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Deformation prediction model of concrete face rockfill dams based on an improved random forest model

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Water Science and Engineering 2023年第4期16卷 390-398页

作者： yan-long li Qiao-gang Yin Ye Zhang Heng Zhou State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of TechnologyXi'an 710048China Power China Northwest Engineering Corporation limited Xi'an 710065China

The unique structure and complex deformation characteristics of concrete face rockfill dams(CFRDs)create safety monitoring *** study developed an improved random forest(IRF)model for dam health monitoring modeling by replacing the decision tree in the random forest(RF)model with a novel M5'model tree *** factors affecting dam deformation were preliminarily selected using the statistical model,and the grey relational degree theory was utilized to reduce the dimensions of model input ***,a deformation prediction model of CFRDs was established using the IRF *** ten-fold cross-validation method was used to quantitatively analyze the parameters affecting the IRF *** performance of the established model was verified using data from three specific measurement points on the Jishixia dam and compared with other dam deformation prediction *** point ES-10,the performance evaluation indices of the IRF model were superior to those of the M5'model tree and RF models and the classical support vector regression(SVR)and back propagation(BP)neural network models,indicating the satisfactory performance of the IRF *** IRF model also outperformed the SVR and BP models in settlement prediction at points ES2-8 and ES4-10,demonstrating its strong anti-interference and generalization *** study has developed a novel method for forecasting and analyzing dam settlements with practical ***,the established IRF model can also provide guidance for modeling health monitoring of other structures.

关键词： Dam health monitoring M5'model tree IRF Monitoring models Settlement prediction

A facile synthesis of cyano-chlorins related to chlorophyll from formyl (pyro)-pheophorbide-a by a tandem transformation of the aldehyde into a nitrile group

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Chinese Chemical Letters 2016年第5期27卷 789-794页

作者： Na Gao Jia-Zhu li yan-long li Zhen Wang Jin-Jun Wang Department of Food & Biological Engineering Wenjing College Yantai University College of Chemistry and Chemical Engineering Yantai University

A facile synthesis for cyanochlorin related to chlorophyll from a formyl-substituted chlorin, by the oxidation of methyl （pyro）pheophorbide-a, was accomplished. These readily available chlorin aldehydes were assembled together with hydroxylamine hydrochloride in a tandem process to produce the corresponding chlorin nitriles in moderate to good yields. The formation of chlorin nitrile was discussed and a possible mechanism for the corresponding cyanation reaction was tentatively proposed.

关键词： Chlorophyll-α Chlorin(Pyro)pheophorbide-α Cyanation reaction Beckmann rearrangement Tandem transformation

Experimental study on solid particle migration and production behaviors during marine natural gas hydrate dissociation by depressurization

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Petroleum Science 2023年第6期20卷 3610-3623页

作者： yan-long li Fu-long Ning Meng Xu Min-Hui Qi Jia-Xin Sun Alireza Nouri De-li Gao Neng-You Wu Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao266237ShandongChina Laboratory for Marine Mineral Resources Laoshan LaboratoryQingdao266237ShandongChina Faculty of Engineering China University of Geosciences-WuhanWuhan430074HubeiChina MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China School of Mining and Petroleum Engineering University of AlbertaEdmontonABCanada

Sand production is one of the main obstacles restricting gas extraction efficiency and safety from marine natural gas hydrate(NGH)*** migration within the NGH reservoir dominates sand production behaviors,while their relationships were rarely reported,severely constrains quantitative evaluation of sand production *** paper reports the optical observations of solid particle migration and production from micrometer to mesoscopic scales conditioned to gravel packing during depressurization-induced NGH dissociation for the first *** evolutionary modes of sand migration are established based on experimental observations,and its implications on field NGH are comprehensively *** particle migration regimes of local borehole failure,continuous collapse,wormhole expansion,extensive slow deformation,and pore-wall fluidization are proved to occur during *** types of particle migration regimes and their transmission modes during depressurization are predominantly determined by initial hydrate *** contrast,the depressurization mainly dominates the transmission rate of the particle migration ***,both the cumulative mass and the medium grain size of the produced sand decrease linearly with increasing initial methane hydrate(MH)*** gas bubble emission,expansion,and explosion during MH dissociation delay sand migration into the *** the same time,continuous water flow is a requirement for sand production during hydrate dissociation by *** experiments enlighten us that a constitutive model that can illustrate visible particle migration regimes and their transmission modes is urgently needed to bridge numerical simulation and field *** wellbore layout positions or special reservoir treatment shall be important for mitigating sand production tendency during NGH exploitation.

关键词： Natural gas hydrate Solid particle migration Sand production Sand control Sanding Hydrate exploitation

Bifurcations and Spatiotemporal Patterns in the Diffusive Nutrient-Microor ganism Model

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Acta Mathematicae Applicatae Sinica 2025年第1期41卷 162-178页

作者： Ya-di WANG Hai-long YUAN yan-ling li School of Arts and Sciences Shaanxi University of Science and TechnologyXi'an 710021China School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China School of Mathematics and Information Science Shaanxi Normal UniversityXi'an 710062China

In this paper,the diffusive nutrient-microorganism model subject to Neumann boundary conditions is *** Hopf bifurcations and steady state bifurcations which bifurcate from the positive constant equilibrium of the system are investigated in *** addition,the formulae to determine the direction of Hopf and steady state bifurcations are *** results show the existence of spatially homogeneous/nonhomogeneous periodic orbits and steady state solutions,which indicates the spatiotemporal dynamics of the *** numerical simulations are also presented to support the analytical results.

关键词： nutrient-microorganism model Hopf bifurcation steady state bifurcation simulations

Boron removal from metallurgical-grade silicon by CaO–SiO_2 slag refining

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Rare Metals 2015年第7期34卷 522-526页

作者： Kui-Xian Wei Hai-Fei Lu Wen-Hui Ma yan-long li Zhao Ding Ji-Jun Wu Yong-Nian Dai The National Engineering Laboratory for Vacuum Metallurgy and State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and Technology Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province and Engineering Research Center for Silicon Metallurgy and Silicon Materials of Yunnan Provincial Universities Kunming University of Science and Technology

Boron removal from metallurgical-grade silicon(MG-Si) using CaO–SiO2 slag was studied by employing a medium-frequency electromagnetic induction *** relationship between the optical basicity(K)of the CaO–SiO2 slag and the distribution coefficient of boron(LB) was ***, the local minimum and maximum LBvalues of 0.72 and 1.58 are obtained when K = 0.56 and K = 0.71, *** boron content in MG-Si decreases gradually with refinement time increasing, down to a minimum value of4.73 9 *** controlling step in the removal of boron from MG-Si is not the chemical reaction at the interface of the slag and ***, the controlling step is a diffusion mass transfer, in which boron impurities diffuse from molten silicon to the interface of the slag and silicon,or B2O3 formed by the chemical reaction diffuses from the slag–silicon interface to molten slag.

关键词： Metallurgical-grade silicon Boron removal Slag ref

Rac1 relieves neuronal injury induced by oxygen-glucose deprivation and re-oxygenation via regulation of mitochondrial biogenesis and function

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Neural Regeneration Research 2020年第10期15卷 1937-1946页

作者： Ping-Ping Xia Fan Zhang Cheng Chen Zhi-Hua Wang Na Wang long-yan li Qu-lian Guo Zhi Ye Department of Anesthesiology Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina National Clinical Research Center for Geriatric Disorders Central South UniversityChangshaHunan ProvinceChina Department of Anesthesiology Hainan General HospitalHaikouHainan ProvinceChina

Certain microRNAs(miRNAs)can function as neuroprotective factors after reperfusion/ischemia brain ***-142-3p can participate in the occurrence and development of tumors and myocardial ischemic injury by negatively regulating the activity of Rac1,but it remains unclear whether miRNA-142-3p also participates in cerebral ischemia/reperfusion *** this study,a model of oxygen-glucose deprivation/re-oxygenation in primary cortical neurons was established and the neurons were transfected with miR-142-3p agomirs or miR-142-3p ***-142-3p expression was down-regulated in neurons when exposed to oxygen-glucose deprivation/***-expression of miR-142-3p using its agomir remarkably promoted cell death and apoptosis induced by oxygen-glucose deprivation/re-oxygenation and improved mitochondrial biogenesis and function,including the expression of peroxisome proliferator-activated receptor-γcoactivator-1α,mitochondrial transcription factor A,and nuclear respiratory factor ***,the opposite effects were produced if miR-142-3p was *** reporter assays verified that Rac Family Small GTPase 1(Rac1)was a target gene of ***-expressed miR-142-3p inhibited NOX2 activity and expression of Rac1 and Rac1-GTPase(its activated form).miR-142-3p antagomirs had opposite effects after oxygen-glucose deprivation/*** results indicate that miR-142-3p down-regulates the expression and activation of Rac1,regulates mitochondrial biogenesis and function,and inhibits oxygen-glucose deprivation damage,thus exerting a neuroprotective *** experiments were approved by the Committee of Experimental Animal Use and Care of Central South University,China(approval No.201703346)on March 7,2017.

关键词： biogenesis ischemia/reperfusion injury microRNAs miR-142-3p mitochondria neuroprotection NOX2 oxygen-glucose deprivation Rac1

Reversible li plating regulation on graphite anode through a barium sulfate nanofibers-based dielectric separator for fast charging and high-safety lithium-ion battery

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Journal of Energy Chemistry 2025年第2期101卷 511-523页

作者： Yaxin Zhang long Cheng Ying-Jie Zhu Jin Wu Han-Ping Yu Sida Xie Dandan li Zhaohui Wang Heng li State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences College of Materials Science and Engineering Hunan University Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences

Poor li plating reversibility and high thermal runaway risks are key challenges for fast charging lithiumion batteries with graphite ***,a dielectric and fire-resistant separator based on hybrid nanofibers of barium sulfate（BS） and bacterial cellulose（BC） is developed to synchronously enhance the battery's fast charging and thermal-safety *** regulation mechanism of the dielectric BS/BC separator in enhancing the li+ion transport and li plating reversibility is revealed.（1） The Max-Wagner polarization electric field of the dielectric BS/BC separator can accelerate the desolvation of solvated li+ions,enhancing their transport kinetics.（2） Moreover,due to the charge balancing effect,the dielectric BS/BC separator homogenizes the electric field/li+ion flux at the graphite anode-separator interface,facilitating uniform li plating and suppressing li dendrite ***,the fast-charge graphite anode with the BS/BC separator shows higher Coulombic efficiency（99.0% vs.96.9%） and longer cycling lifespan（100 cycles vs.59 cycles） than that with the polypropylene（PP） separator in the constantlithiation cycling test at 2 mA *** high-loading liFePO4(15.5 mg cm-2)//graphite(7.5 mg cm-2) full cell with the BS/BC separator exhibits excellent fast charging performance,retaining 70% of its capacity after 500 cycles at a high rate of 2C,which is significantly better than that of the cell with the PP separator（retaining only 27% of its capacity after 500 cycles）.More importantly,the thermally stable BS/BC separator effectively elevates the critical temperature and reduces the heat release rate during thermal runaway,thereby significantly enhancing the battery's safety.

关键词： Fast charging Graphite anode Ion transport lithium-ion battery Separator

A sand-production control system for gas production from clayey silt hydrate reservoirs

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China Geology 2019年第2期2卷 121-132页

作者： yan-long li Neng-you Wu Fu-long Ning Gao-wei Hu Chang-ling liu Chang-yin Dong Jing-an Lu Key Laboratory for Gas Hydrate of Ministry of Natural Resources China Geological SurveyMinistry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266071China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China Faculty of Engineering China University of GeosciencesWuhan 430074China School of Petroleum Engineering China University of PetroleumQingdao 266580China Guangzhou Marine Geological Survey China Geological SurveyMinistry of Natural ResourcesGuangzhou 510075China

Sand production is a crucial problem during the process of extracting natural gas from hydrate reservoirs. To deal with sand-production problems systematically, a sand-production control system (SCS) is first proposed in this paper, specialized for pore-distributed clayey silt hydrate reservoirs. Secondly, a nodal system analysis method (NSAM) is applied to analyze the sand migration process during hydrate exploitation. The SCS is divided into three sub-systems, according to different sand migration mechanisms, and three key scientific problems and advances in SCS research in China Geological Survey are reviewed and analyzed. The maximum formation sanding rate, proper sand-control gravel size, and borehole blockage risk position were provided for clayey hydrate exploitation wells based on the SCS analysis. The SCS sub-systems are closely connected via bilateral coupling, and coordination of the subsystems is the basis of maintaining formation stability and prolonging the gas production cycle. Therefore, contradictory mitigation measures between sand production and operational systems should be considered preferentially. Some novel and efficient hydrate exploitation methods are needed to completely solve the contradictions caused by sand production.

关键词： Natural gas hydrate Hydrate exploitation Sand-production management Sand production Sand control Nodal system analysis

Blast response of full-size concrete walls with chemically reactive enamel （CRE）-coated steel reinforcement

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2016年第9期17卷 689-701页

作者： Dong-ming yan Hua-wei YIN Cheng-lin WU yan-long li Jason BAIRD Gen-da CHEN School of Civil and Architectural Engineering Zhejiang University Hangzhou 310058 China College of Civil Engineering Hunan University Changsha 410082 China Department of Civil Architectural and Environmental Engineering Missouri University of Science and Technology Rolla 654009 USA State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area Xi'an University of Technology Xi'an 710048 China Rock Mechanics and Explosives Missouri University of Science and Technology Rolla 654009 USA Center for Infrastructure Engineering Studies Missouri University of Science and Technology Rolla 654009 USA

In this study, two full-size concrete wails were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel （CRE） coating in improving their mechanical behavior under blast loading： one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene （TNT） charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface sWain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests.

关键词： Chemically reactive enamel (CRE) coating Blast loading Crack pattern Bond strength Finite element model