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Growth of Carbon Nanotube by Chemical Vapor Deposition (화학기상증착법에 의한 탄소 나노튜브의 성장)

  • 은광용;이광렬;백영준;이재갑;정민재;박종완
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2001.04a
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    • pp.34-34
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    • 2001
  • 열CVD법에 의하여 아세틸렌 가스를 탄소 원으로 사용한 탄소 나노튜브의 성장거동을 조사하였다. 닉켈 분말의 직경을 15nm 내지 90nm 범위로 조정하여 기판 에 촉매로 배열하였다. 탄소 나노튜브는 질소, 수소, 알곤, 암모니아 등 여러가지의 가스 분위기에서 증착되었으며 이들 가스의 혼합 분위기가 탄소나 노튜브의 성장에 미치는 영향을 조사하였다. 증착은 대기압 압력하에서 85$0^{\circ}C$ 의 온도에서 이루어졌다. 순수한 질소 분위기에서는 탄소 나노튜브의 성장이 이루어지지 않고 두꺼운 탄소 층이 기판 위에 중착되었다. 이 조건에서는 탄소로 뒤덮혀진 닉켈 입자가 탄소 나노튜브 형성의 촉매 역할을 담당하지 못했다. 그러나 질소와 수소의 혼합분위기에서는 수소의 농도가 증가함에 따라 탄소 나노튜브의 성장이 증진되었다. 순수한 수소 분위기에서는 일정한 방향이 없이 꼬여진 탄소 나노튜브가 성장되었다. 탄소 나노튜브의 성장은 분위기 가스로 암모니아를 사용하였을 때 훨씬 더 증진되었다. 수직으로 배열된 탄소 나노튜료를 암모니아 분위기에서는 성장시킬 수 있었으나 암모니아와 같은 비율의 수소와 질소 가스의 혼합 분위기 하에서 는 탄소 나노튜브의 성장을 얻을 수 없었다. 이러한 결과를 여기에서는 닉켈 촉매의 표면에 과도하게 석출된 탄소의 촉매 passivation으로 설명하였다. 탄소 나노튜브의 증착을 위해서는 아세틸렌 가스의 분해율이 너무 과도하지 않게 즉 촉매의 표면이 과도한 탄소의 증착으로 수동태화 되지않도록 조절되어야 한다는 것이다. 이 연구결과는 분위기 가스의 조성이 탄소 나노튜브의 성장에 있어서 그 반웅 kinetics에 큰 영향을 미친다는 것을 잘 보여주고 있다. 또한 암모니아 분위기에서는 촉매 닉켈입자 표면에 질화물층이 형성되어 탄소 나노튜브의 성장에 영향을 미쳤다는 것도 알 수 있었다.며 실제 가공업체에서도 터짐 문제가 발견되지 않았다. 결론적으로 표면층의 인장강도가 패션/구부림에 가장 중요한 변수로 작용하며 어떠 한 형태로 표면층의 인장강도를 향상시킬 경우 침엽수 펄프는 재생펄프로 대체가 가능 할 것으로 판단된다.하는 통계기법 중의 하나인 주성분회귀분석을 실시하였다. 주성분 분석은 여러 개의 반응변수에 대하여 얻어진 다변량 자료의 다차원적인 변 수들을 축소, 요약하는 차원의 단순화와 더불어 서로 상관되어있는 반응변수들 상호간 의 복잡한 구조를 분석하는 기법이다. 본 발표에서는 공정 자료를 활용하여 인공신경망 과 주성분분석을 통해 공정 트러블의 발생에 영향 하는 인자들을 보다 현실적으로 추 정하고, 그 대책을 모색함으로써 이를 최소화할 수 있는 방안을 소개하고자 한다.금 빛 용사 둥과 같은 표면처리를 할 경우임의 소재 표면에 도금 및 용 사에 용이한 재료를 오버레이용접시킨 후 표면처리를 함으로써 보다 고품질의 표면층을 얻기위한 시도가 이루어지고 있다. 따라서 국내, 외의 오버레이 용접기술의 적용현황 및 대표적인 적용사례, 오버레이 용접기술 및 용접재료의 개발현황 둥을 중심으로 살펴봄으로서 아직 국내에서는 널리 알려지지 않은 본 기 술의 활용을 넓이고자 한다. within minimum time from beginning of the shutdown.및 12.36%, $101{\sim}200$일의 경우 12.78% 및 12.44%, 201일 이상의 경우 13.17% 및 11.30%로 201일 이상의 유기의 경우에만 대조구와 삭제 구간에 유의적인(p<0.05) 차이를 나타내었다.는 담수(淡水)에서 10%o의 해수(海水)로 이주된지 14일(日) 이후에 신장(腎臟)에서 수축된 것으로 나타났다. 30%o의 해수(海水)에 적응(適應)된 틸라피아의 평균 신사구체(腎絲球體)의 면적은 담수(淡水)에

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Web 2.0 and Web novels -Focusing on Web-based Romance Novels (웹 2.0 시대와 웹소설 -웹 로맨스 서사를 중심으로)

  • Ryu, Su-Yun
    • Journal of Popular Narrative
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    • v.25 no.4
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    • pp.9-43
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    • 2019
  • Web novels are one of the most actively adapted genre novels under a new medium called the Internet. Research on cultural content implemented on top of digital media is naturally closely related to environmental changes in digital media. The same goes for Web novels sparked by the identity of Web platforms. Especially in the case of web novels, the platform itself that provides them has triggered direct changes in genre code and reading patterns. From this perspective, this thesis wanted to examine the formation process and strategic features of web novels, which became content and products on the web platform environment. First of all, through the formation process ranging from communication novels to Internet novels and web novels, I arranged the transition to digital media and the change of genre novel market. This was an attempt to extract that Web novels not only have continuity as genre novels, but also have a turning point as digital content. Web novels are digital content that internalizes the values of the Web 2.0 era. It should also be a core product that grows the pie in the market in its own right. This paper noted that web novels are content that embodies these consumption values. So this thesis considered about what is the visualization and commercialization strategy of the web-based novels that is currently formed, and what is the current status of the web-based romance novels as the content and the product that is driving OSMU most actively in the process of commercialization. Through this process, I found that the greatest characteristic of web novels as genre novels that have evolved into digital content is their division and crack of genre.

A review of factors that regulate extracellular enzyme activity in wetland soils (습지 토양 내 체외효소 활성도를 조절하는 인자에 대한 고찰)

  • Kim, Haryun
    • Korean Journal of Microbiology
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    • v.51 no.2
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    • pp.97-107
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    • 2015
  • Wetlands constitute a transitional zone between terrestrial and aquatic ecosystems and have unique characteristics such as frequent inundation, inflow of nutrients from terrestrial ecosystems, presence of plants adapted to grow in water, and soil that is occasionally oxygen deficient due to saturation. These characteristics and the presence of vegetation determine physical and chemical properties that affect decomposition rates of organic matter (OM). Decomposition of OM is associated with activities of various extracellular enzymes (EE) produced by bacteria and fungi. Extracellular enzymes convert macromolecules to simple compounds such as labile organic carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) that can be easily taken up by microbes and plants. Therefore, the enzymatic approach is helpful to understand the decomposition rates of OM and nutrient cycling in wetland soils. This paper reviews the physical and biogeochemical factors that regulate extracellular enzyme activities (EEa) in wetland soils, including those of ${\beta}$-glucosidase, ${\beta}$-N-acetylglucosaminidase, phosphatase, arylsulfatase, and phenol oxidase that decompose organic matter and release C, N, P, and S nutrients for microbial and plant growths. Effects of pH, water table, and particle size of OM on EEa were not significantly different among sites, whereas the influence of temperature on EEa varied depending on microbial acclimation to extreme temperatures. Addition of C, N, or P affected EEa differently depending on the nutrient state, C:N ratio, limiting factors, and types of enzymes of wetland soils. Substrate quality influenced EEa more significantly than did other factors. Also, drainage of wetland and increased temperature due to global climate change can stimulate phenol oxidase activity, and anthropogenic N deposition can enhance the hydrolytic EEa; these effects increase OM decomposition rates and emissions of $CO_2$ and $CH_4$ from wetland systems. The researches on the relationship between microbial structures and EE functions, and environmental factors controlling EEa can be helpful to manipulate wetland ecosystems for treating pollutants and to monitor wetland ecosystem services.

Deep Learning Framework for Watermark-Adaptive and Resolution-Adaptive Image Watermarking (워터마크 및 해상도 적응적인 영상 워터마킹을 위한 딥 러닝 프레임워크)

  • Lee, Jae-Eun;Seo, Young-Ho;Kim, Dong-Wook
    • Journal of Broadcast Engineering
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    • v.25 no.2
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    • pp.166-175
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    • 2020
  • Recently, application fields for processing and using digital image contents in various forms and types are rapidly increasing. Since image content is high value-added content, the intellectual property rights of this content must be protected in order to activate the production and use of the digital image content. In this paper, we propose a deep learning based watermark embedding and extraction network. The proposed method is to maximize the robustness of the watermark against malicious/non-malicious attacks while preserving the invisibility of the host image. This network consists of a preprocessing network that changes the watermark to have the same resolution as the host image, a watermark embedding network that embeds watermark data while maintaining the resolution of the host image by three-dimensionally concatenating the changed host image and the watermark information, and a watermark extraction network that reduces the resolution and extracts watermarks. This network verifies the invisibility and robustness of the proposed method by experimenting with various pixel value change attacks and geometric attacks against various watermark data and host images with various resolutions, and shows that this method is universal and practical.

A New Receptor for site Clonidine in the Eel, Anguilla japonica Intestine (뱀장어(Anguilla japonica)장의 상피세포막에 존재하는 새로운 clonidine 결합 수용체에 관한 연구)

  • Kim, Hung-Tae;Seo, Jung-Soo;Park, Nam-Gyu;Lee, Hyung-Ho;Chung, Joon-Ki
    • Journal of fish pathology
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    • v.14 no.1
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    • pp.31-36
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    • 2001
  • A novel clonidine binding sites were characterized in the intestinal membrane isolated from seawater eels, Anguilla japonica. The specific clonidine binding sites consisted of at least two classes, high affinity ($K_d=1.4{\pm}0.3$ nM n = 5) and low affinity ($K_d=175{\pm}34$ nM n = 5) sites. The specific binding of 2 nM [$^3H$]clonidine was most enhanced at $20^{\circ}C$ and pH 7.5, and reversed by unlabelled clonidine. Such binding was hardly inhibited by adrenaline, yohimbine or rauwolscine, indicating that most binding sites are distinct from $\alpha_2$-adrenoceptor. The specific clonidine binding sites was inhibited by various imidazoline/guanidinium drugs, indicating existence of imidazoline/guanidinium receptive sites (IGRS) or imidazoline receptors in the eel intestine. Competition experiments revealed that rank order to displace 2 nM [$^3H$]clonidine from their binding sites was as follows : guanabenz > cirazoline = naphazoline = UK14,304 = ST587 $\geq$ clonidine $\geq$ idazoxan = RX821002 = tolazoline > ST93 = oxymetazoline = amiloride = ST91 > yohimbine = efaroxan = rauwolscine $\geq$ adrenaline = ST567 = histamine = agmatine. Although physiological role of IGRS is not clear yet even in mammalian cell/tissues, eel intestine may be a good model to elucidate how the IGRS act in the cell and to decide what is the endogenous ligand for the IGRS.

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Channel Variation Tracking based Effective Preferred BS Selection Scheme of Idle Mode Mobile device for Mobile WiMAX System (Mobile WiMAX시스템에서 채널품질 변동추적을 이용한 유휴모드 이동단말의 효율적인 선호기지국 선택 방안)

  • Lee, Kang-Gyu;Youn, Hee-Yong
    • The KIPS Transactions:PartC
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    • v.17C no.6
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    • pp.471-484
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    • 2010
  • In the wireless communication systems, the power consumption of a mobile device is very important issue due to its battery limitations. Hence most of the standards for wireless networks including a mobile WiMAX system are supporting their own power saving mode in way that a mobile device is able to reduce its energy usage while in the mode. However, those standards just define the arrangement of special time intervals, called a paging listening interval, during which the device needs to receive the paging-related control messages, and they do not specify how to effectively reduce the power in many different network environments. This means the amount of power spent by the device is very dependent on the implementations of individual device-vendors, and undesirable paging loss may happen according to the channel conditions. To reduce unnecessary power usage and the risk of paging loss, this paper proposes the effective frequency/BS selection algorithm applicable to a mobile device operating in the power saving mode, which serves the device with better BS based on the tracking for channel variation. This algorithm consists of the channel estimation phase during each paging listening interval, the tracking phase for the measured results, the frequency reselection phase based on the tracking activity, and the preferred BS reselection phase. Thus the proposed method can improve the paging performance while the device is moving in the network. Also the simulation result shows that the presented scheme is superior to other candidates in energy efficiency due to the channel-adaptive frequency/BS selection.

Anti-obesity Effects of the Water Extract from Orostachys japonicus in High-fat Diet-Fed Mice (와송추출물의 비만유발 ICR 마우스에서의 항비만 효과)

  • Lee, Kyungsun;Lee, Hyeong-Seon
    • Microbiology and Biotechnology Letters
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    • v.45 no.4
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    • pp.284-290
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    • 2017
  • We investigated the anti-obesity effects of the water extract from Orostachys japonicus in high-fat-fed mice. For the analysis, 24 mice were divided into four groups: normal (N) group, high-fat diet (HFD) group, high-fat diet supplemented with 2.5% O. japonicus (HFD-OJL) group, and high-fat diet supplemented with 5% O. japonicus (HFD-OJH) group. The body weight gain and food efficiency ratio increased with a high-fat diet, but significantly decreased in the HFD-OJ groups compared with those in the HFD group. Levels of serum triglyceride, total cholesterol, and LDL-cholesterol were significantly lower, but the HDL-cholesterol level was significantly higher in the HFD-OJH group. The adipocytes within the epididymal adipose tissue were found to have expanded in the HFD group. However, the adipocytes in the HFD-OJ groups were comparable to those of the N group. These results suggest that O. japonicus has potential as an anti-obesity agent by decreasing body weight and lowering the serum lipid levels in obese mice.

Dual BTC Image Coding technique for Full HD Display Driver (Full HD 디스플레이 드라이버를 위한 Dual BTC 영상부호화 기법)

  • Kim, Jin-Hyung;Ko, Yun-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.4
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    • pp.1-9
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    • 2012
  • LCD(Liquid Crystal Display) commonly used as an output device has a drawback of slow response time compared with CRT display. This drawback causes motion blur especially when an abrupt intensity change occurs in an image sequence as time goes on. To overcome the problem of slow response time overdriving technique has been used in TCON of LCD. In this technique, the previous frame data has to be compressed and stored in an external memory. Considering both chip size of TCON and computational complexity, AM-BTC has been applied to the 8bit HD display driver. However, the conventional method is not suitable for 10 bit Full HD because 10 bit Full HD data is much larger than that of 8 bit HD data. Being applied to 10 bit Full HD display driver, the conventional method increase cost by enlarging the external memory size of TCON or deteriorates image quality. In this paper, we propose dual BTC image coding technique for Full HD display driver that is an adaptive coding scheme according to morphological information of each sample block. Through experiments, it is verified that the proposed Dual BTC method performs better than the conventional method not only quantitatively but also qualitatively.

Optimizing Multi-way Join Query Over Data Streams (데이타 스트림에서의 다중 조인 질의 최적화 방법)

  • Park, Hong-Kyu;Lee, Won-Suk
    • Journal of KIISE:Databases
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    • v.35 no.6
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    • pp.459-468
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    • 2008
  • A data stream which is a massive unbounded sequence of data elements continuously generated at a rapid rate. Many recent research activities for emerging applications often need to deal with the data stream. Such applications can be web click monitoring, sensor data processing, network traffic analysis. telephone records and multi-media data. For this. data processing over a data stream are not performed on the stored data but performed the newly updated data with pre-registered queries, and then return a result immediately or periodically. Recently, many studies are focused on dealing with a data stream more than a stored data set. Especially. there are many researches to optimize continuous queries in order to perform them efficiently. This paper proposes a query optimization algorithm to manage continuous query which has multiple join operators(Multi-way join) over data streams. It is called by an Extended Greedy query optimization based on a greedy algorithm. It defines a join cost by a required operation to compute a join and an operation to process a result and then stores all information for computing join cost and join cost in the statistics catalog. To overcome a weak point of greedy algorithm which has poor performance, the algorithm selects the set of operators with a small lay, instead of operator with the smallest cost. The set is influenced the accuracy and execution time of the algorithm and can be controlled adaptively by two user-defined values. Experiment results illustrate the performance of the EGA algorithm in various stream environments.

A Study for Real-Time Information Service (실시간 교통정보 제공에 관한 연구)

  • 김수희
    • Proceedings of the KOR-KST Conference
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    • 1998.10a
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    • pp.151-160
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    • 1998
  • 실시간 교통정보 처리과정은 현장설비로부터 수집되는 각종 교통상황자료를 분석/처리하여 소통상황, 주행속도, 통행시간 등의 교통상황을 단기 예측하는 과정으로서 이는 주행안내시스템의 핵심요소기술이다. 주행안내 시스템 개발의 필요성은 선진국을 중심으로 제기되어 왔으며, 주행안내시스템은 각국 정부의 강력한 지원정책을 바탕으로 연구개발 단계를 거쳐 시범운영의 단계에 있다. 국내에서도 교통정체의 해소와 안전주행의 연구개발 단계를 거쳐 시범운영의 단계에 있다. 국내에서도 교통정체의 해소와 안전주행의 여건마련을 위하여 교통정보를·처리·제공하는 기술의 개발이 활발하게 진행되고 있다. 그러나 국내 기술수준을 보면 전자통신기술을 바탕으로 교통정보의 수집과 제공에 관한 연구는 어느 정도 진행되고 있으나 운전자가 필요로 하는 교통정보의 분석과 처리에 관한 연구는 매우 저조한 실정이다. 본 연구의 목적은 다양한 시스템에서 수집되는 자료를 종합적으로 처리, 저장,관리하고 이의 분석결과를 제공하는 교통정보센터의 프로토타입(Prototype)을 설정하는 것이다. 이러한 목표를 수행하기 위해서 요구되는 교통정보실험실의 기능은 수집된 교통자료의 신뢰성 분석, 교통정보의 종합적인 처리·저장·관리, 그리고 교통정보의 제공은 구분할 수 있다. 따라서, 현재 교통정보실험실에서 운영중인 정보의 형태를 제시하며, 이들 정보의 신뢰성을 실측자료와 비교한 실험적 결과를 예시한다. 또한, 개별 정보이용자에게 실시간 교통정보를 제공하기 위한 통신기술의 검토가 이루어진다. 차내 이용자에게 정보를 실시간으로 제공하기 위해서는 궁극적으로 무선통신기술의 응용이 필요하며, 정보이용자에게 다양한 정보를 제공하기 위해서 인터넷 통신과 연계시키는 것이 합리적으로 판단된다. 결론 부분에서는 교통정보실험실의 기능을 강화시키기 위한 향후의 연구과제를 제시한다.Si결정의 크기를 비교하였을 때 45$\mu\textrm{m}$ 이하의 분말을 섞어 압출하였을 때 가장 작은 초정 Si입자 크기를 얻음 을 볼 수 있었다. 주의 Fairfax County에 소재한 주간 고속도로 66번(I-66)과 인접 교통망의 교통자료를 사용하여 각종 돌발교통 혼잡 상황을 전제로 한 Traffic Simulation과 정보제공시나\리오를 INTEGRATION Model을 이용해 실행하였다. 그 결과 적응형 알고리즘이 개개인의 최단시간 경로를 제공하는 사용자 평형 경로안내전략에 비해 교통혼잡도와 정체시간의 체류정도에 따라 3%에서 10%까지 전체통행시간을 절약할 수 있다는 결론을 얻었다.출발참, 구성대외개방선면축심, 실현국제항선적함접화국내항반적전항, 형성다축심복사식항선망; 가강기장건설, 개피포동제이국제기장건설, 괄응포동개발경제발전적수요. 부화개시일은 각 5월 26일과 5월 22일이었다. 11. 6월 중순에 애벌레를 대상으로 처리한 Phenthoate EC가 96.38%의 방제가로 약효가 가장 우수하였고 3월중순 및 4월중순 월동후 암컷을 대상으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as com

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