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Copper Carboxylate-phosphonates: Syntheses,Crystal Structures and Magnetic Properties

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Chinese Journal of Structural Chemistry 2021年第8期40卷 1061-1067,970页

作者： xu yan Department of Materials Science and Engineering Suqian UniversitySuqian 223800China

Two novel copper carboxyly-phosphonates,namely,Cu2.5(5-pnc)(SO_(4))0.5(OH)(H_(2)O)0.5(1)and Cu0.5(5-pncH2)(H2O)1.5(2)(5-pncH3=5-phosphono-1-naphthalenecarboxylic acid),have been synthesized and characterized by X-ray diffraction,infrared spectroscopy,elemental analysis,and thermogravimetric *** compound 1,each{PO3C}tetrahedron is corner-shared with two{Cu(1)O4},two{Cu(2)O5}and one{Cu(3)O_(5)},thus forming a one-dimensional inorganic chain along the c axis containing 8-membered rings of[Cu_(3)O_(4)S]and 19-membered cages of[Cu_(5)O_(10)P_(4)].The inorganic chains are further connected by a 5-pnc3-ligand to generate a three-dimensional *** 2 exhibits a one-dimensional structure,in which the inorganic chains of[Cu-O-Cu]n are connected by the organic ligands through hydrogen bonding interactions,forming an infinite two-dimensional *** measurements of 1 indicate that dominant antiferromagnetic interactions are mediated between the Cu^(2+)centers.

关键词： copper carboxylate-phosphonate crystal structure magnetic properties

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On Feasible Region of Droop-based Fast Frequency Response Controller Parameters of Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1690-1695页

作者： Junkai Huang yan xu School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AvenueSingapore

Droop-based fast frequency response(FFR)control of wind turbines can improve the frequency performance of power systems with high penetration of wind *** formulating the feasible region of the droop-based FFR controller parameters can allow system operators to conveniently assess the feasibility of FFR controller parameter settings to comply with system frequency security,and efficiently tune and optimize FFR controller parameters to meet frequency security ***,the feasible region of FFR controller parameters is inherently nonlinear and implicit because the power point tracking controllers of wind turbine would counteract the effect of FFR *** address this issue,this letter proposes a linear feasible region formulation method,where frequency regulation characteristics of wind turbines,the dead band,and reserve limits of generators are all *** effectiveness of the proposed method and its application is demonstrated on a 10-machine power system.

关键词： Wind turbine fast frequency response feasible region frequency security

Design of Robust Var Reserve Contract for Enhancing Reactive Power Ancillary Service Market Efficiency

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 767-771页

作者： Yunyang Zou yan xu School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, where market power that may arise in the hourly-ahead Var support service market due to system configuration deficiency and market structure flaws can be eliminated by day-ahead contract-based Var reserve service market. Settlement of day-ahead Var reserve contract is formulated as a two-stage robust optimization (TSRO) model considering worst case of uncertainty realization and potential market power that may arise in hourly-ahead market. TSRO with integer recourses is then solved by a new column and constraint generation algorithm. Results show a robust Var reserve contract can fully eliminate market power, and prevent suppliers from manipulating market prices.

关键词： Market efficiency market power reactive power ancillary service two-stage robust optimization Var reserve

The Number of Rooted Circuit Boundary Maps

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Acta Mathematica Sinica,English Series 2010年第9期26卷 1653-1666页

作者： yan xu yan Pei LIU School of Science Tianjin Polytechnic University Tianjin 300160 P. R. China Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

In this article, the authors discuss two kinds of new planar maps： pan-fan maps and circuit boundary maps, and provide explicit expressions about their enumerating functions with different parameters. Meanwhile, two explicit counting formulas for circuit cubic boundary maps with two parameters; the size and the valency of the root-face, are also extracted.

关键词： Rooted map enumerating function enumeration circuit boundary maps

A Census of Petal Bundles by Genus

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Acta Mathematica Sinica,English Series 2008年第6期24卷 937-946页

作者： yan xu yan Pei LIU School of Science Tianjin Polytechnic University Tianjin 300160 P. R. China Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

This paper provides the uniform enumerative functional equation of orientable （nonori-entable） rooted petal bundles with more parameters, and deduces two recursion formulas for calculation. Accordingly, an explicit ... 详细信息

关键词： rooted map enumerating function enumeration petal bundles

SEMI-IMPLICIT SPECTRAL DEFERRED CORRECTION METHODS BASED ON SECOND-ORDER TIME INTEGRATION SCHEMES FOR NONLINEAR PDES

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Journal of Computational Mathematics 2024年第1期42卷 111-133页

作者： Ruihan Guo yan xu School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China

In[20],a semi-implicit spectral deferred correction(SDC)method was proposed,which is efficient for highly nonlinear partial differential equations(PDEs).The semi-implicit SDC method in[20]is based on first-order time integration methods,which are corrected iteratively,with the order of accuracy increased by one for each additional *** this paper,we will develop a class of semi-implicit SDC methods,which are based on second-order time integration methods and the order of accuracy are increased by two for each additional *** spatial discretization,we employ the local discontinuous Galerkin(LDG)method to arrive at fully-discrete schemes,which are high-order accurate in both space and *** experiments are presented to demonstrate the accuracy,efficiency and robustness of the proposed semi-implicit SDC methods for solving complex nonlinear PDEs.

关键词： Spectral deferred correction method Nonlinear PDEs Local discontinuous Galerkin method Second-order scheme

Nanofluidics for sub-single cellular studies:Nascent progress,critical technologies,and future perspectives

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Chinese Chemical Letters 2022年第6期33卷 2799-2806页

作者： Jinbin yang yan xu Department of Chemical Engineering Graduate School of EngineeringOsaka Prefecture UniversitySakaiOsaka 599-8570Japan Japan Science and Technology Agency(JST) PRESTOKawaguchiSaitama332-0012Japan NanoSquare Research Institute Research Center for the 21^(st)CenturyOrganization for Research PromotionOsaka Prefecture UniversitySakaiOsaka 599-8570Japan

In the field of cell studies,there is a burgeoning trend to further downscale the investigation from a single-cell level to a sub-single-cell *** matter is the basic content in cells and correlates with cell ***-single cellular studies focus on the subcellular matter in single cells and aim to understand the details and heterogeneity of individual cells in terms of the subcellular matter or even at the single component/vesicle/molecule ***,sub-single cellular studies can provide deeper insights into fundamental cell biology and the development of new diagnostic and therapeutic technologies and ***,the contents of a single cell are not only ultra-small in volume but also extremely complex in composition,far exceeding the capabilities of most tools used in current cell *** believe that nanofluidics holds great potential in providing ideal tools for sub-single cellular studies,not only because of their capability to handle femtoliter/attoliter-scale samples,but also because of their possibility to manipulate and analyze subcellular matters at the single component/vesicle/molecule level in a high-throughput *** this review,we summarize the efforts in the field of nanofluidics for sub-single cellular studies,focusing on nascent progress and critical technologies that have the potential to overcome the technical *** challenges and future opportunities to integrate with information sciences are also discussed.

关键词： Sub-single cellular matter Single cell Single molecule Extracellular vesicles Nanochannel Femtoliter Attoliter Digital Information sciences

Malware Evasion Attacks Against IoT and Other Devices: An Empirical Study

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Tsinghua Science and Technology 2024年第1期29卷 127-142页

作者： yan xu Deqiang Li Qianmu Li Shouhuai xu School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Department of Computer Science University of Colorado Colorado SpringsColorado SpringsCO 80918USA

The Internet of Things(loT)has grown rapidly due to artificial intelligence driven edge *** enabling many new functions,edge computing devices expand the vulnerability surface and have become the target of malware ***,attackers have used advanced techniques to evade defenses by transforming their malware into functionality-preserving *** systematically analyze such evasion attacks and conduct a large-scale empirical study in this paper to evaluate their impact on *** specifically,we focus on two forms of evasion attacks:obfuscation and adversarial *** the best of our knowledge,this paper is the first to investigate and contrast the two families of evasion attacks *** apply 10 obfuscation attacks and 9 adversarial attacks to 2870 malware *** obtained findings are as follows.(1)Commercial Off-The-Shelf(COTS)malware detectors are vulnerable to evasion attacks.(2)Adversarial attacks affect COTS malware detectors slightly more effectively than obfuscated malware examples.(3)Code similarity detection approaches can be affected by obfuscated examples and are barely affected by adversarial attacks.(4)These attacks can preserve the functionality of original malware examples.

关键词： Android malware obfuscation adversarial examples

“双一流”高校实施本科生导师制的现状与特征

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黑龙江高教研究 2025年第1期43卷 38-44页

作者：戚佳刘继安徐艳茹中国科学院大学北京100049

加强拔尖创新人才自主培养,是服务实现科技自立自强、建设教育强国的必然要求。本科生导师制是培养拔尖创新人才的重要手段。选取33所具有代表性“双一流”高校的87份本科生导师制管理与实施办法文件,采用文本分析法总结梳理目前本科生... 详细信息

加强拔尖创新人才自主培养,是服务实现科技自立自强、建设教育强国的必然要求。本科生导师制是培养拔尖创新人才的重要手段。选取33所具有代表性“双一流”高校的87份本科生导师制管理与实施办法文件,采用文本分析法总结梳理目前本科生导师制管理办法的特征。研究发现,“双一流”高校推行的本科生导师制形式多样,制度在实施理念方面突出人才培养,在管理要求方面注重建立组织运行的保障机制以及强化“德才兼备”的导师述选标准,但存在导师职责泛化、对导师要求较高而激励不足、导师培训内容尚不完善以及普遍缺失学生权利与义务的问题。基于此,为了进一步提升本科生导师制的科学性、完备性和可操作性,提出明确导师职责、完善导师培训与考核、凸显学生权利和义务等对策建议。

关键词：本科生导师制 “双一流”高校人才培养制度文本分析