3,293 research outputs found
Integral equations for three-body Coulombic resonances
We propose a novel method for calculating resonances in three-body Coulombic
systems. The method is based on the solution of the set of Faddeev and
Lippmann-Schwinger integral equations, which are designed for solving the
three-body Coulomb problem. The resonances of the three-body system are defined
as the complex-energy solutions of the homogeneous Faddeev integral equations.
We show how the kernels of the integral equations should be continued
analytically in order that we get resonances. As a numerical illustration a toy
model for the three- system is solved.Comment: 9 pages, 1 EPS figur
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Unraveling the Cationic and Anionic Redox Reactions in a Conventional Layered Oxide Cathode
Increasing interest in high-energy lithium-ion batteries has triggered the demand to clarify the reaction mechanism in battery cathodes during high-potential operation. However, the reaction mechanism often involves both transition-metal and oxygen activities that remain elusive. Here we report a comprehensive study of both cationic and anionic redox mechanisms of LiNiO2 nearly full delithiation. Selection of pure LiNiO2 removes the complication of multiple transition metals. Using combined X-ray absorption spectroscopy, resonant inelastic X-ray scattering, and operando differential electrochemical mass spectrometry, we are able to clarify the redox reactions of transition metals in the bulk and at the surface, reversible lattice oxygen redox, and irreversible oxygen release associated with surface reactions. Many findings presented here bring attention to different types of oxygen activities and metal-oxygen interactions in layered oxides, which are of crucial importance to the advancement of a Ni-rich layered oxide cathode for high capacity and long cycling performance
Készülőben az új Európai Moha Vörös Könyv = The new Red Data Book of European Bryophytes in preparation
The new Red Data Book of European Bryophytes is the most important recent project of the European Committee for Conservation of Bryophytes, and the basis of bryophyte conservation in most European countries. The first edition, published in 1995, is now in urgent need of updating.
Since its publication, our knowledge of the bryophytes of Europe has been considerably improved, especially concerning taxonomy and distribution. The work has started: a comprehensive table, listing the occurrence and Red List status of each species, in each European country, has been prepared.
A short list of candidate species for IUCN threat assessment was established by eliminating species known with certainty to be of least concern. Of 2140 bryophyte species known to occur in Europe, 241 liverworts and 721 mosses were selected for further consideration. Among them, 28 liverworts and 98 mosses occur in Hungary. Examples of some species occurring in Hungary are presented below to show which criteria are used to select species for the European candidate list. With 12 fi gures
Faddeev approach to confined three-quark problems
We propose a method that allows for the efficient solution of the three-body
Faddeev equations in the presence of infinitely rising confinement
interactions. Such a method is useful in calculations of nonrelativistic and
especially semirelativistic constituent quark models. The convergence of the
partial wave series is accelerated and possible spurious contributions in the
Faddeev components are avoided. We demonstrate how the method works with the
example of the Goldstone-boson-exchange chiral quark model for baryons.Comment: 6 page
A microrod-resonator Brillouin laser with 240 Hz absolute linewidth
We demonstrate an ultralow-noise microrod-resonator based laser that
oscillates on the gain supplied by the stimulated Brillouin scattering optical
nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding
frequency noise floor, which is limited by fundamental thermal fluctuations.
Here, we show experimental evidence that thermal effects also dominate the
close-to-carrier frequency fluctuations. The 6-mm diameter microrod resonator
used in our experiments has a large optical mode area of ~100 {\mu}m, and
hence its 10 ms thermal time constant filters the close-to-carrier optical
frequency noise. The result is an absolute laser linewidth of 240 Hz with a
corresponding white-frequency noise floor of 0.1 Hz/Hz. We explain the
steady-state performance of this laser by measurements of its operation state
and of its mode detuning and lineshape. Our results highlight a mechanism for
noise that is common to many microresonator devices due to the inherent
coupling between intracavity power and mode frequency. We demonstrate the
ability to reduce this noise through a feedback loop that stabilizes the
intracavity power.Comment: 11 pages, 5 figure
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