3,930 research outputs found

    Identified hadron production at high transverse momenta in p+p collisions at sqrt(NN) = 200 GeV in STAR

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    We report the transverse momentum (pT) distributions for identified charged pions, protons and anti-protons using events triggered by high deposit energy in the Barrel Electro-Magnetic Calorimeter (BEMC) from p + p collisions at psNN = 200 GeV. The spectra are measured around mid-rapidity (|y|<0.5) over the range of 3<pT<15 GeV/c with particle identification (PID) by the relativistic ionization energy loss (rdE/dx) in the Time Projection Chamber (TPC) in the Solenoidal Tracker at RHIC (STAR). The charged pion, proton and anti-proton spectra at high pT are compared with published results from minimum bias triggered events and the Next-Leading-Order perturbative quantum chromodynamic (NLO pQCD) calculations (DSS, KKP and AKK 2008). In addition, we present the particle ratios of pi-/pi+, pbar/p, p/pi+ and pbar/pi- in p + p collisions.Comment: 4 pages, 4 figures, Hot Quark 2008 proceedin

    Development Of A Cathode Designing Method To Avoid Electrodes’ Interference During Blisk Electrochemical Machining

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    Electrochemical machining plays a prominent role in blisk (bladed integrated disk) construction process. Since blisk channel is narrow and twisted, interference between electrodes may happen during electrochemical machining. Therefore, this paper develops a cathode designing method to avoid interference. Firstly, according to theory of electrochemical machining, machined channel is predicted by calculation. Second, with this channel, interference analysis is carried out and a cathode is designed. Finally, the cathode is employed in experiment and no interference appears

    Formation of the seed black holes: a role of quark nuggets?

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    Strange quark nuggets (SQNs) could be the relics of the cosmological QCD phase transition, and they could very likely be the candidate of cold quark matter if survived the cooling of the later Universe, although the formation and evolution of these SQNs depend on the physical state of the hot QGP (quark-gluon plasma) phase and the state of cold quark matter. We reconsider the possibility of SQNs as cold dark matter, and find that the formation of black holes in primordial halos could be significantly different from the standard scenario. In a primordial halo, the collision between gas and SQNs could be frequent enough, and thus the viscosity acting on each SQN would decrease its angular momentum and make it to sink into the center of the halo, as well as heat the gas. The SQNs with baryon numbers less than 103510^{35} could assemble in the center of the halo before the formation of primordial stars. A black hole could form by merger of these SQNs, and then its mass could quickly become about 103 M10^3\ M_\odot or higher, by accreting the surrounding SQNs or gas. The black holes formed in this way could be the seeds for the supermassive black holes at redshift as high as z6z\sim 6.Comment: 15 page

    Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China

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    10.5194/hess-18-1979-2014Hydrology and Earth System Sciences1851979-199

    Reduction of the Three Dimensional Schrodinger Equation for Multilayered Films

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    In this paper, we present a method for reducing the three dimensional Schrodinger equation to study confined metallic states, such as quantum well states, in a multilayer film geometry. While discussing some approximations that are employed when dealing with the three dimensionality of the problem, we derive a one dimensional equation suitable for studying such states using an envelope function approach. Some applications to the Cu/Co multilayer system with regard to spin tunneling/rotations and angle resolved photoemission are discussed.Comment: 14 pages, 1 figur

    Helium-cluster decay widths of molecular states in beryllium and carbon isotopes

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    The α\alpha particle and 6^6He emissions from possible molecular states in beryllium and carbon isotopes have been studied using a mean-field-type cluster potential. Calculations can reproduce well the α\alpha-decay widths of excited states in 8^{8}Be, 12^{12}C and 20^{20}Ne. For the nucleus 10^{10}Be, we discussed the α\alpha-decay widths with different shapes or decay modes, in order to understand the very different decay widths of two excited states. The widths of 6^{6}He decay from 12^{12}Be and α\alpha decays from 13,14^{13,14}C are predicted, which could be useful for future experiments.Comment: 12 pgaes, 1 figur

    Virus-induced gene silencing of TaERECTA increases stomatal density in bread wheat

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    Barley stripe mosaic virus (BSMV)-based virus induced gene silencing (VIGS) is an effective strategy for rapid determination of functional genes in wheat plants. ERECTA genes are reported to regulate stomatal pattern of plants, and manipulation of TaERECTA (a homologue of ERECTA in bread wheat) is a potential route for investigating stomatal development. Here, the leucine-rich repeat domains (LRRs) and transmembrane domains of TaERECTA were selected to gain BSMV:ER-LR and BSMV:ER-TM constructs, respectively, targeting TaERECTA for silencing in wheat cultivars ‘Bobwhite’ and ‘Cadenza’, to identify the function of TaERECTA on stomatal patterns. The results showed that reduced expression of TaERECTA caused an increased stomatal and epidermal cell density by average 13.5% and 3.3%, respectively, due to the significantly reduced size of leaf epidermal and stomatal cells, and this led to an increase in stomatal conductance. These suggest that modulation of TaERECTA offers further opportunities in stomatal engineering for the adaptation of photosynthesis in wheat

    Probing gluon helicity distribution and quark transversity through hyperon polarization in singly polarized pp collisions

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    We study the polarization of hyperon in different processes in singly polarized pppp collisions, in particular its relation to the polarized parton distributions. We show that by measuring hyperon polarization in particularly chosen processes, one can extract useful information on these parton distributions. We show in particular that, by measuring the Σ+\Sigma^+ polarization in high pTp_T direct photon production process, one can extract information on the gluon helicity distribution; and by measuring the transverse polarization of hyeprons with high pTp_T in singly polarized reactions, one can obtain useful information on the transversity distribution. We present the numerical results obtained for those hyperon polarizations using different models for parton distribution function and those for the spin transfer in fragmentation processes.Comment: 25 pages, 8 figures, to appear in Phys. Rev.

    A statistical correlation of sunquakes based on their seismic and white-light emission

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    Several mechanisms have been proposed to explain the transient seismic emission, i.e. “sunquakes,” from some solar flares. Some theories associate high-energy electrons and/or white-light emission with sunquakes. High-energy charged particles and their subsequent heating of the photosphere and/or chromosphere could induce acoustic waves in the solar interior. We carried out a correlative study of solar flares with emission in hard X-rays, enhanced continuum emission at 6173 Å, and transient seismic emission. We selected those flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) with a considerable flux above 50 keV between 1 January 2010 and 26 June 2014. We then used data from the Helioseismic and Magnetic Imager onboard the Solar Dynamic Observatory to search for excess visible-continuum emission and new sunquakes not previously reported. We found a total of 18 sunquakes out of 75 flares investigated. All of the sunquakes were associated with an enhancement of the visible continuum during the flare. Finally, we calculated a coefficient of correlation for a set of dichotomic variables related to these observations. We found a strong correlation between two of the standard helioseismic detection techniques, and between sunquakes and visible-continuum enhancements. We discuss the phenomenological connectivity between these physical quantities and the observational difficulties of detecting seismic signals and excess continuum radiation
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