- [Show abstract] [Hide abstract] ABSTRACT: High-temperature oxidation properties of Cr18Ni30Mo2Al3Nb alloy at various temperatures were studied via mass gain experiments. The high-temperature oxidation kinetics show that the oxidation curves of the alloy follow the parabolic law, and the alloy has excellent oxidation resistance. Surface morphologies and structure of oxide scales were analyzed by SEM and XRD. At 700 degrees C, (Fe0.6Cr0.4)(2)O-3 and a little of Al2O3 are found on the surface. At 800 degrees C, (A10.9Cr0.1)(2)O-3 is the dominate oxides, together with a little Al2O3 and Fe-oxides. At 900 degrees C, the scale is composed of (Al0.9Cr0.1)(2)O-3 and Al-oxides, also contains a little of Fe (Cr, Al)(2)O-4 and MnFe2O4. A dense oxide film is attained at the three temperatures.
- [Show abstract] [Hide abstract] ABSTRACT: Multiwall carbon nanotubes (MWCNTs) were amino-functionalized by 1,2-ethylenediamine (EDA)' triethylenetetramine (TETA), and dodecylamine (DDA), and investigated by fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA). The dispersion of the DDA functionalized MWCNT in DMF is better than that of the MWCNT functionalized by the EDA and the TETA. Carbon nanotubes reinforced epoxy resin composites were prepared, and the effect of the amino-functionalization on the properties of the composites was investigated by differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), and TGA. The composites reinforced by the MWCNTs demonstrate improvement in various mechanical properties. The increase of Tg of the composites with the addition of amino-functionalized MWCNT compared to the Tg of the composites with the addition of unfunctionalized MWCNT was due to the chemical combination and the physical entanglements between amino group from modified MWNTs and epoxy group from the epoxy resin. The interfacial bonding between the epoxy and the amino group of the EDA and the TETA-modified MWCNT is more important than the well dispersion of DDA-modified MWCNT in the composites for the improvement of the mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
- [Show abstract] [Hide abstract] ABSTRACT: : Based on a conceptual model of hydrocarbon microseepage, a macro-sized experimental equipment used the matched mixtures of cement and quartz sand as simulated caprock and its overlying strata is first set up to simulate the processes of hydrocarbon microseepage and its near-surface expressions. The results of the simulation experiments suggest that simulated caprock and its overlying strata have a certain sealed capability; hydrocarbon microseepage is dominated by the pressure of point gas source, and temperature plays only a subordinate role; on the path of hydrocarbon microseepage, the distribution of hydrocarbon concentration is fan-shaped; differential adsorption of alkanes by the simulated caprock and its overlying strata results in the occurrence of a chromatographic effect. Different migrating patterns within simulated caprock are shown by the ratio of i-butane to n-butane. The concentration of hydrocarbon in the surface soil has good correspondence with the pressure of point gas source. These simulation results are significant to further study of the mechanism of anomalies recovered in surface geochemistry exploration.
- [Show abstract] [Hide abstract] ABSTRACT: Using the Wechsler Preschool and Primary Scale of Intelligence, a study was conducted to determine the intellectual ability of 147 four- to seven-year-old preschool children in a high fluoride zone and 83 similarly-aged children from a low fluoride zone. The results show that a high fluoride intake has a clear influence on the IQ of preschool children, manifesting itself primarily as damage to performance intelligence. The study also indicates that the proportion of preschool children living in high fluoride areas that have retarded head development (based on measuring of the circumference) is significantly higher than the low fluoride control group, and that children with this developmental deficient demonstrate a lower IQ than children with normal head development.
- [Show abstract] [Hide abstract] ABSTRACT: To improve the regeneration ability of biomimetic fat cell (BFC), an innovative agent for hydrophobic organic contaminants (HOCs) removal, BFC was modified through introducing 1, 3, 5-benzenetricarboxyl trichloride with trifunctional group and heterocyclic piperazine in this research. Modified biomimetic fat cell (MBFC) has a good lindane removal capacity close to that of BFC and powder activated carbon (PAC), and the lindane removal is 97.68, 96.65 and 98.36% with 7 mg/L lindane initial concentration, respectively. At the same time, 20 mg/L MBFC or PAC is sufficient for 10 microg/L lindane removal, and in 20-60 mg/L doses range the lindane removal by both MBFC and PAC can reach 99.0%; When the doses is below 10 mg/L, MBFC showed better lindane removal than PAC and MBFC even could reach 96.8% lindane removal in 5 mg/L dose. Lindane removal by MBFC could be held on 95% above in first 6-time reuse. Though the lindane removal by MBFC decreased with the reuse time increasing, MBFC still could remove 80 % lindane after 9 times regeneration. In contract with BFC, MBFC showed obvious advantage on the regeneration. The lindane removal mechanism by MBFC, similar with BFC, includes bioaccumulation by MBFC nucleolus-triolein and adsorption by MBFC membrane, and the bioaccumulation is the main way.
- [Show abstract] [Hide abstract] ABSTRACT: A halogen atom terminated Polystyrene (PSt) was prepared by means of atom transfer radical polymerization. Then, the halogen atom was converted into -N3 group and a -N3 terminated PSt was obtained. Finally PSt was grafted onto the surface of single walled carbon nanotube (SWNT) by the reaction of azide group with SWNT. Comparison of X-ray photoelectron spectrometer of N1s electron belonging to -N3 and the surface of SWNT demonstrated that three-membered rings were formed by releasing N2 from -N3 during the reaction. The structure of PSt modified SWNT was characterized by FTIR, UV, Raman spectrum, and TEM. The experimental results showed that the PSt was connected assuredly to SWNT by the covalent bond. TGA data showed that the amount of PSt on the surface of SWNT firstly increased with growing of PSt and then decrease when continues to grow. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
- [Show abstract] [Hide abstract] ABSTRACT: Fat tissue of organism can accumulate hydrophobic chemicals efficiently and the accumulation level has a positive correlation with fat quantity. In this work, based on this characteristic, an innovative agent, that is, biomimetic fat cell (BFC) has been synthesized with interfacial polymerization. BFC has a hydrophobic nucleolus-triolein and hydrophilic membrane-polyamide, through which water, carrying hydrophobic organic contaminants (HOCs), can pass. This process is followed by the accumulation of HOCs. BFC has 97.39% lindane removal ability. This is close to 98.12% lindane removal by powder active carbon (PAC) in aqueous solution and 7 mg/L initial concentration of lindane. BFC can be regenerated easily by organic solvent dialysis in comparison with high temperature or pressure used for PAC regeneration. Lindane removal by BFC may occur through two mechanisms: bioaccumulation by BFC nucleolus-triolein; and adsorption by BFC membrane. Bioaccumulation is the prevailing mechanism.
Shanghai, Shanghai Shi, China
- Department of Material Science and Engineering
Beijing Research Institute of Chemical IndustryPeping, Beijing, China