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71.
将V2O5, CeO2和CuO分散到提取自稻米壳的SBA-16上,考察了其催化CO氧化反应活性,并采用X射线衍射、扫描电镜、透射电镜、程序升温还原和紫外漫反射光谱对所制催化剂进行了表征。结果表明,掺杂CuO的介孔氧化硅是一种有前景的催化剂,其CO转化率可达98%以上。 相似文献
72.
International Journal of Theoretical Physics - Recently, the Mth coherent state (Mth CS) has been defined to be the resultant state of applying the number operator M times on the coherent state... 相似文献
73.
The Interaction between wind flow and structures plays an important role in the computation of civil engineering application. In case of gravity prestressed membrane roofs, the wind lifting forces may exceed the dead load leading to high amplitude structural oscillations, which interact with the flow field. To investigate the interaction a consistent discretization method based on stabilized space‐time finite elements is applied. The flow field is modeled with the incompressible Reynolds Averaged Navier‐Stokes (RANS) equations with an anisotropic eddy‐viscosity turbulence model. The structural motion is described with the theory for geometrically nonlinear elastic deformation behavior, a strong coupling algorithm for the time‐dependent fluid‐structure interaction is implemented. Two applications show the capability of the turbulence model in representing the anisotropic turbulence structure, the differences in the flow field over a bluff body between two configurations representing a rigid and an elastic membrane roof, discusses the structural responses of the roof at a high Reynolds number. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
74.
Francis F Saguez J Cherqui A Vandermoten S Vincent C Versali MF Dommès J De Pauw E Giordanengo P Haubruge E 《Applied biochemistry and biotechnology》2012,166(5):1291-1300
Hydrolytic enzymes involved in chitin degradation are important to allow moulting during insect development. Chitinases are
interesting targets to disturb growth and develop alternative strategies to control insect pests. In this work, a chitinase
from the aphid Myzus persicae was purified with a 36-fold purification rate in a three step procedure by ammonium sulphate fractionation, anion-exchange
chromatography on a DEAE column and on an affinity Concanavalin A column. The purified chitinase purity assessed by 1D and
2D SDS–PAGE revealed a single band and three spots at 31 kDa, respectively. Chitinases were found to have high homologies
with Concanavalins A and B, two chitinase-related proteins, a fungal endochitinase and an aphid acetylhydrolase by peptide
identification by Maldi-Tof-Tof. The efficiency of two potent chitinase inhibitors, namely allosamidin and psammaplin A, was
tested and showed significant rate of enzymatic inhibition. 相似文献
75.
Snow crab is a major fishery in the North Atlantic region. During crab processing the proteins are aerosolized and some are
responsible for development of occupational asthma. Tropomyosin and arginine kinase have recently been reported as major snow
crab allergens. A liquid chromatographic tandem mass spectrometric method has been developed for simultaneous analysis of
these two proteins in air samples collected from processing plants. These proteins were initially isolated then characterized
by use of mass spectrometry to determine their primary structure and signature peptides. The signature peptides were chemically
synthesized in light and heavy forms and used as standards for developing the multiple-reaction monitoring transitions to
monitor allergen levels. A validation study was performed; precision and accuracy were 1.8–8% and 91–104%, respectively. Replicate
air samples were collected on air filters from two crab-processing plants in Newfoundland and Labrador (NL) and four located
in Quebec. In NL, measured levels of both tropomyosin and arginine kinase were between 1 and 20 ng m−3. In Quebec plants, however, levels were found to be much higher at 2–2400 ng m−3. Significant differences were also observed among the plants and individual processing workstations. For the first time arginine
kinase has been detected in its aerosolized form in processing plants. In general, levels of the allergens were highest in
the butchering and cooking areas; plant design can, however, have a significant effect on levels of the allergens. 相似文献
76.
Misfolding and aggregation of proteins is involved in some of the most prevalent neurodegenerative disorders. The importance of collagen stems from the fact that it is one of the dominant component used for tissue engineering and drug delivery applications and is a major component of skin, tendon, bone and other connective tissues. A systematic investigation on the conformation of collagen at various concentrations of glyoxal is studied by various biophysical techniques such as Trp fluorescence, ANS binding, Circular dichroism (CD), ATR-FTIR, Congo red (CR) assay, Rayleigh light scattering and Turbidity measurements. At 60 % (v/v) glyoxal, collagen retains native-like secondary structure, altered Trp environment and high ANS fluorescence, characteristic of molten globule (MG) state. At 80 % (v/v) glyoxal, insoluble collagen aggregates are detected as confirmed by decrease in Trp and ANS fluorescence, increase in non-native β sheet structure as evident from far-UV CD and FTIR spectra, increase in Thioflavin T fluorescence, Rayleigh light scattering, Turbidity measurements, as well as red shift in CR absorbance. 相似文献
77.
Capacitance-voltage measurements of high quality PECVD and MBE grown aluminum nitride (AlN) thin films have been performed. The prepared films have shown polycrystalline (0 0 2)-preferential orientation, and were deposited on p-type Si (1 0 0) substrates with Pt forming the metal gate in a metal-insulator-semiconductor (MIS) configuration. The structure, crystallinity, texture and insulating properties have been found to depend on film thickness and were substantially influenced by the increase of the thickness. C-V measurements of the epitaxial and PECVD films were carried out and their insulating characteristics with increasing thickness (200-1000 nm) were investigated. The epitaxial films exhibited no hysteresis in capacitance behaviour, owing to better crystalline quality over the PECVD grown ones. Capacitance curves versus bias voltage have also been acquired at different temperatures; 10 K, 30 K and 50 K for deposited polycrystalline AlN films of (0 0 2) orientation. We have found that the defects trapped in the Pt/AlN/Si structure played a key role in dominating the overall behaviour of the C-V measurement curves. The trapped charges at the interface between the AlN insulating film and Si substrate caused the capacitance characteristics to shift to negative voltages, and the estimated charge density was of the order of 1010 and 108 cm−2 eV−1 for the PECVD and epitaxial samples respectively. The I-V measurements referred to space-charge conduction mechanism, and the deduced leakage current was found to be of the order of 10−9 A at 200 nm film thickness. 相似文献
78.
S. Anas 《Tetrahedron》2008,64(41):9689-9697
A facile synthesis of substituted alkylidene cyclopentenes through a palladium catalyzed ring opening of fulvene derived bicyclic hydrazines with various organometallic reagents is described. The products are versatile synthons with multiple points for functionalization and can be used in the synthesis of a number of biologically active molecules. 相似文献
79.
Composite waste composed of carbon fibres and polybenzoxazines resin has been pyrolysed in a fixed bed reactor at temperatures of 350, 400, 450, 500 and 700 °C. Solid residues of between 70 and 83.6 wt%, liquid yields 14 and 24.6 wt% and gas yields 0.7 and 3.8 wt% were obtained depending on pyrolysis temperature. The derived pyrolysis liquids contained aniline in high concentration together with oxygenated and nitrogenated aromatic compounds. The pyrolysis gases consisted mainly of CO2, CO, CH4, H2 and other hydrocarbons. The carbon fibres used in the composite waste were separated from the char of the solid residue via oxidation of the char at two different temperatures and investigated for their mechanical strength properties. The carbon fibres recovered from the sample pyrolysed at 500 °C and oxidised at 500 °C exhibited mechanical properties which were 90% of that of the original virgin carbon fibres. Steam activation of the recovered carbon fibres was carried out at 850 °C at different times of activation. The effect of activation time on BET surface area, activated carbon fibres yield, porosity and the morphological structure of activated carbon fibres was evaluated. A maximum BET surface area of over 800 m2 g−1 was obtained for the activated carbon fibres produced at 850 °C for 5 h of activation. Nitrogen adsorption-desorption isotherms showed that the adsorption capacity increased as the activation time increased up to 5 h of activation and then after that decreased. 相似文献
80.
Anas M. Abdel Rahman Sandip Kamath Andreas L. Lopata Robert J. Helleur 《Rapid communications in mass spectrometry : RCM》2010,24(16):2462-2470
Crustaceans are the third most prevalent cause of food‐induced anaphylaxis after peanuts and tree nuts. The severity of the allergenic proteins depends mainly on the amino acid sequence that induces production of IgE antibodies. In black tiger prawn (Penaeus monodon), the crude protein extract was profiled and its allergenic potency was examined against patient's sera. Proteins having strong immunoreactivity with patient's IgE were characterized using peptide mass fingerprinting (PMF). Tropomyosin (TM) (33 kDa), myosin light chain (20 kDa), and arginine kinase (40 kDa) were identified as allergenic proteins. Tropomyosin, the most abundant and potent allergen, was purified using ion‐exchange chromatography for de novo sequencing experiments. Using bottom up tandem mass spectrometry, the full amino acid sequence was achieved by a combination of matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) tandem mass spectrometry (QqToF). Myosin light chain and arginine kinase were also characterized, and their related peptides were de novo sequenced using the same approach. The immunological reactivity of the crude prawn extracts and purified TM samples were analyzed using a large number of patients' sera. A signature peptide was assigned for the TM protein for future quantification work of black tiger prawn TM levels in different matrices (i.e. water, air, food) in the seafood industry. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献