检索结果-南通市图书馆

An ultraviolet to visible scheme to estimate chromophoric dissolved organic matter absorption in a Case-2 water from remote sensing reflectance

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2020年第2期14卷 384-400页

作者： xia lei Jiayi PAN Adam DEVLIN Institute of Space and Earth Information Science The Chinese University of Hong KongHong KongChina School of Geography and Environment Jiangxi Normal UniversityNanchang 330022China

In a typical Case-2 coastal water environment(here,the Pearl River Estuary(PRE),China),chromophoric dissolved organic matter(CDOM)and suspended particulates dominate the water optical properties,and CDOM fluorescence contributes considerably to surface water *** this paper,an ultraviolet(UV)to visible scheme to retrieve CDOM absorption(ag)is developed based on a set of in situ ***,the CDOM UV absorption and spectral slope(Sg)are derived directly from the visible remote sensing reflectance;then the Sg is extrapolated to obtain the spectrum from UV to visible spectral *** algorithm performs well,with an overall mean absolute percent difference(MAPD)of^30%,~5%and^6%for the estimation of ag in 250–450 nm,Sg over 250–400 nm,and 250–700 nm,*** effectiveness and stability of the algorithm is further demonstrated in capturing the distribution pattern of CDOM absorption in the PRE from satellite ocean color imagery with multiple spatial and spectral resolution,namely:the Visible Infrared Imaging Radiometer Suite(VIIRS)(750 m/Multispectral),the Ocean and Land Color Instrument(OLCI)(300 m/Multispectral),the Hyperspectral Imager for the Coastal Ocean(HICO)(100 m/Hyperspectral),and the Landsat 8 Operational Land Imager(OLI)(30 m/Multispectral).The UV to visible scheme can benefit the CDOM absorption estimation in two aspects:1)it is free from the disturbance of suspended matter;2)it avoids uncertainties caused by the low signalto-noise ratio(SNR)of ag measurements in the visible *** algorithm is effective in revealing multiple scales of variation of CDOM absorption from ocean color observations.

关键词： Chromophoric dissolved organic matter ocean color remote sensing Pearl River Estuary ultraviolet

Integrating of metal-organic framework UiO-66-NH2 and cellulose nanofibers mat for high-performance adsorption of dye rose bengal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2022年第9期16卷 1387-1398页

作者： Yuyao Han lei xia Xupin Zhuang Yuxia Liang State Key Laboratory of Separation Membranes and Membrane Processes National Center for International Joint Research on Separation MembranesTiangong UniversityTianjin 300387China School of Textile Science and Engineering Tiangong UniversityTianjin 300387China School of Mathematical Sciences Tianjin Normal UniversityTianjin 300387China

UiO-66-NH2 is an efficient material for removing pollutants from wastewater due to its high specific surface area,high porosity and water ***,recycling them from wastewater is *** this study,the cellulose nanofibers mat deacetylated from cellulose acetate nanofibers were used to combine with UiO-66-NH_(2)by the method of in-situ growth to remove the toxic dye,rose *** to previous work,the prepared composite could not only provide ease of separation of UiO-66-NH_(2)from the water after adsorption but also demonstrate better adsorption capacity(683 mg∙g‒1(T=25°C,pH=3))than that of the simple UiO-66-NH_(2)(309.6 mg∙g^(‒1)(T=25℃,pH=3)).Through the analysis of adsorption kinetics and isotherms,the adsorption for rose bengal is mainly suitable for the pseudo-second-order kinetic model and Freundlich ***,the relevant research revealed that the main adsorption mechanism of the composite was electrostatic interaction,hydrogen bonding andπ–π***,the approach depicts an efficient model for integrating metal-organic frameworks on cellulose nanofibers to improve metal-organic framework recovery performance with potentially broad applications.

关键词： UiO-66-NH_(2) cellulose nanofibers rose bengal adsorption mechanism

Kinetics and thermal stability of the Ni_(62)Nb_(38–x)Ta_x(x=5, 10, 15,20 and 25) bulk metallic glasses

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2017年第7期60卷 70-75页

作者： MengKe He Yi Zhang lei xia Peng Yu College of Physics and Electronic Engineering Chongqing Normal University School of Communication & Information Engineering University of Electronic Science and Technology of China

We studied thermal stability and its relationship to the glass-forming ability （GFA） of the Ni62Nb38-xTax （x=5, 10, 15, 20, 25） bulk metallic glasses （BMG） fi＇om a kinetic point of view. By fitting the heating-rate dependence of glass transition temperature （Tgonsct） and crystallization temperatures （Txonset and Txpcak） of the Ni62Nb38_xTax BMG using the Vogel-Fulcher-Tammann （VFT） equation, we obtained the ideal glass transition and crystallization temperatures （Tg0 and Tx2） and the fragility parameter （m）, and also constructed continuous heating transition （CHT） diagrams for crystallization of the BMG. The CHT diagrams of the BMG indicate enhanced thermal stability by Ta addition; the Tg~ as well as the Tx~ also illustrates this improved stability limit. The compositional dependence of m, which agrees well with that of the reduced glass-transition temperature, indicates a strong correlation between liquid fragility and glass-forming ability in the present alloy system. These results provide new evidence for understanding thermal stability, liquid fragility, and GFA in BMG.

关键词： bulk metallic glasses thermal stability kinetics glass-forming ability

Coordinated Planning for Fast Charging Stations and Distribution Networks Based on an Improved Flow Capture Location Model

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第4期9卷 1505-1516页

作者： Shiqu xiao xia lei Tao Huang xiang Wang School of Electrical Engineering and Electronic Information Xihua UniversityChengdu 610039China. Department Ingegneria Elettrica Politecnico Di TorinoTorino 10129Italy

The increasing penetration of plug-in electric vehi-cles(PEVs)should lead to a significant reduction in greenhouse gas ***,the development of PEVs is limited by the lack of charging facilities,which is constrained by the coupled transportation-distribution *** paper presents a stochastic bi-level model for the optimal allocation of fast charging stations(FCSs)and distribution network expansion planning(DNEP).First,a sequential capacitated flow-capturing location-allocation model(SCFCLM)is proposed at the lower level to optimize the allocation of FCSs on the transportation ***-Carlo simulation(MCS)is utilized to estimate daily charging load ***,we propose an economic model for DNEP at the upper level,and the chance constrained method is employed to relax power flow constraints to address the uncertainties of *** experiments are conducted to illustrate the proposed planning *** influences of the flow capturing sequence and relaxed confidence level on the PEV charging load,FCS planning strategies and DNEP schemes are *** Terms-Coordinated planning,fast charging station,flow-capturing model,plug-in electric vehicle,stochastic bi-level model.

关键词： Coordinated planning fast charging station flow-capturing model plug-in electric vehicle stochastic bi-level model.

Error-detected N-photon cluster state generation based on the controlled-phase gate using a quantum dot in an optical microcavity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2020年第2期15卷 1-11页

作者： lei-xia Liang Yan-Yan Zheng Yuan-xia Zhang Mei Zhang Department of Physics Applied Optics Beijing Area Major LaboratoryBeijing Normal UniversityBeijing 100875China School of Physics and Electronic Information Yan’an UniversityYan’an 716000China

We propose a scheme for error-detected generation of an AT-photon cluster state with a quantum dot(QD)embedded in a single-sided optical niicrocavity(QD-cavity system).The basic structure of this scheme is an error-detected controlled-phase(C-phase)gate on the hybrid electron-photon *** this scheme,the fidelity of N-photon cluster state generation can be reached imity even if low-Q cavity and cavity leakage are *** using error detecting,the generation of an AT-photon cluster state can be performed by repeating until success,which also leads to a high success probability,compared with other schemes assisted by the QD-cavity *** error-detected generation of an N-photon cluster state in the highly controllable way may benefit on the quantum network in the future.

关键词： controlled-phase gate cluster state error-detected QD-cavity system

Aphids as models for ecological and evolutionary studies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2014年第3期21卷 247-250页

作者： xiao-lei Huang Ge-xia Qiao Key Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

Aphids （Hemiptera： Aphididae） are a group of phloemfeeding insects numbering more than 5 000 extant species（Favret, 2014a）. Most species have complex life cycles that include both asexual （viviparous parthenogenesis）and sexual reproduction. They display a high degree of intraspecific polyphenism with multiple phenotypes froman identical genotype, and they have specialized associations with their host plants （Blackman ＆ Eastop, 2000）.Some aphid species are gall-makers and even have evolved sociality with division of labor （Aoki, 1977; Stern ＆Foster, 1996）. Many aphid species are agricultural and forestry pests. They incur damage to plants and carryvector plant viruses （Blackman ＆ Eastop, 2000）. Due to their fascinating biological character and economic importance, aphids have long been popular animals for research in basic and applied biology, and are becominguseful research models for studying important questions in ecology and evolution, especially in the genomic era（Brisson ＆ Stem, 2006; Huang ＆ Qiao, 2006; Srinivasan ＆ Brisson, 2012）.

关键词： APHIDS EVOLUTION (Biology) INSECT ecology INSECT anatomy INSECTS RESEARCH

Multi-Agent Few-Shot Meta Reinforcement Learning for Trajectory Design and Channel Selection in UAV-Assisted Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2022年第4期19卷 166-176页

作者： Shiyang Zhou Yufan Cheng xia lei Huanhuan Duan National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China

Unmanned aerial vehicle(UAV)-assisted communications have been considered as a solution of aerial networking in future wireless networks due to its low-cost, high-mobility, and swift features. This paper considers a UAV-assisted downlink transmission,where UAVs are deployed as aerial base stations to serve ground users. To maximize the average transmission rate among the ground users, this paper formulates a joint optimization problem of UAV trajectory design and channel selection, which is NP-hard and non-convex. To solve the problem, we propose a multi-agent deep Q-network(MADQN) ***, the agents that the UAVs act as perform actions from their observations distributively and share the same reward. To tackle the tasks where the experience is insufficient, we propose a multi-agent meta reinforcement learning algorithm to fast adapt to the new tasks. By pretraining the tasks with similar distribution, the learning model can acquire general knowledge. Simulation results have indicated the MADQN scheme can achieve higher throughput than fixed allocation. Furthermore, our proposed multiagent meta reinforcement learning algorithm learns the new tasks much faster compared with the MADQN scheme.

关键词： UAV trajectory design channel selection MADQN meta reinforcement learning

Formation of mono-dispersed droplets with electric periodic dripping regime in electrohydrodynamic(EHD) atomization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第5期28卷 1241-1249页

作者： Zhentao Wang Qisi Wang Yaosheng Zhang Yimin Jiang lei xia School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China

The formation of controllable size and dripping frequency in electrohydrodynamic(EHD)atomization with electric periodic dripping regime are of much interest and importance because of significant and wide applications,such as micro-encapsulation and *** the present study,the experimental and theoretical works were carried out to explore droplet formation in periodic dripping regime in presence of an electric *** dimensionless electric charge carried by each droplet produced is smaller than the 50%of critical value of the Rayleigh limit,where charge-to-mass ratio of droplets was obtained through the deflection distance in the presence of an electric *** droplet in electric periodic dripping regime usually undergoes oscillating deformation,and finally forms a spherical droplet below the tip no more than ten times out diameter of *** droplet size tens of microns to one hundreds of microns decreases with an increase in applied *** the electric dripping mode,droplets size is independent of flow rate and affected by flow rate due to adsorption of surface active species in *** simplified model to predict droplets size was derived from the balance of electric,surface tension and gravity *** droplets size calculated in good agreement with the ***,the dripping frequency of droplets with rang of a few to several hundred hertz obtained from timeresolved images is highly dependent of liquid flow rate and electric *** largest dripping frequency was predicted and in reasonable agreement with the experimental *** electric periodic dripping regime drop-on-demand droplets in size and dripping frequency further our understanding on the formation of identical droplets and are beneficial to many practical applications.

关键词： Electric field Electric periodic dripping Formation Diameter Dripping frequency

Dynamics and response reshaping of nonlinear predator-prey system undergoing random abrupt disturbances

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2021年第8期42卷 1123-1134页

作者： lei xia Jiaojiao SUN Zuguang YING Ronghua HUAN Weiqiu ZHU Department of Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang UniversityHangzhou 310027China

An actual ecological predator-prey system often undergoes random environmental mutations owing to the impact of natural disasters and man-made destruction, which may destroy the balance between the species. In this paper,the stochastic dynamics of the nonlinear predator-prey system considering random environmental mutations is investigated, and a feedback control strategy is proposed to reshape the response of the predator-prey system against random abrupt environmental mutations. A delayed Markov jump system(MJS) is established to model such a predator-prey system. A novel first integral is constructed which leads to better approximation solutions of the ecosystem. Then, by applying the stochastic averaging method based on this novel first integral, the stochastic response of the predator-prey system is investigated, and an analytical feedback control is designed to reshape the response of the ecosystem from the disturbed state back to the undisturbed *** simulations finally illustrate the accuracy and effectiveness of the proposed procedure.

关键词： random excitation nonlinear dynamics reshaping control stationary probability density function(SPDF) predator-prey system