• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2628-2633
• /
• 2009

In a double deflector employed microcolumn, the variation of FOV and scan field width was investigated in mode of conversely biased double deflector to eliminate barrel distortion caused by aberration. The relationship between biased voltage of each deflector and electron emission tip voltage was studied for the maximum FOV and scan field width. The limitation and the linearity of zooming current image are also estimated as a function of electron emission tip voltage.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.2353-2355
• /
• 2010

Since the efforts in transportation for counteracting Climate Change have been enhanced, it is necessary to reduce GHG emissions from railroad construction. The aim of this study was to develop the calculation method of GHG emissions at the step of railroad construction. Main emission source was the energy consumption from the used heavy equipments. Firstly, GHG inventory including equipments list, energy consumption, and work load was established with the detailed process using standard for the unit cost of construction. Also, the energy consumption of heavy equipments during track construction at A site was collected to compare with the field data. As a result, the GHG emissions between the estimated and the field were a little different, which was caused by the inaccurate field data. Therefore, it is important to manage data efficiently for the calculation of GHG emissions in the field of railroad construction.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.662-664
• /
• 1997

3-dimensional finite element method(FEM) electrical field analysis was performed to obtain electric fields on a field emission device tip in an array form. The simulation was performed by applying the Neumann boundary condition to the intermediate plane between tips. To verify our algorithm, comparison between simulation results and experimental data from another paper was made and the difference was discussed. Finally, analysis on triode structure was performed.

• Journal of Mechanical Science and Technology
• /
• v.15 no.9
• /
• pp.1319-1327
• /
• 2001

The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed 1:1 scale. The model experiments were executed at a lower pressure than that in a real gas turbine. Combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure and NOx emission were measured at partial and full loads for both model and on-site testing. The comparison of these items in the stand and field test results led to has the development of a method of calculation and the improvement of gas turbine combustors.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.655-657
• /
• 2002

The carbon nanotube emitters for field emission displays were fabricated by screen printing techniques. The pastes for screen printing are composed of organic binders, carbon nanotubes, and some additive materials. Then the pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. From the I-V characteristics, the turn-on field of SWNT was lower than that of MWNT. The decrease in the mesh size of screen masks resulted in decreasing the turn-on field and increasing the electron emission current. When the carbon nanotubes were mixed with glass frit, glass frit appeared to contribute to the vertically aligning of carbon nanotubes on glass.

• Applied Microscopy
• /
• v.46 no.3
• /
• pp.155-159
• /
• 2016

This paper analyses the relationship between the distribution of a dielectric layer on the apex of a metal field electron emitter and the distribution of electron emission. Emitters were prepared by coating a tungsten emitter with a layer of epoxylite resin. A high-resolution scanning electron microscope was used to monitor the emitter profile and measure the coating thickness. Field electron microscope studies of the emission current distribution from these composite emitters (Tungsten-Clark Electromedical Instruments Epoxylite resin [Tungsten/CEI-resin emitter]) have been carried out. Two forms of image have been observed: bright single-spot images, thought to be associated with a smooth substrate and a uniform dielectric layer; and multi-spot images, though to be associated with irregularity in the substrate or the dielectric layer.

• Journal of The Korean Astronomical Society
• /
• v.37 no.4
• /
• pp.179-184
• /
• 2004

We have developed a wide-field imaging camera system, called WICZO, to monitor light of the night sky over extended period. Such monitoring is necessary for studying the morphology of interplanetary dust cloud and also the time and spatial variations of airglow emission. The system consists of an electric cooler a CCD camera with $60\%$ quantum efficiency at 500nm, and a fish-eye lens with $180^{\circ}$ field of view. Wide field imaging is highly desired in light of the night sky observations in general, because the zodiacal light and the airglow emission extend over the entire sky. This paper illustrates the design of WICZO, reports the result of its laboratory performance test, and presents the first night sky image, which was taken, under collaboration with Byulmaro Observatory, on top of Mt. Bongrae at Yongweol in January, 2004.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2000.01a
• /
• pp.141-142
• /
• 2000

In order to improve electron field emission and its stability, tip surface of amorphous silicon field emitters have been coated with molybdenum layer with a thickness of 25 nm through the gate opening and annealed rapidly in inert ambient. Compared with amorphous silicon field emitters, Mo silicidized amorphous silicon field emitters exhibited lower turn on voltage about 9 V, 3.8 times higher maximum current, 3.1 times lower fluctuation range and less change of the emission current depending on the vacuum level.

• 한국연소학회:학술대회논문집
• /
• 2013.06a
• /
• pp.107-108
• /
• 2013

An experimental study in the dual swirl burner was conducted to analyze the temperature characteristics in the combustion field. The dual swirl burner consists of a main swirling pre-mixed flame with tangential swirler surrounding a pilot which can stabilize a diffusion flame or a partially premixed flame with vane swirler depending on whether fuel is supplied at the exit plane or further upstream. The purpose of this study is to analyse experimentally the characterization of flame temperature in the reacting zone, specially, according to the various combustor diameters like 80mm, 100mm, 130mm and 150mm(O.D). As a result, the temperatures of combustion field were decreased as the diameter of combustor increased. Therefore, these results can be expected that the larger diameter of combustor tend to emit less NOx emission than the small combustor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.76-79
• /
• 2003

The characteristic of single wall carbon nanotube (SW-CNT) and herringbone nano fiber (HB-CNF) emitters was described. SW-CNT synthesized by arc discharge and HB-CNF prepared by thermal CVD were mixed with binders and conductive materials, and then were formed by screen-printing process. In order to obtain efficient field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNT and CNF emitters. The basic structure of FED was of a diode type through fully vacuum packaging. Also, we proposed a new triode type of field emitter using a mesh gate plate having tapered holes and could achieve the ideal triode properties with no gate leakage currents.