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Numerical studies of the hydrodynamic damping of a vibrating hydrofoil in torsional mode

Journal of Hydrodynamics 2021年第2期33卷 347-360页

作者： Yong-shun Zeng Zhi-feng Yao Biao huang Fu-jun Wang Qin Wu ruo-fu Xiao Guo-yu Wang College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System Beijing 100083China School of Mechanical and Vehicular Engineering Beijing Institute of TechnologyBeijing 100081China

The vortex-induced vibration may lead to a premature failure of hydraulic mechanical systems,especially under the resonance condition in the torsional *** predict the structural fatigue life,a careful consideration of the dynamic response to the hydraulic excitations is essential in the design *** study focuses on the numerical investigation of the relationship between the flow velocity,the added mass and the hydrodynamic damping,particularly,with respect to a Donaldson-type hydrofoil,vibrating in the first torsional mode.A two-way fluid-structure interaction(Fsi)method is used to predict above two *** flow velocity is in the range of 0 m/s-20m/*** evaluate the hydrodynamic damping ratio,an identification method is proposed,based on a modified version of the logarithmic decay *** relative deviations of the simulated natural frequencies and hydrodynamic damping ratios as compared with the experimental data for the first torsional modes,are within 8.1%and 16.6%,*** analysis results show that the added mass coefficient for the first torsional mode is in the range of 1.59-1.86,and is around 44%of that for the first bending *** trends of the boundary layer thickness and the wake width against the reduced velocity are found to be opposite to that of the hydrodynamic damping *** theoretical equation for predicting the hydrodynamic damping ratio is modified,which is shown to be more reliable due to its consideration of the velocity independent hydrodynamic damping phase.

关键词： Torsional mode hydrodynamic damping added mass hydrofoil Donaldson trailing edge

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Semi-synthesis of disulfide-linked branched tri-ubiquitin mimics

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Science China Chemistry 2018年第4期61卷 412-417页

作者： Yanyan si Lujun Liang Shan Tang Yunkun Qi Yong huang Lei Liu Key Laboratory of Chemical Genomics School of Chemical Biology and BiotechnologyPeking UniversityShenzhen Graduate School Department of Chemistry Tsinghua University

Ubiquitin(Ub) chain isopeptide bond mimics are useful molecules for biochemical and biophysical studies. Herein, we report the semi-synthesis of the disulfide-linked K11/K48-branched tri-Ub(Ub_3^(11/48)(S-S)), the first example of an isopeptide mimic for the branched Ub chains,which have recently emerged as an interesting category of Ub modifications. Our strategy comprised the El-dependent synthesis of the Ub conjugate of aminoethanethiol, followed by disulfide formation with Ub(K11 C, K48 C). The structure of the synthetic isopeptide bond mimics was verified by the crystal structure of Ub_3^(11/48)(S-S). Deubiquitination and pulldown assays indicated that the synthetic Ub_3^(11/48)(S-S) could be hydrolyzed by linkage-specific deubiquitinases(K11-specific Cezanne and K48-specific OTUB1), and recognized by proteasomal ubiquitin receptor S5 a.

关键词： ubiquitin chain isopeptide bond mimics disulfide-directed strategy branched Ub chains crystal structure

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High production of fatty alcohols in Yarrowia lipolytica by coordination with glycolysis

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Science China Chemistry 2019年第8期62卷 1007-1016页

作者： Jin-Lai Zhang Ying-Xiu Cao Yang-Zi Peng Cong-Cong Jin Qiu-Yan Bai ruo-si Zhang Duo Liu Ying-Jin Yuan Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education) Tianjin University Tianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China

Fatty alcohol biosynthesis by oleaginous microbes was a promising alternative to the petroleum or other non-renewable resources-based process. However, low titer and yield hamper the further industrial and commercial applications. Here, we developed an efficient strategy to coordinate fatty alcohol with glycolysis which achieved a ‘pull-and-push’ effect to improve fatty alcohol production. Transcript profiling indicated that genes in carbohydrate metabolism were up-regulated significantly in response to high fatty alcohol production. Based on it, 11 glycolysis promoters were screening to express fatty acyl-CoA reductase(FAR) to relate the fatty alcohol production with the up-regulated carbohydrate metabolism, and the fatty alcohol production reached 557 mg/L when FAR was expressed by the promoter of PFBAin. RNA-seq and qRT-PCR analysis demonstrated that a ‘pull-and-push’ effect caused by the coordination system dynamically enhanced the product synthesis flux from top to bottom, which was also testified and intensified by doubled glucose concentration. After manipulating structural and regulatory genes of lipid metabolism, the final strain achieved up to 5.75 g/L fatty alcohol production from modified YPD medium(containing 91 g/L glucose) in shake flasks, which represented the highest titer reported to date. This work offered a feasible and effective reference for dynamic manipulation of fatty acid-derived chemicals synthesis.

关键词： fatty alcohol biosynthesis coordinative expression Yarrowia lipolytica fatty acyl-CoA reductase(FAR) metabolic engineering

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Physical properties and device applications of graphene oxide

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Frontiers of physics 2020年第3期15卷 27-96页

作者： Xiao-Ming huang Li-Zhao Liu si Zhou Ji-Jun Zhao School of Ocean Science and Technology Dalian University of TechnologyPanjin124221China School of Mathematical and Physical Sciences Dalian University of TechnologyPanjin124221China Key Laboratory of Materials Modification by Laser Ion and Electron BeamsDalian University of TechnologyMinistry of EducationDalian116024China

Graphene oxide(GO),the functionalized graphene with oxygenated groups(mainly epoxy and hydroxyl),has attracted resurgent interests in the past decade owing to its large surface area,superior physical and chemical properties,and easy composition with other materials via surface functional ***,GO is used as an important raw material for mass production of graphene via ***,under different conditions,the coverage,types,and arrangements of oxygen-containing groups in GO can be varied,which give rise to excellent and controllable physical properties,such as tunable electronic and mechanical properties depending closely on oxidation degree,suppressed thermal conductivity,optical transparency and fluorescence,and nonlinear optical *** on these outstanding properties,many electronic,optical,optoelectronic,and thermoelectric devices with high performance can be achieved on the basis of *** we present a comprehensive review on recent progress of GO,focusing on the atomic structures,fundamental physical properties,and related device applications,including transparent and flexible conductors,field-effect transistors,electrical and optical sensors,fluorescence quenchers,optical limiters and absorbers,surface enhanced Raman scattering detectors,solar cells,light-emitting diodes,and thermal rectifiers.

关键词： graphene oxide mechanics electronics thermal properties nonlinear optics

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Highly elastic and degradable vitrimeric elastomers using polycondensation

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Chinese Chemical Letters 2024年第3期35卷 434-438页

作者： Yue Liu Yongshuang huang Chao Li Guifu si Min Chen Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei 230601China CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Introducing covalently crosslinked network to polymer matrix can merge the advantages in reprocessing and durability of *** this contribution,a series of high-performance vitrimeric elastomers were achieved via *** topological structures of polymers were tuned by varying the feeding ratios of bisacetoacetate,hex–substituted bisacetoacetate,bisamine and tris(2-aminoethyl)*** these structural manipulations,the vitrimeric elastomers presented great elastic recovery properties(strain recovery value up to 80%)benefiting from the introduction of long chain ***,the elastomers exhibited excellent reprocessing property,water vapor/oxygen barrier and adhesive ***,the elastomers could be degraded into monomer under acid conditions which enabled the elastomer synthesis again in closed loop recycling *** ease of the polycondensation in this work to prepare highly elastic and recyclable vitrimeric elastomers demonstrated exciting opportunities for the synthesis of sustainable polymers.

关键词： Polycondensation Vitrimeric elastomers Highly elastic Degradable polymers

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流媒体视听产品传播逻辑、观看模式与生产机制研究

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当代电影 2020年第10期 158-164页

作者：司若黄莺清华大学新闻与传播学院

流媒体平台改变了线性传播逻辑,突破了传统电影传播的容量约束和特定时间限制,转而成为一种非线性传播方式。传播方式的改变促使观看模式和电影内容制作进入新阶段。流媒体平台给予用户更大的主动权,逐渐从单纯的观看行为向更多元化的... 详细信息

流媒体平台改变了线性传播逻辑,突破了传统电影传播的容量约束和特定时间限制,转而成为一种非线性传播方式。传播方式的改变促使观看模式和电影内容制作进入新阶段。流媒体平台给予用户更大的主动权,逐渐从单纯的观看行为向更多元化的使用行为过渡。创作法则趋向于符合数据库逻辑,将文化内容分解为可被数据化、更小单位的"文化模因"进行重新组合。综上所述,本文认为纯网播电影与院线电影在质量和影响力上的差异将越来越小,流媒体平台颠覆电影传播和体验方式,也因此延续了电影的生命力。

关键词：流媒体传播逻辑生产机制非线性传播文化模因

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多元体验建构:疫情下2020年中国电影产业发展趋势预判

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北京电影学院学报 2020年第4期 4-12页

作者：司若黄莺北京电影学院未来影像高精尖创新中心清华大学新闻与传播学院澳门科技大学人文艺术学院

因新冠肺炎疫情的巨大冲击,中国电影产业多年来稳步发展的势头在2020年被按下了暂停键。危机正是反思的时机,作为解决当前问题的重要参考项,本文回溯了SARS疫情对中国电影产业的冲击和后续影响。综合历史经验和当下情境,分析新冠肺炎疫... 详细信息

因新冠肺炎疫情的巨大冲击,中国电影产业多年来稳步发展的势头在2020年被按下了暂停键。危机正是反思的时机,作为解决当前问题的重要参考项,本文回溯了SARS疫情对中国电影产业的冲击和后续影响。综合历史经验和当下情境,分析新冠肺炎疫情和当前电影产业本身发展状态所带来的具体问题,由此提出对疫情后电影产业重点发展方向的预判。

关键词：新冠肺炎疫情中国电影产业保障机制版权价值开发

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Landslide susceptibility mapping of mountain roads based on machine learning combined model

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Journal of Mountain Science 2023年第5期20卷 1232-1248页

作者： DOU Hong-qiang huang si-yi JIAN Wen-bin WANG Hao Zijin School of Geology and Mining Fuzhou UniversityFuzhou 350116China Fujian Key Laboratory of Geohazard Prevention Fuzhou 350002China

Landslide susceptibility mapping of mountain roads is frequently confronted by insufficient historical landslide sample data,multicollinearity of existing evaluation index factors,and inconsistency of evaluation factors due to regional environmental ***,a single machine learning model can easily become overfitting,thus reducing the accuracy and robustness of the evaluation *** paper proposes a combined machine-learning model to address the *** landslide susceptibility in mountain roads were mapped by using factor analysis to normalize and reduce the dimensionality of the initial condition factor and generating six new combination factors as evaluation *** mountain roads in the Youxi County,Fujian Province,China were used for the landslide susceptibility *** most frequently used machine learning techniques,support vector machine(SVM),random forest(RF),and artificial neural network(ANN)models,were used to model the landslide susceptibility of the study area and validate the accuracy of this evaluation index *** global minimum variance portfolio was utilized to construct a machine learning combined model.5-fold cross-validation,statistical indexes,and AUC(Area Under Curve)values were implemented to evaluate the predictive accuracy of the landslide susceptibility *** mean AUC values for the SVM,RF,and ANN models in the training stage were 89.2%,88.5%,and 87.9%,respectively,and 78.0%,73.7%,and 76.7%,respectively,in the validating *** the training and validation stages,the mean AUC values of the combined model were 92.4% and 87.1%,*** combined model provides greater prediction accuracy and model robustness than one single model.

关键词： Landslide susceptibility mapping Factor analysis Machinelearning Combinedmodel Mountain roads

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中国网络电影发展脉络与未来趋势研究

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电影艺术 2020年第4期 22-30页

作者：司若黄莺清华大学新闻与传播学院北京电影学院未来影像高精尖创新中心澳门科技大学人文艺术学院

视频网站在2000年后兴起并逐渐从播放其他影视公司版权内容的平台向制作原创内容的平台过渡。网络电影在这一趋势下诞生,并因为新冠肺炎疫情加快了整体的转型升级速度。本文梳理中国网络电影发展脉络,分析"头部""腰部"和"尾部"网络电影... 详细信息

视频网站在2000年后兴起并逐渐从播放其他影视公司版权内容的平台向制作原创内容的平台过渡。网络电影在这一趋势下诞生,并因为新冠肺炎疫情加快了整体的转型升级速度。本文梳理中国网络电影发展脉络,分析"头部""腰部"和"尾部"网络电影发展现状和趋势,以及其对互联网泛娱乐视听体系的巨大引流和增值潜力。运用长尾效应、注意力经济以及相关媒介理论来解释网络电影对电影产业化、电影格式创新、院线电影类型、影院空间新生产等电影生态的影响力。

关键词：网络电影视频平台泛娱乐视听体系电影产业生态

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Effects of artificially induced complete mixing on dissolved organic matter in a stratified source water reservoir

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Journal of Environmental Sciences 2022年第1期34卷 130-140页

作者： Lingyun Zhao Nan Li Tinglin huang Haihan Zhang Fan si Kai Li Yunzhi Qi Fengyao Hua Cheng huang Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi'an University of Architecture and TechnologyXi'an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Xi'an Water Group HeiheJinpen Reservoir Management Company Xi'an 710016China

Naturally complete mixing promotes the spontaneous redistribution of dissolved oxygen(DO),representing an ideal state for maintaining good water quality,and conducive to the biomineralization of organic *** lifting aerators(WLAs)can extend the periods of complete mixing and increase the initial mixing *** evaluate the influence of artificial-induced continuously mixing on dissolved organic matter(DOM)removal performance,the variations of DOM concentrations,optical characteristic,environmental factors were studied after approaching the total mixing status via WLAs *** this process,the dissolved organic carbon reduced by 39.18%,whereas the permanganate index decreased by 20.47%.The optical properties indicate that the DOM became more endogenous and its molecular weight *** on the results of the Biolog Eco Plates,the microorganisms were maintained at a relatively high metabolic activity in the early stage of induced mixing when the mixing temperature was relatively high,whereas DOM declined at a high *** the continuous decrease in the water temperature,both the metabolic capacity and the diversity of aerobic microorganisms significantly decreased,and the rate of organic matter mineralization slowed *** results of this study demonstrate that the artificial induced mixing largely enhanced the removal DOM performance by providing a long period of aerobic conditions and higher initial temperature.

关键词： Artificial destratification systems Organic matter Lake and reservoir management EEMs-PARAFAC

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