as those in low one. The growth of small seedlings(4~10g) were generally poor compared to that of large seedlings. High density plot in low ridge showed the good growth characteristics including plant height, root length, stem and root diameter, and number of branch. High density plot was 1.4 to 1.6 times in fresh and dry weight of plant and root as high as low density plot. In the seasonal changes of growth under various irrigation regimes, the twice irrigation a day produced the more number of leaf than the other regimes since around 46 days after transplanting. The former irrigation resulted in 1.2 to 1.4 times in plant height as long as the other irrigations around 26 days after transplanting and then the difference was increased to 1.6 to 2.0 times around 64 days after transplanting. Under the twice irrigation a day, plant height, root length, stem diameter, root diameter, number of leaf, fresh plant weight, dry plant weight, fresh root weight, dry root weight were 1.6 to 2.0, 1.1, 1.2 to 1.6, 1.3 to 1.8, 1.9 to 2.7, 1.7 to 8.0, 1.6 to 2.8,2.0 to 3.0, 1.6 to 2.7 times as high as those under the other irrigation regimes, respectively.

• 한국작물학회지
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• 제47권6호
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• pp.418-421
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• 2002

백하수오 근수량 증대를 위한 밀식 재배법을 확립하고자 직파와 육묘 이식으로 구분하여 파종하고 재식밀도를 달리하여 시험을 수행한 결과를 요약하면 다음과 같다. 1. 지상부 생육은 파종 방법 간에는 육묘 이식재배에서 양호하였으며, 재식밀도 간에는 밀식할수록 만장과 분지수는 길거나 많았으나, 엽장과 엽폭은 소식할수록 증가하는 경향이었으며, 개체당 엽수는 22주/$m^2$에서 가장 많았다. 2. 지하부 생육은 파종 방법 간에는 육묘 이식재배에서 양호하였고, 재식밀도 간에는 주당 지근수, 근장 및 근태는 소식할수록 많거나 길거나 굵었으나, 단위 면적당 지근수는 밀식할수록 증가하였다. 3. 생근수량은 직파 재배보다 육묘 이식재배에서 많았으며, 재식밀도 간에는 밀식할수록 많아 육묘 이식 17주/$m^2$(1,680 kkg/10a)에 비하여 27주/$m^2$(2,567 kg/10a)에서 53%증수되었다.

• 한국작물학회지
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• 제49권4호
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• pp.284-288
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• 2004

The response of dissolved oxygen (DO) concentrations caused significant change in root number, root length, coleoptile length, shoot length and leaf age of seedlings. The genotypic difference in the effect of DO also highly significant (P<0.01) for all of the seedling traits. The number and length of root were extremely inhibited at the condition of $0.39\pm0.09$ DO concentration. While the coleoptile elongated markedly in the lowest DO concentrations, the shoot did not develop. The root growth was improved slightly at the $1.39\pm0.27mg L^{-1}$, however, there were no difference among genotypes at these two low DO concentrations. As the DO concentration become higher, the growth of root and shoot was improved remarkably. Root number, root length and shoot length was significantly different between $20\;and\;30^{\circ}C$ in DO rich and normal conditions, the development of those traits were apparently accelerated in high water temperature, however those traits of seedlings in DO deficiency were not different between the two temperatures except for shoot length. On the other hand the coleoptile length was not affected by the stagnant water temperature; it was stimulated by the low DO concentration. The competition of DO was greater as the seedling density was increased in the stagnant water, therefore the seedlings grown under high density have long and white coleoptiles, and the growth of roots and shoots was retarded severely.

• 한국초지조사료학회지
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• 제23권2호
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• pp.91-94
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• 2003

비교되는 포장조건에 따라 부리 분포 양상을 조사하기 위하여 Rhizotron법을 사용하였다. Lincoln 지역에서 토양 깊이에 따른 뿌리의 분포는 15∼30 cm 깊이에 대부분의 뿌리가 분포되어 있고, 0∼15 cm와 30 cm 이하에서는 분포가 적었다. 반면, Winchmore에서는 토양 깊이가 깊어질 수록 뿌리 수가 많아졌다. Mt John에서는 표토에 가까울 수록 뿌리 분포도가 더 높았으며, 시비량이 높고 관개를 한 곳이 부리 분포가 더 높았다. 모든 지역에서 토양 깊이에 따른 뿌리 수의 분포는 뿌리 길이와 같은 경향을 보여주었다. Tube법이 같은 장소에서 뿌리의 비교 연구와 장기간 무리 생장 연구를 하는데 좋은 방법임이 입증되었다.

• Journal of Ginseng Research
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• 제19권3호
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• pp.287-290
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• 1995

This study was conducted to elucidate the effect of physical properties of soil in nursery bed with different densities on growth of ginseng seedling. Stem length, leaf length and leaf width of ginseng seedling showed the decreasing tendency with increasing the hardness of the nursery soil. Fresh root weight per seedling and number of available seedlings were increased significantly with decrease of the soil hardness. For solid, liquid phases, bulk density and hardness of soil, negative correlations were shown in stem length, leaf length, leaf width, root weight per seeding, and number t of available seedlings. On the other hand, gas phase, air permeability and porosity of soil had positive correlations with stem length, leaf length, leaf width, root weight per seedling and number of available seedlings. Key words Yang-Jik nursery, ginseng seedling, soil physical properties.

• 대한치과교정학회지
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• 제53권3호
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• pp.205-216
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• 2023

Objective: To investigate changes in the immature teeth of Sprague-Dawley rats during orthodontic treatment and to explore the changes in the peri-radicular alveolar bone through micro-computed tomography (CT). Methods: Twenty-five 26-day-old male Sprague-Dawley rats were included. The maxillary left first molar was moved mesially under a continuous force of 30 cN, and the right first molar served as the control. After orthodontic treatment for 7, 14, 21, 28, and 42 days, the root length, tooth volume, and alveolar bone mineral density (BMD) around the mesial root were measured through micro-CT. Results: The immature teeth continued to elongate after application of orthodontic force. The root length on the force side was significantly smaller than that on the control side, whereas the differences in the volume change between both sides were not statistically significant. Alveolar bone in the coronal part of the compression and tension sides showed no difference in BMD between the experimental and control groups. The BMD of the experimental group decreased from day 14 to day 42 in the apical part of the compression side and increased from day 7 to day 42 in the apical part of the tension side. The BMD of the experimental group decreased in the root apex part on day 7. Conclusions: The root length and volume of immature teeth showed continued development under orthodontic forces. Alveolar bone resorption was observed on the compression side, and bone formation was observed on the tension side.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권2호
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• pp.59-64
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• 2001

The distribution of current in the conductors influenced by the armature geometry and velocity is an important parameter for determining performance of an electromagnetic launcher(EML). the electric current in the early launching stage tends to flow on the outer surfaces of the conductors, resulting in very high local electric current density. However, the tendency for current to concentrate on the surface is driven by the velocity skin effect later in launching stage. The high current density produces high local heating and, consequently, increases armature wear which causes several defects on EML system. This paper investigates the effects of rail/armature geometry on current density distribution, launcher inductance gradient (L'), and contact force. Three geometrical parameters are used here to characterize the railgun system. These are the ratio of contact length to root length, relative position of contact leading edge to root trailing edge, and the ratio of rail overhang to the rail height. The distribution of current density, L', contact force between various configurations of the armature and the rail are analyzed and compared by using the EMAP3D program.

• 한국작물학회지
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• 제38권3호
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• pp.240-244
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• 1993

야콘의 재배기술의 확립을 위하여 멀칭효과 및 재식밀도 실험을 한 결과는 다음과 같다. 1. 지상부 생육은 7월 중순부터 직선적으로 증가하였으며, 밀칭구나 비멀칭구에서 재식밀도가 높을수록 초장의 생육이 양호하였고, 특히 70 ${\times}$ 55cm에서 가장 좋았다. 2. 측지수는 정식 후 3개월부터 발생하였으며, 멀칭 및 재식밀도에 따라 유의한 차이를 나타내지 않았다. 3. 야콘괴경의 생체수량은 멀칭구가 비멀칭구 보다 높았으며, 멀칭구에서는 70${\times}$40cm구가 3561.7kg으로 가장 높았다. 4. 괴근수는 멀칭구에서 밀식할수록 많았으며, 근경과 근장에서는 유의적인 차이가 없었다.

• 한국약용작물학회지
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• 제6권2호
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• pp.137-141
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• 1998

쇠무릎의 적정(適正) 재식밀도(栽植密度)가 생육(生育) 및 수량(收量)에 미치는 영향을 구명(究明)하고자 나주(羅州) 자생수집종(自生蒐集種)을 공시하여 90cm 두둑에 재식밀도(栽植密度)를 조간(條間) 20cm, 25cm, 30cm의 3수준(水準)과 주간(株間) 5cm 7cm, 9cm의, 3수준(水準)으로 처리(處理)하고 시비량(施肥量)을 10a당(當) 실소(室素) 6kg, 인산(燐酸)14kg, 가리(加里)8kg 및 퇴비(堆肥) 1,500kg을 시용(施用) 후(後) 4월(月) 15일(日)에 $4{\sim}5$입(粒)씩 점파(点播)하여 양질(良質)의 생약(生藥) 생산(生産) 및 안정적(安定的)인 재배법(栽培法) 확립(確立)하고자 시험(試驗)한 결과를 요약(要約)하면 다음과 같다. 1. 토양의 화학성(化學性)은 시험후 토양이 시험전 토양에 비해 유기물(有機物), 유효인산(有效燐酸), 칼리, 칼슘, 마그네슘, C. E. C 함량이 증가되는 경향을 보였다. 2. $30{\times}9cm$의 소식(疎植) 재배구(栽培區)에서 경태(莖太)가 굵고 주당(株當) 분지수(分枝數) 및 지근수(枝根數)는 많았으나 $25{\times}5cm$(57, 140주(株)/10a) 구(區)에서 면적당 입모수(立毛數)가 많아 경장(莖長)이 길어지고 세근(細根)이 적어진 반면에 주근장(主根長)과 주근경(主根徑)이 커져 단위(單位) 면적당(面積當) 근수량(根收量)은 증가되었다. 3. 건근수량(乾根數量)은 $25{\times}5cm$ 구(區)에서 $25{\times}5cm$ (306kg/10a)의 밀식구(密植區)에 비하여 상근중(上根重) 비율(比率)이 71%로 높아지고 잔뿌리가 적어져 품질이 향상되어 71% 증수(增收)를 보였다. 4. $25{\times}5cm$ 밀식재배(密植栽培)에서 건근수량(乾根收量)은 경태(莖太), 주당(株當) 분지양(分枝數) 생경엽중(生莖葉重) 및 근수(根數)와는 부(負)의 상관(相關)을 보였으며 경태(莖太), 절수(節數), 주근장(主根長,. 주근경(主根徑) 및 북근중(北根重) 북(比) 율(率) 등(等)과는 정(正)의 상관(相關)이 인정되었다.