bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano-Imprinted Ultrahigh-Density Nanopore Arrays
Authors: Kim Kyung Hoon , Lee Min Jung , Kim Chul Kyu , Woo Eun Taek , Kim Mi Hee , Kim Youn Sang , Shin Kyu Soon
Published: March 2009

Nano-structured polymer stamps were prepared from porous anodic alumina templates.
Prepolymers were poured onto the highly ordered porous anodic alumina templates, and they were
cured by UV-irradiation. Simple separation of the elastic stamp from the nanoporous aluminum oxide
leads to well replicated nano-stamps. The nanopatterns on the stamp were transferred as
ultrahigh-density nanopore arrays on various substrates which are potentially applicable to the
fabrication of ultrahigh-density metallic or semiconductor nanodot arrays for magnetic storage
devices or display devices.
Effects of Rough Surface on Contact Depth for Instrumented Microindentation Using Spherical Indenter
Authors: Kim Ju Young , Lee Jung Jun , Lee Yun Hee , Jang Jae Il , Kwon Dong Il
Published: March 2009

Surface roughness is main source of error in instrumented microindentation when it is not
negligible relative to the indentation depth. The effect of a rough surface on the results of
instrumented microindentation testing using spherical indenter was analyzed by applying the contact
depth model, which takes surface roughness into account. Improved variations in hardness and
Young’s modulus were shown for W and Ni when the results were analyzed by this rough-surface
model, while these values were underestimated with increasing surface roughness when analyzed by
the flat-surface model. The deformation state of asperities underneath spherical indenter was also
discussed.
Microstructural Evaluation and Mechanical Properties of Al2O3/ZrO2 Layered Structure with Graded Interlayers
Authors: Park Sang Hyun , Myong Sang Won , Jung Yeon-Gil , Paik Ung Yu
Published: March 2009

Layered structure with composition gradient between inner layer of alumina (Al2O3) and
outer layer of zirconia ( ZrO2-3mol% Y2O3 ;TZ-3Y) was fabricated using a gel casting process for the
inner layer and a dip coating process for the outer layer in an aqueous system. The interlayer with
composition gradient was prepared by mixing the Al2O3 and TZ-3Y slips as a volume ratio. Dried
green bodies of the inner layer were pre-sintered at 1100°C for 5hr. After pre-wetting the pre-sintered
bodies, the dip coating was preformed with mixed slips. Two kinds of composition gradients in the
interlayer were prepared to observe the effect of composition gradient on mechanical properties, with
same thickness. One is continuous composition gradient from Al2O3 to TZ-3Y with 9:1 to 1:9 volume
ratios, and the other is layered structure with 8:2, 6:4, 4:6, and 2:8 volume ratios of Al2O3 and TZ-3Y.
After the dip coating with each mixed slip, the coated bodies were sintered at 1100°C for 1hr to
prevent delamination between each layer. The last dip coating was performed with the TZ-3Y slip,
and then sintered at 1600°C for 3hr. Microstructure and element analysis of the sintered bodies were
observed using SEM. For measurement of flexural strength, a standard four-point banding test was
conducted. Also, hardness and modulus were measured using micro- and nano-indentation techniques.
The step-like gradient in microstructure and composition is achieved through the gel casting and dip
coating processes, including a gradual change in H and E from the inner to outer layers.
Tensile Properties of Friction Stir Welded AZ31B Mg Alloy
Authors: Ha Seon Mi , Kim Sang Shik , Chang Dong Yim , Lee Chang Gil , Kim Sung Joon
Published: March 2009

The effect of prior T4 heat treatment and subsequent microstructural evolution on tensile
behavior of friction stir welded (FSWed) AZ31B-H24 alloy was examined in this study. Selected
AZ31B-H24 plates were prior T4 heat treated at 400 for 24 hours and subsequently friction stir
welded. The tensile properties, optical micrographs and SEM fractographs for FSWed AZ31B-T4
specimens were compared with those for the H24 counterparts. Prior T4 heat treatment tended to
decrease the tensile ductility reduction in FSWed AZ31B-H24 specimen. The tensile ductility
reduction mechanism as associated with prior T4 heat treatment is discussed based on detailed
micrographic and fractographic observations.
Influence of Thixoextrusion Parameters on Mechanical Properties of Thixoextruded 7075 Al Wrought Alloy
Authors: Yoon Young Ok , Kim Shae K.
Published: March 2009

The main emphasis of this study is to utilize thixoextrusion process for improving
extrudability of 7075 Al wrought alloy. In the present study, the influences of thixoextrusion
parameters, such as initial ram speed and die bearing length, on mechanical properties of
thixoextruded 7075 Al wrought alloy were investigated. The results of thixoextrusion experiments
about microstructures and mechanical properties were compared with conventional extrusion results.
The maximum extrusion pressure of thixoextrusion processes was seven times lower than that of
conventional hot extrusion processes. The hot extruded bars show a large amount of grains which are
stretched along the extrusion direction and asymmetry of grains was formed to extrusion direction,
while the microstructures of the thixoextruded bar did not show any asymmetry and grains were
homogeneously distributed. The hardness values of thixoextruded bar were higher than that of
conventional hot extruded bar.
Fatigue Behavior of Thin Cu Foils for Flexible Printed Circuit Board
Authors: Han Seung Woo , Seo Ki Jeong , Kim Wan Doo , Lee Hak Joo , Lee Hyun Woo , Shin Jae Ho , Lee Jae Joon
Published: March 2009

Flexible printed circuit board (PCB), which is used for folder and slide type cellular
phones, consists of flexible copper clad laminate (FCCL) and cover layer. Through it an electric
current is applied to liquid crystal display (LCD) from the main board of cellular phone. In thin Cu
foils of flexible PCB fatigue cracks due to repeated bending motion generate and propagate, and they
cause a short circuit. Fatigue behavior of thin Cu foils being used for flexible PCB must be evaluated
and confirmed to resolve this problem. It is based on findings by several researches that the
mechanical properties of thin film materials differ from those of their bulk counterparts. Thin film
properties have been investigated over the last years; however fatigue behavior of thin films has not
yet been studied as thoroughly as monotonic behavior. In this study fatigue properties of thin Cu foils
for the application in flexible PCB are obtained. Fatigue testing was performed for two kinds of Cu
foils that were made by rolling and electrochemical procedures respectively. Differences of
fabrications in fatigue behavior of thin foils were distinguished. Especially for rolled Cu foils, effects
of rolling directions in fatigue properties were evaluated.
Solid State Diffusion Bonding of Titanium Alloys
Authors: Lee Ho Sung , Yoon Jong Hoon , Yi Yeong Moo
Published: March 2009

Solid State diffusion bonding is obtained by applying heat, well below the melting
temperature of the metals, a static pressure which does not cause a macroscopic plastic deformation in
the material, and a time required to form a metallurgical bond with atomic diffusion process. This
process is used for aluminum alloys, high strength steels and titanium alloys in the aerospace industry
to produce complex and inaccessible joints without localized distortion. Ability to diffusion bond
titanium alloys is strongly needed to promote the use of superplastic forming technology. In the
present work, the solid state diffusion bonding was carried out using specimens in Ti-6Al-4V and
Ti-15V-3Cr-3Sn-3Al. The microstructure of the bonded interface indicates the diffusion bonding
process is successful for both alloys. It is also shown that the diffusion bonding of a superplastic
Ti-6Al-4V alloy is possible at the optimum superplastic condition so that two processes can be
performed simultaneously. The structural integrity of diffusion bonding was evaluated with a
hydraulic test of diffusion bonded part.
Embossing Lithography on Sticky Thermoset Polymer Using Ni Template
Authors: Byeon Kyeong Jae , Hong Sung Hoon , Yang Ki Yeon , Ra Seung Hyun , Ahn Jin Ho , Lee Heon
Published: March 2009

Embossing lithography is one of the most promising technologies for mass production of
nano-scale structures. To advance the industrialization of embossing lithography, fabrication of low
cost, high mechanical strength embossing template is essential. Electroformed Ni template can be
used as an embossing template if its poor anti-adhesive property is fixed by proper releasing layer
treatment, especially, when it is used with sticky thermoset polymer.
In this experiment, quartz master template with 200nm to 2um sized surface protrusions was
fabricated and used to emboss the PMMA coated Si wafer. Then the embossed PMMA layer was
coated with metal seed layer (Ni) and electroplating of Ni was followed to fabricate Ni template.
To apply anti-stiction SAM layer, SiO2 and Si layer was coated on Ni template. With proper
anti-stiction treatment of Ni template, sub-micron patterns were successfully transferred to sticky
thermoset polymers such as epoxy resin using Ni template without any degradation of anti-adhesive
property.
Formation of Ferrite with Cr Equivalents and Solidification Rates in Mod. (9-12)Cr-1Mo Steels
Authors: Kim Y.H. , Kim H.C. , Jung Yeon-Gil , Lee J.H. , Chi B.H. , Ryu S.H.
Published: March 2009

The influence of solidification rates and Cr equivalents on the formation of the ferrite was
studied by directional solidification in mod. (9-12)Cr-1Mo steels. It was found that the volume
fraction of ferrite increased as increasing Cr equivalent and solidification rate. The volume fraction of
the ferrite showed much higher at low solidification rates with the planar or cellular interface than that
at high solidification rates with the dendritic interface. The volume fraction of ferrite in solidification
microstructure showed much higher than that in extruded and heat-treated alloys. It depends on not
only solidification rate and Cr equivalent but also the solidification fraction. At low solidification
rates, there occurs segregation because the solid/liquid interface was planar or cellular, and it makes
composition change with solidification fractions. The formation of ferrite has been discussed with Cr
equivalent and solidification rate.
MC Carbide Decomposition during Thermal Exposure of Polycrystalline Ni-Base Superalloys
Authors: Choi Baig Gyu , Kim In Soo , Kim Doo Hyun , Jo Chang Yong
Published: March 2009

MC decompositions during thermal exposure have been investigated in three conventional
cast Ni-base superalloys, GTD111, IN738LC, and CM247LC. MC decomposition in GTD111 and
IN738LC depends on exposure temperature. While MC decomposed into M23C6 at 982°C, η formed
from MC after exposure at 927°C and 871°C. Ta and Ti separated from MC during thermal exposure
made η phase to form instead of γ'. The decomposition of the MC in CM247LC depends on their
morphology and position. Segregation during casting process affected the morphology and
composition of MC type carbide in this alloy. Acicular M6C was found near scriptal MC in the
dendrite. Blocky MC near γ-γ' eutectic decomposed into M23C6. Both M23C6 and M6C can be found
on grain boundary after thermal exposure in CM247LC.
Effect of Heat Treatment on Characterizations of TiCrN Coated Layer by R.F Magnetron Sputtering
Authors: Song Dong Hwan , Yang Gon Seung , Lee Jong Kook
Published: March 2009

Series of TiCrN wear resistant coatings have been known to be superior to other coatings in
protecting tools which may be damaged corrosion, oxidization, abrasion and hardness of mold
materials. The corrosion and oxidation resistance of TiN/CrN(TiCrN) multilayer coatings is better
than that of single TiN and CrN coatings. TiCrN coated layer was formed by coating a layer of
TixCr1-xN by non-stoichiometry. In this study, TiCrN coated layer by R.F magnetron sputtering was
executed heat treatment each other temperature by tube furnace. And then surfaces of coated layer
and cross sections were observed by FE-SEM and XRD. Corrosion resistance tester measured
characterizations of coated layers. When the temperature increased, TiN was partially transformed to
Ti2N and TiNX, and CrN was also transformed to Cr2N. The formation of non-stoichiometric phases
decreased corrosion resistance.
Effect of Delta Ferrite on Corrosion Resistance of Type 316L Stainless Steel in Acidic Chloride Solution by Micro-Droplet Cell
Authors: Kim Sung Yu , Kwon Hyuk Sang , Kim Hee San
Published: March 2009

More than 2% δ-ferrite phase is presented in type 316L stainless steels due to improvement
of hot workability or welding process. In order to clarify the mechanism on how the δ-ferrite affects
the corrosion resistance, electrochemical tests in a micro-droplet cell were conducted and
microstructures were analyzed by TEM-EDS and SEM-EDS. Especially, the micro-droplet cell was
modified at our laboratory to observe the polarization behavior of δ-ferrite phase in an acidic chloride
solution. The anodic polarization behavior in both active zone and passive zone was affected by
δ-ferrite. The degradation of corrosion resistance in the low potential zone with δ-ferrite phase is due
to the preferential dissolution of a matrix, γ phase. It is explained with the fact that the formation of
δ-ferrite lowers the concentrations of chromium and molybdenum in γ phase. It is also confirmed by
potentiostatic test, EDS analyses and phase-equilibrium prediction. In addition, the micro-droplet cell
and EDS analysis reveled that the pitting potential in the neutral pH solution was affected by Ca
containing inclusion rather than δ-ferrite phase.
Influences of Si, W, and Cu on the Localized and Stress Corrosion of 18 % Cr Austenitic Stainless Steel
Authors: Kim Deog Ryung , Park Chan Jin
Published: March 2009

Effects of Si, W and Cu on the localized and stress corrosion of 18 % Cr austenitic stainless
steel were investigated using experimetal strategy of full factorial design. The resistance to localized
and stress corrosion of the alloy was improved with increasing the contents of Si, W and Cu in the
range of 0.5 ~ 1.5 % for Si, 0.1 ~ 0.5 % for W and 0.2 ~ 2.0 % for Cu. In addition, we found an
interaction effect between Si and Cu on the reistance to localized and stress corrosion of the alloy.
The Sliding Wear Behavior of Titanium Carbide Dispersion-Reinforced Steel
Authors: Lee Jeong Keun
Published: March 2009

The tribological behavior of TiC-based metal matrix composites was investigated via
measuring counterpart weight. The composites were prepared using powder metallurgy technique.
Wear of counterpart by the composites varying from 35 to 45 % by volume Titanium carbide were
observed over a load ranges of 9.81 to 49.05 N and sliding velocities of 2.0, 2.2, 2.4, 2.6, 2.8 and
3.0 m/sec. Detailed wear track micro-graphy was done to verify the effect of sliding condition on
wear mechanism. Observations indicate that wear rate of counterpart increases with the increase in
load and the sliding velocity and discontinuous wear rate change occurs at a certain load.
Variation of Corrosion Resistance and Hardness with Heat Treatment of ALDC8 Al Alloy
Authors: Moon Kyung Man , Lee Myeong Hoon , Kim Ki Joon
Published: March 2009

ALDC8 alloy was often corroded with form of intergranular corrosion in corrosive
environments. Thus in order to improve its corrosion, the effect of annealing to corrosion resistance
and hardness was investigated with parameters of heating temperatures such as 100°C, 200°C,
300°C, 400°C and 500°C for 1hr. Hardness was slightly decreased with annealing, especially, the
decreasing of hardness was remarkably revealed in annealing temperature at 300°C. Corrosion
potential was shifted to noble direction, and both AC impedance at 10m㎐ and polarization resistance
on the cyclic voltammogram was also increased with annealing. Intergranular corrosion was not
nearly observed at annealing temperature of 400°C, 500°C. Therefore the optimum annealing
temperature for corrosion resistance as well as mechanical property is thought to be 400°C or 500°C.
Shielding Effectiveness Simulation of Brass-Iron Sandwich Films
Authors: Zhang Xiao Ning , Wang Qing
Published: March 2009

This paper presents a simulation method on shielding effectiveness(SE). The method is
completely general and able to optimize shielding materials. We found a sandwich structure that it can
efficiently shield plane wave, using this simulation method. The relationship of film thickness and its
skin depth was investigated in this study. Two-dimensional curves and three-dimensional graphs were
calculated by tri-layer SE formulas. A sandwich structure, which is 3μm iron-brass-iron films, is
capable of excellent shielding properties: the SE is between -73dB and -100dB in the frequency range
of 1MHz~10MHz. Another sandwich structure with 12μm thickness of brass-iron-brass films can
offer -680dB shielding attenuation. Simulation experiments indicate that sandwich films with
diamagnetic and ferromagnetic layers have outstanding contribution on SE.
Microscratch Analysis and Interfacial Toughness of Catalyst Coating on Electrolyte Polymer in Micro Fuel Cells
Authors: Lee Gyu Jei , Lee Han Kyu , Kwon Dong Il
Published: March 2009

This study combined microscratch test and fracture-mechanical analysis to assess the
interfacial reliability of Nafion and Pt/Ru catalyst layers in micro fuel cells. Scratch test was used to
determine the critical load for interfacial failure, while fracture-mechanical analysis was used to
quantify the adhesion between Nafion (the electrolyte polymer substrate) and Pt/Ru alloy (catalyst
coating). We also proposed a key of solving ambiguous problems in indentation cracking test by
determining geometric information from crack propagation and critical points, as for a hard porous
coating on a soft substrate. A comparative analysis of three coating methods, spray, decalcomania
and their mixed process, was done to assess the validity of our new method.
EXAFS Analyses on Local Structure of Gallium in Amorphous Selenide Optical Materials Doped with Rare Earths
Authors: Choi Yong Gyu
Published: March 2009

Ga K-edge EXAFS spectra have been analyzed to elucidate the local coordination structure
of Ga in two representative selenide Ge-As-Se and Ge-Sb-Se glasses all doped with Pr. Gallium
turned out to be coordinated with 4 Se atoms in its first neighboring shell. This implies that Ga does
not follow the 8-N rule associated with the short-range order structures of typical covalent glasses,
further indicating there being more ionic-bond nature in the Ga-Se bonds compared to other
heteropolar chemical bonds in the selenide glasses. This is decisive for the Pr3+ ions to be
incorporated in the selenide glasses. In this case, the GaSe4 units can be electrically neutralized by the
doped Pr3+ ions that act as a charge compensator. As such, inside the selenide glasses, distributions of
Pr3+ ions and the Ga tetrahedral units are closely correlated. Spectroscopic properties of rare earths
embedded in these Ga-containing selenide glasses thus can be explained in connection with the
proposed role of Ga.
Observation of an Interlayer in a Nano-Scale SiO2 Layer on Si Substrate by X-Ray Reflectivity (XRR) Analysis
Authors: Kim Chang Soo , Koo Tae Kyoung , Choi Young Dae
Published: March 2009

In the study, an interlayer was observed in a nano-meter scale SiO2 overlayer on Si
substrate by X-ray reflectivity(XRR) analysis and a new method is introduced for the XRR
analysis of SiO2 ultra-thin films on Si substrate. The normalized reflectivity curves were analyzed
by fitting with the calculated reflectivity curves which were also normalized with the same
reference curves. The XRR analyses show that the variation of the positions of the thickness
fringes in the measured reflectivity curve is caused by the interference effect from two oxide layers
of different refractive indices and of different thicknesses with each other. The result indicates that
there exists a SiO2 interlayer of a different refractive index between the SiO2 overlayer and the Si
substrate. The analytical method used in the study determines the thickness of a ultra-thin SiO2
layer on Si with low uncertainty.
Electrical Properties of Lead Zinc Niobate - Lead Zirconate Titanate Thick Films Formed by Aerosol Deposition Process
Authors: Choi Jong Jin , Jang Joo Hee , Park Dong Soo , Hahn Byung Dong , Yoon Woon Ha , Park Chan
Published: March 2009

Lead zinc niobate (PZN) added lead zirconate titanate (PZT) thick films with thickness of
5~10 μm were fabricated on silicon and sapphire substrates using aerosol deposition method. The
contents of PZN were varied from 0, 20 and 40 %. The as deposited film had fairly dense
microstructure without any crack, and showed only a perovskite single phase formed with nano-sized
grains. The as-deposited films on silicon were annealed at temperatures of 700oC, and the films
deposited on sapphire were annealed at 900oC in the electrical furnace. The effects of PZN addition
on the microstructural evolution were observed using FE-SEM and HR-TEM, and dielectric and
ferroelectric properties of the films were characterized using impedance analyzer and Sawyer-Tower
circuit, respectively. The PZN added PZT film showed poor electrical properties than pure PZT film
when the films were coated on silicon substrate and annealed at 700oC, on the other hand, the PZN
added PZT film showed higher remanent polarization and dielectric constant values then pure PZT
film when the films were coated on sapphire and annealed at 900oC. The ferroelectric and dielectric
characteristics of 20% PZN added PZT films annealed at 900oC were comparable with the values
obtained from bulk ceramic specimen with same composition sintered at 1200oC.
Effect of Curvature on Gas-Particle Flow in Converging and Diverging Supersonic Nozzle
Authors: Park Sung Han , Han Jeong Whan , Lee Chang Hee , Kim Hyung Jun
Published: March 2009

A cold spray process is a relatively new process using high velocity metallic particles
for surface modifications. Metallic powder particles which are injected into a converging-diverging
nozzle are accelerated to supersonic velocities. In this study a comparative study was performed to
figure out the effect of curvature on gas and particle flow in converging-diverging nozzle. And, the
critical radius of curvature in converging and diverging section of nozzle and the behavior of the gas
and particle flow were determined and calculated, respectively.
Estimation for Nd-Fe-B Melt-Spun Powder Quality
Authors: Tu L.T. , Vuong N.V. , Hieu N.T. , Kim Cheol Gi , Kim Chong Oh
Published: March 2009

The squareness factor γ used to evaluates for criterion allowing quick estimation of the
quality of NdFeB melt-spun powders on Stoner–Wohlfarth model. For the powder compaction of
6.4 g/cm3 mass density, the measured value γ=0.48 serves the evidence of the Stoner – Wohlfarth
behaviour of the powder grains and the preparation conditions are optimal for producing Stoner –
Wohlfarth particles. For the powder compaction of given mass densities the calibration curve of
the squareness factor γ is presented. We can observe one more thing that for the ideal, full dense
compaction of NdFeB Stoner – Wohlfarth particle the squareness factor γ can not be large than
0.53.
Preparation and Stabilization of Chitosan-Lipase Composite within Mesoporous Silica Material
Authors: Kwon Sun Sang , Jeon Sang Hoon , Shon Jeong Kuk , Kim Duck Hee , Chang Ih Seop , Kim Ji Man
Published: March 2009

To improve lipase activity and make the particulate carrier for practical application, lipase
was conjugated to chitosan(Mwavg=80,000) by immine reaction. The lipase activity of conjugate was
93% of its initial activity at room temperature for 7 months, whereas the intact lipase activity
decreased to 40%. And then, lipase-chitosan conjugate was intercalated within porous silica. The
composite was characterized by X-ray diffraction, scanning electron microscopy, thermo gravimetric
analysis. The Pore size was regulated in the range of 5~15nm. The maximum enzyme activity of
lipase-chitosan conjugate needs the structure with 15nm pore of mesoporous silica. The resultant
composite was found to have the free flowing property and keep up inner lipase activity.
Nano-Sized Au/CeO2 Catalysts for Total and Selective CO Oxidation
Authors: Ko Eun Yong , Park Eun Duck , Lee Hyun Chul , Lee Doo Hwan , Kim Soon Ho
Published: March 2009

Au/CeO2 catalysts prepared by a deposition-precipitation and a co-precipitation method
were applied to CO oxidation in the absence and presence of hydrogen. The transmission electron
microscope (TEM), the temperature programmed reduction (TPR), and the X-ray absorption near
edge structure (XANES) were conducted to probe structural and electronic properties of gold. Au2O3
was determined to be mainly present when Au/CeO2 was prepared by a deposition-precipitation
method. However, the metallic gold was observed in a co-precipitated Au/CeO2 catalyst. Au/CeO2
containing oxidized gold species, prepared by a deposition-precipitation method, showed the
decreasing CO conversion with a reaction time, which accompanied the reduction of gold from
Au(+3) to Au(0). However, co-precipitated Au/CeO2 showed the stable CO conversion. The effect of
pretreatment condition on CO oxidation was also examined. These results support that Au/CeO2
catalyst containing oxidized gold species was superior to Au/CeO2 catalyst containing the metallic
gold for CO oxidation. This Au/CeO2 catalyst was also active for the selective CO oxidation in the
presence of hydrogen.
Synthesis and Catalytic Application of Mesoporous Molecular Sieves MCM-41 Containing Niobium and Tantalum
Authors: Jung Hun , Jung Kwang Deog , Joo Oh Shim , Kim Sun Jin
Published: March 2009

Niobium- and tantalum-containing mesoporous molecular sieves MCM-41 have been
synthesized, and applied as a catalyst for vapor phase Beckmann rearrangement of cyclohexanone
oxime to ε-caprolactam. NbMCM-41 catalyst exhibited high catalytic performance in the vapor
phase Beckmann rearrangement of cyclohexanone oxime. The oxime conversions were almost
100% and the lactam selectivities were around 80%. The lactam selectivities of NbMCM-41
catalyst were higher than those of AlMCM-41 catalyst. However, TaMCM-41 catalyst exhibited
lower catalytic performance than AlMCM-41 catalyst, and it was fast deactivated with time. These
results may be due to the acidity difference among the catalysts. The results from NH3-TPD showed
that NbMCM-41 catalyst possessed weak and medium acid sites, while TaMCM-41 catalyst
possessed only very weak acid sites. AlMCM-41 catalyst also exhibited only weak acid sites.
Influence of Electrolytic Mediums on Microstructure of Anodic Titania Film
Authors: Oh Han Jun , Lee Jong Ho , Jeong Yong Soo , Ki Beom Su , Heo Chang Hoe , Kwon So Hyun , Chi Choong Soo
Published: March 2009

Surface characteristics of anodic titania formed by electrochemical method and effects of
electrolytic mediums on microstructures of anodic TiO2 layer were investigated. The titania film
formed in sulfuric acid or mixture electrolyte with sulfuric and phosphoric acids shows porous cell
structures. But the films formed in sulfuric acid represent smaller cell structures than those formed in
the mixture electrolyte, and the change in microstructural parameters is associated with electrolytes.
However, when titanium substrate was anodized in HF, surface morphologies and structures of
anodic titania film greatly changed, forming self-organized TiO2 nanotubes.
Ti Oxide Films Formed by an Anodizing Process for Use in Dental Implants
Authors: Lee Ji Eon , Kim Kye Sung , Cho Young Rae , Kim Kwang Ho , Chung Won Sub
Published: March 2009

Anodic oxide films were formed on titanium using an electrolyte solution containing
phosphoric acid for dental implants by an electrochemical method. The parameters of the oxidation
process were current density and electrolyte concentration. The micro structural morphology,
surface roughness, thickness of the oxide layer and the behavior of voltage-time curves were
examined. The results show that the surface roughness, porosity size and the thickness of the oxide
layer showed similar trends as the process parameters were changed. The surface morphology of the
samples was observed for different current densities at a constant electrolyte concentration. The
pore size, thickness and roughness of the anodic oxide films are directly proportional to the
maximum voltage and the slope of the voltage to time transient (dV/dt) curves during the growth of
the galvanostatic anode oxide film on plate type Ti.
Characterization and Acid Catalytic Properties of NiO Supported on ZrO2 and Modified with MoO3
Authors: Sohn Jong Rack , Shin Dong Cheol
Published: March 2009

Nickel oxide supported on zirconia and modified with MoO3 for acid catalysis was
prepared by drying powdered Ni(OH)2-Zr(OH)4 with ammonium heptamolybdate aqueous solution,
followed by calcining in air at high temperature. The characterization of prepared catalysts was
performed using FTIR, Raman, XRD, and DSC. MoO3 equal to or less than 15 wt% was dispersed on
the surface of catalyst as two-dimensional polymolybdate or monomolybdate, while for MoO3 above
15 wt%, crystalline orthorhombic phase of MoO3 was formed. The high acid strength and acidity were
responsible for the Mo=O bond nature of the complex formed by the interaction between MoO3 and
ZrO2. The catalytic activity for cumene dealkylation was correlated with the acidity of the catalyst
measured by the ammonia chemisorption method
Dry Wear Properties of Porous Copper Fabricated by Unidirectional Solidification
Authors: Um Yong Su , Nakajima Hideo , Seong Hwan Goo , Hur Bo Young
Published: March 2009

We have been investigated application of the lotus type porous metal that is
manufactured by the unidirectional solidification of the melt in pressurized gas atmosphere such as
hydrogen or nitrogen for an air bearing development. In this study, wear properties of porous copper
having cylindrical pores have been investigated. Generally, wear test is influenced by a shape, a wear
test method, atmosphere and a way of lubrication. Wear test used pin on disk type's wear test.
A Study on Al-Mg Alloy Foams by Melt Foaming Method
Authors: Song Yeong Hwan , Park Soo Han , Kim Sang Youl , Seo Chang Hwan , Hur Bo Young
Published: March 2009

Al-Mg alloy foams were synthesized via conventional melt foaming method. Ca and TiH2 were
introduced into molten Al-Mg alloys with different magnesium contents. The macrostructures of
resultant alloy foams were analyzed and correlated with compressive properties estimated by
compression test. It is shown that the pore structures observed in alloy foams degraded with
increasing Mg contents. This tendency was shown to be consistent with compressive
characteristics of corresponding alloy foams. In detail, plateau strength was high for Al-1wt%Mg
alloy foams, exhibiting a gradual decrease in plateau strength with increasing magnesium content.
Effects of CeO2 on the Piezoelectric Properties of PSN-PMN-PZT Composition under Various Alternating Electric Fields
Authors: Yoon Man Soon , Yi Seung Hwan , Choi Y.G. , Kwon Joon Chul , Lee K.S. , Heo S.M. , Ur Soon Chul
Published: March 2009

0.03Pb(Sb0.5Nb0.5)O3-0.03Pb(Mn1/3Nb2/3)O3-(0.94-x)PbTiO3-xPbZrO3 ceramics doped with CeO2
were synthesized by conventional bulk ceramic processing technique. Phases analysis, microstructures and
piezoelectric properties were investigated as a function of CeO2 contents (0.03, 0.05, 0.1 0.3, 0.5 and
0.7wt%). Microstructures and phases information were characterized using a scanning electron microscope
(SEM) and an X-ray diffractometer (XRD). Relative dielectric constant (K33
T) and coupling factor (kp) were
obtained from the resonance measurement method. Both K33
T and kp were shown to reach to the maximum at
0.1wt% CeO2. In order to evaluate the stability of resonance frequency and effective electromechanical
coupling factor (Keff) as a function of CeO2 addition under strong electric field, the variation of resonance
and anti-resonance frequency were also measured using a high voltage frequency response
analyzer(FRA5096) under various alternating electric fields from 10V/mm to 80V/mm. It was shown that
effective electromechanical coupling factor was increased by increasing the CeO2 additions.
Characteristics of SiO2 Film Grown by Atomic Layer Deposition as the Gate Insulator of Low-Temperature Polysilicon Thin-Film Transistors
Authors: Lee Won Jun , Chun Min Ho , Cheong Kwang Su , Park Kwang Chol , Park Chong Ook , Cao Guo Zhong , Rha Sa Kyun
Published: March 2009

SiO2 films were prepared by atomic layer deposition (ALD) technique, and their physical
and electrical properties were characterized for being applied as a gate insulator of low-temperature
polysilicon thin-film transistors. ALD SiO2 films were deposited at 350–400 oC using alternating
exposures of SiH2Cl2 and O3/O2, and the characteristics of the deposited films were improved with
increasing deposition temperature. The ALD films deposited at 400 oC exhibited integrity, surface
roughness and leakage current better than those of the conventional plasma-enhanced chemical vapor
deposition (PECVD) films.
Study on Light Induced Leakage Current Related to Amorphous Silicon TFT Design
Authors: Jeon Jae Hong , Lee Kang Woong
Published: March 2009

We investigated the effect of amorphous silicon pattern design regarding to light induced
leakage current in amorphous silicon thin film transistor. In addition to conventional design, where
amorphous silicon layer is protruding outside the gate electrode, we designed and fabricated
amorphous silicon thin film transistors in another two types of bottom gated structure. The one is that
the amorphous silicon layer is located completely inside the gate electrode and the other is that the
amorphous silicon layer is protruding outside the gate electrode but covered completely by the source
and drain electrode. Measurement of the light induced leakage current caused by backlight revealed
that the design where the amorphous silicon is located inside the gate electrode was the most effective
however the last design was also effective in reducing the leakage current about one order lower than
that of the conventional design.
Characteristics of Inductive Coupled Plasma with Internal Linear Antenna Using Multi-Polar Magnetic Field for FPD Processing
Authors: Lim Jong Hyeuk , Kim Kyong Nam , Yeom Geun Young
Published: March 2009

An internal linear inductive antenna referred to as “double comb-type antenna” was used
for a large-area plasma source with the substrate area of 880mm × 660mm and the effects of
multi-polar magnetic field applied by inserting permanent magnets parallel to the linear internal
antennas on the plasma characteristics were investigated. By applying the multi-polar magnetic field,
high density plasmas on the order of 3.2 × 1011-3 which is 50% higher than that obtained for the
source without multi-polar magnetic field could be obtained at the RF power of 5000W. Also stable
impedance matching with a low Q-factor of the plasma system could be obtained. The application of
the multi-polar magnetic field not only increased the plasma density but also improved the plasma
uniformity (less than 3%) within the 880mm × 660mm processing area.
Heartbeat Monitoring Technique Based on Corona-Poled PVDF Film Sensor for Smart Apparel Application
Authors: Chang You Min , Lee Jong Soon , Kim Kap Jin
Published: March 2009

Flexible piezoelectric polymer materials for smart apparel and wearable computer
applications are of great interest. Among known ferroelectric and piezoelectric polymers,
polyvinylidene fluoride (PVDF) exhibit β-phase under poling and is known to give highest piezo-,
pyro-, and ferroelectric properties. Previous reports suggests that, during corona poling of the PVDF
film, a high surface electric potential is generated resulting in a high internal electric field within the
polymer film causing the polarization of the dipoles along the direction of the applied electric field.
The resultant phase change from α- to β-phase and the dipole switching generates displacement of
charges or piezoelectricity. And also mechanical variation would change dipole density of PVDF
film. In this report, we measured human heartbeat signal from an DAQ interfaced with a custommade
voltage-amplifier with specific frequency filtering function using the corona-poled PVDF
film of various sizes and thickness as a piezoelectric sensor and analyzed it. We employed elastic
textile band to sensor system for comfortable fit on wrist or ankle. And then, we found the
feasibility of applying flexible PVDF film sensor to smart apparel application which can sense
heartbeat rate, blood pressure, respiration rate, accidental external impact on human body, etc.
Electrical and Electrochromic Characterization of Poly (ethylene-oxide)/V2O5 Xerogel Films
Authors: Jin Ai Ping , Zhu Quan Yao , Chen Wen , Volkov Victor L. , Zakharova Galina S. , Liu Han Xing , Zhou Jian , Xu Qing
Published: March 2009

Vanadium pentoxide xerogel films intercalated by poly (ethylene oxide), PEO, were
prepared using direct intercalation method via a sol-gel route. The electrical and electrochromic
characterization of the films were conducted. The electrical properties along and across V-O layers
have been evaluated. The results indicate that the proper amount of PEO can increase the electrical
conductivity and charge density of the films. The electrochromism of the films upon lithium
intercalation was investigated by ex-situ transmittance measurement. The films display a reversible
multichromism (orange green blue) upon Li+ ion insertion/extraction.
Interface Reaction between Fillers and Phosphate Glass for Barrier Ribs in Plasma Display Panel
Authors: Chong Eugene , Jeon Jae Sam , Sung Woo Kyung , Kim Hyung Sun
Published: March 2009

The present study is mainly focused on the evaluation of interface reaction between
ceramic fillers and phosphate glass matrix for barrier ribs in PDP. The samples were prepared by dry
milling for frits with a mean particle size(d50) of 1-2㎛. The frit was mixed with ceramic fillers (Al2O3,
ZnO) and was fired at 550°C for 30 minutes. Interface reaction was observed by measuring the
weight change of fired samples as a function of immersion time in 90°C de-ionized water and in 60°C
acid solution. Fired samples were characterized by differential thermal analyzer, scanning electron
microscopy, X-ray diffraction and ion dissolution was analyzed by inductive coupled plasma
measurement. The results suggest that properties of barrier rib depend on the crystallization behavior
and interface reaction between the fillers and the glass matrix.
Molecular Ordering and the Current-Voltage Characteristics of m-MTDATA Thin Films
Authors: Oh Seong , Kang Do Soon , Park Dae Won , Choe Young Son
Published: March 2009

Molecular ordering and current-voltage characteristics of vacuum-deposited
m-MTDATA(4,4’,4’’-tris[N,-(3-methylphenyl)-N-phenylamino]triphenylamine), widely used as a
hole injection material in OLEDs, thin films were investigated. Molecular ordering was induced by
thermal annealing under electromagnetic field after deposition of m-MTDATA onto the pre-patterned
ITO glass. AFM and XRD analysis were employed to characterize the topology and molecular
ordering of m-MTDATA thin films. The XRD and AFM results show that m-MTDATA can be
molecularly ordered by means of thermal annealing under electromagnetic field. Thermal annealing at
100°C was desirable to get a high degree of molecular ordering with dendritic grains. It was shown
that molecular ordering as well as larger dendritic grains in the thin films influenced on improving the
current-voltage characteristics and increasing the leakage current of the ITO/m-MTDATA/Al device.
Electromagnetic field improved the surface roughness, as well. It is regarded that Rpv seems more
significant than the other roughness parameters. Significantly lower Rpv(peak-to-valley roughness)
obtained by both thermal annealing and electromagnetic field resulted in enhancing the stability of the
current ITO/m-MTDATA/Al device. Ra(average roughness) and Rrms(root-mean-square roughness),
however, did not significantly relate with leakage current.
Uniform Poly-Si TFTs for AMOLEDs Using Field-Enhanced Rapid Thermal Annealing
Authors: Kim Hyoung June
Published: March 2009

Polycrystalline Si thin film transistors (TFTs) have been fabricated through solid phase
crystallization using field-enhanced rapid thermal annealing (FE-RTA) system. The system consists of inline
furnace modules for preheating and cooling of the glass substrates and a process module for rapid radiative
heating combined with alternating magnetic field induction. The FE-RTA system enables crystallization of
amorphous Si at high throughputs without any glass damages. While the typical grain structures of poly-Si by
FE-RTA are similar to those of solid phase crystallization, the residual amorphous Si and intragranular defects
are reduced.
Investigation of Thermal Measurement Variables in High Power GaN-Based LEDs
Authors: Yang Lian Qiao , Hu Jian Zheng , Shin Moo Whan
Published: March 2009

In this paper we report on the effects of variables in thermal resistance measurement of high
power GaN-based light-emitting diodes (LEDs). The investigated variables include ambient
temperature, thermal interface material (TIMs) at different pressure. The combination of transient
thermal measurement method and optical measurement was employed for the study. The measured
thermal resistance of LED packages was found to increase with the ambient temperature. The
temperature dependence of optical efficiency, forward voltage, and thermal properties of packaging
materials are thought to be responsible for the increase of thermal resistance with the ambient
temperature. The interface effect on the thermal resistance was studied by applying different external
pressure on the interface with different TIMs. And the measured thermal resistances were found to
reach stabilization at certain pressure level after initial decrease with the external applied pressure.
Fabrication and Characterization of SiO2 Based Waveguide Co-Doped with Si-Nanocrystal and Er3+
Authors: Choi Se Weon , Son Hyeon Taek , Kang Chang Seog , Nishii Junji
Published: March 2009

Si and Er co-doped SiO2 films were fabricated by radio-frequency (RF) magnetron
sputtering technique with a Si-Er-SiO2 target. The optical gain of 0.7 dB/cm was confirmed by the
direct pumping of Er3+ using the laser diode (LD) of 980 nm in wavelength and 60 mW in output
power. On the contrary, the pumping Si-nanocrystals by the Hg lamp 365 nm (1.5 W/cm2) induced the
absorption loss above 1.48 μm region in wavelength, which was attributed to the free carrier
absorption of Si-nanocrystals.
Patterning of the Self-Assembled Monolayer Using the Zero Residual Nano-Imprint Lithography
Authors: Yang Ki Yeon , Kim Jong Woo , Hong Sung Hoon , Lee Heon
Published: March 2009

Self-Assembled Monolayer (SAM) is a single layer of ordered molecules absorbed on a
surface by chemical bonding between the molecular head group and the surface. The surface
properties can be controlled by the terminal functional group of the SAM layer. In order to utilize
SAM layers for device applications, SAM layer needs to be patterned as a sub-micron size. Patterning
of SAM layer in sub-micron size has been done by various techniques including direct-writing by
dip-pen nano lithography, selective etching with UV photons, and selective deposition of SAM layer
by &-contact printing. In this study, silane based SAM layer was patterned to the sub-micron size
using zero residual Nano imprint Lithography, which is regarded as next generation lithography
technique due to its simplicity, high throughput and high resolution pattern transferring capability.
Using zero-residual layer imprinting, 300nm~2um sized SAM patterns can successfully fabricated. In
order to check the surface property of patterned SAM layer, a solution containing nano Ag particles
was spin-coated on the SAM patterned substrate and nano Ag particles were selectively deposited on
the substrate.
OTS-Templated Cobalt Deposition Using Co2(CO)8 Precursor
Authors: Lee Jeong Gil , Park Hee Jung , Lee Jae Gab
Published: March 2009

We have investigated selective deposition of Co thin films on the OTS-patterned glass
surface by using μ-CP(Micro-Contact Printing) coupled with MOCVD(Metal Organic Chemical
Vapor Deposition) method with Co2(CO)8 as a Co precursor. Co thin films in the thickness of 5-180
nm has been selectively formed on the glass surface in the presence of the OTS(Octadecyltrichlrosilane)
monolayer at the temperatures 60-90, at the pressure of 0.03-0.6 Torr. The self-assembled
OTS monolayer on the surface passivates the surface hydroxyl(-OH), adsorption sites for Co
precursors, and thus significantly increases the induction period to nucleate Co metals on the OTS
monolayer, compared with on the bare glass. Lowering the temperature and the processing pressure is
likely to increase the difference in the induction period for the two substrate surfaces and thus
improves the selectivity. About 180 nm-thick Co thin film was selectively formed on the
OTS-patterned glass at 70, however, lowering the temperature to 60 decreased the thickness,
which is attributed to the reduced growth rate of Co at the lower temperature. The Co thin films
deposited at 60-90 and at 0.03-0.6 Torr have the resistivities of 10-20 μ4-cm and are free of
contamination. Consequently, the low temperature process for the selective deposition of Co in the
presence of the OTS monolayer can be utilized for a variety of applications including flexible
electronics and semiconductor devices.
Growth Kinetics and Formation of Uniform Self-Assembled InAs/GaAs Quantum Dots at
Authors: Kim Eui Tae , Madhukar Anupam
Published: March 2009

We discuss the growth kinetics of InAs/GaAs self-assembled quantum dots (QDs) using
two different InAs deposition rates, relatively fast growth rate of 0.22 ML/sec and slow growth rate of
0.054 ML/sec. With increasing InAs deposition amount to 3.0 ML, the QD density was almost
constant after 2D to 3D island transition at the slow deposition rate while the QD density kept
increasing and the QD size distribution was relatively broad at the fast growth rate. After the 2D to
3D transition, at the slow growth rate, further deposited In adatoms seemed to incorporate primarily
into already formed islands, and thus contribute to equalize island size. The photoluminescence (PL)
full-width at half maximum (FWHM) of 2.5 ML InAs QDs at 0.054 ML/sec was 23 meV at 78K. The
PL characteristics of InAs/GaAs QDs were degraded significantly after thermal annealing at 550 oC
for 3 hours.
Low Temperature Growth of ZnO Nanorod on Various Substrates by Solution Chemical Method
Authors: Yi Sung Hak , Jang Jae Min , Choi Seung Kyu , Jung Woo Gwang
Published: March 2009

The ZnO seed precursor was prepared by sol-gel reaction. ZnO nanorod arrays were
fabricated by solution chemical deposition on ZnO coated seed substrates. The substrates used are
Si wafer, glass and PET. The fabricated ZnO nanorod had hexagonal morphology, length of
400~500 nm and diameter of 25~50 nm. The ZnO seeds were indispensable for the aligned growth
of ZnO nanorod. The ZnO nanorod growth was dependent on the seeding method used but
independent of the substrates. The structure of ZnO nanorod was characterized by FE-SEM, XRD
and FE-TEM. This method enables large scale growth of ZnO arrays on all kinds of substrates
including polymers.
Industrial Applications of Sol-Gel Technology
Authors: Hong Young Jun , Yi Gi Ra
Published: March 2009

In present paper, various industrial applications of the sol-gel technology will be briefly
introduced. In particular, the current development status and technological issues of sol gel derived
functional nanoparticles in electronic and industrial materials will be reviewed. Productions and
surface modifications of nanoparticles by sol-gel processing, their incorporations into
nanocomposites and final applications are described.