Abstract: The effect of the aspect ratio of micro sphere lens arrays on the optical properties of diffuser including transmittance and haze have been simulated by the LightTools software, and the results show that with the increasing of the aspect ratio, the haze rises first and drops later while the transmittance decreases all the time. Later, the mold with uniform micro sphere lens arrays arranged in regular triangle has been fabricated successfully by the ball embossing method. Then, the micro sphere lens arrays diffuser with aspect ratio of 0.19, 0.23, 0.26 and 0.29 have been made using the hot embossing method in polypropylene (PP) substrate. Last, haze and transmittance of the micro sphere lens arrays PP diffuser made are verified both by experiment and simulation and the results of experiment and simulation are consistent well.
Abstract: To consider the effective utilization of plastics and agricultural wastes, rice straw fibre was extracted from agricultural wastes, and then composited with polylactic acid(PLA). The thermal stability of straw/poly(lactic acid)(straw/PLA) composites decreased (Thermogravimetric Analysis, TGA). Tensile strength, fracture strain and sharply impact strength of straw/PLA were decreased with the increase of filler content and grain size of straw. Yong’s modulus were increased as the increasing of straw content.
Abstract: A proton exchange membrane of poly (vinylidene fluoride) grafted onto poly (2-acrylamido-2-methylpropane sulfonic acid) (PVDF-g-PAMPS) was prepared as follows: acrylamido-2-methylpropane sulfonic acid (AMPS) was first added to a N-Methyl pyrrolidone (NMP) solution containing poly (vinylidene fluoride) (PVDF) that was modified with plain sodium silicate. Ammonium persulfate was then added as an evocating agent and PAMPS was directly grafted onto the PVDF that was modified with plain sodium silicate. The influences of AMPS contents on the proton conductivity and methanol permeability were studied. The results showed that AMPS is easily grafted into PVDF modified by Plain sodium silicate (Na4SiO4), with increasing of the content of 2-acrylamido-2-methylpropane sulfonic acid, the methanol permeability became large gradually of PVDF-g-PAMPS membranes was increased.
Abstract: The application of activated carbon (AC) supported Fe-Cu-K catalyst for Fischer-Tropsch synthesis (FTS) is studied. The catalyst prepared using the AC as support showed remarkably improvement of reaction performance. The improvement of the reaction performance obtained for the AC is probably ascribed to the physical structure and surface chemistry of AC. The support and corresponding catalyst are characterized by N2 adsorption. Catalytic performance of the catalyst during FT synthesis was excellent. Syngas conversion was about 74%, whereas methane selectivity was low (~2 %).
Abstract: Hydroxyl terminated lactic acid prepolymer was synthesized with poly ethylene glycol (PEG).The malaya acid anhydride modified PLA by fuse polymerization, and the different technological conditions (temperature, reaction time and so on) were discussed by the orthogonal design approach. The result of the orthogonal test indicated that, the product molecular weight had enhanced greatly with the Malaya acid anhydride and the PLEG mass ratio 1:15, at 130°C for 15h. The products were characterized by DSC, IR and SEM, Mechanics performance and water affinity performance of the products was determined, and the degradation behavior in vitro simulated bioenvironmental condition was studied. Mechanics performance was improved, and the good water affinity performance biodegradability was maintained.
Abstract: LaF3 powder is prepared by means of three methods . The traditional precipitation of LaC13 with HF action, sol-gel of La (CH3COO) 3 with NH4F action then gel is handled by infrared furnace and microwave method of La (CO3)3 as La source with NH4F action to become LaF3 Ultra-fine powder under the action of microwave. Through the SEM photographs, it can be revealed that the powder particles are different. Precipitation particles diameter is 10 μm; sol-gel method of particle is 1 um and there are a lot of needle-like particles; microwave particles is 100nm.
Abstract: Reaction-bonding sintering silicon carbide (RB-SiC) toughened by 10vol% short carbon fibers were produced by Gel-casting method using water soluble epoxy as gel former and then reaction sintering at 1750°C under vacuum atmosphere for 2 h . SEM showed that short carbon fibers could disperse uniformly in the preforms and sintered carbon fiber reinforced silicon carbide composites (Cf/SiC). The mechanical test results showed that the strength decrease from 286 MPa for RB-SiC to 231 MPa for Cf/SiC, however, the fracture toughness of Cf/SiC increased from 3.65 MPa m1/2 to 5.28 MPa m1/2 compared with RB-SiC. The strength decrease of the Cf/SiC should be ascribed to the chemical reaction between the addition of short fibers and matrix, and the increase of the fracture toughness could be attributed to fiber debonding, fiber pull-out and crack deflection .
Abstract: Abstract: On the basis of Reddy’s higher order shear deformation plate theory and the von Kármán’s geometry nonlinear theory, governing equations for nonlinear thermal buckling and post-buckling of symmetry angle-ply laminated composite beam subjected to a temperature rise are derived, in which the stretching-bending coupling terms produced by the non-homogenous distribution of the material properties are included. By using the shooting method to solve the corresponding nonlinear boundary value problem, numerical solutions for thermal post-buckling of symmetry angle-ply shear deformation laminated composite beam with its both ends immovably simply supported under uniform temperature rise are obtained. As an example, equilibrium paths and configurations for laminated composite beam paved in term of 45/90 are presented and characteristic curves of the nonlinear deformation changing with the thermal load were plotted. The effects of the geometric and physical parameters on the deformation of the beam are also examined. The theoretical analysis and numerical results show that different thermal expansion coefficient ratio, elastic moduli ratio, will influence of the non-dimension critical buckling temperature.
Abstract: Abstract: Conductive polypyrrole(PPy)-polylactic Acid(PLA) composite membranes are prepared with chemical method. Membranes have been characterized by Fouier transform infrared spectroscopic(FT-IR) and scanning electron microscopy （SEM).The conductive stability of membranes has been measured by home-made multiwell direct current electrical stimulating system. The results show PPy nanparticals network embeds in PLA matrix and the conductive stability of membranes sustains in the range of 28μA~35μA between the observation time of 560h to 1146h.
Abstract: The lignin/PE composites with different compatibilizing agents were extruded and the tensile properties have been tested. The weight ratio of PE, ligin and PE-a-MAH were 7.5%, 10%and 12.5wt%; the weight ratio of PE, ligin and PP-a-MAH were 5%, 7.5% and 10wt% respectively. Scanning Electron Microscopic (SEM) was used to characterize the morphology of the composites. The tensile strengths of lignin/PE composites with PE-g-MAH were higher than that one with PP-g-MAH. Both of them were higher than that one without any compatibilizing agent. And PE-g-MAH was the better compatibilizing agent confirmed by the mechanical tests and SEM results.