bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Dissipation of Martensite Reorientation in NiMnGa Single Crystals under Biaxial Compression
Authors: Chen Xue , He Yong Jun , Moumni Ziad
Published: March 2013

Experiments of biaxial compression were conducted to study the energy dissipation (stress-hysteresis) of martensite reorientation in NiMnGa single crystals. From the experiments, the observed stress-hysteresis consists of two parts ― the material intrinsic friction due to martensite reorientation, and the external friction between the loading clampers and the sample surfaces. It is found that the former one is independent of the 2D stress state while the latter one strongly depends on the 2D stress levels. Both kinds of friction are important and need to be considered in real applications.
Modeling of Smart Material Properties of Heusler Alloys
Authors: Breczko Teodor , Barkaline Viatcheslav , Douhaya Yana
Published: March 2013

The results of the computer simulations of certain electronic properties of the austenite phase of Ni-Mn-Ga alloy are presents. Cluster approach was used and both self-consistent and density functional methods were exploited.
Martensitic Transformation in Spark Plasma Sintered Compacts of Ni-Mn-Ga Powders Prepared by Spark Erosion Method in Cryogenic Liquids
Authors: Ochin Patrick , Gilchuk Andrii V. , Monastyrsky Gennady E. , Koval Yuri , Shcherba Anatolij A. , Zaharchenko Sergij N.
Published: March 2013

Ni-Mn-Ga-based magnetic shape memory materials were elaborated by spark plasma sintering method. Micron sized particles were prepared by spark-erosion method in liquid argon and liquid nitrogen from preliminary melted magnetic shape memory master alloys Ni-28.5Mn-22.5G at.%. Powders were annealed in H2 gas atmosphere before sintering. Depending on the cryogenic liquids the morphology of particles alternated between spherical solid and hollow balls. The conditions of spark eroded powder elaboration strongly effect on the morphology, martensitic behavior, and structure of sintered samples. In particularly, martensite has 5M structure in bulk material; 14M and non-modulated martensites were found in annealed powders and sintered compacts correspondingly.
Calorimetric Study of Avalanche Criticality in the Martensitic Phase Transition of Cu67.64Zn16.71Al15.65
Authors: Gallardo M. Carmen , Romero F. Javier , Manchado Julia , Martín Olalla José María , Planes Antoni , Vives Eduard , Salje Ekhard K.H. , Romero Ricardo , Stipcich Marcelo
Published: March 2013

The first-order diffusionless structural phase transition in Cu67.64Zn16.71Al15.65 is characterized by jerky propagation of phase front related to the appearance of avalanches. In this work we describe a full analysis of this avalanche behaviour using calorimetric heat-flux measurements and the results are compared with acoustic emission (AE) measurements.
Martensitic Transformation in Mn-Ni-Sn Alloys
Authors: Coll R. , Bonastre J. , Saurina J. , Suñol J.J. , Escoda L. , Hernando B.
Published: March 2013

In this work, we analyze two Mn50Ni50-xSnx alloys with Sn content i.e., x = 5 and 7.5 respectively. These alloys are produced as ribbon-shape by melt spinning. Their structural transformation is checked by calorimetry. Martensitic transformation temperatures of these alloys strongly depend on the composition. From X-ray diffraction analysis, the 14M monoclinic phase is the main phase in both alloys, but in the alloy Sn5 appears a minor tetragonal phase too.
Ab Initio Study of Magnetic Properties and Phase Diagram of Ni-Mn-Ga Heusler Alloys
Authors: Zagrebin Mikhail A. , Sokolovskiy Vladimir V. , Buchelnikov Vasiliy D.
Published: March 2013

In this work the magnetic properties (exchange parameters, magnetic moment of non-stoichiometric Ni–Mn–Ga Heusler alloys with structural disorder by the help of ab initio calculations have been performed. Theoretical composition dependences of the total magnetic moment are in qualitative agreement in qualitative agreement with experimental data. Calculations of exchange parameters show that interactions between the Mn atoms in regular positions and Mn atoms in Ni and Ga positions are antiferromagnetic.
Microstructure and Mechanical Properties of the SPD-Processed TiNi Alloys
Authors: Gunderov Dmitriy , Lukyanov Alexander , Prokofiev Egor , Churakova Anna , Pushin V.G. , Prokoshkin Sergey , Stolyarov Vladimir , Valiev Ruslan
Published: March 2013

The article represents results of influence of different severe plastic deformation (SPD) techniques on TiNi alloys. It is demonstrated that strength and shape memory effect (SME) of TiNi can be significantly enhanced due to formation of ultrafine-grained (UFG) and nanocrystalline (NC) structures by SPD. Influence of equal channel angular pressing (ECAP), high pressure torsion (HPT), multi-step SPD deformations (ECAP plus cold rolling) on structure, mechanical and functional properties of TiNi alloys is considered. There are represented first results of influence of equal channel angular pressure-Conform (ECAP-C) on TiNi alloys, which is a perspective technology for industrial fabrication of UFG metals and alloys.
Shape Memory Properties of Ultrafine-Grained Austenitic Stainless Steel
Authors: Käfer Karine Andrea , Bernardi Heide Heloise , Naito Leonardo Kenji Fudo , Lima Nelson B. , Otubo Jorge
Published: March 2013

In this work the effect of grain refinement on the shape memory properties of a Fe-Mn-Si-Cr-Ni-Co-Ti alloy was evaluated using compression tests. In order to refine the microstructure, the samples were heavily deformed by equal channel angular extrusion (ECAE) and then annealed at different temperatures ranging from 450°C to 1050°C. These treatments resulted in the formation of intermetallic precipitates and strengthening of austenitic matrix. The results of compression testes show that the higher degrees of shape recovery (56 % for 4% strain) were achieved by the samples with smaller grain size (12 µm).
Structure and Properties of NiTi Shape Memory Alloys after Severe Plastic Deformation
Authors: Stróż Danuta , Palka Jakub , Lekston Zdzisław , Dercz Grzegorz
Published: March 2013

The results presented here concern two NiTi alloys (near-equiatomic NiTi and Ni-rich alloy) subjected to plastic deformation by compression combined with reversion oscillating torsion. The maximal strain obtained was εc = 6.20. Finally the alloys were annealed at the temperature range 300 – 500°C for 1 hour. The structure of the as-prepared alloys was studied with the use of temperature X-ray diffraction and TEM observations. Also the DSC and bend and free recovery ASTM tests were carried out. It was found that the structure consists of a mixture of highly deformed B2 parent phase and B19’ martensite. The TEM studies revealed some amorphous areas in the most strained region of the samples. Annealing at lower temperatures caused formation of nanocrystalline structure that grew to the microcrystalline and finally well-defined polygonized structure in annealed at 500°C specimens. Multi-stage transformation was observed in the annealed at lower temperatures samples.
Formation of Nanostructure Surface Layers from Materials with Shape Memory Effect TiNiCu in Conditions
Authors: Rusinov Peter Olegovich , Blednova Zhesfina
Published: March 2013

Results of an experimental research on formation of surface layers from a material with shape memory effect (SME) three-componental structure on the basis of TiNiCu combined method including mechanical activation and a plasma dusting in vacuum are presented. It is shown, that the plasma dusting in vacuum of three-componental system TiNiCu allows to receive surface layers in nanostructure condition practically of any thickness. The structure, chemical and phase structure of blankets TiNiCu provide display SME. The average size of grain of coverings TiNiCu fluctuates within 20-200 nanometers. It is experimentally shown, that superficial modifying TiNiCu raises durability of a steel 45 at multicyclic loading on ~30-45 %, and wear resistance in 2,5 3 times.
Structure and Properties of TiNi Alloy Subjected to Severe Plastic Deformation and Subsequent Annealing
Authors: Belyaev Sergey , Drozdova Maria , Frolova Natalia , Pilyugin V.P. , Resnina Natalia , Slesarenko Viacheslav , Zeldovich Vitali
Published: March 2013

Processes, occurring on annealing of TiNi alloy, processed by high pressure torsion (HPT), were the focus of this research. Some peaks of heat release were found on heating the deformed samples up to 550 °C. If the initial structure of the alloy was amorphous (after 3.5 turns of HPT), then structural relaxation, crystallization and grain growth occurred on heating. When alloys had a crystalline structure (after rotation by 15 and 90 degrees), recovery, recrystallization and further grain growth took place on heating. It was observed that the TiNi alloy, subjected to 3.5 turns of HPT and subsequent heating up to 550 °C, underwent unusual kinetics of martensitic transformations. The austenite B2 phase transformed to the martensite B19' phase in two ways: B2→R→B19' and B2→ B19'.
Amorphization of Titanium Nickelide by means of Shear under Pressure and Crystallization at the Subsequent Heating
Authors: Frolova Natalya , Zel'dovich Vitaly , Pilyugin V.P. , Gundyrev Vyacheslav , Patselov Alexander
Published: March 2013

Transmission electron microscopy and X-ray diffraction were used to study structural changes in the Ti-50.5 at. % Ni alloy upon severe plastic deformation by shear under pressure and subsequent heating. An increase in the degree of deformation leads sequentially to a martensite transformation, twinning of martensite crystals, formation of reorientation bands, development of rotational modes of deformation, formation of a nanocrystalline structure, and finally amorphization. A scheme of the formation of amorphous structure of the alloy during deformation is suggested based on the observed structural changes. It has been found that a reverse martensitic transformation might be one of mechanisms of plastic deformation of the alloy. Therefore, as the degree of deformation increases, first forward and subsequently reverse martensitic transformations can occur. The formation of an amorphous structure starts as the degree of deformation reaches 4.2 (one revolution of Bridgman anvils); at a degree of deformation of 6.8 (5 revolutions of the anvils), the process is virtually completed. The crystallization of the amorphous alloy upon heating starts even at 200°C. However, upon heating up to 300°C (for 0.5-h holdings), the kinetics of crystallization is slow. After annealing at 350°C, the complete crystallization with the formation of a nanocrystalline structure with a grain size of 20-70 nm takes place
Influence of Sintering Process on the Mechanical Properties of Dental Zirconia Ceramics
Authors: Park W.U. , Zhao J.M. , Hwang Kyu Hong , Kim T.S. , Yu C.H. , Lee J.K.
Published: March 2013

Densification and mechanical properties of dental zirconia ceramics were evaluated by different sintering methods. Y-TZP zirconia block was used in this study. Sintering were performed in electric heating furnace and microwave sintering furnace, and then experimented and analyzed on a change in densification according to the sintering time, a change in densification according to thickness, flexural strength and micro-structure of zirconia specimens. Microwave sintering was very effective in considerable mechanical properties such as flexural strength and bulk density was drastically increased than conventional electric heating method. It is also shown that microwave sintering was faster and more economical than common method to be present in qualities which equal or exceed. It will be important to seek the accurate sintering condition of dental zirconia by microwave sintering method and the continuous research is necessary for the study of relationship between sintering methods and mechanical properties.
Role of Phase Stress in Variations of Cell Behavior on NiTi
Authors: Danilov Anatoly , Muhonen Virpi , Tuukkanen Juha , Jämsä Timo
Published: March 2013

Phase stresses that arise from volume mismatch between austenite and martensite crystal lattices were studied at different stages of direct and reverse martensitic transformations in NiTi alloy for medical application. The absolute stress values of tensile and compressive stresses that operated in austenite and martensite respectively were shown to be Gaussian functions of phase composition: they increased from zero in the initial single-phase state, achieved maximum at the equilibrium between the initial and new phases and decreased to zero in the ultimate phase. Phase stress distribution on the surface of simulated two-phase sample and related distinctions in osteoblast-like cells’ behavior were analyzed. Negative effect of compressive stress on cell viability and probable mechanism of cell apoptosis are discussed. Recommendations concerning the choice of permissible size discrepancy between organ and implant as well as NiTi alloy composition to avoid/minimize negative consequences of two-phase state after implant installation are suggested.
Investigation of Electrochemical Behavior of Novel Superelastic Biomedical Alloys in Simulated Physiological Media
Authors: Zhukova Yulia S. , Konopatsky Anton S. , Pustov Yury
Published: March 2013

This paper focuses on study of the kinetics and the mechanism of passive film formation on novel superelastic biomedical Ti-22Nb-6Ta and Ti-21.8Nb-6Zr (at.%) alloys in simulated physiological solutions using XPS and electrochemical techniques in comparison with commercially pure titanium and Nitinol. In vitro biocompatibility study of Ti-22Nb-6Ta alloy was carried out as well. Ti-22Nb-6Ta alloy manifests a strong trend to protective passive film formation during the first stage of oxidation in simulated physiological solutions. It is shown that Ti-22Nb-6Ta and Ti-21.8Nb-6Zr electrochemical characteristics are comparable to those of titanium and Nitinol, and the alloy can be recommended for use in implantology.
Improvement of Actuating Properties of a SMA Coil Spring by Change in Coil Orientation
Authors: Jee Kwang Koo , Han J.H. , Jang W.Y.
Published: March 2013

The present authors have invented a new method of changing coil orientation of a coil spring. The major merit of coil orientation change for SMA are reduction of space and control of two way shape memory effect. For instance, when a coil is heated above Af temperature with a load, the coil contracts. There is unrecovered strain which is attributed to elastic deformation by the load. The elastic strain can be eliminated by changing coil orientation. By removing elastic strain, the necessary space can be reduced. Besides generation and control of two way shape memory effect is presented using the reverse of coil orientation.
Nano- and Microcrystal Investigations of Precipitates, Interfaces and Strain Fields in Ni-Ti-Nb by Various TEM Techniques
Authors: Schryvers Dominique , Shi Hui , Martinez Gerardo T. , Van Aert Sandra , Frenzel Jan , Van Humbeeck Jan
Published: March 2013

In the present contribution several advanced electron microscopy techniques are employed in order to describe chemical and structural features of the nano- and microstructure of a Ni45.5Ti45.5Nb9 alloy. A line-up of Nb-rich nano-precipitates is found in the Ni-Ti-rich austenite of as-cast material. Concentration changes of the matrix after annealing are correlated with changes in the transformation temperatures. The formation of rows and plates of larger Nb-rich precipitates and particles is described. The interaction of a twinned martensite plate with a Nb-rich nano-precipitate is discussed and the substitution of Nb atoms on the Ti-sublattice in the matrix is confirmed.
Low Temperature Transformations in β-Metastable Ti 5553 Titanium Alloy
Authors: Settefrati A. , Aeby-Gautier E. , Appolaire B. , Dehmas M. , Geandier G. , Khelifati G.
Published: March 2013

Precipitation decomposition in β metastable phase in TI 5553 alloy were characterized by electrical resistivity and high energy X-ray diffraction for two thermal paths, isothermal transformation at 325°C after direct quenching, or cooling to room temperature and further ageing at 325°C. Both treatments led to different transformation sequences with formation of ω and/or α''. Mean cell parameters of β and α'' were characterized all along the transformation. Results suggest a transformation with poor solute partitioning and building of large stresses in each phase.
Multi-Wire Electrical Discharge Slicing for Silicon Carbide
Authors: Itokazu Atsushi , Hashimoto Takashi , Fukushima Kazuhiko , Yuzawa Takashi , Sato Tatsushi
Published: March 2013

In this paper, we propose a new wafer slicing method for silicon carbide(SiC). SiC is well-known as a difficult-to-cut material, and a conventional slicing via multi-wire saw becomes more difficult with increasing ingot size. To solve this problem, the multi-wire electrical discharge slicing (EDS) method is applied to 100 mm-square SiC polycrystalline block. We successfully obtained the average thickness of 385 μm for nine sliced plates by ten-wires EDS. The thickness variation was measured to be less than 11.2 μm. This is the first demonstration of ten-wires EDS for 100 mm-square SiC material.
Boundary Condition Effect on Thermoelectric Coefficients
Authors: Wang Chun Lei , Su Wen Bin , Peng Hua , Zhu Yuan Hu , Liu Jian , Li Ji Chao
Published: March 2013

nfluence of physical boundary conditions on the thermoelectric transportation coefficients has been analyzed starting form Onsager equations. Four boundary conditions have been considered: electric short, i.e, the chemical potential difference is zero; electric open, or electric current free; isothermal, i.e., no temperature difference; adiabatic, or heat flux free. Four kinds of thermoelectric equations have been derived with different boundary conditions. It was found that the influence of boundary cannot be ignored when figure-of-merit is near and larger than 1.0. This results could be useful in designing thermoelectric device with high performance thermoelectric materials.
Preparation and Microstructure Control of One-Dimension Core-Shell Heterostructure of Te/Bi, Te/Bi2Te3 by Microwave Assisted Chemical Synthesis
Authors: Hong Xiao Jie , Fan Xian , Wu Zhao Yang , Wang Guo Qiang , Zhu Cheng Yi , Li Guang Qiang , Hou Yan Hui
Published: March 2013

Microstructure engineering of thermoelectric materials can resolve the conflicts of electrical and thermal transports. Especially, one-dimensional structure can obviously improve the thermoelectric figure of merit because of its crystal anisotropy and strong quantum confinement effect. In this paper, the Te nanowires, one-dimensional core-shell heterostructure of Te/Bi and Te/Bi2Te3 were controlled synthesized by microwave assisted chemical synthesis. The effect of PVP concentration and reductant dropping rate on the microstructure of the Te nanowires were investigated. The experimental results showed that with increasing the amount of PVP, the Te nanowires got less crystallinity and its surface become more rough due to its steric hindrance effect. With decreasing reductant dropping rate, the longer and thiner Te nanowires were obtained. Epitaxial growth can describe the relation of core Te and shell Bi (or Bi2Te3). It has been found that Bi shell uniformly surrounded around Te nanowires core, but Bi2Te3 sheets were perpendicular to the c-axis of Te nanowires. The different core-shell heterostructure structure can be obtained by adjusting reaction conditions and controlling diffusion kinetics of Te and Bi.
Study on the Influences of Foaming Gypsums Performance
Authors: Huang Bin , Zhang Yi , Li Dong Xu
Published: March 2013

Utilizing the chemical reaction principles H2O2 was catalyzed by MnO2, instead of being catalyzed by warm water. In the gypsum slurry, due to the chemical reaction of hydrogen peroxide a large number of bubbles were produced, and the material was self-foaming. The H2O2 foaming agent and the method of foaming affected the performance of the foaming gypsum, such as mechanical strength, apparent density, thermal conductivity, and the pore structure of foaming gypsum. The result showed that with adding H2O2, the apparent density and mechanical strength decreased; the different water/plaster weight ratio ranged from 0.65 to 0.75, affecting the foaming process. The thermal insulation property of FGD gypsum is related to the content of H2O2, the water/plaster weight ratio, and the pore structure of foaming gypsum.
Distributions and Species of MnOx Included in MnOx/TiO2 Catalysts for Denitration at Low Temperature
Authors: Fang De , He Feng , Xie Jun Lin , Hu Hua , Shi Zai Ying
Published: March 2013

MnOx/TiO2 catalysts are active and stable at low temperature, and it is appropriate for cement production to enforce NOx emissions. In this study, the denitration process was promoted by the transformation of a variety of MnOx forms in the SCR reaction. The efficiency and selectivity of catalysts depended on the form and dispersion degree of MnOx. By changing the precursors, calcination temperatures, synthesis methods and calcination atmospheres, a series of MnOx/TiO2 catalysts were prepared. The contents and distributions of Mn2+, Mn3+ and Mn4+ in catalysts were tested through the titration method. The titration results showed that the content of Mn4+ was the highest during the precursor was Mn (NO3)2, while the content of Mn2+ in the catalysts calcinated in nitrogen atmosphere was the highest. The mechanisms of different MnOx states in the catalytic process were discussed. It was found that a mixture of more MnOx with low valence state and less MnOx with high valence state were beneficial to the catalytic process.
The Change of Silica Tetrahedron in Cement-Silica Fume Blends Hydration
Authors: Wang Xiao Jun , Wang Xiao Yao , Zhu Hong Fei , Cong Xiao Ye
Published: March 2013

The change of silica tetrahedron in cement-silica fume blends hydration is critical for blended cement application. 29Si solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) investigations on the change of silica tetrahedron, which were Portland cement hydration, silica fume in simulated hydration and cement-silica fume blends hydration, were characterized and compared in this paper. The experimental results revealed that the amorphous silica tetrahedron structure in silica fume changed into Q1 and Q2 silica tetrahedrons, the same as silica-oxide structure of cohesive gel in the hydration of Portland cement. The coexistence of Q1 and Q2 silica tetrahedron in hydration product was beneficial to the strength increase of blend paste with silica fume. The amount of Q2 silica tetrahedron in cement-silica fume blends was higher than that in Portland cement. The pozzolanic reaction of silica fume accelerated the course of the silica tetrahedron in blended paste turning into the stable state of Q2 silica tetrahedron and existing principally in blended paste. That is reason that the physical properties of cement-silica fume blends are better than those of Portland cement.
Formation Mechanism of the Slice and Rod-Like Cerium Dioxide Precursor Particles
Authors: Chen Jian Qing , Chen Zhi Gang , Wei Yong
Published: March 2013

Ultra-fine cerium dioxide precursor particles was prepared with cerium (III) nitrate hexahydrate (Ce (NO3)36H2O) and urea (CO(NH2)2) at 85°C by homogenous precipitation method. Effects of reaction and ageing time on the morphology of the precursor particles were studied, the morphology of precursor particles was characterized by scan electronic microscope and the crystallinity of the precursors was studied by X-ray diffraction. The result showed that the mono-dispersed spherical particles turned into flower and bundle-like particles as reaction time increasing, the particles turned into slice and rod-like particles as the ageing time increasing, the transition process occurred in ageing process was later than that in the reaction process, the spherical particles were less crystallization and the slice and the rod-like particles were at a state of fine crystallization.
The Adsorptive Ability of TiO2-Pillared Montmorillonite for Lead (II) Cationic and its Leaching
Authors: Cheng Yuan , Xie Wei Miao , Zhang Xuan Hui , Chen Dan , Li Guo Hua
Published: March 2013

In this thesis, TiO2-pillared montmorillonite was prepared by a sol-gel method. The sample was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the crystal phase of the sample is composed of anatase and montmorillonite. The microstructure of the sample is still layered structure. Furthermore, the XRD results indicate that the interlayer distance of crystal plane (001) of the montmorillonite left-shift obviously. In other words, its interlayer distance increases obviously. The adsorptive ability of the sample was tested with industry wastewater, which containing Pb2+. The results indicate that the adsorptive rate of sample for lead () cationic is 99.9%. After analyzing with the interlayer space, it indicated that the increasing of the interlayer space is good for the adsorptive ability. And the adsorptive ability reached a maximum when the interlayer space was 1.339 nm. The TiO2-pillared montmorillonite absorbed Pb2+ saturatedly was impregnated into nitric acid solution to dissolve the lead cationic. The results show that the concentration of the nitric acid is higher, the leaching rate of the lead cationic is higher. And it reached a maximum when the concentration of the nitric acid is 2 mol/L after leaching for 20 min.Introduction
Preparation of Calcium Silicate Board by Fly-Ash Based Calcium Silicate Powder by Press Molding
Authors: Wang Shu Li , Qin Guo Tong , Wei Wei
Published: March 2013

Calcium silicate board has been prepared by press molding from fly-ash based calcium silicate powder with the pulp fiber as the reinforcing fibre. The micro-morphology and crystal structure of the obtained calcium silicate board were analyzed by SEM and XRD. The effects of cement,silica fume and molding pressure on the flexural strength and thermal conductivity of calcium silicate board were investigated. When the molding pressure is 10MPa, samples flexural strength, bulk density and thermal conductivity are 5MPa, 0.7g/cm3 and 0.12 W/m·K respectively. It was found that this kind of calcium silicate powder was complete hydrated and could not be further hydrated even in autoclave curing.
Oil Column Method for Magnetic Microspheres with Core-Shell Structure
Authors: Yu Lian Qing , Dong Kai Tuo , Zhi Qian Qian , Cai Ming Jiang
Published: March 2013

Spherical alumina catalysts have been widely used in fluidized bed and slurry-bed or catalyst carrier due to their excellent pore structure, large surface area, good physical strength and resistance to acids and stability. Magnetic microspheres of γ-Fe2O3 @ Al2O3 with core-shell structure were obtained by γ-Fe2O3 magnetic core coating with aluminum sol. After aging, drying and calcinations process, microspheres with certain hardness and magnetic properties can be obtained. During the preparation of core-shell structure microspheres, effect of both the content of aluminum sol, hexamethylenetetramine(HMT), magnetic core γ-Fe2O3 and process parameters of shaping time, aging temperature, calcination temperature on the properties of the spherical carrier was investigated. The optimum properties of microsphere carrier for hardness of 36.32 N/mm, specific surface area of 89.016 m2/g, pore volume of 0.874 cm3/g and average pore diameter 18.51 nm were synthesized, respectively.
Photosynthetic Inhibition on the Microalga Phaeodactylum tricornutum by the Dried Macroalga Gracilaria tenuistipitata
Authors: Ye Chang Peng , Zhang Meng Cheng , Yang Yu Feng
Published: March 2013

The effects of the dried macroalga, Gracilaria tenuistipitata (Rhodophyta), on photosynthesis of a highly stress-resistant microalga, Phaeodactylum tricornutum were studied. P. tricornutum was cultured with dried G. tenuistipitata under controlled laboratory conditions for three days. All oxygenic photosynthetic organisms tested so far exhibit a polyphasic rise of fluorescence transients during the first second of illumination. These phases are labeled as O, J, I, P. The chlorophyll a (Chl a) fluorescence transient O-J-I-P curve coupled with its specific parameters in P. tricornutum was established. The Chl a fluorescence transients were recorded in vivo at high time resolution and analyzed according to the JIP-test which can quantify photosystem II activity. A clear dose-and time-dependent relationships were observed between the dried biomass of G. tenuistipitata and its inhibitory effect on Pyramimonas sp. A decrease in the O-J-I-P curve expressed as Chl a fluorescence intensity along with its specific parameters were observed, which was also time-dependent. The main photosynthetic inhibitory targets of the macroalga on the microalga, according to the JIP-test, can be expressed as a decrease in the number of active reaction centers and the blocking of the electron transport chain. The results of the present study suggest that dried fragments of G. tenuistipitata effectively inhibit photosynthesis in P. tricornutum and could thus be potential candidates for use in the control and mitigation of harmful algal blooms.
Phytoremediation of Cadmium Contaminated Soils: Advances and Researching Prospects
Authors: Su Hui , Cai Zhang , Zhou Qi Xing
Published: March 2013

More and more attention has been paid to soil contamination by heavy metals in recent years. Heavy metal contamination includes heavy metal - heavy metal contamination, heavy metal - organic contamination, and heavy metal nutrient contamination. In particular, soil contamination by cadmium (Cd) is the most typical one. In terms of the current remediation technologies, phytoremediation of Cd contaminated soil remains popular due to its low cost, environmental aesthetics and in-situ effective treatment. Therefore, screening-out and identification of Cd hyperaccumulators becomes a hotspot in this researching domain. In order to further improve the efficiency of phytoremediation, we have developed a variety of joint remediation technologies. Based on these work at home and abroad, we summed up the studying progress in this field. Some main researching contents and directions of phytoremediation for Cd contaminated soils were also proposed.
LCA Method of MSC and Low-NOx Burner Technology in Cement Manufacturing
Authors: Li Chen , Cui Su Ping , Gong Xian Zheng , Meng Xian Ce , Wang Hong Tao
Published: March 2013

LCA method was used to model the life cycle of cement manufacturing with multi-stage combustion and low-NOx Burner technology applied as its low-NOx system. The life cycle is from the coal and raw materials transportation, through the coal and raw meal grinding, to the clinker incineration, and finally the flue gas including NOx to the air atmosphere. The functional unit is 1 tonne clinker. Data for cement produced in MSC and LNB technology is analyzed. The data is collected from the real clinker production situation and the measurement is taken in 12 hours continuously.
A Research on In Stiu Synthesis of Starch/Lactic Acid Graft Copolymer by One-Step
Authors: Hu Ying Mo , Wang Qing Ling , Bian Jing
Published: March 2013

The synthetic methods that starch graft copolymerized with lactic acid have been preliminary studied with catalysis of ordinary chemical reagents by one-step, and the structure of starch/lactic acid graft copolymer was characterized by IRH-NMRXRD and SEM et al. The experimental results show that sodium hydroxide (NaOH), zinc oxide (ZnO) and stannous chloride (SnCl2) so on can catalyze the graft copolymerization of starch with lactic acid successfully, it will provide a simple synthetic process to prepare starch/lactic acid graft copolymer.
Preparation and Photocatalytic Performance of α-SiW11Ti/PANI/TiO2 Nanocomposite
Authors: Ma Rong Hua , Deng Li Yang , Wang Dan Dan
Published: March 2013

An efficient α-SiW11Ti/PANI/TiO2 nanocomposite photocatalyst was prepared by a In-stiu polymerization method. (NH4)2S2O8 was used as an oxidant to form polyaniline-wrapped TiO2 particles and then by an electrostatic assembly of α-SiW11Ti. The α-SiW11Ti/PANI/TiO2 nanocomposite were characterized by UV-visible absorption spectrum (UV-Vis), Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity in degradation of malachite green on the α-SiW11Ti/PANI /TiO2 was carried out in an aqueous solution. The results show that the sensitizing effect of PANI can improve the light response of TiO2 and enhance the separation efficiency of electron and hole pairs, which in turn promotes the photocatalytic activity of the composites. This novel photocatalyst exhibits high photocatalytic activity to decompose malachite green under 30 W ultraviolet light irradiation. The malachite green was degraded by 97.53% after 90 min irradiation on the α-SiW11Ti/PANI/TiO2 nanocomposite, which was better than that of Degussa P25 (TiO2) and PANI/TiO2.
Preparation and Photocatalytic Activity of Yellow Titania
Authors: Li Lin , Xi Sheng Qi , Xing Yang Nan , Shang Fei Hu
Published: March 2013

Titania powder was prepared by a sol-gel method and heat-treatment (HT). The morphology and structure of the titania powder were characterized by X-ray diffraction (XRD), differential thermal analysis, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of powder was investigated using methyl orange as target compound. Colour changing of powder was due to colour centers form. Under visible light, yellow powder showed the better photocatalytic activity than P25 powder and its visible light response was expanded. Preparation of yellow powder lowered conventional calcinations temperature obviously.
The Fabrication of Large-Area Upgraded Metallurgical Grade Multi-Crystalline Silicon Solar Cells in a Production Line
Authors: Chen Teng , Zhao You Wen , Don Zhi Yuan , Wang Jun , Liu Tong , Xie Hui
Published: March 2013

Upgraded metallurgical grade (UMG) silicon has been researched both on the purification methods and its material properties for years, indicating that it is the most promising choice as low-cost feedstock for photovoltaics. In this work, UMG multi-crystalline silicon (mc-Si) prepared by cold crucible refining and electron beam melting was investigated. Solar cells based on such silicon wafers were fabricated in a 156 x 156 mm2 production line and their photovoltaic properties were characterized. Compared with the conventional mc-Si solar cells fabricated in the same commercial production line, the UMG mc-Si solar cells with two busbars presented higher average open circuit voltage (Voc) and average fill factor (FF), which were 628 mV and 78.6 % separately. Although the UMG mc-Si solar cells showed a lower shot-circuit current density (Jsc) of 32.7 A/cm2 in the average and an early reverse breakdown voltage at around 11 V which was due to higher impurities content. The average conversion efficiency of the UMG mc-Si solar cells reached 16.14 %, and the highest conversion efficiency was up to 16.31 %. In addition, the UMG mc-Si solar cells presented relatively low light induced degradation (LID) due to the material properties. Consequently, in consideration of low cost, our UMG mc-Si solar cells substantially met the requirements of commercial manufacturing and had a great potential application for photovoltaic industry.
Recent Developments of ZnO-Based P-Type Transparent Conductive Oxide Thin Films
Authors: Wang Ming , Diao Xun Gang , Guo Ting Ting , Wang Xuan
Published: March 2013

Nowadays, high performance p-type transparent conductive oxide (TCO) thin films have gained tremendous intersts, and the fact is that if p-type TCOs with high electrical conductivity and optical transmittance can be fabricated, transparent p-n junctions can be obtained and invisible electronics be realized, and hence the use area of TCOs will be highly broadened. A lot of work have been done on non-stoichiometric and doped versions of p-type TCOs in the last few years to improve the optical and electrical properties by various deposition techniques. ZnO-based thin films were thought to be the most promising candidate for p-type TCOs based on the fact that ZnO has advantages over the others, so in this paper the development of ZnO-based p-type TCOs has been discussed. Firstly, the reasons why p-type ZnO-based TCOs are difficult to synthesize were discussed, and then the general ways now used to produce p-type ZnO-based TCOs were summerized, including intrinsic p-type ZnO, doping of groupelements, codoping of and elements, doping of group elements, the origin of p-type conductivity and the feasibility of each way, and the state-of-the-art optical and electrical properties were presented. Finally, the specific shortcomings in producing high quality p-type TCOs were discussed. Based on the comparision, it is believed that the doping of groupelements in ZnO may be the most pronising way in realizing p-type TCO.
Fabrication and its Transient Optical Properties of Graphene Thin Films
Authors: Zhu Jia Yi , He Jun Hui
Published: March 2013

Graphene thin films were fabricated via layer-by-layer (LbL) assembly of oppositely charged reduced graphene oxides (RGOs) and benign post-treatment. RGOs dispersions and thin films were characterized by means of transmission electron microscopy, UV-visible absorption spectrophotometer, Raman spectroscopy, and four-point probe. It was found that graphene thin films exhibited a significant increase in electrical conductivity after post-treatment. In addition, post-treatment and film thickness showed an effect on transient optical properties of graphene thin films. The transmittance (800 nm, pulse) of (RGO-PDDA+/RGO-O-)30 film decreased after post-treatment, and the transmittance (800 nm, pulse) of post-treated films decreased with increasing the number of LbL assembled bilayers.
Microstructure Characterization of Si/C Multilayer Thin Films
Authors: Han Ting , Chang Geng Rong , Sun Yun Jin , Ma Fei , Xu Ke Wei
Published: March 2013

Si/C multilayer thin films were prepared by magnetron sputtering and post-annealing in N2 atmosphere at 1100 for 1h. X-ray diffraction (XRD), Raman scattering and high-resolution transmission electron microscopy (HRTEM) were applied to study the microstructures of the thin films. For the case of Si/C modulation ratio smaller than 1,interlayer diffusion is evident, which promotes the formation of α-SiC during thermal annealing. If the modulation ratio is larger than 1, the Si sublayers are partially crystallized, and the thicker the Si sublayers are, the crystallinity increases. To be excited, brick-shaped nc-Si is directly observed by HRTEM. The brick-shaped nc-Si appears to be more regular near the Si (100) substrate but with twin defects. The results are instructive in the application of solar cells.
Fabrication of TiO2 Nanotubes Array by Anodization for DSSC
Authors: Yan Hong Zhou , Yang Jun You , Feng Shuang Long , Liu Ming , Peng Jiang Ying , Zhang Jia Qi , Li Wei Xin
Published: March 2013

TiO2 nanotubes array was fabricated by anodization. Effect of reaction duration on the morphology of TiO2 nanotube arrays was studied detailedly. The structure and morphology of the prepared nanotubes array was characterized by X-ray diffraction and scanning electron microscopy, respectively. The fabricated TiO2 arrays were peeled off and adhered to FTO glass with adhesive (mixture of tetrabutyl titanate and polyethylene glycol), then they were sintered at 450 for photoanode of DSSC. The photovoltaic performance of the prepared sample as the DSSC anode was investigated. An open circuit voltage of 0.69V and a short circuit current density of 7.78mA/cm2 were obtained, and the fill factor and the convert efficiency were 0.517 and 2.78%, respectively.
Sintering Time Influences on Microstructure and Electrical Properties of Scandium Doped Zinc Oxide Varistor Ceramics
Authors: Zhang Cheng Hua , Jiang Bin , Zhang Ke , Jiao Lei , Yu Ren Hong , Xu Dong
Published: March 2013

Sc2O3-doped zinc oxide varistor ceramics were prepared by a solid reaction route. The microstructure and the electrical properties was analyzed by scanning electron microscope and X-ray diffraction. Sintering time influences on the microstructure and the electrical properties of Sc2O3-doped zinc oxide varistor ceramics are studied. The results show that the electrical properties of Sc2O3-doped zinc oxide varistor ceramics sintered at 1000 and sintered for 1 h was better: the voltage gradient was 653 V/mm; the leakage current was 0.18 μA and the nonlinear coefficient was 57.1.
The Influence of Bi Content on the Properties of Bismuth Ferrite Thin Films Fabricated by Magnetron Sputtering
Authors: Yan Hu Rui , Ding Nuo Fan , Wu Gang , Yang Ping Xiong , Chu Jun Hao , Deng Hong Mei
Published: March 2013

In the process of BiFeO3 film preparation by magnetron sputtering, Bi element is volatile, leading to the films which often appear impurity phases. Therefore, Both Bi excessive 5% (B1.05FO) and 8% (B1.08FO) BFO film in Si substrate were prepared by magnetron sputtering. X-Ray Diffraction (XRD) results showed that the BFO thin films fabricated in the Si substrate are perovskite structure, that the B1.08FO film appeared less impurity phases than B1.05FO film, and that stress due to substrate lattice mismatch caused the shift of XRD patterns. In Raman study, it was concluded that both B1.08FO film and B1.05FO film appeared ten Raman peaks in the range from 50cm-1 to 800cm-1, and that B1.08FO Raman peaks intensity was stronger in 137.1cm-1.168.5cm-1 and 215.3cm-1. Spectroscopic ellipsometry test showed that the refractive index and the extinction coefficient of B1.05FO film were 2.25 and 0.07 respectively in 600 nm with 2.67eV of energy gap; the refractive index and the extinction coefficient of B1.08FO film were 2.14 and 0.05 in 600 nm respectively with 2.71eV of energy gap. Atomic Force Microscope (AFM) was used to characterize the film surface morphology, finding that the B1.08FO film prepared in Si substrate was denser while grain size and surface roughness were smaller.
Ferroelectric and Magnetic Properties of Co Doping Bi6Fe2Ti3O18 Ceramics
Authors: Chen Chun Yan , Hou Song , Mao Xiang Yu , Chen Xiao Bing
Published: March 2013

In this paper, for the purpose of enhancement in the magnetic behavior, the five-layer Aurivillius phase structure Bi6Fe2-xCoxTi3O18 (BFCT-x, x = 0.0 ~ 2.0) ceramics were synthesized using the solid-state reaction method from a mixture of Bi2O3, Co2O3, Fe2O3, and TiO2 powders with different stoichiometric ratio. The microstructure, ferromagnetic and ferroelectric properties are investigated. The crystallographic structures of BFCT-x are determined to be the typical five-layer Aurivillius phase with a suggested structural transformation at heavy doping of Co ions. At room temperature, the remnant magnetization (2Mr) of BFCT-0.0, BFCT-0.6, BFCT-1.0 and BFCT-2.0 samples are 0.043 memu/g, 0.59 emu/g, 0.81 emu/g and 1.75 memu/g, respectively. The 2Mr, at first, gradually enhance and reach a greatest value of 0.81 emu/g at x = 1.0 then degrade again with the increasing of the ratio x. At room temperature, the samples have ferroelectricity, which the remnant polarization (2Pr) of the BFCT-0.0 , BFCT-0.6, BFCT-1.0 and BFCT-2.0 samples are 2.8 μC/cm2, 8.0 μC/cm2, 3.0 μC/cm2 and 7.2 μC/cm2 respectively. The 2Pr first increases, then decreases and increases again with Co doping. When x = 0.6, the 2Pr reaches a maximum value of 8.0 μC/cm2.
Micro-Displacement Positioning of Giant Magnetostrictive Actuator
Authors: Liu Lin Lin , Zhang Tian Li , Zhang Heng , Jiang Cheng Bao
Published: March 2013

Giant magnetostrictive materials have a broad potential application in aviation and aerospace field owing to its good properties. The actuators made of the materials show excellent performance which makes them a good choice for precision positioning. This paper presents a micro-displacement positioning system of the giant magnetostrictive actuator (GMA). The structure of the system and its control method are described. In order to achieve the steady micro-positioning characteristics, the adjustment process of the system based on the control algorithm of Programmable Multi-axis Controller (PMAC) was researched. The response time of the GMA was less than 1 ms which was shown in the step response curve. Relatively large displacement (5~20 µm) positioning and micro-displacement (0.9~3 µm) positioning were achieved with the average positioning systematical errors of less than 0.5 µm.
AC Losses of YBCO Coated Conductor with Ferromagnetic Substrate in DC Field
Authors: Zhang Guo Min , Xu Zhen Ling , Yu Hui , Li Jin Cheng
Published: March 2013

As YBCO coated conductors are usually prepared on nickel or nickel alloy substrates, additional ferromagnetic losses are generated in the substrates when the conductors are exposed to AC magnetic fields or carrying alternative currents in practical application. In this work, AC transport loss factors of YBCO tapes with Ni-W alloy substrates were studied in DC magnetic fields. The influence of ferromagnetic substrate on AC loss and the repressive effect of DC background magnetic field on ferromagnetic loss in the substrate were presented and analyzed. The results showed that the AC transport loss factor of YBCO tape with Ni-W substrate decreased gradually with the increasing background field, and the minimum value of AC loss factor appeared as the field reach to about 18 mT and 45 mT for parallel and perpendicular applied field respectively. Based on the analysis, the method to reduce AC transport current loss in coated conductor with nickel alloy substrate is proposed.
Numerical Analysis of Levitation Forces Dynamic Behavior in the HTS-Magnet Levitation System
Authors: Zhang Wen Feng , Zhang Guo Min , Xia Dong , Qiu Qing Quan , Yu Zhi Qiang , Hu Lei
Published: March 2013

t is important to simulate the levitation force and its relaxation with time for the designers in the process of designing a HTS (high temperature superconductor)-magnet levitation bearing. In this paper, FEM (finite element method) based on HTSs critical-state model using H formulation was introduced. In the zero field condition, the process of magnetization of a cylindrical HTS bulk was simulated. The result showed that, current would be induced when HTS bulk was put in the external magnetic field, and the induced current tried to prevent the change of the magnetic field in the HTS bulk. When the external field disappeared, HTS bulk trapped some of the field and the bulk was magnetized. HTS-magnet levitation models were built in both the axisymmetric field and the plane field. Forces and their relaxations with time were calculated. In the HTS-magnet levitation system, force faded with time and faded slower as time went on. The force was bigger when the HTS bulk was put closer to the magnet and relaxed a little more.
Preparation of EuBCO Epitaxial and Textured Films by F-Free Polymer-Assisted Chemical Solution Deposition Method
Authors: Zhang Xin , Cheng Cui Hua , Wang Wen Tao , Zhang Yong , Zhao Yong
Published: March 2013

Epitaxial and textured EuBa2Cu3O7-x(EuBCO) superconductive films were prepared via a F-free polymer-assisted chemical solution deposition (PACSD) method on LaAlO3 (LAO) single crystal substrate in nitrogen atmosphere. Because of the fluorine-free metal organic system, no harmful gas was produced during processing by the PA-CSD method. The film morphorlogy, phase composition, texture and the superconducting critical temperature (Tc) of EuBCO films were investigated by x-ray diffraction (XRD),φ-scan, ω-scan rocking curves, an environmental scanning electron microscope (ESEM) and four-probe method. The Jc value of the EuBCO film in self-field at 77K was measured by using Jc-scan Leipzig system. The results shoed that a denser microstructure and better biaxial texture EuBCO film after a high temperature treatment with a superconducting critical temperature (Tc) of 91K was obtained . The critical current density (Jc) reached 2.4MA/cm2 at 77K in the self-field.