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Flow instability of supercritical hydrocarbon fuel in a multi-channel cooling system

Chinese Journal of Aeronautics 2024年第2期37卷 283-295页

作者： yichao JIN Kun WU Xuejun FAN Institute of Applied Physics and Computational Mathematics Beijing 100094China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Thermally-induced flow instabilities are a critical issue in multi-channel regenerative cooling *** particular,the interactions between Density-Wave Oscillations(DWO)and Flow Maldistribution(FMD)can result in complex and disastrous instability *** study investigates the instability behaviors of hydrocarbon fluid in a four-channel system with a constant heat flux ratio using both frequency-and time-domain *** the heat flux increases,the in-tube flow sequentially destabilizes in each channel and converges to new equilibrium states,leading to the emergence of FMD *** also causes the system eigenvalue to change repeatedly from negative to positive rather than increasing ***,the system eigenvalues are between those of the two most unstable channels,indicating that the stability behavior of the entire system is dictated by the most unstable *** FMD occurs,flow oscillations are activated in channels with weak stability,and the in-tube flow is observed to evolve into various flow patterns,including stable flow,self-sustained oscillation,oscillation divergence,quasiperiodic oscillation,and oscillation *** novel instability mode of oscillation excursion involves a spontaneous transition of operating *** oscillates from an equilibrium state and then stabilizes at a new operational state after oscillation-induced ***,the newfound stable state may also be only temporary,with the in-tube flow regressing to the initial state,resulting in quasi-periodic oscillation.

关键词： Cooling Supercritical fluids Hydrocarbons Flow instability Flow maldistribution Density-wave oscillations

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A General Simulation Method for Complex Deformation of Irregular-Shaped Origami Configurations

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Acta Mechanica Solida Sinica 2024年第1期37卷 90-98页

作者： Zhaochen Dong yichao Zhu Xu Guo State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116023China

Most existing treatments for origami-folding simulations have focused on regular-shaped *** article aims to introduce a general strategy for simulating and analyzing the deformation process of irregular shapes by means of computational capabilities *** better simulate origami deformation with folding orders,the concept of plane follow-up is introduced to achieve automated computer simulation of complex folding patterns,thereby avoiding intersection and penetration between *** on the evaluation criteria such as the lowest storage energy with tightening and the fastest pace from tightening to unfolding,the optimal crease distribution patterns for four irregular(‘N’-,‘T’-,‘O’-,and‘P’-shaped)origami configurations are then presented under five *** the dimensions of the origami are fixed,it is discovered that simpler folding patterns lead to faster deformation of the origami *** the folding complexity is fixed,higher strain energy results in more rapid origami expansion.

关键词： Irregular-shaped origami Complex deformation Computer-aided origami design General simulation

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Symbology of Feynman integrals from twistor geometries

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 44-59页

作者： Song He Jiahao Liu yichao Tang Qinglin Yang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China International Centre for Theoretical Physics Asia-Pacific Beijing 100049 Peng Huanwu Center for Fundamental Theory Hefei 230026China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We study the symbology of planar Feynman integrals in dimensional regularization by considering geometric configurations in momentum twistor space corresponding to their leading singularities(LS). Cutting propagators in momentum twistor space amounts to intersecting lines associated with loop and external dual momenta, including the special line associated with the point at infinity, which breaks dual conformal symmetry. We show that cross-ratios of intersection points on these lines, especially those on the infinity line, naturally produce symbol letters for Feynman integrals in D = 4-2∈, which include and generalize their LS. At one loop, we obtain all symbol letters using intersection points from quadruple cuts for integrals up to pentagon kinematics with two massive corners, which agree perfectly with canonical differential equation(CDE) results. We then obtain all two-loop letters, for up to four-mass box and one-mass pentagon kinematics, by considering more intersections arising from two-loop cuts. Finally we comment on how cluster algebras appear from this construction, and importantly how we may extend the method to non-planar integrals.

关键词： Feynman integrals symbol letters twistor geometry

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Continuous preparation of strong and tough PVA nanocomposite fibers by mechanical stretching-assisted salting-out treatment

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Nano Research 2024年第4期17卷 3156-3163页

作者： Hang Chen Guangze Yang Yingzhi Sun yichao Xu Mingjie Liu Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191China Research Institute for Frontier Science Beihang UniversityBeijing 100191China International Research Institute for Multidisciplinary Science Beihang UniversityBeijing 100191China

Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant *** we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out *** prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high *** the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical *** presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.

关键词： poly(vinyl alcohol)(PVA)nanofibers oriented structure ultrastrong and stiff mechanical vibration transmission salting out continuous production

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Remarkable enhancement of gas selectivity on organosilica hybrid membranes using urea-modulated metal-organic framework nanoparticles

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 83-92页

作者： Yayun Zhao Dechuan Zhao Chunlong Kong yichao Lin Xuezhen Wang Liang Chen Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China Collaboration Innovation Center for Tissue Repair Material Engineering Technology China West Normal UniversityNanchong 637009China

Metal-organic framework/organosilica hybrid membranes on tubular ceramic substrates have shown great potential for the implementation of membrane technology in practical gas separation projects due to their higher permeance compared to commercial ***,the selectivities of the reported membranes are ***,we have incorporated urea-modulated metal-organic frameworks into organosilica membranes to greatly enhance its separation *** urea-modulated metal-organic frameworks exhibit less-defined edges of crystallographic facets and high defect *** can be well-dispersed in the organosilica layer,which substantially suppresses the interfacial defects between metal-organic frameworks and organosilica,which is beneficial for improving the selectivity of membranes for gas *** results have shown that the enhanced ideal selectivity of H_(2)/CH_(4) was 165 and that of CO_(2)/CH_(4) was 43,with H_(2) permeance of about 1.25×10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) and CO_(2) permeance of 3.27×10^(−7) mol·m^(−2)·s^(−1)·Pa^(−1) at 0.2 MPa and 25℃.In conclusion,the high level of hybrid membranes can be used to separate H_(2)(or CO_(2))from the binary gas mixture H_(2)/CH_(4)(or CO_(2)/CH_(4)),which is important for gas separation in practical ***,the simple and feasible modulation of metal-organic framework is a promising strategy to tune different metal-organic frameworks for membranes according to the actual demands.

关键词： ZIF-8 nanocrystals urea organosilica hybrid membrane enhanced separation performance

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Effects of long-term fencing on soil microbial community structure and function in the desert steppe,China

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Journal of Arid Land 2024年第3期16卷 431-446页

作者： PAN Yaqing KANG Peng QU Xuan RAN yichao LI Xinrong Shapotou Desert Research and Experiment Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Biological Science and Engineering North Minzu UniversityYinchuan 750021China

One of the goals of grazing management in the desert steppe is to improve its ***,relatively little is known about soil microbe communities in the desert steppe ecosystem under grazing *** this study,we investigated the diversity and aboveground biomass of Caragana korshinskii *** communities in long-term fencing and grazing areas,combined with an analysis of soil physical-chemical properties and genomics,with the aim of understanding how fence management affects plant-soil-microbial inter-relationships in the desert steppe,*** results showed that fence management(exclosure)increased plant diversity and aboveground biomass in *** shrub area and effectively enhanced soil organic carbon(233.94%),available nitrogen(87.77%),and available phosphorus(53.67%)*** well,the Shannon indices of soil bacteria and fungi were greater in the fenced ***-soil changes profoundly affected the alpha-and beta-diversity of soil *** management also altered the soil microbial community structure,significantly increasing the relative abundances of Acidobacteriota(5.31%-8.99%),Chloroflexi(3.99%-5.58%),and Glomeromycota(1.37%-3.28%).The soil bacterial-fungal co-occurrence networks under fence management had higher complexity and *** on functional predictions,fence management significantly increased the relative abundance of bacteria with nitrification and nitrate reduction functions and decreased the relative abundance of bacteria with nitrate and nitrite respiration *** relative abundances of ecologically functional fungi with arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and saprotrophs also significantly increased under fence *** addition,the differential functional groups of bacteria and fungi were closely related to plant-soil *** results of this study have significant positive implications for the ecological restoration and reconstruction of dry desert steppe and simila

关键词： desert steppe fence management Caragana korshinskii soil physical-chemical property soil microorganism

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ASTSDL:predicting the functionality of incomplete programming code via an AST-sequence-based deep learning model

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Science China(Information Sciences) 2024年第1期67卷 86-104页

作者： Yaoshen YU Zhiqiu HUANG Guohua SHEN Weiwei LI yichao SHAO College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Collaborative Innovation Center of Novel Software Technology and Industrialization Key Laboratory of Safety-Critical Software Ministry of Industry and Information Technology

Code recommendation systems have been widely used in helping developers implement unfamiliar programming *** existing code recommenders or code search engines can retrieve relevant code rapidly with high accuracy,however,they cannot recommend any code outside similar *** propose an approach to predict the functionality of incomplete programming code by using syntactical information,and providing a list of potential functionalities to guess what the developers want,in order to increase the diversity of *** this paper,we propose a deep learning model called ASTSDL,which uses a sequencebased representation of source code to predict *** extract syntactical information from the abstract syntax tree(AST) of the source code,apply a deep learning model to capture the syntactic and sequential information,and predict the functionality of the source code *** experimental results demonstrate that ASTSDL can effectively predict the functionality of incomplete code with an accuracy above 84% in the top-10 list,even if there is only half of the complete code.

关键词： functionality prediction incomplete programming code syntactical information code representation model deep learning algorithm

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A robust triaxial localization method of AE source using refraction path

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International Journal of Mining Science and Technology 2024年第4期34卷 521-530页

作者： yichao Rui Jie Chen Jiongkun Chen Jiadong Qiu Zilong Zhou Wenzhong Wang Jinyang Fan State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China School of Resources and Safety Engineering Chongqing UniversityChongqing 400044China School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China School of Resources and Safety Engineering Central South UniversityChangsha 410083China Coal Geological Exploration Institute of Gansu Lanzhou 730030China

Acoustic emission(AE)localization algorithms based on homogeneous media or single-velocity are less accurate when applied to the triaxial localization *** the end,a robust triaxial localization method of AE source using refraction path is ***,the control equation of the refraction path is established according to the sensor coordinates and arrival ***,considering the influence of time-difference-of-arrival(TDOA)errors,the residual of the governing equation is calculated to estimate the equation ***,the refraction points in different directions are solved using Snell’s law and orthogonal ***,the source coordinates are iteratively solved by weighted correction *** feasibility and accuracy of the proposed method are verified by pencil-lead breaking *** simulation results show that the new method is almost unaffected by the refraction ratio,and always holds more stable and accurate positioning performance than the traditional method under different ratios and scales of TDOA outliers.

关键词： Acoustic emission(AE) Source localization Robust method Refraction paths Weight estimations

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Biomolecule capturing and sensing on 2D transition metal dichalcogenide canvas

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Nano Research Energy 2023年第1期2卷 45-57页

作者： yichao bai Linxuan Sun Qiangmin Yu Yu Lei Bilu Liu Institute of Materials Research Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen InstituteTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Since the isolation of graphene in 2004,two-dimensional(2D)materials such as transition metal dichalcogenide(TMD)have attracted numerous interests due to their unique van der Waals structure,atomically thin body,and thickness-dependent *** recent years,the applications of TMD in public health have emerged due to their large surface area and high surface sensitivities,as well as their unique electrical,optical,and electrochemical *** this review,we focus on state-of-the-art methods to modulate the properties of 2D TMD and their applications in ***,this review provides methods for designing and modulating 2D TMD via defect engineering and morphology control to achieve multi-functional surfaces for molecule capturing and ***,we compare the 2D TMD-based biosensors with the traditional sensing systems,deepening our understanding of their action ***,we point out the challenges and opportunities of 2D TMD in this emerging area.

关键词： 2D materials transition metal dichalcogenide property modulation biomolecule capturing sensing

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Small particles,big effects:How nanoparticles can enhance plant growth in favorable and harsh conditions

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Journal of Integrative Plant Biology 2024年第7期66卷 1274-1294页

作者： Jie Wang Honghong Wu yichao Wang Wuwei Ye Xiangpei Kong Zujun Yin Zhengzhou Research Base State Key Laboratory of Cotton Bio‐breeding and Integrated UtilizationSchool of Agricultural SciencesZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Cotton Bio‐breeding and Integrated Utilization Institute of Cotton ResearchChinese Academy of Agricultural SciencesAnyang 455000China National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070China School of Engineering Design and Built EnvironmentWestern Sydney UniversityPenrith NSW 2751Australia Western Agricultural Research Center Chinese Academy of Agricultural SciencesChangji 831100China The Key Laboratory of Plant Development and Environmental Adaptation Biology Ministry of EducationCollege of Life SciencesShandong UniversityQingdao 266237China

By 2050,the global population is projected to reach 9 billion,underscoring the imperative for innovative solutions to increase grain yield and enhance food *** has emerged as a powerful tool,providing unique solutions to this ***(NPs)can improve plant growth and nutrition under normal conditions through their high surface-to-volume ratio and unique physical and chemical ***,they can be used to monitor crop health status and augment plant resilience against abiotic stresses(such as salinity,drought,heavy metals,and extreme temperatures)that endanger global *** of NPs can enhance stress tolerance mechanisms in plants,minimizing potential yield losses and underscoring the potential of NPs to raise crop yield and *** review highlights the need for a comprehensive exploration of the environmental implications and safety of nanomaterials and provides valuable guidelines for researchers,policymakers,and agricultural *** thoughtful stewardship,nanotechnology holds immense promise in shaping environmentally sustainable agriculture amid escalating environmental challenges.

关键词： abiotic stress agricultural defense system nano-particles nanotechnology oxidative stress reactive oxygen species toxicity

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