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        검색결과 9

        1.
        2023.07 구독 인증기관·개인회원 무료
        This study examines the impact of influencer-audience and audience-audience interactions in Livestream e-commerce by extending halo of the influencer to the brand and snowballing the opinions that empower other watchers. It finds that halo effect generates from influencer physical attraction and bandwagon effect from audience live comments significantly influenced product preference and purchase intentions.
        2.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydrogen energy is a promising source of renewable and clean energy for various industries, such as chemical, automobile, and energy industries. Electrolysis of water is one of the basic methods for the production of hydrogen energy. However, the high overpotential of the oxygen evolution reaction (OER) in water electrolysis has hindered the effective production of hydrogen using this method. Thus, the development of high-efficiency non-precious metal-based electrocatalysts for OER is extremely significant. In this study, we adopted a one-step hydrothermal method to fabricate Ni-based catalysts with N/Sdual doped graphene oxide/carbon nanotube (GO/CNT) supports using thiourea ( CH4N2S) and urea as the S source and the N source. It was observed that the amount of thiourea utilized in the synthesis of the catalyst affected the morphology, composition, and the electrochemical properties of the catalyst. For a GO/CNT-to-thiourea mass ratio of 1:10, the catalyst exhibited the highest activity, where the OER overpotential was 320 mV at a current density of 10 mA/cm2. This was attributed to the high specific surface area, high conductivity, and fast electron transport channels of the N/S-dual doped GO/ CNT composite. Furthermore, sulfurization of the Ni particles to form nickel sulfide played a significant role in enhancing the catalytic performance.
        4,000원
        3.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Highly luminescent carbon quantum dots (CQDs) are developed as fluorescent probes for selective detection of the heavy-ion Fe3+, where the CQDs exhibit excellent nontoxicity, functionalizability, sensitivity, and selectivity. Biomass-based CQDs and nitrogen-doped CQDs (N-CQDs) are synthesized for the selective detection of Fe3+ by using H2O2 as an oxidant and polyetherimide (PEI) as a nitrogen precursor by a green hydrothermal synthesis method. The prepared CQDs and N-CQDs exhibit an elliptical morphology and with an average particle size of 7 and 4 nm, respectively, and emit blue photoluminescence at 445 and 468 nm under excitation at 367 and 343 nm, respectively. The CQDs and N-CQDs exhibit good water solubility because of the abundant hydroxyl and carboxyl/carbonyl groups and graphic/pyrrolic/pyridinic nitrogen on the surfaces, giving rise to a quantum yield of about 24.2% and 30.7%, respectively. Notably, the Matrimony vine-PEI-based CQDs exhibit excellent Fe3+ selectivity and sensitivity relative to the Matrimony vine-based CQDs due to complexation of the numerous phenolic hydroxyl groups and nitrogen-containing groups with Fe3+, leading to increased fluorescence quenching, which greatly improves the sensitivity of detection. The minimum detection limit was 2.22 μmol L− 1 with a complexation constant of 44.7.
        4,000원
        4.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen-doped carbon dots (N-CDs), derived from the biomass (anthocyanin), are the novel additive to the nanocarbon materials, which is expected to bring a wide spectrum of novel applications. Moreover, metallic oxides are emerging for their unique potential for electrocatalysis. Herein, we report the synthesis of N-CDs for the selective detection of Fe3+ with a limit of detection of 2.57 μM in the range of 5–60 μM using ethylenediamine and H2O2 by a hydrothermal method. The obtained N-CDs displayed a spherical morphology with a particle size range of 2–7 nm and emitted blue luminescence at 394 nm under excitation at 319 nm. Meanwhile, we have demonstrated the fabrication of cost-efficient electrocatalysts for oxygen evolution reaction (OER) in an alkaline medium, employing N-CDs. Owing to the successful incorporation of N-CDs into NiO nanospheres, the resulting N-CDs/NiO with large surface areas, fast charge transfer, and increased conductivity vastly improved the catalytic activity. Remarkably, the optimal of N-CDs/NiO composite requires the overpotential of only 380 mV at a current density of 10 mA cm− 2 and a relatively low Tafel slope of 57.96 mV dec− 1 compared with pure NiO. These results open up a facile route for the application of N-CDs and offer prospects for CD-metal hybrids as high OER catalysts in electrochemical energy devices.
        4,300원
        5.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hierarchical porous carbons (HPCs) have been successfully prepared by a facile carbonization and subsequent CO2 activation process using corncob as a natural carbon precursor and Mg(C2H3O2)2 as a MgO nano-template precursor. The prepared corncob-based hierarchical porous carbons (C-HPCs) with desirable micropores and mesopores feature the excellent absorbency of gas (i.e., CO2 and CH4) and solution (i.e., methylene blue (MB)). Increasing the ratio of Mg(C2H3O2)2/corncob enlarged the specific surface area up to 1004 m2/ g, micropore and mesopore volumes, CO2, CH4, and MB adsorption capacities (112, 31 and 230 mg/g after 325 min, respectively). The results indicated that the pore structures of C-HPCs can be easily and suitably controlled by the amount of the template precursor and CO2 activation effecting concurrently, which leads to fascinating adsorption capacity for CO2, CH4, and MB.
        4,200원
        7.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the amendment of Child Welfare Law in 2003, the regional centers for children have been a part of the child welfare system, providing child-care services for families in poverty. In Korea, the regional centers for children were established during the poverty movement in the 1970s and have been developed as childcare providers for poor children since the financial crisis. However, the identity of regional centers for children is being threatened as the universal perspective on caring and the public values of caring services are being strengthened. There has raised a controversy around the role of regional centers for children that provide child-care services for vulnerable families. In addition, the survival of the regional centers for children is being threatened due to some issues regarding the content of their program as it is similar to those of other child-care agencies, the lack of cooperation among the ministries of government addressing public needs for child-care services, the poor working conditions of center employees, and the poor quality of services. The purpose of this study is to examine the formation process of the regional centers for children. After that, we discuss the current issues of the regional centers for children and seek alternatives that can settle the problems and respond properly to social changes.
        4,300원
        8.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature (600–850°C) on the CO2 adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of 1488 m2 g–1 was achieved at an activation temperature of 800°C (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to 850°C. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, CO2 adsorption isotherms showed that AC-800 exhibited the best CO2 adsorption capacity of 110 mg g–1 at 298 K and 1 bar.
        4,000원
        9.
        2015.06 구독 인증기관·개인회원 무료
        Towards the 21st century, the whole world is regarded as one market. Globalization is spreading all over the world as many cosmetics companies pioneering new market abroad, overcoming relatively limited domestic markets. Korean cosmetics companies are not the exception and they are aiming Chinese consumer market, the largest one in Asia, which is growing steadily since government’s open door policy. So, the necessity to compare and figure out the difference between Korean and Chinese consumer’s cosmetics buying behavior is very high for those companies that have their eyes on the Chinese Market. Therefore, the purpose of this study is to compare buying behavior between Korean and Chinese female consumers related to Korean cosmetics brand level. Cosmetics buying behavior is examined in 4 areas; purchasing motives, information sources, purchasing criteria, and the level of satisfaction. Subjects were selected through a convenient sample technique and a questionnaire was developed in Korean and Chinese by translation and back translation method. Data were collected from the sample of 187 out of 233 in Beijing for Chinese female consumers, and 188 out of 200 in Pusan for Korean female consumers. Respondents’ age varied from 20’s to 50’s. Korean cosmetics brands were divided into high /low levels; low brand level included Micha, The face shop, and Laneige while high brand level included Sulhwasu, O’hui, and The history of who. Among many types of cosmetics, this study focused on the basic types of cosmetics product such as lotion, moisture cream, nutrition cream, mask pack with the exception of color based cosmetics products. Data were analyzed by ANOVA and cluster analysis using SPSS 20.0. Respondents were divided into 4 groups: Korean high brand purchasing consumers, Korean Low brand purchasing consumers, Chinese high brand purchasing consumers, and Chinese low brand purchasing consumers. 1. For purchase motives, Chinese consumers affected by Korean celebrities and had more motives to experience Korean cosmetics. To relax and to relieve from stress was the main reasons to buy Korean cosmetics for Chinese high brand consumers. Price was the main reason to buy Korean cosmetics for both low brand purchasing groups. 2. For information sources, Chinese consumers had tendency to collect information from personal relations such as friends and family. Korean and Chinese low brand consumers used internet advertising. Chinese high brand consumers collected information from department salesman. Korean high brand consumers showed lowest use of any kinds of information sources. 3. Korean high brand group put on importance on color and scent as cosmetics purchase criteria. Chinese high brand consumers showed importance on brand image, ingredients, containers/packing, skin fit, and feeling. Korean and Chinese low brand groups have importance on brand image, ingredients, and skin fit. 4. Concerned satisfaction level, Korean high brand group showed lowest satisfaction level. Chinese consumers had satisfied with container design and feelings.