bluuebunny/crossref_metadata_2025 huggingface dataset:
Standard Errors of Equating Differences
Authors: Moses Tim , Zhang Wenmin
Published: June 2011

The purpose of this article was to extend the use of standard errors for equated score differences (SEEDs) to traditional equating functions. The SEEDs are described in terms of their original proposal for kernel equating functions and extended so that SEEDs for traditional linear and traditional equipercentile equating functions can be computed. These developments provide new understandings of the relationships between kernel and traditional equating functions that expand on prior developments of SEEDs and of standard errors of equating functions. The developments are demonstrated for an equivalent groups equating situation. The accuracies of the SEEDs are evaluated in simulations conducted using an equivalent groups equating example.
Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination
Authors: Jeon Hong Y. , Tian Lei F. , Zhu Heping
Published: June 2011

An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA).
High chemoselectivity in the phenol synthesis
Authors: Rudolph Matthias , McCreery Melissa Q , Frey Wolfgang , Hashmi A Stephen K
Published: June 2011

Efforts to trap early intermediates of the gold-catalyzed phenol synthesis failed. Neither inter- nor intramolecularly offered vinyl groups, ketones or alcohols were able to intercept the gold carbenoid species. This indicates that the competing steps of the gold-catalyzed phenol synthesis are much faster than the steps of the interception reaction. In the latter the barrier of activation is higher. At the same time this explains the high tolerance of this very efficient and general reaction towards functional groups.
Diffuse Retinal Pigment Epithelial Disease in an Adult with Cystic Fibrosis
Authors: Goren Jordana F. , Shah Sumit P. , Janzen Grant P. , Gross Nicole E. , Duker Jay S.
Published: June 2011

An adult with cystic fibrosis presented for decreased vision in the right eye of several months’ duration. Biomicroscopy and fluorescein angiography demonstrated bilateral large subretinal drusenoid deposits concentrated temporal to the fovea, as well as a small subretinal hemorrhage associated with focal leakage of fluid within the macula in the right eye. Optical coherence tomography demonstrated subretinal fluid consistent with choroidal neovascular membrane in the right eye with the absence of fluid in the left eye. The retinal manifestations of bilateral diffuse drusen associated with choroidal neovascular membrane may be consistent with autosomal dominant drusen, age-related macular degeneration, and type II glomerulonephritis, or alternatively may be a unique finding associated with cystic fibrosis. To the authors’ knowledge, these findings have not previously been described in association with cystic fibrosis.
Preparation and Characterization of Cu2ZnSnSe4 Thin Films by Selenization of Electrodeposited Metal Precursors
Authors: Li Ji , Zhang Zhong Wei , Ou Yang , Liu Wei Feng , Jiang Guo Shun , Zhu Chang Fei
Published: June 2011

Cu2ZnSnSe4thin films were prepared by selenization of electrodeposited Cu-Zn-Sn precursors. The Cu-Zn-Sn precursors were electrodeposited on the Mo-coated glass substrates from an electrolyte containing copper sulfate, zinc sulfate, tin (II) sulfate at a fixed potential between -1.2V and -1.25V vs. saturated calomel electrode, then the Cu2ZnSnSe4thin films were obtained by selenizing Cu-Zn-Sn precursors in elemental selenium atmosphere at different temperatures. The structure, composition and optical properties of the films were investigated by X-ray diffraction, Energy dispersive spectrometry and UV-VIS absorption spectroscopy. The CZTSe films have a stannite structure and an optical band-gap about 1.6 eV which is suitable for fabricating solar cells.
Properties of Fe Doped Amorphous Carbon Thin Films for Photovoltaic Solar Cell Applications
Authors: Tan Xin Yu , Zhang Xiao Zhong , Wan Cai Hua , Gao Xi Li
Published: June 2011

The iron-doped amorphous carbon films (a-C: Fe) and Al2O3 films were deposited on n-type silicon substrates using pulsed laser deposition to form (a-C: Fe)/Al2O3/Si solar cells in a pulsed laser deposition (PLD) system. The microstructure of the films was investigated by Raman scattering spectroscopy. The electrical properties of the films were characterized by room temperature electrical conductivity (σ) and the activation energy (Ea). The results show that the Fe-doped amorphous homogeneous structure is formed by Fe diffused into a-C films after annealing treatment. The a-C: Fe films are disordered graphitized carbon system and are rich in sp2. The (a-C: Fe) /Al2O3 /Si junction has good rectifying properties and remarkable Photovoltaic effect.
The Application of Simulation and Optimization in the Growth of High-Purity Silicon Thin Film on Low-Purity Silicon Substrate by Liquid Phase Epitaxial
Authors: Gao Yong Chao , Zhao Bai Tong , Gao Wen Xiu
Published: June 2011

This paper describe a method in the growth of high-purity Si thin film on low-purity silicon substrate by liquid phase epitaxial (LPE) growth, in order to eliminate the effect of melt substrate on the matrix, we simulate the matrix temperature effect on the epitaxial substrate temperature choice and the growth of thin film thickness with the growth time, then we carried out experiment according to the simulation result. Through the analyses experimental results, we found that on the low-purity silicon substrate can grow very good high-purity silicon thin film by liquid phase epitaxial (LPE) growth and thickness with growth time have little difference between the simulation. So we come to the conclusion: The growth of high-purity Si thin film on low-purity silicon substrate by liquid phase epitaxial (LPE) growth is a good way to make solar cell material; through the numerical simulation, we can effectively reduce the test energy consumption and test repeat times, which provide a good theoretical basis for the experiment successfully conduct.
The Effect of Target to Substrate Distance on the Properties of HAZO Films Deposited by Magnetron Sputtering
Authors: Lu Wei Ming , Zhang Jun , Diao Hong Wei , Zhao Lei , Wang Wen Jing
Published: June 2011

Hydrogen doped AZO films (HAZO) were prepared by RF magnetron sputtering. A systematic study of the effect of substrate to target distance (Dst) on the structural, electrical and optical properties of the as-grown HAZO films was carried out. Compared with the Al-doped ZnO films, the hydrogen in the atmosphere influenced the growth of the films by incorporating in the films and bombarding the surface of the film, namely, the Dst, which induced the residual stress and the roughness of the films decreasedwith an increase of the Dst. The films showed a smaller grain size. The surfacework function of the films changed with the composition of the films, reaching a maximum at 7.5cm.
Criteria for Evaluation for Eco-Material and the Case Study in Japan
Authors: Nara Matsunori
Published: June 2011

Criteria for evaluation for eco-material and the case study in Japan. An environmental performance of the material is described clearly from the viewpoint of international mutual agreement with the environmental label of ISO. The eco-material is evaluated with Law on Promoting Green Purchasing and the ISO environmental label, etc. in Japan. However, the doubt is caused in the validity of the united evaluation of all materials by the same functional processing module. However, enough inventory data doesn't exist to evaluate the material and the product under the present situation. Moreover, the difficulty of what the life time of the product uniformly defines is pointed out. Then, it is necessary to choose the proper procedure from social and a scientific viewpoint to make the criteria of the eco-material. The validity of the criteria is referred in the this study, and the note to make a fairer criteria is presented. The relation to the general person's recognition to the criteria and this was shown by using the method of Analytical Hierarchy Process(AHP). In addition, we introduce the evaluation scheme of the eco-material based on the LCA technique of the Ministry of Land, Infrastructure and Transport.
Effect of the Residual Template on Surface Photoelectric Characteristics of Structurally-Ordered Macroporous Nanocrystalline TiO2
Authors: Wei Sai Ling , Li Kui Ying , Yang Wei Yong , Wang Chun Mei , Zhang Jian
Published: June 2011

The Macroporous Nanocrystalline TiO2 Thin Film Was Prepared by Dipping-Coating Method. Polystyrene (PS) Microspheres Template Was Used as Pore-Forming Assistant and TiO2 Sol Was Used as Precursor. the Photoelectric Characteristics of the Samples Were Studied Using Surface Photovoltage (SPV) and Photoacoustic (PA) Techniques. the Presence of a Small Amount of Residual Template Damages the Integrity of the Porous TiO2 Film with Inverse Opal Structure, and TiO2 May Be Restricted in Certain Application Fields as Photonic Crystals. a Small Amount of Residual Template Changes the Surface Photovoltaic Properties of the Porous TiO2 Film, Resulting Mainly in the Broadened Scope and the Increased Intensity of SPV Response.
PILCs as Water-Transmitting Material and Application in Planting Trees in Drought Areas
Authors: Zhang Zeng Zhi , Wang Bo Tao , Zhou Shuang
Published: June 2011

Clay-based water-transmitting materials were proposed in order to solve the problems of dry soil layer and watering during forest planting in drought areas. The pillared interlayered clay was prepared in the presence of primary bentonite. The conductivity property was investigated under various conditions of cross-linking agent ratio. The structural aspects and thermal degradation of composites were also studied by means of XRD, TG and porosity analysis. The results indicated that pillared clays modified by Al cross-linking agent exhibit higher water conductivity properties remarkably. Larger specific surface area, more pores and complicated pore structures play vital roles in the enhancement of the conductivity property. This kind of material can obviously elevate capillary water upward from subsurface aquifer to the roots of saplings in drought areas so as to improve the survival rate of the saplings.
Effect of Small Amount of Zn Additions on the Magnetocaloric Properties of Gd5Si2Ge2 Alloy
Authors: Wang Xue Zhen , Xiang Jie , Zeng Zhi , Hu Xing Hao , Hou Xue Ling , Xu Hui
Published: June 2011

The structural and magnetic property of Gd5Si1.99Ge2Zn0.01and Gd5Si2Ge2alloys prepared by arc-melting the starting materials with commercial available purity (99.95wt%) was investigated by x-ray diffraction and Vibrating Sample Magnetometer. The result shows that the Gd5Si1.99Ge2Zn0.01alloy has monoclinic phase with Gd5Si2Ge2-type structure. The polymorphic orthorhombic phase with Gd5Si4-type structure coexists with the monoclinic phase in Gd5Si2Ge2alloy. The addition of small Zn element in Gd5Si2Ge2alloy results in a considerable enhancement of its magnetocaloric effect. The maximum magnetic entropy change rapidly increases from 5.03J/(kg K) to 20.70J/(kg K) for a magnetic field change from 0 to 1.5T. The magnetic order temperature is 278K in Gd5Si1.99Ge2Zn0.01alloy and 278.5K in Gd5Si2Ge2alloy respectively. The magnetocaloric effect of Gd5Si2Ge2with the small addition of Zn is significantly improved.
Mechanism of High Fracture Strength of Bone
Authors: Chen Bin , Yin Da Gang , Yuan Quan , Luo Ji , Fan Jing Hong
Published: June 2011

Scanning electron microscope (SEM) observation showed that femur bone is a kind of bioceramic composite consisting of hydroxyapatite layers and protein matters. The hydroxyapatite layers are further composed of hydroxyapatite fiber sheets. The observation also showed that the hydroxyapatite fiber sheets possess very thin fiber shape. The thickness of the hydroxyapatite fiber sheets is within nanometer scale. The mechanism of the high fracture strength of the bone was investigated based on the microstructural characteristics of the hydroxyapatite fiber sheets and the theory of fracture mechanics. The result reveals that the thin fiber shape of the hydroxyapatite fiber sheets endows the bone with high fracture strength.
Gelation of Ionic Liquid-Based Electrolyte with Ordered Mesoporous Silica Particles for Quasi-Solid-State Dye-Sensitized Solar Cells
Authors: Wang Gui Qiang , Wang Liang , Xing Wei , Zhuo Shu Ping
Published: June 2011

Ordered Mesoporous Silica with Uniform Pore Size Was Prepared by Using Pluronic P123 as the Structure-Directing Agent. their Characteristics Were Analysized by TEM and a N2Adsorption System. Ionic Liquid-Based Gel Electrolyte Was Fabricated by Using Ordered Mesoporous Silica as the Framework Materials to Solidify Ionic Liquid Electrolyte. the Diffusion Coefficient of I3-in Gel Electrolyte Is Higher than that in Ionic Liquid Electrolyte due to the Formation of Favorable Channel for I3-Diffusion. the Optimized Overall Conversion Efficiency of Dye-Sensitized Solar Cells with Ionic Liquid-Based Gel Electrolyte Was 5.22% under Irradiation of 60 MW Cm-2.
Aluminum-Doped Zinc Oxide as Transparent Electrode Materials
Authors: Zhang Yu Long , Zhang Xian Peng , Tan Rui Qin , Yang Ye , Zhao Jun Hua , Wang Wei Yan , Cui Ping , Song Wei Jie
Published: June 2011

Pristine and Al-doped zinc oxide nanopowders were synthesized via a surfactant-assisted complex sol-gel method, possessing a pure ZnO phase structure and controllable grain size which was characterized by X-ray diffraction and scanning electron microscopy. Using these nanopowders, the pristine and Al-doped ZnO magnetron sputtering targets were prepared following a mold-press, cold isostatical-press and schedule sintering temperature procedure. The relative density of these as-prepared targets was tested by Archimedes’ method on densitometer. All of the results were above 95 theory density percents, and the resistivity was tested on four-probe system at a magnitude of 10-2Ω cm. Related pristine ZnO thin films and Al-doped ZnO thin films were fabricated by magnetron sputtering method, respectively. The pristine and Al-doped ZnO films deposited on the quartz glass by dc sputtering owned a (002) orientation with a thickness of 350 nm at a deposition power of 100 W for two hours under an argon plasma. A good optical transparency above 80% and low resistivity of 1.60×10-3Ω cm were obtained with a deposition temperature of 573 K. The optical energy bandgap could be tailored by Al doping at 4 at.% Al.
Graded Buffer Layer Effect on Performance of the Amorphous Silicon Thin Film Solar Cells
Authors: Lien Shui Yang , Yang Meng Jia , Lin Yang Shih , Chen Chia Fu , Lin Po Hung , Hsu Chia Hsun , Huang Po Ching , Shen Yu Ming
Published: June 2011

It is widely accepted that graded buffer layer between the p-layer and i-layer increase the efficiency of amorphous silicon solar cells. The open-circuit voltage (Voc), short current density (Jsc) and fill factor (FF) of the thin film solar cell are obviously increased. In the present study, hydrogenated amorphous silicon (a-Si:H) thin film solar cells have been fabricated by 27.12 MHz plasma enhanced chemical vapor deposition (PECVD). We discussed the three conditions at the p/i interface without buffer layer, buffer layer and graded buffer layer of thin film solar cells by TCAD software. The influences of the performance of the solar cell with the different buffer layer are investigated. The cell with graded buffer layer has higher efficiency compared with the cells without buffer layer and buffer layer. The graded buffer layer enhances the conversion efficiency of the solar cell by improving Vocand FF. It could be attributed to a reduction of interface recombination rate near the junction. The best performance of conversion efficiency (η)=8.57% (Voc=0.81 V, Jsc=15.46 mA/cm2, FF=68%) of the amorphous silicon thin film solar cell was achieved.
Hydrothermal Growth of ZnO Nanowires on Patterned Seed Layer
Authors: Zhao W.G. , Zhang Q. , Ma Zhong Quan
Published: June 2011

Using a novel approach with low-cost and simple-equipment, the hydrothermal growth of ZnO nanowires array films on glass substrates was carried out after pre-coated ZnO nanoparticle precursor as crystalline nuclei. The physical phase and morphology of the ZnO thin films with nanowires structure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results indicate that ZnO films with nanowires array are hexagonal symmetry and highly oriented crystalline array films, which grows along c-axis of ZnO. The diameter of the nanowires is about 60 nm. A strong UV peak, a weak blue band and a weak green band at 399, 469 and 569 nm is observed, respectively, in the photoluminescence (PL) spectra.
Light Trapping in Dye Sensitized Solar Cells with Length-Modulated TiO2 Nanotubes
Authors: Shen Cheng , Shen Ling , Yang Jie , Shi Jian Wei , Xu Fei , Ma Zhong Quan
Published: June 2011

Highly Oriented TiO2Nanotube (NT) Arrays Were Fabricated by Anodizing Ti Foils. the Morphology of the NT Arrays Was Characterized by Scanning Electron Microscope. by Adjusting the Anodization Time, the Lengths and Diameters of TiO2NT Arrays Changed from 6.7 to 19.5 μm, and 90 to 110 Nm, Respectively. as Confirmed by X-Ray Diffraction and Raman Spectra, the as-Anodized TiO2NTs Were Amorphous but Transformed into Anatase Phase after Annealing at 450°C for 3 H. Reflectance Spectrum of TiO2NT Arrays Showed that NT Layer of Longer Length Lowered the Reflectance in the Visible Spectrum because of Light Trapping Effects of NTs, Thus Enhancing Light Harvesting of NTs. Dye-Sensitized Solar Cells Were Fabricated Using TiO2NT Arrays with Different Tube-Lengths. Analysis of Photocurrent Density-Voltage (J-V) Characteristics Showed that Higher Photoconversion Efficiencies Were Achieved with Longer NT Lengths.
Influence of Nano-SiO2 on the Strength of High Performance Concrete
Authors: Wang Bao Min
Published: June 2011

The influence of Nano-SiO2 (NS) on the strength of high-performance concrete (W/B=0.24, W/B=0.29, W/B=0.34) has been studied in this paper. The results show that compressive strengths of concrete in both the early and later stage can be improved by adding Nano-SiO2 content. And the influence on the early compressive strength is greater than that on the later compressive strength. According to the results, 3%-5% Nano-SiO2can be used as the proper mixing ratio. X-ray diffraction, SEM (scanning electron microscope) and mercury injection experiment were used to analyze the action principle of Nano-SiO2 microscopically, the microscopic characteristics of concrete can be significantly improved through interfacial and filling effect effects so that the performance of concrete can be accordingly improved.
Preparation and Characterization of Carbon Fibre Reinforced Aluminium Matrix Composite
Authors: Sui Xiao Ming , Xu Xi Liang , Zheng Xiao Meng , Xu Guang Zhi , Wang Qiang
Published: June 2011

Driven by the increasing requirements from aircraft producers, aluminium alloy matrix composites with carbon fiber reinforcement have been largely used in the modern industry. The method of traditional preparation of carbon fiber reinforced aluminum matrix composites is not only high cost and complex to produce but also difficult to apply in the civilian. The present paper focuses on exploratory study on the preparation of carbon-fiber- reinforced aluminum composites, the intensifying material is continuous long carbon fiber. In order to avoid any interfacial reactions in the carbon fiber reinforced composites, the carbon fibers were coated with copper. We made The tensile samples were made by using the mould, the tensile properties determined, the strengthening mechanism studied, and the carbon fiber in the matrix observed with the microscope.
Magnetic Properties of Highly Permeable MnZn Ferrites with Addition of Phosphorous Pentoxide
Authors: Su Hua , Zhang Huai Wu , Tang Xiao Li , Liu Bao Yuan
Published: June 2011

The effects of phosphorous pentoxide on the properties of highly permeable MnZn ferrites have been investigated in this study. It was found that P2O5 addition had a pronounced effect on promoting crystalline grain growth. At the same time, porosity had an initial decrease followed by a subsequent increase with the increase of P2O5 content. Consequently, the initial permeability first increased, and then gradually decreased. Magnetic loss of the samples was also influenced by both grain size and porosity. With 0.06wt% P2O5 addition, the initial permeability reached to the maximum and the magnetic loss declined to the least. Porosity was the dominating factor to determine the ηB (hysteresis material constant) property of the ferrites. With 0.04wt% P2O5 addition, porosity decreased to its bottom, accordingly, the ηB value decreased to the least. Synthetically considering high initial permeability, low ηB value and good permeability frequency characteristic, the content of P2O5 addition had better be kept at 0.04wt%.
(1-x)(K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xBiFeO3 Lead-Free Piezoelectric Ceramics with CuO Sintering Aid
Authors: Zhao Yong Jie , Zhao Yu Zhen , Huang Rong Xia , Liu Rong Zheng , Zhou He Ping
Published: June 2011

(1-x) (K0.475Na0.475Li0.05)(Nb0.975Sb0.025)O3-xmolBiFeO3 (x=0, 0.002, 0.004, 0.006, 0.008) doped with 0.8mol%CuO lead-free piezoelectric ceramics were prepared by the solid state reaction technique. X-ray diffraction patterns suggested that all the ceramics presented perovskite structure. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. The ceramic (x=0.002) near room temperature exhibited excellent electrical properties (piezoelectric constant d33=172pC/N, planar electromechanical coupling factor kp=0.43, and dielectric constant =418). A relatively high mechanical quality factor (Qm=200) was also obtained in this particular composition. All these results revealed that this system might become a promising candidate for lead-free piezoelectric materials.
In Situ X-Ray Reflectivity Study of Imprint in Ferroelectric Thin Films
Authors: Cao Jiang Li , Zhang Kai , Solbach Axel , Yue Zhen Xing , Wang Huang Hua , Chen Yu , Klemradt Uwe
Published: June 2011

The structural origin of imprint in Pb(Zr,Ti)O3 (PZT) ferroelectric thin films derived by chemical solution deposition with Pt top and bottom electrodes was studied by in-situ high-resolution X-ray specular reflectivity of synchrotron radiation. Global structural parameters of density, thickness, and surface or interface roughness of each component layer in the thin film sample were obtained. No generation of interfacial layers with a different electron density from PZT and no interface roughening were observed at the interfaces of PZT and Pt during imprint. Thus, the results suggest that the imprint effect is more likely a bulk or electronic defects-related phenomenon.
Insulation Treatment of 2A12 Aluminum Alloy Surface by Plasma Electrochemical Oxidation
Authors: Liu Ming , Sun Zhi Hua , Wang Zhi Shen , Zhang Xiao Yun , Lu Feng
Published: June 2011

The 2A12 aluminum alloy surface is treated by plasma electrochemical oxidation (PEO) in alkaline solution. X-ray Diffraction (XRD) is used to analyze the phases of PEO coatings. Scanning Electron Micrograph (SEM) is used to investigate the compactness of PEO coatings. High resistance meter and voltage resistance meter are used to measured Electric resistance and breakdown field strength of PEO coatings respectively. The results show that the PEO coating is composed of α-Al2O3, γ-Al2O3 , etc, and they are all well-insulated substance which is profitable to insulation of 2A12 aluminum alloy. When the thickness of PEO is more than 60μm, porosity in the PEO coating is estimated not more than 15%. Electric resistivity of PEO coatings can reach as high as 1013 Ω·cm, and breakdown field strength of the PEO coatings can reach 72 V / μm.
Microstructure and Dielectric Properties of Ba0.6Sr0.4TiO3 Ceramics Co-Doped Al2O3-MgO
Authors: Hu Guo Xin , Gao Feng , Cao Xiao , Liu Liang Liang
Published: June 2011

The Ba0.6Sr0.4TiO3 (BSTO) ceramics were prepared by a traditional electrical ceramic method. Effects of co-doping low dielectric constant oxides Al2O3and MgO on microstructure and dielectric properties of Ba0.6Sr0.4TiO3ceramics were investigated. The results show that BSTO/MgO/Al2O3(BMA) ceramics can be sintered at 1300°C. The main crystal phases are cubic perovskite structure Ba0.6Sr0.4TiO3and face-centered-cubic spinel structure MgAl2O4. Al3+is easier to enter Ba0.6Sr0.4TiO3lattice in the replacement of Ti4+than Mg2+. When Al2O3content exceeds 20wt%, Al2O3would react with BaAl2O4to generate a new phase of BaAl12O19. Proper amount of Al2O3-MgO can reduce the dielectric constant of BSTO ceramics and result in the higher tunability. There is obvious frequency dispersion characteristic in BMA ceramics and the curie temperature of ceramics decreases with the increase of Al2O3. The BMA ceramics with 20 wt% Al2O3exhibit good dielectric properties, with εrof 1314, tanδ of 0.003 at 10 kHz, and the dielectric constant tunability of 35.2% under a dc electric field of 1.0 kV/mm, which are useful for potential tunable device applications.
Preparation and Relaxor Behavior of Barium Strontium Titanate Glass-Ceramics Doped Si-B-O Sintered from Sol-Gel Derived Powders
Authors: Wang Jiang Ying , Zhang Jing Ji
Published: June 2011

The structural and dielectric properties of Si-B-O doped Ba0.60Sr0.40TiO3(BST) glass-ceramics prepared by using sol-gel derived powders have been investigated. The secondary phase of BaTi2Si2O8is clearly observable in BST glass-ceramics when the concentration of Si-B-O is equal to or more than 20mol%. The samples with high Si-B-O doping levels can be sintered into dense microstructure in low sintering temperature (below 1000°C). The dielectric peaks of BST glass-ceramics are markedly suppressed, broadened and shifted to low temperature with increasing the concentration of Si-B-O, accompanying an increased diffuseness of the dielectric peak due to the ionic substitution, which follows well the Lorenz-type relation.
Effect of RE on Creep Rupture Life of SnAgCu Solder Joints
Authors: Wang Yao Li , Dong Gai Hong , Li Chen Yang , Wu Zhi Wei , Sun Jing
Published: June 2011

Creep property is one of the most important factors to affect the reliability of soldered joints. The effect of rare earth(RE) on the creep rupture life of Sn2.5Ag0.7Cu solder joints were investigated under constant temperature and stress using creep specimens with a 1mm2cross sectional area. The results show that adding tiny RE in Sn2.5Ag0.7Cu solder alloy can effectually affect the size and configuration of the intermetallic compound (IMC) of interfacial layer. The IMC of Sn2.5Ag0.7Cu interfacial layer is thinner and its thickness is homogeneous with adding 0.1% RE, and the creep rupture life of solder joints is longest, which is apparently superior to that of Sn2.5Ag0.7Cu and commercial used Sn3.8Ag0.7Cu solder alloy.
Study on Properties of High Power and Receiving-Projecting Dual-Purpose Piezoelectric Ceramic
Authors: Ju Chao , Xu Dong Yu , Zhang Zong Zhen , Huang Shi Feng
Published: June 2011

The piezoelectric ceramics Pb0.94Sr0.06(Zr0.53Ti0.47)O3+(Ni2O3+Cr2O3)0.1wt% + x wt%MnO2 + y wt%CeO2 (abbreviated as PCrNi-4) were prepared by a traditional ceramics process in this paper. The influences of MnO2 and CeO2-doping and sintered temperature on matrix material properties were studied by orthogonal tests. The effects of different inducing factors on the microstructure and dielectric loss were analyzed by means of XRD, SEM and electric measurement. The results indicate that the optimum process conditions are w(MnO2)= 0.1%, w(CeO2)= 0.3% and the sintering temperature 1280°C. The property parameters of samples are: d33=304.8pC/N, Kp=0.6113, εT33=1520, tanδ=0.00289, d33×g33=61.12×10-12CVm/N.
The Dielectric Characteristics of Sr and Mg Doped CCTO Ceramics
Authors: Liu Qiu Xiang , Tang Xin Gui , Jiang Yan Ping , Dong F. L.
Published: June 2011

Two kinds ceramics of pure CaCu3Ti4O12 (CCTO) and Sr/Mg doped (Ca0.25Cu0.75)0.5Sr0.5TiO3 + xMgO (x=0.01, 0.03, 0.05, 0.1, denoted as CCST-M-1, CCST-M-3, CCST-M-5, CCST-M-10, respectively) were prepared using the traditional solid phase reaction method. The dielectric properties were measured by HP 4194A Impedance/Gain-Phase Analyzer with the frequency range from 100 Hz to 1MHz. The temperature dependence of dielectric constant and loss tangent were measured for different frequencies. The variation relation of the critical temperature with the frequency was fitted theoretically which is in agreement with the Arrhenius law for pure CCTO. According to a variable power law to describe the paraelectric dielectric constant of ferroelectrics with diffuse phase transitions, the theoretical fitting was carried out for doped samples, and it was suggested that all doped samples exhibited the Debye-like relaxation. Among the doped and pure CCTO samples, CCST-M-1 was of the lowest dielectric loss at the whole measurement frequency, and whose I–V response curve was nonlinear suggesting a non-ohmic contact. The complex-impedance analysis results showed that the reduction in dielectric loss of CCST-M-1 sample can be attributed to the increase of grain boundary resistance. It is expect that these results are helpful to promote the CCTO-related materials to practical applications.
The Effect of Ca or Ba Substitution on the Properties in Bi0.87La0.05B0.08FeO3 (B＝Ca, Ba) Ceramics
Authors: Jiang Qing Hui , Zhao Shu Jin , Qi Yong Xin , Yang Ping
Published: June 2011

Multiferroic Bi0.87La0.05B0.08FeO3 (B＝Ca2＋, Ba2＋) ceramics were prepared by sol-gel method and spark plasma sintering with the protection of CeO2 powders. The substitution of Ba increases the samples’ magnetic properties, which leads to higher leakage current and makes the bulk ceramics high dielectric loss (0.1-0.2). In contrast, Bi0.87La0.05Ca0.08FeO3 ceramics have high breakdown field strength (220 kV/cm) and low loss (tand~2%), and the dielectric constant is stable (about 100) in the frequency between 102 and 106 Hz. Meanwhile, Ca doping improves the ceramic coercive field and ferroelectric domains do not switch under 220 kV/cm, leading to slim ferroelectric loops.
The Nd-Doping Effect on Dielectric Abnormity of BiFeO3 Ceramics below the Néel Temperature
Authors: Chen Dong Ge , Tang Xin Gui , Liu Qiu Xiang , Cheng Xiao Fang , Zou Yan
Published: June 2011

Bismuth neodymium ferrite (Bi1-xNdxFeO3: BNFO;x=0, 0.025, 0.075, 0.125, 0.175) ceramics were prepared by a co-precipitation method and sintered at 800 °C, using nitrates as precursors. The crystal structure and dielectric properties of the samples were characterized by X-ray diffraction （XRD）and dielectric permittivity measurement at different temperatures and frequencies. XRD suggests that the impurity phases are weakened by suitably dopingx=0.075. Dielectric spectra indicate that relaxation peaks below the Néel temperature which may be produced by the effect of grain boundaries and dipoles with heating vanish after doping Nd at the same content. Complex impedance spectra manifest that the doped samples are closer to Debye-type, and the impedance rises which will lead to low leakage current.
Deformation Behavior of Polycrystalline Fe-Ga-B Alloy at Elevated Temperature
Authors: Li Ji Heng , Gao Xue Xu , Zhu Jie , Bao Xiaoqian , Zhang Mao Cai
Published: June 2011

In this work, the hot deformation behavior of Fe83Ga17alloy with 1.0 at.% B addition was investigated by plane strain compression tests on a Gleeble-1500 hot simulation test machine in the deformation temperature range of 350 to 900 °C. The effects of strain rate range 0.1-10 s-1on flow stress and microstructure were also studied. It was indicated that as the temperature increases, significant softening of the material occurred, and significant dynamic recovery at low strain rate (0.1 s-1) and recrystallization at high strain rate (10 s-1) occurred during deformation at 900 °C. The results also suggested that deformation mechanism under low temperature (~500°C) was twinning. The hot deformation activation energy (Q) of the Fe83Ga17with 1.0 at.%B alloy was calculated to be 295.3 kJ/mol.
Martensitic Transformation and Mechanical Properties of Fe-Doped Ni54Mn21Ga25 Alloys
Authors: Xue S. X. , Feng S.S. , Cai P. Y. , Li Q T , Wang H. B.
Published: June 2011

Ni54Mn21-xFexGa25（x=0,1,3,5,7,9）polycrystalline alloys were prepared by the technique of directional solidification and the effect of substituting Fe for Mn on the martensitic transformation and mechanical properties of the alloys was analyzed. It was found that the Curie temperature increased with increasing substitution while the martensitic transformation temperature decreased. The Fe-doped Ni54Mn21Ga25 alloys exhibit excellent magnetic properties at room temperature; the typical Ni54Mn20Fe1Ga25 alloy shows a large magnetic-induced-strain of -1040 ppm at a magnetic field of 4000 Oe.
The Overlooked Hydrogen Effect in Ti-Ni-Based Shape Memory Alloys
Authors: Fan Gen Lian , Li Zhi Qiang , Zhang Di , Ren Xiao Bing
Published: June 2011

Having the smallest atomic radius, hydrogen can easily enter into many metals either by intentional doping or by inadvertent exposure to humid air. For Ti-Ni-based shape memory alloys, our recent studies have shown a specific effect of hydrogen in this important class of alloys, i.e., the interaction between hydrogen and twin boundaries can result in a very high damping peak in the martensitic state; thus hydrogen can be utilized to develop high damping materials. In the present study, aiming to provide a more comprehensive investigation to the role of hydrogen in Ti-Ni-based shape memory alloys, we systematically studied the hydrogen effect on martensitic transformation behavior, and twinning stress. By comparing the results from two sets of samples, one with and another without hydrogen, we obtained the following results. Firstly, hydrogen can lower the martensitic transformation temperature and reduce the transformation heat. Secondly, the twinning stress increases with hydrogen doping, and a typical yielding was found in the tensile testing for the sample containing hydrogen, which is absent in the H-free sample. This indicates that the hydrogen-twin boundary interaction also affect dc mechanical properties.
The Performance of Silicone Coatings Filled with Modification Carbon Nanotubes
Authors: Qiu Wu Gao , Zhang Zhan Ping , Qi Yu Hong , Zhang Peng Chao
Published: June 2011

Silicones coatings were widely used owing to their excellent low surface energy and good flexibility. The structure of the modified multiple wall nanotubes (MWNTs) was tested by IR. Influence of content and sort of MWNTs on microstructures, hydrophobicity of coatings and EIS was investigated using SEM, contact angle measurement (CAM) and electrochemical workstation. The results show that various groups had embedded carbon nanotubes, the coating modified by MWNTs has much lower surface energy than that of the coating wothout modification, the coating modified by different MWNTs have diverse surface energy, and the low-frequency impedance of the coatings was not decreased as the weight of MWNTs increased.
60Co Gamma–Ray Irradiation Effects on Pentacene-Based Organic Thin-Film Transistors
Authors: Cai Li , Hirao Toshio , Yano Hiroaki , Duan Zong Fan , Takayanagi Hideharu , Ueki Hideharu , Ohshima Takeshi , Nishioka Yasushiro
Published: June 2011

Electrical characterization of 60Co γ-ray radiation effects on pentacene-based organic thin-film-transistors having two kinds of gate insulator have been carried out. For transistors with SiO2 gate insulator, the threshold voltage shifts are consistent with positive charge trapping in the oxide and a “rebound” effect is observed. This “rebound” effect is attributed to the negatively charged interface traps generated during irradiation. For polyimide gate insulator, the threshold voltage continually decreases with an increasing total-dose. At total-dose of 1200 Gy (Si), for the SiO2 gate insulator, the field-effect mobility decreased by almost 80%, and for polyimide gate insulator, it decreased by 40%.
Combinatorial Synthesis and Evaluation on Thermoelectric Films
Authors: Wang Qun Jiao , Xu Min
Published: June 2011

Combinatorial technology is a powerful tool for new material exploration. Some new combinatorial technologies, such as combinatorial laser molecular beam epitaxy (CLMBE) and combinatorial pulsed laser deposition (CPLD), were introduced in the paper. La1-xCexVO3 (0≤x≤1) composition-spread films were fabricated successfully by CPLD, while their thermoelectric properties and structures were evaluated by the multi-channel thermoelectric measurement system and concurrent X-ray analysis respectively. Combinatorial technologies are proving to be an efficient, low-cost tool in synthesis and characterization of thermoelectric composition-spread films.
Corrosion and Wear Behavior of Nitrogen-Doped TiO2 Coatings on Stainless Steel Prepared by Plasma Surface Alloying Technique
Authors: Wang He Feng , Tang Bin , Li Xiu Yan , Ma Yong , Yang Chen Quan
Published: June 2011

A novel process has been developed to improve tribological and corrosion properties of austenitic stainless steel (S. S). Titanium nitride coatings were obtained by plasma surface alloying technique. Nitrogen-doped titanium dioxide was synthesized by oxidative annealing the resulted TiNx coatings in air. The microstructure of TiO2coatings was characterized by SEM, GDOES, XPS and XRD, respectively. Simulated body solution (Hanks’ solution, 37°C) was used to characterize the electrochemical corrosion properties of the coatings and substrate. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate against Al2O3ball. Results reveal that the resultant coatings have a layered structure, comprising of N-doped TiO2layer at the top and a diffuse-type interface. Such a hybrid coatings system shows good adhesion with the substrate. Composition analysis shows that the coatings shield the substrate entirely. The N-doped TiO2coatings are anatase in structure as characterized by X-ray diffraction. The electrochemical measurements show that the corrosion potential positively shifts from -0.267 V for bare S. S to -0.275 V for N-doped TiO2coated S. S, and the corrosion current density decreases from 1.3 × 10-5A/cm2to 4.1 ×10-6A/cm2. Under a load of 7.6 N, the coefficient of friction is in the range of 0.27～0.38 for the N-doped TiO2and the wear rate of the coatings is only one-fourteenth of that for untreated 316L S. S. Duplex-treated N-doped TiO2coatings display much better wear resistance and antifriction performance than that of S. S.
Effects of the CNT on the Preparation and Electrochemical Performances of the CNT / PANI Hollow Sphere Composite
Authors: Jiang Qi , Xie De Yu , Fu Guang Gang , Huang Bin , Zhao Xiao Feng , Zhao Yong
Published: June 2011

In this paper, a hollow sphere carbon nanotube (CNT) / polyaniline (PANI) composite was prepared by using the Fe3O4as a template. At the same time, the pure PANI and CNT/PANI composite were obtained with same method without Fe3O4template. The composition and the morphology of the obtained samples were characterized by the Fourier transform infrared spectroscopy and scanning electron microscope. And the electrochemical performances of the obtained materials were tested by the cyclic voltammogram, galvanostatic charging/discharging and cycle life testing. The results show that the obtained hollow sphere CNT/PANI composite have larger surface area than pure PANI and CNT/PANI composite for its hollow sphere structure. The obtained hollow sphere CNT/PANI composite have 185 F/g specific capacitance (in organic electrolyte), which is much more than those of the pure PANI and CNT/PANI composite (about 65 F/g, 152 F/g). The results also show that CNT have a great effect on the preparation of the hollow sphere CNT/PANI composite.
Influences of Nitrogen Partial Flux on the Phase Structures and Electrical Properties of Aluminium Doping TaNX Thin Films
Authors: Jiang Hong Chuan , Si X. , Zhang Wan Li , Peng Bin , Wang C. J.
Published: June 2011

Aluminium doping TaNx thin films were deposited on Al2O3 ceramic wafers by DC reactive magnetron sputtering. The influences of nitrogen partial flux on the phase structures and the electrical properties of the samples were investigated in detail. The results show that the main phases in the samples are gradually changed from poor nitrogen phases to rich nitrogen phases with the increase of the nitrogen partial flux. The deposition rate of the samples is decreased with the increase of the nitrogen partial flux. With the increase of the nitrogen partial flux, the resistivity and the absolute value of the temperature coefficient of resistance (TCR) of the samples increase slowly at lower nitrogen partial flux, and then increase remarkably at higher nitrogen partial flux. These experimental results can be explained by the presentation of rich nitrogen phases with higher resistivity and absolute value of the TCR when the samples were prepared at higher nitrogen partial flux.
Microstructure and Corrosion Resistance of Aluminized Coatings on Magnesium Alloy by Pulsed Bias Magnetron Sputtering
Authors: Tian Lin Hai , Zhu Rui Hua , Zhang Yan , Tang Bin
Published: June 2011

Aluminized coatings were prepared on AZ91D magnesium alloy using pulsed bias magnetron sputtering. Effects of deposition temperature on the microstructure and corrosion resistance were studied. The microstructure, element distribution and hardness of the coatings were characterized using optical microscopy (OM), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDOES), and microhardness tester, respectively. The corrosion behavior of the aluminized coatings was studied by measuring anodic polarization curves in 0.5 wt% NaCl solution and compared with that of bare AZ91D. Results show that the aluminized coatings are composed of a deposition layer and a diffusion layer. With deposition temperature increasing, the thickness of deposition layer decreases while diffusion layer thickness increases. The interdiffusion of Al element with other elements in AZ91D magnesium alloy substrate results in a metallurgical bonding of the coatings with substrate. The coatings are mainly composed of γ-Al and α-Mg phase. A small amount of β-Al12Mg17 phase appears at higher temperature of 450°C. The surface microhardness of magnesium alloy is obviously improved by the aluminized coatings. The hardness gradually decreases along the depth of aluminized coatings and the hardness gradient becomes smooth with the increasing of deposition temperature. The corrosion resistance of magnesium alloy is increased considerably by the aluminized coatings with more positive corrosion potential and an order of magnitude decrease of the corrosion rate than the bare magnesium alloy.
Microstructure and Magnetic Properties of FePt/Ag Nanocomposite Films with Perpendicular Orientation
Authors: Li Bao He , Feng Chun , Chen Xiao Bai , Ju Hai Lang , Zhao Jia , Geng Ai Cong , Xu Deng Hui , Li Xiong
Published: June 2011

[FePt(2 nm)/Ag(d nm)]10 mutilayers were deposited on single crystal MgO (100) substrates by magnetron sputtering. L10-FePt/Ag nanocomposite films with a high coercivity and a perpendicular orientation were achieved by annealing the as-deposited films at 600 °C for 15 min. The result of high resolution transmitting electron microscopy (HRTEM) shows apparent mutilayer structure of the [FePt(2 nm)/Ag(5 nm)]10 film. We also found the good epitaxial growth of FePt on MgO [001] direction. Atomic force microscopy (AFM) observation on the surface morphology showed that the surface particle size and roughness degree decrease with increasing the Ag layer thickness.
Study on Copper Nitride Thin Films Prepared by Reactive DC Magnetron Sputtering
Authors: Li Xing Ao , Yang Jian Ping , Li Yong Tao , Wang Li Xia , Wang Hai Yun
Published: June 2011

Copper nitride thin films were deposited on glass substrates by reactive DC magnetron sputtering at various N2-gas flow rates and different substrate temperature. X-ray diffraction measurements show that the films are composed of Cu3N crystallites with anti-ReO3structure and exhibit preferential orientation to the [111] and [100]. The preferred crystalline orientation of the films changes with the N2-gas flow rate and substrate temperature. The N2-gas flow rate and the substrate temperature not only affect the crystal structure of films but also affect the deposition rate, the resistivity and the microhardness of the Cu3N films.
DLC Films Synthesized on the Ti6Al4V Alloy Surface by Plasma Gun at an Atmospheric Pressure
Authors: Chen Fei , Chen Jia Qing , Zhou Hai , Li Cheng Ming
Published: June 2011

At atmospheric pressure, Diamond-Like Carbon (DLC) thin films were deposited on the Ti6Al4V alloy surface by a DBD plasma gun at low temperature (<350°C), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin film under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0μm thickness by plasma gun. The surface roughness Ra is about 13.23nm. The DLC thin film has a good adhesion of critical load 31.0N. It has been found that the DLC thin film has excellent friction and wear-resistant behaviors. The friction coefficient of the Ti6Al4V substrate is about 0.50 under dry sliding against the steel, while the DLC thin film experiences much abated friction coefficient to 0.15 under the same testing condition.
The Microstructure, Resistivity and Infrared Emissivity of ITO Film with O/Ar Ratio Variation in Al2O3 Buffer Layer
Authors: Chao Yi Peng , Tang Wu , Weng Xiao Long , Deng Long Jiang
Published: June 2011

ITO films with different oxygen-argon ratios varies from 0 % to 8 % for Al2O3buffer layer have been fabricated by magnetron sputtering on soft PET substrate. The microstructure, resistivity, transmittance in visible light range and infrared emissivity were measured by XRD, four-point probe technology, UV-Vis spectrophotometer and Fourier Transform Infrared Spectroscopy (FTIR) as a function of different oxygen-argon ratios of Al2O3buffer layers, respectively. It can be found that the (222) plane crystallization improves with the increase of O/Ar ratio, (622） peak under 2% O/Ar ratio and (440), (211) peaks under 8% O/Ar ratio appear, respectively. The resistivity is also influenced significantly by the O/Ar ratio, though the variation of resistivity is not sensitive to O/Ar ratio higher than 2%. The results reveal that the best ITO film performance under the oxygen-argon ratio 2% for Al2O3buffer layer. It is also found that surface roughness and interface state play an important role in the variation of transmittance and emissivity. The emissivity of all the ITO films deposited on Al2O3buffer layer is dominated by both sheet resistance and surface morphology.