On "the authentic damping mechanism" of the phonon damping model

Some general features of the phonon damping model are presented. It is concluded that the fits performed within this model have no physical content

Describing and Processing Topology and Quality of Service Parameters of Applications in the Cloud

Typical cloud applications require high-level policy driven orchestration to achieve efficient resource utilisation and robust security to support different types of users and user scenarios. However, the efficient and secure utilisation of cloud resources to run applications is not trivial. Although there have been several efforts to support the coordinated deployment, and to a smaller extent the run-time orchestration of applications in the Cloud, no comprehensive solution has emerged until now that successfully leverages applications in an efficient, secure and seamless way. One of the major challenges is how to specify and manage Quality of Service (QoS) properties governing cloud applications. The solution to address these challenges could be a generic and pluggable framework that supports the optimal and secure deployment and run-time orchestration of applications in the Cloud. A specific aspect of such a cloud orchestration framework is the need to describe complex applications incorporating several services. These application descriptions must specify both the structure of the application and its QoS parameters, such as desired performance, economic viability and security. This paper proposes a cloud technology agnostic approach to application descriptions based on existing standards and describes how these application descriptions can be processed to manage applications in the Cloud

Local harmonic approaches with approximate cranking operators

Methods of large amplitude collective motion in the adiabatic limit are examined with a special emphasis on conservation laws. We show that the restriction to point transformations, which is a usual assumption of the adiabatic time-dependent mean-field theory, needs to be lifted. In order to facilitate the application of large amplitude collective motion techniques, we examine the possibility of representing the RPA normal-mode coordinates by linear combinations of a limited number of one-body operators. We study the pairing-plus-quadrupole model of Baranger and Kumar as an example, and find that such representations exist in terms of operators that are state-dependent in a characteristic manner

Relativistic Coulomb Sum Rules for (e,e′)(e,e^\prime)

A Coulomb sum rule is derived for the response of nuclei to $(e,e^\prime)$ scattering with large three-momentum transfers. Unlike the nonrelativistic formulation, the relativistic Coulomb sum is restricted to spacelike four-momenta for the most direct connection with experiments; an immediate consequence is that excitations involving antinucleons, e.g., $N{\bar N}$ pair production, are approximately eliminated from the sum rule. Relativistic recoil and Fermi motion of target nucleons are correctly incorporated. The sum rule decomposes into one- and two-body parts, with correlation information in the second. The one-body part requires information on the nucleon momentum distribution function, which is incorporated by a moment expansion method. The sum rule given through the second moment (RCSR-II) is tested in the Fermi gas model, and is shown to be sufficiently accurate for applications to data.Comment: 32 pages (LaTeX), 4 postscript figures available from the author

Laser induced electron diffraction: a tool for molecular orbital imaging

We explore the laser-induced ionization dynamics of N2 and CO2 molecules subjected to a few-cycle, linearly polarized, 800\,nm laser pulse using effective two-dimensional single active electron time-dependent quantum simulations. We show that the electron recollision process taking place after an initial tunnel ionization stage results in quantum interference patterns in the energy resolved photo-electron signals. If the molecule is initially aligned perpendicular to the field polarization, the position and relative heights of the associated fringes can be related to the molecular geometrical and orbital structure, using a simple inversion algorithm which takes into account the symmetry of the initial molecular orbital from which the ionized electron is produced. We show that it is possible to extract inter-atomic distances in the molecule from an averaged photon-electron signal with an accuracy of a few percents

Dynamic Response of a Hypersonic Rocket Sled Considering Friction and Wear

The dynamic response of a hypersonic rocket sled was studied by considering the time-varying friction coefficient and the gap caused by wear between the slipper and track. A multibody dynamic model for a hypersonic rocket sled system was established by considering the time-varying mass and moment of inertia, nonlinear aerodynamic loads, engine thrust, track irregularity, and nonlinear contact force. As for the wear calculation, the ductile and shear criteria were used as the material damage criteria, and slipper wear was determined by the number of damaged elements. A rocket sled test was also carried out, and the dynamic response of the sled was measured. The results showed that the computational sliding displacement and velocity of the third-stage sled matched well with the test values. The computational root mean square (RMS) values of the vertical acceleration of the third-stage sled front slipper considering friction and wear matched better with the test values than with the case without considering friction and wear, which underestimated the RMS value by approximately 20.1% at Mach 5. The importance of considering friction and wear and the correctness of the computational method were validated. It is also found that the kinetic friction coefficient decreased with an increase in the product of the pressure and velocity. The wear height of the slipper increased almost linearly with the sliding displacement. The test results showed that the vertical acceleration power spectral density of the third-stage sled front slipper increased with time in the full frequency band below 2000 Hz. This study will guide the design and optimization of hypersonic rocket sleds

Structural properties and variable-range hopping conductivity of Cu₂SnS₃

In the present work, we investigated the elemental composition, structural and electrical properties of Cu₂SnS₃ (CTS) ternary semiconductor synthesized by the pyrolytic decomposition of the precursors in vacuu