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        검색결과 882

        2.
        2024.04 구독 인증기관·개인회원 무료
        Green pesticides, derived from natural sources, have gained wider attention as an alternative approach to synthetic pesticides in managing polyphagous pests like Spodoptera litura. In this study, the methanolic flower extract of Nyctanthes arbor-tristis (Mx-Na-t) was subjected to chemical screening, and major peak area derivatives 3-Hydroxy-1,2-dimethyl-4(1H)-pyridone (3H-dp) and Tyrosol (Ty-ol) were identified. The toxicity against S. litura larvae of Mx-Na-t (at 500 ppm) was highest in third instars (96.4%), and for 3H-dp and Ty-ol (at 5 ppm) in II instars (76.5% and 81.4%, respectively). The growth and development of S. litura larvae and pupae were significantly reduced by all three extract and phytochemical treatments. Fecundity rates also declined with the treatments, from 1,020 eggs (control) to 540 eggs (Mx-Na-t), 741 eggs (3H-dp), and 721 eggs (Ty-ol). The extract and its active constituents decreased adult emergence and slowed total larval development in a dosedependent manner. The major gut enzymes of S. litura decreased in young larvae (II instar) exposed to Mx-Na-t, 3H-dp, and Ty-ol. Fourth instar midgut tissues were severely damaged by Mx-Na-t (250 ppm), 3H-dp, and Ty-ol (2.5 ppm) treatments, which induced structural damage to the epithelial cells and gut lumen. The earthworm Eisenia foetida was used to test for non-target toxicity. Crude Mx-Na-t at 500 ppm (13% and 3%) and 3H-dp (9.3% and 2.1%) and Ty-ol (10.2% and 1.5%) at 5 ppm produced lower mortality than the synthetic chemical cypermethrin at 1.0 ppm (27% and 18%) in filter paper and artificial soil assays, respectively. In addition, there was no significant change in earthworm weights under all three phytochemical treatments compared to controls. Additionally, the in-silico predictions of BeeTox and ProTox II indicated little or no toxicity toward honey bees and other nontargets associated with 3H-dp and Ty-ol. Overall these phyto-chemicals offer an effective pest management strategy.
        3.
        2024.04 구독 인증기관·개인회원 무료
        Fas-associated death domain protein (FADD) functions as an apoptotic adapter in mammals, recruiting caspases for death-inducing signaling complexes, while in lower animals, it interacts with IMD and DREDD to initiate antimicrobial responses. In this study, we examined the T. molitor FADD sequence (TmFADD) using molecular informatics methods to understand its involvement in the host's immune response against microorganisms. Knocking down TmFADD transcripts resulted in increased susceptibility of T. molitor larvae to E. coli, underscoring the significance of FADD in insect defense mechanisms and providing valuable insights into insect immunity.
        4.
        2024.04 구독 인증기관·개인회원 무료
        Tenebrio molitor(T. molitor) is gaining attention as a sustainable food source with high nutrient content. Understanding their immune system, paricularly the role of Tak1 in the Imd pathway, is essential for mass breeding. This study investigates TmTak1 function in T. molitor. we investigated the immune function of TmTak1, followed by systemic infection using E. coli, S. aureus, and C. albicans. As a result, Silencing TmTak1 significantly affects expression levels of AMPs in the whole body, Fat bodies, and Integuments. These results showed lower expression levels of AMP compared to the control group during E.coli injection.
        6.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The forward head posture acts as a factor that can cause various neurovascular and musculoskeletal dysfunctions. But searching for a study on quality of life for patient with forward head posture was challenging. Therefore, this study aims to find the factors that most affect the quality of life in patients with forward head posture. Objectives: The purpose of this study was to investigate the correlations between the cranio-vertebral angle (CVA), neck disability index (NDI), pain, and sternocleidomastoid (SCM) thickness of patients with forward head posture and the quality of life of the patients and to figure out important factors that affect the quality of life of the patients with forward head posture. Design: Cress-sectional study. Methods: To measure the CVA, the angle at which the visible protrusion of C7 and the ear bead were connected was measured, and the neck disorder index was evaluated using the Korean version of NDI. The degree of pain of the subject was measured using a visual-analog scale (VAS). The SCM thickness was measured using an ultrasound imaging device, and the quality of life was evaluated using the Korean version of the World Health Organization quality of life questionnaire (WHOQL-BREF). Results: A significant predictive model showing 88% explanatory power for the dependent variable was confirmed, with an appropriate regression equation being found. The factor that most affected patients' quality of life in the forward head posture was confirmed by the SCM thickness. Conclusion: When applying an intervention to improve a patient's quality of life for patient with forward head posture, an intervention method that improves the SCM thickness should be recommended.
        4,000원
        7.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explores the profound impact of varying oxygen content on microstructural and mechanical properties in specimens HO and LO. The higher oxygen concentration in specimen HO is found to significantly influence alpha lath sizes, resulting in a size of 0.5-1 μm, contrasting with the 1-1.5 μm size observed in specimen LO. Pore fraction, governed by oxygen concentration, is high in specimen HO, registering a value of 0.11%, whereas specimen LO exhibits a lower pore fraction (0.02%). Varied pore types in each specimen further underscore the role of oxygen concentration in shaping microstructural morphology. Despite these microstructural variations, the average hardness remains consistent at ~370 HV. This study emphasizes the pivotal role of oxygen content in influencing microstructural features, contributing to a comprehensive understanding of the intricate interplay between elemental composition and material properties.
        4,000원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we synthesized a reduced graphene oxide-manganese dioxide (rGO-MnO2) composite material using a one-step hydrothermal method and used it as a transducer layer in solid-state ion-selective electrodes (ISEs) for monitoring potassium and sodium ions in sweat. The rGO-MnO2 composite was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), revealing its unique surface morphology and crystalline structures. Electrochemical characterizations, including cyclic voltammetry (CV) and potential response testing, demonstrated the excellent performance of the rGO-MnO2 composite material as a transducer layer in ISEs. The fabricated electrodes displayed good linear responses to potassium and sodium ions, with a voltage response of 36.4 mV and 47.6 mV per unit concentration change, respectively. The electrodes also exhibited improved resistance to gas interference, such as O2, N2, and CO2. We utilized these ISEs to measure changes in potassium and sodium ion concentrations in sweat samples collected over nine days of exercise, demonstrating the practical application of the rGO-MnO2-based ISEs. This work highlights the potential of using graphene/metal oxide composites as solid contact materials in ISEs for cost-effective and stable ion sensing applications.
        4,000원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수국은 수국과(Hydrangeaceae) 수국속(Hydrangea)의 낙엽관목 식물로 크고 화려한 화형을 가져 절화, 분화 및 조 경수로 전세계적 인기가 있는 식물이다. 나무수국은 수국 (H. macrophylla)과 비교하여 삽목율이 낮은 것으로 알려져 있지만 나무수국의 묘목생산을 위한 삽목 연구 및 두 종간 삽목율 차이 원인 규명에 관한 연구는 미미하다. 본 연구는 IBA(Indol-3-butyric acid) 500mg·L-1 처리시 삽수의 침지 시간에 따른 삽목율 조사를 통해 적정 호르몬 처리 시간을 제 시하고 나무수국과 수국의 해부학적 구조 관찰을 통한 삽목율 차이 발생의 원인을 규명하고자 실시하였다. 나무수국의 적정 호르몬 처리 시간을 규명하기 위해 IBA 500mg·L-1을 무처 리, 30분, 2시간, 4시간 침지처리를 하였다. 종간 삽목율 차이 발생의 원인 규명을 위해 나무수국과 수국의 줄기 단면과 삽 목 후 시간 경과에 따른 발근을 해부학적으로 관찰하였다. 연 구의 결과 나무수국의 삽목시 IBA 500mg·L-1에 2시간 이상 침지처리가 다른 처리구와 비교하여 발근율이 높고 발생 뿌리 수가 가장 많았다. 또, 나무수국의 삽목율이 수국과 비교하여 낮은 것은 줄기의 세포 구조상 방사조직의 형태, 섬유세포의 밀도, 도관의 발달, 전분 함유 세포의 수 등에 차이가 관찰되 었고 이러한 세포 구조적 차이들의 영향으로 나무수국이 수국 보다 삽목 후 뿌리 조직 세포분열이 7일 늦게 시작되는 것이 확인되었다. 본 연구의 결과로 나무수국의 삽목 번식의 기초 자료로 활용되어 묘목 생산 효율 증대에 활용되길 바란다.
        4,000원
        10.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Emojis and avatars are widely used in online communications, but their emotional conveyance lacks research. This study aims to contribute to the field of emotional expression in computer-mediated communication (CMC) by exploring the effectiveness of emotion recognition, the intensity of perceived emotions, and the perceived preferences for emojis and avatars as emotional expression tools. The following were used as stimuli: 12 photographs from the Yonsei-Face database, 12 Memojis that reflected the photographs, and 6 iOS emojis. The results of this study indicate that emojis outperformed other forms of emotional expression in terms of conveying emotions, intensity, and preference. Indeed, the study findings confirm that emojis remain the dominant form of emotional signals in CMC. In contrast, the study revealed that Memojis were inadequate as an expressive emotional cue. Participants did not perceive Memojis to effectively convey emotions compared with other forms of expression, such as emojis or real human faces. This suggests room for improvement in the design and implementation of Memojis to enhance their effectiveness in accurately conveying intended emotions. Addressing the limitations of Memojis and exploring ways to optimize their emotional expressiveness necessitate further research and development in avatar design.
        4,000원
        12.
        2023.11 구독 인증기관·개인회원 무료
        High-temperature molten salts not only demonstrate exceptional thermal and chemical stability but also offer significant advantages in catalyzing chemical reactions. Consequently, they have garnered attention as a promising medium for next-generation nuclear reactors and a wide range of electrochemical processes. Nevertheless, the challenging experimental conditions in molten salts make applying conventional analytical methods to understand reaction mechanisms a formidable task. This underscores the imperative need for more intuitive approaches to investigate molten salt chemistry. One of the simplest yet potent methods involves real-time visual monitoring of the reaction system as chemical reactions progress. In light of this, we have developed an experimental system enabling real-time visual monitoring of the internal dynamics of molten salt media. This system can capture high-resolution videos and images within molten salts, surpassing existing methodologies. We have applied this system in various electrochemical experiments using the molten LiCl-KCl eutectic salt medium. Among them, this study primarily focuses on two challenging experimental scenarios that became comprehensible through our proposed system’s application: (1) the transpassivation of Zr metal and the agglomeration of potassium hexachlorozirconate (K2ZrCl6) solid salt, and (2) the solvation of electrons during the oxidation of Li metal within the molten LiCl-KCl eutectic salt.
        13.
        2023.11 구독 인증기관·개인회원 무료
        Korea Atomic Energy Research Institute (“KAERI”) has been developing pyroprocess technology for the sustainable use of nuclear energy and radioactive waste reduction, and is conducting design studies for a Pyroprocess Commercializing Research Facility (PCRF). High-level radioactive materials such as spent nuclear fuel, which are handled in the hot cell of the PCRF, physically change materials directly or cause chemical changes through ionization or excitation depending on the energy and types of radiation. Therefore, all facilities, including process equipment and remote handling equipment, installed into the hot cell must be evaluated for radiation hardness to be maintained in the radiological environmfent so that processes can proceed throughout the design life of the facility. In addition, as the maintenance paradigm has recently shifted from corrective maintenance to predictive maintenance, it is necessary to know in advance the condition of the equipment or facility in the radiological environment. In this study, an analysis of the radiation environment of the hot cell in the PCRF was conducted through source term, and the radiological dose impact was evaluated through the results of irradiation experiments of major components by reference data. Then, the actual dose contribution was identified through dose assessment using the MCNP code based on the pyroprocess equipment, and the radiation hardness requirements for the facility and equipment in the hot cell were derived by the above results.
        14.
        2023.11 구독 인증기관·개인회원 무료
        In the dismantling of nuclear power plants, various forms of radioactive gaseous waste are generated when cutting concrete and metal structures. Large amounts of radioactive dust and aerosols generated during the cutting process of each structure can cause radiation exposure to the environment around the workplace and to the radiation exposure in the body of workers. When cutting structures, water is sprayed to reduce the generation of aerosols, so early saturation of the filter is expected due to radioactive aerosols and fine particles containing a large amount of moisture. A mobile air purification device is being developed to a fast and efficient air purifier that can be used for a long time operation to protect workers from radiation exposure in high radiation areas and to minimize the amount of secondary waste generated. In this paper, the direction for a new concept of unit technology that can achieve the development purpose is described.
        15.
        2023.11 구독 인증기관·개인회원 무료
        Currently, Korea is planning to use various equipments and technologies for cutting, decontamination, compression, solidification, and packaging at decommissioning site of Kori unit 1 and Wolsung unit 1. In particular, Korea is considering to apply new technologies like inorganic acid decontamination, spent resion treatment technology not only to localize various decommissioning technology, but to meet the limit of 14,500 drums of the decommissioning waste per unit. However, before the techniques applied to decommissioning, it is necessary to demonstrate the effectiveness and the safety of the techniques. Because unlike the industrial fields, the failure of the decommissioning technique in nuclear power plants can cause the spread or leakage of radioactive materials. In the「Regulation on Technical Standards for Nuclear Reactor Facilities, Etc.」is stated that the licensee shall apply proven technology to decommissioning and if the licensee apply new technology, he must provide resonable evidence and prove its safety. In accordance with this approach, Nuclear Safety and Security Commission (NSSC) Notice No. 2021-24 can be applied to the decommissioning technology as one of a technical standard related with the demonstration of it. And it states 9 kinds of elements related to the radioactive waste management facilites and components like the management of radioactive effluents, prevention of contamination and overflow by radioactive materials, etc. But, they are mixed with the radioactive material considerations and industrial considerations, and these considerations are usually for the facilities, not equipments or techniques. On the other hand, in the IAEA Safety Standards Series No. WS-G-2.1 Section 6.15 to 6.20, it recommended to evaluate 12 considerations for the decontamination technique and 7 considerations for the dismantling techniques. The Decommissioning Guide in Germany recommends to consider 3 conditions for radiation protection of decontamination techniques and 4 conditions for dismantling techniques. Therefore, it is necessary to compare the safety requirements or recommendations related to the demonstration of decommissioning technology with the other countries to check there is something to learn from it.
        16.
        2023.11 구독 인증기관·개인회원 무료
        Decontamination is one of the important processes for dismantling nuclear power plants. The purpose of decontamination is to reduce the radiation levels of contaminated nuclear facilities, ensuring the safety of workers involved in decommissioning and minimizing the amount of radioactive waste. In this study, we investigate the reaction mechanisms and their thermodynamic energies of the HyBRID (Hydrazine-Based Reductive participated metal Ion Decontamination) process for decontamination of the primary coolant system of a nuclear power plant. We computed the thermodynamic properties of HyBRID dissolution mechanisms in which corrosion metal oxides accumulated in the primary coolant systems along with radionuclides are dissolved by HyBRID decontamination agents (H2SO4/N2H4/CuSO4). The HyBRID reaction mechanism has been studied using a commercial database (HSC Chemistry®), but Cu ions have been used instead of Cu-hydrazine complexes when calculating reactions due to the absence of thermodynamic properties for Cu-hydrazine complexes. To address this limitation, we supplemented the quantum calculations with Cu-hydrazine complexes using the density functional calculations. It is intended to simulate a more practical reactions by calculating the reactions considering Cu-hydrazine complexes, and to improve understanding of the HyBRID dissolution reactions by qualitatively and quantitatively comparing the reactions without considering the complex formation.
        17.
        2023.11 구독 인증기관·개인회원 무료
        There is a large amount of radioactive waste in waste storage in the Korea Atomic Energy Research Institute. Some of the radioactive waste was generated during the dismantling process due to Korea Research Reactor 1&2 and it accounts for 20% of the total waste. Radioactive waste must be reduced by appropriate disposal methods to secure storage space and to reduce disposal costs. Research Reactor wastes include wastes that are below the acceptable criteria for selfdisposal and non-contaminated wastes, so they can be treated as wastes subject to self-disposal through contamination analysis and reclassification. In order to deregulation radioactive waste, it is necessary to meet the self-disposal standards stipulated in the Domestic Nuclear Act and the treatment standards of the Waste Management Act. The main factors of deregulation are surface contaminant, radionuclide activity and dose assessment. To confirm the contamination of waste, surface contaminant and gamma nuclide analysis were performed. After homogenizing the waste sample, it was placed in 1 L Mariinelli beaker. When collecting waste samples, 1 kg per 200 kg of waste was collected. The concentrations of the major radionuclides Co-60, Cs-134, Cs-137, Eu-152, and Eu-154 were analyzed using HPGe detector. To evaluate radiation dose, various computational programs were used. A dose assessment was performed with the analyzed nuclide concentration. The concentrations of representative nuclides satisfied the deregulation acceptance criteria and the results of the dose assessment corresponding to self-disposal method was also satisfied. Based on this results, KAERI submitted the report on waste self-disposal plan to obtain approval. After final approval, Research Reactor waste is to be incinerated and incineration ash is to be buried in the designated place. Some metallic waste has been recycled. In this study, the suitability of deregulation for self-disposal was confirmed through the evaluation of the surface contaminant analysis, radionuclide concentration analysis and dose assessment.
        18.
        2023.11 구독 인증기관·개인회원 무료
        As part of the preparation of a glossary of terminologies related to the disposal of spent nuclear fuel, definitions of potentially issuable terminologies used in domestic regulations were inferred from relevant regulations or comparatively analyzed with foreign definitions. These terminologies are safety assessment and performance assessment, safety function and safety performance, disposal containers and package, isolation and containment, and so on. Their concise and easy-to-understand definitions have been proposed in order to obtain these opinions of stakeholders.
        19.
        2023.11 구독 인증기관·개인회원 무료
        This paper describes the development and operation of an autonomous robotic system designed for pyroprocess automation. The unique challenges of pyroprocess automation, such as the need for a highly dry atmosphere to handle materials like chloride, are addressed through this system. For the experiments, a specialized dehumidifier and dry mock-up facility were designed to produce dry air condition. Performances of dry air conditioning for the various simulated situations were evaluated, including assessing worker access within a mock-up to determine the system’s feasibility. To enable automation, containers used for processing materials were modified to fit the gripper system of the gantry robot. The loading and unloading of materials in each equipment were automated to connect them with the robotic system. This gantry robot primarily utilized macro motions to approach waypoints containing process materials, reducing the need for precise approach motions. Its tapered jaw design allowed it to grip target objects even with imperfect positioning. The robot’s motions were programmed initially using a robot simulator for positioning and motion planning, and real-world accuracy was tested in a dry mock-up facility using the OPC platform. Finally, the paper discusses the potential application of XR (eXtended Reality) technology in this context, which could enhance the robot’s operation and provide valuable insights into the automation process. Further analysis of XR technology’s feasibility and benefits for this specific pyroprocess automation system are presented.
        20.
        2023.11 구독 인증기관·개인회원 무료
        As part of strengthening pyro safety measures, the Korea Atomic Energy Research Institute is developing LIBS (Laser-Induced Breakdown Spectroscopy) application technology to analyze molten salt components in electrolytic recovery device in real time. LIBS performs qualitative and quantitative analysis by analyzing the spectrum of energy emitted by atomizing and ionizing elements on the surface of a salt sample with a high-focused laser. Since salt easily corrodes metal, it must be managed in an environment with a dew point of -40°C or lower. In this study, we designed and manufactured a device that places a rod-type sampling stick on a mounting base, automatically moves it to the optimal measurement position for LIBS, and retrieves the sample. Its characteristics are as follows. First, LIBS is stationary and does not move. Second, the sample stick is placed on a mounting base and can rotate 360 degrees. Third, according to the command, the sample stick automatically moves to the optimal measurement position of LIBS with three degrees of freedom (X, Y, Z). Fourth, the salt attached to the sampling stick is recovered for chemical analysis by driving the gripper mounted at the bottom of the Z axis, Z axis, and rotation axis (R). The X, Y, and Z movement distances of this device are each 100 mm, rotation is 360 degrees, grip stroke is 50 mm, and position accuracy is ±20 m. Once the performance test of the automated salt sample analysis device is completed, it will be installed in a dry room with a dew point of - 40°C or lower. Samples will be collected remotely in connection with the electrolytic recovery device and gantry robot built in the dry room. We plan to conduct experiments to seat the sample stick. Ultimately, we plan to conduct comprehensive experiments in conjunction with LIBS.
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