• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1096-1099
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• 2005

Multi-walled carbon nanotubes (CNTs) grown on catalyst dots by thermal chemical vapor deposition were vertically aligned with a high population density. Such densely populated CNTs showed poor field emission characteristics due to the electrical screening effect. We reduced the number density of CNTs using an adhesive tape treatment. For dotpatterned CNTs, the tape treatment decreased the CNT density by three orders of magnitude, drastically improved the turn-on electric field from 4.8 to $1.8V/{\mu}m$, and changed the emission image from spotty to uniform luminescence. We also report long-term emission stability of dot-patterned CNTs by measuring the emission currents with time at different duty ratios.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.588-595
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• 2020

Prediction and control of nitrogen oxides (NO_x) emission is of great interest in industry due to stricter environmental regulations. Herein, we propose an artificial intelligence (AI)-based framework for prediction of NO_x emission. The framework includes pre-processing of data for training of neural networks and evaluation of the AI-based models. In this work, Long-Short-Term Memory (LSTM), one of the recurrent neural networks, was adopted to reflect the time series characteristics of NO_x emissions. A decision tree was used to determine a time window of LSTM prior to training of the network. The neural network was trained with operational data from a heating furnace. The optimal model was obtained by optimizing hyper-parameters. The LSTM model provided a reliable prediction of NO_x emission for both training and test data, showing an accuracy of 93% or more. The application of the proposed AI-based framework will provide new opportunities for predicting the emission of various air pollutants with time series characteristics.

• Journal of Energy Engineering
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• v.16 no.1 s.49
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• pp.22-31
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• 2007

This paper addresses methodology in order to consider CHP (Combined Heat and Power) capacity in the Basic Plan of Long Term Electricity Supply & Demand and presents effects on it. The method performs state in extent that do not change maximum in the Basic Plan of Long Term Electricity Supply & Demand. For analysis that occurs some advantage this method compares with Basic Plan of Long Term Electricity Supply & Demand. It includes EES (Expected Energy Served), Fuel consumption, amount of $CO_{2}$ emission reduction.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.124-127
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• 2000

A new triode type Ti-silicided Si FEA(field emitter array) was realized by Ti-silicidation of Ti coated Si FEA and its field emission properties were investigated. In the fabricated device, the field emission properties through the unit pixel with $200{\mu\textrm{m}}{\times}200{$\mu\textrm{m}}$ tip array in the area of $1000{\mu\textrm{m}}{\times}1000{$\mu\textrm{m}}$ were as follows : the turn-on voltage was about 70V under high vacuum condition of $10^8Torr$, and the field emission current and steady state current degradation were about 2nA/tip and 0.3%/min under the bias of $V_A=500V\;and\;V_G=150V$. The low turn-on voltage and the high current stability during long term operation of the Ti silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.301-304
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• 2000

A new triode type Co-silicided Si FEA(field emitter array) was realized by Co-silicidation of Co coated Si FEA and its field emission properties were investigated. The field emission properties of the fabricated device through the unit pixel with $45{\times}45$ tip array in the area of $250{\mu\textrm{m}}{\times}250{\mu\textrm{m}}$ under high vacuum condition of $10^{-8}Torr$ were as follows : the turn-on voltage was about 35V and the anode current was about $1.2\mu\textrm{A}(0.6㎁/tip)$ at the bias of $V_A=500V\;and\; V_G=55V$. The fabricated device showed the stable electrical characteristics without degradation of field emission current for the long term operation except for the initial transient state. The low turn-on voltage and the high current stability of the Co-silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.11-21
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• 2015

The method to replace asphalt and cement is needed to reduce the carbon emission on road. Polymeric material which is light and easy to handle while having complex function with less carbon emission would be highly effective when it replaced soil pavement containing cement. This study is intended to identify the usability of soil pavement containing organic solidification agent only through the field test. Pavement on bike trail still satisfied required bearing capacity coefficient in 3 months. Pavement after passing 1.6 bil units of bike through pavement acceleration test that simulated a long-term serviceability during a short-time still remained unaffected, demonstrating a long-term serviceability of soil pavement.

• Korean Membrane Journal
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• v.6 no.1
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• pp.55-60
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• 2004

In recent years, an increasing interest in membrane technology has been observed in chemical and environmental industry. Membrane technology has advantages of low cost, energy saving and environmental clean technology comparing to conventional separation processes. Pervaporation is one of new advanced membrane technology applied for separation of azeotropic mixtures, aqueous organic mixtures, organic solvent and petrochemical mixtures. Sodium alginate composite membranes were prepared for the enhancement of long-term stability of pervaporation performance of water-ethanol mixture using pervaporation. Sodium alginate membranes were crosslinked with CaCl$_2$ and coated with polyelectrolyte chitosan to protect washing out of calcium ions from the polymer. The surface structures of PAN and hydrolysed PAN membrane were confirmed by ATR Fourier transform infrared (FT-IR). A field emission scanning electron microscopy (FE-SEM; Jeol 6340F) operated at 15 kV. Concentration profiles for Ca in the membrane surface and membrane cross-section were taken by an energy dispersive X-ray (EDX) analyser (Jeol) attached to the field emission scanning electron microscopy (Jeol 6340F). Pervaporation experiments were done with several operation run times to investigate long-term stability of the membranes.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1408-1409
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• 2011

Carbon nanotubes (CNTs) were grown on conical tip substrates by using various methods such as electrophoretic deposition, dip-coating, and spray. The scanning electron microscope measurement showed that the spray method ascertained the most uniform deposition of CNTs. The CNT-emitter that was fabricated by the spray method revealed the lowest turn on voltage of electron emission and the highest emission current. In addition, the spray-produced CNT emitter showed the most stable long-term emission characteristics.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.46-48
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• 2006

WASP which is used to plan generation expansion has disadvantages that can't manage environmental factors and regional supply-demand planning. But with the effectuation of the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol, it is expected that reducing greenhouse gases affects power system in its long-term generation expansion planning. Therefore national countermeasures is needed. This paper formulates a mathematical model considering CO2 emission constraints and Emission Trading that will be enforced. This model is based on the ORIRES which was made by ESI, Russia and manages generation expansion planning. And this mathematical model is verified by studying a case system.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.67-72
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• 2000

Demand for now nondestructive evaluation are growing to detect fatigue crack growth behavior to predict long term performance of materials and structure in aggressive environments especially when they are In non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we analysed acoustic emission signals obtained in fatigue and tensile test of high strength fire resistance steel for frame structure with time-frequency analysis methods. The main frequency range is different in the noise and the fatigue crack propagation. It could be classified that it were also generated by composite fracture mechanics of cleavage, dimple, inclusion separation etc.