bluuebunny/crossref_metadata_2025 huggingface dataset:
Abnormal Grain Growth of Fe-3%Si Steel Approached by Solid-State Wetting Mechanism
Authors: Ko Kyung Jun , Cha Pil Ryung , Park Jong Tae , Kim Jae Kwan , Hwang Nong Moon
Published: March 2009

Abnormal grain growth (AGG) takes place in many metallic systems especially after
recrystallization of deformed polycrystals. A famous example of AGG in metallic system is the Goss
texture in Fe-3%Si steel. During high temperature annealing of Fe-3%Si sheet, a few near Goss {110}
<001> grains grow exclusively fast and consume the matrix grains. Therefore, the grains which have
near Goss orientation have special advantage over other grains. As a new approach to the growth
advantage of AGG, we suggested the solid-state wetting mechanism, where a grain wets or penetrates
the grain boundary or the triple junction of its neighboring grains. The solid-state wetting mechanism
for the evolution of the Goss texture in Fe-3%Si steel was studied experimentally and by phase-field
model (PFM) simulation.
Fabrication of OTFT Array with Coated Thin Film Dielectric and Printed Electrodes by Using Microcontact Printing
Authors: Jo Jeong Dai , Lee Taik Min , Kim Chung Hwan , Kim Kwang Young , Lee Eung Sug , Esashi Masayoshi
Published: March 2009

The gate, source, and drain electrodes of organic thin-film transistor(OTFT) to use as a
switching device for a flexible display was fabricated in microcontact printing process with hard
poly(dimethylsiloxane)(h-PDMS) stamp. The OTFT with thin-film dielectric layer of
parylene-C(4300Å, 5000Å, 6500Å, 7500Å, and 9000Å) were formed using special coating system,
and organic semiconductor layer was ink-jet printing process at room temperature. The microcontact
printing process using self-assembled monolayer(SAM) and h-PDMS stamp made it possible to
fabricate OTFT with channel length down to 600nm, fabricated thin film electrode of Au/Cr
(100nm/5nm), and reduced the fabrication process by 20steps compared with photolithography
process. Since the fabrication process was done in room temperature, there was no appeared such as
pattern shrinkage, pattern transformation and bending problem.
Synthesis and Characterization of Y3Al5O12 Nanocrystals
Authors: Bartwal K.S. , Kar S. , Kaithwas N. , Deshmukh M. , Dave M. , Lalla N.P. , Ryu H.
Published: March 2009

Y3Al5O12 (YAG) is one of the important and extensively used solid state laser host
materials. YAG nanocrystals were synthesized by low temperature glycol method. This is a
modified sol–gel method performed at low temperature that consists of a mixture of salts, mostly
nitrates in an aqueous media. Single phase nanocrystalline YAG was obtained at 850 °C, which is
lower temperature compared to the other methods such as wet-chemical method. This is however,
little higher than the material made by alkoxide sol–gel process. The structural characterization is
done by powder XRD, SEM and TEM techniques. The crystallite sizes range from 20-50 nm for the
materials prepared at 850- 950 °C.
Crystal Growth in Amorphous Binary Alloys of Zr-Ni System
Authors: Fukami Takeshi , Noda I. , Asada M. , Okai D. , Yamasaki T.
Published: March 2009

A crystallization process in an amorphous state under isothermal condition is examined
for binary alloys ZrNi and ZrNi2 by differential thermal analysis (DTA). Time dependence of DTA
curves is measured at several constant temperatures just below crystallization temperature. The
fraction of crystallized volume in amorphous state and its time evolution during isothermal
annealing are measured. These data are analyzed by the Johnson-Mehl–Avrami formula. The
Avrami exponent is 2.4±0.1 for ZrNi and 3~4 depending on the set temperature for ZrNi2. The
activation energy for crystallization of amorphous ZrNi and ZrNi2 was estimated by plots of lnt1/2
vs. 1/T.
Y-Shaped Carbon Nanowires Obtained from Ethanol Flames and their Growth Mechanism
Authors: Cheng Jin , Zou Xiao Ping , Li Fei , Zhang Hong Dan , Ren Peng Fei , Zhu Guang , Wang Mao Fa
Published: March 2009

Y-shaped carbon nanowires as a multi-branched carbon nanostructure have potential
applications in electrical nano-devices. In this paper, we report the synthesis of Y-shaped carbon
nanowires obtained from ethanol flames. These Y-shaped carbon nanowires have different
morphologies from one to another. It is interesting that there are two Y-junctions on individual
carbon nanowires. According to our experimental results, the growth mechanism of Y-shaped carbon
nanowires has been discussed and a possible growth model of these Y-shaped carbon nanowires has
been proposed.
Comparison between Tribological Characteristics of Al-Cu-Fe-B Quasicrystalline and Mo Coatings
Authors: Kim Bong Hwan , Lee Sang Mok
Published: March 2009

Al-Cu-Fe-B quasicrystalline and Mo coatings were obtained on the mild steel and brass
substrates by thermal spraying routes for the purpose of replacement of Mo coatings with
quasicrystalline ones. Quasicrystalline coatings were prepared by air plasma spraying and/or HVOF
(High Velocity Oxygen Fuel) techniques followed by subsequent heat treatment, and Mo coatings,
wire flame spraying. For comparative studies of important properties for industrial application,
mechanical properties, bonding strength, surface energy, and tribological behavior were investigated
based on microstructural characterization. Basic mechanical properties such as hardness, fracture
toughness, and elastic modulus of quasicrystalline coating showed comparable values with those of
Mo coatings. De-bonding tests of coatings deposited onto brass substrate indicated that the bonding
strength of quasicrystalline coatings obtained by HVOF techniques exhibit higher value to Mo
coatings. Non-sticking property analogized from surface energy calculation and friction coefficient of
quasicrystalline coatings also showed better performance during the tests. It is suggested from this
investigation that the quasicrystalline coating can be effectively used as a replacement of the Mo
coating, which has shown a recent steep price rise and problems of accidental existence of minor
environment harmful elements such as Cr6+, Pb, Cd, and Hg.
Carbon Nanotubes Obtained by ECC Technique with Cobalt Salt as Catalyst Precursor
Authors: Zhang Hong Dan , Zou Xiao Ping , Cheng Jin , Li Fei , Ren Peng Fei , Wang Mao Fa , Zhu Guang
Published: March 2009

In this paper we report the preparation of carbon nanotubes (CNTs) by ethanol catalytic
combustion (ECC) technique. We employed cobalt salt as catalyst precursors, copper plate as
substrate and ethanol as carbon source. In order to have a better understanding of the growth
mechanisms, we employed cobalt chloride, cobalt nitrite and cobalt sulfate as catalyst precursor to
study the influence of catalysts on CNTs growth respectively. Entangled and nonseparated CNTs
were aggregated together when the catalyst precursor was cobalt chloride, while straight and uniform
CNTs were obtained when the catalyst precursor was cobalt sulfate. In the case of using cobalt nitrite
as catalyst precursor, the CNTs tend to form helical and disordered structure. We have examined the
morphology and microstructure of the obtained CNTs and discussed the growth mechanism.
FIB and TEM Studies on the Bainitic Microstructure in Low Carbon HSLA Steels
Authors: Kang J.S. , Ahn S.S. , Yoo C.Y. , Park Chan Gyung
Published: March 2009

In the present study, focused ion beam (FIB) technique was applied to make site-specific
TEM specimens and to identify the 3-dimensional grain morphologies of bainitic microstructure in
low carbon HSLA steels such as granular bainite, acicular ferrite and bainitic ferrite. Granular
bainite consisted of fine subgrains and 2nd phase constituents like M/A or pearlite located at grain
and subgrain boundaries. Acicular ferrite was characterized by an aggregate of ramdomly orientated
and irregular shaped grains. The high angle boundaries between adjacent acicular ferrite grains
caused by intragranular nucleation during continuous cooling process. Bainitic ferrite revealed
uniform and parallel lath structure within the prior austenite grain boundaries and its’ packet size
could effectively decreased by the formation of intragranular acicular ferrite.
Magnetic and Mechanical Properties of Fe-Co-B-Si-Nb-M (M = Al, V, Mo,) Bulk Metallic Glasses
Authors: Kwon Oh Jib , Lee Young-Kook , Lee Jin Ju , Kim Yu Chan , Fleury Eric
Published: March 2009

The compositional dependency of the glass forming ability (GFA), magnetic and
mechanical properties of the Fe52Co20B20Si4Nb4 bulk metallic glass was investigated by means of
the partial substitution of Co either by Al, V or Mo elements. A minor concentration of these
elements enabled an increase of the GFA and fully amorphous rods of 4 mm diameter were
successfully fabricated for the Fe52Co19B20Si4Nb4Al1, Fe52Co17B20Si4Nb4V3 and
Fe52Co17B20Si4Nb4Mo3 alloys. While the addition of Al resulted in an increase of the magnetization
saturation, V appeared as the most effective element to enhance the plastic deformation under
compression.
High-Field Maxwell Stress Effect of Dielectric Actuator Based on Segmented Polyurethane
Authors: Lim Hyun Ok , Bark Gyeong Mi , Park Hyun , Chun Ho Hwan , Jo Nam Ju
Published: March 2009

This study dealt with the bending-electrostrictive response of segmented polyurethane
(SPU) films, which was a promising candidate for a material to be used in polymeric actuators.
Electrostriction is the phenomenon that a material is strained due to both Maxwell stress effect and
electrostriction effect developed by the applied voltage. When a dielectric material is subject to an
electric field, it will experience Maxwell stress caused by the Coulomb force between accumulated
charges and electrostriction by the reorientation of polar phase in the material. In order to SPU having
large deformation and force, SPU was composed of the soft segment with poly(tetramethylene
glycol), the hard segment with 4, 4’-diphenylmethane diisocyanate, and 1, 4-butanediol. Dielectric
actuator based on SPU had good mechanical properties, field-induced strain, and force.
Effect of Co-Doping Cation on Phase Stability of Zirconia Bioceramics in Hot Water
Authors: Yuhara S. , Takigawa Yorinobu , Uesugi Tokuteru , Higashi Kenji
Published: March 2009

Phase stability of cation co-doped zirconia ceramics is examined. As the result, in
contrast to the result in small amount of single cation doped zirconia, phase stability of co-doped
zirconia ceramics can not be simply explained from ionic radius and valency of dopant or from the
change in axis ratio. We focus on oxygen vacancy concentration and binding energy between
oxygen vacancy and doped cation. By estimating phase stability from these factors, it is found that
concentration of oxygen vacancy and the binding energy between the dopant and the oxygen
vacancy are important factors for understanding the phase stability of zirconia ceramics.
Effect of Thermo-Mechanical Processing on Texture and Elastic Modulus of Ti-Nb-Si Alloys for Biomedical Application
Authors: Kim Han Sol , Ra Tae Yeub , Bang H.J. , Yoo Young Gyu , Kim Won Yong
Published: March 2009

Microstructure and texture of Ti-Nb-Si based alloys, prepared by water quenching from
β-phase field, cold rolling and recrystallization heat treatment followed by water quenching, were
investigated in terms of optical microstructure and analysis of X-ray pole figure result. Optical
microstructure observation and X-ray diffraction analysis revealed that the microstructure of
as-quenched sample appeared to mixture appearance consisting of mostly bcc-structured β phase and
small amount of orthorhombic-structured α″ phase. After cold rolling elongated structure parallel to
the rolling direction was observed, and equiaxed structure with the average grain size of about
20~30μm was developed for the sample after recrystallization heat treatment. In as-cold rolled sample
we have found well-developed α-fiber texture components which are frequently observed in
bcc-structured metals and alloys. In recrystallized sample, rotated cube texture component was
weakly detected. The variation of elastic modulus values was interpreted in terms of changes in
texture components depending on thermomechanical processing.
Preparation of Silicon-Containing Apatite Coating on Titanium
Authors: Hashimoto Takayoshi , Obata Akiko , Kasuga Toshihiro
Published: March 2009

A silicon-containing apatite layer was prepared on a metallic titanium substrate coated
with a silica layer. The silica layer on a titanium substrate was derived from water glass through
heat-treatment at 300 °C for 2 hr and subsequent acid-treatment using 0.1 N-HCl at 50 °C for 2 hr.
The silica layer was homogeneously coated with nano-sized vaterite powders (~ 0.5 μm in diameter).
The vaterite coating was achieved by utilizing the interaction of surface potentials between the
positively charged vaterite and the negatively charged silica layer. After soaking the sample in
simulated body fluid at 37 °C for 3 days, hydroxyapatite (HA) formed on the surface of the
silica-coated titanium. The HA layer was found to include a trace amount of releasable silicon, which
may enhance the osteoblast proliferation.
AC Impedance Behaviors of Ti-Zr Binary Alloys for Biomaterials
Authors: Oh Mi Young , Choe Han Cheol , Ko Yeong Mu
Published: March 2009

In this study, AC impedance behaviors of Ti-Zr binary alloys for biomaterials have been
investigated using by electrochemical impedance spectroscopy. Ti-10wt%, 20wt%, 30wt%, and
40wt% Zr alloys were prepared by arc melting and homogenized for 24 hr at 1000 °C in argon
atmosphere. Phase constitutions and microstructure of the specimens were conducted by using XRD,
OM and SEM. The corrosion properties of the specimens were examined through potentiodynamic
test (potential range of -1500 ~ 2000 mV), AC impedance spectroscopy(100kHz~10mHz) in artificial
saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA). In as-cast and homogenized
Ti-xZr alloys, α-phase was identified by XRD. Microstructures were changed from lamellar structure
to needle-like structure as Zr content increased. From the results of polarization behavior in the
Ti-xZr alloys, it was found that the corrosion resistance was increased with increasing Zr content.
From results of AC impedance spectroscopy, passive film resistance value of homogenized Ti-40Zr
specimen(1.60×106 Ωcm2) showed higher than that of as-cast specimen.
Nano Composite Membranes of Sulfonated Poly(2,6-Dimethyl-1,4-Phenylene Oxide)/Poly(2,6-Diphenyl-1,4-Phenylene Oxide) Copolymer and SiO2 for Fuel Cell Application
Authors: Jeong Young Gi , Park Hye Seok , Seo Dong Wan , Choi Seung Woo , Kim Whan Gi
Published: March 2009

The Sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) / poly(2,6-diphenyl-1,4-phenylene
oxide) (S-PPO) was prepared by oxidative coupling polymerization with 2,6-dimethyl phenol,
2,6-diphenyl phenol, CuCl(І) and pyridine, and followed sulfonation with chlorosulfonic acid.
Copolymer was consisted of 2,6-diphenyl phenol 30 mol% and 2,6-dimethyl phenol 70 mol%.
Organic-inorganic nano composite membranes were prepared with copolymer and a series of SiO2
nanoparticles (20 nm, 4, 7 and 10 wt%). The composite membranes were cast from dimethylsulfoxide
solution. The membranes were studied by differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction
of sulfonated polymers with water and methanol. S-PPO copolymer and nano composite membranes
exhibited proton conductivities from 0.79×10-3 to 0.98×10-3 S/cm, water uptake from 21.70 to
24.77 %, IEC from 0.720 to 0.955 meq/g and methanol diffusion coefficients from 2.97×10-7 to
3.70×10-7 cm2/S.
Increase of Electrolysis Cell Performance by Addition of PVDF and Graphite Powder on MEA for Regenerative Fuel Cells
Authors: Lee Hong Ki , Hong Sung Wan , Yang Sung Won , Lee Woo Min , Yoon Jeong Mo
Published: March 2009

For the regenerative fuel cell (RFC), water electrolysis cell performance using membrane
electrode assembly (MEA) in polymer electrolyte fuel cell (PEMFC) were investigated. A part of
Nafion had been secondary sprayed on the surface of catalytic layer and variation of cell
performance was diminished. The conformation of stability, improvement of mechanical and
electrical properties was accomplished by addition of PVDF, graphite and RuO2. With the addition
of graphite power and RuO2, the voltage was decreased from 3.6V to 2.5V and 2.2V. The
improvement of the mechanical properties was obtained by addition of PVDF. The electrolysis cell
manufactured with MEA electrode was showed less decomposition voltage of 1.3V than with
Nafion electrode at 10A of applied current. The stability of MEA was confirmed from 30 days of
cell operation
Surface Fractals and Wetting Properties of Porous Anodes Strengthened by Ni3Al for Molten Carbonate Fuel Cell
Authors: Kim Yun Sung , Moon Kil Ho , Lim Jun Heok
Published: March 2009

The contact angles of pure Ni, Ni/7wt%Ni3Al, Ni/5wt%Ni3Al/ 5wt%Cr and Ni/10wt%Cr
anodes for the MCFC were measured by means of the capillary rise method in 62mol%Li2CO3+
38mol%K2CO3 and 52mol%Li2CO3+ 48mol% Na2CO3 electrolyte and at different atmosphere. Also
surface fractal dimension (Ds), which could characterize pore structure of the anodes, was
calculated from experimental data obtained by mercury porosimetry and nitrogen adsorption
method. The surface fractal dimensions of the anode were in range from 2.75 to 2.81, because
porosities of the anodes for MCFC were controlled regularly to about 62% during sintering. It was
investigated from wetting-in experiment by capillary-rise method that the contact angles between
the anodes and the carbonate electrolytes were relatively decreased at CO2 atmosphere rather than
air atmosphere and the angles were also decreased in the 62mol%Li2CO3+38mol%K2CO3
electrolyte rather than that measured and in the 52mol%Li2CO3+48mol% Na2CO3 electrolyte.
Synthesis and Decomposition of Pure Ca(AlH4)2
Authors: Morisaku Naoto , Komiya Kenji , Li Yu Zhan , Yukawa Hiroshi , Morinaga Masahiko , Ikeda Kazutaka , Orimo Shinichi
Published: March 2009

Pure Ca(AlH4)2 is synthesized and its decomposition reactions are investigated in a
fundamental manner. The XRD profile observed is in good agreement with the one reported by
Fichtner et al. From TDS measurements, Ca(AlH4)2 appears to decompose into CaH2+2Al+3H2 in
three steps. The peak temperature of the first reaction is about 470K which is higher than that for
Mg(AlH4)2 (about 450K), indicating that Ca(AlH4)2 is more stable hydride than Mg(AlH4)2. In
addition, the catalysis of TiCl3 is doped into Ca(AlH4)2 by ball milling under a hydrogen gas
atmosphere and catalytic effects on the decomposition properties are investigated.
Processing and Tensile Property of Nano Dispersed Al-Fe-(Mo, V, Zr) Bulk Alloy
Authors: Jung Taek Kyun , Kim Mok Soon , Kim W.Y. , Kwon Hyouk Chon , Yi S.
Published: March 2009

The microstructures and mechanical properties of the bulk Al-Fe-(Mo, V, Zr) alloy
produced by melt spinning process and subsequent hot extrusion at 693K in the extrusion ratio of 25
to 1 were investigated. TEM observation revealed an equiaxed grain structure with the average grain
size of 200 nm for the extruded bulk alloy. Extremely fine dispersoids based on Al-Fe phases,
Al-Fe-(Mo, V) phases and Al-Zr phases were observed to be distributed uniformly within grains and
at grain boundaries. The size distribution of the binary Al-Fe and the Al-Fe-(Mo, V) phases were
ranged from 20 nm to 50 nm, whereas the Al-Zr phase was less than 10 nm. The very high tensile
strength of about 800MPa was achieved at room temperature for the extruded bulk alloy.
Hydrogen Solubility and Resistance to Hydrogen Embrittlement of Nb-Pd Based Alloys for Hydrogen Permeable Membrane
Authors: Watanabe N. , Zhang G. , Yukawa Hiroshi , Morinaga Masahiko , Nambu Tomonori , Shimizu K. , Sato S. , Morisako K. , Matsumoto Yoshihisa , Yasuda Isamu
Published: March 2009

The alloying effects of Pd on the hydrogen solubility and the resistance to hydrogen
embrittlement are investigated for Nb-xmol%Pd-ymol%Zr (x=0~19; y=0, 1) alloys. The hydrogen
solubility at 673 K is found to decrease with increasing Pd content in the alloys. Both pure Nb and
Nb-Pd alloys possessed ductility in vacuum at 673 K. However, severe hydrogen embrittlement
occurs in pure Nb when it is tested under the hydrogen pressure even as low as 0.01 MPa. In view of
the small punch (SP) absorption energy, the addition of Pd into Nb improves the resistance to
hydrogen embrittlement by decreasing the hydrogen solubility in the alloy, although brittle fracture is
still observed in the Nb-15mol%Pd alloy tested under a hydrogen pressure of 0.015 MPa at 673 K.
Application of Open Celled Al in the Alloy Hydride System for Hydrogen Storage
Authors: Kim Il Ho , Lee Won Sik , Ko Se Hyun , Jang Jin Man , Kim Ho Sung
Published: March 2009

The open cell Al (or Al foam) was employed in the alloy hydride system due to the rapid
heat conductivity of Al. The hydrogen storage alloy powders were packed in this storage system
made of Al open cell, and the changes of temperature and equilibrium pressure of hydrogen
desorbed were measured. By applying the open cell Al in this hydrogen storage system, the reaction
sensitivity of the temperature and equilibrium pressure was far rapidly increased than that without
the open cell Al.
High-Pressure Synthesis of Novel Hydride in Ca-TM Systems
Authors: Yambe Y. , Kataoka R. , Kyoi D. , Kamegawa Atsunori , Takamura Hitoshi , Okada Masuo
Published: March 2009

Hydrogen storage materials are attracting much attention as media of storing hydrogen.
High-pressure synthesis has been widely used for exploration of novel materials. We have reported
that many new Mg-based hydrides or alloys have been synthesized by anvil-type apparatus under
the pressure of GPa-order. In Mg - TM ( TM = Nb, Ta ) - H systems, it was reported that novel
FCC-type hydride which is similar in crystal structure and composition to Mg7TiH13-16 was
synthesized under 8 GPa. On the other hand, there is few reports of novel Ca-based hydrides to be
synthesized under high pressure. However, the compressibility of calcium is higher than that of
magnesium. Thus, there is a tendency for Ca compounds to be synthesized by lower pressure than
Mg ones.
This study describes the synthesis of new Ca-based hydrides by this high-pressure techniques. In
Ca - TM ( TM = Ti, Hf, V, Nb and Ta ) systems, the influence of applied pressure on present phases
were investigated. For the composition of CaH2 - 14.3 mol%ZrH2 in Ca - Zr - H system, novel
hydride was synthesized at 1073 K for 2 h under 5 GPa. Crystal structure of the novel hydride was
found to be FCC-type with a lattice parameter of a = 0.531 nm. In addition, the thermal stability and
hydrogen contents of this novel hydride were investigated.
In Ca - Hf - H system, the unknown phase was observed in the sample of CaH2 - 12.5 mol%HfH2
prepared 1073 K for 2 h under 5 GPa. This unknown phase is FCC structure with lattice parameter
of a = 0.528(2) nm.
Application of Porous Concrete to a Structural Foundation in Soft Ground
Authors: Kim Hong Taek , Yoo Chan Ho , Hwang Jung Soon , Sim Young Jong
Published: March 2009

In this study, porous concrete is applied to the stone column, which is a structural
foundation in soft ground. The porous concrete reinforces the upper portion of the stone column and
forms a composite foundation to restrain bulging collapse. To function as a foundation material
properly in soft ground, concrete must be permeable to expel subsurface ground water outside and
have sufficient compressive strength to reduce settlement, which is a critical factor for the
foundation design. From laboratory experiments, the compressive strength increases and the
permeability decreases as the amount of cement increases. To evaluate the settlement, full-scale
tests and finite element analyses using porous concrete were performed. As a result, it was
confirmed that the use of a stone column reinforced by porous concrete was very effective in
reducing the settlement of the foundation in soft ground.
Fabrication of Magnesium Foam by Precursor Method Using Machined Chips
Authors: Mehara Kazuhito , Kobashi Makoto , Kanetake Naoyuki
Published: March 2009

The present study is aiming at investigating the possibility of producing a magnesium
foam from machined chips. To produce highly porous magnesium foam, precursor producing
process was investigated by hot extrusion and compressive torsion processing (CTP). The CTP
could realize well-consolidated precursors and homogeneous distribution of a blowing agent. The
precursor made of machined chips satisfactorily expanded, and the porosity were comparatively
high by optimizing processing parameters of the CTP.
First-Principles Study of Structural and Electronic Property of Pyrochlore Dy2Sn2O7
Authors: Chen Zhong Jun , Zu Xiao Tao , Wang X.Q.
Published: March 2009

Density Functional Theory method within Generalized Gradient Approximation has been
performed to obtain the static lattice parameters, oxygen positional parameter, bond length and bond
angle and electronic properties of ideal Dy2Sn2O7 pyrochlore. The results are in excellent agreement
with available experimental measurements. DOS of this compound was presented and analyzed. We
also notice the presence of the hybridization between oxygen and both Sn and Dy metal.
Modeling and Simulation of Driveline Test Bench for Automotive Chassis Component System
Authors: Kim Kee Joo , Kim Joo Sung , Choi Jae Wook , Ju Hyung Jun , Heon Lee Yong , Choi Byung Ik , Lee Hak Joo
Published: March 2009

Vibration in a driveline is presented in this paper. In the experiment, the rear subframe
and propeller shafts and axle were composed and mounted with rubber each other. For applying the
vibration input instead of the torsional vibration effect of an engine, the shaker was taken. In
particular, torsional vibration due to fluctuating forced vibration excitation across the joint between
driveline and rear subframe was carefully examined. Accordingly, the joint response was checked
from experiments and the FE-simulation using FRF (frequency response function) analysis was
performed. All test results were signal processed and validated against numerical simulations. In
present study, the new test bench for measuring the vibration signal and simulating the vehicle
chassis system was proposed. The modal value and the mode shape of components were analyzed
using the model to identify the important components affecting driveline noise and vibration. It
could be reached that the simplified test bench could be well established and be used for design
guide and development of the vehicle chassis components.
Numerical Simulation on Stress Fields of Lasers Braze Fusion Welding
Authors: Dong Ping , Li Rui Wen
Published: March 2009

The assembled tube was made of beryllium tube and tungsten tube, and was produced by
over fitting. The residual stresses in the assembled tube were very comprehensive after lasers braze
fusion welding, not only including the welding residual stresses, but also the initial stresses from over
fitting. Both of the dimension and strength were affected by the complex residual stress distribution in
the assembled tube. MSC.MARC software was used to simulate the stress fields during lasers braze
fusion welding of the assembled tube. The stress fields during lasers braze fusion welding and the
residual stresses after welding have been obtained, and the effect of over fitting on welding residual
stress of the assembled tube have also been studied. The residual stresses at outer surface of the
assembled tube have been measured by the X-ray diffraction method. A comparison of the residual
stresses by finite element method (FEM) to that by experiment indicates an identical stress change
trend and thus validates the FEM model.
Thermodynamic Analysis of the Ti-Zr-H Ternary Phase Diagram
Authors: Ukita Shusuke , Ohtani Hiroshi , Hasebe Mitsuhiro
Published: March 2009

A thermodynamic analysis of the Ti-Zr-H ternary system has been performed by combining
first-principles calculations with the CALPHAD approach. To enable the thermodynamic description
of the binary systems, the results from our previous evaluation were adopted for the Ti-H, Zr-H, and
Ti-Zr systems. The ternary compound, Ti2ZrH4, with an Fd3m-type crystal structure, exists over a
wide composition range, and the (Ti)2(Zr)1(H,Va)4-type three-sublattice model was applied to
describe its thermodynamic properties. Because of the lack of experimental information available, the
enthalpy of formation of the Ti2ZrH4 phase was evaluated using the Full Potential Linearized
Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type
thermodynamic analysis with some other experimental information. The calculated phase diagrams
and the hydrogen isotherms were in good accordance with previous experimental results. Our
calculations revealed that the ternary compound decomposes into a bcc and gas phase in the vicinity
of 1270 K.
Forging Process Design of Al Rotating Arm Holder by FE Analysis
Authors: Hur Kwan Do , Lee Hyo Young , Yeo Hong Tae
Published: March 2009

Aluminium alloys have been widely used in the structure of aircraft and passenger car
because of its lightweight. It is also interested in the lightweight products to improve the fuel
efficiency. In this research, forging design of Al rotating arm holder has been studied by FE
analysis. Structural analysis of the model was performed at first. From the results of the analysis,
effective stress, effective strain and safety factor acting on the component were obtained.
Friction Stir Weld Modeling of Aluminum Alloys
Authors: Cho Jae Hyung , Kang Suk Hoon , Oh Kyu Hwan , Han Heung Nam , Kang Suk Bong
Published: March 2009

Friction stir welding (FSW) process of aluminum alloys was investigated using a
two-dimensional Eulerian formulation coupling viscoplastic flow and heat transfer and strain
hardening. The thermal equation for the temperature was modified to stabilize temperature
distribution using a Petrov-Galerkin method. The evolution equation for strength was calculated
using a streamline integration method. Predicted strength was compared with experiments. Based on
crystal plasticity, texture evolution was predicted during FSW of AA6061.
Orientation Control in Multilayered Alumina Prepared Using Electrophoretic Deposition in a Strong Magnetic Field
Authors: Suzuki Tohru , Uchikoshi Tetsuo , Morita Koji , Hiraga Keijiro , Sakka Yoshio
Published: March 2009

We have reported that development of texture can be controlled by colloidal processing in
a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina, titania
and so on. We demonstrate in this study that alumina/alumina laminar composites with different
crystalline-oriented layer are produced by electrophoretic deposition (EPD) in a strong magnetic field.
This composite was fabricated by alternately changing the angle between the directions of the
magnetic and electric fields layer by layer during EPD in 12T. The grains in alternate layers are
aligned differently.
Transformation of Bone Origin Hydroxyapatite at Elevated Temperatures and in Selected Atmospheres
Authors: Haberko Krzysztof , Bućko Mirosław M. , Mozgawa W. , Pyda A. , Haberko M. , Carpentier J.
Published: March 2009

In the present work the behaviour of HAp extracted from pig bones at elevated
temperatures up to 1000oC in O2 and CO2 atmospheres has been studied. It has been found that CO2
atmosphere arrests HAp decomposition. Chemical analysis and infrared spectroscopy reveal that no
free CaO appears and no decrease of CO3
-2 concentration groups occurs in the material calcined in
CO2 atmosphere. In the O2 atmosphere at elevated temperatures CaO and CO2 are emitted from the
samples, although the remaining material retains the HAp structure as indicated by the X-ray
diffraction.
Environmentally Intelligent Biocomposites
Authors: Weal Stephanie , Anderson Sheree , Anderson Ross , Stuthridge Trevor , Fernyhough Alan
Published: March 2009

Composites made from wood residues and biomasses, together with either conventional polymers
such as polypropylene (PP) and their recyclate streams or with the new emerging biopolymers such
as polylactic acid (PLA), were compounded and injection moulded. Mechanical properties and
biodegradation analyses were undertaken. The addition of wood flour/sander dust (SD) and wood
fibres (WF), to the PP, with suitable compatibilizer, increased the flexural and tensile modulus and
strength, indicating a good bond between the fibres and matrix. The tensile and flexural strengths
were decreased with the addition of wood fillers, additives and biomasses to a PLA biopolymer
blend. Such biomasses and additives increased the biodegradation of the PLA blend, and some
control over biodegradation rates was achievable.
Intercalation of Montmorillonite by Interlayer Adsorption and Complex Formation
Authors: Pannirselvam Muthu , Gupta R.K. , Bhattacharya S.N. , Shanks Robert A.
Published: March 2009

Clays are essentially composed of crystalline particles of one or more members of a small
group of minerals. The ability of clays to intercalate certain organic substances has been known for
a very long time. There is a scope in these clay structures for isomorphous replacement, that is, for
substitution of Na+ by cations of similar size but usually of lower valency. This research aims at
identifying suitable additives for pretreatment of clay and determining the effect of different classes
of compounds (intercalants) on the d-spacing expansion of clay layers. This paper addresses a
different approach to ion exchange for treatment of sodium montmorillonite, with different
functional groups: aldehyde, ether, alcohol, glycol, and stearates. The results were compared with
commercially available clays, Cloisite 25A and Cloisite 30B (Southern Clay Products), which are
montmorillonite (MMT) clays intercalated with quaternary ammonium salts. The d-spacing
increment in this research was consistent with the d-spacing achieved in commercially available
clays. Future research will be to utilize the treated clay to produce polymer composites.
Growth and Evaluation of GaN Grown on Patterned Sapphire Substrates
Authors: Kang D.H. , Song Jae Chul , Kim Dong Wook , Kim J.S. , Santhakumar Kannappan , Lee Cheul Ro
Published: March 2009

We report the microstructure and optical properties of gallium nitride (GaN) epilayers grown on lens shape patterned sapphire substrate (PSS) using metalorganic chemical vapor deposition (MOCVD) for various growth times. A lens shaped pattern was used to reduce the threading dislocation density and to improve optical emission efficiency. A scanning electron microscope (SEM) image shows flat and smooth surface of GaN grown on PSS at 80 min which could be achieved by lateral growth from the trench region. From the DCXRD spectra, full width at half maximun (FWHM) value was decreased with increasing growth time. FWHM of the sample grown at 80 min was 473.5 arc sec. This indicates there is an improvement in crystalline quality of the GaN grown on PSS as the growth time increases. From photoluminescence (PL) spectra, an increase in band edge emission intensity and a decrease in defect related yellow luminescence was observed for GaN on PSS as the growth time increased. From the PL spectra, FWHM was 82.2 meV at peak position 363.9 nm for the sample grown for 80 min. It is clearly seen that the threading dislocations can be reduced by lateral growth improving the light emission efficiency by internal light reflection on the lens surface for GaN grown on PSS.
Characteristics Comparison between GaN Epilayers Grown on Patterned and Unpatterned Sapphire Substrate (0001)
Authors: Song Jae Chul , Kang D.H. , Shim Byung Young , Ko Eun A , Kim Dong Wook , Santhakumar Kannappan , Lee Cheul Ro
Published: March 2009

GaN epilayers were grown on lens shaped patterned sapphire substrate (PSS) (0001) and unpatterned sapphire substrate (UPSS) (0001) by metal-organic chemical vapor deposition (MOCVD). The quality of the grown GaN epilayers on the PSS and UPSS were compared. Structural characteristics, surface morphology and optical properties of the GaN epilayers were investigated using double crystal X-ray diffraction (DCXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and photoluminescence (PL). A lens shaped pattern was formed on the sapphire substrate to reduce threading dislocation (TD) density and also to improve the optical emission efficiency by internal reflection on the lens. Scanning electron microscopy images show the growth of GaN epilayers at various times. Full coalescence is observed at a growth time of 80 min. It is seen from the DCXRD rocking spectrum that full width at half maximum (FWHM) of the GaN grown on PSS was 438.7 arcsec which is less than UPSS value. The lower value of FWHM indicates that the crystalline quality of the GaN epilayers grown on PSS is improved compared to GaN grown on UPSS. It is clearly seen from the AFM images that the dislocation density is less for the GaN grown on PSS. A strong and sharp photoluminescence (PL) band edge emission was observed for the GaN grown on PSS compared to UPSS. Defect related yellow luminescence was observed for GaN grown on UPSS which did not appear for PSS. The FWHM at the 364.3 nm peak position was evaluated to be 50.7 meV from the PL spectra for GaN grown on PSS. The above result indicates GaN epilayers can be grown on PSS with low TD density and will be useful for optical emission.
Characterization of Quasi-Nano Crystalline Ni-Zn Ferrite Powders Prepared by Self-Propagating High Temperature Synthesis
Authors: Choi Y.
Published: March 2009

NixZn1-xFe2O4 ferrites with initial unit molar ratio of NiO/ZnO were prepared by
self-propagating high temperature synthesis (SHS) at the oxygen partial pressures of 0.25
MPa. Neutron diffraction analysis shows that final product is Ni0.38Zn0.62Fe2O4 (χ2=1.68). The
combustion temperature and propagating rate were about 1180 K and 4.2 mm/sec, respectively. The
ferrite particle size was less than about 350 nm. The coercive force, maximum magnetization,
residual magnetization, susceptibility and curie temperature of Ni0.38Zn0.62Fe2O4 powders prepared
by SHS are 2878 A/m, 6.805 Wb/m2Kg, 1.27 Wb/m2Kg , 0.042 m3/kg and 42.20 °C, respectively.
Durability and Performance of Indigenous Amorphous Silica in Advanced Cementitious Systems
Authors: Langdon A.G. , Moran G.H. , South W.
Published: March 2009

Microsilica 600 (MS60) is a highly reactive pozzolan processed from a natural white
geosilica deposit found in New Zealand’s Rotorua district. Like silica fume it is a very fine
amorphous silica and falls into the microsilica family of products. As part of a feasibility study of
using MS600 in the manufacturing process of Golden Bay Cement, this work establishes the
improved performance characteristics that can be achieved with MS600
When added with Portland cement, MS600 facilitates high performance concrete by achieving:
increased compressive strength, improved sulphate resistance, reduced alkali silica reactity, very
low chloride diffusion, reduced water permeability, improved abrasion resistance. improved
resistance to chemical attack, improved stability in geothermal environments, superior plastic
properties (moderate concrete bleed, lower heat generated, high quality finish) and low drying
shrinkage characteristics.
It has been shown that MS600 will satisfy performance requirements in applications requiring an
advanced concrete material having long serviceability in harsh environments or where structural
performance beyond current limitations are pre-requisites.
Metallurgical Nature at the Interface between Tool Shoulder and Workpiece during Friction Stir Welding
Authors: Chen Zhan W. , Pasang Timotius , Yin Q. , Peris R.
Published: March 2009

Knowledge on the contact condition at the tool/workpiece interface is essential for
understanding many aspects of FSW. In the present study, FSW experiments were conducted using
aluminium alloys followed by metallographic examination focusing on the tool shoulder-workpiece
interface region. It was observed that an interfacial intermetallic layer and hence metallurgical
sticking/soldering readily formed. Temperature measurements have suggested the presence of
interface liquid, hence suggesting a mechanical sliding contact condition dominant. This has been
supported by the observation on material flow within the shear layer.
Biomechanical and Biocorrosion Properties of Nanostructured Titanium
Authors: Zhang X.N.
Published: March 2009

The nanostructured titanium was fabricated via the surface mechanical attrition treatment
(SMAT) process and the effect of nano-crystalline structure on the biomechanical and biocorrosion
properties were studied. It was found that the Young’s modulus of nanostructured Ti decreased
significantly and thus the biomechanical property was improved. The electrochemical results
revealed that the corrosion resistance of Ti became worse after SMAT process, which is contributed
to the higher activation of the nanostructured surface.
Control of Degradation of Biocompatible Magnesium in a Pseudo-Physiological Environment by a Ceramic Like Anodized Coating
Authors: Song Guang Ling
Published: March 2009

Magnesium alloys are potential biodegradable implant materials. However, magnesium alloys normally corrode rapidly in the in-vivo fluid, resulting in subcutaneous gas bubbles and alkalisation of the in-vivo solution. The paper presents a new approach to control the degradation rate of magnesium in a simulated body fluid (SBF) through employing a recently developed anodising technique. It was found that the ceramic like anodised coating formed on the surface of magnesium can effectively slow down the biodegradation process and hence result in slow hydrogen evolution and solution alkalisation processes. The results imply that an anodised magnesium alloy may be successfully used as a biodegradable implant material.
Sonoelectroplating of Sn - Bi Solder Film from EDTA Bath
Authors: Chiba Atsushi , Kojima T. , Wu Wen Chang
Published: March 2009

This study concerns the development of Pb free solder plating due to environmental concerns. The composition of the bath was 0.1 mol/dm3 SnY and 0.1 mol/dm3 BiY- in 2 mol/dm3 CH3COOH - 2 mol/dm3 CH3COONa buffer solution (pH 4.0). The bath used 100 cm3 of solution. Plating was carried out at a current density of 50 mA/cm2 using ultrasonic agitation (sonication) at 28 kHz (100 W). Various percentages of a Sn - Bi alloy could be plated. A 41wt.%Sn - 59 wt.%Bi alloy with a melting point of 415 K was obtained from a [BiY-]/[BiY-+SnY] = 0.3 bath. The surface morphologies of the plated films showed a striking difference in accordance with a change of composition.
Investigation of Intersubband Transition in GaAs/AlGaAs Quantum Well Infrared Photodetectors
Authors: Li D.S. , Fan W.J. , Dang Y.X. , Ma B.S. , Zhang D.H. , Yoon S.F.
Published: March 2009

We report the design, characterization and fabrication of GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) to achieve intersubband transitions at expected long wavelengths. With eight-band k·p model, we calculated the E2-E1 transition energies of GaAs/Al0.25Ga0.75As QWs with the different well widths. According to the calculation, we designed a QWIP with the estimated detection wavelength around 9 μm. The actual device structure parameters, such as well width and Al composition, were confirmed by the XRD measurements. The absorption peak at 9.46 μm and the peak responsivity at 8.7 μm are obtained, which are very close to the simulation results.
Optical and Surface Morphological Study of GaN Nanocolumn Grown on Gallium Coated Si by Molecular Beam Epitaxy
Authors: Santhakumar Kannappan , Kang D.H. , Song Jae Chul , Kim Dong Wook , Kim J.S. , Kim M.D. , Lee Cheul Ro
Published: March 2009

Vertically aligned GaN nanocolumn arrays were grown by molecular beam epitaxy on
Gallium coated silicon substrate. The dense packing of the NCs gives them the appearance of a
continuous film in surface view, but cross-sectional analysis shows them to be isolated
nanostructures. The GaN nanocolumns have uniform diameters of 85 nm, lengths up to 720 nm and
possess a pyramid like tip. Photoluminescence measurements of NCs show excitonic emission with
a dominant, narrow peak centered at 363 nm and FWHM of 68 meV. From the Raman spectrum,
peaks at 566.9 and 730 cm-1 are assigned to the E2 and A1(LO) GaN phonons modes which clearly
indicates that the grown nanocolumns are highly crystalline. The grown nanocolumns are highly
oriented and perpendicular to the growth surface.
Sol-Gel Fabrication of Low Temperature Organic-Inorganic Hybrid Film Patterns for Photonic Applications
Authors: Que Wen Xiu , Ren X.M. , Zhang W. , Jiang W.J. , Gao Y. , Hu X.
Published: March 2009

Titania/organically modified silane hybrid thin films for photonic applications were
prepared by combining a low temperature sol-gel technique and a spin-coating process from an
organic-inorganic hybrid system. Effects of the titanium content and heat treatment temperature on
the structural and optical properties of the hybrid thin films were characterized by atomic force
microscopy and UV-visible spectroscopy. It is found that the optical and microstructural properties
of the hybrid thin films depend on the heat-treatment temperature and titanium molar contents. The
thickness and the refractive index of the hybrid thin films were also measured and found to be
related to the heat treatment temperature and titanium molar content. These results indicate that a
dense and high transparent hybrid thin film can be obtained at a low heat treatment temperature.
Potential photonic device structural patterns can easily fabricated from the as-prepared hybrid thin
films by using etching process.
Degradation of Photoluminescence in CdTe Nanoparticles Due to Cl2 Contamination
Authors: Gardner Hannah C. , Patel Birju , Bertoni Cristina , Gallardo Diego E. , Dunn Steve
Published: March 2009

Nanostructured CdTe is proving a popular material for a variety of modern applications.
Here, we report photoluminescent deterioration of CdTe due to Cl2 contamination. Cl2 gas was
bubbled through a 2ml suspension of thioglycolic acid capped CdTe nanoparticles whilst
photoluminescence was monitored. With the addition of only 0.02ml of Cl2 a loss of luminescence
intensity was observed. Addition of 0.4ml of Cl2 resulted in a 70% loss of luminescence intensity, a
21nm shift in wavelength, and a large narrowing of the full-width-at-half-maximum. Cl2 attacks the
Cd-S bond in the thiol capping layer of the nanoparticle, disrupting the passivation of the
nanocrystal, and allowing the formation of non-radiative trap states. Smaller nanocrystals with a
larger surface area to volume ratio are more heavily affected as is shown in the selective reduction
of intensity from the smaller particles resulting in a narrower full-width-at-half-maximum and an
apparent photoluminescence shift. A decrease in overall intensity is seen due to the lower number
of emitting particles.
The Formation of InP Ring-Shape Nanostructures on In0.49Ga0.51P Grown by Droplet Epitaxy
Authors: Jewasuwan W. , Panyakeow S. , Ratanathammaphan S.
Published: March 2009

We report on the fabrication of self-assembled InP ring-shape nanostructures on In0.49Ga0.51P by droplet molecular-beam epitaxy. The dependency of InP ring-shape nanostructural properties on substrate temperature and indium deposition rate is investigated by ex situ atomic force microscope (AFM). The nano-craters are formed when indium deposition at 120°C while the ring shape quantum-dot molecules are formed when indium deposition at 150°C or higher. The size, density and pattern of InP ring-shape nanostructures strongly depend on substrate temperature and indium deposition rate during indium deposition.