• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.119-122
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• 2011

A series of mesoporous silicalites was synthesized using different compositions of tetraethylorthosilicate and methyltriethoxysilane (MTES) as the silica source. Cetyltrimethylammonium bromide was used as the organic template. Their detailed pore structures were investigated by transmission electron microscopy, X-ray diffraction, and N2 adsorption method. The thermal properties of these silicalites were studied by thermogravimetric analysis. The increased amount of MTES destroyed mesoporous channels and reduced pore sizes from 3.4 nm to 2.8 nm in calcined silicalites. The calcined silicalite transformed completely into an amorphous state at 30% MTES loading. Methyl pending groups of MTES hindered the structural ordering of ≡Si-O- frameworks, resulting in an amorphous structure. This was caused by the insufficient formation of supramolecular assembly with the organic template. No capillary condensation step was found in MS 7/3 silicalite. The other capillary condensation steps shifted toward the lower relative pressure with increasing MTES content, indicating the reduction of pore sizes.

• 한국세라믹학회지
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• 제48권5호
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• pp.360-367
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• 2011

Macroporous silicon carbide (SiC) ceramics were fabricated by powder processing and polymer processing using carbon-filled polysiloxane as a precursor. The effects of the starting SiC polytype, template type, and template content on porosity and flexural strength of macroporous SiC ceramics were investigated. The ${\beta}$-SiC powder as a starting material or a filler led to higher porosity than ${\alpha}$-SiC powder, owing to the impingement of growing ${\alpha}$-SiC grains, which were transformed from ${\beta}$-SiC during sintering. Typical flexural strength of powder-processed macroporous SiC ceramics fabricated from ${\alpha}$-SiC starting powder and polymer microbeads was 127 MPa at 29% porosity. In contrast, that of polymer-processed macroporous SiC ceramics fabricated from carbon-filled polysiloxane, ${\beta}$-SiC fillers, and hollow microspheres was 116MPa at 29% porosity. The combination of ${\alpha}$-SiC starting powder and a fairly large amount (10 wt%) of $Al_2O_3-Y_2O_3$ additives led to macroporous SiC ceramics with excellent flexural strength.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.414-414
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• 2008

Vertically well-aligned Ga-doped ZnO nanorods with different Ga contents were grown by thermal evaporation on a ZnO template. The Ga-doped ZnO nanorods synthesized with 50 wt % Ga with respect to the Zn content showed maximum compressive stress relative to the ZnO template, which led to a rapid growth rate along the c-axis due to the rapid release of stored strain energy. A further increase in the Ga content improved the conductivity of the nanorods due to the substitutional incorporation of Ga atoms in the Zn sites based on a decrease in lattice spacing. The p-n diode structure with Ga-doped ZnO nanorods, as a n-type, displayed a distinct white light luminescence from the side-view of the device, showing weak ultraviolet and various deep-level emissions.

• 한국전기전자재료학회논문지
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• 제23권9호
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• pp.741-746
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• 2010

Three-dimensionally ordered macro-porous Sn-C composites were prepared by using polystyrene microsphere as a template. The Sn-C composites were composed of well-interconnected pore with circular shape and wall structure with wall thickness of a few tens of nano-meters. This porous three-dimensional structure is readily and uniformly accessible to the electrolyte, which facilitates lithium ion diffusion during charge-discharge reactions. The wall thickness of the composites was increased as the increase of Sn content of the composite. From EDS analysis, it is confirmed that the Sn was dispersed uniformly in Sn-C composites. The capacity was increased as the Sn content increased, which is due to Sn anode with high capacity. The Sn-C composites with high Sn content showed superior cyclic performances. Such enhancement is ascribed to the thick wall thickness and small pore size of the sample with high Sn content. The Sn-C composite with Sn 30 wt% showed relatively high capacity and stable cycle life, however, the stability of the 3-dimensional structure should be enhanced by further work.

• 중환자간호학회지
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• 제3권2호
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• pp.61-76
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• 2010

Purpose: This study was aimed to construct an algorithm of dyspnea emergency care and develop a simulation scenario for emergency care of dyspnea based on the algorithm. Methods: The first stage of this methodological study was to construct a preliminary algorithm based on a literature review, and content and clinical validity were established. Reflecting the result of content and clinical validity for this preliminary algorithm, simulation scenario was developed based on the modified Bay Area Simulation Collaborative scenario template. The content validity of this scenario was established, and clinical applicability was tested by applying this scenario to nurses. Results: The final simulation scenario of emergency care of dyspnea consisted of scenario overview, curricular integrity, and scenario script. The scenario was proceeded on 7 phases of the algorithm as follows; initial assessment, immediate emergency care, reassessment of dyspnea, monitoring respiratory failure, checking pulse if respiratory failure occurs, decision making on cardiopulmonary resuscitation or intubation, determining a differential diagnosis according to origin of dyspnea. Conclusion: The simulation scenario of emergency care of dyspnea developed in this study may provide a strategy of simulation education for emergency care of dyspnea for nurses.

• 산업식품공학
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• 제14권1호
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• pp.49-53
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• 2010

표면 플라즈몬 공명을 이용한 센서는 굴절계 기기의 일종으로서 높은 감도를 가질 뿐만 아니라 비표지 방식이라는 장점을 가지고 있다. 본 연구에서는 재래식 SPR 칩을 이용하여 시판 술 4종의 알코올 함량을 측정하였다. 또한, 재래식 SPR 칩의 감도를 개선하기 위하여 금 박막 위에 금으로 나노형상을 구축하여 나노형상 SPR 칩을 제조하여 모형 술에 대한 감도 개선 효과를 분석하였다. 재래식 SPR 칩을 이용하여 시판 술의 알코올 함량을 측정하기 위한 검량선을 개발하였을 때 시료를 전처리 하지 않고 그대로 측정하였을 때 가장 좋은 검량선을 얻을 수 있었다. 소주, 청주, 이과두주, 탁주 등 시판 술 4종에 대한 1차 회귀식의 검량식에서 결정계수는 각각 0.992, 0.933, 0.918, 그리고 0.984로 나타났다. 한편, 재래식 SPR 칩의 감도를 개선하기 위해 나노형상 SPR 칩을 제조하기 위하여 Langmuir-Blodgett(LB) 방법을 활용하였다. 본 연구에서는 수십 nm 두께의 금 박막을 바닥층으로 하여 그 위에 나노 크기의 실리카 입자를 단분자 층으로 덮어 형틀을 제조하고 다시 그 위에 금을 증착한 후 실리카 입자를 제거하는 방법으로 나노형상을 갖는 SPR 칩을 제조하였다. 나노형상 SPR 칩의 성능을 평가하였을 때 20% 알코올 함량을 가지는 모형 술에 대해서 바닥층의 두께가 50 nm, 나노형상에서 골의 깊이가 20 nm, 나노형상의 배열주기가 300 nm일 때 SPR의 감도가 가장 좋아서 95%의 감도 향상을 얻을 수 있었다. SPR의 감도는 칩과 관련된 인자, 시료의 종류 및 상태에 따라 다르게 나타날 수 있으므로 측정 목적에 알맞은 칩의 설계와 선택이 요구된다.

• 한국재료학회지
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• 제20권11호
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• pp.592-599
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• 2010

A porous nickel-tin nano-dendritic electrode, for use as the anode in a rechargeable lithium battery, has been prepared by using an electrochemical deposition process. The adjustment of the complexing agent content in the deposition bath enabled the nickel-tin alloys to have specific stoichiometries while the amount of acid, as a dynamic template for micro-porous structure, was limited to a certain amount to prevent its undesirable side reaction with the complexing agent. The ratios of nickel to tin in the electro-deposits were nearly identical to the ratios of nickel ion to tin ion in the deposition bath; the particle changed from spherical to dendritic shape according to the tin content in the deposits. The nickel to tin ratio and the dendritic structure were quite uniform throughout the thickness of the deposits. The resulting nickel-tin alloy was reversibly lithiated and delithiated as an anode in rechargeable lithium battery. Furthermore, the resulting anode showed much more stable cycling performance up to 50 cycles, as compared to that resulting from dense electro-deposit with the same atomic composition and from tin electrodeposit with a similar porous structure. From the results, it is expected that highly-porous nickel-tin alloys presented in this work could provide a promising option for the high performance anode materials for rechargeable lithium batteries.

• 한국콘텐츠학회논문지
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• 제14권2호
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• pp.28-38
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• 2014

서양 음악의 경우 자동채보와 내용기반 음악검색을 위한 음악 정보 분석연구가 활발하게 진행되고 있다. 그러나 한국 전통음악에서는 유사한 연구사례를 찾아보기 어렵다. 본 논문에서는 한국의 전통음악인 판소리 구조를 자동으로 분석하기 위한 알고리즘들을 제안한다. 제안된 알고리즘은 음성과 비음성의 시간 간격비율을 이용하여 '소리' 부분과 '아니리' 부분을 자동으로 구분한다. 뿐만 아니라 알고리즘은 '장단'이라 칭하는 리듬을 템플릿 이용한 다수결 결정 방법으로 강건하게 구분한다. 또한 알고리즘은 칼만 필터를 이용하여 '소리' 부분의 마디 지점을 검지해낸다. 본 논문에서 제안된 알고리즘들은 판소리 샘플들에서 양호하게 동작하였으며 자동채보의 전단계의 구조분석에 유용할 수 있다.

• Carbon letters
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• 제28권
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• pp.116-120
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• 2018

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature ($600-850^{\circ}C$) on the $CO_2$ adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of $1488m^2g^{-1}$ was achieved at an activation temperature of $800^{\circ}C$ (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to $850^{\circ}C$. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, $CO_2$ adsorption isotherms showed that AC-800 exhibited the best $CO_2$ adsorption capacity of $110mg\;g^{-1}$ at 298 K and 1 bar.

• 한국가정과교육학회지
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• 제27권2호
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• pp.95-119
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• 2015

본 연구는 백워드 디자인에 대한 이해를 도모하고, 백워드 디자인에 기초한 소비단원 설계의 사례를 제시하는 데에 연구의 목적을 두었다. 이 목적을 달성하기 위하여 백워드 디자인을 개발한 Wiggins와 McTighe의 여러 문헌과 관련 선행연구에 기초하여 백워드 디자인의 수행과 평가를 강조하는 특징, 이해의 개념 및 영속적 이해의 개념에 대해 중점적으로 논의하고, 3단계로 이루어진 백워드 디자인 템플릿을 적용하여 7차시로 구성된 소비 단원을 위한 수업 모듈을 개발하였다. 백워드 디자인은 다음과 같이 기여할 수 있을 것으로 판단된다. 첫째, 성취평가제의 도입과 더불어 백워드 디자인의 선평가-후수업 설계의 흐름은 학생들의 높은 성취를 얻을 수 있는 데에 기여할 수 있다. 둘째, 백워드 디자인은 단원의 핵심 개념을 분석하여 고차적 지식과 기능으로 학습이 이루는 데에 기여할 수 있다. 셋째, 교과서의 단원구성은 차시별 지도안을 계획하기에 적합하게 구성되어 있지만 백워드 디자인은 학교의 상황과 맥락을 고려하고 교사의 관점과 학생의 요구에 기초하여 학습 내용을 재구성하는 데에 기여할 수 있다.