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        검색결과 525

        121.
        2020.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the present investigation we show the effect of Al doping on the length, size, shape, morphology, and sensing property of ZnO nanorods. Effect of Al doping ultimately leads to tuning of electrical and optical properties of ZnO nanorods. Undoped and Al-doped well aligned ZnO nanorods are grown on sputtered ZnO/SiO2/Si (100) pre-grown seed layer substrates by hydrothermal method. The molar ratio of dopant (aluminium nitrate) in the solution, [Al/Zn], is varied from 0.1 % to 3 %. To extract structural and microstructural information we employ field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods show preferred orientation of ZnO <0001> and are well aligned vertically. The effects of Al doping on the electrical and optical properties are observed by Hall measurement and photoluminescence spectroscopy, respectively, at room temperature. We observe that the diameter and resistivity of the nanorods reach their lowest levels, the carrier concentration becomes high, and emission peak tends to approach the band edge emission of ZnO around 0.5% of Al doping. Sensing behavior of the grown ZnO nanorod samples is tested for H2 gas. The 0.5 mol% Al-doped sample shows highest sensitivity values of ~ 60 % at 250 ˚C and ~ 50 % at 220 ˚C.
        4,000원
        122.
        2020.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        SrMoO4:RE3+ (RE=Dy, Sm, Tb, Eu, Dy/Sm) phosphors are prepared by co-precipitation method. The effects of the type and the molar ratio of activator ions on the structural, morphological, and optical properties of the phosphor particles are investigated. X-ray diffraction data reveal that all the phosphors have a tetragonal system with a main (112) diffraction peak. The emission spectra of the SrMoO4 phosphors doped with several activator ions indicate different multicolor emissions: strong yellow-emitting light at 573 nm for Dy3+, red light at 643 nm for Sm3+, green light at 545 nm for Tb3+, and reddish orange light at 614 nm for Eu3+ activator ions. The Dy3+ singly-doped SrMoO4 phosphor shows two dominant emission peaks at 479 and 573 nm corresponding to the 4F9/2→6H15/2 magnetic dipole transition and 4F9/2→6H13/2 electric dipole transition, respectively. For Dy3+ and Sm3+ doubly-doped SrMoO4 phosphors, two kinds of emission peaks are observed. The two emission peaks at 479 and 573 nm are attributed to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+ and two emission bands centered at 599 and 643 nm are ascribed to 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions of Sm3+. As the concentration of Sm3+ increases from 1 to 5 mol%, the intensities of the emission bands of Dy3+ gradually decrease; those of Sm3+ slowly increase and reach maxima at 5 mol% of Sm3+ ions, and then rapidly decrease with increasing molar ratio of Sm3+ ions due to the concentration quenching effect. Fluorescent security inks based on as-prepared phosphors are synthesized and designed to demonstrate an anticounterfeiting application.
        4,000원
        124.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, unmanned aerial vehicles (UAV, Drone) are highly regarded for their potential in the agricultural field, and research and development are actively conducted for various purposes. Therefore, in this study, to present a framework for tracking research trends in UAV use in the agricultural field, we secured a keyword search strategy and analyzed social network, a methodology used to analyze recent research trends or technological trends as an analysis model applied. This study consists of three stages. As a first step in data acquisition, search terms and search formulas were developed for experts in accordance with the Keyword Search Strategy. Data collection was conducted based on completed search terms and search expressions. As a second step, frequency analysis was conducted by country, academic field, and journal based on the number of thesis presentations. Finally, social network analysis was performed. The analysis used the open source programming language 'Python'. Thanks to the efficiency and convenience of unmanned aerial vehicles, this field is growing rapidly and China and the United States are leading global research. Korea ranked 18th, and bold investment in this field is needed to advance agriculture. The results of this study's analysis could be used as important information in government policy making.
        4,200원
        125.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fluorescent nanoparticles are characterized by their unique properties such as luminescence, optical transparency, and sensitivity to various chemical environments. For example, semiconductor nanocrystals (quantum dots), which are nanophosphors doped with transition metal or rare earth ions, can be classified as fluorescent nanoparticles. Tuning their optical and physico-chemical properties can be carried out by considering and taking advantage of nanoscale effects. For instance, quantum confinement causes a much higher fluorescence with nanoparticles than with their bulk counterparts. Recently, various types of fluorescent nanoparticles have been synthesized to extend their applications to other fields. In this study, State-of-the-art fluorescent nanoparticles are reviewed with emphasis on their analytical and anti-counterfeiting applications and synthesis processes. Moreover, the fundamental principles behind the exceptional properties of fluorescent nanoparticles are discussed.
        4,000원
        126.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The paper introduces KorLex, Korean WordNet, which uses Princeton WordNet (PWN) as a reference model as well as a pivot that provides KorLex with the multilingual interface. Sub-section 2.1 describes the background for which we intended to build KorLex by ourselves, and the motivations for which we selected PWN as a reference model among other wordnets. Sub-sections 2.2 and 2.3 deal with the semantic features that share both PWN and KorLex, and the linguistic features that we attach to KorLex in order to improve Korean Language Processing (KLP). Section 3 presents two representative applications of KorLex in the field of Natural Language Processing: (1) in KLP environment, <Korean Spell/Grammar Checker (KSGC)> that we have developed for the last 30 years, and for which we decided to elaborate KorLex version 1.5 and to attach the sophisticate information of Korean language to the version 2.0; (2) in multilingual environment, <Korean-Korean_Sign_Language Machine Translation (K2KSL MT)>, which would not be successfully developed without the hierarchical semantic structure of KorLex as well as PWN, since the hierarchy enables K2KSL MT to solve logically the notorious ‘data sparseness (= lack of lexicon)’ problem that KSL encounters during the translation process, like in other bilingual or multilingual MT systems.
        7,000원
        127.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Emulsion polymerase chain reaction (PCR) is performed on compartmentalized DNA, allowing a large number of PCR reactions to be carried out in parallel. Emulsion PCR has unique advantages in DNA amplification. It can be applied in many molecular biological assays, especially those requiring highly sensitive and specific DNA amplification. This review discusses the principle of emulsion PCR and its applications in biotechnology. Related technologies are also discussed.
        4,000원
        128.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The applications of information and communication technology (ICT) into real industrial fields are getting great attentions in recent years. More and more industrial practitioners and scientific researchers are conducting studies and trying to adopt the technologies into diverse industrial fields. The purpose of this study is to review the technologies such as big data and smart sensors and to provide application cases in order to facilitate grafting the 4th industrial revolutionary technologies onto the safety and health systems. Based on the comprehensive reviews on literature, reports, and industrial cases, we found that big data technology has been used in industries for investigating work related disease. In addition, digital image technology and drone have been applied to establish safety system in construction industry. Lastly, some companies have tried to apply the technologies to build their own safety and health system.
        4,000원
        129.
        2019.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        룻은 남편과 아들에게 의존된 고대 여성들의 일반적인 존재방식을 쫓지 않고 나오미에 대한 책임과 섬김의 삶을 선택한다. 룻은 고엘과 시형제 결혼을 자신의 상황에서 창조적으로 해석함으로 자신과 나오미 에 대한 삶의 문제를 적극적으로 극복해 나간다. 이런 과정 속에서 룻과 보아스, 그리고 베들레헴 공동체는 상호적인 헤세드를 행하므로 포로기 이후 새롭게 성립되는 이스라엘 공동체의 성격을 하나님을 경외함으로 타자에게 열려있고 헤세드를 행하는 선교적 공동체로 제시 한다. 이와 같이 헤세드는 사람들 사이의 모든 다름과 차이를 넘어서 서로 조화되고 화해할 수 있도록 한다. 상호적 헤세드를 통해 이주여성 들은 이주국 공동체와 관계를 형성하고 소통할 수 있게 될 것이다. 헤세드는 공동체의 타자들과 이주국 사람들을 연결시키며, 그로 인해 타자들이 차별받지 않는 공동체의 구성원이 될 수 있는 정의로운 사회의 토대를 마련한다. 그러므로 타인에 대한 나의 책임, 즉 헤세드를 타자에게 행하여야 함을 인식하고 나의 것을 나누고 환대하는 태도야말로 다문화사회의 분열을 봉합하는 중요한 요건이 될 것이다.
        7,000원
        134.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.
        6,900원
        139.
        2019.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Aluminum nitride (AlN) has versatile and intriguing properties, such as wide direct bandgap, high thermal conductivity, good thermal and chemical stability, and various functionalities. Due to these properties, AlN thin films have been applied in various fields. However, AlN thin films are usually deposited by high temperature processes like chemical vapor deposition. To further enlarge the application of AlN films, atomic layer deposition (ALD) has been studied as a method of AlN thin film deposition at low temperature. In this mini review paper, we summarize the results of recent studies on AlN film grown by thermal and plasma enhanced ALD in terms of processing temperature, precursor type, reactant gas, and plasma source. Thermal ALD can grow AlN thin films at a wafer temperature of 150~550 oC with alkyl/amine or chloride precursors. Due to the low reactivity with NH3 reactant gas, relatively high growth temperature and narrow window are reported. On the other hand, PEALD has an advantage of low temperature process, while crystallinity and defect level in the film are dependent on the plasma source. Lastly, we also introduce examples of application of ALD-grown AlN films in electronics.
        4,200원
        140.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        동물플랑크톤은 식물플랑크톤 및 기타 소형 미생물을 섭식하고, 고차 생물군집에 포식되어 일차생산과 상위 영양단계를 연결하는 중추적인 연결고리 역할자로 수생태계 내 물질 및 에너지 순환 구조와 기능을 이해하는데 필수적인 요소로 여겨지고 있다. 하지만, 동물플랑크톤은 분류군에 따라 상이한 크기와 유영능력, 그에 따른 다양한 서식 특성을 가지고 있어, 식물플랑크톤에 비해 다소 복잡한 채집 및 분석방법이 요구된다. 정확한 동물플랑크톤 정량화를 위해서는 종특이적인 분포를 고려하여 장소를 선정하 고 적합한 도구 (채수기, 플랑크톤 네트 등)를 이용하여 시료를 채집해야 할 필요가 있으며, 동정 및 계수 중에 발생 할 수 있는 오차를 최소화하기 위해서는 고정법과 부차시료에 대한 고려도 중요하다. 본 논문에서는 현재 사용되고 있는 대표적인 동물플랑크톤 정량채집방법 및 시료처리방법의 장·단점을 소개하여 연구 목적에 부합하는 방법을 선택, 적용할 수 있도록 가이드라인을 제시하고자 하였다.
        4,600원