bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characterization of Calcium Titanate (CaTiO3) Whiskers via Molten Salt Method
Authors: Zhang Yong Xing , Nai Xue Ying , Wei Ming , Zhu Dong Hai , Zhu Cheng Cai , Li Wu
Published: December 2012

Well dispersive and single crystal calcium titanate (CaTiO3) whisker with a length of 50-100μm was synthesized by sintering the mixture of calcium chloride and titanium dioxide with improvement of adding the mineralization agent of Pb(Ac)2.3H2O. The as-prepared samples were characterized by XRD, SEM. The optimum synthesis condition and the effect of the mineralization agent were discussed respectively. In the end, the possible reaction process was given and a LS growth mechanism was proposed.
The Study of Electrical Transport in Rubber Blends Filled by Single Wall Carbon Nanotubes
Authors: Jančíková Zora , Koštial Pavel , Bakošová D. , Ružiak Ivan , Frydrýšek K. , Valíček Jan , Farkašová M. , Puchký R.
Published: December 2012

The paper deals with the electrical and mechanical properties of rubber blends filled by single wall carbon nanotubes (SWCNT-0,6 weight %). We have investigated the alternating current resistivity (ACR), real and imaginary part of dielectric constant,and loss factor .The addition of (SWCNT) to a rubber blend decreases ACR and increases constants ,and loss factor .
The Effect of Nanoparticles Crystallite Size on the Recovery Efficiency in Dielectric Nanofluid Flooding
Authors: Zaid Hasnah Mohd , Yahya Noorhana , Latiff Noor Rasyada Ahmad
Published: December 2012

Application of nanotechnology in enhanced oil recovery (EOR) has been increasing in recent years. After secondary flooding, more than 60% of the original oil in place (OOIP) remains in the reservoir due to trapping of oil in the reservoir rock pores. One of the promising EOR methods is surfactant flooding, where substantial reduction in interfacial tension between oil and water could sufficiently displace oil from the reservoir. In this research, instability at the interfaces is created by dispersing 0.05 wt% ZnO nanoparticles in aqueous sodium dodecyl sulfate (SDS) solution during the core flooding experiment. The difference in the amount of particles adsorbed at the interface creates variation in the localized interfacial tension, thus induces fluid motion to reduce the stress. Four samples of different average crystallite size were used to study the effect of particle size on the spontaneous emulsification process which would in turn determine the recovery efficiency. From the study, ZnO nanofluid which consists of larger particles size gives 145% increase in the oil recovery as compared with the smaller ZnO nanoparticles. In contrast, 63% more oil was recovered by injecting Al2O3nanofluid of smaller particles size as compared to the larger one. Formation of a cloudy solution was observed during the test which indicates the occurrence of an emulsification process. It can be concluded that ultralow Interfacial tension (IFT) value is not necessary to create spontaneous emulsification in dielectric nanofluid flooding.
Determination Reflection and Transmission Coefficients of Lanthanum Iron Garnet Filled PVDF-Polymer Nanocomposite Using Finite Element Method Modeling at Microwave Frequencies
Authors: Soleimani Hasan , Yahya Noorhana , Abbas Zulkifly , Soleimani Hojjatollah , Zaid Hasnah Mohd
Published: December 2012

In our previous work, the lanthanum iron garnet-filled PVDF-polymer nanocomposite has been prepared. The reflection and transmission coefficients of PVDF/LIG were measured using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) at X-band frequencies (8 GHz - 12 GHz). In this study, the distribution of electric field intensity of PVDF/ LIG which was loaded in rectangular waveguide was simulated based on Finite Element Method (FEM) formulation to show the essential differences of intensity of emitted electrical field. The computations of reflection and transmission coefficients of PVDF/ LIG were determined by using implementation FEM modeling rectangular waveguide. The FEM results were compared with the experimental achievement results using the rectangular waveguide. An excellent agreement between measured and simulated results was obtained based on the values of mean relative errors.
Numerical Modeling of the Eigenmodes and Eigenfrequencies of Carbon Nanotubes under the Influence of Defects
Authors: Ghavamian Ali , Öchsner Andreas
Published: December 2012

Two configurations of perfect single walled carbon nanotubes (armchair and zigzag) were simulated based on the finite element method. Then, three most likely defects (Si-doping, carbon vacancy and perturbation) were introduced to the models to represent defective forms of single walled carbon nanotubes (SWCNTs). Finally, the vibrational properties of perfect and defective carbon nanotubes were evaluated and compared. The results showed that SWCNTs have a natural frequency with a rather high value between 18.69 and 24.01 GHz. In the consideration of the natural frequency of the defective SWCNTs, it was also observed that the existence of any type of defects or irregularities leads to a lower value of natural frequency and vibrational stability. Simple mathematical relations which express the change in natural frequency versus the percentage of the defect were also presented. This can be very useful to realistically estimate the influence of defects of different amounts on the vibrational behavior of carbon nanotubes.
Thermal Behavior of Clay/Epoxy Nanocomposites
Authors: Leal Artur S.C. , de Araújo Carlos José , Silva Suédina Maria L. , de Lima Antônio Gilson Barbosa
Published: December 2012

In this work, the effect of curing agent, curing conditions and the incorporation of small amounts of organoclay on the thermal properties of DGEBA (diglycidyl ether of bisphenol A) epoxy resin was evaluated in order to develop an epoxy system for application as the matrix in active composites whose dispersed phase consists of shape memory alloy wires. The DGEBA resin was prepared using three amine derivatives as hardeners (triethylenetetramine - TETA, diethylenetriamine - DETA and diaminodiphenylsulfone - DDS) under varied curing conditions, in the absence and presence of organoclay. Epoxy systems were characterized by dynamic mechanical analysis (DMA), optical microscopy and X-ray diffraction. According to the obtained results, the cured DETA and DDS epoxy systems at elevated temperatures, above 180°C, showed a higher glass transition temperature (Tg) and thermal stability values than the system cured at low temperature (TETA). In addition, when the post-cure treatment was used, an improvement of the thermal stability was verified. When 1 phr (parts hundred resin) of organoclay was incorporated in DETA and DDS cured epoxy systems and post-cured, either the increase in the Tg and thermal stability values were more significant, especially for the system cured with DDS. Hence, the epoxy/DDS/organoclay system (exfoliated nanocomposite) is the most appropriate to be used as the matrix in the preparation of active composites since this matrix is thermally stable in the Ni-Ti shape memory alloy working range whose phase transformation occurs between 70 and 80 °C.
Hydrothermal Growth of ZnO Hexagonal Nanocrystals: Effect of Growth Conditions
Authors: Promnimit Sujira , Baruah S. , Lamdu U. , Dutta Joydeep
Published: December 2012

Hexagonal ZnO nanocrystals were synthesized through a hydrothermal route under mild conditions (growth temperature of 90°C at atmospheric pressure). Pre-synthesized ZnO nanoparticles were used to serve as nucleation sites for the growth of the nanocrystals. The growth of ZnO nanorods was found to be surface independent. The dimensions of the hexagonal ZnO nanocrystals were observed to be dependent on the concentration of the reactants used (sources of Zn2+ and OH-ions), pH of the growth bath and also on the duration of crystal growth. The average diameter and height of the ZnO nanocrystals was found to be directly proportional to the concentration of the reactants as well as hydrolysis time. The orientation of the nanocrystals was found to be dependent upon the seeding method employed. Hexagonal single crystals of a wide range of dimensions and aspect ratios could be successfully synthesized through a control of growth parameters.
Characterization of Titania Nanoparticles Synthesized by the Hydrothermal Method with Low Grade Mineral Precursors
Authors: Mahdi E.M. , Abdul Shukor Mohd Hamdi , Meor Yusoff M.S. , Wilfred Paulus
Published: December 2012

The objective of this work is to utilize a low-grade synthetic rutile to produce high-grade titania nanoparticles. Due to the nature of the precursor, the hydrothermal method needs modification in order to accommodate the precursors and chemical reagents. The product will be characterized with the XRD (crystallite size and crystallinity), EDXRF (chemical composition), SEM (Morphology), N2 adsorption-desorption (Surface Area) and UV-Vis-NIR. Results revealed a crystallite size of less than 20 nm, a surface area of 186.8 m2/g, a morphology that is a combination of agglomeration and particles, and an optical band gap of 3.23 eV. It is concluded that synthetic rutile is a viable precursor to produce high quality titania nanoparticles.
Development of a Mathematical Model for Natural Gas Permeation through Polymer Nanocomposites at High Pressure and Temperature
Authors: Adewole Jimoh K. , Hussein Ibnelwaleed A. , Al-Mubaiyedh Usamah A.
Published: December 2012

A mathematical model for predicting the permeability of natural gas in polymer nanocomposites was developed and tested using experimental data. The model takes into account the effects of pressure, temperature, crystallinity and nanoparticle loading. Three model parameters (, and) were obtained. The parameter is a measure of the activation energy, described the effect of nanocomposite loading, and can be used to describe the effect of gas concentration on the. Polymer nanocomposites were prepared using high density polyethylene as polymer matrix and Cloisite 15A as nanoclay. The proposed model was used to predict the permeability of the nanocomposites to pure CH4 and mixed CH4/CO2 gases (containing 80 mol% CH4) at pressures up to about 106 bar and temperatures between 30 to 70°C. Predicted results show that the developed model provides an excellent description of natural gas permeation in pure HDPE and its nanocomposites.
The Interaction of Temperature and Bending Load on Structural Performance of Chinese Larch Wood
Authors: Zhou Hai Bin , Hu Chuan Shuang , Zhou Jian Hui
Published: December 2012

Wood is being used extensively in timber construction in China. In fire-resistant design for timber construction, the main goal is to ensure that enough structural integrity is maintained during a fire to prevent structure collapse. It is important to understand its structural performance when exposed to elevated temperatures and loaded by stress levels. To study the interaction effect of Chinese larch wood, a total of 72 small clear wood samples were observed under constant stress levels when the wood temperature was elevated. The results indicated that Chinese larch wood was more susceptible to the coupling effect of temperature and stress. The interaction promoted a temporary stable flexural structure to collapse during a short exposure time.
Ac Susceptibility of Pr0.5Ca0.5Mn0.99Al0.01O3 at Low Temperatures
Authors: Wang Ji Liang , Qian Cheng , Yu Li , Qi Da Wei
Published: December 2012

Pr0.5Ca0.5Mn0.99Al0.01O3 compound was prepared by standard solid state reaction to study its ac susceptibility at low temperatures. The X-ray powder diffraction patterns show that the compound is single-phase orthorhombic structure. The cusps of charge ordering and the long range AFM order of the “pseudo”-CE type are suppressed with Al dopping in Pr0.5Ca0.5MnO3 compound. ZFC and FC magnetization of this compound bifurcate at Tf. The behavior of ac susceptibility at low temperatures is investigated. The intensity of the real component ' at the freezing temperature Tf is suppressed with the increase of frequency. Tf is linear with the logarithm of the frequency. The normalized slope P = ΔTf/TfΔlog10ω, which is much lower than canonical insulating spin glass systems in which 0.06 ≤ P ≤ 0.08. The intensity of '' at Tf increases with the increase of frequency. The ground state of this sample is cluster glass.
Influence of Heat Treatment and Deformation on the Phase-Structural State of Steel 30CrMnSiA
Authors: Skakov Mazhyn , Uazyrkhanova Gulzhaz , Popova Natalya , Sheffler Michael
Published: December 2012

Investigated the fragmented substructure of steel 30CrMnSiA after heat treatment and deformation. Found that after heat treatment of steel is the main component of α-phase (~ 96%), γ- phase (~ 3%) is present in the material in the form of residual austenite. Batch martensite is 0.7 on the volume of α- phase plate - 0.3. Most of the residual martensite (1.5%) is located in the plate martensite, the lowest - in a fragmented packet martensite component (~ 0.5%). In unfragmented batch martensite of residual austenite is present in an amount of 1%. Found that in the process of deformation martensite structure formed after heat treatment is completely destroyed and the volume fraction of anisotropic fragments is 25%, 75%-isotropic. Electron microscopic studies have shown that originated fragmented structure is stabilized by tertiary carbides formed during deformation. These carbides are cementite particles and special carbide M6C. These particles are located mainly along the boundaries and junctions of the fragments.
Online-Joining of C/SiC-C/SiC via Slurry Reaction and Precursor Infiltration and Pyrolysis Process with C/SiC Pins
Authors: Zhang Yu Di , Hu Hai Feng , Zhang Chang Rui , Li Guang De
Published: December 2012

C/SiC composites have widely application prospects in the field of aeronautic and aerospace for their excellent properties. The joining of C/SiC composites is a key to fabricate large and complex components. In this paper, 1D C/SiC pins were prepared by precursor infiltration and pyrolysis (PIP) process and used to join C/SiC composites by Slurry react (SR) and PIP process. The shear strength of the C/SiC pins with different carbon fiber volumes was investigated with the maximum shear strength as high as 339.46MPa. Influences of C/SiC pins on the joining properties of C/SiC composites were studied. The shear strength and flexural strength of C/SiC-C/SiC joining are improved from 9.17MPa and 30.41MPa without pins to 20.06MPa and 75.03MPa with one C/SiC pin (diameter 2mm), respectively. The reliability of C/SiC-C/SiC joining is also improved with C/SiC pins in that the fracture mode changes from catastrophic without pins to non-catastrophic. The SEM photos show a strong bond between joining layer and C/SiC composites without obvious interface.
A New Deep Red-Emitting Mn2+-Activated SrLaGa3S6O Phosphor
Authors: Yu Rui Jin , Park Jin Young , Yang Hyun Kyoung , Moon Byung Kee , Choi Byung Chun , Jeong Jung Hyun
Published: December 2012

A new deep red-emitting Mn2+-activated SrLaGa3S6O phosphor was first prepared by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation and emission spectra. The emission spectrum shows a broad band with an emission maximum at 668 nm under the host excitation of 340 nm. The full width at half maximum (FWHM) of the emission peak is about 83 nm. The CIE chromaticity coordinates (x = 0.673 and y = 0.312) shows that the phosphor emission is in the deep red region and were very near to the NTSC standard values for red. Since the excitation band of the phosphor lies in the near UV excitable region, giving a deep red emission, it can be used for applications in near UV phosphor converted white LED lighting and display devices.
An Empirical Relationship to Predict Damages in Carbon Fiber Reinforced Composites under Extreme Thermal Cycling Conditions
Authors: Siddiqui Fateeha Nisar , Saleh Nada , Rahat Ayesha , Israr Asif , Rehman Atiq Ur
Published: December 2012

Carbon Fiber Reinforced Composites are presently used in satellites structure for better performance during extreme thermal cycling space environment. These materials display unexpected failure because the satellite periodically goes into and out of the earth shadow region on orbit, leading to a change in its surface temperature. As the coefficient of thermal expansion of carbon fibers is an order of magnitude lower than that of the polymer matrix, repeated thermal stresses are generated in the composites under the alternative temperature field, resulting in damage to the materials and a decrease in mechanical properties. The main objective of this study is to develop an analytical model to predict the damage produce in the composites subjected to extreme thermal loading. These thermal loading also causes the material to release strain energy. The results are presented in terms of strain produced during thermal cycling and also in the process of delamination.
Growth of GaAsP by Solid Source Molecular Beam Epitaxy
Authors: Jiao Gang Cheng , Liu Zheng Tang , Shi Feng , Zhang Lian Dong , Cheng Wei , Wang Shu Fei , Zhou Yu Jian , Miao Zhuang
Published: December 2012

The GaAsP crystal material grown on GaAs substrate has been extensive applications in the area of photoelectronic device. There because GaAsP have advantageous photoelectronic performance and adjustable band gap. We report growth of GaAs1-xPx grown on GaAs substrate by solid source molecular beam epitaxy (SSMBE). On the basis of the optimized Ⅴ/Ⅲ flux ratio, appropriate growth rate, and the substrate temperature for sample growth, different composition GaAs1-xPx layers had been grown on GaAs top. Lattice-mismatched became the big challenges to high-quality epitaxial growth of the GaAs1-x Px materials on GaAs substrate. The crystalline quality, surface morphology were performed by applying high resolution X-ray diffractometry (HRXRD) and high resolution optical microscopy. The etched region and internal defect were also investigated.
Temperature Field Analysis on CA Mortar Ballastless Track of High-Speed Railway
Authors: Fu Jun , Qin Yu , Yu You Yun , Ye Meng Jun , Li Lian Xin
Published: December 2012

As an important cushion layer, CA mortar ballastless track is crucial to the durability, safety of high-speed railway and the high-speed railway is influenced by the external environment. The regulation of temperature field evolvement of ballastless track is analyzed in this paper through a two-dimensional, transient finite element model built by ANSYS. The results show that the temperature of structure section caused by solar radiation and circumstances temperature is decreasing along depth in sunlight, and the internal temperature of structure is higher than the surface temperature at night. The integral temperature field of structure reaches the maximum at 1:00 p.m. and the vertical difference of the temperature inside the structure is also the largest, causing the most obvious temperature stress, which provides theoretical data for systematic research on ballastless track of high-speed railway.
The Influence of Ni and Cr on the Primary Austenite Dendrite in D-type Graphite Cast Iron
Authors: Chu Di , Yue Xu Dong , Xu Shu , Liu Jin
Published: December 2012

The influence of Nickel and Chromium alloy element on the primary austenite dendrite in D-type graphite was studied in this paper. The results show, as the addition amount of Nickel is equal to 0.64 percent, the development of the primary austenite dendrite is short and strong. As the addition amount of Chromium is equal to 0.64%, the primary austenite dendrite is no direction. The influence of us joins the Chromium alloy element on the change of organization. The adding amount of Nickel and Chromium is 0.6, 0.8 and 1.0 percent. The hardness of D type graphite increase with the amount added.
Influence of Regimes Electrolytic Plasma Cementation on the Mechanical Properties of Steel 12Cr18Ni10Ti
Authors: Skakov Mazhyn , Kurbanbekov Sherzod , Scheffler Michail
Published: December 2012

In the present work the results of electrolytic-plasma treatment influence on the mechanical properties and structural-phase condition of steel’s 12Cr18Ni10Ti surface layers. In the work, the mechanical characteristics of steel’s surface layers are investigated, cemented in electrolytic plasma with the composition 10 % Nа2CO3 and 10 % С3Н8О3. The operational parameters for the processing are determined. The optimal content of components in saturating mixtures plasma by cementation defined. According to the study it is found that, after electrolyte plasma processing, high hardness increased in 2-2.5 times more than in the original condition. The hardened layer with thickness 30-65 µm is formed. It is shown that after the electrolyte-plasma processing of steel 12Cr18Ni10Ti, microstructure contains particles carbides and has fine-grained martensitic structure. The advantages this method are: small energy consumption high speeds annealing opportunity of local surface processing details complex configuration, operating in the conditions intensive loads, easy implementation process.
Way of Hardening Surface Coating of Details from Steel 30CrMnSi in Electrolytic Plasma
Authors: Skakov Mazhyn , Zhurerova Laila , Scheffler Michael
Published: December 2012

The present work is devoted research of influence of various modes of electrolytic-plasma cementation on feature of change a structurally-phase conditions and hardening of a constructional steel 30CrMnSi. It is chosen scientifically proved low-power and resources-economy a processing kind which leads to formation stable ferrite-perlites structures, provides higher mechanical properties. Cementation process carried out with selection of different modes of electrolytic-plasma processing in the electrolyte containing water solution of 10 % of sodium carbonate and 10 % of glycerin. As the basic methods of research in work we used metallographic the analysis with microscope application «NEOPHOT-21», X-ray analysis on diffractometer Х’PertPRO in monochromatic CrKα - radiation, tests for microhardness for device PMT-3. It is established that a microstructure of samples steel 30CrMnSi at different modes of processing consist from α - phases, particle carbides. Microhardness of the initial sample makes approximately 3000 МPа, and after processing its microhardness makes 6100 МPа that speaks about of a processing mode. The developed technology of electrolytic-plasma cementation of constructional steels in the conditions of the arc category in electrolyte is the optimal as provides reliable quality and demanded properties of details, working in variable loadings and often exposed to wear, forms the strengthened, modified surface coating.
Fabrication and Properties of Poly(Ether Imide)/Poly(Vinyl Alcohol) Composite Ultrafiltration Membrane
Authors: Chinpa Watchanida
Published: December 2012

A poly(ether imide) (PEI) composite membrane was prepared by dip coating a PEI membrane pretreated with 2-aminoethanole (AEOH) into an aqueous solution of poly(vinyl alcohol) PVA and glutaraldehyde (GA). PEI membrane support was firstly prepared via phase inversion technique by casting a solution of PEI in N-methylpyrrolidone (NMP), using water as non-solvent. The hydrophilicity, permeability, anti-fouling and mechanical properties of unmodified PEI and PEI/PVA composite membranes were investigated. By comparison with the unmodified PEI membrane, the PEI/PVA composite membrane exhibited a higher pure water flux and an increase in its hydrophilicity. In addition, the flux recovery of the pure water flux of the composite PEI membrane was higher than that of the unmodified PEI membrane. This indicated that the obtained composite membrane could reduce the membrane fouling and improve its use for ultrafiltration.
Effects of pH Values on the Structure, Composition and Luminescence of CaWO4:Tb3+ Thin Films
Authors: Chen Lian Ping , Gao Yuan Hong
Published: December 2012

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize Tb3+-doped CaWO4thin films. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that Tb3+-doped CaWO4films have a tetragonal phase. The ratio of n(Tb)/[n(Ca)+n(Tb)+n(Na)] decreases with the increase of pH value of TbCl3solutions. When the pH value (adjusted by NaOH) is higher than 5, Na element has been detected in CaWO4:Tb3+thin films. Based on the analysis on the composition and luminescence, it can be concluded that the pH value of TbCl3solutions must be no higher than 9.1, otherwise, no Tb3+-doped CaWO4thin films can be obtained. Under the excitation of 237 nm, sharp emission peaks at 543 and 489 nm have been observed for Tb3+-doped CaWO4:Tb3+thin films.
Samarium Ions Doped Yttrium Aluminium Garnet Glass Ceramics
Authors: Yang Jie , Liu Xiao , Zhai Bin , Wang Zhi Qiang , Zhao Xin , Lin Hai
Published: December 2012

Sm3+doped YAG glass ceramics containing single phase of YAG micro-crystals have been obtained by heat-treating the aluminosilicate precursor glasses. The YAG crystals grow with several preferred orientations and a dominant one (444) in the matrix, and present microcrystal sizes in the range of 3~15µm. The pilotaxitic texture existed in internal network of the YAG glass ceramics can increase yield strength and tensile strength of the sample effectively. Typical visible transition emissions of Sm3+have been observed in the YAG glass ceramics under the excitation of short-wavelength visible light, and the spectral intensity ratio between the electric dipole4G5/2→6H9/2and the magnetic dipole4G5/2→6H5/2transitions is lower than the values reported in the optical glasses specifying the enhanced symmetric nature in the Sm3+doped YAG glass ceramics. The obvious Stark splitting exhibited in emission spectrum manifests that rare-earth ions have been incorporated into YAG lattices.
Synthesis of Ultrafine SrCO3 Powders by High Gravity
Authors: Zou Xing Wu , Wang Shu Xuan , Yang Zhan Shou , Qi Mi Xiang , Wang Shu Ya
Published: December 2012

A new synthetic technology of Strontium carbonate with high gravity is introduced in this paper. We got ultrafine SrCO3 powders with Sr(NO3)2 and NaCO3 or CO2 as raw material by high gravity method. We studied flows, the rotating speed, additives and CO2 as the reactants on the morphology of strontium carbonate. The results show that the presence of additive-free, we got rod-like structure of strontium carbonate. Added EDTA, we got a good dispersion of spherical particles of narrow particle size distribution. The presence of EDTA, the average particle size of spherical particles decreases with the speed increases. CO2 alternative Na2CO3 as the reactants, the presence of additive-free, we got the bundle structure of strontium carbonate. The presence of EDTA, we got spherical particles, but the particle dispersion is not well, gathered together.
Enhanced Photoelectrochemical Performance of Fe-Doped WO3 Film Electrode under Visible Light
Authors: Cheng Xiao Fang , Feng Hong Wu , Wang Yan Qin
Published: December 2012

WO3 and Fe-doped WO3 thin films were prepared on Indium-Tin Oxide (ITO) glass substrates by a dip-coating. The samples were characterized by photoelectrochemistry, scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis absorption spectroscopy, respectively. The result shows that the doping of Fe influenced absorption performance, and then influenced the catalytic performance. Compared with pure WO3, Fe-doped WO3 exhibited enhanced higher photoelectrochemical(PEC) performance and photocatalytic activity. The effect of doping concentration on the photocurrent was studied. It was found that the photocurrent under visible light displayed the highest values for 2% Fe-WO3 films annealed at 400 °C. The photocatalytic activity of the Fe-doped WO3 was evaluated in the methylene blue(MB) degradation under visible light illumination. The experiments demonstrated that MB could be efficiently degraded using the doped WO3 electrode as the photoanode which showed a higher activity than pure WO3. This provides a novel method for increasing the photon electric conversion efficiency of WO3 thin film electrodes.
Superplasticity of a Ti-48Al-2.3Cr-0.2Mo Alloy
Authors: Zhang Jun Hong , Xu Guo Hui , Xu Ya Juan , He Yue Hui
Published: December 2012

Superplastic behaviors of a Ti-48Al-2.3Cr-0.2Mo alloy with the initial grain size of 0.6m, resulting from 3-steps forging, have been investigated at temperatures ranging from 950°C to 1100°C and at strain rates ranging from 810-5 s-1 to 210-4s-1. The elongations above 500% were obtained at 1050°C-1100°C. An maximum elongation of 566% was obtained at 1050°Cand at a strain rate of 810-5s-1. The flow softening and continuous strain hardening were observed in the curves of true stress-true strain, it is suggested dynamic recrystallization and high-density dislocation caused by pre-deformation are the reasons. By OA, TEM, microstructure evolutions during the deformation were observed. It is found that after superplastic deformation, the grain size become smaller, and the distribution of grain size become more uniform, the densities of dislocations become lower and the dislocations mainly distributed in the areas near grain triple junction. Grain boundary sliding accommodated by dislocation slip is the predominant deformation mechanism.
The Research of Chemical Plating of Pd/Sn on Graphite Anode Surface and its Electro-Catalytic Properties
Authors: Lou Bai Yang , Xu Jian Long , Kong Shui Long , Xu Bin
Published: December 2012

The Pd/Sn catalytic coating on graphite electrode had been synthesized by chemical plating in this paper. Scanning electron microscope(SEM)and Electrochemical workstation(EW)were used to analyze the coating surface topography and electro-catalytic properties of modified graphite electrode with and without the coating. Results show that Pd and Sn are in the form of spherical particle and completely cover the surface of graphite electrode includes concave defects. Most Pd and Sn particles are dispersive ones of size of about 70 nm and few of which are polymerized in island forms. The peak value of current density increases with scanning speed, which goes positive potential scanning. Further more, the peak current increases with the concentration of NaOH solution, which shows nonlinear relationship between peak current and solution concentration, The peak current increases more rapidly with solution concentration increases in low NaOH concentration solution than that in high NaOH concentration solution.
Study on Stealthy Characteristics of Electromagnetic Metamaterials
Authors: Liu Ye , Li Zhu Ying , Zhang Wang Zhou
Published: December 2012

Metamaterials are artificial composite structures or composite materials, which possess supernormal physical properties that natural materials don’t have. Through orderly designing the structures in the critical physical size of materials, we can render the materials to break through some restriction in some certain apparent natural laws. Electromagnetic metamaterials, which have the unusual electromagnetic property of controlling the transmission of electromagnetic wave, are discussed in this paper. Also, forming condition of the metamaterials is testified in theory. In metamaterials, electromagnetic wave could come up to be bending around certain boundary, but its transmission characteristics have no change. According to the superiority of the metamaterials, the metamaterials have the unique military value in the aspect of stealth. And if metamaterials are realized in militarily, it’s no doubt that the possessors will have predominance.
Structure and Properties of a Dimer Complex: [Co(Hdmg)2(Him)2]·(ClO4)
Authors: Liu Xuan Wen , Yuan Shi Hua , Lin Ting Ting
Published: December 2012

A New Complex Crystal [Co(Hdmg)2(Him)2]·(ClO4) (H2dmg = Dimethylglyoxime,Him = Imidazole) Had Been Synthesised in Aqueous Solution and Was Characterized by X-ray Diffraction and IR Spectrum. the Complex Crystallizes in Triclinic Space Group with Cell Constants a= 20.868(7)Å, B=11.408(4)Å, C=15.816(4)Å, α=90.00°, β=116.97(2)°, γ= 90.00°, V= 3355.8(17) Å3, Z=4, F(000)=1732. the Coordination Environment of Cobalt Atom Is a Slightly Distorted Octahedron. the Four Equatorial Donors Are Four Nitrogen Atoms from Two Bidentate Chelate Hdmg Anion Ligands. the Apex Points Are Occupied by Two Nitrogen Atoms from him Ligands. the Co-N(Him) Distance Is 1.930Å, and the Co-N(dmg) Distances Are Varying in the Range from 1.886Å to 1.993Å which Are in Agreement with Corresponding Reported in a Number of other Structurally Related Copper(II) Complexes.
An Investigation on Formation Mechanisms of Wrinkles on Steel Casting Surfaces
Authors: Huang Jin , Xia Lu , Zhang You Shou , Li Si Nian
Published: December 2012

The formation mechanisms of horizontal wrinkles and water wave wrinkles on steel casting surface have been investigated in this study. The horizontal wrinkles, which are the traces of rising steel flow overlapping, are caused by low pouring temperature and slow molten steel flow rising rate. The water wave wrinkles are resulted from the use of an alcohol-based refractory coating with poor permeability and strong penetration behavior. This coating may penetrate deeply into the pores of sand mold and are not easy to be dried by flame combustion. When pouring the alcohol containing in the coating will volatilize and generate a large amount of gas, forming a gas cushion at steel-mold interface. With the gas escapes gradually, the gas cushion disappears, leaving a gap between the steel and the mold, the solidifying casting surface layer will freely fall down and creep in this gap under gravity itself, resulting in casting surface wrinkling.
Structure and Magnetic Properties of (Al, Co) Co-Doped ZnO Thin Films
Authors: Cao Ping , Bai Yue
Published: December 2012

In this study, Zn0.99Co0.01Al0.015O thin film has been prepared by sol-gel method. The structural and magnetic properties of the sample were investigated. X-ray diffraction spectroscopy analyses indicate that the Co and Al codoping can not disturb the structure of ZnO. No additional peaks are observed in the Zn0.99Co0.01AlxO and Al3+ and Co2+ substitute for Zn2+ without changing the wurtzite structure. The resistance measurements confirm that Al ions increase the free carriers concentration. Based on the above experiments we think the ferromagnetic behavior of the sample could not originate from Co nanoclusters. The presence of free carriers and localized d spins is a prerequisite for the appearance of ferromagnetism. As the result, the carriers generated by Al doping is considered a main factor to induce the ferromagnetic phenomenon.
Effects of Na+ on Spectral Properties of Er3+: CaF2 Transparent Ceramic
Authors: Li Wei Wei , Mei Bing Chu , Li Xiaonv , Song Jing Hong , Zhi Guang Lin
Published: December 2012

Er3+, Na+-co-doped CaF2 transparent ceramics with Er3+ dopant concentration of 5at% and Na+ of 0, 0.5, 1.0 and 1.5at% were fabricated by the vacuum hot pressing method. Absorption spectra, emission spectra and fluorescence lifetimes were measured at room temperature to study the effects of Na+ on the spectral properties of Er3+: CaF2 transparent ceramic. The results showed that after introducing Na ion into Er3+: CaF2 transparent ceramics, charge-neutralized Er3+-Na+ structure formed which prevented Er3+ from clustering, the absorption intensity of ceramics decreased with the increase of Na+ concentration, but the spectroscopy and photoluminescence properties of Er3+ in CaF2 transparent ceramic could be modulated by adjusting the concentration of Na+. Co-doping Na+ to increase fluorescence lifetime should have an optimal value.
Synthesis and Properties of New Biodegradable Polyurethane Containing Natural Rubber and Poly(lactic Acid): Effect of NR and PLA Ratio
Authors: Khaokong Chuanpit , Suwanmanee Jinwara , Pilard Jean François , Pasetto Pamela , Tanrattanakul Varaporn
Published: December 2012

Biodegradable polyurethane was synthesized using poly(DL-lactic acid) diol and hydroxytelechelic natural rubber as hydroxyl containing precursor, 1,4-butane diol as chain extender, isophorone diisocyanate and dibutyltin dilaurate as catalyst. Poly(DL-lactic acid) diol was prepared by condensation polymerization of DL-lactic acid using 1,4-butane diol as initiator and stannous octoate as catalyst. Hydroxyltelechelic natural rubber synthesized via oxidative degradation of natural rubber and then reduced carbonyl end group to hydroxyl group. Chemical structure of products was characterized by 1H-NMR. Molecular weight and polydispersity determined by SEC. Thermal properties was characterized by DSC and TGA. Segmented polyurethane show two Tgs and two degradation steps corresponding to natural rubber and poly(DL-lactic acid) segment. Polyurethane containing poly(lactic acid) more than 40%mol are become brittle. This result caused by brittle characteristic of PLA. Moreover, mechanical properties increased as content of PLA increased.
New Usage for Cyclotrimerization Reaction: A Facile Synthesis of 1,3,5-Triazine Derivatives
Authors: Ouyang Mi , Yu Chun Hui , Zhang Ning Yu , Song Qing Bao , Sun Jing Wei , Hu Bin , Zhang Cheng
Published: December 2012

Series of star-shaped molecules based on 1,3,5-triazine core have been synthesized via CF3SO3H-mediated cyclotrimerization reaction, and then characterized by 1H-NMR, 13C-NMR, MALDI-TOF-MS, and elemental analysis. The effects of different factors, such as the steric hindrance and electronegativity on the reaction efficiency, are systematically studied. The results indicate that the steric hindrance plays an important role in the reaction, while electronegativity has little impact on this reaction. In addition, the bridges including ethylene group and carbon atom between 1,3,5-triazine core and peripherals are firstly studied in this work, which expands the application of CF3SO3H-mediated cyclotrimerization reaction. Moreover, we have successfully broadened the cyclotrimerization reaction to the preparation of 1,3,5-triazine derivatives with different substituents as the peripheral, which is promising for preparation of single-layer multi-functional optoelectronic materials.
Preparation and Characterization of Thermoplastic Starch/Wheat Gluten Composites
Authors: Kaewtathip Kaewta , Tanrattanakul Varaporn , Kaewtathip Thipthida
Published: December 2012

Thermoplastic starch (TPS) and TPS/wheat gluten composites were prepared using compression molding. The wheat gluten contents ranged from 0 wt% to 20 wt%. The morphology of the fractured surfaces, thermal decomposition temperatures and mechanical properties of the TPS and TPS/wheat gluten composites were investigated using scanning election microscopy (SEM), thermal gravimetric analysis (TGA) and tensile testing, respectively. The maximum tensile strength of TPS/wheat gluten composites (1.1 MPa) was obtained when 10 wt% of wheat gluten was used. The crosslinking between wheat gluten protein chains caused an increase in the tensile strength of the TPS/wheat gluten composites. The temperature at the maximum weight loss of the TPS/wheat gluten composites was higher than for TPS. Moreover, wheat gluten decreased the water absorption.
Thin Films of Liquid Crystalline Phthalocyanines and their its Composites with Single-Walled Carbon Nanotubes: Properties and Alignment
Authors: Basova Tamara , Esenpinar Aliye Aslı , Tuncel Sinem , Durmuş Mahmut , Gürek Ayşe Gül , Ahsen Vefa
Published: December 2012

In this study, liquid crystalline copper phthalocyanine and single walled carbon nanotubes were dispersed in solution to prepare novel composites. Thin films of these composites prepared by solving of the composite in dimetylformamide and then by spin coating the solution onto the substrates were studied by the methods of polarizing microscopy, polarized Raman and optical absorption spectroscopies. It was shown that pure CuPcR4forms the films with a herringbone arrangement of phthalocyanine molecules within adjacent columns. An addition of carbon nanotubes (0.5-2 wt %) to CuPcR4leads to formation of the films with edge-on orientation of the molecules. The higher conductivity values were found for the films of phthalocyanine containing SWCNT. The lateral conductivity tends to decrease with the increase of SWCNT concentration from 0.5 to 2 wt %.
Adhesion Performance and Wear Resistance of Multilayered TiN Coating Deposited by Hollow Cathode Discharge Method
Authors: Yu Zhi Ming , Hu Jia Xiu , Niu Yun Song , Wei Jie , Yang Ying
Published: December 2012

Multilayered TiN coating was successfully prepared by hollow cathode discharge method. By introduction of the multilayered microstructure, the columnar epitaxial growth of TiN grains was obviously suppressed. The hardness, adhesion performance and wear resistance of the multilayered TiN coating were compared with those of the ordinary TiN coating. The wear resistance of the multilayered TiN coating is much better than that of the ordinary TiN coating. It is due to the multilayered microstructure of the coating that pileups the dislocations and also inhibits the bulk-flaking behavior for the multilayered TiN coating. The morphology analysis of cross section shows that the wear mechanism of the multilayered TiN coating is the micro-area detachment. Moreover, the adhesion of the TiN coating to the substrate is greatly enhanced by the microstructure optimization of the coating.
Comparison of Two Methods of Solving Electromagnetic Parameters of Metamaterials with the Unit Cell of Symmetrically Arranged SRRs
Authors: Zhang Wang Zhou , Li Zhu Ying , Liu Ye
Published: December 2012

Based on the principle that metamaterials-composite structured materials, in which permittivity(ε)and permeability(μ)are both negative in some frequencice, can be structured with periodically arranged SRRs and thin metallic wires which have negative effective permeability and negative effective permittivity respectively, the circular structure of SRRs was modified and a new split-ring resonator with symmetric structure was proposed. A detailed description of the design and simulation procedure was given simultaneously. According to the pattern of symmetric SRRs, ε and μ were calculated in analytic formula. Furthermore, metamaterials with symmetric SRRs was simulated with the software ANSOFT, and electromagnetic parameters were retried from S parameter. From analytic result and the retrieval result of electromagnetic parameters, left-handed behavior was obvious in a specific frequency range and the permittivity, the permeability and the index of refraction are all negative.
Effect of Doped Manganese Oxide on the Properties of Ce0.8Gd0.2O2-δ Solid Electrolyte
Authors: Zhang Zhi Juan
Published: December 2012

The effects of Ce0.8Gd0.2O2-δ (CGO) doped manganese oxide as sintering additive on density and conductivity were studied. The experimental results indicated that relative density of CGO doped 2.0 mol% MnO1.333 (2Mn-CGO) increased within a certain temperature range because of the occurrence of viscous flow sintering, it was 89.5% at the sintering temperature of 1100 oC and higher 6.8% than that of CGO. Moreover, it can reach 91.1% for 2Mn-CGO at the sintering temperature of 1200 oC. The conductivity measured at 700 oC of 2Mn-CGO sintered at 1100 oC was 4.52×10-2 S/cm, which is higher than that of CGO. The value of 2Mn-CGO with the sintering temperature of 1200 oC was 5.24×10-2S/cm, which dropped slightly than that of CGO, this was caused by blocking of the migration of carriers.
Preparation and Mechanical Properties of C/SiC Joints with Pins or Bolts
Authors: Li Guang De , Zhang Chang Rui , Hu Hai Feng , Zhang Yu Di , Chen Si’an , He Xin Bo , Mei Min
Published: December 2012

C/SiC substrates and M3 bolts were prepared by precursor infiltration and pyrolysis (PIP) process firstly, then the joints with four joining methods (2 φ3mm soft pins, S-A; 2 M3 bolts, S-B; 2 φ3mm soft pins plus 8 φ1mm soft pins, S-C; 2 M3 bolts plus 8 φ1mm soft pins, S-D) were assembled, finally several PIP cycles were continued to finish densification. The influences of different joining methods and PIP cycles (3 or 6) on the stripping properties of C/SiC joints were investigated, and the fracture modes were analyzed. The stripping loads of the joints adopting 6 PIP cycles are almost two to six times the values adopting 3 PIP cycles, and the corresponding fracture modes are pins or bolts rupture and pull-out, respectively. When adopting 3 PIP cycles, the bearing ability of the joints with bolts (S-B and S-D) is about 51% higher than that of joints with pins (S-A and S-C), but when adopting 6 PIP cycles, the values with pins (S-A and S-C) is about 67% higher than that with bolts (S-B and S-D). Besides, the introduction of φ1mm pins enhances the bearing ability of the joints with 3 and 6 PIP cycles about 45% and 14%, respectively.
The Formaldehyde OTFT Sensor Based on the Airbrushed P3HT/ZnO Composite Thin Film
Authors: Dan Wen Chao , Jiang Ya Dong , Tai Hui Ling , Xie Guang Zhong , Li Xian , Fu Chang Jie , Wu Ze
Published: December 2012

The pure conducting polymer P3HT film is less sensitive to the formaldehyde (HCHO), and the pure ZnO film needs a high temperature to militate the HCHO, as a result, the P3HT/ZnO composite was fabricated on the organic thin film transistor (OTFT) by spraying to detect the HCHO at room temperature, the electrical properties and sensing properties of all the prepared OTFT devices were measured by Keithley 4200-SCS source measurement unit. What is more, the effect of different P3HT/ZnO composite masses on the response of sensors were tested, all the sensors showed a remarkable response to HCHO, and the optimized composite mass of 1.0ml was obtained. Since most detecting methods for the HCHO vapor require an high temperature, the experiments and results in this paper showed the important significance for the field of HCHO detecting.
Study on Novel Structure of Glycolic and Oxalic Acid Holmium: [Ho (C3 H6O9)]·CH3OH
Authors: Liu Hai Xing , Zeng Wu Lan , Xiao Jing Zhong , Zeng Guang , Yue Hui Juan , Tai Xi Shi
Published: December 2012

In the study of functional materials, more attention is the construction of organic–inorganic hybrid materials with structural diversity, fascinating properties, and potential applications in catalysis, molecular adsorption, medicine, electro-conductivity, magnetism and photochemistry. At present, the research work in upconversion emission in rare-earth doping materials has been greatly increased. Yb3+ and Ho3+ upconversion energy transfer is attractive, because Yb3+ and Ho3+ upconversion energy transfer is relatively simple compared to upconversion involving other rare-earth ions. In this paper, a novel holmium complex [Ho (C3 H6O9)] •CH3OH has been synthesized from a hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Ho atom is coordinated by eight O atoms. The molecular is antisymmetric structure by the C2-C2 axis. The molecular structure stabilized by the O-H…O hydrogen-bonding interactions.
Model of Predicting Polymer Melt Temperature Field by BP Neural Networks
Authors: Li Meng Shan , Liu Bing Xiang , Wu Yan
Published: December 2012

Temperature of the polymer melt is one of the most important parameters for the polymer continuous extrusion molding process. There are many factors influence the distribution of the melt temperature, these factors have the coupling and nonlinear relationship which is difficult to measure accurately by the traditional measuring method. In this study, a BP neural networks-based model approach is presented in which the effects of the die wall temperature and screw speed and the wall temperature of the transition section and the measurement section in the continuous extrusion molding are investigated. Comparison of the BP neural networks model predictions with the experimental data yields very good agreement and demonstrates that the BP neural networks model can predict the polymer melt temperature field with a high degree of precision (the mean square error within 0.03)