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High-fidelity numerical simulation of unsteady cavitating flow around a hydrofoil

Journal of Hydrodynamics 2023年第1期35卷 1-16页

作者： Nan Xie yu-meng tang Yang-wei Liu School of Energy and Power Engineering Beihang UniversityBeijing100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing100191China

Cavitation is a widespread and detrimental phenomenon in hydraulic machinery, therefore, it requires to be accurately predicted. In this study, large eddy simulation (LES), scale-adaptive simulation (SAS) and grid-adaptive simulation (GAS) are employed to investigate the unsteady cavitating flow around a NACA0009 hydrofoil. The prediction accuracy of GAS, SAS, both using the shear-stress transport (SST) k — ω model as baseline turbulence model, is validated by comparing with experimental and LES results. The cavity behaviors and turbulence fields are analyzed systematically. Results show that the GAS gives a more reasonable turbulent viscosity and accurately predicts the periodic evolution of typical vortical structures of cavitating flow, such as tip leakage vortex cavitation, tip separation vortex cavitation, leading-edge cavitation, and trailing-edge vortex. The time-averaged cavity volume, volume fluctuation amplitude, and characteristic frequencies of cavities predicted by the GAS are very closed to the LES, while the SAS fails to accurately capture these cavity characteristics. Furthermore, the local trace criterion is applied to extract the vortical structures and to analyze the swirling patterns of the tip leakage vortex. Multi-scale vortical structures in LES are well identified by local trace criterion. The prediction accuracy of the SAS method for small-scale vortical structures, such as the vortex shedding on the suction side and the vortex rope around the tip leakage vortex, is obviously insufficient, while the GAS has a higher accuracy in predicting vortex shedding. The tip leakage vortex and induced vortex extracted from GAS are also closer to that of LES in both swirling patterns and scale.

关键词： Tip leakage vortex cavitation leading-edge cavitation large eddy simulation(LES) grid-adaptive simulation scale-adaptive simulation

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Whole-Brain Map of Long-Range Monosynaptic Inputs to Different Cell Types in the Amygdala of the Mouse

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Neuroscience Bulletin 2020年第11期36卷 1381-1394页

作者： Jia-yu Fu Xiao-Dan yu Yi Zhu Shi-Ze Xie meng-yu tang Bin yu Xiao-Ming Li Center for Neuroscience and Department of Neurology of Second Affiliated Hospital Zhejiang University School of MedicineHangzhou 310058China NHC and CAMS Key Laboratory of Medical Neurobiology Center for Brain Science and Brain-Inspired IntelligenceGuangdong-Hong Kong-Macao Greater Bay AreaJoint Institute for Genetics and Genome Medicine between Zhejiang University and University of TorontoHangzhou 310058China

The amygdala,which is involved in various behaviors and emotions,is reported to connect with the whole ***,the long-range inputs of distinct cell types have not yet been ***,we used a retrograde trans-synaptic rabies virus to generate a whole-brain map of inputs to the main cell types in the mouse *** identified 37 individual regions that projected to neurons expressing vesicular glutamate transporter 2,78 regions to parvalbumin-expressing neurons,104 regions to neurons expressing protein kinase C-δ,and 89 regions to somatostatin-expressing *** amygdala received massive projections from the isocortex and *** nuclei,such as the caudate-putamen and the CA1 field of the hippocampus,exhibited input preferences to different cell types in the ***,we identified several novel input areas,including the substantia innominata and zona *** findings provide anatomical evidence to help understand the precise connections and diverse functions of the amygdala.

关键词： Basolateral amygdala Central amygdala Rabies virus retrograde tracing Glutamatergic GABAergic Mouse

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Somatostatin-Positive Neurons in the Rostral Zona Incerta Modulate Innate Fear-Induced Defensive Response in Mice

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Neuroscience Bulletin 2023年第2期39卷 245-260页

作者： Shan Lin meng-yue Zhu meng-yu tang Mi Wang Xiao-Dan yu Yi Zhu Shi-Ze Xie Dan Yang Jiadong Chen Xiao-Ming Li Department of Neurobiology and Department of Neurology of the Second Afliated Hospital Zhejiang University School of MedicineHangzhou 310058China NHC and CAMS Key Laboratory of Medical Neurobiology MOE Frontier Science Center for Brain Research and Brain-Machine IntegrationSchool of Brain Science and Brian MedicineZhejiang UniversityHangzhou 310058China Center for Brain Science and Brain-Inspired Intelligence Research Units for Emotion and Emotion DisordersChinese Academy of Medical SciencesChina/Guangdong-Hong Kong-Macao Greater Bay AreaJoint Institute for Genetics and Genome Medicine between Zhejiang University and the University of TorontoHangzhou 310058China

Defensive behaviors induced by innate fear or Pavlovian fear conditioning are crucial for animals to avoid threats and ensure *** zona incerta(ZI)has been demonstrated to play important roles in fear learning and fear memory,as well as modulating auditory-induced innate defensive ***,whether the neuronal subtypes in the ZI and specific circuits can mediate the innate fear response is largely ***,we found that somatostatin(SST)-positive neurons in the rostral ZI of mice were activated by a visual innate fear *** inhibition of SST-positive neurons in the rostral ZI resulted in reduced flight responses to an overhead looming *** activation of SST-positive neurons in the rostral ZI induced fear-like defensive behavior including increased immobility and *** addition,we demonstrated that manipulation of the GABAergic projections from SST-positive neurons in the rostral ZI to the downstream nucleus reuniens(Re)mediated fear-like defensive *** trans-synaptic tracing also revealed looming stimulus-activated neurons in the superior colliculus(SC)that projected to the Re-projecting SST-positive neurons in the rostral ZI(SC-ZIrSST-Re pathway).Together,our study elucidates the function of SST-positive neurons in the rostral ZI and the SC-ZIrSST-Re tri-synaptic circuit in mediating the innate fear response.

关键词： Innate fear Zona incerta Somatostatinpositive neurons Looming stimulus Defensive behavior

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Fully polarized Compton scattering in plane waves and its polarization transfer

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Matter and Radiation at Extremes 2024年第3期9卷 45-56页

作者： Suo tang yu Xin meng Wen Mamat Ali Bake Baisong Xie College of Physics and Optoelectronic Engineering Ocean University of ChinaQingdaoShandong 266100China Department of Physics Hubei UniversityWuhan 430062China Xinjiang Key Laboratory of Solid State Physics and Devices School of Physics Science and TechnologyXinjiang UniversityUrumqi 830017China Key Laboratory of Beam Technology of the Ministry of Education and College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China

Fully polarized Compton scattering from a beam of spin-polarized electrons is investigated in plane-wave backgrounds in a broad intensity region from the perturbative to the nonperturbative *** the perturbative regime,polarized linear Compton scattering is considered for investigating polarization transfer from a single laser photon to a scattered photon,and in the high-intensity region,the polarized locally monochromatic approximation and locally constant field approximation are established and are employed to study polarization transfer from an incoming electron to a scattered *** numerical results suggest an appreciable improvement of about 10%in the scattering probability in the intermediate-intensity region if the electron’s longitudinal spin is parallel to the laser *** longitudinal spin of the incoming electron can be transferred to the scattered photon with an efficiency that increases with laser intensity and collisional *** collision between an optical laser with frequency1 eV and a 10 GeV electron,this polarization transfer efficiency can increase from about 20%in the perturbative regime to about 50%in the nonperturbative regime for scattered photons with relatively high energy.

关键词： polarized scattered transfer

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Predicting submerged vegetation drag with a machine learning-based method

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Journal of Hydrodynamics 2024年第3期36卷 534-545页

作者： meng-yang Liu Hong-wu tang Sai-yu yuan Jing Yan College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Key Laboratory of Hydrologic-Cycle and Hydrodynamic-System of Ministry of Water Resources Hohai UniversityNanjing210098China

Accurate estimation of the drag forces generated by vegetation stems is crucial for the comprehensive assessment of the impact of aquatic vegetation on hydrodynamic processes in aquatic *** coupling relationship between vegetation layer flow velocity and vegetation drag makes precise prediction of submerged vegetation drag forces particularly *** present study utilized published data on submerged vegetation drag force measurements and employed a genetic programming(GP)algorithm,a machine learning technique,to establish the connection between submerged vegetation drag forces and flow and vegetation *** using the bulk velocity,U,as the reference velocity scale to define the drag coefficient,C_(d),and stem Reynolds number,the GP runs revealed that the drag coefficient of submerged vegetation is related to submergence ratio(H^(*)),aspect ratio(d^(*)),blockage ratio(ψ^(*)),and vegetation density(λ).The relation between vegetation stem drag forces and flow velocity is implicitly embedded in the definition of C_(d).Comparisons with experimental drag force measurements indicate that using the bulk velocity as the reference velocity,as opposed to using the vegetation layer average velocity,U_(v),eliminates the need for complex iterative processes to estimate U_(v)and avoids introducing additional errors associated with U_(v)*** approach significantly enhances the model’s predictive capabilities and results in a simpler and more user-friendly formula expression.

关键词： Drag coefficient genetic programming algorithm submerged vegetation flow resistance cylinder array

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The effect of Ti and Zr content on the structure,mechanics and energy-release characteristics of Ti—Zr—Ta alloys

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Defence Technology（防务技术） 2024年第1期31卷 343-350页

作者： Jia-yu meng Jing-zhi He Bin Zhang Jin Chen Shun Li Dun Niu yu tang Xi’an Modern Chemistry Research Institute Xi'an710065China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China

Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage *** this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were *** microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of *** the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of *** evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta *** synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation *** as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually *** higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.

关键词： Energetic structural materials Ti-Zr-Ta Multi-element alloy Energy release characteristics

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A Deep Mesencephalic Nucleus Circuit Regulates Licking Behavior

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Neuroscience Bulletin 2022年第6期38卷 565-575页

作者： Di Zheng Jja-yu Fu meng-yu tang iao-Dan yu Yi Zhu Chen Jie Shen Chun-yue Li Shi-Ze Xiel Shan Lin Minmin Luo Xiao-Ming Li Department of Neurobiology and Department of Neurology of Second Affliated HospitalZhejiang University School of MedicineHangzhou 310058China NHC and CAMS Key Laboratory of Medical Neurobiology MOE Frontier Science Center for Brain Research and Brainmachine IntegrationSchool of Brain Science and Brian MedicineZhejiang UniversityHangzhou 310058China National Institute of Biological Sciences(NIBS) Bejing 102206China Chinese Institute for Brain Research Beijing 102206China School of Life Sciences Tsinghua UniversityBejing 100084China Center for Brain Science and Brain-Inspired Intelligence Research Units for Emotion and Emotion DisordersChinese Academy of Medical SciencesChina/Guangdong-Hong Kong-Macao Greater Bay AreaJoint Institute for Genetics and Genome Medicine Between Zhejiang University and University of TorontoHangzhou 310058.China

Licking behavior is important for water *** deep mesencephalic nucleus(DpMe)has been implicated in instinctive ***,whether the DpMe is involved in licking behavior and the precise neural circuit behind this behavior remains ***,we found that the activity of the DpMe decreased during water *** of vesicular glutamate transporter 2-positive(VGLUT2+)neurons in the DpMe resulted in increased water ***-expressing(SST+),but not protein kinase C-expressing(PKC-8+),GABAergic neurons in the central amygdala(CeA)preferentially innervated DpMe VGLUT2+*** SST+neurons in the CeA projecting to the DpMe were activated at the onset of licking *** of these CeA SST+GABAergic neurons,but not PKC-8+GABAergic neurons,projecting to the DpMe was sufficient to induce licking behavior and promote water *** findings redefine the roles of the DpMe and reveal a novel CeAssT_DpMevcLUT?cireuit that regulaes icking behavior and promotes water intake.

关键词： Midbrain Amygdala Licking Neural Circuit Optogenetics

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Improving photochemical indicators for attributing ozone sensitivities in source apportionment analysis

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Journal of Environmental Sciences 2024年第9期143卷 235-246页

作者： Xiaohui Du Wei tang Zhongzhi Zhang Yang yu Yang Li Ling Huang Greg Yarwood Fan meng Atmospheric Environment Institute Chinese Research Academy of Environmental SciencesBeijing 100012China College of Water Sciences Beijing Normal UniversityBeijing 100857China Asia Center for Air Pollution Research United Nations Environment Programme Asia and the Pacific OfficeNishi-kuNiigata-shi 9502144Japan School of Environmental and Chemical Engineering Shanghai UniversityShanghai 200444China Ramboll NovatoCalifornia 94945USA

Comprehensive Air Quality Model with extensions(CAMx)-Decoupled Direct Method(DDM)simulations of first-order ozone(O_(3))sensitivity to nitrogen oxides(NO_(x))and volatile organic compounds(VOCs)emissions were performed and combined with modelled P_(H_(2)O_(2))/P_(HNO_(3))ratios to obtain a range of thresholds for determining O_(3)-sensitivity regimes for different areas of *** the new threshold ranges for photochemical indicators,the method for determining O_(3)formation in the Ozone Source Apportionment Technology(OSAT)module within CAMx was improved by a dynamically varied threshold of P_(H_(2)O_(2))/P_(HNO_(3))*** O_(3)concentration contributions in the newly added transition regime were apportioned to NO_(x)and VOCs emissions in proportion to the relationship between the P_(H_(2)O_(2))/P_(HNO_(3))ratio and first-order O_(3)*** source contributions of O_(3)concentrations from different emission sectors from June to September 2019 were compared using the original and improved *** results showed that the O_(3)concentration contributions changed significantly in the NO_(x)-limited regime,with a maximum decrease of 21.89%,while the contributions increased by up to 7.57%in the VOC-limited regime,and were within 15μg/m^(3)in the transition *** modified OSAT module enabled a more sophisticated attribution of O_(3)to precursor emissions and may have far-reaching implications for informing O_(3)pollution control policy.

关键词： O_(3) modeling O_(3)-sensitivity regimes Ozone source apportionment technology Photochemical indicators

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Species-specific and generalized allometric biomass models for eight Fagaceae species in the understory of evergreen broadleaved forests in subtropical China

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Journal of Forestry Research 2024年第4期35卷 156-170页

作者： Shengwang meng Qianyanzhou Ecological Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101People’s Republic of China

Quantifying the biomass of saplings in the regeneration component is critical for understanding biogeochemical processes of forest ***,accurate allometric equations have yet to be developed in sufficient *** develop species-specific and generalized allometric equations,154 saplings of eight Fagaceae tree species in subtropical China’s evergreen broadleaved forests were *** dendrometric variables,root collar diameter(d),height(h),and crown area(ca)were applied in the model by the weighted nonlinear seemingly unrelated regression *** only d as an input variable,the species-specific and generalized allometric equations estimated the aboveground biomass reasonably,with R _(adj)^(2) values generally>*** h and/or ca improved the fitting of some biomass components to a certain *** equations showed a relatively large coefficient of variation but comparable bias to species-specific *** in the absence of species-specific equations at a given location are generalized equations for mixed species *** developed regression equations can be used to accurately calculate the aboveground biomass of understory Fagaceae regeneration trees in China’s subtropical evergreen broadleaved forests.

关键词： Allometry Aboveground biomass Additivity Regeneration Subtropical China

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Prediction of ball-on-plate friction and wear by ANN with data-driven optimization

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Friction 2024年第6期12卷 1235-1249页

作者： Alexander KOVALEV yu TIAN Yonggang meng State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

For training artificial neural network(ANN),big data either generated by machine or measured from experiments are used as input to"learn"the unspecified functions defining the *** experimental data are fed directly into the optimizer allowing training to be performed according to a predefined loss *** predict sliding friction and wear at mixed lubrication conditions,in this study a specific ANN structure was so designed that deep learning algorithms and data-driven optimization models can be *** ball-on-plate friction and wear data were analyzed using the specific training procedure to optimize the weights and biases incorporated into the neural layers of the ANN,and only two independent experimental data sets were used during the ANN optimization *** the training procedure,the ANN is capable to predict the contact and hydrodynamic pressure by adapting the output data according to the tribological condition implemented in the optimization algorithm.

关键词： machine learning deep learning artificial neural network mixed lubrication

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