排序方式: 共有48条查询结果,搜索用时 15 毫秒
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Castro Jorge Fernández Francisco Olivares Felipe Berríos Cristhian Garrido-Ramírez Elizabeth Blanco Elodie Escalona Néstor Aspée Alexis Barrías Pablo Ureta-Zañartu M. Soledad 《Journal of Solid State Electrochemistry》2021,25(1):117-131
Journal of Solid State Electrochemistry - 2,4,6-trichlorophenol (TCP) is a persistent pollutant introduced in water by industrial processes and pesticides. We have studied the electrooxidation of... 相似文献
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Excitons of polydiacetylene chains, diluted in a 3BCMU monomer single crystal, turn at very low light intensity into a nonabsorbing polariton state once the polymer concentration exceeds 10{-4} in weight. The transition is evident from a Lorentzian absorption peak which is truncated at an optical density OD approximately 2 and is consistent with polariton coupling of light to eigenstates of the solid while Rabi coupling of individual chains to light is excluded. The saturated absorption is nearly independent of polymer content and crystal thickness and defines a surface region where photons are converted into polaritons, the corresponding electromagnetic eigenmodes of matter. 相似文献
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CV Tomy D Pal SS Banerjee S Ramakrishnan AK Grover S Bhattacharya MJ Higgins G Balakrishnan McK Paul 《Pramana》2002,58(5-6):925-935
The weakly pinned single crystals of the hexagonal 2H-NbSe2 compound have emerged as prototypes for determining and characterizing the phase boundaries of the possible order-disorder
transformations in the vortex matter. We present here a status report based on the ac and dc magnetization measurements of
the peak effect phenomenon in three crystals of 2H-NbSe2, in which the critical current densities vary over two orders of magnitude. We sketch the generic vortex phase diagram of
a weakly pinned superconductor, which also utilizes theoretical proposals. We also establish the connection between the metastability
effects and pinning. 相似文献
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Eduardo González‐Olivares Lina M. Gallego‐Berrío Betsabé González‐Yañez Alejandro Rojas‐Palma 《Mathematical Methods in the Applied Sciences》2015,38(18):5183-5196
In this work, a modified Holling–Tanner predator–prey model is analyzed, considering important aspects describing the interaction such as the predator growth function is of a logistic type; a weak Allee effect acting in the prey growth function, and the functional response is of hyperbolic type. Making a change of variables and time rescaling, we obtain a polynomial differential equations system topologically equivalent to the original one in which the non‐hyperbolic equilibrium point (0,0) is an attractor for all parameter values. An important consequence of this property is the existence of a separatrix curve dividing the behavior of trajectories in the phase plane, and the system exhibits the bistability phenomenon, because the trajectories can have different ω ? limit sets; as example, the origin (0,0) or a stable limit cycle surrounding an unstable positive equilibrium point. We show that, under certain parameter conditions, a positive equilibrium may undergo saddle‐node, Hopf, and Bogdanov–Takens bifurcations; the existence of a homoclinic curve on the phase plane is also proved, which breaks in an unstable limit cycle. Some simulations to reinforce our results are also shown. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Guillet T Berréhar J Grousson R Kovensky J Lapersonne-Meyer C Schott M Voliotis V 《Physical review letters》2001,87(8):087401
The excitonic luminescence of a highly ordered single conjugated polymer chain is studied by microphotoluminescence. At T< or =10 K it consists of a single Lorentzian line. The linewidth increases linearly with T between 6 and 60 K, from 350 microeV at 6 K, indicating a pure dephasing time of approximately 2 ps. Above 10 K, other neighboring regions along the chain direction start to emit at a slightly higher (by approximately 1 meV) energy. This indicates very small inhomogeneous broadening, very long chains ( > or =10 microm), and a long range and very rapid exciton energy transfer ( >10 microm in <100 ps). 相似文献
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In subnormal glow discharge under d.c. excitation at different pressure in a varying transverse magnetic field (0 to 30 G)
some measurements have been carried out for various initial average tube currents. The voltage across the discharge increases
and average tube current and residual current decreases in the magnetic field. With the help of Beckman’s expression [4] for
the axial field and the electron density distribution in a transverse magnetic field the observed variation of current and
voltage can be satisfactorily explained. The variation of axial electric field with transverse magnetic field can be represented
to a fair degree of accuracy by the derived equation. The behaviour of residual current with magnetic field has been observed
in these oscillations. 相似文献
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An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations. 相似文献
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The aim of this note is to give short algebraic proofs of theorems of Handelman, Pólya and Schmüdgen concerning the algebraic
structure of polynomials being positive on certain subsets of ℝ
n
. The main ingredient of the proofs is the representation theorem of Kadison–Dubois. The proof of the latter is elementary
and algebraic but tricky.
Received: 6 February 1999 / Revised version: 28 August 2000 相似文献