• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.208-213
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• 1999

We proposed a new technique to precisely calibrate the angle of incidence in spectroscopic ellipsometer. The proposed technique can be useful to the thickness measurement of semiconductor thin films and optical thin films. The usefulness has been confirmed experimentally. We cut a block of optical glass into two pieces and made a prism as well as a slab using each piece. The apex angle and the angle of the minimum deviation of prism were measured. From these angles, the refractive index of glass material was calculated. From the analysis of the spectro-ellipsometric data collected near Brewster's angle, we could not only determine the error in the angle of incidence in the spectroscopic ellipsometer, but also calibrated the angle of incidence to the accuracy of 0.01 degree.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.451-455
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• 2003

최근 LCD제품은 고유한 특장인 경박단소가 요구되면서, 기존의 Back Light Unit(BLU) 로는 대응할 수 없는 사양으로 진화되고 있다. 기존과 동일한 설계개념으로 접근시에 시장에서 요구되는 중량, 두께, 휘도의 사양을 만족시킬 수 없으며, BLU의 주요광원인 CCFL(Cold Cathod Fluorescent Lamp)의 휘도 개선 또 한 한계에 다다르고 있다. 따라서 앞으로의 BLU 의 고성능화는 최적화, 고효율화로의 개발 전개가 예상되며, LCD의 고해상도에 따른 투과율 저하를 보상하기 위한 고품질 BLU의 개발이 시급한 상황이다. 본 연구에서는 이러한 BLU의 고효율화, 고품질화를 달성하기 위한 고성능 도광판 개발과 관련하여, 실물 제작에 앞서 광학시뮬레이션을 통한 이론적 접근을 수행하였다. 연구 결과, 상측에서 정각 $90^{\circ}$ 에 높이 $50{\mu}m$ 하측에서 정각 $80^{\circ}$ 높이 $28{\mu}m$일때 평균조도가 71.52W/m^2 구현됨을 알 수 있다. 이 결과를 바탕으로 통상의 인쇄 방식 도광판에 비해서 약 20% 정도의 휘도향상이 가능함을 알 수 있었다. 또한 차후 본 결과를 바탕으로 한 실물 제작을 통해 설계 시뮬레이션 결과와의 비교를 통해서 정확한 예측이 가능한 시스템을 구현함을 목적으로 하였다.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.5
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• pp.3-11
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• 2018

Since the tensegrity structure is flexible and variable, the study on the mobility to the tensegrity has been conducted. However, it is difficult to apply the tensegrity to the architecture field due to several limits. This paper describes the methodology for the analysis of the shape change process of single prism tensegrity structure as an initial study. To apply the tensegrity structure to the architectural field, the assemblage and mathematical formulation procedures of the single prism tensegrity structures are carried out. And single prism tensegrity are presented to the computational strategies for simulate the shape change of those structures. Next, the investigation of structural behaviors through various cases of target displacements is described. Also, the summary of these methods in algorithms is illustrated. As a result it is confirmed that the single prism tensegrity structure model converges 99% on average to a given target node by using the proposed algorithm. Therefore, it is confirmed that the proposed algorithm and program are suitable for shape change analysis of single prism tensegrity structure model.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.2
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• pp.127-136
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• 2020

Prism compressive strength is the most influential parameter to evaluate the seismic performance of non-structural concrete brick masonry walls, and is affected by the practice and workmanship of masonry workers. This study experimentally investigates the influence of workmanship on prism compressive strength throughout the compressive test with prism specimens constructed according to masonry workmanship. To do this, the workmanship is categorized into good, fair, and poor conditions which are statistically evaluated with thickness and indentation depth of bed-joints. Then, the effect of workmanship on the structural properties of masonry prisms is evaluated by investigating relations between properties such as their compressive strength, elastic modulus and numerical parameters such as thickness, filling of bed-joints. This study demonstrates that the indentation depth is more important parameter for structural properties of masonry prisms and masonry prisms with loss in bed-joint area less than of 7% can be in fair condition.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.193-200
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• 2006

We investigated the visual analysis of the far distance phoria for 83 subjects who have emmetropia or myopia eyes, using the graphic method, and determined new norms. We got the following results from these experiments. 1. The measured norm of far distance phoria is $1.12{\Delta}$, exophoria, the that of near distance phoria is $0.50{\Delta}$, exophoria, the that of negative relative convergence at far distance(N.R.C.) is ${\times}$/11/5, the that of positive relative convergence at far distance(P.R.C.) is 10/20/8, the that negative relative convergence at near distance(N.R.C.) is 11/21/5, the that of positive relative convergence at near(P.R.C.) is 10/20/8, the that of negative relative accommodation(N.R.A.) is +2.54D, and the that of positive relative accommodation(P.R.A.) is -2.60D, respectively. We know from theses results that the measured norms of far distancet phoria is higher than Morgan's norms, while those of near distance phoria are lower than Morgan's norms. 2. We also know from these experiments that Morgan's norms are closely related to A, B, and C groups and Morgan's criterion can more usefully apply to the visual analysis. 3. In Sheard's criterion and Percival's criterion, the prism prescription is occurred when the exophoria of the far-point phoria is over $7{\sim}9{\Delta}$, and the esophoria of that is over $4{\sim}6{\Delta}$.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.13-18
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• 2003

We did the comparison research about three different methods of measuring horizontal phoria and vertical phoria which are Von Graefe test, Maddox Rod test and polarizing lens test. The inspection was don with the subjective method of refraction about normal 63 subjects aged from 20 to 28 years old. The analysis of date resulted in as follows : 1. Using Von Graefe Horizontal phoria Measurement, they were measured 5% for orthpharia, 51% for exophoria and 44% for esophoria. 2. Using Von Graefe vertical phoria Measurement, they were measured 68% for orthphoria, 20% for left hypophoria against the right and 12% for left hyperphoria against the right. 3. Using Maddox Rod Horizontal phoria Measurement, they were measured 7% for orthphoria, 49% for exophoria and 44% for esophoria. 4. Using Maddox Rod vertical phoria Measurement, they were measured 70% for orthphoria, 19% for left hypophoria against the right and 11% for left hyperphoria against the right. 5. Using Polarizing Horizontal phoria Measurement, they were measured 10% for orthphoria, 49% for exophoria and 41% for esophoria. 6. Using Polarizing vertical phoria Measurement, they were measured 92% for orthpharia, 5% for left hypophoria against the right and 3% for left hyperphoria against the right.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.155-160
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• 2010

Purpose: The purpose of this study was to evaluate how phoria variations would vary with head positions, as well as to review the need to differentiate prism placement over either eye in a relation to the imbalance of the extraocular muscle. Methods: This study was carried out with 44 males (88 eyes) and 16 females (32 eyes) aged between 20 and 30. For all subjects, testings were performed using cover test, subjective refraction, phoria and vergence test. To analyze phoria variations comparatively for the head tilt test and the face turn test, phoria deviation were measured using the von Graefe. Results: For the phoria variation related with head tilt and face turn, a significant difference was observed in the group judged to be abnormal on the horizontal phoria of Morgan' norm (p<0.05); especially in patients who needed near prescription of Sheard's criterion, a higher variation was observed (p<0.05). The abnormal group was composed of patients who needed distance prescription of Sheard's criterion and ones who did not need the prescription, all of whom showed phoria variations, but the mean value was less than the near. Conclusions: With regard to the head tilt and face turn related phoria level, the patients who needed near horizontal prism prescription of Sheard's criterion showed a remarkably higher variation. Altogether, it is deemed to check whether extraocular muscles are ill-balanced in both eyes previously to determine the prism power on phoria level to the end that each of prism powers may be accurately determined.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.49.1-49.1
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• 2011

집광채광 설비는 건축물의 조명에너지 절감 및 자연광의 실내 유입을 위해 적용 가능한 태양에너지설비로써 다른 신 재생 에너지 설비와 다르게 연간에너지생산에 대한 정량적 데이터가 아직까지 부재하다. 집광채광 설비의 설치효과를 판단하기 위해서는 집광채광 설비 설치에 따른 연간 에너지생산량 산출이 필요하며, 이를 위해서는 각 구성부분(집광부, 전송부 및 산광부)의 광전송 효율에 대한 데이터가 구축되어야 한다. 본 연구는 집광채광 설비의 효율 분석에 관한 첫 번째 단계로써 외부광속에 대한 집광부 통과 직후의 내부광속의 비율을 예측하였다. 국내에 보급된 집광채광 설비는 대부분 프리즘형과 광덕트형이며, 우선적으로 집광부 입사면의 경사각과 방위각이 다양하여 내부광속 산출방법론이 매우 복잡한 프리즘형을 분석대상으로 삼았다. 전일사량, 외부조도 및 집광부 내부조도가 측정되었으며, 외부광속으로부터 내부광속을 산출하는 공식을 유도하기 위해 천공상태에 따라 전일사량 측정치가 직산분리 되었다. Perez model과 Liu and Jordon에 의해 제시된 계산식과 입사면 및 집광부 면적을 고려하여 수평면 외부조도 측정치로부터 외부광속이 그리고 내부조도로부터 내부광속이 산출되었다. 입사면의 투과율이 동일하다는 전제 하에 천공상태에 따른 태양광 투과 비율을 도출한 결과, 담천공(Kt ${\leq}$ 0.3)에서 0.39, 부분담천공(0.3${\geq}$ 0.78)에서 1.0으로 나타났다. 도출된 투과비율을 외부광속에 적용하여 내부광속을 계산한 결과치와 측정치는 약 ${\pm}9%$ 정도의 차이를 보였다. 연간 기상데이터에 위와 같은 방법론이 적용되면 프리즘형 집광부의 연간 내부광속이 산출될 수 있다. 또한 기존 연구에서 제시된 발광효율 산출식과 일사 파장에 따른 시감도를 고려하면 매 시간별 외부조도도 산출이 가능하다. 일사량 측정치와 외부조도 측정치 사이의 상관관계를 분석한 결과 결정계수 $R^2$이 0.99인데 반해 일사량 측정치와 외부조도 계산치 사이의 상관관계 결정계수는 0.95로 측정치 보다 약간 작은 값을 갖는다. 이렇게 산출된 외부조도는 각 입사면의 면적을 반영하여 외부광속으로 변환되고, 앞서 산출된 천공상태별 투과비율이 적용됨으로써 내부광속이 도출될 수 있다. 이와 같은 집광부에 대한 연구를 바탕으로 향후 전송부와 산광부 효율을 도출하고 궁극적으로 집광채광 설비를 통해 실내에 전달되는 연간 빛에너지를 예측할 수 있을 것이다. 또한 본 연구의 방법론은 다른 형태의 집광채광 설비에도 적용이 가능할 것으로 판단되며, 국내 집광채광 설비의 연간 에너지생산량에 대한 폭 넓은 데이터 구축이 가능할 것으로 기대된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.87-98
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• 2011

Clay bricks with lime mortar are recently popular since they are eco- and environment-friendly construction material being capable of air flow and moisture movement. However, there is little study on those of clay brick an lime mortar while relatively many researches on the structural characteristics of concrete bricks with cement mortar are available in Korea. Furthermore, the current Korean Building Code of masonry structures was established on the base of the Foreign Codes which does not reflect Korean masonry construction circumstance, such as material characteristics and section properties. To overcome these problems, experiments of masonry structures constructed using clay bricks with lime mortar were carried out to evaluate their structural characteristics such as, prism compressive strength, adhesive strength and diagonal tensile(shear) strength. Also this research compares the mechanical characteristics between clay bricks with lime mortar and concrete bricks with cement mortar to provide information that will be used for revisions of the domestic standards for masonry structures. As masonry structures constructed with clay bricks and lime mortar show different aspects over the ones constructed with concrete bricks and cement mortar, we suggest estimation equation of prism compressive strength and diagonal tensile strength on masonry structures constructed with clay bricks and lime mortar.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.617-618
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• 2008