• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.26.2-26.2
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• 2007

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.05a
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• pp.101-101
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• 2002

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.18-18
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• 1993

• Proceedings of the Korean Vacuum Society Conference
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• 1993.02a
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• pp.112-112
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• 1993

• Journal of the Korean Society of Radiology
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• v.2 no.2
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• pp.23-30
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• 2008

X-ray microscopy with synchrotron radiation(SR) might be a useful tool for novel x-ray imaging in the clinical and laboratory settings. Microscopically, it enables us to observe detailed structure of animal organs samples with a great magnification power and an excellent resolution. The phase contrast mechanisms in image by X-ray are described. The phase-contrast X-ray imaging with SR from in-vivo and in-vitro mouse tail, rat nerve and rat lung were obtained with an 8 KeV monochromatic beam. The visual image was magnified using 10x microscope objective lens and captured using an digital CCD camera. The results showed more structural details and high resolution images with SR imaging system than conventional X-ray radiography system. The SR imaging system may have a potential for imaging in biological researches, material applications and clinical radiography.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.619-619
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• 2013

The interfacial state between $Ta_2O_5$ and a Si substrate during the growth of $Ta_2O_5$ films by atomic layer deposition (ALD) was investigated using in-situ synchrotron radiation photoemission spectroscopy (SRPES). A newly synthesized liquid precursor Ta($N^tBu$) $(dmamp)_2Me$ was used as the metal precursor, with Ar as a purging gas and $H_2O$ as the oxidant source. After each half reaction cycle, samples were analyzed using in-situ SRPES under ultrahigh vacuum at room temperature. SRPES analysis revealed that Ta suboxide and Si dioxide were formed at the initial stages of $Ta_2O_5$ growth. However, the Ta suboxide states almostdisappeared as the ALD cycles progressed. Consequently, the $Ta^{5+}$ state, which corresponds with the stoichiometric $Ta_2O_5$, only appeared after 4.0 cycles. Additionally, tantalum silicate was not detected at the interfacial states between $Ta_2O_5$ and Si. The measured valence band offset between $Ta_2O_5$ and the Si substrate was 3.22 eV after 3.0 cycles.

• Journal of Conservation Science
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• v.36 no.1
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• pp.1-14
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• 2020

This study investigates the crystallinity distribution of ancient silk. Owing to the inherent multi-hierarchical structure of silk protein and the complicated structural changes that occur due to various burial environments, it is challenging but worthwhile to study ancient silk ageing behavior, which is based on the fact that ageing begins with a single fiber and then spreads to a whole fabric. Crystallinity was one of the most effective indicators found to reveal the ageing status of silk. Therefore, a synchrotron radiation-based X-ray diffraction(SR-XRD) method was employed to study the crystallinity distribution of single fibers of ancient silk unearthed from seven archaeological sites in China from historical periods including the warring states, Han dynasty, Song dynasty, and Ming dynasty. In comparison, the conventional X-ray diffraction method, which uses large amounts of samples, was also performed to determine the integral crystallinity of ancient silk. Thermal stability experiments by thermogravimetry(TG) as well as morphology observations by scanning electron microscopy(SEM) and optical microscopy(OM) all confirmed the deterioration of ancient silk. Moreover, the ageing mechanism of ancient silk was proposed with the assistance of an artificial ageing study. The results confirmed the effectiveness of SR-XRD as an ageing indicator, revealing the crystallinity distribution. This research could provide motivation to determine the deterioration status of ancient silk, and would also aid in explaining the fragility of ancient silk due to ageing.

• Progress in Medical Physics
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• v.22 no.3
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• pp.117-123
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• 2011

Synchrotron radiation (SR) imaging enables us to observe internal structures of biologic samples without staining. In this study, we obtained X-ray microscopic images of human breast tissues with 11.1 KeV hard X-ray microscope of the Pohang light source and used zone plates and phase-contrast technique to get high resolution X-ray images. Hard X-ray microscopic images of fibrocystic change and breast cancer tissues with a spatial resolution of 60 nm were obtained and from these images, we could observe the micro-structures of human breast tissue. Also we analyzed and compared these images, which revealed distinct features of each condition. In conclusion, SR imaging with phase-contrast hard X-ray microscope for medical application, especially in breast disease can give some useful information for clinical research.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.283.2-283.2
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• 2013

The variation of chemical and interfacial state during the growth of Ta2O5 films on the Si substrate by atomic layer deposition (ALD) was investigated using in-situ synchrotron radiation photoemission spectroscopy. A newly synthesized liquid precursor Ta(NtBu)(dmamp)2Me was used as the metal precursor, with Ar as a purging gas and H2O as the oxidant source. The core-level spectra of Si 2p, Ta 4f, and O 1s revealed that Ta suboxide and Si dioxide were formed at the initial stages of Ta2O5 growth. However, the Ta suboxide states almost disappeared as the ALD cycles progressed. Consequently, the Ta5+ state, which corresponds with the stoichiometric Ta2O5, only appeared after 4.0 cycles. Additionally, tantalum silicate was not detected at the interfacial states between Ta2O5 and Si. The measured valence band offset value between Ta2O5 and the Si substrate was 3.08 eV after 2.5 cycles.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.101-110
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• 2012

This paper is described the review of several selected accelerators and the use of accelerators in various purposes. The electrostatic accelerators and RF accelerators have been developed before the second world war for the purpose of basic research of physics mainly. RF driven accelerators have been achieved higher energy and applied in medical and industrial use after 1980's. Accelerators have improved incorporating new technologies : axial and horizontal injection, stripping extraction, superconducting RF, computer control, superconducting magnet etc.. Also recent key technologies as BT and NT make the expansion of applications of the accelerators.