Biomedical subjects

Shuyu Lin

Publications and source records attributed to Shuyu Lin.

10 recordsLinked to original sources

PubMed2006

Study on the radial composite piezoelectric ceramic transducer in radial vibration.

A new type of radial composite piezoelectric transducer in radial vibration is developed and analyzed. The radial composite transducer consists of a piezoelectric ceramic thin ring polarized in the thickness direction and a metal thin circular ring. They are connected together and excited to vibrate in the radial direction. The radial vibrations of a piezoelectric ceramic thin ring and a metal thin circular ring are analyzed, respectively. Their radial electro-mechanical equivalent circuits are obtained. Based on the electro-mechanical equivalent circuits and using the boundary conditions between the piezoelectric ceramic thin ring and the metal thin circular ring in the radial direction, the electro-mechanical equivalent circuit of the radial composite piezoelectric transducer is derived out and the resonance frequency equation is obtained. The relationship between the resonance frequency and the geometrical dimensions of the transducer is analyzed. Some radial composite piezoelectric transducers are designed and manufactured. The resonance frequencies and the anti-resonance frequencies, the electro-mechanical equivalent circuit parameters are measured. The effective electro-mechanical coupling coefficient and the mechanical quality factor are calculated. It is illustrated that the measured radial resonance frequencies are in good agreement with the theoretical results from the resonance frequency equation.

Ceramics↗

PubMed2006

Vibration analysis and sound field characteristics of a tubular ultrasonic radiator.

A sort of tubular ultrasonic radiator used in ultrasonic liquid processing is studied. The frequency equation of the tubular radiator is derived, and its radiated sound field in cylindrical reactor is calculated using finite element method and recorded by means of aluminum foil erosion. The results indicate that sound field of tubular ultrasonic radiator in cylindrical reactor appears standing waves along both its radial direction and axial direction, and amplitudes of standing waves decrease gradually along its radial direction, and the numbers of standing waves along its axial direction are equal to the axial wave numbers of tubular radiator. The experimental results are in good agreement with calculated results.

Computer Simulation↗

PubMed2006

Study on the high power air-coupled ultrasonic compound transducer.

The high power air-coupled compound ultrasonic transducer in flexural vibration is studied. The transducer consists of a sandwich longitudinal piezoelectric transducer and a circular thin plate in flexural vibration. The resonance frequency equation and the equivalent circuit of a circular radiator with clamped boundary condition are derived. The resonance frequency equation and the equivalent circuit of the compound transducer are also obtained. The radiated acoustic field of the circular thin plate radiator is analyzed and the directional pattern is calculated. It can be seen that when the vibrational order of the circular thin plate in flexural vibration is increased, the radiated acoustic field becomes complex.

Journal Article↗

PubMed2006

Applications of a polymeric microgel template/ultrasonic degradation method: preparation of poly(sodium acrylate)/La(OH)3 nano-composites.

A polymeric microgel template/ultrasonic degradation method for the preparation of organic-inorganic nano-composites is proposed and successfully used in the preparation of poly(sodium acrylate) (PAANa) and lanthanium hydroxide nano-composites (PAANa/La(OH)(3)). The nano-composites were prepared via three steps. La(NO(3))(3) was trapped within the PAANa microgels first, and then the metal ions within the microgels were hydrolyzed by slow introduction of ammonia. Finally, the composites of the micro-particles were degraded by ultrasonic treatment. The product was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The average diameter of the composites prepared in this way is about 50 nm and the size distribution of them is narrow. TGA analysis shows that the content of La(OH)(3) in the composites is about 20%.

Gels↗

PubMed2006

Study on a new type of radial composite piezoelectric ultrasonic transducers in radial vibration.

In this paper, a new type of radial composite ultrasonic transducers in radial vibration is presented and studied. The radial composite ultrasonic transducer consists of a solid piezoelectric ceramic thin disk and a hollow metal thin, circular ring in radial vibration; and they are connected together in the radial direction. The radial vibrations of a piezoelectric ceramic thin disk and a hollow, metal, thin, circular ring are analyzed, respectively. Their radial electromechanical equivalent circuits are obtained. Based on the electromechanical equivalent circuits and using the boundary conditions between the piezoelectric ceramic thin disk and the hollow, metal, thin ring, the electromechanical equivalent circuit of the radial composite ultrasonic transducer is derived and the resonance frequency equation is obtained. The theoretical results from the resonance frequency equation are in good agreement with the measured radial resonance frequencies, and they also are in a good agreement with the results from the numerical method.

Journal Article↗

PubMed2005

Study on the Langevin piezoelectric ceramic ultrasonic transducer of longitudinal-flexural composite vibrational mode.

In this paper, the Langevin longitudinal-flexural composite mode piezoelectric ultrasonic transducer is studied. This type of transducers consists of slender metal rods and longitudinally polarized piezoelectric ceramic rings. The resonance frequency equations for the longitudinal and flexural vibrations in the transducer are derived. By correcting the length of the metal slender rods, the simultaneous resonance of the longitudinal and flexural vibrations in the transducer is acquired. The experimental results show that the measured resonance frequencies of the transducers are in good agreement with the computed ones, and the measured resonance frequencies of the longitudinal and the flexural vibrations in the composite transducers are also in good agreement with each other.

Journal Article↗

PubMed2005

Study of low-frequency ultrasonic cavitation fields based on spectral analysis technique.

A kind of new spectral analysis method for analyzing ultrasonic cavitation fields is brought forward in this paper. This method extracts the line spectrum and the continuous spectrum from the cavitation noise spectrum respectively, then obtains estimations of the energy intensities of different cavitation components such as the stable cavitation and the transient cavitation through corresponding calculations. The method is also applied to investigate low-frequency ultrasonic cavitation fields and is compared with spectral level analysis method. The results show that this method can provide adequate information on the course of the cavitation process, give the delicate analysis on the transient cavitation and the stable cavitation, and help to gain an insight into the nonlinear process of cavitation fields. Moreover, it also shows that the criterion for characterization of cavitation intensity presented by Frohly through studying the high-frequency ultrasonic fields can be used to evaluate the low-frequency ultrasonic fields.

Journal Article↗

PubMed2004

Preparation of spherical nanostructured poly(methacrylic acid)/PbS composites by a microgel template method.

Spherical poly(methacrylic acid)/PbS (PMAA/PbS) composites with a fishnet-like surface and core-shell structure were prepared by a microgel template method. The composites were prepared in two steps. Pb(Ac)(2) was dissolved in MAA solution before it was polymerized into microgels in an inverse suspension system. In this way, Pb(2+) was trapped within the microgel network. Then, H(2)S was introduced slowly into the system, and the metal ions were deposited within the microgels as PbS. The presence of PbS was confirmed by X-ray diffraction (XRD) and thermogravimetric measurements, and the morphology of the composites was characterized by scanning electron microscopy (SEM). It was found that the surface structure of the microparticles depends largely on the nature of the continuous phase of the system. The microparticles from xylene have a fishnet-like surface structure, and the inner structure and composition of the particles are different from the outer structure and composition. The surface of the particles from cyclohexane, however, appears smoother and denser than the surface of the particles from xylene. The different structure of the particle surfaces from the two systems has been attributed to the differences in template structure.

Journal Article↗

PubMed2004

Piezoelectric ceramic rectangular transducers in flexural vibration.

Based on the equivalent elastic method and coupled vibration theory, an analytic method is presented to study the flexural vibration of rectangular transducers consisting of piezoelectric ceramic thin plates. By introducing a mechanical coupling coefficient, the flexural vibration of the piezoelectric ceramic rectangular thin plate is reduced to two simple, one-dimensional flexural vibrations of narrow piezoelectric ceramic strips. The resonance frequency equations for the piezoelectric ceramic rectangular thin-plate transducers in flexural vibration are derived under the free and simply supported boundary conditions analytically. The relationship between the resonance frequency and the flexural vibrational order, the geometrical shape, and the dimensions of the piezoelectric ceramic rectangular thin-plate transducer is analyzed. It is demonstrated that the one-dimensional vibrational theory for the flexural vibration of a narrow piezoelectric ceramic strip and the stripe-mode flexural vibrational theory for the piezoelectric ceramic rectangular thin plate can be derived directly from the theory obtained in this paper. Experimental results show that the measured resonance frequencies of the piezoelectric ceramic rectangular thin-plate transducers in flexural vibration under free-boundary conditions are in good agreement with the calculated results. The method presented in this paper can be used in the resonance frequency analysis of vibrating systems in coupled vibration.

Journal Article↗

PubMed2004

Effect of electric load impedances on the performance of sandwich piezoelectric transducers.

Based on the electromechanical equivalent circuit, the sandwich piezoelectric transducer with adjustable resonance frequency is studied. The underlying theory of frequency adjustment is its piezoelectric effect. In this paper, the influence of electric load impedance (including electric resistance, electric inductance, and electric capacitance) on the resonance frequency, the antiresonance frequency, and the effective electromechanical coupling coefficient is analyzed theoretically and experimentally. It is demonstrated that the electric load impedance can change the resonance frequency, the antiresonance frequency, and the effective electromechanical coupling coefficient. When the electric load resistance is increased, the resonance frequency and the antiresonance frequency are increased; the effective electromechanical coupling coefficient has a maximum value when the electric load resistance changes. When the electric load resistance becomes large, the effect of the electric load resistance on the effective electromechanical coupling coefficient is negligible. When the electric load inductance is increased, the resonance frequency and the antiresonance frequency are decreased, whereas the effective electromechanical coupling coefficient is increased. When the electric load capacitance is increased, the resonance frequency, the antiresonance frequency, and the effective electromechanical coupling coefficient are all decreased. It should be noted that when the electric load impedance becomes large, the effect of the electric load impedance on the resonance frequency, the antiresonance frequency, and the effective electromechanical coupling coefficient of a sandwich piezoelectric transducer becomes negligible.

Journal Article↗