bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mechanism for the Production of Coherent Structures near Wall of a Turbulent Boundary Layer Excited by Wall Local Impulse Disturbance
Authors: Wu Wei Guo , Lu Chang Gen , Xue Shi Feng
Published: March 2013

Origins of coherent structures near wall of a turbulent boundary layer has been studied by direct numerical simulation (DNS). Forming mechanism of coherent structures agrees well with DNS results. A close relationship has been found between the evolutional characteristics and factors such as the magnitude and structural distribution of the wall local impulse, and the amount of energy and the length of loading time that the initial local impulse disturbance introduces into the wall region. Moreover, these parameters play key roles in the formation of coherent structures near wall of a turbulent boundary layer. So, the wall local impulse disturbance provides the origins for inducing the formation of coherent structures in wall region of a turbulent boundary layer.
Nano Mechanical Behaviors of Hindleg Cuticle in Beetle Dorcus titanus (Coleoptera: Lucanidae)
Authors: Yang Zhi Xian , Liu Ze Hua , Guo C. , Dai Zhen Dong
Published: March 2013

Biomaterials have a hierarchical structure with outstanding mechanical properties that are far beyond those additional engineering materials. Nano indentation techniques are convenient to study the biological materials. In this paper, the nano mechanical behavors of hindleg cuticle in beetle Dorcus titanus were investigated. The results indicate that the hardness and modulus values of hindleg cuticle outside are far higher than that of inside as well as the front podomere cuticle outside has a softer stiffness than that of the middle podomere cuticle outside, which is exactly contrary to the cuticle inside anyway. The primary formation factor probably is related to the different epicuticle and exocuticle with different thickness. Mechanics theories on the stiffness, hardness, strength and toughness of biomaterials can be expected to play a key role in developing bio-inspired multi-functional and hierarchical materials in future.
Flame Retardant Properties of Two Different Synthetic Process of Ammonium Polyphosphates
Authors: Liu Gou Sheng , Liu Yue Long
Published: March 2013

Ammonium polyphosphate (APP) produced by non-P2O5 process and traditional P2O5 process were used in the intumescent flame retardant (IFR) polypropylene (PP) composite (IFR-PP). The composite was tested by limited oxygen index (LOI) and UL-94. TGA and SEM were used to study the decomposition processes. Results showed that when the ratio of APP-II/ pentaerythritol/melamine is 3/1/1, the LOI value is 33.1, and all composite could reach UL-94 V0 rating. The results showed that APP by non-P2O5 process had similar IFR properties as APP of traditional P2O5 process
Structure Evolving at Bonding Interface of Dual-Alloys Jointed with Different Method under Coupling Action of Heat and Force
Authors: Yao Ze Kun , Qin Chun , Ning Yong Quan , Chao Jing Xia , Zhang Jian Wei , Tan Zhong Gang , Zhao Zhang Long
Published: March 2013

During near isothermal forging and heat treatment structure change of bonding interface in Ti3Al/TC11 and Ti2AlNb/TC11 dual alloys jointed with different method has been investigated. The results show that the solidification structure at dual-alloy joint welded by electron beam in vacuum has evolved into forging structure, columnar grains have been changed into equiaxed grains through breaking, crystal lattatice rebuild and re-crystallizing, and the mechanical bonding plus metallurgical bonding structure at joint welded by linear friction weld has transformed into metallurgy structure altogether, because constant high temperature during near isothermal forging can cause the diffusion of alloy elements and reconstruction of lattice structure.
Preparation of Several Ionic Liquids with Excellent Friction-Reducing and Antiwear Properties
Authors: Zhang Ding Jun , Qu Chao Yun
Published: March 2013

Four ionic liquids containing dithiocarbazate were synthesized. Their antiwear and friction-reducing properties of these synthetic liquid compounds as the lubricants of a steel/steel contact were examined using an Optimol SRV oscillating friction and wear tester in ambient condition. The results indicated that the ionic liquids containing dithiocarbazate as the lubricants showed excellent friction-reducing and antiwear properties for the steel/steel pair. The introduction of the dithiocarbazate group into the molecules of the ionic liquids contributed to improve the tribological behaviour.
Research of Explosive Welding: Numerical Simulation and Analysis
Authors: Wang Xiao Xu , Wang Jin Xiang , He Yong
Published: March 2013

To improve understanding of explosive welding and relate the effect of the process variables on the physical parameters, the smooth particle hydrodynamics (SPH) method in the LS-DYNA 12.0 finite element program was adopt to simulate the process of two-layer steel explosive welding. Temperature field near the stagnation point was calculated according to the work-heat transfer theory. Finally, the formation mechanism of the interface wave was analyzed under the condition that strain field, temperature field etc. were considered. The results show that: the phenomenon of jetting and the interfacial waves observed in explosive welding were quite well reproduced in these simulations; the changing collision angle with propagation distance is directly responsible for the change in interface morphology from wavy to smooth at the welding front; the maximum stress ,strain and temperature are localised at the wavy interface zone; the maximum temperatures near the interface will be high enough under proper conditions and this will be helpful for the formation of the jet and the wavy interface.
Comparison of Conductivity of Al2O3 Nanofluids between Experiments and Maxwell Model
Authors: Yu Jin Ze , Liu Bin , Li Zhen Liang
Published: March 2013

The thermal properties of nano-fluids are affected by many factors. The effect of the diameter, mass fraction and volume fraction of Al2O3 in water on the thermal conductivity was measured by the method of hotwire. The diameter of nano-particle of Al2O3 was 10nm, 20nm, 50nm, 100nm and 500nm respectively. The mass fraction of Al2O3 in water was 10%, 12%, 15% and 20%. The results show that the diameter of the particle plays a critical role on thermal properties of the base fluid. And for the mass fraction, it will increase the thermal conductivity of the base fluid. When the size is more than 100nm, the coefficient of thermal conductivity is increased rapidly. Compared with the results calculated by the Maxwell model, the conductivity of the nanofulid with a diameter less than 10nm is consistent with the model’s result. And with the increasing of the diameter o f the nanoparticle, the deviation of the conductivity will also increase compared with the model’s results.
Investigation on Heat Transfer Performance and Mechanism of New Condensation Enhanced Tubes with Machined Surface
Authors: Wang Jian Sheng , Li Yan Zhe
Published: March 2013

At present, researchers pay close attention to heat transfer enhancement, and many new surface structures are developed. Two kinds of new condensation enhanced tubes with machined surface, namely NO.1 and NO.2, are put forward. The experimental results show that the enhanced tubes can improve condensation heat transfer evidently, which is due to the special internal and external surface structures. With water vapor as condensation medium, the enhancement ratios of total heat transfer coefficient (k) are 1.6-2.4 and 1.47-1.8 comparing with smooth tube, respectively, and the ratios of outside condensation heat transfer coefficient (ho) are 5.67-6.67 and 3-4 correspondingly. With alcohol vapor as condensation medium, the average enhancement ratios of k are 3 and 2 times as great as that of smooth tube, and the ratios of ho are 3-4.25 and 2.25-3.5 correspondingly.
Steel Truss Girder Bridge Reinforcement Removing Phase Analysis of Stress Dynamic Monitoring
Authors: Zhou Yang , Shi Jun Feng , Yu Tian Qing
Published: March 2013

By taking a simple supported concrete-filled steel truss bridge as the research object in Guangzhou, some jobs have been done such as the simulating calculation and the real-time monitoring of side span steel girder during the jacking construction procedure, and contrast analysis was conducted between the calculating stress value and the measured stress value, which may draw a conclusion that the safety could be satisfied during the jacking construction procedure
Experimental Study of Nd:YVO4/KTP Solid Laser Pumped by Diode Laser
Authors: Pei Shi Xin , Cui Fen Ping , Sun Shu Dan
Published: March 2013

Build a diode laser end-pumped Nd:YVO4/KTP solid laser system, Nd:YVO4 crystal was used as the solid laser medium, it emitting 1064nm infrad laser when it was pumped by 808nm diode laser, then the 1064nm infrad laser was changed to 532nm green laser by frequency doubling with a KTP crystal inside the optical cavity. Based on experiment, the relationship between diode laser power output and diode laser injection current, the relationship between laser pump power and 532nm green laser output, and the other factors possibly affecting 532nm laser output which include KTP phase match angle, pump light focus position and all-solid-state-laser (ASSL) cavity length was also studied. The experimental results show that to increase the output of 532nm green light needs to improve the pump diode laser power, shorten the length of the solid laser cavity , focus the pump laser to the middle of the Nd:YVO4 crystal, and choose correct KTP crystal phase-matching angle.
Synthesis and Solution Self-Assembly Behavior of Porphyrin Tethered by Fullerene C60
Authors: Sitienei Wilson Lelei , Wangatia Lodrick Makokha , Zeng Ting , Sun Bin , Zhu Mei Fang
Published: March 2013

This paper focuses on the synthesis, spectroscopic studies and self-assembly behavior of porphyrin phenyl linked fullerene C60 dyad, which included COOH groups in its fullerene unit so as to promote its adsorption onto TiO2. UV-Vis spectrum and steady-state fluorescence spectrum measurement, showed that the self-assembly of this compound in different solvents with different polarities. The results show that the soret absorption peak slightly blue shifted by 5 nm in acetonitrile and 2 nm in tetrahydrofuran, while the soret peaks in toluene solution was the same as in chloroform. Increasing concentration from 1x10-6 mol/L to 2x10-5 mol/L in chloroform resulted into aggregation, also the slight red shifting on cooling from 900C to 100C was observed from a temperature dependant UV-Vis absorption spectra, thus indicates aggregation. All these features may indicate presence of J-type aggregation happening in 4-methylphenyl-H2porhyrin-fullerene C60-COOH. In addition, the fluorescence of 4-methylphenyl-H2Porhyrin-fullerene C60-COOH has been quenched compared to that of pure 4-methylphenyl-H2porhyrin-OH under the same concentration. Therefore, this novel material design may find good application in photoelectric devices.
Microstructure and Magnetic Properties of La-Doped Barium-Ferrite
Authors: Zhang Chang Sen , Yang Leia
Published: March 2013

The La-doped barium ferrites microparticles were successful synthesized by citrate sol-gel method. The structure, morphology and magnetic properties of the ferrite were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), differential thermal analysis (TG-DSC) and superconducting quantum interference device (SQUID). The results showed that the average crystallite size of La-doped barium-ferrite decreased with increasing La content. The morphology of the barium ferrite was spherical particles; however, doped lanthanum, barium ferrite changed into laminated structure. In addition, doping lanthanum improved the magnetic properties of the ferrite. The saturation magnetization (Ms) of La-doped M-type barium ferrite 67.70emu/g, it was greater than the non-doped M-type barium ferrite 57.45emu/g.
The Simulation of Soft Magnetic Materials’ Shielding Characteristic in the near Field Communication System
Authors: Zeng Yi , Yan Shuo Qing , Li Qi Fan , Feng Ze Kun , Wu Jie , Li Hui Wen , Peng Liang
Published: March 2013

A square coil antenna with a resonance frequency of 13.56MHz was proposed. Simulation analysis has been made to evaluate how the soft magnetic materials’ dimensions and the real part of permeability affect the shielding performance. The results show that the soft magnetic material with a larger or thicker dimension or with a higher real part of permeability has a better performance in shielding metals.
Electromagnetic Noise Suppression Characteristics of FeCoBM-Al2O3 Amorphous Soft Magnetic Films
Authors: Xiong Xuan , Feng Ze Kun , Wang Xian , Li Li Gong
Published: March 2013

The electromagnetic noise suppression characteristics of a series of FeCoBM -Al2O3 amorphous soft magnetic films were reported in the frequency range from 0.5GHz to 6 GHz. Effect of dopants on the reflection coefficient (S11), transmission coefficient (S21) and power loss (PLOSS/PIN) of as-deposited FeCoBM(M=Nb, Zr, Hf, Ta, Mo, Ti)-Al2O3 films were studied. The (Fe40Co40B20)89Mo8–(Al2O3)3 film had the highest power loss with the value of 0.85 at 6GHz. The transmission properties of the FeCoBNi-Al2O3 also studied in the paper. The power loss of the (Fe40Co40B20)68.36Ni28.64–(Al2O3)3 film was more than 0.6 from 3.0-6.0GHz, which had the best electromagnetic noise suppression characteristics. These results show that the presented films possesses potential in noise suppressor applied in electronic devices .
Influence of Microwave Calcination on Microstructure and Magnetic Properties of Sr-Hexagonal Ferrite
Authors: Chen Zhong Yan , Zhou Yuan , Chen Fu , Feng Ze Kun
Published: March 2013

The improvement of the microstructure of Sr-hexagonal ferrite and their magnetic properties by microwave calcined method was studied, the aim of the study was to obtain a fine grained microstructure in calcined stage. There was tendency to induce a large anisotropic during grain growth, microwave calcination method can succeed in obtaining homogeneous grain growth ,and help to reduce the calcination temperature and shorten the calcination time. The ferrites with saturation magnetization, remanent magnetization and intrinsic coercivity of 70.322emu/g, 36.182emu/g, 3343.1Oe, respectively, obtained in samples calcined at 1140°C for 30 min.
Influence of Si-Ca Oxide on Microstructure and Magnetic Properties of Calcined Sr1-xLaxFe2n-xCoxOα
Authors: Zhou Yuan , Chen Zhong Yan , Chen Fu , Feng Ze Kun
Published: March 2013

Calcined powders with the composition of Sr1-xLaxFe2n-xCoxOα (x=0-0.4) were investigated. The addition amount of Si or Ca oxide and combinations thereof were varied to analyze the effects on microstructure and magnetic properties of the calcined powders. It has been proved that there are interactions between the addition amount of Si-Ca oxide and La-Co oxide; what’s more, the right amount of Si-Ca additives can optimize the performance of the La-Co substituted calcined powders.
Effect of Surface Modified Foamed Fe Powder on Tribological Properties of Semi-Metallic Friction Material
Authors: Cao Yang , Zhou Yuan Kang , Wei Jian Yu , Yang Tao Yue , Nie Hua Wei
Published: March 2013

The silane coupling agent KH550 is used to modify foamed Fe powder(FFP) surface for obtain the hydrophobic surface, which is the very important component in semi-metallic friction material. It can improve high temperature bonding force between FFP and phenolic resin, further improve friction coefficient stableness of friction material and abrasion resistance. The modification effect of FFP is characterized by IR, and the tribological properties is characterized by XD-MSM constant speed friction test machine, the surface topography is characterized by SEM. The results indicate that FFP has been bonded to silane coupling agent, and formed hydrophobic surface what has the alkyl group. The changing of friction coefficient has reduced 23%, the average wear rate has declined 28.6%,and the wear rate has declined 32% at 350 °C after the friction material with modified FFP compare with the one with original FFP. And those changing are all because of the fact that the FFP modified by KH550 is difficult to peel off during the high temperature.
Effect of Duty Cycle on Microstructure and Corrosion Resistance of MAO Coatings Fabricated on AZ91D Magnesium Alloy in an Optimized Dual Electrolyte
Authors: Wang Shu Yan , Xia Yong Ping , Liu Li , Chen Qiao
Published: March 2013

Ceramic coatings were fabricated on AZ91D magnesium alloy in a novel optimized dual electrolyte by Microarc oxidation. The influence of duty cycle on coating thickness, surface roughness, phase composition, microstructure and corrosion resistance were studied. It is found that both the thickness and surface roughness of coatings increases gradually with the increasing of duty cycle. XRD results show that all the coatings are mainly composed of MgO, Mg2SiO4 and MgAl2O4. The results of potentiodynamic polarization tests indicate that the coating formed at 40% duty cycle exhibits a better corrosion resistance as a result of its relatively compact microstructure and more relative content of Mg2SiO4 and MgAl2O4 phases.
Investigation of the Microstructure Evolution of 6016 Aluminum Alloy during Homogenization
Authors: Yan Li Zhen , Zhang Yon Gan , Li Xi Wu , Li Zhi Hui , Wang Feng , Liu Hong Wei , Xiong Bai Qing
Published: March 2013

The microstructure evolution of automotive sheet 6016 aluminum alloy has been studied by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC) analysis. The as-cast microstructure was the typical dendritical structure, consisting of four phases: α-Al, β-AlFeSi, Mg2Si and Si. The electron diffraction analysis indicated that the β-AlFeSi phase was Al5FeSi. After 545°C for 20h homogenization treatment, Mg2Si and Si have been dissolved into matrix completely, and the remaining phase was β-Al5FeSi intermetallic compound. The transformation of β-AlFeSi→α-AlFeSi was not found during the homogenization process.
A Significant Improvement in Mechanical Properties of near Eutectic Nb-Si Alloys
Authors: Jiang Yong Jun
Published: March 2013

In this paper, a significant improvement in mechanical and oxidation properties of near eutectic Nb–Si alloys by the addition of aluminum (Al) and control of microstructural length scale were studied. A comparative study of two alloys Nb-18.79at%Si and Nb-12.3at%Si-9at%Al were carried out. Compression test yields the ultimate strength of 1.8±0.1 GPa and engineering strain of 2.3±0.03%. In comparison, the binary Nb-18.79 at% Si alloy possesses an ultimate strength of 1.35±0.1 GPa and strain of 0.2±0.01% when processed under identical conditions. The indentation fracture toughness of Al containing suction cast alloy shows a value of 20.2±0.5 MPa which represents a major improvement over bulk Nb–Si eutectic alloy
Multi-Objective Pareto Optimization of Double-Station Milling Process with the Use of PSO Algorithm
Authors: Lin Xian Kun , Wu Qian Qian , Xu Jian
Published: March 2013

In the paper,a new hybrid optimization technique for multi-objective optimization of surface milling is proposed. The developed approach is based on enhanced Pareto particle swarm optimization algorithm. The optimization of double-station milling is investigated basing on the available model in terms of two objectives: spindle power and production time. The final result is not a single solution but a whole set. In order to obtain satisfied Pareto set, multi-objective evolutionary algorithm for rail milling problem (MOEA-RMP) is used. An illustrative example was used to demonstrate effectiveness and applicability of the proposed approach.
The Performance Investigation of BaFe12O19-ZnFe2O4 which is a Composite Nano Powder
Authors: Feng Wang Jun , Fan Rui , Liu Hui Ling , Hui Peng Fei , Yang Hua
Published: March 2013

The nanoscale magnetic composite powders BaFe12O19-ZnFe2O4 were prepared by two-step citrate sol-gel, with analytically pure Fe(NO3)3、Zn(NO3)2 and Ba(NO3)2 as the main materials. The XRD, TEM and VSM were used to analyze the structure, feature and magnetic property of the nano-powder. The results show that the same presoma is calcined in 600°C、650°Cand 700°C obtained BaFe12O19-ZnFe2O4，XRD display for both pure phase, do not contain any mixed phase。The higher the temperature, the content of magnetoplumbite phase increased, corresponding the content of spinel phase low。By hysteresis loop of composite powde BaFe12O19- ZnFe2O4 can see, simple substance BaFe12O19 magnetoplumbite phase has the wasp waist shaped hysteresis loop，simple substance ZnFe2O4 spinel phase has superparamagnetism，but the nanoscale composite powders BaFe12O19-ZnFe2O4 has rectangular hysteresis loop。
Atmospheric Pressure Synthesis of ZnO Nanotubes by Aqueous Solution Route
Authors: Huang Jun , Lv Xiao Jing , Ouyang Mi , Hu Bin , Zhang Cheng
Published: March 2013

Single-crystalline ZnO nanotubes were fabricated via a simple aqueous solution method under low temperature and atmospheric pressure conditions. X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) equipped with the selected area electron diffraction (SAED) setup were used to analyze the crystal structure, surface morphology and inner structure of ZnO nanotubes. Photoluminescence (PL) and UV-visible absorption spectra were carried out to investigate optical properties of ZnO nanotubes. The results indicate ZnO nanotubes only exhibit sharp and strong near ultraviolet emission at 363 nm according to PL spectrum.
Study on the Preparation and Properties of Piezoelectric Glass-Ceramic Sr0.5Ba0.5Nb2O6
Authors: Jiang Shan , Lv Jing Wen , Zheng Tao
Published: March 2013

Series of ferroelectric glass-ceramic samples of Sr0.5Ba0.5Nb2O6 were synthesized by melting method. Firstly, analytical reagents were melted for 30 minutes at 1440°C after being grinded evenly according to a certain molar ratio, then annealed for 10 hours from 550°C to room temperature, finally it was sustained for 4 hours at constant temperature about 700°C. The hardness and transmittance parameters of SBN glass-ceramic were tested. Results indicated the sample had the best property when the amount of Nb2O5 was 10mol%, whose hardness reached 506 kg/mm2, and spectral transmittance was higher than 35% . XRD spectra of this sample indicated this SBN glass-ceramics contained a large number of Sr0.5Ba0.5Nb2O6 crystalline phase and a small amount of Sr0.3Ba0.7Nb2O6 phase. The particle size was about 50 nm.
AFM Characterization of PS Prepared in Different Concentration of Hydrofluoric Acid
Authors: Li Shao Yuan , Ma Wen Hui , Zhou Yang , Chen Xiu Hua , Ma Ming Yu , Xu Yao Hui , Xiao Yong Yin
Published: March 2013

The effect of HF concentration on the surface structure of porous silicon (PS) was carefully investigated by the AFM characterization. The results showed that no pores were present on PS surface which was prepared under the higher concentration of HF (10%). However, the pores were gradually visible with the HF concentration reduction. The main pores diameter was about 100 nm, when the concentration is 5.71%. The data of surface roughness and the main height distribution of the “hill” both showed an increase with the reduction of concentration, from 6.39 nm increase to 16.9 nm and from 30 nm increase to 90 nm, respectively, which implied that the pores were better exposed under the lower HF concentration.
Well-Defined Amphiphilic Polymer-Si(100) Hybrids via Surface-Initiated Atom Transfer Radical Polymerization
Authors: Peng Jin Wen , Mo Riu Hua , Liu Zhen Fan , Zhong Yuan Wei , Jie Qin , Deng Wei Xing
Published: March 2013

Well-defined amphiphilic graft polymer brushes containing fluoropolymer segments have been successfully prepared by (i) UV-induced coupling of 4-vinylbenzyl chloride (VBC) with the hydrogen-termined Si(100) (Si-VBC surface), (ii) surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxyethl methacrylate (HEMA) to produce the Si–VBC–g–P(HEMA) surface as the backbone of macroinitiator for further ATRPs, (iii) coupling of 2-bromoisobutyrl bromide with the HEMA polymer(P(HEMA)) by the esterification to produce the macroinitiators for the subsequent ATRP(Si–VBC–g–P(HEMA)-R3Br), (iv) surface-initiated ATRP of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) to produce the Si–VBC–g–P(HEMA)–g–P(HFBA) surface, and (v) the active P(HFBA) chain ends being used as the initiator for the subsequent ATRP of poly(ethylene glycol) monomethacrylate (PEGMA) to produce the amphiphilic Si–VBC–g–P(HEMA)–g–P(HFBA)–b–P(PEGMA) brush surface. The chemical composition and functionality of the silicon surface were characterised by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometry.
Characterization and Preparation of Glod Nanorods
Authors: Zhu Jun Yue , Jia Ling Xiang , Lin Ting Ting , Jiang Zhen , Tang Chao Wan , Tang Pei Song , Chen Hai Feng
Published: March 2013

Silver ions (Ag+) used as secondary ion, cetyl trimethyl ammonium bromide (CTAB) used as surfactant and ascorbic acid(AA) used as reducing agent, the gold(Au) nanorods were synthesized by seed-mediated growth method. The resulting substrates have been characterized by UV-vis spectroscopy. The law of Au nanorods growing was researched by controlling concentration of CTAB, Ag+, seed-fluid and AA. The results showed that the optimum reaction conditions are 0.10 M CTAB, 0.1×10-3 M Ag+, 0.0056×10-3 M AA, 0.48×10-6 M seed-fluid and system temperature 30°C.
Model Identification and Dynamic Performance Analysis of Fast Tool Servo System with High Frequency Response
Authors: Wen Ke Jie , Wang Gui Lin , Yang Fan
Published: March 2013

Fast tool servo system could achieve precise and efficient processing of fine micro-structure for its fast and accuracy response to input control signal, which will directly affect the processing quality of the workpiece surface. Different structural forms of fast tool servo system have been designed and presented in China and overseas, with which generally low the stiffness and natural frequency, only can be used for the rule and the characteristic scale of the larger surface processing. A fast tool servo system whose thrust was up to 12500N, stiffness was 280N/μm, the natural frequency was more than 3kHz , was developed in this paper, as well as the analytical expression of time domain and frequency domain output，which were presented by the modeling analysis; The unknown parameters of the system model were identified by frequency response test. The theoretical and experimental results indicated that the system has good dynamic performance to meet the fine micro-structure of highly efficient, high-precision processing needs.
Finite Element Analysis Route to Achieve Accurate Resistivity Measurements in Diamond Anvil Cell
Authors: Nan Xuan Guo , Peng Gang , Wu Bao Jia
Published: March 2013

To have a clear understanding of the effect of electrode resistivity on the in-situ resistivity measurement under high pressure in a diamond anvil cell (DAC), we perform finite element analysis (FEA) to simulate the distribution of the steady current field in sample. The theoretical analysis reveals the origin of the effect. It is caused by the resistivity difference between electrodes and sample. And the more the difference of their resistivity is, the more obvious the effect is. All these will result in large resistivity error. However we find that reducing the resistivity difference between the electrode and sample can improve the results.
Spectral Features of Zn1-xMgxO Thin Films Synthesized by the Sol-Gel Route
Authors: Xian Feng Lin , Li Xiang Yin
Published: March 2013

Zn1-xMgxO (x=0, 0.05, 0.1, 0.2 and 0.3, respectively) thin films have been synthesized by sol-gel method on glass substrates. The structure, morphology and optical properties of the samples have been studied by X-ray diffractonmeter (XRD), scanning probe microscope, UV-visible spectrophotometer, fluorescence spectrophotometer and spectroscopic ellipsometer, respectively. The XRD result shows that all the films have hexagonal wurtzite structure; no phase segregation is observed. The surfaces of Zn1-xMgxO thin films are smooth and the root mean square (RMS) roughness of the samples is only several nanometers. The transmittance spectra reveal that all samples have high transmittance above 90%, with Mg doping content increase, the optical band gap increases from 3.27eV to 3.77eV. The photoluminescence spectra show that all samples have two emission peaks in ultraviolet and violet region, a blue shift of ultraviolet emission is observed. The refractive indexes of all samples decrease with the increase of wavelength ranging from 350nm to 900nm. The refractive index changes apparently by varying Mg content, which has potential application in research of optical materials and the design of optical devices.
Study on Magnetic Mn0.2Co0.8Fe2O4/Silicalite-2 Catalyst and its Electro-Catalytic Property
Authors: Cheng Yue , Pan Shun Long , Zhou Yuan
Published: March 2013

Silicalite-2 zeolite was hydrothermally synthesized and Mn0.2Co0.8Fe2O4 magnetic nano-particle based on the Silicalite-2 zeolite carrier was prepared by a coprecipitation-impregnation method. The morphologies and microstructures of synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The heterogeneous catalytic oxidation electrolysis system of Mn0.2Co0.8Fe2O4/silicalite-2 was built by dispersing the catalysts in glass reactor for treating cationic brilliant red X-5GN wastewater. The SEM images showed that the structure of silicalite-2 zeolite remained its original after the introduction of Mn0.2Co0.8Fe2O4 magnetic particle. The XRD patterns revealed that Mn0.2Co0.8Fe2O4 oxides could not be observed on the surface of the silicalite-2 zeolite carrier. The experimental results showed that the dye wastewater with a satisfied decolorization rate (79.1%) was obtained when the initial pH was 6, the magnetic catalyst dosage was 0.4g/L, the electrolysis voltage was 2V, electrolytic time was 45min, respectively.
A Simple, Green Synthesis of Photochromic, Monoclinic Tungsten Oxide Fiber
Authors: Xu Ying Ming , Cheng Xiao Li , Huo Li Hua , Zhao Hui , Gao Shan , Bai Xiao Hui , Ding Jian , Wang Zhi
Published: March 2013

The fiber shaped monoclinic tungsten oxides with high preferential orientation has been synthesized by dialysis and aging treatment at room temperature, of the white precipitates prepared from HCl acidified (NH4)10W12O41 solution. The microstructure evolution of the above tungsten oxide was studied by SEM. The morphology of the powder changed from irregularity to shuttle plate-like during short time dialysis in pure water, and the butterfly shape was obtained after long time treatment. It was found that the nano-particles were rearranged to form nano-fibers on the surface of the butterfly shaped oxide as a function of aging time when the butterfly powder was kept in the original mother liquor. Compared to butterfly oxide, the morphology of fibers exhibited much improved thermal stability. The photochromic property of the tungsten oxide with different morphology was studied. The response time in color change after irradiated by the UV output of a 30 W mercury lamp is 20 s in inert atmosphere and the recovery time in bleach is about 2 months.
Oxidative Damage of Brain Induced by Nano-CdSeS in Mice
Authors: Yang Shang Yue , Ye Ran Feng , Cai Wen Jun , Xiang Xiao Ling , Yang Xu
Published: March 2013

In this experiment, the oxidative damage of nano-CdSeS in mice brains was performed. 20 male Kunming mice were divided into 4 groups and 3 experimental groups were exposed to different doses of nano-CdSeS (0.1 mg/mL, 0.2 mg/mL and 0.4 mg/mL) by intravenous administration while the control used saline solution instead. Three days later, the enzymatic activity of superoxide dismutase (SOD), the content of malondialdehyde (MDA) and the damage degree of DNA were determined to assess the oxidative damage in brain tissues. Our results showed that in the experimental groups, SOD activity was inhibited and MDA content was increased as the doses rising, at the same time, tail moment and tail DNA% increased significantly when comparing with the control. And these results exhibited a certain doses-dependency relations. From results above, it demonstrated that oxidative damage of brain induced by nano-CdSeS which enter into blood–brain barrier in mice.
Study on Micro-Nano Sensor System in Structure Vibration Safety Monitoring of Large Span Bridge
Authors: Yang Yaoen , Sun Xing Cheng , Wang Qing Min
Published: March 2013

The conventional sensor in bridge structure vibration monitoring field has such disadvantages as high price and poor long-term stability. According to this insufficient, a kind of novel MEMS sensor micro system, which can be used to real-time monitor the structure vibration of large span bridge, is developed. For such system, the sensing element structure of 3D-MEMS is designed. The theoretical model of sensing test is established. And the three level packages, which are chip level, device level and micro-system level, is completed. The data acquisition system based on this sensor is developed. And this kind of sensor system has been applied to the structure health monitoring of the Yellow River bridge of Zhengzhou and the Yangtze River bridge of Wuhan to measure the horizontal, vertical vibration and acceleration signals. The measuring results show that this sensor micro-system has such advantages as good long-term stability, strong anti-interference ability, and high test sensitivity up to 2V/g. As it is simple, this test system can greatly reduce the testing cost.
One-Step Preparation of Polypyrrole Nanoparticles by a Reactive-Template Method
Authors: Yao Tong Jie , Wu Jie , Cui Fang , Sun Ke Ning , Cui Tie Yu
Published: March 2013

Polypyrrole nanoparticles (PPy NPs) were successfully prepared in one-step by a reactive-template method. Fe3O4 NPs were selected as the reactive-template, and they acted as both templates to shape structure of PPy NPs and initiator source, simultaneously. No surfactants were used in whole process, which dramatically improved the purity of resulting products. HCl solution concentrations played an important role on the morphologies of resulting PPy NPs.
Influences of Re-Sintering on the Structure and Electrochemical Performance of LiNi1/3Co1/3Mn1/3O2
Authors: Yuan Li , Zhang Yun , Liu Wen Jing , Wang Fu , Lu Chao
Published: March 2013

The influences of re-sintering on the structure and electrochemical performance of LiNi1/3Co1/3Mn1/3O2 were researched in this paper. The synthesized materials were characterized and tested by means of X-ray diffraction (XRD) and electrochemical measurements respectively. It was found that the re-sintered samples with better well-ordered layered structure, more perfect crystallization and more complete crystal structure will be formed with increasing temperature. Moreover, reasonable re-sintering time was required. The materials re-sintered at 860°C for 2h exhibited the best electrochemical performance, including high initial discharge capacity of 150.6 mAh•g-1 and coulomb efficiency of 84% at 0.2C rate.
The Effect of Double-Element Doping on the Photocatalytic Property of Nano-TiO2
Authors: Huang Su , Li Fu Yun , Li Yang , Yang Li Zhen
Published: March 2013

Sol-gel method was applied to synthesize nano-TiO2 particles doped with metal and non-metallic elements. Nano-TiO2 particles were doped at different calcinations’ temperatures with S and Fe, Ce and La, respectively. A comparison was performed on the effect of different metallic elements on nano-TiO2 particles doped with the same non-metallic element S. X-ray diffraction results indicated that the diameter of doped nano-TiO2 particle was smaller than that of non-doped nano-TiO2 particles. The minimum diameter of nano-TiO2 doped with Ce and S was about 8nm, while that of nano-TiO2 doped with La and S was about 9nm. The minimum diameter of nano-TiO2 particles doped with Fe and S was about 10nm. In addition, with the increase of calcinations’ temperature, the size of nano-TiO2 particle increased. All nano-TiO2 particles doped with double elements were antae. Methyl orange was used to simulate the pollutant to analyze the photocatalytic property of doped nano-TiO2. The results indicated that the doped element had some effect on the photocatalytic property of nano-TiO2, and varied for different doped metallic elements. Among them, the degradation rate of methyl orange by nano-TiO2 doped with La and S under the calcinations’ temperature of 550 °C reached 28.97%.
Structural and Magnetic Properties of Ho3Fe29-xTx (T=V and Cr) Compounds
Authors: Han Y.N. , Han X.F. , Liu H.L.
Published: March 2013

The crystallographic structural characteristics and magnetic properties of Ho3Fe29-xTx (T=V and Cr) compounds have been investigated by using Rietveld refinement analysis of X-ray diffraction (XRD) pattern and magnetic measurements. The calculated results indicate that among the 11 different kinds of Fe sites in these Ho-Fe compounds the preferential sites of the stabilizing elements V and Cr are quite different. The refined lattice parameters of these compounds are in good agreement with the experimental data. Spin reorientations of easy magnetization direction (EMD) are observed at around 150 K for Ho3Fe27V2 and Ho3Fe25.5Cr3.5. At the around 1.7 T critical fields (HCR) first order magnetization process (FOMP) occurs in magnetization curves at 4.2 K for the magnetically aligned samples of Ho3Fe27V2 and Ho3Fe25.5Cr3.5.
Friction Coefficient of Nano-Ceramic Polished by Oxide Film on ELID Grinding Wheel
Authors: Kuai Ji Cai
Published: March 2013

The dynamic changes of the friction properties of the oxide film are characterized by the dynamic changes of the ELID grinding force. The tangential force and normal force are used to represent the friction coefficient in order to obtain the accurate real-time friction coefficient of oxide film. Therefore, the friction coefficient of various grinding wheels with different bonding agents, various grinding parameters, various grinding materials (nano- Al2O3 ceramic, nano ZrO2 ceramic and ordinary ZrO2 ceramic), and ELID grinding and ordinary grinding can be further studied. The results show that: the friction coefficient of the oxide film on the bronze-based grinding wheel is greater than that composed by iron; the friction coefficient of the oxide film decreases with the increase in grinding depth and feeding speed; the friction coefficient of the oxide film and nano-materials is smaller than that of the oxide film and ordinary materials; the transformation from γ-Fe2O3 to α-Fe2O3 in oxide film and the elastic deformation of the oxide film caused by the high-temperature of grinding may make the friction coefficient of ELID grinding greater than that of ordinary grinding, so the oxide film contains better property of friction and polishing. Therefore, excellent surface quality is easier to be obtained by it compared with the ordinary grinding technology.
Thin Film Nanofibrous Composite Ultrafiltration Membrane for Oil Removal from Oilfield Wastewater
Authors: Li Xiong , Wang Li Li , Yang Yin , You Hao , Zhang Wen Cun , Qin Xiao Huan , Wang Xue Fen
Published: March 2013

Nanofibrous substrate composite ultrafiltration membrane consisted of polyacrylonitrile (PAN) electrospun scaffold which was used as the substrate, and a thin crosslinked poly(vinyl alcohol) (PVA) barrier layer which was prepared by electrospinning technique combined with mixed solvent treatment. The thickness of PVA nanofibrous top layer was controlled by changing the electrospun depositing time. Through immersing PVA/PAN double-layer mats into water/acetone mixed solvent system, the PVA nanofibrous top layer was swollen to merge imperceptibly into an integrated barrier film on the surface of PAN substrate, and then chemically crosslinked by glutaraldehyde. The resultant PVA/PAN thin film nanofibrous composite (TFNC) membrane has high rejection rate (99.6%), high flux (410.5l/m2h) and good anti-fouling characteristic at very low operation pressure (0.2MPa) for separating oil from the oilfield wastewater. Additionally, the removal of TDS, suspended matter, total iron and sulfate reducing bacteria (SRB) showed high rejection rate with relatively stable PH.
Research on Process Parameters of Ballscrew Manufactured by Cold Rolling
Authors: Cui F.K. , Wang X.Q. , He X.J. , Li Y. , Han Z.R.
Published: March 2013

To optimize the process parameters of cold rolling the finite element model of metal plastic flow in cold rolling was carried out based on the cold forming principle of ballscrew and rigid-plastic finite element theory. The adaptive mesh refinement was utilized to improve calculation accuracy in large plastic deformation zone. Using lagrangian algorithm the processing of cold rolling is numerically simulated by DEFORM-3D. The appropriate revolution speed is got by analyzing different simulation results such as the maximum stress and maximum strain and flow velocity etc. under different revolution speeds. The appropriate transmission ratio is got by analyzing different simulation results such as the maximum stress and maximum strain and flow velocity etc. under different transmission ratios. The research results provide evidence for process parameters optimization. At the same time those research results lay a foundation of further study of forming mechanism.
Study on Automatic Hydrological Telemetry System Based on SMS/GPRS
Authors: Wang X.J. , Fu X.G. , Zhou M.X.
Published: March 2013

According to the practical situation in hydrological telemetry stations, a perfect solution scheme based on GPRS/GSM wireless network is made. The reliability and timeliness of data transmission is assured in maximum extent by GPRS and auxiliary SMS. By using the automatic hydrological telemetry system, the traditional manual way is thoroughly discard and the work intensity of prediction is greatly decreased. Integration of telemetry, forecasting and monitoring is really realized.
Off-Axis Aberration Measurement Based on the Hartmann-Shack Sensor
Authors: Xu A.C. , Chen J.B. , Zhang P.M. , Wu J.J.
Published: March 2013

Human eyes is an imperfect imaging system that has various aberrations such as on axis and off axis aberrations, which often affect the imaging quality of retina. However, the available aberration methods are mainly concerned with on-axis aberration measurement, which include defocusing, astigmation, and some higher order aberration measurements. Therefore, off-axis aberration measurement under the principle of Hartmann-Shack sensor is proposed in this paper with an empirical study, the results of which showed that the imaging quality of human eyes’ peripheral field decreased with the enlargement of off axis angle. The enlargement of human eyes’ off axis aberration and the decrease of photosensory cell density of the peripheral field are two reasons for such a result.
Reflection and Refraction of Coupled Transverse and Micro-Rotational Wave at Interface between Two Micropolar Elastic Solid
Authors: Xu Hong Yu , Xue B.B. , Cui F.K. , Wang X.Q.
Published: March 2013

Using the model of micropolar generalized magneto-thermo-elasticity, the coupled transverse and micro-rotational wave at an interface between two micropolar solid mediums is discussed in the presence of a constant magnetic field. The model can be applied to the coupled theory as well as to five generalizations: the Lord-Shulman theory with one relaxation time, the Green-Lindsay theory with two relaxation times, the Green-Naghdi theories of type II(without energy dissipation) and of type III, and the theory with dual-phase-lag. Using continuous conditions at the interface, the amplitude ratios of reflected and refracted longitudinal displacement waves, longitudinal micro-rotational waves and the coupled transverse and micro-rotational waves are studied for incident coupled transverse and micro-rotational wave. The effect of thermal relaxation is discussed for C-D theory, G-L theory and L-S theory. The numerical results show that the effects of thermal relaxation times are very significant on the amplitude ratios.
Vacuum Casting Bubble Automatic Elimination System Based on on-Line Machine Vision Detection
Authors: Liu Y.Y. , Chi Z.F. , Hu Q.X. , Yao Y. , Huang J.
Published: March 2013

Bubbles in vacuum casting process are dense, tiny and overlapped. The difference between bubbles and the background is so indistinct that makes bubble detection a great difficulty. Bubble elimination has become the main obstacle in the way of vacuum casting machine’s automation development. Bubble automatic detection is the base of bubble elimination. A machine vision bubble on-line detecting and eliminating platform is constructed, using industrial high-speed CCD camera and professional LED illumination. According to the features of vacuum casting bubbles, the edge pixel ratio algorithm is designed especially for vacuum casting bubble detection. The algorithm is realized using VC++ and Open CV. The integrated system proposed can detect and eliminate vacuum casting bubbles on-line automatically. As it’s confirmed, there is an obviously positive correlation between the edge pixel ratio and the bubble denseness. This detection system makes sense in vacuum casting bubble elimination.
Stability Analysis on Milling Processing of Aviation Aluminum Alloy
Authors: Wu Wei Hua , Guo Y.Y. , Zhao C.
Published: March 2013

Based on milling experiment to explore the transformation and stress condition in the process of cutting of the thin-wall part made by aviation aluminum alloy, and then get data from the milling experiment through altering the axial cutting depth Ap=1 mm (a=1 mm), cutting radius Ae, spindle speed n and feed per tooth for milling force fz. Considering the milling force coefficient affected by each milling parameters, the orthogonal experiment of four factors and four levels are designed, and the milling coefficient is solved by MATLAB. The results indicates that the axial cutting depth Ap=1 mm (a=1 mm), the cutting force Fx increases with increasing in feedrate per tooth fz (c). the feedrate per tooth fz=0.03 mm (c=0.03 mm), the cutting force Fx increases with increasing in the axial cutting depth Ap. The discipline that the milling coefficient has an influence on milling force is obtained from the research which can provide the reference on the purpose of optimizing milling coefficient.
Experiment Research of Cutter Edge and Cutting Parameters Influence on Machined Surface Roughness for High Speed Milling Hardened Steel
Authors: Zhang Wei , Zheng M.L. , Cheng M.M. , Wang W.T.
Published: March 2013

By using experiment cutter edge topography obtained by super depth three-dimension microscope, fits the cutter edge curve and calculate experiment cutter edge radius value; by high speed milling hardened steel experiment, individually researches cutter edge and cutting parameters influence on machined surface in high speed milling hardened steel with end-milling cutter and ball-end milling cutter. The experiment analysis results show that under the same cutting parameters condition, machined surface roughness in high speed end-milling cutter milling is better than in high speed ball-end milling; within experiment selected cutting parameter range, cutter edge radius is the main influence factor on machined surface roughness in high speed end- milling hardened steel, while the influence on machined surface roughness in high speed ball-end milling hardened steel is not obvious. In end-milling, when edge radius and milling depth are in the same order magnitude or the difference is not obvious, milling depth should be a little bigger than selected cutter edge radius value.