Effects of wave-current interaction on the waves, cold-water mass and transport of diluted water in the Beibu Gulf

Wave-current interaction and its effects on the hydrodynamic environment in the Beibu Gulf(BG) have been investigated via employing the Coupled Ocean–Atmosphere–Wave–Sediment Transport(COAWST) modeling system. The model could simulate reasonable hydrodynamics in the BG when validated by various observations.Vigorous tidal currents refract the waves efficiently and make the seas off the west coast of Hainan Island be the hot spot where currents modulate the significant wave height dramatically. During summer, wave-enhanced bottom stress could weaken the near-shore component of the gulf-scale cyclonic-circulation in the BG remarkably, inducing two major corresponding adjustments: Model results reveal that the deep-layer cold water from the southern BG makes critical contribution to maintaining the cold-water mass in the northern BG Basin.However, the weakened background circulation leads to less cold water transported from the southern gulf to the northern gulf, which finally triggers a 0.2℃ warming in the cold-water mass area;In the top areas of the BG, the suppressed background circulation reduces the transport of the diluted water to the central gulf. Therefore, more freshwater could be trapped locally, which then triggers lower sea surface salinity(SSS) in the near-field and higher SSS in the far-field.

Upwelling off the west coast of Hainan Island: sensitivity to wave-mixing

The coupled ocean atmosphere wave sediment transport(COAWST)modeling system is employed to investigate the role of wave-mixing playing in the upwelling off the west coast of Hainan Island(WHU).Waves,tides and sea surface temperature(SST)are reproduced reasonably well by the model when validated by observations.Model results suggest the WHU is tidally driven.Further investigations indicate that inclusion of wave-mixing promotes the intensity of the WHU,making the simulated SST become more consistent with remote-sensed ones.Dynamically,wave-mixing facilitates the“outcrop”of more upwelled cold water,triggering stronger WHU and leading to a three-dimensional dynamical adjustment.From the perspective of time,wave-mixing contributes to establishing an earlier tidal mixing front strong enough to generate WHU and that is,WHU may occur earlier when taking wave-mixing into consideration.

Risk Measurement and Performance Evaluation of Equity Funds Based on ARMA-GARCH Family Model

There are few comprehensive studies on risk measurement and performance evaluation of stock funds in China. This paper uses the ARMA-GARCH family model to analyze the volatility characteristics of equity funds under the t-distribution and Generalized error distribution (GED), and combines CVaR, PM (Second revised sharp ratio) and CVaR-RAROC (Revised RAROC) to comprehensively evaluate equity funds risk and performance. The empirical analysis of five equity funds in China from October 28, 2010 to May 17, 2019 shows that: Comprehensive evaluation of the risk and performance of equity funds can comprehensively and effectively examine the risks and returns of equity funds, helping investors, financial institutions and regulatory agencies to more fully understand the risks and performance of equity funds.

Efficient ozone decomposition over bifunctional Co_(3)Mn-layered double hydroxide with strong electronic interaction

Ground-level ozone is one of the primary pollutants detrimental to human health and ecosystems.Catalytic ozone decomposition still suffers from low efficiency and unsatisfactory stability.In this work,we report a manganese-based layered double hydroxide catalyst(Co_(3)Mn-LDH),which exhibited a superior ozone decomposition performance with the efficiency of 100% and stability over 7 h under a GHSV of 2,000,000 mL g^(-1)h^(-1) and relative humidity of 15%.Even when the relative humidity increased to 50%,the ozone decomposition also reached 86%,which significantly exceeds as-synthesized MnO_(2) and commercial MnO_(2) in performance.The catalytic mechanism was studied by H_(2)-TPR,FT-IR and XPS.The excellent performance of Co_(3)Mn-LDH can be attributed to its abundant surface hydroxyl groups that ensured the preferentially surface enrichment of ozone,as well as the cyclic dynamic replenishment of electrons between multivalent Co^(2+)/Co^(3+),Mn^(2+)/Mn^(3+)/Mn^(4+)and oxygen species that endowed the stable ozone decomposition.This work offers new insights into the design of efficient catalysts for ozone pollution control.

Ultrathin nanobelts-assembled Chinese knot-like 3D TiO2 for fast and stable lithium storage

Nanostructured TiO2 has applications in solar cells, photocatalysts, and fast- charging, safe lithium ion batteries （LIBs）. To meet the demand of high-capacity and high-rate LIBs with TiO2-based anodes, it is important to fine-tune the nanoarchitecture using a well-controlled synthesis approach. Herein, we report a new approach that involves epitaxial growth combined with topotactic conversion to synthesize a unique type of three-dimensional （3D） TiO2 nano- architecture that is assembled by well-oriented ultrathin nanobelts. The whole nanoarchitecture displays a 3D Chinese knot-like morphology; the core consists of robust perpendicular interwoven nanobelts and the shell is made of extended nanobelts. The nanobelts oriented in three perpendicular [001]A directions facilitate Li＋ penetration and diffusion. Abundant anatase/TiO2-B interfaces provide a large amount of interfacial pseudocapacitance. A high and stable capacity of 130 mA.h.g-1 was obtained after 3,000 cycles at 10 A·g-1 （50 C）, and the high-rate property of our material was greater than that of many recently reported high-rate TiO2 anodes. Our result provides, not only a novel synthesis strategy, but also a new type of 3D anatase TiO2 anode that may be useful in developing long-lasting and fast-charging batteries.