bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Biodegradable Nanocomposites by Incorporation of Functionalized Carbon Nanotubes
Authors: Kim Hun Sik , Park Byung Hyun , Yoon Jin San , Jin Hyoung Joon
Published: March 2009

Polymeric carbon nanotube composites constitute one of the most promising alternatives
to conventional filled polymers. The dispersion of nanometer-sized carbon nanotubes in a polymer
matrix markedly improves its physical properties. This approach can also be applied to
biodegradable synthetic aliphatic polyesters such as poly(L-lactic acid) (PLLA), which has been
receiving an increasing amount of attention due to environmental concerns. In this study, the
mechanical properties of PLLA were enhanced by the incorporation of a small amount of carbon
nanotubes (0.8 wt%) in the solution state, which could make this material a good competitor for
commodity materials such as general purpose plastics, while allowing it to retain its
biodegradability. In order to obtain a homogeneous dispersion of the carbon nanotubes in the
matrix, oxygen-containing groups were introduced on the surface of the MWNTs. The good
dispersion of the nanotubes in the PLLA matrix observed by scanning electron microscopy was
attributed to the fact that the PLLA was compatible with the functionalized MWNTs during the
compounding process. The electrical conductivity of the composites was also investigated.
Inspecting Carbon Matrix Composites with Airborne/Conventional Ultrasound
Authors: Sim Jae Ki , Im Kwang Hee , Hsu David K. , Song Sung Jin , Cho Hyeon , Kim Hak Joon , Seo Young Hwan , Yang In Young
Published: March 2009

Carbon/phenolic composite (CPC) materials have obvious advantages over conventional
materials, which are consisting of carbon fibers embedded in a carbon matrix. The CPCs have
become to be utilized as parts of aerospace applications and its low density, high thermal
conductivity and excellent mechanical properties at elevated temperatures make it an ideal material
for aircraft brake disks. Because of permeation of coupling medium such as water, it is desirable to
perform contact-less nondestructive evaluation to assess material properties and part homogeneity.
In this work, a C/P(Carbon/phenolic) composite material was characterized with non-contact and
contact ultrasonic methods using automated acquisition scanner. Also through transmission mode
was performed because of the main limitation for air-coupled transducers, which is the acoustic
impedance mismatch between most materials and air. Especially ultrasonic images and velocities
for C/C(Carbon/Carbon) composite disk brake was measured and found to be consistent to some
degree with the non-contact and contact ultrasonic measurement methods. Low frequency throughtransmission
scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for
mapping out the material property inhomogeneity. Measured results were compared with those
obtained by the motorized system with using dry-coupling ultrasonics and through transmission
method in immersion. Finally, results using a proposed peak-delay measurement method well
corresponded to ultrasonic velocities of the pulse overlap method.
Effect of Fiber Aspect Ratio and Area Ratio Getting to Accuracy of Intensity Method in Fiber Orientation Angle Distribution Measurement
Authors: Kim Jin Woo , Lee Dong Gi
Published: March 2009

Measurement of fiber orientation distribution state is very important constituent to find out
decision of processing condition of product or mechanical special quality of moldings in fiber
reinforced polymer composite material. Therefore, reliable measurement method of fiber orientation
angle distribution is established, and need researcher about simplicity measuring method urgently the
nondestructiveness. In this research, to investigate about accuracy of fiber orientation angle
distribution measurement of fiber reinforced composite material by intensity method, find fiber
orientation function value that is measure of fiber orientation distribution state constructing fiber
orientation simulation picture by plotter changing diameter and length and orientation state of fiber.
Recognize this fiber orientation simulation picture by image scanner, and measure fiber orientation
angle distribution state by this realized intensity information. This time, I wish to measure reliable
fiber orientation angle distribution comparing fiber orientation function calculation value saving in
the advance with fiber orientation function value that is measured by intensity method. The results
show that measurement accuracy of the fiber orientation angle distribution by intensity method is
affected by the fiber aspect ratio when the total length of oriented fiber is same. The average gradient
of fiber orientation function is 0.94 for 1000mm of the total fiber length and is 0.93 for 2000mm when
the fiber aspect ratio is over 50. Measurement accuracy by intensity method is about 94% and the
reliable data can be obtained by intensity method.
Damage Development in CFRP Laminates under Impact Loading
Authors: Jang Seung Min , Adachi Tadaharu , Yamaji Akihiko
Published: March 2009

The development characteristics of impact-induced damage in carbon-fiber-reinforcedplastics
(CFRP) laminates were experimentally studied using a drop-weight impact tester. Five
types of CFRP laminates were used to investigate the effect of stacking sequences and thicknesses.
The efficiency of absorbed energy to impact energy was different for CFRP laminates with different
stacking sequences or thicknesses. The DA/AE ratio of delamination area (DA) to absorbed energy
(AE) was almost the same for CFRP laminates with the same stacking sequence regardless of the
thickness. We found that the DA/AE ratio could be used as a parameter to characterize the impact
damage resistance in CFRP laminates with different stacking sequences.
Microstructure and Mechanical Properties of Al2O3-TiC/Al in Situ Composites
Authors: Chen Hong Mei , Yu Hua Shun , Zhang Jing , Zhang Lin , Min Guang Hui
Published: March 2009

The Al2O3-TiC/Al composites were prepared by injecting CO2 gas into Ti contained Al-Si
alloy melts. The microstructure of the composites was examined by XRD, SEM and TEM. It was
indicated that both Al2O3 and TiC particles can be formed by the in situ reaction of CO2 with Ti and
Al in the melten alloys. The Al2O3 and TiC particles in size of 0.3~1.5μm distributed uniformly in
the matrix. The volume fraction of the particles is mainly depend upon the time of CO2
injection.The tensile strength at room temperature of the composites can reach 346.08MPa and the
hardness is 149.6MPa HBS, repectively, which are higher than those of the matrix alloy.
Development of Accelerated Life Test Method of Hydraulic Pump
Authors: Jung Dong Soo , Kim Hyoung Eui , Kim Sung Hun , Kang E Sok
Published: March 2009

This paper proposes a new accelerated life test method of hydraulic pump used in
vehicles, which have multiple alternating loads. For determination of life time of hydraulic pump
for given field conditions with respect to duty cycle, the equivalent load and speed of this unit has
to be determined. Equivalent load and speed can be calculated from the given duty cycle using the
predominant theory for cumulative fatigue damage. Finally, we can perform accelerated life test on
hydraulic pump by determination of test pressure and speed from calculated equivalent cumulative
damage per working cycle and weighted average speed.
Measurement of Mechanical Properties and Residual Stresses of Bridged Gold Films and Circular Gold Membranes
Authors: Choi Woo Sung , Choi S.T. , Son Sang Uk , Lee Seung Seob , Yang S.Y. , Earmme Y.Y.
Published: March 2009

In order to measure the mechanical properties of gold films on silicon substrate, two
types of specimens, i.e., bridged films and circular membranes, are manufactured. Using a wedge
tip, the bridged gold films are indented so that the films are pushed off, which is called as V-peel
test. The load-deflection curves obtained by the V-peel test are analyzed with the concept of
geometrically nonlinear beam by using the minimum potential energy theory together with Ritz
method. Thus, Young’s modulus and residual stress of the bridged gold films are obtained. Blister
test is also conducted to measure the Young’s modulus and residual stress of a circular gold
membrane, of which deformation is measured by Twyman-Green interferometer. By gradually
increasing the external pressure applied on the membrane, the interfacial fracture toughness
between the gold membrane and silicon substrate is measured based on the concepts of interfacial
fracture mechanics.
An Experimental Method for Micro-Scale Uniaxial Tension Test
Authors: Tang Zhong Bin , Xu Fei , Li Yu Long , Xu Wu Jun
Published: March 2009

A micro-scale uniaxial tension test method for measuring material mechanical properties
of thin film materials is introduced in this paper. A self-developed test device is established based
on the CMT8202 tension test machine. The Interference Strain/Displacement Gauge (ISDG)
method is used to measure the strain in the micro-samples. The three dimensional finite element
method (FEM) is utilized to optimize specimen geometry configuration and to reduce the stress
concentration in specimen around grip region. The experiments are carried out for the
polycrystalline copper thin film. The results show that stress-strain curves and the Young’s modulus
of the thin film material can be obtained by micro-scale tension test. The Young’s modulus
determined by micro-sample for polycrystalline copper thin film has a good agreement with
published results.
MEMS Based Metal Plated Silicon Package for High Power LED
Authors: Lee Sung Jun , Park Ji Hyun , Lim Chang Hyun , Jeong Won Kyu , Choi Seog Moon , Oh Yong Soo
Published: March 2009

By the development of high power LED for solid states lighting, the requirement for
driving current has increased critically, thereby increasing power dissipation. Heat flux corresponds
to power dissipation is mainly generated in p-n junction of LED, so the effective removal of heat is
the key factor for long lifetime of LED chip. In this study, we newly proposed the silicon package
for high power LED using MEMS technology and estimated its heat dissipation characteristic. Our
silicon package structure is composed of base and reflector cup. The role of base is that settle LED
chip at desired position and supply electrical interconnection for LED operation, and finally transfer
the heat from junction region to outside. For improved heat transfer, we introduced the heat
conductive metal plated trench structure at the opposite side of LED attached side. The depth and
the diameter of trench were 150 and 100um, respectively. Copper with high thermal conductivity
than silicon was filled in trench by electroplating and the thickness of copper was about 100um.
Reflector cup was formed by anisotropic wet etching and then, silicon package platform could be
fabricated by eutectic bonding between base and reflector cup. The thermal resistance of silicon
package was about 6 to 7K/W from junction to case, and also, thermal resistance reduction of
0.64K/W was done by metal plated trench. This result could be comparable to that of other high
power LED package. Our silicon package platform is easy to be expanded into array and wafer
level package. So, it is suitable for future high efficiency and low cost package.
Integrated Tunneling Device for High Sensitive Sensor Applications
Authors: Lee Dong Weon , Choi Young Soo , Oh Il Kweon
Published: March 2009

This paper describes an integrated tunneling sensor for applications of an electronic nose and a
scanning probe microscope. Ultra-thin silicon dioxide having a thickness of ~2 nm is used as a
material of the tunneling sensor. It provides much higher sensitivity in comparison with others
sensing methods. The tunneling sensor is placed on a fixed edge where the maximum strain arises.
As additional masses or forces are added to the surface of the cantilever, the thickness of the thin
silicon dioxide layer is slightly decreased. By using exponential nature of electron tunneling
dominated by the thickness of the silicon dioxide it can be used as an ultra-high sensitive sensor.
The thin dioxide is fabricated by dry oxidation using a vertical furnace. The cantilever structures are
defined by conventional MEMS technologies. Current density of the tunneling sensor is evaluated
as a function of voltage and is compared with numerical analysis based on direct tunneling
phenomena.
Fabrication and I-V Characteristics of Nanocrystalline Titania Electrode Sensitized by Zinc Phthalocyanine
Authors: Wang Yu Qiao , Liu Chun Ping , Li Kang , Sun Yue Ming
Published: March 2009

TiO2 colloids prepared by sol-gel method were autoclaved and then deposited onto a
transparent conducting oxide substrate by screen-printing. The TiO2 films electrode was
characterized by XRD, SEM, AFM and Alpha-Step profilometer and then sensitized by zinc
phthalocyanine (ZnPc), 2,9,16,23-tetracarboxy zinc phthalocyanine (ZnTCPc) and ZnTCPc/lauric
acid respectively. Photocurrent density (I) and photovoltage (V) of the electrode were measured
with the solar simulator. The ZnTCPc-sensitized electrode was found the best performance with the
short-circuit photocurrent density (Isc) 16.66 3A/cm2, the open-circuit photovoltage (Voc) 277.9 mV
and the fill factor (FF) 0.39. And the ZnPc-sensitized electrode was found the worst performance
with Voc 114.2 mV, Isc 2.26 3A/cm2 and FF 0.31. It was also found that lauric acid promoted Voc of
the the ZnTCPc sensitized system.
Fabrication of Organic Thin Film Transistor(OTFT) Array by Using Nanoprinting Process
Authors: Jo Jeong Dai , Kim Kwang Young , Lee Eung Sug , Esashi Masayoshi
Published: March 2009

The flexible organic thin film transistor(OTFT) array to use as a switching device for an
organic light emitting diode(OLED) was designed and fabricated in the nanocontact printing and
low-temperature process. The gate, source, and drain electrode patterns of OTFT were fabricated by
nanocontact printing process. And dielectric layer of parylene and organic active semiconductor
layer of pentacene formed at room temperature or at a temperature lower than 40. The
nanocontact printing process using SAM and PDMS stamp made it possible to fabricate OTFT
arrays with channel lengths down to even submicron size, and reduced the fabrication process by 10
steps compared with photolithography. Since the process was done in room temperature, there was
no pattern shrinkage, transformation, and bending problem appeared. Also, it was possible to
improve electric field mobility, to decrease contact resistance, to increase close packing of
molecules by SAM, and to reduce threshold voltage by using a parylene.
Surface Characterization of the Milled–Silicon Nitride Nano Powders by XPS and TEM
Authors: Park Dae Chul , Yano Toyohiko , Kim Sae Hoon , Choi Won Youl , Cho Jung Hee
Published: March 2009

We studied the surface characterization of milled–silicon nitride nano-powders by XPS
and TEM. The change of the chemical state and morphology of the oxide layer on the surface of
Si3N4 nano-particles before and after a conventional wet–ball–milling process are investigated by
X–ray photoelectron spectroscopy for measuring the chemical state of the oxide layer and
transmission electron microscopy for observing surface morphology. The native oxide layers of
as-received Si3N4 powders confirmed by HREM observation and their chemical states were
different each other. As increasing ball–milling time, the chemical composition and the volume of
oxide layer in Si3N4 powders were changed. The chemical state of as–received Si3N4 powder was
near to SiO2 phase. After ball–milling process for long time, that of the milled Si3N4 powder
shifted to Si2N2O phase. As increasing ball-milling time, the oxide layer of Si3N4 powder was also
increased.
Super Fine Powderization of Korean Ginseng Using Low Temperature Turbo Mill
Authors: Lee Beom Goo , Jeong Yeon Ho , Cho Dong Ha , Lee Kang Yol , Kang Wie Soo
Published: March 2009

It is investigated whether ginseng can be milled into super fine powder below 50μm, changing the circumferential velocity of impeller of a turbo mill(100, 110 and 120m/s). The mean particle size is 113.3μm in control but is decreased abruptly into 11.9μm at 120m/s. The largest particle diameter at 97% of volume distribution is reduced into below 32μm at 120m/s from below 725μm at control. The particle size distribution between d(0.1) and d(0.9) is 334μm at control, but is decreased into less than 26μm in all conditions after milling. It shows that ginseng can be milled into super fine powder by the turbo mill, which has the narrow particle size distribution.
Injection Molding Nano and Micro Pillar Arrays
Authors: Yoo Young Eun , Seo Young Ho , Kim Seong Kon , Je Tai Jin , Choi Doo Sun
Published: March 2009

An injection molding technology is developed to replicate pillars in micro/nano scale on the thin
plastic substrate. Two types of pillar are to be replicated and one is square type of 10um x 10um,
the other is circular type whose diameter is in range of 100 nm ~ 300 nm. For both types of the
pillars, the height is about 250 nm. A pattern master is first fabricated on the photo resist(PR) layer
spin coated to about 250nm of thickness on chrome/quartz plate by patterning e-beam writing and
then developing the PR. The patterns on the PR master are transferred by nickel electro-plating to
fabricate rigid nickel stamper. Using this nickel stamper, a substrate with nano pillars on its surface
is injection molded by optimizing the conditions to fabricate DNA separating chip.
Nondestructive Evaluation of Titanium-Nitride Ceramic Coatings
Authors: Yang Dong Ju , Song Sung Jin , Kim Hak Joon , Wang Wen Wu , Kwon Sung Duk
Published: March 2009

Titanium-nitride (TiN) ceramic coatings are widely utilized to extend the lifetime of mechanical parts under
severely abrasive conditions and in lubrication environment. Since ceramic layers coated on machinery components
inevitably experience the changes in their properties, it is necessary to evaluate the characteristics of ceramic coating layers
nondestructively for the reliable use of coated components and the remaining life prediction. For this purpose, in the
present study, the ultrasonic backward radiation technique is applied to evaluate very thin TiN ceramic layers coated on
AISI 1045 steel and austenitic 304 steel substrates. In this study, very interesting behaviors are revealed from the
interrogated TiN ceramic coated specimens. The sliding loading in the abrasive wear regime increases the peak amplitude
of the profile. However, the sliding loading large enough to produce scuffing finally decreases the peak amplitude of the
profile while the peak angle increases.
Optical Interferometric Inspection of Surface Contour of MEMS-Components
Authors: Tay Cho Jui , Wang S.H. , Quan C.
Published: March 2009

In this paper, we describe an optical interferometer applied to 3D inspection of microcomponents.
The resulting interference fringes that are related to the deformation and surface
contour of MEMS-components are analyzed by the fast Fourier transform (FFT) and 3-step phaseshifting
algorithms. Experimental results show the feasibility of the proposed method for 3D
deformation and surface contour measurement of micro-components.
Prediction of Motorized Rotating Pancake Coil Probe Signals Simulated by Numerical Analysis in SG Tubes
Authors: Yoo Joo Young , Song Sung Jin , Jung Hee Jun , Yu Hyung Ju , Choi Young Hwan , Kang Suk Chull , Lee Dong Hoon
Published: March 2009

Signals acquired from a Combo calibration standard tube used to calibrate for inspection
and evaluation of motorized rotating pancake coil probe signals from steam generator tubes. So,
Combo tube signals should be consistent and accurate since they have strong influence on evaluation
procedure of signals. However, motorized rotating pancake coil probe signals are very easily affected
by various factors so that they can distort amplitudes and phase angles which are quantitative terms
for signal evaluation. To overcome this problem, we explored possibility of using numerical
simulation as a practical calibration tool for the evaluation of real field signals. In this study, we
investigated the characteristics of a motorized rotating pancake coil probe and a Combo tube. And
then we used commercial software to produce a set of calibration signals and compared to the
experiments. Using simulated Combo tube signals, we evaluated deliberated single circumferential
indication defects, and these results were compared with experimental signal evaluation results.
Interconnect Design and Thermal Stress/Strain Analysis of Flip Chip Packaging
Authors: Liu Chang Ming , Lee Chang Chun , Ku Hsiao Tung , Chiu Chien Chia , Chiang Kuo Ning
Published: March 2009

As the interconnection density of electronic packaging continues to increase, the fatigueinduced
solder joint failure of surface mounted electronic devices become one of the most critical
reliability issues in electronic packaging industry. Especially, prediction of the shape of solder joint
is a major event in the development of electronic packaging for its practical engineering application.
In conventional electronic packages, the geometrical dimensions of solder balls and solder pads of
the package are the same. In this research, a hybrid method combined with analytical and energybased
methods is utilized to predict force-balanced heights and geometry profiles of solder balls
under various solder volume and pad dimensions as well as their relative location during the reflow
process. Next, a non-linear finite element analysis is adopted to investigate the stress/strain behavior
of solder balls in flip chip package. The results reveal that as the flip chip package contains larger
solder balls located at the corner area underneath the chip, the maximum equivalent plastic
strain/stress is evidently reduced and the reliability cycles under thermal loading are enhanced.
Furthermore, the results presented in this research can be used as a design guideline for area array
interconnections.
Thermal Deformation Analysis of Exhaust Manifold for Turbo Diesel Engine
Authors: Kim Beom Keun , Lee Eun Hye , Park Jong Sik
Published: March 2009

Thermal deformation of cast iron exhaust manifold for turbo diesel engine is investigated
by finite element analysis (FEA). The FE model includes the temperature dependent material
properties as well as the interactions between exhaust manifold, cylinder head and fasteners. It also
considers the sliding behavior of the flanges of exhaust manifold on cylinder head when either
expansion or contraction of the exhaust manifold exceeds the fastener pretension. The result of
analysis revealed that remarkable thermal deformation occurred along the longitudinal direction.
The amount of deformation was predicted and compared with experimental results. The new design
of fastener hole, which allows sliding behavior, is expected to reduce thermal stress in turbo diesel
engine exhaust manifold.
Statistical Assessment of Integrity in Steam Generator Tubes Considering Uncertainty of NDE
Authors: Lee Jae Bong , Park Jai Hak , Kim Hong Deok , Chung Han Sub , Kim Tae Ryong
Published: March 2009

A statistical assessment model for structural integrity of steam generator tubes with axial
cracks at the top of the tubesheet was proposed using Monte Carlo method. In the model, a method
for estimating the number of "real cracks" from in-situ inspection (ISI) data was used. Based on the
estimated "real cracks", the number of newly detected cracks and growth of cracks during arbitrary
operating period were simulated using the Monte Carlo method. The flaw growth rate used in the
simulation was statistically calculated from the periodic in-service non-destructive inspection data.
The number of cracks, the probabilistic distribution of crack sizes at the end of next operating
interval and the probability of burst during operation were calculated from numerously repeated
simulations using the proposed model.
Analysis of Practical Dynamic Load on Bus Frame with Regularized Inverse Problem
Authors: Song Joon Hyuk , Kang Hee Yong , Kim Chai Won , Yang Sung Mo
Published: March 2009

The inverse problem to identify the load is normally based on the measurement of
frequency response transfer functions. In this paper, the dynamic response due to external load of
vehicle structure is described with inverse problem in terms of strain from experimental and
analytical response. The function of the practical dynamic load is a combination of the analytical
and experimental method with analyzed strain by quasi-static finite element analysis under unit load
and with measured strain by strain gage under driving load, respectively. The regularization
technique is adopted to alleviate the ill-posedness of the inverse problems. To examine the proposed
method, the external load applying on bus frame is identified. The load of bus is identified by the
combination of the analytical and experimental method with analyzed strains. In order to get
analytical strains, a quasi-static finite element analysis under unit load is performed. Road
simulation test is conducted to get measured strains with strain gages. The sparseness and the noise
in the measurements should be considered properly in the load identification. In this study, the
regularization method is adopted to alleviate the ill-posedness of the inverse problems. This
procedure can be used to get the transferred load to use an input data of fatigue analysis for a substructure
of which the experimental response is difficult to get directly.
A Life Assessment for Steam Turbine Rotor Subjected to Thermo-Mechanical Loading Using Inelastic Analysis
Authors: Choi Woo Sung , Fleury Eric , Song Gee Wook , Hyun Jung Seob
Published: March 2009

An important characteristic of a steam power plant is its ability to maintain reliability and
safety of the plant against frequent start-ups and load changes. Transient regimes arising during
start-ups, shut-downs and load changes give rise to unsteady temperature distribution with time in
steam turbine rotor(HP/IP), which results in non-uniform strain and stress distribution. The rapid
increase of temperature and rotational speed during starts-ups, especially, makes conditions more
severe and causes main components’ damage and reduction of life span for steam turbine. Thus
accurate knowledge of thermal and centrifugal stresses are required for the integrity and lifetime
assessment for the turbine rotor. So far, only elastic calculations are currently performed for
simplicity. However, it is well known that the materials of steam turbine rotor deform inelastically
at high temperature. Existing models proposed to describe the viscoplastic(rate-dependent) behavior
are rather elaborate and difficult to incorporate with computer simulations in the case of complex
structures. In this paper, the life assessment for steam turbine rotor was established by combining
the inelastic behavior and the finite element method. The inelastic analysis was particularly focused
on viscoplastic behavior that is simple enough to be used effectively in computer simulation and
matches the essential features of the time-dependent inelastic behavior of materials reasonably well
for cyclic loading under non-isothermal conditions. Using this study, life consumption of steam
turbine rotor can be obtained.
Reliability of Hermetic RF MEMS Wafer Level Packaging Using Au-Sn Eutectic Bonding
Authors: Wang Qian , Choa Sung Hoon , Kim Woon Bae , Hwang Jun Sik , Ham Suk Jin , Moon Chang Youl
Published: March 2009

In this paper, a low temperature hermetic wafer level packaging scheme for the RFMEMS
devices is presented. For hermetic sealing, Au-Sn multilayer metallization with a square
loop of 70 %m in width is performed. The size of the MEMS package is 1mm × 1mm × 700 %m.
The shear strength and hermeticity of the package satisfy the requirements of MIL-STD-883F. The
total insertion loss for the packaging is 0.075 dB at 2 GHz.
A Study on Maintenance Free Method for Bogie of the Freight
Authors: Hong Jai Sung , Ham Young Sam , Paik Young Nam , Lee Kyung Yup
Published: March 2009

As there are many wear parts in the bogie of freight car, the cost of maintenance is high.
Also there are many problems to change the wear plates. In case of welded structure bogie, wear
plates are attached 30 positions. Especially, the occurrence of the wear quantity at the side of axle
box is higher than any other wear plates. Wear parts needs the low wear and high strength. But the
repeated load of carbody has acted on wear parts up down direction continually, the friction force
defects at their surfaces. At present, the life of wear plates at the side of axle box is about 3~4 years.
So we need the new development of wear plate over ten years life to improve the durability and find
the new composite material for maintenance free.
Development of Accelerated Life Test Method of Pneumatic Cylinder
Authors: Kang Bo Sik , Kim H.E. , Kwon Yong Cheol , Song Chang Seop
Published: March 2009

This paper proposed a new life test method of pneumatic cylinders used in pneumatic
system, whose loads consist of working pressure, piston velocity, and working temperature. It is
expected to reduce accelerated life test time greatly in case of accelerated life test with creating
combined accelerated model of these three factors. We can determine the maximum accelerated
factor by calculating the combined accelerated factor of working pressure, piston velocity and
working temperature for various cases.
Identification of Voids and Cracks by Ultrasonic Technique
Authors: Her Shiuh Chuan , Chang Ming Chih
Published: March 2009

Ultrasonic is one of the most wide use of nondestructive evaluation technique. Voids and
cracks are the most common defects in a solid. In this investigation, the ultrasonic technique is used
to distinguish the defects between the void and crack. As an incident wave impinges on the crack tip,
the diffractive wave can be detected from various angles. The amplitude of the diffraction is
dependent on the receiving angle. For a void, the incident wave is scattered, the amplitude of the
scattering wave is also dependent on the receiving angle. By comparing the amplitudes between the
diffractive wave and the scattering wave, one is able to identify the defect of a void or a crack from
the other. In this work, 5MHz of longitudinal and shear transducers are used and placed in a variety
of incident and receiving angles to examine the difference between the void and crack. The
experimental results are validated by the theoretical calculation. In order to identify the void and
crack, it is required to have significant difference between the diffractive and scattering waves. The
range of the detecting angle, which possesses a meaningful difference between the diffractive and
scattering waves, is proposed through the numerical and experimental study to help the
identification of the void and crack.
A Study on the Effect of Gap Width on Residual Stresses of Laser-Welded Dissimilar Joints
Authors: Yang Hae Sug , Lee Byung Chai
Published: March 2009

Laser-welded parts experience high local temperatures and severe heating-cooling cycles
which lead to large local residual stresses. These stresses introduce unacceptable degradation of the
mechanical properties of a weldment. Thermo-elasto plastic analyses with 3-D FE models, as well
as experimental investigations were performed in order to predict temperature distribution and
residual stresses of ND-YAG laser-welded joints with various gap widths between the dissimilar
steel types of austenitic and precipitation-hardening stainless steel. The specimens have the shape of
a pocket to optimize the weight of the structure, which consists of a thin skin (AISI304) and a thick
skeleton (AISI630). The residual stresses at the surface of the weldments were measured using the
instrumented indentation method. The residual stresses and melt-pool zone (MPZ) profiles show
good agreement between the theoretical and experimental results. Considering the residual stresses,
the allowable gap width range of the laser-welded joints for the pocket-shaped specimen was
calculated. For a welding joint with gap widths, the longitudinal residual stress values at the yield
stress level were observed. Melt-pool zone profiles described by the underfill and penetration depth
also depend upon the gap size.
Advanced Technologies for Estimation of Nonlinear Ultrasonic Parameter
Authors: Jhang Kyung Young , Sasaki Kimio , Ha Job , Tanaka Hiroaki
Published: March 2009

This paper proposes an advanced signal processing technique for the precise estimation
of a nonlinear ultrasonic parameter, based on power spectral and bispectral analysis. The power
spectrum and bispectrum estimation of the pulse-like ultrasonic signal used in the commercial SAM
(scanning acoustic microscopy) equipment is especially considered in this study. The usefulness of
the proposed estimation is confirmed by experiments for a Newton ring with a continuous air gap
and a real semiconductor sample with local delaminations. The results show that the nonlinear
parameter obtained by the proposed method had a good correlation with the delamination.
Determination of Thermal Conductivity of Amorphous Silicon Thin Films via Non-Contacting Optical Probing
Authors: Moon Seung Jae
Published: March 2009

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using
the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a
key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during
the laser annealing process to fabricate the thin film transistors with uniform characteristics which
are used as switches in the active matrix liquid crystal displays. Since it is well known that the
physical properties are dependent on the process parameters of the thin film deposition process, the
thermal conductivity should be measured. The temperature dependence of the film complex
refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at
the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the
thin film. In-situ transmission signal is obtained during the heating process. The acquired
transmission signal is fitted with predictions obtained by coupling conductive heat transfer with
multi-layer thin film optics in the optical transmission measurement.
Application of Determination of Principal-Stress Directions by Color Phase Shifting Technique to Model Containing Isotropic Points
Authors: Pinit Pichet , Umezaki Eisaku
Published: March 2009

This paper presents an application of a new point-wise technique for unwrapping the
isoclinic parameter determined by a four-step color phase shifting. The unwrapping technique is
based on a largest region in a binary image that corresponds to a largest visible-wrapped period of
the computed isoclinic parameter. The largest region is obtained using an intersection operation
between the extended ranges of the computed isoclinic parameter. The method uses four raw
photoelastic fringe images. The technique is applied to a circular ring containing isotropic points
subjected to diametral compression. Results show the method provides the correct isoclinic
parameter in the true interval over the entire domain.
Expert-Learner Based Virtual Reality Aid with Kinesthetic Interaction for Upper Limb Rehabilitation
Authors: Park Jong Woo , Lee Seung Jin , Cheong Joo No
Published: March 2009

Conventional limb rehabilitation requires a person-to-person meeting in a same physical
place within a fixed setting. The virtual reality (VR) aid for rehabilitation therapy eliminates such
limitations by utilizing computer generated virtual environment and off-the-shelf haptic devices. In
the proposed upper limb rehabilitation system, two identical VR systems, placed one in the expert
(therapist) location and the other in the learner (patient), are connected via communication network,
enabling interactive rehabilitation training in separate places. For the effective training and
evaluation, the expert and learner’s haptic devices are synchronized in real-time with slight active
correction by human’s active visual feedback. To verify the feasibility and usability, example tests
are presented for the developed laboratory test system.
Actin-Based Spring in Horseshoe Crab Sperm
Authors: Shin Jennifer H. , Tam Barney , Song Suk Hyun
Published: March 2009

The conversion of chemical energy into mechanical forces that powers cell movements is
a ubiquitous theme across biology. Besides molecular motors such as kinesin-microtubule and
actin-myosin complexes, biological springs and ratchets can also store and release energy to rectify
motion. The acrosome reaction of horseshoe crab sperm is a simple example of a biological spring
where a 60!μm-long crystalline bundle of actin filaments, tightly cross-linked by actin bundling
protein scruin, straightens from a coiled conformation and extends from the cell to penetrate an egg
in about five seconds. To identify the basis and mechanism for this movement, we examine the
possible sources of chemical and mechanical energy and show that the stored elastic energy alone is
sufficient to drive the reaction. We also provide an estimate of the maximum force generated during
the uncoiling by stalling the bundle using an agarose gel to show the reaction produces enough
force to penetrate the egg.
A Hemodynamic Study on a Marginal Cell Depletion Layer of Blood Flow Inside a Microchannel
Authors: Park Cheol Woo , Shin Se Hyun , Kim Gyu Man , Jang Jin Hong , Gu Yoon Hee
Published: March 2009

Biological flows, especially blood flow, have attracted a great deal of attention from fluid
engineering and hemodynamic investigation fields with advances in bio-technology. The flow of
blood carries dissolved gases, nutrients, hormones, and metabolic waste through the circulatory
system in the human body. In the present study, the characteristics of blood flow inside a
microchannel are investigated by using a micro-particle image velocimetry (micro-PIV) and an
optical image processing technique. The motion of red blood cells (RBCs) was visualized with a
high-speed CCD camera. The microchannel is made of polydimethylsiloxane (PDMS) material and
a slide-glass is attached to the top. The thickness of the margin cell depletion layer is calculated
from an acquired raw image through the image processing method, with variations in microchannel
width.
Feature Evaluation and Pattern Recognition of Lower Limb Muscle EMG during Postural Balance Control
Authors: Choi Hyeon Ki , Jeong Jae Hoon , Hwang Sung Ho , Choi Hyeon Chang , Cho Won Hak
Published: March 2009

We recognized EMG signal patterns of lower limb muscles by using neural networks and
performed feature evaluation during the recovery of postural balance of human body. Surface
electrodes were attached to lower limb and EMG signals were collected during the balance recovery
process from a perturbation without permitting compensatory stepping. A waist pulling system was
used to apply transient perturbations in five horizontal directions. The EMG signals of fifty
repetitions of five motions were analyzed for ten subjects. Twenty features were extracted from
EMG signals of one event. Feature evaluation was also performed by using DB (Davies-Bouldin)
index. By using neural networks, EMG signals were classified into five categories, such as forward
perturbation, backward perturbation, lateral perturbation and two oblique perturbations. As results,
motions were recognized with mean success rates of 75 percent. With the neural networks classifier
of this study, the EMG patterns of lower limb muscles during the recovery of postural balance can
be classified with high accuracy of recognition.
Calibration of Displacement Sensors with High-Precision and Large Measurement Range Using Temporal Speckle Pattern Interferometry
Authors: Li Xi De , Yang Yan
Published: March 2009

In the present study, a real-time calibration method for micro displacement sensors is
introduced, and a calibration system is developed. SPCM, the sequence pulse counting method
previously proposed by us, is capable of automatically determining both the larger range
displacement and the performance of a sensor, such as the nonlinear error and the displacement
sensitivity within a quarter of the light source wavelength. The new calibration system consists of a
programmable motor driven platform, an out-of-plane sensitive electronic speckle pattern
interferometry (ESPI), and a sequence image acquisition system. The platform is used to provide
displacement changes of a moving component and its displacement is measured by the ESPI and
calibrated sensor synchronously. The calibration accuracy of the proposed method is in the submicrometer
level and the displacement range can be from sub-micrometer to millimeters depending
on the storage capacity of the computer and the correlation property of the interferometer. Three
capacitance-type displacement sensors have been calibrated successfully, whose displacement
ranges are –300μm to 300μm, –30μm to 30μm, and –3μm to 3μm, respectively.
Specimen Geometry Effects on Dynamic Crack Propagation
Authors: Arakawa Kazuo , Mada Toshio
Published: March 2009

Dynamic crack propagation in PMMA was studied using the method of caustics in combination
with a Cranz-Schardin type high-speed camera. Three different types of specimen geometries were employed
to achieve the crack acceleration, deceleration and re-acceleration process in one fracture event. Dynamic
stress intensity factor KID and the crack velocity were evaluated in the course of crack propagation to obtain
the relationship between KID and the velocity The effect of crack acceleration and deceleration on the KID
-velocity relations was examined.
An Evaluation of Fracture Toughness of Glass-Filled Ceramic Using Notched Specimen
Authors: Kim Jae Hoon , Kim Duck Hoi , Rho Nam Su , Lee Young Shin , Koo Song Heo , Moon Soon Il
Published: March 2009

The objective of this study is to evaluate the mechanical properties of static, quasidynamic
and dynamic fracture toughness of glass-filled ceramic as promising structural material for
a dome port cover of a ramjet engine system. Static and quasi-dynamic tests were carried out using
SEPB (Single Edge Pre-cracked Beam) specimens. Static and dynamic fracture toughness tests
were also performed using ASTM and strain gage methods with SENB (Single Edge Notched
Beam) specimens machined with various notch radii. The critical notch radius was evaluated.
Below the critical notch radius, the static fracture toughness of the SENB specimen well agreed
with that of the SEPB specimen.
Weibull Statistics as a Basis for Assessment of Ductile-Brittle Transition Behavior
Authors: Chang Yoon Suk , Lee T.R. , Choi Jae Boong , Kim Young Jin , Kim Min Chul , Lee Bong Sang
Published: March 2009

The objective of this paper is to investigate failure characteristics of SA508 carbon steel
in ductile-brittle transition temperature region. To achieve this goal, a series of finite element
analyses as well as fracture toughness tests are performed for pre-cracked V-notch specimens. An
assessment of failure probabilities is, then, carried out employing Weibull stress models with
different rank probability options. Finally, a prototype of toughness scale diagram is derived
through comparison of estimated fracture toughness data with those for compact tension specimens.
The present results can be utilized to found a basis of realistic integrity evaluation on major nuclear
components containing defect.
Estimation of the Fatigue Lifetime of Metal Rubber Isolator with Dry Friction Damping
Authors: Ao Hong Rui , Jiang Hong Yuan , Ulanov A.M.
Published: March 2009

Metal rubber (MR) sleeve isolators have been widely applied in aerospace industry. An
experimental investigation into its fatigue lifetime was conducted. The results indicate that its
performance is determined by the following factors: the relative deformation of MR sleeve
elements, the preloading of sleeve elements, friction coefficient of metal wires and vibration
amplitude. It is concluded that solid lubricates can increase the lifetime of MR isolator greatly but
lower its ability to dissipate vibrating energy.
Effect of Shot Peening on the Improvement of Durability of Bevel Gear
Authors: Cheong Seong Kyun , Lee Dong Sun , Kang Yong Soo , Lee Tae Kun , Kim Hyun Kyu
Published: March 2009

Shot peening generate compressive residual stress, which reduces repeatedly assessed
tension stress and increase fatigue life. In this paper, the fatigue characteristics are evaluated
according to shot peening condition for the real differential gear. The specimen is a straight bevel
gear which transmits rotation of engine to running wheel and it is caburized. The bending fatigue
test was done by the jig of our own making. The peening time was changed to find the best
condition for the long fatigue life time. Fractography of specimen was analyzed by SEM to detect
the location of initial crack. The experimental results show that the optimum peening condition is at
65m/s of shot ball speed and 8min of shot peening time. From the SEM image, the location of initial
defect and direction of crack propagation were found
Crack Orientation Dependence of Fatigue Behavior in Titanium Single Crystals by Thin Sheet Plain Bending
Authors: Ando Shinji , Sakamoto Takahiro , Ikejiri Yukishige , Tsushida Masayuki , Tonda Hideki
Published: March 2009

Fatigue test of titanium single crystals with different crystallographic orientations has
been carried. To investigate fatigue fracture behavior of small single crystals, plain bending
fatigue test method for thin sheet specimen was developed. One end of the sheet specimen is fixed
at a voice coil of the loudspeaker and the other end is set free. A bending mode resonance occurs
in the specimen due to forced vibration at the fixed end. In A-specimen, a notch plane and the
direction are (11 20) and [1100], respectively, the crack propagates parallel to {1100} plane and
striation-like markings are observed on the fatigue surfaces. In B-specimen with a notch of (1100)
[1120], the crack also propagates parallel to {1100} plane as similar to A-specimen. These cracks
are deduced to extend by alternating shear on two intersecting prismatic slip systems at the crack tip.
In F-specimen with a notch of (0001) [11 20], the crack propagates parallel to (0001) and some
trace of pyramidal slip was observed on the fatigue surface. As a result, S-N curves of each
specimen showed strong orientation dependence. Fatigue strength of F-specimen is higher than that
of A- and B-specimen.
Fatigue Life Evaluation for Nuclear Power Plant Using Green’s Function and Real Operating Histories
Authors: Kim J.C. , Ahn M.Y. , Chang Yoon Suk , Choi Jae Boong , Kim Young Jin , Jhung Myung Jo , Choi Young Hwan
Published: March 2009

In general, the fatigue life of major nuclear components has been evaluated based on design
codes conservatively. However, sometimes, more exact fatigue life evaluation is required for
continued operation beyond the endorsed life. The purpose of this paper is to carry out 3-D stress and
fatigue analyses reflecting full geometry as well as actual operating data. The actual operating data
acquired through a monitoring system were filtered and assessed. Then, temperature and stress
transfer Green’s functions were developed and applied to critical locations of reactor pressure vessel.
The finite element analyses results for representative design transients were verified through
comparison to reference solution and showed that the conservatism of current 2-D evaluation.
Therefore, it is anticipated that the proposed scheme adopting Green’s function and real operating
histories can be utilized for remaining life time evaluation of major components.
Characteristics of Free Form Finishing Applying V-CAM System
Authors: Lin Wei Min , Ohmori Hitoshi , Suzuki T. , Uehara Yoshihiro , Watanabe Y. , MORITA Shinya
Published: March 2009

A new CAD system, which is called Volume-CAD (VCAD) have been developed. We
carried out research and development of VCAD fabrication process based on VCAD/CAM precision
control. In this study, a developed V-CAM had been used for a polishing fundamental experiment of a
free form surface. The relationship between NC resolution and form accuracy of polished surface are
discussed.