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Nano-micro Letters 2025年第3期17卷 87-101页

作者： Kaibiao xi Jianzhe Guo mupeng Zheng mankang Zhu Yudong Hou Key Laboratory of Advanced Functional materials Ministry of EducationCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124People’s Republic of China

High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless ***,simultaneously excellent performances,including high figure of merit(FOm),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported ***,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese *** to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOm_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese *** HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.

关键词： Lead-free piezoceramic Defect engineering Dopants modulation High-temperature Piezoelectric energy harvester

Deciphering Water Oxidation Catalysts:The Dominant Role of Surface Chemistry over Reconstruction Degree in Activity Promotion

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Nano-micro Letters 2025年第3期17卷 340-354页

作者： Li An Jianyi Li Yuanmiao Sun Jiamin Zhu Justin Zhu Yeow Seow Hong Zhang Nan Zhang Pinxian xi * Zhichuan JXu Chun‑Hua Yan State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu ProvinceFrontiers Science Center for Rare IsotopesCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000People’s Republic of China School of materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Faculty of materials Science and Energy Engineering Institute of Technology for Carbon NeutralityShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055People’s Republic of China Key Laboratory of Electromagnetic materials and Devices National Center for International Research On Photoelectric and Energy MaterialsSchool of Materials and EnergyElectron Microscopy CenterYunnan UniversityKunming 650091People’s Republic of China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030People’s Republic of China Beijing National Laboratory for molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsPKU‑HKU Joint Laboratory in Rare Earth Materials and Bioinorganic ChemistryPeking UniversityBeijing 100871People’s Republic of China

Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution *** surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity ***,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is *** substituting Fe content influences both current change tendency and surface reconstruction ***_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)*** reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based ***,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term ***,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction *** effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface *** finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.

关键词： Oxygen evolution reaction Perovskite oxides Doping Activation and reconstruction

Deliberate design of mOF-based pre-catalyst rationalizing the structural reconstruction toward efficient oxygen evolution reaction

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Science China Chemistry 2025年

作者： Yunhui Chen meng Tian Zhongqi Zhang Guangzhao Wang Yan Guo Jing Wu Dawei Qi Zhenhua Yan xiangyu Liu xi Liu State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering College of Chemistry and Chemical EngineeringNingxia University Key Laboratory of Extraordinary Bond Engineering and Advanced materials Technology of Chongqing School of Electronic Information Engineering Yangtze Normal University Frontiers Science Center for New Organic matter Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) State Key Laboratory of Advanced Chemical Power Sources College of Chemistry Nankai University School of Chemistry and Chemical Engineering In-situ Center for Physical Sciences Frontiers Science Center for Transformative Molecules Shanghai Jiao Tong University

metal-organic frameworks （mOFs）,that have emerged as promising electrocatalysts in oxygen evolution reaction （OER）,usually undergo structural reconstruction to form metal hydroxides as active ***,it remains a great challenge to design and synthesize ideal mOF-based pre-catalysts for properly cognizing and utilizing the reconstruction process toward efficient OER ***,the well-defined mOF-808 is post-modified by 2-hydroxyphosphonoacetic acid （HPAA） to form a micro-adsorber that enables to capture of metal ions ***3+and Ni2+ions are synergistically anchored into the microadsorber,developing a Fe/Ni-containing pre-catalyst that can be dynamically electrooxidized to be an active and stable dual-site electrocatalyst denoted by R-mOF-HPAA@FeNi with abundant metal *** a result,R-mOF-HPAA@FeNi exhibits an excellent OER performance with a low overpotential of 272 mV and Tafel slope of 35.9 m V dec-1,as well as long-term stability over 300 h at 10 m A *** and theoretical calculations suggest the resulting catalyst mainly follows a lattice oxygen mechanism （LOm） of dual-metal-site mechanism （DmSm）.Owing to the chelating role of HPAA,the post-synthesized mOF-HPAA behaves as a trap to uniformly and firmly adhere Fe3+and Ni2+ions,leading to a functionalized mOF-based pre-catalyst which can be structurally evolved into atomic level-distributed OER electrocatalysts.

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Performance enhancement of triboelectric nanogenerator based on BaTiO3-incorporated PVDF-HFP nanofibers for self-powered wearable sensors

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Science China Technological Sciences 2025年第1期 266-273页

作者： Tianjie DENG xi ZHANG Zhuanqing YANG Gang xiANG College of Physics Sichuan University

The triboelectric nanogenerators（TENGs） based on polyvinylidene fluoride（PVDF） have attracted significant attention due to their high energy conversion efficiency and strong flexibility. Indeed, the TENGs with higher electrical performance and stronger mechanical robustness are more desirable. In this context, we design and fabricate TENGs based on nanofiber（NF） layer of Poly（vinylidene fluoridehexafluoropropylene）(PVDF-HFP), a copolymer of PVDF with better mechanical properties, in which the enhancement of dielectric constant and specific surface area is achieved by incorporation of BaTiO3into PVDF-HFP NFs using electrospinning. The results show that the TENGs demonstrates superior electrical performance. The optimized TENG exhibits an open-circuit voltage（VOC） of 432 V, a short-circuit current（ISC） of 44.2 μA, and a maximum power density（Pd） of 2.25 W/m2. Practical applications of the optimized TENG are also demonstrated, including its use as power source, cylindrical rotating energy harvester and self-powered wearable sensor. The findings give insights into the fabrication, performance and application of the TENGs based on BaTiO3-incorporated PVDF-HFP NFs, offering promising solutions for energy harvesting and diverse applications.

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Infrared radiation simulation of exhaust system by coupling FVm with narrow band k-distribution

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航空动力学报 2012年第1期27卷 25-32页

作者： ZHU xi-juan Eriqitai LI xi-xi WANG Qiang School of Jet Propulsion Beijing University of Aeronautics and AstronauticsBeijing 100191China

A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting *** final infrared signature had considered the atmosphere effect,and the simulation values were favorably consistent with testing *** results indicate that the relative errors considering the effect of atmosphere compared with that of the contrary condition reduce by 31%,it shows that when simulating the infrared radiation of the target which is received by the infrared detectors,even the calculation band is in atmospheric windows 3～5 μm,the effect of atmospheric transmission on infrared signature of the target should not be neglected.

关键词： exhaust system infrared radiation(IR) finite volume method(FVm) narrow band k-distribution atmospheric transmission

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Smooth quadrotor trajectory generation for tracking a moving target in cluttered environments

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Science China(Information Sciences) 2021年第7期64卷 132-147页

作者： Lele xi Zhihong PENG Lei JIAO Ben m.CHEN School of Automation Beijing Institute of Technology State Key Laboratory of Intelligent Control and Decision of Complex System Peng Cheng Laboratory Department of mechanical and Automation Engineering The Chinese University of Hong Kong

In this paper, we present a trajectory generation method of a quadrotor, based on the optimal smoothing B-spline, for tracking a moving target with consideration of relative tracking pattern or limited field of view of the onboard sensor in cluttered environments. Compared to existing methods, safe flying zone,vehicle physical limits, and smoothness are fully considered to guarantee flight safety, kinodynamic feasibility, and tracking performance. To tackle the cluttered environments, a parallel particle swarm optimization algorithm is applied to find the feasible waypoints that the generated trajectory should be as close to as possible, with consideration of the target’s future state as well as obstacles to trade off the tracking performance and flight safety. Then, a sequential motion planning method, considering the above constraints, is applied and embedded into a cost function for solving the problem of robust tracking trajectory generation for the quadrotor via a convex optimization approach. The feasibility and effectiveness of the proposed method are verified by numerical simulations.

关键词： quadrotor target tracking trajectory generation B-spline convex optimization

Effect of heat-source geometry on distribution and deposition of particulates in a ventilated chamber

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Particuology 2018年第1期16卷 174-184页

作者： xi Chen School of Civil Engineering and Architecture Henan University of Technology Zhengzhou 450001 Henan China Key Laboratory of Heating and Air Conditioning The Education Department of Henan Province Zhengzhou 450007 Henan China

To investigate the effect of near-wall heat-source shape on particulate motion, the particulate distribu~ tion and deposition in a ventilated chamber with different heat-source configurations were numerically modeled. Using the discrete random walk model of the Lagrangian method, the trajectories of 3200 mono-disperse particulates ranging from 1 to 10 μm with a density of 1400 kg/m3 were tracked. Airflow pattern, temperature fields, the distribution of particulate concentrations, and deposition patterns are calculated and presented. The results show that the shape of a near-wall heat source has an influence on the airflow as well as the temperature field in the chamber and hence affects the particulate distribution and deposition.

关键词： Particle deposition Particle distribution Near-wall heat source Computational fluid dynamicsLagrangian method

基于点云语义分割的猕猴桃冠层叶密度测量方法

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农机化研究 2025年第2期47卷 27-35页

作者：韩皓名石复习席新明西北农林科技大学机械与电子工程学院陕西杨凌712100

提出了一种基于LiDAR的猕猴桃果园叶密度测量方法,旨在为猕猴桃果园冠层喷药提供更精确的指导。首先,使用激光雷达扫描10个密度不同的猕猴桃冠层建立点云数据集,利用RandLA-Net神经网络模型并通过6折交叉验证的方法对猕猴桃冠层的树叶... 详细信息

提出了一种基于LiDAR的猕猴桃果园叶密度测量方法,旨在为猕猴桃果园冠层喷药提供更精确的指导。首先,使用激光雷达扫描10个密度不同的猕猴桃冠层建立点云数据集,利用RandLA-Net神经网络模型并通过6折交叉验证的方法对猕猴桃冠层的树叶、树枝和T型架点云进行语义分割;然后,计算仅包含树叶信息的冠层点云表面积,通过与人工落叶后的实测冠层叶属性(叶面积、叶片数)进行回归分析比较,得到冠层叶点云表面积与真实冠层叶属性的关系;最后,将3 m×3 m的猕猴桃冠层区域划分为400个225 cm^(2)的小网格区域,用以生成冠层叶密度图。结果表明:RandLA-Net网络模型能够有效地对猕猴桃冠层的树枝、树叶与T型架点云进行分割,模型平均总体精度OA达到92%以上,平均交并比mIoU为81.4%,冠层实测叶面积与冠层叶点云表面积的回归分析中获得了较高的相关性R=0.78,回归方程为y=1.491x+8315。对于每个猕猴桃冠层点云数据,通过Alpha-shape算法计算网格区域的冠层体积和预测网格真实叶面积的方法生成冠层叶密度图。所开发的基于点云语义分割的猕猴桃冠层叶密度测量方法,各项指标均符合预期要求,可以为果园冠层喷药提供更精准的指导。

关键词：猕猴桃园冠层叶密度点云语义分割深度学习精准喷雾

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Frobenius bimodules and flat-dominant dimensions

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Science China mathematics 2021年第1期64卷 33-44页

作者： Changchang xi School of mathematical Sciences Capital Normal UniversityBeijing100048China

We establish relations between Frobenius parts and between flat-dominant dimensions of algebras linked by Frobenius *** is motivated by the Nakayama conjecture and an approach of martinezVilla to the Auslander-Reiten conjecture on stable *** show that the Frobenius parts of Frobenius extensions are again Frobenius ***,let A and B be finite-dimensional algebras over a field k,and let domdim(_AX)stand for the dominant dimension of an A-module ***_Bm_A is a Frobenius bimodule,then domdim(A)domdim(_Bm)and domdim(B)domdim(_AHom_B(m,B)).In particular,if B■A is a left-split(or right-split)Frobenius extension,then domdim(A)=domdim(B).These results are applied to calculate flat-dominant dimensions of a number of algebras:shew group algebras,stably equivalent algebras,trivial extensions and markov *** also prove that the universal(quantised)enveloping algebras of semisimple Lie algebras are QF-3 rings in the sense of morita.

关键词： dominant dimension extension of algebras Frobenius bimodule Frobenius part universal enveloping algebra

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Descriptors-based machine-learning prediction of cetane number using quantitative structure–property relationship

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Energy and AI

Energy and AI 2024年第3期17卷 168-178页

作者： Rodolfo S.m.Freitas xi Jiang School of Engineering and materials Science Queen Mary University of LondonMile End RoadLondonE14NSUK

The physicochemical properties of liquid alternative fuels are important but difficult to measure/predict, especially when complex surrogate fuels are concerned. In the present work, machine learning is used to develop quantitative structure–property relationship models. The fuel chemical structure is represented by molecular descriptors, allowing the linking of important features of the fuel composition and key properties of fuel utilization. Feature selection is employed to select the most relevant features that describe the chemical structure of the fuel and several machine learning algorithms are tested to construct interpretable models. The effectiveness of the methodology is demonstrated through the development of accurate and interpretable predictive models for cetane numbers, with a focus on understanding the link between molecular structure and fuel properties. In this context, matrix-based descriptors and descriptors related to the number of atoms in the molecule are directly linked with the cetane number of hydrocarbons. Furthermore, the results showed that molecular connectivity indices play a role in the cetane number for aromatic molecules. Also, the methodology is extended to predict the cetane number of ester and ether molecules, leveraging the design of alternative fuels towards fully sustainable fuel utilization.

关键词： Chemical descriptors Quantitative structure-property relationship machine learning Cetane number Fuel design