Y. Epelboin - Academia.edu (original) (raw)
Papers by Y. Epelboin
Acta Crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography, 1975
The X-ray intensity distribution in the incident plane for a crystal containing a straight disloc... more The X-ray intensity distribution in the incident plane for a crystal containing a straight dislocation has been computed. The trajectories of the wave fields have been drawn in the case of a planar or spherical incident wave, and it has been shown that the interaction of the defect with the X-rays gives rise to new directions of propagation, near the reflected direction. It has also been shown that the importance of this interaction decreases when the defect comes near the reflected direction.
Acta Crystallographica Section A Foundations of Crystallography, 1996
Proceedings of the 1998 IEEE International Frequency Control Symposium (Cat. No.98CH36165)
The modes of the resonators with geometries conforming to the lateral anisotropy of the plates ha... more The modes of the resonators with geometries conforming to the lateral anisotropy of the plates have many very interesting properties that result from a higher symmetry in a particular axis system. When they are excited by sectored elliptical electrodes they can a have a very reduced displacement in their central region. The modes with m-fold symmetry can be efficiently excited by the choice of the electrode parameters. In plane resonators, they can be selectively excited, in the resonators with the non-spherical contour less modes are excited than in usual plano-convex resonators. The resonators using the unspherical contours related to the lateral anisotropy can now be easily obtained using the recent technology. Both types have the potential to constitute very efficient new approaches towards resonators with reduced acoustic dissipation since their mode shapes can minimise the influence of the acoustic losses due to the energy transfer to the fixations. The bevelled resonators using such contours should also present a great interest.
Lecture Notes in Physics
ABSTRACT X-Ray topography is a powerfull method to study isolated defects in macroscopic crystals... more ABSTRACT X-Ray topography is a powerfull method to study isolated defects in macroscopic crystals. The contrast of the most common defects is rather well-known and their study may be done without a good knowledge of the dynamical theory. Very simples rules permit to everybody the use of this method. An accurate model for the deformation due to a defect may be verified by comparison of experiments and simulations. The difficulty remains the choice of this model but modelization assisted by computer will become more and more an ordinary tool in the interpretation of X-Ray topographs.
Materials Science and Engineering, 1985
X-ray topography is a non-destructive method for making defects such as dislocations, planar defe... more X-ray topography is a non-destructive method for making defects such as dislocations, planar defects and walls visible in crystalline materials. It is complementary to electron microscopy since it permits these defects to be characterized in macroscopic samples. In many cases the simulation of the images is the only means of fully understanding the contrast of the experimental topographs. Although developed as early as 1967, simulation remained a theoretical tool for a long time, since the computation of the images took much too long and was of poor quality. The rapid progress in computing facilities and better numerical algorithms now permits its use as an ordinary means for defect identification. The aim of this paper is to review the present state of development of the simulation of X-ray topographs.
World Directory of Crystallographers, 1990
2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings, 2011
This paper considers the determination of the mode shapes using x-ray topography and the applicat... more This paper considers the determination of the mode shapes using x-ray topography and the application of this method to resonant piezoelectric devices made of various materials (Quartz, LGS, Lithium tantalate). The basis of the method is recalled briefly and its application to thickness mode resonators or filters is particularly considered. A comparison of the observed mode shapes with those computed using the “essentially thickness mode” theory of H. F. Tiersten indicates that this theory give very good results concerning the modes shapes and the properties of the thickness mode devices even when materials presenting large coupling coefficients are used.
2007 IEEE International Frequency Control Symposium Joint with the 21st European Frequency and Time Forum, 2007
In this paper we apply the energy trapping theory to the extensional modes of 6 mm materials and ... more In this paper we apply the energy trapping theory to the extensional modes of 6 mm materials and particularly to piezoelectric films textured in a direction normal to the film. The 6 mm symmetries imply that the Mn' and Pn' coefficients of the Tiersten equation are equal and that energy trapping can nearly always be obtained (most often using "inverse"
2010 IEEE International Frequency Control Symposium, 2010
This paper present calculations showing the interest of to make gyroscopes that use cuts normal t... more This paper present calculations showing the interest of to make gyroscopes that use cuts normal to a three fold symmetry axis of several new materials of call 32 or 3m to build sensitive and stable gyroscopes using lateral field excitation and detection. The main factors of the sensitivity are studied and it is shown that lithium tantalate and gallium phosphate present an interesting ensemble of very favorable properties including good energy trapping properties. Experimental results have confirmed the possibility of very large Q factors
2006 IEEE International Frequency Control Symposium and Exposition, 2006
I. INTRODUCTION The mobile communication systems, the short range personal area wireless networks... more I. INTRODUCTION The mobile communication systems, the short range personal area wireless networks (WIFI, Bluetooth) and several other wireless systems such as WIMAX make a large use of UHF filters. The large number of users of these systems makes that there is a very ...
2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum, 2009
I. INTRODUCTION X-Ray topography is a very sensitive method to image strain fields in crystals. M... more I. INTRODUCTION X-Ray topography is a very sensitive method to image strain fields in crystals. Many contributions using this technique were devoted to image surface acoustic waves (SAW) in devices employing standing waves (most often SAW resonators) or progressive ...
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1995
World Directory of Crystallographers, 1995
Journal of Applied Physics, 1982
Dislocations in highly perfect quartz crystals have been characterized by correlating experimenta... more Dislocations in highly perfect quartz crystals have been characterized by correlating experimentally observed section patterns with computer simulations. The Burgers vector observed is the shortest translation vector of the quartz lattice. In cases, such as quartz, where the simple geometrical criteria fail, computer simulation methods are a powerful aid in establishing the Burgers vector of dislocations.
Journal of Applied Physics, 1979
Inhomogeneities of spin distribution are sources of magnetostrictive strains. An infinite 90° (11... more Inhomogeneities of spin distribution are sources of magnetostrictive strains. An infinite 90° (110) Bloch wall in iron for instance acts as a small angle (λ100?3.10−5 rad) twin boundary and introduces a brutal rotation of the lattice. Wall junctions create long range inhomogeneous strains (and stresses). These quantities can be analysed in terms of dislocation densities and disclinations, which may be observed experimentally by X-ray (Lang) topography. This is illustrated here for the classical Dijkstra and Martius domain structure.
Acta Crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography, 1975
The X-ray intensity distribution in the incident plane for a crystal containing a straight disloc... more The X-ray intensity distribution in the incident plane for a crystal containing a straight dislocation has been computed. The trajectories of the wave fields have been drawn in the case of a planar or spherical incident wave, and it has been shown that the interaction of the defect with the X-rays gives rise to new directions of propagation, near the reflected direction. It has also been shown that the importance of this interaction decreases when the defect comes near the reflected direction.
Acta Crystallographica Section A Foundations of Crystallography, 1996
Proceedings of the 1998 IEEE International Frequency Control Symposium (Cat. No.98CH36165)
The modes of the resonators with geometries conforming to the lateral anisotropy of the plates ha... more The modes of the resonators with geometries conforming to the lateral anisotropy of the plates have many very interesting properties that result from a higher symmetry in a particular axis system. When they are excited by sectored elliptical electrodes they can a have a very reduced displacement in their central region. The modes with m-fold symmetry can be efficiently excited by the choice of the electrode parameters. In plane resonators, they can be selectively excited, in the resonators with the non-spherical contour less modes are excited than in usual plano-convex resonators. The resonators using the unspherical contours related to the lateral anisotropy can now be easily obtained using the recent technology. Both types have the potential to constitute very efficient new approaches towards resonators with reduced acoustic dissipation since their mode shapes can minimise the influence of the acoustic losses due to the energy transfer to the fixations. The bevelled resonators using such contours should also present a great interest.
Lecture Notes in Physics
ABSTRACT X-Ray topography is a powerfull method to study isolated defects in macroscopic crystals... more ABSTRACT X-Ray topography is a powerfull method to study isolated defects in macroscopic crystals. The contrast of the most common defects is rather well-known and their study may be done without a good knowledge of the dynamical theory. Very simples rules permit to everybody the use of this method. An accurate model for the deformation due to a defect may be verified by comparison of experiments and simulations. The difficulty remains the choice of this model but modelization assisted by computer will become more and more an ordinary tool in the interpretation of X-Ray topographs.
Materials Science and Engineering, 1985
X-ray topography is a non-destructive method for making defects such as dislocations, planar defe... more X-ray topography is a non-destructive method for making defects such as dislocations, planar defects and walls visible in crystalline materials. It is complementary to electron microscopy since it permits these defects to be characterized in macroscopic samples. In many cases the simulation of the images is the only means of fully understanding the contrast of the experimental topographs. Although developed as early as 1967, simulation remained a theoretical tool for a long time, since the computation of the images took much too long and was of poor quality. The rapid progress in computing facilities and better numerical algorithms now permits its use as an ordinary means for defect identification. The aim of this paper is to review the present state of development of the simulation of X-ray topographs.
World Directory of Crystallographers, 1990
2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings, 2011
This paper considers the determination of the mode shapes using x-ray topography and the applicat... more This paper considers the determination of the mode shapes using x-ray topography and the application of this method to resonant piezoelectric devices made of various materials (Quartz, LGS, Lithium tantalate). The basis of the method is recalled briefly and its application to thickness mode resonators or filters is particularly considered. A comparison of the observed mode shapes with those computed using the “essentially thickness mode” theory of H. F. Tiersten indicates that this theory give very good results concerning the modes shapes and the properties of the thickness mode devices even when materials presenting large coupling coefficients are used.
2007 IEEE International Frequency Control Symposium Joint with the 21st European Frequency and Time Forum, 2007
In this paper we apply the energy trapping theory to the extensional modes of 6 mm materials and ... more In this paper we apply the energy trapping theory to the extensional modes of 6 mm materials and particularly to piezoelectric films textured in a direction normal to the film. The 6 mm symmetries imply that the Mn' and Pn' coefficients of the Tiersten equation are equal and that energy trapping can nearly always be obtained (most often using "inverse"
2010 IEEE International Frequency Control Symposium, 2010
This paper present calculations showing the interest of to make gyroscopes that use cuts normal t... more This paper present calculations showing the interest of to make gyroscopes that use cuts normal to a three fold symmetry axis of several new materials of call 32 or 3m to build sensitive and stable gyroscopes using lateral field excitation and detection. The main factors of the sensitivity are studied and it is shown that lithium tantalate and gallium phosphate present an interesting ensemble of very favorable properties including good energy trapping properties. Experimental results have confirmed the possibility of very large Q factors
2006 IEEE International Frequency Control Symposium and Exposition, 2006
I. INTRODUCTION The mobile communication systems, the short range personal area wireless networks... more I. INTRODUCTION The mobile communication systems, the short range personal area wireless networks (WIFI, Bluetooth) and several other wireless systems such as WIMAX make a large use of UHF filters. The large number of users of these systems makes that there is a very ...
2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum, 2009
I. INTRODUCTION X-Ray topography is a very sensitive method to image strain fields in crystals. M... more I. INTRODUCTION X-Ray topography is a very sensitive method to image strain fields in crystals. Many contributions using this technique were devoted to image surface acoustic waves (SAW) in devices employing standing waves (most often SAW resonators) or progressive ...
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1997
World Directory of Crystallographers, 1995
World Directory of Crystallographers, 1995
Journal of Applied Physics, 1982
Dislocations in highly perfect quartz crystals have been characterized by correlating experimenta... more Dislocations in highly perfect quartz crystals have been characterized by correlating experimentally observed section patterns with computer simulations. The Burgers vector observed is the shortest translation vector of the quartz lattice. In cases, such as quartz, where the simple geometrical criteria fail, computer simulation methods are a powerful aid in establishing the Burgers vector of dislocations.
Journal of Applied Physics, 1979
Inhomogeneities of spin distribution are sources of magnetostrictive strains. An infinite 90° (11... more Inhomogeneities of spin distribution are sources of magnetostrictive strains. An infinite 90° (110) Bloch wall in iron for instance acts as a small angle (λ100?3.10−5 rad) twin boundary and introduces a brutal rotation of the lattice. Wall junctions create long range inhomogeneous strains (and stresses). These quantities can be analysed in terms of dislocation densities and disclinations, which may be observed experimentally by X-ray (Lang) topography. This is illustrated here for the classical Dijkstra and Martius domain structure.