bluuebunny/crossref_metadata_2025 huggingface dataset:
Contact Fatigue Strength and Wear Characteristics of Plasma-Carburized Rollers
Authors: Koide Takao , Tsubokura Koji , Nakatani Masayuki , Miyachika Kouitsu , Yakabe Masaki , Namba Chiaki , Oda Satoshi
Published: March 2009

In the plasma-carburizing method, the detrimental grain boundary oxides in the surface of
the materials and sooting problems are eliminated and the high carbon content near the surface is
easily achieved. This paper describes a study on the contact fatigue strength and wear characteristics
of plasma-carburized rollers. Test rollers made of super-carburizing steel MAC14 and conventional
carburizing steel SCM415 were plasma-super-carburized under different carburizing conditions. The
contact fatigue tests were carried out for these plasma-super-carburized rollers. The effects of case
depths on the contact fatigue strength of these rollers were determined. The effect of shot-peening on
the contact fatigue strength was also examined by carrying out contact fatigue tests for shot-peened
rollers. The wear tests were also carried out and then the wear characteristics of test rollers were
determined. These test results for plasma-super-carburized rollers were compared with the results for
gas-super- or gas-eutectoid-carburized rollers.
Manufacturing and Plasma Electrolytic Oxide Coatings on the Thin-Wall Aluminum Notebook PC Case
Authors: Kang Chang Seog , Oh Ik Hyun , Cho Jae Ik , Lee Jae Seol , Son Hyeon Taek , Bae Jung Chan , Kim Young Chan , Hong Sung Kil
Published: March 2009

The silicon-based aluminum casting alloy and 2 different types of gate designs were used
to investigate experimentally the fabrication feasibility of sound thin-wall case casting by diecasting
process. While split type gate design had no defect, tangential type gate design resulted in
cracks in the all obtained specimens. Electrolytic Oxide (PEO) coating was performed as a surface
treatment process. Before the PEO coating treatments some die cast specimens were heat treated at
the temperature of 323K and N2 atmosphere for 1hr to evaluate the effect of heat treatment. The
result showed that hardness was improved after PEO coating, however, the effect of heat treatment
was not significant.
Effects of Annealing Treatment on Microstructure and Thermoelectric Properties of Ba8Al16Si30
Authors: Lee Jung Il , Park Jong Bum , You Sin Wook , Lee Joo Ho , Kim Il Ho , Jang Kyung Wook , Ur Soon Chul
Published: March 2009

Clathrate Ba8Al16Si30 was produced by arc melting and annealing effects on the microstructure and thermoelectric properties were investigated. The phase transformation behavior of arc-melted Ba8Al16Si30 was examined by thermogravimetric analysis, differential scanning calorimetry, hardness test, X-ray diffraction and scanning electron microscope analyses. Isothermal annealing was carried out to induce the transformation to a thermoelectric phase at 500°C to 700°C for 5 hrs. Thermoelectric properties in the temperature range between 300K and 600K were measured and evaluated. Electrical conductivity was decreased and Seebeck coefficient was increased with increasing isothermal annealing temperature. The arc-melted and the isothermal annealed specimens represented n-type conduction at temperatures examined, and they showed reliable thermoelectric behaviors.
Study On Nano-Structured SnO2-23wt%TiO2-21wt%RuO2 Coated Titanium Anode
Authors: Wang Xin , Tang Dian , Zhou Jing En
Published: March 2009

Sn is one of the most important elements for the Cl2-evolving anode coatings, but it always used as a minor additive. In this paper, an Sn-based ternary oxide coating with its composition of SnO2-23wt%TiO2-21wt%RuO2 was prepared by a sol-gel technique through etching, painting, sintering and annealing. The differential thermal analysis (DTA) shows that the crystallization behavior of the ternary xerogel is more similar to that of pure xerogels SnO2. X-rays diffraction (XRD) indicates that the coating is composed of rutile phase (Sn,Ti,Ru)O2. Any other undesired phases, for example, anatase TiO2 and metallic ruthenium phases are not found in the coatings. The microstructure and the morphologies were studied by a transmission electron microscope (TEM) and a scanning electron microscope (SEM). The results of energy dispersive spectrometer (EDS) indicate Sn content in the coatings remain at high level and coincident with the nominal composition. The grain sizes in the coatings are around 4 nm. The voltage of Cl2-evolution and O2-evolution shows the ternary coating has good electrochemical properties.
Microstructural Characterization of the Emulsified Cu47Ti33Zr11Ni6Sn2Si1 Alloy Powder
Authors: Kang Ho Suk , Kang Hee Sam , Yoon Woo Young
Published: March 2009

Phase selection and microstructural morphology change of the Cu47Ti33Zr11Ni6Sn2Si1
alloy were investigated through the droplet emulsion technique(DET). The emulsified
Cu47Ti33Zr11Ni6Sn2Sil alloy powders showed several different microstructures depending on the
amount of undercooling. The amount of undercooling of the powders was monitored by differential
thermal analysis and was matched with the microstructures. The phase transition of
Cu47Ti33Zr11Ni6Sn2Sil alloy powders according to the increase of undercooling proceeds by the
process Cu4Ti3 +CuTi +Cu2Ti +Cu51Zr14 → Cu4Ti3 + CuTi + Cu2Ti + Cu51Zr14 + CuTi2 → Cu2Ti +
Cu51Zr14 + CuTi2 → Cu51Zr14 +CuTi2. Specifically, the morphology and scale of the CuTi2 phase
were examined by SEM observation, and area fraction measurement using an image analyzer,
transmission electron microscopy studies, and microhardness tests showed that the amorphous
phase could be synthesized by DET. A microstructure selection map of Cu47Ti33Zr11Ni6Sn2Sil alloy
powders for tailored solidification was also suggested.
Nanostructure Formation of Amorphous Al-Ni-Mm Alloy
Authors: Hong Soon Jik , Lee Min Ku , Rhee Chang Kyu
Published: March 2009

Nanostructure formation of fully amorphous Al86Ni9Mm5 alloys in both as solidified
amorphous and annealed nanocomposite conditions was investigated using XRD, DSC, and TEM.
The exothermic reaction peak of DSC is associated with the crystallization of fcc-Al, Al3Ni, and
A111Ce3 phase. The microstructure of annealed specimen at 250 oC consists of a random distribution
of fine nanocrystalline fcc-Al crystals embedded in the amorphous matrix. During primary
crystallization, partitioning of the solute atoms takes place at the interface, resulting in an increase of
solute atoms in the amorphous and interdendritic resign. The final microstructure shows a
homogeneous distribution of intermetallic compounds embedded in the Al matrix. The hardening
effect of nanostructured specimens annealed at 250 oC is attributed to both solute enrichment in the
amorphous matrix and formation of fcc-Al crystallites. The highest hardness of 490 Hv in this
research is obtained in the specimen heat treated at 300 oC for 20 min.
Effect of Annealing Conditions on the Microstructure and Corrosion Characteristics of Zr-xNb Alloys
Authors: Kim Hyun Gil , Jeong Yong Hwan
Published: March 2009

Most of the advanced Zr-based alloys contain Nb for improving the corrosion resistance. However, the Nb effect on the corrosion behavior of Zr alloys has not been established. For developing fuel cladding materials, it is essential to investigate the effect of the Nb-content and annealing conditions after beta quenching on the microstructure and the corrosion of Zr-xNb alloys. In this study, a systematic investigation to obtain the optimized annealing condition and Nb content were performed for Zr-xNb alloys (x = 0.1~2.0 wt.%). The corrosion resistance of 0.1 and 0.2 wt.% Nb alloys where Nb existed in an equilibrium soluble state in the matrix was excellent in the quenched and annealed conditions. For the high Nb-containing alloys, the corrosion rates were very sensitive to the annealing condition, and it took about 50 hours at 570 to reach the corrosion rates comparable to those of the low Nb wt.% alloys. The corrosion resistance was closely related to the stabilization of the tetragonal ZrO2 and the columnar oxide structure when the Nb concentration in the matrix was reduced to the equilibrium soluble limit.
Adsorption of Carboxymethylated Polyethyleneimine (CM-PEI) on a Microporous Activated Carbon
Authors: Yeon Jei Won , Jung Y. , Kim Won Ho
Published: March 2009

We applied a polymer-based surface modification technique to the surface treatment of a microporous activated carbon. We used a new chelating polymer, carboxymethylated polyethyleneimine (CM-PEI), as a functional polymer to modify the carbon surface. In this study, we examined the adsorption phenomena of the CM-PEI on an activated carbon with a nanopore less than 2 nm in diameter and evaluated the adsorption mechanism using three kinds of models; Langmuir, Freundlich, and Redlich-Peterson isotherm. It was found that the adsorption of CM-PEI on the F400 follows the Freundlich isotherm model. Furthermore, desorption experiments of the CM-PEI were carried out to examine the stability of the CM-PEI adsorption on the F400 and to estimate the applicability of the CM-PEI-coated F400 to the adsorbents. It was observed that most of the CM-PEI remains on the F400 for 7 days in the pH range of 3 to 7. Especially, the adsorption amount of CM-PEI on the F400 did not change after 3 days at the pH range of 5 to 7, indicating that the CM-PEI strongly adheres to the F400.
Ion Conductivity of Polymer Electrolytes Based on PEO Containing Li Salt and Additive Salt
Authors: Kim Seok , Hwang Eun Ju , Park Soo Jin , Kim Hyung Il
Published: March 2009

Solid type polymer electrolyte is in progress of research and development in many ways to
improve an ionic conductivity to attain 10-3 S/cm which is possibility of practical use of secondary
lithium ion battery. There are two major methods of improving ionic conductivity; either lowering Tg
of polymer or lowering the energy of ionic movement. In this work, the solid type polymer electrolyte
(SPE) composites, which were composed of poly(ethylene oxide) (PEO), ethylene carbonate (EC) as
a plasticizer, lithium salt, and 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI-PF6) as a
filler in order to improve the ion conductivity of the SPE, were prepared. The influence of EMI-PF6
contents on the ionic conductivity of the SPE composites was investigated in this work. As a result,
the ionic conductivity of the SPE was enhanced by an increase in EMI-PF6 content, and showed the
highest ionic conductivity at 40 wt.%. It was thought that there was a close correlation between the
mobility of Li+ and EMI content in a SPE composite system.
Effect of Cooling Rate on Mechanical and Electrical Properties of Cu-TiB2 by Turbulent In-Situ Mixing Process
Authors: Park J.S. , Yun J.H , Park Young Do , Park Yong Ho , Cho Kyung Mok , Park Ik Min
Published: March 2009

A copper matrix composite reinforced with in situ TiB2 nanoparticle was successfully fabricated by tubulent in-situ mixing process. The microstructure, mechanical and electrical properties of the in situ composite were investigated. The results showed that the in situ formed TiB2 particles, in which size varying from about 50nm to 200nm, exhibited a homogenous dispersion in the copper matrix. It is shown that the interface between the nanoscale particles and the matrix was clean without a transitional layer. Because of the reinforcement, the hardness and Young’s Modulus of the composite improved with increment of cooling rate. Moreover, the in situ Cu-TiB2 composite exhibited higher electrical conductivity with increasing of cooling rate.
Preparation and Characterization of PP/Organoclay Nanocomposites with Maleic-Anhydride
Authors: Lee Hyung Min , Park B.J. , Chin In Joo , Kim Hyo Kyoung , Kang Won Gu , Choi Hyoung Jin
Published: March 2009

Polypropylene (PP)/organoclay nanocomposites were prepared via a melt-mixing method
through two-step melt compounding using a co-rotating intermeshing twin screw extruder. Maleic
anhydride grafted polypropylene (PP-g-MA) was adopted during compounding as a compatibilizer.
Structural investigations via X-ray diffraction (XRD) and transmission electron microscopy (TEM)
revealed the intercalated morphology of the nanocomposites. The use of PP-g-MA led to not only
good clay dispersion but also heterogeneous intercalation. Thermal degradation of the PP
nanocomposites was studied by thermogravimetric analysis (TGA). Rheological properties of the
PP/organoclay nanocomposites were also investigated via a rotational rheometer in which linear
viscoelastic measurements were performed in oscillatory shear with small strain amplitude. Storage
(G’) and loss (G”) moduli were found to be increased at all frequencies with increasing clay contents.
Synthesis and Properties of TiO2/ZnO Core/Shell Nanomaterials
Authors: Zhang Xiao Li , Kim Young Hwan , Kang Young Soo
Published: March 2009

Core/shell structured TiO2/ZnO was synthesized in a basic aqueous solution through a simple hydrolyzing method. The powder X-ray diffraction (XRD) and transmission electron microscopy of the initial TiO2/ZnO powder showed diffraction peaks corresponding to the ZnO and TiO2 phase. The structure and thickness of ZnO shell (about 2.5 nm) coated TiO2 surface as thin layers or nanoclusters, depends upon the reactant concentration and the reaction time. The characteristics of the optical absorption were described by UV-visible absorption spectroscopy.
Various Types of Pt-Ni Binary Catalysts Supported on the Carbon Nanotubes as Cathode Catalysts for DMFC
Authors: Seo Yon Ki , Kim Yong Hwan , Chung Uoo Chang , Chung Won Sub
Published: March 2009

Several methods for loading of Pt-Ni binary catalysts on the CNTs were tested. Using the
CNTs treated HNO3, the catalysts supported Pt, Ni separately(Pt&Ni/CNT) and Pt-Ni alloy(Pt-
Ni/CNTs) were made respectively. The results of supporting were confirmed by TEM and XRD
analysis. TEM images show that metal catalysts were loaded uniformly and finely on the CNTs. By
XRD analysis, the peaks of Pt&Ni/CNTs displayed Pt and Ni peaks respectively. Also it was found
that the peaks of Pt were shifted to the higher 2theta angle in X-ray diffraction pattern which
indicated that Pt-Ni alloy was formed successfully(Pt-Ni/CNTs). In addition, electrochemical tests
for cathode catalysts of DMFC were performed. As the results, Pt-Ni/CNTs was most suitable for
cathode catalysts of DMFC.
Synthesis of Dimethyl Carbonate from Methanol and Carbon Dioxide by Heteropolyacid/Metal Oxide Catalysts
Authors: La Kyung Won , Youn Min Hye , Chung Jin Suk , Baeck Sung Hyeon , Song In Kyu
Published: March 2009

CexTi1-xO2 and H3PW12O40/CexTi1-xO2 catalysts were prepared by sol-gel method,
and they were applied to the direct synthesis of dimethyl carbonate (DMC) from methanol
and carbon dioxide in a batch reactor. The reaction was carried out in an autoclave reactor at
170oC and 5 MPa. It was found that CexTi1-xO2 exhibited a higher catalytic performance than
pure CeO2 and TiO2. The catalytic performance of CexTi1-xO2 was the maximum when
x=0.1. It was also revealed that H3PW12O40/CexTi1-xO2 catalysts showed a remarkably
enhanced catalytic performance than the corresponding CexTi1-xO2 catalysts. The amount of
DMC produced by 15 wt% H3PW12O40/ Ce0.1Ti0.9O2 catalyst was six times higher than that
produced by Ce0.1Ti0.9O2 catalyst. It is concluded that both Brönsted acid sites provided by
H3PW12O40 and base sites in CexTi1-xO2 played an important role in improving the catalytic
performance of H3PW12O40/CexTi1-xO2.
POSS-Containing Nanocomposite Materials for Next Generation Nanolithography
Authors: Choi Jae Hak , Kang Phil Hyun , Nho Young Chang , Hong Sung Kwon
Published: March 2009

Nanocomposite materials based on poly(p-hydroxystyrene-co-2-methyl-2-adamantyl methacrylate-co-methacrylisobutyl-POSS) were synthesized and evaluated as EUV chemically amplified resists. Incorporation of 2-methyl-2-adamantyl and POSS groups into the matrix polymer made it possible to improve the dry-etch resistance, and excellent lithographic performance was obtained. The well-defined 250 nm positive patterns were obtained using a KrF excimer laser scanner, and 100 nm elbow patterns using an EUV lithography tool. The dry-etch resistance of this resist for a CF4-based plasma was comparable to that of poly(p-hydroxystyrene).
Spark Plasma Sintering of Nanoscale (Ni+Al) Powder Mixture
Authors: Kim Ji Soon , Choi Hyeong Suk , Dudina Dina V. , Lee Jeong Keun , Kwon Young Soon
Published: March 2009

An attempt was made to produce nickel aluminides with fine microstructure from
nanoscale nickel and aluminum powders produced by wire electric explosion (WEE). The powders
were mixed and spark plasma sintered (SPS) for simultaneous reaction and densification of the
material. Various mixing methods were tested to give the best homogeneity of the nanopowders
mixtures. Utrasonic pre-treatment of the powders did not result in any positive effect on mixing
homogeneity. Sintered compact contained NiAl and Ni3Al phases, showed fine grain size and
unexpectedly high hardness possibly due to the presence of aluminum oxide in the starting
nanopowders.
Characterization of Nano Scaled Mullite Powders Prepared by Organic-Inorganic Solution Technique
Authors: Lee Sang Jin , Jung Choong Hwan
Published: March 2009

Nano scaled mullite (3Al2O3·2SiO2) powders had been fabricated by an organic-inorganic solution technique using a polyvinyl alcohol (PVA) as an organic carrier. PVA polymer contributed to a soft and porous powder microstructure, and ball milling with the porous powder was effective in making nano-sized mullite powders. In addition, the degree of polymerization of PVA affected the crystallization behavior. The fully crystallized and ball-milled mullite powders had an average particle size of 120 nm with a specific surface area of 67.0 m2/g. In this paper, the simple solution technique and milling process for the fabrication of nano scaled mullite powders are introduced. And the effects of PVA on the crystallization behavior and powder specific surface area are also studied. The characteristics of the synthesized powders are examined by using XRD, TEM, particle size analyzer and nitrogen gas adsorption.
Synthesis and Characterization of Co Nanoparticles by Solventless Thermal Decomposition
Authors: Li Yan , Zhang Xiao Li , Kim Young Hwan , Kang Young Soo
Published: March 2009

Co nanoparticles were synthesized via a solventless thermal decomposition of Co2+-oleate2. The crystalline structure is strongly affected by the thermal treatment of the Co nanoparticles. Further, the annealing also results in the decomposition of surfactant around Co particles. The size of nanoparticles was confirmed by transmission electron microscopy (TEM). The crystal structure of nanoparticles was characterized by X-ray diffraction pattern (XRD). The magnetic properties were characterized by vibrating sample magnetometer (VSM).
Creep Rupture Properties of Type 316LN Stainless Steel Welded by the SAW Process
Authors: Kim Woo Gon , Ryu Woo Seog
Published: March 2009

The creep properties of type 316LN SS welded by the SAW process have been evaluated.
The creep tests for both the base and weld metals were conducted with different stress levels at 550oC
and 600oC. The creep-rupture time of the weld metal did not show a large difference when compared
to that of the base one, though it exhibited a little lower value at 600oC. The creep rate of the weld
metal was lower than that of the base one at the same stress and rupture-time conditions. Especially,
the creep-rupture ductility of the weld metal is found to be decreased by about 60%, compared to the
base one. This is due to the decreasing of tensile elongation and the increasing of the yield stress in the
weld metals.
Surface Slip Markings Of Fatigue-Tested Materials Hardened By Precipitates: Dislocation Dynamics Approach
Authors: Shin Chan Sun , Fivel Marc , Robertson Christian F. , Kim Wheung Whoe
Published: March 2009

Fatigue simulations are performed by using the new parallel discrete dislocation dynamics code. The effects of particles (shearable or non-shearable) on the fatigue properties, e.g. the cyclic mechanical response and the surface markings, are presented. The simulated results are found to represent the features observed in the experiments well. Fatigue of materials containing both shearable and non-shearable particles (bimodal case) is also simulated. The Orowan loops accumulated around the non-shearable particles promote a dispersion of the slips by a local cross slip, and the fatigue features of the bimodal case are in between those of the shearable and the non-shearable particle case.
A Study on the Estimation of Fracture Behaviour for a Circumferentially Through-Wall Cracked Pipe
Authors: Song Weon Keun , Park Jae Sil
Published: March 2009

It is known that fracture characteristics are changed due to the geometric configuration.
Also, it is known that toughness data obtained from the standard specimen test are conservative to
predict fracture behavior of the real piping. Thus fracture behavior by tests of pipes would to be
applied to the integrity evaluation for the piping system. However, fracture test with real pipe is not
only difficult to perform but also very expensive, and requires lots of experience. So an estimation
method of pipe’s fracture behavior is necessary to solve this problem. The objective of this thesis is to
propose a method to estimate the fracture behavior of a pipe from the result of the standard specimen
fracture test. For this, fracture tests for standard specimens and pipes are conducted. The resultant
load - load-line displacement record of the standard specimen was transformed to that of a pipe by
load separation method. To begin with, the load versus load-line displacement curve of a standard
specimen extracted from a pipe is normalized by a geometry function of the CT specimen. Then this
normalized curve was converted to pipe’s load versus displacement curve by a geometry function of
pipe. To verify the constraint factor and the geometric function of pipe, finite element analyses were
performed. To demonstrate the proposed method, experimental results of pipes are compared with
predicted results. Calculated results from CT specimens are similar to experimental results of pipes.
Therefore the transformability from a CT specimen to a pipe by load separation method is proved.
Consequently the applicability of the proposed method was proved.
Friction and Wear of POE and PAG Oils in the Carbon Dioxide Environment
Authors: Oh Se Doo , Cho Sung Oug , Lee Young Ze
Published: March 2009

The carbon dioxide (R-744) as a natural refrigerant has been an attractive alternative
refrigerant to replace HFC (hydrofluorocarbon) refrigerants currently used in air conditioning
systems, due to the environmental concerns. Because new compressors with CO2 are going to be
operated under the high pressure, the tribology of sliding surfaces in the compressor becomes very
important. To develop new compressor, especially scroll type, the friction and wear characteristics
of sliding surfaces between a fixed scroll and an orbiting scroll in the scroll compressor were
investigated in this paper. The sliding tests of pin-on-disk type were carried out between scroll
surfaces under various sliding speeds, normal loads, surface roughness, and refrigerant pressures.
Two types of lubricants were used, namely POE (polyol ester) oil and PAG (polyalkylene glycol)
oil. The friction forces, wear amounts and surface temperatures were monitored during the tests.
Test results showed that the wear amounts increased with increasing normal load and rotating
speed, and also decreased with decreasing surface roughness. Also, the results of the sliding tests
showed that using PAG oil has an advantage over POE oil in CO2 environment. As the pressure of
CO2 refrigerant became higher, the amount of wear and coefficient of friction became larger in
CO2/POE mixed environment, but wear and friction remained constant in CO2/PAG mixed
environment. The wear coefficients in CO2/PAG and CO2/POE mixed environment were 8.60×10-9
㎣/N·m and 2.35×10-8 ㎣/N·m, respectively.
Advanced Active Safety System Using Separated Front and Rear Motor Control for a 4WD Hybrid Electric Vehicle
Authors: Kim Dong Hyun , Hwang Sung Ho , Kim Hyun Soo
Published: March 2009

Vehicle stability in 4 wheel drive(4WD) vehicles has been pursued by torque split based
technology and brake based technology. The brake based methods are essentially brake maneuver
strategies using the active control of the individual wheel brake. By comparison, the torque split
based technologies realize stability by varying the traction torque split through powertrain to create
an offset yaw moment. In the 4WD hybrid electric vehicle adopting separate front and rear motor,
the vehicle stability enhancement algorithm using the rear motor control has some advantages such
as faster response, braking energy recuperation, etc. However, since the left and right wheels are
controlled by the same driving and regenerative torque from one motor, stability enhancement only
by the front and rear motor control has a limitation in satisfying the required offset yaw moment.
Therefore, to obtain the demanded offset yaw moment, a brake force distribution at each wheel is
required. In this paper, a vehicle stability control logic using the front and rear motor and electrohydraulic
brake(EHB) is proposed for a 4WD hybrid electric vehicle. A fuzzy control algorithm is
suggested to compensate the error of the sideslip angle and the yaw rate by generating the direct
yaw moment. Performance of the vehicle stability control algorithm is evaluated using ADAMS and
MATLAB Simulink co-simulation.
The Effects of Acid Treatment Methods on the Diameter Dependent Fracture of Single Walled Carbon Nanotubes
Authors: Baik Seung Hyun , Kim Young Jin , Lee Dock Jin , Choi Jae Boong
Published: March 2009

The effects of acid treatment methods on the fracture of single walled carbon nanotubes
are investigated using gel electrophoresis and Raman spectroscopic techniques. The mechanism of
gel electrophoresis is based on the migration of charged particles in an electric field, and the gel
matrix acts as a sieve for the analyte. A comparative Raman spectroscopy analysis, performed on the
migrated nanotubes in the gel, shows that small diameter tubes are cut shorter by the acid treatments.
Alkali Atoms Intercalating Induced Metal-Semiconductor and Semiconductor-Semiconductor Transitions in Carbon Nanotubes
Authors: Yang Xiao Bao , Ni Jun
Published: March 2009

We show that the intercalating of alkali atoms with adequate concentration can transform a
metallic single-walled carbon nanotube (SWCNT) into a semiconductor tube or a semiconductor
SWCNT into a semiconductor tube with different band gaps due to a unique feature of the band
structures in SWCNTs. Results of Li2C60 in the (5,0) tube, Li2C112 in the (4,2) tube and K2C112 in the
(7,0) tube show that this transition mechanism is quite general.
Molecular Dynamics Simulation and Analysis on the Stress Induced Crystallization Behavior of Metallic Glass Cu
Authors: Wang H.L. , Wang Xiu Xi , Liang H.Y.
Published: March 2009

The compressive deformation of metallic glass Cu was studied under uniformly distributed
strains with different rates at 1 K temperature using molecular dynamics simulations. The interaction
between atoms in the system adopts the embedded atom method (EAM) reported by Mishin. We
found that MG Cu is an elastic/perfect plastic material and the Young modulus is about 50 Gpa with
strain rates from 0.1ns-1 to 10 ns-1. At low strain rates the sample deforms inhomogeneously and the
amorphous phase transforms continuously to a crystalline phase. It was observed that the nucleation,
growth and mergence processes of crystalline are induced by stress. At high strain rates the system
passes through plastic deformations homogeneously and keeps the amorphous structure. The higher
flow stress occurs at higher strain with the strain rate increasing. The stress effect is an important
factor that induces MG crystallization just like temperature effect. The relationship between
characteristic nucleation rate and strain rate determines the different deformation mechanism of MG.
Atomistic Study of the Strain- and Size-Dependence of Poisson’s Ratio of Single-Walled Carbon Nanotubes
Authors: Ni Xian Gui , Zhang Z. , Wang Y. , Wang Xiu Xi
Published: March 2009

Three armchair single-walled carbon nanotubes (SWCNTs) (7, 7), (12, 12), (17, 17) and
three zigzag SWCNTs (12, 0), (16, 0), (20, 0) are investigated in this paper, using the molecular
dynamic (MD) method with the second-generation Tersoff-Brenner (TB) potential. The Poisson’s
ratio of these nanotubes under tensile and compressive loading is obtained. The effect of the strain
and size on the Poisson’s ratio of nanotubes is analyzed systematically, from the viewpoints of the
structure and the averaged atomic potential energy of nanotubes. The results show that the Poisson’s
ratio of nanotubes decreases as the strain increases. The Poisson’s ratios of nanotubes of larger chiral
angle decrease more quickly. For nanotubes of the same chiral angle, the larger the diameters of
nanotubes are, the larger their Poisson’s ratios become. Moreover, the Poisson’s ratios of nanotubes
of larger diameter are more approaching.
Investigating the Nanoparticle Transition from Bulk Behavior to Discrete Atom/Finite Size Behavior Using Laser Induced Pressure Generation
Authors: Gerstman Bernard S.
Published: March 2009

Detailed investigations have been carried out [1,2] on the response of microparticles
and nanoparticles to lasers of various pulse durations and energies. A first principles model has
been developed that allows the prediction of all thermo-mechanical effects that will be generated
from any laser pulse, such as pressure generation and phase changes. This theoretical work also
predicts the thermo-mechanical effects transmitted to the surrounding transparent medium that
the nanoparticles are immersed in, such as water or a solid polymer. The use of short enough
pulses produces shock fronts in the surrounding medium. We calculate how short the laser pulse
must be as a function of nanoparticles properties. We also show that measurements of pressure
peaks in the medium can be used to determine the thermo-mechanical properties of the absorbing
nanoparticles, such as bulk modulus and thermal expansion coefficient. Because the
measurements can be made in the surrounding medium, they are easier to perform
experimentally. Using this approach on particles of decreasing size, measurements of the
pressure in the medium allow the determination of the size at which a nanoparticle is small
enough to deviate from its bulk behavior and manifest discrete atom, finite size effects. This
allows the prediction of how the thermo-mechanical properties of nanoparticles will change as
their size decreases.
A Computational Model for Nanoscale Self-Assembly of Monolayer Surfaces
Authors: Bao Yan Gang , Wang Xiao Dong
Published: March 2009

A computational model is proposed to analyze the nanoscale self-assembling
phenomenon of monolayers on heterogeneous surfaces. Morse potential is used to describe the pairpotential
between molecules or atoms. Minimization of free energy is used to regulate different
phases and lattices to form optimized heterogeneous structures of different sizes with periodical
patterns. A representative volume element (RVE) is first defined and an optimization algorithm is
developed to adjust the positions of particles in it to reduce its potential until global equilibrium is
reached. The pair-potential distribution in the monolayer and the substrate layers are studied. It is
interesting to observe that the pair-potential distribution in the substrate layers resumes uniformity
just a few layers away from the interfacial boundary.
Modeling and Simulation of Carbon Nanotube Interconnect Network
Authors: Dong Chen , Wang Wei , Rizkalla Maher
Published: March 2009

The electrical properties of metallic carbon nanotubes (CNT) can rival, or even exceed, the best
metals known. It is a potential candidate for future on-chip interconnect, whose performance will be
dominant in the next generation integrated circuits. In this paper, a study on the modeling and simulation
techniques for the CNT interconnect network is carried out. The frequency-independent models of CNT
interconnects in terms of resistance, inductance and capacitance are summarized. A novel frequencydependent
circuit model is proposed for CNT for various high-frequency applications. Preliminary analysis
shows a good match between numerical simulations and the compact model. The proposed modeling and
simulation techniques for CNT interconnect network are expected to play an important role in the future
CNT nanotechnology applications.
Ab Initio Simulations of Low-K and Ultra Low-K Dielectric Interconnects
Authors: Tan Vincent B.C. , Dai L. , Yang S.W. , Chen X.T. , Wu P.
Published: March 2009

Ab initio molecular dynamics simulations were carried out to study low-k/ultra low-k
dielectric systems comprising Cu/Ta/SiLK-like polymer. A study of the motion of single metal
atoms of Cu and Ta in the SiLK-like polymer showed that Cu atom motions are effected by jumps
between cavities inside the polymer and that Ta is more sluggish than Cu not only because of its
larger mass but also because of stronger affinity to the polymer. It was also found that crosslinking
of the polymer did not affect the motion of the metal atoms. Simulations of deposition showed that
a thin Ta diffusion barrier does not have good structural integrity to prevent Cu-diffusion when
directly deposited onto the SiLK; the barrier performance was greatly improved after introducing a
Si-based film between the Ta and SiLK.
The Influences of Size and Anisotropy Strength on Hysteresis Scaling for Anisotropy Heisenberg Multilayer Films
Authors: Huang Zhi Gao , Lai Heng , Zhang Jian Min , Li Jia Xin , Zhang Feng Ming , Du You Wei
Published: March 2009

In this paper, we simulate the magnetization dynamic processes of the multilayer films,
and calculate their hysteresis loop areas using Monte Carlo method. The simulated results indicate
that, the size and anisotropy strength of the anisotropy multilayer films influence evidently the
dynamic phase transition, and the phase transition temperature increases with enhancing values of
the anisotropy constant and layer thickness. It is also found that, with increasing number of layers of
films, the value of α decreases, while the magnitudes of β and γ increase. On the contrary, with
increasing anisotropy strength, the value of α increases, while the magnitudes of β and γ reduce.
The Effect of CdS Nanorods on the Morphology of Electrospun Poly(Vinyl Pyrrolidone) Products
Authors: Li X. , Wang C. , Li Y. , Chu H.B. , Li L.J.
Published: March 2009

The CdS/PVP fibers have been successfully prepared by electrospinning. Scanning
electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis absorption spectra
were used to characterize the structure. Results showed that the concentration of polymer solutions
and the CdS amount in the solvent influenced the morphology and the diameter of the electrospun
fibers. The electrospinning from CdS/PVP in ethanol produced a structure having a combination of
fibers, ribbons, beads and an unexpected half hollow sphere (HHS) structure. When the weight ratio
of CdS:PVP was kept at 1:1000, the morphologies of electrospun products changed from HHS, to
beaded fibers and ribbons, to beaded fibers, and to bead-free fibers with the increasing of the PVP
concentration.
Several Fundamental Problems in Hydrophobic Force Measurements by Using AFM
Authors: Xu Hui , Xu Guo Hua , An Yue
Published: March 2009

Several fundamental problems in hydrophobic force measurements by using AFM are
discussed in this paper. A novel method for colloid probe preparation based on the chemical etching
technology is proposed, which is specially fit for the unique demands of the hydrophobic force
measurements by AFM. The features of three different approaches for the determination of spring
constants of the rectangular cantilevers, including geometric dimension, Cleveland and Sader
methods are compared. The influences of the sizes of the colloids on the measurements of the
hydrophobic force curves are investigated. Our experimental results showed that, by selecting a
colloid probe with a proper spring constant and a tip size, a real hydrophobic force, even the
complete hydrophobic interaction force curve with every subtle change in details might be
measured by using AFM.
Rheological Properties of Water Films Nanoconfined in Parallel Au Plates by Molecular Dynamics Simulations
Authors: Liao M.L. , Ju Shin Pon , Lin Jenn Sen , Lin Y.S.
Published: March 2009

Rheological properties of water films nanoconfined in two parallel Au plates are
investigated with the aid of molecular dynamics simulations. The density distribution, velocity
profile, and diffusion coefficients of the water film in a Couette flow are studied. Shear viscosity
and its dependence on the shear rate of the water film are also examined in the present research. It is
found that the density of the water molecules near the plates is much higher than that in the other
regions. This indicates that many water molecules are adsorbed by the plates and adsorbed layers
are formed in the vicinity of the plates. The diffusion of the whole film increases dramatically as the
shear rate becomes greater than 1010 s-1. The shear viscosity decreases as the shear rate increases,
especially for the water film with a small thickness, which indicates the shear-thinning behavior for
viscosity of the nanoconfined film. Moreover, an increase in shear viscosity with a decrease in the
film thickness can also be found in the present study.
A Stochastic Model for Current and Voltage Oscillations of the Si Electrode
Authors: Carstensen Jürgen , Föll Helmut , Foca E. , Fang Cheng
Published: March 2009

In this work we present a theoretical model that explains the current and voltage oscillations
at the Si electrode in HF media. A simulation computer program based on this model is implemented
and results are shown. Oscillations of the current and (for the first time) the voltage obtained
numerically fit perfectly with experiments. The model allows to obtain more information
about the system in the form of maps (accompanied by histograms) of e.g.: oxide thickness distribution,
SiO2/HF and Si/SiO2 interfaces morphology, or local voltage losses. Other characteristics of
the oxide like capacitance or roughness can also be obtained.
Analysis of Modes in the Nanowire Cavity by FDTD Simulation
Authors: Wang Miao Qing , Cai Zhi Ping , Huang Yong Zhen , Chen Qin , Luo Xian Shu
Published: March 2009

The mode frequency and the quality factor of nanowire cavities are calculated from the
intensity spectrum obtained by the finite-difference time-domain (FDTD) technique and the Padé
approximation. In the free-standing nanowire cavity with the dielectric constant 6.0 and the length
of 5 μm, the quality factors of 130, 159, and 151 are obtained for HE11 with frequency around 798
THz, at the cavity radius of 60nm, 75nm, and 90nm, respectively. The Q-factor of 78 is also
calculated in the nanowire with length of 5 μm and radius of 60nm grown on the sapphire substrate
with refractive index 1.8. The obtained mode field distribution of the fundamental transverse mode
shows that the mode field confined very well by the nanowire cavity even when the radius of
nanowire is much smaller than the mode wavelength.
Anisotropic Growth of Metal Chains on Anisotropic Substrate
Authors: Wu Feng Min , Fang Yuh Zhang
Published: March 2009

Based on the exchange mechanism of metal islands growth on anisotropic metal
surfaces, the growth processes of anisotropic Cu islands on the anisotropic Pd (110) surface are
investigated by Monte Carlo simulations with realistic growth model and physical parameters.
The anisotropic diffusion and anisotropic sticking of Cu adatoms are included in the simulation
model after being considered the anisotropy of Pd (110) surface and compared to the experiments.
It is found that the larger diffusion rate along the [110] channels of Pd (110) surface gives rise to a
slower growth rate of Cu island in this direction, unless special effect of the anisotropic sticking is
invoked. The simulation results show that the shape anisotropy of Cu islands is mainly due to the
sticking anisotropy rather than the diffusion anisotropy.
Formation and Magic Number Characteristics of Cluster Configurations During Rapid Cooling Processes of Liquid Metals
Authors: Liu Rang Su , Liu F.X. , Zhou Qin Yuan , Wang X. , Zheng C.X.
Published: March 2009

A molecular dynamic simulation study has been performed for a large-sized system
consisting of 106 liquid metal Al atoms to deeply investigate the formation and magic number
characteristics of various cluster formed during solidification processes. It has been found that the
numbers of various types of cluster in the system obviously possess peak values, namely, magic
numbers. The first, second, third, .…,and tenth magic numbers are determined in turn in the order of
13, 19, 25(27), 31(33), 38(40), 42(45), 48(51), 55(59), 61(65), 67,…( the numbers in the brackets
are the second peak values in the corresponding level of cluster). This magic number serial is in
good agreement with the experimental results obtained by Harris et al, and this method determining
the magic numbers from the clusters according to the level of basic cluster can be used to afford a
primary scientific and reasonable explanation to experimental results.
Kinetic Monte Carlo Simulation of Nucleation and Growth Behavior in Surfactant-Mediated Epitaxy
Authors: Wang D.M. , Ding Z.J.
Published: March 2009

The behavior of island shape transition and nucleus density evolution in the early stage of
epitaxial growth mediated by a monolayer of surfactant is studied by using a kinetic Monte Carlo
simulations. The main kinetic processes included in the model are deposition, diffusion of atoms,
exchange of adatoms with their underneath surfactant atoms, and reexchange in which an exchanged
adatom resurfaces to the top of the surfactant layer. The simulation produces pattern transitions from
small compact islands at low temperatures, to fractal-like islands at intermediate temperatures where
the deposited adatoms can be easily incorporated into the surfactant layer, and then to regular
compact islands at high temperatures where the reexchange becomes active. The island density as a
function of temperature exhibits a complex N-shape. These results provide a reasonable explanation
for the observed temperature dependence of the growth mode in existing experiments.
Stiffness Prediction of Nano-Fibers Composite Ceramics
Authors: Zheng Jian , Ni Xin Hua , Yao Zhan Jun
Published: March 2009

Nano-fibers composite ceramics were mainly composed of fiber eutectics with random
orientation, in which nanometer sized second fibers are dispersed within the ceramic matrix. First,
Mori-Tanaka method was used to predict the stiffness of the fiber eutectic structure. The fiber
eutectic structure is transverse isotropy and has five independent elastic constants. Then considering
random orientation of the fiber eutectic structure, the Young’s modulus and Poisson’s ratio of
composite ceramics is determined by mean strain. Composite ceramics is isotropy. When the
volume fraction of nano-fibers increase, the Young’s modulus of composite ceramics decrease and
are little smaller than the volume average value, the Poisson’s ratio of composite ceramics decrease
and are little bigger than the volume average value.
Surface Boundary Effect in Electron-Solid Interactions
Authors: Salma Khanam , Ding Z.J.
Published: March 2009

Electrons impinging or escaping from a solid surface undergo surface electronic
excitations which are competitive in nature to other electron-solid interaction channels. The detailed
information about electron inelastic scattering probability for surface excitations at solid surface is
also important in reflection electron energy loss spectroscopy. A self energy formalism based on
quantum mechanical treatment of interaction of electrons with a semi-infinite medium, which uses
the optical dielectric function is considered to study surface boundary effect for planar surfaces of
Cu and Ni for various conditions of electron-solid interactions. The total surface excitation
probability of an electron while crossing the surface boundary once is numerically computed by
integrating surface term of spatial and angular dependent differential inelastic cross sections over
energy loss and distance from the surface. It is found that surface effect is prominent for low energy
electrons and large oblique angles with respect to surface normal and confined to the close vicinity
of surface boundary.
Surface-Area-Difference Model for Melting Temperature of Metallic Nanocrystals Embedded in a Matrix
Authors: Qi Wei Hong , Wang Ming Pu , Li Zhou , Hu Wang Yu
Published: March 2009

The cohesive energy is the energy to divide the crystal into isolated atoms,
and the direct result of cohesive energy is to create new surface. The increased surface
energy should equal the cohesive energy of the crystal, which results from the surface
area difference between the total atoms and the crystal. This is the basic concept of
Surface-Area-Difference (SAD) model. The SAD model has been extended to account
for the melting temperature of metallic nanocrystals with non-free surface (embedded
in a matrix) in the present work. It is shown if the melting temperature of the matrix
must be much higher than that of the bulk value of the nanocrystals, and the
nanocrystals has coherent or semi-coherent interface with the matrix, the nanocrystals
may be superheated. The present results are supported by the available experimental
values.
Theoretical Study of Differences between Surface and Bulk Electronic States in Cu Clusters
Authors: Dai Ying , Huang Bai Biao , Long Run , Yu Lin
Published: March 2009

The size-dependent electronic structures of metal clusters Cun (n=2-20) have been
calculated using density functional theory method. The results reveal that their electronic properties
are almost the same as bulk material if the cluster size larger than a critical value. The properties can
be understood by a surface-noncrystalline-layer model that composed of an interior crystalline-like
core and an outer surface noncrystalline layer.
A Novel Magnetostrictive Drive Rotary Motor
Authors: Zhou Jian Jun , Pan Yu Liang , Huang Min
Published: March 2009

Piezoelectric motors have been successfully developed for various applications like
autofocus drives in camera lenses and manufacturing equipment for semiconductor production. Their
high speed and accurate positioning capability, combined with a moderate holding torque, make
piezo motors also very attractive for actuation purposes in spacecraft mechanisms. However, these
motors require high driving voltage and have only a small driving torque. In this paper, the authors
have developed a novel magnetostrictive rotary motor using Terfenol-D (Tb0.3Dy0.7Fe1.9) material as
the driving elements. The small movement of the magnetostrictive actuator is scaled to 3 times by
using flexible flexure hinges, a special designed mechanism is used to combine 3 such actuators to
form a pure rotation movement and this movement is used to drive the rotor of the motor. Prototype of
this research is made and a commonly 3-phase alternating current is used to drive the motor.
Experiments are also carried on in the lab of School of Mechanical and Electrical Engineering of
Hangzhou Dianzi University.
Development of Robust Microvavles for Compact Robust Pumps/Hydraulic Actuators
Authors: Li B. , Chen Q.
Published: March 2009

In situ UV-LIGA assembled robust micro check valves with large flow rates (>10
ml/s, displacement related), high-pressure support ability (>10 MPa) and high
operational frequencies (>10 kHz) made of nano-structured nickel were presented in
this paper. The microvalve consists of an array of 80 single micro valves to achieve the
required flow rates. Test results show that the forward flow rate is about 19 ml/s under
pressure of 90Psi. The backward flow rate is negligible. The reliability of the valve is
ensured by the valve design and nanostructured nickel realized. The tested tensile
strength of a nano structured nickel is about 1GPa. The strength of SU-8 is 50MPa,
which is more than 50% higher that fabricated with a standard process.