Applied Mechanics and Materials Vols. 513-517

Abstract: The mesoporous polycarbonate-silica nanocomposite materials were synthesized through the modified sol-gel approach under acidic condition. The specific surface area, pore diameter and pore volume of polycarbonate-silica could be controlled by changing the acidity of the synthesis system. The polycarbonate-silica possess an irregular block morphology according to the scanning electron microscopy observations. With decreasing the pH value of the synthesis system, the specific surface area and pore diameter of polycarbonate-silica were raised but the pore volume was reduced. The maximum specific surface area of polycarbonate-silica was 701.71m²/g which presented by the results of Nitrogen adsorptiondesorption isotherms.

Abstract: The amphiphilic chitosan oligosaccharides graft copolymer (PHCSO-g-PCL) was synthesized via ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) through an amino group protection route using phthaloyl chitosan oligosaccharide (PHCSO) as intermediate. The graft reaction was carried out in Pyridine at 120 °C with a chitosan oligosaccharide (CSO) initiator and a tin 2-ethylhexanoate (Sn (Oct)₂) catalyst. The amphiphilic PHCSO-g-PCL nanoparticles were prepared through the self-assembled in DMF organic solvents. PHCSO-PCL copolymer was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The physicochemical properties of the hydrophobized PHCSO-g-PCL nanoparticles were investigated by using dynamic light scattering (DLS). The results of DLS showed that the hydrodynamic diameters and particle size distribution with various concentrations of PHCSO-g-PCL nanoparticles were from 69.82 nm to 195.9 nm with a narrow polydispersity factor of 0.212 to 0.172.

Abstract: Steel-concrete castellated composite beams are a new form, also widely used in bridges and buildings. But the research for the vibration characteristics of the composite beams is less. In this paper, by using the principle of the finite element, it mainly analyzes the influence of some related elements, such as the steel beam web part of the opening location, the size, the location and so on, on composite beam vibration frequency to lay the foundation of further study on the dynamic characteristics of the castellated composite beam.

Abstract: 3D porous scaffolds were produced by a combined salt leaching-phase inverse technique. Results showed that micorpores and macropores distributed in the produced scaffolds with high porosity (more than 75%). The interconnectivity can be influenced by the use of methanol and water as a nonsolvent to induce liquidliquid phase separation. The addition of the nonsolvent and NaCl had influence on compression property of the scaffolds.

Abstract: Polyacrylonitrile precursor fiber as the as-spun fiber of carbon fiber plays a vital role in carbon fiber performances. In order to optimize the production process and the fiber performances of polyacrylonitrile precursor fiber, a production parameters optimization approach is proposed to find the relationship between the initial input and the final output of this fiber production and help to determine the production parameters according to the fiber performances required. Because fiber production is a complex industry process with a lot of parameters working together and them all have effect on the final performances, so this optimization is a multi-objective optimization which is based on particle swarm optimization formulas and production data. This approach can maintain the diversity of solutions, improve the accuracy of production parameters determining and provide a optimization of polyacrylonitrile precursor fiber.

Abstract: According to test exploration and research, the authors developed a multiaxial compression testing machine and water injection pressure device. Using the device, the authors carried out a multiaxial compression testing of transparent rock-like material successfully under water pressure condition. It has important meanings to the study on the engineering characteristic of fractured rock under pressurized water conditions.

Abstract: In this paper I will introduce a new kind of powder concrete which I call it UHPC.UHPC is a kind of high performance concrete. Now the cost and the condition of ordinary powder concrete is too high. It is unfavorable to the popularization and application of powder concrete. This article mainly is to use gravel that have particle size range between 3 ~ 5 mm and particle size range between 1 ~ 3 mm and particle size range between 0.21 ~ 0.42 mm river sand .the aggregate will through the close packing to match. Gelling materials mainly use three kinds of cement. They are ordinary Portland cement 52.5, sulfur-aluminum cement, and superfine cement grinding. The appropriate ratio of gelled material will determine by the experiment. Poly carboxylic acid additive and defoaming agent will be used to configure the reactive powder concrete. Main purpose is to configure economy powder concrete in Regular maintenance condition.

Abstract: The Youngs modulus of multilayered nanothin films is an important property. This paper focused to investigate the Youngs Modulus of Multilayered Ni/Cu Multilayered nanoThin Films under different condition by Molecular Dynamics Simulation. The NVT ensemble and COMPASS potential function were employed in the simulation. The multilayered nanothin film contained the Ni and Cu thin films in sequence. From simulation results, it is found that the Youngs modulus of Cu/Ni multilayered nanothin film is different at different lattice orientations, temperatures and strain rate. After experiments, it can be found that the Youngs modulus of multilayered nanothin film in the plane (100) is highest. As thickness of the thin film and system temperature rises, Youngs modulus of multilayered nanothin film is reduced instead. And, the strain rate increases, the Youngs modulus of Cu/Ni multilayered nanothin film will also increase.

Abstract: A copolymer was prepared by grafted a novel phenolic resin to hydrolyzed polyacrylonitrile as fluid-loss-control additive. The novel phenolic resin used Bisphenol A residues as raw materials. Results of Fourier transform infrared spectroscopy (FTIR) showed that the two polymers were grafted into together. It was found that the copolymer gave a well performance under high temperature and high pressure and saline pollution.

Abstract: The effects of tungsten contents (80-88wt.%) and different Ni:Cu ratio (7:3-3:7 by weight) on microstructure and dynamic mechanical properties of W-Ni-Cu alloys were investigated. Results show that at the same sintering conditions, with tungsten content increasing from 80 wt % to 88 wt %, tungsten grains increase slightly. Spherical and more uniform tungsten grains distribute in matrix phase in 85W alloys with Ni:Cu ratio of 1:1 than that of 3:7 and 7:3. The results also show that the dynamic yield strength of W-Ni-Cu alloys goes up with tungsten content increasing, but keep similar deformation capability. With strain rate increasing in the range of 2600-4200s^-1, 85W displays strain rate softening effect. Adiabatic shear bands are formed at strain rate over 3200s^-1.