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Five-view three-dimensional reconstructionfor ultrafast dynamic imaging of pulsedradiation sources

Matter and Radiation at Extremes 2024年第2期9卷 63-73页

作者： Jianpeng Gao liang Sheng Xinyi Wang Yanhong Zhang liang Li Baojun Duan Mei Zhang Yang Li Dongwei Hei Department of Engineering Physics Tsinghua UniversityBeijing 100084China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights intothe generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of thepulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are oftenavailable for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete datamay introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction methodusing cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. Weaugment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have beencarried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns betweenadjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstructionresults and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.

关键词： frames image sources

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Strong,tough,and thermally conductive nacre-inspired boron nitride nanosheet/epoxy layered nanocomposites

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Nano Research 2024年第2期17卷 820-828页

作者： Huagao Wang Rongjian Lu Lei Li Cheng liang Jia Yan Rui liang Guoxing Sun Lei Jiang Qunfeng Cheng School of Chemistry Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of EducationBeihang UniversityBeijing 100191China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China Department of Stomatology Fifth Medical CenterChinese PLA General HospitalBeijing 100039China Department of Engineering Science Faculty of Innovation EngineeringMacao University of Science and TechnologyAvenida Wai LongTaipaMacao 999078 China Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials EngineeringUniversity of MacaoAvenida da UniversidadeTaipaMacao 999078China Institute of Energy Materials Science(IEMS) University of Shanghai for Science and TechnologyShanghai 200093China

Thermally conductive polymer nanocomposites integrated with lightweight,excellent flexural strength,and high fracture toughness(KIc)would be of great use in many ***,achieving all of these properties simultaneously remains a great *** by natural nacre,here we demonstrate a lightweight,strong,tough,and thermally conductive boron nitride nanosheet/epoxy layered(BNNEL)*** of the layered structure and enhancing the interfacial interactions through hydrogen bonding and Si–O–B covalent bonding,the resulting nacre-inspired BNNEL nanocomposites show high fracture toughness of~4.22 MPa·m^(1/2),which is 7 folds as high as pure ***,the BNNEL nanocomposites demonstrate sufficient flexural strength(~168.90 MPa,comparable to epoxy resin),while also being lightweight(~1.23 g/cm^(3)).Additionally,the BNNEL nanocomposites display a thermal conductivity(κ)of~0.47 W/(m·K)at low boron nitride nanosheet loading of 2.08 vol.%,which is 2.7 times higher than that of pure epoxy *** developed nacre-inspired strategy of layered structure design and interfacial enhancement provides an avenue for fabricating high mechanical properties and thermally conductive polymer nanocomposites.

关键词： nacre-inspiration nanocomposites flexural strength fracture toughness(KIc) thermal conductivity

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All types of base conversions allowed by base editors

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Science China(Life Sciences) 2024年第2期67卷 431-433页

作者： Shun-Qing liang Wen Xue RNA Therapeutics Institute UMass Chan Medical SchoolWorcester 01655USA Department of Molecular Cell and Cancer BiologyUMass Chan Medical SchoolWorcester 01655USA Department of Molecular Medicine UMass Chan Medical SchoolWorcester 01655USA Li Weibo Institute for Rare Diseases Research UMass Chan Medical SchoolWorcester 01655USA

Base editors(BEs) hold great promise as tools for introducing single-base-pair changes in both basic research and therapeutic applications(Rees and Liu,2018).Base editors are composed of a Cas9 nickase fused to a DNA-modifying enzyme,which chemically modifies nucleobases within a specific targeting window near the Cas9-binding site.

关键词： base bases allowed

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Probabilistic-Ellipsoid Hybrid Reliability Multi-Material Topology Optimization Method Based on Stress Constraint

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 757-792页

作者： Zibin Mao Qinghai Zhao liang Zhang College of Mechanical and Electrical Engineering Qingdao UniversityQingdao266071China National Engineering Research Center for Intelligent Electrical Vehicle Power System Qingdao UniversityQingdao266071China

This paper proposes a multi-material topology optimization method based on the hybrid reliability of the probability-ellipsoid model with stress constraint for the stochastic uncertainty and epistemic uncertainty of mechanical loads in optimization *** probabilistic model is combined with the ellipsoidal model to describe the uncertainty of mechanical *** topology optimization formula is combined with the ordered solid isotropic material with penalization(ordered-SIMP)multi-material interpolation *** stresses of all elements are integrated into a global stress measurement that approximates the maximum stress using the normalized p-norm ***,the sequential optimization and reliability assessment(SORA)is applied to transform the original uncertainty optimization problem into an equivalent deterministic topology optimization(DTO)*** response surface and sparse grid technique are combined with SORA to get accurate information on the most probable failure point(MPP).In each cycle,the equivalent topology optimization formula is updated according to the MPP information obtained in the previous *** adjoint variable method is used for deriving the sensitivity of the stress constraint and the moving asymptote method(MMA)is used to update design ***,the validity and feasibility of the method are verified by the numerical example of L-shape beam design,T-shape structure design,steering knuckle,and 3D T-shaped beam.

关键词： Stress constraint probabilistic-ellipsoid hybrid topology optimization reliability analysis multi-material design

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Stereoselective synthesis of substituted 1,3-dienes from propargylic esters: electrophilic-metal or redox catalysis?

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Science China Chemistry 2024年第5期67卷 1384-1396页

作者： Mengfu Dai liangliang Song liang-An Chen Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjing 210037China

1,3-Diene architectures are not only widely present in natural products, pharmaceuticals, and functional organic materials but also serve as versatile building blocks to furnish important functionalized molecules in synthetic chemistry due to conjugated repeating C=C units. Accordingly, various strategies to access substituted 1,3-dienes in a stereoselective manner have been developed. However, chemo-, regio-and stereoselective synthesis of highly substituted 1,3-dienes still remains elusive and challenging. Readily available propargylic esters have emerged as an appealing class of synthetic intermediates for accessing functionalized 1,3-dienes, especially challenging tri-or tetrasubstituted variants, via transition-metal catalysis, including electrophilic metal and redox neutral catalysis. This review, for the first time, systematically highlights recent advances in transitionmetal catalyzed synthesis of substituted 1,3-dienes from propargylic esters, discusses the mechanisms and synthetic utilities, and gives the remaining challenges and potential opportunities in this field.

关键词： 1 3-diene propargylic ester Lewis acid redox catalysis transition metal

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Research on Credit Default Swaps Pricing Considering Moral Hazard Incentive under Reduce-Form Model

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Journal of Systems Science and Systems Engineering 2024年第3期33卷 311-329页

作者： liang Wu Kangjie He Zhe Guo School of Mathematical Science Henan Institute of Science and TechnologyXinxiang453003China Public Front Office Department Industrial and Commercial Bank of ChinaZhengzhou450000China

Equilibrium pricing of credit default swaps(CDS)promotes efficient identification of credit risk in the market,which in turn leads to efficient allocation of ***,even when CDS have been priced in equilibrium,i.e.,when premiums are equal to anticipated payments,the moral hazard incentives of CDS buyers increase with CDS ***,it becomes an interesting research direction to study the impact of moral hazard incentives on the trading mechanism or pricing of derivatives(CDS).Most of the existing literature on the impact of moral hazard incentives in CDS pricing on derivatives trading mechanisms takes a macro perspective and focuses on the agreement risk *** literature exploring the analysis of the impact of moral hazard on the probability of agreement default from a micro perspective is not yet *** this in mind,this paper focuses on the mechanisms by which“fraud”,an extreme manifestation of micro-moral hazard incentives,affects the probability of *** paper introduces for the first time the concept of“claiming fraud”by credit protection buyers,which is different from the macro perspective of moral hazard incentives,and thus defines a specific extreme form of moral hazard ***,to address the intrinsic feature of the lack of economic explanatory power of the reduce-form model,this paper introduces a moral hazard incentive factor into the reduce-form model,and proposes a moral hazard state variable as a function of the asset value of the reference entity,which gives the reduce-form model strong economic explanatory power,and the default predictability is reduced by the description of the reduce-form *** terms of the object of study,this paper considers the issue of moral hazard incentives in the presence of claiming fraud in two reference entities to further explore the impact of moral hazard incentives on default protection at the micro level in terms of cyclic ***,based on the

关键词： Financial engineering moral hazard incentive claiming fraud reduce-form model probability of default calculation CDS pricing

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Underwater Pulse Waveform Recognition Based on Hash Aggregate Discriminant Network

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Journal of Ocean University of China 2024年第3期23卷 654-660页

作者： WANG Fangchen ZHONG Guoqiang WANG liang College of Computer Science and Technology Ocean University of ChinaQingdao 266100China College of Marine Technology Ocean University of ChinaQingdao 266100China

Underwater pulse waveform recognition is an important method for underwater object *** existing works focus on the application of traditional pattern recognition methods,which ignore the time-and space-varying characteristics in sound propagation channels and cannot easily extract valuable waveform *** propagation channels in seawater are time-and space-varying convolutional *** the extraction of the waveform features of underwater acoustic signals,the effect of high-accuracy underwater acoustic signal recognition is identified by eliminating the influence of time-and space-varying convolutional channels to the greatest extent *** propose a hash aggregate discriminative network(HADN),which combines hash learning and deep learning to minimize the time-and space-varying effects on convolutional channels and adaptively learns effective underwater waveform features to achieve high-accuracy underwater pulse waveform *** the extraction of the hash features of acoustic signals,a discrete constraint between clusters within a hash feature class is *** constraint can ensure that the influence of convolutional channels on hash features is *** addition,we design a new loss function called aggregate discriminative loss(AD-loss).The use of AD-loss and softmax-loss can increase the discriminativeness of the learned hash *** results show that on pool and ocean datasets,which were collected in pools and oceans,respectively,by using acoustic collectors,the proposed HADN performs better than other comparative models in terms of accuracy and mAP.

关键词： convolutional channel hash aggregate discriminative network aggregate discriminant loss waveform recognition

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A NEW RANDOM PACKET ACCESS PROTOCOL IN WCDMA

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Journal of Electronics(China) 2002年第3期19卷 233-240页

作者： Jiao wenhua liang Qinglin(Department of Electronics, Peking University, Beijing 100871) Department of Electronics Peking University Beijing 100871

In this paper, a new Random Packet Access Protocol (RPAP) is proposed in WCDMA systems. The new proposed RPAP can efficiently prevent unnecessary interference by stopping a transmission if it is bound to be collided with others. Throughput about the new RPAP is deliberated and analyzed. Computer simulation shows that this protocol has better throughput performance compared with conventional one currently used in WCDMA.

关键词：无线通信协议码分多址 CDMA 随机数据包

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Predicting Traffic Flow Using Dynamic Spatial-Temporal Graph Convolution Networks

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Computers, Materials & Continua 2024年第3期78卷 4343-4361页

作者： Yunchang Liu Fei Wan Chengwu liang School of Computer and Data Science Henan University of Urban ConstructionPingdingshan467036China School of Electrical and Control Engineering Henan University of Urban ConstructionPingdingshan467036China

Traffic flow prediction plays a key role in the construction of intelligent transportation ***,due to its complex spatio-temporal dependence and its uncertainty,the research becomes very *** of the existing studies are based on graph neural networks that model traffic flow graphs and try to use fixed graph structure to deal with the relationship between ***,due to the time-varying spatial correlation of the traffic network,there is no fixed node relationship,and these methods cannot effectively integrate the temporal and spatial *** paper proposes a novel temporal-spatial dynamic graph convolutional network(TSADGCN).The dynamic time warping algorithm(DTW)is introduced to calculate the similarity of traffic flow sequence among network nodes in the time dimension,and the spatiotemporal graph of traffic flow is constructed to capture the spatiotemporal characteristics and dependencies of traffic *** combining graph attention network and time attention network,a spatiotemporal convolution block is constructed to capture spatiotemporal characteristics of traffic *** on open data sets PEMSD4 and PEMSD8 show that TSADGCN has higher prediction accuracy than well-known traffic flow prediction algorithms.

关键词： Intelligent transportation graph convolutional network traffic flow DTW algorithm attention mechanism

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Pan Shuh:the founding figure of modern Chinese psychology

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Protein & Cell 2024年第4期15卷 235-238页

作者： Ligang Wang Tongqi Wei liang Wang Institute of Psychology Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of Mental Health Institute of PsychologyBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 101408China

Entering the lobby of the Institute of Psychology,Chinese Academy of Sciences,the first thing that catches the eye is the Pan Shuh *** the library,Pan Shuh’s six decades of life are displayed in the form of a life photo exhibition,representing 10 years of determination,10 years of wandering,10 years of exploration,10 years of following the path,10 years of self-improvement,and 10 years of *** six decades not only reflect the life journey of Pan Shuh,the pioneer of Chinese psychology but also serve as a microcosm of the historical development of modern Chinese psychology(Qicheng Jing,Xiaolan Fu,2011).

关键词： founding representing Shu

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