• 한국기후변화학회지
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• 제7권4호
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• pp.443-450
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• 2016

The major greenhouse gases (GHGs) in agricultural sector are methane ($CH_4$), nitrous oxide ($N_2O$), carbon dioxide ($CO_2$). GHGs emissions are estimated by pertinent source category in a guideline book from Intergovernmental Panel on Climate Change (IPCC) such as methane from rice paddy, nitrous oxide from agricultural soil and crop residue burning. The methods for estimation GHGs emissions in agricultural sector are based on 1996 and 2006 IPCC guideline, 2000 and 2003 Good Practice Guidance. In general, GHG emissions were calculated by multiplying the activity data by emission factor. The total GHGs emission is $10,863Gg\;CO_2-eq$. from crop cultivation in agricultural sector in 2013. The emission is divided by the ratio of greenhouse gases that methane and nitrous oxide are 64% and 34%, respectively. Each gas emission according to the source categories is $7,000Gg\;CO_2-eq$. from rice paddy field, $3,897Gg\;CO_2-eq$. from agricultural soil, and $21Gg\;CO_2-eq$. from field burning, respectively. The GHGs emission in agricultural sector had been gradually decreased from 1990 to 2013 because of the reduction of cultivation. In order to compare with indirect emissions from agricultural soil, each emission was calculated using IPCC default factors (D) and country specific emission factors (CS). Nitrous oxide emission by CS applied in indirect emission, as nitrogen leaching and run off, was lower about 50% than that by D.

• 한국환경농학회지
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• 제38권4호
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• pp.237-244
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• 2019

BACKGROUND: Impact of incorporating hairy vetch into soil on mitigating nitrous oxide (N₂O) emissions from maize field in South Korea has not been investigated, whereas impacts on soil properties and nutrients for crops have been investigated. Therefore, this study was conducted to examine N₂O emission from upland soil incorporated with hairy vetch for one year in maize field. METHODS AND RESULTS: Hairy vetch was grown in an upland soil from November, 2017 to May, 2018 and incorporated into soil on May 25 of 2018. Control and conventional treatment (NPK) were included for comparison. Gas samples were collected weekly for a year to examine N₂O emissions from the soil. Chemical nitrogen (N) fertilizer stimulated N₂O emission in short term resulting in the greatest cumulative N₂O emission in NPK (6.72 kg N₂O ha^-1) compared to the control (4.04 kg N₂O ha^-1) and hairy vetch-incorporated field (5.43 kg N₂O ha^-1), and the greatest yield of maize from NPK, because total N input was much greater by NPK (186 N kg ha^-1) than by hairy vetch (81.6 N kg ha^-1). CONCLUSION: Incorporation of hairy vetch reduced N₂O emissions from the maize compared to the NPK-treated field. However, further research on improving crop productivity with incorporation of hairy vetch is needed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.211-211
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• 2000

Carbon nanotubes (CNTs) have been spotlighted as one of promising field emission displays(FEDs). For the first time, to authors knowledge, we have developed the 9" color CNT-FEDs with the resolution of 240x576 lines. The 9" CNT-FEDs with diode-type and triode-type structures are presented. The well-dispersed CNT paste was squeezed onto the metal-patterned cathode glass. For the anode plate, the Y2O2S:Eu, ZnS:Ag,Cl low-voltage phosphors were printed for red, green, and blue colors, respectively. The vacuum-packaged panel maintained the vacuum level of 1x10-7 Torr. The uniform moving images vacuum-packaged panel maintained the vacuum level of 1x10-7 Torr. The uniform moving images were demonstrated at 2 V/um. High brightness of 800, 200, and 150cd/m2 was observed on the green, red, and blue phosphors at V/um, respectively. Field emission characteristics of a triode-type CNT-FED were simulated using a finite element method. the resultant field strength on the cathode was modulated by gate bias and emitted electrons were focused on the anode. A relatively uniform emission image was experimentally achieved at the 800V anode. A relatively uniform emission image was experimentally achieved at the 800V anode and the 50-180 V gate biases. Energy distribution of electrons emitted from CNTs was measured using an energy analyzer. The maximum peak of energy curve corresponded to the Fermi energy level of CNTs. The whole fabrication processed of CNT-FEDs were fully scalable and reproducible. Our CNT-FEDs has demonstrated the high potential of large-area and full-color applications with very low cost fabrication and low power consumption.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.468-470
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• 2004

CNT pastes with different inorganic binder such as glass frit and spin on glass (SOG) were synthesized by using multi-walled nanotube (MWNT) grown by CVD. The uniformity of cathode layer after firing was enhanced and the emission current density at an applied field of 7.95V/${\mu}m$ increased from 133${\mu}A$/$cm^2$ to 265${\mu}A$/$cm^2$ when inorganic binder changed from glass frit to SOG. The emission properties of CNT pastes with SOG were stable and uniform although firing was carried out at relatively high temperature of 450$^{\circ}C$ under air. It is concluded that SOG is more suitable inorganic binder than glass frit for field emission application.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.647-650
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• 2002

A lateral type GaN field emission diodes were fabricated by utilizing metal organic chemical vapor deposition (MOCVD). In forming the pattern, two kinds of procedures were proposed: a selective etching method with electron cyclotron resonance-reactive ion etching (ECR-RIE) or a simple selective growth by utilizing $Si_3N_4$ film as masking layer. The fabricated device using the ECR-RIE exhibited electrical characteristics such as a turn-on voltage of 35 V for 7 ${\mu}m$ gap and an emission current of ${\sim}580$ nA/10tips at anode-to-cathode voltage of 100 V These new field emission characteristics of GaN tips are believed to be due to a low electron affinity as well as the shorter inter-electrode distance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.576-576
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• 2012

High quality single crystalline strain controlled wurtzite ZnO nanowire arrays have been grown on conductive silicon and ITO substrates by a facile hydrothermal method. The diameter of the nanowires was found to be less than 90 nm approximately for both of the two kinds of substrates. The quality of the ZnO nanowire arrays is dramatically improved by hanging the substrate above from the bottom of the Teflon lined autoclave. The structural investigation indicates the preferential orientation of the nanowire along c-axis. In order to make the convincible comparison, the photoluminescence property of the nanowire arrays grown under different conditions are measured, the sharp near band edge emission from PL, low turn-on voltage ($1.9V/{\mu}m$) from field emission measurement and Fowler-Nordheim plot was investigated from ZnO nanowire arrays grown by proposed substrate hanging method.

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.508-516
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• 1998

Mo-tip field emitter arrays(FEAs) were fabricated by conventional Spindt process and their life time characteristics and failure mode were evaluated. The fabricated Mo-tip FEA could generate at least $0.35\{mu} A/tip$ emission current for about 320 persistently under a constant gate bias of 140 V and was finally destroyed through self-healing mode. Thin diamond-like carbon films were coated on the M-tip by plasma-enhanced CVD and the dependence of emission properties upon the DLC thickness was investigated. By DLC coating, the turn-on voltage and emission current were appeared to be improved whereas the current fluctuation was increased in the DLC thickness range of $0~1,000\{AA}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1271-1272
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• 2007

Experimental results regarding to the structural properties of carbon nanotubes (CNTs) and the field-emission characteristics of CNT-coated tungsten (W) tips are presented. CNTs are successfully grown on conical-type W-tips by inductively coupled plasma-chemical vapor deposition (ICP-CVD) with or without inserting a TiN-buffer layer prior to the formation of Ni catalysts. For all the CNTs grown, their nanostructures, morphologies, and crystalline structures are analyzed by FESEM, HRTEM, and Raman spectroscopy. Furthermore, the emission properties of CNT-based field-emitters are characterized to estimate the maximum current density and the threshold voltage. The results obtained in this study indicate that the emission current level of the CNT-emitter without using a TiN buffer is desirable for the application of micro-focused x-ray systems.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1698-1702
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• 2018

We simulate the light transmission through an extremely small nanoscale aperture having a 10 nm diameter punctured in a metal film positioned at the center of a plasmonic bull's eye grating. A considerable directive emission of transmitted light with a divergence angle of 5.7 degrees was observed at $10{\mu}m$ from the nanohole opening at the frequency of surface plasmon polariton excitation, an confirmed by measuring the distance dependent transmission amplitude. Observations of the electric field in cross-sectional, near-field, and far-field views near-field enhancement associated with the surface plasmon excitation, and the interference of the electric field light through the nanohole in the near-field region is responsible for such a considerable directive emission.

• 한국진공학회지
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• 제8권1호
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• pp.36-42
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• 1999

이온빔 스퍼터링 방법으로 n-type si 기판에 고팅된, 수소를 함유하지 않은 다이아몬드성 카본 필름의 전계 방출 특성을 조사하였다. 필름의 구조나 두께에 관계없이 전계 방출 전류는 양극과 시편의 표면사이에서 발생하는 electrical breakdown에 의해 현저히 증가하였으며, 이때의 effective work function은 약 0.1eV의 작은 값을 가지고 있었다. 텅스텐 tip을 이용하여 breakdown에 의해 발생한 시편표면의 손상수위 근처를 scanning 하면서 전계 방출 전류를 측정하여, 전계 방출이 일어나는 정확한 위치를 확인하였다. 전계 방출은 breakdown에 의해 발생한 표면 손상 부위의 모든 곳에서 균일하게 일어나는 것이 아니라 특정 부위에서 집중적으로 관찰되었다. Auger electron spectroscopy와 SEM을 이용한 분석을 통해 손상 부위 중 Si과 C의 화합물이 형성된 곳에서만 절계 방출이 일어나고 있음을 알 수 있었으며, 손상부위의 형상변화는 전계 방출의 충분조건이 아니었다. 본 연구의 결과는 breakdown에 의한 전기 방출 전류의 증가는 시편 표면의 형상 변화에 의한 전계증진의 효과보다는 표면에서 발생하는 화학적 결합의 변화에 기인하고 있음을 보여준다.