Earticle

As one of the eletronic device industries has been developed by using a recent printing method, the consumption of Ag paste has been on the rise as well. The printing method has simple processes in comparison with other methods. Also it enables to be large-scaled and to lower price ranges. If UV curing system would be applied to the printing method, energy consumption and dangerousness from curing system can be minimized in a short period of time so that its method can be more eco-friendly. This study conducted an experiment in order to make UV curing Ag paste which is feasible to implement micro patterns with different dispersing agents. The purpose of the study is to analysis the suitable printability for micro pattern and to test dispersibility, hardening properties, conductivity and adhesive stength by measuring viscosity, TI(thixotropy index), G', G'', tanδ(G''/G') after making paste. We have experimented with four dispersing agents. After We did an analysis of characteristic of rheology, conductivity and adhesive stength, etc, We confirmed that the paste added FP 3060 has excellent dispersibility, conductivity and adhesive stength. If the paste has excellent dispersibility, we will expect that micro pattern is made by that.

Surface texturing of tribological application is another attractive technology of friction reducing. Also, reduction of friction is therefore considered to be a necessary requirement for improved efficiency of machine. In this paper attempts to investigate the effect of density for micro-scale dimple pattern on bearing steel flat mated with pin-on-disk. We demonstrated the lubrication mechanism for a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. It is found that friction coefficient is depended on the density of surface pattern. It was thus verified that micro-scale dimple could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions from based on friction map. Lubrication condition regime has an influence on the friction coefficient induced the density of micro dimple.

It is well known that Morpho butterflies show distinctive, brilliant and iridescent colors and have micro-nano scale structures, instead of dyes and pigments, on their wings. This structural coloration is regarded as a novel technique to express color with a long lifetime, ease and precise tenability. Here, we studied optical multilayer thin films with thickness of several tens of nm ($TiO_2$ and $SiO_2$) and lens-shape micro-patterns. Fabrication and characterization of the multilayer stacking structure and the micro-pattern structure were performed and the films were analyzed via several optical measuring techniques. Finally, we discussed how the micro-pattern structure could enhance independence with color changes according to the viewing angle.

This study was performed as a part of the research on the development of a maskless and electroless process for fabricating metal micro/nanostructures by using a nanoindenter and an electroless deposition technique. $2-{\mu}m$-deep indentation tests on Ni and Cu samples were performed. The elastic recovery of the Ni and Cu was 9.30% and 9.53% of the maximum penetration depth, respectively. The hardness and the elastic modulus were 1.56 GPa and 120 GPa for Ni and 1.51 GPa and 104 GPa for Cu. The effect of single-point diamond machining conditions such as the Berkovich tip orientation (0, 45, and $90^{\circ}$ ) and the normal load (0.1, 0.3, 0.5, 1, 3, and 5 mN), on both the deformation behavior and the morphology of cutting traces (such as width and depth) was investigated by constant-load scratch tests. The tip orientation had a significant influence on the coefficient of friction, which varied from 0.52-0.66 for Ni and from 0.46- 0.61 for Cu. The crisscross-pattern sample showed that the tip orientation strongly affects the surface quality of the machined are a during scratching. A selective deposition of Cu at the pit-like defect on a p-type Si(111) surface was also investigated. Preferential deposition of the Cu occurred at the surface defect sites of silicon wafers, indicating that those defect sites act as active sites for the deposition reaction. The shape of the Cu-deposited area was almost the same as that of the residual stress field.

The objective of this work is to suggest a mastless pattern fabrication technique using the combination of machining by Nanoindenter(equation omitted) XP and HF wet etching. Sample line patterns were machined on a borosilicate surface by constant load scratch (CLS) of the Nanoindenter(equation omitted) XP with a Berkovich diamond tip, and they were etched in HF solution to investigate chemical characteristics of the machined borosilicate surface. All morphological data of scratch traces were scanned using atomic force microscope (AFM).

Micro features on the surface are well-known to have significant effects on optical or mechanical properties such as the optical interference, reflectance at the surface, contact angle, interfacial friction, etc. These surface micro features are increasingly employed to enhance the functionality of the applications in various application areas such as optical components for LCD or solar panel. Diverse surface features have been proposed and some of them are showing excellent efficiency or functionality, especially in optical applications. Most applications employing the micro features need manufacturing process for mass production and the injection molding and roll-to-roll forming, which are typical processes for mass production adopting polymeric materials, may be also preferred for micro patterned plastic product. Since the functionality or efficiency of the surface structures generally depends on the shape and the size of the structure itself or the array of the structures on the surface, it would be very important to replicate the features very precisely as being designed during the molding the micro pattern applications. In this paper, a series of research activities is introduced for roll-to-roll forming of micro patterned film including filling of patterns with UV curable resin, demolding of surface structures from the roll tool, control of surface energy and cure shrinkage of resin and dispose time and intensity of the UV light for curing of UV curable resin.

Recently in the display industry, demands for high-luminance and resolution of display devices have been steadily increasing. Generally, micro linear patterns are applied to an optical film in order to improve its properties of light. However, these patterns are easily viewed to eyes and moire phenomenon can be occurred. Micro random patterns are proposed as a method to solve these problems, increasing light-luminance and light-diffusion. However, conventional pattern manufacturing technologies have long processing times and high costs making it difficult to apply to large area molds. In order to combat this issue, micro-random patterns are formed by using a roll to plate indentation method along with abrasive paper tools composed of AlSiO2, SiC, and diamond grains. Also, forming properties, such as size and fill-factor of random patterns, are analyzed depending on type, mesh of abrasive paper tools, and indentation forces.

EHD (electro-hydro-dynamics) patterning was performed under atmospheric pressure at room temperature in a single step. The drop diameter smaller than nozzle diameter and applied high viscosity conductive ink in EHD patterning method provide a clear advantage over the piezo and thermal inkjet printing techniques. The micro electrode pattern was printed by continuous EHD patterning method using 3-type control parameters (input voltage, patterning speed, nozzle pressure). High viscosity (1000cps) conductive ink with 75wt% of silver nanoparticles was used. EHD cone type nozzle having an internal diameter of $50{\mu}m$ was used for experimentation. EHD jetting mode by input voltage and applied 1st order linear regression in stable jet mode was analyzed. The stable jet was achieved at the amplitude of 1.4~1.8 kV. $10{\mu}m$ micro electrode pattern was created at optimized parameters (input voltage 1.6kV, patterning speed 25mm/sec and nozzle pressure -2.3kPa).

Surface roughness of mechanical components is an important factor which affects the tribological phenomena. Various surface patterns have been applied to surfaces to improve the tribological characteristics of mechanical components. In this work, the friction reduction effect of micropatterns on silicon was investigated. For this purpose, micro-dimple patterns were fabricated on silicon wafer by DRIE process. In the friction experiments silicone oil was used as lubricant. Also, the lubricant was cleaned to simulate a lubricant depleted condition. In depleted lubricated condition, friction coefficient of micro-pattern specimens was lower than specimens without micro-patterns. It was found that friction reduction effect of micro-pattern could be successfully maintained even after cleaning the lubricant on the surface.

Micro/nano patterns for optical concentration and diffusion have been studied in the various fields such as displays, optics, and sensors. Conventional micro patterns were continuous and linear shapes due to using linear-type light sources, however, recently non-continuous patterns have been applied as point sources are used for dot-type light sources such as LEDs and OLEDs. In this study, a hybrid machining technology combining an indentation machining method and an AAO process was developed for manufacturing the non-continuous micro patterns having nano patterns. First, mirror-like surfaces ($R_a<20nm$) of pure Aluminum substrates were obtained by optimizing cutting conditions. Then, The letter of 'K' consisting of the arrays of the micro patterns was manufactured by the indentation machining method which has a similar principle to indentation hardness testing. Finally, nano patterns were machined by AAO process on the micro patterns. Conclusively, a specific letter having nano-micro hybrid patterns was manufactured in this study.

Some surface pattern of tribological application is an attractive technology of engineered surface. Therefore, friction reduction is considered to be necessary for improved efficiency of machine. This study investigated the effect of friction property for angles of micro-crosshatch groove surface pattern on bearing steel using pin-on-disk test. We obtain sample which can be fabricated by photolithography process. We discuss the friction property depend on an angle of crosshatch groove surface pattern. We can verify the lubrication mechanism as Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter under the lubrication condition. It was found that the friction coefficient was related to angle of crosshatch groove pattern on contact surface.

The ball-end milling process is widely used in the die/mold industries, and it is very suitable for the machining of free-from surfaces. However, cusps(or scallops) remaining at the machined part along the cutter paths require anothe finish process such as polishing or grinding. In this study, a high sped micro ball-end milling method has been suggested for the finish of free- form surfaces. A new tool path which makes the geometrical roughness of workpiece be constant through the machined surface has been developed. In the high speed machining of micro ball-end muling experimets, the developed tool paths have been successfully applied. And it was concluded that the surface roughness from this finish cuts of micro ball-end milling process was acceptable.

본 연구에서는 미세패턴 성형이 가능하도록 개발된 초음파 미세패턴 제조시스템을 이용하여 RFID TAG 안테나 형상의 미세패턴 성형기술을 개발하였다. 미세패턴 제조시스템에 종진동 모드의 초음파 공구 혼을 설치하여 절연시트 표면에 RFID TAG 안테나 형상의 미세패턴 안테나 형상을 초음파 압입 성형공정 기술을 개발하였다. 초음파 성형기술 은 60㎑ 공구 혼을 공진설계 기법을 적용하여 제작하였고, 미세패턴 제조시스템을 이용하여 200㎛ 이하의 절연 시트지 에 두께가 25㎛의 코일 와이어를 초음파 압입 성형을 할 수 있다. 초음파 압입 성형 시 코일 와이어의 단선, 박리 및 꼬임 현상 없이 최소선폭 150㎛인 안테나 형상을 성형할 수 있었다.

In this study, we developed a micropattern technology in the shape of RFID TAG antenna using ultrasonic micropattern manufacturing system developed to enable micropattern technology. The ultrasonic tool horn in longitudinal vibration mode was installed in the micropattern manufacturing system to develop the ultrasonic press technology for the micropattern antenna shape of the RFID TAG antenna shape on the insulating sheet surface. The ultrasonic shaping technology was manufactured by applying the resonance design technique to a 60㎑ tool horn, and by using the micropattern manufacturing system, the coil wire having a thickness of 25μm can be ultrasonically press-molded on an insulating sheet of 200μm or less. In ultrasonic press technology, the antenna shape having a minimum line width of 150μm could be molded without disconnection, peeling, or twisting of the coil wire.

본 논문에서는 얼굴 표정 인식을 위한 지역미세패턴(local micro pattern)의 하나인 LBP(Local Binary Pattern) 코드의 잡음에 대한 단점을 해결하기위하여 새로운 미세패턴 방법인 LDP(Local Directional Pattern)를 제안한다. 제안된방법은 LBP의 문제점을 해결하기 위해 m × m 마스크를 이용하여 8개의 방향 성분을 구하고, 이를 크기에 따라서 정렬한 후 상위 k개를 선정하여 해당 방향을 나타내는 비트를 1로 설정한다. 그리고 8개의 방향 비트를 순차적으로 연결하여 최종 패턴 코드를 생성한다. 실험결과, 제안된 방법은 기존 방법에 비해 회전에 대한 영향이 적으며, 잡음에 대한적응력이 현저히 높았다. 또한, 제안된 방법을 기반으로 얼굴의 영구적인 특징과 일시적인 특징을 함께 표현하는 새로운 지역미세패턴의 개발이 가능함을 확인하였다.

This study proposed LDP (Local Directional Pattern) as a new local micro pattern for facial expressionrecognition to solve noise sensitive problem of LBP (Local Binary Pattern). The proposed method extracts8-directional components using m × m mask to solve LBP's problem and choose biggest k components, eachchosen component marked with 1 as a bit, otherwise 0. Finally, generates a pattern code with bit sequence as8-directional components. The result shows better performance of rotation and noise adaptation. Also, a new localfacial feature can be developed to present both PFF (permanent Facial Feature) and TFF (Transient Facial Feature)based on the proposed method.

최근 토지피복도는 경관 모자이크의 공간적 구성, 기능 및 변화와 같은 공간 패턴을 분석하기 위해 그 활용도가 지속적으로 증가하고 있다. 본 논문에서는 토지피복도를 활용한 경관 모자이크 패턴 분석 시스템을 제안하기 위해서 영역기반 영상처리 기법으로 경관 모자이크의 요소인 패치를 추출하고, 추출된 패치의 경관분석 측정요소를 패치 레벨과 클래스 레벨에서 계산하였다. 계산된 측정요소로 공간관계를 표현할 수 있는 패치기반의 공간 패턴을 제안한다. 제안된 시스템은 시스템의 유효성을 확인하기 위하여 광주광역시의 범례별 토지이용 현황 및 패치의 공간패턴을 확인한다.

Recently, the use of land cover maps has been continuously increasing to analyze spatial patterns such as spatial compositions, functions and changes of landscape mosaics. In this paper, we propose a landscape analysis system that extracts patches, which is an element of landscape mosaics, in the land cover map using region-based image processing technique, and computes patch-based measures at patch level and class level. Also we propose a patch-based spatial pattern that can represent spatial relations using the computed measures. To validate the proposed system's effectiveness, we apply to Gwangju metropolitan city and analyze Gwangju's land use and spatial patterns.

본 연구에서는 둔촌동 습지에서 미지형이 식물 군락 구성에 미치는 영향을 연구하기 위하여 2007~2008년에 걸쳐 지형에따른 수위 변화와 식물 군락의 변화를 조사하였다. 조사 지역을 지대가 낮은 지형부터 높은 지형까지 4개 구역으로구분하여 조사하였으며, 각각의 구역은 조사 지역 면적 대비 약 11%, 10%, 18%, 24%의 면적을 가지고 있었다. 조사 기간동안 수환경의 pH는 6.10(±0.13), 전기전도도는 51.5(±6.0)㎲/cm이었으며, PO4-P, NO3-N, NH4-N은 각각 0.04(±0.02)mg/L,0.14(±0.07)mg/L 그리고 0.01mg/L 이하로 유지되었다. 2008년 3~4월 누적 강수량이 2007년 대비 약 56%로 적었던 것이지대가 낮은 지형에서 수위 환경 차이를 유발하여 식물 군락 형성에 매우 큰 영향을 미쳤으며, 지형의 높이에 따라 해당구역을 우점하는 식물 길드가 다르게 나타났다. 이러한 결과는 종자로부터 생활사가 시작되는 1년생 식물 종들이 조사지역을 전체적으로 우점하였기 때문이며, 다양한 길드의 식물들이 혼재하기 위해서는 높이 구배가 있는 미지형이조성되어야 한다는 것을 의미한다.

The purpose of this study is to investigate the effect of micro-topography to vegetation pattern in Dunchon-dong wetland. Tocharacterize the effect of micro-topography, changes in water level and vegetation pattern were monitored from 2007 to 2008. Depending on the relative elevation, the study site was divided into 4 sectors. The relative areas of sectors in ascending orderwere 11%, 10%, 18% and 24%, respectively. During investigation period, average water pH was 6.10 (±0.13), electronconductivity was 51.5 (±6.0)㎲/cm, PO4-P, NO3-N and NH4-N concentration were 0.04 (±0.02)mg/L, 0.14 (±0.07)mg/L, andlower than 0.01mg/L, respectively. Water level was very changeable in low-water season because the area of lowest sector wassmall. This characteristic increased the effect of difference of accumulated precipitation from March to April in 2007 and 2008to plant community composition in lower sectors. Different plant guilds dominated respective sectors and annual plants weremajor dominant species in the study site. This study suggested that the elevation gradients are necessary to create the habitatsfor various plant guilds in wetland.