bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Mechanical Mixing and Powder to Liquid Ratio on the Strength and Reliability of a Brushite Bone Cement
Authors: Mahmood S. , Palin W.M. , Gbureck Uwe , Addison O. , Hofmann M.P.
Published: March 2009

The effect of mechanical mixing on compressive strength, relative porosity and reliability
of strength data of a brushite forming cement at different powder to liquid ratios (PLRs) was
investigated. Mean compressive strengths were measured, associated reliability (Weibull moduli)
and survival probability distributions of the data sets were analysed. Relative porosities were
determined using helium pycnometry. For low PLR (2.2g/ml), no significant differences in
compressive strength were observed for either mechanical or hand mixed samples, although
reliability of the former was significantly increased. At high PLR (3.4g/ml), mechanically mixed
cements exhibited approximately twice the mean compressive strength compared with hand mixing,
although Weibull moduli remained statistically similar. At medium PLR (2.8g/ml) strength and
reliability of cements were similar and independent of mixing regime. For all PLRs, a significant
decrease in porosity of mechanical- compared with hand-mixed cements was observed. Mechanical
mixing of a brushite cement can provide lower porosity, increased reliability and higher strength.
Synthesis Bone Mineral (SBM) for Osteoporosis Therapy: Part 1 - Prevention of Bone Loss from Mineral Deficiency
Authors: LeGeros Racquel Z. , Mijares Dindo Q. , Yao Fang , Tannous Samar , Catig Gary , Xi Qing , Dias Renata , LeGeros John P.
Published: March 2009

Osteoporosis is a ‘silent’ disease characterized by thinning cortical bone and disorganized trabecular architecture causing bone fragility leading to fracture. Osteoporosis results when the rate of bone resorption far exceeds the rate of bone formation. Current pharmaceutical interventions (estrogen therapy, bisphosphonate-based drugs) focus on inhibiting bone resorption. However, some of these therapies have serious side effects (e.g., cancer risk from estrogen therapy; osteonecrosis of the jaw and delayed fracture healing from bisphosphonate-based drugs). The long term objective of the study was to develop a novel material for potential osteoporosis therapy, prevention and fracture repair. This novel material MZF-CaP or synthetic bone mineral, SBM) incorporates Mg, Zn and F ions in a calcium phosphate matrix. Separately, magnesium (Mg), zinc (Zn) and fluoride (F) ions have been associated with biomineralization and osteoporosis therapy in human and in animals. MZF-CaP or SBM was prepared by a modified hydrolysis method previously described and characterized using x-ray diffraction, FT-IR spectroscopy, inductive coupled plasma and dissolution in acidic buffer. Separately, male and female Sprague-Dawley rats were randomly assigned to the following groups depending on the diet: GA: normal on basic diets; GB: on mineral deficient diets (md); GC: on md + Mg-CaP; GD: on md + Zn-CaP; GE: md+F-CaP; and GF: md+MZF-CaP. The rats were sacrificed after 3 months and the femur bones separated, cleaned of extraneous soft tissues and stored until needed for analyses. Femur bones were analyzed using microradiography (Faxitron), scanning electron microscopy (SEM) and microCT. Results: SEM, Faxitron and microCT analyses showed thinning of cortical bone and disorganized trabecular bone architecture for osteoporotic rats on mineral deficient diet (GB) and prevention of bone loss in rats receiving the supplemented diets (GC,GD,GE,GF). Conclusion: These results indicate that the novel material, MZF-CaP or SBM had a potential for osteoporosis therapy and prevention. Studies to demonstrate the use of SBM in reversing (recovering) bone loss are in progress.
A Review of Two Animal Studies Dealing with Biological Responses to Glass-Fibre-Reinforced Composite Implants in Critical Size Calvarial Bone Defects in Rabbits
Authors: Tuusa Sari , Peltola Matti , Tirri Teemu , Lassila Lippo , Vallittu Pekka K.
Published: March 2009

In these studies, E-glass-fibre-reinforced composite (FRC) implants with
photopolymerisable resin systems and bioactive glass granules (BAG) were evaluated as a
reconstructive material in the critical size bone defects made to rabbits’ calvarial bones. In the first
study, a new experimental resin system, DD1/MMA/BDDMA, was used to impregnate the doubleveil
FRC-implants, while in the second study, a commercial resin system composed of
BisGMA/MMA/PMMA was used in impregnation. These double-veil FRC-implants were coated
with bioactive glass granules (BAG, 315-500 0m). In the second study, an experimental FRC
consisting of two laminates of woven fibres, was also tested as an implant material. These implants
were filled with BAG-granules and pure fused quartz fibers (Quartzel wool). In the first study,
implantation time was 4 or 12 weeks, while in the second study, it was 12 weeks for both the
implant types. Results: In the first study, the healing of the defects had started in the form of new
bone growth from the defect margins, as well as small islands of woven bone in the middle of the
defect, at 4 weeks postoperatively. Ingrowth of dense connective tissue into the pores of the implant
was widely seen. At 12 weeks postoperatively, more bony islands were seen as compared to the
animals studied at 4 weeks. Part of the newly formed bone had an appearance of lamellar structure.
The porous structures of the implant were deeply filled with fibroconnective tissue. Ingrowth of
maturing bone to the implant structures was occasionally seen. The inflammatory reaction was
moderate, and was mostly found inside the upper part of the implant. In the second study,
inflammatory reactions caused by both types of the FRC implants were very slight. Small amount
of new bone had started to grow from the defect margins in doulble-veil implanted defects. No
ingrowth of connective tissues or new bone formation was seen inside these implants. Instead, both
the connective tissues and newly formed, mineralizing bone were seen inside the experimental
double-laminate implants. SiO2-fibres seemed to cause moderate inflammatory reaction inside the
implants, while BAG granules did not. In both the study groups, the brain tissue was oedemic, but
no obvious serious damage was found. Conclusions: The structural properties of the FRC-implants
had an influence on the healing process of the bone defect. BAG, as a constituent of the FRCimplants,
enhanced the bone formation process. After some modifications to the properties of the
FRC, this type of implant has possibilities to become one material alternative in clinical bone defect
reconstruction at the craniofacial area in the future.
Optimisation of the Aqueous Precipitation Synthesis of Silicate-Substituted Hydroxyapatite
Authors: Hadden D.J. , Skakle J.M.S. , Gibson Iain R.
Published: March 2009

Silicon-substituted hydroxyapatite (SiHA) bioceramics are widely used as bone
replacement materials. There are various synthesis methods used to produce SiHA samples using
different sources of silicon. This study aims to investigate the role of tetraethyl orthosilicate (TEOS)
as the silicon source in the precipitation reaction synthesis of silicate-substituted HA. Four different
synthesis methods were studied by changing the order of addition of the TEOS solution during the
precipitation reaction. XRD and QXRD were used to determine the phase purity of the prepared
samples. FTIR and SSNMR were used to assess silicon/silicate substitution in the prepared
materials. Of the initial four methods used, only one resulted in a sample that was phase pure. The
other three syntheses, which produced biphasic compositions, were modified and a further single
phase sample was prepared. Results showed that the final composition is strongly dependant on
how and when the TEOS was added during the precipitation reaction.
Material Parameters in the System Al2O3-ZrO2
Authors: Begand Sabine , Oberbach Thomas , Glien Wilfried
Published: March 2009

The aim of the examinations was to produce various dispersion ceramics in the range of
0 -100% Al2O3, and to determine the strengths and selected characteristics such as density, fracture
toughness KIC, thermal conductivity, elastic modulus and hardness. Furthermore, the phase
composition of all samples was examined by means of X-ray diffraction following Rietveld
refinement. The examinations showed that the material parameters can be specifically influenced by
the corresponding adjustment of the ZrO2 portion. The utilisation of the effects of the dispersion and
transformation reinforcement can be exploited particularly with the mixture 20 % Al2O3-80
ZrO2(Y-TZP). Significant differences between the two forming procedures – slip casting and
pressing – could not be established.
Investigation of the Chip Types in High Speed Machining of SKD11 Steel
Authors: Lin Shen Yung , Cheng S.H.
Published: March 2009

High speed machining is very popular and widely used in industry recently, and it has
been accepted as a key technology for die and mold steel manufacturing because it has much
advantage as compared with conventional machining such as low cutting resistance, low cutting
heat generation and high production rate, etc. The finite element method is utilized in this study to
simulate the processes of chip formation during high speed machining of SKD11 die steel
workpiece step by step from an incipient of tool-workpiece engagement to a steady state of chip
formation. The effects of different combinations of cutting conditions such as cutting velocity, feed
rate, rake angle and nose radius of the tool on the curly types of chip formation are investigated
thoroughly for establishing the related skill for high speed machining or for predicting the chip
morphology in advance.
Research on Coupling Technique of Q-Switched Laser with Fiber
Authors: Song Gui Cai , Quan Wei , Cai Yun Song , Wu Hai Qing
Published: March 2009

The coupling of laser with fiber has been used for many fields: such as industry, medical
treatment, and communications. At the present time, the coupling methods are direct coupling and
lens coupling mainly. With the existence of a damage threshold in fiber end face and interior, it
very difficult to use the above ways to realize the coupling of high-power, high-energy and narrow
pulse laser with optical fiber. In this paper, a new method to reducing laser power density and
energy density in optical fiber end face and interior is presented and designed a hollow cone shaped
laser-fiber coupler by analyzing the mechanism of damage of optical fiber. When cylindrical Gauss
beam incident into the hollow cone coupler will form a light spot, the energy density is of quasiaverage
distribution. By using this coupler, we realized the coupling of a high-power (10MW),
energy (12mJ), narrow pulse (12ns) and electro-optical Q-switched Nd:YAG laser with the
multimode optical fiber (diameter is 600μm) and the coupling efficiency is 70%.
General Study on the Dimming Control of the LED Lighting Device
Authors: Cheng Yee Kwan , Cheng Ka Wai Eric , Shi Zhang Hai
Published: March 2009

Dimming control is used for energy saving scheme in most of the general lighting system. There are different kinds of dimming control methods in the lighting device. This paper aims to provide a general discussion on the power circuit to lighting up the LED devices and it also discusses the possible way to dim the LEDs. Moreover, this paper based on the 3W high power LED and aims to find out the best operating factors that can fully utilize LED and to provide best energy saving scheme.
Side-Emitting LED Lens Design for Generating Planar Lighting Source
Authors: Sun Yi Ting , Pao Yu Nan , Lin T.H.
Published: March 2009

Side-emitting LED (Light emitting diode) modulation lens is proposed here for generating planar lighting source that can be applied in many fields like LCD backlight or general lighting. The light emitted form the LED light source will be modulated by the proposed lens by the mechanism of multi-refraction. The optical simulation tool ASAP was used during the design procedure. Optimal lens dimension was designed to module 70 percent of the emitting energy to the angle range from 70 degree to 110 degree, the angle was calculated from the normal direction of the LED horizontal plane to the direction of the emitting light. The lens prototype was also fabricated and the optical performance was measured to verify the simulation results. Finally, the comparison between the optical simulation and the experiment performances is also disclosed.
The Optimization of Directly-Under-Light Type Backlight Module Structure for Brightness Uniformity
Authors: Chen Chi Feng , Lu Lea Ming
Published: March 2009

The optimization of the directly-under-light type backlight module structure for brightness uniformity is investigated. All structure parameters of the 32-inch LCD-TV backlight module are chosen by the ray-tracing method for the optimal brightness uniformity. It is shown that the brightness uniformity without optical sheets can be made as high as 87.3%.
A Fuzzy Algorithm for Auto-Focusing Laser Diode Products
Authors: Lee Kuang Chyi
Published: March 2009

The products of laser diode have been widely used, creating high profits. As there are
only semi-auto-focus machines to do the focusing-jobs for the products of laser diode, it takes much
work and increases the products’ cost. Therefore we developed a fully auto-focus machine for the
products of laser diode to promote the quality of products and reduce the cost of the products. The
AC servomotor was adopted to control the focus length. The image of the well-focused laser diode
point can present more accurate information than the blurred laser point. It is helpful to get precise
focus of laser diode. We adjusted the focus length of laser diode products by a fuzzy algorithm
according to the feedback image information. The feedback image of laser diode spot was
processed to distinguish the background, blurred region and bright region by a three-value
thresholding method. The image information of the laser diode spot, the area of the bright region
and the ratio between the blurred area and the bright area, were used as the criterion for the autofocusing
job and to judge whether the focusing-job was well-done. In the meantime, we could also
get the offsets in the x- and y- direction of the laser diode from the image of laser diode spot.
Finally, we adjusted the focus length and the offsets of the laser diode products by a fuzzy imaging
control algorithm to get the optimal focusing condition.
Diffractive Line Beam Shaper
Authors: Chen Cheng Huan , Chen Po Chou , Hsu Chin Ju , Ting Chia Jen
Published: March 2009

A diffractive laser beam shaper has been proposed as a lossless approach to transfer a Gaussian
laser beam into a thin line beam with a uniform distribution along the line direction for scanning material
processing or illumination application. With the consideration for the feasibility of fabrication, the optical
performance of the diffractive beam shaper with its surface relief quantized at different levels has been
analyzed with scalar diffraction theory, which shows that an 8 level solution is sufficient for keeping the
uniformity in the line direction while the focusing function in the orthogonal dimension needs to be
performed by an extra cylindrical lens.
Synthesis of ZnO Nanoparticles by a Novel Gas Condensation System
Authors: Chang Ho , Jwo Ching Song , Tsung Tsing Tshih , Fan Pei Shu , Wu Yan Chyuan , Tsai Ming Hsun
Published: March 2009

This paper describes an innovative system to produce nanoparticles based on the
theory of gas condensation in producing nanoparticles. In a vaccuum environment, the system
used the energy produced by high frequency induction to vaporize a pure zinc rod inside the
crucible. During the vaporization the chamber was filled with He gas, so the high-temperatured
vaporized metal can undergo momentum exchange with He gas and at the same time, induce the
vaporized metal to move to the cold trap. Upon reaching the wall of the cold condenser, the
vaporized metal instantly condensed, forming nanoparticles. The TEM image shows that their
average diameter was 30 nm, and the size was very consistent. In addition, the Zeta potential and
average diameter of the ZnO nanofluid was also measured under different pH conditions to
determine the stability of the ZnO nanofluid. Moreover, in order to verify the practicability of the
fabricated ZnO nanoparticles, the ZnO nanofluid was inspected by UV/Vis absorption spectrum,
and the results show that ZnO nanoparticles absorption ability was within a wavelength range from
350nm to 550nm.
Microstructure Optics Designed for LED Traffic Signal Lighting
Authors: Fok Lo Ming , Pun Min Hang , Louie Derek , Li Li Man
Published: March 2009

Optical lenses are used in signal lighting to control intensity distributions. Brightness and
viewing angle are two essential requirements that have to be considered in manufacturing a traffic
signal lamp. This paper discusses design considerations for microstructure optics designed for LED
traffic signal light, strategies for obtaining particular intensity distributions, optical functions of the
lens and matters concerning the manufacturing process. The mould inserts of the optical surfaces
were machined by CNC high-speed milling. Results of surface finish and profile accuracy analyses
using the Form Talysurf instrument are presented.
A Predictive Model Construction for the Sheared Planes in Sheet Metal Shearing Process
Authors: Hsu Yuan Chuan , Yang Tung Sheng
Published: March 2009

The shearing processes such as the blanking and piercing of sheet metals have been often
used to prepare workpiece for subsequent forming operation. The sheared plane plays an important
role in the shearing products’ dimension precision and their functions. The quality of sheared plane
is affected not only by the material characteristics but also by the process parameters. In the current
study, the finite element method is used to investigate the shearing process of sheet metals. Then,
the neural network was employed to construct the relationship model of shearing process
parameters related to the fracture depth of sheared plane, such as blank holding force, die corner
radius, punch-die clearance, friction factor and punch speed,. The result and approach obtained
from this study would be beneficial to stamping industries because they provide the reference for
the prediction of shearing process.
Experiment Research on Temperature Field in Ultrasonic Assisted Grinding Engineering Ceramics
Authors: Gao Guo Fu , Liu Chuan Shao , Zhao Bo , Jiao Feng , Kong Qing Hua
Published: March 2009

As one of the key factors grinding heat has a significant effect on the ground surface quality in grinding engineering ceramics using diamond grinding wheel. Differences between mechanical and physical performances of ceramic materials and grinding parameters have important influences on the surface temperature distribution. In the present research, experiments with/without ultrasonic assistance were carried out to study the temperature characteristics in the grinding field by thermocouple in grinding ZrO2 and Al2O3 engineering ceramics respectively. Moreover, the theoretical analysis and the experiment confirmation for the relationship between grinding parameters and temperature have been discussed. The results show that the further the heat source keeps against grinding surface, the lower the peak value of temperature, and the surface temperature increases with the grinding depth, grinding speed and work table speed. According to the results of orthogonal experiments on grinding parameters, the grinding depth is the most important factor affecting the grinding temperature on the workpiece surface.
Effect of the Adhesive Mass at the Cantilever Beam Tip Position
Authors: Yeh Yen Liang , Wang Cheng Chi , Jang Ming Jyi , Chen Kuang Sheng , Lin Yen Pin
Published: March 2009

This study employs finite element simulations to investigate the relationship between the
equivalent mass and the real mass of end masses adhered to the tip of the cantilever beam of an
atomic force microscope. The equivalent mass was determined by analyzing the variation in the
resonant frequency of the cantilever beam caused by the addition of the end mass. The analysis
considered five different adhesive mass materials, namely copper, aluminum, S45C steel, titanium
alloy and magnesium alloy. Furthermore, the analysis also considerd the effect of the position of the
adhesive mass on its equivalent mass value. The numerical results indicate that the equivalent
adhesive mass is less than the real adhesive mass. The ratio of the equivalent adhesive mass to the
real adhesive mass is approximately constant for a given adhesive position and adhesive material
and has a value of approximately 0.6361 for a high-density material. Finally, the results show that
an offset of the adhesive mass from the tip position causes a slight change in the value of the
equivalent mass to real mass ratio.
Experimental Techniques to Characterize Large Plastic Deformations in Unlubricated Hot Aluminum Extrusion
Authors: Valberg Henry Sigvart
Published: March 2009

A review is given of experimental work done at the author’s university during the last
two decades, to investigate metal flow in aluminum extrusion.
Partially extruded billets with internal grid patterns are difficult to remove from the container
without post-deforming the internal pattern during the removal operation. A technique was
therefore developed by which such billets can be removed from the container without any damage.
In addition to this, a special grid pattern technique was developed. This technique applies contrast
material stripes in the symmetry plane of the billet, and is advantageous because the pattern
obtained remains clearly visible after extrusion, even in shear zones subjected to very heavy
deformations. Traditional scratched patterns become invisible in such regions, and do not provide
metal flow information in shear zones.
When the two techniques, i.e. the new removal technique and the new grid pattern technique, were
used concurrently, “perfect” type of metal flow experiments were conducted.
A three-dimensional grid pattern technique was also developed. It is well suited for characterization
of metal flow in complex shape extrusion, when there is no symmetry plane in which to conduct
traditional grid pattern analysis.
Applications of the new techniques for metal flow studies in various cases of extrusion are reported.
It is shown that precise metal flow information indeed is a necessary requirement to get metal flow
correct in computer simulation.
Flow Front Tracking in ALE/Eulerian Formulation FEM Simulations of Aluminium Extrusion
Authors: Koopman A.J. , Geijselaers H.J.M. , Huétink J.
Published: March 2009

Even though Extrusion is often regarded as a semi stationary process, the defor-
mations of the die at the beginning of the process can have great influence on the process later
on. During filling of the die, the deformation of the die depends on the location of the flow
front up to a point where parts of the profile will be opened or closed, especially in porthole
dies. In this paper we present an accurate 2D method to simulate the filling of extrusion dies.
The method is based on the pseudo concentration technique. We compare different options to
model the pseudo material and choose the best.
Fabrication of Porous Transpiration C/SiC Composites
Authors: Ji Hong Liang , Zhang Chang Rui , Zhou Xin Gui , Cao Ying Bin
Published: March 2009

A new technology, prefabricating pore media (PPM) technology that adopt glass fiber as pore media, for porous transpiration cooling C/SiC composites was studied. The result shows that the technology can control the pore structure successfully by the volume content and distribution of glass fiber in the braid, and the porous C/SiC composites have good bending strength above 300MPa.
Tribological Performance of Ultra-Hard Ceramic Composite Coatings Obtained through the Microplasma Oxidation
Authors: Li Shu Hua , Wang Fu Chi , Yin Yu Jun , Yang Run Ze , Tan Cheng Wen
Published: March 2009

Ceramic oxidation coating of approximately 60 m thick was prepared on a Ly12 alloy substrate by micro-plasma oxidation in an alkali-silicate electrolytic solution. Coating thickness was measured during coating formation. The influence of current density, electrolyte temperature and inter-electrode distance on coating kinetics was investigated. Microstructure and phase compositions were analyzed. The micro-hardness of the coating was also measured. The tribological performance of the coatings was evaluated using a dry sand abrasion test. In addition, the results are compared to detonationsprayed alumina coating.
Microwave Hydrothermal Synthesis of Nanosize TiO2
Authors: Zhou Ze Hua , Li Wen Kui , Chen Zhi Qin
Published: March 2009

Nanocrystalline titanium dioxide was synthesized by microwave hydrothermal (MH) using
tetrabutyl titanate and normal butyl alcohol as start materials. The mixture solution of tetrabutyl titanate
and normal butyl alcohol in 1:1.5 molar ratio was processed in a microwave hydrothermal digestion
system at 200oC for 20 min to prepare nanosized TiO2 powders. The results showed that the microwave
assisted reactions proceed at a faster rate than the traditional hydrothermal methods. The powder was heat
treated at 500oC and the final products is ~20 nm in size and well dispersed.
Adsorption of Soluble Metal Ions from Red Mud by Modified Activated Carbon
Authors: Zhou Hua Lei , Li Dong Yan , Gong Guo Zhuo , Tian Ya Jun , Chen Yun Fa
Published: March 2009

Activated carbon was employed as the adsorption carrier for the metal ions in HCl solution of
red mud, a solid waste produced in alumina industry. To improve the adsorption capacity to valuable
metal ions, the activated carbon was modified by chemicals including HNO3, H2O2, H2SO4, H3PO4, NH3,
Na2CO3, and tri-butyl phosphate (TBP). It was found that the modifications contributed the high
adsorption capacity to almost all metal ions we focused on. In the case of TBP, remarkably higher
adsorption capacity and selectivity of Sc3+ was observed. The correlation between the surface areas, IR
spectra of those chemically modified activated carbons and adsorption was schemed.
Interface Microstructure of TiC Cermets/Steel Explosive Cladding Plate
Authors: Li Yan , Wei Shi Zhong , Gao Jian Ping , Zhang Wan Hong , Long Rui
Published: March 2009

Microstructure in anchoring site of TiC cermets/steel explosive cladding plate was analyzed by
transmission electron microscope (TEM), scanning electron microscope (SEM) and energy-dispersive
spectrometer (EDS). An intermittent micro-crystal layer, with thickness of about 10μm, was observed in
anchoring area. The inner crystal size was in range of some nanometer to hundreds of nanometer. The
phases of the layer are mainly austenite, ferrite, and some titanium carbide. A flow layer was observed in
the area near the steel side. The diffusion of Ti is the most apparent and the diffusion length is about
15μm. The observation of the microstructure in anchoring area revealed the nature of explosive
compound in metallurgical anchoring.
Damage Model and Failure Stress of Ceramic Particle Ni Base Alloy Composite
Authors: Zheng Jian , Ni Xin Hua , Kang Jing Xin
Published: March 2009

For Ceramic particle Ni base alloy composite, experiments and damage evolution finite
element analysis shows that arc-microcracks happen only at the interfaces between the particles and
matrix, and then extend to the matrix. Composite strength is coincident with matrix failure. First, the
three-phases model is used to determine the external strains of two-phases element. Then
micromechanical stress field in the matrix is obtained. Based on the generalized thermodynamic force in
damage process, the damage equivalent stress can be computed. As the damage equivalent stress is equal
to the ultimate stress of the matrix, the failure stress of matrix in composites is given.
Characteristics and Mechanisms of Dynamic Oxidation for ZrB2-SiC Based UHTC
Authors: Han Jie Cai , Hu Ping , Zhang Xing Hong , Meng Song He
Published: March 2009

The present study focuses on the dynamic oxidation resistance of five representative ZrB2-SiC
based ultra-high temperature ceramics (UHTCs): ZrB2-SiC, ZrB2-SiC-Si3N4, ZrB2-SiC-TiB2, ZrB2-SiCHfB2
and ZrB2-SiC-ZrC using oxyacetylene torch and arc jet testing. The effects of second phase incorporation
(Si3N4, TiB2, HfB2, ZrC) on oxidation resistance were compared and analyzed. The mechanism of
oxidation based on experimental results and thermodynamic calculations were explored. Some
approaches to improvement of oxidation resistance and future directions of UHTC are also presented.
Effect of the Rare Earth Oxides on Sintering Behavior and Microstructure of ZrB2-SiC Ceramics
Authors: Li Xue Ying , Han Jie Cai , Zhang Xing Hong , Luo Xiao Guang
Published: March 2009

In this study, two rare earth oxides, Y2O3 and La2O3, are used as the additives in the sintering of
ZrB2-SiC composites to improve the sinterability and control development of microstructure during
densification. The results show that the use of rare earth oxides (5vol.%) improves the powder
sinterability, hindered excessive growth of matrix particles and increase fracture toughness of ZrB2-SiC
composites, in comparison to ZrB2-SiC with additions free. Nearly full dense materials are obtained by
hot pressing at 1900°C. XRD analyses indicate that lanthanum-containing phases were formed in the
composite with La2O3. Microstructure observations by SEM reveal that the grain size of ZrB2-SiC with
Y2O3 and La2O3 composites are less than the sample without additives, which indicates Y2O3 and La2O3
may restrain the grain growth and increase the fracture toughness. The fracture toughness of ZrB2-SiC
composites with Y2O3 and La2O3 reached 5.0MPa·m1/2 and 5.5MPa·m1/2 respectively. Therefore, the
additive Y2O3 and La2O3 are very effective as sintering aids for the ZrB2-SiC composite.
Microstructure of ZrB2–SiC Composite Fabricated by Spark Plasma Sintering
Authors: Cao Jian Ling , Xu Qiang , Zhu Shi Zhen , Zhao Jun Feng , Wang Fu Chi
Published: March 2009

ZrB2-SiC composite is a promising candidate for ultra-high temperature ceramics, which is
difficult to be sintered due to strong covalent bonding of ZrB2 and SiC. ZrB2-30Vol.%SiC composite was
prepared by spark plasma sintering technique (SPS) at the sintering temperature of 1850°C, sintering
pressure of 50MPa, heating rate of 200°C/min and holding time of 3 minutes. The phase components and
microstructure were examined by X-ray diffraction, scanning electron microscopy and transmitting
electron microscopy. The results show that the product is composed of ZrB2 phase, SiC phase and ZrO2
phase. A rationalization for the presence of ZrO2 phase is based on the impurity of raw material and
oxidation of ZrB2 during SPS. The consolidated product is very dense and no apparent pores exist in the
microstructure. ZrO2 phase with irregular shape is found among some particles as a binder phase. It is
shown that the presence of ZrO2 phase may be beneficial to the densification of ZrB2-SiC composite.
Preparation and Properties of 2D C/SiC-TaC Composites
Authors: Zhang Yu Di , Zhang Chang Rui , Hu Hai Feng , Zhou Yong Lian
Published: March 2009

Ultra high temperature ceramic matrix composites (UHTCC) are being considered as the most
promising materials for leading edge and nose cap of hypersonic spacecrafts, reusable space vehicles and
so on. In the paper, 2D carbon fiber cloth reinforced silicon carbide-tantalum carbide (2D SiC-TaC)
UHTCC was fabricated by slurry-pasting and precursor infiltration pyrolysis process (PIP). Influences of
the volume ratio (10, 20, 30, 60, 80 and 100%) of TaC powder on mechanical properties and ablative
resistance of 2D C/SiC-TaC composites were studied. The results showed that the relative density of
composites with 60vol% TaC powder was the highest, the flexural strength of the composites reached
356MPa and the mass loss rate and recession rate were 0.0116g/s and 0.026mm/s respectively, while
those of C/SiC composites were 0.0166g/s and 0.062mm/s respectively. Moreover, the higher TaC
powder content, the smaller the fracture toughness of the composites was. The fracture toughness of the
2D C/SiC-TaC composites with 100vol% TaC powder was only 8.69 MPa-m1/2, while that of C/SiC
composites was over 15.0 MPa-m1/2.
Effect of Silicon Carbide Interlayers on the Mechanical Behavior of T800-HB-Fiber-Reinforced Silicon Carbide-Matrix Composites
Authors: Zhou Xin Gui , Yu Hai Jiao , Huang Bo Yun , Yang Jian Gao , Huang Ze Lan
Published: March 2009

The influence of the fiber/matrix interlayers on the mechanical properties of T800-HB fiber (a
kind of carbon fiber) (the fibrous is three-dimensional four-directional braided) reinforced silicon carbide
(SiC) matrix composites has been evaluated in this paper. The composites were fabricated through PIP
process, and SiC layers were deposited as fiber/matrix interlayers by the isothermal CVD process.
Fiber/matrix debonding and relatively long fiber pullouts were observed on the fracture surfaces. The
mechanical properties were investigated using three-point bending test and single-edge notched beam
test. The T800-HB/SiC composites exhibited high mechanical strength, and the flexural strength and
fracture toughness were 511.5MPa and 20.8MPa•m1/2, respectively.
Joining CoSb3 to Metal Surface of FGM Electrode for Thermoelectric Modules by SPS
Authors: Sui Tao , Li Jing Feng , Jin Song Zhe
Published: March 2009

The fabrication of electrodes is one of the key techniques in constructing thermoelectric
elements for the practical applications. In this work, the commercial active brazing alloy “Incusil-ABA”
was used for the joining of CoSb3 to the Cu surface of the graded electrode materials (Cu/AlN/Cu) by
using spark plasma sintering (SPS). The bonding was performed in vacuum at temperatures 500°C for
10min. The brazing and diffusion bonding process were investigated by analyzing the crystal structure
and microstructure of the bonding interface using X-ray diffraction and scanning electron microscopy,
and its composition distribution was also analyzed by energy dispersive X-ray.
Preparation and Characterization of High Textured KSr2Nb5O15 Lead-Free Piezoelectric Ceramics
Authors: Xie Li Jin , Xu Gao Jie , Li Zhi Xiang
Published: March 2009

Anisometric KSr2Nb5O15 (KSN) particles were synthesized by molten salt method with SrCO3,
Nb2O5 and KCl as raw materials. With K2CO3, SrCO3 and Nb2O5 starting materials, KSN lead-free
piezoelectric ceramics were prepared by conventional ceramics technique and reactive templated grain
growth (RTGG) method, respectively. In the RTGG process, green compacts were fabricated by tapecasting
using anisometric KSN as template particles. The KSN particles prepared by molten salt method
were rodlike in shape and dense. The KSN ceramics prepared by RTGG not only had higher degree of
grain orientation but higher sintered density compared with that prepared by solid-state reaction.
Ultrasonic Linear Motor with a High Stiffness Support Mechanism for Precision Control
Authors: Yun Cheol Ho , Kim Wan Soo , Cha Hyun Rok , Jung Tea Uk , Lee Sun Kyu
Published: March 2009

New holding mechanism is proposed to improve the positioning capability of ultrasonic linear
motor based on previous researches proposed by the authors. Through the previous holding mechanism
using a resonance system, the remarkable operating stability and controllability at high-power driving
were achieved. However, when higher power is demanded, big noise in supporting parts of a resonance
system is generated and these parts could be damaged and worn due to the discordance of a resonance
frequency between a transducer and supporting horns. Also the coupling problem of two vibration modes
remains because of using a half wavelength. This research proposes a new design of ultrasonic motor with
three supporting points in one vibrator for high stiffness support and discusses the solution about the
coupling effect and the nano-level positioning capability. Finally, a maximum driving mechanical force
and the positioning accuracy were achieved over 75 N and 100 nm through this mechanism. Moreover,
the efficiency of motor was 35% when the trust force was 52 N and the velocity was 0.27 m/s.
A Novel Piezoelectric Micro-Motor Using Multilayer Co-Firing Piezoelectric Ceramics
Authors: Ji Ye , Chu Xiang Cheng , Li Long Tu , Gui Zhi Lun
Published: March 2009

A novel rotary piezoelectric micro-motor (φ8mm×10mm) is proposed in this paper. Different from the conventional traveling wave ultrasonic motor using piezoelectric ceramic ring, four multilayer co-firing piezoelectric ceramic bulks (2mm×2mm×3mm) are used to generate vibration in the ring type stator. The layout and electric signals applied to the piezoelectric ceramic bulks are designed for the purpose of generating elliptical trajectories on the surface of the stator. The working mode of the prototype motor is simulated by the finite element method, and also measured by the Doppler Laser Vibrometer. The experimental results are in good agreement with simulation, which verifies the effectiveness of the finite element model. The prototype motor is driven at the low voltage of 12V under the frequency of 64.91 KHz.
Magnitude Versus Frequency Performance of Vibration Acceleration Sensor Based on Cymbal Transducer
Authors: Li Deng Hua , Yang Shu Hui , Gao Jing Min , Ma Yong Cheng
Published: March 2009

The magnitude versus frequency performance for a vibration acceleration sensor based on metal-ceramic piezocomposite transducer (cymbal) was studied in this paper. The results showed that the voltage sensitivity of this new sensor is as a function of not only the effective piezoelectric coefficient, d33 e, elastic coefficient, ky, and the resonance frequency, f0, of the cymbal transducer, but also the relative damping coefficient, ξ, of this new sensor. The relative damping coefficient, ξ, is also as a function of the capacitance, C0, of the cymbal transducer and a function of the mass, m, of the sensor, which is used as a prestressing force. The magnitude versus frequency plot for this vibration acceleration sensor was constructed. The results showed that the magnitude versus frequency performance of this new sensor changes as the relative damping coefficient, ξ, varies. The magnitude versus frequency performance is not dependent on the relative damping coefficient, ξ, when the ratio of operation frequency to the nature frequency, ω /ω0, is less than 0.2.
Microwave Sintering of YSZ Electrolyte Materials for SOFC
Authors: Wang Xi Tang , Kale Girish M.
Published: March 2009

Microwave sintering behaviors of four different compositions of YSZ electrolyte materials were investigated. The samples were sintered in 2.45GHz microwave furnace. For comparison, conventional sintering was performed at 1821K.The densities of sintered samples showed considerable enhancement in the densification process under the influence of microwave fields. The samples with lower Y2O3 content are easy to sinter. The influence of the composition and sintering methods on the final phase composition and microstructure were investigated by X-ray diffraction and scanning electron microcopy. Finer and more uniform microstructures were observed in the microwave sintered samples comparing to the conventionally sintered samples.
Effect of Mn–Doping Content on the Microstructure and Crystallite Size of LiNi0.85-xCo0.15MnxO2 Cathode Materials
Authors: Gu Yi Jie , Wang C.L. , Cui Hong Zhi , Wu H.K. , Huang X.W. , Liu X.B. , Wang Y.M. , Yang Z.N. , Huo H.
Published: March 2009

A series of Mn-doped LiNi0.85−xCo0.15MnxO2 compounds (x= 0, 0.1, 0.2 and 0.4) were prepared by the co-precipitation method. The effect and mechanism of Mn–doping on the microstructures and crystallite sizes of LiNi0.85−xCo0.15MnxO2 cathode materials were studied. The non-equivalent substitution of Mn ions for Ni ions induces a decrease in the average valence of nickel ions. The Mn-doping promotes the formation of the single phase compounds with more ordered structure.
Rate Capability Fade of 18650 Li-Ion Cells
Authors: Lian Fang , Li Yan , Hu Yang , Zhong Sheng Wen , Xu Li Hua , Liu Qing Guo
Published: March 2009

The rate capability of 18650 lithium-ion cells was studied in the paper. The experimental results showed that the reversible capacity declined to 89.5, 85.8 and 81.2% of the initial capacity after 300 cycles at discharge rate of 0.5, 1 and 2C, respectively. The XRD and SAED analysis indicated that at a high current density partial positive electrode material LiCoO2 transformed gradually from well-layered structure to rock salt cubic crystal. Upon the cycling, the degradation of cathode materials’ structure and much thicker negative film on anode electrode surface contributed to the rate capability fade.
Synthesis of Ultrafine GSAG:Ce Phosphor by Solution Combustion
Authors: Zhang Cheng , Liao Yi Kun , Jiang Dan Yu
Published: March 2009

Ultrafine cerium-doped GSAG phosphor powders are prepared by a solution combustion
process using glycine and urea as fuel. Single-phase cubic GSAG:Ce crystalline powder is obtained by
calcining the as-synthesized amorphous materials at 800oC and no intermediate phase is observed.
Transmission electronic microscope morphology shows that the resultant GSAG:Ce powders have
uniform size and good homogeneity. The photoluminescence spectra of Ce3+ substituted for Ce3+ in
GSAG has been measured on samples calcined at 1000oC.
Fabrication and Luminescence Properties of Y2SiWO8:Dy3+ Phosphors via Sol-Gel Process
Authors: Han Xiu Mei , Lin J. , Yu M. , Lin C.K. , Qi Xi Wei , Li Ming Ya , Wang Xiao Qin
Published: March 2009

Y2SiWO8:Dy3+ phosphors were prepared through a sol-gel process. XRD and photoluminescence spectra were used to characterize the resulting phosphors. The results indicated that the phosphors crystallized completely at 1000°C. In Y2SiWO8:Dy3+ phosphors, the Dy3+ showed its characteristic yellow emission at 483nm (4F9/2-6H5/2) and 575nm (4F9/2-6H13/2) upon excitation into 275nm.
Sinterability of Nd:YAG Powder Prepared by Alcohol-Water Co-Precipitation Method
Authors: Tong Shi Hong , Lu Tie Cheng , Guo Wang , Xu Hui , Li Yong Chao , Fang Rui Xiao
Published: March 2009

Pure-phase 2at% Nd:YAG powder was synthesized by alcohol-water co-precipitation method. 2at% Nd:YAG ceramics were sintered at 1780 °C for 10 h under vacuum using the powder. Sintering ability of the powder was studied by comparing the results of alcohol-water solvent with those of distilled water solvent. The effects of different volume ratios of alcohol to water (R) on transparent ceramics have been also studied. Transparent ceramics having a transmittance of 40% in the visible wavelength have been sintered without sintering additive using the powder (R=0.8), which is much better than ceramics (16%) prepared using the powder derived from distilled water solvent under the same sintering conditions. In addition, the different R does not have much influence on the transmittance of ceramics in the present work. Compared with the results of distilled water solvent, the powders, using alcohol-water mixtures with different R as solvent, are more beneficial to the sintering of high transparent ceramics.
Co-Doped Tin Oxide Thin Films by Spin Coating
Authors: Li Jian , Liu Shan , Pan Wei
Published: March 2009

Co-doped tin oxide thin films were prepared using spin-coating method. Variation of doping
content on the magnetic property and optical property were measured. XRD and magnetic measurement
shows that Co solubility limit in SnO2 is less than 3%. When the doping content is lower than 3%, the
films show good optical transmittance. When the doping content is reached to 10%, the optical
transmittance became lower. When the solution is diluted, the optical transmittance drops more slowly.
Thermoelectric Properties of Bi2Te3 Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering
Authors: Zhou Min , Li Jing Feng , Liu Jing
Published: March 2009

The Bi2Te3 compound was synthesized by mechanical alloying (MA) of highly pure constituents of Bi and Te powders, and then was consolidated by spark plasma sintering (SPS) method. The MA-derived alloy formation was characterized by X-ray diffraction (XRD), and the microstructure change was investigated through scanning electron microscopy (SEM). The thermoelectric properties were measured using a Seebeck Coefficient/Electrical Resistance Measuring System. The influence of MA time on the thermoelectric properties of the SPS-sintered samples was investigated to find the optimal MA condition for the powder synthesis and thermoelectric properties. The obtained results showed that the sample with the MA time of 6 h exhibited the optimal electrical transport properties. The maximum power factor of over 2.0 × 10-3 W/m K2 was obtained between 323 K and 423 K.
Preparation of Nanosized Barium Ferrite Spinel by a Sonochemical Method
Authors: Liu Bo , Lv Wei Zhong , Luo Zhong Kuang , Ren Xiang Zhong , Cai Hong Hua , Zhang Pei Xin , Liu Jian Hong
Published: March 2009

Nanosized barium ferrite spinel particles were prepared with the aid of ultrasound radiation by a precursor approach. A precursor was got by sonicating an aqueous solution of BaCl2, Fe (NO3)3·9H2O and urea firstly. Nanosized BaFe2O4 particles with a size of ca.40nm were prepared after the precursor was heated at 950 °C for 15 h. The nanosized barium ferrite particles and the precursor were characterized by powder X-ray diffraction, scanning electron microscopy, FT-IR and differential scanning calorimetry.
Preparation of Zn1-xCoxO Diluted Magnetic Semiconductor by Hydrothermal Method
Authors: Li Hui Qin , Miao Hong Yan , Tan Guo Qiang
Published: March 2009

Zn1-xCoxO diluted magnetic semiconductor was prepared by hydrothermal method at 200 °C and 240 °C for 24h with the Co2+ doping content of 5~15 mol%. NaOH was used as the mineralizer. X-ray diffraction analysis indicated that the as-prepared Co-doped ZnO had the pure ZnO wurtzite structure. UV–Visible spectroscopy had shown that the Co ions are substituted to Zn ions in ZnO matrix. Room temperature VSM revealed a paramagnetic behavior of the Co-doped ZnO samples. FE-SEM analyses showed that nanocrystalline powders of pure Zn095Co0.05O and Zn09Co0.1O could be prepared by the hydrothermal method.
Control of Ceramic Material Microstructure with Super High Magnetic Field
Authors: Shui An Ze , Zeng Ling Ke , Liu Ping An , Cheng Xiao Su , Wang Hui
Published: March 2009

A new control method of the particle orientation structure with super high magnetic field is studied for Al2O3 ceramics. Al2O3 slurry was made with two types of Al2O3 particles, which one was spherical shape of, and the other one was elongated shape of. The Al2O3 ceramics of orientation structure was fabricated by drying the Al2O3 slurry under the super high magnetic field, cold isostatic pressing (CIP) and sintering. Effects of particle shape, particle size, the solid loading, slurry viscosity, dispersant content and the magnetic field strength on the particle orientation structure were examined in detail. The experimental results indicate that even the spherical Al2O3 particles can align under the magnetic field; the particle orientation degree changes with the particle shape and the solid loading under same magnetic field strength conditions, and the elongated particle system is easier to align than the spherical particle system; the particle orientation degree of the Al2O3 ceramics can be controlled by adjusting the particle shape, particle size, solid loading, slurry viscosity, dispersant content and magnetic field strength.
Effect of Temperature on the Synthesis of ZrO2-Mullite Powders in Molten Sodium Sulfate
Authors: Zhu Bo Quan , Li Xue Dong , Wang Hou Zhi
Published: March 2009

ZrO2-mullite compound powders were synthesized with zircon and aluminum sulfate in molten sodium sulfate. Na2ZrSiO5 was prepared as intermediate with zircon and sodium carbonate at 900°C for 3h. Then the mixture of resultant Na2ZrSiO5 and aluminum sulfate was heated at different temperatures in molten sodium sulfate salt. The ZrO2-Al2O3-SiO2 compound powders were obtained after washing away the solvable salts. The results showed that the compound powders synthesized at 800°C were tetragonal ZrO2, SiO2 and Al2O3; the powders synthesized at 1000°C were monoclinal ZrO2 and mullite. The mullite in compound powders became to decompose when the reaction temperature increased over 1100°C.