최근 Fringe-Field Switching (FFS) 모드는 모든 고화질 액정디스플레이에 적용되고 있다. FFS 모드의 전기광학 특성은 전극 구조, 위상지연값, 러빙각, 셀갭, 액정의 유전율 이방성 (Δε) 크기 및 부호와 같은 셀 및 액정 변수에 따라 크게 의존한다. 본 연구에서는 FFS 모드에서 유전율 이방성의 부호가 다르지만 크기가 동일한 조건에서 FFS모드의 전기광학 특성을 연구하였다. 연구 결과에 의하면 전압 인가시 Δε 절대값이 같더라도 유전율 이방성이 음인 액정의 경우가 탄성변형이 용이해 유전율 이방성 양인 액정에 비해 구동 전압이 약 10% 정도 낮은 결과를 보여주었다. 이러한 결과는 FFS모드의 본질을 이해하는데 큰 도움을 준다고 확신한다.

The aim of this work was to investigate the effects of electrodeposition conditions on the microstructural characteristics of copper thin films. The microstructure of electroplated Cu films was found to be highly dependent on electrodeposition conditions such as system current and current density, as well as the bath solution itself. The current density significantly changed the preferred orientation of electroplated Cu films in a DC system, while the solution itself had very significant effects on microstructural characteristics in a pulse-reverse pulse current system. In the DC system, polarization at high current above 30 mA, changed the preferred orientation of Cu films from (220) to (111). However, Cu films showed (220) preferred orientation for all ranges of current density in the pulse-reverse pulse current system. The grain size decreased with increasing current density in the DC system while it remained relatively constant in the pulse-reverse pulse current system. The sheet resistance increased with increasing current density in the DC system due to the decreased grain size.

Fe-Cr-Al powder porous metal was manufactured by using new electro-spray process. First, ultra-finefecralloy powders were produced by using the submerged electric wire explosion process. Evenly distributed colloid(0.05~0.5% powders) was dispersed on Polyurethane foam through the electro-spray process. And then degreasing andsintering processes were conduced. In order to examine the effect of cell size (200 µm, 450 µm, 500 µm) in process,pre-samples were sintered for two hours at temperature of 1450˚C, in H₂ atmospheres. A 24-hour thermo gravimetricanalysis test was conducted at 1000˚C in a 79% N₂ + 21% O₂ to investigate the high temperature oxidation behavior ofpowder porous metal. The results of the high temperature oxidation tests showed that oxidation resistance increased withincreasing cell size. In the 200 µm porous metal with a thinner strut and larger specific surface area, the depletion ofthe stabilizing elements such as Al and Cr occurred more quickly during the high-temperature oxidation compared withthe 450, 500 µm porous metals.

Electro-accel pedal is needed to raise fuel efficiency by controlled pedal angle signal regardless driver’s willings to fast start or stop pedaling, and to reduce muscle fatigue by designed Ergonomic structure. For this purpose, in this study, we designed new mechanism of accel pedal in a double linkage with two springs to minimize the force of pedaling on main pedal period for HECV in close the future. We have achieved the simulation to dynamic characteristics and experimented to measure the pedal force with proto sample, and confirmed the potentialities this new mechanism.

Spherical Ti-6Al-4V powders in the size range of 250 and 300 µm were uniformly doped with nano-sized hydroxyapatite (HAp) powders by Spex milling process. A single pulse of 0.75-2.0 kJ/0.7 g of the Ti-6Al-4V powders doped with HAp from 300 mF capacitor was applied to produce fully porous and porous-surfaced Ti-6Al-4V implant compact by electro-discharge-sintering (EDS). The solid core was automatically formed in the center of the compact after discharge and porous layer consisted of particles connected in three dimensions by necks. The solid core increased with an increase in input energy. The compressive yield strength was in a range of 41 to 215 MPa and significantly depended on input energy. X-ray photoelectron spectroscopy and energy dispersive x-ray spectrometer were used to investigate the surface characteristics of the Ti-6Al-4V compact. Ti and O were the main constituents, with smaller amount of Ca and P. It was thus concluded that the porous-surfaced Ti-6Al-4V implant compacts doped with HAp can be efficiently produced by manipulating the milling and electro-discharge-sintering processes.

ZnO thin films were grown on a sapphire substrate by RF magnetron sputtering. The characteristics of the thin films were investigated by ellipsometry, X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL), and Hall effect. The substrate temperature and growth time were kept constant at 200˚C at 30 minutes, respectively. The RF power was varied within the range of 200 to 500 W. ZnO thin films on sapphire substrate were grown with a preferred C-axis orientation along the (0002) plan; X-ray diffraction peak shifted to low angles and PL emission peak was red-shifted with increasing RF power. In addition, the electrical characteristics of the carrier density and mobility decreased and the resistivity increased. In the electrical and optical properties of ZnO thin films under variation of RF power, the crystallinity improved and the roughness increased with increasing RF power due to decreased oxygen vacancies and the presence of excess zinc above the optimal range of RF power. Consequently, the crystallinity of the ZnO thin films grown on sapphire substrate was improved with RF sputtering power; however, excess Zn resulted because of the structural, electrical, and optical properties of the ZnO thin films. Thus, excess RF power will act as a factor that degrades the device characteristics.

The multi-direction firing of the optical fiber has been required to induce wider damage zone during the laser-assisted surgery. The optical fibers tend to have poor machinability because of its hardness and brittleness. In this study, we employed the ECDM to fabricate the tip of the optical fiber in cone-shape. The con-shaped tip made the multidirectional emission of the light at the distal end of the fiber. The result showed that the lower electrolyte concentration enhanced the surface quality. The optimal concentration of electrolyte was 15% to make high quality surface of optical fiber tip in this experimental condition. When the voltage was more lower, surface quality had been become better. The suitable voltage was 30V for the effective process time.

Two types of Pt nanoparticle electrocatalysts were composited on Pt nanowires by a combination of an electrospinning method and an impregnation method with NaBH4 as a reducing agent. The structural properties and electrocatalytic activities for methanol electro-oxidation in direct methanol fuel cells were investigated by means of scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. In particular, SEM, HRTEM, XRD, and XPS results indicate that the metallic Pt nanoparticles with polycrystalline property are uniformly decorated on the electro-spun Pt nanowires. In order to investigate the catalytic activity of the Pt nanoparticles decorated on the electro-spun Pt nanowires, two types of 20 wt% Pt nanoparticles and 40 wt% Pt nanoparticles decorated on the electro-spun Pt nanowires were fabricated. In addition, for comparison, single Pt nanowires were fabricated via an electrospinning method without an impregnation method. As a result, the cyclic voltammetry and chronoamperometry results demonstrate that the electrode containing 40 wt% Pt nanoparticles exhibits the best catalytic activity for methanol electro-oxidation and the highest electrochemical stability among the single Pt nanowires, the 20 wt% Pt nanoparticles decorated with Pt nanowires, and the 40 wt% Pt nanoparticles decorated with Pt nanowires studied for use in direct methanol fuel cells.

The aim of this study was to evaluate the post-thawed characteristics of leopard cat semen. In this experiment, semen was collected from two leopard cats (A and B) at wild animal center in Seoul Grand Park in Korea. After collection, the sperms were washed with D-PBS and diluted by the freezing medium (Irvine science, USA) and stored in liquid nitrogen. The post-thawed concentration was for A and for B. The viability of post-thawed sperm from A and B individual was 24.0% and 19.0%, respectively. Pre-freezing motility of A and B individual semen was 68.54% and 56.65. Leopard cat A had more normal sperm than that of B (69.5% vs. 54.5%). Acrosome integrity analysis detected live (14.5% vs. 9.0%), damage (39.0% vs. 44.0%) and dead (46.0% vs. 47.0%) in leopard cat A and B, respectively. The present results concluded that leopard cat semen can be collected successfully by electro-ejaculation method and cryopreserved successfullyfor future use in different assisted reproductive technologies. The cryopreservation protocol needs to be modified for increasing post-thawed viability of leopard cat spermatozoa.

WCl6-EtAlCl2 촉매계를 이용하여 비교적 큰 분자량을 갖는 폴리(페닐아세틸렌)을 합성하였다. 중합반응이 잘 진행되었으며 중합수율은 81%였다. 합성한 폴리(페닐아세틸렌) 분자구조를 NMR(1H-,13C-), IR, UV-visible, 원소분석 등으로 분석한 결과 페닐 치환기를 갖는 공액구조 고분자가 합성되었음을 확인할 수 있었다. 아울러 332 nm의 빛으로 여기시킬 경우 PL 최대 peak는 424 nm에서 관찰되었는데, 이는 2.93 eV의 광 에너지에 해당한다. 이 고분자의 순환 전압전류 그림은 도핑과 탈도핑사이에서 비가역적인 전기화학적 거동을 보여주었다. 이 고분자의 전기화학적 과정이 매우 안정하였으며, 스캔속도에 따른 산화전류 밀도 실험으로부터 이 고분자의 산화-환언 과정은 확산-제어과정에 따르는 것으로 분석되었다.

Pt nanoparticle catalysts incorporated on RuO2 nanowire support were successfully synthesized and their electrochemical properties, such as methanol electro-oxidation and electrochemically active surface (EAS) area, were demonstrated for direct methanol fuel cells (DMFCs). After fabricating RuO2 nanowire support via an electrospinning method, two different types of incorporated Pt nanoparticle electrocatalysts were prepared using a precipitation method via the reaction with NaBH4 as a reducing agent. One electrocatalyst was 20 wt% Pt/RuO2, and the other was 40 wt% Pt/RuO2. The structural and electrochemical properties of the Pt nanoparticle electrocatalysts incorporated on electrospun RuO2 nanowire support were investigated using a bright field transmission electron microscopy (bright field TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. The bright field TEM, XRD, and XPS results indicate that Pt nanoparticle electrocatalysts with sizes of approximately 2-4 nm were well incorporated on the electrospun RuO2 nanowire support with a diameter of approximately 50 nm. The cyclic voltammetry results showed that the Pt nanoparticle catalysts incorporated on the electrospun RuO2 nanowire support give superior catalytic activity in the methanol electro-oxidation and a higher electrochemically active surface (EAS) area when compared with the electrospun Pt nanowire electrocatalysts without the RuO2 nanowire support. Therefore, the Pt nanoparticle catalysts incorporated on the electrospun RuO2 nanowire support could be a promising electrode for direct methanol fuel cells (DMFCs).

Peripheral nerve injuries are very common in clinics and often result in severe functional deficits. The aim of this study was to evaluate the effect of treadmill running and electro-acupuncture on nerve regeneration and functional recovery of muscle activity following sciatic nerve crush injury in a rat model. A comparative study was conducted over 30 days on 60 adult male Sprague-Dawley rats grouped into sham control (C), electro-acupuncture (EA), treadmill (T), and treadmill plus electro-acupuncture (TEA). The left sciatic nerve was crushed for 30 sec using a hemostatic forceps and functional activity was evaluated with sciatic functional tests, nerve conduct velocity, muscle weight, and histology at 10, 20, and 30 days after injury. Muscle weight was significantly (P<0.05) increased between days 10 and 30 in the TEA group. In histology, the degree of damage was scored as C > TEA > T > EA, although necrosis and fibrosis of muscle was observed only in the TEA group. The EA and TEA groups showed rapid recovery with better myelinated axons on day 10. These results suggest that application of the TEA method with balanced exercise is a useful treatment option for peripheral nerve injury regeneration and muscle activity.

Electro-Discharge Sintering (EDS) employs a high-voltage/high-current-density pulse of electrical energy, discharged from a capacitor bank, to instantaneously consolidate powders. In the present study, a single pulse of 0.57-1.1 kJ/0.45 g-atomized spherical powders in size range of 10~30 and consisting of -(Ti, Zr) and icosahedral phases were applied to examine the structural evolution of icosahedral phase during EDS. Structural investigation reveals that high electrical input energy facilitates complete decomposition of icosahedral phase into C14 laves and -(Ti, Zr) phases. Moreover, critical input energy inducing decomposition of the icosahedral phase during EDS depends on the size of the powder. Porous Ti and W compacts have been fabricated by EDS using rectangular and spherical powders upon various input energy at a constant capacitance of in order to verify influence of powder shape on microstructure of porous compacts. Besides, generated heat () during EDS, which is measured by an oscilloscope, is closely correlated with powder size.

This study aims to reveal how EA affects BAX and NF-kB involved in cell deaths from global ischemia, and to do this, observes the changes of BAX and NF-kB caused by EA application after transient global ischemia. The experimental method is to give rise to global ischemia and apply EA to 27 SD rats with the particulars of being six-week-old, male, around-300 gram-weighing, and adapted to laboratory environment for more than a week, and divide them into three groups, that is, GV20 EA group(n=9), L14 EA group(n=9), no-treatment GI group(n=9), and then observe their changes of BAX and NF-kB at the time lapse of 6 hours, 9 hours and 12 hours after ischemia, using western blotting. The numerical decrease of BAX expression at the time lapse of 9 hours after EA application, though not statistically significant, was observed in GV20 EA group and L14 EA group, and the NF-kB expression appeared statistically significant decrease in GV20 EA group and L14 EA group, but the expression was higher in the group with EA application. Therefore, EA application at the early phase of global ischemia is considered to affect BAX and NF-kB and play a positive role in decreasing apoptosis and cell deaths by inflammation.

Multi-walled carbon nanotube (MWCNT)/poly(vinyl alcohol) (PVA) nanocomposite hydrogels were prepared by freezingthawing method for the electro-responsive transdermal drug delivery. MWCNTs were used as the functional ingredient to improve both mechanical and electrical properties of MWCNT/PVA nanocomposite hydrogels. The morphology of nanocomposites revealed the uniform distribution of MWCNTs and the good interfacial contact. The compression moduli of hydrogel matrices increased greatly from 40 to 1500 kPa by forming MWCNT/PVA nanocomposites. The swelling ratio of MWCNT/PVA nanocomposites decreased as the content of MWCNTs increased under no electric voltage applied. However, the swelling ratio of MWCNT/PVA nanocomposites increased as the content of MWCNTs increased under electric voltage applied and the applied electric voltage increased. The drug was released in the electro-responsive manner through the skin due to the electro-sensitive swelling characteristics of MWCNT/PVA nanocomposite hydrogels.

Mo thin films were used for the back electrode because of the low resistivity in the Mo/CuInGaSe2 contact inchalcopyrite solar cells. 1µm thick Mo thin films were deposited on soda lime glass by varying the Ar pressure with the dc-magnetron sputtering process. The effects of the Ar pressure on the morphology of the Mo back electrode were studied andthe relationships between the morphology and electro-optical properties, namely, the resistivity as well as the reflectance of theMo thin films, were investigated. The resitivity increased from 24µΩ·cm to 11833µΩ·cm; this was caused by the increasedsurface defect and low crystallinity as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The surface morphologies ofthe Mo thin films changed from somewhat coarse fibrous structures to irregular and fine celled strucutures with increased surfacecracks along the cell boundaries, as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The changes of reflectances in thevisible light range with Ar pressures were mainly attributed to the surface morphological changes of the Mo thin films. Thereflectance in the visible light range showed the highest value of 45% at 3×10−3Torr and decreased to 18.5% at 3×10−2Torr.

Heck coupling 반응을 이용해서 poly{2-[2-(2,5-bis-dodecyloxy-4-propenyl-phenyl)-vinyl]- 7-methyl-fluoren-9-one(PFone), poly{2-[2-(2,5-bis-dodecyloxy-4-propenyl-phenyl)-vinyl]-7-methyl-fluoren-9-ylidene}-malonitrile(PF2CN)을 합성하였다. 합성한 중합체의 광학적, 전기화학적 특성을 흡수, 형광분광법 및 cyclic voltammetry(CV)를 통해 확인하였다. PFone과 PF2CN 필름의 흡수 극대치는 410 nm과 410.5 nm에서 나타났다. PFone 및 PF2CN의 최대 발광파장은 각각 633과 635nm로 나타났다. PFone과 PF2CN의 band gap은 각각 2.06eV 과 2.36eV이고 CV를 통해 측정한 LUMO 에너지 준위는 -3.36eV 와 -3.46eV로 나타났다.

PAQ(poly-2-[2-(2,5-Bis-dodecyloxy-4-vinyl-phenyl)-vinyl]-anthraquinone)과 PAN4CN(poly- 2-{2-[2-(2,5-Bis-dodecyloxy-4-vinyl-phenyl)vinyl]-10-dicyanomethylene-10H-anthracen-9-ylidene}-malononitrile)을 Heck coupling reaction을 이용하여 합성하였다. 합성한 중합체의 전기적, 광학적 특성은 UV-visible spectra, photoluminescence (PL) spectra 및 cyclic voltammetry 측정을 통해 확인하였다. 흡수 스펙트라 측정 결과, thin film에서의 흡수극대치는 PAQ 와 PAN4CN은 334nm에서 나타났고, 용액에서는 PAQ 338nm, PAN4CN은 336nm 나타났다. 발광 극대치의 측정결과 PAQ는 thin film에서 420nm와 용액상에서는 416nm, PAN4CN은 thin film에서 395nm와 용액에서는 550nm로 각각 나타났다. PAQ과 PAN4CN의 band gap은 각각 2.16 eV, 2.04 eV이고 CV를 통해 LUMO 준위는 -3.64eV, -3.52eV로 나타났다.

Transparent ITO films were deposited on a polycarbonate substrate with RF magnetron sputtering in a pure argon(Ar) and oxygen (O2) gas atmosphere, and then post deposition electro annealed for 20 minutes in a 4×10-1Pa vacuum. Electronbombardment with an accelerating voltage of 100V increased the substrate temperature to 120oC. XRD analysis of the depositedITO films did not show any diffraction peaks, while electro annealed films indicated the growth of crystallites on the (211), (222),and (400) planes. The sheet resistance of ITO films decreased from 103 to 82Ω/□. The optical transmittance of ITO films inthe visible wavelength region increased from 85 to 87%. Observation of the work function demonstrated that the electro-annealingincreased the work function of ITO films from 4.4 to 4.6eV. The electro annealed films demonstrated a larger figure of meritof 3.0×10-3Ω-1 than that of as deposited films. Therefore, the electro annealed films had better optoelectrical performances thanas deposited ITO films.

HI몰랄리티가 9.5 mol/kg-H2O인 HI의 전해-전기투석을 시판의 양이온교환막(CMB)을 이용하여 요오드의 존재하에 실험을 진행하였다. 수소이온 투과의 선택성을 증가시키기 위해, 막은 전자선 가속기를 이용하여 방사선 처리하였다. 방사선 처리한 막의 막특성(막 저항, 이온교환용량, 함수율)을 측정하였다. 각각의 방사선량에서 처리한 막의 2 mol/dm3의 KCl 용액에서 막저항, 이온교환용량과 함수율은 처리하지 않은 막과 거의 동등의 값을 가졌다. HI몰랄리티가 9.5 mol/kg-H2O인 HI의 전해-전투기투석을 75℃, 9.6 A/dm2에서 진행하였다. 전자선 가속기에 의해 방사선 처리한 양이온교환막은 처리하지 않은 막과 비교하여 고분자의 가교구조와 함께 수소이온투과의 높은 선택성을 가졌다.