Structural Transformations in Ni at the Implantation C+ Ions

Structural transformations in nickel films exposed to C+ ions were investigated through the use of electron diffraction and electron microscopy. With an increasing exposure dose, there occurred a smooth transition of the FCC structure of Ni with lattice parameter а=0.352 to the HCP structure of carbide Ni3C with the lattice parameters a=0.266 nm and c=0.433 nm. The completion of the transition was observed once the implanted carbon concentration corresponding to the stoichiometry ratio of Ni3C was attained, this giving evidence for the chemical nature of the structural change observed. However, recognising that atoms of the composite do not form chemical compounds, it is possible to draw a conclusion that atoms of carbon form hexagonal structure and promote reorganisation of atoms of nickel in structure HCP. Thus of introduction atoms carry out a prevailing role in formation of the composite structure

Structural Transformations in Ni at the Implantation C+ Ions

Structural transformations in nickel films exposed to C+ ions were investigated through the use of electron diffraction and electron microscopy. With an increasing exposure dose, there occurred a smooth transition of the FCC structure of Ni with lattice parameter а=0.352 to the HCP structure of carbide Ni3C with the lattice parameters a=0.266 nm and c=0.433 nm. The completion of the transition was observed once the implanted carbon concentration corresponding to the stoichiometry ratio of Ni3C was attained, this giving evidence for the chemical nature of the structural change observed. However, recognising that atoms of the composite do not form chemical compounds, it is possible to draw a conclusion that atoms of carbon form hexagonal structure and promote reorganisation of atoms of nickel in structure HCP. Thus of introduction atoms carry out a prevailing role in formation of the composite structure

Effects of Deuterium Concentration on Deuterium Desorption Temperature Range from Ni - In Composites

Spectra thermal desorption deuterium from the samples of system Ni-In preliminary implanted by var-ious doses of deuterium ions at Т~100 K. On the basis of these spectra are studied dependences of change are constructed. It is shown that the structure of spectrum, thermal desorption deuterium is function doses. On satura-tion of composite Ni70In30 with deuterium through ion implantation at T ~100 K the ultimate attainable concentration of deuterium makes ~2 at.D/at.Met.The increase in deuterium concentration brings about in composite Ni70In30, in addition to the solid state solution deuterium (decomposition at temperature ~530 K), the formation of the hydride, whose temperature of decomposition in vacuum is ~350 K. Change of the component content in system Ni-In leads to essential change of a kind of a spectrum thermal desorption deuterium, shown in occurrence of additional temperature areas desorption (peaks) that testifies to formation of additional structural formations. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3523

Effects of Cold Deformation and Electron Irradiations on Deuterium Desorption Temperature Range from Zr – 1 %Nb Alloy

The explored warm-up ranges of desorption ion-implanted deuterium from Zr – 1 %Nb alloy, with different structure: after crystallization from melt, plastic deformation and irradiations electron. Cool deformation under 300 K Zr – 1 %Nb alloy with degree 3.9 has allowed to reach the nanostructure conditions in alloy with average size crystallite d 61 nm, high three-dimensional concentration of the borders (~ 3,4 %) and significant level microstrain that in spectrum of thermodesorption ion-implanted deuterium was shown as additional low temperature area thermodesorption deuterium within the range of the temperature 770-1000 K. Irradiation electron to energy 10 MeV by fluence ~ 6 × 1017 cm – 2 has brought about active development of the revocable processes in nanostructure alloy: reduction of the average grain size d 58 nm, increase to concentrations of the borders (~ 8,8 %) and appearance additional peaks in spectrum of thermodesorption deuterium with the temperature 700 and 800 K and, accordingly, increase the warmup range desorption deuterium toward reduction of the temperature. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3512

Influence of Deuterium Ion Implantation on the Structure and Hardness of Nanocrystalline Films

Titanium nitride based coatings are very attractive for protection of materials in extreme conditions. However, their behavior under different kinds of irradiation is not entirely well understood. In this work, the influence of ion-implanted deuterium on changes of the structure and mechanical properties TiZrN, TiAlSiN, TiAlYN films were investigated. Films were deposited by filtered vacuum arc plasma technique. After deposition all films were irradiated at room temperature with 12 keV D+ ions to dose 1 1018 D/cm2. Composition, structure and nanohardness of the coatings were determined by X-ray fluorescence method, X-ray diffraction and nanoindentation. The effusion of the implanted deuterium was studied by thermal desorption spectroscopy. It is shown that irradiation by deuterium ions does not make structural changes in multicomponent films. Deuterium thermal desorption spectrum of various coatings are substantially different. Nanohardness of all investigated coatings after irradiation and thermal desorption are decreased. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3545

Effects of Concentration Titanium on Threshold Character of Deuterium Desorption Temperature Range from Mg-based Composites

The plasma evaporation-sputtering method was applied to make composite materials of the Mg-Ti system. The ion-implanted deuterium desorption temperature variations as a function of the component concentration were studied. It has been established that, by introducing titanium into magnesium, the deuterium desorption temperature can be appreciably decreased (to 400-450 K) in comparison with the case of deuterium desorption from magnesium ( 800 K). A step-like shape of the curve of deuterium desorption temperature evidences on the presence of two different structure states of the Mg-Ti system depending on the ratio of components. The deuterium temperature decrease can be caused by filamentary inclusions of insoluble component (titanium) atoms formed in the process of composite making and annealing, providing the deuterium diffusion from the sample at a lower temperature (channels for deuterium diffusion through the surface barrier). The deuterium desorption data obtained on the example of Mg-Ti, Mg-V and Mg-Zr composites provide support for further research into hydrogen storage materials containing low-soluble chemical elements in the alloy component. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3550

Effects of Deuterium Implantation Dose on Hardness and Deuterium Desorption Temperature Range from High Entropy TiVZrNbHf and TiVZrNbHfN Coatings

High entropy TiVZrNbHf and TiVZrNbHfN coatings prepared by filtered vacuum arc plasma from a single equiatomic HEA cathode. Similarly were obtained titanium and titanium nitride coatings. The structure of coatings was investigated by X-ray analysis and the changes in nanohardness by nanoindentation method. The effusion of the implanted deuterium was studied by thermal desorption spectroscopy (TDS). It is shown that the structure of effusion spectrum is a function of deuterium dose. With increasing implantation dose deuterium desorption temperature range from coatings is expanding in the direction of lowering the temperature and the temperature of the peak maximum gas emission gradually shifts to lower temperatures. For nitride coatings deuterium desorption starts at about room temperature and the maximum rate of desorption at a temperature of ~500 K. When irradiation doses more than 5×1017 D/cm2 hardness of nitride coatings decreased by half. Hardness reduction of coatings is caused by occurrence hydride structural formations in coatings. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3536

Effect of deuterium implantation dose on properties of CrN coatings

The methods of X-ray diffraction analysis, atomic-force microscopy, nanoindentation and thermodesorption spectroscopy have been applied to investigate the effect of a dose (from 5∙10¹⁶ to 1.5∙10¹⁸ D/сm²) of implanted deuterium with energy of 24 keV on the structure, surface morphology and mechanical properties of vacuum-arc CrN coatings. Deuterium ion implantation in the range of doses from 5∙10¹⁶ to 1.5∙10¹⁷ D/сm² decreases by 10…15% the nanohardness and elastic modulus of coatings. Under exposition to doses ≥ 1∙10¹⁸ D/сm² the coating nanohardness sharply decreases because of blisters being formed and occupying about 30% of the CrN coating surface. Deuterium implantation did not lead to formation of new phases in the CrN coating.Методами рентгеноструктурного аналізу, атомно-силової мікроскопії, наноіндентування і термодесорбційної спектроскопії досліджено вплив дози (5∙10¹⁶…1.5∙10¹⁸ D/см²) імплантованого дейтерію з енергією 24 кеВ на структуру, морфологію поверхні та механічні властивості вакуумно-дугових покриттів CrN. Імплантований дейтерій в інтервалі доз 5∙10¹⁶…1.5∙10¹⁷ D/см² призводить до зменшення на 10…15% нанотвердості і модуля пружності покриттів. Опромінення дозами ≥ 1∙10¹⁸ D/см² викликає різке зниження нанотвердості покриттів через формування блістерів, які займають близько 30% поверхні покриття CrN. Імплантація дейтерію не призводить до утворення нових фаз у покритті CrN.Методами рентгеноструктурного анализа, атомно-силовой микроскопии, наноиндентирования и термодесорбционной спектроскопии исследовано влияния дозы (5∙10¹⁶…1,5∙10¹⁸ D/см²) имплантированного дейтерия с энергией 24 кэВ на структуру, морфологию поверхности и механические свойства вакуумно-дуговых покрытий CrN. Имплантированный дейтерий в интервале доз 5∙10¹⁶…5∙10¹⁷ D/см² приводит к уменьшению на 10…15% нанотвердости и модуля упругости покрытий. Облучение дозами ≥ 1∙10¹⁸ D/см² вызывает резкое снижение нанотвердости покрытий из-за формирования блистеров, которые занимают около 30% поверхности покрытия CrN. Имплантация дейтерия не приводит к образованию новых фаз в покрытии CrN

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