Preparation of Polyimide/Ionic Liquid Hybrid Membrane for CO2/CH4 Separation.

Imidazole ionic liquids (ILs) have good affinity and good solubility for carbon dioxide (CO2). Such ionic liquids, combined with polyimide membrane materials, can solve the problem that, today, CO2 is difficult to separate and recover. In this study, the ionic liquid (IL) of 1-ethyl-3-methylimidazolium tetrafluoroborate (IL1), 1-pentyl-3-methylimidazolium tetrafluoroborate (IL2), 1-octyl-3-methylimidazolium tetrafluoroborate (IL3), and 1-dodecylimidazolium tetrafluoroborate (IL4) with different contents were added to a polyimide matrix, and a series of polyimide membranes blended with ionic liquid were prepared using a high-speed mixer. The mechanical properties and gas separation permeability of the membranes were investigated. Among them, the selectivity of the PI/IL3 membrane for CO2/CH4 was 180.55, which was 2.5 times higher than the PI membrane, and its CO2 permeability was 16.25 Barrer, which exceeded the Robeson curve in 2008; the separation performance of the membrane was the best in this work.

Effect of Load on the Thermal Expansion Behavior of T700 Carbon Fiber Bundles.

T700 carbon fiber bundles (CFBs) are the primary material used for manufacturing cable-net in a deployable antenna. In this paper, the relationships between the coefficient of thermal expansion (CTE) of T700 CFBs and the experimental load were investigated. The microstructure of T700 CFBs was analyzed with Raman spectra and XRD before and after the thermomechanical test. The measured results indicated that the T700 CFBs that were parallel to the axis had negative expansion characteristics when in a temperature range of -150⁻+150 °C. The thermal strain that occurred during the heating and the cooling thermal cycles had an unclosed curve that served as the loop. When the thermal cycles were the same, the position of the strain loop and the length of the sample exhibited regular change. The average of the CTEs decreased as the experimental load increased. The microstructural analysis suggested that the degree of structural order and the degree of orientation along the fiber axis improved with the experimental load increase. The change of microstructure parameters could be the primary cause of the negative CTE's variation within the T700 CFBs. The experimental results provide some guidelines for improving the cable-net material selection.

[Study on the correlation of epidermal growth factor and Sjoigren's syndrome with atrophic glossitis].

PURPOSE: To investigate the correlation between epidermal growth factor (EFG) and atrophic glossitis (AG) in patients with Sjoigren's syndromes (SS) and explore its pathogenesis. METHODS: Ninety-three patients with SS (60 with AG and 33 without AG) and 20 normal were selected. The concentrations of EGF in saliva were analyzed by ELISA. The expressions of EGF receptor (EGFR) in the epithelial cells of the tongue were assayed by immunohistochemistry. The differences among each group were analyzed with SPSS19.0 software package. RESULTS: The saliva EGF concentrations in SS was lower than that in normal control group(P<0.0001),and EGF concentrations in SS with AG was significantly lower than that in SS without AG (P=0.024). EGF levels in saliva gradually decreased in the mild, moderate and severe atrophic glossitis groups, and there were significant differences among each group(P<0.05). EGFR in the epithelial cells of tongue was lower in SS with moderate and severe AG than in the control group(P=0.009, P=0.037), and there was a significant correlation between EGF and the degree of AG (r=-0.673, P<0.01). CONCLUSIONS: Saliva EGF concentrations decrease significantly in patients with SS and it is closely related to the morbidity of atrophic glossitis.

[Effect of infiltration technique and polishing on the roughness of artificial carious enamel surfaces].

PURPOSE: To study the surface roughness of early carious lesions which were treated with resin infiltration and polished with different materials, and to provide reference for selection of appropriate polishing system. METHODS: Fifty-four labial surface specimens of mandibular incisors were created out of bovine teeth. They were randomly divided into 6 groups. One group was sound enamel group. Another group was early enamel carious group. Other specimens were treated with a partially saturated acidic buffer solution for preparation of initial artificial enamel caries. These initial artificial enamel caries were treated with resin infiltration. Then they were randomly divided into 4 groups according to polishing or not and type of polishing tool (rubber cups, polishing discs, HiLuster polishers). The surface roughness of specimens in all groups were measured with Form Talysurf PGI 800. Arithmetical mean deviation of the assessed profile (Ra) and the maximum height of the profile(Rz) were used as measurement parameter. SPSS 17.0 software package was used for data analysis. RESULTS: Comparison of sound enamel surfaces and early carious surfaces revealed no significant difference in surface roughness(P>0.05), but the mean value of the latter one was higher. After infiltration, the roughness of surfaces without polishing was significantly higher than that of early carious surfaces(P<0.05). After infiltration and polishing with different tools, there was no significant difference in surface roughness of every two groups (P>0.05). The roughness of polishing groups after infiltration was significantly smaller than that of group without polished after infiltration (P<0.05). Comparison of polishing surfaces after infiltration and early carious surfaces revealed no significant difference in surface roughness (P>0.05). CONCLUSIONS: After early caries being treated with infiltration technique, the roughness of teeth surfaces increases significantly. Those surfaces should be polished. Rubber cup and polishing discs with smaller granularity are more effective and reasonable as the surface polishing materials.