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Study on a straight dislocation in an icosahedral quasicrystal with piezoelectric effects

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Applied Mathematics and Mechanics(English Edition) 2018年第9期39卷 1259-1266页

作者： lianhe li Guanting liU College of Mathematics Science Inner Mongolia Normal University Inner Mongolia Key Laboratory of Nanoscience and Nanotechnology Inner Mongolia University

An electro-elastic analysis is performed on an icosahedral quasicrystal with piezoelectric effects containing a straight dislocation. The closed-form expressions for the elastic and electric fields are obtained using the extended Stroh formalism. The effects of piezoelectric constant on the phonon displacement, phason displacement, and electric potential are discussed in detail.

关键词： icosahedral quasicrystal piezoelectric effect Stroh formalism dislocation

Effect of Operating Condition and Structural Parameter in the Hydrostatic Thrust CO_2 Bearing

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Journal of Thermal Science 2019年第3期28卷 454-462页

作者： li liangliang XIE Yonghui Shaanxi Engineering Laboratory of Turbomachinery and Power Equipment School of Energy and Power EngineeringXi'an Jiaotong University

Hydrostatic thrust bearings are widely applied in rotating machinery field. Its comprehensive performance and safe operation is of great significance for ensuring equipment efficiency. In this paper, the numerical method is adopted to investigate the slit-restricted hydrostatic thrust CO_2 bearing with a small film thickness. The research is carried out from two aspects, which mainly consider the operating conditions and structural parameters. Firstly, the influence of different working fluid types including real air and CO_2(include subcritical and supercritical state) on the static characteristics of bearing is studied, and the results indicate that the bearing with CO_2 as working fluid has a better static performance. Secondly, the influence of rotor rotating speed is studied and the conclusion shows that the rotating speed has a significant effect on bearing static characteristics. Thirdly, the influence of different slit arrangement forms is investigated, and the consequence indicates that the circumferential slits show a better load capacity than that of radial slits, while the flow rate difference is small. Finally, the effect of film thickness on bearing static performance is investigated and the research shows that this factor affects static performance in a dramatical way. When the clearance tends to be smaller, the load capacity increases sharply, while the massflow rate of working fluid decreases.

关键词： slit-restricted supercritical carbon dioxide hydrostatic thrusting bearing slit arrangement film thickness rotating speed

Aeroelastic stability of full-span tiltrotor aircraft model in forward flight

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Chinese Journal of Aeronautics 2017年第6期30卷 1885-1894页

作者： Zhiquan li Pinqi XIA College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The existing full-span models of the tiltrotor aircraft adopted the rigid blade model without considering the coupling relationship among the elastic blade, wing and fuselage. To overcome the limitations of the existing full-span models and improve the precision of aeroelastic analysis of tiltrotor aircraft in forward flight, the aeroelastic stability analysis model of full-span tiltrotor aircraft in forward flight has been presented in this paper by considering the coupling among elastic blade, wing, fuselage and various components. The analytical model is validated by comparing with the calculation results and experimental data in the existing references. The influence of some structural parameters, such as the fuselage degrees of freedom, relative displacement between the hub center and the gravity center, and nacelle length, on the system stability is also investigated. The results show that the fuselage degrees of freedom decrease the critical stability velocity of tiltrotor aircraft, and the variation of the structural parameters has great influence on the system stability,and the instability form of system can change between the anti-symmetric and symmetric wing motions of vertical and chordwise bending.

关键词： Aeroelastic stability Forward flight Full-span model Modal analysis Tiltrotor aircraft

A short non-delegatable strong designated verifier signature

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Frontiers of Computer Science 2014年第3期8卷 490-502页

作者： Haibo TIAN Jin li School of Information Science and Technology Sun Yat-Sen University Guangzhou 510275 China School of Computer Science Guangzhou University Guangzhou 510006 China

A non-delegatable strong designated verifier signature （NSDVS） enforces verification of a signature by a designated verifier only. The concept is useful in various commercial cryptographic applications such as copyright protection, e-voting, and e-libraries. This paper reports the shortest NSDVS so far that consists of only two elements. The scheme is inspired by an identification scheme and Cramer et al.＇s OR-proof technique where a prover can prove that he knows at least one out two secrets. It is solidified by a symmetric key based group to group encryption algorithm. Two implementations of the algorithm are reported. The scheme is provably secure with respect to its properties of unforgeability, non-transferability, privacy of signer＇s identity, and non-delegatability.

关键词： designated verifier signature non-delegatability symmetric encryption

Wide Area Analytics for Geographically Distributed Datacenters

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Tsinghua Science and Technology 2016年第2期21卷 125-135页

作者： Siqi Ji Baochun li the Department of Electrical and Computer Engineering University of TorontoToronto M5S 3G4Canada.

Big data analytics, the process of organizing and analyzing data to get useful information, is one of the primary uses of cloud services today. Traditionally, collections of data are stored and processed in a single datacenter. As the volume of data grows at a tremendous rate, it is less efficient for only one datacenter to handle such large volumes of data from a performance point of view. Large cloud service providers are deploying datacenters geographically around the world for better performance and availability. A widely used approach for analytics of gee-distributed data is the centralized approach, which aggregates all the raw data from local datacenters to a central datacenter. However, it has been observed that this approach consumes a significant amount of bandwidth, leading to worse performance. A number of mechanisms have been proposed to achieve optimal performance when data analytics are performed over geo-distributed datacenters. In this paper, we present a survey on the representative mechanisms proposed in the literature for wide area analytics. We discuss basic ideas, present proposed architectures and mechanisms, and discuss several examples to illustrate existing work. We point out the limitations of these mechanisms, give comparisons, and conclude with our thoughts on future research directions.

关键词： big data analytics geo-distributed datacenters

Research on metadata in manufacturing-oriented EAI

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Journal of Systems Engineering and Electronics 2007年第2期18卷 418-426页

作者： Wang Rui li Congxin National Die & Mould CAD Engineering Research Center Shanghai Jiaotong Univ. Shanghai 200030 P. R. China

Enterprise application integration （EAI） focuses on the collaboration and interconnection of various information systems, so the basic problem to be solved is how EAI guarantees that the applications will produce consistent presentation of data, message and transaction. The metadata methodology may give us certain good ideas. First, the metadata description method of manufacturing information resource, transaction process and message delivery is put forward on the basis of operation analysis of manufacturing-oriented EAI, and then the tree-structured XML schema of corresponding object is built and a framework of metadata application in the discrete Manufacturing-Oriented EAI is established. Finally, a practical enterprise information integration system in Shanghai Tobacco Machine Co., Ltd. is presented as an example to show how it functions.

关键词： Discrete manufacturing Enterprise application integration Metadata XML schema.

A Direct Method of Interval Banzhaf Values of Interval Cooperative Games

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Journal of Systems Science and Systems Engineering 2019年第3期28卷 382-391页

作者： Kairong liang Dengfeng li School of Economics and Management Fuzhou UniversityFuzhou 350108China School of Management and Economics University of Electronic Science and Technology of ChinaChengdu 611731China

The goal of this paper is to develop a direct method for computing interval Banzhaf values for a class of interval cooperative *** this method,it is proven that the Banzhaf values of the associated cooperative games of interval cooperative games are monotonic and non-decreasing functions of coalitions,payoffs under weaker coalition monotonicity-like *** the interval Banzhaf values can be explicitly obtained through using only the lower and upper bounds of the coalitions'interval payoffs,*** proposed method does not employ interval subtractions and hereby can effectively avoid the irrational issues such as irreversibility and uncertainty *** prove some important and desirable properties of the interval Banzhaf values and illustrate the applicability and validity of the proposed method with a numerical example.

关键词： Interval cooperative game Banzhaf value group decision cooperative game

Analysis on Pseudo Excitation of Random Vibration for Structure of Time Flight Counter

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Chinese Journal of Mechanical Engineering 2015年第2期28卷 325-330页

作者： WU Qiong li Dapeng Beijing Engineering Technological Research Center of High-efficient & Green CNC Machining Process and Equipment Beihang University

Traditional computing method is inefficient for getting key dynamical parameters of complicated *** Excitation Method（PEM）is an effective method for calculation of random *** to complicated and coupling random vibration in rocket or shuttle launching,the new staging white noise mathematical model is deduced according to the practical launch *** deduced model is applied for PEM to calculate the specific structure of Time of Flight Counter（ToFC）.The responses of power spectral density and the relevant dynamic characteristic parameters of ToFC are obtained in terms of the flight acceptance test *** stiffness of fixture structure,the random vibration experiments are conducted in three directions to compare with the revised *** experimental results show the structure can bear the random vibration caused by launch without any damage and key dynamical parameters of ToFC are *** revised PEM is similar with random vibration experiment in dynamical parameters and responses are proved by comparative *** maximum error is within 9%.The reasons of errors are analyzed to improve reliability of *** research provides an effective method for solutions of computing dynamical characteristic parameters of complicated structure in the process of rocket or shuttle launching.

关键词： pseudo excitation method power spectral density random processes dynamic response vibration

Cobalt-Catalyzed Intermolecular Hydroamination of Unactivated Alkenes Using NFSI as Nitrogen Source

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Chinese Journal of Chemistry 2022年第9期40卷 1066-1072页

作者： Peng-Wei Sun Ze Zhang Xinyao Wang linshan li Yuxin li Zhengming li State Key Laboratory of Elemento-Organic Chemistry Research Institute of Elemento-Organic ChemistryCollege of ChemistryNankai UniversityTianjin 300071China

Cheap metal(Fe,Mn,and Co)-catalyzed hydroamination of alkenes has been an attractive method for synthesis of amines because of biocompatibility of metal,excellent Markovnikov selectivity and ***,most reports are limited to unsaturated nitrogen sources(nitric oxide,azos,azides,cyano,etc.),for which aminated products are very ***,while used widely for fluorinating reaction,N-fluorobenzenesulfonimide(NFsI)as amine source for hydroamination has seldom been *** we developed a cobalt-catalyzed intermolecular hydroamination of unactivated alkenes using NFSl as nitrogen source under mild *** reaction exhibits excellent chemo-and regio-selectivity with no hydrofluorination or linear-selectivity ***,the reaction proceeded with excellent yield even though the amount of Co(salen)catalyst was reduced to 0.2 mol%.Recently,a similar work was also reported by Zhang and coworkers(ref.19).

关键词： Hydroamination Alkenes NFSI Cobalt catalysis Mild conditions