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        검색결과 235

        121.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Yellow phosphor dispersed color conversion glasses are promising phosphor materials for white LED applications because of their good thermal durability, chemical stability, and anti-ultraviolet property. Six color conversion glasses were prepared with high Tg and low Tg specimens of glass. Luminous efficacy, luminance, CIE (Commission Internationale de l'Eclairage) chromaticity, CCT (Correlated Color Temperature), and CRI (Color Rendering Index) of the color conversion glasses were analyzed according to the PL spectrum. Color conversion glasses with high Tg glass frit, sintered at higher temperature, showed better luminous properties than did color conversion glasses with low Tg glass frit. The characteristics of the color conversion glass depended on the glass composition rather than on the sintering temperature. The XRD peaks of the YAG phosphor disappeared in the color conversion glass with major components of B2O3-ZnO-SiO2-CaO and, in the XRD results, new crystalline peaks of BaSi2O5 appeared in the color conversion glass with major components of Bi2O3-ZnO-B2O3-MgO. The characteristics of CIE chromaticity, CCT, and the CRI of low Tg color conversion glasses showed worse color properties than those of high Tg color conversion glasses. However, these color characteristics of low Tg glasses were improved by thickness variation. So color conversion glasses with good characteristics of both luminous and color properties were attained.
        4,000원
        122.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO nanorods were successfully fabricated on Zn foil by chemical bath deposition (CBD) method. The ZnO precursor concentration and immersion time affected the surface morphologies, structure, and electrical properties of the ZnO nanorods. As the precursor concentration increased, the diameter of the ZnO nanorods increased from ca. 50 nm to ca. 150 nm. The thicknesses of the ZnO nanorods were from ca. 1.98μm to ca. 2.08μm. ZnO crystalline phases of (100), (002), and (101) planes of hexagonal wurtzite structure were confirmed by XRD measurement. The fabricated ZnO nanorods showed a photoluminescene property at 380 nm. Especially, the ZnO nanorods deposited for 6 h in solution with a concentration of 0.005M showed a stronger (101) peak than they did (100) or (002) peaks. In addition, these ZnO nanorods showed a good electrical property, with the lowest resistance among the four samples, because the nanorods were densely in contact and relatively without pores. Therefore, a ZnO nanorod substrate is useful as a highly sensitive biochip substrate to detect biomolecules using an electrochemical method.
        4,000원
        123.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electrical properties of a laminated SMD type PTC thermistor for microcircuit protection were investigated as a function of polymer blowing agent addition. Green ceramics for multilayered BaTiO3-based PTCRs were formed by doctor blade method of barium titanate powders; we successfully laminated the sintered ceramic chips to obtain 10 layer chip PTCRs with PTC effect. The sintered density increases with increasing sintering temperature. The electrical properties of the sintered samples were strongly dependent on the calcination and addition of a polymer blowing agent. When BaTiO3 powders containing 0.2 mol% of Y2O3 were calcined at 1000˚C for 2 hrs, the resistivity jump was of 1-2 orders of magnitude. The resistivity at room temperature increases according to the polymer blowing agent addition. Also, the sample using the calcined powder showed a lower resistivity than that of the sample prepared using powders without calcinations. With an increase in the OBSH, the magnitude of the resistivity jumped as a function of the temperature increase. The resistivity of the sintered bodies after the addition of 0.5 wt% polymer blowing agent at 1290˚C for 2 h was shown to be about 8.5Ω·cm; the jump order of the sintered bodies was shown to be on the order of 102.
        4,000원
        124.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For the purpose of improving the durability problem, translucent opal glass was fabricated as a substitute for the polycarbonate diffuser of LED lighting. Calcium phosphate was used as an opacifier of opal glass and melted in an electric furnace. The opaque effect was identified according to the change of the cooling procedure. As results, translucent opal glass was obtained by the melting of a batch with a composition of 3.8% calcium phosphate at 1550˚C for 2 hrs and then the cooling of the material in the furnace. For the cooling condition of the glass sample, HTCG (High Temperature Cooled Glass) was found to have better optical properties than LTAG (Low Temperature Annealed Glass). It had excellent optical properties for a diffuser of LED lighting, with no dazzling from direct light due to its high haze value of over 99% and low parallel transmittance value of under 1%. For the thermal properties, it had an expressed thermal expansion coefficient of 5.7×10-6/˚C and a softening point of 876˚C; it also had good thermal properties such as good thermal shock resistance and was easy to apply to the general manufacturing process in the forming of glass tubes and bulbs. Therefore, it is concluded that this translucent opal glass can be used as a glass diffuser material for LED lighting with high heat resistance and high durability; this material is suitable as a substitute for polycarbonate diffusers.
        4,000원
        125.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the limitless competition era of the 21st century, cost reduction is being highlighted as one of survival strategies of businesses. The first item for cost reduction of businesses is logistical costs. The most keenly required thing for this is to remove unnecessary elements, and the best way to realize it to cut down processes using automatic facilities. Packing container in logistics is like a facility. This study is intended to analyze reduction of costs, improvement of business process and reduction of working force through standardization of standardization, and logistics effects through improvement of environmental images in enterprises.
        4,200원
        126.
        2012.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        TiO2 thin films consisting of positively charged poly(diallyldimethylammonium chloride)(PDDA) and negatively charged titanium(IV) bis(ammonium lactato) dihydroxide(TALH) were successfully fabricated on glass beads by a layer-by-layer(LBL) self-assembly method. The glass beads used here showed a positive charge in an acid range and negative charge in an alkaline range. The glass beads coated with the coating sequence of(PDDA/TALH)n showed a change in the surface morphology as a function of the number of bilayers. When the number of bilayers(n) of the(PDDA/TALH) thin film was 20, Ti element was observed on the surface of the coated glass beads. The thin films coated onto the glass beads had a main peak of the (101) crystal face and were highly crystallized with XRD diffraction peaks of anatase-type TiO2 according to an XRD analysis. In addition, the TiO2 thin films showed photocatalytic properties such that they could decompose a methyl orange solution under illumination with UV light. As the number of bilayers of the(PDDA/TALH) thin film increased, the photocatalytic property of the TiO2-coated glass beads increased with the increase in the thin film thickness. The surface morphologies and optical properties of glass beads coated with TiO2 thin films with different coating numbers were measured by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD) and by UV-Vis spectrophotometry(UV-vis).
        4,000원
        127.
        2012.05 구독 인증기관 무료, 개인회원 유료
        Technical Barriers to International Trade are emerging as main non-tariff barriers and so MRA is getting widespread. In addition, a significant amount in international trade occurs as intra-industry trade instead of inter-industry trade. Based on the cost reduction of testing and certification except many other effects of MRA, we compute the economic impact of MRA quantitatively. First, we use a Cournot model for intra-industry trade to compute the effect of trade balance caused by the cost reduction of testing and certification. Second, we estimate the effect on production inducement, value added inducement and employment inducement via input-output analysis.
        4,000원
        128.
        2012.04 구독 인증기관 무료, 개인회원 유료
        마산만 수괴의 물리환경이 시공간적으로 어떻게 변화하는지 알아보기 위해 수온과 염분을 관측한 결과 동계는 상대적으로 표층과 저층이 비슷한 성질의 수괴가 형성되어 수직적으로 잘 혼합될 수 있는 환경으로 나타났다. 반면 하계에는 비교적 고온이면서 많은 강수량에 의한 저염의 표층 수괴로 인해 수직적으로 뚜렷하게 분리되는 경향이 나타났다. 이러한 경향은 4월에서 9월 사이에 나타났으며 강수량이 많은 7월과 8월에 뚜렷하였는데, 강수량이 많아진 후에 강항
        3,000원
        129.
        2012.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Insoluble catalytic electrodes were fabricated by RF magnetron sputtering of Pt on Ti substrates and the performance of seawater electrolysis was compared in these electrodes to that is DSA electrodes. The Pt-sputtered insoluble catalytic electrodes were nearly 150 nm-thick with a roughness of 0.18μm, which is 1/660 and 1/12 of these values for the DSA (dimensionally stable anodes) electrodes. The seawater electrolysis performance levels were determined through measurements of the NaOCl concentration, which was the main reaction product after electrolysis using artificial seawater. The NaOCl concentration after 2 h of electrolysis with artificial seawater, which has 3.5% NaCl normally, at current densities of 50, 80 and 140 mA/cm2 were 0.76%, 1.06%, and 2.03%, respectively. A higher current density applied through the electrodes led to higher electrolysis efficiency. The efficiency reached nearly 58% in the Pt-sputtered samples after 2 h of electrolysis. The reaction efficiency of DSA showed higher values than that of the Pt-sputtered insoluble catalytic electrodes. One plausible reason for this is the higher specific surface area of the DSA electrodes; the surface cracks of the DSAs resulted in a higher specific surface area and higher reaction sites. Upon the electrolysis process, some Mg- and Ca-hydroxides, which were minor components in the artificial seawater, were deposited onto the surface of the electrodes, resulting in an increase in the electrical resistances of the electrodes. However, the extent of the increase ranged from 4% to 7% within an electrolysis time of 720 h.
        4,000원
        130.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 냉 난방공조 조건에서 예상 온열감 반응(predicted mean vote; PMV)의 변화에 따른 심리 생리적 감성반응의 변화를 살펴보고자 하였다. 이를 위해 기존 공조 시스템의 냉 난방 가동에 따라 PMV의 변화를 유도하고, 쾌/불쾌 및 각성/이완 정도를 심리적 감성반응으로, 심박률(heart rate; HR)을 생리적 감성반응으로 활용하여 PMV 변화에 따른 심리 생리적 감성반응을 측정하였다. 그 결과, 동일한 PMV 변화 범위 내에서 재실자의 심리적 쾌/불쾌 및 긴장/이완 반응과 생리적 반응이 공조 조건이 달라짐에 따라 변화하는 것으로 나타났다. 이러한 결과는 난방과 냉방의 공조조건에 따라 재실자의 실내 온열환경에 대한 감성반응이 서로 다를 뿐 아니라 각 공조 조건에 민감한 감성반응이 존재하는 것으로 해석할 수 있다. 이는 실내 온열조건을 재실자에게 가장 적합하도록 조절하고자 할 때, 인간의 심리 및 생리적 감성반응을 모두 고려해야 할 필요가 있음을 시사한다.
        4,000원
        131.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        여자만은 유기물 오염이 점차 진행되어 가고 있으며, 해역의 수질관리를 위하여 유역으로부터 유입하는 육상기인 오염물질을 GIS 기법을 이용하여 발생부하량과 배출부하량을 산정하였다. 목표수질을 달성하기 위해 해역의 환경용량을 초과하여 유입하는 육상오염물질의 양을 박스모델로 계산하여 삭감부하량과 허용유입부하량을 평가하였다. 여자만의 수질을 해역생활환경기준 I등급으로 회복하기 위한 허용부하량을 산정한 결과, 생물화학적산소요구량은 배출부하의 39.3%, 총인은 30.8%를 삭감해야 하고, 총질소의 경우 6.9%의 낮은 배출부하 삭감률을 나타내었다. 유역의 오염원 현황과 발생부하량 현황을 볼 때 토지계가 차지하는 오염부하 비중이 높고, 배출부하량에서도 가장 큰 비중을 차지하였다. 여자만의 해양환경 보호와 개선을 위해서는 육상기원 오염물질 중 점오염원 뿐만 아니라 축산계 및 토지계 부하 등 비점원 오염원에 대한 관리가 필요하다는 것을 시사한다.
        4,300원
        132.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 EFDC모델과 입자추적모델을 이용하여 마산만의 담수유입에 의한 폐쇄성 내만의 물질체류시간을 산정하였다. 마산만의 해수유동을 재현하고 이를 바탕으로 평균체류시간을 계산하였다. 마산만의 조석에 의한 평균물질체류시간은 만 북측과 돝섬 부근까지가 약 110일이내, 모도 주변 해역이 약 40일, 부도에서 외해까지 약 20일 정도로 산정되었다. 담수유입에 따른 마산만의 4개 소해역별 평균물질체류시간은 I과 II영역에서 약 81일로 감소하였으나, 마산만의 외해측에 위치한 III과 IV영역은 각각 58일과 17일로 증가하였다.
        4,000원
        133.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper deals with strength of glass fiber reinforced plastics produced by shouting machine was investigated by universal testing instrument. We can obtain following results by performing the strength evaluation of polymer composite material according as varied environment temperature. The effect of environmental temperature on Strength properties was more sensitive in the weld specimen than parent. When changed environmental temperature, variation of strength in the parent was much bigger than it of weld specimen, that is, matrix in the parent, orientation in the specimen ware more sensitive to environmental strength. Tensile strength of polycarbonate matrix was similar regardless of mold temperature.
        4,000원
        134.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Melamine has raised international concerns for its catastrophic health effects from tainted infant formula. This report concerns the developmental validation of a sensitive HPLC/MS/MS and GC/MS methods about melamine and cyanuric acid in human urine and serum. Analytical detection ranges of LC/MS was from 0.2 to 5.0 ng/mL and 2.0 to 60.0 ng/mL about melamine and cyanuric acid, respectively. The limits of quantification and confirmation are 0.2 ng/mL for both analytes in human urine and serum by LC/MS/MS. The range of recovery was 91.6%, and 107.6% for cyanuric acid and melamine in urine, respectively. The range of precision coefficient variation was from 2.0%, to 11.8% for cyanuric acid and melamine in urine. The range of recovery was from 94.9%, to 119.0% about cyanuric acid and melamine in serum, respectively. The range of precision coefficient variation from was 3.7%, and 13.5% about cyanuric acid and melamine in serum. Analytical detection ranges of GC/MS were 5.0 to 100.0 ng/mL about melamine and cyanuric acid, respectively. The limits of quantification and confirmation are 5.0 ng/mL for both analytes in human urine and serum by GC/MS. The range of recovery was from 83.7%, to 114.5% for cyanuric acid and melamine in urine, respectively. The range of precision coefficient variation was 3.5%, and 10.7% for cyanuric acid and melamine in urine. The range of recovery was 94.4%, and 110.7% for cyanuric acid and melamine in serum,respectively. The range of precision coefficient variation from was 3.9%, and 13.8% for cyanuric acid and melamine in serum. Several changes were taken to optimize performance by this method.
        5,100원
        135.
        2010.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The influences of Na and K content on the crystal phase, the microstructure and the electrical property of BaTiO3-based thermistors was found to show typical PTC effects. The crystal phase of powder calcined at 1000˚C for 4hrs showed a single phase with BaTiO3, and the crystal structure was transformed from tetragonal to cubic phase according to added amounts of Na and K. In XRD results at 43˚~47˚, the (Ba0.858Na0.071K0.071)(Ti0.9985Nb0.0015)O3-δ showed (002) and (200) peaks but the (Ba0.762Na0.119K0.119)(Ti0.9975Nb0.0025)O3-δ showed (002), (020) and (200) peaks. In sintered bodies, those calcined at 600˚C rather than at 1000˚C were dense, and for certain amounts of Na and K showed rapid decreases in grain size. In relative permittivity, the curie temperature due to the transformation of ferroelectric phase rose with added Na and K but decreased in terms of relative permittivity. In the result of the R-T curve, the sintered bodies have curie temperatures of about 140˚C and the resistivity of sintered bodies have scores of Ω·cm; the jump order of sintered bodies was shown to be more than 104 in powder calcined at 1000˚C.
        4,000원
        136.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Metabolomics aims at the comprehensive, qualitative and quantitative analysis of wide arrays of endogenous metabolites in biological samples. It has shown particular promise in the area of toxicology and drug development, functional genomics, system biology and clinical diagnosis. In this study, analytical technique of MS instrument with high resolution mass measurement, such as time-of-flight (TOF) was validated for the purpose of investigation of amino acids, sugars and fatty acids. Rat urine and serum samples were extracted by selected each solvent (50% acetonitrile, 100% acetonitrile, acetone, methanol, water, ether) extraction method. We determined the optimized liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) system and selected appropriated columns, mobile phases, fragment energy and collision energy, which could search 17 metabolites. The spectral data collected from LC/TOFMS were tested by ANOVA. Obtained with the use of LC/TOFMS technique, our results indicated that (1) MS and MS/MS parameters were optimized and most abundant product ion of each metabolite were selected to be monitorized; (2) with design of experiment analysis, methanol yielded the optimal extraction efficiency. Therefore, the results of this study are expected to be useful in the endogenous metabolite fields according to validated SOP for endogenous amino acids, sugars and fatty acids.
        4,000원
        137.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Glass was fabricated using refused coal ore obtained from the Dogye coal mine in Samcheok. We additionally used soda ash and calcium carbonate to make a glass with the chemical composition of soda-lime glass, and we also used white, brown, and green glass cullet to make various kinds of colored glass. Transparent glass was fabricated by melting batch materials including refused coal ore at 1550˚C for 1 hr in an electrical furnace. The light transmittance and color chromaticity were measured by a UV/VIS/NIR spectrometer. Transparent glass with a light transmittance of over 80% was fabricated using normal refused coal ore and white glass cullet. Various kinds of colored glass with a light transmittance of 30-80% were fabricated using refused coal ore and brown or green glass cullet. The light transmittance of the mixed color glass samples, fabricated using normal refused coal ore and brown glass cullet and green glass cullet, indicated 30-47%, a relatively low value, in the condition of a cullet ratio of 20-50%. The characteristics of the color chromaticity of the glass samples were indicated in a chromaticity diagram by x-coordinates, y-coordinates, Y (lightness). The values of x-coordinates and y-coordinates were moved with a regular directional property according to the kind and amount of glass cullet. Therefore, we concluded that refused coal ore can be used for raw materials of color glass products like art glass and glass tile.
        4,200원
        139.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자동차 시트의 만족도 평가방법은 디자인을 평가하는 방법에서부터 출발하여 완충시스템과 재료를 평가하는 기계적 방법을 지나 인간의 주관적인 감정을 평가하는 현재까지 이르렀다. 국외에서는 지난 10여 년간 자동차 시트의 만족도 평가를 위한 수많은 연구가 진행 되었고, 2006년에 설문지에 기반을 둔 통계적으로 신뢰할 만한 평가방법이 만들어져 외국에서 널리 사용되고 있다(Baba 등, 2008). 그러나 우리나라에서는 아직까지 이 방법이 활용되지 못하고 있는 실정이다. 따라서 본 연구에서는 Smith 등 (2006)의 연구방법을 중심으로 기존 연구를 분석하여 한국인에 적합한 평가 설문지를 새로 개발하였다. 6명의 자동차회사 및 시트 전문회사의 전문가들의 의견을 반영하여 기존연구에서 감성평가 항목이 중복되어 있거나 우리나라에는 적합하지 않는 항목은 제외시키고 유사한 항목들은 통합 하여 36개의 평가항목을 새로 개발하였다. 이들 항목은 유사성을 고려하여 대분류, 중분류, 소분류로 분류하였다. 36개 평가항목은 중요도가 다르기 때문에 계층화분석법(AHP)을 사용하여 평가 항목의 중요도를 결정하였다. 본 연구에서 개발된 자동차 시트 만족도 설문지는 우리나라에서 생산되는 자동차 시트의 주관적 감성 평가에 널리 활용될 수 있을 것이다.
        4,000원
        140.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구는 음식물 쓰레기를 음식물 소멸기에서 미생물에 의해 발효하여 유기물을 감량화하고, 음식물 발효시 발생되는 가스를 냉각기에서 기체와 수분으로 분리하여 기체는 반응기로 다시 보내고 수분은 응축하여 침지식 MF 중공사 분리막이 장착된 MBR 시스템에 적용하여 처리하는 시스템에 관한 연구이다. (주)바이오하이테크에서 제작한 음식물 소멸기와 수처리 장치에 침지식 MF 중공사 모듈을 설치하여 90일간 H연구소 직원식당에서 발생되는 음식물 쓰레기를 연속 투입하여 처리하였다. 음식물 소멸기 초기 Seeding를 위하여 수분조절제로 미강, 왕겨, 톱밥을 305 kg 투입하였고 음식물은 운전기간동안 1,648 kg투입하였고 응축폐수는 1,600 L 발생되었다. 음식물 소멸기 운전 종료 후 배출된 발효 부산물은 386 kg으로 감량율은 약 80%로 조사되었다. 침지식 MF 중공사 분리막 모듈을 응축폐수의 MBR 시스템에 적용하여 유기물 처리한 결과 제거율은 각각 BOD 99.9%, COD 97.5%, SS 98.6%, T-N 54.6%, T-P 34.7%였으며, 총대장균은 100%가 제거되었다.
        4,000원