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Gas-surface interaction features under effects of gas-gas molecules interaction in high-speed flows

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Chinese Journal of Aeronautics 2024年第5期37卷 228-242页

作者： Ruiling TAO zhihui wang School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Understanding interactions between gas molecules and solid surface is key to the aerodynamic design of high-speed,high-altitude aerospace vehicles,but there is a large dispersion of gas-surface interaction parameters or namely accommodation coefficients.The uncertainty results partly from different considerations of the interaction between gas molecules in various experimental and numerical methods.In this study,effects of gas-gas molecules interaction are systematically discussed by comparing two different approaches of molecular dynamics simulation of high-speed argon molecules scattering on a graphite surface.The popularly-used“single scattering”approach repeats the scattering process of a single gas molecule without considering the gas-gas molecules interaction.The newly-developed“continual scattering”approach continually shoots gas molecules at the surface,considering collisions between gas molecules in addition to gas molecules’collisions with surface.Gas-surface interaction features in the two approaches are compared and discussed under various affecting factors including rarefaction degree,gas-surface interaction strength,surface temperature and incident velocity.It is shown that these two approaches usually produce different accommodation coefficients,and the corresponding mechanisms are explained.This study could help clarify some doubts about the selection of accommodation coefficients in engineering practice,and also provide an instruction on design of an appropriate molecular dynamics simulation approach.

关键词： Gas-surface interaction Molecular dynamics Accommodation coefficient Aerospace vehicles High-speed flow

Differences and similarities in radial growth of Betula species to climate change

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Journal of Forestry Research 2024年第2期35卷 176-187页

作者： Di Liu Yang An Zhao Li zhihui wang Yinghui Zhao Xiaochun wang Center for Ecological Research Key Laboratory of Sustainable Forest Ecosystem ManagementMinistry of EducationCollege of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China Changan Park in Shijiazhuang Shijiazhuang 050000People’s Republic of China Shijiazhuang Landscape Greening Engineering Project Construction Center Shijiazhuang 050000People’s Republic of China Heilongjiang Institute of Meteorological Science Harbin 150030People’s Republic of China School of Life Qufu Normal UniversityQufu 273100People’s Republic of China

Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.

关键词： Tree rings Betula platyphylla Betula costata Climate response Moving correlation Extreme drought

Effects of Environmental Factors on Corrosion Behavior of E690 Steel in Simulated Marine Environment

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 678-694页

作者： Jingjing Peng Jing Liu Shen Zhang zhihui wang Xian Zhang Kaiming Wu Collaborative Innovation Center for Advanced Steels Hubei Province Key Laboratory of Systems Science in Metallurgical ProcessThe State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan430081China

The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.

关键词： E690 steel Simulated marine environment Corrosion behavior Flow velocity Response surface methodology(RSM)

Steric hindrance modulation of hexaazatribenzanthraquinone isomers for high-capacity and wide-temperature-range aqueous proton battery

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National Science Review 2024年第4期11卷 271-282页

作者： Mingsheng Yang Yuxin Hao Bei wang Yan wang Liping Zheng Rui Li Huige Ma Xinyu wang Xiaoming Jing Hongwei Li Mengxiao Li zhihui wang Yujie Dai Guangcun Shan Mingjun Hu Jun Luo Jun Yang School of Materials Science and Engineering Beihang University Beijing Institute of Nanoenergy &Nanosystems Chinese Academy of Sciences Center on Nanoenergy Research School of Physical Science & TechnologyGuangxi University School of Chemistry and Chemical Engineering Center on Nanoenergy Research Guangxi University School of Instrumentation Science and Opto-electronics Engineering Beihang University ShenSi Lab Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of China

Organic materials with rich active sites are good candidates of high-capacity anodes in aqueous batteries,but commonly low utilization of active sites limits their capacity.Herein,two isomers,symmetric and asymmetric hexaazatribenzanthraquinone（s-HATBAQ and a-HATBAQ）,with rich active sites have been synthesized in a controllable manner.It has been revealed for the first time that a sulfuric acid catalyst can facilitate the stereoselective formation of s-HATBAQ.Attributed to the reduced steric hindrance in favor of proton insertion as well as the amorphous structure conducive to electrochemical dynamics,s-HATBAQ exhibits 1.5 times larger specific capacity than a-HATBAQ.Consequently,the electrode of s-HATBAQ with50% reduced graphene oxide（s-HATBAQ-50%rGO） delivers a record high specific capacity of405 mAh g-1in H2SO4electrolyte.Moreover,the assembled MnO2//s-HATBAQ-50%rGO aqueous proton full batteries show an exceptional cycling stability at 25℃ and can maintain ～92% capacity after1000 cycles at 0.5 A g-1at-80℃.This work demonstrates the controllable synthesis of isomers,showcases a wide-temperature-range prototype proton battery and highlights the significance of precise mole cular structure modulation in organic energy storage.

关键词： stereoisomers steric effect aqueous battery super cycling stability ultra-low temperature proton battery

Properties of sandwich-structure based Mach-Zehnder interferometer cascaded with FBG response to dual-parameter sensing

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Optoelectronics Letters 2023年第12期19卷 705-709页

作者： JIA Sumei YANG Kang LI Guoyu LI Yan wang zhihui Hebei Key Laboratory of Optical Fiber Biosensing and Communication Devices Institute of Information TechnologyHandan UniversityHandan 056005China

An all-fiber temperature and curvature sensor based on Mach-Zehnder interferometer(MZI)was proposed.The MZI was a sandwich structure which is composed of ring-core fiber(RCF),no-core fiber(NCF)and single-mode fiber(SMF).The temperature and curvature can be demodulated by the wavelength shift and the intensity variation of the dips respectively in the transmission spectrum.The measurement results show that the sensitivity of curvature is−7.88 dBm/m^(−1)in the range from 3.0 m^(−1)to 4.2 m^(−1)and the sensitivity of temperature is 53.5 pm/°C in the range from 60°C to 200°C.In addition,the cascaded FBG in the proposed structure,also sensitive to temperature,was used to monitor the fluctuation of temperature.The compact structure,the real-time temperature and the high curvature sensitivity make the sensor have the potential in the field of construction health monitoring and mining safety production.

关键词： interferometer fiber cascaded

Ambient Noise Tomography of Jinan:The Migration of Groundwater and the Formation of Geothermal Water

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Acta Geologica Sinica(English Edition) 2022年第5期96卷 1716-1728页

作者： LEI Ting LIANG Feng HAN Chen wang zhihui LI Junlun MA Yan YAO Huajian Chinese Academy of Geological Sciences Beijing 100037China SinoProbe Center Chinese Academy of Geological Sciences and China Geological SurveyBeijing 100037China Laboratory of Seismology and Physics of the Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China China University of Geosciences(Beijing) School of Geophysics and information technologyBeijing 100083China National Geophysical Observatory at Mengcheng University of Science and Technology of ChinaMengchengAnhui 233500China

Jinan is an important city in eastern China,with rich groundwater in the region.There are four famous springs in the urban area and an abundance of geothermal water in the northern part,which makes the migration of groundwater in this area a very important issue.To study the shallow shear wave velocity structure and groundwater migration in Jinan,we utilized almost a month of continuous waveform data from 175 short period seismometers deployed by the Chinese Academy of Geological Sciences,in order to calculate the cross-correlation function.We picked 7749 group dispersion curves and 6117 phase dispersion curves with a period range of 0.2–2 s.Through inversion,we obtained the fine threedimensional shear wave velocity and azimuthal anisotropy structure(0–2.4 km).Combining the results with local geological and hydrological data,the following conclusions were reached.(1)There are widespread high velocity anomalies in the region between the Qianfoshan and Wenhuaqiao faults,as well as to the east of the Wenhuaqiao Fault,which may be related to the intrusive gabbro known as the Jinan Intrusive Rock.(2)The two distinct high velocity anomalies in our model(referred to as west and east Jinan Intrusive Rock in this paper)may indicate that the Jinan Intrusive Rock was broken through crustal movement.(3)There is an obvious low velocity layer under the intrusive rock,which could be the channel of groundwater migration.The precipitation in the southern mountain region seeps down into the ground,then is blocked by the Jinan Intrusive Rock and can only progress downwards to a deeper part,where the groundwater is heated by the geothermal gradient.The heated water finally arrives at the northern part and forms geothermal water.(4)The depth of the low velocity layer beneath the Jinan Intrusive Rock varies laterally,which may indicate that the depth of the groundwater migration is different beneath the west and east Jinan Intrusive Rock.(5)There is strong azimuthal anisotropy in southern Jinan,with nearly E-W fast orientation,which m

关键词： ambient noise tomography shear wave velocity structure urban underground space Jinan groundwater Baotu Spring Park

Uncertainty entropy-based exploratory evaluation method and its applications on missile effectiveness evaluation

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Journal of Systems Engineering and Electronics 2023年第6期34卷 1602-1613页

作者： HU Jianwen wang zhihui GAO Yuan ZHU Xiaomin TIAN Yongliang LIU Hu Consulting Center for Strategic Assessment Academy of Military ScienceBeijing 100097China Army Academy of Artillery and Air Defense(Nanjing Campus) Nanjing 211132China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China College of Systems Engineering National University of Defense TechnologyChangsha 410072China

Some attributes are uncertain for evaluation work because of incomplete or limited information and knowledge.It leads to uncertainty in evaluation results.To that end,an evaluation method,uncertainty entropy-based exploratory evaluation(UEEE),is proposed to guide the evaluation activities,which can iteratively and gradually reduce uncertainty in evaluation results.Uncertainty entropy(UE)is proposed to measure the extent of uncertainty.First,the belief degree distributions are assumed to characterize the uncertainty in attributes.Then the belief degree distribution of the evaluation result can be calculated by using uncertainty theory.The obtained result is then checked based on UE to see if it could meet the requirements of decision-making.If its uncertainty level is high,more information needs to be introduced to reduce uncertainty.An algorithm based on the UE is proposed to find which attribute can mostly affect the uncertainty in results.Thus,efforts can be invested in key attribute(s),and the evaluation results can be updated accordingly.This update should be repeated until the evaluation result meets the requirements.Finally,as a case study,the effectiveness of ballistic missiles with uncertain attributes is evaluated by UEEE.The evaluation results show that the target is believed to be destroyed.

关键词： uncertainty entropy-based exploratory evaluation(UEEE) evaluation activity belief degree distribution missile effectiveness.

Effect of the coordinated reset stimulations on controlling absence seizure

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Science China(Technological Sciences) 2017年第7期60卷 985-994页

作者： wang zhihui wang QingYun Department of Dynamics and Control Beihang UniversityBeijing 100191China

Based on a macroscopic mean-field model associating with the thalamus and cerebral cortex, we investigate how the newly proposed coordinated reset stimulation(CRS) strategy controls the absence seizures as some key parameters are changed.Different from the previous stimulation processes, CRS represents the intermittent pulse current administered to different structures including cortex, specific relay nuclei(SRN) and thalamus reticular nucleus(TRN) at different time by using three different micro-electrodes. In particular, we first simulate a typical absence epilepsy activity under the combined effect of the coupling strength between inhibitory interneurons(IIN)-excitatory pyramidal neurons(EPN) and EPN-TRN pathway. And then we explore the control mechanism of different parameters of 3:2 ON-OFF CRS on spike and slow-wave discharges(SWDs)region. Through analyzing the corresponding two-dimensional bifurcation diagrams, we find CRS is effective on controlling absence seizures in proper ranges of stimulation parameters. Especially, the combination of frequency and positive input duration can inhibit the pathological area more effectively. The obtained results might be helpful to study the pathophysiology mechanism of epilepsy, although the CRS's feasibility still needs further exploration in clinical experiments.

关键词：控制作用复位生理机制 CRS 大脑皮层关键参数策略控制皮层结构

寻找不确定性:智能时代运动社会学的研究转向——基于对人工智能最新发展的思考

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西安体育学院学报 2024年第2期41卷 194-204页

作者：王智慧中国人民大学社会与人口学院北京100872 中国人民大学体育部北京100872 中国人民大学社会学理论与方法研究中心北京100872

在从ChatGPT到Sora等人工智能发展阶段性成果的推广应用下,运动参与空间、运动参与主体发生变化,对运动社会学研究产生了深刻影响。从本体、认识和方法3个层面,探讨了运动社会学在智能时代的研究转向。首先,伴随智能时代社会空间重置、... 详细信息

在从ChatGPT到Sora等人工智能发展阶段性成果的推广应用下,运动参与空间、运动参与主体发生变化,对运动社会学研究产生了深刻影响。从本体、认识和方法3个层面,探讨了运动社会学在智能时代的研究转向。首先,伴随智能时代社会空间重置、人类与机器等多主体的能动性进一步释放,运动社会学研究中以身体为载体的运动价值和意义也发生了转变。其次,运动社会学在智能时代的研究实践中,基于人与非人主体的现实/虚拟共在与互动的增加,而获得更广的研究指涉,应与时俱进地更新对其研究议题、研究伦理、解释机制的认识。第三,需客观把握定量研究、定性研究、混合研究在具体相关研究中的优势与不足,以提升运动社会学研究的人文性与科学性。

关键词：运动社会学身体人工智能虚拟表象社会关系社会空间