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        검색결과 2,998

        81.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The current study explores the possibility of graphene as a protective layer on the zinc substrate through an optimized electrophoretic deposition process. Graphene has been synthesized from H2SO4, HNO3, and HClO4 solutions by an electrochemical exfoliation route. This method is known for providing a scalable and economical approach to the synthesis of graphene. The exfoliated graphene nano-sheets were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, UV–visible, and field emission scanning electron microscope to evaluate its properties. The three different synthesized forms of graphene nano-sheets were electrophoretically deposited onto Zn substrates at two different potentials. Scratch testing was employed to check the adhesion quality of the coatings. The corrosion behaviour of Zn and graphene-coated Zn substrates was studied in borate buffer and 3.5 wt% NaCl solutions through potentiodynamic polarization and electrochemical impedance spectroscopy. It
        5,100원
        82.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        New tetrazole fused imidazopyridine derivatives (12a–j) were developed to exploit their cytotoxic activity towards cancer cell lines-MCF7, A549, and MDA-MB-231, utilizing MTT reduction assay with doxorubicin as standard drug. The compounds 12 h and 12j demonstrated strong anticancer activity bearing IC50 values 1.44 μM and 1.33 μM against A549 cell line.
        4,000원
        83.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.
        4,000원
        84.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cat-scratch disease (CSD) is a bacterial infection which primarily transmitted to humans through scratches, bites, or licks from infected cats. Even though CSD is generally a mild condition, atypical symptoms may appear and must be distinguished from other diseases. We encountered a 57-year-old woman who presented with intermittent pain in the right upper quadrant and epigastric part of the abdomen, and had lost 11 kg within a few months. She never had a cat and did not recall being scratched by a cat. Radiologic examinations strongly suggest a malignant bile duct tumor, thus liver resection was done. However, the result of histopathology was a CSD. At follow-up, the patient was stable and also showed improvement in her general condition. Hence, proper preoperative examinations of the patients are crucial in order to avoid excessive or inadequate treatment.
        4,000원
        85.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hybrid nanocomposites of aluminium (NHAMMCs) made from AA5052 are fabricated via stir casting route by reinforcing 12 wt% Si3N4 and 0.5 wt% of graphene for usage in aeronautical and automotive applications due to the lower density and higher strength to weight proportion. The wear characteristics of the NHAMMCs are evaluated for different axial load, rotational speed, sliding distance and sliding time based on Box-Behnken design (BBD) of response surface methodology (RSM). Orowan strengthening mechanism is identified from optical image which improves the strength of the composite. Outcomes show that with higher axial load and rotational speed, there is substantial increase in wear loss whereas with increased sliding distance and sliding time there is no considerable increase in wear loss due to the lubricating nature of the reinforced graphene particles since it has higher surface area to volume ratio. Besides, artificial intelligence approach of neuro-fuzzy (ANFIS) model is developed to predict the output responses and the results are compared with the regression model predictions. Prediction from ANFIS outplays the regression model prediction.
        6,400원
        86.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cellulose has experienced a renaissance as a precursor for carbon fibers (CFs). However, cellulose possesses intrinsic challenges as precursor substrate such as typically low carbon yield. This study examines the interplay of strategies to increase the carbonization yield of (ligno-) cellulosic fibers manufactured via a coagulation process. Using Design of Experiments, this article assesses the individual and combined effects of diammonium hydrogen phosphate (DAP), lignin, and CO2 activation on the carbonization yield and properties of cellulose-based carbon fibers. Synergistic effects are identified using the response surface methodology. This paper evidences that DAP and lignin could affect cellulose pyrolysis positively in terms of carbonization yield. Nevertheless, DAP and lignin do not have an additive effect on increasing the yield. In fact, combined DAP and lignin can affect negatively the carbonization yield within a certain composition range. Further, the thermogravimetric CO2 adsorption of the respective CFs was measured, showing relatively high values (ca. 2 mmol/g) at unsaturated pressure conditions. The CFs were microporous materials with potential applications in gas separation membranes and CO2 storage systems.
        4,500원
        87.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, in order to increase the oxidation resistance of graphite, kaolin and alumina powder with different ratios (26A-74S, 49A-51S, 72A-28S) and slurry method were used to create an aluminosilicate coating on the graphite substrate. In order to reduce the difference in the coefficients of thermal expansion of graphite with aluminosilicate coating, aluminum metaphosphate coating as an interlayer was prepared on the surface of graphite by cathodic electrochemical treatment. The isothermal oxidation test of the samples was carried out in air at a temperature of 1250 °C for 1, 3 and 5 h. The microstructure, chemical composition, and phase components of the coating were, respectively, analyzed by scanning electron microscope equipped with an energy-dispersive spectrometer and X-ray diffraction. The results indicated that, by increasing the withdrawal speed of the samples in slurry method, the amount of changes in the weight of the samples has increased and therefore had a direct effect on oxidation. In addition, it was approved that, at high-temperature oxidation, AlPO4 glass phase forms on aluminum metaphosphate interlayer which retards graphite oxidation. Along with aluminum metaphosphate, aluminosilicate coating also produces a glass phase which fills and seals the voids on the surface which prevents the oxygen to reach the surface of graphite. The created double-layer coating including an interlayer of aluminum metaphosphate + slurry coating prepared with the ratio of 26A-74S as the optimal coating in this research was able to increase the oxidation resistance of graphite by 73% at a temperature of 1250 °C.
        4,600원
        88.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An environmentally friendly and low-cost chitosan-containing polysaccharide (CP) composite ZIF-8/CP was designed and prepared based on the difficulty of separating the traditional adsorbent from the water phase. ZIF-8/CP was synthesized through in-situ growth approach. The physical, chemical and structure properties of ZIF-8/CP were determined through a series of characterization methods, including SEM, FT-IR and PXRD. The effects of touch time, pH, temperature, and coexisting ions on adsorption were assessed. In addition, kinetics, isotherms of adsorption and thermodynamics were examined. The data of isotherms for adsorption indicated that the adsorption of ZIF-8/CP on MG was similar to the Langmuir model, with a maximum adsorption capacity of 1428.57 mg/g. Moreover, the kinetic parameters were consistent with the pseudo- 2nd-order equation. Thermodynamic studies (ΔG < 0, ΔH > 0) demonstrated a heat-absorbing and spontaneous adsorption process. Our study reveals that ZIF-8/CP has good adsorption properties and environmental properties.
        4,200원
        90.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The widespread and extensive use of glyphosate in agriculture has raised concerns about its potential impact on the quality and safety of agricultural products. Conventional detection methods require long analysis times, making them impractical for the rapid detection of large quantities of samples. Therefore, developing a fast and simple detection system for glyphosate pesticide residues is urgent. In this study, the development of a facile fluorescence probe synthesized using a simple one-pot hydrothermal method for the determination of glyphosate is an important step toward addressing the need for a fast and simple detection system. The present sensor was created using bovine serum albumin (BSA) as a precursor, and the sensor operates by producing an “off–on” fluorescent signal. The bovine albumin-derived BSA-CDs emitted light yellow fluorescence, but this fluorescence was quenched (or suppressed) by the presence of Cu2+ ions. However, the fluorescence can be restored by the presence of glyphosate, which interacts with the Cu2+ ions to form a complex and release the BSACDs from suppression. The functional groups in glyphosate can capture Cu2+ and break the BSA-CDs/Cu2+ combinatorial system. The BSA-CDs/Cu2+ fluorescence quenching system had good selectivity for glyphosate. The detection limit of the BSA-CD/Cu2+ fluorescence sensor was 0.05 μg/mL. This developed method was utilized to successfully detect glyphosate in Chinese wheat. The average recoveries ranged from 98.9 to 100.7%, with a relative standard deviation < 3.0%, showing good prospects for practical applicability.
        4,200원
        91.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The initial development plans for the six reactor designs, soon after the release of Generation IV International Forum (GIF) TRM in 2002, were characterized by high ambition [1]. Specifically, the sodium-cooled fast reactor (SFR) and very-high temperature reactor (VHTR) gained significant attention and were expected to reach the validation stage by the 2020s, with commercial viability projected for the 2030s. However, these projections have been unrealized because of various factors. The development of reactor designs by the GIF was supposed to be influenced by events such as the 2008 global financial crisis, 2011 Fukushima accident [2, 3], discovery of extensive shale oil reserves in the United States, and overly ambitious technological targets. Consequently, the momentum for VHTR development reduced significantly. In this context, the aims of this study were to compare and analyze the development progress of the six Gen IV reactor designs over the past 20 years, based on the GIF roadmaps published in 2002 and 2014. The primary focus was to examine the prospects for the reactor designs in relation to spent nuclear fuel burning in conjunction with small modular reactor (SMR), including molten salt reactor (MSR), which is expected to have spent nuclear fuel management potential.
        4,000원
        92.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Wolsong Nuclear Power Plant (NPP) operates an on-site spent fuel dry storage facility using concrete silo and vertical module systems. This facility must be safely maintained until the spent nuclear fuel (SNF) is transferred to an external interim or final disposal facility, aligning with national policies on spent nuclear fuel management. The concrete silo system, operational since 1992, requires an aging management review for its long-term operation and potential license renewal. This involves comparing aging management programs of different dry storage systems against the U.S. NRC’s guidelines for license renewal of spent nuclear fuel dry storage facilities and the U.S. DOE’s program for long-term storage. Based on this comparison, a specific aging management program for the silo system was developed. Furthermore, the facility’s current practices—periodic checks of surface dose rate, contamination, weld integrity, leakage, surface and groundwater, cumulative dose, and concrete structure—were evaluated for their suitability in managing the silo system’s aging. Based on this review, several improvements were proposed.
        4,200원
        93.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A transfer cask serves as the container for transporting and handling canisters loaded with spent nuclear fuels from light water reactors. This study focuses on a cylindrical transfer cask, standing at 5,300 mm with an external diameter of 2,170 mm, featuring impact limiters on the top and bottom sides. The base of the cask body has an openable/closable lid for loading canisters with storage modules. The transfer cask houses a canister containing spent nuclear fuels from lightweight reactors, serving as the confinement boundary while the cask itself lacks the confinement structure. The objective of this study was to conduct a structural analysis evaluation of the transfer cask, currently under development in Korea, ensuring its safety. This evaluation encompasses analyses of loads under normal, off-normal, and accident conditions, adhering to NUREG-2215. Structural integrity was assessed by comparing combined results for each load against stress limits. The results confirm that the transfer cask meets stress limits across normal, off-normal, and accident conditions, establishing its structural safety.
        4,600원
        94.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This article presents the crucial role played by the French underground research laboratory (URL) in initiating the deep geological repository project Cigéo. In January 2023, Andra finalized the license application for the initial construction of Cigéo. Depending on Government’s decision, the construction of Cigéo may be authorized around 2027. Cigéo is the result of a National program, launched in 1991, aiming to safely manage high-level and intermediate level long-lived radioactive wastes. This National program is based on four principles: 1) excellent science and technical knowledge, 2) safety and security as primary goals for waste management, 3) high requirements for environment protection, 4) transparent and openpublic exchanges preceding the democratic decisions and orientations by the Parliament. The research and development (R&D) activities carried out in the URL supported the design and the safety demonstration of the Cigéo project. Moreover, running the URL has provided an opportunity to gain practical experience with regard to the security of underground operations, assessment of environmental impacts, and involvement of the public in the preparation of decisions. The practices implemented have helped gradually build confidence in the Cigéo project.
        4,600원
        95.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 쑥에서 서식하는 Pleotrichophorus pseudoglandulosus (Palmer, 1952) 를 처음으로 보고한다. 무시성충에 대한 형태학적 정보, 기주식물, 분포지역, 한국에 분포하는 Pleotrichophorus 속 종들에 대한 분류키를 제공한다.
        3,000원
        96.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine the acceptability of locally accepted japonica rice varieties among 53 farmers in Bohol and 38 farmers in Nueva Ecija, who were further classified into adopters and non-adopters of the GUVA japonica rice variety. Snowball sampling was made on farmer adopters/cooperators of a high-quality seed multiplication and dissemination project in the said provinces. The farmer respondents were mostly male whose ages ranged from 30 to 80 years and with farm sizes from 0.5 to 16 hectares. The farmers’ rice variety and usage were assessed by comparing the GUVA japonica rice variety with their commonly planted indica rice variety based on its agronomic characteristics, yield and income potential, and seed purity concerns. The barriers/hesitations to adoption of the GUVA japonica rice variety, namely seed availability, varietal information, and market potential, must be complemented with the suggested improvements on the variety together with factors that convince the farmers for committed use of this variety. Researchers together with partner agencies must put a lot of thought on how to integrate and synchronize these concerns so that the farmers can adopt GUVA japonica rice. Interest check on the usage of GUVA japonica rice variety in rice production as well as suggested improvements were solicited as the basis for continuous R&D pursuits that would eventually promote and adopt the GUVA japonica rice variety from these provinces.
        4,200원
        97.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Reproductive management practices play crucial roles to maximize the reproductive performance of cows, and thus contribute to farm profitability. We aimed to assess the reproductive management of cows currently practiced in the dairy farms in an urban farming system. Methods: A total of 62 dairy farms were randomly selected considering all size of farms such as small (1-5 cattle), medium (6-20 cattle) and large farms (> 20 cattle) from selected areas of Dhaka city in Bangladesh. The reproductive managementrelated parameters viz. estrus detection, breeding method, pregnancy diagnosis, dry cow and parturition management, vaccination and treatment of reproductive problems etc. were obtained in a pre-defined questionnaire during the farm visit. Results: The visual observation method was only used (100.0%; 62/62) for estrus detection irrespective of size of the farms; while farmers observed cows for estrus 4-5 times a day, but only for 20-60 seconds each time. Regardless of farm size, 89.0% (55/62) farms used artificial insemination (AI) for breeding the cows. Intriguingly, all farms (100.0%) routinely checked the cows for pregnancy at 35-40 days post-breeding using rectal palpation technique by registered veterinarian. However, only 6.5% (4/62) farms practiced dry cow management. Notably, all farms (100.0%) provided nutritional supplements (Vit D, Ca and P) during late gestation. However, proper hygiene and cleanliness during parturition was not practiced in 77.4% (48/62) farms; even though 96.7% (60/62) farms treated cows by registered veterinarian for parturition-related problems. Conclusions: While farmers used AI service for breeding and timely check their cows for pregnancy; however, they need to increase observation time (30 minutes/ observation, twice in a day: early morning and early night) for estrus detection, consider dry cow management and ensure hygienic parturition for maximizing production.
        4,000원
        98.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The legal status of Biodiversity Beyond National Jurisdiction (BBNJ) has been regulated through the High Seas Treaty as a common heritage of humankind. However, there still exist problems related to overlapping areas above the Extended Continental Shelf (ECS). In such areas, a significant continental shelf would fall within national jurisdiction, whereas the water column would be under the regime of the high seas, and BBNJ would be the common heritage of humankind. We argue that, in order to address the overlapping of areas within the superjacent waters in the ECS, a given sui generis status is required, so that the coastal state has a sovereign right to conserve the BBNJ in these areas. This study concludes that the sui generis arrangement should be implemented in the context of an overlapping ECS and its water column. The efforts of the Indonesian government to extend the continental shelf beyond 200 nautical miles constitute an important step in preserving natural resources for future generations.
        5,200원
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