• 한국과학교육학회지
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• 제15권1호
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• pp.39-53
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• 1995

The purpose of this study was development of 'Environmental Science' of high school appropriate to Sixth Natinal Education Curriculum. In view that ultimate aim of environmental education is forming responsible environmental behaviors and the goals of values and behaviors are as important as knowledges and skills, A new environmental text of high school level was developed and it was based on analysis of seven texts and environmental education in Fifth Korean Curriculum. This text have seven units, 1.Habitates : What're the Meanings?, 2.Nuclear Energy: Can't be Avoid?, 3.Acid Rain : What're the Messages", 4.Ethanol : Is this Future Fuel?, 5.Wastes : A New War!, 6.What're the National and Global Environmental Issues? and 7.Our Water: Can Drink, Really? This text was stressed equally in goals of four environmental education and avoided from the array of knowledges. Therefore included various teaching strategies and independent actions of students. 'Open-ended value learning' and 'free behavior learning' in text were special learning parts for aquisition of values and formation of behaviors. To verify the effects of new developed environmental text, the direct learning was carried out by 286 students in total. Post test scores of experimental groups per each units were significantly higher than those of control groups about four goals, respectively. The Results of questionnaires by 50 teachers from five different schools were as follows. For validity of selecting contents for units, 74% of respondents replied positively. For classification and presentation of four goal-groups, 90% replied positively in validity and 82%, in utility. For validity of various teaching strategies, 88% and for the degree of including student-centered independent actions, 86% replied positively. For importances and expected effects of 'open-ended value learning' and 'free behavior learning', showed positive responses respectively, 88%, 92%. Therefore this text is effective to acheive four goals of environmental education equally.

• 대한인간공학회지
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• 제29권3호
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• pp.383-391
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• 2010

The present study evaluated a preliminary control room (CR) design of radioactive waste facility using the $JACK^{(R)}$ human simulation system. Four digital humanoids ($5^{th}$, $50^{th}$, $95^{th}$, and $99^{th}$ percentiles) were used in the ergonomic evaluation. The first three were selected to represent 90% of the target population (Korean males aged 20 to 50 years) and the last to reflect the secular trend of stature for next 20 years in South Korea. The preliminary CR design was assessed by checking its compliance to ergonomic guidelines specified in NUREG-0700 and conducting an in-depth ergonomic analysis with a digital prototype of the CR design and the digital humanoids in terms of postural comfort, reachability, visibility, and clearance. For identified design problems, proper design changes and their validities were examined using JACK. A revised CR design suggested in the present study would contribute to effective and safe operations of the CR as well as operators' health in the workplace.

• 대한기계학회논문집
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• 제12권3호
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• pp.520-527
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• 1988

본 연구에서는 액체용 이젝터의 성능을 결정하는 여러가지 제약인자중 특히 레이놀즈수 변화에 따른 구동노즐의 면적비 및 목부길이가 액체용 이제터성능에 미치 는 영향을 체계적인 실험을 통하여 연구함으로써 기 개발된 CAD용 전산프로그램의 타 당성을 보다 세밀히 검토하고 이에 보완을 가하는데 연구의 목적이 있다.

• BMB Reports
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• 제36권2호
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• pp.207-213
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• 2003

Peroxisome proliferator-activated receptors (PPARs) are orphan nuclear hormone receptors that are known to control the expression of genes that are involved in lipid homeostasis and energy balance. PPARs activate gene transcription in response to a variety of compounds, including hypolipidemic drugs. Most of these compounds have high affinity to the ligand-binding domain (LBD) of PPARs and cause a conformational change within PPARs. As a result, the receptor is converted to an activated mode that promotes the recruitment fo co-activators such as the steroid receptor co-activator-1 (SRC-1). Based on the activation mechanism of PPARs (the ligand binding to $PPAR{\gamma}$ induces interactions of the receptor with transcriptional co-activators), we performed Western blot and ELISA. These showed that the indomethacin, a $PPAR{\gamma}$ ligand, increased the binding between $PPAR{\gamma}$ and SRC-1 in a ligand dose-dependent manner. These results suggested that the in vitro conformational change of $PPAR{\gamma}$ by ligands was also induced, and increased the levels of the ligand-dependent interaction with SRC-1. Collectively, we developed a novel and useful ELISA system for the mass screening of $PPAR{\gamma}$ ligands. This screening system (based on the interaction between $PPAR{\gamma}$ and SRC-1) may be a promising system in the development of drugs for metabolic disorders.

• 생물정신의학
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• 제5권1호
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• pp.66-70
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• 1998

Apoptosis is a form of cell death in which the cells shrink and exhibit nuclear chromatin condensation and DNA fragmentation, and yet maintain membrane integrity. Many lines of evidence have shown that brain neurons are vulnerable to degeneration by apoptosis. Also it has been suggested that apoptosis is one of the mechanism contributing neuronal loss in Alzheimer's disease(AD), since the conditions in the disease($A{\beta}$ peptide, oxidative stress, low energy metabolism) are the inducers that activate apoptosis. Indeed some neurons in vulnerable regions of the AD brain show DNA damage, chromatin condensation, and apoptic bodies. Consistently, mutations in AD causative genes(Amyloid precursor protein, Presenilin-1 and Presenilin- 2) increase $A{\beta}$ $peptide_{1-42}(A{\beta}_{1-42})$ and sensitize neuronal cell to apoposis. However, several lines of evidence have shown that the location of neuronal loss and $A{\beta}$ peptide deposition is not correlated in AD brain and transgenic mice brain over-expressing $A{\beta}_{1-42}$. Taken together, these data may indicated that $A{\beta}$ peptide(and other causative factors of AD) can interact with other cellular insults or risk factors to exacerbate pathological mechansim of AD through apoptosis. Thus, this review discusses possible role and mechanism of apoptosis in AD.

• Toxicological Research
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• 제21권4호
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• pp.279-284
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• 2005

We have screened the cytoprotective effect against $H_2O_2$ and $\gamma-ray$ radiation induced oxidative stress from 32 Korean plants. Betula ermani var.saitoana (caulis, leaves), Rosa wichuraiana (caulis), Sorbus commixta (caulis), Weigela florida (leaves), Cirsium rhinoceros (whole plant), and Viburnum erosum (caulis) were found to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and intracellular reactive oxygen species (ROS). As a result, extracts of six plants reduced cell death of Chinese hamster lung fibroblast (V79-4) cells induced by $H_2O_2$ treatment. In addition, these extracts protected cell death of V79-4 cells damaged by $\gamma-ray$ radiation. In addition, these extracts scavenged ROS generated by radiation. Taken together, the results suggest that Betula ermani var. saitoana, Rosa wichuraiana, Sorbus commixta, Weigela florida, Cirsium rhinoceros, and Vibumum erosum protect V79-4 cells against oxidative damage by radiation through scavenging ROS.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2505-2511
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• 2014

Indium oxide nanocrystals ($In_2O_3$ NCs) with sizes of 5.5 nm-10 nm were synthesized by hot injection of the mixture precursors, indium acetate and oleic acid, into alcohol solution (1-octadecanol and 1-octadecence mixture). Field emission transmission electron microscopy (FE-TEM), High resolution X-Ray diffraction (X-ray), Nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FT-IR) were employed to investigate the size, surface molecular structure, and crystallinity of the synthesized $In_2O_3$ NCs. When covered by oleic acid as a capping group, the $In_2O_3$ NCs had a high crystallinity with a cubic structure, demonstrating a narrow size distribution. A high mobility of $2.51cm^2/V{\cdot}s$ and an on/off current ratio of about $1.0{\times}10^3$ were observed with an $In_2O_3$ NCs thin film transistor (TFT) device, where the channel layer of $In_2O_3$ NCs thin films were formed by a solution process of spin coating, cured at a relatively low temperature, $350^{\circ}C$. A size-dependent, non-monotonic trend on electron mobility was distinctly observed: the electron mobility increased from $0.43cm^2/V{\cdot}s$ for NCs with a 5.5 nm diameter to $2.51cm^2/V{\cdot}s$ for NCs with a diameter of 7.1 nm, and then decreased for NCs larger than 7.1 nm. This phenomenon is clearly explained by the combination of a smaller number of hops, a decrease in charging energy, and a decrease in electronic coupling with the increasing NC size, where the crossover diameter is estimated to be 7.1 nm. The decrease in electronic coupling proved to be the decisive factor giving rise to the decrease in the mobility associated with increasing size in the larger NCs above the crossover diameter.

• 한국지진공학회논문집
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• 제15권6호
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• pp.11-18
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• 2011

원자력발전소(이하, 원전)에 설치되는 안전관련 전기기기들의 합리적인 내진검증을 위해서는 사전에 정확한 동특성분석이 필요하다. 이 연구에서는 원전에 설치되는 전기기기 캐비닛 구조를 대상으로 입력 진동의 수준에 따른 모드특성의 변화를 평가하였다. 이를 위해, 실제 전기기기 캐비닛을 시편으로 선정하고 가진 시험기를 이용하여 입력진동에너지의 크기를 변화시켜 가면서 진동시험을 수행하였다. 시험은 캐비닛의 문짝을 부착한 경우와 탈거한 경우로 구분하여 수행하였다. 진동시험을 통하여 계측된 시편의 가속도응답신호와 입력운동신호로부터 진동의 크기에 따라 진동수응답함수를 작성하였다. 다항식회귀분석기법을 이용한 모드분석기법으로 시편의 진동수응답함수를 분석하여 모드특성을 추출하고, 진동수준에 따른 시편의 동특성 변화를 검토하였다. 연구결과, 대상 기기는 입력진동의 크기가 증가할수록 모드진동수와 모드감쇠비가 비선형적으로 변화하는 것을 확인하였다. 문짝이 부착된 경우에는 문짝이 탈거된 경우에 비하여 캐비닛의 모드감쇠가 증가한다.

• 대한교통학회지
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• 제33권1호
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• pp.90-99
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• 2015

우리나라는 지리적으로 중위도 온대성 기후대에 해당하며, 초여름부터 초가을까지 집중호우가 발생한다. 집중호우는 도로의 용량 및 서비스 수준에 직접적인 영향을 미치며, 이에 대한 분석의 필요성이 대두되었다. 본 연구는 신호교차로에서의 강우에 따른 포화교통류율 변화를 측정하여 강우가 도로용량에 미치는 영향을 분석하였다. 이를 위해 영상자료를 구축하였고, 영상의 프레임분석을 시행하여 차두간격을 조사하였으며, 조사된 결과를 바탕으로 포화교통류율을 산정하였다. 분석결과에 따르면 일반적인 기상상황에 비해 강우상황에는 포화차두시간이 증가하는 것을 확인하였으며 시간당 강우량이 증가함에 따라 포화교통류율이 점차 감소하는 것을 통계적으로 검정하였다. 통계적 검정 결과 일정 시간당 강우량 범위 내에서는 포화교통류율의 변화가 크지 않으므로 각 시간당 강우량의 범위에 따라 세 영역으로 분류하였으며 각 영역에 따라 포화교통류율은 약 7%, 17%, 21% 감소하는 것으로 나타났다.

• Progress in Superconductivity
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• 제6권2호
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• pp.133-137
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• 2005

We fabricated the Au/Ni template for YBCO coated conductors and evaluated texture formation and the microstructural evolution. The cube textured Ni substrate was fabricated by rolling and recrystallization annealing, and subsequently Au layer formed on the substrate by electroless-plating method. The texture was evaluated by pole-figure with x-ray goniometer with orientation distribution function (ODF) analysis. The surface roughness and grain boundary morphology of template were characterized by atomic force microscopy (AFM) We observed that Au layer deposited epitaxially on Ni substrate and formed a strong cube texture when plating time was optimized. The full-width at half-maximum (FWHM) was $8.4^{\circ}$ for out-of-plane and $9.98^{\circ}$ for in-plane texture for plating time of 30 min. Microstructural observation showed that the Au layer was homogeneous and dense without formation of crack/microcrack. In addition, we observed that root-mean-square (RMS) and depth of grain boundary were 14.6 nm and 160 $\AA$ for the Au layer, respectively, while those were 27.0 nm and 800 $\AA$ for the Ni substrate, indicating that the electoless-plated Au layer had relatively smooth surface and effectively mollified grain groove.