bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of High Efficiency Removal in the Grinding of Aluminal/ZrO2 Nanocomposites with the Aid of Two-Dimensional Ultrasonic Vibration
Authors: Wu Yan , Sun A.G. , Zhao Bo , Zhu Xun Sheng
Published: March 2009

Based on the single abrasive particle motion locus of elliptical spiral in two-dimensional ultrasonic vibration grinding (WTDUVG), the theoretical model representing the material removal rate are deduced and verified, and the reason of high efficiency material removal by applying two-dimensional ultrasonic vibration is analyzed. Finally, experimental researches on material removal rate of ceramics were carried out using coarse grit diamond wheel both with and without workpiece two-dimensional ultrasonic vibration assistance grinding. Experimental results indicated that (1) Material removal rate (MRR) in vibration grinding process is about 1.5 times as large as that of in conventional grinding, the experimental results are in good agreement with the calculated ones. (2)The material removal rate increases along with increases of the grinding depth and workpiece velocity both in with and without vibration grinding. (3)The vibration grinding surface had no spur and build-up edge and its surface roughness was smaller than CG significantly. Surface quality of WTDUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile regime grinding.
Micro-Cutting of Polytetrafluoroetylene (PTFE) for Application of Micro-Fluidic Devices
Authors: Hira Shin-Ichiro , Yoshioka Masato
Published: March 2009

This report describes fabrication of polytetrafluoroethylene (PTFE) to make up a
micro-fluidic device for the application to a Micro-Total Analysis System ( -TAS). This material is
chosen as a material of the device because of many excellent properties such as high chemical
resistance and high heat resistance in comparison with the other polymers. Mechanical micro-cutting
process is employed for the fabrications of the required elemental micro-structures such as a
micro-channel and a micro-reservoir for the device. In general, burrs are easily generated in the
cutting of soft materials such as PTFE. It is thought to be the most important to find how to prevent
the burr generation and how to clean the generated burrs to assure the device quality. Therefore, in
order to obtain the fundamental information about the burr generation in the micro-cutting of PTFE,
through hole drilling, groove milling and face milling are performed. As a result, the elemental
micro-structures without burrs are fabricated on PTFE plate. Furthermore the plate is sealed by
sealing film assisted with pressure. By testing leakage with fluid sample, it is confirmed that the
pressure-aided sealing is useful.
Preparation and Properties of PZT Bimorph on Metal Substrate by Hydrothermal Method
Authors: Du L.Q. , Lv Y. , Dong Wei Jie , Gao X.G.
Published: March 2009

Piezoelectric bimorph fabricated by hydrothermal method is presented in the paper. This
method is low cost, simple and easy. In order to describe the characteristics of piezoelectric
bimorph, properties of PZT film are studied by XRD and SEM. The ratio of PbTiO3/PbZrO3 in PZT
is 53/47, which is around morphotropic phase boundary (MPB). PZT film is composed of cubic
particles with the average size of 5μm. Density is figured out through the datum measured in
experiments. The model used to analyze the driving ability of bimorph is set up; piezoelectric
coefficient d31 of PZT film is worked out using this model. Finally, the ferroelectric property of the
bimorph is investigated and coercive voltage of the bimorph Vc =1.67V is obtained.
Ecological Deep Hole Drilling by Novel Coated and Designed Drill
Authors: Murakami Yoshihiko , Yamamoto Takahiro
Published: March 2009

Ecological deep hole drilling is proposed in this paper. The ecological drilling means a
cutting without coolant or minimum quantity lubrication (MQL). Under a cutting condition with a
small amount of lubrication, the drills should be designed availably to control heat generation during
cutting. An attempt is made on the development of innovative drills which are available for use under
ecological cutting conditions. These drills were coated especially with a titanium aluminum nitride
(TiAlN) film and a poly crystalline diamond layer. After TiAlN coating flutes of drills were lapped
with diamond compounds [1]. The result of studies on the process and application of the innovative
drills was reported.
OPG and Rankl Expression in Osteoblasts Grown on Different HA Ceramics
Authors: Wang Chao Yuan , Duan You Rong , Wang Xin Long , Markovic Boban , Barbara James , Howlett C. Rolfe , Zreiqat Hala , Zhang Xing Dong
Published: March 2009

Hydroxyapatite (HA) ceramics is one of the most widely used bone substitute in clinics. Limited information is available concerning how HA ceramics may affect osteoprotegerin (OPG) and RANKL expression. In this study, osteoblastic-like SaOS-2 cells were grown on HA ceramics sintered at different temperature for 3 and 6 days, RANKL and OPG mRNA expression were analyzed with quantitative in situ hybridization (QISH) technique. Result showed that SaOS-2 grown on HA ceramics sintered at 800°C expressed higher RANKL mRNA than on other two HA ceramics after 3 days’ culture. No significant difference in OPG expression on different surfaces was detected after 3 days and 6 days culture. This result suggests that HA sintered at low temperature tend to induce more bone remodeling after implantation.
Preparation of Porous Organically-Modified Silicate Hybrids for Cell Culture Matrix
Authors: Tsuru Kanji , Hayakawa Satoshi , Shirosaki Yuki , Okayama T. , Kataoka K. , Huh N.H. , Osaka Akiyoshi
Published: March 2009

Porous & rubbery organic-inorganic hybrids were synthesized from tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) through a sol-gel route using sieved sucrose granules as a porogen. The porous hybrids with a high content of PDMS behaved like polymer sponge. The porosity was over 90% irrespective of the hybrid composition and the pore diameter ranged from 100 to 500 μm. In the three-dimensional cell culture, mammalian cells were well cultured in the porous hybrids. The present results indicate that the hybrids may be a promising scaffold for developing such functional culture methods.
Tribological Properties of Nano-Al2O3/PEEK Composites
Authors: Xiong Dang Sheng , Lin Jian Ming , Liu Ling Ling
Published: March 2009

Wear is the primary cause of failure of joint replacement prostheses.
Poly(ether-ether-ketone)(PEEK) was reinforced with nano-Al2O3 particals of various mass fractions
in this study. The effect of nanometer Al2O3 mass fractions on the contacted angle of the reinforced
PEEK composites was investigated. Tribological properties of composites under distilled water and
physiological saline lubrication condition was measured. And the morphologies of the worn surfaces
were observed with optical microscope. The results shows that the wettability and wear resistance
were all improved with appropriate nano-Al2O3.The wear resistance of composites filled with 7%
nano-Al2O3 was the best under both distilled water and physiological saline lubrication. In addition, it
can be found that there is serious plough on the surface of pure PEEK. This indicated that serious
fatigue wear occurred on the worn surface of pure PEEK. Moreover, there are only light fatigue wear
on the worn surfaces of PEEK composites filled with nano-Al2O3.
The Corrosion Behavior of Titanium in Hydrogen Peroxide Solution with Various Additives
Authors: Xie Lei , Wang Xiao Xiang , Li Jian
Published: March 2009

The corrosion behavior of titanium in hydrogen peroxide solutions was studied by
measuring the titanium ions concentration using spectrophotometer. The influence of additives (K+
，
Ca2+
，Na+
，Mg2+
，Cl-
，HPO4
2-, H2PO4
- ) on the corrosion behavior of titanium was examined. The
results indicated that Ca2+ exhibited the highest inhibition to the titanium corrosion in hydrogen
peroxide solutions, while HPO4
2- behaved as an accelerator to the corrosion. It was suggested that
the Ca2+ was absorbed on the titanium surface to form a thin film of CaTiO3 or CaO2, and
consequently, inhibited the corrosion of titanium. The acceleration of the titanium corrosion in the
present of HPO4
2- was caused probably by the increased defect of surface oxide films after
absorption of HPO4
2- ions.
Combined Effects of Nano-Hydroxyapatite and NaF on Remineralization of Early Caries Lesion
Authors: Kim M.Y. , Kwon H.K. , Choi Choong Ho , Kim B.I.
Published: March 2009

A previous study reported that many supplements have been added to NaF mouthrinses
to improve the remineralization potential. Nano-hydroxyapatite (nano-HA) might also be suitable to
this purpose because these nano-size particles can penetrate the enamel pores. Moreover,
hydroxyapatite is similar to the inorganic component of teeth and is both bioactive and
biocompatible. The aim of this study was to evaluate the combined effects of a nano-HA and
fluoride mouthrinse on an early caries lesion in human enamel using an in vitro cycle
remineralization and treatment model. Forty-eight human enamel specimens, which had a Vickers
Hardness Number (VHN) of 25~45 were artificially demineralized for 48h. There were 8 treatment
groups (0%, 1%, 5%, 10% nano-HA in distilled water and the same concentrations of nano-HA in a
0.05% NaF solution). The specimens were incubated in an in vitro remineralization model. After
immersing the specimens into the treatment and remineralization solution for 12 hours each, the
VHN of each specimen was evaluated for total 24 hours. This step was repeated once again for total
48 hours. The enamel surfaces of all specimens were examined by Confocal Laser Scanning
Microscopy (CLSM) and SEM. The statistical significance of the data was identified by one-way
ANOVA followed by a Duncan’s studentized range test. A p value < 0.05 was considered
significant. The results showed that the degree of remineralization, as revealed by the VHN values,
was higher in the NaF groups than in the distilled water groups. The VHNs of the remineralized
enamel specimens for 48 hours were higher than after the 24 hours treatment. In addition, the level
of remineralization increased with increasing concentration of nano-HA and was more pronounced
in the NaF groups than the distilled water groups (p<0.05). The CLSM and SEM images nano-sized
particles attached to the enamel in the nano-HA treated groups. Nano-HA might play a synergistic
role in remineralization with a fluoride mouthrinse. However, more study will be needed to
determine the optimal condition of nano-HA and NaF mouthrinse for human use. In conclusion,
nano-HA in a 0.05% NaF mouthrinse can help remineralize an early caries lesion.
Histomorphometric Analysis of Sinus Augmentation Using the ICB and MBCP
Authors: Jang Hyun Seon , Park Ju Un , Yu Sang Joun , Jeong Moon Jin , Kwon Young Sun , Kim Byung Ock
Published: March 2009

The purpose of this study is to evaluate the new bone formation of sinus augmentation with using ICB (Irradiated Cancellous Bone & Marrow; Rockey Mountain Tissue Bank, Denver, Co) and MBCP (Micro-Macroporous Biphasic Calcium Phosphate;Biomatlante, France). Study population consisted of 4 patients with maxillary posterior edentulous dentition and ridge heights were less than 5 mm. ICB (Rockey Mountain Tissue Bank, Denver, Co) and MBCP (Biomatlante, France) is mixed with 50: 50. After 6 months, the bone biopsies were done with 2mm trephine bur from lateral window opening. Mean new bone formations were 26.84 %, the residual grafts were 4.92 and soft tissues were 67.98 %. The small number of biopsies did not permit analysis of statistical significance. The variability of individual patient factors do not permit definitive conclusions. The mixtures of ICB & MBCP were superior or comparable to another various bone alternative materials in new bone formation of sinus floor elevation.
Investigation of the Mixed Alkali Effect in a Range of Phosphate Glasses
Authors: Abou Neel E. A. , Ahmed I. , Knowles Jonathan C.
Published: March 2009

This study investigated the mixed alkali effect in a series of phosphate based glasses. These
glasses were of the composition 0.5P2O5-0.2CaO-0.3-xNa2O-xK2O where x=0 to 0.3 in steps of 0.05.
This study considered density measurements using Archimedes’s principle, thermal characterisation using
differential scanning calorimetry, phase analysis following crystallisation using X-ray powder diffraction
(XRD), and degradation studies combined with ion release. The results showed that these mixed alkali
glasses showed a linear decrease in density, with the ternary single alkali glass with 0.3mol K2O showing
a 3% reduction in density as compared to that with 0.3mol Na2O which correlated well with the
difference in ionic diameter and atomic weight of both cations. These glasses also showed intermediate
glass transition temperature (Tg) values, compared to those of the ternary single alkali glasses having the
same alkali oxide content, and the minimum Tg value was recorded for equimolar amounts of both alkali
oxides. However, they did not show any significant change in the degradation rate compared to the glass
with 0.3mol Na2O with the exception of the 0.25mol K2O glass. The single alkali glass with 0.3mol K2O
showed a significant increase in the degradation rate by an approximate one order of magnitude. For the
mixed alkali glasses with low molar concentration of K2O, only sodium phosphate-rich phases
[NaCa(PO3)3 and Na4Ca(PO3)6] were detected from XRD; at high molar concentrations however,
potassium phosphate-rich phases [KCa(PO3)3 and KPO3] were detected. At equimolar concentration of
both alkali cations, KCa(PO3)3 and Na4Ca(PO3)6 were identified. K+, Ca2+, and P3O9
3- release followed
the degradation behaviour where the highly degrading glasses with 0.25 and 0.3mol K2O released the
highest amount of these ions; however, there was no definite trend in the remaining glass compositions.
Preparation and Properties of Porous Apatite-Wollastonite Bioactive Glass-Ceramic
Authors: Xue Ming , Ou Jun , Zhou Da Li , Feng Dange , Yang Wei Zhong , Li Guanda , Liu Dan Ping , Wang Yan Song
Published: March 2009

The porous apatite-wollastonite bioactive glass-ceramic (AW-GG) was made from
nano-precursor powders derived from sol-gel process, and shaped by dipping method with polymer
foam. The physical-chemical properties, bioactivity and biocompatibility of the materials were
studied by means of TG, XRD, SEM, TEM and so on. The bioactivity was investigated in simulated
body fluid (SBF) and the biocompatibility was evaluated by co-culturing with marrow stromal cells
(MSCs). The result shows that: the particle size of the AW precursor powders is 40~100nm; porous
AW GC has three-dimensional pored structure with 300~500um macropores and 2~5um micropores;
the materials possess high bioactivity and biocompatibility. Porous AW GC may therefore have great
potential application as bone tissue engineering scaffold.
Effects of Polyethylene Glycol on Morphology of Bioactive CaO-SiO2 Gel
Authors: Kim Ill Yong , Ohtsuki Chikara , Kamitakahara Masanobu , Cho S.B.
Published: March 2009

CaO-SiO2 gels for bioactive organic-inorganic composites were prepared from
tetraethoxysilane (TEOS) and calcium nitrate tetrahydrate (Ca(NO3)2⋅4H2O) by a sol-gel method
with the addition of the various amount of polyethylene glycol (PEG). The effects of PEG on
morphology and bioactivity of the gel were investigated. The samples with the starting compositions
of Ca(NO3)2 : TEOS = 30 : 70 in molar ratiowere prepared with or without coexistence of PEG. All
the examined gels were obtained as a crack-free bulk bodies after gelation and aging. FT-IR spectra
of the prepared gels showed that the gels have similar contents of silanol groups regardless of the
amount of PEG. SEM observation showed that the gel consists of aggregates of 2-3 μm spherical
particles with a diameter of 2-3 μm when it was prepared with the addition of PEG at a molar ratio of
PEG : TEOS = 0.002 : 1, while it consists of aggregates of spherical particles with a diameter of 50
nm at a molar ratio of PEG : TEOS = 0.004 or 0.007 : 1. The size of the CaO-SiO2 powder can be
decreased with increasing the amount of the added PEG. All the samples, regardless of the amount of
the added PEG, formed apatite on their surfaces in a simulated body fluid (SBF) within 1 d. These
results suggest that bioactive fine spherical particles with various size can be obtained through sol-gel
processing under co-existence of appropriate amounts of PEG.
Rapid Wet Synthesis of Nano-Sized β-TCP by Using Dialysis
Authors: Liu Y.H. , Zhang Sheng Min , Liu L. , Zhou W. , Hu W. , Li J. , Qiu Z.Y.
Published: March 2009

Nano-sized β-tricalcium phosphate (nano-sized β-TCP) was synthesized by dialysis
process using Ca(NO3)2·4H2O and (NH4)2HPO4 as starting materials. The time needed for the whole
process is much shorter than other reported methods. In this new synthesis, dialysis was used to
remove the unwanted ions, and the removal efficiency of impurity ion was evaluated by comparing
the representative ion NH4
+ between the original slurries and deionized water outside of the dialysis
tube. The resulting powders were characterized by X-ray diffraction (XRD), fourier transform
infrared spectroscopy (FT-IR), and chemical analysis. Results showed the final products are pure
β-TCP. The pictures of high resolution-transmission electron microscope (HR-TEM) further
indicated that β-TCP crystals are around 100nm in diameter.
Preparation and Characterization of Calcium Metaphosphate Nanofibers via Electrospinning
Authors: Tadjiev Timur R. , Chun Sung Su , Kim Hong Mi , Kang Inn Kyu , Kim Suk Young
Published: March 2009

Bioresorbable calcium metaphosphate (CMP) nanofibers were produced by an
electrospinning technique. In order to produce the nanofibers, CMP sol was prepared by the mixing of
two precursors, such as calcium nitrate tetrahydrate (Ca[NO3]⋅4H2O) and triethyl phosphate (TEP,
[C2H5O]3PO), using methyl alcohol as a solvent. The Ca/P ratio of the mixture was set to be 0.50 to
produce stoichiometric CMP sol. At least 5 hrs of pre-hydrolysis of phosphorus precursor were
required to obtain β-CMP phase. Viscous solutions for the electrospinning were made by the mixing
of CMP sol and high-molecular weight polymeric solution at various ratios. The ratio of CMP sol and
polymer solution was controlled to obtain an appropriate viscosity for the electrospinning.
As-electrospun CMP nanofibers were dried in a drying oven at 70°C for 24 hrs and then heat-treated
at various temperatures at a ramp of 1°C/min in air for 1hr. The as-electrospun and heat-treated CMP
nanofibers were characterized using X-ray analysis, FT-IR, TG-DTA and SEM techniques. The
results showed that the preparation of CMP sol, mixed solution properties, and heat-treatment
condition of as-electrospun nanofibers significantly affect the spinability and surface morphology of
the CMP nanofibers.
Dialysis Preparation of Zinc-Substituted Nano-Hydroxyapatite and Its Characterization
Authors: Zhang Sheng Min , Hu W. , Zhou W. , Li J. , Liu Y.H. , Qiu Z.Y.
Published: March 2009

Nano-sized zinc-substituted hydroxyapatite (nano-ZnHA) has stimulatory effect on bone
formation and inhibitory effect on osteoclastic bone resorption in vivo. Nano-ZnHA with serial zinc fractions
(0, 2, 5, 10 mol%) were synthesized by an improved precipitation method based on dialysis process.
Transmission electron microscopy observation indicated that the increase of Zn fraction led to
smaller crystallite. X-ray diffraction of the products revealed that some typical characteristic peaks
of HA displayed when the Zn fraction was below 10%. Fourier transform infrared spectroscopy
showed that the bending peaks of the group-OH in HA became wider with the increase of Zn
fraction and it disappeared at 10 mol%. The current work demonstrated that zinc could substitute for
calcium into hydroxyapatite in the limited range of composition by using dialysis process.
Synthesis of Albumin/DCP Nano-Composite Particles
Authors: Ohsawa Hajime , Ito Atsuo , Sogo Yu , Yamazaki Atsushi , Ohno Tadao
Published: March 2009

Highly disgregated dicalcium phosphate anhydrate (DCP) nanoparticles 240-367 nm in diameter were synthesized by a reaction between calcium carbonate and phosphoric acid. When the DCP nanoparticles were immersed in a supersaturated calcium phosphate solution containing bovine serum albumin (BSA) and ethanol, BSA/DCP nano-composite particles were synthesized through the coprecipitation of BSA on the DCP nanoparticles. BSA was firmly immobilized on the BSA/DCP nano-composite particles. The results of this study suggest that DCP nanoparticles appear to be useful as a drug delivery vehicle.
Sintering Behaviour of Nanosized HAP Powder
Authors: Veljković Dj. , Jokic B. , Jankovic-Castvan I. , Smičiklas I. , Petrović R. , Janaćković Dj.
Published: March 2009

The influences of temperature and time on sintering behaviour of nanosized HAP powder
were investigate in this paper. The calcium hydroxyapatite powder, with the average crystallite size
of 34 ± 1 nm, was uniaxially pressed at a pressure of 500 MPa. Obtained green compacts were
sintered at temperature ranging from 1000°C to 1200°C in air atmosphere at various times.
According to the results of scanning electron microscopy, X-ray and FTIR analyses, it is shown that
HAP compacts with dense microstructure and average grain size below 250 nm is obtained.
Research about Tooth Whitening and Bacteria Sticking Capability with Using Dentifrice Including Nano-Hydroxyapatite, Sodium Metaphosphate
Authors: Park Yong Duk , Kim Ji Hwan , Hwang Kyung Sook
Published: March 2009

Hydroxyapatite has high affinity rate with organic substance in an oral cavity, therefore
lately nano-sized hydroxyapatite is extensively researched to increase affinity to tooth and
remineralization. The objective of this research is indirectly to investigate the effect of nanohydroxyapatite
on remineralization using valuation about whiteness and bacterial contamination of
the bovine tooth. We have designed in vitro test for this purpose. The bovine teeth are sliced into
human teeth size then the baseline whiteness of total 60 teeth is measured and assigned into 3
groups by cross-matching according to the whiteness. These samples were embedded into resin
mold and underwent mechanical brushing during fixed schedule. The whiteness and bacterial
contamination of teeth are measured and compared among 3 groups. Each dentifrice used in the
experiment is composed of B.S.I group (30% Calcium Carbonate, precipitated-CaCo3) with
abrasion rate of 100, Test Ⅰgroup (15% Sodium Metaphosphate, insoluble-NaPo3), Test Ⅱ group
(15% Nano-hydroxyapate-Ca10(PO4)6(OH)2. After 20,000 strokes of mechanical brushing with
each group sample teeth whiteness is measured for 2nd time and then the sample teeth were
submerged into the same solution with oral bacteria for 10 days. The teeth whiteness is measured
again for 3rd time and the bacteria from the surface of teeth are cultivated on agar badge for 3 days.
We have compared with average of whiteness before and after test in group and each other 3 group.
The whiteness of teeth was maintained in test group II, however in other group the whiteness
achieved through brushing was lost. Also, Group II had the smallest area of bacterial colony on agar
badge (p<0.01). It is concluded that the dentifrice including the nano-hydroxyapatite is replaced
with the organic substance in enamel resulting the increase in whiteness and the resistance to
bacterial colonization, which leads to the increase the enamel remineralization in teeth and result to
decrease in caries susceptibility.
Effect of Dehydration Methods on Mechanical Strength of Nanohydroxyapatite/Collagen Composites
Authors: Lin Xiao Yan , Li Xu Dong , Zhang Xing Dong
Published: March 2009

Hydroxyapatite/collagen composites were prepared in-situ synthesis. The composites
were finally achieved by dehydration including air-drying and freeze-drying methods. FTIR, XPS
and DSC were employed to investigate the composites dehydrated by two methods. The air-dried
composites had better mechanical properties than those of the composites dried by freeze drying.
Air-drying of the composite induced more bond formation and crosslink between collagen fibers
and HA crystals compared with freeze-drying of the composite, as indicated by the shifting of
amide A and I bands to the lower wavenumber and by the changes in the binding energy of O1s,
Ca2p, and P2p, leading to the increase of the peak temperature of the composites. Collagen
crosslink and bond formation in the air-dried composites were key factors to increase the bending
strength of the composites. The results of this study confirm that in situ synthesis and air-dry
method are effective ways to obtain nanoHA/COL composites with high mechanical properties.
Characterization of Hydroxyapatite Sputtered Films Doped with Titanium
Authors: Ribeiro A.R. , Piedade Ana P. , Ribeiro C.C. , Vieira M. Teresa , Barbosa Mario A.
Published: March 2009

In the present work, thin films of hydroxyapatite (HAp), titanium, and hydroxyapatite doped with different titanium concentrations were obtained by sputtering and characterized using several analytical techniques. These films are intended to be used as model surfaces on protein adsorption studies in order to better understand the role of titanium ions in biological processes.
Biological Efficacy of Modified Structure of Polymer Surfaces for Bone Substitute
Authors: Pan Zhi Jun , Huang Xin , Yang Di Sheng , Unuma Hidero , Yan Wei Qi
Published: March 2009

Hydroxyapatite (HA) coatings were introduced onto Poly L-lactic Acid (PLLA) polymer
in a controlled manner by immobilized urease method with a shortened precipitation time.
Osteoblastic-like cellular responses to the composite were examined in terms of cell proliferation,
differentiation and cell morphology, as well as the expression of bone-associated genes. The cells
exhibited higher cellular proliferation at 2 and 4 days on the HA/PLLA composite compared to
PLLA scaffold, while no significant difference was observed later at 6 days. The alkaline
phosphatase (ALP) activity by cells at 7 days was statistically higher on HA/PLLA scaffold than on
PLLA. Moreover, the gene expression of ALP and osteocalcin (OC) was up regulated on HA/PLLA
composite by RT-PCR analysis. The preliminary study suggested that the use of the controlled
modification of hydroxyapatite coating on PLLA scaffold to produce HA/PLLA composite might
enhance cellular activity, indicating the potential use for bone substitute in tissue engineering.
Contribution of Surface Charge to Bovine Serum Albumin Adsorption on Hydroxyapatite Ceramic Particles
Authors: Zhu Xiang Dong , Fan Hong Song , Chen X. N. , Li Dong Xiao , Zhang Xing Dong
Published: March 2009

Protein adsorption is driven by various interactions. The contribution of surface charge to
bovine serum albumin (BSA) adsorption on hydroxyapatite (HA) ceramic was investigated by
adjusting the liquid environment in which the solid particles dispersed. Zeta potentials of HA and
the adsorption of BSA on the surface were tested as a function of pH, ionic strength, Ca2+ and PO4
3-
concentrations in the aqueous solutions, and the results showed that both of them were greatly
affected by those experimental variations. Besides, the amount of adsorbed BSA was related to the
variation of zeta potential of HA, as could be well understood in terms of electrostatic interactions.
Studies on Characteristics and Adsorption of BSA on Hydrogel Biomaterials
Authors: Tan G.X. , Cui Ying De , Wang Ying Jun
Published: March 2009

Hydrogel biomaterials were synthesized by radical copolymerization of N-vinyl pyrrolidone (NVP) and 2-hydroxyethylmathacrylate (HEMA), with azobisisobutyronitrile (AIBN) as an initiator, reacting at 60~70°C for 24 hours, which were designed as contact lens due to the good chemical stability and high biocompatibility. The absorbency of bovine serum albumin (BSA) was measured by the ultraviolet spectrophotometer. The influence of pH, initial protein concentration and ionic strength were investigated in detail. The results showed that the absorption of protein on hydrogel biomaterials increased with the immersing time increasing, and was stable during 4 days. The absorption of protein on hydrogel increased with the equilibrium water content increasing. The protein absorption on hydrogels reduced the permeability of the oxygen of the biomaterials.
Preparation and Characterization of Hydroxyapatite/Bacterial Cellulose Nanocomposite Scaffolds for Bone Tissue Engineering
Authors: Jiang Hong Jiang , Wang Yu Ling , Jia Shi Ru , Huang Yuan , He Fang , Wan Yi Zao
Published: March 2009

The surfaces of BC (bacterial cellulose) nanofibers are covered with homogeneous
nano-sized precipitates upon exposure to SBF. The characteristics of the nanocompoiste scaffolds
are characterized by XRD, FTIR, TEM and SEM. It is believed that the the HAp/BC nanocomposite
scaffold are promising in applications of bone tissue engineering.
Analysis of Free-Layer Damping Coatings
Authors: Torvik Peter J.
Published: March 2009

A free layer damping treatment is formed by applying a coating of a high damping
material to one or both sides of a structure. If the coating is perfectly bonded to the structure, the
coating may be taken as being subjected to the strain at the interface between structure and coating.
Consequently, the dominant component of strain is tensile. Free layer treatments may be
symmetric (identical coatings on both sides of the structure), or asymmetric (one side only), and
applied to beams, plates or shells in bending or in tension. Two classes of treatments are of interest,
those employing thin coatings of a relative stiff damping material, and those employing thick
coatings of a relatively soft material. As many materials useful as hard coatings are nominally
linear but have inherently nonlinear damping characteristics, provision for this must be made.
Laminated Ceramic Structures within Alumina / YTZP System Obtained by Low Pressure Joining
Authors: Gurauskis Jonas , Sanchez-Herencia Antonio Javier , Baudín Carmen
Published: March 2009

The production of multilayer ceramics by laminating stacked green ceramic tapes is
one of the most attractive methods to fabricate layered materials. In this work, a new
lamination technique was employed to obtain laminated ceramic structures in the aluminazirconia
system with residual stress compression at the outer layers. This reinforcement
mechanism would lead to ceramics with changed material properties and R-curve behaviour.
The optimization of processing parameters for fabrication of defect free monolithic and
laminated structures is described. The residual stresses developed in the laminated structures
are discussed in terms of the results obtained from piezo-spectroscopic technique
measurements and finite element method calculations.
Residual Stresses in Laminar Functionally Graded Ceramic Materials
Authors: Hvizdoš Pavol , Norberg Kristoffer
Published: March 2009

A simple analytical model of residual stresses far from edges in symmetrical planar
functionally graded material (FGM) is presented. The model is based on elastic plate theory and
neglects the influence of edges and free surfaces. The results are compared to analytical model of
laminar ceramics and to finite element model of FGM. The influence of various geometrical and
material parameters on the internal stress state is discussed.
Water Based Colloidal Processing of Ceramic Laminates
Authors: Sanchez-Herencia Antonio Javier
Published: March 2009

Multilayered materials and coating are complex structures proposed among others to face the structural requirements of ceramics. The development of reinforcement mechanism by laminated structures can be due to deflection criteria or to the presence of residual stresses and requires of tailored laminates. These designs are characterized by the phases, thickness and distribution of the layers as well as the joining strength between them. In this sense water based colloidal processing techniques are used to fabricate layered structures by consolidating the layers from fluid dispersions of the powders in water. In these processing methods the phases presented in the final laminate are mainly given by the composition of the starting slurries while the changes in thickness and sharpness of the layers are controlled by acting on the processing parameters. The achievement of stable slurries is a shared step for all the colloidal processing techniques. In the water based slurries the stability will be dominated by the polar media, the surface behavior of the particles and the presence of dispersant additives to increase the repulsion between particles. The stable slurry ensures an effective milling and dispersion of the phases as well as high solid loadings, if required. Further processes associated to shaping and consolidation of the layers requires the incorporation of additives and-or water removal. The shaping methods based on aqueous slurries can be classified taking into account the process of solid-water separation. For each of those shaping methods, the nature and amount of the additives is different in order to get the optimum rheological behavior and green strength after drying. Depending on the thickness of layers and coatings as well as the shape and dimensions of the samples, the shaping method can be selected alone and combined with others.
Effects of Different Debinding Atmosphere on the Properties of Powder Injection Molded AlN Ceramics
Authors: Du Xue Li , Qin Ming Li , Humail Islam S. , Feng Pei Zhong , Qu Xuan Hui
Published: March 2009

In the present work the influence of two different thermal debinding atmosphere, vacuum and air, on the properties of 5wt% Y2O3-doped aluminum nitride (AlN) ceramics was investigated. The AlN powder as a raw material was synthesized by self-propagating high-temperature synthesis (SHS) and compact was fabricated by employing powder injection molding technique. The polymer-wax binder consists of 60wt% paraffin wax (PW), 35wt% polypropylene (PP) and 5wt% stearic acid (SA). The binder was removed through debinding process in two steps, solvent debinding followed by thermal debinding. After the removal of binder, specimens were sintered at 1850˚С in nitrogen atmosphere at atmospheric pressure. The result reveals that debinding atmosphere has significant effect on the thermal conductivity and densification of AlN ceramics. The microstructure and secondary phase identification was determined by scanning electron microscopy and X-ray diffraction. The thermal conductivity and density of injection molded AlN ceramics are 177.3W·m-1·K-1 and 3.31g·cm-3 in the air and 200.8W·m-1·K-1 and 3.28g·cm-3 in the vacuum.
Near-Net Shaping of Microwave Ceramics by Gel-Casting with Carrageenan
Authors: Liu W. , Wang Y.X. , Xiong Zhao Xian
Published: March 2009

Single carrageenan and combinations of carrageenan with other polysaccharides, including
locust bean gum and konjak gum, are applied to form green bodies of microwave ceramics by gel-casting
technique. Similar dielectric properties of the samples are achieved and compared with ceramics formed
by dry pressing method.
Preparation of PZT Slurry with High Solids Loading and Low Viscosity for Gelcasting
Authors: Zhou Dong Xiang , Yan Bo Wu , Jiang Sheng Lin , Deng Yi Hua
Published: March 2009

The dispersion and stability of PZT aqueous suspensions were investigated by using
ammonium salt of polyacrylic acid (PMAA-NH4) as the dispersant. By observing the sedimentation
behavior and measuring the viscosity, the effects of dispersant concentration and pH value on the
dispersion and stability of the suspensions were studied. The experiment results showed that the optimum
concentration of PMAA-NH4 and the optimum pH were 0.25-0.45 wt.%( by weight of the PZT powders)
and 8.5-10, respectively. When the dispersant concentration was about 0.45 wt.%, and pH value was
about 9.4, the stable PZT suspensions with high solids loading (up to 52 vol.%) and low viscosity (<1Pa.s)
was obtained for gelcasting. The microstructure of ceramic formed by gelcasting was denser and more
homogeneous than that by die pressing.
Fabrication of TiAl Intermetallic by Spark Plasma Sintering
Authors: Wu Hai Tao , Yue Yun Long , Wu Wei Bing , Yin Hai Yan
Published: March 2009

The γ-TiAl intermetallic compounds were produced at the temperature ranging from 850°C to
1050°C by the Spark Plasma Sintering (SPS) process. The effects of sintering temperature and holding
time on the mechanical properties of γ-TiAl intermetallic compounds were investigated. The γ-TiAl
intermetallic compounds sintered at 1050°C for 10 min showed a high relative density more than 98%,
and had the best three-point bending strength of 643MPa, fracture toughness of 12 MPa·m1/2 and
microhardness of 560MPa. The microstructural observations indicated typical characteristics of
intergranular fracture, which meant the poor ductility of γ-TiAl intermetallic compounds.
Processing and Properties of Highly Textured Si3N4 Materials
Authors: Belmonte Manuel , Miranzo Pilar , Osendi María Isabel
Published: March 2009

Textured Si3N4 materials have been fabricated by extruding ceramic pastes, containing
β-Si3N4 seeds, and later densification by hot-pressing. A strong anisotropy in the microstructure of the
specimens was observed, which drastically influenced their properties. The thermomechanical and
tribological behavior of the textured materials were investigated. The surface perpendicular to the Si3N4
grain alignment presented higher wear resistance than the parallel one. The thermal conductivity of the
material increased when the heat flux ran along the elongated Si3N4 grains.
Fabrication and Mechanical Properties of SiCf/SiC Composites via Polycarbosilane Pyrolysis
Authors: Wang Yi Fei , Ma Qing Song , Mu Jing Yang , Wang Jun
Published: March 2009

Continuous SiC fiber reinforced SiC composites were fabricated by PIP route and their microstructures
and mechanical properties were characterized. The density, flexural strength and fracture
toughness of the composites were 1.88 g/cm3, 307 MPa and 8.24 MPa⋅m1/2, respectively. The low
mechanical properties were ascribed to low density and strong interfacial bonding. The composites
exhibited poor oxidation and thermal shock resistance; however, they showed desirable thermal stability.
Dielectric and Mechanical Properties of Unidirectional SiC Fiber-Reinforced Aluminum Phosphates Composite
Authors: Wang Xin Peng , Tian Shi
Published: March 2009

In this paper, the unidirectional SiC fiber-reinforced aluminum phosphates composites, in
which the SiC fibers were heat-treated at different temperature, time and in different method, were
prepared. The dielectric and mechanical properties of the composites were studied. The influences of heat
treatment of SiC fiber on the properties of the SiC fiber-reinforced aluminum phosphates composite were
investigated in detail. The flexural strength, relative dielectric constant and dielectric dissipation factor of
the composite were measured. And the microstructure of the composite was characterized by SEM
(scanning electronic microscope). The results show that heat treatment of SiC fiber has a great influence
on mechanical and dielectric properties of the composite. The heat treatment decreases the dielectric
constant and dielectric dissipation factor of the composite enormously. But at the same time, the heat
treatment of the SiC fiber makes an unfavorably strongly bonded SiC fiber/aluminum phosphates matrix
interface, which decreases the strength of the composite extraordinarily. And the composite displays a
completely brittle failure behavior without fiber debonding and pulling out, which is detected by SEM.
The Influence of Precursor on the Microstructure and Characterization for Sr0.5Ba0.5Bi4Ti4O15 Thin Films
Authors: Xie Dan , Pan Wei , Ren Tian Ling , Liu Li Tian , Dang Zhi Min
Published: March 2009

The uniform Sr0.5Ba0.5Bi4Ti4O15 thin films were prepared using a modified Sol-Gel technique
and the influence of precursor on the microstructure and characterization of thin films were studied. The
stability and uniformity of precursor solution is key issue for the quality of thin films. Ethanolamine is an
effective complexation reagent of Bi3+, which could moderate the acidity of precursor. When pH value
and concentration of precursor solution was about 3.5 and 0.35M respectively, the smooth and uniform
Sr0.5Ba0.5Bi4Ti4O15 thin films could be obtained. The Bi-layered perovskite structure of
Sr0.5Ba0.5Bi4Ti4O15 formed at 750°C. The morphology of the grains in Sr0.5Ba0.5Bi4Ti4O15 thin films was
elliptoid and the grain size was about 90 ~ 100 nm.
Interformational Exfoliation of Ti3Al2 Induced by Cu
Authors: Ai Ming Xing , Zhai Hong Xiang , Tang Zhao Yun
Published: March 2009

An interformational exfoliation behavior of the layered Ti3AlC2 induced by copper was firstly
investigated via a “Cu-Ti3AlC2-Cu” sandwich sample infiltration-sintered at 1100oC to 1200oC. It was
found that the molten Cu accelerates Ti3AlC2 to decompose, induces the interformational exfoliation to
generate, and consequently forming a sub-micro-layered structure making up of TiC0.67 layers and Cu-Al
alloy layers within a Ti3AlC2 grain. This interformational exfoliation behavior can be attributed to a
topotactic mechanism due to the outward diffusion of Al the entering of Cu.
Effect of Ti3SiC2 Content on Mechanical Properties of Ti5Si3-TiC-Ti3SiC2 Composites
Authors: Qin Chao , Wang Lian Jun , Bai Sheng Qiang , Jiang Wan , Chen Li Dong
Published: March 2009

Ti5Si3-TiC-Ti3SiC2 composites containing different Ti3SiC2 volume fractions from 0 to 50% were in-situ fabricated by spark plasma sintering using Ti and SiC powders through adjusting the molar ratio of Ti to SiC. The morphologies of the fracture surfaces were analyzed by scanning electron microscopy (SEM). The room temperature mechanical properties of composites including hardness, bending strength and fracture toughness were tested.
Reaction Synthesis of TiAl-Al2O3 Composite
Authors: Zhu Jian Feng , Gao Ji Qiang , Wang Fen
Published: March 2009

Titanium aluminide composite reinforced with submicron Al2O3 has been prepared by a reactive hot press method using TiO2, Al and Ti powder as source materials. The reaction synthesis processing is particularly investigated. Results show that the matrix of the as-prepared material is a mixture of TiAl and a small amount of Ti3Al. Fine Al2O3 particles that act as reinforcing phase are dispersed along the interface of the matrix. The reduction of TiO2 involves many transitional stages, including Ti-Al reaction, TiO2-Ti reducing reaction, reaction between TiO2 and Al, etc.
Microstructure and Mechanical Properties of Heat-Resistant Silicon Carbide Ceramics
Authors: Kim Young Wook , Chun Yong Seong , Lee Sung Hee , Park Ji Yeon , Nishimura Toshiyuki , Mitomo Mamoru , Ryu Woo Seog
Published: March 2009

There has been a great progress in the development of heat-resistant silicon carbide ceramics, owing to the better understanding of composition-microstructure-properties relations. Based on the progress, it has been possible to fabricate heat-resistant SiC ceramics with improved fracture toughness. In this paper, three rare-earth oxides (Re2O3, Re=Er, Lu, and Sc) in combination with AlN were used as sintering additives for a β-SiC containing 1 vol% α-SiC seeds. The effect of intergranular phase, using Re2O3 and AlN as sintering additives, on the microstructure and mechanical properties of liquid-phasesintered, and subsequently annealed SiC ceramics were investigated. The microstructure and mechanical properties were strongly influenced by the sintering additive composition, which determines the chemistry and structure of IGP. The strength and fracture toughness of the Lu2O3-doped SiC were ∼700 MPa at 1400oC and ∼6 MPa.m1/2 at room temperature, respectively. The beneficial effect of the new additive compositions on high-temperature strength was attributed to the crystallization of the intergranular phase.
Dielectric Characterization and Microstructures of Pr6O11-Doped Bi4Ti3O12 Thin Films
Authors: Chen Min , Sun Y.H. , Su K.L. , Liu J. , Chen S. , Wan Z.M.
Published: March 2009

Pr6O11-doped bismuth titanate and random oriented BixPryTi3O12 ( y = 0.3, 0.6, 0.9, 1.2) thin films were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Pr doping into BIT caused a shift of the Curie temperature (TC) of the BIT from 675°C to 578 , 517, 398 , and 315oC for the films with y = 0.3, 0.6, 0.9, and 1.2, respectively. The experimental results indicated that Pr doping into BIT result in a remarkable improvement in dielectric properties. Raman analysis shows that Pr3+ and Pr4+ ions substitution only appears in A-sit.
Low-Temperature Sintering of 3Y-TZP/Glass Composites as All-Ceramic Dental Materials
Authors: Sun Zheng Qiu , Miao Hong Yan , Tan Guo Qiang , Xia Ao
Published: March 2009

3Y-TZP ceramics were fabricated with the addition of 10wt% MgO-Al2O3-SiO2 glass additive
by cold-isostatic pressing and afterwards liquid-phase sintering at 1200-1400°C for 2 h. The densities of
samples sintered at 1300°C for 2 h reaches 99.1%, but further increase of sintering temperature results in
the decrease of densities. XRD analysis showed that the cordierite crystals and a small amount of amorphous
phase were presented at the grain junctions, and SEM observation indicated that the mean grain
size of ZrO2 with round-shape ranged from 200 to 300 nm, which was below the critical transformation
size, and the increase in sintering temperature was accompanied with an increase in the mean grain size.
The strength and toughness of samples were kept in the range of 396-528 MPa, 4.4-5.8 MPa·m1/2 respectively,
which could meet the need of clinical applications of all-ceramic dental materials.
Electrochemically Assisted Co-Precipitation of Electrically Conducting Polymer with Calcium Phosphate Coatings on Ti Alloys
Authors: Ma Chen , Qu Li Jie , Li Mu Qin , Yang Shi Qin , Wang Jian Ping
Published: March 2009

Electrically conducting polymer containing calcium phosphate coating (ppy/brushite) was
made on the Ti-6Al-4V surface by means of electrochemically assisted co-precipitation. This study
examined the effects of the electrically conducting polymer on electrochemically assisted co-precipitation
of ppy/ brushite onto titanium alloys. Electrochemically assisted co-precipitation of ppy/ brushite coatings
resulted in an increase in the thickness and adhesion of coatings compared to those of coatings of single
calcium phosphate at the same deposition conditions. The surface morphology of coatings characterized
by SEM showed that the morphology of ppy/ brushite was superior to that of brushite. XRD indicated that
ppy did not change the phase of brushite. Thus, this electrochemically assisted co-precipitation technique
provides an effective method of polypyrrole incorporation at physiological temperature, which can offer
excellent thickness, adhesion and structure of coatings, with a potential for sustained release of
therapeutic agents as required for metallic implant fixation.