bluuebunny/crossref_metadata_2025 huggingface dataset:
Double-Layer Bioactive Glass Coatings Obtained by Pulsed Laser Deposition
Authors: Veljković Dj. , Tanaskovic D. , Petrović R. , Janaćković Dj. , Mitrić M. , Cojanu C. , Ristoscu C. , Mihailescu Ion N.
Published: March 2009

Pulsed laser deposition was used to obtain functionally graded bioactive glass coatings on
titanium substrates. An UV KrF* (λ=248 nm, τ>7 ns) excimer laser was used for the multi-pulse
irradiation of the targets. The depositions were performed in oxygen while keeping substrate
temperature at 400°C. We used sintered glass targets in the system SiO2-Na2O-K2O-CaO-MgOP2O5
that differed in SiO2 content, which was either 57 wt.% (6P57) or 61 wt.% (6P61). A glass
6P61 was used as the first layer in direct contact with the metallic substrate, while the outer
bioactive layer was made of glass 6P57. Both the bioactive coatings and the bulk glasses were
analyzed by Fourier transform infrared spectrometry (FTIR), grazing incidence X-ray diffraction
(GIXRD), and scanning electron microscopy (SEM). The FTIR spectra of the glass powders and
glass coatings showed the main vibration modes of the Si-O-Si groups. GIXRD analysis confirmed
that the glass coatings had an amorphous structure. The SEM micrographs of the glass coatings
showed the films to consist of droplets with diameters ranging from 0.2 to 5 μm. SEM was used to
determine the rate of apatite formation on the coating when exposed to simulated body fluid (SBF)
solution for 7 days. We demonstrated that pulsed laser deposition leads to good glass-metal
adhesion on the substrate and well attached bioactive particles on the surface. We consider therefore
this method appropriate for forming implants that can develop an apatite layer after immersion in
SBF.
Effect of Added Tricalcium Phosphate on Basic Properties of Apatite Cement
Authors: Takeuchi Akari , Nakagawa Akinari , Matsuya Shigeki , Kunio Ishikawa
Published: March 2009

Effect of added α-tricalcium phosphate (α-TCP) and β-TCP was investigated to
understand the setting reaction of apatite cement consisting of tetracalcium phosphate (TTCP) and
dicalcium phosphate anhydrous (DCPA). Addition of TCP delayed the initial setting time because
TCP was not involved in the initial setting reaction and resulted in the decreased initial mechanical
strength. After the initial setting of the cement due to the conversion of TTCP and DCPA into apatite,
α-TCP dissolved to supply calcium and phosphate ions and they were consumed for crystal growth of
apatite. Therefore, mechanical strength of the apatite cement containing α-TCP was increased. In
contrast, added β-TCP showed no reactivity in the cement and thus result in the decreased mechanical
strength.
Accelerating the Setting of Portland Cement Based Dental Materials Using Calcium Sulphates
Authors: O’Beirne J.L. , Shelton R.M. , Lumley P.J. , Hofmann M.P.
Published: March 2009

Mineral trioxide aggregate (MTA) is a Portland cement (PC) based material used for
sealing root canals however it has a long setting time which is undesirable for dental applications.
This study investigated the effect of three different calcium sulphate additions for accelerating the
initial setting of a PC based dental material, whilst attempting to maintain its high compressive
strength and low relative porosity. Anhydrous calcium sulphate (CaS), Plaster of Paris, calcium
sulphate hemihydrate (PoP) and Gypsum, calcium sulphate dihydrate (Gyp) were each added to PC
at 5wt%, 10wt% and 20wt%. Initial setting times, compressive strengths and relative porosity were
measured using the Gilmore Needles Test, a universal testing machine and a helium pycnometer
respectively. Scanning electron microscopy (SEM) was used to observe any microstructural
changes in cements. PoP and CaS had the most profound influence on the setting of PC. 20wt%
CaS had the greatest effect on the setting time of PC (10min) although decreased the compressive
strength by up to 40%, which may have arisen from the formation of microcracks, observed by
SEM analysis. Additions of 10wt% PoP and CaS may have the potential to reduce the long setting
time of PC based dental materials.
A Comparative Study between β-TCP Prepared by Solid State Reaction and by Aqueous Solution Precipitation: Application in Cements
Authors: Oliveira Aline P. , Motisuke M. , Leal Claudinete V. , Beppu Marisa Masumi
Published: March 2009

It is well known that calcium phosphate compounds are widely used as bone substitute due to their
biocompatibility and bioactivity. Furthermore, recent studies have shown that slight changes in morphology
or crystal structure can lead to several in vivo behaviours. Therefore, the purpose of this study was to
investigate two different β-TCP synthesis routes (solid state reaction and aqueous solution precipitation) and
their consequences on the final cement properties. It was found out that both routes are equivalent as there
were no significant differences on their cement properties, except for mechanical resistance. The latter
difference can also be attributed to the difference on the particle size distributions of the obtained β-TCP.
These facts indicate that solid state reaction route is more interesting given its simplicity and yield.
Heavy Metals Immobilization by Hydroxyapatite-Alginate Composite in Simulated Gastric Fluid
Authors: Mavropoulos Elena , da Rocha Nilce C.C. , Rocha-Leão Maria Helena M. , Prado da Silva Marcelo Henrique , Rossi Antonella M.
Published: March 2009

Micrometric sphere beads of HA-alginate composite were produced to remove Pb2+ and
Cd2+ from contaminated gastric fluid. It was shown that the composite was effective in Pb2+ and
Cd2+ immobilization from high-contaminated simulated gastric fluid. X-ray diffraction and
scanning electron microscope analyses performed on HA-alginate beads after the Pb2+ uptake
showed that lead phosphate, (Pb10-x Cax (PO4)6Cl2), was precipitated on beads surface. X-ray
diffraction patterns of HA powder after Cd2+ sorption experiments showed no evidence of other
phases, however, dispersive energy spectrometer analyses of the HA-alginate confirmed the
presence of Cd2+ on the composite surface. Desorption experiments in simulated enteric fluid
showed that composite beads containing Pb2+ and Cd2+ remained stables for one hour in simulated
gastrointestinal fluid. The results reinforce the hypothesis that HA-alginate composite can be a very
efficient system for Pb2+ and Cd2+ uptake from contaminated gastrointestinal fluid preventing
systemic contamination by bloody stream uptake.
Research on the Curving Aragonite Sheets in Clam’s Shell
Authors: Chen Bin , Peng Xiang He , Sun Shi Tao
Published: March 2009

Molluscan shell possesses excellent strength, stiffness and fracture toughness that are
closely related to its exquisite microstructure. SEM observation of a clam’ shell showed that the
shell is a kind of bioceramic composite consisting of aragonite and protein layers parallel with the
surface of the shell. The observation also showed that the aragonite layers are composed of long and
thin aragonite sheets. Many aragonite sheets are of curving shape at the center of the shell. The
higher fracture toughness of the shell was analyzed based on the representative model of the
curving aragonite sheets and the concept of the maximum pullout force that is related to the fracture
toughness of the shell. The analytical result showed that the maximum pullout force of the curving
aragonite sheet is larger than that of straight aragonite sheets, which may effectively enhance the
fracture toughness of the shell.
Gap Effect on the Heterogeneous Nucleation of Apatite on Thermally Oxidized Titanium Substrate
Authors: Sugino Atsushi , Uetsuki Keita , Tsuru Kanji , Hayakawa Satoshi , Ohtsuki Chikara , Osaka Akiyoshi
Published: March 2009

Apatite formation on the surface of materials in body environment is an essential condition
to show osteoconduction after implantation in bony defects. This study reports the novel technique for
providing the apatite-forming ability to titanium metals by only controlling the spatial gap and
thermal oxidation. Two pieces of titanium thermally oxidized at 400 °C were set together like V-letter
with varied mouth opening. They showed the formation of apatite on both facing surface after
exposure to a simulated body fluid (SBF) proposed by Kokubo and his colleagues, when the gap was
less than approximately 600 μm. Moreover, specimens with micro-grooves of 500 μm in depth and
200-1000 μm in width was able to form apatite in SBF with in 7 days, after they were thermally
oxidized at 400 oC. These results indicated that the titanium metals were provided with
apatite-forming ability, i.e. osteoconduction, due to controlled gap with thermally oxidized surface.
Hence, we conclude that bioactive titanium substrate showing osteoconduction can be produced by
designed machining followed by thermal oxidation at an appropriate temperature.
Evaluation and Characterization of TiAlZr Alloys Coated with Apatite or Albumin-Apatite Composite
Authors: Ionita D. , Aldea E. , Stanciu G. , Demetrescu Ioana
Published: March 2009

The aim of this paper was to find and establish the contact: biomaterial implant
(TiAlZr) - coated with biologically active molecules; and the correlation between surface
characteristics and their efficiency.
Stability of Bioactivated Co-Cr Alloys in Biological Environment
Authors: Sovar M.M. , Ducu C. , Iordachescu D. , Demetrescu Ioana
Published: March 2009

The present work is focused on the stability of bioactivated CoCr alloy in biological
environment (buffered saline solution (PBS), lactic acid, citric acid). The chemical and
electrochemical deposition was characterized by electrochemical methods (open circuit potential,
cyclic voltametry), scanning electronic microscope (SEM), x-ray diffractometer (XRD), inductively
coupled plasma/mass spectrometry (ICP/MS) and citotoxicity test. The results prove a good
electrochemical stability in all cases.
Environmental Phase Stability of Ceramics Composite for Hip Prostheses in Presence of Surface Damage
Authors: Yamada Kiyotaka , Pezzotti Giuseppe
Published: March 2009

Alumina matrix composite (AMC) has been widely used for artificial hip and knee joints because of its phase stability in human body and its excellent wear resistance. The excellent mechanical properties of strength and fracture toughness of zirconia materials are well known to be closely related to stress-induced transformation from the tetragonal to the monoclinic phase, which is accompanied with 4% volume increase of the zirconia crystal cell. However, it is also to be considered that the material is prone to low temperature aging degradation (LTAD) under hydrothermal environment, like in the human body. This LTAD is influenced by the tetragonal to the monoclinic (t-m) phase transformation. T-m transformation also induces the formation of microcracks at the material surface, and an increase in surface. Microcracking leads to a decrease of mechanical properties, and could explain the failure of implants after some years in vivo [1, 2] .Therefore, it is very important to study how to prevent phase transformation in zirconia components. Transformed monoclinic zirconia percentage can be experimentally measured by Raman spectroscopy and the residual stress distribution, which is related to phase transformation, can be determined by a non-destructive piezo-spectroscopic analysis. In this paper, we attempted to evaluate it from both stress and mechanical properties points of view by confocal Raman and fluorescence spectroscopy.
Non-Destructive Stress Evaluation on Ce-TZP/Al2O3 Nanocomposite-VINTAGE ZR T-Glass Systems by Confocal Fluorescence Piezo-Spectroscopy
Authors: Yamada Kiyotaka , Nawa Masahiro , Pezzotti Giuseppe
Published: March 2009

In the area of dental treatment for crown and dental implants, ceramics restoration is
becoming popular due to both aesthetic needs and release of metallic allergy. However, for the
restoration of defected tooth, ceramics materials with higher reliability than that of conventional
glass or alumina have been required, thus raising expectations for zirconia ceramics. Since residual
stress play a significant role in the reliability of dental implants, in this paper, a non-destructive
assessment of residual stress is presented for a zirconia-substrate/VINTAGE ZR T-Glass system
using confocal fluorescence microprobe spectroscopy.
In Vitro Bone Formation on Bioactive Titanium
Authors: Isaac Juliane , Loty S. , Hamdan A. , Kokubo Tadashi , Kim Hyun Min , Berdal A. , Sautier J.M.
Published: March 2009

Titanium has limitations in its clinical performance in dental and orthopaedic
applications. Over the last decade, numerous implant surface modifications have been developed
and are currently used with the aim of enhancing bone integration. In the present study, we have
experimented a bioactive titanium prepared by a simple chemical and moderate heat treatment that
leads to the formation of a bone-like apatite layer on its surface in simulated body fluids. We haved
used foetal rat calvaria cell cultures to investigate bone nodule formation on bioactive titanium.
Scanning electron microscopy (SEM) showed that cells attached and spread on the bioactive
surfaces. After 22 days of culture, bone nodules were detected on the material surface. Furthermore,
the mineralized bone nodules remained attached to the bioactive titanium surface but not to
untreated titanium. SEM observations and EDX microanalysis of sectioned squares showed that
bone-like tissue directly bonded to bioactive titanium, but not pure titanium. These results indicated
the importance of the implant surface composition in supporting differentiation of osteogenic cells
and the subsequent apposition of bone matrix allowing a strong bond to bone. Furthermore, these
findings may provide promising strategies for the development of biologically active implants.
Development of Measurement and Assessment Technology for Evaluation of Bone Regeneration
Authors: Kotobuki Noriko , Hirose Motohiro , Ioku Koji , Sakaguchi Akira , Iwama Akifumi , Harada Masaki , Yamamoto Hiroshi , Ohgushi Hajime
Published: March 2009

Since 2001, we have clinically utilized human bone marrow-derived mesenchymal stem
cells (MSCs) for bone regeneration. The osteogenic ability of MSCs has been assessed by measurement
of alkaline phosphatase activity and calcium deposition. As for the detection of in vitro
calcium deposition, we have established the method using calcein, which is a calcium-binding fluorescence
material. Using this fluorescence material, we could observe the calcium deposition and then
estimate the value of calcium deposition. In this report, we cultured rat MSCs on culture plate as well
as transparent β-TCP, and calcium deposition was visualized and quantitated using an image analyzer.
After 2 weeks differentiation of rat MSCs to osteoblasts, calcium deposition on β-TCP was observed
as a signal of calcium-binding fluorescence. This fluorescence signal was also quantitated with an
image analyzer.
A Quasi-Steady-State Thermal Model for Laser-Assisted Cutting of Zirconia Ceramics
Authors: Ho Ching Yen , Wen Mao Yu , Lin Shih Yu
Published: March 2009

This study has developed a thermal model for laser-assisted cutting of zirconia ceramics. Laser-assisted cutting can increase ceramics removal rates by utilizing a localized heat source to elevate the workpiece temperature prior to material removal with traditional cutting tool. At high temperatures the yield strength of ceramics can decrease below the fracture strength, changing the material deformation behavior from brittle to ductile and enabling the use of a single point cutting tool to remove material at rates approaching those of metal cutting. A thermal model has been developed for the workpiece of ceramics cylinder rotating with a constant speed, which was preheated by a laser and cut by cutting tool. Since the cutting tool followed the moving laser with a fixed distance in the axial direction, i.e. the feed rate of the cutting tool was the same as the moving velocity of the laser, this thermal model has been formulated in a cylindrical coordinate system that moved with the laser beam or cutting tool and therefore, this problem was a quasi-steady-state problem. An analytical solution for this thermal model has been obtained. The results calculated by this model agree with the available experimental data. The temperature field is presented during laser-assisted cutting of ceramics. The effects of feed rate and laser power on temperature field are also discussed in this study.
Light Guide Plate Based on Sub-Micron Gratings
Authors: Ye Yan , Chen Lin Sen
Published: March 2009

A novel light guide plate (LGP) with sub-micron gratings (SMGs) on its upper surface is
proposed to control the illumination angle and its initial structure of LGP is given. The periods of
SMGs are 0.651μm, 0.516μm and 0.433μm for the LED light sources transmit out vertically with
the incidence angle 45º under the total internal reflection condition. The transmission efficiencies
vary between 2% and 43% when the depth of grooves of SMGs changes between 0.05 μm and 0.9
μm by using rigorous coupled-wave theory (RCWT). The results show that the LGP utilizing the
characteristics of the SMGs can control the transmission angle and get homogeneous output.
Key Issues in Measuring the Velocities of Nanoparticles in Nanofluids
Authors: Qian Ming , Ni Xiao Wu , Lu Jian , Shen Zhong Hua
Published: March 2009

Our recent work [1] theoretically revealed that speckles can be formed when nanofluids
containing a modest volume fraction of nanoparticles are illuminated by a monochromatic laser
beam. This paper focuses on the key issues, including the experimental setup, the particle volume
fraction of the nanofluid, the flow velocity of the nanofluid and the diameter of the pipe, in
measuring the velocities of nanoparticles in nanofluids with laser speckle velocimetry (LSV). First
an experimental setup is established according to the optical characteristics of nanoparticle and the
measuring principles of particle image velocimetry (PIV) and LSV. Then a conclusion is made from
the experimental results that clear speckle patterns can be formed when the particle volume fraction
is between 0.0005% and 0.002% is able to form. Finally, in order to make it applicable to utilize
LSV to measure the velocities of nanoparticles in nanofluids that flow in pipe, nanofluids can not
flow too fast and the diameter of the pipe should not be too small.
Machinability in Precision Grinding of Aspheric Optical Lens with Diamond Wheel
Authors: Baek Seung Yub , Lee Jung Hyung , Lee Eun Sang , Lee Jung Taik
Published: March 2009

In order to do the precision grinding of optical aspheric lens, it is essential to achieve
high quality surface roughness. Experiments show that the contacting area between the wheel and
workpiece in a grinding process is critical to influence the surface roughness for a fine grit size
resin bonded wheel. The precision grinding are performed with BK7 optical lens. This paper deals
with the grinding of an aspheric surface optical lens by diamond wheel. This study also compares
each machining parameter (work spindle speed, wheel spindle speed, feedrate, etc.) in rough
grinding, fine grinding and polishing on the aspheric lens. In this study, several experiments were
carried out BK7 optical glass lens by using vitrified, metal, resin bond diamond wheel and the
polisher of urethane ball was used to remove the tool marks with an ultra-precision in-line grinding
system. It was found that machining parameters significantly influence the surface roughness of
aspheric optical lens.
Inspection Technology for F-Theta Lens: Practices and Discussions
Authors: Li Hua , To Suet , Kong Ling Bao , Cheung Chi Fai , Lee Wing Bun
Published: March 2009

This paper presents the inspection technology for a freeform surface component which is named F-theta lens. F-theta lens is widely used in laser scanners, printers, etc. Freeform characterization is one of the main approaches to verify the manufacturing precision of freeform surface. At present, there is still a lack of techniques for the characterization of freeform surfaces. This study aimed to explore some approaches to inspect freeform surfaces. Two types of measurement methods, namely contact and non-contact measurement methods, are employed to measure the F-theta lens surface. The pros and cons, the existing problems, different applications and areas for improvement of the two methods are discussed. A series of advanced measuring instruments are used in the measurement process. A brief description of measurement mechanisms of these instruments is also presented. As a whole, this paper contributes to the development of the precision measurement technology for optical freeform surfaces.
Free-Form Reflector Design Using Differential Evolution Algorithm
Authors: Yang Bo , Jin Guo Fan , Wang Yong Tian
Published: March 2009

NURBS surface representation, combined with Differential Evolution (DE), enables us to perform automated non-imaging reflector design. The overall result is a simple automated nonimaging reflector design technique and only a little data such as desired illuminance distribution and searching limits are needed. Merit functions specific to non-imaging reflector design are presented. Using different merit functions, the generated illuminance distribution can be uniform as well as concentrated. DE is performed to obtain the reflector that generates the desired illuminance distribution. The photometric distributions are calculated through Monte-Carlo ray tracing and the illuminance value is used to calculate the merit function value. The validity of the proposed approach is demonstrated by optimization examples. Almost the same uniform illuminance distribution can be obtained using the algorithm proposed in this paper as that obtained by edge-raymethod. A concentrated illuminance distribution can also be generated using the algorithm proposed.
Polarization Variation of Laser Beam Intervening Multiple Reflections within a Paraboloid of Revolution-Shaped Cavity
Authors: Ho Ching Yen , Wen Mao Yu , Tsai Jui Chang
Published: March 2009

This paper investigates that polarizations of a laser vary in the process of reflections after
a linearly or circularly polarized beam is incident on a paraboloid of revolution-shaped cavity. This
analysis is based on the viewpoint of geometry optics because the opening radius is about 100μm,
which is ten times the size of the wavelength 10.6μm of an incident CO2 laser beam. Considering
the profile of laser beam to be Gaussian distribution, the variation of polarization in the process of
reflections is mathematically modeled. The result reveals that the state of polarization for an
incoming ray with circular polarization is almost totally transformed into linear polarization
perpendicular to the plane of incidence after the ray intervenes multiple reflections. The effects of
cavity depth and absorptive index of material on the polarization variation are also discussed. The
circularly polarized ray entering the deeper cavity is finally changed into the higher degree of linear
polarization. The increase in absorptive index reduces the speed approaching the linear polarization.
Uniformity Analysis of the Passive Film for SS316 Stainless Steel
Authors: Lee Shuo Jen , Lai J.J. , Lee Yu Ming , Ger Ming Der , Cheng S.W.
Published: March 2009

Passive film of stainless steels possesses good corrosion resistant property. However, the
passive film formed in nature is not uniform and the quality is not consistent. It is the major causes
for local corrosion. The pitting potential test is a traditional method to test local corrosion of
stainless steels. The local corrosion is usually induced by the break-down of the passive film.
Therefore, it can be utilized to evaluate the quality of the passive film. Also, because the pitting test
is quick and inexpensive, many tests can be performed to evaluate the uniformity of the passive
film. This study focuses on SS316 stainless steel. The specimens were treated with electropolishing
processes. The original and the processed specimens were tested by pitting potential tests. From
these results, the distribution and the uniformity of passive film could be evaluated. An efficient and
inexpensive index of the uniformity of the passive film is proposed.
Dynamic Characteristics in Cutting Processses for Precision Machining
Authors: Lin Shen Yung , Fang Y.C.
Published: March 2009

The accuracy and surface roughness of a machined component is strongly dominated by
the dynamic characteristics of the machine tool while the most important factor related to precision
machining is the dynamic behaviors during cutting processes. The main objective of this study is to
develop a thermo-elastic-plastic coupling dynamic cutting model under large deformation for
precision machining and so that the model can be used to predict several variations of cutting
mechanics variables. The flow stress in the model is considered as a function of strain, strain rate
and temperature and the critical value of the strain energy density of the workpiece is utilized as a
chip separation criterion. A powerful FEM software is adopted to create a complete numerical
solution for this model. During the analysis, the cutting tool is incrementally advanced forward in a
step-by-step manner, from an incipient stage of tool-workpiece engagement to a steady state of chip
formation. Three different dynamic cutting processes are introduced in this study, i.e., wave cutting,
wave removing and wave on wave cutting. Various levels of frequencies, of amplitudes and of
phase angle associated with different kinds of sinusoidal surface waviness are arranged during each
simulation case. A whole simulation of dynamic cutting process is undertaken and the fluctuations
of the dynamic cutting force during each dynamic cutting process are determined.
The Influence of Surfactant CTAB on the Microstructure and Material Properties of Nickel Microelectroforming
Authors: Chen Yann Cheng , Kuo Sheng Lung , Lee Jeou Long , Ke Shih Tsung , Wong Chia Hao , Ger Ming Der
Published: March 2009

The influence of surfactant CTAB (cetyl trimethyl ammonium bromide) on electrodeposited
nickel layer has been investigated in this research. Our result shows that CTAB added in
the electrolysis bath can effectively remove the hydrogen to obtain a smoother nickel layer. The
effect of CTAB on the surface roughness is also significant. It may be ascribed to the adsorption of
CTAB on the electrode surface which results in a hindering effect in the electrodeposition process.
Increasing the concentration of CTAB, the grain size of nickel deposit was reduced and the microhardness
of the nickel deposit was therefore improved. The hardness of the metal layer can be
promoted to 450 Hv when 300 ppm CTAB is added.
Single-Point Diamond Turning of Aspheric Mirror with Inner Reflecting Surfaces
Authors: Chon Kwon Su , Namba Yoshiharu , Yoon Kwon Ha
Published: March 2009

Grazing incidence optics used in soft X-ray microscopes require supersmooth surface and
highly accurate figure. We considered the fabrication of a Wolter type I mirror, one of grazing
incidence optics, with axial-symmetric inner reflecting surfaces using single-point diamond turning.
Electroless nickel was chosen as reflecting material Cutting conditions for machining the inner
reflecting surface were restricted because of long arm of a single-crystal diamond tool. The
machined Wolter type I mirror had approximately 270 nm P-V in figure error and 3 nm Ra in
surface roughness. The direct-machined Wolter type I mirror could be successfully used in a soft Xray
microscope based on laser-produced X-ray source.
A Novel Nanofluid Synthesis System for Preparation of Nanofluid
Authors: Chang Ho , Lin Shih Chieh
Published: March 2009

In this study, the author uses a novel nanofluid synthesis system to fabricate a TiO2 nanofluid. The improvement of the proposed nanofluid synthesis system focuses mainly on the pressure control system, coolant circulation system, parameter control system and the machine dimension of the original submerged arc nanofluid synthesis system. This helps to achieve an experimental machine with a fabrication condition to produce more stable and finer TiO2 nanofluids with a particle size of good reproducibility. Experiment is proceeded towards 15 sets of TiO2 nanofluid fabricated by the proposed system are tested under the experimental conditions of 250 V, 6 A of peak current, 2μs of discharge pause off time and 15 days of settling time. The experimental results show that the average Zeta potential of TiO2 nanofluids are -54.2 mv, and the difference between the data and the average value of each set is less than 7%. Furthermore, the average particle size is 45.3nm, and the difference between the data and the average value of each set is less than 6%. The fabricated TiO2 particles have an Anatase structure, and in the aspect of roundness measurement, the produced TiO2 has a good roundness of 0.3 nm. Experiment proves that the roundness of the fabricated TiO2 nanoparticles are much better than those fabricated by aerosol methods. Also, the fabricated nanofluid has a high suspension stability.
Application of Dynamic Optical Theory in Zoom System
Authors: Hu Yuan , Fu Yue Gang , Liu Zhi Ying , Gao Tian Yuan , Zhang Lei , Wang Zhi Jian
Published: March 2009

Dynamic optical is a theory which we can deduce the object-image conjugated rations of
optical system by researching motion group in optical system. It can unify various formula and
methods of optical system which have motion group. Zoom system is a typical dynamic optical
system. This paper will discuss how to apply the dynamic optical theory to zoom system design.
With dynamic optical theory, we can derive the image motion compensating formula and the trace
curve of the image motion compensating group. The cam can be fabricated according to
compensating curve, which can ensure the stabilization of image plane and keep imaging quality.
Moreover, a example of 30× zoom system is presented, which proves that the dynamic optical
theory has some practicability for zoom system design.
Modeling the Surface Roughness for Fine Turning of AISI304 Stainless Steel
Authors: Lin Wei Shin
Published: March 2009

High ductility, high strength, high work hardening rate and low thermal conductivity of stainless steels are the main factors that make their machinability difficult. In this study, determination of the optimum cutting condition has been aimed at when fine turning an AISI 304 austenitic stainless steel using ceramic cutting tools. The cutting speeds for the turning test were from 80 to 320 m / min, feed rates were from 0.04 to 0.10 mm / rev and the depth of cut was fixed at 0.1 mm. According to the test results, we can find that the values of surface roughness were decreased when the cutting speed was increasing, and decrease with the decrease of feed rate. But when the cutting speed was greater than 360 m / min, or the feed rate was smaller than 0.02 mm / rev，the surface roughness would be deteriorated because of the chatter phenomenon. In this paper, a polynomial network is adopted to construct a prediction model on surface roughness for fine turning of AISI304 austenitic stainless steel. The polynomial network is composed of a number of functional nodes. These functional nodes are self-organized to form an optimal network architecture by using a predicted square error (PSE) criterion. It is shown that the polynomial network can correctly correlate the input variables (cutting speed and feed rate) with the output variable (surface roughness). Based on the surface roughness prediction model constructed, the surface roughness of the workpiece can be predicted with reasonable accuracy if the turning conditions are given and it is also consistent with the experimental results very well.
Research on Quick Polishing of CVD Diamond Film
Authors: Chao Choung Lii , Fan Wei Haw , Chou Wen Chen , Chien Chun Yu , Lin Hung Yi , Duduch Jaime G.
Published: March 2009

Polycrystalline CVD diamond film possesses many advanced physical and mechanical properties which makes it a very important engineering material. However, high hardness value and extreme brittleness have made CVD diamond film a very difficult material to be machined by conventional grinding and polishing processes. In the present research, diamond wafers were pretreated with RIE in an attempt to weaken the top layer and pave the way for subsequent thermochemically polishing. It was found that the diamond grains were anisotropically etched and some high aspect ratio pillar-like micro-structures were formed during the RIE process. These micropillars are relatively easy to be ruptured and removed by the subsequent polishing process. The results showed that this method could effectively speed up the polishing of CVD diamond films.
Fabrication of Phase Mask for Optical Fiber Grating
Authors: Liu Quan , Wu Jian Hong , Fang Ling Ling , Li Chao Ming
Published: March 2009

A fused silica phase mask with the period of 1069nm, and ruled area 50×50mm2 has been fabricated by a new technique, which combines holographic-ion beam etching and reactive ion beam etching. This involves several steps: coating of substrates with controlled thickness of photoresist, formation of a grating mask by holograph interference exposure and development, and finally transferring etching of this mask into the fused silica substrate to form a permanent phase mask. Experimental measurements have shown that the zero order diffraction efficiency is less than 4% and the plus and minus first-order diffraction efficiency is more than 35%. Theoretical analysis has shown that these phase masks can be used for fabricating UV written Fiber Bragg Gratings.
Curvature Spectrum Correction in High Spectral Resolution Minitype Spectrometer
Authors: Sun Li Qun , Qiu Hong Yun , Huang Zhen Yu , Zhang En Yao , Tian Qian
Published: March 2009

The curvature spectrum causes the light energy within one spectral line cross several
CCD pixels in minitype spectrometer and decreases the resolution and sensitivity. To solve this
problem, a special vertical binning method for area image sensor is proposed. During the vertical
binning, the position of the electron package is moved in CCD horizon register. The energy center
of the same spectral line is always kept in the same electron package. Experiment has shown this
method as achievable and effective. The FWHM of Hg 576.960nm spectrum has been reduced to
0.21nm from 0.27nm and the peak intensity increased to 38513ADU from 28428ADU.
An Optical System for the Ball Grid Array Inspection and Measurement Using the Back-Propagation Neural Network Technology
Authors: Chen Shih Feng
Published: March 2009

In this study, the back-propagation neural network technology (BPN) is utilized to
identify the shape of the defective solder ball of ball grid array (BGA) so as to promote the accuracy
of the optical inspection and measurement. The two dimensional BGA optical inspecting system is
implemented by Visual Basic as the developing tool incorporated with the Halcon’s function which
is the database of the image processing on Windows operation system. For the development of the
processing procedure of the automatic optical inspecting system, the precise geometrical
information of the solder ball is evaluated by the sub-pixel method to identify the shape of solder
ball and its location which are acquired to classify the defects of solder ball including the ball offset,
the ball over scale, the ball absence, and the ball shape under the BGA board is offset and rotated at
any angle. From the experimental results, the back-propagation neural network technology is
proved to properly identify and classify the shape defects, especially for the ball deformation and
the ball bridging of the solder ball which can achieve and contribute the requirements for the
automatic inspection and the high identification efficiency.
Application of Adaptive Mesh and ALE Method in Simulation of Extrusion of Aluminum Alloys
Authors: Kayser T. , Parvizian Farhad , Hortig C. , Svendsen Bob
Published: March 2009

The purpose of this work is the modeling and simulation of the material behavior of aluminum
alloys during extrusion processes. In particular, attention is focused here on aluminum alloys
of the 6000 series (Al-Mg-Si) and 7000 series (Al-Zn-Mg). The material behavior of these alloys
during extrusion is governed mainly by dynamic recovery and static recrystallization during cooling.
The current material model is based on the role of energy stored in the material during deformation,
as it acts as the driving force for microstructural development. The concept of internal variables is
used to describe state quantities such as dislocation density, average grain size and average grain
orientation. The focus of the current paper is on some of the numerical aspects of the extrusion
process simulation such as contact problems and adaptive mesh refinement which should be considered
in order to obtain more accurate and robust results.
Creep and Fatigue Damage in Hot Work Tools Steels during Copper and Aluminium Extrusion
Authors: Sommitsch Christof , Wlanis Thomas , Hatzenbichler Thomas , Redl Christian
Published: March 2009

During hot extrusion, tools experience cyclic thermo-mechanical loads that can lead to
materials degradation and failure. For a process optimization and study of the occurring damage
mechanisms, the finite element method (FEM) is an appropriate means. Local inelastic strains result
from the interaction of the applied temperature and stress loading and can be computed by suitable
inelastic constitutive equations. Stress amplitudes and dwell times during extrusion result in creepfatigue
damage. A lifetime consumption model sums increments of a damage variable over time and
defines materials failure as the accumulation of the resulting damage variable to a critical value. The
predominant failure mechanism, i.e. creep or fatigue, can be found by the investigation of the
damage rate over several cycles. A comparison of both a creep dominated (copper extrusion) and a
fatigue controlled (aluminium extrusion) lifetime consumption in an extrusion die is shown with the
hot work tool steel Böhler W300 ISOBLOC in comparison with W400 VMR (both ~ EN 1.2343).
Different Possibilities of Process Analysis in Cold Extrusion
Authors: Plancak M. , Barisic Branimir , Grizelj Branko
Published: March 2009

Cold extrusion is a technology which offers a number of advantages when compared to other manufacturing technologies. High mechanical properties of extruded component, short production time as well as significant cost effectiveness which can be achieved by implementation of this technology are the main characteristics of cold extrusion process. In order to design the complete extrusion process in optimal way it is crucial to know the main process parameters such as load, die pressure, stress and strain distribution within deformation zone etc. There is a number of methods for the analysis of cold extrusion processes. Current paper gives the insight into the possibilities of process analysis in three different cases of cold extrusion. Radial extrusion of gear like elements has been analyzed theoretically (Upper Bound method), numerically by FE simulation and experimentally. Die stressing has been measured by special device (pin load cell) in the process of forward extrusion. Third analyzed process was backward extrusion with profiled punch. In this process loading characteristics as well as some of the mechanical properties of extruded component were obtained experimentally.
Evaluation of the Microstructure of 3D-Cf/SiC Composites Fabricated by Precursor Infiltration and Pyrolysis
Authors: Li Wei , Chen Zhao Hui
Published: March 2009

The microstructure and its evolution of 3D-Cf/SiC composites derived from organic precursor
are studied by using scanning electronic microscopy, mercury intrusion porosimetry, isothermal N2
sorption and bubble point method, etc. As the results shown, MIP is preferable to N2 sorption for the
characterization of pore size distribution (PSD) because of its wider effective probing ranges. The typical
porosity of fabricated 3D-Cf/SiC composites is 10-15vol.%, and all the pores distribute in a quite wide
size ranging from some dozens of nanometers to hundreds of microns and can be divided into three
groups, according to their sizes, contents and locations: the inter-bundle macro-pores/paths, the
intra-bundle pores and the micro-pores/cracks around the interfaces or in the matrixes. The
macro-pores/paths constitute a porous network, which is partially open throughout the composites.
Preparation and Properties of 2D Carbon Cloth Reinforced Ultra-High Temperature Ceramic Matrix Composites
Authors: Zhou Yong Lian , Hu Hai Feng , Zhang Yu Di , Wang Qi Kun , Zhang Chang Rui
Published: March 2009

In this paper the preparation of carbon fiber reinforced ultra-high temperature ceramic matrix composites was reported. Polymer infiltration and pyrolysis process was used to prepare 2D C/TaC-SiC, C/NbC-SiC, and C/ZrC-SiC composites. The fracture strengths of all the samples were around 300MPa and toughness around 10MPa-m1/2. Standard oxyacetylene torch tests (>3000°C, 30s) showed that the minimum ablative rate of 2D C/SiC-ZrC was as low as 0.026 mm/s, much smaller than that of 2D C/SiC composites (0.088mm/s).
Effects of Mo(Ni) on Valence Electron Structures of TiC/Fe Cermets
Authors: Zou Zheng Guang , Wu Yi , Long Fei , Xu Wen Wu , Yao Dong Ye
Published: March 2009

Based on the empirical electron theory (EET) of solids and molecules, the valence electron structures (VESs) of TiC-Mo(Ni)-Fe system were calculated by building proper structure model. The results indicate that additives of Mo and Ni improve the interface conjunction factors of the cermets in different ways. By adding Mo, the VESs of the ceramic phase are improved for the formation of the rim phase (Ti1-xMox)C, which leads to the enhancement of the interface conjunction, while the improvement of the VESs on metal phase by adding Ni is due to the formation of the Fe100-yNiy. Mo and Ni additives increase the interface electron density of cermets, that is, the adding of the Mo and Ni enhance the overlapping grade of the electron cloud on interface and increase the binding energy of the interface, which is propitious to the wettability. The best wettability was found at x=0.5 or y=30.
Hydration Resistance of Al/AlN Bonded Corundum Based Multiphase Material
Authors: Fang Bin Xiang , Zhu Bo Quan , Zhang Wen Jie , Li Xue Dong , Fan Zheng Yun
Published: March 2009

The Al/AlN bonded corundum based multiphase material was prepared by raw materials of fused alumina and metallic aluminum powder by in situ reaction at 1100°C for 3h in N2 . The XRD analysis showed that the mineral phases of prepared material are corundum, metallic aluminum and AlN respectively. The SEM investigation revealed that both tetragonal whiskers and hexagon powders of AlN were formed. The results of hydration tests indicated that the rate of weight gain and pulverization of the material were negligible and the ratio of residual crushing strength was kept at a high level. The XRD patterns of samples after hydration tests identified that the AlN phase still remained although a small amount of AlOOH and Al(OH)3 was formed due to the hydration of AlN. It is believed that the limited hydration of AlN should be contributed to the dissolution of O element to AlN. The hydration mechanism of AlN was discussed.
In Vitro Dissolution Behavior of Biphasic Tricalcium Phosphate Composite Powders Composed of α-Tricalcium Phosphate and β-Tricalcium Phosphate
Authors: Li Yan Bao , Li Dong Xu , Weng Wen Jian
Published: March 2009

Biphasic tricalcium phosphate (BTCP) powders composed of α-tricalcium phosphate (α-TCP)
and β-tricalcium phosphate (β-TCP) were prepared using amorphous calcium phosphate (ACP) precursor
after heat treatment at 800oC. The in vitro dissolution behavior of the powders was examined after soaked
in 0.1M NaAc-HAc buffer solution for different times. It was revealed that the Ca2+ and PO4
3-
concentration, and pH value of the BTCP-soaked solution are higher than those of the α-TCP- and
β-TCP-soaked solutions. The dissolution behavior of BTCP powders was explained. The specific
dissolution behavior of BTCP powders can widen the biodegradation range of calcium phosphate family.
Study on Porous Titanium Biomedical Materials
Authors: Li Mu Qin , Yang Han Song , Qu Li Jie , Zhuang Ming Hui
Published: March 2009

The bioactivity of porous titanium is poor. Alkali treatment and heat treatment were used in
porous titanium to induce apatite biocoatings on the surface of porous titanium and improve the
bioactivity of porous titanium. The results indicate that grass-blade fibre Na2TiO3 and amorphous rutile
form on alkali and heat treatment samples and (102) plane Ti disappeared. Octacalcium phosphate (OCP)
and Hydroxyapatite (HA) were found on the surface of samples in simulation body fluid (SBF) for 2w.
The intensity of OCP and HA increased with time of samples in vivo increased. Ti-OH formed on the
surface of the gel was explained by the point of view of negative and positive ion exchange. The
mechanism of formation of OCP and HA induced by Na2TiO3 and TiO2 gel was studied.
Properties of Al2O3-TiO2 Coating Prepared by Plasma Spraying with an Internally-Fed Powder System
Authors: Zhou Feng , Fu Ying Qing , Gao Yang
Published: March 2009

Alumina-titania (60: 40 by weight) coatings were prepared by low power plasma thermal
spraying with two types of plasma spray systems: internally-fed and externally-fed powder system. The
coatings were investigated by many techniques, respectively X-ray diffraction (XRD), scanning electron
microscopy (SEM) and micro-hardness tester. It was found that the thickness of coatings by low power
plasma spray with an internally-fed powder system is higher than that of the coatings with an
externally-fed powder system. The internally-fed powder system not only decreases the loss of powder
but also increases the deposition efficiency for more than 80%. To better qualify the characteristics of
these coatings prepared from spray-dried powders, microhardness was also studied.
Mechanical Properties of Nanostructured Zirconia Coatings Fabricated by Air Plasma Spraying
Authors: Zhou Hong , Wang Jun , He Bo , Li Fei , Ma Jing , Sun Bao De
Published: March 2009

Nanostructured coatings are experiencing a rapid development in recent years due to their
potential applications in a wide variety of technological areas. In order to improve the properties of
thermal barrier coatings, nanostructured 8 wt% yttria partial stabilized zirconia coatings were deposited
by air plasma spraying with reconstituted nanoparticles on titanium alloy substrates. For comparison, the
conventional counterparts were also fabricated. Their microstructures were investigated by using
transmission electron micrograph and scanning electron micrograph. Their mechanical behaviors were
evaluated via Vickers microhardness test and tensile test. The results indicate that the nanostructured
zirconia coatings with original nanostructure and columnar grains have higher microhardness and adhesive
strength than the conventional counterparts. Both the nanostructured coating and the conventional
coating exhibit a bimodal distribution of microhardness values, which are analyzed via Weibull statistics.
This phenomenon is attributed to the presence of molten and non-molten parts in the coatings.
Reactive Electric Spark Deposition of Ti(CN)–Based Ceramics Coating on Titanium Alloy Substrate
Authors: Hao Jian Jun , Pu Zhi Guo , Liu Hong Jie , Zhao Jian Guo
Published: March 2009

Ti(CN) -based ceramics coating was deposited on TC4 titanium alloy substrate using the
home- made reactive electric spark deposition system, which is under nitrogen-sealed atmosphere and
using the graphite electrode. It was showed that: (1) the single-pulse deposition zone presents irregular
spattering shape and the phase of coatings was made up of TiC0.51N0.12 spherocrystal and dendritic crystal,
Ti0.80V0.20 and C, (2) metallurgical bond between coating and substrate is realized, (3) the Ti(CN) ceramic
particle, whose average grain size is 626nm, distributes dispersively among the coating and is in-situ
synthesized by the reaction among titanium from the substrate, carbon from the graphite electrode and
nitrogen from the shielding nitrogen gas.