• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.33-33
• /
• 2007

In PDP industry, the dielectrics and barrier ribs have been required with low dielectric constant, low melting point and Pb-free composition due to the low power consumption, low signal delay time and the environment restriction. We were studied with $B_2O_3-Al_2O_3$-SrO glass systems about optical, thermal and dielectric properties. The glass forming region of the $B_2O_3-Al_2O_3$-SrO glass systems was narrow due to the amount of the glass former $(B_2O_3)$. The glass transition temperature (Tg) of the glasses was at $550{\sim}590^{\circ}C$. The glasses have 6~8 for the dielectric constant. Furthermore, the transmittance of the glasses was over 80% on the range of the visible ray. From the results, the glasses of the $B_2O_3-Al_2O_3$-SrO glass systems should enable to be a good candidate of the PDP devices for information display with low dielectric constant. The aim of this study is to give a fundamental result of new glass system for low dielectric constant in the information display.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.335-335
• /
• 2007

본 연구에서는 RF Magnetron Sputtering 법으로 94:6 wt%의 비율로 Sb가 첨가된 $SnO_2$ 타겟을 사용하여 실온에서 ATO(Antimony doped Tin Oxide) 박막을 증착하고, 열처리가 ATO 박막의 구조적, 전기적, 광학적 특성에 미치는 효과를 연구하고자 하였다. ATO 박막의 두께는 약 200 nm로 증착하였으며, 실험 조건으로는 Ar 유량을 100 seem, 진공도는 1, 5, 10 mTorr로 변화시켰으며 스퍼터링 파워는 100, 150, 200, 250 W로 조절하였다. 증착되어진 박막은 vacuum 상태에서 300, $600^{\circ}C$의 온도에서 열처리를 수행하였으며 결과적으로 스퍼터링 파워가 증가함에 따라 비저항이 감소하였고, 250 W의 파워와 10 mTorr의 공정압력 조건에서 $600^{\circ}C$로 열처리한 ATO 박막은 $5{\times}10^{-3}{\Omega}-cm$의 저항률과 85.3%의 높은 투과도를 가지는 우수한 투명 전도막을 얻을 수 있었다.

• Nuclear Engineering and Technology
• /
• v.42 no.1
• /
• pp.79-88
• /
• 2010

Spent $UO_2$ nuclear fuel discharged from a nuclear power plant (NPP) contains fission products, U, Pu, and other actinides. Due to neutron capture by $^{238}U$ in the rim region and a temperature gradient between the center and the rim of a fuel pellet, a considerable increase in the concentration of fission products, Pu, and other actinides are expected in the pellet periphery of high burnup fuel. The characterization of the radial profiles of the various isotopic concentrations is our main concern. For an analysis, spent nuclear fuels originating from the Yeonggwang-2 pressurized water reactor (PWR) were chosen as the test specimens. In this work, the distributions of some actinide isotopes were measured from center to rim of the spent fuel specimens by a radiation shielded laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system. Sampling was performed along the diameter of the specimen by reducing the sampling intervals from 500 ${\mu}m$ in the center to 100 ${\mu}m$ in the pellet periphery region. It was observed that the isotopic concentration ratios for minor actinides in the center of the specimen remain almost constant and increase near the pellet periphery due to the rim effect apart from the $^{236}U$ to $^{235}U$ ratio, which remains approximately constant. In addition, the distributions of local burnup were derived from the measured isotope ratios by applying the relationship between burnup and isotopic ratio for plutonium and minor actinides calculated by the ORIGEN2 code.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.356-356
• /
• 2010

Tribological behaviors of the hard film on soft substrate system were explored using the hard thin film of diamond-like carbon (DLC) coated the soft polymer of polydimethysiloxane (PDMS). A DLC film with the Young's modulus of 100 GPa was coated on PDMS substrate with Young's modulus of 10 MPa using plasma enhanced chemical vapor deposition (PECVD) technique. The deposition time was varied from 10 sec to 10 min, resulting in nanoscale roughness of wrinkle patterns with the thickness of 20 nm to 510 nm, respectively, at a bias voltage of $400\;V_b$, working pressure 10 mTorr. Nanoscale wrinkle patterns with 20-100 nm in width and 10-30 nm height were formed on DLC coating due to the residual stress in compression and difference in Young's modulus. Nanoscale roughness effect on tribological behaviors was observed by performing a tribo-experiment using the ball-on-disk type tribometer with a steel ball of 6 mm in diameter at the sliding speed of 220 rpm, normal load of 1N and 25% humidity at ambient temperature of $25^{\circ}C$. Friction force were measured with respect to thickness change of coated DLC thin film on PDMS. It was found that with increases the thickness of DLC coating on PDMS, the coefficient of friction decreased by comparison to that of the uncoated PDMS. The wear tracks before and after tribo-test were analyzed using SEM and AFM.

• Biomolecules & Therapeutics
• /
• v.2 no.4
• /
• pp.336-342
• /
• 1994

The general pharmacological properties of EPO were investigated in various animals administering intravenously and in vitro system. The results were as follows. 1. Central nervous system: EPO at doses of 70, 700, 7000 U/kg showed no effect In mice on general behavior, on strychnine- and pentetrazol-induced convulsion and on acetic acid-induced writhing syndrome. The hexobarbital-induced sleeping time in mice was slightly reduced by EPO at a dose of 7000 U/kg but did not change at doses of 70, 700 U/kg. The body temperature in rats was slightly decreased by EPO at doses of 700, 7,000 U/kg but the change was in normal physiological range. 2. Respiratory and cardiovascular system: EPO showed no effect on respiratory rate, blood pressure, heart rate, femoral blood flow, and electrocardiogram in anesthetized dogs at doses of 70, 700, 7000 U/kg. 3. Smooth muscle: EPO at concentrations of 70, 700 U/ml had no effect on the contractile response of isolated guinea pig ileum to histamine and acetylcholine. 4. Water and electrolytes excretion: EPO at dose above 700 U/kg increased urine volume in rats but did not affect the concentrations of $Na^{+},\;K^{+},\;Cl^{-}$ in urine. 5. Gastrointestinal system: EPO(70, 700, 7000 U/kg) had no effect on the intestinal charcoal meal propulsion 6. Blood coagulation system: The administration of EPO(70, 700, 7000 U/kg) had no effect on the plasma prothrombin time(PT) and activated partial thromboplastin time(APTT) in mice. Platelet aggregation induced by ADP and collagen was not influenced by EPO(70 U/ml, 700 U/ml). The overall results obtained indicated that EPO exerts almost no serious pharmacological effect even at a 100-fold clinical dose(7000 U/kg).

• Resources Recycling
• /
• v.20 no.2
• /
• pp.45-53
• /
• 2011

We devised a procedure for the recovery of silicon and tempered glass from waste photovoltaic (PV) modules using optimized conditions. The tempered glass was recovered without any damage using organic solvents. The surface material is removed by applying an acid solution on the surface of the PV cell. Through our proposed method, we offer a much more efficient approach for recycling solar cells with a surfactant than the conventional method. This process, we obtained pure silicon with a yield of 90% by chemical treatment with the surfactant at room temperature for 18 min. The silicon yield was characterized using an inductively coupled plasma-atomic emission spectrometer.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.145-145
• /
• 2010

In this paper, we report that the effects of hydrogen doping on the electrical and optical properties of typical transparent conducting oxide films such as ZnO and $SnO_2$ prepared by magnetron sputtering. Recently, density functional theory (DFT) calculations have shown strong evidence that hydrogen acts as a source of n-type conductivity in ZnO. In this work, the beneficial effect of hydrogen incorporation on Ga-doped ZnO thin films was demonstrated. It was found that hydrogen doping results a noticeable improvement of the conductivity mainly due to the increases in carrier concentration. Extent of the improvement was found to be quite dependent on the deposition temperature. A low resistivity of $4.0{\times}10^{-4}\;{\Omega}{\cdot}cm$ was obtained for the film grown at $160^{\circ}C$ with $H_2$ 10% in sputtering gas. However, the beneficial effect of hydrogen doping was not observed for the films deposited at $270^{\circ}C$. Variations of the electrical transport properties upon vacuum annealing showed that the difference is attributed to the thermal stability of interstitial hydrogen atoms in the films. Theoretical calculations also suggested that hydrogen forms a shallow-donor state in $SnO_2$, even though no experimental determination has yet been performed. We prepared undoped $SnO_2$ thin films by RF magnetron sputtering under various hydrogen contents in sputtering ambient and then exposed them to H-plasma. Our results clearly showed that the hydrogen incorporation in $SnO_2$ leads to the increase in carrier concentration. Our experimental observation supports the fact that hydrogen acting as a shallow donor seems to be a general feature of the TCOs.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.9
• /
• pp.1615-1622
• /
• 2008

We have fabricated the poly-silicon thin film transistor(TFT) which has the LDD-region with graded spacer. The devices of n-channel poly-si TFT's hydrogenated by $H_2$ and $H_2$/plasma processes were fabricated for the devices reliability. We have biased the devices under the gate voltage stress conditions of maximum leakage current. The parametric characteristics caused by gate voltage stress conditions in hydrogenated devices are investigated by measuring/analyzing the drain current, leakage current, threshold voltage($V_{th}$), sub-threshold slope(S) and transconductance($G_m$) values. As a analyzed results of characteristics parameters, the degradation characteristics in hydrogenated n-channel polysilicon TFT's are mainly caused by the enhancement of dangling bonds at the poly-Si/$SiO_2$ interface and the poly-Si grain boundary due to dissolution of Si-H bonds. The structure of novel proposed poly-Si TFT's are the simplicities of the fabrication process steps and the decrease of leakage current by reduced lateral electric field near the drain region.

• Journal of the Korean Magnetics Society
• /
• v.8 no.6
• /
• pp.346-349
• /
• 1998

In order to reduce to the defect density in poly-Si/SiO$_2$ thin films, where poly-Si is either undoped or doped by BF$_2$ implantation, the poly-Si/SiO$_2$ samples have been hydrogenated by rf plasmas of low temperature. Before hydrogenation, both $P_b$ centers and E centers were observed in the poly-Si(undoped)/SiO$_2$ and in the poly-Si(doped)/SiO$_2$. After 30 min hydrogenation, the $P_b$ center was reduced by 80 % doped sample and by 76 % in the undoped sample and the E center was not observed. After 90min hydrogenation, however, increases of the $P_b$ centers and regenerations of the E center were observed in the undoped sample as well as in the doped one. Compared with the undoped sample, the increase of $P_b$ center in the doped one was more dominant.

• Particle and aerosol research
• /
• v.15 no.1
• /
• pp.1-13
• /
• 2019

Current desulfurization and denitrification technologies have reached a considerable level in terms of reduction efficiency. However, when compared with the simultaneous reduction technology, the individual reduction technologies have issues such as economic disadvantages due to the difficulty to scale-up apparatus, secondary pollution from wastewater/waste during the treatment process, requirement of large facilities for post-treatment, and increased installation costs. Therefore, it is necessary to enable practical application of simultaneous SOx and NOx treatment technologies to remove two or more contaminants in one process. The present study analyzes a technology capable of maintaining simultaneous treatment of SOx and NOx even at low temperatures due to the electrochemically generated strong oxidation of the wet-pulse complex system. This system also reduces unreacted residual gas and secondary products through the wet scrubbing process. It addresses common problems of the existing fuel gas treatment methods such as SDR, SCR, and activated carbon adsorption (i.e., low treatment efficiency, expensive maintenance cost, large installation area, and energy loss). Experiments were performed with varying variables such as pulse voltage, reaction temperature, chemicals and additives ratios, liquid/gas ratio, structure of the aeration cleaning nozzle, and gas inlet concentration. The performance of individual and complex processes using the wet-pulse discharge reaction were analyzed and compared.