Selection of Wavelet Filters for Panoramic Dental X-Ray Image Compression

The energy spectrum of an X-ray tube plays an important role in computed tomography (CT), and is often estimated from physical measurement of dedicated phantoms. Usually, this estimation problem is reduced to solving a system of linear equations, which is generally ill-conditioned. In this paper, we optimize a phantom design to find the most effective combinations of thicknesses for different materials. First, we analyze the ill-posedness of the energy spectrum inversion when the number of unknown variables (N) and measurements (M) are equal, and show the condition number of the system matrix increases exponentially with N if the transmission thicknesses are linearly changed. Then, we present a genetic optimization algorithm to minimize the condition number of the system matrix in a general case (M < N) with respect to the selection of thicknesses and types of phantom materials. Finally, in the simulation with Poisson noise we study the accuracy of the spectrum estimation using the expectation-maximum algorithm. Our results indicate that the proposed method allows high-quality spectrum estimation, and the number of measurements is reduced over two thirds of that required by the widely-used method using a phantom with linearly-changed thicknesses.

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Selection of target elements for laser-produced plasma soft x-ray sources

Optics Letters ◽

10.1364/ol.43.002042 ◽

2018 ◽

Vol 43 (9) ◽

pp. 2042 ◽

Cited By ~ 6

Author(s):

Toshiki Tamura ◽

Goki Arai ◽

Yoshiki Kondo ◽

Hiroyuki Hara ◽

Tadashi Hatano ◽

...

Keyword(s):

X Ray ◽

Laser Produced Plasma ◽

Selection Of

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Examination of a Selection of the Patent Medicines and Nostrums at the Henry Ford Museum via Energy Dispersive X-ray Fluorescence Spectrometry

ACS Symposium Series - Chemistry of Food, Food Supplements, and Food Contact Materials: From Production to Plate ◽

10.1021/bk-2014-1159.ch007 ◽

2014 ◽

pp. 87-97 ◽

Cited By ~ 2

Author(s):

Andrew Diefenbach ◽

Danielle Garshott ◽

Elizabeth MacDonald ◽

Thomas Sanday ◽

Shelby Maurice ◽

...

Keyword(s):

Energy Dispersive ◽

Fluorescence Spectrometry ◽

X Ray ◽

Patent Medicines ◽

Henry Ford ◽

Selection Of

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Recollimation shocks in relativistic jets

International Journal of Modern Physics D ◽

10.1142/s021827181844011x ◽

2018 ◽

Vol 27 (10) ◽

pp. 1844011 ◽

Cited By ~ 1

Author(s):

José M. Martí ◽

Manel Perucho ◽

José L. Gómez ◽

Antonio Fuentes

Keyword(s):

Magnetic Fields ◽

Numerical Simulations ◽

Theoretical Background ◽

Synchrotron Emission ◽

Relativistic Jets ◽

Dominant Type ◽

X Ray ◽

Extragalactic Jets ◽

X Ray Binaries ◽

Selection Of

Recollimation shocks (RS) appear associated with relativistic flows propagating through pressure mismatched atmospheres. Astrophysical scenarios invoking the presence of such shocks include jets from AGNs and X-ray binaries and GRBs. We shall start reviewing the theoretical background behind the structure of RS in overpressured jets. Next, basing on numerical simulations, we will focus on the properties of RS in relativistic steady jets threaded by helical magnetic fields depending on the dominant type of energy. Synthetic radio maps from the simulation of the synchrotron emission for a selection of models in the context of parsec-scale extragalactic jets will also be discussed.

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Solidified Fillings of Nanopores

MRS Proceedings ◽

10.1557/proc-876-r3.1 ◽

2005 ◽

Vol 876 ◽

Author(s):

Patrick Huber ◽

Klaus Knorr

Keyword(s):

Pore Diameter ◽

Stacking Faults ◽

Pore Geometry ◽

X Ray Diffraction ◽

X Ray ◽

Medium Length ◽

Close Packed Structure ◽

Packed Structure ◽

Diffraction Patterns ◽

Selection Of

AbstractWe present a selection of x-ray diffraction patterns of spherical (He, Ar), dumbbell- (N2, CO), and chain-like molecules (n-C9H20, n-C19H40) solidified in nanopores of silica glass (mean pore diameter 7nm). These patterns allow us to demonstrate how key principles governing crystallization have to be adapted in order to accomplish solidification in restricted geometries. 4He, Ar, and the spherical close packed phases of CO and N2 adjust to the pore geometry by introducing a sizeable amount of stacking faults. For the pore solidified, medium-length chainlike n-C19H40 we observe a close packed structure without lamellar ordering, whereas for the short-chain C9H20 the layering principle survives, albeit in a modified fashion compared to the bulk phase.

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Overview radiography of abdominal organs in dogs and cats

Veterinariya, Zootekhniya i Biotekhnologiya ◽

10.36871/vet.zoo.bio.202004001 ◽

2020 ◽

Vol 1 (4) ◽

pp. 6-14

Author(s):

V. N. Baymatov ◽

◽

A. V. Metelev ◽

Keyword(s):

Barium Sulfate ◽

Bile Ducts ◽

Individual Characteristics ◽

Correct Selection ◽

X Ray ◽

Abdominal Organs ◽

Modern Methods ◽

Extrahepatic Bile Ducts ◽

Selection Of

Today, less attention has been paid to x-ray studies of animals in connection with the advent of more modern methods. At the same time, the quality of radiopaque substances decreased, which is reflected in this article. The Omnipack, Urografin, Visipack, Barium sulfate, Iodipamide, Bilignost and Biligrafin used in radiopaque contrast studies in most cases did not reveal the hepatobiliary system. Only the last two drugs gave satisfactory results. The complexity of the X-ray examination of the biliary system in cats and dogs lies in the features of the location of the extrahepatic bile ducts and the condition of the intestine, the size of the liver, its structure, echogenicity, the state of the vessels and surrounding organs. In this work, we took into account the anatomical variants of the development and location of organs in animals, which may complicate the study or evaluation of the data obtained. These included changes in the contours, shape, location of the gallbladder and its filling. The results obtained were compared with the available general species standards, taking into account the possible individual characteristics of each animal. Other studied drugs gave satisfactory results with an overall assessment of the abdominal organs, but we preferred Omnipack. Survey radiography provides a large amount of information with the correct selection of radiopaque substances.

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Diffracted Beam Monochromators for Powder Diffractometry

Advances in X-ray Analysis ◽

10.1154/s0376030800008272 ◽

1970 ◽

Vol 14 ◽

pp. 38-56

Author(s):

E. M. Proctor ◽

T. C. Furnas ◽

W. F. Loranger

Keyword(s):

Preferred Orientation ◽

Signal To Noise ◽

X Ray ◽

Direct Beam ◽

Vertical Divergence ◽

Oriented Samples ◽

Efficiency And Effectiveness ◽

Slit System ◽

Bent Crystals ◽

Selection Of

AbstractThe efficiency and effectiveness of diffracted beam x-ray monochromators used in powder diffractometry have been described in so many ways that much confusion exists regarding their true performance. Although significant improvements in signal to noise ratios are readily achievable, and they offer a solution to the sample fluorescence problem, it is not without sacrifice to total intensity or achievable resolution or both. This paper discusses and describes a series of comparisons between filtered direct beam, LiF and graphite monochromators.These comparisons include the considerations necessary for the appropriate selection of diffracted beam slit system, the effect of vertical divergence as a function of two theta for singly bent crystals, the effects of a non-uniformity of contribution over the length of the crystal, and the geometry necessary for the singly bent and doubly bent crystals. The total intensity and the resolution of LiF and graphite are discussed, in particular, it is noted that the performance of monochromators with randomly oriented samples is quite different than their performance with samples showing preferred orientation or grain effects.A new diffracted beam monochromator based on the Rowland focusing geometry is described.

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