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961.
E. Nguyen Cong Duc L. Fournier C. Levecq B. Lesjean P. Grelier A. Tazi-Pain 《Journal of membrane science》2008
The better understanding of the effective air distribution inside a membrane cassette is a particular challenge in submerged membrane bioreactor. The present study is the first one that investigates the hydrodynamics of the coarse bubbles flow inside a hollow fibre membranes cassette. The experimental investigations were carried out in a reactor equipped with commercial modules from ZENON ZeeWeed® 500d. A bi-optical probe was used to measure the bubble size, the bubble velocity and the gas hold-up at different locations between the modules and for three different gas flow rates. These local measurements gave significant information about the lateral distribution of the air and its evolution with the height on the surface of the membrane modules, which can impact on the filtration performance and are the first step to an optimisation of the aeration system and module geometry. 相似文献
962.
Nga H. Nguyen Brad M. Rosen Xuan Jiang Sven Fleischmann Virgil Percec 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5577-5590
SET‐LRP is mediated by a combination of solvent and ligand that promotes disproportionation of Cu(I)X into Cu(0) and Cu(II)X2. Therefore, the diversity of solvents suitable for SET‐LRP is limited. SET‐LRP of MA in a library of solvents with different equilibrium constants for disproportionation of Cu(I)X such as DMSO, DMF, DMAC, EC, PC, EtOH, MeOH, methoxyethanol, NMP, acetone and in their binary mixtures with H2O was examined. H2O exhibits the highest equilibrium constant for disproportionation of Cu(I)X. The apparent rate constant of the polymerization exhibits a linear increase with the addition of H2O. This is consistent with higher equilibrium constants for disproportionation generated by addition of H2O to organic solvents. Furthermore, with the exception of alcohols and carbonates, the rate constant of polymerization in binary mixtures could be correlated with the Dimroth‐Reichardt solvent polarity parameter. This is consistent with the single‐electron transfer mechanism proposed for SET‐LRP that involves a polar transition state. These experiments demonstrate that the use of binary mixtures of solvents with H2O provides a new, simple and efficient method for the elaboration of a large diversity of reaction media that are suitable for SET‐LRP even when one of the two solvents does not mediate disproportionation of Cu(I)X. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5577–5590, 2009 相似文献
963.
Cam Nguyen 《International Journal of Infrared and Millimeter Waves》1996,17(8):1321-1328
New broadside-coupled coplanar waveguides (CPW) having a completely asymmetrical structure, suitable for hybrid and monolithic microwave and millimeter-wave integrated circuits requiring broad bandwidths as well as loose and tight couplings, is proposed and examined for the first time. The results of the inivestigation, performed based on the spectral-domain analysis, demonstrate the versatility of the asymmetrical broadside-coupled CPW as compared to its symmetrical counterpart. 相似文献
964.
用波长为623.8nm的He-Ne激光作信号光和一束泵浦光,用波长为488.0nm的Ar+激光作另一束泵浦光,在Eu:Fe:LiNbO3晶体中实现了非简并四波混频,获得了波长为488.0nm的变频相位共轭光,同时还产生了波长为632.8nm的同频相位共扼光。本文对上述实验结果进行了定性分析。 相似文献
965.
1-Boryl-3,4-dimethylphosphole trimer: Synthesis, crystal structure and quantum chemical calculations
Nguyen-Nguyen Pham-Tran Pham-Cam Nam Minh Tho Nguyen 《Journal of organometallic chemistry》2006,691(19):4058-4064
A novel cycloadduct of 1-boryl-3,4-dimethylphosphole was prepared by reaction of 3,4-dimethylphospholyl anion with monobromoborane-methylsulfide complex (CH3)2S · BH2Br at −60 °C. It was characterized as a six-membered trimer by spectroscopic means, and its structure confirmed by an X-ray crystal analysis and quantum chemical calculations. Density functional theory calculations (B3LYP) showed that the cyclic trimer is by far more stable than the monomer, dimers or open-chain forms. Various molecular and spectroscopic properties of the borylphosphole monomer and trimer were evaluated. In particular, the changes of the 31P NMR chemical shifts upon oligomerization were examined. The six-membered ring was demonstrated to exist preferentially in a chair-like conformation. Computed NMR chemical shifts (1H, 13C and a lesser extent 31P) appear to be a highly sensitive analytical tool for distinguishing ring conformations having only small energy differences. 相似文献
966.
Spectrally Adjustable Picosecond Dye Laser Pulses Generated with Nanosecond Nitrogen Lasers 总被引:2,自引:0,他引:2
Nguyen Dai Hung Pham Long Dinh Van Trung Nguyen Van Tien Le Hoang Hai Nguyen Ha 《Chinese Journal of Lasers》1995,4(5):385-392
SpectrallyAdjustablePicosecondDyeLaserPulsesGeneratedwithNanosecondNitrogenLasersNguyenDaiHung;PhamLong;DinhVanTrung;NguyenVa... 相似文献
967.
T.L. Uyen Nguyen Mohammad H. Pourgholami Thomas P. Davis Martina H. Stenzel 《European Polymer Journal》2007,43(5):1754-1767
It has been demonstrated that 1,25 dihydroxyvitamin D3 (1,25(OH)2VD3) can inhibit the proliferation of cancer cells, including colorectal and hepatocellular cells which are mainly responsible for liver cancer. However, the use of 1,25(OH)2VD3 is hampered due to the development of hypercalcaemia. We hereby report a promising technique in liver cancer treatment by utilizing crosslinked microspheres prepared by polymerization as a carrier to control the release of 1,25(OH)2VD3 or hydrophobic drug in general at targeted sites over a long period. Microspheres in the size range of 35 μm were prepared and the drug was loaded to these poly(vinyl neodecanoate-crosslinked-ethyleneglycol dimethacrylate) microspheres after polymerization. The release study has shown that up to 1% of the drug was released after 40 days. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and direct contact cytotoxicity assay using HT-20 and L929 confirm the non-toxicity of these spheres. 相似文献
968.
The properties of polyurethane (PU) nanocomposites with three different organoclays were compared in terms of their thermal stabilities, mechanical properties, morphologies, and gas permeabilities. Hexadecylamine–montmorillonite, dodecyltrimethyl ammonium–montmorillonite, and Cloisite 25A were used as organoclays for making PU hybrid films. The properties were examined as a function of the organoclay content in a matrix polymer. Transmission electron microscopy photographs showed that most clay layers were dispersed homogeneously into the matrix polymer on the nanoscale, although some particles of clay were agglomerated. Moreover, the addition of only a small amount of organoclay was enough to improve the thermal stabilities and mechanical properties of PU hybrid films, whereas gas permeability was reduced. Even polymers with low organoclay contents (3–4 wt %) showed much higher strength and modulus values than pure PU. Gas permeability was reduced linearly with an increasing amount of organoclay in the PU matrix. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 670–677, 2002; DOI 10.1002/polb.10124 相似文献
969.
A. Cady R. Pindak W. Caliebe P. Barois W. Weissflog H. T. Nguyen C. C. Huang 《Liquid crystals》2002,29(8):1101-1104
We have performed resonant X-ray scattering on two bent-core liquid crystal compounds exhibiting the B2 phase using three sample geometries: free-standing film and two others with free surface arrangements. The results conclusively demonstrate the two-layer orientational periodicity in this phase suggested by optical studies. We have performed the first resonant scattering experiments on liquid crystals at the chlorine K-edge, opening up a new class of compounds for resonant X-ray scattering studies. Furthermore, we have achieved an excellent alignment of the B2 phase with a free surface. 相似文献
970.