The preparation technology of micro-nano structure on copper surface is studied and optimized. Aqueous solution containing sodium carbonate and sodium molybdate is used as electrolyte, and the copper sample is anodized at a constant voltage to form a layer of oxidation on the copper surface. Then, the copper surface is treated with aqueous solution containing phosphate and sodium dihydrogen phosphate as corrosion solution to obtain a micro-nano structure on the copper. The surface is observed by using a scanning electron microscope. Finally, the analysis software is used to analyze the scanning electron microscope image to calculate the micro-nano structure pores on the copper surface. The results show that when the anodizing voltage is 15 V, the anodizing time is 20 min, the phosphoric acid mass fraction is 20%, and the corrosion time is 30 min, the copper surface is relatively smooth, and the porosity reaches 25.77%. Orthogonal experiments demonstrate that the type, concentration of the corrosive solution, and etching time have a great effect, while the anodizing electrolyte, voltage and electrolysis have no significant effect on the porosity. Using a combination of anodic oxidation and chemical corrosion, micro and nano junctions with uniform and high porosity can be prepared on the copper surface.
In order to apply the C-H activation strategy to the development of chiral organic catalysts, two novel C3-trimethylsilyl substituted chiral proline catalysts are designed and synthesized using L-proline as the starting material and C(sp 3)-H silylation as the key step, which are applied to the asymmetric aldol reaction of p-nitrobenzaldehyde with acetone and the asymmetric Mannich reaction of imine with β-methylbutyraldehyde, respectively. Both target products can be synthesized with a good enantioselectivity. This strategy effectively enriches the means of structural modification of proline and provids a new method for the development of new silicon-containing organic catalysts.
To understand the adsorption kinetic mechanism of chloropentafluoroethane (R115) on NaX and then to guide the industrial applications of R115 adsorption removal and catalytic conversion, the effect of R115 concentration (referring to volume fraction) and adsorbent particle size on adsorption performance are studied by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The applicability of the Thomas model and Yan model for breakthrough curve analysis are compared. A two-level three-factor experimental method is implemented to evaluate the significance and possible correlations of R115 concentration, adsorbent mass, and flow rate on adsorption performance. The results indicate that the adsorption process is mainly controlled by R115 external film diffusion. The Yan model and the pseudo-first-order adsorption kinetic model fit the experimental data better. The adsorbent mass is the most important factor significantly affecting the breakthrough time, saturation time, volume of effluent treated per gram of adsorbate, and fractional bed utilization. The interaction of adsorbent mass and flow rate has a significant effect on the volume of effluent treated per gram of adsorbate.
In the quantum dot-encoded microspheres based on the suspension array technology, the nonspecific biofouling will decrease the detection sensitivity and the multiplex detection ability. In order to inhibit the nonspecific biofouling, the polyethylene glycol grafted styrene maleic acid copolymer (PEG-g-PSMA) was used as substrate, and the CuInS2/ZnS quantum dot-encoded PEG-g-PSMA fluorescent microspheres were fabricated via the Shirasu porous glass (SPG) membrane emulsification-emulsion solvent evaporation technique. The grafting ratio and the chain length of PEG in PEG-g-PSMA were controlled by adjusting the feed mass and relative molecular mass of methoxy polyethylene glycol (mPEG), respectively. The microspheres were further applied to the immunoassay of CA199. The results of morphology and fluorescence properties show that the prepared microspheres are spherical and monodisperse, with an average particle size of 5 μm, and the internal quantum dots and fluorescence distribution are uniform. Immunoassay shows that the microspheres can significantly inhibit the nonspecific adsorption. When the optimal grafting ratio of PEG is 30 and the relative molecular mass of PEG is 1000, the limit of detection (LOD) to CA199 reaches up to 0.9 kU/L (1 U=1 μmol/min). The PEG-g-PSMA fluorescent microspheres can be prepared in large quantites by this method and have a promising application in multiplex immunoassay.
