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        검색결과 13

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Photocatalytically splitting water into hydrogen upon semiconductors has tremendous potential for alleviating environmental and energy crisis issues. There is increasing attention on improving solar light utilization and engineering photogenerated charge transfer of TiO2 photocatalyst because it has advantages of low cost, non-toxicity, and high chemical stability. Herein, oxygen vacancies and cocatalysts (Cu and MoS2) were simultaneously introduced into TiO2 nanoparticles from protonic titanate by a one-pot solvothermal method. The composition and structure characterization confirmed that the pristine TiO2 nanoparticle was rich in oxygen vacancies. The photocatalytic performances of the composites were evaluated by solar-tohydrogen evolution test. The results revealed that both Cu-TiO2 and MoS2- TiO2 could improve the photocatalytic hydrogen evolution ability. Among them, 0.8% Cu-TiO2 showed the best hydrogen evolution rate of 7245.01 μmol·g−1·h−1, which was 3.57 and 1.34 times of 1.25% MoS2- TiO2 (2726.22 μmol·g−1·h−1) and pristine TiO2 material (2028.46 μmol·g−1·h−1), respectively. These two kinds of composites also had good stability for hydrogen evolution. Combined with the results of photocurrent density and electrochemical impedance spectra, the incorporation of oxygen vacancies and cocatalysts (Cu and MoS2) could not only enhance the light-harvesting of TiO2 but also improve the separation and transfer capabilities of light-induced charge carriers, thus promoting water splitting to hydrogen.
        4,600원
        3.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Curing agents are critical components of aqueous epoxy resin systems. Unfortunately, its uses and applications are restricted because of its low emulsifying yields. Epoxy resins are frequently used in electrical devices, castings, packaging, adhesive, corrosion resistance, and dip coating. In the presence of curing agents, epoxy resins become rigid and infusible. Eco-friendliness and mechanical functionality have emerged as vulcanization properties. Curing agents are used for surface modification, thermodynamic properties, functional approaches to therapeutic procedures, and recent advances in a variety of fields such as commercial and industrial levels. The curing agent has superior construction and mechanical properties when compared to the commercial one, which suggests that it has the potential for use as the architectural and industrial coatings. The thermal stability of cured products is good due to the presence of the imide group and the hydrogenated phenanthrene ring structure. Over the course of the projection period, it is anticipated that the global market for curing agents will continue to expand at a steady rate. The growth of the market is mainly driven by its expanding range in future applications such as adhesives, composites, construction, electrical, electronics, and wind energy. This review focused on the most recent advancements in curing techniques, emphasizing their thermal and mechanical properties. The review also presents a critical discussion of key aspects and bottleneck or research gap of the application of curing agents in the industrial areas.
        5,200원
        4.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Photocatalytic CO2 reduction is a promising approach for reducing CO2 emissions and achieving the goal of carbon neutrality. In this work, selectively coupling Cu(OH)2 and CuO with amine-modified brookite TiO2 ( NH2–B–TiO2) has been achieved by a simple precipitation method. The results show that CuO is better than Cu(OH)2 as a co-catalyst to enhance the CO2 photoreduction capability of NH2– B–TiO2. The highest rates of CO2 conversion to CH4 and CO of NH2– B–TiO2–CuO composite reach 6.05 and 3.25 μmol h− 1 g− 1, respectively, which is higher than 8 times the yield of CH4 of NH2– B–TiO2. It is proposed that the NH2– B–TiO2–CuO composite offers an effective charge transfer through the formation of a p–n junction between NH2– B–TiO2 and CuO interfaces, while in the NH2– B–TiO2–Cu(OH)2 composite, the Cu(OH)2 dominantly serves as an electron sink to capture photo-induced electrons, promoting photo-induced carrier separation. This work provides an ingenious synthetic method for selectively anchoring Cu(OH)2 and CuO on semiconductors with different charge transfer routes for an efficient CO2 photoreduction.
        4,300원
        5.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Modified pitch A (MPA) and modified pitch B (MPB) were prepared by oxidative polymerization and thermal polycondensation reaction with refined pitch as the raw material, respectively. The toluene soluble components (TS-1 and TS-2) were obtained by solvent extraction from MPA and MPB, separately. The Flynn-Wall-Ozawa method and Kissinger-Akahira- Sunose method were used to calculate the pyrolysis activation energy of TS. The Satava- Sestak method was used to investigate the pyrolysis kinetic parameters of TS. Moreover, the optical microstructure of the thermal conversion products (TS-1-P and TS-2-P) by calcination shows that TS-1-P has more contents of mosaic structure and lower contents of fine fiber structure than TS-2-P. The research result obtained by a combination of X-ray diffraction and the curve-fitting method revealed that the ratios of ordered carbon crystallite (Ig) in TS-1-P and TS-2-P were 0.3793 and 0.4417, respectively. The distributions of carbon crystallite on TS-1-P and TS-2-P were calculated by Raman spectrum and curve-fitting analysis. They show that the thermal conversion product of TS-2 has a better graphite crystallite structure than TS-1.
        4,000원
        6.
        2014.07 구독 인증기관·개인회원 무료
        This study used the methods of decision tree analysis, association rule analysis, and Kano’s model to explore the behavior patterns of mainland China tourists staying at the international tourist hotels in Taiwan. To this end, the data of their demographics, travel variables, overall satisfaction with the lodging experience, different service quality perceptions, and loyalty intentions were included. The decision tree analysis showed that a tourist’s overall satisfaction with the lodging experience, satisfaction with the quality of core intangible services, and certain demographic characteristics are three important determinants of tourist loyalty towards the hotels. In terms of the effect of demographics, the customers’ monthly income and length of stay at the hotel are two main determinants in this study. In addition, if the customer perceptions of different parts of hotel service quality are taken into account, among the five hotel service quality domains, core intangible services from the receptionist, housekeeping personnel, and food & beverage personnel are found to be important influences on hotel customer loyalty intention. In other words, high quality intangible services are important for luxury hotels to demonstrate their unique ability to help customers experience the service quality that creates loyalty intentions. With regard to the association rule analysis, the results showed that core intangible service aspects from the receptionist, housekeeping personnel, and food & beverage personnel are strongly associated with customer loyalty intentions, as are the tangible aspects of the reception and hotel room facilities. The former indicated that reception in the hotel lobby could be considered one of the most important servicescapes because of its impact in forming many of the first impressions of hotel guests, while the latter is treated as core offerings in hotels that would be encountered by most hotel customers. If the tourists are mainly from package tours, the intangible services and tangible facilities of these areas are the important areas to create customer satisfaction. However, if the tourists are mainly independent tourists because they have more time and free choice to stay at the hotel longer than the package tour tourists, the intangible services and tangible facilities of the entertainment or business centers would be even more important to these tourists than to the package tour tourists. With regard to Kano’s model analysis, the results showed that, based on mainland China tourists’ perceptions, most of the service elements fit into the category of one-dimensional quality attributes. This means that these service elements are positively and linearly related to customer satisfaction, and the greater fulfillment of the attribute results in a greater degree of satisfaction. This also means that hotels should make more effort to innovate their intangible services and tangible facilities to create business advantages in the market.
        8.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        An efficient somatic embryogenesis and plant regeneration protocol was developed for Schisandra chinensis Baill, using embryogenic cell suspensions and optimized media conditions. Friable embryogenic callus was induced from cotyledonary leaf and hypocotyl explants of 7 days old seedlings on MS agar medium supplemented with 1.0 to 4.0 mg l-1 of 2,4-dichlorophenoxyacetic acid (2,4-D). Fast growing and well dispersed embryogenic cell suspensions were developed within two months when embryogenic calli were transferred to MS liquid medium containing 1.0 mg l-1 2,4-D. One third strength of MS medium was the best for both overall growth and development of somatic embryos in liquid culture. Over 3400 viable somatic embryos were produced from each 150 ml flask with an initial cell density of 30 mg in 30 ml medium. Germinated somatic embryos developed in liquid medium converted into plantlets after transferred to half-strength MS semi-solid medium. Approximately 90% of the converted plantlets were successfully transplanted to soil and grew into fertile plants.
        9.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        Field performance and morphological characterization was conducted on seven transgenic lines of Codonopsis lanceolata expressing γ-TMT gene. The shoots were obtained from leaf explants after co-cultivation with Agrobacterium tume-faciens strain LBA 4404 harboring a binary vector pYBI 121 that carried genes encoding γ-Tocopherol methyltransferase gene (γ-TMT) and a neomycin phosphotransferase II gene (npt II) for kanamycin resistance. The transgenic plants were transferred to a green house for acclimation. Integration of T-DNA into the T0 and T1 generation of transgenic Codonopsis lanceolata genome was confirmed by the polymerase chain reaction and southern blot analysis. The progenies of transgenic plants showed phenotypic differences within the different lines and with relative to control plants. When grown in field, the transgenic plants in general exhibited increased fertility, significant improvement in the shoot weight, root weight, shoot height and rachis length with relation to the control plants. However, all seven independently derived transgenic lines produced normal flower with respect to its shape, size, color and seeds number at its maturity. Indicating that the addition of a selectable marker gene in the plant genome does not effect on seed germination and agronomic performance of transgenic Codonopsis lanceolata. T1 progenies of these plants were obtained and evaluated together with control plant in a field experiment. Overall, the agronomic performance of T1 progenies of transgenic Codonopsis lanceolata showed superior to that of the seed derived non-transgenic plant. In this study, we report on the morphological variation and agronomic performance of transgenic Codonopsis lanceolata developed by Agrobacterium transformation.
        11.
        2007.04 KCI 등재 서비스 종료(열람 제한)
        An efficient regeneration system was developed using leaf, petiole, and internode explants. Highly embryogenic callus was obtained following cultivation on MS basal nutrient supplemented with 2 mg/l 2,4-D. Globular, heart, torpedo and cotyledon shaped somatic embryo were produced from the surface of embryogenic callus. Direct shoot regeneration without intermediate callus formation has been achieved on MS medium supplemented NAA and BAP. The percentage of response varies with different concentration of auxin and cytokinin treated individually or in combination. The best shoot regeneration response (54.28%) and number of shoot per explant (12.67) were achieved on the medium supplemented with 0.1 mg/l NAA and 1 mg/l BAP. The regenerated shoot transformed into young plant when cultured into elongation and root induction medium. More than 90% of in vitro propagated plants could survive when transferred to the greenhouse for acclimation. This optimized regeneration system can be used for rapid shoot proliferation and genetic transformation.
        12.
        2005.04 KCI 등재 서비스 종료(열람 제한)
        Acifluorfen tolerance charateristics determined the involvement of absorption, translocation, and metabolism in acifluorfen tolerance. Less than 6% of the applied 14C-acifluorfen was absorbed. There were no differences in acifluorfen absorption between susceptible and tolerant somaclones. More 14C-acifluorfen was translocated in the susceptible than the tolerant somaclones. The susceptible somaclone did not metabolize acifluorfen while some somaclones (i.e.,EBN-3A) metabolized 14C-acifluorfen. Nomenclature: Acifluorfen, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid; eastern black night shade, Solanum ptycanthum Dun.,#3 SOLPT.