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171.
Miguel Herrero Elena Ibáñez Alejandro Cifuentes Jose Bernal 《Journal of chromatography. A》2009,1216(43):7110-7129
In this work, the main developments and applications of multidimensional chromatographic techniques in food analysis are reviewed. Different aspects related to the existing couplings involving chromatographic techniques are examined. These couplings include multidimensional GC, multidimensional LC, multidimensional SFC as well as all their possible combinations. Main advantages and drawbacks of each coupling are critically discussed and their key applications in food analysis described. 相似文献
172.
Marcela Hurtado Dr. Manuel Yánez Prof. Dr. Rebeca Herrero Andrés Guerrero Juan Z. Dávalos Dr. José‐Luis M. Abboud Prof. Dr. Brahim Khater Dr. Jean‐Claude Guillemin Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(18):4622-4629
The acidity‐enhancing effect of BH3 in gas‐phase phosphine ? boranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas‐phase acidities (GA) of MePH2 and MePH2 ? BH3 differ by about 118 kJ mol?1 (see picture).
173.
174.
Design of Assembled Systems Based on Conjugated Polyphenylene Derivatives and Carbon Nanohorns 下载免费PDF全文
Daniel Iglesias Dr. Javier Guerra Dr. M. Victoria Gómez Dr. Antonio M. Rodríguez Dr. Pilar Prieto Dr. Ester Vázquez Dr. M. Antonia Herrero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11643-11651
Promising materials have been designed and fully characterised by an effective interaction between versatile platforms such as carbon nanohorns (CNHs) and conjugated molecules based on thiophene derivatives. Easy and non‐aggressive methods have been described for the synthesis and purification of the final systems. Oligothiophenephenylvinylene (OTP) systems with different geometries and electron density are coupled to the CNHs. A wide range of characterization techniques have been used to confirm the effective interaction between the donor (OTP) and the acceptor (CNH) systems. These hybrid materials show potential for integration into solar cell devices. Importantly, surface‐enhanced Raman spectroscopy (SERS) effects are observed without the presence of any metal surface in the system. Theoretical calculations have been performed to study the optimised geometries of the noncovalent interaction between the surface and the organic molecule. The calculations allow information on the monoelectronic energies of HOMO–LUMO orbitals and band gap of different donor systems to be extracted. 相似文献
175.
Miguel A. Herrero Andrew A. Lacey Juan J. L. Velázquez 《Archive for Rational Mechanics and Analysis》1998,142(3):219-251
The pair of parabolic equations , , with a>0 and b>0 models the temperature and concentration for an exothermic chemical reaction for which just one species controls the reaction
rate f. Of particular interest is the case where , which appears in the Frank‐Kamenetskii approximation to Arrhenius‐type reactions. We show here that for a large choice of
the nonlinearity f(u,v) in (1), (2)(including the model case (3)), the corresponding initial‐value problem for (1), (2) in the whole space with
bounded initial data has a solution which exists for all times. Finite‐time blow‐up might occur, though, for other choices
of function f(u,v), and we discuss here a linear example which strongly hints at such behaviour.
(Accepted September 16, 1996) 相似文献
176.
F. Boixader J. Farjas R. Herrero G. Orriols J. Massaneda F. Pi J. I. Rosell 《Fiber and Integrated Optics》1993,12(3):287-300
We consider nonlinear interferometric devices based on opto-thermal bistability with localized absorption and show how the introduction of composite structures within the interferometer makes feasible its setting and resetting between stable outputs by applying positive light pulses on different parts of the bistable device. Experimental demonstration of all-optical flip-flop operation is reported for two interferometric configurations, one of them being extremely simple and well suited for parallel processing. 相似文献
177.
H. Herrero J. Millán Rodríguez C. Pérez-García 《Zeitschrift für Physik B Condensed Matter》1995,99(1):457-463
The amplitude equation for a convective system under a vertical magnetic field is derived. The coefficients in these equations
have been numerically calculated for infinite Prandtl number fluids and for boundary conditions both free and rigid top and
bottom. The results confirm that, for realistic parameter values only stationary convection can be present and the pattern
is made by convective rolls. 相似文献
178.
Domingo A. Herrero 《Integral Equations and Operator Theory》1987,10(2):297-303
The title refers to an empty class of operators. Moreover, if T is a triangular Banach space operator, then either T is algebraic and the double commutant has infinite strict multiplicity, or T is not algebraic and the commutant has infinite strict multiplicity. A rationally strictly cyclic, but not strictly cyclic, operator cannot have finite strict multiplicity.This research was partially supported by a Grant of the National Science Foundation. 相似文献
179.
We calculate the QCD evolution equations for structure functions with supersymmetric particles excited for the following models: light gluinos, g? and heavy squarks q? with ; light squarks, and heavy gluinos with . The momentum sum rules and the behaviour of structure functions as x → 1 are particularly discussed. 相似文献
180.
In this work, an exhaustive survey of capillary electromigration methods used to analyze natural antioxidants is presented together with some discussion of the use of these substances use as functional foods. This review provides an updated and exhaustive overview of the separation and identification by capillary electrophoresis of natural compounds with antioxidant activity found in natural matrices and/or foods. The compounds concerned are catechins, isoflavones, anthocyanins, phenolic acids, vitamins, as well as other less common natural substances that have shown antioxidant activity. 相似文献