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        검색결과 938

        342.
        2010.12 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the alleviative effects of a nude pack containing black tea water extract (NPBT) on inflammation and skin barrier damage in hairless mice. Skin inflammation and skin barrier damage were induced by UVB irradiation to the backs of hairless mice for five weeks. And, at the same time, saline (C), NPBT (1%: E1, 2%: E2), and 0.01% retinoic acid diluted with polyethylene glycol (PC) were applied topically twice per day, five days per week, for a period of five weeks. The skin erythema indices of the E1 and E2 groups were significantly lower (p<0.05) than those of the C group through one week after the beginning of the experiment. Meanwhile, water contents of the E1 and E2 groups were significantly higher (p<0.05) than those of the C group through two weeks after the beginning of the experiment. Remarkable thickening of epidermis and dermis was observed in the C group, compared with the PC, E1, or E2 groups. In the C group, infiltration of many inflammatory cells, including neutrophils and lymphocytes, was observed in dermis and a large number of mast cells were observed in dermis and hypodermis, and the degree of degranulation was remarkable. However, these phenomena were alleviated in the PC, E1, and E2 groups. Therefore, NPBT could have considerable inhibitory efficacy on inflammation and skin barrier damage induced by UVB irradiation.
        4,000원
        343.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the relationship of larval density of tobacco cutworm, Spodoptera litura (Fabricius) to damage in greenhouse sweet pepper. Laboratory experiments, cage experiments by artificial release and field investigation were carried out in 2008. The leaf consumption rate increased greatly with larval development. The damaged leaves had several round or oval shape holes on the surface or lost certain parts of them, and the fruit damaged had a conspicuous hole on the surface or scar marks around the calyx. In the field investigation, fruit damage was highly correlated with larval densities and reached 3.5% damage at maximum. Cage experiments showed that numbers of non-marketable fruit increased as increasing larval densities released. The larval density at two weeks before harvest had a high relationship with the percentage of damaged-fruit at harvest. Corresponding larval density caused 1, 3, 5% of damaged-fruit was 0.2, 0.5, 0.8 larvae per plant, respectively.
        4,000원
        344.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The striped fruit fly, Bactrocera scutellata (Diptera: Tephritidae), is one of the most important pests in Cucurbitaceae plants. Among 6 attractants for B. scutellata used, Cue-lure was shown better effect than the others. Newly emerged adult of B. scutellata had been occurred early June of the year tested. There were two peaks of occurrences of B. scutellata, one was from mid-July to early August and the other was early September suggesting that B. scutellata has two generation a year. The larva of B. scutellata damaging the female flower and stem of the pumpkin was found for the frist time on Korea. The blossoms were damaged and fallen by B. scutellata which were 53.8% of male flower and 30.7% of female flower in the 6 pumpkins. The pumpkin flowers were damaged 51.9% by B. scutellata. Especially the pumpkin flowers damaged were shown 72.7% (1015/1397 individuals) from August to September. The larva of B. scutellata was found from the Trichosanthes kirilowii on 24 June 2009 in Jinan-gun Jeollabuk-do.
        4,000원
        345.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        각종 유전독성학적 물질로 인한 생물체내의 영향을 평가해보기 위해 E. fetida를 대상으로 본 연구를 수행하였다. 염화수은에 대한 DNA 손상을 알아보는 실험에서는 노출 시간에 상관없이 노출 농도에 비례한 유전자의 손상이 나타났다. 방사선이 지렁이의 DNA 손상에 미치는 영향을 알아본 실험에서도 역시 방사선 총 선량의 증가에 따라 DNA 손상이 증가하는 경향을 보였다. 염화수은에 48시간 동안 노출시키고 방사선을 조사한 지렁이의 세포를 comet as
        4,000원
        346.
        2010.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have studied methods to save Si source during the fabrication process of crystalline Si solar cells. One way is to use a thin silicon wafer substrate. As the thickness of the wafers is reduced, mechanical fractures of the substrate increase with the mechanical handling of the thin wafers. It is expected that the mechanical fractures lead to a dropping of yield in the solar cell process. In this study, the mechanical properties of 220-micrometer-solar grade Cz p-type monocrystalline Si wafers were investigated by varying saw-damage etching conditions in order to improve the flexural strength of ultra-thin monocrystalline Si solar cells. Potassium hydroxide (KOH) solution and tetramethyl ammonium hydroxide (TMAH) solution were used as etching solutions. Etching processes were operated with a varying of the ratio of KOH and TMAH solutions in different temperature conditions. After saw-damage etching, wafers were cleaned with a modified RCA cleaning method for ten minutes. Each sample was divided into 42 pieces using an automatic dicing saw machine. The surface morphologies were investigated by scanning electron microscopy and 3D optical microscopy. The thickness distribution was measured by micrometer. The strength distribution was measured with a 4-point-bending tester. As a result, TMAH solution at 90˚C showed the best performance for flexural strength.
        4,000원
        348.
        2010.11 구독 인증기관 무료, 개인회원 유료
        유류에 의한 해양오염은 해양환경에 심각한 영향을 미치기 때문에 사전에 방지되어야 함이 최선이다. 하지만 일단 사고가 발생한 경우는 신속한 방제조치와 아울러 피해자에 대한 신속하고도 적정한 손해배상이 이루어져야 한다. 이는 피해 국민들의 생존권 보호차원에서도 구체적으로 실현되어야 할 과제이다. 해양사고에 의한 유류오염 피해가 발생할 경우 가장 큰 영향을 받는 것는 해양 생태계 파괴에 따른 어업 피해라고 할 수 있는데, 지금까지 국내 유류오염사고에 대한 국제기금의 어업피해 보상율은 피해 청구액 대비 약 10~30%로 인접국이나 유럽 국가에 비해 현저히 낮은 수준이다. 이 연구에서는 최근 허베이 스피리트호 사고 피해보상 진행과정에서 나타난 문제점을 분석하여 국내 해양 유류오염사고 손해배상율 제고방안을 제시한다.
        3,000원
        349.
        2010.10 구독 인증기관·개인회원 무료
        The purpose of this work was to study the effects of electron beam irradiation on development and reproduction and evaluate the DNA damage in Plutella xylostella. Adults and pupae of P. xylostella were irradiated with 30, 50 and 100 Gy electron beam. Hatchability and fecundity of adults declined as increased irradiation doses. When pupae were irradiated with 100 Gy, fecundity of emerged adults significantly decreased and no eggs hatched. However, the adults longevity and emergence of pupae did not change. Assessment of DNA damage in cells obtained from adults and pupae of P. xylostella was carried out using single-cell electrophoresis (comet assay). Electron beam-radiated adults and pupae showed that tail length and percentage of DNA damage at all the doses were significantly larger than the control batch. Our results suggest that electron beam induces sterility through the DNA damage and this technique could contribute to analytical identification of an effective disinfestation and quarantine treatment.
        350.
        2010.10 구독 인증기관·개인회원 무료
        Field survey were conducted in to evaluate the insect damage to growing Lemonbalm(Melissa officinalis). Lemaonbalm, belonging to the Lamiaceae family, is a smelling perennial shurb which is possible to grow in Korea. To date, there has been minimal research regarding plant culture, pest insect occurrence and management research about herbal plants in Korea. Meanwhile, it grows for processed food and cosmetics in Jellabukdo, and necessity to pest management is on the rise. Chrysolina exanthematica(Coleoptera: Chrysomelidae) was realized not pest but general insect in Korea. But, in this survey, it is found to pest about lemonbalm. Damage period was concentrated in April. Rest period was decreased in density. At size of Chrysolina exanthematica, larva is 7.0*3.6mm, pupa is 8.3*5.3mm, and adult is 9.7*6.7mm. In farm surveying about Chrysolina exanthematica host preference of 5 species herb plants, Lemonbalm has great preference but, Oregano has no preference. Surveying leaf damage about 6 species in Lamiaceae family in lab., Lemonbalm belonging to Melissa genus has great damage, Some species in Mentha genus have little damage. And, Oregano in Origanum genus no damage. In Growth characteristics of healthy and damage plant, plant length on damage plant is decreased 41.3%, number of tiller is decreased 67%. Fresh and dry plant weight of damaged plant is decreased 66.7%, 64.2% compared with healthy plant. Because damage of insect can influence on plant main contitutents, we analysed the constitutent parts of extracts from supercritical fluid extraction system using gas chromatography/mass spectrometer.
        351.
        2010.10 구독 인증기관·개인회원 무료
        Nokona regalis (Butler) and Toleria romanovi (Leech) (Lepidoptera: Sesiidae) are economically important pests of grape in northeast Asia. We compared the overwintering, damage and seasonal flight activities of these two species in Korean vineyards. Mature larvae of N. regalis overwintered in the infested shoots of grape, while T. romanovi overwintered as mature larvae enclosed within a cocoon in the soil. Larvae of the former species fed primarily in grape shoots (97.2%), whereas larvae of the latter species burrowed into main trunks (57.4%) and branches (40.4%), causing significant damage and frequent mortality. The seasonal fluctuation of male catches was monitored with pheromone traps in 2010. Male moths of N. regalis were present from late May until middle June, and peak abundance occurred in early June. T. romanovi males were trapped from early June to early August with peak catch in middle July in Suwon.
        352.
        2010.10 구독 인증기관·개인회원 무료
        In this study, we examined the spatial dependence and association of Ambrosia beetle, Platypus koryoensis, which is the vector of oak wilt disease caused by Rafaelea sp. using two geostatistical methods. Two adjacent sampling plots were selected and named as "Sector A" and "Sector B". Sector A area was 63 ha and Sector B area was 420 ha, respectively. We arbitrarily separated each sampling plot by 50m×50m grids. Sector A and B were separated by 19×15 and 43×41 grids, respectively. The oak wilt disease damage level of tree was classified by amount of frass of Ambrosia beetle near target oak tree as follows: Lost tree (LT), Severe damage (SD), Intermediate damage (ID), and Light damage (LD). Number of each damage level of oak tree was counted and recorded in each sampling grid. Spatial dependence and association of oak wilt damage was analyzed and compared using mathematical variogram models and spatial analysis by distance indices (SADIE). Variogram model ranges were 179~368m in Sector A and 634~1073m in Sector B, respectively. The damage levels of all trees in each sector were indicated as aggregated distribution by aggregation indices of SADIE (Ia > 1). Each damage level pair had strong association in the consecutive orders than in any random order based on the results of SADIE association test. The spatial dependence and association of oak wilt damage levels presented here provide the baseline information necessary to understand and manage oak wilt disease in Korea.
        355.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with advanced composite materials (ACM) are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a ACM-strengthened RC wall structure.
        4,000원
        356.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dispersion of the functionalized multiwalled nanotubes (MWNT) in the polyurethane (PU) matrix and DC conductivity of the MWNT/PU composites are investigated with the oxidation conditions, the kind of surfactants and their content. First, the most optimal surfactant type and its critical micelle concentration in the MWNT suspension are determined as a cationic surfactant, benzalkonium chloride (BKC) of 0.6 wt.% to the MWNT content from DEA and FESEM results. All the MWNT oxidized under several conditions are negatively charged and functionalized with carboxylic group, whereas the degree of damage is different from oxidation conditions. In addition, each MWNT/PU composite derived from several oxidation conditions shows different DC conductivity at a characteristic MWNT content. It is found that in order to enhance DC conductivity of the polymeric composites containing the oxidized MWNT the better dispersion of MWNT should be obtained by effective functionalities and surfactant adsorption with preserving the intrinsic geometry of pristine MWNT.
        4,000원
        357.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Gas turbines for power generating operate in a very high temperature condition and use natural gas for fuel. For this reason, many cases of damage happen at hot gas parts which are severely affected by high temperature gas and many cases of explosion occur by fuel gas. So a lot of efforts should be made to prevent hot gas parts damage and gas explosion accidents. Though there are many damage cases and explosion accidents, it is very difficult to find out the root causes of hot gas parts damage caused by gas explosion due to gas leakage in the heat exchanger for air cooling and gas heating. To prevent gas turbine from damage caused by gas explosion, removal of leakage gas from gas turbine is inevitably required before firing the gas turbine and installing alarm systems is also required for detecting gas leakage at stop valve to turbine while shut down.
        4,000원
        358.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근에 폭설로 인한 온실의 붕괴가 빈번해져서 농가의 피해가 증가되고 있다. 히지만 폭설로 인한 온실의 붕괴를 막기 위한 정확한 구조해석에 대한 연구가 미약하여 매년 농가의 피해는 되풀이 되고 있다. 기존 온실의 구조해석 방법은 미소변위에 기초한 선형탄성해석으로 이루어지고 있다. 그러나 실제 온실의 강성은 건축 구조물의 강성에 비해 상당히 약하지만 하중은 폭설에 의해 상대적으로 크게 작용하여 변형이 크게 발생하고 구조물의 기하학적 형태가 변하므로 변형률-변위 관계가 비선형 거동을 한다. 본 연구에서는 폭설에 따른 온실의 붕괴를 막기 위하여 농가에서 많이 사용되는 농가 지도형 G형 단동온실과 농가보급형인 1-2W 기본형 연동온실에 대해 시간에 따른 하중단계별 기하학적 비선형 효과를 고려하여 온실의 정확한 거동분석과 구조적 안전성을 평가하는데 대변위해석 방법을 제시하고자한다.
        4,000원
        359.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        비정형 평면을 가진 건물의 추가적인 손상의 원인이 되는 비틀림과 비정형성의 척도인 편심과의 관계에 대한 많은 연구들이 진행되어 왔으나 손상도와 편심의 직접적인 관계에 대한 연구는 수행된 적이 거의 없다. 본 연구에서는 비정형 평면을 가진 건물의 복잡한 지진 응답에 적용할 수 있는 3차원 손상도 계수를 이용하여 건물의 손상도와 편심에 대한 정량적인 관계를 분석하였다. 이를 통해 건물의 편심이 커지면 최대변위는 줄어들지만 비틀림 거동이 증가하여, 손상의 집중으로 인해 전반적인 손상도 계수가 증가함이 관찰되었다. 또한, 2차원 주기가 비슷한 경우에는, 건물의 길이가 최대변위와 최대 비틀림에 미치는 영향이 작으며 이로 인해 전체 손상도 계수에도 그 영향이 미미한 것으로 관찰되었다. 해석 결과를 바탕으로 중약진 지역에서 편심의 크기가 10%, 20%, 30%인 단층 건물은 편심이 없는 건물에 비해서 각각 평균 3~5%, 13~18%, 33~47% 정도의 손상도 증가가 있을 것으로 분석하였다. 이와 같은 편심-손상도 관계는비정형 평면을 가진 건물의 내진 설계에 있어서 기본 구조 계획 수립과 내진 성능 평가에 유용한 자료가 될 것으로 생각된다.
        4,000원
        360.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        현행의 내진설계의 성능목표는 인명피해를 최소화하기 위한 구조물의 붕괴방지에 있으며 기존구조물의 내진보강도 이를 만족하도록 수행되고 있다. 그러나, 최근의 해외 지진피해사례를 살펴보면 큰 지진에서도 이러한 내진성능목표는 비교적 잘 달성되었지만 엄청난 경제적 손실이 동반되어 새로운 문제점으로 제기되고 있다. 이러한 큰 경제적 손실을 줄이기 위해서는 현행 붕괴방지성능에서 벗어나 구조물의 손상을 제어할 수 있도록 손상확률에 기반하여 내진성능목표를 설정하는 새로운 내진설계개념이 필요하다. 본 연구에서는 다양한 구조적특성을 지닌 교량을 대상으로 하여 비선형지진해석을 수행하여 지진거동특성을 확인하고, 기준손상도에 대한 취약도곡선을 산정하였다. 이로부터 목표손상확률에 따른 교량구조물의 목표연성도의 특성을 분석하였다.
        4,000원