Applied Mechanics and Materials Vol. 377

Abstract: In this study the relation between output voltages of PZT piezoelectric ceramic body with applied impact mechanical energy are studies. The output voltages of PZT piezoelectric ceramic body are increased with the increasing of the applied mechanical energy. Under the same impact mechanical energy, the output voltages of the PZT piezoelectric ceramic body are depending on both the dimensional size and properties of the samples. The PZT piezoelectric ceramic body with greater (t/D²) can produce a higher output voltage. With the same piezoelectric ceramic body size, under the same impact mechanical energy, the output voltage of soft type piezoelectric ceramic body is higher than that of hard type piezoelectric ceramic body, which is because the g₃₃ value of soft type piezoelectric ceramic body is higher than that of hard type piezoelectric ceramic body.

Abstract: Superparamagnetic Fe₃O₄ nanoparticle with single phase has been synthesized successfully by a co-precipitation process. On the other hand, the effect of additive anhydrous ethanol in synthesis procedure was investigated for the magnetic properties of nanoparticles in this paper. The structure properties of synthetic Fe₃O₄ particle were measured through XRD, FT-IR and TG-DSC devices. The characteristic peaks of Fe₃O₄ have been observed to testify Fe₃O₄ with single phase. The particle size and shape were observed by SEM and TEM measurements. The addition of anhydrous ethanol could enhance the dispersion of Fe₃O₄ nanoparticles and restrain the agglomeration of nanoparticles. Therefore, the average particle size was about 18.2 nm, smaller than that of Fe₃O₄ particles prepared without anhydrous ethanol of 24.3 nm. Correspondingly, the saturation magnetization (Ms) of Fe₃O₄ prepared with and without anhydrous ethanol was determined to be 53.28 emu/g and 65.28 emu/g, respectively, lower than bulk magnetite particles of 90 emu/g. That is because, synthetic Fe₃O₄ with smaller particle size obtains the higher surface curvature, which could enhance the disordered crystal orientation on the particle surface, so the saturation magnetization was decreased.

Abstract: Effect of Co-doping on gas sensing, electrophysical and structural properties of the SnO₂ films deposited by spray pyrolysis has been studied. It is found that the influence of Co-doping on parameters of the SnO₂-based gas sensors depends on the concentration of doping additives and could be accompanied by either improvement of sensor parameters at low levels of doping (C_Co< 2-4 %) or degradation of the gas sensor operation characteristics while the concentration of additives exceeds 2-4%. An explanation of observed effects is given.

Abstract: By the solvothermal synthesis the TiO₂ nanocrystals with different shapes were obtained. It was found that the morphology of TiO₂ nanoparticles determines the type of solvent and their crystallinity, and the size depends on the temperature and time of synthesis. The conditions are defined, under which the anatase nanocrystals are formed in the form of spherical particles with a diameter of 10-15 nm, cubic particles with a size of 50-70 nm and edges of nanowires with a diameter of 50-100 nm and a length of more than 100 microns.

Abstract: Wood-plastic composites (WPC) were prepared by compression molding process using high density polyethylene and wood fiber as the main raw materials. The influence of nanozinc oxide, nanosilver antimicrobial powder and rosin amid treatment on WPC was investigated respectively by testing the mass loss, flexural strength, color change, surface tension, as well as surface images of the composites before and after the corrosion test. The results indicate that nanozinc oxide has little antimicrobial effect on WPC. While nanosilver antimicrobial powder and rosin amid both have effects on the anti-corrosion properties of WPC. It is also suggested that the WPC with the mass fraction of 6% rosin amid is the most antimicrobial, and its mass loss and flexural strength only decrease by 0.0788% and 2.24% respectively. These cost-efficient WPC can be practical to industrial application.

Abstract: Calcium sulfate hemihydrate has been used for many years as a biomaterial. However, too fast a degradation rate and lack of bioactivity have limited its application in orthopaedic field. Herein, α-Calcium sulfate hemihydrate is used as the raw material to prepare spherical particles calcium sulfate with stir method. Microstructures, degradation, and bioactivity of the materials were characterized by XRD, FT-IR and SEM. The effects of solutions of sodium silicate (Na₂SiO₃) on the structure and properties of the materials were analyzed. The results indicate that both the interface structure and the surface crystal binding state of the spherical particles calcium sulfate are changed by the solutions. The bioactivity was significantly improved by the solutions of Na₂SiO₃. With increasing the concentration of solutions in the materials, the degradation rate of the materials is decreased. Si-O network membrane which contains a large amount of Si-OH was formed on the surface of calcium sulfate. Therefore, the degradation rate was decreased and the bioactivity was significantly improved.

Abstract: This paper provides new data on the visible light catalytic degradation of aqueous solution of diesel fuel on the calcium bismuthate - bismuth oxide catalyst compositions. It also investigated the toxicity of the catalyst composition and the products of the catalytic decomposition of diesel fuel.

Abstract: Stimulating cell proliferation is a challenge in the field of silk fibroin-based biomaterials. In this study, silk fibroin/hyaluronic acid blend films were prepared by a casting method using carbodiimide as a cross-linking agent. Carbodiimide induced silk fibroin to form Silk I crystal structure which was not affected by the presence of hyaluronic acid. The films showed high water resistance. In vitro, the performance of these films was assessed by seeding L929 cells. The results indicated that the silk fibroin/hyaluronic acid blend films with the blend ratio of 80/20 and 60/40 promoted cell proliferation compared with the pure silk fibroin or hyaluronic acid film. These results suggest that silk fibroin/hyaluronic acid blend films are water stable and cytocompatible materials which are expected to be useful in biomedical applications.

Abstract: The influence of discharge gas pressure on the structural properties of SnO₂ thin films deposited by reactive magnetron sputtering at room temperature was investigated by X-ray diffraction, field emission scanning electron microscopy, and by the measurement of film density and physical adsorption isotherms. As the pressure increased, the grain size increased and the crystallite size decreased; simultaneously, a void structure developed, and the film became porous, indicating a lower film density. According to the results of physical adsorption isotherms, the effective surface area and the porosity increased with increasing discharge gas pressure.

Abstract: To dehydrate the isopropanol (IPA) by the pervaporation separation process at 25°C, the polysulfonamide thin-film composite (TFC) membranes were prepared via the interfacial polymerization of diamines including 1,3-diaminopropane (DAPE), 1,3-cyclohexanediamine (CHDA) and m-phenylenediamine (MPDA) with 1,3-benzenedisulfonyl dichloride (BDSC) on the surface of modified asymmetric polyacrylonitrile (mPAN) membrane. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectrometry, atomic force microscope (AFM) and water contact angle (WCA) measurements were applied to analyze chemical structure, surface roughness and hydrophilicity of the polymerized layer of composite membrane. In the dehydration of aqueous isopropanol solutions, the DAPE-BDSC/mPAN membrane had the higher permeation flux and the similar water concentration in permeate compared with the CHDA-BDSC/mPAN and MPDA-BDSC/mPAN membranes. The pervaporation performance of the composite membrane was affected by the chemical structure of the polysulfonamide polymer.