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991.
992.
Two ionic liquids (IL), namely, 1-methyl-3-octylimidazolium chloride (MOIC) and trihexyltetradecylphosphonium tetrafluoroborate (TTPT) were used to prepare polar and nonpolar sol–gel coatings for capillary microextraction (CME). Bis[(3-methyldimethoxysilyl)propyl] polypropylene oxide (BMPO), containing sol–gel active terminal methoxysilyl groups and polar propylene oxide repeating units, was used to prepare polar sol–gel hybrid organic–inorganic coatings. Hydroxy-terminated poly(dimethyl-co-diphenylsiloxane) was used as the sol–gel active organic component for nonpolar sol–gel hybrid coatings. Compared to a sol–gel BMPO coating prepared without IL, the sol–gel BMPO coatings prepared with the use of both of these ILs provided more efficient extraction as is evidenced by more pronounced GC peak areas. The MOIC-mediated sol–gel BMPO coating provided larger GC peak areas compared to the TTPT-mediated sol–gel BMPO coating. Scanning electron microscopy results suggested that MOIC provided a more porous morphology of the sol–gel BMPO extraction media compared to that prepared with TTPT. Thus, individual ILs can affect the porosity of sol–gel materials to different degrees. Overall, the sol–gel BMPO coating prepared with the ILs could extract nonpolar to polar analytes directly from aqueous samples. Detection limits were on the order of nanograms per liter (1.9–330.5 ng/L) depending on the analyte class. Furthermore, the MOIC-mediated sol–gel BMPO coating demonstrated high thermal stability (330 °C), solvent resistance, and fast extraction equilibrium (10–15 min) for polar and moderately polar analytes. 相似文献
993.
AnL
1-existence theorem is proved for the nonlinear stationary Boltzmann equation with hard forces and no small velocity truncation—only
the Grad angular cut-off-in a setting between two coaxial rotating cylinders when the indata are given on the cylinders. 相似文献
994.
995.
The effectiveness of stabilisers, organic (hindered amine light stabilisers), inorganic (nanoparticulate zinc oxide), and combinations thereof, in preventing the signatures of degradation in polypropylene subjected to accelerated weathering is studied. Not only the type of stabiliser but also its distribution is important for stabiliser efficiency. The spatial effects of stabilization are studied using positron spectroscopy depth profiling. 相似文献
996.
Anne Hansen 《BMC neuroscience》2007,8(1):64
Background
The nasal cavity of all vertebrates houses multiple chemosensors, either innervated by the Ist (olfactory) or the Vth (trigeminal) cranial nerve. Various types of receptor cells are present, either segregated in different compartments (e.g. in rodents) or mingled in one epithelium (e.g. fish). In addition, solitary chemosensory cells have been reported for several species. Alligators which seek their prey both above and under water have only one nasal compartment. Information about their olfactory epithelium is limited. Since alligators seem to detect both volatile and water-soluble odour cues, I tested whether different sensory cell types are present in the olfactory epithelium. 相似文献997.
Micha?l?Canipelle Sébastien?Tilloy Anne?Ponchel Hervé?Bricout Eric?MonflierEmail author 《Journal of inclusion phenomena and macrocyclic chemistry》2005,51(1-2):79-85
Interactions between the meta-substituted monosulfonated triphenylphosphine and chemically modified β-cyclodextrins were investigated in aqueous solution by NMR and UV–vis spectroscopy. Titration and continuous variation plots obtained from 31P NMR data indicate that the monosulfonated triphenylphosphine forms 1:1 inclusion complexes with the 2-hydroxypropylated β-cyclodextrin, the methylated β-cyclodextrin and the (2-hydroxy-3-trimethylammoniopropyl)-β-cyclodextrin chloride. These inclusion complexes are more stable that those formed with native β-cyclodextrin, confirming that poisoning of the chemically modified β-cyclodextrins by the hydrosoluble phosphine occurs when modified cyclodextrins are used as mass transfer promoters in aqueous-phase organometallic catalysis.This revised version was published online in July 2005 with a corrected issue number. 相似文献
998.
999.
Naban-Maillet J Lesage D Bossée A Gimbert Y Sztáray J Vékey K Tabet JC 《Journal of mass spectrometry : JMS》2005,40(1):1-8
Internal energies and energy distributions were studied using the 'survival yield' method developed previously. In addition to conventional benzylpyridinium salts, protonated esters (fragmenting by rearrangement) and protonated leucine enkephalin were also used, extending the validity of the technique. Fragmentation processes were studied in the cone voltage region and modeled by the RRKM-based MassKinetics program. The results show that the shapes of the energy distributions are similar to thermal distributions. The mean internal energies are very similar for all compound classes studied, and show a linear increase with collision energy in the 10-50 eV region. 相似文献
1000.
Michael?Y?Chao Jonah?Larkins-Ford Tim?M?Tucey Anne?C?HartEmail author 《BMC neuroscience》2005,6(1):45