Searching for high-KK isomers in the proton-rich A∼80A\sim80 mass region

Configuration-constrained potential-energy-surface calculations have been performed to investigate the $K$ isomerism in the proton-rich $A\sim80$ mass region. An abundance of high-$K$ states are predicted. These high-$K$ states arise from two and four-quasi-particle excitations, with $K^{\pi}=8^{+}$ and $K^{\pi}=16^{+}$, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under studies are prolate spheroids in their ground states, the oblate shapes of the predicted high-$K$ states may indicate a combination of $K$ isomerism and shape isomerism

First-principles and model simulation of all-optical spin reversal

All-optical spin switching is a potential trailblazer for information storage and communication at an unprecedented fast rate and free of magnetic fields. However, the current wisdom is largely based on semiempirical models of effective magnetic fields and heat pulses, so it is difficult to provide high-speed design protocols for actual devices. Here, we carry out a massively parallel first-principles and model calculation for thirteen spin systems and magnetic layers, free of any effective field, to establish a simpler and alternative paradigm of laser-induced ultrafast spin reversal and to point out a path to a full-integrated photospintronic device. It is the interplay of the optical selection rule and sublattice spin orderings that underlines seemingly irreconcilable helicity-dependent/independent switchings. Using realistic experimental parameters, we predict that strong ferrimagnets, in particular, Laves phase C15 rare-earth alloys, meet the telecommunication energy requirement of 10 fJ, thus allowing a cost-effective subpicosecond laser to switch spin in the GHz region.Comment: 23 pages, 6 figures and one tabl

Numerical Simulation of Quartz Tube Solid Particle Air Receiver

AbstractThe quartz tube solid particle air receiver is a new type of solar receiver in which fluidized particles absorb the solar radiation directly and heat the air effectively, improving the efficiency of solar thermal power generation and reducing costs. In this article, transient numerical simulation was conducted to simulate the heat transfer and flow processes in single quartz tube under concentrated solar radiation. The results showed that the distribution of solid particles temperature was uniform in the fluidized region, which could overcome the problem of overheating in the volumetric solar receiver. The temperature difference between solid particles and air was no more than 25K, indicating that heat transfer between particles and air was very effective. Further, as the direct solar radiation increased, the average air temperature in the outlet increased while the thermal efficiency decreased. The high tube wall temperature caused heat loss to the environment by radiative and convective heat transfer. With the air inlet velocity increasing, the averaging air temperature in the outlet decreased while the efficiency of the receiver increased. The simulation results provided important reference for improving the performance of the quartz tube solid particle air receiver

Ratio of Hadronic Decay Rates of J\psi and \psi(2S) and the \rho\pi Puzzle

The so-called \rho\pi puzzle of J\psi and \psi(2S) decays is examined using the experimental data available to date. Two different approaches were taken to estimate the ratio of J\psi and \psi(2S) hadronic decay rates. While one of the estimates could not yield the exact ratio of \psi(2S) to J\psi inclusive hadronic decay rates, the other, based on a computation of the inclusive ggg decay rate for \psi(2S) (J\psi) by subtracting other decay rates from the total decay rate, differs by two standard deviations from the naive prediction of perturbative QCD, even though its central value is nearly twice as large as what was naively expected. A comparison between this ratio, upon making corrections for specific exclusive two-body decay modes, and the corresponding experimental data confirms the puzzles in J\psi and \psi(2S) decays. We find from our analysis that the exclusively reconstructed hadronic decays of the \psi(2S) account for only a small fraction of its total decays, and a ratio exceeding the above estimate should be expected to occur for a considerable number of the remaining decay channels. We also show that the recent new results from the BES experiment provide crucial tests of various theoretical models proposed to explain the puzzle.Comment: 8 pages, no figure, 4 table

Two monotonic functions involving gamma function and volume of unit ball

In present paper, we prove the monotonicity of two functions involving the gamma function $\Gamma(x)$ and relating to the $n$-dimensional volume of the unit ball $\mathbb{B}^n$ in $\mathbb{R}^n$.Comment: 7 page

The detector system of the Daya Bay reactor neutrino experiment

The Daya Bay experiment was the first to report simultaneous measurements of reactor antineutrinos at multiple baselines leading to the discovery of (nu) over bar (e) oscillations over km-baselines. Subsequent data has provided the world\u27s most precise measurement of sin 2 2013 and the effective mass splitting Delta m(ee)(2). The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world\u27s most prolific sources of electron antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors\u27 baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking. (C) 2015 Elsevier B.V. All rights reserved

The Gaussian approximation for multi-color generalized Friedman's urn model

The Friedman's urn model is a popular urn model which is widely used in many disciplines. In particular, it is extensively used in treatment allocation schemes in clinical trials. In this paper, we prove that both the urn composition process and the allocation proportion process can be approximated by a multi-dimensional Gaussian process almost surely for a multi-color generalized Friedman's urn model with non-homogeneous generating matrices. The Gaussian process is a solution of a stochastic differential equation. This Gaussian approximation together with the properties of the Gaussian process is important for the understanding of the behavior of the urn process and is also useful for statistical inferences. As an application, we obtain the asymptotic properties including the asymptotic normality and the law of the iterated logarithm for a multi-color generalized Friedman's urn model as well as the randomized-play-the-winner rule as a special case