bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Simulation of a Mid-Infrared Quantum Cascade Laser Based on Ge-Si Superlattices
Authors: Lu Yan Wu , Sun Gregory
Published: March 2009

This paper presents a novel valance intersubband laser based on Si-based Si-Ge superlattices
grown on a relaxed Si0.5Ge0.5 buffer layer. Effective mass theory is used to calculate the inplane
valence subband dispersion of Si-Ge superlattices within 6×6 Kane model. Analysis of the inplane
energy dispersion shows that the light-hole effective mass is inverted at off zone center region.
The laser structure can be designed with a simple quantum cascade scheme. Our calculation shows
that with the electrical pump, it is possible to achieve population inversion between the two
subbands at local k space where the light-hole effective mass is inverted. Optical gain of the order
100/cm can be achieved with a pumping current density 10 kA/cm2.
Controlled Drug Release Using Nanoporous Anodic Aluminum Oxide
Authors: Kang Ho Jae , Park Sung Joon , Yoo Ji Beom , Kim Deug Joong
Published: March 2009

Hardening of blood vessels has steeply increased every year, and implantation stent was
used to solve that the conditions of illness. However, in-stent restenosis continues to make problem.
To overcome the problem of in-stent restenosis, the concept of local delivery of antiproliferative or
immunosuppressive drugs has been introduced into interventional cardiology. Local drug delivery
system was demonstrated by using drug-eluting stents coated with nanoporous anodic aluminum
oxide (AAO) used for controlled drug release. Effects of diameter and depth of AAO on the diffusion
characteristics of drug were investigated. 2-deoxyadenosine was tested. AAO pore diameter and
depth showed image by SEM and characterization of diffusion of drug from the AAO nanoporous
pore diameter and depth was carried out using by HPLC (high performance liquid chromatography).
Dye-Encapsulation Selectivity of Amphiphilic Dendritic Boxes
Authors: Liu Cui Hua , Gao Chao , Yan De Yue
Published: March 2009

Amphiphilic hyperbranched polyamidoamine (PAMAM) and poly(sulfone-amine)
(HPSA) were prepared and their dye-encapsulation properties were investigated. Both of them can
carry water-soluble dyes from aqueous solution into chloroform. The selectivity of host to guests and
the influence of interaction between different dyes on loading capacity were also investigated by
performing comparable experiments. Encapsulation capacities are considered to have relationship
with the water-solubility of the hyperbranched polymer core, the polarity difference between the
hydrophilic core and the hydrophobic shell, the molecular structure of dyes, and the interactions
between dyes.
Microcontact Printing of Multiproteins on the GA Modified Glass Substrate and Its Applications in the Research of Immunoassays
Authors: Hou S. , Feng X.Z. , Wang L.K. , Chan Q.L.
Published: March 2009

Microcontact printing (μCP) is a newly developed bioresearch technique
applied in many fields such as absorption of proteins, adjunction and growth of cells
and so forth, because of the controllable structure of its patterned materials. Further
experiments showed that the microcontact printed proteins and cells can keep their
bioactivity, which provides a feasibility of bio-molecule or cell analysis. The
self-assembled molecules of μCP make molecule-scaled reactions possible, which
have much higher accuracy compared with large amount reactions in solutions. In this
article we first modified the chemical treated slide with APTES
(3-aminopropyltriethoxysilane) to form AP-glass substrate, then with GA
(glutaraldehyde) to form a GA-AP-glass substrate, and at last used XPS (X-ray
Photoelectron Spectroscopy) technique to show the chemical structure changes of the
surface molecules. Next, using μCP，we patterned chicken IgG (Ag1) and rabbit IgG
(Ag2) onto the GA-APTES-glass substrate in vertical directions. After incubating the
substrate with BSA (bovine serum albumin, a kind of protein) to block the blank place,
we exposed the substrate to Anti-Chicken-IgG-FITC (Ab1) and
Anti-Rabbit-IgG-TRITC (Ab2). Because of the specific binding between Ab and Ag,
through fluorescence microscopy we could see the two-colored fluorescence images
on the GA-AP-glass substrate, in which the different colored strands were vertical
patterned.
The Biological Effect of Iron Oxide and Its Hydrate Nanoparticles
Authors: Zhao Qiang , Pang X.F. , Liu Le Wei , Deng Bo
Published: March 2009

Iron oxide and its hydrate nanoparticles were synthesized by hydrothermal method and
confirmed by infrared and SEM (Scanning Electron Microscope) et al. The dimensions of the
nanoparticles are about 50-120 nm. The crystalline form of iron oxide nanoparticles is like
globosity while its hydrate rod. Amino acids intermingling with the synthesized nanoparticles were
crystallized to investigate the space effect of the nanoparticles. The crystalline forms of crystal are
different to that of pure amino acid. The positions and width of the nanoparticles’ peaks in the
infrared spectrum are changed too. Microscope observation and infrared spectrum results indicated
the nanoparticles had changed the internal structure of amino acids crystal. To considerate the
toxicity of the synthesized nanoparticles, MTT (3-(4,5-dimethylthiazol 2-yl)-2,5
diphenyltetrazolium bromide) assay was used to determine their cytotoxicity. The OD value
(Optical Density) was used to calculated RGR% (Relative Generation Rate) of cells, which
determined the grade of cytotoxicity. The RGR of nanoparticles of iron oxide and its hydrate are
about 1 to 2, which indicate they have just low toxicity.
Preparation of Chitosan Nanoparticles for Protein Delivery by w/o/w Emulsion Solvent Evaporation and Simple Ionotropic Gelation Techniques
Authors: Ritthidej Garnpimol C. , Pichayakorn W. , Kusonwiriyawong Chulalongkorn , Lipipun V.
Published: March 2009

The purpose of this study was to prepare chitosan nanoparticles (CS NP) for controlled
protein delivery. Two techniques, simple ionotropic gelation (method [I]) and w/o/w emulsion
solvent evaporation containing ionotropic gelation (method [II]), were used to prepare CS NP.
Tripolyphosphate (TPP) and Eudragit L100-55 (Eud) were used as anionic agents to form complex
with cationic chitosan. Bovine serum albumin (BSA) was encapsulated into NP. The morphological
characteristics, particle size and size distribution, protein entrapment efficiency, zeta potential, in
vitro release, protein secondary structure and its integrity were investigated. The results showed that
CS NP could be prepared by appropriate cationic and anionic ratios in both methods. Excess anionic
agents resulted in particle aggregation of micron size. The median sizes of particles were between
0.127-0.273 mcm with method [I] provided the smallest size. The 0.02-0.10% BSA loaded
preparations showed the same particle sizes and size distributions as blank preparations. SEM
photomicrographs revealed that the obtained NP were spherical. Protein entrapment efficiency was
between 47-84% and increased when decreasing the percentage of drug loading. The method [II] with
TPP exhibited the highest protein entrapment efficiency, following by the method [II] with Eud and
method [I] with TPP, respectively. The zeta potentials were positive. Prolonged in vitro protein
release profiles were observed from all preparations of CS NP. After 10 days, the release was
between 53-72%. Circular dichroism and SDS-polyaceylamide gel electrophoresis techniques
confirmed that these processes did not have any destructive effect on the protein structure. Therefore
these preparation techniques could be used to encapsulate water-soluble drugs, proteins, DNA, or
antigens into CS NP as effective delivery carriers.
Fabricating Nanofluidic Channels and Applying them for DNA Molecules Study
Authors: Wang Kai Ge , Wang Peng Ye , Yue Shuang Lin , Jin Ai Zi , Gu Chang Zhi , Niu Han Ben
Published: March 2009

In the emerging field of nanobiotechnology, further downsizing the fluidic channels
and pores to the nanometer scale are attractive for both fundamental studies and technical
applications. The insulation Silicon nitride membrane nanofluidic channel arrays which have
width ~50nm and depth ~80nm and length ≥20μm were created by focused-ion-beam instrument.
The λ-DNA molecules were put inside nanochannels and transferred, a fluorescence microscopy
was used to observe the images. Only by capillary force, λ-DNA molecules moved inside the
nanochannels which dealt with activating reagent Brij aqueous solution. These scope nanostructure
devices will help us study DNA transporting through a nanopore and understand more
DNA dynamics characteristics.
Effects of O2 and Ar Reactive Ion Etching on the Field Emission Properties of Aligned CuO Nanowire Films
Authors: Zhu Y.W. , Teo C.H. , Xu X.J. , Yu T. , Lim Chwee Teck , Ong C.K. , Thong J.T.L. , Sow C.H.
Published: March 2009

The effects of oxygen (O2) reactive ion etching (RIE) on the field emission (FE) properties of
aligned CuO nanowire films are investigated systematically. It is found that the FE performance of
the films is largely enhanced after initial exposure to reactive oxygen ions but degrades after
extended treatment. As comparison, Ar RIE is also used to treat CuO nanowires, which, however,
results in the deterioration of FE properties. The enhanced FE after O2 RIE is attributed to the
shaper morphology, cleaner surface and better conductivity. On the other hand, increased work
function and non-crystallized surface structure cause the deterioration of FE of CuO nanowires
after Ar RIE treatments.
Field Emission Characteristics of AlN Coated Silicon Nanocone Arrays
Authors: Shi C.Y. , Wang Qi , Yue Shuang Lin , Gu Chang Zhi
Published: March 2009

Nanoscaled silicon cone arrays were formed on mirror-polished silicon wafers by plasma
etching using hot filament chemical vapor deposition (HFCVD) system. A mixture of CH4 and H2
was introduced during silicon cone formation. AlN films were coated on Si cone arrays using radio
frequency (RF) magnetron sputtering system. Scanning electrons microscopy (SEM) was employed
to characterize the morphology of silicon cone arrays before and after AlN coating. The field
emission characteristics of AlN coated silicon cone arrays，uncoated silicon cone arrays and AlN
films were studied and compared, and the silicon cone arrays with AlN coating showed the best
enhanced electron emission properties due to the negative electron affinity of AlN coating layer and
the high aspect ratio of silicon cone. For AlN coated silicon cone arrays, a slight hysteresis between
the upward and downward voltage sweeps was also observed and the field emission currents from
AlN coated Si nanocone arrays decreased with the increase of the thickness of AlN films, which
could be mainly attributed to the space charge buildup in AlN film with wide band gap.
New p-n Junction Photodetector Using Optimized ZnO Nanorod Array
Authors: Lu Ya Lin , Dajani Iyad A. , Mandeville W.J. , Knize R.J. , Mao S.S.
Published: March 2009

In this research, nanoscale spatial resolution p-n junction photodetector arrays were
developed using ZnO nanorod arrays grown on p-type silicon substrates. In order to optimize the
nanorod array quality, an advanced combinatorial spreadsheet approach was used to optimize the
Au catalyst thickness. The crystallinity of these as-grown ZnO nanorods’ was compared to that of
bulk and thin film ZnO materials.
Field Emission from ZnO by Morphological and Electronic Design
Authors: Xu C.X. , Sun X.W. , Dong Z.L. , Zhu G.P. , Cui Y.P.
Published: March 2009

In this paper, field emission from ZnO was studied by morphological and electronic design. By fabricating ZnO into nanopin
structure with sharp tip, we can obtain low threshold and high emission current density. By doping ZnO with gallium, we can lift up the
Fermi level and increase the conductivity to enhance the field emission. The fabrication of nanostructures and analysis of field emission
will be discussed.
Imaging and Characterization of Self-Assembled Soft Nanostructures by Atomic Force Microscopy
Authors: Souza E.F. de , Teschke O.
Published: March 2009

The atomic force microscope (AFM) obtains its topographical information from the
short-ranged repulsion resulting from the overlap of electronic shells between tip and hard samples.
However, scanning soft samples such as surfactants or biological material within liquid media leads
to a very different scenario due to the long-ranged double layer interactions and the specific tip
penetration through the scanned layers. We show that AFM images and force vs. distance curves can
be used to obtain relevant information on formation, characteristics and behavior of soft
self-assembled nanostructures of surfactants, phospholipids and of cells under physiological
conditions.
Ferroelectric Phase Transition Investigated by Thermal Analysis and Raman Scattering in SrBi2Ta2O9 Nanoparticles
Authors: Ke Hua , Jia De Chang , Wang Wen , Zhou Yu
Published: March 2009

Thermal analysis and Raman spectra were carried out in SrBi2Ta2O9 (SBT) nanoparticles
to investigate phase transitions. Two anomalies have been observed in temperature dependence of
specific heat for SBT nanoparticles. Under the combination with Raman spectra, it indicates that there
exists a new ferroelectric intermediate phase in the phase-transition sequence. So we can conclude
that the phase-transition sequence in SBT nanoparticles should be
ferroelectric-ferroelectric-paraelectric. Moreover, the size effect was discussed in consideration of
inner compressive stress in nanoparticles for this special transition behavior. The calculated results
show that the SBT nanoparticles keep the ferroelectricity until the particle size is decreased to 4.2 nm.
Preparation of Lipid Nanoparticles Based on Phase Behaviors of Hot Microemulsions
Authors: Xia Qiang , Lu Yang Yan , Gu Ning
Published: March 2009

The solid lipid nanoparticles (SLNs) were prepared based on the phase behaviors of hot
microemulsions which were quite different from normal microemulisons for the solid lipid as oil
phase. The pseudoternary phase diagrams for the system Brij78/deoxycholic acid sodium (DAS)/
glycerol monostearate (GMS)/water with and without the addition of retinoic acid (RA) were
obtained at 60 using home-made apparatus with temperature control. O/W and W/O region were all
found in the phase diagram. The introduction of RA has increased the O/W microemulsion region
greatly. GMS-SLN and RA-GMS-SLN were prepared by direct cooling of hot O/W microemulsion
obtained according to the phase behaviors results. The mean particle size of GMS-SLN and
RA-GMS-SLN investigated by PCS is about 10 nm. TEM images indicated that both SLNs were
spherical particles with diameter about 10 nm. PCS results showed that the particle dimension was
kept almost the same after three months, proving good stability of both SLNs. The study on the phase
behaviors of drug-loading hot microemulsions has been proved to be very significative for the
controllable preparation of SLNs which could be used as nanoscale drug delivery system (DDS) for
water insoluble drugs.
Measurement of Frictional Forces in Atomic Force Microscopy
Authors: Choi D.H. , Hwang Woon Bong
Published: March 2009

A new calibration method of frictional forces in atomic force microscopy (AFM) is
suggested. An angle conversion factor is defined using the relationship between torsional angle and
frictional signal. When the factor is measured, the slopes of the torsional angle and the frictional
signal as a function of the normal force are used to eliminate the effect of the adhesive force. Moment
balance equations on the flat surface and the top edge of a commercial step grating are used to obtain
the angle conversion factor. After the factor is obtained from an AFM system, it can be applied to all
cantilevers without additional experiments.
Tunnel Barrier Roughness Dependence of Magnetic Tunnel Junction with Synthetic Antiferromagnetic Pinned Layer
Authors: Hwang J.Y. , Kim S.S. , Rhee J.R.
Published: March 2009

MTJs of structure Si/SiO2/Ta/Ru/IrMn/CoFe/Ru/CoFe/Al-O/CoFe/NiFe/Ru with different
surface roughness of bottom electrode were prepared by sputtering, and it was investigated that the
dependence of TMR ratio and resistance-area product (RA) on plasma oxidation time, thickness and
surface roughness of tunnel barrier, and the tunneling characteristics of junction devices through I-V
curves. To get resistance of below RA 10 kΩμm2, oxidation time of 10 s for 8 Å thick Al layer was
required. In this case, thickness of Al2O3 barrier layer was 12.5 ~ 14 Å. For the 13 Å thick Al2O3
tunnel barrier, TMR ratio of optimized MTJ with uniform tunnel barrier was about 45% at bias
voltage of 100 mV. Also the barrier height and the barrier width fitted to Simmon's relation were 12.3
Å and 3.07 eV, respectively, and these values agreed with that of MTJ within error range. The I-V
curve and TMR ratio versus bias voltage curve of MTJ with rough tunnel barrier were linear and
asymmetric, respectively, but in case of MTJ with uniform tunnel barrier, these curves were
non-linear and symmetric, respectively. It was confirmed that the smooth surface of bottom electrode
was a basic requirement for MTJ.
Characterization of Solid Tin Target for Gas Discharges Produced EUV Plasmas
Authors: Zhang C.H. , Katsuki S. , Shi J.G. , Horita H. , Namihira T. , Akiyama H.
Published: March 2009

In the development of our Z-pinch plasma EUV source, xenon (Xe) is used for the
background gas discharges, and a solid tin (Sn) rod is used as target material due to its potential of
high convention efficiency (CE) from input electric energy to EUV radiation [1, 2]. The Z-pinch
plasma was driven by pulsed current with amplitude of 30 kA and pulse duration of 110 ns. Pinhole
imaging, EUV spectrograph and in-band EUV energy monitor were used to characterize the EUV
emission from the Z-pinch discharge. The experimental analyses have demonstrated the CE was as
high as 3% [3].
Synthesis of Disarrayed and Arrayed ZnO Nanowires by Physical Evaporation Deposition Approach without Catalysts
Authors: Wang L.S. , Zhang X.Z. , Zhao S.Q.
Published: March 2009

Large-scaled ZnO nanowires have been successfully synthesized by heating and
evaporating zinc powders directly without the assistance of any catalysts or additives. We acquired
disarrayed and arrayed ZnO nanowires respectively on Si(100) substrates and c-oriented ZnO thin
film. The disarrayed ZnO nanowires are about 40nm in diameter and 10μm in length, evenly and
randomly distributed on the substrate; while the arrayed nanowires are about 60nm in diameter and
3-4μm in length, well aligned along the normal direction of the substrate. XRD and TEM results
reveal that in both kinds of the products, most of the synthesized ZnO nanowires are single crystalline
in a hexagonal structure and grow along the [001] direction. During the growth process of arrayed
ZnO nanowires, the c-oriented ZnO thin film control the growth direction. Photoluminescence
spectrums were measured showing that both of the disarrayed and arrayed ZnO nanowires have a
strong ultraviolet emission around 380nm. Such results suggest the synthesized ZnO nanowires,
especially arrayed nanowires can be applied to excellent optoelectronic devices.
Influence of the Angular Light Scattering Measurement Uncertainly on the Particle-Size Distribution
Authors: Martínez J.A. , Hernández M.P.
Published: March 2009

The determination of the spherical particle-sizes in colloidal suspension by Angular Light
Scattering presents a lot of advantages, i.e.: the relative simplicity of the experimental installations,
and its non-destructive character.
The intensity of the scattered light is related with the radius of a particle by Mie Theory. However,
the dynamic characteristic of the measurements establish a variations of the scattered intensity with
the time which it has not considered.
In the case of the particle suspended in water, the intensity of the scattered light measured in each
angle θ is the superposition of the scattered intensity for each particle. In consequence, the intensity
of the light scattered will be related with a particle-size distribution function, that in this work is
assumed as a δ function.
Then, the dependence of the scattered intensity with time is studied evaluating the variation of the
center point of δ function with time taking account to the standard deviation of angular scattered
intensity.
The accuracy of the method is evaluated throw the deviation of the particle-size distribution taking
in to account the standard deviation of the angular intensity scattered by calibrated particles of latex.
A correct evaluation of the dynamic method is realized in terms of the static approach.
Synthesis and Intrinsic Stress of Ti-Containing Carbon Nitride Nanocomposite Films
Authors: Xu P. , Li J.J. , Gu Chang Zhi
Published: March 2009

Titanium containing carbon nitride (CNx) films are prepared by radio frequency magnetron
sputtering method. The evolution of intrinsic stress within the nanocomposite films is monitored
during growth by using an in situ bending-plate method. The effect of Ti-containing concentration on
intrinsic stress is investigated. XRD data shows that TiN nanocrystals are synthesized to embed into
the CNx matrix. The film intrinsic stress depends obviously on the content of Ti. We suggest that
grain boundary effect is responsible to the intrinsic stress variation as a function of the content of Ti.
C-Doped TiO2 with Visible Light Photocatalytic Activity
Authors: Dong C.X. , Xian A.P. , Han En-Hou , Shang J.K.
Published: March 2009

Carbon doped titanium dioxide photocatalysts have been synthesized by a precipitation method.
Anatase TiO2 was obtained when the precipitate was heat-treated at 400°C when rutile phase
appeared at 600°C. The absorption spectra of the powders showed strong absorption in visible
region. For the sample calcined at 400 °C , the absorption extended up to 750nm. X-ray
photoelectron spectrum (XPS) confirmed that carbon atoms were incorporated into the TiO2 crystal
lattice. Photodegradation experiments showed that the powders had visible-light degradation
activity.
Studies of Photocatalytic Degradation of Trace-Level MC-LR in Water on Thin Film of Titanium Dioxide
Authors: Feng X.G. , Rong F. , Wei Tao , Yuan Chun Wei
Published: March 2009

MCs are produced by cyanobacteria and cause concerns in potable water
due to toxicity. Conventional treatments are poor at removing MCs. In the present
study, the photocatalytic degradation of MC-LR was conducted using nano-TiO2 thin
film, prepared by sol-gel and dip-coating method, with UV 365nm irradiation.
According to analysis results from solid-phase extraction combined with HPLC
method, the trace-level MC-LR is easily to be removed by photocatalytic system. The
degradation efficiency of MC-LR is influenced by the pH conditions, initial
concentration due to adsorption of MC-LR on TiO2 thin film. The maximum initial
rate of photocatalytic degradation occurs at pH 4 and over 95% of 20μg/L MC-LR is
decomposed within 120min. The kinetic equations and parameters revealed that
degradation reaction of trace level MC-LR, which depicted by pseudo first order
kinetics process in appearance, was in accordance with Langmuir-Hinshelwood
kinetics model well, the corresponding rate constant k and Langmuir adsorption
constant K were determined to be 19.72μg/l·min-1 and 6.57×10-4l/μg, respectively.
Synthesis and Dielectric Property of Perovskite-Type LaMnO3 Nanoparticle
Authors: Sun Jie , Zhang Zhen Hua , Cao Xiao Hui
Published: March 2009

The perovskite-type nanocrystal LaMnO3 was prepared using sol-gel auto-combustion method with citric acid as the
chelating agent. Some analytical methods consisted of FT-IR, XRD, TEM and wave-guide method were used to characterize the gel and
the final products. The metal ions coordination compound, obtained from nitrate and citrate, underwent an auto-combustion process and
voluminous ashes formed when calcining the complex in the air. From the result of the dielectric properity. It was shown that the
dielectric coefficient curves and dielectric loss curve of LaMnO3 nanocrystals were smooth in the range of 8-11MHz. The dielectric loss
can be obversed obviously in the measured range.
Ce Basic Hydroxycarbonate Complexe as Precursor for Mesoporous Ceria: Synthesis and Characterization
Authors: Yang D. , Wen Ming Fen , Song Ch.L. , Chen Jian , Gu Yong Wan
Published: March 2009

Herein mesoporous CeO2 with high thermal stability was synthesized via a new
hydroxycarbonates based hydrothermal threatment approach in present of
hexadecyltrimethylammonium bromide (CTAB). IR and XRD prove the coexistence of
hydroxycarbonate cerium and CTAB in precursors. TEM micrographs show that non-ordered pore
structure is formed in the product, and average particle size of 20 nm is obtained even after calcined at
1173 K. BET results exhibit that the pore structure is stable when the calcination temperature is
below 923 K. However, While calcinated at 1173 K, the average particle size is 20 nm, the BET
surface area and pore volume can remain as high as 31.07 m2/g and 0.21 cm3 g-1.
Tribological and Mechanical Properties of Carbon Nanofiber-Filled PTFE Composites
Authors: Shi Yi Jun , Feng Xin , Diao X.S. , Wang Huai Yuan , Lu Xiao Hua
Published: March 2009

The tribological and mechanical properties of carbon nanofiber (CNF)-filled
polytetrafluoroethylene (PTFE) composites with different filler proportions were
studied. The worn surfaces of PTFE and carbon nanofiber/PTFE (CNF/PTFE)
composites were then examined with scanning electron microscope (SEM). The
results show the friction properties of CNF/PTFE composites decreased then
increased with the increasing content of CNFs, while the anti-wear properties of
CNF/PTFE composites were much higher than that of pure PTFE. The best anti-wear
property was obtained with the composite containing 2 wt.% CNFs. The wear volume
loss of the composite contained 2 wt.% CNFs was only about 1/700 that of PTFE
without CNFs under the condition of 150N and 1.4m/s. Meanwhile, the results also
indicate that the mechanical properties of CNF/PTFE composites increased then
decreased with the increasing filler concentration, and the composite contained 1
wt.% CNFs has the best mechanical properties. Compare to pure PTFE, the tensile
strength and the elongation of CNF/PTFE composites increased about 20% and 70%
respectively when the filler content is 1 wt.%. It was seen from the worn surfaces
micrographs of PTFE and CNF/PTFE composites that CNFs greatly reduce the
adhesive wear of PTFE.
Coherency and Surface Stress Effects on Phase Stability of Isolated Nanoparticles
Authors: Huh Joo Youl , Lee Heon , Johnson William C.
Published: March 2009

The coherent phase equilibria of binary nanoparticles, in which three phases can be formed,
were examined by accounting for the particle size effect engendered by the surface stress. Considering
the system geometry exhibiting radial symmetry, coherent phase diagrams could be constructed for
different particle sizes. The phase diagrams exhibited several characteristics of phase equilibria
unique to coherent systems. It was found that a positive surface stress results in a radial compressive
stress in the particle that is inversely proportional to the particle radius, thereby increasingly
stabilizing the phase having a lower molar volume as the particle size decreases.
Nano-Composite Materials Studied by CTEM and STEM
Authors: Wang Jian Bo , Li Lu Ying , Liu Zhe , Wang Ren Hui
Published: March 2009

Various techniques in conventional transmission electron microscopy (CTEM) and
scanning transmission electron microscopy (STEM) are applied to characterize comprehensively the
microstructures of the nano-composite materials, including Cu2O quantum dots deposited on
multiwall carbon nanotubes (CNTs) and Fe particles encapsulated in carbon nanohorns (CNHs) as
two studying cases.
Dependence of Thermal-Cycling-Induced Deformation on Passivation Morphology in Plastic-Encapsulated Microelectronic Devices
Authors: Lee Seong Min
Published: March 2009

This study examines how the increased density of passivated metallic conductor lines
caused by large circuit integration in semiconductor devices influence their reliability during a
thermal-cycling test. It was found that a decrease in the size of the trench-shaped space formed
between two passivated conductor lines reduces the thermal cycling reliability of the passivation
layer (i.e. in this case, consisting of Si3N4). The increased depth of the trenches results in more
severe deformation in the surrounding area and brittle fractures in the passivation layer. In particular,
the present work indicates that as the ratio of trench depth to trench width increases from 1:1 to 5:1,
the number of failures caused by thermal cycling increases up to 2-fold. Numerical calculation also
shows that the region of maximum stress is found at the corner of the interface between the flat
passivation layer (i.e., the surface without any trenches) and its underlying metallic conductor. In
cases where trenches exist, however, the region of maximum stress shifts from the interface corner
to the trench corner. Furthermore, the level of the maximum stress was calculated to be lower at the
interface corner than the trench corner, by 11%.
The Effect of ZnO:Al Sputtering Condition on a-Si:H / Si Wafer Heterojunction Solar Cells
Authors: Kim Sang Kyun , Lee Jung Chul , Dutta Viresh , Park Sung Ju , Yoon Kyung Hoon
Published: March 2009

A-Si:H/Si wafer heterojunction solar cells with different ZnO:Al sputtering conditions
were fabricated and the effects of sputtering conditions on device performance were evaluated.
Various sputter condition(substrate temperature RT~200’C, working pressure 0.5mTorr~15mTorr,
thickness 60~100nm) were tested and optimized as 130’C, 0.5mTorr, 80nm by measuring reflectance
and sheet resistance of ZnO:Al layer on corning glass.
However, when optimal ZnO:Al condition was applied to solar cells, series resistance was high
which led to device efficiency ~10%. Dark I-V curves of with and w/o ZnO layer showed large
difference, which means there is a kind of barrier to current flow between ZnO:Al and a-Si:H layer.
Modified condition with double layer scheme was applied and lower series resistance and device
efficiency above 12% could be reached. The improvement may be due to either suppression of Si
oxide formation or less defect formation by impinging atoms.
Characteristics of Lithium Polysilicate Electrolyte Synthesized by Sol-Gel Processing
Authors: Jin Bong Soo , Min Bok Ki , Doh Chil Hoon
Published: March 2009

To find out suitable Si surface treatment and heat treatment conditions, acid treatment of Si
wafer was done for lithium polysilicate electrolyte coating on Si wafer. In case of HCl treatment, the
wet angle of a sample is 30o, which is the smallest wet angle of other acid in this experiment. Acid
treatment time is 10 min, which is no more change of wet angle. Lithium polysilicate electrolyte was
synthesized by hydrolysis and condensation of lithium silicate solution using perchloric acid. Thermal
analysis of lithium polysilicate electrolyte shows the weight loss of ~23 % between 400 and 500 ,
which is due to the decomposition of LiClO4. The XRD patterns of the obtained lithium polysilicate
electrolyte also show the decrement of LiClO4 peak at 400 . The optimum heat treatment
temperature is below 400 , which is the suitable answer for lithium polysilicate electrolyte.
Electrochemical Behaviors of PtRu/CNTs Catalysts Prepared by Pulse Potential Plating Methods
Authors: Kim Seok , Kwon Yun Hee , Jung Yongju , Park Soo Jin
Published: March 2009

In this work, PtRu/CNTs catalysts were prepared by pulse potential plating
methods. The particle size and loading level of catalysts were measured by changing the
plating time and pulse interval of pulse potential plating method. Electrochemical activities of
PtRu/CNTs catalysts were measured by cyclic voltammetry (CV). PtRu/CNTs catalysts
showed an increased the electrochemical activity of methanol oxidation up to 24min and a
slightly decreased activity over 24min. The electrochemical activity was increased with
increasing of the pulse interval. Consequently, it was found that optimal plating time was
24min and optimal pulse interval was 0.5s for electrochemical activity of PtRu/CNTs
catalysts.
Performance of Tin Oxide/Graphite Composite Anode for Lithium Ion Battery
Authors: Jin Wen Jie , Park Sei Min , Hong Ik Pyo , Lee Seong Young , Kim Myung Soo
Published: March 2009

The graphite particles with average size of 15 μm were used as the anode base materials for
lithium ion battery. Tin oxide was incorporated into graphite particles by a precipitation method. As
SnO2 content increased from 0 to 80 wt%, the initial discharge capacities of SnO2/graphite composite
electrodes raised from 357 to 688 mAh/g, approaching to their theoretical capacities. The composite
electrodes exhibited plateau characteristics of SnO2 at 0.85 1 V range in the charge voltage-capacity
curves of the first cycle. Increased reversible capacity of the composites suggested that lithium ion
could be stored in the both lattices of tin and graphite. It was demonstrated by XRD that the tin metal
decomposed from tin oxide in the first cycle of charge played a leading role of charge/discharge
thereafter.
A Study on the Effect of Structure and P-Doping of Si Thin Film as an Anode for Lithium Rechargeable Batteries
Authors: Song Jin O , Shim Heung Taek , Byun Dong Jin , Lee Joong Kee
Published: March 2009

Effects of substrate temperature and phosphor doping on electrochemical characteristics of
the silicon film anode were investigated. The silicon thin films were synthesized directly on copper
foil by radio-frequency capacitively coupled plasma-enhanced chemical-vapor deposition (r.f.-CVD).
The cyclability of the silicon anode greatly depends on the surface morphology and surface resistivity.
The silicon film anodes which have granular structure and high conductivity showed higher cyclabilty
than those of planer and low conductivity, respectively.
Conductive Sol-Gel Hybrid Materials for Novel Cofactor Regeneration in Biocatalysis
Authors: Won Kee Hoon , Siu Eulaia , Park Chan Beum
Published: March 2009

The electrochemical recycling of cofactors during enzymatic biocatalysis has long been
acknowledged as a potentially powerful technology in fine chemical synthesis. Major obstacle for this
approach is that cofactors only in the immediate vicinity of the electrode surface are productive. This
problem further causes high overpotential at electrode surfaces leading to undesired side reactions
producing enzymatically-inactive dimer and isomer of cofactor. So far, several attempts had been
made to address these problems by focusing on surface modifications, which explored to retain the
enzyme and/or cofactor close to the working electrode including electrode deposition and membranes
surrounding the electrode. In this work, we demonstrate a new concept of cofactor regeneration by
using ‘electronically-conductive’ sol-gel hybrid materials. When conductive hybrid gels were added
to the reaction medium, we found that cofactor could be efficiently recycled throughout the whole
reactor system leading to high yield of product, which was unattainable with conventional
technologies.
Impregnation of Eicosane into Polyester Fiber Using Supercritical Carbon Dioxide
Authors: Kim Tae Won , Kim Jung Teag , Park Chan Young , Kim Chang Hun , Ju Chang Sik
Published: March 2009

Supercritical impregnation of eicosane into polyester fiber was experimentally examined.
Polyester fiber was bound on the cylindrical stainless steel net inside high pressure cylinder and was
impregnated with supercritical eicosane solution. After an hour under supercritical condition, the
system was expanded to atmospheric pressure and impregnated polyester fiber was obtained.
Eicosane was successfully impregnated into the polyester fiber even at temperature below it’s glass
transition(Tg), and the impregnated fiber showed high energy storage and release capacity around the
melting point of eicosane.
Structures and Physical Properties of Multi-Walled Carbon Nanotube-Filled PVDF Thermoplastic Composites
Authors: Chae Dong Wook , Nam Young Wan , Wang Seung Sangh , Hong S.M.
Published: March 2009

Poly(vinylidene fluoride) (PVDF) / multi-walled carbon nanotube (MWNT) thermoplastic
composites was melt compounded in an internal mixer. The percolation level for this system in
electrical conductivity clearly occured between 2 and 2.5 wt%. PVDF/MWNT thermoplastic
composites exhibited an increased crystallization temperature with the loading level, at 10 wt%
loading by ca. 6. In addition, they presented a shoulder posterior to the main melting peak and an
increased endpoint of the peak. In the Wide Angle X-ray Diffraction (WAXD) patterns, the
incorporation of MWNT produced a larger shoulder at 2θ =20.7° with increasing the loading level,
corresponding to the β-form crystal of PVDF.
Preparation and Characterization of Multiwalled Carbon Nanotube/Poly(ε-Caprolactone) Composites via In Situ Polymerization
Authors: Kim Hun Sik , Park Byung Hyun , Yoon Jin San , Jin Hyoung Joon
Published: March 2009

Poly(ε-caprolactone)/multiwalled carbon nanotube (PCL/MWCNT) composites with
different MWCNT contents were successfully prepared by in situ bulk polymerization, which could
make them good competitors for commodity materials such as general purpose plastics, while
allowing them to completely retain their biodegradability. The mechanical properties of the
PCL/MWCNT composites were effectively increased due to the incorporation of the MWCNTs. The
composites were characterized using scanning electron microscopy, in order to obtain information on
the dispersion of the MWCNTs in the polymeric matrix. In the case where 0.5 wt% of MWCNTs were
dispersed in the matrix, the strength and modulus of the composite increased by 23% and 71%,
respectively. In addition, the dispersion of the MWCNTs in the PCL matrix resulted in a substantial
decrease in the electrical resistivity of the composites being observed as the MWCNTs loading was
increased from 0 wt% to 0.5 wt%.
Effect Of Al2O3 Particle Size on Compressive Behavior of Al Composites
Authors: Seo Young Ik , Min Kyung Ho , Lee Young Jung , Lee Kyu Hwan , Sekino Tohru , Kim Young Do
Published: March 2009

Compressive behavior of 7xxx series Al metal matrix composite (MMC) powders with
different ceramic contents and different particle size were investigated. As a starting powder of the
experiments, ceramic contents of each starting powder were 5 and 10 wt.% and ceramic particle
size of starting powder were 20 and 100 ㎛, respectively. And 7xxx Al blended powder was used
for comparison. The powders were uniaxially cold-compacted using cylindrical die with a
compacting pressure 250 MPa and sintered at 620oC in a dry N2 atmosphere for 60 min with heating
rate of 20oC/min. In case of heat treatment condition, sintered parts were solution treated at 475oC
and aged at 175oC. To reveal the effect of Al2O3 particle content and particle size on the mechanical
properties of composites, compression test were conducted with constant strain rate of 1×10-3/s
using sub-size cylindrical samples of 9 mm diameter. Compression test was performed 5 times and
its average value was used. Then fractography analysis was conducted using scanning electron
microscope.
Large Area Synthesis of 1-D ZnO Nanostructure Arrays on Zn Substrate via Solvothermal Process
Authors: Park Je Hyeong , Choi Hong Goo , Kim Jong Ho , Kim Do Kyung
Published: March 2009

Large areas of one-dimensional ZnO nanostructures (nanorods and nanowires) were
prepared by simple solvothermal method. The synthesis involves a template-less and surfactant free
aqueous methods. In this study, Zn metal sheet was used as both Zn2+ ion source for the growth of
ZnO nano-structures and substrate for oxide film. The mixed solvent of 1-propanol with water was
used as solvents for nanorods and ethylene glycol with water was for nanowires. The solvothermal
treatment of a zinc metal plate with the solvents at the temperature of 125 oC for 10 hours resulted in
the 1-D ZnO nanostructures, which were grown on the Zn metal sheet. The synthesized ZnO was well
aligned on whole area of substrate and the nanorods were 150 nm in diameter and 3 μm in lengths,
respectively.
Characteristics of Gas Sensors Based on Single-Walled Carbon Nanotube Bundles Treated by Acid Stirring
Authors: Nguyen Hong Quang , Zhang Shao Lin , Rue Gi Hong , Huh Jeung Soo
Published: March 2009

The paper presents the effect of acid treatment on the structure of single-walled carbon
nanotube (SWNT) bundles and on the characteristics of SWNT-based gas sensors. The commercial
SWNT powder was treated with a mixture of concentrated H2SO4:HNO3 (3:1 in volume) before used
to fabricate sensors for ammonia (NH3) detection at room temperature. The Transmission Electron
Microscopy (TEM) and Scanning Electron Microscopy (SEM) images indicated that the acid
treatment not only removed most of catalytic particles from the SWNT bundles, but also caused
SWNT bundles to be fragile. The fracture of the SWNT facilitated for gas molecules to adsorb in the
SWNT sites, leading to an enhancement in sensitivity of the sensors. Upon exposing to 50 ppm NH3
in 450 sccm of nitrogen flowing rate at room temperature, the resistance of the 2-h-stirred sensors
increased to 38% compared to 22% of the 1-h-stirred sensor. The recovery of the SWNT sensor was
also accelerated owing to the treatment. These findings opened a new direction to improve the
characteristics of SWNT-based gas sensors.
Synthesis of High Concentration Cuprous Oxide Nanoparticles by Modified Polyol Process
Authors: Shim In Keun , Lee Young Il , Lee Kwi Jong , Joung Jae Woo
Published: March 2009

Cuprous oxide nanoparticles at high concentration (up to 0.3M) were successfully
synthesized by modified polyol process. The redispersion stability could be controlled by optimizing
various conditions like polymer concentration, temperature, reductant, and catalyst. Reductant and
catalyst play a crucial rule in redispersion of cuprous nanoparticles. Under poor conditions, particles
grow to larger sizes due to aggregation of nanoparticles. This modified polyol process allows
monodispersed cuprous oxide to be obtained on gram scale in a single reaction and make possible a
high synthetic yield of more than 80%.
Chemically Driven Polyacrylonitrile Fibers as a Linear Actuator
Authors: Lee Se Jong , Lee Deuk Yong , Song Yo Seung , Cho Nam Ihn
Published: March 2009

A pH sensitive polyacrylonitrile (PAN) fiber, exhibiting soft actuation as a linear actuator,
is prepared by electrospinning to investigate the optimum experimental condition of the as-spun
fibers and the effect of pH variation on length change of PAN gel fiber. Unbeaded smooth and
continuous PAN nanofibers with diameter of ~700 nm are obtained for the 10 wt% PAN fibers at a
flow rate of 0.5 mL/h and an electric field of 0.875 kV/cm, suggesting that the value of viscosity is
the most significant on the fiber morphology. Diameter and volume changes of PAN filaments are
observed as greater than 100% and greater than 720%, respectively for pH activated systems. A
typical hysteresis loop is observed for the length change (~38%) of PAN gels with respect to pH
variation.
Effect of Surfactant on the Morphology of Silver Nanoparticles
Authors: Park Keun Ju , Seo Dong Seok , Jang Woo Yang , Lee Jong Kook
Published: March 2009

Nano-sized silver particles are considered to apply a silver paste for electrode because of its
high conductivity on sintering at low temperature. In this study, silver nanoparticles as seeds were
prepared by chemical reduction method with capping agent. Silver particles were prepared using SDS
(Sodium dodecyl sulfate) as a surfactant and silver nanoparticles as seeds and reacted with ascorbic
acid as a reduction agent. The silver seeds with 10-20 nm in size with uniform distribution were
formed and the size and shape of silver particles were strongly dependent on the concentration of
surfactant.
Preparation and Characterization of CdSe Nanoparticles Synthesized Using the Ultrasonic Irradiation
Authors: Sung Myoung Seok , Lee Yoon Bok , Kim Yong Jin , Kim Yang Do
Published: March 2009

Cadmium selenide(CdSe) nanoparticles were prepared in the aqueous solution containing
isopropyl alcohol by the ultrasonic irradiation at room temperature. The cadmium chloride (CdCl2)
and sodium selenosulfate (Na2SeSO3) were used as the cadmium and selenium source, respectively.
X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron
microscopy (TEM), UV-Vis absorption spectra and PL spectra were used to characterize the CdSe
nanoparticles. XRD analysis revealed the formation of cubic structure CdSe. TEM images showed
aggregated CdSe nanoparticles with the size of nanometer scale. Average size of CdSe nanoparticles
were about 3.9, 5.0 and 5.1nm with sonication time of 6, 30 and 40 minutes, respectively. The
surface emission became less intensive and shifted to red with increasing irradiation time. This
paper presents the effects of ultrasonic on the formation of CdSe nanoparticles and its
characteristics.
The Novel Methods for Preparing Antibacterial Fabric Composites Containing Nano-Material
Authors: Wu Te Hsing , Tai Yi Der , Shen Lie Hang
Published: March 2009

This paper is to develop an antibacterial fabric by mainly radiation grafting technique.
Because a fabric should be soft and comfortable, so antibacterial materials need to be very
small in size to graft on the fabric. This work used nanosized antibacterial solution or powder,
Nylon and PET fibers, as starting materials to prepare antibacterial fabric products.
Two radiation synthetic processes were used in the paper, 1. the nanosized silica powder
or solution containing silver (named Ag/SiO2) was introduced to Nylon or PET (Polyethylene
terephthalates) fabric by means ofγ-ray irradiation method. 2. the nanosized silver particles
in solution were reduced and deposited on the surface of fabric used by radiation reduction
technique. The microscope TEM & SEM (transmission and scanning electron microscope) and
ICP(Induced coupled plasma)…etc were utilized to analyze the characteristics of antibacterial
fiber products. In addition, these antibacterial fibre products prepared by radiation reduction
method were also subjected to test the antibacterial effect.The results showed that silver-Nylon
and silver-PET antibacterial fiber have good antibacterial effects against Staphylococcus aureus
, especially the Ag-PET fiber having the better effect than Ag-Nylon fiber.
A New Insight into the Mechanistic Study on Synthesis of Silica Nanospheres
Authors: Yun Dong Shin , Kim Hyun Jung , Shin Hyun Chang , Narayanan Venkatathri , Yoo Jung Whan , Lee Seong Ho , Lee Dong Jin , Kim Nam Hoon
Published: March 2009

The physicochemical characteristics (SEM, N2 adsorption, FT-IR, MASNMR) of samples
from kinetics (10 min, 20 min, 30 min, 1 h and 3h) of hydrolysis of tetraethyl orthosilicate (TEOS)
gives new insight into the synthesis of nanosphere. The particle sizes are increased with time,
however, the surface areas decreased. FT-IR investigation reveals the presence of high intensed
silanol groups of 960 cm-1 at 10 min, which reduced on progress of the reaction time. This suggests
the partial hydrolysis and condensation of alkoxy groups in TEOS. 29Si MASNMR analysis shows the
presence three different silica species(Q4, Q3 and Q2) in 10 and 20 min samples. The intensity of Q2
species decreases with time and other species concentration were increased.
The Effect of DC Bias Voltage on the Structural and Optical Properties of Hydrogenated Nanocrystalline Si Thin Films
Authors: Shim Jae Hyun , Cho Nam Hee
Published: March 2009

Amorphous and nanocrystalline Si films were prepared by plasma enhanced chemical
vapor deposition (PECVD). The films were deposited with a RF power of 100 W, while substrates
were under DC biases varying from 0 to -600 V. The size as well as the concentration of Si
nanocrystallites increased with raising the DC bias; the PL emission wavelength was shifted from 400
to 750 nm. A model for the nanostructural variation in the nc-Si:H films was suggested to describe the
change in the size and concentration of the nanocrystallites as well as the amorphous matrix
depending on the DC bias conditions.