A two-dimensional finite element model of front surface current flow in cells under non-uniform, concentrated illumination

A two-dimensional finite element model of current flow in the front surface of a PV cell is presented. In order to validate this model we perform an experimental test. Later, particular attention is paid to the effects of non-uniform illumination in the finger direction which is typical in a linear concentrator system. Fill factor, open circuit voltage and efficiency are shown to decrease with increasing degree of non-uniform illumination. It is shown that these detrimental effects can be mitigated significantly by reoptimization of the number of front surface metallization fingers to suit the degree of non-uniformity. The behavior of current flow in the front surface of a cell operating at open circuit voltage under non-uniform illumination is discussed in detail

Bottomonium Production at the Tevatron and the LHC

Inclusive bottomonium hadroproduction at the Tevatron is firstly examined in a Monte Carlo framework with the colour-octet mechanism implemented in the event generation. We extract some NRQCD colour-octet matrix elements relevant for $\Upsilon(1S)$ hadroproduction. Remarkably we find a quite small contribution (compatible with zero) from feeddown of $\chi_{bJ}$ states produced through the colour-octet mechanism: $\Upsilon(1S)$ indirect production via $\chi_{bJ}$ decays should be mainly ascribed to the colour-singlet model. Finally we extrapolate to LHC energies to predict prompt $\Upsilon(1S)$ production rates.Comment: LaTeX, 11 pages, 6 EPS figure

Enhanced thermionic currents by non equilibrium electron population of metals

An analytical expression is derived for the electron thermionic current from heated metals by using a non equilibrium, modified Kappa energy distribution for electrons. This isotropic distribution characterizes the long high energy tails in the electron energy spectrum for low values of the index ? and also accounts for the Fermi energy for the metal electrons. The limit for large ? recovers the classical equilibrium Fermi-Dirac distribution. The predicted electron thermionic current for low ? increases between four and five orders of magnitude with respect to the predictions of the equilibrium Richardson-Dushmann current. The observed departures from this classical expression, also recovered for large ?, would correspond to moderate values of this index. The strong increments predicted by the thermionic emission currents suggest that, under appropriate conditions, materials with non equilibrium electron populations would become more efficient electron emitters at low temperatures

Results from Bottomonia Production at the Tevatron and Prospects for the LHC

We extend our previous analysis on inclusive heavy quarkonia hadroproduction to the whole Upsilon(nS) (n=1,2,3) resonance family. We use a Monte Carlo framework with the colour-octet mechanism implemented in the PYTHIA event generator. We include in our study higher order QCD effects such as initial-state emission of gluons and Altarelli-Parisi evolution of final-state gluons. We extract some NRQCD colour-octet matrix elements relevant for Upsilon(nS) (n=1,2,3) hadroproduction from CDF data at the Fermilab Tevatron. Then we extrapolate to LHC energies to predict prompt bottomonia production rates. Finally, we examine the prospect to probe the gluon density in protons from heavy quarkonia inclusive hadroproduction at high transverse momentum and its feasibility in LHC general-purpose experiments.Comment: LaTeX, 30 pages, 30 EPS figure

Emissive Langmuir Probes in the Strong Emission Regime for the Determination of the Plasma Properties

The determination of the plasma potential Vpl of unmagnetized plasmas by using the floating potential of emissive Langmuir probes operated in the strong emission regime is investigated. The experiments evidence that, for most cases, the electron thermionic emission is orders of magnitude larger than the plasma thermal electron current. The temperature-dependent floating potentials of negatively biased Vpmenor queVpl emissive probes are in agreement with the predictions of a simple phenomenological model that considers, in addition to the plasma electrons, an ad-ditional electron group that contributes to the probe current. The latter would be constituted by a fraction of the repelled electron thermionic current, which might return back to the probe with a different energy spectrum. Its origin would be a plasma potential well formed in the plasma sheath around the probe, acting as a virtual cathode or by collisions and electron thermalization pro-cesses. These results suggest that, for probe bias voltages close to the plasma potential Vp?Vpl, two electron populations coexist, i.e., the electrons from the plasma with temperatureTeand a large group of returned thermionic electrons. These results question the theoretical possibility of measuring the electron temperature by using emissive probes biased to potentials Vp about lower equal than ?Vpl

Power counting and effective field theory for charmonium

We hypothesize that the correct power counting for charmonia is in the parameter Lambda_QCD/m_c, but is not based purely on dimensional analysis (as is HQET). This power counting leads to predictions which differ from those resulting from the usual velocity power counting rules of NRQCD. In particular, we show that while Lambda_QCD/m_c power counting preserves the empirically verified predictions of spin symmetry in decays, it also leads to new predictions which include: A hierarchy between spin singlet and triplet octet matrix elements in the J/psi system. A quenching of the net polarization in production at large transverse momentum. No end point enhancement in radiative decays. We discuss explicit tests which can differentiate between the traditional and new theories of NRQCD.Comment: 18 pages, 1 figure Replaced plot of the psi polarization parameter alpha as a function of transverse momentum. Alpha is now closer to zero for large transverse moment

Bottom Production

We review the prospects for bottom production physics at the LHC.Comment: 74 pages, Latex, 71 figures, to appear in the Report of the ``1999 CERN Workshop on SM physics (and more) at the LHC'', P. Nason, G. Ridolfi, O. Schneider G.F. Tartarelli, P. Vikas (conveners

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Induction avelumab followed by chemoimmunotherapy and maintenance versus chemotherapy alone as first-line therapy in cis-ineligible metastatic urothelial carcinoma (INDUCOMAIN) : a randomized phase II study

Background: Platinum-based chemotherapy (ChT) has been the standard first-line treatment for metastatic urothelial carcinoma (mUC). The purpose of this study was to evaluate the use of induction avelumab followed by avelumab in combination with carboplatin-gemcitabine (carbo/gem) followed by avelumab maintenance. We tested the hypothesis that induction immunotherapy (IO) could enhance the response to ChT and prevent its detrimental effect on immune cells. Materials and methods: INDUCOMAIN is a multicenter, randomized, investigator-initiated, open-label phase II study evaluating the safety and efficacy of induction avelumab before carboplatin-gemcitabine-avelumab, followed by avelumab maintenance (arm A), compared to carbo/gem (arm B). Eligibility criteria included patients with mUC, no prior systemic therapy, and ineligibility for cisplatin by Galsky criteria. Patients were stratified by the presence/absence of visceral metastasis and Eastern Cooperative Oncology Group performance status 0-1 versus 2. The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Results: Eighty-five patients were included and randomized to arm A (n = 42) and arm B (n = 43), respectively. ORR was similar between treatment arms: 59.5% in arm A and 53.5% in arm B (P = 0.57). Fourteen patients (33%) in arm A early progressed/died before or at first response assessment, compared to three patients (7%) in arm B. Median OS was 11.1 months in arm A and 13.2 months in arm B [hazard ratio (HR) 0.91, 95% confidence interval (CI) 0.57-1.46, P = 0.69]. Median PFS was 6.9 months in arm A versus 7.4 months in arm B (HR 0.99, 95% CI 0.61-1.60, P = 0.95). Treatment-related adverse events of grade 3-4 occurred in 70.7% of patients in arm A and in 72.1% in arm B. No predictive role of programmed death-ligand 1 expression was found. Conclusions: The hypothesis that induction avelumab could enhance the efficacy of subsequent ChT was not proven. Administering IO alone as induction before ChT is not an adequate strategy

从小说到戏曲——《廉吏于成龙》剧本创作的艺术匠心

We review theoretical and experimental results relevant to charm and bottom physics. In particular, we consider charmonium and open heavy-flavour production at Tevatron, LEP and HERA colliders, and in heavy-ion scattering. We study the prospect of future b-physics measurement at the LHC with the ATLAS and CMS detectors