• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.218-219
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• 2005

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.35-38
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• 2002

In this paper, for digital x-ray conversion receptor development studied by hybrid technology of based on CdZnTe. For this study, First searched fabricate method of CdZnTe x-ray receptor. Second, search the phosphor material & fabricate method for scintillator layer. Fabricated sample is analyzed with physical & electric measurement. This result is showed good SNR ratio hybrid thechnology with direct method & indirect method. In this paper offer the method can reduce the dark-current in the hybrid X-ray detector.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.360-362
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• 2018

본 논문에서는 X-ray 영상에서 척추 영역을 추출 및 분석하여 척추만곡도를 자동으로 측정하는 방법을 제안한다. 제안된 방법은 X-ray 영상에서 어깨뼈와 골반뼈 등과 같이 필요 없는 영역을 제거한 ROI(Region of Interest) 영역을 추출하고, 추출된 ROI 영역에서 척추 에지를 검출하기 위해 가우시안-라플라시안(Laplacian of Gaussian) 필터를 적용하여 척추 에지를 검출한다. 추출된 척추 영역을 척추의 Apex를 기준으로 Above Apex와 Below Apex 영역으로 구분하고 허프 변환(Hough Transform) 기법을 적용하여 두 영역에 대한 ($r,{\theta}$) 허프 공간을 구한다. ($r,{\theta}$) 허프 공간에서 척추만곡도 측정에 필요한 수평 직선만을 검출하기 위하여 수직 직선을 나타내는 교점들의 영역을 제거하여 척추만곡도 측정에 필요한 영역을 추출한다. 제안된 척추 추출 방법을 다양한 X-ray 영상을 대상으로 실험한 결과, 전문의가 척추만곡도를 효과적으로 측정하고 분석할 수 있는 척추 영역이 추출된 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.32-34
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• 2007

The X-ray projection system has long been used for steel-tube inspection and weld monitoring. The thickness of tubes and welded areas is based on the evaluation of radiographic shadow projections. The traditional tangential measurement estimates the distance of border lines of the projected wall shadows of a tube onto a radiographic image detector. The detected image in which although there is a variety of noise may be sectioned into several partitions according to its specific blocks. Imaging noise originates from most of elements of the system, such as shielding CCD camera, imaging screen, X-ray source, inspected object, electronic circuits and etc. The tangential projection incorrectness and noise influence on imaging quality. In this paper we first sectionalize the X-ray image on the basis of vertical contrast difference. And next functional and statistic analysis are carried on at each region. Geometrical distance and unsharpness of the edge caused by visual evaluation uncertainties are also discussed.

• Current Applied Physics
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• 제18권11호
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• pp.1196-1200
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• 2018

We have experimentally demonstrated circular polarization generation from linear polarized soft X-ray at synchrotron by adopting a thin magnetic film polarizer. Polarizer is composed of Co/Pt multilayer with a perpendicular magnetic anisotropy, which allows us to easily accommodate without needing any tilting angle into the measurement setup since the circular polarization is generated for the X-ray with normal incidence and transmission. Generated circular polarization is examined by observing magnetic domain features based on the X-ray magnetic circular dichroism, where~11% of circular component is estimated compared to the case of full circular polarization.

• 한국가시화정보학회지
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• 제4권2호
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• pp.69-75
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• 2006

The microbubbles were used in various fields, such as turbulent control, drag reduction, material science and life science. The X-ray PTV using X-ray micro-imaging technique was employed to mea-sure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}$=2.7mm) were tested. Due to the different refractive indices of water and air, phase contrast X-ray images clearly show the exact size and shape of over-lapped microbubbles. In all of the working fluids tested (deionized water, tap water, 0.01 and 0.10M NaCl solutions), the measured terminal velocity of the microbubbles rising through the solution was proportional to the square of the bubble diameter. The rising velocity was increased with increasing mole concentration. The microbubble can be useful as contrast agent or tracer in life science and biology. The X-ray PTV technique should be able to extract useful information on the behavior of various bio/microscale fluid flows that are not amenable to analysis using conventional methods.

• 분석과학
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• 제19권5호
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• pp.407-414
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• 2006

An X-ray diffractometer for spatially resolved X-ray diffraction measurements was developed to identify phase in the narrow (micron-scaled) region of high burn-up fuels and some nuclear materials. The micro-XRD was composed of an X-ray microbeam alignment system and a sample micro translation system instead of a normal slit and a fixed sample stage in a commercial XRD. The X-ray microbeam alignment system was fabricated with a microbeam concentrator having two Ni deposited mirrors, a vertical positioner, and a tilt table for the generation of a concentrated microbeam. The sample micro translation system was made with a sample holder and a horizontal translator, allowing movement of a specimen at $5{\mu}m$ steps. The angular intensity profile of the microbeam generated through a concentrator was symmetric and not distorted. The size of the microbeam was $4,000{\times}20{\mu}m$ and the spatial resolution of the beam was $47{\mu}m$ at the sample position. When the diffraction peaks were measured for a $UO_2$ pellet specimen by this system, the reproducibility ($2{\Theta}={\pm}0.01^{\circ}$) of the peaks was as good as a conventional X-ray diffractometer. For the cross section of oxidized titanium metal, not only $TiO_2$ in an outer layer but also TiO near an oxide-metal interface was observed.

• 한국의학물리학회지:의학물리
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• 제1권1호
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• pp.69-73
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• 1990

Dosimetric measurement of an asymmetric collimator system was performed, using water phantom system for 4MV X-ray linear accelerator. We have studied the system of dose calculation with those measured result. We compared the field size factor and the percent depth dose for asymmetric collimator to those factor for symmetric fields. The results show that we can use symmetric field data directly within 1% error, if we consider the off axis ratio(OAR).

• 한국진공학회지
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• 제17권3호
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• pp.234-239
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• 2008

휴대용 XRF (X-Ray Fluorescence) 장치에 적용할 수 있는 40 kV용 투과 양극형 W-Target tube와 Rh-Target tube를 개발하고 특성을 조사하였다. 특성 x-ray의 에너지와 연속 x-ray의 선량특성은 알려진 결과와 잘 일치함을 확인하였고, 최대 선량을 추출하기 위한 양극금속 박막의 최적 두께는 W-target tube의 경우 약 $2.6{\mu}m$, Rh-target tube의 경우 약 $2.7{\mu}m$ 임을 밝혀내었다. 또한 관전압 40 kV, 관전류 $60{\mu}A$로 30분 동안 연속적으로 작동시켰을 때 양극에서의 온도는 $50^{\circ}C$를 넘지 않아 휴대용 XRF장치에 적용할 수 있음을 확인하였다.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.248-261
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• 1999

The fatigue life of mechanical components and structures has been influenced by mechanical, material and environmental conditions. It is important to search out the load type and size for accurate cause of fracture at the damaged surface of material. The fractographic method by x-ray diffraction can utilize residual stress $\sigma$_r and half-value breadth B and find out the types and the mechanical conditions of fracture. This study showed the relationship between fracture mechanical parameters $\Delta$K, $K_{max}$ and X-ray residual stress $\sigma$_r for normalized SS41 steel with homogeneous crystal structure and M.E.F. dual phase steel(martensite encapsulated islands of ferrite). The fatigue crack propagation tests were carried out under stress ratios 0.1 and 0.5. The x-ray diffraction technique according to crack propatation direction was applied to fatigue fractured surface. Residual stress $\sigma$_r was independent on stress ratios by arrangement of $\Delta$K. The equation of $\sigma$_r$\Delta$K was established by the experimental data. Therefore, fracture mechanical parameters can be estimated can be estimated by the measurement of X-ray parameters.