bluuebunny/crossref_metadata_2025 huggingface dataset:
The Adsorption Performance of Furfural Residue for Plumbum Ion
Authors: Ren Guang Jun , Wan Xiao Long
Published: November 2013

The adsorption performance of Plumbum ion from aqueous solution by furfural residue was studied. The results show that the adsorption of Plunbum on furfural residue reached equilibration by 60 minutes. The removal efficiency of Plumbum ion in aqueous solution on furfural residue of Plumbum ion achieved the 92.89% in 50mL 200mg.L-1 Plumbum ion aqueous solution with adding 4g/L furfural residue. The temperature had an effect on the removing of the Plumbum ion on furfural residue, and the adsorption of furfural residue to Plumbum ion was decalescence reaction. The relationship between adsorbing capacity (qe) and equilibrium mass concentration (ρe) is in accordance with the isothermal adsorption equations of Freundlich and Langmuir.
Experimental Study of Flotation on High Intensity Magnetic Concentrates of Ilmenite
Authors: Bai Li Mei , Zhang Shao Min , Zhang Da Yong , Dai Shu Juan , Li Meng
Published: November 2013

In order to improve the separating index of ilmenite to separate the concentrate by high intensity magnetic separation, the Heishan iron ore in Chengde did some work. Separate the sulfide ore out by flotation under the conditions of concentration by weight in feed 32%, consumption of xanthate 200g/t and 2# oil 40g/t. Use sulfate to adjust the pH of the low sulphur product of flotation, the mixture of EM351-2 and EM351-3 as foaming agent, after one roughinging and four fold concentrating, got the final titanium concentrate, the grade of which is 47.23%, and the recovery is 58.29%. During the procedure of roughing, the consumption of the reagent as follows: sulfate 2kg/t, EM351-3 1kg/t, EM351-2 900g/t. The consumption of sulfate during fourfold concentrating is 1kg/t. The index is more stable when the concentration in feed is 18%~26% during flotation. The index is stable during the continuous 26 work time for the process under this reagent system. The screen analysis of the flotation concentrate indicates that this reagent system has a better effect on the flotation of +0.074mm particles, and a bad effect on the flotation of-0.045mm particles.
Flotation Tests of Zinc Oxide Ore with Iron
Authors: Yang Jin Lin , Zhang Hong Mei , Mo Wei , Ma Shao Jian , Su Xiu Juan
Published: November 2013

Flotation tests for recovering zinc and iron from gossan ores was carried out in this paper. Flotation is the most commonly used method for beneficiation and pretreatment of oxidized zinc minerals. The effects of grinding fineness, amount of Na2CO3, amount of Na2SiO3, amount of Na2S and amount of octadecylamine were investigated, respectively. The results show that the grade of zinc and iron increase slightly, and the best result is that the grade of zinc and iron are 13.12% and 41.15%, the recovery of zinc and iron are 76.83% and 77.95%. The results simply indicated that flotation could not effectively recover zinc and iron from gossan ores studied in this paper.
Flotation Behavior of Jinchuan High Grade Copper-Nickel Sulphide with the Action of Different Regulators
Authors: Shen Shuai Ping , Yuan Zhi Tao , Li Li Xia , Zhu Shuo
Published: November 2013

The useful minerals of Jinchuan high-grade copper and nickel suphfide ores were mainly nickel and copper, whose grade were respectively 1.42% and 1.01%. The content of MgO and SiO2, main gangue components, reached 57.89%. The key to improve the separation indexes of flotation concentrate was to inhibit the gangue minerals effectively, therefore, the effects of different kinds of regulators on Jinchuan high grade copper-nickel ores by flotation were studied. Considering the grade and recovery of concentrate comprehensively, the optimal regulator of mineral flotation was determined to be the combination of sodium hexametaphosphate and citric acid, and the dosage were 300g/t and 500g/t, respectively. After analyzing the mechanism of the two regulators, the combined reagents could reduce the isoelectric point of gangue minerals, decreasing the adsorption between gangue minerals and valuable minerals. In addition, the reagents were able to eliminate the activation of useless ions such as Ca2+ and Ni2+ on the gangue minerals and improve the ion composition of pulp, increasing the difference of floatability between gangue and useful minerals.
Mechanical Grinding Improved Quality of Potassium-Feldspar Rocks
Authors: Lv Le Fu , Gai Guo Sheng , Liu Chun Sheng , Yang Yu Fen , He Zhen Quan , Li Wan Cai , Zhang Xian Mei
Published: November 2013

Potassium-feldspar rocks were ground for 10, 40, 120 and 180 minutes respectively using a porcelain ball mill. The kinetics of potassium release from activated rocks and their effect on yield and nutrient uptake by grain amaranth were evaluated. Results showed that high intensive grinding could improve physicochemical properties and bioavailability of potassium-feldspar rocks. With increasing grinding time, the particle diameters were decreased, the specific surface areas were increased, and the diffraction peaks were decreased remarkably. Maximum release of acid-soluble K was obtained in all rocks during the initial stages of leaching (0-10days), but their differences narrowed down at latter stages (10-60days). The cumulative release of K from the rock treated for 180 minutes was the highest amount (5331.51 K mg/kg rocks) and was 3.75, 1.29 and 19.8% higher than the rocks treated for 10, 40 and 120 minutes, respectively. Data from pot experiment revealed that activated rocks with higher bioavailability promoted the growth and K accumulation of gain amaranth. This study indicated that mechanical activation could be an alternate technology for the efficient of using potassium-feldspar rocks for crop production.
Preparation of Iron Oxide Red from Red Mud
Authors: Ma Zheng Xian , Liu Qiao Ling , Wang Lan Qin , Pang Lu Feng
Published: November 2013

With using the red mud of Bayer process and industrial hydrochloric acid as main initial materials, iron oxide red was prepared by chemical precipitation technique. The character of the sample were characterized and analyzed by means of XRD, SEM, particle size analyzer, and chemical analysis methods, respectively. The optimal experimental condition of extraction of iron from red mud was obtained, and the key quality indicators of sample was conformed the requirements of iron oxide red by a variety of test and characterization.
Effect of Aluminum Dross on Properties of the Lightweight Mullite Aggregate
Authors: Sun Guang Si , Gu Hua Zhi , Fang Yi Neng , Feng Yun Sheng
Published: November 2013

The lightweight of refractory is propitious for energy-saving and emission-reduction of the high temperature refractories industry and sustainable development of the refractories resource. This paper researches on properties of the lightweight mullite aggregate which is prepared by two kinds of bauxites and aluminum dross and fired at 1400°C,1450°C,1500°C,1600°C for 1h. The result shows that, (1)The minimum density of grade Ⅰ bauxite is 2.11g/cm3 which is prepared by adding 50wt% aluminum dross and fired at 1600°C; (2)The minimum density of grade Ⅲ bauxite is 1.54g/cm3 which is prepared by adding 50wt% aluminum dross and fired at 1450°C.
Grain Refinement Mechanism of MgAlON Composites Prepared by Spark Plasma Sintering
Authors: Yang Dao Yuan , Feng Xiao Cong , Qu Yuan Chao , Yuan Fei , Zhang Cun Bao
Published: November 2013

The paper developed a computing model to analyze the grain refinement mechanism of MgAlON composites sintered by spark plasma sintering (SPS). Using alumina, magnesia and aluminum as raw materials MgAlON composites were prepared by SPS. Based on the current assignment principle, the heating rate at different positions in Al grains was analyzed, and the particle radius during the sintering process could be calculated. The results suggested that necks could be formed between MgAlON particles with electric current heating rapidly to reduce particle radius, the shorter vertical distance from the interface was, the larger heating rate and growing rate of the neck had; the necks between particles be formed dynamically in the sintering process, so the big particle radius would be getting smaller and smaller continually so that we could get a large amount of micro particles distributed uniformly in the sintered MgAlON composites, and the resulted grain refinement was more obvious.
Electrical Characterization and Microstructures of Bi4-x HoxTi3O12 Ceramics
Authors: Mei X.A. , Chen Min , Liu J. , Liu R.F.
Published: November 2013

The electrical properties of Ho2O3-bismuth titanate (Bi4-xHoxTi3O12) prepared by a conventional ceramic technique have been investigated. At applied d.c. field below 200V/mm, the current-voltage curve of Ho-doped sample exhibits a simple ohmic behavior. The impedance spectrum of Ho-doped sample indicates that consist of semiconducting grain and moderately insulating grain boundary regions. XRD, SEM and EPMA analyses reveal crystalline phase characterized by a Bi-layered perovskite structure of Bi4Ti3O12 and the distribution of every element is uniform. Ho-doped sample exhibit randomly oriented and plate-like morphology.
Cover Confinement and Ballistic Performance of TiC-TiB2 Ceramic Armor under the Impact of Long-Rod KE Penetrator of 1400 m·s-1
Authors: Lu Xiao Bo , Liu Hong Bo , Lu Hai Xing
Published: November 2013

By conducting DOP test to evaluate the ballistic performance of confined TiC-TiB2ceramic targets against long-rod tungsten alloy penetrators under the impact of 1400 m · s-1, the coorelations of the steel cover confining the ceramic tile and ballistic performance of TiC-TiB2ceramic targets were discussed. The results of ballistic testing showed that the steel covers in thickness of 1.5 mm and 3.5 mm failed to support laterally-confined ceramics due to their insufficient stiffness, resulting in poor ballistic performance of the ceramic targets with the mass efficiency smaller than 2.0. The cover in thickness larger than 10 mm had enough stiffness to ensure the mass efficiency of the ceramic target higher than 2.5. It is considered that with minimal front-surface confinement, the ejecta plume of the pulverized ceramic becomes less divergent, and this focusing of the ejected materials has the effect of further eroding the penetrator, thereby increasing the ballistic performance of the ceramic.
Pyrolysis Kinetic Behaviors of ZrB2 Ceramic Organic Precursor
Authors: Chen Ming Wei , Qiu Hai Peng , Jiao Jian , Zhang Wei Gang , Li Xu Qian , Wang Yu , Gao Shu Ya , Wang Ruo Gu
Published: November 2013

The pyrolysis dynamic process of ZrB2 organic precursor,soluble in benzene homologues with polycarbosilane, was characterized by means of on-line TG-DSC-FTIR-MS coupling technique. The conversion mechanism of ZrB2 ceramic was investigated based on EDS, SEM and XRD. The results show that methylamine, methane, acetone and propene were given off before heat treatment at 1000°C, and the pyrolysis product of ZrB2 precursor existed in the form of ZrO2, B2O3 and amorphous carbon. ZrB2 crystals are obtained completely by the carbothermal reduction process with the release of carbon dioxide at 1500°C.
Key words:ZrB2 organic precursor, pyrolysis kinetic behavior, carbothermal reduction process.
Fabrication and Properties of 3D-Cf/Mullite Composites with SiC Interfacial Coatings
Authors: Dai Ke Wei , Zhang Chen Chen , Ma Qing Song , Liu Hai Tao
Published: November 2013

Three-dimensional carbon fiber reinforced mullite composites (3D-Cf/mullite) were fabricated by sol-gel method with diphasic mullite sol as raw materials. SiC interfacial coatings were deposited by polycarbosilane infiltration and pyrolysis before sol-gel process. The as-fabricated composites showed 285.7MPa in flexural strength, relatively close to 277.6MPa of those without coatings. After treated at 1300°C and 1500°C in Ar atmosphere for 1h, the retention rates of flexural strength were 80.0% and 69.9%, respectively, which showed a great improvement compared to the composites without coatings. This was attributed to the prevention of carbothermal reduction between carbon fiber and matrix by SiC coatings.
Numerical Simulation of Pre-Crack Propagation in ZrB2-SiC-AlN Ceramics Subjected to Thermal Shock
Authors: Wan Xiao Yang , Liang Jun , Fang Guo Dong , Wang Ling Ling
Published: November 2013

The present work examines the pre-indented crack propagation in ZrB2-SiC-AlN ceramics subjected to thermal shock under different temperature differences. A cohesive force model is applied according to the shape and characteristics of the crack in the indentation - quenching experiments. A dimensionless parameter is introduced to characterize the effect of depth on thermal stress which considers the cracks propagate along both the surface and the depth direction. The modified numerical results are 11.3%, 16.6%, 20.8% 27.1% and 64.6% at the quenching temperature differences of 240°C, 280°C, 320°C and 360°C, respectively, which are in good agreement with the experimental results.
Microstructure of Al2O3+Cordierite+AlN Composite Ceramics
Authors: Ma Zhi Xin , Han Yan Ling , Wang Nan , Liu Wei Nan , Liu Yu Wei
Published: November 2013

Aiming at the preparation problems of Al2O3+cordierite+AlN composite ceramic, the experiment emphatically investigates two influencing factors both the addition of cordierite and Al2O3 and sintering process parameter. The Al2O3+cordierite+AlNcomposite ceramic has been obtained through such technique procedure as mixing materials, ball-milling, forming by dry pressing and pressutrless sintering in nitrogen at temperature between 1350°C~1400°C. The chemical compositions of ceramic are examined by XRD diffraction. The microstructure and composition of the fracture of the materials are observed by SEM and EDS. The results show that owing to the addition of cordierite the composite ceramic has been sintered at 1375°C;the composite ceramic are more dense sintering at higher temperature; more Al5O6N can be obtained by improving the content of AlN, thus improving the thermal conductivity.
Influence of different Thickness of Zirconia Core on the Flexural Strength in Article Saliva
Authors: Yu Guo Xi , Wang Le , Fan Zhang
Published: November 2013

To Study the Effect of Different Core Thickness on the Flexural Strength of Zirconia and Feldspathic Ceramics. Bilayered Zirconia-Feldspathic Samples of Three Commercial Brands were Made in Three Different Thickness(n=10): 0.5 Mm, 0.8 Mm and 1.0 Mm Respectively. on Zirconia Core Specimens of each Thickness, Feldspathic Dentin Porcelain was Added to Reach a Total Crown Thickness of 2 Mm. Samples were Stored in Artificial Saliva with Neutral Ph for 10 Days at 37°C. Flexural Strength was Conducted with 3-Point Bending Test. Data were Analyzed by One-way ANOVA, and Multiple Comparisons were Performed Using Student-Newman-Keuls Test(α=0.05). the Measurement of 1.0 Mm Group was Higher than the other Groups, and 0.5 Mm Group was the Lowest(P＜0.05), Regardless of any Commercial Brand. Commercial Dental Zirconia Blocks had Varied Flexural Strength, Zirkonzahn Expressed Highest Value in any Thickness Group Compared with the other Materials. Moreover, the Fracture Mode of Zirconia Bilayered Composites was Different in this Study, 0.5 Mm and 0.8 Mm Groups Exhibited Higher Number of Fragments and Appeared to Delamination Compared with 1.0 Mm Group. so we Infer that the Thickness of Core can have an Effect on the Flexural Strength of Bilayered Zirconia-Feldspathic Crown, as well as Different Kinds of Materials.
Effect of Different Surface Treatments on Push-Out Bond Strength of Zirconia Oxide Posts
Authors: Yu Guo Xi , Zhang Song , Fan Zhang
Published: November 2013

To Investigate the Effect of Different Surface Treatments on Push-out Bond Strength of Zirconia Oxide Posts in Root Canals. Sixty Single Rooted Extracted Teeth were Collected and Divided into Two Groups. Custom Milled Zirconium Oxide Posts (Cercon, Degudent, Germany; Cosmopost, Ivoclar, Liechtenstein) were Fabricated. Post Specimens of each Group were Subjected to Different Surface Treatments (n=10): no Treatment (control), Sandblasting then Silane Coating and Silane Application (SB+SC+SI), Sandblasting and Silane Application (SB+SI). all Specimens were Bonded with Relyx Unicem and Horizontally Sectioned into Three Sections and Subjected to a Push-out Test. Data were Analyzed Using Two-way ANOVA. Cercon Recorded Significant Higher Bond Strength than Cosmopost (P＞0.05). Surface Treatments Recorded Higher Values than Control Group, and SB+SC+SI Presented Higher Bond Strength than SB+SI (P＞0.05). there was no Significant Difference among Different Root Regions (P＞0.05). Therefore Cercon May be more Suitable to be Used as Post Materials than Cosmopost. Surface Treatments have Significant Effect on Push-out Bond Strength of Zirconia Oxide Post and SB+SC+SI Group Presents Better Bond Strength than SB+SI Group.
Preparation of La2(CexZr1-x)2O7 Nano-Porous Powders via Citric Acid Derived Sol-Gel Processing
Authors: Zheng Lu , Guo Jian Qiu , Liu Liang Bin , Tang Yin Xin , Guo Yu Zhong
Published: November 2013

La2(CexZr1-x)2O7 powders were synthesized by the Pechini routine with citric acid as a chelating agent. TG-DTA, XRD and SEM were used to characterize as-prepared powders. Experimental results show that the crystalline structures of La2(CexZr1-x)2O7 transform to cubic fluorite phase with Ce substitution for Zr from x=0.1 to 1.0, no longer keeps the cubic pyrochlorite structure of La2Zr2O7. La2(CexZr1-x)2O7 powders present nanoporous low-density microstructurally, and successively lump-like, fluff-like and cotton-like morphologically with the increase of citric acid addition, this typical nanoporous microstructure results from a pore-crating mechanism initiated by self-propagation reactions between citric acids and nitrates. It is shown that the thermal conductivity k of powder compacts decreases sharply down from 1/10 to 1/32 of that of its single crystal bulk. as compact porosity increases from 60% to 95%. Therefore thermal barrier coatings (TBCs) of La2(CexZr1-x)2O7 with such nanoporous structures by an appropriate processing may work with quite a high insulative performance and very promising for TBC applications of high-efficiency and large propulsion engines.
Effect of Al2O3 on the Glass-Ceramics of CaO-SiO2-MgO-Al2O3 System Based on BOF Slag
Authors: Dai Wen Bin , Li Yu , Zhou Yuan Yuan , Cang Da Qiang , Fan Yong
Published: November 2013

Directly recycling residual iron element in modified BOF slag after reduction and manufacturing glass-ceramics from these remaining inorganic slag materials is an effective way to reuse the waste heat and slag materials of hot BOF slag. In the glass-ceramics, the Al2O3 has an important influence on the slag viscosity and the physical and chemical properties of glass-ceramics. In this paper, glass-ceramics with a basicity of 0.7 and a MgO content of 9~12% were prepared by using chemically pure reagents according to the CaO-SiO2-MgO phase diagram, and the effect of different Al2O3 content on the parent glass crystallization and glass-ceramic performances was studied. Results show that the flexural strength of glass-ceramics is mainly affected by the sintering shrinkage. When the weight content of Al2O3 exceeds 15%, both the flexural strength and the shrinkage rate reached the maximum, and dense microstructure was obtained. In addition, the original dominant crystal structure is affected while Al2O3>12%, with the anorthite crystal phase appearing consequently.
Fabrication and XRD Study of Lithium Silicate by Solid-State Reaction
Authors: Cao You Dong , Hu Jin , Tang Hua , Wang Yu Tian , Zhang Wei Jun
Published: November 2013

At present, solid-state reaction, precipitation method and sol-gel method are applied to fabricate lithium silicate. Solid-state reaction has the advantage of short reaction time, simple process and less impurity phase in comparison with other method. So in this paper fabrication of lithium silicate by solid-state reaction was investigated systematically. Thermogravimetric analysis, differential scanning calorimetry and XRD analysis were carried out systematically in this paper. The reaction process and mechanism at different temperatures and the effects of the reaction temperature, Li:Si molar ratio and heat preservation time on the lithium silicate phase were discussed. Experimental results showed that the mixture were sintered at 900°C for 2h, there would have relatively high content of lithium silicate phase. And reunion is not serious that is benefit of grinding. While the Li:Si molar ratio was 4:1, there would have relatively high content of lithium silicate phase. While the Li:Si molar ratio was 5:1, the lithium silicate phase was severely agglomerated.
Preparation and Mechanical Properties of TiN-Al2O3 Refractory Composites
Authors: Liu Hai Tao , Fang Ming Hao , Huang Zhao Hui , Ji Hai Peng , Min Xin , Liu Yan Gai , Wu Xiao Wen
Published: November 2013

TiN-Al2O3 bulk composites were prepared by pressureless sintering of the as-synthesized powder products obtained by aluminothermic reduction-nitridation of aluminum dross and rutile. The effects of temperature on the densification behaviour and mechanical properties of TiN-Al2O3 composites were studied. Results showed that the bulk density of the TiN-Al2O3 composites increased with the elevated sintering temperature. When the temperature arrived at 1500 °C, the flexural strength and fracture toughness reached the highest values (201.48 MPa and 4.11 MPa·m1/2, respectively).
Determination of Coating Thickness by Crater Grounding Method
Authors: Li Xue Jiao , Zhang Cheng , Zhang Na , Miao Shu Ting , Guo Dong Li , Zhang Llian Hui
Published: November 2013

Coating thickness plays an important role in the performance of coated tools and machine parts. In the paper, a straightforward and simple method-crater grounding method is introduced to measure Zn coatings thickness. Coating section observation measurement are used to test the thickness, and the comparative result show that crater grounding method is accuracy vary within a certain error range. The influencing factors of this measuring method is analyzed in this paper.
Study on the Performance of Aluminum Thick Film Contacts for Silicon Solar Cells
Authors: Fu Ming , Li Hong Yong , Jin Gong Lei , Fan Lin , Chen Dong , Feng Zhao
Published: November 2013

Aluminum rear contacts of silicon solar cells are made commonly by screen-printing aluminum paste and sintering process. Aluminum thick film contacts have a direct effect on photoelectric properties of solar cells, like open circuit voltage (Voc), short circuit current (Isc), conversion efficiency (η), etc. The principle of Al-back surface field (BSF) has been studied in this paper. With thermal gravimetric analysis and differential scanning calorimetry (TGA-DSC) method, the chemical reactions between aluminum thick film and silicon substrate during heat treatment have been investigated. The microstructure of aluminum thick film contacts were analysed by SEM. The electrical properties of Al-BSF are improved by adding a proper amount of nano silicon to the aluminum paste.
Research Progress in Laser Clad Nickel-Based Alloy Coatings
Authors: Yu Hui Jun , He Ting , Chen Chuan Zhong
Published: November 2013

Laser cladding, as a newly developed rapid solidification technique, is to cover a particular part of the substrate with another material that has superior properties, producing a metallurgical bond between the two materials with minimal dilution of the clad layer by the substrate. In this paper, the research progress in laser clad nickel based alloys is reviewed. The microstructures and wear resistance of the coatings are introduced, the main problems and some solutions of the laser cladding are analysized, and the development tendency and application prospect of laser cladding is also pointed out.
Fabrication and Plasmas-Relevant Properties of B4C/Cu Coating FGM
Authors: Sun Chuan , Li Yun Kai , Wang Hu , Ge Chang Chun
Published: November 2013

in this work, two kinds of boron carbide coating based on copper substrates, which are non-FGM B4C/Cu coating and FGM B4C/Cu coating, have been fabricated successfully. It is found that the chemical sputtering yield of B4C measures by LAS2000 apparatus is much lower than that of SMF800 graphite under the conditions of 3keV, 4.6E 15D+ /s/cm2 irradiation, and that FGM-B4C coating has much better performance than non-FGM-B4C coating in thermal shock tests. Thermal desorption performance and physical sputtering damage after plasma irradiation are also evaluated.
On the “Ceramic Constrained by Metal” Composite Materials
Authors: Sun Chuan , Li Yun Kai , Wang Hu , Wan Ming Ming , Wang Yun Fei , Jiang Quan Zhen
Published: November 2013

Ceramics are widely used in every field of contemporary industrial because of its many excellent properties. However, its mechanical property is great brittleness and small toughness for the characteristics of internal chemical bond, which restricts its application range to a large extent. Therefore, how to improve mechanical properties of ceramic materials has been attracted a great attention in the relevant area. For ceramics using at room temperature, a method which can avoid brittle failure by metal confinement outside of ceramics is given. And the feasibility of this method is discussed. Three point bending tests were conduct on ZrO2 ceramics with and without lateral confinement separately. Base on the much of experimental conclusion, the bending strength of ceramic with lateral confinement was improved largely.
Preparation of Graphene Nanosheets/Copper Composite by Spark Plasma Sintering
Authors: Qu Dong , Li Fang Zhi , Zhang Hai Bin , Wang Qian , Zhou Tian Liang , Hu Chun Feng , Xie Rong Jun
Published: November 2013

Graphene nanosheets (GNS)/copper composite has been prepared by spark plasma sintering (SPS). Microstructure of the sintered composite was characterized using scanning electron microscopy (SEM). Thermal conductivity and electrical resistivity properties are evaluated through laser flash apparatus and physical property measurement system. The obtained GNS/copper composite shows a layered structure. The GNS/copper composite prepared by SPS have an anisotropy of thermal conductivity and electrical resistivity.
The Effect of Ball Milling on the Electrochemical Behavior of Silicon Composite Electrode
Authors: Wen Zhong Sheng
Published: November 2013

Silicon material possesses the highest theoretic capacity (4200mAh/g, ten times of the capacity of commercialized carbon anode materials) of all known anode materials for lithium ion batteries and thus receives lots of attention to date. Silicon-containing composite electrode for lithium ion batteries was prepared by high-energy ball milling process. The microstructure and morphology of silicon electrode was investigated in detail. The effect of the structure transformation of the electrode by ball milling on the electrochemical behavior was systematically analyzed. Electrode precursors after a mediate ball milling time of 45min is beneficial to get a better cycling performance, due to the well distributed and less destroy of Carboxyl Methyl Cellulose (CMC). Weak lithium insertion into CMC occurs unavoidably in the charging-discharging process of the composite electrodes, which should be the main reason for the sudden disability of electrode. The electrochemical properties can get a dramatic enhancement within voltage window of 0.02-1.5V. Excellent cyclability with high capacity retention above 1800mAh/g after 40 cycles could be gained by controlling the ball-milling time and the voltage windows. It might be a feasible way to obtain satisfactory cyclability for high capacity anode materials.
Large Remanent Polarization of Bi4Ti3O12 Films by Ho3+ Substitution
Authors: Chen Min , Mei X.A. , Huang C.Q.
Published: November 2013

Ho-doped bismuth titanate (Bi4-xHoxTi3O12: BHT) and pure Bi4Ti3O12(BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25, 1.0, and 1.25, the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75, the current-voltage characteristics showed simple ohmic behaviors and their P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BHT Fims with x=0.75 were above 30μC/cm2 and 60KV/cm , respectively.
Nonlinear Magnetostrictive Effect of Magnetorheological Elastomers
Authors: Sun Shu Lei , Peng Xiong Qi , Guo Zao Yang
Published: November 2013

Magnetorheological elastomers (MREs) are a class of smart composites whose mechanical properties can be obviously changed under different magnetic field. Only a few works study its magnetostrictive property, which describes the changes in dimensions of a material in its magnetization. Magnetostriction in the ferromagnetic particle is also called eigenstrain in MREs. It is modeled using the nonlinear function of the magnetization in this article. The eigenstrain due to the magnetostriction is incorporated in the structure of the MREs using a generalized Hookes Law. By means of initial strain, a finite element simulation is presented to describe the magnetostriction of MREs. The results show that the magnetostriction along the magnetic field depends on the magnetization and the volume fraction of particles. As an application, we will present numerical simulations for a magnetostriction and compare these results with measured data.
First-Principles Study of Polarization Behavior in BaTiO3/PbTiO3 Ferroelectric Superlattices
Authors: Zhu Zhen Ye , Bai Jing , Lu Fei , Wang Qian
Published: November 2013

We performed the first principle calculation to investigate the polarization behavior of BaTiO3(BTO)/PbTiO3(PTO) superlattices with a period-5 superlattice model. The results show that when BTO proportion increases, values of c/a increase and polarizations decrease. In BPT superlattices, polarization in each local layer keeps a constant value, indicating that short-period BPT superlattices can be approximately considered as a single ferroelectric material. Moreover, from analysis of the electrostatic model, we know the directions of internal electric fields in BTO and PTO layers are opposite. Internal electric field in PTO layer leads to polarization loss in this layer, but polarization in BTO layer is enhanced by internal electric field.
Synthesis and Physical Properties of Graphene Nanosheets Reinforced Copper Composites
Authors: Wei Bing Wei , Qu Dong , Hu Chun Feng , Li Fang Zhi , Zhou Tian Liang , Xie Rong Jun , Zhou Zhi Ming
Published: November 2013

Cu/graphene nanosheets composites were fabricated at 800°C by the hot-pressing method using Cu and graphene as initial materials. Graphene content was 1 wt. %-5 wt. %. The fracture morphology and physical properties of the composites were investigated. It was found that the relative density increased with the increment of graphene content from 1 wt% to 5 wt. % with reaching its highest level (96.68%) at 5wt. %. The composites have the anisotropic property which is vertical to the direction of pressure is higher than parallel to the direction of pressure. With the increasing of graphene content, the thermal conductivity property and the electronic conductivity decrease first and then increase with the minimum thermal conductivity and electric conductivity at 3wt%~4wt%.
Influence of the Particle Size of LDPE on the Performance of Cu/LDPE Composites
Authors: Tang Ying , Wang Yun , Xia Xian Ping
Published: November 2013

The Cu/LDPE composites were characterized through the tests of micro-structure, mechanical property, surface hydrophilicity and releasing rate of cupric ions, in order to study the influence of the particle size of LDPE on the performance of Cu/LDPE composites. The results indicate that, with decreasing of the particle size of LDPE, Cu/LDPE composites have greater value of elongation at break and releasing rate of cupric, but smaller value of tensile strength and elasticity modulus, and the influence on surface hydrophilicity and crystalline is little. It is considered that the influence of the particle size of LDPE on the performance of Cu/LDPE composites results from the difference of both the molecular weight of LDPE and the dispersion uniformity of copper in LDPE.
Improving the Dispersity and DC Breakdown of MgO/LDPE Nanocomposite by Adding EVA
Authors: Zhao Hong , Peng Si Yuan , Yang Jia Ming
Published: November 2013

To improve the agglomerate phenomena of polarity nanosized MgO-filler in non-polar low density polyethylene (LDPE) matrix, in the composite (MgO/LDPE) master batch preparation process, adding a certain amount of ethylene-vinyl acetate copolymer (EVA), in order to improve the compatibility of nanoparticles and matrix materials. The dispersion states of MgO in the MgO/LDPE and EVA/MgO/LDPE composite material was evaluated by using scanning electron microscope (SEM), results shown that compared with MgO/LDPE nanocomposite, the dispersion of EVA modified MgO/LDPE is better and the agglomerate phenomena is not seen. DC breakdown tests shown that EVA modified MgO/LDPE compared with other several kinds of materials (LDPE; EVA/LDPE; MgO/LDPE and EVA/MgO/LDPE); the DC breakdown strength has improved significantly.
Dielectric and Energy Storage Properties of Polyvinylidene Fluoride/Barium Titanate Nanocomposites
Authors: Li Yan Xia , Xie Jin Long , Chu Zhen Ming , Wang Xu Sheng , Yao Xi
Published: November 2013

The combination of nanoparticles with high relative permittivity and polymers with high dielectric strength offers a potential to obtain processable nanocomposites with high dielectric performance. In this work, polyvinylidene fluoride (PVDF)-barium titanate (BT) nanocomposites were prepared by spin-coating technique. The surface of BT nanoparticles was treated by titanate coupling agent NDZ101. The dielectric and energy storage properties of the system were studied as a function of BT content. The experimental results showed that the dielectric constant of the nanocomposites increased with the increase of BT content. Although pure PVDF material has the strongest dielectric breakdown strength, the discharged energy storage density Ue of the nanocomposites was greatly improved from 2.8 J/cm3 in pure PVDF film to 6.2 J/cm3 in PVDF/20 wt% BT film; due to larger polarization of the nanocomposite.
Preparation and Properties of Transparent Side-Chain Fluorinated Polyurethane Elastomers
Authors: Zhang Ying Qiang , Zhong Chong Zhe , Xu Wei , Wu Zhen , Zhang Yu , Jin Zhi Lan
Published: November 2013

Transparent side-chain fluorinated polyurethane (SC-FPU) elastomers were prepared by using side-chain fluorine-containing polyether polyol, N210, isophorone diisocyanate (IPDI), and chain extender as main materials through prepolymerized method. The Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), tensile testing and contact angle analyzer were used to investigate the chemical structure, heat resistant, tensile properties, and surface property of SC-FPU elastomers with different fluorine content. The results indicated that SC-FPU elastomers had good heat resistant, mechanical, and surface property. The fluorine content had more influence on the properties of SC-FPU elastomers.
An Electrochemical Impedance Spectroscopy (EIS) Study of Zn-Doped Li (Ni1/3Co1/3Mn1/3) O2 Cathode Materials in the First Delithiation Process
Authors: Zheng Lu , Liu Liang Bin , Zhou Xiao Jing , Guo Yu Zhong
Published: November 2013

Li (Ni1/3Co1/3Mn1/3) O2 cathode materials doped by Zn were synthesized by a co-precipitation routine, the first delithiation process of the samples with 0-4wt% of Zn doping were studied by electrochemical impedance spectroscopy (EIS) under the polarized voltage of 2.8-4.6V. The fitting results based on EIS data indicate that delithiation reactions happen within the voltage range of 3.7-4.4V ; The resistances of SEI film and charge transfer are both decreased significantly, whereas Li+ diffusion ability through layered crystalline lattice is improved largely with the increase of zinc doping from 0 to 4wt%.
Preparation and Electrochemical Performance of SnO2/C-La0.3Sr0.7MnO3 Composites for Li-Ion Anode
Authors: Yin Yu Xin , Ruan Ding Shan , Chang Mei Yan , Hou Feng , Wang Hong Xia
Published: November 2013

Carbon-coated SnO2 particles (SnO2/C) were first synthesized by hydrolysis of SnCl4 in the sucrose solution at 85 °C, where sucrose is the carbon source. These particles were then mixed with La0.7Sr0.3MnO3 (LSM) through a suspension stirring process to form SnO2/C-LSM composites. The results of SEM and EDX show that LSM particles are distributed in SnO2/C uniformly. Galvanostatic discharge-charge measurement was used to test the electrochemical performance of SnO2/C and SnO2/C-LSM. It was found that the specific reversible capacity increased from165 mAh/g for SnO2/C to 270 mAh/g for SnO2/C-LSM after 50 cycles. This improvement may be attributed to the lower charge transfer resistance and higher electronic conductivity resulted from introducing LSM.
Role of the Mg/Al Atomic Ratio in Catalyst Support for NOX Storage/Reduction
Authors: Zhao Na , Hu Jin , Zhang Wei Jun , Wang Yu Tian
Published: November 2013

Abstract. Mg-Al-O catalyst support prepared by thermal decomposition of Mg/Al hydrotalcite precursors that obtained by coprecipitation method with different Mg/Al atomic ratios of 1.0, 2.0 and 3.0. The samples characterized by XRD and TG-DSC. The results show that the hydrotalcite performance have high crystallinity with the Mg/Al atomic ratio of 2:1 and 3:1; It can be clearly observed the diffraction peaks of MgO after calcined at 500°C, and shows highest crystallinity of MgO with Mg/Al atomic ratio of 3:1, but we can’t observed the diffraction peaks of Al2O3 because of high dispersity; TG-DSC analysis shows that hydrotalcite has chemical decomposed at 443°C, and the quality lossed 32.97%, this indicates it transform the most of hydrotalcite into MgO at this temperature.
Microwave Sintering and Electric Properties of ZnO Varistor Ceramics
Authors: He Xin Xin , Gan Guo You , Yan Ji Kang , Du Jing Hong , Zhang Jia Ming , Liu Yi Chun , Yi Jian Hong , Fan Mao Yan
Published: November 2013

The ZnO varistor ceramics were fabricated through microwave sintering at 800~1150°C using ZnO powder doped and undoped TiO2 prepared by planetary ball mill. And the effects of milling time, sintering temperature and doping on microwave sintering technique have been studied. The result shows that the powder is more homogeneously and with smaller particle size with the increasing of milling time, therefore the electric properties is improved. However the particle size and the electric properties tend towards stability after 20h milling time. The density and electric properties increase with the increasing of sintering temperature, but decrease sharply at 1100°C, so the best sintering temperature is 1100°C. Doping TiO2 improves the electric properties of ZnO, however the electric properties decrease with more than 2.5% doping.
Phase Structure of Nanocrystalline BaTiO3 Powders via One-Step Solvothermal Route
Authors: Zhang Hui , Wang Xiao Hui , Shen Zheng Bo , Hao Ya Nan
Published: November 2013

5 nm BaTiO3 powder has been successfully prepared by the one-step solvothermal method. The different grain size BaTiO3 powders have been achieved after calcining the 5 nm Nanocrystalline BaTiO3 powders at 700°C, 850°C and 950°C for 3 h. In-situ heating Raman spectroscopy revealed the dispersive phase transition character in the nanocrystalline BaTiO3 powders. As the BaTiO3 grain size decreases, wider phase transition temperature and the Raman intensity becomes weak. The BaTiO3 powders of the 5 nm nanocrystalline exhibited the similar phase transformations from rhombohedral to orthorhombic to tetragonal to cubic transitions as those in the coarse BaTiO3 ceramics.
Preparation of Acicular-Like ZnO Nanostructured Powder Using Ball Mill Zinc Powder by Hydrothermal Method
Authors: Peng Wei Xiao , Wang Kai Jun , Hu Jin , Wang Yu Tian
Published: November 2013

In this paper, we demonstrated the acicular-like ZnO nanostructure powder were prepared by hydrothermal method. We used the industrial aerosol elemental zinc powders through high energy ball mill, and then took ball mill zinc powder into autoclave reactor direct synthesis high length to diameter ratio of acicular-like ZnO nanostructure powder. The samples phase were studied by XRD, the morphology of the sample were observed by SEM, the samples of luminous performance were studied by Fluorescence spectrophotometer. When the hydrothermal temperature is 200°C, hydrothermal time is 24 h, mineralizer of NaOH concentration is 1 mol/L, the samples were washed by alcohol and then dried at 80°C for 3 hours. We had synthesized the high dispersion, high length to diameter ratio up to 50 acicular-like ZnO nanostructure powder.
Photocatalytic Properties of (Fe, N)-Codoped TiO2
Authors: Tang Wan Xia , Ni Er Xin , Yuan Jun , Yan Ji Kang , Yang Gang , Shi Zhe , Gan Guo You , Du Jing Hong , Zhang Jia Min , Liu Yi Chun , Yi Jian Hong
Published: November 2013

Fe, N)-codoped TiO2 were prepared by calcining the Fe-doped TiO2 samples accomplished by precipitation method in the nitrogen atmosphere, and the photocatalytic properties of (Fe, N)-codoped TiO2 at different temperatures were investigated. The samples were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and ultraviolet-visible (UV-vis). The results show that the (Fe, N)-codoped TiO2 powder samples calcined at 600°C are dispersed well with more hydroxyl groups on its surface. The absorption edge of the (Fe, N)-codoped TiO2 is 429nm due to the effects of mixed crystal, which means the improvement of photocatalytic capability.
Study on the Second Phases of (Y,Nb)-Codoped TiO2 Ceramic
Authors: Ni Er Xin , Tang Wan Xia , Zhang Song Lin , Yan Ji Kang , Gan Guo You , Yang Gang , Shi Zhe , Yi Jian Hong
Published: November 2013

Microstructures and crystal structures of the second phases YNbO4 and YTiNbO6 in (Y,Nb)-codoped TiO2 ceramics were investigated at different sintering temperature and calcination temperature. The (Y,Nb)-codoped TiO2 ceramics and the second phase ceramic samples were prepared by the traditional electronic ceramic process. The microstructure, chemical composition and crystal structures of samples were characterized by SEM, EDS and XRD. The results show that there exist second phases of YNbO4 and YTiNbO6 in (Y,Nb)-codoped TiO2 ceramic. With the sintering temperature and calcination temperature rising, the second phase YNbO4 will transmit to YTiNbO6.
Pore Controllable Regulation and Laccase Immobilization of Hollow Mesoporous SiO2/Fe3O4 Microspheres
Authors: Li Qun Yan , Zhu Qing Qiang , Wei Qi , Nie Zuo Ren
Published: November 2013

Hollow magnetic mesoporous SiO2/Fe3O4 microspheres with different mesopore sizes were synthesized by a simple multi-step solution growth process. In the experiment of coating mesoporous SiO2, cetyltrimethylammonium bromide (CTAB) was used as surfactant and two swelling agents, decane and 1, 3, 5-trimethylbenzene (TMB), were used as swelling agents alone or together with different sequence. The results showed that the magnetic mesoporous SiO2/Fe3O4 microspheres have a saturation magnetization of 13.6 emu·g-1 and a low coercivity (50 Oe). Different adding form of swelling agents had great effect on the microstructure of mesoporous SiO2/Fe3O4 microspheres. The mesoporous SiO2/Fe3O4 microspheres obtained by using two swelling agents together had better mesoporous properties. The mesoporous SiO2/Fe3O4 microspheres exhibited high surface area (850 m2·g-1), large peak pore (3.11 nm), high pore volume (1.23 cm3·g-1). Moreover, the composite microspheres had larger adsorption amount (276 mg/g) and quicker adsorption rate (0.178 g/ (mg·h)) of laccase.
High Frequency Magnetic Properties of A Composite Material Prepared from Z-Type Hexaferrite and Bi2O3
Authors: Cao Zhen Hua , Han Man Gui , Guan Meng Ran , Song Zhen Jiang , Deng Long Jiang
Published: November 2013

The composite materials are composed by Z-type hexaferrite and Bi2O3 by solid-state reaction method. Crystalline phase, microstructure and magnetic properties were measured by XRD, SEM, and VNA. The results showed that the sintering temperature and the content of Bi2O3 can effectively affected both uniformity and densification. What's more, Z-type hexaferrite mixed with proper content of Bi2O3 and sintered at a low temperature presented a high Q-factor in a high frequency.
Recovery of Precious Metals from Catalytic Converters of Automobiles by Hydrometallurgical Solid-Liquid Extraction Processes
Authors: Ilie Sorin , Miuţescu Adrian , Stoianovici Mircea , Mitran Gabriela
Published: November 2013

Today, among the basic requirements to be fulfilled by an automobile, those relating to environmental protection and recyclability are of great importance. This paper aims to present a new technological solution to recover rare metals - Platinum, Palladium and Rhodium - from automotive used catalysts, based on hydrometallurgical method of solid-liquid extraction. Following the theoretical and experimental researches, were established the technological sequences which must be carried for recovering precious metals from used automotive catalysts, in the pilot phase. The proposed technology has been applied for a quantity of 10 kg of used automotive catalysts of ceramic monolithic type, at the end of the recovery process and selective separation, resulting the following recovery efficiencies: 95 % for Platinum, 95 % for Palladium and 92 % for Rhodium. Finally, there were highlighted the main advantages of hydrometallurgical processes: versatility, economicity, high efficiencies and relatively low costs.
Installation for Determining the Nature of Excavated Material from the High-Capacity Belts of Mining Basins
Authors: Mihuţ Nicoleta Maria , Ianăşi Aurora Cătălina
Published: November 2013

This paper presents a method for determining the nature of the material (cool or sterile) running on high-capacity mining belt from basin of Oltenia. When an electromagnetic radiation that propagates in the air meets the separation surface with another environment suffers, among other things, the phenomenon of reflections (diffuse and specula). The intensity of reflected radiation depends on the optical surface properties of the encountered material. On this fact is based the possibility of identification of certain components of the mixture, if the optical properties are considerably different from other components. The method proposed in this paper is based on measuring the reflectance for different regions of the visible and near infrared spectra for samples of coal and sterile, dry and wet. The system for determining the nature of the excavated material mainly consists of an optical head (reflectance sensor) and an ultrasonic head (remote sensor). From experimental observations we see that the reflectance values of coal can be separated from those of sterile, which confirms the possibility of coal detection using the difference in reflectance. The limit of demarcation between reflectance of coal and different types of sterile is influenced by disturbing factors that occur at the plant operating detection under practical conditions such as: material humidity, the variability level of the material on the conveyor belt, the existence of a light background ambient. The method for determining the nature of material (coal or sterile) that circulates on high capacity belts creates real prerequisites of material excavated in conjunction with the possibility of taking quick and effective decisions in the distribution nodes from the coal careers.
Key words: electromagnetic radiation, reflectance, coal, remote sensor, detection.