bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of an Equivalent Circuit Model for Ionic Polymer-Metal Composite (IPMC) Bending Actuator Loaded With Multiwalled Carbon Nanotube (M-CNT)
Authors: Lee Deuk Yong , Kim Kwang Jin , Heo Seok , Lee Myung Hyun , Kim Bae Yeon
Published: March 2009

Biomimetic actuators that can produce soft-actuation but large force generation capability are of interest. NafionTM, an effective ionomeric material from DuPont, has been shown to produce large deformation under low electric fields (<10V/mm). In this effort, multi-walled carbon nanotube (M-CNT)/NafionTM nanocomposites were prepared by casting in order to investigate the effect of M-CNT loading in the range of 0 to 7 wt% on electromechanical properties of the MCNT/ NafionTM nanocomposites. The measured elastic modulus and actuation force of the MCNT/ NafionTM nanocomposites are drastically different, showing larger elastic modulus and improved electromechanical coupling, from the one without M-CNT. In this work, we attempted to incorporate an equivalent circuit analysis to address the effect of capacitance and resistance of such M-CNT/NafionTM nanocomposites that would differ from conventional IPMCs.
Correlating Electrospray Characteristics with Surface Morphology of Calcium Phosphate Coatings Deposited Using Electrostatic Spray Deposition (ESD)
Authors: Leeuwenburgh Sander C.G. , Heine M.C. , Wolke Joop G.C. , Pratsinis Sotiris E. , Schoonman J. , Jansen John A.
Published: March 2009

In situ measurements of electrospray droplet sizes and velocities were performed by
Phase Doppler Anemometry during Electrostatic Spray Deposition (ESD) of calcium phosphate (CaP) coatings. Numerous processing parameters were varied (nozzle-to-substrate distance, deposition temperature, nozzle geometry, and composition of the precursor solution), whereafter the
morphological characteristics of these ESD-derived CaP coatings were correlated with measured droplet characteristics. Equal droplet sizes and velocities were measured for nozzle-to-substrate distances up to 40 mm and deposition temperatures up to 400 °C, indicating that electrospray droplets did not shrink at all during droplet flight using an involatile solvent butyl carbitol with a high boiling point (Tb = 231 °C). Nevertheless, coatings with considerably different surface
morphologies were obtained under these conditions, varying from microporous structures with coalesced pore walls to morphologies revealing isolated rings on top of dense or grainy underlayers. The chemical composition of the precursor solutions and the mixing characteristics of the calcium and phosphate precursor components strongly influenced the initial droplet sizes, precipitation kinetics of the CaP solute, and subsequent coating morphology. Unique, reticular coating morphologies were deposited at a deposition rate of 3.2 µm/hour, which have a graded structure
consisting of a dense underlayer, a submicron-porous intermediate layer, and a roughened toplayer revealing droplet-derived features such as isolated rings or coalesced, hollow surface pits.
Growth Behaviour of Rat Bone Marrow (RBM) Cells on RF Magnetron Sputtered Hydroxyapatite and Dicalcium Pyrophosphate Coatings
Authors: Wolke Joop G.C. , Yan Yong Gang , Li Yu Bao , Jansen John A.
Published: March 2009

The aim of this study was to evaluate the osteogenic properties of magnetron sputtered dicalcium pyrophosphate (DCPP) and hydroxylapatite (HA) coatings. Therefore, DCPP and HA coatings were deposited on grit-blasted titanium discs. The substrates were used as-prepared or received an
additional heat treatment with changed the amorphous coating structure to a crystalline structure. Subsequently, rat bone marrow stromal cells were cultured for 1-24 days on the various substrates. DNA and alkaline phosphatase activity was determined after 1, 3, 5, 8 and 12 days of incubation. Osteocalcin expression was evaluated after 8, 12, 16 and 24 days of incubation. Scanning electron
microscopical analysis of cell morphology and coating characteristics was done after 8 and 16 days of incubation. All assays were done in duplicate and in each assay all specimens were present in fourfold. Results demonstrated that the cells did not proliferate and differentiate on all amorphous coatings. SEM revealed that the amorphous coatings showed significant dissolution. On the crystalline DCPP and HA coatings an increase in DNA and alkaline phosphatase activity was seen
starting at day 8 of incubation. Osteocalcin expression on the crystalline coatings started to increase at day 16 of incubation. SEM showed that the growth and differentiation of the cells was associated with extensive collage fiber formation and surface mineralization in the form of globular accretions. Further, statistical testing revealed that proliferation and differentiation of the rat bone marrow
stromal cells started significantly earlier on the crystalline HA coatings than on the crystalline DCPP coatings. These results demonstrate that the rat bone marrow stromal cells proliferated and differentiated only on crystalline magnetron sputtered DCPP as well as HA coatings, which warrants the further in vivo analysis of the bone healing supporting properties of these coatings.
Biomimetic Ceramic Surfaces Produced by Thermal Spraying Nanostructured Titania: A Coating Alternative to Hydroxyapatite on Orthopedic Implants?
Authors: Marple Basil R. , Lima R.S. , Li H. , Khor Khiam Aik
Published: March 2009

There is an ongoing effort to improve the quality and performance of orthopedic implants. Part of this work involves the development of coatings suitable for use in the human body and having properties and bio-performance characteristics better than those of existing materials. The present study focused on developing thermal spray titania coatings engineered to have a bimodal structure consisting of a major fraction of micron scale dimensions within which were dispersed zones of nanostructured material. The coatings were found to exhibit much stronger adhesion to Ti-6Al-4V substrates than conventional hydroxyapatite coatings and to possess excellent crack propagation resistance characteristics. Cell culture studies indicated that human osteoblasts attached and proliferated well on the coating surface. The surface nano-features and nanostructured zones in the coating are believed to play an important role in the improved bonding, mechanical properties and bio-performance.
Electrophoretic Deposition of Nacre Coatings on Titanium Substrates
Authors: Zhou Hai Fang , Wang Xiao Xiang , Wang Ri Zhi
Published: March 2009

Nacre powder suspensions in alcohol added with acetic acid (Suspension I) or calcium chloride (Suspension II) were prepared. Titanium substrates were coated with nacre powder by EPD in the suspensions. The result shows that Suspension II is more stable than Suspension I, and deposition rate in Suspension II is much higher than that in Suspension I. XRD and FTIR results show that the nacre coatings exhibit the same characteristics as the raw nacre powder. SEM
morphologies show that uniform coatings are achieved. Scratch test shows that bonding strength of coatings from Suspension I is much higher than that of Suspension II. The higher bonding strength from Suspension I was confirmed to be closely related to the concurrent deposition of organic molecules dissolved in the suspension.
Preparation of Poly(Lactic Acid) Hybrid Membranes Containing Silica
Authors: Maeda Hirotaka , Kasuga Toshihiro , Hench Larry L.
Published: March 2009

A novel poly(lactic acid) (PLA)/calcium carbonates hybrid membrane containing silica was prepared using aminopropyltriethoxysilane (APTES) for biodegradable bone guided regeneration. Carboxy groups in PLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The silica-hybridized PLA was an amorphous phase. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3 d of soaking in
simulated body fluid (SBF). After soaking the membrane in SBF, almost no Si was present in SBF. X-ray energy dispersive spectroscopy showed the HCA layer includes Si with Ca and P. A result of osteoblast-like cellular proliferation on the membrane showed no cell-toxicity.
Expression of Bioactivity and Biocompatibility Testing of Bioactive Glass Modified Zinc Phosphate Luting Cement
Authors: Kontonasaki Eleana , Papazisis K. , Papadopoulou Lambrini , Zorba T. , Kortsaris A. , Garefis P. , Paraskevopoulos Konstantinos M. , Koidis Petros
Published: March 2009

The bioactivity and biocompatibility of a zinc phosphate luting cement (HARVARD,
Richter & Hoffmann, Dental-GmbH, Berlin) which was modified by Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials), was evaluated in vitro with human lung fibroblasts (MRC-5), baby hamster kidney fibroblasts (BHK) and rat pulp cells (RPC) by XTT and BrdU assays. A thin Ca-P layer was grown on the surface of Bioglass®-modified zinc phosphate
cement specimens after immersion in SBF for 7 days and remained constant after 16 days immersion time. The incorporation of Bioglass® powder in zinc phosphate specimens resulted in equal or increased cell attachment and activity for almost all cell lines examined without any apparent impact on mechanical or physicochemical properties of the cement, although this needs further documentation. The combination of these two methods in determining the biocompatibility
of Bioglass®-modified zinc phosphate cements showed that cells not only attached well on modified specimens but were actively synthesizing DNA after 72h of incubation.
Influence of Newly Developed Resin and MMA Resin on Mouse Fibroblasts Cellular Viability
Authors: Jinno S. , Suzuki T. , Ishikawa A. , Hayashi T. , Deguchi M. , Ito M. , Nakano K. , Kawai Takahiro , Noguchi T.
Published: March 2009

The aim of this study is evaluate to the cellular viability of elution from the newly
developed resin and Osteobond® in vitro. The basis of the newly developed resin are methacryloyloxyethyl methyl succinate and 1,6-Hexanediol dimethacrylate. The basis of Osteobond is methyl methacrylate. The concentrations of basis in each elution were determined by high-performance liquid chromatography (HPLC). Cellular viabilities of L-929 mouse fibroblasts were evaluated by direct cells counting, and then, each IC50 value was calculated. Moreover, patterns of cell death were analyzed using annexin V/propidium iodide staining with the
phase-contrast microscope and flow cytometry. The concentration of Osteobond elution was 2.16 mM of MMA, and the newly developed resin elution was 1.02 mM of TA and 1.87 x 10-2 mM of HX. Until 72 hours of incubation, treatment with each elution impaired the viability of L-929 cells in a dose-dependent manner. IC50 value of Osteobond was 6.48 x 10-4 mM of MMA. However, IC50 of the newly developed resin was not calculated. Treatment with Osteobond elution showed
more necrotic cells than with the newly developed resin elution. In conclusion, the results demonstrated much more excellent cellular viability of the newly developed resin than that of MMA resin. Thus, it is suggested that the newly developed resin will be more useful as an implantation material for dentistry and orthopaedics.
In Vitro Mechanical Properties of a Calcium Silicate Based Bone Void Filler
Authors: Engqvist Hakan , Edlund S. , Gómez-Ortega Gunilla , Lööf Jesper , Hermansson Leif
Published: March 2009

The objective of the paper is to investigate the mechanical and the handling properties of a novel injectable bone void filler based on calcium silicate.
The orthopaedic cement based on calcium silicate was compared to a calcium phosphate cement, Norian SRS from Syntes Stratec, with regard to the working (ejection through 14 G needle) and setting time (Gillmore needles), Young’s modulus and the flexural (ASTM F-394) and compressive (ISO 9917) strength after storage in phosphate buffer saline at body temperature for
time points from 1h up to 16 weeks. The calcium silicate cement is composed of a calcium silicate powder (grain size below 20 µm) that is mixed with a liquid (water and CaCl2) into a paste using a spatula and a mixing cup. The water to cement ratio used was about 0.5. The calcium silicate had a working time of 15 minutes and a setting time of 17 minutes compared to 5 and 10 minutes respectively for the calcium phosphate cement. The compressive strength was considerably higher for the calcium silicate cement (>100 MPa) compared to the
calcium phosphate cement (>40 MPa). Regarding the flexural strength the calcium silicate cement had high values for up to 1 week (> 40 MPa) but it decreased to 25 MPa after 16 weeks. The phosphate cement had a constant flexural strength of about 25 MPa. The results show that calcium silicate cement has the mechanical and handling potential to be used as high strength bone void filler.
Effect of Bioactive Glass/Cement Weight Ratio on Bioactivity and Biocompatibility of a Bioactive Glass Modified Glass Ionomer Cement
Authors: Kontonasaki Eleana , Papadopoulou Lambrini , Zorba T. , Siarampi E. , Papazisis K. , Kortsaris A. , Paraskevopoulos Konstantinos M. , Koidis Petros
Published: March 2009

The bioactivity of a glass ionomer luting cement (Ketac®-cem, ESPE, Germany), which was modified by Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials) in different bioglass/powder weight ratios, and the biocompatibility of the produced mixtures were evaluated in this study using different cell lines. The incorporation of Bioglass® in the cement structure resulted in the formation of sparsely located biological apatite aggregations. However,
although Bioglass® incorporation seemed to enhance cell proliferation, the materials became eventually brittle and highly soluble depending on Bioglass® amount.
Porous Apatite Carrier Prepared by Hydrothermal Method
Authors: Kawachi Giichiro , Sasaki Shuji , Nakahara Kazuhiko , Ishida Emile Hideki , Ioku Koji
Published: March 2009

Porous apatite carrier with high selectivity of adsorption was prepared by using hydrothermal method. α-TCP as the starting material was changed into hydroxyapatite at the temperature above 120 °C for the period over 3 h under saturated vapor pressure. Porous apatite carriers were composed of rod-shaped crystals with non-stoichiometric hydroxyapatite composition. Since HA crystals had rod like shape, the area of a-surface was larger than that of c-surface. This carrier had higher selectivity for bovine serum albumin (acidic protein) than lysozyme chloride (basic protein). This material must be suitable as scaffold for cultured bone, for bone graft material and for drug delivery system (DDS).
Hyperstructured Hydroxyapatite Ceramics as a Carrier for Cell and Protein
Authors: Yokogawa Yoshiyuki , Seelan Sindhu , Zhang Yin
Published: March 2009

The preparation of hyperstructured hydroxyapatite (HAp) ceramics is reported. Mesoporous silica with nano size pore was coated on the bi-modal type porous HAp ceramics with pore size 100-200 µm and 1-2 µm. The mesoporous silica coating was done using two different procedures and the ceramics were characterized by XRD, N2 Sorption, SEM/EDX, and TEM. The results clearly showed the formation of mesoporous coating on the large pores of parent HAp ceramics. SEM images reveal that the mesoporous coatings consists of almost spherical particles with relatively uniform sizes of ~1 µm. Protein adsorption and release behavior on these mesoporous coated HAp ceramics was evaluated using UV-VIS spectrometry. The large pores are suitable for cell immobilization, and the mesopores several nm in size were found to enhance protein encapsulation ability.
Statistical Characteristics of Inter-Particle/Void Distance for Particulate Composites
Authors: Kim Nam Ho , Kim Ho Sung
Published: March 2009

Two dimensional statistical characteristics of inter particle/void distance (ID) for various particle/void and dispersion types are studied in relation with toughening of plastics using computer generated three dimensional models. Particle/void size groups adopted were of log-normal distribution. Particles/voids were dispersed at uniform-random. It was found that IDs are (a) of approximately Gaussian distribution but; (b) not of Gaussian distribution for particle/void sizes of
bimodal log-normal distribution (created by mixing of two groups of articles/voids). It was also found that the degree of ID uniformity, which can be represented by the inverse of the coefficient of variation, for a single group of log-normally sized particles/voids is not sensitive to standard deviation of particle/void size.
Mixing effect on ID characteristics using two groups of log-normally distributed particles/voids with similar mean particle/void diameters was simulated. It was found that, when a significant amount (36 vol %) of particles/voids of a small mean and standard deviation of ID, was mixed with a group of particles/voids of a large mean and standard deviation of ID, mean and standard deviation of ID for the mixture were not substantially lower than those of the group of particles/voids of the large mean and standard deviation of ID. It was also found that the degree of ID uniformity for the mixture of the two groups were lower than those of individual groups,
indicating that the mixing has deleterious effect on toughening.
On the Homogenization Concepts and Macroscopic Properties of Orthotropic Composites with Non-Symmetrically Shaped Inclusions
Authors: Yang Qing Sheng , Qin Qing Hua
Published: March 2009

Homogenization is an important analysis approach of composite materials with structural hierarchy and can give the prediction of macroscopic properties of the composites. There are many homogenization theories and methods. The present paper discusses applications of some homogenization approaches including both direct and mathematical homogenizations for the analysis of anisotropic composites with periodic microstructures. The macroscopic properties of the
composite are predicted by the direct homogenization and the mathematical homogenisation method. The periodic boundary conditions of a representative volume element are implemented by a transformation method of the degrees of freedom. The numerical results are demonstrated for two model composites. The study shows that these two homogenization methods gave the same results
for the macroscopic elastic stiffness of the composites although they are of different mathematical forms and different operation procedures.
Factors that Affect Fibrillation of the Liquid Crystalline Polymer (LCP)Phase in an Injection Moulded Polycarbonate / LCP Blend
Authors: Tan Lay Poh , Yue Chee Yoon , Tam K.C. , Lam Yee Cheong , Hu X.
Published: March 2009

The effects of compatibilization and mould geometry on the fibrillation of liquid crystalline polymer were investigated in this study. The blend is composed of polycarbonate (PC) and LC5000, a thermotropic liquid crystalline polymer consisting of 80/20 wt% of hydroxybenzoic acid and poly(terephthalate). The effect of compatibilization was investigated by studying the morphological properties of injection moulded plaques and significant enhancement in the fibrillation of LCP was observed in the moulded samples after addition of the compatibilizer. The effect of mould geometry was studied by comparing results obtained from three types of specimens, namely, specimens cut from large rectangular plaques, moulded rectangular bar specimens and molded dog-bone specimens. It was found that mould geometry had a direct influence on the magnitude of the elongational and shear stresses in the melt during molding and thus affected the degree of LCP fibrillation. Moreover, it was observed that the constriction at the “neck” of the dogbone geometry actually facilitated development of LCP fibre in the blend by increasing shear stress during moulding and promoting LCP fibre coalescence.
A Cross-Scale Characterization of Interface Properties between Carbon Nanotubes and Polymer Matrix
Authors: Mylvaganam Kausala , Zhang Liang Chi
Published: March 2009

This paper discusses the methods of promoting covalent bonds between polymer and carbon nanotubes to make high performance composites. Such methods involve attachment of chemical moieties (i.e. functional groups) to the sidewalls of carbon nanotubes, introduction of mechanical deformation on nanotubes, or generation of radicals on the polymer chains using free radical generators. The implementation of the latter method is demonstrated at both quantum mechanics and molecular dynamics levels.
Preparation of Nano-Silica/Polypropylene Composites Using Reactive Compatibilization
Authors: Friedrich Klaus , Rong Min Zhi , Zhang Ming Qiu , Ruan Wen Hong
Published: March 2009

Nano-sized silica particles were pre-grafted with poly(glycidyl methacrylate) (PGMA) by solution free-radical polymerization. When these grafted silica nanoparticles were melt compounded with polypropylene (PP), reactive compatibilization effect was perceived due to the chemical bonding between the grafted PGMA and amine functionalized PP, which led to a significant increase of tensile strength and notch impact strength of PP at rather low filler content.
Accordingly, compatibility of each kind of the functionalized PP with grafted SiO2 nanoparticles was evaluated through investigating the mechanical properties, crystallization behavior and rheological performance of the composites. The results show that the reactive compatibilization is capable of providing stronger interfacial adhesion.
Evaluation of Moisture Content in Concrete with Microwave
Authors: Wang Xiao Ming , Teo Yinghao , Chiu Wing K. , Foliente Greg
Published: March 2009

Generally, any chemical or physical change in a material may cause variation in its
permittivity and permeability. The propagation of microwave through the material can be affected by these variation in properties. The analysis of microwave propagation through materials may therefore provide a means for condition monitoring. This paper utilizes a one-dimensional scenario, demonstrating the feasibility to link measurable reflection and transmission coefficients of microwave to concrete permittivity and permeability, which are essentially associated with water
content in concrete. As a result, water content can then be monitored through the measurement of these coefficients. The study also demonstrates the feasibility of using the same technique to estimate the thickness of the concrete that microwave propagates through.
Thermal Effects of Cracked Piezoelectric Materials under Cycling Electric-Loading
Authors: Du Ning Ning , Yu Shou Wen
Published: March 2009

It is still an open problem how the thermal effect influences the fracture behavior of
piezoelectric materials especially under cycling electrical loading. Experimental observations have found that the fracture toughness of piezoelectric solids under electric loading may be greatly different from that under mechanical loading. A pronounced rise of temperature may be caused either by mechanical or by electric loading. In this paper, the thermal effects and energy dissipation mechanism in cracked piezoelectric materials under cyclic-electric-loading have been studied. The
temperature rise is derived under the assumption of decoupling between thermal and
electromechanical fields and the influences of frequency and the shape of electric wave on the temperature rise are quantitatively analyzed.
Functionally Graded Materials with Periodic Cracks Subjected to Transient Loading
Authors: Han Jie Cai , Wang Bao Lin
Published: March 2009

A periodic array of cracks in a functionally graded material under transient mechanical loading is investigated. Anti-plane shear loading condition is considered. A singular integral equation is derived, in which the crack surface displacement is the unknown function. Numerical results are obtained to illustrate the variations of the stress intensity factors as a function of the crack periodicity for different values of the material nonhomogeneity, either at the transient state or at the steady state. The material non-homogeneity can increase or reduce the stress intensity factors.
Comparing with the single crack solution, it can be shown that multiple cracking can reduce the stress intensity factor significantly.
Notch Effects in Tensile Behavior of AM60 Magnesium Alloys
Authors: Yan Cheng , Ma W. , Burg V. , Mai Yiu Wing , Geers M.G.D.
Published: March 2009

The deformation and failure behavior of an AM60 magnesium alloy was investigated
using tensile test on circumferentially notched specimens with different notch radii. The strain and stress triaxiality corresponding to the failure point were evaluated using both analytical and finite element analyses. Combining with systematical observations of the fracture surfaces, it is concluded that deformation and failure of AM60 magnesium alloy are notch (constraint) sensitive. The failure mechanisms change from ductile tearing to quasi cleavage with the increase of constraint.
Hybrid Special Finite Element Method for Bi-Material Crack
Authors: Yang Chun Hui , Zhang Y.X. , Huh Hoon
Published: March 2009

In the paper, two novel 2-D hybrid special finite elements each containing an interfacial edge crack, which lies along or vertical to the interface between two materials, are developed. These proposed elements can assure the high precision especially in the vicinity of crack tip and provide a better description of its singularity with only one hybrid element surrounding one interfacial crack, thus, the numerical modeling of fracture analysis on bi-material crack can be greatly simplified.
Numerical examples are provided to demonstrate the validity and versatility of the proposed method.
Fabrication and Characterization of Nanocomposites Reinforced by Carbon Nanotubes-(2)Testing of Mechanical Properties
Authors: Tai Nyan Hwa , Yeh Meng Kao , Liu Jia Hau , Yang Chien Hsin
Published: March 2009

Composites of phenolic resin reinforced by the multi-walled carbon nanotubes (MWCNTs) were fabricated and its mechanical properties were measured. The MWCNTs were synthesized by the floating catalyst method in a thermal chemical vapor deposition chamber. Benzene, hydrogen, ferrocene, and thiophene were used as carbon source, carrier gas, catalyst, and growth promoter, respectively. The nano-composites were made by the melt mixing and the resin infiltration methods. Tensile strength, Poisson’s ratio, and modulus were measured and the morphologies on the fracture surface were examined by the field emission scanning electron microscope (FESEM). The microstructure of the synthesized MWCNTs reinforced nano-composites was examined by FESEM. The influences of MWCNTs amounts on the mechanical properties of the nano-composites were discussed.
Aluminum Borate Whiskers Growing by Compensation of TiB2
Authors: Zhang Dong Ming , Li You Jun , Zhang Lian Meng , Guo Jing Kun
Published: March 2009

Aluminum borate whiskers with TiB2 as borate source were prepared in this paper. The phase transformation process was analyzed by XRD and TG-DSC. The results indicate that TiB2 was decomposed into TiO2 and B2O3 in the calcining process in the active [O] atmosphere. 2Al2O3.B2O3 was formed in the lower temperature with reaction of Al2O3 and B2O3, while 9Al2O3.2B2O3 whiskers were grown by compensation of 2Al2O3.B2O3 at higher temperature (above 1050oC)
Controlled Nano-Oxide Layer Coating on Fine Particles with Multiple Optical-Electrical Functions
Authors: Wei Wen Cheng J. , Yu B.Y. , Li J.F. , Chen C.S.
Published: March 2009

SiO2 core/TiO2 shell composite particles were synthesized by four different
heterogeneous coagulation techniques. The configurations of the composite particles and the microstructure of assembly were characterized by SEM and TEM. The colloidal stability of nano-particles was also computer-simulated by a discrete element method (DEM) in consideration of Brownian motion occurring on the nano-particles. The results indicated that uniform adsorption of the fine particle absolutely needed fine tuning of surface charging conditions and processing steps.
Influence of Stackers of Particles on Piezoelectricity of 0-3 Type Piezo-Composite
Authors: Luo D.B. , Liu H.X. , Ouyang Shi Xi
Published: March 2009

Piezoelectricity of composite was simulated by employing Dilute Model and Limit Unit
method. The analogizing results recommend that the particle stackers influence the properties of piezo-composite. While fabricating piezo-composite, particles stack different with different routine. For thermo-pressing proceeding, stackers trend to take on higher D33 than that processing from forging-membrane.
Texturation of YBa2Cu3O7-δ Thick Films by Electrophoretic Deposition under Magnetic Field
Authors: Dusoulier L. , Denis S. , Nutal N. , Henrist Catherine , Vanderheyden B. , Vanderbemden P. , Rulmont André , Dirickx M. , Ausloos Marcel , Cloots Rudi , Vertruyen Bénédicte
Published: March 2009

YBa2Cu3O7-δ coatings were deposited by electrophoretic deposition (EPD) onto Ni substrates. Particles of different sizes and shapes were used in order to study the influence of the powder microstructure on the film density. Texturation of the thick films was induced by application of a magnetic field during the electrophoretic deposition. X-ray diffraction analysis has clearly shown preferred c-axis alignment of the YBa2Cu3O7-δ films along the direction normal to the substrate surface. Scanning electron microscopy and optical polarised light microscopy were used to characterise the microstructure of the coatings, revealing a nonrandom platelets organisation.
EPD-Sintering of Hydroxyapatite, Porcelain and Wollastonite on 316L Stainless Steel
Authors: Vargas Gregorio , Mondragón P. , García-Ruiz Georgina , Rodríguez Hugo H. , Chávez-Valdez Alejandra , Cortés-Hernández Dora A.
Published: March 2009

Hydroxyapatite, porcelain and wollastonite coatings on stainless steel 316L were produced by electrophoretic deposition (EPD) in ethanol and acetone using a voltage between 200 and 1000 V during 0.5 to 60 s. The particle size distribution of the starting suspension was 0.3 to 4.9 microns with an average size of 1.5 microns. The coatings were analyzed using scanning electron microscopy. The amount of ceramic material on the surface of the metallic samples was evaluated by determining their difference in weight before and after the electrophoretic deposition process. The conductivity and zeta potential of the dispersing media were also evaluated. Dense, homogeneous and crack-free green coatings were obtained. The deposition rate was higher by using acetone as dispersing media. The higher zeta potential and the lower viscosity were attributed to be the cause of the better electrophoretic deposition of the acetone and methanol ceramic suspensions. Submicron particle coatings were then sintered between 800 and 1000 C during 2 h. The sintered coatings presented a very homogeneous polycrystalline structure free of cracks. The results show that the application of high voltage during short periods of time is an effective method to obtain ceramic coatings with good sinterability.
Electrophoretic Deposition of Zeolite 5A for Use in Supported Gas Separation Membranes
Authors: Sweet Wendi S. , Talbot Jan B. , Higgins Richard
Published: March 2009

Electrophoretic deposition was investigated as a procedure for preparing supported
membranes of zeolite 5A for use in gas separations. In particular, the addition of
polyethylene imine (PEI) to the non-aqueous bath was explored as means of improving gas
separation selectivity, deposit morphology, and adhesion. It was found that the addition of
PEI improved all of these qualities. Post-deposition treatments such as baking and coating
with polystyrene were also studied.
A Methodology of Off-Line Optimization for NC Milling Process
Authors: Yao Ying Xue , Liu Chang Qing , Li Jian Guang , Jing H.J. , Chen S.D.
Published: March 2009

Traditional adaptive control technologies in machining process optimization are limited in applications because they depend much on sensors, controllers and other hardware. An off-line optimization method for end milling process with constant cutting power is presented. On taking advantage of virtual machining which simulates milling process, acquires cutting parameters and predicts cutting forces, method taking constant cutting power as an objective is discussed to optimize feed rates and cutting speeds. Based on optimal result, the feed rates and spindle revolutions in NC program are re-scheduled. Controlled milling experiments show that machining time is reduced and machining stability is improved by using the optimized NC program.
Nanomechanical Properties of Single-Crystalline Silicon Wafer Irradiated by High-Energy Femtosecond Laser Pulses
Authors: Wang Yan Shen , Liang Ying Chun , Dong Shen , An Wei Wei , Wang Bo
Published: March 2009

High-energy femtosecond laser pulses were utilized to ablate single-crystalline silicon
wafer. Collateral damage areas around the ablation zone can be observed in microscope. The
morphology in such areas changes gradually. The microscopic morphology and nanomechanical
properties of the pre-polished back surface were measured by AFM and Hysitron TriboIndenter
respectively. The topography and roughness in the ablated, metamorphic and unaffected zone are
almost equal. Yet the elastic ratio and hardness on the back surface vary gradually with indent
positions, which coincide with the gradual morphological changes in the metamorphic zone on the
front surface. Such regular changes in nanomechanical properties, to some extent, reflect the
distribution of collateral damages near the ablated zone on the back surface. And they also testify
the occurrence of the ill effects that go against micromachining during high-energy femtosecond
laser irradiation.
Study on Surface Quality of Nano ZrO2 Ceramics in Grinding by the Aid of Ultrasonic Vibration
Authors: Xiang Dao Hui , Ma Y.P. , Zhao Bo , Chen Ming
Published: March 2009

Nano ceramics possesses excellent mechanical property and physical characteristics in
contrast to conventional engineering ceramics, so it has tremendous application prospect. Adopting
ultrasonic composite processing we describe the influences of grinding speed, grinding depth, wheel
granularity and no-spark grinding times on the surface roughness of nano ZrO2 ceramics. By means of
SEM and AFM the surface character and critical ductile grinding depth of nano ZrO2 ceramics in the
condition of conventional and ultrasonic grinding are also discussed. At last, the residual stress of
surface and crystalline phase transformation under the condition of conventional grinding and
ultrasonic vibration grinding were analyzed by X-ray diffraction. The research indicated that
ultrasonic vibration grinding could obtain nano finished surface with high efficiency. The residual
stress of nano ZrO2 ceramics surface is determined much by different grinding styles.
The Development of Special Drills for High-Efficient Drilling Austenitic Stainless Steel Part II: Coating Selection and Experiment Research
Authors: Chen Ming , Liu Gang , Jing Lu Lu , Hu Z.G. , Zhu X.F. , Li Z.W. , Xu H.
Published: March 2009

Coating is an effective method to solve the contradiction between the wear resistance and
the toughness for tool materials and the coated tool can yield satisfied cutting performances. Now
the coated high-speed steel (HSS) drill is widely used in drilling of stainless steel. This paper
studied the tool life of the TiN, the TiAlN and the TiCN coated special drills in drilling austenitic
stainless steel 1Cr18Ni9Ti through contrastive experiments. The tool life of the TiN coated drill was
only 81.5% of TiCN, and 66% of TiAlN because of its low oxidization resistance and hardness. The
wearing features of TiAlN and TiCN coating were also studied by experiments and the different
wear mechanisms were revealed. Finally the comparison of cutting performance was given between
TiAlN and TiCN coated drills and recommendation of coating selection for drilling austenitic
stainless steel was also presented. TiCN coating is suitable for HSS cutting tool base, which is often
used for drilling austenitic stainless steel at low speed. TiAlN coating is appropriate for tungsten
carbide cutting tool base, which is used for drilling austenitic stainless steel at high speed. The
special designed drill with optimal geometrical structure plus appropriate coating can yield long
tool life and high material removal rate in high-efficient drilling austenitic stainless steel.
Study on the Thermal Shock Resistance of Si3N4/TiC Nanocomposite Ceramic Tool Materials
Authors: Zhao Jun , Ai Xing , Lv Z.J.
Published: March 2009

By adding nano Si3N4 and nano TiC particles into the micro Si3N4 matrix, the Si3N4/TiC
nanocomposite ceramics were fabricated via hot pressing technique with Al2O3 and Y2O3 as
sintering additives. The thermal shock resistance of Si3N4/TiC nanocomposites were investigated by
means of indentation-quenching and quenching-retained strength testing methods. The results
revealed that the composite containing 10 wt.% nano Si3N4 particles and 15 wt.% nano TiC nano
particles was possessed of the highest thermal shock resistance, with its critical temperature
difference being 700~750. The toughening and strengthening mechanisms by the nano particles
addition are deem to be the essential course for the improved thermal shock resistance.
The Development of the Precise Double Sided Polishing Machine
Authors: Hu Gang Xiang , Hu Xiao Dong , Jin Yang Fu , Hu Xiao Zhen , Li W.
Published: March 2009

The functional materials such as sapphire, silicon wafer etc. are processed efficiently with ultra-smooth surface for the demand of the rapid development of the IC industry. The precise double sided polishing process is one of the main methods of getting the ultra-smooth surface for these materials. This paper introduces the structure and characteristic of the precise double sided polishing machine with a precise pressure control system equipped a new type electro-pneumatic digital servo valve. The works, such as machine design, development of the control system and optimization of process parameters etc. are carried out to meet the requirement of the precise double sided polishing machining process. This equipment has the characteristic of high machining precision and precise control capability, so it can be applied to the ultra-precise machining of the ultra-thin sapphire, silicon wafers etc.
A New Method of Structural Synthesis about the Partly-DOF Parallel Robot Mechanisms Based on the Screw Theory
Authors: Luo Ji Man , Cai Guang Qi , Chen X. , Yang B.J. , Huang W.
Published: March 2009

In this paper, based on some disciplinarians about the configuration design of Parallel Robot Mechanisms (PRM), the theory bases was established for parallel structural configuration design by developing different types of the partly degrees of freedom (DOF) parallel configuration designs. The new method to synthesize the partly DOF parallel mechanisms, called constraint accession, is provided to the classification of kinematical chains by use of screw theory. The active kinematical chains control the necessary DOF and the passive kinematical chains control the needless ones. In this paper, the relevant active and passive kinematical chains are put forward and the constraint chains are classified in detail. It is demonstrated by an example that new configurations can be obtained by assembling different kinematical limbs.
Dynamic Characteristic of HSK Tooling System
Authors: Wang Gui Cheng , Wang S.L. , Pei Hong Jie , Wu Wei Guo , Hua X.J.
Published: March 2009

According to in-depth analysis of the interface between HSK shank and the spindle, the
dynamic characteristic of HSK tool system in high speed machining is studied and numerical
simulation is carried out with FEM. The HSK tool system deformation, contact stress and the
change law of dynamic stiffness were opened out systematically. The relationship between the
dynamic stiffness and loading capacity was given. The rotational speed per minute when HSK taper
coordination position fails can be named limit maximum rotational speed Nmax of HSK. This
provides the foundation for the design of the high speed machine tool.
Relation Study of Roughness and Glossiness to Fractal for Granite Surface Profiles
Authors: Wang J.J. , Xu Xi Peng
Published: March 2009

The paper states the characteristic of Granite Surface Profiles. Gauss Filtering has been
adopted on original granite surface profiles curver, and then researching its Roughness and Fractal.
The method is an available and fast computation method for roughness and fractal to Granite
surface profiles. The Relation Study of Roughness and Glossiness to Fractal have been Study by
experiment.
Research on Vibration Tapping of Hardened Steel
Authors: Han R.D. , Yin B.L.
Published: March 2009

As high-speed steel tap is incapable of small-hole tapping (M3) in hardened steel, vibration
tapping is introduced in this paper to solve this problem. Theoretic analysis with fracture mechanics
indicates that the impact effect of the tap on the workpiece results in extended micro cracks and a
much lower tapping torque. And the torsional rigidity of the tap is enforced in vibration tapping as
proved by dynamic analysis. The experimental results show that with well chosen amplitudes, tapping
torque decreases as vibration frequency increases and increases with the increase of net cutting time
ratio, with the latter being the more significant influencing factor. In vibration tapping of hardened
steel, 24 threads can be machined with a single tap. Vibration tapping is then proved to be a practical
solution to the problem of small-hole tapping in hardened steel.
Study on Precision Control of Direct Metal Forming
Authors: Hu Xiao Dong , Li W. , Wang Q.C. , Qian N. , Zhao Wen Hong
Published: March 2009

This paper introduces a novel economical direct metal forming process, which combines of
traditional plasma welding processes and layer manufacturing process to fabricate sound metal part.
As high heat inputs during welding could affect parts surface quality, a CCD visual monitoring
system was used to monitor the process. To avoid the interferer from plasma arc light, the spectrum of
plasma arc was measured and analyzed, and a narrow band filter system was designed. The images of
molten pool were analyzed, and a fuzzy-PID controller was used to control the molten pool size.
Experimental results prove that using this system can improve parts surface quality.
Effects of Dynamic Characteristics of High-Speed Machine Tool/Cutting Tool System on Machining Quality
Authors: Zhang Song , Ai Xing , Zhao Jun , Liu J.G.
Published: March 2009

During high-speed machining, in order to make cutting tools work reliably and obtain ideal machining quality, not only good static characteristics, but also good dynamic characteristics are necessary. In this paper, with the help of the close combination of experimental research and modal parameter identification technique, the dynamic characteristics of the machine tool/cutting tool system were analyzed. Experimental results indicated that studying the effect of the dynamic characteristics on cutting force, machining accuracy and surface roughness could provide theoretical basis for effectively excluding the resonance zone that obviously destroyed machining quality and then optimizing cutting parameters further.
Nanometer Positioning System Based on Ball Screw
Authors: Lu Li Hua , Liang Ying Chun , Tachikawa H. , Guo Yong Feng , Shimokohbe Akira
Published: March 2009

This paper deals with nanometer positioning in the presence of friction. The object
researched is a ball-screw-driven and linear-ball-guide-supported table system. For such system,
models that do not account for friction can only be applicable to describe the macrodynamic behavior
which is significantly different from the microdynamic one. A PID controller is designed with
high-loop gain to suppress the effect of friction. The controller parameters are calculated by pole
placement according to macrodynamics, no identification of friction and friction model are necessary.
Experiment and simulation results indicate that nanometer positioning can be realized in this system
by the controller. In point-to-point (PTP) positioning for step heights from 0.1μm to 1mm, the
positioning error is within ±5 nm and the response characteristics are satisfactory.
Effects of Methane Concentration on Growth of Carbon Balls in Anode Nozzle and Arc Stability of DCPJ CVD Plasma Torch
Authors: Chen Rong Fa , Zuo Dun Wen , Li Duo Sheng , Xiang Bing Kun , Zhao Li Gang , Wang Min
Published: March 2009

High quality diamond film wafers with different thickness are prepared by high power
DC arc plasma jet CVD (DCPJ CVD) method using a CH4/Ar/H2 gas mixture. The effects of
methane concentration on the growth of carbon balls in anode nozzle and arc stability are studied
with theoretical analysis and experimental investigation. The results indicate that different sizes of
carbon balls may rapidly grow in the anode nozzle with methane concentration higher than 2
Vol-%, symmetry and uniformity of the rotating arc are strongly affected with the occurrence of
carbon balls, which will result in non-uniform deposition of diamond films over a large substrate
area. The methane concentration should be controlled at a low level to keep diamond film wafers
growth stable. Characterization by X-ray diffraction, Raman spectroscopy and SEM analysis are
also carried out.
Machining Simulation and Experimental Research of Complex Surface Parts Based on the PMAC
Authors: Liang Ying Chun , Chen Ming Jun , Sun Ya Zhou , Guo W.X.
Published: March 2009

In order to machine the complex free surface, in this paper, NC interpolation of any complex surface is realized used the recursive reconstruction algorithm. The interpolating errors of this algorithm are controllable, and its applicability is relatively wide. Then, these NC codes of the complex human’s free surface are obtained with data exchange of the manufacturing module in the software UG, and machining simulation is obtained used NC codes. Finally, these NC codes are entered into the NC micro-machine tool, which is controlled by the PMAC and developed by ourselves, and the experimental research of the human’s free surface has been finished on this machine tool. The experimental results show that the NC interpolation accuracy of this recursive reconstruction algorithm is very high, and the machining simulation and machining experiments of the complex human’s surface are completely consistent. The study result shows that the complex surface molding is smooth and continuous, and the machined surface is satisfactory.
A Suspending Abrasives and Porous Pad Model for the Analysis of Lubrication in Chemical Mechanical Polishing
Authors: Liu J.Y. , Guo Dong Ming , Jin Zhu Ji , Kang Ren Ke
Published: March 2009

The lubrication properties of the slurry between the silicon wafer and the pad in chemical mechanical polishing (CMP) are critical to the planarity of the silicon wafer. The effects of porous pad and suspending abrasives on the slurry film beneath the wafer become more prominent as the size of the silicon wafer becomes bigger. In order to explore the effects of porous pad and suspending abrasives on the lubrication properties of the slurry, a three-dimensional lubrication model based on the micropolar fluid theory and Darcy’s law is developed. The effects of the nanometer abrasives and the porosity of the pad on the lubrication of the slurry film between the silicon wafer and the pad are discussed.