bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement in the Sensitivity of the Response of Diamond Thin Films to X-Ray
Authors: Liao Xiao Ming , Ran Jun Guo , Gou Li , Zhang Jin , Su Bao Hui , Lin Jiang Li
Published: March 2009

Due to some inferior performance of Chemical Vapor Deposition (CVD) diamond dosimeters, their applications are somewhat limited. The quality of diamond films was improved using Microwave Plasma CVD (MWPCVD) by the modified processes such as cyclic deposition and in-situ plasma post-treatment. The simple radiation dosimeters were fabricated in a sandwich configuration. Influence of purity and orientation of the diamond films on the sensitivity of the dosimeters was studied. The results indicate that the radiation dosimeters have high sensitivity to X-ray and the response of the devices is linear with the X-ray flux. The higher the purity of films is, the higher the resistivity and sensitivity are. The dosimeter based on [100] film has higher sensitivity than that based on [111] film. The dosimeter based on films prepared by cyclic deposition has higher sensitivity than that based on films prepared by the conventional deposition. The characterization of the response to X-ray also shows that in-situ oxygen plasma post-treatment leads to the higher sensitivity of dosimeters compared with in-situ nitrogen, hydrogen plasma post-treatments.
Low Thermal Conductivity Ceramics for Thermal Barrier Coatings
Authors: Qin Ye Xia , Wang Jing Dong , Pan Wei , Wan Chun Lei , Qu Zhi Xue
Published: March 2009

This paper summarizes the basic properties of a series of rare-earth zirconate ceramics
(Gd2Zr2O7, Sm2Zr2O7, Dy2Zr2O7, Er2Zr2O7 and Yb2Zr2O7). The phases and microstructures were
characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal properties
of these materials were determined. The results indicated that Sm2Zr2O7 rare-earth zirconate ceramics
have the lower thermal conductivity and the highest thermal expansion coefficient than other rare-earth
zirconate ceramics. The dielectric constant decreases with the increase of atomic number.
Thermophysical Properties of Samarium-Cerium Oxide for Thermal Barrier Coatings Application
Authors: Wan Chun Lei , Pan Wei , Qu Zhi Xue , Qin Ye Xia
Published: March 2009

Sm0.4Ce0.6O1.8 specimen with a defective fluorite structure was synthesized and its thermophysical properties were characterized for thermal barrier coatings (TBCs) application. At high temperature, Sm0.4Ce0.6O1.8 exhibited much lower thermal conductivity than 7wt% yttria-stabilized zirconia (7YSZ)-the commonly used composition in current TBCs. Sm0.4Ce0.6O1.8 also possessed large thermal expansion coefficient, which could help reduce the thermal mismatch between the ceramic coating and bond coat.
Practice of Simulation to Formation of Rock Theory
Authors: Feng Xiang Peng , Sun Heng Hu , Liu Xiao Ming
Published: March 2009

The utilization of industrial solid wastes as building materials has been thought of as the best
way to solve the problems caused by high waste production, high resource consumption and high
pollution that is inherent with the primary industries of China. However, due to the low level of usage by
previous technologies, these serious problems of the primary industries still persist. Hence, it is urgent to
seek an effective way to solve these problems. In this paper, based on the understanding of the theory of
simulation to formation of rock and the research advances of sialite technology, it is concluded that sialite
technology can achieve the effective usage of industrial solid wastes.
Effects of Boron-Doped on Photocatalysis and Hydrophilicity of TiO2 Film
Authors: Li Hong , Zhao Gao Ling , Xu Gang , Han Gao Rong
Published: March 2009

In order to investigate the effects of doping boron on the self-cleaning properties of TiO2 thin
films, sol-gel method was employed to prepare TiO2 films with various amount of boron on the glass
substrates. Atomic Force Microscope (AFM) and X-ray diffraction (XRD) were carried out to investigate
the effects of boron on the microstructure and crystallization behavior of the thin films. The
photocatalytic activity and the hydrophilicity of the films were also measured. The results showed that the
photocatalytic activity of TiO2 films was improved by doping boron, and its hydrophilicity wasn’t
destroyed. This can be ascribed to the enhancement of the surface energy, which was caused by the
reduction of the crystal grain size of TiO2.
Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.15]O3+δ Ceramics with Ba2+ Substitution at A-Site
Authors: Zhou Dong Xiang , Xiong G. , Gong Shu Ping , Zhao Jun , Hu M.Z. , Li H.
Published: March 2009

The microwave properties of (Ca1-xBax)[(Li1/3Nb2/3)0.95Zr0.15]O3+δ(0.0≤x≤0.2, CBLNZ)
ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x =
0.0 − 0.025. Both the εr and Qf value firstly increased with increasing Ba2+ content, and then began to
decrease at x = 0.025. The τf value increased from −9.4 ppm/°C at x=0.0 to 18ppm/°C at x=0.2, which
could be explained by the decrease of B-site bond valence in perovskite structure.
Factors Influencing the Photocatalytic Efficiency in the Experimental for the TiO2 Powder Slurry Systems
Authors: Kim Kwang Wook , Lee Mi Hye , Yoon Dae Hyun , Shin Dong Woo
Published: March 2009

The photocatalytic efficiencies of three commercially available TiO2 samples were
evaluated and compared for TiO2 powder dispersed system with respect to pH and the water to be
used for the perpetration of TiO2 slurry. All the TiO2 samples of P-25, NT-C, NT-20 showed a
significant dependence of the photocatalytic efficiency on pH and exhibited higher photocatalytic
efficiency in the pH between 5 and 7. The water used for the preparation of the TiO2 slurry also
affected the photocatalytic efficiency of the TiO2 samples presumably due to a few cation ions
existing in the water. The photocatalytic properties of TiO2 samples varied significantly depending on
the key experimental conditions applied to the TiO2 slurry.
Preparation of Ferroelectric K0.5Na0.5NbO3 Films by Sol-Gel Processing
Authors: Lai Feng Ping , Li Jing Feng , Gong Wen
Published: March 2009

Orthorhombic perovskite-type K0.5Na0.5NbO3 (KNN) films on Pt/Ti/SiO2/Si substrates were
prepared by sol-gel processing. The morphology of the films was characterized using SEM and AFM. The
KNN films with a total thickness of about 0.5 micron had relatively dense and uniform microstructure.
The ferroelectricity of the KNN films was confirmed by polarization-electric field (P-E) hysteresis loop.
Preparation of Pottery from Shale
Authors: Tang Xiu Ling , Han Min Fang , Wang Qi
Published: March 2009

The main chemistry ingredients of the shale in Baoding, China, are SiO2 and Al2O3, and the
mineral components are quartz, feldspar and mica. The shale was sintered to produce pottery at 1000 ~
1300°C and its deposit density and expansion ratio were measured. The compressive strength, apparent
density, water absorption, etc, of some sintered samples with expansion ratio more than 1.5 were
measured according to GB/T17431.2-1998. When sintered at 1150°C for 15 min, the expansion ratio of
the shale is 1.96. When sintered at 1200°C for 10 min, the expansion ratio is 2.00. The performances of
the prepared pottery accord with GB/T17431.2-1998: the compressive strength is 3.8MPa with the
expansion ratio 1.96, the compressive strength is 4.2MPa with the expansion ratio 2.00. The water
absorption is 4.9~5.8%, according with GB/T17431.2-1998.
Corrosion Resistance Properties of Carbon Nanotube Reinforced Electroless Composite Coating
Authors: Zhao Guo Gang , Zhang Hai Jun , Wang Zhen Ting , Zhang Ying Chun
Published: March 2009

The carbon nanotube reinforced Ni-P matrix composite coating on 45# steel has been prepared by electroless plating method in this study. The microstructure and the corrosion properties of the composite coating were investigated systematically using SEM and a potentiostat. SEM results show that the carbon nanotube was uniform embedded in the crystal grains of Ni-P. The polarization curves indicate that the composite coating exhibit excellent corrosion resistance properties which is superior to that of the conventional Ni-P coating.
Fabrication of LaNiO3 Chain-Like Ceramics from Nanocable Precursors
Authors: Deng Yuan , Li Jian , Guo Lin , Yang Qin Lin
Published: March 2009

One-dimensional LaNiO3 nanochains can be generated with high yield by a simple calcination
process using La(OH)3/Ni(OH)2 coaxial nanocables as parent template. Those coaxial nanocables can be
synthesized by a simple hydrothermal method. The final LaNiO3 ceramics keep the morphology of parent
precursor.
Sintering Behavior of Pure and Nb-Doped BaTiO3 Powder Prepared by High-Gravity Reactive Precipitation
Authors: Wang Xiao Hui , Liu Xiao Lin , Yan Tao , Chen Jian Feng
Published: March 2009

Sintering behavior of pure and Nb-doped barium titanate powders prepared by high-gravity
reactive precipitation (HGRP) process was investigated. A thermal dilatometer was employed to monitor
the sintering shrinkage continuously during sintering. TEM and SEM were used to characterize the microstructures
of the samples. The experimental results confirmed that Nb-doped BaTiO3 ceramics sintered at
1220°C for 2 h reached a larger densification of 97.0% relative density compared with 94.6% of pure
BaTiO3 ceramics sintered at 1265°C for 2 h, and Nb-doped BaTiO3 ceramics had a smaller grain size
(1.2μm) than that of pure BaTiO3 ceramics (2μm).
Stability of the Perovskite Structure in BSPT-Based Ferroelectric Ceramics
Authors: Chen Yi , Lan De Jun , Chen Qiang , Xiao Ding Quan , Yue Xi , Zhu Jian Guo
Published: March 2009

(1-x)BiScO3-xPbTiO3 (BSPT) based ferroelectric ceramics were prepared by conventional solid state process. X-ray diffraction analysis revealed that the morphotropic phase boundary (MPB) separating the rhombohedral and tetragonal phases for the BSPT system exited near x=0.62. It was found that the stability of perovskite structure of the BSPT system was improved with the increase of PbTiO3 content. For the 0.36BiScO3-0.64Pb1-ySryTiO3 (BSPST) system, because of higher amount of ionic bonding, the stability of perovskite structure for BSPT compounds containing strontium is larger than that of non-strontium compound.
Effect of Er3+ Doping on Crystallization of PbF2-SiO2 Based Bulk Xerogels
Authors: Zhou Li Hua , Luo Wen Qin , Wang Yuan Sheng
Published: March 2009

Transparent glass ceramics with composition of xErF3-10PbF2-90SiO2 (mol%, x=0, 1, 2, 3, 4)
were prepared by sol-gel method. The thermal behavior of the xerogels was investigated by DSC.
Through non-isothermal experiments, the apparent activation energy for the crystallization of β-PbF2
phase was evaluated by the Kissinger’s method and Chen’s method. XRD and TEM were carried out to
study the growth of β-PbF2 nanocrystals and the effect of Er3+ doping on it.
Shrinkages during from Liquid to Solid in Colloidal Forming
Authors: Yang Jin Long , Xi Xiao Qing , Huang Yong
Published: March 2009

The colloidal forming is an important process to prepare complex-shaped parts of ceramics, especially for industrialization of structure ceramics. It has been paid widely attention to by ceramic scientists, industries and governments in the past three decades. In 90’s, because the homogeneous green bodies were prepared using colloidal ways, many new colloidal forming processes were developed continuously such as gelcasting, DCC, TIF, colloidal vibration casting, colloidal injection moulding, HAS, and so on.. However, crackings of sintered bodies from colloidal ways have also often been occurred, especially for large size and solid parts of ceramics. In this paper, some important views about shrinkages from colloidal forming were discussed. The internal stresses in green bodies to prepare using colloidal forming resulted from the shrinkage of suspension during from liquid to solid. The shrinkage led to different cracks during sintering and/or debindering. Finally, it is put forward that the shrinkage from liquid to solid in colloidal froming have to be regarded in the future.
Indentation Fracture Toughness and Hardness of Solid Oxide Fuel Cell Electrolyte Material
Authors: Tekeli Süleyman , Gürü Metin
Published: March 2009

Yttria-stabilized cubic zirconia is well known the material that possesses high oxygen ionic
conductivity and chemical stability over wide ranges of temperature and oxygen partial pressure and
thus it is widely used as an oxygen sensor, thermal barrier and solid oxide fuel cell (SOFC) electrolyte.
In the present study, 8 mol% yttria-stabilized cubic zirconia with SiO2 addition up to 10 wt% was
studied with respect to the microstructure, fracture toughness and hardness. XRD results showed that
SiO2 had very limited solubility of 0.3 wt% in cubic zirconia. This suggests that only small part of
SiO2 dissolved in cubic zirconia and the rest of SiO2 segregated at grain boundaries and multiple
junctions. This glassy phase also wetted the zirconia grains and prevented the grain growth and the
formation of facetted grains. Both hardness and fracture toughness were measured using a Vickers
indenter. It is observed that the introduction of SiO2 decreased the hardness and increased the fracture
toughness of cubic zirconia. The hardness and fracture toughness also showed the same trend with
increasing SiO2 content.
Experimental Study of Micro Displacement Field of Microstate of Crack Tips of Ceramics Plasticized with Zirconia and Stabilized by Yttrium Oxide – Application of Digital Image Correlation Method Based on Analysis by Scanning Electron Microscope
Authors: Fu Yi , Ji Xin Hua , Qin Yu Wen
Published: March 2009

To study the deformation reaction of different metallurgical phases of the micron structure of
crack tips of zirconia ceramics in the loading state, the paper presents the micro experimental study based
on the digital correlated method of analysis by scanning electron microscope on the displacement field in
the micro areas of crack tip of the specimen of the Y2O3-ZrO2 toughened ceramic with the simple edge
notch beam method and under the action of three-point bending loads. First, SEM analyses was made on
the local area of the crack tip of a specimen’s polished surface before and after loads are applied to the
specimen, thus obtaining two SEM images, one before the application of the loads and another after the
load application, which contained their displacement information. Then, digital correlation calculations
were made between the gray scales of the pixels of the two images in order to obtain the microscopic
displacement fields of the crack tips in the microstate, thus unveiling the deformation modality and
displacement response of different metallurgical phases of the crack tips of zirconia ceramics when
subject to loads. The results of the studies will provide foundations and basis for further research in the
mechanical properties of the ceramics with Y2O3-ZrO2 and their relationship with the microstructures.
Wear Mechanism of Ceramic Microbeads as Grinding Media
Authors: Yue Ming , Yang Jin Long , Xi Xiao Qing
Published: March 2009

Ceramic microbeads are increasingly being used for wear applications, especially for milling
ultrafine powder. Research on friction and wear behavior of ceramics has become a more and more
important subject in the area. In this paper, three kinds of ceramic microbeads ––mullite-zirconia,
zirconium silicate and 95 alumina microbeads which were produced by Colloidal injection moulding
technique were tested by SRV high temperature friction and wear test system, which the working
condition of the ceramic microbeads as grinding media can be simulated to a certainty. The tests were
done under dry friction and water lubrication respectively. Then their worn surfaces were observed using
scanning electron microscopy. Through these experiments, the tribological properties and wear
mechanisms of the self-wearing ceramic microbeads were investigated.
Design of Ceramic Composite Based on the Impact Resistance and its Machining Application
Authors: Xu Chong Hai , Wang H.Y.
Published: March 2009

An optimum model for the compositional design of advanced ceramic composites is built based on the impact resistance. The relative impact modulus IM0 is defined as an index for the characterization of impact resistance of brittle ceramics. Computer aided optimum technique is used to get the optimum compositions of the material. Results show that the material can be expected to have the highest impact resistance which is nearly 86% higher than that of the pure alumina when the volume fraction of Al2O3, SiC and Ti(C,N) is 72.3%, 14.8% and 12.9%, respectively. An advanced SiC/Ti(C,N)/Al2O3 ceramic composite is then fabricated according to the optimum results. When used as cutting tools, its impact fracture resistance is approximately 71%-76% higher than that of the pure alumina ceramic in the machining of hardened carbon steel. The increment coincides well with that predicted directly from the optimum model. It suggests that the method is feasible in the design and fabrication of ceramic composites especially for machining application.
Serial Simulation of Ceramic Grain Growth Based on Ternary-Tree Structure and Space Partition
Authors: Ji Guo Li , Lin Y. , Yang Y.P. , Xiong Zhao Xian
Published: March 2009

An improved serial computation method is proposed for simulating ceramic grain growth at an
atomic scale. The data structure of a ternary tree is used to store orderly the atomic information and speed
up the editing of data. Combining with the idea of space partition, an index for space searching is
established to reduce the computation time. Simulation results demonstrate that the speed of the serial
computation is increased significantly and simulated images are in good agreement with micrographs of
practical ceramics. It is illustrated that kinetic exponents and fractal dimensions during the simulation of
grain growth are also reasonable in compare with quantitative analyses.
Effects of Ceramic Fillers on Light Reflectance and Arc Resistance of PTFE for Circuit Breaker
Authors: Park Hoy Yul , Kang Dong Pil , Lee Hee Woong , Park Seong Soo , Yoon Seog Young
Published: March 2009

This paper presents the effects of ceramic fillers on light reflectance and arc resistance of
PTFE(polytetrafluoroethylene) for nozzle of circuit breaker. In arc environment of a circuit breaker,
radiation generated from arcing is considered to play a key role in transport mechanism of arc energy to
the wall. Adding some ceramic fillers into PTFE material is expected to be efficient for improving the
endurance against arc radiation. In this experiment, three kinds of ceramic fillers for achieving good
endurance in the high temperature were used. Light reflectance and arc resistance of PTFE composites
were investigated. The arc resistance of PTFE composites increased with the amount of ceramic fillers.
The light reflectance of PTFE composites filled with ceramic fillers increased in the long wavelength
region and decreased largely in the short wavelength region in comparison with that of pure PTFE.
Microwave Dielectric Properties of (1-x)(Ca0.61Nd0.26)TiO3–x(Li0.5Sm0.5)TiO3
Authors: Wang Wei , Tang Zi Long , Zhang Zhong Tai
Published: March 2009

(1-x)(Ca0.61Nd0.26)TiO3-x(Li0.5Sm0.5)TiO3 (0.2 ≤ x ≤ 0.7) ceramics were prepared by solid-state
reaction method and the microwave dielectric properties of the resultant materials at different
(Li0.5Sm0.5)TiO3 contents were investigated. A single phase of perovskite in all samples was confirmed by
XRD patterns. With increasing (Li0.5Sm0.5)TiO3 content, Q×f value and dielectric constant (εr) decrease
slightly and the temperature coefficients of the resonant frequency (τf) of the specimens decreases
noticeably. The optimum parameters, i.e.,εr = 109, Q×f = 5259 GHz and τf = ~0 ppm/°C, for the
composition of 0.4(Ca0.61Nd0.26)TiO3-0.6(Li0.5Sm0.5)TiO3 was obtained when keep the calcination
temperature at 1250°C for 3 h.
Actuative Properties of CP Actuator Consisting of Polypyrrole Film and Solid Polymer Electrolyte
Authors: Kang Hye Ran , Jung Hae Do , Lee Jang Oo , Jo Nam Ju
Published: March 2009

Conducting polymer (CP) actuators undergo volumetric changes due to the movement of
dopant ions into the film during the electrical oxidation process. However, it may be an impediment for
practical use of polypyrrole actuator that polypyrrole usually requires electrolyte solution for actuation.
To solve this problem, solid polymer electrolyte(SPE) was introduced in CP actuator instead of
electrolyte solution. And PPy/SPE/PPy electroactive tri-layer actuator was prepared by the
electrochemical polymerization of pyrrole and the actuation characteristics were studied. An all-solid
actuator, consisting of two polypyrrole films and a solid polymer electrolyte based on polyurethane,
clearly showed a reversible displacement in an atmosphere when a voltage was applied.
Fine-Particle Lithium Iron Phosho-Olivine Synthesized by a Novel Modified Solid-State Reaction
Authors: Yang Rong , Song Xiao Ping , Pang Xiu Fen , Zhao Ming Shu , Wang Fei
Published: March 2009

In this paper, homogeneous and well-crystallized LiFePO4 was synthesized by a novel
modified solid-state reaction method following by heat treatment at relatively low temperature of 500°C
in Ar. No impurities are detected in the XRD patterns. The initial charge specific capacity and discharge
specific capacity reach 157.2mAhg-1 and 152.6mAhg-1 respectively at 20°C. Voltage plateaus at around
3.45V were observed in all the curves, indicating that the charge and discharge reaction proceeds as a
two-phase reaction. The initial charge specific capacity is 157.2mAhg-1 at 0.1C rate, i.e. 92% of the
theoretical capacity, and specific capacity decreases slightly after 100 circles at room temperature.
Crystallinity and Photoluminescence Properties of ZnO Films on Zn Buffer Layers Deposited by rf Magnetron Sputtering
Authors: Lee Chong Mu , Park Anna , Cho Young Joon , Kim Hyoun Woo , Lee Jae Gab
Published: March 2009

It is very desirable to grow ZnO epitaxial films on Si substrates since Si wafers with a high quality is available and their prices are quite low. Nevertheless, it is not easy to grow ZnO films epitaxially on Si substrates directly because of formation of an amorphous SiO2 layer at the interface of ZnO and Si. A Zn film and an undoped ZnO film were deposited sequentially on an (100) Si substrate by rf magnetron sputtering. The sample was annealed at 700°C in a nitrogen atmosphere. X-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM) analyses were performed to investigate the cristallinity and surface morphology of the ZnO film. According to the analysis results the crystallinity of a ZnO thin film deposited by rf magnetron sputtering is substantially improved by using a Zn buffer layer. The highest ZnO film quality is obtained with a 110nm thick Zn buffer layer. The surface roughness of the ZnO thin film increases as the Zn buffer layer thickness increases.
White Anodic Coatings on Aluminum Alloy with Low Ratio of Solar Absorptance to Infrared Emittance
Authors: Qin Wei , Cui Bo , Wu Xiao Hong , Jiang Zhao Hua
Published: March 2009

White anodic coatings are gained by growth in situ on the aluminum alloy. The coatings
possess stable optical properties, excellent adhesive power, low cost, stability in the space environment,
and so on, which can be widely used in the thermal control system of spacecrafts. In this article, the
developed Al2O3 thermal control coatings that had a low solar absorptance and a high infrared emittance
were gained in the electrolyte of sulfuric acid. The influences of various process parameters, such as
electrolyte temperature, current density, anodizing time, on the optical properties of the coatings were
investigated. AFM and XRD were used to characterize the microstructure of the coatings. Experimental
results show the anodic coatings could reach a solar absorptance value lower than 0.20 and an infrared
emittance higher than 0.80. Therefore, the coatings can be applied as important thermal control coatings
for space applications.
Preparation of Plank-Like BaTiO3 by Hydrothermal Soft Chemical Process from Layered Titanate Precursors
Authors: Zhou Long , Yu R. , Zhu K. , Yao J. , Xing X. , Wang D. , Wu X.
Published: March 2009

The influence of processing parameters on the morphology of hydrothermally derived BaTiO3 powders was investigated. Layered H2Ti3O7 with plank-like morphology were used as the Ti-precursor materials. The BaTiO3 powders were characterized by XRD and SEM. Lower Ba/Ti ratio is benefit for preparation of BaTiO3 particles which retains the morphology of the precursor. The BaTiO3 particles obtained at 200°C for 24h were large, uniform, and plank-like particles. Extending the hydrothermal temperature or the hydrothermal time does not help to synthesize BaTiO3 powders of large size and uniform morphology.
The Stability Range of Lead Oxide Compounds in Bi-System High Temperature Superconducting Materials
Authors: Li Ming Ya , Qi Xi Wei , Yu Zhi Yong , Han Zheng He
Published: March 2009

The stability range of lead oxide compounds Pb3Sr2.5Bi0.5Ca2CuOy (3321) phase in Bi-system
high temperature superconducting materials has been investigated. In this study (Bi,Pb)2Sr2Ca2Cu3Ox
(BSCCO) powder was heat treated in different oxygen partial pressure and different temperature. The
formation and the relative volume fraction of the 3321 phase were determined by X-ray diffraction. The
microstructure of the quenched pellets was observed using SEM. Experimental results show that the
stability range of the 3321 phase depends on both the temperature and oxygen partial pressure. A three
dimensional plot of relative 3321 phase formation was obtained for BSCCO powder in which the main
phase is (Bi,Pb)-2212 at different temperature and oxygen partial pressure.
Preparation and Characterization of Citrate Sol-Gel Derived Ba(Zr,Ti)O3 Ceramics with Al2O3 Addition
Authors: Pei Jing , Yue Zhen Xing , Zhao Fei , Gui Zhi Lun , Li Long Tu
Published: March 2009

The nano-sized Ba(Zr0.2Ti0.8)O3 powder was prepared by citrate sol-gel method. The crystal structure and the particle size of the powder were characterized by XRD. The morphology of calcined powder and the sintered ceramics was observed by TEM and SEM, respectively. The particle size of the powders calcined at 600oC is about 10 nm. The dense ceramics can be obtained at sintering temperature of 1220 oC, which is much lower than that of the powder prepared by the conventional solid method. The effects of Al2O3 additive on the sintering behavior, microstructure and dielectric properties of Ba(Zr0.2Ti0.8)O3 ceramics were also investigated.
Control of Shrinkage Behavior and Thermal Expansion Coefficient in BaTiO3-Added Ni Electrodes
Authors: Park Sang Hyun , Kang Jin Ho , Lee Seoung Soo , Jung Yeon Gil , Paik Ung Yu
Published: March 2009

In this study, shrinkage behavior and coefficient of thermal expansion (CTE) of novel
nickel (Ni) powder with an addition of dielectric material, BaTiO3, have been investigated to reduce
the large shrinkage mismatch between Ni electrode and dielectric material and to control the thermal
and/or residual stresses created by CTE mismatch in MLCCs (multilayer ceramic capacitors). For
which two kinds of Ni powders were used. The component of Ni powders is analyzed by XRF, and the
thermal behavior is measured by TG/DTA. The Ni and BaTiO3 powders were mixed with 9:1, 8:2,
and 7:3 volume ratios. The BaTiO3-added Ni green bodies were fabricated through cold isostatic
pressing, and then sintered to 1300°C in a reduction atmosphere. The shrinkage behavior with volume
ratio was checked during sintering from 700 to 1300°C with 300°C interval. The CTE was measured
in inert (argon) atmosphere with sintered samples. It is found that the shrinkage behavior and the CTE
of Ni electrode are dependent on the volume of BaTiO3 added. The particle size of Ni powder also
affects the microstructure and its sintering density, with less effect of its component.
Microstructure and Properties of Ni0.5Zn0.5Fe2O4-BaTiO3 Ceramic
Authors: Huang Ji Quan , Du Pi Yi , Han Gao Rong , Weng Wen Jian
Published: March 2009

Ni0.5Zn0.5Fe2O4-BaTiO3 composites were prepared by calcining Ni0.5Zn0.5Fe2O4 with BaTiO3 at
1220°C for 3 h. Both μ′ and μ″ of the composites decrease rapidly, but the cut-off frequency shifts to
higher level with increasing BaTiO3 content. The dielectric constant of the composites increases quickly
with increasing BaTiO3 content below 50% and keeps a high and nearly unchangeable value with
increasing BaTiO3 above 50%. The composites with BaTiO3 content between 20% and 40% are suitable
to use for the magneto-electric devices under high applied frequency due to its high permeability and low
dielectric loss.
Large Thermoelectric Response of Ti-Containing Perovskite Oxides
Authors: Ohta Hiromichi , Ohta Shingo , Koumoto Kunihito
Published: March 2009

Nb-content dependence of the thermoelectric figure of merit, ZT of SrTiO3 at high-temperature (1000 K) is clarified using heavily Nb-doped SrTiO3 epitaxial films, which were grown on (100)-face of LaAlO3 single crystal substrates by a pulsed-laser deposition. Carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity of Nb-doped SrTiO3 epitaxial films were experimentally evaluated at 1000 K with an aid of theoretical analysis. ZT reached 0.37 (20%-Nb-doped SrTiO3 epitaxial film) at 1000 K, which is the largest value among n-type oxide semiconductors ever reported.
Progress in Researches on the Layered Cobalt Oxides for Thermoelectric Devices
Authors: Liu Hong Quan , Song Ying , Wang Fu Ping
Published: March 2009

The layered cobalt oxides as thermoelectric (TE) materials are introduced in detail on their
developments, representative systems, some theories, unsolved problems and approaches for improving
performances. TE performances of the layered cobalt oxides are discussed from structures, doped
situations, processes and the dimensionless figure of merit. In contrast with other TE materials, the
layered cobalt oxides show many promising applications. The theory of Seebeck coefficient and hopping
conduction mechanism in the layered cobalt oxides are discussed. Heike formula explains that Seebeck
coefficient origins from electronic spin states and proportions of different value states of Co ion. An
unbalance of the spin and orbital degrees of freedom between Co3+ and Co4+ sites results in the large
Seebeck coefficient. On the basis of the Boltzmann transport equation, Seebeck coefficient is decided by
energy band structures. High state density near Fermi Energy band is responsible for the coexistence of
large Seebeck coefficient and high electrical conductivity. Hopping conduction mechanism found in
experiments is a main transport way of charge carriers at high temperature for the layered cobalt oxides.
Through different materials systems and theories analysis, unsolved problems and new approaches for
improving TE performances are put forward.
High Temperature Thermoelectric Properties of AgPb18+xSbTe20
Authors: Zhang Wen Bing , Chen Li Dong , Li Xiao Ya
Published: March 2009

Polycrystalline AgPb18+xSbTe20 compounds with different Pb contents (x=1-4) were prepared
by melting method and spark plasma sintering techniques. The crystal structure and chemical composition
were determined by XRD and EPMA. The thermal conductivity, electrical conductivity and Seebeck
coefficient were measured in the temperature range of 300-800K. The dimensionless thermoelectric
figure of merit (ZT) of AgPb18+xSbTe20 (x=1-4) increases in the whole temperature range of 300-750K
which is different to the pure lead telluride compound. The maximum ZT value reaches 1.03 at 800K.
Electrical Properties of P-Type Thermoelectric AgxBi0.5Sb1.5-xTe3 (x=0.05~0.4) Alloys Prepared by Spark Plasma Sintering
Authors: Cui J.L. , Yuan Y.L. , Hu B. , Yang W.
Published: March 2009

Thermoelectric Ag-Bi-Sb-Te alloys with the general formula AgxBi0.5Sb1.5-xTe3 (x =0.05∼0.4)
were prepared by spark plasma sintering and their electrical properties were examined. The alloys exhibit
large electrical conductivities in the whole temperature range, which are approximate 11.0 and 3.5 times
those of pseudo-binary Bi0.5Sb1.5Te3 alloy at room temperature and 558K, respectively. The highest
power factor value of 1.80×10-3 (W.K-2.m-1) is obtained for the material (x = 0.1) at the temperature of
412K, being about 2.4 times that of pseudo-binary alloy Bi0.5Sb1.5Te3 at the corresponding temperature.
Preparation of Sialon Using Fly Ash with High Content of Al2O3
Authors: Huang Zhao Hui , Tang Xun Hai , Liu Yan Gai , Fang Ming Hao
Published: March 2009

A new environment friendly method to synthesize sialon composites using fly ash with high content of Al2O3 by carbon-thermal reduction-nitridation was presented. The results showed that sintering temperature and the pressure of N2 gas are in favor of the nitrification synthesis of Sialon composites. When Samples wear buried in silicon powder and sintered at 1400°C under N2 atmosphere, Sialon (Si4Al2O2N6) had been synthesized.
SiC Platelets Synthesized by Powder-Heating Technique
Authors: Meng Yong Qiang , Bai Zhi Min , Dai Chang Hong , Zhang Bao Bao
Published: March 2009

A new method for producing silicon carbide platelets with low cost and high yield was
introduced. The silicon carbide platelets were synthesized by powder-heating techniques with carbon
black and SiO2 powder as raw materials and CoCl2 as catalyst. The starting mixtures were heated at a
temperature in the range of 1800-2000°C for the duration of about 2-4h to produce substantially
completely unagglomerated silicon carbide platelets with a thickness of 5-20μm and the average diameter
of 50-200μm. Compared to the conventional heating, the powder-heating technique is advantageous of
less investment on equipment, easy to manufacture and convenient to operate. Furthermore, it is very
suitable for realizing the scaled production because of the lower synthesizing temperature, shorter
reaction time and greater output.
Effect of Various Dispersants on the Gel-Casting of Silicon Nitride
Authors: Qian Li Peng , Hou Feng , Xu Ting Xian
Published: March 2009

A high solid loading of dispersed silicon nitride slurry was prepared with various dispersants,
which allowed a stable silicon nitride suspension with sintering additives (cordierite) in alkaline regions
to a solid content of 45 vol%. Gum arabic, PMAA-NH4, TMAH, PAA-NH4 and their composites were
selected as dispersants. The results suggested that the composite dispersant which was obtained using
PAA-NH4 and TMAH with the ratio in 4:1 was more effective in aqueous silicon nitride powder
suspensions system than simplex dispersant. The green bodies derived exhibited a mechanical strength as
high as 8.7MPa and SEM photos revealed that the green body also had a high homogeneity.
Features of Bonded Interface and Impedance and Power of PZT Transducer
Authors: Chen Xin , Zhong Z.H. , Wang Q.Y.
Published: March 2009

A series of experiments is carried out on the characteristics at the wedge bond interface. Bond lift-off characteristics are studied by using Scanning Electron Microscope with EDS-test. The characteristics of input impedance of PZT transducer are analyzed by the driving electric signal measured by Oscilloscope. Results show that the pattern of partially bonded material at the interface of ultrasonic wedge bonds exposed by peeling underdeveloped bonds simulates a torus with an unbonded central region. For the same machine variables, the input impedance and transforming power of the first wedge bond are greater than that of the second wedge bond. Some conclusions drawn by analyzing the input impedance and the power of PZT consist with the results gotten by testing microstructures at the interface.
Micromechanics on Spherical Contact with Roughness
Authors: Jeon J.S. , Hyun S. , Kim Young Shin
Published: March 2009

Finite-element methods are used to study non-adhesive, frictionless rough contact of
elastic and plastic solids. Roughness on the contact surfaces is realized by self-affine fractal. True
contact area between spherical rough surfaces and flat rigid surfaces rises in power law as the
external normal load increases. The power exponent is sensitive to surface roughness as well as the
curvature of spherical geometry. Surface contact pressures are analyzed and compared for elastic
and plastic solids. The distribution of local contact pressure is significantly dependent on the
surface roughness and the yield stress of plastic solids.
Digital Precision Measuring of Spiral Bevel Gear Based on CAD/CAM/CMM
Authors: Pan Wei Min , Li Ji Shun , Lei Y.
Published: March 2009

Precision measuring techniques have been developed interdependently with the techniques of design and manufacturing in the history. Computer aided inspection plays a very important role in modern manufacturing industry. On account of the CMM (Coordinates Measurement Machine) being applied widely and the precision model inspection concept coming true, it is possible to implement the digital inspection of the spiral bevel gear on the CMM. In this paper the framework of the spiral bevel gear digital inspection based on the integration of CAD/CAM/CMM is put forward. The key techniques of the scheme are investigated, which consist of exact modeling of spiral bevel gear based on manufacturing process, datum matching of CAD model and CMM inspection, CMM Inspection path planning, reconstruction of the tooth surface based on the CMM inspection results, Analysis of the deviation between the real gear tooth and CAD model, adjusting strategy of machining parameters.
Spinning- Inflated-Ballonet Polishing Tool and its Application in Curved Surface Polishing
Authors: Ji Shi Ming , Zhang Li , Zhang Xian , Wan Yue Hua , He Hai Ping , Yuan Ju Long , Yuan Qiao Ling , Jin Ming Sheng
Published: March 2009

In this paper, a novel spinning-inflated-ballonet polishing tool for curved surface of
mould is proposed. The head of the tool is a spherical spinning-inflated-ballonet whose inner air
pressure can be controlled on-line and the head surface is covered with a suitable polishing cloth.
The head can be rotated in high speed driven by an electromotor or high pressure airflow and its
rotating speed can be adjusted. The flexibility of the head, the polishing force in radial direction and
the contact area between the head surface and the curved surface of the work-piece can be
controlled by adjusting the feeding deepness and ballonet pressure of the tool. The structure and the
polishing mechanism of the novel polishing tool are introduced. The application of robot polishing
system based on the novel polishing tool also is discussed. Finally the polishing control strategy of
curved surface is researched.
The Mechanism and Feasibility of Self-Assembly with Capillary Force
Authors: Zhao D.P. , Wu D. , Chen K.
Published: March 2009

This paper introduces a fluidic technique based on patterned shapes of hydrophobic
self-assembly monolayers (SAMs) and capillary forces to self-assemble micro-parts onto substrates.
Self-assembly is defined as a spontaneous process that occurs in a statistical, non-guided fashion.
More specifically, the fluidic self-assembly with capillary force is driven by the gradient in
interfacial free energy when a micro-part approaches a substrate binding site. In this paper, the
mechanism of self-assembly with capillary forces is proposed. The hydrophobic-hydrophilic
material system between the binding sites and micro-parts is then simulated. Finally, the surface
energy of a self-assembling system in the liquid phase under different conditions is calculated. The
results show that shift, twist, lift and tilts displacements are detected to be rather uncritical and the
system turns out to be rather stiff with respect to such displacements. The theoretical result is
supported by the experiments and gives quantitive explanations why and how the capillary force
works in the self-assembly process.
Research on Flow in Microchannels with Lotus Effect Coating by Molecular Dynamics Simulation
Authors: Jia K. , Zhang H.H. , Fan X.Q. , Jiang X.P. , Liu S.
Published: March 2009

In this paper, nonequilibrim molecular dynamics (NEMD) was used to simulate liquid flow in microchannels with ‘lotus effect’ coating. Without considering atomic structure and long-range interaction, we have been dedicated in establishing a two-dimensional geometric model based on the coating and studying the behavior of liquid near the inner surfaces of ‘lotus effect’ microchannels. The shape of a single pattern in the coating and the thickness of one microchannel were varied to study the influences of these parameters on velocity profile of liquid in the flow direction, the maximum of this velocity, and its position perpendicular to flow direction. The proper conditions which made the velocity slip of liquid near the boundary layer of microchannels maximum and liquid move most fast were decided.
Improved Micro-EDM Miniaturized Device Using Differential Reciprocating Driving Method
Authors: Tang Y.J. , Wang Zhen Long , Hu Q. , Zhao W.S.
Published: March 2009

A miniaturized Electrical Discharge Machine (EDM) device based on ultrasonic motor has been developed to machine micro-holes in narrow space. In this mechanism, the electrode is driven without need of electrode holder, so that the mass and inertia of slider are greatly smaller, and feeding frequency of electrode can be raised compared to the conventional miniaturized EDM devices. This is a significant improvement that the electrode’s driving means varies from plane driving to line driving. Because of its advantage of compact size, the miniaturized EDM device can be fixed on robot. Differential Reciprocating Driving Method (DRDM) for EDM electrode is proposed. Feeding resolution of electrode reaches 0.5μm in stepping style, while resolution reaches 40nm in differential reciprocating style, and all above characteristics create preconditions for micro EDM machining. The holes with figures of Φ90μm inclined circle and inclined Y have been machined.
Three-Dimensional Simulation of Micro Air Vehicles with Low-Aspect-Ratio Wings
Authors: Zhang Xiao Quan , Tian L.
Published: March 2009

Micro Air Vehicles (MAVs) are catching more and more attentions for their broad application in civilian and military fields. Since the theories on the aerodynamics of low Reynolds number are not maturely presented and the wind-tunnel experiments cost long periods and great expenses. The numerical simulation based on computational fluid dynamics (CFD) is a good method to choose. Through three-dimensional simulation of the wings, the aerodynamic characteristics of the flows around MAVs can be easily obtained. The tip vortices produced around low-Reynolds-number and low-aspect-ratio wings can increase the lift and stall angles. The result of numerical simulation can be used as references of theory analysis and wind-tunnel experiments.
Ultraprecision Ductile Grinding of Optical Glass Using Super Abrasive Diamond Wheel
Authors: Zhao Qing Liang , Brinksmeier Ekkard , Riemer Otmann , Rickens Kai
Published: March 2009

In this paper, a novel conditioning technique features using copper bonded diamond
grinding wheels of 91μm grain size assisted with ELID (electrolytic in-process dressing) as a
conditioner to precisely and effectively condition nickel electroplated monolayer coarse-grained
diamond grinding wheels of 151μm grain size was firstly developed. Under optimised conditioning
parameters, the super abrasive diamond wheel was well conditioned in terms of a minimized run-out
error and flattened diamond grain surfaces of constant peripheral envelope, with the conditioning
force monitored by a force transducer as well as the modified wheel surface status in-situ monitored
by a coaxial optical distance measurement system. Finally the grinding experiment on BK7 was
conducted using the well conditioned wheel with the corresponding surface morphology and
subsurface damage measured by AFM (atomic force microscope) and SEM (scanning electron
microscope) respectively. The experimental result shows that the newly developed conditioning
technique is applicable and feasible to ductile grinding optical glass featuring nano scale surface
roughness, indicating a prospect of introducing super abrasive diamond wheels into ductile
machining of brittle materials.
Modeling of Piezoelectric Actuator Based Nano-Positioning System Using Multi-Polynomial Regression with C1 Continuity
Authors: Tse S. , Gao Y.
Published: March 2009

For nano-positioning systems with piezoelectric actuators used for dynamic grinding control, sinusoidal command signals will used and will give additional problems compared with the commonly used step signals because of the hysteresis effects, which require a good modeling approach. The proposed approach of multiple polynomial regression with first order continuity gives a relative modeling error of 2.65%. The method reduces the error by 26.3-80.2% in comparison with the methods using the single, dual, and multiple polynomial regression with zero order continuity.
Experimental Study on High Speed Milling of γ-TiAl Alloy
Authors: Ge Ying Fei , Fu Yu Can , Xu Jiu Hua
Published: March 2009

This paper deals with the milling machinability of gamma titanium aluminide at speeds
of 60-240m/min. The results showed that surface roughness was less than Ra0.44μm at all cutting
speeds used in the tests even when the tool wear reached VB0.2mm. The milling forces increased
slightly with increasing cutting speed but increased rapidly with the elevated flank wear value
especially for the Fy component. Compared to those of titanium alloy TA15, the milling forces of
γ-TiAl were 190%, 180% and 200% greater for Fx, Fy and Fz respectively under the same
machining conditions. Workpiece surface has a maximum microhardness of approximately
600HV0.100, and the depth of maximum hardened layer was confined to 180μm below the surface.
When cut with TiAlN coated carbide tool, tool life was 35 min which was only about 1/2 of that for
titanium alloy TA15.
FE Simulation of Diamond Turning with Different Friction Coefficients
Authors: Wang H.X. , Wang Bo , Wang Jing He
Published: March 2009

In this work, a coupled thermo-mechanical plane-strain large deformation FE cutting model is developed to simulate diamond turning based on the updated Lagrangian formulation. As expected, the effects of friction coefficient on cutting forces, chip deformation, cutting temperature, flow stresses and shearing angle are investigated by FE simulations. The simulated results can be adopted as a reference to select the reasonable friction coefficient in diamond turning process.
On the Taper Interference Fit in the HSK Spindle/Toolholder Interface
Authors: Zhang Song , Ai Xing , Li Jian Feng , Fu Xiu Li
Published: March 2009

The HSK spindle/toolholder interface belongs to the complicated nonlinear contact
problem caused by taper interference fit. The experiment and the traditional Lame's equation are all
not suited for analyzing the contact stress distribution and deformation in the spindle/toolholder
interface. In this paper, the contact stress distribution and the deformation of the HSK-A63
spindle/toolholder interface caused by the taper interference fit were precisely simulated by means
of the finite element method. The simulated results showed that the toolholder shank was in partial
contact with the spindle bore, the interference specified by ISO was not enough for the high-speed
machining and larger interference should be introduced.