• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.473-476
• /
• 2006

Microcavity plasma devices having characteristic dimensions below $100\;{\mu}m$ have been investigated as a candidate for the next generation of plasma displays. Arrays of inverted pyramid microcavity devices, fabricated in Si with emitting apertures of $(50\;{\mu}m)^2$ and designed for AC or bipolar excitation, demonstrate a luminous efficacy above 6 lm/W at pressures up to and beyond one atmosphere of Ne/Xe mixtures. Also the design of analogous microplasma devices in ceramic multilayer structures or plastic substrates is disccussed.

• Journal of Energy Engineering
• /
• v.10 no.4
• /
• pp.379-386
• /
• 2001

This experimental study deals with on Nitric Oxide Formation & Reduction in Industrial Bunner. In this study, Laser-induced fluorescence (LIF) techniques have been used for quantitative measurements of Nitric Oxide. The NO A-X (0, 0) Vibrational band around 226 nm was excited using a XeCl excimer-pumped dye laser. And on-line excitation used $P_{21}+Q_1(14.5)/R_{12}+Q_2(20.5)/P_1(23.5)$ transition, for minimizing the other interferential effect. The measurements were taken NO concentration distribution in double swirling diffusion flame. In this swirl burner, NO concentration in downstream fo the flame decrease as primary/secondary air ratio increases.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.7-12
• /
• 2006

The high efficacy concept, featuring in this study an auxiliary electrode and a 200 ${\mu}m$ coplanar gap, is applied to AC-PDPs with a stripe - type and a closed - type barrier rib, respectively. The roles of the pulses applied to the auxiliary electrode create additional excitation during the sustain period and reduce a discharge current that flows into the display cells. The efficacy of the proposed panel with the closed barrier rib has maximum values when the auxiliary pulse voltage is 50 volts and 80 volts for the Ne+4%Xe and Ne+20%Xe gas-mixtures, respectively. The maximum luminous efficacy is more than 10 lm/W in terms of the measurement of the discharges in VGA resolution ($540{\mu}m{\times}720{\mu}m$) and the green cells.

• Korean Journal of Optics and Photonics
• /
• v.6 no.1
• /
• pp.33-38
• /
• 1995

We have measured the excited state absorption in $Ce:YAlO_{3}$, crystals for the first time and assigned it for a 5d$\rightarrow$conduction band transition. Two broad absorption bands were observed at 555 nm and 465 nm fowllowing the 308 nm XeCl laser excitation and their cross sections and oscillator strengths were calculated. We have also measured the fluorescence lifetimes in between 300 K and 700 K to study the nonradiative relaxation from the lowest 5d state of $Ce^{3+}$ ions and explained ESA and the transition process from the state in terms of a configurational coordinate.dinate.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.2
• /
• pp.72.2-72.2
• /
• 2010

The extremely metal-poor halo planetary nebula BoBn 1 has been investigated based on IUE archive data, Subaru/HDS spectra, VLT/UVES archive data, and Spitzer/IRS spectra. We have measured a heliocentric radial velocity of $+191.6\pm1.3\;kms^{-1}$ and expansion velocity 2Vexp of $40.5\pm3.3\;kms^{-1}$ from an average over 300 lines. The estimations of C, N, O, and Ne abundances from the optical recombination lines (ORLs) and Kr, Xe, and Ba from the collisional excitation lines (CELs) are also done. We have detected 5 fluorine and several slow neutron capture elements (the s-process). The amounts of [F/H], [Kr/H], and [Xe/H] suggest that BoBn 1 is the most F-rich among F detected PNe and is a heavy s-process element rich PN. The photo-ionization models built with non-LTE theoretical stellar atmospheres indicate that the progenitor was a 1-1.5 $M_\bigstar$ that would evolve into a white dwarf with an $0.62M_{\odot}$ core mass and $0.09M_{\odot}$ ionized nebula. Careful examination implies that BoBn 1 has evolved from a binary and experienced coalescence during the evolution to become a visible PN. The elemental abundances except N could be explained by a binary model composed of $0.75M_{\odot}+1.5M_{\odot}$ stars.

• Korean Journal of Materials Research
• /
• v.12 no.9
• /
• pp.735-739
• /
• 2002

$(Y,Gd)BO_3$: Eu, $Zn_2$$SiO_4$ : Mn and $BaMgAl_{10}$ $O_{17}$ : Eu phosphors used in PDP were continuously irradiated by vacuum ultra violet generated from the penning gas (96%Ar+4%Xe) discharge and then the change of emitting intensity with time was investigated. The brightness of these phosphors decreased exponentially with VUV excitation time. The experimental data showed that the degradation rate increased in the order of $Zn_2$$SiO_4$ : Mn>(Y,Gd)$BO_3$: Eu>$BaMgAl_{10}$ $O_{17}$ : Eu phosphor. This different degradation property of phosphors was interpreted in terms of brightness saturation and stability against VUV irradiation. It was found that the degradation property of $(Y,Gd)BO_3$ : Eu red phosphor synthesized by ultrasonic thermal spray was superior to commercial phosphor.

• Korean Journal of Materials Research
• /
• v.20 no.7
• /
• pp.364-369
• /
• 2010

A $SrAl_2O_4:Eu^{2+},Dy^{3+}$ phosphor powder with stuffed tridymite structure was synthesized by glycine-nitrate combustion method. The luminescence, formation process and microstructure of the phosphor powder were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The XRD patterns show that the as-synthesized $SrAl_2O_4:Eu^{2+},Dy^{3+}$ phosphor was an amorphous phase. However, a crystalline $SrAl_2O_4 $ phase was formed by calcining at $1200^{\circ}C$ for 4h. From the SEM analysis, also, it was found that the as-synthesized $SrAl_2O_4:Eu^{2+},Dy^{3+}$ phosphor was in irregular porous particles of about 50 ${\mu}m$, while the calcined phosphor was aggregated in spherical particles with radius of about 0.5 ${\mu}m$. The emission spectrum of as-synthesized $SrAl_2O_4:Eu^{2+},Dy^{3+}$ phosphor did not appear, due to the amorphous phase. However, the emission spectrum of the calcined phosphor was observed at 520 nm (2.384eV); it showed green emission peaking, in the range of 450~650 nm. The excitation spectrum of the $SrAl_2O_4:Eu^{2+},Dy^{3+}$ phosphor exhibits a maximum peak intensity at 360 nm (3.44eV) in the range of 250~480 nm. After the removal of the pulse Xe-lamp excitation (360 nm), also, the decay time for the emission spectrum was very slow, which shows the excellent longphosphorescent property of the phosphor, although the decay time decreased exponentially.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.1519-1526
• /
• 2011

A previous study (Lee, C. W. J. Phys. B 2010, 43, 175002) that isolated the overlapping resonances in the photoionization spectra using multichannel quantum defect theory (MQDT) in systems involving a single open channel was extended to manage many open channels when the closed channels are degenerate. The theory was applied to the dipole allowed J = 1$^{\circ}$ spectra from the ground state with excitation energies lying between the lowest ionization thresholds for rare gas atoms, Ar, Kr, and Xe, and also for group IV elements, Ge, Sn and Pb.

• 한국연소학회:학술대회논문집
• /
• 2001.06a
• /
• pp.133-138
• /
• 2001

In this study, quantitative nitric oxide concentration distributions are investigated in the laminar nonpremixed $H_2/N_2$ flames by laser-induced fluorescence (LIF). The measurements are taken in flames for different $N_2$ dilution ratios varying from 20${\sim}$80%, and fuel now rate is fixed as lslpm. The NO A-X (0,0) vibrational band around 226 nm is excited using a XeCl excimer-pumped dye laser. We applied same excitation line used in $CH_4$ premixed flame. Overall, NO concentration was rapidly decreased with $N_2$ addition and we could not measure the concentration any longer for $N_2$ dilution above 80%.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.33-36
• /
• 2007

We performed a discharge analysis on ac plasma display panel through the numerical simulation of the EF (Energy Fluid) model using the electron's energy equation. When it is compared to the results of commonly used LFA (Local Field Approximation) model, there is a clear difference in the spatiotemporal distribution of Xe excited species. In particular, the experimentally observed striation phenomena in the anode region could be observed in EF model and the occurrence of the striation was attributed to the ionization and excitation instability due to the streaming electrons in the anode region plasma.