bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Ion-Sieve Type (H)[M0.5Mn1.5]O4 (M=Mg, Zn) and their Lithium Adsorption Properties in Seawater
Authors: Chung Kang Sup , Kim Mi Ae , Lee Hwan , Suh Yong Jae , Kil Dae Sup , Dave B.C. , Lee Jae Chun
Published: March 2009

Ion-sieve type manganese oxide spinels for the selective adsorption of lithium(Li) from
seawater were prepared and their properties were examined. LiM0.5Mn1.5O4 (M=Mg, Zn) precursors,
in which part of manganese(Mn) was substituted with magnesium(Mg) or zinc(Zn), were synthesized
through the solid-state reaction. The adsorbents, HM0.5Mn1.5O4 (M=Mg, Zn) were derived from
LiM0.5Mn1.5O4 (M=Mg, Zn) by acid treatment. The optimum acid treatment was obtained at
hydrochloric acid concentration of 0.5M and 0.3M for LiMg0.5Mn1.5O4 and LiZn0.5Mn1.5O4
precursors, respectively. Both cases required thrice-conducted acid treatments for the best results.
The adsorption of Li by HMg0.5Mn1.5O4 and HZn0.5Mn1.5O4 adsorbents followed the Freundlich
equation and the maximum adsorption of Li in artificial seawater was 30.3 mg/g and 33.1 mg/g,
respectively. The adsorption efficiency of Li by HMg0.5Mn1.5O4 and HZn0.5Mn1.5O4 adsorbents in
artificial seawater, in which Li concentration was adjusted to 0.2 mg/L, was as high as 88% and 89%.
Synthesis and Characterization of Ti3(Al1-n Gen)C2 by a Reactive Hot Pressing of TiCx, Al, and Ge Powder Mixture
Authors: Han Jae Ho , Nam Kyung Don , Park Sang Whan , Kim Young Do
Published: March 2009

Bulk Ti3(Al1-nGen)C2 (n=0, 0.3, 0.5, 0.7, 1.0)were synthesized by a reactive hot pressing of
TiCX (x=0.6), Al and Ge powder mixture at 1400 °C for 1 h under 25 MPa. A series of
Ti3(Al1-nGen)C2 was successfully synthesised by a hot pressing through a direct liquid-solid reaction
between Al-Ge melt and TiCx, and simultaneous densification. Synthesized bulk Ti3(Al1-nGen)C2 was
maintained a typical layered structure as shown in other ternary carbide such as Ti3AlC2 and Ti3GeC2.
With increasing Al or Ge contents in Ti3(Al1-nGen)C2, both of Vickers hardness and flexural strength
of Ti3(Al1-nGen)C2 were increased compared to those of pure Ti3AlC2 and Ti3GeC2 . The maximum
flexural strength of Ti3(Al1-nGen)C2 (n=0.3) was about 600 MPa, which was about 3 times higher than
that of pure Ti3GeC2. The Vickers hardnesses of Ti3(Al1-nGen)C2 and Ti3AlC2 were slightly decreased
with increasing an indentation load.
Synthesis of Bio-Glass Ceramics in Na2O-CaO-SiO2-P2O5 System with Fluoride Additives
Authors: Kim Sung Hwan , Kim Yae Sol , Bang Hee Gon , Park Sang Yeup
Published: March 2009

In this study, we intend to synthesize the new bio-glass composition with fluoride
additions, such as CaF2 and MgF2, instead of Na2O in bio-glass ceramic composition based on 45S5
(46.1SiO2-26.9CaO-24.4Na2O-2.6P2O5, mol%). Also, we intend to increase the SiO2 content up to 50
mol% to enhance the mechanical properties. When B2O3 (4 mol%) was added as a Na2O substitution,
thermal expansion coefficient was decreased at the sintering temperature (650~950 oC). Compared to
the low flexural strength (57±3 MPa) and vickers hardness (4.6 GPa) of sintered bio-glass ceramics
without fluoride and B2O3, bio-glass ceramics substituted with 10mol% MgF2 for Na2O showed more
higher mechanical properties (flexural strength: 141±5 MPa, vickers hardness: 5.6 GPa). Thermal
expansion coefficient of bio-glass ceramics with the ion substitutions (Ca2+, Mg2+ and B3+) was
decreased from 16×10-6/oC to 9.4~10×10-6/oC (~400 oC).
Development of Carbon Nanostructures in an Intermediate Prepared from Sol-Gel Process
Authors: Han Kyu Suk , Ko Tae Gyung
Published: March 2009

We report the observation of the carbon nanostructures simply obtained from the sol-gel
process using zirconium alkoxide with subsequent heat-treatment. A Raman study showed that the
well-defined D and G active modes in multi-walled carbon nanotube similarly appeared in the sample
prepared at 350 and 400 . Those disappeared when the sample was heat-treated above 450 , at
which its phase fully transformed to zirconia. We observed through HRTEM that either sphere or
tube-like carbon nanostructure appeared dispersedly or in a cluster among the oxide aggregates at 350
and 400 . Our study demonstrated that both of the two carbon nanostructures occurred in an
intermediate related to carbonization, which may exist during the heat-treatment even in air
Characteristics of La0.8Sr0.05Ca0.15CrO3 Interconnect Material for SOFC Synthesized by a Modified Pechini Method, USP, and GNP
Authors: Lim Tak Hyoung , Lee Gil Yong , Peck Dong Hyun , Song Rak Hyun , Shin Dong Ryul
Published: March 2009

The characteristics of La0.8Sr0.05Ca0.15CrO3 interconnect material synthesized by modified
pechini method, USP, and GNP was investigated. The powder synthesized by Pechini method
exhibited somewhat aggregated shape. The precursor synthesized by USP had spherical shape and
their particle size decreased somewhat after calcining procedure at 1000oC. In the case of GNP, the
precursor formed agglomerated particles. The average particle size of powders synthesized by Pechini
method, USP, and GNP were 0.4+m, 0.6+m, and below 10nm, respectively. The La0.8Sr0.05Ca0.15CrO3
powder had a single perovskite phase and orthorhombic structure. After sintering at 1400oC and
1500oC, the relative density of samples synthesized by pechini method was approximately 95% and
that of samples synthesized by USP was slightly small. However, that of the samples synthesized by
GNP was approximately 92%.
Sealing Properties of Ceramic Fiber Composites for SOFC Application
Authors: Lee Jae Chun , Kwon Hyuk Chon , Kwon Young Pil , Lee Ju Hyeon , Park Sung
Published: March 2009

For the sealing of solid oxide fuel cells (SOFCs), mid-term (~1,000 h) sealing performance
was examined using composite seals prepared with mixtures of a glass and alumino-silicate ceramic
fiber. Leak rate could be reduced to < ~0.04 sccm/cm when using a composite seal with 60 vol%
glass. Viscosity of the glass at the seal operating temperature of 650 was 2.0×108 dPa·s (log η =
8.3) as estimated by beam-bending method, and found to be suitable for sealing operation.
Electroless Plated Pd/GaAs Schottky Diode and its Application to Hydrogen Detection
Authors: Chou Yen I , Chen Huey Ing , Hsiung Chien Kang
Published: March 2009

In this study, the dependence of Pd/GaAs Schottky diode on the electroless plating (EP)
variable is systematically studied. Both alkaline and acidic formulas for electroless Pd depositions are
employed for investigations. The correlation between Pd gain size and the manipulation of plating
bath composition is constructed. Experimental results show that the performances of Pd/GaAs
Schottky diode, electric rectification and hydrogen detection, are largely governed by the Pd grain size.
Furthermore, without the interference of sodium ion, the acidic-plated Pd/GaAs diode with
intermediate oxide layer exhibits the excellent hydrogen sensing performances from 15 ppm to 1.0 %
H2/air.
The Effect of Initial Hydration Temperature on the Characteristics of Calcium Hydroxide and Aragonite Precipitated Calcium Carbonate
Authors: Ahn Ji Whan , Kim Jung Ah , You Kwang Suk , Kim Hwan , Cho Hee Chan , Lee Im Chan
Published: March 2009

Precipitated Calcium Carbonate (PCC) is obtained through three processes; that of
calcination, hydration, and carbonation. Thus, changes in each process condition determine the
particle size or morphology of the mediums (calcium oxide and calcium hydroxide) as well as the
product (PCC). To date, studies concerning precipitated calcium carbonate have mainly focused on
the carbonation process, aimed at the manufacturing of PCC. Thus far, few studies on calcination or
hydration have been conducted.
Calcium hydroxide is regarded as the most important factor during the carbonation process. It is
obtained through a hydration process. Therefore, in order to create the valuable PCC studies that
center on the hydration process should be carried out. The present study seeks to investigate the effect
of the hydration condition, particularly the temperature, on the synthesis characteristics of calcium
hydroxide and aragonite PCC. The results show that the particle size of calcium hydroxide changes
with variations in the initial hydration temperature. In particular, a higher initial temperature resulted
in a larger particle size of the calcium hydroxide used in the synthesis. The particle size and yield of
aragonite also increased when calcium hydroxide created at high temperatures was used. However,
the water/solid ratio or total amount at the hydration time had no effect on the manufacturing process
of aragonite.
Oxidation Behavior of Tantalum Boride Ceramics
Authors: Matsushita Junichi , Hwang Geum Chan , Shim Kwang Bo
Published: March 2009

The oxidation behavior of tantalum diboride (TaB2) powder at high temperature was
investigated in order to determine the possibility of the use of advanced high temperature structural
materials. Unfortunately, monolithic TaB2 were known to be chemical stability up to high
temperatures. To date, there have been few reports regarding the properties of TaB2 ceramics. The
samples were oxidized at room temperature to 1273 K for 5 minutes to 25 hours in air. The weight
changes were measured to estimate the oxidation resistance. The oxidation of samples oxidized for
short oxidation time of 5 minutes started at 873 K, and the weight gain increased with increasing
oxidation temperature. On the other hand, at the oxidation time of above 1 hour, a maximum weight
gain value at 973 to 1073 K was observed. However, even if the oxidation temperature was increased
an additional weight change slightly occurred. The weight gain of the sample oxidized at 1273 K for 5
minutes to 25 hours was about 40 to 20 % of the theoretical oxidation mass change. According to the
powder X-ray diffraction date, the oxidized TaB2 sample was changed to Ta2O5 at 873 K. Finally, the
TaB2 showed a good oxidation resistance at high temperature, because the surface film of tantalum
oxide (Ta2O5) formed by oxidation acted as an oxidation resistant layer.
Simulation and Characterization for the Non-Linearity of Multilayer Ceramic Capacitors with New Equivalent Circuits under Ac-Field
Authors: Jeon Hyeon Pyo , Choi Youn Kyu , Kim Sang Woo , Choi Duck Kyun
Published: March 2009

This paper describes examines the non-linearity of multilayer ceramic capacitors
(MLCC) with new equivalent circuits. The electric charge quantity (Q) was measured as a function
of applied voltage (V) under 16 V ac-field to validate the ferroelectricity of MLCC with capacitance
of 1 μF. The Q-V curves predicted under ac-field using B2 spice software showed the non-linearity
of ferroelectricity in the high ac-field. The Q-V curve predictions were in agreement with the
experimental data for the MLCC.
First Principle Calculations of the Magnetic Structures of 3d Transition Metals Doped GaN
Authors: Lee Seung Cheol , Lee Kwang Real , Lee Kyu Hwan
Published: March 2009

First principle calculations were performed on the electronic and magnetic structures of
the transition metals doped GaN. Seven elements in 3d transition metals from V to Cu were used as a
dopant. Magnetic phase was stable compared to non-magnetic phase for all transition metals doped
GaN. Total magnetic moments followed Hund’s rule to maximize the magnetic moment. Transition
element projected magnetic moments showed that most of magnetic moments were concentrated on
transition metals in the cases of V, Cr, and Mn doped GaN, which could not be used for DMS. Since
Fe and Ni doped GaNs are intrinsic insulators, Fe and Ni doped GaNs could not be used for DMS
materials unless additional dopants are introduced. The most probable candidates for DMS
applications were predicted to be Co or Cu doped GaNs, respectively.
Low-Temperature Synthesis of Ordered L10-FePtCu Nanoparticles with High Coercivity
Authors: Ryu Han Wool , Sato Kazuhisa , Hirotsu Yoshihiko
Published: March 2009

Oriented and densely dispersed L10-FePtCu nanoparticles have been directly synthesized
by co-evaporation of Fe, Pt and Cu using rf-magnetron sputtering onto NaCl substrate kept at
563-613K without any post-deposition annealing. Under as low a substrate temperature as 563K,
superlattice reflections of the L10 phase appeared in selected area electron diffraction pattern, while
the intensity was quite weak. As the substrate temperature increased from 563K to 613K, <100>
oriented growth as well as the atomic ordering were promoted, resulted in a large increase of
coercivity.
Glycothermal Synthesis and Magnetic Properties of YIG/YAG Nanoparticles
Authors: Noda Kunihiro , Asakura Ryo , Isobe Tetsuhiko , Morita Masahito , Kurokawa Kiyoshi , Inubushi Toshiro , Takagi Tomohiro , Ohkubo Michio
Published: March 2009

Yttrium aluminum garnet (YAG) nanoparticles of 14.5±3.2 nm in diameter are synthesized
from yttrium acetate and aluminum isopropoxide in 1,4-butanediol by autoclave treatment at 300oC
for 2h. Yttrium iron garnet (YIG) / YAG composite nanoparticles of 21.1±4.9 nm in diameter are
synthesized from yttrium acetate and iron(III) acetylacetonate in 1,4-butanediol by autoclave
treatment at 300oC for 2h using YAG nanoparticles as the seed. In contrast, YIG is not formed by the
same procedure in the absence of the YAG seed. The saturation magnetizations of nanoparticles with
different YIG/YAG ratios range from 11.9 to 17.8 emu/g. YIG/YAG nanoparticles dispersed in the
agarose gel are observed by magnetic resonance imaging (MRI). The degree of the negative MRI
contrast depends on the concentration of YIG/YAG nanoparticles.
Magnetic Patterning of the Ni/Cu Thin Film by 40 keV O Ion Irradiation
Authors: Lee Jong Han , Shin Sang Won , Kwon Young Suk , Choi In Hoon , Whang Chung Nam , Kim Tae Gon , Song Jong Han
Published: March 2009

Ni(60Å)/Cu film possessing perpendicular magnetic anisotropy (PMA) changes its easy
direction into the plane by ion irradiation, due to the relaxation of the strain. By fixing our eyes upon
this magnetic property, the magnetic patterning of Ni(60Å)/Cu film using 40 keV O ion irradiation
was performed through the photo-resist (PR) mask having 10㎛ x 10 ㎛pattern sizes to pattern the
magnetic film. After the PR mask removal of an irradiated film, the magnetic properties were
investigated by the magneto-optic Kerr effect and the formation of magnetic pattern was observed by
the magnetic force microscopy. The PMA magnetic patterning of epitaxial Ni/Cu film was
successfully performed in scale of ㎛ by using ion irradiation, compatible with device process.
Potential of Cr2AlC Ternary Carbide as Material for Bipolar Plate in PEMFC
Authors: Jayaraj Jayamani , Han Jae Ho , Park Sang Whan , Kim Ki Bae , Fleury Eric
Published: March 2009

In this paper, we present results of an investigation on the physical, mechanical, chemical
properties and processing ability of the Cr2AlC ternary carbide bulk material synthesized by hot
pressing technique. The combination of excellent properties indicated that Cr2AlC ternary carbide alloy
could be potential candidate materials as bipolar plates in polymer membrane fuel cell (PEMFC).
Growth of Cu(In1-xAlx)Se2 Thin Films by Atmospheric Pressure Selenization of Sputtered Precursors
Authors: Munir Badrul , Wibowo Rachmat Adhi , Lee Eun Soo , Kim Kyoo Ho
Published: March 2009

Cu(In1-xAlx)Se2 films were prepared using a two-stage process of sputtering and
selenization. Stacked elemental layer precursors of Cu, In and Al were deposited onto corning
glass substrates by RF magnetron sputtering. Precursors with different Cu/(In+Al) and In/Al
ratio were selenized using elemental Se-vapor at atmospheric pressure in a commercial tube
furnace under constant argon gas flow. Films with good adhesion to the substrate were grown
successfully. All of the films show strong (112) and (220)/(204) CIS peaks. Addition of Al, at
expense of In, shifts the peaks towards higher 2θ. This paper explores the possibility to use
sputtering deposition and selenization process to grow Cu(InAl)Se2 thin films for solar cells
applications.
Electrochemical Performance of Activated Carbon Electrode Added with LiCoO2 for Hybrid Capacitor
Authors: Kim Ick Jun , Jeon Min Je , Yang Sun Hye , Moon Seong In , Kim Hyun Soo
Published: March 2009

In this study, mixed active material electrodes, composed of an activated carbon (MSP20)
and LiCoO2, were prepared as cathodes for a high-capacitive hybrid capacitor. The electrochemical
properties of (MSP20+LiCoO2)/Li cells were examined in terms of the weight composition and the
particle size of LiCoO2 powder in the electrodes. As adding more LiCoO2 powders in the electrode,
the volumetric capacity (mAh/ml) of the electrode became higher. In order to examine the size effect
on the electrochemical performance, the LiCoO2 powders were modified by ball milling. The
(MSP20+LiCoO2)/Li cells using 10 and 20 wt.% of 30h-milled LiCoO2 powder exhibited the lower
internal resistivities and the better capacity retentions after 100 charge-discharge cycles than those
using 10 or 20 wt.% of raw LiCoO2 powders.
Characterization of Cu(In,Ga)3Se5 Thin Film for Top Cell in CIGS Tandem Solar Cells
Authors: Kim Ki Hwan , Ahn Byung Tae , Kwon Se Han , Yun Jae Ho , Yoon Kyung Hoon
Published: March 2009

Cu(In,Ga)3Se5 films were deposited on soda-lime glass substrate by three-stage
co-evaporation process. In the film, the band gap increased as the Cu content decreased and also as the
Ga content increased. The grain size became smaller as the Ga content increased. In the
Cu1.29(In1-xGax)3Se5 system, the maximum hole concentration was 1x1015 /cm3 when the Ga content
was 0.5 and its band gap was 1.45 eV. Comparing the conventional CIGS solar cell with
Cu0.8(In0.7Ga0.3)Se2 film, the series resistance is too large, indicating that further p-type doping in the
Cu(In,Ga)3Se5 film is necessary to improve cell efficiency for the top cell application in CIGS tandem
solar cells.
Formation of CuIn1-xAlxSe2 Thin Films by Selenization of Metallic Precursors in Se Vapor
Authors: Yun Jae Ho , Chalapathy R.B.V. , Lee Jeong Chul , Song Jin Soo , Yoon Kyung Hoon
Published: March 2009

CuIn1-xAxlSe2(CIAS) films were obtained by selenization process of metallic precursors.
The metallic precursors were deposited sequentially by using sputtering system. As the ratio of
Al/(Al+In) in the precursors increased, the chalcopyrite (112) peak shifted to high value and the
band-gap of CIAS layer increased to 1.38 eV. However, the bi-layer morphology with well
crystallized large grain on the surface and small grain thin bottom layer was observed. Although the
sequences of precursors were changed in order to get uniform layer, no distinguishable difference
was not observed.
Electrochemical Comparison of Chemically or Physically Modified Natural Graphite Anode for Lithium-Ion Batteries
Authors: Shim Joong Pyo , Lee Hong Ki , Song Byung Ho
Published: March 2009

Natural graphite anodes were treated by different methods to improve their cyclability.
We tried following methods; heat-treatment at 550oC for graphite powder, addition of carbon black
for electrode and VC (vinylene carbonate) in electrolyte. All methods decreased capacity fade rate
during constant cycling. The addition of carbon black decreased capacity fade significantly but
increased irreversible capacity much at first cycle. Heat-treatment and VC were also effective for
cycling and irreversible capacity loss.
Direct Synthesis of Isolated L10-FePtCu Nanoparticles by RF-Magnetron Sputtering
Authors: Ryu Han Wool , Sato Kazuhisa , Hirotsu Yoshihiko
Published: March 2009

Isolated and oriented hard magnetic FePtCu ternary alloy nanoparticles with the L10-type
ordered structure have been directly fabricated by rf-magnetron sputtering onto NaCl substrate kept
at 613K without any post-deposition annealing. Structure and morphology of those particles were
studied by TEM. When the sputtering duration decreases, the particle size decreases and the particle
areal number density increases. These nanoparticles have <100> orientation on the NaCl substrate.
Alloy composition distribution from particle to particle examined by nano-beam elemental x-ray
analysis was found to be quite small, which can be attributed to the homogeneous structure formed
by co-deposition of Fe, Pt and Cu by sputtering. Thermal fluctuation of the magnetization becomes
prominent in the specimen with the particle size smaller than about 10nm in diameter.
On the Liquidus Surface and Reaction Scheme of the Ternary System Cu-Si-Ti
Authors: Berbecaru Adina , Naka Masaaki , Schuster Julius C.
Published: March 2009

The ternary system Cu-Si-Ti was investigated using XRD, SEM-EDX, and DTA.
The existence of two ternary phases τ1-CuSiTi and τ2-TiSi2-xCux as well as their crystal
structures are confirmed. The isothermal section at 800°C is corroborated. From DTA data of
equilibrated alloys a reaction scheme linking the isotherm at 700°C with the liquidus surface
is derived. Using data on primary crystallisation of as cast alloys a projection of the liquidus
surface is proposed.
Characterization and Dissolution Behavior in a Physiological Solution of Heat-Treated CaTiO3 Thin Films with Different Thicknesses
Authors: Ohtsu Naofumi , Saito Kesami , Asami Katsuhiko , Hanawa Takao , Kimura Hisamichi
Published: March 2009

Characterization of heat-treated CaTiO3 thin films of 10, 20, 30 and 50 nm in thickness and their change after immersion in a simulated body fluid were investigated by grazing incident angle X-ray diffractometry and Auger electron spectroscopy (AES). The CaTiO3 films were prepared on titanium substrate by sputter-deposition of CaTiO3 target followed by heating in an electric furnace at 873 K in air for 7.2 ks. The CaTiO3 films were immersed in 0.8% NaCl solution for 14 d. All the films before heat treatment were non-crystallized films and after heat treatment, only the 50-nm film was crystallized to perovskite-type CaTiO3. In AES in-depth profiles after heating, Ca diffusion was not observed in the 50-nm film, whereas Ca diffusion toward the Ti substrate was observed in the 10-, 20- and 30-nm films. After immersion for 14 d, the vicinity of surface of the 10, 20 and 30 nm thick CaTiO3 films were dissolved into the NaCl solution, while the 50-nm thick CaTiO3 film was scarcely dissolved. Since dissolution from biomaterials in a human body has possibility to harm, the CaTiO3 film should be deposited more than 50 nm in thickness and heat-treated at 873 K.
Development of Large Area Plasma Reactor Using Multiple Low-Inductance Antenna Modules for Flat Panel Display Processing
Authors: Setsuhara Yuichi , Takenaka Kosuke , Ebe Akinori , Nishisaka Kazuaki
Published: March 2009

This article reports characteristics of plasmas sustained with LIA modules and profile control capabilities. Experiments with a meter-scale reactor demonstrated uniform plasma production to attain densities as high as 5x1011 cm-3 at an argon pressure of 1.3 Pa and an RF power of 4 kW. Design issues for large-area plasma sources with a scale-size of 3 m were also presented to exhibit the feasibility of novel large-area plasma sources to meet the requirements of the next-generation meters-scale processing.
Pulsed Electric Current Bonding of Tungsten to Copper with Intermediate Layer
Authors: Nishimoto Akio , Akamatsu Katsuya
Published: March 2009

Pulsed electric current sintering (PECS) was applied to the bonding of W (tungsten) to
Cu (copper) using Nb or Ni powder as an intermediate layer. The influence of the intermediate layer
on the bond strength of the joint was investigated by observation of the microstructure. The bonding
process was carried out at carbon-die temperatures of 1073 and 1173 K for 1.8 ks at a bonding
pressure of 130 MPa. The bond strength of the joint with an intermediate layer of Ni powder was
250 MPa. This joint fractured in the Cu base during the tensile test. SEM observations of the joint
with an intermediate layer of Ni revealed that a diffusion layer formed at the joint interface.
Laser Cladding of Fe-Cu Based Alloys on Aluminum
Authors: Uenishi Keisuke , Ogata Yasuhito , Iwatani Shingo , Adachi Akira , Sato Takehiko , Kobayashi Kojiro F.
Published: March 2009

For the improvement of a surface wear resistance of aluminum alloys, iron-based alloys
were clad on the surface of an aluminum alloy by laser. By investigating the effect of CO2 and
diode laser irradiation conditions on the formability of Fe-Cr-C clad layers, it was confirmed that
the application of diode laser made it possible to obtain stable beads in low heat input compared
with CO2 laser, which has been conventionally used for laser cladding. Besides, by optimizing the
laser parameters, the dilution ratio of clad layers by Al substrate was minimized less than 10%. At
the clad interface, the reaction layer consisting of Fe2Al5 and FeAl3 formed which caused cracks at
the clad interface. Even by controlling laser conditions, this brittle layer formation could not
suppressed. In this research, by using the immiscible Fe-Cu-Cr alloys as clad materials, Fe based
clad layers were formed on Al substrate without any cracks at clad interface. By the effect of
Marangoni motion of decomposed duplex liquid phases, Cu segregated between Al substrate and Fe
based clad layers and suppressed the reaction between them.
Host Size Effects on Optical Properties of Y2O3:Eu3+ and Gd2O3:Eu3+ Nanoparticles Synthesized by Laser Pyrolysis
Authors: Ledoux G. , Leconte Yann , Amans D. , Dujardin C. , Combemale Lionel , Herlin-Boime Nathalie , Reynaud Cecile
Published: March 2009

Rare earth doped materials have many familiar applications (TV screens, solid lasers,
scintillators…) thanks to their efficient and robust luminescence properties. In recent years,
growing interest has been focused on the changes in their optical properties with the size of the host
particles. In this work, nanomaterials were produced for the first time by using laser pyrolysis. Y,
Gd, and Eu nitrates were dissolved in water and used as precursors. Cubic phases of Y2O3:Eu3+ and
Gd2O3:Eu3+ were obtained with sizes ranging from 3 to 40 nm. The spectroscopic properties
revealed a new and nanostructure-specific broad band in the excitation spectrum. The emission
spectrum was found to be characteristic of nanostructured sesquioxides only when excited in this
new band, which was finally assumed to be a new charge transfer band for the smallest
nanoparticles in the sample.
Concentration Dependent Fluorescence Lifetime in Nanocrystalline Y2O3:Eu Phosphors
Authors: Kaps Harald , Arefin Mohammad Lutful , Herr Ulrich , Paul Heiko
Published: March 2009

Nanocrystalline (Y1-xEux)2O3 powder was synthesized via a chemical vapour reaction. Xray
diffraction revealed the structure of cubic yttria with crystallite sizes of about 5 nm. The Eudopand
concentrations x for the samples in the range from 0.003 up to 0.165 were determined by
EDX-spectra. The luminescence of the nanopowders was investigated by continuous and timeresolved
UV-fluorescence spectroscopy and compared to a microcrystalline Y2O3:Eu phosphor as a
reference. The emission spectra show an increasing intensity for higher doping concentrations.
However, compared to the microcrystalline material the yield was significantly lower. The lifetime
of the 5D0 – 7FJ transition in the nanocrystalline Y2O3:Eu was found to be significantly longer than
for the microcrystalline reference sample. For increasing Eu-content the lifetime in the
nanocrystalline samples decreased continuously from 3.71 ms to a value of 1.20 ms for the highest
doping concentration. The concentration dependent lifetime behaviour was interpreted by energy
transfer between Eu ions and from Eu ions to impurities as a competing process to the radiative 5D0
– 7F2 transition.
Catalytic Decomposition of Ethylene on Nanocrystalline Cobalt
Authors: Narkiewicz Urszula , Podsiadły Marcin , Pełech Iwona , Arabczyk Waleran , Woźniak M.J. , Kurzydlowski Krzysztof Jan
Published: March 2009

Nanocrystalline cobalt was carburised with ethylene in the range 340– 500°C to obtain Co(C) nanocapsules. The carbon deposit was reduced by a flow of hydrogen in the range 500– 560°C. The reduction kinetics were studied using thermogravimetry, described by the equation: α = Α[1-exp(-kt)n]. The apparent activation energy of the reduction process of the carbon deposit was determined. After carburisation and reduction the samples were examined by XRD and HRTEM.
Comparative Analysis of ZnS:Mn2+ Nanophosphors Prepared by Hydrothermal and Low Temperature Precipitation Methods
Authors: Park Je Hong , Lee Sung Hoon , Kim Jong Su , Kim Tae Wan , Park Hong Lee
Published: March 2009

Manganese-doped ZnS nanophosphors were synthesized by two different methods: hydrothermal and low-temperature precipitation methods. The nanophosphors prepared by the hydrothermal precipitation and low-temperature methods had the size of 20 nm and 4 nm, respectively, and both were the cubic phase. The emission intensity of the nanophosphor prepared by the hydrothermal method was optimized at 10 mole % of Mn2+ concentration whereas that by low-temperature precipitation method was optimized at 3 mole % of Mn2+. The precipitationprepared nanophosphor, of size 4nm, showed a blueshift in the excitation spectrum and a redshift in the emission spectrum compared to the hydrothermal-prepared 20 nm nanophosphor. These phenomena can be explained in terms of the quantum confinement effect. The decay times especially were lengthened with decreasing particle size. This can be explained in terms of the variation in the transition probability induced from the quantum confinement effect.
Interface Shape Change and Shift Kinetics on the Nanoscale
Authors: Erdélyi Z. , Beke Dezső L. , Langer G.A. , Csik A.
Published: March 2009

In nanostructured materials, where the density of grain- and interphase-boundaries is high,
the diffusion and kinetics of surface segregation, i.e. the effective material flow is always influenced by
the contributions of these boundaries [1]. Diffusion on the nano/atomic scales in multilayers, thin films
has many challenging features even if the role of structural defects can be neglected and ‘only’ the
effects related to the nano/atomic scale arise. Different examples for diffusional nanoscale effects
discovered recently by the authors will be given in this paper. We show that the continuum descriptions
of diffusion cannot be applied automatically on such short distances, the classical continuum
approximations (Fick's laws) cannot describe correctly the atomic movements. [2-4] They predict faster
kinetics than the atomistic models and the interface shift is always proportional to the square-root of
time (x ∝ t1/2 ⇒ x2 ∝ t: parabolic or Fickian kinetics). As we will show, however, the kinetics can be
even linear (x ∝ t) on the nano/atomic scale. [3, 4] Furthermore, the continuum descriptions foretell
infinitely fast kinetics as the time goes to zero (v=dx/dt∝1/t1/2), which is a long standing paradox of
diffusion theory. We will show a possible resolution of this paradox. [5] Moreover, we will show that an
initially diffused interface can sharpen even in completely miscible systems. [6, 7]
Materials Hardness Estimation by Simulation of the Indentation Process
Authors: Spychalski M. , Wejrzanowski Tomasz , Kurzydlowski Krzysztof Jan
Published: March 2009

In the present study Finite Element Method (FEM) has been applied for modelling of
indentation process in polycrystalline metals. Two different models of the material, with linear and
non-linear hardening, have been assumed in calculations. The indentation process has been
quantitatively described by load-depth curves. The hardness values were obtained from the
unloading part of such curves, which are responsible for plastic deformation of the material during
indentation process. In addition, the geometry changes of the indent after deformation have been
analyzed. The results show that simulation techniques, used in the present study, are useful in
estimation of materials hardness. It has been also found that specific combination of materials
properties such as hardening exponent, hardening coefficient, tangent modulus and yield stress may
result in sink-in or pile-up phenomenon. These processes may influence the indent geometry and
hardness measurements consequently.
Interface Dynamics of Melt Instabilities on Semiconductor Surface
Authors: Datsko Bogdan , Meleshko Vitaliy , Świątek Zbigniew , Mohylyak Ivan , Lityńska-Dobrzyńska Lidia , Zięba Paweł
Published: March 2009

At uniform excitation of semiconductors by laser radiation with pre-threshold
power, locally melted regions are formed on irradiated surfaces. This is induced by thermo
diffusive instability of a distribution of uniformly generated electron-hole plasma. The shapes
of locally melted regions give rise to a great variety of interesting surface patterns. A
mathematical model of the surface dynamics, when the instability of the melt front arises
along a chosen wave vector, is proposed. The results of computer simulation of interface
dynamics of solitary melted region are compared with experimental data.
Monte Carlo Simulation of Texture and Microstructure Transformation during Annealing of Steel
Authors: Li Hua Long , Park Jong Tae , Szpunar Jerzy A.
Published: March 2009

Controlling texture and microstructure evolution during annealing processes is very
important for optimizing properties of steels. Theories used to explain annealing processes are
complicated and always case dependent. An recently developed Monte Carlo simulation based
model offers an effective tool for studying annealing process and can be used to verify the
arbitrarily defined theories that govern such processes. The computer model takes Orientation
Image Microscope (OIM) measurements as an input. The abundant information contained in OIM
measurement allows the computer model to incorporate many structural characteristics of
polycrystalline materials such as, texture, grain boundary character, grain shape and size, phase
composition, chemical composition, stored elastic energy, and the residual stress. The outputs
include various texture functions, grain boundary and grain size statistics that can be verified by
experimental results. Graphical representation allows us to perform virtual experiments to monitor
each step of the structural transformation. An example of applying this simulation to Si steel is
given.
Martensitic Transformation, Structure and Magnetic Properties of Co-Ni-Ga Ferromagnetic Shape Memory Alloys
Authors: Kostrubiec B. , Prusik Krystian , Madej Ł. , Morawiec Henryk
Published: March 2009

In the present paper the effect of heat treatment on microstructure, martensitic
transformation temperatures and magnetic properties behavior of Co-Ni-Ga pollycrystal was
discussed in detail. Microscopic observations revealed two types of two phase polycrystalline
alloys: i) martensite with γ-precipitates and ii) parent phase with γ-precipitates. Making use of Xray
and electron diffraction methods the crystal structure of martensite phase was identified as bct
structure (with co/ao about 1.2). Annealing of Co-Ni-Ga alloy at 1223K/40 min causes a separation
of martensitic and magnetic transformation and an increase of the Curie temperature by about 70K,
after this annealing any significant structural changes in the parent (martensitic) and γ phase are not
observed.
Phase Transformation in Ti-Ni-Ta Shape Memory Alloy
Authors: Lekston Zdzisław , Goryczka Tomasz
Published: March 2009

A new Ti50Ni48.7Ta1.3 shape memory alloy was designed for medical application. In order to influence the martensitic transformation temperature the alloy was solution treated and additionally aged at 400oC for various time. Phase transformation was studied applying differential scanning calorimeter (DSC) and X-ray diffraction techniques. The ageing causes that the martensitic transformation occurs in two steps: B2↔R↔B19’ during cooling and heating. During cooling the transformations: B2→R and R→B19’ are well separated whereas on heating they are overlapped. Also ageing causes a shift of temperatures of the martensitic transformation into the higher region. It is due to the precipitation process. Precipitates of the Ni4Ti3 phase were observed. Applied thermal treatment leads to shift of the transformation temperatures below temperature of a human body. This makes the Ti-Ni-Ta alloy attractive for application in medicine.
Three-Dimensional Visualization in Powder Diffraction
Authors: Izumi Fujio , Momma Koichi
Published: March 2009

A multi-purpose pattern-fitting system, RIETAN-2000, has been extensively utilized to
contribute to many structural studies. It offers a sophisticated structure-refinement technique of
whole-pattern fitting based on the maximum-entropy method (MEM) in combination with a MEM
analysis program PRIMA. We have recently completed a successor system, RIETAN-FP, to
RIETAN-2000, adding new features such as standardization of crystal-structure data, an extended
March-Dollase preferred-orientation function, and automation of imposing restraints on bond
lengths and angles. Further, we have been developing a new three-dimensional visualization system,
VESTA, using wxWidgets as a C++ application framework. VESTA excels in visualization, rendering,
and manipulation of crystal structures and electron/nuclear densities determined by X-ray/
neutron diffraction and electronic-structure calculations. VESTA also enables us to display wave
functions and electrostatic potentials calculated with part of these programs.
Mössbauer and XRD Studies on Composite Powder with Phases from Fe-Al System Obtained by Mechanically Activated SHS Mehtod
Authors: Frąckowiak J.E. , Hanc Artur , Dercz Grzegorz , Pająk Lucjan , Formanek Boleslaw
Published: March 2009

The systematic studies of non-stoichiometric phases from Fe-Al system obtained by selfpropagating
high-temperature synthesis (SHS) were the aim of the present work.
Investigations were performed using 57Fe transmission Mössbauer spectroscopy. The presence
of nonsteichiomertic FeAl, FeAl2 and Fe2Al5 phases was found. It is can be concluded that
the studied powder material is in non-equilibrium state. As the result of milling process the
contents of FeAl phase increase whereas of FeAl2 and Fe2Al5 ones decrease. The determined
crystal structure parameters and the hyperfine interaction parameters are presented and
discussed.
Structure Analysis of Nanocrystalline MgO Aerogel Prepared by Sol-Gel Method
Authors: Dercz Grzegorz , Pająk Lucjan , Prusik Krystian , Pielaszek Roman , Malinowski Janusz J. , Pudło Wojciech
Published: March 2009

Wet gel obtained by sol-gel technique was dried in supercritical CO2 to prepare hydrated form of magnesium oxide. Calcination at 723 K under vacuum yielded nanocrystalline MgO aerogel. Structure studies were performed by X-ray diffraction, scanning and transmission electron microcopies. Electron microscopy images reveal rough, unfolded and ramified structure of solid skeleton. Specific surface area SBET was equal to 238 m2/g. X-ray pattern reveals the broadened diffraction lines of periclase, the only crystalline form of magnesium oxide. The gamma crystallite size distribution was determined using FW 5 4 / 5 1 M method proposed by R. Pielaszek. The obtained values of  and σ (measure of polydispersity) of particle size parameters are equal to 6.5 nm and 1.8 nm, respectively, whereas the average crystallite size estimated by Williamson-Hall procedure was equal to 6.0 nm. The obtained at Rietveld refinement Rwp, and S fitting parameters equal to 6.62% and 1.77, respectively, seem to be satisfactory due to the nanosize of MgO crystallites and because of the presence of amorphous phase.
A Comparative Study of the Structure and Properties of Zinc Coatings Deposited with Various Methods
Authors: Vourlias G. , Pistofidis N. , Chaliampalias D. , Stergioudis F.
Published: March 2009

One of the most effective methods for the protection of ferrous substrates from corrosion
is zinc hot-dip galvanizing. Although this method has many advantages, it is characterized by a very
negative effect on the environment. In the present work Zn coatings were formed with thermal
spraying, pack cementation and fluidized bed reactor, which are friendlier to the environment. Their
microstructure was characterized with X-ray diffraction and scanning electron microscopy, while
their corrosion performance was estimated with exposure in a salt spray chamber. From this
investigation it was deduced that CVD coatings are composed by two layers referring to Γ-Fe11Zn40
and δ-FeZn10 phase of the Fe-Zn phase diagram. By contrast the thermal coatings are very porous
and composed by pure Zn. However, the corrosion performance of all coatings is similar. This
conclusion is very important because it verifies that hot-dip galvanizing could be replaced by the
other coating methods.
Microstructural Studies on the Q-Phase in Alumina Cement Clinker
Authors: Podwórny J. , Wala T. , Sawków J.
Published: March 2009

were synthesized in a two-step sintering process. Qualitative and quantitative XRD and Rietveld method were applied to control the degree of reaction after each sintering step. Two microscopic techniques for Q-phase crystal habit determination were applied: reflected light microscopy and electron scanning microscopy. Additionally, WDS x-ray microprobe for chemical composition determination of pleochroite crystals was used. A microscopic observation of the polished sections and fractures etched with 10 % HCl and 1 % Borax water solution was carried out. It was observed that Q-phase crystallised in a prism form on the non-etched samples. Lamellar microstructure of prismatic pleochroite crystals on the etched samples was revealed and layers of intergrowths (most probably gehlenite (Ca2Al2SiO7) were observed. The obtained results were discussed on the basis of literature data.
Temperature-Controlled Devitrification of Oxyfluoride Borate Glasses
Authors: Pisarska Joanna , Goryczka Tomasz , Pisarski Wojciech A.
Published: March 2009

Selected oxyfluoroborate glasses have been investigated before and after heat treatment. Transparent glass-ceramics (TGC) were obtained during controlled crystallization (devitrification). X-ray diffraction studies confirmed that material was partially crystallized. Diffraction lines due to orthorhombic PbF2 phase were identified for heat-treated samples at various temperatures and times. Results were compared to that ones obtained for as-melted glass.
Structural Changes in New Rapidly-Quenched Finemet Type and Hitperm Type Alloys
Authors: Staszewski Mariusz , Woch M. , Kolano-Burian Aleksandra , Barszcz J. , Buczek M.
Published: March 2009

Structural transformations taking place during annealing of rapidly-quenched soft magnetic
ribbons from the Finemet type and Hitperm type alloys were investigated. The X-ray quantitative
phase analysis and X-ray diffusion scattering methods were used. It was found that the structural
changes in the alloys studied, including crystallisation process and short-range ordering in the
amorphous phase, are reflected by the changes in their magnetic properties. These properties, and
particularly the magnitude of saturation induction Bs , depend on the content of cobalt and silicon in
these alloys and on short-range order in the amorphous phase.
Studies on Al2O3 - ZrO2 Coatings Structure before and after Thermal Treatment
Authors: Górski Ludwik , Pawłowski Andrzej
Published: March 2009

Phase transitions occurring in the Al2O3-ZrO2 composite as a result of plasma
spraying and subsequent coating annealing are described. X-ray diffraction and transmission
electron microscopy methods are applied to study these effects. Separate layers of amorphous,
nano- and fine-crystalline structure with the columnar crystals areas have been observed.
Thermal treatment causes formation of more ordered phases. Effect of partial stabilization of
cubic and tetragonal zirconia due to the presence of alumina has been remarked.
Growth and Structure of Zn1-xMnxCr2Se4 Single Crystals
Authors: Jendrzejewska Izabela , Waśkowska Alicja , Augustyn Elżbieta
Published: March 2009

The single crystals of ZnCr2Se4 spinel doped with manganese were prepared by the chemical
vapour transport in closed silica tubes using stoichiometric contents of ZnSe, MnSe and CrCl3 as
the transporting agent. Chemical composition of four single crystals of Zn-Mn-Cr-Se system with
different concentration of manganese was analyzed and confirmed by X-ray diffraction study. The
structure refinements, taking into account site occupancy factors, indicated that Mn ion shared
tetrahedral sites with Zn ion. Thus, the formula describing cation distribution in the system is:
Zn1-xMnxCr2Se4. For all x values equal to 0.12, 0.13, 0.18 and 0.24, the observed symmetry was
cubic, space group Fd 3m .
Degradation and their Recovery Behavior of Irradiated GaAlAs LEDs
Authors: Ohyama H. , Takakura K. , Nagano T. , Hanada M. , Kuboyama S. , Simoen Eddy , Claeys Cor
Published: March 2009

The degradation and recovery behavior of device performance on GaAlAs LEDs (Light
emitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are investigated. The reverse
current increases after irradiation, while the capacitance decreases. The device performance
degradation is proportional with fluence. For electron irradiation, fluence rate is also effective for
degradation. Low fluence rate shows more large degradation compared to high fluence rate
resulting from heat impact in bulk. DLTS measurement reveals the DX center in epitaxial substrate,
and this spectrum increases with fluence. The radiation damage of proton is larger than that of
electron irradiation, which is caused by the difference of mass and possibility of nuclear collision
for the formation of lattice defects. After irradiation, the device performance recovers by thermal
annealing.
Enhanced Oxygen Precipitation during the Czochralski Crystal Growth
Authors: Válek Lukas , Šik Jan , Lysáček David
Published: March 2009

An unusual pattern of the Oxidation Induced Stacking Faults (OISF) in the heavily
boron-doped silicon is reported. Instead of the commonly reported simple OISF ring, we observe
a banded OISF pattern. The pattern reflects the distribution of residual vacancies as it is described
by Voronkov and Falster [J. Crystal Growth 204 (1999) 462]. We show that the oxygen precipitates
in the L- and H- bands grow to an abnormally large size during the crystal growth and which serve
as the OISF nuclei during subsequent wafer oxidation. It is concluded that a combination
of the high boron, oxygen and vacancy concentration is responsible for the enhanced oxygen
precipitation during the crystal growth.
Detection of Nickel in Silicon by Recombination Lifetime Measurements
Authors: Savin Hele , Yli-Koski Marko , Haarahiltunen Antti , Talvitie H. , Sinkkonen Juha
Published: March 2009

The impact of nickel on minority carrier recombination lifetime has been studied in ptype
CZ silicon using SPV and μ-PCD techniques. The results show that small oxide precipitates
can be used to improve drastically the detection limit of nickel. This is explained by the decoration
of oxide precipitates by nickel, which results in the enhanced recombination activity. In the absence
of oxide precipitates or other related bulk microdefects nickel precipitates preferably to wafer
surfaces, which does not have such a high impact on the measured recombination lifetime, at least
on a low concentration level. Low temperature anneal at 180°C or light illumination of the wafers
after nickel in-diffusion did not reveal any further change in lifetime in any of the wafers, which
may indicate that nickel precipitates efficiently during air-cooling from high temperature.