909 research outputs found
Banking reforms, performance and risk in China
We investigate the impact of the banking reform started from 2005 on ownership structures in China on commercial banks’ profitability, efficiency and risk over the period 2000–2012, providing comprehensive evidence on the impact of banking reform in China. We find that banks on average tend to have higher profitability, lower risk and lower efficiency after the reforms, and the results are robust with our difference-in-difference approach. Our results also show that the Big 5 state-owned banks (SOCB) underperform banks with other types of ownership when risk is measured by non-performing loans (NPLs) over the entire study period but tend to have fewer NPLs than other banks during the post-reform period. Our results provide some supporting evidence on the ongoing banking reforms in China, suggesting that attracting strategic foreign investors and listing SOCBs on stock exchanges appear to be effective ways to help SOCBs deal with the problem of NPLs and manage their risk
Origin of High-Temperature Superconductivity in Compressed LaH
Room-temperature superconductivity has been one of the most challenging
subjects in modern physics. Recent experiments reported that lanthanum hydride
LaH (1) raises a superconducting transition temperature
up to 260 (or 215) K at high pressures around 190 (150)
GPa. Here, based on first-principles calculations, we reveal the existence of
topological Dirac-nodal-line (DNL) states in compressed LaH. Remarkably,
the DNLs protected by the combined inversion and time-reversal symmetry and the
rotation symmetry create a van Hove singularity (vHs) near the Fermi energy,
giving rise to large electronic density of states. Contrasting with other La
hydrides containing cationic La and anionic H atoms, LaH shows a
peculiar characteristic of electrical charges with anionic La and both cationic
and anionic H species, caused by a strong hybridization of the La and H
orbitals. We find that a large number of electronic states at the vHs are
strongly coupled to the H-derived high-frequency phonon modes that are induced
via the unusual, intricate bonding network of LaH, thereby yielding a
high . Our findings not only elucidate the microscopic origin of the
observed high- BCS-type superconductivity in LaH, but also
pave the route for achieving room-temperature topological superconductors in
compressed hydrogen-rich compounds.Comment: 9 pages, 11 figure
Heavy Bino and Slepton for Muon g-2 Anomaly
In light of very recent E989 experimental result, we investigate the
possibility that heavy sparticles explain the muon g-2 anomaly. We focus on the
bino-smuon loop in an effective SUSY scenario, where a light gravitino plays
the role of dark matter and other sparticles are heavy. Due to the enhancement
of left-right mixing of smuons by heavy higgsinos, the contribution of
bino-smuon loop can sizably increase the prediction of muon g-2 to the
experimental value. Under collider and vacuum stability constraints, we find
that TeV scale bino and smuon can still account for the new muon g-2 anomaly.
The implications for LHC phenomenology are also discussed.Comment: 10 pages,1 figure;Published in:Nucl.Phys.B 969(2021)115481,add some
discussions and references, matches published versio
Effects of the wide-body suspension bridge auxiliary structure on flutter characteristics by CFD
This paper is focused on the CFD numerical simulation of flutter characteristics of the wide-body flat steel box girder of Chongqing Cuntan Yangtze Bridge. The specific influence on the aerodynamic performance and flutter critical wind velocity have been studied by setting different railing ventilation rates. The results show that: the subsidiary structures of the main beam have an adverse effect on the stability of bridge flutter. The ventilation rate of the railings affects the flutter derivatives and the critical wind speed of the flutter
MODELLING AND DYNAMIC ANALYSIS OF THREE-DIRECTION GRID PRESTRESSED RETICULATED MEGA-STRUCTURE
In this paper, the generation way of three-direction grid prestressed reticulated mega- structure is studied, and the three-direction grid prestressed reticulated mega-structure composite joint specific formation ideas are proposed. The important control parameters of three-direction grid prestressed reticulated mega-structure are determined, and the geometric modelling method of hexagon across the middle joint and octagon across the side joint is proposed. Coordinate formula of hexagonal and octagonal joints are derived to ensure reasonable grid arrangement and uniform stress distribution of the structure. Combined with the geometric parameters of the mega grid, a new method for creating the geometric model of three-direction grid prestressed mega reticulated structure is realized. The quadrangular pyramid space grid structure with the same length, span, rise and grid size and the three-direction grid prestressed grid structure are calculated, and the advantages of three-direction grid prestressed grid structure in dynamic performance are compared and analyzed
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