45,912 research outputs found
Comparisons and Applications of Four Independent Numerical Approaches for Linear Gyrokinetic Drift Modes
To help reveal the complete picture of linear kinetic drift modes, four
independent numerical approaches, based on integral equation, Euler initial
value simulation, Euler matrix eigenvalue solution and Lagrangian particle
simulation, respectively, are used to solve the linear gyrokinetic
electrostatic drift modes equation in Z-pinch with slab simplification and in
tokamak with ballooning space coordinate. We identify that these approaches can
yield the same solution with the difference smaller than 1\%, and the
discrepancies mainly come from the numerical convergence, which is the first
detailed benchmark of four independent numerical approaches for gyrokinetic
linear drift modes. Using these approaches, we find that the entropy mode and
interchange mode are on the same branch in Z-pinch, and the entropy mode can
have both electron and ion branches. And, at strong gradient, more than one
eigenstate of the ion temperature gradient mode (ITG) can be unstable and the
most unstable one can be on non-ground eigenstates. The propagation of ITGs
from ion to electron diamagnetic direction at strong gradient is also observed,
which implies that the propagation direction is not a decisive criterion for
the experimental diagnosis of turbulent mode at the edge plasmas.Comment: 12 pages, 10 figures, accept by Physics of Plasma
An exactly solvable phase transition model: generalized statistics and generalized Bose-Einstein condensation
In this paper, we present an exactly solvable phase transition model in which
the phase transition is purely statistically derived. The phase transition in
this model is a generalized Bose-Einstein condensation. The exact expression of
the thermodynamic quantity which can simultaneously describe both gas phase and
condensed phase is solved with the help of the homogeneous Riemann-Hilbert
problem, so one can judge whether there exists a phase transition and determine
the phase transition point mathematically rigorously. A generalized statistics
in which the maximum occupation numbers of different quantum states can take on
different values is introduced, as a generalization of Bose-Einstein and
Fermi-Dirac statistics.Comment: 17 pages, 2 figure
Impact of bullying on occupational commitment in young nursing professionals: the mediating role of emotional labour and emotional exhaustion
Background: Nurses are often exposed to workplace bullying, which leads to their burnout and leaving the profession. However, the processes by which workplace bullying leads to such outcomes are not clear. Aims: This study investigates how work-related and personal-related bullying affect nurses’ occupational commitment by integrating emotional labour and emotional exhaustion. Method: This study employs a cross-sectional design. The model was tested using structural equation modelling wif a sample of 245 Chinese nurses. Results: Work-related bullying is positively related to both surface acting and deep acting, and a negative relationship exists between deep acting and emotional exhaustion. Personal-related bullying is not related to either surface acting or deep acting, but is positively related to emotional exhaustion. Emotional exhaustion is negatively related to affective occupational commitment. Conclusions: This study implies that bullying behaviours should be distinguished wif work-related bullying and personal-related bullying, and emotional regulation strategies are meaningful in managing the negative impact of work-related bullying. Implication for nursing management: Policymakers and managers need to distinguish two types of bullying behaviour and manage them accordingly wif different strategies. For nursing schools it is important to prepare nursing students wif not only professional skills but also social competence and emotional management skills.info:eu-repo/semantics/acceptedVersio
Stability of an Exciton bound to an Ionized Donor in Quantum Dots
Total energy, binding energy, recombination rate (of the electron hole pair)
for an exciton (X) bound in a parabolic two dimensional quantum dot by a donor
impurity located on the z axis at a distance d from the dot plane, are
calculated by using the Hartree formalism with a recently developed numerical
method (PMM) for the solution of the Schroedinger equation. As our analysis
indicates there is a critical dot radius such that for radius less than the
critical radius the complex is unstable and with an increase of the impurity
distance this critical radius increases. Furthermore, there is a critical value
of the mass ratio such that for mass ratio less than the critical value the
complex is stable. The appearance of this stability condition depends both on
the impurity distance and the dot radius, in a way that with an increase of the
impurity distance we have an increase in the maximum dot radius where this
stability condition appears. For dot radii greater than this maximum dot radius
(for fixed impurity distance) the complex is always stable.Comment: 17 pages, 7 figures Applying a new numerical method which is based on
the adiabatic stability of quantum mechanics, we study the stability of an
exciton (X) bound in a parabolic two dimensional quantum dot by a donor
impurity located on the z axis at a distance d from the dot plan
Tunneling into Multiwalled Carbon Nanotubes: Coulomb Blockade and Fano Resonance
Tunneling spectroscopy measurements of single tunnel junctions formed between
multiwalled carbon nanotubes (MWNTs) and a normal metal are reported. Intrinsic
Coulomb interactions in the MWNTs give rise to a strong zero-bias suppression
of a tunneling density of states (TDOS) that can be fitted numerically to the
environmental quantum-fluctuation (EQF) theory. An asymmetric conductance
anomaly near zero bias is found at low temperatures and interpreted as Fano
resonance in the strong tunneling regime.Comment: 4 pages, 4 figure
Regions of significant influence on unforced global mean surface air temperature variability in climate models
We document the geographic regions where local variability is most associated with unforced global mean surface air temperature (GMT) variability in Coupled Model Intercomparison Project Phase 5 coupled global climate models (GCMs) at both the subdecadal and interdecadal timescales. For this purpose, Regions of Significant Influence on GMT are defined as locations that have a statistically significant correlation between local surface air temperature (SAT) and GMT (with a regression slope greater than 1), and where local SAT variation leads GMT variation in time. In both GCMs and observations, subdecadal timescale GMT variability is most associated with SAT variation over the eastern equatorial Pacific. At the interdecadal timescale, GMT variability is also linked with SAT variation over the Pacific in many GCMs, but the particular spatial patterns are GCM dependent, and several GCMs indicate a primary association between GMT and SAT over the Southern Ocean. We find that it is difficult to validate GCM behavior at the interdecadal timescale because the pattern derived from observations is highly depended on the method used to remove the forced variability from the record. The magnitude of observed GMT variability is near the ensemble median at the subdecadal timescale but well above the median at the interdecadal timescale. GCMs with a stronger subdecadal relationship between GMT and SAT over the Pacific tend to have more variable subdecadal GMT while GCMs with a stronger interdecadal relationship between GMT and SAT over parts of the Southern Ocean tend to have more variable GMT
- …