bluuebunny/crossref_metadata_2025 huggingface dataset:
A two-sided approach to estimate heat transfer processes within the active layer of the Murtèl–Corvatsch rock glacier
Authors: Scherler M. , Schneider S. , Hoelzle M. , Hauck C.
Published: March 2014

Abstract. The thermal regime of permafrost on scree slopes and rock glaciers is characterized by the importance of air flow driven convective and advective heat transfer processes. These processes are supposed to be part of the energy balance in the active layer of rock glaciers leading to lower subsurface temperatures than would be expected at the lower limit of discontinuous high mountain permafrost. In this study, new parametrizations were introduced in a numerical soil model (the Coup Model) to simulate permafrost temperatures observed in a borehole at the Murtèl rock glacier in the Swiss Alps in the period from 1997 to 2008. A soil heat sink and source layer was implemented within the active layer, which was parametrized experimentally to account for and quantify the contribution of air flow driven heat transfer on the measured permafrost temperatures. The experimental model calibration process yielded a value of about 28.9 Wm−2 for the heat sink during the period from mid September to mid January and one of 26 Wm−2 for the heat source in the period from June to mid September. Energy balance measurements, integrated over a 3.5 m-thick blocky surface layer, showed seasonal deviations between a zero energy balance and the calculated sum of the energy balance components of around 5.5 Wm−2 in fall/winter, −0.9 Wm−2 in winter/spring and around −9.4 Wm−2 in summer. The calculations integrate heat exchange processes including thermal radiation between adjacent blocks, turbulent heat flux and energy storage change in the blocky surface layer. Finally, it is hypothesized that these deviations approximately equal unmeasured freezing and thawing processes within the blocky surface layer.
ACCURACY ANALYSIS FOR AUTOMATIC ORIENTATION OF A TUMBLING OBLIQUE VIEWING SENSOR SYSTEM
Authors: Stebner K. , Wieden A.
Published: March 2014

Abstract. Dynamic camera systems with moving parts are difficult to handle in photogrammetric workflow, because it is not ensured that the dynamics are constant over the recording period. Minimum changes of the camera’s orientation greatly influence the projection of oblique images. In this publication these effects – originating from the kinematic chain of a dynamic camera system – are analysed and validated. A member of the Modular Airborne Camera System family – MACS-TumbleCam – consisting of a vertical viewing and a tumbling oblique camera was used for this investigation. Focus is on dynamic geometric modeling and the stability of the kinematic chain. To validate the experimental findings, the determined parameters are applied to the exterior orientation of an actual aerial image acquisition campaign using MACS-TumbleCam. The quality of the parameters is sufficient for direct georeferencing of oblique image data from the orientation information of a synchronously captured vertical image dataset. Relative accuracy for the oblique data set ranges from 1.5 pixels when using all images of the image block to 0.3 pixels when using only adjacent images.
METROLOGY OF IMAGE PROCESSING IN SPECTRAL REFLECTANCE MEASUREMENT BY UAV
Authors: Honkavaara E. , Hakala T. , Markelin L. , Peltoniemia, J.
Published: March 2014

Abstract. Remote sensing based on unmanned airborne vehicles (UAVs) is rapidly developing field of technology. For many of potential UAV remote sensing applications, accurate reflectance measurements are required. Overall objective of our investigation is to develop a SI-traceable procedure for reflectance measurement using spectrometric image data collected by an UAV. In this article, our objective is to investigate the uncertainty propagation of image data post-processing. We will also present the first results of three traceable UAV remote sensing campaigns.
PERFORMANCE OF LARGE-FORMAT DIGITAL CAMERAS
Authors: Jacobsen K.
Published: March 2014

Abstract. Based on test blocks and standard production blocks Z/I Imaging DMCII-140, 230 and 250 as well as UltraCam Eagle images have been analyzed by bundle block adjustment with self calibration. By analysis of image coordinate residuals it is possible to check remaining systematic image errors and to update the set of additional parameters to the required combination. The Hannover program BLUH is using a basic set of 12 additional parameters which is a combination between geometric parameters and Fourier parameters in polar coordinates. In addition it is necessary to use a set of special additional parameters for the combination of the 9 UltraCam sub-CCDs. CCDs are often not flat enough, causing a bending of the edges. For the correct handling of such effects, special additional parameters are required to eliminate or at least reduce remaining systematic effects at image corners. For all DMCII-blocks with 5cm, 7cm, 9cm and 20cm GSD the root mean square size of the systematic image errors with 0.05pixels is very small. Only the basic set of 12 additional parameters is required, the special parameters for the image corners did not improve the accuracy determined with independent check points. Against former results with UltraCam images the monolithic stitching of the panchromatic sub-images to the green image improved the image geometry, nevertheless for reaching the highest accuracy the full set of 52 additional parameters is required, leading to systematic image errors in the root mean square of approximately 0.2pixels. This seems to be small, but it is causing a model deformation up to more as 1.0 GSD in the height, while in the case of the DMCII-images the model deformation did not exceed 0.2 GSD in Z. The major reason for the UltraCam Eagle image deformation seems to be caused by corner effects of the green reference image. Such an effect can be avoided with a better calibration. The DMCII and the UltraCam Eagle images were improved by the firm ware for edge enhancement, influencing also the effective image resolution, determined by edge analysis. No real loss of the effective against the nominal resolution can be seen. Nevertheless the UltraCam Eagle images are a little noisy, which may be caused by the edge enhancement and by the imaging in January.
Utilizing Conjoint Analysis to Develop Breeding Objectives for the Improvement of Pasture Species for Contrasting Environments When the Relative Values of Individual Traits Are Difficult to Assess
Authors: Smith Kevin F. , Fennessy Peter F.
Published: March 2014

Despite the large number of active programs breeding improved forage plants, relatively little is known about the weightings that breeders consciously or sub-consciously give to specific traits when selecting individual plants, or that agronomists and producers use when assessing the relative merits of contrasting cultivars. This is in contrast to most modern animal breeding programs where the relative merits of novel genetics may be assessed against an index-based breeding objective. There are numbers of reasons why these technologies have not been used widely in plant breeding although applications in forest tree breeding are relatively common. A first step in defining breeding objectives for forage species can be to define the relative importance of specific traits and to interpret how these contribute to the relative potential advantage to a new plant or cultivar. One method of defining these weightings is through surveys of users followed by analyses of their combined experience. Therefore in this study, we have assessed the usefulness of discrete choice techniques in the development of weightings for specific traits in forage plant improvement based on views of both expert users (agronomists and farm consultants) and farmers who were asked to define their relative priorities when considering the renovation of a pasture. The surveys were conducted in three distinct regions of, or environments within, Australia of special relevance to meat production from beef and sheep (high rainfall, temperate (inland), and Mediterranean). In summary this study defines the focus of breeding objectives and selection criteria for different pasture species across production systems.
Demographics, Health-Care Utilization, and Substance Use Profiles of Older Adults in Canada’s Lowest Income Neighbourhood
Authors: Sztramko Richard , Feng Cindy , Kerr Thomas , Milloy M.J. , Wood Evan
Published: March 2014

BackgroundThis study aimed to determine the baseline demographics, health status, and drug use profiles of current and former substance- using older adults in Vancouver’s Downtown Eastside.MethodsData were derived from two U.S. National Institutes of Health-funded cohort studies of current and former illegal drug users in Vancouver’s Downtown Eastside. We used logistic regression of cross-sectional data obtained between June and November 2008 to calculate odds ratios and identify factors that were more commonly associated with cohort members being older adults (greater than or equal to age 50).Results214 subjects (25%) were greater than or equal to age 50 upon study enrollment. Females (Adjusted Odds Ratio [AOR]: 0.50; 95% CI: 0.34–0.75) and individuals who reported Aboriginal ancestry (AOR: 0.49; 95% CI: 0.33–0.72) were less likely to be in the older cohort. Individuals with higher income (AOR: 2.07; 95% CI: 1.16–3.68 per $1,000), and those with a regular place to stay were more likely to be in older cohort (AOR: 3.39; 95% CI: 1.90–6.06). Older participants accessed family physicians more frequently (OR: 1.47; 95% CI: 1.01 – 2.16) and were more likely to be actively taking (OR: 3.34; 95% CI 1.71–6.55) or have taken (OR 3.21; 95% CI 1.58–6.53) HIV antiretroviral therapy. There were no differences between groups in regard to injection drug use status or daily alcohol intake.ConclusionsOlder current and former illegal drug users in a major inner city Canadian centre have different demographic, health-care,and drug utilization profiles. Further studies in this population are warranted.
High HIV incidence in the postpartum period sustains vertical transmission in settings with generalized epidemics: a cohort study in Southern Mozambique
Authors: De Schacht Caroline , Mabunda Nédio , Ferreira Orlando C , Ismael Nália , Calú Nurbai , Santos Iolanda , Hoffman Heather J , Alons Catharina , Guay Laura , Jani Ilesh V
Published: March 2014

Introduction

Acute infection with HIV in the postpartum period results in a high risk of vertical transmission through breastfeeding. A study was done to determine the HIV incidence rate and associated risk factors among postpartum women in Southern Mozambique, where HIV prevalence among pregnant women is 21%.

Methods

A prospective cohort study was conducted in six rural health facilities in Gaza and Maputo provinces from March 2008 to July 2011. A total of 1221 women who were HIV‐negative on testing at delivery or within two months postpartum were recruited and followed until 18 months postpartum. HIV testing, collection of dried blood spot samples and administration of a structured questionnaire to women were performed every three months. Infant testing by DNA‐PCR was done as soon as possible after identification of a new infection in women. HIV incidence was estimated, and potential risk factors at baseline were compared using Poisson regression.

Results

Data from 957 women were analyzed with follow‐up after the enrolment visit, with a median follow‐up of 18.2 months. The HIV incidence in postpartum women is estimated at 3.20/100 women‐years (95% CI: 2.30–4.46), with the highest rate among 18‐ to 19‐year‐olds (4.92 per 100 women‐years; 95% CI: 2.65–9.15). Of the new infections, 14 (34%) were identified during the first six months postpartum, 11 (27%) between 6 and 12 months and 16 (39%) between 12 and 18 months postpartum. Risk factors for incident HIV infection include young age, low number of children, higher education level of the woman's partner and having had sex with someone other than one's partner. The vertical transmission was 21% (95% CI: 5–36) among newly infected women.

Conclusions

Incidence of HIV is high among breastfeeding women in Southern Mozambique, contributing to increasing numbers of HIV‐infected infants. Comprehensive primary prevention strategies targeting women of reproductive age, particularly pregnant and postpartum women and their partners, will be crucial for the elimination of paediatric AIDS in Africa.
Diagnostics of expanding mesoplasmas originated from a miniaturized inductively coupled plasma and their application to Si etching
Authors: Chen Qiang , Tsuchiya Shoichi , Ichiki Takanori
Published: March 2014

A miniaturized inductively coupled plasma (m-ICP) was generated at atmospheric pressure and introduced into an expansion chamber at a reduced pressure ranging from 10 to 1000 Pa to produce expanded mesoplasmas. The fundamental parameters of the m-ICP and the downstream mesoplasma were investigated by optical emission spectroscopy and Langmuir probe measurement. When the m-ICP entered the expansion chamber, it diffused into the surrounding area and the electron density decreased from 1013 to 109–1010 cm−3. Furthermore, Si etching in mesoplasmas was performed by adding SF6 to Ar plasmas. By changing the gas pressure, anisotropic etching with a vertical-to-horizontal etch rate ratio of 2.5 was achieved at 60 Pa with a vertical etch rate of 2.7 µm/min. In addition, the anisotropy was improved to 8 by introducing 10 sccm H2 into the Ar/SF6, which is ascribed to the reduction of sidewall undercutting resulting from the scavenging effect of fluorine atoms by atomic H.
High-density microwave plasma source using negative-permeability metamaterial with tuned wave attenuation
Authors: Nakamura Yoshihiro , Sakai Osamu
Published: March 2014

High-density plasma generated by waves with efficient wave power consumption is suitable for various dry processes. However, when we use microwaves as power sources, the electron density in a conventional microwave plasma source is limited within the range in which the permittivity of the plasma is positive. To overcome this drawback, a negative refractive index phenomenon is applicable, in which the permittivity and permeability are both negative and microwaves can propagate even in a negative-permittivity space with high electron density. In this report, we demonstrate a promising scheme for the efficient generation of high-density plasma by propagating microwaves in a negative-permeability space, and show the experimental observation of the enhancement of plasma generation using the lower imaginary part of the permeability.
Surface analysis of polysilicon gate etching by pulsed-microwave plasma
Authors: Matsui Miyako , Morimoto Michikazu , Ikeda Norihiko , Yokogawa Kenetsu
Published: March 2014

The mechanism of highly selective etching by a pulsed-microwave electron-cyclotron-resonance plasma was investigated by analyzing surface-reaction layers formed on nonpatterned poly-Si and SiO2 samples and gate-patterned samples with a gate width of 32 nm. The samples were etched by using an HBr/O2/Ar/CH4 gas chemistry and varying the duty cycle of the pulsed microwave. The reaction layers, which were revealed as a hydrocarbon layer on a SiBr
x
O
y
layer, were analyzed by X-ray photoelectron spectroscopy. The upper layer was a hydrocarbon layer, which protected SiO2 from ion bombardment and also prevented Br flux from being supplied to the SiO2. The lower layer was a SiBr
x
O
y
layer, which suppressed the etching of the underlying Si substrate. The formation of the hydrocarbon layer was controlled by the duty cycle of the microwave plasma. Etch stop, which occurred at a low peak-to-peak voltage (wafer bias) of the continuous microwave plasma, was prevented by controlling the thickness of the hydrocarbon layer in the pulsed-microwave plasma. Gate-oxide punch-through, which occurred at a high peak-to-peak voltage of wafer bias in the case of the continuous microwave plasma, was also prevented in the case of the pulsed microwave plasma by forming reaction layers with high C/Br ratio.
Effects of straggling of incident ions on plasma-induced damage creation in “fin”-type field-effect transistors
Authors: Eriguchi Koji , Matsuda Asahiko , Takao Yoshinori , Ono Kouichi
Published: March 2014

We investigated the plasma-induced physical damage (PPD) mechanism in a field-effect transistor (FET) with a fin-type channel, called FinFET. Compared to PPD in planar metal–oxide–semiconductor field-effect transistors (MOSFETs), such as Si loss or Si recess formed by energetic ion bombardment during plasma processing followed by the subsequent wet-etch stripping, it was predicted that PPD in FinFETs are generated primarily by a stochastic process called straggling of incident ions. During the etching of a fin structure in a FinFET, an impinging ion penetrates into the crystalline Si region to be etched, not only in the vertical direction but also in the lateral direction, resulting in lateral damage in the sidewall region, that is, the bulk fin. The damage layer generation mechanism in the fin structure was modeled on the basis of range theory. A molecular dynamics simulation was performed for noble and halogen species impacting on a Si fin structure to verify the proposed mechanism. The calculated results showed that ions with lighter masses and higher incident energies induced a larger amount of damage in the bulk fin owing to the nature of straggling phenomena. It should be noted that the PPD in the bulk fin may lead to latent defect sites in the channel region, and hence to operating speed degradation, which is a problematic concern for high-performance FinFETs.
Plasma process induced physical damages on multilayered magnetic films for magnetic domain wall motion
Authors: Kinoshita Keizo , Honjo Hiroaki , Fukami Shunsuke , Nebashi Ryusuke , Tokutome Keiichi , Murahata Michio , Miura Sadahiko , Kasai Naoki , Ikeda Shoji , Ohno Hideo
Published: March 2014

The effect of ion irradiation on magnetic domain wall motion (DWM) in a perpendicularly magnetized Co/Ni multilayered film was investigated. The DWM in the Co/Ni multilayered film was sometimes inhibited owing to damage in Co/Ni induced by ion irradiation from Ar/NH3/CO plasma during the etching of the upper layer of a Co/Pt multilayered film depending on the etched depth over Co/Ni. When the DWM was disturbed, modifications of crystallinity were observed by transmission electron microscopy (TEM) near the etched surface region of Co/Ni. Also, the segregation of Pt which was knocked on from the upper layer of Co/Pt, was observed by energy dispersive X-ray line-scan analysis by TEM (TEM–EDX). In contrast to that, the sample which had fine DWM property showed clear lattice image of Co/Ni. A Monte Carlo simulation of Ar+ ion irradiation predicted an atom-displacement range of about 3.5 nm depth from the etching surface when the ion acceleration voltage was 900 V. It was deep enough to degrade the area near the top region of the Co/Ni multilayered magnetic thin film. Eliminating these physical modifications during the etching process would be the key to the fabrication of reliable nonvolatile devices using domain wall motion.
Numerical simulation of electric double layer in contact with dielectric barrier discharge: Effects of ion transport parameters in liquid
Authors: Shirafuji Tatsuru , Nakamura Akihiro , Tochikubo Fumiyoshi
Published: March 2014

The spatiotemporal distribution of charged particles has been investigated through numerical simulation of charged particle behavior in gas and liquid phases in the dielectric barrier discharge of Ar gas in contact with a liquid. In the case of a liquid with a low ion concentration such as de-ionized water, the amount of liquid-phase ions generated by electron or ion irradiation from gas-phase plasma is higher by approximately one order of magnitude than that in the pure electric double layer formed only with the potential difference between the top and bottom of the liquid. When the molecular weight of the ions is larger, the residence time of the ions at the liquid surface becomes longer. If the molecular weight of positive and negative ions is different, heavier ions become dominant at the liquid surface. These characteristics are pronounced by employing a higher frequency voltage, which implies the possibility of preferential reactions at the plasma-liquid interface.
Characteristic of Leaky Surface Waves Propagating on Li2B4O7 Substrate with a Thin Aluminum Plate
Authors: Murota Masao , Shimizu Yasutaka
Published: March 2014

Characteristics of leaky surface waves propagating on a Li2B4O7 substrate with a thin aluminum plate are theoretically calculated. Phase velocity, TCD, and propagation loss are shown changing the thickness of the aluminum plate on a (0°, θ, 75°)-cut for 65°≤θ≤8°. The (0°, 73°, 75°)-cut has zero TCD for both electrically open and aluminum short surfaces with H/λ=0.02 thickness. Temperature dependence of fractional time delay(Δτ/τ) and propagation loss is also shown.
Investigation of Impulse Response for an Interdigital Surface-Acoustic-Wave Transducer
Authors: Kojima Toshihiro , Obara Hiroyuki , Shibayama Kimio
Published: March 2014

The improved equivalent circuit model for a SAW interdigital transducer which we proposed in a previous paper contains an energy storage effect in addition to usual second order effects, and appropriately expresses the metallization effect.
Using this model, this paper describes the relations between the impulse responses and the various second order effects for an IDT with an arbitrary metallization ratio on LiNbO3. To investigate in detail the influence of the second order effects on the performance of an IDT, figures of the characteristic responses are contrasted in both the frequency and time domains.
Characterization of Ion Implanted Layer Using Ion-Induced Acoustic Signal
Authors: Ogiso Hisato , Nakano Shizuka , Nagata Yoshihiko , Yamanaka Kazushi , Koda Toshio
Published: March 2014

The acoustic signal induced by an intensity modulated 3 MeV Si2+ ion beam was observed by both post-process and in-process measurements to investigate the influence of the 3 MeV Si ion implanted layer into Al plate on the ion acoustic signal (IA signal). A phase difference between IA signals at the implanted region and unimplanted region was found. Therefore, the phase of IA signal can be applied to characterization of the ion implanted layer. Influence on the amplitude was not clear, however so this seems hard to use for the characterization.
Intermodulation in SAW Filters for Cellular Radio Systems
Authors: Hosaka Norio , Yuhara Akitsuna , Yamada Jun , Kobayashi Takao
Published: March 2014

Intel-modulation between transmission and spurious signals in multi-IDT-type SAW filters on 36° Y–X LiTaO3 substrate, which are used for antenna duplexers in cellular telephones, is studied. The experiments used two input signals of 835 MHz transmission and 790 MHz spurious signals applied to the filter, and a third-order intermodulation signal at 880 MHz caused by the nonlinear effect coming into the receiving band. These intermodulation characteristics are influenced by applied power and ambient temperature. The experimental results show that intermodulation level is closely related to applied power level and temperature of the filter.
The Polishing Effect of ZnO Thin Films on SAW Filters
Authors: Kadota Michio , Kondo Chikashi , Ikeda Toshiaki , Kasanami Tohru
Published: March 2014

SAW filters in a structure of ZnO/IDT/glass, have periodic convex and concave roughness on the surface of ZnO thin films which is caused by IDT electrodes. This investigation reports that the convex and concave roughness affects the SAW velocity, and mechanical polishing of the ZnO thin films has great effect on SAW filter frequency characteristics.
Ultrasonic Levitation by Stepped Circular Vibrating Plate
Authors: Otsuka Tetsuro , Higuchi Kazutaka , Seya Koichiro
Published: March 2014

A high intensity ultrasound field was produced by a new type sound source called a stepped circular vibrating plate, and the experimental results on levitation in air by ultrasound energy are described. The density of samples, frequencies and sample dimensions were varied.
The minimum threshold of sound pressure required for levitating the samples was found proportional to sample density, and was also inversely proportional to the ultrasonic frequency used.
Driving and Welding Characteristics of An Ultrasonic Butt Welding System Using A Large Capacity Power Amplifier
Authors: Tsujino Jiromaru , Ueoka Tetsugi , Tsuboi Shunichi
Published: March 2014

Driving condition and welding characteristics of an ultrasonic butt welding system are studied. The ultrasonic vibration source used has eight 19 kHz bolt-clamped Langevin type PZT transducers of 50 mm diameter and is driven by a 50 kW static induction thyristor power amplifier. Adequate values of matching circuit according to welding load and vibration amplitude of a vibration source must be used to improve power factor of the welding system and to obtain maximum effective power and good welding results. Welding specimens of 6 mm thick aluminum, anticorrosive aluminum and copper plates are successfully joined end to end.
Excitation of a Progressive Wave in a Flexurally Vibrating Transmission Medium
Authors: Tomikawa Yoshiro , Adachi Kazunari , Hirata Hiroshi , Suzuki Takanori , Takano Takehiro
Published: March 2014

Excitation of a progressive wave in a straight and thin bar vibrating in the flexural mode can be utilized to construct a transport device such as a parts-feeder. A new method to excite the progressive wave is proposed herein which has been proved possible by simulation and experiment. Excitation of a progressive wave without utilizing the concept of impedance matching in a transmission line is done using two adjacent modes of flexural vibration.
Surface Acoustic Wave Paramagnetic Resonance in Iron Doped-LiNbO3
Authors: Cho Yasuo , Horie Hideyoshi , Yamanouchi Kazuhiko
Published: March 2014

We studied surface acoustic wave-acoustic paramagnetic resonance (SAW-APR) of Fe2+ doped LiNbO3. Firstly, we theoretically calculated the parameters of spin Hamiltonian. From these calculations, we found that the trigonal axial field splits the triplet of lower orbital energy level in a cubic octahedral field into a singlet and a doublet. We also calculated spin-lattice coupling coefficient G

i
j
and, finally, measured the temperature dependency of a SAW-APR spectrum of LiNbO3:Fe2+. We were able to observe an absorption line at about 20 K as predicted from theoretical considerations.
Dumbbell-Shaped Small-Sized Hybrid Ultrasonic Motor
Authors: Umeda Mikio , Ohnishi Kazumasa , Nakamura Kentaro , Kurosawa Minoru , Ueha Sadayuki
Published: March 2014

A dumbbel-shaped torsional vibrator is studied in the construction of a small hybrid transducer type ultrasonic motor whose stator consists of a Langevin type torsional vibrator and a longitudinal piezoelectric actuator. Two kinds of stators 20 mm in diameter are designed by FEM for this construction. These motors proved to operate successfully as expected and maximum torque of 1kgf·cm.
Modeling of Progressive Wave Type Ultrasonic Motor
Authors: Suzuki Takayuki , Kamano Takuya , Kazuhara Toshihiro
Published: March 2014

This paper describes an improved model of the progressive wave type ultrasonic motor to explain the nonlinear characteristics due to the internal friction. Some responses of motor speed to the applied voltage are calculated employing the proposed model. The calculated results are compared with the measured results.
A Study of a Vehicle Ground Speed Sensor Using the Doppler Effect of Ultrasonic Waves
Authors: Kobayashi Hiroshi , Kimura Toshiya , Negishi Masami
Published: March 2014

A study was made to examine the Doppler effect efficiency and the Doppler signal measurement. The results led to determination of the two best conditions for the transmission of the ultrasonic wave signal and reception of the Doppler signal. The transmission condition was found to be mostly dependent on wavelength. A new sensing method for the Doppler signal, the reception frequency being fixed at the most reasonable frequency determined by the best transmission conditions, was effective in raising the signal's measurement accuracy.
An Ultrasonic Pulse Compression System for Nondestructive Testing Using Complementary Series Phase Modulation
Authors: Wadaka Shusou , Nagatsuka Tsutomu , Misu Koichiro , Urasaki Shuji , Koike Mitsuhiro
Published: March 2014

An ultrasonic pulse compression system is presented, which employs complementary series phase modulated signals as transmit signals to obtain theoretically zero range sidelobes and high efficiency. In correlation based signal processing, echoes are correlated with reference signals that have the same wave forms as the echoes. The effectiveness of this signal processing over the conventional one using transmit signals as reference signals is verified by experiments.
Measurement of Thermal Ripplon on Liquid Surface by Light Scattering Technique
Authors: Sakai Keiji , Choi Pak-Kon , Tanaka Hajime , Takagi Kenshiro
Published: March 2014

A new experimental system of light scattering was developed to measure the propagation of the thermal surface-tension wave (ripplon) on a liquid surface. The upper limit of the measurement is 106 m-1 in wave number which is one decade higher than the conventional light scattering method. Frequency and damping constant measured for ethanol at the wave number range k>105 m-1 show an anomalous dispersion which cannot be explained by a classical hydrodynamic theory.
Superresolved Image Restoration of Multifrequency Holographic Images
Authors: Miyashita Toyokatsu , Hashiguchi Hiroyuki
Published: March 2014

We show that the L1-norm minimization procedure used in seismic signal processing is also useful for the image reconstruction of point-targets. We applied this procedure to the holographic images of the point-targets, which typically have a diffraction limited resolution of a few wavelengths. Minimizing the L1-norm of real and imaginary parts of the images of complex number in the region of interest, we obtained superresolved images whose resolution was, in principle, determined only by the pixel spacing (e.g., a tenth part of one wavelength). We performed the L1-norm minimization with a linear programming of a modified simplex method.
Analysis of VHF Ultrasonic Resonator
Authors: Nakajima Haruhiko , Snindoh Jun
Published: March 2014

The behavior of a VHF ultrasonic resonator is analyzed with a one-dimensional three layer (solid-liquid-solid) model, and resonant frequencies and the half-value width (HVW) are calculated. In contrast to an ideal liquid resonator, HVW periodically depends on the thickness of the liquid layer, which can reproduce the scattered HVW data of our previous experiment. The reason why the VHF resonator has sharper resonant peaks than the ideal liquid resonator is also explained.
A Characterization of Ultrasonic Power Spectrum by Fractal Analysis–Imaging by Fractal Dimension–
Authors: Kikuchi Tsuneo , Kiryu Shogo , Sato Sojun , Miura Hajime
Published: March 2014

The shape of the power spectrum of scattering wave is affected by position distribution of the scatterers (mean spacing and irregularity) constructing the medium. Fractal analysis is an appropriate tool for estimating this shape and gives us much information on the internal structures of the medium. This paper describes imaging experiments and an image obtained by the fractal dimension of the power spectrum. In the images obtained by this method it is easier to discriminate the different internal structures than in those obtained by conventional intensity imaging.
X-ray Absorption Near Edge Structure (XANES) of CuInSe2, Brass and Phosphor Bronze by Photoacoustic Method
Authors: Toyoda Taro , Masujima Tsutomu , Shiwaku Hideaki , Iida Atsuo , Kawata Hiroshi , Ando Masami , Nakanishi Hisayuki , Endo Saburo , Irie Taizo
Published: March 2014

The X-ray photoacoustic absorption spectrum near Cu K-edge of CuInSe2, brass and phosphor bronze has been measured together with that of pure Cu metal as a reference using synchrotron radiation. It is shown that the information derived from X-ray absorption near edge structure (XANES) is also included in the X-ray photoacoustic absorption spectrum which reflects heat generation processes in material.
Applications of Integrated Collinear Acousto-Optic Devices to Matrix Multiplication
Authors: Kanayama Yukihiro , Goto Nobuo , Miyazaki Yasumitsu
Published: March 2014

Integrated collinear acousto-optic devices are investigated for their application to numerical processing. Improvements of the filter response that is important to optical wavelength multiplexing are discussed. Crosstalk is caused by sidelobes of the filter response. The undesirable sidelobes are suppressed by integrating two elements or by modifying the SAW waveguide. Matrix-vector multiplication in analog representations is demonstrated with a slab-type collinear acousto-optic device.
Photoacoustic Spectroscopy Detected by Piezoelectric Transducer with Resonator
Authors: Hibaru Kunio , Morimoto Jim , Miyakawa Toru
Published: March 2014

Photoacoustic spectra of CdS were detected by a piezoelectric transducer attached to a resonator plate. The advantages of this method are (1) only signals generated by photoacoustic deformation of the sample are detected, (2) the spurious signals due to scattered light on the transducer are eliminated and (3) sensitivity is enhanced by the use of resonance at higher chopping frequencies. Spectra taken at chopping frequencies 30 Hz and 80 Hz reproduce the main features observed in the PA spectrum taken by microphone method. We found a dip in spectra at around 510 nm related to band edge emission.
Variable Low Temperature Acoustic Microscopy and its Application to Polymers
Authors: Yamanaka Kazushi , Nagata Yoshihiko , Koda Toshio
Published: March 2014

A low temperature acoustic microscope has been developed to study mechanical and acoustic property of materials at temperatures from 30°C to -94°C. In the application to a 30 µm thick PVDF film, sharpening of the half wavelength resonance of longitudinal wave across the film was observed by cooling. For 0.6 mm thick epoxy adhesive layer, structures not visible at ambient temperature became clear when the sample was cooled to -30°C. This improvement was explained in terms of the decrease in the attenuation loss and impedance mismatching loss. Based on those results, temperature controlled acoustic imaging is proposed for nondestructive evaluation of polymers.
Pressurized Superfluid 4He Acoustic Microscopy
Authors: Karaki Koichi , Suzuki Masaru , Okuda Yuichi
Published: March 2014

An acoustic microscope has been developed which makes use of pressurized super fluid helium as an acoustic coupling medium. Acoustic micrographs were taken using pure super fluid 4He under saturated vapor pressure at 0.2 K and under 25 atm at 0.2 K and 1.9 K, for the frequency of 400 MHz. By pressurizing liquid 4He, the acoustic attenuation decreases, the efficiency of the antireflection coating increases, and the power level of saturation caused by nonlinearity of the super fluid 4He is raised. A good signal-to-noise ratio of imaging is thus obtained.
Ultrasonic Transducer Employing a ZnO-film/Al-foil Composite Structure for Non-Destructive Testing
Authors: Yamamoto Mitsuru , Hashimoto Ken-ya , Rajendran Velayutham , Yamaguchi Masatsune
Published: March 2014

The paper proposes high frequency ultrasonic transducers employing a ZnO-film/Al-foil composite structure for application to non-destructive testing (NDT). Analysis suggested the possibility of realising wide bandwidth and high efficiency transducers by properly determining the Al foil and ZnO film thicknesses. It was experimentally shown that, being air-backed, the transducer efficiently launches ultrasonics into water at 102 MHz. No spurious response was observed, and a -3 dB bandwidth of 6.3 MHz was obtained. A simple experiment to confirm the applicability of the transducer to NDT was also performed.
Equivalent Circuit of Piezoelectric Transducers with Spatially Nonuniform Properties
Authors: Sato Masahiro , Yoshida Norinobu , Fukai Ichiro
Published: March 2014

The paper shows how transducers having nonuniform properties may be represented by an equivalent circuit. The circuit is constructed by cascade connection of many fundamental equivalent circuits made up of small transmission lines and lumped elements. Under the condition that wavelengths are much longer than the small transmission lines, the fundamental circuit approximates the constitutive relation equations of a small section of the transducer. Formulation for transient calculation is performed easily by Bergeron's method. The numerical result proved to be in good agreement with the analytical solution.
Control of Parametric Amplification Using the Nonlinear Vibration of Bubbles Under Water
Authors: Asada Takaaki , Watanabe Yoshiaki , Urabe Yasumasa
Published: March 2014

Strong nonlinearity appearing in bubble vibration is proposed to control parametric amplification over a wide range. The equivalent nonlinearity parameter β
d
for the difference frequency sound of the parametric array in bubbly medium is defined. Bubble condition where β
d
is controllable over a wide range by varying bubble density are theoretically discussed and experiments are performed. It is confirmed that SPL of the difference frequency can be easily controlled by the bubble conditions. Waveform distortion is clearly observed on a time profile at a short distance from the sound source.
A Low Frequency Underwater Sound Source with an Acoustic Reel Shape Resonator
Authors: Hachiya Hiroyuki , Ohtsuki Shigeo , Okujima Motoyoshi
Published: March 2014

In large scale monitoring techniques of the ocean such as ocean acoustic tomography, a wide band low frequency sound source is required. In this paper, a new type of construction of a low frequency sound source in which the cylindrical transducer is put between two metal circular plates is proposed. This source has wide band resonance and high reliability at high power operation. The source characteristics of resonance frequency and quality factor Q are examined using a theoretical model. Experimental results are compared with theoretical results, and this low frequency sound source is found to be valid in deep seas.
Anisotropy of Sound Speed and Absorption Coefficient of FRP Plate
Authors: Nakanishi Toshiyuki , Kikuchi Toshiaki , Hasegawa Akio , Takahashi Sumio
Published: March 2014

The variation of sound speed and absorption coefficient are very important parameters in selecting materials for sonar domes. This paper describes the results of measurement on these two factors in a FRP plate composed of resin and layers of polythylene cloth, and it is shown that they increase according to the increase of the refraction angle. These factors are determined by selecting their values in the theoretical calculation so as to agree with the measured data of transmission loss. The measurement was carried out by water immersion method at various frequencies and incident angles.
Estimation of Thickness of Ferroelectric Inversion Layers in LiTaO3 Plates by Measuring Piezoelectric Responses
Authors: Nakamura Kiyoshi , Hosoya Masahiko , Shimizu Hiroshi
Published: March 2014

A ferroelectric inversion layer can be formed in LiTaO3 by proton exchange in benzoic acid melts followed by heat treatment at temperatures just below the Curie point. This paper presents a method of nondestructively estimating the thickness of the inversion layer by measuring the piezoelectric responses associated with the thickness modes of vibration. It is demonstrated that the estimated values of inversion layer thickness agree well with those measured by microscope observation of etched cross sections of LiTaO3 plates.
An Analysis of Spurious Vibrations for a New Shape Length Extensional Mode Quartz Crystal Resonator
Authors: Kawashima Hirofumi , Nakazato Mitsuhiro
Published: March 2014

This paper describes the spurious vibrations for an innovative shape for a length extensional mode quartz crystal resonator. It consists of a vibrational portion and two supporting portions. The objects of this paper are to clarify theoretically the spurious vibrations which are very dependent on thickness and width of the vibrational portion, and to provide resonators with no jump of resonant frequency or series resistance versus temperature. The predicted results are then compared with the measured values. It is shown that resonators designed using the suggested optimum thickness-width relations have no discontinuities of frequency or resistance versus temperature.
Equivalent Circuit and Construction of Piezoelectric Vibratory Gyroscopes Using a Flexurally-Vibrating Resonator with a Square Cross Section
Authors: Sugawara Sumio , Konno Masashi , Kudo Subaru , Yoshida Tomio
Published: March 2014

A flexurally-vibrating resonator with a square cross section can be applied to an angular rate sensor of a vibratory gyroscope. The relation between the two pairs of vibrational modes in the resonator is considered theoretically by an equivalent circuit considering coordinate transformation, to clarify a method of drive and detection of the resonator as a vibratory gyroscope. New construction and equivalent circuits of a piezoelectric vibratory gyroscope are proposed under the consideration.
An Analysis of Surface-Acoustic-Wave Devices Using Coupling-of-Mode Theory and Finite-Element Method
Authors: Koshiba Masanori , Ohbuchi Kazuhiro
Published: March 2014

A coupling-of-mode theory is described for the analysis of excitation characteristics of interdigital transducers (IDT) for surface acoustic waves (SAW) and of reflection characteristics of SAW gratings. Coupling and transduction coefficients of coupled mode equations can be theoretically determined by applying the finite-element method (FEM) to an infinite array corresponding to an electrically shorted or open IDT. The FEM is also used to calculate the static capacitance for one pair of IDTs. Examples are computed for various types of IDTs and metallic gratings on a 128° Y-X LiNbO3 substrate.
Effects of Aluminum Thickness on the Temperature Characteristics of Leaky Surface Wave Filters on LST-cut Quartz Substrate
Authors: Murota Masao , Hirano Tetsuya , Lam C. S. , Holt D. E. , Shimizu Yasutaka
Published: March 2014

The LST-cut of quartz has better frequency-temperature stability than the conventional ST-cut. In this paper, theoretical temperature dependence of the center frequency and insertion loss of SAW filters on LST-cut quartz is compared with experimental results. Theoretical values including effect of the metallization thickness are in very good agreement with experiments. It is found by theoretical calculation that minimum temperature frequency shift and change of insertion loss are exhibited. These results should be applicable for practical temperature stable LST-cut SAW filters.
SH-Type Leaky Surface Waves on Rotated Y-Cut LiTaO3 Substrates with a Ferroelectric Inversion Layer
Authors: Tourlog Ailie , Nakamura Kiyoshi , Shimizu Hiroshi
Published: March 2014

The SH-type leaky surface wave on a 35° rotated Y-cut LiTaO3 substrate with a ferroelectric inversion layer is theoretically analyzed and the propagation characteristics are described. The calculated results show that the attenuation of the leaky SAW varies periodically with the product of the inversion layer thickness and the wave number, and the leaky wave reduces to a non-leaky surface wave at certain values of the product. The phase velocity of the leaky surface wave decreases and the concentration of the displacement to the surface is improved by a quasi electric-field short-circuiting effect of the domain boundary. It is also shown that the second mode exists in the substrate with a metallized surface.
Design of Phase Shifters for a Group Type Unidirectional Transducer
Authors: Nogami Hiroshi , Shiba Takashi , Noro Yoshihiko , Oda Koji
Published: March 2014

A group type unidirectional transducer (GUT) is useful for a low loss SAW filter. The four-port and two-port network expressions for the GUT are presented, and interaction between the inphase and quadrature ports is revealed analytically. The conditions for perfect unidirectivity are also described. The design procedures of the electrical phase shifters performing perfect unidirectivity are shown both in series and parallel configurations for any geometrical phase shift except π.
SAW Resonators Using Epitaxially Grown Al Electrodes
Authors: Ieki Hideharu , Tada Yutaka , Sakurai Atsushi , Kimura Koji
Published: March 2014

Epitaxially grown Al electrode was obtained on rotated Y cut quartz substrate by vapor deposition. The epitaxial relationship was (311)<2̄33>Al//(032)<100>SiO2. This electrode had very high resistance to stress migration. In SAW resonators, time to failure caused by stress migration was improved by more than 2000 times and power handling capability was increased by at least 10 times over an ordinary polycrystalline Al–Cu electrode. Epitaxially grown Al electrode was also obtained on LST-cut quartz substrate.
Characteristics of Magnetostatic Surface Wave Waveguides for Optical Devices
Authors: Hasegawa Kazuo , Miyazaki Yasumitsu
Published: March 2014

In magnetostatic wave devices, the thickness of a transmission path becomes between 10 and 20 µm due to the excitation of magnetostatic wave. However, the waveguide does not become a single mode for the optical wavelength when it acts as a magneto-optic device, with MO effect by magnetostatic wave. Such a waveguide is undesirable because the performance is diminished due to coupling between higher modes. Then the waveguide in which only the fundamental mode propagates can be constructed with the double magnetic layers. We discussed the configuration of such a waveguide in MSSW-optical devices.
An Acoustical Imaging System Using a Leaky Lamb Wave Transducer
Authors: Sawaguchi Akihiro , Toda Kohji
Published: March 2014

A C-mode acoustical imaging system is constructed by incorporating a leaky Lamb wave device, which has quarterly partitioned and arch-shaped interdigital transducers. The leaky Lamb wave transducer has frequency-dependent radiation angles under multimode operation. For designing the leaky Lamb wave transducer, the transducer efficiency, radiation angle, and the energy distribution rate at the sample surface are considered based on the numerical analysis at the liquid-solid boundary. The usefulness of the system is demonstrated for nondestructive testing to detect a crack on the surface and inside a sample.
Studies on Ultrasonic Vibration Bending of Thin Metal Plates
Authors: Tsujino Jiromaru , Satoh Hajime , Takiguchi Kazuhiro
Published: March 2014

Ultrasonic vibration bending of thin metal plates using a 27 kHz vibration bending die is studied. The vibration die used consists of a longitudinal-to-longitudinal vibration direction converter with four boltclamped Langevin type PZT transducers. Bending specimens used are (1) pure aluminum, (2) anticorrosive aluminum and (3) stainless steel plates. As vibration amplitude of the die increases, springback angle decreases to almost zero at large amplitude and bending angle increases slightly. Surface condition of the bending part is improved and becomes smooth with ultrasonic vibration.
Process of Change from Ultrasonic Wave to Shock Wave in Extracorporeal Shock Wave Lithotripsy Using Piezoceramic Transducer
Authors: Okazaki Kiyoshi , Iwama Nobuyuki , Nomura Satoshi
Published: March 2014

The process of change from ultrasonic wave to shock wave by non-linear effect in a shock wave lithotripter using a piezoceramic transducer was observed by a membrane-type PVDF hydrophone. The peak sound pressure at the focussing point is 1.6 MPa at a 60 V driving voltage. As there is no shock front, this wave cannot disintegrate a stone. At 3.5 kV, a detected waveform which has a shock front is different from that of 60 V and is able to disintegrate a stone. The peak pressure of this shock wave is 110 MPa. The focal zones of ultrasonic and shock waves are 3 mm×19 mm and 1 mm×20 mm, respectively.