3,014 research outputs found

    Modified dispersion relations and black hole physics

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    A modified formulation of energy-momentum relation is proposed in the context of doubly special relativity. We investigate its impact on black hole physics. It turns out that such modification will give corrections to both the temperature and the entropy of black holes. In particular this modified dispersion relation also changes the picture of Hawking radiation greatly when the size of black holes approaching the Planck scale. It can prevent black holes from total evaporation, as a result providing a plausible mechanism to treat the remnant of black holes as a candidate for dark matter.Comment: 4 pages, Revtex. Final version to appear in PR

    Mutual correlation in the shock wave geometry

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    We probe the shock wave geometry with the mutual correlation in a spherically symmetric Reissner Nordstr\"om AdS black hole on the basis of the gauge/gravity duality. In the static background, we find that the regions living on the boundary of the AdS black holes are correlated provided the considered regions on the boundary are large enough. We also investigate the effect of the charge on the mutual correlation and find that the bigger the value of the charge is, the smaller the value of the mutual correlation will to be. As a small perturbation is added at the AdS boundary, the horizon shifts and a dynamical shock wave geometry forms after long time enough. In this dynamic background, we find that the greater the shift of the horizon is, the smaller the mutual correlation will to be. Especially for the case that the shift is large enough, the mutual correlation vanishes, which implies that the considered regions on the boundary are uncorrelated. The effect of the charge on the mutual correlation in this dynamic background is found to be the same as that in the static background.Comment: 10 page

    An integrated approach for remanufacturing job shop scheduling with routing alternatives.

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    Remanufacturing is a practice of growing importance due to increasing environmental awareness and regulations. However, the stochastic natures inherent in the remanufacturing processes complicate its scheduling. This paper undertakes the challenge and presents a remanufacturing job shop scheduling approach by integrating alternative routing assignment and machine resource dispatching. A colored timed Petri net is introduced to model the dynamics of remanufacturing process, such as various process routings, uncertain operation times for cores, and machine resource conflicts. With the color attributes in Petri nets, two types of decision points, recovery routing selection and resource dispatching, are introduced and linked with places in CTPN model. With time attributes in Petri nets, the temporal aspect of recovery operations for cores as well as the evolution dynamics in cores\u27 operational stages is mathematically analyzed. A hybrid meta-heuristic algorithm embedded scheduling strategy over CTPN is proposed to search for the optimal recovery routings for worn cores and their recovery operation sequences on workstations, in minimizing the total production cost. The approach is demonstrated through the remanufacturing of used machine tool and its effectiveness is compared against another two cases: baseline case with fixed recovery process routings and case 2 using standard SA/MST

    Design of High-Speed and Low-Power Comparator in Flash ADC

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    AbstractIn this paper, a high-speed low-power comparator, which is used in a 2 Gsps, 8 bit Flash ADC, is designed and simulated. Based on 0.18 um TSMC CMOS process model, the comparator circuit is simulated with a 1.8V power supply in Cadence environment. The result shows that it can work at a 2GHZ clock frequency, and the dynamic power consumption is only 1.2mW, with 123.5ps transmission delay. In addition, the average offset voltage of this comparator is only 676.3uV, which can meet the requirements of an 8-bit Flash ADC

    Less suppressed μ→eγ and τ→μγ loop amplitudes and extra dimension theories

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    AbstractWhen μeγ (or τμγ) loop involves a vector boson, the amplitude is suppressed by more than two powers of heavy particle masses. However we show that the scalar boson loop diagrams are much less damped. Particularly, the loop amplitude in which the intermediate fermion and scalar boson have comparable masses is as large as possible, as allowed by the decoupling theorem. Such a situation is realized in the “universal extra dimension theory”, and can yield a large enough rate for μeγ to be detectable in current experiments. Our investigation involves precise calculation of the scalar boson loop's dependence on the masses of the intermediate states

    Blow up solutions to a viscoelastic fluid system and a coupled Navier-Stokes/Phase-Field system in R^2

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    We find explicit solutions to both the Oldroyd-B model with infinite Weissenberg number and the coupled Navier-Stokes/Phase-Field system. The solutions blow up in finite time.Comment: 5 page

    Minimally invasive surgery for uterine fibroids

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    The incidence of uterine fibroids, which comprise one of the most common female pelvic tumors, is almost 70–75% forwomen of reproductive age. With the development of surgical techniques and skills, more individuals prefer minimallyinvasive methods to treat uterine fibroids. There is no doubt that minimally invasive surgery has broad use for uterinefibroids. Since laparoscopic myomectomy was first performed in 1979, more methods have been used for uterine fibroids,such as laparoscopic hysterectomy, laparoscopic radiofrequency volumetric thermal ablation, and uterine artery embolization,and each has many variations. In this review, we compared these methods of minimally invasive surgery for uterinefibroids, analyzed their benefits and drawbacks, and discussed their future development

    Chinese industrial air pollution emissions based on the continuous emission monitoring systems network

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    As the world's largest industrial producer, China has generated large amount of industrial atmospheric pollution, particularly for particulate matter (PM), SO2 and NOx emissions. A nationwide, time-varying, and up-to-date air pollutant emission inventory by industrial sources has great significance to understanding industrial emission characteristics. Here, we present a nationwide database of industrial emissions named Chinese Industrial Emissions Database (CIED), using the real smokestack concentrations from China's continuous emission monitoring systems (CEMS) network during 2015-2018 to enhance the estimation accuracy. This hourly, source-level CEMS data enables us to directly estimate industrial emission factors and absolute emissions, avoiding the use of many assumptions and indirect parameters that are common in existing research. The uncertainty analysis of CIED database shows that the uncertainty ranges are quite small, within ±7.2% for emission factors and ±4.0% for emissions, indicating the reliability of our estimates. This dataset provides specific information on smokestack concentrations, emissions factors, activity data and absolute emissions for China's industrial emission sources, which can offer insights into associated scientific studies and future policymaking

    N,N′-Bis(2,6-diisopropyl­phen­yl)-3,6-di­methyl-1,2,4,5-tetra­zine-1,4-dicarboxamide

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    In the title mol­ecule, C30H42N6O2, the amide-substituted N atoms of the tetra­zine ring deviate from the approximate plane of the four other atoms in the ring by 0.457 (3) and 0.463 (3) Å, forming a boat conformation. The two benzene rings form a dihedral angle of 47.69 (9)°. Intra­molecular N—H⋯N and weak C—H⋯O hydrogen bonds are observed
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