NONLINEAR CHARACTERIZATION OF CONCURRENT DUAL-BAND RF POWER AMPLIFIERS

In this paper, the synchronous concurrent dual-band RF signal is used to drive the RF Power Amplifier (PA). The nonlinear characterization of a concurrent dual-band RF PA is discussed while two band signals in the dual-band are modulated by CDMA2000 and WCDMA signals. When the two band signals in the dual-band of the PA are modulated with the same signals, it is found that the nonlinearity of the PA can be expressed by any of the two corresponding baseband data. On the other hand, when the two band signals in the dual-band of the PA are modulated with two different signals, the PA nonlinearity cannot be characterized by any of the two corresponding baseband data. In this case, its nonlinearity has to be denoted by a composite signals consisting of the two baseband signals. Consequently, the requirements for the speed of the A/D converter can be largely reduced. The experimental results with CDMA2000 and WCDMA signals demonstrate the speed of the A/D converter required is only 30 M Sample Per Second (SaPS), but it will be at least 70 M SaPS for the conventional method.

Characterization and identification towards dynamic-based electrical modeling of lithium-ion batteries

Lithium-ion batteries are widely recognized as a crucial enabling technology for the advancement of electric vehicles and energy storage systems in the grid.The design of battery state estimation and control algorithms in battery management systems is usually based on battery models,which interpret crucial battery dynamics through the utilization of mathematical functions.Therefore,the investigation of battery dynamics with the purpose of battery system identification has garnered considerable attention in the realm of battery research.Characterization methods in terms of linear and nonlinear response of lithium-ion batteries have emerged as a prominent area of study in this field.This review has undertaken an analysis and discussion of characterization methods,with a particular focus on the motivation of battery system identification.Specifically,this work encompasses the incorporation of frequency domain nonlinear characterization methods and dynamics-based battery electrical models.The aim of this study is to establish a connection between the characterization and identification of battery systems for researchers and engineers specialized in the field of batteries,with the intention of promoting the advancement of efficient battery technology for real-world applications.

Nonlinear characterization of magnetorheological elastomer-based smart device for structural seismic mitigation

Magnetorheological elastomer(MRE)has been demonstrated to be effective in structural vibration control because of controllable stiffness and damping properties with the effect of external magnetic fields.To achieve a high performance of MRE device-based vibration control,a robust and accurate model is necessary to describe nonlinear dynamics of MRE device.This article aims at realising this target via nonlinear modeling of an innovative MRE device,i.e.MRE vibration isolator.First,the field-dependent properties of MRE isolator were analysed based on experimental data of the isolator in various dynamic tests.Then,a phenomenal model was developed to account for these unique characteristics of MREbased device.Moreover,an improved PSO algorithm was designed to estimate model parameters.Based on identification results,a generalised model was proposed to clarify the field-dependent properties of the isolator due to varied currents,which was then validated by random and earthquake-excited test data.Based on the proposed model,a frequency control strategy was designed for semi-active control of MRE devices-incorporated smart structure for vibration suppression.Finally,using a three-storey frame model and four benchmark earthquakes,a numerical study was conducted to validate the performance of control strategy based on the generalised current-dependent model with satisfactory results.

ON THE EXISTENCE AND NODAL CHARACTER OF SOLUTIONS OF SINGULAR NONLINEAR BOUNDARY VALUE PROBLEMS

In this paper we prove the existence of k-node solution of singular nonlinear boundary value problems for each k is-an-element-of N union {0}.

ON THE EXISTENCE AND NODAL CHARACTER OF THE SOLUTIONS OF SINGULAR NONLINEAR BOUNDARY VALUE PROBLEMS

1. Introduction We consider the singular nonlinear boundary value problem where l=v+3/v-1,l+1 is the critical exponent of the embedding of weighted Sobolev space Wt21,2（O, +∞） into Lt2q（O, ∞）, v>2. When v=N-1 we can get the radial solutions of problem where 2*=2N/N-2 is the critical exponent of the Sobolev embedding H1（Rn）→LQ（RN）. Kurtz has discussed the existence of κ-node solution of （1.1）, （1.2） for each κ∈N U{0} when the growth rate of |u|l-1u+f（u） is lower then |u|v+3/v-1 i.e.

Nonlinear optical characterization of single β-barium-borate nanocrystals using second-harmonic confocal microscopy

The confocal microscopy technique was applied for nonlinear optical characterization of single β-barium-borate（β-BBO） nanocrystals. The experimental setup allows measurements of the laser polarization-selective secondharmonic（SH） generation, and the results can be used to determine the nanocrystals＇ c-axis orientation, as well as to obtain information about their second-order susceptibility χ^（2）. The dependence of the SH signal on the laser polarization allowed the discrimination of individual particles from aggregates. The data were fitted using a model that takes into account the BBO properties and the experimental setup characteristics considering（i） the electrostatic approximation,（ii） the effects of the microscope objective used to focus the light on the sample in an epi-geometry configuration, and（iii） the symmetry of χ^（2） for the β-BBO nanocrystals. A signal at the third-harmonic frequency was also detected, but it was too weak to be studied in detail.