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        검색결과 24

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chlorine is a crucial radionuclide that must be removed in irradiated nuclear graphite. Understanding the interaction between chlorine and graphene-based materials is essential for studying the removal process of 36Cl from irradiated nuclear graphite. In this study, first-principle density functional theory (DFT) was utilized to investigate the adsorption characteristic of chlorine on the original and reconstructed edges of graphene-based materials. Based on the calculation of adsorption energy of the structures after each step of adsorption, the most energetically favorable adsorption routes at four types of edge were determined: Along the armchair edge and reconstructed zigzag edge, the following adatoms would be adsorbed to compensate the distortion induced by the previously adsorbed atom. Meanwhile at the original zigzag edge, chlorine atoms would be adsorbed alternatively along the edge to minimize the repulsion between two adjacent chlorine atoms. The chemical nature of the bonds formed as a result of adsorption was elucidated through an examination of the density of states (DOS) for the two adsorbed chlorine atoms and the carbon atoms attached. Furthermore, to assess the relative stability of the adsorption structures, formation energy of all energetically favorable structures following adsorption was computed. Consequently, the predominant adsorption structure was identified as the reconstructed armchair edge with two chlorine atoms adsorbed. The desorption process of 36Cl2 from the predominant structure following adsorption was simulated, revealing an energy barrier of 1.14 V for desorption. Comparison with experimental results suggests that the chlorine removed from reconstructed armchair edges significantly contributes to the low-temperature removal stage of 36Cl from irradiated nuclear graphite.
        4,000원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        CO2 photocatalytic reduction is a carbon–neutral renewable energy technology. However, this technology is restricted by the low utilization of photocatalytic electrons. Therefore, to improve the separation efficiency of photogenerated carriers and enhance the performance of CO2 photocatalytic reduction. In this paper, g-C3N4/Pd composite with Schottky junction was synthesized by using g-C3N4, a two-dimensional material with unique interfacial effect, as the substrate material in combination with the co-catalyst Pd. The composite of Pd and g-C3N4 was tested to have a strong localized surface plasmon resonance effect (LSPR), which decreased the reaction barriers and improved the electron utilization. The combination of reduced graphene oxide (rGO) created a π–π conjugation effect at the g-C3N4 interface, which shortened the electron migration path and further improved the thermal electron transfer and utilization efficiency. The results show that the g-C3N4/ rGO/Pd (CRP) exhibits the best performance for photocatalytic reduction of CO2, with the yields of 13.57 μmol g− 1 and 2.73 μmol g− 1 for CO and CH4, respectively. Using the in situ infrared test to elucidate the intermediates and the mechanism of g-C3N4/rGO/Pd (CRP) photocatalytic CO2 reduction. This paper provides a new insight into the interface design of photocatalytic materials and the application of co-catalysts.
        4,300원
        3.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulforaphane is a naturally occurring active substance found in vegetables that is known for its potential in preventing and treating cancer. This compound has demonstrated promising effects in inhibiting the growth of various types of cancer, including esophageal, lung, colon, breast, and liver cancer. However, its instability towards pH and heat limits its application in the medical and food industries. To address this challenge, novel drug delivery systems have been developed to improve the stability and efficacy of sulforaphane, making it a more suitable candidate for clinical use in cancer research. In this study, nanocomposite materials were prepared using multi-walled carbon nanotubes (MWCNTs) and chitosan (CS) as base materials, with polydopamine (PDA) acting as a bridge material. The synthesized composite materials were used as drug carriers for the release of sulforaphane. The results of the study showed that the drug loading increased with an increase in the concentration of sulforaphane, indicating that the nanocomposite materials were effective in delivering and releasing the drug. Moreover, a positive correlation was observed between the drug loading and the thickness of the PDA layer. These findings suggest that the use of MWCNTs, CS, and PDA in the development of drug delivery systems can enhance the stability and efficacy of sulforaphane, potentially leading to improved cancer treatment outcomes.
        4,000원
        4.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        N-doping content and configurations have a significant effect on the electrochemical performance of carbon anodes. Herein, we proposed a simple method to synthesize highly N self-doped chitosan-derived carbon with controllable N-doping types by introducing 2ZnCO3 ·3Zn(OH)2 into the precursor. The as-synthesized NC-CS/2ZnCO3·3Zn(OH)2 electrode exhibited more than twice the reversible capacity (518 mAh g− 1 after 100 cycles at 200 mA g− 1) compared to the NC-CS electrode, superior rate performance and outstanding cycling stability. The remarkable improvement should be mainly attributed to the increase of N-doping content (particularly the pyrrolic-N content), which provided more active sites and favored Li+ diffusion kinetics. This study develops a cost-effective and facile synthesis route to fabricate high-performance N self-doped carbon with tunable doping sites for rechargeable battery applications.
        4,000원
        5.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        β-Resin was extracted by solvent separation of refined coal tar pitch. Several analytical methods revealed that β-resin had a better aromatic plane packing structure and a higher number of carbon residues, making it ideal for mesophase transformation. The mesophase transformation process of β-resin (the formation of liquid-crystalline spheres, the growth of mesophase spheres, and the coalescence and disintegration of mesophase spheres) was observed in situ using a polarizing microscope with a hot stage. Moreover, the mesophase transformation mechanism of β-resin was investigated at each transformation stage. The mesophase content and mesophase transformation kinetics were analyzed based on the area method and quinoline insoluble (QI) substitution method. Both methods revealed changes in the mesophase content of β-resin. However, the test results of the two methods were slightly different at the initial stage of mesophase transformation and tended to be consistent during the later stage.
        4,500원
        6.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phytohormones (plant hormones) are a class of small-molecule organic compounds synthesized de novo in plants. Although phytohormones are present in trace amounts, they play a key role in regulating plant growth and development, and in response to external stresses. Therefore, the analysis and monitoring of phytohormones have become an important research topic in precision agriculture. Among the various detection methods, electrochemical analysis is favored because of its simplicity, rapidity, high sensitivity, and in-situ monitoring. Graphene and graphene-like carbon materials have abundant sources, exhibiting large specific surface area, and excellent physicochemical properties. Thus, they have been widely used in the preparation of electrochemical biosensors for phytohormone detection. In this paper, the research advances of electrochemical sensors based on graphene and graphene-like carbon materials for phytohormone detection have been reviewed. The properties of graphene and graphene-like carbon materials are first introduced. Then, the research advances of electrochemical biosensors (including conventional electrochemical sensors, photoelectrochemical sensors, and electrochemiluminescence sensors) based on graphene and graphene-like carbon materials for phytohormone detection is summarized, with emphasis on their sensing strategies and the roles of graphene and graphene-like carbon materials in them. Finally, the development of electrochemical sensors based on graphene and graphene-like carbon materials for phytohormone detection is prospected.
        4,900원
        7.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        How to effectively deal with the polluted water by the pollutant of organic dyes is the world problem. It is of great significance if the organic dyes in the polluted water can be directly turned into the useful materials through a facile approach. Herein, the water which contains the common organic dye, Reactive red 2 (RR2), has been chosen to be the model to synthesize graphene quantum dots (GQDs) by a facile route. The comprehensive characterizations, including TEM (HRTEM), XPS, Raman, PL and UV–Vis. spectra, have been performed to confirm the structures and explore the properties of the synthesized GQDs. Meanwhile, the excellent PL properties and low biotoxicity of the GQDs confer them with the potential applications in the biological fields. When the GQDs are excited by the wavelength of 360 nm, the maximum emission is achieved at 428 nm. It is well demonstrated that the synthesized GQDs are able to detect the Al3+ which causes multiple diseases, such as Parkinson, Alzheimer, kidney disease, and even cancer. The detection range is from 90 to 800 μM, which is different from the reported kinds of the literature. Therefore, this work not only provides an economical and environmental route on solving the universal problem from organic dyes, but also facilitates to advancing the synthesis and application of GQDs.
        4,000원
        8.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Molybdenum disulfide ( MoS2) has been one of the most promising members of transition-metal dichalcogenides materials. Attributed to the excellent electrical performance and special physical properties, MoS2 has been broadly applied in semiconductor devices, such as field effect transistors (FETs). At present, the exploration of further improving the performance of MoS2- based FETs (such as increasing the carrier mobility and scaling) has encountered a bottleneck, and the application of high-κ gate dielectrics has become an effective approach to change this situation. Atomic layer deposition (ALD) enables high-quality integration of MoS2 and high-κ gate dielectrics at the atomic level. In this review, we summarize recent advances in the fabrication of two-dimensional MoS2 FETs using ALD high-κ materials as gate dielectrics. We first briefly discuss the research background of MoS2 FETs. Second, we expound the electrical and other essential properties of high-κ gate dielectrics, which are essential to the performance of MoS2 FETs. Finally, we focus on the advances in fabricating MoS2 FETs with ALD high-κ gate dielectrics on MoS2, as well as the optimized ALD processes. In addition, we also look forward to the development prospect of this field.
        5,200원
        9.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The hybridization of graphene with magnetic nanoparticles has endowed graphene with increasing interest as the adsorbent for wastewater treatment. However, its fabrication often involves a multi-stepped chemical synthesis process. In this work, we demonstrate a facile, one-step, and solvent-free approach to fabricate Fe3O4 nanoparticle-anchored Laser-Induced Graphene ( Fe3O4@LIG) as an efficient adsorbent by direct laser irradiation on a ferric acetylacetonate containing polybenzoxazine film. Raman and X-ray diffraction analysis confirm the graphene component in the adsorbent, and the morphology characterizations show that Fe3O4 nanoparticles are distributed uniformly on LIG with hierarchical meso- and macro-porous structures. Adsorption experiments indicate that Fe3O4@ LIG can adsorb methylene blue (MB) from aqueous solutions in a fast and effective manner, with a maximum adsorption capacity up to 350.9 mg/g. The adsorption kinetics and isotherms are also investigated, which are well-described by the pseudo-second-order model and Langmuir model, respectively. Additionally, Fe3O4@ LIG is also demonstrated with the efficient removal of a variety of organic solvents from water. The favorable adsorption behavior of Fe3O4@ LIG is attributed to its unique porous structure and the molecular interactions with adsorbates. On the other hand, Fe3O4@ LIG has high magnetic property, and therefore, it could be easily recovered from water and well regenerated for repeated use. With the efficient adsorption of organic pollutants, magnetic separability, and good
        5,200원
        10.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A porous-carbon material UiO-66-C was prepared from metal–organic frameworks UiO-66 by carbonization in inert gas atmosphere. Physicochemical properties of UiO-66-C materials were well characterized by Powder X-ray diffraction (PXRD), Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), Raman spectrometer, N2 adsorption/ desorption isotherms (BET), and the adsorption properties of the products were studied UiO-66-C has a high specific surface area up to 1974.17 m2/ g. Besides, the adsorption capacity of tetracycline could reach 678.19 mg/g, the adsorption processes agreed well with the pseudo-second-order kinetic model and Langmuir isotherm model.
        4,000원
        12.
        2020.11 구독 인증기관 무료, 개인회원 유료
        Product labels are one way for advertisers to provide information to purchasers on product quality (Atkinson & Rosenthal, 2014). Label policies have been issued to promote information disclosure on food products in some developed countries. Recent years have also seen increasing attempts to promote healthy eating in emerging markets. In China, nutrition labels became mandatory under the nutrition labeling acts. The laws require nutrition information to be presented at the point of purchase as well as in establishments where food is prepared or consumed. Additionally, similar actions were taken by India (India Ministry of Health and Family Welfare, 2011), Mercosur members and in South Africa (Brazilian Ministry of Health, 2012; Institute of Food Technologists [IFT], 2011).
        3,000원
        14.
        2018.07 구독 인증기관 무료, 개인회원 유료
        Product labels are one way for advertisers to provide information to purchasers on product quality (Atkinson & Rosenthal, 2014). Label policies have been issued to promote information disclosure on food products in some developed countries. Recent years have also seen increasing attempts to promote healthy eating in emerging markets. In China, nutrition labels became mandatory under the nutrition labeling acts. The laws require nutrition information to be presented at the point of purchase as well as in establishments where food is prepared or consumed. Additionally, similar actions were taken by India (India Ministry of Health and Family Welfare, 2011), Mercosur members and in South Africa (Brazilian Ministry of Health, 2012; Institute of Food Technologists [IFT], 2011). While nutritional labeling has received a lot of attention both in academia and from the press, some key gaps remain in the nutrition labeling literature. First, a great deal of marketing research has focused on consumer responses (e.g., Balasubramanian & Cole, 2002; Hieke & Taylor, 2012; Ippolito & Mathios, 1995; Parker & Lehmann, 2014; Shah, Bettman, Ubel, Keller, & Edell, 2014) and firm responses (e.g., Moorman 1998; Moorman, Du, & Mela, 2005; Moorman, Ferraro, & Huber, 2012) to nutrition labeling laws. Although stock market investors express greater interest in information about nutrition issues that can be integrated into financial analyses (Global Access to Nutrition Index [ATNI] Investor Statement, 2013), the issue of how standardized information requirements affect investors’ responses in financial markets has been understudied. As used here, standardized product-information disclosure refers to a requirement to present facts about firms’ offerings in a common format using uniform metrics (Moorman et al. 2012). Understanding the extent to which investors consider product information-disclosure polices when they make investment decisions is important because a company’s financial health is not only the ultimate measure for the success or failure of any strategic initiative (Luo & Bhattacharya, 2009), but also one of the most important measures of public policy effectiveness (Joshi & Hanssens, 2010; Srinivasan & Hanssens, 2009; Schwert, 1981). Moreover, urgent concerns have spilled over from the product market to the financial market (Chen, Ganesan, & Liu, 2009) due to the enormous economic costs and damage to firms’ reputations in product-harm crises (e. g., melamine contamination in several Chinese brands of infant milk powder) (Ngo, 2014). Another gap in the literature is how nutritional-labeling requirements affect emerging markets. In contrast to the situation in long-developed countries, emerging markets are subject to different pressures for food marketers and thus a distinctive environment surrounds the regulation of food product labeling. In China, food safety and quality is considered an urgent concern, and the issue has forced regulators and companies to take action (Yan, 2008). Unlike mature stock markets, the majority of investors in China are individuals (Chen, Li, & Shi, 2010). The Chinese markets are under-regulated and deficient in gathering and disseminating information to private or public organizations, and it is difficult for listed firms with insufficient records to form reputations (Singh et al., 2005). As a result, information asymmetry is accentuated and imperfect signals released from firms highly impact investor decisions. Thus, examining the effectiveness of labeling requirements in developing economies is important as is comparing these results to those found in more developed countries. Despite the importance of the issue in emerging markets, empirical work for investigating investor response to the public policy of nutrition labeling (Ghani, & Childs, 1999) or firms’ nutrition claim strategies (Cao & Yan, 2016) has been restricted in developed markets (e.g., the U.S.). Little is understood the changes in corporate financial performance because of regulations requiring product information disclosure in emerging markets. As a result of the pressures for consumer protection and regulation, it is increasingly important for policy makers to be able to understand the financial consequences of such regulation because of information disclosure policies (Moorman et al., 2005). Thus, an additional contribution of this study is to help better inform the policy debate in emerging markets. To fill these research gaps, we investigated the influence of the influx of standardized product information on the stock market. Specifically, we conducted an event study to examine the effect on firms’ stock values from the issuance of the food nutrition label acts (FNLAs) in China, a fast-growing emerging market. The acts require food manufacturers to provide standardized nutritional information on pre-packaged food labels. This study contributes to the marketing literature on the financial impact of regulation in emerging markets. In China, on the day the FNLA was issued, they were associated with positive abnormal stock returns of related firms. This result is contrary to the study by Ghani and Childs (1999) that reported that the NLEA passage showed a negative impact on firms’ stock prices. Second, the financial value from the issuance of regulations was strengthened by three marketing leverages—advertising, donations, and R&D. Finally, although Moorman et al. argued that the NLEA increased the number of small-share firms exiting the U.S. market (Moorman et al., 2005), we found that in the short term, large firms benefited less than small firms from product information disclosure in China’s stock market. These findings provide empirical evidence that regulatory controls create changes in shareholder wealth and provide an assessment of the financial market’s perceptions regarding the role of mandatory product- information disclosure in future corporate growth. In addition, evidence of the effects of regulatory changes on wealth is of significant value to policymakers and market participants as they evaluate the benefits and costs of information disclosure in emerging markets.
        3,000원
        15.
        2016.07 구독 인증기관·개인회원 무료
        This research explored how experiencing a country’s cultural heritage influences consumers’ authenticity evaluation of its luxury brands. It showed authenticity was culturally constructed and perception was influenced by marketing means selectively exposing the consumers to different brand attributes. It contributes to transcultural research by linking cultural attributes to brand authenticity attributes.
        16.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The wind field and precipitable water vapor over the Tibetan Plateau are analyzed using the numerical model WRF. The spatial and vertical distributions of the relevant meteorological factors are summarized, providing evidence for selecting and further evaluating an astronomical site. This study serves as a further demonstration towards astro-climate regionalization, and provides us with an essential database for an astronomical site survey over the Tibetan Plateau.
        3,000원
        17.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Most of the stars in the Galaxy are in binary systems. Binaries should be possible as the hosting stars of planets. Searching for planetary companions to binaries, especially evolved close binary stars, can provide insight into the formation and the ultimate fate of circumbinary planets and shed light on the late evolution of binary stars. In order to do this, we have chosen some post common envelope binaries including sdB-type eclipsing binaries and detached WD+dM eclipsing binaries as our targets and monitored them for several years. In this paper, we will present some of our new observations and results for three targets, NSVS 07826147, NSVS14256825 and RR Cae.
        3,000원
        18.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        Close binary stars are so close that one component has an effect on the evolution of the other. But how do they form and evolve? This is an unsolved problem. One speculation is that the binary is a part of a hierarchical triple and its orbit shrinks due to interaction with the third component. Therefore, searching for and investigating tertiary components, especially close-in ones, in close binary stars are important for understanding their origin, as well as to test theories of star formation and stellar dynamical interaction.
        19.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Several contact binary systems in four stellar clusters or their fields are reported here; NGC7789-V12, EP Cep and ES Cep in NGC188, NGC104-V95 and V710 Mon. Their multiple light curves were analyzed by the 2010 version of the W-D code, and their physical parameters were obtained.
        3,000원
        20.
        2011.05 구독 인증기관 무료, 개인회원 유료
        Light emitting diode(LED) plays important role in illumination applications such as general lighting, automotive, and outdoor lights due to their high reliability and energy saving elements. The long lifetime is one of the main advantages of LED and thus, the Accelerated Life T(ALT) is used to help achieving the target life time. This paper presents the investigation of ALT models and failures for LED in recent literatures. LED reliability improvement technologies will be discussed finally.
        4,000원
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