bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum Dots by QED
Authors: Prevenslik Thomas
Published: March 2009

High quantum dot (QD) efficiency may be explained by excitons generated in the quantum
electrodynamics (QED) confinement of electromagnetic (EM) radiation during the absorption of the
laser radiation. There is general agreement that by the Mie theory laser photons are fully absorbed by
QDs smaller than the laser wavelength. But how the absorbed laser photons are conserved by a QD is
another matter. Classically, absorbed laser radiation is treated as heat that in a body having specific
heat is conserved by an increase in temperature. However, the specific heats of QDs vanish at
frequencies in the near infrared (NIR) and higher, and therefore an increase in temperature cannot
conserve the absorbed laser photons. Instead by QED, the laser photon energy is first suppressed
because the photon frequency is lower than the EM confinement frequency imposed by the QD
geometry. To conserve the loss of suppressed EM energy, an equivalent gain must occur. But the only
EM energy allowed in a QED confinement has a frequency equal to or greater than its EM resonance,
and therefore the laser photons are then up-converted to the QD confinement frequency - the process
called cavity QED induced EM radiation. High QD efficiency is the consequence of multiple excitons
generated in proportion to very high QED induced Planck energy because at the nanoscale the EM
confinement frequencies range from the vacuum ultraviolet (VUV) to soft x-rays (SXRs). Extensions
of QED induced EM radiation are made to surface enhanced Raman spectroscopy (SERS) and light
emission from porous silicon (PS).
Growth of GaN Nano-Column on Si (111) Substrate Using Au+Ga Alloy Seeding by Pulsed Flow Method Using MOCVD
Authors: Song Jae Chul , Kang D.H. , Lee Seon Ho , Jang Eun Su , Kim Dong Wook , Santhakumar Kannappan , Lee Cheul Ro
Published: March 2009

Vertical GaN nano-columns arrays were grown on Au-coated silicon (111) substrate by Au+Ga alloy seeding method and pulsed flow of Gallium and ammonia using metalorganic chemical vapor deposition (MOCVD). A gold thin film was deposited on Si using an ion coating system. The Au coated Si substrate was annealed at 800 oC under hydrogen ambient for 5 min. The pre-deposition of gallium and nitrogen was performed for 60 sec to form Au+Ga and nitrogen solid solution, which acts as the initial nucleation islands. Then Gallium and ammonia were let in pulse method. Scanning electron microscopy (SEM) image reveals a vertical growth and cylindrical in shape GaN nano-column. From the sharp PL peak intensity it is clearly seen that the dislocation density is reduced considerably and the optical quality of the nano-column is improved.
Nanometer-Scale In0.5Ga0.5As Ring-Like Structure Grown by Droplet Epitaxy
Authors: Pankaow N. , Panyakeow S. , Ratanathammaphan S.
Published: March 2009

We have demonstrated the fabrication of InGaAs ring-like nanostructures by dropletepitaxy technique using molecular-beam epitaxy. Dependence on the substrate temperature and the amount of indium and gallium of the nanostructural properties was investigated. It was found that increasing substrate temperature resulted in larger InGaAs ring size but with lower density and that increasing In0.5Ga0.5 amount resulted in larger InGaAs ring size but with oscillating density. Photoluminescence results confirmed the high quality of the nanocrystal.
Luminescence Properties of ZnS:Mn Quantum Dots
Authors: Zhang Xiao Song , Li Lan , Dong Dong Qing , Wang Zhi , Dong Xiao Yi
Published: March 2009

ZnS:Mn quantum dots were prepared in the aqueous medium from readily available precursors. The construction, morphology and luminescence properties of the ZnS:Mn quantum dots were evaluated by XRD,TEM and photoluminescence spectra. The blue and orange emission of the ZnS:Mn quantum dots excited by a 532nm picosecond laser were discussed.
Broadband Emission in InAs/InGaAlAs Quantum-Dash-in-Well Laser
Authors: Ooi Boon S. , Djie Hery S. , Helmy Amr.S. , Hwang James C.M.
Published: March 2009

We report on the development of wide gain InAs/InGaAlAs/InP quantum-dash structure
for broadband diode laser and amplifier. Characterizations of this material system have been
performed using spectroscopy and microscopy techniques. Gain-guided broad area laser fabricated
using this material system exhibits lasing wavelength coverage of up to 76 nm at ~1.64 (m center
wavelength from simultaneous multiple confined states lasing at room temperature.
Nano-Scale Bandgap Engineering Using Nitrogen Implantation: Quantum-Well, Quantum-Dash and Quantum-Dot Nanostructures
Authors: Ding Y.H. , Hongpinyo V. , Djie Hery S. , Ooi Boon S.
Published: March 2009

Nano-scale spatial wavelength engineering of quantum nanostructures using nitrogen
ion-implantation induced intermixing has been developed for tuning the bandgap of quantum-well,
quantum-dash-in-well, and quantum-dot nanostructures. High performance bandgap-tuned
quantum-well and quantum-dash lasers fabricated using this technique has been demonstrated.
Investigation of Morphology and Photoluminescence of Hydrothermally-Grown ZnO Nanorods Grown on Substrates Pre-Coated with ZnO Nanoparticles
Authors: Tay C.B. , Chua Soo Jin
Published: March 2009

We show that the rod-like morphology of hydrothermally-grown ZnO nanorods can be
obtained on any substrate, pre-coated with ZnO nanoparticles, when pH<7.3 or pH>10.1. When
pH>10.1, three types of morphology, from uniform nanorods to large clustered rods, can be
distinguished based on the solubility of zinc. In line with classical thermodynamics, the density of
nanorods increases when the solubility of zinc decreases. We also report that the orange defect peak
photoluminescence can be reduced, while the UV peak increased by decreasing the pH of the growth
solution.
Modulation of Three Dimensional Photonic Band Gap in Visible Region
Authors: Liu Y.P. , Guo Y.P. , Yan Z.J. , Huang C.M. , Wang Y.Y.
Published: March 2009

Three dimensional (3D) SiO2 photonic crystals films were fabricated on quartz substrate by vertical deposition method. The effects of various preparation parameters on optical properties were studied by optical transmission measurements. Bragg reflection on parallel sets of (111) planes were observed in all the samples. The center wavelength of [111] photonic band gap (PBG) varied from 450 nm to 680 nm with the increasing sphere size. For a given sphere size, the (111) Bragg reflection of as-deposited sample shifted towards lower wavelengths as the sintering temperature T increased. The role of evaporation temperature on the optical properties of the film was also investigated. The PBG can be correspondingly modulated in visible region by changing various preparation parameters.
Structural Investigation of Cubic-Phase InN on GaAs (001) Grown by MBE under In- and N-Rich Growth Conditions
Authors: Kuntharin S. , Sanorpim S. , Nakamura T. , Katayama R. , Onabe Kentaro
Published: March 2009

We have investigated effect of the In- and N-rich growth conditions on the structural
modification of cubic-phase InN (c-InN) films grown on GaAs (001) substrates by rf-plasmaassisted
molecular beam epitaxy (RF-MBE). High resolution x-ray diffraction (HRXRD) and
Raman scattering measurements were performed to examine the hexagonal phase generation in the
c-InN grown films. It is evident that higher crystal quality c-InN films with higher cubic phase
purity (~82%) were achieved under the In-rich growth condition. On the other hand, for the N-rich
growth condition, the c-InN films exhibited higher incorporation of hexagonal phase, which is
generated in the cubic phase through the incidental stacking faults on the c-InN (111) planes. Our
results demonstrate that the In-rich growth condition plays a critical role in the growth of high
quality c-InN films with higher cubic phase purity.
Quantum Information Processing in Photonic Crystals
Authors: Singh Mahi R.
Published: March 2009

We have studied the quantum information processing phenomenon in photonic crystals doped with four-level nanoparticles. This phenomenon occurs due to the switching mechanism in the system. We consider that one of the transition energies of nanoparticles is coupled near resonantly with a photonic band gap edge. The dipole-dipole interaction between the nanoparticles has also been included. It is found that the system switches between the transparent and nontransparent states due to the dipole-dipole interaction and the band edge coupling. This is an interesting finding and can be used to produce logical photon switches in the quantum information processing.
Phase Transition in Photonic Crystals Doped with Nanoparticles
Authors: Singh Mahi R.
Published: March 2009

We have study the phenomenon on of phase transition in photonic band gap (PBG) materials doped with four-level nanoparticles in the presence of the dipole-dipole interaction. Numerical simulations for the real susceptibility have been performed for an isotropic PBG material. It is found that the real susceptibility has a singularity for a certain value of the nanostructure concentration. This is a signature of the phase transition in the system.
InGaAsP/InP Electroabsorption Modulator with Single-Sided Large Optical Cavity by Low-Pressure MOCVD
Authors: Yang H. , Chin M.K. , Lim Desmond C.S. , Lee S.Y. , Lee C.W. , Zhu H.L.
Published: March 2009

An InGaAsP/InP Electroabsorption Modulator (EAM) with single-sided large optical cavity (LOC) was studied and fabricated by low-pressure Metal Organic Chemical Vapor Deposition (MOCVD). Results show that the optical profile of EAM is greatly improved by the LOC structure, which is expected to increase the coupling efficiency and the optical saturation power.
Sputtered SiO2 Induced Atomic Interdiffusion in Semiconductor Nano Heterostructures
Authors: Hongpinyo V. , Ding Y.H. , Anderson J. , Djie Hery S. , Ooi Boon S. , Du R.R. , Ganjoo A. , Jain H.
Published: March 2009

We investigate the influence of sputtered silica as annealing cap on the enhancement of
intermixing rate of semiconductor quantum nanostructures. After sputtered silica application and
subsequent rapid thermal annealing, we observed bandgap shift of over 200 meV with respect to the
bandgap of as-grown material from various GaAs-based quantum well (QW) heterostructures such
as GaAs/AlGaAs, InAlGaP/GaAs, and GaAs/AlGaAs systems at significantly lower temperature
than the conventional dielectric cap process with plasma enhanced chemical vapor deposition
(PECVD). The results suggest that the sputtered silica process is a promising intermixing technique
for the monolithic integration of multiple active/passive photonic components on GaAs-based
material systems.
Temperature-Controlled Catalytic Growth and Photoluminescence Properties of ZnO Nanostructures
Authors: Huy P.T. , An T.T. , Chien N.D. , Kim Do Jin
Published: March 2009

ZnO nanostructures with different morphologies of nanorods, nanoneedles, nanowires,
and nanobelts have been synthesized by thermal evaporation of pure ZnO micropowder. Based on
the appearance of the as-synthesized products observed by field emission scanning electron
microscope (FE-SEM), we show that substrate temperature and catalyst are the critical factors for
the formation of different morphologies of ZnO nanostructures. The photoluminescence (PL)
properties of the ZnO nanostructures were investigated. The difference in PL spectra both in
intensity and structure for the different ZnO nanostructures are presented. We demonstrate that
under appropriate synthesis conditions, highly crystallized and defect-free ZnO nano-structures can
be obtained.
Evaluating Multi-Delamination of Composite Laminates Using an Active Sensor Network
Authors: Su Zhong Qing , Cheng Li , Wang Xiao Ming , Ye Lin , Chen Zhi Ping
Published: March 2009

A quantitative evaluation approach for multi-delamination in fibre-reinforced composite
laminates was developed, in virtue of a built-in active sensor network. The approach, conducted
hierarchically by activating different sensors in a sensor network, fused time-of-flight (ToF) extracted
from signals at different levels, whereby to provide an overall consensus as to all possible instance(s)
of damage in the laminates. Benefiting from the network, the dependence of evaluation on a specific
sensor or signal was furthest minimised, and the need for interpreting complex signal involving
scattering by multi-damage was avoided. The approach was validated by assessing the locations and
shapes of dual-delamination in a CF/EP woven laminate.
Tough Hypereutectic High Chromium White Iron – A Double In Situ Fibrous Composite
Authors: Powell Graham L.F. , Brown Ian H. , Nelson Grant D.
Published: March 2009

A tough hypereutectic high chromium white iron has been developed by considering the
alloy as a double in-situ fibrous composite and applying the principles of composite theory. The
eutectic in the ternary Fe-Cr-C system solidifies as M7C3 carbide rods of irregular hexagonal cross
section in a matrix of austenite. The carbide rods are intermittently joined together with no
misorientation at the joint. The colonies (eutectic grains) of a 27%Cr alloy solidify with a flat solid
– liquid interface. In hypereutectic high chromium white irons the primary carbide solidifies as
single crystal rods with no branching. Depending on the thermal conditions in the mould the
primary carbides are nucleated only on the mould surface, or repeatedly at the solid – liquid
interface. In 27% Cr, 4.5%C hypereutectic alloys, the as-solidified microstructure is one of long
parallel aligned primary carbides in a eutectic matrix of carbide rods in austenite, or short randomly
orientated primary carbides in a eutectic matrix. In either case the microstructure can be described
as a double in-situ fibrous composite. The application of composite theory has resulted in
hypereutectic high chromium white iron castings with improved fracture toughness similar to that
of heat-treated alloy steel but with superior wear resistance.
Microstructural Analysis on Ti-6Al-4V and 10 Vol.% (TiB+TiC)/Ti-6Al-4V Metal Matrix Composites
Authors: Mak Jonathon , Wuhrer Richard , Heness Greg , Qin J. , Lu W. , Zhang D. , Yeung Wing Yiu
Published: March 2009

Particulate reinforced Ti based metal matrix composites (MMCs) were made by in-situ
synthesis using vacuum arc re-melting process. The microstructure of the Ti-6Al-4V base alloy and
10 vol.% (TiB+TiC)/Ti-6Al-4V metal matrix composites was examined. The particulate
reinforcements were analysed and identified TiB and TiC particles. The particle distribution was
analysed using the quadrat method over 1620 quadrats. A homogeneous particle distribution was
found to establish in the composites. The experimental distribution of the reinforcements agreed
well with the theoretical Poisson distribution. A skew factor, which characterizes the degree of
asymmetry of a statistical distribution, of 1.108 was determined for the particle distribution in the
material.
Laminated Plate Elements Based on Higher-Order Shear Deformation Theories
Authors: Zhang Yi Xia , Yang Chun Hui
Published: March 2009

Efficient and accurate finite elements are crucial for finite element analysis to provide
adequate prediction of the structural behavior. A large amount of laminated plate elements have
been developed for finite element analysis of laminated composite plates based on the various
lamination theories. A recent and complete review of the laminated finite elements based on the
higher-order shear deformation theories, including the global higher-order theories, zig-zag theories
and the global-local higher-order theories is presented in this paper. Finally some points on the
development of the laminated plate elements are summarized.
Shape Control in Composite Laminates Using Piezoelectric Actuators considering Thermal Deformation
Authors: Bai Ruixiang , Chen Hao Ran , Wang Qing , Yan Cheng
Published: March 2009

Based on the first order shear deformation plate theory, a numerical analysis model of
composite laminated plates with distributed PZT actuators under thermal load was established, and
the corresponding formulae of finite element method were presented considering the effect of
adhesive layer between PZT actuator and plate. For a two ends simply supported plate, the thermal
deformation of the plates induced by different temperatures on the upper and lower surfaces and the
thermal deformation compensation for the plates using PZT actuators were studied, then the
optimization of voltages applied to each actuator was discussed.
Effect of Processing Method on Conductivity and Mechanical Properties of Glass Fibre Reinforced Carbon Black Filled Polyethylene
Authors: Yuan Qiang , Wu Dong Yang , Bateman Stuart , Shen Shirley Zhiqi , Gloria-Esparza C. , Xia Kenong
Published: March 2009

The conductivity and mechanical properties of carbon black (CB) filled polyethylene (PE)
composites depend on the conductive filler, molecular structure of polymer matrix, and the
processing methods which are applied. CB filled high density polyethylene without and with glass
fibre (GF) composites have been manufactured using single and twin screws extruder. The
composite made from the single screw extruder showed a much higher conductivity than that made
from twin screws extruder for CB/PE composites with and without glass fibre. The conductive
paths are formed at very low CB content (1wt% CB for GF/CB/PE) when using single screw
extruder to manufacture. The microstructure of these composites were analysed using SEM.
Simulations of Delamination Propagation in Composite Laminates under Static and Low-Velocity Impact Transverse Loads Using a New Cohesive Model
Authors: Hu Ning , Zemba Yutaka , Fukunaga Hisao
Published: March 2009

In this paper, we have proposed a new cohesive model to stably and accurately simulate
delamination propagations in composite laminates under transverse loads. In this model, we set up a
pre-softening zone in front of the original softening zone. In this pre-softening zone, the initial
stiffness is gradually reduced as the interface strength decreases. However, the onset displacement for
starting the real softening process is not changed in this model. The fracture toughness of materials
for determining the final displacement of complete decohesion is not changed too. This cohesive
model is implemented in the explicit time integration scheme. A DCB problem is employed to
analyze the characteristics of the present cohesive model. Moreover, an experimental example of
laminates under impact loads is employed to illustrate the validity of the present method.
Effect of Vibrations on Void Content in Composite Materials
Authors: Muric-Nesic Jelena , Stachurski Z. , Compston Paul , Noble N.
Published: March 2009

Eliminating common defects such as voids, bubbles and poor adhesion at interfaces will
increase the quality of laminated sandwich composite structure. We are experimenting and
analyzing the effect of mechanical vibrations applied to the curing system of composite materials
production, particularly on minimizing void content. The range of frequency of vibrations covered
was from 2Hz to 8kHz, for different period of vibrations. The composite laminates were made by
hand lay-up using glass fibres and vinyl-ester resin, and examined under a microscope to determine
types and quantity of defects. The results showed reduction in the number of bubbles (as well as in
void content) at frequencies between 10Hz and 50Hz for 30 minutes of vibrations.
A Knowledge-Based System for Temperature Prediction in Hot Strip Mills
Authors: Xie Hai Bo , Jiang Zheng Yi , Wei Dong Bin , Liu Xianghua , Wang Guo Dong
Published: March 2009

Rolling temperature is an important factor affecting mechanical properties of hot rolled
strip significantly. Traditional techniques cannot meet higher precision control imperatives. In the
present work, a novel knowledge-based system has been developed for the temperature prediction
in hot strip mills. Neural network has been used for this purpose, which is an intelligent technique
that can solve nonlinear problem of temperature control by learning from the samples. Furthermore,
an annealing robust learning algorithm was presented to adjust the hidden node parameters as well
as the weights of the adaptive neural networks. Simulations in a multi-object mode have been
carried out to verify the effectivity of new neural optimization system. Calculation results confirm
the feasibility of this approach and show a good agreement with experimental values obtained from
a steel plant.
Surface Roughness and Wear of Work Roll Containing Ti in Cold Strip Rolling
Authors: Li H.C. , Jiang Zheng Yi , Tieu A. Kiet , Sun Wei Hua , Li Hei Jie , Wei Dong Bin
Published: March 2009

The consumption of work rolls in cold strip mills is significant. One of the key issues for
work rolls is the surface roughness which affects the rolling stability and surface finish of the strip.
The produced strip has lower surface finish if the roll surface roughness is large. However, if the
roll surface roughness is small, it is not helpful for establishing the rolling process, which will
reduce the productivity. In this case, a laser treatment is employed to increase the value of roll
surface roughness. In order to reduce the times of roll grinding, the cold strip mill and roll
manufacturers have developed new types of rolls such as the rolls containing Ti to increase the roll
wear resistance in cold strip rolling. Results show that the new 4CrTi roll has a significant
advantage of preventing decrease of the roll surface roughness. The size and generation of particles
during roll wear process and the effect of Ti on roll wear have been discussed.
Gate Location and its Effects on Product Quality in Injection Moulding
Authors: Haddad Header , Masood Syed H. , Saifullah Abul B.M.
Published: March 2009

Design of gate location is a crucial factor in achieving product quality in injection
moulding. It Influences the manner of plastic flow into the cavity. The optimum gate location
improves quality and avoids products defects. This paper presents an investigation for the effects of
gate location on product quality in injection moulding. Plastic advisor, simulation software
embedded in Pro/Engineer package has been used for flow analysis of plastic product for selected
gate locations. It has been shown that optimum gate location improves cooling quality resulting in a
better product quality. The previous conventional experiences by individual credited engineers have
been considered.
Numerical Prediction of Influence of Diamond Burs on Subsurface Damage in Intraoral Adjustments of Porcelain Prostheses
Authors: Song Xiao Fei , Yin Ling
Published: March 2009

Failure rate is noticeably high in dental bioceramics for restorations even though progress
has been made in reinforcement of the materials. One of the major causes of failures is due to surface
and subsurface damage induced in intraoral adjustments. This process is a routine clinical procedure
for marginal and occlusal fit using high-speed dental handpieces and diamond burs. Material removal
using the diamond burs easily produce surface and subsurface damage in ceramic prostheses.
Therefore, it is essential to minimize the surface damage in clinical dentistry. In this paper, we
investigated the effect of diamond burs with coarse, medium and fine grit sizes on the degrees of
subsurface damage in in vitro dental adjustments via numerical modeling. Finite element analysis was
applied to model the dental adjusting processes and to predict the degrees of subsurface damage using
different grit sizes of diamond burs.
Magnesium and Magnesium Alloys as Degradable Metallic Biomaterials
Authors: Wang H. , Shi Zhi Ming , Yang K.
Published: March 2009

Drawbacks associated with permanent metallic implants lead to the search for degradable
metallic biomaterials. Magnesium alloys have been highly considered as Mg has a high biocorrosion
potential and is essential to bodies. In this study, corrosion behaviour of pure magnesium and
magnesium alloy AZ31 in both static and dynamic physiological conditions (Hank’s solution) has
been investigated. It is found that the materials degrade fast at beginning, then stabilize after 5 days
of immersion. High purity in the materials reduces the corrosion rate while the dynamic condition
accelerates the degradation process. In order to slow down the degradation process to meet the
requirement for their bio-applications, an anodized coating is applied and is proved as effective in
controlling the biodegradation rate.
Modification of Porous Alumina Ceramics with Bioinert and Bioactive Glass Coatings
Authors: Miao X.
Published: March 2009

Porous biomaterials including porous bioceramics play important roles for hard tissue
replacement and regeneration. I this paper, porous alumina (with and without zirconia addition)
ceramics were produced via coating polyurethane (PU) foams with Al2O3 (ZrO2) slurries, followed
by drying at room temperature and sintering at 1300 oC. The advantage of the PU foam method was
the achieved high pore interconnectivity, but the mechanical properties of the porous ceramics were
rather poor due to the high macroporosity and the high microporosity. To remove the microporosity
and strengthen the porous alumina ceramics, a lanthanum-modified aluminosilicate (LAS) glass was
used to infiltrate the alumina struts. Nevertheless, the resulting LAS-modified macroporous alumina
ceramics would have no ability to bond to bone tissues. To impart a bioactivity (i.e. the ability of
bone bonding) to the bioinert porous ceramics, a bioactive glass layer was applied by dipping with
the bioactive glass slurry and sintering at 1200 oC. The twice coated porous alumina ceramics
would exhibit high compressive strengths, allow bone tissue ingrowth, and form strong bonematerial
integration. A biodegradable filler – calcium phosphate cement was also incorporated. A
possible application of the porous bioceramics would be for the maxillofacial reconstruction.
Novel Synthetic Bio-Mimic Polymers for Cell Delivery
Authors: Xiao Yin , Peng Hui , Mao Xueli , Whittaker Andrew K. , Crawford Ross
Published: March 2009

Cell-based therapy is one of the major potential therapeutic strategies for cardiovascular,
neuronal and degenerative diseases in recent years. The aims of this study is to develop a novel biomimic
polymeric materials which will facilitate the delivery cells, control cell bioactivities and
enhance the focal integration of graft cells with host tissues. We synthesized a novel tri-block
copolymer, methoxy-terminated poly (ethylene glycol) (MPEG)-polyL-lactide (PLLA)-polylysine
(PLL) via sequential polymerization of PLLA onto MPEG, followed by ring opening polymerization
of PLL onto the functionalized chain end. The triblock copolymer (5%) was then mixed with high
molecular weight PLLA (95%) to form cell-delivery membranes. The spectra of copolymers were
determined by NMR and ATR-FTIR spectroscopy. Human osteoblasts were used for testing
biocompatibility and initial cellular reaction. It was noted that no cytotoxicity was detectable in our
synthesized copolymers. Compared with pure PLLA and diblock copolymers, the triblock
copolymers showed significantly better cell adhesion and proliferation. Interestingly we identified
that cellular activity (attachment, proliferation and differentiation) could be regulated by the
molecular weight and composition of the triblock copolymers. In conclusion controllable synthetic
copolymers can be designed and synthesized to modulate cellular function in facilitating tissue
repair and regeneration.
Endothelialisation and Cell Retention on Gelatin Chitosan-Coated Electrospun Polyurethane, Poly (Lactide-Co-Glycolide) and Collagen-Coated Pericardium
Authors: Patel Shital , Wong Cynthia , Morsi Yos S. , Mo Xiu Mei , Rui Chen
Published: March 2009

Arterial bypass and heart valve replacements are two of the most common surgical
treatments in cardiovascular surgery today. Currently, artificial materials are used as substitute for
these cardiac tissues. However, these foreign materials do not have the ability to grow, repair or
remodel and are thrombogenic, leading to stenosis. With the aid of tissue engineering, it is possible
to develop functional identical copies of healthy heart valves and arteries, which are biocompatible.
Although much effort has been made into this area, there are still inconsistencies with respect to
endothelialisation and cell retention on synthetic biological grafts. These variations may be
attributed to differences in factors such as cell seeding density, incubation periods and effects of
shear stress. In this study, we have compared the endothelialisation and cell retention between
gelain chitosan-coated electrospun polyurethane (PU), poly (lactide-co-glycolide) (PGA/PLA) and
collagen-coated pericardium. Endothelial cells adhered to all of the materials as early as 1–day post
seeding. After 7-day of seeding, the coverage on PU was almost 45% and that on PGA/PLA was
about 25% and the least was on collagen-coated pericardium of approximately 15%. It was observed
that the PU showed superior cell coverage and cell retention in comparison to the PGA/PLA and
collagen-coated pericardium.
Simulation of Three-Point Bending Test of Titanium Foam for Biomedical Applications
Authors: Kashef S. , Asgari S.A. , Hodgson Peter , Yan Wen Yi
Published: March 2009

Using Titanium (Ti) foam as an implant material is a new approach for biomedical
applications and it is important to understand the mechanical behaviors of this new foam material.
In the present study, the bending of the Ti foam has been simulated and compared against recently
published data [1]. FE Analysis has been performed by Abaqus software. Stiffness and Yield
strength of foams between 50% (cortical bone) to 80% (cancellous bone) porosity range were
considered. This study showed that crushable foam material model in Abaqus, which has
developed primarily for Aluminum (Al) foam alloys, is also valid for Ti Foam before any crack or
damage occurs in the sample.
Crystal Plasticity Finite Element Modelling of BCC Deformation Texture in Cold Rolling
Authors: Li Hei Jie , Han Jing Tao , Jiang Zheng Yi , Pi Hua Chun , Wei Dong Bin , Tieu A. Kiet
Published: March 2009

Taylor-type and finite element polycrstal models have been embedded into the commercial
finite element code ABAQUS to carry out the crystal plasticity finite element modelling of BCC
deformation texture based on rate dependent crystal constitutive equations. Initial orientations
measured by EBSD were directly used in crystal plasticity finite element model to simulate the
development of rolling texture of IF steel under various reductions. The calculated results are in good
agreement with the experimental values. The predicted and measured textures tend to sharper with an
increase of reduction, and the texture obtained from the Taylor-type model is much stronger than that
by finite element model. The rolling textures calculated with 48 {110}<110>, {112}<111> and
{123}<111> slip systems are close to the EBSD results.
Crack Analysis Using an Improved Meshless Technique with Irregular Nodes
Authors: Wang W.L. , Gu Yuan Tong , Zhang Liang Chi
Published: March 2009

Meshless method has advantages in analyzing the deformation around a crack. However,
the effectiveness of such method is influenced by the treatment of local support domain which is a
base for an appropriate selection of field nodes in the construction of shape functions. In the current
practice, the methods to determine support domain have some drawbacks. It is therefore beneficial
to develop a more flexible technique for determining the support domain in crack simulation. This
paper presents such a technique which could be used in both regularly and irregularly distributed
nodes. Numerical examples show that the technique produces accurate results in these two
situations. Moreover, the new technique can be integrated with different types of meshless methods
to provide an effective way in handling arbitrary nodal distribution to meet the needs of solutions to
problems with complex geometric boundaries.
Multiscale Particle-In-Cell Modelling for Advanced High Strength Steels
Authors: Asgari S.A. , Hodgson Peter , Lemiale Vincent , Yang C. , Rolfe Bernard F.
Published: March 2009

Advanced High Strength Steels (AHSS) offer outstanding characteristics for efficient and
economic use of steel. The unique features of AHSS are direct result of careful heat treatment that
creates martensite in the steel microstructure. Martensite and carbon content in the microstructure
greatly affects the mechanical properties of AHSS, underlining more importance on microstructural
discontinuities and their multiphase characteristics. In this paper, we present the Multiscale
Particle-In-Cell (MPIC) method for microstructural modelling of AHSS. A specific particle method
[1] usually used in fluid mechanics is adapted and implemented in a parallel multiscale framework.
This multiscale method is based on homogenisation theories; with Particle-In-Cell (PIC) method in
both micro and macroscale, and offers several advantages in comparison to finite element (FE)
based formulation. Application of this method to a benchmark uniaxial tension test is presented and
compared with conventional FE solutions.
Effect of Iron Content on the Properties of FePt Nanoparticles in Water in Oil Microemulsions
Authors: Hyie Koay Mei , Yaacob Iskandar Idris
Published: March 2009

Fe/Pt bimetallic nanoparticles at various molar ratios have been prepared by
simultaneous reduction of FeCl2 and H2PtCl6 with hydrazine hydrate in water/Triton X-
100/cyclohexane/pentanol microemulsions at room temperature. The size, structure, composition
and the magnetic properties of the resultant nanoparticles were characterized by XRD, EDX, TEM
and AGM. XRD patterns indicated the formation of face centered cubic FePt nanoparticles with
crystallite size in the range of 4 nm to 8 nm. Higher content of iron resulted in larger FePt
nanoparticles. EDX analyses on the samples confirmed the presence of Fe and Pt elements in the
particle. The composition for each particle was roughly consistent with the Fe2+ to Pt 4+ ratio of
initial solution. TEM micrograph showed homogeneous fine spherical particles. The physical sizes
were similar to the crystallite sizes of FePt nanoparticles calculated from XRD. The Fe/Pt molar
ratio of 1 to 1 showed optimum magnetic properties with coercivity (Hc) of 68.67 Oe .
Nonlinear Analysis of a Ball Grid Array Package under Thermal Cycles
Authors: Bai Ruixiang , Jiang H. , Yan Cheng
Published: March 2009

In this study, the stress-strain distributions and interface failure in a BGA (Ball Grid
Array) package subjected to thermal cycling were investigated using 2D and 3D finite element
analyses. The viscous behavior of the adhesive material and thermal mismatch between the
dissimilar materials in the package were considered. The potential failure sites in the solider and
adhesive joints were analyzed.
Residual Stress Estimation of Tungsten Film by GIXRD
Authors: Chen Chao Chang Arthur , Fu Wei En , Chen Meng Ke
Published: March 2009

Subsurface residual stresses of tungsten films induced by Chemical Mechanical Polishing
(CMP) processes were investigated by the Grazing Incident X-Ray Diffraction (GIXRD). Basis of the
GIXRD measurement was introduced and the experiments were conducted for residual stress of
tungsten film measurements. Experimental procedures of the GIXRD measurements were presented.
The obtained residual stresses value of tungsten films from 800 nm to 400 nm varies from 1086.1 ±
105.2 MPa to 1670.6±103.4 MPa prior and after CMP process.
Stress Corrosion Cracking of NiTi Orthodontic Wires in Sodium Fluoride Solution
Authors: Li Xiao Ji , Wang Jian Qiu , Han En-Hou , Ke Wei
Published: March 2009

The influence of fluoride on stress corrosion cracking (SCC) of NiTi orthodontic wires
was investigated using slow strain rate test (SSRT) and scanning electron microscopy (SEM). The
results indicated that fluoride significantly accelerated the stress corrosion cracking of NiTi
orthodontic wires. The fractographies of NiTi orthodontic wires exhibited striation pattern.
Experimental Research on Grain Orientation Evolution of Extruded Mg Alloy AZ31B Sheet during Uniaxial Tensile Deformation
Authors: Zhang Shi Hong , Li Zhang Gang
Published: March 2009

The orientation rotation in extruded Mg alloy AZ31B sheets during uniaxial tension at
room temperature has been investigated using SEM/EBSD technique. According to the
experimental results and the calculated results of Sachs crystal model, the quantitative rule of the
tensile axis rotation for the grains (parent), and the associated slip systems have been analyzed in
detail. The influencing factors of twinning area fraction have also been studied. The results show
that the rule of the rotation of tensile axis can be explained by cross slip systems; the grains with
different initial orientations exhibit different twinning behaviors; the area fractions of extensive
twins have a close relationship with Schmid factors of tensile twinning, and with the angle between
c-axis and tensile axis of the grains.
Thermal Properties and Fire Performance of Woven Glass Fibre Reinforced Nylon 6 Nano-Composites with Carbon Nanotubes
Authors: Shen Shirley Zhiqi , Bateman Stuart , Yuan Qiang , Dell'Olio Mel , Gotama Januar , Wu Dong Yang
Published: March 2009

This paper presents the effects of incorporating carbon nanotubes (CNT) into nylon 6 on
thermal properties and fire performance of woven glass reinforced CNT/nylon 6 nanocomposite
laminates. Incorporation of CNT in nylon 6 improved the thermal stabilities, thermal conductivity
and fire performance of laminates without compromising their mechanical properties. The thermal
conductivity of laminates with 2 wt% CNT increased up to 42% compared to that without CNT.
The ignition time and peak HRR time was delayed approx. 31% and 118%, respectively, in
laminates with 4 wt% CNT in nylon 6 over that without CNT.
Micro Impact Testing of Lead Free Solder Joints
Authors: Rajoo Ranjan , Kisi Erich H. , O'Connor D.J.
Published: March 2009

This paper presents data obtained from a newly-developed instrument to test the quality
of solder interconnections at high strain rate – the ‘micro-impactor’. This shear test of the
interconnection at high strain rate mimics the stress experienced by the solder joint when
undergoing shock due to drop-impact. Instrumented with a load cell and linear variable
displacement transducer (LVDT), it also has the ability to provide dynamic impact force and
displacement data. Earlier concepts to characterise the solder joint at high strain rates such as the
miniature pendulum impact tester [1] lacked this capability. This micro-impactor was used to study
the effect of increasing silver (Ag) and copper (Cu) concentration in solder alloys on the shear
strength of the solder joint. The performance of these lead-free alloys was also compared to that of
the well-established leaded solder. It was found that increasing the silver content increases the yield
strength of the solder, causing the failure to occur at the brittle intermetallic layer instead of in the
bulk of the solder.
Instability of Heated Panels in Supersonic Air Flow
Authors: Yang Zhi Chun , Xia Wei
Published: March 2009

An investigation on the stability of heated panels in supersonic airflow is performed. The
nonlinear aeroelastic model for a two-dimensional panel is established using Galerkin method and the
thermal effect on the panel stiffness is also considered. The quasi-steady piston theory is employed to
calculate the aerodynamic load on the panel. The static and dynamic stabilities for flat panels are
studied using Lyapunov indirect method and the stability boundary curve is obtained. The static
deformation of a post-buckled panel is then calculated and the local stability of the post-buckling
equilibrium is analyzed. The limit cycle oscillation of the post-buckled panel is simulated in time
domain. The results show that a two-mode model is suitable for panel static stability analysis and
static deformation calculation; but more than four modes are required for dynamic stability analysis.
The effects of temperature elevation and dimensionless parameters related to panel length/thickness
ratio, material density and Mach number on the stability of heated panel are studied. It is found that
panel flutter may occur at relatively low aerodynamic pressure when several stable equilibria exist for
the aeroelastic system of heated panel.
Meso-Macro Scale Behavior Analysis of Polymeric Systems under their Melting States
Authors: Yu Ying Hao , Gheni Mamtimin , Lu Zhong Yuan , Jiang Wei
Published: March 2009

In this study, the meso-scale analysis are conducted by using the Disperse Particle
Dynamics(DPD) analysis, and the constitutive equation model between viscosity and shear velocity
are obtained by using different constrained mutual sufficient area. The macro-scale analysis are
conducted by using Finite Element Method(FEM) based on the Computational Fluid
Dynamics(CFD). The meso-scale model is smoothly coupled with in macro-scale model by using the
relationships between the DPD meso-scale model and the FEM macro-scale model.
Stability Analysis of Earth Dam under Unsaturated Seepage
Authors: Xiao Zheng Hua , Han Bo , Tuohuti Akenjiang , Liao Hong Jian
Published: March 2009

This paper is mainly concerned with the saturated-unsaturated seepage analysis of earth
dams based on unsaturated soil theory and the stability analysis of earth dams based on conception
of slices. At first, beginning basic seepage theory, thesis introduce the saturated-unsaturated and
steady-unsteady seepage differential equation of porous media and the FEM regarding hydraulic
pressure head as basic unknown quantity. Then considering the shear strength of unsaturated soil,
the method of analysis of general limit equilibrium has been approved and it can be used in the
analysis of the stability of saturated-unsaturated slopes. Through an example it is respectively
discussed effects of seepage flow when water head is changed in earth dam and the effects of
percolation in the stability of the earth dam slope. Some helpful conclusions are gained. This can be
making the best of the tow methods and the results can be used in engineering for reference.
Uniaxial Ratchetting-Fatigue Interaction of Tempered 42CrMo Steel and its Failure Model
Authors: Kang Guo Zheng , Liu Yu Jie , Gao Qing
Published: March 2009

Uniaxial ratchetting-fatigue interaction of tempered 42CrMo alloy steel was observed by
various cyclic stressing tests at room temperature. The ratchetting deformation and low cycle fatigue
(LCF) property of the material as well as their interaction occurred in cyclic stressing were discussed.
It is shown that progressive ratchetting deformation causes the decrease of fatigue life, and the fatigue
life of the material depends greatly upon the applied mean stress, stress amplitude, maximum stress
and stress ratio. Since tempered 42CrMo steel presents significant cyclic softening feature, a tertiary
ratchetting is observed. Based on the experimental results, a simple and reasonable failure model
convenient to engineering application was constructed to predict the fatigue life of the material in
uniaxial cyclic stressing. The basic variables of the model are maximum stress and stress ratio, and
the effect of cyclic softening feature on the ratcheting-fatigue interaction is also included in the model
by introducing a new variable. It is shown that the predicted lives are in fairly good agreement with
the experimental ones.
Acoustic Emission Signals in the Micro-EDM of PCD
Authors: Mahardika M. , Mitsui Kimiyuki , Taha Zahari
Published: March 2009

The mechanism of fracture in micro-electrical discharge machining (-EDM) processes is
related to the discharge pulses energy. This paper investigates the correlation of fractures and
discharge pulses energy in the -EDM of polycrystalline diamond (PCD) to the acoustic emission
(AE) signals. The evaluation of fracture mechanism was done by measuring the generation and
propagation of elastic wave in single discharge pulse by using AE sensor. The results show a strong
correlation between fractures and discharge pulses energy to the AE signals and mechanism of
material removal in the -EDM processes.
Study on Center Hole Deformation Test of Rigid Bearing Plate
Authors: Zhang Jian Guo , Zhang Qiang Yong , Yang Wen Dong , Zhang Ying
Published: March 2009

The center hole deformation test of rigid bearing plate is an important method for
understanding deformation properties of deep weak rock mass. According to the center hole
deformation test of rigid bearing plate in dam zone of Dagangshan hydropower station, this paper
detailedly recommends test method of this experiment, and the settlement deformation formula of
deep rock mass under circular rigid bearing plate is deduced, which could be used to calculate
deformation modulus and equivalence deformation modulus of different deep rock mass at test
points. According to curves of depth-deformation under different pressures at test points in dam zone,
we have analyzed deformation characteristics of deep weak rock mass. By the center hole deformation
test of rigid bearing plate, stratum properties in dam zone of Dagangshan hydropower station could be
understood further, and it provides important references for the study of creep speciality of weak rock
mass in dam zone.
Experimental and Computational Studies of Twin-Vertical-Tail Buffet
Authors: Yang Qing , Li J.J. , Yang Y.N. , Ye Z.Y.
Published: March 2009

Characteristics and mechanism of twin-vertical-tail buffet response on airplane
configuration with wing root leading edge extension (LEX) were studied by both experiment and
computation. Low-speed wind tunnel experiments were carried out to measure the root bending
moment and tip acceleration of vertical tail. Vortical flow patterns were visualized via laser light
sheet technique. Three-dimensional computation was performed to solve the unsteady Euler
equations on rigid model. The results indicate that (1) bursting of vortices emanating from LEX is the
main source of twin-vertical-tail buffet; (2) the Euler equations is able to predict the general
characteristics of vertical-tail buffet response reasonably.
Robust Flutter Analysis of an Airfoil with Flap Freeplay Uncertainty
Authors: Yang Zhi Chun , Gu Ying Song
Published: March 2009

Modern robust flutter method is an advanced technique for flutter margin estimation. It
always gives the worst-case flutter speed with respect to potential modeling errors. Most literatures
are focused on linear parameter uncertainty in mass, stiffness and damping parameters, etc. But the
uncertainties of some structural nonlinear parameters, the freeplay in control surface for example,
have not been taken into account. A robust flutter analysis approach in μ-framework with uncertain
nonlinear operator is proposed in this study. Using describing function method the equivalent
stiffness formulation is derived for a two dimensional wing model with freeplay nonlinearity in its
flap rotating stiffness. The robust flutter margin is calculated for the two dimensional wing with flap
freeplay uncertainty and the results are compared with that obtained with nominal parameter values. It
is found that by considering the perturbation of freeplay parameter more conservative flutter boundary
can be obtained, and the proposed method in μ-framework can be applied in flutter analysis with other
types of concentrated nonlinearities.