bluuebunny/crossref_metadata_2025 huggingface dataset:
Specimen Design for IFSS Measurement in Fiber Pullout Test
Authors: Dai Ying , Ji Xing , Ye Lin , Mai Yiu Wing
Published: March 2009

Since stress singularity was found at the interface end in current specimen of pullout test, interface shear strength (IFSS) obtained from the tests loses its rationality [2]. But a useful conclusion [2] is that when the wedge angle of the matrix is less than a critical angle, the singularity of stress field at the interface end of the specimen in micro-debond test nearly disappears. Following this conclusion, a conic specimen shown in Fig. 1 is presented, in which the wedge angle
of the specimen is designed to be less than a critical angle in order to prevent the singular stress field occurred at the interface end. The conic specimen is designed for pullout test to avoid disadvantages inherent in the micro-debond test [3]. An axisymmetric model of fiber/matrix system with arbitrary wedge angles at the interface end is used for the determination of critical wedge angle.
With the aid of asymptotic analysis and variable separation, eigenvalue, λ, could be determined by a characteristic determinant. For a given fiber-matrix system, a curve representing the relationship between the stress singularity index and wedge angle could be obtained by solving the characteristic determinant. We define the critical wedge angle, θcr, as the corresponding singularity index of – 0.005. The design of a conic pullout specimen is also discussed. FEM analysis is adopted to
calculate the distribution of interfacial stresses near the interface end with different wedge angle. The results verify the rationality of the principle of the design of conic pullout specimen for IFSS measurement.
Atomistic/Continuum Transition – the Concept of Atomic Strain Tensor
Authors: Pyrz Ryszard
Published: March 2009

A new atomic strain concept is formulated that allows calculation of continuum quantities directly within a discrete atomic (molecular) system. The concept is based on the Voronoi tessellation of the molecular system and calculation of atomic site strains, which connects continuum variables and atomic quantities when the later are averaged over a sufficiently large volume treated as a point of the continuum body. The atomic strain tensor is applied to investigate interfacial properties of polymer based nanocomposites.
Near-Tip Fields for Penny-Shaped Cracks in Magnetoelectroelastic Media
Authors: Wang Bao Lin , Mai Yiu Wing
Published: March 2009

This paper solves the penny-shaped crack configuration in transversely isotropic solids with coupled magneto-electro-elastic properties. The crack plane is coincident with the plane of symmetry such that the resulting elastic, electric and magnetic fields are axially symmetric. The mechanical, electrical and magnetical loads are considered separately. Closed-form expressions for the stresses, electric displacements, and magnetic inductions near the crack frontier are given.
The Microstructure, Mechanical and Dielectric Properties of CNTs/Mullite Ceramics Composites
Authors: Wang Jing , Kou Hua Min , Pan Yu Bai , Guo Jing Kun
Published: March 2009

Carbon nanotube-mullite (Al2O3/SiO2=3/2) composites have been prepared by hot-pressing the corresponding composite powders, in which the multi-walled carbon nanotubes(1~10 vol%) are homogeneously dispersed between the mullite grains. The microstructure of the specimens has been studied and discussed in relation to the properties of the matrix, the bending strength and the fracture toughness, the dielectric constant and the dissipative factor. Carbon nanotube-mullite composites are potential electromagnetic wave absorbers owing to the percolation of the carbon nanotubes.
Electronic Properties of Wires Fabricated via Dielectrophoresis of Colloidal Gold Nanoparticles
Authors: Oliver Derek R. , Harrower C.T.
Published: March 2009

Gold nanoparticles were fabricated via the precipitation of gold that follows the reduction of tetrachloroauric acid in the presence of a ligand such as citric acid. Synthesis and stabilization of gold nanoparticles has been achieved in a variety of solution environments whose character ranges from polar (water) to non-polar such as dodecane. The size of the nanoparticles was measured through Mie theory analysis of extinction of UV-visible spectra and transmission electron microscope (TEM) images of particles dried onto a TEM grid. Successful mechanical ‘break-junction’ experiments in air and in the colloidal solutions demonstrate that the lowdimensional transport character observed in such experiments is not significantly affected by the solution/environment. Evidence has been obtained that, at and near the time of formation, the dielectrophoretically-grown wires formed within these colloidal suspensions have similar electrical transport characteristics to those found in mechanical break junctions.
Effect of Particle Size Distribution and Sedimentation Behaviour on Electrophoretic Deposition of Ceramic Suspensions
Authors: Bonnas Sylvia , Tabellion Jan , Haußelt Jürgen
Published: March 2009

By systematic interaction of sedimentation and electrical field in electrophoretic deposition the particle size distribution of the deposited green body can be influenced. This can be employed for producing coatings with a very smooth surface by deposition of only the nanosized fraction of a conventional powder with broad or non-monomodal size distribution, thus avoiding preceding classification. In this paper, the preparation of stabilised slurries is described focussing on the criteria particle size distribution, zeta-potential and sedimentation behaviour. The effectiveness of the interaction of sedimentation and electrophoretic deposition is to be shown.
Thermal Characteristics of the Headstock System on the NC Precision Lathe
Authors: Guo C. , Sun Qing Hong
Published: March 2009

High speed and high quality precision are essential requirements of NC lathes in modern
industry. Since the heat generated from headstock system is a major factor causing machining
inaccuracy, in this work, the thermal 3D model of the headstock system is built and its thermal
characteristics are investigated using FEM. From the comparison of the numerical results with the
experiment results, it is found that the FEM predicted well the thermal characteristics of the
headstock system and the model is reliable to further optimum design of the headstock system.
The Application of FEM Technology on the Deformation Analysis of the Aero Thin-Walled Frame Shape Workpiece
Authors: Guo H. , Zuo Dun Wen , Wang S.H. , Wang Min , Xu L.L. , Hu J.
Published: March 2009

Many thin-walled structure components widely used in aero industries not only have complex structure and large size, but also need high machining accuracy. However, because of their poor rigidity, it is easy to bring machining deformation caused by the existence of the initial residual stresses, the fixing stresses, cutting forces and cutting heat. The difficulty in ensuring their machining accuracy becomes a big problem, so that how to effectively predict and control the machining deformation has become an important subject in the development and production of our national defense weapons. This paper established a 3-D Finite element model with consideration of milling forces, clamping forces and initial residual stress field. By using this model, machining deformation of thin-walled frame shape workpieces has been computed. The simulated results are compared with experimental data, and the correctness of the simulation is verified. The study is helpful to the prediction and the control of machining deformation for thin-walled parts.
Investigation on the Cutting Performance of a New Kind of Nickel-Based Super Alloy
Authors: Wang D.L. , Kong Y.Q.
Published: March 2009

The design for orthogonal cutting experiment is made according to the characteristics of a
new kind of nickel-based super alloy. The machinability of this new material in milling and drilling
operations, including cutting force and tool wear, has been researched through experiments and then
the empirical formulas of cutting force in milling and drilling have been presented. The research is
useful in selecting the tool geometry and cutting parameters for machining the new material in
practice.
ELID Grinding Based on the State Control of Passivating Films
Authors: Ren Cheng Zu , Che J.M. , Wang Tai Yong , Jin W.D. , Jin Xin Min
Published: March 2009

The state of the passivating film is a key factor affecting ELID grinding. In the paper the
state of the passivating film on the grinding wheel surface was characterized by the loop current, the
strategies actively controlling the film state, discontinuous in-process electrolyzing and intermittent
grinding were put forward, and the ELID grinding tests under the conditions of actively controlling of
the film state and the traditional dynamic balance of the film state were respectively performed and
contrasted with each other. It is indicated that by real-time monitoring of the film state with the loop
current, the film state variation could be controlled to a narrow scope with the strategies of
discontinuous in-process electrolyzing and intermittent grinding, as a result the ELID grinding kept at
a fine quality and a high efficiency.
Electronic Subdividing Method for Linear Encoder of High Speed Position Detection
Authors: Zuo W. , Zhi Jing Feng , Huang S.T. , Zhao G.M.
Published: March 2009

This paper presents an electronic subdviving method for linear encoder of high speed
position detection. The method aims to enhance the resolution of position measurement and
improve the precision of noncircular component cutting system. A 20-subdividing circuit based on
resistor chain phase shift is researched and implemented, and some key technologies are discussed.
The method is proved to be successful in raising the resolution and precision with a high speed
response. The experiment result proves that electronic subdividing method is doable and effective to
raise the resolution of the existing system.
Numerical Simulation of Machining Distortion of Residually Stressed Aircraft Aluminum Components
Authors: Wang Q.C. , Hu Xiao Dong , Li W. , Yuan Ju Long
Published: March 2009

The presence of residual stress in aircraft aluminum components can give rise to
distortion after machining. Excessive distortion may result in the rejection of a part or the need for
costly and time-consuming rework prior to placement in service. The purpose of this research was
to develop a methodology for the prediction of machining-induced distortions of residually stressed
aircraft aluminum components. Numerical simulation results show that the magnitude of machining
distortion is strongly related to the square root of Stain Energy Density W or Stress Range σ .
The experimental results demonstrate good agreement with the predicted machining distortions of
7075T73 bulkheads. It included that the original residual stress in the blocks of aircraft aluminum
component is one of key factors to cause machining distortion.
Primary Study of Polishing with Flotative Abrasive Balls
Authors: Dai Yong , Liu W.T. , Yuan Ju Long , Yu Xun Jie , Zhou Zhao Zhong
Published: March 2009

The grain size and its identity of abrasives are of high importance to obtain the
damage-free and low roughness surfaces in traditional polishing processes. The undesirable
scratches will appear on the surface of workpiece, if the grain size of abrasives is of high
decentralization, or some abnormal larger grains or impurities are interfused in polishing process.
And it is very difficult to polish curved surfaces. A new polishing technology, which is called as
polishing with flotative abrasive balls, is put forward in this paper, in order to solve the problems
mentioned above. Some primary experiments and theoretical analyses are carried out. It is found
that the contact pressure between workpiece and abrasive grains may be easily controlled, as a
result, the depth of cutting may also be easily controlled and it is not sensitive to the grain size of
abrasives. The new technology may also be used in the polishing of curved surfaces.
Recent Development of Abrasive Water Jet Machining Technology
Authors: Huang Chuan Zhen , Wang Jun , Feng Yan Xia , Zhu Hong Tao
Published: March 2009

Abrasive waterjet (AWJ) machining is a new non-conventional machining technology. Compared with other conventional and non-conventional machining technologies, AWJ offers the following advantages: no thermal distortion, small machining force, high machining versatility, etc. Therefore this technology is regarded as a high potential technology in the field of machining difficult-to-cut materials. In this paper, a comprehensive review of research situation about the cutting performance, the cutting mechanism and the measures to improve the cutting quality is given. The application of abrasive waterjet machining in turning, milling and drilling is reviewed finally.
Silicon Atomic Layer Deposition on Nanocrystalline Diamond
Authors: Wang Yan Hui , Lu Jing , Qi X.H. , Zang Jian Bing
Published: March 2009

Single-phase nanocrystalline diamond composite is very difficult to sinter because of a
huge amount of oxygen-containing and nitrogen-containing functional groups adsorbed on the
surface of nanocrystalline diamond going against the yielding of diamond-to-diamond bonding. In
this paper, silicon film was deposited on nanocrystalline diamond by means of atomic layer
deposition (ALD) using silane as precursor, which would promote the sintering of nanocrystalline
diamond as the bond. The structure and the morphology of Si-deposited nanocrystalline diamond
were thoroughly studied by X-ray diffraction (XRD), high-resolution electron microscopy (HREM)
and Fourier transform infrared (FTIR) spectra. The results confirmed that silicon film grew
uniformly on every primary particle and functional groups adsorbed on the surface of
nanocrystalline diamond were removed by this method.
Job-Shop Scheduling Method Based on Modified Immune Algorithm
Authors: Wang W.L. , Xu X.L. , Zhao Yan Wei , Guan Q.
Published: March 2009

The mechanism of vaccination was analyzed in the immune system and the improved immune algorithm for the job-shop scheduling problem was presented. The proposed method can reserve the advantage of vaccination and it is independent of the initial antibodies. Especially, the adaptive process of vaccination with the automatic pattern recognition can not only quicken the convergence of the algorithm but also overcome some deficiencies in distilling manually the transcendent knowledge of the problem. Simulation results show that it is an effective approach.
Genetic-Based Optimal Design of a PID Controller for Substrate Temperature in a HFCVD System
Authors: Song Sheng Li , Zuo Dun Wen , Bu Guang Bin , Wang Min
Published: March 2009

In large-area HFCVD system, substrate temperature is a key factor which deeply affects the
quality of diamond films. It is hard for traditional PID method to control the temperature efficiently.
This paper presents a genetic- based PID control scheme for the control of in HFCVD system.
Computer simulation and experiment on the system are performed. The results show that the
controller designed upon GAs has good dynamic quality and steady-state precision, could meet well
the need of the temperature control during depositing diamond films.
Study on Deformation Behaviors of LD31 (6063) Aluminum Alloy Sheet by Oblique Angle Laser Shock
Authors: Zhang Yong Kang , Zuo Dun Wen , Zhang Lei , Kong De Jun , Zhou Jian Zhong , Feng Ai Xin , Zhang Ling Feng , Ge Tao , Ren Xu Dong
Published: March 2009

Laser shock forming of metal sheet usually effects on the surface of work-piece in
normal direction by laser beam, and produces shock wave force which is vertical to the surface of
work-piece. But it is difficult to shock in normal direction during processing on the surface of
forming camber, so it needs to study on oblique angle laser shock processing. LD31 forging
aluminum alloy sheet is shocked by Nd-glass laser in the paper, model and mode of oblique angle
laser shock processing is found, and transmitting characteristics of plasma stress wave is
discussed. The experiment results show that the angle between input beam and sample normal is
bigger, component of forces that parallel with sample surface is bigger, the deformation
eccentricity is bigger and bigger. When the angle is bigger, the area of laser beam spot becomes
bigger too, energy density becomes smaller, deformation becomes shallower.
Study on Pre-Stress Hard Cutting of Bearing Races
Authors: Ye Bang Yan , Liu Jian Ping , Liu Xiao Chu , Zhao Xue Zhi
Published: March 2009

The analysis on load characteristics and stress state of bearing races shows that the roll path
and outside layer of a bearing race are the main part to bear the load, and that residual tensile stress is
often found on workpiece surface. For the purpose of improving residual stress state on machined
surface of a bearing race, a method of pre-stress hard cutting is put forward. In this paper, the principle
of pre-stress cutting is introduced, and method of loading stress on bearing races, together with the
calculation for pre-stress, is analyzed. A set of device with expanding mandrel for realizing the
process is designed too and an experiment of pre-stress cutting is carried out on a lathe with PCBN
tool. The experimental results show that, by using this method, we can get residual compressive stress
on machined surface layer of a bearing race and increase the quality and contact fatigue life of bearing.
The Mechanism and Experimental Study on Laser Peen Forming of Sheet Metal
Authors: Zhou Jian Zhong , Zhang Yong Kang , Zhang Xing Quan , Yang Chao Jun , Liu Hui Xia , Yang Ji Chang
Published: March 2009

Laser peen forming of sheet metal is a new plastic forming technique based on laser shock waves, which derives from the combination of laser shock processing and conventional shot peening technique, it uses high-power pulsed laser replacing the tiny balls to peen the surface of sheet metal, when the laser induced peak pressure of shock waves exceeds the dynamic yield strength of the materials, the sheet metal yields, resulting in an inhomogeneous residual stresses distribution in depth. The sheet metal responds to this residual stress by elongating at the peened surface and effectively bending the overall shape. On the basis of analyzing the mechanism of laser peen forming, the line-track-peening experiments of 45 steel sheets with 2 mm thickness were carried out; a curved sheet metal with deep layer of residual compressive stress was obtained. The preliminary experiment result shows that laser peen forming can offer desirable characteristics in shaped metals and is a valuable technique for producing components for a range of industries.
A New Fuzzy Variable Structure Control of a Type of Nonlinear Multivariable System
Authors: Wei P. , Wang Z.L. , Qiu L.H.
Published: March 2009

In order to improve the robust performance for a type of nonlinear multivariable system,
a new fuzzy variable structure control method is introduced in detail, which combined the features
of traditional variable structure control method with the advantages of the fuzzy control theory. The
present work realized the linearization of the nonlinear multivariable system, and then the new
fuzzy variable structure control method is applied to control the linearization system. The robust
experiments were carried out on the novel method. The results indicated that the required robust
performance could be achieved with high efficiency by utilizing the new method.
Influence of Tooling Parameters in High-Speed Milling of Hardened Steels
Authors: Iqbal Asif , He Ning , Li Liang , Zha W.W. , Xia Y.
Published: March 2009

Tool life, surface roughness, and cutting forces have always remained extremely important output parameters of milling process. In this paper an attempt has been presented in order to study the influence of cutter geometry and cutter coating upon these three output parameters. Series of high-speed side milling experiments were done upon hardened AISI 4340 and AISI D2 steels using coated and uncoated carbide cutters. Mechanisms of wear occurring in different tools have been described in the paper using SEM photographs and micro-analysis of the tool surface. The analysis of experimental data shows that the coated carbide cutters having high values of helix angle and small values of rake angle, in the negative range, provide the better optimization of highspeed milling of hardened steels. Results imply that tool geometry and coating are influential upon cutting forces and tool wear but not upon surface quality. Introduction of MQL in the process leads the tool to fail abruptly because of the onset of chipping.
Modelling of Fused Biconical Taper Process for Fibre Coupler
Authors: Shuai Ci Jun , Duan Ji An , Zhong Jue
Published: March 2009

Fused-taper fiber coupler is usually fabricated by using a microburner. The coupler’s
excess loss and performance repeatability are unstable. To simulate the fabrication process and to
find solution to the performance questions, A viscoelastic rheological model of fused biconical
taper process is presented by using generalized Maxwell model to simulate the viscoelastic
characteristic of fused fiberglass, and the rheological numerical analysis under the non-isothermal
condition is carried out with ANSYS software. The effect of technical parameters such as drawing
speed and fused temperature on the fabrication process is studied. Drawing speed is in direct
proportion to the maximum stress, and fused temperature affect extremely the fabrication process.
The fluctuation of fused temperature by 5 can lead to the change of maximum stress by 30%. It
is found by experiments that the flame temperature fluctuates in the range of 5-30, while the
drawing speed is rather stable. It can be reached a conclusion that it is the fluctuation of fused
temperature that induces the poor performance repeatability and unstable excess loss.
Densification and Strengthening of Tricalcium Phosphate/Titania Composite by Hot Pressing
Authors: Lee Jong Kook , Seo Dong Seok , Jung Hang Chul
Published: March 2009

Tricalcium phosphate [TCP, β-Ca3(PO4)2]/titania composite having high mechanical properties was prepared and characterized. The TiO2 and HAp powders, as starting materials, were synthesized by precipitation and hydrothermal methods, respectively. The sintered β-TCP/TiO2 composite was prepared by hot pressing at 1000°C for 30 min under the pressure of 30 MPa in N2 atmosphere or by pressureless sintering at 1200°C for 2 h in air with moisture protection. The influence of sintering condition on the microstructures and mechanical properties of the composite was investigated. During the sintering process, hydroxyapatite used as a starting material was decomposed to β-TCP and CaTiO3 at elevated temperature because TiO2 could accelerate the decomposition of hydroxyapatite. The hot-pressed composite with 98% of sintered density showed high hardnessvalue of 1080 Hv compared with the pure hydroxyapatite (600 Hv).
Bulk Consolidation of Non-Oxide Ceramic Powders Derived from Polymer Precursors
Authors: Ishihara Satoru , Nishimura Toshiyuki , Bill Joachim , Aldinger Fritz , Wakai Fumihiro
Published: March 2009

Consolidation of pyrolyzed powders has been tried by hot isostatic pressing (HIP) without sintering additives, in order to obtain dense non-oxide ceramic bulk materials derived from polymer precursors. Si1.0C1.6N1.3 ceramic powders were derived from a polyvinylsilazane polymer. The polymer was thermally crosslinked at 250oC and pyrolyzed at 1050oC under Ar atmosphere. The pyrolyzed powders were die-pressed into rectangular bars at room temperature and densified by HIP at 1400oC-900 MPa and 1500oC-950 MPa. Dense ceramic monolith, in which pores were not observed by optical microscopy, was obtained by the HIP consolidation at 1500oC-950 MPa. The microstructure of the ceramic monolith was a nano-composite structure consisted of α-Si3N4 and graphite phases. In the compression tests of the HIP-treated sample, slight plastic deformation was observed at 1400 and 1500oC in spite of high compressive stress over 1000 MPa. On the other hand, the sample showed a compressive strain of about 7% at 1000 MPa at 1600oC. The compressive strain of about 11% was achieved at 1700oC.
Fabrication of a Strontium-Doped Lanthanum Chromite (LSC) Thin Film on SUS430 Substrate
Authors: Hwang Hae Jin , Moon Ji Woong , Lim Yong Ho , Lee Seung Hun , Lee Eun A
Published: March 2009

Lanthanum strontium chromite (LSC) thin films were prepared from the solution of La, Sr,
Cr nitrates, acetylacetone and 2-methoxyethanol. Dip-coating technique was used to decompose
La0.8Sr0.2CrO3, LSC thin films. The obtained precursor solution was sufficiently spinable and dried
gel films were crystallized after heat-treating above 500°C for 2 h. The oxidation at 800°C for 40 hr
resulted in no Fe3O4 surface-insulating phase, which means that the LSC thin film would be an
effective oxidation-protecting layer of SUS430 substrate. The carbon deposited on an uncoated
SUS430 substrate was amorphous with spherical morphology. The obtained LSC thin film was found
to be very effective on preventing carbon deposition under dry hydrocarbon atmosphere.
Synthesis of Metal Oxide Hollow Nanoparticles by Chemical Vapor Condensation Process
Authors: Lee C.W. , Kim S.G. , Lee Jai Sung
Published: March 2009

The influence of reaction temperature on phase evolution of iron oxide hollow
nanoparticles during chemical vapor condensation (CVC) process using iron acetylacetonate was
investigated. X-ray diffraction (XRD) analyses revealed that three iron oxide phases (α-Fe2O3,
γ-Fe2O3, and Fe3O4) and a mixture of β-Fe2O3 and small amount of γ-Fe2O3 were synthesized at
700oC and 900oC, respectively. TEM observation disclosed that the iron oxide particles are almost
composed of hollow structured nanoparticles of 10~20 nm in size and 3~5 nm in shell thickness. This
result implies that reaction temperature determining various reaction parameters plays an important
role for the phase- and structural evolutions of iron oxide hollow nanoparticles. Especially, the
present investigation attempted to explain temperature dependence of the phase evolution of β-Fe2O3
hollow nanoparticles in association with the decomposition of iron acetylacetonate.
Shot Peening - A New Method for Improving Mechanical Properties of Structural Ceramics
Authors: Tomaszewski Henryk , Godwod K. , Diduszko Ryszard , Carrois F. , Duchazeaubeneix J.M.
Published: March 2009

Shot peening is commonly used to modify material surface layers and improve the strength of metal components. As it occurred the same technique can be applied for brittle ceramics. High compressive stresses up to 2.4 GPa were introduced into near surface region of alumina and zirconia ceramics by ultrasonic shot peening maintaining its surface integrity. Dependence between diameter of tungsten balls, treatment time (at constant mass of balls in the housing and vibration amplitude) and level of compressive stress introduced was determined for both ceramics with nano and micrograins. Coarser grained ceramics was found to be more sensible to structural changes responsible for stress creation than the smaller one. High microplastic deformation in shot peened surface layer of ceramics was observed by X-ray diffraction. An increase of hardness and surface resistance to fracture with increasing level of compressive stress was found.
Superplastic Deformation of Silicon Nitride Nanocomposite at High Strain Rates
Authors: Chihara Kentarou , Shinoda Yutaka , Akatsu Takashi , Wakai Fumihiro
Published: March 2009

High-strain-rate superplasticity and low-temperature superplasticity are favorable for
making the use of superplastic forming for engineering ceramics even more wide spread. In this
study, a silicon nitride based nanocomposite was developed for the purpose of improving the
superplasticity. An amorphous powder was prepared by mechanical alloying of silicon nitride
and metal titanium. A Si3N4-Si2N2O-TiN nanocomposite was fabricated by hot isostatically
pressing the amorphous powder compact. A compression test was performed in the temperature
range of 1573 K to 1873 K. The nanocomposite could be deformed at a strain rate of 10-2s-1,
which was more than 100 times faster than that available for conventional superplastic Si3N4 at
1873 K. Furthermore, the nanocomposite was superplastically deformed in compression at low
temperatures from 1573 K to 1673 K. The stress exponent and the activation energy of the
nanocomposite were close to those of submicron-silicon nitride.
Surface Diffusion and Incorporation Process of Adatom in Fe-Al Multilayer System
Authors: Kim Chi Ho , Kang In Yong , Chung Yong Chae
Published: March 2009

Using the ab initio pseudopotential calculations, the surface diffusion and incorporation process at the interface of Fe-Al multilayer system were quantitatively investigated. The hollow site was most stable adsorption site on both Al (001) and Fe (001) surface. The adsorption energies were 8.62 eV for Fe/Al (001) and 5.30 eV for Al/Fe (001) system. The calculated energy barriers for the surface diffusion of adatom were 0.89 eV and 0.61 eV for each system. The energy barrier for the incorporation of Fe adatom into the Al substrate was calculated to be 0.38 eV and the energy gain of the system was 0.49 eV. However, the Al adatom required relatively large energy barrier, 0.99 eV for the incorporation into the Fe substrate resulting in 0.13 eV increase in total energy of the system.
Deformation Behavior of SiO2 Doped Nanocrystalline Monoclinic Zirconia at Low Temperatures
Authors: Yoshida Michiyuki , Shinoda Yutaka , Akatsu Takashi , Wakai Fumihiro
Published: March 2009

The deformation behavior of SiO2 doped nanocrystalline monoclinic zirconia (MZP) was
studied at 1323-1223 K in compression tests. The strain rate of SiO2 doped nanocrystalline MZP was
slower than that of high-purity MZP by one order of magnitude. SiO2 doped nanocrystalline MZP
exhibited a stress exponent n ≈ 2. The apparent activation energy for the deformation of SiO2 doped
nanocrystalline MZP was characterized by a higher value than that observed for high-purity MZP.
1wt% SiO2 doped nanocrystalline MZP was deformed at constant flow stress, while the flow stress of
high-purity MZP increased significantly with the strain (strain hardening). While no grain growth
was observed after the compressive deformation of 1wt % SiO2 doped nanocrystalline MZP,
remarkable grain growth was observed after the deformation of high-purity MZP. The addition of
SiO2 into nanocrystalline MZP is effective in limiting grain growth at low temperatures
Mechanical Properties and Damage Durability of Thermal Barrier Coatings with Thermal Fatigue
Authors: Jang Hyung Jun , Kim Dong Beak , Jung Yeon Gil , Chang Jung Chel , Choi Sung Churl , Paik Ung Yu
Published: March 2009

The effects of thermal fatigue conditions on the mechanical and contact damage behavior
in thermal barrier coatings (TBCs) are investigated as functions of the bond coat thickness and the
preparation method. Three kinds of TBCs with different thickness in the bond coat are prepared by
two different methods of APS and HVOF. The static and cyclic thermal fatigues for the TBCs are
conducted at temperatures of 950 and 1100 with different dwell times of 10 and 100 hr and 10
cycles at each temperature. Mechanical properties, hardness H and modulus E, in each condition and
component are measured by nano-indentation. The contact damage behaviors are investigated by
Hertzian indentation, including the cyclic fatigue behavior on the surface of the TBCs. The TGO
formation is dependent on both temperature tested and time exposed, showing a similar effect with
the cyclic thermal fatigues. The mechanical properties of the TBCs are increased due to the
re-sintering of the top coating and the composition change of the bond coat during the thermal
fatigues. The contact damage behaviors are affected by the thermal fatigue conditions and the
fabrication method, independent of the bond coat thickness.
Quest and Evaluation of Topcoat Materials for Environmental Barrier Coatings of SiC/SiC Composites
Authors: Nakayama H. , Morishita Kohei , Ochiai Shojiro , Sekigawa Takahiro , Aoyama K. , Oi T. , Yamamoto M. , Okamura Kiyohito , Sato M.
Published: March 2009

SiC fiber reinforced SiC matrix (SiC/SiC) composites are one of the most promising
materials for high temperature structural applications such as power generation and propulsion
systems. SiC/SiC composites are, however, susceptible to accelerated attacks in water vapor
environments through oxidation and volatilization reaction. For protection from such attacks,
Environmental Barrier Coatings (EBCs) are indispensable.
We have investigated some oxides and rare-earth silicates as topcoat candidate materials for
EBCs. Topcoat materials must be stable in the high-water-vapor pressurized environments at high
temperatures. Also, it is important that the thermal expansion coefficient of topcoat materials is
similar to that of the SiC/SiC composites.
In this study, first, zirconium oxides, lutetium silicates and yttrium silicates were selected as
topcoat candidate materials. They were exposed in a water-containing atmosphere at a temperature of
1673 K for 100 h under a total pressure 0.96 MPa. Mass changes, structure of crystals and
microstructures were investigated after the exposure experiments in order to evaluate the thermal
stability of these materials. After their estimation, lutetium silicates were considered to be promising
for topcoat materials.
Then, lutetium silicates were coated as the topcoat of an EBC system on SiC/SiC composites, and
their fracture toughness and microstructures were investigated after exposure to an oxidizing
atmosphere. The evaluation results of the topcoat materials are reported in this paper.
Development of Silicon Carbide Coating on Al2O3 Ceramics from Precursor Polymers by Radiation Curing
Authors: Wach Radoslaw A. , Sugimoto Masaki , Yoshikawa Masahito
Published: March 2009

Production of reinforced surface ceramic material was investigated by radiation
curing-oxidation method. The originality of this research is to use along with polycarbosilane (PCS)
an admixture of another preceramic polymer, polyvinylsilane (PVS). PCS, PVS or their
combination in cyclohexane solution were spin-coated onto Al2O3 plates or deposited onto porous
substrate by dipping method. After radiation oxidation step, used to preserve the coat on the
substrate, a heat treatment was applied for crosslinking of the polymer. Thickness and quality of
silicon carbide (SiC) film were investigated after pyrolysis.
Local Acceleration Effects of Adatom at the Vicinity on the Surface: Case of Co Nano Thin-Films on Al Surface
Authors: Lee Seung Cheol , Kim Sang Pil , Lee Kwang Real , Chung Yong Chae
Published: March 2009

The local acceleration effects, which are peculiar phenomena during atomic scale deposition process, were investigated byMolecular Dynamics (MD) simulation. The values of local acceleration were distributed widely for various surface orientations. Deposited atoms were accelerated along the potential energy surface, and accelerated values were evidently dependent on the local configuration of the surface. In contrast, the local acceleration became negligibly small for clusters consisting of many atoms.
Laser-Assisted Synthesis of Amorphous/Pseudoamorphous GaN Thin Films and Nanostructures
Authors: Shim Seung Hwan , Koshizaki Naoto , Yoon Jong Won , Shim Kwang Bo
Published: March 2009

Amorphous/pseudoamorphous GaN was prepared by pulsed-laser ablation at room
temperature without any heat treatment. The structure and chemical composition of the specimens
were systematically investigated. Laser ablation at low Ar pressure (<50Pa) led to deposition of
smooth Ga-rich films, which is independent with laser energy. Under same pressures, as laser energy
increased, the film stoichiometry changed from Ga-rich to near stoichiometric composition. Varying
background Ar pressure strongly affected the product structure showing little effect on the chemical
composition. Under higher pressure than 100 Pa, fine nanoparticles with a size of 5 nm rather than
films were deposited on substrate due to the increased collision by plume confining. The optical
band-gap of the deposited a-GaN is 2.8 eV for thin films and 3.9 eV for nanoparticles.
Alumina-Based Nanocomposites Fabricated by a Novel Soaking Method
Authors: Leela-adisorn Uraiwan , Matsunaga Takuya , Choi Seong Min , Honda Sawao , Awaji Hideo
Published: March 2009

Nickel dispersed alumina matrix nanocomposites were fabricated using a novel soaking
method. Secondary particles were introduced into the nano-pores of a porous matrix grains by a
soaking method, such that γ-alumina powder was soaked in nickel nitrate solution under vacuum.
During pre-calcination, nickel oxide particles were created inside of the nano-pores of γ-alumina.
The alumina powders were then reduced under hydrogen atmosphere to obtain nano-sized metallic
nickel embedded in γ-alumina grains. The alumina-nickel composite powders were sintered by
pulse electric current sintering (PECS) technique with α-alumina seeds. The maximum strength of
the alumina-nickel nanocomposites was 984 MPa after sintering at 1,450 °C with α-alumina seeds,
where the specimen size was 2210 mm3. The maximum fracture toughness was 5.5 MPa·m1/2
after sintering at 1,350 °C with seeds measured by the single edge V-notched beam (SEVNB)
method.
Fabrication of Conductive Alumina by Gelcasting and Reduction Sintering
Authors: Takahashi Minoru , Adachi Koichiro , Menchavez Ruben L. , Fuji Masayoshi
Published: March 2009

In this study, we propose a new process to fabricate electrically conductive alumina by gelcasting and reduction sintering. The process used the conventional gelcasting method except for varying amounts of monomer at 2.8, 5.5, and 8.0 wt.% relative to the weight of the slurry. In the plastic mould, the slurry was under in situ solidification for 3 hrs at 25oC to achieve gelation. The freshly gelled bodies were demolded, carefully dried, and then sintered at 1100oC, 1300oC, and 1550oC in nitrogen atmosphere. The holding times at 1100oC and 1300oC was 2 hours, while at 1550oC were 2, 4, and 6 hrs. The sintered alumina body was characterized by electrical property, X-ray diffraction, and scanning electron microscopy. Results showed that monomer additions and sintering schedule significantly affect in lowering electrical resistance. The low value was 3.6×106 +cm at 8.0wt.% monomer addition and sintering at 1550oC for 2 hrs. The effect of physical properties on electrical conductivity and the corresponding reaction mechanism were discussed in details.
Fabrication of Yttria Stabilized Tetragonal Zirconia Polycrystals Containing TiNi Intermetallic Compounds
Authors: Tanaka Norihito , Sekino Tohru , Kusunose Takafumi , Wang Hao , Nakayama Tadachika , Niihara Koichi
Published: March 2009

3Y-TZP/TiNiCo composites have been successfully fabricated by three step heating
(dehydrogenation, hydrogen reduction, hot-pressing) of 3Y-TZP /NiO/TiH2/CoO powder mixtures.
XRD analysis revealed that TiNi-base intermetallic compounds such as Ni4Ti3, NiTi, Ni3Ti had
formed. The bending strength of 3Y-TZP/TiNiCo composites (~650 MPa) were much higher than
those of 3Y-TZP monolith (350 MPa) sintered at the same condition. The electrical resistivity
characteristics indicated that 3Y-TZP/30 vol%TiNiCo composites were good electrical conductors.
Cobalt addition to TiNi phase influenced on electrical properties of final composites, while their
fracture strength was unchanged by the Co addition.
Fabrication of Large Ceramic Components with Controlled Microstructure by Powder Thermoset Molding
Authors: Lee Hae Won , Kim Joo Sun , Lee Jong Ho , Song H.
Published: March 2009

Thermoset molding in wet and dry state was successfully employed to fabricate high
strength reaction bonded silicon carbide (RBSC) ceramics. Granule transfer molding (GCM) was
developed to prevent segregation of component particles and binder phase in wet state, while granule
compression molding was applied in dry state to fabricate green compact with significant variation of
compaction ratio. Low-fill density granules with mixing homogeneity were critical for promoting
lateral deformation of granules during consolidation. In addition, anodic performance of Ni-YSZ
anode was significantly enhanced by replacing solid fugitive phase with viscoelastic fugitive phase
used as binder in thermoset molding.
Fabrication and Characterization of Zeolite-Carbon Composite from Industrial Wastes
Authors: Gao N.F. , Watari Koji , Kume Shoichi
Published: March 2009

Industrial wastes have exerted high loads on environment in view of the difficulties to
reserve landfill space and the risk of air pollution. In this study we proposed a method of
simultaneous disposing of inorganic waste and common organic waste, in light of cascade recycling
concept. Zeolite-carbon composite was synthesized by a combination of calcinations and
hydrothermal treatment of coal fly ash and sawdust mixtures. The microstructure, phase
compositions and electromagnetic wave absorption properties of the composite were evaluated. The
results showed that the low cost composite has the potential to be used as high value-added
humidity-controlling building material with the ability to absorb electromagnetic wave.
Application of Zeolites on Cellulose Fiber
Authors: Lim Hyung Mi , Jung Ji Sook , Kim Bong Young , Lee Seung Ho
Published: March 2009

Zeolites with different sizes and structures were applied on the surface of cellulose fibers
with organic and inorganic binders. The effects of zeolite structure and size and choice of binder on
the deodorization rate have been studied. The smaller the particle size, the more effective the
deodorization rate of both the zeolite coated cellulose fibers and the powder itself. The deodorization
rate depends on both the type and amount of inorganic binder. A silica based inorganic binder
revealed higher efficiency on deodorization than silicate based inorganic binder and also higher than
organic binders.
Sol-Gel Preparation and Characterizations of Europium-Ion Doped Barium Magnesium Aluminate
Authors: Lu Chung Hsin , Huang Chien Hao , Chen Chung Tao , Wang Sheng Min , Huang Shu Jiuan , Zhang Dorcas , Kadam Ramakant
Published: March 2009

The photoluminescent properties of BaMgAl10O17: Eu2+ synthesized via a sol-gel process
employing citric acid (CA) and ethylene glycol (EG) were investigated in this study. The
photoluminescence intensity of Eu2+ emission increased with increase in the doping concentration
of Eu2+ up to 15 at %. The photoluminescence intensity of BaMgAl10O17: Eu2+ also varied with the
EG: CA ratio. SEM investigation indicates that the sol-gel derived particles exhibited an irregular
shape. The EPR studies showed that Eu2+ ions occupied the sites with non-cubic symmetry in the
prepared phosphors.
Damping Properties of Vacuum Annealed and H-Doped NiTi Based Alloys at Low Stress Amplitudes
Authors: Coluzzi B. , Biscarini A. , Mazzolai Giovanni , Mazzolai Fabio M. , Tuissi Ausonio , Villa Elena
Published: March 2009

The internal friction (IF) and the Young’s modulus (E) of NiTi based alloys have been
investigated at 1 Hz and 1 kHz frequencies after various sequences of thermo-mechanical
treatments and hydrogen-doping given to the materials. Differential scanning calorimetry (DSC)
has also been used as a complementary investigation tool. Apart from the transient effects, only
occurring at 1 Hz frequencies, the data indicate a substantial insensitivity of damping to frequency.
The results show that the H-Snoek and the H-twin boundary relaxations get their maximum height
for H contents nH (nH=H/Me) equal to about 0.025 and 0.008, respectively. At kHz frequencies the
IF peaks associated with these relaxations occur at around room temperature in the Ni49Ti51 and
Ni30Ti50Cu20 alloys. Thus, these appear to be the most promising materials for applications aimed at
the reduction of vibrations.
High Frequency Dielectric Mapping Using Un-Contact Probe for Dielectric Materials
Authors: Kakemoto Hirofumi , Nam Song Min , Wada Satoshi , Tsurumi Takaaki
Published: March 2009

The microwave reflection intensity was measured at room temperature for Cu-plate, Al2O3 and SrTiO3 single crystals using a un-contact probe as a function of distance between sample and probe. The difference of reflection intensity for Cu-plate, Al2O3 and SrTiO3 single crystals was observed in the region where the distance of 0.2mm between sample and probe, and it was caused from dielectric permittivities of samples. The reflection coefficient of sample was estimated in comparison with results of electromagnetic simulation using finite differential time domain method. The reflection intensity for Cu-plate, Al2O3 and SrTiO3 single crystals was transformed to dielectric permittivity at reflection intensity minimum point. The dielectric permittivity mapping was also examined at reflection intensity minimum point.
Effect of Powder Properties of Dielectric Filler on the Dielectric Properties of a Ceramics-Polymer Composite
Authors: Kanada Isao , Sakamoto Norimasa
Published: March 2009

Effects of powder properties of the filler, including the particle size, the specific surface area and the lattice
strain on the dielectric permittivity and Q of the ceramics-polymer composites were investigated in order to
achieve composites with high dielectric permittivity and Q. The dielectric properties of the composites were
strongly influenced by the powder properties of the filler, despite that the fillers have the same composition.
Generally, lower specific surface area and lower lattice strain of the filler lead to higher Q of the composites.
In Situ Simultaneous Observation of Phase Transition and Electrical Properties of Pb(Zr,Ti)O3 Thin Film by High Temperature XRD and Electrical Measurement Apparatus
Authors: Onoue Toru , Wakiya Naoki , Seo Koichi , Kiguchi Takanori , Mizutani Nobuyasu , Shinozaki Kazuo
Published: March 2009

Pb(Zr0.05Ti0.95)O3/(La,Sr)CoO3 thin films were prepared by pulsed laser deposition (PLD) on
SrTiO3(001) substrates. Phase transition behavior of Pb(Zr0.05Ti0.95)O3 (PZT) was investigated using
high temperature X-ray diffraction (HT-XRD) and high-temperature electrical measurement. The
phase transition temperature of PZT thin film is larger than bulk one. In 100 and 200nm-thickness
epitaxial PZT thin films, the phase transition temperatures obtained from X-ray diffraction
measurement and electrical property measurement are in good agreement.
A Flat-Panel X-Ray Imaging Module for Medical Imaging and Nondestructive Testing
Authors: Cho Hyo Sung , Choi Sung Il , Lee Bong Soo , Kim Sin
Published: March 2009

In this study, we designed a flat-panel digital X-ray imaging module based upon the
amorphous silicon (a-Si) technology and tested potential for medical imaging and nondestructive
testing. The module employs a commercially available a-Si photosensor array of a 143 μm x 143 μm
pixel size and a 42.9 cm x 42.9 cm active area, coupled with a CsI(Tl) scintillator of a 550 μm
thickness, and a readout IC board which can be accessed through our home made GUI software. The
experimental test was performed to evaluate the system response with exposure, modulation transfer
function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE).
Assessment of Muscle Spasticity by a Simple Pendulum Test and Modeling
Authors: Jun Jae Hoon , Kong Se Jin , Kim Chul Seung , Eom Gwang Moon , Lee Soon Hyuck , Hase Kazunori
Published: March 2009

The quantitative and objective evaluation of spasticity is desirable in rehabilitation and
orthopedics where subjective evaluations are mostly used. In the present study, data from a simple
pendulum test are used for the evaluation of the spasticity with the help of biomechanical modeling.
The spasticity of a knee joint is modeled as nonlinear feedback of muscle lengthening velocity and the
muscle length. Through the optimization of the modeling error, the feedback parameters are
determined. The threshold of muscle lengthening velocity in the reflex system is suggested as a
severity index of the spasticity.