bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology of Ultrasonic and Pulse Electrodeposition for ZnSe Thin Films
Authors: Zhang Cheng Guang , Li Kong Zhao , Miao Juan
Published: November 2010

The ZnSe thin films are co-deposited in the ZnSO4, Na2SeO3 and sodium citrate acidic solution, and the mechanism of the ultrasonic and pulse electrodeposition for ZnSe films is explained by the electrode-solution interface action model. Ultrasonic increases the activation energy of the [ZnCit]- and HSeO3 - and improves flow field of the solution between electrode and solution interface. The pulse current promotes the diffusion of solution and advantageously realizes the co-deposition of ZnSe films. The ZnSe thin films are pulse electrodeposited in zinc sulfate, selenite sodium and sodium citrate acidic solution with the action of ultrasonic. Finally, the ZnSe films have been characterized by the scanning electron microscope (SEM), the energy dispersion analysis of X-ray (EDAX) and X-ray diffraction (XRD).
Template-Free Sonochemical Preparation of ZnO Cauliflower-Like Microstructures
Authors: Deng Chong Hai , Hu Han Mei , Wang Shang Lin , Shao Guo Quan
Published: November 2010

Cauliflower-like ZnO superstructures composed of nanoparticles in large scale were successfully synthesized only using Zn(CH3COO)2•2H2O and triethanolamine (TEA) aqueous solution mixtures via a template-free sonochemical process at the ambient condition. A number of techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-visible absorption and photoluminescence (PL) were used to characterize the obtained ZnO products. It has been interestingly found that UV-Vis absorption spectrum shows not only a weak and sharp peak at 367 nm in ultraviolet region but also a strong and broad band centered at 564 nm in visible region. The possible formation mechanism of ZnO cauliflower-like structure is also proposed.
The Stochastic Resonance of the Single-Mode Laser with the Color Noises Correlation Period Modulation and Signal Modulation
Authors: Yan Xu Dong , Chen De Yi
Published: November 2010

The stochastic resonance of the laser systems which the color noise correlation intensity is modulated by the time period and the noise is modulated by the signal is investigated. By means of the linear approximation method, we calculate the signal-noise ratio of the laser intensity. We discuss the influence of the noise to the evolution of the signal-noise ratio with the noise self-correlation time, and discuss the influence of the signal modulation frequency to the evolution of the signal-noise ratio with the pump noise self-correlation time. It is found that the quantum noise and pump noise present different influence, the influence of the signal modulation frequency is interrelated with the time period modulation frequency.
Preparation of Starch Polyacrylamide Graft Copolymer and its Application in Paper Packaging Material
Authors: Liu Quan Xiao , Xu Wen Cai , Li Jin Li
Published: November 2010

The influences of concentration of initiator, reaction temperature, concentation of monomer and reaction time on the graft rate, the graft efficiency and the monomer conversion rate of starch polyacrylamide graft copolymer were studied by orthogonal trials, and the corresponding optimum conditions were investigated firstly. Then the synthesized starch polyacrylamide graft copolymer was used to treat waste water from the bleaching workshop of one papermaking mill. Finally the first pass retention of furnish to make paper packaging material and the influences of starch polyacrylamide graft copolymer on the mechanical properties of paper packaging material were investigated. It shows that the first pass retention of furnish to make paper packaging material with the increase of dosage of starch polyacrylamide graft copolymer. With the increase of dosage of starch polyacrylamide graft copolymer, the tensile strength, the breaking length of paper packaging material increase, but the tear strength and the folding endurance decrease.
Trace Addition of Ammonia and Water on the Growth of Cabon Nanotubes Prepared by PECVD Method
Authors: Fu Ya Bo , Xu Wen Cai , Li Dong Li
Published: November 2010

A new way was developed to grow carbon nanotubes (CNTs) in the downstream zone of high pressure dielectric barrier discharge plasma. Using Ni coated Si as the catalyzed substrate, CH4 as the carbon source, H2, NH3 and water vapor mixtures as the dilution and etching gas, CNTs were grown under temperatures of 630oC and 750 oC. The effects of various etching gas mixtures on the growth of CNTs were investigated respectively. The CNTs were characterized by SEM and high-resolution TEM. The results show that trace addition of Ammonia and water vapor to the plasma atmospheres can influence CNTs growth strongly. In 15% CH4 gas mixtures, CNTs can grown well within an addition of 3% NH3 which showed an improvement of CNTs quality, but no product was founded when adding the NH3 content over 8%. On the contrary, in 15% CH4 and 8% NH3 gas mixtures, CNTs can grow better when adding a small proportion (2‰-6‰) of water vapor to the etching gas and meanwhile optical emission spectrometry (OES) was applied to diagnositic and explain the effects of trace water vapor on the process of CNTs growth.
Syntheses and Thermo-Decomposition Process of the Co-Doping VO2(M) Precursor
Authors: Bi Ai Hong , Zhu Jin Hua
Published: November 2010

The precursor doped with W6+ and Mo6+ ionic was prepared using oxalic acid as reduction acid, V2O5 as vanadium source, (NH4)6W7O24·6H2O and (NH4)6Mo7O24·4H2O as doped sources. The morphology, composition, structure and the thermo-decomposing process of the precursor were characterized by means of SEM, EDS, FTIR and DSC/TG/DTG. The thermal decomposition was confirmed by XRD.
Structure and Piezoelectric Properties of (1-X)K0.49Na0.51NbO3-XLiTaO3 Lead-Free Piezoceramics
Authors: Li Yue Ming , Jiang Liang , Shen Zhong Yang , Liao Run Hua , Wang Zhu Mei
Published: November 2010

Lead-free (1-x)K0.49Na0.51NbO3-xLiTaO3 (x=0.00-0.07) piezoceramics were fabricated by the conventional solid-state sintering method, the effects of LiTaO3 content on the phase structure and piezoelectric properties of the ceramics were investigated. All the ceramics show single perovskite structure with a phase transition from an orthorhombic symmetry to a tetragonal one across an orthorhombic-tetragonal coexistence region with 0.04<x<0.06. For the ceramic sample with x=0.05, due to the coexistence of orthorhombic and tetragonal phases near room temperature, enhanced piezoelectric constant d33=236 pC/N and planar electromechanical coupling coefficient kp=40.9% are observed. In addition to other good electrical properties such as εr=969, tgδ=0.015 and Qm=41, this ceramic is a promising lead-free piezoelectric material.
Studying the Quantum-Well Structural Photonic Crystal with Odd-Number Channeled-Filterring Phenomena
Authors: Lu Qiang Hua , Gao Ying Jun , Su An
Published: November 2010

With properly chosen structural parameters, the transmission spectra of the mirror symmetrical model of photonic crystal (AB)m (CD)n (BA)m is calculated by means of transfer matrix method. When the transmission band of photonic crystal (CD) is inside the band gap of photonic crystal (AB)m (BA)m, both sharing the same central frequency as their symmetry centers, mirror symmetrical photonic quantum well is formed. At both sides of the central frequencies in the reduced units in the transmission spectra of the well, there are odd resonance-peaks, which symmetrically distributed and orderly localized, and show an obvious quantization effect for transmission-peaks. The number and location of the transmission peaks can be modulated by changing the number of period n of photonic crystal (CD). This can be used for designing the adjustably odd-passaged optical filters.
Synthesis of Yb3+/Tm3+Co-Doped MF2 (M=Ca,Sr,Ba) Nanocrystals with Blue Up-Converted Fluorescence
Authors: Du Hai Yan , Xian Jian Bo , Zhang Xiang Yan , Sun Jia Yue
Published: November 2010

A series of MF2:Yb3+/Tm3+(M=Ca, Sr, Ba) upconverted nanocrystals were synthesized by hydrothermal method. Polyvinylpyrrolidone(PVP) is an surfactant which can render the nanocrystals dispersible in water and ethanol. Upconverted emission was also detected in the red and NIR regions of the spectrum and assigned to the 1G4-3F4 (centered at 650 nm) and 3H4 -3H6 (centered at 800 nm) transitions, respectively. In addition, MF2:Yb3+/Tm3+ NCs show bright blue upconverted emission under the 980 nm excitation. As-synthesized MF2:Yb3+/Tm3+ luminescent NCs might find some potential applications in areas of photoluminescence and displays
Optical and Transport Properties of as Prepared and Annealed Te-Substituted Sn-Sb-Se Thin Films
Authors: Chander Ravi , Thangaraj R.
Published: November 2010

Thin films of Sn10Sb20Se70-XTeX (0≤X≤8) composition were deposited using thermal evaporation technique. As-prepared films were amorphous as studied by X-ray diffraction. Surface morphology studies revealed that films have surface roughness ~2 nm and av. grain size ~ 30 nm. Optical band gap Eg calculated from transmittance and reflectance data showed a sharp decrease for initial substitution of Se with Te upto 2 at%. Further substitution upto 4 at%, lead to a small increase in Eg value and thereafter it marginally decreased for further substitution beyond 4at%. The trend of optical band gap variation with tellurium content has been qualitatively explained using band model given by Kastner. The dc-conductivity measurements showed thermally activated conduction with single activation energy for the measured temperature regime and followed Mayer-Neldel rule. The dc-activation energy has nearly half the value as that of optical band gap that revealed the intrinsic nature of semiconductor. The annealing below glass transition Tg led to decrease in optical band gap as well as dc-activation energy that might be related to increase of disorder in material with annealing.
Preparation of YVO4:Eu3+,Ln (Ln = Bi3+, La3+, Li+) Red Phosphors by Combustion Synthesis and their Luminescence Properties
Authors: Liang Zhen Hua , Lu Feng Qi , Zhang Hai Long , Peng Gui Hua
Published: November 2010

YVO4:Eu3+,Ln (Ln = Bi3+, La3+, Li+) red phosphors were prepared by combustion synthesis, and effect of the Bi3+, La3+, Li+ doping ions on luminescence properties was studied. After doping with Bi3+, the emission intensity, excited by 322nm UV, decreased, but the absorption at 365nm was effectively enhanced; the brightness was increased by doping with La3+ or Li+, and the emission intensity at 619nm for YVO4:0.05Eu3+,0.15 Li+, excitation at 322nm, was about 160% of that for YVO4:0.05Eu3+.
Transmission Spectra of Quantum-Well Structured Photonic Crystals with Positive- or Negative- Refractive Index Materials
Authors: Lu Qiang Hua , Gao Ying Jun , Jiao Mei Na
Published: November 2010

By means of the transfer matrix method, transmission spectra and dispersion relationships of photonic crystals (AB) m (CD) n (AB) m (CD) n (AB) m are investigated herein. The number and highness of transmission peaks are found to relate closely with the repeating periodicity n, and (CD)n medium of positive- or negative- refractive index as well. The results may be helpful for designing optical filters of desired properties.
Investigation of Optical Properties of ZnO Films Deposited by RF Magnetron Sputtering
Authors: Li Shuang , Wang Feng Xiang , Fu Gang , Ji Yan Ju , Zhao Jun Qing
Published: November 2010

ZnO thin films with a strong c-axis orientation have been successfully deposited on quartz glass substrates at room temperature by radio frequency (rf) magnetron sputtering technology. X-ray diffraction, Rutherford backscattering, and prism coupling method were used to investigate the structure and optical properties of ZnO thin films. X-ray diffraction results shown lower sputtering pressure is propitious to increasing the crystallinity, and enhancing the c-axis orientation of the films. Rutherford backscattering analysis revealed that the films were stoichiometric ZnO, and as the sputtering pressure decreasing, the deposition rate were increased from 0.758 3nm/min to 2.892 nm min for sputtering pressure in the range from 1.0Pa to 0.5Pa. Under the lower sputtering pressure (0.5Pa) condition, the results obtained by prism coupling method investigation confirmed that the effective refractive index of ZnO films (no=1.8456，ne=1.8276) at a wavelength of 633nm is more close to Crystal Refractive index.
The Luminescence Property Study of CdTe/PMMA Emitting Green Light under Visible Light
Authors: Wang Wen , Huang Li Mei , Lin Mei Juan , Yang Ke You
Published: November 2010

The polymerizable monomer encapsulating CdTe quantum dot was synthesized by the electrostatic reaction. Then CdTe/PMMA was successfully obtained via free radical bulk copolymerization with the mixture of the polymerizable monomer and methyl methacrylate, which emit green light under visible light. The structure and optical properties of CdTe/PMMA were investigated by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Uv-vis absorption spectrum, and fluorescence spectrum, respectively. The results indicated that the CdTe/PMMA emit green light under ultraviolet and visible region (380-500nm). When the polymerizable monomer encapsulating CdTe quantum dot was 1.2%, the fluorescence quantum yield of CdTe/PMMA was 7.1%.
Combustion Synthesis and Photoluminescent Properties of Ca3((P,V)O4)2: Eu3+ Nanophosphor
Authors: Wang Xiao Jun , Zhou Xiao Chun
Published: November 2010

A simple combustion process has been proposed to systematically synthesize Ca3((P, V)O4)2: Eu3+. All the Ca3((P, V)O4)2: Eu3+ products were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spect rophotometer. The results indicate that Ca3((P, V)O4)2: Eu3+ phosphor particles is special morphology with quadrate of length 2.5 μm and breadth 1 μm. From the photoluminescence spectra for Ca3((P, V)O4)2: Eu3+, the remarkable emission transition 5D0 – 7F0 are assigned to Eu3+ ions substituted for Ca2+, and the most intense emission transition 5D0 – 7F2 indicates at noncenter symmetrical environment for Eu3+ ions. It was observed that the spectral features possess sharp and bright emission for a red emitting nanophosphors potential applications.
Research on the Eye Controlled Model of Anti-Glare Imaging Detector Based on Liquid Crystal
Authors: Zhang Huan Huan , Tang Yuan He , Yang Xu San , Wang Shui Wei , Xu Yong Kui , Liu Yao , Zhang Xun , Gao Gang , Yang Zhi Kai , Wang Tan
Published: November 2010

According to the optical-electric properties of liquid crystal, an eye controlled focus (ECF) anti-glare imaging detector is designed. Considering the existed concept of point metering controlled by the eye, a new concept of photometry, point-by-point single-pixel metering controlled by the eye, is brought forward. The method of ECF in the detector is researched. Firstly the pupil’s image is attained, and then the detector focuses with the focused function. Besides, a distinct image and a vague one are processed. The focused function values of the two images are 8.5057×103 and 7.2381×103 respectively.
Photostimulated Luminescence Studies of Electron Trapping Materials SrS:Eu2+,RE (RE= Dy3+,Yb3+,Pr3+,Ho3+,Tm3+)
Authors: Du Hai Yan , Liu Zhen Xing , Sun Jia Yue
Published: November 2010

Trivalent rare-earth ions, Dy3+, Yb3+, Pr3+, Ho3+, Tm3+, have been investigated as the co-doped auxiliary sensitizer for the electron trapping materials SrS:Eu2+ in order to enhance the fluorescence properties. It is found that Dy3+ and Ho3+ has the optimum photoluminescence stimulated luminescence (PSL) effect among the selected trivalent rare-earth ions. All the SrS: Eu2+ samples coped by different trivalent rare-earth ions can be stimulated by 980 nm laser after exposing to the conventional sun light, and they emit PSL with the peak located at 615 nm. The present research also indicates that some co-doped rare earth ions can increase fluorescence intensities of the traditional electron trapping materials SrS: Eu2+.
Synthesis and Luminescent Properties of Novel Polythiophene Derivatives with 1,3-Dioxane Group
Authors: Li Rong , Jiang Yu Jiao , Chen Fei , Mao Hong Lei , Wang Yong Hong , Zhong Guo Lun
Published: November 2010

Two novel polythiophenes with 1,3-dioxane group in the side chain named poly[3-(1,3-dioxane-2-ylethyl)thiophene] (PDT) and poly[3-(1,3-dioxane-2-ylethyl)-4-methyl- thiophene] (PDMT) were synthesized via oxidative polymerization firstly to form their precursor polymers and substitution secondly to obtain the target polymers in this paper. The chemical structures, molecular weights, thermal properties of the polymers were characterized by 1H NMR, FT-IR, GPC, and TGA respectively, indicating that both polymers had high molecular weight and good thermal stability. Meanwhile, the optical absorption and photoluminescence (PL) of both polymers were investigated and the results showed that the maximum absorption and emission wavelengths of PDMT were blue-shifted than that of PDT due to its methyl-substitution at 4-position in thiophene.
Efficient Photoluminescence from Thin Films of Polypyrrole
Authors: Huang Yuan Ming , Zhai Bao Gai , Ma Qing Lan
Published: November 2010

A soluble polypyrrole without any substituent groups was obtained by controlling the oxidation level of polypyrrole in the presence of oxygen. Upon the exposure to the 325 nm ultraviolet excitation from a helium-cadmium laser, thin films of the non-substituted polypyrrole could give off strong photoluminescence with its peak at about 530 nm. To elucidate the origin of the recorded strong photoluminescence, we measured the absorption spectra of the polypyrrole thin films with ultraviolet-visible absorption spectroscopy and our data indicated the appropriately oxidized polypyrrole are free of polarons. With the help of the electronic structures calculated with Hückel tight-binding method, the intense photoluminescence is interpreted in terms of the direct electronic transitions from the conduction band to valence band of the conjugated polymer.
Fabrication and Properties of Zinc Silicate Long Afterglow Phosphors
Authors: Jiang Guo Jian , Xu Jia Yue , Shen Hui , Zhang Yan , Xu Lin He , Zhuang Han Rui , Li Wen Lan
Published: November 2010

Zinc silicate-based (Zn2SiO4:Eu3+) long afterglow phosphors were fabricated by combustion synthesis and annealing method. The effects of different Zn sources, annealing temperature, Eu3+ additive on the properties of the combustion products have been studied. The results show that, the product is white with ZnO as zinc source while that from Zn(NO3)26H2O is slightly yellow. At higher annealing temperature, the sample is purer. Small amount of Eu2O3 additive did not change the phase composition. The fluorescence spectroscopy shows that, the emission peak of the sample with Eu3+ additive located at 620nm.
Exploration in the Two-Photon Absorption Effect of Silicon Based Films
Authors: Yang Ming , Li Juan , Yao Ying , Yin Chun Jian , Wu Chun Ya , Zhu Xiao Nong , Xu Zhi Jun , Xiong Shao Zhen
Published: November 2010

In this work, the crystallization of different silicon based thin films as the precursor of crystallization was investigated by femto-second laser with 800 nm wavelength. The linear absorption coefficient of a-Si films at that wavelength is quit lower than the other structures of Si-based thin film, which has no related with the incident light energy. However, we found that the crystallization of a-Si films was better than μc-Si films as the precursor. We use Z-scan techniques to prove that the two-photon absorption effect would be responsible for the crystallization. And unlike the linear absorption, the two-photon absorption effect is correlated with the incident light energy, as well as the micro-structure of the silicon based film. At the end of the paper, the crystallization by laser with wavelength longer than the absorption limit was discussed.
Structural and Photoluminescent Properties of Li-Doped ZnO Film Prepared by Sol-Gel Technique
Authors: Cheng Peng Fei , Li Sheng Tao , Liu Han Chen , Song Li Xun , Gao Bin , Wang Qiu Ping
Published: November 2010

The effect of an impurity as a donor or an acceptor in ZnO film is determined by its distribution in ZnO lattice. In this paper the distribution of Li is investigated by X-ray diffraction (XRD) and photoluminescence (PL). It is found that Li-doped ZnO films own different dependence on heat treatment temperature by contrast with pure ZnO films. For Li-doped ZnO films, although the crystallinity is promoted after heat treatment at 500oC, it is impeded effectively after heat treatment at 600oC. The abnormal phenomenon implies that Li preferential inhabits at Zn-sublattice to form a substitutional defect as an acceptor unless Li content exceeds its solubility in Zn-sublattice. The change of the PL spectra of pure ZnO films after heat treatment at different temperatures reveals that the PL peak at 650nm origins from interstitial defects. Moreover, with the increase of Li content, the intensity of the peak at 650nm decreases firstly and then increases again. This interesting changing trend further reveals that superfluous Li will enter into the octahedral interspaces as donors. As a conclusion it is proposed that it is difficult to obtain high conductive p-ZnO by monodoping of Li.
Fabrication and Luminescence Properties of CaMoO4:Eu3+ Red Phosphors for White LED
Authors: Liang Zhen Hua , Feng Yu Zhi , Liu Xiao Xia , Peng Gui Hua
Published: November 2010

CaMoO4: Eu3+ red phosphors were synthesized by co-precipitation method with H3BO3 as an additive and the relationship between H3BO3 doping amount and luminescent properties were studied. The brightness increased with increasing H3BO3 amount, the brightness of the CaMoO4: Eu3+ powder with 10 mol％ H3BO3 was 3.2 times higher than that of the phosphor without H3BO3.
Protonation Degree of Doped Polyaniline with Sulfosalicylic Acid as Function of the Synthetic Method
Authors: Huang Hui , Guo Zhong Cheng , Li Ju Kang , Chen Bu Ming
Published: November 2010

X-ray photoelectron spectroscopy (XPS) has been employed to investigate the protonation degree of polyaniline doped with sulfosalicylic acid (PAni-SSA) obtained by different synthetic methods. The protonation degree has been compared to electrical conductivity. Prepared PAni-SSA through the redoping process in an agate mortar displays conductivity values within the range of 1S/cm. Protonation degree of synthesized PAni-SSA by aqueous dispersion polymerization of aniline in the presence of SSA is higher than 50 %, indicating that a substantial portion of amine units have also been protonated. The C/N and S/N molar ratios obtained by XPS analysis indicate that the polyaniline chains obtained by aqueous dispersion polymerization are protonated by both sulfate anions.
Controllable Spin-Polarization of Electronic Transport through a Magnetic Quantum Dot in the Influence of Microwave Field
Authors: Zhou Yun Qing , Yao Jian Ming , Kong Ling Min , Wang Rui
Published: November 2010

The evolution operator method is applied to studying the time-dependent and spin-related electron transport through a magnetic quantum dot coupled to two normal-metal leads. When the microwave field is applied on quantum dot there are additional peaks of PAT current besides the main peak of resonant tunneling current, and the energy distance between peaks relate to the frequency of microwave fields. Furthermore, owe to the spin non-degeneration in the magnetic quantum dot, the spin-up and spin-down current peaks are separated, and the separated distance depends on Zeeman energy. These effects allow us to propose a scheme to control the magnitude and spin polarization of current.
Synthesis and Properties of Conducting Polyaniline by Co-Doping with Sulfosalicylic Acid and Sulfate Acid
Authors: Huang Hui , Guo Zhong Cheng , Li Ju Kang
Published: November 2010

A chemical oxidative polymerization of aniline sulfosalicylic acid (ANISSA) and aniline sulfate acid (ANIH2SO4) was performed in an aqueous solution. A co-doped polyaniline (PANI) was thus obtained, a higher conductivity than the insoluble H2SO4-doped PANI compressed pellet, and much higher conductivity than that prepared from pure ANISSA. The PANI doped with SSA and H2SO4 was characterized using Fourier-transform infrared spectra (FTIR), Fourier-transform Raman spectra (FT-Raman), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The investigation reveals that SSA and H2SO4 as dopant not only enhances crystallinity of polyaniline but also stability of polyaniline.
Effect of Deputy Group Metal Ions on the Fluorescent Properties of the CPPO-H2O2-Rhodamine B System
Authors: Du Hai Yan , Xu Wei Da , Zhou Wei , Sun Jia Yue
Published: November 2010

The influence of metal ions on the peroxyoxalate chemiluminescence reaction was investigated. A number of metal ions showed the quenching effect of the chemiluminescence reaction of bis (3, 5, 6- trichloro-2-carbopentyloxy) oxalate with hydrogen peroxide in the presence of Rhodamine B as the fluorophore. Copper ion gave the highest quenching effect. The reason for the decrease in the chemiluminescence intensity by metal ions is probably a change in the conjugative structure of Rhodamine B due to combination of metal ions and Rhodamine B
Research of Activated Carbon for Supercapacitor Prepared by Organic Template Method
Authors: Fang Qin , Wang Ren Qing , Deng Mei Gen
Published: November 2010

Activated carbon was fabricated by using phenolic resin as carbon source, PEG as organic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy (SEM). Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the specific surface area of the prepared sample (AC1) was 2469 m2/g, the pore size was mainly in the range of 1.0～4.0 nm. At a current density of 7.5 mA/cm2, a specific capacitance of 327F/g was achieved, the equivalent series resistance (ESR) was 0.8Ω. Supercapacitors based on the sample have low ESR and excellent power property. For comparison, commercial AC (AC2) was also studied.
Implementation of ZnO Nanorods as Sensing Elements for a Surface Acoustic Wave Sensor
Authors: Dee Chang Fu , Aw Kean C. , Wright Bryon , Yan Xiao Dong , Zou Chong Wen , Gao Wei , Salleh Muhamad Mat , Majlis Burhanuddin Yeop , Lee Jong Duk
Published: November 2010

The limited sensitivity of thinfilm based sensors has motivated the search for sensing structures and materials with greater sensing performance. Although thinfilm based SAW devices have been used as force, pressure, chemical and gas sensors so far. It is limited by the exposed sensing surface of the thinfilm. A feasibility study has been done by implementing the ZnO nanorods (NRs) to enhance the device sensitivity by greatly increase the exposed sensing surface. The implementation of these ZnO NRs as sensing elements is expected to enhance the sensing power due to the large surface to volume ratio. The sensing mechanism in this design is by detecting the minute change of seismic mass for ZnO NRs using surface acoustic wave before and after the attachment of reacting chemical liquid and gas substance.
First Principles Investigation of Geometrical and Electronic Structure of Semiconductor Fe1-XCoxSi2
Authors: Yan Wan Jun , Zhou Shi Yun , Gui Fang , Zhang Chun Hong , Guo Xiao Tian , Yang Yong
Published: November 2010

The electronic structure and optical properties of Fe1-xCoxSi2 have been studied using the first principle plane-wave pseudo-potential based on the density function theory. Substitutional doping is considered with Co concentrations of x=0.0625, 0.125, 0.1875 and 0.25, respectively. The calculated results show that the volume of β-FeSi2 increase and the band gap decrease with increasing of Co.
Microstructure and Electric Transport Characteristic of Microcrystalline Silicon Films Fabricated by Very High Frequency Plasma Enhanced Chemical Vapor Deposition
Authors: Wang Xiang , Huang Rui , Song Jie , Guo Yan Qing , Song Chao , Zhang Yi Xiong
Published: November 2010

Microcrystalline silicon (μc-Si:H) film deposited on silicon oxide in a very high frequency plasma enhanced chemical vapor deposition with highly H2 dilution of SiH4 has been investigated by Raman spectroscopy and high resolution transmission electron microscopy. Raman spectroscopy results show that the crystalline volume fraction increases with increasing the hydrogen flow rate and for the hydrogen flow rate of 160 sccm, the crystalline volume fraction reaches to 67.5%. Nearly parallel columnar structures with complex microstructure are found from cross-sectional transmission electron microscopy images of the film. The temperature depend dark conductivity and activation energy are studied in order to investigate the electronic transport processes in the nc-Si films.
Movement Realization of a Novel Fused Biconical Taper System Based on Electrical Heater
Authors: Shuai Ci Jun , Gao Cheng De , Nie Yi , Peng Shu Ping
Published: November 2010

A novel fused biconical taper system is developed based on electrical heating system. Its movement platforms are designed. The main drawing movement platform, heater movement platform and packaging movement platform are focused on analysis. Motion control program is developed based on Delphi 2006 according to its technological requirements. The experimental results show that the movement of the novel fused biconical taper system is very stable, and the optical fiber couplers fabricated with the novel system have the good optical performance and the good consistency in particular.
Physical Analysis of Electric Field Effect on Metal-Induced Crystallization of a-Si
Authors: Wang Guang Wei , Zheng Hong Xing , Yao Su Ying , Zhang Feng Shan
Published: November 2010

Amorphous silicon (a-Si) film crystallized by Ni-induced lateral crystallization under static electric field was analyzed. It has been demonstrated that Ni-induced lateral crystallization of a-Si is directional with electric field. Moreover, there exists a critical value of electric field strength, below which the rate of Ni-induced lateral crystallization of a-Si increases remarkably with the increase of field strength, while above which the rate will decrease instead. This phenomenon can be interpreted well based on electromigration effect.
Effect of Oxidant/Monomer Ratio on Conductivity of Ferric Chloride Oxidized Polypyrrole
Authors: Huang Yuan Ming , Zhai Bao Gai , Ma Qing Lan , Kong Xiao Yan
Published: November 2010

A series of polypyrrole samples were synthesized by oxidizing pyrrole in the aqueous medium of ferric chloride, and the relation between oxidant/monomer ratio and the electrical conductivity of polypyrrole was studied by increasing the ratio from 0.25:1 to 2.5:1. Our results showed that the conductivity of polypyrrole was dependent on the mole ratio of the oxidant to pyrrole, and a maximum value for electrical conductivity of 1500 S/m was achieved for a ratio of 0.75:1.
Effect of Surfactants on the Synthesis of Monodisperse Silica Spheres
Authors: Li Hong Liang , Li Ke Xun , Zhang Lin , Fu Ai Ping , Zhu Ying Chun , Wan Yong , Zhao Xiu Song
Published: November 2010

In this work, the influence of surfactant including the amount and the nature of the surfactant as well as alcohol solvents with different hydrocarbon chains including methanol, ethanol, 1-propanol and n-butanol on the formation of silica spheres were investigated. The morphologies and the composition of the prepared silica spheres were studied with scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) techniques. The results revealed that the size and size distribution of the spheres can be modified by changing the concentration or the nature of the surfactant additives. The influence mechanisms of surfactants additives and the alcohol solvent on the formation of silica spheres were discussed based on nucleation and growing process of the spheres.
Effect of Double Defects on Transmission Spectra of One-Dimensional Photonic Crystals
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai , Cai Yun Gao
Published: November 2010

Considered the model of the one-dimensional photonic crystals (1-D PCs) with double defects, the refractive indexes (n2’, n3’ and n2’’, n3’’) of the double defects were 2.0, 4.0 and 4.0, 2.0 respectively. With parameter n2=1.5, n3=2.5, by theoretical calculations with characteristic matrix method, the results shown that for a certain number (14 was taken) of layers of the 1-D PCs, when the double defects abutted, there was a defect band gap in the stop band gap, while when the double defects separated, there occurred two defect band gaps in the stop band gap; besides, with the separation of the two defects, the transmittance of the double defect band gaps decreased gradually. In addition, in this progress, the frequency range of the stop band gap has a little increase from 0.092 to 0.095.
Terminal Length Dependent Transmission Spectra for One-Dimensional Photonic Crystals with a Centered Defect
Authors: Huang Yuan Ming , Zhai Bao Gai , Cai Yun Gao , Ma Qing Lan
Published: November 2010

The model of the one-dimensional photonic crystals (1-D PCs) with a centered defect with increasing number of layers was considered, and characteristic matrix method was used to calculate the transmittance spectra of the 1-D PCs. From the transmittance spectra, it shown that during the course of the number N of the layers of 1-D PCs’ one side symmetrical increased from 2 to 16, there occurred defect band gap in the stop band gap, when N upped to 16 , the defect band gap disappeared; besides, the defect band gap is at the frequencies around 0.30. In addition, in the progress of N increased from 3 to 16, the defect band gap reduced from the frequency range 0.0570 to 0.00, and the transmittance declined from 73.59% to 13.94% in the defect band gap.
Effect of Sm Doping on Magnetic Properties of Sr2FeMoO6
Authors: Xu Zhen Feng , Liang Jun , Pei Juan , Yin Yan Yan , Li Chang
Published: November 2010

New electron doped double perovskite compound (Sr2-xSmx) FeMoO6 (0≤x≤0.25) has been synthesized by solid-state reaction. Crystal structure and magnetic properties of the compounds have been investigated by X-ray powder diffraction (XRD) and magnetic measurements. XRD revealed that all the compounds were of single phase and belonged to a I 4/m lattice. The degree of cationic ordering on the B site was decreased pronouncedly by the electron doping. Different from the results of La- and Nd-doped Sr2FeMoO6, Curie temperature (TC) of (Sr2-xSmx) FeMoO6 decreased first with the doping and then increased beyond x = 0.15, indicating that steric effect was enhanced as the radius of rare-earth ions decreased.
Laser Diffractions in Lyotropic Liquid Crystal Formed by Liquid Dishiwash
Authors: Huang Yuan Ming , Liu Wei Wei
Published: November 2010

We demonstrated that a lamellar phase of lyotropic liquid crystal formed by liquid dishwash could assemble themselves into crystal droplets when their isotropic phase was slowly changed into lamellar phase on the glass substrate. Characterization by means of polarized optical microscopy showed that a pattern of liquid crystal droplets was developed in the thin films formed by liquid dishwash. Our laser light diffraction experiments confirmed that these liquid crystal droplets could effectively diffract the incident red light from a helium-neon laser. On the basis of the Fraunhofer diffraction equation, we derived for the diameter of liquid crystal droplets. The diameter of liquid crystal droplet is 42.517 m, and almost agreement with the graph of polarized optical microscopy.
Fabrication of Small Triode-Type Cold-Cathode Field Emission Display with Staggered Gate-Electrode Layer
Authors: Li Yu Kui , Liu Yun Peng
Published: November 2010

Carbon nanotube used as cold cathode, the triode FED with staggered gate-electrode layer structure was fabricated with the screen-printing technique and conventional sintering process. Using superior mica plate as gate substrate material, the silver slurry was prepared to form the staggered gate electrode. The insulation layer was also manufactured over the gate substrate surface. The design and fabrication of the staggered gate-electrode layer was described in detail. By means of glass frit, the whole panel structure was vacuum-sealed. With the fabricated staggered gate-electrode layer, the modulation of electron emission from CNT field emitter by the gate voltage was confirmed. The packaged tridoe FED possessed better field emission uniformity, good image display performance and high display image brightness.
Transmittance of Polymer Dispersed Liquid Crystal Device
Authors: Ma Qing Lan , Huang Yuan Ming
Published: November 2010

Polymer dispersed liquid crystal (PDLC) devices were prepared by the method of polymerization induced phase separation. The transmittances and textures of the PDLC devices in OFF state and ON state were characterized by an ultraviolet-visible spectrometer and a polarized optical microscope, respectively. Our results demonstrated that the transmittances of our PDLC devices can be up to 95% when it is in ON state and that the transmittances of our PDLC devices is only about 20% when it is in OFF state.
High Precision Finishing Technique of Sapphire Substrate Surface for Photoconducting Device
Authors: Niu Xin Huan , Liu Xiao Yan , Wang Sheng Li , Tan Bai Mei
Published: November 2010

Sapphire (α-Al2O3) single crystal, as an important photoconducting device substrate material, stringent surface quality requirements, i.e. surface finish and flatness, are required. The use of chemical mechanical polishing (CMP) technique can produce high quality surface finishes at low cost and with fast material removal rates. The polishing mechanism was studied in this paper, and it was pointed that there were chemical and mechanical kinetics process respectively. The chosen polishing temperature was 40 oC. SiO2 sol was chosen as abrasive and the particle size is 40nm. The pH value was determined at 11.5~12. During CMP process C6382I-W/YJ single side polisher and SUBA 600 pad were used. After polishing and cleaning of sapphire surface, the measured removal rate was above 183.3nm /min and the surface roughness by using AFM was lower than Ra 0.3 nm. From the results, it was found that using such method, the optimal sapphire surface can be gotten, which is advantaged for epitaxial growth and device making-up.
Fabrication and Optimization of Printed Carbon Nanotube Field Emitters for Flat-Panel Display Device
Authors: Wu Chao , Li Ti Hong , Guo Ting Yue
Published: November 2010

Screen-printing process was adopted to prepare the carbon nanotube cathode. For improving the field emission performance of cold-cathode material, the optimized carbon nanotube cathode fabrication structure was given, and the detailed manufacture process was also described. The photoetched cathode indium-tin-oxide (ITO) stripes including the narrow bar ITO connecting line was fabricated to form the cathode electrodes. The annular silver conducting layer was adopted between the cathode ITO stripes and the carbon nanotube field emitters. The whole display device was packaged by means of glass frit, and vacuum-sealed through the exhaust tube. The fabricated field emission display could display some dot matrix number and characters, which possessed better field emission performance, higher display brightness and good field emission uniformity.
Dependence of the Morphology of Polymer Dispersed Liquid Crystal on Temperature
Authors: Ma Qing Lan , Huang Yuan Ming
Published: November 2010

Polymer dispersed liquid crystal film was prepared by the method of polymerization induced phase separation. The optical morphologies of the PDLC film were characterized by polarized optical microscope with a hot stage. Our results demonstrated that the morphology of the PDLC film depended on temperature of PDLC system.
Photoluminescence of Liquid Crystal Infiltrated Porous Silicon Film
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai
Published: November 2010

We have investigated the photoluminescence (PL) of a porous silicon film in which a typical nematic liquid crystal 4-pentyl-4’-cyanobiphenyl infiltrated. Before the liquid crystal filtration, the PL spectrum of the porous silicon film is comprised of two luminescent bands, one of which is located at about 600 nm whereas the other of which is located at about 450 nm. After the liquid crystal filtration, the porous silicon film gives off intense deep-blue PL with its peak located at about 400 nm at the cost of the complete quenching of the PL from the original porous silicon film. Our results have demonstrated that the luminescent properties of porous silicon films can be dramatically modified by liquid crystal infiltration.
The Effect of Donor:Acceptor Ratio on the Generated Photocurrent of Inkjet Printed Blended Poly (3-Octylthiophene-2.5-Diyl) and (6,6)-Phenyl C71 Butyric Acid Methyl Ester Bulk Heterojunction Organic Solar Cells
Authors: Fauzia Vivi , Umar Akrajas Ali , Salleh Muhamad Mat , Yahaya Muhammad
Published: November 2010

Bulk heterojunction organic solar cells made of blended of the electron donor (D) and electron acceptor (A) molecules were fabricated using inkjet printing technique with three different D:A ratios i.e. 1:3, 1:1 and 3:1 (weight). Poly (3-octylthiophene-2,5-diyl) (P3OT) and (6,6)-phenyl C71 butyric acid methyl ester (PC71BM) were used as donor and acceptor respectively. The generated photocurrents and the power conversion efficiency depend on the donor: acceptor ratio, where the device D:A ratio 3:1 generated higher photocurrent. The photovoltaic performance of the devices may also affected by the microstructure and surface morphology of the active layer film.
Synthesis of TiO2 Nanopowders and their Applications in Dye-Sensitized Solar Cell
Authors: Sun Jian , Wang Yan Xiang , Xu Min , Ma Ting Li , Fan Xue Yun
Published: November 2010

Dye-sensitized solar cells (DSSC) are currently attracting widespread interest for the conversion of sunlight into electricity because of their low cost and high efficiency. In these cells, photo-anode is one of the key components for high power conversion efficiencies. In this paper, TiO2 nanopowders were prepared by the non-hydrolytic sol-gel method using TiCl4 as precursor, absolute ethanol and isopropanol as oxygen donor. Several different TiO2 nanopowders were used to fabricate TiO2 solar cells, and properties of TiO2 solar cells were characterized. The solar cell prepared with grainsize 50~80nm TiO2 nanopowders generated a short-circuit photocurrent of 13.17 mA/cm2, an open-circuit photovoltage of 789 mV, a fill factor of 69.8% and the efficiency of 7.25% under the light intensity of 100 mW/cm2.
Performance Improvement of Inverted Polymer Solar Cells Using V2O5 as an Anode Buffer Layer
Authors: Shen Liang , Zhang Xin Dong , Guo Wen Bin , Liu Cai Xia , Wei Dong , Ruan Sheng Ping
Published: November 2010

In this paper, vanadium oxide (V2O5) was introduced between the active layer and top electrode as buffer layer. The structure of the photovoltaic device is ITO/TiO2/P3HT: PCBM/V2O5/Ag. TiO2, which was prepared in sol-gel method, was used as an electron selective layer. The performance of photovoltaic device with V2O5 layer is dramatically improved compared with that without V2O5. The power conversion efficiency is improved from 0.79% to 2.58% under 100 mWcm2 white light illumination in ambient air.
Growth and Optical Properties of ZnO Nanorod Arrays
Authors: Wei Lin , Zhang Guang Hua , Li Kang , Jiao Jun , Chen Yan Xue
Published: November 2010

ZnO nanorod arrays were prepared using a chemical solution route on fluorine-doped SnO2 conductive glass pre-coated by a thin ZnO seed layer. Morphology, crystal structure and growth direction of the nanorod arrays were characterized by SEM and XRD respectively. The SEM results demonstrated that ordered arrays of ZnO nanorods grew vertically on the substrate. XRD measurement revealed the ZnO nanorods were grown along the [002] direction of the ZnO crystallites. Under optimal condition, ZnO nanorods with the average length about 6-7 μm and the diameters about 10nm at the tip and 150 nm at the base were obtained. The optical properties of ZnO nanorod arrays were characterized by transmittance spectra and photoluminescence measurement at room temperature.
Optical Fiber Hydrogen Sensor Based on Magnetron Sputtered Pd/V2O5 Films
Authors: Zhou Ling De , Huang Jin Shan , Shi Yong , Wu Yin Wei , Yu Hai Hu
Published: November 2010

Laminated thin films composed of V2O5 and Pd (or Pt-Pd) layers were deposited on glass substrates and the end faces of multimode optical fibers, and the sensitive behaviors of the thin films to hydrogen gas were studied using a UV-visible spectrophotometer and an optical fiber sensor’s experimental setup. Both the thickness of the V2O5 layer and that of the Pd layer have obvious influences on the sensitivity performance of the Pd/V2O5 films. The Pd (30 nm)/V2O5 (280 nm) film deposited on a glass substrate is sensitive to 0.1% hydrogen and the highest change in relative transmittance is about 25% when exposed to 4% hydrogen. Pd/V2O5 films were coated onto the end faces of multimode fibers to form optical fiber sensors. The response time of the Pd (20 nm)/V2O5 (280 nm) sensor is about 50 s and the change in relative reflected light intensity is about 18% upon exposure to 4% hydrogen. Deposition of Pt-Pd double layer instead of Pd signal layer over V2O5 can reduce the response time of the sensor. The response time of the Pd (20 nm)/V2O5 (280 nm) sensor is about 50 s, while that of the Pt (10 nm)-Pd (10 nm)/V2O5 (280 nm) sensor is about 25 s.
New Cross-Coupling Control of Independent Linear Contour Errors Based on Backlash
Authors: Wang Sheng Bao , Liu Xiao Hong
Published: November 2010

On the basis of analysis of linear contour errors model, a new strategy of independent contour error control was presented for high precision contour machining. The proposed control scheme, in which the equations of the well-known cross-coupling controller were implemented, is shown to be able to diminish the linear contour error without using any cross-feeding signals between the driving axes. The simulation results show that the proposed control scheme is effective and that better effect of the contour tracking can be obtained. As a result, the contour machining precision is improved greatly.
A Simple and Novel Method for Large-Scale Preparation of Stable Copper Nanoparticles
Authors: Wen Yue Li , Huang Wei , Wang Bin
Published: November 2010

A simple and novel preparation method for Cu nanoparticles has been suggested in this work. Its main innovative thought lies in preparing nano-copper in liquid paraffin without addition of other reductant. The paraffin is cheap and nontoxic, and the copper nanoparticles prepared by this method are not oxidized when exposed to air at room temperature. The obtained nano-copper has been characterized by X-ray diffraction measurements (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive analysis of X-ray (EDX), X-ray photoelectron spectra (XPS), and Fourier transform infrared spectroscopy (FTIR). The TEM results confirm that the optimal average size of nanoparticles is about 20 nm. The effects of time, temperature and surfactant on the size of nano-copper have been investigated. The results show that the optimized conditions are reaction temperature of 250 oC and reaction time of 3 h. By this method, the raw materials are cheap and the process is simple, so it can be applicable to large-scale production of copper nanoparticles.