bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of One-Dimensional Magnetic Particles Chain of Polycrystalline Nickel under Magnetic Field
Authors: Xie Sheng Li , Xu Li Na , Gu Ning
Published: March 2009

Nanoscale magnetic materials have been receiving increasing interest for their potential
applications. One-dimensional magnetic particles chain of polycrystalline nickel was prepared by a
simple template-free method under magnetic field. Based on solution reduction reaction of Ni2+,
metallic nickel was deposited and synchronously self-assembled into chains under magnetic field.
The results show that the chain of polycrystalline nickel was several micrometer in length and
several hundreds nanometer in diameter. VSM measurements indicate the magnetic properties of
chains formed can be modulated by the reaction time and the solution concentration. It is suggested
that the magnetic field be an effective and tunable way to the fabrication one-dimensional chains of
magnetic materials.
Functionalized Tetrapod-Like ZnO Nanostructrures for DNA Gene Delivery
Authors: Nie Leng , Gao Li Zeng , Yan Xi Yun , Wang Tai Hong
Published: March 2009

Amino-modified tetrapod-like ZnO nanostructures were tried as novel carriers for
mammalian cell transfections. The nanostructures consisted of four needle-shaped tetrahedrally
arranged legs connected at the center. After silica coating and amino modification, ZnO
nanostructures complexes bound plasmid DNA through electrostatic interactions in aqueous solution.
When mixed with cells, DNA-nanostructures attached easily onto cell membranes and entered the
cells for gene expressions. Due to high positive charge densities on surfaces and needle-shaped
tetrahedral structures, functionalized ZnO used as carriers for cell transfections with both high
transfection efficiency and little cytotoxicity. And a possible transfection machamism was proposed
in this report.
A Flow Sensor for Liquids Based on Single-Walled Carbon Nanotube Thin Films
Authors: Cao C.L. , Fang Liang , Liao K.J. , Wei F.J. , Li L.
Published: March 2009

An angular velocity of flow sensor for liquids based on single-walled carbon nanotube
thin films is presented. The carbon nanotubes in this study were fabricated on Si substrate by hot
filament chemical vapor deposition (CVD). The experimental results showed that the flow-induced
current on the surface of carbon nanotube thin films was closely depended upon the angular
velocity, concentration, properties and temperature of the liquids. The current increased with
increasing angular velocity, concentration and temperature of the liquids. In this study, the liquids
such as water, NaCl solution and other electrolyte were flowing over the sensor. The results
obtained were also discussed. The theoretical and experimental studies have shown that there was
electronic friction and electron drag effect of carbon nanotubes in flowing liquids. This effect in
carbon nanotubes can be used for a new flow sensor.
Investigation on Chaining of Au/Aniline Polymerid Nanocomposites with Different Electrodes Configuration and Characterization
Authors: Sun J.F. , Guo Zhi Rui , Gu Ning
Published: March 2009

A dumbbell-liked organ-metal composite was prepared with wet
chemistry. Then the solution was subjected to AC e-field. Herein, three types of
electrodes configuration were adopted to align the colloids. Theoretically, quasi
one-dimensional structures should be observed, and it was the case in the third
configuration. SEM, AFM and TEM were utilized to characterize the resultant
morphology. The mechanism was described with dielectrophoresis theory.
Organic Solvent and Acid Induced Conformational Modification of Model Peptide : Lysozyme
Authors: Sirikun W. , Vardhanabhuti N. , Sutanthavibul Sutanthavibul
Published: March 2009

The conformational modification of model peptide (lysozyme), which was
solubilized in various concentrations of aqueous-ethanolic solutions (0-99% v/v), were
characterized by circular dichroism and fluorometry. It was found that at 80% v/v ethanol,
lysozyme changed its conformation to molten globule (MG) state. After HCl was introduced to
achieve a solution of pH~2, only 35% v/v ethanol was required in order to initiate MG state.
However, MG state was not generated when acidic solution was used alone without ethanol.
This conformational change from native state to MG state was found to be reversible by simple
aqueous dilution.
Comparison of Adsorption Behaviour for Fibrinogen and Albumin on Single Walled Carbon Nanotubes Nonwoven
Authors: Meng Jie , Song Li , Zhong Jun , Wang Chao Ying , Kong Hua , Wu Zi Yu , Xu Hai Yan , Xie Si Shen
Published: March 2009

Fibrinogen and albumin are two of the most important plasma proteins that relate to
blood coagulation caused by engineered surfaces. In this paper, the adsorption behavior of albumin
and fibrinogen on single-walled carbon nanotubes nonwoven (SWNT nonwoven) was investigated
through scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), near edge
X-ray adsorption fine structure spectroscopy (NEXAFS) and direct enzyme-linked immunosorbent
assay (ELISA) respectively. It was concluded that SWNT nonwoven displayed strong adsorption
preference of fibrinogen to albumin. In addition, the immune activity of fibrinogen adhered to the
SWNT nonwoven surface was found remained and showed a linear response to the concentration in
a certain range.
Investigation of Micro-Tribological Behavior of MS2 Nanotubes
Authors: Li Chang Sheng , Yan Ke Hong , Li Jun Mao , Shen Xiao Ping , Chen Kang Min
Published: March 2009

It is well known that metal dichalcogenides MS2 (M=Mo, W, Nb, Ta, TiS, Zr ,Hf, S=S, Se)
have lamellar structure, the bonds of adjacent lamellae are weak van der Waals interactions and
inter-lamellar are strong covalent interactions. The structures make adjacent lamellae easy to slip and
it shows low friction coefficient during friction process. MS2 are often used as solid lubricants in
high/low temperature, heave load and vacuum, in which oil is failure. WS2 has better high
temperature properties than MoS2, although little natural WS2 mineral has been deposited, and people
must synthesize it by chemical means, so its price is nearly 5 times expensive than that of MoS2. Until
now little study is made comparing with MoS2. Furthermore the research papers about tribological
behavior of NbS2, TaS2, TiS2, ZrS2, HfS2 are not seen. In this study the thermal decomposition
method is used to produce fullerene-like MS2 nanotubes. The morphology, microstructure and
tribological behavior of MS2 nanotubes are investigated by means of SEM, TEM, XRD and AFM.
The results show that the diameter of MoS2, WS2 and NbS2 nanotube is less than 100nm, and the
length is more than 2μm. The MoS2, WS2 nanotube has lower friction coefficient than MoS2 powder
tested by AFM using Si3N4 probe. Similar results are also found for NbS2 nanotube. The
macroscopic friction test for pin on disc tester shows nearly the same results. TEM image shows that
MS2 nanotubes have rolling debris between two antagonist surfaces, and MoS2 powder only has
flattened debris. It may be the fullerene structure brings the chemical stability and lead low friction.
Synthesis and Optical Characterizations of ZnO Nanorods
Authors: Li Chun Ping , Lv Yu Zhen , Guo Lin , Xu X.B. , Ai X.C. , Zhang J.P.
Published: March 2009

Monodisperse wurtzite ZnO nanorods with the length of 4 μm and the diameter of 200
nm were prepared via a simple solution chemical process. The crystal phases and the microstructure
of nanorods were studied via XRD, SEM, respectively. The properties of the excitonic
luminescence are investigated by using the laser power dependence and temperature dependence of
photoluminescence (PL) spectra.
Six-DOF Nanomanipulation Tools for Nanoscale Device Prototyping and Fabrication
Authors: Zhu Zhen Qi , Cui Hong Liang
Published: March 2009

With the progress of instrumentation in nanoscale visualization, tremendous
sicentific dicoveries and understanding has been made. A great breakthrough in
nanotechnology came with the inventions of scanning tunneling microscope in 1982 and
atomic force microscope in 1986. These revolutionary inventions opened the nanoworld to
scientists and engineers by visualizing it with atomic resolution. However, the lack of
efficient nanomanipulation capability has become a bottleneck for creating devices using
nanocomponents both in the research community and industry. This paper presents the stateof-
the-art of nanomanipulation concepts, manipulator designs, manipulator systems. Such an
approach has certain advantages over existing designs which have such limitations as device
sizes orders of magnitude too large for in situ applications and further device miniaturization
restricted due to the adverse effect of physical scaling laws.
Absorbing Manganese Oxide on Multi-Walled Carbon Nanotubes
Authors: Huang Xian Ping , Pan Chun Xu
Published: March 2009

A layer of Manganese dioxides (γ-MnO2) was absorbed upon carbon nanotubes
(CNTs) surface by using a chemical deposit process. The morphologies of the MnO2/CNTs
composite were characterized using transmission electron microscopy (TEM), energydispersive
X-ray spectrometry (EDS), X-ray diffraction (XRD) and laser Raman spectroscopy
(RS). It is found that absorbed layer belongs to the γ-MnO2 nanoparticles in size about 10 nm,
and coated homogeneously around the CNTs. It is expected that this MnO2/CNTs composite
will be widely applied to make supercapacitors.
A Molecular Tool for Carbon Transfer in Mechanosynthesis
Authors: Drexler K.Eric
Published: March 2009

Proposed advanced mechanosynthetic systems [1] require molecular tools able
to bind and transfer reactive moieties with high reliability at 300 K (failure rates << 10–10
per transfer operation). Screening of a large number of candidate tools at the AM1 level
enabled the identification of a structure, DC10c, that is calculated (at the B3LYP/6-
31G(d,p) level) to meet these stringent requirements when used to transfer carbon dimers
to any of a target class of graphene-, nanotube-, and diamond-like structures [2]. The
favorable energy of transfer (exoergic by a mean energy ≥ 0.261 aJ per dimer) results
from avoidance of the generation of high-energy radical sites during dimer release by
means of π-delocalization to form a strained aromatic ring on the binding face of the
empty structure. These energies are compatible with transfer-failure rates ~ 10–24 per
operation at 300 K, and overall failure rates << 10–10.
Effect of Crystal Size on the Magnetic Entropy Change in CoCr2O4
Authors: Li Shang Dong , Huang Zhi Gao , Zhao Guo Xia , Zou Wen Qin , Zheng You Liao , Du You Wei
Published: March 2009

The size effect of magnetocaloric effect (MCE) in CoCr2O4 has been investigated by
comparing two samples with different crystal sizes. One is bulk CoCr2O4 sample (referred as A),
and the other is a nanocrystalline CoCr2O4 sample (referred as B). It has been found that crystal size
dramatically affects the magnetic properties and MCE for CoCr2O4, and that the nanocrystalline
material is more favorable for application than the bulk material. The above results are explained in
terms of the effect of small size and its distribution for sample B on the intrinsic magnetic
properties and magnetic entropy change.
Aided Sintering Behaviour of Nano Hydroxyapatite Particles
Authors: Ruan C.X. , Gao Wei Min , Zhao R.F. , Chen Yun Fa , Xie Y.S.
Published: March 2009

To avoid microcrack formation caused by the addition of heterogeneous sintering aids, nano
hydroxyapatite powder was prepared by precipitation method and doped into commercial
hydroxyapatite powders as homogeneous sintering aid. Gelcasting method was used to prepare these
hydroxyapatite green bodies. Densification of the blended powder was performed by pressureless
sintering in air atmosphere at the range 1100°C to 1400°C for 2h, with a step size of 50°C. The
results showed that the nano particle can greatly improve the densification process of the green
bodies, and at 1300°C, which is the highest sintering temperature for hydroxyapatite without
decomposition in the air atmosphere, the relative sintering densities of the doped green bodies and the
ones without doping were 93.99% and 83.13% respectively.
Biomimetic Synthesis of Nanoporous Silica Templated by Copolypeptide in the Organic Gel System
Authors: Liu Y.P. , Shen Z.R. , Li L.Y. , Sun P.C. , Yuan Zhong Yong , Chen Tie Hong , Li B.H. , Ding D.T.
Published: March 2009

At neutral pH value and room temperature, nanoporous silica has been prepared through
self-organization of synthetic block copolypeptide Poly(ethyl glycol)-b-poly(L-phenylalanine)
(MPEG44–b-Phe7) and silicane in the organic gel system. In this system, π－π interaction between
anilino-methyl triethoxy silicane and block copolypeptide MPEG44–b-Phe7 effectively controlled the
growth of the silica precursors. SEM images show that the size of silica is relatively uniform with the
length ranging from 20~50 μm and the diameter ranging from 2~5 μm. FT-IR spectra reveals that
there exists nanoporous structure in the calcined sample. N2 adsorption-desorption isotherms are
consistent with the results of FT-IR spectra and show a type-IV isotherm with H1-type hysteresis
loop, which means the presence of uniform nanoporous structure. This sample has a BET surface area
of 171 m2.g-1 and a pore volume of 0.55 cm3.g-1. The average pore size calculated by BJH method is
10 nm. Our results suggest a new biomimetic avenue for synthesis of nanoporous inorganic materials
templated by the self-organization of copolypeptide .
Electrical Conductivity and Low-Field Magnetoresistance in La2/3(Ca0.60Ba0.40)1/3Mn1-xVxO3 Prepared by Sol-Gol
Authors: Zhang Hong , Chen Shui Yuan , Tang Su Zhen , Ke Wen Pao , Lai Heng , Huang Zhi Gao
Published: March 2009

La2/3(Ca0.6Ba0.4)1/3Mn1-xVxO3 (x=0, 0.03, 0.05, 0.07, 0.10, 0.15, 0.20) nanoparticles were
synthesized using sol-gel technology. The experimental results reveal that, (1) the substitution of V
for Mn in La2/3(Ca0.6Ba0.4)1/3Mn1-xVxO3 lowers the Curie temperature TC and the metal–insulator
transition temperature TMI; (2) there exists the evident difference between the TC and the TMI for
different V substitution ratio; (3) the low-temperature tunneling magnetoresistance and maximum
magnetoresistance near Tc increase with the enhancement of V-doping content. Based on the
tunneling magnetoresistance model and the percolation model near Curie temperature, the
experimental results are explained well.
Femtosecond Transient Absorption Spectroscopy of Single-Walled Carbon Nanotubes and their Ultrafast Optical Switching Behavior
Authors: Yang J.P. , Kappes Manfred M. , Hippler H. , Unterreiner Andreas N.
Published: March 2009

Two types of individualized single-walled nanotubes (SWNTs) in aqueous surfactant
suspensions have been studied by femtosecond two-color absorption spectroscopy. A careful
selection of pump and probe wavelengths allows for the determination of the “intrinsic” lifetimes of
the lowest excited states which depend on the diameter of the SWNTs. Furthermore, a fast decay
component in the ps to sub-ps regime was also observed and tentatively attributed to bundle
relaxation. Likewise, this experimental approach can also assess spectral regions with decays faster
than 1 ps, which is of great interest for all-optical switching devices near the optical telecommunication
wavelength.
Elastic and Piezoelectric Characteristics of Wurtzite GaN/AlN Semiconductor Quantum Dots
Authors: Cai L. , Lu Yan Wu
Published: March 2009

The elastic deformation and piezoelectric field in GaN /AlN/ quantum dots have been
investigated. The electronic levels of quantum dots have been given in this paper. The 3D strain
field and piezoelectric potential are calculated based on and the effective mass theory and finite
element method. The effect of spontaneous and piezoelectric polarization is taken into account in
the calculation. The ground bound state and the several lowest excited states of quantum dots have
been studied. It is found that the size of quantum dots controls the conduction band edge, electronic
levels and more other optical properties. The calculation results are very helpful in designing high
quality infrared photodetector and laser.
Optical Tunable Properties of Semiconductor Compound ZnxCd1-xS Incorporated in the Channels of Nanoporous VSB-5 Crystals
Authors: Jian Dun Liang , Gao Qiu Ming , Gao Dong Mei
Published: March 2009

ZnxCd1-xS (x = 0~1) nanoparticles were prepared in the channels of nanoporous VSB-5
(Versailles Santa Barbara-5) by introducing metal ions in the channels and followed by
vulcanization. ZnxCd1-xS nanoparticles and VSB-n displayed their own spectra properties. However,
ZnxCd1-xS nanoparticles demonstrate obvious blue-shift and tunable property in the UV-vis
absorption spectra due to the quantum confinement effects.
Carbon Nanotubes Synthesized by Rapid Quenching of Red-Hot Graphite Rod in Ethyl Alcohol
Authors: Zou Xiao Ping , Abe H. , Shimizu Toru , Ando A. , Tokumoto H. , Zhu S.M. , Zhou Hao Shen
Published: March 2009

In order to meet the requirements of various applications, considerable efforts have been
focused on the new approaches for synthesizing carbon nanotubes. Recently, simple thermal
chemical vapor deposition growth technique by pyrolyzing ethyl alcohol has been developed.
However, this method needs metallic catalyst. Here, we demonstrate that it is possible to synthesize
multi-walled carbon nanotubes without the aid of any catalyst. The as-synthesized products were
analyzed by high-resolution transmission electron microscopy (HRTEM). The HRTEM images show
that the products are straight multi-walled carbon nanotubes. The synthesis technique of carbon
nanotubes is cost-effective because of the catalyst-free process.
Raman Quantitate Stress in Nano-Thin Film of MEMS
Authors: Sang Sheng Bo , Xue Chen Yang , Zhang Wen Dong , Zhang Bin Zhen
Published: March 2009

The stress is an important parameter of nano-thin film of the micro-structure. It is essential
for the successful design and operation of many micro-machined devices. In this paper, the
experiment idea that using Raman spectrometer to quantitate the stress in the nano-thin film of
MEMS was put forward and the formula of the stress of Si and GaAs crystal was derived. In the
experiment, the Si nano-thin film and AlAs/GaAs nano-thin film on GaAs substrate were grown by
MBE (molecular beam epitaxy). The uniaxial pressure is exerted to nano-thin film by using the
pressurization instrument designed by ourselves. Raman spectrums of the nano-thin film of MEMS
are measured with the pressure exerted varying. Through the processing of the experiment data, the
error of measurement to stress in nano-thin film is maximally 0.9% to Si and 7.5% to GaAs. So,
Raman spectrum can be used to accurately quantitate stress in nano-thin film of MEMS in order to
assessment of the reliability of micromachined structure. And the method can be applied to quantitate
the stress in the experiment of testing the piezoresistor effect of double-quantum-well nano-thin film.
Structural Evolution of Nanostructured YBa2Cu3Ox Thin Films Formed by Pulsed Laser Glancing Angle Deposition
Authors: Wang H.H. , Zhao Y.P.
Published: March 2009

Nano-structured thin films of amorphous YBa2Cu3Ox were prepared by pulsed
laser glancing angle deposition. Ambient oxygen pressure and laser fluence have a
strong effect on the microstructure of the films. The films exhibit a structural
evolution from isolated nanorods, through network of vertical nanocolumns, to
nanoparticles fractal with increasing ambient oxygen pressures. Shadowing effect,
surface diffusion and flux scattering by ambient gas play main roles in determining
the structural evolution.
Surface Optic Phonons in Cylindrical and Rectangular Cross-Sectional Semiconducting Nanowires
Authors: Xiong Qi Hua , Gupta R. , Wang J. , Mahan G.D. , Lew Yan Voon L.C. , Eklund P.C.
Published: March 2009

Raman scattering from surface optic (SO) phonons has been observed and identified in
cylindrical and rectangular cross-section nanowires with lateral dimensions in the range 20-50 nm
and lengths of ~ 10 microns. The position of the SO band is found to depend on both the shape of the
wire cross section (i. e., circular or rectangular) and on the dielectric constant of the external medium.
The position of the SO band in GaP and ZnS nanowires is in good agreement with a dielectric
continuum model that takes the shape of the wire cross section into account. We propose that the
symmetry breaking mechanism which activates the Raman sacttering of the SO phonon in our
nanowires is a quasi-periodic modulation of the cross-sectional area along the nanowire axis. We
suggest this modulation stems from an interesting growth instability associated with
vapor-liquid-solid (VLS) growth.
Preparation of β-TCP/TiO2 Composite by Hot-Pressing
Authors: Lee Jong Kook , Jung Hang Chul , Seo Dong Seok , Kim Hwan , Hwang Kyu Hong
Published: March 2009

In this work, tricalcium phosphate [TCP, β-Ca3(PO4)2]/titania composite were prepared
with different ratio of 75/25, 50/50 and 25/75 (HA/TiO2, wt %). The TiO2 and hydroxyapatite (HA)
powders, as starting materials, were synthesized by precipitation and hydrothermal methods,
respectively. The sintered bodies of β-TCP/TiO2 composite were prepared by hot pressing at pressure
of 30 MPa and temperature of 800-1000 oC for 30 min under the pressure of 30 MPa in N2 atmosphere.
During the sintering process, hydroxyapatite was decomposed to β-TCP and CaTiO3 at elevated
temperature because TiO2 could accelerate the decomposition of hydroxyapatite. The hot-pressed
composite with 98% of sintered density, showed high value of 1080 Hv in hardness, compared with
the pure hydroxyapatite (600 Hv) before immersion in distilled water. Increasing sintering
temperature led densification of the composite with moderately uniform microstructures. As
increasing the amount of TiO2, the surface of the composite was less damaged or dissolved.
Surface Dissolution of Hydroxyapatite with Different Composition
Authors: Seo Dong Seok , Kim Hwan , Lee Jong Kook
Published: March 2009

The effect of Ca/P ratio on surface dissolution of hydroxyapatite [Ca10(PO4)6(OH)2, HA] in
distilled water was investigated. The stoichiometric HA powder and desired Ca/P ratio achieved by
adding either Ca3(PO4)2 for a Ca/P ratio of 1.62 or CaO for a Ca/P ratio of 1.72 were used as starting
materials. Dense HA ceramics were obtained by sintering at 1200 oC for 2 h in air with under
moisture protection. The sintered specimens were then placed into 40 ml of pH 7.4 distilled water.
After immersing for certain period of time at 37 oC, crystal structure, weight loss and microstructure
of the specimens were investigated. As increasing the immersion time, circular cavities similar to that
normally attributed to osteoclast resorption lacunae were observed. As a result, it was found that the
dissolution of HA along the grain boundary and subsequently microstructural disintegration was
more distinct in 1.62 and 1.72 samples compared to pure HA.
X-Ray Spectra of Hydrogen-Like and Helium-Like Argon Ions on Solid Surfaces
Authors: Yang Z.H. , Chen X.M. , Zhang Y.P. , Zhang X.A. , Zhao Y.T. , Cui Y. , Zhang H.Q. , Xu X. , Shao J.X. , Su H. , Xiao G.Q.
Published: March 2009

14-GHz electron cyclotron resonance ion source at the Heavy Ion Research Facility
National Laboratory in Lanzhou has been used to investigate x-rays from the interaction of slow
highly charged Ar17+and Ar16+ions for different energies with Be, Al, Ni, Mo and Au surfaces.
Interaction of Ar17+ and Ar16+ ions with Metallic Surfaces for a wide range of energies has been
studied by measuring the resulting x-ray emission. The characteristic features of the x-ray spectra
have been explained.
Kinetic Energy Effect in the X-Ray Emission of Mo Surface Induced by Xe28+ Ions
Authors: Chen X.M. , Cui Y. , Yang Z.H. , Xu J.Z. , Zhang H.Q. , Xu X. , Shao J.X. , Liu Z.Y. , Xiao G.Q. , Zhang X.A. , Zhao Y.T. , Zhang Y.P.
Published: March 2009

L-shell x-ray spectra of Mo surface induced by Xe28+ were measured with a Si(Li)
detector. The x-ray intensity was found increased rapidly with the kinetic energy of the incident ions.
The relation of x-ray intensity with kinetic energy of the projectile is discussed. There is a turning
point of the intensity to the kinetic energy, and the explanation is given.
Low Temperature Sintering of AlN-SiC-TiB2 System for the Fabrication of Continuous Fiber Reinforced Ceramic Composites (CFCC)
Authors: Lee Sea Hoon , Tanaka Hidehiko , Nishimura Toshiyuki , Guo S.Q. , Kagawa Yutaka
Published: March 2009

We report sintering additive systems to decrease the densification temperature of the
corrosion resistant AlN-SiC-TiB2 system. Since oxide additives degrade the high temperature
properties of the system, and other kinds of metallic additives may affect the formation of protective
mullite during oxidation, only the constituent elements were applied as additives. Dense samples ( >
98 % relative density) could be fabricated at 1850 oC and 1900 oC by spark plasma sintering (SPS)
and hot pressing method, respectively.
Synthesis and Electrorheological Characteristics of Conducting Polymer/Clay Nanocomposites
Authors: Sung Jun Hee , Choi Hyoung Jin
Published: March 2009

Nanocomposites of conducting polymers of polyaniline (PANI), poly(oethoxyaniline)
(PEOA) and polypyrrole (PPy) with clay prepared via either in-situ emulsion
polymerization or solvent intercalation were investigated especially for electrorheological fluid
(ER) application. Internal structures of these nanocomposites were examined via wide angle X-ray
diffraction (WAXD), and transmission electron microscope (TEM). The intercalated nanostructures
analyzed via WAXD and TEM were correlated with the electrical property change originated from
the nanoscale interaction between clay and conducting polymer. Moreover, their ER behaviors were
measured via rotational rheometer with external electric field controller.
Fabrication of 4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates
Authors: Yim Jeong Hyuk , Song Ho Keun , Moon Jeong Hyun , Seo Han Seok , Lee Jong Ho , Na Hoon Joo , Lee Jae Bin , Kim Hyeong Joon
Published: March 2009

4H-SiC planar MESFETs were fabricated using ion-implantation on high-purity
semi-insulating substrate, and their DC and RF performances were characterized. A modified RCA
method was used to clean the substrate before each procedure. Sacrificial oxide was grown after
channel layer etching to eliminate plasma damage to the gate region. A thin, thermal oxide layer was
grown to passivate the surface and then a thick field oxide was deposited by CVD. The maximum
oscillation frequency of 26.4 GHz and the cut-off frequency of 7.2 GHz were obtained. The power
gain was 8.4 dB and the output power was 2.8 W/mm at 2 GHz.
Single Crystal PMNT/Polymer 1-3-2 Piezoelectric Composites
Authors: Wang Li Kun , Li Shu Xiang , Qin Lei , Du Hong Liang , Li Li
Published: March 2009

Lead magnesium niobate-lead titannate single crystal (abbreviated as PMNT) was used
to fabricate PMNT/polymer 1-3-2 piezoelectric composite with different volume fractions of PMNT,
by dicing single crystal PMNT along mutually perpendicular two directions on the surface and then
filling polymer into grooves. The piezoelectric, dielectric and electromechanical properties of the
novel composite were determined. It was demonstrated that a thickness electromechanical coupling
coefficient of the composites could reach as high as 0.75 and acoustic impendence decreased to
14.9 Mrayls (lower than 30 Mrayls of PMNT). The pulse-echo waveforms of the composites
without backing were also measured. It showed a -6dB bandwidth of 88% at the center frequency of
0.95MHz.
Growth and Characterization of GaN Nano-Column Grown on Si (111) Substrate Using Au+Ga Alloy Seeding Method by MOCVD
Authors: Shim Byung Young , Ko Eun A , Kim Dong Wook , Lee Cheul Ro
Published: March 2009

We have studied the Au+Ga alloy seeding method. Single-crystal GaN nano-column arrays were
grown using metalorganic chemical vapor deposition (MOCVD) and their properties were investigated as
a function of the growth parameters and Au thin film thickness. Au-coated Si(111) substrates were used
for the growth of GaN nano-columns. The diameter and length of as-grown nano-column ranged from
100 to 500 nm and 1 to 5 μm, respectively. The morphology of the columns was investigated using
scanning electron microscopy. Energy dispersive X-ray spectroscopy and photoluminescence were used
for evaluating of its qualitative analysis and to evaluate the optical properties, respectively. Two
important growth parameters were considered, the thickness of the Au thin film and the gallium flow rate.
The density and tendency of the nano-columns depend on each of these growth parameters. It is believed
that the catalytic activity of gold is determined by the size of the Au+Ga solid solution particles, and
smaller Au+Ga clusters showed significant reactivity in the growth of one-dimensional GaN nano
structures.
Comparison of Semiconductor Radiation Detectors for Large Area X-Ray Imaging
Authors: Choi Chi Won , Park Ji Koon , Kang Sang Sik , Cho Sung Ho , Kim Kyung Jin , Park Sung Kwang , Choi Heung Kook , Kim Jae Hyung , Nam Sang Hee
Published: March 2009

We have developed a large area, flat panel detector for general applications to digital
radiology. This paper presents the x-ray detection characteristics with various semiconductor
radiation detectors (HgI2, PbI2, PbO, CdTe) derived by a novel wet coating process for large area
deposition. The wet coating process could easily be made from large area films with printing paste
mixed with semiconductor and binder material at room temperature. X-ray performance data such as
dark current, sensitivity and signal to noise ratio (SNR) were evaluated. The HgI2 semiconductor was
shown in much lower dark current than the others, and also has the best sensitivity. In this paper,
reactivity and combination characters of semiconductor and binder material that affect electrical and
x-ray detection properties would be verified through our experimental results.
Solvothermal Preparation of Nano-Sized CaWO4 Particles
Authors: Kaowphong Sulawan , Thongtem Titipun , Thongtem Somchai
Published: March 2009

CaWO4 was prepared by solvothermal reaction of Na2WO4.2H2O and calcium salts
(CaCl2.2H2O, Ca(NO3)2.4H2O and Ca(CH3COO)2) in solvent containing a variety of glycerol/water
ratios at 160 oC for 6 h. By using XRD, SEM, TEM and ED, the products compose of nano-sized
CaWO4 particles with scheelite structure but different morphologies. Interplanar spaces between
(101) planes were determined from HRTEM image, ED patterns and XRD spectra are 0.424, 0.474
and 0.476 nm, respectively. Luminescent intensities of the products prepared in pure water are the
highest and their central peaks are the same at 444 nm. In addition, Ca, W and O were detected
using EDX.
SnO2 Nanostructures Synthesized on Co Substrates
Authors: Kim Hyoun Woo , Shim S.H. , Hwang Hae Jin , Shim Jae Hyun , Cho Nam Hee , Park Mi Kyoung , Lee Hyuck Mo , Ahn Byung Tae , Jeon Hyeong Tag , Park Jong Wan , Ahn Jin Ho , Hur Bo Young
Published: March 2009

This study reported the fabrication of tin oxide (SnO2) nanostructures on Co-coated Si
substrates by the thermal heating of Sn powders. The microstructures and morphologies of the
resultant nanostructures were studied by means of X-ray diffraction (XRD), transmission electron
microscopy (TEM), selected area electron diffraction (SAED), and scanning electron microscopy
(SEM). The product mainly comprised the tangled nanowires with average diameters in the range of
50-180 nm. The nanostructures were single-crystalline rutile structure of SnO2. The PL measurement
with the Gaussian fitting exhibited visible light emission bands centered at 576 nm and 638 nm,
respectively. We have discussed the possible growth mechanism of the nanostructures.
Fabrication of Size Controlled Nanohole Array on III-V Semiconductor Substrate by ICP-RIE Using Nanoporous Alumina Mask
Authors: Jung Mi , Lee Seok , Byun Young Tae , Jhon Young Min , Kim Sun Ho , Mho Sun Il , Woo Deok Ha
Published: March 2009

Formation of size controlled nanohole arrays on semiconductor substrate can be used
variously in applications of photonic and electronic device. The unique structure of nanoporous
alumina was directly used as an etching mask for pattern transfer into the GaAs substrate. Using the
alumina masks prepared at the anodic voltage of 24 V in 0.3 M sulfuric acid solution and 40 V in 0.3
M oxalic acid solution, fabricated were the arrays of nanohole on GaAs substrate by inductively
coupled plasma reactive ion etching (ICP-RIE). The etching was conducted in a SiCl4/Ar mixed gas
system. The uniform nanohole arrays were formed as replica of ordered lattice pattern of the mask.
Depending on property of the alumina mask used, the size of nanohole was controlled to have hole
diameter of 60 nm (with the hole density of 1.0 x 1010 cm-2) and of 30 nm (with the hole density of 2.7
x 1010 cm-2), respectively. So, the alumina mask attached on the GaAs substrate mainly determines the
distribution and the size of the nanohole arrays. ICP-RIE using nanoporous alumina masks can
control the size and the density of nanohole on compound semiconductor substrate.
Effect of Nanoscale Multilayered Structurization on Hardness and Wear Resistance in Al-Cr-N Coating
Authors: Park Jong Keuk , Chung Yong Hwa , Kim Young Do , Baik Young Joon
Published: March 2009

Al-Cr-N coatings were deposited on Si substrate by unbalanced magnetron (UBM)
sputtering with Al and Cr targets and Ar and N2 reactive gases at substrate bias of -50V. At a fixed
chamber pressure of 0.8 Pa, the microstructure of the coatings was changed from AlN/CrN nanoscale
multilayered structure to (Al,Cr)N mixed single layered one with the increase of rotation speed of
substrate holder. The residual compressive stress of AlN/CrN nanoscale multilayered coating was
higher than that of (Al,Cr)N single layered coating. For the AlN/CrN nanoscale multilayered coating,
the residual compressive stress was reduced with increase in total pressure of reactive gases. The
AlN/CrN nanoscale multilayered coatings with higher residual compressive stress showed higher
hardness and wear resistance.
Fatigue Crack Propagation Behavior of Friction Stir Welded 6061-T651 Al Alloy
Authors: Hong Seong Jin , Kim Sang Shik , Lee Chang Gil , Kim Sung Joon
Published: March 2009

Fatigue crack propagation (FCP) behavior of friction stir welded (FSWed) 6061-T651 Al
alloy was examined with the fatigue crack growing either along the dynamically recrystallized zone
(DXZ) at variable K or perpendicular to the DXZ at a constant K value of 7.5, 10 and 15 MPa√m,
respectively. The FCP rates in the DXZ tended to be significantly lower than those in the PM
particularly in low K regime. Compressive residual stress reducing effective K cannot be solely
responsible for the enhanced FCP resistance. The fine recrystallized grains in the DXZ causing
intergranular fatigue failure appeared to be detrimental to the FCP behavior of FSWed 6061-T651
specimen. The constant K fatigue test across the weld zone showed that substantial crack
retardation occurred far beyond the heat affected zone (HAZ) at low K regime. The FCP behavior of
FSWed 6061-T651 is discussed based on residual stress measurement and fractographic observation.
Effect of Vibration during Welding on the Fatigue Strength of Structural Steel Weldments
Authors: Lee Chin Hyung , Jang Gab Chul , Park Hyun Chan , Chang Kyong Ho
Published: March 2009

During repair welding of steel bridge under service load, vibration occurs due to the
dynamic loads like wind and vehicles, etc. However, the effect of vibration during welding on the
fatigue strength of weldments is not yet clearly understood. In this paper, the effect of vibration
during welding on the fatigue strength of structural steel weldments was investigated in order to
improve reliability in the repair welded joints of steel bridge. The base material used in this
investigation was SM 490A steel of weldable grade. Flux Cored Arc Welding (FCAW) process was
used to fabricate the single ‘V’ butt joints. Welding was performed on the steel under the
mechanical vibration of given frequency. The applied frequency was resonant frequency. Also,
weldments under no vibration during welding were prepared. Fatigue tests were conducted using a
servo hydraulic controlled 50tonf capacity UTM with a frequency of 5Hz under constant amplitude
loading. Effect of vibration during welding on the fatigue strength of weldments was analyzed in
detail.
TEM & EBSD Study on Deformation Behavior of High Nitrogen Austenitic Fe-18Cr-18Mn-2Mo-0.9N Stainless Steel
Authors: Lee Tae Ho , Kim Sung Joon , Kang Suk Hoon , Oh Kyu Hwan , Takaki Setsuo
Published: March 2009

Deformation behavior of high nitrogen austenitic Fe-18Cr-18Mn-2Mo-0.9N stainless
steel was investigated utilizing electron back-scattered diffraction (EBSD) and transmission electron
microscopy (TEM). During deformation, the <110> grains rotated and the trace of these grains
moved towards into the dodecahedral plane (the line connecting (001) and (111) planes).
Misorientation mapping in EBSD showed that the special boundaries (almost Σ3) gradually
diminished whereas the low-angle boundaries were developed. TEM observation showed that (i) the
low-angle boundaries developed corresponded to the deformation twinning with {111}<112>
component, (ii) the deformation twinning showed the strong orientation dependence relative to
tensile axis, and (iii) the deformed microstructure was characterized by extended stacking faults,
planar dislocation array in low strain regime, and by well-developed deformation twinning in high
strain region, respectively.
Influence of ECAP Routes on the Microstructure and Mechanical Properties of Hot Extruded 3003 Al Alloy
Authors: Lee Byoung Soo , Cho Hoon
Published: March 2009

The microstructures and mechanical properties of unidirectional deformation structured Al
alloy during ECAP with various deformation routes were investigated. In order to fabricate
unidirectional deformation structure for Al alloy, hot extrusion was carried out. It was found that the
deformation route A in ECAP routes is the dominant route for the grain refinement and strengthening.
In deformation route A, the high strength ultra-fine grained Al alloy with a grain size of ~ 200 nm was
obtained due to the accumulation of consecutive strain process. In contrast, the strength of ECAP’ed
Al alloy produced via deformation route C was greatly increased after one pass because the grains
were strained and cancelled each pass. By contrast, the equiaxed grains were obtained in deformation
route BC because the sample was rotated 90 O in the same sense in each pass. The deformation route
BC was superior to the deformation route C because the deformation route BC was more favorable
than the deformation route C in the accumulation of consecutive strain. It is also found that
unidirectional deformation structured Al alloy via hot extrusion shows similar grain refinement
tendency with equiaxed structured Al alloy during ECAP processing.
Change of Mechanical Properties of FM Steels after Thermal Aging
Authors: Kim Sung Ho , Han Chang Hee , Ryu Woo Seog
Published: March 2009

The effects of thermal aging on microstructural evolution and mechanical properties are
important in the understanding of the in-service behavior of ferritic/martensitic steels in advanced
nuclear power system. Ferritic/martensitic steels have been aged at 600oC for times up to 20,000 hrs.
The change of mechanical properties has been examined for these aged materials. The strength and
hardness was hardly changed after the thermal aging at 600oC for 20,000 hrs in all specimens. The
impact absorbed energy decreased with the aging time. But the decrease of the impact absorbed
energy was larger at the early stage of aging in tungsten added steels. This is attributed to the
formation of Laves phase. Nitrogen which is known to increase the creep rupture strength had no
effect on the degradation of the microstructure and mechanical properties during thermal aging.
Microstructures and Dielectric Properties of CaCu3Ti4O12 Polycrystalline Ceramics
Authors: Yoo Duk Keun , Yoo Sang Im
Published: March 2009

We report important factors affecting the dielectric properties of CaCu3Ti4O12 (CCTO)
polycrystalline ceramics prepared by the conventional solid-state ceramic process. The relative
dielectric constants (εr) up to several thousands (~ 3,000 at 1 kHz) were gradually increased with
increasing the sintered density of samples in the case that no exaggerated grain growth occurred. An
abrupt increase in εr values were, however, accompanied by the formation of abnormally grown large
grains, and thus with increasing the population of abnormally grown grains, which could be achieved
by a prolonged sintering at 1060°C, the εr values were remarkably increased from several thousands to
~105. Optimally processed CCTO sample exhibited a very high εr of ~ 90,000 at 1 kHz.
The Effects of Processing Temperature and Time on the Surface Properties of Plasma Radical Nitrided SCM 440 Steel
Authors: Lee Insup , Park Ik Min
Published: March 2009

Plasma radical nitriding was performed to harden the surface of SCM 440 steel for 1-10
hours at temperature range of 450-550°C. No compound layer was formed during this process
except the experiment carried out at 500 for 10 hours. A diffusion depth increased with
increasing treatment temperature and time ( up to about 250). The surface hardness of radical
nitrided layer was two times higher than that of the untreated surface. The main phase produced in
the diffusion zone was identified to be γ΄-Fe4(N,C). The residual stress of the diffusion layer also
increased with increasing treatment temperature and time due to the increase of precipitates.
The Effect of Bubbling and AlCuP for Refining Primary Silicon at Al-18%Si Alloy
Authors: Choi Jung Pyung , Kim Won Jung , Nam Tae Woon , Yoon Eui Pak
Published: March 2009

This paper investigates the effect of Bubbling and AlCuP on primary Si size in Al-18%Si
alloy. Bubbling process and AlCuP treatment are effective for refining primary Si in hypereutectic
Al-Si alloy. Both the bubble and AlCuP can be used as nucleation sites of primary Si. Many
nucleation sites can make the size of primary Si decreased. So, this experiment suggests that the mix
using of bubbling process and AlCuP treatment are more effective for nucleation site of primary Si.
For deciding the optimum treatment order, the experiments are processed 3 kinds of order with
varying stirring time and holding temperature; 1)AlCuP treatment and then bubbling process,
2)simultaneously using of bubbling process and AlCuP treatment, 3)bubbling process and then
AlCuP treatment.
Tribological Behavior and Surface Chemistry Characteristics of Quasicrystal Coatings
Authors: Kim Bong-Hwan , Lee Sang Mok , Shin Je Sik , Moon B.M.
Published: March 2009

The aim of this study was to investigate the effects of air plasma spraying process
parameters on the tribological behavior and surface characteristics of quasicrystal coatings. For this
purpose, the response surface method (RSM), one of the designs of experiment (DOE) was utilized to
systematically investigate the combined effects of each process parameters. The RSM analysis
revealed that the superior tribological performance of quasicrystal coatings was obtained by the
optimized condition of specific micro-hardness and porosity level. It was specially quoted that the
relatively low hardness of quasicrystal coatings caused the improvement of abrasive wear resistance
during the current investigation.
Electrochemical Interpretation of a Stress Corrosion Cracking of Thermally Treated Ni Base Alloys in a Lead Contaminated Water
Authors: Hwang Seong Sik , Lim Yun Soo , Kim Hong Pyo , Kim Joung Soo , Thomas Larry
Published: March 2009

Since the PbSCC(Lead stress corrosion cracking) of alloy 600 tubing materials was
reported by Copson and Dean in 1965, the effect of lead on a corrosion film and cracking
morphology have been continually debated. An electrochemical interaction of lead with the
alloying elements of SG tubings was studied and the corrosion products were analyzed. It was
found that lead enhanced the anodic dissolution of alloy 600 and alloy 690 in the electrochemical
test. The lead preferentially dissolved the Cr from the corrosion film of alloy 600 and alloy 690 in
alkaline water. The lead ion seemed to penetrate into the TG crack tip and react with the corrosion
film. A selective Cr depletion was observed to weaken the stability of the passive film on the alloys.
Whereas passivity of Ni became stable in lead containing solution, Cr and Fe passivity became
unstable.
Corrosion Protection of Aluminum Data Line in TFT-LCD Using Chemical Conversion Coating
Authors: Seo Jong Hyun
Published: March 2009

In order to prevent pitting corrosions in aluminum thin film, zirconium incorporated
chemical conversion coating on sputtered aluminum film was studied. Several pretreatment methods
for conversion coating on the thin film were examined. There existed the optimum pretreatment and
coating condition for successful growing of anticorrosive conversion coating layer in a given
aggressive environment. Pit densities of aluminum thin films were significantly decreased with
conversion coating. Electrochemical behaviors of conversion coated aluminum thin film were also
discussed.
Effects of Pretreatment on the Etch Pit Formation during the Electrochemical Etching of Aluminum
Authors: Lee Jae Kwang , Shin Yun Ho , Kang Jin Wook , Tak Yong Sug
Published: March 2009

The effect of chemical pretreatments on the electrochemical etching behavior of
aluminum was investigated with the topographic studies of surface and the analysis of initial
potential transients. Two-step pretreatments with H3PO4 and H2SiF6 result in a high density of
pre-etch pits on aluminum surface by the incorporation of phosphate ion inside the oxide film and
the removal of surface layer by aggressive fluorosilicic acid solution. It generates a high density of
etch pits during electrochemical etching and results in the capacitance increase of etched Al
electrode by expanding the surface area, up to 61.3 μF/cm2 with the pretreatment solution of 0.5M
H3PO4 at 65°C and 10 mM H2SiF6 at 45°C.
Bonding Strength of Top Coat and its Fracture Mechanism in Thermal Barrier Coatings with Thermal Fatigue
Authors: Kwon Jae Young , Jung Yeon-Gil , Chang Jung Chel , Choi Seong Churl , Paik Ung Yu
Published: March 2009

The bonding strength of top coat in thermal barrier coatings (TBCs) with different bond
layers has been measured with thermal fatigue and its fracture behavior has been investigated
considering the effects of a thermally grown oxide (TGO) layer and resintering of the top coat. Two
kinds of TBCs with different thicknesses of approximately 80 and 280 μm in bond layer were
prepared by two different methods of air plasma spray (APS) and high velocity oxygen flow (HVOF).
Top layer (3Y-TZP) was coated on both bond layers using the APS process. Thermal fatigue tests
were conducted at temperature of 1100oC with dwell time of 10 hr, which tests were done till 20
cycles. The HVOF process provides a relatively homogeneous microstructure in the bond layer,
compared with the APS process. The formation of TGO layer is influenced by the exposed time,
independent of the bond layer thickness and the bond layer species. TBCs with the bond layer
prepared by the APS process show higher bonding strength than those by the HVOF process in
as-prepared TBCs (before thermal fatigue), showing 15 – 18 MPa for the APS process and 13 – 16
MPa for the HVOF process. Whereas the fracture in TBCs with the HVOF bond coat are originated at
the interface between the top coat and the bond coat, the fracture within the top coat in TBCs with the
APS bond coat However, after the thermal fatigue, the bonding strength value is increased to 18 – 20
MPa in both cases even though the TGO layer is formed, showing the fracture paths within the top
coat in both cases.