• Journal of Digital Convergence
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• v.17 no.10
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• pp.373-379
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• 2019

Polymethyl methacrylate (PMMA), a self-polymerizing resin for removable orthodontic devices, has been used as a dental orthodontic device for many years because of its advantages such as color stability, volume stability, and tissue compatibility. However, such a removable orthodontic device has a disadvantage that the longer the use in the oral cavity due to the low strength of the PMMA fracture of the orthodontic device resin in use. In this study, zinc nanoparticles (ZNP) were mixed with orthodontic PMMA to introduce strength effect. Rectangular samples ($1.4{\times}3.0{\times}19.0mm$) of orthodontic PMMA (0, 0.5, 1.0, 2.0 and 4.0%) containing ZNP were prepared. The finished specimen was tested for three-point bending strength at a speed of 1 mm / min, and the Vickers hardness was measured three times using a hardness tester. The surface roughness was measured with a surface roughness. As a result, the 3-point bending strength did not change significantly (p>0.05). Surface energy increased significantly. As a result, we successfully synthesized ZNP in this study and prepared the dispersed resin specimen for calibration. It will be possible to develop high-density dental orthodontic resins.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.3
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• pp.206-212
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• 2000

The guided wave mode conversion phenomena were investigated for the NDE of a plate-like structure with thickness variation. The ratios of reflection and transmission (R/T) were measured via the self-calibrating procedure which allows us to obtain experimental guided wave data in a more reliable way regardless of the coupling uncertainty between transducer & specimen. The results on R/T could be used to determine the thickness reduction of the structure. It was shown that not only the incident modes but also the converted ones need to be considered in the self-calibrating guided wave inspection to extract a reasonable correlation between experimental data & the thickness variation. Through this study, the potential of guided wave inspection as a quantitative NDE technique was explored based on the combined concept of self-calibration & multi-mode conversion in guided wave scattering problems.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.389-396
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• 2020

In order to obtain a good quality product, a proper verification of production/test facilities must be preceded before the quality conformity inspection of the product. Among the various production/test facilities, ATE is widely used in the civilian industry such as the automotive industry, aerospace industry, semiconductor industry today. In addition, ATE is actively used in the defense industry production and performance tests. This paper is the result of systematically verifying the Design Conformance of ATS which is ATE of military FM radio set using various methods. And It is expected to be a good reference at the present time when the design conformity verification procedure for ATE for military supplies is not documented.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.10
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• pp.91-98
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• 2007

This paper describes the development of the calibration system for a multi-axis force/moment sensor and its uncertainty evaluation. This calibration system can generate the continuous forces (${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$) and moments (${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$). Many kinds of multi-axis force/moment sensors in industries should be carried out the characteristic test or the calibration with the calibration system that can generate the forces and the moments. The calibration systems have been already developed are the disadvantages of the low capacity, the generation of step forces(10N, 20N ...) and step moments(1Nm, 2Nm ...) with weights, the high coasts in manufacture and so on. In this paper, the calibration system for a multi-axis force/moment sensor that can generate the continuous three forces and three moments was developed. Their ranges are $0{\sim}2000N$ in all force-directions and $0{\sim}400Nm$ in all moment-directions. And the system was evaluated in the expanded relative uncertainty. They were ${\pm}0.0004$ in all forces ${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$, and ${\pm}0.0004$ in all moments ${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.157-164
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• 2005

Two methods, the bin averaging method and least square method, are often used in calibrating wind turbine test sites. The objective of this work was to determine a better method to predict the wind speed at wind turbine installing point. The calibration was done at the test site on a complex terrain located in Daegwallyeong, Korea. It was performed for two different cases based on the IEC 61400-12 power performance measurement standard. The wind speeds averaged for 10 minutes ranged between 4 m/s and 16 m/s. The wind-direction bins of each meteorological mast were 10 degrees apart, and only the bins having data measured for more than 24 hours were employed for the test site calibration. For both cases, the two methods were found to yield almost same results which estimated real wind speed very closely.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.25-32
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• 1991

MCNP code was used to calculate conversion factor H(d)ma at the depths of 0.07 and 10mm within a water phantom recommended by IAEA and within a PMMA phantom required by the US dosimeter proficiency testing programmes. The calculations were performed for an expanded parrallel beam of monoenergetic photons of perpendicular incidence on one faces of the phantom. The results can be used as conversion factor in calibrating individual dosemeters in terms of the dose equivalent quantities defined directly in the phantom.

• Defense and Technology
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• no.5 s.279
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• pp.46-55
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• 2002

국과연 종합시험단은 지난해 12월 국가정밀기술진흥대회 계량.측정기 개발 부문에서 "정방향 스텝 동압력 교정장치 개발"로 최고의 상인 우수상(국무총리상)을 수상하였다. 국가 정밀기술진흥대회의 목적은 산업의 고도화에 기반이 되는 정밀측정 기술의 개발을 촉진시키고 정밀측정 능력을 향상시켜 산업의 품질 경쟁력을 높이며 새로운 계략측정기의 개발의욕을 고취시켜 계측기기의 대외 수입 의존도를 낮추어 가는데 있다. 1971년 제1회 대회가 시작된이래 지금까지 31회째 정밀기술대회가 개최되었다. 본 대회는 국가차원에서 실시되는 기술올림픽에 해당하는 권위와 역사를 가지는 대회로 산업자원부, 중소기업청 및 한국경제신문사가 후원하고, 한국계량측정협회가 매년 주최하고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.48-55
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• 2000

The design techniques of an asymmetric TEM (ATEM) cell for calibrating E/H filed probes are presented in this paper. The authors describe the techniques to obtain not only the arbitrary frequency and second resonant frequency, but also the test space with $\pm$2dB filed uniformity. We could design an ATEM cell that the measured data, electric filed distribution inside the cell, impedance matching and resonant frequencies, agree with the calculated results.

• Defense and Technology
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• no.4 s.278
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• pp.32-41
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• 2002

국과연 종합시험단은 지난해 12월 국가정밀기술진흥대회 계량.측정기 개발 부문에서 "정방향 스텝 동압력 교정장치 개발"로 최고의 상인 우수상(국무총리상)을 수상하였다. 국가 정밀기술진흥대회의 목적은 산업의 고도화에 기반이 되는 정밀측정 기술의 개발을 촉진시키고 정밀측정 능력을 향상시켜 산업의 품질 경쟁력을 높이며 새로운 계략측정기의 개발의욕을 고취시켜 계측기기의 대외 수입 의존도를 낮추어 가는데 있다. 1971년 제1회 대회가 시작된이래 지금까지 31회째 정밀기술대회가 개최되었다. 본 대회는 국가차원에서 실시되는 기술올림픽에 해당하는 권위와 역사를 가지는 대회로 산업자원부, 중소기업청 및 한국경제신문사가 후원하고, 한국계량측정협회가 매년 주최하고 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.309-314
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• 1996

가압 경수로형 원전 안전정지/ 안전 주입 변수와 관련된 계기는 관련 기술 기준에 따라 정기 보수시 교정이 이루어지면, 정지 신호를 모의 주입하여 물리량 검출기로 부터 원자로 정지집계 권선의 풀림시간까지의 총 응답 시간이 사고해석시 가정된 계통의 응답 지연시간이내에 들어 있는 지를 확인한다. 이 정지 신호에 응답하는 동적 보상기의 특성과 관련하여 설계과정에서 삽입된 근사화 오차에 대한 정략적인 평가가 이미 알려진 바 있고, 시간 응답 측정시 삽입되는 지연 요소로 인한 오차도 이에 포함시켜 분석한 바 있어 실제 교정시 정밀도 향상을 위하여 활용하고 있다. 이 논문을 통하여 원자로 정지계통의 응답시간 측정시 노 냉각수 평균 온도 변화율 동적 보상 미분-지연 카드에 모의입력으로 스텝신호를 주입할 경우, 이를 과도하게 큰 신호로 인식하여 매우 짧은 시간(1초 이내)에 응답되고, 스텝신호대신 1%P.U./초로 평균온도 변화율만을 주입할 경우, 보다 늦게 응답됨을 밝혔다. 따라서 모의 시험 방범에 있어서 입력 선택을 적합하게 하여야만 계통의 건전성을 응답시간으로 확인한 수 있는 데, 이에 적합한 모의 입력 방법을 제안하였다.