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        검색결과 72

        1.
        2024.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Scanning probe microscopy (SPM) has become an indispensable tool in efforts to develop the next generation of nanoelectronic devices, given its achievable nanometer spatial resolution and highly versatile ability to measure a variety of properties. Recently a new scanning probe microscope was developed to overcome the tip degradation problem of the classic SPM. The main advantage of this new method, called Reverse tip sample (RTS) SPM, is that a single tip can be replaced by a chip containing hundreds to thousands of tips. Generally for use in RTS SPM, pyramid-shaped diamond tips are made by molding on a silicon substrate. Combining RTS SPM with Scanning spreading resistance microscopy (SSRM) using the diamond tip offers the potential to perform 3D profiling of semiconductor materials. However, damage frequently occurs to the completed tips because of the complex manufacturing process. In this work, we design, fabricate, and evaluate an RTS tip chip prototype to simplify the complex manufacturing process, prevent tip damage, and shorten manufacturing time.
        4,000원
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study develops a model that can estimate travel speed of each movement flow using deep-learning-based probe vehicles at urban intersections. METHODS : Current technologies cannot determine average travel speeds for all vehicles passing through a specific real-world area under obseravation. A virtual simulation environment was established to collect information on all vehicles. A model estimate turning speeds was developed by deep learning using probe vehicles sampled during information processing time. The speed estimation model was divided into straight and left-turn models, developed as fully-offset, non-offset, and integrated models. RESULTS : For fully-offset models, speed estimation for both straight and left-turn models achieved MAPE within 10%. For non-offset models, straight models using data drawn from four or more probe vehicles achieved a MAPE of less than 15%. The MAPE for left turns was approximately 20%. CONCLUSIONS : Using probe-vehicle data(PVD), a deep learning model was developed to estimate speeds each movement flow. This, confirmed the viability of real-time signal control information processing using a small number of probe vehicles.
        4,000원
        3.
        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
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to perform a quantitative analysis of Forward Collision Warning and crash frequency using heavy vehicle driving data collected in expressway driving environments, and to classify the driving environments where Forward Collision Warnings of heavy vehicles occur for accident-prone areas and analyze their occurrence characteristics. METHODS : A bivariate Gaussian mixture model based on inter-vehicle distance gap and speed-acceleration parameters is used to classify the environment in which Forward Collision Warning occurs for heavy vehicles driving on expressways. For this analysis, Probe Vehicle Data of 80 large trucks collected by C-ITS devices of Korea Expressway Corporation from May to June 2022. Combined with accident information from the past five years, a detailed analysis of the classified driving environments is conducted. RESULTS : The results of the clustering analysis categorizes Forward Collision Warning environments into three groups: Group I (highdensity, high-speed), Group II (high-density, low-speed), and Group III (low-density, high-speed). It reveals a positive correlation between Forward Collision Warning frequency and accident rates at these points, with Group I prevailing. Road characteristics at sites with different accident incidences showed that on-ramps and toll gates had high occurrences of both accidents and warnings. Furthermore, acceleration deviation at high-accident sites was significant across all groups, with variable speed deviations noted for each warning group. CONCLUSIONS : The Forward Collision Warning of heavy vehicles on expressways is classified into three types depending on the driving environment, and the results of these environmental classifications can be used as a basis for building a road environment that reduces the risk of crashes for heavy vehicles.
        4,000원
        5.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulfur and nitrogen co-doped carbon dots (NSCDs) were quickly synthesized by the microwave-assisted method from triammonium citrate and thiourea. NSCDs showed a quantum yield of 11.5% with excitation and emission bands at 355 and 432 nm, respectively. Also, a fluorescence quenching was observed in the presence of Pb(II) ions, and the as-synthesized CDs were used as a sensitive probe for detecting Pb(II) in water and food samples. The results showed the optimal conditions for Pb(II) determination were CDs concentration of 0.02 mg mL− 1 at pH 6.0–7.0 and an incubation time of 20 min. The relative fluorescence intensity of NSCDs was proportional to Pb(II) concentrations in the range of 0.029–2.40 and 2.40–14.4 μmol L− 1 with a correlation coefficient (R2) of 0.998 and 0.955, respectively, and a detection limit of 9.2 × 10– 3 μmol L− 1. Responses were highly repeatable, with a standard deviation below 3.5%. The suggested method demonstrates the potential of a green, fast, and low-cost approach for Pb(II) determination in water, tea, and rice samples with satisfying results.
        4,000원
        7.
        2023.05 구독 인증기관·개인회원 무료
        Our research team has developed a gamma ray detector which can be distributed over large area through air transport. Multiple detectors (9 devices per 1 set) are distributed to measure environmental radiation, and information such as the activity and location of the radiation source can be inferred using the measured data. Generally, radiation is usually measured by pointing the detector towards the radioactive sources for efficient measurement. However, the detector developed in this study is placed on the ground by dropping from the drone. Thus, it does not always face toward the radiation source. Also, since it is a remote measurement system, the user cannot know the angle information between the source and detector. Without the angle information, it is impossible to correct the measured value. The most problematic feature is when the backside of the detector (opposite of the scintillator) faces the radiation source. It was confirmed that the measurement value decreased by approximately 50% when the backside of the detector was facing towards the radiation source. To calibrate the measured value, we need the information that can indicate which part of the detector (front, side, back) faces the source. Therefore, in this study, we installed a small gamma sensor on the backside of the detector to find the direction of the detector. Since this sensor has different measurement specifications from the main sensor in terms of the area, type, efficiency and measurement method, the measured values between the two sensors are different. Therefore, we only extract approximate direction using the variation in the measured value ratio of the two sensors. In this study, to verify the applicability of the detector structure and measurement method, the ratio of measured values that change according to the direction of the source was investigated through MCNP simulation. The radioactive source was Cs-137, and the simulation was performed while moving in a semicircular shape with 15 degree steps from 0 degree to 180 degrees at a distance of 20 cm from the center point of the main sensor. Since the MCNP result indicates the probability of generating a pulse for one photon, this value was calculated based on 88.6 μCi to obtain an actual count. Through the ratio of the count values of the two sensors, it was determined whether the radioactive source was located in the front, side, or back of the probe.
        8.
        2022.10 구독 인증기관·개인회원 무료
        When the nuclear accident like the Fukushima is occurred, it is required to immediately determine the location of radioactive materials and their activities. Various studies related the unmanned technique to detect and characterize the contaminated area have been conducted. The Korea Institute of Nuclear Nonproliferation and Control (KINAC) has developed a new gamma detection system which consists of nine probes using a silicon photomultiplier (SiPM) and plastic scintillator. The probe is the small gamma detector designed to be carried and dropped near the accident area by the unmanned aerial vehicle. In this paper, we developed the improved design related to the angular dependence of the radioactive contamination detection system with the purpose of increasing the detection efficiency. The detection efficiency, radiation shielding and back-scattering varies depending on the direction of incidence of radiation because the probe has vertical structure of consisting scintillator, photomultiplier, and electric circuits. That is, when the experimental conditions are same except the direction of gamma probe, the result of measurements is different. It causes errors in measuring the radioactivity and location of the radioactive source. Since the direction of the probe is arbitrarily determined during the deployment of the probe through the unmanned aerial vehicle, it is considered changing the design of the scintillator from a conventional 1.0" × 1.0" Φ cylindrical shape to a 1.0" Φ spherical shape. In case of using the spherical scintillator, it is confirmed that angular dependence was reduced through MCNP simulation. The difference in the measurement depending on the direction of the probe could be reduced through additional structure design. Finally, we hope that the developed detection system which has the probes with spherical shape of scintillator can measure the radioactivity and location of the radioactive source in a range of about 100 × 100 m2 by measuring for at least 5 minutes. The field test at Fukushima area will be carried out with JAEA members in order to prove the feasibility of the new system.
        9.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fescues, which are widely cultivated as grasses and forages around the world, are often naturally infected with the endophyte, Epichloë. This fungus, transmitted through seeds, imparts resistance to drying and herbivorous insects in its host without causing any external damage, thereby contributing to the adaptation of the host to the environment and maintaining a symbiosis. However, some endophytes, such as E. coenophialum synthesize ergovaline or lolitrem B, which accumulate in the plant and impart anti-mammalian properties. For example, when livestock consume excessive amounts of grass containing toxic endophytes, problems associated with neuromuscular abnormalities, such as convulsions, paralysis, high fever, decreased milk production, reproductive disorders, and even death, can occur. Therefore, pre-inoculation with non-toxic endogenous fungi or management with endophyte-free grass is important in preventing damage to livestock and producing high-quality forage. To date, the diagnosis of endophytes has been mainly performed by observation under a microscope following staining, or by performing an immune blot assay using a monoclonal antibody. Recently, the polymerase chain reaction (PCR)-based molecular diagnostic method is gaining importance in the fields of agriculture, livestock, and healthcare given the method’s advantages. These include faster results, with greater accuracy and sensitivity than those obtained using conventional diagnostic methods. For the diagnosis of endophytes, the nested PCR method is the only available option developed; however, it is limited by the fact that the level of toxic alkaloid synthesis cannot be estimated. Therefore, in this study, we aimed to develop a triplex real-time PCR diagnostic method that can determine the presence or absence of endophyte infection using DNA extracted from seeds within 1 h, while simultaneously detecting easD and LtmC genes, which are related to toxic alkaloid synthesis. This new method was then also applied to real field samples.
        4,000원
        10.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Among the research of Chinese Characters, there is a long history of the study of “the six categories of Chinese characters,” also a lot of research achievements have been accumulated from the past. Since the Qing Confucian Dai Zhen put forward the theory of “Four Noumenon and Two Uses,” advocated that the Transformed Cognates and Rebus are as the methods of using characters. The debates have been raised once again among different parties. Among them, the one with the most divergent opinions is the usage of “Transformed Cognates.” At the end of the Qing Dynasty and the beginning of the Republic of China, Mr. Zhang Taiyan made a theory from the perspective of the migrating of language. “The transformed Cognates, means that a new character created by changing the tone or the rhythm of the original character,” said Zhang. He clearly stated” a new character created,” regarded that “Transformed cognates” as a practice of creating new characters due to the transfers of sound. Which has always been seen as an important promoter of the theory. However, the subsequent researchers who also sat at the feet of Zhang have two different understandings and interpretations of “the method of using the character” and “the method of creating a character”. This article attempts to sort out the relevant discussion of Mr. Taiyan’s theory and restore the background of the time that Zhang made it. Also discussing the different interpretation perspectives of Zhang’s Transformed Cognates Theory by subsequent scholars in Taiwan. Finally, propose the author’s observations and conclusions.
        9,000원
        11.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Zhang Yan-Yuan’s Fa Shu Yao Lu(法书要录) written in the Tang dynasty, is an important compilation of calligraphic theory from the Tang dynasty and before. With his own insight and vision in the art of calligraphy, as well as his rich family collection and other unique natural conditions, the editor, with a heart to pass on traditional culture and art, took the essence from the vast literature, extracted the essence of it, and worked tirelessly to compile it into a huge volume. The editor does not say a word in the book, but through the selection and abandonment of the content, the order in which the content is presented, the book is logically clear, right and wrong, regardless of its own position and viewpoint. From the overall viewpoint of the book, the content emphasises art over technique; highlights its heritage and historicity from a cultural perspective; establishes the authentic status of Two wangs by declaring the banner; collates, catalogues, examines, discerns forgeries, criticises, authenticates, legends, and narrates different perspectives and aspects of the art of calligraphy by adopting different styles of writing at large; while focusing on a comprehensive system of information from eight dimensions, with clear priorities, prominent views, and The book also focuses on a comprehensive and systematic approach to the material in eight dimensions, with a clear distinction between major and minor points of view, either narrating or discussing, or writing or editing, showing in three dimensions the profoundness of ancient Chinese calligraphic theory and the orthodox calligraphic thought of respecting Two wangs. Secondly, the book also has a positive historical value in terms of preserving valuable documents, deconstructing historical documents to preserve their authenticity, promoting the orthodox status of Two wangs calligraphy, and establishing a paradigm of compilation style for future generations. Of course, Zhang Yan-Yuan could not have done it all on his own, and there are regrets in the choice of titles and unsatisfactory classification of documents in Fa Shu Yao Lu(法书要录), but the flaws do not obscure the merits, and his theoretical contributions to calligraphy are indelible.
        4,800원
        12.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Liushu Jingwei is a dictionary of Chinese characters written by Hong Yang-ho at the end of the Joseon Dynasty. Ji Yun of the Qing Dynasty compared this book with Wang Anshi’s Zishuo in the Northern Song Dynasty in his postscript, and gave a high evaluation. Zishuo had long been lost, and people today have a collection of lost works. After a comparative reading, it can be seen that the two books have similarities and differences. A comparative study of Zishuo and Liushu Jingwei will help to further understand the similarities and differences in the interpretation of Chinese and Korean regular characters, and it is also meaningful for the study of the spread of Chinese characters in Korea.
        4,200원
        14.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated non-graphitizable hard carbon using orange peel with mesoporous structure has been prepared by pyrolyzation at 700, 800, 900 °C using chemical activation method. The activated orange peel-derived hard carbon has been characterized for its mesoporous and disordered structure. TG-DSC gives the information for the changes about sample composition and thermal stability of the materials. Increasing the carbonization temperature for orange peel precursor using NaOH as activating agent, elevates the pore diameter, which thereby facilitating the insertion of Na+. Raman and X-ray diffraction confirms the presence of disordered carbon. The surface morphology of the material was analyzed by scanning eletron microsope and nitrogen ( N2) adsorption and desorption analysis give the morphology, mesopore size (3.374, 3.39 and 4 nm) and surace area (60.164, 58.99 and 54.327 m2/g) of the orange peel-derived hard carbon. Hence, this work strongly evidences that the biomass-derived hard carbon with good porosity and paves way of superior electrochemical performance for emerging sodium ion batteries.
        4,000원
        18.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Defects in most structures can be generated not only on outside but also on inside or on the back-side during the manufacturing or construction process. Also they cause the growth of defects due to operation of various complex environments and structures will be destroyed eventually. In order to improve the reliability of the structure, the detection and size-estimation of defects should be investigated. In this paper, as an extension of previous studies on surface defects, two-dimensional artificial backside cracks (blind cracks) into paramagnetic material were evaluated by using the same aluminum probe. The potential drop at the defect position is distributed in the n-shape in the case of the back defect, which is different from results of the surface defect (u-shape). The potential drops at the defect position are measured with the largest value. The potential drop ratio (Vcmax/Vs) for the defective position is used as a parameter to predict the thickness (l) of defect position.
        4,000원
        19.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        선체구조의 품질검사 중 가장 일반적인 방법의 하나는 비파괴검사이다. 하지만 복합소재 선체는 강화재와 수지로 구성된 여러가지 재료가 섞여 있고 또 생산환경과 작업자에 따라 FRP(Fiber-Reinforced Plastics) 제작품질에 차이가 발생할 가능성이 크기 때문에 정확한 검사평가는 쉽지 않은 일이다. 특히 FRP 선박의 경우에는 다른 구조물보다 두께가 매우 두껍고 주로 수척층 공법을 이용하기 때문에 더욱 그렇다. 초음파 탐상의 조건 중 검사체의 밀도가 매우 중요하기 때문에 본 연구에서는 FRP 선박 제작에 널리 사용되고 있는 소재와 유리섬유강화재 중량 비율로 제작된 선박의 외판을 검사체로 선정하고, Pulse-Echo 초음파 탐상기를 활용하여 GFRP(Glass Fiber-Reinforced Plastics) 선체 외판의 초음파 탐상을 위한 적정 조건을 조사하였다. 1.00 MHz, 2.25 MHz, 5.00 MHz 세 종류 탐촉자로 A-Scan 을 실시하였으며 선체 외판의 두께 검사결과와 비교분석함으로써 적정 초음파 탐상 조건을 찾고자 하였다. 연구결과 탐촉자의 초음파 주파수가 높아질수록 수신자의 반사파 음향 속력을 감소시켜야 더 정도 높은 두께 측정 결과를 얻을 수 있었으며, 상대적으로 낮은 초음파 주파수 탐촉자에서 더 적은 오차가 발생함을 확인할 수 있었다.
        4,000원
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