Advanced Materials Research Vols. 482-484

Abstract: Taking into account the condition that dry friction may occur when Si3N4 and SiC are self-made into friction pair, experiments are carried out to contrast the friction and wear properties under the condition of dry friction. In this experiment SiC friction pair presents better friction and wear properties, whose ultimate bearing capacity is better than Si3N4.

Abstract: On-center handling performance for high speed vehicle is becoming more and more concerned. Road feel is the most indexes to evaluate the on-center handling performance. Steering system is the key part of the whole vehicle to affect the performance, which include much nonlinearity: steer ratio, dry friction and stiffness etc. In this paper, steering system model is set up by ADAMS, and embed into the whole vehicle model to study the effects of these nonlinearities on on-center handling performance.

Abstract: Silicon oxycarbide（SiCO）thin films is a kind of glassy compound materials, which possess many potential excellent properties such as thermal stability, wide energy band, high refractive index and high hardness, and have many potential applications in space. The preparation processes of SiCO thin films by RF magnetron sputtering with different substrate temperature, working pressure and sputtering power were studied. And various surface analysis methods were used to characterize the optical properties of SiCO thin films. The dependence of the properties on the process parameters was also studied. The tested properties of SiCO thin films deposited on K9 glass indicated that lower substrate temperature and sputtering power, higher working pressure could get SiCO thin films with better light penetration and the refractive index of SiCO thin films had a large varying region with the change of the process parameters. With different substrate temperature, working pressure or sputtering power, the maximum refractive index at 633nm（wavelength） are 2.20051, 2.12072 and 1.98959, respectively, and the minimum ones are 1.89426, 1.83176 and 1.8052, respective.

Abstract: A semi-active vibration system via magnetorheological (MR) isolators can contribute to enhance isolation performance. In this study, a vertical vibration model of subway rail via MR isolators was proposed. The adjustable damping and stiffness characteristics of isolator were also analyzed. Based on a floating slab track (FST) isolation model, a variable domain fuzzy control system was proposed to decrease the vertical vibration force. The results simulated in MATLAB indicate that compared with passive isolators, FST system via MR isolators decease vertical vibration force transmissibility ratio to 40% at low frequency (15Hz) and to 31% at medium frequency (30Hz).

Abstract: A new anti-swelling agent was synthesized by polymerizing epichlorohydrin and dimethyl amine polymer. The swelling inhibition properties were investigated over clay and shale. It was found that the clay inhibition of swelling properties was greatly enhanced compared with common inorganic salts. However, to shale, the swelling properties did not inhibited efficiently by using prepared polymers. Furthermore, the influence of cross linking of polyammonium to the swelling ability of prepared polymer has been also carried out by using triethylenetetramine cross linking agent. In the case of shale, the swelling inhibit properties was improved after cross link, while opposite swelling effect was observed over clay.

Abstract: Aotugenous volume deformation is one of the influence factors of stress field of concrete structure. Generally, the influence of temperature on autogenous volume strain is not considered in calculation. In fact, the difference of internal and surface temperature of concrete structure can lead to different hydration reaction and different autogeneous volume deformation. In order to find out the effect of temperature difference on aotogenous volume deformation and stress field of concrete structure, a model is established and a corresponding example is given. The result shows that it is necessary to take temperature effect into consideration while calculate autogenous volume deformation in stress field simulation of concrete structure.

Abstract: The chitosan-based blend films were prepared from chitosan, soybean trypsin inhibitor (TI) extract and glycerol (Gly) solutions, the properties of which were investigated, including mechanical property, water vapor transmission, transmittance, solubility, and the microstructure. Then, the antifungal activity against A. flavus by the blend films had been investigated. The resistance to A. flavus infection was partially due to the ability of TI to inhibit α-amylase activity, thereby limiting the availability of hydrolyzed reducing sugar for fungal growth. And the facts that the germination and growth of A. flavus were strongly inhibited by chitosan-TI-Gly film indicated the blend films might be useful as potential biocontrol packaging against A. flavus during the peanuts storage.

Abstract: The presented paper describes the creation of a computational model of highly porous materials, and a stress-strain analysis is performed. The computational model is created using micro-CT by the finite element method in the ANSYS 12.0 software. The micro-CT slices are converted into a 3D model using image processing. The local equivalent stress (HMH criterion) and struts deformation are analyzed. Commercially available ceramic foam, 85%Al2O3-14%SiO2- 1%MgO, was used in the experiment part of the paper.

Abstract: The anti-permeability of concrete is one of important indexes of the durability of concrete. The experiment on anti-permeability of cellulose fiber concrete and hybrid fiber concrete were made. And the rule of the anti-permeability of concrete with the different fiber types and mix amount of fiber was researched. The factors of influencing the anti-permeability of concrete were analyzed. The experimental results indicate that the anti-permeability of concrete is improved because of the cellulose fiber, and the permeability coefficient of concrete decrease with the increasing of content of fiber. Even the content of fiber is 0.9kg/m³, the anti-permeability of cellulose fiber concrete is obvious improved, while the steel fiber has less reinforcement effect.

Abstract: The silicate based low frequency sound absorption composite material was prepared with powdery polymethacrylimide (PMI) foam as filler. The effects of the amounts of PMI and pore-forming agent, and water-cement ratio on sound absorption properties of composite material were researched. Sound absorption coefficient was characterized by standing wave tube, and micro structure of composite material was analyzed by scanning electron microscope. The results show that: when the amounts of PMI and pore-forming agent are 2.5wt% and 0.04wt%, respectively, and water cement ratio is 0.55, the average value of the absorption coefficient on the sound （≤1000Hz）can up to 0.35. Resonating sound absorption structure formed by micro pore of the silicate and thin wall cavity of PMI in composite materials is beneficial to high efficiency absorption to low frequency sound.