A modified three-dimensional turbulence parameterization scheme,implemented by replacing the conventional eddydiffusivity formulation with the H-gradient model,has shown good performance in representing the subgrid-sc...A modified three-dimensional turbulence parameterization scheme,implemented by replacing the conventional eddydiffusivity formulation with the H-gradient model,has shown good performance in representing the subgrid-scale(SGS)turbulent fluxes associated with convective clouds in idealized tropical cyclone(TC)simulations.To evaluate the capability of the modified scheme in simulating real TCs,two sets of simulations of TC Soudelor(2015),one with the modified scheme and the other with the original scheme,are conducted.Comparisons with observations and coarse-grained results from large eddy simulation benchmarks demonstrate that the modified scheme improves the forecasting of the intensity and structure,as well as the SGS turbulent fluxes of Soudelor.Using the modified turbulence scheme,a TC with stronger intensity,smaller size,a shallower but stronger inflow layer,and a more intense but less inclined convective updraft is simulated.The rapid intensification process and secondary eyewall features can also be captured better by the modified scheme.By analyzing the mechanism by which turbulent transport impacts the intensity and structure of TCs,it is shown that accurately representing the turbulent transport associated with convective clouds above the planetary boundary layer helps to initiate the TC spin-up process.展开更多
In big data of business service or transaction,it is impossible to provide entire information to both of services from cyber system,so some service providers made use of maliciously services to get more interests.Trus...In big data of business service or transaction,it is impossible to provide entire information to both of services from cyber system,so some service providers made use of maliciously services to get more interests.Trust management is an effective solution to deal with these malicious actions.This paper gave a trust computing model based on service-recommendation in big data.This model takes into account difference of recommendation trust between familiar node and stranger node.Thus,to ensure accuracy of recommending trust computing,paper proposed a fine-granularity similarity computing method based on the similarity of service concept domain ontology.This model is more accurate in computing trust value of cyber service nodes and prevents better cheating and attacking of malicious service nodes.Experiment results illustrated our model is effective.展开更多
Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still lim...Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still limited by issues such as low sensitivity,narrow response range,slow response speed,complex fabrication techniques,and difficulties in scaling up to large arrays.Here,we present a high-sensitivity,broadband-response,and high-speed RT THz detection strategy by utilizing a deep subwavelength metal–semiconductor–metal(MSM)structure.The spontaneously formed 2-dimensional electron gas(2DEG)at the CdTe/PbTe interface provides a superior transport channel characterized by high carrier concentration,low scattering,and high mobility.The synergy of the electromagnetic induced well effect formed in the MSM structure,and the efficient and rapid transport capabilities of the 2DEG channel give rise to an impressive performance improvement.The proposed 2DEG photodetector exhibits a broad frequency range from 22 to 519 GHz,an ultralow noise equivalent power of 3.0×10^(−14)W Hz^(−1/2)at 166 GHz,and a short response time of 6.7μs.This work provides an effective route for the development of high-performance RT THz detection strategies,paving the way for enhanced THz technology applications.展开更多
Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/...Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/THz detector based on blocked-impurity-band detecting principle.The detectors are prepared by implanting phosphorus into germanium(Ge:P),where photoresponses with a P impurity band,a self-interstitial defect band,and a vacancy-P(V-P)pair defect band are realized simultaneously.The response spectra of the detectors show ultrabroad and dual response bands in a range of 3-28μm(IR band)and 40-165μm(THz band),respectively.Additionally,a tiny mid-IR(MIR)band within 3-4.2μm is embedded in the IR band.The THz band arises from the P impurity band,whereas the IR and the MIR bands are ascribed to the two defect bands.At150 m V and 4.5 K,the peak detectivities of the three bands are obtained as 2.9×10^(12) Jones(at 3.9μm),6.8×10^(12) Jones(at 16.3μm),and 9.9×10^(12) Jones(at 116.5μm),respectively.The impressive coverage andsensitivity of the detectors are promising for applications in IR and THz detection technologies.展开更多
The impact of vertical resolution on the simulation of Typhoon Lekima(2019)is investigated using the Weather Research and Forecasting(WRF)model version 3.8.1.Results show that decreasing vertical grid spacing from app...The impact of vertical resolution on the simulation of Typhoon Lekima(2019)is investigated using the Weather Research and Forecasting(WRF)model version 3.8.1.Results show that decreasing vertical grid spacing from approximately 1000 m to 100 m above 1 km height barely influences the simulated track.However,significant differences are found in the simulated tropical cyclone(TC)structure.The simulation with the coarsest vertical resolution shows a clear double warm-core structure.The upper warm core weakens and even disappears with the increase of vertical resolution.A broader eye and a more slantwise eyewall are observed with the increase of vertical resolution due to the vertically extended lower-level and upper-level outflow,which likely results in a weaker subsidence.Vertical grid convergence is evaluated with the simulated kinetic energy(KE)spectra.As the vertical grid spacing becomes finer than 200 m,convergent KE spectra are found in both the free atmosphere and the outer core of the TC.However,sensitivity tests reveal that the grid convergence is sensitive to the choice of the planetary boundary layer scheme.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC3000803)the National Natural Science Foundation of China(Grant Nos.42375149,41975133 and 42205070)the Shanghai Pujiang Program(Grant No.22PJ1415900)。
文摘A modified three-dimensional turbulence parameterization scheme,implemented by replacing the conventional eddydiffusivity formulation with the H-gradient model,has shown good performance in representing the subgrid-scale(SGS)turbulent fluxes associated with convective clouds in idealized tropical cyclone(TC)simulations.To evaluate the capability of the modified scheme in simulating real TCs,two sets of simulations of TC Soudelor(2015),one with the modified scheme and the other with the original scheme,are conducted.Comparisons with observations and coarse-grained results from large eddy simulation benchmarks demonstrate that the modified scheme improves the forecasting of the intensity and structure,as well as the SGS turbulent fluxes of Soudelor.Using the modified turbulence scheme,a TC with stronger intensity,smaller size,a shallower but stronger inflow layer,and a more intense but less inclined convective updraft is simulated.The rapid intensification process and secondary eyewall features can also be captured better by the modified scheme.By analyzing the mechanism by which turbulent transport impacts the intensity and structure of TCs,it is shown that accurately representing the turbulent transport associated with convective clouds above the planetary boundary layer helps to initiate the TC spin-up process.
文摘In big data of business service or transaction,it is impossible to provide entire information to both of services from cyber system,so some service providers made use of maliciously services to get more interests.Trust management is an effective solution to deal with these malicious actions.This paper gave a trust computing model based on service-recommendation in big data.This model takes into account difference of recommendation trust between familiar node and stranger node.Thus,to ensure accuracy of recommending trust computing,paper proposed a fine-granularity similarity computing method based on the similarity of service concept domain ontology.This model is more accurate in computing trust value of cyber service nodes and prevents better cheating and attacking of malicious service nodes.Experiment results illustrated our model is effective.
基金supported by the National Natural Science Foundation of China(11933006,61805060,U2141240,and 62175045)National Key Research and Development Project of China(2023YFB2806700)+5 种基金Zhejiang Provincial Natural Science Foundation of China(LGF21F050001)Hangzhou Science and Technology Bureau of Zhejiang Province(TD2020002)Hangzhou Key Research and Development Program(2024SZD1A39)Research Funds of Hangzhou Institute for Advanced Study(B02006C019019 and 2022ZZ01007)Zhejiang Provincial Natural Science Foundation of China(no.LD25F040001)Hangzhou Joint Fund of the Zhejiang Provincial Natural Science Foundation of China(no.LHZQN25F050001).
文摘Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still limited by issues such as low sensitivity,narrow response range,slow response speed,complex fabrication techniques,and difficulties in scaling up to large arrays.Here,we present a high-sensitivity,broadband-response,and high-speed RT THz detection strategy by utilizing a deep subwavelength metal–semiconductor–metal(MSM)structure.The spontaneously formed 2-dimensional electron gas(2DEG)at the CdTe/PbTe interface provides a superior transport channel characterized by high carrier concentration,low scattering,and high mobility.The synergy of the electromagnetic induced well effect formed in the MSM structure,and the efficient and rapid transport capabilities of the 2DEG channel give rise to an impressive performance improvement.The proposed 2DEG photodetector exhibits a broad frequency range from 22 to 519 GHz,an ultralow noise equivalent power of 3.0×10^(−14)W Hz^(−1/2)at 166 GHz,and a short response time of 6.7μs.This work provides an effective route for the development of high-performance RT THz detection strategies,paving the way for enhanced THz technology applications.
基金National Natural Science Foundation of China(11933006,61775229,61805060,61927813)Key Research and Development Program of Zhejiang Province(2020C01120)Sino-German Science Center(GZ1580)。
文摘Broadband response is pursued in both infrared(IR)and terahertz(THz)detection technologies,which find their applications in both terrestrial and astronomical realms.Herein,we report an ultrabroadband and multiband IR/THz detector based on blocked-impurity-band detecting principle.The detectors are prepared by implanting phosphorus into germanium(Ge:P),where photoresponses with a P impurity band,a self-interstitial defect band,and a vacancy-P(V-P)pair defect band are realized simultaneously.The response spectra of the detectors show ultrabroad and dual response bands in a range of 3-28μm(IR band)and 40-165μm(THz band),respectively.Additionally,a tiny mid-IR(MIR)band within 3-4.2μm is embedded in the IR band.The THz band arises from the P impurity band,whereas the IR and the MIR bands are ascribed to the two defect bands.At150 m V and 4.5 K,the peak detectivities of the three bands are obtained as 2.9×10^(12) Jones(at 3.9μm),6.8×10^(12) Jones(at 16.3μm),and 9.9×10^(12) Jones(at 116.5μm),respectively.The impressive coverage andsensitivity of the detectors are promising for applications in IR and THz detection technologies.
基金sponsored by the Research Program from Science and Technology Committee of Shanghai(No.19dz1200101)the National Key Research and Development Program of China(No.2016YFE0109700)the National Natural Science Foundation of China(Grant No.42075012).
文摘The impact of vertical resolution on the simulation of Typhoon Lekima(2019)is investigated using the Weather Research and Forecasting(WRF)model version 3.8.1.Results show that decreasing vertical grid spacing from approximately 1000 m to 100 m above 1 km height barely influences the simulated track.However,significant differences are found in the simulated tropical cyclone(TC)structure.The simulation with the coarsest vertical resolution shows a clear double warm-core structure.The upper warm core weakens and even disappears with the increase of vertical resolution.A broader eye and a more slantwise eyewall are observed with the increase of vertical resolution due to the vertically extended lower-level and upper-level outflow,which likely results in a weaker subsidence.Vertical grid convergence is evaluated with the simulated kinetic energy(KE)spectra.As the vertical grid spacing becomes finer than 200 m,convergent KE spectra are found in both the free atmosphere and the outer core of the TC.However,sensitivity tests reveal that the grid convergence is sensitive to the choice of the planetary boundary layer scheme.
