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11.
We establish new estimates for the Laplacian, the div–curl system, and more general Hodge systems in arbitrary dimension, with an application to minimizers of the Ginzburg–Landau energy. To cite this article: J. Bourgain, H. Brezis, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
12.
Herve Loïc 《Integral Equations and Operator Theory》1998,32(2):199-215
LetX be a locally compact space, andT, a quasi-compact positive operator onC
0(X), with positive spectral radius,r. Then the peripheral spectrum ofT is a finite set of poles containingr, and the residue of the resolvent ofT at each peripheral pole is of finite rank. Using the concept of closed absorbing set, we develop an iterative process that gives the order,p, ofr, some special bases of the algebraic eigenspaces ker(T-r)
p
and ker(T
*-r)
p
, and finally the dimension of the algebraic eigenspace associated to each peripheral pole. 相似文献
13.
14.
A series of P[N-isopropylacrylamide (NIPAM)] latexes with different contents of cyano groups were successfully prepared by either seeded
or shot-growth polymerizations of an aqueous solution containing acrylonitrile (AN) onto a seed P[NIPAM] latex, respectively, and further characterized by FT-IR, 1H-NMR, elemental analysis, as well as by quasielastic light scattering (QELS) and scanning electron microscopy (SEM). All
prepared surface-cyanofunctionalized P[NIPAM] latexes exhibited the same range of lower critical solution temperature (LCST) as a pure P[NIPAM] latex. The shot polymerization process proved more efficient at yielding cyano derivatized latexes than the seeded
polymerization technique. The amount of incorporated cyano groups onto the particles was determined with a good correlation
both by 1H-NMR and elemental analysis. The higher the amount of initially introduced AN monomer in the reaction mixture, the more cyano
groups were incorporated onto the particles. The surface of the particles with high content of cyano groups appeared quite
rough by SEM in comparison with that of the pure P[NIPAM] particles.
Received: 25 February 1998 Accepted: 23 June 1998 相似文献
15.
Michelini Mdel C Russo N Alikhani ME Silvi B 《Journal of computational chemistry》2004,25(13):1647-1655
The Density functional theory has been applied to characterize the structural features of Mo(1,2)-NH(3),-C(2)H(4), and -C(2)H(2) compounds. Coordination modes, geometrical structures, and binding energies have been calculated for several spin multiplets. It has been shown that in contrast to the conserved spin cases (Mo(1,2)-NH(3)), the interaction between Mo (or Mo(2)) and C(2)H(4) (or C(2)H(2)) are the low-spin (Mo-C(2)H(4) and -C(2)H(2)) and high-spin (Mo(2)-C(2)H(4) and -C(2)H(2)) complexes. In the ground state of Mo(1,2)-C(2)H(4) and -C(2)H(2), the metal-center always reacts with the C-C center. The spontaneous formation of the global minima is found to be possible due to the crossing between the potential energy surfaces (ground and excited states with respect to the metallic center). The bonding characterization has been performed using the topological analysis of the Electron Localization Function. It has been shown that the most stable electronic structure for a pi-acceptor ligand correlates with a maximum charge transfer from the metal center to the C-C bond of the unsaturated hydrocarbons, resulting in the formation of two new basins located on the carbon atoms (away from hydrogen atoms) and the reduction of the number of attractors of the C-C basin. The interaction between Mo(1,2) and C(2)H(4) (or C(2)H(2)) should be considered as a chemical reaction, which causes the multiplicity change. Contrarily, there is no charge transfer between Mo(1,2) and NH(3), and the partners are bound by an electrostatic interaction. 相似文献
16.
Optical sensors based on hybrid DNA/conjugated polymer complexes 总被引:2,自引:0,他引:2
Ho HA Béra-Abérem M Leclerc M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(6):1718-1724
Single-stranded DNA (ss-DNA) can specifically bind to various targets, including a complementary ss-DNA, ions, proteins, drugs, and so forth. When binding takes place, the oligonucleotide probe often undergoes a conformational transition. This conformational change of the negatively charged ss-DNA can be detected by using a water-soluble, cationic polythiophene derivative, which transduces the complex formation into an optical (colorimetric or fluorometric) signal without any labeling of the probe or the target. This simple and rapid methodology has enabled the specific and sensitive detection of nucleic acids and human thrombin. This new biophotonic tool can easily be applied to the detection of various other biomolecules and is also useful in the high-throughput screening of new drugs. 相似文献
17.
This review presents the recent advances in the achievement of organized proteo-lipidic nanostructures based on Langmuir-Blodgett technology and their potential applications in the nanobioscience area. By using the self-assembled properties of amphiphilic biomolecules at the air-water interface, the Langmuir-Blodgett (LB) technique offers the possibility to prepare ultrathin layers suitable for biomolecule immobilization at the molecular level. This review will provide a general overview of the enzyme association with preformed Langmuir-Blodgett films in connection with their potential applications in biosensing device developments, and then introduce the design of a new functionalised biomimetic nanostructure with oriented recognition site. The potential applications of such an organized proteo-lipidic nanostructure for biocatalysis investigations of an immobilised enzyme in a biomimetic situation and for the development of bioelectronic devices are finally discussed. 相似文献
18.
Margarita Valero Brígida Esteban Rafael Peläez Licesio J. Rodrïguez 《Journal of inclusion phenomena and macrocyclic chemistry》2004,48(3-4):157-163
The aim of the present study was to investigate the effect of the presence of thewater-soluble polymer polyvinylpyrrolidone (PVP) MW = 24000 g/mol, on thecomplexation of the phototoxic anti-inflammatory drug naproxen, in its sodiumsalt form, with hydroxypropil-β-cyclodextrin (HP-β-CD). The datashown that the polymer interacts with the free naproxen and with thenaproxen:HP-β-CD inclusion complex. The presence of different proportions of PVP, in the 0–1%(w/w) rangesystematically increased the Kapp of the naproxen:HP-β-CD inclusioncomplex formation. The cause of this increase is that the polymer interactswith the HP-β-CD with a binding constant of K2 = 29000 ± 53 M-1; and with the naproxen:HP-β-CD inclusion complex, to givea ternary complex naproxen:HP-β-CD:PVP. The binding constant of thisprocess was K3 = 5350 ± 1 M-1. NMR data revealed that in the ternary system, PVP is outside of the cyclodextrin, and therefore must be wholly or partially recovering the naproxen:HP-β-CD inclusion complex. 相似文献
19.
N. Bélaïd-Drira H. Zamali M. Jemal 《Journal of Thermal Analysis and Calorimetry》1996,46(5):1449-1458
Phase diagram of the binary system LiNO3-NaNO3 has been obtained by using direct and differential thermal analysis between 323 and 623 K. This system is characterized by an eutectic plateau at 467 K. The eutectic point is at 0.465 mole NaNO3. A peritectic appears at 550 K. There is no miscibility in the solid state. These findings associated with some other thermodynamic results have been used to calculate the activities of the constituents along the liquids curve and the excess thermodynamic functions at 618 K. The constituents seem not to have a symmetrical influence on the thermodynamic quantities. 相似文献
20.
A number of α-β acetylenic carbinols RFCCC(OH)RR′, in which the acetylenic proton was substituted by a F-alkyl group, were first prepared, from a classical reaction of (F-alkynyl)- lithium derivatives RFCCLi upon various carbonyl compounds.On another hand, the reaction of propargyl bromide metallic complexes (organoaluminic, or ultrasonic irradiation activated organozinc) upon some polyfluorinated ketones RFCOR led to the formation, in convenient yields, of the propargylic carbinols HCCCH2C(OH)RRF.The synthesis and properties of these series of new (F-alkyl) substituted acetylenic and propargylic alcohols are described and discussed. 相似文献