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Effects of rainfall on the weekday traffic flow in major cities of the Beijing-Tianjin-Hebei region, China, in 2021

Advances in Climate Change Research 2022年第6期13卷 858-867页

作者： ming-ming xiong Zhen-Yu HAN Bo LU Jun GUO Shu XU Yan-Juan YANG He HUANG Tianjin Climate Center Tianjin Meteorological ServiceTianjin 300074China National Climate Center China Meteorological AdministrationBeijing 100081China Tianjin Meteorological Observatory Tianjin Meteorological ServiceTianjin 300074China

Rainfall can bring uncertainties to the traffic flow and influence the normal function of urban transportation *** impact of precipitation on the urban traffic flow,especially the different impacts among cities and areas within a city,is worth ***,we analysed the impact of precipitation on the traffic flow in the urban areas of the Beijing-Tianjin-Hebei region by comparing the traffic flow in non-precipitation and rainy weather with different hourly precipitation intensities in *** increase in the travel time index(TTI)is chosen to represent the influence of precipitation on the transportation *** results show that the maximum of the average TTI increases on the city scale under various rainfall intensities by 3.3%,6.6%and 10.8%in Beijing,Tianjin and Shijiazhuang,*** general,the increase in the TTI contributed by precipitation is the greatest at morning and afternoon peak hours,and the traffic congestion degree increases with the rainfall ***,in the morning peak,afternoon peak and midday hours in Beijing and Tianjin,the influences of the weak rainfall intensity on the traffic flow are generally great,whereas the traffic congestion degree caused by heavy precipitation is relatively ***,in morning peak hours,the congestion reduction reaches approximately 2%,which may be related to the spatial difference in the impacts of precipitation on the traffic flow and the changes in people's travel intention under different rainfall *** findings can help better understand the relationship between rainfall and urban traffic flow characteristics and also potentially contribute to the development of impact-oriented climate predictions.

关键词： Rainfall intensity Urban traffic flow Beijing-Tianjin-Hebei region Auto Navi map road condition data

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新型防雨蚀抗静电涂层系统的制备

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表面技术 2018年第5期47卷 202-207页

作者：万耀明余明明熊瑜张玉忠梁璐中国航发北京航空材料研究院北京100095

目的针对高盐高湿热海洋环境下对涂层长期耐盐雾和耐湿热性能提出的更高要求,设计研制了一种新型防雨蚀抗静电涂层系统,以提高涂层系统的防雨蚀抗静电功能。方法采用新型饱和聚烯烃改性的弹性聚氨酯为基体树脂,通过研究饱和聚烯烃、导... 详细信息

目的针对高盐高湿热海洋环境下对涂层长期耐盐雾和耐湿热性能提出的更高要求,设计研制了一种新型防雨蚀抗静电涂层系统,以提高涂层系统的防雨蚀抗静电功能。方法采用新型饱和聚烯烃改性的弹性聚氨酯为基体树脂,通过研究饱和聚烯烃、导电填料的用量对涂层系统性能的影响,确定最优的配方设计。结果采用饱和聚烯烃型聚氨酯制备得到的防雨蚀抗静电涂层体系,在聚烯烃质量分数为40%时,其力学强度为21.3 MPa,断裂伸长率为385%,80℃热水浸泡19 d后,力学强度为15.8 MPa,断裂伸长率为280%,显示出优异的耐水性能。导电粉体质量分数为16%时,抗静电涂层表面电阻为4 M?/m^2。在75 d盐雾实验之后,涂层电性能依然稳定,显示良好的稳定性。并且涂层的工艺性能良好,可室温固化。结论饱和聚烯烃的引入提高了涂层的力学强度及弹性,增强了其防雨蚀冲刷性能,导电填料用量的优化提升了涂层系统的抗静电性能。此外,涂层系统的工艺性能良好,应用前景广阔。

关键词：防雨蚀抗静电涂层弹性聚氨酯饱和聚烯烃耐盐雾耐水性

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OPTIMAL ALLOCATION FOR ESTIMATING THE CORRELATION COEFFICIENT OF MORGENSTERN TYPE BIVARIATE EXPONENTIAL DISTRIBUTION BY RANKED SET SAMPLING WITH CONCOMITANT VARIABLE

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Journal of Systems Science & Complexity 2013年第2期26卷 249-260页

作者： XIE Minyu xiong ming WU ming School of Mathematics and Statistics Central China Normal University

Ranked set sample is applicable whenever ranking of a set of sample units can be done easily by a judgement method of the study variable or of the auxiliary variable. This paper considers ranked set sample based on the auxiliary variable X which is correlated with the study variable Y, where （X, Y） follows Morgenstern type bivariate exponential distribution. The authors discuss the optional allocation for unbiased estimators of the correlation coefficient p of the random variables X and Y when the auxiliary variable X is used for ranking the sample units and the study variable Y is measured for estimating the correlation coefficient. This paper first gives a class of unbiased estimators of p when the mean 0 of the study variable Y is known and obtains an essentially complete subclass of this class. Further, the optimal allocation of the unbiased estimators is found in this subclass and is proved to be Bayes, admissible, and minimax. Finally, the unbiased estimator of p under the optimal allocation in the case of known θ is reformed for estimating p in the case of unknown θ, and the reformed estimator is shown to be strongly consistent.

关键词： Concomitants of order statistic Morgenstern type bivariate exponential distribution optimal allocation ranked set sample unbiased estimator.

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GPS: graph contrastive learning via multi-scale augmented views from adversarial pooling

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Science China(Information Sciences) 2025年第1期 145-158页

作者： Wei JU Yiyang GU Zhengyang MAO Ziyue QIAO Yifang QIN Xiao LUO Hui xiong ming ZHANG School of Computer Science National Key Laboratory for Multimedia Information ProcessingPeking University Artificial Intelligence Thrust The Hong Kong University of Science and Technology Department of Computer Science University of California

Self-supervised graph representation learning has recently shown considerable promise in a range of fields, including bioinformatics and social networks. A large number of graph contrastive learning approaches have shown promising performance for representation learning on graphs, which train models by maximizing agreement between original graphs and their augmented views(i.e., positive views). Unfortunately, these methods usually involve pre-defined augmentation strategies based on the knowledge of human experts. Moreover, these strategies may fail to generate challenging positive views to provide sufficient supervision signals. In this paper, we present a novel approach named graph pooling contrast(GPS) to address these *** by the fact that graph pooling can adaptively coarsen the graph with the removal of redundancy, we rethink graph pooling and leverage it to automatically generate multi-scale positive views with varying emphasis on providing challenging positives and preserving semantics, i.e., strongly-augmented view and weakly-augmented view. Then, we incorporate both views into a joint contrastive learning framework with similarity learning and consistency learning, where our pooling module is adversarially trained with respect to the encoder for adversarial robustness. Experiments on twelve datasets on both graph classification and transfer learning tasks verify the superiority of the proposed method over its counterparts.

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Design of Flexible Films Based on Kinked Carbon Nanofibers for High Rate and Stable Potassium-Ion Storage

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Nano-Micro Letters 2022年第3期14卷 184-200页

作者： Qiaotian xiong Hongcheng He ming Zhang Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low‑Dimensional Structural Physics&Devices School of Physics and ElectronicsCollege of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082People’s Republic of China Semiconductor Technology and Application Innovation Institute of Changsha Changsha 410012People’s Republic of China

With the emergence of wearable electronics,flexible energy storage materials have been extensively studied in recent ***,most studies focus on improving the electrochemical properties,ignoring the flexible mechanism and structure design for flexible electrode materials with high rate capacities and long-time *** this study,porous,kinked,and entangled network structures are designed for highly flexible fiber *** on theoretical analysis and finite element simulation,the bending degree of the porous structure(30%porosity)increased by 192%at the *** appropriate increase in kinking degree at the meso-level and contact points in entanglement network at the macro-level are beneficial for the flexibility of fiber ***,a porous and entangled network of sulfur-/nitrogen-co-doped kinked carbon nanofibers(S/N-KCNFs)is *** nanofiber films synthesized from melamine as nitrogen sources and segmented vulcanization exhibited a porous,kinked,and entangled network structure,and the stretching degree increased several *** flexible S/N-KCNFs anode delivered a higher rate performance of 270 mAh g−1 at a current density of 2000 mA g−1 and a higher capacity retention rate of 93.3%after 2000 ***,the foldable pouch cell assembled by potassium-ion hybrid supercapacitor operated safely at large-angle bending and showed long-time stability of 88%capacity retention after 4000 *** study provides a new idea and strategy for the flexible structure design of high-performance potassium-ion storage materials.

关键词： Flexible design Finite element simulation Sulfur-/nitrogen-Co-doped Anode Potassium-ion storage

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Degree sum conditions for hamiltonian index

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Applied Mathematics(A Journal of Chinese Universities) 2021年第3期36卷 403-411页

作者： LIU Ze-meng xiong Li-ming School of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100081China School of Mathematics and Statistics Beijing Key Laboratory on MCAACIBeijing Institute of TechnologyBeijing 100081China

In this note,we show a sharp lower bound of min{Σ_(i=1)^(k)dG(u_(i)):u1u2...uk is a path of(2-)connected G}on its order such that(k-1)-iterated line graphs L^(k-1)(G)are hamiltonian.

关键词： iterated line graph hamiltonian index degree sum condition

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Fluorescent carbon dots synthesized in solid phase and air for application in LEDs

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Nano Research 2024年第9期17卷 8495-8503页

作者： Wei-Jie Zheng Zhao-Nan Sun Yi-ming Wang Huan-ming xiong Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200438China

Carbon dots(CDs)have been widely adopted as optical materials because of their excellent luminescent ***,most of the reported synthetic methods are conducted in solvents,especially hydrothermal/solvothermal reactions,leading to intractable problems such as toxic and flammable solvents,complex and inseparable by-products,and dangerously high pressures and ***-phase synthesis of CDs in air is an effective solution to overcome the above issues,but solid reactions always result in uncontrolled growth and agglomeration of *** this study,some inorganic salts are selected as catalysts for synthesizing CDs in solid states and air,which also play as dispersants to hinder CDs *** the meantime,some aromatic derivatives containing hydroxyl and amino groups are chosen as carbon sources,ground with the optimized catalyst,and then heated together in *** production yields are affected by the reaction time and reactant ratio,while the graphitization degrees of the CDs are determined by the reaction *** IG/ID value of their Raman spectra increases from 0.59 to 0.85,and the particle size decreases from 2.5 to 1.4 nm when the synthesis temperature is increased from 200 to 280℃.The as-prepared CDs show emission peaks ranging from 366 to 606 nm,with the photoluminescence(PL)quantum yield up to 53%.Their emission color variation mainly results from different carbon sources,which can be ascribed to the differences in the element composition,functional groups,and graphitic nitrogen content of these *** dispersing CDs of different concentrations into polyvinyl alcohol(PVA)and combining them with blue LEDs,cold,standard,and warm white light emitting devices(WLEDs)are prepared,with a color rendering index(CRI)up to *** the as-prepared CDs have antioxidant ability at high temperature,the as-prepared WLEDs have long lifespans,remaining the effective white luminescence after 72 h continuous work.

关键词： carbon dot solid-phase synthesis white LED photoluminescence inorganic salt catalysis

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PREDICTION OF PODDED PROPELLER CAVITATION USING AN UNSTEADY SURFACE PANEL METHOD

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Journal of Hydrodynamics 2008年第6期20卷 790-796页

作者： YE Jin-ming xiong Ying College of Naval Architecture and Power Naval University of Engineering Wuhan 430033 China

The unsteady sheet cavitation of podded propeller was predicted by using a surface panel method. The interaction between propeller and pod was treated with the iterative calculation of induced velocity potential, and the method of induced velocity potential can save a great deal of storage and computation time compared to the method of induced velocity. The induced velocity potential of unit singularity on every pod panel to every key blade panel and of unit singularity on every key blade panel and its wake panel to every pod panel were calculated when the key blade is at every angle position. Based on the wake model of the conventional single propeller, a new wake model of podded propeller was constructed. The propeller is analyzed only on the key blade in order to save computation time and memory space. The method can be used to calculate the hydrodynamics performance and cavitation of propeller in uniform and non-uniform inflows. It can give the unsteady force and cavitation shape of propeller. The propeller cavitation range determined by the present method agrees with the observation results of cavity image given in cavitation tunnel well, and this proves the practicability of the method.

关键词： pod propeller unsteady performance cavitation surface panel method

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B(LF,ω～2 )-refinability of inverse limits

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Applied Mathematics(A Journal of Chinese Universities) 2010年第4期25卷 496-502页

作者： xiong Zhao-hui YANG ming-quan Department of Mathematics Zhejiang Sci-Tech University Hangzhou 310018 China Department of Mathematics Jiaxing College Jiaxing 314001 China

Let X be the limit of an inverse system {Xα, παβ, ∧} and and let λ be the cardinal number of A. Assume that each projection πα ： X → Xα is an open and onto map and X is A-paracompact. We prove that if each Xα is B（LF, ω^2）-refinable （hereditarily B（LF, ω^2）- refinable）, then X is B（LF, ω^2）-refinable （hereditarily B（LF,ω ^2）-refinable）. Furthermore, we show that B（LF, ω^2）-refinable spaces can be preserved inversely undcr closed maps.

关键词： Inverse limit B(LF ω^2)-refinability hereditary B(LF,ω ^2)-refinability.

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Solution of Terzaghi one-dimensional consolidation equation with general boundary conditions

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Journal of Central South University 2013年第8期20卷 2239-2244页

作者： MEI Guo-xiong CHEN Qi-ming College of Transportation Engineering Nanjing University of Technology Nanjing 210009 China Louisiana Transportation Research Center Louisiana State University Baton Rouge 70808 USA

Boundary conditions for the classical solution of the Terzaghi one-dimensional consolidation equation conflict with the equation＇s initial condition. As such, the classical initial-boundary value problem for the Terzaghi one-dimensional consolidation equation is not well-posed. Moreover, the classical boundary conditions of the equation can only be applied to problems with either perfectly pervious or perfectly impervious boundaries. General boundary conditions are proposed to overcome these shortcomings and thus transfer the solution of the Terzaghi one-dimensional consolidation equation to a well-posed initial boundary value problem. The solution for proposed general boundary conditions is validated by comparing it to the classical solution. The actual field drainage conditions can be simulated by adjusting the values of parameters b and c given in the proposed general botmdary conditions. For relatively high coefficient of consolidation, just one term in series expansions is enough to obtain results with acceptable accuracy.

关键词： consolidation boundary condition pore water pressure consolidation degree

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