검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 57

        1.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The inclusion of conductive carbon materials into lithium-ion batteries (LIBs) is essential for constructing an electrical network of electrodes. Considering the demand for cells in electric vehicles (e.g., higher energy density and lower cell cost), the replacement of the currently used carbon black with carbon nanotubes (CNTs) seems inevitable. This review discusses how CNTs can contribute to the development of advanced LIBs for EVs. First, the reason for choosing CNTs as a conducting agent for the cathode is discussed in terms of energy density. Second, the reinforcing effect of CNTs on the anode is described with respect to the choice of silicon as the active material. Third, the development of water-based cathode fabrication as well as dry electrode fabrication with aid of CNTs is discussed. Fourth, three technical hurdles, that is, the price, dispersion issue, and entrapped metal impurities, for widespread use of CNTs in LIBs are discussed.
        4,000원
        2.
        2022.10 구독 인증기관·개인회원 무료
        In 2018, media reports raised issues related to radon released from building materials used as finishing materials in apartment houses. Accordingly, related ministries recommended not to use materials with a radiation index value exceeding 1. In order to calculate the radioactivity index, not only 226Ra producing radon (222Rn) but also 232Th and 40K radioactivity concentrations are required. To determine the concentration of the radionuclide, 40K is measured by a single gamma ray of 1,460.8 keV. And the 228Ac used to measure 232Th mainly utilizes gamma rays of 911.2 keV. However, 228Ac does not appear as a single peak unlike 40K, and appears as multiple peaks at various energies. Among them, gamma rays are emitted at a intensity of 0.83% at 1,459.2 keV, which is likely to interfere with 40K. Therefore, what is actually measured at 1,460.8 keV is theoretically a compound peak of 40K and 228Ac. Because the probability of emission at 1,459.2 keV (0.83%) is low, a low concentration of 232Th will result in little 40K radioactivity error. However, samples containing a high concentration of 232Th overestimate the 40K radioactive concentration, so correction is required. In this study, the IAEA standard substance (IAEA-RGTh-1) ontaining 232Th of actual high concentration was analyzed, and the results of the analysis without correction of 40K were compared and verified. As the 40K correction method, the 911.2 keV gamma-ray of 228Ac was used as the reference peak to separate the peak of 228Ac (1,459.2 keV) from the 40K (1,460.8 keV) mixed peaks. And, the coefficient value obtained by subtracting the peak of 228Ac (1,459.2 keV) from the 40K (1,460.8 keV) mixed peak was set to a pure peak of 40K and the radioactivity concentration was calculated therefrom. As a result of calculating the IAEA-RGTh-1 reference material without correction, it was confirmed that the 40K value was overestimated by about 38 times. If a measurement beyond the MDA of 40K is generated by 228Ac radioactivity because the 40K correction constant is not applied, there is an error in determining that there is 40K radioactivity. However, even if 40K radioactivity is overestimated due to the high concentration of 232Th, the degree to which this effect contributes to the radioactivity index is very small. However, as an analyst, 40K radioactivity correction should be made for more accurate analysis.
        4.
        2022.05 구독 인증기관·개인회원 무료
        RADTRAN is a code that assesses the radiation risk of radioactive material transportation. RADTRAN assumes that the package is a point source or a line source regardless of package type and corrects the external dose rate using a shape factor which depends on the critical dimension of the package. However, the external dose rate calculated using a shape factor may be different from the actual external dose rate. Therefore, it is necessary to analyze the effect of the shape factor on the external dose rate. In this study, the effect of the shape factor on the external dose rate in RADTRAN was analyzed by comparison with MCNP. This study analyzed change in external dose rate depending on the distance from the package and the critical dimension. The distance from the package was in the range of 1–800 m. The shape of the package was assumed to be cylindrical with a radius of 1 m, and the critical dimensions of the package were assumed to be 2, 4, and 8 m. Attenuation and build-up in the air were not considered to consider only the effect on the shape factor. When simulating the exposure situation using MCNP, the package was assumed to be a volume source, and flux by distance from the package was calculated using F5 tally. The dose rate at 1 m from the package was normalized to 2 mSv·hr−1. As a result of the analysis, the external dose rates of the package were higher in RADTRAN than in MCNP. For the critical dimension of 2, 4, and 8 m, when the distance from package is 1–10 m, the RADTRAN was 1.83, 4.08, and 5.27 times higher on average than MCNP, respectively. And when the distance from the package was 10–100 m and 100–800 m, RADTRAN was 1.10, 2.02, 3.01 times and 1.04, 1.92, 2.43 times higher than MCNP, respectively. It was found that the larger the distance from the package is and the smaller the critical dimension of the package is, the less conservatively RADTRAN assessed. It is because the shape of the package gets closer to the point source as the distance from the package increases, and the shape factor decreases as the critical dimension of the package decreases. The result of this study can be used as the basis for radiation risk assessment when transporting radioactive materials.
        5.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        공상과학소설(Science-Fiction; 이후 Sci-Fi로 표기)은 미래 세계에 대한 인간의 판타지를 표현하는 장르다. 이는 TV 쇼, 영화, 게임 분야에서 항상 뜨거운 주제였다. Sci-Fi 영화와 Sci-Fi 게임은 대부분 상위권에 오르고 있다. 하지만, 학계에서는 주로 Sci-Fi 영화에서 대한 논의에 더 집중하는 경향이 있다. 예를 들어, <Research on Color Modes of Well-known Contemporary Films(2020)>에 따르면, 최근 몇 년 동안 할리우드 Sci-Fi 영화의 주류 색상은 빨간색과 파란색에서 주황색, 노란색, 파란색, 녹색으로 바뀌었다고 분석하고 있다. 또한, Sci-Fi 영화와 관련된 질적 연구와 연구의 많은 성과가 있었다. 그러나 Sci-Fi 게임의 색조 경향에 대한 연구와 연구 는 매우 부족한 상황이다. 이에 본 논문은 Adams Roberts의 Sci-Fi 소설의 7가지 요소를 사용 한다. 이러한 7 가지 요소에 대한 Metacritic 점수가 사례 선택의 표준으로 사용되었다. 본 연구의 분석 대상으로는<HALO 3>, <Death Stranding>, <Cyberpunk 2077> 등 우수 PC게임 3종이 선정하였다. 또한, 데이터 분석은 NCS 색상 시스템을 기반으로 수행되어 Sci-Fi 게임의 색조 유사성에 대해 논의한다. 마지막으로, 우수한 게임의 색상 적 용에 대한 주요 성향을 결론짓고 요약함으로써, 본 연구는 Sci-Fi 게임의 색상 생산에 대한 몇 가지 이론적 참 조와 기초 데이터를 제공하고자 한다.
        4,000원
        9.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to investigate the effect of an aluminum chromium nitride (AlCrN) coating on tool wear and hole quality in the conventional drilling process of carbon fiber-reinforced plastic (CFRP) composites, titanium alloy (Ti), and CFRP–Ti stack workpieces popular in the aerospace industry. The advanced arc plasma acceleration (APA) method of physical vapor deposition (PVD) was used for all AlCrN coatings. The drilling experiments were conducted with uncoated drills as well as AlCrN-coated drills. When drilling CFRP only, the AlCrN coating was removed at the drill cutting edges and the margin area, which suggests the carbon fibers abraded the coatings. When drilling Ti only, the AlCrN-coated drill mitigated the Ti adhesion formation, which resulted in less tool wear. In addition, hole quality for both CFRP and Ti was improved when the coating was used versus the uncoated tool. The machinability of CFRP–Ti stacks in the drilling process was improved by utilizing the advanced AlCrN coating on the WC tool in terms of drilling forces and hole quality parameters such as average hole size, average hole roundness, hole surface roughness, and Ti exit burr height.
        4,200원
        12.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Seaports are under high-speed developing and booming with the extend of the facilities and equipment to support the port activities and industry’s needs. It may bring environment destruction due to the change of the environmental conditions, likes forests, soils, water, and air. Therefore, this paper aimed to analyze the negative environmental impact due to seaport activities in Malaysia. The priority dominant factors are determined through analytic hierarchy process (AHP). Malaysia Port is selected as case study and 20 respondents are selected from virous department based on their expertise. Pari-wise comparison survey is used to collect data. The results shown that the negative environmental impact’s main elements are water (0.451), noise (0.262), organism (0.181), and air (0.106). Meanwhile, the toxicity is the prominent negative environmental impact’s sub-element of port activities, which scored 0.241, followed by interfering communication (0.142), and smell (0.134). The CR values are less than 0.1 and are considered acceptable. Hence, the outcome of the paper stimulated public awareness toward environmental protection. The development and expansion of seaports must consider environment conservation and preservation, and it cannot bring irreparable sequelae to the earth.
        4,000원
        14.
        2020.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fish influx and behavioral properties at a set-net off Goseong, South Korea were investigated using an imaging sonar. As a result, the average influx of fish was 33.9% at day time and 66.1% at night time, respectively, which indicated that a majority of fish entered into a playground in the set-net at night. The fish behavioral properties such as target (fish) length, range, orientation and major-axis angle were examined and compared among survey dates (4, 5, and 6 June 2019) using the statistical analysis tool (analysis of variance, ANOVA). The behavioral properties presented differently sometime of survey dates. This is preparatory study to support fish behavior properties in a set-net. It is expected that more elaborated behavioral information of fishes in the set-net is beneficial for designing and deploying a set-net fishing gear as well as general fish behavior research in the future.
        4,000원
        16.
        2019.04 구독 인증기관·개인회원 무료
        Methyl bromide (MB) has been still routinely used in quarantine fumigation on imported citrus, although there had been issuing chronic inhalation toxicity to fumigators and related workers as well as phytotoxic damages after fumigation. Ethyl formate (EF), is the only option to replace MB in terms of its safety for consumers (food additive and naturally occurred) and worker with higher threshold level limit (TLV = 100 ppm). Its application technology also provide cost effectiveness, good commercial practice in terms of application time (< 10 min) for 40 ft container. The replacement of MB with EF is recommended not to fumigate with hazardous and phasing-out MB on imported oranges.
        17.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the study was to investigate the immediate effects of negative pressure soft tissue therapy on muscle tone, muscle stiffness and balance in patients with stroke. In total, 20 patients with stroke and assigned to the negative pressure soft tissue therapy group (NPST, n=10) or, placebo-negative pressure soft tissue therapy group(Placebo-NPST, n=10). Both groups underwent NPST or placebo-NPST once a day during the experimental period. MyotonPRO was used to assess the parameters for muscle tone and stiffness. Biorescue was used to assess the parameters for balance. Each group showed improvements in muscle tone, muscle stiffness, and balance ability (p<.05). Especially, Muscle tone, muscle stiffness, and anterior length in the limit of stability were the significant improvement on NPST group (p<.05). The results of the study suggest that the NPST is effective in improving muscle tone, muscle stiffness, and balance ability in patients with stroke.
        4,000원
        18.
        2017.10 구독 인증기관·개인회원 무료
        The antioxidant and antitumor properties of natural products, often recognized in traditional medicine systems, represent therapeutic modalities to reduce or prevent uncontrolled oxidation processes which in turn potentially ameliorate or tumor based symptoms of chronic diseases. We have studied the antioxidant and antitumor effects of Amanita muscaria (A. muscaria) in vitro and examined whether the A. muscaria has synergistic effects on antioxidant and antitumor properties. Although A. muscaria induced a dose-dependent increase in antioxidant activity, the latter has a consistently higher antioxidant effect. In mouse monocytes, the lipopolysaccharide- (LPS-) induced tumor necrosis- (TNF-) synthesis was significantly inhibited by A. muscaria in a dose dependent manner and synergistic effects were clearly demonstrated with the A. muscaria on TNF- inhibition. A. muscaria effect was also evident on inhibition of nuclear factor-kappa B activity, cyclooxygenase-II activity, and lipid peroxidation in mouse monocytes. This presented results may be a starting point for a comprehensive characterization of biological effects of A. muscaria.
        19.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The stability of the steady Rossby-Haurwitz wave (R-H wave) in the nondivergent barotropic model (NBM) on the sphere was investigated with the normal mode method. The linearized NBM equation with respect to the R-H wave was formulated into the eigenvalue-eigenvector problem consisting of the huge sparse matrix by expanding the variables with the spherical harmonic functions. It was shown that the definite threshold R-H wave amplitude for instability could be obtained by the normal mode method. It was revealed that some unstable modes were stationary, which tend to amplify without the time change of the spatial structure. The maximum growth rate of the most unstable mode turned out to be in almost linear proportion to the R-H wave amplitude. As a whole, the growth rate of the unstable mode was found to increase with the zonal- and total-wavenumber. The most unstable mode turned out to consist of more-than-one zonal wavenumber, and in some cases, the mode exhibited a discontinuity over the local domain of weak or vanishing flow. The normal mode method developed here could be readily extended to the basic state comprised of multiple zonalwavenumber components as far as the same total wavenumber is given.
        4,000원
        1 2 3