bluuebunny/crossref_metadata_2025 huggingface dataset:
The Preparation of a Kind of Interface Treatment Agent for Concrete
Authors: Zhao Su , Zhang Xiao , Liu Rong Rong , Fu Jin Ping , Liu Xiao Xuan , Liang Yu Chang , Hu Jia Jian
Published: August 2015

To prepare high strength, low cost concrete interface treatment agent, by chemical synthesis, obtained by varying the experimental conditions suitable temperature, stirring speed, emulsifiers and the like modifier content. When the initial reaction temperature is 70 °C, reaction steady temperature 80 °C, reaction to maintain the temperature 85 °C, stirring speed of 400 rpm / min, emulsifier ( polyvinyl alcohol and nonylphenol ether complex) content of 35% (by mass scores) , modifiers (methyl trimethoxysilane) content of 8% , the interface treatment agent synthesized better performance .
Numerical Test Research on High-Strength Concrete Square Columns with High-Strength Aseismic Transverse Reinforcement under Concentric Compression
Authors: Ding Hui , Wang Jian Ping , Song Li
Published: August 2015

This paper focuses on the the relationship between strength and ductility of high-strength concrete (HSC) columns with high-strength aseismic transverse reinforcement under concentric compression and its influencing factors. Some confining models for HSC with high-strength aseismic transverse reinforcement are introduced. Based on 10 groups of high-strength aseismic stirrup confined high-strength concrete square columns are tested under concentric compression, the influence of stirrup in binding strength and the ductility of concrete columns on different stirrup strength, different volume ratio of reinforcement, different stirrups type and different stirrup spacing form is studied by using finite element software ABAQUS. The results indicate that a good agreement is obtained between calculated results and experimental ones. The high-strength stirrup confined concrete columns can improve the bearing capacity and deformation performance of components effectively, laying the foundation of the applications of high-strength stirrups in concrete structures.
Interface Bonding Property Finite Element Simulation of Mo Fiber-Reinforced Polymer Concrete
Authors: Ren Xiu Hua , Zhang Jian Hua , Wang Wen Qiang , Yin Ji Cai
Published: August 2015

Interface bonding property of Mo-fiber reinforced polymer concrete not only depends on its material properties of components but also on microstructure characteristics of fibers including surface state, fiber content, fiber shape, bonding state between fiber and matrix, and so on. Interface bonding mechanism was firstly analyzed in the paper, and finite element simulation was employed to study the influence of fiber surface state, fiber number, bonding state between fiber and resin on interface property respectively. Research results show that the addition of Mo fibers can effectively restrain deformation of matrix, and scrap Mo fibers used as tool electrode material in Wire Electrical Discharge Machining before can improve interface bonding strength better than new smooth Mo fibers. With the increase of fiber number, deformation of the composite is decreasing. When fiber number is identical, maximum deformation of new and scrap Mo fiber-reinforced matrix in complete bonding state is respectively decreased by 12.6% and 14.5% on average compared with in complete debonding state.
Supramolecular Complex Formed by Fumaric Acid and Piperazine: Crystal Structure, and Synthon Cooperation
Authors: Wang Shi Ying , Xing Pei Qi , Geng Xiu Juan , Chen Rui Xin
Published: August 2015

A new molecular complex constructed by fumaric acid with piperazine has been prepared and characterized by single crystal X-ray diffraction. The number of fumaric acid involved in the complex equals to the number of N-protonated binding sites in the piperazine molecule. The structure contained infinite 1D supramolecular chains held together by robust, primary O–H•••O charge-assisted hydrogen bonds, and the 2D sheet like pattern constructed via the expected carboxyl-piperazine heterosynthon. Persistent N–H•••O interactions were found to play an important role in the formation of the final 3D arrays. The five dominant supramolecular synthons in the crystal structure are the heteromeric carboxylic acid•••piperazine hydrogen bond interactions, which prevail in the presence of widely differing chemical functionalities. Thermal stability of the compound has been investigated by thermogravimetric analysis (TGA) of mass loss.
Hydrothermal Synthesis and Structural Characterization of Orthorhombic LiMnO2 with Low Stacking Faults
Authors: Zhao Li Zhu , Chen G.
Published: August 2015

LiMnO2 are synthesized by hydrothermal technique by using Mn(CH3COO)2.4H2O and MnO2 with the same mole ratio which are dissolved in aqueous solution with different concentration LiOH. Structural characterization based on X-ray diffraction and Raman spectroscopy reveals that LiMnO2 is in a well-order orthorhombic structure with lower stacking faults compared to the LiMnO2 prepared by other techniques. Experimental results show that the concentration of lithium hydroxide in aqueous solution affect the quality of LiMnO2.
Effects of Al(OH)3 on the Structure and Properties of Foam Ceramics Cemented by Phosphate
Authors: Jia Cai Yun , Ding Rui , Liu Jun Cheng , Liu An Fa , Teng Dong Xiao
Published: August 2015

High alumina foam ceramics products with low density, high specific surface area, low thermal conductivity, corrosion resistance and other excellent physical and chemical properties are suitable for chemical, metallurgy and other related fields [1-4]. Alumina foam ceramics that compression strength increased by 200%, was prepared by Rizwan Ahmad through impregnation process using foamed rubber [5]. However foamed rubber was expensive and could be decomposed creating poisonous gases at high temperature. Zhou l z [6] prepared mullite porous ceramics with high strength by gel-casting method. Gel-casting is an effective method for preparation of ceramics products with large size and complicated shape. Fiber reinforced dense ceramics composite materials with excellent performance have been studied widely [7-10], it is also an important issue to adequately investigate the reinforcement of porous ceramics with fiber.
The Optimum of Preparation and Characterization of Aerogels like Hydrophobic Titania by Ambient Pressure Drying
Authors: Chen Jing , Zhang Bo , Wei Ming Quan , Men Jun , Miao Guang Wu
Published: August 2015

The influence of different factors in the alcogel preparation process and ambient pressure drying process on packing density of hydrophobic TiO2 aerogel synthesized by ambient pressure drying (APD) and the optimum preparation conditions were investigated by the orthogonal test with four-factor and three-level L9(34), respectively. The morphology and structural properties of hydrophobic TiO2 aerogels with different density were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetry (TG), N2 adsorption-desorption measurement and Scanning Electron Microscope (SEM). The results showed that the most important factors in the preparation process for TiO2 aerogels with low-density under ambient pressure are aging time, the volume ratio of C2H5OH to TBT, ethanol immersion time and hydrophobic modification time. The optimized preparation conditions are that aging time is 24 h, the volume ratio of C2H5OH to TBT is (7+7) : 5, the volume ratio of H2O to TBT is 1.7 : 5, the volume ratio of HAc to TBT is 1.7 : 5, ethanol immersion time is 24 h, hydrophobic modification time is 48 h, hexane solvent replacement time is 24 h and the drying temperature is 393 K. TiO2 aerogels with density of 460 kg/m3 was obtained at the optimized conditions. TiO2 aerogel with lower density displays higher specific surface area, porosity and pore volume as well as the larger pore size.
Fabrication and Characterization of Nano-Sized Starch Particles
Authors: Lin Hua , Li Qing , Feng Mu , Qin Li Zhao
Published: August 2015

An efficient method of preparing nanostarch using high-intensity ultrasonic irradiation and acid hydrolysis was discussed. The transmission electron microscope (TEM) showed that the nanosized starch particles were in shape of sphere with the size of 80-120 nm, and their surfaces were rough with many flocci. The Fourier transform infrared spectrometer (FT-IR) revealed that the products maintained the original biological characteristics, and the molecules did not undergo any chemical changes. In addition, the effects of experimental conditions were analyzed and a plausible mechanism was proposed to explain the formation of the nanostarch.
Cobalt Monoxide Nanoparticles Modified Glassy Carbon Electrodes as a Sensor for Determination of Nitrite
Authors: Huang Guang Jun , Zhang Jin Lei , Zhao Dan Dan
Published: August 2015

A new method for the determination of nitrite was established based on cobalt monoxide (CoO) nanoparticles modified glassy carbon electrode (CS-CoO/GCE). In 0.15mol/L pH 4.0 HAc-NaAc, the CS-CoO/GCE showed a remarkable catalytic and enhancement effect on oxidation of the nitrite. A linear dynamic range of 8.0×10-7 to 6.0×10-3 mol/L (R=0.997) with a detection limit of 1.0×10-7 mol/L was obtained. The electrochemical mechanism was been obtained. This method has been used to determine the content of nitrite in real samples.
Property Research of Silk Fibroin Nanofibers by Electrospinning Dissolved in CaCl2-Formid Acid
Authors: Zhou Yan , Wu Hui Ying
Published: August 2015

In this paper, property research of silk fibroin nanofibers by electrospinning dissolved in CaCl2-Formid Acid was discussed. The dissolve process, morphology, structure and mechanical properties of fibers were studied. It showed that more dissolution time was needed to dissolve silk with 1% CaCl2. The diameters of silk fibroin nanofibers decreased with the CaCl2 contents increased and the surface of 6%5% fibers was more uniform and smooth. After ethanol treatment, strong peak at 1628cm-1, 1517cm-1 and 1231cm-1 was corresponding to β-sheet. It was important to discover that silk fibroin was weakly destroyed in CaCl2-FA solvent system, and the regenerated silk fibroin nanofibers had better mechanical properties. The stress of 6%5% fibers was nearly 3 times to traditional way. With different content of CaCl2, the stress of 6%5% fibers was nearly 2 times to 6%1% fibers.
Silver Liquid-Like Film Prepared by Self-Assembly for Magnetic Fluid Deformable Mirrors
Authors: Min Ling Kun , Wu Zhi Zheng , Liu Mei
Published: August 2015

In this paper, a variety of methods to prepare nanometer thin films, such as LB film method, self-assembly method, vapor deposition method and oil-water two-phase interface deposition method, are first introduced and compared. Then the self-assembly method is used to prepare the silver liquid-like film for the magnetic fluid deformable mirror. The basic principle of configuration of the silver thin films is discussed and a large area of ordered and close-packed multilayer structures of encapsulated silver nanoparticles is fabricated. The results showed that the film has good reflectivity and stability.
Preparation and Adsorption Properties of Starch-g-Polyacrylamide/Montmorillonite Nanocomposites
Authors: Zhang Cai Ning , Wang Xu Man
Published: August 2015

By means of solution polymerization, a series of cross-linked starch-g-polyacrylamide/ montmorillonite (St-g-PAM/MMT) nanocomposites were prepared and used to adsorb methylene blue (MB). The effects of different preparation conditions on the adsorption capacity of the nanocomposites were investigated. The experimental results demonstrated that the prepared St-g-PAM/MMT nanocomposites were effective adsorbents for removal of MB from aqueous solution. Furthermore, adsorption capacity increased with the MMT contents up to 14% and decreased as the MMT contents further increased. Adsorption capacity increased with the increasing of the ratio of starch to acrylamide, whereas adsorption capacity decreased with the increasing of crosslinking agent contents.
Excimer Laser Crystallization of Nanocrystalline Silicon Thin Films
Authors: Deng Li Jie , He Wei , Li Zheng Ping
Published: August 2015

Nanocrystalline silicon (nc-Si) thin film on glass substrate is subjected to excimer laser crystallized by varying the laser energy density in the range of 50~600 mJ/cm2. The effect of excimer laser crystallization on the structure of silicon film is investigated using Raman spectroscopy, X-ray diffraction, atomic force microscopy and scanning electron microscopy. The results show that polycrystalline silicon thin films can be obtained by excimer laser crystallization of nc-Si films. A laser threshold energy density of 200 mJ/cm2 is estimated from the change of crystalline fraction and surface roughness of the treated films. The growth of grain is observed and the crystallization mechanism is discussed based on the super lateral growth model. The nanocrystalline silicon grains in the films act as seeds for lateral growth to large grains.
Research on Hall Effect of Graphene by Var Der Pauw Method
Authors: Hui Yu Xiang , An Nan , Chen Kai , Li Xiao Jun , Li Wei Long , Ren Zhao Yu
Published: August 2015

Graphene is a two-dimensional material consisting of single atomic layers of graphite. Its quality is markedly different from conventional graphite and semiconductor material. In this paper, electrical conductivity and Hall Effect of the graphene were measured at room temperature by Var der Pauw method. An ohmic contact of the sample and the electrodes was constructed and tested before the measurement of Hall Effect. With the help of the Var der Pauw method, the Hall voltages of the samples were measured under the static magnetic field and different input currents. Sequentially, a series of Hall parameters of graphene were obtained. The results shown that the Hall coefficient RH is 7.00*10-7 m3/C; the carrier concentration n is 10.52*1024 m-3 that is fifteen orders of magnitude bigger than silicon; the Hall element production sensitivity KH is 6.87*102 m2/C and the carrier mobility was 1,882.54 cm2·V-1·s-1 which is much bigger than silicon. The measurement results in this paper can provide some reference for graphene’s research and application in related areas.
Hydrothermal Synthesis and Luminescent Properties of Spherical LaPO4:Ln3+ (Ln3+= Eu3+, Dy3+, Ce3+, Tb3+)
Authors: Dai Jie , Li Guo Chao , Lv Meng , Zhou Rui Sen , Li Xia
Published: August 2015

Uniform LaPO4 and LaPO4:Ln3+ (Ln3+= Eu3+, Dy3+, Ce3+, Tb3+) microspheres have been selectively synthesized via a hydrothermal route, without using any catalyst, or template. X-ray diffraction, SEM, TEM, and photoluminescence spectroscopy were used to characterize the phase structure, morphology, and luminescence properties of the as-prepared samples. SEM results indicate that as-obtained samples have perfect spherical morphology with narrow size distribution. PL excitation and emission spectra demonstrated the LaPO4:Ln3+ phosphors show strong light emissions with different colors coming from different activator ions under ultraviolet excitation, which might find potential applications in fields such as light phosphor powders and advanced flat panel displays.
Compositional Dependence of Residual and Interfacial Stresses in Thin Film Systems with Substantial Thermal Mismatch Characteristics
Authors: Dobovšek Igor
Published: August 2015

We present an analysis of residual and interface stresses, caused by a change in external temperature field, due to mismatch in thermal and elastic characteristics in a dissimilar system of a thin film and a flexible substrate. A representative volume element of the system is defined as a heterogeneous two-phase layered element bonded at an interface in a sense of coherent bi-layer, where each phase possesses distinct elastic and thermal characteristics. We use a spatial averaging technique with particular form of strain field that satisfies compatibility equations in the bulk and at the interface. Derived special rule of mixtures yields rigorous estimates for residual stress distribution through thickness of the representative volume element. Corresponding distributions of stress fields are calculated for distinct magnitudes of compositional parameter representing the volumetric fraction of the film.
Effect of Pr on Wettability and Mechanical Property of Sn-0.3Ag-0.7Cu Lead-Free Solder
Authors: Feng Xiao Le , Yang Jie
Published: August 2015

The wettability of Sn-0.3Ag-0.7Cu-xPr solders on Cu substrate was determined by the wetting balance method， and the mechanical properties of Sn-0.3Ag-0.7Cu-xPr joints were investigated. The result showed that the wetting force of Sn-0.3Ag-0.7Cu-xPr is increased and the wetting time is decreased with the Pr content addition. Good wettability of Sn-Ag-Cu-Pr is obtained with around 0·05%-0·1% (mass fraction) Pr. When measured at 260°C， the wetting force of of SnAgCu solder was increased by 5.0% with 0.1%Pr and the wetting time of SnAgCu solder was descreased by 16.9%.The mechanical properties of soldered joints are enhanced with the addition of Pr， and the soldered joints possess the peak values of shear stress when the Pr addition is about 0.05% in Sn-Ag-Cu-Pr solder joint.
Investigation of Mid-Infrared Millimeter Wave Radome with Polycrystalline Magnesium Fluoride
Authors: Gu Hao , Yu Xing , He Li Hua , Feng Hong Quan
Published: August 2015

In this paper, the radome materials suitable for mid-infrared /millimeter wave multimode were introduced, as well as the properties. In comparison with the difference of the radome materials, the polycrystalline magnesium fluoride was promising for the radome of mid-infrared /millimeter wave multimode. Furthermore, the millimeter wave transparent properties of polycrystalline magnesium fluoride were studied by the simulation based on moment method and multilevel fast multipole method.
Preliminary Structure Characterization of UV Curing Paint Film
Authors: Qi Jing Jing , Shuai Mao Bing , Zhou Yuan Lin , Chang Feng Wen
Published: August 2015

PC film has some shortcomings such as low surface energy and strong rigidity. In order to improve the impact strength and adhesive properties of PC film, UV curing coating which was used on the surface of the PC film achieved good results. However, the combination between the UV curing paint-PC composite membrane had not been explained clearly. In this paper, we analyzed the structure of UV curing varnish oligomers. Fourier Transform Infrared Spectroscopy (FTIR) 、X-ray Photoelectron Spectroscopy (XPS) and Liquid Chromatograph Mass Spectrometer (LC-MS) were used to characterize. Through the experiment, we had achieved 4, 4’ -Isopropyliden-edicyclohexanol(HBPA) and Phthalic acid . The existence of the two substances explained the reason why the lacquer had good adhesion, and the result also laid the foundation for the the characterization of the molecular structure about the film later.
Orange Peels Derived Activated Carbon as Sulfur Cathode Supporter for Lithium/Sulfur Batteries
Authors: Yuan Guang Hui , Bai Jin Tao
Published: August 2015

Using Orange Peels as Raw Material, a Stacking Structured Carbon Material has been Synthesized through Carbonizing and Activating Process. an Orange Peel Carbon/sulfur (OPC/S) Composite as a Cathode for Rechargeable Lithium/sulfur (Li/S) Batteries is Designed by Loading Sulfur into the Orange Peel Carbon (OPC) via Simple Impregnation and Heat Treatments. the OPC/S Composite Exhibits a High Discharge Capacity of 1100 mAh g−1 at 0.1 C, which is 23% Higher than that of Pristine Sulfur. Moreover, OPC/S Shows much Better Rate Capability and Excellent Cyclability. this Enhanced Electrochemical Performance could Be Attributed to the Thin Sheets and Irregular Wrinkled Surface of the OPC, which Act as a Conductor to Provide a Highly Conductivity and Short Li+ Diffusion Distance, as well as Absorbs Polysulfides.
Research on Mechanical Properties of TiNi Shape Memory Alloy Wires Reinforced Al Matrix Composite Material
Authors: Yang Sheng Nan , Yang Su Yuan
Published: August 2015

TiNi/Al shape memory alloy (SMA) composite was fabricated by a vacuum hot-pressing method to investigate the phase , microstructure and mechanical properties. Phase analysis was conducted by XRD . Interface bonding between TiNi wire and Al matrix was observed by using SEM and EDS. Quasi-static and dynamic compressive mechanical properties of the composite were investigated by using electronic universal testing machine (INSTRON5985) and Split-Hopkinson Pressure Bar (SHPB),respectively. The experiment results show that new phases Ni4Ti3 and Ti2Ni precipitined from TiNi wire. Interfacial reactions occurred at the bonding between matrix and TiNi wire, creating a diffusion layer about 2μm thick. Both quasi-static and dynamic compressive mechanical properties are anisotropic , and the degree of the anisotropy increased with the increase of TiNi volume fraction.
Effects of Sr Doping Content on the Structure and Morphologies of La0.7SrxCa0.3-xMnO3
Authors: Wang Gang , Jiang Shao Qun , Zhang Qi , Wu Meng , Wang Ze Hua , Zhou Ze Hua
Published: August 2015

The La0.7SrxCa0.3-xMnO3 (x=0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3) were prepared by combining sol-gel method and high temperature sintering. The effects of Sr doping content on the structure and morphologies of the La0.7SrxCa0.3-xMnO3 finally sintered at 1050°C/1250°C were investigated based on the analyses of X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). The results show that the La0.7SrxCa0.3-xMnO3 exhibit single perovskite phase and the change of Sr doping content can result in phase structure transition. The La0.7SrxCa0.3-xMnO3 samples are rhombohedra structure in the range of 0.15≤x≤0.3. When x is no more than 0.1, the La0.7SrxCa0.3-xMnO3 samples sintered at 1050°C present distorted cubic structure. The microstructure of La0.7SrxCa0.3-xMnO3 sintered at 1050°C for 5h becomes more and more looser and its grains tend to refinement with the increase of Sr doping content when x is no less than 0.05. Increasing the final sintering temperature can improve the density and promote the grain growth of La0.7SrxCa0.3-xMnO3. In order to gain a dense microstructure, the final sintering temperature of La0.7SrxCa0.3-xMnO3 should be higher than 1050°C and should be suitably increased with the increase of Sr doping content.
Synthesis, Characterization and Applications of Late-Transition Metal Branched Polyethylene
Authors: Yu Wen , Zhang Dan Feng
Published: August 2015

The branched polyethylene (br-PE) was synthesized by [ArN=C(An)-C(An)=NAr]NiBr2 (An = acenaphthyl, Ar = 2,6-C6H3(iPr)2) in the presence of modified methylaluminoxane (MMAO) and methylaluminoxane (MAO). The effects of experimental conditions in which ethylene pressure, temperature and time were varied on ethylene polymerization were investigated. The structures of the obtained polyethylene were characterized by high-temperature NMR, high-temperature GPC and DSC. It was found that the activities from MMAO were higher than that from MAO about 10 times, which reaches 107(g/mol Ni·h). The branches of polyethylene prepared from MMAO were about 60/1000C, while that from MAO were about 80/1000C. The branched polyethylene with 84 branches / 1000C was used to toughen isotactic polypropylene (i-PP). The results show that the impact strength of blends improves as the content of branched PE increases. When the content of br-PE is 40%, the impact strength of the blend reaches to 50.24 KJ/m2, which is about twenty times that of PP (2.24 KJ/m2).
The Effect of Pre-Crosslinked CTBN on the Mechanical Properties and Morphology of Epoxy Resin
Authors: Song Xiao Xue , Xu Shiai
Published: August 2015

A novel kind of rubber toughened epoxy was prepared by in situ pre-crosslinking carboxyl-terminated butadiene-acrylonitrile copolymer (CTBN) in the epoxy matrix. The in situ pre-crosslinking of CTBN was initiated by BPO, followed by the curing reaction of epoxy to form the final pre-crosslinked CTBN/epoxy composites. Mechanical properties of epoxy are further improved by the incorporation of pre-crosslinked CTBN compared with its traditional CTBN/epoxy counterparts due to the improved interfacial strength between rubber and epoxy. SEM shows that the size of phase separated rubber particles of pre-crosslinked CTBN/epoxy decreases significantly.
Microstructure of In Situ Reaction TiB2/Zn-30Al-1Cu Composites Prepared by Spray Deposition Process
Authors: Liu Hong Wei , Wang Feng , Zhang Qiang , Li Xi Wu , Li Zhi Hui , Zhang Yong An , Xiong Bai Qing
Published: August 2015

An innovative spray deposition technique has been applied to produce in situ TiB2/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using optical microscopy, scanning electron microscopy, and X-ray diffraction. Both theoretical and experimental results have shown that the TiB2particulates are formed in the microstructure. It was found that the TiB2particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB2particles are about 2 μm in size. Moreover, the presence of the TiB2particles was led to increasing of α’ phase with less 2 μm size in the composites which have a tendency to decompose to α+η structure.
Study of Conductive and Friction Properties of Grease Containing Carbon Black Additive
Authors: Zhang Pei Lin , Wang Guo Gang , Zhao Yue Ju , Wu Hao , Xia Yan Qiu
Published: August 2015

The conductive and fiction properties of overbased calcium sulfonate complex grease and lithium grease containing carbon black (CB) additive were investigated in detail. The results indicate that CB can dramatically improve the conductivities of the greases. Also the tribol-test results indicate that the CB can dramatically improve the tribological properties of the greases. The lithium greases containing CB, have better tribological properties than overbased calcium sulfonate complex greases. Among the lithium greases, 5% CB contained grease performs the best friction reduction properties, and among the overbased calcium sulfonate complex greases, 6% CB contained grease performs the best friction reduction properties.
Ethanol Pretreatment on Etching of Nylon 6 Films Using Atmospheric Pressure Plasma
Authors: Xiong Qiu Yuan
Published: August 2015

The absorbed liquids in the substrate material may have a potential influence on atmospheric pressure plasma treatment. In order to investigate how the influence of ethanol pretreatment affects atmospheric pressure plasma treatment, nylon 6 films were treated by helium/oxygen plasma using atmospheric pressure plasma jet (APPJ). Water contact angle of the ethanol pretreated samples was close to that of the control. Scanning electron microscopy (SEM) showed that the ethanol pretreated sample surface had a little change on the surface. X-ray photoelectron spectroscopy (XPS) showed that the carbon component decreased and the oxygen component increased after plasma treatment. With the ethanol pretreatment, the T-peel strength values for the samples were similar to that of the control.
Microstructures and Mechanical Properties of Zirconium Dioxide Modified Carbon/Carbon Composites
Authors: Li Zhao Qian , Nan Bo Hua , Feng Guan Xiang , Hao Dong Dong
Published: August 2015

To improve the preparation technology and mechanical properties of carbon/carbon composites, a kind of Zirconium dioxide modified Carbon/carbon (C/C–ZrO2) composites were prepared by Sol-Gel Process combined with isothermal chemical vapor infiltration (ICVI) method. This method could shorten preparation cycle greatly to reduce the cost. The microstructures and mechanical properties of the C/C–ZrO2 composites were investigated. The results indicate that the ZrO2 modified phase is uniformly distributed in the carbon matrix, the bending strength and modulus of C/C–ZrO2 composites are much higher than unmodified C/C composites due to its particle toughening and fiber toughening.
Effect of Radiation Dose on the Creep Properties
Authors: Reznicek Martin , Skrobak Adam , Stanek Michal , Kratky Petr , Manas David
Published: August 2015

New trends in development and research of construction polymeric materials allow modification of their properties. This change of properties may represent a significant financial burden, which will be reflected in the product price. This article will consider the degree of impact of such modification on finished products. Improving creep characteristics are not directly proportional to the amount of the dose. Moreover is solved the dose amount compared to the value added, which will translate into better mechanical properties. The results of these measurements show that the most appropriate dose of radiation in terms of the mechanical properties of the dose is 198 kGy. However, in terms of value added seems best a much smaller dose.
General Method for Optimizing Composite Patch Repairs
Authors: Ait Yala Abdelmadjid , Akkouche Abderrahmanne
Published: August 2015

The aim of this work is to define a general method for the optimization of composite patch repairing. Fracture mechanics theory shows that the stress intensity factor tends towards an asymptotic limit K∞.This limit is given by Rose’s formula and is a function of the thicknesses and mechanical properties of the cracked plate, the composite patch and the adhesive. The proposed approach consists in considering this limit as an objective function that needs to be minimized. In deed lowering this asymptote will reduce the values of the stress intensity factor hence optimize the repair. However to be effective this robust design must satisfy the stiffness ratio criteria. The resolution of this double objective optimization problem with Matlab program allowed us determine the appropriate geometric and mechanical properties that allow the optimum design; that is the selection of the adhesive, the patch and their respective thicknesses.
Effect of Cooling Rate, Tungsten Fiber Addition and Annealing on Deformation and Mechanical Properties of Zr-Based Bulk Metallic Glasses Under a Nanoindenter
Authors: Si Yi
Published: August 2015

The deformation and mechanical properties of Zr-based bulk metallic glasses (BMGs) under a nanoindenter and the effect of cooling rate, the effect of cooling rate, tungsten fiber addition and annealing on them have been studied by means of a nanoindentation instrument and a scanning electron microscope (SEM). The results indicate that the deformation of Zr-based BMGs under a nanoindenter is characterized by multiple shear bands and viscous flow which confirms the existence of a amount of plastic deformation. For pure quenched Zr-based BMGs, the larger the size of samples or the nearer the location away from the surface of a same sample, the smaller the values of microhardness (Hv) and elastic modulus (E); Annealing and tungsten fiber addition enhance the values of Hv and E; meanwhile, they also significantly change morphology around a nanoindenter and the amount of plastic deformation. The mechanism of plastic deformation is preliminarily analyzed.
Research of Rust Layer Stabilization on Bare Steel
Authors: Huang Xian Qiu , Cheng Peng , Lang Feng Jun , Pang Tao , Ma Ying , Liu Jian Rong
Published: August 2015

The performance of bare steel’s rust stabilization was studied using cycle immersion corrosion test and X-ray diffraction. The results showed that after specimens were corroded in 3% NaCl solution, rust bubble of stabilized specimen was smaller than rust bubble of unstabilized specimen, corrosion rate of stabilized specimen was lower than corrosion rate of unstabilized specimen, and rust layers of stabilized specimen and unstabilized specimen were mainly composed of γ-FeOOH and Fe3O4.
Study on Microstructure of the Matrix/Dense Inner Layer Interface in Micro-Arc Oxidizing on Magnesium Alloys
Authors: Chen Xian Ming , Pan Qing Lin
Published: August 2015

An extensive study was made of the boundary area microstructure between the matrix and dense inner sublayers of the ceramic coating formed on AZ91 magnesium alloy substrate by micro-arc oxidation(MAO).The coating was prepared in an alkaline electrolytic solution composed of 5-20g/l of NaH2PO4, 1-5g/l of NaOH, 5-8g/l of KF; 0.5-2g/l of Na3C6H5O7, and 0.5-2g/l of EDTA , employing a constant-current controlled AC power supply with a current density of 10-30A/dm2; and the microstructure of the coatings was characterized using transmission electron microscopy(TEM) and scanning electron microscopy(SEM). It was found that (1) the main constituent of the coating adjacent to the boundary was microcrystalline and nanocrystalline; (2) the microhardness of the coating adjacent to the boundary was improved than that of the matrix. It was due to the formation of the intermixing of Mg and MgO and their grains were refined, these leaded to fine-crystal strengthen.
Influence of Oxidation Temperature on the High-Temperature Oxide Film Forming Behavior of T22 Heat-Exchange Tubes
Authors: Gu Bao Shan , Lu Qiang , Fu Ji Yi , Yuan Xiao Bao , Wang Yan , Yang Pei Yan
Published: August 2015

In this study, without changing the whole manufacturing process of T22 coiled tubes, high-temperature oxide films are formed through atmosphere adjustment by taking advantages of the cooling process after stress elimination heat treatment. The corrosion resistance of T22 heat-exchange tubes is improved, which are used in the steam generators (SG) of high-temperature gas cooled reactors (HTR). The surface microscopic morphology of the oxide films is observed using a scanning electron microscope, and the structure of these films is characterized using an X-ray diffractometer. The stability of the high-temperature oxide film forming process is investigated using TG-DTG, as well as the thermal expansion coefficient of the films. The results prove that: (1) The oxide film generated at 550 °C is uniform and dense; (2) The oxide films formed at various holding temperatures are mainly consisted by Fe2O3 and Fe3O4. When the holding temperature is 550 °C, the content of Fe3O4 is the highest as 70.1%; (3) The films are stable when placed in inert atmosphere (N2) below 900 °C, and there is not any change in the composition and structure of the films even after reacting with steam at 550 °C for 24 h; (4) The expansion coefficient of high-temperature oxide films is very close to that of the matrix of the heat exchange tube, and the difference between these two thermal expansion coefficients is 5.3×10-9 mm/°C.
Effect of Ce Substitution on Mechanical and Thermal Properties of Tetragonal YSZ: First-Principles Calculations
Authors: Jin Lei , Li Pei Zhong , Zhou Guo Dong , Gao Wei , Ma Jiang Ning , Zhang Wei , Wang Chun
Published: August 2015

The effect of impurity Ce on the mechanical and thermal properties of tetragonal ZrO2 stabilized by rare earth element Y (YSZ) have been studied using first principles density functional theory within generalized gradient approximation (GGA) for the exchange correlation potential. The predicted elastic constants indicate that YSZ and Ce doped YSZ (CeYSZ) are mechanically stable structures. And then the numerical estimates of bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, sound velocity and minimum thermal conductivity were performed using the calculated elastic constants and analyzed for the first time. The values of sound velocity from different orientations are also reported. The agreement between the results of the available experiments and our calculations was satisfactory. Our calculated results indicate that Young’s modulus, hardness, mean sound velocity and minimum thermal conductivity of YSZ can be decreased by Ce substitution. The reasons are from the “softened” Ce-O bond strength using bond population and relative volume change under external hydrostatic pressure. Chemical bonding nature was also analyzed from the density of states and electron density difference.
Numerical Analysis of the Influence of Graphite Nodule Size on the Pitting Resistance of Austepered Ductile Iron Gears
Authors: Accorsi Gans Luiz Henrique , Guesser Wilson Luiz , Luersen Marco Antonio , da Silva Carlos Henrique
Published: August 2015

In this work, an experimental study of wear evaluation in combination with a finite element analysis (FEA) was carried out for austempered ductile iron (ADI) used in gears. Two different ADI materials were used to produce gears which were tested in a FZG back-to-back test rig. The experimental results were compared to those of carburized AISI 8620 steel and induction hardened AISI 4140 steel gears. The wear resistance for pitting and spalling on the gears surfaces were measured using image analysis. Comparing the two types of ADI, the one with smaller nodules showed a higher pitting resistance. In contact fatigue tests with severe load, the carburized AISI 8620 steel proved to be superior to ADI. However, ADI with smaller nodule size presented wear resistance similar to that of induction hardened AISI 4140 steel. The FEA was conducted using the commercial code ANSYS 11.0 and aimed to provide a better understanding of the microstructural effect on the stress state of subsurface regions. From the numerical results in ADIs, it was concluded that the nodule size affects the gears life independently of the mechanical properties of the matrix. The size and number of nodules affects both the nucleation and the propagation stages of cracks. ADIs with higher amount of nodules have a superior wear resistance by pitting. Also, compared to the Hertz contact theory (valid for isotropic materials), the presence of graphite nodules induced the maximum shear stress point moves toward the surface.
Investigating the Effect of Hydrophilic Surface Modification on Droplet Evaporation
Authors: Wu Shen Chun , Lin Sin Jie , Wang Dawn , Chen Yau Ming
Published: August 2015

In this study, surface modification of stainless steel flat plates was performed using nanoscale bilayers assembly method to increase the surface’s hydrophilicity and enhance evaporation. Thin layers of SiO2 nanoparticles layered onto the stainless steel surfaces were used to modify their surface properties, and the relationship between the number of layers (0~20) and water’s hydrophilicity (surface tension) was investigated. The effects of modification on evaporation were then tested using de-ionized water. According to experimental results, surface modification was able to reduce the contact angle of water on stainless steel flat plate from the unmodified 87o to 7o at 18 layers, significantly increasing the hydrophilicity of the surface. Evaporation experiments show that the evaporation heat transfer enhancement for droplets on stainless steel plates is at least 300%.Keywords: bilayers assembly, hydrophilicity, surface modification, evaporation performance
Experimental Study on Laser Melting of Cemented Carbide Coatings by High Velocity Oxy-Fuel Spraying
Authors: Fan Xiang Fang , Wu Wei , Ye Jiang , Gong Ren Zheng
Published: August 2015

Ni60AA and DZ-WC-12Co cemented carbide layer was prepared on 45 steel by high-speed flame spraying, then remelted by 5KW continuous wave CO2 laser. The micro-structure was analyzed by Olympus GX51 .micro hardness and the micro hardness was measured by HXY-1000TAY micro hardness meter. The wear resistant of coating was tested by MM-W1B vertical universal testing machine. The results showed that laser melting significantly eliminate the carbide layer unmelted carbide particles, holes and cracks and other defects, the micro-structure is finer and more uniform. After laser re-melted, the average micro hardness of hard alloy layer is up to 647HV, which is five times of the matrix. Under the experimental conditions, the friction coefficient of hard alloy layer drops from 0.1373 to 0.0948 by 31%.The wear-resistance of cemented carbide layer is improved by laser melting.
Conjugation, Identification and Bionomics Analysis of EGFR Targeting Drug TGF α-Saporin as a Bioactive Stent Coating Material
Authors: Yang Jun , Li Fang , Zeng Ou , Luo Jian , Wu Zhi Xiong , Xiao Ting , Chu Chun
Published: August 2015

Objective: To identify and testify the cytotoxicity of the EGFR targeting drug TGFa-SAP conjugated and synthesized with N-succinimidyl-3 (2-pyridyldithio) propionate on human hepatoma cell line BEL-7404 cells and proliferating vascular smooth muscle cells. Methods: Conjugation of saporin with TGFa was accomplished after derivatization of TGFa and saporin with N-succinimidyl-3 (2-pyridyldithio) proprionate and the purification of the conjugate was achieved through Eppendorf Centrifugal Filter. Cytotoxicity assays were measured by MTS assays. The value of Thymidine incorporation in BEL-7404 cells was measured by 3H-thymidine uptake. Results: Cytotoxicity assays testified that TGFa-SAP conjugate could remarkably inhibit the proliferation of human hepatoma cell line BEL-7404 cells in vitro. The value of thymidine incorporation of BEL-7404 cells in TGFa-SAP groups significantly decreased compared with the control group (P<0.05), and it had dose-dependence on TGFa-SAP’s concentration. But Saporin could not affect BEL-7404 cells even at higher level (10-5). TGFa-SAP conjugate had effective cytotoxicity on proliferating vascular smooth muscle cells, also. Conclusion: The results indicated that the conjugated EGFR targeting drug TGFa-SAP had effective cytotoxicity not only on BEL-7404 cells, but also on proliferating vascular smooth muscle cells, as a potential bioactive stent coating material.
Molecular Mechanism on Inhibition of MB Angiogenesis by Curcumin Blocking the Wnt/β-Catenin and NF-κB Signaling Pathway and Inhibiting the Expression of VEGFs/VEGFRs
Authors: Gao Minna , Zeng Bo , Zhang Xiong , Yu Li
Published: August 2015

Medulloblastoma (MB) is one of the most common malignant tumors in pediatric brain. The genesis and development of MB are related to abnormal and persistent activation of the Wnt/β-catenin abnormal and NF-κB signaling pathway. The VEGF, as the main target gene regulated by the crosstalk between the two signaling pathways, is closely related to MB. In previous studies, We found that the genesis of MB is associated with the abnormal expression of key molecular GSK-3β,β-catenin and downstream target gene PPAR-gamma in Wnt /β-catenin signaling pathway.It also found that, there have abnormal expression of VEGF-A, C and its receptor VEGFR-2 in MB, and positively correlate with β-catenin. curcumin has anti-angiogenic function, but the exact mechanism is unclear. Combining with the early research findings and the latest literatures, we hypothesized that curcumin can inhibit the expression of VEGFs/VEGFRs by blocking the Wnt/β-catenin and NF-κB signaling pathway.
Influence of Hydrodynamic Cavitation on the Viscosity of Raw Sugar Solution
Authors: Wang Peng Fei , Huang Yong Chun , Wu Xiu Chao , Ren Xian E , Yang Feng
Published: August 2015

Viscosity of raw sugar solution is an important factor affect the smelting process. This paper researched the changes and rules of raw sugar solution intrinsic viscosity under the treatment of turbine cavitation. Different operating parameters such as the raw sugar solution (0.10 g/mL, 0.15 g/mL, 0.20 g/mL, 0.25 g/mL, 0.35 g/mL, 0.45 g/mL), outlet pressures (0.1 MPa, 0.2 MPa, 0.3 MPa, and 0.4 MPa), solution temperature (30 °C, 40 °C, 50 °C, 60 °C and 70 °C), and treatment time (1 min, 2 min, 5 min, 10 min, and 20 min) were investigated. The experimental results show that: with the increase of the concentrations, intrinsic viscosity decrease rate reduced gradually; with the increase of the outlet pressure, intrinsic viscosity decrease rate increased gradually; with the increase of solution temperature, intrinsic viscosity decrease rate increased gradually; with the increase of cavitation time, intrinsic viscosity decrease rate increased gradually, but the increased rate is decreased, and at the beginning of the cavitation, the intrinsic viscosity decrease rate decreased faster.
Effect of Sc, Y, Yb, Hf, Ce on Mechanical and Thermal Properties of La2Zr2O7: First-Principles Calculations
Authors: Jin Lei , Li Pei Zhong , Jiang Chun Zhu , Zhou Guo Dong , Zhou Hai Bin , Wang Chun
Published: August 2015

In order to achieve better understanding of the effect of dopant (Sc, Y, Yb, Hf and Ce) on elastic stiffness and thermal properties of La2Zr2O7. The related calculations were performed using the first principles methods. The predicted elastic constants indicate that La2Zr2O7 and oxidations-La2Zr2O7 (oxidations refer to Sc2O3, Y2O3, Yb2O3, HfO2 and CeO2) are mechanically stable structures. And then the numerical estimates of bulk modulus, shear modulus, Young’s modulus were performed using the calculated elastic constants. After these mechanical properties are obtained, sound velocity, Debye temperature and theoretical minimum thermal conductivity of La2Zr2O7 and oxidations-La2Zr2O7 are calculated and analyzed in detail. The available experimental results and our calculations are basically satisfactory. The calculated results indicate that Young’s modulus, mean sound velocity, Debye temperature and minimum thermal conductivity of La2Zr2O7 can be decreased by dopants. CeO2 has extraordinary ability to decrease thermal conductivity in these dopant oxidations.
Effects of Plant Compound Curcumin on Learning and Memory of Chronic Cerebral Hypoperfusion Rats
Authors: Tang Li , Li Yu
Published: August 2015

Vascular dementia (VD) is the cognitive impairment clinical syndrome caused by various cerebrovascular diseases. At present the exact causes of VD are not clear, it is believed that ischemic cerebral vascular disease is one of the factors. Hypertension, hyperlipidemia, diabetes, tobacco and alcohol addiction are risk factors of VD. Most of them can be traced back to the youth. Curcumin has a neuroprotective effect in Alzheimer’s disease (AD) and other neurodegenerative diseases. But the effect of curcumin on brain injury caused by chronic cerebral hypoperfusion was unclear. In this study, chronic cerebral ischemia model was used to investigate the effect of curcumin on learning and memory ability of young and aged rats and to explore the mechanism of neuroprotective effect of Curcumin. The result showed that Curcumin can reduce the brain damage both in young and aged VD rats and improve learning and memory ability, and the effect was dose-dependent, without age difference. The pathological injury of the hippocampus might be one of the mechanisms of curcumin improving cognitive impairment of VD rats.
Study of Endocrine Disruptors in the Sediment of a South Brazilian River
Authors: Nascimento Irajá Do , Vieceli Nathália Christine , Schmitz Michele , Glaeser Fernanda
Published: August 2015

This study investigated the occurrence of di (2-ethylhexyl) phthalate (DEHP) di-n-butylphthalate (DBP) and bisphenol A (BPA) in river sediment. The samples were collected from three selected points and extracted by sonication, using n-hexane and ethanol. The organic extracts were analyzed by gas chromatography with flame ionization detection (GC/FID). DBP and BPA were not detected. The average concentrations of DEHP range from 0.72 (±0.04) to 27.90 (± 3.05) ng g-1 of sediment. The best solvent for the extractions was n-hexane. However ethanol also shows good extraction yields of DEHP. These results showed an important anthropic contribution for the river contamination by endocrine disruptors.
Adsorption and Dehydration of Water Molecules from α, β and γ Cyclodextrins — A Study by TGA Analysis and Gravimetry
Authors: Christy Alfred A.
Published: August 2015

The adsorption and desorption of water molecules from α, β and γ-cyclodextrins were studied by gravimetric and thermogravimetric analysis. Cyclodextrins like all the other carbohydrates have tendency to adsorb water molecules. However, their cyclic nature tends to affect the adsorption patterns. The cyclic nature of the cyclodextrins facilitates the formation of hydrogen bondings between OH groups of the neighbouring glucose units. The C2(1)-OH forms hydrogen bonding with C3(2)-OH. The extent of the hydrogen bond formation and strength of the hydrogen bond affect the way the adsorption and dehydration of water molecules from cyclodextrins take place.