bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical Characteristics of a Stimulating Microelectrode-Electrolyte Interface
Authors: Sui Xiao Hong , Tan Fei , Ren Qiu Shi
Published: July 2011

The electrochemical stability of the implantable microelectrode array is one of the most important considerations for effective neural stimulation. Electrical characteristics of a polyimide-based platinum microelectrode-electrolyte interface were presented in this paper, which could help determine some stimulus parameters in neural restoration applications. The novel 16-channel Φ-200 μm polyimide-based platinum thin-film flexible microelectrode array was micro-fabricated and an appropriate circuit model of the electrode-electrolyte interface was adopted with three different components of series capacitance Cs, series resistance Rs and Faradic resistance Rf. By using sinusoidal testing signals, the respective changing relationships between the former two components and modulus of impedance Z vs. applied current density were tested in vitro at 37.8°C. The tested results showed that the magnitude of Cs and Rs maintained respective constant values at the low stimulating current density, while with current density gradually increasing, Cs increased and Rs decreased sharply. The tested electrochemical impedance in vitro decreased with the increasing frequency.
Optimization Based on ANSYS Electric Numerical Method for a Novel MEMS ESI-MS Ion Focusing Device
Authors: Yue Cui Hong , Zou He Lin
Published: July 2011

In order to improve the ion transmission efficiency from atmospheric pressure MEMS electrospray (ESI) ion source to mass spectrometry (MS), a novel ion focusing device has been developed and simulated by FEM method (ANSYS). The ion focusing device consists of two electrodes with progressively smaller internal diameters to which electric potential are applied. Taguchi DOE has been used in the optimization process of the structures and critical dimensions for the device. Postprocessing has been implemented by Kriging interpolation method. The shapes of equipotential lines are measured to obtain the response for Taguchi DOE by CAD software. The significance of each factor and optimized structure has been obtained by signal-to-noise (S/N) ratio and means variance analysis. The simulation results will provide good reference for experiments.
Threshold Values Analysis of Substrate Parameters Based on MEMS Microstrip Filter
Authors: Wang Gang , Xu Li Xin , Wang Ting
Published: July 2011

High frequency filters are important components in microwave facilities application. With miniature volume, high performance and integratability, MEMS microstrip filter can significantly improve performance of Radio frequency system. By calculating chebyshev coupled microstrip bandpass filter design scheme, Threshold values of MEMS microstrip substrate parameters are defined to analyze dimensions variation property of MEMS microstrip filter relates with substrate parameters. Selection principle of substrate parameters for MEMS microstrip filter is presented, which indicates thickness and relative dielectric constant of substrate should not exceed the threshold values. The principle of threshold values can be applied as a guide on research and application of MEMS microstrip filter.
Fabrication and Performance Simulation of Microscale Thermoelectric Modules Made with Bi2Te3-Based Alloys
Authors: Liu Da Wei , Li Jing Feng
Published: July 2011

Micro or nano scale thermoelectric (TE) modules have received increasing attention because of their potential applications as energy supplyingand thermal managing components in microelectronic devices and micro-electro-mechanical systems (MEMS). In the present work, microscale thermoelectric modules are fabricated by combining mechanical cutting and photolithograph processes from nano-sized silicon carbide (SiC) particles reinforced Bi2Te3-based materials (Bi2Te3 for n type, and Bi0.5Sb1.5Te3 for p type) prepared by spark plasma sintering (SPS). The fabricated modules have 28 pairs of thermoelectric legs in an area of 3×3 mm2, and each of them is 200×400 µm2 in cross section and 600 µm in length, which is connected in series by Ni-Cu electrodes made with photolithograph patterning and magnetron sputtering. The thermoelectric performances of a p-n couple are simulated with the finite element method (FEM) under a thermal-electrical coupled multi-physics field for both electronic cooling (Peltier effect) and thermoelectric energy generation (Seebeck effect) working mold.
Generation and Application of the Atmospheric Pressure DC Glow Discharge Using Minor Electrodes under N2 Flow
Authors: Liu Kun , Tang Fei , Wang Xiao Hao
Published: July 2011

A new discharge system which can generate stable atmospheric pressure DC glow discharge is reported in this paper. The system is made up of an inner line electrode and an outer cylinder-like electrode. The radii of the inner and outer electrodes are only 0.08 and 2 mm, respectively. The transition from corona discharge to glow discharge is observed. The experiments show that the discharge has typical features of normal glow discharge and can produce nonthermal plasma. It has been used as an ambient ion source, and chemicals such as formic acid, acetic acid, phenol, and benzoic acid can be ionized well.
Patterns of Skylight Polarization at Different Atmospheric Conditions
Authors: Cui Yan , Zou Xiao Chen , Chu Jin Kui , Gao Qi Sheng
Published: July 2011

A skylight polarization measurement system has been designed. With the measurement system, the patterns of skylight polarization measured at four kinds of atmospheric conditions at the spectral range 450~475 nm are presented. It is obvious that qualitatively the patterns of skylight polarization in sunny skies are in agreement with Rayleigh model. The stronger atmospheric turbidity, the greater disturbance to the patterns of skylight polarization appears in the atmosphere. The cloudy sky has terrible patterns of skylight polarization, this is mainly because it is overclouded and the sunlight is occluded completely. The degree of the skylight polarization P and the angle of the skylight polarization χ are the greatest in the clear sky. However, some meteorologic factors can disturb the polarized characteristics of skylight. Cloud layer and dust decrease P of skylight polarization and disturb χ of skylight polarization at different atmospheric conditions.
A Novel Noise Elimination Method for MEMS Sensor
Authors: Lan Jin Hui , Liu Zhi Cheng
Published: July 2011

It is inevitable that measured signals are contaminated with noise when MEMS sensor is used for an outdoor measurement. So the obtained signals need noise elimination, which is one of key technologies for signal conditioning. In this paper, a novel noise elimination method based on algorithm of blind source separation (BSS) for MEMS sensor is proposed to separate the source signals from the mixed signals with noises. The BSS algorithm based on maximum signal noise ratio (SNR) is a method of global optimal property, using the characteristic that SNR is maximal when statistically independent source signals are completely separated.The algorithm has a low computational complexity for instantaneous linear mixture signals. It is effective to acquire the source signals from the mixed signals with noises obtained by MEMS sensor,and is successfully verified by simulation experiment of BSS algorithm.The result of noise elimination experiment has achieved signal conditioning and eliminates ambient noises for MEMS sensor signals.
Nonlinear Ultrasonic Techniques for Testing Micro-Defects in Metal Matrix Composite Structure
Authors: Dun Yi , Wang Shuan Jie , Shi Xiao Hong , Zhou Zhao Ying
Published: July 2011

Micro-defects inside metal matrix composite structure seriously influence the mechanic properties of materials and can undermine machine operations. In order to detect the micro-defects, we can make use of one of the nonlinear acoustic features, i.e., harmonics, which usually appear together with ultrasound when propagating through a damaged material. Based on the relationship between the harmonics, a method of using nonlinear acoustic harmonic amplitude ratio to distinguish micro-defects in metal matrix composite structure is discussed. The test results show that acoustic features, such as second harmonic excitation efficiency were very obvious for the damaged group samples. The method presented is effective in detecting the micro-defects, which means that nonlinear acoustic waves may provide us a good solution for quantitative evaluation of the early damages in metal matrix composite structure.
Microstructure and Properties of Three Phase Carbon and Ceramic Matrix Composites
Authors: Manocha Lalit Mohan , Vyas Milan Mahendrabhai , Manocha Satish , Ralole P.M.
Published: July 2011

Sol-Gel technology was used to develop carbon, silicon and oxygen based ceramics as well as their composites with Carbon fiber and nano siliconcarbide as reinforcements. Gels with different composition were prepared from TEOS, HMDSO and DEDMS. Dried gels were post-cured in air and pyrolyzed at 1000oC in nitrogen atmosphere. Each step of sol-gel process was characterized for density, thermal behaviour and functionality. Composites were prepared using different sols (derived from TEOS, HDMSO and DEDMS) as matrix precursors and carbon fabric as reinforcement. To some composites another phase of solid, micro/nano powder precursor of SiC was added to decrease number of impregnation cycles. Latter composites resulted in higher density. Green composites were post-cured and pyrolyzed. These composites were characterized for density and microstructure. It revealed that the resulting matrix was solid glasses and addition of SiC powder facilitated the rapid densification. Composites prepared with SiC nanparticles as well as Carbon fabric as reinforcement exhibit higher flexural strength than those made without nanoparticles. The fracture behaviour is also seen to be of mixed mode failure type.
Mechanical Properties of Alumina Matrix Composites due to a Combination of Sr- and Ca-Hexaluminates
Authors: Buggakupta Wantanee
Published: July 2011

Alumina matrix composites have been successfully used in a wide range of applications for decades. Even alumina itself provides several desirable properties e.g. strength, chemical and thermal stability together with hardness, its toughness is still to be concerned. An addition of some intermediate phases such as alkali earth hexaluminates can enhance fracture toughness according to their unique morphology. This work investigated a variation in mechanical properties of alumina as a presence of two types of dispersed phases: strontium hexaluminate and calcium hexaluminate. The preformed hexaluminate compounds were prepared from a powder mixture of the alkali earth carbonates and alumina. The preformed hexaluminates were then added into alumina, followed by pressureless sintered at 1600 oC for 2 hours in air. A change in mechanical properties of alumina according to types and amount of additives as well as the ratio of calcium hexaluminate to strontium hexaluminate compounds on was studied. The composites with the relative density of at least 93%TD were achieved. Both hexaluminates resulted in a significant increase in fracture toughness relative to the monolithic alumina while they slightly affected on hardness and strength. When the ratio of calcium hexaluminate to strontium hexaluminate in alumina matrix was considered, a rise in fracture toughness strongly depended on the fraction of calcium hexaluinate. The calcium hexaluminate tended to be more efficient additive in order to strengthen alumina than that of the strontium ones
New Technology with Porous Materials; Progress in the Development of the Diesel Vehicle Business
Authors: Ohno Kazushige
Published: July 2011

The long time of twenty years has passed since Diesel Particulate Filter (DPF) was proposed before the practical use. The main factors that DPF has been put to practical use in this time, are the same time proposal of the evaluation method of SiC porous materials linked to the performance on the vehicle, and that the nature of thermal shock required for the soot regeneration (combustion of soot) in the DPF is different from the conventional requirement for the rather rapid thermal shock. For the requirements, these include demonstrating utmost the characteristic of SiC’s high thermal conductivity, and overcoming the difficulty of thermal expansion of SiC-DPF by dividing the filter into segments binding with the cement of lower Young’s modulus, and the innovation of technology around the diesel exhaust system such as Common-Rail system. As the results of these, the cumulative shipments of SiC-DPF have reached about 13 million, and it goes at no claim in the market.
Optimization of Alumina Slurry Properties and Drying Conditions in the Spray Drying Process and Characterization of Corresponding Coating Fabricated by Atmospheric Plasma Spray
Authors: Bai Yu , Yang Jian Feng , Lee S.W.
Published: July 2011

In this paper, alumina (Al2O3) slurry properties and spraying drying conditions were optimized by orthogonal experiment for preparing the dense and spherical alumina feedstock. The feedstock was carried in a moving gas stream and deposited on the stainless substrate by atmospheric plasma spray (APS).The phase composition and microstructure of feedstock and as-sprayed coatings were studied by XRD, SEM and TEM. In addition, the porosity, surface roughness and micro hardness of as-sprayed coatings were also investigated. The results showed that Al2O3 powder content in slurry was the most influential factor for the particle size and morphology of feedstock and most of α-Al2O3 existing in the starting feedstock transformed into γ-Al2O3 during APS. Moreover, it was found that, using the feedstock prepared by optimized parameters, the as-sprayed coating had an average grain size of about 250 nm, with lower porosity of about 4 %, surface roughness Ra of about 1.94 μm, micro hardness HV0.3 of about 1000 under applied load 300 g.
Effect of NH3 Atmosphere on Preparation of Al2O3-AlN Composite Film by Laser CVD
Authors: You Yu , Ito Akihiko , Tu Rong , Goto Takashi
Published: July 2011

Al2O3-AlN composite film was first prepared by laser chemical vapor deposition (laser CVD) using aluminum acetylacetonate (Al(acac)3) and ammonia (NH3) as source materials. The effects of NH3 on the crystal phase, composition and microstructure were investigated. The crystal phase changed from α-Al2O3 to AlN gradually with increasing the mole ratio of NH3 to Ar. Al2O3-AlN composite film was obtained at NH3/Ar ratio ranged from 0.09 to 0.16 (Tdep = 862–887 K), and AlN granular grains were embedded in between α-Al2O3 polyhedral grains.
Influence of Curing Age on Microstructure in Barium Titanate – Portland Cement Composites
Authors: Rianyoi Rattiyakorn , Potong R. , Jaitanong Nittaya , Chaipanich Arnon
Published: July 2011

The objective of this study was to find out the influence of curing age on microstructure in barium titanate – Portland cement composites. Barium titanate, BaTiO3 (BT) particles was mixed with Portland Cement (PC) and BT content of 50% by volume to produce the composites. All composites were cured in chamber of 60oC and 98% relative humidity for 1, 2, 3, and 7 days. Thereafter, scanning electron microscope (SEM) was used to examine the interfacial zone between cement and BT ceramics. SEM observation indicated that the BT-PC composite cured for 7 days clearly showed calcium silicate hydrate gel (an essential hydration product of Portland cement) surrounding the BT particles and has lower porosity. In BT-PC composite cured for 1 day, the gel can be seen but of less quantity and has higher porosity which clearly affected the interfacial zone.
Comparison of Recession Behavior between Lu2Si2O7 and Lu2SiO5 by High Speed Steam Jet at High Temperatures
Authors: Ueno Shunkichi , Ohji Tatsuki , Lin Hua Tay
Published: July 2011

The recession behavior of Lu2SiO5 and Lu2Si2O7 under high speed steam jet with a velocity of 50 m/s in temperature range between 1300o and 1500oC was compared. Material recession and porous microstructure were observed on the bulk surface for all samples after steam jet tests at the elevated temperatures. The porous structure for Lu2Si2O7 bulk samples become refine with increasing test temperature. On the other hand, the porosity of the porous structure for Lu2SiO5 bulk samples reduced with increasing test temperatures. Phase change was observed for the test of Lu2Si2O7 sample. Lu2SiO5 phase was formed on the Lu2Si2O7 bulk surface in the 1400oC test and Lu2Si2O7 phase was formed again on the surface of the bulk in the test at 1500oC. No phase change was observed in the tests for Lu2SiO5 between 1300o and 1500oC.
The Machinability of 3D-C/SiC Composites
Authors: He Ping , Dong Shao Ming , Zhang X.Y. , Ding Yu Sheng , Gao Lian , Wang Z.
Published: July 2011

Carbon fiber reinforced silicon carbide (C/SiC) composites are considered as one of the most potential thermal structure materials. However, the non-machinability of the three dimension woven fabric restrict the wide application of the c/sic composites. In this paper, we discuss the effect of machinability on the properties of 3D-c/sic composites, such as the modulus, mechanical properties, and so on. The results show that c/sic composites exhibit excellent mechanical properties after machinability, an extensive microstructure study is also carried out to understand the properties of the composites.
Fabrication and Microstructure of Electrically Conductive AlN with High Thermal Conductivity
Authors: Kusunose Takafumi , Sekino Tohru , Niihara Koiichi
Published: July 2011

The electrically conductive AlN with high thermal conductivity were successfully fabricated by sintering AlN with a composite additive of 1wt.% Y2O3 and 4wt.% CeO2 in carbon-reduced atmosphere at over 1600 °C. The sudden increase in electrical conductivity is thought to be caused by transition of grain boundary phase from rare-earth oxide to rare-earth oxycarbide. Their electrical conductivities and thermal conductivities increased with increasing sintering temperature. Additionally, sintering temperature influenced the resultant microstructures.
Analyses of Microstructure and Oxygen Content Effects on Thermal Conductivity of AlN Ceramics by Using Slack’s Plot
Authors: Kobayashi Ryota , Oh-Ishi Katsuyoshi
Published: July 2011

In this study, we analyzed the effect of microstructure and oxygen content on the thermal conductivity of dense AlN ceramics by Slack’s plot, which plots the oxygen content estimated from the lattice parameter c versus the thermal resistivity, which is inverse of the thermal conductivity. The analyses were carried out for the AlN ceramics sintered with oxide additives such as Y2O3, Y2O3-Al2O3, or Y2O3-CaO-B. The data of AlN ceramics sintered with Y2O3 or Y2O3-CaO-B located on the plot of the relation between oxygen content in AlN lattice and thermal resistivity of AlN presented by Slack (Slack’s line) or Harris et al (Harris’s line), respectively. In contrast, the data of the sample sintered with Y2O3-Al2O3, which contains excess grain boundary phases, located above the Harris’s line. These results suggest that the thermal conductivities of AlN ceramics are influenced by not only the oxygen contents in the AlN lattices but also the contents of grain boundary phases.
Impact Fracture Behavior of Ceramics and PE-Fiber-Reinforced Mortars
Authors: Tanabe Yasuhiro , Yamada Masayoshi , Sasoh Akihiro , Kunieda Minoru , Sekine Kiyoto , Kumazawa Takeshi
Published: July 2011

Ceramics will be used for power generating systems in the next generation. When they are used in this system, damage due to foreign object is inevitable. However, few systematic and comprehensive investigations have been reported on this subject. Various ceramics including fiber-reinforced mortars were investigated to understand their behavior when impacted by a spherical projectile. The volume of the cone cracks was large in ceramics which underwent transgranular fracture, while it was small in which underwent an intergranular one. Even though the energy consuming ability by the formation of surfaces was low up to 3.5% of the kinetic energy of a projectile, this ability increased with the ratio of the intergranular fracture to the transgranular one. Boron carbide showed a lower pressure as compared to the other ceramics. Fiber reinforcing increased the ballistic limits, but no clear advantage was suggested when absorbing the kinetic energy of a projectile far over its limits.
Grain-Boundary Segregation and Phase-Separation Mechanism in Yttria-Stabilized Tetragonal Zirconia Polycrystal
Authors: Matsui Koji , Yoshida Hidehiro , Ikuhara Yuichi
Published: July 2011

Microstructure development during sintering in 3 mol% Y2O3-stabilized tetragonal ZrO2 polycrystal (Y-TZP) was systematically investigated in two sintering conditions: (a) 1100-1650°C for 2 h and (b) 1300°C for 0-50 h. In the sintering condition (a), the density and grain size in Y-TZP increased with the increasing sintering temperature. Scanning transmission electron microscopy (STEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, i.e., most of grains were the tetragonal phase, but cubic-phase regions with high Y3+ ion concentration were clearly formed in grain interiors adjacent to the grain boundaries at 1500°C. High-resolution transmission electron microscopy (HRTEM) and nanoprobe EDS measurements revealed that no amorphous or second phase is present along the grain-boundary faces, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries over a width below about 10 nm, respectively. These results indicate that the cubic-phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed this process a “grain boundary segregation-induced phase transformation (GBSIPT)” mechanism. In the sintering condition (b), the density was low and the grain-growth rate was much slow. In the specimen sintered at 1300°C for 50 h, the cubic-phase regions were clearly formed in the grain interiors adjacent to the grain boundaries. This behavior shows that the cubic-phase regions were formed without grain growth, which can be explained by the GBSIPT model.
Synthesis and Electrochemical Properties of Lithium Titanate Anode Materials Powders by Solid State Reaction of Li and Spherical TiO2 Powders
Authors: Yamada Motofumi , Kawaguchi Hiroshi , Kodera Takayuki , Ogihara Takashi
Published: July 2011

Li4Ti5O12 powders were synthesized by solid state reaction of Li2CO3 and spherical composite powders of carbon and TiO2 (denoted as C/TiO2). C/TiO2 powders were synthesized by spray pyrolysis of using lactic acid aqueous solution. The particle characteristics of Li4Ti5O12 powders were determined by SEM, XRD and DTA-TG. DTA-TG showed that the carbon content was around 8 wt% in Li4Ti5O12 powders. XRD revealed that the spinel structure (Fd3m) was obtained by heating at 750 °C under N2 atmosphere. The first rechargeable capacity of Li4Ti5O12 anode was about 160 mAh/g at 1 C. That of Li4Ti5O12 anode decreased to 90 mAh/g at 20 C. The rechargeable capacity of Li4Ti5O12 anode decreased with increasing the rechargeable rate, but 81% of initial discharge capacity of Li4Ti5O12 anode was retained after 200 cycles at 1C
Characterization of Low Temperature Chemical Vapor Deposited Gd2O3 Doped CeO2 Films
Authors: Saotome Ryoichi , Wakiya Naoki , Kiguchi Takanori , Cross Jeffrey S. , Sakurai Osamu , Shinozaki Kazuo
Published: July 2011

Highly oriented and polycrystalline Gd2O3 doped CeO2 thin films were prepared on α-Al2O3(0001) substrates by chemical vapor deposition, using Ce(C5H4C2H5)3 and Gd(C5H4C2H5)3 as precursors. The compositions of the films were controlled by optimizing the vaporization pressure of Gd precursor under the constant vaporization condition of Ce precursor. In-plane electrical conductivities of the films at various temperatures and oxygen partial pressures were evaluated by electrochemical impedance spectroscopy measurements. The activation energy of the film was determined as 0.94 eV, which is comparable with that of pulsed laser deposited films.
Performance of Intermediate Temperature Fuel Cells with Proton Conducting Electrolytes Synthesized with Diammonium Hydrogen Phosphate (1)
Authors: Yonekawa Minoru , Kano Shigeki , Shiroishi Hidenobu , Tateishi Hikaru , Ayato Yusuke , Saito Morihiro , Kuwano Jun
Published: July 2011

The (ZrO2-1.6P2O5)-PTFE composite electrolytes have been prepared by mixing PTFE powders with different particle sizes and the shell-core-type ZrO2-1.6P2O5electrolyte, synthesized by solid state reaction with diammonium hydrogen phosphate, to improve the mechanical strength of the electrolyte. The H2gas permeability decreased and the cell performances improved with decreasing PTFE-particle size. The aging at 0.4 V above 443 K enhanced the ITFC performance owing to the penetration of the electrolyte to the carbon paper. The maximum output power enhanced by 63% after 15 h of aging at 573 K.
Preparation and Characterization of Dye-Sensitized Solar Cells Containing TiO2 Nanotube Clusters/Nanoparticle Hybrid Films
Authors: Hayashi Kazuho , Nakamura Takahiro , Ogihara Takashi
Published: July 2011

TiO2 nanotube array films were synthesized by the anodic oxidation of a Ti plate in an NH4F electrolyte. The thickness of the films was dependent upon the oxidation time. Nanotube clusters were produced when the films were subjected to sonication. Pastes were subsequently prepared by mixing the nanotube clusters with TiO2 nanoparticles. The pastes were used to fabricate photoelectrodes of dye-sensitized solar cells. The generation efficiencies of cells with TiO2 nanotube clusters were lower than those of cells without these clusters. TiO2 nanotube clusters were very large, and therefore, they might have intercepted the ionic transport.
TEM Observation on Ferroelectric Domain Structures of PbTiO3 Epitaxial Films
Authors: Aoyagi Kenta , Kiguchi Takanori , Ehara Yoshitaka , Funakubo Hiroshi , Konno Toyohiko J.
Published: July 2011

The ferroelectric domain structure of PbTiO3(PTO) films was investigated by using transmission electron microscopy (TEM). In the film with PTO/SrTiO3(STO) structure, 180º domains are formed near the SrTiO3(STO) substrate and the domain length of 180º domains is 100 nm. However, 180º domains are not formed in the film with Pt/PTO/SrRuO3(SRO)/STO structure. These results show that 180º domains are formed in order to minimize depolarizing field energy, and that the domain length of 180º domains is determined by the competition among the depolarizing field energy, domain wall energy, Coulomb interaction and elastic interaction.
Fabrication of BaTiO3 Films on Si Substrate by Inkjet Printing
Authors: Komatsu Ai , Hoshina Takuya , Kunej Spela , Takeda Hiroaki , Tsurumi Takaaki
Published: July 2011

BaTiO3 films were fabricated on Si substrate using inkjet printing technique. To achieve low-temperature fabrication of BaTiO3 films, Ba-Ti-alkoxide ink was prepared. The mixing ratio and sequence of raw materials were optimized for controlling the chemical stability and viscosity of alkoxide ink. The inkjet printing films on Si substrate were annealed at 700 °C, and it resulted in the formation of BaTiO3. It was found that the film quality was improved by adding BaTiO3 nanoparticles into the Ba-Ti-alkoxide ink.
Dielectric Properties of Bismuth Layer-Structured Oxide Thin Films with Preferential Crystal Orientation at High-Temperature
Authors: Mizutani Yuki , Kimura Junichi , Takuwa Itaru , Yamada Tomoaki , Funakubo Hiroshi , Uchida Hiroshi
Published: July 2011

Thin films of MBi4Ti4O15 (M = Ca and Sr) with preferential crystal orientation were fabricated using underneath perovskite layers on various substrates. One-axis BLSD films on (100)LaNiO3/(111)Pt/Ti/(100)Si and epitaxial BLSD films on (100)SrRuO3//(100)SrTiO3 were fabricated by chemical solution deposition (CSD). Dielectric constants of the CaBi4Ti4O15 and SrBi4Ti4O15 films on (100)LaNiO3/(111)Pt/Ti/(100)Si were approximately 250, while those on (100)SrRuO3//(100)SrTiO3 were 220, respectively. The temperature coefficients of capacitance (TCCs) of these films were below 10% in atmospheric temperature range between R.T. and 300°C, which is significantly smaller than those of conventional (Ba,Sr)TiO3-based capacitors.
Low-Loss Transmission Characteristics of Transparent Conductive Thin Films in GHz Range
Authors: Ogino Tsuyoshi , Ohashi Naoki , Hishita Shunichi , Sakaguchi Isao , Adachi Yutaka , Nakajima Kunihiko , Haneda Hajime
Published: July 2011

The resistivity of transparent conductive thin film formed by sputtering exhibits a dependence on film thickness. In this study, an analysis by electromagnetic field simulation of resistance effect on the transmission characteristics was carried out. The overall resistance of the signal waveguide governs the transmission characteristics, and variation of the resistance at the interface between the substrate and the thin film has no significant effect. We evaluated a structure in which fine metal wiring that is not visible to the eye is placed on transparent conductors to reduce the resistance of the transmitting waveguide. Electromagnetic field simulations suggest that this structure improves the transmission characteristics while keeping high transparency.
Fabrication and Evaluation of Al2O3 Films Using the Aerosol Deposition Method
Authors: Uemichi Yuta , Nishikawa Koji , Sato Yuuki , Yoshikado Shinzo
Published: July 2011

Equipment was designed for the application of Al2O3 thin films by the aerosol deposition method (ADM) at room temperature. Al2O3 film could be deposited on Pyrex-glass, indium tin oxide (ITO), polyvinyl chloride (PVC) plastic, single crystal silicon, and sapphire substrates. The films had the same crystal structure as the raw material particles and were highly transparent. The breakdown electric field of the Al2O3 film for the ADM was more than 35 kV/mm.
Low Temperature Preparation and Optical Hydrogen Response of Pd/Titania Composite Film
Authors: Hamagami Junichi , Araki Ryo , Onimaru Shohei , Oda Hiroyuki , Kawamura G. , Matsuda Atsunori
Published: July 2011

Photocatalytic titania coatings loaded with palladium catalyst were prepared onto soda-lime glass substrates by using a low temperature synthesis for application of optical hydrogen gas sensor. Titania coatings were formed on the glass substrate by a sol-gel spin-coating process followed by a hot water treatment at 55°C. Metallic palladium nanoparticles were deposited onto the titania coatings, which obtained with addition of poly(ethylene glycol) (PEG) and without PEG after the hot water treatment, by means of a photodeposition technique at room temperature using UV-light irradiation. The whole fabrication process was carried out under atmospheric pressure. The Pd-photodeposited titania coating obtained with addition of PEG after hot water treatment showed higher hydrogen sensing properties than that obtained without PEG.
The Effect of Citric Ion on the Spin-Sprayed ZnO Films: IR and XPS Study for the Organic Impurities
Authors: Wagata Hajime , Ohashi Naoki , Katsumata Ken Ichi , Okada Kiyoshi , Matsushita Nobuhiro
Published: July 2011

ZnO films with controlled microstructures and crystal orientations were fabricated on nonseeded substrates by a spin-spray method employing tri-sodium citrate as a structure-directing agent at 90°C. The microstructure of the films changed from a rod array to a dense film by addition of the tri-sodium citrate in the solution. The FT-IR spectra of the films prepared with citrate contained organic molecules including carboxyl groups, being attributed to citric ion. Surface analysis by XPS indicated that the adsorbed citric ions were estimated to form zinc-citrate complex including ammonium ion or ammonium citrate.
Evaluation of Compact X-Ray Source Using Multiple LiTaO3 Single Crystals
Authors: Honda Hiroyuki , Fukao Shinji , Ito Kazuyuki , Guan Yang , Nakanishi Yoshikazu , Sato Yuuki , Ito Yoshiaki , Yoshikado Shinzo
Published: July 2011

Three and six LiTaO3 single crystals are used to achieve continuous emission of high-intensity X-rays. Furthermore, the interaction between X-rays and the case of the X-ray source is used to generate electrons. X-rays were emitted continuously and fluctuations in the count rate were reduced when three or six crystals were used. Moreover, the X-ray intensity increased and the number of electrons generated by the above-mentioned interaction increased with increasing number of crystals.
Kinetics of Oxygen Diffusion into Multilayer Ceramic Capacitors during the Re-Oxidation Process and its Implications on Dielectric Properties
Authors: Kaneda Kazumi , Mizuno Youichi , Donnelly Niall J. , Lee Soonil , Qu Wei Guo , Randall Clive A.
Published: July 2011

Re-oxidation is an important thermal process to minimize oxygen vacancies and produce high reliable Ni-MLCCs. The re-oxidation of these devices is then investigated with a series of “in-situ” impedance measurements between 400 and 500 °C in air. From the relative impedance change, chemical diffusion coefficients, associated activation energy and effective equivalent circuit model are determined. Those values were found to be reasonable compared with previous researchers’ data. Moreover, the proposed effective equivalent circuit model successfully represents the real Ni-MLCC morphology. From transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS), it is found that the electrical properties and reliabilities of the Ni-MLCCs re-oxidized under different conditions are identical.
Piezoelectric Properties of (Li, Na, K)NbO3 Ceramics with Monoclinic System
Authors: Hatano Keiichi , Kobayashi Keisuke , Hagiwara Tomoya , Shimizu Hiroyuki , Doshida Yutaka , Mizuno Youichi
Published: July 2011

The Relationship between the Piezoelectric Properties and Crystal Lattice Deformation and Distortion Resulting from the Li Substitution in LiXNa0.52K0.48-XNbO3, Alkaline Niobate-Based Perovskite Ceramics of (Li, Na, K)NbO3, Was Investigated. the Lattice Parameters of the Sample with a Li Content X = 0.05 and Having a Monoclinic System with Space Group PM Were a = 3.9789(6) Å, B = 3.9385(5) Å, C = 4.0134(6) Å, and B = 90.305(4)º. the ET33/e0, Kr, and -D31 Values of the Sample by Poling in the Monoclinic System Were 450, 44.6%, and 57 PC/N, Respectively. on the other Hand, the ET33/e0, Kr, and -D31 Values of the Sample by Poling in the Tetragonal System Were 600, 38.7%, and 56 PC/N, Respectively. the Remarkable Piezoelectric Properties of these Ceramics Can Be Attributed only to the Low Symmetry of their Monoclinic System, which Is a Subgroup of aMm2 and P4mm. Li0.05Na0.52K0.43NbO3 Ceramics with a Monoclinic System Were Observed to Have the Unique Piezoelectric Characteristics.
Ferroelectric and Piezoelectric Properties of Bi4Ti3O12 Single Crystals Grown by Top-Seeded Solution Growth Method at High Oxygen Pressure
Authors: Kitanaka Yuuki , Noguchi Yuji , Miyayama Masaru
Published: July 2011

High-performance single crystals of ferroelectric Bi4Ti3O12 (BiT) have been successfully obtained via the top-seeded solution growth under high oxygen pressure (Po2) atmosphere. Crystals grown at 960°C at a Po2 of 0.9 MPa exhibited a well-saturated hysteresis loop with a remanent polarization of 48 mC/cm2 and a coercive field of 29 kV/cm. The results of piezoresponse force microscopy indicate that polarization switching is accomplished throughout the BiT crystals obtained. Electric-field-induced strain measurements along the a axis yield a piezoelectric constant d11* of 37 pm/V for BiT.
Modeling of β→α Transformation in Complex Titanium Alloys
Authors: Di Napoli Paolo , Appolaire Benoît , Aeby Gautier Elisabeth , Bénéteau Adeline
Published: July 2011

A model has been developed which is able to predict the kinetics of β → α transformation in industrial multicomponent titanium alloys during complex heat treatments. It isbased on (i) analytical nucleation and growth laws based on simple geometric representationsof the di erent morphologies commonly observed in these alloys; (ii) the assumption of localequilibrium at interfaces, handled within the CalPhaD framework; (iii) averaged solute balancesin each morphology. The potentialities of the model will be demonstrated on the Ti17 industrialalloy upon isothermal holdings and cooling from the β phase field.
Precipitation Sequences in Two Al-Li-Cu Alloys
Authors: Decreus Benjamin , de Geuser Frédéric , Deschamps Alexis , Donnadieu Patricia , Sigli Christophe
Published: July 2011

The precipitation sequences in two Al-Li-Cu alloys with similar Cu concentration and different Li concentration have been studied by small-angle X-ray scattering using synchrotron light, in combination with transmission electron microscopy. The sequence ranges from phases formed during natural ageing to the hardening ones obtained by artificial ageing at 155°C. It is found that the low Li-containing alloy shows first Cu-rich clusters at room temperature followed by T1 precipitates, while the high Li-containing alloy shows first δ’-Al3Li precipitates and then formation of T1 phase in coexistence with the δ’. The influence of alloy composition on T1 nucleation and growth kinetics is discussed in light of the experimental results.
Phase Transformations in the NiS Nickel Sulphide: Microstructure, Mechanisms and Modelling through In Situ Microscopy.
Authors: Yousfi Oussama , Bréchet Yves J.M. , Donnadieu Patricia , Robaut Florence , Charlot Federic , Kasper Andreas , Serruys Francis
Published: July 2011

Nickel sulphide (NiS) can form inclusions in tempered glass which lead to fracture due to a phase transformation with a volume change of about 4%. A heat treatment, aiming to provoke this phase transformation, is currently used in industry to reduce this effect. In order to propose more efficient treatments, a complete study going from identification of the transformation mechanisms to the modelling of the transformation was carried out. Depending on stoichiometry and temperature, two mechanisms for the transformation (partitioned or partitionless) have been evidenced by detailed microstructural and calorimetric studies leading to a fruitful parallel with the Fe-C phase transformations which provides the basis for further modelling of the kinetics. An in situ follow up of the transformation by optical microscopy has given information (like nucleation rate and interface migration velocity) necessary to build the kinetic models. This modelling is based on Zener and Zener-Hillert kinetics models for interface velocity and described the transformation under isothermal treatment and anisothermal conditions.
Research on CBN Grinding Wheel Dressing with Ultrasonic Vibration Assistance and its Grinding Performance
Authors: Gao Guo Fu , Zhao Bo , Li Yu , Tong Jing Lin
Published: July 2011

The experiment of resin-bonded CBN wheel dressing using a diamond dresser assisted with longitudinal ultrasonic vibration along the direction of depth of cut was carried out and the dressing characteristics and grinding performance were discussed in the present paper. The influence of acoustic parameters on the topography of CBN wheel was studied to check the effectiveness of dressing for this method. The experimental results showed that the higher the ultrasonic frequency is, the better the wheel topography. The grinding on K9 optical glass and high speed steel has achieved higher G-ratio than that of traditionally mechanical dressed CBN grinding wheel. The ground surface of high speed steel is better than that of K9 optical glass. According to the interferometer images, it was concluded that the grinding of high speed steel was in ductile cutting regime, while removal of K9 optical glass was in brittle fracture regime.
A Method to Investigate Stability of Silicon Coating on Diamond Substrate by First Principle Calculation
Authors: Li Dong Xu , Lu Jing , Yu Dong Li
Published: July 2011

Diamond with inorganic coating such as silicon coatings was used to promote applications. Different kinds of silicon structures were found in the coatings. In this paper, first principle calculation was used to study the stability of cubic silicon and hexagonal silicon coatings deposited on diamond substrate. The simulation data suggest that the single layer hexagonal silicon coating form easily under low temperature due to the low lattice mismatching and thermodynamic temperature. However, the stronger bonding of Si-C bonds between substrate and coating direct the formation of cubic silicon coatings, as well as Si-Si bonds inner coatings, in agreement with experiments.
A Polishing Method of Single-Incentive Ultrasonic Elliptical Vibration for Tungsten Carbide Mould
Authors: Yin Shao Hui , Xu Zhi Qiang , Yu Jian Wu , Wang Ze Biao
Published: July 2011

The basic principles of ultrasonic transducer and ultrasonic elliptical vibration polishing are investigated. A new kind of single-incentive ultrasonic transducer is designed, and the finite element simulation is conducted, a polishing device is developed based on the ultrasonic elliptical vibration. The polishing experiment is adopted to polish a tungsten carbide mold with the diameter 5cm. The experimental result shows that the tungsten carbide mould surface roughness changes from the original 0.026μm to 0.017μm.
A Comparative Study on Ultrasonic Machining of Red Granite
Authors: Zheng Shu You , Xu Xi Peng
Published: July 2011

Ultrasonic machining has been proven to be a promising machining method on hard and brittle materials. However, due to the absence of high power ultrasonic machine tools, reported studies on ultrasonic machining were mainly concerned of relatively small hole drilling of the given materials. In the present work, with the development of the higher power Rotary Ultrasonic Machine Tool, two kinds of ultrasonic face machining with free abrasives, namely, Non-rotating Ultrasonic Machining with Free Abrasives (NRUSM) and Rotary Ultrasonic Machining with Free Abrasives (RUSM) are designed and comparatively conducted for the red granite, which is a typical hard-to-machine natural material. The effects of static force, spindle speed and amplitude of ultrasonic vibration on the performance of the machining are evaluated in terms of the material removal rate and surface quality. Experimental results indicate that ultrasonic machining is effective for face milling of the stone material with the designed machine tool. Furthermore, machining performances in RUSM are superior to those in NRUSM.
Coating SiC Whiskers with Protective Si Films for Al Matrix Composite
Authors: Lu Jing , Wang Yan Hui , Xu Xi Peng
Published: July 2011

In SiC whisker reinforced Al matrix composite, the interface reaction significantly influences the property of the composite. Si films have been deposited on SiC whiskers by quasi atomic layer deposition from gaseous SiH4 to protect the whiskers from being eroded by Al matrix. The structure and morphology of the coating were characterized by X-ray diffraction and transmission electron microscope. The coating deposited on SiC whiskers is cubic phase polycrystalline silicon and this ultrathin Si film is even and continuous, completely covering every individual SiC whisker. The effect of the Si coating on improving the whisker/matrix interaction was also studied in this work. The interface layer, Si coating, could effectively protect the SiC whisker from erosion caused by Al matrix during the high temperature manufacturing process and improve the adhesion between the SiC whisker and the Al matrix.
Flow Dynamic Simulation of Micro Abrasive Water Jet
Authors: Fan Jing Ming , Fan Chang Ming , Wang Jun
Published: July 2011

Simulation of the dynamic characteristics of micro abrasive water jet (MAWJ) is conducted using computation fluid dynamics (CFD) software Fluent 6.3 flow solver. The velocity distributions and particle behaviors of the free jet and impinging jet in and out of the nozzle are investigated under different input and boundary conditions. In the free jet simulation, a reduction in water pressure corresponds to more rapid decay of the jet velocity along the jet axis, whereas particle mass concentration has no influence on the jet velocity. In the impinging jet simulation, the effect of the impingement surface on the flow field increases with a decrease of the stand-off distance. The simulation results in this study provide the foundation for optimizing the nozzle structure and improving cutting efficiency and cutting performance of MAWJ.
Experiment Study on Impact Disrepair of Different Groove Milling Inserts for Machining High-Strength Steel
Authors: Cheng Yao Nan , Liu Xian Li , Yan Fu Gang , Li Yu Fu , Li Zhen Jia
Published: July 2011

Based on the experiments on milling the 3Cr-1Mo-1/4Vsteel which is the main part of the large chemical equipment hydrogenation reactor with several types of different grooves milling inserts, we have experiment study on the impact disrepair. Using the Orthogonal experimental design method, we have cutting experiments on machining the high-strength steel with several types of different grooves milling inserts, and find out the difference of the impact disrepair invalidation types among them. Based on the plentiful and systemic impact disrepair experiments, we build the impact disrepair life cumulating distribution function mathematic model by the mathematics statistic method. We have contrast analysis of the impact disrepair average lives among these types of milling inserts, and the different grooves milling inserts are optimized. All these studies provide the theoretic and experimental bases for solving the cutter disrepair which is the key problem in the actual production and groove optimization.
Fracture Morphology of Composite CBN Wheel Segments Based on Graphite Self-Lubricating Effects
Authors: Chen Zhen Zhen , Xu Jiu Hua , Ding Wen Feng , Huang Jia Lin
Published: July 2011

Multilayer brazed CBN wheel segments based on graphite self-lubricating has been fabricated. The bending strength of wheel segments was measured and the fracture morphology of tested segments was detected. The results show that the bending strength of segments with CBN grains decrease to a small extent from 116MPa to 97MPa with the linear increase of graphite content from 5 wt.% to 15 wt.%. Due to the poor strength and certain stress concentration by the added graphite, the fracture interface transfers from the whole CBN grains to the bonding matrix with the increasing of the graphite. In addition, the pore sizes are decreased obviously.
Genetic Algorithm-Based Optimization of the Thin-Walled Tube of High Strength Aluminum Alloy in Diamond Turning Process
Authors: Zhang Bao Xing , Lin Bin , Han Zhi Lin , Zhang Lei
Published: July 2011

Optimization of the cutting parameters is one of the most important contents in diamond turning process of the thin-walled tube of high strength aluminum alloy. Cutting conditions have an influence on reducing the production time and deciding the quality of the final workpiece. This paper proposes an optimization technique based on genetic algorithms (GA) for the determination of the cutting parameters. As the experimental results show, it is very efficient that the proposed genetic algorithm-based procedure for solving this problem.
Finite Element Simulation of Nickel-Based Alloy Cutting Process Based on DEFORM- 3D
Authors: Ren Jia Long , Zhang Chun Yan , Yuan De Peng
Published: July 2011

To analysis cutting mechanism and heat transfer coefficient of Ni-based superalloy IN718, this paper introduced a three-dimensional finite element model for cutting process based on DEFORM-3D V6.1, and cutting force Fy and cutting temperature T under different feed rate f , cutting speed v and back engagement ap were obtained. The temperature variation during cutting process under different cooling method was analyzed. The simulation results indicate that the influence of back engagement ap on the cutting force Fy is the greatest, while that of cutting speed v is minor; and for cutting temperature T, influence of cutting speed v is the greatest, while that of back engagement ap is minor. Influence of heat transfer coefficient on highest temperature and average cutting force Fy is minor, but its influence on average temperature is quite obvious. Greater heat transfer coefficient is less average temperature.