Chia-chi Sung | National Taiwan University (original) (raw)

Papers by Chia-chi Sung

The Journal of the Acoustical Society of America, 1991

The “d15 ” constant of the piezoceramics was utilized to design shear mode transducers. These she... more The “d15 ” constant of the piezoceramics was utilized to design shear mode transducers. These shear mode transducers were verified to be pure shear stress/strain sensors/actuators both theoretically and numerically (ANSYS). Active torsional vibration control experiments were conducted on various phenolic and pyrex tubes by using the shear mode sensors/actuators. The free and controlled frequency responses as transfer functions were measured and compared to each other. The finite element mode-frequency analysis was performed to evaluate the structural characteristics for the tubes with and without transducers mounted. The dynamic coupling coefficients were derived for shear mode sensors/actuators based on the finite element mode shapes.

IUTAM Bookseries, 2010

In this paper, characteristics of two-track surface acoustic wave (SAW) filters based on Cu elect... more In this paper, characteristics of two-track surface acoustic wave (SAW) filters based on Cu electrode/(100) AlN/diamond structures were analyzed using the finite element method (FEM) and the transmission matrix method. To achieve optimum performance, the Chebyshev window function was used to modify the reflectivity distributions of reflectors. The SAW parameters for weighted reflectors with various electrode thicknesses and different metallization

2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum, 2009

Propagation characteristics of surface acoustic waves (SAWs) in IDT/(100) AlN/diamond structures ... more Propagation characteristics of surface acoustic waves (SAWs) in IDT/(100) AlN/diamond structures are analyzed in this study using the finite element method (FEM). The extracted coupling-of-mode (COM) parameters are employed to calculate the frequency responses of two-track SAW filters using the transmission matrix method. To enhance the sideband suppression, Chebyshev function is adopted to modify the reflectivity distributions of reflectors, which

2009 IEEE International Ultrasonics Symposium, 2009

Zinc oxide (ZnO) films were combined with diamond to be a composite surface acoustic wave (SAW) s... more Zinc oxide (ZnO) films were combined with diamond to be a composite surface acoustic wave (SAW) substrate showing high velocity and high coupling coefficient. In this study, Rayleigh SAW reflection characteristics of Cu or Al electrodes in (100) or (002) ZnO films on (111) diamond structures were analyzed using the finite element method (FEM). The resonance and anti-resonance frequencies obtained using the FEM are used to compute the effective phase velocity, coupling coefficient, and reflectivity of SAWs in IDT/ZnO/diamond structures with optimized films thickness-to-wavelength ratio and different electrode thickness-to-wavelength ratios. The extracted couplingof-mode (COM) parameters are substituted into the transmission matrix method for the design of the dual mode SAW (DMS) filter for wideband code division multiple access (WCDMA) applications. With the optimized films thickness ratio (h F /λ = 0.42) and Cu electrode thickness ratio (h E /λ) of 0.025, Sezawa mode in the IDT/(100) ZnO/(111) diamond structure possesses the phase velocity of 5209 m/s, coupling coefficient of 3.33%, and reflectivity of 0.15. The tailored DMS filter using these COM parameters yields a RF filter operating at 2140 MHz with 3 dB bandwidth of 60 MHz, insertion loss of 1.36 dB, shape factor of 1.27, and sideband suppression of 39.7 dB.

2009 IEEE International Ultrasonics Symposium, 2009

Controlling the methanol concentration is a key factor in improving the efficiency of the direct ... more Controlling the methanol concentration is a key factor in improving the efficiency of the direct methanol fuel cell. In this study, the immersed-type Love mode sensor based on SiO 2 /STcut Y-propagation quartz was fabricated for monitoring the methanol concentration. A temperature controlled measurement system consisting of a spectrum analyzer and an oscillator circuit was employed to characterize the methanol solutions with different weight concentrations at different temperatures. A theoretical prediction of the phase velocity shift for the methanol solutions with different weight concentrations was also performed for comparison. The results of methanol solutions with different weight concentrations at different temperatures show that the amount of the frequency shift is approximately linearly proportional to the weight concentration, and the proportional rate increases as the temperature increases. The concentration resolutions were 1.1876 and 0.2484 %/kHz by weight at 25℃ and 70℃.

IEEE International Frequency Control Symposium, 2009

The surface acoustic waves (SAWs) propagating in interdigital transducer (IDT)/(100) aluminum nit... more The surface acoustic waves (SAWs) propagating in interdigital transducer (IDT)/(100) aluminum nitride (AlN)/diamond possess the greater phase velocity and coupling coefficient than those in IDT/(002) AlN/diamond. In this study, the finite element method (FEM) is employed to calculate SAW characteristics in these two layered structures with different electric interfaces; i.e., IDT/AlN/diamond, AlN/IDT/diamond, IDT/AlN/thin metal film/diamond, and thin metal film /AlN/IDT/diamond.

Wave Motion, 1999

Acoustically active materials (chiral materials) that lack centrosymmetry due to chirality in the... more Acoustically active materials (chiral materials) that lack centrosymmetry due to chirality in their microstructures can be characterized by the constitutive relations and governing equations for noncentrosymmetric, isotropic micropolar materials. Accordingly, two longitudinally, two right circularly and two left circularly polarized transversal elastic waves can propagate in chiral medium. Using appropriate field representations along with prescribed boundary conditions, scattering characteristics at chiral interfaces can be realized. In this paper, reflection and transmission characteristics of chiral slabs bounded by achiral media for longitudinally elastic waves with normal incidence are thoroughly discussed. Through the above investigations we are in a position to design the chiral slab by tailoring the material parameters and determine the number and the locations of approximately vanishing reflection of the chiral slab over frequency ranges of interest. Results obtained can be applied for the design of broadband acoustic impedance transformer and acoustic absorbers.

Smart Materials and Structures, 1997

Piezoceramic controllers modeled by four-point moments are employed to reduce the sound power tra... more Piezoceramic controllers modeled by four-point moments are employed to reduce the sound power transmitted through the clamped plate. The state of the plate is obtained from the accelerometers through the modal filter. The relationship between the structural vibration and the transmitted sound power is then derived to determine the sound potential which is used as the cost function. This completes

The Journal of the Acoustical Society of America, 1997

Journal of Solid State Electrochemistry, 2012

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. Th... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Journal of Power Sources, 2012

Journal of Power Sources, 2012

Journal of Intelligent Material Systems and Structures, 1994

In this article, active control of pure torsional vibrations using piezoelectric shear-type trans... more In this article, active control of pure torsional vibrations using piezoelectric shear-type transducers is discussed. Pure torsional vibrations can be sensed and controlled by incorporating these transducers into tube-type structures. The effects of changing the electrode orientation with respect to the polarization direction of the shear mode transducers is discussed. Two types of shear mode piezoelectric transducers - ring-type with

Japanese Journal of Applied Physics, 2000

A matrix method is employed in this paper for the solution of wave propagation problems in multil... more A matrix method is employed in this paper for the solution of wave propagation problems in multilayered chiral/achiral slabs bound by two semi-infinite achiral media. Reflection and transmission characteristics of the multilayered chiral slab for longitudinally elastic waves with normal incidence are thoroughly discussed. In addition, by using realistic refractive indices, the desired scattering characteristics are inversely obtained by accurately tailoring the constitutive parameters of the multilayered chiral materials. The obtained results will benefit the design of broadband acoustic impedance transformers and acoustic filters for arbitrarily desired transmittance characteristics.

Japanese Journal of Applied Physics, 1999

Reflection and transmission characteristics of layered chiral media bounded by either chiral or a... more Reflection and transmission characteristics of layered chiral media bounded by either chiral or achiral media for normally incident transverse waves are investigated. The elastic field behavior in a chiral medium is readily described using governing equations and constitutive relations for noncentrosymmetric, isotropic micropolar materials. Using appropriate field representations along with prescribed boundary conditions, scattering characteristics at chiral-chiral and achiral-chiral interfaces

Japanese Journal of Applied Physics, 1999

The dynamic response of a clamped rectangular plate subjected to plane wave incidence and piezomo... more The dynamic response of a clamped rectangular plate subjected to plane wave incidence and piezomoment actuation has been derived in our previous research. The result benefits the comparison of acoustic power transmitted through the plate with and without control. The acoustic power is represented in terms of the amplitudes of the structure modal velocities and the velocities of an array

Japanese Journal of Applied Physics, 1997

ABSTRACT

Japanese Journal of Applied Physics, 2005

Unlike the conventional method of obtaining the spatial impulse response (SIR) for a transducer f... more Unlike the conventional method of obtaining the spatial impulse response (SIR) for a transducer from the time domain, we propose a new and computationally efficient approach for calculating the acoustic field for a rectangular focusing array transducer in a transmitting, receiving, or transmitting-receiving (pulse-echo) mode from the frequency domain. The SIR spectrum, corresponding to each single frequency, is derived by

Japanese Journal of Applied Physics, 2005

A numerical approach is presented for efficiently evaluating the pressure fields radiated by a pu... more A numerical approach is presented for efficiently evaluating the pressure fields radiated by a pulsed linear array transducer in the time domain. Instead of using Green's function, a wide-band time pulse, which is composed of two amplitude-modulated cosines multiplied by the difference between two traveling Heaviside step functions is employed to avoid complicated and time-consuming integration in the frequency domain.

International Journal of Hydrogen Energy, 2013

The Journal of the Acoustical Society of America, 1991

The “d15 ” constant of the piezoceramics was utilized to design shear mode transducers. These she... more The “d15 ” constant of the piezoceramics was utilized to design shear mode transducers. These shear mode transducers were verified to be pure shear stress/strain sensors/actuators both theoretically and numerically (ANSYS). Active torsional vibration control experiments were conducted on various phenolic and pyrex tubes by using the shear mode sensors/actuators. The free and controlled frequency responses as transfer functions were measured and compared to each other. The finite element mode-frequency analysis was performed to evaluate the structural characteristics for the tubes with and without transducers mounted. The dynamic coupling coefficients were derived for shear mode sensors/actuators based on the finite element mode shapes.

IUTAM Bookseries, 2010

In this paper, characteristics of two-track surface acoustic wave (SAW) filters based on Cu elect... more In this paper, characteristics of two-track surface acoustic wave (SAW) filters based on Cu electrode/(100) AlN/diamond structures were analyzed using the finite element method (FEM) and the transmission matrix method. To achieve optimum performance, the Chebyshev window function was used to modify the reflectivity distributions of reflectors. The SAW parameters for weighted reflectors with various electrode thicknesses and different metallization

2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum, 2009

Propagation characteristics of surface acoustic waves (SAWs) in IDT/(100) AlN/diamond structures ... more Propagation characteristics of surface acoustic waves (SAWs) in IDT/(100) AlN/diamond structures are analyzed in this study using the finite element method (FEM). The extracted coupling-of-mode (COM) parameters are employed to calculate the frequency responses of two-track SAW filters using the transmission matrix method. To enhance the sideband suppression, Chebyshev function is adopted to modify the reflectivity distributions of reflectors, which

2009 IEEE International Ultrasonics Symposium, 2009

Zinc oxide (ZnO) films were combined with diamond to be a composite surface acoustic wave (SAW) s... more Zinc oxide (ZnO) films were combined with diamond to be a composite surface acoustic wave (SAW) substrate showing high velocity and high coupling coefficient. In this study, Rayleigh SAW reflection characteristics of Cu or Al electrodes in (100) or (002) ZnO films on (111) diamond structures were analyzed using the finite element method (FEM). The resonance and anti-resonance frequencies obtained using the FEM are used to compute the effective phase velocity, coupling coefficient, and reflectivity of SAWs in IDT/ZnO/diamond structures with optimized films thickness-to-wavelength ratio and different electrode thickness-to-wavelength ratios. The extracted couplingof-mode (COM) parameters are substituted into the transmission matrix method for the design of the dual mode SAW (DMS) filter for wideband code division multiple access (WCDMA) applications. With the optimized films thickness ratio (h F /λ = 0.42) and Cu electrode thickness ratio (h E /λ) of 0.025, Sezawa mode in the IDT/(100) ZnO/(111) diamond structure possesses the phase velocity of 5209 m/s, coupling coefficient of 3.33%, and reflectivity of 0.15. The tailored DMS filter using these COM parameters yields a RF filter operating at 2140 MHz with 3 dB bandwidth of 60 MHz, insertion loss of 1.36 dB, shape factor of 1.27, and sideband suppression of 39.7 dB.

2009 IEEE International Ultrasonics Symposium, 2009

Controlling the methanol concentration is a key factor in improving the efficiency of the direct ... more Controlling the methanol concentration is a key factor in improving the efficiency of the direct methanol fuel cell. In this study, the immersed-type Love mode sensor based on SiO 2 /STcut Y-propagation quartz was fabricated for monitoring the methanol concentration. A temperature controlled measurement system consisting of a spectrum analyzer and an oscillator circuit was employed to characterize the methanol solutions with different weight concentrations at different temperatures. A theoretical prediction of the phase velocity shift for the methanol solutions with different weight concentrations was also performed for comparison. The results of methanol solutions with different weight concentrations at different temperatures show that the amount of the frequency shift is approximately linearly proportional to the weight concentration, and the proportional rate increases as the temperature increases. The concentration resolutions were 1.1876 and 0.2484 %/kHz by weight at 25℃ and 70℃.

IEEE International Frequency Control Symposium, 2009

The surface acoustic waves (SAWs) propagating in interdigital transducer (IDT)/(100) aluminum nit... more The surface acoustic waves (SAWs) propagating in interdigital transducer (IDT)/(100) aluminum nitride (AlN)/diamond possess the greater phase velocity and coupling coefficient than those in IDT/(002) AlN/diamond. In this study, the finite element method (FEM) is employed to calculate SAW characteristics in these two layered structures with different electric interfaces; i.e., IDT/AlN/diamond, AlN/IDT/diamond, IDT/AlN/thin metal film/diamond, and thin metal film /AlN/IDT/diamond.

Wave Motion, 1999

Acoustically active materials (chiral materials) that lack centrosymmetry due to chirality in the... more Acoustically active materials (chiral materials) that lack centrosymmetry due to chirality in their microstructures can be characterized by the constitutive relations and governing equations for noncentrosymmetric, isotropic micropolar materials. Accordingly, two longitudinally, two right circularly and two left circularly polarized transversal elastic waves can propagate in chiral medium. Using appropriate field representations along with prescribed boundary conditions, scattering characteristics at chiral interfaces can be realized. In this paper, reflection and transmission characteristics of chiral slabs bounded by achiral media for longitudinally elastic waves with normal incidence are thoroughly discussed. Through the above investigations we are in a position to design the chiral slab by tailoring the material parameters and determine the number and the locations of approximately vanishing reflection of the chiral slab over frequency ranges of interest. Results obtained can be applied for the design of broadband acoustic impedance transformer and acoustic absorbers.

Smart Materials and Structures, 1997

Piezoceramic controllers modeled by four-point moments are employed to reduce the sound power tra... more Piezoceramic controllers modeled by four-point moments are employed to reduce the sound power transmitted through the clamped plate. The state of the plate is obtained from the accelerometers through the modal filter. The relationship between the structural vibration and the transmitted sound power is then derived to determine the sound potential which is used as the cost function. This completes

The Journal of the Acoustical Society of America, 1997

Journal of Solid State Electrochemistry, 2012

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. Th... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Journal of Power Sources, 2012

Journal of Power Sources, 2012

Journal of Intelligent Material Systems and Structures, 1994

In this article, active control of pure torsional vibrations using piezoelectric shear-type trans... more In this article, active control of pure torsional vibrations using piezoelectric shear-type transducers is discussed. Pure torsional vibrations can be sensed and controlled by incorporating these transducers into tube-type structures. The effects of changing the electrode orientation with respect to the polarization direction of the shear mode transducers is discussed. Two types of shear mode piezoelectric transducers - ring-type with

Japanese Journal of Applied Physics, 2000

A matrix method is employed in this paper for the solution of wave propagation problems in multil... more A matrix method is employed in this paper for the solution of wave propagation problems in multilayered chiral/achiral slabs bound by two semi-infinite achiral media. Reflection and transmission characteristics of the multilayered chiral slab for longitudinally elastic waves with normal incidence are thoroughly discussed. In addition, by using realistic refractive indices, the desired scattering characteristics are inversely obtained by accurately tailoring the constitutive parameters of the multilayered chiral materials. The obtained results will benefit the design of broadband acoustic impedance transformers and acoustic filters for arbitrarily desired transmittance characteristics.

Japanese Journal of Applied Physics, 1999

Reflection and transmission characteristics of layered chiral media bounded by either chiral or a... more Reflection and transmission characteristics of layered chiral media bounded by either chiral or achiral media for normally incident transverse waves are investigated. The elastic field behavior in a chiral medium is readily described using governing equations and constitutive relations for noncentrosymmetric, isotropic micropolar materials. Using appropriate field representations along with prescribed boundary conditions, scattering characteristics at chiral-chiral and achiral-chiral interfaces

Japanese Journal of Applied Physics, 1999

The dynamic response of a clamped rectangular plate subjected to plane wave incidence and piezomo... more The dynamic response of a clamped rectangular plate subjected to plane wave incidence and piezomoment actuation has been derived in our previous research. The result benefits the comparison of acoustic power transmitted through the plate with and without control. The acoustic power is represented in terms of the amplitudes of the structure modal velocities and the velocities of an array

Japanese Journal of Applied Physics, 1997

ABSTRACT

Japanese Journal of Applied Physics, 2005

Unlike the conventional method of obtaining the spatial impulse response (SIR) for a transducer f... more Unlike the conventional method of obtaining the spatial impulse response (SIR) for a transducer from the time domain, we propose a new and computationally efficient approach for calculating the acoustic field for a rectangular focusing array transducer in a transmitting, receiving, or transmitting-receiving (pulse-echo) mode from the frequency domain. The SIR spectrum, corresponding to each single frequency, is derived by

Japanese Journal of Applied Physics, 2005

A numerical approach is presented for efficiently evaluating the pressure fields radiated by a pu... more A numerical approach is presented for efficiently evaluating the pressure fields radiated by a pulsed linear array transducer in the time domain. Instead of using Green's function, a wide-band time pulse, which is composed of two amplitude-modulated cosines multiplied by the difference between two traveling Heaviside step functions is employed to avoid complicated and time-consuming integration in the frequency domain.

International Journal of Hydrogen Energy, 2013