• 제목/요약/키워드: research field

검색결과 24,978건 처리시간 0.052초

평지밭과 고랭지밭의 비점오염에 대한 분석과 비교 (Analysis and Comparison about NPS of Plane Field and Alpine Field)

  • 최용훈;원철희;서지연;신민환;양희정;임경재;최중대
    • 한국물환경학회지
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    • 제25권5호
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    • pp.682-688
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    • 2009
  • A plane field and a sloped field located at low-land plane and alpine areas, respectively, were monitored with respect to runoff, water quality and fertilizer uses from March to December, 2008. Runoff volume and Non-Point Source (NPS) loads were estimated and analyzed with respect to fertilizer uses. Total TN and TP loads from the sloped field were higher than those from plane field because of larger chemical uses in the alpine field than in the plane field. Organic matter load from plane field was higher than that from sloped field because more organic compost was applied to plane field than to sloped field. Event Mean Concentration (EMC) of measured water quality indices were relatively higher in both fields. Organic matter load per 1 mm rainfall were higher in plane field and TN and TP loads per 1 mm rainfall were higher in sloped field than those in respective comparing field. It was concluded that the type and application method of fertilizer could play an important role in the estimation of NPS pollution loads and the development of Best Management Practices (BMPs). However, it was recommended that long-term monitoring is necessary to better describe the relationship between fertilizer uses and water quality from agricultural fields because numerous natural and management factors other than fertilizer also affect runoff quality.

Multi-Functional Probe Recording: Field-Induced Recording and Near-Field Optical Readout

  • Park, Kang-Ho;Kim, Jeong-Yong;Song, Ki-Bong;Lee, Sung-Q;Kim, Jun-Ho;Kim, Eun-Kyoung
    • ETRI Journal
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    • 제26권3호
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    • pp.189-194
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    • 2004
  • We demonstrate a high-speed recording based on field-induced manipulation in combination with an optical reading of recorded bits on Au cluster films using the atomic force microscope (AFM) and the near-field scanning optical microscope (NSOM). We reproduced 50 nm-sized mounds by applying short electrical pulses to conducting tips in a non-contact mode as a writing process. The recorded marks were then optically read using bent fiber probes in a transmission mode. A strong enhancement of light transmission is attributed to the local surface plasmon excitation on the protruded dots.

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산학공동연구를 위한 기초조사 연구 (A Study of Exploration for the Educational-Industrial Joint Research Projects on Oriental Medicine)

  • 강효신;권영규;박재현;서부일;이정우
    • 대한한의학회지
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    • 제17권2호
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    • pp.58-72
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    • 1996
  • I. PURPOSE AND SIGNIFICANCE OF RESEARCH The presentation of research direction for compositive study and application of oriental medicine is urgently demanded. Since there is few investigation for the interest in basic and clinical field of oriental medicine, and we hope that compositive study and concentrative research between instruction in college and local clinics is established by this research. II. RESEARCH CONTENT ${\cdot}$ Analysis of survey in basic field of oriental medicine as instruction curriculum. ${\cdot}$ Analysis of survey in clinical field of oriental medicine as the classification of disease. III. RESULT The result of investigation shows that the most interested field is acupuncture and moxibustion in clinical field and diagnostics in basic field of oriental medicine. And oriental medicinal clinic doctors are concerned about prescription and a newly-developed techniques such as new acupuncture therapy, new machines. They hope that a study of oriental medicine in clinical field be accomplished with the special clinics as leader. According to the previous results, we can work out the foundation of compositive study and concentrative research between instruction in college and local clinics, and on this ground it is considered that we can grope for the presentation of research direction of local clinics.

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One-step liquid-phase fabrication of adhesive and protective inorganic layer for carbon nanotube field emitters

  • Jeong, Hae-Deuk;Kim, Ho-Young;Jeong, Hee-Jin;Jeong, Seung-Yol;Han, Joong-Tark;Lee, Geon-Woong
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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    • pp.43-43
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    • 2010
  • we have investigated the field emission characteristics of the CNT/TEOS hybrid thin films fabricated by a spray method. It is found that the CNT/TEOS hybrid emitters show high current density, low turn on field, and long-term emission stability compared to the CNT emitters. These efficient field emission characteristics of the CNT/TEOS hybrid emitters are attributed to the TEOS sol, acting as a protection layer of nanotube emitter by surrounding the nanotube tip as well as a binder material to enhance the adhesion of nanotube emitters to the substrate. Therefore, the CNT/TEOS hybrid emitters could be utilized as an alternative for the efficient and reliable field emitters.

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The effect of field-line twist on the dynamic nature and electric current structure of emerging magnetic field on the Sun

  • 안준모;;이환희;강지혜
    • 천문학회보
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    • 제37권1호
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    • pp.87.1-87.1
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    • 2012
  • We use three-dimensional magnetohydrodynamic simulations to investigate how the dynamic state of emerging magnetic field is related to the twist of field lines. Emergence of magnetic field is considered as one of the key physical process producing solar activity such as flares, jets, and coronal mass ejections. To understand these activities we have to know dynamic nature and electric current structure provided by emerging magnetic field. To demonstrate dynamic nature of field lines, we focus on the factors such as curvature of magnetic field line and scale height of magnetic field strength. These factors show that strong twist case forms two-part structure in which the central part is close to a force-free state while the outer marginal part is in a fairly dynamic state. For weak twist case, it still shows two-part structure but the tendency becomes weaker than strong twist case. We discuss how the curvature distribution affects the dynamic nature of emerging magnetic field. We also investigate electric current distribution provided by emerging field lines to show a possible relation between electric current structure and sigmoid observed in a preflare phase.

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Effect of Current-Aging on Field Emission from Carbon Nanotube Field Emitter Arrays

  • Kim, Ki-Seo;Ryu, Je-Hwang;Lee, Chang-Seok;Manivannan, S.;Moon, Jong-Hyun;Ahn, Jung-Sun;Jang, Jin;Park, Kyu-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.782-785
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    • 2007
  • We studied the effect of current-aging on field emission from carbon nanotubes field emitter arrays (CNT-FEAs) selectively patterned by the resist-assistan tpatterning(RAP) process. After sustaining the electric field when starting emission current density $(J_s)$ is $0.1\;mA/cm^2$ during 40 hrs, it was observed that the field emission property and uniformity were remarkably improved due to the elimination of oxygen atom and thus the reconstruction of carbon bonding at the tip of CNTs during field emission.

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감광성 탄소나노튜브 페이스트의 조성과 열처리가 전계방출 특성에 미치는 영향 (Effect of Photosensitive Carbon Nanotube Paste on Field Emission Properties)

  • 오정섭;김대준;정진우;송윤호;조영래
    • 한국재료학회지
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    • 제16권9호
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    • pp.550-556
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    • 2006
  • Photosensitive carbon nanotube (CNT) pastes are explored to develop a CNT field emitter for field emission display (FED) application. We formulated a photosensitive paste including multi-walled CNTs (MWNTs) for screen printing. The photosensitive CNT paste was synthesized by mixing of MWNTs, inorganic fillers (nano metal), organic vehicle, monomers and photo initiator. The CNT paste films were patterned by using backside exposure technique. The CNTs were strongly fixed on a cathode by formation of carbon residue during firing process. For the CNT emitters, current-voltage(I-V) characteristics and images of field emission were evaluated. The emission properties of CNT emitters are dependent on the paste composition. A turn-on electric field for the CNT field emitters is measured to be 1 V/$\mu$m. Additionally, the effect of heat treatment parameter on field emission properties was discussed. The newly formulated photosensitive CNT paste can be potentially applicable to highly reliable CNT field emitters.

Statistical study on nightside geosynchronous magnetic field responses to interplanetary shocks

  • 박종선;김관혁;;이동훈;이은상;진호
    • 천문학회보
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    • 제37권2호
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    • pp.116.1-116.1
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    • 2012
  • When an interplanetary (IP) shock passes over the Earth's magnetosphere, the geosynchronous magnetic field strength near the noon is always enhanced, while the geosynchronous magnetic field near the midnight decreases or increases. In order to understand what determines the positive or negative magnetic field response at nightside geosynchronous orbit to sudden increases in the solar wind dynamic pressure, we have examined 120 IP shock-associated sudden commencements (SC) using magnetic field data from the GOES spacecraft near the midnight (MLT = 2200~0200) and found the following magnetic field perturbation characteristics. (1) There is a strong seasonal dependence of geosynchronous magnetic field perturbations during the passage of IP shocks. That is, the SC-associated geosynchronous magnetic field near the midnight increases (a positive response) in summer and decreases (a negative response) in winter. (2) These field perturbations are dominated by the radial magnetic field component rather than the north-south magnetic field component at nightside geosynchronous orbit. (3) The magnetic elevation angles corresponding to positive and negative responses decrease and increase, respectively. These field perturbation properties can be explained by the location of the cross-tail current enhancement during SC interval with respect to geosynchronous spacecraft position.

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Effect of in-Plane Magnetic Field on Rashba Spin-Orbit Interaction

  • Choi, Won Young;Kwon, Jae Hyun;Chang, Joonyeon;Han, Suk Hee;Koo, Hyun Cheol
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.394-394
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    • 2013
  • The spin-orbit interaction has received great attention in the field of spintronics, because of its property and applicability. For instance, the spin-orbit interaction induces spin precession which is the key element of spin transistor proposed by Datta and Das, since frequency of precession can be controlled by electric field. The spin-orbit interaction is classified according to its origin, Dresselhaus and Rashba spin-orbit interaction. In particular, the Rashba spin-orbit interaction is induced by inversion asymmetry of quantum well structure and the slope of conduction band represents the strength of Rashba spin-orbit interaction. The strength of spin-orbit interaction is experimentally obtained from the Shubnikov de Hass (SdH) oscillation. The SdH oscillation is resistance change of channel for perpendicular magnetic field as a result of Zeeman spin splitting of Landau level, quantization of cyclotron motion by applied magnetic field. The frequency of oscillation is different for spin up and down due to the Rashba spin-orbit interaction. Consequently, the SdH oscillation shows the beat patterns. In many research studies, the spin-orbit interaction was treated as a tool for electrical manipulation of spin. On the other hands, it can be considered that the Rashba field, effective magnetic field induced by Rashba effect, may interact with external magnetic field. In order to investigate this issue, we utilized InAs quantum well layer, sandwiched by InGaAs/InAlAs as cladding layer. Then, the SdH oscillation was observed with tilted magnetic field in y-z plane. The y-component (longitudinal term) of applied magnetic field will interact with the Rashba field and the z-component (perpendicular term) will induce the Zeeman effect. As a result, the strength of spin-orbit interaction was increased (decreased), when applied magnetic field is parallel (anti-parallel) to the Rashba field. We found a possibility to control the spin precession with magnetic field.

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