Preparation, structure and superconductivity of high T(c) compounds: Research of high temperature superconductors in Hungary

In this paper the main directions, methods and results of the investigation of high-T(c) superconductors in Hungary are briefly summarized. The fundamental idea of this research is to study the effect of starting conditions on the microstructure of samples and the influence of the latter one on their superconducting parameters. The investigation concerning technical development is also mentioned

Reggeon Interactions in Perturbative QCD

We study the pairwise interaction of reggeized gluons and quarks in the Regge limit of perturbative QCD. The interactions are represented as integral kernels in the transverse momentum space and as operators in the impact parameter space. We observe conformal symmetry and holomorphic factorization in all cases.Comment: 13 pages LATEX, 2 figures using package FEYNMAN, N4-9

High speed motion in water with supercavitation for sub-, trans-, supersonic Mach Numbers

The results of research for supercavitating motion in water at very high speeds comparable with sonic speed ~1500m/s are presented. At such speeds the water is a compressible fluid and the basic compressible hydrodynamics of supercavitating flows together with practical approaches and experimental data are considered. The theory of ballistic projectiles motion is developed with emphasis on the problems of maximal range, lateral motion prediction and problems of minimal declination, hydro-elastic effects, and resonant oscillation frequencies. One main purpose of the article is an attempt to advance the level of understanding of the problem of very high-speed underwater launch by a comprehensive review of previous research on this topic.http://deepblue.lib.umich.edu/bitstream/2027.42/84267/1/CAV2009-final72.pd

A simple approach to estimating three-dimensional supercavitating flow fields

A simple method is formulated for predicting three-dimensional supercavitating flow behind cavitators subject to gravitational acceleration and motion of the cavitator. The method applies slenderbody theory in the context of matched asymptotic expansions to pose an inner problem for the cavity evolution downstream from the locus of cavity detachment. This inner problem is solved by means of a coupled set of equations for the Fourier coefficients characterizing the cavity radius and the velocity potential as a function of downstream location and circumferential location, thus resulting in a two-dimensional multipole solution at each station. For the lowestorder term in the Fourier expansion, it is necessary to match the parabolic inner solution to a fully elliptic outer solution. This step allows the application of any one of a number of methods to solve the axisymmetric problem, which serves as the base solution that is perturbed by the three-dimensional effects. The method is an attempt to formalize the Logvinovich principle of independent cavity section evolution. Results flow past a circular disk cavitator are presented for severalvalues of the cavity Froude number.http://deepblue.lib.umich.edu/bitstream/2027.42/84318/1/CAV2009-final145.pd

Double photoemission from Ag and Pd surfaces: Energy relations

We have investigated the electron pair emission due to single-photon absorption from Ag(100) and Pd(100) surfaces. We are interested in the energy spectra of pairs in particular near the energy cutoff. The sum energy spectra of Ag display a distinctive photon energy dependence. We also observe some fine structure. Near the high-energy cutoff the coincidence rate is too low to determine the energy position of the cutoff. Nevertheless we observe a finite signal if two 5sp electrons near the Fermi level are emitted. For Pd(100) we find sum energy spectra without fine structure and the cutoff region is approached linearly. Within the experimental accuracy the minimum energy to liberate two electrons is twice the work function

High T(c) superconductors: Technical and commercial challenge

Some basic questions of the way which leads from the discovery of high-T(c) superconductors to their applications is surveyed. The influence of high-T(c) superconducting technology on the industrial and social development is also briefly analyzed

Effective Action for High-Energy Scattering in Gravity

The multi-Regge effective action is derived directly from the linearized gravity action. After excluding the redundant field components we separate the fields into momentum modes and integrate over modes which correspond neither to the kinematics of scattering nor to the one of exchanged particles. The effective vertices of scattering and of particle production are obtained as sums of the contributions from the triple and quartic interaction terms and the fields in the effective action are defined in terms of the two physical components of the metric fluctuation.Comment: 15 pages, LATE

Shaping Robust System through Evolution

Biological functions are generated as a result of developmental dynamics that form phenotypes governed by genotypes. The dynamical system for development is shaped through genetic evolution following natural selection based on the fitness of the phenotype. Here we study how this dynamical system is robust to noise during development and to genetic change by mutation. We adopt a simplified transcription regulation network model to govern gene expression, which gives a fitness function. Through simulations of the network that undergoes mutation and selection, we show that a certain level of noise in gene expression is required for the network to acquire both types of robustness. The results reveal how the noise that cells encounter during development shapes any network's robustness, not only to noise but also to mutations. We also establish a relationship between developmental and mutational robustness through phenotypic variances caused by genetic variation and epigenetic noise. A universal relationship between the two variances is derived, akin to the fluctuation-dissipation relationship known in physics

On the forward-backward charge asymmetry in e+e- -annihilation into hadrons at high energies

The forward-backward asymmetry in e+ e- annihilation into a quark-antiquark pair is considered in the double-logarithmic approximation at energies much higher than the masses of the weak bosons. It is shown that after accounting to all orders for the exchange of virtual photons and W, Z -bosons one is lead to the following effect (asymmetry): quarks with positive electric charge (e.g. u, \bar{d}) tend to move in the e+ - direction whereas quarks with negative charges (e.g. d, \bar{u}) tend to move in the e- - direction. The value of the asymmetry grows with increasing energy when the produced quarks are within a cone with opening angle, in the cmf, \theta_0\sim 2M_Z/\sqrt{s} around the e+e- -beam. Outside this cone, at \theta_0 << \theta << 1, the asymmetry is inversely proportional to \theta .Comment: 17 Pages, 2 Tables, 4 Figures. Hadronization effects to the asymmetry are considered with more detail

t-channel Approach to Reggeon Interactions in QCD

Starting from the multi-Regge effective action for high-energy scattering in QCD a $t$-channel approach can be developed which is similar to the approach by White based on general Regge arguments. The BFKL kernel of reggeized gluon interaction, contributions to the $2 \rightarrow 4$ reggeized gluon vertex function and the one-loop correction to the BFKL kernel are considered. The conditions are discussed under which this approach can provide a simple estimante of the next-to-leading logarithmic corrections to the BFKL perturbative pomeron intercept.Comment: latex , 17 figures appended as compressed uuencoded eps file