In this article, we report on a water-soluble self-assembled system that consisted of an acrylamide (AM)-based copolymer and a nonionic surfactant for enhancing oil recovery. The copolymer, denoted as poly(acrylamide-acrylic acid-diallyl dimethyl ammonium chloride-N-allyl benzamide) (PMADN), was synthesized with AM, acrylic acid, diallyl dimethyl ammonium chloride, and N-allyl benzamide, and the nonionic surfactant was Tween 40. The results of our investigation of the ratio of the copolymer to Tween 40 show that the optimal concentrations of PMADN and Tween 40 were 1000 and 500 mg/L, respectively. When it was heated to 115-120 8C for 15 min, the apparent viscosity of the self-assembly system increased 19.2%, and its viscosity retention rate remained at 11.6% under 1000 s 21 . When the system was dissolved in 12,000 mg/L NaCl, 2000 mg/L CaCl 2 , and 2000 mg/L MgCl 2 solutions, the viscosity retention rates were 22.3%, 12.1%, and 17.6%, respectively. In addition, a 2000 mg/L PMADN-Tween 40 solution dramatically enhanced the oil recovery up to 13.4%.

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Electronic assembly technology is in the transition from traditional tin-lead to lead-free. In comparison with Sn-Pb solders, high melting point and poor wettability of the lead-free solders lead to great challenge to present electronic assembly technologies. Inert nitrogen atmosphere can both widen the process window of reflow and improve the mechanical reliability of solder joints. The focus of this study is to investigate the effect of reflow atmosphere on the reflow process and solder joint reliability of lead-free solders (SAC305). Board level reflow in various kinds of atmospheres and microstructural characterization of the solder joint were carried out to demonstrate the influence of controllable atmosphere on the reflow quality of the lead-free solder joints. The SAC305 solder joint fabricated in 1000 ppm O 2 exhibited a good surface morphology and an interface with very small pores. Surface finish of the solder pad was found to have a great influence on the as-reflowed solder joints.

An amidoxime-modified chitosan, featuring favorable porosity and super-lipophilic properties, was successfully prepared for pigment red 224 enrichment.