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A high-frequency a high-power GaN HEMT was analyzed using our full band Cellular Monte Carlo (CMC) simulator, in order to extract small signal parameters and figures of merit, and to correlate them to carrier dynamics and distribution inside the device. A complete RF and DC characterization of the device was performed using experimental data to calibrate the few adjustable parameters of the simulator. Then, gate-related capacitances, such as C_g, C_gd, and C_gs, were directly and indirectly extracted combining small-signal analysis and DC characterization.

In this paper, we propose a phase-locked loop (PLL) with dual PFDs and a modified loop filter in which advantages of both PFDs can be combined and the trade-off between acquisition behavior and locked behavior can be achieved. By operating the appropriate PFD connected to the well-adjusted charge pump and regulating the loop bandwidth to input frequency ratio with an input divider and a modified loop filter, an unlimited error detection range, a high frequency operation, a reduced dead zone and a higher speed lock-up time can be achieved. The proposed PLL structure is designed using 1.5 μm CMOS technology with 5 V supply voltage.

In this paper, a high-frequency AC-link DC–AC converter is presented with detailed analysis. This converter is used as an interface between a dc power source and a grid. The studied converter is a universal power converter which consists of two bridges separated by an AC-link; each bridge is connected to a source or it feeds a load. The link of this converter contains a parallel pair inductance-capacitor. The inductance is used to stock/supply energy and for the link capacitor, it allows to perform soft switching during turning on/turning off of the switches. The studied converter has considerable advantages compared to the other topologies. Its fundamental properties are, especially, the compactness, reliability and efficiency which it ensures. Also, it guarantees longer lifetime and the possibility to transfer power in the two power flow directions. In this talk, the principles of the ac-link inverter operation are clearly explained in this paper. Simulation results, under MATLAB/SIMULINK, are shown to validate the correct operation and the efficiency of the proposed converter topology. The control algorithm is, also, experimentally implemented using a dSPACE 1104 control board.

This paper presents a new circuit structure of a multi-mode active filter, using only 16 transistors and 2 grounded capacitors in carbon nanotube field-effect transistor (CNFET) technology which is biased at $\pm 0.5$V supply. The proposed multi-input, single-output (MISO) filter has the capability of working as low-pass, band-pass, high-pass, band-stop and all-pass filters in all the operating modes (voltage, current, transconductance and transresistance). In addition, the quality factor ($Q$) parameter can be tuned electronically independent of the center frequency (${\omega }_0$). The HSPICE simulation results show that the proposed filter consumes only 971$\mu$W at 1GHz center frequency, assuming $C_1=C_2=0.1$pF and the nanotube pitch parameter of ($S=20$ nm) and the chiral vector of (22,0), while the number of nanotubes is considered as $N=16$ for all the transistors. Moreover, the main circuit performances such as the center frequency and the power consumption of the circuit vary by 5.4% and 11.6%, respectively, for the standard temperature variation.

The aim of this paper is to develop a forecasting method with global interval input and output for interval-valued financial time series by combining the VAR$(p)$ process, the volatility information and neural network, namely VAR-NN. To reflect the volatility information, four types of interval-valued data volatility information from both the relative and absolute perspectives are constructed. Furthermore, the neural network is combined to produce the parameters. The developed forecasting model is finally applied to the highest and lowest hourly prices of the Shanghai Composite Index prediction. Numerical study shows the feasibility and validity of the developed improved VAR model.

The vibrations in blood pumps were often caused by high speed, suspension structure, viscoelastic implantation environment and other factors in practical application. Red blood cell (RBC) was modeled using a nonlinear spring network model. The immersed boundary-lattice Boltzmann method (IB-LBM) was used to investigate the impact of high-frequency vibration boundary on RBC. To confirm the RBC model, the simulation results of RBC stretching were compared with experimental results. We examined the force acting on RBC membrane nodes; moreover, we determined whether RBC energy was affected by different frequencies, amplitudes, and vibration models of the boundary. Furthermore, we examined whether RBC energy was affected by the distance between the top and bottom boundaries. The energy of RBCs in shear flow disturbed by the vibration boundary was also investigated. The results indicate that larger amplitude (A_m), frequency (F_r), and opposite vibration velocity of top and bottom boundary produced a larger force that acted on RBC membrane nodes and larger energy changes in RBCs. The vibration boundary may cause turbulence and alter RBC energy. When the blood pump was designed and optimized, the vibration frequency and amplitude of the blood pump body and impeller should be reduced, the phase of the blood pump body and impeller vibration velocity should be close. To alleviate the free energy of RBCs and to reduce RBC injury in the blood pump, the distance between RBCs and the boundary should not be less than 20$\mu$m.

We consider the Cauchy problem for plate equations with rotational inertia and frictional damping terms. We derive asymptotic profiles of the solution in $L^2$-sense as $t\to \infty$ in the case when the initial data have high and low regularity, respectively. Especially, in the low regularity case of the initial data one encounters the regularity-loss structure of the solutions, and the analysis is more delicate. We employ the so-called Fourier splitting method combined with the explicit formula of the solution (high-frequency estimates) and the method due to [R. Ikehata, Asymptotic profiles for wave equations with strong damping, J. Differential Equations257 (2014) 2159–2177.] (low-frequency estimates). In this paper, we will introduce a new threshold $l^{\ast }:=n/2-1$ on the regularity of the initial data that divides the property of the corresponding solution to our problem into two parts: one is wave-like, and the other is parabolic-like.

The anisotropic spindle-like Fe₃O₄ hybrid nanocomposites blended with multi-wall carbon nanotubes (MWCNTs) have been prepared to function as an ideal lightweight candidate for electromagnetic (EM) wave absorption with decent performance in high frequency. The microstructure, morphology, magnetic properties, charge-transfer behavior and EM wave absorbing performance have been characterized by powder X-ray diffractometer, transmission electron microscope, vibrating sample magnetometer, Raman spectrometer and vector network analyzer, respectively. A maximum reflection loss reaches around $-$40dB with 5% MWCNTs loading density. Compared with the monomer Fe₃O₄, the complex permittivity and permeability of the Fe₃O₄–MWCNTs nanocomposites are kept in balance, achieving a better impedance matching with a larger dielectric loss and magnetic loss. The optimization may be attributed to the synergistic effect between spindle-like Fe₃O₄ nanoparticles and MWCNTs. Moreover, the EM microwave absorbing performance can be optimized by tuning the Fe₃O₄–MWCNTs mass ratio and layer thickness of the samples, indicating promising application prospects for outstanding performance EM attenuation materials in high frequency.