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Particuology 2024年第7期90卷 404-411页

作者： Hanqiao Che Yuanhe Yue Zhaohua jiang Duan li School of Mechanical Engineering Guangxi UniversityNanningGuangxi530004China School of Chemical Engineering University of BirminghamBirminghamB152TTUK Hebei Engineering Research Center of Advanced Energy Storage Technology and Equipment School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China Hebei Key Laboratory of Thermal Science and Energy Clean Utilization School of Energy and Environmental EngineeringHebei University of TechnologyTianjin300401China School of Mechatronics and Vehicle Engineering Chongqing Jiaotong UniversityChongqing400074China School of Instrumentation and Opto-Electronic Engineering Beihang UniversityBeijing 100191China

The transient heat transfer behaviours in a packed bed have been studied using coupled computational fluid dynamics(CFD)and discrete element method(DEM).Intra-particle thermal diffusion,which is a crucial but rarely explored issue,is considered by introducing a one-dimensional diffusion equation in the DEM *** achieve a sufficiently long physical time of simulations,we further reduce the computational cost by applying periodic boundary condition to a small segment of the packed *** study demonstrates a shifting peak heat flow rate from the bottom to the top of the packed bed during the initial warming *** affirm that the influence of thermal diffusion within a particle is noteworthy only for particles exhibiting a high Biot number(e.g.,Bi=1.2).This insight enriches our understanding of heat transfer mechanisms in packed beds and their practical engineering applications.

关键词： Packed bed Intra-particle heat transfer CFD–DEM

Numerical and experimental investigation into the evolution of the shock wave when a muzzle jet impacts a constrained moving body

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Defence Technology（防务技术） 2024年第3期33卷 317-326页

作者： Zijie li Hao Wang Changshun Chen Kun jiang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210016China

The gun-track launch system is a new special launch device that connects the track outside the *** it is constrained by the track,the characteristics of development of the muzzle jet differ from those of the traditional muzzle ***,it changes from freely developing to doing so in a constrained manner,where this results in an asymmetric direction of flow as well as spatio-temporal coupling-induced interference between various shock waves and the formation of *** this background,the authors of this article formulate and consider the development and characteristics of evolution of the muzzle jet as it impacts a constrained moving *** designed simulations to test the gun-track launch system,and established a numerical model based on the dynamic grid method to explore the development and characteristics of propagation of disturbances when the muzzle jet impacted a constrained moving *** also considered models without a constrained track for the sake of *** results showed that the muzzle jet assumed a circumferential asymmetric shape,and tended to develop in the area above the *** the test platform was close to the ground,the muzzle jet was subjected to reflections from it that enhanced the development and evolution of various forms of shock waves and vortices in the muzzle jet to exacerbate its rate of distortion and asymmetric *** in turn led to significant differences in the changes in pressure at symmetric points that would otherwise have been *** results of a comparative analysis showed that the constrained track could hinder the influence of reflections from the ground on the muzzle jet to some extent,and could reduce the velocity of the shock waves inducing the motion of the muzzle as well as the Mach number of the moving *** work here provides a theoretical basis and the requisite technical support for applications of the gun-track launch *** also sheds light on the

关键词： Shock wave/vortex interference Muzzle jet Constrained boundary Dynamic grid

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Finite-time composite learning control for nonlinear teleoperation systems under networked time-varying delays

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Science China(Information Sciences) 2024年第6期67卷 279-296页

作者： Yana YANG Huixin jiang Changchun HUA Junpeng li Institute of Electrical Engineering Yanshan University

The robust finite-time synchronization control problem is investigated for master-slave networked nonlinear telerobotics systems(NNTSs) in this article. Although there have been some research achievements on finite-time control for the NNTSs, these studies are based on the strong assumptions of communication time delays or can only achieve finite-time bounded convergence even when the external forces are *** and in view of the importance of these issues, a novel robust composite learning adaptive control scheme rendering the finite-time master-slave synchronization is proposed in this paper. In particular, the influence of time delays on finite-time convergence of the system is analyzed by employing the multi-dimension finite-time small-gain framework. Meanwhile, in order to achieve accurate and fast estimation of uncertain parameters of the system, both the online historical and the instantaneous data of the estimation data are explored to derive the new parameter adaptive law under a more realizable interval-excitation(IE) ***, the convergence of the position/force synchronization errors and the adaptive parameter estimation errors is obtained in finite time, and enhanced robustness of the closed-loop system will also be ***, the superior performance of the proposed control algorithms is validated by numerical simulations and hardware experiments.

关键词： networked teleoperation systems finite-time control exact parameter estimation small-gain theorem unknown communication delays

Fault diagnosis of a marine power-generation diesel engine based on the Gramian angular field and a convolutional neural network

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 470-482页

作者： Congyue li Yihuai HU Jiawei jiang Dexin CUI Merchant Marine College Shanghai Maritime UniversityShanghai 201306China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics&InformationShanghai 201411China

Marine power-generation diesel engines operate in harsh *** vibration signals are highly complex and the feature information exhibits a non-linear *** is difficult to extract effective feature information from the network model,resulting in low fault-diagnosis *** address this problem,we propose a fault-diagnosis method that combines the Gramian angular field(GAF)with a convolutional neural network(CNN).Firstly,the vibration signals are transformed into 2D images by taking advantage of the GAF,which preserves the temporal *** raw signals can be mapped to 2D image features such as texture and *** integrate the feature information,the images of the Gramian angular summation field(GASF)and Gramian angular difference field(GADF)are fused by the weighted average fusion ***,the channel attention mechanism and temporal attention mechanism are introduced in the CNN model to optimize the CNN learning *** the concept of residuals in the attention mechanism improves the feasibility of ***,the weighted average fused images are fed into the CNN for feature extraction and fault *** validity of the proposed method is verified by experiments with abnormal valve *** average diagnostic accuracy is 98.40%.When−20 dB≤signal-to-noise ratio(SNR)≤20 dB,the diagnostic accuracy of the proposed method is higher than 94.00%.The proposed method has superior diagnostic ***,it has a certain anti-noise capability and variable-load adaptive capability.

关键词： Multi-attention mechanisms(MAM) Convolutional neural network(CNN) Gramian angular field(GAF) Image fusion Marine power-generation diesel engine Fault diagnosis

3D bioprinting of collagen-based materials for oral medicine

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Collagen and Leather 2024年第1期5卷 28-46页

作者： Bosen Yang hai liu linli jiang Yiwei Zeng Yiyuan Han Chuanlu Sha Xin Xie Hui li Jiajing Zhou Wei lin College of Biomass Science and Engineering Key Laboratory of Leather Chemistry and Engineering of Ministry of EducationNational Engineering Laboratory for Clean Technology of Leather ManufactureSichuan UniversityChengdu 610065China State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesDepartment of Oral and Maxillofacial SurgeryWest China Hospital of StomatologySichuan UniversityChengdu 610065China Laboratory for Biomaterials and Drug Delivery Department of AnesthesiologyDivision of Critical Care MedicineBoston Children's HospitalHarvard Medical SchoolBostonMA 02115USA

Oral diseases have emerged as one of the leading public health challenges *** the existing clinical modalities for restoration of dental tissue loss and craniomaxillofacial injuries can achieve satisfactory therapeutic results,they cannot fully restore the original complex anatomical structure and physiological function of the tissue.3D printing of biological tissues has gained growing interest in the field of oral medicine with the ability to control the bioink component and printing structure for spatially heterogeneous repairing constructs,holding enormous promise for the precise treatment of oral ***,collagen-based materials have been recognized as promising biogenic bioinks for the regeneration of several tissues with high cell-activating and biocompatible *** this review,we summarize 3D printing methods for collagen-based biomaterials and their ***,we highlight the animal sources of collagen and their characteristics,as well as the methods of collagen ***,this review provides an overview of the 3D bioprinting technology for the regeneration of the pulpal nerve and blood vessels,cartilage,and periodontal *** envision that this technique opens up immense opportunities over the conventional ones,with high replicability and customized function,which can ultimately promote effective oral tissue regeneration.

关键词： 3D bioprinting Oral medicine Tissue engineering Collagen Scaffold materials Bioink Hydrogel

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Enhanced carbon capture with motif-rich amino acid loaded defective robust metal-organic frameworks

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Nano Research 2024年第3期17卷 2004-2010页

作者： Qi-Ye Ju Jia-Jia Zheng li Xu hai-Yan jiang Zi-Qian Xue Lu Bai Yang-Yang Guo Ming-Shui Yao Ting-Yu Zhu State Key Laboratory of Multi-phase Complex Systems CAS Key Laboratory of Green Process and EngineeringBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Laboratory of Theoretical and Computational Nanoscience National Center for Nanoscience and TechnologyChinese Academy of SciencesBeijing 100190China School of Rare Earths University of Science and Technology of ChinaHefei 230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Institute for Integrated Cell-Material Sciences Kyoto UniversityInstitute for Advanced StudyKyoto UniversityYoshidaUshinomiya-choSakyokuKyoto 606-8501Japan

The use of metal-organic frameworks(MOFs)as solid adsorption materials for carbon capture is promising,but achieving efficient and reversible adsorption with a balance of capacity and selectivity for carbon dioxide(CO_(2))over N_(2) remains a *** take full advantage of the strong channel traffic and robustness of MOFs with relatively small pores,it is highly necessary to employ a defect-engineering strategy to construct a broader channel structure that can facilitate the loading of functional motif-rich amino acids(AAs).This strategy can greatly enhance the CO_(2) adsorption performance of *** this study,motif-rich amino acids are loaded into the defective and robust porous frameworks via combined defect-engineering and post-synthetic *** defective Zr/Hf-MOF-808s modified with AAs,especially for the 18 mol%4-nitroisophthalic acid,generated defective products allowing for the loading of L-serine(L-Ser).This modification resulted in a significant improvement in both the adsorption capacity(248%improvement at 298 K,100 kPa)and the selectivity of CO_(2)/N_(2) using the ideal adsorbed solution theory(IAST),with the selectivity increasing to 120.55 and 38.27 at 15 and 100 kPa,respectively,while maintaining good cycling *** functional theory(DFT)simulation,CO_(2) temperature-programmed desorption(CO_(2)-TPD),and in situ Fourier transform infrared spectroscopy(FTIR)were further employed to have a better understanding of the enhanced CO_(2) adsorption ***,unlike the AAs loaded pristine MOF-808s that showed the best CO_(2) adsorption capacity with the loading of short and small glycine(Gly),the broadened channel size in our work enables the loading of functional motif-rich L-serine,which brings more active binding sites,improving CO_(2) adsorption.

关键词： carbon capture and storage metal-organic framework(MOF) amino acids(AAs) defect-engineering motif-rich

MXenes/CNTs-based hybrids:Fabrications,mechanisms,and modification strategies for energy and environmental applications

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Nano Research 2024年第5期17卷 3429-3454页

作者： Jizhou jiang Fangyi li Lei Ding Chengxun Zhang Arramel Xin li School of Environmental Ecology and Biological Engineering School of Chemistry and Environmental EngineeringKey Laboratory of Green Chemical Engineering Process of Ministry of EducationEngineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationNovel Catalytic Materials of Hubei Engineering Research CenterWuhan Institute of TechnologyWuhan 430205China Nano Center Indonesia Jl.PUSPIPTEK Tangerang SelatanBanten 15314Indonesia Institute of Biomass Engineering Key Laboratory of Energy Plants Resource and UtilizationMinistry of Agriculture and Rural AffairsSouth China Agricultural UniversityGuangzhou 510642China

Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and *** the past few years,MXenes/carbon nanotubes(CNTs)-based hybrids have attracted extensive attention as an important catalyst in energy and environmental fields,due to their superior multifunctions and mechanical *** review aims to address the fabrication strategies,the identification of the enhancement mechanisms,and recent progress regarding the design and modification of MXenes/CNTs-based hybrids.A myriad of fabrication techniques have been systematically summarized,including mechanical mixing,spray drying,three-dimensional(3D)printing,self-assembly/in-situ growth,freeze drying,templating,hydrothermal methods,chemical vapor deposition(CVD),and ***,the identification of the enhancement mechanisms was thoroughly discussed from the two dimensions of theoretical simulations and in-situ ***,the recent advancements in profound applications of MXenes/CNTs-based hybrids have also been carefully revealed,including energy storage devices,sensors,water purification systems,and microwave *** also underscore anticipated challenges related to their fabrication,structure,underlying mechanisms,modification approaches,and emergent ***,this review offers insights into prospective directions and the future trajectory for these promising *** is expected that this review can inspire new ideas or provide new research methods for future studies.

关键词： MXenes/carbon nanotubes(CNTs)-based hybrids fabrication applications modification strategies

DC Traction Power Supply System Based on Modular Multilevel Converter Suitable for Energy Feeding and De-icing

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 649-659页

作者： lingxi Hou Shuqing Zhang Yingdong Wei Xiaoqian li Qirong jiang Mingrui li Weirui li Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

A novel DC traction power supply system suitable for energy feeding and de-icing is proposed in this paper for an urban rail transit catenary on the basis of the full bridge submodule (FBSM) modular multilevel converter (MMC). The FBSM-MMC is a novel type of voltage source converter (VSC) and can directly control the output DC voltage and conduct bipolar currents, thus flexibly controlling the power flow of the urban rail transit catenary. The proposed topology can overcome the inherent disadvantages of the output voltage drop in the diode rectifier units, increase the power supply distance and reduce the number of traction substations. The flexible DC technology can coordinate multiple FBSM-MMCs in a wide area and jointly complete the bidirectional control of catenary power flow during the operation of the electric locomotive, so as to realize the local consumption and optimal utilization of the recovered braking energy of the train. In addition, the FBSM-MMCs can also adjust the output current when the locomotive is out of service to prevent the catenary from icing in winter. The working modes of the proposed topology are illustrated in detail and the control strategy is specially designed for normal locomotive operations and catenary de-icing. Simulation cases conducted by PSCAD/EMTDC validate the proposed topology and its control strategy.

关键词： DC traction power supply system de-icing for catenary energy feeding modular multilevel converter based on full-bridge submodules(FBSM-MMC) urban rail transit

Effect of miR-124 Overexpression under Wnt/β-catenin Signaling Pathway on Inflammatory Factor and Epidermal Growth Factor in Rats with Precancerous Gastric Lesions

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Chinese Journal of Biomedical Engineering 2024年第1期33卷 17-26页

作者： ZHOU li-jiang Zhejiang Chinese Medical University Shangyu People's Hospital of Shaoxing

Objective: To investigate the effects of miR-124 overexpression on inflammatory factors and epidermal growth factor in rats with gastric precancerous lesions by modulating the Wnt/β-catenin signaling pathway. Methods: Eighty SPF-grade Wistar rats were selected as the research subjects. After adaptive feeding,they were divided into 4 groups using a random number table method. The control group was fed a regular diet, while the model group, low expression group, and overexpression group of rats were treated with N-methyl-N'-nitro-N-nitrosoguanidine to establish a model of gastric cancer precancerous lesions. After successful modeling, the control group and model group rats were injected intraperitoneally with 0.9% sodium chloride solution, the low-expression group rats were injected intraperitoneally with miR-124-5p inhibitor, and the over-expression group rats were injected intraperitoneally with miR-124-5p mimic. After 8 weeks of continuous injection, the levels of miR-124,Wnt/β-catenin signaling pathway-related proteins, inflammatory factors, and epidermal growth factor were observed and compared among the four groups of rats. Results: The differences in the relative expression of miR-124 among the four groups of rats were statistically significant(P<0.05); the differences in the expression of Wnt protein andβ-catenin protein among the four groups of rats were statistically significant(P<0.05),and the expression of Wnt protein and β-catenin protein in the overexpression group was significantly higher than that of the control group, and significantly lower than that in the model group and the low-expression group; the levels of IL-1β, IL-6, and TNF-αof rats in the four groups of rats IL-1β, IL-6 and TNF-α levels were statistically different(P<0.05), and the levels of IL-1β, IL-6 and TNF-α in rats in the overexpression group were higher than those in the model group and significantly lower than those in the model group and the low-expression group(P<0.05); the differ

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FNNWV: farthest-nearest neighbor-based weighted voting for class-imbalanced crowdsourcing

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Science China(Information Sciences) 2024年第10期67卷 172-188页

作者： Wenjun ZHANG liangxiao jiang Ziqi CHEN Chaoqun li School of Computer Science China University of Geosciences Key Laboratory of Artificial Intelligence Ministry of Education School of Mathematics and Physics China University of Geosciences

In crowdsourcing scenarios, we can hire crowd workers to label crowdsourced tasks and then use label integration algorithms to infer the integrated label for each instance in the tasks. As more and more label integration algorithms are proposed, the performance of inference based only on the information of the inferred instance gradually converges. Recent algorithms attempt to exploit the information of the inferred instance's nearest neighbors to infer and achieve good performance. However, when crowdsourced tasks are class-imbalanced, negative instances are more easily to occur in the nearest neighbors because negative instances are the majority, and thus recent algorithms are more easily biased toward the negative class. To this end, in this paper, we propose a novel label integration algorithm called farthest-nearest neighbor-based weighted voting(FNNWV) for class-imbalanced crowdsourcing. Specifically, FNNWV considers the nearest neighbors to be more similar to the inferred instance and thus uses them to vote ayes in weighted voting. Yet at the same time, FNNWV considers the farthest neighbors to be more different from the inferred instance and thus uses them to vote nays in weighted voting. Since negative instances are easier to occur in both the nearest neighbors and the farthest neighbors, FNNWV weakens the effect of negative instances by voting ayes and nays. The experimental results on 22 simulated and one real-world crowdsourced datasets show that FNNWV significantly outperforms all the other state-of-the-art competitors.

关键词： crowdsourcing label integration nearest neighbor farthest neighbor weighted voting