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Charge collection narrowing mechanism in electronic-grade-diamond photodetectors

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Opto-Electronic Advances 2024年第6期7卷 1-3页

作者： xiaoping Ouyang State Key Laboratory of Intense Pulsed Radiation Simulation and Effect and Radiation Detection Research Center Northwest Institute of Nuclear TechnologyXi’an 710024China

Recently,an extreme narrowband spectral response of only 8 nm in electronic-grade diamond-based photodetectors has been observed by Zheng Wei and his colleagues from Sun Yat-sen University for the first time.A charge collection narrowing mechanism assisted by free exciton radiative recombination is proposed,which well reveals the characteristic spectral response of diamond.

关键词： mechanism electronic extreme

Insights into the mechanism of multiple Cu-doped Co Fe_(2)O_(4)nanocatalyst activated peroxymonosulfate for efficient degradation of Rhodamine B

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Journal of Environmental Sciences 2024年第3期137卷 382-394页

作者： Yuanmin Mo xiaoping Zhang School of Environment&Energy South China University of TechnologyGuangzhou Higher Education Mega CentreGuangzhou 510006China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education Guangzhou 510006China Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling Guangzhou 510006China Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal Guangzhou 510006China

The multiple metal catalyst as a promising nanomaterial has shown excellent activity in the peroxymonosulfate(PMS)activation for pollutant ***,the role of special sites and in-depth understanding of the PMS activation mechanism are not fully *** this study,a Cu-doped CoFe_(2)O_(4)nanocatalyst(0.5CCF)was synthesized by a sol-gel and calcination method,and used for PMS activation to remove Rhodamine B(RhB).The results showed that the Cu doping obviously enhanced the catalytic performance of CoFe_(2)O_(4),with 99.70%of RhB removed by 0.5CCF while 74.91.in the CoFe_(2)O_(4)within 1. *** on the X-ray photoelectron spectroscopy and electrochemical analysis,this could be ascribed to the more low valence of Co and Fe species generated on the 0.5CCF and faster electron transfers occurred in the 0.5CCF due to the Cu *** addition,Cu doping could provide more reaction sites for the 0.5CCF to activate PMS for RhB *** metal species and the surface hydroxyl were the reaction sites of PMS activation,and the surface hydroxyl played an important role in surface-bound reactive species *** the PMS activation,the Cu not only activated PMS to produce reactive oxygen species(ROS),but also regenerated Co^(2+)and Fe^(2+)to accelerate the PMS *** non-radical of ^(1.O_(2)was the main ROS with a 99.35%of contribution rate,and the SO_(5)^(·–)self-reaction was its major *** study provides a new insight to enhance the PMS activation performance of multiple metal catalysts by Cu doping in wastewater treatment.

关键词： Cu-doped CoFe_(2)O_(4)nanocatalyst PMS activation Mechanism Rhodamine B removal

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基于有监督哈希的肺结节CT图像检索

计算机应用研究 2017年第9期34卷 2838-2842页

作者：潘玲杜晓平赵涓涓太原理工大学计算机科学与技术学院山西晋中030600 山西省煤炭中心医院PET-CT中心太原030006

针对传统方法在面对大量肺部数据时检索效率不高的问题,提出了一种基于有监督哈希的肺结节CT图像检索方法。通过图像预处理建立肺结节图像库,并从灰度、形态、纹理方面提取图像多特征;利用监督信息构造哈希函数,将多特征映射为低维哈希... 详细信息

针对传统方法在面对大量肺部数据时检索效率不高的问题,提出了一种基于有监督哈希的肺结节CT图像检索方法。通过图像预处理建立肺结节图像库,并从灰度、形态、纹理方面提取图像多特征;利用监督信息构造哈希函数,将多特征映射为低维哈希码;根据设计的自适应权重计算图像相似度,并返回相似的肺结节图像。实验结果表明,该方法能有效地实现肺结节CT图像的快速检索,对查询病灶的良恶性分类精度达到了89.45%。

关键词：肺结节图像检索多特征提取有监督哈希自适应权重分类

Analysis of a class of globally divergence-free HDG methods for stationary Navier-Stokes equations

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Science China Mathematics 2024年第5期67卷 1133-1158页

作者： Gang Chen xiaoping Xie School of Mathematics Sichuan University Chengdu 610064China

In this paper,we analyze a class of globally divergence-free(and therefore pressure-robust)hybridizable discontinuous Galerkin(HDG)finite element methods for stationary Navier-Stokes *** methods use the P_(k)/P_(k-1.(k≥1.discontinuous finite element combination for the velocity and pressure approximations in the interior of elements,piecewise Pm(m=k,k-1.for the velocity gradient approximation in the interior of elements,and piecewise P_(k)/P_(k) for the trace approximations of the velocity and pressure on the inter-element *** show that the uniqueness condition for the discrete solution is guaranteed by that for the continuous solution together with a sufficiently small mesh *** on the derived discrete HDG Sobolev embedding properties,optimal error estimates are *** experiments are performed to verify the theoretical analysis.

关键词： Navier-Stokes equations HDG methods divergence-free uniqueness condition error estimates

A Comparison of Four Neural Networks Algorithms on Locomotion Intention Recognition of Lower Limb Exoskeleton Based on Multi-source Information

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Journal of Bionic Engineering 2024年第1期21卷 224-235页

作者： Duojin Wang xiaoping Gu Hongliu Yu Institute of Rehabilitation Engineering and Technology University of Shanghai for Science and Technology516 Jungong RoadShanghai 200093China Shanghai Engineering Research Center of Assistive Devices 516 Jungong RoadShanghai 200093China

Lower Limb Exoskeletons(LLEs)are receiving increasing attention for supporting activities of daily *** such active systems,an intelligent controller may be *** this paper,we proposed a locomotion intention recognition system based on time series data sets derived from human motion *** of input data and Deep Learning(DL)algorithms,this framework enables the detection and prediction of users’movement *** makes it possible to predict the detection of locomotion modes,allowing the LLEs to provide smooth and seamless *** pre-processed eight subjects were used as input to classify four scenes:Standing/Walking on Level Ground(S/WOLG),Up the Stairs(US),Down the Stairs(DS),and Walking on Grass(WOG).The result showed that the ResNet performed optimally compared to four algorithms(CNN,CNN-LSTM,ResNet,and ResNet-Att)with an approximate evaluation indicator of 1.0%.It is expected that the proposed locomotion intention system will significantly improve the safety and the effectiveness of LLE due to its high accuracy and predictive performance.

关键词： Lower limb exoskeletons(LLEs) Locomotion intention ResNet Multi-source

Mechanism of microarc oxidation on AZ91. Mg alloy induced byβ-Mg_(1.)Al_(1.) phase

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 712-724页

作者： Dajun Zhai xiaoping Li Jun Shen College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(1.)Al_(1.)phase in AZ91. Mg *** kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(1.)Al_(1.)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/*** characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic *** was found that the coarseα-Mg grains in extruded AZ91. Mg alloy were refined by FSP,and theβ-Mg_(1.)Al_(1.)phase with reticular structure was broken and *** nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(1.)Al_(1.)phase in *** effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge *** MAO coating on Zr-FSP sample had good wettability and corrosion ***,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

关键词： AZ91. Mg alloy microarc oxidation friction stir processing ZrO_(2) TiO_(2) β-Mg_(1.)Al_(1.)

Coupled Surface Process and Orographic Precipitation Model for the Landscape Evolution of the Himalayas

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Journal of Earth Science 2024年第3期35卷 1063-1068页

作者： Yuqiang Li xiaoping Yuan Hubei Key Laboratory of Critical Zone Evolution School of Earth SciencesChina University of GeosciencesWuhan 430074China

0 INTRODUCTION The landscape evolution of mountain belts links rock uplift caused by tectonic deformation in the lithosphere to fluvial erosion and deposition driven by climatic precipitation in the *** Himalayas,one of the most typical mountain belts in the world,are undergoing the strong collision of the Indian and Eurasian plates and the strong South Asian monsoon precipitation(Figure 1.).It is a natural laboratory to research the evolution mechanisms of orogenic growth involving tectonic and climatic *** addition,it is a good prototype to advance and verify many research methods in multiple *** Indian-Eurasian collision initiated since the Early Paleogene(ca.50 Ma)based on geological,stratigraphic,and palaeomagnetic records(Ding et al.,2022;van Hinsbergen et al.,201.),causing an early slow topographic change in the Himalayas until the Neogene(ca.23 Ma)(Ding et al.,2022).

关键词： Eurasian climatic tectonic

Deep-reinforcement-learning-based UAV autonomous navigation and collision avoidance in unknown environments

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Chinese Journal of Aeronautics 2024年第3期37卷 237-257页

作者： Fei WANG xiaoping ZHU Zhou ZHOU Yang TANG School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

In some military application scenarios,Unmanned Aerial Vehicles(UAVs)need to perform missions with the assistance of on-board cameras when radar is not available and communication is interrupted,which brings challenges for UAV autonomous navigation and collision *** this paper,an improved deep-reinforcement-learning algorithm,Deep Q-Network with a Faster R-CNN model and a Data Deposit Mechanism(FRDDM-DQN),is proposed.A Faster R-CNN model(FR)is introduced and optimized to obtain the ability to extract obstacle information from images,and a new replay memory Data Deposit Mechanism(DDM)is designed to train an agent with a better *** training,a two-part training approach is used to reduce the time spent on training as well as retraining when the scenario *** order to verify the performance of the proposed method,a series of experiments,including training experiments,test experiments,and typical episodes experiments,is conducted in a 3D simulation *** results show that the agent trained by the proposed FRDDM-DQN has the ability to navigate autonomously and avoid collisions,and performs better compared to the FRDQN,FR-DDQN,FR-Dueling DQN,YOLO-based YDDM-DQN,and original FR outputbased FR-ODQN.

关键词： Faster R-CNN model Replay memory Data Deposit Mechanism(DDM) Two-part training approach Image-based Autonomous Navigation and Collision Avoidance(ANCA) Unmanned Aerial Vehicle(UAV)

Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate

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International Journal of Mining Science and Technology 2024年第2期34卷 149-165页

作者： xiaoping Zhou Linyuan Han Jing Bi Yundong Shou School of Civil Engineering Wuhan UniversityWuhan 430072China College of Civil Engineering Guizhou UniversityGuiyang 550025China

High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing *** effectively extract shale gas,it is important to understand the dynamic mechanical properties of *** experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this *** dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are *** results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate *** characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial ***,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of *** dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D *** numerical results are in good agreement with the experimental data.

关键词： Dynamic behaviors True triaxial compression High strain rates Dynamic failure mechanism PFC3D-FLAC3D coupled method