Advanced Materials Research Vol. 704

Abstract: In this study we selected polyethylene glycol (400), triethanolamine, silane coupling agent and glycerol as the main raw material, and systematically studied the chemical adsorption film technology on the steel surface by taking one step. Under the optimum conditions ( polyethylene glycol (400) was 10mL/L, triethanolamine was 40mL/L, silane coupling agent was 10mL/L, glycerin was 15mL/L, the pH was 10, the time was 12min, and temperature was 45°C), we characterized the chemical adsorption film by SEM, XPS and IR. The results showed that the treatment process was simple, the tank liquor was stable, the chemical adsorption film was dense, uniform. This adsorption membrane resistance to corrosion and coating adhesion was superior to the traditional phosphating process.

Abstract: Removed at authors request.

Abstract: S)-tert-butyl 3-hydroxybutyrate was synthesized by asymmetric reduction of tert-butyl acetoacetate with Saccharomyces cerevisiae B5 as catalyst. The enantiometric excess of (S)-tert-butyl 3-hydroxybutyrate increased with addition of more amount of substrate. High optical purity of product can be obtained when 6 g/L chloroform was used as inhibitor. The optimum reduction time, temperature, and initial pH of reaction mixture were 60 h, 30 °C, and 6.2. Addition of more biomass and lower amount of substrate helped to get high conversion. Conversion and enantiometric excess of product reached 100% when initial substrate concentration and biomass were 2.0 g/L and 140 g/L with 6 g/L chloroform as inhibitor.

Abstract: In this work, supercritical carbon dioxide with ethanol as cosolvent was employed to extract bioactive compounds from Polygonum Cuspidatum. Effect of temperature for 40 and 50 C on the extraction at 35 MPa was examined. It was found that extraction at 50 C resulted in high yield. A two-stage extraction at 50 C and 35 MPa was then designed to investigate effect of cosolvent on the recovery of resveratrol and emodin. The first stage extraction by solely using carbon dioxide can rarely extract resveratrol, but adding ethanol as cosolvent in the second stage significantly increases the extraction of resverarol and emodin. The crude extract obtained in the second stage was very stable against agglomeration and precipitation, because the first stage extraction helped to remove impurities from the Polygonum Cuspidatum. The stable crude extract was subsequently used as the feed for the SMB (simulated moving bed) separation. In this work, experimental validation was completed by solely using single SMB to isolate resveratrol, emodin, and physcion from the crude extract. As conducting the SMB experiments, the Triangle theory was used to help to determine the separable operating conditions. From the discussion of the experimental results, the criterion to obtain the pure resveratrol and physcion, and the concentrated emodin were depicted. Since both the extraction and the purification are conducted at low temperature, the bioactivity of the produced natural products will totally be preserved. The two-stage extraction and subsequent purification in this paper will provide greener and effective alternative for the development of botanical drugs.

Abstract: Alternating surface oxide and hardened layers were fabricated by means of anodic plasma nitrocarburizing of low-carbon steel in aqueous ammonium chloride/carbamide solutions. The effect of electrolyte composition and treatment conditions on the phase characteristics, structure and properties of the surface layers was studied. The distributions of hardness, phase and structure composition of the surface layers were defined. Controllability of diffusion saturation with nitrogen and carbon by variation of electrolyte composition and treatment temperature was shown. The formation of nitrogen and carbon, which are diffusing into the steel surface at anodic plasma electrolytic nitrocarburizing was described.

Abstract: Review of results in anodic plasma electrolytic saturation of structural steels with nitrogen and carbon in the aqueous electrolytes containing ammonia chloride and required additional constituents is presented. Proposed nitrohardening technology of the medium-carbon steels includes the short-time nitrogen saturation with the following hardening in the electrolyte. Short-time anodic carburizing possibility of the low-carbon steels with following hardening is shown. Treatment samples microhardness is 630±30 HV, their surface roughness decreases from 1.2 to 0.22 μm.

Abstract: In order to gain deeper insight into the interaction mechanism between bovine serum albumin (BSA) and polyethylene glycol (PEG), the present work applied elastic light scattering (ELS) spectroscopy to investigate the interaction between BSA and PEG, and explore the effects of concentration and molecular weight of PEG on the interaction at physiological pH. The results showed that the interaction force existed between linear PEG and spherical BSA molecules was mainly hydrogen bonding. In addition, the apparent binding constant of system was evaluated by model calculation.

Abstract: Degradation of printing and dyeing wastewater after aerobic biochemical treatment by photocatalysis is studied by using a rotating photoreactor and TiO₂ photocatalyst of Degussa P25. Effects of irradiation time and pH value on removing efficiency are investigated. The results show that the COD down to about 80mg/L can be achieved at the irradiation time of about 4-5 hours at mild pH values. At the pH value from 1.5 to 3.2, the COD down to about 80mg/L can be achieved at the irradiation time less than 1 hour, and the COD down to about 20mg/L could be achieved at the irradiation time of about 4 hours at a pH value of about 3.2.

Abstract: New algorithm has been offered to divide a concentration complex of reciprocal system for the subsystems. It is based on the relations between the number of complex polyhedron vertexes and resulting number of simplexes. Method is demonstrated on the quaternary systems. It is easy realized in the software, and is very effective in the cases with inner points (compounds) and with the competition of inner diagonals.