bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Analysis of the Stress Intensity Factor and the Residual Stress by Cold Expansion Method in CT Specimen
Authors: Jang Jae Soon , Kim Cheol , Cho Myoung Rae , Yang Won Ho
Published: March 2009

Cold expansion method retards the crack initiation due to the compressive residual stress
developed on a hole surface. Most previous researches have shown only the beneficial distribution
of residual stresses in the retardation of the crack initiation at the stress concentration area. Also,
there have been only few studies on the relation between crack growth and residual stress around
other adjacent holes. A few fastener holes of aircraft structures is a shot distance which is less than
20mm between holes. The purpose of this study is to provide better understanding of the residual
stress effect around a hole in a structure as crack growth starts from another hole. By finite element
method, this study showed that residual stress in a CT specimen is redistributed by cold expansion
process and that tensile stress increases in proportion to the cold expansion ratio in the vicinity of
the crack. Stress intensity factor increases as the cold expansion ratio increases.
Ultrasound Speed in Articular Cartilage under Different Bathing Saline Concentration
Authors: Zheng Y.P. , Patil S , Wang Q.
Published: March 2009

Ultrasound techniques have recently been widely used for the characterization of articular cartilage (artC) in vitro and in vivo. The sound speed in artC plays an important role either as an indicator for the artC degeneration or for the calculation of other parameters such as tissue thickness or stiffness. Previous studies on artC have been carried out in bathing saline solutions with different concentrations to investigate swelling behaviors of artC. There is a lack of information in the literature about the effect of bathing saline concentration on the sound speed of artC. In the present study we measured sound speed in artC under different saline concentrations ranging from 0M to 2.5M at the room temperature temperature (21±1°C). ArtC specimens from bovine patellar models (n=20) were used in these in-vitro studies. Results demonstrated that the sound speed in artC ranged from 1681±50 m/s to 1816±54 m/s when the saline-concentration varied from 0M to 2.5M, while the sound speed in saline changed from 1521± 3 m/s to 1674 ± 3 m/s. The sound speed linearly (r2 = 0.99, p <0.001) increased with the increase of the saline concentration at a rate of 55 m/s per mole change. It is concluded that the variations of the bathing saline concentration significantly affect the sound speed in artC and should be well documented in the ultrasonic studies of artC.
Pressure Distributions on the Buttocks and Thighs by Electrical Stimulation in the Sitting Posture
Authors: Hwang Sung Jae , Kaplan Hilton , Loeb Gerald E. , Kim Han Sung , Kim Young Ho
Published: March 2009

Pressure distributions on the buttocks and thighs by the functional electrical stimulation on
the gluteus maximus, sartorius and hamstring in the seating posture were analyzed for ten healthy
young volunteers in order to determine which muscle can be stimulated for pressure ulcer prevention.
Muscles were stimulated every 5 seconds over 30 seconds by the MP150 stimulator. Pressure
distribution and ground reaction forces on the stimulated buttocks and thighs increased when the
gluteus maximus was stimulated. Pressure on the stimulated thigh slightly decreased
when stimulating sartorius and hamstring individually. With a simultaneous stimulation of the
gluteus maximus and sartorius, pressures on the stimulated buttocks and thighs increased
significantly, but pressure on the opposite buttock decreased significantly. With a simultaneous
stimulation of the sartorius and hamstring, both pressure on the stimulated thigh and the ground
reaction force significantly decreased.
High-Velocity Impact Characteristic of Carbon Fiber Reinforced Plastic Laminates Using Ballistic Range
Authors: Hwang Do Yeon , Shimamoto Akira , Takayama Kazuyoshi
Published: March 2009

Recently, high-performance hybrid composites have been used for various applications
which require the high strength, high stiffness and low weight. There are growing needs in an
automotive, an aircraft, and military applications for composite materials since they have good
structural characteristics. They also have good penetration resistance and structural integrity after
impact. In order to clarify the mechanism of high-speed destruction for composite materials, this
study examined the penetration resistance and the fracture behavior of CFRP (Carbon Fiber
Reinforced Plastic) Laminates by using ballistic range (one-stage light gas gun). Test materials for
investigation are carbon/epoxy laminated composite materials with fiber direction; [0°]8, [0°/45°]4s,
[ 0°/90°]4s, [ 0°/45°/90°]3s and [ 0°/45°/-45°90°]2s. The high speed camera allows us to capture and
analyze the dynamic penetration phenomena of the test materials.
Buckling of Thin-Walled Cracked Columns
Authors: Carloni Christian , Gentilini Cristina , Nobile Lucio
Published: March 2009

In this paper, the problem of torsional buckling of a thin-walled edge cracked column,
under pure bending, is studied. To the authors’ knowledge, this subject has not been widely
investigated in the literature. A cracked member can buckle in the plane orthogonal to the crack and
out of plane triggering the Mode-III crack opening. Analytical expressions for the characteristic
equation are derived for an I-beam. The influence of the crack length and position on the buckling
load is investigated.
Synthetical Numerical Model for Evaluating Blade Fatigue Life of Liquid Corrosion in Steam Turbine
Authors: Xie Yong Hui , Zhang Di , Feng Zhen Ping , Sun Bi
Published: March 2009

Liquid corrosion of steam turbine blade has become an important reason for blade failure
in supercritical parameter power plant and nuclear power plant. In order to improve the reliability of
blades in wet steam stages of steam turbine and prevent blade failure from liquid corrosion, a
nonlinear coupling wave model has been developed to investigate the high speed impact between
ball liquid droplet and elastic solid, according to a mass of numerical results of impact between
liquid droplet and elastic solid made by 1Cr13 which is a typical material for steam turbine blade,
the relational expression between dimensionless equivalent peak stress and impact speed mach
number is obtained. Then suitable equations to evaluate the fatigue life of crack initiation and
nonlinear cumulative damage rule are adopted to develop numerical model for liquid corrosion
fatigue life of blade, and the liquid corrosion fatigue life of a wet steam blade is analyzed in detail.
It is shown that the nonlinear coupling wave model for impact and the analysis model of liquid
corrosion fatigue life for blade can give some quantitative results, it may be helpful to evaluate
liquid corrosion fatigue life of blade and prevent blade from liquid corrosion during blade design.
The Perfect Elastic-Viscoplastic Field at Mode I Quasi-Static Propagating Crack-Tip in Rate-Sensitive Material
Authors: Liang Wen Yan , Wang Yong Jun , Wang Zhen Qing , Lv Hong Qing
Published: March 2009

Under the assumption that the artificial viscosity coefficient at the propagating crack tip
is in inverse proportion to power law of the plastic strain rate, a rate-sensitive constitutive
relationship is derived for perfect elastic-plastic material. With the adoption of the rate-sensitive
constitutive relationship, it is asymptotically investigated the propagating tip fields of plane strain
mode I. And the quasi-static equations are obtained separately governing the stress and strain fields
at the crack-tip by means of Airy stress function. Numerical calculations of governing equations are
carried out by double parameters shooting, with selections of appropriate values of each
characteristic parameter by combinations of boundary, and the fully continuous stress-strain fields
are obtained at the crack-tip. The analytical and computational results indicate that viscosity effect
is an important factor in crack-tip fields.
Effects of Randomness of Material Parameters on Crack Failure of Concrete
Authors: Du Cheng Bin , Ren Chao Jun , Ying Zong Quan
Published: March 2009

Concrete is taken as three-phase composites consisting of aggregate, interface and mortar
matrix in the paper. The tensile strength and elastic modulus of each phase material are assumed to
obey Weibull distribution. A few random aggregate and random parameter models are generated by
Monte-Carlo method. Tensile failure of micro element is described by tension damage model, in
which the stress will be reduced linearly after the stress reaches the maximum tensile strength. The
results show that more cracks of lower homogenous specimens are observed than those of higher
homogenous specimens. The phenomenon of discontinuous cracking is observed in the former, while
strain localization and brittle behavior is observed in the latter. The ultimate load obtained in the
numerical simulation agrees well with that of the test.
Detection of Multiple Cracks in Triangular Cantilevers Based on Frequency Measurements
Authors: Wang Fei , Zhao Xue Zeng , Chen Jia Ying
Published: March 2009

Triangular cantilevers are used as small force sensors. Prediction of location and size of
multiple cracks from experimental results will be of value to users and designers of cantilever
deflection force sensors. We extend a method for prediction of location and size of multiple cracks in
rectangular cantilevers to deal with triangular cantilevers in this paper. The cracks are assumed to
introduce local flexibility change and are modeled as rotational springs. The beam is divided into a
number of segments, and each segment is associated with a damage index, which can be calculated
through the relationship between the damage index and strain energy of each segment and the
changes in the frequencies caused by the cracks. The location of cracks can be obtained with high
accuracy with sufficient segment numbers. The size of a crack can be calculated through the
relationship between the crack size and its stiffness, which can be obtained from the damage index
related to the crack. The maximum error in prediction of the crack position in the case of double
cracks is less than 15%, and it is less than 25% in prediction of the crack size.
Dynamic Anti-Plane Behavior of the Interaction Between a Crack and a Circular Cavity in a Piezoelectric Medium
Authors: Song Tian Shu , Li Hong Liang , Dong Jung Qiang
Published: March 2009

In this paper, the dynamic interaction is investigated theoretically between a crack and a
circular cavity in an infinite piezoelectric medium under time-harmonic incident anti-plane shearing.
The formulations are based on the method of complex variable and Green’s function. The resulting
dynamic stress intensity factors at the crack’s tip and dynamic stress concentration factors at the
cavity’s edge are obtained with crack-division technique. Numerical results are plotted to show how
the frequencies of incident wave, the piezoelectric characteristic parameters of the material and the
geometry of the crack and the circular cavity influence upon the dynamic stress intensity factors and
dynamic stress concentration factors.
Microstructure and Mechanical Properties of Zr(Y,Ce)O2 TZP Ceramics
Authors: Park Young Min , Yang Tae Young , Yoon Seog Young , Park Hong Chae
Published: March 2009

Tetragonal zirconia polycrystal ceramics prepared by sintering compacts of 3 mol.% Y2O3- and 12 mol.% CeO2-doped ZrO2 powders, in air at 1400o and 1500o C have been characterized in terms of microstructure and mechanical properties. With increasing 12 mol.% CeO2-doped ZrO2 content, the average grain size of sintered materials increased in the range 0.27-1.93 μm. The bend strength and indentation fracture toughness were 374-962 MPa and 6-10 MPa.m1/2 respectively, dependent on batch composition.
A Numerical Method for Predicting the Time to Surface Cracking of Corrosion Affected RC Structures
Authors: Zhou Xin Zhu , Zheng Jian Jun
Published: March 2009

Practical experience and observations suggest that corrosion affected reinforced concrete (RC) structures are more prone to cracking than other forms of structural deterioration. Concrete cracking incurs considerable costs of repairs and inconvenience to the public due to interruptions. This gives rise to the need for prediction of the time to surface cracking of concrete in order to achieve cost-effectiveness in maintaining the serviceability of RC structures. The intention of this paper is to develop a numerical method for predicting the time to surface cracking of corrosion affected RC structures. In this method, concrete with embedded reinforcing steel bars is modeled as a thick-wall cylinder. With an exponential curve modeling the energy dissipation process in concrete, the element transfer matrix is derived analytically. The time to surface cracking is then determined by solving the nonlinear problem numerically. Finally, the validity of this numerical method is verified by comparing with experimental results collected from the research literature.
Fracture Appearance Evaluation of High Performance Pipeline Steel DWTT Specimen with Delamination Cracks
Authors: Yang Zheng , Guo Wan Lin , Huo Chun Yong , Wang Yi
Published: March 2009

The delamination cracks and its effects on the fracture of pipeline steel are investigated
experimentally by using of Drop-Weight Tear Test (DWTT). The delamination cracks are produced
by the stress perpendicular to the weak interfaces before main crack beginning or accelerating, no new
delamination crack is produced during the stabile propagation of fracture. The quantity, splay degree
of delamination crack and the space between two delamination cracks are influenced by the stress
state of the crack tip at beginning or accelerating point of main crack and the length of delamination
crack is influenced by the stress state of the crack tip during the propagation of fracture. The surface of
delamination crack is cleavage fracture appearance with large cleavage facet. There is no
delamination crack on the brittle fracture surface below the brittle-to-ductile temperature or on the
brittle fracture region of mix-mode fracture surface with ductile and brittle region. The part of fracture
surfaces with delamination crack ought to be evaluated as the shear area because the delamination
cracks are produced only on the ductile fracture surface or on the ductile part of fracture surface.
Failure Mechanism of Concrete in Dynamic Loading
Authors: Yan Dong Ming , Lin Gao
Published: March 2009

Understanding the dynamic behavior of concrete in rapid loading is an issue of great importance in civil engineering. In this study, an experimental program was performed to investigate the dynamic behavior of concrete subjected to different strain-rate loadings. From the test results the rate-dependent effect on the ultimate strength of concrete was confirmed, i.e., the strength increases with the increasing strain rate. The dynamic failure process of concrete in tension and physical mechanism were discussed based on the experimental observations.
Retrofit Using Increased Section Area Method of Artificially Perforated Shear Wall in Existing Wall Dominant Structure
Authors: Choi Chang Sik , Choi Yun Cheul , Yun Hyun Do
Published: March 2009

The characteristics relating to high tensile ductility, High Performance Fiber Reinforced
Cementitious Composites (HPFRCC) are being so that studied it’ll be adopted in repair and retrofit
of buildings. A series of three shear wall specimens were tested under constant axial stress and
reversed cyclical lateral loading in order to evaluate the seismic retrofit that had been proposed for
the shear wall with the opening. The retrofit involved the use of ECC and MDF, both of which are
sprayed through the high pressure pump, over the entire face of the wall. The results indicate that
two different types of retrofitting strategies cause the different effects on the strength and ductility
of each specimen.
Elastic-Plastic Finite Element Analysis of the Effect of the Compressive Loading on the Crack Tip Plasticity
Authors: Zhang J.Z. , He Xiao Dong , Song X. , Du Shan Yi
Published: March 2009

An elastic-plastic finite element analysis of the effect of the compressive loading on
crack tip plasticity is presented. Two center-cracked panel specimens with different crack lengths
are analysed under tension-compression loading. The size and shape of the crack tip reverse plastic
zone, the crack opening profiles of the crack tip for short (0.1 mm) and long crack (2 mm) have
been studied. The analysis shows that the compressive loading has a significant contribution
towards the crack tip plasticity.
Lamination Optimization of Composite Curved Wing for Maximum Flutter Stability Using Micro Genetic Algorithm
Authors: Kim Dong Hyun , Oh Il Kwon
Published: March 2009

Flutter characteristics of composite curved wing are investigated in this study. The efficient
and robust computational system for the flutter optimization has been developed using the coupled
computational method based on the micro genetic algorithms. The present results show that the micro
genetic algorithm is very efficient in order to find optimized lay-ups for a composite curved wing
model. It is found that the flutter stability of curved wing model can be significantly increased using
composite materials with proper optimum lamination design when compared to the case of isotropic
wing model under the same weight condition.
Micromechanical Analysis of Excavation Damaged Zone in Anisotropic Rock Mass
Authors: Wang Shu Hong , Qiao Deng Pan , Jia Peng , Zhang Nan
Published: March 2009

Rock is a heterogeneous and anisotropic compound material, containing many shear
surfaces, cracks, weak surfaces and faults. Damage and failure in a rock mass can occur through
sliding along persistent discontinuities, or fractures. A new micromechanical approach to
modeling the mechanical behavior of excavation damaged or disturbed zone (EDZ) of
anisotropic rock is presented based on knowledge of the inhomogeneity of rock. In this
numerical model, damage is analyzed as a direct consequence of microcracks growth. A study
of the effect of elastic and failure anisotropy plus inhomogeneity on the underground
excavations reveals that the modes of failure can be significantly influenced by the rock
structure on the small and large scales. Fractures that develop progressively around
underground excavations can be simulated using a numerical code called RFPA (Realistic
Failure Process Analysis). This code incorporates the microscopic inhomogeneity in Young’s
modulus and strength characteristic of rock. In the numerical models of a rock mass, values of
Young’s modulus and rock strength are realized according to a Weibull distribution in which
the distribution parameters represent the level of inhomogeneity of the medium. Another
notable feature of this code is that no a priori assumptions need to be made about where and
how fracture and failure will occur – cracking can occur spontaneously and can exhibit a variety
of mechanisms when certain local stress conditions are met. These unique features have made
RFPA capable of simulating the whole fracturing process of initiation, propagation and
coalescence of fractures around excavations under a variety of loading conditions. The results
of the simulations show that the code can be used not only to produce fracturing patterns similar
to those reported in previous studies, but also to predict fracturing patterns under a variety of
loading conditions. The numerical model was able to reproduce the associated complex stress
patterns and the microseismic emission distribution for a variety of rock structural conditions.
Effects of ELID on High Speed Grinding of Partially Stabilized Zirconia
Authors: Shang Zhen Tao , Huang Han , Wang S.Q. , Sheng Xiao Min , Mi Hai Qing
Published: March 2009

Electrolytic In-process Dressing (ELID) has been applied in high speed grinding of
partially stabilized zirconia. Using a developed electrode system, the ELID effect on a bronze bond
diamond wheel was significant. This resulted in a decrease in grinding force, and thus improved the
ground surface quality. The improvement of grinding performance was attributed to the good
maintenance of wheel sharpness by ELID dressing.
Amorphous Diamond Dresser for CMP Fixed Abrasives Pad
Authors: Tso Pei Lum , Pai Yang Liang
Published: March 2009

The primary consumables in chemical mechanical polishing (CMP) are the polishing pad
and slurry. The polishing pad significantly influences the stability of the polishing process and the
cost of consumables (CoC). Usually a diamond pad conditioner is used to scrap off the polishing
debris from the pad top. Recently, an alternative planarization process can be achieved by polishing
with a "fixed abrasive pad" (FAP). In order to dress bumps on FAP, this paper use an amorphous
diamond, a diamond-like carbon deposited by cathode arc system as the dresser for FAP. The
amorphous diamond can produce a surface relief that ranges from a few nanometers to about 200
nanometers. With the addition of this dressing step on a rotary platform, FAP can renew its
polishing surface 10 to 100 times before the bumps are used up. The pad cost for polishing can be
reduced by at least ten folds and make FAP more desirable than slurry pad for silicon wafer
manufacturer due to its intrinsic capabilities to produce flatter wafers with high polishing rate.
Magnetic-Field-Assisted Finishing with Axial Vibration -Deburring on Internal Holes and Internal Finishing of Pipes with Rectangular Cross-Sections-
Authors: Fujita Hideki , Shinmura Takeo , Yamaguchi H.
Published: March 2009

In the magnetic-field-assisted finishing, grinding powder mixed with iron powder is
placed inside a part and vibration is applied to the part under magnetic field. Effects of the process
on deburring of step-wise holes and internal roughness of brass square pipes were examined.
Rotation was given to the pipes with step-wise holes, while the magnetic poles were vibrated. Axial
vibration was given to the square pipes, while the magnetic poles were fixed. Burr formed by
drilling at internal edges was effectively removed by the process. Inside roughness of the square
pipe was successfully finished to 0.023 μm Ra.
Computer Simulations of Cylindrical Plunge Grinding - Influence of Work Stiffness on Grinding Accuracy -
Authors: Horiuchi Osamu , Shibata Takayuki
Published: March 2009

This paper describes influence of work stiffness on grinding accuracy investigated by
computer simulations of grinding process for cylindrical plunge grinding. The reliability of
simulation program was demonstrated by identification with experimental results. Then, effects of
various error causes on grinding accuracy were investigated for different work stiffness. Accuracy of
the ground surface is affected in different manners by different error causes. Therefore it is not always
true that higher stiffness results in higher accuracy.
Measurement of Elastic Modulus and Residual Stress of Diamond Thin Films
Authors: Xiang Dao Hui , Chen Ming , Ma Y.P. , Sun Fang Hong
Published: March 2009

Despite great advancements in diamond thin film growth and deposition techniques,
determination of the residual stress and Young’s modulus for diamond films has continued to be a
challenge. The bulge test is a potentially powerful tool for characterizing the mechanical properties of
diamond film. In a bulge tester, pressure is applied on a thin membrane and the out-of-plane
deflection of the membrane center is measured. The Young’s Modulus and the residual stress are
simultaneously determined by using the load-deflection behavior of a membrane. By means of
electron-enhanced hot filament chemical vapor deposition (HFCVD), a diamond film was deposited
on silicon slice (100), and the free-standing window sample of diamond thin films was fabricated by
means of photolithography and anisotropic wet etching. The deflection of the membranes is measured
using a laser interferometry system. The elastic modulus and residual stress were measured using a
self-designed bulge equipment. In addition, the distortion of diamond thin films under different
pressure was simulated using finite element analysis and the contrast was made with experimental
data. The research indicated that the Young’s Modulus of diamond thin films is 937.8GPa and the
residual stress is -10.53MPa. The elastic modulus and the residual stress coincide with the report in
the literature and the value tested by X-ray diffraction, respectively. This method uses a simple
apparatus, and the fabrication of samples is very easy, and it has provided an effective means for
precise measure the mechanical properties of other thin films.
Development of a Silicon Based Air-Breathing Micro Direct Methanol Fuel Cell
Authors: Wang Li Ding , Liang Jun Sheng , Liu C. , Sun Gong Quan
Published: March 2009

As one part of the efforts to break the bottleneck of power sources in development of
integrated micro systems, a silicon based air-breathing micro direct methanol fuel cell (μDMFC)
was developed in this work. By using micro-machining technologies compatible with that in
processing of the other MEMS devices, the anode and cathode micro flow-field plates had been
successfully fabricated on a pair of 2-inch silicon wafers. The silicon μDMFC was evaluated under
ambient conditions using aqueous methanol solution with different concentrations. Results show
that open circuit potential (OCP) of the μDMFC was above to 0.6 V, and by using 3mol/L
methanol, the peak current density and power density of the silicon μDMFC could reach 28mA/cm2
and 8mW/cm2, respectively.
A Physical Machining Accuracy Predicting Model in Turning
Authors: Zhang Sheng Fang , Sha Zhi Hua , Kang Ren Ke
Published: March 2009

During the Machining process of a part, along with the generation of new surfaces, various
machining errors are produced. These machining errors depend on the characteristic of the
manufacturing process system, as there are so many undetermined factors in the process system, it is
very difficult to determine the machining accuracy of the workpiece. To the operator, the final
accuracy of the part is very ambiguous, he can only consider the shape of the workpiece, and
machining accuracy always be controlled by selecting different sets of cutting parameters. So the
machining process is always time-consuming and costly. Therefore, it is very necessary to establish
the accuracy predicting model to the workpiece. In this paper, According to the characteristic of
turning, tool nose is abstracted into a “tangential point”, “three instantaneous centers” method is
presented to get the reality shape of the workpiece. Using this method, and with the demarcating the
errors in process system, the workpiece shaping model including multi-error is established. The
model can not only describe the physical state of the workpiece, but also calculate the machining
accuracy of the workpiece conveniently. In this paper, ‘three instantaneous centers’ method is
developed to get a workpiece reality shape in turning. Using this method, the workpiece shaping
model including multi-error is established. The model can not only describe the physical state of the
work-piece, but also calculate the machining precision of the work-piece online.
Emulsified Sol-Gel Microspheres for Controlled Drug Delivery
Authors: Radin Shula , Chen T.L. , Ducheyne Paul
Published: March 2009

Controlled release silica sol-gels are room temperature processed, porous, resorbable, and
biocompatible materials. Many molecules including drugs, proteins, and growth factors can be
released from sol-gels, and the quantity and duration of the release can vary widely. Processing
parameters render these release properties exquisitely versatile [1]. The synthesis of controlled
release sol-gels involves several steps: an acid-catalyzed hydrolysis to form a sol with the molecules
included, followed by casting, aging, and drying. Additional steps such as grinding and sieving are
required to produce sol-gel granules of a desirable size. In this study, we focus on the synthesis of
controlled release sol-gel microspheres by using a novel process, which involves only two steps:sol
formation followed by emulsification. Sol-gel microspheres containing either vancomycin
(antibiotic) or bupivacaine (analgesic) were successfully synthesized via this synthesis route. Both
drugs showed controlled, load-dependent and time-dependent release from the microspheres. The in
vitro release properties of sol-gel microspheres were different from those of sol-gel granules
produced by grinding and sieving. In comparison to a fast, short-term release from the granules, the
release from the microspheres was slower and of longer duration. In addition, the degradation rate of
microspheres was significantly slower than that of the granules. These data enable the use of sol-gel
powders for controlled long-term release.
Ectopic Osteogenesis of Bone Marrow Stromal Cells Loading in Hydroxyapatite/ β-Tricalcium Phosphate
Authors: Lin Yun Feng , Wu Ling , Liu Lei , Qiao Ju , Jing Wei , Tian Wei Dong
Published: March 2009

This study was to determine the ectopic osteogenic ability of BMSCs in combination
with a scaffolding material comprising hydroxyapatite and β-tricalcium phosphate matrix
(HA/β-TCP). BMSCs were obtained from the SD rats and induced to osteogenesis. Then these
induced cells were seeded into HA/β-TCP and the constructs were auto-implanted subcutaneously
for up to 12 weeks. Histological analysis, immunostaing, RT-PCR and transmission electron
microscopy of the retrieved specimens at various intervals showed obvious trends of ectopic bone
formation with obvious alteration of cellular phenotype.
Can Basic Fibroblast Growth Factor Pre-Treatment Enhance Mesenchymal Stem Cell Therapy in Undecorticated Posterior Spinal Fusion?
Authors: Chan Chan Wai , Wong K.H.K. , Lee K.M. , Qin Ling , Yeung H.Y. , Fan H.B. , Hu Yun Yu , Cheng Jack C.Y.
Published: March 2009

Basic fibroblast growth factor (bFGF) has been shown to maintain the osteogenicity of
bone marrow derived mesenchymal stem cell (MSCs) in vitro. This study was to investigate whether
bFGF with osteogenic supplements could enhance bone formation of posterior spinal fusion. Rabbit
bone marrow derived mesenchymal stem cells were selected by adherence on plastic culture-ware.
The MSCs were exposed to dexamethasone with (bFGF group, n=6) or without bFGF (OS group,
n=6). Treated cells of two groups were seeded on β-tricalcium phosphate ceramics for one day and
then implanted onto L5 and L6 transverse processes of the same animal in posterior spinal fusion
without decortication. The ceramics acted as control (n=6). Three fluorochromes were injected
sequentially as tetracycline at week 2, xylenol orange at week 4 and calcein at week 6. The spinal
segments were harvested at week 7. The bone mineral content (BMC) and volume of transverse
processes was measured by peripheral quantitative computed tomography. The specimens were
underwent undecalcified histology. The mineralization process was examined by fluorescent
microscopy. The BMC of transverse processes in OS group was 16% greater than bFGF and control
group significantly. The volume of transverse process in OS and bFGF group was significantly
greater than control group by 54% and 46% respectively. The volume of transverse processes in OS
group was 6% greater than bFGF group though not statistically significant. In histology, newly
formed bone grew from two processes towards each other resulting in a relatively short gap distance
in OS and bFGF group while less regenerated bone was observed in the control group. At the
mineralization front, calcein which was injected into animal at week 6, was predominately labeled in
bFGF group. In OS group, both xylenol orange (at week 4) and calcein labeled were found. In
conclusion, mesenchymal stem cells pre-exposed to bFGF were not found to give additional
enhancement effect on bone formation in the posterior spinal fusion model.
Distribution of Seeded Mesenchymal Stem Cells on Hydroxyapatite Porous Ceramics
Authors: Tadokoro Mika , Kotobuki Noriko , Oshima Akira , Ohgushi Hajime
Published: March 2009

This study focused on in vivo osteogenic capability of bone marrow mesenchymal stem cells
(MSCs) seeded on ceramic scaffold. Human MSCs from a single donor were seeded on hydroxyapatite porous
ceramic (HAP) and were induced to the osteogenic lineage during in vitro culture condition, then the
MSCs/HAP composites were implanted subcutaneously into immunodeficient rats. The cellular activities of the
composites were assayed in order to evaluate the distribution and differentiation capability of seeded MSCs
before and after implantation. These results showed that the new bone, after implantation, was derived from the
donor MSCs, which adhered to the surface of the ceramics pore areas during in vitro culture. Therefore, the
engrafted donor cells proliferated and showed continuous osteogenic differentiation within the recipients.
Consequently, our study demonstrates the usefulness of MSCs/HAP composites for clinical applications.
Biotribological Properties of UHMWPE Reinforce by Nano-ZrO2 Particle
Authors: Xiong Dang Sheng , Yuan Nan
Published: March 2009

Wear is the primary cause of failure of joint replacement prostheses. In this paper, the
Ultra High Molecular Weight Polyethylene (UHMWPE) as an artificial joint acetabular material
was reinforce by nano-ZrO2 particles. The friction and wear properties of ZrO2 - UHMWPE
composites sliding against the Co-Cr-Mo alloy were studied under lubrication of distilled water,
saline and calf serum. The worn surface is observed by the optics microscope to examine the wear
mechanism of the composite. The hardness and wetting angle of the composites were also measured.
The result shows that the hardness, wettability, friction and wear resistance were all improved by
filing with nano-ZrO2 particles. The 2%ZrO2 - UHMWPE composite had the lowest wear rate.
Electrohydrodynamic Processing Routes for Bioceramics
Authors: Zhang H. B. , Edirisinghe Mohan J. , Huang Jie
Published: March 2009

Bioceramic fibres, scaffolds and mats are important structures in biomedical applications. Electrohydrodynamic routes are relatively new for processing advanced materials and in this paper we use electrospinning to prepare zirconia fibres diameter down to 200nm and hydroxyapatite (HA) fibres down to 1$m. Zirconia-polymer and nHA-polymer composite scaffolds structures (mats) with 400-1000 $m windows were also prepared.
Proteomics Study of the Osteoblast Cells Proliferated on Nanostructured Hydroxyapatite Coatings
Authors: Li H. , Khor Khiam Aik , Chen W.N. , Tan T.L. , Pan H. , Cheang P.
Published: March 2009

A big variety of bioceramics have been successfully utilized as implant materials for
promoting fixation of bony tissues. Different bioceramics exhibited markedly different proliferation
rates of the osteoblast cells in vitro. Clarification of the mechanism about the attachment and
proliferation/differentiation of the cells would contribute to selecting suitable biomaterials for hard
tissue replacement. Proteomics study was performed in this study employing the 2-dimensional
electrophoresis assay with an aim of recognizing the changes in proteins. Nanostructured
hydroxyapatite (HA) coatings have been fabricated and they have shown promising mechanical
performances. Results showed that the nanostructured HA coatings promoted proliferation of the
osteoblast cells. Alkaline phosphatase (ALP) assay revealed an increased ALP activity of the
proliferated viable cells, and obviously the presence of the nanosized pores can enhance the
anchoring and stretching of the cells. No obvious difference in the 2-D gel maps taken for the cells
proliferated on the HA coating and for control can be found. This in turn suggests that the
nanostructured HA coating induces minor changes in proteins of the cells.
Development of Bioactive Polyethylene-Apatite Nuclei Composite
Authors: Yabutsuka Takeshi , Yamaguchi Seiji , Hibino Mitsuhiro , Yao Takeshi
Published: March 2009

Apatite nuclei were precipitated in the pores of the porous polyethylene matrix in 2.0SBF. Apatite was induced by the apatite nuclei inside the pores and on the surface of the composite and grew to the surface of the composite by a soak in 1.0SBF. The formed apatite showed high adhesive strength to the composite probably due to a mechanical interlocking effect between the matrix and the apatite.
Bone-Like Apatite Formation on Modified PCL Surfaces under Different Conditions
Authors: Wang Ying Jun , Yang Chun Rong , Zheng Hua De , Chen Xiao Feng , Ning Cheng Yun , Ren Li , Deng Chun Lin
Published: March 2009

The PCL plates hydrolyzed by NaOH aqueous solutions and carboxylate groups were
introduced onto the surfaces of specimen. Specimens were treated by CaCl2 and K2HPO4⋅3H2O under
the normal-pressure condition and low-pressure of 103 Pa condition for 30min separately. Dense and
uniform bone-like layers could be formed on the surface of specimens after mineralizing for less than
24h in simulated body fluids (SBF). The low-pressure condition could accelerate the formation of
apatite layer.
Biomineralization of Electrospun Nano-HA/PHB GTR Membrane
Authors: Guan Dong Hua , Huang Chun Peng , Liu Ji , Tian Kun , Niu Lin , Lin Ying He , Qu Yi Li , Wang Peng , Ye Yong Mei , Chen Zhi Qing
Published: March 2009

Poly 3-hydroxybutyrate (PHB) as a kind of polysaccharides has been proved promising for tissue engineering because of its biocompatibility and biodegradability. But its poor mechanical properties and hydrophilicity limit its application. In order to explore a new useful porch to improve the performance of PHB-based GTR membrane, membrane composed of nano-HA / PHB composite was manufactured through the air/jet electrospinning process which can potentially generate nanometer scale diameter fibers and enlarge surface area of materials while maintaining high porosity. Successively, the biomineralization behavior of the membrane in supersaturated calcification solution (SCS) was studied. The Results of this investigation show that the successfully manufactured porous nano-HA/PHB membrane has high activity in SCS and its ability of inducing the formation of mineral crystal in vitro than that of the unfilled PHB membrane. It can be concluded that the addition of nano-HA and the novel technology could improve the performance of the PHB-based GTR membrane.
The New Art of Bone Graft Substitute Design
Authors: Klinkenberg Ernst Dieter , Neumann Hans Georg , Bulnheim Ulrike , Rychly Joachim
Published: March 2009

A new method of design and manufacturing of bone graft substitutes is introduced. For
the first time it is possible to prepare bone graft substitutes with a directed and controlled pore
structure. Furthermore, the formation of sophisticated geometries is feasible. First in vitro
investigations with cell cultures show a vital cell growing on the synthetic bone graft material.
Numerous applications are possible.
Fabrication and Properties of Nano-Al(OH)3/Mg(OH)2/Micro-Capsulated APP/PP Flame Retardant Composites
Authors: Cui Yi Hua , Geng Yan , Tao Jie , Wo Ding Zhu
Published: March 2009

To improve the flame retardant performance of polypropylene (PP), three composites systems,
nano-Al(OH)3/Mg(OH)2/PP, micro-capsulated ammonium polyphosphate (MCAPP)/PP, and
nano-Al(OH)3/Mg(OH)2/MCAPP/PP had been developed and studied in this paper. Their flame
retardant and mechanical properties were measured and analyzed. The results indicated that there existed
synergistic effect of flame retardant among nano-Al(OH)3, nano-Mg(OH)2, and MCAPP. PP composites
with the three flame retardants of 3 wt%, 9 wt%, 8 wt% respectively possessed the best integrated
properties with OI value of 26.2 and little decrease in mechanical properties.
Liquid Phase Sintering Behavior of Amorphous Nano-Sized Silicon Nitride Powders
Authors: Li H.B. , Luo Jun Ting , Zhang Kai Feng
Published: March 2009

The amorphous nano-sized silicon nitride powders were sintered by liquid phase sintering method. Si3N4-Si2N2O composites were in-situ fabricated. The Si2N2O phase was generated by an in-situ reaction 2Si3N4(s)+1.5O2(g)=3Si2N2O(s)+N2(g). The content of Si2N2O phase up to 60% was obtained at a sintering temperature of 1650°C and reduced when the sintering temperature increased or decreased, which indicates that the reaction is reversible. The mass loss, relative density and average grain size increase with increasing of sintering temperature. The average grain size is less than 500nm when the sintering temperature is below 1700°C. During the sintering procedure, there is a complex crystallization and phase transition: amorphous Si3N4 → equiaxial α-Si3N4→ equiaxial β-Si3N4 → rod-likeSi2N2O → needle-like β-Si3N4. Small round-shaped β-Si3N4 particles are entrapped in the Si2N2O grains and a high density of staking faults are situated in the middle of Si2N2O grains at a sintering temperature of 1650°C.
Synthesis of a Novel B3CN3 Compound by Pyrolysis of Precursor
Authors: Yang Jian , Qiu Tai , Shen Chun Ying
Published: March 2009

An organic precursor was synthesized with C3N6H6 and H3BO3 as raw materials in aqueous solution. A novel amorphous BCN compound was obtained by thermolysis of the precursor at 1900°C in flowing N2 atmosphere. Single crystal X-ray diffraction analysis reveals that the precursor is a supramolecular compound with a formula C3N6H6(H3BO3)2. The pyrolysis product was characterized by XRD, XPS, FTIR, and SEM. XRD results reveal that the pyrolysis product has a turbostratic graphite structure. XPS analysis confirms the formation of nitrogen-rich BCN ternary compound with an approximate composition of B3CN3. Both the deconvoluted XPS spectra and FTIR spectrum indicate that B-N, B-C, and C-N chemical bonds have been established and there is no phase separation of graphite and h-BN occurred, which suggests an atomic-level hybrid of B, C, and N in the compound. SEM images show that the crystal shape of the B3CN3 compound is columnar, which is similar to the precursor.
Microstructure and Properties of Carbon-Ceramic Composite Prepared by Hot-Pressing Sintering
Authors: Qiao Ying Jie , Zhang He Xin , Zhang Xiao Hong , Hong Chang Qing
Published: March 2009

The recrystallized carbon-ceramic composites were prepared from calcined coke, coal-tar pitch
and Cr by hot-press to investigate the effects of Cr on the physical properties, mechanical properties and
microstructure of recrystallized graphite. Experimental results showed that Cr doped recrystallized
graphites exhibited higher bending strength and compressive strength and lower electrical resistivity
when the Cr content is10wt% compared with pure graphite. Microstructural analyses revealed that the
degree of graphitization of recrystallized graphite increased and the layers spacing of microcrystalline
decreased with increasing the Cr concentration. XRD analysis indicated that Cr added to the carbon
substrate was in the form of C, Cr2C3 and Cr2O3. The catalytic mechanism of Cr dopant to accelerate the
graphitization of carbon substrates can be explained by the mechanism of decomposition of the carbide.
Texture Development in Na1/2Bi1/2TiO3-BaTiO3 Ceramics by Reactive-Templated Grain Growth
Authors: Yan Yong Ke , Zhou He Ping , Zhao Wei , Liu Dan , Liu Shan Shan
Published: March 2009

High <001>-textured Na1/2Bi1/2TiO3-BaTiO3 (6mol%BaTiO3) ceramics were fabricated by
reactive-templated grain growth (RTGG), using plate-like Bi4Ti3O14 particles prepared by a molten
salt method as the templates. The effect of template concentration on the texture development and
microstructure evolution was studied, and the mechanisms of grain orientation and densification were
also discussed. The design of Bi element reaction has important impact on the texture development.
Preparation of ZnSe by CVD with the Solid Starting Materials
Authors: Fang Zhen Yi , Pan Wei , Zhu Hai Feng , Zhang Li Qiang , Fang Ming Hao
Published: March 2009

In this paper, particular CVD processes of so-called Se method with solid substances as starting
materials was investigated to fabricate ZnSe. On the basis of detailed experimental researches, the growth
model and dominant regime of deposition rate were discussed. ZnSe of high optical properties was
produced under optimized process conditions. The grain size of CVD ZnSe by Se method is less than
10μm, and its average transmittance in the wavelength range of 0.55~20μm is up to 70%.
The Preparation of Fibrous MCM-41 Using Microwave Heating
Authors: Park Seong Soo , Park Ji Hwan , Park Jeong Hwan , Hong Seong Soo , Park Hong Chae , Lee Gun Dae
Published: March 2009

Mesoporous MCM-41 materials were prepared using the conventional thermal and microwave
heating method. Both in conventional thermal and microwave heating synthesis of MCM-41, tetraethyl
orthosilicate (TEOS) and cetyltrimethyl ammonium bromide (CTAB) were used as Si source and template,
respectively. Microwave heating was carried out in a modified 400 W, 2.45 GHz microwave oven.
In both methods, the crystallization temperatures was 70 °C and crystallization time was 3~12 h. The
prepared MCM-41 samples were characterized by XRD, TEM and SEM. The XRD patterns of MCM-41
samples prepared from both the methods were typical of a relatively well ordered material. TEM results
also revealed that the MCM-41 samples prepared from both the methods possess the regular hexagonal
array of mesoporous channels. On the contrary, SEM has shown the difference in morphologies of the
MCM-41 samples prepared from both the methods. The samples prepared by conventional thermal
heating method mainly consist of irregular and small particles, whereas the samples prepared by microwave
heating method have elongated rope-like structure and their length extends longer than 10 μm.
Preparation of Warm Compacted and Sintered WC/Carbon Steel Composite and its Wear-Resistance
Authors: Cheng Xiao Le , Gao Yi Min , Xing Jian Dong , Yang Jian , Bao Chong Gao
Published: March 2009

The WC particulates (0.076mm~0.100mm in size) and carbon steel (0.45wt% C) are selected
as a reinforced phase and matrix in the composites. The techniques of warm compaction are
systematically investigated with powder metallurgy solid phase sintering method. The performance of
sliding friction wear of the composites is tested on a pin on disk tester. The test results of warm
compaction show that the composites sample containing 50% WC and 50% steel possesses the perfect
compaction density (9.4362g/cm3) and the relative density reaches 91.6% under the condition of 140°C
compaction temperature, 320KN stress, and lubricated with zinc stearate. The results of wear test show
that the composite sample under the condition of warm compaction gains the best wear property, and the
relative wear resistance is the 2.9 times of 15Cr cast iron, 2.6 times of 20Cr cast iron and 2.8 times of the
composite sample under the condition of room temperature compaction. And the wear mechanism of the
particle-reinforced composites is analyzed using SEM.
Synthesis and Properties of (Bi0.5Na0.5)TiO3 Powders by Hydrothermal Method
Authors: Hao Jun Jie , Wang Xiao Hui , Lin Shi Yun , Li Long Tu
Published: March 2009

Na0.5Bi0.5TiO3 (NBT) is considered to be an excellent candidate for lead-free piezoelectric
ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT
powder at relatively low treatment-temperature. The particle size and morphology of the synthesized
powders were examined by SEM. The powders were further pressed into disk and sintered at 1120°C/2h
in air, and its properties and microstructure were compared with traditionally prepared samples.