• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.561-567
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• 2008

The objectives of this study is to: (1) develop how applications for driving simulator of national highway safety designs when those are appeared; (2) examine the degree to which those geometric designs of the horizontal and vertical profile; and (3) search positive safety and passive highway safety design of the point at which highway alignment factors initiate driving safety to facility or highway design.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.1-4
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• 2000

We have developed a high performance vertical alignment TFT-LCD, that shows a high light transmittance, and wide viewing angle characteristics with an unusually high contrast ratio. In order to optimize the electro-optical properties we have studied the effect of cell parameters, multi-domain structure and retardation film compensation. With the optimized cell parameters and process conditions, we have achieved a 24" wide UXGA TFT-LCD monitor (16:10 aspect ratio 1920X1200) showing a contrast ratio over 500:1, panel transmittance near 4.5%, response time near 27 ms, and viewing angle higher than 80 degree in all directions.

• 천문학회지
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• 제40권4호
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• pp.113-118
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• 2007

Recently far infra-red (FIR) polarization of the $850{\mu}m$ continuum emission from T Tauri disks has been detected. The observed degree of polarization is around 3 %. Since thermal emission from dust grains dominates the spectral energy distribution at the FIR regime, dust grains might be the cause of the polarization. We explore alignment of dust grains by radiative torque in T Tauri disks and provide predictions for polarized emission for disks viewed at different wavelengths and viewing angles. In the presence of magnetic field, these aligned grains produce polarized emission in infrared wavelengths. When we take a Mathis-Rumpl-Nordsieck-type distribution with maximum grain size of $500-1000{\mu}m$, the degree of polarization is around 2-3 % level at wavelengths larger than ${\sim}100{\mu}m$. Our study indicates that multifrequency infrared polarimetric studies of protostellar disks can provide good insights into the details of their magnetic structure.

• 대한교통학회지
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• 제23권3호
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• pp.73-84
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• 2005

도로기하구조 설계기준은 운전자의 안전성 향상과 원활한 주행능력을 제공할 수 있도록 마련되었으나 지형조건이 열악한 우리나라의 경우 부득이 설계기준이 의도하는 방향과 운전자가 인지하는 특성에 차이를 보임으로써 안전성에 문제점이 있는 경우가 많다. 이러한 교통사고의 위험성을 감소시키기 위한 대책 중에 하나로 도로안전시설물을 설치하지만 설치한 안전시설물에 대한 평가는 제대로 이루어지지 않고 있으며, 특히 도로환경적 요인과 인적요인과의 관련성에 대한 연구는 상당히 미흡한 실정이다. 본 연구에서는 도로 이용자들이 종단선형구간에서 느끼는 도로안전성 요인을 파악하기 위하여 차량시뮬레이터(Driving Simulator)와 3D 그래픽 화면으로 종단선형구간을 재현하고 도로안전시설물의 설치 유, 무에 따라 운전자가 느끼는 안전성의 변화와 도로 이미지를 조사하였다. 조사된 데이터를 바탕으로 수량화 제II류에 의한 정준상관분석을 실시하여 도로 안전성의 영향 요인을 분석하였으며 수량화제 I류에 의한 모형화를 실시하여 안전성을 예측한 결과 도로안전시설물과 운전자가 느끼는 안전성과의 관계를 명확히 규명할 수 있었다.

• Medical Lasers
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• 제9권1호
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• pp.44-50
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• 2020

Background and Objectives To evaluate the rotational stability of AcrySof toric intraocular lenses (IOL) by considering lapse of postoperative time and influence of capsulorhexis contraction. Materials and Methods A prospective, masked, single center study was conducted on 19 patients who had undergone microcoaxial cataract surgery and AcrySof toric IOL implantation. Slit-lamp retroillumination photographs of anterior segments were obtained from all patients after 1 week, 1 month and 3 months post-surgery. The degree of alteration of the postoperative IOL axis alignment and the amount of anterior capsular shrinkage were analyzed using Adobe Photoshop software. Results The mean degree of toric IOL axis misalignment was 2.18 (±20.2) degrees at 3 months follow-up. Quadrant analysis of the capsulorhexis aperture area at 1 week and 1 month post-operative, showed counterclockwise IOL rotation when the capsule contraction was dominant in the haptic part as well as clockwise rotation when dominant in the non-haptic part (p = 0.015). Conclusion The direction and degree of AcrySof toric IOL rotation differed throughout the follow-up period. Since most misalignments were found on the first post-operative day, physicians should try to minimize peri-operative risk factors that influence IOL rotation. There was also a correlation between the part of anterior capsule contraction and the direction of IOL rotation.

• 천문학회보
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• 제45권1호
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• pp.33.3-34
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• 2020

The Milky Way (MW) and other systems including M31 and Cen A have flattened structures of their satellites (Disk of Satellites, DoS). Such structures are rare in simulations under the ΛCDM paradigm. DoS is known to depend mainly on 1) the alignment of satellite orbits and 2) the degree of central concentration of satellites. In this work, we examine quantitatively how these two parameters affect the flatness of a system. We find that the MW-like DoS is rare in IllustrisTNG100 simulation because its two parameters are out of the 1-s range and furthermore the MW has a structure more flattened than the other systems having similar parameters. Besides, we propose a new criterion for the MW-like systems superseding the conventional ones such as major-minor axis ratio of the MW's DoS with a value of 0.183. Each satellite system has a specific orbital combination and thus has a particular distribution of its parameters (and thus flatness). The median of the distribution is set as the representative value of each system. And the representative value of the MW can be used as a new criterion for classifying the MW-like DoS. We reconstruct the orbital combination of the observed MW satellites using GAIA DR2 data and find the systems in the simulation that have representative values similar to the new criterion from the reconstructed MW system. This allows us a new interpretation on the rarity of MW-like DoS in cosmological simulations.

• 대한두개안면성형외과학회지
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• 제23권6호
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• pp.269-273
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• 2022

Naso-orbito-ethmoidal (NOE) fractures are complicated fractures of the mid-face. The treatment of NOE fractures is challenging and a comprehensive treatment strategy is required. We introduce a case of NOE fracture treated with open reduction and suspension sutures. A 28-year-old woman presented with a unilateral NOE fracture. To reduce the frontal process of the maxilla, a suspension suture was made by pulling the fragment using a double arm suture via a transcaruncular incision. The suture thread was placed in the horizontal plane. Another suspension suture on the inferior orbital rim assisted reduction procedure, and they passed through the overlying skin. The reduction alignment could be finely adjusted by tightening the transcutaneous suture threads while checking the degree of bone alignment through the subciliary incision. The two suture threads were suspended using a thermoplastic nasal splint. An additional skin incision on the medial canthal area, which would have resulted in a scar, could be avoided. Four months postoperatively, computed tomography showed an accurate and stable reduction. The patient was satisfied with her aesthetic appearance, and functional deficits were not present.

• 한국생산제조학회지
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• 제26권3호
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• pp.285-291
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• 2017

Micro-needles are used as transferring devices for sampling of tiny constitute substances from biological bodies. Typically, nickel is used as a coating to improve the rigidity of micro-needles. This study introduces the methodology to manufacture a WC needle with very high hardness and toughness. Micro-EDM technology was used to manufacture micro-needles with holes $130{\mu}m$ in diameter and $2300{\mu}m$ in length. A micro-needle was aligned to the micro-EDM electrode using a custom two degree-of-freedom alignment system. A three-step manufacturing technique was developed to drill a micro-hole using a WC electrode. In the first process, an electrode $105{\mu}m$ in diameter was used to make a hole. Electrodes of 90 and $105{\mu}m$ diameters were used in the second and third process, respectively. Consequently, a WC micro-needle with an inner hole of $135{\mu}m$ diameter, length of $2300{\mu}m$, and outer diameter of $300{\mu}m$ was developed.

• Carbon letters
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• 제15권2호
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• pp.142-145
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• 2014

Isotropic synthetic graphite scrap and phenolic resin were mixed, and the mixed powder was formed at 300 MPa to produce a green body. New bulk graphite was produced by carbonizing the green body at $700^{\circ}C$, and the bulk graphite thus produced was impregnated with resin and re-carbonized at $700^{\circ}C$. The bulk density of the bulk graphite was $1.29g/cm^3$, and the porosity of the open pores was 29.8%. After one impregnation, the density increased to $1.44g/cm^3$ while the porosity decreased to 25.2%. Differences in the pore distribution before and after impregnation were easily confirmed by observing the microstructure. In addition, by using an X-ray diffractometer, the degrees-of-alignment (Da) were obtained for one side perpendicular to the direction of compression molding of the bulk graphite (the "top-face"), and one side parallel to the direction of compression molding (the "side-face"). The anisotropy ratio calculated from the Da-values obtained was 1.13, which indicates comparatively good isotropy.

• 한국측량학회지
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• 제13권2호
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• pp.209-218
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• 1995

철도속도향상 계획은 미래에 있어 풍요로운 사회를 실현시키는데 중요한 역할을 담당하게 될 것이다. 열차 운행속도에 매우 큰 영향을 주는 선형 요소는 곡선구간으로서 이 구간에서는 열차의 주행성과 승객의 승차기분을 저해하는 요인을 줄이기 위해 완화곡선구간을 포함한 곡선부에 캔트 및 슬랙을 설치하게 되는데 이러한 값들은 열차의 종류가 다르기 때문에 균형적인 값을 사용하지 못하고 어느 정도 부족한 상태로서 유지되고 있다. 본 연구에서는 곡선반경별로 설정캔트량을 조사하여 부족캔트량에 대한 횡가속도를 산출하여 곡선부에서의 주행성을 검토하여 효과적인 곡선관리 방법을 제시하였으며 선형개량요소를 적용하여 속도향상 효과를 얻었다.