bluuebunny/crossref_metadata_2025 huggingface dataset:
Application and Mechanism of a New Type of Polyethylene Modifying Additive in Asphalt Mixture
Authors: Sui Yuan Yuan , Chen Zhong Da
Published: December 2011

Asphalt mixture is often modified by adding modifier in order to improve the pavement performance such as high temperature stability, low temperature crack resistance and water stability. The author applies a new type of polyethylene modifying additive for asphalt mixture. The adding method of modifier is different from traditional method. Three modifiers were used in this study. It has been found that each modifier can improve the asphalt mixture performances. The author analyses the reason why modifying additive can improve asphalt mixture performances and give an advice to choose the type of modifying additive.
Research on Temperaure Variation of Bridgewire with Infrared Thermal Imaging
Authors: Zhang Wen Chao , Peng Hong Zheng , Su Chun Long
Published: December 2011

Bridgewire of a thin resistive wire widely used in electric explosive devices (EED) as a transducer of electronic energy to thermal energy provide the ignition of energetic compounds. In this paper the temperature variation laws of bridgewire as core component and most sensitive part for EED under the constant current were investigated though infrared measuring temperature system. The result indicates that the thermodynamic equilibrium from the bridgewire was realized in two senconds and the maximum temperature for bridgewire caused by the current rises as quadratic parabola with increasing of current acting on bridgewire. Meanwhile the safety current for bridgewire with large diameter is higher than that for bridgewire with small diameter. The maximum temperature variation curve for bridgewire of different diameters with current received from the infrared thermal imaging can provide the quantitative evidence supporting the predication of safety current for bridgewire and guidelines for engnieers to realize the activation of EED as expected safely.
Using Taguchi Method to Improve 3D Polishing Process Capability for Optical Fiber
Authors: Hung Tsung Hsin , Lin Wen Tsann , Wang Shen Tsu , Li Meng Hua , Chang Shih Chieh
Published: December 2011

This study used Six Sigma DMAIC five-phase improvement procedures for an empirical research on a multinational optical interconnect manufacturer. The Taguchi method was used for the design of experiment, and the data obtained from the orthogonal table were used to determine the key factors and levels, in order to propose the optimal combination of processing parameters and levels for fiber patch cord 3D polishing. The combination of rough polishing time of 30s, polishing pressure of 0.02pa, polishing pad hardness of 65 degrees, and the fine polishing time of 80s could produce the fittest parameters for a satisfactory level, reduce the defect rate and waste of production cost, and reach the Six Sigma standard. The results proved that the improved process capability model, as constructed by this study, can effectively improve the apex offset quality of fiber patch cords. The findings can serve as references for engineers to improve the quality and production process capability.
Stability of Generalized Quadratic Functional Equation in Non-Archimedean Fuzzy Normed Spaces
Authors: Ravi K. , Narasimman P.
Published: December 2011

In this paper, we obtain the general solution and investigate the Hyers-Ulam-Rassias stability of the Generalized Quadratic functional equation in non-Archimedean fuzzy normed spaces.
Fabrication and Reaction Mechanism of In Situ TiC and TiB2 Reinforced Mg Matrix Composites
Authors: Shamekh Mohammed , Pugh Martin , Medraj Mamoun
Published: December 2011

TiC and TiB2compounds in the form of interpenetrating network reinforced AZ91D magnesium matrix composites have been successfully synthesized by anin-situreactive infiltration technique. In this process, the ceramic reinforcement phases, TiC and TiB2, were synthesizedin-situfrom elemental powders of Ti and B4C without any addition of a third metal powder such as Al. The molten Mg alloy infiltrates the preform of Tipand B4Cpby the capillary force. The microstructure and reaction mechanism are investigated using SEM/EDS and XRD analysis. The results show that the processing parameters such as temperature, holding time and the green compact relative density have a significant influence on the reaction mechanism and the fabrication of the composite. In addition, the infiltrated Mg acts as an intermediary that makes the reaction possible at a lower temperature than that required for solid-state reaction between Ti and B4C. Microstructural characterization reveals a relatively uniform distribution of the reinforcing phases, TiC and TiB2in the Mg matrix.
Microstructure Evolution in a P911 Steel under Creep Conditions
Authors: Kipelova Alla , Belyakov Andrey , Kaibyshev Rustam
Published: December 2011

Microstructure evolution in a P911 heat resistant steel was examined under conditions of aging and creep at a temperature of 600°C and an applied stress of 200 MPa. The tempered martensite lath structure (TMLS) evolved after heat treatment consisted of prior austenite grains (PAG), packets, blocks and laths. The mean transverse lath size and the interior dislocation density were about 345 nm and 3.5 × 1014 m-2, respectively. Various second phase particles precipitated upon tempering. Fine MX carbonitrides were homogeneously distributed throughout the tempered martensite laths, while relatively coarse M23C6 carbide particles were located on high-and low-angle boundaries. Upon creep test, precipitation of Laves phases was found. The stability of TMLS during creep is discussed in detail.
Recovery Behaviour at the Inter-Alloy Region of a Cold Rolled Clad Aluminum Alloy
Authors: Bag Debartha , Diak Bradley J. , Jin Hai Ou
Published: December 2011

This study examines the recovery behaviour of the inter-alloy region between a core AA6XXX clad with AA3003 after 72% rolling reduction. Sample coupons were heated isochronally or isothermally, at different temperatures or times, respectively, to probe the recovery kinetics of x-ray peak broadening, x-ray macro-texture, and micro-hardness from the cold rolled state. The inter-alloy region had a strong β-fibre typical of rolled Al. The recovery of the {220} and {311} x-ray line profiles were observed between anneals. The full width half maximum was determined from a pseudo-Voigt fit of the profiles to obtain the defect-related information. Distinct changes in the peak shape and microhardness were observed above 80°C (start of recovery), which goes on all the way to 300°C due to recovery, and beyond 300°C both hardness and peak width drop rapidly (recrystallization start), the latter behaviour being closer to AA3004. Modified Williamson-Hall analysis confirms that recovery is due to dislocation annihilation.
Effect of Die Temperature on Tensile Property of Rheocast Phosphor Bronze
Authors: Kose Takahisa , Uetani Yasuhiro , Nakajima Katsuyuki , Matsuda Kenji , Ikeno Susumu
Published: December 2011

Semi-solid slurry of phosphor bronze with fine solid granules for rheocasting was tried to make by passing the low-superheat melt through an opening between a rotating regular octagonal rotor and a circumscribed chill block. The effect of rotational speed on the structure of a solidified small ingot was mainly investigated. The ingot structures were changed from the dendrite of rotor-free condition to the rosette at the rotational speed of 50rpm, and the granular with a mean size of about 50μm at higher than150rpm. The slurries made at 150rpm were rheocast to a cylindrical shape cavity within a die kept at different temperatures from 573 to 1173K by the use of a high pressure casting machine. Microstructures of rheocast cylindrical shape products were granular at the die temperatures lower than 773K and changed to grained one as like recrystallized at higher than 973K. Together with the microstructure change, poor tensile ductility less than 3% at the lowest die temperature was improved up to about 60% at 973K.
Ductilization of a Ni3(Si,Ti) Intermetallic Alloy by Addition of Interstitial Type Elements
Authors: Kosaka Hisashi , Kaneno Yasuyuki , Takasugi Takayuki
Published: December 2011

The effect of a concomitant doping of interstitial type elements boron (B) and carbon (C), and boron (B) and nitrogen (N) on tensile properties of a Ni3(Si,Ti) intermetallic alloy was investigated in the temperature range between room temperature and 973 K. It was found that the concomitant doping of (C/B) and (N/B) remarkably improved the intermediate-temperature tensile elongation of the Ni3(Si,Ti) alloy compared with the simple doping of B or C. It was also shown that the fracture surface of the alloy doped with (C/B) and (N/B) exhibited the ductile transgranular fracture mode while that of the alloy doped with only B showed a brittle intergranular fracture mode at 773 K. These results clearly indicate that the concomitant doping of the interstitial type elements are useful for improving the intermediate-temperature tensile ductility of the Ni3(Si,Ti) alloy.
Microstructure Observation of AM60 Magnesium Alloy Solidified by Rapidly Quench
Authors: Maekawa Tatsuya , Furui Mitsuaki , Ikeno Susumu , Yamaguchi Tomoyasu , Saikawa Seiji
Published: December 2011

In solidification theory, with a slow cooling rate such as sand mold casting, it is easy to segregate the solute aluminum near the grain boundary of primary α-Mg phase under the solidification in Mg-Al system alloys. Thus, volume fraction of none-equilibrium crystallized β-Mg17Al12 phase showed the higher value compared with metal mold casting with faster cooling rate. However, in our microstructure observation results, the volume fraction of β phase in permanent mold castings was larger than that of sand mold castings. In the present study, these contradictory behavior was investigated by observation of as-solidified microstructure obtained from rapid cooling castings at the just below the solidus temperature of 723, 773 and 823K.
The Development of Novel Textures in Rare Earth Element Containing Magnesium Alloys
Authors: Majkut M. , Diak Bradley J. , Mackenzie L.W.F.
Published: December 2011

Magnesium (Mg) is a hexagonal close-packed light metal whose deformation re-sponse is characterized predominantly by easy slip on the f0002g basal plane at temperaturesbelow 200°C. Rolled sheet products develop a strong basal texture and become \plasticallychallenged" in subsequent forming operations. In the literature, additions of rare earth ele-ments (REE) to Mg have inconsistently reported non-basal texture formation. In this work,Mg-0.2wt%Gd and 0.2-wt%La were investigated to determine whether the presence of theseelements contributed to non-basal texture formation after elevated temperature plane straincompression. Test specimens were prepared from book-mould castings after homogenization at400°C, and reduced 50% in a channel die at 250, 325, or 375°C and 10-2/s. The stress-strainbehaviours were all characterized by apparent twin-related softening, followed by monotonichardening to the end of the imposed deformation. The yield stress for Mg-0.2%La (15-22 MPa)was higher and less temperature dependent than for Mg-0.2%Gd (10-18 MPa). Texture mea-surements indicate the spread of ideal basal texture about TD with increased temperature, butalso also greater non-basal textures in the Mg-0.2%Gd alloy, particularly at 325°C. Electronchanneling contrast imaging revealed a more re ned and homogeneous substructure in the Gd-containing alloy compared with larger microbands in the La-containing alloy, and suggests thatcontinuous recovery and other available slip systems may contribute to these di erences.
Electrochemical Behavior of Mg-6mass%Al Alloy Corroded in Na2SO4 and NaCl Solutions
Authors: Saito Shunsuke , Sunada Satoshi , Furui Mitsuaki , Ikeno Susumu , Saikawa Seiji
Published: December 2011

The corrosion behavior of Mg-6mass%Al alloy with different microstructure conditions was studied by electrochemical method in Na2SO4and NaCl solutions. A measurement of polarization curves was carried out in order to investigate the fundamental electrochemical characteristics. Electrochemical impedance spectroscopy was carried out to discuss the corrosion characteristics that were obtained from polarization curves. Electrochemical measurements were carried out with as-cast, as solution-treated and two kinds of aged specimens, respectively. For measurement of polarization curves, the apparent difference was exhibited in behavior showing the pitting corrosion by difference of solutions. In all specimens, the corrosion current density which occurred in four kinds of specimens was higher in the NaCl solution than in Na2SO4solution.
Simulation of Phase Transformation by Analysis of First Derivative of Dilatation Using Avrami Equation during Continuous Cooling in Low Carbon Steels
Authors: Park Bong June , Choi Jong Min , Lee Kyung Jong
Published: December 2011

The phase transformation during continuous cooling in low carbon steel has been widely measured by dilatometer using the lever rule. However, the concept of lever rule has several limitations. In low carbon steels, it is observed that overlapped transformation region of multi-phase and inflection point of small amount of low temperature phase is hardly differentiated. First derivatives of LVDT during continuous cooling could be better way to identify the inflection point and transformation region of phases (especially low temperature phase). Furthermore, first derivative of LVDT could be expressed as the lattice parameter and phase fraction due to temperature. Therefore, phase transformation behavior is simulated by the analysis of first derivative of LVDT using Avrami equation from experimental LVDT. As a result, the start, finish temperature and the amount of each phase are determined. The method is also confirmed by OM and SEM.
Influence of Microstructural Inhomogenities on Internal Stress and Strain Distributions during Creep
Authors: Pein Cornelia , Sonderegger Bernhard , Sommitsch Christof
Published: December 2011

The influence of the microstructure of metallic materials on its creep behavior is complex. Besides the chemical composition, the distinct configuration of the microstructural elements has a major influence on the deformation processes. In the presented work a physically based Finite Element model has been applied to study creep behavior on a microstructural level. The main focus is set on the local influence of grain boundaries and triple points on creep straining. The results indicate that such microstructural configurations lead to a highly heterogeneous creep strain distribution. Thus, this study is an important step to a deeper understanding of complex local interactions of creep phenomena.
The Ca-Rich Corner of the Al-Ca-Zn System
Authors: Konica Shabnam , Zhang Yi Nan , Kevorkov Dmytro , Medraj Mamoun
Published: December 2011

In this work, the partial isothermal section of the Al-Ca-Zn system in the region between 33.3 and 100 at.% Ca has been investigated at 350°C using key alloys. The actual composition of the alloys is measured by inductively coupled plasma technique. Phase relations and solubility limits of the binary and ternary compounds have been determined by means of electron probe microanalysis and X-ray diffraction. In the current work, a new ternary compound has been identified in this region with the Al9Ca31Zn10 (IM1) composition. Binary compound Al14Ca13 (IM2) has an extended solid solubility into the ternary system. The homogeneity ranges of the Al2Ca, the MgNi2-type C36 phase Al2-xCaZnx (0.28≤x≤0.70) (IM3) at 350°C and CaZn2 compounds in the pseudobinary Al2Ca-CaZn2 section have been determined at 350°C and the results are combined with the literature to construct the partial vertical Al2Ca-CaZn2 section and partial isothermal Al-Ca-Zn section at 350°C.
Corrosion Behaviour of Nanocrystalline Zn-Ni and Zn-Ni-Co Electrodeposits
Authors: Monaco L. , McCrea J.L. , Palumbo G. , Erb Uwe
Published: December 2011

In this study, alternatives to corrosion-resistant cadmium coatings on high strength steel fasteners are explored. Nanocrystalline Zn-Ni and Zn-Ni-Co electrodeposits, synthesized by electrochemical deposition, were analyzed by potentiodynamic polarization in a 1M NaCl aqueous solution, to determine the corrosion behaviour of the alloys. Sample coatings were characterized using scanning electron microscopy to examine differences in surface morphology that can affect corrosion resistance. Energy dispersive x-ray spectroscopy was used to relate composition to corrosion resistance and to characterize the corrosion behavior during polarization. All coatings showed corrosion potentials at equivalent, or lower values than that of cadmium, suggesting that both alloys are viable as cadmium replacements. Specific compositions showed slightly passivating regions, but the brittle film formed during polarization is unstable. Comparatively, Zn-Ni shows a better resistance to corrosion than Zn-Ni-Co. The effect of composition on the corrosion resistance can be explained on the basis of the sacrificial depletion of Zn over Ni.
Neutron Diffraction Investigations of a CuAlBe Shape Memory Alloy
Authors: Dubois Matthieu , Mathon Marie Hélène , Klosek Vincent , Andre Gilles , Lodini Alain
Published: December 2011

This work was devoted to the study of a copper based shape memory alloy using the neutron diffraction method. We present the crystallographic texture evolution of the austenite phase of the Cu-11%Al-0.62%Be (wt. %) alloy which was subjected to cold and hot rolling processes. The texture of the cold rolled samples at reduction rates of 5%, 10% and 15% respectively was measured and compared to the raw material. A <001> partial fiber is observed for the raw material and for cold rolled samples whereas the texture of the hot rolled sample is mainly characterized by a <111> fiber. On the second part, we have studied the influence of the rolling treatment on the transition temperatures by following the integrated intensity of the {220} austenite reflection. The increase of the rolling rate seems to shift the characteristic temperatures towards low temperatures.
Martensite Variant Reorientation of NiMnGa/Silicone Composites Containing Polystyrene Foam Particles
Authors: Watanabe Yui , Okuno Motoki , Shimizu Yoshinaka , Kanetaka Hiroyasu , Inamura Tomonari , Hosoda Hideki
Published: December 2011

Effect of elastic modulus of matrix on ferromagnetic motion of NiMnGa particles was investigated for NiMnGa particles embedded silicone matrix composites with or without containing polystyrene form particles (PFPs), which are regarded as pores. NiMnGa single crystal was fabricated by a floating zone method and a cube-shape particle was fabricated with the surface orientation parallel to [100], [010] and [001] directions at the parent phase state. The elastic modulus of matrix polymer was controlled by changing the number of PFPs. It was found that the elastic modulus of silicone was decreased with increasing the volume fraction of PFPs. The magnetic-field-induced martensite variant reorientation (MVR) was evaluated by the magnetization curves obtained using a vibration sample magnetometer, and the magnetic field required for the start of martensite variant reorientation was reduced by increasing the number of PFPs. The control of elastic modulus of matrix polymer is important and a dominant factor for the magnetic motion of NiMnGa/polymer composites.
Interparticle Liquid Film Formation during Spark Plasma Sintering of Inconel 718 Superalloy
Authors: Levasseur David , Brochu Mathieu
Published: December 2011

The use of powder metallurgy for near net shape sintering of superalloy could lead to major savings in machining time and material. The main challenge in sintering Inconel 718 is to avoid the formation of a prior particle boundary (PPB) network that is deleterious to the mechanical properties. Using the Spark Plasma Sintering (SPS) technique, it is believed that Inconel 718 powders could be sintered without forming a PPB network due to the fast heating rate achieved and the reported cleaning effect of particle surfaces by the interparticle arc discharges. In this study, Inconel 718 was consolidated to near-full density at 1200°C under 50 MPa of pressure with heating rates ranging from 20°C/min to 800°C/min. The densification behavior of the powder was studied through the analysis of the densification curves and observation of the microstructure evolution from interrupted tests. The fast densification of Inconel 718 in SPS was linked to the formation of a supersolidus liquid phase due to the nature of the heating in this technique.
Formation of Fe-Al Intermetallic Compound Film on Carbon Steel by Shot Peening and Heat Treatment
Authors: Harada Yasunori , Miura Yuji , Takahashi Katsuhiko
Published: December 2011

The formation of an Fe-Al intermetallic compound film on carbon steel by shot lining and heat treatment was investigated. In the experiment, a centrifugal-type peening machine with an electrical heater was employed. The shot medium was high-carbon cast steel. The substrate was a commercial carbon steel, and the sheet was commercially available pure aluminum. The shot lining process of carbon steel with an aluminum sheet was carried out at 300 °C in air using a peening machine. Heat treatment was performed at diffusion temperatures from 600 to 1050 °C in vacuum. The lined substrates exhibited a harder layer of Al-rich intermetallics, such as Fe2Al5, in the diffusion temperature range of 650 to 900 °C. When the temperature of the lined substrates was more than 930 °C, the surface was covered with thicker and highly anticorrosive layers of Fe-rich intermetallics, such as FeAl and Fe3Al. We found that the present method could be used for the formation of functional films on carbon steel.
Vacuum Brazing Porous W and Mo Using Ti-Ni-Nb Braze Alloys
Authors: Lin C.C. , Chen Chun , Shiue Ren Kae , Shy H.J. , Chang C.Steve
Published: December 2011

A novel approach of brazing porous W and Mo using three clad Ti-Ni-Nb foils has been performed in the experiment. Clad Ti-Ni-Nb filler foils are featured with low brazing temperature of below 1350°C. Both W and Mo are completely soluble with β-Ti and Nb, and the Ni addition into the braze alloy is served as a melting point depressant (MPD). Decreased brazing temperature and/or time are necessary in order to minimize infiltration of the molten braze into the porous W substrate. According to the experimental results, Ti-Ni-Nb ternary alloys are promising filler metals in low-temperature brazing porous W and Mo.
The System of Solar Energy & its Key Materials
Authors: Ge Chang Chun
Published: December 2011

Now, over 90% of energy is produced by fossil fuel including coal, oil and natural gas, etc. With the time go on and the same consumption rate of energy, the energy status of world will be more serious. So human being should be finding other cleanness energy in order to meet their need. The solar energy is a promising energy which can be realized in the future most experts believe. Firstly, the concept of SSPS is brought forward in this paper. Additionally, the status of energy consumption and the studying trend of space solar power system (SSPS) are described which comprise the key technologies of SSPS in need. Then the key materials of development of SSPS and some suggestions are presented.
Dynamical Response of Sandwich Plates with Strength Graded Cores to Blast Loading
Authors: Yu B. , Xin Feng Xian , Lu T.J.
Published: December 2011

A one-dimensional analytical scheme is developed for the dynamical response of sandwich plates having strength graded cores to shock impact. Results for in-air blast show that strength gradient distribution affects significantly the dynamic behavior of the sandwich. With fluid-structure interaction (FSI) taken into account, the approach is extended to underwater blast. It is demonstrated that whilst the influence of strength gradient distribution is noticeable on the impulse resistance, it depends strongly upon the core strength and FSI index. A gradient influence factor (GIF) is introduced to quantify the influence of different strength gradient distributions.
Duct Noise Control by Using Very Light Composite Plate
Authors: Choy Y.S. , Liu Yang , Lau Kin Tak
Published: December 2011

A compact flow-through plate silencer is constructed for low frequency noise control by using new reinforced composite plates. The concept comes from the previous theoretical study [1] that in a duct, a clamped supported plate covered with a rigid cavites. The structural property of the very light plate with high bending stiffness is very crucial element in such plate silencer. In this study, an approach to fabricate new reinforced composite panel with light weight and high bending stiffness is developed in order to realize the function of this plate silencer practically. The performance of two plate silencer with the stopband from 229 to 618Hz in which the transmission loss is higher than 10 dB over the whole frequency band can be achieved.
Characterisation of Energy Generating PolyVinylidene Fluoride (PVDF) Based Piezoelectric Filament
Authors: Vatansever D. , Hadimani R.L. , Shah T. , Siores E.
Published: December 2011

Polyvinylidene Fluoride (PVDF) Is Not Inherently Piezoelectric however Non-Piezoelectric α-Crystal Form of the Polymer Can Be Transform to Piezoelectric β-Crystal Form by Application of High Drawing Ratio, Heat and High DC Voltage. in this Work, some Mechanical Tests, such as Linear Density, Tenacity, Elongation%, Were Carried Out to Comparatively Investigate both Poled and Unpoled PVDF Filaments which Were Produced via a Continuous Process in a Customized Melt Extruder. the Voltage Responses of Poled and Unpoled Filaments Were Also Investigated under a Standard Impact Test Ring. These Filaments Were then Studied under Semi Electron Microscopy (SEM) for their Micro Structural Analysis.
A Comparative Study on Conventional Electrospinning and Emulsion Electrospinning of PLLA Nanofibers
Authors: Zhang Xin , Wang Min , Yuan Xiao Yan , Kang Jia Chen
Published: December 2011

Electrospinning is investigated by many groups around the world for constructing fibrous tissue engineering scaffolds. Incorporating biomolecules such as growth factors in fibers is becoming common for enhancing the biological performance of electrospun scaffolds. However, biomolecules may lose bioactivity if they are exposed to organic solvent during electrospinning. In emulsion electrospinning, an aqueous biomolecule solution is emulsified and water-in-oil emulsions are then electrospun into core-shell structured fibers, with biomolecules being contained in the core of fibers, which helps to avoid biomolecule-solvent contact and also reduce the initial burst release. In this investigation, for a comparative study, poly (L-lactic acid) was made into solid and core-shell structured fibers via conventional electrospinning and emulsion electrospinning, respectively. The two electrospinning techniques and resultant fibers were compared in terms of processing parameters (polymer concentration, applied voltage, working distance, etc.) and fiber characteristics (morphology, diameter, structure, etc.). Solvent properties such as conductivity and volatility affected fiber morphology and diameter. The polymer concentration range usable for emulsion electrospinning was narrower than that for conventional electrospinning owing to changes in viscosity.
Emulsion Electrospinning of Nanofibrous Delivery Vehicles for the Controlled Release of Biomolecules and the In Vitro Release Behaviour of Biomolecules
Authors: Wang Chong , Wang Min
Published: December 2011

Electrospinning is a popular technique for constructing nanofibrous tissue engineering scaffolds. Electrospinning is also amenable to the incorporation of drugs or biomolecules in fibers, which can provide local and sustained delivery of biological signals, such as growth factors, for the seeded cells. Drugs can normally be dissolved in polymer solutions for electrospinning, forming nanofibrous drug delivery systems. However, simply blending biomolecules in polymer solutions can result in denaturation of biomolecules and large initial burst release. Therefore, emulsion electrospinning, which can provide protection for biomolecules during electrospinning, is of great interest. In this investigation, biomolecule-containing scaffolds were emulsion electrospun using bovine serum albumin (BSA) as the model protein. Two polymers, poly (lactic-co-glycolic acid) and poly (D,L-lactic acid), were used due to their different degradation characteristics. Nanofibers with core-shell structures were electrospun from water-in-oil emulsions formulated by polymer solution, BSA-containing deionized water and a surfactant. By changing the polymer concentration and water phase volume, the fiber diameter and core-shell structure were varied. With different polymers and different fiber structures, the in vitro BSA release behaviours from fibrous scaffolds were different.
Fabrication of Bi-2223 Powders Using Sol-Gel Method
Authors: Li Ming Ya , Wang Xiao Yan , Ye Cheng Li , Xue Feng Lin
Published: December 2011

The Bi-2223 powders were fabricated by the sol-gel technique. Metal nitrates were used as starting materials, and ethylenediamineteracetic acid was used as chelating agent. The solution was heated until it turns to gel. Then the organic was removed at a temperature of 240°C, and the nitrite was removed at 500°C. The powder was calcined at different temperature, varying the dwelling time. Experimental results show that the main phase of samples after heat treatment is Bi-2212 phase.
Preparation and Characterization of Fused Silica Micro-Powders and Ceramics
Authors: Niu Jin Ye , Chen Zhi Wei , Feng Liu , Li Zheng Min , Tan Min
Published: December 2011

Fused silica micro-powders with D50of 1.8μm were firstly prepared by ball milling. Effects of milling time on particle size distribution and microstructures of the powders were discussed. Then, the green compacts with volume density of 1.86g/cm3was obtained by slip casting with lactic acid as dispersant. Effects of lactic acid content on apparent viscosity of the slurry, thickness and density of the green compacts were investigated. Finally, fused silica ceramics with thermal expansion coefficient of 0.56∙10-6/°C, bending strength of 64MPa and volume density of 1.94g/cm3were prepared.
Preparation and Characterization of Meso-Porous Alumina Spheres
Authors: Chang Qi Bing , Wang Xia , Zhou Jian Er , Wang Yong Qing
Published: December 2011

Mesoporous alumina is usually used as adsorption material, catalyst carrier or separation media due to its high adsorption and good thermal stability. However, the nanosized powder trends to aggregation except that its size is in sub-micron scale. The best choice is that the sub-micron alumina particles with mesoporous structure are prepared. In the present work, the mesoporous alumina spheres were prepared by micro emulsion method using aluminium isopropoxide as raw material and water/dimethylbenzene emulsion as reaction media. The obtained powder was characterized by XRD, TEM and BET. The results show that the particles are global. The particles size is in the range of 100 ~ 200 nm to several micrometers. The particle owns the worm-like structure with the pore size of 5 nm. The BET surface area of the mesoporous alumina is 81.8 m2/g. The obtained powder is suit to be used as the packing material in chromatograph.
Iron-Zircon Pigments Prepared by Non-Hydrolytic Sol-Gel Method at Low Temperature
Authors: Jiang Wei Hui , Yang Yan Hui , Zhu Qing Xia , Liu Jian Min
Published: December 2011

ron-zircon pigment has been synthesized by non-hydrolytic sol-gel method using zirconium chloride and tetraethoxysilane as precursors, anhydrous ferric chloride as colorant, lithium fluoride as mineralizer and anhydrous ethanol as solvent. Iron-zircon pigment has been characterized by means of DTA-TG, XRD, Colorimeter and TEM. The results show that only a small fraction of iron is incorporated in the zircon crystal structure while the remaining iron cations are trapped within the zircon matrix. The iron-zircon with the red value (a*) of 20.64 can be synthesized at 700°C with the optimum Fe/Zr molar ratio of 0.2.
Nano-Au/C Catalysts for the Selective Oxidation of Glucose into Gluconate
Authors: Li Zi Jing , Huang Du Shu , Liu Wei , Xiao Rui Min , Liu Jie , Xu Chun , Jiang Yan , Sun Li Da
Published: December 2011

Au/C catalyst used for the liquid phase selective oxidation of glucose to gluconate was prepared by gold sol method that includes the preparation of metallic colloid by citrate reduction and subsequent immersion by carbon support. The influence of gold particles of different size on the activity of Au/C catalyst was studied. The results show that the catalyst with good dispersed spherical gold particles has higher catalytic activity. After 16 runs, the conversion of glucose selective oxidation can still achieve over 96% under mild reaction conditions.
Effects of AgNO3 Concentration on the Preparation of Nano-Silver
Authors: Zhai Feng Rui , Yi Zhong Zhou , Zhang Hong Wei
Published: December 2011

nanosilver powder has high surface activity, catalysis property and wide usage, so it is important to study its preparation method. In this paper, nanosilver powder was prepared with industrial AgNO3 as raw materials, hydrazine hydrate as the reducing agent, polyvinylpyrrolidone (PVP) as the polymeric protective agent, polyethylene glycol as the dispersing agent by solution chemical reduction method. The effects of AgNO3 concentration on the preparation of nanosilver were studied, and the final product was examined with TEM testing. The test results show that it can be obtained flake nanosilver with good performance by controlling the reaction conditions, such as dispersion, stability and crystal properties.
Preparing Flake Silver Powder by High-Energy Ball Milling
Authors: Zhang Lei , Gan Guo You , Yan Ji Kang , Du Jing Hong , Zhang Jia Min , Yi Jian Hong , Wu Quan , Zheng Ya
Published: December 2011

Using the high-energy ball milling craft, the case that the silver powders’ changes along the condition of ball milling is researched by the orthogonal experiment methods, the laser particle analyzer and the scanning electronic microscope. The influences of the milling times, the dispersant agents, speed and ratio of ball to powder on the distribution of particle size, the shape of grain and the specific surface are studied. The results show that, by using the composite dispersant agent, milling for 20h,ethanol as grinding aids and calcium stearate as dispersing agent, powders of average diameter is 8.55μm and specific surface area is 0.67(m2/g), with higher laminarization and less reunion of ultrafine flake silver powders.
Preparation of Micro-Sized Silver Powder Utilized in Paste for Solar Cell Grid Electrode
Authors: Zheng Ya , Gan Guo You , Zhang Lei , Yan Ji Kang , Du Jing Hong , Zhang Jia Min , Yi Jian Hong
Published: December 2011

The micro-sized silver used for solar cell grid electrode was obtained from silver nitrate via chemical reduction under ultrasonic wave and alkaline environment using polyethylene glycol (PEG-6000) as dispersant and alcohol as surfactant, and after agitation, the sol was filtered, washed and dried at constant temperature. The PEG and alcohol protective mechanism in the preparing process of spherical silver particles was studied. Effects of the amount of dispersant, pH, dosage of alcohol, were investigated. The silver powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Results show that with 0.35mol/LAgNO3 solution, 25mL ethanol, T = 40°C, pH = 8 and 10min ultrasonic wave, spherical silver power about 1.38 ~ 2.11μm with narrow particle size distribution was fabricated. The paste prepared with ready-made silver powder was printed on the silicon and the contact resistance is very low, indicating the electrical property of the prepared silver is qualified for solar cells.
Effect of Low-Temperature Frit on the Sintering Behavior and Properties of 0.95K0.49Na0.51NbO3-0.05LiSbO3 Lead-Free Piezoceramics
Authors: Wang Zhu Mei , Li Yue Ming , Li Run Run , Shen Zong Yang , Hong Yan
Published: December 2011

The effects of low-temperature frit Li2O-Na2O-K2O-B2O3-SiO2-CaO-BaO-ZnO (abbreviated as BS) on the sintering behavior and electrical properties of 0.95K0.49Na0.51NbO3- 0.05LiSbO3 (abbreviated as KNN-LS) lead-free piezoceramics were investigated. The sintering temperature of the KNN-LS ceramics can be reduced from 1080 °C to 1000 °C due to the addition of BS frit. For the 0.5 wt% BS-doped KNN-LS ceramics, which are sintered at reduced temperature of 1000 °C for 2 h, remain relatively high piezoelectric constant d33 (195 pC/N) and planar electromechanical coupling coefficient kp (40.7%). In addition to other optimization effects, such as reduction of dielectric loss from 3.6% to 2.7% and increment of mechanical quality factor Qm from 48 to 70, this BS frit was experimentally proved to be good for low temperature sintering of KNN-based ceramics while maintaining high piezoelectric response.
Ferroelectric Properties and Microstructures of La2O3-Doped Bi4Ti3O12 Ceramics
Authors: Huang Chong Qing , Chen Min , Mei X.A. , Sun Y.H. , Liu J.
Published: December 2011

The electrical properties of La-doped bismuth titanate, Bi4-xLaxTi3O12(BLT) ceramics prepared by a conventional electroceramic technique have been investigated. XRD analyses revealed Bi-layered perovskite structure in all samples, and indicted that Bi ions were only substituted near the Ti-O octahedron layers by La ions. SEM micrographs show randomly oriented and plate-like morphology. The remanent polarization ( Pr) and coercive field ( Ec) of the BLT ceramic with x=0.75 were above 19μC/cm2and 60KV/cm, respectively. The large value of remanent polarization and low coercive field of La-doped bismuth titanate ceramics promote these materials to potential applications.
Study on (n+n) Type Acetone Gas Sensor
Authors: Yang Liu Fang , Wang Yu Lin , Liu Han Zhe , Luo Xiao Qing
Published: December 2011

(n+n) structure semiconductor gas sensor based on the compensation-feedback principle is composed of two sensitive materials A and B which are all n-type materials. The results analyzed from a theoretical viewpoint show that the (n+n) combined structure semiconductor gas sensor has higher selectivity, better thermal stability and higher sensitivity than conventional sensors when the materials A and B satisfied certain conditions. Though testing the characteristics of the (n+n) combined structure semiconductor gas sensor, the perfect (n+n) combined structure acetone gas sensor is fabricated, and could be applied to monitor and control leakage of acetone gas.
Microstructures and Properties of Woodceramics Prepared from Bagasse and Epoxy Resin Composite
Authors: Zhang Cheng Hua , Pan Jian Mei , Yan Xue Hua , Cheng Xiao Nong , Xu Gui Fang , Gao Yong Quan
Published: December 2011

A porous biomorphic woodceramic was prepared from bagasse powders infiltrated with the epoxy resin followed by sintering in vacuum. The microstructures and chemical structures of the woodceramics were studied by SEM and FTIR, respectively. The effect of the sintering temperature and content of bagasse on the carbon yield ratio, volume shrinkage ratio, and volume electrical resistivity of the woodceramics were studied. Experimental results show that the pores in woodceramics present the irregular distribution but the main structural features of the tracheidal cell structures are retained. The woodceramic is a carbon material containing C–O–C, C=C, C=O and C–H bonds. The carbon yield ratio of the woodceramics decreases with the increase of the content of bagasse. While the volume shrinkage ratio and volume electrical resistivity increase with the increase of the content of bagasse.
Synthesis and Characterization of 3Y-TZP by Gel Solid-State Method
Authors: Wu Xiao Bo , Sun Da Zhi , Jiang Dan Yu , Xu Hai Fang , Huang De Xin , Xu Bing
Published: December 2011

3Y-TZP powder has been successfully synthesized by gel solid-state method. The structural phases of powder particles were analyzed by X-ray diffraction and the morphology was analyzed by scanning electron microscopy. The average size of grains was 230 nm. The sintering behavior, mechanical properties and microstructure of 3Y-TZP ceramics sintered by this powder were investigated. The experiment results showed that the mechanical properties of ceramics were excellent.
Preparation and Properties of the ZnO Nanopowder with Chemical Liquid-Phase Method
Authors: Yi Zhong Zhou , Wang Bo , Zhai Feng Rui , Xie Zhi Peng
Published: December 2011

ZnO nanopowder have been prepared by chemistry liquid-phase method with the water soluble polymer and the surfactant as additive in [Zn (OH)4]2- precursor solution. The Character of spectroscopy and microstructure and phase composition was studied by X-ray diffraction, transmission electron microscopy and UV–Vis absorption spectroscopy. The possible influence like reaction time, reaction temperature, reactant ratios and so on was investigated. At the same time, the inorganic granule coring and the crystal growth affected by the water-soluble polymer and the surfactant were discussed. Studies have shown the ZnO nanopowder with the diameter of 50nm has the structure such as the good crystal state and well-defined crystallographic surfaces. The ZnO nanopowder have strong absorption in the UV region with the wavelength of 200 ~ 300 nm.
Preparation of ZnNb2O6 Powders by Molten Salt Method
Authors: Zhang Dai Bing , Gan Guo You , Yan Ji Kang , Chen Zhong Wen , Du Jing Hong , Yi Jian Hong
Published: December 2011

ZnNb2O6powders were prepared by solid phase method and molten salt method. KCl-NaCl-ZnCl2was used as molten salt. The mass ratio of molten salt and raw material is 1:1. Pure ZnNb2O6powders were synthesized by molten salt method? at 650°C, which was reduced by 200°C relative to solid phase method. ZnNb2O6powders preferably grow along special direction, and appear strip or rod like. ZnNb2O6powders calcined at 650°C have narrow particle size distribution. Median size D50 =5.31μm. With the increase of the calcining temperature grain grows and particle size increases.
Study of Depth-Dependent Tetragonal Distortion of GaN Epilayer with Tri-Layer AlGaN Interlayer Growth on Si(111)
Authors: Ding Bin Feng , Chai Yong Quan
Published: December 2011

A GaN epilayer with tri-layer AlGaN interlayer grown on Si (111) by metal-organic chemical vapor deposition (MOCVD) method was discussed by synchrotron radiation x-ray diffraction (SRXRD) and Rutherford backscattering (RBS)/C. The crystal quality of the epilayer is very good with a χmin=2.1%. According to the results of the θ-2θ scan of GaN(0002) and GaN(1122), the epilayer elastic strains in perpendicular and parallel directions were calculated respectively to be-0.019% and 0.063%. By the angular scan using RBS/C around a symmetric [0001] axis and an asymmetric [1213] axis in the (1010) plane of the GaN layer, the tetragonal distortion (eT ) were determined to be 0.09%. This result coincides with that from SRXRD perfectly. The strain decreases gradually towards the near-surface layer, which will avoid the film cracks efficiently and improve the crystal quality of the GaN epilayer remarkably.
Research on Compression and Bending Resistance Characteristics of Logs
Authors: Yang Xue Chun , Luo Ju Ying
Published: December 2011

The testing experiments to healthy poplar and larch logs samplings were conducted by using hydraulic machine. The relationships among compression and bending strength, modulus of elasticity in compression and bending were studied in the two logs samplings. The results indicated that, in the both species, the compression strength had certain linear correlation with bending strength, and so did the modulus of elasticity in compression and bending. Meanwhile there were remarkable linear correlations with the compression strength and the modulus of elasticity in compression as well as the bending strength and the modulus of elasticity in bending.
Fuzzy Logic Modeling of Porous Carbon Body Fabrication from Cellulose Based Materials
Authors: Vafaeenezhad Hossein , Zebarjad Seyed Mojtaba , Khaki Jalil Vahdati
Published: December 2011

This research presents a novel process for dry wood parts carbonization to net shape porous carbon body which retains all the wood’s anatomical feature. Due to reasonable price, easy shaping and good formability of wood, as a raw material, it can be used in several advanced cellulose-based applications without any special finishing steps. The interpretation of how carbonization parameters such as heat treatment temperature, carbonization time and initial density of wood affects the final solid carbon characteristics is a fundamental step in this technology improvement and is discussed in this study. A fuzzy logic (FL) method was implemented as a powerful and accurate way for predicting the bulk density change in special tree wood samples during carbonization process. Besides, a regression relationship is established between above parameters and subsequently, significance of each one was identified. Scanning electron microscope (SEM) was used to elucidate the porous carbon microstructure of final product.
Nitrogen Concentration in N-Implanted Gold on the Formation of Gold Nitride
Authors: Yang Jian Hua
Published: December 2011

Although gold nitride has been produced by Siller and co-workers by irradiating a gold film with low energy nitrogen ions, the unsuccessful reason for previous attempts to produce gold nitride is not clear yet. In general, nitrogen concentration depth profile probably influences gold nitride formation. But it is difficult to measure nitrogen concentration depth profile in the N-implanted layer at a low implantation energy of 500 eV. Ion concentration depth profiles in amorphous solids can be determined rather accurately in the case of low implantation fluences using TRIM code. The sputtering effect of ion implantation of high fluences on the concentration depth profile of implanted nitrogen ions should be considered. A dynamic computer simulation based on a TRIDYN code has been applied to calculate nitrogen concentration depth profile in a N-implanted gold film using the different parameters of the fluence and energy in the present work. The sputtering effect of a high fluence on the concentration depth profile can be considered in the TRIDYN simulation. The parameters of fluence and energy that enable to get the gold nitride in thin film are analyzed based on the simulation results. It is put forward some possible ways to improve the formation of gold nitride further.
Relativity Analysis on the Detection Methods of Compaction Degree for Expressway Subgrade
Authors: Zhao Gui Juan
Published: December 2011

A test section was selected in Luo-San expressway.Four detection methods of compaction degree which are sand cone method, cutting ring, nuclear density instrument and drop hammer frequent mensuration£¨LY-1 apparatus£©have been adopted in testing road.And the detection results about four methods were analyzed and compared.Sand cone method was conducted as a standard method of field detection for compaction degree, other three methods were regressed with sand cone method,and the relationship was obtained. The relevance of cutting ring method with sand cone method is excellent,the relevance of other two methods with sand cone method is slightly bad which may because of the soil and construction methods.But in general, it is approved that sand cone method method which act as the standard one of detection for compaction degree is worthwhile extending.