bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Hydroxyapatite on Bonding Strength in Light Curing Glass Ionomer Dental Cement
Authors: Chae M.H. , Lee Yong Keun , Kim Kyoung Nam , Lee Jae Hoon , Choi B.J. , Choi H.J. , Park K.T.
Published: March 2009

The mineral phase of bone and teeth is mainly hydroxyapatite. Currently there are
numerous researches being conducted on the effect of the addition of hydroxyapatite to dental materials. Among them, several studied were published stating that the addition of hydroxyapatite to composite resin or glass ionomer cement resulted in an improvement in bonding strength and
physical properties Therefore, this study will investigate the effect that the addition of
hydroxyapatite to light curing glass ionomer cement has on bonding strength. Two different light curing glass ionomer cement products were selected (FujiⅡLC, GC Cor, Japan and Vitremer™ , 3M/ESPE, USA) and hydroxyapatite was mixed into the light curing glass ionomer cement at various concentrations to create hydroxyapatite-light curing glass ionomer cement mixture. In order to
confirm that hydroxyapatite-light curing glass ionomer cement met the basic requirements of dental materials, sensitivity to ambient light, depth of cure, and flexural strength were tested. From the results of the above mentioned tests, the hydroxyapatite-light curing glass ionomer cement with the
most superior physical properties for each product (15% HA-Fuji Ⅱ LC, 20% HA-Vitremer™)was bonded to the teeth and then immersed in artificial saliva(36.5°C) for four weeks. Finally the sectioned surface was observed under SEM after measuring the bonding strength. As the hydroxyapatite concentration increased, the depth of cure decreased. However flexural strength increased and there was not much change in the sensitivity to ambient light. Bonding strength, which
was the main focus of this study, increased with the addition of hydroxyapatie and scanning electron microscope findings show a more cohesive type of fracture in the material with bone like apatite material formation along the tooth-material interface.
Stability of Cultured Osteoblasts on Calcium Phosphate Ceramics
Authors: Oshima Akira , Tadokoro Mika , Hirose Motohiro , Takakura Yoshinori , Ohgushi Hajime
Published: March 2009

Cultured osteoblasts with mineralized matrix (regenerative cultured bone; RCB) have been used for patients having osseous defects. The RCB can be fabricated on various ceramic substrata using patient’s mesenchymal stem cells (MSCs) at our cell processing center (CPC). Since we have to transport the RCB for hospitals outside of our town, the RCB should maintain the cell viability for a long time. To determine a suitable condition for transportation of the RCB, stability of the RCB was analyzed by biochemical assays. Even outside CO2 incubator, the RCB kept high level of viability until 24 hours at 25°C and also showed low level of cytotoxicity for 24 hours at 37°C and 25°C. On the other hand, the RCB incubated for 24 hours at 4°C outside CO2 incubator resulted in extremely low level of viability with obvious cytotoxicity. These data indicated that stability of the RCB can be maintained for 24 hours at 37°C and 25°C, but not at 4°C. Therefore, the RCB derived from patient’s MSCs can be transported and utilized for the patients at hospitals far away from the CPC.
Anorganic Bone Mineral Coated with Tetra-Cell Adhesion Molecule Enhances Bone Formation in Rabbit Calvarial Defects
Authors: Lee Ji Ho , Park Jin Woo , Choi Byung Ju , Kim In San , Suh Jo Young
Published: March 2009

This study was performed to evaluate the effect of anorganic bone mineral (ABM) coated with Tetra-Cell Adhesion Molecule (T-CAM) for bone formation in rabbit calvarial defects and compare the capability of bone formation in ABM coated with T-CAM (ABM/T-CAM) to that in commercially available ABM coated with a synthetic peptide (P-15) which mimics the cell-binding domain of type I collagen, PepGen P-15TM. T-CAM composed of four cell adhesion molecules (RGD, PHSRN, EPDIM, and YH) was synthesized and ABM/T-CAM were prepared by absorbing
T-CAM on ABM (OsteoGraf/N-300; Densply Friadent Ceramed Corp., USA). Two 9-mm diameter, full-thickness calvarial defects were made in each rabbit parietal bone and sixteen adult male rabbits were used in this experiment. The defects were reconstructed according to four treatment groups: unfilled, BM-grafted, PepGen P-15TM-grafted, and ABM/T-CAM-grafted. The animals were
sacrificed at 2 and 4 weeks after surgery for histologic and histomorphometric evaluation. An active new bone formation were observed in the defects of ABM/T-CAM and PepGen P-15TM grafted groups at 2 and 4 weeks of healing in histologic observation. The results of histomorphometric analysis revealed higher new bone formation in ABM/T-CAM-grafted (14.62±0.6% at 2 weeks,
15.33±2.4% at 4 weeks) and PepGen P-15TM-grafted (12.46±1.0% at 2 weeks, 18.14±1.7% at 4 weeks) groups than in unfilled control (7.03±2.3% at 2 weeks, 8.71±3.4% at 4 weeks) and ABMgrafted (6.59±1.7% at 2 weeks, 9.25±0.8% at 4 weeks) groups at 2 and 4 weeks of healing with statistical significance (P<0.01). The results of this study indicated that the immobilizing T-CAM on
ABM enhances the capability of bone substitutes to serve as an effective habitat for bone forming cells in vivo. In conclusion, we suggested that this composite graft material, ABM/T-CAM may be served as an effective tissue-engineered bone graft material in osseous reconstructive surgery.
Fracture Characterization of High Density Polyethylene/Organoclay Nanocomposites Toughened with SEBS-g-MA
Authors: Bao S.P. , Tjong Sie Chin
Published: March 2009

High density polyethylene (HDPE)/organoclay nanocomposites toughened with maleated styrene-ethylene-butylene-styrene elastomer (SEBS-g-MA) were prepared by melt compounding. The structure and mechanical properties of such nanocomposites were investigated by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), tensile and impact techiniques. XRD measurements showed that meleic anhydride group of SEBS elastomer was beneficial in
forming an intercalated or partially exfoliated structure. The essential work of fracture (EWF) approach under tensile condition was used to characterize the fracture toughness of nanocomposites. The results indicated that the addition of SEBS-g-MA to the HDPE/organoclay nanocomposites greatly enhanced their fracture toughness.
Properties of Polypropylene/Carbon Nanotube Composites Compatibilized by Maleic Anhydride Grafted SEBS
Authors: Zhou Xing Ping , Xie Xiao Lin , Zeng Fandi , Li Robert Kwok Yiu , Mai Yiu Wing
Published: March 2009

Isotactic polypropylene (PP)/carbon nanotube (CNT) composites compatibilized by maleic anhydride grafted styrene-ethylene/butylenes-styrene copolymer (MA-SEBS) were prepared by melt compunding and compression moulding. The melt compouding torque, thermal properties, dynamical mechanical behavior, mechanical and anti-static properties of the PP/CNT composites
were systematically invertigated. The results indicated that MA-SEBS is an effective compatilizer for the PP/CNT composites. The melting and crsytallization temperatures (Tm and Tc), crystallinity degree (Xc) of the PP phase in PP/CNT composites increase remarkably with the CNT content. Compared with PP/CNT composites, the incorporation of MA-SEBS increases Tm, but decreases Tc, crystallization rate and Xc of PP phases in PP/MA-SEBS/CNT composites. Owing to MA-SEBS as a compatibilizer to enhance formation of a perfect percolation network, the thermal, mechanical and anti-static properties of PP/CNT are improved.
Fractal Behavior of Concrete Crack and Its Application to Damage Assessment
Authors: Cao Mao Sen , Ren Qing Wen
Published: March 2009

In this study, the fractal behavior of crack development in damaged concrete materials and its application to structural damage assessment are experimentally investigated. The experimental results demonstrate that the crack evolving is closely related to the characteristics of fractal behavior, and the surface-crack distribution of the damaged concrete structures possesses fractal characteristics. It thus indicates that the fractal may be capable of performing quantitative characterization of crack development, which cannot be comprehended by Euclidian geometry. The
application of fractal characteristics of surface-crack distribution in structural damage assessment is then investigated. By correlating the fractal dimension of surface-crack distribution with the model parameters (e.g., natural frequency) of different magnitudes of damage, a linear relationship exists between the fractal dimension and natural frequency. Since the natural frequency is one of the most
fundamental damage characteristic factors, the above linear relationship shows that the fractal dimension of surface-crack distribution is able to effectively act as an effective damage characteristic factor. Different from the conventional damage characteristic factors generated from vibration tests, this factor reflects structural damage from a new perspective of fractal analysis, and provides a viable and novel approach for health monitoring and safety evaluation for concrete structures.
Evaluating Mechanical Properties of Hard Coatings by Using Relativity Method
Authors: Bao Yi Wang , Bublik V.T. , Huang Jow Lay , Sung R.H.
Published: March 2009

Mechanical properties of coatings are usually affected by the substrate behavior and the thickness of the coating. The film on a substrate can’t be tested like a monolithic sample. Therefore, the absolute value of the mechanical properties of the film is often difficult to obtain, but the properties of a coated sample and a monolithic sample could be measured, and there must be a unique relation between them. Based on this consideration, a relativity method was proposed to evaluate the mechanical properties of coatings, including the hardness, elastic modulus. Satisfactory results have been obtained from the experiments using this clue. Moreover, residual stresses caused by mismatch of the coefficients of thermal expansion between the coating and substrate was calculated based on the uneven strain mode, it indicates that the interfacial shear stress concentrated at edges and maximum stress in coating is at the center.
The Effect of AlN Contents on the Properties of SiC-AlN Particulate Composites
Authors: Pan Yu Bai , Shi Xiao Mei , Sun Xing Wei , Guo Jing Kun , Wang Guillaume
Published: March 2009

SiC matrix composites can be reinforced and toughened by the second phase of AlN
particles. SiC-AlN composites are mixed by ball milling of the SiC and AlN powders, and then hot pressed under 40 MPa at 1950oC in Ar atmosphere. The object of this paper is to understand the effect of AlN contents on the properties of SiC-AlN particulate composites. AlN content is between 5 and 40wt%. For improving to mechanical properties of siC-AlN composites, the composition range of SiC-AlN composites are between 90SiC-10AlN and 80SiC-AlN20(wt%). Less or more
than this ratio would result in a microstructure with much pores or AlN grain-growth, respectively, two phenomena would decrease in the mechanical properties of SiC-AlN composites.
Cathodic Electrophoretic Deposition of Ceramic Nano-Particle Manganese Zinc Ferrite
Authors: Washburn Cody , Jorne Jacob , Kurinec Santosh
Published: March 2009

The electrophoretic deposition (EPD) of micro/nano-particle manganese zinc ferrite (Mnx
Zn1-xFe2O4) material has been carried out on silicon substrates. EPD is performed in isopropanol
(IPA) solutions containing charging and adhesion agents. The ferrite powders were prepared by
grinding ceramic sintered toroids of a commercial high permeability Mn-Zn ferrite. The ferrite film
has been deposited up to 4μm in thickness in 30 minutes showing good selectivity to silicon
patterned with 250nm thermally grown silicon dioxide. Additionally, selective deposition has been
observed on heavily doped p-type regions in n-type silicon substrates. The deposition process is a
self limiting process with the initial high elerophoretic current declining to 10% of its value in 10
minutes. This result suggests that majority of ferrite deposition occurs in first 10 minutes. The
deposition rate and zeta potential measurements indicate a high particle velocity on the order
5.7x10-3 cm/s with an electric field of 160V/cm generated across the 2 cm electrode spacing. An
amorphous like interfacial layer is observed in as deposited substrates. The scanning electron
micrographs indicate pattern filling and conformal deposition on copper planar micro-inductors
fabricated by chemical mechanical planarization. These results are promising for powder ferrite
material (hard and soft) to be selectively deposited for a wide variety of applications in
microelectronics passive components and in MEM’s based applications
Mechanisms of Electrophoretic Deposition
Authors: Van Tassel Jonathan J. , Randall Clive A.
Published: March 2009

There is no single mechanism of electrophoretic deposition (EPD). Just as there are
several mechanisms for creating a stable colloidal suspension, there are several mechanisms by
which particles can be destabilized to form an adherent deposit at an electrode surface. The goal of
this paper is to provide a listing of the mechanisms by which electrophoretic deposition can occur.
Several of these mechanisms have already been demonstrated, while others remain speculative.
The first step in this process is to provide a clear definition of what exactly EPD is, and, equally
important, to clearly distinguish EPD from three other very similar processes: electrostatic coating,
electrodeposition, and electrocasting. From this definition a series of logical steps leads to a list of
mechanisms by which a stable colloid can be converted to a stable particle compact.
Electrophoretic Deposition of Green Parts for LPS SiC-Based Ceramics
Authors: Novak Saša , Dražič Goran , Mejak Katja
Published: March 2009

Electrophoretic deposition of silicon carbide in ethanol suspensions was studied with the
aim to fabricate liquid-phase sintered (LPS) SiC-based ceramics densified at temperatures below
1500°C. The effect of suspensions composition (solids content, pH, sintering additives) on the
deposition rate and the properties of the deposits was analysed. The consistency of deposits and
their solids loading was found to be significantly dependent on composition of the starting
suspension: the highest solids loading (54.5 vol. %) for pure SiC was obtained with the addition of
citric acid, while for the suspension containing aluminum phosphate the deposition was more
successful from alkaline suspensions.
3D Particle Assembly in Micro-Scale by Using Electrophoretic Micro-Fabrication Technique
Authors: Hamagami Jun Ichi , Hasegawa Kazuhiro , Kanamura Kiyoshi
Published: March 2009

A novel micro-fabrication technique for particle assembly has been performed by an electrophoretic deposition (EPD) method using a local electric field in a colloidal suspension generated by a microelectrode. This unique EPD technique was called a “μ-EPD process”. Monodispersed polystyrene microspheres with diameters of 204, 290, and 320 nm were used in this study. A 50 μm Pt wire embedded into a polytetrafluoroethylene tube and an ITO glass slide were employed as the micro-counter electrode and the substrate, respectively. A slow deposition rate in the μ-EPD process was preferable to form a high quality micro-deposit consisting of a three-dimensional periodic polystyrene array. Under the optimized μ-EPD conditions, three-dimensionally ordered polystyrene particles were deposited in front of the micro-counter electrode. This micro-deposit constructed from polystyrene particles with a close-packed structure showed a characteristic optical absorption peak due to Bragg’s law.
Electrophoretic Deposition of Functionally Graded Monomorph
Authors: Chen Yan Hong , Li T. , Ma Jan
Published: March 2009

In the present work, investigation of the functional property of piezoelectric graded monomorph actuator systems is presented. The functional graded actuators were fabricated by electrophoretic deposition (EPD) using pure PZT and doped PZT materials. Actuators developed have shown gradual gradient variation in microstructure. It is noted that trend in microstructural gradient does not represent similar trend in piezoelectric property gradient. The displacement of microstructural graded and both piezoelectric and microstructural graded actuators were measured. The results show that the gradient distribution of the piezoelectric properties is important to improve the electromechanical performance of the actuator.
Quality Analysis of Pulsed Laser Cutting of Superalloy Sheet
Authors: Lv S.J. , Wang Yang , Ji Shi Jun
Published: March 2009

This paper presents the experiments of Nd:YAG pulsed laser cutting of GH3536 superalloy
sheet and investigates the influences of different cutting parameters on laser cut quality factors
including recast layer, kerf width and dross formation. The results show that the recast layer possesses
finer granularity and higher hardness than those of the matrix, and the thickness of recast layer
increases with increased pulse energy and decreases as the cutting speed and gas pressure increase.
Oxygen-assisted cutting comes with thick recast layers and argon-assisted cutting acquires thin layers.
The low-strength oxide layer worsens the kerf surfaces in oxygen-assisted cutting while
argon-assisted cutting produces unaffected surface quality and is suitable for applications with
subsequent welding.
Study on High-Speed WEDM in Gas
Authors: Wang Tong , Zhang Xin Fu
Published: March 2009

This paper investigates the influence on finish high-speed Wire-cut Electrical Discharge
Machining (WEDM) in atmosphere and emulsion liquid. Experimental results have shown that
WEDM in atmosphere offers a series of advantages such as better straightness accuracy and higher
removal rate (material removal rate). It was also found that the removal rate increased significantly
at a higher wire winding speed, with the straightness got worse at the meanwhile both in
atmosphere and emulsion liquid. Considering its better processing quality and higher removal rate,
the high-speed WEDM in gas possesses broad prospects for its application.
Framework and Modeling of Networked Manufacturing for Automobile Die
Authors: Sun J.K. , Li Zhao Qian , Huang Chuan Zhen , Gao Qi
Published: March 2009

To improve the collaboration efficiency of the networked manufacturing coalition for
automobile die enterprise, the networked manufacturing system framework is put forward. Then the
information model, resource model and organization structure model are studied one of the other.
The information model contains three layers lengthways and the product lifecycle is divided into 5
stages on landscape; for the resource model, the resource is classified and described, the
relationship between resource entities is analyzed. The participants of each member enterprise are
grouped according to the task relevance in organization structure model, and collaborative
discussion center is constructed for the participants to communicate. On the basis, the workflow
model is then discussed, the activity in business process is described with UML, then the UML
activity diagram is transformed to Petri net graph, thus the workflow model can be diagnosed and
analyzed.
A Two-Dimensional Fast Tool Servo Used for Real Time Error Compensation in Taper Turning
Authors: Gao Dong , Yao Ying Xue , Yuan Zhe Jun
Published: March 2009

In this paper, a two-dimensional (2D) fast tool servo driven by piezoelectric actuators for real time error compensation in taper turning is described. A 2D tool post is made with a new structure with three leaf springs for each axis and its mounting platform positions at a corner, which makes it convenient for mounting the cutter. A control technique, “Forecasting Compensatory Control” (FCC), is implemented to perform an on-line prediction of the machining errors encountered. The on-line cutting experimental results have verified that an improvement of about 40% was achieved for roundness error of the workpiece in the taper turning operation by using the developed control algorithm.
Research on Endless Wire Saw Cutting of Al2O3/TiC Ceramics
Authors: Meng J.F. , Li Jian Feng , Ge Pei Qi , Zhou R.
Published: March 2009

This article investigates the cutting of Al2O3/TiC ceramics using a fixed abrasive diamond
endless wire. The effect of wire speed and feed rate on material removal rate, cutting force, surface
roughness and wire wear is investigated. The cut surface of Al2O3 /TiC ceramics is studied. This
study demonstrates the advantage of fixed abrasive diamond endless wire cutting of Al2O3/TiC
ceramics.
Corrosion Resistance of TC4 Alloy Implanted by La+, Mo+
Authors: Li Xiang Feng , Wei Zhong Shan , Zuo Dun Wen , Wang Min
Published: March 2009

The surface treatment for TC4 alloy was conducted by MEVVA ion implantation method. The corrosion resistance of TC4 alloy implanted by La+, Mo+ were measured. It were found that Mo ion implantation improved corrosion resistance of TC4 alloy in acidic chloride solution, but La ion implantation gave the opposite result because they have different chemical activity. The more implanted dose of Mo+, the more improvement of corrosion resistance.
Study on Dry Electrical Discharge Assisted Profile Truing and Dressing of Diamond Wheel
Authors: Wang Yan , Zhou X.J. , Hu De Jin
Published: March 2009

Both diamond wheel and CBN wheel belong to super-abrasive wheels. Diamond wheels have superior grinding performance. The metal-bonded diamond wheel can grind hard brittle material component with a complicated shape precisely and efficiently. Because dielectric liquid is forbidden on numerical control optical profile grinder, the information on profile truing and dressing diamond wheel mounted on numerical control optical profile grinder is not readily available. In this paper, a novel truing and dressing method, namely dry electrical discharge (dry-ECD) assisted truing and dressing, is proposed. The experiments of dry-ECD assisted profile truing and dressing of diamond wheel are done by the authors. The experimental results show that both geometrical accuracy and surface topography of diamond wheel have attained technical requirement under appropriate truing and dressing conditions. There is not much difference in grinding abilities of new diamond wheel and dry-ECD assisted truing and dressing diamond wheel.
Three-Dimensional Micromachining Based on AFM
Authors: Hu Z.J. , Zhang S.G. , Zheng Xiu Hua , Yan Yong Da , Sun T. , Zhao Qing Liang , Dong Shen
Published: March 2009

With the development of science and technology, Atomic Force Microscope is widely applied to the field of machining process in nanometer scale. Due to the limitation of the inventive purpose of AFM, only height mode and deflection mode can be applied in AFM-tip micromachining. It can’t control the machining depth during the micromachining process at present. In this paper, a new micromachining system is set up, which composed of a high precision three-dimensional stage, an AFM, a diamond probe and a special control device. By utilizing variation parameters PID algorithm and controlling the machining depth directly, the micromachining system can resolve the problem mentioned above.
A Model for Milling Force Prediction in High-Speed End Milling of P20 Mold Steel
Authors: Zhao Jun , Ai Xing , Wang Su Yu , Liu Zeng Wen
Published: March 2009

This paper focuses on developing an empirical model for the prediction of milling forces in
high-speed end milling of P20 die-mold steel. The spindle speed, feed rate, axial and radial depth of
cut are considered as the affecting factors. The data for establishing the model are derived from
high-speed end milling experiments conducted on a 5 axis machining center according to the
principles of DOE (design of experiments) method. The influences of milling parameters on milling
forces are investigated by analyzing the experimental curves. Consequently, multiple-regression
analysis is applied in developing the empirical model. Furthermore, the significances of the regression
equation and regression coefficients are statistically tested in this paper to validate the model.
Evaluation of the Development Level of China' s Precise Finishing Industry
Authors: An Shi , Wang J. , Qian J.P.
Published: March 2009

Recognizing and evaluating the development level of a country’s precise finishing
industry, is the prerequisite to the country’s decision-making on the development planning and
guiding policies in this industry. This paper presents a Fuzzy Analytical Hierarchy Process (FAHP)
Model on the base of “Expert Knowledge”. This model combines the advantages of Fuzzy Evaluation
Method and Analytical Hierarchy Process (AHP), and can give relatively reliable evaluation results
with incomplete information of the evaluation criteria. The application of the FAHP Model provide
reliable comprehensive evaluation data.
Hydrothermal Synthesis of Nano ZrO2 Powders
Authors: Duran Cihangir , Yu Jia , Sato Kimiyasu , Hotta Yuji , Watari Koji
Published: March 2009

Hydrothermal synthesis of nano ZrO2 powders were carried out at a temperature range of
100 to 200°C, using zirconium solution. Formation of ZrO2 formation was accelerated with
temperature and precipitation of ZrO2 took place directly from the solution. XRD analysis revealed
that monoclinic ZrO2 was formed at all conditions. Crystallite size was found to range from 2.6 to 4
nm. Mean particle size increased from 93 nm at 135°C to 125 nm at 200°C after reaction time of 2 h.
Mechanical Properties of Transparent Polycrystalline Silicon Nitride
Authors: Sung Rak Joo , Kusunose Takafumi , Nakayama Tadachika , Kim Yoon Ho , Sekino Tohru , Lee Soo Wohn , Niihara Koichi
Published: March 2009

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering
with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered
at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent
polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as
density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The
effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was
investigated. The properties were changed depending on the amount of α/β phase. The hardness and
Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection
of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased
with decreasing the volume fraction of β-phase Si3N4.
Electrical Resistance Behavior during Tensile Loading of Al2 O3 Fiber-Nano RuO2-Glass Composites
Authors: Jang Byung Koog , Matsubara Hideaki
Published: March 2009

The conductive composites in which nano RuO2 particles are dispersed throughout a glass matrix have been successfully fabricated by sintering at 850°C. The sensing properties of conductive composites were investigated in real time during tensile testing by measuring the electrical resistance. It is shown that the excellent sensing ability based on electrical resistance changes in the low strain range was due to deformation of conduction paths between nano RuO2 particles by brittle fracture of the glass matrix. The change of electrical resistance depends strongly on the volume percent of Al2O3 fiber reinforcement.
Corrosion Resistance of Commercial Si3N4 Bearing Balls
Authors: Chimal-Valencia O. , Corral-García M.S. , Kume H. , Nishikawa Yoshito , Iwasa Mikio , De la Torre S.D.
Published: March 2009

The corrosion rate (Cr) of commercially available ball bearings made of silicon nitride
(Si3N4) of high degree (HD) and standard quality (S) was measured at hydrothermal conditions in
different aqueous concentrations of sulphuric acid (H2SO4) and sodium hydroxide (NaOH). The Cr
magnitude for the materials diminished when increasing the acid concentration. At higher
concentrations of H2SO4 (98%) the formation of SiO2 on the surface of the balls inhibited the
progress of corrosion. The corrosion rate of the materials was increased when the sodium
hydroxide solution concentration was increased. The surface of the materials was analyzed by
means of scanning electron microscopy (SEM), while the corrosion rate was determined based on
weight losses.
Crack-Healing under Cyclic Stress and Improvement of the Resultant Fatigue Strength of Si3N4/SiC
Authors: Takahashi Koji , Ando Kotoji , Saito Shinji
Published: March 2009

Si3N4/SiC composite ceramics were hot-pressed in order to investigate their crack-healing
behavior under cyclic stress and the resultant static fatigue strength. Semi-elliptical surface cracks of
100 μm in surface length were made on each specimen. The pre-cracked specimens were crack-healed
under a cyclic bending stress of 210MPa in air at 900, 1000, 1100, and 1200 °C. The bending strength
and static fatigue strength of the crack-healed specimens were systematically investigated at each
healing temperature. The specimens which has been crack-healed and static fatigue-tested at 900 and
1000 °C showed lower static fatigue strength than those tested at 1100 and 1200 °C. Detailed
investigation on the fracture surface of static fatigue-tested specimens showed that oxidation of the
base material had strong effects on the static fatigue strength. It was found that when the specimens
were pre-oxidized in air at 1300 °C, the surface was covered by a protective oxide layer, leading to a
significant improvement of static fatigue strength at 900 and 1000 °C.
La2O3 Doped Y2O3 Stabilized ZrO2 TBC Prepared by EB-PVD
Authors: Matsumoto Mineaki , Yamaguchi Norio , Matsubara Hideaki
Published: March 2009

Effect of La2O3 addition on thermal conductivity and high temperature stability of YSZ coating produced by EB-PVD was investigated. La2O3 was selected as an additive because it had a significant effect on suppressing densification of YSZ. The developed coating showed extremely low thermal conductivity as well as high resistance to sintering. Microstructural observation revealed that the coating had fine feather-like subcolumns and nanopores, which contributed to limit thermal transport. These nanostructures were thought to be formed by suppressing densification during deposition.
Investigation of Strontium-Niobium Oxides for Application to Thermal Barrier Coatings
Authors: Shida Masato , Akiyama Katsunori , Nagano Ichiro , Murakami Yuichiro , Ohta Satoshi
Published: March 2009

We have been trying to find new oxide compounds with large thermal expansion coefficients and low thermal conductivities by means of a material calculation technique. Among thousands of compounds in the databases, we found that there were some materials with low thermal conductivities and large thermal expansion coefficients in the group of strontium-niobium oxides. For example, Sr4Nb2O9 has a thermal expansion coefficient of 14.510-6 / and thermal conductivity of 1.0 W/mK, although a slight amount of other phases appear during long-term annealing. These thermal properties are better than those of yttria-stabilized zirconia, which is the standard material for thermal barrier coatings. To prevent the precipitation of other phases, we prepared the solid solutions, Sr4Nb2-xMxO9. In this study, the thermal conductivities and thermal expansion coefficients of these solid solutions were measured, and their thermal stabilities were evaluated by long-term annealing.
Development of Nanostructured Al2O3-Ni HVOF Coatings
Authors: Hannula Simo Pekka , Turunen Erja , Keskinen Jari , Varis Tommi , Fält Teppo , Gustafsson Tom E. , Nowak Roman
Published: March 2009

HVOF thermal spraying has been developed to deposit dense Al2O3-coatings for improved
protective properties. As compared to generally used plasma sprayed coatings HVOF coatings can be
prepared much denser and thus are better suited for applications where protective properties of the
coating are needed. In this paper we describe the development of HVOF spraying technologies for
nanocrystalline Al2O3- and Al2O3-Ni-coatings. The microstructure and the mechanical properties of
these novel coatings are reported and compared to a conventionally processed Al2O3-coating.
Reliability during Thermal Shock Testing of NiCr Films on Mn-Ni-Co Oxide Substrates
Authors: Jeon Min Seok , Song Jun Kwang , Lee Eui Jong , Lee Hee Soo , No Tae Hyung , Kim Duck Hee , Park In Gil
Published: March 2009

There is an increasing reliability concern of thermal stress-induced failures in multilevel coatings in recent years. This work reports investigations of cracking of NiCr coatings due to thermal cycling. The temperature cycling in accelerated testing was performed in three temperature range of 150, 175 and 200°C. The NiCr coatings were considered to have failed when the sheet resistance changed by 30% relative to an initial value. As the cyclic repetition of thermal shock increased, the sheet resistance of NiCr coatings increased. The Coffin-Manson equation was applied to the failure mechanism of cracking of NiCr coatings and the SEM observation of cracks and delamination in NiCr coatings due to thermal cycling agreed well with the failure mechanism.
The Anisotropic Properties of the Tape Cast Si3N4 Ceramics with Rod-Like β-Si3N4 Seeds Addition
Authors: Zeng Yu Ping , Kondo Naoki , Hirao Kiyoshi , Kita Hideki , Ohji Tatsuki , Kanzaki Shuzo
Published: March 2009

Lu2O3 and SiO2 were used as sintering additives and rod-like β-Si3N4 seeds were added to
enhance β-Si3N4 grain unidirectional growth. Silicon nitride ceramics were prepared by tape casting
and gas pressure sinteringat 1950oC in 10 atm nitrogen atmosphere for 6 h. Compare to the no-seeded
Si3N4, the seeded and tape-cast Si3N4 ceramics have obvious anisotropic microstructure and
anisotropic properties. When a stress applied along with the grain alignment direction, the bending
strength of the seeded and tape-cast Si3N4 at 1500oC was 738 MPa, which was almost the same as its
room temperature bending strength. However, the bending strength of the seeded and tape-cast at
room temperature was 556 MPa (perpendicular direction); and their thermal conductivity were 67
W/m·K (perpendicular direction) and 83 W/m·K (parallel direction), respectively. The anisotropic
properties of the seeded and tape-cast Si3N4 were attributable to the elongated Si3N4 grain alignment.
Fabrication of α-Sialon Nano-Ceramics
Authors: Xu Xin , Nishimura Toshiyuki , Hirosaki Naoto , Xie Rong Jun , Yamamoto Yoshinobu , Tanaka Hidehiko
Published: March 2009

Y- α-sialon (m=1.35, n=0.675) ceramics were prepared by high-energy mechanical
milling followed by spark plasma sintering. The milling promoted not only liquid-phase sintering,
but also phase transformation from β-Si3N4 to α-sialon. Under the same holding time of 5 min,
milled powder could be completely densified at 1500oC, which is about 250oC lower than that
required for as-received powder. The temperature where the phase transformation finished was
1600oC and 1750oC for milled and as-received powder, respectively. The grain size of obtained
dense ceramics from milled powder was significantly decreased. Nano-sized dense ceramics have
been obtained by sintering the milled powder at 1500oC for 5 min. Although 100 % α-sialon has not
been achieved, the nano-sized ceramics can be used for superplastic deformation, taking advantage
of small grain size and large amount of transient liquid phase.
Mineral Sand as a Low Cost Source of Nanomaterials
Authors: Kawahata Ryoji , Suzuki Yoshikazu
Published: March 2009

There are several TiO2-containing minerals, such as rutile (TiO2-based, typically 90-98%),
leucoxene (FeTiO3-TiO2 based, typically 60-92%) and ilmenite (FeTiO3-based, 35-65% TiO2), and
most of them are mined in Australia and South Africa. The 2003 world production of mineral rutile
(containing highest amount of TiO2 among aforementioned TiO2-related minerals) was 346,000 tons.
Although the price of TiO2-related ores have not fluctuated so much for these three years, that of
high-purity TiO2 (Produced from these raw ores) tends to increase due to its activated demand. The
world demand of TiO2 in FY2004 is estimated to be 4,267 kt, and will be increased by 5-7% (in price)
compared with 2003 (about $7.8 billion). Currently, a large portion of TiO2 is used in pigment,
however, other value-added uses such as photocatalysts have been extensively studied. The demand
for value-added products with reduced cost is desired. In this report, current status of Australian
mines, natural rutile production, price and quality trend, and our recent nanomaterial development are
demonstrated.
Effects of Sn2+ Co-Doping on the Photoluminescence of Eu3+ Ion in Strontium Phosphate
Authors: Lu Chung Hsin , Natarajan V.
Published: March 2009

The emission of Sn2+ ion can vary from blue to red depending on its co-ordination number
in the host lattice. Since Sn2+ ion has strong absorption in the ultra-violet region and can act as a
reducing agent, it is of interest to examine the effects of co-doping Sn2+ ions on the luminescence
properties of Eu3+ ions in different inorganic phosphor materials. In the present work, Eu3+ and Sn2+
ions co-doped strontium phosphate phosphors were synthesized via a solid-state reaction method in
air, argon and reducing atmosphere. The prepared samples were characterized via X-ray diffraction. It
was observed that the prepared Eu3+-doped strontium phosphate phosphor material had enhanced
Eu3+ emission upon excitation with 395 nm light.
Sealing Behavior of Visco-Elastic Composite Seals for SOFC Applications
Authors: Lee Jae Chun , Park Sung , Yu Jun Suh , Lee Jong Ho , Kim Joo Sun , Lee Hae Won
Published: March 2009

Porous composites containing ceramic fiber have been developed for the fabrication of SOFC seals. They were fabricated using glass powder and alumino-silicate chopped fibers. Effect of mixing ratios of ceramic fiber and glass on the leak rates and strength of the composite seals was investigated. In addition, seal performance of commercial glasses was compared with that of SiO2-BaO-B2O3 glass synthesized in this work. The leak rate of the composite seals containing 55 vol% glass was seven times higher than the one containing 75 vol% glass. The flexural strength of the composite seals was reduced to one fourth of the initial value as the porosity increased from 1 to 29%. The incorporation of alumino-silicate chopped fibers into a sealing glass degraded room temperature strength and increased leak rates due to increase in porosity with increasing fiber content. The viscosity of glass at the seal test temperature is presumed to affect the leak rate of the glass seal.
Size Dependence of Dielectric Properties for Barium Titanate Nanoparticles Prepared under Various Vacuum Atmospheres
Authors: Wada Satoshi , Ohishi Masanori , Takizawa Kayo , Hoshina Takuya , Kakemoto Hirofumi , Tsurumi Takaaki
Published: March 2009

Barium titanate (BaTiO3) fine particles were prepared using the 3-step thermal decomposition method of
barium titanyl oxalate under various vacuum atmospheres. In this method, the first two steps prepared
BaTiO3 nanoparticles with 30 nm, and at the 3rd step, BaTiO3 nanoparticles were heat-treated at various
temperature and degree of vacuum. As a result, as degree of vacuum is high, particle size of BaTiO3 fine
particles decreased. Moreover, the dielectric constant of BaTiO3 fine particles was measured using the
powder dielectric measurement method with slurry. The dielectric constant of these particles showed the
dielectric maximum of 4,320 at 200 nm despite degree of vacuum. This result revealed that degree of
vacuum during particle growth of BaTiO3 particles had no relation about dielectric constant.
Piezoelectric Properties in Textured Ceramics of SrBi2Nb2O9
Authors: Sawada Takuya , Ogawa Hirozumi , Kimura Masahiko , Shiratsuyu Kosuke , Ando Akira
Published: March 2009

A study has been done for the piezoelectric properties in texured ceramics of SrBi2Nb2O9 (SBN) fabricated by the templated grain growth (TGG) method. Remanent polarization along to the stacking direction increased with the orientation degrees. That corresponds to the increases in electro-mechanical coupling coefficient with orientation degree. The temperature coefficient of the resonant frequency (TCF) in thickness sheer vibration mode changed from negative to positive with increasing orientation degrees, and an excellent TCF of -0.4 ppm/°C was obtained for the specimen with an orientation degree of 76%.
Effect of Lanthanum Oxide Addition on Dielectric Loss and Microstructure of AlN Ceramics
Authors: Kume Shoichi , Yasuoka Masaki , Watari Koji
Published: March 2009

The effect of sintering additives on dielectric loss tangent and microstructure of AlN ceramics have
been investigated. Different amounts of Y2O3 and La2O3 were added as sintering additives to AlN
powder and pressureless sintering was performed at 1900 °C for 2 h in a flowing nitrogen
atmosphere. Bulk densities of sintered AlN were found to be 3.27 and 3.32 Mg·m-3 when Y2O3
contents were 0.5 and 1 mol%, respectively. The bulk densities of AlN-Y2O3 increased with
increasing La2O3 content. Densities of 3.41 and 3.42 Mg·m-3 were obtained for 0.5 mol%Y2O3-1
mol%La2O3-AlN and 1 mol%Y2O3-1 mol%La2O3-AlN ceramics respectively. A decrease in tan δ
was observed with increase in La2O3 content and a minimum value of 1.3 x 10-3 was obtained for
0.5 mol%La2O3-1 mol%Y2O3-AlN ceramic in the present study.
Preparation of Epitaxial LiTaO3 Thin Films by Metal Organic Chemical Vapor Deposition and its Electrical and Optical Properties
Authors: Yamamoto Takeki , Wakiya Naoki , Mizutani Nobuyasu , Shinozaki Kazuo
Published: March 2009

Epitaxial LiTaO3 thin films were deposited on epitaxial Pt(111)/Al2O3(001) and Al2O3(001)
substrates by metal organic chemical vapor deposition using LiTa(OC2H5)4(OC2H4OCH3)2 and
Li(DPM) precursors. The full-width at half-maximum of the rocking curve of LiTaO3 thin films were
respectively 0.29° on Al2O3(001) substrates and 0.98° on epitaxial Pt(111)/Al2O3(001). Electrical
measurements showed that the remanent polarization and coercive field of the films were 2Pr=76
μC/cm2 and E
=130 kV/cm, respectively. The leakage current density was 10-6–10-8 A/cm2 at 120
kV/cm. Refractive indices n measured at 632.8 nm were measured respectively as 2.15 on Al2O3(001)
and 2.14 on Pt(111)/Al2O3(001).
Effect on Crystal Orientation on Residual Stress and Electrical Properties of a PZT Thin Film Deposited on Buffered-Si Substrate
Authors: Fujito Keisuke , Wakiya Naoki , Kiguchi Takanori , Mizutani Nobuyasu , Shinozaki Kazuo
Published: March 2009

Changes of residual stress and electrical properties were examined in (001)-oriented and
(111)-oriented Pb(Zr0.5Ti0.5)O3 (PZT) thin films deposited on a buffered-Si substrate with a buffer and
bottom electrode layer of a (La,Sr)CoO3(LSCO). A (001)-epitaxial PZT film was prepared on
LSCO/CeO2 /Zr0.85Y0.15O1.93(YSZ)/Si. In addition, a (111)-oriented PZT film was prepared on
LSCO/SrTiO3(ST) /Mn0.24Zn0.09Fe2.67O4(MZF)/YSZ/Si. The residual tensile stress in (001)-PZT thin
films decreased from 2.92 to 1.98 GPa and the remanent polarization increased from 7.5 to 41.7
@C/cm2 as the LSCO thickness increased. In (111)-PZT, the residual tensile stress decreased from
1.72 to 0.95 GPa and remanent polarization increased from 9.5 to 26.7 @C/cm2. The residual tensile
stress of (111)-PZT was less than that of (001)-PZT. The remanent polarization in the 80 nm
(111)-PZT was greater than that of the 60 nm (001)-PZT. In the 700-nm-thick PZT, the remanent
polarization in (001)-PZT was greater than that in (111)-PZT.
Development of a Portable Electronic Nose System to Analyze Flavour Signal Patterns of Kochujang
Authors: Lee Jeong Woo , Shin Dong Wha , Kim Seong Min
Published: March 2009

The purpose of this study is to develop a portable electronic nose system to measure volatile components of agricultural and food products. Also, operating software to control the electronic nose system through the Internet was developed. Various experiments to find optimum operating conditions of the system were performed. An array of commercial metal oxide gas sensors was used to detect various gas components. For kochujang experiment, flavour signal patterns were different to the type of kochujang. Transient and steady state signals were analyzed. Transient signal analysis was more useful in PCA. Cluster analysis showed the possibility of reduction of the number of sensors. It is feasible to optimise the kochujang making process.
A Comparative Study on the Vibration Signal-Based Damage Detection for Rotor-Bearing System in Speed-Up Process:The Feature Extraction Approach
Authors: Kim Bong Suk , Lee Soo Hun , Ni Jun , Song Jun Yeob
Published: March 2009

The goal of system monitoring and diagnostics is to minimize economic losses, to increase
stability, to maximize productivity, and to maintain product quality in manufacturing. The feature
extraction from the signals acquired in rotating machine is required for performance evaluation,
condition monitoring, and fault diagnostics. In this paper, we extracted the distinctive features from
vibration signals gathered in rotor-bearing system during acceleration in order to monitor an abnormal
condition by using various kinds of signal processing methods such as the Fast Fourier Transform,
Short-Time Fourier Transform, Wigner-Ville Distribution, and Discrete Wavelet Transform.
An Impact Source Localization on a Spherical Shell by Using Smoothed Wigner-Ville Distributions
Authors: Park Jin Ho , Kim Yang Hann
Published: March 2009

A technique to localize an impact source for an elastic spherical shell is proposed. The
conventional source localization techniques when the source is located on a dispersive medium, require
both the time-of-arrival differences (TOADs) between the transducer signals and the group velocities. In
practice, the material properties or the geometry of the medium are not fully informed, therefore the
group velocity is not available. Furthermore, they are only applicable if we have a high signal-to-noise
ratio (SNR). In this paper, we propose a method that can be applicable in practice, which does not need
to know the group velocity, when we have a relatively small SNR. The scanning procedure over the
structure to acquire a minimum variance point of the estimated group velocities is suggested. To reduce
the noise effect, an exponential function is asymmetrically weighted in smoothed Wigner-Ville
distributions (WVDs). Experiments have been conducted to confirm the validity of this method. As a
result, the proposed technique is found to be effective for an impact source localization for a spherical
shell without prior information on the group velocity, even in a noisy environment.
Determination of Principal-Stress Directions by Three-Step Color Phase Shifting Technique
Authors: Pinit Pichet , Susumu Tobita , Umezaki Eisaku
Published: March 2009

A three-step phase shifting approach for automatic determination of the isoclinic parameter in photoelasticity is presented. Unreliable isoclinic values affected by the isochromatic parameter are solved using the white light. The method uses three fringe images digitally captured by a digital camera for three different configurations of the dark-field plane polariscope. For a circular disk under compression, results show the method permits the isoclinic parameter in the range -π/2 to π/2 with almost free of the isochromatic parameter and comparable with theory.
Analysis of Residual Stress in Thin Film Using Laser Scanning Method
Authors: Lee Sang Soon , Yi Mi Hie
Published: March 2009

The residual stresses in a polymeric thin film deposited on Si wafer induced during cooling from a cure temperature down to room temperature are investigated. The laser scanning method and the boundary element method (BEM) are employed to investigate the residual stresses. A 3 μm thick polyimide film is deposited on a relatively thick Si wafer. The normal stress across thickness of the thin film is estimated from wafer curvature measurements to be 20MPa . The boundary element method is employed to investigate the whole stresses in the film. The numerical result for the normal stress across thickness of the film, σ xx , shows good agreement with the experimental result obtained by using the laser scanning method. The singular stress is observed near the interface corner. Such residual stresses are large enough to initiate interface delamination to relieve the residual stresses.