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51.
P Riegel FI Freitas G Prévost C Andronescu F Bimet M Kiredjian E Estrangin JP Emond S Dellion B Halioua H Monteil O Patey 《Canadian Metallurgical Quarterly》1997,16(8):610-614
Thirty-eight nontoxigenic strains of Corynebacterium diphtheriae isolated between 1987 and 1992 from clinical specimens of French patients were typed by biotyping, antibiograms, bacteriophage typing, ribotyping, and restriction analysis by pulsed-field gel electrophoresis (PFGE). Excellent correlation occurred between the genotypes defined by PFGE SfiI profiles or by ribotype BstEII profiles. Genotyping revealed seven genotype patterns among the 26 biotype mitis isolates, five among the nine biotype gravis isolates, and three among the three biotype belfanti isolates. Phage typing was nonreactive for nine of the 38 isolates. A combination of all the typing methods led to the identification of 19 different types of Corynebacterium diphtheriae. 相似文献
52.
53.
Silvia Ioan Raluca Marinica Albu Ecaterina Avram Iuliana Stoica Emil Ghiocel Ioanid 《应用聚合物科学杂志》2011,121(1):127-137
A novel quaternized polysulfone with N‐dimethyloctylammonium groups was investigated with respect to its surface properties, hydrophobicity, interactions with blood, and morphology. The history of the films formed from N,N‐dimethylformamide/methanol and N,N‐dimethylformamide/water solutions and the compositions of the solvent/nonsolvent mixtures influenced the surface morphology. Thus, atomic force microscopy investigations of the films showed pores and nodules of different sizes and intensities, which depended on the content of methanol or water in the solvent mixtures. Hydrophilicity modification, evidenced by the apolar components and the electron‐acceptor and electron‐donor parameters of the polar components of the surface tension parameters, was correlated with atomic force microscopy data. Surface wettability trends were analyzed on the basis of the free energy of hydration between the prepared films and water and the work of adhesion. The adhesion of red blood cells to the modified polysulfone showed the influence of the hydrophobic properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
54.
A series of blends obtained from polysulfone (PSF) or chloromethylated polysulfone (CMPSF) and poly(vinyl alcohol) (PVA) in N‐methyl‐2‐pyrrolidone were investigated by means of attenuated total reflection Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), rheology and atomic force microscopy (AFM). Mechanisms through which specific interactions developed via hydrogen bonding in ternary systems affect the blend properties were established from FTIR spectra. The results confirm the presence of hydrogen bonding in PSF/PVA and CMPSF/PVA blends at 0.5 and 0.75 weight fractions of PVA, respectively. Consequently, the type of interactions and structural peculiarity of polymers in the blends as well as the composition of polymer mixtures modify the rheological functions, evidencing the orientation or mobility of chain segments in the shear field. The results derived from rheological measurements are consistent with those above, evidencing significant changes for blends with a greater amount of PVA (i.e. 50/50 and 25/75 (w/w) PSF/PVA and CMPSF/PVA blends, respectively). These blends represent the optimum compositions and possess specific properties, confirmed by the glass transition temperatures. Additionally, the specific microarchitecture of the blends, determined using AFM, represents excellent scaffolds as porous membranes for biomedical applications. © 2014 Society of Chemical Industry 相似文献
55.
The synthesis and characterization of gel and porous strong base anion exchangers with N-methylimidazolium functional groups and the evaluation of their chemical stability in aggressive media and thermal behavior are reported. Strong base exchange capacity values, FT-IR spectroscopy as well as ESEM images proved the content of ionic groups and the morphology structure of the anion exchange resins.Both synthesized resins presented a very good chemical stability in hydrogen peroxide compared to the commercial strong base anion exchange resin, Amberlite IRA-400. It was also shown that the porous strong base anion exchange resin exhibited a better stability in aggressive media of high concentration than gel-type resin. The thermal stability of the samples was evaluated by dynamic thermogravimetric analysis in nitrogen gas. Comparing the TG and DTG curves it can be found that the degradation curves of the samples are close to each other in shape under the heating rate conditions. The differences for the samples between in the different heating rate are the typical temperatures and the residue rate of the decomposition. 相似文献
56.
This paper is concerned with the conformational characteristics of polysulfone in dilute solutions of N,N-dimethylformamide, as evidenced by viscometric data, in order to use these results in more complicated structures with different properties and applications. The dependencies of the solution properties on the molecular weight oligomers and in higher molecular weight regions were quantitatively explained, by considering the effects of chain ends and chain stiffness, according to Yamakawa theory. 相似文献
57.
Vasilescu Cora Drob Silviu Iulian Osiceanu Petre Moreno Jose Maria Calderon Prodana Mariana Ionita Daniela Demetrescu Ioana Marcu Maria Popovici Ion Alexandru Vasilescu Ecaterina 《Metallurgical and Materials Transactions A》2017,48(1):513-523
Metallurgical and Materials Transactions A - A new Ti-20Zr-5Ta-2Ag alloy was elaborated and characterized regarding its microstructure, its native passive film composition and thickness, its... 相似文献
58.
Cornelia Luca Ig. Poinescu Ecaterina Avram Aurelia Ioanid I. Petrariu A. Carpov 《应用聚合物科学杂志》1983,28(12):3701-3706
Several macroporous styrene–divinylbenzene copolymers were prepared using different diluents. The copolymers were chloromethylated with monochlor methyl ether and aminated with N,N-dimethyl-2-hydroxyethylamine in order to perform strongly basic anion exchanger, type II. It was established that the network morphology of anion exchanger determines its ion-exchange rate. It was, also established, by means of transmission electron microscopy, that chloromethylation reaction led to the morphological changes in the macromolecular network of the copolymers. 相似文献
59.
Dana Gingasu Ioana Mindru Luminita Patron Gabriela Marinescu Floriana Tuna Silviu Preda Jose Maria Calderon-Moreno Cristian Andronescu 《Ceramics International》2012
Copper gallate spinels, CuGa2O4, have been synthesized by two wet chemical routes: precursor method and self-propagating combustion involving a glycine-nitrate system. All complex precursors have been characterized by chemical analysis, infrared spectroscopy (IR), ultraviolet visible spectroscopy (UV–vis), electron paramagnetic resonance spectroscopy (EPR), thermal analysis and scanning electron microscopy (SEM). The copper gallate spinel oxides have been further investigated by X-ray diffraction (XRD), SEM, IR, UV–vis, magnetic measurements and EPR. The crystallite size of the copper gallate was found about 280 Å. 相似文献
60.
Cristian Pirvu Ioana Demetrescu Paula Drob Ecaterina Vasilescu Cora Vasilescu Mihaela Mindroiu Rodica Stancu 《Progress in Organic Coatings》2010
This paper presents the results regarding the electrochemical stability and surface analysis of a new alkyd paint with low content of volatile organic compounds in comparison with a conventional alkyd paint. The alkyd films were realized on carbon steel substrate. Dry films thickness in 30–35 μm range was obtained. The experimental tests were carried out in 3% NaCl solution at the 25 °C temperature. The electrochemical techniques (electrochemical impedance spectroscopy (EIS), potentiodynamic and Tafel polarization) and surface analysis techniques (AFM, SEM, EDX) were used to evaluate protective properties of the tested paint films. The correlation of all experimental results established that the new alkyd paint with low content of volatile organic compounds presents better protective performances and lower permeability than conventional alkyd paint. AFM, SEM and EDX indicated a compact, homogenous, non-porous and adherent coating. 相似文献