Advanced Materials Research Vols. 476-478

Abstract: The mechanical response and damage mechanism of a 3D multi-structured knitted composite under quasi-tensile loadings are investigated based on experimental results. The multi-structured knitted composite consists of two knitted fabrics with weft double-faced interlock knitted fabric as core material and biaxial warp-knitted fabric as surface layer in the above-mentioned composite system, respectively. The tensile stress against strain curve is obtained to analyze the mechanical behavior. Furthermore, the failure mechanisms of 3D multi-structured knitted composite are discussed from the experimental observations by the initiation and propagation of damaged zone in knitted composites.

Abstract: 2.5D woven composites has been used broadly. But its failure reason and process has not been researched clearly. To describe whole the tensile process in weft direction exactly, Based on the yield criteria ,yield criteria and elastic mould reduced rule are consummated to analyze the process of yield process; Meantime, Hoffman failure criteria is used to analyze the broken process and the corresponding elastic mould reduced rules is given. FEA method is adopted to simulate and analyze the whole tensile process of 2.5D woven composites in weft load at last. To verify the failure criteria and the corresponding elastic mould reduced rule, weft –tensile tests of six kind of 2.5D composites have been done. Results of contrast show that failure criteria and the corresponding elastic mould reduced rule is very suit for 2.5D woven composites. The whole failure progress for a sample with hole are simulated at the end of this paper.

Abstract: With the increased use of carbon fiber reinforced polymer (CFRP) composites in civil infrastructure, understanding the fire structural performance of these materials is an important safety issue. In this paper, the effect of temperature on the tensile strength of carbon fibers and carbon/epoxy composite sheets was experimentally determined from 20°C to 500°C. Meanwhile, in order to better understand the strength degradation of carbon fiber-polymer composites at elevated and high temperatures, the tension tests were also performed for pure epoxy resin and CFRP sheets by means of 10°C off-axis at the range of 20-80°C, respectively. The experimental results reveal that the strength decrease of carbon composites under tensile loading at elevated and high temperatures is dependent on both thermal softening of the epoxy polymer matrix and thermally-activated weakening of the fibers. The reduction in strength of carbon fiber is attributed to oxidation of the high strength grapheme layer at the near-surface fiber region.

Abstract: As the market's own flaws and disorderly competition in accounting and auditing intermediary market economic needs, resulting in value against the integrity of the CPA, there is a serious credibility crisis, has become China's CPA profession is facing the survival and development of key issues. From an economic perspective, the article use the game theory research tools in the commission of certified public accountants audit the integrity of the value, then presents a lack of good faith conclusion.

Abstract: Spinning effluents (SE) from dry-spun acrylic fiber producing are hard to biodegrade for dimethyl formamide (DMF) and nitriles contained. Integrated membrane filtrations including micro-filtration (MF), ultra-filtration (UF) and nano-filtration (NF) were adopted to separate the pollutants in SE. Experiment showed that MF has weak capacity for the removal of organic pollutants, while NF and UF contributed to 49.49% and 31.51% to the initial COD removal rates of SE.

Abstract: With the introduction of Be-doped AlxGa1-xAs template, self-assembled In0.79Mn0.21As quantum dots samples were prepared on semi-insulating (001) GaAs substrates by molecular beam epitaxy. High quantum dots density was confirmed by the atomic force microscopy. The ferromagnetism of the samples was revealed by superconducting quantum interference device magnetometer analysis at 10K, and the Curie temperatures ranging from 292 to 314K were able to be regulated by adjusting Al content and Be dopant in Be-doped AlxGa1-xAs templates, implying the feasible application of spintronic devices.

Abstract: Thermodynamic analysis on destabilizing effect of zirconia products caused by aluminum is carried on by using material Gibbs free energy function, and then the experimental verification was tested by scanning electron microscope (SEM). The results show that: 1) aluminum reacts with calcium oxide, the stabilizer of zirconia, forming some sheet-like calcium hexaluminate. It results in the stabilizer loss and the volume destabilization of zirconia. 2) Aluminum reacts with magnesium oxide, the stabilizer of zirconia, forming some octahedral magnesia-alumina spinel. It results in the stabilizer loss and the volume destabilization of zirconia. 3) The destabilizing effect of zirconia caused by aluminum can be defined three layers, which are original layer, transition layer and reaction layer.

Abstract: Based on the VC++ development environment and Solid works software, a system about cam design and motion simulation is developed. First, build up the input interface for input parameters, output values and curve display such as velocity and acceleration according to the input parameters. Then the data is imported into the Solid works software as input data for motion simulation. Therefore, the velocity and acceleration are simulated. The results show that the cam design system can be run and give help for cam design application.

Abstract: Polyaniline(PANI)/montmorillonite(MMT)composites were prepared by situ emulsion polymerization of aniline at 0 °C in the presence of MMT in aqueous solution with ammonium persulfate (APS) and dodecylbenzene sulfonic acid (DBSA) as oxidant and surfactant (acid dopant), respectively. Infrared spectra revealed the shift of N-B-N stretching vibration band, suggesting the presence of interfacial interactions between PANI chains and clay layers. X-ray diffraction showed an increase in the interlayer spacing from 1.26 nm for MMT to 1.468nm for PANI/MMT10%, signifying PANI was intercalated into the MMT galleries and the expansion is in agreement with the intercalation of single chains with extended chain conformation. Thermal gravimetric analysis suggested that the introduction of MMT clay resulted in improvement of thermal stability of the composites. It was found that when the MMT content reached a certain limit (30%), the PANI/MMT showed higher conductivity than pristine PANI .

Abstract: Silver nanoparticles have been extensively used as the anti-microbial agent in medicine. The present study addressed their antifungal potential against phytopathogenic fungi. Ag-SiO2 core–shell nanoparticles (Ag-SiO2 NPs) with an average size of 118.2 ± 4.6 nm were successfully prepared. The released Ag+ slowly through the outer porous SiO2 coating layer from the silver cores was detected in potato dextrose medium, reaching a peak value of 0.016 ppm around day 4. Ag-SiO2 NPs have displayed excellent antifungal effects against tested phytopathogenic fungi even at a low concentration of 0.5 ppm. The antifungal activity of these Ag-SiO2 NPs is not just the effect of dissolved Ag+ released from the nanoparticles. Our results suggested that the induced reactive oxygen species (ROS) by Ag-SiO2 NPs were involved in the effect of growth inhibition on tested fungi.