نتایج جستجو برای: heterogeneous slab phantom

تعداد نتایج: 152537  

2015
Qing-yuan Xu Bin Yan Ping Lou Xiao-lin Zhou

A subway train-steel spring floating slab track-tunnel coupling dynamic model, considering short and middle-long wavelength random track irregularities, and longitudinal connection between adjacent slabs of steel spring floating slab track, was developed. And the influence of slab length on dynamic characteristics of the system under different track conditions and train speeds are theoretically...

2003
Paule M. Charland Indrin J. Chetty Shigeru Yokoyama Benedick A. Fraass

In this study, a dosimetric evaluation of the new Kodak extended dose range (EDR) film versus ionization measurements has been conducted in homogeneous solid water and water-lung equivalent layered heterogeneous phantoms for a relevant range of field sizes (up to a field size of 25x25 cm2 and a depth of 15 cm) for 6 and 15 MV photon beams from a linear accelerator. The optical density of EDR fi...

Journal: :Journal of biomedical optics 2012
Chao Huang Liming Nie Robert W Schoonover Lihong V Wang Mark A Anastasio

We report an investigation of image reconstruction in photoacoustic tomography for objects that possess heterogeneous material and acoustic attenuation distributions. When the object contains materials, such as bone and soft-tissue, that are modeled using power law attenuation models with distinct exponents, we demonstrate that the effects of acoustic attenuation due to the most strongly attenu...

2004
Clinton P. Conrad Carolina Lithgow-Bertelloni

[1] Although mantle slabs ultimately drive plate motions, the mechanism by which they do so remains unclear. A detached slab descending through the mantle will excite mantle flow that exerts shear tractions on the base of the surface plates. This ‘‘slab suction’’ force drives subducting and overriding plates symmetrically toward subduction zones. Alternatively, cold, strong slabs may effectivel...

Journal: :Nuclear Technology & Radiation Protection 2022

Advances of radiation delivery devices have increased the complexity oncology treatments. Herewith, outcome treatment, as well patient safety, strongly depend on consistency absorbed dose delivery. Both can be ensured by comprehensive system verification calculated distributions. Standard method is evaluation distribution according to gamma method, using a 2-D detector and homogeneous phantom, ...

At present, reducing subgrade settlement of soft soil foundation is a key problem in high-speed railway construction. Pile-slab structure is a widely-utilized form of foundation structure to reduce the subgrade settlement in China. In order to save the engineering cost for high-speed railway construction in developing countries, the author developed a pile-slab structure and named it as the new...

2014
Jochen Moll Thomas N. Kelly Dallan Byrne Mantalena Sarafianou Viktor Krozer Ian James Craddock

Conventional radar-based image reconstruction techniques fail when they are applied to heterogeneous breast tissue, since the underlying in-breast relative permittivity is unknown or assumed to be constant. This results in a systematic error during the process of image formation. A recent trend in microwave biomedical imaging is to extract the relative permittivity from the object under test to...

Journal: :Ultrasonic imaging 2003
E L Madsen G R Frank T A Krouskop T Varghese F Kallel J Ophir

A ten-month study is presented of materials for use in heterogeneous elastography phantoms. The materials consist of gelatin with or without a suspension of microscopic safflower oil droplets. The highest volume percent of oil in the materials is 50%. Thimerosal acts as a preservative. The greater the safflower oil concentration, the lower the Young's modulus. Elastographic data for heterogeneo...

Journal: :Biomedical optics express 2014
Baoqiang Li Foued Maafi Romain Berti Philippe Pouliot Eric Rhéaume Jean-Claude Tardif Frederic Lesage

Combining Fluorescent Molecular Tomography (FMT) with anatomical imaging, e.g. MRI facilitates interpreting functional information. Furthermore, using a heterogeneous model for light propagation has been shown in simulations to be superior to homogeneous modeling to quantify fluorescence. Here, we present a combined FMT-MRI system and apply it to heart and aorta molecular imaging, a challenging...

Journal: :Ultrasound in medicine & biology 2007
Kenneth Hoyt Kevin J Parker Deborah J Rubens

In this paper, a novel sonoelastographic technique for estimating local shear velocities from propagating shear wave interference patterns (termed crawling waves) is introduced. A relationship between the local crawling wave spatial phase derivatives and local shear wave velocity is derived with phase derivatives estimated using an autocorrelation technique. Results from homogeneous phantoms de...

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