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Programmable microfluidics for dynamic multiband camouflage

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Microsystems & Nanoengineering 2023年第2期9卷 275-282页

作者： Chunzao Feng Mingran Mao Xiaohui Zhang yutian Liao Xiaohui Xiao Huidong Liu Kang Liu MOE Key Laboratory of Hydraulic Machinery Transients School of Power and Mechanical EngineeringWuhan UniversityWuhan 430072 HubeiChina

Achieving multiband camouflage covering both visible and infrared regions is challenging due to the broad bandwidth and differentiated regulation demand in diverse *** this work,we propose a programmable microfluidic strategy that uses dye molecules in layered fluids to manipulate visible light-and infrared-semitransparent solvent to manipulate infrared *** three primary fluid inputs,we achieve 64 chromaticity values and 8 emissivities from 0.42 to *** view of the wide tuning range,we demonstrate that the microfluidic flm can dynamically change its surface reflectance to blend into varying backgrounds in both visible and infrared ***,we fabricate the microfluidic device in a textile form and demonstrate its ability to match exactly with the colors of natural leaves of different seasons in the full hyperspectrum *** the broadband modulation and ease of operation,the programmable microfluidic strategy provides a feasible approach for smart optical surfaces in long-span optical spectra.

关键词： multiband tuning visible

Investigate the nonuniformity of low-energy electron beam with large cross-sections

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Science China(Technological Sciences) 2012年第4期55卷 997-1000页

作者： REN Jie HUANG JianMing ZHANG yutian LI DeMing ZHU NanKang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Suzhou CNNC Huadong Radiation Co. LtdSuzhou 215200China

Over the past decades, low-energy electron accelerators have been used worldwide for surface curing and sterilization. The beam nonuniformity is an important parameter of the low-energy electron beam with large cross-sections. A simple and accurate measurement system of nonuniformity for the low-energy electron beam with large cross-sections was developed. The main concept consists in the measurement of nonuniformity, which is realized by using a linear actuator to drive two scanning wires through the beam's cross-sections at a fixed speed. The beam distribution can be obtained by sending/collecting the current signals to/from the Data Acquisition (DAQ) software on a laptop by a USB DAQ card. This device is very convenient for the performance testing of a new accelerator at the manufacturer's site. The distribution of the homemade low voltage electron accelerator EBS-300-50 was measured and evaluated.

关键词： low-energy electron beam large cross-sections electron beam industry accelerator beam nonuniformity measurement

The anisotropy of suprathermal electrons in the Martian ionosphere

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Earth and Planetary Physics 2024年第3期8卷 459-471页

作者： yutian Cao Jun Cui XiaoShu Wu WenJun Liang RuiQi Fu HaoYu Lu Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519082China Key Laboratory of Geospace Environment University of Science&Technology of ChinaChinese Academy of SciencesHefei 230026China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China School of Space and Environment Beihang UniversityBeijing 102206China

Suprathermal electrons are an important population of the Martian ionosphere, either produced by photoionization of atmospheric neutrals or supplied from the Solar Wind (SW). This study is dedicated to an in-depth investigation of the pitch angle distribution of suprathermal electrons at two representative energies, 19−55 eV and 124−356 eV, using the extensive measurements made by the Solar Wind Electron Analyzer on board the Mars Atmosphere and Volatile Evolution. Throughout the study, we focus on the overall degree of anisotropy, defined as the standard deviation of suprathermal electron intensity among different directions which is normalized by the mean omni-directional intensity. The available data reveal the following characteristics: (1) In general, low energy electrons are more isotropic than high energy electrons, and dayside electrons are more isotropic than nightside electrons;(2) On the dayside, the anisotropy increases with increasing altitude at low energies but remains roughly constant at high energies, whereas on the nightside, the anisotropy decreases with increasing altitude at all energies;(3) Electrons tend to be more isotropic in strongly magnetized regions than in weakly magnetized regions, especially on the nightside. These observations indicate that the anisotropy is a useful diagnostic of suprathermal electron transport, for which the conversion between the parallel and perpendicular momenta as required by the conservation of the first adiabatic invariant, along with the atmospheric absorption at low altitudes, are two crucial factors modulating the observed variation of the anisotropy. Our analysis also highlights the different roles on the observed anisotropy exerted by suprathermal electrons of different origins.

关键词： Mars ionosphere suprathermal electron pitch angle distribution

Investigation of MHD power generation with supersonic non-equilibrium RF discharge

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Chinese Journal of Aeronautics 2016年第4期29卷 855-862页

作者： Yang Pengyu Zhang Bailing Li Yiwen Wang yutian Duan Chengduo Fan Hao Gao Ling Science and Technology on Plasma Dynamics Laboratory Air Force Engineering University China Aerodynamics Research and Development Center Science and Technology on Combustion Internal Flow and Thermo-Structure Laboratory Astronautics School Northwestern Polytechnical University

Magnetohydrodynamic (MHD) power generation with supersonic non-equilibrium plasma is demonstrated. Capacitively coupled radio frequency (RF) discharge (6 MHz, maximum continual power output of 200 W) was adopted to ionize the Mach number 3.5 (650 m/s), 0.023 kg/m(3) airflow. In a MHD channel of 16 mm x 10 mm x 20 mm, MHD open voltage of 10 V is realized in the magnetic field of 1.25 T, and power of 0.12 mW is extracted steadily and continuously in the magnetic field of 1 T. The reasons for limited power generation are proposed as: low conductivity of RF discharge; large touch resistance between MHD electrode and plasma; strong current eddies due to flow boundary layer. In addition, the cathode voltage fall is too low to have obvious effects on MHD power generation. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd.

关键词： Magnetohydrodynamic Non-equilibrium plasma Power generation Radio frequency discharge Supersonic flow

Distribution of Pacific-origin water in the region of the Chukchi Plateau in the Arctic Ocean in the summer of 2003

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Acta Oceanologica Sinica 2005年第6期24卷 12-24页

作者： SHI Jiuxin CAO Yong ZHAO Jinping GAO Guoping JIAO yutian LI Shujiang First Institute of Oceanography State Oceanic Administration Qingdao 266061 China College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China

The upper ocean thermohaline structures in the region of the Chukchi Plateauare analyzed with the hydrographic data collected by the Chinese National Arctic Research Expeditionin the summer of 2003. Three types of the Pacific-origin water were found in the upper ocean,Alaska Coastal Water (ACW), summer Bering Sea Water (sBSW) and winter Bering Sea Water (wBSW) areindicated by two maximums temperature and one minimum temperature, piling up from the upper to thelower respectively. The extreme warm ACW with a maximum temperature of 1.62℃ was found in thesouthwestern Canada Basin at a depth of about 50 m. A pathway of the ACW into the basin from itsadjacent area did not existed in the expedition period. So it is speculated that the extreme warmfeature of the ACW was formed locally in 2003. The relative weak ACW occurred to the east of theChukchi Cap and in the southern Chukchi Abyssal Plain. The latter one might originate from a warmdownwelling that existed in a small canyon at the shelf break of the Chukchi Sea. The sBSW withoutthe ACW was found only at the southwestern flank of the Chukchi Cap. The ACW and the sBSW were notfound in the northernmost station at 81°N,which indicates the north boundary of the upperPacific-origin water in the Canada Basin. The wBSW, which existed in all deep stations, was exactlyuniform at temperature. The difference of the core potential temperature of the wBSW in the deepregions is only 0.08℃.

关键词： alaska coastal water bering sea water water mass arctic ocean

Structural insights into the Oryza sativa cation transporters HKTs in salt tolerance

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Journal of Integrative Plant Biology 2024年第4期66卷 700-708页

作者： Ran Gao yutian Jia Xia Xu Peng Fu Jiaqi Zhou Guanghui Yang State Key Laboratory of Plant Environmental Resilience Frontiers Science Center for Molecular Design BreedingCollege of Biological SciencesChina Agricultural UniversityBeijing 100193China

The high-affinity potassium transporters(HKTs),selectively permeable to either Na^(+)alone or Na^(+)/K^(+),play pivotal roles in maintaining plant Na^(+)/K^(+)*** their involvement in salt tolerance is widely reported,the molecular underpinnings of Oryza sativa HKTs remain *** this study,we elucidate the structures of OsHKT1;1 and OsHKT2;1,representing two distinct classes of rice *** dimeric assembled OsHKTs can be structurally divided into four *** the dimer interface,a half-helix or a loop in the third domain is coordinated by the C-terminal region of the opposite ***,we present the structures of OsHKT1;5 salt-tolerant and salt-sensitive variants,a key quantitative trait locus associated with salt *** salt-tolerant variant of OsHKT1;5 exhibits enhanced Na^(+)transport capability and displays a more flexible *** findings shed light on the molecular basis of rice HKTs and provide insights into their role in salt tolerance.

关键词： HKT salt-tolerant structure

Used car price prediction based on XGBoost and retention rate

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The Journal of China Universities of Posts and Telecommunications 2024年第3期31卷 72-79页

作者： Shen yutian Chen Jian Dai Min Zhang Sirui Xu Jing Wang Qing College of Mechanical Engineering Yangzhou UniversityYangzhou 225127China College of Economics and Management Southeast University Chengxian CollegeNanjing 210088China Shandong Shuncheng Automobile Trade Co. LtdJinan 250000China

In order to improve the accuracy of used car price prediction,a machine learning prediction model based on the retention rate is proposed in this ***,a random forest algorithm is used to filter the variables in the *** main characteristic variables that affect used car prices,such as new car price,service time,mileage and so on,are filtered ***,the linear regression classification method is introduced to classify the test data into high and low retention rate *** that,the extreme gradient boosting(XGBoost)regression model is built for the two datasets *** prediction results show that the comprehensive evaluation index of the proposed model is 0.548,which is significantly improved compared to 0.488 of the original XGBoost ***,compared with other representative machine learning algorithms,this model shows certain advantages in terms of mean absolute percentage error(MAPE),5%accuracy rate and comprehensive evaluation *** a result,the retention rate-based machine learning model established in this paper has significant advantages in terms of the accuracy of used car price prediction.

关键词： random forest data dimensionality reduction extreme gradient boosting(XGBoost) retention rate price prediction

Theory and application of stability for stochastic reaction diffusion systems

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Science in China(Series F) 2008年第2期51卷 158-170页

作者： LUO Qi DENG FeiQi MAO XueRong BAO JunDong ZHANG yutian College of Information and Control Nanjing University of Information Science & Technology Nanjing 210044 China College of Automation South China University of Technology Guangzhou 410640 China Department of Statistics and Modelling Science University of-Strathc/yde Glasgow G1 IXH Scotland UK Coilege of Mathematics Science Inner Mongolia Normal'University Huhhot 010000 China College of Mathematics and Physics Nanjing University of Information Science & Technology Nanjing 210044 China

So far, the Lyapunov direct method is still the most effective technique in the study of stability for ordinary differential equations and stochastic differential equations. Due to the shortage of the corresponding It6 formula, this useful method has not been popularized in stochastic partial differential equations. The aim of this work is to try to extend the Lyapunov direct method to the It6 stochastic reaction diffusion systems and to establish the corresponding Lyapunov stability theory, including stability in probablity, asymptotic stability in probablity, and exponential stability in mean square. As the application of the obtained theorems, this paper addresses the stability of the Hopfield neural network and points out that the main results ob- tained by Holden helge and Liao Xiaoxin et al. can be all regarded as the corollaries of the theorems presented in this paper.

关键词： stochastic reaction diffusion system stability in probability asymptotic stability in probability exponentialstability in mean square

Acupuncture on intrauterine growth restriction associated brain injury:case study including use of magnetic resonance imaging

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Journal of Traditional Chinese Medicine 2023年第3期43卷 602-605页

作者： XIN Zhixiong LI Jiyuan XU Yanni LING Jing JIANG Min YU yutian Department of Pediatrics People's Hospital of Sanshui DistrictFoshan 528000China Department of MRI Beijing Shijitan HospitalCapital Medical UniversityBeijing 100038China Ninth School of Clinical Medicine Peking UniversityBeijing 100038China Foshan Minfound Medical Imaging Diagnostic Center Foshan 528000China Department of Gynecology Shenzhen Traditional Chinese Medicine HospitalShenzhen 518033China Acupuncture Department Beijing Shijitan HospitalCapital Medical UniversityBeijing 100038China

Brain injury due to intrauterine growth restriction(IUGR) is a thorny clinical problem that often leads to permanent neurological deficits such as cerebral *** practical therapies can treat an IUGR-associated brain *** employed acupuncture to treat a 6-month-old male patient with severe hypoxic-ischemic encephalopathy(HIE) due to IUGR,as confirmed by magnetic resonance imaging(MRI).Three courses of acupuncture treatment significantly improved some of the patient’s clinical characteristics,such as his insensitive responsiveness and motor deficits,with remarkably reversed HIE features on MRI at 1-year of *** case suggests that acupuncture is a potential treatment option for an IUGRassociated brain injury and warrants further investigation.

关键词： acupuncture fetal growth retardation brain injuries hypoxia-ischemia brain magnetic resonance imaging neuronal plasticity