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111.
Calabrese V Quici S Rossi E Cariati E Dragonetti C Roberto D Tordin E De Angelis F Fantacci S 《Chemical communications (Cambridge, England)》2010,46(44):8374-8376
7-N,N-Dibutylamino-2-azaphenanthrene (L(3)), 8-N,N-dibutylamino-2-azachrysene (L(4)) and related Ir(i) complexes or alkylated salts show high second-order NLO responses, as determined by the EFISH technique and DFT calculations. L(4) is appealing as building block for NLO active materials due to its unexpected large μβ(1.907)value and its very high thermal stability. 相似文献
112.
113.
Pulvirenti and Toscani introduced an equation which extends the Kac caricature of a Maxwellian gas to inelastic particles. We show that the probability distribution, solution of the relative Cauchy problem, converges weakly to a probability distribution if and only if the symmetrized initial distribution belongs to the standard domain of attraction of a symmetric stable law, whose index ?? is determined by the so-called degree of inelasticity, p>0, of the particles: $\alpha=\frac{2}{1+p}$ . This result is then used: (1) To state that the class of all stationary solutions coincides with that of all symmetric stable laws with index ??. (2) To determine the solution of a well-known stochastic functional equation in the absence of extra-conditions usually adopted. 相似文献
114.
Park JH Derfus AM Segal E Vecchio KS Bhatia SN Sailor MJ 《Journal of the American Chemical Society》2006,128(24):7938-7946
This paper describes a method for local heating of discrete microliter-scale liquid droplets. The droplets are covered with magnetic porous Si microparticles, and heating is achieved by application of an external alternating electromagnetic field. The magnetic porous Si microparticles consist of two layers. The top layer contains a photonic code and it is hydrophobic, with surface-grafted dodecyl moieties. The bottom layer consists of a hydrophilic silicon oxide host layer that is infused with Fe3O4 nanoparticles. The amphiphilic microparticles spontaneously align at the interface of a water droplet immersed in mineral oil, allowing manipulation of the droplets by application of a magnetic field. Application of an oscillating magnetic field (338 kHz, 18 A rms current in a coil surrounding the experiment) generates heat in the superparamagnetic particles that can raise the temperature of the enclosed water droplet to >80 degrees C within 5 min. A simple microfluidics application is demonstrated: combining complementary DNA strands contained in separate droplets and then thermally inducing dehybridization of the conjugate. The complementary oligonucleotides were conjugated with the cyanine dye fluorophores Cy3 and Cy5 to quantify the melting/rebinding reaction by fluorescence resonance energy transfer (FRET). The magnetic porous Si microparticles were prepared as photonic crystals, containing spectral codes that allowed the identification of the droplets by reflectivity spectroscopy. The technique demonstrates the feasibility of tagging, manipulating, and heating small volumes of liquids without the use of conventional microfluidic channel and heating systems. 相似文献
115.
Cavalieri F Chiessi E Finelli I Natali F Paradossi G Telling MF 《Macromolecular bioscience》2006,6(8):579-589
Polysaccharide hydrogels have found several applications in the food industry, in biomedicine, and cosmetics. The study of polysaccharide hydrogels offers a challenging scenario of intrinsic heterogeneities in the crosslinking density and large time and space ranges that characterize a number of dynamic processes entailing segmental motions, water diffusion, and small-molecule diffusion. The understanding of such complex features is essential because of the extensive use of polysaccharidic moieties in the food industry, biomedical devices, and cosmetics. The study of phenomena occurring at the nanoscale to the mesoscale requires the combination of investigative tools to probe different time and distance scales and the structural characterization of the networks by established methodologies such as swelling and elastic modulus measurements. Elastic and quasielastic neutron scattering, and fluorescence recovery after photobleaching are emerging methodologies in this field. In this feature article we focus, somewhat arbitrarily, on these new approaches because other techniques, such as low-resolution proton NMR relaxometry and rheology, have been already described thoroughly in the literature. Case examples of polysaccharide hydrogels studied by neutron scattering and fluorescence recovery are presented here as contributions to the comprehension of the dynamic behavior of physical and chemical hydrogels based on polysaccharides. Quasielastic incoherent neutron scattering experiment on a Sephadex hydrogel sample at different temperatures. 相似文献
116.
Caro E Marcé RM Cormack PA Sherrington DC Borrull F 《Journal of separation science》2006,29(9):1230-1236
A molecularly imprinted polymer (MIP) has been prepared for the first time with ciprofloxacin (CIPRO) as the template molecule, via a noncovalent synthetic procedure. Prior to its use as a sorbent in SPE, the MIP was evaluated chromatographically to confirm that it was indeed molecularly imprinted. The MIP was then used to extract CIPRO selectively from urine samples by means of a two-step SPE procedure in which a commercial Oasis cartridge and a molecularly imprinted SPE cartridge were combined in series. This approach allowed the matrix compounds present in the samples to be removed effectively. The urine extracts obtained after this two-step SPE procedure was applied were relatively clean compared to the original samples, and this made it possible to inject directly the extracts into a mass spectrometer and thus quantify CIPRO in urine samples at low levels and reduce the time of analysis. 相似文献
117.
Ester S. B. Ferreira Alison N. Hulme Hamish McNab Simon Parsons Anita Quye 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(2):211-212
The geometry of the title compound, 2-methoxy-1-(2,4,6-trihydroxyphenyl)ethanone, C9H10O5·H2O, is determined by the presence of an intramolecular hydrogen bond; the geometry of the benzene ring is distorted by a flanking carbonyl group. 相似文献
118.
Ester Mateo Ruth Lahoz Germn F. de la Fuente Andrs Paniagua Joaquín Coronas Jesús Santamaría 《Journal of membrane science》2008,316(1-2):28-34
Silicalite-1 micromembranes of approximately 80 μm in diameter have been prepared by synthesizing the zeolite material inside a network of perforations created by using a Nd–YAG laser on 75 μm thick stainless steel sheets. Several strategies have been introduced here to reduce the thickness of the micromembranes synthesized; among these the most successful involved using a polyamide filling to reduce the volume of the microperforations accessible to the synthesis solution. The density of microperforations could be tailored to prepare arrays of micromembranes of different overall porosity (1.8, 3.7, 6.6 and 7.7%). The micromembranes performed well in the propane/N2 separation, showing a maximum propane/N2 separation factor of 46, at a propane permeance of about 5 × 10−6 mol/(m2 s Pa). 相似文献
119.
M. S. C. S. Santos Ester F. G. Barbosa 《Journal of molecular catalysis. A, Chemical》2000,160(2):293-313
A kinetic study of the joint homogeneous–heterogeneous catalysis for the quaternization of silver (I)-coordinated triethylamine and tributilamine by ethyl iodide was performed in toluene. The data obtained substantiated the superficial molecular arrangement, previously proposed by Barbosa and Spiro, and exposed a new competitive reaction of the non-coordinated soluble silver salt with the alkyl halide in the solvent under study. Estimates of the solution rate constants were obtained for both systems and evidence of a surface effect is also presented. 相似文献
120.