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Lasing action by planar-, fiber-, or ring-type waveguide has been extensively investigated with different types of microcavities such as thin films, wires, cylindrical tubes, or ribbons. However, the lasing action by sharp bending waveguide, which promises efficient interconnection of amplified light in the photonic circuits, remains unexplored. Here, we report the first observation of microcavity effects in the organic rectangular microtubes (RMTs) with sharp bends (ca. 90°) and subwavelength nanoscale wall thicknesses, based on single crystalline and themostable tetra(4-pyridyl)porphyrin (H(2)TPyP)-RMTs synthesized by the VCR process. A bright tip emission is observed from the sharp bending edges of a single RMT upon laser excitation, demonstrating a clear waveguiding behavior in RMT. The appearance of a peak from the (0-1) band at a threshold tube length and the gradual decrease of its full width at half-maximum (fwhm) suggest that amplification of spontaneous emission (ASE) is developed by stimulated emission along the walls of the RMTs. The ehancement of the ASE peak together with the narrowing of its fhwm over a threshold pump power and the tube size (width and length) dependence of the mode spacing strongly support vibronic lasing action in the RMTs. The stimulated emission by the subwavelength bending waveguide demonstrates that the organic RMTs can be applied as new building blocks for micromanipulation of optical path and amplification in the integrated circuits for efficient photonic devices.

Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm3 with accuracy better than 1 × 10−3 mm3. This level of performance is currently suitable for animal studies, while further developments are required for clinical application. Refereed/Peer-reviewed

The effects of strain energy on the preferred orientation of TiN thin films were investigated. In the TiN film deposited by plasma‐enhanced chemical‐vapor deposition with a power of 50 W, the overall energy of the film mainly depended on the surface energy because its strain energy was relatively small. The preferred orientation of the film corresponded to the plane with the lowest surface energy, i.e., (200). However, in the TiN film deposited by rf sputtering with a power of 200 W, the overall energy of the film was largely controlled by strain energy due to its large strain energy, and its growth orientation corresponded to the plane with the lowest strain energy, i.e., (111). Furthermore, the preferred orientation of the TiN film was changed from (200) to (111) with the film thickness. It is considered that this phenomenon is due to the increase of strain energy with its thickness.

We investigated the structural behavior of the Ni/Au contact on GaN(0001) and found the catalytic role of Au during annealing, using in situ x-ray scattering. The oxidation kinetics of Ni during annealing in air was greatly affected by the presence of Au. The accelerated GaN decomposition and Ni nitride formation during annealing in N2 also provide evidence of the catalytic role of Au. The results suggest that oxidized Ni/Au ohmic contact exhibit better thermal stability than that of the N2 annealed Ni/Au contacts.

We reveal the existence of interfacial, epitaxial, Pd grains in an as-deposited Pd film evaporated on GaN (0001) at room temperature. The origin of the Pd epitaxy was attributed to 6/7 matched interface structure. The Pd film was completely transformed to Ga 2 Pd 5 and Ga 5 Pd gallides in epitaxial relationships with GaN at an annealing temperature of 700°C.

The microstructure in GaN nucleation layers was studied in synchrotron X-ray scattering and transmission electron microscopy experiments. We revealed the existence of tensile-strained interfacial domains, which was originated from 6/7 matched interface structure.

When a coffee drop dries on a solid surface, it leaves a ringlike deposit along the edge and this is known as the "coffee-ring effect." We find a different motion of particles repelling the coffee-ring effect in drying droplets; the motion of particles that is initially toward the edge by the coffee-ring effect is reversed toward the center by a capillary force. The reversal takes place when the capillary force prevails over the outward coffee-ring flow. We discuss the geometric constraints for the capillary force and the reverse motion. Our findings of reversal phenomena would be important in many scenarios of drying colloidal fluids.

Synchrotron X-ray bioimaging was successfully carried out to observe bone regeneration by a novel artificial bone substitute of bioactive MegaGen Synthetic Bone (MGSB) and hyaluronate (HA) hydrogels. A biphasic calcium phosphate of MGSB was prepared by chemical precipitation method, with a porous spherical morphology. On the basis of the fact that HA plays important roles in bone regeneration and promotes the differentiation, vascularization, and migration of stem cells, HA-cystamine (CYS) hydrogels with cleavable disulfide linkages were prepared to supply HA continuously for effective bone regeneration by their controlled degradation in vivo. Among seven different samples using Bio-OSS®, MGSB, and/or several kinds of HA hydrogels, MGSB/HA-CYS hydrogels resulted in the most significant bone regeneration in the calvarial critical bone defect of New Zealand white rabbits. Histological and histomorphometric analyses revealed that the bone regeneration by MGSB/HA-CYS hydrogels was as high as 43%, occupying 71% of the bone defect area with MGSB in the form of a calvarial bone plate in 4 weeks. After that, MGSB was bioabsorbed and replaced gradually with regenerated bones as observed in 8 weeks. Synchrotron X-ray imaging clearly confirmed the effective bone regeneration by MGSB/HA-CYS hydrogels, showing three-dimensional micron-scale morphologies of regenerated bones interconnected with MGSB. In addition, sequential nondestructive synchrotron X-ray tomographic analysis results from anterior to posterior of the samples were well matched with the histomorphometric analysis results. The clinically feasible artificial bone substitutes of MGSB/HA-CYS hydrogels will be investigated further for various bone tissue engineering applications using the synchrotron X-ray bioimaging systems.

In order to understand the formation mechanism of the superconducting phases, amorphous BiSrCaCuO films prepared by RF magnetron sputtering were rapidly cooled after various annealing processes. The 2201 phase began to grow at 600°C and the 2212 phase with c -axis orientation was grown up to 870°C. Two kinds of needle-like secondary phases which were rich in Ca and Cu were also observed from 870°C, along with a partial melting in the matrix. After holding at 880°C and 890°C for 6 h, the matrix was mostly liquefied and transformed to the 2201 phase after rapid cooling. However, when slowly cooled at 1°C/min, the 2212 phase with the c -axis orientation was obtained. On the other hand, when slowly cooled after holding at 870°C for 6 h, the remaining 2212 phase and the co-existing liquid phase within the matrix could also produce the 2223 phase.

Diamond films were deposited on (1 0 0) silicon wafer by microwave plasma-enhanced chemical vapour deposition. The microstructural changes of the diamond films were studied in relation to the pre-treatment of the silicon substrate, the methane concentration and the substrate temperature. The ultrasonic method for the pre-treatment of the silicon substrate increased the nucleation density, resulting in the deposition of small diamond particles. The surface morphology changed from the close-packed (1 1 1) to the (1 0 0) plane with increase in the methane concentration due to the decreased adatom mobility. The morphology also changed from (1 1 1) to (1 0 0) planes with substrate temperature, due to the effect of the increased chemical species. The change in the crystallinity with deposition time was also investigated.

The structural evolution during heteroepitaxial growth of ZnO/sapphire(001) by radio-frequency magnetron sputtering has been studied using real-time synchrotron x-ray scattering. The two-dimensional (2D) ZnO(002) layers grown in the initial stage are highly strained and well aligned to the substrate having a mosaic distribution of 0.01° full width at half maximum (FWHM), in sharp contrast to the reported transition 2D layers grown by molecular-beam epitaxy. With increasing film thickness, the lattice strain is relieved and the poorly aligned (1.25° FWHM) three-dimensional (3D) islands are nucleated on the 2D layers. We attribute the 2D–3D transition to the release of the strain energy stored in the film due to the film/substrate lattice mismatch.

We report the observation of a strong second-order nonlinear optical response from epitaxial Ba0.48Sr0.52TiO3 thin films grown on MgO(001) by magnetron sputtering. The result is unexpected since the crystal structure of Ba0.48Sr0.52TiO3 is centrosymmetric under ambient conditions. A second-order nonlinear susceptibility d33 as large as 11 pm/V at a fundamental wavelength of 1.064 μm is observed in a 300 A thick film. By studying a series of films with different strains, induced by a film–substrate lattice mismatch, we conclude that the resulting tetragonal distortion, presumably accompanied by a loss of inversion symmetry, is responsible for the second-harmonic generation.

The formation of crystalline Ba-ferrite/sapphire(001) films in an amorphous precursor during annealing was studied in a real-time synchrotron x-ray scattering experiment. From the x-ray integrated intensity and the surface morphology, we found that the crystalline Ba-ferrite phase was formed by solid phase transformation of the intermediate crystalline α-Fe2O3 phase, not by direct crystallization of the amorphous precursor. The solid phase transformation occurred at temperature above 500 °C. The high crystallization temperature of the Ba-ferrite phase was attributed to the activation barrier for the diffusion of Ba ions into the α-Fe2O3 phase.

Poly(dimethylsiloxane) [PDMS] is the most widely used siliconbased organic polymer due to its excellent mechanical, chemical, and optical properties for microfluidics, microchips, microlithography, electrophoresis, and biomedical applications. One challenge for the applications is to modify the surface wettability with long-term stability in air. Herein we present a highly efficient protocol for the surface modification of PDMS using Xray irradiation, which enables not only to “ablate” hydrophobic molecules from PDMS, rendering the surface hydrophilic in atmosphere and room temperature conditions, but also to “deposit” them on flat and nanostructure surfaces, inducing hydrophobic surfaces. In spite of the development of many interesting applications, microfluidic devices based on PDMS are not yet standard equipment observed in most biologists’ toolboxes. One of the obstacles is the difficulty in making PDMS-based devices. For instance, soft lithography, the main fabrication process, requires using a clean room, which makes the traditional soft lithography approach painfully slow and difficult. The intrinsic hydrophobicity of PDMS that comes from Si CH3 end-bonds is another big problem in applying as an ideal flexible substrate for microfluidic channels. 4] The PDMS surface can be rendered hydrophilic using a variety of methods (see a review) such as oxygen plasmas, corona discharges, and ultraviolet lights, and exposures of lasers or excimer lamps. The hydrophilic property, however, quickly diminishes through the sequent hydrophobic recovery. 4] Such physical protocols usually require an additional sophisticated chemical process to stabilize the hydrophilic SiO2 layer. [4] Laser irradiation that enables one not only to modify, but also to ablate the PDMS surface through photothermal and photochemical effects may have a limitation in applications to organic polymers such as PDMS because of thermal damage. It is thus required to develop a versatile and robust protocol to modify and ablate polymers simultaneously with a finely tunable, nonthermal irradiation technique. Contrary to laser beams, ionizing radiation can induce photochemical scission of PDMS without thermal damage. For instance, electron irradiation, revealed by Miller as early as 1960, causes Si CH3 and SiCH2 H scissions, generating H2, CH4, and C2H6 as gaseous products. [10,11] Despite the well-established radiation chemistry of PDMS, there are few reports to demonstrate highly efficient wettability changes in PDMS using ionizing radiation. From studies on various soft matter and inorganic systems using hard X-rays (10–60 keV), we recently developed an X-ray ablation technique using rapid depolymerization of organic polymers. Here our results of PDMS demonstrate that X-ray irradiation is a highly efficient and feasible protocol for surface modification through PDMS ablation. The X-ray-induced ablation enables one not only to oxidize the PDMS surface (hydrophilicity) but also to deposit the ablated PDMS (hydrophobicity) on other hydrophilic surfaces. The evidence of the X-ray-induced PDMS ablation and deposition is shown using contact-angle and attenuated total reflection (ATR) FT–IR measurements, which are typically used to prove the mechanism. We suppose that the X-ray-induced ablation–deposition process occurs as illustrated in Scheme 1. A rapid chain scission initially occurs in the irradiated PDMS substrate under hard X-ray irradiation. Once the chain scission at the Si CH3 (or SiCH2 H) bonds occurs, the irradiated surface can easily be oxidized, as commonly observed in laser ablation, and

Synchrotron phase-contrast hard X-ray imaging is used to provide highly efficient direct visualization of landslide dynamics and granular flows in fully wet granular piles. High penetration capability and phase-contrast enhancement of hard X-rays offer marked advantages in the precise tracking of individual granular movements through a thick water medium. It is revealed that the stress accumulation follows a power-law evolution while the relaxation follows an exponential one. The onset of landslide emerges at the trade-off of the two evolutions.

Recent discoveries show steady improvements in life expectancy during modern decades. Does this support that humans continue to live longer in future? We recently put forward the maximum survival tendency, as found in survival curves of industrialized countries, which is described by extended Weibull model with age-dependent stretched exponent. The maximum survival tendency suggests that human survival dynamics may possess its intrinsic limit, beyond which survival is inevitably forbidden. Based on such tendency, we develop the model and explore the patterns in the maximum lifespan limits from industrialized countries during recent three decades. This analysis strategy is simple and useful to interpret the complicated human survival dynamics., 11 pages, 3 figures, 2 tables; Natural Science (in press)

Conventional x-ray diffraction failed to provide correct information on alloying of materials made of elements with close lattice parameters, even for elements commonly accepted to have miscibility. Using anomalous x-ray scattering, we showed that nanostructured NiCo films did not necessarily form solid solution as expected from their phase diagram or suggested by the results of conventional x-ray diffraction.

We show that a photoelectron spectromicroscope of the photoelectron emission microscope type can be used as an x-ray imaging detector for radiology. Using high penetration hard-x-ray photons (wavelength < 0.1 nm), samples as thick as a few millimeters can be imaged with submicron resolution. The high imaging resolution enables us to substantially decrease the object-detector distance needed to observe coherent based contrast enhancement with respect to the standard film-based detection technique. Our result implies several advantages, the most important being a marked reduction of the required source emittance for contrast enhanced radiology. (C) 1999 American Institute of Physics. [S0003-6951(99)00842-6].

The effects of growth temperature on the microscopic structure of GaN nucleation layers were studied in a synchrotron x-ray scattering experiment. As the growth temperature increases from 467 to 655 °C, the stacking of GaN changes from random stacking to a mixture of cubic and hexagonal stacking. With increasing the growth temperature, the order in the atomic layer positions in the out-of-plane direction increases and the mosaic distribution becomes narrow. The optimal photoluminescence spectrum was obtained on the GaN epilayer deposited on the nucleation layer grown at 505 °C.

The crystallization of the amorphous precursor of a Ba-ferrite thin film was studied in real-time synchrotron x-ray scattering experiments. We found that a very thin (/spl sim/50 /spl Aring/) epitaxial Fe/sub 3/O/sub 4/ sublayer was formed in the as-deposited amorphous precursor grown on sapphire [001]. The nucleation of crystalline /spl alpha/-Fe/sub 2/O/sub 3/ phase from the amorphous precursor started at 300/spl deg/C and continued at higher annealing temperatures. The mosaic distribution of the /spl alpha/-Fe/sub 2/O/sub 3/ grains was about 0.67/spl deg/ full-width at half-maximum (FWHM), relatively large compared to that of the Fe/sub 3/O/sub 4/ sublayer. The crystalization of the Ba-ferrite phase occurred at 600/spl deg/C. The Fe/sub 3/O/sub 4/ sublayer was transformed from 600/spl deg/C to extremely well-aligned (0.05/spl deg/ FWHM) /spl alpha/-Fe/sub 2/O/sub 3/ phase. It is noteworthy that the crystallization of the Ba-ferrite phase occurred duping the transformation of the Fe/sub 3/O/sub 4/ sublayer to the well-aligned /spl alpha/-F/sub 2/O/sub 3/ grains. The Fe/sub 3/O/sub 4/ sublayer might play an important role in the crystallization of amorphous Ba-ferrite film.

We discovered that intense irradiation by hard-x-ray strongly decreases the effects of natural surface tension of water in droplets and capillary tubes. The effect was revealed by direct experimental observations with phase contrast microradiology. A model based on ionization and surface charging explains this so far undetected phenomenon. The effect can impact the results of many experimental techniques based on x rays. This is an example of the largely unexplored effects that can be produced by extreme intense x-ray irradiation-an important issue due to current development of x-ray free-electron-lasers with unprecedented brilliance.

In biomedical application study using phase contrast X-ray, both sample thickness or density and absorption difference are very important factors in aspects of contrast enhancement. We present experimental evidence that synchrotron hard X-ray are suitable for radiological imaging of biological samples down to the cellular level. We investigated the potential of refractive index radiology using un-monochromatized synchrotron hard X-rays for the imaging of cell and tissue in various diseases. Material had been adopted various medical field, such as apoE knockout mouse in cardiologic field, specimen from renal and prostatic carcinoma patient in urology, basal cell epithelioma in dermatology, brain tissue from autosy sample of pakinson's disease, artificially induced artilrtis tissue from rabbits and extracted tooth from patients of crack tooth syndrome. Formalin and paraffin fixed tissue blocks were cut in 3 mm thickness for the X-ray radiographic imaging. From adjacent areas, 4 μm thickness sections were also prepared for hematoxylin-eosin staining. Radiographic images of dissected tissues were obtained using the hard X-rays from the 7B2 beamline of the Pohang Light Source (PLS). The technique used for the study was the phase contrast images were compared with the optical microscopic images of corresponding histological slides. Radiographic images of various diseased tissues showed clear histological details of organelles in normal tissues. Most of cancerous lesions were well differentiated from adjacent normal tissues and detailed histological features of each tumor were clearly identified. Also normal microstructures were identifiable by the phase contrast imaging. Tissue in cancer or other disease showed clearly different findings from those of surrounding normal tissue. For the first time we successfully demonstrated that synchrotron hard X-rays can be used for radiological imaging of relatively thick tissue samples with great histological details.

Background/aims: There is a need for development of non-invasive methods to improve early diagnosis and screening of suspected malignant lesions. Phase-contrast X-ray microscopy (PCXM) has potential to reveal the structures inside soft tissues, and fine details can be observed without any staining or contrast-enhancing cell preparation. We aimed to investigate the possibility that PCXM can be used to explore the microscopic details of basal cell carcinoma (BCC). Methods: Paraffin blocks of specimens from patients with basal cell carcinoma were cut with 30 μm thickness for PCXM imaging. Experiments were performed at the International Consortium of Phase Contrast Imaging and Radiology (ICPCIR) (7B2) beamline of the Pohang light source in Korea. The PCXM images were achieved by using coherent hard X-rays from a synchrotron source with no monochromatization. Results: We could obtain images with clear edge enhancement by PCXM. The images taken with this technique showed clear anatomic details of organelles in normal skin such as epidermis, dermis and skin appendages. Most of cancerous lesions were clearly differentiated from adjacent normal tissues and the images closely corresponded to those obtained with low-magnification optical microscopy. Conclusion: In this pilot study, we successfully demonstrated that synchrotron PCXM could be used for radiological imaging of BCC with great anatomic details.

Keywords: CIBM-PC Reference EPFL-ARTICLE-186229doi:10.1103/PhysRevB.76.064117 Record created on 2013-04-25, modified on 2017-05-12

In the present study the feasibility of applying synchrotron radiation to the morphological study of early-stage lung cancer has been investigated. Lewis lung cancer was implanted and grown in a nude mouse for different periods, and imaged using phase-contrast synchrotron X-rays. Morphological differences were clearly shown between the normal lung and cancerous tissues at this early stage. Irregular and tortuous angiogenesis were found in the periphery region of the developing lung cancer. Results from this study indicate that synchrotron X-rays can be used for imaging cancer development and progression with minimal invasion. (C) 2008 International Union of Crystallography.

The correlation between the microscopic lattice plane curvature and the dislocation structure in thermal warpage of 200 mm-diameter Czochralski Si (001) wafers has been investigated using high-resolution X-ray diffractometry and topography. It is found that the (004) lattice plane curvature is locally confined between two neighboring slip bands, with the rotation axis parallel to the slip bands. High-resolution topography reveals that the curvature resulted from a fragmented dislocation structure. The local confinement is attributed to the multiplication of the dislocations that are generated between the two slip bands.

Novel threadlike structures, so-called Bonghan threads, inside large caliber lymphatic vessels were recently observed by using the Janus Green B staining in the case of rabbits, and by using fluorescent magnetic nanoparticles for rats. They are thought to have channels through which some liquid with abundant hyaluronic acid (HA) flows. In the present work, the authors put forward a hypothesis to test that the Bonghan threads can be visualized in vivo by HA-staining dye, Alcian blue, and that the channels may be revealed by using X-ray microtomography.Alcain blue was injected into a lymph vessel near the caudal vena cava of a rat to make the Bonghan threads visible. Specimens were stained with YoYo-1 and Masson's trichrome. They were also examined by confocal microscopy and X-ray microtomography. A Bonghan thread was well stained by Alcian blue and was about 50 microm thick and 10-20 times thinner than the surrounding lymphatic vessel. It had a broken line shape, with a distribution of rod-shaped nuclei, which is the characteristic of Bonghan threads in general. Whereas lymphatic vessels are surrounded by a collagenous matrix, Bonghan threads do not contain any collagenous component. X-ray microtomography revealed continuous microchannels inside the Bonghan threads.Bonghan threads contain HA abundantly, harbor continuous microchannels, and have characteristic distribution of the rod-shape nuclei. Thus, they are novel anatomical structures with liquid-carrying microchannels.

Having better edge enhancement and penetrating power, refractive index radiology is suitable for the imaging of weakly absorbing objects such as tissue specimens. In this study the potential of refractive index radiology was evaluated for the imaging of renal cell carcinoma (RCC) and prostate cancer (PCA).Specimens were cut in 3 mm and 4 microm thickness for X-ray radiology and hematoxylin and eosin (HE) staining, respectively. Radiographic images of RCC and PCA were obtained using the synchrotron hard X-rays from the 7B2 beam-line of the Pohang Light Source (PLS). The imaging technique applied was phase-contrast radiology based on the refraction enhancement mechanism. The resulting radiographic images were analyzed in correlation with those of optical microscopy.Using unmonochromatized hard X-rays, it was possible to obtain images with clear edge enhancement and relatively large field of view (6 cm x 6 cm). Even with overlapping signals from thick samples (more than 700-fold thicker than microscopic images), radiographic images clearly showed histological information of organelles in normal kidney such as glomeruli, tubules, and collecting ducts. Histological information of RCC including tumor subtypes and minute changes such as cystic degeneration could be identified without difficulty. The radiographic images of the prostate were comparable with those of low magnification optical microscopy, providing good visualization of normal microstructures such as adenoma, smooth muscle, and normal glands, or differentiation of tiny tumors from surrounding normal tissues.These results suggest the potential of refractive index radiology to provide a new way of imaging biological tissues with low absorption contrast such as RCC and PCA.

We used an approach combining Inductively Coupled Plasma (ICP) etching process and high resolution electron beam lithography and successfully fabricate high aspect ratio zone plate for hard‐x‐ray applications. The electron beam lithography defines the pattern with outmost zone dimension smaller than 100nm while the consequently ICP produced high aspect ratio structures. Both chacteristics, high resolution patterning and high aspect ratio are required to produce zone plate devices for multi‐keV x‐rays. We demonstrated that a zone plate with a 60nm outmost zone and a thickness of 500nm is achievable by this approach.

A facile radiation method was developed to obtain micro‐sized poly (methyl methacrylate) (PMMA) particles and create patterned coating on different substrates by a synchrotron x‐ray induced dispersion polymerization. The polymerization of MMA monomer and well defined patterning was successfully realized. The produced PMMA particles and patterning were characterized by Fourier transformation infrared (FTIR), 1H‐Nuclear Magnetic Resonance (NMR), and Scanning Electron Microscope (SEM). The observed patterning contrast essentially derived from a variation of size, density and morphology of particles and the type of substrate materials used.

Synchrotron X‐ray micro‐imaging method has been used to observe internal structures of various organisms, industrial devices, and so on. However, it is not suitable to see internal flows inside a structure because tracers typically employed in conventional optical flow visualization methods cannot be detectable with the X‐ray micro‐imaging method. On the other hand, a PIV (particle image velocimetry) method which has recently been accepted as a reliable quantitative flow visualization technique can extract lots of flow information by applying digital image processing techniques However, it is not applicable to opaque fluids such as blood. In this study, we combined the PIV method and the synchrotron X‐ray micro‐imaging technique to compose a new X‐ray PIV technique. Using the X‐ray PIV technique, we investigated the optical characteristics of blood for a coherent synchrotron X‐ray beam and quantitatively visualized real blood flows inside an opaque tube without any contrast media. The velocity field infor...

X‐ray phase tomography and phase imaging are promising ways of investigation on low Z material. A polymer blend of PE/PS sample was used to test the 3D phase retrieval method in the parallel beam illuminated microscope. Because the polymer sample is thick, the phase retardation is quite mixed and the image can not be distinguished when the 2D transport intensity equation (TIE) is applied. In this study, we have provided a different approach for solving the phase in three dimensions for thick sample. Our method involves integration of 3D TIE/Fourier slice theorem for solving thick phase sample. In our experiment, eight sets of de‐focal series image data sets were recorded covering the angular range of 0 to 180 degree. Only three set of image cubes were used in 3D TIE equation for solving the phase tomography. The phase contrast of the polymer blend in 3D is obviously enhanced, and the two different groups of polymer blend can be distinguished in the phase tomography.

A high‐resolution zone plate for focusing and magnifying hard‐x‐rays require very high fabrication precision and high aspect ratio metal structures and therefore post perhaps the most challenging task to the nanofabrication. We present a nanofabrication strategy to fabricate such devices for x‐ray applications which takes advantage of the state‐of‐the‐art x‐ray lithography and electroplating processes. The substrate used to fabricate the x‐ray mask is first prepared by depositing Si3N4 film on a Si wafer. Electron beam lithography capable of writing small lines (

We report a technique for detection of sub‐cellular organelles and proteins with hard x‐ray microscopy. Several metals were used for enhancing contrast for x‐ray microscopy. Osmium tetroxide provides an excellent stain for lipid and can delineate cell membrane. Uranyl acetate has high affinity for nucleotide and can stain nucleus. Immunolocalization of specific proteins and sub‐cellular organelles was achieved by 3’3 diaminobenzidine (DAB) with nickel enhancement and nanogold‐conjugated secondary antibody with silver enhancement. The x‐rays emitted from synchrotron source was monochromatized by double crystal monochromator, the photon energy was fixed at 8 keV to optimize the focusing efficiency of the zone plates. The estimated resolution is about 60 nm. When compared with visible light and conventional confocal microscopy, the X‐ray microscopy provides a superior resolution to both conventional optical microscopes.

The crystallization of amorphous BaxSr1−xTiO3 (BST) thin films was studied in a synchrotron x-ray scattering experiment. In a 550 A thick film, the crystallization to perovskite phase was occurred at around 700 °C, while a 5500 A thick film became crystalline at 500 °C. The thickness dependence of the crystallization was attributed to the observed intermediate phase nucleated near 600 °C at the interface. In thin films, high annealing temperature was required due to the energy barrier between the perovskite phase and the intermediate phase. In the thick film, the perovskite phase was nucleated directly from the amorphous phase in the bulk of the film concurrent to the nucleation of the intermediate phase at the interface.

The origin of threading dislocations (TDs) in GaN epitaxial layers grown on sapphire (0001) substrate is investigated using moire fringes from plan-view transmission electron microscopy. The studied samples are nucleation layers deposited at 540°C for times ranging from 20s to 180s. This initial stage growth gives rise to islands which are randomly rotated and relaxed with misfit dislocations. The islands that start to coalesce from 60s growth time keep this random orientation and this leads to the bending of 60° misfit dislocations in the interface plane to form a-type TDs inside low angle boundaries.

Parkinson's disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons and the presence of Lewy bodies in neurons. Morphological study of Lewy bodies is important to identify the causes and the processes of PD. Here, we investigate a possibility of phase contrast radiography using coherent synchrotron X-rays to explore the microscopic details of Lewy bodies in thick (approximately 3 mm) midbrain tissues. Autopsied midbrain tissues of a PD patient were sliced in 3 mm thickness and then examined using synchrotron X-rays from the 7B2 beamline of the Pohang Light Source. Refraction-enhanced phase contrast radiography and microtomography were adopted to identify dark core and dim edge of Lewy bodies in neurons. The morphology of Lewy bodies was clearly revealed by the phase contrast radiography in very thick (3 mm) midbrain tissues without any staining treatment. Three-dimensional volume rendered microtomography of the autopsied midbrain tissues demonstrates striking evidence that several Lewy bodies are agglomerated by dim edges in a neuron. We suggest that the phase contrast radiography could be a useful tool to morphologically investigate the causes or the processes in PD.

To examine the pathophysiology of atherosclerosis, imaging the vascular wall and pathology without tissue damage is required. We used the unmonochromatized synchrotron X-ray to acquire in vivo real-time and ex vivo images of atherosclerotic lesions in apo E-knockout mice without contrast agents or staining.In the five apo E-knockout mice (apo E-/-, 12, 24, 32, 48, 62-week-old, 3 males) and age/sex matched five wild type mice on cow diets, we acquired in vivo real-time images of thoracic aorta without contrast agents and then, the central arterial trees were dissected intact. Ex vivo synchrotron images with tomographic reconstruction were done and compared with the corresponding pathology.For all living animals, in vivo real-time images of thoracic aorta could be acquired without contrast agents but could not identify the atherosclerotic lesions. Ex vivo images accurately determined aortic wall and atherosclerotic plaque without staining in comparison to histopathology according to the AHA classification (r=0.84, p0.001). The volume rendered 3 D images of plaque showed central cholesterol clefts as matched with optical images.The combination of synchrotron enhanced X-ray microscopy and genetically engineered hyperlipidemic animals would be a useful tool to investigate the changes of advanced atherosclerotic lesions.

In order to investigate FeSO4, ZnSO4 (the two of main metal compositions of Shanghai PM2.5 (particle matter with those aerodynamical diameter

We give an overview of experimental investigations and theoretical modeling of elastic interaction and transformations of dislocated micropipes in growing crystals. We consider elastic interaction of pair of micropipes, split of a micropipe into smaller dislocated micropipes and/or full-core screw dislocations, elastic interaction of micropipe steps, micropipe grouping and twisting. The models reviewed explain the experimental observations of ramified, twisted and grouped micropipes in silicon carbide.

We investigated degradation behavior of oxide cathodes in CRTs. The excess (or free) Ba enrichment process on the surface of oxide cathode, which starts to be induced from activation process, is a complex phenomenon which includes electrolytic transport, chemical reduction, and boundary diffusion, etc. We reveal that degradation behavior of oxide cathodes, which is directly related with the free Ba enrichment process, is able to be described by the stretched exponential model that has been successfully used to describe the complex dynamics of various systems. We derive a simple longevity equation, which depends on two parameters of stretched exponential model: i) characteristic life and ii) stretched exponent. We demonstrate that degradation factors, for example, temperature, can significantly affect the two parameters and in turn longevity. It is interesting that oxide cathodes, which have been applied as electron sources for /spl sim/100 years, can be described as dynamics of complex systems in modern physics.

With the aim of checking the validity of methods for characterizing the adhesion between inorganic materials with high surface energies, the properties of the adhesion between an inorganic material (indium tin oxide (ITO)) and model surfaces with various surface energies (Cl-, NH2-, CH(3)-, and CF3-functionalized surfaces) were evaluated using atomic force microscopy (AFM) and the Johnson-Kendall-Roberts (JKR) apparatus. For this purpose, the AFM tip and the JKR lens were modified with ITO using radio frequency (rf) magnetron sputtering. The work of adhesion between the ITO coating and each model surface was estimated using AFM and the JKR apparatus and compared with the result obtained from contact angle measurements. The adhesion forces determined from the force-displacement curves (AFM) were found to agree with the predictions of the Derjaguin-Muller-Toporov (DMT) theory. The JKR equation used in the interpretation of the JKR experiments was modified by taking into account the differences between the surface and bulk moduli of the ITO-coated poly(dimethylsiloxane) (PDMS) lens. The ratio of the surface modulus to the bulk modulus we used in this modified JKR equation was obtained by determining the slope of the attracting part of the force-displacement curve. The values of the work of adhesion calculated using the modified JKR equation were also found to agree with the values obtained from contact angle measurements. We conclude that the two methods using AFM and the JKR apparatus can be used in the evaluation of the work of adhesion between inorganic materials with high surface energies such as metal and metal oxide surfaces.

Coherent x-rays from synchrotron sources are increasingly used in non-conventional radiological techniques ('phase-contrast' radiology). Our experiments demonstrate that by using white (unmonochromatic) radiation and a time-resolving system, it is possible to image microscopic details of moving blood vessels in different live animals without using any contrast agent. The images have excellent contrast plus unprecedented spatial resolution for microangiography (10 microm). This result is likely to impact many different areas of biological and medical research and of diagnostic radiology.