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空泡动力学中过阻尼系统的存在性分析

力学与实践 2024年第4期46卷 703-710页

作者：张湘晴张宇宁华北电力大学能源动力与机械工程学院华北电力大学电站能量传递转化与系统教育部重点实验室

在空泡动力学研究中，阻尼机制对气泡泡壁运动具有非常重要的影响。空泡动力学中所涉及的阻尼机制一般分为3种：黏性阻尼、热阻尼、声阻尼。本文基于泡壁运动方程，通过理论分析和推导，从主导阻尼机制的角度对气泡半径进行了分区讨论... 详细信息

在空泡动力学研究中，阻尼机制对气泡泡壁运动具有非常重要的影响。空泡动力学中所涉及的阻尼机制一般分为3种：黏性阻尼、热阻尼、声阻尼。本文基于泡壁运动方程，通过理论分析和推导，从主导阻尼机制的角度对气泡半径进行了分区讨论，获得了简化的阻尼比公式，证明了空泡动力学中过阻尼系统的存在性。与亚阻尼系统相比，过阻尼系统中的气泡并非进行衰减的往复简谐振荡，而是从初始位置逐步衰减至平衡位置。

关键词：空泡动力学阻尼比过阻尼亚阻尼空化

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Predictor and ESO-based adaptive tracking control of heterogeneous vehicle platoon

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Science China Technological Sciences 2024年第9期67卷 2842-2852页

作者： SUN ZhiZe LIU Yang zhang LinChuang College of Control Science and Engineering Bohai University College of Automation and Electronic Engineering Qingdao University of Science and Technology College of Information Science and Technology Bohai University

This paper investigates the distributed adaptive platoon tracking problem of third-order heterogeneous vehicles subject to model uncertainties. The design process is divided into two steps. Firstly, an adaptive tracking controller is designed for the dynamic leading vehicle. And then, the distributed adaptive controllers are established for followers. Moreover, the predictor technique is used to improve the estimate performance of the adaptive law, and the total disturbance is approximated and compensated by the variable gain nonlinear extended state observers(NESOs) driven by the estimation error. By introducing the variable gain hyperbolic tangent tracking differentiator(HTTD), the “complexity explosion” problem is avoided. The feasibility and effectiveness of the proposed protocol are verified by simulation tests.

关键词： variable gain NESOs heterogeneous vehicles platoon tracking predictor

Understanding the mechanism of environmental, social, and governance impact on enterprise performance in the context of sustainable development

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Bright, photostable and long-circulating NIR-Ⅱ nanoparticles for whole-process monitoring and evaluation of renal transplantation

Corporate Social Responsibility and Environmental Management 2024年第2期31卷 784-800页

作者： Shi X.K. zhang Q.M. School of Finance Zhejiang Gongshang University Zhejiang Hangzhou China

In transitional economies characterized by digital finance and uncertainty, the environmental, social, and governance (ESG) impact on enterprise performance has become a core issue in the sustainable development of enterprises. The existing literature does not pay attention to the simultaneous existence of digital finance and economic policy uncertainty in transition countries such as China. This paper introduces ESG as intangible capital into the Cobb–Douglas production function, considers the impact of digital finance and economic policy uncertainty, establishes a theoretical analysis framework, and empirically tests the impact of ESG on enterprise performance using panel data of 1688 listed companies in China from 2011 to 2020. The results reveal that ESG promotes enterprise performance; digital finance strengthens the positive impact of ESG on enterprise performance, and increased economic policy uncertainty strengthens the positive moderating effect of digital finance. Heterogeneity analysis reveals that the impact of ESG on enterprise performance and the moderating effect of digital finance are significant in both the eastern region and the central and western regions, but the former performs better when economic policy uncertainty increases. The research conclusion provides a policy reference for selecting appropriate digital finance policies to promote the sustainable development of enterprises with ESG as the core. © 2023 ERP Environment and John Wiley & Sons Ltd.

关键词： digital finance economic policy uncertainty enterprise performance ESG

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National Science Review 2024年第2期11卷 207-220页

作者： Rongyuan zhang Ping Shen Yu Xiong Tianjing Wu Gang Wang Yucheng Wang Liping zhang Han Yang Wei He Jian Du Xuedong Wei Siwei zhang Zijie Qiu Weijie zhang Zheng Zhao Ben Zhong Tang Clinical Translational Research Center of Aggregation-Induced Emission The Second Affiliated HospitalSchool of MedicineSchool of Science and Engineering Shenzhen Institute of Aggregate Science and TechnologyThe Chinese University of Hong KongShenzhen(CUHK-Shenzhen) Center for AIE Research Shenzhen Key Laboratory of Polymer Science and TechnologyGuangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and Engineering Shenzhen University School of Chemistry Xiangtan University HKUST-Shenzhen Research Institute Department of Chemistry Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction The Hong Kong University of Science and Technology Department of Urology The First Affiliated Hospital of Soochow University AIE Institute

Kidney transplantation is the gold standard for the treatment of end-stage renal diseases(ESRDs). However,the scarcity of donor kidneys has caused more and more ESRD patients to be stuck on the waiting list for transplant surgery. Improving the survival rate for renal grafts is an alternative solution to the shortage of donor kidneys. Therefore, real-time monitoring of the surgical process is crucial to the success of kidney transplantation, but efficient methods and techniques are lacking. Herein, a fluorescence technology based on bright, photostable and long-circulating aggregation-induced emission(AIE) active NIR-II nano-contrast agent DIPT-ICF nanoparticles for the whole-process monitoring and evaluation of renal transplantation has been reported. In the aggregated state, DIPT-ICF exhibits superior photophysical properties compared with the commercial dyes IR-26 and IR-1061. Besides, the long-circulating characteristic of the AIE nano-contrast agent helps to achieve renal angiography in kidney retrieval surgery,donor kidney quality evaluation, diagnosing vascular and ureteral complications, and assessment of renal graft reperfusion beyond renovascular reconstruction, which considerably outperforms the clinically approved indocyanine green(ICG).

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Chien-physics-informed neural networks for solving singularly perturbed boundary-layer problems

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1467-1480页

作者： Long WANG Lei zhang Guowei HE The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences

A physics-informed neural network(PINN) is a powerful tool for solving differential equations in solid and fluid mechanics. However, it suffers from singularly perturbed boundary-layer problems in which there exist sharp changes caused by a small perturbation parameter multiplying the highest-order derivatives. In this paper, we introduce Chien's composite expansion method into PINNs, and propose a novel architecture for the PINNs, namely, the Chien-PINN(C-PINN) method. This novel PINN method is validated by singularly perturbed differential equations, and successfully solves the wellknown thin plate bending problems. In particular, no cumbersome matching conditions are needed for the C-PINN method, compared with the previous studies based on matched asymptotic expansions.

关键词： 34E15 68T01 boundary-layer problem composite asymptotic expansion O302 physics-informed neural network (PINN) singular perturbation

Boosted Electrocatalytic Glucose Oxidation Reaction on Noble-Metal-Free MoO_(3)-Decorated Carbon Nanotubes

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Transactions of Tianjin University 2024年第1期30卷 63-73页

作者： Yu-Long Men Ning Dou Yiyi Zhao Yan Huang Lei zhang Peng Liu Department of Chemical Engineering School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Thyroid Breast and Vascular Surgery Shanghai Fourth People’s Hospital Affi liated to Tongji University School of MedicineShanghai 200081China Department of Vascular Surgery Changhai HospitalNaval Medical UniversityShanghai 200433China

Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell ***,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge process to prepare a noblemetal-free MC-60 catalyst containing MoO_(3),Mo_(2)C,and a Mo_(2)C–MoO_(3)*** the GOR,MC-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/CNT(270μA/(mmol/L cm^(2)))and Au/CNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on MC-60 is as low as 8μmol/L,with a steady-state response time of only 3 ***,MC-60 has superior stability and anti-interference ability to impurities in the *** better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO_(3)–Mo_(2)C *** Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing MC-60 performance in the ***,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.

关键词： Interface eff ect Electrocatalysis Molybdenum oxide Glucose Oxidation reaction

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A polynomial resultant approach to algebraic constructions of extremal graphs

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Science China Mathematics 2024年

作者： Tao zhang Zixiang Xu Gennian Ge Institute of Mathematics and Interdisciplinary Sciences Xidian University School of Mathematical Sciences Capital Normal University

The Turan problem asks for the largest number of edges ex（n, H） in an n-vertex graph not containing a fixed forbidden subgraph H, which is one of the most important problems in extremal graph theory. However,the order of magnitude of ex（n, H） for bipartite graphs is known only in a handful of cases. In particular,giving explicit constructions of extremal graphs is very challenging in this field. In this paper, we develop a polynomial resultant approach to the algebraic construction of explicit extremal graphs, which can efficiently decide whether a specified structure exists. A key insight in our approach is the multipolynomial resultant, which is a fundamental tool of computational algebraic geometry. Our main results include the matched lower bounds on the Turan number of 1-subdivision of K3,t1and the linear Turan number of the Berge theta hypergraphΘ3B,t2, where t1= 25 and t2= 217. Moreover, the constant t1 improves the random algebraic construction of Bukh and Conlon（2018） and makes the known estimation better on the smallest value of t1 concerning a problem posed by Conlon et al.（2021） by reducing the value from a magnitude of 1056 to the number 25, while the constant t2improves a result of He and Tait（2019）.

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Beta-alanine promotes angiogenesis in laser-induced choroidal neovascularization mice models

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International Journal of Ophthalmology(English edition) 2024年第9期17卷 1592-1598页

作者： Jia-Li Wu Min zhang Xiao-Dong Sun Department of Ophthalmology Shanghai General Hospital(Shanghai First People’s Hospital)Shanghai Jiao Tong UniversitySchool of MedicineShanghai 200080China National Clinical Research Center for Ophthalmic Diseases Shanghai 200080China National Clinical Research Center for Eye Diseases Shanghai 200080China Shanghai Key Laboratory of Fundus Diseases Shanghai 200080China Shanghai Engineering Center for Visual Science and Photomedicine Shanghai 200080China

AIM:To investigate the effect ofβ-alanine(BA)on laserinduced choroidal neovascularization(CNV)mice ***:Laser-induced CNV mice models were established,and BA was administrated for one week and two weeks in advance,***,retinal pigment epithelium(RPE)-choroid flat mounts were separated,and immunohistochemical staining was *** laser-induced CNV lesion areas were measured and *** addition,liver and kidney morphologies were observed to identify potential hepatorenal ***:Enlarged CNV lesion areas were observed in the BA treated *** significant differences were observed in the liver and kidney sections between ***:BA treatment increase CNV lesion areas,suggesting the detrimental effects of BA as a nutritional supplement in age-related macular degeneration(AMD)population.

关键词： age-related macular degeneration choroidal neovascularization β-alanine angiogenesis

基于数据融合的中国东部降水氢稳定同位素数据集

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中国科学:地球科学 2024年第9期54卷 3023-3039页

作者：陈佳澄陈杰 Xunchang John zhang 彭培艺武汉大学水资源工程与调度全国重点实验室武汉大学海绵城市建设水系统科学湖北省重点实验室 USDA-ARS Oklahoma and Central Plains Agricultural Research Center 重庆交通大学西南水利水运工程科学研究院

降水氢稳定同位素在气候和水文研究中是一种有效的环境示踪剂.然而,中国目前仍然缺乏高精度的降水氢同位素数据.本研究使用基于卷积神经网络(CNN)的数据融合方法,将观测和引入同位素的大气环流模式(iGCM)模拟的氢同位素组成进行融合,建... 详细信息

降水氢稳定同位素在气候和水文研究中是一种有效的环境示踪剂.然而,中国目前仍然缺乏高精度的降水氢同位素数据.本研究使用基于卷积神经网络(CNN)的数据融合方法,将观测和引入同位素的大气环流模式(iGCM)模拟的氢同位素组成进行融合,建立了中国东部地区1969～2017年降水氢同位素数据集.该数据集的时间分辨率为逐月,空间分辨率为50～60km.在构建数据集之前,比较了三种数据融合方法和两种偏差校正方法的性能.结果表明,基于CNN的融合方法表现最好(与观测数据的相关系数大于0.90,均方根误差小于10.5‰),误差反向传播神经网络和长短期记忆人工神经网络的表现相近,且优于偏差校正方法.因此,使用CNN方法建立数据集并基于此分析了中国东部降水氢同位素的时空分布特征.数据集的降水氢同位素分布与观测数据分布相似,在空间上与北方地区的温度效应和南方地区的降水量效应一致,时间序列变化趋势与降水和气温的观测变化趋势一致.综上所述,构建的数据集能较好地再现观测数据,且具有时间连续和空间相对规则的特点,能为追踪大气和水文过程提供有效的数据支撑.

关键词：降水稳定同位素大气环流模式数据融合数据集

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