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        검색결과 648

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Largemouth bass (Micropterus salmoides) is introduced species that has caused aquatic ecology activity both in vitro and in vivo were investigated for the possibility of application of the bass extract as an alternative feed ingredient. Methods: The bass oil was extracted using a 1-L supercritical extractor, while the protein was extracted from 250 g of bass dry matter, which was dissolved in 1 mL of H2O at 50℃. Both oil and protein extracts were evaluated antioxidant activities and the level of DPPH radical scavenging assay and nitric oxide (NO) production assay with lipopolysaccharide response. Oral administration of 6.6 μL/g bass protein and 5.38 μL/g bass oil conducted for investigating serological and physiological effect. Results: DPPH radical scavenging showed similar radical scavenging ability of 50 μM of ascorbic acid at 200 μg of protein and 10% of oil treatment. NO concentration was diminished by the treatment of bass oil. Oral administration of both bass oil and proteins to mice showed that the body weight increase rate of the bass oil treated group was significantly reduced by 1.55 g compared to the other groups. The number of white blood cells (WBC) was increased by 4.52 k/μL in the bass protein-treated group and 4.44 k/μL in the bass oil-treated group compared to the control group. However, the serum IgG level did not show a significant difference between the bass extract-treated groups and the control group. Conclusions: These studies demonstrate that both bass oil and proteins extracted from the bass not only provide excellent effects of antioxidant and immune activity but can also be used as functional food supplements.
        4,200원
        2.
        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
        5.
        2023.11 구독 인증기관·개인회원 무료
        To achieve permanent disposal of radioactive waste drums, the radionuclides analysis process is essential. A variety of waste types are generated through the operation of nuclear facilities, with dry active waste (DAW) being the most abundant. To perform radionuclides analysis, sample pretreatment technology is required to transform solid samples into solutions. In this study, we developed a dry ashing-microwave digestion method and secured the reliability of the analysis results through a validity evaluation. Additionally, we conducted a comparative analysis of the radioactivity of 94Nb nuclides with and without the chemical separation process, which reduced the minimum detectable activity (MDA) level by more than 65-fold for a certain sample.
        6.
        2023.11 구독 인증기관·개인회원 무료
        The nuclear fuel that melted during the Fukushima nuclear accident in 2011 is still being cooled by water. In this process, contaminated water containing radioactive substances such as cesium and strontium is generated. The total amount of radioactive pollutants released by the natural environment due to the nuclear accident in Fukushima in 2011 is estimated to be 900 PBq, of which 10 to 37 PBq for cesium. Radioactive cesium (137Cs) is a potassium analog that exists in the water in the form of cations with similar daytime behavior and a small hydration radius and is recognized as a radioactive nuclide that has the greatest impact on the environment due to its long half-life (about 30 years), high solubility and diffusion coefficient, and gamma-ray emission. In this study, alginate beads were designed using Prussian blue, known as a material that selectively adsorbs cesium for removal and detection of cesium. To confirm the adsorption performance of the produced Prussian blue, immersion experiments were conducted using Cs standard solution, and MCNP simulations were performed by modeling 1L reservoir to conduct experiments using radioactive Cs in the future. An adsorption experiment was conducted with water containing standard cesium solution using alginate beads impregnated with Prussian blue. The adsorption experiment tested how much cesium of the same concentration was adsorbed over time. As a result, it was found that Prussian blue beads removed about 80% of cesium within 10-15 minutes. In addition, MCNP simulation was performed using a 1 L reservoir and a 3inch NaI detector to optimize the amount of Prussian blue. The results of comparing the efficiency according to the Prussian volume was shown. It showed that our designed system holds great promise for the cleanup and detection of radioactive cesium contaminated seawater around nuclear plants and/or after nuclear accidents. Thus, this work is expected to provide insights into the fundamental MCNP simulation based optimization of Prussian blue for cesium removal and this work based MCNP simulation will pave the way for various practical applications.
        7.
        2023.11 구독 인증기관·개인회원 무료
        There are analytical methods used for measuring activity when light photons are emitted for scintillating-based analytical application. When this electron returns to the original stable state, it releases its energy in the form of light emission (visible light or ultraviolet light), and this phenomenon is called scintillation. Scintillator is a general term for substances that emit fluorescence when exposed to radiation such as gamma-rays. Radioactivity is all around us and is unavoidable because of the ubiquitous existence of background radiations emitted by different sources. The scintillator contributes to these sensing, and it is expected that the inspection accuracy and limit of detection will be improved and new inspection methods will be developed in the future. Moreover, scintillators are chemical or nanomaterial sensors that can be used to detect the presence of chemical species and elements or monitor physical parameters on the nanoscale. In this study, it includes finding use in scintillating-based analytical sensing applications. A chemical and nanomaterial based sensors are self-contained analytical tools that could provide information about the chemical compositions or elements of their environment, that is, a liquid or even gas condition. Herein, we present an insightful review of previously reported research in the development of high-performance gamma scintillators. The major performance-limiting factors of scintillation are summed up here. Moreover, the 2D material has been discussed in the context of these parameters. It will help in designing a prototype nanomaterial based scintillators for radiation detection of gamma-ray.
        8.
        2023.11 구독 인증기관·개인회원 무료
        Radioactive contamination distribution in nuclear facilities is typically measured and analyzed using radiation sensors. Since generally used detection sensors have relatively high efficiency, it is difficult to apply them to a high radiation field. Therefore, shielding/collimators and small size detectors are typically used. Nevertheless, problems of pulse accumulation and dead time still remain. This can cause measurement errors and distort the energy spectrum. In this study, this problem was confirmed through experiments, and signal pile-up and dead time correction studies were performed. A detection system combining a GAGG sensor and SiPM with a size of 10 mm × 10 mm × 10 mm was used, and GAGG radiation characteristics were evaluated for each radiation dose (0.001~57 mSv/h). As a result, efficiency increased as the dose increased, but the energy spectrum tended to shift to the left. At a radiation dose intensity of 400 Ci (14.8 TBq), a collimator was additionally installed, but efficiency decreased and the spectrum was distorted. It was analyzed that signal loss occurred when more than 1 million particles were incident on the detector. In this high-radioactivity area, quantitative analysis is likely to be difficult due to spectral distortion, and this needs to be supplemented through a correction algorithm. In recent research cases, the development of correction algorithms using MCNP and AI is being actively carried out around the world, and more than 98% of the signals have been corrected and the spectrum has been restored. Nevertheless, the artificial intelligence (AI) results were based on only 2-3 overlapping pulse data and did not consider the effect of noise, so they did not solve realistic problems. Additional research is needed. In the future, we plan to conduct signal correction research using ≈10×10 mm small size detectors (GAGG, CZT etc.). Also, the performance evaluation of the measurement/analysis system is intended to be performed in an environment similar to the high radiation field of an actual nuclear facility.
        9.
        2023.11 구독 인증기관·개인회원 무료
        Radioactive liquid waste generated during the operation of domestic nuclear power plants is treated through a somewhat different liquid radwaste system (LRS) for each plant. Prior to the introduction of standard nuclear power plants, LRS used a concentrated water dry system (CWDS) to evaporate liquid waste and manage it in the form of dry powder. The boron-containing radioactive liquid waste dry powder was solidified using paraffin from 1995 to 2010, and about 3,650 drums (based on 200 L) of paraffin solidified drums are currently stored in nuclear power plants. Paraffin solidification drums do not meet the acceptance criteria for radioactive waste repositories because it is difficult to secure the homogeneity of the solidified body and there are concerns about leaching of radioactive waste due to the low melting point of paraffin. In order to solve this problem and safely permanently dispose of paraffin solidification drums, the characteristics of dry powder paraffin solidification drums containing boron-containing radioactive liquid waste must be analyzed and appropriate treatment technology utilizing the results must be introduced. This study analyzes the physical properties of paraffin, the chemical properties of boron-containing radioactive waste dry powder, and the physicochemical properties of paraffin solidification powder, and proposes an appropriate alternative technology for treating boron-containing radioactive waste dry drum. When disposing of the paraffin solidification drum with boron-containing radioactive liquid waste dry powder, the solidification body must be effectively withdrawn from the drum and the paraffin must be completely separated from the solidification body. When disposing the drum, the solidified material must be effectively extracted from the drum and the paraffin must be completely separated from the solidified material. Afterwards, the paraffin must be self-disposed, and the radioactive waste must be disposed of in accordance with acceptance criteria of repository. We looked at how each characteristic of the paraffin solidification drum with boron-containing radioactive liquid waste dry powder can be utilized in each of the above treatment processes.
        10.
        2023.10 구독 인증기관·개인회원 무료
        멸강나방은 중국 내 개체군이 북쪽 지역으로 2차 이주를 할 때, 봄철 제트기류를 타고 국내로 유입되는 비래해 충이다. 집단으로 발생 시 벼, 옥수수, 수수 등 여러 작물에 큰 피해를 준다. 2020년과 2021년 북방접경 세 지역(백령 도, 연천, 고성)과 수원 지역에서 성페로몬트랩을 이용하여 멸강나방의 성충 발생 시기를 탐지하였다. 일반적으 로 수원지역은 4월 하순 혹은 5월 상순에 최초 유인되었으나 두 해 여러 지역에서 공통적으로 탐지되는 시기는 6월 초중순이었다. 미국 해양대기청(NOAA)에서 제공하는 역궤적 분석프로그램(HYSPLIT)을 이용하여 각 지 역에서 멸강나방이 포획된 날짜 별 지상 300, 500, 700, 1000 m의 36~72시간 역궤적 분석을 수행하였다. 이후 같은 시기에 중국 내 멸강나방이 분포할 가능성이 높은 지역(32~40 ºN)을 비래 근원지로 추정하였다. 2021년 수원과 백령도에서 공통적으로 산둥성(山东省)이 근원지로 추정되었다. 공통적으로 산둥성(山东省)과 장수성(江苏 省)이 주 비래지로 추정되었고, 추가적으로 백령도는 허베이성(河北省), 수원은 안후이성(安徽省), 허베이성(河 北省), 저장성(浙江省)도 가능성이 있는 지역으로 추정되었다.
        11.
        2023.10 구독 인증기관·개인회원 무료
        화분매개의존도는 밀원가치를 평가하는데 매우 필요한 자료임에도 불구하고, 산림 자원에 대한 화분매개의 존도 자료는 매우 부족하다 본 연구는 국내 중부지방에 분포하는 밀원수를 대상으로 화분매개의존도, 화밀/화분 생산량 및 꽃의 형태학적 특징을 규명을 목적으로 하였다. 화분매개의존도는 개화 전 꽃봉오리를 망사를 씌워 화분매개자의 출입을 제한 후, 결실률을 조사하여 평가했다. 화밀은 모세관 튜브를 이용하여 조사하며, 화분은 꽃가루의 수와 무게 측정을 통해 생산량을 추정하였다. 식물의 특징으로는 각 식물의 본 당 꽃 수, 개화시기, 화관 및 화서의 형태 등 형태적 특징을 조사하였다. 65종 평균 화분매개자 의존도는 평균 56±3.12%로 나타났고, 최대 100%(산수유), 최소 0%(상수리)로 나타났다. 45종의 화밀 및 화분량을 추정한 결과, 꽃 당 평균 화밀의 분비량은 인동 3.56±0.33㎕으로 가장 높았으나, 본 당 평균 화밀 분비량은 피나무 212.7㎖로 가장 높았다. 평균 화분의 무게는 피나무가 141.75g로 가장 많았다. 꽃 당 화밀량은 밀원수의 개화하는 시기가 봄에서 여름이 가까워질수록 적어졌 으나, 7, 8월에는 본 당 꽃의 수가 증가하여 여름에 개화하는 식물들이 본 당 화밀의 양을 더 많이 분비하는 경향을 확인하였다. 이는 산림 생태계의 밀원가치를 평가하는데 기초적인 자료로 활용될 수 있을 것으로 판단된다.
        15.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated unrecorded freshwater bacterial species in Korea. Water and sediment samples were collected from the Nakdong River basin from 2020-2022. Bacterial isolates obtained through the conventional culture method with commercial media were subjected to 16S rRNA gene sequencing to identify unrecorded bacterial species. Results of 16S rRNA gene sequencing of the bacterial isolates revealed that a total of 44 bacterial isolates shared 16S rRNA gene sequence similarities of more than 98.65%, with validly published bacterial species not reported in Korea yet. These isolates were phylogenetically assigned to 4 phyla, 7 classes, 21 orders, 33 families, and 42 genera. A total of 2, 6, 12, and 24 species belonged to phyla Bacillota, Bacteroidota, Actinomycetota, and Pseudomonadota, respectively. Here, we provide details of these 44 unrecorded bacterial species, including Gram staining, colony and cellular morphologies, biochemical properties, and phylogenetic position.
        5,100원
        16.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Buckwheat (Fagopyrum esculentum), which is a traditional Korean crop, has been known as a health food due to its rich nutrition. This study was conducted to evaluate the change in flavonoid content of flowers and seeds during post-flowering growth of Korean tartary buckwheat variety ‘Hwanggeummiso’, with the aim of providing basic data for the development of functional food and feed additive. Tartary buckwheat took 69 and 99 days from the sowing date to reach the flowering and maturity stages, respectively. As a result of examining the flavonoid components of each part of tartary buckwheat, chlorogenic acid, rutin, and isoquercitrin of flowers increased from the flowering period on 22 May (0 days after flowering) to 42 days after flowering, while quercetin increased until 21 days after flowering and then decreased thereafter. In seeds, chlorogenic acid, rutin, and isoquercitrin were most abundant at the time of seed-bearing on 14 days after flowering, and showed a decreasing tendency thereafter. On the other hand, quercetin showed a tendency to increase until 21 days after flowering and then decrease. Overall, the flavonoid content was higher in flowers than in seeds, with rutin being particularly prominent. Based on this, the possibility as food materials and feed additives was confirmed using buckwheat produced in Korea.
        4,000원
        17.
        2023.07 구독 인증기관 무료, 개인회원 유료
        Instagram marketing is a popular tool for communication in the tourism industry. However, research into effective execution tactics has been limited to the content, recipient characteristics, and sender types (e.g., celebrities) (i.e., Ferwerda & Tkalcic, 2018; Jin et al., 2019; Singh, 2020). The layouts of Instagram ads themselves have received little scholarly attention. Instagram ads typically convey multiple pieces of information in a single advertisement unit, raising concerns about the significance of the order in which the information is presented. Specifically, we must understand how different orders of presenting information affect a firm’s performance. Therefore, this study investigates the effect of presentation order on consumer behavioral intentions toward tour programs promoted on Instagram.
        4,000원
        18.
        2023.07 구독 인증기관 무료, 개인회원 유료
        Drawing from the uses and gratification theory (UGT), the study intends to investigate audiences’ motivation to watch Livestream and its influence on subscription and donation. The roles of viewers’ parasocial relationships and identification with live streamers were also examined. The results also indicate the presence of a mediation effect.
        4,000원
        19.
        2023.05 구독 인증기관·개인회원 무료
        The decommissioning of the Nuclear Power Plant (NPP) is a long-term project of more than 15 years and will be carried out as a project, which will require project management skills accordingly. The risk of decommissioning project is a combination of many factors such as the decommissioning plan, the matters licensed by the regulatory agency, the design and implementation of dismantling, the dismantling plan and organization, and stakeholders. There will be some difficulties in risk management because key assumptions about many factors and the contents of major risks should be well considered. Risk management typically performs a series of processes ranging from identification and analysis to evaluation. In order to analyze and evaluate risks here, identification of potential risks is the first step, and in order to reasonably select potential risks, various factors mentioned should be considered. Therefore, the purpose of this study is to identify possible risks that should be considered for the decommissioning project in various aspects. The risk of the decommissioning project can be defined using the hazard keyword, and the risk family presented in the IAEA safety series can also be referred. It would be better to approach the radiological or non-radiological risks that may occur in the dismantling work with the hazard keyword, and if the characteristics of the decommissioning project are reflected, it would be a good idea to approach it on a risk family basis. There are 10 top risks in the risk family, 25 risks at the level 2 and 61 risks at the level 3 are presented. It may be complex to consider these hazards and risks recommended as risk families at the same time, so using the results of safety evaluation as input data for risk identification can be a reasonable approach. Therefore, this study intended to derive the possible risks of the decommissioning project based on the risk family structure. At this point, the reflection of the safety assessment results was intended to be materialized by considering the hazards checklist. As a result, this study defined and example of 38 possible risks for the decommissioning project, considering the 10 top risk family and lower level risk categories. This result is not finalized, and it will be necessary to further strengthened through expert workshops or HAZOP in the future.
        20.
        2023.05 구독 인증기관·개인회원 무료
        Laser cutting technology capable of remote cutting is being developed to reduce radiation exposure to workers and minimize secondary waste generation when dismantling highly polluted nuclear power plant facilities (reactors, pressurizers, steam generators, coolant pumps, etc.). Laser cutting proceeds in air or water, and at this time, secondary products containing radioactive materials are inevitably generated. In air cutting, dust and aerosol are generated, and in underwater cutting, aerosol, water vapor, dispersed particles (colloid, suspension), sediment (dross, sediment), and radioactive waste liquid are generated. Dispersed particles float in the form of fine particles in water, increasing the turbidity of water as cutting progresses, hindering work, and aerosols contain micrometer-sized particles together with water vapor, which can threaten the safety of workers. Particles dispersed in water and aerosol are within 10% of the mass ratio among secondary products, but the volume they occupy is very large, which can have a significant impact on the environment as well as a burden on treatment capacity. Various characterization methods are being developed to diagnose the generation mechanism and physical and chemical properties of laser cutting secondary products in real time and to secure technologies for collecting and removing dispersed particles and aerosols in water. This study introduces a real-time laser cutting secondary product characteristic evaluation method that can identify the key mechanisms of secondary product generation by analyzing the plasma formation process on laser cutting surface and behavior of aerosol, underwater dispersed particles produced by secondary products, as well as physical and chemical properties in real time with various measurement technologies such as Optical Emission Spectrometer (OES), Particle Size Analyzer (PSA), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM) and Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (ICP-TOF-MS).
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