نتایج جستجو برای: deep beams
تعداد نتایج: 242332 فیلتر نتایج به سال:
We report the confinement and cooling of an optically dense cloud of neutral sodium atoms by radiation pressure. The trapping and damping forces were provided by three retroreflected laser beams propagating along orthogonal axes, with a weak magnetic field used to distinguish between the beams. We have trapped as many as 10 7 atoms for 2 min at densities exceeding lOll atoms cm -3. The trap was...
The HERA collider circulates beams of electrons (positrons) and protons at energies of 27.5 and 820GeV respectively. The ep centre of mass energy for collisions between the beams is 300GeV. The largest cross-section processes observed in these collisions are photoproduction reactions, where the e beam acts as a source of almost real (Q ≪ 1GeV) photons. Processes where a virtual photon of sizeab...
The signal and idler beams from a picosecond, synchronously pumped optical parametric oscillator (OPO) provide the two colors necessary for coherent anti-Stokes Raman scattering (CARS) microscopy. The OPO provides a continuously tunable frequency difference between the two beams over a broad range of Raman shifts (100-3700 cm(-1)) by varying the temperature of a single nonlinear crystal. The ne...
We study the sensitivities of space infrared interferometers. We formulate the signal-to-noise ratios of infrared images obtained by aperture synthesis in the presence of source shot noise, background shot noise, and detector read noise. We consider the case in which n beams are combined pairwise at n(n-1)/2 detectors and the case in which all the n beams are combined at a single detector. We a...
We present a calculation of the NLO QCD corrections to heavy flavor photoproduction with longitudinally polarized beams. We apply our results to study the spin asymmetry for total charm quark production which will be used for a first direct determination of ∆g by the COMPASS experiment. We also briefly discuss the main theoretical uncertainties inherent in this calculation. Talk presented at th...
in this research, using the modified compression field theory (mcft), a new truss based model is proposed to predict the behavior of reinforced concrete coupling beams with diagonal reinforcement. the model is able to consider the effects of shear and axial forces and bending moment, simultaneously. the proposed model includes a nonlinear shear spring, an axial spring, two inclined truss member...
the present research is concerned with the determination of ductility, over-strength and response modification factors of coupled steel shear wall frames. three structural models with various numbers of stories, bay width and coupling beam height were analyzed using static pushover and incremental nonlinear dynamic analyses. the ductility, over-strength and response modification factors for the...
Heavy ion beams have many exciting applications, including radiotherapy of deep-seated tumors and simulation tests of space irradiation for astronauts. These beams often use a feature that concentrates the energy deposition largely along the end of the energy pathway, leading to different distributions of biological effects along the axial direction. Currently, there is relatively little inform...
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