Inkjet printed electronics for multifunctional composite structure

Copper nano-ink with a drop-on-demand (DOD) piezoelectric inkjet printing method was introduced. The printed electrodes were thermally sintered to ensure high-quality electrical and mechanical performances. To check the reliability of the printed electrodes on a polymer layer, resistance changes were measured under static loading. The electrodes with various widths and thicknesses were used to find the optimal dimensions. A multifunctional composite laminate which can harvest and store a solar energy was fabricated using printed electrodes. An amorphous silicon solar cell and a thin film solid state lithium-ion battery were adhesively joined and electrically connected to a thin flexible printed circuit board (PCB). Then, the passive components such as resistor and diode were electrically connected to the printed circuit board by silver pasting. The integrated PCB was co-cured with a carbon/epoxy composite laminate by the vacuum bag molding process in an autoclave. The structural and functional performance of the final energy harvesting/storage composite laminate was tested under mechanical loading.     

The New Developed Components Tests for 1 MJ Capacitor Power Supply System in Wuhan High Magnetic Field Facility

A new 1 MJ, 25 kV, 40 kA pulsed capacitor power supply system for the Wuhan High Magnetic Field Facility (WHMFF) has been achieved. The desire for 70 or higher tesla magnetic field to support a lot of scientific researches based on it is just now beginning to be realized. The system consists of charger, capacitor bank, polarity changing switches, protective inductor, thyristor switch, crowbar, dump circuit and so on. In this paper, a series of tests for the new developed components such as high energy pulsed capacitor with 160 μF/25 kV/10 kA/10 ms/30% voltage reversal, thyristor switch (25 kV, 40 kA, 10 ms), polarity changing switch and ZnO linearly resistor disc for crowbar are introduced. The results show that all of new components are good or better than the old 1 MJ power supply system.     

A microcontroller-based quasi-balanced bridge for the measurementof L, C and R

A microcontroller-based quasi-balanced bridge for the measurement of parameters of an inductor or a capacitor is described. The unknown element (inductor or capacitor) in series with a resistor forms one-half of an ac bridge, while a multiplying digital-to-analog converter (MDAC) serves as the other half. The bridge is brought into two independent quasi-balanced conditions in succession by the microcontroller through the MDAC. The parameters of the unknown element are shown to be functions of the settings of the MDAC at the two quasi balanced conditions. The relevant expressions for these parameters are evaluated by the microcontroller and the results displayed in appropriate display fields. The proposed scheme was implemented using an Intel 8751 microcontroller and tested. The readings obtained on the prototype were compared to those obtained with a commercial LCR meter. Employing an MDAC of basic accuracy ±0.2%, over the frequency range of 100-1000 Hz, an overall uncertainty in measurement of ±0.7% for the prototype was achieved     

A novel method of measurement of L and C

A novel method of measurement of component values of inductors and capacitors is described. The technique is independent of the voltage across or current through the unknown inductor or capacitor, as it involves only a set of phase measurements. The unknown capacitor/inductor is connected in series with a known standard resistance and this series circuit is excited by a source of required voltage and frequency. The resistive and reactive parts of the unknown component are measured by measuring the phase displacement between the three voltages, namely, voltage applied, voltage across the inductor/capacitor and the voltage across standard resistance. The proposed scheme is verified both by simulation as well as by building a prototype. The relationship between the range of the measurement and obtainable accuracy level is established. For the prototype built, with a one decade span in the measurement range, a commercially acceptable accuracy of ±2.0% was achieved. However, this accuracy can be further improved by suitable circuit modifications     

Simple models for dynamic hysteresis which add frequency-dependentlosses to static models

The broadening of magnetic hysteresis with increasing frequency of excitation may be represented in an electrical equivalent circuit by placing a resistor in parallel with an inductor whose core is the magnetic material represented by a static hysteresis model. This broadening can be controlled as an arbitrary function of frequency by changing the resistance with frequency. This, in turn, may be accomplished by using a parallel set of linear resistors, each placed in series with a bandpass filter, in place of a single resistor. This technique is illustrated by a simulation of both fast pulse excitations and moderate frequency sinusoidal excitations for 3C81 ferrite material using an equivalent circuit containing just three resistive parallel branches along with the static hysteresis model of Jiles and Atherton     

A modified circuit topology for inductive pulsed power supply based on HTSPPTs

High temperature superconducting pulsed power transformer (HTSPPT) provides an efficient method for inductive energy storage and current multiplication. The primary inductor of HTSPPT used for energy storage is made of high temperature superconducting coils, and the secondary inductor used for current pulse generation is made of normal conductor coils. In the initial circuit, the secondary inductor generates current pulse by switching out the coupled primary superconducting inductor. However, during the switching period, the leakage flux caused by imperfect coupling and the sudden change in primary current induce a voltage across the opening switch which exceeds the affordability of modern solid-state switches. In previous studies, a half-cycle oscillatory discharge circuit is proposed to mitigate these problems by using a capacitor to recapture the energy in the leakage flux and to slow down the turnoff of current in the primary. However, there are still some problems should be settled. For example, the output pulse cannot be adjusted, the residual energy cannot be recovered and the capacitor branch circuit may have an impact on the charging process. In the paper, a modified discharge circuit topology is introduced to solve these problems. A multi-module system comprising of several HTSPPTs charging in series connection and discharging in parallel is also designed and simulated. This system can be used to power an electromagnetic emission device.     

Electrical properties of electrodeposited polyaniline nanotubes

The electrical properties of polyaniline nanotubes-aluminum like Schottky diode are described. Polyaniline nanotubes (PANI) were deposited on aluminum thin films using the polarographic technique. The nanotubes were characterized by scanning electron microscopy (SEM) and UV-Vis absorption spectra. The electrical properties of the heterojunction PANI-Al were examined. The current density–voltage (J × V) profile has shown a behavior typical of Schottky diode, with ideality factor (n) of 6.76 and ϕ _b of 0.70 eV. Impedance spectroscopy data apparently shows that the resistance dominated the AC behavior of the PANI-Al system. The equivalent circuit is composed from a resistor in series with a parallel resistor–capacitor circuit. The results indicate that polyaniline nanotubes may be interesting to the development of electro-optical devices with 2D structure.     

脉冲偏压下电弧离子镀等离子体负载的等效电路模型及其定量表征

为了解决电弧离子镀(AIP)工艺中脉冲偏压电源与AIP等离子体负载间的匹配问题,结合脉冲偏压下AIP工艺实验,运用等离子体鞘层理论、电路理论和仿真模拟技术,得到AIP等离子体负载本质上是由鞘层引起的容性负载,在电路中可以等效为电容和电阻相并联的单元;根据AIP等离子体鞘层演化的特性,将AIP等离子体负载的等效电容表征为与时间无关而只与脉冲偏压幅度和等离子体相关参数有关的量,AIP等离子体负载的等效电阻,可以在直流偏压下通过测量与脉冲偏压幅值对应的AIP等离子体负载电流来确定.经验证,本文建立的AIP等离子体负载的等效电路模型及其定量表征是有效性的.     

Equivalent circuit model of semiconductor nanowire diode by SPICE

An equivalent circuit model of nanowire diodes is introduced. Because nanowire diodes inevitably involve a metal-semiconductor-metal structure, they consist of two metal-semiconductor contacts and one resistor in between these contacts. Our equivalent circuit consists of two Schottky diodes and one resistor. The current through the reverse-biased Schottky diode is calculated from the thermionic field emission (TFE) theory and that of the forward-biased Schottky diode is obtained from the classical thermionic emission (TE) equation. Our model is integrated into the conventional circuit simulator SPICE by a sub-circuit with TFE and TE routines. The results simulated with our model by SPICE are in good agreement with various, previously reported experimental results.     

A Differential Capacitor Circuit for Very High and Low Dielectric Q-Factor Measurement at High Frequencies

This paper presents an electronic circuit system that is capable of measuringdielectric Q-factor Qx (= 1/tan ?) ranging from 0.01-10 at measuring frequencies 100 kHz-30 MHz, and from 10-105 at 1-300 MHz. For measurement of very high loss materials, a tripartite differential capacitor is used as a variable resistor to substitute for low Rx, and for measurement of very low loss materials, an ordinary differential capacitor connected in series with two fixed deposited fim resistors is used to substitute for high unknown resistance Rx. An important characteristic of the circuit is its capability of measuring capacitance and resistance of high loss materials accurately.     

Experimental characterization of on-chip inductor and capacitor interconnect: part I. Series case

Detailed experimental investigations described here show the overall characteristics of on-chip inductor and capacitor serial interconnects (L--Cs) on silicon substrates. Using a new equivalent circuit model and the measured S parameters obtained by deembedding techniques, we examine and compare a single inductor, single capacitor, and two sets of series L--Cs. Agreement between the measured and simulated S parameters is excellent. At low frequency, the first resonant frequency f/sub res/ of series L--Cs can be easily determined by f/sub res/=(2/spl pi//spl radic/(LC))/sup -1/, while at high frequency, parasitic parameter effects of both the substrate and the metal strips on f/sub res/ of the L--Cs circuit must be considered.     

Measurement of AM to PM conversion in medium wave AM transmitter

A method for measuring AM (amplitude modulation) signal distortion caused by AM to PM (phase modulation) conversion at the output of an AM radio transmitter is presented. A novel type of measuring instrument is also presented for testing the phase distortion which may occur in an AM radio transmitter when an AM modulation signal is applied. The down-converted AM signal is first divided into the inphase and orthogonal-phase components, and these signals are processed by an operational circuit to obtain phase distortion, which is the angle between the orthogonal-phase and inphase components. A phase angle of 10° or more is detected in the prototype version     

Circuit design of an integrable simulated inductor and itsapplications

Gyrator principles are used to design an integrable voltage-controlled simulated inductor with inductance variable from 0.1 to 250000 H or even higher. One of the features of this simulated inductor is that it contains two voltage-controlled current amplifiers with controlling terminals connected in parallel. For a resonant circuit consisting of such a simulated inductor and an external capacitor, the resonant frequency will be linear with the controlling voltage. It can be employed to realize a sine-wave oscillator or filter whose operation frequency is changed linearly with the controlling voltage. In this work a linear voltage-controlled sinusoidal oscillator, which was designed to have an oscillation frequency from several kHz down to 0.01 Hz, is taken as an example to illustrate an application of the simulated inductor. In this case the simulated inductor was made up of discrete components and the oscillator has been employed to provide standard signals for research on differential transformation of physiological spikes in medical science     

A New High-Speed Method of Testing Capacitors

A new high-speed method of determining the capacitance and a quantity which the writers call the pulse series resistance (PSR) of an unknown capacitor is presented. The unknown capacitor is assumed to consist of an ideal capacitor and a series resistor. The test circuit consists of a low-impedance driver, a low-loss coupling capacitor, and a wide-band high-input/low-output impedance video-type amplifier. The unknown capacitor is placed in a negative feedback loop of this amplifier. The input waveform is a trapezoid. The output waveform contains information that is indicative of the capacitance and PSR of the unknown capacitor. The information is obtained by measuring two voltages, one of which is completely independent of the other. Capacitors were measured from approximately 2 pf to 2 ?f with an accuracy of ±5 per cent. The PSR was not available for capacitors less than 100 pF because of test-circuit limitations. The capacitance and PSR of an unknown capacitor could be made available within 500 ?sec with modern voltage-measuring and calculating techniques.     

Suppression of nonlinear composite panel flutter with active/passive hybrid piezoelectric networks using finite element method

For the suppression of nonlinear panel flutter, a new optimal active/passive hybrid control design with piezoceramic actuators is proposed using finite element methods. This approach has the advantages of both active (high performance, feedback action) and passive (stable, low power requirement) systems. Piezoceramic actuators are connected in series with an external voltage source and a passive resonant shunt circuit which consists of an inductor and resistor. The shunt circuit should be tuned correctly to suppress the flutter effectively with less control effort as compared to purely active control. To obtain the best effectiveness, active control gains are simultaneously optimized together with the value of the resistor and inductor through a sequential quadratic programming method. The governing equations of the electromechanically coupled composite panel flutter are derived through an extended Hamilton’s principle, and a finite element discretization is carried out. The adopted aerodynamic theory is based on the quasi-steady first-order piston theory, and the von Kármán nonlinear strain–displacement relation is used. Nonlinear modal equations are obtained through a modal reduction technique. Optimal control design is based on linear modal equations of motion, and numerical simulations are based on nonlinear-coupled modal equations. Using the Newmark integration method, suppression results of a hybrid control and a purely active control are presented in the time domain.     

基于并联电感同步开关控制的振动能量回收方法研究

针对振动能量回收使用的并联电感同步开关(SSHI)控制方法研究中未考虑的控制损耗、储能负载和激励环境等问题,设计了一种基于电流监控、比较器、单片机和双向电子开关的低功耗回收控制电路。单片机通过比较器产生的中断信号控制双向开关适时闭合,成功实现了并联SSHI回收控制电路的功能。以储能装置为负载时,分析了整流电压、振子电容、激励幅值和频率对并联SSHI回收电路控制效果的影响,结果表明该方法在整流电压值较高、振子电容较大、激励频率较高、激励力较小时能够更有效地提高回收效率,为并联SSHI控制方法的应用奠定了一定的理论基础。     

Modeling of charge switching in ferroelectric capacitors

To simulate charge switching in ferroelectric capacitors, a pair of exponential growth and decay currents is mapped to the process of polarization reversal. This is based on the fact that these exponential currents [i.e., i = I(m) e(t/tau) (t < or = 0) and i = I(m) e(-t/tau) (t > or = 0)], are completely specified by two constants I(m) and tau and each accommodates an integral charge Q = I(m) x tau. Equating this charge to the remanent spontaneous polarization allows for the modeling of switching current. For practical circuit simulations for charge switching, this modeling of switching current is simplified to an exponential decay current whose integral charge is set equal to the total reversed spontaneous polarization. This is because an exponential decay current can be conveniently implemented by charging a series resistor and capacitor (RC) circuit with a pulse-voltage source. The voltage transitions of the pulse source are associated with the polarization reversal and can be controlled with a noninverting Schmitt trigger that toggles at the positive and negative coercive voltages of a ferroelectric capacitor. The final circuit model incorporates such electrical and geometrical parameters as capacitance, remanent spontaneous polarization, coercive field, electrode area, and film thickness of a ferroelectric, thin-film capacitor.     

Coupled Dielectric Nanoparticles Manipulating Metamaterials Optical Characteristics

In this paper, we investigate the concept and theory of all-dielectric metapatterned structures that manipulate electric and magnetic optical characteristics. A 3-D array of dielectric particles is designed, where the spheres operate in their magnetic modes and their couplings offer electric modes. An analytical solution for the problem of plane wave scattering by 3-D array of dielectric nanospheres is presented. FW multipole expansion method is applied to express the optical fields in terms of the electric and magnetic dipole modes and the higher order moments. By enforcing the boundary conditions at the surface of each sphere, with the use of the translational addition theorem for vector spherical wave functions, required equations to determine the scattering coefficients are obtained. Novel materials features in optics are demonstrated. Electric and magnetic scattering coefficient resonances around the same frequency band are obtained. It is highlighted how a metapatterned structure constructed from dielectric nanosphere unit cells can provide electric and magnetic modes resulting in backward wave phenomenon. A comprehensive circuit model based on the RLC (resistor, inductor, and capacitor) realization is presented to successfully analyze the scattering performance of a dielectric nanosphere. To better understand the physics of an array of spheres, circuit models for the interactions, and couplings between spheres are also accomplished. The engineered dispersion diagram for a 3-D array of identical highly coupled nanospheres is scrutinized, verifying that the high couplings between spheres can offer the backward wave characteristics.     

Drive to generate digital current for control vertical field in asmall Tokamak

The horizontal position of a small Tokamak plasma has been controlled by a circuit to generate the control vertical field. The circuit must respond quickly to the position signal from a feedback circuit and feed a large current in a short time. We have assembled the circuit to generate a digital current called a drive. The drive includes several units, and each unit is made up of a capacitor, a transistor, a protective resistor and a comparator. We have installed the drive on a small Tokamak, the Hamana-T and obtained satisfactory results. The performance of the drive is described     

Detection of capacitor electrolyte residues with FTIR in failure analysis

Detecting leakage from liquid aluminum electrolytic capacitors is not easy. Typically there is very little evidence of leakage because the electrolyte is volatile and leaves behind only trace residues. Liquid aluminum electrolytic capacitors are known to cause catastrophic failures where there is complete loss of functionality due to a short or open circuit. In the study presented in this paper, printed circuit board assemblies from a test and measurement system used in a clean room environment failed. Two units failed, causing burning in a particular area on the printed circuit board assembly. The failure area included several surface mount liquid aluminum electrolytic capacitors, and several others were mounted very close to the burnt region. A study was initiated to evaluate the cause of failure. Careful optical inspection revealed some residues on the outer side of the rubber seals of two of the electrolytic capacitors. Through using Fourier transform infrared analysis and a process of experimentation and analysis, it was determined that the residues were produced by liquid electrolyte that leaked out of the capacitor at some point in the field. The leaked electrolyte that came out of the capacitor was believed to be the cause of failure that led to the burning of the printed circuit board assembly.