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Numerical investigation of hydro-morphodynamic characteristics of a cascading failure of landslide dams

Journal of Mountain Science 2024年第6期21卷 1868-1885页

作者： ZHONG qiming CHEN Lingchun MEI Shengyao SHAN Yibo WU Hao zhao Kunpeng Department of Geotechnical Engineering Nanjing Hydraulic Research InstituteNanjing 210024China National Key Laboratory of Water Disaster Prevention Nanjing 210098China Key Laboratory of Reservoir and Dam Safety of the Ministry of Water Resources Nanjing 210029China

A cascading failure of landslide dams caused by strong earthquakes or torrential rains in mountainous river valleys can pose great threats to people’s lives,properties,and infrastructures.In this study,based on the three-dimensional Reynoldsaveraged Navier-Stokes equations(RANS),the renormalization group(RNG)k-εturbulence model,suspended and bed load transport equations,and the instability discriminant formula of dam breach side slope,and the explicit finite volume method(FVM),a detailed numerical simulation model for calculating the hydro-morphodynamic characteristics of cascading dam breach process has been developed.The developed numerical model can simulate the breach hydrograph and the dam breach morphology evolution during the cascading failure process of landslide dams.A model test of the breaches of two cascading landslide dams has been used as the validation case.The comparison of the calculated and measured results indicates that the breach hydrograph and the breach morphology evolution process of the upstream and downstream dams are generally consistent with each other,and the relative errors of the key breaching parameters,i.e.,the peak breach flow and the time to peak of each dam,are less than±5%.Further,the comparison of the breach hydrographs of the upstream and downstream dams shows that there is an amplification effect of the breach flood on the cascading landslide dam failures.Three key parameters,i.e.,the distance between the upstream and the downstream dams,the river channel slope,and the downstream dam height,have been used to study the flood amplification effect.The parameter sensitivity analyses show that the peak breach flow at the downstream dam decreases with increasing distance between the upstream and the downstream dams,and the downstream dam height.Further,the peak breach flow at the downstream dam first increases and then decreases with steepening of the river channel slope.When the flood caused by the upstream dam failure flows to the downstream dam,it can produce a surge wave that

关键词： Cascading landslide dams Cascading dam failure process Detailed numerical simulation model Flood amplification effect Parameter sensitivity analyses

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Data-driven intelligent modeling framework for the steam cracking process

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Chinese Journal of Chemical Engineering 2023年第9期61卷 237-247页

作者： qiming zhao Kexin Bi Tong Qiu Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Beijing Key Laboratory of Industrial Big Data Systems and Applications Tsinghua UniversityBeijing 100084China School of Chemical Engineering Sichuan UniversitySichuan 610065China Department of Bioprocess Engineering Institute of BiotechnologyTechnische Universität BerlinBerlin 10623Germany

Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical industry.Predictive models of the cracking process can boost production efficiency and profit margin.Rapid advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process modeling.Meanwhile,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational speed.This research presents a framework for data-driven intelligent modeling of the steam cracking process.Industrial data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means clustering.We propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying instances.The framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.

关键词： Mathematical modeling Data-driven modeling Process systems Steam cracking Clustering Multivariate adaptive regression spline

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Predicting power conversion efficiency of binary organic solar cells based on Y6 acceptor by machine learning

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Journal of Energy Chemistry 2023年第7期82卷 139-147,I0004页

作者： qiming zhao Yuqing Shan Chongchen Xiang Jinglun Wang Yingping Zou Guangjun Zhang Wanqiang Liu School of Chemistry and Chemical Engineering Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of EducationHunan University of Science and TechnologyXiangtan 411100HunanChina College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083HunanChina

Organic solar cells(OSCs)are a promising photovoltaic technology for practical applications.However,the design and synthesis of donor materials molecules based on traditional experimental trial-anderror methods are often complex and expensive in terms of money and time.Machine learning(ML)can effectively learn from data sets and build reliable models to predict the performance of materials with reasonable accuracy.Y6 has become the landmark high-performance OSC acceptor material.We collected the power conversion efficiency(PCE)of small molecular donors and polymer donors based on the Y6 acceptor and calculated their molecule structure descriptors.Then we used six types of algorithms to develop models and compare the predictive performance with the coefficient of determination(R^(2))and Pearson correlation coefficient(r)as the metrics.Among them,decision tree-based algorithms showed excellent predictive capability,especially the Gradient Boosting Regression Tree(GBRT)models based on small molecular donors and polymer donors exhibited that the values of R2are 0.84 and 0.69 for the testing set,respectively.Our work provides a strategy to predict PCEs rapidly,and discovers the influence of the descriptors,thereby being expected to screen high-performance donor material molecules.

关键词： Machine learning Binary organic solar cells Y6 PCE

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Nystose attenuates bone loss and promotes BMSCs differentiation to osteoblasts through BMP and Wnt/β-catenin pathway in ovariectomized mice

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Food Science and Human Wellness 2023年第2期12卷 634-646页

作者： Qi Zhang Sijing Hu Jianjun Wu Peng Sun Quanlong Zhang Yang Wang qiming zhao Ting Han Luping Qin Qiaoyan Zhang School of Pharmaceutical Sciences Zhejiang Chinese Medical UniversityHangzhou 310053China Zhejiang Traditional Chinese Medicine&Health Industry Group Co. Ltd.Hangzhou 310016China School of Pharmacy Second Military Medical UniversityShanghai 200433China

Increasing the osteogenic differentiation ability and decreasing the adipogenic differentiation ability of bone marrow mesenchymal stem cells(BMSCs)is a potential strategy for the treatment of osteoporosis(OP).Naturally derived oligosaccharides have shown significant anti-osteoporotic effects.Nystose(NST),an oligosaccharide,was isolated from the roots of Morinda officinalis How.(MO).The aim of the present study was to investigate the effects of NST on bone loss in ovariectomized mice,and explore the underlying mechanism of NST in promoting differentiation of BMSCs to osteoblasts.Administration of NST(40,80 and 160 mg/kg)and the positive control of estradiol valerate(0.2 mg/kg)for 8 weeks significantly prevented bone loss induced by ovariectomy(OVX),increased the bone mass density(BMD),improved the bone microarchitecture and reduced urine calcium and deoxypyridinoline(DPD)in ovariectomized mice,while inhibited the increase of body weight without significantly affecting the uterus weight.Furthermore,we found that NST increased osteogenic differentiation,inhibited adipogenic differentiation of BMSCs in vitro,and upregulated the expression of the key proteins of BMP and Wnt/β-catenin pathways.In addition,Noggin and Dickkopf-related protein-1(DKK-1)reversed the effect of NST on osteogenic differentiation and expression of the key proteins in BMP and Wnt/β-catenin pathway.The luciferase activities and the molecular docking analysis further supported the mechanism of NST.In conclusion,these results indicating that NST can be clinically used as a potential alternative medicine for the prevention and treatment of postmenopausal osteoporosis.

关键词： Nystose Bone marrow mesenchymal stem cell Osteoblast Adipocyte BMP pathway Wnt/β-catenin pathway

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三相电力弹簧的无源控制策略研究

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电机与控制学报 2024年第3期28卷 110-122页

作者：赵永熹张家领程启明上海电力大学自动化工程学院上海200090

针对太阳能、风能等新能源设备大规模并入电网造成的电能质量下降问题,近年来出现了电力弹簧(ES)的概念。依据推导出的三相电力弹簧(TPES)的数学模型,搭建了对应的系统模型,依据无源控制(PBC)理论,分析了系统的无源性,并分别采用传统PI... 详细信息

针对太阳能、风能等新能源设备大规模并入电网造成的电能质量下降问题,近年来出现了电力弹簧(ES)的概念。依据推导出的三相电力弹簧(TPES)的数学模型,搭建了对应的系统模型,依据无源控制(PBC)理论,分析了系统的无源性,并分别采用传统PI控制和无源控制验证了三相电力弹簧能够维持关键负载(CL)电压的稳定。通过仿真和实验验证,在有功功率变动工况下,无源控制的超调量远远低于PI控制的13.7%,调节时间0.03 s也低于PI控制的0.07 s,静差率0.0002%也小于PI控制的0.08%,表明无源控制的动态性能和静态性能都更出色。此外,相比于传统的PI控制,无源控制所需参数更少,控制系统结构更加简单。

关键词：新能源电力弹簧三相电力弹簧关键负载无源控制电能质量电压稳定

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Saturable absorption and visible pulse modulation of few-layer topological nodal-line semimetal HfGeTe

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Chinese Optics Letters 2024年第3期22卷 89-94页

作者：赵启明张首焱王树贤王刚于浩海张怀金 State Key Laboratory of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan 250100China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Topological nodal-line semimetals attract growing research attention in the photonic and optoelectronic fields due to their unique topological energy-level bands and fascinating nonlinear optical responses.Here,to the best of our knowledge,we first report the saturable absorption property of topological nodal-line semimetal HfGeTe and the related pulse modulation in passively Q-switched visible lasers.Few-layer HfGeTe demonstrates outstanding saturable absorption properties in the visible-light band,yielding the saturation intensities of 7.88,12.66,and 6.64μJ/cm^(2)at 515,640,and 720 nm,respectively.Based on an as-prepared few-layer HfGeTe optical switch and a Pr:LiYF_(4)gain medium,Q-switched visible lasers are also successfully achieved at 522,640,and 720 nm.The minimum pulse widths of the green,red,and deep-red pulsed lasers are150,125.5,and 420 ns,respectively.Especially for the green and red pulsed laser,the obtained pulse width is smaller than those of the low-dimensional layered materials.Our work sheds light on the application potential of topological nodal-line semimetals in the generation of visible pulsed lasers.

关键词： visible pulsed laser topological nodal-line semimetals saturable absorption Q-switching Pr doping

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Near Optimal Output Feedback Control of Nonlinear Discrete-time Systems Based on Reinforcement Neural Network Learning

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IEEE/CAA Journal of Automatica Sinica 2014年第4期1卷 372-384页

作者： qiming zhao Hao Xu Sarangapani Jagannathan the DENSO International America Inc. with the College of Science and Engineering Texas A&M University the Department of Electrical&Computer Engineering Missouri University of Science and Technology

In this paper, the output feedback based finitehorizon near optimal regulation of nonlinear affine discretetime systems with unknown system dynamics is considered by using neural networks(NNs) to approximate Hamilton-JacobiBellman(HJB) equation solution. First, a NN-based Luenberger observer is proposed to reconstruct both the system states and the control coefficient matrix. Next, reinforcement learning methodology with actor-critic structure is utilized to approximate the time-varying solution, referred to as the value function, of the HJB equation by using a NN. To properly satisfy the terminal constraint, a new error term is defined and incorporated in the NN update law so that the terminal constraint error is also minimized over time. The NN with constant weights and timedependent activation function is employed to approximate the time-varying value function which is subsequently utilized to generate the finite-horizon near optimal control policy due to NN reconstruction errors. The proposed scheme functions in a forward-in-time manner without offline training phase. Lyapunov analysis is used to investigate the stability of the overall closedloop system. Simulation results are given to show the effectiveness and feasibility of the proposed method.

关键词： Artificial neural networks Observers Optimal control Learning (artificial intelligence) Approximation methods Feedback Nonlinear dynamical systems

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Optimal regulation of uncertain dynamic systems using adaptive dynamic programming

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Journal of Control and Decision 2014年第3期1卷 226-256页

作者： Hao Xu qiming zhao S.Jagannathan Department of Electrical and Computer Engineering Missouri University of Science and TechnologyRollaMOUSA

In this tutorial paper,the finite-horizon optimal adaptive regulation of linear and nonlinear dynamic systems with unknown system dynamics is presented in a forward-in-time manner using adaptive dynamic programming(ADP).An adaptive estimator(AE)is introduced with the idea of Q-learning to relax the requirement of system dynamics in the case of linear system,while neural network-based identifier is utilised for nonlinear systems.The time-varying nature of the solution to the Bellman/Hamilton–Jacobi–Bellman equation is handled by utilising a time-dependent basis function,while the terminal constraint is incorporated as part of the update law of the AE/Identifier in solving the optimal feedback control.Utilising an initial admissible control,the proposed optimal regulation scheme of the uncertain linear and nonlinear system yields a forward-in-time and online solution without using value and/or policy iterations.An adaptive observer is utilised for linear systems in order to relax the need for state availability so that the optimal adaptive control design depends only on the reconstructed states.Finally,the optimal control is covered for nonlinear-networked control systems where in the feedback loop is closed via a communication network.Effectiveness of the proposed approach is verified by simulation results.The end result is a variant of a roll-out scheme in ADP wherein an initial admissible policy is selected as the base policy and the control policy is enhanced using a one-time policy improvement at each sampling interval.

关键词： adaptive dynamic programming finite horizon optimal control

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DDAH1 promotes neurogenesis and neural repair in cerebral ischemia

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2097-2118页

作者： qiming Gao Pinfei Ni Yilin Wang Peiyun Huo Xiaojie Zhang Sihan Wang Fuyao Xiao Yixuan Li Wei Feng Juntao Yuan Teng Zhang Qiang Li Boyu Fan Yuhao Kan Zhirui Li Yimiao Qi Junfei Xing Zhenghong Yang Haixiao Cheng Xinran Gao Xiaoyan Feng Ming Xue Yang Liu Yumin Luo Zhongbing Lu Yuming zhao Department of Pharmacology School of Basic Medical SciencesCapital Medical UniversityBeijing 100069China Cerebrovascular Diseases Research Institute and Department of Neurology Xuanwu Hospital of Capital Medical UniversityBeijing 100053China State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of ChemistryChinese Academy of SciencesBeijing 100190China College of Life Science University of Chinese Academy of SciencesBeijing 100049China Department of Laboratory Animal School of Basic Medical SciencesCapital Medical UniversityBeijing 100069China Department of Physiology and Pathophysiology School of Basic Medical SciencesCapital Medical UniversityBeijing 100069China

Choline acetyltransferase(ChAT)-positive neurons in neural stem cell(NSC)niches can evoke adult neurogenesis(AN)and restore impaired brain function after injury,such as acute ischemic stroke(AIS).However,the relevant mechanism by which ChAT+neurons develop in NSC niches is poorly understood.Our RNA-seq analysis revealed that dimethylarginine dimethylaminohydrolase 1(DDAH1),a hydrolase for asymmetric NG,NG-dimethylarginine(ADMA),regulated genes responsible for the synthesis and transportation of acetylcholine(ACh)(Chat,Slc5a7 and Slc18a3)after stroke insult.The dual-luciferase reporter assay further suggested that DDAH1 controlled the activity of ChAT,possibly through hypoxia-inducible factor 1α(HIF-1α).KC7F2,an inhibitor of HIF-1α,abolished DDAH1-induced ChAT expression and suppressed neurogenesis.As expected,DDAH1 was clinically elevated in the blood of AIS patients and was positively correlated with AIS severity.By comparing the results among Ddah1 general knockout(KO)mice,transgenic(TG)mice and wild-type(WT)mice,we discovered that DDAH1 upregulated the proliferation and neural differentiation of NSCs in the subgranular zone(SGZ)under ischemic insult.As a result,DDAH1 may promote cognitive and motor function recovery against stroke impairment,while these neuroprotective effects are dramatically suppressed by NSC conditional knockout of Ddah1 in mice.

关键词： DDAH1 Neurogenesis Neural repair ChAT HIF-1α ACh Stroke ADMA

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不同颗粒组成与质量分数矿料的尾矿浆流变特征与模型研究

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三峡大学学报（自然科学版） 2024年第3期46卷 70-75页

作者：邓曌吴昊钟启明南京水利科学研究院南京210029

尾矿库溃坝下泄物的流变特征,是分析溃坝时空演化过程及致灾范围的重要前提.本文配制了6组不同粗细颗粒比和6组不同质量分数矿料的尾矿浆,采用旋转式流变仪分析颗粒组成和矿料质量分数对尾矿浆流变特征的影响,并分别基于屈服伪塑性流变... 详细信息

尾矿库溃坝下泄物的流变特征,是分析溃坝时空演化过程及致灾范围的重要前提.本文配制了6组不同粗细颗粒比和6组不同质量分数矿料的尾矿浆,采用旋转式流变仪分析颗粒组成和矿料质量分数对尾矿浆流变特征的影响,并分别基于屈服伪塑性流变模型和Bingham流变模型拟合得到尾矿浆的流变模型.结果表明:40%矿料质量分数条件下,尾矿浆体中细颗粒含量较少时,浆体的黏度和屈服应力很小,且剪应力随剪切速率的增大变化不大,呈现牛顿流体特征;随着细颗粒含量的增大,浆体逐渐转变成非牛顿流体,黏度和屈服应力迅速增加,并逐渐趋于指数增大趋势,剪应力也随剪切速率的增大迅速增大;矿料质量分数为10%或40%且细颗粒含量较低的尾矿浆体由于水和尾矿砂分离,其性质类似于挟砂水流,可以通过牛顿流体模型进行描述;细颗粒含量较高的尾矿浆体,Bingham模型和屈服伪塑性流体模型均可以对其流变特征进行描述.

关键词：尾矿浆流变特征拟合模型颗粒粒径

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