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Establishment risk of invasive golden mussel in a water diversion project:An assessment framework

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Environmental Science and Ecotechnology 2024年第1期17卷 138-154页

作者： Yao Yang Mengzhen Xu Xingyu Chen Jiahao Zhang ShuleiWang Jianying Zhu xudong fu State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China China South-to-north Water Diversion Corporation Limited China Department of Mathematical Sciences Tsinghua UniversityBeijing100084China

Inter-basin water diversion projects have led to accelerated colonization of aquatic organisms,including the freshwater golden mussel(Limnoperna fortunei),exacerbating global biofouling *** the influence of environmental factors on the mussel's invasion and biofouling impact has been studied,quantitative correlations and underlying mechanisms remain unclear,particularly in large-scale interbasin water diversion projects with diverse hydrodynamic and environmental ***,we examine the comprehensive impact of environmental variables on the establishment risk of the golden mussel in China's 1432-km-long Middle Route of the South-to-North Water Diversion *** regression and multiclass classification models were used to investigate the environmental influence on the occurrence probability and reproductive density of the golden *** nitrogen,ammonia nitrogen,water temperature,pH,and velocity were identified as crucial environmental variables affecting the biofouling risk in the *** regression analysis revealed a negative correlation between the occurrence probability of all larval stages and levels of total nitrogen and ammonia *** multiclass classification model showed that elevated levels of total nitrogen hindered mussel reproduction,while optimal water temperature enhanced their reproductive *** velocity and pH levels were crucial in maintaining moderate larval *** research presents a quantitative analytical framework for assessing establishment risks associated with invasive mussels,and the framework is expected to enhance invasion management and mitigate biofouling issues in water diversion projects worldwide.

关键词： Golden mussel Environmental variables Multiclass classification Logistic regression Quantitative risk assessment

数字流域模型淤地坝模块改进及减水减沙效益评估

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应用基础与工程科学学报 2024年第2期32卷 301-313页

作者：张玍傅旭东孙凯王晨沣清华大学水沙科学与水利水电工程国家重点实验室北京100084

淤地坝具有重要的水土保持作用,但其减水减沙效益的科学评估仍存在困难.一方面,淤地坝减水减沙的物理机制仍难以刻画;另一方面,观测资料有限且难以获取.以概化淤地坝卧管及溢洪道等部分的泄流机制及整体水沙调控机制为基础,改进和检验... 详细信息

淤地坝具有重要的水土保持作用,但其减水减沙效益的科学评估仍存在困难.一方面,淤地坝减水减沙的物理机制仍难以刻画;另一方面,观测资料有限且难以获取.以概化淤地坝卧管及溢洪道等部分的泄流机制及整体水沙调控机制为基础,改进和检验了数字流域模型的淤地坝模块,应用改进后的模型模拟皇甫川流域水沙过程并评估淤地坝减水减沙效益.研究结果表明:不考虑淤地坝的情况下,模型对淤地坝数量较少的近似自然状态期(1979~1986年)适用性较好,而对淤地坝数量较多的受扰状态期(2007~2012年)适用性较差,水沙模拟值明显高于实测值.考虑淤地坝的物理机制后,与原模型相比,除个别年份外,改进后的模型对受扰状态期水沙过程的模拟精度具有明显的提高,其逐日流量NSE(Nash-Sutcliffe效率系数)从-51.085~0.450提高到0.134~0.802,逐日输沙率NSE从-56.740~0.390提高到0.066~0.857.使用改进后的模型计算得受扰状态期淤地坝平均拦水量为0.142×10^(8)m^(3),减水效益为40.9%;平均拦沙量为0.050×10^(8)t,减沙效益为50.3%.研究成果可为认识淤地坝调控水沙物理机制提供模型支撑和为淤地坝建设规划提供科学指导.

关键词：淤地坝减水减沙减水减沙效益水土保持数字流域模型分布式水沙模型皇甫川

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埋入式后压浆管桩竖向抗拔破坏模式研究

铁道科学与工程学报 2024年第2期21卷 602-612页

作者：邹志炎卢继忠张逸博傅旭东武汉大学土木建筑工程学院湖北武汉430072

埋入式后压浆管桩作为一种新型桩基础,集钻孔灌注桩和预应力管桩的优点于一体,可以解决灌注桩桩身质量不可靠和预应力管桩沉桩困难等问题。对埋入式后压浆管桩的竖向抗拔试验进行CT扫描,得到不同位移状态下模型桩的CT扫描图像,直观地揭... 详细信息

埋入式后压浆管桩作为一种新型桩基础,集钻孔灌注桩和预应力管桩的优点于一体,可以解决灌注桩桩身质量不可靠和预应力管桩沉桩困难等问题。对埋入式后压浆管桩的竖向抗拔试验进行CT扫描,得到不同位移状态下模型桩的CT扫描图像,直观地揭示破坏面的发展规律,并建立破坏面方程。对其他学者提出的抗拔桩破坏面方程进行优化,通过静力平衡方程,获得优化后破坏面方程对应的埋入式后压浆管桩抗拔极限承载力函数,并采用遗传算法确定优化后破坏面方程的参数。将多种理论假定破坏面与试验获得的破坏面进行对比分析,验证所得破坏面方程的准确性。研究发现:埋入式后压浆管桩在上拔位移到达0.45倍桩径时发生破坏,此时灌浆层与土体紧密结合,两者之间未出现明显位移,破坏仅发生在灌浆层之外的桩周土体中;破坏面从桩底向桩顶延伸,越靠近桩顶,破坏面距离桩身越远,破坏面在桩底与混凝土侧壁相切,在地面与水平面的夹角接近42°,呈喇叭形破坏;本文的理论假定破坏面与试验获得的破坏面的相关指数R^(2)=0.97,前人的理论假定破坏面与试验获得的破坏面的相关指数R^(2)=0.91,本文的破坏面方程更加贴近试验获得的破坏面。研究成果对埋入式后压浆管桩的设计计算具有重要的参考价值。

关键词：铁路电力工程埋入式后压浆管桩 CT扫描破坏面抗拔极限承载力遗传算法

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融媒体中心演播室灯光技术探究

电视技术 2024年第3期48卷 1-4页

作者：傅煦栋莱州市融媒体中心山东莱州261400

随着媒体融合的不断深入发展,融媒体中心演播室灯光技术在提升节目质量、满足观众需求方面具有重要意义。针对融媒体中心演播室灯光技术进行深入研究,探讨其发展趋势、技术要点和创新应用。首先,详细分析演播室灯光技术在塑造场景氛围... 详细信息

随着媒体融合的不断深入发展,融媒体中心演播室灯光技术在提升节目质量、满足观众需求方面具有重要意义。针对融媒体中心演播室灯光技术进行深入研究,探讨其发展趋势、技术要点和创新应用。首先,详细分析演播室灯光技术在塑造场景氛围、突出节目主题、展现人物形象等方面的作用。其次,探讨新媒体时代演播室灯光技术面临的需求和挑战。最后,关注节能环保这一演播室灯光技术发展的重要方向,为我国媒体融合发展提供有益参考。

关键词：融媒体中心演播室灯光灯光技术

Theory of delayed response in river morphodynamics:Applicability and limitations

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International Journal of Sediment Research 2022年第2期37卷 162-172页

作者： Chenge An xudong fu State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University

The delayed response of fluvial rivers to external disturbances has been described by many *** simulate such behavior,the rate law model(or the delayed response model) was developed by previous researchers,and has been applied to a series of river morphological ***,to date,the applicability of the rate law model has not been fully *** the current paper,a physicallybased analysis of the rate law model is presented to assess the responses of bed elevation and the grain size of surface sediment,using the response of the Shi-ting River,China,after the 2008 Wenchuan Earthquake as an ***,a physically-based river morphodynamic model is implemented to reproduce the post-earthquake adjustments of the Shi-ting ***,the mathematical properties of the Hirano-Exner equation,which describes the dynamics of both bed elevation and surface texture,are *** is shown that the dynamics of bed elevation are dominated by a diffusion process and the analytical solution for bed elevation has a similar mathematical formulation to that of the rate law ***,the rate law and morphodynamic models similarly predict the adjustment of bed *** contrast,the dynamics of bed surface texture are controlled by both advection and diffusion *** advection and diffusion processes dominate adjustments over the short(annual to decadal scale) and long(century to millenial scale) terms,*** physics produce the multi-scale and nonmonotonic character of the adjustment of bed surface *** a result,the rate law model is incapable of describing the adjustment of bed surface *** findings highlight the applicability and limitations of the rate law model in simulating river morphodynamic processes.

关键词： Rate law River morphodynamics Hirano–Exner equation Advection Diffusion Multi-scale processes

Stochastic formulation of particle kinetics in wall-bounded two-phase flows

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Science China(Technological Sciences) 2014年第10期57卷 2001-2011页

作者： MA HongBo fu xudong State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University

This paper presents a generalized framework of stochastic modeling for particle kinetics in wall-bounded *** modified a reflected Brownian motion process and straightforwardly obtained a Kramers equation for particle probability density function(PDF).After the wall effects were accounted for as a drift from zero in the mean displacement and suppression in the diffusivity of a particle,an analytical solution was worked out for *** distinguishable mechanisms were identified to affect the profile of particle probability distribution:external forces,turbophoresis effect,and wall-drift *** proposed formulation covers the Huang et al.(2009)model of a wall that produces electrostatic repulsion force and van der Waals force,as well as Monte-Carlo solutions for the Peter and Barenbrug(2002)model under a variety of relaxation ***,it successfully reproduces the two patterns of particle concentration profiles observed in experiments of sediment-laden open-channel *** strength of the wall-drift effect was found to be connected with the interaction frequency between particle and *** exploration of the relationship among flow turbulence,particle inertia,and particle concentration is worthwhile.

关键词： stochastic formulation Kramers equation reflected Brownian motion wall-bounded flow two-phase flow concentration profile

超临界CO_(2)辅助热塑性聚氨酯/热塑性聚酯弹性体的发泡及其回弹特性

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高分子材料科学与工程 2024年第2期40卷 74-82页

作者：周梓傲唐文卓刘清亭张荣付旭东胡圣飞湖北工业大学绿色轻工材料湖北省重点实验室新材料与绿色制造人才引进创新示范基地湖北武汉430068

为克服热塑性聚氨酯(TPU)发泡后,其发泡材料回弹性不足、压缩强度低及收缩率大等问题,采用热塑性聚酯弹性体(TPEE)改性TPU,并以超临界CO_(2)为发泡剂,制备了TPU/TPEE发泡材料。研究了TPU/TPEE共混物的熔融及结晶行为、流变性能以及TPEE... 详细信息

为克服热塑性聚氨酯(TPU)发泡后,其发泡材料回弹性不足、压缩强度低及收缩率大等问题,采用热塑性聚酯弹性体(TPEE)改性TPU,并以超临界CO_(2)为发泡剂,制备了TPU/TPEE发泡材料。研究了TPU/TPEE共混物的熔融及结晶行为、流变性能以及TPEE含量对TPU/TPEE发泡材料循环压缩性能、回弹性能、压缩永久变形及发泡性能的影响。差示扫描量热仪与落球回弹、压缩永久形变结果表明,TPEE的加入能使TPU分子链排列的有序性降低,回弹性提高;旋转流变仪结果表明,TPEE的引入可以有效改善共混物熔体的黏弹性,使得弹性作为主导,并显著改善发泡性能;循环压缩结果表明,加入TPEE可以进一步改善泡沫的压缩性能。当添加TPEE的质量分数为7%时,TPU/TPEE发泡体相对于纯TPU泡沫,发泡体落球回弹性提高了7.25%、压缩永久变形值降低了2.84%、压缩强度提高了326%。

关键词：热塑性聚氨酯热塑性聚酯弹性体超临界CO_(2) 发泡材料

A surface-based hiding function linking flume and field data

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Science China(Technological Sciences) 2017年第10期60卷 1560-1569页

作者： ZHANG LiGuo fu xudong DUAN Jennifer G State Key Laboratory of Hydroscience and Engineering Tsinghua University Department of Civil Engineering and Engineering Mechanics University of Arizona

The quantification of the sheltering and exposure effects of non-uniform sediments has been widely achieved through hiding function models. Big challenge exists so far in the model parameter that is highly variable and differs greatly between laboratory flumes and field streams. This paper presents an improved surface-based hiding fimction. The force balance for particle inception was formulated and the allocation of the overall bed shear stress into each group of sediments was mimicked. The new hiding function was examined against and agrees well with the documented field and flume data. It was shown that the hiding fimction is closely related to the relative flow depth and the reference elevation in the velocity profile in addition to the bed material gradation. The power law of velocity profile that applies to both flume flows and natural streams can link the flume and field data together. The hiding function with b = 1/6 and b = 1/2 is applicable to natural streams and laboratory flumes, respectively. The value orb = 0.263 also works well for gravel bed rivers. The range of the reference elevation, namely z0 = 0.4Dm-1.4Dm, is recommended for either the flume or field data. The new hiding function contributes to addressing clearer physical meanings and a useful perspective for further improvement.

关键词： hiding function relative flow depth flume and field data reference elevation

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天然粘土矿物材料在质子交换膜中的应用进展

复合材料学报 2024年第3期41卷 1166-1178页

作者：王贝凌志伟周依琳付旭东张荣胡圣飞李骁刘清亭湖北工业大学绿色轻工材料湖北省重点实验室武汉430068 湖北工业大学材料与化学工程学院武汉430068 武汉众宇动力系统科技有限公司武汉430079

质子交换膜(PEM)作为聚合物电解质燃料电池关键部件直接影响着电池性能,拓宽其运行温度和湿度范围有利于简化燃料电池水、热管理设计,从而促进电池小型化和降低成本。近些年来,开发天然粘土/聚合物复合膜已成为提升传统PEM性能和拓宽其... 详细信息

质子交换膜(PEM)作为聚合物电解质燃料电池关键部件直接影响着电池性能,拓宽其运行温度和湿度范围有利于简化燃料电池水、热管理设计,从而促进电池小型化和降低成本。近些年来,开发天然粘土/聚合物复合膜已成为提升传统PEM性能和拓宽其应用温、湿度范围的重要途径之一。天然粘土矿物多为含水层状硅酸盐化合物,特殊的孔、层结构和纳米尺度赋予其较大的比表面积和表面效应,其表面和层间富含的羟基在提高复合膜机械强度的同时固定了传质介质,从而在复合膜中构建新的质子传导通道用以提高膜的性能。从纳米微观多个维度综述了不同类别粘土矿物的结构与性能,以及其在质子交换膜中的研究进展,对天然粘土矿物复合质子交换膜的研究进行了总结与展望。

关键词：天然粘土矿物质子交换膜复合膜纳米尺度燃料电池