• 한국안광학회지
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• 제11권4호
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• pp.317-322
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• 2006

본 연구는 굴절이상을 가진 사람 중 난시안이고 스스로 난시량을 알고 있는 사람에 한하여 주로 사용하는 시력교정 기구와 그것에 대한 만족도를 설문 조사하여 분석하였다. 설문 조사 대상자 46명중 시력 교정 수단으로 안경만을 사용하는 사람 11명 외에 35명의 콘택트렌즈 사용자들의 장기간 사용기간에 따라 발생하는 문제점을 경험한 사람이 25명이었고, 시력교정 상태에 매우 만족 외의 항목을 선택한 사람이 대부분을 차지하였다. 만족하지 못한 이유로는 미교정 난시, 잘못된 처방, 잘못된 Base Curve, 렌즈의 사용주기 경과 등이 있었다.

• Tribology and Lubricants
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• 제36권5호
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• pp.262-266
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• 2020

Herein, we present a numerical investigation of wear analysis of sliding systems with a constant speed subjected to Archard's wear law. For this investigation, we compared two methods: eigen-wear analysis and adaptive meshing technique. The eigen-wear analysis is advantageous to predict the evolution of contact pressure due to wear using the initial contact pressure and contact stiffness. The adaptive meshing technique in finite element analysis is employed to obtain transient wear behavior, which needs significant computational resources. From the eigen-wear analysis, we can determine the appropriate element size required for finite element analysis and the time increment required for wear evolution by a dimensionless variable above a certain value. Since the prediction of wear depends on the maximum contact pressure, the finite element model should have a reasonable representation of the maximum contact pressure. The maximum contact pressure and wear amount according to this dimensionless variable shows that the number of fine meshes in the contact area contributes more to the accuracy of the wear analysis, and the time increment is less sensitive when the number of contact nodes is significantly larger. The results derived from a two-dimensional wear model can be applied to a three-dimensional wear model.

• Tribology and Lubricants
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• 제15권2호
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• pp.164-170
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• 1999

Gerotor is widely used as a hydraulic pump or motor, by virtue of its volume changing ability. Performance deterioration of a gerotor hydraulic motor mainly due to the wear come from the contact between inner rotor with trochoidal curve and outer rotor with circular arc profile. This research covers the basic investigation about the contact forces of a gerotor hydraulic motor using analytic method. The influence of the eccentricity and the radius of circular arc teeth on the contact stress was evaluated.

• Pediatric Infection and Vaccine
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• 제23권2호
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• pp.94-101
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• 2016

목적: 대학병원에 근무하던 중 활동성 폐결핵으로 진단된 전공의에게 노출된 의료종사자들에 대하여 실시한 접촉자 조사의 결과를 보고한다. 방법: 활동성 폐결핵 환자와 밀접한 접촉을 한 사람(접촉자) 101명 중 89명이 접촉자 조사에 응하여 조사를 받았다. 1차 접촉자 조사는 지표환자의 증상 개시 후 30일경에, 2차 조사는 1차 조사 10주 후에 기침, 발열, 인후통, 체중 감소와 같은 임상증상 확인 및 단순흉부촬영과 함께 결핵반응검사(Tuberculin skin test, TST)/QuantiFERON-TB Gold (QFT-G) 2단계 검사법을 시행하였다. 결과: 1차 TST 양성자는 34명(38.2%)이었고, TST 양성자 중 35세 이하 접촉자에서 시행한 QFT-G 양성률은 37.5% (6/16)이었다. 1차 TST 음성 대상자 41명에게서 시행한 2차 TST에서 17명(41.5%)이 양전을 보였고 그들 중 시행한 QFT-G 검사에서 3명(17.6%)이 양성이었다. 활동성 결핵으로 진단된 접촉자는 없었으며 지표환자에 노출되어 발생한 결핵 전파율은 2단계 검사법으로는 7.3% (3/41)였고, TST 진단법으로는 41.5% (17/41)였다. 결론: 국내에서 처음 보고되는 병원 내 결핵 접촉자 조사 연구로서 LTBI 발생률이 그 진단 기법에 따라 달랐으며 따라서 앞으로 발생할 수 있는 의료종사자들에 대한 병원 내 결핵 접촉자 조사를 위해 조직적이고 실용적인 가이드라인이 필요할 것이다.

• Structural Engineering and Mechanics
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• 제3권3호
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• pp.289-297
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• 1995

A finite element algorithm for consideration of contact constraints is presented. It is characterized by introducing the geometric constraints, resulting from contact conditions, directly into the algebraic system of equations for the incremental displacements of an incremental iterative solution procedure. The usefulness of the proposed algorithm for efficient solutions of contact problems involving large displacements and large strains is demonstrated in the numerical investigation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 토목섬유 학술발표회 논문집
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• pp.115-122
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• 1998

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2415-2418
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• 2014

In this report, the contact resistance between "electrode" and "lead" is investigated for reasonable measurements of samples' resistance in a polypyrrole (PPy) nanowire device. The sample's resistance, including "electrode-lead" contact resistance, shows a decrease as force applied to the interface increases. Moreover, the sample's resistance becomes reasonably similar to, or lower than, values calculated by resistivity of PPy reported in previous studies. The decrease of electrode-lead contact resistance by increasing the applying force was analyzed by using Holm theory: the general equation of relation between contact resistance ($R_H$) of two-metal thin films and contact force ($R_H{\propto}1/\sqrt{F}$). The present investigation can guide a reliable way to minimize electrode-lead contact resistance for reasonable characterization of nanomaterials in a microelectrode device; 80% of the maximum applying force to the junction without deformation of the apparatus shows reasonable values without experimental error.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 추계학술대회 논문집
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• pp.157-164
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• 1994

Finite element analysis of material deformation is successfully utilized to understand metal forming processes such as forging, extrusion and deep drawing. However, such analysis involves contact problems; a free node touches a die surface and a contact node slips along the die surface. In the present investigation, appropriate contact algorithms were developed assuming that a three dimensional surface can be divided into bilinear patches and that nodal velocities are linear during an incremental time. The algorithms were coded into a computer program and tested for a simple surface. Comparison of the test result with that obtained from a commercial code is presented and discussed.

• 대한수학회논문집
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• 제35권4호
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• pp.1283-1297
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• 2020

The goal of this paper is the introduction of hyper generalized 𝜙-recurrent (k, 𝜇)-contact metric manifolds and of quasi generalized 𝜙-recurrent (k, 𝜇)-contact metric manifolds, and the investigation of their properties. Their existence is guaranteed by examples.

• Transactions on Electrical and Electronic Materials
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• 제16권3호
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• pp.139-141
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• 2015

Contact resistance of interface between the channel layers and various S/D electrodes was investigated by transmission line method. Different electrodes such as Ti/Au, a-IZO, and multilayer of a-IGZO/Ag/a-IGZO were compared in terms of contact resistance, using the transmission line model. The a-IGZO TFTs with a-IGZO/Ag/a-IGZO of S/D electrodes showed good performance and low contact resistance due to the homo-junction with channel layer.