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Robust restoration of low-dose cerebral perfusion CT images using NCS-Unet

Nuclear Science and Techniques 2022年第3期33卷 62-76页

作者： Kai Chen Li-Bo Zhang Jia-Shun Liu Yuan Gao Zhan Wu Hai-Chen Zhu chang-ping du Xiao-Li Mai Chun-Feng Yang Yang Chen Southeast University Nanjing 210096China School of Cyber Science and Engineering Southeast UniversityNanjing 210096China Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of EducationNanjing 210096China Department of Radiology General Hospital of the Northern Theater of the Chinese People’s Liberation ArmyShenyang 110016China Laboratory of Image Science and Technology The School of Computer Science and EngineeringSoutheast UniversityNanjing 210096China Department of Radiology Nanjing Drum Tower HospitalThe Affiliated Hospital of Nanjing University Medical SchoolNanjing 210008China Jiangsu Key Laboratory of Molecular and Functional Imaging Department of RadiologyZhongda HospitalSoutheast UniversityNanjing 210009China Jiangsu Provincial Joint International Research Laboratory of Medical Information Processing School of Computer Science and EngineeringSoutheast UniversityNanjing 210096China

Cerebral perfusion computed tomography(PCT)is an important imaging modality for evaluating cerebrovascular diseases and stroke *** widespread public concern about the potential cancer risks and health hazards associated with cumulative radiation exposure in PCT imaging,considerable research has been conducted to reduce the radiation dose in X-ray-based brain perfusion *** the dose of X-rays causes severe noise and artifacts in PCT *** solve this problem,we propose a deep learning method called *** exceptional characteristics of non-subsampled contourlet transform(NSCT)and the Sobel filter are introduced into *** decomposes the convolved features into high-and low-frequency *** decomposed high-frequency component retains image edges,contrast imaging traces,and noise,whereas the low-frequency component retains the main image *** Sobel filter extracts the contours of the original image and the imaging traces caused by the contrast agent *** extracted information is added to NCS-Unet to improve its performance in noise reduction and artifact *** and quantitative analyses demonstrated that the proposed NCS-Unet can improve the quality of low-dose cone-beam CT perfusion reconstruction images and the accuracy of perfusion parameter calculations.

关键词： Cerebral perfusion CT Low-dose Image denoising Perfusion parameters

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A Galaxy Image Augmentation Method Based on Few-shot Learning and Generative Adversarial Networks

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Research in Astronomy and Astrophysics 2024年第3期24卷 180-193页

作者： Yiqi Yao Jinqu Zhang ping du Shuyu Dong School of Artificial Intelligence South China Normal UniversityFoshan 528225China School of Computer Science South China Normal UniversityGuangzhou 510631China Guangdong Construction Vocational Technology Institute Guangzhou 511500China

Galaxy morphology classifications based on machine learning are a typical technique to handle enormous amounts of astronomical observation data,but the key challenge is how to provide enough training data for the machine learning *** this article proposes an image data augmentation method that combines few-shot learning and generative adversarial *** Galaxy10 DECaLs data set is selected for the experiments with consistency,variance,and augmentation effects being *** popular networks,including AlexNet,VGG,and ResNet,are used as examples to study the effectiveness of different augmentation methods on galaxy morphology *** results show that the proposed method can generate galaxy images and can be used for expanding the classification model’s training *** to comparative studies,the best enhancement effect on model performance is obtained by generating a data set that is 0.5–1 time larger than the original data ***,different augmentation strategies have considerably varied effects on different types of ***-GAN achieved the best classification performance on the ResNet network for In-between Round Smooth Galaxies and Unbarred Loose Spiral Galaxies,with F1 Scores of 89.54%and 63.18%,*** comparison reveals that various data augmentation techniques have varied effects on different categories of galaxy morphology and machine learning ***,the best augmentation strategies for each galaxy category are suggested.

关键词： techniques image processing-galaxies structure-galaxies general

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Energy-efficient reconfigurable processor for QC-LDPC via adaptive coding-voltage-frequency tuning

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 72-84页

作者： chang Libo Hu Yiqing du Huimin Wang Jihe School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China School of Computer Science Northwestern Polytechnical UniversityXi'an 710072China

To apply a quasi-cyclic low density parity check(QC-LDPC)to different scenarios,a data-stream driven pipelined macro instruction set and a reconfigurable processor architecture are proposed for the typical QC-LDPC *** data-level parallelism is improved by instructions to dynamically configure the multi-core computing ***,an intelligent adjustment strategy based on a programmable wake-up controller(WuC)is designed so that the computing mode,operating voltage,and frequency of the QC-LDPC algorithm can be *** adjustment can improve the computing efficiency of the *** QC-LDPC processors are verified on the Xilinx ZCU102 field programmable gate array(FPGA)board and the computing efficiency is *** experimental results indicate that the QC-LDPC processor can support two encoding lengths of three typical QC-LDPC algorithms and 20 adaptive operating modes of operating voltage and *** maximum efficiency can reach up to 12.18 Gbit/(s·W),which is more flexible than existing state-of-the-art processors for QC-LDPC.

关键词： quasi-cyclic low density parity check(QC-LDPC) dynamic voltage and frequency scaling(DVFS) reconfigurable computing coarse-grained reconfigurable arrays(CGRAs)

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Hierarchical Task Planning for Power Line Flow Regulation

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 29-40页

作者： Chenxi Wang Youtian du Yanhao Huang Yuanlin chang Zihao Guo the Ministry of Education Key Lab for Intelligent Networks and Network Security Xi'an Jiaotong UniversityXi'an 713599China the State Key Laboratory of Power Grid Safety and Energy Conservation China Electric Power Research InstituteBeijing 100192China

The complexity and uncertainty in power systems cause great challenges to controlling power *** a popular data-driven technique,deep reinforcement learning(DRL)attracts attention in the control of power ***,DRL has some inherent drawbacks in terms of data efficiency and *** paper presents a novel hierarchical task planning(HTP)approach,bridging planning and DRL,to the task of power line flow ***,we introduce a threelevel task hierarchy to model the task and model the sequence of task units on each level as a task planning-Markov decision processes(TP-MDPs).Second,we model the task as a sequential decision-making problem and introduce a higher planner and a lower planner in HTP to handle different levels of task *** addition,we introduce a two-layer knowledge graph that can update dynamically during the planning procedure to assist *** results conducted on the IEEE 118-bus and IEEE 300-bus systems demonstrate our HTP approach outperforms proximal policy optimization,a state-of-the-art deep reinforcement learning(DRL)approach,improving efficiency by 26.16%and 6.86%on both systems.

关键词： Knowledge graph power line flow regulation reinforcement learning task planning

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Si/TiO2 carbon fiber core encapsulated in hierarchical multiple MXene@Co-MoS2 shells for constructing a free-standing anode of lithium storage

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Rare Metals 2024年第9期43卷 4222-4233页

作者： Xian-ping du Ying Huang Jia-ming Wang Zhen-he Feng Xu Sun MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical Engineering Northwestern Polytechnical University Shanghai Institute of Space Power-Sources Ningbo Institute of Northwestern Polytechnical University

Silicon-based（Si-based） materials offer more possibilities for generating new portable electronic devices due to their high specific capacities. However, their inferior electrical conductivity and volume expansion during cycling seriously limit their development. The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties. In this study, Si particles were confined in TiO2carbon fibers（TiO2CFs） via electrospinning, after which they were encapsulated with MXene and Co-MoS2（CMS） nanosheets to fabricate hierarchical ST-2@MXene@CMS films. TiO2CF, MXene and CMS were employed to establish a coherent conductive network with one-, two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material. TiO2CF, MXene and CMS acted precisely as multilayered buffers to ameliorate the volume change of Si particles during cycling. In addition, the CMS nanosheets were involved in lithium storage, contributing to the final electrochemical performance. Ultimately, the ST-2@MXene@CMS films served as free-standing electrodes, avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.

关键词： Co-MoS2 nanosheets Hierarchical structure Lithium-ion batteries MXene Si particles

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Effects of inorganic nutrients and environmental factors on the removal of n-propylbenzene and isopropylbenzene in seawater by cryptophytes Rhinomonas reticulata S6A

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Journal of Oceanology and Limnology 2024年第4期42卷 1200-1215页

作者： Jiali CUI Shuhao du Yumei LI Haiping LI ping ZHANG Fanping MENG Key Laboratory of Marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China

To effectively remove n-propylbenzene(n-PBZ)and isopropylbenzene(i-PBZ)leaked into seawater using Rhinomonas reticulata S6A(a newly isolated marine microalga),the effects of three inorganic nutrients and four environmental factors on their degradation were determined after 7 d of *** show that NaNO_(3) at 300 mg/L caused a higher removal efficiency of both n-PBZ and i-PBZ(44.79%and 39.26%),while for NaH_(2) PO_(4)·H_(2) O,greater removal rates of two PBZs(47.30%and 42.23%)were achieved at 30 and 20 mg/L,***_(3) supplementation(500-750 mg/L)resulted in a large reduction(43.67%-45.04%)in i-PBZ *** change in seawater pH(from 6 to 9)did not affect the elimination of n-PBZ and *** most suitable salinity and temperature were 30 and 25-30℃,respectively,leading to the PBZs removal of~40%.Light intensity exhibited significant influence on elimination of PBZs,and the maximum removal efficiencies of 56.07%(n-PBZ)and 55.00%(i-PBZ)were recorded under 200 and 600μmol/(m^(2)·s),*** addition,the microalga could still remove PBZs when it failed to grow well due to darkness,strong light,low temperature,or low salinity,which might mean that good growth of alga is not always a necessary condition for PBZs ***,attention should be paid to the suitability of nutrient levels and environmental conditions(excluding pH)in seawater when using microalgae for bioremediating PBZs-contaminated seawater.

关键词： propylbenzene(PBZ) Rhinomonas reticulata seawater inorganic nutrient environmental factor

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Generation and Suppression of Pendant Droplet Oscillation in Electron Beam Directed Energy Deposition

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Engineering 2024年第6期37卷 215-229页

作者： Zhiyue Liang Zhenyu Liao Haoyu Zhang Zixiang Li Li Wang Baohua chang Dong du Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationTsinghua UniversityBeijing 100084China

Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing ***,the effects of EBs on pendant droplets at wire tips have not yet been *** aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet *** pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB–***,another aim of this study is to create an oscillation suppression *** escalating asymmetric amplitude is the main characteristic of droplet *** primary oscillationinducing force is the recoil force generated from the EB-acted local surface of the *** physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the *** prerequisites for droplet oscillation include vacuum conditions,high power densities,and bypass wire feeding *** proposed EB–dynamic surrounding melting(DSM)method can be applied to conveniently and effectively suppress oscillations,enable the accurate transfer of droplets to the molten pool,and achieve stable processes for preparing the strut elements of lattice *** the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB–*** this study,the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB–DED to prepare complex lattice structure parts are provided.

关键词： Additive manufacturing Electron beam freeform fabrication In situ monitoring Pendant droplet

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Compositional and Hollow Engineering of Silicon Carbide/Carbon Microspheres as High-Performance Microwave Absorbing Materials with Good Environmental Tolerance

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Nano-Micro Letters 2024年第9期16卷 128-146页

作者： Lixue Gai Yahui Wang Pan Wan Shuping Yu Yongzheng Chen Xijiang Han ping Xu Yunchen du MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001People’s Republic of China Anhui Provincial Laboratory of Advanced Laser Technology College of Electronic EngineeringNational University of Defense TechnologyHefei 230037People’s Republic of China

Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical *** silicon carbide and carbon are considered as stable MAMs under some rigorous conditions,while their composites still fail to produce satisfactory microwave absorption performance regardless of the improvements as compared with the ***,we have successfully implemented compositional and structural engineering to fabricate hollow Si C/C microspheres with controllable *** simultaneous modulation on dielectric properties and impedance matching can be easily achieved as the change in the composition of these *** formation of hollow structure not only favors lightweight feature,but also generates considerable contribution to microwave attenuation *** the synergistic effect of composition and structure,the optimized SiC/C composite exhibits excellent performance,whose the strongest reflection loss intensity and broadest effective absorption reach-60.8 dB and 5.1 GHz,respectively,and its microwave absorption properties are actually superior to those of most SiC/C composites in previous *** addition,the stability tests of microwave absorption capacity after exposure to harsh conditions and Radar Cross Section simulation data demonstrate that hollow SiC/C microspheres from compositional and structural optimization have a bright prospect in practical applications.

关键词： SiC/C composites Compositional engineering Hollow engineering Microwave absorption Environmental tolerance

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Anisotropic shearing mechanism of Kangding slate:Experimental investigation and numerical analysis

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1487-1504页

作者： ping Liu Quansheng Liu Penghai Deng Yucong Pan Yiming Lei Chenglei du Xianqi Xie The Key Laboratory of Geotechnical and Structural Engineering Safety of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

The shear mechanical behavior is regarded as an essential factor affecting the stability of the surrounding rocks in underground *** shear strength and failure mechanisms of layered rock are significantly affected by the foliation *** shear tests were conducted on cubic slate samples with foliation angles of 0°,30°,45°,60°,and 90°.The effect of foliation angles on failure patterns,acoustic emission(AE)characteristics,and shear strength parameters was *** on AE characteristics,the slate failure process could be divided into four stages:quiet period,step-like increasing period,dramatic increasing period,and remission period.A new empirical expression of cohesion for layered rock was proposed,which was compared with linear and sinusoidal cohesion expressions based on the results made by this paper and previous *** comparative analysis demonstrated that the new expression has better prediction ability than other *** proposed empirical equation was used for direct shear simulations with the combined finite-discrete element method(FDEM),and it was found to align well with the experimental *** both computational efficiency and accuracy,it was recommended to use a shear rate of 0.01 m/s for FDEM to carry out direct shear *** balance the relationship between the number of elements and the simulation results in the direct shear simulations,the recommended element size is 1 mm.

关键词： Anisotropy Empirical expression of cohesion foliation angles Combined finite-discrete element method(FDEM) Shear rate Element size

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Low Surface Brightness Galaxies from BASS+MzLS with Machine Learning

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Research in Astronomy and Astrophysics 2024年第5期24卷 185-197页

作者： Peng-Liang du Wei du Bing-Qing Zhang Zhen-ping Yi Min He Hong Wu Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai 264209China

From ∼5000 deg^(2) of the combination of the Beijing–Arizona Sky Survey and Mayall z-band Legacy Survey which is also the northern sky region of the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, we selected a sample of 31,825 candidates of low surface brightness galaxies (LSBGs) with the mean effective surface brightness 24.2 0.60) LSBGs. The blue LSBGs appear spiral, disk or irregular while the red LSBGs are spheroidal or elliptical and spatially clustered. This trend shows that the color has a strong correlation with galaxy morphology for LSBGs. In the spatial distribution, the blue LSBGs are more uniformly distributed while the red ones are highly clustered, indicating that red LSBGs preferentially populate a denser environment than the blue LSBGs. Besides, both populations have a consistent distribution of ellipticity (median ∈∼ 0.3), half-light radius (median r_(eff) ∼ 4″) and Sérsic index (median n=1), implying the dominance of the full sample by the round and disk galaxies. This sample has definitely extended the studies of LSBGs to a regime of lower surface brightness, fainter magnitude and broader other properties than the previously Sloan Digital Sky Survey-based samples.

关键词： catalogs-galaxies fundamental parameters-galaxies statistics-techniques photometric

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