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Particuology 2023年第4期75卷 1-10页

作者： hui Du Haifeng Lu Jie tang Haifeng Liu Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghai200237China

The rapid development of nanotechnology has led to a need to further understand the physical char-acteristics of *** this paper,the flow characteristics of micro-nano alumina particles with different particle sizes were *** FT4 powder rheometer and the PT-X powder tester were used to measure the compression,friction,and dynamic properties of *** compressibility increased significantly as the particle size decreased from 27 μm to 30 *** distribution in the silo was measured and predicted by Janssen's theory,with errors mostly less than 10%.The basic flow energy and the specific energy of the three powders were 4983,1734,and 244 mJ,and 6.80,11.70,and 6.70 mJ/g,respectively,indicating that there was no linear relationship between the change in flowability and particle *** dynamic properties of the powders change from particle-dominated to agglomeration-dominated as the particle size *** conclusion is supported by the results of field emission scanning electron microscopy.

关键词： Micro-nano powders Flow properties Compressibility Frictional properties Pressure distribution

Precipitation and stability of reversed austenite in 9Ni steel

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 587-595页

作者： Yue-hui Yang Qing-wu Cai Di tang hui-bin Wu Research Institute of Metallurgical Engineering University of Science and Technology Beijing Beijing 100083 China

A new method was used to analyze the factors affecting the precipitation of reversed austenite during tempering. The samples were kept at various tempering temperatures for 10 min and their length changes were recorded. Then, the precipitation of reversed austenite which led to the length reduction was shown by thermal expansion curves. The results show that the effects of process parameters on the precipitation of reversed austenite can be determined more accurately by this method than by X-ray diffraction. When the quenching and tempering process is adopted, both the lower quenching temperature and higher tempering temperature can promote the precipitation of reversed austenite during tempering; and when the quenching, lamellarizing, and tempering process is used, intercritical quenching is considered beneficial to the precipitation of reversed austenite in the subsequent tempering because of Ni segregation during holding at the intercritical temperature.

关键词： cryogenic equipment low carbon steel reversed austenite precipitation stability thermal expansion measurement

Two-time-scale Congestion Management Scheme for Microgrid Integrated Distribution Networks

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CSEE Journal of Power and Energy Systems 2023年第4期9卷 1312-1325页

作者： Wei Zhang Yinliang xu Chuheng tang Smart Microgrid and Renewable Technology Research Laboratory Department of Electrical and Computer EngineeringLehigh UniversityBethlehemPAUSA

Microgrids(MGs)with high penetration of dis-tributed generators may cause congestion in the distribution net-work during *** address this issue,this paper proposes a two-time-scale congestion management scheme for multiple MGs integrated distribution ***-ahead hourly-scale dynamic congestion management(DCM)is formulated as a con-strained optimization problem,which can be solved by utilizing the proposed alternating iterative method,with the privacy of both the distribution network and MGs being *** sub-hourly-scale contract energy tracking aims at fully utilizing the controllable resources of the MGs to minimize the difference of the contract and actual exchanged energy between the MG and distribution *** coordination of the proposed two timescales of management schemes,the MGs integrated distribution networks can operate economically while avoiding the probable congestion predicament with high penetration of renewable *** studies with a i3-bus system MGs integrated distribution network demonstrated this proposed approach is effective to manage the congestion problem in the distribution network,while the energy tracking approach can improve the welfare of the MGs engaged in energy contracts ***-Alternating giterativemethod,congestion management,microgrids,renewable energy integration.

关键词： Alternatinggiterativemethod congestion management microgrids renewable energy integration.

A Joint Density Function in the Renewal Risk Model

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Communications in Mathematical Research 2013年第1期29卷 88-96页

作者： xu Huai tang Ling Wang De-hui School of Mathematics Anhui University Department of mathematics Anhui Institute of Architecture and Industry

In this paper, we consider a general expression for Ф（u, x, y）, the joint density function of the surplus prior to ruin and the deficit at ruin when the initial surplus is u. In the renewal risk model, this density function is expressed in terms of the corresponding density function when the initial surplus is O. In the compound Poisson risk process with phase-type claim size, we derive an explicit expression for Ф（u, x, y）. Finally, we give a numerical example to illustrate the application of these results.

关键词： deficit at ruin surplus prior to ruin phase-type distribution renewal risk model maximal aggregate loss

Multilayer ANN indoor location system with area division in WLAN environment

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Journal of Systems Engineering and Electronics 2010年第5期21卷 914-926页

作者： Mu Zhou Yubin xu Li tang School of Electronics and Information Engineering Harbin Institute of Technology Harbin 150001 P. R. China

An indoor location system based on multilayer artificial neural network（ANN） with area division is *** characteristics of recorded signal strength（RSS）,or signal to noise ratio（SNR） from each available access points（APs）,are utilized to establish the radio map in the off-line *** in the on-line phase,the two or three dimensional coordinates of mobile terminals（MTs） are estimated according to the similarity between the new recorded RSS or SNR and fingerprints pre-stored in radio *** the feed-forward ANN with three layers is sufficient to describe any nonlinear mapping relationship between inputs and outputs with finite discontinuous points,the efficient inputs for better training performances are difficult to be determined because of complex and dynamic indoor ***,the discussion of distance relativity for different signal characteristics and optimal strategies for multi-mode phenomenon avoidance is *** also,the feasibility and effectiveness of this method are verified based on the experimental comparison with normal ANN without area division,K-nearest neighbor（KNN） and probability methods in typical office environment.

关键词： indoor location artificial neural network multilayer structure multi-mode relativity.

Cryptography on twisted Edwards curves over local fields

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Science China(Information Sciences) 2015年第1期58卷 150-164页

作者： tang ChunMing xu MaoZhi QI YanFeng School of Mathematics and Information China West Normal University Laboratory of Mathematics and Applied Mathematics School of Mathematical SciencesPeking University School of Science Hangzhou Dianzi University

Twisted Edwards curves over finite fields have attracted great interest for their efficient and unified addition formula. In this paper, we consider twisted Edwards curves over local fields and introduce a cryptosystem based on quotient groups of twisted Edwards curves over local fields. From the study of formal groups of twisted Edwards curves and twisted Edwards curves over local fields, we give the choice of cryptographic *** element in these groups can be uniformly represented by two n digit p-adic numbers, whereas an element in the elliptic curves in Weierstrass form over local fields is represented by a 3n-2 digit p-adic number and a4n-3 digit p-adic number. In the cryptography on elliptic curves in Weierstrass form over local fields, five cases for different input point pairs in computing points addition have to be considered and sometimes points have to be lifted. In the cryptography on twisted Edwards curves over local fields, the addition formula is simple,unified, and complete, which is efficient, does not need lifting points, and is against the side channel ***, a speedy point multiplication algorithm and some concrete instances are given.

关键词： local fields formal groups elliptic curve cryptography twisted Edwards curves addition law

Research on momentum transfer in simple railgun

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Defence Technology（防务技术） 2019年第5期15卷 735-740页

作者： Yingtao xu Bo tang Baoming Li The National Key Laboratory of Transient Physics Nanjing University of Science and Technology

In this paper,the momentum conservation equation in the longitudinal direction for simple railgun was ***,a three-dimensional model was established and the finite element method was utilized to simulate the *** on the simulation,some results such as the surface force on the electromagnetic field,the electromagnetic force on the conductor in the longitudinal direction were ***,the surface force density on different longitudinal section of railgun was analyzed and discussed in *** results showed that the momentum of the railgun system was conserved when the surface force of the electromagnetic field was ***,large amount of longitudinal force was transmitted to the breech by the electromagnetic field in the form of surface *** exact position and distribution of recoil were related to the current input device.

关键词： Railgun Momentum conservation Recoil Surface force

Selective and Sensitive Fluorescent Chemosensors for Cu2＋ Ion Based upon Bis-1,8-naphthalimide Dyads

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Chinese Journal of Chemistry 2012年第2期30卷 267-272页

作者： Dai,huiling xu,hui Laboratory of Pharmaceutical Design&Synthesis College of ScienceNorthwest Agrieulture&Forestry UniversityYanglingShaanxi 712100China

A series of new fluorescent chemosensors 5a--5e, composed of two aminonaphthalimide fluorophores and 2,6-bis（（N-aminoalkyl）aminocarboxy）pyridines, were prepared, characterized, and their fluorescent properties to- wards heavy and transition metal （HTM） ions were investigated. Chemosensors 5e--Se exhibited high selectivity and sensitivity for Cu2＋ ion over other HTM ions with fluorescent quenching （green to colourless）. It clearly demonstrated that the length of the linkers （diamines） between the aminonaphthalimides and 2,6-dicarboxypyridine of 5a--Se was very important for their sensitivity and selectivity for Cu2~ ion over other HTM ions.

关键词： fluorescence sensors 1,8-naphthalimide metal ion selectivity

Survival Conditions of Folding in Different Depth During Orogenesis-Deformation in Texas Creek and Chester Dome, USA

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Acta Geologica Sinica(English Edition) 2014年第1期88卷 103-112页

作者： CAO hui xu Cuiping State Key Laboratory for Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences School of Earth and Environmental Sciences James Cook University

A succession of 5 FIA trends（foliation intersection or inflection axes in porphyroblasts） preserved in high temperature-low pressure regime PreCambrian rocks in the Texas Creek, Arkansas River region reflected by the fold axial plane traces and schistosity data in this region. Similar fold axial plane trace data measured in Palaeozoic rocks in Chester Dome, Vermont, which is high temperature to medium pressure regime, only preserve the effects of the youngest FIAs of the all 5 FIA sets that obtained in this region. The other three FIA sets have no equivalent fold axial planes. This difference from shallow to deeper orogenic regimes reflects decreasing competency at greater pressure with collapse and unfolding of earlier formed folds. The greater overlying load of rocks has tended to flatten all but the very largest early-formed structures, preserving only those folds that were more recently developed.

关键词： orogenesis fold axial plane foliation intersection or inflection axes gravitational collapse porphyroblast

ON SPECTRAL METHODS FOR VOLTERRA INTEGRAL EQUATIONS AND THE CONVERGENCE ANALYSIS

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Journal of Computational Mathematics 2008年第6期26卷 825-837页

作者： Tao tang Xiang xu Jin Cheng Department of Mathematics Hong Kong Baptist University Kowloon Tong Hong Kong China School of Mathematics Fudan University Shanghai 200433 China

The main purpose of this work is to provide a novel numerical approach for the Volterra integral equations based on a spectral approach. A Legendre-collocation method is proposed to solve the Volterra integral equations of the second kind. We provide a rigorous error analysis for the proposed method, which indicates that the numerical errors decay exponentially provided that the kernel function and the source function are sufficiently smooth. Numerical results confirm the theoretical prediction of the exponential rate of convergence. The result in this work seems to be the first successful spectral approach （with theoretical justification） for the Volterra type equations.

关键词： Legendre-spectral method Second kind Volterra integral equations Convergence analysis.