• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.30-30
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• 2010

The Angle Ring and Cap which is called pressboard are settled at primary and secondary coil winding of 154 kV transformer that can reduce effectively distance of insulation. As it has not manufactured pressboard of Angle Ring and Cap for high voltage grade, insulation components industry especially high voltage transformer has not participate in a competition with worldwide yet. That's why is difficult to make an specialized shape of insulation components of high voltage grade. At first, it is very important to make an utility of deformation manufacturing for high voltage transformer insulation components by itself. Therefore it has finally completed to make an deformation manufacturing utility using an special analysis tools. In this paper, developed insulation components was investigates in tensile strength is introduced.

• 한국전자파학회논문지
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• 제17권3호
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• pp.267-271
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• 2006

본 논문에서는 공간적 전파전파 특성을 고려한 MIMO 안테나에 적용한 OFDM 전송 채널 모형을 사용하여, 채널의 에르고딕 용량을 계산하고 그 특성에 대해 논의한다. 특히 3GPP TR 25.966 V6.1.0에 정의되어 있는 case I의 LOS off 채널의 에르고딕 용량을 구하고, 클러스터 각 퍼짐과 도착 각도(Angle Of Arrival: AOA)의 차이에 따른 채널 용량 변화를 고찰한다. 연구 결과 클러스터 각 퍼짐의 증가에 따라 채널 용량이 증가하며, 35도 이상에서는 큰 증가가 없는 것을 볼 수 있었다.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.100-105
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• 2020

Recently, as display and semiconductor devices have been miniaturized and highly integrated, there is a demand for optimization of the structural characteristics of the thin film accordingly. The sputtering device has the advantage of stably obtaining a desired thin film depending on the material selected for the target. However, due to the structural characteristics of the sputtering equipment, the structural characteristics of the film may be different depending on the incidence angle of the sputtering target material to the substrate. In this study, the characteristics of the thin film material according to the scattering angle of the target material and the incidence position of the substrate were studied to find the optimization design rule of the sputtering equipment. To this end, a Si thin film of 1 ㎛ or less was deposited on the Si(100) substrate, and then the microstructure, reflectance, surface roughness, and thin film crystallinity of the thin film formed for each substrate location were investigated. As a result of the study, it was found that as the sputter scattering angle increased and the substrate incident angle decreased, the gap energy along with the surface structure of the thin film increased from 1.47 eV to 1.63 eV, gradually changing to a non-conductive tendency.

• Wind and Structures
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• 제7권1호
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• pp.41-54
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• 2004

An analysis refinement of the Messina Strait suspension bridge project has been recently required, concerning mainly the yaw angle effects on the multi-box deck section aerodynamics and the vortex shedding at low reduced velocities $V^*$. In particular the possible interaction of the axial flow with the large cross beams has been investigated. An original test rig has been designed at this purpose allowing for both forced motion and free motion aero elastic tests, varying the average angle of attack ${\alpha}$ and the deck yaw angle ${\beta}$. The hydraulic driven test rig allowed for both dynamic and stationary tests so that both the stationary coefficients and the flutter derivatives have been evaluated for each yaw angle. Specific free motion tests, taking advantage from the aeroelastic features of the section model, allowed also the study of the vortex shedding induced phenomena.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.679-682
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• 2006

By adjusting driving voltage, the image quality and optical characteristics have been improved. Based on the experiment results. Optical properties including viewing angle and color shifts at bias voltage 2.4 V are better than those of bias voltage 1 V.

• 소성∙가공
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• 제14권3호
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• pp.282-290
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• 2005

Nowadays, TFT-LCD is widely used as display unit of many digital devices. And, the backlight unit(BLU) is used as a light source of TFT-LCD module. In the backlight unit, the most important component is a light guide, which guides the input light to the TFT-LCD module uniformly. Recently, many researchers have focused on improving the efficiency of BLU by changing the design and structure of a light guide. In the present paper, a series of simulation was performed to find the optimal luminance distribution of emanated light from the given geometry as the first step. From the results of simulations for the light guide with given V-groove pattern, the emanated light from it is mostly affected by the groove angle. In the case of acute angle, about 74 degrees was found as optimal angle to satisfy the restrictions of angular luminance distribution, FWHM, the maximum luminance, etc. However, as far as the average luminance value was concerned, the case of 120 degrees(abtuse angle) was found to be the best while prism films were added to the BLU. As a next step the light guide samples of 74 and 120 degrees were manufactured by DSF method, which was recently proposed by the authors. Of course, most of design parameters were chosen by the aid of simulation results. Finally, the results of average luminance values were compared between the simulation and DSF molded samples.

• 한국진공학회지
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• 제12권S1호
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• pp.92-94
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• 2003

The sputtering yield change of an amorphous Si layer on Si(100) was measured quantitatively for 0.5 keV $O_2^{+}$ and $Ar^{+}$ ion bombardment with in suit MEIS. In the case of 0.5 keV $O_2^{+}$ ion bombardment, at the initial stage of sputtering before surface oxidation, the sputtering yield of Si was 1.4 (Si atoms/$O_2^{+}$) and then decreased down to 0.06 at the ion dose of $3\times10^{16}O_2\;^{+}\textrm{/cm}^2$. In the case of 0.5 keV $Ar^{+}$ ion bombardment, the sputtering yield of Si for the surface normal incidence was 0.56 at the ion dose of 2.5 ${\times}$ 10$^{15}$ $Ar^{+}\textrm{cm}^2$, and rapidly saturated to 1.2 at dose of $7.5\times10^{15}Ar^+\textrm{cm}^2$. For the incidence angle of 80 from surface normal, the sputtering yield of Si was saturated to about 1.4 at the initial stage of sputtering. The surface transient effects, caused by change in sputtering yield at the initial stage of sputtering can be negligible when 0.5 keV $Ar^{+}$ ion at extremely grazing angle was used for sputter depth profiling.g.

• 열처리공학회지
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• 제23권1호
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• pp.17-22
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• 2010

The enhancement of adhesion for Cr film on polycarbonate (PC) substrate with electron irradiation treatment was considered. The electron treatment changes the contact angle of the PC substrates. As increase the electron energy from 300 eV to 900 eV, the contact angle decreases from $90^{\circ}$ to $60^{\circ}C$. It is supposed that electron treatment changes the chemical property of PC substrate into hydrophilic one. The micro surface roughness was also affected by electron treatment. The PC substrates irradiated with intense electron beam of 900 eV show the rougher surface than those of other PC substrates. Cr thin films deposited on the PC substrate treated with electron irradiation at 900 eV show the higher adhesion than that of the Cr thin film deposited untreated bare PC substrates.

• Geomechanics and Engineering
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• 제34권1호
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• pp.103-113
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• 2023

This study focused on understanding the relationship between the design of a tunnel boring machine disc cutter ring and its rock-breaking efficiency, as well as the applicable conditions of different cutter ring types. The discrete element method was used to establish a numerical model of the rock-breaking process using disc cutters with different ring types to reveal the development of rock damage cracks and variation in cutter penetration load. The calculation results indicate that a sharp-edged (V-shaped) disc cutter penetrates a rock mass to a given depth with the lowest load, resulting in more intermediate cracks and few lateral cracks, which leads to difficulty in crack combination. Furthermore, the poor wear resistance of a conventional V-shaped cutter can lead to an exponential increase in the penetration load after cutter ring wear. In contrast, constant-cross-section (CCS) disc cutters have the highest quantity of crack extensions after penetrating rock, but also require the highest penetration loads. An arch-edged (U-shaped) disc cutter is more moderate than the aforementioned types with sufficient intermediate and lateral crack propagation after cutting into rock under a suitable penetration load. Additionally, we found that the cutter ring wedge angle and edge width heavily influence cutter rock-breaking efficiency and that a disc cutter with a 16 to 22 mm edge width and 20° to 30° wedge angle exhibits high performance. Compared to V-shaped and U-shaped cutters, the CCS cutter is more suitable for soft or medium-strength rocks, where the penetration load is relatively small. Additionally, two typical case studies were selected to verify that replacing a CCS cutter with a U-shaped or optimized V-shaped disc cutter can increase cutting efficiency when encountering hard rocks.

• 한국정보전자통신기술학회논문지
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• 제11권3호
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• pp.241-245
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• 2018

본 논문에서 주 블레이드를 V 형태로 설계하고 주 블레이드 각도와 풍속을 변화시켜 최상의 설계조건을 확인하고자 하였다. 주 블레이드 open angle을 $120^{\circ}$유지하고, 각도를 $30^{\circ}$로 변화시킨 sample2와 $60^{\circ}$로 변화시킨 sample3를 비교 하였을 때, sample2는 출력이 3.8[kW], 효율은 0.12로 측정되었고 sample3은 출력이 6.0[kW] 효율은 0.18로 측정되었다. 즉 sample3은 sample2보다 출력이 58%, 효율이 50% 상승되었다. 그리고 주 블레이드 open angle $120^{\circ}$, 각도를 $60^{\circ}$로 고정하여 풍속을 7[m/s]일 때 출력이 6.0[kW]으로 효율은 0.18로 측정되었고, 풍속을 10[m/s]로 변화 주었을 때 출력은 7.7[kW], 효율은 0.23으로 측정되었다. 즉 풍속이 높았을 때 출력은 28%, 효율은 83%가 상승되었다. 또한 sample4는 sample2보다 출력에서 103%, 효율에서 92%가 더 상승하였다.