bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Elevated Temperature on the Mechanical Behavior of Natural Aggregate Concrete
Authors: Yan H.Q. , Wang Qingyuan
Published: November 2010

Reinforced concrete construction is very common these days and extensively used both in industrial and commercial buildings. With the gradual rise in occurrences of fire accidents in recent years, a more thorough and quantitative understanding of the damage phenomenon in natural aggregate concrete structures is required. However, little research has been done to study natural aggregate concrete behavior under high temperatures. The mechanical behavior of concrete could actually be more complex under high temperature conditions than at room temperature, for instance. Restoration and reinforcement of the structures exposed to fire may have to be based on residual strength analysis and therefore require a correlation between temperature and mechanical properties. Thus, in order to meet the modern challenges of rapid engineering advances and societal development, further research on the concrete material and its structural behavior at high temperatures becomes extremely important.
The present paper deals with investigations on the effect of high temperature exposure on the compressive strength of natural aggregate concrete. Experiments were conducted to study the compressive strength variations with increasing temperatures, up to 700 °C, and the subsequent cooling modes such as natural and spray cooling. Results show that the compressive strength gradually decreases with increasing temperatures.
A Method of Fatigue Damage Analysis for Sandwich Panels on Ship
Authors: Xue Qi Chao , Zou Guang Ping
Published: November 2010

A method of fatigue damage analysis for sandwich panels on ship is studied in this paper. When ship is navigating on the sea, the waves that ship encounters can be regarded as a stochastic process. And responses of ship movement can also be regarded as a series of stochastic spectrums. By using of finite element method, loads spectrums of inner ship structures in different sea conditions can be obtained. Then short term or long term distribution of stress range can be determined. Residual stiffness modal is used to describe the damage of sandwich panels under fatigue loads. And fatigue damage variable D is defined based on stiffness degration. An integral equation to calculate fatigue damage under loads spectrum is constructed to describe the damage of ship sandwich structure in long term and short term stress spectrum distributions.
Structure Buckling Load Interval Analysis of Ventilated Supercavitating Vehicles
Authors: Chen Wei Dong , Zhou Ling , An Wei Guang
Published: November 2010

Axial and circumferential critical buckling loads of thin cylindrical shell with stiffened rings are obtained by semi-analytical FEM. Then the interval widths of critical buckling loads which are obtained by interval analysis method are compared to those obtained by convex model method. The lower and upper bounds of axial and circumferential critical buckling loads increase with the increase of number of ring and are larger when the ring is placed on the inside of the shell than that is placed on the outside of the shell. The influence of variety of interval width of each basic variable on the variety of interval widths of critical buckling loads is obtained in this paper.
Mechanical Properties of Shape Memory Alloy Reinforced Composite
Authors: Wang Zhen Qing , Zhou Bo , Guo Xiao Gang , Zhou Li Min
Published: November 2010

Shape memory alloy (SMA) has various application fields due to its shape memory effect and super elasticity. It can also be embedded into other material to produce SMA reinforced composite (SMAC). SMAC is a good candidate to realize structural smart control. In this paper the mechanical properties of SMAC in the plane stress state is investigated based on the theory of mechanics of composite material and the constitutive model expressing the thermo-mechanical behaviors of SMA.
Fatigue and Acoustic Emission Behavior of Plasma Sprayed HAp Top Coat and HAp/Ti Bond Coat with HAp Top Coat on Commercially Pure Titanium
Authors: Loanapakul Teerawat , Otsuka Yuichi , Mutoh Yoshiharu
Published: November 2010

In the conventional hydroxyapatite (HAp) coating, the surface of commercially pure titanium (Cp-Ti) is blasted with Al2O3 grid-blasting powders and then plasma-sprayed with HAp. To improve the adhesive strength of HAp coating, the grid-blasting with Al2O3 powders and subsequently wet-blasting by HAp/Ti mixed powders were applied on Cp-Ti substrate at ambient temperature. On the wet-blasted surface of Cp-Ti, two-layers of coating composed of HAp/Ti bond coat and HAp top coat were deposited by plasma spraying. Both types of HAp-coated specimen could survive up to 107 cycles without spallation of HAp coating at the stress amplitude of 120 MPa under four point bending fatigue test. In order to clarify mechanical failure behavior of the coatings and Ti substrate, acoustic emission (AE) signals during the entire fatigue process were observed. Relationship between AE behavior and cracking process of coated specimen was evaluated. HAp top coat with HAp/Ti bond coat strongly improved the adhesive and cohesive strength, where dense AE signals occurred at the early stage of fatigue test corresponded to plastic deformation of Ti substrate and micro-cracks in coated layers. AE signals occurred at the final stage corresponded to crack propagation in coated specimen and spallations of coated layers.
Mechanism and Experimental Verification of Degradation of RC Beams Induced by Concrete/Rebar Bonding Failure
Authors: He Xiao Bing , Huang F. , Zhang C.Y.
Published: November 2010

From the perspective of Fracture Mechanics, concrete/rebar bonding failure process in reinforced concrete (RC) structures means the decreasing of the crack closure force imposed by rebar in RC beams, which will result in crack propagation, and eventually structural damage. In this paper the crack-arresting mechanism of the concrete/rebar bonding stress in RC beams was analyzed, which was employed to reveal the degradation mechanism of RC beams induced by concrete/rebar bonding failure; and bending tests of RC beams were presented where effects of concrete/rebar bonding failure on bending performance of RC beams had been investigated. The concrete/rebar bonding failure was obtained by wrapping the rebar with different length of plastic film during casting. The results shows effective concrete/rebar bonding is the key to provide crack closure force, which can prevent functional degradation of RC beams.
Fracture Process Zones in Polygranular Graphite in Bending
Authors: Nakhodchi S. , Hodgkins Andrew , Moskovic Robert , Smith David John , Flewitt Peter E.J.
Published: November 2010

The formation of fracture process zones in polygranular reactor core moderator graphites subjected to four-point bending has been investigated. The three-dimensional digital image correlation technique has been combined with resistance strain gauge measurements to evaluate, both the localised and the global displacements during testing. The non-linear load-displacement characteristics prior to peak load are correlated with the localised displacements which can extend up to ~3mm (process zone) from the tensile surface of the specimen. At peak load a macro-crack propagates rapidly along an irregular path controlled by the direction of the applied tensile load and the microstructure of the graphite. These cracks arrest prior to complete separation of the specimen. Localised tensile process zones extend for distances of up to ~3mm ahead of the tips of these cracks.
From Wipers to the JKR Equation: Boundary Lubrication and Adhesion of Rubber
Authors: Roberts Alan D.
Published: November 2010

This review describes early work on rubber wiper blades and subsequent investigations. Observations on model wipers pressed against glass showed that the dry contact width was greater than that predicted by the classical Hertz equation, due to adhesion. That led to the establishment of the JKR equation to account for the adhesion. Although originally intended for ‘soft’ contacts, the equation now finds wide use. Surprisingly, the boundary lubrication aspects of the work revealed the action of repulsive forces that could be directly measured between rubber and glass in the presence of water. The quality of lubrication is subject to the acidity/alkalinity of the water.
Contact Problems at Nano/Microscale and Depth Sensing Indentation Techniques
Authors: Borodich Feodor M.
Published: November 2010

An overview of development of indentation techniques and connections between contact mechanics and methods of extracting mechanical characteristics from indentation data is given. Observed disagreements between the experimental observations and the models of indentation are discussed. It is shown that this disagreement is often caused by violation of hypotheses that are used in the formulation of the appropriate boundary-value contact problems and strictly speaking one cannot apply directly the solutions of Hertz type contact problems to indentation tests employing the sharp indenters. It is shown that commonly used experimental test involving sharp pyramidal and conical indenters may be applied to study plastic properties of materials while this approach is not very accurate for estimations of elastic modulus of the test solid. The recently proposed by Borodich and Galanov non-direct method that employs data of elastically loading of a spherical indenter is described. It is argued that the non-direct method can be used for determination of both the work of adhesion and elastic modulus of the tested material.
Self-Sustained Fracture Waves in Soda-Lime Glass
Authors: Chaudhri M. Munawar
Published: November 2010

High-speed framing photography in conjunction with circularly polarised light has been employed to monitor qualitatively the state of residual stress in Prince Rupert’s drops of soda-lime glass undergoing disintegration by a self-sustained fracture wave in the glass drops. It is revealed that the fracture wave through a Prince Rupert’s drop is driven by the residual stress in the drop, with the propagation speed of the fracture wave being (1700 ± 100) ms-1, which is close to the terminal speed of individual cracks in the soda-lime glass, but is much smaller than the longitudinal wave speed of 5300 ms-1 in the glass. These observations support our recently reported observations and also give support to our conclusions that the fracture wave speed of a self-sustained fracture wave is equal to the terminal speed of individual cracks in the glass. Some preliminary observations from fracture waves in Prince Rupert’s drops of a lead oxide glass are also described, which show that in Prince Rupert’s drops of the lead oxide glass the fracture wave is also self-sustained and it travels through the drop at a steady and stable speed of (1300 ± 100) ms-1, which is also considerably smaller than the longitudinal wave speed of 4800 ms-1 in the lead glass. A brief comment is also made on the fracture waves observed by other workers in brittle oxide glasses and solids generated by plate impacts and shock waves.
Structural Transition and Magnetic Properties of (Sr2-3xLa2xBax)FeMoO6
Authors: Xu Zhen Feng , Liang Jun , Pei Juan , Yin Yan Yan , Li Chang
Published: November 2010

Ordered double perovskite oxides (Sr2-3xLa2xBax)FeMoO6 (0≤x≤0.3) have been investigated in this work. X-ray powder diffraction reveals that the crystal structure of the compounds changes from a tetragonal I4/m lattice to a cubic Fm 3m lattice around x=0.2. Though the nominal average size of the A site cation of (Sr2-3xLa2xBax)FeMoO6 is designed to be almost independent of x, the refinements of the crystal structure show that the lattice constants increase with x in both the tetragonal and the cubic phase regions due to electron doping. As the x increases, the degree of cationic ordering on the B site is decreased pronouncedly, while the Curie temperature of the compounds is nearly unchanged.
Preparation and Characterization of Spin-Coated Tetra-(tert-butyl) Phthalocyanine Copper Films
Authors: Wang Bin , Wu Yi Qun , Chen Zhi Min , He Chun Ying , Duan Wu Biao
Published: November 2010

Spin-coated films of tetra-(tert-butyl) phthalocyanine copper (CuPc(t-Bu)4) complex were obtained and characterized by Uv-vis absorption spectra and atomic force microscopy. A good linear relationship of the absorbance and solution concentration was detected. Low concentration solution could afford smooth, homogeneous and porous macrostructure film surfaces as indicated by atomic force microscopy. The responses of the film to NH3 were investigated at room temperature. In addition, the response and recovery characteristics, selectivity, stability and effect of thickness of the film to NH3 were also studied. The results indicated that the CuPc(t-Bu)4 spin-coated film could be exploited as an NH3 sensor at room temperature.
Sinterability and Microwave Dielectric Properties of Li2CO3-V2O5 Added Mg4Nb2O9-CaTiO3 Composite Ceramics
Authors: Pei Cui Jin , Yao Guo Guang , Ma Hong , Tian Xiu Lao
Published: November 2010

The effects of Li2CO3-V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of Mg4Nb2O9-CaTiO3 composite ceramics have been investigated. The phase compositions and microstructure were analyzed using X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy techniques. The densification sintering temperature is lowed from 1275oC to 1200oC with an amount LV addition. For the specimen with 1.5 wt% LV addition sintered at 1200oC for 5 h exhibited dielectric properties: εr=23, Q·f=24 000 GHz (at 7.7GHz ), τf =1.0 ppm/oC. These properties were correlated with the formation of non-stoichiometric compound Mg4(Nb1-xTix)2O9-δ.
Synthesis and Light-Emitting Properties of Solution-Processable Oligothiophenes Containing Triazole Moiety
Authors: Kim Bo Eun , Lee Sung Koo , Lee Kyeong K. , Lim Eun Hee
Published: November 2010

The aromatic triazole is an interesting electron-injection/transport chromophore because it possesses high electron affinity and thermal stability. In organic lighting-emitting diodes (OLEDs), highly electron-deficient triazole (Tz) derivates have been demonstrated to have more efficient electron-transport and hole-blocking characteristics and have a higher stability to high current density than the oxadiazole derivates. In this study, we have successfully synthesized a star-shaped soluble oligomer,4-(4-butylphenyl)-3,5-bis(4-(5'-hexyl-2,2'-bithiophen-5-yl)phenyl)-4H-1,2,4-triazole(Tz-2T-Hex) via Suzuki coupling reaction. The Tz-2T-Hex shows a red-shifted UV-vis absorption spectrum than Tz-Br with a maximum at 380 nm, due to the introduction of two bithiophene units at both ends. As film, Tz-2T-Hex showed the PL maximum at 530 nm. Tz-2T-Hex emitted light of a white color with the CIE coordinates (0.32 and 0.34).
Response Sensitivity of Faraday Magneto-Optical Effects of Ferrofluid
Authors: Wang Shi Bin , Yu Cheng Bo , Du Lin , Sun Cai Xin , Yang Jia
Published: November 2010

The transmitted intensity and the modulation depth of plane polarized light are implemented to investigate influences of the low frequency external magnetic field on the ferrofluid film. The frequency of AC magnetic field is modulated from 5Hz to 400Hz, and the thickness of ferrofluid films are changed as 12 μm, 25 μm, 140 μm and 520 μm, and the mass concentration of magnetic nanoparticles is 5 %, 10 %, 20 % and 33.6 %, respectively. The experimental results show that (1) the mean value of the optical transmittance of ferrofluid film is decided by the thickness of ferrofluid film and the mass concentration of nanoparticles, but the frequency of magnetic field has no direct relation with it; (2) under a given magnetic field intensity, the optical modulation depth of ferrofluid film is determined by the film thickness, the nanoparticle concentration and the magnetic field frequency. It is further found that the single relaxation characteristics of magnetic nanoparticle, whose size is smaller than the critical value of the single magnetic domain, is the important factor of the frequency properties of nanoparticle in ferrofluid. These results may be beneficial to applications of ferrofluid in magneto-optic sensors.
Prepared and Microwave-Absorption Properties of BN Coated Ni Nanocapsules
Authors: Shi Gui Mei , Lian Shu , Song Ge , Zhang Jin Bing
Published: November 2010

BN coated Ni nanocapsules were prepared by arc evaporating Ni-B amorphous alloy powders synthesized by a mechanochemical reaction, and their microstructure, surface component as well as electromagnetic properties (2-18 GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray diffraction , photoluminescence spectra (PL) and a network analyzer, respectively. The reflection loss R (dB) of the nanocapsules less than -20 dB was obtained in the frequency range of 4.3-18 GHz for an absorber thickness of 1.4-6 mm. An optimal reflection loss of -32.0 dB was reached at 13 GHz with an absorber thickness of 2 mm. The microwave absorptive mechanisms of BN-coated Ni nanocapsule absorbent were discussed.
Preparation and Properties of Cationic Starch with High Degree of Substitution
Authors: Liu Quan Xiao , Li Jin Li , Xu Wen Cai
Published: November 2010

Using sodium hydroxide as its alkali catalyzer, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride as its quaternary agents, cationic starch with high degree of substitution was made by semi-dry process. The prepared cationic starch contains quaternary ammonium groups by the infrared spectrum analysis. From the scan electron microscope pictures of starch and cationic starch, cationic starch can be clearly seen to have substituted the quaternary ammonium salt groups and the structure of mutual penetration of flexible quaternary ammonium salt groups and rigid starch has formed. The tensile strength of paper improved by cationic starch with high degree of substitution is far more than that by cationic starch with low degree of substitution and poly diallyl dimethyl ammonium chloride. The scan electron microscope pictures of the surface and fracture of the paper show that the distribution of the paper fiber which added additives are apparently tight and uniform and there are many small fibers obtained on the surface of paper samples. The fibers of the paper sample which added additives have more fracture themselves and have less extraction entirely. It indicates that the force between fibers has been strengthened by cationic starch additive.
Vapor-Induced Response of HTPB/MWNTs-COOH PU Conductive Films Based on Hydrogen Bonding Interactions
Authors: Luo Yan Ling , Niu Li , Xu Feng , Yao Yong
Published: November 2010

Novel polyurethane (PU) conducting films consisting of hydroxyl-terminated polybutadienes (HTPB) and carboxyl functionalized multi-walled carbon nanotubes (MWNTs-COOH) were developed by a simple coupling approach based on hydrogen bonding interactions between MWNTs-COOH and PU moieties. The morphologies and structural characterization were conducted by means of FTIR, TEM and TGA etc; and the influence of the MWNTs-COOH loading and curing temperature on vapor response was investigated. The experimental results indicated that a micro-phase separation structure between soft and hard segments was formed, and MWNTs-COOH was tightly encapsulated by PU moieties and homogeneously dispersed in the PUs. The developed films displayed selective response to non-polar organic solvent vapor and good long-term stability.
The Effect of Spin-Orbit Splitting on the Third-Order Nonlinear Optical Susceptibility in CdSe/ZnS Quantum Dot Materials
Authors: Yu Chun Jing , Guo Xiao Zhen , Yao Duan Zheng
Published: November 2010

The nonlinear optical susceptibility with inter-subband transitions between conduction band and valence band is theoretically calculated for CdSe/ZnS core-shell quantum dot (QD). Under the effective-mass approximation, the eigenenergy and wavefunction of electrons and holes have been calculated by solving stationary Schrödinger equation. The third-order nonlinear optical susceptibilities χ(3) of quadratic electro-optic effects (QEOE) have been also calculated in the case that spin-orbit splitting is considered.
Effect of Sputtering Pressure on the Formation of Semiconducting Mg2Si Films
Authors: Xiao Qing Quan , Xie Quan , Zhao Ke Jie , Yu Zhi Qiang
Published: November 2010

Semiconducting Mg2Si films were fabricated on Si (111) substrates by magnetron sputtering and subsequent annealing, and the effects of sputtering pressure on the Mg2Si film growth were studied. The structural and morphological properties of Mg2Si films were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the Mg2Si (220) main diffraction peak intensity increased and then decreased with the increasing of sputtering pressure. The (220) diffraction peak got its maximum at 3.0 Pa sputtering pressure. The intensity of Mg2Si (200) and (400) diffraction peaks increased rapidly as the sputtering pressure decreased when the pressure was lower than 1.5 Pa. The films prepared at higher sputtering pressure had very irregular microstructures, and the surface of semiconducting Mg2Si films became smoother with the decreasing of the sputtering pressure.
Photocatalytic Performance of Polyoxometallate Intercalated Layered Double Hydroxide
Authors: Zhang Yu Hui , Su Ji Xin , Wang Xiao Peng , Pan Qi , Qu Wen
Published: November 2010

Based on X-ray diffraction results, the gallery height of modified Mg3Al-LDH was expanded to 9.6Å from the original 4.8Å, indicating that the H3PW12O40 was indeed inserted into the hydroxide layers. Moreover, the results of FT-IR spectra proved the Keggin structure of PW11O397- species. The resulting material showed a high activity of degradation of methyl orange in the presence of H2O2 and UV light irradiation.
Characteristics of a Triode Field Emission Display Panel with the Suspension Gate Structure
Authors: Li Yu Kui , Liu Yun Peng
Published: November 2010

With the effective screen-printing technique and high-temperature sintering process, the suspersion gate structure was developed. The silver slurry was printed on the gate substrate to form the gate electrode. Using carbon nanotube as cold field emitter, the triode field emission display (FED) panel was fabricated, and the detailed manufacture process was also presented. The anode back plane, the cathode back plane and spacer combined to device room, in which the suspension gate structure would be included. The distance between the gate electrode and carbon nanotube cathode could be reduced, which could decrease the device manufacture cost because of the small gate voltage. The modulation of emitted electron by the gate voltage would be confirmed, and the field emission characteristics was measured. The sealed FED panel with simple fabrication process and designed structure possessed better field emission uniformity, high display brightness and field emission perofrmance.
Study of Vacuum-Sealed Field Emission Display Device with Discrete Anode Sub-Pixel Layer
Authors: Wu Chao , Zhang Yan Feng , Guo Ting Yue
Published: November 2010

Using carbon nanotube as field emitter, the diode-structure field emission display device was fabricated with conventional sintering techniques. With the precise photolithography process, the indium tin oxide film coated on the anode faceplate surface was etched to form the bar anode electrode. Using the screen-priinting technology, the insulation slurry was prepared on the bar anode electrode surface to form the anode separate layer. So the discrete anode sub-pixels layer structure was developed. For the vacuum-selaed FED device, the typical field emission characteristics were measured and the displayed dot matrix image was also presented. The fabricated FED device with discrete anode sub-pixel layer possessed higher dispaly image brightness, good image disnlay performance and better field emission characteristics.
Bright Photoluminescence of CdTe Quantum Dots Formed in Phosponic-Oleic Acids Binary Surfactants
Authors: Rahmi Aidhia , Umar Akrajas Ali , Salleh Muhamad Mat , Majlis Burhanuddin Yeop , Oyama Munetaka
Published: November 2010

This paper reports the preparation of exceptionally high brightness CdTe quantum dots (QDs) that gives emission in the range of green to red by simply prepared them in a binary mixture of octadecyl phosphonic acid (ODPA) and oleic acid (OA) surfactants. By easy controlling the ratio between the two surfactants in the reaction, the QDs with unique emission, high -brightness and -quantum yield (QY), ca. 63, 87 and 89% for green, yellow and red QDs respectively, can be obtained. Owing to their unique PL and high QY, the CdTe QDs should find an extensive uses in the currently existing applications.
Poly(Acrylic Acid)-Ferric Hydroxide Photosensitive Self-Assembly Film
Authors: Li Xue Feng , Peng Shao Xian
Published: November 2010

A stable and high lubricant ultrathin film was fabricated by self-assembled procedure at room temperature. Thickness of the films was regularly increased with the layer-by-layer self-assembly process in which poly (acrylic acid)-ferric hydroxide (PAA-Fe(OH)3) sol as anion polyelectrolyte and photosensitive diazoresin (DR) as cationic polyelectrolyte. And the process which based on electrostatic attraction was verified by UV-vis measurement. Furthermore, the ionic bonds in the films converted to covalent bonds under UV irradiation. Finally, the surface morphology and microtribology of the films were investigated by atomic force microscopy (AFM) and friction force microscopy (FFM). The results indicate that the films are flat and uniform through the self-assembly technique and the surface friction coefficients maintain at a rather low value.
Optical Properties of Hydrogen Sensitive Films for Surface Plasmon Resonance Optic-Fiber Micro-Sensor
Authors: Li Ze Lun , Tang Yi Ke , Zhou Chuan De , Xu Jing
Published: November 2010

Tungsten oxide (WO3) film material is applied extensively because of its electrochromic property, gasochromic property, photochromic property, electrochemistry, etc. Based on the preliminary study on the preparation and hydrogen sensing properties of platinum-doped WO3 films, we studied the optical properties of hydrogen sensitive WO3 films for surface plasmon resonance (SPR) optic-fiber micro-sensor. In this work, firstly, the structure of SPR optic-fiber hydrogen micro-sensor was discussed. Secondly, we studied the transmissivity of the platinum-doped WO3 films. Thirdly, the reflection index of the films in different environments was discussed. This work can provide theory support for the design of SPR optic-fiber micro-sensor.
Blue Photoluminescence of Sol-Gel Derived SnO2:Sb Films
Authors: Chen Lan Li , Zhai Bao Gai , Huang Yuan Ming
Published: November 2010

By varying the antimony dopant level in the sol-gel solutions, we prepared a series of antimony-doped SnO2 films on slide glass with the sol-gel technique. The transmission, absorption, photoexcitation and photoemission spectra were measured for the sol-gel derived antimony-doped SnO2 films. Under the 300 nm excitation, near untraviolet emission at 390nm and blue emission at 460 nm were recorded from thermally annealed antimony-doped SnO2 films. The effect of the ionic dopant on the photoluminescent properties of the antimony-doped SnO2 films are discussed.
In Situ Preparation of TiO2 Composite Layer upon Ti Alloy Substrate Using Micro-Arc Oxidation and its Photocatalytic Property
Authors: Wang Yong Qian , Jiang Xu Dong , Pan Chun Xu
Published: November 2010

In this paper, a micro-arc oxidation (MAO) approach is introduced for “in-situ” preparing TiO2 composite layer upon the surface of titanium alloy (Ti-6Al-4V) substrate. The surface morphologies, chemical compositions, crystal microstructure and photocatalytic properties of the layers were investigated by using a field emission scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electro-chemical workstation and UV-Vis spectrophotometer. The experimental results revealed that photocatalytic performance of the TiO2 composite layers was much higher than that of the pure TiO2 layer and also exhibited absorption under the visible light irradiation.
Effect of Various CF4/CH4 Flow Ratios on Structure and Optical Band Gap of Fluorinated Diamond-Like Carbon Thin Films
Authors: Xiao Jian Rong , Tong Tao , Li Yan Wei , Li Xin Hai
Published: November 2010

Fluorinated diamond-like carbon (F-DLC) thin films are deposited using radio frequency plasma enhanced chemical vapor deposition under various gas flow ratios. The surface morphology of the F-DLC thin films deposited at lower gas flow ratios is a compact and uniform structure, and it became rough with the increase of gas flow ratios. The relative atomic contents of fluorine and chemical bonding configurations of C-Fx (x=1, 2, 3) in the thin films increases with the increase of gas flow ratios. The optical band gap of the thin films presents a decrease of different degree with the increase of gas flow ratios.
Thin Metal Films and Multi-Layers Structure as Absorbers for Infrared Detectors
Authors: Liu Huan , Song Liang , Zhou Shun , Cai Chang Long
Published: November 2010

As thin metal films are known to act as wide-band absorbers for infrared radiation, in this paper Ni metal films are prepared on the Ge surface of double-sided polishing, The results showed the absorbing properties of the metal layer are strongly influenced by the dielectric function of the sensor material. This paper also describes one multi-layers structure as absorber. The structure included a reflector layer of 100-nm-thick Ti (e-beam evaporation), 2-µm-thick polyimide(spin-coating), and 14.9-nm-thick Ni film (e-beam evaporation). These contain a half transmissive thin metal film, a total reflective thin metal film and a quarter-wave polyimide film. The results showed that, measured performance matches well with theoretical predictions.
Optical, Dielectric and X-Ray Absorption Properties of Soda-Based Glass Fabricated from Thai Quartz Sands Doped with Iron Oxide
Authors: Pongkrapan Sorapong , Yamban S. , Won-In Krit , Dararutana Pisutti , Sirikulrat N.
Published: November 2010

Soda-based glass samples were fabricated in a laboratory scale using quartz sands that was a by-product of feldspar floatation in Tak Province, northern Thailand, and 25-wt% commercial-grade Na2CO3 as the main compositions. Fe2O3 of 0.1 to 10.0 wt% concentrations was doped into the glass mixture. Well-mixed and dried powders were melted in a ceramic crucible for 6 h at 1250°C using an electric furnace. Transparent and bubble-free glass samples were obtained as results. It was found that Fe2O3 dopant turned the otherwise colorless glass to dark brown. Dielectric property and physical properties, such as, color, specific gravity, and refractive index of the glass samples were studied. The samples’ dielectric constant, specific gravity, and refractive index increased with increasing Fe2O3 doping concentration. UV-VIS-NIR and synchrotron-based X-ray absorption spectra were measured and discussed.
Fabrication and Optical Properties of Monodisperse Fine Zinc Oxide Nanorods
Authors: Li Chun Ping , Zhang Jian , Yu Hua Min , Guo Xiu Juan
Published: November 2010

Highly monodisperse ZnO nanorods were synthesized by simple solution chemical process. The produced ZnO nanorods have uniform diameters about 30 nm with average aspect ratios more than 40. Raman and photoluminescence measurements were used to examine their optical properties. Raman spectrum presents weak quantum confinement effects of the fine nanorods. Laser power-dependent photoluminescence spectra show the products have intense UV emissions with narrow full width at the half maximum (FWHM). All the performed experiments determine the good crystal and optical quality of synthesized nanorods.
Properties of Different Nano-Metallic Particles in Optical Trapping
Authors: Zhang Yu Heng , Fang Yin An , Yao Duan Zheng
Published: November 2010

Metal nanoparticles are well-known to exhibit a strong interaction with light, which have very important applications and one of them, recent years, is optical trapping of the metallic nanoparticles. Based on the principle of the optical trapping for metallic nanoparticles, in this paper, the gradient forces and the scattering forces in the optical trapping for gold-, silver- and copper-nanoparticles have been analyzed and calculated numerically. Typical power spectra for gold-, silver- and copper-nanoparticles have been obtained. It is shown from the calculation results that under what condition these metallic nanoparticles can be trapped, and the stability of the potential well for these metallic nanoparticles has been analyzed in order to know whether the well was deep enough for overcoming the gravity and Brownian motion.
The Influence of Dy3+ in the Novel Electron Trapping Materials (ETM) (ETM) SrS: Eu2+, Dy3+
Authors: Sun Jia Yue , Liu Zhen Xing , Du Hai Yan
Published: November 2010

A new electron trapping materials (ETM) SrS: Eu2+, Dy3+, which was prepared by the method of high temperature solid-state reaction. The results indicate that both ultraviolet light and visible light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 615 nm was detected. The up-conversion emission spectrum was found to be a continuous broadband spectrum resulted from the multi-transitions of Eu2+ 4f6→4f7 (8S7/2). The emission peak intensity of SrS: Eu2+, Dy3+ was stronger than SrS: Eu2+.
Electrochemical Characteristics of Lanthanum Hexaboride in the Environments Containing S2-
Authors: Zheng Shu Qi , Chen Chang Feng , Jiang Rui Jing , Wang Dan Ni
Published: November 2010

In the environment with H2S/CO2 or Na2S, the corrosion behavior of Lanthanum hexaboride (LaB6) was investigated by electrochemistry methods. The results indicated that the corrosion potential (Ecorr) and Rf of LaB6 increased as the partial pressure of H2S increased, while the corrosion current density (Icorr) decreased. In the environment containing Na2S, as the content of Na2S increased, the corrosion potential (Ecorr) and Rf of LaB6 decreased, while the corrosion current density (Icorr) increased. Thus, the addition of H2S into the environment with H2S/CO2 would inhibit the corrosion of LaB6; while in the environment containing Na2S, the increasing of the content of Na2S would accelerate the corrosion of LaB6.
Crystal Structure and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3) 0.92Zr0.08]O3-δ−xTiO2 Ceramics
Authors: Xiong Gang
Published: November 2010

Crystal structure and microwave dielectric properties of Ca[(Li1/3Nb2/3) 0.92Zr0.08]O3−δ−xTiO2(0≤x≤0.2) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.0~0.1. With an increasing of Ti4+ content, the Qf value decreased due to a decrease of the degree of B-site 1:2 ordering. However, the τf value firstly increased from-14.2ppm /°C to -6.6ppm/°C, and then moved to the negative direction. When x=0.05, the optimum microwave dielectric properties: εr=32.8, Qf =19460GHz and τf =−8.3 ppm/°C.
Research of Transparent Conductive Film Prepared with Polymer
Authors: Li Lu Hai , Xin Zhi Qing , Zhao Wen , Tang Xiao Jun , Du Peng , Hu Xu Wei , Leng Xian
Published: November 2010

In order to acquire conductive film with high transparency, conductive polymer PEDT: PSS was mixed with some polar dopants and some surfactants. The coating fluid was acquired and coated on the PET film with different coating rods, and conductive film was gotten after drying at some temperature. The conductive mechanism of polymer after doping was introduced. Furthermore, the influenced factors of conductivity were discussed, including different dopants and surfactants as well as dried temperature. It was concluded that DMSO and EG were the best dopants, that surfactants including fluoride or silicon were suited for high conductivity. The sheet resistance of conductive film can be less than 300 Ω/□ when dried at 130 oC, at the same time the transparency at 550 nm is more than 83%. After measuring with AFM, the surface of film was sharp and the surface roughness is 7nm.
Study on the Dielectric Properties of Phosphoric Acid-Based Geopolymers
Authors: Liu Le Ping , Cui Xue Min , He Yan , Yu Jun Li
Published: November 2010

The phosphoric acid-based geopolymers were synthesized using chemosynthetic Al2O3-2SiO2 and phosphoric acid at ambient temperature, curing for 28d at room temperature. The influence of the water from the geopolymer materials on the dielectric properties was investigated. The phase’s transformation was measured by XRD. The amorphous SiO2 from unreacted particles transformed to quartz crystal at 950 °C when exposure to 1350 °C, some mulite appeared, however, the dielectric properties change a little. After the geopolymer materials were heated at 350 °C, its dielectric loss could depress down to lower level of 10-3.
Spectral Analysis of Ca2-XBO3Cl:xDy3+ Phosphors
Authors: Huang Chun Ying , Wan Man Hua
Published: November 2010

PL spectra of Ca2-xBO3Cl:xDy3+ phosphors excited by 390 nm n-UV light. The intensity of both blue and yellow emissions starts to increases with the growing contents of Dy3+ ions, the strongest intensity of Dy3+ emission courses in the Ca1.95BO3Cl:0.05Dy3+ phosphor, subsequently it decreases with further adding Dy3+ ions due to concentration quenching. it can be concluded that the environment of Dy3+ ions may be less influenced due to the clustering of Dy3+ ions in the investigated phosphors after concentration quenching.
Synthesis and Characterization of the PANI/ITO Conducting Nanocomposites
Authors: Zhu Bing Jie , Wang Xin Wei , Zhu Mei Fang , Zhang Qing Hong , Li Yao Gang , Wang Hong Zhi
Published: November 2010

The PANI/ITO conducting nanocomposites have been synthesized by in-situ polymerization. The obtained nanocomposites were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared. Electrical conductivity measurements on the samples pressed into pellets showed that the maximum conductivity attained 2.0 ± 0.05 S/cm for PANI/ITO nanocomposites, at ITO doping concentration of 10 wt%. The results of the present work may provide a simple, rapid and efficient approach for preparing PANI/ITO nanocomposites.
Test Approach Based on Decision Diagrams for Delay Fault Caused by Crosstalk Interferences in Digital Circuits
Authors: Pan Zhong Liang , Chen Ling
Published: November 2010

The crosstalk is induced between the elements in digital circuits due the increasing switching speeds and the decreasing in technology scaling. The crosstalk is caused by parasitic couplings between adjacent wires that include capacitance and inductance effects. The crosstalk can result in functional failures or timing problems. A test approach for the delay faults caused by crosstalk interferences in digital circuits is presented in this paper, the approach is based on decision diagrams and the selection of delay sensitive path. The static timing analysis is carried out to obtain the delay information about the paths, all aggressor lines are activated in the best possible way. The test vectors are generated by building a decision diagram and searching for the specific paths in the decision diagram. Experimental results show that the test approach proposed in this paper can generate the test vectors for the testable delay faults caused by crosstalk.
Cooling Effects in Laser Forming
Authors: Shen Hong , Hu Jun , Yao Zheng Qiang
Published: November 2010

In the laser forming of metal plates, there is a substantial waiting time required for cooling down the workpiece so that a steep temperature gradient can be reestablished during the next scan. Currently, there are no standard techniques that can be used to reduce this waiting time. This paper discusses the possibility of using non-natural cooling systems to cool down the workpiece. A numerical model of thermo-mechanical analyses with moving boundary conditions to simulate the traveling of laser beam and moving forced water cooling system is presented. Based on the proposed model, cooling effects under different laser powers and scanning velocities with various cooling conditions are investigated. The results show that the forced water cooling can significantly reduce the temperature with no adverse effect on the forming of plates.
Effects of Different Metal-Molecule Interface Conformations on the Electronic Transport in Molecular Junctions
Authors: Xia Cai Juan , Zhang Ying Tang , Zai Xue Jun
Published: November 2010

Based on nonequilibrium Green’s function and first-principles calculation, we investigate the electronic transport of borazine molecule with different metal-molecule interface conformations, namely bridge and top site. The motivation is the variable situations that may arise in break junction experiments. Numerical results show that the current will be increased with the different adsorption sites; especially the enhancement of current is more obvious when molecule is located at the bridge site. Furthermore, a negative differential resistance under applied bias can be observed when the molecule is located at the top site. The mechanism of negative differential resistance is mainly induced by the resonance peak around the Fermi energy in top adsorption site.
First-Principles Study of Electron Transport Behavior through Porphyrin Molecular Wires
Authors: Li Yan Wei , Yao Jin Huan , Deng Xing Sheng , Huang Xiao Xi
Published: November 2010

The nonequilibrium Green’s function approach in combination with density-functional theory is used to perform ab inito quantum-mechanical calculations of the electron transport properties of porphyrin oligomers sandwiched between two gold electrodes. The results show that porphyrin oligomers are good candidates for long-range conduction wires. In particular, the decay of conductance of porphyrin oligomers does not follow the exponential relation. The electron transport behavior was analyzed from the molecular projected self-consistent Hamiltonian states and the electron transmission spectra of the molecular junctions.
Microstructure and Property Study of La2Mo1.5W0.5O9/Ag Composites
Authors: Li Chun , Li Da , Fang Qian Feng
Published: November 2010

Based on the oxygen ion conductor La2Mo1.5W0.5O9, a series of Ag2O doped samples La2Mo1.5W0.5O9/Ag were prepared with conventional solid-state reaction method. The effects of Ag2O doping on the microstructure and electrical conductivity have been investigated by XRD, FESEM and direct current conductivity measurements. With the increase of Ag2O doping, the grain was further refined and compacted, meanwhile, Ag diffusion distribution in the form of second-phase appear at grain boundary. The sample density and conductivity also gradually increased with the increasing of doping amount. The conductivity of the composite specimen La2Mo1.5W0.5O9 /Ag has a great enhancement when the concentration of Ag2O is around 27 wt%, which is eight times higher than that of the single-phase sample.
Relationship between Dopant 5-Sulfosalicylic Acid and Conductivity of Ammonium Persulfate Oxidized Polypyrrole
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai , Zhou Fu Fang , Pan Chun Xu
Published: November 2010

The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Being nonhygroscopic, ammonium persulfate was used as the oxidant. Under the condition of fixed molar ratio of oxidant-to-monomer (0.375:1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.375:1.00.
Optical Properties of Sr1-3x Al2O4 : Eu2+ XDy3+2x Phosphors
Authors: Huang Yuan Ming , Guo Ye Tang
Published: November 2010

A series of long persistent phosphors Sr1-3x Al2O4 : Eu2+xDy3+2x (X=0.005, 0.010, 0.015, 0.020, 0.025)were prepared through a combustion method at 600oC. We found that all the series of samples have good long afterglow properties by the naked eye. Then we use the laser to stimulate phosphors at 325nm, and their emission spectrums were tested by a spectrograph. We can found that the emission peaks of all samples are all results from the 4f65d  4f7 (8S7/2) transition of Eu2+ instead of the 4f7 (6P7/2)  4f7 (8S7/2) transition of Eu2+ ions. In addition, the afterglow characteristic of the various samples and the same sample at different wavelengths was investigated. Our results show that each decay curve consists of a rapid decay part followed by a long slow one and all samples have the same afterglow mechanism.
Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.15]O3+δ Ceramics with Sm3+ Substitution at A-Site
Authors: Xiong Gang
Published: November 2010

Crystal structure and microwave dielectric properties of (Ca1-xSmx) [(Li1/3Nb2/3)0.95Zr0.15]3+δ(0.0≤x≤0.2,CSLNZ) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.0~0.08. With an increase of Sm3+ content, the quality factor value firstly increased, and then began to decrease at x=0.03 due to a decrease of the degree of B-site 1:2 ordering. The variation of τf with tolerance factor was discussed. When x=0.05, the optimum microwave dielectric properties: the permittivity is 32.4，the quality factor is 16560GHz，and the temperature coefficient of resonator frequency is −6.3×10−6/°C。
Optimized Conductivity of Anthraquinone-2-Sulfonic Acid Sodium, 5-Sulfosalicylic Acid and Toluene-4-Sulfonic Acid Co-Doped Polypyrrole
Authors: Huang Yuan Ming , Ma Qing Lan , Kong Xiao Yan
Published: November 2010

By doping three complex dopants in different molar ratio, a series of polypyrroles doped with 9, 10-anthraquinone-2-sulfonic acid sodium, 5-sulfosalicylic acid and toluene-4-sulfonic acid were synthesized by polymerizing the monomer pyrrole in aqueous solution of ferric chloride. The resulting polypyrroles were characterized with the four-probe and laser light scattering, respectively. Our results indicate that optimized value of conductivity reached to 6683 S/m when the molar ratio of anthraquinone-2-sulfonic acid sodium to 5-sulfosalicylic acid to toluene-4-sulfonic acid was 2:1:3. For applications of polymer in optoelectronics, in lithium-ion battery and in electromagnetic shielding, to obtain optimized value of conductivity has great significance for us.
High Birefringence Photonic Crystal Fibers
Authors: Guo Shu Qin , Ge Min , Zhuang Pan , Chang Li Ping
Published: November 2010

Photonic crystal fiber (PCFs) offer new possibilities of realizing highly birefringence fibers due to a higher intrinsic index contrast compared to conventional fibers. Here, based on general section structure of PCFs, we take some mend in the core configuration, and achieve highly birefringence effect. A elliptic air hole and its inscribed circular high refractive material form the core of PCFs together. Especially to mention, they are being tangent at two points. By optimally selecting parameters, the effective refractive index difference between two orthogonal directions neff can reach the magnitude of 10-2. After numerical calculation, we find that increase the size of circular solid core, or long axe size of elliptic air hole, birefringence parameter of modal field can become more highly. Moreover, by matching structure parameters appropriately, the modal field diameters can be equivalent in the two orthogonal directions. A Gaussian modal field with highly birefringence character can be acquired.