Function Of Input Voltage Research Articles

Characterization testing of the Northrop Grumman MiniCoolerPlus (MCP)

Northrop Grumman Space Park (NGSP) introduced the Mini Cooler Plus (MCP) to their family of pulse tube cryocoolers in 2019 [1] and presented the details of its TRL6 qualification testing in 2022 [2]. The thermal mechanical unit (TMU) of the MCP is an extension of space-qualified pulse tube coolers, all of which are designed to provide a long life (ten-plus years) of delivering low-mass, high-cooling capacity for hyperspectral and infrared imaging payloads in tactical airborne and space applications. The cooler is of modular split configuration allowing flexibility in the compressor (wave generator) and cold head placements to meet the available envelope of packaging constraints. The cold head assembly can be oriented at any position relative to the compressor assembly, and the transfer line (length and shape) can be customized to individual applications. The TMU (thermo-mechanical unit) weighs less than 3kg and can lift 1.5 W at 45 K or 11 W at 110K with 150 W electrical input at 300 K reject. The thermal performance has been characterized as a function of input voltage and as a function of cold tip load and temperature at variety of heat sink temperatures of -20C, 0C, +20C and +40C. Functional testing of the MCP was performed to higher input powers and MCP performance data versus operating conditions were collected. An analytical expression for cold tip load (Qc), impedance (Z) and power factor (PF) as a function of reject temperature (Trej), cold tip temperature (Tc), frequency (f), and input power (Pac) were generated. These tests were repeated with third party control electronics. All results will be presented here.

Stability investigations based on two-port describing functions

Purpose Stability of a nonlinear, tuned amplifier has been investigated based on the describing function method. On stability, this paper means global asymptotic stability. The tuned amplifier comprises a saturated amplifying device with feedback and two resonators, at the input and the output. Describing function method here means introduction of the two-port describing functions. Design/methodology/approach Describing function method is applied, extended for two ports. Results from complex analysis and matrix algebra are heavily used. The two resonators have identical resonant frequency and bandwidth. Instability is represented by non-vanishing output perturbation for zero-input perturbation. Applying a simple transistor model with saturation and feedback, stability is analyzed in the form of output voltage as a function of input voltage. Findings Two-port scattering and admittance describing functions have been introduced. At a certain input voltage amplitude, instability appears in the form of unwanted sidebands, then at a higher input voltage, instability disappears, in good agreement with experiments. The hand calculated stability limits are in good agreement with the computer analysis. Originality/value The paper is based on an early publication of the author (Baranyi and Ladvánszky, 1984). Here, the full material is presented, explained step by step, extended and revised. All neglections that were earlier made in the author’s paper have been avoided here. This paper has significant tutorial value as well.

Spatial accumulation of phase difference in spoof plasmon based Mach–Zehnder Interferometer

An active beam steering structure comprising the spoof surface plasmon polariton (SSPP) waveguide is presented. The proposed structure consists of two stages: the two arms structure as a Mach–Zehnder interferometer (MZI), and free space propagation stage. The SSPP waveguide includes periodic grooves, which are filled with a thin layer of doped semiconductor like GaAs. By applying electric voltage at the electrodes on top of the waveguide, the depletion layer thickness and the effective refractive index of the dielectric inside the grooves can be changed. The effective refractive index of the dielectric inside the groove is derived analytically and the phase change of the propagation wave along the single sided SSPP waveguide is calculated as a function of input voltage. The relation between the input signal and the angle of maximum radiation of output beam is investigated and the linearity is improved. We have shown that the MZI beam steering section has the capability to bend the electromagnetic beam about 42 degrees. At the end, we presented an application of the proposed beam steering device as a spatially accumulated phase difference structure that can be utilized in devices such as digital-to-analog converter (DAC).

Enhanced Response Time of Electrowetting Lenses with Shaped Input Voltage Functions.

Adaptive optical lenses based on the electrowetting principle are being rapidly implemented in many applications, such as microscopy, remote sensing, displays, and optical communication. To characterize the response of these electrowetting lenses, the dependence upon direct current (DC) driving voltage functions was investigated in a low-viscosity liquid system. Cylindrical lenses with inner diameters of 2.45 and 3.95 mm were used to characterize the dynamic behavior of the liquids under DC voltage electrowetting actuation. With the increase of the rise time of the input exponential driving voltage, the originally underdamped system response can be damped, enabling a smooth response from the lens. We experimentally determined the optimal rise times for the fastest response from the lenses. We have also performed numerical simulations of the lens actuation with input exponential driving voltage to understand the variation in the dynamics of the liquid-liquid interface with various input rise times. We further enhanced the response time of the devices by shaping the input voltage function with multiple exponential rise times. For the 3.95 mm inner diameter lens, we achieved a response time improvement of 29% when compared to the fastest response obtained using single-exponential driving voltage. The technique shows great promise for applications that require fast response times.

Time function triple Langmuir probe measurements in low frequency pulsed DC discharge plasma

This study investigated the temporal profiles of electron temperature and number density in rectified DC air discharge generated with a 50 Hz step-up transformer. An in-house built triple Langmuir probe and circuitry were used to diagnose the plasma parameters as a function of input voltage and filling gas pressure. A tungsten metal wire capable of withstanding the high temperatures was used as probe tip material. The temporal profiles revealed an increase in electron temperature with input voltage in the range of 380 to 450 V, whereas, an inverse relation between number density and input voltage was evident in the given work. The observed trend in the plasma parameters was absolutely reversed in case of the filling gas pressure. The electron temperature linearly decreased with an increase in pressure from 1 to 4 mbar, whereas a linear increase in number density with pressure was seen in the temporal profiles. Finally, it was concluded that the results for the tested plasma parameters were consistent and the in-house built probe functioned well in DC discharge for the used range of voltage and filling pressure.

A thermal network model for induction motors of hermetic reciprocating compressors

This paper describes a simulation model for small reciprocating compressors with emphasis on the electrical motor modelling. Heat transfer is solved through algebraic equations derived from lumped thermal energy balances applied to the compressor components. Thermal conductances between the motor components are characterized via a thermal network model. The single-phase induction motor is modelled via an equivalent circuit, allowing predictions for the motor performance and distributed losses. The predicted temperature distribution is used to evaluate the stator and rotor windings resistances. The thermal and electric models are solved in a coupled manner with a model for the compression cycle. Predictions of temperature distribution, motor efficiency, as well as isentropic and volumetric efficiencies, are compared with experimental data at different operating conditions. The model is then applied to analyse the motor temperature as a function of input voltage and stator wire diameter.

Modelling of ions for seeding technique to electrify the atmosphere

Abstract There are number of ways in which weak electrification can affect the microphysics of clouds, with consequences for cloud lifetime, radiative properties, and precipitation efficiency. Kauffman [2011] suggested ions produced by direct current generators will add to and enhance the catalysing effects that cosmic ray ions are now known to produce in among other things, lowering nucleation barriers, stimulating charged particle growth and stability and increasing the scavenging rate in clouds. Thus to electrify the atmosphere ions can be generated artificially in abundance along with large electric field. Ions can be generated by the corona effect using Atmospheric electrifiers (a device used to generate negative ions) which makes use of corona discharge phenomenon to charge the air particles. Exact assessment of electric field and charge density distributions and the flow dynamics inside the electrifiers is essential to understand the particle behaviour inside the electrifiers. In this paper, a novel model of governing equations to evaluate the space charge density, electric field intensity and velocity of ionized airflow is suggested as a function of applied voltage. The Poisson and charge conservation equations are derived and hence can be used to estimate the electric field and charge density distributions. Navier stokes equation can be used to get the velocity of ionized airflow because of electric force on the air. Simulation is carried out to validate the proposed model and verify that velocity is function of input voltage and is proportional to it.

Analysis, design and performance of a soft‐switching single‐phase inverter

A soft-switching pulse-width modulation (PWM) single-phase inverter using a voltage clamp soft-switching step-up/down dc link is proposed in this study. The proposed voltage clamp soft-switching step-up/down DC link not only provides the switches in the section of conventional PWM buck inverter operate at zero-voltage-switching (ZVS), but it has a step-up/down input voltage function and the switches in itself also operate at ZVS. Thus, except for the switch in the section of ZVS-PWM auxiliary circuit, all power semiconductor devices in proposed inverter operate at ZVS turn-on and turn-off. The switch in the section of ZVS-PWM auxiliary circuit operates at zero-current-switching (ZCS) turn-on and turn-off. Besides operating at constant frequency, the proposed inverter has no voltage stress and current stress on the main switch compared to the hard switching inverter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis and experimental results of the proposed soft-switching inverter, rated 1 kW and operated at 40 kHz, are provided in this study to verify the performance.

Fluorescence response of human HER2+ cancer- and MCF-12F normal cells to 200 MHz ultrasound microbeam stimulation: A preliminary study of membrane permeability variation

Targeted mechanical cell stimulation has been extensively studied for a better understanding of its effect on cellular mechanotransduction signaling pathways and structures by utilizing a variety of mechanical sources. In this work, an ultrasound-driven single cell stimulation method is thus proposed, and a preliminary study is carried out by comparing the fluorescence intensities representing a change in cell membrane permeability between MDA-MB-435 human HER2+ cancer cells (∼40–50μm in diameter) and MCF-12F normal cells (∼50–60μm) in the presence of ultrasound. A 200MHz single element zinc oxide (ZnO) transducer is employed to generate ultrasound microbeam (UM) whose beamwidth and depth of focus are 9.5 and 60μm, comparable to typical cell size. The cells in tetramethyl rhodamine methyl ester (TMRM) are interrogated with 200MHz sinusoidal bursts. The number of cycles per burst is 5 and the pulse repetition frequency (PRF) is 1kHz. The temporal variation of fluorescence intensity in each cell is measured as a function of input voltage to the transducer (16, 32, and 47V), and its corresponding fluorescence images are obtained via a confocal microscope. A systematic method for visualizing UM’s focus by adding Rhodamine B to the immersion medium is also proposed to enhance the precision in aiming the beam at an individual cell.Both types of cells exhibit a decrease in the intensity upon UM irradiation. In particular, normal cells show more fluorescence reduction (down to 0.7 in normalized intensity) than cancer cells (∼0.9) under the same excitation condition of the transducer. With UM being turned off, the normalized intensity level in normal cells is slowly increased to 1.1. The cell images taken before and after UM exposure indicate that the intensity reduction is more pronounced in those cells after exposure. Hence the results show the potential of UM as a non-invasive in vitro stimulation tool for facilitating targeted drug delivery and gene transfection as well as for studying cellular mechanotransduction.

An Equivalent Circuit Model for Semi-parallel Plate Electrostatic Torsion Mirror

An equivalent circuit model for the semi-parallel plate electrostatic torsion mirror has been developed based on the electrical circuit simulator. An analytical model for the electrostatic torque has been translated into a nonlinear dependent current source as a function of input voltages that interpret the drive voltages and the mirror angle. A use of the suspension width as a fitting parameter explained well the experimental results of frequency response and the mirror's static deflection.

Frequency representations of one‐port networks

PurposeAnalysis of harmonics propagation in power systems requires information about models of non‐linear loads which are the main source of harmonics. The purpose of the paper is to present a method of parameter determination of non‐linear loads.Design/methodology/approachA method of parameter determination of a model has been described in the article. This method has been developed assuming that mathematical description of a non‐linear load is known. In order to obtain a harmonic representation of this model for one‐phase loads the theory of harmonic balance method has been used.FindingsParameters of the current or voltage controlled sources can be expressed as a function of any number of voltage or current harmonics. In the case under consideration the network input current is a function of input voltage and its derivatives. Thus, contrary non‐linear element with inertialess characteristics, the first harmonic of the current depends not only on amplitude but also on frequency of the voltage across terminals of one‐ports.Originality/valueThe method presented in the paper enables relatively simple determination of frequency parameters of non‐linear models of one‐port networks.

디스크형 압전 변압기의 전기적 특성

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is <TEX>$Pb[(Mn_{1/3}Sb_{2/3})_{_0.05}Zr_{0.475}Ti_{0.475}]O_3$</TEX> with mechanical quality factor of 1600, electromechanical coupling coefficient <TEX>$59\%$</TEX>, and piezoelectric constant <TEX>$d_{33}$</TEX> 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize output voltage, step-down ratio as a function of electrode area with the input remained constant, and power, efficiency as a function of input voltage, and temperature-dependent electric characteristics were evaluated. The sample APT1 showed the best properties. The highest admittance, effective electromechanical coupling coefficient and an appropriate mechanical quality factor were obtained at the sample with the input/output area ratio of 1:1.5 at the common electrode, and the condition of 20 <TEX>$V_{rms}$</TEX>, <TEX>$50\;\Omega$</TEX> made the maximum efficiency of <TEX>$95\%$</TEX>. The temperature was increased by 14.7'E as the input voltage was increased for <TEX>$50\;V_{rms},\;50\;\Omega$</TEX>.

MIXED CONVECTION IN A RECTANGULAR CAVITY WITH A PULSATING HEATED ELECTRONIC COMPONENT

ABSTRACT Combined free and forced convection in a rectangular cavity with a pulsating heat-dissipating electronic component is studied numerically. The cavity walls are adiabatic and the bottom component is cooled by an external throughflow of air. The present study simulates a practical situation in which periodic heat is generated in an electronic component as a result of its periodic input voltage. The effects of important parameters such as Rayleigh number, Strouhal number, and input voltage function on temperature field and heat transfer are investigated. The results indicate that, by increasing the Rayleigh number, the component heat transfer rate increases, and better cooling is achieved. The average Nusselt number and maximum temperature fluctuation amplitude depend strongly on the pulsation frequency. The results also show that, in comparison to the sinusoidal case, the step-input pulsation produces fluctuations with higher amplitude for maximum component temperature and average Nusselt number.

Optical device design with arbitrary output intensity as a function of input Voltage

We show that the designs for optical digital signal processing can be used to construct a device that gives an arbitrary function I(V), where I is the output signal intensity and V is the input voltage. This is done by applying the same voltage V to several electrodes in the system, and does not require changing the input optical frequency. This device will have applications to modulator linearization and correction for amplifier distortion. We present a numerical simulation of the device. We study the device as a function of wavelength and voltage.

Experimental investigation of an ion-drag pump-assisted capillary loop

An ion-drag pump was constructed and calibrated to determine the available pumping pressure as a function of input voltage for various working fluids. The experimental results were then compared with an analytical model and found to predict the ion-drag pump performance to within ±15%. Using this information, an analytical model capable of predicting the performance enhancement of an ion-drag pump-assisted capillary loop was also developed and compared with the values obtained from experimental tests conducted on a thermal test loop. Although the analytical model slightly overpredicted the performance enhancement resulting from the ion-drag pump, the predicted trends were similar to those obtained from the experimental program. These trends included decreased thermal test loop performance with increased evaporator/condenser elevation difference, increased performance (due to increased operating temperature), and an increase in performance ranging from 20 to 100%, due to the addition of a two-stage ion-drag pump. The performance enhancement of the thermal test loop was verified at various operating temperatures and evaporator/condenser elevation differences. Nomenclature d = diameter g = gravitational acceleration h = evaporator/condenser height difference / = current L = length Me = merit number P — pressure Q = heat transport capacity r = radius V = voltage 8 = emitter/collector electrode spacing e = dielectric constant 77 = efficiency @ = wetting angle A = latent heat jit = viscosity v = volumetric flow rate p = density a = surface tension (/> = angle of inclination Subscripts c = capillary EHD = electrohydrody namic g = gravitational / = liquid v = vapor 0 = charge

Light-emitting transistor based on real-space transfer: electrical and optical properties

The charge injection transistor is implemented in InGaAs/InAlAs/InGaAs heterostructure material, grown by molecular beam epitaxy. A complementary collector of p-type conductivity is used for the first time. The real-space transfer of hot electrons leads to a luminescence signal proportional to the injection current. The radiative efficiency is significantly enhanced by a double-heterostructure design of the collector active region, which confines the injected minority carriers. The internal quantum efficiency of the light-emitting transistor is comparable to that of light-emitting diodes. Due to peculiar symmetry of real-space transfer, the optical output signal follows an exclusive-OR function of input voltages. Functional logic operation of the device is demonstrated at room temperature.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Light emitting charge injection transistor with p-type collector

We report the first realization of a charge injection transistor with a complementary collector. The device is implemented using InGaAs/InAlAs/InGaAs heterostructure material grown by molecular beam epitaxy. Real space transfer of hot electrons into the p-type collector leads to a luminescence signal arising from the recombination of the injected electrons with holes in the collector active region. The observed on/off ratio in the emitted light power is more than 104 and obeys an exclusive OR function of input voltages. The estimated internal quantum efficiency is as high as 90%.

On the observation of chaotic and related phenomena

Abstract Because of the fact that the waveform of the response function of a nonlinear oscillatory system may (as is shown here for an L-C circuit with a nonlinear capacitor) be strongly sensitive to changes in the waveform of the input function, especially for low losses in the system, criteria for the ideality of the waveform of the input function are required, for investigation of chaotic and related phenomena in such a system. The slight imprecision in the input waveform which is due to the nonzero output impedence of the practical input voltage function generators and due to the property of the nonlinear load to generate high harmonic currents in a wide range of frequencies, influencing the generator's output function, may be very important.

BJT&amp;#8212;MOSFET transconductance comparisons

Through normalization it becomes possible to construct curves of considerable generality for comparing the transconductance properties of BJT's and MOSFET's. Three comparisons are given. The first presents transconductance as a function of output current; the second, transconductance divided by output current as a function of input voltage; and the third, transconductance as a function of input voltage. The BJT advantage increases rapidly with output current and (or) input voltage. The curves approach each other under extremely low-level conditions, but appreciable deviations from the simple theory upon which the present analysis is based also occur in the low-level regime--especially deviations connected with subthreshold conduction in the MOSFET, as well as excess conduction near but above threshold. For these reasons, the moderate-level portions of the simple-theory comparisons are the most meaningful. Recently developed subthreshold analysis is also used in the second comparison.

A Function Generator for Dynamic Control of a Plasma

A function generator is constructed to generate voltage as any given function of input voltage. The generator approximates any function including a nonmonotonic one by quantizing it into 11 steps. It has fast response (less than 100 nsec), good frequency characteristic (up to 10 MHz), and is easy to construct. It is to be used with a V-to-f converter in a feedback loop of rf confinement of a plasma, where the most favorable frequency is given as a nonlinear function of plasma density.