We study the
P
cs
(
4459
)
0
recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the
D
¯
∗
Ξ
c
hadronic molecular state of either
J
P
=
1
/
2
-
or
3
.../
2
-
. Within the hadronic molecular picture, the three LHCb experiments observing
P
c
and
P
cs
states (Aaij et al., Phys Rev Lett 115:072001, 2015; Aaij et al., Phys Rev Lett 122:222001, 2019; Aaij et al.,
arXiv:2012.10380
hep-ex, 2012) can be well understood as a whole. This strongly supports the existence of hadronic molecules, whose studies can significantly improve our understanding on the construction of the subatomic world. To verify this picture, we propose to further investigate the
P
cs
(
4459
)
0
to examine whether it can be separated into two states, and to search for the
D
¯
Ξ
c
molecular state of
J
P
=
1
/
2
-
.
Increasing demand for sustainable and clean energy is calling for the next‐generation energy conversion and storage technologies such as fuel cells, water electrolyzers, CO2/N2 reduction ...electrolyzers, metal–air batteries, etc. All these electrochemical processes involve oxygen electrocatalysis. Boosting the intrinsic activity and the active‐site density through rational design of metal–organic frameworks (MOFs) and metal–organic gels (MOGs) as precursors represents a new approach toward improving oxygen electrocatalysis efficiency. MOFs/MOGs afford a broad selection of combinations between metal nodes and organic linkers and are known to produce electrocatalysts with high surface areas, variable porosity, and excellent activity after pyrolysis. Some recent studies on MOFs/MOGs for oxygen electrocatalysis and their new perspectives in synthesis, characterization, and performance are discussed. New insights on the structural and compositional design in MOF/MOG‐derived oxygen electrocatalysts are summarized. Critical challenges and future research directions are also outlined.
Boosting the intrinsic activity and the active‐site density through rational design of metal–organic frameworks (MOFs) and metal–organic gels (MOGs) as precursors represents a new approach of improving oxygen electrocatalysis efficiency. Several key compositional and structural considerations for the MOF/MOG design and new perspectives between synthesis, characterization, and performance are comprehensively discussed.
In the past decade many charmonium-like states were observed experimentally. Especially those charged charmonium-like Zc states and bottomonium-like Zb states cannot be accommodated within the naive ...quark model. These charged Zc states are good candidates of either the hidden-charm tetraquark states or molecules composed of a pair of charmed mesons. Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model. In this work, we review the current experimental progress and investigate various theoretical interpretations of these candidates of the multiquark states. We list the puzzles and theoretical challenges of these models when confronted with the experimental data. We also discuss possible future measurements which may distinguish the theoretical schemes on the underlying structures of the hidden-charm multiquark states.
Stable and efficient guided waves are essential for information transmission and processing. Recently, topological valley-contrasting materials in condensed matter systems have been revealed as ...promising infrastructures for guiding classical waves, for they can provide broadband, non-dispersive and reflection-free electromagnetic/mechanical wave transport with a high degree of freedom. In this work, by designing and manufacturing miniaturized phononic crystals on a semi-infinite substrate, we experimentally realized a valley-locked edge transport for surface acoustic waves (SAWs). Critically, original one-dimensional edge transports could be extended to quasi-two-dimensional ones by doping SAW Dirac "semimetal" layers at the boundaries. We demonstrate that SAWs in the extended topological valley-locked edges are robust against bending and wavelength-scaled defects. Also, this mechanism is configurable and robust depending on the doping, offering various on-chip acoustic manipulation, e.g., SAW routing, focusing, splitting, and converging, all flexible and high-flow. This work may promote future hybrid phononic circuits for acoustic information processing, sensing, and manipulation.
Pentaquark and Tetraquark States Liu, Yan-Rui; Chen, Hua-Xing; Chen, Wei ...
Progress in particle and nuclear physics,
July 2019, 2019-07-00, Volume:
107
Journal Article
Peer reviewed
Open access
The past seventeen years have witnessed tremendous progress on the experimental and theoretical explorations of the multiquark states. The hidden-charm and hidden-bottom multiquark systems were ...reviewed extensively in Ref. 1. In this article, we shall update the experimental and theoretical efforts on the hidden heavy flavor multiquark systems in the past three years. Especially the LHCb collaboration not only confirmed the existence of the hidden-charm pentaquarks but also provided strong evidence of the molecular picture. Besides the well-known XYZ and Pc states, we shall discuss more interesting tetraquark and pentaquark systems either with one, two, three or even four heavy quarks. Some very intriguing states include the fully heavy exotic tetraquark states QQQ̄Q̄ and doubly heavy tetraquark states QQq̄q̄, where Q is a heavy quark. The QQQ̄Q̄ states may be produced at LHC while the QQq̄q̄ system may be searched for at BelleII and LHCb. Moreover, we shall pay special attention to various theoretical schemes such as the chromomagnetic interaction (CMI), constituent quark model, meson exchange model, heavy quark and heavy diquark symmetry, QCD sum rules, Faddeev equation for the three body systems, Skyrme model and the chiral quark-soliton model, and the lattice QCD simulations. We shall emphasize the model-independent predictions of various models which are truly/closely related to Quantum Chromodynamics (QCD). For example, the chromomagnetic interaction arises from the gluon exchange which is fundamental and universal in QCD and responsible for the mixing and mass splitting of the conventional mesons and baryons within the same multiplet. The same CMI mechanism shall also be responsible for the mixing of the different color configurations and mass splittings within the multiplets in the multiquark sector. There have also accumulated many lattice QCD simulations through multiple channel scattering on the lattice in recent years, which provide deep insights into the underlying structure/dynamics of the XYZ states. In terms of the recent Pc states, the lattice simulations of the charmed baryon and anti-charmed meson scattering are badly needed. We shall also discuss some important states which may be searched for at BESIII, BelleII and LHCb in the coming years.
Organic electroactive compounds hold great potential to act as cathode material for organic sodium‐ion batteries (OSIBs) because of their environmental friendliness, sustainability, and high ...theoretical capacity. Although some organic electrodes have been developed with good performance, their practical application is still obstructed by some inherent drawbacks such as low conductivity and solubility in organic electrolytes. In addition, research on OSIBs has been mainly focused on the performance of electrodes on the material level and neglected the trade‐off relationship between the high redox potentials and specific capacities. Almost all organic cathodes used in OSIBs lack the ability to be charged first in half‐cells because of the absence of detachable sodium ions, resulting in low attractiveness when assembling full cells with hard carbon as anode. Here, this review presents several existing reaction mechanisms in OSIBs and designs of organic cathode materials. Furthermore, strategies are proposed in order to provide guidelines for improving their performance according to some critical parameters (output voltage, specific capacity, and cycle life) in potential practical OSIBs, and some accounts of organic materials assembled in full cells are summarized. Finally, the challenges and prospects of organic electrodes for OSIBs are also discussed in this review.
A comprehensive summary on how to improve the electronic performance of organic cathode materials for the potential commercial application of organic sodium‐ion batteries is presented.
Highly enantioselective 3+3 and 3+4 annulations of isatin‐derived enals with ethynylethylene carbonates and ethynyl benzoxazinanones are enabled by NHC/cooper cooperative catalysis, leading to a big ...library of spirooxindole derivatives in high structural diversity and enantioselectivity (up to 99 % ee). Both reactions represent a nicely synergistic integration of NHC and copper catalysis, in which both catalysts activate the substrates and the chiral NHC perfectly controls the stereochemistry.
All together now: A cooperative N‐heterocyclic carbene (NHC)/cooper catalytic system was developed for the diversity‐oriented synthesis of spirooxindole derivatives through enantioselective 3+3 and 3+4 annulation reactions. Highly enantioselective 3+3 and 3+4 annulations of isatin‐derived enals with ethynylethylene carbonates and ethynyl benzoxazinanones were achieved.
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