bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive and Collaborative Learning in Virtual English Classes
Authors: Li Lan
Published: March 2014

This paper reports the tactile learning experience with simulated 3D learning environments in an English Department at a Hong Kong university. With the belief that multimedia instruction and multimedia learning help the learner’s construction of knowledge (Mayer 2005, p.2), sections of Second Life were embedded into three separately taught English subjects. Various student activities were carefully designed, such as knowledge hunting, intercultural communication, peer assessment and assimilation of workplace tasks. In order to find out if students are motivated to use SL and if learning through a virtual environment is more effective than a traditional classroom or a 2D online environment, a questionnaire survey was conducted among the students. Student feedback was also retrieved from the reflective essays on the virtual learning activities. Positive feedback asserts that SL is an interesting, interactive and entertaining environment for both independent and collaborative learning. SL can be used for the placement of teaching materials, the demonstration of certain functions, initiating instant communication and enabling peer assessment in the learning process. The main difficulties according to the students are motivation, complications with technology and time consumption. On the whole, we regard Second Life as having future promise for facilitating linguistic development. However, usage of the platform requires substantial resource investment in order to ensure adequate design of interfaces and appropriate virtual activities for learning purposes.
Evolving Challenges to the Development and Assessment of Information Literacy Education for Online Safety in Japan
Authors: Saito Nagayuki , Tanaka Ema , Yatsuzuka Eri
Published: March 2014

Seeking a safer Internet environment for minors, the Japanese government enacted a new law in 2008 to promote both protective measures and empowerment activities. Under the act, many entities, including newly established non-profit organizations (NPOs), are working to bring a safer Internet environment to Japan. The Japan Internet Safety Promotion Association (JISPA), one such NPO established in February 2007, has worked to promote a safer Internet environment for minors by providing non-formal learning opportunities through educational materials and events. Efforts to improve children’s online safety have evolved from offering e-learning content and guidelines to holding workshops in the real world. JISPA’s activities are characterized by its evolving process, in which changes are made based on feedback and assessments of their activities, such as e-learning content from “Mobami” and discussion workshops for high school students. Furthermore, JISPA has become a hub among the concerned parties including telecom carriers, information technology (IT) companies, and individuals; it has 186 members as of November 2013.
Iridaceae
Authors: Manning J. C. , Goldblatt P.
Published: March 2014

Tritonia cedarmontana and T. linearifolia (Crocoideae), two new species from the Cape Floristic Region; T. lineata var. parvifolia included in T. gladiolaris; and the correct author citation for T. strictifolia.
Marchantiophyta
Authors: Van Rooy J. , Phephu N. , Perold S. M.
Published: March 2014

New liverwort distribution records in South Africa.
Molluginaceae
Authors: Manning J. C. , Goldblatt P. , Forest F.
Published: March 2014

Adenogramma natans, a remarkable new aquatic species from Western Cape, South Africa.
Pteridophyta–Thelypteridaceae
Authors: Crouch N. R.
Published: March 2014

Metathelypteris burrowsiorum, a new species from Swaziland and a first genus record for southern Africa.
Ornithoglossum pulchrum (Colchicaceae: Colchiceae), a new species from southern Namibia
Authors: Snijman D. A. , Nordenstam B. , Mannheimer C.
Published: March 2014

We describe a new species in the sub-Saharan genus Ornithoglossum Salisb. from southern Namibia. Ornithoglossum pulchrum from near Aus, is remarkable in having bright to dark pink flowers, a feature previously unknown in the genus. The perigone is almost concolorous apart from a contrasting, pale yellow nectary region, narrowly outlined with darker red, near the base of each tepal. The undulate leaves together with the long filaments, which are nearly as long as the tepals, suggest a relationship with O. undulatum, a widespread species in the western parts of southern Africa, and O. zeyheri from Namaqualand and the northwestern Cape.
Scrophulariaceae
Authors: Steyn H. M.
Published: March 2014

Anticharis juncea, an overlooked record for South Africa, with notes on its type localities and flower morphology.
Amaryllidaceae
Authors: Snijman D. A. , Kolberg H.
Published: March 2014

Ammocharis deserticola (Amaryllideae), a new species from Namibia and a key to species of the genus.
Iridaceae
Authors: Goldblatt P. , Manning J. C.
Published: March 2014

Taxonomic notes on Moraea (Irideae) in Congo and adjacent countries.
Systematics of the southern African genus Ixia (Iridaceae: Crocoideae): 4. Revision of sect. Dichone
Authors: Goldblatt P. , Manning J. C.
Published: March 2014

The southern African genus Ixia L. comprises ± 90 species from the winter-rainfall zone of the subcontinent. Ixia sect. Dichone (Salisb. ex Baker) Goldblatt J.C.Manning, one of four sections in the genus and currently including 10 species and three varieties, is distinguished by the following floral characters: lower part of the perianth tube filiform and tightly clasping the style; filaments not decurrent; upper part of the perianth tube short to vestigial; style branches involute-tubular and stigmatic only at the tips; and so-called subdidymous anthers. We review the taxonomy of the section, providing complete descriptions and distribution maps, and a key to the species. I. amethystina Manning Goldblatt is recognized to be a later synonym of I. brevituba G.J.Lewis. Most collections currently included under that name represent another species, here described as I. rigida. We recognize five additional species in the section: early summer-blooming I. altissima from the Cedarberg; I. bifolia from the Caledon District; I. flagellaris, a stoloniferous species from the Cedarberg; I. simulans from the western Langeberg; and I. tenuis from the Piketberg. We also raise to species rank I. micrandra var. confusa and var. minor, as I. confusa and I. minor respectively. Foliar and associated floral variation in the widespread I. scillaris has led us to recognize two new subspecies among its northern populations, broad leaved subsp. latifolia and the dwarfed, smaller flowered subsp. toximontana; subsp. scillaris is restricted to the immediate southwestern Cape, from Darling to Somerset West. Sect. Dichone now has 17 species and two subspecies.
Iridaceae
Authors: Goldblatt P. , Manning J. C.
Published: March 2014

Taxonomic notes on Aristea (Aristeoideae) in tropical and eastern southern Africa.
Simulating adverse event spontaneous reporting systems as preferential attachment networks
Authors: Botsis T. , Ball R. , Scott J.
Published: March 2014

Background: Spontaneous Reporting Systems [SRS] are critical tools in the post-licensure evaluation of medical product safety. Regulatory authorities use a variety of data mining techniques to detect potential safety signals in SRS databases. Assessing the performance of such signal detection procedures requires simulated SRS databases, but simulation strategies proposed to date each have limitations.

Objective: We sought to develop a novel SRS simulation strategy based on plausible mechanisms for the growth of databases over time.

Methods: We developed a simulation strategy based on the network principle of preferential attachment. We demonstrated how this strategy can be used to create simulations based on specific databases of interest, and provided an example of using such simulations to compare signal detection thresholds for a popular data mining algorithm.

Results: The preferential attachment simulations were generally structurally similar to our targeted SRS database, although they had fewer nodes of very high degree. The approach was able to generate signal-free SRS simulations, as well as mimicking specific known true signals. Explorations of different reporting thresholds for the FDA Vaccine Adverse Event Reporting System suggested that using proportional reporting ratio [PRR] > 3.0 may yield better signal detection operating characteristics than the more commonly used PRR > 2.0 threshold.

Discussion: The network analytic approach to SRS simulation based on the principle of preferential attachment provides an attractive framework for exploring the performance of safety signal detection algorithms. This approach is potentially more principled and versatile than existing simulation approaches.

Conclusion: The utility of network-based SRS simulations needs to be further explored by evaluating other types of simulated signals with a broader range of data mining approaches, and comparing network-based simulations with other simulation strategies where applicable.

Citation: Scott J, Botsis T, Ball R. Simulating adverse event spontaneous reporting systems as preferential attachment networks: Application to the Vaccine Adverse Event Reporting System. Appl Clin Inf 2014; 5: 206–218 http://dx.doi.org/10.4338/ACI-2013-11-RA-0097
OBLIQUE MULTI-CAMERA SYSTEMS – ORIENTATION AND DENSE MATCHING ISSUES
Authors: Rupnik E. , Nex F. , Remondino F.
Published: March 2014

Abstract. The use of oblique imagery has become a standard for many civil and mapping applications, thanks to the development of airborne digital multi-camera systems, as proposed by many companies (Blomoblique, IGI, Leica, Midas, Pictometry, Vexcel/Microsoft, VisionMap, etc.). The indisputable virtue of oblique photography lies in its simplicity of interpretation and understanding for inexperienced users allowing their use of oblique images in very different applications, such as building detection and reconstruction, building structural damage classification, road land updating and administration services, etc. The paper reports an overview of the actual oblique commercial systems and presents a workflow for the automated orientation and dense matching of large image blocks. Perspectives, potentialities, pitfalls and suggestions for achieving satisfactory results are given. Tests performed on two datasets acquired with two multi-camera systems over urban areas are also reported.
A NEW RELIABLE BORESIGHT CALIBRATION METHOD FOR MOBILE LASER SCANNING APPLICATIONS
Authors: Le Scouarnec R. , Touzé T. , Lacambre J. B. , Seube N.
Published: March 2014

Abstract. This paper presents a new INS-LiDAR bore-sighting parameters calibration method that differs from traditional methods on two main aspects. First, the method is static, which avoids being affected by GPS errors and enables the extraction of scanlines. For terrestrial laser scanning, this aspect is extremely important since ranges are short and the GPS errors are the first source of error during the calibration process. Second, the method is based on a rigorous mathematical model, which allows providing reliable boresight quality factors. After presenting the boresight determination problem, this paper will introduce the existing calibration procedures. Then, it will describe the new procedure and explain how it overcomes the limitations of the traditional approaches. Finally, some results from both simulations and real datasets are presented to illustrate our approach.
Dual mode of embryonic development is highlighted by expression and function of Nasonia pair-rule genes
Authors: Rosenberg Miriam I , Brent Ava E , Payre François , Desplan Claude
Published: March 2014

Embryonic anterior–posterior patterning is well understood in Drosophila, which uses ‘long germ’ embryogenesis, in which all segments are patterned before cellularization. In contrast, most insects use ‘short germ’ embryogenesis, wherein only head and thorax are patterned in a syncytial environment while the remainder of the embryo is generated after cellularization. We use the wasp Nasonia (Nv) to address how the transition from short to long germ embryogenesis occurred. Maternal and gap gene expression in Nasonia suggest long germ embryogenesis. However, the Nasonia pair-rule genes even-skipped, odd-skipped, runt and hairy are all expressed as early blastoderm pair-rule stripes and late-forming posterior stripes. Knockdown of Nv eve, odd or h causes loss of alternate segments at the anterior and complete loss of abdominal segments. We propose that Nasonia uses a mixed mode of segmentation wherein pair-rule genes pattern the embryo in a manner resembling Drosophila at the anterior and ancestral Tribolium at the posterior.
Review of plasma-enhanced atomic layer deposition: Technical enabler of nanoscale device fabrication
Authors: Kim Hyungjun , Oh Il-Kwon
Published: March 2014

With devices being scaled down to the nanometer regime, the need for atomic thickness control with high conformality is increasing. Atomic layer deposition (ALD) is a key technology enabler of nanoscale memory and logic devices owing to its excellent conformality and thickness controllability. Plasma-enhanced ALD (PE-ALD) allows deposition at significantly lower temperatures with better film properties than in conventional thermal ALD. These benefits make PE-ALD more attractive for nanoscale device fabrication. In this paper, the basic characteristics and film properties of PE-ALD processes will be reviewed, focusing on the application of PE-ALD in key components of nanoscale device fabrication: gate oxides, Cu interconnects, and nanoscale contacts.
Relationship between center-peaked plasma density profiles and harmonic electromagnetic waves in very high frequency capacitively coupled plasma reactors
Authors: Sawada Ikuo , Ventzek Peter L. G. , Lane Barton , Ohshita Tatsuro , Upadhyay Rochan R. , Raja Laxminarayan L.
Published: March 2014

An understanding of the factors that control radial plasma uniformity in very high frequency (VHF) capacitively coupled plasma (CCP) sources is important for many plasma processes in semiconductor device manufacturing. Here, we report experimental measurements and high-resolution self-consistent numerical simulations that illustrate the plasma density profile and the higher harmonic wave content in two types of VHF-CCP test-bench reactors. A distinct sharp center peak superimposed on a broad center peak in argon plasma was observed for driving frequencies of 60 and 106 MHz. Experimental measurements and numerical simulations of the electric field power spectrum reveal the presence of UHF waves when the electron density is over 5 × 1016 (#/m3). The presence of UHF waves closely correlates with the occurrence of a distinct and sharp-center-peaked electron density. The numerical simulations show that specific frequency bands in the UHF spectrum are amplified in the plasma and lead to the evolution of the sharp-center-peaked electron density.
Real-time characteristic impedance monitoring for end-point and anomaly detection in the plasma etching process
Authors: Motomura Taisei , Kasashima Yuji , Uesugi Fumihiko , Kurita Hiroyuki , Kimura Naoya
Published: March 2014

We propose a practical and highly sensitive characteristic impedance monitoring (CIM) system for detecting the etching end point and anomalies during the plasma etching process. The CIM system employs a directional coupler and a newly developed vector processing system. The etching end point was successfully detected when a SiO2/Si wafer was etched with CF4 plasma; the system also detected wafer fluttering occurring during SF6–N2 plasma etching. The reactance component of the characteristic impedance primarily changed with the transient response of the electric potential on the inner glass surface during SF6–N2 plasma etching.
Characterization of polymer layer formation during SiO2/SiN etching by fluoro/hydrofluorocarbon plasmas
Authors: Miyake Keita , Ito Tomoko , Isobe Michiro , Karahashi Kazuhiro , Fukasawa Masanaga , Nagahata Kazunori , Tatsumi Tetsuya , Hamaguchi Satoshi
Published: March 2014

In reactive-ion etching (RIE) of silicon oxide (SiO2) or silicon nitride (SiN) by fluorocarbon (FC) or hydrofluorocarbon (HFC) plasmas, fluorinated carbon layers may be formed on the etched surfaces and affect their etching rates. In this study, the properties of SiO2 and SiN etching by FC or HFC plasmas are examined in light of the formation mechanism of such carbon layers by molecular dynamics (MD) simulation. Furthermore, in this study, the electronegativity effect of fluorine (F) is taken into account in the interatomic potential functions for C–F and Si–F bonds and MD simulations here show SiO2 and SiN sputtering yields are closer to those obtained from ion beam experiments. It has been found from MD simulations that the SiN sputtering yield during etching by HFC ions is higher than that by FC ions owning to the fact that hydrogen in the HFC ion beam tends to impede the formation of a fluorocarbon layer on SiN and therefore energetic fluorine ions/atoms are more readily available to etch SiN underneath the polymer layer.
In situ X-ray photoelectron spectroscopy study of gas cluster ion beam etching of FeCo film
Authors: Hinoura Ryo , Yamaguchi Akira , Toyoda Noriaki , Hara Ken-ichi , Yamada Isao
Published: March 2014

FeCo films of the type used in spin transfer torque magnetoresistive random access memory were etched by gas cluster ion beam (GCIB) irradiation with acetic acid vapor and characterized by in situ X-ray photoelectron spectroscopy. After 20 keV O2-GCIB irradiation with acetic acid vapor, etching depth enhancement (10.7×) was observed compared with the results without acetic acid vapor. The etching model of FeCo can be described as follows: (1) FeCo oxide formation with O2-GCIB irradiation, (2) acetic acid adsorption on FeCo oxide, (3) reactions between FeCo oxide and acetic acid, and (4) the desorption of volatile compounds by local and transient heating owing to O2-GCIB bombardment. Cross-sectional transmission electron microscopy, transmission electron diffraction analysis, and electron energy loss spectroscopy results showed no significant etching damage or oxidation of FeCo films after etching by O2-GCIB irradiation with acetic acid vapor. Therefore, the low-damage etching of FeCo can be performed by O2-GCIB irradiation with acetic acid vapor.
Micro-photoreflectance spectroscopy for microscale monitoring of plasma-induced physical damage on Si substrate
Authors: Matsuda Asahiko , Nakakubo Yoshinori , Takao Yoshinori , Eriguchi Koji , Ono Kouichi
Published: March 2014

An advanced method of photoreflectance spectroscopy (PRS) is studied to enable the microscale optical characterization of Si substrates, physically damaged by energetic ions from plasma during etching. The method examined in this study (µ-PRS) features a microscope module that focuses a probe beam into a 15-µm-wide “microspot” on the wafer surface. Silicon wafers were exposed to argon plasma and then measured by µ-PRS. The obtained spectra were analyzed, and the damaged wafers were quantitatively characterized in terms of the change in their surface potential. In this study, we demonstrate the µ-PRS’s capability for the microscopic characterization of plasma-damaged wafers.
Effects of plasma-induced charging damage on random telegraph noise in metal–oxide–semiconductor field-effect transistors with SiO2 and high-k gate dielectrics
Authors: Kamei Masayuki , Takao Yoshinori , Eriguchi Koji , Ono Kouichi
Published: March 2014

We clarified in this study how plasma-induced charging damage (PCD) affects the so-called “random telegraph noise (RTN)” — a principal concern in designing ultimately scaled large-scale integrated circuits (LSIs). Metal–oxide–semiconductor field-effect transistors (MOSFETs) with SiO2 and high-k gate dielectric were exposed to an inductively coupled plasma (ICP) with Ar gas. Drain current vs gate voltage (I
ds–V
g) characteristics were obtained before and after the ICP plasma exposure for the same device. Then, the time evolution of I
ds fluctuation defined as I
ds/μIds was measured, where μIds is the mean I
ds. This value corresponds to an RTN feature, and RTN was obtained under various gate voltages (V
g) by a customized measurement technique. We focused on the statistical distribution width of (I
ds/μIds), δ(I
ds/μIds), in order to clarify the effects of PCD on RTN. δ(I
ds/μIds) was increased by PCD for both MOSFETs with the SiO2 and high-k gate dielectrics, suggesting that RTN can be used as a measure of PCD, i.e., a distribution width increase directly indicates the presence of PCD. The dependence of δ(I
ds/μIds) on the overdrive voltage V
g–V
th, where V
th is the threshold voltage, was investigated by the present technique. It was confirmed that δ(I
ds/μIds) increased with a decrease in the overdrive voltage for MOSFETs with the SiO2 and high-k gate dielectrics. The presence of created carrier trap sites with PCD was characterized by the time constants for carrier capture and emission. The threshold voltage shift (ΔV
th) induced by PCD was also evaluated and compared with the RTN change, to correlate the RTN increase with ΔV
th induced by PCD. Although the estimated time constants exhibited complex behaviors due to the nature of trap sites created by PCD, δ(I
ds/μIds) showed a straightforward tendency in accordance with the amount of PCD. These findings provide an in-depth understanding of plasma-induced RTN characteristic changes in future MOSFETs.
Control of work function of indium tin oxide: A surface treatment by atmospheric-pressure plasma layer on fabric-type electrodes
Authors: Ueda Yoshihiko , Abe Junichi , Murata Hideyuki , Gotoh Yasuhito , Sakai Osamu
Published: March 2014

The surface electronic properties of metal oxides, which affect the performances of layered electronic devices, are controlled by non-thermal atmospheric-pressure plasmas generated using a fabric-type electrode and gas flow induced through this plasma layer. We specify a method to control the work function of indium tin oxide (ITO) films by this plasma, in which such reactive species as oxidant radicals are generated. These oxidants are spatially transported in the gas flow to the ITO surface and increase the ITO’s work function, as verified in our experimental results. To examine the effects of the increased work function in a specific electronic device, we treat the surface of an ITO electrode in an organic light-emitting diode and observe the enhancement of the light-emitting efficiency.
Extraction of time constants ratio over nine orders of magnitude for understanding random telegraph noise in metal–oxide–semiconductor field-effect transistors
Authors: Obara Toshiki , Yonezawa Akihiro , Teramoto Akinobu , Kuroda Rihito , Sugawa Shigetoshi , Ohmi Tadahiro
Published: March 2014

The random telegraph noise (RTN) characteristics in numerous metal–oxide–semiconductor field-effect transistors were evaluated accurately with small floor noise of 59 µV. Because of the small floor noise RTN characteristics with small amplitudes could be measured. The time constants: time to emission (τe) and time to capture (τc) were extracted from measurement results with sampling period of 1 µs and sampling time of 600 s, and they were distributed for over six orders of magnitude. Based on the extracted data of τe and τc, there is no correlation between

and

. Also, it was clarified that the time constant ratio (

) were distributed over nine orders of magnitude. Additionally, the gate bias dependence of

,

, and

were analyzed. The distribution of

is shifted to larger values with the increase of drain current (I
D) and that of

is shifted to smaller values with the increase of I
D.
VLSI processor with a configurable processing element array for balanced feature extraction in high-resolution images
Authors: Zhu Hongbo , Shibata Tadashi
Published: March 2014

A VLSI processor employing a configurable processing element array (PEA) is developed for a newly proposed balanced feature extraction algorithm. In the algorithm, the input image is divided into square regions and the number of features is determined by noise effect analysis in each region. Regions of different sizes are used according to the resolutions and contents of input images. Therefore, inside the PEA, processing elements are hierarchically grouped for feature extraction in regions of different sizes. A proof-of-concept chip is fabricated using a 0.18 µm CMOS technology with a 32 × 32 PEA. From measurement results, a speed of 7.5 kfps is achieved for feature extraction in 128 × 128 pixel regions when operating the chip at 45 MHz, and a speed of 55 fps is also achieved for feature extraction in 1920 × 1080 pixel images.
Ab initio calculations of polycyclic aromatic hydrocarbons adsorbed on graphite edge for molecular-scale surface coatings of lithium-ion battery anodes
Authors: Kawai Takazumi
Published: March 2014

We have investigated the atomic configurations and electronic structures of graphite edges adsorbed by polycyclic aromatic hydrocarbons, aiming for application to lithium-ion-battery anodes, where thin and robust coating layers are required for fast charge/discharge processes and long lifetime. In particular, we examined the adsorption of a perylene molecule on an edge of graphite. We considered that the edge of perylene connects two layers of graphite with σ-bonds. We found that the optimized atomic structures are stable and the planar surface of perylene is parallel to the insertion direction of lithium ions similar to the original graphite edges. Therefore, the coating does not disturb the diffusion of lithium ions during charge/discharge processes. Furthermore, there is no hybridization between the graphite edge and the perylene molecule near the Fermi level, even though they have chemical bonds between them. Thus, the electronic states of the chemisorbed perylene molecule are insensitive to the change in the electric potential of the graphite. Consequently, we expect them to suppress the electrochemical decomposition of electrolytes and solvents on the anode surface. Hence, polycyclic aromatic hydrocarbons are one of the best candidates for the coating materials of graphite anodes for realizing a higher charge/discharge rate and longer lifetime.
New Shape Flexural Mode Quartz Crystal Resonator with Suppression of Energy Leakage by Vibration
Authors: Kawashima Hirofumi , Nakazato Mitsuhiro
Published: March 2014

This paper describes a new shape flexural mode quartz crystal resonator which suppresses energy leakage by vibration. An object of this paper is to propose a new shape resonator which vibrates in a flexural mode and to clarify its frequency characteristics in the calculation and the experiments. Frequency temperature behavior, series resistance versus resonant frequency and resonant frequency versus thickness are also shown in the experiments. The present resonator is found to show excellent electrical characteristics in the frequency range of approximately 200 kHz to 450 kHz.
A New Type of Piezoelectric-Ceramic Hollow-Cylinder Torsional Vibrator
Authors: Shimizu Hiroshi , Yoshida Tetsuo
Published: March 2014

This paper presents a new structure of piezoelectric-ceramic torsional-mode vibrator. The vibrator consists of a piezoelectric-ceramic hollow-cylinder using no adhesion. On its outer cylindrical surface interdigital electrodes are located at an inclined angle of 45 degrees against the cylinder axis. The interdigital electrodes are used both for poling and for AC excitation. The capacitance ratio of about 5.8 was experimentally obtained for the fundamental torsional-mode. This torsional-mode vibrator has an advantage of much more simple construction than the conventional vibrators.
Piezoelectric Ceramic Resonator Using the Fork-Mode Vibration
Authors: Inoue Jiro , Kaida Hiroaki
Published: March 2014

A compact and easily packaged piezoelectric ceramic resonator in the kHz medium band using the fork-mode vibration has been studied. The fork-mode vibration was examined by making a slit in rectangular ceramics. Displacement and charge distribution were analyzed by the finite element method, and optimum electrode configuration was estimated. An ultra thin 200 kHz resonator was fabricated and evaluated.
Consideration of a Vibratory Gyroscope by Equivalent Mechanical Circuit
Authors: Kudo Subaru , Konno Masashi , Nakamura Kiyoshi
Published: March 2014

This paper deals with the Coriolis force on the equivalent circuits for a vibratory gyroscope used as an angular rate sensor. Coriolis force is calculated as the distributed driving force working on the elastic vibrator. The distributed Coriolis force is considered using the normal mode function of a vibrating resonator.
Frequency Modulation Device using Ultrasonic Bulk Waves
Authors: Georgiev Zdravko , Kato Terumasa , Hatta Ichiro
Published: March 2014

Frequency modulation devices were constructed with a delay line oscillator using ultrasonic bulk waves. The oscillation frequency (F
0=265 kHz) was modulated linearly in response to the amplitude of control signal. The sideband intensities of the frequency spectra were expressed in terms of the Bessel function as expected from theoretical consideration. Theoretically, the modulation index is proportional to the voltage of modulation signal divided by modulation frequency. Their ratio does not depend on the frequency and the voltage of modulation signal. The ratio was 25 V-1s-1 in the present modulation device.
Prevention of Residual Vibration of a Piezoelectric Actuator by Pulse Driving
Authors: Kusakabe Chiharu , Tomikawa Yoshiro , Takano Takehiro , Narita Kenetsu
Published: March 2014

This paper deals with an electrical prevention method using pulse voltage for residual vibration of a piezoelectric actuator.
The rapid stopping of the residual mechanical vibration of a piezoelectric actuator is made possible by setting the pulse width, amplitude and impressed time of a control pulse.
The effect of this method is confirmed here both by simulation using the equivalent circuit and by experiment using a cantilever type piezoelectric actuator.
Study on Transformer Ratio and Capacitance in Equivalent Circuit Model for SAW Transducer
Authors: Shiba Takashi , Yamada Jun , Toyama Tatsuro
Published: March 2014

The transformer ratio and capacitance in an equivalent circuit for an interdigital surface acoustic wave (SAW) transducer are proposed in general form The relation between these parameters and the input admittance for one periodic section of the equivalent circuit is calculated. Then, using calculated values for admittance by H. Engan, the parameters are finally determined as a function of metallized ratio, harmonic number and material-constants. The results are verified by experiments.
Estimation of Elastic Constants, Mass Density and Thickness of Thin Films from SAW Velocity Dispersion
Authors: Watanabe Yoshihiro , Hashimoto Ken-ya , Yamaguchi Masatsune
Published: March 2014

The paper describes a method of estimating the elastic constants, mass density and thickness of a thin film fabricated on a substrate. The method is substantially based on fitting simplified theoretical SAW velocity dispersion to experimental dispersion data by non-linear least squares. The result has shown that when the film thickness is large, or when the film thickness or the longitudinal wave velocity is known, other material constants can be estimated without much difficulty.
Site of Electron Acoustic Signal Generation from Junction of an npn Si Transistor-Chip under Bias Application
Authors: Takenoshita Hiroshi , Kobayashi Mutsuo
Published: March 2014

The junction between the base and collector of an npn Si transistor-chip was exposed to a microscopic field by angle lapping. Bias voltage applied to the chip was varied and examined by SEM and electron-acoustic microscopy with these results: (1) The site of electron acoustic (EA) signal generation stays unchanged under varying bias conditions. (2) The site of EA signal generation was almost the same as the position of the junction. (3) The EA and electron beam induced current signals closely correspond but are distinctly different. The mechanism of EA signal generation is suggested and discussed.
Welding Characteristics of Thin Copper Wire Using Complex Vibration Ultrasonic Wire Bonding Systems
Authors: Tsujino Jiromaru , Murayama Yoshihiro , Furuya Hiroshi
Published: March 2014

Welding characteristics of thin copper wire using complex vibration ultrasonic wire bonding are studied. The welding systems used have a complex transverse vibration welding tip which is driven by two longitudinal vibration systems crossed at a right angle. Welding tip vibration locus shape is controlled by regulating these vibration systems. Welding specimens used are 0.025 mm diameter copper wire and 1.0 mm thick copper plate. These specimens are welded successfully with smaller vibration amplitude and shorter weld time than a conventional welding system. Weld strength is independent of specimen wire direction.
Ultrasonic Motors Using Longitudinal and Torsional Modes of a Rod Vibrator
Authors: Tomikawa Yoshiro , Adachi Kazunari , Aoyagi Manabu , Sagae Tadaatsu , Takano Takehiro
Published: March 2014

Ultrasonic motors using longitudinal and torsional modes of a rod vibrator were studied. Some forms of the motor construction are proposed herein, and the operational principles are described together with the measured characteristics. The motors dealt with are expected to have practical application when further improved.
An Open Acoustic-Tube Method for Measuring Sound Velocity and Attenuation Constant of Marine Sediments
Authors: Kimura Masao , Snimizu Hiroshi
Published: March 2014

This paper describes a new method using an open acoustic-tube for in situ measurement of the sound velocity and the attenuation constant of marine sediments. The usefulness of the method is shown through basic experiments at about 3 kHz on a sediment model. A bimorph type piston transducer, resonating at a low frequency in spite of its small size, was devised for use in the experiments.
Evaluation of the Fixation of Artificial Hip Joint by Acoustic Emission
Authors: Gao Xiao-Jie , Murota Kagehisa , Tomita Yoshitsugu , Ono Makoto , Higo Yakichi , Nunomura Shigetomo
Published: March 2014

The fixation between an artificial joint and the bone becomes loose with time. To avoid this loosening, and there by increase the life of the artificial joint, it is important to detect the loosening at a very early stage. In this paper, we tried to detect the loosening of an artificial hip joint by recognizing analyzing acoustic emission from it. More than 200 measurements were taken and it is clear that the AE method is very efficient and sensitive for evaluation of the fixation condition of an artificial joint.
Measurement of Actual Vehicle Speed Using Ultrasonic Doppler Effect
Authors: Nakamura Hiroyuki , Okazaki Toshimi , Tsuji Yorikazu , Okada Seiji
Published: March 2014

We studied a means to determine actual vehicle speed using the Doppler effect of the ultrasonic wave. In this paper, we report the effect of the frequencies of ultrasonic waves on the intensity ratio and the detecting errors of the reflected waves. From our result, it is clear that ultrasonic waves with a frequency of 200 kHz are applicable to determine an actual speed within a practical precision of 5% in the range of 0 to 50 km/h.
Basic Study of Acoustic Imaging Using Encoding Aperture Receiver with Piezoelectric Polymer Transducer
Authors: Koyama Kiyohito , Ito Hiroshi , Tanaka Katsufumi , Tamura Yasutaka
Published: March 2014

Basic studies have been carried out on an ultrasonic camera which can make an image with one signal channel without mechanical and electrical scanning. Experiments were performed to investigate the effectiveness of the encoding aperture receiver system and the pseudo-inverse detection method. The latter method worked quite well for the two dimensional image for a single target. The limitation of the system is discussed in respect to the imaging process and transducer materials.
Measurements of Acoustic Properties of Teeth by Impulsive-Wave Acoustic Microscope System
Authors: Ha Kang-lyeol , Sannomiya Toshio , Kushibiki Jun-ichi , Chubachi Noriyoshi
Published: March 2014

A spectral analysis method was introduced into an impulsive-wave SAM system to measure the spatial variation of acoustic properties in hard dental tissues. Longitudinal velocity was determined from the frequency intervals of maxima (or minima) in the total power spectrum of two separated short pulses reflected from the surface and the bottom of a sliced specimen. The attenuation coefficient was further determined by the difference of the power spectra of the above two pulses. It has been found that the velocity and the attenuation coefficient vary considerably with depth of the tooth in the enamel and dentine.
Integrated Optic Matrix-Vector Multipliers Using Acousto-Optic Bragg Diffraction
Authors: Goto Nobuo , Kanayama Yukihiro , Miyazaki Yasumitsu
Published: March 2014

An integrated optic numerical processor performing matrix-vector multiplication in analog representation is proposed. Parallel processing of a number of numerical products is operated in the same area of a substrate by means of multiple Bragg diffraction of multi-wavelength optical signals caused by multi-frequency surface acoustic waves. The wavelength interval of multiplexed optical signals can be 0.77 nm for the optical beam width of 3 mm and the acoustic frequency of 1 GHz.
Characteristics of Integrated Optical Devices Using Magnetostatic Surface Waves
Authors: Hasegawa Kazuo , Miyazaki Yasumitsu
Published: March 2014

Optical mode conversion induced by magnetostatic surface waves (MSSWs) has great potential in optical signal processing devices. MSSW devices can be used at much higher signal frequencies than surface acoustic wave (SAW) devices. In an optical mode conversion experiment using bismuth substituted yttrium iron garnet (BiYIG) waveguide, a change of 3.35% over the interaction length l of 4.5 mm was observed at a microwave signal frequency f
m of 2.16 GHz with a magnetic field H
0 set at 270 Oe.
Ultrasonic Measurement on the Single Crystal La2(1-x)Sr2xCuC4
Authors: Yamaguchi Mitsushiro , Suzuki Masaru , Okuda Yuichi , Hidaka Yoshikazu , Murakami Toshiaki
Published: March 2014

Ultrasonic measurement of the single crystal La2(1-x)Sr2x
CuO4 (x=0.06) was performed from 4.2 K to 300 K with emphasis on the anomalies near the superconducting transition T
c of 11 K and the structural phase transition T
d of 250 K. A longitudinal wave was propagated parallel to the Cu–O plane. On cooling from room temperature down to the structural phase transition temperature, the sound velocity decreased gradually. A large discontinuity of sound velocity from 5.1×103 m/sec to 3.2 i
m
e
s103 m/sec was observed just at the structural phase transition. The discontinuity of sound velocity at T
c was not found within the present resolution of Δ
V/V∼5×10-6.
Study of Scanning Photoacoustic Microscopy
Authors: Tokunaga Yoshiaki , Minamide Akiyuki , Tamura Keimei , Teraoka Sad
Published: March 2014

The hardware and software of Scanning Photoacoustic Microscope (SPAM) composed of low price parts are described. From the obtained images it is found that our SPAM can be used well to understand fundamental characteristics of a surface flaw on a machinable ceramic, surface and subsurface flaws in epoxy and the distribution of carbon fiber in the CFRP (Carbon Fiber Reinforced Plastic) as an equipment of nondestructive testing.
Measurements of SAW Velocity Using an Ultrasonic-Micro Spectrometer
Authors: Ohira Katsumi , Tsukahara Yusuke
Published: March 2014

An ultrasonic micro-spectrometer to measure the spectra at a small surface area by focusing the ultrasonic wave is described. In this system, a sensor unit consists of a transmitter with a spherical lens and a receiver with a planar lens. The former converges the ultrasonic wave to achieve a high spatial resolution and the latter receives specific angular components from a reflected wave. Acoustic images obtained by scanning a printed wiring board with this sensor show a high spatial resolution with burst waves. The phase velocities of surface acoustic waves which were excited on solids were measured by impulsive waves.
Ultrasonic Studies of Polymer Solutions
Authors: Nomura Hiroyasu , Koda Shinobu
Published: March 2014

Recent works on the equilibrium and dynamic properties of polymer solutions obtained from ultrasonic measurements were reviewed. The dissolved states of polymer in solutions, the amount of solvated solvent and hydrated water, and the degree of counterion binding of polyelectrolytes were discussed on the basis of the sound velocity measurement at a few MHz. The ultrasonic relaxation processes in the frequency range from several hundred kHz to a few hundred MHz were interpreted by the local segmental motion of polymer in solution. The ultrasonic degradation of polysaccharides in solutions is briefly discussed.
Ultrasonic Attenuation in Single Crystals of Mn-Ferrite
Authors: Kawai Yoriyoshi
Published: March 2014

The acoustic losses in single crystals of Mn-ferrite (Mn
x
Fe3-x
O4; x=1.1, 1.0 and 0.82) have been studied in the temperature range of 180–650 K by applying longitudinal vibrations of 150 kHz. Loss peaks were observed at 232 and 537 K with activation energies of 0.3 and 0.8 eV, respectively. The first peak was regarded as a stress-induced relaxation of electrons between Fe2+ and Mn3+ ions on octahedral sites in Mn-rich ferrites. The second peak was ascribed to the exchange motion of cations and vacancies on octahedral sites. Both peaks were observed only along the <111> or <110> direction, and were affected by heat treatments received in the temperature range of 300–600°C.
Measurement of Vibrational Current by Charged Dislocation in NaCl Crystal
Authors: Tateno Hiroto , Arima Kazushi , Fukai Akira , Iwashita Youichirou
Published: March 2014

To study the structure of the core of an edge dislocation in ionic crystal, we measured the amplitude dependence of internal friction by automated Marx's composite oscillator method and the vibrational current caused by charged dislocations. The phase angle between vibrational current and strain suddenly changed by 180 degrees at a strain amplitude of 10-6. From this fact we discuss the structure of the dislocation core.
Receiving Characteristics of Piezo-Rubber Transducers
Authors: Ogura Kohji , Ohya Kanji , Banno Hisao
Published: March 2014

Acoustic and piezoelectric properties of Piezo-Rubbers and receiving characteristics of Piezo-Rubber transducers are reported as a function of PbTiO3 volume fraction. Piezo-Rubber is a piezoelectric composite material consisting of PbTiO3 and chloroprene rubber. The frequency dependence of underwater receiving sensitivity, directional patterns and acoustic transmitting/receiving responses of Piezo-Rubber transducers are measured, and the results discussed in terms of the piezoelectric properties of Piezo-Rubbers and PZT materials. In addition, the correlation between the value of d31 of Piezo-Rubber and lateral vibrational noise is discussed.
A Design Method for Tonpilz Piezoelectric Underwater Transducer
Authors: Inoue Takeshi , Sasaki Takashi , Sugiuchi Katsumi , Hattori Akiko
Published: March 2014

To synthesize a Tonpilz piezoelectric underwater transducer, two simple and expedient equivalent circuit models of the transducer are presented. The shapes and dimensions for each quarter wavelength model, which can operate in a required resonant frequency, were calculated. Moreover, using a half wavelength approximation model combined with the quarter wavelength models, transmitting voltage sensitivity and receiving voltage sensitivity were calculated. Also, comparisons between the calculation result obtained by this model, the calculation result determined by precise equivalent circuit analysis and the actually measured result are discussed.
A Dummy Load for Performance Test of Sonar Transducer
Authors: Iida Haruhisa , Kurosawa Minoru , Ueha Sadayuki , Saito Yukio
Published: March 2014

A dummy load transducer with an electrical termination was used to test the performance of a sonar transducer in air. The dummy load transducer was mechanically attached to the sonar transducer and loaded with the same mechanical impedance which would be loaded underwater. The mechanical impedance was calculated using a 4-port equivalent circuit of the dummy transducer and adjusted by changing the electrical termination. Transmitting sensitivity and other characteristics were successfully measured with this dummy load in the frequency range from 6.5 kHz to 7.5 kHz.
Analysis of Acoustic Wave Propagating in Bilinear Surface Duct by Hybrid Ray-Parabolic Equation Method
Authors: Kaminishi Yoshiaki , Ohshima Kohji , Ishihara Toyohiko
Published: March 2014

The systematic procedure of acoustic wave propagation in a bilinear surface duct is described. When both source and observation points are placed in the boundary layer, the acoustic ray theory fails because those rays which have undergone too many reflections at the sea surface interfere with one another. It is shown how the wave solution in the boundary layer can be found by solving the parabolic equation (PE). Using these solutions as initial inputs to the PE code, it is confirmed by comparison with the reference solution that the resulting hybrid ray-PE algorithm predicts the wave fields accurately.
Theoretical Study of Ultrasonic Wave Propagation by Quasi-Geometrical Acoustics –Interference Effect–
Authors: Sugiyama Masaru
Published: March 2014

A method of quasi-geometrical acoustics which is believed to be applicable to the analysis of ultrasonic wave propagation is reviewed briefly. The example of interference phenomena in an elastic solid near a melting point is studied and seems to be interesting in itself from the viewpoint of high-temperature materials science.
Relation between Active Sound Absorption and Mutual Radiation Resistance of an Array of Piston Transducers in Water
Authors: Hasegawa Akio , Hoshiyama Ryoichi , Kikuchi Toshiaki , Takahashi Sumio , Nakanishi Toshiyuki
Published: March 2014

Sound absorption due to acoustic interaction between transducers arranged in water, that is, an active sound absorption is described. The mutual radiation resistance is calculated for two identical square piston transducers vibrating in an infinite rigid plane, and its effect on sound absorption is made clear. The calculated reduction in radiation power is about -16 dB in a three-transducer system with relative velocities 1, -1.7, and 1. Acoustic intensity field maps are drawn to visualize the behavior of active sound absorption. The negative intensity vector was observed experimentally.
Radiation Pattern of Acoustical Array Antenna on Concave Boundary
Authors: Kaminishi Yoshiaki , Ohta Seigoh , Ishihara Toyohiko
Published: March 2014

Acoustical radiation fields excited on a cylindrical concave boundary by an array source on the boundary are represented by either whispering gallery (WG) mode series or hybrid acoustic ray and lowest-order WG mode. The influence of the concave boundary on the radiation pattern is clarified, and the relation of the beams respectively constituted by the rays and the specific WG modes is investigated, based on numerical calculations from an analytically derived formula. The distortion of a main beam by the obstacle in the concave boundary is examined numerically by superposing only the specific WG modes.
Silicon Micromachined Vacuum Gauge Using ZnO Thin Film
Authors: Matsunaka Toshiyuki , Kihara Taizo
Published: March 2014

A bending vibrating-type pressure sensor combining ZnO piezoelectric thin film and a minute technique was constructed. The pressure dependency of the admittance characteristics and the resonance frequency of the sensor in the range of atmospheric pressure to 10-5 Torr were measured.
Sound Velocity and Attenuation Constant of High Porosity Marine Sediments
Authors: Kimura Masao
Published: March 2014

In this study, we obtain the sound velocity and the attenuation constant of high porosity marine sediments using Biot's theory and Yamamoto's modified equations, and investigate the effect of the grain size and grain size distribution on the frequency characteristics. Next, we show that the experimental values of the attenuation constant of Black sediment measured by Hampton nearly agree with the calculated values.