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        검색결과 679

        102.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Preparation of activated carbons from wood waste including northern hardwood pins-fines and wood dust was conducted and then compared through the following methods: physical pyrolysis and CO2 activation, vacuum pyrolysis and CO2 activation, CO2 gasification, and vacuum CO2 gasification processes. Experimental results show that chars and activated carbons with high surface area and pore volume are produced from wood waste through a vacuum CO2 pyrolysis/gasification process. The effects of operation variables of vacuum pyrolysis/gasification on the properties of chars and activated carbons were investigated to identify and optimize the temperature, heating time, and heating rate. The optimized vacuum CO2 gasification conditions were found to be a temperature of 800 °C, a heating rate of 20 °C/min, and a holding time of 2 h respectively. The prepared wood-chars and activated carbons were characterized by nitrogen physisorption, scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectra determined any changes in the surface functional groups produced during different preparation stages.
        4,900원
        103.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        DLC has been attractive as semiconductor materials for solar cell due to its biological friendliness, flexible microstructures, and especially its tunable band gap. In order to fabricate high-efficiency multiband gap solar cell, it is important to control the sp3/ sp2 bonds ratio of DLC film corresponding to optical band gap (Eg). There are many references reporting the relations among the fabrication conditions, Eg, sp3/ sp2, and ID/ IG. However, a more comprehensive database is needed for controllable fabrication. Especially, the quantitative relationship of sp3/ sp2 ratio to Eg of DLC film by PECVD is unclear. In this paper, 36 sets of DLC films were fabricated by RF-PECVD. Characterization methods of XPS, Raman spectroscopy, and IR absorption have been used to determine the sp3/ sp2 ratio of DLC films. UV/visible light absorption method has applied to evaluate Eg. The Eg obtained is in the range 1.45–3.0 eV. Our results agree well with the references. The XPS spectra gives a linear relationship as Eg = − 0.161 (± 0.136) + 26.095 (± 1.704) · {sp3 (XPS)/sp2}, the Raman spectra shows a linear function that Eg = 1.327 (± 0.046) + 0.428 (± 0.036) · (ID/IG), as well as the FTIR analysis demonstrates that Eg = − 0.492 (± 0.093) + 0.464 (± 0.044) · {sp3 (FTIR)/sp2}.
        4,200원
        106.
        2021.10 구독 인증기관·개인회원 무료
        108.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, the significance of small talk in institutional context has been receiving considerable attention in the field of sociolinguistics and communication studies. While scholars seem to agree on its social functions that facilitate the accomplishment of the institutional goal of the encounter by “oiling interpersonal wheels”, the wide range of interpersonal relationships enacted in small talk in institutional encounter has not been subject to rigorous research attention yet. By applying Conversation Analysis (CA), this study compares small talk in an on-campus coffee shop within two different interpersonal relationship groups: new customer-barista and regular customer-barista. Data were drawn from 35 video recordings of service encounters interaction involving both native and non-native English-speaking customers at a college-sponsored café. The findings show that small talk with a new customer strictly adhered to coffee-related topics and tended to be quickly curtailed by one or both interlocutors, as suggested by the alignment of their institutional roles of barista-customer. In contrast, small talk between a regular customer and a barista consisted of exchanges on a wide variety of topics. This finding suggests that the topic of conversation is a potential indicator of relationship through a shift of alignment to the interactional roles of ‘friend-friend’.
        8,000원
        109.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        중국은 1979년 이후로 한자녀정책을 주요 정책으로 추진해왔고, 이로 인해 저출산 사회로 전환되었 다. 또한 발전된 보건과 의료기술로 노인들의 수명이 급격히 늘어나면서 중국의 고령화율 역시 급증하 였다. 이렇듯 수발이 필요한 고령인구는 급증하였으나, 현재 중국에는 이들을 돌볼 돌봄인력이나 인프 라가 턱없이 부족한 상태이다. 본 연구는 이러한 노인수발 문제를 해결하기 위한 제도적 해법으로 노인 장기요양보험에 주목한다. 본 연구는 중국 노인장기요양보험제도의 도입과정과 시범사업 등을 살펴본 후, 노인장기요양보험제도 도입의 선도국가인 한국으로부터 어떤 정책교훈을 얻을 수 있는지 살펴보았 다. 본 연구는 연구를 수행함에 있어 주로 문헌연구 분석을 사용하였다. 본 연구는 두 가지 의의를 갖는다. 첫째, 중국 노인장기요양보험제도의 시범사업을 개관함으로써 그 흐름은 물론 그에 관한 기초 자료를 제공하고 있다. 둘째, 중국의 노인수발 문제를 연구함에 있어 기존 연구들에서 찾아볼 수 없는 비교사회정책학적 접근법, 특히 동아시아 사회복지에 대한 비교연구를 수행하였다.
        5,200원
        110.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The carbon spheres (CSs) synthesized by an ultrasonic-spray pyrolysis method were activated for supercapacitor electrode. There are plenty of cracks on the surface of the activated carbon spheres (ACSs), which expend with increasing the activation temperature and activator dosage. The specific capacitance of ACSs increases with the activation temperature and activator dosage and reach to maximal value at certain conditions. Importantly, the ACS sample activated at relatively low activation temperature (600 °C) and 7 of mass ratio of KOH to CSs has the highest specific capacitance (about 209 F g− 1 at 50 mA g− 1 of current density) and indicates the excellent cycling stability after 1000 consecutive charge–discharge cycles. Furthermore, the graphene sheets could be found in the samples that were activated at 1000 °C. And the electrode prepared by the sample has the very low series resistance because of the excellent conductivity of the formed graphene sheets.
        4,000원
        111.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Highly Oriented Pyrolytic Graphite (HOPG) was half covered using aluminum foil and exposed to irradiation with 70 keV C+ ions at room temperature (~ 25 ℃). The surface layer (height = 178.3 ± 4.7 nm) of the irradiated area was destroyed, many nano-sized dendritic protrusions were observed and smooth inner layer was exposed. The peak area ratio (ID/IG) in Raman spectra increased after ion irradiation, indicating that a change in atomic structure and transformation from the sp2 to sp3 phase. The mechanical properties were explored using atomic force microscopy in peakforce mode, which revealed that the Young’s modulus of the exposed inner layer was similar to unirradiated area, while the Young’s modulus of the dendritic protrusions was higher. There findings provided further understanding of the HOPG at nanoscale, which is of value for practical implementation in related fields.
        4,000원
        112.
        2021.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Well-crystallized vanadium pentoxide V2O5 thin films are fabricated on MgO single crystal substrates by using pulsed-laser deposition technique. The linear optical transmission spectra are measured and found to be in a wavelength range from 300 to 800 nm; the data are used to determine the linear refractive index of the V2O5 films. The value of linear refractive index decreases with increasing wavelength, and the relationship can be well explained by Wemple’s theory. The third-order nonlinear optical properties of the films are determined by a single beam z-scan method at a wavelength of 532 nm. The results show that the prepared V2O5 films exhibit a fast third-order nonlinear optical response with nonlinear absorption coefficient and nonlinear refractive index of 2.13 × 10−10 m/W and 2.07 × 10−15 cm2/kW, respectively. The real and imaginary parts of the nonlinear susceptibility are determined to be 3.03 × 10−11 esu and 1.12 × 10−11 esu, respectively. The enhancement of the nonlinear optical properties is discussed.
        3,000원
        113.
        2021.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인류는 석유 및 가스 자원의 확보를 위하여 전 세계 해역에 해양플랜트 구조물을 설치해 왔다. 하지만 이들의 수명은 약 30년으로 약 30%의 해양플랜트 구조물들이 수명을 다한 채 전 세계해역에 폐기물로 방치되어 있다. 이미 오랫동안 선진국을 중심으로 노후화된 해양플랜트 구조물의 철거 또는 재활용방안에 대해 논의해 왔으며, 미국 및 유럽에서는 인공어초 재활용 방법을 이용하여 해양플랜트 구조물을 해체하고 있다. 현재 해양플랜트 해체시장은 2020년에서 2025년까지 약 5% 이상의 연평균 복합 성장률로 증가할 것으로 예상하며, 그중 가장 빠르게 성장하고 있는 중국의 해양플랜트 해체시장은 2027년까지 약 16억 달러까지 성장할 것으로 예측하고 있다. 이러한 배경을 바탕으로 본 논문은 해양플랜트 구조물 해체에 관한 국제법제 현황 및 문제점에 대해 알아보고, 나아가 현재 해양플랜트 해체산업을 중점적으로 육성하고자 하는 중국의 국내 법제를 검토하고자 한다.
        7,700원
        114.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        “도덕교육은 학생과 가깝고 직업과 가까우며 사회와 가까운 실천을 중시해야 한다.” 그래서 직업학교의 도덕교육은 학생의 인지능력과 전공특징에 따라 과감하게 혁신적인 교육 디자인을 하고, 예술교육의 내용과 형식을 차용해야 한다. 그 형상성으로 도덕교육을 그 모습을 생생하고 생동감 있게 만들어야 한다. 학생들의 감정적 공감을 불러일으키고 교육 효과를 향상시키며 학생의 종합적인 자질을 향상시켜야 한다. 그러므로 도덕교육은 그 과목의 기본적 문제를 핵심으로 삼고 학생들이 관련 지식을 배우는 것부터 시작함으로써 삶에 뿌리를 두어야 한다. 학생들이 삶을 관찰하고, 삶을 느끼고, 삶을 경험하는 과정에서 긍정적인 삶의 태도를 형성하여 도덕교육의 ‘지식, 감정, 의도, 믿음, 그리고 실천’의 통합을 실현할 수 있도록 해야 한다.
        5,400원
        115.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, nitric acid oxidation with varied treatment temperature and time was conducted on the surfaces of polyacrylonitrile- based ultrahigh modulus carbon fibers. Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and surface tension/dynamic contact angle instruments were used to investigate changes in surface topography and chemical functionality before and after surface treatment. Results showed that the nitric acid oxidation of ultrahigh modulus carbon fibers resulted in decreases in the values of the crystallite thickness Lc and graphitization degree. Meanwhile, increased treating temperature and time made the decreases more obviously. The surfaces of ultrahigh modulus carbon fibers became much more activity and functionality after surface oxidation, e.g., the total surface energy of oxidized samples at 80 °C for 1 h increased by 27.7% compared with untreated fibers. Effects of surface nitric acid oxidation on the mechanical properties of ultrahigh modulus carbon fibers and its reinforced epoxy composites were also researched. Significant decreases happened to the tensile modulus of fibers due to decreased Lc value after the nitric acid oxidation. However, surface treatment had little effect on the tensile strength even as the treating temperature and processing time increased. The highest interfacial shear strength of ultrahigh modulus carbon fibers/epoxy composites increased by 25.7% after the nitric acid oxidation. In the final, surface oxidative mechanism of ultrahigh modulus carbon fibers in the nitric acid oxidation was studied. Different trends of the tensile strength and tensile modulus of fibers in the nitric acid oxidation resulted from the typical skin–core structure.
        4,500원
        116.
        2021.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Bi2MoO6 (BMO) via the structure-directing role of CO(NH2)2 is successfully prepared via a facile solvothermal route. The structure, morphology, and photocatalytic performance of the nanoflake BMO are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectrum analysis (PL), UV-vis spectroscopy (UVvis) and electrochemical test. SEM images show that the size of nanoflake BMO is about 50 ~ 200 nm. PL and electrochemical analysis show that the nanoflake BMO has a lower recombination rate of photogenerated carriers than particle BMO. The photocatalytic degradation of tetracycline hydrochloride (TC) by nanoflake BMO under visible light is investigated. The results show that the nanoflake BMO-3 has the highest degradation efficiency under visible light, and the degradation efficiency reached 75 % within 120 min, attributed to the unique hierarchical structure, efficient carrier separation and sufficient free radicals to generate active center synergies. The photocatalytic reaction mechanism of TC degradation on the nanoflake BMO is proposed.
        4,000원
        117.
        2021.06 구독 인증기관 무료, 개인회원 유료
        Qianziwen was written by Zhou Xingsi. It spread to ancient Korea and had a major influence on Korean literary history. An immediate effect was that many written and printed versions appeared throughout Korea. Some Korean scholars imitated and translated the culturally alien texts of Qianziwen to facilitate the process of Chinese education in Korea. An indirect effect was to encourage the production of books with Korean characteristics. One example of this is the development of dictionary compilations in ancient Korea. This is a special phenomenon in terms of cultural exchanges between China and Korea, and is invaluable for the understanding of the spread of Chinese characters and classics overseas.
        6,000원
        118.
        2021.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The 1982 United Nations Convention on the Law of the Sea admitted legislation and enforcement jurisdiction carried out by the flag state. However, the emergence of substandard ships and the growing number of ship accidents at sea indicate that flag state jurisdiction is far from effective. Four aspects of these failures are examined in this paper. Confronted with the failure of flag state jurisdiction, port states have devised a subsidiary remedy to ensure their national interests and restore the effectiveness of flag state jurisdiction. A problem hereunder arises because non-explicit permission was given to port states to prosecute substandard ships. Thus, this paper further analyses four aspects of port state jurisdiction. The authors aim to analyse the failures and remedies associated with state jurisdiction over ships. It reviews the scope and deficiency of state jurisdiction in combatting substandard ships and illicit activities at sea. This paper also addresses the importance of port state control, regional memorandums of understanding and international conventions.
        6,700원
        119.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a new method of rapid preparation of carbon nanotube (CNT) solution with highly dispersed morphology by free arc excitation is proposed, which shortens the time of the preparation of CNT solution with low concentration. The principle is that the high-energy flow density heat generated by the free arc makes the vaporizable substance coated on the surface of CNTs vaporize rapidly, and then generates the bulk increasing motion, which makes the CNTs aggregates dispersed, and finally forms the CNTs gas-phase dispersion monomer with high dispersion or the cross-linking morphology of few CNTs. In this paper, the influence of gum Arabic (GA) and deionized water (DI water) contents in CNTs mixed electrode on the dispersion of CNTs in different environments (gas phase and liquid phase) is explored. In the limited case of this work, the dispersion effect is better when the mass ratio of CNTs, GA and DI water is 1:0.04:3.96 in the liquid-phase environment. The preparation method reported in this work is expected to be a rapid way to obtain low-concentration nanodispersion.
        4,000원
        120.
        2021.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To solve the common problems of concrete preparation in low-temperature environments, calcium formate (C2H2O4Ca), anhydrous sodium sulfate (Na2SO4), triethanolamine (C6H15O3N), calcium bromide (CaBr2), and triisopropanolamine (C9H21NO3) are selected as early strength agents and mixed with C40 concrete in different dosages under low-temperature environments of 5 oC and 10 oC to develop a high-efficiency low-temperature compound early strength agent based on the effect of single-doped early strength agents. The effects of the compound early strength agent on the early strength of the concrete, the cement paste setting time, and cement fluidity at 5 oC and 10 oC are investigated, and the corresponding reaction mechanism is discussed from the perspective of micro-products. The best compound early strength agent ratio is found to be 2% of calcium formate + 0.08 % of TEA (C6H15O3N). The compound early strength agent effectively promotes the formation of hydration products, such as Ca(OH)2 and C-S-H gel. In comparison with the control group, the strength of the concrete cured for 18 h, 1 d, 3 d, and 7 d under simulated natural conditions at 5 oC increases by 700%, 540%, 11.4 % and 10 %, respectively, whereas at 10 oC, the corresponding values are 991%, 400%, 19.6 % and 11 %, respectively. The strength of the concrete at each age is close to the normal temperature standard of the curing strength. The addition of the compound early strength agent causes a reduction in cement fluidity and initial and final setting times, and also yields a good effect on the porosity of the early concrete.
        4,600원