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        검색결과 82

        69.
        1994.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        비정질 Si1-xGex(X=0, 0.14, 0.34, 0.53)합금박막의 결정화거동을 X-ray diffractometry(XRD)와 투과전자현미경(transmission electron microscopy, TEM)을 이용하여 조사하였다. 비정질 박막은 열산화막(thermal oxide, SiO2)이 입혀진 Si기판위에 MBE(Molecular Beam Epitaxy)를 이용하여 300˚C에서 증착하였으며 각 Ge조성에 해당하는 기편들을 500˚C ~ 625˚C에서 열처리한 다음 XRD를 이용하여 결정화분율과 결정화후 박막의 우선순방위(texture)경향ㅇ르 조사하였다. 또한 TEM을 사용하여 열처리한 박막의 미세구조를 분석하였다. XRD분석결과 박막내의 Ge함량의 증가는 결정화에 대한 열처리시간을 크게 감소시키는 것으로 밝혀졌다. 또한 결정화후 강한(111) 우선방위를 나타내는 Si박막과는 달리 Si1-xGex합금은 (311)우선방위를 가지는 것을 알았으며 이는 비정질 Si박막과 Si1-xGex박막의 결정화기구에 현저한 차이가 있음을 암시한다. TEM관찰에서, 순수한 Si박막은 결정화후 결정립이 타원형이나 수지상(dendrite)형태를 취하고 있었으며 결정립내부에 미페쌍정이나 적층결함들의 많은 결정결함들이 존재하고, 결정립의 성장이 이들 결함을 따라 우선적으로 성장함을 알 수 있었다. 반면에 Si0.47Ge0.53의 경우에서는 결정립모양이 원형에 가까운 동축정(dquiaxed)형상을 하며 결정립내부의 결함밀도도 매우 낮았다. 특히 Si에서 보았던 결정립성장의 방향성은 관찰되지 않았다. 이상의 결과에서 비정질 Si1-xGex(합금박막의 결정화는 Ge이 포함되지 않은 순수한 Si의 twin assisted growth mode에서 Ge 함량의 증가에 따라 ?향성이 없는 random growth mode로 전개되어간다고 결론지을수 있다.
        4,200원
        71.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구에서는 다양한 식품유해미생물에 대한 길항작용 및 항산화활성이 우수한 B. subtilis SRCM102046 균주를 식품보존 소재로서 이용하기 위해 반응표면분석법을 이용하여 균체 증량을 통한 항균활성 및 항산화활성 증대를 도모하고자 하였다. SRCM102046의 산업적 활용을 위한 성장조건을 최적화하기 위해 배양시간에 따른 균체 성장을 조사하였으며, 통계학적 기법인 반응표면분석법을 사용하였다. SRCM102046의 최적 성장을 위한 배지 성분을 선별하기 위해 Plackett-Burman design을 이용하였으며, PBD 결과 선별된 배지 성분으로 molasses, sucrose, peptone으로 예측되었다. 각 배지 성분의 최적농도를 결정하기 위한 방법으로 central composite design을 이용하였으며, 최종적으로 예측된 각 배지 성분의 농도는 molasses 7 g/L, sucrose 7 g/L, peptone 2 g/L로 예측되었다. 이때의 균체량은 22.03±1.30 g/L로 예측되었으며, 통계분석을 통해 실험모델의 적합성을 확인하였다. 또한, 실험 모델을 수행하여 건조균체량을 측정한 결과 22.02±0.35 g/L로 측정되어 실험모델에 의해 예측된 값이 오차범위 내에 존재하여 모델의 신뢰성이 매우 높음을 확인하였으며, 이는 실험모델에 의해 예측된 최적배지 사용시 최적화 이전의 LB 배지에서의 균체량(2.47±0.03 g/L)대비 약 9배의 균체량이 증가함을 확인하였다. 또한 최적배지에서 B. subtilis SRCM102046 배양 시 항균활성은 대조구로 사용된 LB 배지에서의 항균활성 대비 최대 140% 향상되었으며, 항산화활성은 약 100.41% 증가함을 확인하였다. 본 연구를 통하여 식품보존제로서B. subtilis SRCM102046의 산업화를 위한 배지최적화를 수행하였으며, 추후 박테리오신의 정제 및 특성 등에 대한 세부적인 연구가 필요하지만 본 연구를 통해 확립된 배양조건을 기반으로 식품보존 소재의 측면에서 매우 유용한 자료로 활용될 수 있을 것으로 기대된다.
        72.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        This study has been conducted to understand the relationships such as interspecific interactions between species and landscapes within and outside of agricultural land by identifying the flora features of Cornus officinalis farmlands in Gurye which designated as Korea's Important Agricultural Heritage System. For this, the flora of vascular plants was surveyed in every land uses of two representative districts. These two districts represent the own features of Cornus officinalis farming area which including land uses like forests(especially pine tree), valley, farmland(rice paddy, farms, Cornus officinalis farmland), and residence. Also differences in flora by stone wall’s existence and Cornus officinalis’s DBH were surveyed. As a result, Cornus officinalis farmlands showed the various vascular plants than the other land uses. According to the existence of stone wall in Cornus officinalis farmlands, there were no differences in appearance flora. But the flora in Cornus officinalis farmlands which have different Cornus officinalis’ DBH(Divided into average over 15cm and under 8cm), various plants were showed in average over 15cm than average under 8cm. In conclusion, Cornus officinalis farmlands have been actively engaged in various types of land use and species exchanges, including forests, valleys, villages, and fields, and it has been confirmed that it acts as an ecological axis connecting forests to villages.
        73.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study, we tried to screen the Bacillus strain having safety probability by isolation of strains from traditional fermented food, measurement of probiotic properties, and the fermentative characteristics of Cheonggukjang. We isolated 400 Bacillus-like isolates from traditional fermented foods. Selected strains examined on the prevalent characteristic such as extracellular enzyme and antibacterial activities, and their safety probability was confirmed by biogenic amine productivity, hemolytic, and harmful substances and enzyme productivity. We selected the 5 strains by analysis of biogenic amine, antibacterial and B. cereus toxic associated gene. Five selected strains were examined on cell surface hydrophobicity, and bile and acid tolerance, and we selected the SRCM100730 as the final strain. SRCM100730 was confirmed B. amyloliquefaciens by 16S rRNA sequencing, and named the B. amyloloquefaciens SRCM100730 (KCCM11966P). Finally, we manufactured Cheonggukjang using SRCM100730 for confirmation of fermentation properties. Manufactured Cheonggukjang did not contain B. cereus, and showed that γ-PGA and extracellular enzyme activities were superior to commercial Chunggukjang. Amino nitrogen content was 544.02 mg% and 26 free amino acid were detected, and the bitterness-related amino acid content was lower than commercial Cheonggukjang. Especially, the amount of GABA was 3 fold higher than commercial Cheonggukjang. These results suggest that SRCM100730 have high availability in commercial probiotics market and fermented food industry.
        74.
        2017.09 서비스 종료(열람 제한)
        Recently, the use of duplex stainless steel which has a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel has been increased in a variety of industrial fields. Especially, STS329FLD with lower nickel content and higher yield strength compared with austenitic stainless steel has been developed. In this paper, experiments have been conducted to investigate the structural behaviors of single shear duplex stainless steel(STS329FLD) bolted connection with four bolts. Specimens with relatively long end distance failed by block shear fracture accompanied with curling (out-of-plane deformation) and the curling reduced the ultimate strength.
        75.
        2017.08 KCI 등재 서비스 종료(열람 제한)
        Background: The current regulations regarding the storage of medicinal herbs do not define the storage temperature; instead, but the only requirement is that the plastic bags used for storing the medicinal herbs should be tightly sealed during storage. The practice of storing medicinal herbs at room temperature (28℃), causes many problems, including growth of insect pests on the stored medicinal herbs. Thus, it is necessary to understand the effect of insect pests on the quality of medicinal herbs stored at room temperature (28℃) for the improving the relevant regulations. Methods and Results: Cnidium rhizome and Angelica radix were infested with Lasioderma serricorne F. adults and incubated at 28℃ for 2.5 and 5 months. The population of L. serricorne was established rapidly, and left many holes, cadavers, and feces on the stored medicinal herbs, thereby greatly damaging the product appearance and hygiene. In addition, active ingredients of the medicinal herbs were significantly decreased, probably reducing their medicinal quality as well. Conclusions: These results indicate that the current regulations are not sufficient to prevent the establishment of storage insect pests and guarantee the quality and hygiene of stored medicinal herbs. Therefore, it is necessary to devise proper storage protocols and upgrade the current relevant regulations to maintain the quality of medicinal herbs during storage.
        76.
        2017.05 서비스 종료(열람 제한)
        Background : The practice of keeping the medicinal herbs at room temperature causes many problems, but due to lack of sufficient field research and study, it is difficult to improve related regulations and safety management. Methods and Results : The Cnidium Rhizome and Angelica gigas Root were inoculated with Lasioderma serricorne F. and incubated at 28℃ for 2.5 months and 5 months. After five months, the number of Lasioderma serricorne F. in Cnidium Rhizome increased from 30 to 1,429 (about 47 times). In the same period, the number of insects in Angelica gigas Root increased from 30 to 663 (about 22 times). Due to the rapid increase in pest population, hygiene deteriorated, changes in the active ingredient and appearance quality of the herbal medicines, which greatly damaged the value of the herbal medicine. Conclusions : These results show that current regulation requiring only sealing and not specifying the storage temperature do not guarantee quality safety. Therefore, it is necessary to establish appropriate preservation standards and improve management regulations in order to preserve safety.
        77.
        2015.07 서비스 종료(열람 제한)
        최근 작물유전체 기술이 비약적으로 발전하고 있어서 이러한 기술과 얻어진 유전체정보를 활용할 경우 작물육종이 새롭게 도약하는 계기가 될 것이라 기대하고 있다. 그러나 실상 작물유전체 정보가 작물분자육종에 효과적으로 활용되고 있지 못하고 있다. 작물육종의 궁극적인 목표는 원하는 표현형질을 갖는 품종을 개발하는 것이나 작물유전체정보나 개별 오믹스 정보만으로는 전통적인 표현형지표와 연결시켜 작물육종에 활용하기 어렵다. 다양한 생명공학적, 분자육종적 기술을 활용해 보다 다양한 계통창출이 가능해 졌으나 전통적인 표현형평가방식으로는 효과적으로 우량계통을 선발하기 어렵고, 비용도 많이 소요된다. 따라서 새로운 개념의 식물표현체 정보(열영상, 형광영상, RGB영상 등)를 작물유전체 정보와 연계시키고, 작물의 주요형질에 식물표현체정보를 연계시킨다면 작물육종의 효율성제고에 활용 가능할 것으로 기대하고 있다. 따라서 이번 발표에서는 식물표현체 기술을 활용하여 주요 환경스트레스에 대한 벼와 콩의 생리적 반응을 대용량으로 조기진단하고 이러한 진단방법과 결과를 환경스트레스 내성 계통이나 품종선발에 얼마나 효율적으로 활용할 수 있는지 평가한 결과를 보고하고자 한다. 아울러 그동안의 연구결과와 경험을 바탕으로 식물표현체 기술을 활용한 작물분자육종 효율증진 방안과 작물유전체 연구에의 활용가능성 등을 제시하고자 한다.
        78.
        2013.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Strawberries are among the leading ready-to-eat agricultural products that have superior taste and nutrition. Thus, consumer concerns about the safety of eating strawberries are growing. To evaluate the contamination levels of strawberries according to their cultivation methods (nutriculture, pesticide-free culture and organic farming) and parts [fruit (flesh), stalk (pedunle) and leaf (calyx)], 1,020 parts of strawberry samples were collected at 12 farms in Nonsan-si and quantitatively or qualitatively examined for the indicators of food safety and food poisoning bacteria. The total aerobic bacteria count in the whole samples was 2.3~6.8 log10 CFU/g, and coliform bacteria were detected in 14.2% of the whole samples with a contamination level range of 2.1~4.5 log CFU/g. E. coli were detected in 0.9% of the whole samples with a contamination level range of 2.1~2.8 log CFU/g. The analysis of the bacterial levels according to the cultivation methods showed that the total aerobic bacteria and coliform counts were higher in the strawberries that were grown via organic farming than in those that were grown via nutriculture and pesticide-free culture. However, the E. coli counts of the strawberries that were grown via organic farming and via pesticide-free culture were similar and differed from that of the strawberries that were grown via nutriculture. The analysis of the contamination levels according to the parts of the strawberries showed that the total aerobic bacteria, coliform and E. coli counts of the fruits, stalks and leaves of the strawberries did not significantly differ. Staphylococcus aureus was detected in two organically grown strawberries, but Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected in the whole samples. These results show that the bacterial contamination levels of the strawberries differed based on their cultivation methods. Thus, a suitable method of reducing the bacterial contamination levels of strawberries according to their farming methods is needed
        79.
        2013.04 서비스 종료(열람 제한)
        In order to reduce the carbon dioxide exhaust quantity and the energy amount and the waste which becomes the global warming primary reason recently, the most efficient method was focused on the long-life building in Structural field. So in order to improve seismic capacity, new shape steel damper may be used in bolted connection, which made reuse of member impossible owing to serious brittle fracture of main member such as beam and column. To solve above problem, new type connection was developed and tested. As result of test, new type connection was shown good seismic capacity and main member such as beam and column were stable behavior.
        80.
        2013.04 서비스 종료(열람 제한)
        This paper presents test results of bending and weld joint of the HSA800. HSA800 for the high performance steel has a minimum 800MPa tensile strength. HSA800 can effectively reduce the size and thickness of structural member for high-rise building. Bending test and weld joint test of HSA800 are conducted to verify fabrication and performance of steel pile. Test results show that HSA800 is appropriate to make a heavy wall steel pipe. The fracture is occurred at the base metal of weld joint which can exhibit strength higher than its base metal.
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