3,137 research outputs found
Resonant coupling between localized plasmons and anisotropic molecular coatings in ellipsoidal metal nanoparticles
We present an analytic theory for the optical properties of ellipsoidal
plasmonic particles covered by anisotropic molecular layers. The theory is
applied to the case of a prolate spheroid covered by chromophores oriented
parallel and perpendicular to the metal surface. For the case that the
molecular layer resonance frequency is close to being degenerate with one of
the particle plasmon resonances strong hybridization between the two resonances
occur. Approximate analytic expressions for the hybridized resonance
frequencies, their extinction cross section peak heights and widths are
derived. The strength of the molecular - plasmon interaction is found to be
strongly dependent on molecular orientation and suggest that this sensitivity
could be the basis for novel nanoparticle based bio/chemo-sensing applications.Comment: 11 pages, 5 figure
Dimensional crossover for the beyond-mean-field correction in Bose gases
We present a detailed beyond-mean-field analysis of a weakly interacting Bose
gas in the crossover from three to low dimensions. We find an analytical
solution for the energy and provide a clear qualitative picture of the
crossover in the case of a box potential with periodic boundary conditions. We
show that the leading contribution of the confinement-induced resonance is of
beyond-mean-field order and calculate the leading corrections in the three- and
low-dimensional limits. We also characterize the crossover for harmonic
potentials in a model system with particularly chosen short- and long-range
interactions and show the limitations of the local-density approximation. Our
analysis is applicable to Bose-Bose mixtures and gives a starting point for
developing the beyond-mean-field theory in inhomogeneous systems with
long-range interactions such as dipolar particles or Rydberg-dressed atoms.Comment: 5 pages and supplemental material, revised treatment of the harmonic
confinemen
Маркшейдерське забезпечення робіт при створенні програмного модуля розкритих, підготовлених і готових до видобування балансово-промислових запасів
Розглянуто і досліджено методи визначення і нормування балансово-промислових запасів за ступенем підготовленості до видобування, які призначені для залізорудних корисних копалин і вугілля. Для багатьох видів твердих корисних копалин такі методи не розроблені. Встановлено, що кожний із видів мінеральної сировини має особливості природно-просторового розміщення у надрах, гірничо-технологічні стадії видобутку і переробки, які
враховують при підземному способі видобутку, методи визначення стану і рухомості, обліку і нормування підготовленості балансово-промислових запасів за програмним модулем
In--out intermittency in PDE and ODE models
We find concrete evidence for a recently discovered form of intermittency,
referred to as in--out intermittency, in both PDE and ODE models of mean field
dynamos. This type of intermittency (introduced in Ashwin et al 1999) occurs in
systems with invariant submanifolds and, as opposed to on--off intermittency
which can also occur in skew product systems, it requires an absence of skew
product structure. By this we mean that the dynamics on the attractor
intermittent to the invariant manifold cannot be expressed simply as the
dynamics on the invariant subspace forcing the transverse dynamics; the
transverse dynamics will alter that tangential to the invariant subspace when
one is far enough away from the invariant manifold.
Since general systems with invariant submanifolds are not likely to have skew
product structure, this type of behaviour may be of physical relevance in a
variety of dynamical settings.
The models employed here to demonstrate in--out intermittency are
axisymmetric mean--field dynamo models which are often used to study the
observed large scale magnetic variability in the Sun and solar-type stars. The
occurrence of this type of intermittency in such models may be of interest in
understanding some aspects of such variabilities.Comment: To be published in Chaos, June 2001, also available at
http://www.eurico.web.co
Empirical macromodels under test: a comparative simulation study of the employment effects of a revenue neutral cut in social security contributions
In the paper we simulate a revenue-neutral cut in the social security contribution rate using five different types of macro- / microeconomic models, namely two models based on time-series data where the labour market is modelled basically demand oriented, two models of the class of computable equilibrium models which are supply oriented and finally a firm specific model for international tax burden comparisons. Our primary interest is in the employment effects the models predict due to the cut in the contribution rate. It turns out that qualitatively all models considered predict an increase in employment three years after the cut. But the employment effects differ considerably in magnitude, which follows immediately from the different behavioral assumptions underlying the different models. -- In dem Beitrag wird der Beschäftigungseffekt infolge einer aufkommensneutralen Senkung der Sozialversicherungsbeiträge simuliert. Zu diesem Zweck werden fünf unterschiedliche ökonomische Modelle verwendet, namentlich zwei Modelle, die auf Zeitreihendaten aufbauen und in denen der Arbeitsmarkt überwiegend von der Nachfrageseite dominiert wird, zwei Modelle aus der Klasse der computable equilibrium models, die typischerweise angebotsorientiert sind, und ein mikroökonomisches, firmenspezifisches Steuerbelastungsvergleichsmodell. Alle Simulationsergebnisse der Modelle weisen auf einen, wenngleich teilweise kleinen, positiven Beschäftigungseffekt hin, der sich allerdings beträchtlich in seiner Größenordnung unterscheidet. Dies ist eine unmittelbare Folge aus den unterschiedlichen Verhaltensannahmen, die den einzelnen Modellen unterliegen.
Impact of Natural Blind Spot Location on Perimetry.
We study the spatial distribution of natural blind spot location (NBSL) and its impact on perimetry. Pattern deviation (PD) values of 11,449 reliable visual fields (VFs) that are defined as clinically unaffected based on summary indices were extracted from 11,449 glaucoma patients. We modeled NBSL distribution using a two-dimensional non-linear regression approach and correlated NBSL with spherical equivalent (SE). Additionally, we compared PD values of groups with longer and shorter distances than median, and larger and smaller angles than median between NBSL and fixation. Mean and standard deviation of horizontal and vertical NBSL were 14.33° ± 1.37° and -2.06° ± 1.27°, respectively. SE decreased with increasing NBSL (correlation: r = -0.14, p \u3c 0.001). For NBSL distances longer than median distance (14.32°), average PD values decreased in the upper central (average difference for significant points (ADSP): -0.18 dB) and increased in the lower nasal VF region (ADSP: 0.14 dB). For angles in the direction of upper hemifield relative to the median angle (-8.13°), PD values decreased in lower nasal (ADSP: -0.11 dB) and increased in upper temporal VF areas (ADSP: 0.19 dB). In conclusion, we demonstrate that NBSL has a systematic effect on the spatial distribution of VF sensitivity
Theory of semiconductor quantum-wire based single- and two-qubit gates
A GaAs/AlGaAs based two-qubit quantum device that allows the controlled
generation and straightforward detection of entanglement by measuring a
stationary current-voltage characteristic is proposed. We have developed a
two-particle Green's function method of open systems and calculate the
properties of three-dimensional interacting entangled systems
non-perturbatively. We present concrete device designs and detailed, charge
self-consistent predictions. One of the qubits is an all-electric Mach-Zehnder
interferometer that consists of two electrostatically defined quantum wires
with coupling windows, whereas the second qubit is an electrostatically defined
double quantum dot located in a second two-dimensional electron gas beneath the
quantum wires. We find that the entanglement of the device can be controlled
externally by tuning the tunneling coupling between the two quantum dots.Comment: 16 pages, 13 figures, RevTex4 two-column format, to appear in Phys.
Rev.
Enantiomerically Pure Tetravalent Neptunium Amidinates: Synthesis and Characterization
The synthesis of a tetravalent neptunium amidinate [NpCl((S )‐PEBA)] (1 ) ((S )‐PEBA=(S ,S )‐N ,N′‐bis‐(1‐phenylethyl)‐benzamidinate) is reported. This complex represents the first structurally characterized enantiopure transuranic compound. Reactivity studies with halide/pseudohalides yielding [NpX((S )‐PEBA)] (X=F (2 ), Br (3 ), N3 (4 )) have shown that the chirality‐at‐metal is preserved for all compounds in the solid state. Furthermore, they represent an unprecedented example of a structurally characterized metal–organic Np complex featuring a Np−Br (3 ) bond. In addition, 4 is the only reported tetravalent transuranic azide. All compounds were additionally characterized in solution using para‐magnetic NMR spectroscopy showing an expected C‐symmetry at low temperatures
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