Influence of typhoon MITAG on the Kuroshio intrusion in the Luzon Strait during early fall 2019

Typhoons in the western Pacific have a significant impact on the transport of heat,salt and particles through the Luzon Strait.However,there are very limited field observations of this impact because of extreme difficulties and even dangers for ship-based measurements during the rough weather.Here,we present the preliminary results from analyzing a dataset collected by a glider deployed west of the Luzon Strait a few days prior to the arrival of typhoon MITAG.The gilder data revealed an abnormally salinity(>34.8)subsurface water apparently sourced from Kuroshio intrusion during the typhoon.When typhoon MITAG traveled on the east of the Luzon Strait,the positive wind stress curl strengthened the cyclonic eddy and weakened the anti-cyclonic eddy.This led to a slowdown of Kuroshio and made its intrusion easier.The main axis of the Kuroshio at the northern part of the strait shifted westward after the typhoon and did not return to its original position until a week later.The Ekman transport from persistent northerly wind of typhoon MITAG was significant,but its importance in enhancing the Kuroshio intrusion is only secondary relative to the eddies variations.

Topological laser on square lattice with gain–loss-induced higher-order corner modes

We investigate the higher-order topological laser in the two-dimensional(2D) coupled-cavity array. By adding staggered on-site gain and loss to the 2D Hermitian array with a trivial phase, the system will emerge degenerate topological corner modes, which are protected by bulk band gap. For such a non-Hermitian model, by adjusting the parameters of the system and introducing the pumping into the cavity at the corner, a single-mode lasing with topological protection emerges.Furthermore, single-mode lasing exists over a wide range of pumping strengths. No matter where the cavity is initially stimulated, after enough time evolution, all the cavities belonging to the topological corner mode can emit a stable laser.

Evaluation of the submarine debris-flow hazard risks to planned subsea pipeline systems: a case study in the Qiongdongnan Basin, South China Sea

The ever-increasing deepwater oil and gas development in the Qiongdongnan Basin,South China Sea has initiated the need to evaluate submarine debris-flow hazard risks to seafloor infrastructures.This paper presents a case study on evaluating the debris-flow hazard risks to the planned pipeline systems in this region.We used a numerical model to perform simulations to support this quantitative evaluation.First,one relict failure interpreted across the development site was simulated.The back-analysis modeling was used to validate the applicability of the rheological parameters.Then,this model was applied to forecast the runout behaviors of future debris flows originating from the unstable upslope regions considered to be the most critical to the pipeline systems surrounding the Manifolds A and B.The model results showed that the potential debris-flow hazard risks rely on the location of structures and the selection of rheological parameters.For the Manifold B and connected pipeline systems,because of their remote distances away from unstable canyon flanks,the potential debris flows impose few risks.However,the pipeline systems around the Manifold A are exposed to significant hazard risks from future debris flows with selected rheological parameters.These results are beneficial for the design of a more resilient pipeline route in consideration of future debris-flow hazard risks.

Influence of driving ways on measurement of relative phase in a two-atoms cavity system

We study the influence of driving ways on the interaction in a two-atoms cavity quantum electrodynamics system.The results show that driving ways can induce different excitation pathways.We show two kinds of significantly different excitation spectrums under two ways:driving cavity and driving atoms.We demonstrate that driving atoms can be considered as a method to obtain the position information of atoms.This research has very practical application values on obtaining the position information of atoms in a cavity.

Nonlinear coherent perfect photon absorber in asymmetrical atom–nanowires coupling system

Coherent perfect absorption provides a method of light-controlling-light and has practical applications in optical communications. Recently, a cavity-based nonlinear perfect photon absorption extends the coherent perfect absorber（CPA）beyond the linear regime. As nanowire-based system is a more competitive candidate for full-optical device, we introduce a nonlinear CPA in the single two-level atom–nanowires coupling system in this work. Nonlinear input–output relations are derived analytically, and three contributions of atomic saturation nonlinearity are explicit. The consociation of optical nonlinearity and destructive interference makes it feasible to fabricate a nonlinear monoatomic CPA. Our results also indicate that a nonlinear system may work linearly even when the incoming lights are not weak any more. Our findings show promising applications in full-optical devices.

Manipulation of nonreciprocal unconventional photon blockade in a cavity-driven system composed of an asymmetrical cavity and two atoms with weak dipole–dipole interaction

We present a work of manipulating collective unconventional photon blockade(UCPB)and nonreciprocal UCPB(NUCPB)in a cavity-driven system composed of an asymmetrical single-mode cavity and two interacting identical twolevel atoms(TLAs).When the atoms do not interact directly,the frequency and intensity restrictions of collective UCPB can be specified,and a giant NUCPB exists due to the splitting of optimal atom–cavity coupling strength in proper parameter regime.However,if a weak atom–atom interaction which provides a new and feeble quantum interference pathway to UCPB is taken into account,two restrictions of UCPB are combined complexly,which are rigorous to be matched simultaneously.Due to the push-and-pull effect induced by weak dipole–dipole interaction,the UCPB regime is compressed more or less.NUCPB is improved as a higher contrast is present when the two complex UCPB restrictions are matched,while it is suppressed when the restrictions are mismatched.In general,whether NUCPB is suppressed or promoted depends on its working parameters.Our findings show a prospective access to produce giant quantum nonreciprocity by a couple of weakly interacting atoms.

Boosting spring runoff into the sea by reservoir regulation and its potential for estuarine fishery recovery

With global surge in reservoir construction over the past decades,river systems worldwide have been profoundly fragmented.Consequently,flow manipulation by reservoirs has altered the natural hydrological processes,resulting in extensive modifications of fluvial-marine ecosystems.Mitigating the adverse ecological consequences of reservoirs has become a global concern and has garnered increasing attention.The Yellow River,as one of the most extensively manipulated river systems globally,has experienced substantial changes in the amount and timing of water discharge due to the presence of numerous reservoirs scattered throughout its catchment area.These alterations have caused physicochemical changes in the estuary and subsequent modifications to the estuarine ecosystem.In recent years,the Yellow River Conservancy Committee initiated the release of water through the Xiaolangdi Dam during the major spawning period of fisheries,specifically in the spring,with the aim of improving the estuarine ecological environment.From 2011 to 2020,a total of 84.05 km^(3)of water was discharged from the Xiaolangdi Reservoir during spring seasons,of which 40%(33.16 km^(3))constituted water impounded within the reservoir during preceding months.Correspondingly,the spring water discharge from the Yellow River to the sea increased significantly from 1.50 km^(3)/yr to 3.46 km^(3)/yr in the past decade,leading to a decrease in estuarine salinity by 1.6 PSU.The estuarine fishery resources,such as fish eggs in the Yellow River estuary,have demonstrated evident improvement.The reservoir regulation in the Yellow River,which has successfully enhanced spring water discharge and subsequently restored estuarine fishery resources,presents an effective attempt for mitigating the adverse ecological effects associated with reservoirs.

Nonreciprocal single-photon scattering mediated by a drivenΛ-type three-level giant atom

A waveguide-QED with giant atoms,which is capable of accessing various limits of a small one,provides a new paradigm to study photon scatterings.Thus,how to achieve nonreciprocal photon transmissions via such a giant atom setup is highly desirable.In this study,the nonreciprocal single-photon scattering characteristics of a double-drivenΛ-type three-level giant atom,where one of the transition couples to a 1D waveguide at two separate points,and the other is driven by two coherent driving fields,are investigated.It is found that a frequency-tunable single-photon diode with an ideal contrast ratio can be achieved by properly manipulating the local coupling phases between the giant atom and the waveguide,the accumulation phase between the two waveguide coupling points,the Rabi frequencies and phase difference of the two driven fields.Compared to the previous single driving schemes,on the one hand,the presence of the second driving field can provide more tunable parameters to manipulate the nonreciprocal single-photon scattering behavior.On the other hand,here perfect nonreciprocal transmission for photons with arbitrary frequencies is achievable by tuning the driving phases while the two driving fields keep on turning,which provides an alternative way to control the nonreciprocal single-photon scattering.Furthermore,the results reveal that both the location and width of each optimal nonreciprocal transmission window is also sensitive to the driving detuning,and a single-photon diode with wide or narrow bandwidth can be realized based on demand.These results may be beneficial for designing nonreciprocal single-photon devices based on a double-driven giant atom setup.

Remote determination of chromophoric dissolved organic matter in lakes, China

Chromophoric dissolved organic matter(CDOM)strongly influences the water-leaving radiance from aquatic ecosystems.In most inland waters,the remote determination of CDOM absorption presents a central challenge due to their complex optical conditions.However,identifying the temporal and spatial variability of CDOM is fundamental to the understanding of aquatic biogeo-chemical dynamics.In the present study,semi-analytical and empirical modeling approaches were used to examine CDOM absorption in four,shallow,inland water bodies using the spectral bands and sensitivities of major satellite observational systems.Of the models examined,an empirical multiband model was found to provide the highest correlation with measured CDOM absorption.The spectral characteristics of the MERIS sensors yielded the best results with respect to the other available satellite sensors.High detrital load was observed to be a major impediment to estimating CDOM absorption,while lakes with elevated phytoplankton biomass did not present similar problems.

Investigation on interfacial and electrical properties of Ge MOS capacitor with different NH_3-plasma treatment procedure

The effects of different NH3-plasma treatment procedures on interracial and electrical properties of Ge MOS capacitors with stacked gate dielectric of HtTiON/TaON were investigated. The NH3-plasma treatment was performed at different steps during fabrication of the stacked gate dielectric, i.e. before or after interlayer （TaON） deposition, or after deposition ofhigh-k dielectric （HfriON）. It was found that the excellent interface quality with an interface-state density of 4.79 × 101l eV-lcm-2 and low gate leakage current （3.43 ×10-5 A/cm2 at Vg = 1 V） could be achieved for the sample with NH3-plasma treatment directly on the Ge surface before TaON deposition. The involved mechanisms are attributed to the fact that the NH3-plasma can directly react with the Ge surface to form more Ge-N bonds, i.e. more GeOxNy, which effectively blocks the inter-diffusion of elements and suppresses the formation of unstable GeOx interfacial layer, and also passivates oxygen vacancies and dangling bonds near/at the interface due to more N incorporation and decomposed H atoms from the NH3-plasma.

Improved interfacial properties of GaAs MOS capacitor with NH3-plasma-treated ZnON as interfacial passivation layer

The GaAs MOS capacitor was fabricated with HfTiON as high-k gate dielectric and NH3-plasma-treated ZnON as interfacial passivation layer （IPL）, and its interracial and electrical properties are investigated compared to its counterparts with ZnON IPL but no NH3-plasma treatment and without ZnON IPL and no plasma treatment. Experimental results show that low interface-state density near midgap （1.17×10^12 cm^-2eV^-1） and small gate leakage current density have been achieved for the GaAs MOS device with the stacked gate dielectric of Hf-TiON/ZnON plus NH3-plasma treatment. These improvements could be ascribed to the fact that the ZnON IPL can effectively block in-diffusion of oxygen atoms and out-diffusion of Ga and As atoms, and the NH3-plasma treatment can provide not only N atoms but also H atoms and NH radicals, which is greatly beneficial to removal of defective Ga/As oxides and As-As band, giving a high-quality ZnON/GaAs interface.