• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3367-3371
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• 2013

MgO nanorods were fabricated by the thermal evaporation of $Mg_3N_2$. The influence of ZnO sheathing and hydrogen plasma exposure on the photoluminescence (PL) of the MgO nanorods was studied. PL measurements of the ZnO-sheathed MgO nanorods showed two main emission bands: the near band edge emission band centered at ~380 nm and the deep level emission band centered at ~590 nm both of which are characteristic of ZnO. The near band edge emission from the ZnO-sheathed MgO nanorods was enhanced with increasing the ZnO shell layer thickness. The near band edge emission from the ZnO-sheathed MgO nanorods appeared to be enhanced further by hydrogen plasma irradiation. The underlying mechanisms for the enhancement of the NBE emission from the MgO nanorods by ZnO sheathing and hydrogen plasma exposure are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.103-106
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• 1999

In this paper, we suggest the FED packaging technology that have 4mm thickness, using sodalime glass-to-sodalime glass electrostatic bonding. It based on conventional silicon-glass bonding. The silicon film was deposited an around the exhausting hole on FED backside panel. And then, the silicon film of panel was successfully bonded with capping(bare) glass in vacuum environment and the FED panel was vacuum-sealed. In this method, we could achieve more 153 times increased conductance and 200 times increased vacuum efficiency than conventional tube packaging method. The vacuum level in panel, by SRG test, was maintained about low 10$_{-4}$ Torr during above two months And, the light emission was observed to 0.7-inch tubeless packaged FED. Then anode current was 34 $\mu$ A. Emission stability was constantly measured for 10 days.

• Journal of the Korean Society of Combustion
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• v.13 no.4
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• pp.1-7
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• 2008

Strict pollutant regulations of NOx emission and increasing awareness of the environmental damage stimulated interest in research to obtain useful information regarding CO and NOx reductions at the same time. In this study, $CH_4$/air premixed flame was examined numerically to reduce CO and NOx emission level simultaneously in the post-flame region by the heat loss models in which radiative and combined conductive and convective heat losses were included. To reduce the NOx emission, first heat exchanger location was decided near the flame. After first heat exchanger was decided for the optimal NOx emission(about 30 ppm), in order to decide the optimal CO emission(about 30ppm), seocond heat exchanger location was tested and decided for several cases. Finally, the optimal location of heat exchanger for minimal CO and NOx emission simultaneously were determined and suggested.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.326-331
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• 2000

We have fabricated the field emitter arrays coated with diamond-like carbon (DLC) films that improved the field emission characteristics. The nitrogen doped DLC films are prepared by the filtered cathodic vacuum are (FCVA) tehnique. The activation energy of the nitrogen doped DLC films are derived from electrical conductivity measurements. The silicon field emission arrays (FEAs) were prepared by the VLSI technique. The turn-on field was rapidly decreasing and the emission current was remarkably increasing the DLC-coated FEAs than the non-coated silicon FEAs. In the nitrogen doped FEAs, the turn-on field decreased and the emission current increased with increasing the nitrogen found out the field emission current and the work function of the DLC-coated FEAs was remarkably decreased than that of the non-coated silicon FEAs. As nitrogen doping concentrations are increased the work function of FEAs is decreased and the field emission properties are improved in nitrogen doped DLC-coated FEAs. This phenomenon in due the fact that the Fermi energy level moves to the conduction band by increasing nitrogen doping concentration.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.226-226
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• 2016

PHOLED devices which have the structure of ITO/HAT-CN(5nm)/NPB(50nm)/EML(30nm)/TPBi(10nm)/Alq3(20nm)/LiF(0.8nm)/Al(100nm) are fabricated to investigate the green emission profile in EML by using a gasket doping method. CBP and Ir(ppy)3 (2% wt) are co-deposited homogeneously as a background material of EML for green PHOLED, then a 5nm thickness of additionally doped layer by Ir(btp)2 (8% wt) is formed as a profiler of the green emission. The total thickness of the EML is maintained at 30nm while the distance of the profiler from the HTL/EML interface side (x) is changed in 5nm steps from 0nm to 25nm. As shown in Fig. 1, the green (513nm) peak from Ir(ppy)3 is not observed when Ir(btp)2 is also doped homogeneously because Ir(ppy)3 works as an gasket dopant of the Ir(btp)2 :CBP system. Therefore, in this experment, Ir(btp)2 can be used as a profiler of the green emission in CBP:Ir(ppy)3 system. The emission spectra from the PHOLED devices with different x are shown in Fig. 2. In this gasket doping system, stronger red peak means more energy transfer from green to red dopant or higher exciton density by green dopant. To find the green emission profile, the external quantum efficiency (EQE) at 3mA/cm2 for red peaks are calculated. More green light emission at near EML/HBL interface than that of HTL/EML is observed (insert of Fig. 2). This means that the higher exciton density at near EML/HBL interface in homogeneously doped CBP with Ir(ppy)3. As shown in Fig. 3, excitons can be quenched easily to HTL(NPB) because the T1 level of HTL(2.5eV) is relatively lower than that of EML(2.6eV). On the other hand, the T1 level of HBL(2.7eV) is higher than that of EML.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.316-326
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• 2008

The Earth's temperature has risen $0.76^{\circ}C$ (degree) during last 100 years which Implies a sudden rise, compare with the 4oC (degrees) rise through out the past 20,000 years. If the volume of GHG (Greenhouse Gas) emission continues at the current level, the average temperature of the Earth will rise by $1^{\circ}C$ (degree) by 2030 with the further implication that the temperature of Earth will rise by $2{\sim}5^{\circ}C$ (degrees) every 100 years. Therefore, as we are aware that the temperature of the glacial epoch was $8{\sim}9^{\circ}C$ (degrees) lower than the present time, we can easily predict that the above temperature rises can be potentially disastrous for human life. Every country in the world recognizes theseriousness of the current climate change and adopted a convention on climate change in June 1992 in Rio. The COP1 was held in March 1995 in Berlin and the COP3 in Dec. 1997 in Kyotowhere the target (2008-2012) was determined and the advanced nations' reduction target (5.2%, average)was also agreed at this conference. Korea participated in the GHG reduction plan which required the world's nations to ratify the Kyoto Protocol. Ratification of the Kyotoprotocol and the followup requirement to introduce an international emissions trading scheme will require severe reductions in GHGs and considerable economic consequences. USA are still refusing to fully ratify the treaty as the emission reductions could severely damage the economies of these countries. In order to estimate the exact $CO_2$ emission, this study statistically analyzed $CO_2$ emission of each country based on the following variables : level of economic power and scientific development, the industrial system, productivity and energy efficiency.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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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.

• Journal of Climate Change Research
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• v.9 no.1
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• pp.81-90
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• 2018

"The Framework Act on Low-Carbon Green Growth" specifies the requirements for the development and verification of emission factors for establishing reliable national greenhouse gas statistics. The scope of the regulations covers the development and validation of energy, industrial processes, solvents and other product use, agriculture, land use, land use change and emission and absorption coefficients of the forestry and waste sector as defined in the 1996 IPCC Guideline and GPG 2000, The minerals sector to be covered in this study belongs to industrial processes. As a representative method for quantifying and evaluating GHG emission factors, there are emission grade quality grading and DARS (Data Rating Rating System) in the 'Procedures for Preparing Emission Factor Documents (1997)' reported by US-EPA. However, the above two methods are not specific and comprehensive, and lack the details for accurate emission factor verification. Therefore, there is a need for a method for verifying and quantifying certified greenhouse gas emission factors that reflects characteristics of each industry sector in Korea and accord with IPCC G/L and GHG target management. In this study, we conducted a weighted study on quantitative and evaluation lists of emission factor using questionnaires to develop a more accurate methodology for quantifying national greenhouse gas emission factors in the mineral sector. Quantification and evaluation of emission factor are classified into essential verification and quality evaluation. The essential verifications are : administrative compatibility, method of determining emission factors, emission characteristics, sampling methods and analysis methods, representativeness of data. The quality evaluations consisted of the quality control of the data, the accuracy of the measurement and analysis, the level of uncertainty, not directly affect the emission factor, but consisted of factors that determine data quality.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.86-92
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• 2011

In order to reduce dependence on the fossil fuels and $CO_2$ gas emission in farming activities, the government has pushed ahead with making the self-sufficiency of farming energy up 40% level in green villages. The objectives of this study are to survey the energy consumption of horticultural facilities or agricultural machineries, and to analyze the reduced $CO_2$ gas emission level from fossil fuel to bio-diesel fuel. For the implement of this study, it is necessary to analyze the energy consumption level in the various sector of farming activities, and available renewable energy sources should be selected. Annual total $CO_2$ gas emission in the tillage farming sector was analyzed as $5,667,258\;t-CO_2$ and that in the horticultural facilities occupied $4,932,607\;t-CO_2$, while the $CO_2$ gas emission level of diesel fuel was $3,105,707\;t-CO_2$, and that of the heavy oil showed $1,370,578\;t-CO_2$. The average $CO_2$ gas emission level of horticultural facilities in the country was analyzed as $29,418\;t-CO_2/ha$. Among the total energy consumption of agricultural machineries, tractor used 284,763kL, power tiller spent 221,314 kL, grain drier consumed 145,524kL and combine tractor expend 72,537kL. From the comparison of $CO_2$ gas emission level between fossil fuel and bio-diesel fuel for the horticultural facilities or agricultural machinery in G-City, Jeonbuk Province, the $CO_2$ gas emission level can be reduced by 7% through replacing the fuel from fossil to biodiesel.

• Publications of The Korean Astronomical Society
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• v.1 no.1
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• pp.13-20
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• 1984

New empirical relations between stellar CaII emission and rotation or age are derived by analyzing Wilson's CaII flux measurements (1968, 1978) of lower main sequence stars, and then we correlate them with their age and rotation rate. It is found that stellar chromospheric emission decays smoothly with age as a star slows down rotationally, establishing that both the emission level and rotation rate decrease with the square root of age.