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        검색결과 576

        41.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explored the role of written languaging (WL) in response to automated written corrective feedback (AWCF) in L2 accuracy improvement in English classrooms at a university in China. A total of 254 freshmen enrolled in intermediate composition classes participated, and they wrote 4 essays and received AWCF. A half of them engaged in WL after receiving correction, while the other half did not. To measure whether WL could contribute to L2 accuracy improvement, error correction tests were conducted three times. AWCF targeted all types of errors, but the study focused on investigating six language features (nouns, conjunctions, subject-verb agreement, sentence constituents, articles, and prepositions) known as the most frequent errors intermediate students make. The results proved that WL had a positive effect on accuracy improvement overall. However, when individual language features were considered separately, the effects were not the same. The inherent complexity of the features along with L1 influence appeared to affect the effects of WL for accuracy improvement.
        5,700원
        42.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g− 1 after 200 cycles at a current density of 200 mA g− 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.
        4,200원
        43.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A promising approach to enhance catalytic performance of supported heterogeneous nano-metal catalysts is to uniformly disperse active nanoparticles on the support. In this work, N-doped carbon-modified graphene (G@NC) nanosheet is designed and prepared to anchor Pd–Fe bimetallic nanoparticles (Pd–Fe/G@NC). The N-doped carbon modification on graphene surface could construct a sandwich-like structure (G@NC), which not only prevented the re-stacking of graphene nanosheets but also provided confined space for stable anchoring of bimetallic Pd–Fe nanoparticles. Benefitted from the unique structural property and synergetic effect of metal Pd and Fe species, the as-obtained Pd–Fe/G@NC composite displays excellent catalytic activity toward 4-nitrophenol reduction reaction with a turnover frequency of 613.2 min− 1, which is far superior to that of the mono-metal counterparts (Fe/G@NC and Pd/G@NC). More importantly, Pd–Fe/G@NC catalyst also exhibits favorable catalytic performance in the reduction of other nitroaromatic compounds (nitrobenzene, 4-nitrotoluene, 4-chloronitrobenzene, and so on). In addition, Pd–Fe/G@NC can catalyze the oxidation of furfuraldehyde to furoic acid with a high yield of 88.64%. This work provides a new guide for rationally designing and developing advanced supported heterogeneous bimetallic catalyst.
        4,200원
        44.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The evolvement in the microstructure and electrical properties of PAN-based carbon fibers during high-temperature carbonization were investigated. The study showed that as the heat treatment temperature increases, the change of carbon fiber resistivity around 1100 °C can be divided into two stages. In the first stage, the carbon content of the fiber increased rapidly, and small molecules such as nitrogen were gradually released to form a turbostratic of carbon crystal structure. The resistivity dropped rapidly from 3.19 × 10− 5 Ω·m to 2.12 × 10− 5 Ω·m. In the second stage, the carbon microcrystalline structure gradually became regular, and the electron movement area gradually became larger. At this time, the resistivity further decreases, from 2.12 × 10− 5 Ω·m to 1.59 × 10− 5 Ω·m. During carbonization, the tensile strength of carbon fiber first increased and then decreased. This is because the irregular and disordered graphite structure is formed first. As the temperature rose, the graphite layer spacing decreased and the grain thickness gradually increases. The modulus also gradually increased.
        4,000원
        45.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The conversion of CO2 into solar fuels by photocatalysis is a promising way to deal with the energy crisis and the greenhouse effect. The introduction of oxygen vacancy into semiconductor has been proved to be an effective strategy for enhancing CO2 photoreduction performance. Herein, TiO2- x nanostructures have been prepared by a simple solvothermal method and engineered by the reaction time. With the prolonging of reaction time, the oxygen vacancy signal gradually increases while the band gap becomes narrow for the as-synthesized TiO2- x nanostructures. The results show that the TiO2- x-6 h, TiO2- x-24 h, and TiO2- x-48 h samples have the main product of CH4 (more) and CO (less) for CO2 photoreduction. Among the three oxygen vacancy photocatalysts, the TiO2- x-24 h sample shows the highest CH4 generation rate of 41.8 μmol g− 1 h− 1. On the basis of photo/electrochemical measurements, the TiO2- x-24 h sample exhibits efficient electron–hole separation and charge transfer capabilities, thus allows much more electrons to participate in the reaction and finally promotes the photocatalytic CO2 reduction reaction. It further confirms that the optimization of oxygen vacancy concentration could facilitate the photoinduced charge separation and accordingly improve photocatalytic CO2 conversion.
        4,000원
        46.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Subunit vaccines are being developed as a potential therapy for preventing microbial pathogen infection. In this study, the immunogenicity of recombinant Brucella (B.) abortus Fe/Mn superoxide dismutase (rFe/Mn SOD) protein as a subunit vaccine against B. abortus was investigated in BALB/c mice model. Brucella Fe/Mn SOD gene was cloned into a pcold-TF DNA vector. The bacterial recombinant protein was expressed using the Escherichia coli DH5α strain with a size of 82.50 kDa. The western blotting assay showed that rFe/Mn SOD reacted with Brucella-positive serum, indicating the potential immunoreactivity of this recombinant protein. After the second and third vaccinations, the peripheral CD4+ T cell population was increased significantly in the rFe/Mn SOD-immunized mice group compared to the PBS control group. Moreover, immunization of this recombinant protein increased the CD4+ T cell population from the first vaccination to the third vaccination. Meanwhile, the CD8+ T cells were slightly enhanced after the second vaccination compared to the first vaccination and compared to control groups. Fourteen days after the bacterial infection, the splenomegaly and the number of bacteria in the spleen were evaluated. The result showed that both rFe/Mn SOD and positive control RB51 decreased the bacterial replication in the spleen and the splenomegaly compared to control groups. Altogether, these results suggested that rFe/Mn SOD could induce host immunity against B. abortus infection.
        4,000원
        49.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Enhancing the capacitive deionization performance requires the inner structure expansion of porous activated carbon to facilitate the charge storage and electrolyte penetration. This work aimed to modify the porosity of coconut-shell activated carbon (AC) through CO2 activation at high temperature. The electrochemical performance of CO2- activated AC electrodes was evaluated by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy, which exhibited that AC-800 had the superior performance with the highest capacitance of 112 F/g at the rate of 0.1 A/g and could operate for up to 4000 cycles. Furthermore, in the capacitive deionization, AC-800 showed salt removal of 9.15 mg/g with a high absorption rate of 2.8 mg/g min and Ni(II) removal of 5.32 mg/g with a rate close to 1 mg/g.min. The results promote the potential application of CO2- activated AC for desalination as well as Ni-removal through capacitance deionization (CDI) technology.
        4,000원
        50.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For graphene oxide (GO) composite hydrogels, a two-dimensional GO material is introduced into them, whose special structure is used to improve their properties. GO contains abundant oxygen-containing functional groups, which can improve the mechanical properties of hydrogels and support the application needs. Especially, the unique-conjugated structure of GO can endow or enhance the stimulation response of hydrogels. Therefore, GO composite hydrogels have a great potential in the field of wearable devices. We referred to the works published in recent years, and reviewed from these aspects: (a) structure of GO; (b) factors affecting the mechanical properties of the composite hydrogel, including hydrogen bond, ionic bond, coordination bond and physical crosslinking; (c) stimuli and signals; (d) challenges. Finally, we summarized the research progress of GO composite hydrogels in the field of wearable devices, and put forward some prospects.
        4,900원
        51.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chlorine dioxide (ClO2) has recently emerged as an ideal disinfectant and has shown a wide range of antimicrobial activities in various pathogenic microorganisms. In this study, the virucidal effect of ClO2 at low concentration (0.02 ppm) and higher concentration (0.06 – 0.09 ppm) against Adenovirus and Herpesvirus was evaluated based on the NF T 72-281 and ASTM 1053-11 standard methods at different exposure times. The virus suspension was dried onto the carrier and then exposed to gaseous ClO2 (gClO2) at 22 ± 2∘C. For Adenovirus, exposure at a low concentration of ClO2 at the middle height resulted in the average log10 reduction of 0.95, 2.65, and 5.30 after 1, 3, and 6 h post-exposure (pe), respectively. Moreover, more than 4-log10 reduction was achieved at 4 and 6 h pe with higher concentrations of ClO2. On the other hand, the antiviral activity of gClO2 at the middle height was also effective against Herpesvirus. In particular, at 1 h pe, a less than 4-log10 reduction was observed at all examined concentrations of ClO2, whereas exposure for 3 and 6 h (with low concentration) or 2 h (with higher concentration) inactivated completely viruses attached to the carrier. These results suggested that ClO2 fumigation is a potential alternative method for disinfecting healthcare facilities, high-containment laboratories, and households with a safe concentration for human health.
        4,000원
        52.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.
        4,300원
        53.
        2022.06 구독 인증기관 무료, 개인회원 유료
        E-commerce has been rapidly growing in China which has quickly become the largest e-commerce market in the world. However, this has also led to an increasing number of e-commerce disputes. In practice, such disputes are resolved by online dispute resolution. As the results of online dispute resolution are not legally binding, however, China’s online arbitration procedure has been criticized especially regarding the conflicts between party autonomy and institutional autonomy. China’s judicial reviews would claim that such awards cannot be enforced. Therefore, there is a call to make online arbitral awards enforceable and to expand the application of online arbitration to more e-commerce disputes in China. This paper examines how to best analyse and address such conflicts. We explain the importance of arbitral institutions’ autonomy in terms of ensuring access to justice as well as the importance of limiting party autonomy in certain circumstances due to the rise in online disputes.
        6,700원
        55.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Diamond reinforced silicon carbide matrix composites (diamond/SiC) with high thermal conductivity were prepared by tape casting combined with Si vapor infiltration for thermal management application. The effects of the mixing mode of bimodal diamond particles on the microstructure, thermal and mechanical properties of the composites were analyzed. The results reveal that the thermal conductivity of composites is affected significantly by mixing mode of diamond. In general, when the content of large diamond remains constant, adding a slight amount of small diamond was found to be effective in improving the thermal conductivity of the composite. However, excess small diamonds added will decrease thermal conductivity due to its high interfacial thermal resistance. The maximum thermal conductivity of obtained diamond/SiC is 469 W/(m K) when 38 vol% large diamond and 4 vol% small diamond were added. Such a result can be attributed to the formation of efficient heat transfer channels within the composite and sound interfacial bonding between diamond and SiC phase. Diamond/SiC with high thermal conductivity are expected to be the next generation of electronic packaging substrate.
        4,000원
        56.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electrochemical reduction of carbon dioxide to valuable chemicals is a promising way of storing renewable energy through electric-to-chemical energy conversion, while its large-scale application is in urgent need of cheap and high-performance catalysts. Herein, we invent a convenient method to synthesize N-doped porous carbon by ammonia etching the pyrolysis carbon of petroleum pitch. We found the ammonia etching treatment not only increase the pyridinic-N content, but also enlarge the specific surface area of the petroleum pitch-based porous carbon. As a cheap and easily available catalyst for carbon dioxide electroreduction, up to 82% of Faradaic efficiency towards carbon monoxide was obtained at − 0.9 V vs the reversible hydrogen electrode in 0.1 M KHCO3. After a long time electrocatalysis of more than 20 h, the Faradaic efficiency of carbon monoxide remains 80%, indicating the porous carbon as made have an ultra-high stability as catalyst for carbon dioxide reduction. Our work provides a new technology to economically prepare efficient electrocatalysts for carbon dioxide reduction.
        4,000원
        58.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Coal-based graphite has become the main material of emerging industries. The microstructure of coal-based graphite plays an important role in its applications in many fields. In this paper, the effect of carbon disulfide/N-methyl-2-pyrrolidone solvent mixture extraction on the microstructure of bituminous coal-based graphite was systematically studied through preliminary extraction coupled with high-temperature graphitization. The graphitization degree g (75.65%) of the coal residue-based graphite was significantly higher than that of the raw coal-based graphite. The crystallite size La of the coal residue-based graphite was reduced by 47.06% compared with the raw coal-based graphite. The ID/ IG value of the coal residue-based graphite is smaller than that of the raw coal-based graphite. The specific surface area (16.72 m2/ g) and total pore volume (0.0567 m3/ g) of the coal residue-based graphite are increased in varying degrees compared with the raw coal-based graphite. This study found a carbon source that can be used to prepare coal-based graphite with high graphitization degree. The results are expected to provide a theoretical basis for further clean and efficient utilization of the coal residue resources.
        4,000원
        59.
        2022.05 구독 인증기관·개인회원 무료
        Technetium-99 (99Tc) is a challenging radionuclide from presents many problems related to safe disposal. The measurement of 99Tc is of particular interest due to its high mobility, and the fact that it is a beta-emitter with a long half-life (t1/2=2.13×105 years) with long-term radiological effects[1]. As an isotopes of 99Tc, 99mTc has been widely applied for medical diagnosis and medical research. It is reported that the 99mTc has been used in 80% of diagnostic nuclear medicine procedures and almost 30 million examinations are conducted worldwide using this isotope. Because 99mTc has a short half-life of 6 h and decays to 99Tc, monitoring and safe disposal of 99Tc from human urine is very important, and concern is increasing every day as global use of 99mTc has increased by more than 4.5×1014 Bq per week and is increasing continuously[2]. However, the current methods for the detection of this radionuclide in such mdium are time consuming and can not satisfy for the low level urine sample analysis. In this work, a method for rapid determination of 99Tc in urine samples was developed. The sample was firstly pre-treated with K2S2O8 to decompose the organic matters combined with 99Tc in 0.5 mol·L−1 HNO3 medium at 100°C. Then the sample solution was loaded to a TEVA column (2 mL) for 99Tc separation and purification. The target element was finally measured by high resolution inductively coupled plasma mass spectrometry (HR-ICPMS). The developed analytical method was proved to be reliable and can be used to rapid determine low-level 99Tc in urine samples.
        60.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        희생은 아일랜드 민족주의의 중요한 가치이자 독립 투쟁의 수단이기도 했다. 희생은 예이츠 초기희곡 세 작품—『캐슬린백작부인』,『캐슬린 니 훌리한』,『왕의 문지방』—의 주제이다. 이 논문은 이 세 작품을 중심으로 각기 다른 형태의 희생 을 연구한다.『캐슬린백작부인􋺸에서 캐슬린은 가난한 농부들을 구하기 위해 영혼까지 팔고, 『캐슬린 니 훌리한』에서 젊은 농부인 마이클은 아일랜드의 상징인 노파의 부름 에 응해 신부와 가족을 뒤에 두고 노파를 위해 싸우러 떠난다. 『왕의 문지방』에서 국 민시인인 샤나한은 국가평의회 위원이라는 시인의 오래된 권리를 수호하기 위해 목숨 을 희생한다. 이 논문의 목적은 주인공들의 희생의 의미와 그 희생에 대한 예이츠의 태도를 분석하는 것이다.
        5,100원
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