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Estimation of Fine Dust Particles Distribution in Machining Workshop Based on COwZ Model

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 346-354页

作者： REN fan liu Fei State Key Laboratory of Mechanical Transmission Chongqing University Chongqing 400030 China

Fine dust particles （diameter is less than 2.5 μm） generated during machining processes,especially dry cutting,are harmful to operators,because they remain suspended in the air for long time and have marked concentration gradients in *** studies about cutting dust source states and indoor air quality prediction have been ***,few researches focus on the distribution state of the cutting dust,dynamic status of fine dust particles,and environment estimating of the machining *** machining workshops have diversified architectural structures,complex working conditions,so the dust emission is sensitive *** to these features,after analysis of the static and dynamic influence factors,this paper proposes a method and establishes a model to estimate the fine dust particles distribution based on COwZ （COMIS （conjunction of multizone infiltration specialists） with sub-zones） model when only dry cutting is processed just needing various working *** two key technologies are discussed：the description of the machine tools using sub-zones of COwZ model considering the local obstacle effects of machine tools themselves;description and implementation of dynamic process of cutting dust emission with a new concept of equivalent source *** last,multi-point experiments in a hybrid ventilation machining workshop prove the method is *** agreement was observed between the estimation results and the experimental measurements for the investigated *** proposed method can supply reference data for green manufacturing.

关键词： COwZ model dry cutting fine dust particles dust emission green manufacturing

COVID-19 and cardiovascular diseases

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Journal of Molecular Cell Biology 2021年第3期13卷 161-167页

作者： fan liu Feng liu Lu Wang State Key Laboratory of Experimental Hematology Institute of Hematology and Blood Diseases HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeTianjin 300020China State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The coronavirus disease 2019(COVID-19)remains a global public health *** being caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),besides the lung,this infectious disease also has severe implications in the cardiovascular *** this review,we summarize diverse clinical complications of the heart and vascular system,as well as the relevant high mortality,in COVID-19 *** inflammation and angiotensin-converting enzyme 2-involved signaling networking in SARS-CoV-2 infection and the cardiovascular system may contribute to the manifestations of cardiovascular ***,integration of clinical observations and experimental findings can promote our understanding of the underlying mechanisms,which would aid in identifying and treating cardiovascular injury in patients with COVID-19 appropriately.

关键词： COVID-19 cardiovascular diseases SARS-CoV-2 ACE2 systemic inflammation

Impact of thermal stratification on airborne transmission risk of SARS-CoV-2 in various indoor environments

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Building Simulation 2023年第7期16卷 1159-1172页

作者： fan liu Zhiwen Luo Hua Qian School of Environment and Architecture University of Shanghai for Science and TechnologyShanghaiChina Welsh School of Architecture Cardiff UniversityCardiffUK School of Energy and Environment Southeast UniversityNanjingChina

There exist various vertical temperature gradients in different-type buildings.A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is *** this work,the airborne transmission risk of SARS-CoV-2 in different thermally stratified indoor environments is assessed using our previously developed airborne infection risk *** show that the vertical temperature gradients in office building,hospital,classroom,*** within the range of−0.34 to 3.26℃/*** large space such as coach station,airport terminal,and sport hall,the average temperature gradient ranges within 0.13–2.38℃/m in occupied zone(0–3 m);in ice rink with special requirements of indoor environment,the temperature gradient is higher than those in the above indoor *** existence of temperature gradients causes multi-peaks of the transmission risk of SARS-CoV-2 with distancing,and our results show that in office,hospital ward and classroom,the second peak of the transmission risk is higher than 10^(−3)in most contact scenarios,while most being lower than 10^(−6)in large spaces like coach station and *** work is expected to provide some guidance on specific intervention policies in relation to the types of indoor environments.

关键词： SARS-CoV-2 temperature gradient different-type buildings transmission risk

Digital virtual flight testing and evaluation method for flight characteristics airworthiness compliance of civil aircraft based on HQRM

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Chinese Journal of Aeronautics 2015年第1期28卷 112-120页

作者： liu fan Wang Lixin Tan Xiangsheng School of Aeronautic Science and Engineering Beihang University

In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system（EFCS） equipped civil aircraft, digital virtual flight testing and evaluation method based on handling qualities rating method（HQRM）is proposed. First, according to HQRM, flight characteristics airworthiness requirements of civil aircraft in EFCS failure states are determined. On this basis, digital virtual flight testing model,comprising flight task digitized model, pilot controlling model, aircraft motion and atmospheric turbulence model, is used to simulate the realistic process of a pilot controlling an airplane to perform assigned flight tasks. According to the simulation results, flight characteristics airworthiness compliance of the airplane can be evaluated relying on the relevant regulations for handling qualities（HQ） rating. Finally, this method is applied to a type of passenger airplane in a typical EFCS failure state, and preliminary conclusions concerning airworthiness compliance are derived quickly. The research results of this manuscript can provide important theoretical reference for EFCS design and actual airworthiness compliance verification of civil aircraft.

关键词： civil aircraft compliance preliminary verification pilot turbulence realistic passenger concerning

THE CHARACTERISTICS AND ESTIMATION OF FLOW THROUGH A SINGLE ROUGH-WALLED FRACTURE

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Journal of Hydrodynamics 2012年第3期24卷 315-322页

作者： liu Qing-quan fan Hong-guang Laboratory-of Environmental Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190China

The flow through a single fracture is numerically studied by means of the Fluent Software. The results show that the roughness of the fracture significantly affects the hydraulic conductivity in the fracture as compared with the cubic law model widely used to describe the flow between two smooth parallel plates. A new model is proposed in this paper, the non-symmetric sinusoidal fracture model, to simulate the flow in a real fracture. This model involves two sinusoidal-varying walls with different phases to replace the flat planes in the cubic law model. The relationships between the effective hydraulic apertures and the phase retardation for different relative amplitudes and wavelengths are numerically investigated. A simple expression of the effective hydraulic aperture of the fracture is obtained, together with the law of the effective hydraulic aperture against the amplitude, the phase retardation and the wavelength of two sinusoidal-varying walls.

关键词： fracture seepage cubic law effective hydraulic aperture non-symmetric sinusoidal fracture

Nitric Oxide Signaling in Plant Responses to Abiotic Stresses

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Journal of Integrative Plant Biology 2008年第10期50卷 1238-1246页

作者： Weihua Qiao liu-Min fan Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing 100871 China

Nitric oxide （NO） plays important roles in diverse physiological processes in plants. NO can provoke both beneficial and harmful effects, which depend on the concentration and location of NO in plant cells. This review is focused on NO synthesis and the functions of NO in plant responses to abiotic environmental stresses. Abiotic stresses mostly induce NO production in plants. NO alleviates the harmfulness of reactive oxygen species, and reacts with other target molecules, and regulates the expression of stress responsive genes under various stress conditions.

关键词： abiotic stress H2O2 nitric oxide reactive oxygen species signal transduction.

Distributed Finite-Time Integral Sliding-Mode Control for Multi-Agent Systems with Multiple Disturbances Based on Nonlinear Disturbance Observers

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Journal of Systems Science & Complexity 2021年第3期34卷 995-1013页

作者： YANG Yize liu fan YANG Hongyong LI Yuling liu Yuanshan School of Information and Electrical Engineering Ludong UniversityYantai 264025China

This paper proposes a finite-time consensus control algorithm based on nonlinear integral sliding-mode control for second-order multi-agent systems(MASs)with mismatched and matched ***,a nonlinear finite-time disturbance observer is established to estimate the states and mismatched disturbances of the ***,a dynamic integral sliding-mode(ISM)surface is designed by employing the estimates of mismatched ***,based on the designed ISM and disturbance observer,the discontinuous or continuous campsite control protocols are respectively developed to guarantee the consensus for MASs in finite time with active anti-disturbance ***,numerical simulation results illustrate the effectiveness of the proposed consensus control algorithm.

关键词： Finite-time consensus integral sliding-mode control mismatched disturbances multiagent systems super-twisting algorithm

Actin Dynamics Regulates Voltage-Dependent Calcium-Permeable Channels of the Vicia faba Guard Cell Plasma Membrane

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Journal of Integrative Plant Biology 2009年第10期51卷 912-921页

作者： Wei Zhang liu-Min fan National Laboratory of Plant Physiology and Biochemistry College of Biological Sciences China Agricultural University Beijing 100094 China School of Life Sciences Shandong University Jinan 250100 China peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing 100871 China

Free cytosolic Ca^2＋（[Ca^2＋]cyt） is an ubiquitous second messenger in plant cell signaling, and [Ca^2＋]cyt elevation is associated with Ca^2＋-permeable channels in the plasma membrane and endomembranes regulated by a wide range of stimuli. However, knowledge regarding Ca^2＋ channels and their regulation remains limited in planta. A type of voltage- dependent Ca^2＋-permeable channel was identified and characterized for the Vicia faba L. guard cell plasma membrane by using patch-clamp techniques. These channels are permeable to both Ba^2＋ and Ca^2＋, and their activities can be inhibited by micromolar Gd^3＋. The unitary conductance and the reversal potential of the channels depend on the Ca^2＋ or Ba^2＋ gradients across the plasma membrane. The inward whole-cell Ca^2＋（Ba^2＋） current, as well as the unitary current amplitude and NPo of the single Ca^2＋ channel, increase along with the membrane hyperpolarization. Pharmacological experiments suggest that actin dynamics may serve as an upstream regulator of this type of calcium channel of the guard cell plasma membrane. Cytochalasin D, an actin polymerization blocker, activated the NPo of these channels at the single channel level and increased the current amplitude at the whole-cell level. But these channel activations and current increments could be restrained by pretreatment with an F-actin stabilizer, phalloidin. The potential physiological significance of this regulatory mechanism is also discussed.

关键词： actin dynamics calcium-permeable channels guard cell patch clamp plasma membrane Vicia faba.

Machine learning-based stiffness optimization of digital composite metamaterials with desired positive or negative Poisson's ratio

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Theoretical & Applied Mechanics Letters 2023年第6期13卷 424-431页

作者： Xihang Jiang fan liu Lifeng Wang Department of Mechanical Engineering Stony Brook UniversityNYUSA Brigham and Women’s Hospital Harvard Medical SchoolBostonMA 02115USA

Mechanical metamaterials such as auxetic materials have attracted great interest due to their unusual properties that are dictated by their ***,these architected materials usually have low stiffness because of the bending or rotation deformation mechanisms in the *** this work,a convolutional neural network(CNN)based self-learning multi-objective optimization is performed to design digital composite *** CNN models have undergone rigorous training using randomly generated two-phase digital composite materials,along with their corresponding Poisson's ratios and stiffness *** the CNN models are used for designing composite material structures with the minimum Poisson's ratio at a given volume fraction ***,we have designed composite materials with optimized stiffness while exhibiting a desired Poisson's ratio(negative,zero,or positive).The optimized designs have been successfully and efficiently obtained,and their validity has been confirmed through finite element analysis *** self-learning multi-objective optimization model offers a promising approach for achieving comprehensive multi-objective optimization.

关键词： Digital composite materials Metamaterials Machine learning Convolutional neural network(CNN) Poisson's ratio Stiffness