bluuebunny/crossref_metadata_2025 huggingface dataset:
A Damage Detection Method: CMSE Combined with Niche GA
Authors: Ge Xu , Yan Yun Ju , Chen Huan Guo
Published: March 2009

The paper presents an effective damage detection method of complex composite structures.
It can be carried out through the experimental modal analysis of the damaged structure. The method
using the improved Cross Modal Strain Energy (CMSE) technique and Niche GA has many
advantages compared with other damage detection methods. The CMSE method can use any modes
of the structure and the modes don’t need to be normalized or consistent in scale. The Niche GA
improves the efficiency of the calculation and enhances the capacity of identifying structural damage
localization. The model is the composite material airfoil case. The numerical results show that the
method proposed in this paper is successful for damage detection of complex structures.
Effect of Different Electrode Materials on the Performance of Smart Composite Actuators Based on Dielectric Elastomers
Authors: Khodaparast P. , Ghaffarian S.R. , Khosroshahi M.R.
Published: March 2009

Dielectric elastomers are a class of electro-active polymers (EAPs) which have great
potentials to be used in smart composites. These materials with compliant electrodes are converters of
electrical energy to mechanical energy in order to produce external load and strain with good
efficiency. Electrode materials should typically have good compliancy so that undergo large strain
alongside the film, without producing any additional stress and constraint for the actuator. In the
present study, the effect of 4 different electrode materials (graphite filled silicone oil, silver filled
grease, graphite powder and electrically conductive silicone rubber) on the performance of dielectric
elastomer actuators has been studied. The principle of operation, the method of fabrication and test
method of planar actuators are discussed. We have also studied the effects of different driving
voltages and different prestrain values on the actuator response. Experimental results showed that
electrical conductivity, material compliancy, and compatibility with substrate in the electrode
materials are some of the important parameters affecting the actuator performance.
Study on Processing Parameters of Ceramic Injection Moulding
Authors: Yu Xin Gang , Zuo Yan Bin , Gong Yi , Xie Zhi Peng , Liu Lan Yun , Yang Jin Long , Li Jian Bao , Huang Yong , Wang Lin
Published: March 2009

According to the heat transmission theory, in the aid of computer, the temperature distribution in the cylinder cavity was calculated. The temperature of the mould has much influence on the time for the injection material’s temperature of the cavity center to drop to the injection material softening temperature. The influence of the processing parameters on the density of the injection molding specimens was also investigated. It turns that the injection molding specimens’ density changes little with the increase of injection temperature and pressure, but changes a lot with the increase of holding pressure time.
Synthesis and Characteristics of Infrared-to-Visible Upconversion Nanoparticles through a Microemulsion System
Authors: Wang Ting , Wang Yue Hui , Shi Shi Kao , Li Bo , Zhou Ji
Published: March 2009

Infrared-to-visible upconversion phosphors Y2O3: Yb, Er and Gd2O3:Yb, Er with narrow size
distribution were synthesized by using a stable microemulsion system, which included triton X-100,
n-hexanol, cyclohexane and water. Appearance-controllable nanocrystals were achieved by adjusting the
ratios of assistant surfactant and surfactant. The X-ray diffraction patterns of the samples showed that the
powders were cubic phases of Y2O3 and Gd2O3, respectively. After calcination with different temperature
settings in air atmosphere, the particles were spherical through the observation by scanning electronic
microscopy. Red and green upconversion luminescence was obtained under 980 nm infrared excitation.
Several contributions to the intensity of upconversion emission were also investigated. These
upconversion phosphors may be used as fluorescent labels for the sensitive detection of biomolecule,
immunoassay or DNA assays.
Extrusion Forming of Cordierite Honeycomb with Hexagonal Open Cells
Authors: Yoon Dae Hyun , Shin Dong Woo
Published: March 2009

Cordierite honeycomb with hexagonal shaped open channels was formed by extrusion forming
technique using specially designed mould for the raw oxide mixture of talc, kaolin, alumina and
aluminum hydroxide. The honeycomb showed extremely thin wall thickness of 0.15 mm and low
coefficient of thermal expansion (CTE) for the high number of cells per square inch (cpsi) approaching to
600. The extruded honeycomb was sintered at various conditions and characterized by XRF, TGA-DTA,
XRD, TMA and SEM techniques. The indialite crystalline showing the coefficient of thermal expansion
of 1.9 × 10-6/°C was formed while sintering at 1,450°C for 5 h. The influence of Fe2O3 additive and
heating condition on the CTE of cordierite was analyzed in details. This particular cordierite honeycomb
with high numbers of hexagonal shaped open cells showed a distinct advantage of saving the amount of
precious metal catalyst materials to be coated on the substrate in comparison with the honeycomb with
rectangular cells while improving the degree of catalyst efficiency when applying the substrate of
automotive catalytic converter.
Microwave Sintering of Alumina-Silicon Carbide Nanocomposites
Authors: Ahmad Kaleem , Pan Wei , Si Wen Jie
Published: March 2009

Densification behavior, microstructural developments and mechanical properties of 5 wt% SiC nano particulate toughened Al2O3 composites were prepared by using microwave sintering at different sintering temperatures. Densities of up to 97.5% of the theoretical value were achieved at temperature as low as 1380°C. Improvements in fracture toughness and bending strengths are of the order of 99% theoretical dense conventionally sintered composites. Surface heating was observed at the final stages of densification. No thermal runaway was observed in the nanocomposites due to presence of SiC spheroids.
Preparation of Porous Si3N4 Based Ceramics by Combustion Synthesis
Authors: Li Wen Kui , Xiang Jun Huai , Zhang Bao Lin
Published: March 2009

This paper presents the results of combustion synthesis of porous Si3N4 based ceramics from
silicon powders, with fine α-Si3N4 and BN powders as diluents, under high nitrogen pressure. The effect
of addition of BN on the morphology is investigated. The results revealed that the strength decreased and
the porosity increased with the addition of BN, which is strongly depended on the final morphology of the
products.
(Ca,Sr,Ba)TiO3-Based Dielectrics Sintered in Reducing Atmosphere
Authors: Lu Zhen Ya , Wu Jian Qing , Chen Zhi Wu
Published: March 2009

The anti-reducing sintering of (Ca,Sr,Ba)TiO3-based dielectrics was achieved by the cooperating
effect of Mn2+, Ca2+, Mg2+, Dy3+ and Yb3+. A small quantity of Zr4+ partly substitution for Ti4+ can
improve the temperature dependence of dielectric constant. But ZrO2 will also reduce the solid solubility
of BaTiO3-SrTiO3-CaTiO3 ternary system, and may cause phase separation. The separated ferroelectric
phase increases the capacitance change under DC bias. Non-reducible (Ca,Sr,Ba)(Ti,Zr)O3-based dielectrics
with single orthorhombic phase of perovskite structure was obtained. The dielectric and DC bias
properties are: .C/C (DC bias: 1.5kV/mm) <0.05%, ε =250~300, tgδ < 0.5%.
RB-SiC Ceramics Derived from the Phenol Resin Added with Starch
Authors: Cheng Peng , Qiao Guan Jun , Li Di Chen , Gao Ji Qiang , Wang Hong Jie , Jin Zhi Hao
Published: March 2009

Reaction bonded silicon carbide (RB-SiC) was fabricated by phenol resin, starch, solidified
agent and silicon powder through the following steps: first, carbonizing at high temperature for 7-9h,
infiltrating silicon at 1450-1600oC for 0.5-2h, and then removing excessive silicon at 1700oC for 0.5h.
Scanning electron microscopy and X-ray diffraction were employed to characterize and analyze the
microstructures and phase composition of the preforms and the final RB-SiC products. In addition, the
effect of carbonization temperature, the amount of starch and solidified agent on strength and apparent
porosity of final RB-SiC were also discussed. The results showed that the carbonization process of phenol
resin can be divided into three steps: at temperatures from 400oC to 600oC, the structure of polymer
changes less; at temperatures from 600oC to 1000oC, the fundamental chain of polymer is destroyed, and
inverts to glass-like carbon; at temperatures from 1000oC to 1200oC, with the increasing of carbonization
temperature, the structure of glass-like carbon changes into the structure of disorder graphite. And the
increased micro-pores could be obtained by adding starch.
A Comparison Study on Microstructure and Mechanical Properties of Si3N4 Ceramic Prepared from MACS Powders
Authors: Ren Ke Gang , Chen Ke Xin , Jin Hai Bo , Ning Xiao Shan , Zhou He Ping
Published: March 2009

In present work, ultra-fine powders with alpha phase content higher than 95 wt% and specific
surface area of 15.33 m2/g were prepared by mechanical activated combustion synthesis (MACS) process.
The sinterability of as-fabricated Si3N4 as well as the microstructure and mechanical properties of the
sintered bulk were investigated by comparing with a kind of commercial available Si3N4 powders used as
diluents in MACS process. Employing hot-pressing method, both powders were sintered equally by using
Y2O3 and Al2O3 as sintering aids. Results showed that smaller particle size and higher specific surface
area were obtained by MACS process when compared with the commercial one. Bulk Si3N4 appeared
approximately the same relative density, hardness, strength and fracture toughness, however, proved to be
higher while using MACS powders.
Processing of Zinc-Based MgAl2O4 Composite and Effect of Fly Ash Addition
Authors: Gürü Metin , Korçak M. , Tekeli Süleyman , Güral Ahmet
Published: March 2009

The properties of ceramic-metal (Cermet) composites as tensile strength, hardness and
resistance to corrosion and high temperature are superior than ceramics and metals. Because of the
enhanced characteristics of cermets, they are commonly used in various applications and industries.
The main objective of this study is to produce a cheap, easy produced, strong and high corrosion
resistant composite material. For these purposes, zinc is used for its natural capacity against corrosion,
low density, low melting point and softness. Magnesium aluminates spinel oxide (MgAl2O4) is
chosen because of its high melting point and low density. Fly ash is a waste from coal power plant
having puzzolanic properties. In this study, the effect of various amounts of zinc and fly ash addition
on density and hardness behaviour of zinc-based MgAl2O4 composites was investigated. The
experimental results showed that zinc and fly ash addition improved the hardness behavior of zincbased
MgAl2O4 composite.
Influence of Pressure on the Crystallization in SiO2f/SiO2 Composites
Authors: Xu Chang Ming , Wang Shi Wei , Huang Xiao Xian , Guo Jing Kun
Published: March 2009

The influence of pressure on the crystallization behavior in SiO2f/SiO2 composites hotpressed at 1350°C was studied. The crystalline phase composition analysis on SiO2f/SiO2 composites revealed that the formation of cristobalite was promoted when the hot-pressing pressure ≤ 12 MPa, however suppressed with higher pressure applied. It can be ascribed to the nucleation mechanism change from surface nucleation to bulk nucleation. Analysis on relative density as well as fracture microstructure of SiO2f/SiO2 composites confirmed the conclusion.
Effect of Catalyst on the Preparation of Silicon Carbide Whiskers from Silica and Carbon
Authors: Xie Mu Wen , Qi Long Hao , Xu Qiang
Published: March 2009

Silicon carbide whiskers (SiCw) as a kind of high strength fibrous material are widely used in
the reinforcement of metal, ceramic and polymer. In this paper preparation of Silicon carbide whiskers by
carbon thermal reduction reaction from the mixture of Silica and carbon was investigated with an
emphasis on the study of the effect of catalyst. Fe, Co, Ni and their compounds were used as catalyst in
this study. Since vapor–liquid–solid (VLS) mechanism was found to be responsible for the growth of
whiskers, the formation of catalyst and its subsequent evolution on whisker nucleation, growth and
appearance was a subject of extensive research. The catalyst that has the best effect among iron, nickel,
cobalt and their compounds was made certain by comparing the products.
Fabrication and Properties of SrBi2(Ta1-xNbx)2O9 Ferroelectric Ceramics
Authors: Wang Wen , Yu Ke , Ke Hua , Niu Hai Jun , Jia De Chang , Zhou Yu
Published: March 2009

SrBi2(Ta1-xNbx)2O9(SBTN) ferroelectric ceramics with typical bismuth layered perovskite
structure were synthesized with a reactive hot-press sintering process at 1000°C for 2h. The as-sintered
SBTN (x=0.2, 0.4, 0.6, 0.8) materials had a maximum relative density of 95.97%. Bi-layered perovskite
structure was obtained. The grain sizes increased with increasing Nb content. In 1MHz frequency,
remanent polarization (Pr) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 10.0, 3.0, 1.7 and 1.0, while coercive field
(Ec) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 50, 32, 33 and 33kV/cm, respectively.
Effect of Micro-Pores after Sintering on Wear Behavior of Zirconium Silicate Composite Microbeads
Authors: Xi Xiao Qing , Yang Jin Long , Zhang Xin Yue , Ouyang Xiao
Published: March 2009

The composite zirconium silicate microbeads with different pretreating process were
developed in this paper. The wear loss of these microbeads was compared by testing of agitation mill.
These microstructures with different micro-pores were compared by scanning electron microscopy. The
pore size was found have obvious influences on the mechanism of the wear. Some solutions were
proposed to overcome the micro-pores in the zirconium silicate composite microbeads.
High Speed Lapping of SiC Ceramic Material with Fixed Abrasive
Authors: Yang Xin Hong , Zhang Yu Min , Han Jie Cai
Published: March 2009

An experimental investigation is carried out to machine SiC ceramic material through method
of high speed plane lapping with fixed abrasive. The results show that the material removal mechanism
and the surface roughness are chiefly related to the granularity of abrasive and the lapping pressure for the
brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic material in ductile mode
with a high efficiency and a low cost using W3.5 grit under a lapping pressure of 0.1MPa and then a
smooth surface with surface roughness of Ra 2.4nm can be achieved.
Synthesis and Properties of Silica Aerogel by Using Acid Silica Sol and TEOS as Silicon Sources
Authors: He Fang , Zhao Hai Lei , Qu Xian Hui , Qiu Wei Hua , Wu Wei Jiang
Published: March 2009

Silica aerogels were synthesized from hybrid silicon sources of TEOS and acid silica sol by
two-step sol-gel method and supercritical drying. Different chemical compositions of the starting solution
were altered in order to make an insight into the relationship between process parameters and the
microstructural characteristics of resulting silica aerogels. The results indicate that a certain amount of
acid silica sol may promote the gelation process while excessive nano-scaled silica particles easily result
in dense structure and low specific surface area. The gelation time increases with the increasing water
amount. Excessive water will lead to weak network structure of silica gels and thus larger shrinkage and
lower porosity of the resulting silica aerogels.
In Vitro Degradation of β-TCP/PLLA Scaffolds with Different Proportions of β-TCP
Authors: Luo Lin , Yin Guang Fu , Zhang Yun , Yao Ya Dong , Yang Wei Zhong , Wang Yue Hua
Published: March 2009

Porous biodegradable scaffolds are widely used in bone tissue engineering to provide
temporary templates for cellular attachment and matrix synthesis. Ideally, the degradation rate in vivo
may be similar or slightly less than that of tissue formation, allowing for the maintenance of the scaffold
structure and the mechanical support during early stages of tissue formation. Eventually, the 3-D spaces
occupied by the porous scaffolds will be replaced by newly formed tissue. In this work, β-tricalcium
phosphate/Poly-L lactide (β-TCP/PLLA) scaffolds with different proportions of β-TCP to PLLA were
investigated. The effects of β-TCP proportions on degradation rate and mechanical strengths of the
scaffolds were evaluated in simulated body fluid (SBF) at 37°C up to 42 days. Results show that: different
proportions of β-TCP to PLLA have significant influence on degradation behaviors of the scaffolds, and
mechanical strengths of the scaffolds with weight proportion of β-TCP to PLLA being 2 to 1 are much
higher than those of the others during the degradation period. And in this period, the scaffolds biodegrade
slowly, and Hydroxyl Carbonate Apatite (HCA) forms in the surface of the material.
Preparation of Unsintering Calcium Phosphate Macroporous Materials with Hydroxyapatite Nanowhisker In Situ Growth
Authors: Xiao Zhang Ying , Cai Shu , Yu Xian Zhu
Published: March 2009

Unsintering macroporous calcium phosphate scaffolds with macropore sizes of 200∼400μm and hydroxyapatite nanofiber of in-situ growth were prepared by coating porous polyurethane templates with α-tricalcium phosphate bone cement (CPC) slurry, and their subsequent hydrolysis to calcium deficient hydroxyapatite (HAp) during the self-setting processes are presented. The effects of Sr2+ (SrNO3) on the nucleation, growth of the hydroxyapatite nanofiber and phase constitution were studied. The results show that the main component of the coating is HA after hydrolysis for 72h and the Sr2+ added could depress the growth of block or sheet HA crystal and promote the nanowhisker growth. This new processing technique can be used to improve the bioactivity of porous polymer template while maintaining its macroporous structure.
Hydrothermal Preparation of Bismuth Titanate Nanopowders
Authors: Miao Hong Yan , Dong Min , Tan Guo Qiang , Pu Yong Ping , Sun Zheng Qiu
Published: March 2009

Bismuth titanate nanopowders were prepared by the hydrothermal method from Bi(NO3)3·5H2O, TiCl4 and KOH aqueous solution. The influences of reaction temperature and KOH concentration on the crystalline phase, morphology, and grain size of the prepared Bi4Ti3O12 powders were investigated. The results showed that well-crystallized, dispersive Bi4Ti3O12 nanopowders could be prepared by the hydrothermal treatment at 220–260°C for 6 h, in the case of [Ti]= 0.1 M, Bi:Ti = 4:3 and [KOH]=1.0–2.0 M. The prepared Bi4Ti3O12 powders of the orthorhombic structure were observed to be rectangle slice-shaped, and the grain sizes were about 30 nm in width and above100 nm in length. It was also confirmed that the desired concentration of KOH decreased with increasing of the treatment temperature.
Exploring the Osteoinductivity of Calcium Phosphate Ceramics/PLA or Collagen Composites
Authors: Yao Jin Feng , Bao C.Y. , Sun R. , Zhang Y.Z. , Sun L.Y. , Ou Guo Min , Xiong C.D.
Published: March 2009

The purpose of this study is to explore the osteoinductivity of the composite materials (calcium
phosphate ceramics/PLA or collagen composites) with similar physical character of osteoinductive
calcium phosphate ceramics and the influence of the chemical composition of the composite materials on
osteoinductivity, and also to provide an experimental evidence for optimizing the design of the composite
materials. Two kinds of composite materials were prepared. One (BCP/PLA) is fabricated with different
ratio of BCP (biphasic calcium phosphate) ceramics powder and PDLLA powder through the particulateleaching
technique. The other (BCP/collagen) is that BCP ceramics sintered at 1250oC and modified with
collagen. The porous materials cylinders with Φ 5×8 mm were prepared. SEM was used to observe the
microstructure and physical morphology of the composite materials. The two groups of composite
materials cylinders were implanted in the dorsal muscles of four dogs. Six samples of each group were
implanted in each dog respectively. The specimens were harvested at 2, 4, 12 and 24 weeks post operation,
and thin decalcified sections were prepared for light microscopy (LM) analysis to evaluate their
osteoinductivity and compare the capability of osteoinduction. The fibro-tissue and bone-like tissue were
observed in the two composites, but no obvious bone formation was found in the tested periods. The
results indicated that the composite materials could modify the mechanical property of ceramics.
However, if the composite materials were biodegraded soon, new bone could not form into the scaffold,
and the calcium phosphate should be the major component of osteoinductive materials.
Microstructure and In Vitro Bioactivities of HA/Ti Composites Prepared by Hot Isostatic Pressing
Authors: Ke Hua , Zhou Yu , Jia De Chang , Ning Cong Qin
Published: March 2009

Hydroxyapatite (HA)/titanium (Ti) composites were successfully fabricated by hot isostatic pressing at 850°C. The microstructure of 7T2HB (70Ti+20HA+10Bioglass, Vol. %) composites were systematically investigated. The main constituents of the composites are hydroxyapatite and titanium. A simulated body fluid (SBF) with the same ion concentrations as those of human plasma and pH value of 7.4 is selected to evaluate the in vitro biological properties of the composites. After 2-week immersion in SBF, the bioactive apatite formed a very dense film on the surface of the composites. The dissolution of CaO and Ca-P compounds in SBF improves the growth of apatite on the surface of the composites.
Micro-Tribological Behavior of Boron Carbide Self-Mated Pairs
Authors: Wu Fang , Xu Sheng Ming , Chen Song Zhe , Li Lin Yan , Xu Gang , Wang Ling Sen
Published: March 2009

Tribological behavior of B4C-SiC self-mated pairs was studied, and pre-oxidation treatment
was adopted to improve the tribological properties of B4C-SiC. At the same SiC content, self-friction
coefficient of B4C-SiC decreases with the increase of sliding distance, normal load, and sliding velocity;
while the increasing of SiC content leads to increase of both self-friction coefficient and ware rate, which
was determined to be within the range of 0.8×10-6~5.8×10-6 mm3·N-1·m-1. Pre-oxidation treatment of the
B4C-SiC resulted in the formation of B2O3/H3BO3 lubricant layers, which effectively reduced the
self-friction coefficient.
Frictional Performance of Brake Pads against Al Metal Matrix Composites with Different Sizes of SiC Particles
Authors: Zhang Shao Yang , Wang Fu Ping
Published: March 2009

Two drums suitable for a Chase Machine were made of Al metal matrix composites containing
25vol.% SiCp with 3.5 μm and 34 μm in nominal diameter respectively. The same brake pads were
measured on the Chase Machine installing each individual drum. It has been found that the brake pads had
better frictional performance and wear resistance against the drum with the large-size SiCp than against
the drum with the small-size ones. Friction fade took place at elevated temperatures - above 316 oC, but
the original level of friction coefficient could be regained rapidly upon cooling with regard to the latter.
The minor level of friction coefficient was attributable to soft Al crystal structure characteristics and thick
tribofilms during the testing stages.
Effects of Pre-Oxide Layer Thickness on Thermal Cyclic Behavior of Thermal Barrier Coatings
Authors: Zhang Dong Bo , Gong Sheng Kai , Xu Hui Bin
Published: March 2009

Conventional two-layered structure thermal barrier coatings (TBCs) with different pre-oxide
layer thicknesses were produced by EB-PVD onto Ni-based superalloy. The pre-oxide layer with different
thicknesses was formed after vacuum heat treatment for 2 hours and before ceramic deposition by heating
the bond coat to 1323K in air for different times. It has been found that with pre-oxide layer thickness
increasing from 1μm to 3.1μm, the growth rate of thermally grown oxide (TGO) increased during thermal
cycling test and the thermal cyclic lifetime of TBCs decreased from 730hs to 400hs Two failure modes
were observed for TBCs with different pre-oxide layer thicknesses and different TGO layer growth rates.
Adsorption of Human Serum Proteins on Carbonaceous Materials
Authors: Li B.G. , Kang Yun Qing , Yin Guang Fu , Zheng Chang Qiong
Published: March 2009

In this paper, the adsorption of human serum albumin (HSA), human serum fibrinogen (HFG) and human serum immune globulin (IG) on surfaces of diamond like carbon film (DLC), diamond film (DF) and graphite has been studied. The adsorption isotherms of single component protein solution and the competitive adsorption of binary system have been investigated by radioisotope 125 I labeling method. Results showed that (1) the adsorptive amounts of HSA on DLC is more than that of HFG, but the adsorptive amounts of HFG on DF and graphite are apparently more than those HSA; (2) the relative competitive adsorption ability of three proteins on DF and graphite surfaces is HFG > IG > HSA, but that on DLC is HFG ≈ HAS > IG, comparison with HSA, there is no apparent competitive adsorption superiority on DLC for HFG. These results indicated that there is no apparent distinction for the adsorption of three human serum proteins on DLC, but the adsorption of HFG on DF and graphite takes precedence in varying degrees. It probably makes rational explanation for the result of blood-compatibility tests in vitro that DLC is good, but DF and graphite are worse.
Fabrication of Ba-Ti-B-Si-O Glass-Ceramics for LTCC
Authors: Cui Xue Min , Zhou Ji , Li Bo , Shen Jian Hong , Wang Yue Hui
Published: March 2009

This paper studied the dielectric performances and microstructure of the Ba-Ti-B-Si-O glass-ceramics fabricated with different methods. The experimental results showed that the pre-calcined method was an effective way to decrease the sintering temperature in glass-ceramic fabricating process, and the dielectric properties of the LTCC materials were εr ≈10, tanδ ≤ 2×10-3 (@1MHz). This study provided a composite method to fabricate LTCC for different applications that was composed of pre-calcined powders and molten powders with different ratios; Moreover, the dielectric constant and sintering performance of composite LTCC were adjustable by changing the ratio of pre-calcined powders and molten powders.
Sintering AlN Ceramics Below 1500°C with MgO-CaO-Al2O3-SiO2 Glass Addition
Authors: Yang Cheng Fu , Cheng Chien Min , Chung Ho Hua , Chan Chao Chin
Published: March 2009

5~15 wt% MgO-CaO-Al2O3-SiO2 (MCAS, fabricated by sol-gel method) glass is used as
the sintering aid of AlN ceramics. The sintering is proceeded from 1350oC~1550oC, scanning electron
microscope is used to observe the sintered morphologies and X-ray diffraction pattern are used to
confirm the crystal structures. From the SEM observations, as 10wt% and 15wt% MCAS is added,
AlN ceramics can be densified at 1500oC and 1450oC, which are much lower than the before studies
were. From the X-ray diffraction patterns, the crystal phases of MCAS-AlN ceramics are AlN, Al2O3,
and cordierite phases. In this study, the dielectric characteristics of MCAS-AlN ceramics are also
developed as a function of MCAS content and sintering temperature.
Synthesis of Bi4-xYbxTi3O12 Nanopowders by a Modified Sol-Gel Process
Authors: Chen Xian Qun , Sun Qiu , Liu Hong Cheng
Published: March 2009

Rare earth Yb-doped bismuth titanate Bi4-xYbxTi3O12 (BYT) nanocrystalline powders were obtained by a modified sol-gel method. TG-DTA, FI-IR and XRD were used to determine the lowest heat treatment temperature. Phase changes in the formation of BYT crystalline powders were discussed by XRD. The effect of Yb3+ cation substitution for Bi3+ cation on the microstructure of BYT was also developed with XRD. The grain size of BYT nanopowders is about 40 nm determined by TEM.
Synthesis of Ce0.8Gd0.05Y0.15O1.9 Nanopowders
Authors: Guan Xiang Feng , Liu Zhi Hui , Zhou He Ping
Published: March 2009

Nanosized Ce0.8Gd0.05Y0.15O1.9 powders were synthesized using glycine nitrate process for use as the electrolyte of intermediate temperature solid oxide fuel cells. The powders were characterized by simultaneous thermogravimetry analysis (TGA) and differential thermal analysis (DTA), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD pattern indicated that the powders exhibited a single phase with cubic fluorite structure. The TEM studies showed that the calcined powders exhibited an almost spherical morphology and the mean size of the particles was 30nm, which is in agreement with the calculated result of XRD.
Preparation and Characterization of CdSe Nanoparticles Prepared by Using Ultrasonic Irradiation
Authors: Sung Myoung Seok , Lee Yoon Bok , Kim Young Seok , Rhyim Young Mok , Kim Jin Chun , Kim In Bae , Kim Yang Do
Published: March 2009

CdSe nanoparticles with average particles size of ~ 3.4 nm were successfully prepared by the sonochemical reduction of a mixed solution of CdCl2, Na2SeSO3 and CH2CH2OH)2NH at room temperature. CdSe nanoparticles characterized by TEM, XPS and XRD analysis revealed the formation of high purity cubic phase CdSe nanoparticles with lattice constant of a=6.415Å. CdSe nanoparticles showed relatively large range of particle size distribution from 20 to 50 nm as the sonication time increased. UV-Vis absorption spectra showed a red-shift in the wavelength region of 545-590 nm as increasing sonication time due to the gradual growth of CdSe nanoparticles in the solution. This paper will mainly present the effects of ultrasonic irradiation on the formation and properties of CdSe nanoparticles.
Synthesis of Hollow Sphere CdSe from CdCl2 Aqueous Solution Containing Ethylenediamine
Authors: Choi Moon Hee , Lee Yoon Bok , Kim In Bae , Kim Young Seok , Rhyim Young Mok , Kim Jin Chun , Kim Yang Do
Published: March 2009

Cadmium selenide (CdSe) of hollow sphere with 30-50nm in diameter have been prepared form
the mixed solution of cadmium chloride (CdCl2), sodium selenosulfate(Na2SeSO3) and ethylenediamine
(H2NCH2CH2NH2) at room temperature. The hollow sphere of CdSe was characterized by transmission
electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray
diffraction (XRD). The molar ratio of EDA to Cd2+ ions in this system was important factor on controlled
synthesis in the self-encapsulated morphology. Based on the observation on morphological difference
with molar ratio of EDA to Cd2+ ion, the possible mechanism for the formation of CdSe hollow sphere
was discussed.
Preparation of Nanoscale High-Purity α-Alumina Powders
Authors: Wu Xiu Lan , Ren Qiang , He Xuan Meng
Published: March 2009

High-purity nanoscale α-alumina powders with high specific surface area were prepared from
boehmite powders synthesized by the method of aluminium isopropoxide hydrolysis. The physiochemical
transformation of boehmite powders under heat-treatment was investigated. The results showed that the
reaction progress of boehmite under heat-treatment is as follows: AlO(OH) → Al2O3 (amorphous) →
γ-Al2O3 → δ-Al2O3 → α-Al2O3. The phase transformation from δ-Al2O3 to α-Al2O3 begins at 1050oC, and
the α-Al2O3 grains growth accelerates as temperature increases. High-purity α-Al2O3 nanometer powders
with higher specific surface area can be obtained after incineration at 1100oC for 4 h.
Photoluminescence and Structural Properties of Si Nanoparticles Embedded in SiO2 Matrix by Reactive RF Magnetron Sputtering
Authors: Ma K. , Feng Jia You
Published: March 2009

In the present work, we investigate the photoluminescence (PL) and structural properties of Si nanoparticles embedded in SiO2 matrix. Si-rich silicon oxide (SRSO) films with Si concentration of 39% were synthesized by reactive RF magnetron sputtering. Annealing was performed at temperatures between 600°C and 1100°C in N2 ambient for 2h to precipitate Si nanoparticles from oxide matrix. Near infrared photoluminescence around 750nm can be clearly observed even in the as-deposited films, which indicates the existence of Si nanoparticles in films. The structural properties were analyzed by infrared absorption and Raman spectra. It is found that the structural properties strongly affect the PL properties of Si nanoparticles embedded in SiO2 matrix.
Synthesis of WC Nanosized Powder by the Plasma Arc Discharge Process
Authors: Lee Seoung Soo , Joo Dong Won , Jung Yeon Gil , Choi Chul Jin
Published: March 2009

WC nanosized powders are synthesized by the plasma arc discharge process and annealing under an inert (Ar) atmosphere. The high temperature used during discharging at local region causes the work-piece and electrode to melt and evaporate. The melted tungsten on the arc discharge electrode and carbon arising from decomposition CH4 gas forms WC1-x nanosized powders. The WC1-x phase is encapsulated in a amorphous carbon shell. The WC1-x nanosized particles are annealed at 1200~1400°C under an Ar atmosphere. The WC1-x nanosized powder is transformed to the W2C phase, and then it becomes WC above at 1400°C.
Surface Nano-Particle Coating of Fly Ash
Authors: Yang Yu Fen , Gai Guo Sheng , Hao Xiang Yang , Chen Q.R.
Published: March 2009

The purpose of the work is to investigate the problems associated with utilization of purified fly
ash (PFA) as filler in polymer. The goal is to expand the application field of fly ash. The wet-collected fly
ash used in this study was sampled from Huaneng Dezhou Power Plant. Preparation of PFA and
composite fly ash (CFA) with nano-structured surface was described in detail. Experimental results show
that CFA with rough surface and high whiteness-value had successfully been prepared in
Ca(OH)2-H2O-CO2 system. The specific surface area of CFA was thrice or above higher than that of PFA
with 2.86 m2·g-1. The whiteness-value of CFA was increased to the range from 63.67 to 73.13 which is
more double than that of PFA with 33.54. Filling tests show that the mechanical properties of
CFA/PE(polyethylene) composites are superior to these of PFA/PE composites at the same filling ratio of
30/100. This means that change of CFA surface morphology increases contacting opportunities between
CFA and polymer matrix and improve the matching state between them when CFA is blended with PE.
The results show that CFA as filler appears to have good application, and yet, little serious research has
been conducted in the field.
Microstructure and Mechanical Properties of Silica Xerogels Doped with SiC Whisker and Short Carbon Fiber
Authors: Yang Li Li , Zhao Jiu Peng , Li Yao
Published: March 2009

Silica xerogels were prepared by sol-gel process and non-supercritical drying. Two kinds of
reinforcements, SiC whisker and short carbon fiber (CF), were chosen to control the shrinkage during
drying process and improve the mechanical properties of xerogels. Microstructure and mechanical
properties of samples were examined. It was found that the addition of SiC whisker could greatly improve
the elastic modulus of silica xerogels, while short CF could prominently decrease the volume shrinkage
ratio but could not improve the elastic modulus. Analysis showed that the difference between the two
reinforcement mechanisms was caused by the interface and the size of the doped fiber and whisker.
Growth of Oxide Nanorod, Nanotube and Nanocable Arrays through Template-Based Sol Electrophoretic Deposition
Authors: Shang H.M. , Wang Ying , Cao Guo Zhong
Published: March 2009

This paper introduces a process for the growth of oxide nanorod, nanotube, and nanocable arrays that combines sol preparation and template-based electrophoretic deposition. Examples are shown that the sol electrophoretic deposition is an effective method for the formation of polycrystalline and single crystal oxide nanorod arrays, nanotube arrays and conformal coating of thin films of oxides on metal nanorods to produce metal-oxide core-shell nanocable arrays.
Structural and Optical Properties of Lead Titanate Nanowires Synthesized by Hydrothermal Method
Authors: Hu Yong Ming , Gu Hao Shuang , You Jing , Zheng Kai Hong , Wang John
Published: March 2009

Lead titanate (PbTiO3) nanowires have been synthesized by hydrothermal method at 200°C for 48h using lead acetic and tetrabutyl titanate as the starting materials and NaOH served as a mineralizer. The phase composition and microstructure of PbTiO3 nanowires were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). The results showed that the obtained nanowires are of single crystalline, tetragonal perovskite structure with diameters of ac. 12 nm and lengths ranging from 500 nm up to 5 μm. The PbTiO3 nanowires have good optical transmissivity. Photoluminescence (PL) study at room temperature for wavelength between 400 and 700 nm reveals a strong light emission band peaking at ac. 471.4 nm (2.63 eV).
Transparent and Compact Zinc Oxide Thin Films via Two-Step Electrodeposition from Aqueous Solution
Authors: Peng Fang , Li Xiao Min , Gao Xiang Dong
Published: March 2009

Zinc oxide films have been deposited on ITO/glass substrate by a two-step electrodeposition method from zinc nitrate aqueous solution. The two-step electrodeposition process included a potentiostatic pre-deposition and a galvanostatic deposition. Obtained ZnO film possesses high c-axis preferential orientation, smooth and compact morphology, high transmittance in the visible band, and optical band gap of 3.43eV. Compared with the film prepared by direct galvanostatic deposition, the crystalline quality and optical properties of ZnO films were significantly improved.
Preparation and Characterization of CdSe/SiO2 Nanocomposites by Sol Gel Method and In Situ Growth
Authors: Peng Yan Xiang , Wang Min Qiang
Published: March 2009

Transparent bulk CdSe/SiO2 nanocomposites, containing semiconductor CdSe nanocrystals
well dispersed in silica glass matrix, were obtained by using sol-gel method and in-situ growth technique.
The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy
(TEM), UV-VIS absorption spectra and X-ray Photoelectron Spectroscopy (XPS). X-ray diffraction and
transmission electron microscope measurements confirmed a cubic crystallographic structure of the
nanoparticles, with mean diameter smaller than 10 nm. UV-VIS absorption spectra displayed a marked
blue shift of the absorption band edge that was attributed to quantum confinement effects. XPS together
with XRD proved that silica matrix plays an important role in enhancing the NCs’ stability.
Evaluation of a Shoe Cushioning System Using Shock Absorber by Biomechanics
Authors: Young Moon Byung
Published: March 2009

This study developed and evaluated a shoe cushioning system to reduce impact force
exerted during running. Load-displacement curves for the shoe cushioning system were obtained
from an instrumented testing machine and the results were compared with various pockets with air,
water or nano-particles. The ground reaction force, force and contact pressure between the shoe and
foot were collected from five young male participants, who are trained and untrained person. This
study used the three cushioning systems such as ordinary shoe, with pocket containing 5 g
nano-particles, with pocket containing 7 g nano-particles. For the trained participant, there was no
significant difference in the cushioning performance among Shoes at a low running speed. But at the
normal speed, shoes with cushion system were better in the cushioning performance. These results
showed that shoes constructed with a shock cushioning system using nano-particles have a better
performance for shock absorption. The significant difference was observed at a high running speed
according to the composition ratio of water and nano-particles inside the pocket of shoe.
Pressure Sensitivity of SiC/Cu Composites Prepared by SPS
Authors: Zhang Rui , Wang Hai Long , Xin Ling , Xu Hong Liang
Published: March 2009

SiC/Cu composites were prepared by spark plasma sintering under different uniaxial pressure.
X-ray diffraction (XRD), SEM techniques were used to characterize the sintered samples. It was found
that higher pressure led to the transformation of Cu into Cu2O. The microhardness of the composites was
improved by SiC reinforcements. The optimised pressure during the spark plasma sintering was about 50
MPa with the maximum hardness of 1.36 GPa.
Sintering Kinetic of Fine α-Alumina Powder with ZrO2 Impurity
Authors: Lin Chung Chieh , Wei Wen Cheng J.
Published: March 2009

Sintering kinetics of the α-Al2O3 powders with average particle size 0.1 μm and ca.1% ZrO2
impurity was investigated. Several two-step sintering methods were tried, and the results were compared
with the conventional (one-step) process. The temperature (<1600oC), holding time (up to 20 h), heating
rate (2 oC /min to 90 oC/min), initial grain size, and porosity were controlled. The optimal results of
two-step sintering, a smaller grain size (0.57 μm) and a good density (>98% TD) were achieved by
heating to 1450oC, then holding at 1350oC for 20 h. The sintering mechanism was determined, belonging
to lattice diffusion in the temperature region of 1400 to 1600oC. The activation energy was 688 kJ/mol,
which was interpreted as a volume diffusion of Al3+ ions in polycrystalline matrix.
Fabrication of Highly Microstructure Controlled Ceramics by Novel Colloidal Processing
Authors: Sakka Yoshio , Uchikoshi Tetsuo , Suzuki Tohru
Published: March 2009

Highly structure controlled ceramics were required for improving their properties. Here, we demonstrate such ceramics fabricated by novel colloidal processing; (i) dense nano-sized zirconia without pressure sintering, (ii) porous ceramics with controlled pore size by hetero-coagulated suspension of ceramics and polymer, and (iii) textured ceramics with feeble magnetic susceptibility by electrophoretic deposition in a high magnetic field.
Evaluating Mechanical Properties of Ceramics by Relative Methods
Authors: Bao Yi Wang , Bu Xiao Xue , Zhou Yan Chun , Liu Li Zhong
Published: March 2009

A relative method, defined as indirect approach to evaluate the material properties via the relationship between unknown properties and a known property, is proposed to estimate some properties that could not be measured by the traditional methods for ceramics. Experiments and theoretic analysis based on the relative method were carried out in this study to estimate the properties in following aspects: determining the temperature dependence of elastic modulus of some machineable ceramics by comparing the deflections; obtaining the modulus and strength of ceramic coatings supported by substrates, from the variation in properties of the rectangular beam samples before and after coating; estimating the residual stresses in tempered glass by comparing the change in the surface strength after strengthening.
Oxidation Behavior and Mechanical Property of Si3N4 Ceramics with Rare Earth Oxide Addition
Authors: Tong Xu Guang , Li Jian Bao , Lin Hong , Yang Xiao Zhan , Yang Jun
Published: March 2009

The effects of rare earth oxides (Lu2O3 and La2O3) on the property, microstructure and oxidation behavior of hot-pressing sintered Si3N4 ceramics were investigated. The silicon nitride ceramics with Lu2O3 and La2O3 as addition have been fabricated by hot-pressed at 1800°C for 1h under a pressure of 25MPa. Oxidation test was carried out at 1400°C in air for 100 hours. Mechanical properties, SEM and XRD were measured before and after oxidation. The results showed that Si3N4 ceramics doped Lu2O3 had good microstructure and mechanical properties than those doped La2O3. Oxidation test showed a parabolic weight gain with oxidation time at 1400°C in air and the oxidation products of the ceramics were SiO2, Re2Si2O7 and Re2SiO5 confirmed by XRD and EDS. The rate-controlling step was the diffusion of ion. The samples doped Lu2O3 showed superior oxidation resistance to those doped La2O3.
Parallel Simulation of Ceramic Grain Growth on the Platform of MPI
Authors: Ji Guo Li , Yang Y.P. , Lin Y. , Xiong Zhao Xian
Published: March 2009

A computation method for parallel simulations of ceramic grain growth at an atomic scale in a
PC cluster is proposed, by combining the Message Passing Interface (MPI) with the serial simulation of
grain growth. A parallel platform is constructed for the simulation of grain growth with program modules
of grain assignments, grain growth, data exchanges and boundary settlements, which are coded with
Microsoft Visual C++ 6.0 and MPICH. Quantitative results show that the computing speed of parallel
simulations with this platform is obviously increased compared with that of serial simulations. Such a
computing mode of grain growth is in good agreement with practical situations of ceramic grain growth.
Bending Behavior of Functionally Graded Piezoelectric Laminated Actuators under Electric Fields
Authors: Shindo Yasuhide , Narita Fumio
Published: March 2009

We present numerical and experimental results on the nonlinear bending behavior due to
domain wall motion in functionally graded piezoelectric actuator under alternating current (ac)
electric fields. A nonlinear finite element method is employed to analyze the dynamic response of
functionally graded piezoelectric actuator. A phenomenological model of domain wall motion is used
in computation, and the effects of ac electric field amplitude and frequency, number of layers, and
property gradation on the deflection of the cantilever actuators are examined. Experimental results,
which verify the model, are presented using a functionally graded bimorph. The numerical results
agree very well with the experimental values.
Preparation of Copper Particles Coated with Amorphous Titania
Authors: Du Shi Guo , Yan Jun , Cui Hai Ping , Liu Xian Jie
Published: March 2009

Amorphous titania coatings on copper particles were prepared by using tetrabutyl titanate to
improve the anticorrosion property. The coated particles were characterized by SEM, EPMA and XRD.
Experimental results showed that the resistance to oxidation of the coated copper particles depended on
the stability and content of the sol. The proper pH value for the sol was about 4, and the ratio of tetrabutyl
titanate and water was 1 to 2. The transmissivity of the etching solution of coated copper particles in 5%
of H2SO4 was more than 80%, showing that the TiO2 coatings on copper particles exhibit an excellent
corrosion resistance.
Dielectric Properties of Ba(Mg0.2/3Zn0.8/3Nb2/3)O3 and Ba1-xSrx(Mg0.2/3Zn0.8/3Nb2/3)O3 Microwave Ceramics
Authors: Cheng S.S. , Luo J. , Xiong Zhao Xian
Published: March 2009

Microwave ceramics of Ba(Mg0.2/3Zn0.8/3Nb2/3)O3 and Ba1-xSrx(Mg0.2/3Zn0.8/3Nb2/3)O3 were synthesized with conventional solid-state reaction method. Dielectric properties of the samples were studied as functions of compositions and sintering temperatures. Experimental results show that a higher Q×f value is reached by substituting Zn ions with Mg ions and a near-zero temperature coefficient of resonant frequency is obtained by replacing Ba ions with Sr ions.
Organic-Inorganic Nanocomposite Electrodes for Dielectric Elastomer Actuator
Authors: Kim Cheol Ho , Jung Hae Do , Lee Jang Oo , Jo Nam Ju
Published: March 2009

This study dealt with the Maxwell stress effect of waterborne polyurethane (WPU)/ conductive filler nanocomposite, which was a promising candidate for a material to be used in dielectric elastomer actuator electrode. Conductive nanocomposites were produced by using three types of conductive filler such as carbon black (CB), vapor grown carbon fiber (VGCF), and silver powder (Ag). Among them, conductive nanocomposite containing VGCF exhibited the lowest threshold concentration. And the blend of CB and VGCF (CB/VGCF) filler had a synergistic effect to electrical conductivity. Actuation test showed that CB/VGCF nanocomposite electrode had the largest displacement. Then it could be stated that the improvement of the displacement in CB/VGCF nanocomposite electrode was originated from the increase in relative dielectric constant. In addition, a unique feature of the hysteresis in the bending deformation was described. The feature is that the prior application of an electric field significantly improves the bending speed in the successive application.