Applied Mechanics and Materials Vols. 271-272

Abstract: Generally, hydrogel compounds derived from either natural or synthetic chemical suffer from lack of mechanical strength. So high strength poly(acrylic acid) -chitosan-silica (PAA-Ch-Si) hydrogels were prepared by UV light or γ-ray irradiation method for scaffold material application in this paper. The absorption peaks from FTIR show the evidence for the successful grafting of PAA- Ch-Si hydrogel material through radiation co-polymerization. The mechanical property analysis indicate that the maximum compressive strength of this hydrogel was significantly increased to ~42 MPa when PAA incorporated with both chitosan and nano-silica. And from the test results, we can observe that these nanocomposites are fitted to appling for biomedical materials.

Abstract: Al-induced crystallization (AIC) method was used for obtaining polycrystalline silicon (poly-Si) film on glass substrate. The films with glass/a-Si:H/Al structure were fabricated by Plasma Enhanced Chemical Vapor Deposition (PECVD) and magnetic sputtering. Then the samples were sent to perform annealing treatments during the different temperatures and time. The experimental results demonstrate that a highly crystallized poly-Si sample can be achieved by annealing at 480°C for 2h. The crystalline fraction (Xc) of the sample is about 99.1% and the Full Width at Half Maximum (FWHM) is 4.89cm^-1. The average grain size of this sample is about 250nm. The energy dispersive spectroscopy (EDS) measurement confirms that the residual Al in the film is very little.

Abstract: Based on the analysis of the conductive mechanism of the conductive rubber used in robot tactile, the paper discussed the influence of the type, particle size and amount of the conductive filler on the dielectric properties of the force-sensitive conductive silicone rubber.Experimental results showed that, for the same mass fraction of the filler material, the particle of bigger size would bring the resistance to decrease more quickly, on the contrary, the smaller one made the the resistance decline.Under the same pressure, with the increase of the amount of graphite filled, the resistivity of the samples would decrease. The resistance of the silicone rubber was changed by the alloy powder added, and the relationship between the tendency of resistance change and the amount of alloy addition was not a single linear, however it significantly increased the range of pressure sensitive of the conductive silicon rubber, and the dielectric properties were improved at the same time.

Abstract: ZnO film and Cu2S/ZnO bilays on the glass substrate were fabricated by RF magnetron sputtering. We carried out the experiments by adjusting the thickness of Cu2S on ZnO layer. The performance of Cu2S/ZnO on the transparency, conduction and photocatalysis were investigated. The photocatalytic experiments showed a good photocatalytic activity for photodegradation of methyl orange.

Abstract: Material transfer characteristics and surface morphology of contact material reflects their electrical erosion performance. In this paper, by using a JF04C contact material testing machine, the characteristics of electrical erosion of PtIr contact materials are acquired under low voltage, resistive load and small current. By means of an electronic balance and SEM, the material transfer values of the PtIr contact materials and the characteristics of contact material surface profile are obtained and analyzed. The results show that PtIr alloy contact materials mainly transfer from cathode to anode and its breaking arcs are metallic phase.

Abstract: The fire protective clothing is essential protective equipment in fire-fighting operations for the firefighters, which can effectively reduce the damage of high temperature and radiation to the firefighters in the fire. In the actual fire-fighting and rescue, mastering the specific thermal protective effect of the fire protective clothing is necessary in order to accurately grasp the security extinguishing distance. Firstly, this paper presents an overview of the development and performance requirements of the fire-retardant insulation materials for the fire protective clothing, and performance evaluation standards are also introduced. And then take a large crude oil reserves depot for example, and set the pool fire scene inside the tank, which builds the risk analysis model of pool fire. Not considering the impact of the wind speed, the flame height of a single tank in the pool fire is 76.2m, and the total thermal radiation flux is 1.4 × 106kw. The threshold is set at the standard that the firemen directly affected by the thermal radiation feels the pain above 20s, and the safe di^{Superscript text}stance of extinguishing the fire for the firefighters is 167m without the protective clothing; the safe distance of extinguishing the fire for the firefighters is 78.4m under the protection of the clothing.

Abstract: In project practice, Anchor ability of coupled steel bars concrete will higher than cold rolling belt rib steel bars. So, more economical steel bars and cement contents. Through comparative trial about on concretes component of coupled steels bars and cold rolling belt rib steel bars in this article. Summarizes that anchor ability of Low-alloy coupled steels are depending transverse steel, well, steel bars and concretes has the better joint work ability.

Abstract: In this paper, the Fe3O4 magnetic nanometer particle was prepared by co-precipitation method. At the same time, the samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the surface active agent (PEG4000) can be good for the dispersion performance of Fe3O4 magnetic nanometer particle; and the temperature of 80°C is the appropriate drying temperature to prepare the Fe3O4 magnetic nanometer particle.

Abstract: The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The Ultrasonic test is done before and after impacting. Under different drop hammer impact times, polypropylene fiber mortar specimens' damage degree was evaluate based on ultrasonic velocity. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar. The ultrasonic velocity of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of wave speed decline.

Abstract: The linear shear rheological behaviors of polyethylene/montmorillonite (PE/MMT) nanocomposites were investigated by a rheometer. The storage moduli (G′) and loss moduli (G″) of PE/MMT nanocomposites increase obviously with the silicate loading only 0.1 wt%, this is ascribed to a strong interficial adhension. The presence of MMT leads to pseudo-solid-like behaviors and the molecular chain of PE/MMT melts confined. For all samples, the dependence of G′ and G″ on ω shows nonterminal behaviors. The terminal slope decreases as the silicate loading increased from 0.1 % to 0.8 wt%. However, the terminal slope of PE/MMT nanocomposites increases as the silicate loading increased from 0.8 % to 1.2 wt% . This may be attributed to the aggregation of a small amount of MMT.