bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Different Post-Treatment on the Morphology, Structure and Property of Electrospun SF Nanofiber Mats
Authors: Liu Tao , Zhang Feng , Zuo Bao Qi
Published: July 2012

In this paper, we employed Methanol, 75% Ethanol, 100%Ethanol, and Isopropanol to treat electrospun SF nanofiber mats, and studied the morphology, structure and property of SF nanofiber before and after treatment by means of SEM, and FTIR. While the as-spun SF nanofiber mats consisted of α-helix and random coil, post-treatment of the SF nanofiber resulted in significant increase in β-sheet component and improvement of water resistance of the SF nanofiber mats. This effect was not obvious affected when different post-treatment system was used, but methanol and 75% was more effective in inducing conformation transition from α-helix and random coil to β-sheet.
Self-Assembly Behavior of N-Methly-N-Hexadecyl-Pyrrolidinium Bromide in Water
Authors: He Jin Hua , Li Cui Hua , Qian Lian An , Liu Jian Hong , Zhang Qian Ling
Published: July 2012

N-methyl-N-hexadecylpyrrolidinium bromide (IL) was synthesized for the design of ionic liquid crystals which is a fascinating class of molecular materials, offering the combination of order and mobility. In binary mixtures with water, lyotropic liquid crystalline phase appears in the range of IL content from 35% to 70% and the temperature range from -1.1 to 24 °C in the heating run. The SAXS curves explored the self-assembly processes and hexagonal phase of the IL apparent sol. The saturated aliphatic ionic liquid in water assemble less tightly compared with aromatic ionic liquid based on imidazolium in water, which is due to the absence of aromatic package effect.
Preparation of Uniform Microcapsules Containing Ionic Liquid for Caprolactam Extraction
Authors: Chen Dong Xuan , OuYang Xiao Kun , Wang Yang Guang , Yang Li Ye , Yu Di , He Chao Hong
Published: July 2012

Microencapsulating ionic liquid is an effective way to overcome the loss of ionic liquid in the extraction process. A phase inversion method was used to form microcapsules containing 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF6]. The oil phase, composed of [BMIM][PF6], polysulfone and dichloromethane, was dropped into the 0.2 wt% gelatin aqueous solution using nitrogen gas pressure to form droplets. As dichloromethane evaporated completely, polysulfone microcapsules containing [BMIM] [PF6] were obtained. The microcapsules were characterized using a polarizing microscope, a laser particle size analyzer and a thermogravimetric analyzer. Moreover the microcapsules were performed some effect on caprolactam extraction from water.
Performance Optimization of Nanotubes Prepared by a Template Synthesis Method
Authors: Zheng Hua Jing , Cheng Shi Jun , Jiang Ya Dong , Xu Jian Hua
Published: July 2012

PEDOT nanotubes were prepared by a template synthesis method. Based on our template, it was deduced that there are two successive processes in the formation of nanotubes. The first step is soakage of the porous templates by a polymer solution, and the second step is adsorption of free charged cationic groups and doped PEDOT onto the template surface with negative charges. XRD results showed that well orientated PEDOT chain were formed during the synthesis, moreover the arrange conductivity of molecular chains strongly affect the structures of PEDOT nanotubes. The nanotubes were measured to be about 5.5~17.6 S/cm, which is higher than that of nanotube pellet due to the high contact resistance between the adjacent nanotubes.
Sorption of Atrazine (AT) on Nano-SiO2 and Nano-Kaolinite
Authors: Lu Jia Juan , Xia Xun Feng , Yan Xiao Min , Wang Dong Sheng , Fan Qing Ru
Published: July 2012

With the increasing use of nano-SiO2and nano-kaolinite, it is imperative to investigate their effect on the transport of aqueous contaminants. In this study, the extent and reversibility of sorption of AT on nano-SiO2and nano-kaolinite were examined using batch sorption experiments. Influence of ionic strength, pH and temperature was investigated. Sorption data were well fitted with Freundlich models. The sorption capacities were larger at low ionc strengths and low pHs. Nano-particle aggregate size is an important factor for the pH influencing process, which increase as the pH approach pHzpc. The sorption of AT on the two nano-particles is spontaneous.
An Innovative Method to Reduce Percolation Threshold of Carbon Nanotubes Filled Nylon6/Polystyrene Blends
Authors: Lu Chang , Huang Xin Hui , Wang Jia Xi , Hu Xiao Ning
Published: July 2012

Selective localization of carbon nanotubes (CNTs) at the interface of immiscible polymer blend was achieved by the method that poly(styrene-co-maleic anhydride) (SMA) was first reacted with CNTs, and then blended with nylon6/polystyrene (PA6/PS). In the PA6/PS blends, CNTs was localized in PA6 phase and the percolation threshold was 2wt%. However, for the PA6/PS/(SMA- CNTs) composites, TEM results showed that most of CNTs were selectively localized in matrix, but some of tubes were induced by SMA to disperse at the interface. The localization of CNTs at the interface caused the percolation threshold of PA6/PS/(SMA- CNTs) was only 0.33 wt%, which is much lower than that of PA6/PS/ CNTs.
A Facile Synthesis of DNA-Magnetic-Fluorescent Composite Particles
Authors: Wang Miao , Xu Si Yuan , She Yong Xin , Jin Mao Jun , Jin Fen , Shao Hua , Wang Jing
Published: July 2012

A simple and convenient method to make a novel material of DNA-coated magnetic-fluorescent composite particles was presented in this article. Hydrothermal synthesis was used for obtaining Fe3O4 magnetic nanoparticles. After modified by oleic acid, the nanoparticles were coated by the macromolecular shell, which came form the polymerization of ethyleneglycol dimethacrylate and methacrylic acid. With the help of ethylenediamine as linker molecules and the condensation effect of ethyl (dimethylaminopropyl) – carbodiimide and N-Hydroxysuccinimide (EDC/NHS) reaction system, salmon DNA were linked to the surface of the shell. After labeling a fluorescent dye Syber Green Ⅰ®, the magnetic-fluorescent composite particles were produced.
Spin-Glass Behavior and the Magnetic Relaxation Effects in Nd0.90Sr0.10CoO3
Authors: Yang Yi Yun
Published: July 2012

The magnetization, ac susceptibility and magnetic relaxation of Nd0.90Sr0.10CoO3polycrystalline sample were systematically investigated in this paper. The experimental studies of susceptibility and magnetic relaxation evidence the existence of a low-temperature spin-glass. A dynamic analysis of ac susceptibility implies a spin-glass transition temperature TSG =12.17 K and the dynamical exponent zv=8. Moreover, low-temperature zero-field cooling and field cooling magnetic relaxation show perfectly mirror symmetry, and field cooling processes relaxation obeys a stretched exponential form. Therefore, our study confirms that the phase separation in Nd0.90Sr0.10CoO3originates from both the ferromagnetic clusters interaction and the spin glasslike phase at low temperature.
Strong Green PL Emission of Sol-Gel Derived Tb3+-Ce3+ Ions Co-Doped SiO2 Matrix Nanocomposites
Authors: Wang Yi , Zhang Hong , Zhang Kun
Published: July 2012

Tb-Ce ions co-doped SiO2 matrix nanocomposites were prepared successfully by a modified sol-gel method. High resolution SEM shows that the dried sample (annealed at 120°C for 48 hours) was in a “magnetic-domain” like structure. When the sample was treated at high temperature (800°C for 3 hours), it really forms an amorphous glass state with average grain size of 49.8nm. Under the excitation of 257nm UV light, the very strong emission of green light are observed around 544nm (5D4 - 7F5). The possible mechanism of efficient energy transfer occurred in SiO2:Ce3+-Tb3+ phosphor is from Ce3+ to Tb3+. Various mole ratio of Tb:Ce and their concentrations, different annealing temperature and time have significant influence on PL properties of Tb-Ce ions co-doped SiO2 matrix nanocomposites.
Morphology and Dielectric Property of Cellular Polyimide Films Prepared by Phase Inversion
Authors: Chu Hui Juan , Wei Hong Liang , Zhu Jing , Zhu Bao Ku , Xu You Yi
Published: July 2012

In order to explore low dielectric polymeric materials, two types of cellular polyimide films with different dianhydride units were prepared by phase inversion method, and their dielectric properties were investigated. Polyimide films with various cellular structures were obtained by controlling coagulation bath compositions and temperatures. The effects of chemical structures, cellular structures on dielectric property of cellular polyimide films were studied. The results showed that all of the cellular polyimide films had lower dielectric constants than the polymer matrix. The dielectric properties were influenced dominantly by the morphologies of the films. Cellular Polyimide films filled with uniform small cellular structures behaved excellent dielectric property compared with those large-pore cellular films. These findings would provide potential application for cellular polyimide films in microelectronic devices.
Preparation of Magnetic Polyglycidyl Methacrylate Microspheres
Authors: Jiang Shu Juan , Lin Xin Ping , Zhou Lei Ji
Published: July 2012

We present an approach of synthesizing magnetic polyglycidyl methacrylate (PGMA) microspheres by a simple method of dispersion polymerization. Water-based Magnetic fluids which have different surface properties disperse in reaction system. The magnetic microspheres are appropriate to construct liquid chip carriers. In this work, citric acid-modified and citric acid sodium-modified magnetic nanoparticles for the preparation of magnetic microspheres are investigated. SEM results indicated that the magnetic microspheres have an average diameter of 3.78 μm with excellent monodispersity (PDI 1.09). Magnetization curve of Fe3O4 nanoparticles using superconducting quantum magnetometer showed their good performance in magnetic response characteristics. Chemical structures and crystal form of magnetic Fe3O4 were characterized and analyzed using FT-IR and XRD methods.
A Study on the UV- and Thermo- Stability of Organosilane-Functionalized Carbon Dots Films
Authors: Wang Wen Tai , Kim Tak Hyun , Yan Zi Feng , Tade Moses.O. , Li Qin
Published: July 2012

In this work, high quantum yield nanodots were produced by using an organosilane as a coordinating solvent and fabricated the product into solid films. In order to assess the practicality as a material for optoelectronic device, solid state properties were analyzed extensively including UV stability and thermal stability.
The Hydrothermal Synthesis of β-ZnMoO4 for UV or Visible-Light-Responsive Photocatalytic Dedradation of Victoria Blue R
Authors: Chen Chiing Chang , Jiang Yu Rou , Chang Ken Hao
Published: July 2012

In this study, hydrothermal reaction with Na2MoO4 and Zn(NO3)2as a precursor were investigated for the synthesis of β-ZnMoO4. The β-ZnMoO4were characterized by the X-ray diffractometer (XRD), electron microscopy with the field emission scanning electron microscopy with energy dispersive X-ray spectrometer (FE-SEM-EDS), high resolution X-ray photoelectron spectrometry (HR-XPS), UV-vis diffuse reflectance spectrometry (UV-DRS), and Fourier transform infrared spectrometry (FT-IR). Diffuse UV-vis spectra show the β-ZnMoO4materials to be indirect semiconductors with an optical bandgap of 2.48-2.64 eV. The photocatalytic efficiencies of powder suspensions were evaluated by measuring the Victoria Blue R (VBR) concentration. This is the first reveal that excellent activities of β-ZnMoO4are a promising visible-light-responsive photocatalyst.
Numerical Simulation Analysis on Lengthwise Graphitization Furnace Co-Production Silicon Carbide
Authors: Li Yong Gang , Hu Yang Dong , Wu Lian Ying , Yu Chun Li
Published: July 2012

The effective thermal conductivity coefficient of silicon carbide (SiC) synthesis materials and graphitization furnace insulation material were obtained by applying heat percolation theory and thermal coefficient equation of various layer-compositors. This paper proposed a further numerical analysis on the temperature distribution of SiC furnace, lengthwise graphitization (LWG) furnace and Co-production furnace by open source finite element software FEPG. The results show that the Co-production furnace can produce SiC after finishing graphitization production and Co-production furnace’s energy consumption subtract energy consumption of LWG furnace, SiC production energy consumption of Co-production furnace is half and SiC yield of Co-production furnace is 57-73 percent of same type of SiC furnace. Besides, applying Co-production process could reduce the exhaust of whole LWG furnace.
Preparation and Properties of a Novel Ash-Calcium-Powder Internal Wall Coating
Authors: Cheng Shao Juan , Liu Shao Bing , Wang Xiao Feng , Fu Xin Jian
Published: July 2012

A kind of novel ash-calcium-powder internal wall coating was successfully prepared. The stability problem was resolved by adding the stabilizer synthesized in our own laboratory. The effect of vinyl acetate ester-ethylene (VAE) emulsion contents on the property of scrub resistance was studied. And the effect of ash-calcium-powder contents on the property of scrub resistance and contrast ratio were discussed. The results indicate that the scrub resistance increase with increasing the content of ash-calcium-powder or VAE emulsion. Also the scrub resistance is effected by the filming time. And it is shown that the longer, the better the scrub resistance.
The Effect of Modified Straw on Microstructure of Soil Consolidation Material
Authors: Yan Liang , Zhang Xiu Li
Published: July 2012

The application of wheat straw fiber reinforced cement-based composites (WFCC) was restricted because of the poor mechanical properties and lots of extractives of wheat straw in cement paste. In order to overcome the natural defects, the wheat straw was modified respectively by different mass fractions of NaOH, Na2SiO3and H3PO4solutions. The results show that, the various indexes of wheat straw fiber soaked by NaOH solutions (mass fraction 5%) for 12 hours were optimal. Moreover, its ultimate tensile strength and fracture elongation were respectively increased by 104.81% and 78.57%. Meanwhile, the modified fiber bundles arranged densely without damage phenomenon in WFCC, and surface of fiber was covered in massive cement hydration products, and the interfacial adhesion between fiber and hardened cement paste was improved.
Sintering Behavior and Microwave Dielectric Properties of 95MCT Ceramics Prepared from Different Size Powders by Sol-Gel Method
Authors: Fang Yi Hang , Miao Kai , Feng Si Qiao , Cao Jia Meng , Wang Huan Ping , Xu Shi Qing
Published: July 2012

The 0.95MgTiO3-0.05CaTiO3 (95MCT) powders and ceramics were prepared by a sol-gel method by using Mg(NO3)2•6H2O, Ca(NO3)2•4H2O and Ti(C4H9O)4 as the starting materials. The effects of calcination temperature on phase formation, morphology and particle size distribution of the proposed powders were examined, and the microwave dielectric properties of 95MCT ceramics made from different size particles were investigated. The dried gels were calcined at 600 °C, 700 °C, 800 °C and 900 °C, and the derived particle sizes of powders were 10-20 nm, 50-100 nm, 60-120 nm and 120-150 nm, respectively. The proper sizes, which range from 50-150 nm, lowered the sintering temperature of 95MCT ceramics effectively from 1400 °C to 1175 °C due to the high surface energy. Sintered at 1175 °C, the 95MCT ceramic prepared from 50-100 nm size particles had compact structure and exhibited good microwave dielectric properties: εr = 21.33 and Q×f = 36,315 GHz.
Effects of RE on Microstructure and Mechanical Properties of Low-Alloy Steel
Authors: Liu Xiao , Li Zhi Hui
Published: July 2012

The effect of rare earth element on structure and mechanical properties of SS400 steel were studied by metallographic examination, scanning electron microscope (SEM), tensile test and impact test. The results show that rare earth can refine microstructure of SS400 steel. Fracture is changed from cleavage to ductile fracture by adding RE to SS400 steel. And the mechanical properties of SS400 are improved. The impact toughness value of SS400 steel (containing 0.02 RE) increases by 39.66% at -40°C, and at 0°C the impact toughness value increases by 31.05%, respectively comparing with that of steel without RE.
Application and Mechanism Study of a Novel Copolymer for Filter Aids on Wet-Process Phosphoric Acid
Authors: Du Guang Chao , Fei De Jun , Wu Jian Xun , Dang Ya Gu , Liu Yong , Xu Jie
Published: July 2012

A novel copolymer PADA which has two functions of flocculation and surface activity was synthesized in aqueous solution. The copolymer was applied to filtration aiding on wet-process phosphoric acid (WPA). The results show that PADA can increase the filtration rate of the phosphoric acid slurry and decrease the moisture of the filter cake. The mechanism of filtration aiding was studied. PADA neutralizes the surface potential of the phosphogypsum and makes the microcrystal particles flocculate to conglobation, which indicate that electrostatic neutralization and flocculation might be the action modes in the process of filtration aiding. The shortest flocculation time and largest average diameter of floccules can be obtained with the addition of 10 ppm PADA. The average pore size and porosity of the filter cake are enlarged by 0.22 μm and 15.38% respectively with the addition of PADA. The surface contact angle of the phosphogypsum is increased by 3.4° with PADA presence.
Research on the Influence of Stiffness of Copolymer(N-Tert-octylacrylamide/Acrylic acid/Methyl methacrylate/Butylaminoethyl Methacrylate/Hydroxypropyl Methacrylate) by Methyl Methacrylate and N-Tert-Octylacrylamide
Authors: Zhu Jie , Xiao Weng Fa , Dong Li Tao , Teng Fei
Published: July 2012

The copolymer had been synthesized by using N-tert-octylacrylamide/Acrylic acid/Methyl methacrylate/Butylaminoethyl Methacrylate/Hydroxypropyl Methacrylate as monomers.By adjusting monomers ratio,N-tert-octylacrylamide or methyl methacrylate,futher study the influence on the stiffness of the copolymer and the relationship beween monomers ratio and the stiffness.
Development of Outlast Fiber and Study about its Character of Thermoregulation
Authors: Zhang Yong Fang , Sun Bu Kun
Published: July 2012

On the ground of its development and thermoregulation theory, thermoregulation property of Outlast fiber was subjected to test and analysis by means of thermal analysis. Specifically over the applied sample of Outlast acrylic fiber, it was concluded by test that the ranges of fusion heat absorption and crystallization heat release were 22.11°C～25.84°C and 27.45°C～20.07°C, peak temperatures of heat absorption and release were 25.84°C and 20.07°C, and enthalpy data of fusion & crystallization were 7.887J/g and 9.667J/g respectively. Outlast fiber, therefore, has been certified its obvious capability of temperature regulation, as a foundation for further study in the future.
Studied on Preparation Montmorillonite Modified by CTAMB and Adsorption Performance on Nitrobenzene
Authors: Liu Si Man , Yan Bin Ba , Wang Pin
Published: July 2012

Na-montmorillonite was modified by CTAMB through the intercalation. The effects of amount, temperature, time on microstructure were characterized by X-ray diffraction; Fourier transforms infrared spectrometer, and N2adsorption isotherms. At same time, the adsorption performance on the nitrobenzene was compared by UV-visible absorption spectra. The results show that: CTAMB can effectively increase the crystal spacing of sodium montmorillonite. The reaction time and reaction temperature has little effect on the reaction process. The modified montmorillonite by CTAMB can adsorption nitrobenzene, and its adsorption properties relate with the crystal spacing. At the same time pore volume of modified montmorillonite can be increased, it is beneficial to the adsorption of nitrobenzene. Compare with OTAC, the pore radius of montmorillonite modified by CTAMB is smaller.
Effect of Post-Deposition Annealing on some Optical Properties of Thermally-Evaporated V2O5 Thin Film
Authors: Aly S.A.
Published: July 2012

A Vanadium Pentoxide Sample with a Film Thickness of 75 Nm Has Been Thermally Evaporated on Unheated Glass Substrate Using V2O5High Purity Powder. the Sample Was Subjected to a Subsequent Post-Deposition Annealing in Air at Different Temperatures for a Period of One Hour. the Optical Properties Were Studied by Transmittance and Reflectance Measurements. the Integrated Visible ,TVis, and Solar, TSol, Transmittance Were Calculated. the Spectral Behaviour of the Refractive Index as Well as the Absorption Coefficient before and after Post-Deposition Heat-Treatment Was Also Reported. X-Ray Diffraction Confirmed that the Film in the as-Deposited as Well as after Annealing up to 400 °C Is in the Amorphous State.
Effect of Hydrogen on the Microhardness of Tin Brass Heat Exchanger Tube
Authors: El-Amoush Amjad Saleh
Published: July 2012

Tin Brass Heat Exchanger Tube Was Hydrogen-Charged under Various Cathodic Charging Conditions. the Introduction of Charged Hydrogen into Tin Brass Tube Was Found to Induce Hardening of its Surface. the Severity and the Depth of the Hardened Region Was Observed to Increase with either Cathodic Current Density or Charging Time. Ageing after Charging Results in either Complete or Partial Recovery of Hardness, Depending upon the Charging Conditions Applied to the Heat Exchanger Tube.
Artificial Ageing Effect on Mechanical, Electrical Properties and Positron Lifetime of Aircraft 2024 Alloy
Authors: Refaey Abdullah A. , Abdel-Rahman M. A. , Badawi Emad A.
Published: July 2012

Heat Treatments for Different Aging Times Were Performed on 2024 Aluminum Alloy. the Effect on the Positron Lifetime, Electrical and Mechanical Properties of the 2024 (Al-Cu-Mg) Alloy Was Studied. Artificial Ageing Was Conducted by Heating at a Constant Rate to a Specific Temperature, Followed by Annealing. the Alloy Was Treated at 192°C for Various Times, Followed by Annealing. Measurements as a Function of Aging Time Were Found to Exhibit Prominent Changes Related to the Formation of Precipitates.
Microwave Sintering of ZrO2 Fiber-Reinforced Hydroxyapatite Matrix Composites
Authors: Ehsani N. , Ruys A.J. , Sorrell C.C.
Published: July 2012

PSZ (ZrO2 Fiber)-reinforced HAp was sintered using conventional and microwave hybrid heating. Microwave heating cycles were ~50 times faster than conventional sintering cycles and enabled the use of reduced densification temperatures and soak times by as much as ~100°C and 55 min, respectively. However, although there was a significant improvement in densification levels attainable before decomposition, the improvements were insufficient to produce near-fully or fully dense samples. However, the promising gains made suggest that microwave hot pressing would be a suitable area for future work. Keywords: Hydroxyapatite, microwave sintering, fibre-reinforced ceramics, bioceramics, zirconia fibre
A Nanoscale Surface Structure Removal Process Using Excimer Irradiation and a Cross-Shaped Electrode Tool
Authors: Pa P.S.
Published: July 2012

A Newly Designed Cross-Shaped Electrode Tool and the Use of Excimer Irradiation to Assist in Micro-Electrochemical Etching (μ-ECE) Is Presented. It Is a Precise Surface Treatment Method for the Nanoscale Removal of Defective Indium-Tin-Oxide (In2O3SnO2) Conductive Nanostructure from Optical PET-Diaphragms (PET) of Digital Paper Touch-Panels. in the Current Study, 172nm Excimer Irradiation Is Used to Boost the Electrolytic Action of the Cross-Shaped Electrode Tool. Scoring of the PET Surface Is Eliminated and the Workpiece (PET) Feed Rate Can Be Higher with a Consequent Reduction in Production Costs. when Excimer Irradiation Is Used the In2o3sno2 Thin-Films Are More Easily Broken up and the Nano-Particles Escape from the PET Substrate Quickly and Cleanly. The Required Machining Time Is Shortened if Excimer Irradiation Is Used before the Electrochemical Removal Processing (μ-ECE) of the In2O3SnO2 Layer.
Arsenic Sulphide As4S4 Nanoparticles: Physico-Chemical Properties and Anticancer Effects
Authors: Baláz Peter , Sedlák Ján , Pastorek Michal , Cholujová Danka , Vignarooban Kandasamy , Bhosle Siddhesh , Boolchand Punit , Bujňáková Zdenka , Dutková Erika , Kartachova Olga , Stalder Bernhardt
Published: July 2012

In this study, arsenic sulphide As4S4nanoparticles have been prepared, by high-energy wet milling, in the presence of sodium dodecylsulphate, which acts a surfactant. Solid state properties of the nanoparticles were characterised by XRD, Raman scattering, specific surface area and particle size distribution. Changes in surface areas of the particles, in the 0.2 - 5.4 m2g-1range, and nanosize distributions, in the 100 - 250 nm range, characterise the surface and morphological properties of nanorealgar. Raman scattering revealed various species in the milled sample that indicate a disproportionate reaction (3As4S4→ 4As2S3+ 4As) occurring as a consequence of milling. Anticancer effects, of the milled species, were confirmed for the human multiple myeloma U266 and OPM1 cell lines. Dissolution experiments in simulated gastric fluid show a possibility for the application of the realgar nanoparticles as an oral dose in future arsenic drug cancer treatments.
The Deposition of Nanocrystalline Diamond by HFCVD in Different Materials
Authors: Santos J.A. , Neto V.F. , Ruch D. , Grácio J.
Published: July 2012

Nanocrystalline diamond films, as other forms of diamond, possess a set of extreme properties, such as high thermal conductivity, hardness and resistance to hazard environments. Although an enormous focus has been placed into the deposition of nanocrystalline diamond films, most of this research uses microwave plasma assisted CVD systems. However, the growth conditions used in microwave systems cannot be directly used in hot-filament CVD systems. In this paper, it is meant to enlarge the knowledge of the process of depositing nanocrystalline films on different engineering materials, by means of hot-filament CVD systems. The coated materials include silicon (Si); titanium (Ti); tungsten carbide with cobalt as binder (WC-Co); and tungsten carbide with nickel as binder (WC-Ni). On the former two substrates, the diamond films were achieved on the bare substrates and with the use of an interlayer. The interlayers used were chromium nitride (CrN) and titanium aluminium nitride (TiAlN). Additionally, the as-grown films were characterized for hardness, quality and microstructure using scanning electron microscopy, Raman spectroscopy and nanohardness testing.
Photoluminescence of GdVO4:Eu3+, Al 3+ Phosphors under VUV Excitation
Authors: Park K. , Heo M.H. , Kim Y. , Kim J.Y.
Published: July 2012

The microstructure and photoluminescence properties of Gd0.94-xAlxEu0.06VO4 (0≤x≤0.04) phosphors with various Al3+ contents were investigated. The phosphors showed a nanocrystalline nature and a high-quality powder characteristic. The crystallite sizes of the phosphors were calculated to be 46-48 nm. The annealed Gd0.94-xAlxEu0.06VO4 phosphors crystallized in the tetragonal structure. In the emission spectra, several emission peaks were observed over the measured wavelength range (500-750 nm), which were caused by the difference in the transitions of Eu3+ ions, depending on the local symmetry (5D0 → 7Fj, j = 1, 2, 3, and 4). The strongest emission peak was located at 619 nm, providing a high-purity red emission. The doped Al3+ yielded significantly enhanced the emission intensity. The most intense high-purity red emission was obtained for Gd0.93Al0.01Eu0.06VO4.
Effect of Hydrostatic Pressure on Nano Crystalline Materials Behavior
Authors: Jafari Nedoushan Reza , Farzin Mahmoud
Published: July 2012

One of the Remarkable Differences between Mechanical Behavior of Nano-Crystalline and Coarse-Grained Materials Is Tension Compression Asymmetry that Has Been Experienced in Nano-Crystalline Materials. In this Paper a Constitutive Model Is Proposed which Considers Dominant Operative Deformation Mechanisms of Nano-Crystalline Materials Including Grain Interior Plasticity, Grain Boundary Diffusion and Grain Boundary Sliding. A Grain Size Dependent Taylor Type Polycrystalline Model Is Used to Predict Grain Interior Deformation. Three Dimensional Relationships Are Proposed to Relate Macro Stress and Strain Rate in Grain Boundary Mechanisms. The Effect of Normal Stress Acting on a Boundary Is Also Considered in Grain Boundary Sliding, Therefore, Effect of Hydrostatic Pressure Is Included in the Model. The Proposed Model Is Used to Predict Strength of Nano-Crystalline Copper in both Tension and Compression and Good Results Are Obtained Comparing with Experimental Data. The Model Also Predicts Various Behaviors of Nano-Crystalline Materials Observed in Literature's Experiments and Molecular Dynamic Simulations. Some Examples Are: Inverse Hall-Petch Effect; Tension and Compression Maximum Strength Grain Sizes; Tension Compression Asymmetry and its Change Vs. Grain Size and Strain Rate and the Yield Locus Shape.
Building up Multiwall Carbon Nanotubes Nanostructures inside Millimetric Channels of Ceramic Monoliths
Authors: Pérez-Cadenas M. , Muñoz-Andrés V. , Rodríguez-Ramos I. , Maroto-Valiente A. , Guerrero-Ruíz A.
Published: July 2012

Multiwall carbon nanotubes were grown inside the millimetric channels of commercial ceramic materials, cordierite monoliths, using a modified catalytic chemical vapor deposition method. Fe(CO)5 liquid catalyst precursor was introduced in gas phase at the same time as the acetylene carbon source to allow a more uniform distribution of carbon nanotubes on the substrate surface. Different techniques were used for the characterization of the obtained multiwall carbon nanotubes such as scanning and transmission electron microscopies, N2 adsorption isotherms, Raman spectroscopy and thermogravimetric analysis. The results show that the surface of the ceramic monolith is progressively covered with multiwall carbon nanotubes reaching total coverage for longer times under reaction. The carbon nanotubes were built up with a tree-like morphology. So, firstly larger carbon nanotubes are formed as the tree trunks on the cordierite surface, followed by the growing on them of narrower and longer nanotubes suggesting the tree branches.
Improvement in the Oxidation Resistance of β-SiAlON Ceramics Produced from Mechanically Milled Powders
Authors: Eser Onur , Kurama S.
Published: July 2012

In the present study the oxidation behavior of β-SiAlON ceramics, which were produced from conventional and high energy mechanical milled powders, was investigated. High energy mechanically milled powders have lower particle sizes ( 130 nm) than those of conventional powders (216 nm) and fully densified at lower temperatures with less amount of additives. The amount of additive is an important parameter to improve the high temperature oxidation resistance of SiAlON ceramics. The cyclic and isothermal oxidation tests were carried out at 1300 and 1400°C in dry air environment. The weight gain of oxidized samples was measured during the oxidation process. The alteration of oxide layer was analyzed by XRD and SEM. The results indicate that oxidation resistance of the samples produced from mechanically milled powders with less amount of additive is higher than that of conventional one. Therefore, β-SiAlON ceramics which were sintered at 100°C lower temperatures with less amount of additive (3.5 wt. % Y2O3), showed a better oxidation resistance.
Preparation and Characterization of Poly(vinyl Butyral)-Polyaniline-Montmorillonite Nanocomposites
Authors: Anadão Priscila , Valenzuela-Díaz Francisco Rolando , Wiebeck Hélio
Published: July 2012

Poly(vinyl butyral)-polyaniline-sodium montmorillonite nanocomposites were prepared via polymerization of aniline between clay mineral platelets at two different pH levels (2.0 and 5.0), followed by dispersion of the polyaniline-sodium montmorillonite nanocomposite in a poly(vinyl butyral) solution. A comparison was made of the effect of the pH levels and the polyaniline-sodium montmorillonite nanocomposite precursor on the final structures of the poly(vinyl butyral) nanocomposites and their electrical conductivities. X-ray diffraction patterns revealed the formation of nanocomposites at both pH levels. UV-Vis spectra indicated that the polyaniline formed at both pH levels was conductive, with the UV-Vis spectra presenting a band at 420 nm corresponding to the polaronic form and the beginning of a new band at 600 nm indicating the presence of polaronic segments. FTIR spectra revealed the peaks of the groups present in polyaniline and poly(vinyl butyral) nanocomposites. The electrical conductivities of the polyaniline and poly(vinyl butyral) nanocomposites prepared at pH 2.0 were lower than those of the same nanocomposites prepared at pH 5.0, probably due to the lower formation of polyaniline chains in a more acidic dispersion and to the final configuration of polyaniline in the nanocomposites.
Measurement of the Electrochemical Diffusion Coefficient of Li-Ion in LiFePO4 by Constant Current Step
Authors: Zeng Zhi Feng , Zhang Hai Yan , Liu Min Xia , Xu Yong Zhao
Published: July 2012

The lithium ions transferring into cathode material are similar as nonequilibrium carrier in semiconductor while the cell discharges at constant current small enough. The inpouring Li-ions can be called nonequilibrium Li-ions. The electrochemical diffusion coefficient, named as D, can be worked out approximately in terms of the relationship between the concentration of nonequilibrium Li-ions and the relevant potential difference. The D was found 3.21×10-10cm2/s for LiFePO4doped with 10% acetylene black.
Performance Study on Zirconia Cloth Separator for High Pressure Ni-H2 Battery
Authors: Gao Fang
Published: July 2012

High pressure NiH2 battery is a kind of secondary power consists of a nickel electrode and the hydrogen electrode with the quality of high stability, long service life, overcharge and overdischarge resisting advantages, the United States, Russia and France have launched high pressure NiH2 batteries and has been widely used in satellite, space stations and other areas. Performance of strength, Ability of Antioxidation, Chemical Durability, Dimensional Stability and akali retaition ability were strictly required by NiH2 battery’s seporatosr, zirconia cloth seporator can satisfy the use requirement in many aspects. Physical and chemical properties of areo density, average thickness, alkaline retention ability, alkaline absorbing ratio and battery performance were tested in this paper.
Improvement in the Thermoelectric Properties by Ag/Sb Co-Substitution in PbSe
Authors: Li Jun Qin , Li X.X. , Li S.P. , Wang L. , Liu F.S. , Ao W.Q.
Published: July 2012

The thermoelectric properties of Ag-doped and Ag/Sb codoped PbSe, prepared by furnace melting, quenching, ball milling and spark plasma sintering (SPS) techniques, were investigated. The X-ray diffraction (XRD) analysis indicated that all samples crystallize in the NaCl-type structure without noticeable secondary phase. The substitution of Ag1+ ion for Pb2+ ion in PbSe caused the compound changed from n-type semiconductor to p-type semiconductor. The lower Ag doped sample Pb1-xAgxSe with x = 0.002 remains n-type conduction of PbSe, shows high electrical resistivity and thus low figure of merit (ZT). However, the higher Ag doped samples Pb1-xAgxSe with x = 0.004, 0.006, 0.008 exhibit n-type conduction, low electrical resistivity and thus leads to the higher ZT. The maximum ZT of the alloy Pb0.996Ag0.004Se reaches 0.66 at 673K, much higher than 0.24 of PbSe at the same temperature. A proper Sb doping in the n-type semiconductor Pb0.998Ag0.002Se can remain its n-type semiconductor, modify the carrier concentration, decrease the electrical resistivity and thus enhance the thermoelectric property. The alloy Sb0.002Pb0.998Ag0.002Se shows a ZT value of 0.59 at 573K, much higher than 0.26 of the sample Pb0.998Ag0.002Se at the same temperature.
Thermoelectric Properties of a Wide–Gap Chalcopyrite Compound AgInSe2
Authors: Ying P.Z. , Zhou H. , Gao Y.L. , Li Y.Y. , Li Y.P. , Lian X.L. , Cui J.L.
Published: July 2012

Here we report the thermoelectric properties of a wide–gap chalcopyrite compound AgInSe2, and observed the remarkable improvement in electrical conductivity σ, due to the bandgap (Eg = 1.12 eV) reduction compared to In2Se3. The improvement in σ is directly responsible for the enhancement of thermoelectric figure of merit ZT, though the thermal conductivity is much higher at 500 ~ 724 K. The maximum ZT value is 0.34 at 724 K, increasing by a factor of 4, indicating that this chalcopyrite compound is of a potential thermoelectric candidate if further optimizations of chemical compositions and structure are made.
Preparation of Graphene-Like Carbon Materials as Electrodes of Electric Double Layer Capacitors
Authors: Mi Hong Wei , Liu Jian Hong , Sun Hong Yuan , Wu Shuang Quan , Zhou Han Ping , Cao Hui Qun , Chen Jing Zhong
Published: July 2012

Graphene-like carbon materials (GCMs) are prepared by the carbonization of liquid acrylonitrile oligomer (LANO) at 600-1400 °C for 4 h in an Ar atmosphere. LANO undergoes thermal oxidative dehydrogenation and preliminary cyclization by pre-process in air at low temperature (120 °C) and high temperature (220 °C) before the carbonization. Surface chemistry，crystalline and pore structures of the GCMs are characterized by scanning electron microscope (SEM), power X-ray diffraction (XRD) and N2 adsorption respectively. Comparison of the effect of various carbonization temperatures on the electrochemical performance of the electric double layer capacitors (EDLCs) is specifically investigated. The GCMs carbonized at 1300 °C for 4 h shows a fairly good electrochemical performance. The BET surface area of GCM1300 is 81.58 m2/g and the specific capacitance of the GCM1300 is 22.52 F/g in 1 mol/ L Et4NBF4/PC electrolytes.
Preparation and Luminescence Property of LaMgAl11O19
Authors: Min Xin , Fang Ming Hao , Liu Yan Gai , Huang Zhao Hui
Published: July 2012

Lanthanum magnesium hexaaluminate (LaMgAl11O19, LMA) has attracted much interest as its widely used in solid state lasers, TV phosphors and fluorescent lamps. In this paper, LaMgAl11O19 ceramic was pressureless sintered at 1650 °C for 10 h in air atmosphere using LaMgAl11O19 powders prepared by solid-state reaction at 1500 °C for 4 h. The result indicated that the synthesis temperature of LaMgAl11O19 powders was about 1500 °C. The LMA ceramic sample was dense and had a microstructure of platelet-like gains. The excitation spectrum shows two wide bands with the peaks at about 254 nm and 265 nm by monitoring the strongest 362 nm emission, and the emission spectra is consisted of a broad band emission with their peaks near 362 nm with a half-width about 5 nm exciting with 265 nm wavelength.
Effect of Annealing Treatment on Electrical and Optical Properties of ATO Thin Films by Pulsed Laser Deposition
Authors: Chen Fei , Li Na , Shen Qiang , Wang Chuan Bin , Zhang Lian Meng
Published: July 2012

Transparent conducting antimony doped tin oxide (ATO) films have been prepared on quartz glass substrate by pulsed laser deposition (PLD) method which is distinctive to maintain the elemental components between the targets and the obtained thin ﬁlms under optimal conditions. The effect of annealing temperature on the electrical and optical properties of the ATO thin films has been discussed. The annealing treatments have been often employed to reduce the defects and enlarge the grain size for more desirable crystalline structure. As the annealing temperature increases, the ATO thin films exhibited a slightly enhanced crystallinity. Furthermore, annealing treatment can promote both conductivity and transmittance significantly, especially for conductivity. The X-ray photoelectron spectroscopy is used to explore the variation of Sb5+/Sb3+ ratio against the annealing temperature. The optimal resistivity is 2.7×10-3 Ω cm and the average transmittance is about 92% at annealing temperature of 550 oC.
‘Window’ Effect in the Analysis of Universal Dynamic Response
Authors: Gong Xiao Yang , Gu Zhi Feng , Li Tong Wei
Published: July 2012

Studies of ion motion in crystalline and glassy materials, Jonscher power law, which was frequently referred to as the so-called universal dynamic response (UDR) is an effective method, but the power law exponents obtained from curve-fitting are sensitively affected by the frequency window employed in the analysis. So how to choose frequency window and which window can truly describe the nature of the materials, are important for every researcher. In this paper, through analyzing the experimental data of frequency dependence of ac conductivity in 50Li2O–50P2O5 glasses, a simple method to choose frequency window was found and further discussions indicated our choice was reasonable.
Mechanical Properties of La2O3-Al2O3 Ceramics Prepared by Microwave Sintering
Authors: Ai Yun Long , He Fei , Liang Bing Liang , He Wen , Chen Wei Hua
Published: July 2012

The influence of La2O3 on the phase and microstructure evaluation and mechanical properties of La2O3-Al2O3 ceramics sintered with 2.45 GHz microwave energy was investigated. The results showed that La2O3 could densify the pure alumina with a lower sintering temperature and a short sintering time. La2O3 reacted with Al2O3 to form LaAl11O18 completely and the amount of LaAl11O18 increased with the increasing content of La2O3, distributing at the Al2O3 grain boundaries. The specimen doped with 10 vol.% and 15 vol.% La2O3 sintered at 1500 °C exhibited plenty of columnar grains with draw ratio about 1:4. The existence of columnar grains enhanced the microhardness and fracture toughness of La2O3-Al2O3 ceramics.
Effect of Interfacial Treatment Process on the Microstructure and Properties of Cf/SiC Ceramic Matrix Composites
Authors: Li Xiu Qian , Qiu Hai Peng , Jiao Jian , Luo Jing Hua , Wang Yu
Published: July 2012

Abstract. This paper investigated the Cf/SiC ceramic matrix composites. By utilizing different interfacial treatment processes to prepare carbon-fiber preform, the preform was then densified by infiltration and pyrolysis(PIP) with polycarbosilan/xylene solution as precursor, and the Cf/SiC ceramic matrix composite specimens were fabricated. Mechanical tests such as bending test and fracture toughness were performed for Cf/SiC samples. The results show that the interfacial bonding strength in the sample with high-temperature treatment process was improved due to removing surface sizing. The samples which were treated up to 1400°C exhibited the highest three-point flexural strength, up to 595MPa; The samples which were treated up to 1400°C and deposited by pyrolytic carbon(PyC) coating shows the highest fracture toughness value which was 20.70MPa•m1/2.
Preparation and Characterization of Functional Gradient Porous ZrO2 Ceramics
Authors: Wang Xiao Bei , Lin Yuan Hua , Deng Xu Liang
Published: July 2012

Porous zirconium dioxide (ZrO2) ceramics has been widely used in biomedicine, heat-insulation and piezoelectric actuators. In this study, a kind of porous ZrO2 ceramics with the gradient porosity and pore sizes was designed to be a composite lamellar material. The porosity and pore size change regularly through the thickness of the layers. This porous lamellar zirconic material has been prepared by the solid state reaction consisting of yttria-stabilized zirconia (YSZ) and stearic acid (SA) powders. The porosity and pore size can be tuned by the addition of SA. The mechanical properties of the graded porous ZrO2 have been studied in detail. The results show that the mechanical characteristics of the gradient porous ZrO2 can be controlled by changing the porosity and pore size.
Preparation of Zirconia Fiber Body with Extrusion-Extraction Molding
Authors: He S.A. , Zhu Xiao Yan
Published: July 2012

Zirconia fiber body was prepared with Extrude-extracting, using zirconium slurry made of partial stabilized Zirconia ultra-fine powder. The result shows that，acetone is the first choice as extraction agent because of its notable effect of water extraction on zirconium slurry. The Zirconia fiber body, which length is over 2 centimeters and solid content is more than 98% ( weight percent ), can be prepared while the range of solid fraction in slurry is in 36 vol％～49vol％, with addition less than 1% ammonium polyacrylic acid, the extrusion force is range in 1641.5 Pa～6566.2 Pa. The solidfication mechanism transformation from slurry streamlet to fiber body is particle caking, result in water being extracted by aceton and static repulsion force falling as powder surface electronmotive force being reduced, when zirconium slurry extruded into solvent with low dielectric constant. Difference of velocity distribution of slurry passing through spinneret orifice and very small surface tension between slurry and extraction agent cause coarseness occurred on the fiber body surface.
Fabrication of Micro-Nano Structured Super-Hydrophobic Surface and Drag Reduction in Channels
Authors: Fu Cheng Song , Cao Dang Chao , Zhang Zhen , Lu Si , Yao Zhao Hui
Published: July 2012

In order to research the characteristic of flow drag reduction on large area super-hydrophobic surface, we have been designed a new processing technology to construct a micro-nano structure super-hydrophobic surfaces which formed by surface nanometer fly ash cenosphere. The experimental result of the flow drag reduction tested on macro-scale channel in laminar flow is very well, and the maximum drag reduction is 25.6%.
Examination of Initial Melting Temperature and Microstructure of Vita Alpha Veneering Porcelain
Authors: Zhang Bin , Hua Ze Quan , Chen Ji Hua , Sun Lian Jun , Liu Shan
Published: July 2012

Through this experiment, we try to determine the initial melting temperature of Vita Alpha porcelain powder and observe micro-structural changes of it. To determine softening temperature point, the powder of Vita Alpha has been sintered at 600°C, 700°C, 800°C and 900°C after mixed with sintering water. It was evaluated through direct observation in combination with scanning electron microscopy (SEM) and differential thermal analysis (DTA). Results shows that with sintering temperature increased, Vita Alpha veneering porcelain was enhanced gradually and the sintering degree was also improved. Sintering at 600°C, the powder was still in original state. But at 700°C the grain size and translucency were both increasing and grain boundaries cannot be clearly distinguished, which means the initial integration. When sintering temperature is at 900°C, Vita Alpha porcelain has been a translucent uniform material. In terms of DTA result, there are no significant endothermic and exothermic peaks in the softening, melting and crystallizing process of Vita Alpha powder. It indicates no significant thermal effect can be found, which infers that Vita Alpha porcelain powder contains a large number of ceramic components, rather than mainly of glass composition. Therefore, the conclusion is initial melting temperature of Vita Alpha porcelain powder is higher than 600°C, less than 700°C. With sintering temperature increased, Vita Alpha porcelain was gradually enhanced. There is no significant thermal effect in the softening, melting and crystallizing process, which indicates that Vita Alpha powder contains a large number of ceramic components, rather than mainly of glass composition.
Microstructure Modification of NiO/YSZ Anode in Solid Oxide Fuel Cell by Particle Size Gradation of YSZ
Authors: Chang Qi Bing , Wang Xia , Zhou Jian Er , Wang Yong Qing , Meng Guang Yao , Liu Xing Qin
Published: July 2012

The idealized microstructure of NiO/YSZ anode of solid oxide fuel cell (SOFC) is that YSZ structures the bone of the anode and NiO is segregated by YSZ to keep Ni from congregation. To obtain this microstructure, the mixture of coarse YSZ and fine YSZ was used. The effect of the particle size gradation of YSZ on the microstructure of anode was studied. The results show that the homogenous microstructure can be obtained when the mass ratio of the coarse YSZ (d50＝3.38µm) to the fine YSZ (d50＝0.4µm) is 7:3. The pre-sintering temperature has obvious effect on the porosity of the NiO/YSZ. The bending strength of NiO/YSZ and Ni/YSZ are 123MPa and 85MPa, respectively. The reduction of NiO to Ni has less effect on the bending strength for 40vol%Ni/YSZ (7/3).