bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Size Control of Monodisperse Silica Sol Nanospheres via a Modified Stöber Method
Authors: Li Jie , Chen Lian Xi , Zhang Zhong Ming , Jiao Cai Bin
Published: August 2012

An effective and optimized method for synthesis silica sol nanospheres by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in the presence of aqueous alcohol solution with ammonia as catalyst was described. Under this experiment condition, monodisperse and uniform-size silica sol spheres with average diameters from 38-95nm were obtained. Here, we successfully controlled the size and shape of silica sol by fine adjusting the reaction parameters such as concentration of TEOS, value of R (H2O/TEOS) and ammonia concentration. On the basis of the experiment results, it was found that sphere size declined as the concentration of TEOS decreased. Also with the increment of ammonia concentration, the diameter of silica sol decreased slightly. However, higher R (H2O/TEOS) value would lead to larger sphere size in the range of 62-95nm. The resulting silica sol was determined by Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier transformed infrared (FT-IR).
Hemicellulose-Based Porous Hydrogel for Methylene Blue Adsorption
Authors: Jing Zhan Xin , Sun Xiao Feng , Ye Qing , Li Ya Jing
Published: August 2012

Hemicellulose-based porous hydrogel for methylene blue adsorption from aqueous solution was studied. The surface morphology of sample was analyzed by SEM, finding that it had the porous structure. Effects of pH and initial concentration on the adsorption capacity were investigated. Isotherm studies found that the adsorption of metylene blue onto absorbent was a monolayer adsorption, and the maximum adsorption capacity was 444.44 mg/g. The adsorption mechanism was analyzed by FT-IR, and it showed that the produced -COO- groups in alkaline conditions were advantaged for adsorption process, which offers the impetus for combination of adsorbent and methylene blue. Hemicellulose-based porous hydrogel is an inexpensive and biodegradable material, and can be a promising absorbent for cationic removing from wastewater.
Effect of Electrochemical Synthesis Conditions on Capacitor Performance of Polyaniline Electrodes
Authors: Wang Hua
Published: August 2012

Abstract: Polyaniline was electrochemically synthesized on stainless steel using sulfuric acid as the doping agent through cyclic voltammetry. The influences of the aniline monomer concentration and cycle number on electrochemical performance were investigated by cyclic voltammetry and the electrochemical impedance spectra. The results show that increasing aniline concentration leads to the increase of aniline electrochemical polymerization rate. The mass specific capacitance of polyaniline electrode increases with the increase of aniline concentration for 10 cycles and it reaches 769.55 F/g at the aniline concentration of 0.3mol/L. However, the capacitances of polyaniline prepared at different aniline concentrations display no apparent differences for 15 or 20 cycles. Furthermore, the capacitance decreases with the increase of cycling number. Electrochemical impedance spectroscopes show that the polyaniline keeps superior conducting performance in the potential range of 0.1V~0.4V
Calcium Doping Effects on the Electrochemical Properties of LiFePO4/C Cathode Materials for Lithium-Ion Batteries
Authors: Fey George Ting Kuo , Yan Cyun Jhe , Lin Yi Chuan , Huang Kai Pin , Cho Yung Da , Wu Pin Jiun , Sun Ya Sen , Kao Hsien Ming
Published: August 2012

This Olivine LiFe1-xCaxPO4/C composites (x=0 - 0.014) were synthesized by a solid-state method using sebasic acid as a carbon source. The structure and electrochemical properties of the LiFe1-xCaxPO4/C compounds were studied. The X-ray diffractometer (XRD) results indicated that Ca2+ doping did not affect the structure of the samples, but the unit cell volume of doped sample are slightly increased. Electrochemical measurements showed that the LiFe0.99Ca0.01PO4/C composite delivered a discharge capacity of 149 mAh g-1 at a 0.2 C-rate between 4.0 and 2.8 V, probably due to the significant improvement of electronic conductivity and Li+ ion diffusion. Besides, the cell can sustain a 20 C-rate, and this rate capability is equivalent to charge or discharge in 3 min.
The Impact of Offset Paper on Ink Transfer Rate and Ink Absorption Rate
Authors: Li Zhi Jian , Meng Qing Jun , Liu Liang
Published: August 2012

The ink transfer rate and ink absorption rate directly affects the quality of printing matter, so it is very important to know the influence factors of the ink transfer rate and ink absorption rate. This paper studied on the impact of offset paper smoothness and offset paper absorbency on the ink transfer rate, the impact of offset paper compactness and offset paper absorbency on the ink absorption rate. The results show that ink transfer rate is affected by offset paper smoothness within a certain range. The ink transfer rate is affected greatly by offset paper absorbency. The ink absorption rate is greatly affected by offset paper compactness and absorbency.
Spark Mixtures for Fireworks
Authors: Beliakov Alexander , Shibanova Anna , Ilyasov Rustam
Published: August 2012

As a result of the carried out complex researches the basic laws of burning and achievement of special effect sparkling mixtures are established, the technique of definition sparkling characteristics is tested by a photographic method, results on improvement of a compounding of mixtures for equipment of products of garden fireworks are submitted.
Response Surface Methodology (RSM) for Wastewater Flocculation by a Novel (AlCl3-PAM) Hybrid Polymer
Authors: Dawood Ammar Salman , Li Yi Lian
Published: August 2012

In this study, a novel aluminum chloride-ploy(acrylamide) hybrid polymer has been synthesized by free radical solution polymerization of acrylamide (AM) onto aluminum chloride (AlCl3) in the presence of ammonium persulphate and sodium hydrogen sulphite as polymerization’s initiators. On the other hand, the structure of hybrid polymer (AlCl3-PAM) has been characterized by Fourier transform infrared spectroscopy (FTIR). The central composite design (CCD) and response surface methodology (RSM) have been applied in the flocculation process of wastewater treatment to achieve maximum removal efficiencies of total suspended solids (TSS), turbidity , and chemical oxygen demined (COD), as the other objectives of this study. The operating variables in this experiment were new hybrid polymer dose and wastewater pH. The maximum conditions have been found to be wastewater pH 7, and hybrid polymer dose 100 mg/l. Under these optimal conditions, the removal of turbidity, TSS, and COD in the effluent have been reached to 98.2%, 99.1%, and 90.6% respectively. According to these results, domestic wastewater treatment using (AlCl3-PAM) has proved to be an effective alternative in the administration of COD, TSS, and turbidity problems of municipality wastewater.
Flame Retardant Epoxy Resins Containing Bisaryl Diphosphates Oligomer
Authors: Gao Ming , Sun Chun Feng
Published: August 2012

Bisphenol A bis( diphenyl phosphate) oligomer (BDP) as flame retardants (FR) was synthesized, whose structure was characterized by IR. 30% weight BDP was doped into epoxy resins (EP) to get 26.2 % of LOI and UL 94 V-0. The degradation behavior of EP containing BDP was studied by TG, SEM and cone calorimeter. In the thermal degradation of EP containing BDP, the initial decomposition temperature, Tm and heat release and smoke production are decreased while Rmax, char yields, and inherent thermal stability are increased. Surface of the char is dense and compact, which can isolate the transfer of mass and heat between the materials and the flame to protect the unburned materials.
Synthesis and Properties of Lightweight Geopolymer using Ash from Thermal Power Plants
Authors: Bogdanov Bogdan Iliev , Hristov Yancho , Georgiev Dimitar Petrov , Markovska Irena
Published: August 2012

A lightweight inorganic polymer is obtained using ash from thermal power plants, metakaolinite and lightweight aggregate. This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. Processing parameters and various curing conditions, such as curing temperature, curing time and moisture, are investigated. Compressive strength, rate of water absorption and density of each sample were measured.
Preparation of SiO2/PEG Shear Thickening System by Centrifugal Dispersion
Authors: Yang Biao , Wang Sheng , Xu Guo Zhi , Xin Fei
Published: August 2012

The nano-SiO2/polyethylene glycol (PEG) dispersion system was prepared by centrifugal mixing, and its rheological properties were investigated. The results showed the revolution and rotation speed during the centrifugal mixing have a significant effect on the rheological properties of SiO2/PEG system. When the revolution speed of the centrifugal mixer was fixed at a high speed of 1200rpm, the shear thickening effect of SiO2/PEG was gradually increased with the decrease of rotation speed, and the maximum viscosity (η) of 12340 mPa•s appeared at the rotation speed of 200 rpm. At the low revolution speed of 700 rpm, the increase of the rotation speed significantly enhanced the shear thickening effect. When the rotation speed was 700rpm, the maximum viscosity was up to 86130mPa s. In steady state experiments, the systems show a shear-thinning property under low shear rate. When the shear rate exceeded a critical value (γ= 24.92 s-1), the viscosity first increased, and then decreased sharply. In the dynamic experiments, with the increase of angular frequency (ω), the loss modulus (G″) also increased and the systems behaved as a shear-thickening fluid.
Study on Properties of Porous Ecological Concrete for Plant-Growing in China
Authors: Li Zheng Qi
Published: August 2012

Porous ecological concrete for plant-growing is a new kind of concrete materials. Its porous texture provides living space for some vegetation’s roots. Because of this, porous ecological concrete can harmonize engineering constructions and environment protections well. The current research situations and engineering applications of this kind of concrete in China are introduced. Both the properties and influencing factors of its physical and mechanical behavior, alkali feature and durability are analyzed. Most of the researches prove that porous ecological concrete surly has broad developing prospect.
Investigation on the Effect of Properties of the Filler on the Efficiency of the Separation of Water-Petroleum Emulsions
Authors: Markovska Irena Georgieva , Bogdanov Bogdan Iliev , Zaitcev Nikolai Konkordievich , Georgiev Dimitar Petrov , Hristov Yancho
Published: August 2012

Abstract. The aim of the present paper is to select suitable filtering material which would be effective for the separation of the aqueous petroleum emulsion. Furthermore, the paper discusses the principles and conditions for separation using filtering materials of different natures. During the experiments, the influences of several factors on the degree of separation were studied: 1) filler material 2) period of contact between emulsion and filler (by varying the model emulsion feeding rate and reactor size) 3) emulsion flow direction through the reactor (to study the effect of gravitation during separation). The experiments were performed with a cylindrical reactor. It was found that the effective separation of water and petroleum requires periods of contact between the emulsion and the filler. Besides, filler should have both hydrophilic and hydrophobic properties.
Methods for Improving Slurry Ability of Yangchangwan Bituminous Coal
Authors: Li Mei , Bao Sheng Fu , Qiu Li Feng
Published: August 2012

Yangchangwan (YCW) bituminous of Ningxia is a weakly reductive coal, which was characterized with low ash content, low sulfur content, low H/C and ash fusion, but high moisture, oxygen, inertinite and alkaline earth metal contents, also difficult to make slurry. Influence of dispersant kind and dosage on YCW CWS rheological behavior was studied using 8 dispersants. Examination was conducted in the lab. The results show that the dispersant and its dosage not only influence the apparent viscosity but also the rheological behavior of CWS. Methyl naphthalene acid salt formaldehyde condensation(MF) is the best dispersant for YCW bituminous coal and the optimal dosage is 1%. CWS were also prepared using compounded dispersants of sodium lignosulphonate and Methyl naphthalene acid salt of formaldehyde condensation and in order to investigate the slurry ability of CWS with compounded dispersants. The results show that compounded dispersants have a greater impact on the liquidity and stability of CWS, the optimal ratio of two dispersant is 3:7. Slurry technologies of blended coals were also studied in this paper, YCW bituminous coal with lower slurry ability , lower static s stability and poor theological behavior and Dafeng(DF) anthracite coal with good properties of CWS and the better theological behavior. The effect of the ratios of two coals on the static stability and viscidity of CWS was studied. The results show that CWS is better static stability ability and viscidity when the chemical additive quantity is at 1 parts per hundred and the ratio of two coals is 3:7.The effects of coal blending on the features of coal-water slurry are nonadditivity. It can effectively improve the concentration of coal water slurry, for coal which has difficulty in preparing coal-water slurry.
The Application Research of Concentration & Denitration Technology in Advanced Reprocessing Process
Authors: Li Yong , Liu Xue Gang , Chen Jin
Published: August 2012

The proper management of spent fuel arising from nuclear power production is a key issue for the sustainable development of nuclear energy. While conventional reprocessing process, PUREX process, was successful to recover uranium and plutonium, in recent years some countries have turned to focus on advanced reprocessing process, which features of partitioning of minor actinides (MA) and long-lived fission products(LLFP). Most advanced reprocessing processes under development involve new extractants and additional extraction cycles. In China, TRPO extraction process has been developed to partition MA/LLFP from high-level liquid waste(HLLW) since early 1980’s. In parallel to R&D work on separation technologies, studies on concentration & denitration process have been evolved to prepare feed solutions to suit qualifications of extraction. Industrially, concentration & denitration is the internationally recognized standard to treat HLLW released from PUREX before vitrification. It enables to minimize the volume of interim storage, to restrain the corrosion of storage tank, to recover nitric acid in HLLW and to reduce the required evaporation duty of the vitrification process. Generally, the constitution of concentrated HLLW has little impact on the following vitrification process. But when concentration & denitration acts as pretreatment process of partitioning, the composition of actinides, fission products, and nitric acid in concentrated HLLW solution plays significant role in extraction process. A series of technical issues relevant to the connection between concentration ﹠denitration and extractions should be solved. This paper describes current status of concentration & denitration technology utilized in industry and under reprocessing plants. The specific separation requirements in advanced reprocessing process and challenges to apply concentration & denitration process are addressed. Besides, concentration & denitration process was tested in laboratory to adjust feed solutions for TRPO and Cyanex301 partitioning. Results demonstrate its promising prospect in advanced reprocessing process.
Study on the Photoelectric Properties of CdSe/MS Composite Film and its Potential Application in Biosensor Field
Authors: Wang Ping , Cheng Li Hua , Zhou Ru Jin
Published: August 2012

CdSe nanocrystals were prepared within a template of mesoporous silica (MS) spheres via chemical reaction. The photocurrent of CdSe/MS composite under UV illumination was distinctly higher than that in the dark. The horseradish peroxidase (HRP) was immobilized on the surface of the composite particles. The HRP/CdSe/MS composite film toward the reduction of hydrogen peroxide (H2O2) had stronger response signal under UV illumination than that in the dark. The electrons photo-generated from CdSe and the electrons provided by electrode can occur simultaneously to catalyze the reduction of H2O2. The holes photo-generated by CdSe are trapped at the interface between CdSe and pore walls of MS film. The results show that CdSe/MS composite film has good photoelectric properties and potential application on immobilization of horseradish peroxidase for hydrogen peroxide monitoring.
Shear Property of Pb-Free Solder Joint According to Temperature Condition by SP and FEM
Authors: Lee Gyun , Yu Hyo Sun , Yang Sung Mo , Kang Hee Yong , Hong Dong Pyo , Song Joon Hyuk
Published: August 2012

The use of Pb-free solder alloys are just newly developed materials and their properties are not well established and documented yet. So, the research to substitute the critical problem of the Pb solder alloy are increasing widely. To evaluate the shear property of solder joints according to temperature condition was predicted through the Shear-Punch test and FEM. By using the database according to this, the reliability evaluation technology of the solder joints tries to be formulated. In this paper, the solder used the Sn37Pb, Sn-4Ag and the Sn4Ag0.5Cu. When solder melted in the copper interface, the solder joints according to reflow times, each modeling required for the Shear- Punch was made in consideration of the IMC layer thickness. And the micro shear punch test was performed to obtain material properties of solder according to temperature condition. The shear properties of specimen which was modeled was predicted through FEM. It compared with the test value in which it obtains from Shear-Punch. Also, a method which can obtain shear properties of Pb-free solder joints easily and quickly using FEM was proposed.
Size and Shape Separation of Ag Nanoparticles by a Continuous Density Gradient Centrifugation
Authors: Li Si Fang , Zhang Hai Yan , Lin Jian
Published: August 2012

In order to get highly monodispersed nanoparticles, a post-synthesis separation of nanopaticles polydisersed in size and shape is often desired, although the experimental conditions for the synthesis of nanoparticles are carefully controlled. Using continuous density gradient centrifugation, Ag nanospheres, nanocubes, and nanowires can be separated from polydisperse samples. Size and dimension analysis by sanning electron microscopy and absorption spectroscopy prove that density gradient centrifugation is a powerful method to obtain monodisersed nanoparticles.
Modeling of Nitrogen Adsorption Process in a 5A Zeolite Pellet
Authors: Liu Xiang Jun , Wang Dan Li
Published: August 2012

A zeolite pellet is formed by binding large numbers of small crystals with microporous material. The adsorption properties of a zeolite pellet depend on its micro-structure. In this paper, two physical models of a 5A zeolite pellet with the crystals dispersed or clustered are established. Mathematical models to describe nitrogen diffusion and adsorption occurred inside the pellet are proposed. The N2adsorption properties on pellets with different micro-structure are compared. Very detailed results regarding the effects of the crystal fraction, crystal distribution are revealed.
Effect of Nanofiber Diameter on Filtration Efficiency
Authors: Liu Yan Ping , Deng Yi Bing , Jiang Zheng Xiong
Published: August 2012

Electrospinning and its application in ﬁltration area have been caught much attention because of the large surface-to-volume ratio of nanoweb , which affects the ﬁltration efﬁciency by possibly giving more particle-capture sites. In this study, PAN is electrospun to produce ultra-ﬁne nonwovens, and its characteristics as ﬁlter media are investigated.
InGaAs Nanoflowers Grown by MOCVD
Authors: Zhang Tie Min , Miao Guo Qing , Fu Jun , Ban Dong Mei , Shen Zhen Jiang , Lin Hong , Zou Xu , Peng Hong Yan
Published: August 2012

InGaAs nanoflowers have been prepared on InP substrates by MOCVD, using TMIn, TMGa and AsH3 as reactive precursors at 420 oC. Through observation by scanning electron microscopy, we find that InGaAs nanoflowers are composed with blades and rods. The flower patterns are controlled by the growth temperature. The nanoflowers of InGaAs are disappeared, when we alter the growth temperature up and down. The InGaAs nanoflowers are In0.98Ga0.02As.
Enhanced Magnetoelectricity and Large Phonon Abnormality of Feather-Like CoFe2O4-BaTiO3 Nanostructures
Authors: Deng Yu , Wu Di , Du You Wei
Published: August 2012

By cost-effective techniques of hydrothermal reaction and polymer-assisted deposition, Feather-like (CoFe2O4)0.3-(BaTiO3)0.7 (CFO-BTO) nanostructures have been synthesized. The nanostructures show an average diameter of 250 nm and lengths up to 5 μm, with CFO nanopillars embedded in BTO matrix. The three-dimensional microstructure and growth mechanism of the nanostructures have been investigated. A large magnetoelectric (ME) response at room-temperature and a strong phonon abnormality between 110 °C and 140 °C have been studied.
Enhanced Magnetic Properties and Spin-Phonon Coupling of Single-Crystalline BiFeO3 Nanorods Prepared by Hydrothermal Technique
Authors: Deng Yu , Wu Di , Du You Wei
Published: August 2012

By hydrothermal methods single-crystalline BiFeO3 (BFO) nanorods with diameters of 15-40nm and lengths of 100-400nm were synthesized. The rhombohedra phased nanorods grow along the [110] direction. The nanorods show weak ferromagnetism at room temperature and enhanced spin-glass type magnetism at low temperature. Around 100K, a strong spin-two-phonon coupling has been detected, confirming the spin-glass freezing behaviors. With emphasis on the size and morphology, the enhanced magnetism and the spin-glass freezing of the BFO nanorods have been discussed.
Synthesis of Micro-Mesoporous Titanium-Silicon Molecular Sieve by Dual Templates Method
Authors: Wang Weng Ju , Zhu Shu Guang , Wang Jie , Liu Xin Zhi
Published: August 2012

Micro-mesoporous titanium-silicon molecular sieve (MMTS) was synthesized through dual templates method. The physical characterization of MMTS was carried out by BET, FTIR, UV-Vis. The results showed that the MMTS samples synthesized by dual templates method possessed mainly micropores and some mesopores with pore size of 3.9 nm, but a portion of the titanium in the framework was removed as indicated from UV-Vis diffuse reflectance spectroscopy.
Effect of Dopants on the Microwave Magnetic Characteristics of FeCoBM-Al2O3 Soft Magnetic Thin Films
Authors: Xiong Xuan , Feng Ze Kun , Wang Xian , Chen Zhong Yan
Published: August 2012

A series of FeCoBM (M=Nb, Zr, Hf, Mo ,Ta, Ti)–Al2O3 ﬁlms were prepared on glass and polymer substrates by means of RF magnetron co-sputtering. Effect of dopants on the soft magnetic properties and microwave magnetic characteristics of FeCoBM-Al2O3 Thin Films were studied. To further tailor the magnetic characteristics of the films, the (Fe40Co40B20)94.5Hf2.5–(Al2O3)3 film was annealed at 200 to 400°C for 60 min. As a consequence, the (Fe40Co40B20)94.5Hf2.5–(Al2O3)3 film annealed at 350°C exhibit excellent properties with high saturation magnetization of 1197 kA/m, high resonant frequency of 1.76 GHz, and the real part of permeability is about 600, which is maintained up to 1.5GHz. These results show that the presented films possesses potential in designing micro-magnetic devices for Monolithic Microwave Integrated Circuit (MMIC) and surface mount technology (SMT)industry.
Application of Composite Materials to Large Marine Hatch Cover
Authors: Li Jun , Wu Nan Huo , Tang You Hong , Zhao Cheng Bi , Li De Yu , Lin Wei , Liang Fu Lin
Published: August 2012

A large number of laminates have been used in marine structures, such as small boat hulls, superstructures and propellers, etc. In this study, the using of composites in large scale marine hatch cover and comparison of strength, weight and cost between the conventional marine hatch cover and the composite hatch cover are investigated. The results show that the composite hatch cover is feasible and has great potential for future use because of its higher strength, lighter weight, super-corrosion resistance and economic.
Preparation and Characterization of Zn1-XMnxO Thin Films on SiO2 Substrates
Authors: Zhao Yue Zhi , Xiong Fei , Gao Guo Mian , Ding Shi Jing
Published: August 2012

Mn-doped ZnO thin films were prepared on SiO2substrates by using a radio-frequency(rf) magnetron sputtering in order to investigate structure and optical proprieties of the films. X-ray diffraction (XRD), Atomic force microscope (AFM) and UV-VIS spectrophotometry were employed to characterize the Mn-doped ZnO films. The results showed that the shape of the XRD spectrum was remarkably similar to that of the un-doped ZnO film; the film had mainly (002) peak, and indicate that the structure of the films was not disturbed by Mn-doped. The film had rather flat surfaces with the peak-to-tail roughness of about 25nm. Mn-doping changed the band gap of the films, which increased with the increase of the Mn content.
Mixed Conducting Ceramic Capillary Membranes for Catalytic Membrane Reactors: Performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ Capillaries
Authors: Snijkers Frans , Buysse Cédric , Middelkoop Vesna , Buekenhoudt Anita , Kovalevsky Andrei
Published: August 2012

Oxygen-permeable perovskite ceramics with mixed ionic-electronic conducting properties can play an important role in the high temperature separation of oxygen from air. Such membranes are envisaged for application in catalytic membranes reactors and in oxy-fuel and pre-combustion technologies for fossil fuel power plants enabling CO2 capture. Since large-scale gas separation applications demand high membrane surface/volume ratios, membranes with capillary or hollow fiber geometry have a distinct advantage over tubular and flat sheet membranes. The fabrication and performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) capillary membranes is presented. The capillaries were made by a spinning technique based on phase inversion using a sulfur or non-sulfur containing polymer binder. Attention is given to the polymer solution and ceramic spinning suspension in order to avoid the formation of macrovoids and achieve gastight membranes. The comparison of the performance of sulfur-free and sulfur-containing BSCF capillaries with similar dimensions revealed a profound impact of the sulfur contamination on both the oxygen flux and the activation energy of the overall oxygen transport mechanism. In addition the effect of activation layers on oxygen permeation is studied.
Study on Thermophysical Properties of Partially Oxidized Polymer Derived SiC Composites
Authors: Han Xiao Yi , Cheng Hai Feng , Xing Xin , Wang Jun
Published: August 2012

SiC ceramics were synthesized by polymer derived method and microwave sintering processes. The as-produced SiC composites were developed by oxidizing the amorphous Si-C raw materials derived from a polymer precursor polycarbosilane. The products analyzed by X-ray diffraction (XRD), Fourier transmittance infrared spectroscopy (FTIR), and electronic microscopye consist of excess free carbon, β-SiC and SiO2 produced by the partial oxidation of amorphous Si-C on the surface of the starting particles. The thermophysical properties of the partially oxidized SiC composites were investigated by measuring the thermal diffusivity, the specific heat and thermal conductivity. The amount of SiO2 increased as the sintering temperature is increased, resulting in a reduction of thermal diffusivity and an increase of density due to improved liquid phase sintering of SiC particles. The thermal conductivity of samples decreased, instead of increased, as the sintering temperature was increased from 1100 °C to 1200 °C. The sample dwelled at 1200 °C, in this study, has highest density and a relatively low thermal conductivity, slightly over 0.7 W/(m·K) at room temperature.
The Synthesis and Electrochemical Performance of LiV3O8 Cathode with Lanthanum-Doped
Authors: Hu Fang , Sun Mo Ran , Wu Yu Sheng , Zhang Chun Hua
Published: August 2012

Li1-xLaxV3O8 cathode materials has been synthesized by pechini sol-gel method. The electrochemical performances of Li1-xLaxV3O8(x=0-0.05) have been studied by X-ray diffraction (XRD), galvanostatic charge-discharge, and cyclic voltammetric (CV). The results showed that the optimal content of the La3+ doping in LiV3O8 was x=0.01, and the first discharge capacity of Li0.99La0.01V3O8 sample in the voltage range of 2.0-4.0V was 230mAhg-1, which was much higher than that of LiV3O8 (200mAhg-1). The Li0.99La0.01V3O8 cathode also showed higher discharge voltage plateau than LiV3O8 cathode from the CV curves.
Novel Anion Exchange Membranes from Poly(aryl ether)s with Quaternary Guanidinium Groups
Authors: Cui Yu Fang , Du Jin Yan , Shang Yu Ming , Wang Yao Wu , Wang Jin Hai , Lv Ya Fei , Wang Shu Bo
Published: August 2012

A series of fluorinated poly(aryl ether oxadiazole)s (FPEO) were synthesized and brominated with N-bromosuccinmide (NBS) which were then functionalized with quaternary guanidinium to get fluorinated anion exchange membranes （AEM）with pendant quaternary guanidinium Groups. The structure of resulting polymers was characterized by FTIR spectroscopy. The properties of the obtained membranes were investigated in terms of ion exchange capacity (IEC), swelling ratio, area resistance and vanadium permeability. The results showed that the novel anion exchange membranes possess much higher selectivity in VRB system. The permeation rate of vanadium ions of GFPEO is 0.21×10-7 cm2min-1 which is much lower compared with that of Nafion.
Synthesis of the Cu/Flokite Catalysts and their Performances for Catalytic Wet Peroxide Oxidation of Phenol
Authors: Xu Jun Qiang , Guo Fang , Li Jun , Ran Xiu Zhi , Tang Yan
Published: August 2012

The supported Cu/Flokite catalysts were prepared by conventional incipient wetness impregnation. The catalysis oxidation degradation of phenol was carried out in heterogeneous catalyst and H2O2 process. The results indicated that the reaction system with catalyst and hydrogen peroxide was more benefit to degradation of phenol. When the phenol initial concentration was 100 mg/L, the phenol removal over the 2.5%Cu -2.5% Fe/Flokite catalyst could reach 96%. The peroxide catalytic oxidation process over the enhanced heterogeneous catalyst would be a novel technique for the treatment of phenol wastewater.
Ultrafiltration Treatment and Physical Properties of Ammonia Sulfite Pulping Liquor of Wheat Straw
Authors: Wang Zhe , Xue Jing Wen , Zhang Ji Shi , Liu Wen Xia
Published: August 2012

Ammonia sulfite pulping liquor of wheat straw was treated by ultrafiltration. Experimental results indicated that the membrane with a cut-off of 10kDa was suitable for concentrating wheat straw liquor and had good anti-fouling property against pulping liquor. Permeability of ash turn higher with the increasing of volume reduction at the operating condition of 200 kPa and 25°C, and retentate was concentrated when volume reduced. Influences of ultrafiltration on physical properties of ammonia sulfite pulping liquor and its retentate after ultrafiltration were studied. Results showed that retentate had better performances as surfactant, concrete additive and dispersant. Surface tension of 1% lignin solution of retentate was 54.7 mN/m, which was lower than that of the untreated original lignosulfonate by 2.2 mN/m. Dispersing effect of retentate on cement was also investigated, it was found that flowability of neat cement paste improved from 70mm to 102mm.
Asymmetric Heat Transfer of Deformation on Frictional Surface of Mechanical Seals
Authors: Yu Long , Yu Shu Rong
Published: August 2012

Given the heat transfer and force characteristics, seal ring was simplified to be equivalent to a circle. The heat transfer coefficients and temperature distribution on both rotating and stationary rings were calculated. A simplified thermal distribution model was developed for rotating and stationary rings according to the law of energy conservation and a verification method was proposed. Based on this, the deformation relationship of friction surfaces on which both heat and pressure were applied. Comparison was made between average and asymmetric thermal distributions and verified by FEM. The results showed that the deformation of stationary ring exceeds the allowed deformation amount in heat average distribution. The result of deformation is in agreement with testing results.
Influence of Cr Valence State on Dielectric-Temperature Stability of Barium Titanate Ceramics
Authors: Lu Da Yong , Zhang Li , Han Dan Dan , Wang Yan Dong , Yang Xue , Sun Xiu Yun
Published: August 2012

For Barium Titanate Ceramics doped with the trivalent and hexavalent chromium oxides, the influence of Cr valence state on dielectric-temperature stability was investigated with Atomic force microscopy, X-ray diffraction, Raman spectroscopy, and dielectric measurements. The application of the trivalent Cr2O3 dopant can give rise to a temperature-stable X7R specification and a lower dielectric loss (< 0.02) when the sample was prepared at 1240 °C, but the dielectric permittivity is lower (~600); Cr ions exist predominantly as Cr4+ and slightly as Cr3+. Increasing sintering temperature will destroy the core-shell structure of the samples. The application of the hexavalent CrO3 dopant can not produce a temperature-stable X7R ceramic; Cr ions exist as Cr4+ and Cr5+. Cr5+ can not enter the perovskite lattice owing to the valence mismatching.
Study on the Characteristics of ThioPP Thin Films for Low-κ Applications
Authors: Cho Sang Jin , Kim Hoon Bea , Jung Dong Geun , Boo Jin Hyo
Published: August 2012

The thiophene plasma polymer was deposited on silicon(100) substrates by PECVD (Plasma Enhanced Chemical Vapor Deposition) with homemade stainless steel vacuum chamber. Thiophene was utilized as organic precursor with hydrogen gas as bubbling gas. Argon gas was used as a carrier gas. To analyze the electrical properties of the plasma polymerized thin films, the plasma-polymer thin films were grown under various RF power condition. The as-grown plasma-polymer thin films were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), measuring the capacitance, impedance analyzer, ellipsometry, Fourier Transform Infrared spectroscopy (FT-IR), and water contact angle measurement. AFM and SEM images showed smooth surfaces of thin films with increasing RF power. An impedance analyzer was utilized for the measurements of I-V curves (for leakage current density) and capacitance (for dielectric constant). Refractive indices were increased by increasing RF power. The IR spectra showed that the plasma polymer thin films have totally different chemical functionalities from liquid thiophene precursor, as well as the changing chemical functionalities of the thin films caused by various RF powers. The best dielectric constant is 2.52 in this study.
An Analysis on the Effect of Fiber Entanglement in the Hydroentangled Nonwovens and the Initial Research of Influencing Factor
Authors: Zhu Jing Jing , Wang Hong , Wu Hai Bo , Jin Xiang Yu
Published: August 2012

The hydroentangled nonwovens have be widely used today. But the basic research of the hydroentangled nonwoven technology is relatively weak. It is not very clear so far that how the fibers are entangled with each other in the spunlaced nonwoven fabrics. In this paper, the pulling-out behavior of single fiber from hydroentangled nonwoven was first studied and analyzed the stress situation of the entanglement points in order to investigate the entanglement of the fibers in the hydroentangled nonwovens. It is found that the bigger of the pulling-out force, the more fibers are broken and the resultant hydroentangled nonwovens show better tensile property. So the pulling-out force can be used to weight the fiber entanglement effect in the hydroentangled nonwovens. Moreover, in this paper we also discover the fiber performance which can influence the fiber entanglement effect during the hydroentangled process by the cohesive of fibers, and the theory instruction will be provided to develop new fibers in the spunlaced process.
Influence of Zn Content on the Microstructure and Properties of As-Annealed Al-Mn-Si Alloys
Authors: Kang Shao Hai , Ding Dong Yan , Gao Yong Jin
Published: August 2012

The effect of Zn addition on the microstructure, tensile properties and electrochemical properties of as-annealed Al-Mn-Si alloy was investigated through TEM observations, anodization metallography, tensile tests and Tafel polarization analysis. High density precipitates were found in the Zn-containing alloys and the alloy with 1.5 % Zn had the most uniform precipitation. The Zn element could restrain recrystallization of the alloy. Tensile test results indicated that Zn has a great effect on tensile strength of Al-Mn-Si alloy. The alloy with 1.8 % Zn addition had the highest ultimate tensile strength. The electrochemical testing results indicated that Zn element had great impact on the corrosion potential of the as-annealed alloys tested in 0.5% NaCl solutions. Alloying with Zn element could make the corrosion potential shift to negative direction but increase the resistance to pitting corrosion
Influence of Aging Temperature on Microstructure and Creep Properties of Hot Continuous Rolled Ti-6Al-4V Alloy
Authors: Xiao Li , Tian Su Gui , Bao Xian Yu
Published: August 2012

Hot continuous rolling technique is a new processing method for preparing Titanium alloy, which may decrease the production cost and realize continuous industrial manufacture. Ti-6Al-4V alloy was prepared by hot continuous rolling (HCR) and solution and aging treated at different temperature. Creep curves of the alloys were measured, microstructure evolution feature of the alloys during creep was observed by SEM and TEM. The influence of aging temperature on the microstructure and creep property of the alloy is briefly discussed. Results show that, the microstructure of HCR alloy after solution treatment at temperature higher than β phase transus point consists of the fully "basket weave" structure. The alloy aged at 750 °C has higher strain rate and shorter creep lifetime, strain rate of the alloy during steady-state creep is measured to be 0.69 × 10-7/s, creep lifetime is measured to be 180h, and strain rate of the alloy aged at 480 °C is measured to be 0.33 × 10-7/s. The alloy aged at lower temperature has longer creep lifetime than the alloy aged at high temperature.
Epoxy Resin Modified with PEDOT/PSS and Corrosion Protection of Steel
Authors: Hou Jian , Zhu Guang , Xu Jing Kun , Wang Jun Tao , Huang Yao
Published: August 2012

An epoxy paint containing PEDOT/PSS was described herein. The corrosion behavior of steel samples coated with the paint was investigated in seawater. For this purpose, electrochemical impedance spectroscopy was utilized and surface morphology of coatings after corrosion was observed using scanning electron microscope. It was found that the addition of small PEDOT/PSS to the epoxy resin increased its corrosion protection efficiency. Meanwhile, the possible mechanism was discussed.
A Polycrystal Plasticity Model and its Application in Deep Drawing of a FCC Metal
Authors: Li Hong Wei , Yang He
Published: August 2012

This study developed a new polycrystal plasticity model by deducing a set of linear controlling equations with respect to the controlling equation of rate dependent crystal plasticity (RDCP). It was proved numerically efficient and stable by means of the comparison with experiment and an implicit model. The model was then applied to describe earing in deep drawing process. Remarkable effects of rate sensitivity coefficient of the material, drawing speed and dies clearance on earing were found.
Preparation and Oxygen Permeability of ReBaCo2O5+δ (Re = Pr, Nd, Y) Ceramic Membranes
Authors: Kim Jong Pyo , Pyo Dae Woong , Magnone Edoardo , Park Jung Hoon
Published: August 2012

ReBaCo2O5+δ (Re=Pr, Nd, Y) oxides were synthesized by solid state reaction method. The oxygen permeation flux of ReBaCo2O5+δ (Re=Pr, Nd, Y) membranes increased with temperature and oxygen partial pressure and ranked as follow: PrBaCo2O5+δ > NdBaCo2O5+δ > YBaCo2O5+δ. The oxygen permeation response of PrBaCo2O5+δ membrane was fairly stable and no detectable degradation is observed at high temperature under carbon dioxide conditions (CO2 = 500 ppm).
Enhanced Ferromagnetism in Zn0.99Fe0.01O Modified by High Pressure
Authors: Wang Yong Qiang , Cheng Xue Rui , Su Lei , Hao Jun Hong
Published: August 2012

Polycrystalline bulk sample Zn0.99Fe0.01O was fabricated by a solid-state reaction method and modified by high-pressure treatment technique at a pressure of 5GPa. The structure, morphology and magnetic properties of these samples were investigated in order to clarify the effect of pressure on magnetism of Zn-Fe-O system. It is found that the particle size of the modified samples becomes larger as well as the physical contact between neighboring particles becomes better. All samples show obvious ferromagnetic behaviors at room temperature, and the magnetization of modified samples greatly increases. It is believed that the larger particle size and the closer contact between neighbouring particles resulted from high-pressure treatment cause stronger ferromagnetic exchange interaction in Zn-Fe-O system.
Effects of Lubrication on the Powder Metallurgy Processing of Titanium
Authors: Lou Jia , Gabbitas Brian , Zhang De Liang
Published: August 2012

The role of lubrication on the consolidation behaviour of titanium powder, density increase and change in microstructure on subsequent sintering was investigated. HDH titanium powder mixed with 0-2wt% stearic acid or magnesium stearate was cold compacted. It was found that 0.3-0.6wt% of internal lubricant significantly improves the compressibility. However, more than 0.6wt% of lubricant aids the densification in the low-pressure region but limits the maximum density at high pressure. Moreover, 0.3-0.6wt% of lubricant offers a more uniform density distribution to the powder compact, while greater than 0.6wt% of lubricant leads to a segregation of lubricant in the surface region. The shape retention, ejection behaviour, de-lubrication behaviour and sintered properties were also studied in this work.
Effect of Contaminants on Sintering of Ti and Ti-6Al-4V Alloy Powders in an Argon-Back-Filled Graphite Furnace
Authors: Yu Chang Zhou , Cao Peng , Jones Mark Ian
Published: August 2012

This work aims to study sintering of elemental titanium and pre-alloyed Ti-6Al-4V powders in a graphite furnace which is operated with back-filled argon. The specific task is to investigate the effect of carbon, oxygen and nitrogen contamination in the furnace atmosphere during sintering. X-ray diffraction (XRD) reveals that the main phase on the surface of the sintered samples was a titanium oxycarbonitride – Ti(CNO). The surface of all samples was porous due to the reaction between titanium and contaminants. A close-up surface morphological observation with environmental scanning electron microscopy (ESEM) shows the presence of spherical particles in the sintered Ti specimens, but not observed in the Ti-6Al-4V alloy specimens. Energy dispersive spectrometry (EDS) results indicate that these spheres mainly contain carbon and titanium. It is postulated that residual chlorine (Cl), a common impurity for sponge Ti powder but not for pre-alloyed Ti-6Al-4V powder, may play an important role in the formation of these spheres. Microhardness is dependent on the contaminant content on the sample surface. The implication of using graphite furnaces for sintering is discussed.
Pathways to Optimize Performance/Cost Ratio of Powder Metallurgy Titanium – A Perspective
Authors: Fang Z. Zak , Sun Pei
Published: August 2012

Powder Metallurgy (PM) Titanium has great potentials as low-cost alternative for Ti manufacturing, but the use of conventional PM processes for producing Ti products is also limited due to reasons related to either that the properties are not as satisfactory as that of equivalent wrought materials, or the cost advantage is not as significant as it was expected. Therefore, the main challenge of developing PM Ti is to increase performance to cost ratio. Reduction of costs and improvement of final products must involve every step of the entire process. This article attempts to assemble a set of processes by selecting individual unit processes that when combined synergistically could offer the optimum performance to cost ratio. This set of processes include using low cost powders, using automatable near-net-shape compaction techniques, and using sintering using sintering technologies that can produce parts with very fine grain sizes, thus satisfactory mechanical properties, in as-sintered state.
Design Strategy of Binder Systems for Ti Injection Moulding
Authors: Wen Guian , Cao Peng
Published: August 2012

It has been two decades since the first report on titanium metal injection moulding (Ti-MIM) was published in 1988. The top secret for MIM practitioners and feedstock suppliers is the binder, which largely determines the success of Ti-MIM processes. As a consequence of its high affinity to oxygen and carbon, Ti injection moulding requires a more stringent control of contamination and therefore a different design strategy must be used for Ti-MIM binders, as compared to that for other metals injection moulding. This paper first discusses key requirements for Ti-MIM binder and then provides some case studies to discuss several major binders systems, followed by an outlook of the future binder development.
Debinding Kinetics of a Water Soluble Binder System for Titanium Alloys Metal Injection Moulding
Authors: Chen Gang , Wen Guian , Edmonds Neil , Cao Peng , Li Yi Min
Published: August 2012

A water soluble binder system is used to prepare Ti-6Al-4V and NiTi pre-alloyed powder feedstock. The binder dissolution and transport kinetics through the porous powder skeleton are studied for various powder morphologies and powder loadings from 60 to 69.5 vol.%. The binder removal behaviours are evaluated with different debinding time intervals. The focus of this work is to investigate the influences of shaping pressure, specimen thickness and water bath temperature on the binder extraction behaviour.
Biomedical Ti-24Nb-4Zr-7.9Sn Alloy Fabricated by Conventional Powder Metallurgy and Spark Plasma Sintering
Authors: Guo Shi Bo , Cai Chun Bo , Zhang Yong Qiang , Xiao Yong , Qu Xuan Hui
Published: August 2012

Ti-24Nb-4Zr-7.9Sn alloy was prepared by Powder Metallurgy (PM) and Spark Plasma Sintering (SPS) using titanium hydride powder, niobium powder, zirconium powder and tin powder as raw materials. The effect of sintering process on microstructure and mechanical properties was investigated by mechanical measurement and SEM. The results showed that the best sintering process by PM was at 12500C for 2 h. The relative density, tensile strength and elongation of the alloy reached 97.2%, 705MPa and 6.2%, respectively. The microstructure was a typical Widmannstatten microstructure, which possessed β-matrix and α-precipitation. The best process by SPS was at 12500C. The relative density, tensile strength and elongation of the alloy sintered by SPS reached 99.4%, 788.5MPa and 6.4%, respectively. The grain size was about 100µm and the microstructure was uniform. The fracture morphology of the alloy was ductile rupture. Compared to PM, Ti-24Nb-4Zr-7.9Sn alloy fabricated by SPS exhibited better comprehensive properties and more uniform microstructure.