Abstract: In this paper, we use electromagnetic simulation software HFSS to investigate the distribution of electromagnetic field of microwave sintering cavity, and establish a simulation model for the TE103 single mode cavity. We then obtain the optimal condition for the distribution of electromagnetic field by capturing the contour of distribution of electrical field of cavity through simulation. Our research shows that electromagnetic simulation software HFSS can use color to effectively demonstrate the intensity distribution of electromagnetic field of internal space and various cross-sections within the microwave sintering cavity, which provides a novel method for improving and applying new ways to compute and predict the key features of field distribution. The simulation results by HFSS can guide the practical microwave sintering techniques as well as the design and improvement of the sintering cavity.
Abstract: Electrochemical impedance spectrum (EIS) and potentiodynamic polarization curve were applied to invest the corrosive behavior of Fe3Al/ZrO2 composites with different components in marine microbial medium. The results indicated that the existence of microbiology negatively moved the open circle potential. When the composites contained 30% (wt %) ZrO2, the passive film on electrodes surface was the thickest one, even after 25 days the material was still protected. When the content of ZrO2 was 90%, Fe3Al was in the least content, after 25 days the passive film has disappeared, but the material was still not eroded because of the high hardness and corrosion-resistant properties of ZrO2. When the content of ZrO2 was 80%, the passive film was partly damaged, which could lead to more serious local corrosion.
Abstract: We found that monodisperse polymeric particles with diameters in the range of a few hundred nanometers can be prepared by suspension polymerization with water as its dispersing medium. The ratio between monomer and water was selected to be 10 and polymerization conducted at 70oC. Azobisisobutyronitrile was employed as an initiator and a polymer with strong hydrophilic end groups as a stabilizer. Particle diameter was found to vary between 100 and 200 nm depending on reaction conditions. An increase in monomer concentration contributes to an increase in particle diameter and deviation from monodispersity. The weight average molecular weight of polystyrene beads was found to be dependent on the reaction temperature and initiator concentration. Glass transition was determined to be between 100 and 105oC.
Abstract: Crystal structures and shape memory properties of Ti-rich Ti52Ni23Cu25 (at.%) ribbon annealed at 450°C for 10 min and 1 h were investigated by X-ray diffraction and dynamic mechanical analyzer. As-spun ribbon was full amorphous and its crystalline peak temperature is 455.4°C. The annealed ribbon is crystallized with strong preferential (110)-B2 orientation. It shows a well-defined shape memory effect and the transformation hysteresis for the annealed ribbon under an external load in the range of 3-9 N is about 38.5°C. With annealing time increasing from 10 min to 1 h, the maximum of transformation strain under the external stress decreases from 1.93% to 1.7%. The temperature dependence of the external stress increases from 0.3 N/°C to 0.43 N/°C. The residual plastic strain is up to about 0.4% at a load of 9 N.
Abstract: The poly(acrylate-acryloyloxyethyl trimethyl ammonium chloride)/clay nanocomposite hydrogels (poly(AAc-DAc)/clay NC gels) with different clay contents were prepared by using clay as a cross-linker. The hydrogel exhibited good electroresponsive property and excellent mechanical property. The hydrogels initially bent toward the cathode side followed by anode side under an electric field. Concentrations of NaCl solution, voltage of electric field and clay content of the hydrogels have significant effects on the electroresponsive property of the hydrogels. Clay exhibited two opposite effects on the electroresponsive property of NC gels.
Abstract: The electrical resistivity and positive temperature coefficient (PTC) behavior of carbon black (CB)-filled high density polyethylene (HDPE) /ethylene-vinyl acetate copolymer (EVA) composites were investigated. At any particular CB content, the composite with the HDPE/EVA weight ratio 9/1 showed the lowest resistivity compared to other composites under investigation. The resistivity was decreased after the addition of small amount of EVA in HDPE with a particular CB loading. This is due to the improvement in dispersion of CB in HDPE in presence of small amount of EVA. However, the resistivity was again increased after the addition of higher amount of EVA due to the formation of an insulation polymer shield by EVA around CB particles. The nature and intensity of PTC was dependent on the HDPE/EVA ratio. With the increase in EVA content, PTC was shifted at a lower temperature. The highest PTC intensity was observed for the composite with HDPE/EVA ratio 8/2.
Abstract: Nanocrystalline zeolite β was synthesized by hydrothermal treatment, and the effect of aluminium source, SiO2/Al2O3 ratio, sodion, crystallization temperature etc. on particle size and morphology was studied. Under the optimum condition, zeolite β with the particle size about 100nm was successfully synthesized. The samples were characterized by XRD and TEM techniques, and the key factors influencing the particle size and morphology were revealed.
Abstract: TiN thin films were deposited by D.C reactive magnetron sputtering on glass and metal substrate. The relations between the technical conditions and the properties of the thin films are studied, According to control the intensity of gas pressure by changing the flux of Ar and N2, the structure of TiN films could be control. By changing the target power、N2 flux and substrate temperature, the relations between the technical conditions and the structure of TiN thin films were analyzed so as to produce the TiN thin films of excellent decorations, good corrosion resistance and high micro-hardness.
Abstract: A theoretical procedure was developed with the aim of obtaining a rapid and accurate estimation of the degree of crystallization in glasses obtained from fly ash by measuring the dielectric constants. Compositions were prepared by melting the mixture of fly ashes, nucleators, fusing agents and clearing agents at 1500°C. Dielectric constant measurements were carried out by means of universal bridge. The results were compared with the degree of crystallization as evaluated by the method of density and showed a good agreement.
Abstract: In this work, ZnO nanorods have been successfully synthesized by employing ZnCl2, NaOH as the starting materials by using different surfactants (including CTAB, SDS and SDBS), without using template supporting and structure-directing solvent at a low temperature ( 60 up to 90 °C ). X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to analyze the crystal structure and surface morphology. XRD pattern analysis showed that the ZnO clusters are single hexagonal phase of wurtzite structure with no impurity of others. Also, TEM images revealed that the size of a single ZnO nanorod is between 20 nm and 40 nm in diameter and between 200 nm and 2 μm in length. The structures, growth mechanism and the PL spectra properties of ZnO microcrystals are investigated.