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        검색결과 17

        1.
        2023.07 구독 인증기관·개인회원 무료
        The attitude-behavior gap and intention-behavior gap has not been research extensively. The purpose of this study is to provide a review of moderating or mediating factors on the relationship between intention or attitude and behavior of sustainable tourism. Intention was defined as the degree of a human being’s resolve to perform a certain action. The construct ‘Intention” has been used widely in some theories like the Theory of Planned Behavior. Researchers usually include the intention construct into their research framework to explain the theoretical mechanism. Sustainable or ecological tourism education has been implemented for years and empirical evidence provides us that almost all tourists are alerted to the importance of sustainability. There is a great challenge that tourists’ behavior might not concur with their intention. Policymakers and marketers really want to know the real factors affecting the association between the intention and behavior of sustainable tourism. Tourists’ purchase intention is a rational process and is affected by safety. Tourist behavior is associated with price and service environment which is a mixture of rational and emotional considerations.
        2.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO2) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.
        4,600원
        3.
        2021.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Strontium lanthanum vanadate La1-xSrxVO3 (LSVO) is a promising anode material for electrochemical devices, especially for solid oxide fuel cells, thanks to its irregular electrical conductivity. However, the known synthesis methods are incapable of producing well-dispersed LSVO nanoparticles (NPs) with homogeneous size distribution, which partly impedes the applicability of the material. Thus, a new approach to synthesize LSVO NPs with such characteristics is of paramount importance. In the present work, we successfully prepare LSVO NPs with a high dispersion degree and homogeneous size distribution via a modified co-precipitation pathway, followed by hydrogen reduction at a temperature as low as 700 oC. The prepared LSVO NPs display uniform sizes in the range of 50 ~ 100 nm and do not contain any secondary phases, according to XRD analysis. The chemical mechanism of reactions that occur to form the LSVO is thoroughly highlighted. The work functions of NPs measured by the UPS analysis are in the 2.13 ~ 3.62 eV range, making the LSVO powders promising for use in thermionic devices. An explanation of the role of Sr substitution in work function values of LSVO is also proposed.
        4,000원
        4.
        2018.05 구독 인증기관·개인회원 무료
        A number of roller-compacted concrete pavements (RCCP) have been constructed without saw-cut joints in order to save construction cost. Then it will allow natural cracks to randomly occur at the early age after concrete placement. Crack spacing of unjointed RCCP is crucial to ensure an adequate crack width and load transfer across the cracks since large crack spacing will result in excessive crack width and reduce load transfer efficiency that may be cause faulting, excessive deflection, and further cracking in RCCP slab. Due to pavement thickness, climatic condition, and material properties, unjointed RCCP may have different natural crack spacing. In this study, an analytical approach to predict natural crack spacing of an unjointed RCCP was developed. An analytical method based on elastic theory to calculate axial restraint stress using a bilinear slab-subbase interfacial constraint assumption was conducted. Curling stress induced by temperature gradient through the depth of the slab was also considered. The analytical model incorporates the environmental effect, strength gain and modulus of elasticity, coefficient of thermal expansion, drying shrinkage, base type materials, and slab geometries. The predicted crack spacing results obtained from the predictive model were validated through field measured data. The results showed a good agreement compared with crack spacing measured in the field. Furthermore, the result from a sensitive analysis using proposed predictive model showed that crack spacing increased when thickness of RCCP increased. The predicted crack spacing results may be used as input parameters to estimate crack widths in unjointed RCCP under given climatic condition, and material properties. If estimated crack width is excessive and cannot maintain an adequate load transfer across the cracks, saw-cut joints with an appropriate spacing should be provided in order to minimize crack width, and to prevent future cracking of RCCP leading to better performance.
        5.
        2017.04 구독 인증기관·개인회원 무료
        The physicochemical and sensorial properties of fibrous tofu with the addition of different sized defatted soybean flour (DSF) were investigated. Coarse DSF (DSF-150; D50 = 279 μm), fine DSF (DSF-63; D50 = 105 μm), and super-fine DSF (DSF-JM; D50 = 5.0 μm) were prepared via conventional sifting followed by jet-milling with the milling pressure of 7 bars. Tofu was made with the 5% addition of coarse DSF (TDSF-63), fine DSF (TDSF-150), superfine DSF (TDSF-JM), and without DSF (TC). The yields of tofu were slightly decreased as coarse and fine DSF were incorporated while the yield of tofu with super-fine DSF was statistically identical with that of control tofu (p<0.05). Tofu with larger DSF (TDSF-63 and TDSF-150) showed less smoother texture and less pure in color, while tofu with superfine DSF (TDSF-JM) resulted in little changes in physical and organoleptic qualities, which were verified by quantitative descriptive analysis (QDA), texture profile analysis (TPA), and color measurements. Each fibrous tofu samples were prepared by mixing soymilk with 5% of DSF from sifting (150 μm, 63 μm sieve) and jet milling process which mentioned as TDSF-150 (DSF average particle size), TDSF-63 (D50 = 105 μm) and TDSF-JM (D50 = 5 μm), respectively. The fibrous tofus were compared to the normal tofu (TC). TDSF-JM has higher yielded (50.98%) among tofu samples. The moisture content of TC, TDSF-JM, TDSF-150 and TDF-63 were 75.81%, 75.47%, 69.89% and 69.80%, respectively. TDSF-JM and TC were having similar L-a-b index. Texture properties of TDSF-JM were similar with TC. On the other hand, TDSF-150 and TDSF-63 has statistically significant higher hardness value and lower point on springiness and cohesiveness compared with TC. Sensory evaluation with quantitative descriptive analysis (QDA) method shown that hardness, mouth feel and beany flavor intensity were decreased with the decreasing of particle size of DSF.
        6.
        2016.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present analyses of 1250 variable sources identi ed in a 20 square degree eld toward NGC 2784 by the KMTNet Supernova Program. We categorize the variable sources into three groups based on their B-band variability. The rst group consists of 31 high variability sources with their B- band RMS variability greater than 0.3 magnitudes. The second group of medium variability contains 265 sources with RMS variability between 0.05 and 0.3 magnitudes. The remaining 951 sources belong to the third group of low variability with an RMS variability smaller than 0.05 magnitudes. Of the entire 1250 sources, 4 clearly show periods of variability greater than 100 days, while the rest have periods shorter than 51 days or no reliable periods. The majority of the sources show either rather irregular variability or short periods faster than 2 days. Most of the sources with reliable period determination between 2 and 51 days belong to the low-variability group, although a few belong to the medium-variability group. All the variable sources with periods longer than 35 days appear to be very red with B􀀀V > 1.5 and V 􀀀I > 2.1 magnitudes. We classify candidates of 51 Cepheids, 17 semi-regular variables, 3 Mira types, 2 RV(B) Tauri stars, 26 eclipsing binary systems and 1 active galactic nucleus. The majority of long-term variables in our sample belong to either Mira or semi-regular types, indicating that long-term variability may be more prominent in post-main sequence phases of late-type stars. The depth of the eclipsing dips of the 26 candidates for eclipsing binaries is equivalent to 0.61 as the average relative size of the two stars in the binary system. Our results illustrate the power of the KMTNet Supernova Program for future studies of variable objects.
        4,800원
        7.
        2015.09 구독 인증기관 무료, 개인회원 유료
        Biofilms of oral microbes can cause various diseases in the oral cavity, such as dental caries, periodontitis and mucosal disease. Electrolyzed water generated by an electric current passed via water using a metal electrode has an antimicrobial effect on pathogenic bacteria which cause food poisoning. This study investigated the antimicrobial activity of electrolyzed waters using various metal electrodes on the floatage and biofilms of oral microbes. The electrolyzed water was generated by passing electric current using copper, silver and platinum electrodes. The electrolyzed water has a neutral pH. Streptococcus mutans, Porphyromonas gingivalis and Tannerella forsythia were cultured, and were used to form a biofilm using specific media. The floatage and biofilm of the microbes were then treated with the electrolyzed water. The electrolyzed water using platinum electrode (EWP) exhibited strong antimicrobial activity against the floatage and biofilm of the oral microbes. However, the electrolyzed water using copper and silver electrodes had no effect. The EWP disrupted the biofilm of oral microbes, except the S. mutans biofilm. Comparing the different electrolyzed waters that we created the platinum electrode generated water may be an ideal candidate for prevention of dental caries and periodontitis.
        4,000원
        8.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However, the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast dif-ferentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)- positive multinucleated cells induced by 10 nM 1α,25(OH)2 D3 in a dose‐dependent manner. A cell viability test revea-led no marked cellular damage by up to 100 mM of xylitol. Exposure of osteoblastic cells to xylitol decreased RANKL, but not OPG, mRNA expression in the presence of 10-8 M 1α,25(OH)2D3 in a dose‐dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the co- culture system, was found to be dramatically decreased with increasing xylitol concentrations. RANKL and OPG proteins were assayed by ELISA and the soluble RANKL (sRANKL) concentration was decreased with an increased xylitol con-centration. In contrast, OPG was unaltered by any xylitol con-centration in this assay. These results indicate that xylitol inhibits 1α,25(OH)2D3-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.
        4,000원
        10.
        2008.12 구독 인증기관 무료, 개인회원 유료
        Inositol 1,4,5-trisphosphate (IP₃) plays an important role in the release of Cα²+ from intracellular stores into the cytoplasm in a variety of cell types. IP₃ translocation dynamics have been studied in response to many types of cell signals. However, the dynamics of cytosolic IP₃ in salivary acinar cells are unclear. A green fluorescent protein (GFP)-tagged pleckstrin homology domain (PHD) was constructed and introduced into a phospholipase C δ1 (PLC δ1) transgenic mouse, and then the salivary acinar cells were isolated. GFP-PHD was heterogeneously localized at the plasma membrane and intracellular organelles in submandibular gland and parotid gland cells. Application of trypsin, a G protein-coupled receptor activator, to the two types of cells caused an increase in GFP fluorescence in the cell cytoplasm. The observed time course of trypsin-evoked IP₃movement in acinar cells was independent of cell polarity, and the fluorescent label showed an immediate increase throughout the cells. These results suggest that GFP-PHD in many tissues of transgenic mice, including non-cultured primary cells, can be used as a model for examination of IP₃intracellular dynamics.
        4,000원