검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 4,701

        2241.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to give information on e-CPC implementation in the manufacturing industry by studying and analyzing a small and medium sized manufacturing company. After analyzing Various factors on J’s e-CPC implementation such as environmen
        4,000원
        2242.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents a novel single-step method to prepare the Ag nanometallic particle dispersed fluid (nanofluid) by electrical explosion of wire in liquid, deionized water (DI water). X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) were used to investigate the characteristics of the Ag nanofluids. Zeta potential was also used to measure the dispersion properties of the as-prepared Ag nanofluid. Pure Ag phase was detected in the nanofluids using water. FE-SEM analysis shows that the size of the particles formed in DI water was about 88 nm and Zeta potential value was about -43.68 without any physical and chemical treatments. Thermal conductivity of the as-prepared Ag particle dispersed nanofluid shows much higher value than that of pure DI water.
        4,000원
        2243.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Eu red phosphor was prepared by microwave synthesis. The crystal phase, particle morphology, and luminescent properties were characterized by XRD, SEM, and spectrofluorometer, respectively. The prepared :Eu particles had good crystallinity and strong red emission under ultravioletet excitation. The crystallite size increased with calcination temperature and satuarated at . The primary particle size initially formed was varied from 30 to 450 nm with microwave-irradiation (MI) time. It was found that the emission intensity of :Eu phosphor strongly depends on the MI time. In terms of the emission intensity, it was recommended that the MI time should be less than 15 min. The emission intensity of :Eu phosphor prepared by microwave syntehsis strongly depended on the crystallite size of which an optimal size range was 50-60 nm
        4,000원
        2244.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A visible-light photoactive photocatalyst was synthesized successfully by means of cogrinding of anatase- in ambient, followed by heat-treatment at in air environment. In general, it is well known that the grinding-operation induces phase transformation of a- to rutile . This study investigates the influence of the amount of gas on the phase transformation rate of a- and enhancement of visible-light photocatalytic activity, and also examines the relation between the photocatalytic activity and the period of grinding time. The phase transformation rate of a- to rutile is retarded with the amount of NH3 injected. And the visible-light photocatalytic activity of samples, was more closely related to the period of grinding time than amount injected, which means that the doping amount of nitrogen into more effective to mechanical energy than amount injected. XRD, XPS, FT-IR, UV-vis, Specific surface area (SSA), NOx decomposition techniques are employed to verify above results more clearly.
        4,000원
        2245.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The calcination and hydrogen-reduction behavior of Fe- and Ni-nitrate have been investigated. /NiO composite powders were prepared by chemical solution mixing of Fe- and Ni-nitrate and calcination at for 2 h. The calcined powders were hydrogen-reduced at for 30 min. The calcination and hydrogen-reduction behavior of Fe- and Ni-nitrate were analyzed by TG in air and hydrogen atmosphere, respectively. TG and XRD analysis for hydrogen-reduced powders revealed that the /NiO phase transformed to phase at the temperature of . The activation energy for the hydrogen reduction, evaluated by Kissinger method, was measured as 83.0 kJ/mol.
        4,000원
        2249.
        2009.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Mn-substituted BiFeO3(BFO) thin films were prepared by r.f. magnetron sputtering under an Ar/O2mixture of various deposition pressures at room temperature. The effects of the deposition pressure andannealing temperature on the crystallization and electrical properties of BFO films were investigated. X-raydiffraction patterns revealed that BFO films were crystallized for films annealed above 500oC. BFO filmsannealed at 550oC for 5 min in N2 atmosphere exhibited the crystallized perovskite phase. The (Fe+Mn)/Biratio decreased with an increase in the deposition pressure due to the difference of sputtering yield. The grainsize and surface roughness of films increased with an increase in the deposition pressure. The dielectricconstant of BFO films prepared at various conditions shows 127~187at 1kHz. The leakage current densityof BFO films annealed at 500oC was approximately two orders of magnitude lower than that of 550oC. Theleakage current density of the BFO films deposited at 10~30m Torr was about 5×10-6~3×10-2A/cm2 at 100kV/cm. Due to the high leakage current, saturated P-E curves were not obtained in BFO films. BFO film annealedat 500oC exhibited remnant polarization(2Pr) of 26.4µC/cm2 at 470kV/cm.
        4,000원
        2250.
        2009.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electrocatalytic behavior of the PtCo catalyst supported on the multi-walled carbon nanotubes (MWNTs) has been evaluated and compared with commercial Pt/C catalyst in a polymer electrolyte membrane fuel cell(PEMFC). A PtCo/MWNTs electrocatalyst with a Pt:Co atomic ratio of 79:21 was synthesized and applied to a cathode of PEMFC. The structure and morphology of the synthesized PtCo/MWNTs electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. As a result of the X-ray studies, the crystal structure of a PtCo particle was determined to be a face-centered cubic(FCC) that was the same as the platinum structure. The particle size of PtCo in PtCo/MWNTs and Pt in Pt/C were 2.0 nm and 2.7 nm, respectively, which were calculated by Scherrer's formula from X-ray diffraction data. As a result we concluded that the specific surface activity of PtCo/MWNTs is superior to Pt/C's activity because of its smaller particle size. From the electrochemical impedance measurement, the membrane electrode assembly(MEA) fabricated with PtCo/MWNTs showed smaller anodic and cathodic activation losses than the MEA with Pt/C, although ohmic loss was the same as Pt/C. Finally, from the evaluation of cyclic voltammetry(CV), the unit cell using PtCo/MWNTs as the cathode electrocatalyst showed slightly higher fuel cell performance than the cell with a commercial Pt/C electrocatalyst.
        4,000원
        2251.
        2009.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        천연조미소재 개발을 위하여 고압/효소분해 시스템에서 멸치 단백질의 분해 품질특성을 탐색한 결과, 최적 조건은 효소농도 0.6%, 온도 50oC, 처리시간 24시간 및 압력 50 MPa로 확인되었다. 멸치 단백질의 처리방법에 따른 품질특성을 비교한 결과, 최적조건하에서 고압/효소 처리한 멸치 가수분해물의 품질특성이 가열추출물인 대조구에 비하여 2.8배, 2배, 1.4배 증가하여 고압/효소 처리에 의한 단백질 가수분해물 생산은 가열추출법이나 고압반응에 비하여 효율적인 방법으로 나타났다. 효소종류에 따른 분해력은 복합효소로 가수분해한 경우 상업효소에 비하여 큰 증가율을 나타내어 복합효소의 분해력이 상업효소에 비하여 우수하였다. 고압/효소 처리 후의 멸치 가수분해물은 정미성 아미노산으로 알려져 있는 glutamic acid, glycine, arginine 및 alanine 등의 함량이 대조구나 압력 처리구의 유리아미노산 함량에 비하여 증가하였다. 결론적으로 고압/효소분해 처리공정은 멸치 단백질의 효과적 분해와 정미성 아미노산 생산에 효율적인 기술임을 확인하였다.
        4,000원
        2252.
        2009.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        딸기 분말의 대체량을 0-6%로 달리하여 쿠키를 제조한 후 물리화학적 품질특성을 측정하고 각 특성사이의 상관관계를 살펴보았다. 딸기 분말 대체량이 증가함에 따라 반죽의 pH와 쿠키의 경도는 유의적으로 감소하였다(p<0.05). 반죽의 수분함량은 딸기 분말의 대체에 따라 유의적인 차이를 나타내지는 않았지만 평균 수분함량은 증가하는 경향을 나타내었다. 딸기 분말의 대체량이 증가할수록 명도와 황색도는 유의적으로 감소한 반면 적색도는 증가하였다(p<0.05). 퍼짐성 지수 역시 유의적인 증가를 나타내었다(p<0.05). 한편 상관분석결과 딸기 분말 대체수준은 모든 물리화학적 품질특성과 유의적인 상관관계를 나타내었다. 또한 반죽의 수분함량과 퍼짐성 지수 사이에 양의 유의적 상관관계가 관측되었다(p<0.05).
        4,000원
        2253.
        2009.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Carbon nanotubes (CNT) were used as a catalyst support where catalytically active Pd and Pt metalparticles decorated the outside of the external CNT walls. In this study, Pd and Pt nanoparticles supportedon HNO3-treated CNT were prepared by microwave-assisted heating of the polyol process using PdCl2 andH2PtCl6•6H2O precursors, respectively, and were then characterized by SEM, TEM, and Raman. Ramanspectroscopy showed that the acid treated CNT had a higher intensity ratio of ID/IG compared to that of non-treated CNT, indicating the formation of defects or functional groups on CNT after chemical oxidation.Microwave irradiation for total two minutes resulted in the formation of Pd and Pt nanoparticles on the acidtreated CNT. The sizes of Pd and Pt nanoparticles were found to be less than 10nm and 3nm, respectively.Furthermore, the SnO2 films doped with CNT decorated by Pd and Pt nanoparticles were prepared, and thenthe NO2 gas response of these sensor films was evaluated under 1~5ppm NO2 concentration at 200oC. It wasfound that the sensing property of the SnO2 film sensor on NO2 gas was greatly improved by the addition ofCNT-supported Pd and Pt nanoparticles.
        4,000원
        2254.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Austenitic oxide-dispersion-strengthened (ODS) stainless steel was fabricated using a wet mixing process without a mechanical milling in order to reduce contaminations of impurities during their fabrication process. Solution of yttrium nitrate was dried after a wet mixing with 316L stainless steel powder. Carbon and oxygen contents were effectively reduced by this wet processing. Microstructural analysis showed that coarse yttrium silicates of about 150 nm were formed in austenitic ODS steels with a silicon content of about 0.8 wt%. Wet-processed austenitic ODS steel without silicon showed higher yield strength by the presence of finer oxide of about 20 nm.
        4,000원
        2255.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of thermal treatment conditions on ADU (ammonium diuranate) prepared by SOL-GEL method, so-called GSP (Gel supported precipitation) process, were investigated for kernel preparation. In this study, ADU compound particles were calcined to particles in air and Ar atmospheres, and these particles were reduced and sintered in 4%-/Ar. During the thermal calcining treatment in air, ADU compound was slightly decomposed, and then converted to phases at . At , the phase appeared together with . After sintering of theses particles, the uranium oxide phases were reduced to a stoichiometric . As a result of the calcining treatment in Ar, more reduced-form of uranium oxide was observed than that treated in air atmosphere by XRD analysis. The final phases of these particles were estimated as a mixture of and .
        4,000원
        2256.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mechanical coating process was applied to form 89 %-hydrolyzed poly vinyl alcohol (PVA) onto boron carbide (B4C) nanopowder using one step high energy ball mill method. The polymer layer coated on the surface of B4C was changed to glass-like phase. The average particle size of core/shell structured B4C/PVA was about 50 nm. The core/shell structured B4C/PVA was formed by dry milling. However, the hydrolyzed PVA of 98~99% with high glass transition temperature (Tg) was rarely coated on the powder. The Tg of polymer materials was one of keys for guest polymer coating on to the host powder by solvent free milling.
        4,000원
        2257.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanopowders of and FeAl were fabricated by high energy ball milling. Dense 4.25 composite was simultaneously synthesized and consolidated by high frequency induction heated combustion method within 2 min from mechanically activated powders. Consolidation was accomplished under the combined effects of a induced current and mechanical pressure of 80 MPa.
        4,000원
        2258.
        2009.04 구독 인증기관 무료, 개인회원 유료
        Using the Malmquist productivity index, this paper compares the productivity of Korean manufacturing industries from 1999 to 2006. The malmquist productivity index has more advantages than previous methods such as solow model, endogenous growth theory. The malmquist productivity index can be decomposed productivity into two parts. The first part is an index of the technical efficiency change. This index has high value when the elements of production is used more efficiently. The second part is an index of technical change. This index has high value if the advent of new technology and process innovation occur.
        4,600원
        2259.
        2009.04 구독 인증기관 무료, 개인회원 유료
        Recently Environmental issues is Product development for ease of disassembly and recycling requires methodical toolboxes and respective infrastructures of information and communication technology. Therefore, today's designers have a very high level of product responsibility as disassembly is a major cost factor of product recycling. A study on the product redesign Methods and tools for sustainable management.
        4,000원
        2260.
        2009.04 구독 인증기관 무료, 개인회원 유료
        본 연구는 직무 스트레스와 근골격계질환과의 관련성을 알아보기 위하여 단순작업과 반복 작업이 빈번하게 발생하는 전자제품 제조업에 대하여 고용 규모 30인 미만과 300인 이상의 사업장을 구분하여 실시하였다. 연구 대상자 311명은 근골격계질환 관련 자각증상과 한국인 직무 스트레스(KOSS)에 대해 설문 조사 방법을 이용하여 분석하였으며, 그 결과 한국인 직무스트레스(KOSS)영역에서 30인 이하의 사업장이 물리적환경, 직무요구, 직무자율성결여, 직무불안정, 조직체계, 보상부적절, 직장문화의 영역에서 불만족도가 300인 이상사업장에 비하여 스트레스가 높게 나타났다. 근골격계질환 관련 신체 부위별 증상자를 살펴보면 신체부위 목, 허리에 대한 증상 호소자가 가장 많은 것으로 나타났으며, 근로자들이 근무중 회사와의 갈등으로 격는 한국인 직무스트레스(KOSS)에서는 물리적환경, 직무요구, 직무자율성결여, 직무불안정, 조직체계, 보상부적절, 직장문화에 대하여 30인 미만 사업장 소속 근로자들의 스트 레스 노출정도가 높았다. 다만 KOSS부분에서 근로자들의 개인적인 성향을 나타내는 관계갈등부분은 약간의 차이로 300인 이상 고용사업장의 근로자에 대한 스트레스 노 출정도가 높았다. 이에 30인 미만 사업장과 같은 영세업종 근로자들에게 정신사회적 스트레스의 해소를 위한 예방 프로그램이 마련되어야 할 것이다.
        4,300원