546 research outputs found
Problems of the implementation of energy-saving technologies in heat supply
The article discusses a number of problems associated with the introduction of energy saving technologies in heat supply organizations. It characterizes the current state of the legal framework in the field of the energy saving in heat supply; observed trends in the implementation of energy efficiency programs in the district heating companies; a program of energy conservation and energy efficiency of Russia until 2020 was analyzed. On the basis of a comprehensive analysis of a number of heat suppliers, authors reveal the typical problems of the introduction of energy saving technologies
Problems of the implementation of energy-saving technologies in heat supply
The article discusses a number of problems associated with the introduction of energy saving technologies in heat supply organizations. It characterizes the current state of the legal framework in the field of the energy saving in heat supply; observed trends in the implementation of energy efficiency programs in the district heating companies; a program of energy conservation and energy efficiency of Russia until 2020 was analyzed. On the basis of a comprehensive analysis of a number of heat suppliers, authors reveal the typical problems of the introduction of energy saving technologies
Quantum reflection of antihydrogen from a liquid helium film
We study the quantum reflection of ultracold antihydrogen atoms bouncing on
the surface of a liquid helium film. The Casimir-Polder potential and quantum
reflection are calculated for different thicknesses of the film supported by
different substrates. Antihydrogen can be protected from anni- hilation for as
long as 1.3s on a bulk of liquid 4He, and 1.7s for liquid 3He. These large
lifetimes open interesting perspectives for spectroscopic measurements of the
free fall acceleration of antihydrogen. Variation of the scattering length with
the thickness of a film of helium shows interferences which we interpret
through a Liouville transformation of the quantum reflection problem
Antiproton-Hydrogen annihilation at sub-kelvin temperatures
The main properties of the interaction of ultra low-energy antiprotons ( a.u.) with atomic hydrogen are established. They include the
elastic and inelastic cross sections and Protonium (Pn) formation spectrum. The
inverse Auger process () is taken into account in the
framework of an unitary coupled-channels model. The annihilation cross-section
is found to be several times smaller than the predictions made by the black
sphere absorption models. A family of nearthreshold metastable
states is predicited. The dependence of Protonium formation probability on the
position of such nearthreshold S-matrix singularities is analysed. An
estimation for the annihilation cross section is obtained.Comment: latex.tar.gz file, 22 pages, 9 figure
Extreme Raman red shift: Ultrafast multimode nonlinear space-time dynamics, pulse compression, and broadly tunable frequency conversion
Ultrashort high-energy pulses at wavelengths longer than 1 μm are now desirable for a vast variety of applications in ultrafast and strong-field physics. To date, the main answer to the wavelength tunability for energetic, broadband pulses still relies on optical parametric amplification (OPA), which often requires multiple and complex stages, may feature imperfect beam quality, and has limited conversion efficiency into one of the amplified waves. In this work, we present a completely different strategy to realize an energy-efficient and scalable laser frequency shifter. This relies on the continuous red shift provided by stimulated Raman scattering (SRS) over a long propagation distance in nitrogen-filled hollow-core fibers (HCF). We show a continuous tunability of the laser wavelength from 1030 nm up to 1730 nm with a conversion efficiency higher than 70% and high beam quality. The highly asymmetric spectral broadening, arising from the spatiotemporal nonlinear interplay between higher-order modes of the HCF, can be readily employed to generate pulses (∼20 fs) significantly shorter than the pump ones (∼200 fs) with high beam quality, and the pulse energy can further be scaled up to tens of millijoules. We envision that this technique, coupled with the emerging high-power Yb laser technology, has the potential to answer the increasing demand for energetic multi-TW few-cycle sources tunable in the near-IR
SUSY approach to Pauli Hamiltonians with an axial symmetry
A two-dimensional Pauli Hamiltonian describing the interaction of a neutral
spin-1/2 particle with a magnetic field having axial and second order
symmetries, is considered. After separation of variables, the one-dimensional
matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum
mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and
also to the Hamiltonian hierarchies generated by intertwining operators. The
spectrum is studied by means of the associated matrix shape-invariance. The
relation between the intertwining operators and the second order symmetries is
established and the full set of ladder operators that complete the dynamical
algebra is constructed.Comment: 18 pages, 3 figure
Increased distractibility in schizotypy: Independent of individual differences in working memory capacity?
Individuals with schizophrenia typically show increased levels of distractibility. This has been attributed to impaired working memory capacity (WMC), since lower WMC is typically associated with higher distractibility, and schizophrenia is typically associated with impoverished WMC. Here, participants performed verbal and spatial serial recall tasks that were accompanied by to-be-ignored speech tokens. For the few trials wherein one speech token was replaced with a different token, impairment was produced to task scores (a deviation effect). Participants subsequently completed a schizotypy questionnaire and a WMC measure. Higher schizotypy scores were associated with lower WMC (as measured with operation span, OSPAN), but WMC and schizotypy scores explained unique variance in relation to the mean magnitude of the deviation effect. These results suggest that schizotypy is associated with heightened domain-general distractibility, but that this is independent of its relationship with WMC
Resonant Phenomena in Antihydrogen-Hydrogen Scattering
We present a treatment of cold hydrogen-antihydrogen collisions based on the
asymptotic properties of atom-antiatom interactions. We derive general formulas
for the elastic and inelastic cross sections and for the scattering lengths and
analyze their sensitivity to the parameters characterizing the inelasticity of
the collision process. Given the inelasticity, we obtain bounds for the complex
scattering length. We investigate the influence of strong nuclear forces and
the isotope effects in and collisions
and demonstrate enhancement of these effects due to the presence of the
near-threshold narrow () states. The
values of the elastic and inelastic cross-sections with simultaneous account of
rearrangement and strong forces are presented. General expressions for the
(complex) energies of the near-threshold states are
obtained.Comment: 26 pages 7 figure
Guiding Neutral Atoms with a Wire
We demonstrate guiding of cold neutral atoms along a current carrying wire.
Atoms either move in Kepler-like orbits around the wire or are guided in a
potential tube on the side of the wire which is created by applying an
additional homogeneous bias field. These atom guides are very versatile and
promising for applications in atom optics.Comment: 4 pages, 6 figures, submitted to PR
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