• 한국초등과학교육학회지:초등과학교육
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• 제30권3호
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• pp.330-339
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• 2011

This study was to investigate effects of instruction using the history of science on elementary school students' science learning motivation. Subjects were 48 students of two groups in the 5th Grade in Bucheon City. A Experimental group of 24 was instructed 20 lessons in Unit 1~7 using the history of science for a 11-week period. In this study, the instructional contents were selected by stories about scientists, discoveries or anecdotes about natural phenomena and related learning topics in national science curriculum. And they are presented by writings with pictures, cartoons, PPT materials and a script. Students play various learning activities such as exchanging opinions after reading instructional content, making a book or a newspaper, playing in a drama and representing by picture. A control group of 24 was instructed by traditional teaching methods in same period. To compare difference of instruction effects of the two groups, the score of pre-test and post-test were both estimated by t-test. The results of the study were as follows. Students of experimental group showed statistically a more significant increase in the science learning motivation than control group students (p<.05). Each of attention (A), relevance (R), satisfaction (S) sub-elements of learning motivation were higher in the experimental group and it was showed the instruction using the history of science was effective in improving of science learning motivation.

• Journal of Microbiology and Biotechnology
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• 제13권2호
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• pp.217-224
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• 2003

Previously, we developed a CHO cell line (CHO-OTC1-Al9) that expresses the first two enzymes in the urea cycle and exhibits a higher ammonia-removing ability and faster growth rate than a vector-controlled CHO cell line (CHO-neo-5). The current study was undertaken to develop a cell line with an ammonia-removing ability higher than the cell line developed previously. To accomplish this, CHO cell lines expressing the first three, first four, or all five enzymes of the urea cycle were constructed using a stable transfection method. Finally, the CHO-AS-16, CHO-AL-19, and CHO-Arg-11 cell lines expressing the first three, first four, and all five enzymes of the urea cycle, respectively, were selected and found to exhibit higher ammonia-removing ability than the CHO-OTC1-Al9 cell line. Among the three selected cell lines, CHO-AL-19 showed the highest ammonia-removing ability and highest cell viability at a higher cell density, with 40% and 15% lower ammonia concentration in the, culture media than that of CHO-neo-5 and CHO-OTC1-A19 cell lines, respectively. CHO-AL-19 also showed 44% and 10% higher cell viability than the CHO-neo-5 and CHO-OTC-Al9 cell lines, at a higher cell density, respectively. The ammonia concentrations in the culture media were expressed as the ammonia concentration/cell, and the CHO-AL-19 cells revealed 45-60% and 20% lower ammonia concentration/cell than the CHO-neo-5 and CHO-OTC1-Al9 cells, respectively.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.828-834
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• 2010

An ethanol-producing yeast strain, CHFY0201, was isolated from soil in South Korea using an enrichment technique in a yeast peptone dextrose medium supplemented with 5% (w/v) ethanol at $30^{\circ}C$. The phenotypic and physiological characteristics, as well as molecular phylogenetic analysis based on the D1/D2 domains of the large subunit (26S) rDNA gene and the internally transcribed spacer (ITS) 1+2 regions, suggested that the CHFY0201 was a novel strain of Schizosaccharomyces pombe. During shaking flask cultivation, the highest ethanol productivity and theoretical yield of S. pombe CHFY0201 in YPD media containing 9.5% total sugars were $0.59{\pm}0.01$ g/l/h and $88.4{\pm}0.91%$, respectively. Simultaneous saccharification and fermentation for ethanol production was carried out using liquefied cassava (Manihot esculenta) powder in a 5-l lab-scale jar fermenter at $32^{\circ}C$ for 66 h with an agitation speed of 120 rpm. Under these conditions, S. pombe CHFY0201 yielded a final ethanol concentration of $72.1{\pm}0.27$ g/l and a theoretical yield of $82.7{\pm}1.52%$ at a maximum ethanol productivity of $1.16{\pm}0.07$ g/l/h. These results suggest that S. pombe CHFY0201 is a potential producer for industrial bioethanol production.

• 한국작물학회지
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• 제53권1호
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• pp.85-92
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• 2008

신팔달콩2호와 GC83006를 교잡하여 총 118개의 $F_7$ 계통을 육성하였다. 127개의 분자마커를 사용하여 유전자지도를 이용하여 종실 및 생육특성에 대한 QTLs분석을 실시하였으며 그 결과를 요약하면 다음과 같다. 1. 100립중, 경장, 엽면적 그리고 개화까지 일수는 정규분포를 보였다. 100립중을 제외한 3개의 형질에서 양친의 값을 벗어나는 초월변이 계통이 관찰되었는데, 특히 개화까지의 일수는 개화기가 지연되는 쪽으로 초월변이 계통이 다수 관찰되었다. 2. 100립중, 경장, 엽면적 그리고 개차까지 일수에 대한 QTL분석 결과, 전체 7개의 QTL이 탐지되었다. 100립중에 관여하는 3개의 QTL은 전체변이의 $10.1%\;{\sim}\;12.5%$를 설명하였고, 경장은 전체변이의 22%를 설명하는 1개의 QTL이 탐지되었다. 엽면적은 전체 변이의 10% 및 8.6%를 설명하는 2개의 QTL이 탐지되었으며 개화기 일수는 전체 변이의 41.0%를 설명하는 1개의 QTL이 탐지되었다. 3. 신팔달콩2호와 GC83006의 모용은 각각 회색과 갈색이었으며 모용색은 1개의 유전자가 관여하는 것으로 나타났다. 분석결과 모용색은 연관군 C2에 위치하는 Satt134 마커와 밀접히 연관되어 있었다. 제색은 신팔달콩2호와 GC83006이 각각 흑색과 황색이었으며 후대 중에는 갈색의 배꼽을 갖고 있는 계통도 발견되었다. 종피색은 신팔달콩 2호와 GC83006이 각각 황색과 녹색을 보였으며 후대에서 황색과 녹색 계통이 1 : 1의 분리비를 보여 종피색에는 하나의 유전자가 관여하는 것으로 나타났고, 이 유전자는 연관군 D1a의 마커 Satt077과 밀접한 연관을 보였다.

• 해양환경안전학회지
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• 제20권5호
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• pp.526-534
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• 2014

본 연구는 단일 입력 전이함수모형(Single-input transfer function model)을 적용하여 여수연안 2010년의 월평균 표면수온의 예측을 시도하였다. 전이함수모형을 수립하기 위한 입력시계열과 출력시계열은 각각 여수지방의 10년(2000-2009년)간의 월평균 기온자료와 표면수온자료를 이용하였다. 전이함수모형을 수립하기 위하여 입 출력 시계열을 사전백색화하고, 입 출력 시계열간의 각 시차에 대한 교차상관함수를 결정하였다. 교차상관함수는 음의 모든 시차에서 유의한 값을 갖지 않아 기온과 표면수온사이는 일방적 인과관계를 보였다. 또한 교차상관함수의 시차 0과 1에서 유의한 값을 보였다. 이러한 교차상관함수의 특징에 따라 입 출력시계열간 전이함수의 시차와 분모 및 분자의 차수(b, r, s)는 (0, 1, 0)으로 식별되었다. 구축된 전이함수모형에 따르면 기온과 표면수온 사이의 시차는 존재하지 않았다. 여기서 현재의 표면수온은 1개월 전의 표면수온과 선형관계가 있음을 보였으며, 잡음모형은 $ARIMA(1,0,1)(2,0,0)_{12}$로 식별되었다. 전이함수모형에 의한 월평균 표면수온의 예측치는 실측치에 비하여 전반적으로 $0.3-1.3^{\circ}C$ 높은 경향을 보였으며, 6.4 %의 평균절대백분율 오차를 포함하였다. 이러한 결과는 8.3 %의 평균절대백분율오차를 보인 ARIMA 모형에 비하여 향상된 예측성능을 보이는 것이며, 표면수온의 시계열적 예측을 시도할 경우, ARIMA 모형보다 전이함수모형의 적용을 통하여 그 예측성능의 개선 가능성을 기대할 수 있음을 시사하고 있다.

• Fisheries and Aquatic Sciences
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• 제23권3호
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• pp.9.1-9.6
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• 2020

Background: Fucosterol is a compound commonly found in algae that has various biological activities. The purpose of this study was to develop a high-performance liquid chromatography (HPLC) validation method for fucosterol and to compare the fucosterol contents of 11 algal species from Ulleungdo, Korea. Method: In this study, we successfully isolated and identified fucosterol from a 70% EtOH extract of Sargassum miyabei, and subsequently conducted specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision analyses for development of an HPLC validation method. Fucosterol contents were compared using the established HPLC validation conditions. Results: We successfully isolated fucosterol from a 70% EtOH extract of S. miyabei and identified it based on spectroscopic analysis. On the basis of HPLC validation using the fucosterol isolated from S. miyabei, we confirmed specificity (8.5 min), linearity (R² = 0.9998), LOD (3.20 ㎍ mL^-1), LOQ (9.77 ㎍ mL^-1), accuracy (intra-day and inter-day variation, 90-110%), and precision (RSD, 1.07%). Fucosterol contents in the 11 assessed algal species ranged from 0.22 to 81.67 mg g^-1, with the highest content being recorded in a 70% EtOH extract of Desmarestia tabacoides (81.67 mg g^-1), followed by that of Agarum clathratum (78.70 mg g^-1). Conclusions: The results indicate that 70% EtOH extracts of D. tabacoides and A. clathratum containing fucosterol with various effects can be potential alternative sources of fucosterol.

• 한국재료학회지
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• 제25권8호
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• pp.386-390
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• 2015

Fe-base superalloy powders with $Y_2O_3$ dispersion were prepared by high energy ball milling, followed by spark plasma sintering for consolidation. High-purity elemental powders with different Fe powder sizes of 24 and 50 mm were used for the preparation of $Fe-20Cr-4.5Al-0.5Ti-O.5Y_2O_3$ powder mixtures (wt%). The milling process of the powders was carried out in a horizontal rotary ball mill using a stainless steel vial and balls. The milling times of 1 to 5 h by constant operation (350 rpm, ball-to-powder ratio of 30:1 in weight) or cycle operation (1300 rpm for 4 min and 900 rpm for 1 min, 15:1) were applied. Microstructural observation revealed that the crystalline size of Fe decreased with an increase in milling time by cyclic operation and was about 15 nm after 3 h, forming a FeCr alloy phase. The cyclic operation had an advantage over constant milling in that a smaller-agglomerated structure was obtained. The milled powders were sintered at $1100^{\circ}C$ for 30 min in vacuum. With an increase in milling time, the sintered specimen showed a more homogeneous microstructure. In addition, a homogenous distribution of Y-compound particles in the grain boundary was confirmed by EDX analysis.

• 디자인학연구
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• 제20권3호
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• pp.235-246
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• 2007

이 연구는 가정에서 그 중요성이 증가하고 있는 통합리모콘을 좀 더 쉽게 사용할 수 있도록 디자인하기 위한 것이다. 이러한 목적을 달성하기 위한 방법으로 대중성 있는 기존 제품의 UI체계를 통합리모콘의 UI체계로 적용하여 학습이 용이하고 사용성이 향상된 가정용 통합리모콘 UI디자인 대안을 개발하고 그 사용 용이성을 평가하는 연구를 진행하였다. 기존의 대중성 있는 제품으로는 UI디자인 개발 대상인 스틱형 통합리모콘과 사용방법이 유사한 휴대폰을 선정하였다. 선정한 휴대폰 UI의 공통적 특성을 도출하여 그 내용을 최대한 적용한 가정용 스틱형 통합리모콘의 디자인 안을 제작하였다. 플래시로 제작한 이 디자인 대안의 프로토타입으로 2회의 파일럿 테스트를 실시하여 최종 실험연구용 프로토타입 제작과 관련된 개선내용을 추출 하였다. 그리고 물리적인 조작, 피드백 측면에서의 사용 실제감을 보완한 버튼 프로토타입을 제작하여, 20대 대학생 41명을 대상으로 개발된 가정용 스틱형 통합리모콘의 새로운 UI디자인에 대한 사용성 평가를 진행하였다. 실험 결과 대중성 있는 기존 제품의 UI를 활용한 가정용 스틱형 통합리모콘은 사용성 향상에 기여할 수 있는 것으로 나타났으며 이 연구내용은 향후 가정용 스틱형 통합리모콘의 새로운 UI디자인 개발 연구의 좋은 모델이 될 수 있다고 판단된다.

• Journal of Forest and Environmental Science
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• 제35권4호
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• pp.240-247
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• 2019

This study quantified carbon reduction services through direct harvesting of Ilex rotunda and Machilus thunbergii, which are the typical urban landscape tree species in southern Korea. A total of 20 open-grown tree specimens (10 specimens for each species) were selected reflecting various sizes of stem diameter at breast height of 1.2 m (DBH) at a regular interval. The study measured biomass for each part of the tree specimens including roots to compute total carbon storage per tree. Annual carbon uptake per tree was also calculated analyzing the DBH growth rate of stem disk specimens. Quantitative models were developed using DBH as an independent variable to easily estimate storage and annual uptake of carbon by tree growth for each species. All the models had a high goodness-of-fit with R²=0.95-0.99. The difference in carbon reduction services between DBH sizes increased with increasing DBH. The storage and annual uptake of carbon from a tree with DBH of 10 cm were 13.5 kg and 2.4 kg/yr for I. rotunda, and 19.1 kg and 3.6 kg/yr for M. thunbergii, respectively. The tree of this size stored the amount of carbon equivalent to that emitted from a gasoline use of approximately 24 L for I. rotunda and 34 L for M. thunbergii, respectively. The study provides actual measurement data to quantify carbon reduction services of urban open-grown landscape trees for the warm-temperate species that have been little known until now.

• BMB Reports
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• 제48권1호
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• pp.42-47
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• 2015

Streptococcus mutans is frequently associated with dental caries. Bacterial fermentation of food debris generates an acidic environment on the tooth surface, ultimately resulting in tooth deterioration. Therefore, various mouthwashes have been used to reduce and prevent Streptococcus mutans. The aim of this study was to evaluate the antimicrobial activities of 4 commercial mouthwashes and those of 10% and 20% ethanol solutions (formula A, B, C, D, E and F) against Streptococcus mutans using biofilm and planktonic methods. The range of reduction in the viable cell count of Streptococcus mutans as estimated by the biofilm and planktonic methods was 0.05-5.51 log ($P{\leq}0.01$) and 1.23-7.51 log ($P{\leq}0.001$) compared with the negative control, respectively, indicating that the planktonic method had a stronger antibacterial effect against S. mutans. Among the tested formulations, formula A (Garglin $regular^{(R)}$ mouthwash) was the most effective against Streptococcus mutans ($P{\leq}0.001$).