• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.1126-1133
• /
• 2005

The effects of mean particle size and uniformity coefficient of dredged soils to the liquefaction resistance strength and dynamic characteristics are experimentally studied in this paper. Representative 4 mean particle sizes and 3 uniformity coefficients were selected and 12 representative particle size distribution curves which have different mean particle sizes and uniformity coefficients, were artificially manufactured using the real dredged river soil. Cyclic triaxial tests and torsional shear tests were carried out to analyze the effect of mean particle size and uniformity coefficient to the liquefaction resistance strength and dynamic characteristics of soils.

• Journal of the Optical Society of Korea
• /
• v.20 no.5
• /
• pp.586-592
• /
• 2016

This paper proposes a luminance compensation method using optical sensors to achieve high luminance uniformity of active matrix organic light-emitting diode (AMOLED) displays. The proposed method compensates for the non-uniformity of luminance by capturing the luminance of entire pixels and extracting the characteristic parameters. Data modulation using the extracted characteristic parameters is performed to improve luminance uniformity. In addition, memory size is optimized by selecting an optimal bit depth of the extracted characteristic parameters according to the trade-off between the required memory size and luminance uniformity. To verify the proposed compensation method with the optimized memory size, a 40-inch 1920×1080 AMOLED display with a target maximum luminance of 350 cd/m² is used. The proposed compensation method considering a 4σ range of luminance reduces luminance error from ± 38.64%, ± 36.32%, and ± 43.12% to ± 2.68%, ± 2.64%, and ± 2.76% for red, green, and blue colors, respectively. The optimal bit depth of each characteristic parameter is 6-bit and the total required memory size to achieve high luminance uniformity is 74.6 Mbits.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.7
• /
• pp.13-20
• /
• 2005

For experimental study on the effect of particle size distribution on the liquefaction resistance strength, particle size distribution curves of the dredged soil were investigated. In this process, four mean particle sizes and three uniformity coefficients were defined representatively and twelve representative particle size distribution curves which have different mean particle size and uniformity coefficient, were defined and manufactured by using the real dredged river soil. Cyclic triaxial tests and resonant column tests were carried out to analyze the effect of mean particle size and uniformity coefficient on the liquefaction resistance strength and dynamic characteristics.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2015.05a
• /
• pp.113-113
• /
• 2015

본 연구에서는 thermal evaporation법을 이용하여 제작한 CdTe 후막의 미세구조, 전기적 특성 및 X-선 조사에 따른 특성을 비교분석하였다. 기판온도를 $370{\sim}450^{\circ}C$로 변화시키며 증착하였으며, CdCl2 첨가에 따른 미세구조 변화를 관찰하였다. CdTe 막의 상 하부에 전극을 형성하여 I-V 특성을 평가하고, 실제 X-ray를 샘플에 조사하여 sensitivity를 측정하였다. 박막형성 초기에는 기판온도가 증가함에 따라 grain size가 증가하였지만, grain uniformity는 감소하였다. X-ray 특성향상을 위해서는 grain size와 uniformity 모두 중요한 인자이기 때문에 uniformity 향상을 위해 Cl을 첨가하였다. 미량의 Cl 첨가에서는 큰 변화를 보이지 않았지만 더 많은 양의 Cl 첨가 시, grain size 와 uniformity 모두 증가되는 것을 확인하였으며, 그에 따라 I-V, X-ray 조사 특성 모두 개선되는 것을 확인할 수 있었다.

• Korean Journal of Materials Research
• /
• v.14 no.3
• /
• pp.196-202
• /
• 2004

A numerical simulation based on the finite element method is used to investigate the effect of a reciprocal paddle on the uniformity of deposition rates at a patterned electrode. The calculated deposition rates agreed well with the measured values. The influences of the paddle velocity, the gap between cathodes and paddles, anode size and the distance between the anode and cathode have been studied. The optimum conditions on the paddle and geometric factors for electrodeposit uniformity could be obtained.

• Macromolecular Research
• /
• v.12 no.2
• /
• pp.240-245
• /
• 2004

Monodisperse PMMA micro spheres are prepared by means of a simple soap-free emulsion polymerization in methanol-enriched aqueous medium in a single step process. The size and uniformity of the microspheres are dependent on the polymerization temperature. In a stable system, the uniformity is improved with the polymerization time. The most uniform and stable micro spheres are obtained under mild agitation speed of 100 rpm at 70$^{\circ}C$. The monodisperse PMMA microspheres in the size range of 1.4-2.0 $\mu\textrm{m}$ having less than 5% size variation are successfully achieved with varying concentrations of monomer and initiator. As the monomer and initiator concentrations increase, the larger micro spheres with enhanced uniformity are obtained. However, the decreased amount of water induces the polydisperse PMMA particles due to the generation of secondary particles.

• Journal of Environmental Science International
• /
• v.22 no.11
• /
• pp.1481-1498
• /
• 2013

The SCR (selective catalytic reduction) system is highly-effective technique for NOx reduction from exhaust gases. In this study, the effects of the direction and size of nozzle and the ammonia injection concentration on the performance of SCR system are analyzed by using the computational fluid dynamics method. When the nozzle is arranged in zigzaged direction which is normal to exhausted gas flow, it is shown that the uniformity of gas flow and the NH3/NO molar ratio is improved remarkably. With the change of the ammonia injection concentration from 0.2 vol%(wet) to 1.0 vol%(wet), the uniformity of gas flow shows a good results. As the size of nozzle diameter changes from 6 mm to 12 mm, the uniformity of gas flow is maintained well. It is shown that the uniformity of the $NH_3/NO$ molar ratio becomes better with decreasing the ammonia injection concentration and the size of nozzle diameter.

• Journal of the Semiconductor & Display Technology
• /
• v.21 no.3
• /
• pp.125-129
• /
• 2022

The current display technology tends to be highly integrated with high resolution, the element size is gradually downsized, and the structure becomes complicated. Inductively coupled plasma (ICP) dry etcher of various types of etching equipment is a structure that places a large multi-divisional antenna source on the top lid, passes current to the Antenna, and generates plasma using the induced magnetic field generated at this time. However, in the case of a device of a large area size, a support that can withstand a load structurally is necessary, and when these support portions are applied, arrangement of antenna becomes difficult, which causes reduction in uniformity. As described above, the development of antenna source of a large area having a uniform plasma density on the whole surface is difficult to restrict hardware (H/W). As a solution to this problem, we confirmed the change in uniformity of plasma by applying two kinds of specific shape faraday shield(FICP) to the lower part of the large area upper lid antenna of 6 and 8th more than that generation size. In this thesis, we verify the faraday shield effect which can improve plasma uniformity control of ICP dry etcher equipment applied to medium and large displays.

• Journal of Hydrogen and New Energy
• /
• v.32 no.5
• /
• pp.331-339
• /
• 2021

This study presents a novel way to enhance uniformity of the gas flow inside the solid oxide fuel cell (SOFC), which is critically important to fuel cell performance, by using dimples. A pattern of dimple, which works as a flow distributor/collector, is designed at the inlet and outlet section of a straight channel gas separator. Size of the dimples and the gap between them were changed to optimize the flow uniformity, and any change in size or gap is considered as one design. The results show that some dimple patterns significantly enhance the uniformity compared to baseline, about 4%, while the others slightly reduce it, about 1%. Besides, the dimple pattern also affects to the pressure drop in the flow channel, however the pressure drop in all cases are negligible (less than 26.4 Pa).

• Journal of IKEEE
• /
• v.27 no.4
• /
• pp.679-682
• /
• 2023

In wireless sensor networks, communication failure between sensor nodes causes continuous connection attempts, which results in a large power loss. In this paper, an appropriate distance between the CH(Cluster Head) node and the communicating sensor nodes is limited so that a group of clusters of appropriate size is formed on a two-dimensional plane. To equalize the cluster size, sensor nodes in the shortest distance communicate with each other to form member nodes, and clusters are formed by gathering nearby nodes. Based on the proposed cluster uniformity algorithm, the improvement rate of cluster uniformity is shown by simulation results. The proposed method can improve the cluster uniformity of the network by about 30%.