bluuebunny/crossref_metadata_2025 huggingface dataset:
Martensitic Transformation and Metamagnetic Shape Memory Effect in Ni46Co4Mn37in13 Heusler Alloy
Authors: Jing C. , Zhang H. L. , Li Z. , Yu D. H. , Cao S. X. , Zhang J.C.
Published: June 2011

The phase transition strain and magnetostrain during the martensitic transformation have been systematically investigated in Ni46Co4Mn37In13 Heusler alloy. A large phase transition strain with the value of about 0.25% upon martensitic transition has been observed, which is much larger than that in other metamagnetic shape memory alloys. In addition, such phase transition strain can be also obtained by the field change of about 50 kOe, exhibiting a large metamagnetic shape memory effect with nonprestrain. This behavior can be attributed to magnetoelastic coupling, which is caused by large difference in Zeeman energy between austenitic and martensitic phases.
The Effect of Vacancy on the Phase Stability of TiNi Shape Memory Alloy from First-Principle Calculation
Authors: Yue Bin , Li Yan , Zhang Fei
Published: June 2011

The effect of vacancy on the phase stability of TiNi shape memory alloy has been investigated by the first-principle method based on the density functional theory with generalized gradient approximation. The formation energy, formation heat, formation enthalpy per atom and density of states (DOS) of TiNi alloy with and without vacancy are calculated. The results indicate that the favorable point defect is Ni vacancy in both B2 and B19’ phases of TiNi alloy. The existence of vacancy increases the formation enthalpies per atom difference and thus decreases the phase stability. The DOS values at Fermi level of martensitic phases are lower than that of austenite phases in both perfect TiNi and TiNi with Ni vacancy, indicating the natural transformation from austenite to martensite upon cooling.
The Polymerization and Performance of Fluorinated Acrylic Copolymer with Low Surface Energy
Authors: Zhang Yan , Zhang Zhan Ping , Qi Yu Hong , Gao Xin Rui
Published: June 2011

Fluoro-polymer is of great importance as coating materials because of their excellent resistance to high temperature, chemicals and organic solvents. In the interest of researching low surface energy coating, a kind of copolymer was prepared by solution polymerization method, using methyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate and perfluoroalkyl ethyl acrylate whose length of fluorinated carbon chain was from 6 to12. Solid content, monomer conversion rate and viscosity of the copolymer were measured. Parallel experiments were separately carried out with different contents of initiator and fluorinated monomer. The results showed that the water contact angle of the film becomes bigger with the increase of the content of fluorinated monomer, with the biggest value in 108° when the content of fluorinated monomer content is 30 wt%, but only changing little after content of fluorinated monomer reaches up 15 wt%. The results indicated that the copolymer can offer the best property combination when the contents of fluorinated monomer and initiator were 15 wt% and 1.8 wt%.
Effect of Annealing on Formation and Microstructure of ZnTiO3 Thin Films by DC Reactive Magnetron Co-Sputtering
Authors: Huang Yen Lin , Lee Ying Chieh , Tsai Du Cheng , Shieu Fuh Sheng
Published: June 2011

Thin films of zinc titanate (ZnTiO3) can be produced on Si(100) substrates at room temperature by DC reactive magnetron co-sputtering with Ti, Zn as the target and O2 as a reactive gas. In this work, the influence of annealing temperature (500–900 °C) on microstructure and formation of ZnTiO3 thin films were investigated. The samples are characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, electron spectroscopy for chemical analysis. As-deposited films have an amorphous columnar structure. The crystallization phenomenon was observed with annealing temperature of 500 °C. After 600 °C 2 h annealing, crystalline phase with ZnTiO3 (hexagonal) and TiO2 (rutile) could be obtained and coexisted. Furthermore, the unit cell size of the ZnTiO3 and TiO2 crystal is a = ~5.062 Å, c = ~ 13.87 Å and a = ~4.58 Å, c = ~ 2.95 Å.
Formation and Optical Properties of Polycyclic Aromatic Cluster in Nanocrystalline Diamond Film
Authors: Wu Nan Chun , Xia Yi Ben , Wang Lin Jun
Published: June 2011

With electron assisted chemical vapour deposition technology, some nanocrystalline diamond films have been deposited, which precipitate polycyclic aromatic clusters in the film matrix. Optical properties of the films have been characterized. The results of characteristics show that Raman and photoluminescence spectrum of the films conform to identity of pyrene except for diamond peaks; photoluminescence emission spectrum of the films show stronger emission peaks at 385nm and 470nm. Our results show that purer polycyclic aromatic clusters of four fused sixfold ring, which are the same as pyrene in structure, can form in the nanocrystalline diamond film matrix by bombarding the films with electrons.
Investigation of Phase Transitions in Stacked GeTe/SnTe and Ge2Se3/SnTe Chalcogenide Films
Authors: Bai Fei Ming , Zhang Huai Wu , Gupta Surendra , Kurinec Santosh
Published: June 2011

Phase transitions in stacked GeTe/SnTe and Ge2Se3/SnTe thin layers for potential phase-change memory applications have been investigated by X-ray diffraction using an area detector system and by scanning electron microscopy. The as-deposited underlying GeTe or Ge2Se3 layer is amorphous, whereas the top SnTe layer is crystalline. In GeTe/SnTe stack, the crystallization of GeTe phase occurs near 170°C, and upon further heating, GeTe phase disappears, followed by the formation of rocksalt-structured GexSn1-xTe solid solution. In Ge2Se3/SnTe stack, the phase transition starts with the separation of SnSe phase due to the migration of Sn ions into the Ge2Se3 layer. The migration of Sn ions and the formation of SnSe are believed to facilitate the crystallization of Ge2Se3 solid solution at ~360°C, which is much lower than the crystallization temperature of Ge2Se3, therefore consuming less power during the phase transition.
Electrical and Optical Properties of ZnO-Doped Zr0.8Sn0.2TiO4 Thin Films on ITO/Glass Substrates by RF Magnetron Sputtering
Authors: Hsu Cheng Hsing , Yang His Wen , Lin Jenn Sen
Published: June 2011

Electrical and optical properties of 1wt% ZnO-doped (Zr0.8Sn0.2)TiO4thin films prepared by rf magnetron sputtering on ITO/Glass substrates at different rf power and substrate temperature were investigated. The surface structural and morphological characteristics analyzed by X-ray diffraction (XRD) and atomic force microscope (AFM) were found to be sensitive to the deposition conditions, such as rf power and substrate temperature. The selected-area diffraction pattern showed that the deposited films exhibited a polycrystalline microstructure. All films exhibited ZST (111) orientation perpendicular to the substrate surface and the grain size as well as the deposition rate of the film increased with the increase in both the rf power and the substrate temperature. Optical transmittance spectroscopy further revealed high transparency (over 60%) in the visible region of the spectrum.
Preparation and Characterization of Diamond-TiC-Ti-Ag/Cu Gradient Metallization System
Authors: Liu Jin Long , Li Cheng Ming , Chen Liang Xian , Zhang Ying Ying , Hei Li Fu , Lv Fan Xiu
Published: June 2011

A novel kind of diamond-TiC-Ti gradient interlayer has been successfully obtained between self-standing diamond and Ag/Cu films by combining Ti ion implanted into the achieved CVD diamond films by MEVVA with depositing Ti layer and by magnetron sputtering and annealing in vacuum. In the metallization system, RF sputtering was also utilized to deposit Ag/Cu films consistent with target composition based on orthogonal experimental design. Transition from Ti to Ag/Cu could be controlled to distribute gradually through adjusting both of their deposition powers. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results show TiC is formed and the content of Ti increases gradually in diamond and decreases in the sputtering depth profiles of the Ti-Ag/Cu film. Raman spectroscopy indicates the effects of Ti ion implantation on the structure of diamond. Gradient design leads to order-of-magnitude improvements in adhesion between diamond and Ag/Cu films, which can be a good choice for heat sink.
Study on W-Mo-Y Multi-Elements Alloying and Plasma Nitriding on Q235 Steel
Authors: Gao Yuan , Li Bing , Chen Xuan Nan , Huang Xue Feng , Zhang Wei , Yuan Lin
Published: June 2011

Using plasma alloying technique, Q235 steel was firstly treated by W-Mo-Y Multi-elements alloying followed by plasma nitriding process. The effects of process parameters on alloying layer were studied. The structure, composition, phase and micro-hardness of alloying layer were analyzed by metalloscope, XRD, SEM and microhardness tester. Results show that the microstructure of W-Mo-Y alloying layer is columnar crystal, and W, Mo contents decrease from the outside to the inside. The element Y is distributed mainly at the grain boundaries. The phase of alloying layer consisted of Fe, Fe3Mo, Fe17Y2 and the solid solution of (W, Mo, Y) in α-Fe. After plasma nitriding process, the co-diffusion layer is strengthened and large amounts of nitrides form and dispersedly distribute in the alloying layer. The phase of alloying layer consist of Fe4N, Fe3Mo, Fe, MoN, Mo2N, W2N, WN. The average micro-hardness of alloying layer is 850HV0.05. And then the wear tests were conducted. Compared with untreated samples, the wear resistance of alloying layer is improved by 2 times under abrasive wear conditions.
Structure and Magnetic Properties of CoFe2O4 Nanocrystal Thin Films Prepared by Sol-Gel Method
Authors: Sun Jian Rong , Wang Zhi Guang , Wang Yu Yu , Li Fa Shen
Published: June 2011

Thin films of CoFe2O4 spinel ferrite were prepared on silicon (100) substrates at low temperature by means of a modified polyvinyl alcohol processing, and the structure and magnetic properties as a function of the only one varied calcination temperature were investigated in detail and optimized. The CoFe2O4 ferrite films had a single phase spinel structure and were well-crystallized at temperature above 600 °C, which is much lower than the required temperature in the traditional ceramic method (about 1000 °C). The films annealed at and above 500 °C for 1h showed the grain sizes between 9 and 40 nm, and exhibited high coercivities and high saturation magnetization. Co-ferrite films prepared by sol-gel method and annealed at 700 °C had excellent potential for important technological applications, such as information storage and magnetooptical devices.
Growing Behaviors of Oxidation Film on the Surface of Liquid Sn-0.68Cu-0.3Ag-X Solder
Authors: Du Chang Hua , Yin Li Meng , Luo Yi , Chen Fang , Zhao Hai Jian
Published: June 2011

A lead-free hypoeutectic solder Sn-0.3Ag-0.68Cu-X with low sliver content was prepared by a new process. By the method of skimming surface oxidation film at static state, the growing behaviors of oxidation film on the surface of liquid solder alloy were studied. The experimental results show that the growth rate of oxidation film on the surface of liquid solder decreases greatly after surface modification process. Before the surface modification process, the growth behaviors of oxidation film on the surface of liquid solder obey parabolic law which changes with variation of time. After surface modification, the growth behavior of oxidation film of liquid solder is transformed into obeying logarithmic law. The formation rate of oxidation slag on the surface of liquid Sn-0.3Ag-0.68Cu-X solder can be reduced to 0.36 mg/cm2.min at 260 °C under standard test conditions. Conceptually, the atomic-doping X (X=Ga, In, Bi, Ge, Sb, Ni and P) was absorbed to the surface of liquid solder according to Gibbs absorption equation and entered into oxidation film, which is prone to form more compact oxidation film to prevent the oxidation on the surface of liquid solder.
Influence of Magnetic Field Thermal Annealing on the High- Frequency Performance of the FeCo-Based Granular Thin Films
Authors: Lu Guang Duo , Zhang Huai Wu , Tang Xiao Li , Li Yuan Xun , Zhong Zhi Yong
Published: June 2011

A series of FeCoHfO granular films were fabricated by reactive DC magnetron reactive sputtering at varying partial pressure of oxygen and annealed by magnetic field thermal annealing. By using magnetic field annealing method suitably, the soft magnetic properties of FeCoHfO granular thin films are improved obviously. The optimal annealing temperature and annealing time are 350 °C and 20 minute, respectively. The films with desired properties of low coercivity, Hc~2Oe, relatively high saturation magnetization, 4pMs~20.5 kG, high anisotropy field Hk~50Oe, and high electrical resistivity r ~ 1875mWcm and natural ferromagnetic resonant frequency about 3 GHz have been obtained.
Fabrication of Surface Energy Gradients Using Self-Assembled Monolayer Surfaces Prepared by Photodegradation
Authors: Liu Chang Song , Zheng Dong Mei , Zhou Ji Gen , Wan Yong , Li Zhi Wen
Published: June 2011

A new technique, direct photodegradation of self-assembled monolayers (SAM), to obtain surface energy gradients on Si substrates was demonstrated. The gradient surface, with hydrophobic to hydrophilic gradients, was prepared by two steps: Firstly, a homogeneous fluoroalkylsilane SAM film was deposited by a chemical vapor deposition on a Si substrate. Secondly, a controlled photodegradation technique was directly applied to the homogeneous FAS-SAM surface. The surface energy gradient was then obtained due to the different intensity of photoirradiation in the different positions along the photodegraded path on the SAM surfaces. The resulting surface displayed a gradient of wettability (with the contact angle of water changing from 55° to 18°) over a distance of 4.2 mm. The water droplet was driven by surface energy gradient and spontaneously moved from the hydrophobic to hydrophilic surface. During the moving process, the water droplet accelerated firstly and then decelerated. The peak velocity was about 23.3 mm/s. The velocity is dependent on the gradient of the surface energy.
Monodispersed Protein Stabilized Silver Nanoprisms: Synthesis, Optical Properties and Surface-Enhanced Raman Scattering Application
Authors: Zhang Dan Hui , Liu Xiao Heng , Wang Xin
Published: June 2011

Protein stabilized, water soluble silver nanoparticles are essential for biomedicine and biotechnology. The abundant protein such as gelatin and bovine serum albumin (BSA) has a remarkable ability of binding and transporting materials across cell membrane that makes it ideal for drug delivery and very useful for pharmaceutical industry. In this article, silver nanoprisms were synthesized by reacting an aqueous solution of silver nitrate with proteins such as gelatin and bovine serum albumin at different conditions, where proteins provided the dual function of Ag (I) reduction and Ag(0) prism-like structures formation. The solution exhibited an excellent colloidal stability by the visible observation. UV-vis spectra and transmission electron microscopy (TEM), revealed the formation of well-dispersed Ag nanoprisms with different sizes. Furthermore, the ﬂuorescence intensity of proteins was drastically quenched in presence of Ag nanoprisms from the results of fluorescence spectra. The surface enhanced Raman scattering spectrum of anisotropic silver nanoprisms was also presented.
Morphological Control of Calcium Carbonate Particles by a Novel Polymer-Surfactant Aggregate
Authors: Tang Hua , Yang Xiao Fei , Wu Qiong , Li Chang Sheng , Yan Xue
Published: June 2011

In this paper, calcium carbonate particles with unusual morphologies could be successfully synthesized by a precipitation reaction of sodium carbonate with calcium chloride in the presence of a novel polymer-surfactant aggregate consisting of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG) and sodium dodecyl sulfonate (SDS). The as-prepared products were characterized with scanning electron microscopy and X-ray diffraction. The results showed that the SDS concentrations, the molar ratio of CO32-to Ca2+(R), and the reactive temperature in the mixed system turned out to be important parameters for control of morphologies of the as-prepared CaCO3particles. Various unusual crystal morphologies, such as hollow microsphere, cubic, and rombehedra, etc., can be obtained depending on the experimental conditions. Moreover, the formation mechanisms of calcium carbonate with different morphologies were discussed.
Oxygen Plasma Induced ZnO-CuO Nanostructure Growth on a Brass Substrate by Atmospheric-Pressure Plasma Jet
Authors: Chen Hao Long , Liou Zin Ching , Lin Shian Jang
Published: June 2011

A convenient method for direct and large-area growth of one-dimensional (1-D) CuO and ZnO nanostructures on a conductive brass substrate has been developed. The ZnO and CuO nanostructures have been simultaneously induced and growth on a brass (70Cu-30Zn alloy) substrate by using an atmospheric-pressure plasma jet (APPJ) with pure oxygen as the reaction gas in an ambient environment. Various one-dimensional (1-D) nanostructures such as nano-particles, nanowires, nanobelts, nanocombs, and nanosheets have been in situ grown on the brass substrates under different plasma treatment times. The plasma power of 150W and scanning speed of sample stage 1 mm/sec with different treating times were used in plasma surface treatment processing. The nano-scaled ZnO and CuO formation and its structure were characterized by means of grazing-incidence X-ray diffraction, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The results showed that the nano-scaled CuO and ZnO growth process was as follows: nano-particles, nano-crystal clusters then nano-crystal columns with increasing plasma treatment times. The growth of nano-scaled oxide formed in sequence that CuO was first grew on the brass substrate then ZnO. The morphologies of nano-scaled ZnO resembled bulbs and long-legged tetrapods. However, the morphologies of nano-scaled CuO were likely bulbs and flake nanostructures. This approach could prepare CuO and ZnO nanostructures on a brass substrate without size limitations. The possible growth mechanisms and structure of nano-scaled CuO and ZnO are discussed in this paper. The simplicity of the preparation procedure and the potential technological of the product were be interested in this study.
Performance Evaluation of Nano-Montmorillonite/SBS Modified Asphalt Paving Mixtures
Authors: Tang Xin De , Kong Xiang Li , Huang Fang , Li Jun
Published: June 2011

To provide the valuable references for pavement materials applied in various climatic zones, a series of asphalts paving mixtures including common asphalt mixture, SBS modified asphalt mixture and nano-montmorillonite (NMMT)/SBS composite modified asphalt mixture were designed. Marshall tests were carried out to evaluate the effect of different modifiers on the property of these asphalt paving mixtures. Compared with the other two mixtures, NMMT/SBS composite modified asphalt shows fine mechanical performance and moisture susceptibility. These results indicate that NMMT/SBS as a composite modifier can result in excellent properties for asphalt paving mixture.
Phase Diagram of MgCl2-LiCl-Na2­SiO3-H2O System at 200°C and Synthesis of Hectorite
Authors: Yin Xiao Jie , Jia Yong Zhong , Jing Yan , Yao Ying , Ma Jun
Published: June 2011

Phase diagram of MgCl2–LiCl–Na2­SiO3–H2O (MLSH) system at 200°C was reported. The phase diagram was designed according to the hydrothermal system in which hectorite was formed. The solid phases were characterized by X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Lithium silicate, hectorite and karpinskite were observed as solid phases. The presence of hectorite in solid phases was decided by the molar ratio of MgCl2 and Na2SiO3 in the system. When the Mg/Si molar ratio exceeded a certain value, little hectorite was formed even though there was a large amount of LiCl in the system. The reason may be that it was difficult for Li+ to replace the Mg2+ in the framework. As a versatile nanomaterial, hectorite could be synthesized using concentrated natural brine as starting materials by hydrothermal method at 200°C. The phase diagram could be used as the theoretical principle for synthesis of hectorite and comprehensive utilization of concentrated natural brine.
Preparation and Aging Property of Nannocomposite CaCO3/SBS Modified Asphalts
Authors: Tang Xin De , He Zhong Guo , Man Xin Kai , Zhang De Yang
Published: June 2011

Composite modified asphalts with nanoscale calcium carbonate (CaCO3) and SBS were prepared by melt blending. Rolling thin film oven test (RTFOT) was carried out to study the aging property. The results demonstrate that both nano CaCO3 and SBS show homogeneous dispersion in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Influence of nano CaCO3 on the properties of SBS modified asphalts appears as a decreasing penetration, an increasing softening point, and a decreasing ductility. The anti-deformation ability under low temperature of nano CaCO3/SBS modified asphalts improved significantly. The softening point of nano CaCO3/SBS modified asphalt decreases after aging, in contrast to that of the base asphalt, which can be ascribed to the different rheological peoperties between nano CaCO3/SBS modified asphalt and the base asphalt. Compared with that of SBS modified asphalt, the anti-ageing property of nano CaCO3/SBS modified asphalts improved significantly. This indicates that nano structure of CaCO3 in modified asphalt can prevent oxygen from diffusing and permeating in matrix and the thermo-oxidative ageing of base asphalt and SBS slows down.
Preparation and Characterization of Core-Shell γ-Fe2O3@SiO2@ Al2O3 Magnetic Catalyst
Authors: Yu Lian Qing , Zhong Xiao Liang , Zhang Ya Ping , Liu Chen Guang
Published: June 2011

Magnetic catalyst was made of magnetic core and surface coating layer and obtained a core-shell complex materials. The magnetic γ-Fe2O3 core has a relatively higher saturation magnetization, coercivity and good thermal stability even at 500°C. In order to prevent magnetic core forming spinel structure and migrating of Fe3+, a layer of silicon dioxide was coated by sol-gel method. During the process iron atoms scattered in –Si-O-Si- network and produced a γ-Fe2O3@SiO2 structure. Finally, the γ-Fe2O3@SiO2 powder was put into the alumina sol and evenly sprayed into a column of oil, after calcination the carrier of alumina layer was prepared.
Preparation and Characterization of the Decarbonization Preventing Nano-Coating Applied in Spring Steel Protection
Authors: Wang Xiao Jing , Ye Shu Feng , Xu H.W. , Wei L.Q. , Zhou Xun , Chen Y. F.
Published: June 2011

Surface decarburization is one of important issues in spring steel production. The novel decarbonization-resistant nano-coating has been successfully fabricated, by using a low-cost, and easily accessible bauxite minerals and other additional components, including magnesia, silicon carbide，glass powder and agglomerant, which is used to prevent spring steels from being decarburized during the hot-rolling process. The microstructure of the protective nano-coating is observed by means of X-ray diffraction, TG-DTA, metalloscope and so on. It is found that even if some glass ceramic exists within the coating in the initial lower temperature (950°C~1000°C) the decarbonization-preventing coating still presents decarburization resistance up to 72.2%. Furthermore, the protective ration reaches to 100% when the heating temperature rises to range (1050°C~1100°C). The excellent decarbonization preventing properties are attributed to the formation of glass ceramic and pleonaste, which hinders the second interdiffusion of oxygen and carbon.
Rapid Detection of Copper by the Carbon Nanotube Chemically Modified Electrode
Authors: Yang Rong , Jiang Qi , Liu Peng , Chen Qin , Wang Yi Jia , Zhao Yong
Published: June 2011

Since carbon nanotube (CNT) was discovered, it has been focused due to its distinctive structure and performance. In electrochemical field, CNT can be used as the modified material to prepare CNT chemically modified electrode (CNT-CME) and shows excellent electrochemical performances. A CNT-CME was obtained via growing CNT on the graphite electrode in situ by catalyst chemical vapor deposition. The obtained grown in situ CNT-CME (named as GSCNT-CME) had shown good testing accuracy and good electrochemical response. In this paper, the GSCNT-CME was used to detect copper ion in water via the cyclic voltammetry. The results showed that the linear range of GSCNT-CME to copper was from 1.0×10-5 to 2.5×10–3 mol/L in 0.6 mol/L H2SO4 supporting solution (with the scanning rate of 10 mV/s). The linear range was exactly the most in need of detection Cu2+ concentration (from 1.57×10-5 to 1.0×10–3 mol/L) according to the Ⅱ, Ⅲ and Ⅳ drinking water national required standard (GB3838-83, ≤1.57×10-5 mol/L). And the detection limit was 2.64×10-6 mol/L (S/N=3). At the same time, the recovery of copper ion was 93.04%-99.79%. The results indicated that GSCNT-CME had the important value of practical application to rapid detect copper ion in water.
Sputtering Phenomena of ZnS Nanomaterial by Impacting of High-Energy Electron in a Transmission Electron Microscope
Authors: Zhang Ke Jie , Zhou Hong Yan , Liu Xiao Heng
Published: June 2011

An interesting sputtering phenomenon was shown when ZnS nanomaterial was irradiated by high-energy beams in a transmission electron microscope (TEM). Almost sputtered nanoparticles were spherical and well-dispersed. The sizes of deposited ZnS nanoparticles showed a good gradient distribution based on their distance away from the sputtering target. These nanoparticles had gradual changes in diameter from about 1 to 15 nm. This research may afford a simple and efficient method to prepare well-dispersed semiconductor nanocrystals in a small size range.
Synthesis of Crystalline ZnSe Nanowires by Pulsed Laser Deposition for Application in Polymer-Inorganic Solar Cells
Authors: Lai Ju Shui , Chen Li , Fu Xiao Niu , Sun Jian , Ying Zhi Feng , Wu Jia Da , Xu Ning
Published: June 2011

Crystalline ZnSe nanowires have been grown by pulsed-laser deposition on catalyst-coated substrates. On 300-400 °C catalyst-coated silicon (100) substrates, the crystalline ZnSe nanowires can be grown densely with the middle diameters about 40 nm, and the length about 400 nm . The as-grown nanowires were well crystalline and base-grown. They have potential applications in solar cell based on polymer/inorganic hybrid system for their properties of good electron-conductance and high ratio surface area. Based on the ZnSe nanowires cathode, a five-layer composite structure of polymer/inorganic hybrid solar cell has been designed. Before the growth of nanowires, a silver layer with a thickness of about 100 nm was deposited on the Si substrate as the back electrode and catalyst layer by the method of PLD. Then ZnSe nanowires were deposited on the Ag-coated substrate. Subsequently, poly (3-hexylthiophene) (P3HT) and PEDOT: PSS were spin-coated on the ZnSe nanowires. After that, a layer of Clevios PH1000 was also spin-coated on the composite sample as front electrode. At last, the solar cell was encapsulated with epoxy resin. Short circuit current about 0.44mA has been tentatively observed in this complex system.
Thermophysical Performances of Al2O3-Water Nanofluids and Its Heat Transfer Enhancement in Heat Pipe
Authors: Li Dong Dong , Zhao Wei Lin , Li Jin Kai , Guan Yan Xiang , Liu Zong Ming
Published: June 2011

Al2O3-water nanofluids with volume concentration of 0.1%~0.5% were prepared by a two-step method, the thermophysical parameters such as thermal conductivity, viscosity and surface tension were measured, The results showed that the thermal conductivity of Al2O3-water nanofluids increased with increasing temperature and volume concentration, while the viscosity decreased with increasing temperature but increased with increasing volume concentration, in contrast to the thermal conductivity, the surface tension significantly decreased with increasing temperature and volume concentration. Furthermore, Al2O3-water nanofluids with 0.5% volume concentration were added into heat pipe. The experimental measurements showed that the Al2O3-water nanofluids have improved the heat transfer performance of heat pipe and the heat transfer coefficient of the heat pipe with Al2O3-water nanofluids enhanced by 85.7% when compared with the heat pipe with deionized water.
Synthesis and Characterization of Core-Shell Structured Bimagnetic Cobalt-Coated Iron Nanoparticles
Authors: Su K.P. , Liu Zhong Wu , Shan X.X. , Zheng Z.G. , Zhong X.C. , Yu Hong Ya , Zeng De Chang
Published: June 2011

Core-shell structured nanoparticles with ferromagnetic core (Fe) and shell (Co) were prepared by a chemical reduction method. By adjusting the deposition parameters, the core-shell particles with various Fe:Co molar ratios were obtained. The saturation magnetization decreased with the increase of Cobalt content. The properties of core-shell nanoparticles synthesized under a magnetic field were compared with those prepared without a magnetic field. For the nanoparticles prepared without magnetic filed, the coercivity (Hc) increased with increasing Co content due to the large anisotropy of Co, whereas for the nanoparticles prepared under a magnetic field, theHcwas much lower. The ZFC/FC curves suggested that these particles were ferromagnetic at room temperature. The anisotropy constant K at 340K for core-shell nanoparticle is estimated to be 0.83×105erg/cm3. The second ferromagnetic phase transition may occur at the temperature lower than 25 K, which led to a drastic change of magnetization at low temperatures.
The Microalloying Effects in Cu-Based Bulk Metallic Glasses
Authors: Yue Li Jie , Han Jin Sheng , Xie Kun
Published: June 2011

The glassy alloy rods of Cu50Zr43Al7, (Cu50Zr43Al7)100-xYx(x=2,5) and (Cu50Zr43Al7)100-xAgx(x=6,7) with diameters of 3.0 mm were prepared by copper mold suction casting method. The influence of adding Ag and Y to Cu50Zr43Al7 metallic glass on glass formation ability (GFA) and thermal stability was studied by means of X-ray diffraction analysis (XRD) and differential scanning calorimetry (DSC). The results show that Ag and Y appropriate micro-addition enhance the glass formation ability and thermal stability of the Cu-Zr-Al metallic glass. The effect of Ag is better than that of Y. The addition of Ag causes a increase of the reduced glass transition temperature (Trg) of (Cu50Zr43Al7)100-xAgx alloy from 0.618 at 0 at.% Ag to 0.628 at 7 at.% Ag. The width of the supercooled liquid region of Cu43Zr43Al7Ag7 glassy alloy increases about 25K compared with that of Cu50Zr43Al7, and the γ value of Cu43Zr43Al7Ag7 reaches 0.433. The electrochemical corrosion behaviors of Cu50Zr43Al7, (Cu50Zr43Al7)100-xYx(x=2,5) and (Cu50Zr43Al7)100-xAgx(x=6,7) metallic glasses in 3.5% NaCl solution were investigated by potentiodynamic polarization method. It is found that corrosion resistance of all amorphous alloys is better than that of the corresponding crystalline alloys. The Ag and Y micro-addition improve corrosion resistance of Cu50Zr43Al7 metallic glass. The corrosion current density of Cu43Zr43Al7Ag7 metallic glass decreases 1~2 orders of magnitude compared with that of Cu50Zr43Al7.
Carbon Nanofibers Preparation Using Carbon Monoxide from the V-Type Pyrolysis Flame
Authors: Liu Yuan Chao , Sun Bao Min
Published: June 2011

Synthesis carbon nanofibers from V-type pyrolysis flame use simple carbon monoxide and acetylene /air premixed flame. Catalyst is transported by helium into the burner. The carbon nanofibers from the sampling probe were characterized by scanning electron microscope and transmission electron microscope. The influence of the fuel equivalence ratio and the flow of carbon monoxide were discussed in detail to reveal the formation rule of carbon nanofiber from the pyrolysis flame. The results indicate that carbon monoxide is a good carbon source gas for the preparation of carbon nanofibers. Under appropriate temperature and optimized flow of carbon monoxide, carbon nanofibers with good quality can be prepared from the V-type pyrolysis flame. It can be concluded that this flame method is effective for the preparation of carbon nanofibers.
Electrospun Europium Complex/Polymer Composite Microfibers and Its Modified Photoluminescence Properties
Authors: Yin Hong Xing , Long Yun Ze , Yu Fang , Zhao Shuai Jiang , She Xi Lin
Published: June 2011

Ribbon-like microfibers of a new composite of europium complex Eu(aspirin)3(Phen) (aspirin is acetylsalicylic acid; Phen represents 1,10-phenanthroline) and polystyrene (PS) were prepared successfully by electrospinning with different mass ratios of Eu(aspirin)3(Phen) complex to PS = 1:10, 1:40 and 1:160. The microfibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and fluorescence spectrophotometry. It was found that the fibers displayed excellent photoluminescence properties compared with rare-earth complex. The photoluminescence intensity and the emission intensity of the peak at 616 nm (5D0→7F2) of Eu-ions increased with the Eu(aspirin)3(Phen) loading. No obvious fluorescence quenching was observed. Further discussion on the structural and optical properties of the microribbons was presented. This kind of materials might be expected to be applied for optical or optoelectronic devices.
Long Si3N4 Nanowires Fabricated by PECVD
Authors: Song Jing Wei , Ma Xi Ying
Published: June 2011

The paper presents the fabrication of Si3N4 nanowires prepared on Si substrate by plasma-enhanced chemical vapor deposition (PECVD) technology. The nanowires were formed using silane (SiH4) and nitrogen (N2) as reactive gases under the action of Fe catalysts. They are characteristics of superlong straight and flexural types observed by field emission scanning electron microscopy (FESEM). The former with a length of 3.96 mm has smooth surface and uniform diameter resulting from an orientation growth process, while the latter is 5.20 mm formed by two nanowires twisted together with a squeezing growth way. A growth model has been developed for the formation of the nanowires, and the growth mechanism of the nanowires has been discussed. The straight and flexural Si3N4 nanowires can be used as nano-scaled bridge, spring, and cantilever in the fabrication of nano-machine systems.
Investigation on Compression Behavior of SiC/Al Co-Continuous Composites
Authors: Zhao Long Zhi , Zhao Ming Juan , Li Na , Zhang Xiao Lan , Yan Hong
Published: June 2011

Compression behavior of a novel type of SiC/Al co-continuous composites was investigated using the finite element method and a new constitutive model were presented in this paper. The results show that the new constitutive model of the co-continuous composites can predicate the compression behavior of the composites accurately according to the simulative data. The fitting curve of the compression behavior achieved from the constitutive formula accords with the simulation results, which improves the reliability of the simulation on composites.
Multiscale Microstructure of Chafer Cuticle
Authors: Chen Bin , Yuan Quan , Yin Da Gang , Fan Jing Hong
Published: June 2011

The observation of scanning electron microscope (SEM) shows chafer cuticle is a kind of biocomposite which possesses multiscale microstructural characteristic. Under a relative small magnification of the SEM, it is found that the cuticle consists of chitin-fiber layers and protein matrix and that the fibers in two adjacent fiber layers have different directions, which composes a kind of fiber-crossed microstructure. Under a relative large magnification, it is observed that the many chitin fibers in the crossed fiber layers are furcated fibers, which exhibits a kind of fiber-furcated microstructure. The maximum pullout force of the fiber-furcated microstructure is investigated and compared with that of the fiber-non-furcated microstructure through their representational models. It shows that the maximum pull out force of the fiber-furcated structure is distinctly larger than that of the fiber-non-furcated structure.
Microstructure Evolution and Analysis of a Single Crystal Nickel-Based Superalloy during Tensile Creep
Authors: Zhang Shu , Tian Su Gui , Su Yong , Qian Ben Jiang
Published: June 2011

By means of the finite element method (FEM) for calculating the von Mises stress and strain energy density in the cubic γ/γ′ phases, the regularity of γ′ phase directional growth is investigated. Results show that the change of the strain energy density in the different planes of the cubical γ′ phase occurs during tensile creep of alloy, the cubical γ′ phase is directionally grown, along the crystal plane with bigger strain energy, to transform into the mesh-like rafted structure along the direction perpendicular to the applied stress axis. The change of the atomic potential energy, interfacial energy and lattice misfit stress is thought to be the driving force for promoting the elements diffusion and directional growth of γ′ phase.
Structural and Mechanical Properties of RT2Zn20 and RFe2-xCoxZn20(R=Y, Sm; T=Fe, Ru, Os, Co, Rh and Ir)
Authors: Chen Yi , Shen Jiang
Published: June 2011

The phase stability, crystal structure and mechanical properties of YT2Zn20 and SmT2Zn20 (T=Fe, Ru, Os, Co, Rh and Ir) compounds have been investigated by using interatomic potentials based on the lattice inversion technique. The calculated lattice constants are in good agreement with the experimental data. The lattice constants increase and Bulk modulus decrease as the transition metal T varies from 3d to 5d. The Y-based compounds with lower energies are more stable than the Sm analogs. Also, the Bulk modulus of YT2Zn20 series are larger than SmT2Zn20 series. Moreover, the mechanical properties of the quaternary compounds YFe2-xCoxZn20 and SmFe2-xCoxZn20­, such as the elastic constants and bulk modulus, have been calculated in this work. The substitution of Co atoms would decrease the cohesive energies and increase the bulk modulus of materials.
A Simple Model for Predicating Dielectric Constant of CaCu3Ti4O12-SrTiO3 Composite Ceramics
Authors: Yu Hong Tao , Zhang Wen Bo , Liu Jing Song , Cao Lin Hong , Liu Han Xing
Published: June 2011

In this work, we have proposed a simple model to predicte the dielectric constant of CaCu3Ti4O12-SrTiO3composite ceramics. The model has been established based on the analysis of composition and microstructure. Two different compositions in the composite ceramics correspond to two different grain sizes, large for CaCu3Ti4O12, and small for SrTiO3, which has been identified by the x-ray diffraction, the scanning electron microscope and the energy spectrum analysis. All specimens have been assumed to be the barrier layer dielectrics in the model, according to the complex impedance spectra. The dielectric constant of serial, parallel, and logarithmic mixture models has been discussed. Compared with the experimental results, the model shows the similar variation tendency as SrTiO3content increases.
Application of Secondary Electron Composition Contrast Imaging Method in Microstructure Studies on Cathode Materials of TWT
Authors: Li Peng , Bao Sheng Xiang , Zhang De Zheng , Zhuang Li Bo , Ma Li Li
Published: June 2011

The study of the secondary electron composition contrast imaging method have been developed with a conventional scanning electron microscope (SEM) equipped with ultra-thin window energy dispersive X-ray spectrometer (EDS). On the basis of the study of the principle of secondary electron emission, secondary electron composition contrast imaging method has been investigated, and the ranges of its application were also discussed. This method was applied in the microstructure studies on cathode materials of TWT (traveling wave tube). The results showed that, compared with backscattered electron image, the secondary electron image could also reveal composition contrast well in certain conditions. Furthermore, the resolution of secondary electron composition contrast image is higher. In some cases, the secondary electron image could distinguish impurities which might bring wrong results. In the microstructure studies on cathode materials of TWT, compared with backscattered electron image, secondary electron composition contrast imaging method is reasonable and practicable.
Creep Behaviors of a Single Crystal Nickel-Based Superalloy Containing 4.2%Re
Authors: Tian Su Gui , Qian Ben Jiang , Liang Fu Shun , Li An An , Yu Xing Fu
Published: June 2011

By the measurement of creep curves and microstructure observation, an investigation has been made into the creep behaviors and microstructure evolution of a single crystal nickel-based superalloy containing 4.2%Re. Results show that the superalloy displays an obvious sensibility on the applied temperatures and stresses in the range of the applied temperatures and stresses. During the initial creep, the cubical g¢ phase in the alloy is transformed into an N-type rafted structure along the direction vertical to the applied stress axis. After crept up to fracture, the rafted g¢ phase in the region near fracture is transformed into a twisted configuration. The dislocation climbing over the rafted g¢ phase is considered to be the main deformation mechanism of the alloy during the steady creep state, and dislocations shear into the rafted g¢ phase is the main deformation mechanism of the alloy in the later stage of creep.
Microstructure and Mechanical Properties of ULCB Steels Affected by Advanced TMCP Technology
Authors: Hou Zi Yong , Xu Yun Bo , Wu Di , Sun Wei Hua , Hu She E , Wang Guo Dong
Published: June 2011

Good combination of high strength and high toughness has been considered as a critical factor of ultra-high strength steel plates. In this paper, a novel high strength steel plate of HSLA type containing Cu with 910MPa yield strength and 1163MPa tensile strength has been developed using an advanced TMCP (thermo-mechanical control processing) technology. The steel plates provide excellent combination of high strength, toughness and deformability. Microstructural evolution and mechanical properties of this steel during hot-working have been investigated. It is demonstrated that, at the relatively higher finish rolling temperature and cooling rate, the microstructure consists of acicular and granular bainite structures and a small amount of low bainite /martensite whose lath width is approximately 200~300nm. For the as-rolled conditions, despite the high strength and so low yield ratio, impact energy about 154J and fully ductility fracture at -90°C can still be obtained as documented for as-hot rolled plates.
Analysis of Mechanical Properties of TiB2-TiC+Ni/TiAl/Ti Graded Materials Prepared by FAPAS
Authors: Liu Ze Feng , Meng Qing Sen , Chen Shao Ping , Liang L.J. , Xue P.F.
Published: June 2011

TiB2-TiC+Ni/TiAl/Ti graded materials were prepared by field-activated pressure-assisted synthesis process (FAPAS) and the mechanical properties and residual stress were investigated. Shear fracture that occurs at the interface between the cermets and TiAl with the maximum shear strength of 85.88 MPa. The residual stress and deformation induced by the thermal effect of chemical reaction and Joule heat during the synthesis process were analyzed by nonlinear finite element simulation. It is demonstrated that the maximum equivalent residual stress locate in the transition layer between the ceramics and TiAl, consistent with the shear test result.
Mechanical Properties of a Novel High-Strength Aluminum-Lithium Alloy
Authors: Yuan Zhi Shan , Lu Zheng , Xie You Hua , Wu Xiu Liang , Dai Sheng Long , Liu Chang Sheng
Published: June 2011

As a heat treatable aluminum alloy to be used in T6 and T8 temper, belongs to Al-Cu-Li system, a novel high-strength aluminum-lithium alloy 2A97 was developed. In order to improve the relationships of strength and ductility and fracture toughness, and to urge the applications in the aeronautical and aerospace industries, the effects of normal heat treatments and thermomechanical heat treatments on the mechanical properties and fracture toughness were investigated by Transmission Electron Microscope(TEM), Scanning Electronic Microscope (SEM), tensile test, and fracture toughness test. The results show that for the alloy aged at 135 °C for 24 h after quenching and 4 percent plastic deformation, its microstructures are strengthened by strain hardening and precipitation hardening, consisting of fine T1phase, θ″/θ′ phase and δ′ phase densely and homogeneously distributed in the matrix. It yields optimum relationship of strength and ductility, fracture toughness, its σ0.2, σband δ5are 454 MPa, 536 MPa, and 11.8%, respectively. It yields 43.5 MPa·m1/2of Kqvalues higher than that of 42.5 MPa·m1/2 in T6 temper. The fracture morphologies of impact tensile samples of fracture toughness test and normal tensile test were observed, indicating the dominance of intergranular failure and subintergranular failure with some dimples and trangranular failure.
Sensitivity Analysis for the Cylindrical Pressure Vessel of 16MnR Steel with the Monte-Carlo Method
Authors: Li Jun , Zhang Zheng
Published: June 2011

Probabilistic safety assessment procedure is used to evaluate the cylindrical pressure vessel of 16MnR steel, which regards defect sizes, mechanical properties and stresses as random variables. Monte-Carlo simulation is applied on calculating failure probability, which is based on the Chinese safety assessment procedure (GB/T 19624-2004). Sensitivity analysis is performed to estimate the effect of change in input parameters. The results show that failure probability may be influenced significantly by change in parameters concerning yield strength and film stress. Additionally, the different distributions of input parameters have an effect on failure probability.
Dependence of Dendritic Growth on Convention with PFM Simulation
Authors: Zhu Chang Sheng , Gui Jin , Wang Zhi Ping , Li Feng
Published: June 2011

A binary alloy PFM (Phase-Field Model) which incorporates the flow field equations is constructed considering the dependence of microstructure on convention. Al-Cu binary alloy is investigated numerically based on the model, and the reasonable computational methods is studied for solving PFM, the effect of convention on dendritic growth and microsegregation patterns is implemented successfully. The computed results indicate that, the larger convention velocity U, the more developed the upstream dendritic branches is, and the more acutely the solute composition in the upstream dendritic solid fluctuates is. But the severity of microsegregation ahead of interface reduces. Nevertheless, the more undeveloped the downstream dendritic branches, the more acutely the solute composition in the the downstream dendritic solid fluctuates is, but the severity of microsegregation ahead of interface aggravates.
Possible Association of High Urinary Magnesium and Taurine to Creatinine Ratios with Metabolic Syndrome Risk Reduction in Australian Aboriginals
Authors: Hamada Atsumi , Taguchi Takashi , Mori Hideki , Thorpe Marjorie , Yamori Yukio , Mori Mari
Published: June 2011

Background. Because of the epidemic of metabolic syndrome (MS) in Australian Aboriginals known for their higher cardiovascular mortality and shorter life expectancy, we analyzed the possible relationship of their MS risks with the current dietary custom.Methods. The subjects were 84 people aged 16–79 years. The health examination was conducted according to the basic protocol of WHO-CARDIAC (Cardiovascular Diseases and Alimentary Comparison) Study.Results. The highest prevalence among MS risks was abdominal obesity (over 60%). After controlling for age and sex, the odds of obesity decreased significantly with high level of urinary magnesium/creatinine ratio (Mg/cre) (OR, 0.11; 95% CI, 0.02–0.57;P<.05). The significant inverse associations of fat intake with Mg/cre and of fast food intake with urinary taurine/creatinine ratio were revealed.Conclusions. The high prevalence of obesity in the Aboriginal people of this area may partly be due to the reduction of beneficial nutrients intake including Mg and taurine.