Jong-Mun Jeong

X‐ray photoemission studies of W 4f core levels of electrochromic HxWO3 films

Using x‐ray photoelectron spectroscopy (XPS), W 4f core level spectra of electrochromic HxWO3 films have been investigated as a function of the injected charge. W 4f peaks become broader with increasing injected charge. The line shape analysis of W 4f XPS spectra of amorphous HxWO3 films reveals that each spin‐orbit split component consists of two peaks. It is also found that, as the injected charge increases, the intensity of the low binding energy (BE) peaks, the asymmetry factor of core lines, and the intrinsic lifetime width increase systematically. Composite structures of W 4f peaks have been attributed to the existence of the different final states, screened by different numbers of W 5d electrons. The low BE peaks are considered to correspond to the locally screened final states, with one more W 5d electrons than in the ground state, which arise from midgap state conduction electrons near EF. There is also a possibility that a mixture of fine scale phases contributes to composite structures and broa...

Glass tube of high dielectric constant and low dielectric loss for external electrode fluorescent lamps

A glass tube of aluminosilicate glass, with high dielectric constant K∼6.0 and low dielectric loss tan δ∼8.0×10−4, was investigated for the external electrode fluorescent lamps (EEFLs) of a dielectric barrier discharge. Compared with conventional EEFLs made out of borosilicate glass tubes with K∼(4.9−5.3) and tan δ∼(2.3−2.4)×10−3, the efficiency of the aluminosilicate EEFL increases by 15%−25% even at high luminance above 20 000 cd/m2 and the pinhole stability of the aluminosilicate EEFL also improves remarkably. In a soda-lime glass EEFL with a high dielectric loss tan δ∼7.0×10−3, the luminance and pinhole stability deteriorate even with a high dielectric constant K∼7.2 at room temperature, because the value of tan δ escalates as the temperature on the external electrode increases due to the dielectric heat dissipation.

Dependence of the magnetic properties of Co/Pd multilayered films on the structural parameters estimated accurately by x‐ray diffraction

In this study, Co/Pd multilayered films with a few atomic layers of Co were prepared by alternating deposition in an ultrahigh‐vacuum physical‐vapor‐deposition system. The structural parameters were estimated accurately making use of only the angular positions of x‐ray diffraction peaks. The magnetic properties were found to vary greatly depending on Pd predeposition and Pd‐sublayer thicknesses as well as Co‐sublayer thickness. The Pd‐predeposited films were found to have a remarkably high coercivity of 4723 Oe and a greatly enhanced interfacial magnetic anisotropy of 0.72 mJ/m2, which indicates an excellent potential as a magneto‐optical recording medium.

An Experiment and Analysis for Standardize Measurement on CCFL

A method of measuring the current and voltage is suggested in the circuit of cold cathode fluorescent lamps (CCFLs) which are driven at a high frequency of and a high voltage of several kV. It is difficult to measure the current and voltage in the lamp circuit, because the impedance of the probe at high voltage side causes the leakage current and the variation of luminance. According to the analysis of equivalence circuit with the probe impedance and leakage current, the proper measuring method is to adjust the input DC voltage and to keep the specific luminance when the probe is installed at a high voltage circuit. The lamp current is detected with a current probe or a high frequency current meter at the ground side and the voltage is measured with a high voltage probe at the high voltage side of lamp. The lamp voltage() is measured between the ballast capacitor and the lamp electrode, and the output voltage() of inverter is measured between inverter output and ballast capacitor. As the phases of lamp voltage() and current () are nearly the same values, the real power of lamp is the product of the lamp voltage() by the lamp current(). The measured value of the phase difference between inverter output voltage() and lamp current() is appreciably deviated from the calculated value at

Longitudinal and transverse discharges with mercury-rare and xenon gases

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Electron collision ionized plasma waves in the positive column of a fine discharge tube

The properties of longitudinal and transverse discharges are investigated with the use of external electrode tubular lamps, with respect to the characteristics of current and voltage, luminance and spectral radiation. With the mercury-rare gases, a high luminance of over 10 000 cd m−2 is readily obtained in the longitudinal discharge with a long positive column where the spectral radiations from Hg are dominant. However, the luminance is extremely low, a few hundred cd m−2, in the transverse discharge with a short gap where all kinds of atom species are ionized and the intensity of the spectral lines from Ne and Ar is rather high. With pure Xe and a mixture of Xe, the transverse discharge is superior to the longitudinal discharge in that the breakdown voltage is low and the luminance for a high pressure above 200 Torr is relatively high.

Blackening of Inner Glass Surface in Fluorescent Lamps for LCD Backlight

In fluorescent lamp tubes, a few millimetres in radius, operating at several tens of kilohertz, the initiation of light radiation is characterized by the propagation of an electron plasma wave, accompanied by ionization caused by electron collision. Due to the effects of the ionization collision of electrons on the dispersion behaviour of the plasma waves, the electron plasma waves generated by the pulses of operation voltage, propagate along the positive column plasma without experiencing damping. The propagation velocity of radiated light, which represents the propagation of the electron plasma wave, can be higher than the electron thermal velocity.

P-63: Distinguished Student Poster: Effects of Glass Capacitance on the Performance of External Electrode Fluorescent Lamps

The different degrees of blackening were observed at the inner surface of borosilicate, soda-lime, and aluminosilicate glass tubes having different sodium (Na) contents. The sodium contents () within the borosilicate, soda-lime, and aluminosilicate glass tubes were found to be 4%, 14%, and 0.06%, respectively. The degree of blackening was shown to increase as the sodium content within the glass of the fluorescent lamp containing Ne+Ar+Hg gas mixture. Higher degree of blackening was observed from the inner surface of the glass tube coated with . The blackening was found to be originated from the amalgam of generated by the chemical reaction between the mercury ions within the discharge gas and sodium within the glass tube during operation.

P‐80: Impedance Matching in the Inverter Circuit of a 32‐inch LCD TV with EEFL‐BLUs

The efficiency of EEFLs with the new glass tube of high dielectric constant K∼6.6 and low dielectric loss tan δ, reaches 45 lm/W which is ∼ 20 % higher than 38 lm/W in the conventional glasses of K ∼ 5.5. And this new glass tube EEFL also shows a high reliability against pinholes.

EVOLUTION OF THE MOUND MORPHOLOGY IN (111) ORIENTED POLYCRYSTALLINE PD FILMS AND CO/PD MULTILAYERED FILMS WITH PD UNDERLAYERS

The circuit of the inverter has been analyzed with EEFL-BLU for 32″ LCD-TV. The analytic solutions of a lamp current and a lamp voltage are compared with the experimental data with respect to the impedance matching with the inductance and the reactance of lamp system.