The Experts below are selected from a list of 8700 Experts worldwide ranked by ideXlab platform
B S Gerstman - One of the best experts on this subject based on the ideXlab platform.
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Photoacoustic generation for a spherical absorber with Impedance Mismatch with the surrounding media.
Physical Review E, 1999Co-Authors: Jinming Sun, B S GerstmanAbstract:Pressure generation in a spherical absorber due to energy deposition from pulsed lasers is studied. For a variety of conditions, analytical solutions are derived that allow quick computation of exact results. For the special case of identical acoustic Impedance, the pressure transient spreads to the surrounding medium by a single compressive pulse followed by a tensile pulse at the end of illumination. For the general case of Impedance Mismatch, the pressure transient is in the form of a series of dampened compressive and tensile pressure pulses. In this paper both the amplitude ratio and the sign of consecutive pressure pulses are determined analytically, and are shown to be dependent upon the Impedance Mismatch. For laser pulses of duration much less than the absorber's characteristic oscillation time, a stress confinement limit is reached for most of the absorber, but a sharp tensile stress in the core region of the sphere is predicted. This region of high stress is defined by $rl~{r}_{c},$ and we show that ${r}_{c}$ is proportional to the laser pulse duration ${\ensuremath{\tau}}_{0}.$ Upon further shortening of the laser pulse duration, the strength of this tensile stress continues to increase while its spatial distribution is sharpened. This observation has relevance to a number of experiments where laser-induced pressure transients cause the absorber to fracture.
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Photoacoustic generation for a spherical absorber with Impedance Mismatch with the surrounding media.
Physical review. E Statistical physics plasmas fluids and related interdisciplinary topics, 1999Co-Authors: J M Sun, B S GerstmanAbstract:Pressure generation in a spherical absorber due to energy deposition from pulsed lasers is studied. For a variety of conditions, analytical solutions are derived that allow quick computation of exact results. For the special case of identical acoustic Impedance, the pressure transient spreads to the surrounding medium by a single compressive pulse followed by a tensile pulse at the end of illumination. For the general case of Impedance Mismatch, the pressure transient is in the form of a series of dampened compressive and tensile pressure pulses. In this paper both the amplitude ratio and the sign of consecutive pressure pulses are determined analytically, and are shown to be dependent upon the Impedance Mismatch. For laser pulses of duration much less than the absorber's characteristic oscillation time, a stress confinement limit is reached for most of the absorber, but a sharp tensile stress in the core region of the sphere is predicted. This region of high stress is defined by r < or =r(c), and we show that r(c) is proportional to the laser pulse duration tau(0). Upon further shortening of the laser pulse duration, the strength of this tensile stress continues to increase while its spatial distribution is sharpened. This observation has relevance to a number of experiments where laser-induced pressure transients cause the absorber to fracture.
Erik Meijer - One of the best experts on this subject based on the ideXlab platform.
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SSDGP - Revealing the X/O Impedance Mismatch: changing lead into gold
Datatype-Generic Programming, 2007Co-Authors: Ralf Lammel, Erik MeijerAbstract:We take the term X/O Impedance Mismatch to describe the difficulty of the OO paradigm to accommodate XML processing by means of recasting it to typed OO programming. In particular, given XML types (say, XML schemas), it is notoriously difficult to map them automatically to object types (say, object models) that (i) reasonably compare to native object types typically devised by OO developers; (ii) fully preserve the intent of the original XML types; (iii) fully support round-tripping of arbitrary, valid XML data; and (iv) provide a general and convenient programming model for XML data hosted by objects. We reveal the X/O Impedance Mismatch in particular detail. That is, we survey the relevant differences between XML and objects in terms of their data models and their type systems. In this process, we systematically record and assess X-to-O mapping options. Our illustrations employ XSD (1.0) as the XML-schema language of choice and C# (1.0-3.0) as the bound of OO language expressiveness.
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there is no Impedance Mismatch language integrated query in visual basic 9
Conference on Object-Oriented Programming Systems Languages and Applications, 2006Co-Authors: Erik MeijerAbstract:Language Integrated Query (LINQ) is a framework that is rooted in the theoretical ideas of monads and monad comprehensions to allow seamless querying over objects, XML, and relational data. Instead of blindly gazing at the perceived Impedance Mismatch between the structure of these various data models, LINQ leverages the commonalities between the operations on these data models to achieve deep semantic integration.
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revealing the x o Impedance Mismatch changing lead into gold
SSDGP'06 Proceedings of the 2006 international conference on Datatype-generic programming, 2006Co-Authors: Ralf Lammel, Erik MeijerAbstract:We take the term X/O Impedance Mismatch to describe the difficulty of the OO paradigm to accommodate XML processing by means of recasting it to typed OO programming. In particular, given XML types (say, XML schemas), it is notoriously difficult to map them automatically to object types (say, object models) that (i) reasonably compare to native object types typically devised by OO developers; (ii) fully preserve the intent of the original XML types; (iii) fully support round-tripping of arbitrary, valid XML data; and (iv) provide a general and convenient programming model for XML data hosted by objects. We reveal the X/O Impedance Mismatch in particular detail. That is, we survey the relevant differences between XML and objects in terms of their data models and their type systems. In this process, we systematically record and assess X-to-O mapping options. Our illustrations employ XSD (1.0) as the XML-schema language of choice and C# (1.0-3.0) as the bound of OO language expressiveness.
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OOPSLA Companion - There is no Impedance Mismatch: (language integrated query in visual basic 9)
Companion to the 21st ACM SIGPLAN conference on Object-oriented programming systems languages and applications - OOPSLA '06, 2006Co-Authors: Erik MeijerAbstract:Language Integrated Query (LINQ) is a framework that is rooted in the theoretical ideas of monads and monad comprehensions to allow seamless querying over objects, XML, and relational data. Instead of blindly gazing at the perceived Impedance Mismatch between the structure of these various data models, LINQ leverages the commonalities between the operations on these data models to achieve deep semantic integration.
Jinming Sun - One of the best experts on this subject based on the ideXlab platform.
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Photoacoustic generation for a spherical absorber with Impedance Mismatch with the surrounding media.
Physical Review E, 1999Co-Authors: Jinming Sun, B S GerstmanAbstract:Pressure generation in a spherical absorber due to energy deposition from pulsed lasers is studied. For a variety of conditions, analytical solutions are derived that allow quick computation of exact results. For the special case of identical acoustic Impedance, the pressure transient spreads to the surrounding medium by a single compressive pulse followed by a tensile pulse at the end of illumination. For the general case of Impedance Mismatch, the pressure transient is in the form of a series of dampened compressive and tensile pressure pulses. In this paper both the amplitude ratio and the sign of consecutive pressure pulses are determined analytically, and are shown to be dependent upon the Impedance Mismatch. For laser pulses of duration much less than the absorber's characteristic oscillation time, a stress confinement limit is reached for most of the absorber, but a sharp tensile stress in the core region of the sphere is predicted. This region of high stress is defined by $rl~{r}_{c},$ and we show that ${r}_{c}$ is proportional to the laser pulse duration ${\ensuremath{\tau}}_{0}.$ Upon further shortening of the laser pulse duration, the strength of this tensile stress continues to increase while its spatial distribution is sharpened. This observation has relevance to a number of experiments where laser-induced pressure transients cause the absorber to fracture.
Steven A. Jones - One of the best experts on this subject based on the ideXlab platform.
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The influence of acoustic Impedance Mismatch on post-stenotic pulsed-Doppler ultrasound measurements in a coronary artery model.
Ultrasound in medicine & biology, 1996Co-Authors: Steven A. Jones, H. Leclerc, George P. Chatzimavroudis, Young H. Kim, N. A. Scott, Ajit P. YoganathanAbstract:Acoustic Impedance Mismatch at the fluid-wall interface was shown to affect the spectra from an intravascular Doppler device in an in vitro model with a diameter typical of human coronary arteries. Measurements were obtained first under Poiseuille flow conditions with Impedance Mismatches of 0%, 7% and 12%, and then under stenosed conditions for the 0% and 7% Mismatch cases. For the zero Mismatch case, the Doppler spectra could be readily interpreted in terms of fluid mechanical phenomena. When Mismatch was present, the spectra from Poiseuille flow exhibited multiple peaks which could not be directly related to the velocity profile. Also, the spectra from stenosed flow with a Mismatch of 7% were similar to those from the zero Mismatch case but did not exhibit the specific flow-related features as clearly. These results indicate that the Impedance Mismatch alters the acoustic environment inside the model and that this causes artifact in the Doppler spectra.
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Distortion of Doppler ultrasound beam patterns caused by acoustic Impedance Mismatch at vessel interfaces
Proceedings of 16th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1994Co-Authors: Steven A. JonesAbstract:It has been noted previously that Doppler ultrasound measurements from a coronary guidewire in a circular tube exhibited spectral peaks which were not directly related to hemodynamic phenomena. These peaks were more pronounced with an increase in the acoustic Impedance Mismatch between the tube walls and the fluid. To determine whether these peaks could be explained by Mismatch-induced beam-pattern distortion, the beam pattern of an ultrasound probe inside a circular tube was measured and was used to simulate the Doppler spectrum which would result from Poiseuille flow. The resulting spectra had peaks similar in size to those from guidewire measurements in Poiseuille flow.
Daniel M. Mittleman - One of the best experts on this subject based on the ideXlab platform.
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Study of the Impedance Mismatch at the output end of a THz parallel-plate waveguide
Applied Physics Letters, 2012Co-Authors: Marx M. Mbonye, Rajind Mendis, Daniel M. MittlemanAbstract:We study the reflection of terahertz (THz) radiation at the end of a parallel-plate waveguide (PPWG), due to the Impedance Mismatch between the propagating transverse-electromagnetic mode and the free-space background. We find that, for a PPWG with uniformly spaced plates, the reflection coefficient at the output face increases as the plate separation decreases, consistent with predictions by early low frequency ray optical theory. We also study the reflection coefficient for tapered PPWGs where the plate spacing is tapered, for which no analytical theory exists, and quantify the reflection coefficient as a function of the plate separation and the THz frequency.
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Characterizing the Impedance Mismatch at the output of a terahertz parallel-plate waveguide
2011 International Conference on Infrared Millimeter and Terahertz Waves, 2011Co-Authors: Marx M. Mbonye, Rajind Mendis, Daniel M. MittlemanAbstract:We study the Impedance Mismatch for terahertz waves propagating in a parallel-plate waveguide via the TEM mode. The Impedance Mismatch is found to depend strongly on the plate separation.
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Study of the Impedance Mismatch at the end-facet of a parallel plate waveguide operating in the THz regime
CLEO:2011 - Laser Applications to Photonic Applications, 2011Co-Authors: Marx M. Mbonye, Rajind Mendis, Daniel M. MittlemanAbstract:We study the Impedance Mismatch for terahertz waves propagating in a parallel plate waveguide via the TEM mode. The Impedance Mismatch is found to be a strong function of the plate separation.
