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751.
752.
753.
We present a system for the electrocoalescence of microfluidic droplets immersed in an immiscible solvent, where the undeformed droplet diameters are comparable to the channel diameter. The electrodes are not in direct contact with the carrier liquid or the droplets, thereby minimizing the risk of cross-contamination between different coalescence events. Results are presented for the coalescence of buffered aqueous droplets in both quiescent and flowing fluorocarbon streams, and on-flight coalescence is demonstrated. The capillary-based system presented here is readily amenable to further miniaturization to any lab-on-a-chip application where the conductivity of the droplets is much greater than the conductivity of the stream containing them, and should aid in the further application of droplet microreactors to biological analyses. 相似文献
754.
Pilar Cabildo Rosa Claramunt Jos Luis Lavandera Dionisia Sanz Jose Elguero Christine Enjalbal Jean-Louis Aubagnac 《Journal of heterocyclic chemistry》1997,34(2):367-374
Significant information on the structure of various bisazolium salts of the type CA2 (C++ 2A?) were revealed by the study of the FAB spectra of their positive and negative ions. Thus only one spectrum, whatever it consists of the positive or of the negative ions spectrum, enables the identification of the cation C++ and of the anion A?. Moreover, the same information are collected from the CAD spectrum of the adduct ion CA+ allowing the identification of such a compound in a mixture. 相似文献
755.
Bruce H. Robinson Jean-Louis Monge Lauraine A. Dalton Larry R. Dalton Alvin L. Kwiram 《Chemical physics letters》1974,28(2):169-175
The nonlinear response of spin systems to intense radiation fields is quantitatively treated by a modification of the stochastic Liouville equation for the spin density matrix. In particular, applied modulation terms are included in this equation. The resulting formalism provides a general method for calculating nonlinear spin response for dilute systems of radicals in a high magnetic field. In this communication, frequency and field swept absorption and dispersion electron-electron double resonance spectra are calculated and compared with experimental spectra recorded under conditions of sinusoidal magnetic field modulation and phase-sensitive detection. Good reproduction of the detailed lineshapes of experimental spectra is observed in all cases. The dependence of ELDOR reduction factors upon modulation frequency is discussed. A theoretical analysis such as employed in the present communication is shown to be essential if ELDOR reduction factors are to be related to relaxation times and hence to molecular dynamics, and if the design of ELDOR experiments is to be optimized. 相似文献
756.
757.
Claude Bohnke Jean-Louis Fourquet Nirina Randrianantoandro Thierry Brousse Olivier Crosnier 《Journal of Solid State Electrochemistry》2002,6(6):403-411
The effect of a milling process on the electrochemical performance of Li2Ti3O7 electrodes has been investigated by the galvanostatic intermittent titration technique (GITT) and AC impedance spectroscopy.
The insertion ratio is slightly increased by the milling treatment and a value of x
Li=1.25 per mol Li2Ti3O7 has been determined. The average potential during insertion is close to 1.5 V/Li. The analysis of impedance data obtained
at equilibrium during insertion and deinsertion shows two relaxation processes and a diffusion phenomenon at low frequency
according to the Frumkin-Melik-Gayakazian model. Cycling experiments of batteries using this material were performed with
unmilled and milled particles. Composite electrodes containing different amounts of electroactive material added to a binder
and a conductive additive have also been prepared in order to check the effect of grinding on the cyclability of the compound.
Interesting electrochemical performances have been determined with such electrodes: lithium uptake up to 1.25 Li per Li2Ti3O7, low irreversible capacity loss between the first and the following cycles, good stability upon cycling even after 50 cycles.
However, the milled process has not improved significantly the electrochemical performance of the Li2Ti3O7 electrodes.
Electronic Publication 相似文献
758.
Jean-Louis Pierre Paul Baret Eve-Marie Rivoirard 《Journal of heterocyclic chemistry》1978,15(5):817-823
Aziridines bearing a functionnality on a ring carbon have been treated with methyl fluorosulfonate to afford the corresponding aziridinium salts in high yields. These compounds were unambiguously characterised by the ring opening reactions using lithium chloride. Two quantitative methods for effecting counter-ion exchange are described. 相似文献
759.
Experimental solubilities of amorphous silica in several aqueous electrolyte solutions and in aqueous solutions of organic compounds, and theoretical considerations concerning cavity formation, electrostriction collapse, ion solvation, and long- and short-range interaction of the solvated ions with one another(1) permit the calculation of the partial excess free energies and the activity coefficients of aqueous silica. It is shown that, in the case of non-dissociated aqueous organic solutions, the variation of log m (SiO2) with the reciprocal of the dielectric constant of the solution is described by a single linear equation independent of the nature of the organic compound. For aqueous electrolyte solutions, a specific linear relationship between log m (SiO2) and the reciprocal of the dielectric constant occurs for each electrolyte. The success of the equation in reproducing the experimental solubilities of amorphous silica in aqueous solutions of electrolytes and organic compounds supports previous evidence indicating a polar charge distribution in the solvated SiO2 molecule. Our data permit the calculation of the effective local charge of dissolved SiO2 molecules and of the short-range interaction parameters between SiO2 and various ions. The proposed equation of state can be used to calculate the affinity of reactions among SiO2 minerals and complex aqueous solutions. 相似文献
760.
Thomas M Guillaume D Fourrey JL Clivio P 《Journal of the American Chemical Society》2002,124(11):2400-2401
Pyrimidine (6-4) pyrimidone photoproducts represent one of the major mutagenic and carcinogenic class of DNA damage produced by UV exposure. At present, besides their conversion to their Dewar valence isomer, (6-4) photoproducts are generally believed to be photostable, and the observed biological properties of Paterno-Büchi-derived photoproducts are, thus far, exclusively attributed to these two types of compounds. Using a model system (2) relevant to DNA photochemistry, we have observed that the 5'-base moiety of the (6-4) thymine dimer 3, under far-UV radiation, is able to undergo a ring contraction leading to a 2-oxoimidazoline, 1. This unprecedented secondary photochemical reaction constitutes the first report of a major photomodification affecting (6-4) photoproducts and strongly questions the biological stability of the (6-4) adducts under UV light with 2-imidazolone (5-4) pyrimidone adducts being possibly another source of endogenous DNA damage. 相似文献