Влияние температур низкопотенциального источника и потребителя теплоты на эффективность теплового насоса

The article describes the experimental setup for testing a heat pump and the results of its operation at various temperatures at its inlet and outlet. An actually task is to study the operation of a heat pump under various boundary conditions, which are determined from the phase transition temperature in the evaporator and condenser. These temperatures depend on the temperature in the evaporator of a low-potential source of heat (the lower source is water, air, etc.) and the temperature in the condenser of a high-potential source of heat (the upper source is a consumer). The main indicator of the efficiency of the heat pump is the coefficient of performance. To determine the reliable value of the coefficient of performance, tests of compression heat pump were carried out. Refrigerant R-142b was used as a working fluid. Based on the experimental data, the dependences of the coefficient of performance on the temperature of the hot and cold heat source are constructed. Also, the coefficient of performance heat pump decreases when the lower heat source decreases.В статье приводятся описание экспериментальной установки для испытания теплового насоса и результаты его работы при различных температурах низкопотенциального источника теплоты и теплопотребителя. От значений этих температур в значительной степени зависит эффективность теплового насоса. Теоретическое определение параметров эффективности дает широкий разброс параметров теплового насоса из-за сложности определения внешних и внутренних потерь, поэтому экспериментальное исследование работы теплового насоса при различных температурных условиях является актуальной задачей. Главным показателем эффективности теплового насоса служит коэффициент преобразования (отношение отданной теплопотребителю теплоты к затраченной в компрессоре работе). Для определения достоверной величины коэффициента преобразования проведены испытания компрессионного теплового насоса. В качестве рабочего тела использовался хладагент R-142b. Установлено, что при увеличении температуры теплопотребителя коэффициент преобразования теплового насоса резко падает. Также коэффициент преобразования теплового насоса понижается при уменьшении температуры низкопотенциального источника теплоты

Development of alternatives for accelerating structure in the range of intermediate proton energy

A scope of the linear accelerating structures for acceleration proton high rower beams in energy range 5… 100 MeV is presented. Main task lies in a possibility to use superconductive equipment. The results are given for +original desgn of accelerating structures of alternating segments being excited on E11-wave on π/2-mode. A possibility is discussed about the use of focusing blocks with the RF–quadrupoles which uniformly fit into the chain of accelerating cells.Приводиться огляд розробок конструкцій структур лінійних прискорювачів протонів з високою потужністю пучка в діапазоні енергій 5...100 МеВ. Основна вимога полягає в можливості використання надпровідної техніки. Описані результати оригінальних розробок прискорюючої структури типу зустрічних сегментів, що збуджується на Е11-хвилі, а також можливість застосування фокусуючих блоків з ВЧ-квадруполями, які однорідно вписуюються в цепочку прискорюючих комірок.Приводится обзор разработок конструкций структур линейных ускорителей протонов с большой мощностью пучка в диапазоне энергий 5...100 МэВ. Главная задача заключается в возможности использования сверхпроводящей техники. Описаны результаты оригинальных разработок ускоряющей структуры типа встречных сегментов, возбуждаемой на Е11-волне, и возможность применения фокусирующих блоков с ВЧ – квадруполями, которые однородно вписываются в цепочку ускоряющих ячеек

Field-linked States of Ultracold Polar Molecules

We explore the character of a novel set of ``field-linked'' states that were predicted in [A. V. Avdeenkov and J. L. Bohn, Phys. Rev. Lett. 90, 043006 (2003)]. These states exist at ultralow temperatures in the presence of an electrostatic field, and their properties are strongly dependent on the field's strength. We clarify the nature of these quasi-bound states by constructing their wave functions and determining their approximate quantum numbers. As the properties of field-linked states are strongly defined by anisotropic dipolar and Stark interactions, we construct adiabatic surfaces as functions of both the intermolecular distance and the angle that the intermolecular axis makes with the electric field. Within an adiabatic approximation we solve the 2-D Schrodinger equation to find bound states, whose energies correlate well with resonance features found in fully-converged multichannel scattering calculations

Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s

In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems

Abstract kinetic equations with positive collision operators

We consider "forward-backward" parabolic equations in the abstract form $Jd \psi / d x + L \psi = 0$, $0< x < \tau \leq \infty$, where $J$ and $L$ are operators in a Hilbert space $H$ such that $J=J^*=J^{-1}$, $L=L^* \geq 0$, and $\ker L = 0$. The following theorem is proved: if the operator $B=JL$ is similar to a self-adjoint operator, then associated half-range boundary problems have unique solutions. We apply this theorem to corresponding nonhomogeneous equations, to the time-independent Fokker-Plank equation $\mu \frac {\partial \psi}{\partial x} (x,\mu) = b(\mu) \frac {\partial^2 \psi}{\partial \mu^2} (x, \mu)$, $0<x<\tau$, $\mu \in \R$, as well as to other parabolic equations of the "forward-backward" type. The abstract kinetic equation $T d \psi/dx = - A \psi (x) + f(x)$, where $T=T^*$ is injective and $A$ satisfies a certain positivity assumption, is considered also.Comment: 20 pages, LaTeX2e, version 2, references have been added, changes in the introductio

Carbon nanowalls: the next step for physical manifestation of the black body coating

The optical properties of carbon nanowall (CNW) films in the visible range have been studied and reported for the first time. Depending on the film structure, ultra-low total reflectance up to 0.13% can be reached, which makes the CNW films a promising candidate for the black body-like coating, and thus for a wide range of applications as a light absorber. We have estimated important trends in the optical property variation from sample to sample, and identified the presence of edge states and domain boundaries in carbon nanowalls as well as the film mass density variation as the key factors. Also we demonstrated that at much lower film thickness and density than for a carbon nanotube forest the CNWs yield one order higher specific light absorption

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio