Advanced Materials Research Vols. 236-238

Abstract: Zeolite NaKL was in-situ crystallized under static condition with kaolin microspheres calcined at 980 °C as silicon and aluminium sources. Influences of hydrothermal synthesis conditions such as the mole ratio of n(K₂O)/n(Na₂O), n(OH^-)/n(SiO₂) and crystallizaion time on crystallization of zeolite L were studied in detail. The crystal phase and morphology of the as-prepared zeolite samples were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The results showed that the as-synthesized samples owned characteristic peaks of zeolite L with high crystallinity and were covered uniformly by regular crystal of zeolite L on its kaolin microsphere surface , which maintained complete ball shape as before. The optimum conditions to get zeolite NaKL with high crystallinity by this method were found to be the mole ratio of n(K₂O)/n(Na₂O) =7:3 and n(OH^-)/n(SiO₂) =0.50 in the reaction mixture, an aging of the reactants at room temperature for 30 h and crystallization temperature 120 °C for 24 h.

Abstract: Teak (Tectona grandis L.f) is decay resistance and natural durability. These advantages are relationship with inclusion of teak. For breeding, planting, and the wood used to its best advantage by the end-user, further information concerning the heartwood extractive chemical of different provenances teak is necessary, However, because of limitation of analytical instruments, the extractive chemical components of teak centre on decay resistance relationship with napthoquinone, tectoquinone, and so on, nobody systematacially analyzed heartwood extractive chemical components of different teak. We analyzed and contrasted extractive chemical components of three provenances teak heartwood(Indian, Thailand and Nigeria), and found 109 peak and 74 compounds was identified, the same compounds of 3 provenances were 27. The main compounds were Mequinol, 1,2-benzenediol, 1(3H)-Isobenzofuranone, Vanillin, 1,4-Naphthalenedione, Naphthalene, 1,2,3,4,4a,5,6,8a- octahydro-7-methyl-4-methylene-1- (1- methylethyl), Cyclohexane, 1-ethenyl-1-methyl- 2-(1-methylethenyl)-4- (1- methylethylidene)-, 4,6-Dimethoxysalicylaldehyde, 2-Propenal, 3-(1,3-benzodioxol-5-yl)-, 4-((1E)-3-Hydroxy -1-propenyl) -2-methoxyphenol, 1H-Imidazole, 1-ethyl-, 2-Methylisoborneol, Phthalic acid, phenyl 2-pentyl ester, 1,4-Naphthalenedione, 2-hydroxy-3-(3-methyl-2-butenyl)-, [1,1'-Biphenyl]-2-ol, 5-(1,1-dimethylethyl)-, 9,10- Anthracenedione, 2-methyl-, 1-Hydroxy-4-methylanthraquinone, Indane-1,3-dione, 2-(3-hydroxyphenyl)- 2H-Benzopyran - 2-one, 4-methyl-3-phenyl-, 9,10-Anthracenedione, 1,8-dihydroxy-2-methyl-, 2-(Hydroxymethyl) anthraquinone, 4H-1-Benzopyran-4-one, 3-hydroxy-2-phenyl-, Benzofuran-3-one, 2-[3-hydroxy-4-methoxy benzylidene] -6-hydroxy-, Squalene, .gamma.-Sitosterol, 9,19-Cyclolanost-24-en-3-ol, (3.beta.)-, Cholest-8(14)-en-7-one, (5.alpha.)-.

Abstract: To select a suitable decolorizing resin for crude Tussilago farfara L. polysaccharide(TPS), the decolorization effect of crude TPS by five resins are studied. And the adsorption equilibrium of TPS pigment on the selected resin was investigated.The results show that the decolorization ratios of LS-206 is higher than those of other resins. Under optimized dynamicad sorption conditions (flow rate of 1.5BV/h,2BV of 5mg/ml TPS solution in 298K), the decoloration, deproteinization and polysaccharide recovery ratios of LS-206 resin were 90.04%, 91.42% and 85.38%, respectively. The above results show thatmacroporous anion exchange resins are suitable for the decolorization of crude TPS.

Abstract: In this study, the xyn2 gene, which encodes an endo-β-1,4-xylanase, was isolated with holocellulose extracted from Juncao Miscanthus floridulu as an inducer. The xyn2 gene expressed in Escherichia coli, with the estimated yield of 349 U·mL^-1. Zymogram analysis showed that the purified Xyn2 had only one band on SDS-PAGE with an estimated molecular mass of 28 kDa. Enzymology analysis demonstrated that its optimum activity was at pH 6.0 and 60°C, with stability at pH range 4.0~7.0 and temperature up to 50°C. The metal ions Cu²⁺ and Mg²⁺ showed some inhibition effects, while Fe²⁺ and Fe³⁺ had small stimulating effects. Its values of Km and Vmax are 2.85 mM and 50.2 mM/min, respectively. Based on our results, we propose a novel way to convert Juncao biomass into energy and other useful products.

Abstract: Mg-, Zn-, and Cu-substituted aluminophosphate molecular sieves (MeAPO-5 and MeAPO-11) were synthesized by hydrothermal crystallization method. The n-hexane cracking performance over the as-prepared MeAPOs was estimated under different reaction conditions. MeAPO-5 molecular sieves exhibited higher activity for the cracking conversion in the temperature range of 723~823 K than MeAPO-11. The conversion level of n-hexane over MeAPOs with the same topology had the following order: MgAPOs > ZnAPOs > CuAPOs. The cracking results showed that the conversion level of n-hexane increased with increasing reaction temperatures and contact time, and that the first order is determined in the n-hexane concentration.

Abstract: Hydrogen production by ethanol steam reforming over Ni-Cu/ZnO catalyst in the temperatures range of 250-550°C was studied on a fixed bed reactor. The effects of reaction temperature and water/ethanol molar ratio on hydrogen production were investigated. The structure and surface characteristics of the catalyst were measured by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential thermal analyzer (TG-DSC). The results show that the Ni-Cu/ZnO catalyst has good catalytic performance with higher hydrogen yield of 4.87molH₂/molEtOH reacted. A comparison of hydrogen production from ethanol steam reforming over Ni-Cu/ZnO catalyst with over a commercial catalyst was made in this paper.

Abstract: Bimetallic catalysts PtRh@Pt₅/C with different deposit structures were prepared by force deposition followed calcination at 400°C and characterized by cyclic voltammetry (CV) combined with XRD. The activity of the obtained catalysts was examined in methanol electrooxidation by CV. It was found that PtRh@Pt₅/C catalysts achieved higher catalytic activity and better tolerance to CO compared with Pt₅/C. The surfaces of PtRh@Pt₅/C derived from sandwich-like deposit structure was composed of crystallites and amorphous of PtRh alloys, showing exceptional catalytic activity in methanol oxidation with peak potential shifting 0.03V negatively and 90% increase in current density.

Abstract: The gene, prx II, in mice liver was found to be up-regulated under the stress of AFB₁ in our previous study. In this study, the total RNA from the mice liver was extracted, and followed by the synthesis of cDNA with the RNA as template by the method of reverse transcription. Then, prx II gene fragment was amplified by PCR with the cDNA as template. After double-digestion and ligation reaction, the prokaryotic expression vector pET28a (+)-prx II was successfully constructed and was transformed into E. coli BL21 (DE3). The protein- Prx II was successfully expressed when induced by IPTG, and finally, Prx II was purified by Ni²⁺-NTA affinity chromatography. The molecule structure of Prx II, including its signal peptide, hydrophobicity, and its secondary and tertiary structure, was predicted by bioinformatics analysis. The results showed that no signal peptide was predicted in the molecule of Prx II; Five hydrohpobic domains were predicted in the protein molecule, and the average predictive value for its hydrophobicity was -0.151; There were 35% α-helix (69 residues) and 21% β-pleated sheet (42 residues) in the molecule; The tertiary structure of the protein was constituted by seven α-helices and seven β-pleated sheets.

Abstract: Polylactic fiber is a new renewable and biodegradable polymer material for its better physical property and thermoplastic and biological properties, while there are no corresponding inspection method to characterize and identify polylactic fiber with other fibers. So, the present paper is to qualitative analyze the features of PLA fiber and identify it with general fibers, including Polyester, Polyamide, Polyacrylic, Diacetate, Cotton, Viscose and Silk fibers. Elementary analysis method is utilized to have the definite analysis of fiber purity degree and category by the corresoponding element contents of constructing elements. The experimental results show that there exist good accordance with the theoretical results, and is suitable for qualitative characterizaion and identification of fibers. Gas chromatography mass spectrum method is used to feature marker functional groups of these eight fibers, and to further have a qualitative analysis of each fiber. IR spectroscopy proves the qualitative identification on fiber category by the marker absorbing peaks of functional groups ranging from 650cm^-1-2200cm^-1. These results will be greatly helpful in the qualitative analysis and indectification of Polylactic fiber.

Abstract: Polylactic fiber is a new environment-friendly fiber and has wide application, while there are few studies on its characters and structures. The main content in present paper is to analyze element content and functional group as well as thermal properties. The elementary analysis method shows that the contents of C, H and O elements are 49.83%, 5.63% and 44.54%, respectively; it has good accordance with the theoretical results. Gas chromatography mass spectrum method proves that the functional groups of PLA fiber are lactide and acetaldehyde as well as 2,3-pentanedione, and whose total content is larger than 70%. IR spectroscopy depicts that there exist significant absorbing peaks by -C=O-, -C-O-, -OH- within 1000cm-1-1300cm-1, and -C=O- within 1000cm-1-1300cm-1. The absorbing peak of ultraviolet spectrum is 260 nm avelength. Crystallinity is 61.72% and orientation degree is 93.36% and 84.30% in Full Wave at Half Maximum and in Area calculations based on X-ray. These results will be greatly helpful in the qualitative analysis and indectification of Polylactic fiber.