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A super sandstorm altered the abundance and composition of airborne bacteria in Beijing

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Journal of Environmental Sciences 2024年第10期144卷 35-44页

作者： Fanxuan Xia Zhuo chen Enze tian Jinhan Mo Beijing Key Laboratory of Indoor Air Quality Evaluation and Control Department of Building ScienceTsinghua UniversityBeijing 100084China Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China Key Laboratory of Coastal Urban Resilient Infrastructures(Shenzhen University) Ministry of EducationShenzhen 518060China Key Laboratory of Eco Planning&Green Building(Tsinghua University) Ministry of EducationBeijing 100084China

Sandstorm,which injects generous newly emerging microbes into the atmosphere covering cities,adversely affects the air quality in built ***,few studies have examined the change of airborne bacteria during severe sandstorm *** this work,we analyzed the airborne bacteria during one of the strongest sandstorms in East Asia onMarch 15th,2021,which affected large areas of China and *** characteristics of the sandstorm were compared with those of the subsequent clean and haze *** composition of the bacterial community of air samples was investigated using quantitative polymerase chain reaction(qPCR)and high-throughput sequencing *** the sandstorm,the particulate matter(PM)concentration and bacterial richnesswere extremely high(PM_(2.5):207μg/m^(3);PM_(10):1630μg/m^(3);5700 amplicon sequence variants/m^(3)).In addition,the sandstorm brought 10 pathogenic bacterial genera to the atmosphere,posing a grave hazard to human *** the sandstorm subsided,small bioaerosols(0.65–1.1μm)with a similar bacterial community remained suspended in the atmosphere,bringing possible long-lasting health risks.

关键词： Airborne bacteria Sandstorm Bioaerosol Haze Pathogen

Review on bio-inspired flight systems and bionic aerodynamics

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Chinese Journal of Aeronautics 2021年第7期34卷 170-186页

作者： Jiakun HAN Zhe HUI Fangbao tian Gang chen School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Engineering and Information Technology University of New South Wales CanberraACT 2600Australia The Key Laboratory of Aerodynamics Noise Control Mianyang 621000China

Humans’initial desire for flight stems from the imitation of flying creatures in *** excellent flight performance of flying animals will inevitably become a source of inspiration for ***-inspired flight systems have become one of the most exciting disruptive aviation *** review is focused on the recent progresses in bio-inspired flight systems and bionic ***,the development path of Biomimetic Air Vehicles(BAVs)for bio-inspired flight systems and the latest mimetic progress are *** advances of the flight principles of several natural creatures are then introduced,from the perspective of bionic ***,several new challenges of bionic aerodynamics are proposed for the autonomy and intelligent development trend of the bio-inspired smart *** review will provide an important insight in designing new biomimetic air vehicles.

关键词： Bio-inspired flight systems Biomimetic air vehicle Bionic aerodynamics Micro air vehicle

An adaptive dwell time scheduling model for phased array radar based on three-way decision

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Journal of Systems Engineering and Electronics 2020年第3期31卷 500-509页

作者： LI Bo tian Linyu chen Daqing LIANG Shiyang School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China School of Engineering London South Bank UniversityLondon SE10AAUK

Real-time resource allocation is crucial for phased array radar to undertake multi-task with limited resources,such as the situation of multi-target tracking,in which targets need to be prioritized so that resources can be allocated accordingly and effectively.A three-way decision-based model is proposed for adaptive scheduling of phased radar dwell *** the model,the threat posed by a target is measured by an evaluation function,and therefore,a target is assigned to one of the three possible decision regions,i.e.,positive region,negative region,and boundary region.A different region has a various priority in terms of resource demand,and as such,a different radar resource allocation decision is applied to each region to satisfy different tracking accuracies of *** addition,the dwell time scheduling model can be further optimized by implementing a strategy for determining a proper threshold of three-way decision making to optimize the thresholds adaptively in *** advantages and the performance of the proposed model have been verified by experimental simulations with comparison to the traditional twoway decision model and the three-way decision model without threshold *** experiential results demonstrate that the performance of the proposed model has a certain advantage in detecting high threat targets.

关键词： phased array radar resource scheduling three-way decision threat assessment

Electric-Circuit Realization of Fast Quantum Search

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Research 2021年第1期2021卷 868-875页

作者： Naiqiao Pan tian chen Houjun Sun Xiangdong Zhang Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements of Ministry of Education Beijing Key Laboratory of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of Millimeter Wave and Terahertz Techniques School of Information and ElectronicsBeijing Institute of TechnologyBeijing 100081China

Quantum search algorithm,which can search an unsorted database quadratically faster than any known classical algorithms,has become one of the most impressive showcases of quantum *** has been implemented using various quantum ***,we demonstrate both theoretically and experimentally that such a fast search algorithm can also be realized using classical electric *** classical circuit networks to perform such a fast search have been *** has been shown that the evolution of electric signals in the circuit networks is analogies of quantum particles randomly walking on graphs described by quantum *** searching efficiencies in our designed classical circuits are the same to the quantum *** classical circuit networks possess good scalability and stability,the present scheme is expected to avoid some problems faced by the quantum ***,our findings are advantageous for information processing in the era of big data.

关键词： theory. quantum faster

A Correction Factor-Based General Thermal Resistance Formula for Heat Exchanger Design and Performance Analysis

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Journal of Thermal Science 2021年第3期30卷 892-901页

作者： HAO Junhong chen Qun LI Xia ZHAO tian Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

Methods for the analysis of heat exchangers with various flow arrangements modeling,design,and performance are essential for heat transfer system modeling and its integration with other energy system *** paper proposes the use of the linear-transfer law for the heat exchanger design and performance analysis as a function of the thermal resistance related to the ratio of a linear temperature difference to the total heat transfer ***,we derived a correction factor that represents the influence of the flow arrangement on the heat transfer performance by the effective thermal conductance,as a function of correction factor,heat transfer coefficient,and surface *** on the effective thermal conductance,we propose the hot-end NTU and cold-end NTU for deriving a standardized and general thermal resistance formula for different types of heat exchangers by the combination of the correction factor with linear-transfer ***,for parallel-flow,cross-flow,and 1-2 Tubular Exchanger Manufacturers Association(TEMA)E shell-and-tube heat exchangers,we derived and obtained alternative correction factor expressions without introducing any *** cases about heat exchanger design and performance analysis show that the calculation processes using the correction factor-based general thermal resistance are straightforward without any iteration and the calculation results are ***,the experimental validation shows that the general thermal resistance formula is appropriate for analyzing the heat transfer *** is,the correction factor-based general thermal resistance formula provides a standardized model for heat exchanger analysis and heat transfer/integrated energy system modeling using the heat current method.

关键词： general thermal resistance formula correction factor heat current model linear-transfer law heat exchanger

Investigation of the Laminar Premixed n-Propylamine Flame

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Journal of Thermal Science 2022年第3期31卷 854-866页

作者： LI Wang chen Jintao YANG Jiuzhong tian Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China National Synchrotron Radiation Laboratory University of Science and TechnologyHefei230029China

The laminar premixed n-propylamine(NPA)flame with equivalence ratio of 1.70 has been investigated at 4666.28 Pa using tunable synchrotron photoionization and molecular-beam mass spectrometry *** structures and mole fractions of 40 species were ***,allylamine,butadiyne,vinylacetylene,1,3-butadiene,1-butene,2-butene,n-butyl radical,1,3-cyclopentadiene,cyclopentene,2-pentene,benzene,toluene,ethylbenzene,2-propen-1-imine,cyclopropanimine,pyrrole,2-butenenitrile and n-butylamine were newly identified in the amine *** fraction profiles of some species including reactants,intermediates and products in the NPA flame were *** and N_(2)were observed as the primary N-containing products in the NPA flame,which was different from the result that NO was the major N-containing products in previous studies of nitrogen *** bond energies of NPA were calculated through quantum chemistry calculations on the basis of density functional theory at the CBS-QB3 *** showed that the CH_(3)CH_(2)-CH_(2)NH_(2)bond was the weakest and NPA mainly decomposed to CH_(2)NH_(2)and C_(2)H_(5)*** H-abstractions at C_(α)by OH/O(NPA+OH=CH_(3)CH_(2)CHNH_(2)+H_(2)O and NPA+O=CH_(3)CH_(2)CHNH_(2)+OH)had significant promoting effects on NPA *** N conversion chain of NPA under flame conditions was proposed and detailed analysis with respect to intermediates especially the nitrogen-containing species were *** results will enrich the understanding of NPA flame and are essential to further establish the kinetic mechanism.

关键词： n-propylamine low-pressure laminar premixed flame intermediates mole fraction quantum chemistry calculation molecular beam mass spectrometry

Lateral compression and energy absorption of foamed concrete-filled polyethylene circular pipe as yielding layer for high geo-stress soft rock tunnels

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International Journal of Mining Science and Technology 2022年第5期32卷 1087-1096页

作者： Chaoxuan Zhang Xianjun Tan Hongming tian Weizhong chen State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

Foamed concrete as energy absorption material for high geo-stress soft rock tunnels has been proven to be feasible due to its high compressibility and ***,the lengthy curing and defoaming problems caused by the cast-in-place method of large-volume foamed concrete remain *** this study,we propose a novel energy absorber composed of foamed concrete-filled polyethylene(FC-PE)pipe and analyze its deformation and energy absorption capacity via quasi-static lateral compression *** show that FC-PE pipes exhibit typical three-stage deformation characteristics,comprising the elastic stage,the plastic plateau,and the densification ***,the plateau stress,energy absorption,and specific energy absorption of the specimens are 0.81–1.91 MPa,164–533 J,and 1.4–3.6 J/g,*** the density of the foamed concrete increases,the plateau stress and energy absorption increase ***,the length of the plastic plateau and energy absorption efficiency ***,based on the vertical slice method,progressive compression of core material,and the 6 plastic hinges deformation mechanism of the pipe wall,a theoretical calculation method for effective energy absorption is established and achieves good agreement with experimental results,which is beneficial to the optimization of the composite structure.

关键词： Soft rock Yielding layer Foamed concrete Polyethylene pipe Lateral compression Energy absorption

A Feature Optimized Deep Learning Model for Clinical Data Mining

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Chinese Journal of Electronics 2020年第3期29卷 476-481页

作者： WU tianshu chen Shuyu tian Yingming WU Peng College of Computer Science Chongqing University College of Automation Chongqing University

the Artificial intelligence(AI) has gradually changed from frontier technology to practical application with the continuous progress of deep learning technology in recent years. In this paper, the Random forest(RF) algorithm is adopted to preprocess and optimize the feature subset of ICU data sets. Then these optimized feature subsets are used as input of Long shortterm memory(LSTM) deep learning model, and the early disease prediction of ICU inpatients is carried out by the method of neural network deep learning. Experiments show that this prediction method has higher prediction accuracy compared with other machine learning and deep learning models.

关键词： Clinical data mining Random forests(RF) Long short-term memory(LSTM)

Decode protein-metabolite regulatory network: one MIDAS at a time

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Signal Transduction and Targeted Therapy 2023年第9期8卷 3896-3898页

作者： tian Liu chen Gao Department of Pharmacology and Systems Physiology University of CincinnatiCincinnatiOHUSA

In a recent study published in Science,Hicks et *** Mass spectrometry integrated with equilibrium dialysis for the discovery of allostery systematically(MIDAS)to explore protein-metabolite interactome and have revealed previously unknown regulation for lactate dehydrogenase.1 This report brings an exciting new approach to address a long-standing challenge in *** functions are orchestrated by an interactive network of molecular constituents,the physical interactions between proteins and other molecular entities,such as DNA,RNA,and *** basic vocabulary for the book of life,these interactions are the fundamental mechanisms for complex physiology and diseases.

关键词： network such she