bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Surface Roughness on the Adhesion of Elastomers to Hard Surfaces
Authors: Fuller Keith
Published: November 2010

The work presented started with the aim of trying to explain why clean smooth surfaces of materials such as metals brought gently into contact show no adhesion. The observation by Johnson Kendall & Roberts of adhesion between smooth surfaces of an elastomeric hemisphere and a rigid substrate suggested a model contact system with which the effect of surface roughness could be investigated experimentally. Moreover the Johnson-Kendal-Roberts (JKR) contact theory could be used to predict the effect of roughness on adhesion. The observations and predictions obtained are compared, and the implications for the contact of two rigid materials outlined. The limitations of the validity of the predictions are mentioned. Further studies of the adhesion to rough surfaces, in particular the phenomenon of enhanced adhesion at low roughness, will be discussed. Finally, more recent theoretical work is briefly referred to.
Study on the Tri-Functional Copolymer Containing 1,3,4-Oxadiazole, Carbazole and Terbium Complex
Authors: Wang Wen , Liu Li Juan , Lin Mei Juan
Published: November 2010

A novel tri-functional copolymer P1 containing hole transporting units, electron transporting units and terbium complex units was synthesized via radical copolymerization. It was characterized by DSC, TGA, Fluorescence, CV and I-V data test. The results showed that the copolymer P1 was capable of pure green emission in the solid state under UV excitation and had potential application in the memory or light-emitting device.
Study on the Corrosion Productions Formed on the Surface of Lanthanum Hexaboride in the Sour Gas Environments
Authors: Wang Peng Yan , Zheng Shu Qi , Chen Chang Feng , Jiang Rui Jing , Wang Dan Ni
Published: November 2010

The corrosion behavior of lanthanum hexaboride (LaB6) in the environment containing H2S and CO2 was studied. The results show that the corrosion of LaB6 was severe when the environmental temperature and the partial pressure of H2S were high, and the corrosion would preferentially happen at the central part of the sample due to the lower compact of this part.
Preparation of SnS2 Thin Films by Chemical Bath Deposition
Authors: Li Jing , Zhang Yong Cai , Zhang Ming
Published: November 2010

A chemical bath deposition method has been proposed for the preparation of SnS2 thin films onto glass slides from the aqueous solutions of tin (IV) chloride pentahydrate, thioacetamide and citric acid at 35 °C. High quality SnS2 thin films were obtained by adjusting the amounts of citric acid, which was used here as a complexing agent. The as-prepared thin films were characterized by Raman spectra, field emission scanning electron microscopy (FESEM), surface profiler and UV-vis absorption spectra. Raman spectra revealed that the as-prepared films were of hexagonal phase SnS2. FESEM images and surface profiler measurements indicated that the SnS2 thin film deposited under the optimum condition was homogeneous and well adhered to the substrate, with a thickness of about 200 nm. Optical absorption measurements disclosed that the SnS2 thin film deposited under the optimum condition had a band gap of about 2.40 eV.
Synthesis and Characterization of D-Galactopyranose-Containing Amphiphilic Block Copolymers via ATRP
Authors: Wang Xin , Dou Yuan Yuan , Pei Mei Shan , Tang Xin De
Published: November 2010

Biocompatible and biodegradable synthetic materials have attracted considerable attention during the past two decades. In this work, a series of amphiphilic triblock copolymers containing D-galactopyranose were synthesized by atom transfer radical polymerization (ATRP). The macroinitiator was prepared by the esterification between poly(ethylene glycol) monomethyl ether with a number-average molecular weight of 1200 g/mol (MeOPEO-1200) and 2-bromoisobutyryl bromide. The sugar-bearing monomer, 6-O-methacryloyl-1,2;3,4-di-O-isopropylidene-D-galactopyranose (MAIPG) was polymerized using PMDETA/CuBr as catalytic system and anisol as solvent. The chemical structure and composition of the resultant polymer MeOPEO-b-PMAIPG were verified by 1H NMR. The molecular weights and their polydispersities were characterized by gel permeation chromatography (GPC). The results indicate that the polymerization follows the mechanism of ATRP. The amphiphilic copolymers can self-assembly to from micelles with PMAIPG as the core and PEO as the corona, which have potential applications as biomaterials or controlled release drug delivery systems.
Fabrication the Texture Zinc Oxide Thin Films and its Application in Hydrogenated Amorphous Silicon Solar Cell
Authors: Hu Yue Hui , Xu Hai Jun , Gao Hao , Chen Yi Chuan
Published: November 2010

The pyramid-like textured ZnO film was prepared directly by magnetron sputtering on the self-supporting substrate of ZnO:Al film fabricated by sol-gel. The performance of amorphous silicon solar cell has been studied using the textured ZnO film as a front electrode. It was found that: (1) using the textured ZnO film as an amorphous silicon solar cell front electrode, it can be improved the open voltage, but the fill factor and conversion efficiency was depraved; and (2) inserting a protocrystalline silicon buffer layer between ZnO and p-a-SiC:H, the performance of solar cell was improved obviously. For example, its conversion efficiency increases from 7.3% for the SnO2: FTCO to 7.9% for the ZnO/pc-Si:H TCO.
Preparation and Properties of Zn1-XCoxO Magnetic Microspheres
Authors: Liu Zhi Fu , Zhang Qing Hong , Chen Li Yun , Li Yao Gang , Wang Hong Zhi
Published: November 2010

Zn1-xCoxO magnetic microspheres have been synthesized by a simple solvothermal process. Different Co2+ dopant concentrations have been used as modifier and proved to be efficient at controlling the morphology and magnetic property of Zn1-xCoxO microspheres. The as-synthesized samples are characterized by X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectrophotometer and vibrating sample magnetometry. Magnetic hysteresis loops reveal the samples exhibit ferromagnetic loops at room temperature. The meta-saturation magnetization value and coercivity of Zn0.8Co0.2O reach 0.09 emu·g-1 and 15.0 Oe.
Preparation and Characterization of Silver Myristate/AgBr Composite Particles
Authors: Li Ya Ling , Ning Jia Ning , Chen Yuan Mei , Liu Guang Fei , Zhang Guo Qing
Published: November 2010

Silver myristate/AgBr composite particles were prepared by using silver nitrate, sodium hydroxide, myristic acid, and sodium bromide as raw materials and PVP as surfactant in water-alcohol system and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), ultraviolet-visible spectroscopy (UV) and differential scanning calorimetry (DSC). The results showed that silver myristate/AgBr composite particles are composed of rod-like silver myristate grains with a layer structure and small silver bromide particles formed on the surface of silver myristate. Silver bromide can extend the ultraviolet absorbance range of silver myristate. The size of silver myristate is about 260nm and the average size of silver bromide is about 44nm. TG and DSC analysis showed that the reaction was carried out completely. The composite particles start to decompose at about 210oC. Silver bromide of the composite particles melts at 418.2oC.
Investigation and Preparation of the SCR Catalysts Nano-Co/Ce-V-Zr-TiO2
Authors: Ren Xiu Feng , Wang Fen , Zhou Yuan , Nian Hong En , Pang Yu Na , Wang Hong Bin
Published: November 2010

The nano-Co/Ce-V-Zr-TiO2 catalysts with the selective catalytic reduction (SCR) were prepared by methods of Sol-gel, impregnation (IM) and co-precipitation (CP). The phase compositions, microstructures and specific surface area of the catalysts were analyzed by BET, XRD and SEM, respectively. The effect of CeO2, CoO, V2O5 and V2O5 loading and reaction temperature on the catalytic performances of the as-prepared catalysts was investigated by using the selective reduction of NOx with NH3. The results showed all the as-prepared Co/Ce-V-Zr-TiO2 catalysts were made up of nanometer grains. Compared to conventional TiO2 catalysts, the as-prepared Co/Ce-V-Zr-TiO2 catalysts possessed better catalytic performance, higher adsorbability and larger area of contact with reactant, which is due to large quantity surface micropores. The NOx conversion of SCR over 8 wt%Co/Ce-V-Zr-TiO2 catalysts reached 98.3% at the reaction temperature of 550 oC. Furthermore, the activity of Co/Ce-V-Zr-TiO2 catalysts were improved by the Co loading, however, further increasing the Co loading lead to decrease the catalysis activity.
The Important Role of Oxidant in Copper Interconnection Chemical Mechanical Polishing for GLSI
Authors: Liu Xiao Yan , Liu Yu Ling , Niu Xin Huan , Zhao Zhi Wen , Hu Yi
Published: November 2010

Chemical mechanical planarization (CMP) of copper interconnection in hydrogen peroxide (H2O2) as oxidizer based alkaline slurry was investigated. The new model is put forward, which is based on the characteristic of H2O2, chemical kinetics and mechanical removal. This properties of H2O2 can be effectively compensated the defect of surface topology during the process of polishing. Researcher previous study has shown that the surface is largely copper metal with Cu2O at low H2O2 concentrations and largely CuO at high H2O2 concentrations. Cu2O is more easily removed by both chemical and mechanical processes than CuO. During the CMP process, as the oxidizer concentration increases, the removal rate goes up initially followed by a gradual decay. This characteristic of oxidizer is used to achieve copper surface global planarity. The surface planarity was achieved by removing high area on the surface more quickly relative to the low area, because the concentration of Cu2O in the low area as the passivation film is more than the high area. Meanwhile the passivation film of the low area is thicker than the high area. In order to achieve polishing process optimization, the influence of pH adjustment and pressure, are also taken into consideration. Combining both RR and PE, the optimal H2O2 concentration and pressures are in range 1.0 ~1.5 vol% and 0.04 ~0.07 mpa, respectively. The roughness of surface which is measured by AFM is 0.49 after CMP.
Growth and Etching Studies of MgO-Doped LiNbO3 Single Crystal
Authors: Li Xin Hua , Xu Jia Yue , Jin Min , Shen Hui , Lu Bao Liang , Wang Zhan Yong
Published: November 2010

LiNbO3 (Mg:LN) crystal is an important electro-optical material and MgO-doped LiNbO3 was expected to improve its optical damage resistance. In the present work, we reported the Bridgman growth of MgO-doped LiNbO3 crystal. The growth parameters were discussed and the defects were investigated by the chemical etching method. The etch hillocks and etch pits were observed on the negative Z surface while only etch pits on the positive Z surface by the optical microscope and EPMA. The etching morphology was discussed considering the domain structure.
Morphological Character and Statistical Property of Random Surface of ZnO Thin Film Prepared by RF Magnetron Sputtering
Authors: Zhang Ning Yu , Huo Qing Song , Han Li Xin , Fu Gang , Zhao Jun Qing , Wang Feng Xiang
Published: November 2010

A method for characterizing the morphology property of ZnO film surface with Gaussian correlation is investigated. The parameters of root-mean-square roughness w and lateral correlation lengthξare introduced in Gaussian model to describe the correlation properties of the random film surfaces. In the experimental performance, ZnO thin films are grown on quartz glass and silicon substrates by the reactive radio-frequency magnetron sputtering method under different deposition pressure. The surface morphologies of the film surface are scanned by an atomic force microscopy. The height auto-correlation functions and root-mean-square roughness are obtained by using the numerical calculus method. Carried on the fitting with the Gaussian function to the height auto-correlation function data, the lateral correlation lengths are extracted to describe the statistical properties of ZnO thin film in mathematics with other parameters.
Synthesis and Characterization of Silver Nanoparticles Coated Titanium Dioxide Nanowires
Authors: Zhang Kai , Yu Li , Lu Zhi Xin , Song Gang
Published: November 2010

For the sake of investigating the special optical character of heteronanostructures, we grow TiO2 nanowires following a three step synthesis method and coat silver nanoparticles on these nanowires with replacement method. Firstly, by adjusting the experiment parameters, we get the single crystalline titanium dioxide nanowires and control their length and diameter successfully. Secondly, we use the replacement method to make the silver nanoparticles coated on these nanowires. Finally, we use transmission electron microscopy and X-ray diffraction to characterize these productions and the results show that the silver nanoparticles are coated on the titanium dioxide nanowires uniformly and the components of these nanowires are only sliver and titanium dioxide. These new optical heteronanostructures are widely investigated all over the world and we sure that they can make great influences to the development of nanophotonics.
Controllable Luminescent Properties of Phosphors Sr2.97-XCaxMgSi2O8: Eu0.012+, Dy0.023+ by Adjusting Sr/Ca Ratio
Authors: Chu Jun Fu , Hu Yi Hua , Yin Hai Wang , Hao Yi Wu
Published: November 2010

Divalent europium and trivalent dysprosium co-doping in the compounds Sr2.97-xCaxMgSi2O8 (x=0, 0.5, 1.5, 2, 2.5, 2.97) produces phosphors of high luminescence yield. These phosphors were prepared at high temperature and weak reductive atmosphere. The ratio of Eu/Dy is 1/2. The phosphors were characterized for their crystal phases by x-ray powder diffraction. Slight shifts of the peaks in the structure, which indicate a small change of the interplanar crystal spacing, were observed for each different x’s. The interplanar spacing becomes narrow as increasing the value of x. These phosphors respond well to the ultraviolet excitation. The peak of the emission band occurs at progressively longer wavelength and widens as the ratio of alkaline earth Sr/Ca ions is decreased. The emission peaks of the phosphors indicated on the emission spectra range from 463nm to 490nm. It is probably due to the influence of 5d electron states of Eu2+ in the crystal field because of atomic size variation causing crystal defects. Dy3+ ion doping in the phosphor generates deep traps, which results in long afterglow phosphorescence. As the proportion of Ca in the composition increases, the attenuation time of the phosphors becomes short.
A New Method for Calculating the Velocity Resolution of Television-Based Detection System
Authors: Guo Qiang , Wang Feng Ge , Lu Xiang Yang
Published: November 2010

According to the definition, the calculation for the velocity resolution of a signal composed of several rectangular pulses is always complex, especially when it is a multiple-period signal. Apart from the definition formula of the resolution, the paper proposes a new fast algorithm for calculating velocity resolution by searching for the rows where the ‘half power value’ exists in ambiguity function matrix and then finding ‘half power point’ wide, avoiding the complicate and duplicated calculation and raising the efficiency.
Thermal Curable Silver Conducting Paste Used for the Preparation of the Tag Antenna Coils of the Radio Frequency Identification
Authors: Xu Wen Cai , Luo Shi Yong , Huo Li Xia , Zhang Xin Lin
Published: November 2010

A thermal curable silver conducting paste used for preparation of the tag antenna coils of the radio frequency identification (RFID) tag was presented. The typical composition of the paste was determined as (wt%): flake silver powder, 59.80, spherical silver powder, 5.20, organic vehicle solution, 35.00. The paste was screen printed on the substrates of papers, and then thermal cured at the peak temperature of 130~150 Celsius degrees for 60-120 seconds. The SEM image indicated that the cured film was perfectly flat and compact. The sheet resistance of the cured film was about 2 milli-ohms per millimeter square at the thickness of 25 micros determined by a four-point probe technique. The pencil hardness (H) of the cured film was more than 2H. In addition, the rheological behavior of the typical paste demonstrated shear thinning property. The thixotropy behavior shown that the silver particles in the paste have flocculated weakly at rest.
ZnO/SiO2 Nanocomposite Cryogels Prepared by Vacuum Freeze Drying
Authors: Su Li Fen , Miao Lei , Tanemura Sakae
Published: November 2010

In recent years, ZnO/SiO2 nanocomposite thin films have attracted much attention for a wide range of device applications based on their specific optical and electrical properties. Traditionally, the ZnO/SiO2 nanocomposites were prepared at the form of thin film because the ZnO/SiO2 nanocomposite gels are difficult to synthesize. Therefore, in the present study, a novel route of the mixed ZnO/SiO2 nanocomposite cryogels were prepared by sol-gel technology and dried by vacuum freeze drying. The wet gels were synthesized by co-precursor method with the precursors containing tetraethoxysilane [Si(OC2H5)4,TEOS] and zinc acetate [Zn(CH3COO)2.2H2O]. After vacuum freeze drying, the nanocomposites were annealed at different temperature. The properties of the resulting ZnO/SiO2 nanocomposite cryogels were characterized using Scanning Electron Microscopy (SEM), nitrogen absorption/desorption isotherms, thermogravimetric and differential scanning calorimeter (TG-DSC).
Effect of Different Washing Treatments on the Formation of Titanate Nanotubes
Authors: Liu Cheng Yan , Miao Lei , Huang Rong , Tanemura Sakae
Published: November 2010

Titanate nanotubes were successfully synthesized by means of an alkaline hydrothermal method and further appropriate post-treatments. The effect of different washing treatments on the formation of titanate nanotubes were systematically studied in this paper. It was found that the washing treatments play an important role in the formation of nanotubes. Treating with 0.1M NaCl aqueous solution mainly resulted in titanate nanosheets while treating with deionized water or 0.1M HCl aqueous solution (1 time, PH>7) can obtain highly crystallized titanate nanotubes. Furthermore, if the PH values of solutions after acid washing processes were below 7, trace of nanotubes can be found but almost all of them were damaged. On the basis of all the present experimental results, we can conclude that titanate nanotubes can be prepared as long as the driving force induced by the imbalance of sodium ion (Na+) concentration on two different sides of nanosheets was appropriate, and meanwhile they were instable in acidic solutions.
Thermal Expansion Property of P2O5 Doped Lithium Aluminosilicate Glass-Ceramic Synthesized by Sol-Gel Process
Authors: Xiao Zhuo Hao , Luo Wen Yan , Wang Sheng Long
Published: November 2010

Lithium aluminosilicate (LAS) glass-ceramics with 0 ~ 10 wt% phosphoric anhydride were prepared by sol-gel method and sintering at high temperature. Tetraethyl orthosilicate (TOES), aluminum nitrate, lithium carbonate were used as precursors. Differential thermal analysis (DTA), X-ray powder diffraction (XRD) and thermal expansion coefficient (TEC) were used to characterize the dried LAS gels and glass-ceramic blocks. The results suggest β-spodumene solid-solution is the only crystals phase in the P2O5 doped LAS glass-ceramics when sintering temperature is 950 oC. The thermal expansion coefficient of the P2O5 doped LAS glass-ceramics range from -0.1×10-6 oC-1 to 1.2×10-6 oC-1. Compared with the conventional melt quenching method, this process route provides a low temperature and timesaving method for preparing LAS glass-ceramics.
Effect of Heat Treatment Conditions on Microstructure and Infrared Transmission Property of Germanate Oxyfluoride Glass-Ceramics
Authors: Xiao Zhuo Hao , Wang Sheng Long
Published: November 2010

Germanate oxyfluoride glass in CaF2/BaF2-AlF3-SiO2-GeO2 was prepared by melt quenching technique and subsequently converted to glass-ceramics with microstructures comprised nano-crystallites in a residual glass matrix by two-step heat treatments process. DSC, XRD, SEM and IR transmission investigations were used to determine structural characteristics and optical property of the prepared germanate oxyfluoride glass-ceramics. The influences of heat treatment conditions on crystallization behaviors and infrared transmission were discussed. The results show that crystal phase in the glass-ceramics is only Ge2Al6O13 and the crystal size is about 20nm-80nm when treated temperature ranges from 900 oC to 960oC. Good transparency is exhibited in visible light band to midinfrared band (5.0um) when treated temperature is low than 940 oC.
Numerical Simulation and Experiment on Assemble Nozzles’ Flow Field in Laser Cutting
Authors: Hu Jun , Cao Qian Qian , Luo Jing Wen
Published: November 2010

Based on a convergent nozzle and a conical nozzle, the simulation of the free jet of assemble nozzles by adopting a three-dimensional axial symmetrical model is presented in the paper. The study reveals the effect of cone angle of conical nozzle and the parabola equation of convergent nozzle on flow field by adjusting nozzles’ interior figure parameters. The distribution of pressure and velocity of gas jet are shown in the investigation. A conical nozzle with cone angle of 30° and a convergent nozzle described by the parabola equation of y=0.207x2 are designed and produced for the laser cutting experiment. Numerical simulation and experimental results are given at the end of the paper.
Effect of Heat Treatment on Structural and Optoelectronic Properties of GaN Epilayers
Authors: Mei Jun Ping , Xie Xin Jian , Hao Qiu Yan , Liu Xin , Xu Jin Jin , Liu Cai Chi
Published: November 2010

GaN epilayers were grown on sapphire by metal-organic chemical vapor deposition (MOCVD), and the samples were annealed with rapid thermal processor (RTP) at 650, 750, 850 and 950oC, respectively. The effect of heat treatment on structural and optoelectronic properties of GaN epilayers was investigated. X-ray diffraction (XRD) analysis shows that the full width at half maximum (FWHM) of the rocking curves becomes smaller as the annealing temperature increases. Photoluminescence (PL) spectra at room temperature demonstrate that the yellow band decreases with the increase of annealing temperature. Hall-effect measurements reveal that carrier concentration of the GaN epilayers raise with the increase of annealing temperature. The results suggest that the structural and optoelectronic properties of GaN epilayers could be significantly improved by heat treatment.
Finite Element Analysis on the Fatigability of the 4G1 Engine Support with Software ANSYS
Authors: Fu Xiao Guang , Wang Xiao Jun
Published: November 2010

A complicated 3D model was established to solve the problem of the lifetime of an engine support. With the finite element analysis software ANSYS, we analyzed the fatigue problem for an engine support and derived the numerical values of the lifetime of a typical engine support. Our work provides the fundamental guidance to optimize the structure of the engine support.
Pavement Performance and Anti-Aging Property of Microscale Flyash/SBS Modified Asphalt
Authors: Tang Xin De , Kong Xiang Li , He Zhong Guo , Li Jun
Published: November 2010

Microscale flyash/SBS composite modified asphalts (CMA) were prepared by melt blending. Rolling thin film oven test (RTFOT) was employed to study the anti-aging property. Both flyash and SBS disperse homogeneously in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Moreover, microscale flyash plays a significant role in the CMA. The effect of flyash on the properties of SBS modified asphalt appears as a decreasing penetration, an increasing softening point, and a decreasing ductility. The anti-deformation ability under high temperature of the CMA improved significantly. In comparison with that of the base asphalt, the softening point of the CMA decreases after aging, which maybe attribute to the different rheological properties between the CMA and the base asphalt. Compared to that of SBS modified asphalt, the anti-aging property of CMA improved significantly. This demonstrates that the microstructure of flyash can prevent oxygen from diffusing and permeating.
Spin and Charge Currents from Applying a Microwave Field to a Quantum Dot
Authors: Zhou Yun Qing , Yao Jian Ming , Kong Ling Min , Wang Rui
Published: November 2010

The evolution operator approach is applied to studying photon-electron pumping effects on a quantum dot connected to two magnetic leads in the presence of both via-dot and over-dot tunneling channels. It is found that a microwave field applied to the quantum dot may give rise to charge and spin pumping at zero bias voltage for asymmetric magnetic junctions.
Origin of the Photoluminescence of a Banana-Shaped Liquid Crystal
Authors: Huang Yuan Ming , Zhai Bao Gai , Ma Qing Lan
Published: November 2010

We have investigated the optical absorption and photoluminescence (PL) of a classical banana-shaped liquid crystal, 1,3-phenylene-bis[4-(4'-nonyloxy)phenyliminomethyl]benzoate, in dilute solutions of tetrahydrofuran. Upon the 325 nm excitation from a helium-cadmium laser, the dilute tetrahydrofuran solutions of the banana-shaped compound gives off strong PL with its peak located at about 380 nm (3.26 eV). Interestingly the PL spectrum of the banana-shaped compound has a long tail that extends beyond 500 nm. In order to explore the origin of the PL, we have calculated the electronic structures of the three chromophores in the banana-shaped compound: the central benzene ring (chromophore A), the carbonyl linkage (chromophore B), and the Schiff base bridged two benzene rings in the branched arms of the molecule (chromophore C). Our results have shown that chromophore C is responsible for the 380 nm PL band where the chromophore B is responsible for the long tail in the recorded PL.
Measurement on Thermal Radiation of Standard High-Temperature Blackbody Furnace in Visible Spectrum Range
Authors: Lei Jian Bo , Chen Juan , Wang Zhen , Wang Yun Shan
Published: November 2010

Based Plank’s radiation law, thermal radiation intensity depends on radiation wavelength and material temperature. As the increase of material temperature, thermal radiation wavelength will decrease from infrared waves, next to visible light, last to ultraviolet light. In order to research the spectral distribution of molten pool at different temperature in laser fabricating, thermal radiation of standard BF1400 blackbody furnace in National Institute of Metrology of China was measured by CCD technique. Its high-temperature cavity radiators glow which was dim red at 600 oC, bright red at 800 oC, yellowish red at 1000 oC, bright yellow at 1200 oC. The thermal radiation in visible spectrum range could be acquired by CCD, which was translated into grey data of red, green and blue radiation intensity. It was shown that grey gain at red, green and blue wavelength was different greatly as increase of blackbody temperature, extremely large at red wavelength, little at blue and green wavelength. When thermal radiation of molten metal pool at red, green and blue wavelength in laser fabricating was acquired to analyze the relation between spectrum and temperature, the green and blue wavelength will be good choose for its colorimetry temperature analysis.
Preparation of Two Carbazole Derivatives and its Third-Order Nonlinear Optical Properties
Authors: Li Liang , Wu Yi Qun , He Chun Ying , Duan Wu Biao
Published: November 2010

Carbazole derivative is one sort of important nonlinear optical materials. In this work, new symmetric-type D-π-D carbazole derivatives, 3, 6 - di- substituted carbazole chromophores with two styryl bridges of the two-dimensional conjugated D-π-D system were synthesized via Witting reaction and characterized by IR, NMR and MS. The third-order nonlinear optical properties of the material were investigated using single-beam Z-scan technique with Sapphire femtosecond laser pulses at 800nm, repetition rate of 1 KHz and pulse width of 140fs. The results of Z-scan with and without an aperture showed that larger third-order nonlinear optical polarizabilities γ can be readily obtained in such carbazole chromophores because of the incorporation with two styryl bridges, increasing of conformational planarity and molecular conjugation length.
High-Performance Thin Film Encapsulation for the Application of White Organic Light-Emitting Diodes
Authors: Liao Ying Jie , Liu Ji Zhong , Zhang Yong , Li Long , Yu Fang Fang , Wei Bin
Published: November 2010

Color conversion method has been used to fabricate chromatic-stability white organic light-emitting diodes (OLEDs). Experimental results found little CIE coordinate migration while changing operation voltage from 5 V to 12 V. A simple thin-film encapsulation (TFE) structure has been developed through vacuum thermal deposition in combination with plasma enhanced chemical vapor deposition. The luminance of the encapsulated white OLED remain unchanged during the test time. The novel approach is being expected to lower the cost and achieve high-performance TFE.
Optical Properties of Lead Glass Doped with CdS/Se Compound
Authors: Won-In Krit , Pongkrapan Sorapong , Dararutana Pisutti
Published: November 2010

Lead-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 20-wt% commercial-grade PbO as the main compositions. A CdS/Se compound of ratios ranging from 1:1 to 1:10 was doped into the glass mixture. The dried powders were well mixed in a ceramic crucible before being melted in an electric furnace at a maximum temperature of 1100°C for 4 hours. Transparent and bubble-free glass samples were resulted after cooling down to room temperature. It was found that the glass colors were changed from colorless to reddish brown by the addition of CdS/Se compound. Physical properties of the samples, such as, color, specific gravity, and refractive index were studied. Specific gravity and refractive index increased with increasing ratio of CdS/Se. UV-VIS-NIR spectra were measured and discussed.
Synthesis and Photophysical Properties of Novel Polystyrene Derivatives Containing Oligofluorene Pendants
Authors: Hu Xiao Dan , Wang Shao Hong , Hou Zhao Xia
Published: November 2010

A series of novel polystyrene derivatives with oligofluorene pendants were synthesized by Friedel-Crafts reaction. The structure and properties of the polymers and monomers were characterized using NMR, UV-vis spectroscopy, DSC, photoluminescence and electroluminescence spectroscopy. The content of fluorescent units in OPS (oligofluorene grafted polystyrene) was proportional to the dosage of oligofluorene monomers in a wide scope. All the materials were soluble in common organic solvents and easily spin-coated onto the indium-tin oxide(ITO)-coated glass substrates. The polymers showed good fluorescent properties with comparely wide photoluminescent spectra. This method could be an easy way to obtain non-conjugated fluorescent polymers for photoelectric devices by solution processing. The electroluminescent properties of these polymers were reported briefly in this paper.
Field Emission Properties of ZnO Nanorods Synthesized by Aqueous Solutions
Authors: Gao Bo , Zhang Hai Ming , Zhu Yan Jun , Li Yu Jie , Hu Guo Feng
Published: November 2010

In this paper, we introduce a simple and effective method to prepare ZnO nanorods using aqueous solutions. The morphology and structure properties of ZnO nanorods were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL). The SEM results indicated that the diameter of ZnO nanoroads was about 100 nm. The XRD pattern showed that the ZnO nanorods had high-purity wuruzite structure. The PL spectrum revealed that ZnO nanorods had a strong visible emission at 423 nm. The field emission (FE) properties of ZnO nanorods were also studied. The FE results showed that the turn-on field and threshold field were 24V/μm and 39V/μm, respectively.
Aurora Intensity Conversion and Distribution Simulation
Authors: Tang Yuan He , Jia Qi Jie , Qin Lin , Duan Xiao Dong , Qu Ou Yang , Cao Xian Gang , Peng Tong
Published: November 2010

For the upper atmospheric wind field measurement, the conversion relations between the unit of auroral (airglow) intensity Rayleigh and illumination, luminance, height of atmosphere, the photon number are derived. The auroral volume emission rate (VER) of O(1S)557.7nm and O(1D)630.0nm with height is presented. The VER peak values are 668R and 2630R respectively. The results can provide theory for light illumination and brightness of detecting upper atmosphere.
Optical Constants of Al-Doped Er2O3 Films Prepared by Radio Frequency Reactive Magnetron Sputtering
Authors: Zhu Yan Yan , Fang Ze Bo
Published: November 2010

Al doped Er2O3 films were deposited on Si(001) substrates by radio frequency magnetron technique. X-ray diffraction and atomic force microscopy show the Al doped Er2O3 films obtained are amorphous and uniform. The optical constants are studied which shows a proper value of refractive index and a lower reflectivity, indicating it could be a usefully material for solar cells.
Photoreflectance of AlGaN/GaN Heterostructure Measured by Using Mercury Lamp as Pump Beam
Authors: Peng Yu Lien , Hsu Ru Lang , Wang Dong Po , Jiang I Min
Published: November 2010

Photoreflectance (PR) spectra of a GaN thin film and an AlGaN/GaN heterostructure were measured by using a HeCd laser or a mercury lamp as a pump beam. The wavelengths (λ) of the HeCd laser and the mercury lamp are 325 nm and 253.7 nm, respectively. The energy of the HeCd laser is lower than band-gap energy of AlxGa1-xN (x > 0.2), so electron-hole pairs cannot be generated in the AlGaN layer. Hence, the PR of the AlGaN was measured by using Argon ion laser (λ =300 nm) or quadrupled Nd:YAG (λ =266 nm) rather than HeCd laser in the previous works. In this work, the mercury lamp was used as the pump beam. Although the mercury lamp is a diffused source, it is not a hindrance to the PR measurements. The signal to noise ratio is improved by using defocused pump and probe beams in the PR measurement.
Structure and Optical Properties of ZnO Thin Film Preparation Using RF Magnetron Sputtering
Authors: Quan Shan Yu , Yang Lin Mei , Liu Cong , Zhang Xu Dong
Published: November 2010

The aim of this study is to obtain high-quality zinc oxide thin films by reactive radiofrequency (rf) magnetron sputtering. The thin films were prepared at constant total gas pressure, with different oxygen and argon contents. The ZnO samples were characterized by several methods. From XRD measurements it was confirmed that ZnO films are c-axis oriented, the line width and intensity are sensitive to O2/Ar gas pressure. All films exhibited excellent transmission (in excess of 70 %) in the visible range with a steep fall off in transmission at 425 nm. From the absorbance measurements the optical band-gap energy was extrapolated according the transmission spectrum. It shows that the optical band gap of the films increased from 3.233 eV to 3.288 eV with increase in the oxygen concentrations from 20 % to 70 %. Refractive indexes of the obtained thin films were carried out in this study.
Effect of Er and Yb Doping Concentration on the Luminescent Properties of Y2O2S:Yb, Er Phosphors
Authors: Han Peng De , Zhang Le , Chen Yan , Wang Li Xi , Zhang Qi Tu
Published: November 2010

Up-conversion luminescent materials of Y2O2S:Yb, Er with different doping concentrations of Er3+ ion (1 mol%–6 mol%) and Yb3+ ion (4 mol%–16 mol%) were prepared by flux method. As Yb3+ doping concentration was fixed at 8 mol%, when Er3+ doping concentration was 2 mol%, the green and red up-conversion luminescent intensity reached the maximum. As Er3+ doping concentration was fixed at 2 mol%, when Yb3+ doping concentration was 4 mol%, the green and red emission intensity reached the maximum. The up-conversion luminescent colours were adjustable.
Analyses of New Diffraction Optics Element Design by Polymer Gratings
Authors: Yarn Kao Feng , Chang Wen Chung , Chuang Wei Ching
Published: November 2010

A new diffraction optics element (DOE) which combines semiconductor laser and polymer-based DOE processing technology into a single optoelectronic polymer device is proposed. To directly combine the VCSEL (Vertical-Cavity Surface-Emitting Laser) with DOE, DOE surface profile can be integrated on the top of VCSEL utilizing polymer gratings by soft-lithography technique. Such a new kind of polymer-based DOE-VCSEL can control spatial distribution of emitting laser energy and output angle. Through the innovative development, it can be predicted that the optical loss and traveling distance in DOE system are decreased due to the shrinking the device volume by this new design.
Microwave-Assisted Hydrothermal Preparation of YVO4:Eu3+ Phosphor
Authors: Wang En Guo
Published: November 2010

YVO4:Eu3+ phosphors were prepared by microwave hydrothermal method in this work. YVO4:Eu3+ phosphors were probed by photoluminescence (PL), X-ray powder diffraction (XRD) and scanning electron microscope (SEM). The effects of different preparation conditions on the photoluminescence, the structure and the morphology of YVO4:Eu3+ phosphors were studied. The experiment results show that the pH value and the Eu3+ doping amount have some important effect on the photoluminescence and the morphology of YVO4:Eu3+phosphors.
Hetero-Epitaxial Defects and Optical Characteristics of SiCGe Layers Grown on 6H-SiC Substrate
Authors: Lin Tao , Lin Nan , Li Lian Bi , Yang Chen , Pu Hong Bin , Chen Zhi Ming
Published: November 2010

By means of SEM, TEM, UV-VIS optical transmission spectra and photoluminescence spectra tests, hetero-epitaxial defects and optical characteristics of SiCGe layers grown on 6H-SiC substrate were studied. SEM and TEM images have shown that the SiCGe were grown in layer-by-layer mode with APD and DPB defects which were caused by the thermal and lattice mismatches between SiCGe and SiC. Transmission spectra results have shown the calculated band gap of the SiCGe layer was 2.31eV. Room temperature photoluminescence spectra have shown that the peak wavelength and the FWHM of SiCGe layer were closely related to its Ge contents and the hetero-epitaxial defects.
Preparation of YVO4:Eu3+ Red Phosphor by Combustion Synthesis and its Luminescence Properties
Authors: Liang Zhen Hua , Lu Feng Qi , Liu Xiao Xia , Peng Gui Hua
Published: November 2010

YVO4:Eu3+ red phosphor was prepared by combustion synthesis without any post heat treatment at 700 oC-900 oC, using urea, oxalate acid and metal nitrates as raw materials. The product can emit bright red light under ultraviolet light irradiation. The phase compositions and luminescence properties were studied via X-ray diffraction (XRD) and photoluminescence spectra. The experimental results indicated that addition of appropriate amount of fuel and oxalate acid is favorable for the improvement of luminescence intensity.
Carbon Black-LaCoO3 Composite Material as Counter Electrode for Quasi-Solid-State Dye-Sensitized Solar Cell
Authors: Somsongkul Voranuch , Wongchaisuwat Atchana , Worayingyong Attera , Arunchaiya Marisa
Published: November 2010

Dye-sensitized solar cell (DSSC) is considered as the next generation low cost photovoltaic device, and one of the important components is the counter electrode which reduces the I3- ions generated after electron injection from iodide into the oxidized sensitizer. In this work composite material of carbon black and LaCoO3 synthesized by sol-gel method has been investigated to replace the platinized counter electrode for quasi-solid-state dye-sensitized solar cells. From cyclic voltammogram, it was found that carbon black catalyzed with LaCoO3 exhibited increased reduction current compared with that of carbon black without LaCoO3. This was consistent with increased surface roughness depicted from scanning electron microscopy (SEM) image. The electrochemical impedance spectroscopy (EIS) of DSSCs using carbon black-LaCoO3 composite as counter electrode revealed lower charge-transfer resistance (Rct) than that using carbon black. The highest conversion efficiency of 5.40% was obtained from DSSC (active area 1 cm2) fabricated with quasi-solid composite polymer electrolyte using carbon black-LaCoO3 (95:5 ratio by weight) compared to 5.23% obtained from DSSC equipped with platinum counter electrode. The performances of the quasi-solid-state DSSCs sensitized with N719 and natural dyes were examined and it was concluded that the carbon black-LaCoO3 composite was compatible with platinum coated counter electrode for DSSCs.
Evidence of Responsivity and Breakdown Voltage Improvement in SiCGe/SiC Phototransistor with Charge Compensation Layer
Authors: Cao Lin , Pu Hong Bin , Chen Zhi Ming , Lin Tao , Zhou Shao Jiang
Published: November 2010

An n-SiC/p-SiCGe/n-SiCGe heterojunction phototransistor with charge compensation layer has been simulated with commercial simulator MEDICI. With wide bandgap SiC emitter and p-type SiCGe charge-compensation layer, device responsivity and breakdown voltage has been improved. It is found that with p-type SiCGe layer, the responsivity is nearly two times of without one. Furthermore, flat electrical field distribution during off-state enable it supports higher reverse bias, thus breakdown voltage increased from 450V to 580V for the given structure, and both breakdown voltage and responsivity increase with light absorption region length.
Synthesis and Field Emission Properties of Hand-Like Bi2O3 Microcrystals
Authors: Lin Jin Yang , Zhang Yong Ai , Wang Ling Jie , Yang L. , Guo Tai Liang
Published: November 2010

A simple solution chemical route for bulk synthesis of hand-like Bi2O3 microcrystals has been demonstrated. The microcrystals are assembled by several short rods that have a diameter in the range of 50-500 nm, and a length in the range of 1-20 μm. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) were employed to characterize the structure and morphology of these novel structures. The field emission of the sample started at a turn-on field of 2.1 V/μm at a current density of 0.1 μA/cm2, while the emission current density reached about 0.1mA/cm2 at an applied field of 5.5 V/μm. These results suggest that hand-like Bi2O3 microcrystals can be an excellent FE material candidate.
The Quantum Length Dependence of Conductance in Molecular Device: An Ab Initio Study
Authors: Xia Cai Juan , Liu Han Chen , Zhang Ying Tang
Published: November 2010

By Applying Nonequilibrium Green’s Function Formalism Combined First-Principles Density Functional Theory, we Investigate the Electronic Transport Properties of Thiophene and Furan Molecules with Different Quantum Length. the Influence of HOMO-LUMO Gaps and the Spatial Distributions of Molecular Orbitals on the Electronic Transport through the Molecular Device Are Discussed in Detail. the Results Show that the Transport Behaviors Are Determined by the Distinct Electronic Structures of the Molecular Compounds. the Length Dependence of Molecular Conductance Exhibits its Diversity for Different Molecules.
Fabrication and Electrical Properties of Grain-Oriented 0.91Pb(Zn1/3Nb2/3)O3– 0.09PbTiO3 Ceramics
Authors: Cheng Wen Xiu , He X.Y. , Sun D.Z. , Zheng X.S. , Qiu P.S.
Published: November 2010

(200) grain-oriented 0.91Pb(Zn1/3Nb2/3)O3–0.09PbTiO3 (PMN–0.09PT) piezoelectric ceramics with a degree of orientation of 0.5052 have been produced from melt by a directional solidification method. The dielectric, ferroelectric, and piezoelectric properties were investigated, e.g., ε~4200, tanδ~0.8%, d33~2100pC/N, kt~58%, and k33~90%, some of these values are comparable to those of ~PZN–PT single crystals. The strain–electric-field curve with a maximum strain of 0.49% at a field of 7kV/cm and well-saturated hysteresis loops with a Pr~32 mC/cm2 were recorded. The results demonstrate that the directional solidification method is a promising technique to fabricate high performance grain-oriented PZN–PT ceramics.
Influence of the Distance between Target and Substrate on the Properties of TGZO Films Prepared by DC Magnetron Sputtering
Authors: Liu Han Fa , Zhang Hua Fu , Zhou Ai Ping
Published: November 2010

Ti-Ga co-doped ZnO thin films (TGZO) have been successfully prepared on glass substrates by DC magnetron sputtering at room temperature. The X-ray diffraction (XRD) patterns show that all the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The distance between target and substrate was varied from 41 to 75 mm. The crystallinity increases obviously and the electrical resistivity decreases when the distance between target and substrate decreases from 75 to 46 mm. However, as the distance decreases further, the electrical resistivity increases. It is obtained that the lowest resistivity is 2.0610-4cm when the distance between target and substrate is 46 mm. In the visible region, the TGZO films show a high average transmittance of above 90 %.
Preparation of Magneto-Optical Films TbFeCo by Magnetron Sputtering
Authors: Zhang Jin Min , Zhang Yong
Published: November 2010

The magnet-optical films of TbFeCo and Ag/TbFeCo were prepared on the Si substrates by magnetron sputtering. The spectra of Kerr ellipticity and Kerr rotation were measured at room temperature and the remarkable enhancement of Kerr effect was observed at short wavelength. The enhancement of Kerr effect is not caused by the interference between layers, but the resonance-like peak due to the presence of the plasma absorbing edge of Ag. The thickness of Ag layer has important influence on the enhancement of Kerr effect and the enhancement of Kerr effect will be disappeared as Ag layer is over than 50 nm.
Effect of LaCoO3 Additive on the Electrochemical Behavior of Zinc Anode in Alkaline Solution
Authors: Boonpong Rabat , Worayingyong Attera , Arunchaiya Marisa , Wongchaisuwat Atchana
Published: November 2010

The utilization of zinc anode for zinc-based battery is limited due to low cycling life, shape change and ZnO passivation on the electrode surface. The electrochemical behavior of zinc anode in the presence of the additives added to the electrodes or the electrolytes have been reported. In this work, LaCoO3 was used as an additive to improve the electrochemical properties of the zinc oxide anode. LaCoO3 synthesized by sol gel method (Schiff base complex) was added to zinc oxide powder (99.9%) with the weight ratio of 1:0.001, 1:0.002 and 1:0.003. The relative ZnO/LaCoO3 ratios were confirmed by particle induced x-ray emission (PIXE) technique.The electrochemical behavior of the ZnO/LaCoO3 electrodes in 6M KOH solution were investigated by voltammetry and electrochemical impedance spectroscopy (EIS). The cyclic voltammogram showed that ZnO/LaCoO3 gave higher anodic current and ZnO passivation delayed. The EIS spectra showed that charge transfer resistances of the ZnO/LaCoO3 anodes due to zinc oxidation were higher than that of ZnO electrode
Theoretical Investigation on the Electron Transport through Single Alkandithiol Molecules under Different Compression
Authors: Yao Jin Huan , Li Ning , Xiao Jian Rong , Li Yan Wei
Published: November 2010

The influence of molecular compression on the electron transport through single alkandithiol molecules sandwiched between two gold (111) electrodes has been studied by nonequilibrium Green’s function technique combined with density functional theory. The results showed that the molecular compression may increase the molecular current under low bias while decrease the molecular current under high bias. The mechanism of the effect of molecular compression on the electron transport behavior has been discussed in terms of electronic structures and transmission spectra.