1,200 research outputs found

    On dynamical net-charge fluctuations within a hadron resonance gas approach

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    The dynamical net-charge fluctuations (Îœdyn{\nu}_{dyn}) in different particle ratios K/πK/{\pi}, K/pK/p, and p/πp/{\pi} are calculated from the hadron resonance gas (HRG) model and compared with STAR central Au+Au collisions at sNN=7.7−200 \sqrt{s_{NN}}=7.7-200~GeV and NA49 central Pb+Pb collisions at sNN=6.3−17.3 \sqrt{s_{NN}}=6.3-17.3~GeV. The three charged-particle ratios (K/πK/{\pi}, K/pK/p, and p/πp/{\pi}) are determined as total and average of opposite and average of same charges. We find an excellent agreement between the HRG calculations and the experimental measurements, especially from STAR beam energy scan (BES) program, while the strange particles in the NA49 experiment at lower Super Proton Synchrotron (SPS) energies are not reproduced by the HRG approach. We conclude that the utilized HRG version seems to take into consideration various types of correlations including strong interactions through the heavy resonances and their decays especially at BES energies.Comment: 8 pages, 1 figure, accepted for publication in Advances in High Energy Physic

    Saturable discrete vector solitons in one-dimensional photonic lattices

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    Localized vectorial modes, with equal frequencies and mutually orthogonal polarizations, are investigated both analytically and experimentally in a one-dimensional photonic lattice with saturable nonlinearity. It is shown that these modes may span over many lattice elements and that energy transfer among the two components is both phase and intensity dependent. The transverse electrically polarized mode exhibits a single-hump structure and spreads in cascades in saturation, while the transverse magnetically polarized mode exhibits splitting into a two-hump structure. Experimentally such discrete vector solitons are observed in lithium niobate lattices for both coherent and mutually incoherent excitations.Comment: 4 pages, 5 figures (reduced for arXiv

    Robust Design of RF-MEMS Cantilever Switches Using Contact Physics Modeling

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    This paper presents the robust design optimization of an RF-MEMS direct contact cantilever switch for minimum actuation voltage and opening time, and maximum power handling capability. The design variables are the length and thickness of the entire cantilever, the widths of the sections of the cantilever, and the dimple size. The actuation voltage is obtained using a 3-D structural-electrostatic finite-element method (FEM) model, and the opening time is obtained using the same FEM model and the experimental model of adhesion at the contact surfaces developed in our previous work. The model accounts for an unpredictable variance in the contact resistance resulting from the micromachining process for the estimation of the power handling. This is achieved by taking the ratio of the root mean square power of the RF current (signal") passing through the switch to the contact temperature ("noise") resulting from the possible range of the contact resistance. The resulting robust optimization problem is solved using a Strength Pareto Evolutionary Algorithm, to obtain design alternatives exhibiting different tradeoffs among the three objectives. The results show that there exists substantial room for improved designs of RF-MEMS direct-contact switches. It also provides a better understanding of the key factors contributing to the performances of RF-MEMS switches. Most importantly, it provides guidance for further improvements of RF-MEMS switches that exploit complex multiphysics phenomena.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87274/4/Saitou7.pd

    Effect of Phacoemulsification on Intraocular Pressure in Eyes with Functioning Tube Shunts

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    Purpose: To evaluate the effect of phacoemulsification on intraocular pressure (IOP) in eyes with functioning tube shunts. Methods: This was a retrospective chart review of primary open-angle glaucoma (POAG) patients with a functioning tube who underwent phacoemulsification and had ≄24 months of follow-up. The primary end point was defined as surgical failure (IOP > 21 mmHg) at month 24, progression to no light perception (NLP) vision, glaucoma reoperation, or implant removal. Surgical failure defined as IOP >18 and >15 mmHg, changes in visual acuity (VA), IOP, and number of medications were assessed. Results: Twenty-seven eyes of 27 patients with moderate or severe POAG were included. The mean age of the patients was 64.2 ± 10.8 years. The interval between the tube shunt and phacoemulsification was 28.8 ± 25.0 months. At the end of the study, four (14.8%) eyes met the failure criteria; the average time to failure was 9.3 ± 3.8 months. The causes of failure were high IOP in two (50.0%) and glaucoma reoperation in two (50.0%) eyes; however, no eyes progressed to NLP vision. Surgical failure defined as IOP >18 and >15 mmHg showed an increasing failure rate (18.5% and 48.5%, respectively). The mean IOP and medications number remained stable at month 24 compared to baseline (P = 0.131 and P = 0.302, respectively). Initially, VA showed improvement, with the greatest improvement at 6 months (P = 0.001), but at 24 months the improvement was no longer significant (P = 0.430). Conclusion: Phacoemulsification in patients with functioning tubes did not change the mean IOP in most of the patients (86.2%); the number of medications also did not increase

    Magnetoplasmonic design rules for active magneto-optics

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    Light polarization rotators and non-reciprocal optical isolators are essential building blocks in photonics technology. These macroscopic passive devices are commonly based on magneto-optical Faraday and Kerr polarization rotation. Magnetoplasmonics - the combination of magnetism and plasmonics - is a promising route to bring these devices to the nanoscale. We introduce design rules for highly tunable active magnetoplasmonic elements in which we can tailor the amplitude and sign of the Kerr response over a broad spectral range
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