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Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

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Journal of Thermal Science 2024年第1期33卷 126-137页

作者： sun Feng XIE Gongnan School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics

Organic thin-film transistors and related devices in life and health monitoring

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Nano Research 2024年第2期17卷 426-444页

作者： Chenfang sun Tie Wang Tianjin Key Laboratory of Drug Targeting and Bioimaging Life and Health Intelligent Research InstituteTianjin University of TechnologyTianjin 300384China

The early determination of disease-related biomarkers can significantly improve the survival rate of ***,a series of explorations for new diagnosis technologies,such as optical and electrochemical methods,have been devoted to life and health *** thin-film transistor(OTFT),as a state-of-the-art nano-sensing technology,has attracted significant attention from construction to application owing to the merits of being label-free,low-cost,facial,and rapid detection with multi-parameter ***,interference from non-specific adsorption is inevitable in complex biological samples such as body liquid and exhaled gas,so the reliability and accuracy of the biosensor need to be further improved while ensuring sensitivity,selectivity,and ***,we overviewed the composition,mechanism,and construction strategies of OTFTs for the practical determination of disease-related biomarkers in both body fluids and exhaled *** results show that the realization of bio-inspired applications will come true with the rapid development of high-effective OTFTs and related devices.

关键词： organic thin-film transistors biosensors biomarkers organic bioelectronics organic semiconductors healthcare

Effect of fore/aft-loaded rotor on compressor stability under inlet circumferential distortion

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Chinese Journal of Aeronautics 2024年第5期37卷 199-213页

作者： Dakun sun Benhao GU Fangfei NING Dengke XU Xiaofeng sun School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-engine Beihang UniversityBeijing 102206China

A modified small perturbation stability prediction model for axial compressors with circumferential inlet distortions is established and applied to investigate the effect of fore/aft-loaded rotor on compressor stability under circumferentially distorted inlet *** inlet total pressure distribution downstream of the distortion screen is measured in experiments and employed for simulations which are implemented via time-space spectral *** stall inception prediction results via the stability model indicate that the compressor with aft-loaded rotor not only performs better in terms of stability under uniform inlet,but also maintains a larger stability margin under circumferentially distorted *** experiments for compressors with fore-loaded and aft-loaded rotor are respectively carried *** results validate the reliability of numerical simulations and the predicted conclusion that the aft-loaded rotor is beneficial for compressor ***,the ability of the developed theoretical model for compressor stability prediction under circumferential distortions is *** addition,dynamic pressure signals at rotor tip measured in experiments illustrate that the circumferential distortion has little effect on the compressor stall pattern.

关键词： Axial compressor stability Inlet distortion Blade loading Small perturbation Time-space spectral method

New perspectives on deep carbon cycling

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Science China Earth Sciences 2024年第8期67卷 2411-2422页

作者： Weidong sun Center of Deep Sea Research Key Laboratory of Ocean Observation and ForecastingInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China University of Chinese Academy of Sciences Beijing 100049China

The proto-atmosphere serves as a crucial starting point for the carbon *** based on atmospheric data from Mars and Venus suggest that Earth's proto-atmosphere contained>110 bar of CO_(2)and>2.6 bar of *** protoatmosphere had over 1000 bar of water vapor during the magma ocean stage,assuming the proto-ocean had a volume of two oceans of *** this stage both water and carbon dioxide were in a supercritical state at the magma-atmosphere *** serpentinization reactions occurred due to rock-water interaction,producing abundant ***,nitrogen is reduced to ammonia,and carbon dioxide to methane,forming carbonate *** proto-atmosphere dominated by methane,ammonia,and hydrogen formed a significant amount of amino acids through *** process is essential not only to the origin of life,but also to the early carbon-nitrogen cycle on *** the Hadean eon,a large amount of CO_(2)was sequestered as carbonate and organic ***,it mainly entered the deep mantle through mantle overturn or *** the mantle transition zone,carbonate undergoes“Redox freezing”,where carbonate is reduced to diamond through oxidation of ferrous iron in the *** the lower mantle,Fe^(2+)undergoes disproportionation reactions,forming Fe^(3+)and metallic *** these,Fe^(3+)mainly resides in bridgmanite,thereby increasing the oxygen fugacity of the lower mantle,while metallic iron falls to the Earth's *** distribution of carbon in the mantle is crucial for deep carbon *** density curves of diamond and mantle peridotite melt intersect at the bottom of the mantle transition zone(about 660 km).This density crossover leads to the accumulation of diamond during the magma ocean *** materials such as subducting slabs enter the lower mantle,compensatory upwelling of lower mantle material *** enters the upper mantle,decomposes,releasing Fe^(3+)ions and oxidizes diamond

关键词： Carbon cycling Proto-atmosphere Amino acids Subduction initiation Passive margin subduction Atmospheric carbon dioxide

Multilayer polyethylene separator with enhanced thermal properties for safe lithium-ion batteries Author links open overlay panel

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Particuology 2024年第8期91卷 29-37页

作者： Ying Jiang Chen sun Feilong Dong Haiming Xie Liqun sun National&Local United Engineering Laboratory for Power Battery Department of ChemistryNortheast Normal UniversityChangchun130024China

The separator plays an important part in battery safety and *** separators are widely used in commercial Lithium-ion batteries(LIBs),owing to their excellent properties,but they suffer from serious thermal shrinkage and poor electrolyte ***,a multilayer separator(ASPESA)is developed by coating two thin layers of low-density polyethylene(LDPE)and Al_(2)O_(3)on both sides of a polyethylene membrane using a facile and environmentally friendly casting *** ASPESA separator demonstrates a shutdown function at 120℃and shows enhanced thermal stability under 185℃,with a small thermal shrinkage of 1%.Meanwhile,the LDPE and Al_(2)O_(3)layers can improve the electrolyte wettability and electrolyte uptake(407.23%).The multilayer ASPESA separator delivers an excellent cycle performance in LiFePO_(4)||Li cells with a discharge capacity of 144.5 mAh g^(-1)after 900 cycles,with a high-capacity retention of 98.9%(compared to the 5th cycle).Therefore,the multilayer ASPESA separator has great utilization potential as a high-safety separator in LIBs.

关键词： Low-density polyethylene microspheres Al_(2)O_(3)particles Thermal shutdown High safety Lithium-ionbatteries

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基于RTK定位的图像差分跑道异物检测

电子测量与仪器学报 2020年第10期32卷 51-56页

作者：张怡孙永荣刘梓轩鲁海枰赵伟南京航空航天大学导航研究中心南京211106

机场跑道异物是威胁航空器飞行安全的重要因素之一,开展跑道异物的自动检测研究是有效保障航空器飞行安全的必然要求。针对异物检测问题,首先提出了基于DGPS(differential GPS)定位的图像差分异物检测方法,通过载波相位差分(RTK)技术获... 详细信息

机场跑道异物是威胁航空器飞行安全的重要因素之一,开展跑道异物的自动检测研究是有效保障航空器飞行安全的必然要求。针对异物检测问题,首先提出了基于DGPS(differential GPS)定位的图像差分异物检测方法,通过载波相位差分(RTK)技术获取道面图像的高精度位置信息,对同一位置的两幅图像进行对齐操作以满足图像差分的条件,接着采用直方图规定化的方法来完成亮度矫正,再通过差分实现异物检测,最后进行了实验验证。实验结果表明,该方法可有效检测尺寸不小于2 cm×2 cm的异物。

关键词：异物检测图像差分 RTK技术图像对齐亮度矫正

Adaptive Event-Triggered Time-Varying Output Group Formation Containment Control of Heterogeneous Multiagent Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1398-1409页

作者： Lihong Feng Bonan Huang Jiayue sun Qiuye sun Xiangpeng Xie College of Information Science and Engineering Northeastern UniversityShenyang 110819China College of Automation and College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing 210023China IEEE

In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed *** MAS is composed of a number of tracking leaders,formation leaders and followers,where two different types of leaders are used to provide reference trajectories for movement and to achieve certain formations,***,compen-sators are designed whose states are estimations of tracking lead-ers,based on which,a controller is developed for each formation leader to accomplish the expected ***,two event-triggered compensators are proposed for each follower to evalu-ate the state and formation information of the formation leaders in the same group,***,a control protocol is designed for each follower,utilizing the output information,to guide the output towards the convex hull generated by the forma-tion leaders within the ***,the triggering sequence in this paper is decomposed into two sequences,and the inter-event intervals of these two triggering conditions are provided to rule out the Zeno ***,a numerical simulation is intro-duced to confirm the validity of the proposed results.

关键词： Adaptive control event-triggered mechanisms for-mation containment(FC) heterogeneous multiagent systems time-varying group formation.

Heat Recuperation for the Self-Condensing CO_(2)Transcritical Power Cycle

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Journal of Thermal Science 2024年第5期33卷 1630-1641页

作者： PAN Lisheng SHI Weixiu sun Yin sun Yiwei WEI Xiaolin State Key Laboratory of High-temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Environment and Energy Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China

The supercritical CO_(2)Brayton cycle has potential to be used in electricity generation occasions with its advantages of high efficiency and compact *** on a so-called self-condensing CO_(2)transcritical power cycle,a model was established and four different layouts of heat recuperation process were analyzed,a without-recuperation cycle,a post-recuperation cycle,a pre-recuperation cycle and a re-recuperation *** results showed that the internal normal cycle's share of the whole cycle increases with increasing the cooling pressure and decreasing the final cooled *** load in the supercritical heater decreases with increasing the cooling *** perspective of performance,the re-recuperation cycle and the pre-recuperation cycle have similar thermal efficiency which is much higher than other two *** thermal efficiency and net power output have a maximum value with the cooling pressure,except in the condition with the final cooled temperature of 31℃.Considering both the complexity and the economy,the pre-recuperation cycle is more applicable than the other *** 35℃of the final cooled temperature,the thermal efficiency of the pre-recuperation cycle reaches the peak 0.34 with the cooling pressure of 8.4 MPa and the maximum net power output is 2355.24 kW at 8.2 MPa of the cooling pressure.

关键词： CO_(2)transcritical power cycle heat recuperation process self-condensing

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多星座组合导航系统定位性能研究

弹箭与制导学报 2009年第2期29卷 16-19页

作者：吴玲孙永荣陈达立俞晓磊南京航空航天大学自动化学院南京210016 空军驻江西地区军事代表室南昌330024

通过对我国不同纬度地区三个典型城市以及同一地区不同高度角下,从可见卫星数目及PDOP值两个角度,对GPS、GLONASS和GALILEO单星座系统以及其组合系统的定位性能进行了对比分析。仿真结果表明:与单星座系统相比,多星座组合系统的可见星... 详细信息

通过对我国不同纬度地区三个典型城市以及同一地区不同高度角下,从可见卫星数目及PDOP值两个角度,对GPS、GLONASS和GALILEO单星座系统以及其组合系统的定位性能进行了对比分析。仿真结果表明:与单星座系统相比,多星座组合系统的可见星数目大大增加,PDOP值明显减小,在我国不同地区都具有良好的定位性能,并且在卫星高度角较高时仍可以接收四颗以上的卫星,其PDOP值也能达到导航定位的要求。

关键词：多星座组合组合导航定位性能