3,698 research outputs found

    Determination of f0σf_0-\sigma mixing angle through Bs0J/Ψ f0(980)(σ)B_s^0 \to J/\Psi~f_0(980)(\sigma) decays

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    We study Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) decays, the quark content of f0(980)f_0(980) and the mixing angle of f0(980)f_0(980) and σ(600)\sigma(600). We calculate not only the factorizable contribution in QCD facorization scheme but also the nonfactorizable hard spectator corrections in QCDF and pQCD approach. We get consistent result with the experimental data of Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) and predict the branching ratio of Bs0J/ψσB_s^0 \to J/\psi \sigma. We suggest two ways to determine f0σf_0-\sigma mixing angle θ\theta. Using the experimental measured branching ratio of Bs0J/ψf0(980)B_s^0 \to J/\psi f_0(980) , we can get the f0σf_0-\sigma mixing angle θ\theta with some theoretical uncertainties. We suggest another way to determine f0σf_0-\sigma mixing angle θ\theta using both of experimental measured decay branching ratios Bs0J/ψf0(980)(σ)B_s^0 \to J/\psi f_0(980) (\sigma) to avoid theoretical uncertainties.Comment: arXiv admin note: substantial text overlap with arXiv:0707.263

    Interface control of ferroelectricity in LaNiO3-BaTiO3 superlattices

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    LaNiO3_{3}-BaTiO3_{3} superlattices with different types of interfaces are studied from first-principles density-functional theory. It is revealed that the ferroelectricity in the superlattice with (NiO2_2)^-/(BaO)0^0 interfaces is enhanced from that of the superlattice with (LaO)+^+/(TiO2_2)0^0 interfaces. The origin lies at the polar discontinuity at the interface, which makes the holes localized within the (NiO2_2)^-/(BaO)0^0 interface, but drives a penetration of electrons into BaTiO3_3 component near (LaO)+^+/(TiO2_2)0^0 interface. Our calculations demonstrate an effective avenue to the robust ferroelectricity in BaTiO3_3 ultrathin films.Comment: 14 pages, 6 figure

    Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome

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    <b>AIM:</b> To evaluate differences in flap thickness resulting from use of an Alcon Wavelight FS200 femtosecond laser and a MORIA SBK microkeratome when making a 110-μm-thick corneal flap and to identify the potential factors that affect corneal flap thickness.<b>METHODS:</b> A prospective case study was performed on 120 eyes of 60 patients who were divided into two groups for LASIK, each group consisting of 60 eyes (30 patients). The corneal flaps were created using an Alcon Wavelight FS200 femtosecond laser or a MORIA SBK microkeratome. The central corneal flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness (CCT), spherical equivalent refraction, mean keratometry, and corneal diameter were recorded preoperatively for analysis.<b>RESULTS:</b> Cutting of all flaps was easily performed without intraoperative complications. In the Alcon Wavelight FS200 femtosecond lasergroup, the mean right and left corneal flap thicknesses were 114.0±6.6 μm (range:98-126) and 111.4±7.6 μm (range:98-122), respectively. The difference (2.6±9.1 μm) in the corneal flap thickness between the right and left eyes was not significant (<i>t</i>=1.59, <i>P</i>=0.12). Stepwise regression analysis indicated that the resulting corneal flap thickness was unrelated to the patient’s age, preoperative CCT, spherical equivalent refraction, mean keratometry, or corneal diameter. In the MORIA SBK microkeratome group, the mean right and left corneal flap thicknesses were 110.6±7.4 μm (range:97-125 μm) and 108.2±6.1 μm (range:78-123 μm), respectively. The difference in the corneal flap thickness between the right and left eyes (2.4±6.5μm) was not significant (<i>t</i>=2.039, <i>P</i>=0.0506). The corneal flap thickness was positively correlated with the preoperative CCT through stepwise regression analysis (<i>r</i>=0.297,<i> P</i>=0.021). The corneal flap thickness was not related to age, spherical equivalent refraction, mean keratometry, or corneal diameter. The corneal flap thickness was estimated using the following equation:Tflap=67.77+0.076 CCT (<i>F</i>=5.63, <i>P</i>=0.021).<b>CONCLUSION:</b>Both the Alcon Wavelight FS200 femtosecond laser and the MORIA SBK microkeratome produced 110-μm-thick corneal flaps. The central corneal flap thickness was positively correlated with the preoperative CCT in MORIA SBK microkeratome surgery

    Study on properties of Al film on CFRP after cryogenic-thermal cycling

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    AbstractAl film on CFRP has been tested by cryogenic-thermal cycling according to the especial condition of space. Properties of aluminum film have been characterized by electron pull apparatus, XRD and SEM. The result shows that the adhesion of Al film increases slowly at early stage of cryogenic-thermal cycling. When the times of cryogenic-thermal cycling exceed 50, the adhesion of Al film becomes stability, and then the adhesion of Al film decrease slowly when cycling times from 100 to 600. After 600 times, the adhesion of Al film becomes stability again. The microcrack appears on the surface of Al film after 50 times, and the amounts of microcrack increase and microcrack is coarsening versus times of cryogenic-thermal cycling. The structure of Al film is changing slowly during cryogenic-thermal cycling

    Large-scale Kinetic Simulations of Colliding Plasmas within a Hohlraum of Indirect Drive Inertial Confinement Fusions

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    The National Ignition Facility has recently achieved successful burning plasma and ignition using the inertial confinement fusion (ICF) approach. However, there are still many fundamental physics phenomena that are not well understood, including the kinetic processes in the hohlraum. Shan et al. [Phys. Rev. Lett, 120, 195001, 2018] utilized the energy spectra of neutrons to investigate the kinetic colliding plasma in a hohlraum of indirect drive ICF. However, due to the typical large spatial-temporal scales, this experiment could not be well simulated by using available codes at that time. Utilizing our advanced high-order implicit PIC code, LAPINS, we were able to successfully reproduce the experiment on a large scale of both spatial and temporal dimensions, in which the original computational scale was increased by approximately 7 to 8 orders of magnitude. When gold plasmas expand into deuterium plasmas, a kinetic shock is generated and propagates within deuterium plasmas. Simulations allow us to observe the entire progression of a strong shock wave, including its initial formation and steady propagation. Although both electrons and gold ions are collisional (on a small scale compared to the shock wave), deuterium ions seem to be collisionless. This is because a quasi-monoenergetic spectrum of deuterium ions can be generated by reflecting ions from the shock front, which then leads to the production of neutrons with unusual broadening due to beam-target nuclear reactions. This work displays an unprecedented kinetic analysis of an existing experiment, shedding light on the mechanisms behind shock wave formation. It also serves as a reference for benchmark simulations of upcoming new simulation codes and may be relevant for future research on mixtures and entropy increments at plasma interfaces

    Effect of Reaction and Regeneration on the Production of Pyridine Bases through Glycerol and Ammonia Route

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    The HZSM-22-At-acid and HZSM-5-At-acid catalysts were synthesized by alkaline-acid&nbsp;sequential treatment and the ZnO/HZSM-5-At-acid catalyst was synthesized by wet-impregnated method.&nbsp;Influence factors, including the types of reactors, impurities in glycerol and regeneration, were systematically&nbsp;investigated. The catalysts were characterized by XRD, TG, N2-physorption and NH3-TPD techniques. The&nbsp;catalytic evaluation showed that the total yield of pyridine bases in the series-connected two-stage reactors&nbsp;was significantly higher than that of the single reactor while the catalytic pair (HZSM-22-At-acid +&nbsp;ZnO/HZSM-5-At-acid) was employed in these reactors, respectively. It was found that the presence of&nbsp;methanol and sodium chloride in glycerol played a great negative effect on the total yield of pyridine bases.&nbsp;The coke was a key factor leading to the deactivation of catalyst. The catalytic activity was basically&nbsp;restored after the regeneration. The total yield of pyridine bases was increased up to 72% after the 6 th&nbsp;reaction, which was obviously higher than that of the similar reports. The characterization results&nbsp;demonstrated that the larger pore size and the declined concentration of acid site (particularly strong acid&nbsp;site) were main reasons for improving the catalytic activity

    Electroacupuncture Treatment Normalized Sleep Disturbance in Morphine Withdrawal Rats

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    Sleep disturbance is considered as an important symptom of acute and protracted opiate withdrawal. Current results suggest that sleep disturbance may be taken as a predictor of relapse. Appropriate sleep enhancement therapy will be in favor of the retention in treatment for opiate addicts. Our previous studies have shown that electroacupuncture (EA) is effective in suppressing morphine withdrawal syndrome. The aim of the present study is to investigate the effect of 2 and 100 Hz EA on the sleep disturbance during morphine withdrawal. Rats were made dependent on morphine by repeated morphine injections (escalating doses of 5–80 mg kg−1, subcutaneously, twice a day) for 5 days. EA of 2 or 100 Hz was given twice a day for 3 days, starting at 48 h after the last morphine injection. Electroencephalogram and electromyogram were monitored at the end of the first and the last EA treatments, respectively. Results showed that non-rapid eye movement (NREM) sleep, REM sleep and total sleep time decreased dramatically, while the sleep latency prolonged significantly during acute morphine withdrawal. Both 2 and 100 Hz EA produced a significant increase in NREM sleep, REM sleep and total sleep time. It was suggested that EA could be a potential treatment for sleep disturbance during morphine withdrawal

    A Survey on Location-Driven Influence Maximization

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    Influence Maximization (IM), which aims to select a set of users from a social network to maximize the expected number of influenced users, is an evergreen hot research topic. Its research outcomes significantly impact real-world applications such as business marketing. The booming location-based network platforms of the last decade appeal to the researchers embedding the location information into traditional IM research. In this survey, we provide a comprehensive review of the existing location-driven IM studies from the perspective of the following key aspects: (1) a review of the application scenarios of these works, (2) the diffusion models to evaluate the influence propagation, and (3) a comprehensive study of the approaches to deal with the location-driven IM problems together with a particular focus on the accelerating techniques. In the end, we draw prospects into the research directions in future IM research
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