• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.773-776
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• 2005

In the fabrication of high performance Blue organic light emitting diode, 2-TNATA[4,4',4"-tris(2-naphthylphenyl-phenylamino)-triphenylamine] as hole injection material and NPB[N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] as hole transport material were deposited on the ITO (Indium Tin Oxide)/Glass substrate by vacuum evaporation. And then, Blue color emission layer was deposited using GDI602 as a host material and GDI691 as a dopant. Finally, small molecule OLED with the structure of ITO/2-TNATA/NPB/GDI602+GDI691/Alq3/LiF/Al was obtained by in-situ deposition of Alq3, LiF and Al as electron transport material, electron injection material and cathode, respectively. Blue OLED fabricated in our experiments showed the color coordinate of CIE(0.14, 0.16) and the maximum luminescence efficiency of 1.06 lm/W at 11 V with the peak emission wavelength of 464 nm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2262-2267
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• 2010

In order to analyze the reason of wall blackening, which affect the decline of lifetime in a ceramic metal halide lamp, we carried out the deterioration of ceramic tubes by a change in operating conditions with arc tubes of two types of spherical and cylindrical, and we have confirmed the cause of wall blackening through the analysis of element composition and spectrum from SEM/EDS and spectrum analyzer. Wall blackening of tungsten was shown by sputtering from ignition in 20 minute on/off condition and wall blackening from chemical reaction between PCA wall and rare earth halides was shown significantly in a condition without on/off test. Especially, the wall blackening and the decline of luminous flux were reduced by inner convection in spherical type arc tube. Moreover, the color temperature and color coordinate were changed by reduction of emission spectrum of Dy which causes the chemical reaction with PCA wall.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.211-221
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• 2018

To estimate the recycling feasibility of high melt-indexed polycarbonate, 3.5 inch LGP, tensile, flexural and impact specimens were injection-molded and the LGP was shredded into scraps. The scraps were injection-molded again and this process was repeated for 4 times. Properties of the sample, i.e., optical properties, mechanical properties and number average molecular weight were measured at each cycle. Based on the results, as the number of reprocessing increased, transmittance decreased at low wavelength and color coordinate was changed systematically to yellow. Yellow index increased more than twofold during 4 recycling processes. On the other hand, the number average molecular weight decreased during recycling processes. Flexural and impact strength showed no tendency according to the number of recycling, but tensile strength decreased sharply after the third recycling process. Based on these properties, it was concluded that the number of recycling for high melt-indexed polycarbonate allowed in this study was one.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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• pp.618-632
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• 2010

This paper presents a novel approach to control the augmented reality (AR) objects robustly in a marker-less AR system by fingertip tracking and hand pattern recognition. It is known that one of the promising ways to develop a marker-less AR system is using human's body such as hand or face for replacing traditional fiducial markers. This paper introduces a real-time method to manipulate the overlaid virtual objects dynamically in a marker-less AR system using both hands with a single camera. The left bare hand is considered as a virtual marker in the marker-less AR system and the right hand is used as a hand mouse. To build the marker-less system, we utilize a skin-color model for hand shape detection and curvature-based fingertip detection from an input video image. Using the detected fingertips the camera pose are estimated to overlay virtual objects on the hand coordinate system. In order to manipulate the virtual objects rendered on the marker-less AR system dynamically, a vision-based hand control interface, which exploits the fingertip tracking for the movement of the objects and pattern matching for the hand command initiation, is developed. From the experiments, we can prove that the proposed and developed system can control the objects dynamically in a convenient fashion.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.2
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• pp.103-113
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• 1991

The accuracy of input coordinates of ground control points and check points affects great influences to the results of ground coordinate computation in using SPOT digital image data. The original SPOT images displayed on CRT are not usually adequate for identifying the object features and determining the point positioning. Hence, appropriate image processing techniques such as contrast enhancement, subpixel interpolation, edge enhancement, and spatial filtering are needed. In this study, the principles of digital image processing needed for accurate three dimensional positioning and spectral characteristic analysis are investigated. The algorithms for the actual applications are developed and programmed. And using the developed image processing software, some SPOT P-mode and XS-mode images are merged into the SPOT P＋XS, the high-resolution color composite image.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.189-196
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• 2014

Water dispersible ZnS based nanocrystals: ZnS (blue), ZnS:Cu (green) and ZnS:Mn (yellow-orange) were synthesized by capping the surface of the nanocrystals with a mercaptopropionic acid (MPA) molecule. The MPA capped ZnS based nanocrystal powders were characterized by using XRD, HR-TEM, EDXS, FT-IR, and FT-Raman spectroscopy. The optical properties of the colloidal nanocrystals were also measured by UV/Vis and photoluminescence (PL) spectroscopies in aqueous solvents. The PL spectra showed broad emission peaks at 440 nm (ZnS), 510 nm (ZnS:Cu) and 600 nm (ZnS:Mn), with relative PL efficiencies in the range of 4.38% to 7.20% compared to a reference organic dye. The measured average particle sizes from the HR-TEM images were in the range of 4.5 to 5.0 nm. White light emission was obtained by mixing these three nanocrystals at a molar ratio of 20 (ZnS):1 (ZnS:Cu):2 (ZnS:Mn) in water. The measured color coordinate of the white light was (0.31, 0.34) in the CIE chromaticity diagram, and the color temperature was 5527 K.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.5
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• pp.437-441
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• 2006

The red emitting OLEDs using $Alq_3$:Rubrene-GDI4234 phosphors have been fabricated and characterized . In the device fabrication, 2- TNATA [4,4',4' - tris (2- naphthylphenyl - phenylamino ) - tripheny lamine] as the hole injection material and NPB [N,N'-bis (1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] as the hole transport material were deposited on the ITO(indium tin oxide)/glass substrate by vacuum evaporation. And then, red color emissive layer was deposited using $Alq_3$ as the host material and Rubrene(5,6,11,12-tetraphenylnaphthacene)-GDI4234 as the dopants. finally, small molecule OLEDs with structure of ITO/2-TNATA/NPB/$Alq_3$:Rubrene-GDI4234/$Alq_3$/LiF/Al were obtained by in-situ deposition of $Alq_3$, LiF and Al as the electron transport material, electron injection material and cathode, respectively. Red OLEDs fabricated in our experiments showed the color coordinate of CIE(0.65, 0.35) and the maximum power efficiency of 2.1 lm/W at 7 V with the peak emission wavelength of 632 nm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.217-222
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• 2004

The white-light-emitting organic LED(OLED) with two-wavelength was fabricated using the DPVBi of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi/Rubrene/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). We analyzed the fabricated device through the changes of the DPVBi and Rubrene layer's thickness. We obtained the white-light-emitting OLED with white color light and the CIE coordinate of the device was (0.29, 0.33) at applied voltage of 13V when the thickness of DPVBi layer was 210$\AA$ and the thickness of Rubrene layer was 180$\AA$. At a current of 100㎃/$\textrm{cm}^2$, the quantum efficiency was 0.35％ and at a voltage of 20V, it was 0.405％.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.616-621
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• 2003

The white-light-emitting organic LED with two-wavelength was fabricated using blue emitting material(DPVBi) and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi(150$\AA$)/Alq$_3$:Rubrene(150$\AA$)/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). The changes of the CIE coordiante strongly depended on the doping concentration of Rubrene and the thickness of NPB layer. We obtained the white-light-emitting OLED close to the pure white color light and the CIE coordinate of the device was (0.315, 0.330) at applied voltage of 13V when the doping concentration of Rubrene was 0.5wt% and the thickness of NPB layer is 200$\AA$. At a current of 100mA/$\textrm{cm}^2$, the quantum efficiency was 0.35%.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1354-1357
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• 2015

In this paper, the designed fish robot is researched and developed for aquarium underwater robot. This paper is a study on how the outside technology merely to find the location of fish robots without specific sensor or internal devices for these fish robot. The model of the fish is designed to detect the position of the optical flow of the Robotic Fish in the Simulink through Matlab. This paper intends to recognize the shape of the tank via a video device such as a camera or camcorder using an image processing technique to identify the location of the robotic fish. Here, we are applied to the image comparing algorithm by using the average color weight algorithm method. In this, position coordinate system is used to find the position coordinates of the fish to identify the position of the Robotic fish. It was verified by the performance test of design robot.