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        검색결과 524

        62.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the effect of isolated lactic acid bacteria (LAB) on the quality of high moisture rye silage. Rye forage (Secale cereale L.) was harvested at the heading stage (27.3% of dry matter (DM)) and cut into approximately 3-5 cm lengths. Then, the forage divided into 4 treatments with different inoculants: 1) No additives (CON); 2) Lactobacillus brevis strain 100D8 at a 1.2 x 105 colony-forming unit (cfu)/g of fresh forage (LBR); 3) Leuconostoc holzapfelii strain 5H4 at a 1.0 x 105 cfu/g of fresh forage (LHO); and 4) Mixture of LBR and LHO (1:1 ratio) applied at a 1.0 x 105 cfu/g of fresh forage (MIX). About 3 kg of forage from each treatment was ensiled into a 20 L mini-bucket silo in quadruplicate for 100 days. After silo opening, silage was collected for analyses of chemical compositions, in vitro nutrient digestibilities, fermentation characteristics, and microbial enumerations. The CON silage had the highest concentrations of neutral detergent fiber and acid detergent fiber (p = 0.006; p = 0.008) and a lowest in vitro DM digestibility (p < 0.001). The pH was highest in CON silage, while lowest in LBR and MIX silages (p < 0.001). The concentrations of ammonia-N, lactate, and acetate were highest in LBR silage (p = 0.008; p < 0.001; p < 0.001). Propionate and butyrate concentrations were highest in CON silage (p = 0.004; p < 0.001). The LAB and yeast counts were higher in CON and LHO silages compare to LBR and MIX silages (p < 0.001). However, the mold did not detect in all treatments. Therefore, this study could conclude that L. brevis 100D8 and Leu. holzapfelii strain 5H4 can improve the digestibility and anti-fungal activity of high moisture rye silage.
        4,000원
        63.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cordyceps militaris mycelium extracts containing high amounts of cordycepin were evaluated in vitro for their antiinflammatory and tumor cell growth-inhibitory activities. All extracts dose dependently inhibited the increased production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), and β-hexosaminidase in lipopolysaccharide (LPS)-stimulated inflammatory cells. All extracts were evaluated for anti-proliferative activity against normal RBL-2H3 cells and diverse types of cancer cell lines, including HCT, MC5-7, U-87MG, AGS, and A549 cells. The extract showed the strongest growth inhibition (IC50 = 28.13 μg/mL) relative to vehicle-treated control cells against fibrosarcoma (MC5-7). We have demonstrated anti-inflammatory activity of C. militaris via inhibition of NO, ROS production, and β-hexosaminidase release in activated cells. C. militaris mycelium extract was also evaluated mechanistically and found to exert six types of anti-cancer activity, confirming its pharmacological potential. Our study suggests C. militaris use as a potential source of anti-inflammatory and anticancer agents. C. militaris may also be considered a functional food.
        4,000원
        64.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the era of Covid-19 provoked the demand for online learning environments, research on the use of IT technologies in the teaching of Chinese is also drawing attention. This paper presents an overview of studies on mobile applications for learning Chinese in Korea, China, and the U.S.. This study aims to identify the current status of research on mobile applications for learning Chinese in Korea, and suggests directions for further research. In the review, a total of 135 studies were closely examined based on the year of publication, the subject, the method, and the research topic. After this, the features and overall flow of research in each country was identified. The necessity of revitalizing related research in Korea was highlighted. To this end, this study recommends actively conducting research, specifying the characteristics of the research subject, and extending the general process in studies of mobile applications for learning Chinese. This study expects Chinese education research on using various technologies to be further discussed.
        7,700원
        65.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the past decade, there has been phenomenal progress in the field of nanomaterials, especially in the area of carbon nanotubes (CNTs). In this review, we have elucidated a contemporary synopsis of properties, synthesis, functionalization, toxicity, and several potential biomedical applications of CNTs. Researchers have reported remarkable mechanical, electronic, and physical properties of CNTs which makes their applications so versatile. Functionalization of CNTs has been valuable in modifying their properties, expanding their applications, and reducing their toxicity. In recent years, the use of CNTs in biomedical applications has grown exponentially as they are utilized in the field of drug delivery, tissue engineering, biosensors, bioimaging, and cancer treatment. CNTs can increase the lifespan of drugs in humans and facilitate their delivery directly to the targeted cells; they are also highly efficient biocompatible biosensors and bioimaging agents. CNTs have also shown great results in detecting the SARS COVID-19 virus and in the field of cancer treatment and tissue engineering which is substantially required looking at the present conditions. The concerns about CNTs include cytotoxicity faced in in vivo biomedical applications and its high manufacturing cost are discussed in the review.
        5,500원
        66.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The utilization of carbonaceous reinforcement-based polymer matrix composites in structural applications has become a hot topic in composite research. Although conventional carbon fiber-reinforced polymer composites (CFRPs) have revolutionized the composite industry by offering unparalleled features, they are often plagued with a weak interface and lack of toughness. However, the promising aspects of carbon fiber-based fiber hybrid composites and hierarchical composites can compensate for these setbacks. This review provides a meticulous landscape and recent progress of polymer matrixbased different carbonaceous (carbon fiber, carbon nanotube, graphene, and nanodiamond) fillers reinforced composites’ mechanical properties. First, the mechanical performance of neat CFRP was exhaustively analyzed, attributing parameters were listed down, and CFRPs’ mechanical performance barriers were clearly outlined. Here, short carbon fiber-reinforced thermoplastic composite was distinguished as a prospective material. Second, the strategic advantages of fiber hybrid composites over conventional CFRP were elucidated. Third, the mechanical performance of hierarchical composites based on carbon nanotube (1D), graphene (2D) and nanodiamond (0D) was expounded and evaluated against neat CFRP. Fourth, the review comprehensively discussed different fabrication methods, categorized them according to performance and suggested potential future directions. From here, the review sorted out three-dimensional printing (3DP) as the most futuristic fabrication method and thoroughly delivered its pros and cons in the context of the aforementioned carbonaceous materials. To conclude, the structural applications, current challenges and future prospects pertinent to these carbonaceous fillers reinforced composite materials were elaborated.
        8,000원
        67.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In preparation of porous carbon materials microwave oven brightening is one of the warming modes used ever. The various procedures that take place in microwave combustion process include carbonization, incitation, and recovery and thus carbon is defined. This paper compares ideal conditions of traditional warming methods, as well as their implementation potential, losses, and specifications. This porous carbon with heat treatment possesses various properties and they are well suited for energy applications which require constrained space such as hydrogen storage in solid-state and supercapacitors. The enhanced properties are chemical and thermal stability, ready availability, low framework density and ease of processability. The recent trend in class of porous carbons is Activated Carbons that are employed traditionally as adsorbents or catalyst supporters but currently, they found potent applications in fabricating for hydrogen storage materials and supercapacitors. These activated carbons are much enhanced form in class of porous carbon materials and they possess the capability to enable hydrogen economy, where the energy carrier is hydrogen. Therefore, the utility of activated carbons as a source for energy storage experiences a rapid growth at current trend and they possess significant advances. This investigation is based on detailed cost development data and electrical imperativeness applications.
        5,700원
        68.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanosized rutile titanium dioxide (TiO2) is used in inorganic pigments and cosmetics because of its high whiteness and duality. The high quality of the white pigments depends on their surface coating technique via the solgel process. SiO2 coatings are required to improve the dispersibility, UV-blocking, and whiteness of TiO2. Tetraethyl orthosilicate (TEOS) is an important coating precursor owing to its ability to control various thicknesses and densities. In addition, we use Na2SiO3 (sodium silicate) as a precursor because of its low cost. Compared to TEOS, which controls the pH using a basic catalyst, Na2SiO3 controls the pH using an acid catalyst, giving a uniform coating. The coating thickness of TiO2 is controlled using a surface modifier, cetrimonium bromide, which is used in various applications. The shape and thickness of the nanosized coating layer on TiO2 are analyzed using transmission electron microscopy, and the SiO2 nanoparticle behavior in terms of the before-and-after size distribution is measured using a particle size analyzer. The color measurements of the SiO2 pigment are performed using UV-visible spectroscopy.
        4,000원
        70.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To solve the pathological problems of the musculoskeletal system based on evidence, a sophisticated analysis of human motion is required. Traditional optical motion capture systems with high validity and reliability have been utilized in clinical practice for a long time. However, expensive equipment and professional technicians are required to construct optical motion capture systems, hence they are used at a limited capacity in clinical settings despite their advantages. The development of information technology has overcome the existing limit and paved the way for constructing a motion capture system that can be operated at a low cost. Recently, with the development of computer vision-based technology and optical markerless tracking technology, webcam-based 3D human motion analysis has become possible, in which the intuitive interface increases the user-friendliness to non-specialists. In addition, unlike conventional optical motion capture, with this approach, it is possible to analyze motions of multiple people at simultaneously. In a non-optical motion capture system, an inertial measurement unit is typically used, which is not significantly different from a conventional optical motion capture system in terms of its validity and reliability. With the development of markerless technology and advent of non-optical motion capture systems, it is a great advantage that human motion analysis is no longer limited to laboratories.
        4,000원
        71.
        2022.05 구독 인증기관·개인회원 무료
        Prior to dismantling a nuclear facility, full site characterization should be carried out to identify basic data for various stages of decommissioning, such as deregulation of sites and structures, selection of decontamination technology, decommissioning methods, and waste management and disposal. Radiological characterization is implemented through information collection, on-site measurement, sampling and analysis, and theoretical calculations and proven codes for radioactive material at the time of decommissioning of the nuclear facility. There are issues in that it takes a lot of time and money to collect and analyze samples for characterization of contaminated sites and radioactive structures. Therefore, in the entire process of decommissioning a nuclear facility, a technology that can quickly measure the radiological characteristics of various decommissioning objects and wastes on site is required. In this project, the utilization of gamma cameras that can be analyzed in the field for quick and accurate characteristic evaluation at the dismantling site was studied. A gamma camera, iPIX from Canberra (Now it became Mirion Technology), was tested in this study. It is a unique gamma imager, which have a CdTe sensor with TIMEPIX chip and a coded aperture collimator, quickly locates and identifies low to high level radioactive sources from a distance while estimating the dose rate at the measurement point in real time. It also can be combined with CZT sensor which called iPIX-NID (nuclide Identification) provides users with clear understanding of radionuclides presence with no need of any spectroscopic knowledge. iPIX with iPIX-NID convert the gamma camera into a hot-spot detector with radionuclide information. To verify the applicability of a gamma camera in Nuclear power plant, it was implemented to Kori unit-1 which was permanently shut down from 2017. Various Systems were observed at restricted area including reactor cooling system, boron recovery system, residual heat removal system, containment spray system, and etc. The locations of hot spots were clearly revealed by iPIX and these results can be used for selecting the locations of destructive samples and help to decide the conservative decision making. Condensate water systems in turbine building were also observed by a gamma camera and showed no nuclide. Based on this preliminary gamma camera applications, further investigation and tests will be carried out to Kori Unit-1.
        72.
        2022.05 구독 인증기관·개인회원 무료
        Dry storage cask facilities are considered for temporary storage of spent nuclear fuels before their final disposal. According to relevant domestic laws and regulations, the integrity and gross defects of the PWR spent fuel must be inspected before they are transferred to the dry cask from a wet storage pool of a nuclear power plant. To meet nuclear safeguards requirements for a spent fuel transportation, the KINAC has been working to develop a simple and convenient Non-destructive Testing (NDT) equipment to verify the integrity and gross defects of the spent fuel assembly. This study was conducted in two processes. The first stage is to review the current NDT techniques conducted in the nuclear fuel manufacturing process. During the manufacturing process, the Ultrasonic testing (UT) and Eddy Current Testing (ECT) technique are used for detecting the cracks or foreign materials in a cladding of a fresh fuel. During an over-haul period after an end of one fuel cycle, the sipping test of the spent fuel is performed for detecting the failed fuel assemblies. If it is determined through the sipping test whether any fuel assembly contains a failed fuel rod, the failed fuel rod of lots of fuel rods in the assembly is found out using the UT instrument. The ECT is used for detecting the internal defects and oxide layer thickness of a fuel cladding. Because the UT and ECT are the wellknown technique and has already been employing for the spent fuel inspection, we adopted the UT and ECT technique for development of a new instrument for nuclear safeguards verification. The second stage is to design the UT and ECT equipment in consideration of nuclear safeguards activities in the spent fuel pool. For nuclear safeguards inspection, irradiated fuel or non-fuel items are distinguished. Thus, verification equipment newly designed using the UT and ECT should detect not only a failed rod, but also a false tube, or a false rod, or a different material from a cladding. New probe and signal processing methods are developed to achieve these goals. The design of UT and ECT probes are preferentially carried out according to technical requirements – the probe thickness including a damper material should be less than 1.0 mm - and the study on analyzing signal distortion caused from material difference will be conducted for development of the safeguards inspection equipment. Detailed results of our study will be discussed in this conference.
        76.
        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
        77.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanomaterials (NMs) are gradually becoming pervasive in the modern world, entering every application for improving the quality of life. Multifaceted uses of NMs in curing diseases, biomedical instrumentation, bioimaging, drugs, and gene delivery, display devices, nanosensors, and biomarkers in several fields ranging from agriculture to industries, healthcare, and environment, have been well recognized. Carbon-based nanomaterials (CNMs) constitute a major type of NMs with broad-spectrum applications including their uses in agriculture. These are synthesized in large quantities via synthetic and biological approaches. Biological approaches are gaining appreciation and momentum, owing to the advantages associated with them, major being their environment friendly or ‘Green’ nature. This topical review focuses on the preparation of CNMs using natural resources, i.e., using the Green Nanotechnology. The up-to-date compilation presented here includes most of the popular green technological methods of producing the CNMs and their immediate uses as anticancer agents, in bio-labelling, as biosensors, in bio-remediation, in cell imaging, in fluorescent inks, and fluorescent dyes, as plant growth inducing agents, in nano-probes, in light-emitting devices and other applications. It is intended to update the reader with the state-of-the-art knowledge about the green technological methods for synthesizing CNMs, their uses, current trends, challenges, and future outlook on the topic.
        6,900원
        78.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The carbon-based nanostructures are in limelight due to their widespread applications in nano-to-micro-scale technologies. The carbon dots are known for their unique physical, electrical, optical, chemical and biological properties. The carbon dots (CDs) are being produced through several well-developed synthesis methods, one of which is the green sonochemical. This method is preferred over others because it is a green source of energy, facile, fast, low-temperature process, non-toxic and less expensive. Despite the fact of using 90% less energy than other methods, this method has been overlooked in the published literature. It is possible to prepare pure and doped CDs of low toxicity and controlled physicochemical properties through sonochemical method. In recent years, sonochemically produced CDs have been tuned and characterized for a variety of applications. This review has explored the merits and demerits of sonochemical method in comparison to the other methods for the synthesis of pure CDs and their nanocomposites. The role of multiple factors in tailoring the specific parameters of CDs for their application in antibacterial, polymerization, tissue engineering, catalysis, bio-imagining, supercapacitors, drug delivery and electric devices is also elaborated in this review. This review also concludes on future directions in the applications of sonochemically produced CDs.
        5,100원
        79.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지하의 단층들이 지표면까지 도달하지 못하면 단층의 유무를 인지 못하는 경우가 있다. HVSR 분석법으로 지표 면 아래 단층의 존재를 판별할 수 있는지 살펴보기 위해 포항분지 흥해지역 동편의 곡강단층을 통과하는 지역을 선정 하여 연구를 진행하였다. 교차하는 두개의 측선에서 조밀하게 관측한 배경잡음으로 HVSR 분석을 통해 공명주파수를 산정하였다. 연구지역 내 시추 자료의 기반암 깊이 정보와 시추 지역의 공명주파수를 이용해 상관식을 도출한 후 두 측선에서의 공명주파수를 상관식에 적용해 기반암 심도를 산출하였다. HVSR 분석 결과 두 측선에서 기반암 심도가 급 격히 변하는 곳이 있다. 특히 곡강단층 인근에서 공명주파수가 급격히 변화하였고, 기존에 알려진 단층이 없는 지역에 서도 공명주파수와 기반암 심도가 급격히 변화하는 곳이 있음을 알 수 있었다. 이 형상은 이전에 알려지지 않은 blind fault와 관련이 있을 것으로 사료된다. 본 연구는 지표면에서 인식하지 못하는 단층을 식별하기 위한 HVSR 방법의 적 용 가능성을 확인하였다.
        4,200원
        80.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 들어 컴퓨터 및 소프트웨어 기술의 발달로 전산모사 관련 연구가 급격하게 늘어나고 있는데, 특히 원자의 개수 및 모델 크기의 문제로 기존에는 많은 제약을 받던 고분자 관련 다양한 전산모사 결과들이 발표되고 있다. 본 연구에서 는 고분자 소재를 필름형태의 분리막으로 활용하기 위한 중요한 특성 중 하나인 기계적 특성을 분자동역학 전산모사를 이용 하여 분석하고자 하는 연구를 진행하였다. 이를 위하여 이미 관련 물성이 널리 보고되어 있는 상용 고분자 소재인 polyethylene (PE)과 polystyrene (PS)을 대상으로 선정하여 주쇄길이 차이를 통한 각 고분자들의 인장특성을 비교하였고, 최종적 으로 분자동역학 전산모사의 기계적 특성 분석이 적합한지 확인하고자 하였다. 밀도, radius of gyration, scattering 분석을 통 해 본 연구에서 제작된 모델이 실제 실험에서 얻어진 기계적 특성 경향과 잘 일치함을 알 수 있었고, 따라서 분자동역학 전 산모사를 이용한 기계적 특성 분석이 다양한 고분자 소재들의 분자 구조에 따른 기계적 특성을 예측할 수 있게 해주며, 실제 실험에서는 적용하기 어려운 다양한 변수들을 반영한 기계적 특성 해석도 가능하게 해 줄 것으로 기대된다.
        4,000원
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