670 research outputs found
Zonal flow generation and its feedback on turbulence production in drift wave turbulence
Plasma turbulence described by the Hasegawa-Wakatani equations has been
simulated numerically for different models and values of the adiabaticity
parameter C. It is found that for low values of C turbulence remains isotropic,
zonal flows are not generated and there is no suppression of the meridional
drift waves and of the particle transport. For high values of C, turbulence
evolves toward highly anisotropic states with a dominant contribution of the
zonal sector to the kinetic energy. This anisotropic flow leads to a decrease
of a turbulence production in the meridional sector and limits the particle
transport across the mean isopycnal surfaces. This behavior allows to consider
the Hasegawa-Wakatani equations a minimal PDE model which contains the
drift-wave/zonal-flow feedback loop prototypical of the LH transition in plasma
devices.Comment: 14 pages, 7 figure
Second generation diffusion model of interacting gravity waves on the surface of deep fluid
We propose a second generation phenomenological model for nonlinear interaction of gravity waves on the surface of deep water. This model takes into account the effects of non-locality of the original Hasselmann diffusion equation still preserving important properties of the first generation model: physically consistent scaling, adherence to conservation laws and the existence of Kolmogorov-Zakharov solutions. Numerical comparison of both models with the original Hasselmann equation shows that the second generation models improves the angular distribution in the evolving wave energy spectrum
The amplifier of unipolar pulses of the short range radar system
The amplifier of videopulses intended for work as a source of a pulse feed of the Hannah diodes 3А763А-M of the short range radar system is described. Characteristics of the amplifier are: coefficient of amplification 16 dB; the maximal amplitude of output pulses - 6 V; the maximal current in a pulse - 2,5 A
Research of high-current pulsed electron beam energy distribution in depth of sheet of water
Distribution of the absorbed doze and energy of the high-current pulsed electron beam formed by accelerator TEU-500 (350...500 kV, 60 ns, current density 0,3...0,4 kA/sm2) in water sheet depth has been measured. The high-resolution measurement technique of doze and energy distribution with application of dosimetric film based on lavsan with phenazine covering was used. Spatial resolution at registration of the absorbed doze in the range of 5...100 kGr amounts to 20...30 mkm. It was shown that at absorption of electron beam with high current density (in conditions of track overlapping on surface of the absorbing layer) distribution of the absorbed doze in thedepth within the limits of ±10 % coincides with distribution obtained for low-current bea
Second generation diffusion model of interacting gravity waves on the surface of deep fluid
International audienceWe propose a second generation phenomenological model for nonlinear interaction of gravity waves on the surface of deep water. This model takes into account the effects of non-locality of the original Hasselmann diffusion equation still preserving important properties of the first generation model: physically consistent scaling, adherence to conservation laws and the existence of Kolmogorov-Zakharov solutions. Numerical comparison of both models with the original Hasselmann equation shows that the second generation models improves the angular distribution in the evolving wave energy spectrum
Quantum quenches in fractonic field theories
We study out-of-equilibrium dynamics caused by global quantum quenches in
fractonic scalar field theories. We consider several types of quenches, in
particular, the mass quench in theories with different types of discrete
rotational symmetries ( and ), as well as an
instantaneous quench via the transition between them. We also investigate
fractonic boundary quenches, where the initial state is prepared on a
finite-width slab in Euclidean time. We find that perturbing a fractonic system
in finite volume especially highlights the restricted mobility via the
formation and subsequent evolution of specific -symmetric spatial
structures. We discuss a generalization to -symmetric field
theories, and introduce a proper regularization, which allows us to explicitly
deal with divergences inherent to fractonic field theories.Comment: v1: 21 pages, 8 figures; v2: 20 pages, 8 figures, minor correction
Mesoscopic wave turbulence
We report results of sumulation of wave turbulence. Both inverse and direct
cascades are observed. The definition of "mesoscopic turbulence" is given. This
is a regime when the number of modes in a system involved in turbulence is high
enough to qualitatively simulate most of the processes but significantly
smaller then the threshold which gives us quantitative agreement with the
statistical description, such as kinetic equation. Such a regime takes place in
numerical simulation, in essentially finite systems, etc.Comment: 5 pages, 11 figure
Genetic Predictors of Malignancy: a Literature Review
The review covers recent research on cancer as a genetic disease manifesting both sporadically and in germline through variant genomic mutations or DNA rearrangements. This change can be point mutations, chromosomal aberrations or hypermethylation leading to DNA repair failures. Defects in tumour suppressor genes (BRCA1, BRCA2, CHEK2, PTCH1, etc.) underly hereditary predisposition to breast cancer (BC) and ovarian cancer (OC) due to genome instability. Studying somatic mutations is key to the understanding of carcinogenesis mechanisms and finding apt therapies. Heterogeneity of cancers renders the tumour mutation profiling uneasy. The treatment choice and efficacy in BC and OC depends on homologous recombination defects in tumour cells usually imposed by damaged BRCA1/2 genes. CHEK2- associated neoplasms account for most hereditary BCs linked to flaws in the DNA repair machinery. Overexpression of the PTCH1 protein is the target in breast, lung, ovarian, colonic cancers, etc.Genetic research has fundamentally altered our understanding of the aetiology and pathogenesis of human malignancy. The molecular cancer phenotype is of paramount importance in the disease prognosis and treatment personalisation
- …