3,698 research outputs found
Determination of mixing angle through decays
We study decays, the quark content of
and the mixing angle of and . 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 and
predict the branching ratio of . We suggest two ways
to determine mixing angle . Using the experimental
measured branching ratio of , we can get the
mixing angle with some theoretical uncertainties. We
suggest another way to determine mixing angle using both
of experimental measured decay branching ratios to avoid theoretical uncertainties.Comment: arXiv admin note: substantial text overlap with arXiv:0707.263
Interface control of ferroelectricity in LaNiO3-BaTiO3 superlattices
LaNiO-BaTiO superlattices with different types of interfaces are
studied from first-principles density-functional theory. It is revealed that
the ferroelectricity in the superlattice with (NiO)/(BaO)
interfaces is enhanced from that of the superlattice with
(LaO)/(TiO) interfaces. The origin lies at the polar discontinuity
at the interface, which makes the holes localized within the
(NiO)/(BaO) interface, but drives a penetration of electrons into
BaTiO component near (LaO)/(TiO) interface. Our calculations
demonstrate an effective avenue to the robust ferroelectricity in BaTiO
ultrathin films.Comment: 14 pages, 6 figure
Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome
<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
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
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
The HZSM-22-At-acid and HZSM-5-At-acid catalysts were synthesized by alkaline-acid sequential treatment and the ZnO/HZSM-5-At-acid catalyst was synthesized by wet-impregnated method. Influence factors, including the types of reactors, impurities in glycerol and regeneration, were systematically investigated. The catalysts were characterized by XRD, TG, N2-physorption and NH3-TPD techniques. The catalytic evaluation showed that the total yield of pyridine bases in the series-connected two-stage reactors was significantly higher than that of the single reactor while the catalytic pair (HZSM-22-At-acid + ZnO/HZSM-5-At-acid) was employed in these reactors, respectively. It was found that the presence of methanol and sodium chloride in glycerol played a great negative effect on the total yield of pyridine bases. The coke was a key factor leading to the deactivation of catalyst. The catalytic activity was basically restored after the regeneration. The total yield of pyridine bases was increased up to 72% after the 6 th reaction, which was obviously higher than that of the similar reports. The characterization results demonstrated that the larger pore size and the declined concentration of acid site (particularly strong acid site) were main reasons for improving the catalytic activity
Electroacupuncture Treatment Normalized Sleep Disturbance in Morphine Withdrawal Rats
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
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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