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大学数学 2005年第6期21卷 116-117页

作者：张广计西北政法学院经贸系陕西西安710063

在度量空间中,通过对函数在一个列紧集S的聚点附近的有界性讨论,给出了函数在整个点集S上有界性的判定方法.

关键词：聚点或极限点有界性列紧集

Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

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World Journal of Stem Cells 2024年第5期16卷 499-511页

作者： Shuai zhang Chuan Lu Sheng Zheng guang Hong Division for International Collaborative and Innovative Dentistry Tohoku University Graduate School of DentistrySendai 980-8575MiyagiJapan School of Stomatology Zhejiang Chinese Medical UniversityHangzhou 310053Zhejiang ProvinceChina

BACKGROUND Bone healing is a complex process involving early inflammatory immune regu-lation,angiogenesis,osteogenic differentiation,and *** repair poses challenges for orthopedic surgeons,necessitating the search for efficient healing *** To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells(BMSCs)facilitate the process of fracture *** Hydrogels and loaded BMSC-derived exosome(BMSC-exo)gels were charac-terized to validate their *** vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing *** could recruit macrophages and inhibit inflammatory responses,enhance of human umbilical vein endothelial cell angiogenesis,and promote the osteogenic differen-tiation of primary cranial ***,the effect of hydrogel on fracture healing was confirmed using a mouse fracture *** The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration,promoted the formation of large vessels,and enabled functional vascularization during bone *** effects were further validated in fracture *** We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

关键词： Hydrogel Bone marrow mesenchymal stem cells Macrophage polarization Angiogenesis Bone regeneration

Event-triggered adaptive output feedback control for hyperbolic PDEs: swapping-based design

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Science China(Information Sciences) 2024年第5期67卷 327-328页

作者： Chunting ji Zhengqiang zhang Xue-Jun XIE School of Engineering Qufu Normal University Institute of Automation Qufu Normal University

Partial differential equations(PDEs) characterize transport phenomena and fluid flow, and common cases include heat exchangers and road traffic [1]. Recently, scholars have become enthusiastic about event-triggered control(ETC) of hyperbolic PDEs, primarily because it can help conserve computing and communication resources. For example,Ref. [2] presented an output feedback ETC scheme for 2 × 2hyperbolic PDEs.

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Cyclic Beam Direction of Arrival Estimation Method for Ship Propeller Noise

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Journal of Ocean University of China 2024年第4期23卷 883-896页

作者： zhang Xiaowei NIE Weihang XU ji YAN Yonghong The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsChinese Academy of SciencesBeijing 100190China The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsUniversity of Chinese Academy of SciencesBeijing 100049China The State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

In underwater acoustic applications,the conventional cyclic direction of arrival algorithm faces challenges,including a low signal-to-noise ratio and high bandwidth when compared with modulated *** response to these issues,this paper introduces a novel,robust,and broadband cyclic beamforming *** proposed method substitutes the conventional cyclic covariance matrix with the variance of the cyclic covariance matrix as its primary *** that the same frequency band shares a common steering vector,the new algorithm achieves superior detection performance for targets with specific modulation frequencies while suppressing interference signals and background *** results demonstrate a significant enhancement in the directibity index by 81%and 181%when compared with the traditional Capon beamforming algorithm and the traditional extended wideband spectral cyclic MUSIC(EWSCM)algorithm,***,the proposed algorithm substantially reduces computational complexity to 1/40th of that of the EWSCM algorithm,employing frequency band statistical averaging and covariance matrix variance.

关键词： cyclostationarity direction of arrival extended wideband spectral cyclic music cyclic covariance matrix

Selective nickel-electrocatalyzed benzylic C-H oxygenation of functionalized alkyl arenes

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Chinese Chemical Letters 2024年第2期35卷 396-401页

作者： Shunyao Tang Siyi Wang Dongmei zhang Xinxing zhang guang Yang Yanwei Wang Youai Qiu State Key Laboratory of Elemento-Organic Chemistry Frontiers Science Center for New Organic MatterCollege of ChemistryNankai UniversityTianjin 300071China College of Chemistry Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education)Renewable Energy Conversion and Storage Center (RECAST)Frontiers Science Center for New Organic MatterNankai UniversityTianjin 300071China

Herein, a site-selective paired electrochemical C–H oxidation of functionalized alkyl arenes promoted by nickel catalyst is disclosed. A Ni(Ⅱ)-dioxygen species formed in situ efficiently enable the oxidation process under mild conditions with a broad substrate scope with excellent functional group compatibilities,such as free carboxylic acid, aldehyde, halogen(including aryl iodide), amide and amino acid. The use of the nickel catalyst in combination with water provides a safe, green and economical method for oxidation of a range of molecules varying in complexity and drug derivatives, demonstrating its potential application in organic synthesis and the pharmaceutical industry. Reaction outcomes and mechanistic studies revealed the key role of the in situ Ni(Ⅱ)-dioxygen species for the subsequent oxidation of C(sp^(3))–H bonds,and short-lived reactive intermediates(aryl radical cation) was rapidly captured by the combination of a bipolar ultramicroelectrode(BUME) with nano-electrospray ionization mass spectrometry.

关键词： Electrochemical C-H oxidation Functionalized alkyl arenes Paired nickel-electrocatalysis H_(2)O oxidation Ketones

Short-term prediction of on-street parking occupancy using multivariate variable based on deep learning

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 28-40页

作者： Mengqi Lyu Yanjie ji Chenchen Kuai Shuichao zhang School of Transportation Southeast UniversityNanjing 211189China Shandong Provincial Communications Planning and Design Institute Group Co. Ltd.Jinan 250101China School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo 315211China

Short-term prediction of on-street parking occupancy is essential to the ITS system,which can guide drivers in finding vacant parking *** the spatial dependencies and exogenous dependencies need to be considered simultaneously,which makes short-term prediction of on-street parking occupancy ***,this paper proposes a deep learning model for predicting block-level parking ***,the importance of multiple points of interest(POI)in different buffers is sorted by Boruta,used for feature *** results show that different types of POI data should consider different buffer *** based on the real on-street parking data,long short-term memory(LSTM)that can address the time dependencies is applied to predict the parking *** results demonstrate that LSTM considering POI data after Boruta selection(LSTM(+BORUTA))outperforms other baseline methods,including LSTM,with an average testing MAPE of 11.78%.The selection process of POI data helps LSTM reduce training time and slightly improve the prediction performance,which indicates that complex correlations among the same type of POI data in different buffer zones will also affect the prediction accuracy of *** there are more restaurants on both sides of the street,the prediction performance of LSTM(+BORUTA)is significantly better than that of LSTM.

关键词： Smart parking Parking occupancy Short-term prediction Long short-term memory Boruta

The molecular genetics of PI3K/PTEN/AKT/mTOR pathway in the malformations of cortical development

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Genes & Diseases 2024年第5期11卷 252-271页

作者： Qing Ma guang Chen Ying Li Zhenming Guo Xue zhang NHC and CAMS Key Laboratory of Molecular Probe and Targeted Theranostics Harbin Medical UniversityHarbinHeilongjiang 150000China Department of Urology The Fourth Hospital of Harbin Medical UniversityHarbinHeilongjiang 150000China Department of Child and Adolescent Health School of Public HealthHarbin Medical UniversityHarbinHeilongjiang 150000China Institute for Regenerative Medicine Shanghai East HospitalFrontier Science Center for Stem Cell ResearchSchool of Life Sciences and TechnologyTongji UniversityShanghai 200120China

Malformations of cortical development(MCD)are a group of developmental disorders characterized by abnormal cortical structures caused by genetic or harmful environmental *** kinds of MCD are caused by genetic *** is the common cause of intellectual disability and intractable *** rapid advances in imaging and sequencing technologies,the diagnostic rate of MCD has been increasing,and many potential genes causing MCD have been successively ***,the high genetic heterogeneity of MCD makes it challenging to understand the molecular pathogenesis of MCD and to identify effective targeted ***,in this review,we outline important events of cortical *** we illustrate the progress of molecular genetic studies about MCD focusing on the PI3K/PTEN/AKT/mTOR ***,we briefly discuss the diagnostic methods,disease models,and therapeutic strategies for *** information will facilitate further research on *** the role of the PI3K/PTEN/AKT/mTOR pathway in MCD could lead to a novel strategy for treating MCD-related diseases.

关键词： Epilepsy Gene mutation Genetics Malformations of cortical development PI3K/PTEN/AKT/mTOR pathway

A comprehensive research on wear resistance of GH4169 superalloy in longitudinal-torsional ultrasonic vibration side milling with tool wear and surface quality

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Chinese Journal of Aeronautics 2024年第4期37卷 556-573页

作者： Baoqi CHANG Zhaoxi YI Fen zhang Lian DUAN ji-an DUAN School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of High Performance and Complex Manufacturing Central South UniversityChangsha 410083China School of Physics and Electronics Central South UniversityChangsha 410083China

To improve the service and machining performance of the workpiece, the tool wear mechanisms, surface machining quality, and wear resistance in conventional side milling(CSM)and longitudinal-torsional ultrasonic vibration side milling(LTUVSM) of GH4169 superalloy at different cutting lengths are investigated systematically. Tool wear mechanisms are revealed and the correlation between machined surface quality with tool wear is analyzed correspondingly. Tool wear patterns mainly include adhesive wear, diffusion wear, abrasive wear, and chipping *** surface quality is achieved in LTUVSM due to a maximum reduction of flank wear bandwidth and wear rate by 71.9% and 71.5%, respectively, compared to CSM. The friction coefficient,initial wear stage time, and wear volume of dry sliding wear were measured to evaluate the workpiece wear resistance. The maximum reductions in friction coefficient and wear volume in LTUVSM are 18.2% and 15.8% compared to CSM. The regular ultrasonic vibration textures suppress the friction and the growth of contact nodes in the contact area, decreasing the degree of surface wear, which is demonstrated by a 38.8% increase in initial wear stage time compared to *** conclusion, the workpiece in LTUVSM exhibits higher wear resistance because of the improvement of tool wear and the guarantee of surface quality.

关键词： Dry sliding wear Surface quality Tool wear Ultrasonic vibration Wear resistance

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang ji Yuan Xue-Lian Fu jing-jing Chen jing Hu Zhou-guang Lu Chen Liu guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

基于L＊-格值逻辑上的BCH-代数中的直觉不分明化理想

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模糊系统与数学 2010年第2期24卷 7-14页

作者：王森张广济大连大学信息工程学院数学系辽宁大连116622

在L*-格值逻辑的语义框架下,以L*-格值上的Lukasiewicz蕴涵算子为工具定义了L*-格值逻辑上的直觉不分明化BCH-代数的概念,将用集论所刻画的BCH-代数与理想的概念在L*-格值谓词演算下给予了新的刻画,讨论了直觉不分明化BCH-代数中的理想... 详细信息

在L*-格值逻辑的语义框架下,以L*-格值上的Lukasiewicz蕴涵算子为工具定义了L*-格值逻辑上的直觉不分明化BCH-代数的概念,将用集论所刻画的BCH-代数与理想的概念在L*-格值谓词演算下给予了新的刻画,讨论了直觉不分明化BCH-代数中的理想、闭理想及q理想的有关性质。

关键词： L*-格值 Lukasiewicz蕴涵算子闭理想 q理想直觉不分明化BCH-代数