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        검색결과 3,305

        1.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        River discharge is a crucial indicator of climate change and requires accurate and continuous estimation for effective water resource management and environmental monitoring. This study used satellite gravimetry data to estimate river discharge in major basins with high discharge volumes, specifically the Congo and Orinoco basins. By enhancing the spatial resolution of gravity data through advanced post-processing techniques, including forward modeling and river routing schemes, we effectively detected changes in the water mass stored within river channels. Additionally, signals from surrounding regions were statistically removed using the Empirical Orthogonal Function (EOF) analysis to isolate river-specific discharge signals. These refined signals were then converted into river discharge data through seasonal calibration using the modeled discharge data. Our results demonstrate that this method yields accurate and reliable discharge estimates comparable to in-situ measurements from gauge stations, even without ground-based surveys such as an Acoustic Doppler Current Profiler (ADCP) field campaigns. This research highlights the significant potential of satellite-based gravity data as an alternative to traditional ground surveys, providing practical information on the hydrological status of regions associated with large-scale river systems.
        4,500원
        2.
        2024.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Kori Unit 1, the first commercial nuclear power plant (NPP) in Korea, was permanently shut down in 2017 and was scheduled for decommissioning. Various programs must be planned early in the decommissioning process to safely decommission NPPs. Radiological characterization is a key program in decommissioning and should be a high priority. Radiological characterization involves determining the decommissioning technology to be applied to a nuclear facility by identifying the radiation sources and radioactive contaminants present within the facility and assessing the extent and nature of the radioactive contaminants to be removed from the facility. This study introduces the regulatory requirements, procedures, and implementation methods for radiological characterization and proposes a methodology to link the results of radiological characterizations for each stage. To link radiological characteristics, this study proposes to conduct radiological characterization in the decommissioning phase to verify the results of radiological characterization in the transitional phase of decommissioning NPPs. This enables significantly reducing the scope and content of radiological characterization that must be performed in the decommissioning phase and maintaining the connection with the previous phase.
        4,600원
        3.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도의 Donacia속에는 2아속에 속하는 6종이 있다(An, 2019). 이 중 Chujo (1941)는 북한 함경북도 웅기에서 채집한 표본을 D. aquatica (Linnaeus, 1758)로 보고하였고, Kimoto and Kawase (1966)는 D. japana로 표기하여 보고하였다. 그리고 Hayashi (2020)는 한국에 기록된 D. japana가 D. aquatica로 오인되었을 수 있다고 밝혔다. 이러한 혼란을 해결하기 위해 본 연구는 한국(포천과 울산)에서 채집한 표본과 D. japana에 대한 기재문, 수컷생식기와 같은 형태적인 부분(Hayashi, 2020), COI 유전자 염기서열을 비교하였다. 그 결과로 한반도에 기록된 D. japana은 D. aquatica로 대체되고, D. japana는 일본 고유종이라고 결론을 내리고자 한다.
        4,000원
        4.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        장미과의 과일 및 관상용 식물은 세계적으로 경제적, 원예적 가치가 뛰어나다. 장미과의 뱀딸기는 관상 및 약용 작물로써 이용가치가 매우 높은데, 증식방법이 마련되어 있지 않은 실정 이다. 뱀딸기의 종자 종자발아 특성을 조사하기 위해 내부형태 관찰, 수분흡수실험, 온도 별 배양, move-along test, GA3처리 실험을 수행하였다. 뱀딸기 종자는 탈리시점부터 성숙한 배를 지닌다. 수분흡수실험 결과, 침지 3시간만에 종자 무게가 초 기무게 대비 100% 이상 증가하였다. 온도 별 배양 실험 결 과, 25/15, 20/10, 15/6, 5, 25, 20, 15°C에서 각각 8주간 배양하였을 때 88, 71, 61, 12, 89, 39, 17%로 나타났다. Move-along test의 T125/15°C(12주)→20/10°C(4주)→ 15/6°C(4주)→5°C(12주)]에서 12주차까지 72%가 발아하였고 T2[4°C(12주)→15/6°C(4주)→20/10°C(4주)→25/15°C(12주)] 에선 20/10°C까지 발아하지 않았고 25/15°C에 도달하고 나서 발아하여 최종발아율은 16%로 나타났다. GA3처리구에선 배양 3주차에 발아를 시작한 반면에 대조구에선 배양 4주차부터 발 아하였다. 따라서 한반도 자생 뱀딸기 종자는 PD로 분류하였다. 뱀딸기속과 Potentilla속 식물은 서로 근연관계이고, 종간의 종 자휴면에 차이가 나타나 종자휴면 특성에 분화가 일어난 것으로 판단된다.
        4,000원
        5.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is a demand for introducing a challenging and innovative R&D system to develop new technologies to generate weapon system requirements. Despite the increasing trend in annual core technology development tasks, the infrastructure expansion, including personnel in research management institutions, is relatively insufficient. This situation continuously exposes difficulties in task planning, selection, execution, and management. Therefore, there is a pressing need for strategies to initiate timely research and development and enhance budget execution efficiency through the streamlining of task agreement schedules. In this study, we propose a strategic model utilizing a flexible workforce model, considering constraints and optimizing workload distribution through resource allocation to minimize bottlenecks for efficient task agreement schedules. Comparative analysis with the existing operational environment confirms that the proposed model can handle an average of 67 more core technology development tasks within the agreement period compared to the baseline. In addition, the risk management analysis, which considered the probabilistic uncertainty of the fluctuating number of core technology research and development projects, confirmed that up to 115 core technology development can be contracted within the year under risk avoidance.
        4,000원
        6.
        2024.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Copper, silver, and gold-reduced graphene oxide nanocomposite (Cu-rGO, Ag-rGO, and Au-rGO) were fabricated via the hydrothermal method, which shows unique physiochemical properties. Environment friendly electromagnetic radiation was employed to synthesize rGO from GO. The nonlinear optical phenomenon of noble metal decorated rGO is predominantly due to excited state absorption, which arises from surface plasmon resonance and increases in defects at the surface due to Cu, Ag, and Au incorporation. It is found that the third-order nonlinear absorption coefficient was in the order of 10− 10 m/W, with notable enhancements in the third-order properties of Au-rGO compared to other nanocomposites and their respective counterparts. Functionalizing rGO induces defect states ( sp3), increasing NLO response. Cu, Ag, and Au exhibit higher Surface-Enhanced Raman Scattering (SERS) activity due to rGO-induced structural modifications. SERS signals are influenced by dominant signals from Au nanorods. The electronic structures for pure and doped rGO were investigated through Density Functional Theory (DFT). The computed partial density of states (PDOS) confirms the enhancement of the state in Au-doped rGO is due to the charge transference from Au to C 2p orbital. The optical absorption spectra and PDOS reveal the possibility of free carrier absorption enhancement in Au which validates experimentally observed higher two-photon absorption (β) value of Au-doped rGO. The tuning of nonlinear optical and SERS behaviour with variation in the noble metal upon rGO provides an easy way to attain tuneable properties which are exceedingly required in both optoelectronics and photonics applications.
        4,800원
        7.
        2024.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the key challenges for the commercialization of carbon nanotube fibers (CNTFs) is their large-scale economic production. Among CNTF spinning methods, surfactant-based wet spinning is one of the promising techniques for mass producing CNTFs. Here, we investigated how the coagulation bath composition affects the spinnability and the properties of CNTFs in surfactant-based wet spinning. We used acetone, DMAc, ethanol, and IPA as coagulants and analyzed the relationship between coagulation bath composition and the properties of CNTFs in terms of kinetic and thermodynamic coagulation parameters. From a kinetic perspective, we found that a low mass transfer rate difference (MTRD) is favorable for wet spinning. Based on this finding, we mixed the coagulant bath with solvent in a proper ratio to reduce the MTRD, which generally improved the wet spinning. We also showed that the coagulation strength, a thermodynamic parameter, should be considered. We believe that our research can contribute to establishment of surfactant-based wet spinning of CNTFs.
        4,500원
        15.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Carbon fusion is important to understand the late stages in the evolution of a massive star. Astronomically interesting energy ranges for the 12C+12C reactions have been, however, poorly constrained by experiments. Theoretical studies on stellar evolution have relied on reaction rates that are extrapolated from those measured in higher energies. In this work, we update the carbon fusion reaction rates by fitting the astrophysical S-factor data obtained from direct measurements based on the Fowler, Caughlan, & Zimmerman (1975) formula. We examine the evolution of a 20M⊙ star with the updated 12C+12C reaction rates performing simulations with the MESA (Modules for Experiments for Stellar Astrophysics) code. Between 0.5 and 1 GK, the updated reaction rates are 0.35 to 0.5 times less than the rates suggested by Caughlan & Fowler (1988). The updated rates result in the increase of core temperature by about 7% and of the neutrino cooling by about a factor of three. Moreover, the carbon-burning lifetime is reduced by a factor of 2.7. The updated carbon fusion reaction rates lead to some changes in the details of the stellar evolution model, their impact seems relatively minor compared to other uncertain physical factors like convection, overshooting, rotation, and mass-loss history. The astrophysical S-factor measurements in lower energies have large errors below the Coulomb barrier. More precise measurements in lower energies for the carbon burning would be useful to improve our study and to understand the evolution of a massive star.
        4,000원
        16.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Sarcopenia refers to a decrease in functional ability due to the loss of skeletal muscle. Sarcopenia can be prevented, delayed, and treated more effectively the sooner the intervention, and muscle mass and strength can be effectively increased through physical exercise and adequate protein intake. Because symptoms of sarcopenia do not appear in the early stages, awareness among healthcare professionals is essential for early diagnosis and subsequent intervention. Objectives: The purpose of this study was to develop sarcopenia questionnaire items and investigate additional factors in Korean clinical practice. Design: Qualitative research. Methods: A qualitative survey was conducted targeting eight physical therapists affiliated with the sarcopenia associations or physical therapists with extensive clinical experience. A preliminary sarcopenia questionnaire and a qualitative survey questionnaire created by the researchers were sent to the participants together. All questions were open-ended. Results: Through a qualitative survey, themes were derived, including barriers to equipment and healthcare reimbursement, the need for awareness of sarcopenia, and improvement of survey questions. Conclusion: The diagnosis and treatment of sarcopenia requires efforts not only from physical therapists, but also from patients, government, and professional societies.
        4,000원
        17.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Community welfare centers in Korea offer various exercise programs aimed at improving the physical and mental health of individuals with intellectual disabilities. This systematic review assesses the impact of these programs. Objectives: To systematically review and evaluate the effectiveness of exercise programs provided by community welfare centers in Korea on the physical, psychological, and mental health of children, adolescents, and adults with intellectual disabilities. Design: A systematic review. Methods: A comprehensive literature search was conducted from inception to December 1, 2023, using databases such as Korea Citation Index, Research Information Sharing Service, and Korean Medical Database. Inclusion criteria were studies focusing on individuals with intellectual disabilities engaged in exercise or exercise-based rehabilitation programs. Results: A total of 3,968 records were identified, with 14 studies meeting the inclusion criteria. Of these, 6 studies focused on children and adolescents, while 8 studies involved adults. Significant improvements were observed in physical fitness, motor performance, mobility skills, pelvic alignment, abdominal obesity, blood lipids, spontaneity, physical self-concept, adaptive behavior, and social competence for children and adolescents. For adults, notable improvements were reported in balance, physical fitness, physical activity levels, upper limb function, inflammatory markers, blood lipids, adaptive behavior, satisfaction, stress reduction, self-efficacy, emotional function, and cognitive function. Conclusion: Exercise programs provided by community welfare centers in Korea have a significant positive impact on the physical, psychological, and mental health of individuals with intellectual disabilities. These programs are essential for enhancing the quality of life for this population.
        4,000원
        18.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A phenylboric acid functionalized carbon dot (2-FPBA-CD) for rapid fluorescent sensing of glucose in blood was synthesized by simply mixing N, S-doped carbon dots (CDs) with phenylboric acid at room temperature. At pH 7.4, the response of 2-FPBA-CD to glucose could reach equilibrium in a very short time (10 min), with a wide responsive linear range of 19.70 μM to 2.54 mM, which can be applied to the detection of glucose in serum. The mechanism studies showed that the layered carbon film of 2-FPBA-CD aggregated after adding glucose, thereby leading to the fluorescence quenching of 2-FPBA-CD.
        4,300원
        19.
        2024.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this work, we investigated the photo-degradation performance of MnO2-SiC fiber-TiO2 (MnO2-SiC-TiO2) ternary nanocomposite according to visible light excitation utilizing methylene blue (MB) and methyl orange (MO) as standard dyes. The photocatalytic physicochemical characteristics of this ternary nanocomposite were described by X-ray diffraction (XRD), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), ultraviolet-visible (UV-vis), diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), photocurrent and cyclic voltammogram (CV) test. Photolysis studies of the synthesized MnO2-SiC-TiO2 composite were conducted using standard dyes of MB and MO under UV light irradiation. The experiments revealed that the MnO2-SiC-TiO2 exhibits the greatest photocatalytic dye degradation performance of around 20 % with MB, and of around 10 % with MO, respectively, within 120 min. Furthermore, MnO2-SiC-TiO2 showed good stability against photocatalytic degradation. The photocatalytic efficiency of the nanocomposite was indicated by the adequate photocatalytic reaction process. These research results show the practical application potential of SiC fibers and the performance of a photocatalyst composite that combines these fibers with metal oxides.
        4,000원
        20.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Food webs have received global attention as next-generation biomonitoring tools; however, it remains challenging because revealing trophic links between species is costly and laborious. Although a link-extrapolation method utilizing published trophic link data can address this difficulty, it has limitations when applied to construct food webs in domestic streams due to the lack of information on endemic species in global literature. Therefore, this study aimed to develop a link extrapolation-based food web model adapted to Korean stream ecosystems. We considered taxonomic similarity of predation and dominance of generalists in aquatic ecosystems, designing taxonomically higher-level matching methods: family matching for all fish (Family), endemic fish (Family-E), endemic fish playing the role of consumers (Family-EC), and resources (Family-ER). By adding the commonly used genus matching method (Genus) to these four matching methods, a total of five matching methods were used to construct 103 domestic food webs. Predictive power of both individual links and food web indices were evaluated by comparing constructed food webs with corresponding empirical food webs. Results showed that, in both evaluations, proposed methods tended to perform better than Genus in a data-poor environment. In particular, Family-E and Family-EC were the most effective matching methods. Our model addressed domestic data scarcity problems when using a link-extrapolation method. It offers opportunities to understand stream ecosystem food webs and may provide novel insights into biomonitoring.
        4,300원
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