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Adaptive scale model reconstruction for radio synthesis imaging

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Research in Astronomy and Astrophysics 2021年第3期21卷 117-127页

作者： li Zhang li-gong mi Long Xu ming Zhang Dan-Yang li Xiang liu Feng Wang Yi-Fan Xiao Zhong-Zu Wu College of Big Data and Information Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesUrumqi 830011China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China College of Physics Guizhou UniversityGuiyang 550025China

A sky model from CLEAN deconvolution is a particularly effective high dynamic range reconstruction in radio astronomy,which can effectively model the sky and remove the sidelobes of the point spread function(PSF)caused by incomplete sampling in the spatial frequency *** to scale-free and multi-scale sky models,adaptive-scale sky modeling,which can model both compact and diffuse features,has been proven to have better sky modeling capabilities in narrowband simulated data,especially for large-scale features in high-sensitivity observations which are exactly one of the challenges of data processing for the Square Kilometre Array(SKA).However,adaptive scale CLEAN algorithms have not been verified by real observation data and allow negative components in the *** this paper,we propose an adaptive scale model algorithm with non-negative constraint and wideband imaging capacities,and it is applied to simulated SKA data and real observation data from the Karl *** Very Large Array(JVLA),an SKA *** show that the new algorithm can reconstruct more physical models with rich *** work is a step forward for future SKA image reconstruction and developing SKA imaging pipelines.

关键词： methods:data analysis techniques:image processing techniques:interferometric

Phase-modulated multi-foci microscopy for rapid 3D imaging

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Photonics Research 2024年第7期12卷 1548-1555页

作者： WEIQI WANG li gong ZHIWEI HUANG Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

3D imaging technology is pivotal in monitoring the functional dynamics and morphological alterations in living cells and ***,conventional volumetric imaging associated with mechanical z-scanning encounters challenges in limited 3D imaging speed with inertial ***,we present a unique phase-modulated multifoci microscopy (PM^(3)) technique to achieve snapshot 3D imaging with the advantages of extended imaging depths and adjustable imaging intervals between each focus in a rapid *** accomplish the tasks,we utilize a spatial light modulator (SLM) to encode the phases of the scattered or fluorescence light emanating from a volumetric sample and then project the multiple-depth images of the sample onto a single charge-coupled device camera for rapid 3D *** demonstrate that the PM^(3)technique provides~55-fold improvement in imaging depth in polystyrene beads phantom compared to the depth of field of the objective lens ***^(3)also enables the real-time monitoring of Brownian motion of fluorescent beads in water at a 15 Hz volume *** precisely manipulating the phase of scattered light on the SLM,PM^(3)can pinpoint the specific depth information in living zebrafish and rapidly observe the 3D dynamic processes of blood flow in the zebrafish *** work shows that the PM^(3)technique developed is robust and versatile for fast 3D dynamic imaging in biological and biomedical systems.

关键词： alterations scattered beads

Time-of-flight resolved stimulated Raman scattering microscopy using counter-propagating ultraslow Bessel light bullets generation

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light(Science & Applications) 2024年第7期13卷 1427-1440页

作者： Shulang lin li gong Zhiwei Huang Optical Bioimaging Laboratory Department of Biomedical EngineeringCollege of Design and EngineeringNational University of SingaporeSingapore 117576Singapore

We present a novel time-of-flight resolved Bessel light bullet-enabled stimulated Raman scattering(B2-SRS)microscopy for deeper tissue 3D chemical imaging with high resolution without a need for mechanical *** accomplish the tasks,we conceive a unique method to enable optical sectioning by generating the counterpropagating pump and Stokes Bessel light bullets in the sample,in which the group velocities of the Bessel light bullets are made ultraslow(e.g.,vg≈0.1c)and tunable by introducing programmable angular dispersions with a spatial light *** theoretically analyze the working principle of the collinear multicolor Bessel light bullet generations and velocity controls with the relative time-of-flight resolved detection for SRS 3D deep tissue *** have also built the B2-SRS imaging system and present the first demonstration of B2-SRS microscopy with Bessel light bullets for 3D chemical imaging in a variety of samples(e.g.,polymer bead phantoms,biological samples such as spring onion tissue and porcine brain)with high *** B2-SRS technique provides a>2-fold improvement in imaging depth in porcine brain tissue compared to conventional SRS *** method of optical sectioning in tissue using counter-propagating ultraslow Bessel light bullets developed in B2-SRS is generic and easy to perform and can be readily extended to other nonlinear optical imaging modalities to advance 3D microscopic imaging in biological and biomedical systems and beyond.

关键词： Bessel resolved propagating

Strategies of selective electroreduction of aqueous nitrate to N_(2) in chloride-free system:A critical review

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Green Energy & Environment 2024年第2期9卷 198-216页

作者： Fukuan li Weizhe Zhang Peng Zhang Ao gong Kexun li College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China

Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) *** reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) ***,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several *** this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,*** summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are ***,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.

关键词： Nitrate Chloride Electroreduction Selectivity Nitrogen

Adaptive scale model reconstruction for radio synthesis imaging

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Research in Astronomy and Astrophysics 2021年第3期21卷 119-129页

作者：张利g li-gong mi Long Xu ming Zhang Dan-Yang li Xiang liu Feng Wang Yi-Fan Xiao Zhong-Zu Wu College of Big Data and Information Engineering Guizhou University Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Xinjiang Astronomical Observatory Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences Center for Astrophysics Guangzhou University College of Physics Guizhou University

A sky model from CLEAN deconvolution is a particularly effective high dynamic range reconstruction in radio astronomy,which can effectively model the sky and remove the sidelobes of the point spread function(PSF) caused by incomplete sampling in the spatial frequency *** to scale-free and multi-scale sky models,adaptive-scale sky modeling,which can model both compact and diffuse features,has been proven to have better sky modeling capabilities in narrowband simulated data,especially for large-scale features in high-sensitivity observations which are exactly one of the challenges of data processing for the Square Kilometre Array(SKA).However,adaptive scale CLEAN algorithms have not been verified by real observation data and allow negative components in the *** this paper,we propose an adaptive scale model algorithm with non-negative constraint and wideband imaging capacities,and it is applied to simulated SKA data and real observation data from the Karl *** Very Large Array(JVLA),an SKA *** show that the new algorithm can reconstruct more physical models with rich *** work is a step forward for future SKA image reconstruction and developing SKA imaging pipelines.

关键词： methods data analysis techniques image processing techniques interferometric

From risk control to resilience: developments and trends of urban roads designed as surface flood passages to cope with extreme storms

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 103-120页

作者： Zhiyu Shao Yuexin li Huafeng gong Hongxiang Chai College of Environment and Ecology Chongqing UniversityChongqing 400030China Key Laboratory of Ecological Environment of ministry of Education of Three Gorges Reservoir Area Chongqing UniversityChongqing 400030China T.Y.lin International Engineering Consulting(China)Co.Ltd. Chongqing 400045China

Urban roads can be designated as surface flood passages to transport excess runoff during extreme storms, thereby preventing local flooding, which is known as the major drainage system. However, this practice poses significant risks, including human loss and property damage, due to the high flow rate and velocity carried by roads. Moreover, urban roads with low flood-resilience may significantly hamper the transportation function during severe storms, leading to dysfunction of the city. Therefore, there is an urgent need to transform risk-oriented flood passages into resilient urban road-based flood passages. This paper presents a systematic review of existing methodologies in designing a road network-based flood passage system, along with the discussion of new technologies to enhance system resilience. The study also addresses current knowledge gaps and future directions. The results indicate that flood management measures based on the urban road network should integrate accessibility assessment, lifeline and emergency planning to ensure human well-being outcomes. Furthermore, the special needs and features of vulnerable groups must be taken into serious consideration during the planning stage. In addition, a data-driven approach is recommended to facilitate real-time management and evaluate future works.

关键词： Major drainage Flood mitigation Resilient city Stormwater model Urban flooding

Effect of boundary conditions on shakedown analysis of heterogeneous materials

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen gong Yinghao NIE Gengdong CHENG Kai li State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under ***, utilizing PBCs to

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

Developing a reliable route protocol for mobile self-organization networks

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High-Confidence Computing

High-Confidence Computing 2024年第3期4卷 1-12页

作者： Shaohu li Bei gong Faculty of Information Technology Beijing University Of TechnologyBeijing 100124China

Mobile ad hoc networks(MANETs),which correspond to a novel wireless technology,are widely used in Internet of Things(IoT)systems such as drones,wireless sensor networks,and military or disaster relief *** the perspective of communication and data collection,the success rate of collaborations between nodes in mobile ad hoc networks and reliability of data collection mainly depend on whether the nodes in the network operate normally,namely,according to the established network ***,mobile ad hoc networks are vulnerable to attacks targeting transmission channels and nodes owing to their dynamic evolution,openness,and distributed ***,during the network operation,it is necessary to classify and detect the behavior and characteristics of each ***,most existing research only analyzes and considers responses against a single or small number of *** address these issues,this article first systematically analyzed and classified common active attacks in ***,a node trust model was proposed based on the characteristics of various attacks;subsequently,a new secure routing protocol,namely,TC-AODV,was *** protocol has minimal effect on the original communication dynamics and can effectively deal with Packet drop,wormhole,Session hijacking,and other main attacks in *** NS3 simulation results show that the proposed routing protocol attains good transmission performance,can effectively identify various attacks and bypass malicious nodes,and securely complete the communication process.

关键词： Mobile ad hoc networks AODV Trust level Secure routing protocol Reliable path

Seismic and vibration control of segmented isolation layer in underground structure-diaphragm wall system

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Underground Space 2024年第6期19卷 72-86页

作者： Zhidong Gao mingbo li mi Zhao Xiuli Du Key Laboratory of Urban Security and Disaster Engineering of ministry of Education Beijing University of TechnologyBeijing 100124China Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China

In this paper,a seismic and vibration reduction measure of subway station is developed by setting a segmented isolation layer between the sidewall of structure and the diaphragm *** segmented isolation layer consists of a rigid layer and a flexible *** rigid layer is installed at the joint section between the structural sidewall and slab,and the flexible layer is installed at the remaining sections.A diaphragm wall-segmented isolation layer-subway station structure system is *** and vibration control performance of the diaphragm wall-segmented isolation layer-subway station structure system is evaluated by the detailed numerical ***,a three-dimensional nonlinear time-history analysis is carried out to study the seismic response of the station structure by considering the effect of different earthquake motions and stiffness of segmented isolation ***,the vibration response of site under training loading is also studied by considering the influence of different train velocities and stiffness of the segmented isolation *** results demonstrate that the diaphragm wall-segmented isolation layer-subway station structure system can not only effectively reduce the lateral deformation of station structure,but also reduce the tensile damage of the roof *** the other hand,the developed reduction measure can also significantly reduce the vertical peak displacements of site under training loading.

关键词： Subway station Diaphragm wall Segmented isolation layer Seismic response Train vibration