• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.36-39
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• 2000

A small electrical potential difference which appears on any solid body when subjected to illumination by a modulated light beam generated by laser is called photocharge voltage(PCV)[1,2]. This voltage is proportional to the induced change in the surface electrical charge and is capacitatively measured on various materials such as conductors, semiconductors, ceramics, dielectrics and biological objects. The amplitude of the detected signal depends on the type of material under investigation, and on the surface properties of the sample. In photocharge voltage spectroscopy measurements[3], the sample is illuminated by both a steady state monochromatic bias light and the pulsed laser. The monochromatic light is used to created a variation in the steady state population of trap levels in the surface and space charge region of semiconductor samples which does result in a change in the measured voltage. Using this technique the spatial variation of PCV can be utilized to evaluate the surface conditions of the sample and the variation of the PCV due to the monochromatic bias light are utilized to characterize the surface states. A qualitative analysis of the proposed measurement is present along with experimental results performed on amorphous silicon samples. The deposition temperature was varied in order to obtain samples with different structural, optical and electronic properties and measurements are related to the defect density in amorphous thin film.

• 한국기계기술학회지
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• 제13권1호
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• pp.23-29
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• 2011

The measurement of ice properties such as thickness, strength are important to know the performance of the ice breaking vessel. The measuring equipment of ice properties and methods are summarized in this paper. The actual measured data are also described. The strength of ice at Svalbard area on April 2010 is much stronger than the Chukchi Sea on August 2010. The mean strength of Svalbard is about 500 kPa and one of Chukchi Sea is 250 kPa. The first sea trial in Arctic sea using Araon was carried out in the Chukchi Sea. The power and speed was also measured to check the ship performance in ice. The speed was measured from GPS(Global Positioning System) and engine power was recorded from DPS(Dynamic Positioning system) of Araon. The design target of Araon in level ice is 3 knots in 1m thickness and 630 kPa flexible strength but mean speed in Chuckchi sea is 3.98 knots when 6.6 MW engine power, 2.4m ice thickness and 250 kPa strength. This results comes from the difference of ice types and the weak flexible strength of ice but it will be a good information to know the performance of Araon in similar ice condition.

• 여성건강간호학회지
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• 제27권2호
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• pp.69-74
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• 2021

측정도구의 구조타당도는 내용타당도 이후 가장 먼저 수행되어야 할 측정 속성이다. 이를 위해 국내 간호학에서는 주로 CFA를 사용하는데, CFA로 얻을 수 없는 정보들을 제시하는 IRT/라쉬 분석도 같이 적용해 볼 것을 추천한다. 구조타당도 이외에 내적일관성 및 교차문화타당도/측정동일성 또한 측정도구의 내적구조를 확인하기 위한 것이다. 국내 간호학 측정도구 연구에서 교차문화타당도/측정동일성에 대한 검증은 거의 찾아볼 수 없는 상황이다. 따라서 앞으로는 이에 대한 평가도 시행되기를 바란다.

• 한국의학물리학회지:의학물리
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• 제35권1호
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• pp.10-15
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• 2024

Purpose: This study aimed to comprehensively investigate the diverse characteristics of a novel commercial bolus, CLEANBOLUS-WHITE (CBW), to ascertain its suitability for clinical application. Methods: The evaluation of CBW encompassed both physical and biological assessments. Physical parameters such as mass density and shore hardness were measured alongside analyses of element composition. Biological evaluations included assessments for skin irritation and cytotoxicity. Dosimetric properties were examined by calculating surface dose and beam quality using a treatment planning system (TPS). Additionally, doses were measured at maximum and reference depths, and the results were compared with those obtained using a solid water phantom. The effect of air gap on dose measurement was also investigated by comparing measured doses on the RANDO phantom, under the bolus, with doses calculated from the TPS. Results: Biological evaluation confirmed that CBW is non-cytotoxic, nonirritant, and non-sensitizing. The bolus exhibited a mass density of 1.02 g/cm³ and 14 shore 00. Dosimetric evaluations revealed that using the 0.5 cm CBW resulted in less than a 1% difference compared to using the solid water phantom. Furthermore, beam quality calculations in the TPS indicated increased surface dose with the bolus. The air gap effect on dose measurement was deemed negligible, with a difference of approximately 1% between calculated and measured doses, aligning with measurement uncertainty. Conclusions: CBW demonstrates outstanding properties for clinical utilization. The dosimetric evaluation underscores a strong agreement between calculated and measured doses, validating its reliability in both planning and clinical settings.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.733-737
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• 2001

Heat generated from the electronic parts in PDP is undesirable physical properties. To attain optimal arrangement of the electronic parts in PDP, thermal flows in PDP should be analyzed. PIV measurement has been made to quantify the characteristics of the inner flows and outer flows of an actual PDP. The quantity of heat flux from PDP has been estimated using the PIV results. Measurement system consists of Ar-ion laser, CCD camera and an image grabber installed on a host computer.

• 한국결정학회지
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• 제12권2호
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• pp.65-91
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• 2001

Sawyer-Tower 회로를 이용한 강유전 이력곡선의 측정에서 직류 누설성분에 의한 오차요인을 검토하고 그 해결책을 제안하였다. 강유전체 시편에 존재하는 직류 누설성분에 의한 잔류분극과 항전계는 항상 과대 평가될 수 있는 위험성이 있음을 알 수 있었으며 이러한 오차는 직류누설성분이 크고 측정시간이 길수록 심화되었다. Sawyer-Tower 회로를 이용한 강유전 이력곡선과 함께 보완적으로 활용할 수 있는 전류이력곡선을 새롭게 제안하였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.164-169
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• 2000

The remote measurement system(RMS) as a new experimental method is limited in its application to crack measurements at elevated temperatures because of the oxide layer on the specimen surface. Since TiAlN and Cr coating layers have a high resistance to oxidation and wear, this paper proposed a TiAlN and Cr coating technique for specimens to facilitate the measurement of crack growth behavior using RMS. To investigate the effects of the coating layer, tension and fatigue tests were carried out at room temperature and at 538$^{\circ}C$, using specimens of 1Cr-1Mo-0.25V steel. From the experimental results, it was found that the mechanical properties of the TiAlN and Cr coated specimens were similar to those of the substrate. Accordingly, the TiAlN and Cr coated layer had hardly any influence on the fatigue crack propagation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.252-257
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• 1991

This paper proposed that the eddy-current measurement method can be used a means of in-process measuring the hardening depth in Laser surface treatment process. Also, this paper deal with the numerical analysis of magnetic flux distribution and experimental result of measurement. In Laser heat treatment process of steels, a thin layer of the substrate is rapidly heated to austenitizing temperature and subsequently cooled at a very fast rate due to the self-quenching by heat conduction into the bulk body, to produce a martensite structure which have low magnetic permeability. The eddy-current measurement method depends on the properties of material to be measured such as electric conductivity, magnetic permeability and geometry. In this paper, the hardening depth was measured by detecting relevant magnetic permeability changes caused by heat treatment of steels.

• 대한기계학회논문집
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• 제18권4호
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• pp.816-825
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• 1994

The purpose of this study is to develop the non-destructive material evaluation method of aluminum alloy base metal matrix composite(MMC) by ultrasonics. Five aluminum base MMC specimens were fabricated in which the fractional ratios of fiber were changed from 0% to 31%. Relations among acoustic properties, microstructural features and elastic constant were compared. The ultrasonic velocity method was useful for nondestructive elastic constant measurement of composite materials, since the method had as same accuracy as conventional strain measurement method. Furthermore, velocity, attenuation and backscattering behaviors for each specimen also related to fractional ratio of fiber and these relations could utilize ultrasonic non-destructive evaluation of fiber structure in MMC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.354-357
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• 2001

The residual DC properties in the in-plane switching (IFS) liquid crystal displays(LCDs) which have different concentrations of cynao NLCs and different resistivities of fluorine NLCs were studied. We also propose a new residual DC measurement method, named 'light minimum/maximum method'. We confirmed the precision of residual DC measurement by light minimum/maximum method compared with the flicker minimizing method and found that new measurement method of residual DC is better than that of the conventional flicker minimizing method since the resolution level of measurements is in 0.1V