bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum Chemical Study on Chemical Vapor Deposition Source Molecules for the Deposition of (Ba,Sr)TiO3 Films: Infrared Band Identifications by Density Functional Calculations
Authors: Nakamura Toshihiro , Tachibana Kunihide
Published: October 2002

The vibrational spectra of the chemical vapor deposition (CVD) source molecules used for the deposition of (Ba,Sr)TiO3 films were investigated by density functional theory (DFT) calculations. On the basis of the DFT calculations, we revised a part of the traditional assignments of the infrared spectral peaks. The spectral peaks of Ti(t-BuO)2(DPM)2 at 627 cm-1 and 578 cm-1 were found to correspond to the Ti–O vibrations in the β-diketone chelate rings and in the alkoxy groups, respectively. These new assignments made it possible to elucidate the difference in the reactivity between the β-diketone chelate rings and the alkoxy groups of the Ti source molecules such as Ti(t-BuO)2(DPM)2. In addition to the Ti source molecules, we demonstrated that the DFT calculation was applicable for the analysis of the vibrational spectra of Ba and Sr source molecules, Ba(DPM)2 and Sr(DPM)2.
Effective Secondary Electron Yield of a Cathode for Plasma Display Panel
Authors: Yukio Murakami Yukio Murakami , Hideomi Matsuzaki Hideomi Matsuzaki , Hiroshi Murakami Hiroshi Murakami , Nobuaki Ikuta Nobuaki Ikuta
Published: October 2002

In order to improve the discharge characteristics of a plasma display panel (PDP), the availability γ′/γ of the secondary electrons from the PDP cathodes is investigated, which is determined by the back-diffusion effect in the discharge gas. We carried out a Monte-Carlo simulation (MCS) under conditions which were varied: the gas composition, the initial energy distribution of emitted electrons due to ions and metastable atoms incident on the metal or insulator cathode, and the electron reflectivity at the cathode. The calculated values of γ′/γ are 0.1–0.95 for ions and metastable atoms under the typical operational condition of the AC- and DC-type PDPs. It is found that the low-energy electrons emitted by Xe ions and metastable atoms have considerable availability even from low reduced electric field E/p. The data obtained in this work may be useful for the discharge simulation and the design of PDP.
Separation of Townsend Secondary Electron Emission Coefficients by Frequency Response Analysis
Authors: Tsurugida Kanji , Otsubo Masahisa , Honda Chikahisa , Ikuta Nobuaki
Published: October 2002

A procedure to separate the Townsend secondary electron emission coefficient γT into three components γTi, γTp and γTm due to ions, photons and metastables, respectively, is presented. The amplification system of ionization current in the form of a positive feedback amplifier with three feedback paths is analyzed in the frequency domain with the system functions given as the Fourier transform of the dynamic properties in the respective paths. The system functions in the three paths change values in different frequency ranges, and thus the three components are separated clearly. As a result of preliminary measurement electrode current in Ar, the separated values of γTi, γTp and γTm are presented and elucidated.
Characterization of Plasma Production by m=0 Standing Helicon Waves
Authors: Nisoa Mudtorlep , Sakawa Youichi , Shoji Tatsuo
Published: October 2002

Excitation of m=0 standing helicon waves (SHWs) of N=1 and 3 modes (m is the azimuthal mode number and N is the number of half-wavelengths in the axial direction) and production of high-density plasmas of the order of n
p≃1013 cm3 have been investigated in a short cylindrical plasma column of 10 cm length [M. Nisoa, Y. Sakawa and T. Shoji: Jpn. J. Appl. Phys. 38 (1999) L777]. Excitation of different N modes of SHWs has caused an abrupt density jump with rf power P
rf and axial static magnetic field B
0. The power-balance equation is solved using the n
p dependence of plasma loading resistance R obtained numerically from a two-dimensional wave code. Calculated P
rf and B
0 dependence of stable n
p agrees well with measured ones. Measured hollow (parabolic) n
p profile caused by the excitation of N=1 (N=3, 5 and travelling helicon wave) mode is explained in terms of the perpendicular (parallel) component of wave electric field E
⊥ (E

z
). Power absorption due to E
⊥ and E

z
is dominant for the hollow and parabolic n
p profiles, respectively.
Measurement of Atomic Incorporation Rates and Modeling of Surface Reactions in (Ba, Sr)TiO3 Films Prepared by a Liquid Source Chemical Vapor Deposition
Authors: Yamamuka Mikio , Kawahara Takaaki , Tarutani Masayoshi , Horikawa Tsuyoshi , Shibano Teruo , Oomori Tatsuo
Published: October 2002

Atomic incorporation rates in (Ba, Sr)TiO3 [BST] films prepared by a liquid source chemical vapor deposition (CVD) method were measured using an X-ray fluorescence (XRF) method for several source supply ratios with different substrate temperatures (T
s) of 420–520°C. The atomic incorporation rates of Ba, Sr, and Ti increased with increasing incident flux of each source material, and subsequently the values became saturated. The activation energies E
a for the incorporated reactions were estimated using the Arrhenius plots of the saturated values. The E
a values were almost the same for Ba, Sr, and Ti, and were about 1.5 eV. The values were almost independent of the source supply ratios. From these experiments, we assumed a CVD model, where the precursors were transported onto the film surface and adsorbed there with their own sticking coefficients. In the model, the sticking coefficients of the Ba and Sr precursors (βBa and βSr, respectively) were effected by the species of precursors adsorbed thereon. The values of βBa and βSr estimated from the experiments were about 1.0×10-4 on the surface adsorbing Ti precursors, while they were about 1.0×10-3 on the other surfaces, i.e., surfaces excluding those adsorbing Ti precursors. The atomic incorporation rates of Ba, Sr, and Ti were numerically simulated, and were in good agreement with the experimental results for several source supply ratios with different T
s values of 420–520°C.
Monte Carlo Simulation Study of Backscattered Electron Imaging in a Chemical Vapor Deposition Scanning Electron Microscope
Authors: Yoshida Takeshi , Nishikata Kentaro , Nagatomi Takaharu , Kimura Yoshihide , Takai Yoshizo
Published: October 2002

A new MC simulation code has been formulated to describe backscattered electron imaging in a chemical vapor deposition scanning electron microscope (CVD-SEM), which we have recently developed for in-situ observation of nucleation and crystal growth of CVD diamond films. This simulation enables us to elucidate the basic mechanism of contrast formation and spatial resolution of the backscattered electron image (BEI) of a diamond film which is synthesized by a microwave plasma in the CVD-SEM. The result has accurately described the experiment, providing intimate insight into BEI-formation; those electrons that are backscattered to the detector by direct collision with gas molecules do contribute to the increase of the background, attaining ∼10% of the total intensity detected at high gas pressure. The present MC simulation program is also applied for determining the optimum setup for in-situ observation of diamond film growth under CVD-SEM.
Improvement in the Sample Mass-Change-Method used for Determination of the Bulk Etch Rate of CR-39 Neutron Detector
Authors: Tahiri Matiullah , Subhani M. S. , Kudo Katsuhisa
Published: October 2002

The bulk etch rate is an important parameter of any etch-track detector. An accurate measurement of the bulk etch rate is, therefore, highly desirable in the calibration of a CR-39-based neutron dosimeter. Amongst several available bulk etch rate measuring techniques, the sample mass change technique is claimed to be the most accurate one. We carried out systematic experiments and found that even this method has some limitations. The problems associated with this method are discussed. To circumvent these problems, modifications in the sample mass change technique have been suggested.
Numerical Investigations of Transmission and Waveguide Properties of Sonic Crystals by Finite-Difference Time-Domain Method
Authors: Toyokatsu Miyashita Toyokatsu Miyashita , Chiryu Inoue Chiryu Inoue
Published: October 2002

The novel properties of a “sonic crystal” are investigated and its application to a new acoustic waveguide are discussed by developing the finite-difference time-domain (FDTD) method for acoustic wave propagation in a finite-size periodic structure. A sonic crystal is formally an acoustic version of a “photonic crystal.” It is not an actual crystal but an artificial one composed of a periodic array of acoustic scatterers imbedded in the host material, and expected to have acoustical band gaps where the acoustic wave cannot penetrate the crystal. These properties are numerically investigated, and sonic crystals are shown not to be acoustic replicas of photonic crystals. Interesting artificial crystals which can be realizable as sonic crystals but not as photonic crystals are realized by clarifying the correspondence relationship between the transverse-electric and transverse-magnetic waves and the longitudinal acoustic wave in the two-dimensional space. Full band-gap characteristics versus wavelength and wave propagation in acoustic waveguides are shown.
Frequency Dependence of Free Radical Formation by Ultrasound in the Presence of Different Rare Gases
Authors: Fukuda Shigekazu , Ogawa Ryohei , Kondo Takashi
Published: October 2002

The frequency dependence of the hydroxyl radical yield produced by 47 kHz and 400 kHz ultrasound in the presence of rare gases was studied by electron paramagnetic resonance-spin trapping. 5,5-Dimethyl-1-pyrroline-N-oxide was used to detect hydroxyl radicals. Here, we show that the amount of hydroxyl radical yield produced by 400 kHz ultrasound was less inversely proportional to the thermal conductivity than those induced by 47 kHz ultrasound.
Computer Experiments on Solitons in Three-Dimensional Crystals with Nearest-Neighbor and Next-Nearest-Neighbor Atomic Interactions
Authors: Joarder Md. Mahbubul Alam , Minato Atsushi , Ozawa Satoru , Hiki Yosio
Published: October 2002

Molecular dynamics simulation was performed for three-dimensional (3D) cubic mass-spring model crystals. Anharmonic potential up to the fourth order was taken into account, and central forces between the nearest neighbor (nn) and the next nearest neighbor (nnn) atoms were considered. The ratio of the potential between the nnn atoms to the potential between the nn atoms was varied. An input pulse displacement was given to central atomic planes in the crystal or to the end atomic plane of the crystal, and induced displacements and velocities of all atoms were computed. As the nnn interaction was enhanced, the soliton velocity increased and the soliton energy decreased. The results were compared with those of 1D and 2D crystals obtained previously. The increase of soliton velocity due to the enhanced nnn interaction was largest for 1D crystals, and the decrease of soliton energy was smallest for 2D crystals. Discussions and remarks were presented for these results.
Effects of Tensile Stress on the Hypersonic Properties of Thin Polymer Films
Authors: Yoshida Mikio , Hisa Kenzo , Matsukawa Mami , Otani Takahiko , Ohtori Norikazu
Published: October 2002

The effect of tensile stress on the hypersonic wave velocities of polymer films was investigated using a Brillouin scattering method. From the real-time measurements during the tensile test, an interesting behavior of the longitudinal wave velocity has been observed. By comparing the velocity profile with the stress-strain curve, velocity changes indicate that the small scale deformation of the film propagates from the edge to the center and gradually spreads. These results point out the possibility of the Brillouin scattering method as a useful tool for nondestructive and real-time measurement of the stress and deformation in the sample.
Ultrasonic Study on Sintered Magnetite across the Temperature Region from 78 K to 300 K
Authors: Kashiwagura Nobuo , Sakai Shiun , Kamioka Hiroaki
Published: October 2002

Compressional and shear wave velocities and attenuation in sintered magnetite were accurately measured to investigate the Verwey transition by the pulse transmission method using a dual acoustic path across the temperature range between 78 K and 300 K. The temperature dependence of the compressional and shear wave velocities of the sintered magnetite exhibited a steep depression at ∼ 90 K. The low transition temperature suggests nonstoichiometry of the present sintered sample. Using the measured ultrasonic data, the elastic properties of sintered magnetite are discussed.
Effect of Carbonic Anhydrase II in Molten Globule State on Physical Properties of Dimyristoylphosphatidylcholine Liposome
Authors: Sakai Hiroko , Tanaka Michiko , Imai Kenichiro , Sonoyama Masashi , Mitaku Shigeki
Published: October 2002

Ultrasonic relaxation measurement was employed for confirmation of the interaction between dimyristoylphosphatidylcholine (DMPC) membrane and a soluble protein, carbonic anhydrase II (CA II). The enhancement of the fluctuation of DMPC membrane structure was observed in the presence of CA II under acidic condition, pH 3.6–4, indicating the interaction between DMPC and CA II. The pyrene fluorescence spectrum of CA II solution clearly showed that this protein adopted an unfolding intermediate called the molten globule state under the low pH condition, in which CA II interacted with DMPC. However, CA II in the molten globule state did not cause membrane lysis in contrast to the high lytic activity of α-lactalbumin on DMPC liposomes.
Measurement of the Ferroelectric Domain Distributions Using Nonlinear Dielectric Response and Piezoelectric Response
Authors: Kaori Matsuura Kaori Matsuura , Yasuo Cho Yasuo Cho , Hiroyuki Odagawa Hiroyuki Odagawa
Published: October 2002

Scanning nonlinear dielectric microscopy (SNDM) is the first successful purely electrical method for observing the ferroelectric domain distributions. At present its resolution is of the sub-nanometer order. As another method for measuring the ferroelectric domains, the piezoelectric response imaging method is often used. In this study, we compare the resolution of SNDM with that of piezoelectric response imaging and confirm that SNDM gives a much higher resolution than that obtained by piezoelectric imaging. A fundamental study to apply the SNDM system to the ferroelectric reading and writing system is also performed.
Characterization of Homogeneity of Langasite Wafers Using Bulk-Wave Measurement
Authors: Wang Shou-Qi , Uda Satoshi
Published: October 2002

A characterization technique for homogeneity of piezoelectric wafers utilizing bulk-wave measurement was established, and measurements were carried out on langasite (LGS: La3Ga5SiO14) wafers fabricated in our laboratory. The technique is capable of predicting the homogeneity of the phase velocity of a surface acoustic wave (SAW), which determines the deviation of the central frequencies of SAW devices, by measuring the distribution of the frequency constant of thickness-shear mode resonance. The frequency constant, measured by a combination of resonance frequency measurement and thickness measurement in a single wafer, yields a relative accuracy of about ±55 ppm. The distribution of the frequency constant is consistent with that of the phase velocity of SAW obtained by fabricating and measuring SAW devices. The method is both rapid and nondestructive, thus is suitable for routine characterization in the production of piezoelectric wafers. Characterization of langasite wafers using this technique correlated inhomogeneity to the growth conditions of the crystal.
Mechanical Quality Factor of Multilayer Piezoelectric Ceramic Transducers
Authors: Sasaki Yasuhiro , Takahashi Sadayuki , Yamamoto Mitsuru
Published: October 2002

It has long been known that the mechanical quality factor at resonance for multilayer piezoelectric transducers decreases as the number of ceramic layers is increased. We investigated this phenomenon using multilayer transducers, which are driven in a longitudinal mode of the piezoelectric transverse-effect. In this report, we express equivalent circuits for the transducers with resistance for electrode layers. We concluded that the mechanical quality factor at resonance for the transducers decreases because the ratio of resistance for electrode layers to the total equivalent resistance increases with the number of ceramic layers.
Development of a New System for Measuring Skull Bone Thickness by the Pulse Compression Method
Authors: Hatakeyama Rokuro , Yoshizawa Masasumi , Moriya Tadashi , Yagi Shin-ichi
Published: October 2002

Precise correction for γ ray attenuation in the skull bone is essential when obtaining quantitative single-photon emission computed tomography (SPECT) images of the brain. Correction for γ ray attenuation is approximately proportional to the density and thickness of the bone under investigation. Therefore, if the acoustic impedance and speed of sound in the bone are measurable using ultrasonic techniques, then the density and thickness of the bone sample can be calculated. We propose a method for determining simultaneously the thickness of and speed of sound in the skull bone through in vivo measurements; the principle being that the time delay between two discrete transmission paths will yield the desired information. Thus, it is necessary to distinguish between the responses of these two transmission paths. The proposed method incorporates the pulse compression method to measure the time delay between detected transmission paths and reduce dispersion in the transmission line, thus increasing the signal-to-noise (S/N) ratio and significantly improving measurement accuracy. Using the proposed pulse compression method, the speed of sound in a number of materials was obtained, with the following results: 5 mm-thick poly methyl methacrylate(PMMA) plate, 2620±130 m/s; compact bone, 3820±250 m/s; spongy bone, 1930±90 m/s. The errors in thickness indicated by these measurements were 5.6%, 7.2% and 12% for the PMMA plate, compact bone and spongy bone, respectively. Thus, using a thin transmission line, the proposed method makes it possible to determine the thickness of a bone sample with sufficient accuracy. It is anticipated that this method, which is based on ultrasonic measurements, will be useful for application in brain SPECT.
Application of Time Slice to an Imaging System Using Acoustic Holography
Authors: Michitoshi Noguchi Michitoshi Noguchi , Koichi Mizutani Koichi Mizutani , Keinosuke Nagai Keinosuke Nagai , Wen Cao Wen Cao
Published: October 2002

Acoustic holography has attained a high lateral resolution but a poor axial resolution. In this study, to achieve the high axial resolution, time slice is applied to an imaging system using acoustic holography. The time slice can select the reflected signals from objects at different distances. In this method, the sampling interval of detected signal decides the axial resolution, and the aperture of the transducer decides the lateral resolution. The result of a simulation shows good axial and lateral resolutions. The method uses only one specified frequency which matches with narrow-band transducers.
Simple Ultrasonic Measurement of Concentration in Solutions with Temperature Compensation by a Phase Difference Method
Authors: Kiyoshi Ikeda Kiyoshi Ikeda
Published: October 2002

In this paper, we propose a new simple ultrasonic technique for measuring the concentration of solutions by a phase difference method with temperature compensation. This technique relies on sound velocity changes due to variations in solution concentration. An empirical equation of the sound velocity for both the sugar and NaCl solutions, which covered a concentration range of 0.0–20.0% and a temperature range of 15–45°C, was obtained by analyzing the measurements of various sound velocities through the least squares method. It became evident that a similar temperature-compensation factor can be used for both the solutions in terms of dependence on temperature in their equations. An empirical equation was applied to design a temperature compensation circuit. The measuring system with temperature compensation was shown to yield a 0.01% accuracy of concentration determination, independent of the temperature variation of ±0.9°C around 25.2°C for the sugar solution and of ±1.0°C around 25.4°C for the NaCl solution.
Spectroscopy for High Atomic Energy Levels Using External Cavity Laser Diode
Authors: Oba Masaki , Wakaida Ikuo , Miyabe Masabumi
Published: October 2002

The fine structure intervals and isotope shift of the high 32D levels of atomic lithium were measured by two-step excitation fluorescence spectroscopy using an external cavity laser diode for the first-step excitation, using various scanning ranges over the first-step transition structure. Second-step spectra of the specific isotope pairs and fine components were readily assigned to the corresponding transitions.
Brillouin Measurement of Glass-Forming Ethanol Using an Angular Dispersion-Type Fabry-Perot Interferometer
Authors: Jae-Hyeon Ko Jae-Hyeon Ko , Zhai Chao Zhai Chao , Shin-ichi Itoh Shin-ichi Itoh , Seiji Kojima Seiji Kojima
Published: October 2002

An angular dispersion-type Fabry-Perot interferometer is a powerful tool for measuring the Brillouin spectra of glass-forming materials, particularly of low-molecular-weight molecules which require a high cooling rate to avoid crystallization. A solid-state etalon, a highly sensitive charge-coupled-device (CCD) detector and a small-aperture iris were used to obtain a high finesse above 100. The Brillouin spectra of ethanol were measured using a Brillouin system in the temperature range from 350 K to 220 K. Relaxation times obtained from the analysis using a simple viscoelastic theory shows an Arrhenius behavior with an activation energy of 2.7 kcal/mol and a pre-exponential factor of 5.8×10-14 s in the high-temperature range above 220 K, which is consistent with the newly observed β process by dielectric spectroscopy [R. Brand et al.., Phys. Rev. B 62 (2000) 8878].
Finite Element Simulation of Nonlinear Acoustic Behavior at Minute Cracks Using Singular Element
Authors: Okada Jyun-ichi , Ito Toshihiro , Kawashima Koichiro , Nishimura Naoya
Published: October 2002

A finite element method (FEM) simulation of wave propagation is performed for a model plate which includes minute cracks nucleated by spallation. The minute cracks are modeled by singular elements which express nonlinear stress-strain at the crack surfaces. The transmitted wave through these cracks is simulated and the 2nd harmonic amplitude is processed by fast fourier transform (FFT). The ratio of the 2nd harmonic component to the fundamental one increases with an increase in the incident wave of amplitude for the incident wave of amplitude 5–20 nm. The simulated results qualitatively confirm the measured nonlinear acoustic response on spalled samples.
Measurements of Multimode Leaky Lamb Waves Propagating in Metal Sheets
Authors: Lee Yung-Chun
Published: October 2002

In this paper, we present an experimental method for determining complicated dispersion relation of multiple modes of leaky Lamb waves propagating in a plate. The measurement system is based on a focused polyvinylidene fluoride (PVDF) transducer and its defocusing measurement method. A standard waveform processing procedure is developed to analyze the measured acoustic waveforms. With a new image representation method, the dispersion relation of the leaky Lamb wave is displayed as a gray-scale image. Multiple dispersion curves of leaky Lamb waves can be easily identified in the image and then quantitatively determined. Metal sheets of 0.2 to 0.5 mm in thickness are experimentally tested by this technique. Up to eight modes of leaky Lamb waves in the frequency range of 4 to 20 MHz are simultaneously excited and detected. The dispersion curves are accurately determined.
Photothermal Deflection Microscope Using Linear-Motor-Driven Pulse Stages and its Applications
Authors: Hoshimiya Tsutomu , Miyamoto Katsuhiko
Published: October 2002

A photothermal deflection microscope using linear-motor-driven slide stages for scanning was designed and fabricated. The photothermal microscope achieved high-resolution scanning (0.1 µm step), fast scanning (40 mm/s) and random access. It operates in a conventional operating software environment as a photoacoustic microscope and is capable of operating in an open-air environment. It was applied to the imaging of semiconductor microdevices such as integrated circuits. Resolution up to 8–12 µm was achieved.
Generation and Detection of 400-MHz-Band Surface Acoustic Waves Using the Phase Velocity Scanning Method
Authors: Cho Hideo , Tsukahara Yusuke , Yamanaka Kazushi
Published: October 2002

We succeeded in generating and detecting high-frequency surface acoustic waves (SAWs) up to 400 MHz by improving an apparatus for the scanning interference fringes (SIF) approach of the phase velocity scanning method using an optical knife-edge technique with a single lens. Using the new SIF apparatus, we confirmed that we are able to measure the SAW velocity anisotropy of a single-crystal Si(001) wafer within 0.1% relative error. We also measured the velocity anisotropy of Sezawa waves on a Si(001) wafer with a 1430-nm-thick Cu film and estimated Young's modulus and thickness of the Cu film by an inverse analysis. The estimated Young's modulus was close to that of bulk Cu (129.8 GPa). On a single-crystal Si(001) wafer with thinner Cu films (270–700 nm), we measured the SAW velocity along the [110] direction of the Si substrate by the time-of-flight method. The measured velocities decreased with increasing film thickness. The measured velocity for the thicker sample approximated the group velocity calculated from the estimated value for 1430-nm-thick Cu film by the inverse analysis.
Evaluation of ZnO Varistors by Photoacoustic Spectroscopy
Authors: Yasuhiro Ohbuchi Yasuhiro Ohbuchi , Akitsugu Kimura Akitsugu Kimura , Toshio Kawahara Toshio Kawahara , Jun Morimoto Jun Morimoto , Taro Toyoda Taro Toyoda
Published: October 2002

ZnO varistors degraded under various conditions were evaluated by photoacoustic spectroscopy (PAS). The degradation where the grain boundary is damaged by DC bias stress is more than that by AC bias stress. PAS, however, reveals that the interior of the grains of the sample degraded by AC bias stress is much more damaged than that by the DC bias stress. The PA signal intensity at a wavelength of more than 500 nm increases and the dispersion of the spectrum decreases throughout the wide wavelength range considered with the degradation time. In particular, the decrease of the spectral dispersion below 500 nm is caused by the change of the electronic states at the interface, that is, the increase of the recombination center of the space charge. The annealing effect on the degradation of ZnO varistors was also studied. The PA spectrum of the sample annealed in N2 gas corresponds to those of the sample degraded by DC and AC bias stress for a long time. This suggests that the degradation of ZnO varistors is closely related to the release of oxygen from both ZnO grain interior and grain boundaries.
Optical Measurement of Sound Fields Information Using Mach-Zehnder Interferometer
Authors: Koichi Mizutani Koichi Mizutani , Tomohiro Ezure Tomohiro Ezure , Keinosuke Nagai Keinosuke Nagai , Masahiro Yoshioka Masahiro Yoshioka
Published: October 2002

An optical method for measuring information of sound fields using the Mach-Zehnder interferometer is described. The Mach-Zehnder interferometer is advantageous for obtaining quantitative measurements of phase values in comparison to other visualization methods. In this study, we simultaneously investigate a two-dimensional data acquisition system for the projection image of an optical phase deviation in proportion to sound fields below the frequency of 2.16 MHz. In the experiment, the charge-coupled device (CCD) camera is used as a function of a mean value detector. The experimental results of the optical phase deviation along the ultrasound axis are useful as primary data for estimating the sound pressure. The two-dimensional measurement system using a CCD camera proposed in this paper has the advantages of acquiring the data in a short time when used in an environment where the measurement conditions change.
Surface Acoustic Waves on a Sphere –Analysis of Propagation Using Laser Ultrasonics–
Authors: Ishikawa Satoru , Cho Hideo , Yamanaka Kazushi , Nakaso Noritaka , Tsukahara Yusuke
Published: October 2002

Using the laser ultrasonic method, we investigated the distribution of surface acoustic waves (SAWs) on a sphere excited by a line source. Experimental results revealed that the SAWs were confined within a narrow path due to the balance of the diffraction and convergence effects. Moreover, the distribution had unique divergent, collimating and focussing forms, which had been predicted theoretically. These results were generally in good agreement with the results calculated using the approximate Green's function. It was shown that the distribution of SAWs is well defined by the half-aperture angle of the source and by the product of the wavenumber and the radius of the sphere.
Vibration Analysis of Thickness-Shear-Mode Trapped-Energy Resonators Excited by Parallel Electric Field
Authors: Ishikawa Toshihiro , Abe Hiroshi , Watanabe Hiroshi
Published: October 2002

The energy trapping of thickness-shear vibrations that are excited by parallel electric field in a partially polarized piezoelectric-ceramic plate is analyzed by the finite element method (FEM), and characteristics of the thickness-shear-mode trapped-energy resonators for vibratory gyroscopes are theoretically revealed. The calculated results obtained by FEM agree well with the measured results with respect to the displacement and vibration energy distributions. It is shown from the results that the vibrational energy of trapped-energy modes is almost confined to the central region of a partially polarized piezoelectric-ceramic plate and the displacement distribution of the mode can be varied by adjusting electrode dimensions.
Ultrasonic Focusing Gaussian Source to Receive Nonlinearly Generated Second Harmonic Sound by Itself
Authors: Saito Shigemi , Kameyama Yoshinori , Nakamura Kiyoshi
Published: October 2002

A focusing source to concurrently detect the nonlinearly generated second harmonic sound contained in the reflected wave has been produced. A 36° rotated Y-cut LiNbO3 plate of 20 MHz fundamental resonance frequency with a reversed polarization layer formed by heat treatment is bonded to a plane surface of a solid acoustic lens whose thickness is set at a small value so as to avoid the influences of nonlinear distortion and multiple reflection within the lens. One of the electrodes on the piezoelectric plate is fabricated to a 20-point-star shape. The formation of a 20 MHz focused Gaussian beam and the capability of receiving the 40 MHz second harmonic sound are confirmed through experiments.
Suppression of Inharmonic Modes Using Elliptical Periphery Electrodes in Very High Frequency Fundamental AT-Cut Resonators
Authors: Iwata Hirokazu , Hirama Koichi
Published: October 2002

This paper describes suppression of inharmonic modes in a trapped-energy AT-cut resonator operating in a very high frequency (VHF) fundamental mode. This resonator has an elliptical excitation electrode conforming to the anisotropy in the AT-cut quartz plate. Moreover, the new resonator has a mesa to control the plateback and a second electrode with an elliptical opening to decrease the plateback. Resonators operating at 155 MHz are manufactured. In these resonators, the length of the excitation electrode is 53 times the thickness of the crystal substrate. Nevertheless, all of the inharmonic modes can be suppressed by employing the above electrode structure. The ratio of the impedance at the most strongly excited inharmonic mode to the impedance at the main mode in the new resonator is four times that in a conventional resonator with a rectangular excitation electrode.
An Investigation of Optical Excitation and Detection of Piezoelectric Vibrations
Authors: Satoru Noge Satoru Noge , Mie Kurita Mie Kurita , Takehiko Uno Takehiko Uno
Published: October 2002

We have previously proposed a piezoelectric sensor configuration determined using an optical-access method and reported the simulation results. Two issues have to be resolved for fabricating such a sensor; one is to develop a suitable optical-to-electrical conversion technique, and the other is to develop an optical measurement method for piezoelectric resonance. We examined the use of a Schottky-barrier photodiode (SBPD) for photoelectric conversion to excite piezoelectric vibration in the very high frequency (VHF) region. We found that the photoelectric output of SBPD corresponds to the intensity of the modulated light. The excitation power of piezoelectric vibration is between 10 µW (at 70 MHz) and 32 µW (at 50 MHz). However, optical detection of piezoelectric vibration is difficult. In this paper, we propose a waveguide-type light circuit using a pair of Y-branch elements based on the Mach-Zender interferometer. An analysis on the sensitivity of the circuit for vibration detection was carried out and relatively higher sensitivity was predicted. Furthermore, the photoelastic constant p
66
′ for AT-cut quartz was measured.
A New Tactile Sensor Using the Edge Mode in a Piezoelectric-Ceramic Bar
Authors: Watanabe Hiroshi
Published: October 2002

The edge mode, whose vibrational energy is confined to the edge region of a piezoelectric-ceramic bar, is analyzed by the finite element method (FEM) and characteristics of the mode are clarified. A new tactile sensor using the edge mode in a piezoelectric-ceramic bar is proposed and its experimental results are presented. The results show that piezoelectric tactile sensors with very high sensitibity and supporting ease can be realized by the use of the edge mode.
Model for a Quartz-Crystal Tuning Fork by Sezawa's Approximation and Winkler's Foundation of the Supporting Elinvar Alloy Wire and Analysis of Its Frequency Change Ratio
Authors: Itoh Hideaki
Published: October 2002

We developed a method for analyzing the effect of a supporting wire on the frequency of a quartz-crystal tuning fork independent of the finite element method (FEM). In order to estimate the influence of the supporting wire of the tuning fork, we approximated the right half of the tuning fork as an L-shaped bar in which the bars at both the base and the arm undergo bending vibration. Furthermore, we approximated the supporting wire as an elastic foundation with a spring constant K. A comparison was made between frequency changes calculated by this method and those calculated by FEM, and the influences of spring constant K and the length of the supporting wire on the frequency change calculated by this method are discussed.
Simultaneous Detection of Density and Viscosity Using Surface Acoustic Wave Liquid-Phase Sensors
Authors: Jun Kondoh Jun Kondoh , Shinich Hayashi Shinich Hayashi , Showko Shiokawa Showko Shiokawa
Published: October 2002

A shear horizontal surface acoustic wave (SH–SAW) can function as a liquid-phase sensor. In this paper, we describe the simultaneous measurement methods for liquid density and viscosity. For this purpose, a textured (or sagittally corrugated) propagation surface is designed to trap the liquid in dented structures. Although a smooth surface is affected by the density and viscosity products, the textured surface is influenced by both the density and viscosity products, and also the density due to trapping of liquid in the dented structures. Therefore, by detecting the differential signals between the textured and the smooth surfaces we can determine the liquid density and viscosity separately.
Research of Super-High Electromechanical Coupling Surface Acoustic Wave Substrates
Authors: Yamanouchi Kazuhiko , Odagawa Hiroyuki
Published: October 2002

The properties of surface acoustic wave (SAW) devices mainly depend on the choice of piezoelectric substrate materials. The important properties required for SAW substrates are a large electromechanical coupling coefficient (k
2), small temperature coefficient of delay (TCD), and low propagation loss, etc. Especially, super-high coupling substrates are very important for obtaining wide-band SAW filters, wide-band voltage controll oscilater (VCO) and delay lines with small insertion loss. KNbO3 single crystal has an extremely large electromechanical coupling coefficient (k
2=53%) and zero TCD at approximately room temperature. Large-scale single-crystal growth technologies are now under investigation. In this study, the propagation characteristics of SAW in PZNT and KTP substrates are investigated experimentally in order to obtain higher coupling substrates than those of KNbO3. The experimental results show that the substrates have large k
2. Also, theoretical SAW propagation characteristics with a k
2 of about 100% are analyzed and their physical phenomena are discussed.
Fabrication of Si/LiNbO3 Structure by Using Film Bonding Process
Authors: Kaneshiro Chinami , Hirai Rieko , Koh Keishin , Hohkawa Kohji
Published: October 2002

In this work, we studied a fabrication process of the surface acoustic wave (SAW)-semiconductor coupled device with a Si/LiNbO3 structure by a film bonding process. The aim of this process is to realize a coupled device with a high performance and mass productivity for cost reduction. In order to realize bonding silicon films on a LiNbO3 substrate, we proposed the process of releasing a Si thin film from a silicon-on-insulator (SOI) wafer and examined the etching conditions of a SiO2 (box) layer. We also tried to apply local heating treatment using a microwave and an infrared laser to enhance the bonding force between the Si film and LiNbO3 substrate, and successfully bonded Si films released from a SOI wafer onto the LiNbO3 substrate. Based on these results, a test device with a Si/LiNbO3 structure was fabricated and the interaction between SAW and the optically induced carrier in the Si film semiconductor was discussed.
Bonding Technology of Semiconductor Film on Piezoelectric Substrate Using Epitaxial Lift-Off Technology
Authors: Keishin Koh Keishin Koh , Kenichiro Miyadai Kenichiro Miyadai , Yusuke Aoki Yusuke Aoki , Chulun Hong Chulun Hong , Satoru Noge Satoru Noge , Chinami Kaneshiro Chinami Kaneshiro , Kohji Hohkawa Kohji Hohkawa
Published: October 2002

In this paper, we report the results of a study on the basic problems of the mass production of epitaxial liftoff (ELO) film bonding technology. We propose a new releasing method for a large number of semiconductor films using polyimide to protect the semiconductor films. We investigated the basic process conditions and successfully released a large number of stripe shaped GaAs films. We also studied the heating method for enhancing the bonding strength between a small-sized semiconductor film and a piezoelectric substrate. We investigated the effect of migration of water molecules from the bonding interfaces using microwave and laser irradiation. We estimated the crystallinity of semiconductor films by X-ray diffraction. The results clarified that these processes were effective in improving mass productivity on the fabrication technology of surface acoustic wave (SAW)-semiconductor coupled devices.
Simulation Study on Semiconductor Coupled Surface Acoustic Wave Convolver through a Multi-Strip Electrodes
Authors: Hohkawa Kohji , Suda Takaya , Aoki Yusuke , Kaneshiro Chinami , Koh Keishin
Published: October 2002

This paper presents results of simulation study on a semiconductor coupled surface acoustic wave (SAW) convolver, in which the propagating SAW on a highly coupling coefficient piezoelectric substrate, couples with a bonded semiconductor diodes through multi-strip electrodes. We focus our study on a relatively wide band device which is the main feature of a highly efficiency device. By using a simple analysis and circuit simulator, based on the simulation program with integrated circuit emphasis (SPICE), we clarified the effect of device parameters, such as the shape of multi-strip tapping electrodes, characteristics of diode, impedance matching condition, kinds of transmission code and electro-mechanical coupling coefficient of SAW, on the device performances. We discussed the phenomenon, which cause the degradation, focusing on the frequency domain. We also clarified the essential problems of second order effect on the wide bandwidth device, which should be solved.
Coefficients of Coupled-Mode Equations for Reversal of Directivity Transducers on a 50°Y-25°X La3Ga5SiO14 Substrate
Authors: Koji Hasegawa Koji Hasegawa , Kiyoshi Inagawa Kiyoshi Inagawa , Masanori Koshiba Masanori Koshiba
Published: October 2002

Computed results of all the coefficients of coupled-mode equations are presented for a transduction center-shift-reversal-of-directivity transducer (TCS-RDT) and an electrode-width-controlled-reversal-of-directivity transducer (EWC-RDT) on a 50°Y-25°X La3Ga5-SiO14 substrate. To the best of our knowledge, an EWC-RDT is being reported for the first time. The aluminum electrode thickness and width dependences of the coefficients are investigated in detail. Numerical results show that we can choose pairs of width and height of the electrodes for a distance of λ/8 with λ being the surface acoustic wave (SAW) wavelength at the center frequency between the reflection center and the transduction one. Our results of the insertion loss for a filter composed of a TCS-RDT and two split-electrode interdigital transducers (IDTs) agree well with those of the earlier experiments.
A High Power Ultrasonic Linear Motor Using a Longitudinal and Bending Hybrid Bolt-Clamped Langevin Type Transducer
Authors: Yun Cheol-Ho , Ishii Takaaki , Nakamura Kentaro , Ueha Sadayuki , Akashi Koji
Published: October 2002

A hybrid transducer type ultrasonic linear motor using the 1st longitudinal and the 2nd bending vibration modes of a bolt-clamped Langevin type transducer has been proposed and studied for accomplishing high mechanical output. The longitudinal vibration generates the mechanical driving force and the bending vibration controls the frictional force. To obtain large vibration amplitude and large mechanical output, a method of tuning the longitudinal resonance frequency to the bending one was investigated using finite element simulations, and demonstrated experimentally. To avoid magnetic interaction, we employed phosphor bronze for the bolt of the transducer. The prototype motor achieved the no-load velocity of 0.47 m/s and the maximum output mechanical force of 92 N.
Search for Objects on the Deep-Sea Floor Using Side Scan Sonar with a Tilted Arrangement Transducer Array
Authors: Naoi Jun , Saito Hideaki , Shimura Takuya , Momma Hiroyasu , Tsuchiya Toshio
Published: October 2002

A deep-sea unmanned vehicle “Kaiko,” which can be used under water to a depth of 11,000 m, is equipped with a side scan sonar newly developed for underwater topographic survey and searching for lost objects. The side scan sonar features a tilted arrangement transducer array for suppressing grating lobes. The driving frequency on the port side is 38 kHz, and that on the starboard side is 42 kHz. The source beam width in the longitudinal direction is 2° and that in the transverse direction is 50°. In 1999, objects lost underwater were located using the side scan sonar, and fallen rocket parts as large as several meters could be found in a range of about 1 km.
Possibility of Metal Processing Using Ultrasonic Cavitation Jet
Authors: Aoyagi Ryoji , Fujiwara Ryuichi , Niita Tokuo
Published: October 2002

Utilizing a high-intensity ultrasonic cavitation, a processing experiment was conducted with the aim of performing volumetric flow adjustment of a fuel jet nozzle to be used for a small engine, which cannot be carried out by a method such as machining. At the bottom of the nozzle used for the experiment, which is in the shape of a cup, a nozzle hole with a diameter of 0.15 mm is drilled. In this experiment, we make adjustments in the volumetric flow by grinding and removing the machining burr with the aid of the processing power of ultrasonic cavitation. The processing effect is highly dependent on the ultrasonic cavitation intensity. In the experiment, the processing reservoir was filled with pressurized highly deaerated water to increase the processing force by allowing cavitation with high intensity to be generated. The processing principle is to utilize the effect of a cavitation jet flow passing through the nozzle hole. To restrain the intake of the bubbles into the flow circuits during the pressure reduction cycle of the vibrator, the water flow was discharged into a pressure reduction reservoir. By allowing the horn tip with a diameter of 6 mm at a frequency of 28 kHz to approach the sample, followed by high-intensity ultrasonic irradiation, powerful cavitation was generated. As a result of the evaluation of the processing efficiency made based on the volumetric flow increase and microscopic observation of the nozzle, burrs smaller than 10 µm were almost entirely removed within 15 min of initial irradiation, resulting in a volumetric flow increase of more than 0.4%/min. However, in the case of burrs of more than 10 µm, no force that could remove the burrs was found. It was surprising for the burrs to generate deformation rather than to be removed.
Study of Atomization of a Water Jet by High-Intensity Aerial Ultrasonic Waves
Authors: Ito Youichi
Published: October 2002

An experimental study has been carried out on the atomization of a water jet by aerially radiating it with high-intensity ultrasonic waves. A sound source that enables the linear generation of high-intensity aerial ultrasonic waves (frequency: approximately 20 kHz) is combined with a cylindrical reflection plate in order to create a standing-wave sound field. An attempt has been made to atomize a water jet of 1 mm diameter by passing it through the above sound field at a velocity of approximately 30 m/s. It has been clarified that nodes of sound pressure in the standing-wave sound field are effective for the atomization of a water jet. In addition, the atomizing phenomenon of a water jet has been observed precisely. The relation between the intensity of sound waves required for atomization and the radiation duration has also been clarified. Even the radiation of sound waves for only 2 ms atomizes water. This suggests that a very fast water jet at 300–500 m/s might be atomized.
Effect of Surface Duct on Pulses Propagating in a Sound Channel in the Ocean
Authors: Kohji Futa Kohji Futa , Keizo Ando Keizo Ando , Toshiaki Kikuchi Toshiaki Kikuchi , Toshio Tsuchiya Toshio Tsuchiya
Published: October 2002

In ocean acoustic tomography, unexpected changes in the travel time of acoustic pulses can sometimes be observed. It is considered that the possible causes are internal waves, layered sound speed microstructures and surface ducts. In this paper, we analyze the effect of a surface duct on a pulse that is propagating in a sound channel in the ocean by using the parabolic equation (PE) method. The received pulses change sensitively when a surface duct exists above the sound source or the receiver that is located around the axis of the sound channel. It has little effect on the pulses when it is located in the area between the source and the receiver. Consequently, one should pay attention to the sound speed profile near the surface above the source and the receiver in ocean acoustic tomography.
A New Method of Calculating Radiation Impedance for Vibrating Surface with Finite Baffle
Authors: Kim Moo-Joon , Kim Chun-Duck , Ha Kang-Lyeol
Published: October 2002

In this paper, by defining a vibrating surface to be a set of small point sources, a new calculation method for the rectangular vibrating surface with a finite baffle is suggested by considering the effect of the finite baffle on the source strength of each point source. As an example, the variation in self-radiation impedance for a rectangular vibrating surface is calculated based on the size of the baffle.