bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Laser Melting of Metals: Desktop Machines Open up New Chances even for Small Companies
Authors: Hötter Jan Steffen , Fateri Miranda , Gebhardt Andreas
Published: December 2012

Additive manufacturing (AM) of metal parts by using Selective Laser Melting (SLM) has become a powerful tool mostly in the area of automotive, aerospace engineering and others. Especially in the field of dentistry, jewelry and related branches that require individualized or even one-of-a-kind products, the direct digital manufacturing process opens up new ways of design and manufacturing. In these fields, mostly small and medium sized businesses (SME) are operating which do not have sufficient human and economic resources to invest in this technology. But to stay competitive, the application of AM can be regarded as a necessity. In this situation a new desktop machine (Realizer SLM 50) was introduced that cost about 1/3 of a shop floor SLM machine and promises small quality parts. To find out whether the machine really is an alternative for SMEs the University of Applied Science, Aachen, Germany, designed, build and optimized typical parts from the dentistry and the jewelry branches using CoCr and silver material, the latter being new with this application. The paper describes the SLM procedure and how to find and optimize the most important parameters. The test is accompanied by digital simulation in order to verify the build parameters and to plan future builds. The procedure is shown as well as the resulting parts made from CoCr and silver material.
Response Surface Design for Remove of Copper from a Fe-Rich Pyrite Cinder
Authors: Liu Jian , Wen Shu Ming , Feng Qi Cheng , Chen Yu , Bai Shao Jun , Liu Dan , Wu Dan Dan
Published: December 2012

The study aims to remove copper from a pyrite cinders using chlorination roasting and optimizing the roasting parameters through response surface methodology (RSM). After a series of experiments, a quadratic model was suggested by RSM to correlate the variables to the copper volatilization ratio. The results indicate that the model is in good agreement with the experimental data and the dosage of chlorinating agent and roasting temperature play a key role in improving the volatilization ratio. The optimum conditions for remove copper from the cinders were identified as chlorinating agent dosage at 5%, roasting temperature at 1155.05 °C and roasting time of 10 minutes; under such a condition, an average copper volatilization ratio of 95.16% was achieved from the cinder.
Development of Novel Polyanhydride/Nanoceramics Composite Bone Grafts with Suitable Mechanical Strength and Long Durability
Authors: Hong Ding Wei , Lai Po Liang , Liu Tsang Hao , Chu I Ming
Published: December 2012

Different mole ratios of sebacic acid (SA) and 1,6-bis(p-carboxyphenoxy) hexane (CPH) were used to make copolymer. g-HAP, hydroxyapatite (HAP) nanopowder surface-modified by polycaprolactone (PCL), was added with the copolymer to enhance the mechanical strength. Because of surface erosion, polyanhydride sustained the mechanical properties with time. The degradation of copolymer did not cause obvious decline in pH, and was thus less harmful to the osseous tissue. HAP is the main components of human bone and a good osteoinductive substance to help bone mineralization. The result of our study showed that CPH:SA = 7:3 added with10 wt% g-HAP was the best condition with maximum compress strength of 103 MPa. With slow degradation rate and durable mechanical strength, the novel biomaterial was suitable bone repair in future clinical application.
The Preparation and Tribological Behaviors of Boron-Nitrogen Containing Modified Soybean Oil as Additives for Lubricating Oil
Authors: Fang Jian Hua , Chen Bo Shui , Wang Jiu , Wu Jiang
Published: December 2012

A type of new environmentally friendly lube additive----boron-nitrogen containing modified soybean oil was synthesized and characterized by infrared spectrum. Its tribological properties in rapeseed oil were tested on the four balls tester. The morphographies and tribochemical species of the worn surfaces were analyzed by means of Scanning Electron Microscope (SEM) and X--ray Photoelectron Spectroscope (XPS). The results show that the type of modified soybean oil as additives can obviously increase the load-carrying capacity 、anti-wear and friction-reducing abilities of rapeseed oil. Its lubrication mechanism is inferred that a high strength adsorption film and/or tribochemistry reaction film on the worn surface of the Al alloy due the carrier effect of a long chain rapeseed oil, high reaction activities of nitrogen, electron-deficient of boron and their synergisms.
Analytical Modeling and Parameter Extraction of Organic Thin Film Transistor: Effect of Contact Resistance, Doping Concentration and Field Dependent Mobility
Authors: Mittal Poornima , Negi Y.S. , Singh R.K.
Published: December 2012

For what is believed to be for the first time, the device physics based modeling approach to derive the generic model current equations of organic thin film transistor (OTFT) is described. Firstly, the current model equation is derived by considering the dependence of mobility on gate voltage and doping density, which is more realistic and relevant to organic materials containing TFTs. To model small molecule or polymer TFT, the potential drop across contacts is taken into account as contacts are not ohmic due to some morphological disorders. Further the effect of contact resistance is included and accordingly the generic model current equation is modified. It shows a good agreement of proposed current equation with simulated results which validates the proposed OTFT model from ohmic to saturation regime. Moreover, the analytical model is used to extract the contact and channel resistances in linear and saturation region and these resistances are verified through potential cut line (PCL) and transmission line methods (TLM). The extracted parameters are not only used to verify the electrical characteristics but also exhibit insight on contact potential, charge injection and transport phenomenon for organic TFT operation.
ANN-Based System Identification, Modelling and Control of Gas Turbines – A Review
Authors: Asgari Hamid , Chen Xiao Qi , Menhaj Mohammad Bagher , Sainudiin Raazesh
Published: December 2012

Gas Turbines (GTs) are the beating heart of nearly all industrial plants and specifically play a vital role in oil and power industries. Significant research activities have been carried out to discover accurate dynamics and to approach to the optimal operational point of these systems. A variety of analytical and experimental system identification methods, models and control systems has been investigated so far for gas turbines. Artificial neural network (ANN) has been recognized as one of the successful approaches that can disclose nonlinear behaviour of such complicated systems. This paper briefly reviews major ANN-based research activities in the field of system identification, modelling and control of gas turbines. It can be used as a reference for those who are interested to work and study in this area.
Wire Bond Shear Test Simulation on Hemispherical Surface Bond Pad
Authors: Sauli Z. , Retnasamy V. , Norhaimi W.M.W. , Adnan J. , Palianysamy M.
Published: December 2012

Wire bonding process is an interconnection method adopted in the semiconductor packaging manufactory. One of the method used to assess the reliability and bond strength of the bonded wires are wire bond shear test .In this study, simulation on wire bond shear test is done to evaluate the stress response of the bonded wire when sheared on a hemispherical surface bond pad. The contrast between three types of wire material:gold(Au), aluminum(Al) and copper(Cu) were carry out to examine the effects of wire material on the stress response of bonded wire during wire bond shear test. The simulation results showed that copper wire bond induces highest stress and gold wire exhibits the least stress response.
Characterization, Optical, and Theoretical Investigation of Arrays of the Metallic Nanowires Fabricated by a Shadow Deposition Method
Authors: Locharoenrat Kitsakorn , Mizutani Goro
Published: December 2012

We have fabricated Au, Cu, and Pt nanowires by using a shadow deposition technique. We have then investigated optical properties of these nanowires by studying the second harmonic generation (SHG) spectra. With experimental and theoretical studies, we have discovered that the surface plasmon resonance was served as an origin of the enhancement of the SH response from the metallic nanowires.
Simulation and Analysis of Three Finger Micro/Nano Gripper Using Different Materials
Authors: Ghanbari Ahmad , Qaredaghi Ehsan
Published: December 2012

In this paper, we investigate the three finger micro/nano gripper using piezoelectric actuator. A comparison of various materials as structural and actuator is presented. Different combination of Silicon, Quartz (SiO2), and Aluminium as structural material with PZT4, and PZT-5H as actuating material have been analysed. Results show that the combination of Aluminium with PZT-5H produces more displacement than the others.
Preparation and Gas Sensing Properties of 2,9,16,23-Tetra-Tert-Butyl-29H, 31H- Copper (II) Phthalocyanine LB Thin Films
Authors: Wang Si Yu , Xu Jian Hua , Yang Wen Yao , Chen Yan , Yang Ya Jie
Published: December 2012

A phthalocyanine derivative: 2,9,16,23-tetra-tert-butyl-29H,31H-copper(II) phthalocyanine (CuttbPc) was used as an optical gas sensor based on Langmuir-Blodgett (LB) films. Surface pressure-area per molecule (π–A) isotherms and Brewster Angle Microscopy (BAM) will show the process of the monolayer formation at the air-water interface. The responses of the thin films to various volatile organic compounds (VOCs) were recorded by UV-Vis absorption spectra and the morphological characterization was performed by Atomic Force Microscopy (AFM). The experimental results indicate that highly-ordered and uniform films can be prepared at about 33mN/m with the transfer ratio of 0.7. The results also demonstrated that CuttbPc LB films are promising to be applied into optical gas sensors for VOCs detection and recognition.
Heredity of the Structure and Properties of Grey Cast Iron Melted on a Basis of Steel Scrap
Authors: Janerka Krzysztof , Jezierski Jan , Bartocha Dariusz , Szajnar Jan
Published: December 2012

In this paper are presented the results of researches, obtained during cast iron melting on basis of steel scrap and a carburizer (without pig iron in solid charge). In the process of carburization, there were used the carburizers such as anthracite, natural and synthetic graphite, petroleum and cupola coke, as well as charcoal. The grey cast iron was produced, for which quantitative analysis of graphite precipitations was performed. It was noticed that in case of using anthracite as carburizer, the smaller graphite precipitations were obtained. In authors’ opinion they are consequences of anthracite structure, consisted of fine graphite flakes and phenomenon of charge materials features’ transfer into melted alloys (structure heredity).
Investigations on the Effect of Tool Speed and Feed Rate on the Friction Stir Processed AZ31B Magnesium Alloys
Authors: Pushpanathan D. Peter , Balamurugan K. Ganesa , Mahadevan K.
Published: December 2012

The friction stir processing is a solid state processing technique. The present study investigates the effect of process parameters like tool rotational speed and tool feed on the mechanical and tribological properties of friction stir processed AZ31B magnesium alloy. The experiments were conducted with 3 level 2 factors full factorial design with two replications. The responses were tensile strength, microhardness and wear. The investigation reveals that both the tensile strength and microhardness values were decreasing with decreasing grain size. The minimum wear rates were observed at higher hardness values.
Comparison of Bubble Electrospinning and Needle Electrospinning of Ethylcellulose Ultrafine Fibres
Authors: Vadodaria Ketankumar , STYLIOS George
Published: December 2012

Ethylcellulose (EC) is a biocompatible cellulosic derivative widely used in the drug industry.In the present work, EC nanofibres were electrospunusingethanol: toluene(40:60-by wt.) mixture system by both single needle electrospinning (SNE) and bubble electrospinning (BE) methods. Comparisons of the effect of the various process parameters such as needle/solution surface to collector distance, app. volt. and feed rate on fibre characteristics were studied. The optimum SNE feed rate comparable to BE was decided 1.5ml/hrafter comparing fibre diameter. Comparisons of these parameters revealed that fibre morphologiesfollows different trendsin SNE and BE.Average (Avg.) fibre diameters increased with increase in feed rate in SNE.As needle to collectordistance (NTCD)increased, theavg.fibre diameter decreased in SNE. However, in BE, fibre diameter increased with increase in solution surface to collector distance (STCD).Fibre diameter decreased in SNE with increase in app. volt.. However, in BE; initially the fibre diameter decreased and then increased with increase in app. volt.. These different trends in diameter of BE and SNE electrospun fibres are explained and discussed in the present article.
Stress Induced in Al2O3 Films as Deposited onto Al2O3TiC Substrate by RF Diode Sputtering
Authors: Panitchakan H. , Limsuwan Pichet
Published: December 2012

Al2O3 films were deposited onto Al2O3-TiC substrates by RF diode sputtering. The Al2O3 films were deposited at various substrate bias voltages from -80 to -180 V, sputtering powers from 4 to 8 kW and operating pressures from 20 to 30 mTorr. The stress induced in Al2O3 films was measured. The results show that the stress induced in all prepared Al2O3 films is tensile stress. The stress slightly increased with increasing substrate bias voltage whereas it increased linearly with increasing operating pressure. However, the stress was almost constant as the sputtering was increased from 5 to 8 kW and significantly decreased as the sputtering power was decreased below 5 kW.
Hydrogen Integration in Refinery Using MINLP Method
Authors: Masoumi Mir Esmaeil , Jahantighy Zahra Firooz
Published: December 2012

Hydrogen is an important utility in the production of clean fuels as low-sulfur gasoline and diesel. The combination of low-sulfur fuel specifications and reduced production of hydrogen in catalytic reformers make hydrogen management a critical issue. In this paper a systematic approach for the retrofit design of hydrogen networks in refineries was proposed. The methodology is based upon mathematical optimization of a superstructure and maximizing the amount of hydrogen recovered across a site. The techniques account fully for pressure constraints as well as the existing equipment. The optimum placement of new equipment such as compressors and purification units is also considered. Total annual cost and fresh hydrogen required by the refinery are employed as the optimizing objects. Equations obtained from superstructure method are solved with mixed-integer nonlinear programming of the general algebraic modeling system. In this work the Tehran refinery was considered as a case study. The results of optimization show that the 28% reduction was achieved in hydrogen production of north section and this is 35.7% for south section of refinery. Also adding the new hydrogen recovery unit in hydrogen network will cause 20% reduction in total costs of north and 31.2% in south sections.
Energy Saving in Electro-Hydraulic System Using a MIMO Fuzzy Controller
Authors: Pratumsuwan Pornjit , Hutamarn Santi , Po-Ngaen Watcharin
Published: December 2012

Energy saving in the electro-hydraulic system (EHS) that currently exists in most inverter used to adjust speed of the asynchronous motor (ASM) which drive a fixed displacement pump. The most controller commonly used control system such as PID and multi-input single-output (MISO) fuzzy controller. In this paper, a multi-input multi-output (MIMO) fuzzy controller is used to improve the energy saving performance of the EHS. The proposed controller is designed to control the pressure of the EHS to suit the actual needs of the load. The two inputs of controller received signals from the error and change in error of the load pressure of the EHS. For the two outputs of the controller, one output is used to control the inverter to adjust speed of an ASM which drive hydraulic pump, and one output that is used for control proportional pressure relief valve. The proposed controller was implemented to pressure control of compression machine. The experimental result showed that using a proposed controller can reduce power consumption was higher than compared with PID and MISO fuzzy controllers. Particularly, a MIMO fuzzy controller can reduce power consumption by up to 70.22% when compared to the conventional system.
Microwave-Assisted Synthesis of Ni/CNTs Nanocomposites for Hydrogen Production from Hydrolysis of NaBH4
Authors: Li Fang , Li Qi Ming , Kim Hern
Published: December 2012

Hydrogen production from NaBH4 hydrolysis is very important for environment-friendly fuel cells. Here Ni/CNTs nanocomposites were prepared by microwave-assisted method and used as the catalyst for catalytic hydrolysis of NaBH4. XRD and SEM characterization showed that uniform Ni/CNTs nanocomposites can be obtained through microwave heating and solvent optimization. Ni/CNTs nanocomposites exhibit excellent catalytic activity in the hydrolysis of NaBH4, i.e., the average hydrogen generation rate at 25°C is 840ml.min-1.g-1 for the CNTs-supported Ni/CNTs, while the hydrogen generation rate of 86ml.min-1.g-1 for unsupported Ni catalyst. Compared with the unsupported Ni catalyst, Ni/CNTs nanocomposites presented higher catalytic activity for hydrolysis of aqueous NaBH4 solution.
Dry Drawn Multiwall Carbon Nanotube Sheet as a Counter Electrode for Dye-Sensitized Solar Cells: Multilayer Optimization
Authors: Kuanyshbekova Zharkynay , Huynh Chi , Hawkins Stephen , Smagulov Dauletkhan , Malayev Samat , Zakhidov Anvar
Published: December 2012

We demonstrate the fabrication of dye sensitized solar cells using multiwall carbon nanotube (MWNT) sheets as a counter electrode with catalytic activity optimized by layering as an alternative to platinum deposited on fluorinated tin oxide (FTO). The sheets are drawn directly from a highly aligned forest of MWNTs grown on silicon by chemical vapor deposition. We used different number of MWNT layers on the FTO and pure glass. Cell performance was found to vary with the number of MWNT sheets. When using of 10 or more layers we can substitute the FTO with platinum catalytic particles.
Characterization of Size and Antiwear Ability of Molybdenum Disulfide Nanoparticles
Authors: Ziaie Elahe Ebrahimpoor , Hasani Sedigheh Sadegh , Tofigh Atefeh
Published: December 2012

In this paper, the results of a study about using Molybdenum disulfide nanoparticle in base oil, which is used for engine oil production, are presented. The size characterization and morphology of nanoparticles were determined by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X- ray diffractometry (XRD). Dispersion of nanoparticles in base oil was achieved by ultrasonic homogenizer and the antiwear ability was evaluated by four ball test.
Synthesis of CdS Nanoparticles by Sonochemical Reaction Using Thioasetamide as S2− Reservoir and in the Presence of a Neutral Surfactant, Dyeing of Cotton Fabric and Study of Antibacterial Effect on Cotton Fabric
Authors: Tabatabaee Masoumeh , Baziari Paria , Nasirizadeh Navid , Dehghanizadeh Hamed
Published: December 2012

Nano-sized cadmium sulfid (CdS) was synthesized successfully by a simple method using ultrasonic irradiation in the presence of polyethylene glycol (PEG 2000). X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure and morphology synthesized powder. The nanocrystaline of β-CdS was grown in face-centered cubic. The average particle size of synthesized CdS is ~25 nm. CdS suspensions have then been impregnated on cotton-based textile samples and the antibacterial activity of so-functionalized textiles has been studied with respect to E. coli. Results shows that CdS nanoparticles exhibit a strong antibacterial activity and can inhibit 97% of growth E. coli bacteria.
Synthesis and Magnetic Properties of SrFe12-XCoxO19 (x= 0- 2) Hexaferrite Nanoparticles
Authors: Shoushtari M. Zargar , Ghahfarokhi S E. Mousavi , Ranjbar F.
Published: December 2012

In this paper, a batch of M- type strontium hexaferrite samples with nominal composition of SrFe12-xCoxO19(where x= 0- 2), have been synthesized via sol- gel method. In the synthesis of samples, first a precursor gel was prepared, and then dry- gel was calcined at 1000°C for 2 hours to obtain the nano- SrFe12-xCoxO19. The XRD results revealed that for SrFe12-xCoxO19 samples with x≤0.5, all of them have single- phase hexaferrite structure and also this data suggests that the F 3+ ions are substituted by Co2+ ions in the crystallography sites of the SrFe12-xCoxO19, but for the samples with x>0.5, the second phase of CoFe2O4 is appeared and suggests that the Co2+ ions also make a distinct phase in the samples. The magnetic properties, such as saturation magnetization (Ms), magnetic remanence (Mr), magnetic coercivity (Hc), squareness ratio (Mr/Ms), crystalline anisotropy field (Ha), energy product [(BH)max] and the susceptibility χ as the derivative of M with respect to H of the upper branch of the hysteresis loop were discussed by measurements of M-H curves with vibrating sample magnetometer (VSM). The magnetic measurements revealed that the coercively (Hc) values of all the samples decrease with increasing dopant contents.
Glass Anatase Nanocrystal Composites and their Crystallization Kinetics
Authors: Paramesh Gadige , Varma K.B.R.
Published: December 2012

Nanocrystallization of anatase phase was established in BaO-TiO2-B2O3 glass system. Crystallization kinetics of anatase phase in these glasses were investigated using non-isothermal differential scanning calorimetry (DSC) at three different heating rates (10, 20 & 30 K/min). Scanning Electron Microscopy (SEM) carried out on heat treated (at 920 K) glasses confirmed bulk nucleation and three-dimensional growth. Johnson-Mehl-Avarami model could not be applied for this system suggesting considerable overlap of the nucleation and growth involving complex transformation process. However, modified Kissinger and Ozawa models were used to calculate the effective activation energy associated with anatase crystallization. The kinetic exponent n was found to be temperature dependent indicating the change in the crystallization mechanism. This was attributed to the high entropy fusion of anatase phase, fast crystallization rate and nano dimension of the anatase phase.
Thermal Effect on Dynamic Stability of Single-Walled Carbon Nanotubes in Low and High Temperatures Based on Nonlocal Shell Theory
Authors: Hosseini-Ara R. , Mirdamadi H.R. , Khademyzadeh H. , Salimi H.
Published: December 2012

This paper studies the thermal effect on dynamic stability of single-walled carbon nanotubes (SWCNTs) embedded in polymer matrix in low and high temperatures under impact loads. To this end, we present a nonlocal elastic shell model including thermal and small-size effects. Further, numerical calculations are presented for SWCNTs. Results show that the increasing in temperature field has the effect of increasing the dynamic buckling loads at low or room temperature. However, this effect leads to decrease the dynamic buckling loads at high temperature. In addition, it is observed that nonlocal dynamic buckling loads increase by an increase in the Neperian frequency.
Carbothermic Reduction of Mechanically Activated MoO3 to Synthesize Nano-Crystalline Metallic Mo
Authors: Khabbaz Sirous , Honarbakhsh-Raouf Abbas , Ataie A. , Saghafi M. , Nozari Amin
Published: December 2012

In this work, the synthesis of nano-crystalline molybdenum via mechanical activation and subsequent heat treatment using graphite as the reducing agent has been studied. XRD analysis showed that in a 50 hours milled sample, the first step of the reduction took place and MoO3 reduced to nano-crystalline MoO2 with a mean crystallite size of 34 nm. The resultant MoO2 converted to molybdenum when the 20 hours milled sample was heat treated at 1000 °C for 1 hour. FESEM images confirmed the formation of uniform particles of molybdenum after heat treatment.
Control of Pore Size of High Purity Nanoporous Silica Formed from Volcanic Ash Deposit Shirasu
Authors: Sato Kosei , Kokubu Toshinori , Nishioka Kensuke
Published: December 2012

High purity nanoporous silica was fabricated using Shirasu volcanic ash as a starting material. The starting materials were placed into a platinum crucible and were melted at 1400°C. A mother glass was formed by quenching the melt in pure water. Leaching was performed by immersing the mother glass into an HCl solution. Nonsilica phases formed by phase separation in the mother glass were leached out with acid solution. The obtained porous silica was more than 99% pure and had pore size smaller than 2 nm. In order to control the pore size, post heat treatment was performed. The pore size could be controlled from 3.1 to 21.7 nm by changing the post treatment temperature.
Optimization for Biodegradability of Polylactic Acid by Using Taguchi Design of Experimental Methodology
Authors: Wang Shu Wen , Su Te Li
Published: December 2012

The purpose of this research is to raise the initial hydrolysis rate of polylactic acid (PLA) during the entire decomposing process, and then enhance the decomposition rate of PLA in natural environment. This research uses Taguchi method to do the parameter design of PLA hydrolysis. And then main effect analysis is applied to find out the significant factors and the optimal hydrolysis conditions for PLA. By the results of the confirmation experiments, the optimal conditions of the PLA hydrolysis rate got by these experiments are all located on the 95% confidence interval. This indicates that these experiments are with reproducibility and reliability.
Laboratory Study on the Effect of Nano TiO2 on Rutting Performance of Asphalt Pavements
Authors: Tanzadeh Javad , Vahedi Fariborz , Kheiry Pezhouhan T. , Tanzadeh Rashid
Published: December 2012

Modiﬁcation of the asphalt binder is one approach taken to improve Asphalt pavement performance. Rutting is one of the most important factors that could reduce the life of asphalt pavements.Nowadays, the application of nanotechnologyto achieve materials that are more resistant is expanding in asphalt pavement thatNano-TiO2 is among the most exciting and promising classes of materials discovered recently. The purpose of this study is laboratory research on the effect of Nano-TiO2 in improving Bitumen property and rutting resistance in Asphalt pavement under dynamic loading. For this purpose, the wheel-tracking test was carried outon ordinary and Nano-TiO2 modified hot mix asphalt samples.The results illustrate that using Nano-TiO2in asphaltbinder samples cause to an improvement in ruttingdepth in comparison with theordinarymixtures.
Optimization for Preparation of High Density Alumina Ceramics with Ultrafine-Grained Structure by a Fast Sintering Method
Authors: Huang Wei Jiu , Wu Gui Sen , Meng Fan Cheng , Ye Feng
Published: December 2012

The preparation of ultrafine-grained alumina ceramics by the fast sintering technique Self-propagating High-temperature Synthesis plus Quick Pressing (SHS-QP) method was reported. The reaction heat generated by combustion reaction was applied to act as a high temperature source. An alumina compact was loaded inside the combustion reactants, which form a “SHS-furnace”, and great mechanical pressure was applied when the temperature reached the maximum. Dense ultrafine-grained alumina ceramic was prepared using a lower heating rate (900 °C /min), and the effects of sintering time, and pressure on the densification and grain size were discussed. Within a short sintering time of 3 min, full-density alumina ceramics with ultrafine-grained structure are obtained under a pressure of 120 MPa.
Preparation and Properties of the Ferroelectric Materials Based on BIT
Authors: Zhang Na , Zhang Cheng , Li Xue Jiao
Published: December 2012

In this paper, firstly, the BIT powder was synthesized by ball grinding and the sequent calcinations, starting from TiO2 and Bi2O3. Typically, the grinding technique was facile to form the smaller particles, and the sintering process was utilized to obtain the pure BIT phase. The influence of heated temperature, time and the content of doped rare earth metal (La, Y) on BIT matrix have been investigated in details. The procedure consisted of being pressed, sintered, silver coated to obtain the BIT ferroelectric blocks. Lastly, the BIT density and ferroelectric properties of obtained blocks have been studied. The results showed that via the milling process and the addition of La and Y elements, BIT could be shaped at the lower temperature. Meanwhile, the ferroelectric properties have been improved.
Ferroelectric Properties of Bismuth Titanate Ceramics by Tb3+,4+/V5+ Substitution
Authors: Mei X.A. , Liu Rui Fang , Huang C.Q. , Liu J.
Published: December 2012

The Ferroelectric properties and Microstructures of Bi3.3Tb0.6Ti3O12 (BTT) and Bi3.3Tb0.6Ti2.97V0.03O12 (BTTV) ceramics prepared at 1100°C by a conventional ceramic technique were investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BTT ceramics are 23µC/cm2 and 80kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTTV ceramics up to 35μC/cm2, which is larger than that of the BTT ceramics. Therefore, co-sustitution of Tb and V in Bi4Ti3O12 (BIT) ceramic is effective for the improvement of its ferroelectricity.
Electrical Characterization and Microstructures of Bi3.25Er0.75Ti3O12 and Bi2.9Er0.75Ti2.97V0.03O12 Thin Films
Authors: Huang C.Q. , Liu J.G. , Mei X.A. , Liu J.
Published: December 2012

Bi3.25Er0.75Ti3O12(BET) and Bi3.25Er0.75Ti2.97V0.03O12(BETV) 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. The experimental results indicated that Er doping into Bi4Ti3O12 (BIT) also result in a remarkable improvement in ferroelectric property. The remanent polarization (Pr) and coercive field (Ec) of the BET film were 17 μC/cm2 and 80 kV/cm, respectively. Furthermore, V substitution improves the Er value of the BETV films up to 28 μC/cm2, which is much larger than that of the BET film.
Crystallization and Photocatalytic-Activity of TiO2 Doped with Metal Ions Prepared by Adsorption Phase Synthesis
Authors: Wang Ting , Mao Yan Dong , Tang Fang Peng , Xing Jun , Wu Li Guang
Published: December 2012

TiO2 photocatalysts doped with different metal ions were prepared by adsorption phase synthesis. The influence of different dopant metal ions with various concentrations on the crystallization of TiO2 was ex-plored by XRD. Then photodegradation experiments of methyl-orange were employed to evaluate the activity of these photocatalysts. The results indicated that the crystallization of TiO2 was restricted after doping, due to replacement of Ti4+ in TiO2 lattice structure by other metal ions. And the restriction became stronger with radius and concentration of doping ions increasing. There was an optimum dopant concentration appeared during preparation of TiO2 doped with Cd2+ and Fe3+. When dopant concentration was less or more than this optimum value, the photocatalytic activity of TiO2 doped with metal ions was lower than that of TiO2 without doping. Since radius of Fe3+ was close to Ti4+, the influence of Fe3+ dopant concentration on crystallization and activity of TiO2 was more obvious than that of Cd2+ doping.
Influence of Heat Treatment on Lithium Orthosilicate Pebbles
Authors: Tang Hua , Wang Yu Tian , Zhang Wei Jun , Shen Li , Duan Yun Biao , Hu Jin
Published: December 2012

Abstract: The lithium orthosilicate pebbles was fabricated by melt spraying method with lithium carbonate (Li2CO3) and silicon dioxide (SiO2). By alter heat treatment temperature to study different particle sizes of lithium orthosilicate pebbles of strength and phase. Lithium orthosilicate pebbles which were heat treated by vacuum tube type furnace study change of phase ,by XRD to study the change of phase after the heat treatment and tested strength by universal testing machine. Heat treatment would alter strength and phase by vacuum tube type furnace.
Preparation of New Structural TiO2 Nanotube Arrays and Study of Photoelectric Properties
Authors: Wang Xiao Qiang , Wang Jian Min , Guo Jing , Li Yue Liu , Li Ming Ya
Published: December 2012

NH4F with ethylene glycol solution as the electrolyte, the anodic oxidation of titanium mesh surface in preparation of ordered TiO2 nanotube array. The structure, morphology and absorption properties of samples were characterized by XRD, SEM and UV spectrophotometer. The results show that, in a certain time range, nanotube length and diameter will increase with the increase of oxidation time. The best oxidation time is 60min. Ultraviolet visible spectrophotometer results show that, the optical band gap of samples is from 3.26-3.42eV. The photoelectric conversion characteristics of dye sensitized solar cell assembled with prepared nanotube arrays were tested.
Comparing Study on Transmittance of Four Dental All-Ceramic Core Material
Authors: Deng Bin , Xu Juan , Liang Li Min , Yi Yuan Fu , Shao Long Quan , Wen Ning , Gu Bin , Liu Yi Han , Lu Rong Jian , Chen Ji Hua
Published: December 2012

The purpose of this study was to compare the transmittance of four dental all-ceramic core materials at clinical recommendation thickness.Specimens with 10mm in diameter and 0.50.01mm in thickness,including IPS e.max Press,Zenostar Zirconia,Lava Zirconia and Upcera Zirconia,were fabricated.The transmittance of specimens were measured with PR2650 spectrophotometer and measurements were analysed statistically with SPSS13.0.Experimental results showed that they had significantly different transmittance.There was a decreasing order,IPS e.max Press Lava Zirconia Zenostar Zirconia Upcera Zirconia,which were 6.1136.750 for IPS e.max,1.6042.135 for Lava Zirconia,1.5782.117 for Zenostar Zirconia and 0.9951.265 for Upcera Zirconia.
The Mobility and Rheological Properties of Phenyl Silicone Rubber
Authors: Wu Zhen , Zhang Ying Qiang , Guo Qing
Published: December 2012

In this paper the mobility and factots affecting mobility of phenyl silicone rubber is studied. The results showed that the crystallinity of phenyl silicone rubber was declined because of the presence of phenyl and the higher the phenyl content, the lower the crystallinity when the phenyl content was low. The viscosity of the phenyl silicone rubber was rised as molar mass and phenyl content of the rubber was increased but the changes was not uniform. The viscosity of the phenyl silicone rubber was declined as temperature was increased and viscosity-temperature dependence of the high molar mass phenyl silicone rubber was larger. The influence of shearing on the viscosity and mobility of the phenyl silicone rubber were evident.
Study on Toughening of the Epoxy
Authors: Ouyang Chun Fa , Zhang Duo You , Gao Qun , Shi Yu Tao , Zheng Kang Sheng
Published: December 2012

Abstract. The effect of styrene-The effect of hydroxy-terminated polybutadiene liquid rubber (HTPB) and softened agent on the performance of epoxy resin are studied. The mechanical properties of the composites investigated and the toughening mechanism were studied trough the SEM. In the HTPB/epoxy resin composites, the hardness is reduced but the elongation and the shear strength increased . Added 20wt%HTPB, the breaking elongation can be up to 16.19% and the shear strength rise to 13.74MPa. From the images of the SEM, the globular and trumpet-like hole and shear zone can hinder the development of the cracks, thus increasing the toughness of the epoxy resint. In the softened agent/epoxy resin composites, The addition of the softened agent, the breaking elongation and the impact strength have increased. From the images of SEM,we found that ,with the addition of the softened agent ,the single phase structure turns to two-phase structure and the bicontinuous phase and the brittle fracture turns to ductile fracture.
Influence of PNA012 on Crystallization and Mechanical Properties of Polybutylene Terephthalate
Authors: Zhang Duo You , Liu Peng , Ouyoung Chun Fa , Gao Qun , Zheng Kang Sheng , Hu He Feng , Li Zhi Jie
Published: December 2012

PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 °C to 199.7 °C and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07°C to 125.94°C.
Preparation of Zeolite A from Natural Stellerite
Authors: Zhang Chun Ying , Chen Nan Chun , Zhang Xiao Hu , Tang Quan
Published: December 2012

Zeolite A was prepared from natural stellerite under hydrothermal conditions.The experiments were carried at different crystallization temperatures and times，the experimental results and synthetical factors were analyzed and researched. The end products have been characterized by using FT–IR, X–ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that zeolite A was synthesized on the condition of the crystallization temperature at 90~100°C and the crystallization time for 6 hours with 15% hydrochloric acid of stellerite modifying，according to certain proportion of stellerite.
Inhibition Effect of Sodium Nitrite and Triethanolamine for Uranium with Electrochemical Methods
Authors: Cai Ding Zhou , Sang Ge , Shuai Mao Bing
Published: December 2012

The corrosion inhibition effect of sodium nitrite (NaNO2) and triethanolamine (N(C2H4OH)3) for uranium was evaluated in 200 mg/L sodium chloride (NaCl) solution by linear polarization and potentiodynamic polarization. The results showed that NaNO2 predominatly acted to inhibit the anodic reaction for the electrochemical behavior of uranium. NaNO2 combined with N(C2H4OH)3 could reinforce corrosion resistance of uranium. Multi-function could be found from 20 g/L NaNO2 combined with 10 mL/L N(C2H4OH)3. Pitting corrosion on uranium surface could be effectively prevented by 1g/L NaNO2 combined with 10 mL/L N(C2H4OH)3. Auger electron spectroscopy (AES) and Raman spectrum analyses indicated that uranium oxide layer mainly contained uranium dioxide (UO2).
Synthesis of Submicron AlON Powder by Wet Chemical Processing
Authors: Ma Fei Zhong , Lei Jing Xuan , Shi Ying , Xie Jian Jun , Lei Fang
Published: December 2012

The single-phase Υ-AlON powders were synthesized from three different precursors: Υ-Al2O3+C, Al(OH)3+C, NH4Al(OH)2CO3+C at 1750°C by carbothermal reduction and nitridation . The effects of aluminium source and synthetic process conditions on the characteristic of Υ-AlON powders were investigated in order to optimize the preparation method. It was revealed that the wet chemical processing was helpful to reduce partical size. The median particle sizes (d50) of AlON powders synthesized from different precusors were 15.33 μm, 2.886 μm, 405.6 nm, respectively.
Fabrication of Highly Ordered Arrays of TiO2 Nanotubes on Ti Wires
Authors: Li Ming Ya , Wang Jian Min , Guo Jing , Li Yue Liu , Wang Xiao Qiang
Published: December 2012

Highly Ordered arrays of TiO2 nanotubes on Ti wire were prepared by anodic oxidation with ethylene glycol solution of NH4F electrolyte. The phase compositions of the samples were characterized using X-ray diffraction (XRD) analysis using Cu-Kα radiation. The microstructure was observed using scanning electron microscopy (SEM). Experimental results show that at the anode condition of 95V, 50°C, and then themal treatment at 550°C, the highly ordered anatase TiO2 nanotubes arrays arranged on the surface of Ti wire. The length of the nanotube achieved was about 31μm, the internal diameter and outer diameter of the nanotube was 127nm and 170nm, respectively.
Effects of the Ratio of Surface Protective Agent on the Preparation of Nano-Silver
Authors: Zhai Feng Rui , Liu Yi Ming , Yuan Jian Ping , Zhang Hong Wei , Yi Zhong Zhou
Published: December 2012

It has many advantages with liquid phase reduction method to prepare the nano-silver, such as experimental conditions are simple, low cost, energy-saving, etc.. At the same time, the nano silver powder prepared by this method has high surface activity, catalytic property and wide usage. In this paper, nano-silver powder was prepared by changing the amount of protective agents with chemical liquid phase reduction method. This paper focuses on the impact of the amount of protective agent on the nano-silver. In addition, we also analyzed the reaction temperature, PH value of solution, viscosity and electrical conductivity on the preparation of nano-silver. Finally, test results from the TEM shows that the nano-silver was prepared with smaller size, uniform size and good dispersion.
Reentry Trajectory Planning Based on the Secondary Reversal Dynamics for the Second Generation Reusable Launch Vehicles
Authors: Zhao Biao , Cui Nai Gang , Guo Ji Feng , Fu Yu
Published: December 2012

Based on secondary reversal reentry dynamics and the drag acceleration - energy (D-E) profile, a new reentry trajectory planning and guidance method is present. Since the D-E profile is obtained from interpolating the upper and lower boundary of the reentry corridor, it has the ability to guide the vehicle to the maximum down-range and cross-range. The secondary bank reversal mode is implemented to ensure terminal guidance accuracy and reduces the difficulty of tracking control. The planning taking the vertical and horizontal movement of the vehicle into account by adjusting the reversal point and the bank angle to satisfy range and terminal heading angle requirement.
Application Study of the Vehicle's Steering System with Mechanical Mechanics
Authors: Meng Ling Qin , Wang Zhi Wei
Published: December 2012

The design of the steering system is a very important part of the vehicle design, the steering system have a direct impact to the vehicle's handling and stability, the steering portability as well as the driver's work intensity and efficiency. The paper introduced the composition and characteristics of the vehicle's steering system. Analysis of the basic requirements and key technologies of the vehicle's steering. According to the applications and the advantages and disadvantages of the existing two-wheel steering system, advance a concept of four-wheel steering system, analysis of the structure of the four-wheel steering technology and the problems to be solved. In addition,studied the application situation of the power steering system in the vehicle steering mechanism from mechanical mechanics.
Dynamics and Trajectory Tracking of a Spherical Rolling Robot on an Inclined Plane
Authors: Yu Tao , Sun Han Xu , Jia Qing Xuan , Zhang Yan Heng , Zhao Wei
Published: December 2012

In this paper, we derive the dynamics of a spherical rolling robot, called BYQ-III, rolling without slipping on an inclined plane through the constrained Lagrange method. We present a state space realization of this constrained system, and develop a control algorithm for stabilizing the robot to track a desired trajectory on the inclined plane based on input-output feedback linearization. The validity of the proposed control scheme is then verified through simulation study.
Effect of Activated Carbon Materials’ Surface Texture Parameters on Separation Factor for Coal Mine Methane
Authors: Yang Xiong , Liu Ying Shu , Li Yong Ling
Published: December 2012

Nine types of active carbon materials’ adsorption isotherm of nitrogen at 77K were measured, and their surface texture parameters were calculated out. Then there adsorption isotherm of coal mine methane at 298K, 308K and 318K were measured experimentally. The equilibrium selectivity factor of methane to nitrogen was calculated out based on Langmuir equation. And the optimal adsorbent for coal mine methane separation is AC1 in these nine types of active carbon with separation factor of 4.6 at 298K. The experimental result indicated that the separation characteristic for coal mine methane does not only depend by its specific surface area, pore volume and it also depend by its micropore structure. The relationship between the surface texture parameters and separation factor at 298K could express by a multiple linear regression equation:α=3.20323-0.000728164S-3.73458V+8.16711V’ +0.02026dp(R2=0.933).
Effects of Different Carbon Sources on Performance of LiFePO4/C Composite Material
Authors: Yang Chao , Li Yong Mei , Liu Shan , Yao Yao Chun
Published: December 2012

Two kinds of carbon sources and their mixtures with different proportions were employed to prepare the LiFePO4/C composite material by high temperature solid state method. Precursor materials with different carbon sources were prepared by planetary ball-milling without dispersant. Results showed that the various precursors had different effect on the uniformity of the mixing and the crystallinity of the LiFePO4/C positive material. The mixed carbon sources had better effects on the performance of positive material. When the ratio of sucrose and citric acid was 1:3 (75% citric acid), the discharge capacity of LiFePO4/C composite material was 144.1 mAh/g at the discharge rate of 0.2C. Its high-rate performance was also better.
Analysis of Voltage Losses in High Temperature Proton Exchange Membrane Fuel Cells with Properties of Membrane Materials and Fluent Software
Authors: Yang Xiao Le , Yin Yan , Jia Bin , Du Qing
Published: December 2012

The mass and charge transport significantly affect the performance of fuel cells. A numerical model of high temperature proton exchange membrane fuel cells is developed. Ohmic losses and activation losses of both anode and cathode are analyzed at different design and operating condition. The polarization curve predicted by the model is in a reasonable agreement with published experimental data. The results of the model indicate that increasing the phosphoric acid doping level or operating temperature is helpful to decrease ohmic losses. The operating temperature has negligible impact on activation losses. Increasing the operating pressure can decrease activation losses.
Surface Morphology Studies on PBI Membrane Materials of High Temperature for Proton Exchange Membrane Fuel Cells
Authors: Zhai Zhen Yu , Shen Ying Gang , Jia Bin , Yin Yan
Published: December 2012

Compare with the conventional proton exchange membrane fuel cells (PEMFCs), high temperature proton exchange membrane fuel cells (HT-PEMFCs) have more advantages such as higher CO tolerance of catalyst, easier water management and higher catalyst activity. As the core component of the HT-PEMFC, proton exchange membrane should have excellent flexibility , thermal stability and high proton conductivity at high operation temperature and anhydrous environments. By atomic force microscope (AFM) technology, the surface topography image and lateral force image of the untreated and treated polybenzimidazole (PBI) membrane are investigated.