bluuebunny/crossref_metadata_2025 huggingface dataset:
Design Review & Preliminary Testing for a Biomimetic Absorbable Ligament Anchor
Authors: Liyanage Sandeep , Boughton Philip , Roger G. , Hyvarinen Jari , Ruys Andrew John
Published: December 2009

Review of current Anterior Cruciate Ligament (ACL) anchor technologies indicates that many devices facilitate osteointegration but not soft tissue in-growth. The design and preliminary testing of a novel biomimetic in-situ dilating bioabsorbable ACL anchor for simultaneous soft and hard tissue attachment is the subject of this study. The anchor method for this concept has been developed to mimic the mechanical-key configuration observed in a hair root. Reviewed anchor devices are typically interference screw-based. Screw anchors can lead to unnecessary ligament pre-stress, tearing during deployment and poor graft-bone contact. This work demonstrates a new fixation concept specifically developed for use with devices consisting of temperature-sensitive glass-reinforced-glass (GRG) soft tissue conductive biomaterial. Ligament anchorage is accomplished by dilation of the device into the base of a hair-root shaped osteotomy where a ligament with a collar and self tightening knot is inserted beforehand. This method facilitates full ligament-to-bone contact at the osteotomy zone where critical physiological ligament anchorage develops. Ligament pull-out loads equivalent to published results for conventional anchors were achieved using graft analogue. Testing with porcine ligaments resulted in a substantial reduction in ligament pull-out loads. Tibia bone sample constraints combined with the unraveling of the ligament knot were identified as primary factors for low pull-out loads for the porcine ligament tests. Subsequent design iterations will employ a reduction in prototype dimensions in addition to the use of a suture to lock the ligament knot. The hair-root shaped osteotomy and ligament anchor knot elements of this approach may be translated to other fixation systems and methods. By improving macro-mechanical-key interaction between the anchor, bone and ligament, further increase in pull-out forces may be achieved without unnecessary ligament pre-stress and tear damage caused by conventional interference screw threads.
Resistance Changes of (La, Sr)MnO3 Thin Film via Exchange Bias Tuning by the Application of an External Electric Field
Authors: Yokota Takeshi , Murata Shotaro , Kito Shinya , Gomi Manabu
Published: December 2009

We have investigated the relationships between the electric field-induced resistance change and the strength of the exchange interaction of the Cr2O3/ La0.7Sr0.3MnO3 (LSMO) magnetic hetero system. The hetero system subjected to field cooling (FC) showed a positive shift in the magnetization curves due to an exchange bias. The exchange bias field changed depending on the FC field. Resulting from the exchange behaviors, the resistance of LSMO film was changed by the application of an electric field to the Cr2O3 gate. This resistance change is more likely due to the interface interaction strength between the Cr2O3 and LSMO film
Effect of Stacking Layers on the Structure and Properties of Ca(Mg1/3Nb2/3)O3 / CaTiO3 Thin Films
Authors: Zhou Jing , Zhu Jie , Chen Wen , Shen Jie , Lei Qiong , He Hui Min
Published: December 2009

Effect of stacking layers on the structure and properties of Ca(Mg1/3Nb2/3)O3/CaTiO3 (CMN/CT) microwave dielectric heterogeneous thin films prepared was investigated. Precursor solutions for CMN and CT synthesis were obtained by Pechini method. The arrangement pattern has affected structure and properties of heterogeneous thin film. The CMN-CT arrangement heterostructure thin film has second phase from the CMN films layer. The CT-CMN heterostructure film which has a smooth and dense microstructure was composed of pure perovskite phase without any second phase, this result was attributed to the CT film layer which is a buffer layer between substrate and CMN film layer. At 1MHz frequency, CT-CMN exhibits the dielectric properties of εr=47.5, tanδ=0.020.
Dielectric Properties of Pb1-xBaxZrO3 Thin Films with Higher Barium Content
Authors: Hao Xi Hong , Zhai Ji Wei
Published: December 2009

The dc bias and temperature dependence of dielectric properties of Pb1-xBaxZrO3 (PBZ) thin films with higher x (x=0.6, 0.7, 0.8 and 1) were investigated in detail. The results indicated that Pb0.4Ba0.6ZrO3 films possessed a moderate tunability of 32.3% and a higher figure of merit of 53.8, which were measured at 100 kHz and at room temperature. Moreover, Pb0.4Ba0.6ZrO3 films exhibited a smaller temperature coefficient of capacitance TCC-20-90= -1390 ppm/oC.
Investigation of Oxygen Vacancies in Micro-Patterned PZT Thin Films Using Raman Spectroscopy
Authors: Nishida Ken , Osada Minoru , Yokoyama Shintaro , Kamo Takafumi , Fujisawa Takashi , Saito Keisuke , Funakubo Hiroshi , Katoda Takashi , Yamamoto Takashi
Published: December 2009

Micro-patterned Pb(Zr,Ti)O3 (PZT) films with dot-pattern were grown by metal organic chemical vapor phase deposition (MOCVD). Micro-patterned Pb(Zr,Ti)O3 (PZT) films were formed on dot-patterned SrRuO3 (SRO) buffer layer that was prepared by MOCVD through the metal mask on (111)Pt/Ti/SiO2/Si substrate. The orientation of dot-patterned PZT films was ascertained by the micro-beam x-ray diffraction (XRD) and their crystallinity was characterized by Raman spectroscopy. It was found that PZT films were oriented to (111) on dot-pattern, while (100)/(001) out of dot-pattern and the amount of oxygen vacancies at the circumference of the dot-pattern were larger than that of center of dot-pattern.
Growth and Electrical Properties of PbMg0.047Nb0.095Zr0.416Ti0.442O3 Films Fabricated by Metalorganic Decomposition
Authors: Hasegawa Yuki , Kobune Masafumi , Daiko Yusuke , Mineshige Atsushi , Yazawa Tetsuo , Fujisawa Hironori , Shimizu Masaru , Tsukada Mineharu , Yamaguchi Hideshi , Honda Koichiro
Published: December 2009

On the basis of experimental data on the piezoelectric pinpoint composition of ceramics of the ternary system Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 (PMNZT), which we investigated in our previous report, epitaxial PbMg0.047Nb0.095Zr0.416Ti0.442O3 thick films with thicknesses ranging from 0.4 to 1.9 m were fabricated on Pt(100)/MgO(100) substrates by metalorganic decomposition. The film- thickness dependence on the structural and electrical properties (dielectric, piezoelectric and ferroelectric properties) was investigated. All PMNZT films exhibited a highly uniform (001) orientation, regardless of the film thickness. The cross-sectional transmission electron microscope micrographs and all the physical data suggest that high-density PMNZT thick films with a thickness  1.0 m can be expected to function as highly electrically insulating capacitors with high potential for piezo- and ferroelectric applications.
Preparation and Characterization of Silica Film on PBT Substrate by Sol-Gel Method Using Perhydropolysilazane
Authors: Horikawa Hajime , Ogihara Takashi , Shimomura Akio , Shimomura Junko
Published: December 2009

Silica, silica/polymethylmethacrylate (PMMA) hybrid, and silica-particle blend silica films were successfully prepared on polybutylene terephtalate (PBT) substrate by dip coating using perhydropolysilazane (PHPS) as a silica source. The effect of thermal treatment on conversion from PHPS to silica was investigated in detail by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical properties of silica and silica/PMMA hybrid thin films also were examined by the pencil scratch hardness tests.
Study on Improvement of Oxidation-Resistant Capability of Metal-Silicide Thin Film and Application to Heater
Authors: Hayashi Teppei , Satoh Masashi , Yoshikado Shinzo
Published: December 2009

Thin films of Si-added-MoSi2 were deposited on Si3N4 or alumina substrate using an RF magnetron sputtering with a target made of MoSi2 and Si powders. The thin film consisted of a mixture of Si and MoSi2. The resistance of MoSi2-thin-film heaters fabricated using Si3N4 substrate heated for a long time in air increased with increasing heating-time at temperatures near 420°C due to generation of MoO3, which is an insulator, in thin film due to the oxidation of Mo in MoSi2. On the other hand, oxidation-resistant capability of thin-film heater fabricated by adding Si to MoSi2 was drastically improved compared with MoSi2 thin-film heater, because Si particles or the Si layer on a MoSi2 particle prevented the oxidation of MoSi2. The oxidation-resistant capability was excellent in air at high temperatures near 480°C for a long heating-time exceeding 950h.
Preparation of Thin Films of TiO2-Nanoparticles Using Electrophoresis Deposition Method
Authors: Ito Kazuatsu , Sato Yuuki , Adachi Motonari , Yoshikado Shinzo
Published: December 2009

TiO2-nanoparticles of anatase-type were synthesized and deposited using the electrophoresis depo-sition method. All of TiO2-nanoparticles were positively charged in colloidal aqueous solution and were attracted toward ITO glass as the negative electrode as same as nanoparticles (P25) whose diameter is larger than that of TiO2-nanoparticles. Many of the TiO2-nanoparticles were connected with each other and formed clusters, although single TiO2-nanoparticles were also observed. The cracks generated in the thin film with increasing the deposition time and thin film was flaked off from substrate. High optical transparency TiO2-nanoparticles-thin film without cracks was deposited when the deposition time was short. Moreover, the thickness of TiO2-thin film, which has high optical transparency and no cracks, could be increased using mixture of TiO2-nanoparticles and P25.
Fabrication and Characterization of Perovskite SrZrO3 Ceramics through a Combustion Technique
Authors: Thongtha Atthakorn , Bongkarn Theerachai
Published: December 2009

Perovskite SrZrO3 ceramics were successfully prepared via a combustion technique. The effect of calcination temperatures (900-1400oC) and sintering temperatures (1400-1650oC) on phase and morphology evolution of perovskite SrZrO3 ceramics were studied. The highest purity of perovskite phase powder was obtained at 1250 oC and the purity of the perovskite phase of SrZrO3 ceramics were detected in the samples sintered at 1550 oC for 6 h. The SEM results showed the average particle size (84-214 nm) and the average grain size (0.35-2.09 µm) of samples increased with the increase of firing temperatures. The shrinkage of the ceramics increased as the sintering temperatures increased. The maximum density was ~98.4% of the theoretical density for the sample sintered at 1550 oC for 6 h.
Effects of Iron Addition on Aging Behavior of Barium Titanate Ceramics under Compressive Stress
Authors: Tangsritrakul Jirapa , Unruan Muangjai , Ketsuwan Piyachon , Triamnak Narit , Rujirawat Saroj , Dechakupt Tanawadee , Ananta Supon , Yimnirun Rattikorn
Published: December 2009

In this study, a room temperature aging behavior of Ba(Ti0.99Fe0.01)O3 was investigated. It was found that the dielectric constant decreased with time and ferroelectric P-E hysteresis loops became constricted loops after aging. Moreover, the room temperature aging behavior under various stresses was also observed. It was found that the relative changes of dielectric constant with time of Ba(Ti0.99Fe0.01)O3 ceramics under stress were lower than those under the stress-free condition. For P-E hysteresis loop measurement, it can be observed that P-E hysteresis loop of Ba(Ti0.99Fe0.01)O3 ceramics became constricted loops and remanant polarizations (Pr), saturated polarizations (Ps) were decreased after aging under all stress levels. These results suggested that the applied stress may partly clamp the domain wall motion, and altered the aging behavior of the ceramics.
Dielectric Properties of Bi0.2K0.8(Zn0.1Ti0.1)Ta0.8O3 Ceramics
Authors: Ketsuwan Piyachon , Prasatkhetragarn Anurak , Ananta Supon , Huang Chien Chih , Cann David P. , Yimnirun Rattikorn
Published: December 2009

The Bi0.2K0.8(Zn0.1Ti0.1)Ta0.8O3 and Li doped ceramics prepared via the solid-state reaction technique were investigated. The XRD patterns show the single phase cubic perovskite structure without any evidence of secondary phases when sintered at 1250 oC for undoped Bi0.2K0.8(Zn0.1Ti0.1)Ta0.8O3 and sintered at 1100 oC for Li doped one. The dielectric properties indicate the diffused phase transition (DPT). The dielectric loss of undoped ceramic increases with increasing frequency in temperature range 270 oC down to -150 oC, which suggests low temperature relaxation, while the dielectric loss of Li doped ceramic reveals the interesting lower value over a wide temperature range of about 0 - 300 oC.
Wide Range Dielectric Spectroscopy of Barium Strontium Titanate Ceramics
Authors: Teranishi Takashi , Hoshina Takuya , Takeda Hiroaki , Tsurumi Takaaki
Published: December 2009

Wide band dielectric spectroscopy was applied from kHz to THz region for the analysis of both the ionic and the dipole polarization in Ba0.6Sr0.4TiO3 ceramics. The dielectric permittivity above the dielectric maximum temperature (Tm) is mostly dominated by the ionic polarization, while that below Tm is governed by the dipole polarization. Dielectric permittivity given by the dipole polarization increased and the relaxation frequency decreased with decreasing temperature. These phenomena are related to a increase of the size of polar nanoregions (PNRs).
Behavior of Hydrogen Atoms in Perovskite-Type Oxide Thin Films under Electric Fields
Authors: Morito Kentaro , Suzuki Toshimasa , Mizuno Youichi , Sakaguchi Isao , Ohashi Naoki , Matsumoto Kenji , Haneda Hajime
Published: December 2009

The behavior of hydrogen in (Ba,Sr)TiO3 (BST) thin film capacitors under electric fields was investigated by performing secondary ion mass spectroscopy (SIMS) analyses. It was clearly observed that the ingress of atmospheric hydrogen into BST thin film capacitors occurred through the anode and that it diffused toward the cathode under electric fields. In addition, it was found that the deterioration of the I-V properties of the BST thin film capacitors can be interpreted in terms of the distribution of hydrogen concentration in the BST thin films.
The Effects of Sintering Temperature Variations on some Physical Properties of Al2O3-SiO2-PbO-MgO Laminated Tape System
Authors: Alias Rosidah , Azmi Ibrahim , Shapee Sabrina Mohd , Ambak Zulkifli , Yusoff Zulfadli Mohamed , Saad Muhammad Redzuan , Mahmood Che Seman , Ahmad Megat Harun Al Rashid Megat
Published: December 2009

An Al2O3-SiO2-PbO-MgO laminated tape system was prepared to investigate the dependence of some physical properties on various sintering temperatures, 840 °C, 880 °C, 920 °C and 960 °C. The results show that the effect of the increasing sintering temperatures was a fluctuating in the density value of the laminates. It was also observed that the dielectric constant and dielectric loss showed the lowest value for the sintering temperature of 880 °C. SEM micrographs of the laminate samples shows a mixture of grain sizes and the samples had a combination of small and large pores with the average grain size around 2.20-2.64 m.
Phase Transition and Structural Analysis of (Li,Na,K)NbO3 Lead-Free Piezoelectric Ceramics
Authors: Kakimoto Kenichi , Hotta Tatsuro , Ohsato Hitoshi
Published: December 2009

Structural characterization of various (Li,Na,K)NbO3 solid solutions with different Li contents has been carried out by temperature-variable Raman scattering measurement. It was found that there was no clear thermal hysteresis between orthorhombic-tetragonal phase transition in the heating/cooling processes for (Li,Na,K)NbO3 ceramics with Li content of 6 wt% and above, although a noticeable thermal hysteresis is observed in the Raman spectra and dielectric constant measurement for the other specimens with lower Li contents. It is presumed that the structural change of (Li,Na,K)NbO3 cell tends to become insensibility against temperature as the Li content increases above 6.0 mol%.
The Effect of Rare Earth (Ln = Gd, Dy, Y and Yb) Doping on the Microstructure and Reliability in BaTiO3-Based Monolithic Ceramic Capacitors (MLCs)
Authors: Okamatsu Toshihiro , Nishimura Hitoshi , Inoue Noriyuki , Sano Harunobu , Takagi Hiroshi
Published: December 2009

The effect of rare earth (Ln = Gd, Dy, Y and Yb) and Mg ions on the microstructure and reliability of BaTiO3-based monolithic ceramic capacitors (MLCs) with Ni electrodes was investigated. The X-ray diffraction results about the lattice volume of sintered specimens suggested that Gd and Dy ions predominatly substituted into the Ba-site, Yb ions gave exclusive substitution at the Ti-site, while Y ions occupied either the Ba- and Ti-site. The reliability of ceramic capacitors was increasing with increasing the ionic radius of the rare earths in this study. The nonlinearity coefficient() etsimated from the leakage currents and the lifetime measured from the highly accelerated lifetime testing (HALT) showed a negative correlation which was observed only from Dy and Y ions doped specimens. The quantity of Ln and Mg in the grains tended to increase with increasing the Ln ionic radius. In order to improve the reliability and the insulation property of BaTiO3 based MLCs with Ni electrodes, it is important that acceptor ions at the Ti-site compensate donor ions which are rare earth ions at the Ba-site, so the overall quantity of the dopants required for the charge compensation with acceptor and donor ions increases accordingly.
Upgrade Mechanoluminescence by Sr2+ Substitution in CaAl2Si2O8: Eu2+
Authors: Zhang Lin , Xu Chao Nan , Yamada Hiroshi , Bu Nan
Published: December 2009

Recently we demonstrated that CaAl2Si2O8: Eu2+ showed novel strong mechanoluminescence (ML). In order to improve the mechanoluminescence intensity, we partly substituted the Ca2+ ions by Sr2+ ions. It was found that the ML intensity was enhanced about three times as great as the one of CaAl2Si2O8: Eu2+ by substituting 40% of Ca2+ ions to Sr2+ ions. Furthermore it was revealed that the main peaks in XRD pattern shifted to lower angle side and the emission peak shifted to a short wavelength from 428 to 418 nm, indicating that the substitution resulted in the cell volume expansion and the change of luminescent color. Based on the results of thermoluminescence and electroluminescence measurements, the possible mechanisms for the improvement of ML intensity were proposed.
V2O5 Nanotubes Novel Gas Sensor with High Sensitivity for Ethanol
Authors: Jin Wei , Chen Wen , Dong Bai Tao , Zhao Chun Xia , Mai Li Qiang , Dai Ying
Published: December 2009

Vanadium oxide nanotubes were synthesized via a rheological self-assembling process followed by a hydrothermal reaction. V2O5 gas sensors were fabricated from vanadium oxide nanotubess with an average diameter of around 90 nm and their gas-sensing properties were investigated. It was found that the sensors based on vanadium oxide nanotubes exhibit high responses ethanol gas at 270°C. The results indicate that vanadium oxide nanotube sensors will be promising candidates for practical detectors for ethanol.
Phase Diagram and Microstructure Analysis of Barium Titanate – Potassium Niobate System Piezoelectric Ceramics
Authors: Wada Satoshi , Nitta Momoyo , Kumada Nobuhiro , Tanaka Daisuke , Furakawa Masahito , Moriyoshi Chikako , Kuroiwa Yoshihiro
Published: December 2009

Barium titanate (BaTiO3, BT) and potassium niobate (KNbO3, KN) ceramics were prepared by normal sintering process. Phase diagram of BT-KN system was investigated using high-temperature XRD and dielectric measurement, and two phases coexistence between tetragonal and orthorhombic was observed at room temperature. Transmission electron microscope (TEM) observation confirmed that the microstructure of the ceramics with KN contents below 30 molar% was composed of only tetragonal BT-rich grain, while those with KN contents above 40 molar% were composed of two kinds of grains, i.e., tetragonal BT-rich and orthorhombic KN-rich grains. Phase boundary between two phases for BT-KN ceramics was grain boundary. Thus, we named two phases coexistence region for BT-KN ceramics “wide-band morphotropic phase boundary (MPB)”. Finally, dielectric and piezoelectric properties were investigated, and both dielectric and apparent d33 maximum were observed at the 0.5BT-0.5KN ceramics.
Synthesis and Luminescence Properties of Non-Doped Long Persistent Phosphors : Mg2SnO4
Authors: Torisaka Akiko , Kaneko Hiroaki , Nomizu Kentaro , Abe Sho , Ishigaki Tadashi , Toda Kenji , Uematsu Kazuyoshi , Sato Mineo
Published: December 2009

A white long persistence phosphor was synthesized in a single-phase of Mg2SnO4 which was synthesized by a solid-state reaction. This phosphor crystallized in an inverse spinel structure and showed a broad-band emission from 350nm to 700nm. The afterglow was observed upon the excitation by 254nm. A Li-doped Mg2SnO4 sample showed a higher photoluminescence intensity and a longer lifetime than the non-doped one.
Development of New Red Phosphor Na3YSi2O7:Eu3+ for a White LED
Authors: Kousaka Shinichiro , Toda Kenji , Ishigaki Tadashi , Uematsu Kazuyoshi , Sato Mineo
Published: December 2009

New red phosphors Na3YSi2O7:Eu3+ was prepared by a conventional solid-state reaction. This silicate phosphor can be efficiently excited by near UV light, yielding an intense red emission. Under the excitation of near UV light, the emission intensity is higher than that of a commercial red phosphor Y2O2S:Eu3+.
Photochromic Characteristics of Tungsten Trioxide Films Prepared by Electric Current Heating Using Tungsten Wire
Authors: Hagizawa Takumi , Honma Takayuki , Kuroki Yuichiro , Okamoto Tomoichiro , Takata Masasuke
Published: December 2009

Tungsten trioxide films were deposited on the glass substrate by electric current heating method using tungsten wire in air. Applied voltages to the tungsten wire were increased at rates of 0.05, 0.5, 5 and 50 V/min. The resultant films consisted of particles. A particle size of the crystals increased with increasing voltage applying rate. The effects of an ultraviolet (UV) irradiation on the reflectance of the films were investigated. The reflectance in the wavelength range of 500 - 2500 nm decreased by the irradiation. When the films were left in dark after the irradiation, the reflectance returned to the initial. With increasing voltage applying rate, absorption peak shifted toward longer wavelength in the region of 1250 - 1500 nm and the peak intensity decreased.
Pb Displacements in Pb(ZrTi)O3 (PZT)
Authors: Welberry T.R. , Baba-Kishi K.Z. , Withers R.L.
Published: December 2009

Structured diffuse scattering has been observed in selected area electron diffraction patterns of PbZr1-xTixO3 (PZT). This scattering is most evident in the rhombohedral (Zr-rich) phase but has also been observed for a range of compositions including in the important morphotropic phase boundary (MPB) region as well as in the tetragonal (Ti-rich) phase. Monte Carlo computer simulation has been used to show that the scattering originates from the correlation between the displacements of cations in chains running along all four of the cubic <111>c directions. The transverse polarised nature of the scattering means that the ionic shifts are also directed along <111>c. The results are difficult to reconcile with current structural models for the low temperature phases of PZT. It is conjectured that these phases must still contain significant remnants of the disorder present in the high-temperature paraelectric cubic phase.
Textured PbTiO3 Based Ceramics Fabricated by Slip Casting in a High Magnetic Field
Authors: Miwa Yasunari , Kawada Shinichiro , Kimura Masahiko , Higuchi Yukio , Takagi Hiroshi , Suzuki Tohru , Uchikoshi Tetsuo , Sakka Yoshio
Published: December 2009

Textured PbTiO3 (PT) ceramics were fabricated by slip casting in a high magnetic field of 12 T. The sample obtained from the powder calcined at 1100 °C was (100), (010), and (001)-oriented, and the orientation factor was 90 %. On the other hand, the sample obtained from the powder calcined at 900 °C was not oriented. Aggregability and crystallinity of powder are an important factor when textured ceramics are fabricated by slip casting in a high magnetic field.
Electrical Properties of Pb(Mg1/3Nb2/3)-PbTiO3 Ferroelectric Single Crystal
Authors: Shabbir Ghulam , Kojima Seiji
Published: December 2009

The electrical properties of [001]-oriented morphotropic phase boundary (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-33%PT) single crystal have investigated as a function of temperature and frequency. The ac-conductivity exhibited continuous dispersion at all temperatures and frequency range examined and was associated to the thermally activated space charge carriers and local off-centering of Ti4+ and Pb2+ ions. The variations in ferroelectric phase transition temperatures observed in the poled state were associated to the polarization fluctuations and phase co-existence.
Electrical Properties and Phase Transition Behavior of (Li,Na,Ba)(Nb,Ti)O3 Lead-Free Piezoelectric Ceramics
Authors: Aoyagi Rintaro , Rinaldi Rian , Sumiyama Naoki , Iwata Makoto , Maeda Masaki
Published: December 2009

The electrical properties and phase transition behavior of the sodium niobate-based solid solution (1-x)Li0.12Na0.88NbO3-xNa0.91Ba0.09Nb0.91Ti0.09O3 [(1-x)LNN12-xNNBT9] ceramics were investigated. The lattice constant changes became discontinuitous between LNNBT0.5 and LNNBT0.7. Moreover, the peak dielectric constant of LNNBT0.7 is twice that of LNNBT0.5. X-ray diffraction analysis and dielectric study confirmed that the different crystal phases of what are LNN-type rhombohedral (x=0), LNN-type orthorhombic (x=0.1, 0.3 and 0.5), NNBT-type orthorhombic (x= 0.7 and 0.9) and NNBT-type tetragonal (x= 1.0) phases. An electromechanical coupling factor of 0.244 was obtained for LNNBT0.7 whose composition is near the boundary between the LNN-type and NNBT-type orthorhombic phases.
Fabrication and Properties of PZT-Cement-Encapsulated Carbon Composites
Authors: Chaipanich Arnon , Jaitanong Nittaya
Published: December 2009

Lead zirconate titanate, Pb(Zr0.52Ti0.48)O3 (PZT) has excellent piezoelectric properties and has been used in a number of applications such as sensors and actuators. Recently, PZT has been used with a cement based material to produce new types of composite. These new piezoelectric-cement based composites have been developed for sensor applications in civil engineering works where these composites would provide better matching to concrete than the existing normal piezoelectric ceramic or piezoelectric-polymer composites. In this work, encapsulated carbon addition of 2% by volume was added to the PZT-cement composites using pressed-cured method. Dielectric properties of the composites were investigated from 1 to 100 kHz as a preliminary investigation. The results show that the dielectric constant was found to be higher for the composite with the addition of encapsulated carbon. The dielectric loss of the composite with the encapsulated carbon, however, was found to be less when compared to the composite with no encapsulated carbon. Scanning electron micrographs of these composites also revealed that a dense microstructure can be obtained from this method.
Nanocomposite SPEEK/Titania Nanosheets (TNS) Proton Exchange Membranes for Fuel Cell Applications
Authors: Marani Debora , Licoccia S. , Traversa Enrico , Miyayama Masaru
Published: December 2009

SPEEK-based composite membranes containing various amounts of titania nanosheets (TNS) as inorganic fillers were investigated for proton exchange membrane fuel cell applications. The samples were characterized for water uptake, proton conductivity (EIS), and structural features (SEM and XRD). Composites at low inorganic additive contents exhibited improved properties in terms of proton conductivity and water uptake behavior. Best improvements were observed for the composite containing only 0.95 wt% of TNS. This result could be associated to the unique nature of the two dimensional nanostructure of the inorganic additive.
Electrochemical Properties of Porous LiAlXMn2-XO4 Powders Prepared by Immersion of Li and Al Nitrate Solution to Spherical Mn2O3 Powders
Authors: Nishiwaki Kazunori , Ogihara Takashi , Motohira Shigeru , Kodera Takayuki
Published: December 2009

Spherical porous Mn2O3 powders were prepared by spray pyrolysis. Li and Al nitrate solution were immersed to porous Mn2O3 powders to obtain LiAlXMn2-XO4. Homogeneous LiAlXMn2-XO4 powders were formed by the calcination at 800°C. SEM observation showed that they had spherical morphology with particle size of about 1m. XRD revealed that the spinel phase was obtained by heating at 800°C. LiAlXMn2-XO4 cathode obtained by this method exhibited higher rechargeable capacity and cycle stability than that obtained by spray pyrolysis. The doping of Al ion was effective for the cycle stability at elevated temperature.
Proton Conducting Electrolytes Synthesized with Diammonium Hydrogen Phosphate
Authors: Priyanto Dedy Eka , Shiroishi Hidenobu , Tanimoto Satoshi , Hirukawa Shunsuke , Saito Morihiro , Kuwano Jun
Published: December 2009

Proton conducting ZrO2－yP2O5 (y = 1.0, 1.2, 1.4. 1.6, 1.8) electrolytes based on a shell-core structure were synthesized with diammonium hydrogen phosphate by a solid state reaction, and their conductivities were investigated by ac-impedance spectroscopy. Among the ZrO2-yP2O5 compositions, ZrO2－1.6P2O5 showed the highest proton conductivity of 0.13 Scm-1 at 250°C. The conductivity increased with increasing P2O5 molar ratio and were significantly influenced by heat-treatments in the preparation process. Polytetraflouroethylene (PTFE) was also mixed into these electrolytes in order to improve the mechanical strength and long term durability.
Synthesis and Characterization of Samarium Doped Ceria(Ce0.8Sm0.2O1.9) Nano-Particle by Aerosol Plasma Pyrolysis
Authors: Myoujin Kenichi , Ichikawa Yoshiki , Toriyama Araki , Kodera Takayuki , Ogihara Takashi
Published: December 2009

Spherical Ce0.8Sm0.2O1.9 precursor powders were synthesized by Aerosol Plasma pyrolysis using aqueous solution of metal nitrate. As-prepared powders obtained by this method have a spherical morphology with a nano size and submicron size. They had bimodal size distribution. The average size of primary particles was less than 100 nm. The concentrations of starting solution influenced to average particle size. The relative density of SDC pellet was highest when it was sintered at 1623 K. The relative density was 86 %. XRD, SEM, DTA-TG and BET analysis were used for determination of the composition, morphology, particle size and surface area.
Synthesis of Nano-Sized Oxide Phosphor Particles Using an Ion-Exchange Polymer/Water/Oil Emulsion Method
Authors: Sano Hiroyuki , Harada Seiichiro , Shimizu Mikio , Kuwabara Makoto
Published: December 2009

We synthesized nano-sized Eu-doped Y2O3 (Y2O3:Eu) phosphor powder by an ion-exchange po-lymer/water/oil (W/O) emulsion method using carboxymethyl cellulose (CMC) as the ion-exchange polymer, in which the CMC-(Y, Eu) gel formed was calcined at 800°C in air to convert into Y2O3:Eu particles. The obtained phosphor powder consists of unagglomerated particles with sizes in the range of 30-80 nm and exhibits strong red emission at 612 nm. This CMC/W/O method for producing nano-sized oxide powder has significant advantages over conventional solid-phase and chemical solution-based methods because this method can provide unagglomerated nanoparticles of oxide phosphor without employing any mechanical pulverizing process for reducing the particles’ size into the nanometer range; mechanical grinding, such as ball milling, of phosphor powders has been well known to cause a significant degradation of their luminescent properties.
Low Temperature Synthesis of TiO2 from Acid Solution
Authors: Watanabe Soihiro , Nakajima Sae , Uematsu Kazuyoshi , Ishigaki Tadashi , Toda Kenji , Sato Mineo
Published: December 2009

Fine TiO2 particles were synthesized from titanate precursor, Na16Ti10O28, dissolved in aqueous HNO3 solution. Crystalline rutile TiO2 powders were prepared by reflux of dissolved powders in the aqueous HNO3 solution under 100 °C. Prepared TiO2 powders were characterized by X-ray diffraction, thermogravimetry, scanning electron microscopy and BET specific surface area analysis.
Fabrication of PbTiO3 Nanocrystals on Atomically Flat Sapphire Substrates by Sputtering
Authors: Nishida Takashi , Kubo Koichi , Echizen Masahiro , Takeda Hiroaki , Uchiyama Kiyoshi , Shiosaki Tadashi
Published: December 2009

In order to perform the growth position control, PbTiO3 (x=0) (PTO) nanocrystals were deposited on atomically flat and non-atomically flat -Al2O3 substrates by RF magnetron sputtering. The atomically flat substrates with atomic steps and terrace are expected to induce the lateral growth along a terrace between the surface steps. In the case of the atomically flat, the nanocrystals got lined up along the atomic steps, and uniform nanocrystals were obtained on surface in same pitch.
Preparation of Barium Titanate and Strontium Titanate Nanocube Particles and their Accumulation Using Smart Glue
Authors: Nozawa Aki , Kuwabara Tetuo , Uchida Hiroshi , Moriyoshi Chikako , Kuroiwa Yoshihiro , Wada Satoshi
Published: December 2009

Barium titanate (BaTiO3, BT) and strontium titanate (SrTiO3, ST) nanocube particles were successfully prepared by a solvothermal method. The prepared particles were collected by a centrifugal separator. The X-ray diffraction (XRD) measurement confirmed the formation of perovskite BT and ST nanoparticles with sizes of around 17 nm while a transmittance electron microscope (TEM) observation revealed formation of cubic-shaped nanoparticles with sharp edge and corner. These nanocube particles were monodistributed in hexane with tri-n-octylphosphine oxide (TOPO) as dispersant, separately, and then, the 2-dimentional checkerboard-structured accumulations composed of the BT and ST nanocubes were built up using DNA base pair such as adenine and thymine as smart glue. TEM observation confirmed that a part of accumulations had a checkerboard-structure.
The Effect of Reoxidation on Thermal Shock Resistance of SrTiO3-Based Varistors
Authors: Hitomi Atsushi , Chida Naoki , Ogasawara Minoru , Matsuoka Dai
Published: December 2009

The fabrication processes of SrTiO3-based varistors were investigated to obtain highly thermal-shock-resistant devices. It has been found that the reoxidation conditions are strongly related to the thermal cracking ratio (%) of the varistors. A large compressive stress was generated on the varistor surface by reoxidation, consequent upon the lattice parameter difference between its surface portion and its internal portion. This residual stress on the surface is thought to be the key factor of the achieved thermal-shock-resistance.
Millimeter Wave Sintering of AlN Ceramics for Heat Sink Application
Authors: Kishimoto Akira , Morimoto Tetsuya , Hayashi Hidetaka
Published: December 2009

By using 24 GHz millimeter-wave irradiation, full densification of AlN added with Y2O3 was attained at 1700 °C, which is comparable to 28GHz-wave irradiation. Thermal conductivity of a resultant sample exceeded 200 W/mK, which is the highest value in AlN fabricated in non-reducing atmosphere.
New Titanium Oxide Compound for Photocatalytic Water Splitting, Hydrous Na16Ti10O28
Authors: Nakajima Sae , Watanabe Soihiro , Uematsu Kazuyoshi , Ishigaki Tadashi , Toda Kenji , Sato Mineo
Published: December 2009

Photochemical splitting of water into H2 and O2 using solar energy is process of great economic and environmental interest. In this study, we investigated novel photocatalytic compound, Na16Ti10O28, for water splitting. Na16Ti10O28 was prepared by solid-state reaction at 900 oC for 1 h. Prepared sample was characterized using powder X-ray diffraction, diffuse reflectance spectrum, and scanning electron microscopy. As-prepared Na16Ti10O28 sample is easily hydrated in water. Hydrous Na16Ti10O28 showed H2 evolution without co-catalyst.
Dielectric Properties of Low-Temperature Sintered Ba0.6Sr0.4TiO3 Ceramics by Addition of Bi2O3-CuO Mixed Oxides
Authors: Jiang Hai Tao , Zhai Ji Wei , Zhang Jing Ji , Yao Xi
Published: December 2009

The effect of 9Bi2O3-CuO mixed oxides as sintering agent on sintering behaviors and dielectric properties of Ba0.6Sr0.4TiO3 (BST) ceramics were investigated. It was found that 9Bi2O3-CuO mixed oxides lowered the sintering temperature about 300°C and that highly denser BST ceramic pellets were obtained by sintering at 975oC with addition of 5.0-10.0wt% mixed oxides. For BST ceramics with 5.0wt% CB content sintered at 975°C, had a moderate dielectric constant (ε=1315), low dielectric loss (0.0067) and high tunability (36%) at dc electric field of 20kV/cm and at room temperature and at 10kHz.
Investigation on the Effect of Mn on the Dielectric Properties of Ba0.4Sr0.6TiO3/MgAl2O4/MgO Composite Ceramics
Authors: Zhang Jing Ji , Zhai Ji Wei , Zhang Ming Wei , Yao Xi
Published: December 2009

xMnCO3–(1–x)[70wt% (10wt% MgO–90wt% Ba0.4Sr0.6TiO3)–30wt% MgAl2O4] (where x=0.0, 0.5, 1.0, 2.0, 5.0 and 10.0wt%) composite ceramics have been prepared through the solid-state reactions. Three phases, corresponding to the Ba0.4Sr0.6TiO3(BST), MgAl2O4(MA) and MgO phases, are clearly visible in the composite ceramics. The permittivity peak is initially enhanced and shifted toward a higher temperature and then suppressed, shifted toward a lower temperature. Meanwhile, the tunability (calculated by [ε(E0)−ε(E)]/ε(E0)) is also initially improved and then decreased by doping MnCO3.
B-O Bond Character and Microwave Dielectric Properties of (1-x)CaTiO3-xCa(Zn1/3Nb2/3)O3 Perovskite Ceramics
Authors: Shen Jie , Chen Wen , Zhou Jing , Zhu Jie , Lei Qiong
Published: December 2009

The relationship between the character of the B-site cation–oxygen bond and the microwave dielectric properties in perovskites dielectric materials was studied in this paper. The atomic net charge of CaTiO3 (CT) and Ca(Zn1/3Nb2/3)O3 (CZN) was calculated respectively. The calculating result implies that the covalency of B-O bonds in CZN is stronger than that in CT. This predicted that the dielectric constant and loss of the ceramics will decrease after CZN incorporated in CT. To confirme the prediction, (1-x)CT-xCZN microwave dielectric ceramics were prepared by solid state reaction method with ZnNb2O6 as precursor. The structure analysis in terms of tolerance factor gives an identical result as calculation. The microwave dielectric properties, such as dielectric constants, Q×f values and τf were studied as a function of composition. With x increasing from 0.2 to 0.8, the dielectric constant linearly decreases from 109 to 49.37, the Q×f value increases from 8,340 to 13,200 GHz, and τf decreases from 321 to -18 ppm/°C. The properties trends are consistent with the previous calculation results, and confirm the relationship between the character of B-O bond and dielectric properties.
Microwave Characterization Techniques for High K Thin Films
Authors: Sudheendran K. , Raju K.C. James
Published: December 2009

Characterization of the dielectric properties of bulk materials in the microwave frequency range is well developed while that of thin films is a challenge. New microwave characterization techniques are needed for thin films taking in to account the fact that they are always deposited on a dielectric or conducting substrate and the thickness of the film is too small compared to the wavelength involved. In this paper we are demonstrating various techniques that can be used for the microwave characterization of thin films. The microwave dielectric properties of the bismuth zinc niobate (BZN) thin films were characterized at different frequencies using a few techniques by involving coplanar waveguide (CPW) transmission lines circular patch capacitors and split post dielectric resonators. The first two are broadband measurement techniques while the third one is a spot frequency technique.
ZnO Nanoarrays Film Grown by Forced-Hydrolysis-Initiated-Nucleation Technique and its Photo-Induced Electrical Property
Authors: Hu Xiu Lan , Masuda Yoshitake , Ohji Tatsuki , Kato Kazumi
Published: December 2009

Anhydrous zinc acetate pre-coated on the FTO substrate was served as a template layer, and ZnO nanowhisker arrays were simply and successfully fabricated by its forced-hydrolysis-initiated-nucleation of the layer in an aqueous solution at low temperature below 100 °C. The technique doesn’t need any expensive metal catalyst and high-temperature treatment. The density, diameter and length of whiskers were controllable by changing the deposition time. As-grown ZnO nanoarrays showed photo-induced electrical property. Enhanced photo-induced current (2.0~3.0  10-5 A) was detected under laser irradiation after DNA molecules labeled with dye molecules were loaded on the ZnO nanowhisker arrays.
Defect Structure and Electrical Property of Na0.5K0.5NbO3 Lead-Free Piezoceramics
Authors: Matsudo Hitoshi , Kakimoto Kenichi , Kagomiya Isao
Published: December 2009

Na0.5K0.5NbO3 (NKN) lead-free piezoceramics was synthesized by a solid state reaction method. The d.c. conductivitydc and a.c. impedance of the ceramics were measured at the temperature range from 550 oC to room temperature on cooling process. Thedc decreased linearly with decreasing temperature on Arrhenius plot, and the activation energy at the temperature range from 450 to 390 oC and from 390 to 160 oC were 0.65 and 0.90 eV, respectively. The slope change at 390 oC corresponded to Curie temperature of NKN ceramics so that the carriers of these thermally active conductions were alkali metal or oxygen ions in the NKN crystal structure. The impedance of NKN ceramics at high temperature showed two relaxation processes at high and low frequencies, and the leak current was mainly attributed by the conduction through the grain boundary with low impedance value on lower frequency relaxation.
Effects of UV Irradiation on Microstructure and Properties of HfO2 Films Prepared from Alkoxy-Derived Precursor Solution
Authors: Suzuki Kazuyuki , Kato Kazumi
Published: December 2009

The HfO2 films prepared from alkoxy-derived precursor solution chemically modified with diethanolamine. The effects of UV irradiation on the HfO2 films were investigated. The UV irradiation using low pressure mercury lamp (LPML) was effective for the organics decomposition in the film and densification. The uniform and smooth HfO2 films were obtained. The refractive index of HfO2 films was enhanced.
Measurement of d15 Shear-Mode Piezoelectric Response in PZT Thin Film
Authors: Aoki Tsuyoshi , Umemiya Shigeyoshi , Hida Masaharu , Kurihara Kazuaki
Published: December 2009

Piezoelectric films using d15 shear-mode can be applied to many useful MEMS devices. The small displacement derived from the d15 shear-mode was directly observed by a SPM measurement. An isolated PZT(52/48) active part having a pair of driving Cu electrodes was processed in a 5 m-thick sputtering film. The displacement measurement of the active part and its FEM analysis suggested that the estimated d15 piezoelectric constant of the film was 590 pm/V. And, the d31 value of the film was -120 pm/V measured by a conventional cantilever method. The obtained piezoelectric constants of the PZT film are near those of bulk.
Polarized Raman Study for Epitaxial PZT Thick Film with the Mixture Orientation of (100)/(001)
Authors: Nakajima Mitsumasa , Fujisawa Takashi , Nishida Ken , Yamamoto Takashi , Osada Minoru , Naganuma Hiroshi , Okamura Soichiro , Funakubo Hiroshi
Published: December 2009

(100)/(001)-oriented PZT thick films were grown on SrRuO3//(100) SrTiO3 and (100) MgO substrates by matel organic chemical vapor deposition (MOCVD) with different volume fraction of (001) orientation, and were compared with (001) single-oriented epitaxial PZT thick films grown on SrRuO3//LaNiO3//(100) CaF2 by polarized Raman spectroscopy. The spectra from (100)-oriented domain and (001)-oriented domain can be individually observed for the films with the mixture orientation of (100)/(001). Raman analysis revealed the different strain state of (100)-oriented and (001)-oriented domains. Moreover, the rotation dependence of A1(1TO) mode could be explained by the calculation using the volume fraction of (001)-oriented domains obtained from X-ray reciprocal space mapping analysis for the films with the mixture orientation of (100)/(001). These results suggest the local structure characterized by Raman spectroscopy almost agreed with the structure characterized by XRD analysis for the films with the mixture orientation of (100)/(001).
Influence of Cold Work in the Elastic Modulus of the Ti-16.2Hf-24.8Nb-1Zr Alloy Characterized by Instrumented Nanoindentation
Authors: González Marta , Peña J. , Manero Jose Maria , Gil F.J.
Published: December 2009

Nowadays, β type Ti-based alloys have been developed for load transfer clinical applications due to their superelasticity, shape memory effect, low elastic modulus and high damping capacity [1]. These properties promote bone regeneration and make them promising candidates for being used in load transfer implantology. The objective of the present work is to achieve a material with shape memory properties and/or low elastic modulus. The influence of cold work on the thermoelastic martensitic transformation and elastic modulus of the Ti-16.2Hf-24.8Nb-1Zr alloy has been investigated to determine optimal conditions. The homogenized vacuum arc melted button was heat treated at 1100°C during 2 hours and quenched. Samples of each alloy were microstructurally and mechanically characterized after being cold rolled from 5 up to 95%. The elastic response for each condition was evaluated by instrumented nanoindentation by using a Berkovich tip and a spherical tip. A decrease in elastic modulus was observed when increasing the cold work percentage. The lowest value, 44 GPa, similar to that of cortical bone, was found in the 95% cold worked condition.
Influence of the Milling Time on Mechanical and Magnetic Properties of Cu90Co5Ni5 Alloy Obtained by Mechanical Alloying
Authors: López Marta , Gómez M. Elena , Reyes David , Ramam K. , Mangalaraja Ramalinga V. , Prieto Pedro , Jiménez José A.
Published: December 2009

The structure, mechanical and magnetic properties of Cu90Co5Ni5 alloys produced by mechanical alloying and subsequent cold consolidation and sintering behavior, have been investigated. A system of small Co and Ni magnetic particles embedded in the non-magnetic copper matrix were prepared through a mechanical milling process by using a planetary ball mill under argon atmosphere for 20 to 60 h. The morphology and particles size, phase formation and chemical composition of the alloyed powder samples for each milling time were characterized by scanning electron microscope and powder X-ray diffraction techniques, respectively. After milling for 60 h, a supersaturated solid solution with coercive field Hc with maximum value of 235Oe was obtained. The continuous decreasing trend of saturation magnetization (Ms) with increasing of milling time can be explained by the reduction of copper oxide by (CoNi) oxide formation, confirmed by powder XRD patterns. The XRD analyses of the as-milled samples revealed that the Bragg peaks of FCC-Co changed partially to HCP-Co on increasing the milling time. Cu90Co5Ni5 powders cold consolidated and sintered at 650°C for 1h segregated mainly into two-phases of mixed (fcc,hc)-Co and fcc-CuNi. After sintering, the mechanical properties for 60h milling reached its optimum, 26HV in hardness corresponding to 250MPa as compressive strength. TEM microanalysis of sintered alloys revealed Co cluster of 2 to 5 nm in size separated each one by 10 to 20 nm in size. The variation of magnetic properties and its dependence on structural-precipitation change with milling time are discussed.