• 한국잡초학회지
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• 제7권3호
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• pp.280-288
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• 1987

논잡초 올미와 수도(水稻)와의 경합(競合)을 지하부(地下部)를 중심으로 알아보기 위하여 통일형품종(統一型品種)인 중원벼와 일본형품종(日本型品種)인 상풍벼를 공시하여 포장실험을 수행 하였다. 표준재배한 수도(水稻)에 올미괴경을 완전방제구, 4개/$m^2$ 재식구, 8 개/$m^2$ 재식구 및 16 개/$m^2$ 재식구의 4개 밀도로 심고 이앙후(移秧後) 30일, 45일, 60일 및 75일에 경합양상을 조사하였다. 1. 올미괴경의 재식밀도(載植密度)가 증가함에 따라 중원벼와 상풍벼의 초장(草長), 분벽(分蘗) 및 수량(收量)은 감소하였으나 유의(有意)한 차이는 아니었다. 2. 올미괴경의 재식밀도(載植密度)가 증가함에 따라 통일형인 중원벼에서는 근수(根數)와 근중(根重)의 감소가 현저하였으나 일본형(日本型)인 상풍벼에서는 감소정도가 완만하여 중원벼의 경합력(競合力)이 상풍벼보다 작았다. 3. 올미의 뿌리는 이앙후(移秧後) 60일(日)까지에 토양 15cm 깊이에 분포하였으며 0~5cm 깊이에 전체의 64~80%, 5~10cm 깊이에 20~36%. 10~15cm 깊이에 6.7% 이하의 뿌려가 분포하였다. 그러나 출수기 이후에는 토양 0~10cm 깊이에만 분포하였다. 4. 중원벼와 경합한 올미는 이앙 후 45 일에 최대의 생육을 보인 후 근수와 근중이 크게 감소하였 으나 상풍벼와 경합한 올미의 근생육(根生育)은 이앙 후 60일에 최대에 달한 후 완만하게 감소하였다. 5. 올미의 근활력(根活力)은 중원벼보다 55%, 상풍벼보다 40%나 높았다. 6. 올미의 근생육(根生育)은 상풍벼보다 중원벼와 경합시 출수기 이후 크게 억제되었다.

• 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.

• 대한치과보철학회지
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• 제32권3호
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• pp.455-469
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• 1994

Regular radiographic examination has been considered an essential diagnositic method for osseointegrated dental implantation. This study investigated marginal bone loss through the measurement on periapical radiographs and changes in bone density through digital subtraction image radiographic method around 88 endoseous root-form dental implants in 43 human subjects. Four types of endosseous dental implants were investigated : Standard series, Mini series and Hex-lock system of Steri-Oss Dental implant system, and $Br{\aa}nemark$-type implant from 3i dental implant system, in a 3 month interval for a total period of 12 months. The results were as follows : 1. Rapid bone loss occurred in the first 3 months in all 4 groups, and the bone level stabilized at the first thread of the implant fixtures. Amount of bone loss for 12 months showed correlation with the length of the polished neck portion. 2. Most of the implant systems showed resorption of alveolar bone up to the polished neck portion although a long polished neck could delay the resolution. 3. Alveolar bone loss apical to the polished neck portion stabilized at the first thread of the fixtures with no correlation to either the time of exposure of the polished neck or types of implant systems. 4. No changes in bone density around the implant threads were observed throughout the experimental period. Bone density decreased at the marginal bone, and increased at the newly-formed alveolar crest. These results indicate that most of the alveolar bone loss occur within the first 12 months after installation of endosseous root-form dental implants resulting in the exposure of polished neck portions, and the bone level stabilizes thereafter at the first thread portions of the implant fixtures. The experimental period of 12 months seems insufficient for observing changes in bone density, and a long-term observation should be needed.

• Journal of Ginseng Research
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• 제22권2호
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• pp.96-101
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• 1998

This paper describes the determination of bulk density and the discrimination of internal structure of red ginseng by nuclear magnetic resonance (NMR). The 102 red ginseng roots were tested for bulk density. The NMR properties measured by NMR parameters such as spin-lattice relaxation time ($T_1$) and spin-spin relaxation time ($T_2$) were determined using the low field proton NMR analyzer. Bulk density of red ginseng root showed a highly negative significant correlation (r=-0.8934) with the value of $T_1$, but a highly positive significant correlation (r=0.7672 and 0.5909) with the value of T21 (short T2) and T22 (long T2), respectively. Multiple regression equation, Y=-0.0069.$T_1$+0.3044.$T_{21}$-0.0156.$T_{22}$-0.6368, using the MNR parameter values of 80 red ginseng roots can effectively predict the bulk density of 22 red ginseng roots with the correlation coefficient of 0.9396 and the standard error of 0.086. The differences in the internal structure of normal and inside white part of red ginseng were easily found by the signal intensity of NMR image based on magnetic properties of proton nucleus.

• 아시안잔디학회지
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• 제14권1호
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• pp.273-280
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• 2000

This study was conducted to evaluate an efficiency of plant growth regulator trinexapacethy(Primo) on the growth response of bentgrass and the change to soil water content in bentgrass green. Based on the results of the study, the following results were observed. 1. During four weeks after treatment, the visual color and turfgrass density of all the treated plots with trinexapac-ethyl(Primo) were more improved rather than without. Two treatments trinexapac-ethyl /$0.02mL\m^2$ and $0.04mL/\m^2$ were more favorable than other treatments. 2. It suggested that optimum rate to reduce the bentgrass growth and to increase the turfgrass density was the trinexapac-ethyl $0.04mL/\m^2$. 3. For six weeks after treatment, all treated plots were not significantly different (P<0.05) in turfgrass root length and root dry weitht. 4. In the treated plots with trinexapac-ethyl $0.04mL/\m^2$ for 25days in bentgrass green, soil water consumption was approximately 35% to 40% compare to the non-treated control.

• 한국조경학회지
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• 제28권4호
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• pp.1-8
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• 2000

This study is conducted to evaluate the effects of root restriction on growth of maple(Acer palmatum Thumb.). Tow types of container such as clay pot(CP), root control bag(RCB) were used to restrict maple's root and each type of container was divided into 5 sizes. The containers with plants were buried just below the soil level and maples planted directly in the soil (nonrestricted root treatment) were included as comparison. Data were collected on dry weight of leaf, trunk, thick root, rootlet and soil water potential. We have analyzed, simple linear regression, Pearson's Correlation analysis, Duncan's multiple rang test, and Covariance Analysis using SAS statistical software. The results of analysis based on these data are as follows; 1. Total dry weight of maple in CP was significantly larger than in RCB. 2. Difference in growth reduction by the kinds of containers was induced by different hydraulic diffusion ratios between container and soil. Difference in growth reduction by the size of container was induced by the difference density of rootlet and soil moisture contents in the container. 4. Commercial products of root control of root control bag appeared not proper for countries in which fluctuation of rainfall is severe. Because maples in RCB were restricted by excess soil water in the rainy season, or by lack of soil water in the dray season.

• Journal of Ecology and Environment
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• 제38권1호
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• pp.57-65
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• 2015

A natural mixed stand of Phragmites australis and Phacelurus latifolius was studied to clarify the distribution properties in a microsite in a tidal flat of Suncheon Bay. The height, density, and biomass of the shoots, as well as the biomass of the root system, were monitored for both species along with the altitude on a mound from June 2010 to October 2013. Firstly, the mean height and dry weight of both species were similar during the growth season. However, individual variations of the sizes of plants in the same species were noticeable. Secondly, the density and dry weight per unit area of P. latifolius increased, but that of P. australis decreased with the altitude on the mound. Thirdly, the root system (rhizomes and roots) of P. latifolius was mostly located in the upper layer (up to 20 cm depth), while that of P. australis was in the lower layer (over 70 cm depth) of the sediment. The roots of P. australis penetrated to the lower parts of the water table, while the roots of P. latifolius did not make contact with free water of the sediment. Fourthly, the removal of the shoot in the early growth season led to a visible reduction of biomass in the late growth season. The reduction rate was larger in P. latifolius than in P. australis. Lastly, in the area where the mound was removed, the density of P. australis increased in the first two years (2010-2011) and was highly sustained inthe last two years (2012-2013). However, the density of P. latifolius was low, and this plant was distributed at the edge of the mound only.

• 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.

• 한국약용작물학회지
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• 제25권4호
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• pp.244-251
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• 2017

Background: The application of crop rotation systems may reduce the occurrence of soil-borne diseases by releasing allelochemicals and by subsequent microbial decomposition. Methods and Results: For reduction of ginseng root rot by the crop rotation system, after harvesting 6-year-old ginseng, fresh ginseng was grown along with continuous cultivation of sweet potato, peanut, and bellflower. Growth of 2-year-old ginseng was significantly inhibited in the continuous cultivation than in the first cultivation. Sweet potato, peanut and bellflower cultivations assisted in obtaining normal yields of ginseng in the first year after the harvest of 6-year-old ginseng. Salt concentration, potassium and sodium contents were gradually decreased, and, organic matter was gradually increased through cirp rotation. Phosphate, calcium and magnesium contents were not altered. The density of the root rot fungus was gradually decreased by the increase in crop rotation; however it was decreased distinctly in the first year compared to the second and third year. The severity of root rot disease tended to decrease gradually by the increase of crop rotation. Conclusions: Short-term crop rotation for three years promoted the growth of ginseng, however root rot infection was not inhibited significantly, although it was somewhat effective in lowering the density of the root rot pathogen.

• 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.