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Chemical reactions and thermal stress induced microstructure evolution in 2D-C_(f)/ZrB_(2)-SiC composites

Journal of Materials Science & Technology 2021年第24期83卷 75-82页

作者： Bo-Wen Chen de-wei ni Chun-Jing Liao You-Lin Jiang Jun Lu Yu-Sheng Ding Hong-Da Wang Shao-Ming Dong State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Fibers degradation and matrix cracks are very common during fabrication of composites,which seriously reduces the reliability and properties of the *** this work,2 D-C_(f)/Zr B_(2)-Si C composites were fabricated by a joint processing of slurry infiltration and hot *** on thermal kinetics calculation,finite element simulation and detailed microstructure characterization,fibers degradation and matrix cracks formation mechanisms of the composites are discussed and *** impurities including SiO_(2)and ZrO_(2)react with carbon fibers,resulting in formation of Zr C,Si C particles and etching pits on the fibers,which also leads to a strong bonding between the fibers and *** the other hand,thermal expansion mismatch between the fibers and matrix gives rise to serious thermal stress in the *** thermal stress distribution and development are analyzed by finite element simulation,which is in good agreement with the cracks’formation in the *** on the revealed microstructure evolution mechanisms,a potential solution to mitigate fibers degradation and matrix cracks is put forward.

关键词： Ceramic matrix composites Carbon fiber Residual stress

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Rethinking the Encoder-decoder Structure in Medical Image Segmentation from Releasing decoder Structure

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Journal of Bionic Engineering 2024年第3期21卷 1511-1521页

作者： Jiajia ni wei Mu An Pan Zhengming Chen School of Artificial Intelligence Anhui Polytechnic UniversityWuhu241000China School of Information Science and Engineering HoHai UniversityChangzhou213000China

Medical image segmentation has witnessed rapid advancements with the emergence of encoder-decoder based *** the encoder-decoder structure,the primary goal of the decoding phase is not only to restore feature map resolution,but also to mitigate the loss of feature information incurred during the encoding ***,this approach gives rise to a challenge:multiple up-sampling operations in the decoder segment result in the loss of feature *** address this challenge,we propose a novel network that removes the decoding structure to reduce feature information loss(CBL-Net).In particular,we introduce a Parallel Pooling Module(PPM)to counteract the feature information loss stemming from conventional and pooling operations during the encoding ***,we incorporate a Multiplexed Dilation Convolution(MDC)module to expand the network's receptive ***,although we have removed the decoding stage,we still need to recover the feature map ***,we introduced the Global Feature Recovery(GFR)*** uses attention mechanism for the image feature map resolution recovery,which can effectively reduce the loss of feature *** conduct extensive experimental evaluations on three publicly available medical image segmentation datasets:DRIVE,CHASEDB and MoNuSeg *** results show that our proposed network outperforms state-of-the-art methods in medical image *** addition,it achieves higher efficiency than the current network of coding and decoding structures by eliminating the decoding component.

关键词： Medical image segmentation Encoder-decoder architecture Attention mechanisms Releasing decoder architecture Neural network

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Energy-efficient joint UAV secure communication and 3D trajectory optimization assisted by reconfigurable intelligent surfaces in the presence of eavesdroppers

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defence Technology（防务技术） 2024年第1期31卷 537-543页

作者： Huang Hailong Mohsen Eskandari Andrey V.Savkin wei ni The department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Electrical Engineering and Telecommunications University of New South WalesSydney2052Australia Data61 CSIROAustralia

We consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple *** friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the *** formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given *** present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the *** effectiveness of the proposed method is validated via computer simulations.

关键词： Unmanned aerial systems(UASs) Unmanned aerial vehicle(UAV) Communication security Eaves-dropping Reconfigurable intelligent surfaces(RIS) Autonomous navigation and placement Path planning Model predictive control

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Transjugular intrahepatic portosystemic shunt:A promising therapy for recompensation in cirrhotic patients

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World Journal of Gastroenterology 2024年第16期30卷 2285-2286页

作者： Ya-ni Jin wei Zhang department of Gastroenterology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210000Jiangsu ProvinceChina

This is a retrospective study focused on recompensation after transjugular intrahepatic portosystemic shunt(TIPS)*** authors confirmed TIPS could be a treatment for recompensation of patients with cirrhosis according to Baveno *** paper identified age and post-TIPS portal pressure gradient as independent predictors of recompensation in patients with decompensated cirrhosis after *** results need to be validated in a larger prospective cohort.

关键词： Cirrhosis recompensation Transjugular intrahepatic portosystemic shunt Portal pressure gradient Predictor factor Baveno VII

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niCoZn/C@melamine sponge-derived carbon composites with highperformance electromagnetic wave absorption

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2274-2286页

作者： Xiubo Xie Heshan Wang Hideo Kimura Cui ni wei Du Guanglei Wu School of Environmental and Material Engineering Yantai UniversityYantai 264005China Shandong Key Laboratory of Eco-Environmental Science for the Yellow River delta Shandong University of AeronauticsBinzhou 256603China Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China

niMZn/C@melamine sponge-derived carbon(MSDC)composites(M=Co,Fe,and Mn)were prepared by a vacuum pump-ing solution method followed by carbonization.A large number of carbon nanotubes(CNTs)homogeneously attached to the surfaces of the three-dimensional cross-linked of the sponge-derived carbon in the niCoZn/C@MSDC composite,and CNTs were detected in the niFeZn/C@MSDC and niMnZn/C@MSDC ***_(3)ZnC_(0.7),ni_(3)Fe,and MnO in-situ formed in the niFeZn/C@MSDC and niMnZn/C@MSDC *** CNTs in the niCoZn/C@MSDC composite efficiently modulated its complex ***,the composite exhibited the best performance among the composites,with the minimum reflection loss(RL_(min))of-33.1 dB at 18 GHz and thickness of 1.4 *** bandwidth for RL of≤-10 dB was up to 5.04 GHz at the thickness of 1.7 mm and loading of 25wt%.The op-timized impedance matching,enhanced interfacial and dipole polarization,remarkable conduction loss,and multiple reflections and scat-tering of the incident microwaves improved the microwave absorption *** effects of Co,ni,and Fe on the phase and mor-phology provided an alternative way for developing highly efficient and broadband microwave absorbers.

关键词： microwave absorption carbon nanotube element substitution melamine sponge-derived carbon

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Multi-Fidelity Simulation of Gas Turbine Overall Performance by Directly Coupling High-Fidelity Models of Multiple Rotating Components

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Journal of Thermal Science 2024年第4期33卷 1357-1378页

作者： deNG weimin XU Yibing ni Ming wei Zuojun GAN Xiaohua REN Guangming department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen518055China School of Aerospace Engineering Tsinghua UniversityBeijing100084China Shenzhen Key Laboratory of Wide-Speed-Range and Variable-density Continuous Wind Tunnel Shenzhen Science and Technology Innovation CommitteeShenzhen518000China

Multi-fidelity simulations incorporate computational fluid dynamics(CFD) models into a thermodynamic model,enabling the simulation of the overall performance of an entire gas turbine with high-fidelity *** iterative coupled methods rely on characteristic maps,while fully coupled methods directly incorporate high-fidelity ***,fully coupled methods face challenges in simulating rotating components,including weak convergence and complex *** address these challenges,a fully coupled method with logarithmic transformations was developed to directly integrate high-fidelity CFD models of multiple rotating *** developed fully coupled method was then applied to evaluate the overall performance of a KJ66 micro gas turbine across various off-design *** developed fully coupled method was also compared with the traditional iterative coupled ***,experimental data from ground tests were conducted to verify its *** convergence history indicated that the proposed fully coupled method exhibited stable convergence,even under far-off-design *** experimental verification demonstrated that the multi-fidelity simulation with the fully coupled method achieved high accuracy in off-design *** analysis revealed inherent differences in the coupling methods of CFD models between the developed fully coupled and traditional iterative coupled *** inherent differences provide valuable insights for reducing errors between the component-level model and CFD models in different coupling *** developed fully coupled method,introducing logarithmic transformations,offers more realistic support for the detailed and optimal design of high-fidelity rotating components within the overall performance platform of gas turbines.

关键词： multi-fidelity fully coupled method iterative coupled method gas turbine component-level model

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Effects of different concentrations of nicotinamide on hematopoietic stem cells cultured in vitro

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World Journal of Stem Cells 2024年第2期16卷 163-175页

作者： Yan Ren Yan-ni Cui Hong-wei Wang The Second Clinical Medical College Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina department of Hematology The Second Hospital of Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina department of Hematology Key Laboratory of Molecular Diagnosis and Treatment of Blood Diseases in Shanxi ProvinceTaiyuan 030001Shanxi ProvinceChina

BACKGROUND In vitro expansion to increase numbers of hematopoietic stem cells(HSCs)in cord blood could improve clinical efficacy of this vital ***(NAM)can promote HSC expansion ex vivo,but its effect on hematopoietic stem and progenitor cells(HSPCs,CD34^(+)CD38)and functional subtypes of HSCs-shortterm repopulating HSCs(ST-HSCs,CD34^(+)CD38CD45RACD49f^(+))and long-term repopulating HSCs(LT-HSCs,CD34^(+)CD38CD45RACD49f^(+)CD90^(+))is not yet *** a sirtuin 1(SIRT1)inhibitor,NAM participates in regulating cell adhesion,polarity,migration,proliferation,and ***,SIRT1 exhibits dual effects by promoting or inhibiting differentiation in different tissues or *** propose that the concentration of NAM may influence proliferation,differentiation,and SIRT1 signaling of *** To evaluate the effects and underlying mechanisms of action of different concentrations of NAM on HSC proliferation and *** CD34^(+)cells were purified from umbilical cord blood using MacsCD34 beads,and cultured for 10-12 d in a serum-free medium supplemented with cytokines,with different concentrations of NAM added according to experimental *** cytometry was used to detect phenotype,cell cycle distribution,and apoptosis of the cultured ***-time polymerase chain reaction was used to detect the transcription levels of target genes encoding stemness-related factors,che mokines,components of hypoxia pathways,and antioxidant ***-dihydro-fluorescein diacetate probes were used to evaluate intracellular production of reactive oxygen species(ROS).determination of the effect of different culture conditions on the balance of cytokine by cytometric bead *** Compared with the control group,the proportion and expansion folds of HSPCs(CD34^(+)CD38)incubated with 5 mmol/L or 10 mmol/L NAM were significantly increased(all Pnificantly

关键词： Hematopoietic stem cells nicotinamide Concentration Proliferation Differentiation Sirtuin 1

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Memory Trace for Fear Extinction:Fragile yet Reinforceable

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Neuroscience Bulletin 2024年第6期40卷 777-794页

作者： Ying Liu Shuai Ye Xin-ni Li wei-Guang Li department of Rehabilitation Medicine State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain ScienceHuashan HospitalInstitute for Translational Brain ResearchFudan UniversityShanghai200032China

Fear extinction is a biological process in which learned fear behavior diminishes without anticipated reinforcement,allowing the organism to re-adapt to ever-changing *** on the behavioral hypothesis that extinction is new learning and forms an extinction memory,this new memory is more readily forgettable than the original fear *** brain’s cellular and synaptic traces underpinning this inherently fragile yet reinforceable extinction memory remain *** questions are about the whereabouts of the engram neurons that emerged during extinction learning and how they constitute a dynamically evolving functional construct that works in concert to store and express the extinction *** this review,we discuss recent advances in the engram circuits and their neural connectivity plasticity for fear extinction,aiming to establish a conceptual framework for understanding the dynamic competition between fear and extinction memories in adaptive control of conditioned fear responses.

关键词： Fear extinction memory Memory trace Fear relapse Medial prefrontal cortex Basolateral amygdala Ventral hippocampus Insular cortex Synaptic adaptations

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Ceramic-based meta-material absorber with high-temperature stability

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Rare Metals 2024年第9期43卷 4433-4440页

作者： Xing-Cong Chen wei-Jia Luo Run-ni Zhao Yong-Zheng Wen Ji Zhou State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

With the continuous exploration of uncharted and extreme environments,enhanced temperature robustness of passive devices has become particularly *** this study,a ceramic-based meta-material absorber with exceptional temperature stability is developed using a fusion design approach that combines rare metal-based tungsten bronze structural ceramics and ***,the absorbance of the meta-material array based on Mie resonance exceeds 49.0%in both waveguides and free space,approaching the theoretical *** to impedance analysis,the absorption performance can be distinctly correlated with the dielectric loss(Q_(f)).Notably,the high-temperature robustness is verified to still be effective at 400℃.These advancements in our design allow for the use of monolithic materials in fabricating temperature-stable perfect absorbers,providing greater freedom in the dielectric performance and expanding their potential applications,including in space exploration and 5G millimeter-wave scenarios.

关键词： Temperature robustness Meta-material absorber Microwave absorption Rare metal-based ceramics Miniaturization

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Stable α-CsPbI3 with extremely red emission for expanding the color gamut

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Science China(Information Sciences) 2024年第5期67卷 311-317页

作者： Yong ZHANG Xin wei Lei GAO weijie ZHAO Changjiu SUN Junli wei Mingjian YUAN Zhenhua ni Junpeng LU Hongwei LIU School of Physics and Key Laboratory of MEMS of the Ministry of Education Southeast University Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center (RECAST) College of Chemistry Nankai University Jiangsu Key Lab on Opto-Electronic Technology School of Physics and TechnologyNanjing Normal University

The wider color gamut represents the better reproducibility of the real natural colors. Perovskite materials exhibit promising potential in full-color wide-gamut displays because of the wide tunability and high saturability of their photon emission. However, the full-color wide gamut(>100% Rec.2020) has not been constructed due to the lack of the extreme red primary color(～700 nm). Herein, the widest color gamut is realized, whereinα-CsPbI3 is used to generate the extreme red primary color. An in-situ encapsulation approach is advised to stabilizeα-CsPbI3 at room temperature by means of polyvinylpyrrolidone(PVP).Theα-CsPbI3 encapsulated by PVP(denoted as P-CPI) shows highly saturated(FWHM(full width at half maximum) ～28 nm) and extremely(～697 nm) red emission. The green emission is provided by P-CPBr(CsPbBr3 with PVP) which is also synthesized using the universal in-situ encapsulation approach. With the assistance of a commercial Ga N chip, the RGB gamut is extended to the widest(151% NTSC, 113%Rec.2020).

关键词： all-inorganic perovskite wide color gamut LED display carrier recombination

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