bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial Stability of the Stem Fixed by Impaction Grafting Technique with Hydroxyapatite Granules in Revision THA
Authors: Matsuura Masanori , Ohashi Hirotsugu , Ebara Tsuneyuki , Yoshinaka Yasutaka , Kitano Kouzou
Published: March 2009

In revision THA with bone defects, impaction bone grafting is one proposed solution.
Morsellized allografts are commonly used, however allograft has some disadvantages. We tried to use hydroxyapatite (HA) granules in stead of morsellized allografts. Three types of HA granules were prepared. To facilitate the manipulation of HA granules, we tried to add arginine amino acid as
glue. These granules were impacted into the plastic femoral canal and collarless polished tapered stem was fixed with PMMA bone cement. Cyclic compression test and torsional test were performed using an Instron type mechanical tester. Mechanical stability of the stem fixed with HA granules for impaction grafting was superior to morsellized allografts. Adding arginine amino acid
to HA granules, impaction technique became easier and the initial stability of the stem was improved.
An In Vitro Comparative Study of Bioglass and Biologically Derived Hydroxyapatite with Bone Scintigraphy (BS) Method
Authors: Oktar Faik N. , Ozsoy S. , Turoglu H.T. , Altıntaş S.
Published: March 2009

Four rabbits received human derived HA to their left tibias. After 16 weeks bioglass was implanted to their right tibias. After other 16 weeks bone scintigraphies were taken with 99mTc- MDP. Three phase bone scan images showed no evidence of inflammation and superior vascularization rates at implantation sites. In this study, bioglass demonstrated higher uptake of 99mTc-MDP comparing to HA, suggesting a higher vascularization rate and better osseointegration.
Osteoblastic Response to Resorbed Ceramic Surfaces; The Role of the Osteoclast in Osteoconduction
Authors: Spence Gavin M. , Patel Nelesh , Brooks Roger A. , Bonfield William , Rushton Neil
Published: March 2009

The mechanism by which carbonate substitution within the hydroxyapatite (HA) lattice improves osteoconduction is unclear. Discs of dense, sintered, phase-pure HA and carbonate substituted hydroxyapatite (CHA) were cultured with human CD14+ cells in the presence of macrophage-colony stimulating factor (M-CSF) and soluble receptor activator of nuclear factor (NF)-κB (sRANKL), during which time osteoclasts developed and resorbed the ceramic surface.
Discs were then seeded with human osteoblasts (HOBs), and proliferation and collagen synthesis measured. Proliferation was increased on resorbed compared to control (unresorbed) surfaces on both materials. Collagen synthesis was increased on CHA compared to HA, an increase accelerated on a previously resorbed surface. The results suggest that osteoclasts can condition
synthetic bioceramic surfaces and alter the responses of osteoblasts which subsequently populate them. Carbonate substitution may enhance osteoconduction via effects on enhanced bioresorption.
Effect of the Concentrations of the Starting Solution on the Syntheses and Powder Properties of Hollow Tricalcium-Phosphate Microspheres by Ultrasonic Spray-Pyrolysis Technique
Authors: Ohno Toshiki , Aizawa Mamoru
Published: March 2009

We synthesized tricalcium phosphate (TCP) microspheres using an ultrasonic spray-pyrolysis technique, and investigated the effect of the concentrations of the starting solution on the powder properties. The XRD pattern showed that the crystalline phases of the resulting powders were β-TCP/HAp biphase in the case of pyrolysis temperature at 850 °C and TCP single phase at 1000 °C. The Ca/P molar ratios were determined by XRF to be at 1.50±0.03. The particle shapes of the powders were observed by SEM; the diameters of the microspheres were
narrowly distributed from 0.5 to 4 µm. The mean particle diameters of the resulting powder increased with the concentration of the starting solutions and could be controlled in the range of 0.85-1.4 µm. When the compressed powder was sintered at 1050 °C for 5 h , the relative density of the sintered compact attained to 97%.
The TCP microspheres had good sinterability.
Sintering Effect on Mechanical Properties of Composites of Bovine Derived Hydroxyapatite (BHA) with Titanium
Authors: Ozyegin L.S. , Gunduz Oguzhan , Oktar Faik N. , Oz B. , Agathopoulos Simeon , Salman S. , Ovecoglu L.
Published: March 2009

The aim of this study was to prepare high performance biomaterials suitable for use at load bearing applications with high bioactivity. The hydroxyapatite (HA) was prepared from bovine bones via calcination technique. The bovine derived HA (BHA) was mixed with 5 and 10 wt% metallic titanium (Ti) and the obtained homogenous mixtures were pressed to produce the test samples. The compacts were sintered at temperatures between 1000 and 1300°C. Compression
strength, density, and microhardness were measured. SEM and X-ray diffraction studies were also made. The best mechanical properties were obtained between after sintering at 1200-1300°C.
Biological and Biomechanical Properties of Chemically Modified SLA Titanium Implants In Vitro and In Vivo
Authors: Feng Yan Bo , Yan Wei Qi , Yang Di Sheng , Feng Jie , Wang Xiao Xiang , Zhang Sam
Published: March 2009

The objective of this study was to evaluate the interface shear strength and the responses of osteoblast-like cells to titanium implants with a sandblasted and acid-etched surface modified by alkali and heat treatments (SLA-AH). The implants with machined and SLA surface served as controls. Each type of implant was characterized by scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis. In vitro assays were made using human osteoblast-like cell culture on different surfaces. The rectangle plates were also transcortically implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 4, 8 and 12 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. By SEM examination, SLA surface combined with AH treatments revealed a macro-rough surface with finely microporous structure. The in vitro assays showed that the SLA-AH surfaces exhibited more extensive cell deposition and improved cell proliferation as compared with controls. Pull-out test demonstrated that the SLA-AH treated implants had a higher mechanical strength than the controls at all interval time after implantation. Histologically, the test implants revealed a significantly greater percentage of bone-implant contact when compared with controls. The results of this study suggest that a useful approach by combined processes could optimize implant surfaces for bone deposition and produce distinct biological surface features.
Histomorphometric Analysis of Zirconia/Alumina Composite and CP Titanium Treaded Implants in Rabbit Tibia
Authors: Kam Min Hee , Han Jung Suk , Yang Jae Ho , Lee Jai Bong , Kim Dae Joon , Lee Won Jun
Published: March 2009

The osseointegration rate of a new zirconia/alumina composite ceramic implant material, (Y,Nb)-TZP/ alumina, was compared with conventional titanium implant in the rabbit model. Four different groups of threaded implant were compared after 4 and 6weeks healing period. The bone implant contact ratio and bone volume was evaluated by undecalcified histologic sections. The surface of each implant group was observed under SEM. Within the limitations of this study, Zr/Al composite ceramic implants demonstrated favorable bone response compared to titanium implant. This material demonstrated a possibility of an alternative to titanium dental implant. Further studies are needed to confirm this result.
Biocompatibility of the Outer Prismatic and the Inner Nacreous Layers of Four Different Molluscs
Authors: Oktar Faik N. , Valério Patricia , Göller Gültekin , Agathopoulos Simeon , Goes Alfredo , Leite M. Fatima
Published: March 2009

The in vitro biocompatibility of aragonite material obtained from inner and out layers of
four different molluscs was tested. After grinding and sieving, the obtained fine powders were put in contact with primary osteoblasts derived from rat calvariae. The viability of the cells increased at about 10% in the presence of powders derived from Vennus Gallina outer layer and from Pecten Jacobaeus inner layer. In the case of the presence of the other 6 tested powders, there was no statistical difference in cells’ viability. With regard to alkaline phosphatase production, all the tested
powders induced a decrease of the production of this enzyme by osteoblasts. There was no evidence of any alterations in collagen production.
Influence of Sintering Temperature on Mechanical Properties of Biologically Derived Hydroxyapatite Bodies
Authors: Oktar Faik N. , Aydin H. , Göller Gültekin , Agathopoulos Simeon , Rocha G. , Sennaroglu B. , Kayali E.S.
Published: March 2009

The properties of sintered hydroxyapatite (HA), obtained from bovine femoral shafts via calcination method, were investigated utilizing scanning electron microscopy (SEM) and X-ray diffraction analysis together with measurements of microhardness, density, and compression strength. The production of HA from natural sources is preferred due to money and time saving reasons. The results indicate the new HA materials as promissing in biomedicine, since similar mechanical behaviour was obtained with previous studies.
Apatite Formation on Synthetic Polypeptide with β Sheet Structure in a Solution Mimicking Body Environment
Authors: Takeuchi Akari , Ohtsuki Chikara , Kamitakahara Masanobu , Ogata Shinichi , Tanihara Masao , Miyazaki Toshiki
Published: March 2009

Our previous study presented that sericin, a kind of silk protein, had high ability of apatite formation under a condition mimicking body environment when the sericin contains high content of β sheet structure. To confirm the effectiveness of β sheet structure on apatite nucleation, we attempted to synthesize of polypeptide containing β sheet structure and investigate apatite formation in 1.5SBF that
has 1.5 times the inorganic ion concentrations of human blood plasma. Poly(FEFEFEFG) was synthesized as the polypeptide consisting mainly of β sheet structure. Formation of hydroxyapatite was observed on the film of the poly(FEFEFEFG) after soaking in 1.5SBF within 7 days. We could confirm
that β sheet structure was effective even in the synthetic polypeptide.
Selective Protein Adsorption Property and Structure of Nano-Crystalline Hydroxy-Carbonate Apatite
Authors: Hayakawa Satoshi , Ohnishi K. , Tsuru Kanji , Osaka Akiyoshi , Fujii Eiji , Kawabata Kouji , Babonneau Florence , Bonhomme Christian
Published: March 2009

The selective protein adsorption property and the local structure around carbonate ions of nanocrystalline hydroxy-carbonate apatite were examined in this study. Considerable change in the selectivity in the adsorption of BSA and β2-MG was observed due to the incorporation of thecarbonate ions in hydroxyapatite lattice. Since the protein adsorption property seems to be related to the surface charge density of hydroxyapatite due to the carbonation, the chemical states of the incorporated carbonate ions were examined by the 31C CP-MAS NMR spectroscopy. At least four peaks assignable to carbonate ions in A-site(OH-) and B-site(PO4 3-) were observed in 13C CP-MAS NMR spectrum. Thus, we must take into consideration that the surface charge distribution and the decrement of polar groups such as OH- groups due to the distribution of carbonate ions in both Aand B-sites of the hydroxyapatite lattice are particularly favorable for β2-MG adsorption rather than for BSA adsorption.
A Low Temperature Co-Precipitation Preparation of Nano-Sized Zinc Containing β-Tricalcium Phosphate Powders
Authors: Miao Shun Dong , Weng Wen Jian , Cheng Kui , Song Chen Lu , Du Pi Yi , Zhao Gao Ling , Shen Ge , Wang Jian Xun , Han Gao Rong
Published: March 2009

Nano-sized zinc containing β-tricalcium phosphate (ZnTCP) powders were synthesized by a co-precipitation method. The co-precipitation took place in an ice-water bathed beaker, after further washing, freezing, lyophilizing and calcining at 800°C, the precipitates transformed to ZnTCP powders. The XRD pattern of the ZnTCP powders demonstrated a pure β-TCP phase. TEM observation revealed the particle size is about 100-120nm, which is favorable for TCP particles to form composites, such as polymer based composite, and as well to attain a desired microstructure. It was found zinc incorporation could eventually result in the decrease of particle size, thus be beneficial for its further application.
Electrostatic Atomisation Spraying: A Novel Deposition Method for Nano-sized Hydroxyapatite
Authors: Huang Jie , Jayasinghe S.N. , Su X. , Ahmad Z. , Best Serena , Edirisinghe Mohan J. , Brooks Roger A. , Rushton Neil , Bonfield William
Published: March 2009

Nano-sized HA (nHA) was applied to the surface of glass and titanium substrates using electrostatic atomisation spray (EAS) deposition. The phase purity of nHA was confirmed by X-ray diffraction. The nHA suspension consisted of rod–like particles 20-30nm in width and 50-100nm in length. The viscosity and conductivity of nHA suspension were 321 mPa s and 5.6 x 10-4 S/m, respectively. EAS of nHA in cone-jet mode was achieved at flow rate of 10-9 m3s-1 with the applied voltage
between the needle and the ring-shaped ground electrode of ~6 kV. Micrometer- to submicrometerscaled nHA islands were successfully deposited on the substrate surface. Image analysis showed that the area percentage of nHA increased with deposition time, it covered 50% of the surface area after 10s of spraying. Partial dissolution of nHA was observed after immersion in deionised water
for 1 month, particularly on the submicrometer sized nHA islands. Formation of a bone-like apatite layer was found after incubation in simulated body fluid (SBF K9) for 5 days, indicating the high bioactivity of the nHA deposits. In vitro culture with human osteoblast cells showed that the nHA islands were able to support the growth of HOB cells during 7 days of culture; the HOB cell activity increased with culture time as well as EAS deposition time. Immunofluorescence study showed that
HOB cells expressed well-organised actin stress fibres on nHA deposited surfaces after 3 days of culture. The result indicated that nHA deposition provided more favourable surfaces for cell attachment. Therefore, electrostatic atomization spray deposition of nHA offers great potential for the creation of bioactive surfaces on bioinert implant surface to provide improved interfacial bonding with host tissues.
Apatite Pattern Formation by Electrophoretic Deposition Transcribing Resist Pattern
Authors: Yamaguchi Seiji , Yabutsuka Takeshi , Hibino Mitsuhiro , Yao Takeshi
Published: March 2009

Apatite pattern was prepared by electrophoretic deposition (EPD) transcribing resist pattern. A porous polytetrafluoroethylene (PTFE) film was used as a substrate and attached on a cathode. The cathode for EPD was stainless plate with resist pattern. EPD was performed with a suspension of wollastonite particles in acetone and wollastonite particles were deposited on the substrate in the form of the resist pattern. When the wollastonite-deposited substrate was soaked in simulated body fluid (SBF), apatite was induced and then replaced wollastonite at the wollastonite deposited region on the substrate. As a result, apatite was formed in the pattern that traced the resist pattern. The minimum line width of the apatite pattern was about 100 µm.
Apatite Deposition on Polypeptides Derived from Plants in a Solution Mimicking Body Fluid
Authors: Miyazaki Toshiki , Ohtsuki Chikara , Ogata Shinichi , Ashizuka Masahiro
Published: March 2009

Organic-inorganic hybrids composed of organic polymer and apatite is quite attractive as novel bone-repairing materials since it has mechanical performance analogous to those of natural bone as well as bone-bonding ability, i.e. bioactivity. To fabricate such an apatite-polymer hybrid, biomimetic process has been recently paid much attention. In this process, bone-like apatite is deposited on the surfaces of organic substrates in simulated body fluid (SBF, Kokubo solution) having ion concentrations analogous to those of human extracellular fluid or more concentrated solutions. Previous studies showed that the apatite deposition is triggered by a catalytic effect of carboxyl groups (COOH) on the surfaces of the organic substrates. In this study, we examined apatite deposition on natural polypeptides derived from crops in a biomimetic solution. We selected gluten derived from wheat and zein derived from corn. Both of gluten and zein formed bone-like apatite on their surfaces in a solution that has inorganic ion concentrations 1.5 times those of simulated body fluid, when they were treated with 1 mol/L calcium chloride solution. High content of acidic amino acids such as glutamic acid and aspartic acid in gluten and zein would give large amount of carboxyl groups effective for the apatite nucleation.
Apatite Coating on Ti Surface Using Alternate Soaking Process
Authors: Kono Hiroshi , Miyamoto Motoharu , Sato Hideo , Ban Seiji
Published: March 2009

An apatite coating by an alternate soaking was undertaken on commercially pure titanium (cpTi) treated with concentrated acid and alkaline solutions. X-ray diffraction (XRD) patterns indicated that the diffraction peak intensities assigned to hydroxyapatite (HAp) increased with the reaction cycle. Fourier transform infrared spectroscopic study (FTIR) showed similar results with XRD. Scanning electron micrographs (SEM) of the deposits showed no observable change after the vacuum firing. It was confirmed that the reaction cycle greatly affected on the deposited amount of apatite on cpTi plates using the alternate soaking and the vacuum firing erased TiH2 formed during the acid etching, but was irrelevant to the crystallinity of the apatite.
Morphology of Fibroblastic Cells Cultured on Diamond-Like Carbon Coatings Produced by Plasma Immersion Using AFM and SEM
Authors: Uzumaki E.T. , Lambert C.S. , Bonugli L.O. , Santos A.R. , Zavaglia Cecília A.C.
Published: March 2009

For the potential use of diamond-like carbon (DLC) coating for biomedical applications, it would be important to evaluate the biological effects of these coatings. In this study, DLC coatings were deposited on glass coverslips using the plasma immersion process, which produces films with adhesion properties superior to those prepared with conventional techniques. Scanning electron microscopic and atomic force microscopic observations were used to study the morphology of fibroblasts growth on DLC coatings.
Primary Study of an Injectable In Situ Composite of Collagen/Calcium Phosphate Porous Scaffold for Bone Substitute
Authors: Yao Q. , Li Dong Xiao , Liu K.W. , Zhang Bo , Li H. , Fan Hong Song , Zhang Xing Dong
Published: March 2009

This study was to develop an injectable biocompatible and porous calcium phosphate
collagen composite cement scaffold by in situ setting. TTCP was prepared as main material of the CPC powder, and the collagen solution was added into the phosphoric acid directly to form the liquid phase. The injectable time (tI), setting time (tS) and setting temperature (TS), along with the
PH value were recorded during the setting process. The compressive strength, morphology and porosity were tested. With the increase of collagen, this novel CPC get a tI of 5mins to 8mins, tS of 20mins to 30mins, compressive strength from 1.5MPa to 4MPa, and the porosity from 40% to 60%. This study gave a possibility to form a porous scaffold of collagen/CPC composite with the nature of injectability and setting in situ.
Nano-Calcium Phosphate/PLLA Incorporated with bFGF as In Situ-Transplantable Carrier for Cartilage Regeneration
Authors: Huang Xin , Yan Wei Qi , Yang Di Sheng , Feng Jie , Feng Yan Bo , Gao Yan Bo , Weng Wen Jian
Published: March 2009

A novel composite of biodegradable Poly-L-lactic acid (PLLA) with the deposition of the nanosized amorphous calcium phosphate (NCP) particles was developed as tissue engineering scaffold. To improve the minor intrinsic healing capacity of cartilage tissue, the porous composite with desired degradation rate was incorporated with basic fibroblast growth factor (bFGF) and
evaluated in the in vivo environment. Full-thickness defects were created in the weight-bearing surface of the femoral condyles in a rabbit model. The defect was filled with and without NCP/PLLA scaffold as a carrier of bFGF. Gross morphology for the test implant showed that the defect was filled with regenerated tissue. It resembled cartilaginous tissue and restored the contour of the condyle at 8 weeks after operation. For the untreated control, no cartilage-like tissue was
observed at all defects. Histological analysis revealed neochondrogenesis and clusters of cartilaginous extracellular matrix observed with safranin-O staining at 4 weeks for the NCP/PLLA with bFGF treated defects. At 8 weeks after operation, well-formed and mature cartilage was resurfaced the defects. While only fibrous tissue replacement was observed for the control either at
4 or 8 weeks. Special staining for cartilage indicated the presence of highly sulfated
glycosaminoglycans and collagen, which were the major extracellular matrices of cartilage. This investigation showed the potential of NCP/PLLA loaded with bFGF in the study of in situ-transplantable carrier to improve healing of cartilage tissue lesion.
A Thermodynamic Approach to Long-Term Deformation and Damage for Polymeric Materials in Hygrothermal Environment
Authors: Chen Xiao Hong , Wang Su Su
Published: March 2009

In this paper, a thermodynamic approach is presented to model coupled fluid transport, heat transfer, long-term deformation and damage in polymeric materials. The well-known Gibbs free energy is expressed as a functional of stress, temperature and fluid concentration with damage being introduced as an internal state variable. Constitutive equations for nonlinear viscoelastic materials in hygrothermal environments are derived in memory functional forms. The kinetics of damage evolution induced by stress, temperature and fluid is described by a damage function with thermodynamic driving force. Governing equations for mass and heat transfer are obtained from transport laws relating fluid and heat fluxes to gradients of chemical potential difference and temperature. A superposition principle of time, temperature, fluid concentration, stress, and aging is proposed so that long-term property functions may be derived from momentary master curves by horizontal and vertical shifting. The approach provides a theoretical framework for evaluating longterm behavior of polymeric materials in hygrothermal environments from short-term experiments.
Strength and Energy Absorption of Aluminium Foam under Quasi-Static Shear Loading
Authors: Hou W. , Shen J. , Lu Guo Xing , Ong L.S.
Published: March 2009

Experiments were carried out to examine the behaviour of aluminium foams under quasistatic shear loading. Special fixtures were designed to clamp the both ends of a beam-like specimen while the load was applied via a punch, which led to failure by shearing along the clearance near the fixed end. Specimens were made of CYMAT foams with two nominal relative densities (12% and 17%) and several values of width. This study focuses on the maximum strength under shear and the essential energy in fracture. It has been found that the ultimate shear force increases linearly with the width of the beam, so does the total energy absorbed. Two empirical formulae have been obtained which relates to the relative density, respectively, the ultimate shear strength and energy absorbed in shearing.
Indentation Size Effect on Hardness of Nanostructured Thin Films
Authors: Lu Chun Sheng , Mai Yiu Wing , Shen Yao Gen
Published: March 2009

Based on nanoindentation techniques, the evaluation of hardness of two nanostructured thin films, AlN and Ti-Al-N, is discussed. In the case of AlN films, the indentation size effect of hardness can be modeled using the concept of geometrically necessary dislocations, whereas in the case of Ti-Al-N films, the measured hardness increases exponentially as the indentation depth decreases. The results show that, as thin films approach superhard, dislocation-based plastic deformation is gradually replaced by grain-boundary mediated deformation.
Microstructure and Properties of Spark Plasma Sintering AlN/BN Ceramics
Authors: Zhang Lian Meng , Li Mei Juan , Shen Qiang , Li T. , Yu M.Q.
Published: March 2009

Aluminum nitride-boron nitride (AlN/BN) composite ceramics were prepared by spark plasma sintering (SPS). The sintering behaviors of AlN/BN composites with 5~15% volume fraction of BN were studied. The influences of BN content, as well as the sintering temperature on the density, microstructure, mechanical strength, thermal conductivity and machinability of the composites were also investigated. The results showed that the full densification of AlN/BN composite ceramics could be realized by SPS technique at the temperature no higher than 1800°C
for 3 minutes. The thermal conductivity of AlN/BN composites is in the range of 66~79W/mK, and AlN/BN composites can be cut or drilled by carbides or even steel tools when BN content is 15% volume fraction. The mechanical strength of AlN/BN composites is about 330MPa and is not remarkably affected by the addition of BN. The improvement of mechanical properties of AlN/BN composite ceramics is due to the fine and homogenous microstructure developed in the SPS process.
Influence of Cu Content on Interfacial Structure and Mechanical Properties of 3Al2O32SiO2 Fiber Reinforced Al Matrix Composites
Authors: Geng Lin , Xu Hong Yu , Wang Jun Xiang , Zheng Zhen Zhu , Yu Ku Ai
Published: March 2009

In this paper, pure aluminium and Al-Cu (1%, 3% and 5% in mass fraction) alloy matrix composites reinforced with 35vol% 3Al2O32SiO2 short fibers were fabricated by a squeeze-casting technique. Interfacial structure and distribution of element of the composites were investigated by means of SEM, EPMA and TEM. The experimental results indicated that when pure aluminium was used as matrix, the interface was slick and chemical reaction occurred at the interface between
amorphous SiO2 and matrix Al. When Cu element was added into the Al matrix alloy, the amorphous SiO2 on the fiber surface remained. Further more, with the increase of Cu element, the amount of the retained amorphous SiO2 increased. The interfacial reaction was inhibited due to the Cu element diffusion and enrichment towards the short fiber surface. SEM observation showed that large amount of fiber was drawn out from the matrix and some of them have been ruptured. Tensile
test showed that the tensile strength of the 35vol% 3Al2O32SiO2sf/Al-Cu composite increased with the increasing of Cu content as compared with the Al2O3f/pure Al composite, the increment of the fracture strength of 3Al2O32SiO2sf/Al-Cu composite were 102%, 146% and 171%, respectively.
Strengthening Zirconia by Adding Both Nickel and Alumina Particles
Authors: Tuan Wei Hsing , Liu S.M. , Ho C.J. , Yang T.J. , Zhang Dong Ming , Zhang Lian Meng , Guo Jing Kun
Published: March 2009

In the present study, the processing-properties relationships of the ZrO2/(Ni+Al2O3) composites are examined. Dense composites were prepared either by pulse electrical current sintering (PECS) at 1350C for 5 minutes or by pressureless sintering (PLS) at 1600C for 1 h. The size of Ni particles is as small as 30 nm to 50 nm. Though the size of ZrO2 grains in the matrix increases as alumina and nickel particles are added, the strength of the ZrO2/(Ni+Al2O3) composites is significantly higher than that of monolithic ZrO2.
Colloidal Probe AFM Measurements of the Electrophoretic Force
Authors: Stappers Linda , Fransaer Jan
Published: March 2009

Colloidal probe atomic force microscopy is a very useful tool in the study of colloidal interactions. Although this technique has been applied to study interactions between a particle and a polarized electrode during electrodeposition, it has never been used to study interactions in high electric fields as encountered in electrophoretic deposition. In this work, a preliminary study was undertaken to verify whether colloidal probe AFM could be used to measure the electrophoretic force on a particle. It was found that the electrophoretic force could be detected by colloidal probe AFM under certain circumstances. In order to prevent that the contribution of the cantilever on the measurement of the electrophoretic force becomes large, the charge on the cantilever should be small compared to the charge of the particle, which is attached to the cantilever. Moreover, the area of cantilever surface which is oriented parallel to the electric field should be small to minimize the contribution of the cantilever.
EPD of a Sub Micron HA Powder for Biomedical Applications
Authors: Mayr Helmar , Ordung Marc , Ziegler Günter
Published: March 2009

Hydroxyapatite ceramics for biomedical applications are used in form of layers, granulates and bulk materials. A new method to produce layers or bulk materials is the electrophoretic deposition. To achieve layers with a thickness between 5 and 50 m the use of a fine powder with particle size in the sub micron range is essential. In this work we show that commercially available hydroxyapatite powders, which usually have a strong tendency to agglomerate, can be milled to particle sizes smaller than 500 nm. Using one of these powders and optimizing the parameters for the electrophoretic deposition thin, homogenous layers were produced.
Engineering Tolerances & Performance in Applied EPD
Authors: Zarbov Martin , Brandon David , Thon Assaf , Cohen Nissim
Published: March 2009

For the past 10 years Cerel has been engaged in the development of prototype, EPDprocessed,
micro-components, primarily for the microelectronics industry. In this contribution we
summarize some of the problems of integrating EPD into the production process, and discuss the
parameters that need to be considered and controlled. Suitable dispersion media and additives can
usually be found for powder of any chemical composition to be deposited by EPD, providing the
particle size and size distribution, and their surface to volume ratio are suitable. So it is the
geometrical requirements and the dimensional tolerances of the product that often limit the EPD
process. We give three examples: the EPD embedding of passive components in a punched ceramic
tape, the production of porous capacitor anodes by EPD, and the EPD formation and printing of
narrow conducting lines on a ceramic tape substrate. In each case the production process parameters
have been chosen to satisfy the engineering requirements while minimizing the the formation of
process defects. Defects include: variations in particle packing density; loss of adhesion and deposit
cracking, and surface roughness or thickness variations.
Influence of Dopants on the Suspension Properties and Reactive Electrophoretic Deposition (REPD)
Authors: Jung Dirk , Tabellion Jan , Clasen Rolf
Published: March 2009

Doped glasses are usually manufactured by melting of silica. As the melting point of
silica is 2100 °C, most of the suitable dopants evaporate. Hence, alternative processes for the
fabrication of glasses are needed. Sintering of nano-sized silica powders to full densety and
transparently occurs at 1400 °C because of its large sintering activity. Green bodies can be doped
by means of gas infiltration, by soaking of green bodies with salt solutions or by using mixtures
of different powders.
A further development of the electrophoretic deposition (EPD) is the reactive
electrophoretic deposition (REPD), where soluble salts are added into a suspension. The
dissolved ions are adsorbed on the surface of the particles and can be deposited with the particles
resulting in a homogeneously doped green body. Shaping of a green body and doping can be
achieved within only one process step via REPD. The feasibility of this process was shown first
for a suspension of SiO2 containing different amounts of boric acid or/and cobalt chloride. First
of all, the influence of different quantities of boron acid or cobalt chloride on suspension
properties like viscosity, stability and zeta-potential was investigated. Secondly, green bodies
were shaped by REPD and characterized regarding deposition rate, green density and amount of
dopant. Finally, sintering was carried out at different temperatures. Thus, it was shown that green
bodies doped with boric acid could be sintered to full density at lower temperatures compared to
undoped ones. However, the sintering temperature depends on the amount of boric acid added
into the suspension.
The New Technology of Floating Polishing of Large Die Surfaces
Authors: Xu Xiao Cun , Yuan Zhe Jun , Chen Yu Quan
Published: March 2009

During the transferring process of the large die surfaces, there are extensive needs of die
surface polishing. Since almost large die surfaces are free-form surfaces, currently, these are almost
manually implemented. In order to overcome this barrier, this paper focuses on a new technology of
floating polishing, including a) the design of polisher body which has five degrees of freedom and
realize the floating polishing while keep the polishing head being indifference equilibrium within the
working range, b) normal force of polishing head on die surface analyses and experimental
verification by using the slip line field method, and c) establishments of the interference boundaries
between dies surface features and polishing head. The research achievements will be used for the
development of a portable, state-of-the-art polishing machine and the optimization of the associated
polishing process parameters in near future.
Application of the Restoration Algorithm of Cutting Tool Images Based on Fuzzy Theory to Monitor Tool Wear Condition
Authors: Wang Ya Liang , Ji Shi Ming , Xie Yi , Lan X.J. , Lu Jian Sha , Jin Shou Song
Published: March 2009

The tool wear monitoring system based on the image processing and computer vision has better study value and foreground. During the cutting, the cutting tool is always at the movement state, thus, the real-time collected sequence images by CCD sensor are blurred with noise. As a result, we have to confront the problem how to get the high quality images, which is researched by this paper. The paper analyzes the reasons which causing the image blurred, brings forward a degradation function model and finds the degradation of tool wear images dues to the relative movement. According to this function model and combined with the application of fuzzy theory, the restoration algorithm is obtained. The membership function dealing with degraded images of cutting tools is put forward. It turns out that the images restored by this fuzzy restoration algorithm reach our aim.
Experimental Study on Green Cutting with Water Vapor as Coolant and Lubricant
Authors: Han R.D. , Liu Jun Yan , Zhang Y. , Zhang L.
Published: March 2009

Green cutting has become focus of attention in ecological and environmental protection. Water vapor is cheap, pollution-free and eco-friendly. Therefore water vapor is a good and economical coolant and lubricant. Water vapor generator and vapor feeding system are developed to generate and feed water vapor. The lubricating method of water vapor is that the water vapor jet flow is directly jetted on the cutting zone and it cancels the fluid phase penetrating the capillaries in cutting zone. So it increases the time reserve of penetration and improves the property of penetration and lubricating effect. In order to find the influenced disciplinarians on lubricating effect with nozzle diameter, the parameters of water vapor jet flow and cooling distance (the distance between nozzle and cutting zone), experiments are carried out which hard alloy YT15 (P10 type in ISO) tool is used in cutting C45 steel. Experimental results show that the cutting force becomes lowered and chip thickness becomes thinned with the nozzle diameter decreasing. With the saturated vapor pressure increasing and the cooling distance shortening, the cutting force is lowed and the chip thickness is thinned too. Therefore the application of water vapor as coolant and lubricant can realize the green cutting in industry.
Direct Joining of Acrylic Rubber to Cast Iron with Functional Nanofilm by Polymer Plating
Authors: Kang Zhi Xin , Li Yuan Yuan , Zhong C.W. , Shao Ming , Xia Wei
Published: March 2009

The nanoscale functional thin film with the affinity to acrylic rubber was formed on the
surface of a high ductile spheroidal-graphite cast iron by means of polymer plating of
6-diallylamino-1,3,5-triazine-2,4-dithiol monosodium salt. The direct joining of acrylic rubber to the
cast iron was achieved with the functional nanofilm during curing. High peel strength adherend of the
rubber/cast iron was obtained with suitable film thickness and good film quality under curing at 453 K
for 18 min. When the film thickness was 8.53 nm, peel strength of the adherend was high to 4.9
kNm-1, and its broken-out section was rubber cohesive failure. The film thickness considerably
affected peel strength and rubber coverage. Moreover, the current density of polymer plating had
largely influence on mass and quality of thin film, thereby on joining property of acrylic rubber to the
cast iron. The good joining property results from chemical bond within interfacial layer of acrylic
rubber chain and reactive groups of nanofilm polymer-plated on the surface of cast iron.
Thermal Shock Resistance of a New Ceramic Tool Material and Its Microstructural Characterization
Authors: Xu Chong Hai , Huang Chuan Zhen , Ai Xing , Wang H.Y.
Published: March 2009

Thermal shock resistance is one of the important properties for ceramic cutting tool materials in machining operation. Thermal shock resistance of a new SiC/Ti(C,N)/Al2O3 ceramic tool material is investigated in detail by means of the water quenching test. It indicates that the addition of Ti(C,N) and SiC is effective in the improvement of thermal shock resistance of the composite and the tested maximum temperature difference of thermal shock reaches about 330. Microstructures of the ceramic samples after thermal shock have been observed and analyzed by SEM focusing mainly on the morphologies of cracks and the peeling off of grains as well as the accompanied oxidation phenomenon at elevated temperatures.
Erosion Wear and Design Model of Functionally Gradient Ceramic AJM Nozzle
Authors: Liu Li Li , Deng Jian Xin , Zhou Jun
Published: March 2009

The stress states of the ceramic nozzle in abrasive jet machining (AJM) process are analyzed. Results shown that the maximum stress appears in entrance area of the nozzle and minimum stress in middle area, while the stress of exit area was lower than entrance area and higher than middle area. It can interprets why the entrance and exit area of the nozzle were worn badly. The idea of functionally gradient material (FGM) theory was used to design of ceramic nozzle. The purpose was to reduce the stresses at the entrance and exit area of the nozzle during AJM processes. The physical, composition distribution, and property parameter models of the FGM nozzle were established.
Quality Testing for Pressed Raised Character on Metal Label Using GRBF Networks
Authors: Lu Chang Hou , Cao J.H. , Li Jian Mei , Li Xue Yong
Published: March 2009

In accordance with the obvious characteristics of the pressed raised character image and the shortages of the template matching method.a new method of using the general radial-basis function neural network (GRBFN) for testing the quality of the pressed character is presented. The structures and training methods of GRBFN are fully analyzed, as well as the functionality of hidden layer, excited focus and area. The results show the checker based on GRBFN has highly checking ratio for the label pressed raised characters. It is suited to the quality testing of raised characters.
Effect of Sintering Temperature on the Mechanical Properties of Rare Earth Oxides Toughened Cermet Tool Materials
Authors: Xu Li Qiang , Huang Chuan Zhen , Wang Sui Lian , Liu Zeng Wen
Published: March 2009

The effect of sintering temperature on mechanical properties and microstructure of rare
earth oxides toughened Ti(C,N) ceramic cutting tool materials was investigated. The results showed
that the mechanical properties of Ti(C,N) based ceramics were greatly influenced by sintering
temperature. As a result, both of the density and mechanical properties of the materials sintered at
1350
and 1400 are worse than those sintered at 1450 and 1500. Low sintering temperature
results in low density and degraded mechanical properties, but too high sintering temperature results
in the precipitation of bond metal and thus reduces its fracture toughness. Intergranular fracture
mode of the material is mainly observed.
Study and Application on CVD Diamond Tools
Authors: Fu Tie , Yu Qi Xun , Pang Si Qin
Published: March 2009

Diamond film made by adopting the Chemical Vapor Deposition (CVD) technology is a promising superhard material. The mechanical and physical properties of CVD diamond is between natural diamond and hot press polycrystalline diamond. The cutting tools made by CVD diamond can machine many kinds of material, such as nonferrous metals, non metallic materials and composites. CVD diamond is classified as thin and thick films, and the thick film cutting tools are widely used. However, the superhard cutting tools cannot be applied to the cutting of iron family metal and molybdenum (Mo). In this paper, data and curves on machining test of CVD diamond cutting tools are listed and then analyzed.
Research on Electrochemical Micromachining System and Related Techniques
Authors: Li Xiao Hai , Wang Zhen Long , Zhao Wan Sheng
Published: March 2009

Electrochemical machining (ECM) has been rarely applied in micromachining because the electric field is not localized. In order to explore the feasibility of applying ECM to micromachining at micro to meso-scale, an experimental setup with precision control over electrochemical micromachining (EMM) was developed, which is in fact a multifunctional machine tool. The micro tool electrodes for EMM can also be fabricated by micro electrical discharge machining (EDM) on the same machine tool. A high-frequency short-pulse micro-energy MOSFET power supply was designed. Lower machining voltage and lower concentration of passivity electrolyte are utilized together to localize dissolution area in EMM. A micro hole 45 ,m in diameter was drilled by EMM on stainless steel foil with 100 μm thickness. A new approach of fabricating microstructures by means of EMM milling using a simple micro tool electrode is proposed, and a shaped hole and a micro cantilever beam with high precision were acquired by EMM milling. The satisfactory process results indicate the potential capability of EMM for higher machining accuracy and smaller machining size.
Fast Positioning Technology of High Acceleration Stage
Authors: Li Yun Tang , Ding H.
Published: March 2009

Profiting from its high stiffness and ratio of push to weight, the stage directly driven by linear motor can reach extremely high acceleration. However, because the stage doesn’t have transmission parts, signals of the control system may excite high frequency vibrations in it directly, which limit the tuning range of controller’s parameters, prolong the stage’s settle time and influence its efficiency and positioning performance. This paper presents the stage’s dynamic characteristics by modeling simulation and experimental modal analysis (EMA). According to the dynamic characteristics, a time delay filter (TDF) is used in the controller, then the stage’s vibrations are restrained and its settle time is reduced distinctly.
Biomorphic SiC Ceramics Prepared by Organic Template Method
Authors: Qiao Guan Jun , Jin Zhi Hao , Qian Jun Min
Published: March 2009

Dense SiC/Si ceramics were prepared by a silicon melt infiltration method. Highly porous SiC ceramics with a wood-like microstructure were prepared by silica sol infiltration and carbothermal reduction reaction. Furthermore, laminated SiC/Si composites were also prepared by the carbonization and silicon melt infiltration of stacked papers. The microstructure and characteristics for this series of materials were determined and compared.
Synthesis of SiC Nano-Powders by Solid-Vapor Reaction
Authors: Lee Seoung Soo , Kim Jae Won , Jung Yeon Gil , Lee Je Hyun , Yoon Jae Hong , Jo Chang Yong
Published: March 2009

Silicon carbide (SiC) nano-powders are successfully synthesized by a reaction between
carbon nano-powders (carbon black) and SiO gas at 1300°C for 9 hrs in dynamic argon atmosphere
(flow rate; 400 cm3 min-1), using the solid-vapor reaction method. The particle size of synthesized
SiC nano-powders is below 40 nm and the shape is uniform. Unexpectedly, SiC nano-fibers are also
coexisted in the SiC nano-powders. The quantitative and qualitative properties of the SiC nanopowders
and nano-fibers are analyzed by scanning electron microscopy (SEM), transmission
electron microscope (TEM), and X-ray diffraction (XRD). Carbon residuals removed by heating
over 700°C in air are estimated by thermogravimetry analysis (TGA). It is found that the SiC nanopowders
are easily produced by direct synthesis via the solid-vapor reaction method. The
morphological characteristics of the resulting SiC nano-powders are dependent upon the
morphology of carbon black used as precursor.
Fabrication and Estimation of Au Coated γ-Fe2O3 Nanoparticles for Separation and Purification of Biomolecules
Authors: Kim S.H. , Yang Jae Kyo , Lee K.J. , Choa Yong Ho
Published: March 2009

Au coated γ-Fe2O3 nanoparticles were prepared by the changing of surface charge of Au
and γ-Fe2O3 nanoparticles with pH. Well Au coated γ-Fe2O3 nanocomposite particles developed in
the range between isoelectric point of Au and that of γ-Fe2O3 nanoparticles. Immobilization of
glutathione (GSH), crystalline polypeptide containing mercapto group, was successfully performed
on the well Au coated γ-Fe2O3 nanocomposite particles. Properties of nanoparticles and GSH
immobilized Au/γ-Fe2O3 were characterized by UV-vis, LPA, XRD, and TEM.
Improvement in Oxidation and Thermal Shock Resistance of Molten Glass-Coated Carbon Materials by Interfacial Control
Authors: Wada Masashi , Kitaoka Satoshi , Kawashima Naoki , Yasutomi Yoshiyuki , Yamada T. , Osa Noburou , Naitou Kazuyuki , Koyama Mitsuhiko
Published: March 2009

The coating of molten silicate glass on a porous carbon substrate was developed, without the formation of cristobalite at the carbon-glass layer interface, in order to improve the steam oxidation and thermal shock resistance. Initially, suitable conditions for coating were assumed from thermodynamic analysis. Based on these calculations, the wettability of the carbon to molten glass was modified by infiltration and pyrolysis of a Si-N precursor, and the coating with glass was carried out under higher N2 partial pressures. As a result, carbon substrates were completely sealed with glass, without the production of cristobalite at the interface, and the glass was infiltrated into the substrate. In contrast, coating with glass at lower N2 partial pressures, such as in Ar, were followed by the formation of cristobalite along with many pores at the interface. The structural changes occurring as a result of variation of the N2 partial pressure during sealing with glass are in good agreement with the thermodynamic analysis. The glass-coated carbon materials, which were fabricated at higher N2 partial pressure, possessed excellent steam oxidation resistance and thermal shock resistance.