• The Korean Journal of Ecology
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• 제22권2호
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• pp.79-83
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• 1999

Phytotoxic effects of ozone and ethylenediurea (EDU) on soybean (Glycine max) and spinach (Spinacia oleracea) were observed by using open-top field chamber system (OTC). Gas exchange rates (photosynthesis. stomatal conductance and transpiration rates) of soybean plants were decreased by 20% to 30% by ambient ozone and resulted in 30% reduction of seed yields. In OTC. ambient ozone and 0.12 $\mu$l/l $O_3$ decreased gas exchange rates of spinach by 25% to 40% and by 50%. respectively. The protective effect of EDU against ozone induced injury was obtained at 100 mg/l on soybean. and at 250 mg/l on spinach, respectively. The excessive application of EDU. however. inhibited photosynthesis. transpiration. and stomatal conductance without any specific visible damage.

• Corrosion Science and Technology
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• 제19권3호
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• pp.115-121
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• 2020

In this study, erosion tests and erosion-corrosion tests of Al5083-H321 aluminum alloy were conducted at various flow rates in seawater. The erosion tests were conducted at a flow rate of 0 to 20 m/s, and erosion-corrosion tests were performed by potentiodynamic polarization method at the same flow rate. Characteristic evaluation after the erosion test was conducted by surface analysis. Characteristic evaluation after the erosion-corrosion test was performed by Tafel extrapolation and surface analysis. The results of the surface analysis after the erosion test showed that surface damage tended to increase as the flow rate increased. In particular, intermetallic particles were separated due to the breakdown of the oxide film at 10 m/s or more. In the erosion-corrosion test, the corrosion current density increased as the flow rate increased. Additionally, the surface analysis showed that surface damage occurred in a vortex shape and the width of the surface damage tended to increase as the flow rate increased. Moreover, damage at 0 m/s, proceeded in a depth direction due to the growth of pitting corrosion, and the damaged area tended to increase due to acceleration of the intermetallic particle loss by the fluid impact.

• Journal of Nutrition and Health
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• 제33권6호
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• pp.625-631
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• 2000

The purpose of this study was to investigate the effects of vitamin E on the oxidative damage and glomerular filteration rates(GFR) of kidney in streptozotocin(STZ) induced diabetic rats. Sprague-Dawley male rats weihing 100$\pm$10gm were randomly assigned to one normal and three STZ-induced diabetic groups which were subdivided into vitamin E free diet(DM-0E group)40mg vitamin E per kg diet(DM-40E group) and 400mg vitamin E per kg diet (DM-400E group), Vitamin E level of normal group was 40mg per kg diet. diabetes was experimentally induced by intravenous injection of 55mg/kg of body weight of STZ in citrate buffer(pH 4.3) after 4 weeks feeding of experimental diets. Animals were sacrificed at the 6th day of diabetic states. Activities of xanthine oxidase(XOD) in DM-0E DM-40 and DM-400E groups were significantly increased by 133%, 110%, and 74% respectively compared to normal group. The contents of microsomal superoxide radical(O2) in kidney were 106% and 119% higher of DM-0E and DM-40E groups than normal group respectively but that of DM-400E group was similar to normal group. The level of urnary microalbumin in DM-0E group was increased as 5 times much as normal group at the 6th day. Those of DM-40E and DM-400E groups were decreased to 16% and 36% respectively compared to DM-0E group. The content of urinary $\beta$2-microglobulin in DM-0E DM-40E and DM-400E group were increased by 268%, 181% and 163% respectively compared to normal group. GFR in DM-0E and DM-40E were significantly increased but was nor significantly different from DM-400E groups compared to normal group. In conclusion the supplementation of dietary vitamin E reduced peroxidative damage of renal glomerular and renal dysfunction in diabetic rats.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.199-199
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• 2017

This study investigated the aspects of damage due to low temperature treatment in order to establish the damage criterion according to low temperature invasion during regeneration period in wheat after regeneration period in the early spring. We cultivated wheat cultivar 'Geumgang' in Wagner pots and treated them with three types of low temperature, and the gradual temperature change program was set in a low temperature incubator for 12.5 h per day for 5 days during the night time when the length of young spikes was about 1 mm. All treatments except for the control were treated in 5 steps for each temperature. Treatment 1 was treated at the lowest temperature $-5^{\circ}C$ for 5 h, treatment 2 for 7 h at $-5^{\circ}C$, and treatment 3 for 9 h at $-5^{\circ}C$. The most common type of damage was partial infertility, and there were some discolored spikes. The damage rate of wheat spikes treated at $-5^{\circ}C$ for 9 h was the highest, while the damage rates of wheat sprouts treated at 5h and 7h were not different from each other. It was found that the damage of wheat spikes exposed to low temperatures for a long time was large. It is necessary to investigate the aspects of spike damage by duration days of low temperature.

• 한국농림기상학회지
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• 제7권4호
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• pp.258-264
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• 2005

The objectives of this study were to study 1) emergence of pine bark beetles, 2) larval density in residual timber on Idlest land by each felling season, and 3) the secondary damage rates in the tended forest. Pine forest land which had undergone tending had a higher secondary damage ratio $(59.6\%)$ by pine bark beetles than forest land that was not tended $(2.8\%)$. The number of escape holes averaged 11.3 0.31 per $250 cm^2$ on the bark of leaf trees in the tended forest. The number of escape holes was higher in the Jinju site than in the Hamyang site. The larval habitat density of pine bark beetles as compared with each felling period was higher after mid-October than in forests tended early in October. Thus, forests should be tended before early October in order to prevent secondary damage from pine bark beetles. Secondary damage in the tended forest was higher in the upper part $(75.5\%)$ of the tree crown than in the lower part $(49.2\%)$. The damage was higher in terminal shoots $(80\%)$ than in lateral shoots $(48\%)$. Therefore, secondary damage by pine bark beetles can cause deterioration of the elongation growth of the forest trees. In conclusion, if by-products of tended pine forest forests are neglected, they will be utilized as a propagation site for pine bark beetles (Blastophagus piniperda L). The propagated adults will damage the tender shoots of the leaf trees and thus seriously limittheir elongation.

• 한국응용곤충학회지
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• 제50권4호
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• pp.379-382
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• 2011

밤나무 재배지에서 밤의 종실에 발생하여 알밤을 가해하는 복숭아명나방(Dichocrocis punctiferalis) 을 선정된 조사지역에서 1995년부터 2010년까지 16년 동안 년도별, 지역별, 숙기별로 조사한 결과는 다음과 같다. 년도별 피해율은 1998년이 34.5%로 가장 높았고, 2000년이 17.9%로 가장 낮았다. 년도별 피해율의 패턴은 3년의 반복 주기로 변화되었다. 복숭아명나방의 피해율과 강우량과는 부의 상관($-0.6261^*$)이었고, 온도의 상관은 정의 상관($0.5826^*$)이었다. 조사 지역의 전체 평균 피해율은 22.2%이었고, 조사지역 중에서 합천지역이 27.0%로서 가장 높았고, 함양지역이 15.0%로서 가장 낮았다. 밤나무 성숙기별 피해율은 조생종인 단택품종이 26.1%로서 피해율이 가장 높았고, 중생종과 만생종인 축파, 은기품종의 피해율이 각각 19.3%, 21.1%로 같은 수준이었다.

• 한국해양공학회지
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• 제4권2호
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• pp.15-21
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• 1990

This study focuses the mechanical deformation response predicted by the plasticity model for polycrystalline ice. To describe various deformation characteristics, ice is idealized as a perfectly plastic material using an asymptotic exponential failure criterion. This criterion is suite for describing materials which exhibit brittle deformation at low hydrostatic pressure and ductile deformation at high hydrostatic pressure. The results are compared to those of continuum damage mechanics model. Plasticity model shows good agreement with damage model and experimental results for high confining pressures even at high strain-rates which is usually considered as a brittle condition under uniaxial compression.

• 한국해양공학회지
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• 제4권2호
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• pp.165-165
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• 1990

This study focuses the mechanical deformation response predicted by the plasticity model for polycrystalline ice. To describe various deformation characteristics, ice is idealized as a perfectly plastic material using an asymptotic exponential failure criterion. This criterion is suite for describing materials which exhibit brittle deformation at low hydrostatic pressure and ductile deformation at high hydrostatic pressure. The results are compared to those of continuum damage mechanics model. Plasticity model shows good agreement with damage model and experimental results for high confining pressures even at high strain-rates which is usually considered as a brittle condition under uniaxial compression.

• The Korean Journal of Ecology
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• 제21권2호
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• pp.125-131
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• 1998

Histological damage and growth inhibition of Pinus densiflora were analysed in different areas around the Metropolitan area of Seoul urban (heavily polluted), suburban (lightly polluted), and rural(unpolluted) areas. Soil properties of each area were also investigated. Contact angles of water droplet on needle leaves growing in polluted areas were lower than that in unpolluted area. Transpiration rates of needle leaves growing in polluted areas were more rapid than that in unpolluted area. These results represented that needle leaves growing in polluted areas were more susceptible to water deficit than that growing in unpolluted area was. Growths of annual ring of Pinus densiflora growing in polluted areas were lower than that in unpolluted area. On the other hand, soil pH in polluted areas was lower than that in unpolluted area. That is, the former was more acidified than that the latter was. Ca and Mg contents in polluted areas were lower than that in unpolluted area, while Al contents in polluted areas were higher than that in unpolluted area. These soil properties revealed that the effects of acid precipitates in urban and suburban areas were severer than that in rural area.

• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1252-1263
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• 2016

This paper presents a numerical method to simulate ductile tearing in cracked components under high strain rates using finite element damage analysis. The strain rate dependence on tensile properties and multiaxial fracture strain is characterized by the model developed by Johnson and Cook. The damage model is then defined based on the ductility exhaustion concept using the strain rate dependent multiaxial fracture strain concept. The proposed model is applied to simulate previously published three cracked pipe bending test results under two different test speed conditions. Simulated results show overall good agreement with experimental results.