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        검색결과 390

        41.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A facile and efficient method was developed to prepare highly stretchable and conductive graphene conductors with wrinkled structures by the mechanical stretching and shrinking of elastomeric substrates, in which graphene inks were printed on a prestretched elastomeric substrate. Stretchable and exfoliated graphene inks were prepared by mixing graphite and Ecoflex in a shear-assisted fluid dynamics reactor. The resultant graphene conductor exhibited excellent stretchability at 150% strain and high electrical conductivity of 64 ± 1.2 S m− 1. The resistance of the conductor did not change in bent, twisted, and stretched states. The resistance did not change during 10,000 cycles of stretching/releasing, with a maximum strain of 150%. Based on the graphene conductor, a stretchable conductometric sensor with a two-electrode configuration was fabricated to measure impedance changes at different concentrations of electrolyte ions. This sensor exhibited a good and linear sensitivity curve (298.61 Ω mM− 1, R2 = 0.999) in bent and stretched states.
        4,000원
        42.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Because of the massive development of nuclear power plants in China in recent years, China is facing the challenge of radioactive waste disposal. China has established complete regulatory requirements for radioactive waste disposal, but it also has encountered problems and challenges in low-level radioactive waste disposal in terms of management, selection of disposal facility sites, and implementation of a site selection plan. Three low-level radioactive waste disposal facilities that have been operated in China are described, and their activity limits, locations, and capacities are also outlined. The connotations of “regional” and “centralized” disposal policies are discussed in light of the characteristics of the radioactive waste. The characteristics and advantages of the regional and centralized disposal policies are compared. It is concluded that the regional disposal policy adopted in 1992 can no longer meet the current disposal needs, and China should adopt a combination of the two disposal policies to solve the problem of radioactive waste disposal.
        4,000원
        43.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The International Atomic Energy Agency (IAEA) entails independent decision-making for the safety supervision of civil nuclear facilities. To evaluate and review the safety of nuclear facilities, the national regulatory body usually consults independent institutions or external committees. Technical Support Organizations (TSOs) include national laboratories, research institutions, and consulting organizations. Support from professional organizations in other countries may also be required occasionally. Most of the world’s major nuclear power countries adopt an independent nuclear safety supervision model. Accordingly, China has continuously improved upon the construction of such a system by establishing the National Nuclear Safety Administration (NNSA) as the decision-making department for nuclear and radiation safety supervision, six regional safety supervision stations, the Nuclear and Radiation Safety Center (NSC), a nuclear safety expert committee, and the National Nuclear and Radiation Safety Supervision Technology R&D Base, which serves as the test, verification, and R&D platform for providing consultation and technical support. An R&D system, however, remains to be formed. Future endeavors must focus on improving the technical support capacity of these systems. As an enhancement from institutional independence to capability independence is necessary for ensuring the independence of China’s nuclear safety regulatory institution, its regulatory capacity must be improved in the future.
        4,000원
        48.
        2022.09 구독 인증기관·개인회원 무료
        기후변화 시나리오는 기후변화로 인한 미래 영향을 평가하여 피해를 선제적으로 최소화하기 위한 기후변화 대응 및 적응정책 수립을 위한 과학적인 근거로 활용 되어 왔다. IPCC 6차 평가보고서(AR6)에 사용된 SSPs(Shared Socioeconomic Pathways, 공통사회경제경로) 시나리오는 기존 RCP(Representative Concentration Pathways, 대표농도경로) 시나리오에 사용된 복사강제력 개념과 함께 미래의 완화 와 적응 노력에 따른 5개의 사회경제 시나리오를 추가로 고려하였다. 가나는 국가 발전용량의 54%를 수력발전에 의존하고 있어 기후변화에 따른 강수량의 감소로 전력 부족을 경험하고 있다. 또한 강우특성의 변화로 인해 주요 작물인 카사바, 옥수수, 코코아의 생산량이 감소할 것으로 예측된다. 한편, IPCC 6차 보고서의 기 준 시나리오로 채택된 SSPs 시나리오는 5차 보고서에서 채택된 RCPs 시나리오에 비해 대기 중 CO2 농도 전망을 비관적으로 평가하고 있다. Business as usual(BAU) 시나리오(RCP8.5, SSP5-8.5)에 따르면 2050년대 CO2 농도는 RCPs 시나 리오의 경우 541 ppm, SSPs 시나리오는 565 ppm으로 SSPs 시나리오가 RCPs 시나 리오에 비해 대기중 CO2 농도 증가 속도가 빠른 것으로 전망하고 있다. 따라서 본 연구에서는 기후변화 시나리오의 통계적 상세화 방법인 Simple Quantile Mapping(SQM)을 사용하여 Coupled Model Intercomparison Project phase 6(CMIP6) 18개 General Circulation Model(GCM)을 활용하여 가나지역의 미래기후 변동과 불 확실성을 평가하였다.
        49.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pentachlorophenol (PCP), as one of the common pesticide and preservatives, is easily accumulated in living organisms. Considering the high toxicity of PCP, the development of an effective and sensitive inspection method to determine the residual trace amounts of PCP continues to be a significant challenge. Herein, a convenient and sensitive electrochemical sensor is constructed by modifying glassy carbon electrode with cerium dioxide ( CeO2) nanoparticles anchored graphene ( CeO2-GR) to detect trace PCP. Benefiting from the two-dimensional lamellar structural advantages, the extraordinary electron-transfer properties, as well as the intensive coupling effect between CeO2 nanoparticles and graphene, the afforded CeO2- GR electrode nanomaterial possesses excellent electrocatalytic activity for the oxidation of PCP. Under the optimum synthetic conditions, the PCP oxidation peak currents of developed CeO2– GR sample exhibit a wide linear range of 5–150 μM. Moreover, the corresponding detection limit of PCP on the CeO2– GR electrode is as low as 0.5 μM. Apart from providing a promising electrochemical sensor, this work, most importantly, promotes an efficient route for the construction of highly active sensing electrode materials.
        4,000원
        50.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hypercrosslinked polymers HCPs have been widely used as precursors to prepare porous carbon materials because of their highly ordered porous structure and large specific surface area. In this paper, we used a solvothermal method to prepare a hypercrosslinked polymer, and the HCPC-700-A was prepared using an activation method with the hypercrosslinked polymer as the precursor. The effects of different carbon–alkali ratios on the microstructure, composition and electrochemical properties of porous carbon HCP were studied. The results show that the surface of porous carbon HCPC-700-A presents a relatively regular geometric shape, and a large number of pore structures are mainly micro- and mesopores. The specific surface area is 2074.53 m2 g− 1, and the average pore size is between 1.29 and 1.93 nm. Porous carbon HCPC-700-1:2 has excellent electrochemical performance in 1 M H2SO4, and the specific capacitance is up to 464.4 F g− 1 at a current density of 1 A g− 1. The specific capacitance decay rate is 29.72% when the current density is increased from 1 A g− 1 to 8 A g− 1. After 5000 cycles, the capacitance retention rate is 91.16% at a current density of 2 A g− 1, showing excellent electrochemical performance, good cycle stability and perfect energy storage performance. This research provides new experimental ideas for HCPs in the electrochemical energy storage field.
        4,600원
        51.
        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
        54.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Herein, a facile bottom–up approach for producing nitrogen-doped carbon quantum dots (N-CQDs) was carried out by the hydrothermal treatment of microcrystalline cellulose, in the presence of different nitrogen sources (blank/urea/ammonia water/ethanediamine(EDA)/Hexamethylenetetramine). The result showed that the fluorescence intensity and quantum yields (QYs) of N-CQDs with different nitrogen sources are all higher than that without nitrogen source. Compared with the other three nitrogen sources, N-CQDs prepared by EDA not only have the highest fluorescence intensity but also the largest QYs of 51.39%. Therefore, EDA was chosen as the nitrogen source to prepare N-CQDs. The obtained N-CQDs are uniform spherical particles with a diameter of 2.76 nm. The N-CQDs also exhibit excitation-dependent and long-wave emission properties. The emission range of N-CQDs is 470–540 nm. Moreover, N-CQDs as fluorescent agents successfully acted on purple LEDs (λem = 365 nm) to achieve white LEDs light emission. At the same time, a fluorescent thin layer chromatography plate was successfully prepared using N-CQDs, silica gel G and Sodium carboxymethylcellulose as raw materials. The separation trajectory of mixed sample of Sudan red III and kerosene on the fluorescent TLC plate is obviously clearer than that of the TLC plate.
        4,000원
        55.
        2022.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Porous basalt aggregate is commonly used in roadbed engineering, but its application in concrete has rarely been studied. This paper studies the application of porous basalt in concrete. Porous basalt aggregate is assessed for its effects on mechanical strength and durability of prepared C50 concrete; because it has a hole structure, porous basalt aggregate is known for its porosity, and porous basalt aggregates can be made full of water through changing the content of saturated basalt; after full-water condition is achieved in porous basalt aggregate mixture of C50 concrete, we discuss its mechanical properties and durability. The effects of C50 concrete prepared with basalt aggregate on the compressive strength, water absorption, and electric flux of concrete specimens of different ages were studied through experiments, and the effects of different replacement rates of saturated porous basalt aggregate on the properties of concrete were also studied. The results show that porous basalt aggregate can be prepared as C50 concrete. For early saturated porous basalt aggregate concrete, its compressive strength decreases with the increase of the replacement rate of saturated aggregate; this occurs up to concrete curing at 28 d, when the replacement rate of saturated basalt aggregate is greater than or equal to 40 %. The compressive strength of concrete increases with the increase of the replacement rate of saturated aggregate. The 28 d electric flux decreases with the increase of the replacement rate of saturated aggregate, indicating that saturated porous basalt aggregate can improve the chloride ion permeability resistance of concrete in later stages.
        4,000원
        56.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        공상과학소설(Science-Fiction; 이후 Sci-Fi로 표기)은 미래 세계에 대한 인간의 판타지를 표현하는 장르다. 이는 TV 쇼, 영화, 게임 분야에서 항상 뜨거운 주제였다. Sci-Fi 영화와 Sci-Fi 게임은 대부분 상위권에 오르고 있다. 하지만, 학계에서는 주로 Sci-Fi 영화에서 대한 논의에 더 집중하는 경향이 있다. 예를 들어, <Research on Color Modes of Well-known Contemporary Films(2020)>에 따르면, 최근 몇 년 동안 할리우드 Sci-Fi 영화의 주류 색상은 빨간색과 파란색에서 주황색, 노란색, 파란색, 녹색으로 바뀌었다고 분석하고 있다. 또한, Sci-Fi 영화와 관련된 질적 연구와 연구의 많은 성과가 있었다. 그러나 Sci-Fi 게임의 색조 경향에 대한 연구와 연구 는 매우 부족한 상황이다. 이에 본 논문은 Adams Roberts의 Sci-Fi 소설의 7가지 요소를 사용 한다. 이러한 7 가지 요소에 대한 Metacritic 점수가 사례 선택의 표준으로 사용되었다. 본 연구의 분석 대상으로는<HALO 3>, <Death Stranding>, <Cyberpunk 2077> 등 우수 PC게임 3종이 선정하였다. 또한, 데이터 분석은 NCS 색상 시스템을 기반으로 수행되어 Sci-Fi 게임의 색조 유사성에 대해 논의한다. 마지막으로, 우수한 게임의 색상 적 용에 대한 주요 성향을 결론짓고 요약함으로써, 본 연구는 Sci-Fi 게임의 색상 생산에 대한 몇 가지 이론적 참 조와 기초 데이터를 제공하고자 한다.
        4,000원
        57.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work using first-principles theory proposed PdN3- doped CNT ( PdN3-CNT) as a potential gas sensor for detection of NO, NO2 and O3 in the air insulated equipment, to evaluate its operation status. Results indicate that the PdN3- CNT behaves chemisorption upon three gas species, with adsorption energy (Ead) of − 2.15, − 1.91 and − 1.96 eV, and charge-transfer (QT) of − 0.141, − 0.325 and − 0.419 e, respectively. The band structure (BS) and density of state (DOS) analysis reveal that the gas adsorptions cause remarkable deformations in the electronic property of the PdN3- CNT, leading to the increase of the bandgap for the gas adsorbed systems and verifying the strong binding force of the bonded atoms from the orbital DOS. Combined with the results by frontier molecular orbital theory, we presume that PdN3- CNT is a promising sensing material to be explored as a resistance-type gas sensor for detection of NOx with higher electrical response upon NO. It is our hope that our theoretical assumption could be further studied and realized in the following experiential research, which would be meaningful to propose novel sensing candidate in the field of electrical engineering to guarantee the safe operation of the air insulation equipment.
        4,000원
        58.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the arsenide removal by using mesoporous CoFe2O4/ graphene oxide nanocomposites based on batch experiments optimized by artificial intelligence tools. These nanocomposites were prepared by immobilizing cobalt ferrite on graphene oxide and then characterized using various techniques, including small angle X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. Artificial intelligence tools associated with response surface methodology were employed to optimize the conditions of the arsenide removal process. The results showed that back propagation neural network combined with genetic algorithm was suitable for the arsenide removal from aqueous solutions by the nanocomposites based on the minimum average values of absolute errors and the value of R2. The optimal values of the four variables (operating temperature, initial pH, initial arsenide concentration, and contact time) were found to be 25.66 °C, 7.58, 10.78 mg/L and 46.41 min, and the predicted arsenide removal percentage was 84.78%. The verification experiment showed that the arsenide removal percentage was 86.62%, which was close to the predicted value. Three evaluation methods (gradient boosted regression trees, Garson method and analysis of variance) all demonstrated that the temperature was the most important explanatory variable for the arsenide removal. In addition, the arsenide removal process can be depicted with pseudo-second-order kinetics model and Langmuir isotherm, respectively. The thermodynamics investigation disclosed that the adsorption process was of a spontaneously endothermic nature. In summary, this study showed that ANN-GA was an efficient and feasible method in determining the optimum conditions for arsenic removal by CoFe2O4/ graphene oxide nanocomposites.
        4,900원
        59.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pantala flavescens is a dominant Odonata species in the rice fields in Korea. To determine the effects of different temperatures on its larval growth and emergence, field and laboratory experiments were conducted. Larval growth was also monitored in mono-cropping and double-cropping rice fields. The growth of larvae was monitored every week by measuring the head width. In the field experiment, no difference was found in larval growth and emergence between the control temperature and +1.9°C of the control temperature. The larval growth was greater at 23°C than at 20°C laboratory temperatures, and no emergence was recorded at either temperature after eight weeks of monitoring. There was a quadratic relationship between larval growth and temperature in an incubator at five temperature regimes of 15, 20, 25, 30, and 35°C. Midseason water drainage caused the extinction of the existing individuals and newly hatched larvae dominated after re-watering in the rice fields. Larval size was greater in double-cropping fields than in mono-cropping fields in late July but the tendency was reversed in early August. The results of this study suggest that temperature warming will directly promote the larval growth of P. flavescens and indirectly influence seasonal growth via changes in water management in rice fields.
        4,000원
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