• Journal of Information Display
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• 제2권3호
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• pp.72-77
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• 2001

Amorphous silicon thin-film transistors (a-Si TFTs) were incorporated into Mo-tip-based triode-type field emitters and diode-type ones of carbon nanotubes for an active-matrix cathode (AMC) plate of field emission displays. Also, we developed a novel surface-treatment process for the Mo-tip fabrication, which gleatly enhanced in the stability of field emission. The field emission currents of AMC plates on glass substrate were well controlled by the gate bias of a-Si TFTs. Active-matrix field emission displays (AMFEDs) with these AMC plates were demonstrated in a vacuum chamber, showing low-voltage matrix addressing, good stability and reliability of field emission, and highly uniform light emissions from the anode plate with phosphors. The optimum design of AMFEDs including a-Si TFTs and a new light shield/focusing grid is discussed.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권1호
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• pp.11-23
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• 2000

Photochemical air quality models are essential tools in predicting future air quality and assessing air pollution control strategies. To evaluate air quality using a photochemical air quality model, emission inventories are important inputs to these models. Since most emission inventories are provided at a county-level, these emission inventories need to be geographically allocated to the computational grid cells of the model prior to running the model. The conventional method for the spatial allocation of these emissions uses "spatial surrogate indicators", such as population for mobile source emissions and county area for biogenic source emissions. In order to examine the applicability of such approximations, more detailed spatial surrogate indicators were developed using Geographic Information System(GIS) tools to improve the spatial allocation of mobile and boigenic source emissions, The proposed spatial surrogate indicators appear to be more appropriate than conventional spatial surrogate indicators in allocating mobile and biogenic source emissions. However, they did not provide a substantial improvement in predicting ground-level ozone(O3) concentrations. As for the carbon monoxide(CO) concentration predictions, certain differences between the conventional and new spatial allocation methods were found, yet a detailed model performance evaluation was prevented due to a lack of sufficient observed data. The use of the developed spatial surrogate indicators led to higher O3 and CO concentration estimates in the biogenic source emission allocation than in the mobile source emission allocation.llocation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.504-505
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• 2011

Decreasing actual greenhouse gas will be difficult if it is not solved addressed in architectural fields. Zero emission building or zero energy building, maximize the efficiency of energy, which means the building can operate by their own renewable energy facility without any other supplying. To be a zero emission building, a building needs realization of high efficiency low energy consumption, construction of building its own energy production facilities and lastly a power grid connection. According to increasing of DC load about TV, LED lighting, computer, IT in building for living and business, it is expected the save of energy when the system of AC power distribution change into the system of DC power distribution. Renewable energy exists a big different rate produced by outside environment. When electrical power overproduce, it can supply for system. Otherwise, if electrical power produce less, it can receive supply from system. Send and receive power can lead to zero to annual standard. This paper shows the simulation about efficient control of power conversion which is related to DC power distribution of architecture and DC output of renewable energy by using L-type converter.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권8호
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• pp.419-422
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• 2001

This paper presents the principle and fabrication of a novel micro mass spectrometer and emission test of hot electron for ionization. A micro mass spectrometer consists of a micro ion source and a micro ion separator. The micro ion source consists of a hot filament and grid electrodes. Electrons emitted from a hot filament are to ionize some sample molecules. The ions are accelerated to an ion detector by an electric field. Mass can be analyzed by using the time of fight depending on the mass-to-charge ratio. The current of hot electron emission from the hot filament is measured for various input voltages.

• 전기학회논문지
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• 제66권7호
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• pp.1032-1038
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• 2017

Recently, regulation on carbon emissions has been strengthened according to the new climate change convention (COP21) held in Paris, and then Korea has decided to reduce CO2 emissions by 37% until 2030. As one of countermeasures, the government has energetically performed demonstration projects of island micro-grid including solar power, wind power and energy storage system. However, in order to smoothly introduce island micro-grid, it is a critical issue to carry out the economic evaluation for power utility aspect and independent power producer aspect. Therefore, this paper proposes economic evaluation algorithms of island micro-grid which are based on the present worth method, considering cost and benefit factors in the aspect of both sides. Firstly, in case of power utility this paper proposes algorithm to estimate a period of return on investment according to the introduction capacity of distributed generators replacing diesel generator. And also, in case of independent power producer, this paper proposes evaluation algorithm to estimate weighting factor of SMP and benefit rate based on break-even point related with cost and benefit. From a case study result on real island micro-grid model, it is confirmed that proposed algorithms are useful and practical for the economic evaluation of island micro-grid.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2002년도 춘계학술발표회 초록집
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• pp.46-46
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• 2002

It is well known that thin film growth and surface morphology can be substantially modified by ion-bombardment during the deposition. This is particularly important in case of thin-film deposition at low temperatures where the film growth occurs under highly nonequilibrium conditions. An attractive way to promote crystalline growth and surface morphology is deposition of additional energy in to the surface of the growing film by bombardment with hyperthermal particles. We were deposited crystalline Ti and TiN thin films on Si substrate by magnetron sputtering method with grid. Its thin films were highly smoothed and dense as increasing grid bias. In order explore the benefits of a bombardment of the growing film with high energetic particles. Ti and TiN films were deposited on Si substrates by an unbalanced magnetron sputter source with attached grid assembly for energetic ion extraction. Also, we have studied the variation of the plasma states by Langmuir probe and Optical Emission Spectroscopy (OES). The epitaxial orientation. microstructual characteristics. electrical and surface properties of the films were analyzed by XRD. SEM. Four point probe and AFM.

• 전기학회논문지
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• 제60권6호
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• pp.1280-1285
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• 2011

Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.

• 한국대기환경학회지
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• 제32권4호
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• pp.372-383
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• 2016

This study aimed at analyzing the sensitivity of ozone simulation in accordance with the meteorological nudging for a high nocturnal ozone episode. To demonstrate the effectiveness of nudging methods (e.g., nudging techniques and application domains), the following six experiments were designed: (1) control without nudging, (2) experiment with application of observation nudging to all domains (domain 1~4), and (3)~(6) experiments with application of grid nudging to domain 1, domain 1~2, domain 1~3 and all domains, respectively. As a result, the meteorological nudging had a direct (improvement of input data) and indirect (estimate natural emission) effect on ozone simulation. Nudging effects during the daytime were greater than those during the nighttime due to low accuracy of wind direction during the nighttime. On comparison of the nudging techniques, the experiments in which grid nudging was applied showed more improved results than the experiments in which observation nudging was applied. At this time point, the simulated concentrations were generally similar to the observed concentrations due to the increase in the nudging effect when grid nudging was applied up to the sub-domain. However, for high nocturnal ozone uptakes, the experiment in which grid nudging was applied do domain 1~3 showed better results than the other experiments. This is because, when grid nudging was applied to the high resolution domain (e.g., domain 4 with 1 km), the local characteristics were removed due to the smoothing effects of meteorological conditions.

• 한국기후변화학회지
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• 제7권3호
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• pp.217-229
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• 2016

Increased evidences reveal that the global climate change adversely affect on the environment. Smart grid system is one of the ways to reduce greenhouse gas emissions in the electricity generation sector. Since 2013, Korea Electric Power Corporation (KEPCO) has installed smart grid station in KEPCO office buildings. The goal of this paper is two folds. One is to quantify the reduction in greenhouse gas emissions through smart grid stations installed in KEPCO office buildings as a part of pilot project. Among components of smart grid stations, this research focused on the photovoltaic power system (PV) and energy storage system (ESS). The other is to estimate the reduction in greenhouse gas emissions when PV is applied on individual houses. Results show that greenhouse gas emissions reduce 5.8~11.3% of the emissions generated through the electricity usage after PV is applied in KEPCO office buildings. The greenhouse gas emissions reduction from ESS is not apparent. When PV of 200~500 W is installed in individual houses, annual greenhouse gas emission reduction in 2016 is expected to be approximately $2.2{\sim}5.4million\;tCO_2-eq$, equivalent to 6~15% of greenhouse gas emissions through the electricity usage in the house hold sector. The saving of annual electricity cost in the individual house through PV of 200 W and 500 W is expected to be 47~179 thous and KRW and 123~451 thousand KRW, respectively. Results analyzed in this study show the environmental effect of the smart grid station. In addition, the results can be further used as guidance in implementing similar projects.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.77-82
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• 2021

Using a multi-array needle module developed for coating of high-density cylindrical microlens array (C-MLA), we have fabricated an anti-Moiré filter for LED screens. The Moiré phenomenon appears due to the interference between the array pattern of image sensors in a camera and the non-emission area (grid pattern) of a LED screen. To suppress it, we have employed poly(methyl methacrylate) (PMMA) and coated it on a glass substrate in the form of a grid and non-grid (parallel lines). We have rotated the needle module in order to increase the number of C-MLAs. With this scheme, we have fabricated the 150 mm × 150 mm anti-Moiré filters where 836 microlens lines are formed. They show the average width of 255.4 ㎛, the average distance between CMLs of 94.6 ㎛, and C-MLA width non-uniformity of 4.7%. We have shown that the Moiré patterns still appear in the presence of the parallel (non-grid)-type filter, whereas they disappeared completely by the grid-type filter. It is due to the fact that the Moiré patterns are diffused more effectively by the grid-type C-MLA.