Advanced Materials Research Vols. 631-632

Abstract: In this work, we developed a method to quantitative analyze the absorption and desorption of N719 dye on TiO₂ nanotube arrays. TiO₂ nanotube arrays were fabricated by anodizing titanium foils in an organic electrolyte using a two-electrode configuration with a platinum mesh as the counter electrode. TiO₂ nanotube arrays were then annealed under 450 °Cfor 3 hours and immersed in N719 dye solution for 24 hours. The dye-sensitized TiO₂ nanotube arrays were soaked in an electrolyte solution and stored in a dark closed vessel for 76 days. Then they were desorbed by KOH solution (pH=10). According to UV-visible absorption spectra and Lambert-Beer's law, the desorption rate of N719 dye on 9 µm thick TiO₂ nanotube arrays was calculated to be 36%. The results provide a valuable reference to study the dye desorption and stability of the dye-sensitized solar cells.

Abstract: According to the problem of the joint performance degradation in melting nitinol alloy wire connection, the method of melting-pressure connection applying plasma arc welding as melting heat source was designed and the special flexible fixture was invented to realize the welding process. the Φ2mm nitinol alloy wire connected by this method is shaped well . The characteristic of the welded joint microcosmic formation shows that the grains appear rheological pattern in heat-affected zone. The tensile strength of the joint by plasma arc melting-pressure welding after annealing is 89% of the base metal, it also increases by 43% comparing with the plasma fusion welding joint. The shape memory of the joint is about 97.1% of the base metal, which is higher than the fusion weld joints by 3.3% .

Abstract: Based on our previous work, the present work intends to reveal the origin of the process-parameter effects in fabricating polymer micromixers using microinjection molding. First of all, the effects of the process variables including the melt temperature, injection velocity, packing pressure and packing time, on replication quality of the micromixers were numerically investigated using Moldex3D software. The simulation results were found to agree well with the reported experimental ones, that’s, among the investigated variables, the melt temperature was the only significant factor influencing the replication quality of the micromixers. Moreover, the rheology behavior and the cooling behavior of the PMMA melt were analyzed and identified as the origins of the process-parameter effects.

Abstract: It is difficult to fabricate complicated ceramic parts with conventional manufacturing methods such as injection molding and slip casting. In this paper, an indirect solid freeform fabrication process based on Stereolithography (SL) and gelcasting to shape complicated ceramic parts. A lost resin mold with negative image of part was first fabricated by SL. And then aqueous ceramic slurry with high solids loading and low viscosity were prepared and poured into the resin mold, a wet gelcast body was obtained by in-situ polymerized, and the vacuum freeze-drying technology was used to eliminate the deionized water in the gelcast body for improving efficiency and decrease drying shrinkage. Based on the thermogravimetric analysis results of resin mold and gel ceramic body, a sintering process was carried out to remove mold, organic binder and to sinter ceramic. Finally, the desired ceramic part was successfully fabricated to verify the feasibility and effectiveness of the novel process.

Abstract: In order to explore the effect of application of J-4 micro ecological preparation, based on the data from the experiment in the farm of Yixian County, Hebei Province, the research group established a linear mixed effects model , with time as independent variables, age and different formulations as the fixed effects, using spss software for analysis and solving, the results indicate that the model has the extremely good fitting and forecasting effect and method1 is the optimal ratio. The results will shed light on the further study of the role of probiotics .

Abstract: Material removed by mechanical process inevitably causes surface or subsurface damage containing cracks, plastic scratch, residual stress or dislocations. In nano-abrasive jet polishing (NAJP) the material is removed by chemical impact reaction. The chemical impact reaction is validated by contrast experiment with traditional lap polishing process in which the material is mainly removed through mechanical process. Experiment results show the dependence of the abrasive particles on the choice of materials. Even if the abrasive particle and the workpiece are composed of similar components, the machining properties are remarkably different due to slight differences in their physical properties or crystallography etc. Plastic scratches on the sample which was polished by the traditional mechanical process are completely removed by NAJP process, and the surface root-square-mean roughness has decreased from 1.403nm to 0.611nm. The NAJP process will become a promising method for ultra precision machining method for ultrasmooth optical surface.

Abstract: The effects of electromagnetic stirring and Al₄C₃ grain refiner on the grain refinement of semi-continuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al₄C₃ grain refiner. Electromagnetic stirring can “activate” the Al₄C₃ particles, resulting in more heterogeneous nucleation sites for the primary α-Mg grains. But, longer holding time can “inactivate” the Al₄C₃ particles, and the optimal experimental holding time is 60 min in the present investigation. The activated rate of the electromagnetic under the experimental condition ρ2=1.65%.

Abstract: In this research, a new quaternary ammonium polyether blocked polysiloxane (QBPEAS) was synthesized by reaction of epoxy polyether terminated polydimethylsiloxane with tetramethylethylenediamine. The chemical structure of QBPEAS was characterized by IR and ¹H-NMR. And then the film morphology on fiber substrates was investigated by scanning electron microscope (SEM). The results showed that QBPEAS has a good film-forming ability and can form a macro-smooth Sloane film on the treated fiber surface. In addition, QBPEAS could obviously decrease the bending rigidity and improve the hydrophilicity of the treated fabrics, but has little influence on the fabric whiteness.

Abstract: In this paper,on the basis of a certain kind of Tin bronze alloy,a new nanoparticle reinforced copper alloy with additions of some alloy is produced by using vacuum melting and centrifugal casting technology.The mechanical properties of the alloy have increased significantly than the Tin bronze alloy.The tensile strength, yield strength,elongation of as-cast nanoparticle reinforced copper alloy are 477~535MPa,221~280MPa,28.0~35.6%,respectively.Compared with the conventional Tin bronze alloy, the strength and plastic of the nanoparticle reinforced copper alloy are obviously improved.

Abstract: This study shows the study of optimal surface functionalization of nanoporous alumina membrane for "label-free" DNA detection. Single stranded DNA was first covalently immobilized on the nanopore walls via silane-PEG-NHS linker. The remained NHS group was hydrolyzed to form PEG layer to minimize the unspecific DNA binding during hybridization process. Optimal PEG-silane linker was achieved for better DNA immobilization efficiency. Using this optofluidic device, both ss-DNA immobilization and ds-DNA hybridization were successfully monitored via UV-Vis spectrum montoring. The nanopore size effect on DNA binding efficiency of membranes were also studied. With the increase of nanopore size, the DNA binding efficiency increased due to the increased reacted surface area. This portable optofluidic device integrated with nanoporos alumina membrane has the potential for nucleic acid in field detection in the application of food screening and environmental monitoring with high sensitivity