• Journal of Korea Foresty Energy
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• v.7 no.1
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• pp.22-27
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• 1987

Above ground biomass production of one-year-old hybrid poplars was investigated to select the best clones which are suitable for short rotation forestry. The results were as follows: 1. Average dry weight of Populus alba X P. glandulosa Fl clones was 2.86 for stem,0.41 for branches 0.70 for leaves and 3.97 t/ha for total. and the ratios of green weight to dry weight were 0.47 for stem,0.36 for branches,0.31 for leaves and 0.42 for total. Dry weight of Populus nigra X P. maximowiczii Fl clones was 1.48 for stem, 0.54 for branches.0.71 for loaves and 2.73t/ha for total, and the ratios of green weight to dry weight were 0.42 for stem. 0.37 for branches, 0.28 for leaves and 0.36 for total. 2. Biomass production (green and dry weight)of Populus alba X P. glandulosa F1 clones can be predicted by diameter measurement only, but biomass production of Populus nigra X P. maximowiczii F1 clones can not be predicted by any of investigated characteristics. 3. Dry weight distribution of pepulus alba X P. glandulosa Fl clones were 73$\%$ for stem, 10$\%$ for branches and 17$\%$ for leaves, and dry weight distribution of P. Populus nigra X P. maximowiczii F1 clones were 54$\%$ for stem, 20$\%$ for branches and 26$\%$ for leaves.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.82-82
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• 2019

황해쑥(Artemisia argyi Lev. et. Vnt)은 국화과의 다년생 초본 식물로서 쑥, 산쑥과 함께 건조한 것이 애엽이라는 생약재로 쓰이며 2016년 기준 전국적으로 81 ha에서 871톤이 생산되고 있다. 주요 유효성분으로 Eupatilin, Jaceosidin 등이 있으며 위궤양에 효과가 있다고 알려져 있어 최근에는 스티렌정 등 신약원료로 각광 받고 있다. 황해쑥은 종자번식 뿐만 아니라 포복경을 이용한 영양번식이 가능하며 현재까지 '섬애' 등 1품종이 개발되어 있으나 농가와 산업체가 요구하고 있는 수량성 또는 Eupatilin 등 성분함량이 높은 품종개발이 필요하다. 국내 연구 결과를 보면 대부분 년 1회 수확을 기준으로 연구되어 왔으나 실제로는 년 2회 수확하는 경우가 더 많다. 따라서 본 실험에서는 년 1회 뿐만 아니라 년 2회로도 수확하여 조사하였다. 시험재료는 AA1801 등 7계통 이며, 시비량은 10 a 당 질소 15.3 kg 인산 20 kg 가리 5 kg이고, 흑색 비닐을 피복한 후 조간 30 cm 주간 15 cm로 하였다. 시험구배치는 난괴법 3반복으로 하였으며 포복경을 5 cm로 잘라 4월 19일에 정식하였다. 1회 수확 시에는 8월 12일, 2회 수확 시에는 6월 17일, 9월 19일에 수확 하였다. 년 1회 수확 시 계통 별 생육특성을 보면, 초장은 202.4~231.5 cm로 평균 213.6 cm 였으며 경경은 10~12.14 mm로 평균 10.9 mm 였다. 분지수는 32.6~37.3개로 평균 35.2개 였으며 엽병장, 엽장, 엽폭은 2.4~4.2 cm, 9.3~12 cm 9.2~12.2 cm로 평균 3.3 cm, 10.7 cm 그리고 10.9 cm 였다. 전초의 생중량과 건중량은 각각 4.9~6.9 kg, 1.8~2.7 kg로 평균 5.5 kg, 2.1 kg 이였다. 특히 AA1902는 다른 계통에 비해 분지수는 적었으나 초장이 크고 경경이 굵었으며 생중량과 건중량도 가장 무거웠다. 년 2회 수확 시 전초의 생중량과 건중량은 각각 5.1~6.2 kg, 1.7~2.0 kg로 평균 5.6 kg, 1.8 kg 이였다. 수량성으로 봤을때는 AA1902는 1회 수확에 적합하며 AA1801, AA1802는 2회 수확 시 생중량과 건중량이 무거웠다. 또한 AA1903의 경우 수확 회수와 상관없이 수량성이 높은 계통으로 판단되었다. 본 자료는 황해쑥 품종육성의 기초자료로 활용하고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.115-121
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• 2021

Human's landing strategies have been explained through lower extremity kinetics in various conditions. However, how lower extremity kinetics respond when the two conditions between a load and landing height are combined is not yet understood. To achieve the purpose of this study, a total of 20 men and women were subjected to drop landing according to a load(No load, 10%, 20%, 30% of the body weight) at various landing heights(0.3 m, 0.4 m, 0.5 m). As a result of the study, the main effect of a load was not statistically significant in all variables. But increasing of the landing heights showed more flexion angle which was statistically significant in knee joint. In addition, as the landing height increased, the medial-lateral, anterior-posterior, vertical force, and loading rate increased, while time to peak vertical force decreased which was statistically significant. Thus, humans can successfully perform the landing motion even if the load is changed at various heights. However, it reacted more sensitively to the change in landing height than that load condition. The landing height can be prepared for recognition and shock absorption through visual information, but the weight level is difficult for the body to perceive and explains why it is more difficult to apply it to the landing strategy mechanism for shock absorption.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.109-116
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• 2023

The purpose of this study was to investigate the influence of gender and load carriage difference on the lower extremity kinetics during stair descent. Ten healthy males and 10 healthy females were recruited (n=20). In the Maximum resultant velocity, it showed more velocity was decreased with difference by the change of gender (males>females) and load carriage (30%, 20%, 10%> 10%). And, resultant velocity showed interaction between gender and a load (load>gender). Main effect by gender during stair descent showed leg length was decreased in females than that of males at initial contact phase. Also, main effect by gender during stair descent showed more hip, knee flexed and plantar flexion of ankle joint in females than that of males. In the kinetics variables, main effect by gender during stair descent showed more higher reaction force of medial-lateral direction, and leg stiffness in males than that of females. We found that females successfully accommodated a load during stair descent by decreasing the range of motion of the hip joint angle and resultant velocity of movement. Males, on the other hand, require greater medial-lateral, vertical reaction force, and leg stiffness to accommodate a load, and control of momentum.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2477-2479
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• 2003

본 연구에서는 타이어의 중량 불균일 측정을 위한 메카니즘의 모델링 및 분석을 통해 로드셀에 의해 샘플링된 신호를 해석하여 불균일량을 측정하는 방법을 제안한다. 진동역학적인 모델을 근거로 신호의 변환과 영향계수의 산출을 통해 정확한 불균형량 측정을 가능하게 하였다.

• 월간 기계설비
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• no.9 s.206
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• pp.26-26
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• 2007

석면함유제품이 암 및 각종질병을 유발함에 따라 2006년 9월 30일 이 제품의 사용금지를 골자로 한 고시가 제정된 데 이어 지난 7월 2일 개정 되었다. 이 고시에는 '누구든지 함유된 석면의 중량이 제품 중량의 0.1퍼센트를 초과하는 제품을 사용할 수 없다'는 내용을 담고 있으며 2008년 1월 1일부터 시행될 예정이다.

• 월간산업보건
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• s.385
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• pp.32-35
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• 2020

제조현장에서 작업자들이 근골격계질환 및 중량물 관련 사고를 겪는 일이 많습니다. 인천산업보건센터 양승태 차장은 지난 15년 간 보다 안전한 작업환경을 만들기 위해 수많은 현장을 방문했으며, 이 과정에서 고찰한 중량물 사고에 대한 연구가 국제 학술지에 수차례 게재되었습니다. 양승태 차장의 인간공학적 관점의 연구와 사고 예방을 위한 솔루션을 들어보았습니다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.1
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• pp.29-35
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• 2015

The concept design of a riser for Ocean Thermal Energy Conversion in 10 MW is proposed and its dynamic behaviour characteristics is analyzed with numerical method. A riser pipe with a hollow along its thickness in the cross-section to increase the effective modulus of its cross-section is designed considering the manufacture. The riser pipe without hollows along its thickness needs a lumped weight at the bottom end of a riser in order to keep its vertical hanging configuration from large buoyancy and the strong current. The riser is designed to control its density by inserting materials in high or low density into a hollow. The dynamic behaviour characteristics of the two designed risers is evaluated with the developed numerical analysis tool. The combined stress of the riser with a lumped weight is showed to be dominated by weight of a lumped mass. The riser with no hollow shows large combined stress near sea surface by strong current. Local structural analysis for the cross-section of a hollow riser is needed in detail.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.184-191
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• 2011

Preliminary design of a mooring system for a floating wave energy converter(WEC) is performed. A mooring line is designed to consist of two parts; the one is a chain in heavy weight laid on the seabed and linked to an anchor on the seabed and the other is a light weight chain suspended at a floater. A high weight chain laid on the seabed can contribute to mitigate dynamic energy propagated from top oscillation and decrease anchor weight and volume. Through a low weight chain suspended between a floater and seabed the WEC's function to produce energy from wave can be affected in minimum by the motion of a chain. The static and dynamic analyses for the designed mooring system were carried out to evaluate WEC system's safety. The present study shows that the designed gravity anchor moves horizontally due to the tension exerted on the anchor in the severe ocean environmental condition. The present mooring system should be redesigned to satisfy the safety requirements. The present study will be useful to predict the safety of the mooring system under ocean environment.

• Journal of the Korea Concrete Institute
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• v.28 no.4
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• pp.435-444
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• 2016

In Korea, approximately 48% of all households live in apartments, which are a form of multi-unit dwellings, and this figure increases up to 58%, when row houses and multiplex houses are included. As such, majority of the population reside in multi-unit dwellings where they are exposed to the problem of floor impact noise that can cause disputes and conflicts. Accordingly, this study was conducted to manufacture a high-weight, high-stiffness foamed concrete in order to develop a technology to reduce the floor impact noise. For the purpose of deriving the optimum mixing ratio for the foamed concrete that best reduces the floor impact noise, the amounts of the foaming agent, lightweight aggregate and binder were varied accordingly. Also, the target characteristics of the concrete to be developed included density of over $0.7t/m^3$, compressive strength of over $2.0N/mm^2$ and thermal conductivity of under 0.19 W/mK. The results of the experiment showed that the fluidity was very excellent at over 190 mm, regardless of the type and input amount of foaming agent and lightweight aggregate. The density and compressive strength measurements showed that the target density and compressive strength were satisfied in the specimen with 50% foam mixing ratio for foamed concrete and in all of the mixtures for the lightweight aggregate foamed concrete. In addition, the thermal conductivity measurements showed that the target thermal conductivity was satisfied in all of the foamed concrete specimens, except for VS50, in the 25% replacement ratio case for Type A aggregate, and all of the mixtures for Type B aggregate.