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971.
Thermal properties of bio flour-filled polypropylene bio-composites with different pozzolan contents
H. -S. Kim S. -W. Choi B. -H. Lee S. Kim H. -J. Kim C. W. Cho D. Cho 《Journal of Thermal Analysis and Calorimetry》2007,89(3):821-827
In this study, the thermal properties of bio-flour-filled, polypropylene (PP) bio-composites with different pozzolan contents
were investigated. With increasing pozzolan content, the thermal stability, 5% mass loss temperature and derivative thermogravimetric
curve (DTGmax) temperatures of the bio-composites slightly increased. The coefficient of thermal expansion (CTE) and thermal expansion
of the bio-composites decreased as the pozzolan content increased. The glass transition temperature (T
g), melting temperature (T
m) and percentage of crystallinity (X
c) of the bio-composites were not significantly changed. The thermal stability, thermal expansion and X
c of the maleic anhydride-grafted PP (MAPP)-treated bio-composites were much higher than those of non-treated bio-composites
at 1% pozzolan content due to enhanced interfacial adhesion. X-ray diffraction (XRD) analysis confirmed the crystallinity
of pozzolan-added bio-composites. From these results, we concluded that the addition of pozzolan in the bio-composites was
an effective method for enhancing the thermal stability and thermal expansion. 相似文献
972.
Multilayer poly(vinyl alcohol)-adsorbed coating on poly(dimethylsiloxane) microfluidic chips for biopolymer separation 总被引:1,自引:0,他引:1
A poly(dimethylsiloxane) (PDMS) microfluidic chip surface was modified by multilayer-adsorbed and heat-immobilized poly(vinyl alcohol) (PVA) after oxygen plasma treatment. The reflection absorption infrared spectrum (RAIRS) showed that 88% hydrolyzed PVA adsorbed more strongly than 100% hydrolyzed one on the oxygen plasma-pretreated PDMS surface, and they all had little adsorption on original PDMS surface. Repeating the coating procedure three times was found to produce the most robust and effective coating. PVA coating converted the original PDMS surface from a hydrophobic one into a hydrophilic surface, and suppressed electroosmotic flow (EOF) in the range of pH 3-11. More than 1,000,000 plates/m and baseline resolution were obtained for separation of fluorescently labeled basic proteins (lysozyme, ribonuclease B). Fluorescently labeled acidic proteins (bovine serum albumin, beta-lactoglobulin) and fragments of dsDNA phiX174 RF/HaeIII were also separated satisfactorily in the three-layer 88% PVA-coated PDMS microchip. Good separation of basic proteins was obtained for about 70 consecutive runs. 相似文献
973.
Time-dependent density-functional theory(TDDFT)has been applied to calculate the electronic structure and second-order nonlinear optical(NLO) properties of some organic molecules.The two-dimensional(2-D)charge transfer charateristics of calculated molecules were studied and compared with corresponding experimental results.All the theoretical results agree well with the measurement.For 2-D molecule with two-fold symmetry,the dominant charge transfer is off-diagonal,while for three-fold symmetry 2-D molecule,the dominant charge transfer is not only between branches and central group but also among branches. 相似文献
974.
975.
Reaction of COC12.6H20 with equimolar bis(3,5-dimethylpyrazolyl)methane (dmpzm) produced a mononuclear adduct [Co(dmpzm)Cl2] (1). Treatment of 1 with sodium dicyanamide (dca) afforded a polymeric complex [Co(dmpzm)(μ-dca)2]∞ (2). 1 and 2 were characterized by elemental analysis, IR spectra, thermogravimetric analysis and single-crystal X-ray diffraction. The cobalt atom in 1 adopts a distorted tetrahedral coordination geometry, bound to two N atoms of one dmpzm and two Cl atoms. Complex 2 has a 2D brick-wall network (extended along the bc plane) in which the { [Co(dmpzm)(μ-dca)]2} n^2n+ chains are interconnected by pairs of μ-dca anions along the c axis. The magnetic properties of 1 and 2 were also investigated. 相似文献
976.
Jin‐Yu Sun Zhen Zhao Yong‐Chao Ma Miao‐Li Zhu Xiang‐Dong Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(1):m4-m6
The crystal structure of the title compound, μ‐2‐hydroxybutanedioato‐1κ2O4,O4′:2κ3O1,O2,O4‐nitrato‐2κO‐tris(1,10‐phenanthroline)‐1κ4N,N′;2κ2N,N′‐dicopper(II) nitrate tetrahydrate, [Cu2(C4H3O5)(NO3)(C12H8N2)3](NO3)·4H2O, contains an unsymmetrical dinuclear copper complex with Cu(phen)2 and Cu(phen)(NO3) moieties (phen is 1,10‐phenanthroline) bridged by a malate (2‐hydroxybutanedioate) ligand, which acts as a double‐bridging and tetradentate ligand. As a result of this double‐bridging action, especially the direct coordination of the O atom of one carboxylate group of malate to the two Cu atoms, the Cu⋯Cu distance is only 4.199 (1) Å and the two phen planes are roughly parallel [the shortest interplanar distance is 3.28 (1) Å], exhibiting an obvious intramolecular π–π stacking interaction. 相似文献
977.
978.
Hye-Young Seo Jun-Hyoung Kim Hyun-Pa Song Dong-Ho Kim Myung-Woo Byun Joog-Ho Kwon Kyong-Su Kim 《Radiation Physics and Chemistry》2007,76(11-12):1869-1874
The study was carried out to determine the effects of gamma irradiation on the volatile flavor components including essential oils, of Angelica gigas Nakai. The volatile organic compounds from non- and irradiated A. gigas Nakai at doses of 1, 3, 5, 10 and 20 kGy were extracted by a simultaneous steam distillation and extraction (SDE) method and identified by GC/MS analysis. A total of 116 compounds were identified and quantified from non- and irradiated A. gigas Nakai. The major volatile compounds were identified 2,4,6-trimethyl heptane, α-pinene, camphene, α-limonene, β-eudesmol, α-murrolene and sphatulenol. Among these compounds, the amount of essential oils in non-irradiated sample were 77.13%, and the irradiated samples at doses of 1, 3, 5, 10 and 20 kGy were 84.98%, 83.70%, 83.94%, 82.84% and 82.58%, respectively. Oxygenated terpenes such as β-eudesmol, α-eudesmol, and verbenone were increased after irradiation but did not correlate with the irradiation dose. The yields of active substances such as essential oil were increased after irradiation; however, the yields of essential oils and the irradiation dose were not correlated. Thus, the profile of composition volatiles of A. gigas Nakai did not change with irradiation. 相似文献
979.
Bao‐Zong Li Xun‐Gao Liu Yan‐Fen Peng Bao‐Long Li Yong Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):m41-m44
In the title complex, poly[cadmium(II)‐μ2‐1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene‐di‐μ2‐thiocyanato], [Cd(NCS)2(C12H12N6)]n, the CdII atom lies on an inversion centre in a distorted octahedral environment. Four N atoms from the thiocyanate and 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene (bbtz) ligands occupy the equatorial positions, and two S atoms from symmetry‐related thiocyanate ligands occupy the axial positions. The benzene ring of the bbtz ligand lies about an inversion centre. Single thiocyanate bridges link the CdII atoms into two‐dimensional sheets containing novel 16‐membered [Cd4(μ‐NCS‐N:S)4] rings. The bbtz ligands further link these two‐dimensional sheets into an unprecedented covalent three‐dimensional network for the cadmium–thiocyanate system. 相似文献
980.
The effect of anodic oxidation on high-strength polyacrylonitrile-based carbon fibers has been studied in terms of fiber surface energetics and fracture toughness of the composites. According to contact angle measurements based on the wicking rate of a test liquid, anodic oxidation leads to an increase in surface free energy, mainly due to the increase of its specific (or polar) component. For the carbon-fiber-reinforced epoxy resin matrix system, a direct linear relationship is shown between the specific component and the critical stress intensity factor measured by the single edge notched beam fracture toughness test. From a surface-energetic point of view, the anodic treatment may be suitable for carbon fibers incorporated in a polar organic matrix, resulting in an increased specific component of the surface free energy. Good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices of the resulting composites. Copyright 2000 Academic Press. 相似文献