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Science China(Information Sciences) 2020年第6期63卷 97-104页

作者： Dachuan WU Yasha YI Yuxiao ZHANG Integrated Nano Optoelectronics Laboratory Department of Electrical and Computer Engineering University of Michigan Energy Institute University of Michigan

Photonic-based reservoir computing(RC) systems have attracted significant attention. Integrated and purely passive systems are compatible with complementary metal-oxide-semiconductor devices,but are limited by the lack of non-linear components. This study consists of two parts: firstly, a review on the published integrated and passive RC system is presented. The review focuses on the structural configuration(rather than the mathematical model) of the neural network; secondly, a new approach for achieving an integrated and passive photonic RC system is introduced and discussed. This approach employs a mode combiner in front of the reservoir to achieve an extra non-linearity in a purely passive device. Moreover,the approach is numerically investigated, and an XOR(exclusive or) task is used to test the device, and the result shows that the new approach satisfies the requirement of an RC system.

关键词： reservoir computing integrated photonics neural network non-linearity

Intensity and composition-dependent sign reversal of non-linearity in TiO_2/CeO_2 nanocomposites

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Chinese Physics B 2014年第3期23卷 298-302页

作者： S.Divya V.P.N.Nampoori P.Radhakrishnan A.Mujeeb International School of Photonics Cochin University of Science and Technology

CeO2/TiO2 composite nanoparticles with different Ce/Ti molar ratios have been successfully synthesized via sol-gel method. It was found that the band gap of the nanocomposite is tunable by varying Ce/Ti content. The nonlinear response of the sample was studied by using the nanosecond laser pulses from a Q switched Nd：Yag laser employing the Z-scan method. Open aperture Z-scan experiment revealed that with the increase in the CeO2 amount in the nanocomposite, the non-linearity of the composite increases, and it was assumed that this could be due to the modification of TiO2 dipole symmetry by the addition of CeO2. Closed aperture Z-scan experiment showed that when the CeO2 amount increases, positive nonlinear refraction decreases, and this could be attributed to the increase in the two photon absorption which subsequently suppresses the nonlinear refraction.

关键词： sol-gel method non-linearity Z-scan experiment reversesaturation absorption curve

Numerical Modelling of Seismic Site Effects Incorporating non-linearity and Groundwater Level Changes

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Journal of Earth Science 2010年第6期21卷 931-940页

作者： Dominik Ehret Joachim Rohn Dieter Hannich Carlos Grandas Gerhard Huber Department of Applied Geology University of Erlangen-Nuremberg Department of Applied Geology University (TH) of Karlsruhe Institute of Soil and Rock Mechanics University (TH) of Karlsruhe

In the past decades, the necessity for detailed earthquake microzonation studies was recognized worldwide. Therefore, different approaches were established and applied. Unfortunately, the majority of these approaches are not based on pre-existing field data but require extensive seismic measurements and investigations. Furthermore, these approaches incorporate non-linearity inadequately and cannot take groundwater level changes into account. For this purpose, notably numerical models are most suitable. These models require a good knowledge of the local geological conditions （especially of the uppermost unconsolidated units）, information about the geotechnical parameters of these units, and a hydrogeological model of the investigated area. Most of this information can be obtained from geotechnical investigations and surveys that have already been carried out in most densely populated areas. In a case study for Bucharest City, non-linear analyses were performed using software that is based on the visco-hypoplastic constitutive law. The results indicate that groundwater level changes have an important influence on duration and amplitude of ground response and thus should be considered for seismic microzonation studies. This approach ean be used to display site effects and to identify different microzones taking different earthquake magnitudes and groundwater levels into account.

关键词： microzonation site effect visco-hypoplasticity non-linearity Bucharest Romania.

An in situ Digital Background Calibration Algorithm for Multi-Channel R-βR Ladder DACs

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Journal of Electronic Science and Technology 2022年第1期20卷 43-54页

作者： Liang-Jian Lyu Qing-Zhen Wang Ze-Peng Huang Xing Wu the in situ Devices Center School of Communication and Electronic EngineeringEast China Normal UniversityShanghai 200241

The R-2R resistor ladder is one of the best topologies for implementing compact-sized digital-to-analog converter(DAC)arrays in implantable neuro-stimulators.However,it has a limited resolution and considerable inter-channel variation due to component mismatches.To avoid losing analog information,we present sub-radix-2 DAC implemented by the R-βR resistor ladder in this paper.The digital successive approximation register(DSAR)algorithm corrects the transfer function of DACs based on their actual bit weights.Furthermore,a low-cost in situ adaptive bit-weight calibration(ABC)algorithm drives the analog output error between two DACs to zero by adjusting their bit weights automatically.The simulation results show that the proposed algorithm can calibrate the non-linear transfer function of each DAC and the gain error among multiple channels in the background.

关键词： Digital calibration digital-to-analog converter gain error in situ mismatch non-linearity resistor ladder

The Quantitative Instability of non-linearity System and the Particularity of Information

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Engineering Sciences 2005年第4期 88-93页

作者： OuYang Shoucheng~1, Wei Ming~2, Yuan Dongsheng~1, Wang Zengwu~1(1. Chengdu University of Information Technology 610041,China 2. Key laboratory of Mesoscale Severe Weather, Ministry of Education, Nanjing University 210093,P.R. China)

The present paper tries to discuss the quantity instability in the non-linearity dynamics equations without the limit of the stability in the dynamics equations. The result shows that the quantity instability of non-linearity can be deducted to the turning transformation in the curvature space. “The dynamics of varying acceleration" is not the issue of inertia system in science of the time. The particularity as information cannot limit the quantity instability with the quantity stability in inertia system. The particular information does have the significant meaning related to the turning transformation in evolution, in which each problem of non-linearity or matter evolution can go out of the inertia system by means of “kill three birds with one stone".

关键词： non-linearity quantity instability particularity information evolution curvature space

Preparation and characterization of layered low-voltage ZnO varistors

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Journal of Semiconductors 2009年第3期30卷 19-22页

作者：王立惠甘国友孙加林严继康 Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology China nonferrous Metal Mining(Group) Co. Ltd.

Double-layered, low-voltage ZnO varistors have been fabricated by feeding two kinds of ZnO powders into a die using dry extrusion molding. Compared with ZnO varistors fabricated by the conventional route, the layered ZnO varistors have larger non-linear coefficients, lower breakdown electric fields, and lower leakage current densities. The improvement in electrical performance of the layered low-voltage ZnO varistors is attributed to the asymmetric band structure at grain boundary between the two layers.

关键词： layered ZnO varistor non-linearity electrical properties

UNBALANCE RESPONSE AND TOUCH-RUBBING THRESHOLD SPEED OF ROTOR SUBJECTED TO nonLINEAR MAGNETIC FORCES

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Chinese Journal of Mechanical Engineering 2008年第2期21卷 1-4页

作者： JING Minqing LI Zixin LUO Min YU Lie College of Mechanical Engineering Xi＇an Jiaotong University Xi＇an 710049 China

Because of the effect of unbalance excitation and nonlinear magnetic force, the large vibration of the rotor supported by active magnetic bearing（AMB） will go beyond the radial gap of the bearing, even causing mechanical touch-rubbing when the system works at an operational speed closer to the critical speed. In order to investigate this problem, the linear model and nonlinear model of the single mass symmetric rigid rotor system supported by AMB are established respectively and the corresponding transfer functions of close-loop system are given. To pass through the numerical calculation by using MATLAB/Simulink, the effect of both the unbalance response and threshold speed of touch-rubbing of the system subjected to nonlinear magnetic forces and nonlinear output current of power amplifier are studied. Furthermore, threshold speed of touch-rubbing of the rotor-bearing system is defined and the results of numerical simulation are presented. Finally, based on above studies, two methods of increasing the touch-rubbing threshold speed are discussed.

关键词： Active magnetic bearing （AMB） Vibration non-linearity Touch-rubbing speed

Dynamics and control designs for internal thermally coupled distillation columns with different purities,Part 1:Open loop dynamic behaviors

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Progress in Natural Science:Materials International 2006年第5期16卷 346-351页

作者： ZHU Yu, LIU Xinggao and CHU Jian National Laboratory of Industrial Control Technology, Department of Control Science and Engineering, Zhejiang University, Hangzhou 310027, China National Laboratory of Industrial Control Technology Department of Control Science and Engineering Zhejiang University Hangzhou 310027 China

The open loop dynamic behaviors of internal thermally coupled distillation column with four different purities (low-, moderate-, high- and very high-purity) are studied. These dynamic behaviors are characterized by strong asymmetric non-linearity, high sensitivity to operation conditions change and distinct inverse response. With the increase of purity, these dynamic behaviors are intensified and become more complex, which easily lead to the mismatch between linear model and plant and also change the relationship between manipulated and controlled variables.

关键词： thermal coupling inverse response non-linearity high purity asymmetric behavior.

Numerical Simulation of non-Linear Wave Propagation in Waters of Mildly Varying Topography with Complicated Boundary

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China Ocean Engineering 2001年第1期16卷 37-52页

作者：张洪生丁平兴洪广文曹振轶 State Key Laboratory of Estuarine and Coastal Research East China Normal University Coastal and Ocean Engineering Research Institute Hohai University

In this paper, the characteristics of different forms of mild slope equations for non-linear wave are analyzed, and new non-linear theoretic models for wave propagation are presented, with non-linear terms added to the mild slope equations for non-stationary linear waves and dissipative effects considered. Numerical simulation models are developed of non-linear wave propagation for waters of mildly varying topography with complicated boundary, and the effects are studied of different non-linear corrections on calculation results of extended mild slope equations. Systematical numerical simulation tests show that the present models can effectively reflect non-linear effects.

关键词： non-linearity mild slope equations complicated boundary numerical simulation

nonLINEAR NATURAL FREQUENCY OF SHALLOW CONICAL SHELLS WITH VARIABLE THICKNESS

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Applied Mathematics and Mechanics(English Edition) 2005年第3期26卷 277-282页

作者：王新志韩明君赵永刚叶开沅 School of Sciences Lanzhou University of Technology Lanzhou 730050 P.R.China School of Physics Lanzhou University Lanzhou 730000 P.R.China

The nonlinear dynamical variation equation and compatible equation of the shallow conical shell with variable thickness are obtained by the theory of nonlinear dynamical variation equation and compatible equation of the circular thin plate with variable thickness. Assuming the thin film tension is composed of two items. The compatible equation is transformed into two independent equations. Selecting the maximum amplitude in the center of the shallow conical shells with variable thickness as the perturbation parameter, the variation equation and the differential equation are transformed into linear expression by theory of perturbation variation method. The nonlinear natural frequency of shallow conical shells with circular bottom and variable thickness under the fixed boundary conditions is solved. In the first approximate equation, the linear natural frequency of shallow conical shells with variable thickness is obtained. In the third approximate equation, the nonlinear natural frequency of it is obtained. The figures of the characteristic curves of the natural frequency varying with stationary loads, large amplitude, and variable thickness coefficient are plotted. A valuable reference is given for dynamic engineering.

关键词： variable thickness natural frequency non-linearity perturbation variation method