bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF STARCH BINDERS IN ALUMINA COATINGS ON AISI 316 L STAINLESS STEEL FOR MEDICAL APPLICATION
Authors: GHAZALI M. J. , PAUZI A. A. , AZHARI C. H. , GHANI J. A. , SULONG A. B. , MUSTAFA R.
Published: April 2009

A slurry immersion technique of alumina coatings was carried out on several AISI 316 L stainless steels using two types of binding agents; commercial starch and Sarawakian starch (sago), which were also mixed with polyvinylchloride (PVA) for strengthening purposes. The sintering temperatures in this work were varied from 500 to 1000°C. Prior to sintering process, all stainless steels were metallographically ground and polished to approximately 0.6 µm of average roughness. Detailed characterisations on the sintered specimens were carried out with the aid of the secondary electron microscopy (SEM), microhardness and a profilometer. The results revealed that coated steels using sago binder showed improved adhesion and homogenous microstructures with greater hardness of 2642 HV than those found in coated steel with commercial starch after sintering process.
FORMATION MECHANISM OF POROUS STRUCTURE ON 316L STAINLESS STEEL BY ANODIZATION
Authors: WANG YUJIANG , MA XINXIN , TANG GUANGZE
Published: April 2009

The micro-pores with size of 0.2 to 1.8 µm, which randomly distribute in a 316L stainless steel substrate, were fabricated by the transfer of the porous structure of anodic porous alumina. The mask anodic porous alumina was directly prepared by anodizing of aluminum film, which was deposited on 316L substrate by DC magnetron sputtering. The transfer of the porous structure of anodic alumina into the 316L substrate could be achieved without the additional through-hole treatment to the barrier layer. The localized priority dissolution on porous alumina is observed during the anodizing. And this process is considered to lead to the micro-pores formation on 316L substrate. In addition, the effect of anodizing time on the pores size and number on 316L substrate also was discussed.
EPITAXIAL GROWTH OF NON-POLAR A-PLANE ZNO ON R-PLANE SAPPHIRE SUBSTRATES BY MOCVD AND RF-SPUTTERING
Authors: CHEN HOU-GUANG , CHEN GUO-JU , JIAN SHENG-RUI , HUANG GOU-ZHI , NI JHIH-WEI
Published: April 2009

Epitaxial growth of non-polar [Formula: see text] thin films (a-plane ZnO ) on [Formula: see text] sapphire ( r -plane sapphire) were successfully implemented through metal organic chemical vapor deposition (MOCVD) and radio-frequency sputtering, respectively. For ZnO film deposited by sputtering, the growth temperature and the flow ratios of argon to oxygen were shown to significantly influence the crystalline quality and surface morphology of ZnO films. Flat surface ZnO epitaxial film can be grown by MOCVD. The epitaxial relationship between ZnO and sapphire substrate is [Formula: see text] and [Formula: see text]. The full width at half maximum (FWHM) of X-ray rocking curve for [Formula: see text] reflection peak depends on the orientation of X-ray beam toward sample surface. SEM and AFM observations show the surface morphologies of ZnO epilayers exhibit a stripe-like pattern along ZnO [0001] direction. The higher growth rate along ZnO [0001] and in-plane anisotropic lattice mismatch between a -plane ZnO and r -plane sapphire might result in the formation of such stripes.
EFFECT OF BN/Ti RATIO ON THE REACTION SYNTHESIS OF TiB2-TiNx CERAMICS
Authors: ZHAN LEI , SHEN PING , JIANG QI CHUAN
Published: April 2009

The effects of BN / Ti molar ratio on the self-propagating high-temperature synthesis (SHS) reaction behaviors and final products in the Ti - BN system were experimentally investigated. With an increase in the BN / Ti ratio, the combustion temperature and wave velocity first increase and then decrease with the maximum values displaying at BN / Ti =0.67. A substoichiometric TiN 1- x was obtained for BN / Ti <0.67, and a stoichiometric one was produced for BN / Ti =0.67. Moreover, the microstructure photographs of the products reveal that with the increase of the BN / Ti ratio, the grains of the ceramic phases tend to be finer.
MICROSTRUCTURE IN WORN SURFACE OF HADFIELD STEEL CROSSING
Authors: ZHANG F. C. , LV B. , WANG T. S. , ZHENG C. L. , LI M. , ZHANG M.
Published: April 2009

In this paper a failed Hadfield (high manganese austenite) steel crossing used in railway system was studied. The microstructure in the worn surfaces of the crossing was investigated using optical microscopy, scanning electron microscopy, transmission electron microscopy and Mössbauer spectroscopy. The results indicated that a nanocrystallization layer formed on the surface of the crossing served. The formation mechanism of the nanocrystalline is the discontinuous dynamic recrystallization. The energy for the recrystallization nucleus formation originates from the interactions between the twins, the dislocations, as well as twin and dislocation. High-density vacancies promoted the recrystallization process including the dislocation climb and the atom diffusion.
TEM INVESTIGATION ON CRYSTALLIZATION BEHAVIOR OF A Fe68C10.5Si4.4B6.5P8.6Al2 BULK METALLIC GLASS
Authors: KIM KI BUEM , LI HONG XIANG , YI SEONGHOON
Published: April 2009

TEM investigations on crystallization behavior of a Fe 68 C 10.5 Si 4.4 B 6.5 P 8.6 Al 2 bulk metallic glass reveals that the nano-scale fcc Fe phase formed by primary crystallization is homogeneously embedded in the amorphous matrix after heat treatment at 783 K for 30 min. With increasing heat treatment time (783 K for 45 min), a tetragonal Fe 3( C , B , P ) phase encapsulates the primary fcc Fe phase suppressing the growth of the fcc Fe phase. The Fe 3( C , B , P ) phase decomposes into a mixture of orthorhombic Fe 3( C , P ) and tetragonal Fe 3( B , P ) upon further annealing treatment at 783K.
SIMULATING THE EFFECT OF POISSON RATIO ON METALLIC GLASS PROPERTIES
Authors: MORRIS JAMES R. , AGA RACHEL S. , EGAMI TAKESHI , LEVASHOV VALENTIN A.
Published: April 2009

Recent work has shown that many metallic glass properties correlate with the Poisson ratio of the glass. We have developed a new model for simulating the atomistic behavior of liquids and glasses that allows us to change the Poisson ratio, while keeping the crystalline phase cohesive energy, lattice constant, and bulk modulus fixed. A number of liquid and glass properties are shown to be directly affected by the Poisson ratio. An increasing Poisson ratio stabilizes the liquid structure relative to the crystal phase, as indicated by a significantly lower melting temperature and by a lower enthalpy of the liquid phase. The liquids clearly exhibit two changes in behavior: one at low temperatures, associated with the conventional glass transition Tg, and a second, higher temperature change associated with the shear properties of the liquids. This second crossover has a characteristic, measurable change in the liquid structure.
CHARACTERIZATION AND APPLICATION OF CONDUCTING POLYMER COATED TEXTILES
Authors: WANG LIJING , LIN TONG , WANG XUNGAI
Published: April 2009

This paper reports on some physical properties of a conducting polymer, polypyrrole, coated textiles. Polypyrrole was coated on textiles chemically through in-situ solution or vapor polymerisation to produce conducting textiles. The effects of the conductive coating on the physical and mechanical properties of the fibrous materials are presented. The coating durability and conductivity of the textiles have also been examined.
MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TI-BASED METALLIC GLASS MATRIX COMPOSITES
Authors: WANG JIANLI , HU WEN , WANG LIDONG , WU YAOMING , WANG LIMIN
Published: April 2009

Ti 40 Cu 40 Ni 10 Zr 10-x Sc x (x = 0.5 and 1, at%) alloys were prepared by copper mould casting method. Microstructures of the ɸ 3 mm rod alloys were investigated by XRD and SEM. The results showed that the ɸ 3 mm rods were glassy matrix with TiCu crystalline phase. Mechanical properties were studied by compressive test. Ti 40 Cu 40 Ni 10 Zr 9 Sc 1 alloy exhibited good compressive strength over 2200 MPa and superior compressive deformation is about 7.9%.
FABRICATION AND RESIDUAL STRESS CHARACTERIZATION OF SQUEEZE INFILTRATED Al18B4O33/Mg FUNCTIONALLY GRADED MATERIAL
Authors: LEE WOOK JIN , YANG JUN SEONG , PARK YONG HA , PARK BONG GYU , PARK IK MIN , PARK YONG HO
Published: April 2009

In this study, three types of functionally graded Al 18 B 4 O 33/ Mg composites which consisted of 2, 3 and 4 layers and where volume fractions of Al 18 B 4 O 33 were gradually changing from 0 to 35% were fabricated using squeeze infiltration technique. The mechanical parameters of each layer were measured for the analysis of residual stress. Elastic finite element numerical models were applied to the analysis of thermal residual stress. The analytic results showed that the residual stresses were significantly decreased in the macrointerface with increasing the number of layer.
EVALUATION OF PITTING CORROSION OF THE SiCP/5A06 ALUMINUM METAL COMPOSITE IN 3.5% NaCl SOLUTION BY MEANS OF ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS)
Authors: AZIZ IRFAN , ZHANG QI
Published: April 2009

The corrosion behavior of the silicon carbide particulates (17.5 vol.%) reinforced 5A06 aluminum alloy metal matrix composite (MMC) and the 5A06 aluminum matrix alloy has been studied in 3.5% NaCl solution at 35°C by using electrochemical impedance spectroscopy (EIS). Analysis of the results, which were obtained from optical (OM) and scanning electron microscopy (SEM) attached with energy dispersion spectroscopy (EDS), indicate that the corrosion behavior of the materials studied was mainly localized corrosion due to the presence of intermetallics ( Al ( Mn , Fe ), Al ( Si , Mg )) on the surface and crevices at the interface of SiCp/matrix . More numerous, wider spread, smaller and shallower pits were noted on the composite surface relative to the unreinforced matrix alloy during immersion. However, the pitting morphology on both materials was completely different from crystallographic type of pitting. Crystallographic pitting occurred by anodically polarizing the materials above the pitting potential. Further, the occurrence of an inductive time constant at lower frequencies region and the lower impedance as compared to that of the matrix alloy indicate that the corrosion extent of the composite was more severe than that of the matrix alloy, both materials were immersed for varied periods. Two different equivalent circuits were proposed and applied to analyze the EIS measurements, which can simulate the impedance of the composite and the matrix alloy under corrosive environment.
THE PREPARATION AND APPLICATION OF MAGNETIC NANOPARTICLES WITH CORE-SHELL STRUCTURE
Authors: PENG ZHEN , YAO KE-FU , LIAO ZHENHUA , FU WENPENG
Published: April 2009

It is well-known that TiO 2 nanoparticles are highly efficient photocatalysts in decomposing organic substance in wastewater, especially when they are used in suspension state. However, if TiO 2 nanoparticles cannot be withdrawn and reused, it is difficult to apply them in purification of wastewater due to the economic consideration. In present work, TiO 2/ SiO 2/ Fe 3 O 4 core-shell magnetic nanoparticles, constituted by Fe 3 O 4 core, SiO 2 intermediary layer and the TiO 2 out-shell, have been prepared and applied in photocatalytic degradation of a modulated methylene blue containing water. The results indicate that the as-prepared TiO 2/ SiO 2/ Fe 3 O 4 nanoparticles possess high photocatalytic activity and the methylene blue in wastewater can be degraded quickly. Through comparing with the photocatalytic performance of the famous commercial P 25 TiO 2 nanoparticles in the same reaction condition, it has been found that as-prepared TiO 2/ SiO 2/ Fe 3 O 4 nanoparticles exhibit similar photocatalytic activity to commercial P 25 TiO 2 nanoparticles in the photocatalytic degradation of methylene blue containing water. But the TiO 2/ SiO 2/ Fe 3 O 4 nanoparticles used in suspension state can be simply recovered from the liquid by using a magnet or a magnetic field. So the cost of wastewater purification by photocatalytic degradation with TiO 2/ SiO 2/ Fe 3 O 4 nanoparticles can be significantly reduced through reuse of the photocatalyst. It implies that TiO 2/ SiO 2/ Fe 3 O 4 nanoparticles possess the potential for industrial application.
COLOR SCHEMES AND BIOCOMPATIBILITY OF EPOXY RESIN/POLYTETRAFLUORETHYLENE COAT ON THE SURFACE OF TINI ARTH WIRES
Authors: SHAO PING , FENG XUE , SUI JIE HE , CAI WEI , WANG TAO , MA WEI
Published: April 2009

In order to avoid the "metallic smile" appearance of metal wires when undergoing orthodontic treatment, epoxy resin/polytetrafluorethylene coating TiNi arch wires were made by dipping method. TiO 2 and FeFe 2 O 4 were chosen as dyes in order to match the color of teeth and the color schemes were fixed by spectrophotometer method. The biocompatibility of coating was also examined. The results showed that the cytotoxicity of the coating was grade I, and without mutagenesis and carcinogenesis. Skin sensitization assay showed no erythema or oedema response and epithelial was integrated according to mucous membrane irritation. Thus, good behavior in clinic can be anticipated.
NUMERICAL STUDY FOR GTA WELD SHAPE VARIATION BY COUPLING WELDING ARC AND WELD POOL
Authors: DONG WENCHAO , LU SHANPING , LI DIANZHONG , LI YIYI
Published: April 2009

A numerical modeling of the welding arc and weld pool is studied for moving GTA welding to investigate the effect of the surface active element oxygen and the plasma drag force on the weld shape. Based on the 2D axisymmetric numerical modeling of the argon arc, the heat flux, current density and plasma drag force are obtained under different welding currents. Numerical calculations to the weld pool development are carried out for moving GTA welding on SUS304 stainless steel with different oxygen contents 30 ppm and 220 ppm, respectively. The results show that the plasma drag force is another dominating driving force affecting the liquid pool flow pattern, except for the Marangoni force. The different welding currents will change the temperature distribution and plasma drag force on the pool surface, and affect the strength of Marangoni convection and the weld shape. The weld D/W ratio initially increases, followed by a constant value around 0.5 with the increasing welding current under high oxygen content. The weld D/W ratio under the low oxygen content slightly decreases with the increasing welding current. The predicted weld shape by simulation agrees well with experimental results.
NUMERICAL MODELING OF DENDRITIC GROWTH IN ALLOY SOLIDIFICATION WITH FORCED CONVECTION
Authors: SUN DONGKE , ZHU MINGFANG , PAN SHIYAN , RAABE DIERK
Published: April 2009

A two dimensional (2D) cellular automaton (CA) - lattice Boltzmann (LB) model is presented to investigate the effects of forced melt convection on the solutal dendritic growth. In the model, the CA approach of simulating the dendritic growth is incorporated with the kinetic-based lattice Boltzmann method (LBM) for numerically solving the melt flow and solute transport. Two sets of distribution functions are used in the LBM to model the convective-diffusion phenomena during dendritic growth. After validating the model by comparing the numerical results with the theoretical solutions, it is applied to simulate the single and multi dendritic growth of Al - Cu alloys without and with a forced convection. The typical asymmetric growth features of convective dendrite are reproduced and the dendritic morphology is strongly influenced by melt convection. The simulated convective multi dendritic features by the present model are also compared with that by the CA-NS model. The present model is found to be more computationally efficient and numerically stable than the CA-NS model.
MICROSTRUCTURES AND MECHANICAL PROPERTIES OF ULTRAFINE GRAINED Ti-47Al-2Cr (at %) ALLOY PRODUCED USING POWDER COMPACT FORGING
Authors: NADAKUDURU VIJAY N. , ZHANG DELIANG , CAO PENG , GABBITTAS BRIAN
Published: April 2009

Development of innovative techniques to produce gamma TiAl based alloys, with good mechanical properties, while still maintaining ultra fine grain size can be rewarding, but also is a great challenge. In the present study study a Ti -47 Al -2 Cr ( at %) alloy has been synthesized by directly forging green powder compacts of a Ti / Al / Cr composite powder produced by high energy mechanical milling of a mixture of elemental Ti , Al , Cr powders. It has been found that the density of the bulk consolidated alloy sample after forging decreases from 95% of the theoretical density in the central region to 84% in the periphery region. The microstructure of the bulk alloy consisted of several Ti rich regions, which was expected to be mainly due to initial powder condition. The room temperature tensile strength of the samples produced from this process was found to be in the range of 115 – 130 MPa. The roles of canning and green powder compact density in determining the forged sample porosity level and distribution are discussed.
SIZE EFFECT OF FLOW STRESS IN ISOTHERMAL UPSETTING DEFORMATION
Authors: GUO BIN , WANG CHUNJU , SHAN DEBIN , SUN LINING
Published: April 2009

With the miniaturization of parts, size effect occurs. The isothermal forming processes are performed to obtain homogenizing deformation. In the paper, a serial of isothermal upsetting tests are carried out with billets of different dimensions. Difference of flow stress is accepted as the parameter to evaluate the size dependence of flow stress on billets dimensions. The experimental results show that size effect occurs clearly. With the increasing of temperature, the difference of flow stress becomes smaller, which means that the degree of size dependence is reduced. Scatter of flow stress is observed in the tests at room temperature. When the deformation temperature is raised, the fluctuation of flow stress tends towards decreasing. In order to investigate the effect of grain size, different grain size is obtained with the heat treatment process. At the same temperature, the difference of flow stress increases with the increasing of grain size. These phenomena can be explained from the viewpoint of polycrystalline structure of material. The anisotropy of individual grain is appeared obviously, which leads the fluctuation of flow stress. In the isothermal deformation, the effect of single grain is smaller than that at room temperature.
CHARACTERIZATION OF DIFFERENT ORIGIN LIMESTONES BY ESCA AND SEM/EDX IN ORDER TO DETERMINE THEIR SUITABILITY FOR DESULPHURIZATION
Authors: VIITANEN VILLE , LEIRO JARKKO , JÄRVINEN LAURI , EKLUND OLAV
Published: April 2009

CARETECH is a multidisciplinary project supported by the Academy of Finland. The aim of this project is to determine the best natural materials that can be used in desulphurization and carbonation processes using methods from materials science, mineralogy and geology. In this paper, we discuss various properties of limestones, such as the chemical composition, surface structure and define their influence on desulphurization.
MICROSTRUCTURAL EVOLUTION DURING HIGH ENERGY MECHANICAL MILLING AND HEAT TREATMENT OF Cu-(5,10)vol.%Al2O3 NANOCOMPOSITE POWDERS
Authors: MUKHTAR AAMIR , ZHANG DELIANG , GABBITAS BRIAN , KONG CHARLIE , MUNROE PAUL
Published: April 2009

Cu -(5-10) vol .% Al 2 O 3 nanocomposite powders were produced from a mixture of Cu powder and Al 2 O 3 nanopowder using a high energy mechanical milling (HEMM) route consisting of two stages. The microstructural evolution of the Cu – Al 2 O 3 nanocomposite powder particles (or granules) produced after first and the second stages of milling was studied using scanning electron microscopy (SEM), transmission electron microcopy (TEM), scanning transmission electron microscopy (STEM) and energy dispersive X-ray (EDX) mapping. The study confirmed that homogenous dispersion of Al 2 O 3 nanoparticles in the Cu matrix was achieved after the first stage of milling and the relatively large Al 2 O 3 particles were further broken into smaller nanoparticles after the second stage of milling. The milled nanocomposite powders were also heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the microstructural changes of the powder particles as a function of annealing temperature. It was found that after heat treatment at 150°C, the Cu grain sizes decreased due to recrystallisation, and increasing the annealing temperature to 300°C causes slight coarsening of the Cu grains. Further increasing the annealing temperature to 500°C caused significant coarsening of the Cu grains and the Al 2 O 3 nanoparticles. It also appeared that the coarsening of Cu grains in the composite powder particles after annealing at 500°C become less severe with increasing the volume fraction of Al 2 O 3 particles.
PERFORMANCE OF UNCOATED CARBIDE CUTTING TOOL WHEN MACHINING CAST IRON IN DRY CUTTING CONDITION
Authors: JAHARAH A. G. , CHE HASSAN C. H. , GHAZALI M. J. , SULONG A. B. , OMAR M. Z. , NUAWI M. Z. , ISMAIL A. R.
Published: April 2009

This paper presents the performance of uncoated carbide cutting tool when machining cast iron in dry cutting conditions. Experiments were conducted at various cutting speeds, feed rates, and depths of cut according to Taguchi method design of experiment using a standard orthogonal array L 9(34). The effects of cutting speeds (100-146 m/min), feed rates (0.20-0.35 mm/tooth) and depths of cut (1.0-2.0 mm) on the tool life, surface roughness and cutting forces were evaluated using ANOVA. Results showed that the effects of cutting speed, depth of cut and the feed rate were similar affecting the failure of the carbide cutting tools within the range of tested machining parameters. The contribution of cutting speed, feed rate, and depth of cut in controlling the tool life were 32.12%, 38.56% and 29.32% respectively. Whereas, the cutting speed was the main factor influencing the average surface roughness (Ra) value followed by feed rate. These factors contribute 60.53% and 35.59% respectively to the Ra value. On the other hand, cutting forces generated were greatly influenced by the depth of cut (66.52%) and the feed rate (32.6%). Cutting speed was found insignificant in controlling the generated cutting forces.
INVESTIGATION ON MARTENSITIC TRANSFORMATION AND MECHANICAL PROPERTIES OF THE Ni50Mn37-xSn13Fex (x=0, 2, 5, 10) ALLOYS
Authors: FENG YAN , SUI JIEHE , GAO ZHIYONG , CAI WEI
Published: April 2009

The microstructures, martensitic transformation behavior and mechanical properties of Fe -doped Ni - Mn - Sn ferromagnetic shape memory alloys are investigated. The influence of composition on the precipitation of second phase and the improvement of ductility are also explained in this paper. The results show that the phase transformations of Ni - Mn - Sn - Fe alloys are still one-step thermo-elastic transformation. The transformation temperatures increase with the increase of Fe content, and the hysteresis decreases after being doped Fe element, this is mainly due to the difference of atom size and the precipitation of second phase. After homogeneously annealing at 1123K for 12h, the Ni 50 Mn 35 Sn 13 Fe 2 alloy becomes single phase due to the solid solubility of Fe . The breaking strength and maximum compressive strain increase with the increase of doped Fe content due to the solid solution strengthening and second phase strengthening. The fracture of the Ni - Mn - Sn alloy is intergranular crack, and becomes transgranular crack after doping Fe element. The ductility is improved by this means, which is in favour of the application of the Ni - Mn - Sn alloys.
THE INFLUENCE OF SPUTTERING BIAS-VOLTAGE ON LaB6 FILM'S CHARACTERISTICS
Authors: XU JING , MIN GUANGHUI , ZHAO XIAOHUA , HU LIJIE , YU HUASHUN
Published: April 2009

The deposition of lanthanum boride ( LaB 6) thin films by the d.c. magnetron sputtering were studied. XRD, AFM and Stylus Profiler were used to characterize the properties of the deposited films. The XRD was used to study the crystallinity. The results of the XRD showed that the dominant crystal face is (100) face. The crystallinity decreased with the increased bias-voltage value, but the influence of bias-voltage on the films is different on different crystal face. The intensity (100) face was influenced by the bias-voltage more obviously than other faces except the influence of thickness. The diffraction peak maximal intensity of (100) face changed from 1256(on 0V) to 580(on -150V), but the intensity of (110) face changed from 614(on 0V) to 486(on -150V). The rel. int(100%) of (110) face changed from 38.70 to 74.52. The deposition rate decreased with the increased bias-voltage value, but the decreased was not obviously. The maximum and minimum of the deposition ratio were 17.53nm and 13.75nm respectively. Surface morphology of the films was studied by the AFM. The crystallite of the films was less than 50nm. The maximal roughness of the films decreased firstly and increased afterward, and it got the maximum on the -50V bias-voltage.
MICROSTRUCTURE AND OPTICAL PROPERTIES OF ERBIUM DOPED SILICA-BASED FILMS VIA FLAME HYDROLYSIS DEPOSITION AND AEROSOL DOPING
Authors: SUI JIEHE , WANG HAIBO , CAI WEI
Published: April 2009

Silica-based films on Si fabricated by flame hydrolysis deposition were doped with erbium ions using an aerosol doping technique, and co-doped with GeO 2, P 2 O 5 and B 2 O 3. The erbium solution concentration was varied from 4 to 8wt%. The results show that the refractive index of the films is not changed with erbium addition and no OH group is detected for erbium doped silica-based films. An obvious peak was observed at 1.542 µm with the FWHM of 65 nm, which corresponds to the 4 I 13/2 → 4 I 15/2 transition. With the increase of Er solution concentration, the photoluminescence (PL) intensity first increases, then decreases above 6 wt % Er solution concentration. The decrease in PL intensity with concentration is attributed to concentration quenching caused by Er - Er interaction. The dependence of PL intensity on pump power intensity further confirms the concentration quenching is cooperative upconversion.
TRANSFORMATION BEHAVIOR AND SHAPE MEMORY EFFECT OF A CoAl ALLOY
Authors: CHEN FENG , TIAN BING , TONG YUXIANG , ZHENG YUFENG
Published: April 2009

This paper investigates the microstructure, martensitic transformation and shape memory effect of Co -16 Al alloy. The optical micrographs of Co -16 at .% Al alloy quenched from 1200°C show that the ε martensite occurs at room temperature, while some remaining γ phase can also be observed. This microstructure analysis can be supported by XRD pattern. It is shown that the alloy undergoes a martensitic reverse transformation at about 220°C during heating. However, no transformation from the fcc phase to hcp phase is detected by DSC measurement upon cooling. It is thought that the precipitation of β phase by aging at high temperature may suppress the martensitic transformation. The tension strain is 12% and the fracture strength is above 800MPa. No obvious yield deformation is observed from the stress-strain curve. SEM images exhibits many dimples on the fracture surface, which means the fracture mechanism is ductile rupture. Bending test show that only 25% deformation can be recovered due to shape memory effect when the pre-strain is 5%.
MICROSTRUCTURE AND MAGNETIC PROPERTIES OF NANOSTRUCTURED Al2O3-20vol%Fe70Co30 COMPOSITE PREPARED BY HIGH ENERGY MECHANICAL MILLING
Authors: YUSOP MASLEEYATI , ZHANG DELIANG , WILSON MARCUS , STRICKLAND NICK
Published: April 2009

Al 2 O 3-20 vol % Fe 70 Co 30 composite powders have been prepared by high energy ball milling a mixture of Al 2 O 3 powder and Fe 70 Co 30 alloy powder. The Fe 70 Co 30 alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe 70 Co 30 alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al 2 O 3 matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.
SOLVENT EFFECTS ON THE DISPERSION OF LINEAR POLARIZABILITY AND FIRST HYPERPOLARIZABILITY OF PARA-NITROANILINE USING POLARIZABLE CONTINUUM MODEL
Authors: MAKWANI DIKSHA , VIJAYA R.
Published: April 2009

The results of ab-initio calculation of frequency dependent linear polarizability α and first hyperpolarizability β of para-nitroaniline (p-NA) in the presence of different solvents are presented using polarizable continuum model (PCM). Geometry of p-NA in different solvents was optimized using HF/6-31 + G(d,p). Both static and frequency dependent α and β initially increase with an increase in the dielectric constant of the solvent used with p-NA, but subsequently attain an almost constant value. With solvents of higher dielectric constant, the value of static β is more compared to the β value at 1.17 eV but less than the value at 2 eV. Even though the existence of the solvent effect is confirmed from the results, the β values calculated at both 1.17 eV and 2 eV do not show any linear relationship with the dielectric constant and the reaction field factor of the solvents. The first excitation energies of both α and β of p-NA are considerably different in the presence of solvents as compared to their values in the gas phase, but the change with dielectric constant of the solvent is not very significant. The effect of hydrogen bonding between the solute and the solvent molecule on the first excitation energy of hyperpolarizability has been included using the explicit solvent method. The values of the first excitation energy calculated using the explicit method are lower than those obtained by the implicit method.
WALK-OFF LENGTH LIMITED SPECTRAL BROADENING IN SUPERCONTINUUM GENERATION
Authors: SONG H. , PAEK U.-C. , KIM D. Y.
Published: April 2009

Detailed spectrum broadening mechanisms in supercontinuum (SC) generation are studied with an all-fiber pulsed laser source and a highly nonlinear dispersion-shifted fiber (HN-DSF). Mode-locked fiber laser pulses are stretched to four different pulse widths, and SC spectra are measured with different propagation distances with these pulses. By observing the development of spectral width with distance, we have observed that self-phase modulation (SPM) rather than soliton fission is the dominant process at the beginning of SC generation in our case. We have also confirmed that four-wave mixing (FWM) and its walk-off problem associated with different spectral components are the major limiting factors in efficient wide-band SC generation.
BRILLOUIN INSTABILITIES IN CONTINUOUSLY PUMPED HIGH POWER FIBER LASERS
Authors: MALLEK DJOUHER , KELLOU ABDELAMID , LEBLOND HERVÉ , SANCHEZ FRANÇOIS
Published: April 2009

The effect of Brillouin backscattering on the stability of a high power continuously pumped fiber laser is theoretically analyzed in the general framework of two-coupled modes laser model. It is demonstrated that, depending on the cavity losses, different type of instabilities can arise. Low loss cavity favours stable continuous regime in a large range of pumping rates while high loss configuration permits the emergence of different self-pulsing instabilities.
THIRD-ORDER NONLINEAR OPTICAL PROPERTY OF POLY(HEXA-2,4-DIYNYLENE-1,6-DIOXYDICINNAMATE) CONTAINING A POLAR AZO DYE, DETERMINED BY Z-SCAN TECHNIQUE
Authors: ORTEGA ALEJANDRA , PEREZ-MARTINEZ ANA LAURA , OGAWA TAKESHI , SMITH FRANCIS , WALSER ARDIE , DORSINVILLE ROGER
Published: April 2009

A highly-conjugated polar dye with three aromatic rings connected with azo groups was prepared and it was incorporated in polycinnamate. It showed a third-order nonlinear susceptibility of 8 × 10-10 esu determined by a Z-scan technique. The unpoled and poled films show the same susceptibility indicating the polymer film could not be poled. The open aperture Z-scan showed negligible two-photon absorption at 1064 nm.
INVESTIGATION ON THE PUMP ACCEPTANCE BANDWIDTH FOR COLLINEAR QUASI-PHASE-MATCHING OPTICAL PARAMETRIC AMPLIFICATION
Authors: XU HAIBIN , WU BO , CAI SHUANGSHUANG , SHEN YONGHANG
Published: April 2009

We investigated the issue of parametric bandwidth for a collinear quasi-phase-matching (QPM) optical parametric amplification (OPA). Mathematical model for evaluating the parametric bandwidth tolerance of the OPA was derived by expanding the wave-vector mismatch in Taylor series and taking the first two terms into consideration for accuracy. Based on the model, the variation of pump acceptance spectral bandwidth with parametric wavelength was discussed. The correlating curve of the pump wavelength and the parametric wavelength was obtained for the largest pump acceptance spectral bandwidth. These results were compared to that obtained by numerically calculating the parametric gain curves of OPA when pumped with different Gauss bandwidths by means of three-wave mixing equations directly, and were found to be in good accordance. The results presented are helpful for specifying the optimal pump wavelength of the parametric amplification and oscillation.
OPTICAL AXIS GRATINGS IN LIQUID CRYSTALS AND THEIR USE FOR POLARIZATION INSENSITIVE OPTICAL SWITCHING
Authors: NERSISYAN S. R. , TABIRYAN N. V. , STEEVES D. M. , KIMBALL B. R.
Published: April 2009

The ability of optical axis gratings (OAGs) to fully transfer the energy of an unpolarized incident light beam into the ±1st diffraction orders is explored below for development of a polarization-independent optical system with nonlinear transmission. Diffractive properties of OAGs based on azo dye doped liquid crystals (azo LCs) are efficiently controlled with low power radiation. Switching from diffractive to transmissive states of the OAG takes place within 50 ms at 60 W/cm2power density level, while the diffractive state is restored within ~ 1 s in the absence of radiation. High contrast optical switching is demonstrated with violet as well as green laser beams. A photoswitchable OAG is paired with a light-insensitive OAG in diffraction compensation configuration to obtain an optical system switchable from high to low transmission state. The thinness of OAGs required for high contrast switching ensures high overall transmission of the system. Given also the spectrally and angularly broadband nature of OAG diffraction and the capability of azo LC material systems to respond both to cw as well as short laser pulses makes the optical system under discussion very promising for optical switching applications. Presentation of these results is preceded by an "opinionated" review of prior developments and demystifying of the fabrication technique of high efficiency large area OAGs.
Balanced Performance Index and Its Implications: Evidence from Taiwan's Commercial Banks
Authors: Hwang Dar-Yeh , Lee Alice C. , Liu Chi-Chun , Ouyang Lishu
Published: April 2009

Taking into account only financial factors does not provide complete information on performance. This paper takes into consideration of both financial and non-financial performances when evaluating 35 sampled publicly traded commercial banks in Taiwan. The performance of banks is measured using an indexing method consisting of financial and non-financial measures. Banks are classified into two categories according either to the year founded, or to the type of major stockholders of a bank when founded.

The results show that privatized government-owned/old banks are larger than private/new banks, respectively. Moreover, privatized government-owned banks have significantly higher financial performance index than private banks but both types of banks are not significantly different from each other in non-financial performance index. New and old banks are not significantly different from each other in both financial and non-financial performance indexes.

With relatively large scale, higher profitability and better management, banks will perform relatively better among competitors in the following year. Furthermore, non-financial factors are important predictors of future financial and total performance indexes, though individual factor may not be consistently significant.

More branch offices, better capital structure and solvency, and higher rates of growth in deposits and loans all result in more profits, and lead to higher customer satisfaction and more efficient management. Providing better technology to customers is an efficient way in promoting customer services, which in turn produces more profits and results in efficient management. CEOs, on average, have plans for better management and more profits.

Among the factors that have direct and positive impacts on profitability, increasing the efficiency of management is the most efficient way. On the contrary, adding more branch offices contributes the least profits. Therefore, to increase bank profits, CEOs should aim to improve bank management, capital structure and solvency, rather than to add more branch offices.
JULIA SET OF THE NEWTON METHOD FOR SOLVING SOME COMPLEX EXPONENTIAL EQUATION
Authors: WANG XINGYUAN , SONG WENJING , ZOU LIXIAN
Published: April 2009

We extend Kim's complex exponential function and come up with a theory about Julia sets of Newton method for general exponential equation. We analyze the behavior of the roots of some complex exponential equation, and prove the Julia Set's symmetry, boundedness and embedding topology distribution structure of attraction regions in theory.
GENERATION OF OPTIMAL MULTIRESOLUTION MODELS FOR DEFORMING MESH SEQUENCE
Authors: ZHANG SHIXUE , WU ENHUA
Published: April 2009

In this paper, we propose an efficient method to generate optimal multiresolution models for deforming mesh sequence. By this method we define the importance degree of a triangle to be embedded into the quadric error metric (QEM) as a weight parameter, so that the new metric cannot only measure distance error but also reflect geometric variation of local areas. We append a deformation degree weight to the aggregated edge contraction cost for the whole animation. This new metric can preserve not only the model's individual geometric features, but also the features only appeared during the deforming animation. In addition, a mesh optimization method has also been proposed to allow visual distortion of the simplified models to be further alleviated. Our approach is efficient in operation, easy for implementation, and as a result a good quality of dynamic approximations with well-preserved fine details can be generated at any given frame on average.
IMAGE BASED 3D FACE RECONSTRUCTION: A SURVEY
Authors: STYLIANOU GEORGIOS , LANITIS ANDREAS
Published: April 2009

The use of 3D data in face image processing applications has received considerable attention during the last few years. A major issue for the implementation of 3D face processing systems is the accurate and real time acquisition of 3D faces using low cost equipment. In this paper we provide a survey of 3D reconstruction methods used for generating the 3D appearance of a face using either a single or multiple 2D images captured with ordinary equipment such as digital cameras and camcorders. In this context we discuss various issues pertaining to the general problem of 3D face reconstruction such as the existence of suitable 3D face databases, correspondence of 3D faces, feature detection, deformable 3D models and typical assumptions used during the reconstruction process. Different approaches to the problem of 3D reconstruction are presented and for each category the most important advantages and disadvantages are outlined. In particular we describe example-based methods, stereo methods, video-based methods and silhouette-based methods. The issue of performance evaluation of 3D face reconstruction algorithms, the state of the art and future trends are also discussed.
Geochemistry and Tectonics of the Xionger Group in the Eastern Qinling Mountains of China—a mid Proterozoic Volcanic arc Related to Plate Subduction
Authors: Chengzao Jia
Published: April 2009

A mid Proterozoic volcanic series, the Xionger Group, in the eastern Qinling Mountains of central China, may be one of the earliest products of plate subduction in eastern Asia. The main rock types of the 1710 Ma Xionger Group are andesites and dacites of the calcalkaline series. The rocks of the Xionger Group have trace element contents and REE patterns which are comparable to those of lavas from modern active continental margins, implying that the Xionger Group volcanics had a similar tectonic setting. It appears that there was an important event in China at 1800–2000 Ma, after which plate tectonics with the Wilson cycle was the main contributor to crustal growth.
MAGI-1 interacts with Slo1 channel proteins and suppresses Slo1 expression on the cell surface
Authors: Ridgway Lon D. , Kim Eun Young , Dryer Stuart E.
Published: April 2009

Large conductance Ca2+-activated K+ (BKCa) channels encoded by the Slo1 gene (also known as KCNMA1) are physiologically important in a wide range of cell types and form complexes with a number of other proteins that affect their function. We performed a yeast two-hybrid screen to identify proteins that interact with BKCa channels using a bait construct derived from domains in the extreme COOH-terminus of Slo1. A protein known as membrane-associated guanylate kinase with inverted orientation protein-1 (MAGI-1) was identified in this screen. MAGI-1 is a scaffolding protein that allows formation of complexes between certain transmembrane proteins, actin-binding proteins, and other regulatory proteins. MAGI-1 is expressed in a number of tissues, including podocytes and the brain. The interaction between MAGI-1 and BKCa channels was confirmed by coimmunoprecipitation and glutathione S-transferase pull-down assays in differentiated cells of a podocyte cell line and in human embryonic kidneys (HEK)293T cells transiently coexpressing MAGI-1a and three different COOH-terminal Slo1 variants. Coexpression of MAGI-1 with Slo1 channels in HEK-293T cells results in a significant reduction in the surface expression of Slo1, as assessed by cell-surface biotinylation assays, confocal microscopy, and whole cell recordings. Partial knockdown of endogenous MAGI-1 expression by small interfering RNA (siRNA) in differentiated podocytes increased the surface expression of endogenous Slo1 as assessed by electrophysiology and cell-surface biotinylation assays, whereas overexpression of MAGI-1a reduced steady-state voltage-evoked outward current through podocyte BKCa channels. These data suggest that MAGI-1 plays a role in regulation of surface expression of BKCa channels in the kidney and possibly in other tissues.
Role of the glutamate 185 residue in proton translocation mediated by the proton-coupled folate transporter SLC46A1
Authors: Unal Ersin Selcuk , Zhao Rongbao , Goldman I. David
Published: April 2009

The proton-coupled folate transporter (PCFT) SLC46A1 mediates uphill folate transport into enterocytes in proximal small intestine coupled to the inwardly directed proton gradient. Hereditary folate malabsorption is due to loss-of-function mutations in the PCFT gene. This study addresses the functional role of conserved charged amino acid residues within PCFT transmembrane domains with a detailed analysis of the PCFT E185 residue. D156A-, E185A-, E232A-, R148A-, and R376A-PCFT mutants lost function at pH 5.5, as assessed by transient transfection in folate transport-deficient HeLa cells. At pH 7.4, function was preserved only for E185A-PCFT. Loss of function for E185A-PCFT at pH 5.5 was due to an eightfold decrease in the [3H]methotrexate (MTX) influx Vmax; the MTX influx Kt was identical to that of wild-type (WT)-PCFT (1.5 μM). Consistent with the intrinsic functionality of E185A-PCFT, [3H]MTX influx at pH 5.5 or 7.4 was trans-stimulated in cells preloaded with nonlabeled MTX or 5-formyltetrahydrofolate. Replacement of E185 with Leu, Cys, His, or Gln resulted in a phenotype similar to E185A-PCFT. However, there was greater preservation of activity (∼38% of WT) for the similarly charged E185D-PCFT at pH 5.5. All E185 substitution mutants were biotin accessible at the plasma membrane at a level comparable to WT-PCFT. These observations suggest that the E185 residue plays an important role in the coupled flows of protons and folate mediated by PCFT. Coupling appears to have a profound effect on the maximum rate of transport, consistent with augmentation of a rate-limiting step in the PCFT transport cycle.
Short-term blackcurrant extract consumption modulates exercise-induced oxidative stress and lipopolysaccharide-stimulated inflammatory responses
Authors: Lyall K. A. , Hurst S. M. , Cooney J. , Jensen D. , Lo K. , Hurst R. D. , Stevenson L. M.
Published: April 2009

Exercise-induced oxidative stress is instrumental in achieving the health benefits from regular exercise. Therefore, inappropriate use of fruit-derived products (commonly applied as prophalytic antioxidants) may counteract the positive effects of exercise. Using human exercise and cellular models we found that 1) blackcurrant supplementation suppressed exercise-induced oxidative stress, e.g., plasma carbonyls (0.9 ± 0.1 vs. 0.6 ± 0.1 nmol/mg protein, placebo vs. blackcurrant), and 2) preincubation of THP-1 cells with an anthocyanin-rich blackcurrant extract inhibited LPS-stimulated cytokine secretion [TNF-α (16,453 ± 322 vs. 10,941 ± 82 pg/ml, control vs. extract, P < 0.05) and IL-6 (476 ± 14 vs. 326 ± 32 pg/ml, control vs. extract, P < 0.05)] and NF-κB activation. In addition to its antioxidant and anti-inflammatory properties, we found that postexercise plasma collected after blackcurrant supplementation enhanced the differential temporal LPS-stimulated inflammatory response in THP-1 cells, resulting in an early suppression of TNF-α (1,741 ± 32 vs. 1,312 ± 42 pg/ml, placebo vs. blackcurrant, P < 0.05) and IL-6 (44 ± 5 vs. 36 ± 3 pg/ml, placebo vs. blackcurrant, P < 0.05) secretion after 24 h. Furthermore, by using an oxidative stress cell model, we found that preincubation of THP-1 cells with hydrogen peroxide (H2O2) prior to extract exposure caused a greater suppression of LPS-stimulated cytokine secretion after 24 h, which was not evident when cells were simultaneously incubated with H2O2 and the extract. In summary, our findings support the concept that consumption of blackcurrant anthocyanins alleviate oxidative stress, and may, if given at the appropriate amount and time, complement the ability of exercise to enhance immune responsiveness to potential pathogens.