bluuebunny/crossref_metadata_2025 huggingface dataset:
Degradation of Lead Zirconate Titanate Piezoelectric Ceramics Induced by Water and AC Voltages
Authors: Xiang Wang , Chen Wan Ping , You Wen Chao , Chan Helen Lai Wah , Li Long Tu
Published: March 2009

A comparison experiment was conducted in which some lead zirconate titanate (PZT) piezoelectric ceramic rings were simply immersed in a 0.01 M NaOH solution while other PZT rings were immersed in the solution with a 50 Hz AC voltage applied between the electrodes of the rings and a counter electrode in the solution. Though the simple immersion showed no noticeable influence on the PZT rings, those PZT rings treated with the application of the AC voltage were obviously degraded in their piezoelectric properties. It was proposed that the degradation resulted from the collaborated reactions of atomic hydrogen and oxygen generated in the AC voltage-induced electrolysis of water. Water may be an important origin for degradation of piezoelectric ceramic devices operating under AC voltages.
A Study on SrCe0.9Y0.1O3-α Synthesized by Solid State Reaction and the Liquid Citrate Method
Authors: Feng Jun , Gu Jing Hua , Zhang Yue , Yang Wei Shen
Published: March 2009

The solid-state reaction method and the liquid citrate method were used respectively to
synthesize SrCe0.9Y0.1O3-α (SCY10) powders. SCY10 membranes were prepared from each kind of the
powders by sintering at 1450°C for 10 hours. XRD was employed to examine the phase of the powders
and the membranes. The microstructure of the membranes was observed with SEM. The sintering ability
and electrical properties of the membranes were investigated. The results indicate that the membrane
prepared from SCY10 powder synthesized by the liquid citrate method has higher relative density and
nearly the same conductivity, compared with the membrane prepared from SCY10 powder synthesized by
solid-state reaction.
Limiting Current Oxygen Sensors with LSF as Dense Diffusion Barrier
Authors: Wang Ling , Li Fu Shen , Zhou Hui Zhu , Xia Hui , Yang Mei , Li Li Fen
Published: March 2009

A new type of limiting current oxygen sensor which uses yttria (8%mol) stabilized zirconia (YSZ) as oxygen ion conducting solid electrolytes and dense La0.8Sr0.2FeO3 (LSF) as diffusion barrier was developed successfully. The oxygen sensor shows excellent performance at oxygen concentrations range of from 0 to 21%. The advantages of the sensor are simple construction, low cost and potential long term stability.
Microstructure and Electrical Conductivity of Ni-YSZ Cermets Prepared by Combustion Synthesis Method
Authors: Lin Tie Song , Jia De Chang , Sun Ke Ning
Published: March 2009

Ni-YSZ cermets were prepared by combustion synthesis of Y(NO3)3, Zr(NO3)4, Ni(NO3)2 and
urea followed by hydrogen reduction at 800°C. The microstructure and electrical conductivity of Ni-YSZ
cermets were investigated as contrasted to those of the cermets with the same Ni contents prepared by
mechanically mixing method. The cermets prepared by combustion synthesis method had better
homogeneity of Ni distributed in YSZ than those prepared by mechanically mixed method; thus, both Ni
and YSZ phases formed, to a certain extent, a continuous network structure. The electrical conductivity of
the cermets prepared by combustion synthesis method was always better than that obtained with the
samples prepared by mechanically mixed method.
Preparation and Characterization of Sm1-xSrxCoO3 Ceramics by the Gelcasting Process
Authors: Cheng Ji Gui , Shi Ping , Zhong Hong Hai , Wang Bu Mei
Published: March 2009

Perovskite Sm1-xSrxCoO3 ceramics have been successfully prepared by gelcasting from oxides
and carbonate powders, which were characterized by sintering the gels cast from a suspension of
low-solubility metallic oxide precursors and organic monomers. The porosity, pore size, microstructure
and electrical conductivity of the obtained Sm1-xSrxCoO3 ceramics were also investigated. It has been
shown that single Sm1-xSrxCoO3 perovskite phase forms at a relatively low calcination temperature of
1000°C. Especially, porous Sm1-xSrxCoO3 ceramics with homogeneous microstructure can be obtained by
controlling sintering process of the gelcasts. In addition, the Sm1-xSrxCoO3 ceramics show good electrical
conductivity, which can meet the demand for solid oxide fuel cell cathode application.
Investigation on Structure and Electrochemical Properties of Li[Ni1/3Co1/3Mn1/3]O2 for Lithium Ion Batteries
Authors: Shi Xiu Juan , Zheng Yong Ping , Kang Fei Yu , Li Xin Lu , Shen Wan Ci
Published: March 2009

Cathode material Li[Ni1/3Co1/3Mn1/3]O2 for lithium-ion batteries with layered hexagonal
structure was successfully synthesized in sol-gel way. The influences of calcination temperature (from
700° to 1000°C) on the structure and electrochemical behaviors of Li[Ni1/3Co1/3Mn1/3]O2 were
extensively investigated. The results of XRD show that all samples are isostructural with α-NaFeO2 with
a space group R-3m. XPS analysis shows that the oxidation states of Co and Mn were Co3+ and Mn4+
respectively, while Ni exists as Ni2+ and Ni3+. The charge-discharge experiments show that the sample
calcined at 850°C delivers 194.8mAh/g in the first cycle at C/5 rate in 2.5-4.3V potential range.
Preparation of Spherical Spinel LiMn2O4 Cathode Material for Lithium Ion Batteries
Authors: Pu Wei Hua , He Xiang Ming , Zhang Guo Yun , Jiang Chang Yin , Wan Chun Rong , Zhang Shi Chao
Published: March 2009

A novel process was proposed for preparing spinel LiMn2O4 with spherical particles from cheap materials of MnSO4, NaOH, NH3•H2O and LiOH. Its successful preparation started with a carefully controlled crystallization of Mn3O4, leading to the spherical shape of its particles and a high tap density. The mixture of Mn3O4 and LiOH was sintered to produce LiMn2O4 with spherical particle size retention. The spherical particles of spinel LiMn2O4 were of excellent fluidity and dispersivity, and had tap density as high as 2.14 g cm-3 and the initial discharge capacity reaching 128 mAh g-1. Its 15th cycle capacity kept to be 125 mAh g-1.
Novel AC-MO-CSC Anode for Direct Methanol Low Temperature Ceramic Fuel Cells
Authors: Feng B. , Wang Cheng Yang , Zhu Bin
Published: March 2009

Low temperature (300 to 650 °C) ceramic fuel cells (LTCFCs) were developed by using novel
AC-MO-CSC anode material based on activated carbon (AC), transition metal oxides (MO) and ceria-salt
composites (CSC). The activated carbon was first used to improve the characters of anode materials,
especially to enhance the anode catalytic activity for liquid hydrocarbon fuels, e.g., methanol. The
microstructure, conductivity and electrochemical properties of anode materials were investigated as
functions of the activated carbon. Using the anode materials, maximum power density of 0.2 W cm-2 was
achieved for fuel cells directly operating methanol at 600 °C.
LiNiO2 Thin Films Fabricated by Diffusion of Li on Ni Tapes
Authors: Kim Cheol Jin , Ahn In Sup , Cho Kwon Koo , Lee Sung Gap , Chung Jun Ki
Published: March 2009

LiNiO2 thin films for the application of cathode of the rechargeable battery were fabricated by
Li ion diffusion on the surface oxidized NiO layer. Bi-axially textured Ni-tapes with 50 ~ 80 μm thickness
were fabricated using cold rolling and annealing of Ni-rod prepared by cold isostatic pressing of Ni
powder. Surface oxidation of Ni-tapes were conducted using tube furnace or line-focused infrared heater
at 700 °C for 150 sec in flowing oxygen atmosphere, resulted in NiO layer with thickness of 400 and 800
μm, respectively. After Li was deposited on the NiO layer by thermal evaporation, LiNiO2 was formed by
Li diffusion through the NiO layer during subsequent heat treatment using IR heater with various heat
treatment conditions. IR-heating resulted in the smoother surface and finer grain size of NiO and LiNiO2
layer compared to the tube-furnace heating. The average grain size of LiNiO2 layer was 0.5~1 μm, which
is much smaller than that of sol-gel processed LiNiO2. The reacted LiNiO2 region showed homogeneous
composition throughout the thickness and did not show any noticeable defects frequently found in the
solid state reacted LiNiO2, but crack and delamination between the reacted LiNiO2 and Ni occurred as the
reaction time increased above 4hrs.
The Effect of Silicate Layers on Electrochemical Properties in Nanocomposite Solid Polymer Electrolytes
Authors: Jeong Soo Kyeong , Jo Nam Ju
Published: March 2009

Nanocomposite solid polymer electrolytes (NSPEs) based on poly (vinylidene fluoride) (PVDF)
were prepared by dispersing organically modified clay (Cloisite®30B, C30B) consisted of silicate layers
in the polymer matrix. And ion conductive properties were investigated in relation to dispersed condition
of silicate layers and structural changes of nanocomposites. The characterizations of PVDF/C30B
nanocomposites with various C30B contents were analyzed by XRD, DSC, DMA and SEM. In order to
confirm the ion conductive properties of NSPEs added to lithium trifluoromethansulfonate (LiCF3SO3) at
room temperature, ac impedance analyzer and FT-IR spectrometer were used in this study. The degree of
C30B dispersion in PVDF and the degree of crystallinity of PVDF/C30B nanocomposites showed the
decrease with C30B contents. As a result, high ionic conductivity was observed in the sample added to
3wt% clay in the polymer matrix and the maximum conductivity was 9x10-4S/cm.
Poly(Acrylonitrile-Methyl Methacrylate) Based Microporous Gel Electrolyte for Li-Ion Battery
Authors: Pu Wei Hua , He Xiang Ming , Wang Li , Jiang Chang Yin , Wan Chun Rong , Zhang Shi Chao
Published: March 2009

Preparation and performance of poly(acrylonitrile-methylmethacrylate) based microporous
gel electrolyte for Li-ion batteries were studied. The poly(acrylonitrile-methyl methacrylate (P(AMMA))
was synthesized by suspension polymerization, and poly(acrylonitrile-methyl methacrylate) microporous
polymer membrane with 0.03~0.1mm was prepared by phase inversion technique. The gel electrolyte was
obtained by putting the P(AMMA) microporous polymer membrane in a liquid electrolyte, which was a
solution of 1.0 M LiPF6 dissolved in a 1:1 (v/v) mixture of ethylene carbonate (EC) and diethylene
carbonate (DEC, and heated at 60°C for 2 hours. The microporous gel electrolyte gelled with 325 wt.% of
liquid electrolyte vs. the dried membrane presented an ionic conductivity of 7.52 × 10-4 S/cm at 25°C. The
coin test battery with the microporous gel electrolyte showed a good cycling performance. The discharge
capacity retention was above 88% at 0.1C rate at the 50th cycle.
Dependence of Electrical and Optical Properties of the Al Doped ZnO for Transparent Conductors Deposited by rf–Magnetron Sputtering on the O2/Ar Gas Flow Ratio
Authors: Lee Chong Mu , Yim Keun Bin , Kim Choong Mo
Published: March 2009

ZnO:Al thin films were deposited on sapphire(001) substrates by RF magnetron sputtering.
Effects of the O2/Ar flow ratio in the sputtering process on the crystallinity, surface roughness, carrier
concentration, carrier mobility, and optical properties of the films were investigated. AFM analysis
results show that the surface roughness is lowest at the O2/Ar flow ratio of 0.5 and tends to increase owing
to the increase of the grain size as the O2/Ar flow ratio increases further than 0.5. According to the Hall
measurement results the resistivity increases as the O2/Ar flow ratio increases. The transmittance of the
film tends to increase as the O2/Ar gas flow ratio increases up to 0.5 but it nearly does not change with
continued increases in the O2/Ar flow ratio. Considering the effects of the the O2/Ar flow ratio on the
surface roughness, electrical resistivity and transmittance properties of the ZnO:Al film the optimum
O2/Ar flow ratio is 0.5 in the RF magnetron sputter deposition of the ZnO:Al film.
Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing
Authors: Yang Chun , Zhang Jun Ying , Feng Hai Bing , Hao Wei Chang , Wang Tian Min
Published: March 2009

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.
Microstructure and Electrical Properties of ZnO-Pr6O11-Dy2O3-Based Varistor Ceramics Doped with La2O3
Authors: Cai Jing Nan , Lin Yuan Hua , Zhao Rong Juan , Nan Ce Wen , He Jin Liang
Published: March 2009

ZnO-Pr6O11-Dy2O3-based varistor ceramics doped with 0~1.5 mol% La2O3 were fabricated by
a conventional ceramic method. All the samples were sintered at 1350 oCfor 2 h. The phase composition
and microstructure of the ceramic samples have been investigated by XRD, SEM and EDS. The results of
SEM micrographs indicated that the La2O3 additives can promote ZnO grain’s growth, and the rare earth
elements dispersed mainly in the intergranular phase observed by EDS. The electrical properties of the
samples determined by the V-I curves revealed that the breakdown voltage of samples decreases from 508
V/mm to about 100 V/mm with the increase of La2O3, and the nonlinear exponent also decreases from
20.2 to 13.2. The typical leakage current is about 10.2 μA for the sample doped with 0.5 mol% La2O3.
Preferred Orientation Growth of Ba0.6Sr0.4TiO3 Thin Films with Epitaxial MgO Buffer Layer on Si(100) Substrate
Authors: Ma Xue Feng , Wang Shu Bin , Zhang Yue
Published: March 2009

Epitaxial MgO thin films were deposited on Si(100) substrate by atmospheric-pressure metalorganic chemical vapor deposition for using as buffer layers. Ba0.6Sr0.4TiO3 thin films were prepared on MgO/Si(100) substrate by sol-gel technique. The independence of crystallinity on annealing temperature was investigated. The Ba0.6Sr0.4TiO3 (BST) thin films are crystallized in preferential (100) orientation after post-deposition annealing at 850°C and 950°C for 2h in air, respectively. Rutherford backscattering spectroscopy analysis confirmed that both the BST and MgO films have stoichiometric composition.
Reliability of Ba(Zr0.1Ti0.9)O3 Ferroelectric Thin Films under Various Frequencies for Nonvolatile Memory Application
Authors: Chen Kai Huang , Cheng Chien Chuan , Chen Ying Chung , Chang Ting Chang
Published: March 2009

In this study, ferroelectric thin films of Ba(Zr0.1Ti0.9)O3 were successfully deposited on Pt/Ti/SiO2/Si substrate under the optimal rf magnetron sputtering parameters, and their electrical and ferroelectric characteristics were investigated. The MFMIS structure of Al/Ba(Zr0.1Ti0.9)O3/ Pt/Ti/SiO2/Si was proposed in order to be applied as NDRO FRAM applications. From the experimental results obtained, the dielectric constant and the leakage current density of BZT films were about 200 and 1×10-9A/cm2, respectively, under the electrical field of 1 MV/cm. Besides, the saturation polarization and coercive field of Ba(Zr0.1Ti0.9)O3 films were found to be 4 μC/cm2 and 25 kV/cm, respectively, as the frequency of 103 Hz was applied. The variations of saturation polarization and coercive filed of films under various frequencies ranging form 102 to 106 Hz were also discussed.
Modification of Thick-Film Conductors Used in IP Technology for Reduction of Warpage during Co-Firing of LTCC (Low Temperature Co-Fired Ceramic) Modules
Authors: Birol Hansu , Maeder Thomas , Ryser Peter
Published: March 2009

LTCC technology offers low temperature firing (<900 °C) of a materials system, which is based on LTCC sheets/tapes and (ideally) compatible thick-film components. Screen-printed materials on LTCC tapes, such as conductor, resistor, inductor thick-films are co-fired (simultaneously fired), providing a highly-functional package. This comes along with additional benefits such as ease of LTCC tape structuring, fabrication of hermetic and complex 3-D structures, etc. The major difficulty encountered arises from the differential shrinkage rate of LTCC tape and thick-film components, which has to be avoided for fabrication of warpage-free, flat surfaces that is vital for membranes, beams, etc. Therefore the goal of this study is the reduction of deformation, by matching the shrinkage rate of conductor with that of LTCC, which is achieved by mixing the commercially-available paste with selected additives.
The Optical and Electrical Properties of Antimony-Doped Tin Oxide Transparent Conducting Thin Films Prepared by Sol-Gel Dip-Coating Technique
Authors: Zhang Dao Li , Deng Zhi Bing , Zhang Jian Bing , Chen Liang Yan
Published: March 2009

Antimony-doped tin oxide (ATO) transparent conducting thin films were prepared by
sol-gel dip-coating technique in the alcohol solution of metal salts of tin (II) chloride dehydrate and
antimony tri-chloride. Usual glass slides (25×76×1mm3) were used as the substrates. As-prepared thin
films were dried at temperature of 343K and annealed at temperatures of 673~823K. Their optical
properties were analyzed by Hitachi U-3310 spectrophotometer. The good optical transmission of the
ATO thin films has been obtained as high as 80%-90% in visible region by the optimization of
deposition conditions, but decreased substantially in IR region. From the X-ray diffraction (XRD)
measurements, it showed that ATO films had the similar structures with the pure tin oxide films, i.e.
tetragonal rutile structure, despite of some rhombic SnO crystals. We analyzed the transmittance in
the visible region depending on the vary Sb doped level, temperature, and dip-coating times. The
sheet resistance of the investigated thin films was determined by four-probe method, showing that it
was about 85-1009/□, which decreased with the increase of antimony doped concentration.
Study of In2O3 Thin Films Prepared on TiN Substrates Using a Triethylindium and Oxygen Mixture
Authors: Kim Hyoun Woo , Myung Ju Hyun
Published: March 2009

Indium oxide (In2O3) films was deposited on TiN substrates by the metal organic chemical
vapor deposition technique using a triethylindium and oxygen mixture. The films deposited at 250-350°C
were polycrystalline, while that deposited at 200°C was close to amorphous. XRD and SEM analyses
indicated that the films grown at 350°C had grained structures with the (222) preferred orientation.
Effect of Raw Materials on the Thermal Conductivity and Microstructure of Aluminum Nitride
Authors: Liu Zhi Ping , Zheng Hong Yu , Zhang Jin Li , Jin Zheng Guo
Published: March 2009

High thermal conductivity, along with good electrical and mechanical properties, makes
aluminum nitride a very promising material for electronic packaging and substrates. Much work has been
reported on the influence of additions and sintering aids on densification and thermal conductivity. In this
paper, the influence of raw materials on the sintering behavior and thermal conductivity characteristics of
pressureless-sintered AlN has been investigated. The highest thermal conductivity is 248W/m.K.
SrTiO3 Based Dual-Functional Ceramics with Nano-Additives
Authors: Ji Hui Ming , Liu Xiao Chuan , Lv Ying , Li Cui Xia , Chen Xiao Dong
Published: March 2009

The electrical properties and microstructures of SrTiO3 based voltage-sensing and dielectric dual-functional ceramics with nanometer donor and acceptor additives were studied. The La2O3 nanopowders and MnO-SiO2-Al2O3 (or CuO-SiO2-Al2O3) nano-composite powders were incorporated into SrTiO3 as donor, acceptor and liquid-phase sintering aids. Then semiconducting SrTiO3-based ceramics were sintered at 1360-1440oC for 2 h in a reducing atmosphere. The effects of the nanometer donor and acceptor additives and the sintering temperature on the electrical properties and microstructures of materials were discussed. The results showed that SrTiO3-based varistor ceramics with 1.1 mol% La2O3 and 0.1 mol% MnO nano-additives sintered at 1360-1420oC in graphite and N2 reducing atmosphere have excellent voltage-sensing and dielectric characteristics. The varistor voltage ranges from 2.3 to 5.3 V/mm, the nonlinear coefficient from 3.0 to 3.8, and the dielectric constant from 215,600 to 413,000.
Synthesis and Lattice Thermal Conductivity of Double Atoms Filling p-Type CamCenFexCo4-xSb12 Compounds
Authors: Li Han , Tang Xin Feng , Liu Tao Xiang , Song Chen , Zhang Qing Jie
Published: March 2009

Single-phase double atoms filling skutterudite compounds were synthesized by using melting reaction method. The effects of double atoms filling on the structure and lattice thermal conductivity of skutterudite compounds were investigated. The results of Rietveld refinement indicate that CamCenFexCo4-xSb12 compounds possess skutterudite structure and the Sb-icosahedron voids have been partially filled with filling atoms. With the same filling fraction, the lattice thermal conductivity of CamCenFexCo4-xSb12 is smaller than that of CamFexCo4-xSb12 and CenFexCo4-xSb12, furthermore, when the total filling fraction (m+n) is about 0.3 and respective filling fraction of Ca and Ce are approximately equal, the lattice thermal conductivity is the least.
Heat to Electricity Conversion Efficiency Measurement for Thermoelectric Unicouple
Authors: Wang Qing Hua , Zhang Jian Zhong , Zhang Li Li , Wang Ze Shen
Published: March 2009

The conversion efficiency of heat to electricity is the basic parameter of thermoelectric element,
thermoelectric unicouple and thermoelectric devices. In principle, the heat to electricity conversion
efficiency of thermoelectric element has been defined as the electrical output power of the element
divided by its thermal input power. Due to the heat loss by convection and radiation heat transfer the test
result of the heat to electricity conversion efficiency has a large errors. The authors present a test method
for heat to electricity conversion efficiency of thermoelectric unicouple. The thermal input power of
thermoelectric unicouple has been divided into the electrical output power plus thermal output power out
of the cold end of the unicouple. The later has been determined by a thermoelectric thermal power meter.
The method avoids the difficulties to measure the input thermal power into the hot side of the unicouple,
so that the convection and radiation heat lose out of the unicouple side can be ignored. Owing to Seebeck
Coefficient of the thermoelectric semiconductor materials could be many times of the metals, the
thermoelectric thermal power meter has high sensitivity, so that high test precision could be gained in test
for conversion efficiency of thermoelectric unicouple. The paper presents some test results for heat to
electricity conversion efficiency of thermoelectric unicouple, and discusses about the factors which affect
the test results.
Preparation and Dielectric Properties of the Nb and Co Doped Barium Titanate by Sol-Gel Auto-Ignition Synthesis Process
Authors: Zhang Wen Feng , Yan Qing Zhi , Su Xin Tai , Ge Chang Chun
Published: March 2009

The Nb and Co doped barium titanate was synthesized by sol-gel auto-ignition synthesis process (abbreviated SAS) and compared with the doped powder of the same composition prepared by conventional ball milling process. The phase structure, morphology of the two as-obtained powders and correlative dielectric properties of sintered BaTiO3-based ceramics were measured. The XRD analysis demonstrated that the SAS powder was the Ba(M0.047Ti0.953)O3(M=Nb, Co) solid solution based on BaTiO3; it further suggested that Nb and Co cations could replace the Ti ions and reach reciprocal balance of acceptors and donors during the decomposition step of the organic fuel by igniting the dried gel. TEM observation showed that the Ba(M0.047Ti0.953)O3(M=Nb, Co) particles were spherical with the size ranged from 30 to 110nm. Furthermore, it was found that the value of the Curie temperature of both the doped powders was being lowered in comparison with pure BaTiO3 (Tc≈128°C ); and the dielectric constant at room temperature of the SAS powder was 5840, which was much higher than that of the conventional ball milling doped powder(3013). It was attributed to the maximum homogeneous distribution of dopants in Ba-Ti initial solution at atomic level via the SAS process.
Mechanically Activated Low-Temperature Synthesis of Ti2SnC
Authors: Li Shi Bo , Zhai Hong Xiang , Bei Guo Ping , Zhou Yang
Published: March 2009

Ti2SnC has been fabricated from Ti, Sn and graphite elemental powders by mechanically
activated low-temperature synthesis (MALS) technique. Superfine powders were obtained after milling
the elemental powders for only 1 h with a charge ratio of 20:1. The mechanically alloyed powders were
then pressureless sintered at different temperatures at Ar atmosphere for 0.5 h. High content of Ti2SnC
was obtained at 950 oC, which is lower than the previously reported temperatures of above 1200 oC by
sintering the conventional mixture powders. The microstructure shows that Ti2SnC grains with plate-like
shape and smooth surface are less than 5 μm in size. The result demonstrates that the MALS is a novel
method for the synthesis of Ti2SnC or other ceramic powders.
Surface Coating of Anhydrite Powders with CaCO3 Nano-Particles Prepared in Ca(OH)2-H2O-CO2 System
Authors: Liu Wei , Gai Guo Sheng , Xie Qiang , Yang Yu Fen
Published: March 2009

Anhydrite powders with nanostructure surface were prepared in Ca(OH)2-H2O-CO2 system.
The effects of preparation parameters such as Ca(OH)2 concentration, revolution speed of mixer, temperature
on surface finish and reaction speed were investigated. SEM was used to observe the changes of the
morphology of anhydrite powders before and after surface coating. The results show that the appropriate
condition is: the concentration of Ca(OH)2 should be 2~3%, the temperature between 20~25°C is better,
the revolution speed should be big enough and so on. In order to gain nanostructure surface, appropriate
technological parameter should be chosen carefully. The SEM photographs show that Anhydrite powders
had fine surface morphology after surface finish that the smooth cleavage planes were coated with nanometer
particles and the sharp edge angles were blunt by the coating of CaCO3 nanometer particles.
Effect of Laser Parameters in the Micromachining of Silicon by Femtosecond Pulse Laser
Authors: Geng N. , Fu Xing , Li H.X. , Ni X.C. , Hu Xiao Tang
Published: March 2009

A 775nm femtosecond laser is applied to single crystal silicon by direct-write processing in air. A series of holes are drilled with 150fs duration pulses, various numbers of laser pulses and laser fluences on silicon wafer. Different laser parameters and material properties influence the size of fabricated holes. The diameter and depth of holes are gradually enlarged with the increase of laser fluence and pulse number. The periodic ripple structure on silicon surface is found and explained at the same time.
A Novel Micro Sliding Rotary Engine
Authors: Wang J.H. , Lu D.J. , Jiang Zhuang De , Chen X.N.
Published: March 2009

In recent years, there is an effort to develop a portable, autonomous micro power generation system to obtain an order of magnitude improvement in energy density over general alkaline or lithium ion batteries. As hydrocarbon fuels have much higher energy to weight ratios than general batteries, researches to realize micro-engines fueled by such hydrocarbon fuels are carried out in some universities or institutes. The first key problem of the researches is how to get a micro-engine structure suitable for MEMS (Micro-Electro Mechanical Systems) fabrication. This micro-engine structure needs characteristics such as planar geometry, self-valving operation and a minimal number of moving parts and so on. In this paper, a micro sliding rotary type combustion engine structure is presented and described. The intrinsic characteristics of the engine housing curve named of “kindred cardioids curve” are described in details. The structural scheme and cycle process of the micro-engine are discussed. Some performance parameters of the micro engine are theoretically calculated with H2-Air mixture and specified geometry parameters. The primitive calculated results indicate that the sliding rotary combustion engine is workable and effective.
Study on Displacement Self-Sensing of Piezoelectric Actuator
Authors: Cui Y.G. , Dong Wei Jie , Gao C.Y. , Zeng Q.Y. , Sun Bao Yuan
Published: March 2009

This paper aims to make piezoelectric ceramic actuator self-sense its own displacement in the absence of independent sensor. It is derived from the basic piezoelectric equation that the free charge on the wafer of piezoelectric ceramic actuator contains displacement information. So a displacement self-sensing method based on integrate circuit is presented. Voltage driving circuit for the piezoelectric ceramic actuator and integrated circuit for gathering free charge are designed. Based on the proposed compound circuits, the actuator can sense its own displacement while actuation. It is convenient to adjust the circuit and easy to acquire sensitive signal by using this method, and the impedance mismatching problem met in bridge method is overcome. The experimental results show that piezoelectric self-sensing actuator can effectively measure its displacement signal under the conditions of different wave form of driving voltage and different driving voltage frequency.
Fabrication of Micro Parts with Micro-WEDM
Authors: Di Shi Chun , Huang R.N. , Chi Guan Xin , Zhao W.S.
Published: March 2009

A new Micro-WEDM machine is developed in this paper. Therefore, experiment can be done on this machine. Especially, the surface characteristics of work-pieces are analyzed in detail. The Micro-WEDM can machine micro slot easily. In addition, all kinds of micro shaped holes, micro gears, complex micro parts and dies are machined to check its processability. A micro gear can be easily fabricated by micro-forming method with the micro gear dies fabricated by micro-WEDM, and get well performance, which indicates that micro parts machined by Micro-WEDM meet the requirements of micro instrument and device.
A Survey on Control of Parallel Manipulator
Authors: He J.F. , Jiang H.Z. , Cong D.C. , Ye Zheng Mao , Han Jun Wei
Published: March 2009

Based on extensive study on literatures of control of parallel manipulators and serial manipulators, control strategies such as computed torque control, PD+ control, PD with feedforward compensation, nonlinear adaptive control are classified into two categories: model-based control and performance-based control. Besides, as advanced control strategies, robust control and passivity-based control for the parallel manipulators are also introduced. Comparative study in view of computation burden and tracking performance are performed. It turned out that the physical structure properties of parallel manipulators’ dynamics are similar with that of serial ones, and this constitutes a common foundation for the two kinds of manipulators to develop together that control design of parallel manipulators can start with ever established control methods of serial manipulators.
Residual Area Max Depth Model for Nanoindentation Hardness Size Effect of Single Crystal Silicon
Authors: Zhou L. , Yao Ying Xue , Pahlovy Shahjada Ahmed
Published: March 2009

In material nanoindentation hardness testing, the hardness will decrease with the indentation depth or peak load increase, i.e. indentation size effect (ISE). There are several models and equations were proposed to describe ISE. But the variables self-inaccurate in these models and equations, it will affect the result trueness. Single crystal silicon was used for nanoindentation experiments, and max depths were obtained from these experiments. Combining Matlab software, residual areas were obtained by atomic force microscopy (AFM). Based on max depth and residual area, a new model—residual area max depth model was proposed for indentation size effect in nanoindentaion hardness. The new model perhaps can understand and describe ISE in indentation hardness better than other models and equations.
A Study of Factors Affecting Surface Quality in Ultra-Precision Raster Milling
Authors: Cheng M.N. , Cheung Chi Fai , Lee Wing Bun , To Sandy
Published: March 2009

Ultra-precision raster milling is an emerging manufacturing technology for the fabrication
of high precision and high quality components with a surface roughness of less than 10 nm and a form
error of less than 0.2 μm without the need for any subsequent post polishing. Surface quality of a
raster milled surface is affected by process factors and material factors, respectively. The process
factors involve cutting conditions, cutting strategies, and relative vibration between the tool and the
workpiece which are related to the cutting geometry and the dynamic characteristics of the cutting
process. The material factors considered are material property and swelling of the work materials.
Due to different cutting mechanics, the process factors affecting the surface quality are more
complicated, as compared with ultra-precision diamond turning, such as swing distance and step
distance. This paper presents an experimental investigation of the distinctive process factors affecting
the surface roughness in ultra-precision multi-axis raster milling. Experimental results indicate that
the influence due to the process factors can be minimized through a proper selection of operational
settings and better control of dynamic characteristics of the machine.
A Novel Architecture for Compiled-Type Software CNC System
Authors: Yao Ying Xue , Yu Shun Zhou
Published: March 2009

PC-based software computer numerical control (CNC) system is the ideal for open CNC
system, but there are some problems about the current open CNC system, such as the limitation of
interpolation cycle, demanding on high-speed and high precision machining and the limitation of
operation system (OS). So advances a novel PC-based architecture for compiled-type software CNC
system, in the architecture, the general Windows is adopted as CNC platform and adopts two huge
memories acting as data buffer to solve real time problem. And then analyzes the structure and basic
principle of compiling system. The hardware has been developed based on this architecture and
applied in the CNC system.
An Accurate Method for Calculating Load Distribution Factor Kβ of Involute Gears
Authors: Feng D.C.
Published: March 2009

A new method is given to determine the load distribution factor Kβ of involute gears.
Compared with the old method, the new one gives up some improper assumptions such as linear load
distribution along gear tooth width. While considering the effects of bearing deformations, gear
manufacture and assembly errors, gear axial force and gear tooth run-in on Kβ, the paper calculates Kβ
according to “Load- Deformation Coordination” of gear tooth. Practical examples show that this
method is more accurate, more effective than old ones.
Interpolation Approximation Design of Pin-Jointed Four-Bar Linkages with Corresponding Angular Displacements of Grounded Links
Authors: Feng D.C.
Published: March 2009

Interpolation approximation is used in the design of Pin-jointed Four-bar Linkages with
corresponding angular displacements of grounded links to realize approximately a given function.
First Four-bar linkage position equations with parameters to be determined are established；then the
paper sets up the relationships between given function and approximation function；finally it chooses
Chebychev interpolation points to determine the approximation function. Angular error analysis is
also conducted. A design example is given for reference in the end.
The Theoretical Study on the Mechanism of BDT in Machined Si Single Crystal
Authors: Wang Ming Hai , Lu Ze Sheng
Published: March 2009

The mechanism of brittle-ductile transition (BDT) in machined Si single crystal is investigated by simulating dislocations emission from crack tip along (111) and (111) slip plane under mixed-mode loading. One kind of compression-shear crack is taken into account and the law of strain-energy-density-factor is applied as fracture criteria. The total number of the emitted dislocations and the number of dislocations in each slip plane at the onset of cleavage are calculated. It is found that the ratio of stress intensity factor kII to kI that the crack tip is subjected has significant effect on the BDT in machined Si single crystal. Then the results are applied to study the action of negative rake angle and edge radius of diamond tool in the ultra-precision turning.
An Internal Variable Approach to Inelastic Deformation Including Structural Superplasticity
Authors: Chang Young Won
Published: March 2009

An internal variable theory has been proposed to account for the essential microstructures
during inelastic deformation. The framework of the theory is built on the basis of well known
dislocation dynamics to provide the concept of an internal strain tensor as the most fundamental
deformation state variable. The plastic and inelastic strain rate tensors are then naturally defined and
also a kinematics relation among them can further be derived from the time rate of change of this
internal strain tensor, which in fact accounts for the evolution of microstructures during inelastic
deformation. To complete the theory, the constitutive relations between the various stress variables
and their conjugate deformation rate variables are then derived based on the dislocation kinetics. The
theory is then further extended to describe the structural superplasticity, taking this slip zone model
with dislocation pile-ups as the major accommodation mechanism for grain boundary sliding. The
experimental results obtained from the various crystalline materials are then presented and compared
with each other in relation to the internal variable theory for inelastic deformation.
Multi-Scale Modeling of Surface Topography in Single-Point Diamond Turning
Authors: Lee Wing Bun , Cheung Chi Fai , To Suet
Published: March 2009

A multi-scale model is proposed to explain the effect of material induced vibration and
the quantitative relation between cutting force and the surface quality from dislocations, grain
orientations, cutting tools, machine tools used in the simulation of the nano-3D surface topology
in single-point diamond turning. The model-based simulation system composes of several model
elements which include a microplasticity model, a dynamic model and an enhanced surface
topography model. The multi-scale model brings together knowledge from various disciplines to
link up physical phenomenon occurring at different length scales to explain successfully the surface
generation in single-point diamond turning of crystalline materials, and offers a new direction of
research in ultra-precision machining.
Mechanics of Carbon Nanotubes: A Continuum Theory Based on Interatomic Potentials
Authors: Jiang Han Qing , Hwang Keh Chih , Huang Young
Published: March 2009

It is commonly believed that continuum mechanics theories may not be applied at the
nanoscale due to the discrete nature of atoms. We developed a nanoscale continuum theory based on
interatomic potentials for nanostructured materials. The interatomic potential is directly incorporated
into the continuum theory through the constitutive models. The nanoscale continuum theory is then
applied to study the mechanical deformation and thermal properties of carbon nanotubes, including
(1) pre-deformation energy; (2) linear elastic modulus; (3) fracture nucleation; (4) defect nucleation;
(5) electrical property change due to mechanical deformation; (6) specific heat; and (7) coefficient of
thermal expansion. The nanoscale continuum theory agrees very well with the experiments and
atomistic simulations without any parameter fitting, and therefore has the potential to be utilized to
complex nanoscale material systems (e.g., nanocomposites) and devices (e.g., nanoelectronics).
Experimental Study on Elastic-Plastic Behavior of a Sandstone under Ground Temperature
Authors: Zhou Qing Chun , Li Hai Bo , Yang Chun He
Published: March 2009

The mechanical properties of rock under high temperature and high geostress are the
basic and important information to assess the safety of underground engineering. Based on the
environmental conditions of the west route of south-to-north water transfer project in western
China, experiments are conducted for a sandstone. The experiments are conducted in stress path of
hydrostate, pure shear, and conventional triaxial compression at the temperature of 25°C, 50°C and
70°C. The change of strength and average moduli of the rock with temperatures are studied. By
cycle loading and unloading tests, elastic and plastic deformation of the rock are decomposed, it is
shown that the plastic deformations of the rock are clearly changed with temperature, while the
elastic deformation of the rock seems to be unaffected by the temperature. Moreover, based on the
associated plastic flow rule, a constitutive law considering temperature is proposed for the
sandstone.
Statistical Analysis on Strength of Rock Based on YAI Concept
Authors: Zhang Chuan Qing , Feng Xia Ting , Zhou Hui
Published: March 2009

In this paper, a new concept, YAI (yielding approach index), is firstly proposed to estimate
the safety differences of rock and rockmass whose stress states are close to yielding. Secondly, in
order to describe the intrinsic heterogeneity of strength of the same rock, the safety parameter ω,
which is the phase complementary parameter of YAI, is supposed to be a stochastic variable in this
paper and conform to the Weibull’s distribution. By analyzing the triaxial test data of five types of
rocks, it can be found that ω as a stochastic variable evidently conforms to the Weibull’s distribution.
Results in this paper give an important and useful reference to the safety analysis for geotechnical
engineering.
Study on the Mechanical Property and the Evolutionary Neural Network Constitutive Model for Limestone under Chemical Corrosive Environments
Authors: Ding Wu Xiu , Feng Xia Ting , Chen Bing Rui
Published: March 2009

In this paper, the experimental study on the mechanical property of limestone under
triaxial compression with different hydrochemical environments is conducted and the non-linear
characteristics of complete stress-strain process of limestone subjected to chemical corrosion, are
analyzed. The behaviors of deformation and strength of limestone eroded by different chemical
solutions are obtained. It is known from the experimental and analytical results that different
chemical environments such as chemical composition, pH value etc can affect the mechanical
property of rock differently. How to establish a multifactor characteristic constitutive model which
can reflect different chemical environments is the key problem to study the coupling corrosion effect
of stress and chemistry of rock. The constitutive model of evolutionary neural network for rock under
chemical corrosive environments is put forward, and the neural network constitutive relationship
under stress-chemistry coupling corrosion is established by applying the theory of evolutionary
computation and neural network. The neural network constitutive model established in this presented
paper mainly takes into account the following three aspects: chemical environments of rock
specimens, content of main mineral compositions that are liable to being eroded by chemical solution,
and mechanical environments. The results are in good agreement with the experimental data.
Deformation Behavior of Shape-Control Plate Using NiTi Shape Memory Alloy Wire
Authors: Tohgo Keiichiro , Tochigi Yuki , Araki Hiroyasu , Shimamura Yoshinobu
Published: March 2009

This study deals with deformation behavior of a shape-control plate which consists of an
aluminum alloy plate and a pre-strained NiTi shape memory alloy (SMA) wire. The shape-control
plate exhibits reciprocating bending deformation by heating and cooling. Deformation behavior of the
plate is examined by electric heating and natural cooling of the SMA wire. Experimental results
exhibit that the bending deformation of the plate is considerably stable over more than two thousand
heating-cooling cycles and can be well controlled by electric current. Furthermore, the deformation
behavior of the plate is analyzed by a simple beam theory for the aluminum alloy plate and Brinson’s
one-dimensional constitutive model for the SMA wire taking account of not only martensitic
transformation but also rhombohedral-phase transformation. Numerical results describe well the
deformation behavior of the shape-control plate observed in the experiments.
A Hydro-Mechanical Coupled Analysis of an Unsaturated River Embankment due to Seepage Flow
Authors: Oka Fusao , Kodaka T. , Kimoto Sayuri , Kato R. , Sunami S.
Published: March 2009

In this paper, a soil-water coupled elasto-plastic finite element analysis is applied to the
problem of seepage flow by incorporating unsaturated seepage characteristics and assuming the pore
air pressure in the unsaturated soil region to be atmospheric pressure. It is shown that the proposed
soil deformation–seepage flow coupled analysis method is applicable to safety investigations of river
embankments and that the existing evaluation criterion for the seepage failure of river embankments
is not always on the safe side.
Parameter Identification of Soil Hyperbolic Constitutive Model by Inverse Analysis Procedure
Authors: Li Shou Ju , Liu Ying Xi , Cao Hai Yun , Cheng Dong
Published: March 2009

A tangent modulus of soil mass which allows for a piece-wise linear approximation of the
hyperbolic response curve is particularly suited for incremental construction simulation. The
parameter identification of nonlinear constitutive model of soil mass is based on an inverse analysis
procedure, which consists of minimizing the objective function representing the difference between
the experimental data and the calculated data of the mechanical model. The artificial neural network
is applied to estimate the model parameters of soil mass. The weights of neural network are trained
by using the Levenberg-Marquardt approximation which has a fast convergent ability. The
parameter identification results illustrate that the proposed neural network has not only higher
computing efficiency but also better identification accuracy. The numerically computational results
with finite element method show that the forecasted displacements at observing points according to
identified model parameters can precisely agree with the observed displacements.
Strength and Interaction of Soil Reinforced with Three-Dimensional Elements
Authors: Zhang M.X. , Zhang S.L. , Peng J.M. , Javadi A.A.
Published: March 2009

For conventional reinforced soil, the reinforcements are put horizontally in the soil. A new
concept of soil reinforced with three-dimensional elements was proposed. In 3D reinforced soil,
besides conventional horizontal reinforcements, some vertical and 3D reinforcements can also be laid
in the soil. The triaxial tests on sand reinforced with 3D reinforcement were carried out. From the
experimental results, the differences of stress-strain relationship and shear strength between
horizontal reinforced sand and 3D reinforced one were analyzed. The experimental results show that
3D reinforcement not only increases its cohesion, the angle of internal friction has been increased
greatly, especially with 3D elements on both sides. Based on experimental results, a retaining
structure reinforced with 3D reinforcements was analyzed by the finite element method. The stress
distribution and interaction between 3D elements and soil were studied. The plastic zone and stability
analysis of the retaining structure reinforced with 3D reinforcements were investigated by finite
element method by shear strength reduction technique.