Surface impedance of copper MOB depending on the annealing temperature and deformation degree

Results of researches of influence of annealing temperature and deformation degree on mechanical features of copper MOB are presented. It is shown that minimal surface resistance is observed in copper samples that were subject to pre-deformation and were annealed in the range of temperatures 873…923K.Представлены результаты исследований влияния температуры отжига и степени деформации на электромеханические характеристики меди марки МОБ. Показано, что минимальное поверхностное сопротивление наблюдается у меди, деформированной и отожженной в интервале температур 873…923К.Представлені результати досліджень впливу температури відпалу та степені деформації на електромеханічні характеристики міді марки МОБ. Показано, що мінімальний поверхневий опір спостерігається у зразків міді, підверненої деформації і відпаленої в інтервалі температур 873…923К

A unified approach to computation of integrable structures

We expose (without proofs) a unified computational approach to integrable structures (including recursion, Hamiltonian, and symplectic operators) based on geometrical theory of partial differential equations. We adopt a coordinate based approach and aim to provide a tutorial to the computations.Comment: 19 pages, based on a talk on the SPT 2011 conference, http://www.sptspt.it/spt2011/ ; v2, v3: minor correction

Experimental Ka-Band Ground-Based SAR System

An experimental ground-based synthetic aperture radar (GB-SAR) system operating at Ka-band has been developed. The system is designed to be operated from a top a hill or from a building roof, etc. for imaging the underlying ground terrain. The radar hardware system, operating mode and original data processing techniques are described in the paper. A high-duty-cycle long-LFM-pulse mode (quasi-continuous mode) has been used. An effective adaptive matched filtering for range compression has been introduced that provides high dynamic range and high coherency for the radar system. A prominent point processing autofocus has been implemented for the precise estimation and compensation of motion errors of the radar platform. The achieved performance of the GB-SAR system is illustrated with experimental data.Разработана экспериментальная наземная радиолокационная система с синтезированной апертурой (РСА-система), работающая в Ka-диапазоне длин волн. Система спроектирована для работы с вершины холма или крыши здания и т. п. для построения изображений нижерасположенной местности. В статье описана аппаратная часть радиолокатора, режим работы и оригинальные методы обработки данных. Применен режим работы с длинными импульсами с линейной частотной модуляцией с высокой скважностью (квази-непрерывный режим). Предложена техника сжатия импульсов с эффективным адаптивным согласованным фильтром, которая обеспечивает высокий динамический диапазон и высокую когерентность радиолокационной системы. Для точной оценки и компенсации ошибок движения радиолокационной платформы применен метод автофокусировки по сигналам от ярких точек. Достигнутая эффективность наземной РСА-системы проиллюстрирована на экспериментальных данных.Розроблено експериментальну наземну радіолокаційну систему з синтезованою апертурою (РСА-систему), яка працює в Ka-діапазоні довжин хвиль. Систему спроектовано для роботи з вершини пагорба або даху будівлі тощо для побудови зображень нижче розташованої місцевості. В статті описано апаратну частину радіолокатора, режим роботи і оригінальні методи обробки даних. Застосовано режим роботи з довгими імпульсами з лінійною частотною модуляцією з високою скважністю (квазі-неперервний режим). Запропоновано техніку стискання імпульсів з ефективним адаптивним узгодженим фільтром, що забезпечує високий динамічний діапазон та високу когерентність радіолокаційної системи. Для точної оцінки і компенсації помилок руху радіолокаційної платформи використано метод автофокусування за сигналами від яскравих точок. Досягнута ефективність наземної РСА-системи проілюстрована на експериментальних даних

Role of dislocations in formation of ohmic contacts to heavily doped n-Si

We present experimental results concerning a high density of structural defects (in particular, dislocations) in the near-contact region of heavily doped n-silicon. They appear in the course of firing Au Pd Ti Pd -Si n ohmic contact at 450С for 10 min in a vacuum of ~10 Pa⁻⁴ . These defects lead to appearance of metal shunts that determine the current flow mechanism in these ohmic contacts. The calculated and experimental temperature dependences of contact resistivity, ρс(Т), are in good agreement. It is shown that ρс increases with temperature. This is characteristic of a model of ohmic contacts with a high dislocation density in the near-contact region of semiconducto

On a feature of temperature dependence of contact resistivity for ohmic contacts to n-Si with an n⁺ -n doping step

We present both theoretical and experimental temperature dependences of contact resistivity ρс(Т) for ohmic contacts to the silicon n⁺ -n-structures whose n⁺ -layer was formed using phosphorus diffusion or ion implantation. The ρс(Т) dependence was measured in the 125–375 K temperature range with the transmission line method, with allowance made for conduction in both the n⁺ -layer and n⁺ -n doping step

Effective Functional Form of Regge Trajectories

We present theoretical arguments and strong phenomenological evidence that hadronic Regge trajectories are essentially nonlinear and can be well approximated, for phenomenological purposes, by a specific square-root form.Comment: 29 pages, LaTeX. Published versio

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

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

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter