Unified unquenched quark model for heavy-light mesons with chiral dynamics

In this work, an unquenched quark model is proposed for describing the heavy-light mesons by taking into account the coupled-channel effects induced by chiral dynamics. After including a relativistic correction term for the strong transition amplitudes, both the mass spectra and decay widths of the observed heavy-light mesons can be successfully described simultaneously in a unified framework, several long-standing puzzles related to the small masses and broad widths are overcome naturally. We also provide valuable guidance in searching new heavy-light mesons by the detailed predictions of their masses, widths, and branching ratios. The success of the unquenched quark model presented in this work indicates it may be an important step for understanding the hadron spectrum.Comment: 12 pages, 3 figure

Further understanding the nature of Ω(2012)\Omega(2012) within a chiral quark model

In our previous works, we have analyzed the two-body strong decays of the low-lying $\Omega$ baryon states within a chiral quark model. The results show that the $\Omega(2012)$ resonance favors the three-quark state with $J^P=3/2^-$ classified in the quark model. With this assignment, in the present work we further study the three-body strong decay $\Omega(2012)\to \Xi^*(1530)\bar{K} \to \Xi\pi\bar{K}$ and coupled-channel effects on $\Omega(2012)$ from nearby channels $\Xi \bar{K}$, $\Omega\eta$ and $\Xi^*(1530)\bar{K}$ within the chiral quark model as well. It is found that the $\Omega(2012)$ resonance has a sizeable decay rate into the three-body final state $\Xi\pi\bar{K}$. The predicted ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}=\mathcal{B}[\Omega(2012)\to \Xi^*(1530)\bar{K}\to \Xi\pi\bar{K}]/\mathcal{B}[\Omega(2012)\to \Xi\bar{K}]\simeq 12\%$ is close to the up limit $11\%$ measured by the Belle Collaboration in 2019, however, our predicted ratio is too small to be comparable with the recent data $0.97\pm 0.31$. Furthermore, our results show that the coupled-channel effects on the $\Omega(2012)$ is not large, its components should be dominated by the bare three-quark state, while the proportion of the molecular components is only $\sim 16\%$. To clarify the nature of $\Omega(2012)$, the ratio $R_{\Xi\bar{K}}^{\Xi\pi\bar{K}}$ is expected to be tested by other experiments.Comment: 7 pages, 3 figure

A Magnetic Reconnection model for Hot Explosions in the Cool Atmosphere of the Sun

UV bursts and Ellerman bombs are transient brightenings observed in the low solar atmospheres of emerging flux regions. Observations have discovered the cospatial and cotemporal EBs and UV bursts, and their formation mechanisms are still not clear. The multi-thermal components with a large temperature span in these events challenge our understanding of magnetic reconnection and heating mechanisms in the low solar atmosphere. We have studied magnetic reconnection between the emerging and background magnetic fields. The initial plasma parameters are based on the C7 atmosphere model. After the current sheet with dense photosphere plasma is emerged to $0.5$ Mm above the solar surface, plasmoid instability appears. The plasmoids collide and coalesce with each other, which makes the plasmas with different densities and temperatures mixed up in the turbulent reconnection region. Therefore, the hot plasmas corresponding to the UV emissions and colder plasmas corresponding to the emissions from other wavelenghts can move together and occur at about the same height. In the meantime, the hot turbulent structures basically concentrate above $0.4$ Mm, whereas the cool plasmas extend to much lower heights to the bottom of the current sheet. These phenomena are consistent with the observations of Chen et al. 2019, ApJL. The synthesized Si IV line profiles are similar to the observed one in UV bursts, the enhanced wing of the line profiles can extend to about $100$ km s$^{-1}$. The differences are significant among the numerical results with different resolutions, which indicate that the realistic magnetic diffusivity is crucial to reveal the fine structures and realistic plasmas heating in these reconnection events. Our results also show that the reconnection heating contributed by ambipolar diffusion in the low chromosphere around the temperature minimum region is not efficient

An evolutionary algorithm with double-level archives for multiobjective optimization

Existing multiobjective evolutionary algorithms (MOEAs) tackle a multiobjective problem either as a whole or as several decomposed single-objective sub-problems. Though the problem decomposition approach generally converges faster through optimizing all the sub-problems simultaneously, there are two issues not fully addressed, i.e., distribution of solutions often depends on a priori problem decomposition, and the lack of population diversity among sub-problems. In this paper, a MOEA with double-level archives is developed. The algorithm takes advantages of both the multiobjective-problemlevel and the sub-problem-level approaches by introducing two types of archives, i.e., the global archive and the sub-archive. In each generation, self-reproduction with the global archive and cross-reproduction between the global archive and sub-archives both breed new individuals. The global archive and sub-archives communicate through cross-reproduction, and are updated using the reproduced individuals. Such a framework thus retains fast convergence, and at the same time handles solution distribution along Pareto front (PF) with scalability. To test the performance of the proposed algorithm, experiments are conducted on both the widely used benchmarks and a set of truly disconnected problems. The results verify that, compared with state-of-the-art MOEAs, the proposed algorithm offers competitive advantages in distance to the PF, solution coverage, and search speed

Phosphorous-containing oxygen-deficient cobalt molybdate as an advanced electrode material for supercapacitors

The intrinsically poor electrical conductivity and insufficient number of electrochemically active sites of transition-metal oxides hamper their wide application in high-performance supercapacitors. Herein, we demonstrate an effective strategy of creating phosphorus-containing cobalt molybdate (CoMoO4) with oxygen vacancies (P-CoMoO4-x) on nickel foam for use as a supercapacitor electrode. Experimental analyses and theoretical calculations reveal that the electronic structure of P-CoMoO4-x can be efficiently modulated by incorporating P heteroatoms and O vacancies, thereby simultaneously reducing the energy band gap and increasing electrical conductivity. Moreover, incorporating P into P-CoMoO4-x weakens the Co-O bond energy and induces the low oxidation states of molybdenum species, facilitating surface redox chemistry and improving electrochemical performance. Accordingly, the optimized P-CoMoO4-x electrode exhibits a high specific capacity of 1368 C g−1 at a current density of 2 A g−1, and it retains 95.3% of the initial capacity after 5000 cycles at a high current density of 10 A g−1. An asymmetric supercapacitor assembled with the optimized P-CoMoO4-x as positive electrode and activated carbon as negative electrode delivers a high energy density of 58 W h kg−1 at a power density of 850 W kg−1 as well as achieves excellent cycling lifespan

3-Benzyl-1-butyl­imidazo[1,2-a]benzo­thieno[3,2-d]pyrimidine-2,5(1H,3H)-dione

In the crystal structure of the title compound, C23H21N3O2S, all ring atoms of the imidazo[1,2-a]benzothieno[3,2-d]pyrimidine system are essentially coplanar and the phenyl ring is twisted with respect to it [dihedral angle = 72.60 (9)°]. The crystal packing is mainly governed by C—H⋯π hydrogen bonds and inter­molecular π–π inter­actions, with inter­planar distances of 3.54 (1) and 3.56 (1) Å, and with distances between adjacent ring centroids of 3.72 (1) and 3.80 (1) Å. The three terminal C atoms of the butyl group are disordered over two positions; the site occupancy factors are ca 0.6 and 0.4

Effect of Tai Chi exercise for hypertension: a meta-analysis of randomized controlled trials

Objectives: We designed this study to evaluate the effect of Tai Chi exercise for hypertension patients. Methods: RCTs designed to evaluate the effect of Tai Chi exercise for hypertension patients were searched from Science Direct, EBSCO, Pub Med, CNKI and Wanfang databases. Results: The meta-analysis found that (ATC) the SBP (WMD = 13.19 mmHg; 95%CI: 11.52 to 14.87; P < 0.0001) and DBP (WMD = 8.92 mmHg; 95% CI: 7.94 to 9.90; P< 0.0001) can be significantly reduced after Tai Chi exercise compared to before Tai Chi exercise (BTC). ATC significantly improved the content of NO (WMD =−7.98mmol/L; 95%CI: −10.63 to −5.33; P < 0.0001), and decreased the content of TG (WMD =0.22mmol/ml; 95%CI: 0.06 to 0.38; P =0.006) and LDL-C (WMD =0.20mmol/ml; 95%CI: 0.13 to 0.26; P < 0.0001). There was no obvious difference between ATC and BTC on HR (WMD = 1.64; 95%CI: −0.51 to 3.97; P =0.14), TC (WMD = −0.03mmol/ml; 95%CI: −0.22 to 0.17; P =0.80) and HDL-C (WMD =−0.04 mmol/ml; 95%CI: −0.09 to 0.01; P =0.13). Conclusions: As a valid treatment for hypertension patients, Tai Chi exercise can decrease SBP, DBP, TG, LDL-C and increase NO

SHEARING BEHAVIOR OF STRUCTURAL INSULATED PANEL WALL SHELLED WITH BAMBOO SCRIMBER

In this study, shearing behavior of a structural insulated panel (SIP) wall, which consisted of a Styrofoam core board, shell panel of bamboo scrimber, and frame of Spruce–Pine–Fir dimension lumber, was tested under monotonic and cyclic loads. Results showed that the SIP wall failed at similar positions under two loading modes, although more serious destruction occurred under cyclic than monotonic load. There was a linear relationship between load and displacement at the initial loading stage, which indicated that the wall worked under the elastic state. At a later loading stage, bearing capacity and rigidity decreased as a result of wall slip. Shearing strength under monotonic and cyclic loads was 20.0 and 15.8 kNm-1, respectively, which met the requirement of the standard code for design of timber structures. Energy consumption of the SIP wall covered with bamboo scrimber was 11,556.6 Jm-1

New insight into the effect of fluorine doping and oxygen vacancies on electrochemical performance of Co2MnO4 for flexible quasi-solid-state asymmetric supercapacitors

Anion doping and oxygen-defect creation have been extensively employed to modify the electronic properties and increase concentration of electrochemically active sites of electrode materials for electrical energy storage technologies; however, comprehensive study of the roles of anion doping and oxygen vacancy on the enhancement of electrochemical performance is not clear. Herein, we provide new insight into the effect of fluorine dopant and oxygen vacancy on electrochemical performance of fluorine-doped oxygen-deficient Co2MnO4 (F-Co2MnO4-x) nanowires grown on carbon fiber (CF) as advanced electrode materials for supercapacitor. An experimental and theoretical study reveals that the structural and electronic properties in F-Co2MnO4-x is effectively tuned by introducing F dopants and oxygen vacancies, synergistically increasing electrical conductivity and providing rich Faradaic redox chemistry. The resultant F-Co2MnO4-x achieves a high specific capacity of 269 mA h g−1 at 1 A g−1, and superior cyclic stability with 93.2% capacity retention after 5000 cycles at 15 A g−1. A flexible quasi-solid-state asymmetric supercapacitor (ASC) is constructed with F-Co2MnO4-x/CF as the positive electrode and Fe2O3/CF as the negative electrode. The ASC device exhibits a high energy density of 64.4 W h kg−1 at a power density of 800 W kg−1. Significantly, the device yields 89.9% capacitance retention after 2000 bending tests at a bending angle ranging from 0 to 30°, demonstrating the high integration of excellent mechanical flexibility and cycling stability