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141.
The present paper describes the flow characteristics around a rotating grooved circular cylinder with grooves of different
depths. The surface structure of a circular cylinder was varied by changing the depths of 32 arc grooves on the surface. The
surface pressure on the cylinder is measured for theRe range of from 0.4×105 to 1.8×105 and for rotations of from 0 to 4500 rpm. The drag coefficient of a grooved cylinder increases as the spin rate ratio α (=
rotational speed of the cylinder surface/uniform velocity) increases forRe>1.0×105. As the groove depth increases, the drag coefficient of a grooved cylinder is independent from the spin rate ratio α. The
direction of the lift force of a smooth cylinder is opposite to the Magnus force forRe>1.0×105. However, the direction of the lift force of a grooved cylinder is the same as that of the Magnus force for allRe>1.0×105. As the groove depth increases, the increase in the slope of the lift coefficient becomes small. These phenomena are related
to the positions of the flow separation points, which are clarified from the pressure distribution and flow visualization
by the spark tracing method. In addition, in the present study, the flow around a rotating grooved cylinder is clarified by
flow visualization. 相似文献
142.
Chengming Wang Toshiyuki Nagahashi Koichi Aoki Jingyuan Chen 《Journal of Electroanalytical Chemistry》2002,530(1-2)
The conductivity, κ, in a suspension of polystyrene sulfonic latex without supporting electrolyte showed a linear dependence on the volume fraction, vf, of the latex for vf<0.03 with a finite intercept. In contrast, this deviated upward from the linear line for vf>0.03. These variations were qualitatively consistent with the dependence of the voltammetric reduction current of H+ on vf without supporting electrolyte. The current values were only a few percent of the theoretical diffusion-controlled current that could be observed in the suspension with supporting electrolyte. This fact indicates the electrostatic immobilization of the hydrogen ions by sulfonic latex particles. A plot of the current against κ at common values of vf showed that the current for vf>0.07 was smaller than the value predicted from the conductivity. This can be explained in terms of a combination of the increase in electrostatically unbounded H+ estimated by conductance measurements and electric migration in which the electrochemical depletion of [H+] also causes the depletion of the latex. 相似文献
143.
Kazuhisa Uomi Masahiro Aoki Tomonobu Tsuchiya Atsushk Takai 《Fiber and Integrated Optics》1994,13(1):17-29
The high-speed modulation properties of 1.5 μm multiquantum-well λ/4-shifted DFB lasers are filly reviewed. In particular, the dependence of intrinsic dynamic properties, such as relaxation oscillation frequency, nonlinear damping phenomenon, and spectral chirping under 10 Gbit/s direct modulation, on the number of quantum wells is systematically investigated and compared with those of bulk lasers. The results indicate that the dependence of the above three factors on the number of wells is clearly explained by the linear gain saturation of the quantum-well lasers and that the optimum number of wells should be more than ten in order to increase the modulation bandwidth. 相似文献
144.
Anatolij Dvurečenskij Beloslav Riečan 《International Journal of Theoretical Physics》1994,33(7):1387-1402
We present a general decomposition theorem for elements of an ordered group with respect to a cone. This result enables us to obtain decompositions of finitely additive measures defined on quantum logics, orthoalgebras, or, more generally, on difference posets with values in Dedekind complete lattice ordered groups, with respect to a given cone of measures. In particular, we gain Yosida-Hewitt-type and Lebesgue-type decompositions. 相似文献
145.
146.
The nucleon-nucleon (NN) potential is studied by lattice QCD simulations in the quenched approximation, using the plaquette gauge action and the Wilson quark action on a 32(4) [approximately (4.4 fm)(4)] lattice. A NN potential V(NN)(r) is defined from the equal-time Bethe-Salpeter amplitude with a local interpolating operator for the nucleon. By studying the NN interaction in the (1)S(0) and (3)S(1) channels, we show that the central part of V(NN)(r) has a strong repulsive core of a few hundred MeV at short distances (r approximately < 0.5 fm) surrounded by an attractive well at medium and long distances. These features are consistent with the known phenomenological features of the nuclear force. 相似文献
147.
Adare A Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X 《Physical review letters》2007,98(23):232302
We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models. 相似文献
148.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Campbell S Chai JS Chang BS 《Physical review letters》2007,98(23):232301
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2相似文献
149.
Aaltonen T Abulencia A Adelman J Affolder T Akimoto T Albrow MG Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arisawa T Artikov A Ashmanskas W Attal A Aurisano A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Beauchemin PH Bedeschi F Behari S Bellettini G Bellinger J Belloni A Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Bizjak I Blair RE Blocker C Blumenfeld B 《Physical review letters》2007,99(19):191806
We present a search for associated production of the chargino and neutralino supersymmetric particles using up to 1.1 fb{-1} of integrated luminosity collected by the CDF II experiment at the Tevatron pp collider at sq rt[s]=1.96 TeV. We analyze events with a large transverse momentum imbalance and either three charged leptons or two charged leptons of the same electric charge. The numbers of observed events are consistent with standard model expectations. Upper limits on the production cross section are derived in different theoretical models. 相似文献
150.
In order to resolve the long-standing issue of how itinerant ferromagnetism is affected by lattice structure and Hund's coupling, we compare various three-dimensional lattice structures in the single- and multiorbital Hubbard models with the dynamical mean-field theory with an improved quantum Monte Carlo algorithm that preserves the spin-SU(2) symmetry. The result indicates that both the lattice structure and the d-orbital degeneracy are essential for the ferromagnetism in the parameter region representing a transition metal. Specifically, (a) Hund's coupling, despite the common belief, is important, which is here identified to come from particle-hole scatterings, and (b) the ferromagnetism is a correlation effect (outside the Stoner picture) as indicated from the band-filling dependence. 相似文献