Advanced Nanoscale Characterization of Cement Based Materials Using X-Ray Synchrotron Radiation: A Review

Sejung R. Chae,Juhyuk Moon,Seyoon Yoon,Sungchul Bae,Pierre Levitz,Robert Winarski,Paulo J. M. Monteiro 한국콘크리트학회 2013 International Journal of Concrete Structures and M Vol.7 No.2

We report various synchrotron radiation laboratory based techniques used to characterize cement based materials in nanometer scale. High resolution X-ray transmission imaging combined with a rotational axis allows for rendering of samples in three dimensions revealing volumetric details. Scanning transmission X-ray microscope combines high spatial resolution imaging with high spectral resolution of the incident beam to reveal X-ray absorption near edge structure variations in the material nanostructure. Microdiffraction scans the surface of a sample to map its high order reflection or crystallographic variations with a micron-sized incident beam. High pressure X-ray diffraction measures compressibility of pure phase materials. Unique results of studies using the above tools are discussed?a study of pores, connectivity, and morphology of a 2,000 year old concrete using nanotomography; detection of localized and varying silicate chain depolymerization in Al-substituted tobermorite, and quantification of monosulfate distribution in tricalcium aluminate hydration using scanning transmission X-ray microscopy; detection and mapping of hydration products in high volume fly ash paste using microdiffraction; and determination of mechanical properties of various AFm phases using high pressure X-ray diffraction.

High-resolution and High-contrast Bio-medical X-ray Imaging by Using Synchrotron Radiation in the PLS

J. Y. Huang,진경식,임재홍,H. Y. Kim,S. D. Jang,H. J. Choi,K. H. Gil,S. K. Lee 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.61

Since Roentgen’s discovery of X-ray, X-ray imaging technique has been the most important medical diagnosis tool for more than a century. Though there has been remarkable progress in X-ray imaging techniques, the contrast and the resolution of conventional X-ray imaging have been limited due to the weak absorption contrast of X-rays in bio-medical matter. However, as partially coherent synchrotron X-ray radiation and high-resolution detectors are now available, it is possible to get high-resolution phase-contrast X-ray images of bio-medical tissue in 3rd generation synchrotron light sources. In the Pohang Light Source (PLS), there are two X-ray microscopy beamlines operating for public users: the 1B2 beamline dedicated to high-resolution phase-contrast microscopy, and the 7B2 beamline for lensless white-beam micro-tomography. In this paper, we report phase-contrast X-ray imaging techniques and their applications in the PLS.

연 X-선 현미경을 이용한 금 나노입자 세포영상

권영만,김한경,김경우,김선희,윤홍화,천권수,강성훈,박성훈,정선관,윤권하 韓國電子顯微鏡學會 2008 Applied microscopy Vol.38 No.3

연 x-선 현미경은 ‘물의 창’ 영역(2.3~4.4 nm)의 파장을 이용하여, 수십 nm의 분해능으로 세포를 파괴하지 않고 살아있는 상태에서 세포의 내부구조를 관찰할 수 있어 가시광선현미경과 전자현미경을 단점을 보완하는 특징을 갖는 세포 생물학 연구에 적합한 현미경이다. 그러나 기존 연 x-선 현미경은 광원으로 방사선 가속기를 이용하기 때문에 사용이 제한적이었다. 이에, 본 연구에서는 2.88 nm의 연 x-선을 광원으로 사용하는 소형 연 x-선 현미경을 이용하여, 내포작용에 의해 금 나노입자를 포획한 HT1080과 MDA-MB 231 세포의 영상을 약 60 nm 분해능으로 획득하였다. 금 나노입자의 세포에 대한 독성을 제거하기 위하여 폴리에틸렌 글리콜을 캡핑하였고, 2.88 nm 파장의 연 x-선에 대하여 충분한 조영효과로 인하여 세포영상에서 뚜렷한 대조도를 나타내었다. 내포작용에 의해 액포에 포함되어 있는 다양한 크기의 금 나노입자 군집을 확인하였으며, 세포내부의 액포의 분포상태도 관찰할 수 있었다. 따라서 고분해능을 가진 소형 연 x-선 현미경을 이용하여 금 나노입자를 세포내의 미세기관이나 특정 단백질에 표지하면 연 x-선에 대한 조영효과의 증가에 의하여 더욱 유용한 정보를 획득할 수 있을 것으로 생각한다. A compact soft x-ray microscope operated in the ‘water window’ wavelength region (2.3~4.4 nm) was used for observing cells with nano-scale spatial resolution. To obtain cellular imaging captured with colloidal gold nanoparticles using a compact soft x-ray microscope. The colloidal gold nanoparticles showed higher contrast and lower transmission more than 7 times than that of cellular protein on the soft x-ray wavelength region. The structure and thickness of the cell membrane of the Coscinodiscus oculoides (diatome) and red blood cells were seen clearly. The gold nanoparticles within the HT1080 and MDA-MB 231 cells were seen clearly on the soft x-ray microscopy. The gold nanoparticles were aggregated within vesicles by endocytosis.

In vitro investigation of electrophoretically deposited bioactive hydroxyapatite/chitosan coatings reinforced by graphene

Đ,oš,ić,, Marija,Eraković,, Sanja,Janković,, Ana,Vukaš,inović,-Sekulić,, Maja,Matić,, Ivana Z.,Stojanović,, Jovica,Rhee, Kyong Yop,Miš,ković Elsevier 2017 Journal of industrial and engineering chemistry Vol.47 No.-

<P><B>Abstract</B></P> <P>Graphene (Gr) and natural polymer chitosan (CS) were introduced to hydroxyapatite (HAP) to produce a three-component composite coating, which was fabricated by cathodic electrophoretic deposition on Ti substrates in an ethanol suspension. These HAP/CS/Gr coatings were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements and found that the graphene into HAP/CS composites significantly improves their morphology, thermal stability, and bioactivity. Both HAP/CS and HAP/CS/Gr composite coatings are classified as non-cytotoxic when tested against healthy peripheral blood mononuclear cells (PBMC), while antibacterial activity against <I>Staphylococcus aureus</I> and <I>Escherichia coli</I> could not be verified.</P>

Al$_x$Ga$_{1-x}$N 박막의 조성이 분광학적 특성에 미치는 영향

김대중,김봉진,김덕현,이종원 한국물리학회 2018 New Physics: Sae Mulli Vol.68 No.12

본 연구에서는 Al$_x$Ga$_{1-x}$N 박막을 유기금속 화학증착법(metal organic chemical vapor deposition, MOCVD)을 이용하여 사파이어 (0001) 기판 위에 성장하였다. 성장된 박막의 결정구조를 조사하기 위하여 엑스선 회절 (X-ray diffraction, XRD) 패턴을 이용하였고, 박막의 표면 상태를 관찰하기 위하여 원자간력 현미경(atomic force microscopy, AFM)을 사용하였다. 또한 박막의 화학성분과 결합상태는 엑스선 광전자 분광분석기(X-­ray photoelectron spectroscopy, XPS)를 이용하여 분석하였다. 박막의 광학적 특성인 유사유전함수는 분광학적 타원편광분석법(spectroscopic ellipsometry, SE)을 사용하여 실온에서 2.0 $\sim$ 8.7 eV 포톤에너지 범위에서 측정되었다. 타원편광분석법으로 조사된 데이터들을 통해 얻은 유사유전함수 스펙트럼 <$\varepsilon(E)$> = <$\varepsilon_1(E)$> + $i$<$\varepsilon_2(E)$>에 나타난 $E_0$, $E_1$, 그리고 $E_2$와 같은 임계점 구조에 대하여 연구하였고, 각각의 임계점 피크들은 획득된 유사유전함수의 데이터를 이차 미분한 이계도함수 $d^2$<$\varepsilon(E)$>/$dE^2$를 이용하여 구하였다. 특히, $x$ = 0.18과 $x$ = 0.29 사이에 위치한 샘플($x$ = 0.18, 0.21, 0.25, 0.29)들은 Al의 조성이 증가함에 따라 임계점 피크들이 변화(blue-shift)한다는 것을 관측하였고, 이를 다른 문헌들과 비교 분석하였다. In this study, Al$_x$Ga$_{1-x}$N films were grown on (0001) sapphire substrates by using metal-organic chemical vapor deposition (MOCVD). The crystallinity of the grown films was examined with X-ray diffraction (XRD) patterns. The surfaces and the chemical properties of the Al$_x$Ga$_{1-x}$N films were investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The optical properties of the Al$_x$Ga$_{1-x}$N film were studied in a wide photon energy range between 2.0 $\sim$ 8.7 eV by using spectroscopic ellipsometry (SE) at room temperature. The data obtained by using SE were analyzed to find the critical points of the pseudodielectric function spectra, <$\varepsilon(E)$> = <$\varepsilon_1(E)$> + $i$<$\varepsilon_2(E)$>. In addition, the second derivative spectra, $d^2$<$\varepsilon(E)$>/$dE^2$, of the pseudodielectric function for the Al$_x$Ga$_{1-x}$N films were numerically calculated to determine the critical points (CPs), such as the $E_0$, $E_1$, and $E_2$ structure. For the four samples ($x$ = 0.18, 0.21, 0.25, 0.29) between a composition of $x$ = 0.18 and $x$ = 0.29, changes in the critical points (blue-shifts) with increasing Al composition at 300 K for the Al$_x$Ga$_{1-x}$N film were observed via ellipsometric measurements for the first time.

시화지구 연약점토의 광물학적 특성과 공학적 특성의 상관관계

김낙경,박종식,주용선,Kim Nak-Kyung,Park Jong-Sik,Joo Yong-Sun 한국지반공학회 2004 한국지반공학회논문집 Vol.20 No.9

국내 연약지반 활용을 위한 효율적이고 경제적인 안정처리 공법의 선정과 설계 및 시공을 위해서는 대상지반의 특성을 파악하는 것이 대단히 중요하다. 본 연구는 시화지구 연약점토의 물리적, 역학적 특성과 광물학적 특성을 파악하여 연약점토의 물리적, 역학적 특성과 광물학적 특성과의 상관관계를 알아보는 데 그 목적이 있다. 본 연구에서 는 연약점토의 광물학적 특성을 파악하기 위하여 X선 형광분석, X선 회절분석, 주사전자현미경분석과 에너지분산미분석 실험을 실시하였으며 시화지구 연약지반의 시추조사결과, 실내시험 및 현장시험결과와의 상관관계를 알아보았다. 또한 시화지구 연약점토의 특성을 양산과 군산 지역 연약점토의 특성과 비교하였다. The characteristics of soft clays are very important for the land development plan. This study is to investigate correlations between the engineering properties and the characteristics of clay minerals of the undisturbed clay samples obtained from Sihwa area. This study included X-Ray diffraction analysis, X-Ray fluorescence spectrometer analysis, scanning electron microscopy analysis and energy dispersive X-Ray spectrometer analysis. The correlations between the clay mineral properties and the laboratory and field testing results were investigated. The characteristics of soft clay in Sihwa area were compared with those in Yangsan and Kunsan area.

X-ray imaging of various biological samples using a phase-contrast hard X-ray microscope

Kim, Guk Bae,Yoon, Yae Jin,Shin, Tae Joo,Youn, Hwa Shik,Gho, Yong Song,Lee, Sang Joon Wiley Subscription Services, Inc., A Wiley Company 2008 Microscopy research and technique Vol.71 No.9

<P>In this study, we visualized the internal structures of various bio-samples and found the optimum conditions of test samples for the 7 keV hard X-ray microscope of the Pohang light source. From the captured X-ray images, we could observe the intercellular and intracellular structures of dehydrated human cells and mouse tumor tissues without using any staining materials in a spatial resolution better than 100 nm. The metastasized lung tissue, which was several tens of micrometers in thickness, was found to be very well suited to this hard X-ray microscope system, because it is nearly impossible to observe such a nontransparent and thick sample with a high spatial resolution better than 100 nm using any microscopes such as a soft X-ray microscope, an optical microscope, or an electron microscope. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc.</P>

Synchrotron-based Transmission X-ray Microscopy (TXM) Observations of Fully Hydrated Blood Platelets and Their Activation Process

양누리,Hyun Woo Nho,Yogesh Kalegowda,Jin Bae Kim,송재우,신현준,윤태현 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

Platelets are anuclear discoid-shaped blood cells with key roles in human body. To understand the mechanisms of their activation process, it is required to have analytical imaging techniques capable of acquiring platelet images under fully hydrated conditions. Herein, for the first time, we demonstrate the capability of synchrotronbased transmission X-ray microscopy (TXM) to study platelets (resting and ADP activated) under hydrated and air-dried conditions. To confirm the biological imaging capability of TXM, fixed platelets were imaged and compared with whole mount electron microscopy (EM) images. TXM provided morphological information with sufficient spatial resolution with simple and quick sample preparation procedure. We also observed temporal changes during the platelet activation, which initially had a discoid shape (0 s), formed pseudopodia (30 s) and generated a network of fibrin (5 min). Our results clearly demonstrate the potential of TXM technique to study fully hydrated biological samples under in situ conditions.

Synchrotron-based Transmission X-ray Microscopy (TXM) Observations of Fully Hydrated Blood Platelets and Their Activation Process

Yang, Nuri,Nho, Hyun Woo,Kalegowda, Yogesh,Kim, Jin Bae,Song, Jaewoo,Shin, Hyun-Joon,Yoon, Tae Hyun Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

Platelets are anuclear discoid-shaped blood cells with key roles in human body. To understand the mechanisms of their activation process, it is required to have analytical imaging techniques capable of acquiring platelet images under fully hydrated conditions. Herein, for the first time, we demonstrate the capability of synchrotron-based transmission X-ray microscopy (TXM) to study platelets (resting and ADP activated) under hydrated and air-dried conditions. To confirm the biological imaging capability of TXM, fixed platelets were imaged and compared with whole mount electron microscopy (EM) images. TXM provided morphological information with sufficient spatial resolution with simple and quick sample preparation procedure. We also observed temporal changes during the platelet activation, which initially had a discoid shape (0 s), formed pseudopodia (30 s) and generated a network of fibrin (5 min). Our results clearly demonstrate the potential of TXM technique to study fully hydrated biological samples under in situ conditions.

A New Method for Investigation of the Hair Shaft: Hard X-Ray Microscopy with a 90-nm Spatial Resolution

전수영,구자웅,홍승필,오탁헌,윤화식,이원수 연세대학교의과대학 2008 Yonsei medical journal Vol.49 No.2

Various methods have been used to investigate the hair shaft. In the ultrastructural hair field, scanning and transmission electron microscopies are widely used investigative methods, but they have some technical limitations. Recently, X-ray microscopes with sub-micron spatial resolution have emerged as useful instruments because they offer a unique opportunity to observe the interior of an undamaged sample in greater detail. In this report, we examined damaged hair shaft tips using hard X-ray microscopy with a 90 nm spatial resolution. The results of this study suggest that hard X-ray microscopy is an alternative investigative method for hair morphology studies.