• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.41-51
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• 2018

In case of evaluating the bond stress of a void deck plate using a wire steel, there is no standard formula considering both the influence on the void and the type of the reinforcing bar. Therefore we proposed a model equation considered the bond characteristics of the void deck plate. A total of 46 specimens was carried out a direct pull-out test and the test variables were the presence of a void body, type of reinforcing bar, the inner cover thickness according to the location of reinforcing bars and bond region. As a result of the comparison between the steel bar and steel wire, the bond stress of the steel wire with the relative rib area of 0.071 is 4.5 ~ 28.58% lower than that of the steel bar with 0.092 and the bond stress reduction rate increases when the inner cover thickness is insufficient. In the case of the inner cover thickness of $1.7d_b$ and $2.7d_b$, the bond stress was reduced to 48.7 ~ 68.4%. In the inner cover thickness was $4.9d_b$ and $5.2d_b$, the bond stresses were equivalent to those of the solid specimens. It was confirmed that the average bond stress and strain were affected by the inner cover thickness. Therefore the predicted model for one module of the void deck plate is proposed and verified by considering the bond characteristics of the void deck plate.

• Journal of Agricultural Extension & Community Development
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• v.7 no.1
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• pp.167-173
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• 2000

This study was carried out to investigate suitable pruning methods to avoid poor berry setting of 'Kyoho' grapevine in Suwon and Anseong areas. Light pruning increased percentage of bud bursts and number of shoots per bearing mother branches(BMB), cluster weight and percentage of berry sating but it decreased shoot length, number of leaves and, leaf area and leaf weight. There was little difference in soluble solids, titratable acidity, and anthocyanin contents of berries by the treatment of either light or heavy pruning. Shoot length became longer as diameter of BMB thickened, leaf area and chlorophyll content also became larger and diameter of BMB. Total carbohydrate and N, P, K, Ca, and Mg contents showed significantly little difference, but total carbohydrate and Ca contents showed a tendency of continuous increase as diameter of BMB thinned. Number of seeded berries per cluster became fewer as BMB thinned but percentage of berry setting showed an increasing tendency. Cluster weight, berry weight, berry number per cluster, soluble solids, anthocyanin content were higher in case of around 1cm of diameters of BMB.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.145-149
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• 2004

We investigated the anatomical aspects of vitrification in peace poplar. Comparisons were made with regard to characteristics occurring between hyperhydric and normal shoots in shoot proliferation cultures on MS medium containing 0.2 mg/L BA. Compared with normal plants, hyperhydric plants had thick, curled, and dark green leaves. Hyperhydric stems were thicker and shorter than those of normal stems. When examined under the microscopes, the mesophyll palisade cells of hyperhydric leaves were vacuolated, whereas those of normal leaves contained normal and enriched vacuole with cytoplasm. Generally, the hyperhydric leaves showed poorly developed palisade parenchyma, and revealed irregular and bigger sized intercellular structures in both palisade and spongy parenchyma as well as epidermis cells compare to those of normal leaves. In addition, the hyperhydric leaves had lower stomatal density and bigger sized cell. Vascular tissues of hyperhydic stems were less differentiated because of poorly lignified xylem tissue. The greatly expanded cortical cells and pith appeared to be the main cause of thick stems as compared with normal stems.

• Korean journal of applied entomology
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• v.33 no.2
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• pp.114-121
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• 1994

Population densities of intermediate nymphs and egg saw of Matsucoccus thunbergianae, a major insect pest of Pinus thunbergiona in southern coastal area of Korean peninsula, were est~mated. Tree samples of ca. 10cm D.B.H. were collected from old infestation area and newly invaded area. The numben of plimaly branches per tree were not significantly different by the locality, but those of secondaly and smaller branches were smaller in old infestation area The numbers of intermediate nymphs per tree in old infestation area and in newly invaded area were 10.8 and 13.1 times more than those on the trunk, respectively Approximately between 4, 200 and 208, 500 nymphs per tree were estimated. Men secondaw and smaller bmnch samples collected from the basal part of middle crown height, or from the central or the basal part of lower crown height, the number of samples required for the emr range of 20% were 21 and 11 far 10-20cm and 20-3 crn long branches, respectively. Approx~mately 63.6% of egg sacs of the whole tree were on the trunk. The node/intemode bearing the largest branch had the highest egg sac density; including that, four adjacent nodes/intemodes had ca. 37% of egg saw on the trunk.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.57-57
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• 2018

관상용, 식용 및 약용으로도 이용되는 석죽목 석죽과의 여러해살이풀인 오랑캐장구채는 국내에서는 중부 이북지방의 유용 자생식물로 조경산업에의 이용가치가 크나, 이용성 증대 등을 위한 재배기술은 미흡하다. 지피식물용 재배조건의 구축을 위하여 2017년 7월 31일부터 10월 9일까지 약 10주간 본 연구를 수행하였다. 실험재료로 종자에서 육묘한 유묘를 사용하였으며, 유묘의 소질, 이식조건 및 재배관리에 대한 생육의 영향을 조사하였다. 유묘의 소질로는 162구 트레이에서 cell당 4립씩 파종하여 육묘된 유묘가 초장 및 건물중이 높았고, 특히 4립 파종구는 마디수를 제외한 생육량이 다른 처리구에 비해 유의적으로 큰 차이가 있었다. 경제성을 고려할 때, 상토는 혼합비료(N-P-K) $300-200-200mg{\cdot}L^{-1}$가 첨가된 마사토:피트모스(3:1) 혼용토를 충진한 처리구가 효과적이었다. 또한, 코트비료의 기비처리는 포트당 20알 처리구에서 지하부 생체중이 무거웠으나, 엽면적 등 다른 생육량을 고려할 때 기비하지 않은 처리가 효과적이다. 재배관리에 있어서 차광처리는 습기 등의 환경에 약한 유묘의 특성상 차광하지 않고 배치하는 것이 모든 생육량이 높았다. 이식 후에는 추비처리를 하는 것이 효과적이며, 추비농도는 엽수 등을 고려할 때 $500mg{\cdot}L^{-1}$ hyponex이 적합하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1017-1021
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• 2012

A field experiment was conducted to evaluate effect of water soluble silicate fertilizer (WSS) application on rice plants with respect to comparing with powdery slag-originated silicate fertilizer (PSS) and granular one (GSS). The 30-day seedlings were transplanted on May 10, 2012. The plot size was $25m^2$, and the planting density was 15 hills $m^{-2}$. The standard application level was $2kg\;ha^{-1}$ for WSS, $200kg\;ha^{-1}$ for GSS, $200kg\;ha^{-1}$ for GSS. The application rates were 50 %, 100 %, and 200 % of the standard levels. The soil and plant samples were taken after harvest on September 10. Strength weight of the stem was measured on the center of the 5-cm of the fourth internode. Nutrient contents and yield of grains and were evaluated. The strength weight of the stem was positively correlated with the silicate content of the stem with the highly significant $R^2$ of 0.601. The strength of the stem was satisfactorily enforced by application of 50 % WSS and GSS, and 100 % PSS. Application of 50 % or 100 % of WSS showed little difference in rice yield in comparison with application of 100 % of PSS or GSS. Therefore, application of $20kg\;ha^{-1}$ of WSS would be recommendable for rice cultivation which enforced stem strength, and increased yield of rice.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.580-584
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• 2010

The effect of planting densities on the growth of $Sedum$ $samentosum$ (4 collections) was investigated using nutrient film technique (NFT) with Yamazaki' lettuce nutrient solution (1982) from September 5th to October 24th in non-heating plastic film house. At 40 days, the plant height of 4 collections showed the range of 15.0-18.9 cm, and mean plant height was high the order of $10{\times}10$, $2.5{\times}2.5$, and $5{\times}5cm$. The growth of 'Pohang' and 'Wando' collections was better compared to that of 'Gunsan' and 'Wanju' collections. Number of node, stem diameter, and fresh and dry weight per plant were decreased in higher planting density. Despite the lower fresh weight per plant obtained, the fresh yield per $m^2$ was significantly increased in higher planting density. The mean fresh yield was $14.9kg{\cdot}m^{-2}$ in $2.5{\times}2.5cm$, and 'Pohang' collection showed the highest fresh yield ($17.6kg{\cdot}m^{-2}$). The first optimized harvesting time base on plant height was 30-40 days after NFT culture during autumn season. In eating quality, compression force of stem and bitterness of shoot were decreased in higher planting density. However, the heavy labor demanding high density cutting needs to be improved for hydroponic culture of $S.$ $samentosum$.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.96-104
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• 2010

A comparative study was performed in gnotobiotic and greenhouse conditions to evaluate the effect of exogenous application of indole-3-acetic acid (IAA) and inoculation of Methylobacterium spp. possessing 1-aminocyclopropane-1-carboxylate deaminase (ACCD) and IAA activity on red pepperand tomato seedling growth and development. Application of 1.0 ${\mu}g\;mL^{-1}$ IAA positively influenced root growth while high concentrations (>10.0 ${\mu}g\;mL^{-1}$) suppressed root growth of red pepper and tomato under gnotobiotic condition. On the other hand, inoculation of Methylobacterium strains with ACCD activity and IAA or without IAA enhanced root growth in both plants. Similarly, under greenhouse condition the inoculation of Methylobacterium sp. with ACCD activity and IAA enhanced plant fitness recorded as average nodal length and specific leaf weight (SLW) but the effect is comparable with the application of low concentrations of IAA. Seedling length was significantly increased by Methylobacterium strains while total biomass was enhanced by Methylobacterium spp. and exogenous applications of < 10.0 ${\mu}g\;mL^{-1}$ IAA. High concentrations of IAA retard biomass accumulation in red pepper and tomato. These results confirm that bacterial strains with plant growth promoting characters such as IAA and ACCD have characteristic effects on different aspects of growth of red pepper and tomato seedlings which is comparable or better than exogenous applications of synthetic IAA.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.85-94
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• 2015

The weed flora in the mulberry fields were investigated in Suwon, Jeonju, and Buan in May, July, and September of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds in the Korean mulberry fields. The survey was conducted in 53 regions, covering approximately $145,925m^2$. Altogether 153 weed species of 37 families were identified, of which 68 were annual, 39 species were biennial and 46 were perennial. The dominance was the highest with Digitaria ciliaris followed by Erigeron annuus, Chenopodium album, Echinochloa crus-galli var.crus-galli, Acalypha australis, Commelina communis etc. Exotic weeds presented 44 species with 28.8% of a total presence, of which Erigeron annuus was the highest, followed by Chenopodium album, Phytolacca americana, Conyza canadensis, Oxalis corymbosa etc. Especially, we should aware Senecio vulgaris, not controlled with glufosinate ammonium SL in the Korean mulberry fields because it was known as atrazine resistance in US, Canada, Germany etc. In the PCA plot, weeds presented in the mulberry fields were divided into two groups, Eclipta prostrata community and Stellaria aquatic community and weed flora of Suwon and Buan were different due to those only presented in Suwon.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.39-43
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• 2004

This study was conducted to determine the optimum planting distance under rain-shielding condition for improving quality and productivity of squash by staking cultivation. The squashes were grown by 3 planting distances, such as 120${\times}$30, 120${\times}$40 and 120${\times}$50 cm during 3 months under non heat condition. The vine length, fresh weight and leaf area were reduced as planting distance was decreased until main branch was pinching. The first female flowering day and first fruit setting nodes were not different among treatments. The first fruit length and second fruit weight were increased in 120${\times}$50 cm planting distance, but the soluble solid contents were not different among treatments. In 120${\times}$30 cm plant distance, total yield was highest (6,510 kg/10a), but marketable yie이 was lowest. When the planting distance was between 120${\times}$40 cm and 120${\times}$50 cm, the marketable rate was similar (over 98%), but marketable yield was highest in 120${\times}$40 cm planting distance (5,012 kg/10a). The results of this study indicated that the optimum planting distance of staking cultivation in squash seemed to be 120${\times}$40cm.