Fully open-flavor tetraquark states bcqˉsˉbc\bar{q}\bar{s} and scqˉbˉsc\bar{q}\bar{b} with JP=0+,1+J^{P}=0^{+},1^{+}

We have studied the masses for fully open-flavor tetraquark states $bc\bar{q}\bar{s}$ and $sc\bar{q}\bar{b}$ with quantum numbers $J^{P}=0^{+},1^{+}$. We systematically construct all diquark-antiquark interpolating currents and calculate the two-point correlation functions and spectral densities in the framework of QCD sum rule method. Our calculations show that the masses are about $7.1-7.2$ GeV for the $bc\bar{q}\bar{s}$ tetraquark states and $7.0-7.1$ GeV for the $sc\bar{q}\bar{b}$ tetraquarks. The masses of $bc\bar{q}\bar{s}$ tetraquarks are below the thresholds of $\bar{B}_{s}D$ and $\bar{B}_{s}^{*}D$ final states for the scalar and axial-vector channels respectively. The $sc\bar{q}\bar{b}$ tetraquark states with $J^{P}=1^{+}$ lie below the $B_{c}^{+}K^{*}$ and $B_{s}^{*}D$ thresholds. Such low masses for these possible tetraquark states indicate that they can only decay via weak interaction and thus are very narrow and stable.Comment: 17 pages, 4 figure

Dynamic response of bridge abutment to sand-rubber mixtures backfill under seismic loading conditions

China is located between the Pacific Ocean seismic belt and the Eurasian seismic belt where the seismic activity is frequent. Bridge plays a key role in transportation lifeline, but its construction and maintenance face potential seismic hazard in China, which may lead to a huge economic loss. This study investigates the dynamic response of bridge abutment to sand-rubber mixtures backfill under seismic loading conditions by finite element method. Sand-rubber mixtures is composed of waste fibers, rubber particles, sand and water with a certain mixing ratio and dry density It has been used as an anti-seismic backfill material for slopes, retaining walls, bridge structures and other geo-structures. A series of numerical simulations was carried out to evaluate the effectiveness of this new material as backfill material for bridge abutment. The seismic performance of bridge abutment with different backfill materials was analyzed with respect to settlements and accelerations of ground, foundation pile and bridge abutment. The results show that the sand-rubber mixture can be used as backfill material, and has a great potential in reducing the settlements and accelerations of ground and foundation pile

Magnetic resonance multitasking for motion-resolved quantitative cardiovascular imaging.

Quantitative cardiovascular magnetic resonance (CMR) imaging can be used to characterize fibrosis, oedema, ischaemia, inflammation and other disease conditions. However, the need to reduce artefacts arising from body motion through a combination of electrocardiography (ECG) control, respiration control, and contrast-weighting selection makes CMR exams lengthy. Here, we show that physiological motions and other dynamic processes can be conceptualized as multiple time dimensions that can be resolved via low-rank tensor imaging, allowing for motion-resolved quantitative imaging with up to four time dimensions. This continuous-acquisition approach, which we name cardiovascular MR multitasking, captures - rather than avoids - motion, relaxation and other dynamics to efficiently perform quantitative CMR without the use of ECG triggering or breath holds. We demonstrate that CMR multitasking allows for T1 mapping, T1-T2 mapping and time-resolved T1 mapping of myocardial perfusion without ECG information and/or in free-breathing conditions. CMR multitasking may provide a foundation for the development of setup-free CMR imaging for the quantitative evaluation of cardiovascular health

Experimental study on dynamic properties of sand-rubber mixtures in a small range of shearing strain amplitudes

Sand-rubber mixtures has characteristics of light weight, cheap and environmental-friendly, thereby it has a great potential to be used in geotechnical engineering for sustainable development. Dynamic properties (i.e. shear modulus and damping ratio) of sand-rubber mixtures in a small range of shearing strain amplitudes (i.e. 10-6-10-4) were investigated in this study through a series of resonant column tests. The effects of shearing strain amplitude, confining pressure and rubber content on dynamic shear modulus (G), maximum dynamic shear modulus (Gmax), damping ratio (D) and dynamic shear modulus ratio G/Gmax of the mixtures were also discussed. Based on the analyses of the relationship among confining pressure, rubber content and Gmax, an empirical formula for predicting Gmax considering the effects of confining pressure and rubber content was also proposed. The model prediction agreed with the experimental results very well