Abstract：
:It is well known that harmonic bounded Gaussian beams undergo a transformation into two bounded beams upon reflection on a solid immersed in a liquid. The effect is known as the Schoch effect and can be found at the Rayleigh angle for thick plates and at the different Lamb angles for thin plates. Here, a study is made on the effect of pulsed Gaussian beams reflected on solids. It is found experimentally that the Rayleigh wave phenomenon still generates two reflected bounded beams, whereas Lamb wave phenomena do not generate this effect. This fact may be explained intuitively by realizing that the Rayleigh phenomenon is a coincidental phenomenon that is generated in situ, whereas the Lamb wave phenomenon is a non-coincidental phenomenon that is generated only after incident sound is influenced by both sides of a thin plate. Another explanation is the fact that Rayleigh waves are not dispersive, whereas stimulation and propagation of Lamb waves is frequency dependent. A pulse contains many frequencies and therefore only a fraction of the incident pulse is transformed into a Lamb wave. In this paper, numerical simulations are performed that show that actually the Schoch effect does occur neither for Rayleigh waves, nor for Lamb waves. As a matter of fact, a pulse, incident at the Rayleigh angle, generates two reflected lobes with a null zone of a different kind. The null zone is beating several times during the passage of each pulse. This results in a 'null zone' having a lower mean intensity than any of the two lobes, still less outspoken than for the case of harmonic incident bounded beams. This effect does only occur for Rayleigh wave generation and is much less outspoken for Lamb wave generation.
journal_name
Ultrasonicsjournal_title
Ultrasonicsauthors
Declercq NFdoi
10.1016/j.ultras.2006.05.205subject
Has Abstractpub_date
2006-12-22 00:00:00pages
e1447-51eissn
0041-624Xissn
1874-9968pii
S0041-624X(06)00221-6journal_volume
44 Suppl 1pub_type
杂志文章相关文献
ULTRASONICS文献大全abstract：:Ultrasonic flaw classification in weldment is an active area of research and many artificial intelligence approaches have been applied to automate this process. However, in the industrial applications, the ultrasonic flaw signals are not noise free and automatic intelligent defect classification algorithms show relati...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2018.12.001
更新日期：2019-04-01 00:00:00
abstract：:The microwave ablation has become an important manner for tumor treatment. In this paper, we proposed a new method for evaluation of microwave-induced thermal lesions using the wavelet analysis of the mean scatterer spacing (MSS). First, the ultrasonic radiofrequency (RF) data of normal and coagulated porcine liver ti...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2013.03.018
更新日期：2013-09-01 00:00:00
abstract：:The objective of this study was to examine the potential of ultrasonic velocity as a rapid and nondestructive method to predict the dimensional stability of oak (Quercus petraea (Mattuschka) Lieblein) and chestnut (Castanea sativa Mill.) that are commonly used in flooring industry. Ultrasonic velocity, specific gravit...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2015.11.007
更新日期：2016-03-01 00:00:00
abstract：:This paper investigates the dependence of ultrasonic velocity in rabbit liver on the water content and tissue structure. The results obtained indicate that the composition and water content of the liver tissue but not its structure determine the value of velocity. ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/0041-624x(87)90040-0
更新日期：1987-07-01 00:00:00
abstract：:Today, sophisticated instruments and algorithms used for process control allow the efficient production of substances with the quality guaranteed to the customer. However, production and management techniques are changing. This article aims to analyze trends resulting from those changes from the point of view of ultra...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2006.05.047
更新日期：2006-12-22 00:00:00
abstract：:Images captured during routine clinical transcranial sonography (TCS) examination are of a low resolution, so can be confusing for diagnostic evaluations. Manual segmentation of brain structures (areas of the midbrain and substantia nigra (SN)) that are of special interest cause inter-observer and intra-observer varia...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2012.04.005
更新日期：2013-01-01 00:00:00
abstract：:The purpose of this study is to evaluate whether a 5-repetition liver stiffness (LS) measurement as the standard protocol of shear wave elastography (SWE) is comparable to a conventional 10-repetition measurement protocol and to identify factors that influence the reliability of the 5-repetition protocol. A total of 3...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2016.08.005
更新日期：2016-12-01 00:00:00
abstract：:In this paper, we investigated theoretically and experimentally the effect of the conductivity of the film located in the immediate vicinity of the free side of a piezoelectric resonator based on the PZT ceramics on its characteristics. It is shown that with increasing the conductivity of the film at first the paralle...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2018.09.016
更新日期：2019-04-01 00:00:00
abstract：:Single clouds of cavitation bubbles, driven by 254kHz focused ultrasound at pressure amplitudes in the range of 0.48-1.22MPa, have been observed via high-speed shadowgraphic imaging at 1×10(6) frames per second. Clouds underwent repetitive growth, oscillation and collapse (GOC) cycles, with shock-waves emitted periodi...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2014.06.011
更新日期：2014-12-01 00:00:00
abstract：:It is shown that a diffuse field is not devoid of phase information, but has a correlation function equal to the Green's function. More specifically, the cross-correlation between diffuse signals in two transducers is very nearly equal to the direct response of one transducer to an impulse applied to the other. This i...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/s0041-624x(02)00156-7
更新日期：2002-05-01 00:00:00
abstract：:Features of an acoustic energy trapping and outflow in a High-overtone Bulk Acoustic Resonator (HBAR) were considered. On the example of a specified resonator based on a piezoelectric layered structure (PLS) as "Al/AlN/Mo/(100) diamond", the simulation of the propagation of microwave acoustic waves in the range of 10-...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2020.106311
更新日期：2021-03-01 00:00:00
abstract：:Periodic composite ultrasonic transducers offer many advantages but the periodic pillar architecture can give rise to unwanted modes of vibration which interfere with the piston like motion of the fundamental thickness mode. In this paper, viscoelastic loss is incorporated into a three-dimensional plane wave expansion...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2008.03.004
更新日期：2008-12-01 00:00:00
abstract：:The objective was to use multiple paths through the slurry to determine the lowest concentration that provided accurate attenuation measurements and to measure the velocity of sound through an effective long path. Ultrasonic attenuation measurements were obtained for slurries of silica (10 microm diameter) in water fo...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2006.05.024
更新日期：2006-12-22 00:00:00
abstract：:An ultrasonic method of acoustic parameter evaluation for porous materials saturated by air (or any other gas) is discussed. The method is based on the evolution of speed of sound and the attenuation inside the material when the static pressure of the gas saturating the material is changed. Asymptotic development of t...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/s0041-624x(00)00062-7
更新日期：2001-04-01 00:00:00
abstract：:The present study focuses on a possibility for improving NO removal efficiency from flue gas by application of powerful sound waves. The sound waves (frequency 6.9-17.2kHz, intensity 144-160dB) are propagated from Hartmann sound generators to a preheated graphite disk inside a vertical reaction tube (height 1.8m, I.D....
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2004.06.010
更新日期：2005-02-01 00:00:00
abstract：:The purpose of this research was to develop, implement and verify a measurement technique enabling rapid and dependable characterization of ultrasound hydrophone probes beyond 20 MHz. The technique employs focused acoustic sources to optimize signal-to-noise ratio and spatial averaging correction model to account for ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/s0041-624x(02)00166-x
更新日期：2002-05-01 00:00:00
abstract：:The Lamb waves are used for the ultrasonic characterization of welds because of their relative long-range propagation. In this paper, a simplified model of a weld-strip between two identical semi-infinite elastic layers is investigated. The reflected and transmitted ultrasonic fields are expressed by modal series whos...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2004.11.004
更新日期：2005-06-01 00:00:00
abstract：:This study aims to bridge the gap between transport mechanisms of an improved ultrasound contrast agent (UCA) and its resulting behavior in a clinical imaging study. Phospholipid-shelled microbubbles nested within the aqueous core of a polymer microcapsule are examined for their use and feasibility as an improved UCA....
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2014.06.019
更新日期：2014-12-01 00:00:00
abstract：:An approximate formula has been developed to determine the electromechanical coupling coefficient of the piezoelectric film in a four-layer composite resonator, which includes two electrodes. In this formula, the coupling coefficient can be calculated from the distribution of the effective coupling coefficients, k2eff...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/s0041-624x(99)00172-9
更新日期：2000-03-01 00:00:00
abstract：:Chemical mechanical polishing (CMP) is the primary method to realize the global planarization of silicon wafer. In order to improve this process, a novel method which combined megasonic vibration to assist chemical mechanical polishing (MA-CMP) is developed in this paper. A matching layer structure of polishing head w...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2017.04.005
更新日期：2017-09-01 00:00:00
abstract：:Ultrasonic vibration has been observed to lower the flow stress necessary to initiate plastic deformation, a phenomenon known as "acoustic softening". This unique effect of ultrasound has been extensively applied in welding, machining, forming of metals, and ultrasonic additive manufacturing to lower the yield stress ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2019.106005
更新日期：2020-03-01 00:00:00
abstract：:One of the important issues in the field of ultrasound medical imaging using contrast agents is the development of techniques able to separate the response of the contrast media from that of the biological tissues. In the literature, one can find various solutions involving the use of multiple transmitted signals and ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2008.05.008
更新日期：2009-01-01 00:00:00
abstract：:This work was devoted to the development of a health monitoring system assigned to aerospace applications. Those applications concerned the detection of damaging impacts and debonding between stiffeners and composite skins, since they are the major causes of in-service damage of aircraft structures. The chosen health ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2004.01.058
更新日期：2004-04-01 00:00:00
abstract：:This paper will describe the application of a finite element (FE) code to design a test cell, in which a single transducer is used to generate acoustic cavitation. The FE model comprises a 2-D slice through the centre of the test cell and was used to evaluate the generated pressure fields as a function of frequency. I...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/s0041-624x(02)00453-5
更新日期：2003-06-01 00:00:00
abstract：:This paper deals with the influence of gas law on ultrasonic behaviour of porous media when the saturating fluid is high pressured. Previous works have demonstrated that ultrasonic transmission through a porous sample with variations of the static pressure (up to 18 bars) of the saturating fluid allows the characteriz...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2010.02.003
更新日期：2010-06-01 00:00:00
abstract：:The paper deals with the study of the resonances of 1D periodic media composed of N elementary cells formed with two perfectly bonded layers which exhibit a high acoustic impedance contrast. In the case of a periodic bilayer structure constituted of a fluid layer and an elastic plate, it was shown in previous theoreti...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2012.11.011
更新日期：2013-03-01 00:00:00
abstract：MOTIVATION:Commercial ultrasound machines in the past did not provide the ultrasound researchers access to raw ultrasound data. Lack of this ability has impeded evaluation and clinical testing of novel ultrasound algorithms and applications. OBJECTIVES:Recently, we developed a flexible ultrasound back-end where all th...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2007.11.009
更新日期：2008-07-01 00:00:00
abstract：BACKGROUND:Generalized coherence factor (GCF) can be adaptively estimated from channel data to suppress sidelobe artifacts. Conventionally, Fast Fourier Transform (FFT) is utilized to calculate the full channel spectrum and suffers from high computation load. In this work, autocorrelation (AR)-based algorithm is utiliz...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2016.07.015
更新日期：2016-12-01 00:00:00
abstract：:A nonlinear ultrasonic method is proposed based on a group of newly discovered wave triplets where two primary codirectional shear-horizontal SH0 waves mix in a weakly nonlinear plate and generate a cumulative S0 Lamb wave at the sum frequency. Theoretical analyses show that any combination of two primary SH0 waves wh...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2019.04.001
更新日期：2019-07-01 00:00:00
abstract：:Accurate characterization of the characteristic dimensions of a periodically corrugated surface using ultrasonic imaging technique is investigated both theoretically and experimentally. The possibility of accurately characterizing the characteristic dimensions is discussed. The condition for accurate characterization ...
journal_title：Ultrasonics
pub_type： 杂志文章
doi：10.1016/j.ultras.2012.12.006
更新日期：2013-04-01 00:00:00
