Frequency: Quarterly E- ISSN: 2277-8314 P- ISSN: Awaited Abstracted/ Indexed in: Ulrich's International Periodical Directory, Google Scholar, SCIRUS, Genamics JournalSeek, EBSCO Information Services
Inventi Impact: X-Ray Optics and Instrumentation is a peer reviewed journal focusing in the areas of x-ray optics, sources, detectors, and systems. The journal encourages research and review papers belonging the research and development for various application areas of X-Rays including medical instruments, synchrotron, solid state physics, and astronomy.
The paper presents the use of micro-X-ray computed tomography (CT) system and associated automatic loading device in visualizing and analyzing the propagation of penny-shaped flaw in gypsum-like 3D printing specimen. During the loading process, a micro-X-ray computed tomography (CT) system was used to scan the specimen with a resolution of 30 × 30 μm2. The volumetric images of specimen were reconstructed based on two-dimensional images. Thus, the propagation of penny-shaped flaw in gypsum-like 3D printing specimen in spatial was observed. The device can record the evolution of the internal pennyshaped flaw by X-ray CTscanning and the evolution of the surface crack by digital radiography at the same time. Fractal analysis was employed to quantify the cracking process. Two- and three-dimensional box-counting methods were applied to analyze slice images and volumetric images, respectively. Comparison between fractal dimensions calculated from two- and three-dimensional box-counting method was carried out. The results show that the fractal dimension increases with the propagation of cracks. Moreover, the common approach to obtain the 3D fractal dimension of a self-similar fractal object by adding one to its corresponding 2D fractal dimension is found to be inappropriate....
X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrickââ?¬â??Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10ââ?¬â?°keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20ââ?¬â?°h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles....
In accreting neutron star (NS) low-mass X-ray binaries (LMXBs), the turbulent flow in accretion\ndisk may show magnetic structures. Its emission will vary in time due to inhomogeneous motions\nthrough and with the accretion flow. These emissions contribute to considerable X-ray variability\non a wide range of timescales in all wavelengths, and down to milliseconds. In this article, we give\na brief review for quasi-periodic oscillations (QPOs), one of a periodic X-ray variability, in NS/\nLMXBs. Firstly, we give a brief introduction to NS/LMXBs and the fruitful QPO components. As an\nexample, the energy dependence of normal branch oscillations in Scorpius X-1 is discussed. We\nmostly focus on the properties and mechanism of kilohertz QPOsââ?¬â?the fastest variability components\nthat have the same order as the dynamical timescales of the innermost regions of accretion\nflow. Finally, we discuss the success and questions for theoretical interpretations and present the\npossible entry for investigation of nature of QPOs....
We present the first Chandra X-ray Observatory (CXO) catalog of “pulsar X-ray filaments,” or “misaligned outflows.” These are linear, synchrotron-radiating features powered by ultrarelativistic electrons and positrons that escape from bow shock pulsars. The filaments are misaligned with the (large) pulsar velocity, distinguishing them from the pulsar wind nebula (PWN) trail, which is also often visible in CXO ACIS images. Spectral fits and morphological properties are extracted for five secure filaments and three candidates using a uniform method. We present a search of archival CXO data for linear diffuse features; the known examples are recovered and a few additional weak candidates are identified. We also report on a snapshot CXO ACIS survey of pulsars with properties similar to the filament producers, finding no new filaments but some diffuse emission, including one PWN trail. Finally, we provide an updated model for the pulsar properties required to create filaments in light of these new observations....
Active galactic nuclei (AGN) produce the highest intrinsic luminosities in the Universe\nfrom within a compact region. The central engine is thought to be powered by accretion onto a\nsupermassive black hole. A fraction of this huge release of energy influences the evolution of the\nhost galaxy, and in particular, star formation. Thus, AGN are key astronomical sources not only\nbecause they play an important role in the evolution of the Universe, but also because they constitute\na laboratory for extreme physics. However, these objects are under the resolution limit of current\ntelescopes. Polarimetry is a unique technique capable of providing us with information on physical\nAGN structures. The incoming new era of X-ray polarimetry will give us the opportunity to explore\nthe geometry and physical processes taking place in the innermost regions of the accretion disc.\nHere we exploit this future powerful tool in the particular case of changing-look AGN, which are key\nfor understanding the complexity of AGN physics....
This work is aimed at studying asymmetric (BaTiO3..........
We report on the application of a short working distance von Hamos geometry spectrometer\nto measure the inelastic X-ray scattering (IXS) signals from solids and liquids. In contrast to typical\nIXS instruments where the spectrometer geometry is fixed and the incoming beam energy is scanned,\nthe von Hamos geometry allows measurements to be made using a fixed optical arrangement with\nno moving parts. Thanks to the shot-to-shot capability of the spectrometer setup, we anticipate its\napplication for the IXS technique at X-ray free electron lasers (XFELs). We discuss the capability of\nthe spectrometer setup for IXS studies in terms of efficiency and required total incident photon flux\nfor a given signal-to-noise ratio. The ultimate energy resolution of the spectrometer, which is a key\nparameter for IXS studies, was measured to the level of 150 meV at short crystal radius thanks to the\napplication of segmented crystals for X-ray diffraction. The short working distance is a key parameter\nfor spectrometer efficiency that is necessary to measure weak IXS signals....
Plasminogen (Plg) is the inactive form of plasmin (Plm) that exists in two major glycoforms, referred to as glycoforms I and II (GI and GII). In the circulation, Plg assumes an activation-resistant “closed” conformation via interdomain interactions and is mediated by the lysine binding site (LBS) on the kringle (KR) domains. These inter-domain interactions can be readily disrupted when Plg binds to lysine/arginine residues on protein targets or free L-lysine and analogues. This causes Plg to convert into an “open” form, which is crucial for activation by host activators. In this study, we investigated how various ligands affect the kinetics of Plg conformational change using small-angle X-ray scattering (SAXS).We began by examining the open and closed conformations of Plg using sizeexclusion chromatography (SEC) coupled with SAXS. Next, we developed a high-throughput (HTP) 96-well SAXS assay to study the conformational change of Plg. This method enables us to determine the Kopen value, which is used to directly compare the effect of different ligands on Plg conformation. Based on our analysis using Plg GII, we have found that the Kopen of ε-aminocaproic acid (EACA) is approximately three times greater than that of tranexamic acid (TXA), which is widely recognized as a highly effective ligand. We demonstrated further that Plg undergoes a conformational change when it binds to the C-terminal peptides of the inhibitor α2-antiplasmin (α2AP) and receptor Plg–RKT. Our findings suggest that in addition to the C-terminal lysine, internal lysine(s) are also necessary for the formation of open Plg. Finally, we compared the conformational changes of Plg GI and GII directly and found that the closed form of GI, which has an N-linked glycosylation, is less stable. To summarize, we have successfully determined the response of Plg to various ligand/receptor peptides by directly measuring the kinetics of its conformational changes....
The inverse-Compton X-ray emission model for supernovae has been well established to explain the X-ray properties of many supernovae for over 30 years. However, no observational case has yet been found to connect the X-rays with the optical lights as they should be. Here, we report the discovery of a hard X-ray source that is associated with a Type II-b supernova. Simultaneous emission enhancements have been found in both the X-ray and optical light curves twenty days after the supernova explosion. While the enhanced X-rays are likely dominated by inverse-Compton scatterings of the supernova's lights from the Type II-b secondary peak, we propose a scenario of a high-speed supernova ejecta colliding with a low-density pre-supernova stellar wind that produces an optically thin and high-temperature electron gas for the Comptonization. The inferred stellar wind mass-loss rate is consistent with that of the supernova progenitor candidate as a yellow supergiant detected by the Hubble Space Telescope, providing an independent proof for the progenitor. This is also new evidence of the inverse-Compton emission during the early phase of a supernova....
Background: The high-resolution X-ray imaging system employing synchrotron\nradiation source, thin scintillator, optical lens and advanced CCD camera can achieve\na resolution in the range of tens of nanometers to sub-micrometer. Based on this\nadvantage, it can effectively image tissues, cells and many other small samples,\nespecially the calcification in the vascular or in the glomerulus. In general, the\nthickness of the scintillator should be several micrometers or even within\nnanometers because it has a big relationship with the resolution. However, it is\ndifficult to make the scintillator so thin, and additionally thin scintillator may greatly\nreduce the efficiency of collecting photons.\nMethods: In this paper, we propose an approach to extend the depth of focus\n(DOF) to solve these problems. We develop equation sets by deducing the\nrelationship between the high-resolution image generated by the scintillator and the\ndegraded blur image due to defect of focus first, and then we adopt projection onto\nconvex sets (POCS) and total variation algorithm to get the solution of the equation\nsets and to recover the blur image.\nResults: By using a 20 �¼m thick un matching scintillator to replace the 1 �¼m thick\nmatching one, we simulated a high-resolution X-ray imaging system and got a\ndegraded blur image. Based on the algorithm proposed, we recovered the blur\nimage and the result in the experiment showed that the proposed algorithm has\ngood performance on the recovery of image blur caused by un matching thickness\nof scintillator.\nConclusions: The method proposed is testified to be able to efficiently recover the\ndegraded image due to defect of focus. But, the quality of the recovery image\nespecially of the low contrast image depends on the noise level of the degraded\nblur image, so there is room for improving and the corresponding denoising\nalgorithm is worthy for further study and discussion....
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