bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiment Study of Heat Transfer in Aeroengine Bearing Chambers
Authors: Yuan Xi Chuan , Guo Hui , Wang Liang Yun
Published: August 2011

In this paper, a method of heat transfer test research in aeroengine bearing chamber has been introduced. The method attains the law of heat transfer in bearing chamber and the influence of heat transfer coefficient on bearing dn value, oil flow, supply oil temperature, sealing air flow by simulating the oil work condition in turboshaft engine typical high temperature bearing chamber.
A Model of Nonlinear Dynamic Modeling for Planetary Gear Transmission System with Backlash
Authors: Li Fa Jia , Zhu Ru Peng , Bao He Yun , Li Xiao Zhen
Published: August 2011

The (4+N) DOFs (degrees of freedom) nonlinear dynamic model of the planetary gear transmission system has been established which include the horizontal displacement, vertical displacement of sun gear, eccentricity error excitation of the sun gear and planetary gear, and gear backlash. The nonlinear dynamic equations was dealt with non-dimensional. Non-dimensional relative displacement of sun gear with planet gears and planet gears with internal gear were solved by using the method of numerical integration. Load sharing coefficients of every planet gear was got by dealt with the result of dynamic equations. The differences of non-dimensional relative displacement and load sharing coefficient were contrasted.
Effects of Gear Manufacturing Error on the Dynamic Characteristics of Planetary Gear Transmission System of Wind Turbine
Authors: Chen Hui Tao , Wu Xiao Ling , Qin Da Tong , Yang Jun , Zhou Zhi Gang
Published: August 2011

The effects of gear manufacturing error on the dynamic characteristics of planetary gear transmission system of wind turbine are studied in this paper. Firstly, the static transmission error combined with manufacturing error of the gear is deduced. Then, the nonlinear dynamic model of planetary gear transmission system of wind turbine is set up with the consideration of time-varying mesh stiffness, backlash and manufacturing error. Finally, the statistical characteristics of Vibration displacement response process of each component of planetary gear transmission system are obtained by simulation analysis of the planetary gear system of 1.5MW Semi-direct drive wind turbine with the consideration of the torque fluctuation caused by wind speed. The research results lay a foundation for reliability design and optimizing of gear transmission system of wind turbine.
Dynamic Contact Emulate Analysis of Logarithmic Spiral Bevel Gear with ANSYS/LS-DYNA
Authors: Li Qiang , Wu Shu Qin , Yan Hong Bo
Published: August 2011

For a new type of bevel gear-logarithmic spiral bevel gear, which stress mechanical properties are studied during the meshing process. Three-dimensional meshing models of logarithmic spiral bevel gear are established by Pro/ E. Because its tooth trace is conical logarithmic spiral, the paper proposes a new modeling method and successfully constructs the engagement model. Based on this, the gear dynamic contact emulation analysis is operated with ANSYS/LS-DYNA software in order to obtain stress distribution in the process of tooth contact. The tooth contact stress and tooth root bending stress magnitude, stress distribution and variation of cloud are analyzed. Contacting engineering practice, the results are in-depth study. Thus it can provide the theory basis for design and the application of this kind of new bevel gear.
Application Probing of Advanced Helicopter Transmission System Technology
Authors: Ding Wen Qiang
Published: August 2011

This paper performs analyses and studies to a part of the foreign advanced helicopter transmission system technology. It introduces the design train of thought, main component structures and relevant parameters. It will give a reference to engineering technical personnel of the helicopter transmission system.
Study on Dynamic Characteristics of Wind Turbine Planetary Gear System Coupled with Bearing at Varying Wind Speed
Authors: Zhou Zhi Gang , Qin Da Tong , Yang Jun , Chen Hui Tao
Published: August 2011

The sparse least squares support vector machines (SL-SVM) is used to simulate wind speed of real wind field, and time-varying wind load caused by stochastic wind speed is then obtained. A coupling gear-bearing dynamical model of planetary gear transmission system of wind turbine is built using lumped-parameter method, in which the varying wind load, time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing are taken into account. Numerical method is used to simulate the dynamic performance of planetary gear transmission of multibrid technology wind turbine (MTWT) with 1.5MW rated power, the vibration displacement responses of gears and dynamic meshing forces of gear pairs as well as nonlinear bearing forces in the transmission system are obtained, and the influence rules of external varying wind load on the vibration characteristics of transmission system of wind turbine are studied. The research results lay a foundation for dynamic performance optimization and reliability design of gear transmission system of wind turbine.
Optimum Design of Motion Curve of Cam Mechanism with Lowest Maximum Acceleration
Authors: Sun Chuan Qiong , Ren Ai Hua , Sun Guo Xing
Published: August 2011

Taking case of 4500kN automatic multi-station cold forming machine clamp cam design, the mathematical model of motion curve with lowest maximum acceleration of disk cam with oscillation follower is set up on the basis of failure analysis and optimum design is carried out .A modern design method of cam motion curve is proposed in this research.
Study of Load Distribution and Sharing Characteristics of Planetary Geartrain for Wind Turbines
Authors: Kim Jeong Gil , Lee Geun Ho , Park Young Jun , Nam Yong Yun , Chong Tae Hyong
Published: August 2011

Most wind turbine gearboxes and pitch/yaw reducers consist of several planetary geartrains. Planetary geartrains allow gearboxes to be small, light, low noise, and efficient. The most important factors in the planetary geartrain design are load sharing among the planet gears and load distribution on the gear tooth flank. This study was conducted to analyze the load sharing and distribution in reducers with and without a slewing bearing. Load sharing and distribution of a pitch reducer without a slewing bearing were very uniform and even. However, in the other case, they were non-uniform and uneven, and the gear meshes were formed on the right or left. These results show that heavy loads act on the right or left flank of a meshed gear pair and reduce the gear life. Therefore, the slewing bearing must be considered when pitch/yaw reducers are designed and analyzed.
Asymmetric Gears: Parameter Selection Approach
Authors: Kapelevich Alexander
Published: August 2011

In many gear transmissions the tooth load on one flank is significantly higher and is applied for longer periods of time than for the opposite one. An asymmetric tooth shape reflects this functional difference. This paper describes an approach to rationalize the asymmetric gears parameter selection to meet a variety of operating conditions and requirements to custom high performance gear drives.
Structural Design and Analysis of Thrust Collar in Main Wind Turbine Speed-Increasing Gearboxes
Authors: Xiang Qing Qi , Li Min , Zhang Yue Chun , Zhou Hong Bo
Published: August 2011

Analysis has been made on the structure of thrust collar adaptedin main wind turbine gearboxes and a new design method for the thrust collar has been proposed. In addition, we presented a model of thrust collar which allows us to compute the stress distribution. It is showed that the design method is a practical one in thrust collar project of the main wind turbine gearboxes.
Micropitting in Wind Turbine Gearboxes: Calculation of the Safety Factor and Optimization of the Gear Geometry
Authors: Dinner Hanspeter
Published: August 2011

If the contact pressure between mating flanks of a gear set is increased, the lubricant film thickness in between is reduced to a level where the asperities of the flanks start to touch. This case where the surface roughness is of similar value as the EHD film thickness is called “mixed friction”. Due to the metallic contact of the asperities and the movement of the flanks with respect to each other, the flanks are damaged. The damaged flanks appear dull or greyish, hence the name “grey-staining” (or “Graufleckigkeit” in German), see e.g. [4] or [1]. Micropitting are small cracks on the surface of the gears (as opposed to pitting, where the cracks form below the surface), which grow into the material. The size of the damages is about 10-20 mm depth, 25-100 mm length and 10-20 mm width. Micropitting is mainly observed with case carburized gears but may also be found in nitrided, induction hardened or through hardened gears. Micropitting mainly occurs in areas of negative specific sliding. Negative specific sliding is to be found along the path of contact between point A and C on the driving gear and between point C and E on the driven gear.
A New Information Entropy-Based Ant Clustering Algorithm
Authors: Zhao Wei Li , Zhang Zhi Guo , Zhang Zhi Jun
Published: August 2011

Ant-based clustering is a heuristic clustering method that draws its inspiration from the behavior of ants in nature. We revisit these methods in the context of a concrete application and introduce some modifications that yield significant improvements in terms of both quality and efficiency. In this paper, we propose a New Information Entropy-based Ant Clustering (NIEAC) algorithm. Firstly, we apply new information entropy to model behaviors of agents, such as picking up and dropping objects. The new entropy function led to better quality clusters than non-entropy functions. Secondly, we introduce a number of modifications that improve the quality of the clustering solutions generated by the algorithm. We have made some experiments on real data sets and synthetic data sets. The results demonstrate that our algorithm has superiority in misclassification error rate and runtime over the classical algorithm.
Mechanical Properties of Several NiTi Alloy Wires in Three-Point Bending Tests
Authors: Dechkunakorn Surachai , Isarapatanapong Rutchadakorn , Anuwongnukroh Niwat , Chiranavanit Nattiree , Kajorchaiyakul Julathep , Khantachawana Anak
Published: August 2011

Objective: To clarify mechanical properties of 14 superelastic NiTi orthodontic wires by three-point bending tests. Materials and Methods: The three-point bending test was conducted with a midspan deflection rate of 5 mm/min under constant temperature range 36±1°C. Wires were deflected to 3.1 mm. All data were recorded during the unloading process at deflections 3, 2, 1 and 0.5 mm. to simulate the force a wire exerts as a tooth is moved into the dental arch from a position of malocclusion. Results: The delivered forces changed slightly when the deflection varied during loading and unloading. Sentalloy wire applied the lowest continuous force. Conclusions: Commercial wires may not behave similarly due to minor differences in the production process, and force varies greatly from brand to brand. NiTi wire brands must be selected carefully considering the severity of malocclusion and stage of orthodontic treatment.
Modelling of Unilateral Contact of Metal and Fiberglass Shells
Authors: Karash Emad Toma
Published: August 2011

In this work the variant of calculation of two coaxial shells of rotation in the form of sphere from a material is offered, corresponding which surfaces are located from each other on the set distance. At action of internal pressure on local sites between shells there is a unilateral contact. Distribution of contact pressure on length of sites of contact is with the account transversal pressure considered shells on a thickness.
Development of Cutting Force Model of Aluminum Nitride Ceramic Processed by Micro End Milling
Authors: Reddy Moola Mohan , Gorin Alexander , Abou-El-Hossein Khaled A.
Published: August 2011

Advanced ceramics are difficult to do machining due to brittle nature. High cutting forces will generate in the machining, which will affect the surface integrity of final product. Selection of proper machining parameters is important to obtain less cutting force. The present work deals with the study and development of a cutting force prediction model in end milling operation of Aluminum Nitride ceramic. The cutting force equation developed using Response Surface Methodology (RSM) to analyze the effect of Spindle speed, feed rate and axial depth of cut. The cutting tests were carried under dry condition using two flute square end micro grain carbide end mills.
Multiobjective Optimization of Hybrid Electrical Vehicle Powertrain Mounting System Using Hybrid Genetic Algorithm
Authors: He Jian Feng , Jin Xiao Xiong
Published: August 2011

Powertrain mounting system of a Hybrid Electrical Vehicle (HEV) is analyzed and researched, the expression of energy distribution matrix and that of mounting reaction force are derived, and mathematical model of the system is established in Matlab. Correctness of the model established is tested and verified through model establishing for simulation and calculation in ADAMS. Features of Hybrid Genetic Algorithm (HGA) for multiobjective optimization are analyzed and researched, model for calculation of multiobjective optimization using Hybrid Genetic Algorithm is established, targets for optimization of the system are determined, and optimization is executed based on the mounting stiffness parameters. The result that the system is optimized apparently by Hybrid Genetic Algorithm is revealed through contrast of the energy distribution matrix and mounting reaction force of pre and post-optimization.
Research on Enzymatic Hydrolysis Lignin Modified Petroleum Asphalt
Authors: Zhao Zhi Dong , Xie Yao , Cheng Xian Su , Jin Yan Qiao , Xu Ming Yang
Published: August 2011

In this paper, a series of enzymatic hydrolysis lignin modified petroleum asphalts were prepared. The physical properties such as softening point, ductility at low temperature and penetration of the modified asphalt were investigated. The penetration index of asphalt modified with EHL was higher than that of unmodified asphalt, equivalent softening point increased and equivalent brittle point decreased with the increase of EHL amount, which showed that the addition of EHL was favorable to reduce the temperature susceptivity of asphalt. When the EHL was 4%, the ductility was 39.0 cm. Meanwhile, low temperature performance of asphalt could be further improved by adding EHL and a small amount of SBS.
Influence of Limestone Powder on Performance of the Pre-Mixed Cement Mortar
Authors: Zhang Xiu Zhi , Han Chao Shun , Yin Xue
Published: August 2011

Effect of the different contents of limestone power (LSP) in manufactured-sand (MS) is investigated in respect of the workability, setting time and compressive strength. The results show that the contents in a certain range can significantly increase the consistency, Specific density of the fresh mortar, and improve comprehensive strength of the hardened mortar due to LSP deduced the porosity and improved the pore structure.
Conductometric Study of the Effect of Citric Acid on Phase Evolution of Calcium Phosphate in Solutions
Authors: Li Cheng Feng , Ge Xiao Lu , Bai Jia Hai , Li Guo Chang
Published: August 2011

The influence of citric acid on phase evolution of calcium phosphate is studied by the electrical conductivity of reaction solutions. The conductance curves are divided into three distinct regions and assigned to the formation of amorphous calcium phosphate (ACP), hydroxyapatite (HA) and the solubility of HA, respectively. When more citric acid is added, the width of region I decreases because moreCa2+ions would prefer to foster the nucleation of HA from ACP. Decreasing rate of conductivity in region II becomes smaller with more addition of citric acid because the supersaturation of HA decreases in solutions. And thus, HA powders with larger grain size are synthesized with more citric acid addition.
Facile Synthesis of Cobalt Oxide Uniformly Coated on Multi-Wall Carbon Nanotubes for Supercapacitors
Authors: Gong Liang Yu , Su Ling Hao
Published: August 2011

The composite electrodes of cobalt oxide and multi-wall carbon nanotubes (MWCNTs) are prepared by a simple low-temperature solid-phase synthesis method with the assistance of polyethylene glycol and their pseudocapacitive performances are investigated in alkaline solution by cyclic voltammetry and galvanostatic charge/discharge tests, respectively. Transmission electron microscope images show that cobalt oxide is uniformly coated on multi-wall carbon nanotubes and the homogeneous hybrid nanostructure are considered to be responsible for their preferable electrochemical performances. The electrochemical tests further reveal that the composite can deliver a maximum specific capacitance of 217 F/g with a biggest utilization of Co element when the content of MWCNTs increases to 50 wt.%.
Influence of Doping Methods on the Gas-Sensing Properties of CuO-SnO2 Sensors
Authors: Lin Zhi Dong , Song Wen Long , Yang Han Min , Zheng Ju Cheng
Published: August 2011

Nano crystalline SnO2was prepared by sol-gel with PEG surfactant. CuO was doped in the SnO2by mechanical mixture and reaction congelation from CuCl. The samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption isotherms (BET). The results indicated that the average crystal size of SnO2 at sintering temperature of 550 °C was 10 nm, the conglomeration size of SnO2was about 100 nm. The specific surface area of pure SnO2, mechanical doping SnO2and reaction doping SnO2were 110, 84, 72 m2/g, respectively. The thick film gas sensors made from these samples were examined. SnO2doped by different methods had different electrical and gas-sensing properties. The sensors based on CuO doped SnO2films exhibited less sensitive to ethanol gas but extremely higher sensitivity to H2S gas than that of pure SnO2.
Facile Preparation of NiO/Ni Nanocomposite and its Electrochemical Capacitive Behaviors
Authors: Yin Wei Dong , Li Gui Lian , Liu Xian Ming
Published: August 2011

NiO/Ni nanocomposites were prepared by chemically reduction-oxidation process in tetra-ethylene glycol (TEG) solution. The structure and morphology of the samples were examined by XRD and SEM. The results indicated the composite consisted of NiO and Ni and exhibited spherical morphology with diameter of 50-200 nm. The electrochemical performances of composite electrodes used in electrochemical capacitors were studied. The electrochemical measurements were carried out using cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy in 6M KOH aqueous electrolyte using three-electrode Swagelok systems. The results showed that the composite had a high specific capacitance and excellent capacitive behavior. The specific capacitance of the composite decreased to 192F/g after 500 cycles. Due to the existance of Ni, the charge transfer resistance is lower than 1Ω. It revealed that the composite exhibited good cycling performance.
A Strategy to Produce Single and Double Layer Graphene Sheets
Authors: Dhakate S.R. , Chauhan N. , Sharma S. , Mathur R.B.
Published: August 2011

We report an easy and scaleable approach to produce single and double layer graphene (Gr)-sheet from re-exfoliation of expanded graphite (EG) with large area. Transmission and scanning electron microscopic observations show that the Gr-sheets have an area of ~ (12 x 10) μm2. Raman spectroscopy has confirmed the presence of single and double layer Gr-sheet with I2D/IG ratio as ~ 1.7. Scanning probe microscopy studies reveals that on re-exfoliation of EG, thickness of Gr-layer decreases from 6-7 nm to 0.8-1.1 nm. This infers that re-exfoliation overcomes the problem of insufficient oxidation or inadequate pressure buildup during heat treatment.
Multiple Objective Preform Die Shape Optimization Design for Controlling Forging’s Shape and Deforming Force during Forging Process
Authors: Zhao Xin Hai , Zhao Guo Qun , Huang Xiao Hui , Luan Yi Guo
Published: August 2011

In order to decrease the cost of the material and energy during the forging process, multiple preform die shape optimization design was carried out in this paper. Based on the FEM, a sensitivity analysis method was used to perform the optimization procedure. The shape of the forging and deforming force of the final forging was used to express the cost of material and energy respectively. Using the weighted sum method, the total objective function was gotton. The coordinates of the control point of the B-spline used to represent the preform die shape was determined as the optimization design variable. The sensitivity equations of the total objective function with respect to the design variables was developed. The multiple objective perform design optimization software was developed by FORTRAN language. And then, the preform die shape of an H-shaped forging process is optimized. The total objective function, sub-objective function, the shape of the preform die and the final forging during the optimization were given. After the optimiztion, a near net shape forging was obtained. At the same time, the deforming force decreased. The optimization results are very satisfactory.
Influence of the Heating Conditions on the Asphalt Compositions by Grey System Theory
Authors: Yu M. , Wu Shao Peng
Published: August 2011

This paper carried out the applications of grey system theory to correlate asphalt compositions and heating conditions which consist of asphalt mass, heating temperature and length of heating time. To clarify the influences of the heating conditions, the asphalt compositions were determined, including four generic components, namely asphaltenes, resins, aromatics and saturates, the total contents of asphaltenes and resins replaced by A value, the total contents of aromatics and saturates replaced by B value, and the ratio of A and B(A/B value). Results show that all the four generic components are affected obviously by different conditions and none of the four generic is affected by the largest. The component most affected by asphalt mass is A/B value. In additionally, A value is influenced mainly by the length of heating time while B value by heating temperature.
Synthesis of Nanocrystalline (W, Ti)C from Respective Elemental Powders by Mechanical Alloying and Spark Plasma Sintering
Authors: Liang Jia Hong , Yang Chao , Li Xiao Qiang , Qu Sheng Guan , Li Yuan Yuan
Published: August 2011

The possibility of synthesizing nanocrystalline (W, Ti)C is investigated by spark plasma sintering of mechanically alloyed elemental mixed powders of W, Ti and C. The results show that wet-milling generates WxTi1-x instead of directly forming (W, Ti)C, and makes the graphite C transform into amorphous phase surrounding the formed WxTi1-x. Meanwhile, the grain size of the 70 h milled elemental mixed powders reaches about 50 nm under the wet-milling condition. Subsequently, nanocrystalline (W, Ti)C is successfully synthesized by spark plasma sintering of the 70 h milled elemental mixed powders. The formation of (W, Ti)C phase by SPS from the WxTi1-x and amorphous C generated by MA is simply explained based on our proposed model.
Measurement of Glucose Concentration in Cancer Cell by Catalyzed-Enzyme Reaction
Authors: Xia Fang Quan , Jin Wen Rui
Published: August 2011

In this work, glucose concentration in gastric cancer cell was determinaed based on a coupled enzyme catalyzed reaction. glucose oxidase (GOD) reacted with glucose to form gluconic acid and H2O2. In the presence of horseradish peroxidase (HRP), the H2O2 then reacted with 10-acetyl-3,7- dihydroxyphenoxazine (ADHP) in a 1:1 stoichiometry to generated the fluorescent products, resorufin. So that, the glucose concentration assay could be performed by fluorometric analysis resorufin. Glucose solution or Gastric cancer cells lysate were catalyzed and detected by epi-fluorescence microscopy in a quartz capillary fluorometer cell. The fluorescence intensity were analysis by the MetaMorph Software. The linear relationship of the glucose concentrations covered a range of 1.00×10-8-1.00×10-5 mol/L with a correlation coefficient of 0.9994. LOD was 5.30×10-9 mol/L(cL = ksB/b). The glucose concentration in cancer cells lysate was 8.03×10-6 mol/L (n =4).
Electron Stimulated Surface Chemical Reaction Mechanism for Phosphor Degradation
Authors: Swart Hendrik C. , Terblans Jacobus J. , Nagpure I.M. , Pitale S.S. , Ntwaeaborwa O.M.
Published: August 2011

Borates, phosphates, aluminates, silicates or sulphides are usually used as host lattices for display phosphors. These phosphors reacted similarly under electron bombardment. Nano and micron phosphors normally lose brightness upon bombardment with electron, ion or photon beams. A combination of techniques such as XPS (X-ray photoelectron spectroscopy), AES (Auger electron spectroscopy) and CL (cathodoluminescence) spectroscopy were used to show that the main reason for the degradation in luminescent intensity, of the different phosphors, under electron bombardment is the formation of a non-luminescent layer on the surface due to an electron stimulated surface chemical reaction (ESSCR). The decrease in luminance was found to be the result of the growing of a “dead layer” on the surface. In some cases, however, a thermodynamically stable layer formed on the surface as a result of the electron stimulated surface chemical reactions lead to CL stability of the phosphor. The formation of an altered layer (oxide layer) on the surface of the different phosphors leads to a decrease in the luminescent intensity at that specific wavelength and in some cases to an increase of the intensity at another wavelength.
Synthesis and Liquid Crystal Properties of a New Organometallic Palladium Complex
Authors: Liu Jian Qiang , Fu Xing Qi , Song Jian Ye , Fu Yun Xu , Zhang Xing Cheng , Hou Wan Guo
Published: August 2011

A new organometallic palladium coordinated liquid crystal that was written by PdS6 had been synthesized by chelating reaction of the tetrachloropalladate (PdCl42-) and the star-like liquid crystal (S6) containing four hexyloxyazobenzene mesogens in its periphery. The structure and liquid crystallinity (LC) of PdS6 were characterized by infrared absorption spectroscopy (IR), ultraviolet absorption spectra (UV), nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The phase behavior of PdS6 was Cr155N230I205N160Cr, its melting point and clearing temperature were higher than those of the free azo ligand S6, its mesophase range wass broader than S6’s. It will be used as a new type photoelectric functional material in the future.
Growth of p-Type AlN Crystals by C and Si Codoping
Authors: Wu Hong Lei , Zheng Rui Sheng , Zheng Wei , Yan Zheng
Published: August 2011

Based on our earlier theoretical investigation,p-type C:Si codoped AlN crystals were grown on SiC substrates by a sublimation method in a improved growth reactor. Hall-effect measurement shows that the AlN crystals have a high hole density of 1.4×1014cm-3and mobility of 52 cm2V-1s-1in spite of the high resistivity (896 Ω•cm). In the AlN samples, Si dopants act as donors due to substituting Al atoms, and most of C dopants act as acceptors for replacing N atoms. It is also observed that the activation energy of C acceptors in C:Si codoped AlN is reduced by codoping Si donors, which agrees with the computational results.
Grafting Biomimetic Phospholipid Zwitterionic Brushes onto Polycarbonateurethane for Improving Hemocompatibility
Authors: Zhao Hai Yang , Feng Ya Kai , Yang Da Zhi , Guo Jin Tang , Chen Qing Liang , Liu Jian Shi
Published: August 2011

In order to improve the hemocompatibility of polycarbonateurethane (PCU), the biomimetic phosphorylcholine (PC) group was introduced onto material surface. Brush structure having PC groups was formed by ultraviolet (UV) initiated polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve the hydrophilicity and hemocompatibility of PCU surfaces. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electrical microscopy (SEM) and water contact angle were used to characterize the chemical and physical properties of the modified PCU surfaces. Compared with original PCU, the PC-grafted PCU surfaces showed significantly high hydrophilicity as indicating by low water contact angle. The hemocompatibility of the PC-grafted PCU surfaces was evaluated by platelet adhesion test. The PCU surfaces modified with phosphorylcholine zwitterionic brushes showed effective resistance to platelet adhesion and high hemocompatibility. These PC-grafted PCU materials will have potential application as blood-contacting materials or devices due to their good mechanical and hemocompatible properties.
Effect of Shape Parameter on the Performance of 1-3 Piezoelectric Composites
Authors: Sun Min , Wang Hua , Huang Shi Feng , Cheng Xin
Published: August 2011

1-3 polymer-based piezoelectric composites were fabricated using epoxy as matrix by the cut-filling method. The influences of shape parameter on properties of the piezoelectric composite, which include the unit cross-sectional area and the aspect ratio w/t were analyzed. The results indicate that with the increasing of the unit cross-sectional area, the quality factor valueQmincreases and the hydrostatic piezoelectric voltageghincreases and then goes down rapidly while the PMN volume fractionφ(PMN) is kept under the 50%. When theφ(PMN) is 60%,ghis decreased. The trend of the hydrostatic figures of meritdh·ghis similar withghas the change of the unit cross-sectional area, but the value is different. In the 60% PMN volume fraction, the optimal value of thedh·ghis chosen. With the increasing of thew/t, the hydrostatic pressure sensitivityMh, thedh·ghvalues and theQmvalues are all decreased rapidly, and the thickness electromechanical coupling factorktis increased. In other words, the test results show that the smaller of unit cross-sectional area and thinner of thickness, the more helpful for frequency bandwidth and sensitivity when it is used in transducer.
Fabrication of Shortened Electrospun Fibers with Concentrated Polymer Brush Toward Biomaterial Applications
Authors: Huang Chih Feng , Yoshikawa Chiaki , Zhang Kun , Hattori Shinya , Honda Takako , Zawadzak Ewelina , Kobayashi Hisatoshi
Published: August 2011

In this research, we aimed to develop a new type of core-shell electrospun fiber, possessing “short” length (core) and “concentrated” polymer brush (shell). We prepared electrospun fibers with initiating moiety for surface-initiated atom transfer radical polymerization (SI-ATRP), one of living radical polymerizations. Then we grafted poly(sodium styrene sulfonate) (PSSNa) on the fibers by SI-ATRP. After the polymerization, we mechanically cut the electrospun fibers with a homogenizer, yielding regulated shortened fibers. Our ultimate goal is to make a novel shortened nanofibril biomaterial with concentrated brush as cell growth scaffolds. Therefore we expect that this unprecedented short nanofiber can be broadly applied as a biomaterial owing to the unique structures and properties of the concentrated brush. The details will be discussed.
The Effect of B on the Microstructure and Property of Ultra-Thick Abrasion Resistant Flux-Cored Wire Deposited Metal
Authors: Sun Jun Sheng , Zhang Ling Feng , Li Feng Bo
Published: August 2011

In this paper, a type of high efficient ultra-thick high-chromium cast iron surfacing flux-cored wire with a diameter of 6mm is designed. To solve the technological problem that the processing property of ultra-thick flux-cored wire can not satisfy the welding requirement, the author adopted “inter twist connection” and “inner wire” technologies. The effect of B on the microstructure and property of deposited metal was investigated by means of optical microscopy (OM), X-ray diffraction (XRD) and abrasion test. The test of engineering application was carried out on sinter raw material transport system in steel enterprises. It is proved that the welding efficiency and the service life of wear-resistant parts are significantly improved. The ultra-thick high-chromium iron surfacing flux-cored wire has a wide application prospect.
Plugging Performance Optimization Tests of Grouting Material for Sudden Water Inflow of Underground Engineering Construction
Authors: Li Li Ping , Li Shu Cai , Cui Jin Sheng , Li Zhao
Published: August 2011

Sudden water inflow is the typical geological hazard during the construction period of underground, especially for the karst area. According to a new type of polymer chemical grout material called Malisan, plugging performance optimization tests of different grouting material had been carried out, such as ordinary cement, superfine cement and special cement of HSC, the geo time, consolidating strength, anti-erosion property and comprehensive properties of grouting harnessing had been systematically analyzed and compared. Test results showed that the new type of polymer chemical grout material has the significant characteristics of controllable gel time, high consolidating strength, anti-scour performance, water swelling and extremely strong permeability, it is more effective than conventional grouting material for grouting harnessing of seepage, water spraying and water inflow with high water pressure, in addition, it is convenient for transportation, material configuration and process operation.
Effect of Emulsifier of Sizing Agent on Properties of Sizing Agent and Carbon Fibers
Authors: Chen Juan , Liu Jian Ye , Ge He Yi
Published: August 2011

In this paper, emulsion type sizing agents for carbon fiber were prepared by epoxy resin with the aid of various emulsifiers. Effects of emulsifier comprise and content on properties of emulsion were investigated by centrifugal sedimentation analysis and zeta potential measurement. Processing characteristics of desized and sized carbon fibers were compared. Results showed that the optimal emulsion was obtained when weight ratio of polyoxyethylene nonylphenol phosphoric ammonium (NP-10A) and polyoxyethylene styrenated phenol ether (602) was 2:1, ωe/r was 12%. The sizing agent emulsion could significantly improve the processability of carbon fibers due to the increase of abrasion resistance and flexibility of carbon fibers and the decrease of fluffs and breakage.
Effect of the Chemical Treated Kevlar Fiber on the Behaviors of Cement Mortars
Authors: Zhang Shui , Li Guo Zhong , Yuan Hai Yan
Published: August 2011

This work aims to evaluate the effect of Kevlar fibers with chemical treatment on the flexural strength, compressive strength and impact resistance of cement mortar. The experimental results exhibit that Kevlar fiber with a larger percentage can increase the flexural strength and improve the impact resistance of cement mortar, and the reinforcement effect of Kevlar fiber with chemical treatment is more obvious. The surface morphology of Kevlar fiber and the fracture surface of cement mortar reinforced with Kevlar fiber were observed by SEM, and the reinforcement mechanism of the Kevlar fiber on cement mortar was discussed.
An Exploration of 1-3 Cement/Epoxy Resin Based Piezoelectric Composite in Cement Hydration Reaction Process Monitoring
Authors: Xu Dong Yu , Qin Lei , Huang Shi Feng , Cheng Xin
Published: August 2011

1-3 type cement/epoxy resin based piezoelectric composite was designed and fabricated aiming at providing a new method for cement hydration monitoring. Combining with piezoelectric impedance technology, the cement hydration reaction process was monitored by using the composite. The research results show that in the initial cement hydration period, the resistance-frequency curves of the sensor drift toward low frequency direction, while the anti-resonance resistance value decreases gradually. With increasing cement hydration time, the resistance-frequency curves of the sensor drift toward high frequency direction and the anti-resonance resistance value shows fluctuation changes. The cement hydration reaction process can be divided into different periods according to changes of anti-resonance frequency and anti-resonance resistance value of the sensor.
Preparation and Properties of Cement Mortar Modified by VAE Latex
Authors: Chen Juan , Zhang Shui , Liu Jian Ye , Zhou Xin Rui
Published: August 2011

The effect of VAE latex modification on the physical properties of cement mortar is investigated. The porosity problem in cement mortar modified by vinyl acetate ester-ethylene (VAE) copolymer emulsion was successfully resolved by reasonable defoaming technique. It is shown that the bond strength and water resistance properties of modified cement mortar are better than unmodified cement mortar. When polymer-cement ratios ranged from 0 to 0.25, the bond strength and anti-permeability increased first and then decreased. The best value appeared at 0.1(polymer-cement ratio). SEM shows that the modified sample has compacted structure, polymeric films wrap the cement body and fill in the gap between cement and sand to improve the interfacial bond.
Study on Sintering Technology and Performance of Alite-Rich Cement Modified by C1.5Sr2.5A3S Mineral
Authors: Li Gui Qiang , Wang Shou De , Yin Chao Nan , Lu Ling Chao
Published: August 2011

The effects of the sintering temperature, sintering time and contents of calcium strontium suphoaluminate (C1.5Sr2.5A3) on the sintering technology of the alite-rich cement clinker modified by C1.5Sr2.5A3were researched by the orthogonal test method. X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and lithofacies analysis were used to investigate the compositions and structure of cement. The experimental results show that the optimal sintering temperature and sintering time of alite-rich cement clinker modified by C1.5Sr2.5A3are 1350 °C and 60 min, and the appropriate content of C1.5Sr2.5A3in the clinker is 2%. The introduction of C1.5Sr2.5A3in clinker can promote the formation of alite mineral at low temperature and decrease the sintering temperature of clinker by 100°C approximately. This new-type cement shows excellent mechanics properties. The compressive strength at 3d is up to 64.3MPa, which is increased by 26.7% comparing to that of alite-rich cement and the compressive strength at 28d is almost the same as that of alite-rich cement. For alite-rich cement clinker modified by C1.5Sr2.5A3calcinated at low temperature, alite still can be mass-formed, but the size decreases.
Performance of Different Projectile Nose Shapes in Normal Penetrating Armor Targets
Authors: Huang Guang Yan , Feng Shun Shan , Wu Guang , Li Shun Ping
Published: August 2011

Based on the cavity expansion theory, an analysis model of normal penetration of slender nose projectile into armor targets was established, and the variation relation curve of penetration depth and initial velocity when initial velocity is below ballistic limit was obtained. By carrying out ballistic impact test using 85mm smoothbore gun, various projectile nose shapes and armor target thickness and their effect on damage were considered. The research results have indicated that the damage of target is mainly ductile reaming and the shape of crater is almost the same as the projectile nose embedded in the target. Within a relatively low velocity range, nose shape has a greater influence on penetration depth. In contrast, within a relatively high velocity range, the target thickness has a greater influence on penetration depth. It can provide theoretical basis for the design of projectile noses and analysis of anti-penetration performance of armor targets.
Composite Soil: Fiber Inclusion and Strength
Authors: Chegenizadeh Amin , Nikraz Hamid
Published: August 2011

Reinforced soil has been among the most effective soil modification materials. Its use has been expanded rapidly into civil engineering, geotechnical engineering and pavement engineering. Reinforcing subgarde in pavement systems has always been an issue. This study focuses on effect of fiber inclusion on the strength of subgrade material. Plastic fiber was used for this investigation. Fiber contents and aspect ratio have been changed during these tests. The fiber percentage varied from 0 % (for unreinforced samples) to 2%. Clay was used as sub grade material. Unconfined compression tests were carried out to investigate behaviour of the composite under different condition. The fiber length and fiber content found to play important rule on the strength of composite. Furthermore it was observed that ductility of sample increased by fiber inclusion.
The Parameters Sensitivity Analysis of Battery Electric Vehicle Energy Consumption Economy
Authors: Chen Ming , Guo Li Xin
Published: August 2011

This paper establishes mathematical model of energy consumption economy for constant speed driving and acceleration driving. According to the model, influence degree calculation formulas of parameter sensitivity of vehicle mass, mechanical efficiency of transmission system, rolling resistance coefficient and air resistance factor to energy consumption economy are proposed, and analysis of energy consumption economy parameter sensitivity on a kind of BEV is conducted.
The Research of the Four-Bar Bionic Active Knee
Authors: Kim Ki Jun , Wu Cheng Dong , Wang Fei , Wen Shi Guang
Published: August 2011

The robot joints are usually rotational axis by two link joints, bionic features is not strong. The shortcomings of intelligent MR damper control multi-axis bionic knee can only provide resistance and certain sizes to regain momentum, cannot provide larger power, therefore this paper gives by the multi-axis four-bar structure, ball screw transmission multiaxial bionic active knee institutions. And analysis the human leg institutions and commonly used two-bar structure, through multi-variable optimization method to solve the design parameters of knee joint structure, the motor angular velocity and torque. And established in a bionic active the knee's virtual prototype.
Dimension Optimization Design of the Stewart Platform in FAST
Authors: Yao Rui , Zhu Wen Bai , Yang Qing Ge
Published: August 2011

China is now building the largest single dish radio telescope in the world in Guizhou province, which is called Five-hundred meter Aperture Spherical radio Telescope (FAST). A Stewart platform is introduced in FAST as an accuracy adjustable mechanism for feed receivers. The main purpose of this paper is to discuss dimension optimization design method of the Stewart platform based on three optimization objective functions. The optimization objective functions can reflect the operability and accuracy of the Stewart platform, and optimization design flow is presented according to the important degree of the three optimization objectives. Finally, a set of optimized parameters is obtained, and the study in this paper provides a basis for the coming optimization the feed support system for FAST in the next step.
A Novel Basic Conceptual Design and Analysis of a Morphing Wing Using Re-Entrant Hexagonal Cellular Structure
Authors: Dong Wen Jun , Sun Qin
Published: August 2011

A novel morphing wing structure is designed based on the concept of re–entrant hexagonal cellular structure. The re–entrant hexagonal cellular structure is adopted because of its ability to undergo large overall displacements with limited deformation in spanwise direction. The presented unconventional cellular based morphing wing structure can satisfy the requirements of configuration changing while wing morphing, which can makes the aircraft remain at the most effective state and perform multiple missions effectively and efficiently. Numerical analyses were performed to exploit the presented wing structures using commercial finite element method. It was shown that the morphing wing structure examined here had can change its relative thickness as much as 5%, which can make lift coefficient increase significantly. Therefore, the presented structure can be served as a smart variable wing structure and has much effective and efficient aerodynamic performance.
Effect of the Grain Size on Magnetic Properties of Nanocrystalline CoFe2O4 Ferrite
Authors: Liu Yin , Min Fan Fei , Qiu Tai , Zhu Jin Bo , Zhang Ming Xu
Published: August 2011

Nanocrystalline CoFe2O4 ferrite have been synthesized by a spraying-coprecipitation method. X-ray diffraction (XRD) and Transmission electron microscope (TEM) confirmed the formation of single-phase CoFe2O4 ferrite nanoparticles in the range 10 nm ~ 100 nm depending on the calcining temperature. The magnetic measurements show that specific saturation magnetization of nanocrystalline CoFe2O4 ferrite increases from 36.1 A•m2•kg-1 to 88.6 A•m2•kg-1 as grain size increases from 12 nm to 98 nm. The coercivity shows a peak with grain size, peaking at around 43 nm. The magnetic behaviour of nanocrystalline CoFe2O4 ferrite might be attributed to the effects of surface and random anisotropy.
Mechanical Property and Corrosion Resistant of Cerium-Bearing 2Cr13 Stainless Steel
Authors: Zhao Li Ping , Zhang Hui Min , Cui Chao Yu , Sun Xi Sen
Published: August 2011

The effect of the Ce on the mechanical property and corrosion resistant of the 2Cr13 stainless steel are studied in this research. The conclusions show that the hardness and tensile property of the 2Cr13 steel will decrease with the increasing of the amount of Ce. Although the corrosion resistance of 2Cr13Ce steel is better than 2Cr13 steel, the corrosion resistance of 2Cr13Ce contained 0.28%Ce is better than the steel contained 1.39%Ce. In this experiment, when the Ce content is 0.28%, 2Cr13 stainless steel can have good mechanical property and corrosion resistant.
Effect of Residual Stress in Ductile Iron Component on its Natural Frequency
Authors: Dong Xue Wu , Ren Dai , Wang Dong Qiang , Zhai Ya Fei
Published: August 2011

In the paper four components of ductile iron cast in different stress status, including the cast status, the status of vibratory stress relief and the status of thermal stress relief with 3 months of the natural stress relief and 10 years of the natural stress relief, are selected.X-ray diffraction method is used to measure residual stress and experimental modal analysis is for measuring natural frequency. A quantitative relation between residual stress in ductile iron cast component and its natural frequency variation is obtained. Thus we provide a reference for using natural frequency to evaluate the macroscopic residual stress of ductile iron material component. The results show that the peak value variation of macro residual stress in ductile iron component have a logarithmic relation to its natural frequency variation, and same as the mean value variation in macro-residual stress and its natural frequency variation.
Study on Properties and Preparation of Thermoplastic Polyurethane Hot-Melt Adhesive
Authors: Tian Jun Ling , Cao You Ming , Zhou Xin Qi
Published: August 2011

The thermoplastic polyurethane elastomer (TPU) was firstly synthesized by using polybutylene adipate (PBA) as soft segments, methane-4-4’-diisocyanate(MDI) and 1,4–butanediol(BDO) as hard segments. The polyurethane hot-melt adhesive was then prepared by adding the tackifying resin, filler and other auxiliaries into the TPU matrix. The structure of the synthetic products was characterized by Infrared Spectrum and the thermal properties and microstructure of polyurethane hot-melt adhesive was tested by the thermogravimetric(TG) and the scanning electron microscopy(SEM), respectively. The results showed that the thermoplastic polyurethane elastomer had the expected structure, the shear strength of polyurethane hot-melt adhesive increased with the pentaerythritol abietate content increasing when the addition of the pentaerythritol abietate is less than 20 wt%, and decreased with the content of CaCO3 filler and petroleum resin increasing, respectively; the thermal stability was improved, and the char yields of the polyurethane blends increased with adding the filler CaCO3. When the molar ratio of PBA:MDI:BDO was 1:2:1, the addition of pentaerythritol abietate and filler CaCO3 was 20 wt% and 30 wt%, the comprehensive performance of PU hot-melt adhesive was better and the shear strength was 7.37 MPa.