In the conventional X-ray imaging, the ray image of the complicated structural component (shape, structure complex and multi-materials) easily exhibits the overexposed and underexposed phenomenon. This is because of the bigger variations in the effective thickness in the orientation of X-ray penetration and the limit of the dynamic range of X-ray imaging system. The complete structure information can't be obtained, and it will impact the quality of X-ray CT image. So the present paper has improved the theory and method of variable voltage X-ray multi-spectrum CT imaging. The new method changes the distribution of X-ray spectrum by changing the voltage, and can realize the matching between the X-ray spectrum and the effective thickness of workpieces. This can expand the dynamic range and ensure the integrity of projection about the workpieces. At the same time, based on the idea of virtual design, the paper has built the variable voltage virtual CT mode based on single-energy and multi-energy, and realized virtual simulation of the variable voltage X-ray CT. At last, the virtual experiment has proved that the theory and method of variable voltage CT imaging is feasible, and the variable voltage CT imaging is the effective method for the complicated structural component.
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Biochem Biophys Res Commun
December 2024
Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto, 603-8555, Japan. Electronic address:
Pannexin-3 (PANX3) is a member of the pannexin family of large-pore, ATP-permeable channels conserved across vertebrates. PANX3 contributes to various developmental and pathophysiological processes by permeating ATP and Ca ions; however, the structural basis of PANX3 channel function remains unclear. Here, we present the cryo-EM structure of human PANX3 at 2.
View Article and Find Full Text PDFNanotechnology
December 2024
Instituto de Nanociencia y Nanotecnología (CONICET-CNEA), Gral. Paz 1499 - San Martín - Argentina, BUENOS AIRES, 1650, ARGENTINA.
Our study demonstrates that strong cationic segregation can occur in amorphous complex oxide memristors during electrical operation. With the help of analytic techniques, we observed that switching the electrical stimulation from voltage to current significantly prevents structural changes and cation segregation at the nanoscale, improving also the device cycle-to-cycle variability. These findings could contribute to the design of more reliable oxide-based memristors and underscore the crucial effect that has the type of electrical stimulation applied to the devices on their integrity and reliability.
View Article and Find Full Text PDFACS Meas Sci Au
December 2024
Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis 55455, Minnesota, United States.
The diversification of electronic materials in devices provides a strong incentive for methods to rapidly correlate device performance with fabrication decisions. In this work, we present a low-cost automated test station for gated electronic transport measurements of field-effect transistors. Utilizing open-source PyMeasure libraries for transparent instrument control, the "ATLAS-MAP" system serves as a customizable interface between sourcemeters and samples under test and is programmed to conduct transfer curve and van der Pauw methods with static and sweeping gate voltages.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Instituto de Tecnología Química (Universitat Politècnica de València-Agencia Estatal Consejo Superior de Investigaciones Científicas), Av. dels Tarongers, 46022, València, Spain.
Memristors stand out as promising components in the landscape of memory and computing. Memristors are generally defined by a conductance mechanism containing a state variable that imparts a memory effect. The current-voltage cycling causes transitions of conductance, which are determined by different physical mechanisms, such as the formation of conducting filaments in an insulating surrounding.
View Article and Find Full Text PDFBiophys J
December 2024
I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry Russian Academy of Sciences, St. Petersburg, Russia; Department of Biochemistry and Biomedical Sciences, Master University, Hamilton, Canada. Electronic address:
Despite their large functional diversity and poor sequence similarity, tetrameric and pseudo-tetrameric potassium, sodium, calcium and cyclic-nucleotide gated channels, as well as two-pore channels, transient receptor potential channels and ionotropic glutamate receptors share a common folding pattern of the transmembrane (TM) helices in the pore-forming domain. In each subunit or repeat, the pore domain has two TM helices connected by a membrane-reentering P-loop. The P-loop includes a membrane-descending helix, P1, which is structurally the most conserved element of these channels, and residues that contribute to the selectivity-filter region at the constriction of the ion-permeating pathway.
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