The biomimetic method of achieving dense platelike grain growth of the high temperature superconducting ceramic YBa2Cu3O7 (YBCO) has been studied. By using various organic matrices (dextran and chitosan) having differ...
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Pyrite cinder is the solid waste generated from the industrial manufacture of sulfuric acid.A new type of cementitious material was prepared by using pyrite cinder as raw materials instead of natural raw materials at ...
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Pyrite cinder is the solid waste generated from the industrial manufacture of sulfuric acid.A new type of cementitious material was prepared by using pyrite cinder as raw materials instead of natural raw materials at 1280℃for 30min in the lab,the main mineral phases were CS(45-55%) and CAxFl-x(45-55%).The mechanical properties, mineral compositions and microstructure of the cement clinker were investigated using X-ray powder diffraction(XRD),scanning electron microscope(SEM),etc..The result showed that the content of CAxF1-x have an significantly influence on the compressive strength,which increases with CAxF1-x content *** compressive strength, setting time and heat evolution of the cement were affected by the content of natural gypsum(NG).We founded that the compressive strength of the cement gradually decreases with NG content increasing at 3 days and increases at 28days and 56days, the optimal NG content is 20%.The final setting time of the cement without NG is less than 30 min while the setting time of the cement containing 20%NG is prolonged The effect of NG content on heat evolution is distinct at different hydration *** main mineral phases of cements with different NG content was unhydrated CS and AFt. Originality In this work,we studied a new type of cement mainly consisting of two mineral phases, *** ferroaluminates and belite utilizing an industrial by-product pyrite cinder. The new cement have high relative content of CAxF1-x(45-55%) and C2S(45-55%) compared with traditional cement due to a large amount of silica,alumina,and ferrous oxide in pyrite *** firing temperature is lower compared with traditional cement and so far no one has done a similar scientific research.
The microstructures and mechanical properties of novel multiphase Nb-based composites from Nb–Ti–C–B system have been investigated. The microstructures were characterized using scanning electron microscopy, transmi...
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The microstructures and mechanical properties of novel multiphase Nb-based composites from Nb–Ti–C–B system have been investigated. The microstructures were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The composites contain Nb solid solution, (Nb,Ti)B boride and (Nb,Ti)C carbide phases. The hybrid (Nb,Ti)B and (Nb,Ti)C together with Nb solid solution form the network microstructure. The composites exhibit high hardness and strength while maintaining desirable fracture toughness at room temperature. Boride and carbide phases effectively improve the strength and hardness of the composites, while Nb solid solution toughens the composites. Higher boron contents increase the hardness and strength, but decrease the toughness.
Multi-wall carbon nanotubes (MWCNTs) were oxidized by soaking in mixed acids. Their microstructure and composition were characterized using transmission electron microscopy, atomic force microscopy, Raman spectroscopy...
Multi-wall carbon nanotubes (MWCNTs) were oxidized by soaking in mixed acids. Their microstructure and composition were characterized using transmission electron microscopy, atomic force microscopy, Raman spectroscopy and infrared spectroscopy. The influence of soaking time on microstructure and dispersibility of the cut MWCNTs in aqueous solution was investigated. Results show that the MWCNTs were oxidized at defect sites by the mixed acids and converted from highly tangled ropes into short, open-ended nanotubes with lengths of 200–1500 nm. The isoelectric point was reduced from 4.5 to 3.5 due to hydroxyl and carboxyl groups on the surface and the open ends of the cut MWCNTs. The aggregation experiments and UV–vis absorbance spectra revealed that the cut MWCNTs can be best dispersed in an aqueous solution containing 0.1 wt.% of sodium dodecyl-benzenesulfonate when sonicated at a pH value of 2 for 40 min. [New Carbon Materials 2014, 29(2): 109–117]
In this paper nanotube TiO2 coating as an interlayer was produced on Ti substrate and the performances of the Ti/nanotube TiO2/Sb-SnO2 electrodes were investigated. It is shown that the microstructure of the nanotubes...
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ISBN:
(纸本)9783037857076
In this paper nanotube TiO2 coating as an interlayer was produced on Ti substrate and the performances of the Ti/nanotube TiO2/Sb-SnO2 electrodes were investigated. It is shown that the microstructure of the nanotubes changes with the anodic oxidation voltage and time, and the introduction of the nanotube TiO2 in the electrodes gives rise to both the oxygen evolution potential and the accelerated life of the electrodes.
The biomimetic method of achieving dense platelike grain growth of the high temperature superconducting ceramic YBaCuO（YBCO） has been studied. By using various organic matrices（dextran and chitosan） having differe...
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The biomimetic method of achieving dense platelike grain growth of the high temperature superconducting ceramic YBaCuO（YBCO） has been studied. By using various organic matrices（dextran and chitosan） having different molecular structures, the final size and arrangement of the platelike YBCO grains exhibit significant differences, possible reasons for which are discussed. The different organic matrices used also indirectly affect the superconducting properties of the YBCO formed. By elucidating the role of the organic matrix in the biomimetic synthesis process in this way, the whole process could be controlled more precisely, leading to structural and electrical properties of the final product more desireable for specific applications.
Endowing both solvent independency and excellent thermal bistability, the benzobis(thiadiazole)‐bridged diarylethene system provides an efficient approach to realize extremely high photocyclization quantum yields ( ...
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Endowing both solvent independency and excellent thermal bistability, the benzobis(thiadiazole)‐bridged diarylethene system provides an efficient approach to realize extremely high photocyclization quantum yields ( Φ o‐c , up to 90.6 %) by both separating completely pure anti‐parallel conformer and suppressing intramolecular charge transfer (ICT).
Polyacrylonitrile-based carbon fiber bundles, with two sides fixed, were heated in a graphitization furnace with temperature profiles similar to those used in the preparation of carbon/carbon composites. The microstru...
Polyacrylonitrile-based carbon fiber bundles, with two sides fixed, were heated in a graphitization furnace with temperature profiles similar to those used in the preparation of carbon/carbon composites. The microstructure of the microvoids formed was characterized by small-angle X-ray scattering and high resolution transmission electron microscopy (HR-TEM). Results showed that the average radius of gyration of the microvoids decreases, and their length, width, cross-sectional area and volume fraction decrease followed by a slight increase with increasing temperature, with the minima found at around 2300 °C. The HR-TEM images showed that the microvoids were formed by stacking defects of the carbon layers. The ordering of the amorphous carbon layers accounted for the initial decrease of size and volume fraction of the voids with increasing temperature, while the growth and ordering of the layers at high temperatures gave rise to increases in their size and volume fraction. [New Carbon Materials 2013, 29(1): 41–46]
The structure and magnetic properties of the nanocrystalline Sm5Co19-xHfx(x= 0,0.2,0.3)bulk alloys were *** results show that the Sm5Co19-xHfx alloys have single phase with the Ce5Co19-type crystal *** microstructure ...
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The structure and magnetic properties of the nanocrystalline Sm5Co19-xHfx(x= 0,0.2,0.3)bulk alloys were *** results show that the Sm5Co19-xHfx alloys have single phase with the Ce5Co19-type crystal *** microstructure analysis indicates that the average grain size of the alloys is about 20 nm and the grain size distribution is *** intrinsic coercivities were obtained for the Sm5Co19-xHfx *** increasing the Hf content from x=0 to 0.3,the coercivity increases from 36.63 kOe to 40.13 *** Rietveld structure refinement shows that Hf prefers to occupy the 6c site in the lattice,which results in an enhancement of the anisotropy field of the Sm5Co19 compound [1,2] and an increase of the *** present study provides guidance for the composition design of the Sm5Co19-type permanent magnets.
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