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        검색결과 523

        121.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multinucleated giant cells appear in a variety forms in different types of oral lesion. However, their nature is still not well understood. Thus, to address this issue, the immunohistochemical characteristics of inflammatory giant cells (Langhans’ giant cells in lesions of tuberculosis and foreign body giant cells in odontogenic keratocysts and squamous cell carcinomas) and tumor giant cells in central giant cell granulomas were compared with those of osteoclasts, the normal giant cell, using a panel of macrophage and osteoclast marker antibodies, such as calcitonin receptor (CT-R), c-Src, Cathepsin K (Cath-K), CD14, RANK, and c-fms. The foreign body giant cells around cholesterol clefts in inflamed odontogenic keratocysts revealed more macrophage-like characteristics than the foreign body giant cells resorbing keratin pearls in squamous cell carcinomas. As such, both cases of foreign body giant cell exhibited immunoreactivity for the macrophage markers, such as CD14, RANK, and c-fms, yet only the latter case exhibited immunoreactivity for the osteoclast markers, such as CT-R and c-Src. Moreover, both cases of foreign body giant cells were positive for TRAP activity, yet negative for Cathepsin K activity. In contrast, the other inflammatory giant cells, Langhans’ giant cells, exhibited immunoreactivity for both the macrophage and osteoclast markers, yet were negative for TRAP activity. Meanwhile, the giant cells in the central giant cell granulomas reacted positively to both the macrophage and osteoclast markers, and were also positive for TRAP activity. Accordingly, these findings suggest that the immunoprofiles of giant cells in oral lesions vary according to the nature of the lesion, despite shared osteoclast and macrophage characteristics. Furthermore, the giant cells in tumorous lesions closely associated with bony destruction revealed more osteoclastic characteristics and their enzyme components were different according to the nature of the lesion
        4,000원
        123.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to optimize the production of immature green cherry tomato pickles and to produce green cherry tomato pickles of good sensory quality. The composition of immature green cherry tomato pickles was optimized using a central composition design with 3 variables and 3 levels. The overall acceptability score, based on sensory evaluation, was best, when the immature green cherry tomato pickles contained 231 g of vinegar, 52.6 g of salt, 168.3 g of sugar, 204 g of tomatoes, and 231 ㎖ of water. The statically predicted optimal formulation of immature green cherry tomato pickles on overall acceptability value was 33.54%(w/w) of vinegar, 7.64%(w/w) of salt, 25.28%(w/w) of sucrose, 33.54%(w/w) of water. The optimal conditions for producing immature green cherry tomato pickles should consider the factors of time and temperature of storage.
        4,000원
        124.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
         ,  , Understanding the ecological complexity and habitat of a species are crucially important to conserve an endangered species. This study evaluated the patch network ecology of the endangered species Parnassius bremeri. The results indicated that 188 individuals were captured and 220 were recaptured, respectively. The sex ratio of female: male was 42:146, males were four times more abundant than females. The average longevity of an adult was 3.93 ± 3.93 days (male, 4.0 ± 3.9, female, 2.5 ± 1.0 days), the maximum longevity was 14 days for males and 13 days for females, respectively. Therefore, the expected longevity of males was longer than that of females. The average emigration distance for the species was 377 m, and the maximum emigration distance was 1550 m. The analysis of patch connectivity and individual colonization revealed that the ideal distance between patches was about 300 m. Moreover, a >, 600 m patch distance decreased the colonization rate severely. We also observed higher immigration and emigration between patches that were clustered in close proximity. This leads us to conclude that a higher number of patches at a close distance is best suited for P.bremeri. We find these results to be crucial to determine a policy to protect and conserve this endangered species.
        4,000원
        125.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 지각 변동을 학습하는 과정에서 나타나는 중학생들의 중간 언어의 유형을 도출하는 것이다. 서울의 한 중학교 2학년 2학급에서 18명의 학생들을 선정하였다. 각 학생들은 총 네 차례에 걸쳐 개별 면담을 실시하였으며, 수집된 자료는 의미 관계와 주제 구조를 중심으로 분석되었다. 연구 결과, 일상 언어를 자원으로 하는 경우, 과학 어휘와 일상 어휘를 병용하는 경우, 그리고 과학 언어를 활용하지만 불충분한 경우와 의미 관계가 부적절한 경우를 합하여 총 8개의 중간 언어 유형이 도출되고 서술되었으며, 이를 바탕으로 조사된 중간언어의 함의를 토의하였다.
        4,600원
        126.
        2012.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, mechanical tests and microstructural analyses including TEM analyses with EDX of precipitates in modified 9Cr-1Mo steel were carried out to determine the cause of embrittlement observed after heat-treatment, which limits the usage of the alloy for power plants. Mod. 9Cr-1Mo steel specimens at austenite temperature were quenched to the molten salt baths at 760˚C and 700˚C, in which the specimens were kept for 10 min ~ 10 hr with subsequent air-cooling. Impact tests showed that the impact value dropped abruptly when the specimens were kept longer than 30 min at ~760˚C reaching to minima in about 1 hr, and then increasing at further retention. The tensile strength of the specimens reached the minimum value without much change afterward, whereas the values of elongation showed the same trend as that of the impact value. The isothermally heat-treated steel at 700˚C also showed a minimum impact value in about 1 hr. These results suggest that the isothermal heattreatment at 760 and 700˚C for about 1 hr induces temporal embrittlement in Mod. 9Cr-1Mo steel. The microstructural examination of all the specimens with extraction replica of the carbides revealed that the specimens with temporal embrittlement had Cr2C, indicating that the cause of the embrittlement was the precipitation of the Cr2C. In addition, TEM/EDX results showed that the Fe/Cr ratio was 0.033 to 0.055 for Cr2C, whereas it was 0.48 to 0.75 for Cr23C6, making the distinction of the Cr2C and Cr23C6 possible even without direct electron diffraction analyses.
        4,000원
        127.
        2011.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        It is well known that modified 9Cr-1Mo steel has a low thermal expansion and high thermal conductivity with excellent high temperature properties compared to austenitic stainless steel. For these advantages, the steel is very popular for the boiler tube of thermal power plants. Normalizing is commonly utilized to obtain martensite in this steel, which shows an unusual toughness for martensite. However, some accidents related to this steel have been reported recently, opening the necessity for further study. As a particular behavior of the steel, an abrupt drop of the impact value has been identified upon tempering at 750˚C for about 1 hour. It is well known that Fe3C forms during autotempering and turns to Cr2C at an early stage and then transforms to Cr23C6. In this study, the cause of the abrupt drop of the impact value was investigated with an impact test, microstructural observation, nanodiffraction and phase analyses using instruments such as optical and transmission electron microscopes (TEM) with an extraction carbon replica of the carbides. The analyses revealed that the M2C that formed when retained for about 1 hour at 750˚C causes a drastic decrease in the mechanical properties. The sharp drop in mechanical properties, however, disappeared as the M2C transformed into M23C6 with longer retention.
        3,000원
        128.
        2011.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to identify the flow resistance of the bottom trawl net. The bottom trawl net being used in the training ship of Chonnam National University was selected as a full-scale net, and model nets such as 1/10, 1/25 and 1/50 of the actual net were made. Total resistance of the net part, the height of the net mouth and the flow resistance of components of the net such as wing, bag and cod-end part was measured, converted into full-scale and compared. Additionally, the model rule of Tauti (1934), which has been most frequently used in fishing net modeling experiments, was applied to interpret flow resistance and scale effect of model experiment was investigated. Presumed that the flow resistance R is R=kSr2 against the flow velocity of each net r, resistance coefficient k was calculated by substituting R, r and S of the net. From the result, it was found that k decreases exponentially when u increases which makes k=cr-m. Whereas m of each net is ranged between 0.13-0.16 and there was not significant difference between nets. c does not show big difference in 1/10 and 1/25 model and the value itself was relatively bigger than in 1/50 model. The height of the net mouth of 1/25 and 1/50 model net h decreases exponentially according as r increases to make h=dr-n. Whereas d and n values were almost same in two nets. Additionally, when resistance of cod-end, wing and bag part in 1/25 and 1/50 model nets, both nets showed big resistance in bag part when flow is 1m/s as more than 60%. Wing and cod-end part showed almost same value or wing part had little bit larger value. On the other hand, when reviewing the reasons why both models showed difference in 1/50 model while c value against the resistance coefficient k did not show big difference in 1/10 and 1/25 model, it is inferred that the difference occurred not from material difference but from the difference in net size according to scale. It was judged that they are the scale effects concomitant to the model experiments.
        4,000원
        129.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한려해상국립공원 특별보호구로 지정된 히어리군락의 생육상태와 향후 자생지의 지속적인 보전 및 관리를 위한 기초자료로 활용하고자 분석하였다. 히어리군락은 계곡부에 위치하고 있었으며, 암 및 자갈 노출도가 60%이상으로 식피율이 낮게 나타났고 계곡범람으로 조사구의 훼손과 교란현상이 나타나고 있었다. 히어리군락의 교목층은 졸참나무와 소나무가 우점하였으며, 아교목층은 히어리, 당단풍, 사람주나무, 편백, 산딸나무가 우점하였다. 관목층은 작살나무, 청미래덩굴 등이 우점하였으며, 초본층은 애기나리 등이 우점하였다. 계곡부에 위치한 히어리군락의 3년동안(2008∼2010년) 생육기인 5∼9월의 강수량 및 강우일수는 점차 증가하여 침식 및 훼손 등의 교란가능성이 높았으며 히어리가 주로 수광량이 높은 계곡부에 분포함으로서 성숙된 종자의 산포가 토양층이 얕은 계곡으로 분산되어 유묘 발생에 의한 개체군 증가가 빈약하였다.
        4,000원
        133.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The autothermal reforming reaction of methane was investigated to produce hyd rogen with Ni/CeO2-ZrO2, Ni/Al2O3-MgO and Ni-Ru/Al2O3-MgO catalysts. Honeycomb metalli c monolith was applied in order to obtain high catalytic activity and stability in autothermal r eforming. The catalysts were characterized by XRD, BET and SEM. The influence of various catalysts on hydrogen production was studied for the feed ratio(O2/CH4, H2O/CH4). The O2/CH4 and H2O/CH4 ratio governed the methane conversion and temperature profile of reactor. Th e reactor temperature increased as the reaction shifted from endothermic to exothermic reactio n with increasing O2/CH4 ratio. Among the catalysts used in the experiment, the Ni-Ru/Al2O3-MgO catalyst showed the highest activity. The 60% of CH4 conversion was obtained, and th e reactor temperature was maintained 600℃ at the condition of GHSV=10000h-1 and feed ratio S/C/O=0.5/1/0.5.
        4,000원
        134.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The safety of liquid-type herbal preparations (47 samples) and beverages containing herbal medicines (18 samples), which are distributed in Gyeonggi province was studied by analyzing heavy metals,benzo(a)pyrene, preservatives and sugar content and to explain the differences between medicine and food based on the labeling standards. The herbal preparation is regarded as medicine and can be differentiated from the beverages containing herbal medicine, which is food, based on the fact that the herbal preparation should be labeled with usage,dosage, efficiency and effect. The mean concentrations of Pb, As, Cd, Hg were found to be 0.014 mg/kg, 0.113 mg/kg, 0.004 mg/kg and 0.003 mg/kg in herbal preparation and 0.009 mg/kg, 0.122 mg/kg, 0.003 mg/kg and 0.002 mg/kg in beverages containing herbal medicines, respectively. In 10 cases of herbal preparations and 6 cases of beverages containing Rehmanniae Radix Preparata (Sukjihwang), benzo(a)pyrene was not found. According to preservative test on herbal medicine, dehydroacetic acid was found less than the indicated content in 6 cases out of 37 cases, which labeled with preservatives, and benzoic acid, dehydroacetic acid and methylparaben were contained with 164.0~198.0 mg/kg, 149.8~272.5 mg/kg and 88.4 mg/kg, respectively, in 3 cases out of 10 cases, which was not labeled with preservatives. Among 16 cases of beverages containing herbal medicines, 3 cases of preservative-labeled beverages had the preservatives, and the rest of all, which was not labeled with preservatives, did not show that they contain any preservative, therefore, it was suitable for the labeling standards. As a result of sugar content test, preservative-labeled products were not appreciably different from the others.
        4,000원
        135.
        2011.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was to assess the lifetime cancer and non-cancer risk on exposure to volatile organic compounds (VOCs) and formaldehyde of worker and user at public facilities in Korea. We measured the concentrations of formaldehyde and VOCs in indoor air at 160 public buildings that 5 kinds of public facilities (30 hotel, 30 fitness center, 25 gosiwon, 30 reading-room and 45 video-room) all over the country. There were estimated the human exposure dose and risks with averages of the using-time and frequency for facility users and office workers, respectively. Carcinogens (benzene and formaldehyde) were estimated the lifetime excess cancer risks (ECRs). Non-carcinogens (toluene, ethylbenzene, xylene, and styrene) were estimated the hazard quotients (HQs). HQs of four non-carcinogens did not exceed 1.0 for all subjects in all facilities. Higher HQs of toluene were observed at the reading-room. The average ECRs of formaldehyde and benzene for facility worker and user were 1×10-4~1×10-6 level in all facilities. The estimated ECRs for reading-room were the highest and the fitness center and gosiwon were the next higher facilities. Because lifetime ECRs of carcinogens exceeded 1×10-4 for facility worker in the most facilities, risk management of formaldehyde and benzene in the facilities was necessary. IAQ guidelines should be determined strictly to prevent occurrence of disease caused by poor IAQ beforehand.
        4,500원
        136.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, we developed optimal heat supply algorithm which minimizes the heat loss through the distribution pipe line in group energy apartment. Heating load variation of group energy apartment building in accordance with outdoor air temperature was predicted by the correlation obtained from calorimeter measurements of whole households of apartment building. Supply water temperature and mass flow rate were conjugately controlled to minimize the heat loss rate through distribution pipe line. Group heating apartment located in Hwaseong city, Korea, which has 1,473 households divided in 4 regions, was selected as the object apartment for verifying the present heat supply control algorithm. Compared to the original heat supply system, 10.4% heat loss rate reduction can be accomplished by employing the present control algorithm.
        4,000원
        140.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 수확시기가 옥수수 사각 압축곤포사일리지의 품질에 미치는 영향을 구명하기 위하여 2009년부터 2010년까지 국립축산과학원에서 수행되었다. 옥수수 사일리지 전용 품종인 광평옥을 이용하여 숙기별 3회(유숙기, 황숙기 및 완숙기)에 걸쳐 수확을 하여 사일리지로 조제하였다. 숙기가 진행됨에 따라 옥수수 원형곤포 사일리지의 조단백질 함량은 감소하는 경향을 보였으나(P<0.05) ADF 및 NDF 함량은 차이가 나타나지 않았다. 그리고 TDN 및 in
        4,000원