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Remote sensing of air pollution incorporating integrated-path differential-absorption and coherent-Doppler lidar

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Defence Technology（防务技术） 2024年第1期31卷 594-601页

作者： Ze-hou Yang Yong chen Chun-li chen Yong-ke Zhang ji-hui Dong tao Peng Xiao-feng Li Ding-fu Zhou School of Physics Beijing Institute of TechnologyBeijing 100081China Southwest Institute of Technical Physics Chengdu 610041SichuanChina School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China

An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and *** system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber *** combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric *** static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 *** experiments is conducted with the *** of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 *** test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.

关键词： Differential absorption LIDAR Coherent Doppler lidar Remoting sensing Atmospheric pollution

Hydrogel bioadhesives harnessing nanoscale phase separation for Achilles tendon repairing

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Nano Research 2024年第2期17卷 778-787页

作者： Jun Zhang Xingmei chen jingseng Lin Pei Zhang Iek Man Lei Yue tao jiajun Zhang Tian Luo ji Liu Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China Research and Innovation Center SKG Health TechnologyShenzhen 518000China SAFE(Shenzhen)Medical Technology Company Limited Shenzhen 518000China Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems Department of Mechanical and Energy EngineeringSouthern University of Science and TechnologyShenzhen 518055China Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities Southern University of Science and TechnologyShenzhen 518055China

Repairing Achilles tendon has emerged as a long-standing challenge in the orthopaedic *** suture is the gold standard for re-attaching and repairing the fractured Achilles tendons in clinical surgeries,it is still subjected to numerous adverse side-effects,including chronic inflammatory,tendon tissue re-rupture,scar formation,and post-surgical peritendinous *** this work,we develop a class of hydrogel bioadhesives with tailored nanoscale phase separation for Achilles tendon *** address the existing limitations of sutures,our hydrogel bioadhesives encompass three core functionalities:(i)instant and tough adhesion to Achilles tendon tissues,(ii)extraordinary long-term adhesion robustness under wet and dynamic in vivo conditions,and(iii)anti-postsurgical peritendinous *** our hydrogel bioadhesives with sutures,such kind of integrated approach enables a conformable yet robust biointerface with the tendon tissues,and prevents the fibroblast migration and formation of connective tissues,thus facilitating the tendon *** hydrogel bioadhesives reported here open up new opportunities for the repairing of fractured Achilles tendons in diverse and complicated clinical scenarios.

关键词： hydrogels phase separation bioadhesion robustness tendon repairing

Exploring Long-Memory Process in the Prediction of Interval-Valued Financial Time Series and Its Application

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Journal of Systems Science & Complexity 2024年第2期37卷 759-775页

作者： SHEN Tingting tao Zhifu chen Huayou School of Economics Anhui UniversityHefei 230601China Center for Financial and Statistical Research Anhui UniversityHefei 230061China Stony Brook Institute at Anhui University Anhui UniversityHefei 230601China Center for Applied Mathematics Anhui UniversityHefei 230601China

Long-memory process has been widely studied in classical financial time series analysis,which has merely been reported in the field of interval-valued financial time *** aim of this paper is to explore long-memory process in the prediction of interval-valued time series(IvTS).To model the long-memory process,two novel interval-valued time series prediction models named as interval-valued vector autoregressive fractionally integrated moving average(IV-VARFIMA)and ARFIMAX-FIGARCH were *** the developed long-memory pattern,both of the short term and long-term influences contained in IvTS can be *** an application of the proposed models,interval-valued form of WTI crude oil futures price series is *** to current IvTS prediction models,IV-VARFIMA and ARFIMAX-FIGARCH can provide better in-sample and out-of-sample forecasts.

关键词： ARFIMAX-FIGARCH interval-valued time series IV-VARFIMA long-memory process WTI crude oil futures price

Nuclearity and Finite-Representability in the System of Completely Integral Mapping Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1197-1214页

作者： Zhe DONG ji cheng tao Ya Fei ZHAO Department of Mathematics Zhejiang UniversityHangzhou 310027P.R.China Department of Mathematics China Jiliang UniversityHangzhou 310018P.R.China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023P.R.China

In this paper,we investigate local properties in the system of completely integral mapping *** introduce notions of injectivity,local reflexivity,exactness,nuclearity,finite-represent ability and WEP in the system of completely integral mapping *** we obtain that any finite-dimensional operator space is injective in the system of completely integral mapping *** we prove that C is the unique nuclear operator space and the unique exact operator space in this *** also show that C is the unique operator space which is finitely representable in{T_(n)}n∈Nin this *** corollaries,Kirchberg’s conjecture and QWEP conjecture in the system of completely integral mapping spaces are false.

关键词： Completely integral mapping space injectivity exactness nuclearity finite-representability WEP

Nitsche-XFEM for a time fractional diffusion interface problem

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Science China Mathematics 2024年第3期67卷 665-682页

作者： tao Wang Yanping chen China Nuclear Power Technology Research Institute Co.Ltd. Shenzhen 518028China School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China

In this paper, we propose a space-time finite element method for a time fractional diffusion interface problem. This method uses the low-order discontinuous Galerkin(DG) method and the Nitsche extended finite element method(Nitsche-XFEM) for temporal and spatial discretization, respectively. Sharp pointwise-in-time error estimates in graded temporal grids are derived, without any smoothness assumptions on the ***, three numerical examples are provided to verify the theoretical results.

关键词： fractional diffusion interface discontinuous Galerkin Nitsche-XFEM error estimates

Selective control of secondary alcohols upgrading using Ir-catalyzed cross-coupling strategy

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Science China Chemistry 2024年第3期67卷 914-921页

作者： Siqi Yang Zeye Lu jiale ji Qingshu Zheng tao Tu Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of ChemistryFudan UniversityShanghai 200438China Frontiers Science Center for Transformative Molecules School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

The selective coupling of alcohols is a fascinating yet challenging approach for upgrading alcohols. Herein, we accomplished the controlled production of β-disubstituted ketones or upgraded secondary alcohols via the Ir-catalyzed cross-coupling of secondary alcohols in excellent yields with broad substrate scopes. This selective control was achieved by using an in-situ generated monoNHC-Ir or a tris-NHC-Ir complex as the catalysts, respectively. Mechanistic studies revealed that the delicate balance between dehydrogenation and hydrogenation abilities of these bifunctional catalysts is crucial for achieving different selectivity. The tris-NHC-Ir complex effectively facilitated dehydrogenation of alcohols and hydrogenation of intermediates, leading to the desired upgraded secondary alcohols. Conversely, the high dehydrogenation ability of the mono-NHC-Ir complex promoted the conversion of formed secondary alcohols back to ketones.

关键词： cross-coupling hydrogen-borrowing NHC-Ir complexes selectivity control upgrading of alcohols

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Data-Driven Active Disturbance Rejection Control of Plant-Protection Unmanned Ground Vehicle Prototype:A Fuzzy Indirect Iterative Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1892-1894页

作者： tao chen Ruiyuan Zhao jian chen Zichao Zhang the College of Engineering China Agricultural University the Key Laboratory of Smart Agricultural Technology in Tropical South China Ministry of Agriculture and Rural Affairs

Dear Editor,This letter proposes a fuzzy indirect iterative learning (FIIL) active disturbance rejection control (ADRC) scheme to address the impact of uncertain factors of plant-protection unmanned ground vehicle(UGV), in which ADRC is a data-driven model-free control algorithm that only relies on the input and output data of the *** on the established nonlinear time-varying dynamic model including dynamic load (medicine box), the FIIL technology is adopted to turn the bandwidth and control channel gain online, in which the fuzzy logic system is used to update the gain parameters of iterative learning in real time. Simulation and experiment show the FIIL-ADRC scheme has better control performance.

关键词： Dynamic loads

Basic Survey Scheduling for the Wide Field Survey Telescope(WFST)

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Research in Astronomy and Astrophysics 2024年第1期24卷 59-69页

作者： Yan-Peng chen ji-An jiang Wen-tao Luo Xian-Zhong Zheng Min Fang Chao Yang Yuan-Yu Hong Zong-Fei Lü Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Department of Astronomy University of Science and Technology of ChinaHefei 230026China National Astronomical Observatory of Japan National Institutes of Natural Sciences2-21-1 OsawaMitakaTokyo 181-8588Japan Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230026China

Aiming at improving the survey efficiency of the Wide Field Survey Telescope, we have developed a basic scheduling strategy that takes into account the telescope characteristics, observing conditions, and weather conditions at the Lenghu site. The sky area is divided into rectangular regions, referred to as “tiles,” with a size of2°. 577 × 2°. 634 slightly smaller than the focal area of the mosaic CCDs. These tiles are continuously filled in annulars parallel to the equator. The brightness of the sky background, which varies with the moon phase and distance from the moon, plays a significant role in determining the accessible survey fields. Approximately 50connected tiles are grouped into one block for observation. To optimize the survey schedule, we perform simulations by taking into account the length of exposures, data readout, telescope slewing, and all relevant observing conditions. We utilize the Greedy Algorithm for scheduling optimization. Additionally, we propose a dedicated dithering pattern to cover the gaps between CCDs and the four corners of the mosaic CCD array, which are located outside of the 3° field of view. This dithering pattern helps to achieve relatively uniform exposure maps for the final survey outputs.

关键词： telescopes surveys Moon

In-situ powder mixing for laser-based directed energy deposition of functionally graded materials

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Advances in Manufacturing 2024年第1期12卷 150-166页

作者： ji-Peng chen Shou-Chun Xie He Huang School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037People’s Republic of China Nanjing Huirui Photoelectric Technology Co. LtdNanjing211121People’s Republic of China

The mixing of powders is a highly relevant field under additive manufacturing,however,it has attracted limited interest to *** in-situ mixing of various powders remains a significant *** paper proposes a new method utilizing a static mixer for the in-situ mixing of multiple powders through the laser-based directed energy deposition(DED)of functionally graded ***,a powder-mixing experimental platform was established;WC and 316L powders were selected for the mixing ***,scanning electron microscopy,energy dispersive spectroscopy,and image processing were used to visually evaluate the homogeneity and proportion of the in-situ mixed ***,powder-mixing simulations were conducted to determine the powder-mixing *** the simulations,a powder carrier gas flow field and particle mixing were ***,a WC/316L metal matrix composite sample was produced using laser-based DED to verify the application potential of the static *** was found that the static mixer could adjust the powder ratio online,and a response time of 1–2 s should be considered when adjusting the ratio of the mixed powder.A feasible approach for in-situ powder mixing for laser-based DED was demonstrated and investigated,creating the basis for functionally graded materials.

关键词： Laser Deposition Static mixer Powder mixing Functionally graded materials