• Journal of the Korean Society of Radiology
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• v.3 no.4
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• pp.35-38
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• 2009

Flat-panel x-ray detectors using a phosphor and photoconductor material have been used for application in various medical modalities. In this study, the monte carlo simulation, optical and x-ray response characteristics were investigated in the conversion structure obtained by a columnar CsI:Na scintillation layer with a photosensitive amorphous selenium layer. Firstly, from the measurement of luminescent spectrum of CsI:Na and absorption spectrum of a-Se layer, the signal conversion characteristics are analysed. And also, the x-ray sensitivity is measured and compared with conventional a-Se($500{\mu}m$) as a function of electrical field. From the experimental result, the x-ray sensitivities of the CsI:Na($180{\mu}m$)/a-Se($30{\mu}m$) detector and the a-Se($500{\mu}m$) detector were $7.31nC/mR-cm^{2}$ and $3.95nC/mR-cm^{2}$at an electric field of $10V/{\mu}m$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.965-967
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• 2003

Czochralski pulling method에 의해 성장된 고농도 도핑 Nd:LSB의 광학적 특성을 조사하였다. 결정 성장조건에 의해 달라지는 space group은 지금까지 C2/c, R32, Cc와 C2등 4가지가 보고되었으며, 기본적으로 6방정계의 구조를 가지고 비선형 광학 결정으로서의 특성을 보였다. x선 회절 분석계를 이용하여 구조를 분석하였고, 도핑 농도에 따른 형광 수명의 변화, 분산곡선 특성을 조사하였다. 또한 흡수 및 저온 형광 스펙트럼을 이용하여 도핑 농도 및 space group의 변화에 따른 에너지 준위의 변화를 관찰하고 비교하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.344-344
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• 2007

본 연구에서는 X선 영상 검출기로의 적용을 위하여 $Gd_2O_3$:Eu 형광체 필름을 제작하여 X선에 대한 발광 특성을 분석하였다. $Gd_2O_3$:Eu는 저온 액상법을 이용하여 분말 형태로 제조한 후 Particle-in-binder (PIB)으로 필름 형태로 제작한 후, 도핑된 Europium(Eu)의 농도와 소결 온도에 따른 X선에 대한 발광 특성을 분석하였다. Photolumimescence (PL) spectrum에서 611nm에서 가장 높은 발광 효율을 나타내었으며, 입자의 크기가 줄어듦에 따라 610nm에서 새로운 peak가 형성 되었다. 또한 Eu의 농도에 따라서 발광 강도의 차이가 관찰되었는데, 5wt%의 도핑 농도에서 가장 높은 발광 효율을 나타냈으며, 도핑 농도에 매우 의존적인 결과를 나타냈다. 소결 온도에 따른 발광 특성 분석에서, $500^{\circ}C$에서 소결하였을 때는 623nm에서 강한 peak를 나타내는 단사정계상의 발광 peak는 거의 관찰되지 않았으나 소결 온도가 $700^{\circ}C$와 $900^{\circ}C$에서는 peak가 확인되었다. 이를 통해 $Gd_2O_3$ 모체가 대부분 입방 대칭 구조를 가지는 $Gd_2O_3$:Eu가 합성되었음을 확인할 수 있었다. 또한 소결 온도에 따른 발광 강도를 분석한 결과 $900^{\circ}C$에서 소결하였을 때 가장 높은 발광 강도를 나타냈다. Luminescent decay time 측정 결과에서 도핑된 Eu의 농도가 커질수록 Luminescent decay time이 짧아짐을 확인할 수 있었다.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.247-254
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• 1993

A simple and direct method is developed for the determination of light Elements in atmospheric particulates by X-ray fluorescence spectrometry. Calibration standards for the light elements such as Al, Mg, K, Ca, etc are prepared by filtering real atmospheric particulates over variable time and subsequently standardizing them by Inductively Coupled Plasma-Mass Spectrometry(ICP-MS) or Atomic Absorption Spectrophotometry(AAS) analysis. The validity of this calibration method is tested by analyzing more than 100 aerosol samples, collected at urban(Seoul) and rural(Padori) sites over a two year period with this method and then comparing them with those by other accuracy proven methods such as AAS or ICP-MS: for all metals tested the results showed reasonably good agreements (R $\geq$ 0.95).

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.21-29
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• 1989

The metals present in atmospheric particulate come from various sources; natural or anthropogenic. Among various metals Fe, Zn, Pb, Cu, and Mn are of particular concern in as much as they are not only present in large quantity, but toxic to human body. A simple, fast, and non-destructive analytical method for these metals in atmospheric particulate was developed and the analytical details were described herein. The method involves the measurements of X-ray fluorescence of sample contained in filters and comparing it with those for standards. The standard filters were prepared by applicating premeasured standard solution to the filters and then drying. The accuracy of the method was tested by analyzing standard reference materials and by independently analyzing samples using a different, previously accuracy-proven method, inductively coupled plasma atomic emission spectrometry, and comparing the results obtained. Analytical sensitivities and detection limits of the present method were 62.9, 178.2, 82.9, 146.1, 37.2, 120.3 cps/$\mug/cm^2$ and 39.0 35.6, 137.5, 125.9, 182.6, 72.8 $ng/cm^2$ for Fe, Zn, Pb, Cu, Mn, and Ni respectively. The method was applied to Seoul atmospheric particulate and some results were reported.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.415-417
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• 2003

CsI 형광체는 X선에 대한 분해능 및 변환효율이 우수한 물질이다. 최근 대면적 평판형 X선 영상검출기의 변환층으로 이용하기 위해 CsI 형광체의 대면적 제조에 대한 연구가 활발히 진행되고 있다. 본 논문은 진공 열증착법을 이용하여 증착속도(3, 3.8, $4.5\;{\mu}m/min$)에 따라 $20\;{\mu}m$ 두께의 CsI 필름을 제조하였고, XRD 및 SEM 분석을 통해 CsI 필름의 기하학적 구조를 조사하였다. 증착된 CsI 필름은 증착속도에 관계없이 복잡한 다결정 구조를 가지며, $3\;{\mu}m/min$의 증착속도에서 약 $1\;{\mu}m$ 크기로 needle-like 한 columnar structure를 가졌다. As results, about 3um/min evaporation rate formed as good geometry characteristics CsI layer.

• Journal of Conservation Science
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• v.37 no.2
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• pp.144-153
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• 2021

Gwanghwadang-Wonsam was designated as National Folklore Cultural Heritage No. 52 in 1979, it is in good condition. However, a problem is the attached a phoenix insignia badge that did not exist when it was designated recently. As it became known as the only purple Wonsam artifact with "phoenix insignia", raising the need for its conservation. In this regard, scientific analysis was required to correct misinformation about designated cultural assets and restore the original designated state by analyzing the history of the Gwanghwadang-Wonsam, other relics of the phoenix insignia and its making design patterns. An X-ray fluorescence analysis was used to confirm that the Phoenix insignia's metal threads were titanium-plated silver. Phoenix insignia using titanium-plated gold thread was not identified in Gwanghwadang-Wonsam photographs in 1986, and the TiN-type membrane plating method was used in various industries in the 1990s, which can be estimated to be attached in the early and mid-1990s. Especially, the scientific analysis results from the X-ray fluorescence analysis in this study provide key evidence for conservation processing. This study demonstrates the importance of investigating relics and similar artifacts in the conservation process of inherited relics and as a precedent for restoration that corrects misinformation about designated cultural properties.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.864-870
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• 2014

To propose a basis for the selection of personal dosimeters to measure radiation dose administration of radiation workers as a way to evaluate the usefulness dosimeter. For the dosimetry of the radiation workers 2012, during 1 year, 30 were radiation workers to measure personal dose. By personal exposure is measured cumulative dose, is investigated the performance of the TLD, PLD, OSLD. And comparing the measured value of each dosimeter dose and analyzed. Medical institutions, inspection work and quarterly confirmed the cumulative exposure dose of radiation workers. Using DAP and Ion-Chamber, to measure to compare TLD, PLD, OSLD dosimeter performance. A comparison of the directly through the X-ray dosimeter and The absolute value of the Ion-Chamber, OSLD more similar than in the TLD and PLD showed the dose values so the excellent ability to measure the results. Also in radiation generating area dose of radiation workers is higher than that in OSLD. Consequently, in terms of the individual exposure management OSLD is appropriated and beneficial than others.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.81-84
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• 2004

본 논문은 스크린 프린트 방식을 이용하여 두께 $18{\mu}m$의 ZnS:(Cu,Al) 필름을 제조하여 미세구조와 결정성을 분석하고 형광체로써의 특성을 평가하였다. 영상획득에는 포항 가속기 연구소의 싱크로트론을 이용하였으며 CMOS 영상 센서를 사용하여 DR의 간접방식을 구현하였다. 특성 평가를 위해 SEM 측정, 발광 강도 측정을 하였고, 단색광(Beam size $5mm{\times}2mm$)을 사용하여 test phantom 영상과 물고기 영상을 획득하였다. 획득한 영상의 평가를 위해서 test phantom 영상의 MTF 측정을 하였다 제조된 ZnS:(Cu,Al) 필름의 표면은 육방정계 구조를 가졌으며, 5lp/mm는 73.8%, 10lp/mm는 38.9%, 15lp/mm는 15.4%, 20lp/mm는 12.2%의 MTF를 가졌다. 물고기 영상을 통하여 ZnS:(Cu,Al) 필름을 이용한 고해상도 미세구조영상 획득의 가능성을 확인하였다.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.146-151
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• 2005

The coral is precious and organic gemstone. It is Beautifully Red color. Coral jewelry have been used for a long time in Asia. Especially in Korea, The Coral is an traditional and popular gemstone. It is significant to get the base data for the purpose of distinguishing natural coral from imitation coral by comparing about gemmological character in this study. Color, luster, transparency, streak color, refractive index, hardness, chemical reaction, ultraviolet fluorescence, specific gravity, observation of microscope and XRD analysis were conducted for identification of natural and imitation coral. As a result, natural coral has usually $CaCO_3$ composition and calcite structure. But, it is known that imitation coral impregnate calcic and dyeing materials with pigment. And they were distinguished also from not only XRD analysis but also a few simple experiments like specific gravity, refractive index and chemical reaction. Natural coral is harder and luster then imitation coral. In breaking method, the streak color is used certification.