• 한국식품과학회지
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• 제22권4호
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• pp.386-392
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• 1990

장려품종 콩 19종의 단백질 특성 비교로 추출용매에 따른 단백질 획분의 분포, 전기영동 특성 및 아미노산 조성을 조사하였다. 이들 콩에 함유된 글리시닌은 콩단백질의 $48.19{\sim}58.86%$를 차지하였으며 다른 획분에 비해 프롤라민의 비율은 콩의 품종간에 큰 차이를 보였다. 콩 단백질의 전기영동 양상은 팔달, 장백, 장엽, 단엽, 남천 및 S-138이 $21.5{\sim}31.0kd$ 범위에서 보인 단백질 분리대의 차이를 제외하고서는 품종간의 차이가 없었다. 콩에 소량 함유된 아미노산류는 시스테인 메티오닌 티로신 및 트레오닌이었으며 티로신의 비율이 다른 아미노산에 비해 품종에 따른 차이가 가장 큰 것으로 나타났다.

• 한국과학교육학회지
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• 제42권5호
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• pp.557-566
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• 2022

이 연구는 중학생의 증강현실을 활용한 2인 1조의 소집단 학습에서 나타나는 언어적·물리적 상호작용을 분석하였다. 서울 시내 중학교 2학년 학생 12명이 용해도, 녹는점과 끓는점 개념에 대해 증강현실을 활용한 2인 1조의 소집단 학습에 참여하였다. 이 수업은 녹음 및 녹화되었으며, 수업이 종료된 후 학생들을 대상으로 반구조화된 면담을 시행하였다. 연구 결과는 개별 진술 단위, 상호작용 단위 그리고 물리적 상호작용으로 각각 분석하였다. 개별 진술 단위에서는 정보 설명과 정보 질문의 비율이 높게 나타났다. 상호작용 단위는 단순 상호작용, 정교화 상호작용의 비율이 높았다. 정교화 상호작용을 하위 영역별로 보면, 누적형 상호작용의 비율이 높았으며 뒤를 이어 교정형 상호작용이 나타났다. 물리적 상호작용은 활동지를 쓰는 행동과 가상 객체를 관찰하는 행동의 비율이 높았다. 이상의 연구 결과를 바탕으로 중학생 2인의 증강현실을 활용한 소집단 학습을 효과적으로 구성할 수 있는 적절한 방안을 제시하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.19-19
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• 2003

The injection of spins into nonmagnetic semiconductors has recently attracted great interest due to the potential to create new classes of spin-dependent electronic devices. A recent strategy to achieve control over the spin degree of freedom is based on dilute ferromagnetic semiconductors. Ferromagnetism has been reported in various semiconductor groups including II-Ⅵ, III-V, IV and II-IV,-V$_2$, which will be reviewed. On the other hand, to date the low solubility of magnetic ions in non-magnetic semiconductor hosts and/or low Curie temperature have limited the opportunities. Therefore the search for other promising ferromagnetic semiconducting materials, with high magnetic moments and high Curie temperatures (Tc), is of the utmost importance. In this talk, we also introduce new pure ferromagnetic semiconductors, MnGeP$_2$ and MnGeAs$_2$, exhibiting ferromagnetism and a magnetic moment per Mn at 5K larger than 2.40 ${\mu}$B. The calculated electronic structures using the FLAPW method show an indirect energy gap of 0.24 and 0.06 eV, respectively. We have observed spin injection in MnGeP$_2$ and MnGeAs$_2$ magnetic tunnel junctions through semiconducting barriers.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.39-45
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• 1997

Introduction : Polyimides are one of the most important classes of the high performance polymers due to their excellent electrical, thermal, and high-temperature mechanical properties. But their uses are limited because of their poor solubility. Most polyimide derivatives are processed in the form of polyamic acids, which are subsequently converted into the imide structures.Recently, it has been found that the soluble polyimides with large molecular weight sufficient to application. For enhancing processability, the majority of approaches have involved the following factors. As much as, the separation of the imide ring along the back-bone, that is to say, reducing the density of imide ring in the repeat structure. The introduction of bulky substituents along the back-bone, in order to enhance the free volume of main-chain. The incorporation of flexible or thermally stable linkages in the main-chain, reducing the packing force. The disruption of symmetry or recurrence regularity through copolymerization in order to reduce crystallnity.The objectives of this investigation are the synthesis and characterization of soluble polyimides as membrane materials by the single-step polymerization and the preparation of the asymmetric polyimide membrane by using phase inversion technique. In the present study, three series of polyimide derivatives are synthesized; H series is homopolyimides, A series is prepared from single dianhydride and two diamines, B series is yielded from two dianhydrides and a diamine. The dope solution was directly prepared from the PI solution via one step polymerization from monomers.

• Molecules and Cells
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• 제28권4호
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• pp.397-401
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• 2009

Flavonoids are a group of polyphenolic compounds that have been recognized as important due to their physiological and pharmacological roles and their health benefits. Glycosylation of flavonoids has a wide range of effects on flavonoid solubility, stability, and bioavailability. We previously generated the E. coli BL21 (DE3) ${\Delta}pgi$ host by deleting the glucose-phosphate isomerase (Pgi) gene in E. coli BL21 (DE3). This host was further engineered for whole-cell biotransformation by integration of galU from E. coli K12, and expression of calS8 (UDP-glucose dehydrogenase) and calS9 (UDP-glucuronic acid decarboxylase) from Micromonospora echinospora spp. calichensis and arGt-4 (7-O-glycosyltransferase) from Arabidopsis thaliana to form E. coli (US89Gt-4), which is expected to produce glycosylated flavonoids. To test the designed system, the engineered host was fed with naringenin as a substrate, and naringenin 7-O-xyloside, a glycosylated naringenin product, was detected. Product was verified by HPLC-LC/MS and ESI-MS/MS analyses. The reconstructed host can be applied for the production of various classes of glycosylated flavonoids.

• 한국과학교육학회지
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• 제43권2호
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• pp.125-137
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• 2023

이 연구에서는 증강현실을 활용한 소집단 학습에서 나타나는 중학생의 지식 형성 담화의 유형과 지식 형성 과정을 탐색하였다. 서울시 소재의 남녀공학 중학교 2학년 학생 8명이 증강현실을 활용하여 용해도 개념, 끓는점과 녹는점 개념에 대한 소집단 학습에 참여하였다. 수업은 2차시에 걸쳐 이루어졌으며 모두 녹음 및 녹화하였다. 이후, 연구에 참여한 학생들은 반구조화된 면담에 참여하였다. 지식 형성 담화의 유형에서 지식 공유와 지식 구성의 비율은 비슷하게 나타났다. 지식 공유에서는 기초 수준의 토의, 증강현실의 핵심 요소 확인의 순으로 나타났고, 사전 지식의 회상은 거의 나타나지 않았다. 지식 구성에서는 심화 수준의 토의가 가장 높았고, 그다음으로 다른 수준에서의 공유 및 비판과 현재의 설명 수준을 넘어서려는 노력이 나타났으며, 두 요소의 비율은 유사하였다. 지식 공유의 하위 요소인 기초 수준의 토의와 증강현실의 핵심 요소 확인은 지식 구성의 하위 요소인 현재의 설명 수준을 넘어서려는 노력과 다른 수준에서의 공유 및 비판으로 발전되어 나타났다. 지식 형성 과정을 시각화했을 때, 모든 학생의 누적 영향 값 그래프는 우상향하는 형태로 나타났지만, 소집단별로 두 학생의 누적 영향 값은 차이가 나타나는 경우가 있었다. 이상의 연구 결과를 통해 증강현실을 활용한 중학생의 소집단 학습 촉진 방안을 제시하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제11권5호
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• pp.530-537
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• 1998

The proportion of dry matter (DM) and mineral elements (Ca, Mg, P, Na, K, Zn) released from eight feeds (2 rice straws, RSI and RS2; 2 grasses, NB21 and guinea; 2 leguminous fodders, glyricidia and erythrina; jak leaves and rice bran) were studied using the nylon bag procedure. Bag incubations up to 10 days were performed in the rumen of cows fed on a ration consisting of 50% wheat straw and 50% hay. Both the type of feed and the incubation time in the rumen significantly influenced (p < 0.01) the proportion of minerals released. In legumes, jak leaves and rice bran about 80% of the potentially degradable DM fraction was solubilized within 24 h in the rumen, and with the grasses, rice straws and jak leaves a considerable proportion of DM was released between 48 and 240 h in the rumen. During the early hours of incubation (up to 24 h) there were distinct differences between and within the feed classes in their ability to release all mineral elements studied. In all test feeds, high proportions of Mg and K were released within 24 h. Some feeds showed a tendency to ad/absorb Ca (grasses, rice straws and rice bran), P (jak leaves, rice straws), Na (glyricidia and rice bran) and Zn (jak leaves) from water and rumen fluid, and this was partly related to the low initial concentration. In terms of absolute quantity of mineral released, legumes (erythrina is superior to glyricidia) are a good source of Ca, Mg, P and Zn, and jak leaves a good source of Ca and Na. Within grasses, guinea contains appreciable quantity of available Mg and P. Rice bran is rich in available Mg, P and Zn.

• 한국과학교육학회지
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• 제25권5호
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• pp.555-562
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• 2005

이 연구에서는 개념 변화 수업에서 협동적 학습 환경의 효과를 개념 이해도, 성취도, 과학 학습 동기, 과학 수업에 대한 태도 및 수업 참여도에 대한 인식 측면에서 조사하였다. 1개 남녀 공학 중학교의 2학년 2개 학급을 비교 집단과 처치 집단으로 각각 배치하고, '물질의 특성' 단원의 밀도, 끓는점, 어는점, 용해도에 대하여 11차시 동안 수업을 실시하였다. 처치집단에서는 협동적 개념 변화 수업을 실시하였고, 비교 집단에서는 개별적 개념 변화 수업을 실시하였다. Mann-Whitney Test 결과, 처치 집단의 개념 검사 점수와 성취도 검사 점수가 비교 집단에 비해 유의미하게 높았으며, 처치 집단의 수업 참여도에 대한 인식이 비교 집단에 비해 더 긍정적인 것으로 나타났다. 이원 공변량 분석 결과, 처치 집단의 학습 동기 검사 점수가 비교 집단에 비해 유의미하게 높았으나, 과학 수업에 대한 태도에서는 두 집단 간에 유의미한 차이가 나타나지 않았다.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.322-328
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• 2013

In this study, we show the expression and purification of the human recombinant farnesoid X receptor (FXR)- ligand binding domain (LBD) protein in E. coli using a double cistronic vector, pACYCDuet-1, as a soluble form. We describe here the expression and characterization of a biologically active $FXR-LBD_{(248-476)}$. When expressed in the influence of bacterial promoters ($P_{T7}$ and $P_{Tac}$) of the single cistronic expression vectors, the human recombinant $FXR-LBD_{(248-476)}$ was found to be totally insoluble. However, by using a double cistronic expression vector, we were able to obtain the human recombinant $FXR-LBD_{(248-476)}$ in a soluble form. To allow for biological activities, we have subcloned into the pACYCDuet-1 vector, expressed in E. coli cells at some optimized conditions, and purified and characterized the human recombinant active $FXR-LBD_{(248-476)}$ proteins using the fluorescence polarization assay. This suggests that the expression of FXR-LBD in a double cistronic vector improves its solubility and probably assists its correct folding for the biologically active form of the proteins. We suggest that this may represent a new approach to high expression of other nuclear receptors and may be useful as well for other classes of heterodimeric protein partners.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.