검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 19

        1.
        2024.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, NASICON-type Li1+XGaXTi2-X(PO4)3 (x = 0.1, 0.3 and 0.4) solid-state electrolytes for all-solid-state batteries were synthesized through the sol-gel method. In addition, the influence on the ion conductivity of solid-state electrolytes when partially substituted for Ti4+ (0.61Å) site to Ga3+ (0.62Å) of trivalent cations was investigated. The obtained precursor was heat treated at 450 °C, and a single crystalline phase of Li1+XGaXTi2-X(PO4)3 systems was obtained at a calcination temperature above 650 °C. Additionally, the calcinated powders were pelletized and sintered at temperatures from 800 °C to 1,000 °C at 100 °C intervals. The synthesized powder and sintered bodies of Li1+XGaXTi2-X(PO4)3 were characterized using TGDTA, XRD, XPS and FE-SEM. The ionic conduction properties as solid-state electrolytes were investigated by AC impedance. As a result, Li1+XGaXTi2-X(PO4)3 was successfully produced in all cases. However, a GaPO4 impurity was formed due to the high sintering temperatures and high Ga content. The crystallinity of Li1+XGaXTi2-X(PO4)3 increased with the sintering temperature as evidenced by FE-SEM observations, which demonstrated that the edges of the larger cube-shaped grains become sharper with increases in the sintering temperature. In samples with high sintering temperatures at 1,000 °C and high Ga content above 0.3, coarsening of grains occurred. This resulted in the formation of many grain boundaries, leading to low sinterability. These two factors, the impurity and grain boundary, have an enormous impact on the properties of Li1+XGaXTi2-X(PO4)3. The Li1.3Ga0.3 Ti1.7(PO4)3 pellet sintered at 900 °C was denser than those sintered at other conditions, showing the highest total ion conductivity of 7.66 × 10-5 S/cm at room temperature. The total activation energy of Li-ion transport for the Li1.3Ga0.3Ti1.7(PO4)3 solidstate electrolyte was estimated to be as low as 0.36 eV. Although the Li1+XGaXTi2-X(PO4)3 sintered at 1,000 °C had a relatively high apparent density, it had less total ionic conductivity due to an increase in the grain-boundary resistance with coarse grains.
        4,000원
        2.
        2018.04 구독 인증기관·개인회원 무료
        A colony of Solenopsis invicta was first intercepted on Gamman pier, Pusan port in Korea at September, 2017 by Animal and Plant Quarantine Agency. The mitochondrial DNA (mt-DNA) of workers was analyzed and compared with vary libraries of mt-DNA haplotypes to elucidate the origin of the introduced colony with the trade pattern of the Gamman pier. The mt-DNA fragment of 768 bp, which is part of the Cytochrome oxidae I gene, was amplified and sequenced. The results showed that the mt-DNA was in the clade of haplotype 5, which is endemic in southern USA, China, Taiwan, and Australia. More than 60% of containers are imported from China into Gamman pier, it may be possible to assume that the colony was inadvertently invaded through containers from China.
        3.
        2018.04 구독 인증기관·개인회원 무료
        Recently a colony of Solenopsis invicta, the red imported fire ant (RIFA), was intercepted on Gamman pier, Pusan port in Korea by Animal and Plant Quarantine Agency. It has been generally known that RIFA has two social forms as monogyne and polygyne, which showing the behavioral differences between the two forms and dictated by a pheromone binding protein, Gp-9. The social forms of the RIFA colony was revealed as polygyne form, when the GP-9 gene was analyzed by three allelic discrimination assays including Real-Time PCR (RT-PCR), rh-Amp SNP Genotyping, and peptide nucleic acid probe-based RT-PCR in this study.
        4.
        2006.04 구독 인증기관·개인회원 무료
        Thermal management technology is a critical element in all new chip generations, caused by a power multiplication combined with a size reduction. A heat sink, mounted on a base plate, requires the use of special materials possessing both high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) that matches semiconductor materials as well as certain packaging ceramics. In this study, nano tungsten coated copper powder has been developed with a wide range of compositions, 90W-10Cu to 10W-90Cu. Powder technologies were used to make samples to evaluate density, TC, and CTE. Measured TC lies among theoretical values predicted by several existing models.
        5.
        2006.04 구독 인증기관·개인회원 무료
        Nano-structured tungsten carbide compacts with cobalt matrices (WC-Co) offer new opportunities for achieving superior hardness and toughness combinations. A unified modeling and simulation tool has been developed to produce maps of sintering pathways from nanocrystalline WC powder to sintered nano-structured WC-Co compacts. This tool includes (1) die compaction, (2) grain growth, (3) densification, (4) sensitivity analysis, and (5) optimization. All material parameters were obtained by curve fitting based on results with two WC-Co powders. Critical processing parameters are determined based on sensitivity analysis and are optimized to minimize grain size with high density.
        6.
        2006.04 구독 인증기관·개인회원 무료
        Powder injection molding (PIM) is a suitable technology for the fabrication of complex shape titanium and its alloys, and has a great potential in many applications. This paper dealt with the injection molding of hydride dehydrogenization (HDH) titanium powder, spheroidized HDH titanium powder and gas atomized titanium powder. Rheological and thermalgravimetric behaviors were compared between the feedstocks of the three powders, and a tentative application of Ti PIM to eye frame temple and bridge was briefed.
        7.
        2006.04 구독 인증기관·개인회원 무료
        The master sintering curve (MSC) is derived from densification data over a range of heating rates and temperatures. To improve the accuracy, several modifications were proposed: multi-phase MSC for solid state sintering with phase changes, MSC for liquid phase sintering, and MSC with consideration of grain growth. The developed MSC models were applied to several material systems such as molybdenum, stainless steels, and tungsten heavy alloys (WHA), in order to evaluate the effect of compaction pressure, phase change, grain growth, and composition on densification, to classify regions having different sintering mechanism, and to help engineer design, optimize, and monitor sintering cycles.
        8.
        2006.04 구독 인증기관·개인회원 무료
        In recent years, micro powder injection molding is being explored as an economical fabrication method for microcomponents in microsystems technology (MST). Technical and economic comparison was performed for processes. Molding experiment and simulation during the filling process were performed to evaluate several different geometries and processing conditions. The influence of material parameters and process conditions on mold filling were examined as a function of features size using microchannels as an example. It was found that the heat conductivity and viscosity of feedstock, geometry and mold temperature were the most critical parameters for complete filling of micro features.
        9.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        On the analysis of triacylglycerol (TG) from the kernels of Acanthopanax sessiliflorus by reversed phase-HPLC, it was separated into three main fractions of PN 44, 46 and 48, according to partition number (PN). On the contrary, it could be clearly classified into seven fractions of SMM, MMM, SMD, MMD, SDD, MDD and MDT by silver ion-HPLC by the number of double bond in the acyl chains of TG species. But resolution of so-called critical pairs of TG molecular species such as molecular pairs of PeLL [C18:1Ω12/(C18:2Ω6)2] and OLL [C18:1Ω9/(C18:2Ω6)2] and OOL [(C18:1Ω9)2/C18:2Ω6], and PePeL [(C18:2Ω12)2/C18:1Ω6] was not achieved (Pe; petroselinic acid, L; linoleic acid, O; oleic acid). On the other hand, TG extracted from Aralia continentalis kernels were also fractionated into seven groups of SSM, SMM, MMM, SMD, MMD, SDD and MDD (S; saturated acid, M; monoenoic acid, D; dienoic acid) by silver ion-HPLC, although it's were classified into three groups of PN 44, 46 and 48 by reversed phase-HPLC. The fractions of SMM, MMM, MMD and MDD were divided into two subfractions, respectively; the fractions of SMM, MMM, MMD and MDD were resolved into the subfraction of PPe/Pe and POO (critical pairs from each other), that of Pe/Pe/Pe and OOO, that of Pe/Pe/L and OOL, and that of Pe/L/L and OLL.
        4,000원
        10.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fatty acid compositions of the seed oils of P. schinseng, A. continentalis and A. sessiliflorus, were analyzed by gas chromatography (GC) equipped with a capillary column. A large unusual peak was observed just before the peak corresponding to oleic acid (cis-9-C18:1). This unknown fatty acid was isolated by silver ion chromatography and then derivatized into the picolinyl ester. The mass spectrum of the picolinyl ester showed molecular ion at m/z=373 with other diagnostic ions such as m/z=178, 218, 232, 246, 274, 288, 302 and 344. Characteristic absorption peaks at 720 cm-1, 1640 cm-1 and 3010 cm-1 in IR spectrum indicated the presence of cis-configurational double bond in the molecule. The 1H-NMR spectrum of this acid gave two quintets centered at δ1.638 (2H, C-3) and δ1.377 (2H, C-4), and two multiplets centered at δ2.022~2.047 (2H, C-5) and δ2.000~2.022 (2H, C-8), and multiplet signals of olefinic protons centered at δ5.3015~5.3426 (C-6, J=9.5 Hz) and δ 5.3465~5.3877 (C-7, J=9.5 Hz). The 13C-NMR spectrum showed 18 carbon resonance signals including an overlapped signal at δ29.7002 for C-12 and δ29.6520 for C-13 (or they can be reversed), and other highly resolved signals at δ33.950, δ24.558, δ26.773 and δ27.205 due to C-2, C-3, C-5 and C-8 of a δ6-octadecenoic acid, respectively. From analysis results this unknown fatty acid could be identified as cis-6-octadecenoic acid. The seed oils of P. schinseng and A. sessiliflorus contained petroselinic acid (59.7%, 56.0%), oleic acid (18.3%, 6.1%) and linoleic acid (16.2%, 30.4%) with small amount of palmitic acid (3.0%, 3.1%) while the seed oil of A. continentalis comprised mainly oleic acid (30.2%), petroselinic acid (29.0%), linoleic acid (24.1%) and palmitic acid (13.1%).
        4,000원
        12.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A mixture of methyl ester derivatives of fatty acids from the oils of pine nuts was well resolved to five fractions differing by degree of unsaturation by silver ion solid-phase extraction column chromatography (Ag+-SEC). Polyunsaturated fatty acid with non-methylene interrupted conjugated double bond (NMiDB) radical held more strongly to silver ions in the column than methylene interrupted conjugated double bond (MiDB) one when they had the same number of double bonds. Although both the picolinyl ester and DMOX derivative provided clear mass ion species powerful enough to elucidate the structure of the polyunsaturated fatty acid (PUFA) with NMiDB and/or methylene interrupted conjugated double bond (MiDB) radical in the oils, the picolinyl ester of PUFA with NMiDB radical did not provide a cluster of mass ions neighboring diagnostic mass ions induced by the double bond in the proximal to the carboxyl group. However, the DMOX derivative of PUFA with NMiDB group as well as MiDB showed abundant mass ion species differing by gaps of 12 amu, which made it possible with greater ease to locate the double bonds in the molecule. The oil contained C18:2Ω6 (46.2 %) and C18:1Ω9 (25.4 %) as main components, and considerable amounts of PUFAs with NMiDB radical such as δ5. 9. 12-C18:3 (16.0 %), δ5. 9-C18:2 (2.3 %) and δ5. 11. 14-C20:3 (0.8 %).
        6,000원
        17.
        2019.07 KCI 등재 서비스 종료(열람 제한)
        Purpose – In this study, previous CSR researches was reviewed to help understand the CSR effects, and offer suggestions for future research directions. Research design, data, and methodology – To achieve the purpose of this study, previous CSR effects related researches were reviewed based on stakeholder perspectives. Results - After reviewing, some limitations were found. First, most of the CSR related studies in the management area have focused on CSR effects on individual stakeholders such as the shareholder, the employee, and the consumer. Second, it was difficult to find studies on the management aspect of CSR from both an effective and efficient perspective. Conclusions - To overcome these limitations of previous studies, several studies need to be conducted in the future. First, CSR research must be expanded into B-to-B businesses. Few studies try to figure out the effect of CSR on B-to-B businesses but only suggest the effect of CSR on B-to-B business conceptually. Therefore, empirical study needs to be conducted about CSR to show business performance in the B-to-B market. Second, the process of CSR must be developed on how to improve CSRs’ effectiveness and efficiency. Finally, a relationship between a company and individual stakeholders needs to be revised using stakeholders’ multiple identities.
        18.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        식물의 이차 대사산물은 다양한 생물활성을 가지며 자외선은 이차 대사산물의 생성에 영향을 미치는 것으로 알려져 있다. 뽕나무는 다양한 종류의 유용 성분을 함유하여 활용가치가 높은 식물 중의 하나이다. 본 연구에서는, UV 조사에 따른 뽕나무 잎의 이차 대사산물의 변화를 조사하기 위하여, 뽕나무 잎을 LC-MS를 이용하여 무표적 분석법으로 분석하였으며, 무표적 분석으로 얻은 scan data를 bioinformatics 프로그램인 R의 XCMS package를 이용하여 profiling 한 결과, 적어도 35종 이상의 화합물에서 UV-C 조사에 따른 양적인 변화가 발견되었다. 이들 중 14종의 화합물은 분리 및 NMR spectrum 비교 또는 표적 분석을 통하여 종류를 확인하였으며, 종류가 확인된 성분에 대해 정량분석을 수행한 결과, morin(464배), oxyresveratrol(256배), 2,3-trans-dihydromorin(170배), 2",4",2,4-tetrahydroxychalcone(120배), catechin(84배), 4"-prenyloxyresveratrol(43배), moracin M(35배) 등의 함량이 현저하게 증가한 것으로 나타났다. 또한 UV-C를 조사한 뽕나무 잎은 대조구에 비하여 항산화 활성이 2.1-2.4배, tyrosinase 억제 활성이 2.3배 증가한 것으로 조사되었다. 이러한 조사 결과는 자외선의 조사가 뽕나무 잎의 기능성을 향상시켜 기능성 식품, 약용 또는 화장품 소재로서의 활용 가치를 향상시키는 유용한 수단이 될 수 있음을 보인다.
        19.
        2008.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        최근 건강에 대한 관심이 높아지면서 과일 가공제품의 소비가 급증하고 있다. 포도는 페놀화합물의 주요 급원의 하나로 포도주스는 항산화, 항염증, 항혈소판 작용 등의 기능을 가지는 다수의 플라보노이드를 포함하고 있다. 일반적으로 캠벨 포도는 농가에서 주스나 와인으로 가장 널리 가공되고 있으나 다양한 포도 품종을 이용하여 브렌딩한 포도주스에 대한 연구는 거의 전무한 실정이다. 본 연구에서는 캠벨과 타품종 포도주스를 종류 및 비율을 달리하여 브렌딩 한