In order to apply to high-nickel cathodes for high-capacity and stability enhancement of lithium-ion batteries, the characteristics of the coating film were reviewed using the conventional nickel plating method. The surface morphology of the plating layer and the measurement of the surface roughness were analyzed according to scan size and rate using the contact mode of Atomic Force Microscopy. The hydrogen ion concentration (pH) of the electrolyte played an important role in shaping the metal ion plating. As the overpotential of the surface increased during plating, the crystals grew in a direction other than the main crystal growth direction. The increase in on-time during pulse plating appears to result in coarse particles as much of the applied current is consumed by the reduction of hydrogen ions, resulting in lower current efficiency. From the AFM image, it was confirmed that the blackening of the plated film was due to a partial overvoltage phenomenon during electrolytic degreasing. In order to be used as a high-nickel cathode, it seems that the current must be uniformly distributed on the surface of the substrate during plating.

Tungsten oxide(WO3) films with uniform surface morphology are fabricated using a spin-coating method for applications of electrochromic(EC) devices. To improve the EC performances of the WO3 films, we control the heating rate of the annealing process to 10, 5, and 1 oC/min. Compared to the other samples, the WO3 films fabricated at a heating rate of 5 oC/min shows superior EC performances for transmittance modulation(49.5 %), response speeds(8.3 s in a colored state and 11.2 s in a bleached state), and coloration efficiency(37.3 cm2/C). This performance improvement is mainly related to formation of a uniform surface morphology with increased particle size without any cracks by an optimized annealing heating rate, which improves the electrical conductivity and electrochemical activity of the WO3 films. Thus, the WO3 films with a uniform surface morphology prepared by the optimized annealing heating rate can be used as a potential candidate for performance improvement of the EC devices.

계면중합법은 혼합되지 않은 두 용액에 용해되어 있는 반응성 단량체들이 계면에서 중합되는 기술로 다양한 분야 에 응용되고 있다. 이 중, 수처리 분리막의 경우 m-phenylene diamine과 Trimesoyl chloride를 반응물로 사용하고 있다. 분리 막의 성능은 다양한 중합 성능에 의해 영향을 받고 있으며, 본 연구에서는 유기 용액의 퍼짐 속도가 어떻게 분리막 표면 및 구조에 영향을 주는지를 주사전자현미경을 통해 고찰하였다. 퍼짐 속도는 7.6과 25 mm/sec로 조절하였으며, 유기상 용액은 1~3방울까지 조절하였다. 관찰된 결과는 퍼짐 속도가 7.6 mm/sec에서는 한 방울 떨어트릴 경우, 25 mm/sec에서는 두 방울 떨어트릴 경우 폴리아마이드 막에 균열을 발견할 수 없었다. 반면 나머지 경우에 모두 균열이 발생하였다. 따라서, 초기 유기 용액의 퍼짐 속도는 폴리아마이드 분리막의 성능에 영향을 줄 것으로 관찰되었다.

In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(−170 mV) of the Cu electrode as a substrate was shown, the electrode potential(Edep) at the Ton of electrodeposition and the deposition potential(−600 mV) of the surface of the electrodeposited Co film after Toff and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of Edep and Eimm. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(−280 mV) of the Cu electrode as the substrate exhibited the deposition potential(−615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the Edep of electrodeposition at the Ton of each pulse and the Eimm at the Toff varied greatly each time the pulse current was applied. From 20 % to less than 90% of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.

Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with 15~20 μm dia. of Al2O3 media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.

저온스트레스에 따른 차나무 잎의 변화와 카테킨, 카페인, 아미노산대사 그리고 환원당 등 다양한 대사물의 함량 변화를 구명하였다. 저온스트레스 피해를 입은 실외포장의 차나무 잎은 세포크기, 기공 및 엽맥세포의 크기가 저온스트레스를 입지 않은 온실 재배 녹차잎에 비해 작았다. 저온스트레스 피해를 입은 실외포장의 차나무 잎에서 카페인과 카테킨의 함량은 온실 재배 차나무보다 높았다. 그러나 아미노산의 함량은 저온스트레스 피해를 입은 실외포장의 차나무 잎보다 온실에서 재배한 차나무가 높았다. 환원당 함량은 실외포장의 차나무에서 낮았다. 인위적 저온스트레스 처리 결과 환원당의 함량은 저온스트레스 처리 2시간까지는 증가하였다가 이후는 감소하였다. 이 결과는 저온스트레스가 차나무 잎의 형태적 변화와 더불어 카페인과 카테킨 그리고 당 등 대사물의 영향을 미친다는 것을 나타낸다.

In this study, highly sensitive hydrogen micro gas sensors of the multi-layer and micro-heater type were designed and fabricated using the micro electro mechanical system (MEMS) process and palladium catalytic metal. The dimensions of the fabricated hydrogen gas sensor were about 5mm×4mm and the sensing layer of palladium metal was deposited in the middle of the device. The sensing palladium films were modified to be nano-honeycomb and nano-hemisphere structures using an anodic aluminum oxide (AAO) template and nano-sized polystyrene beads, respectively. The sensitivities (Rs), which are the ratio of the relative resistance were significantly improved and reached levels of 0.783% and 1.045 % with 2,000 ppm H2 at 70˚C for nano-honeycomb and nano-hemisphere structured Pd films, respectively, on the other hand, the sensitivity was 0.638% for the plain Pd thin film. The improvement of sensitivities for the nano-honeycomb and nano-hemisphere structured Pd films with respect to the plain Pd-thin film was thought to be due to the nanoporous surface topographies of AAO and nano-sized polystyrene beads.

울릉분지 남서부의 대륙붕-대륙사면 해저지형과 지질 특성을 규명하고, 이들에 영향을 주는 지질학적 요인을 파악하기 위하여 다중빔 음향측심자료와 표층퇴적물 입도를 분석하였다. 연구지역의 대륙붕은 약 (0.5˚의 경사로 수심 100 m 이내에서 나타나는 내대륙붕과 약 0.2˚의 경사로 수심 100-300 m 이내에서 나타나는 외대륙붕으로 구분할 수 있다. 대륙사면에는 다양한 규모(~121 km2)와 경사(최대 24.3˚)를 갖는 8개의 사면붕괴 지형이 관찰된다. 각 사면붕괴 지형은 서로 인접해 있으며, 해저 지진과 전지구적 해수면 변동의 강한 영향 하에서 연속적으로 발생된 해저사태 기원으로 추정된다. 내대륙붕과 대륙사면은 세립질 퇴적물이 우세하지만, 외대륙붕은 조립질 퇴적물이 우세하다. 표층퇴적물 분포양상은 해수면 변동으로 인한 영향을 주로 받은 것으로 해석된다. 외대륙붕은 저해수면 시기 동안 퇴적된 조립질 잔류 퇴적물로, 내대륙붕은 고해수면 시기동안 퇴적된 현생의 세립 퇴적물로 피복되어 있다. 대륙사면의 표층퇴적물은 저해수면 시기에도 깊은 수심에서 반원양성 대류작용으로 공급된 세립퇴적물로 구성된다.

The electrical properties and surface morphology changes of a silicon wafer as a function of the HF concentration as the wafer is etched were studied. The HF concentrations were 28, 30, 32, 34, and 36 wt%. The surface morphology changes of the silicon wafer were measured by an SEM (80˚ tilted at ×200) and the resistivity was measured by assessing the surface resistance using a four-point probe method. The etching rate increased as the HF concentration increased. The maximum etching rate 27.31 μm/min was achieved at an HF concentration of 36 wt%. A concave wave formed on the wafer after the wet etching process. The size of the wave was largest and the resistivity reached 7.54 ohm·cm at an 30 wt% of HF concentration. At an HF concentration of 30 wt%, therefore, a silicon wafer should have good joining strength with a metal backing as well as good electrical properties.

In the present work, exfoliated graphite nanoplatelets (EGN) of 1 μm in average particle size, which were prepared by heating at 900℃ and then subjected to ultrasonic, ball-milling, and vibratory ball-milling techniques, were uniformly incorporated into phenylethynyl-terminated polyimide (PETI-5) resin. The fracture surface morphology and the electrical resistivity of the EGN/PETI-5 composites were investigated. The results showed that the fracture surfaces and the electrical resistivity strongly depended on the EGN content. The fracture surfaces became more ductile and roughened with increasing EGN and the electrical resistivity was gradually decreased with increased EGN loading, indicating the percolation threshold at 5 wt% EGN.

This study examined the effect of current density on the surface morphology and physical properties of copper plated on a polyimide (PI) film. The morphology, crystal structure, and electric characteristics of the electrodeposited copper foil were examined by scanning electron microscopy, X-ray diffraction, and a four-point probe, respectively. The surface roughness, crystal growth orientation and resistivity was controlled using current density. Large particles were observed on the surface of the copper layer electroplated onto a current density of 25 mA/cm2. However, a uniform surface and lower resistivity were obtained with a current density of 10 mA/cm2. One of the important properties of FCCL is the flexibility of the copper foil. High flexibility of FCCL was obtained at a low current density rather than a high current density. Moreover, a reasonable current density is 20 mA/cm2 considering the productivity and mechanical properties of copper foil.

Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from 25˚C to 500˚C, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at 500˚C, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the Jsc values from 9.94 mA/cm2 for the flat Ag back reflector at 25˚C to 13.36 mA/cm2 for the rough one at 500˚C. A conversion efficiency of 7.60% (Voc = 0.93, Jsc = 13.36 mA/cm2, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.

Reflection properties, such as specular reflection and diffuse reflection, are very important optical properties for the reflector, which has high reflectance in the display and architecture industry. Calcite is lowcost, nontoxic, and stable over a wide temperature range. Therefore, it is one of the most widely using fillers in many industries and has some advantages over titania as a filler to improve reflectance. However, optical properties, especially those of ceramic-filled composites, have not been analyzed. We studied the reflectance of calcite composites with their surface roughness. The reflectance of the composites was determined using a UV-visible spectrometer. The surface morphology and the micro-structure of the composites were investigated by atomic force microscope. The reflectance of the composites was improved by increasing the content of calcite in the calcite-frit composite. The reflectance is related with the surface roughness in the composites. However, the reflectance depends on the calcite contents in materials with similar surface roughness.

Changes in the surface morphology and light scattering of textured Al doped ZnO thin films on glasssubstrates prepared by rf magnetron sputtering were investigated. As-deposited ZnO:Al films show a hightransmittance of above 80% in the visible range and a low electrical resistivity of 4.5×10-4Ω·cm. The surfacemorphology of textured ZnO:Al films are closely dependent on the deposition parameters of heater temperature,working pressure, and etching time in the etching process. The optimized surface morphology with a cratershape is obtained at a heater temperature of 350oC, working pressure of 0.5 mtorr, and etching time of 45seconds. The optical properties of light transmittance, haze, and angular distribution function (ADF) aresignificantly affected by the resulting surface morphologies of textured films. The film surfaces, havinguniformly size-distributed craters, represent good light scattering properties of high haze and ADF values.Compared with commercial Asahi U (SnO2:F) substrates, the suitability of textured ZnO:Al films as frontelectrode material for amorphous silicon thin film solar cells is also estimated with respect to electrical andoptical properties.

The effects of the field emission property in relation to the surface morphology and adhesion force were investigated. The single-wall-nanotube-based cathode was obtained by use of an in-situ arc discharge synthesis method, a screen-printing method and a spray method. The morphologies of the formed emitter layers were very different. The emission stability and uniformity were dramatically improved by employing an in-situ arc discharge synthesis method. In this study, it was confirmed that the current stability and uniformity of the field emission of the cathode depend on the surface morphology and adhesion force of the emitters. The current stability of the field emission device was also studied through an electrical aging process by varying the current and electric field.