Characteristics of electric breakdown in repeated frequency pulse with microcavity effect

Reprint of: Effect of pulse parameter change on a-SiCN diaphragms for environmental cells fabricated by magnetic-field- and pulsed-plasma-enhanced chemical vapor deposition

This paper presents a new method for the design of control laws for systems with on-off nonlinear actuators. The new methodology improves the design of control laws for pulse-modulated systems by allowing the use of continuous-time multi-inputlmultioutput design procedures. Discrete-time state feedback control gains are developed from the of continuous-time feedback gains, based on a geometric series approximation, to closely match the states of the closed-loop hybrid system to those of the original designed closed-loop continuous-time system at each sampling instant. A delay is then incorporated into a pulse-width modulator design to closely match the states of the modulated system to those of the discrete-time pulse-amplitude modulated system. The delay time is improved from previous work to provide a close match between the states for pulse durations of all sizes, in effect matching the states of the pulse-width modulated system to those of the closed-loop continuous-time system. The new control law design is applied to the problem of attitude control of the Space Shuttle Orbiter with the Hubble Space Telescope deployed on its remote manipulator. * Senior Member Technical Staff. Member A I M . t Professor, Electrical Engineering. Member AIAA. tt Aerospace Engineer. Member AIAA. Copyright O 1995 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Many paradigms are available for the synthesis of control laws for continuous-time systems, and though many methods also exist for developing discrete-time or digital controllers, it is often desirable to design a control law for the continuous-time plant. It is often more direct to determine the control specifications in the continuous-time or frequency domain. Also, direct digital control law design has difficulty in predetermining the hybrid control specifications and ignores inter sampling effects. Yet, these continuoustime control laws are generally implemented via discrete-time computer control, requiring that a discrete-time control, equivalent to the continuous-time control, be developed. The process of developing discrete-time control laws that provide closed-loop performance of the hybrid system equivalent to the performance of the designed closed-loop continuoustime system is known as redesign. Several techniques have been developed to digitally redesign continuous-time feedback controllers[l] ,[2] ,[3]. Unfortunately, the principal applied for the design of discrete-time control laws, i.e., that the amplitude of the control signal can take any finite value, which is why discrete-time control is often referred to as pulse-amplitude control (PAM), is not valid for all computer controlled systems. Systems that utilize onoff control devices, such as the reaction jet or electronic relay, can only provide a single finite value of control. To provide control with these types of actuator, either complex non-linear algorithms[4] must be developed or the control must be applied by modulating the pulse width, the pulse frequency or both the pulse width and frequency. These modulation techniques, in particular pulse-width modulation (PWM), allow the design of linear control laws to control non-linear systems. Although methods exist for the design of linear control laws for pulse width modulation systems[5], they still

High-voltage electric field-driven jet deposition technology is a novel high resolution micro scale 3D printing method. In this paper, a novel micro 3D printing method is proposed to fabricate wax micro-structures. The mechanism of the Taylor cone generation and droplet eject deposition was analyzed, and a high-voltage electric field-driven jet printing experimental system was developed based on the principle of forming. The effects of process parameters, such as pulse voltages, gas pressures, pulse width, pulse frequency, and movement velocity, on wax printing were investigated. The experimental results show that the increasing of pulse width and duration of pulse high voltage increased at the same pulse frequency, resulting in the micro-droplet diameter being increased. The deposited droplet underwent a process of spreading, shrinking, and solidifying. The local remelting and bonding were acquired between the contact surfaces of the adjacent deposited droplets. According to the experiment results, a horizontal line and a vertical micro-column were fabricated by adjusting the process parameters; their size deviation was controlled within 2%. This research shows that it is feasible to fabricate the micro-scale wax structure using high-voltage electric field-driven jet deposition technology.

Polypropylene (PP) has been considered as an alternation to cross-linked polyethylene (XLPE) using as the high voltage direct current (HVDC) cable insulation material due to its no crosslinking process and environment friendly characteristics. During the operation, repetitive pulse voltage may generate in HVDC cable system and the challenge of the low temperature environment may occur. This paper compares the tree characteristics of PP and XLPE with the pulse voltage of 12 kV and 400 Hz under low temperature. Furthermore, the influence of pulse amplitude and frequency on the electrical trees of PP under low temperature is investigated. The frequencies of pulse voltage were 400, 800 and 1200 Hz and the pulse amplitudes were 12 and 15 kV. The experimental temperature from 30 to -196 °C was applied in the test. The results show that compared with the XLPE, the electrical tree is more difficult to be generated in the PP. The growth rate and fractal dimension of tree in the PP are smaller than these in the XLPE with the same treeing time. The low temperature, pulse frequency and amplitude have an influence on the treeing process. It is obtained that the growth of electrical tree is resisted under the low temperature. The higher pulse frequency accelerates the tree propagation process. The higher amplitude accelerates the tree growth rate and fractal dimension at -30 and -196 °C. However, the tree propagation process is not accelerated by the higher amplitude at -90 °C.

Plasma electron density and temperature were characterized in a continuous flowing gas-liquid film reactor with argon carrier gas by time-resolved optical emission spectroscopy. The plasma parameters were studied as a function of time for varying pulse widths and frequencies. Pulse frequency was varied between 1 and 10 kHz at 16 kV (input voltage) and 40 ns (pulse width) using an Eagle Harbor Technologies, Inc. (EHT) power supply and 5–100 kHz using an Airity Technologies, LLC (AT) power supply. The pulse width was varied between 40 and 200 ns at 16 kV, 2 kHz with the EHT power supply. Optimal frequencies of 5 and 20 kHz were observed for peak electron density with EHT and AT power supplies, respectively. The peak electron density increased with increasing pulse width between 40 and 200 ns using the EHT power supply. Hydrogen peroxide exiting the reactor in the liquid phase increased with discharge power irrespective of the power supply or pulse parameters. Mineralization of 12.5, 50, and 200 ppm perfluorooctanoic acid (PFOA) dissolved in DI water to fluoride (F−) correlated to the peak electron density. Glycerol, a liquid-phase hydroxyl radical scavenger, depleted hydrogen peroxide but did not affect PFOA mineralization. CO, a gas-phase hydroxyl radical scavenger, led to a reduction in the formation of F− production, suggesting hydroxyl radicals in the gas-liquid film play a necessary, but not singular, role in mineralization of PFOA.

Al-Si alloy at eutectic region as the research object, Electric pulse modification (EPM) were used to achieve simultaneous refinement and modification of eutectic silicon phase, in order to analyze the mechanism of electrical pulse modification to the alloy and analyzed how the EPM affects the solidification structure and the corresponding properties. We get the conclusion by observing the microstructure of the sample, measuring the hardness, calculating the volume fraction and the average size of primary silicon at different pulse frequency and voltage. By using this process the particle size of primary silicon was reduced from 50 µm to a range of 5-20µm and the shape changes from acicular to fine fiber when compared with the conventional casting process. Also, the result of mechanical test showed that the hardness increase from 105HV-156HV with the change in pulse voltage at 700V peak value it therefore increased with 49% and at 1000V decline to 144HV with increased by 37% with homogeneous distribution of eutectic silicon.

This paper analyzes the effects of scaling and measurement conditions on the performance of hybrid organic inorganic perovskite (HOIP) devices having bipolar resistive switching characteristics. Electroforming voltage, SET current, and ON/OFF ratios are found to be area dependent. Linear voltage sweep and pulse voltage characterization showed that parameters such as compliance current, voltage scan rate, pulse width, amplitude, and frequency significantly alter the device switching parameters. The CH3NH3PbI3 memristors fabricated has FORMING, SET, and RESET voltages of 1.18, 0.17, and −0.13 V, respectively, along with an ON/OFF ratio of 1.3 × 103. It has been found that, both the RESET voltage and current significantly increase with scan rate, whereas the ON/OFF ratio increases significantly with compliance current. In case of voltage pulse characterization, the ON/OFF ratio can be enhanced by increasing the pulse amplitude and width. Additionally, the experimental data fitting to a SPICE based analytical model establishes that the HOIP memristor current conduction is dominated by tunneling process in the OFF state and is ohmic in the ON state. Based on the results, the authors arrive at a general protocol that can be used to characterize memristors made of HOIPs and other related materials such that they can operate optimally.

Electric field, accompanying with the magnetic field produced by high current, can generate electro-magnetic force in HVDC system, which enormously affects the treeing process. Electrical tree behavior of silicone rubber (SiR) was investigated by application of magnetic field with repetitive pulse voltage. The samples were made of silicone rubber with a pin-plane electrode system. The inserted needle had a tip radius of 3 μm and the pin-plane distance was 2 mm. The rise time and fall time of the repetitive pulse voltage were 100 and 120 μs respectively. The pulse frequency was 200 Hz, while the pulse amplitude ranging from 6 to 12 kV was applied. The magnetic flux density (B) of the magnetic field was 100, 200 and 400 mT respectively. The results were presented from experimental investigations in order to characterize electrical tree as a function of amplitude and polarities of the applied pulse voltage. The patterns of electrical tree, tree length, accumulated damage and tree breakdown characteristics were studied. It is revealed that both the pulse amplitude and polarity have a significant impact on electrical tree growth characteristics of silicone rubber. Results show that the pulse amplitude plays the leading role in electrical tree initiation, propagation and breakdown processes. Compared with the positive pulse, it is suggested that the larger tree accumulated damage is more easily to occur with the negative pulse. It also has been found that tree structure is greatly dependent on the B of magnetic field. Results show that magnetic field promotes tree growth and accelerates the treeing process.

In this work, the ferroelectric thin-film transistor (Fe-TFT) with polycrystalline-silicon (poly-Si) channel and HfZrO x gate dielectric is fabricated to study the characteristics of non-volatile memory (NVM). Significant threshold voltage (V TH) modulation can be achieved with low pulse voltages less than ±3.5 V and pulse widths within 1 μs. In order to achieve the NVM characteristics of low voltage and high speed operation, the impact of the program/erase (PRG/ERS) pulse voltage (V PRG/V ERS) and pulse width on endurance is a critical consideration. In the study of the pulse width effect on endurance, it can be observed that the V TH in PRG-state exhibits the wake-up effect at both short and long pulse widths. In addition, with the increase of pulse width, the V TH in the PRG-state exhibits significant fatigue effect and subthreshold swing (SS) degradation effect. For V TH in the ERS-state, the increase of the pulse width also exhibits the fatigue effect and the SS degradation effect, which is dominated by the SS degradation effect at long pulse widths. In the study of the pulse voltage effect on endurance, the increase of V PRG shows the imprint effect that the V TH in either PRG- or ERS-state reveals a decreasing trend. When the V ERS increases, the SS of the PRG- and ERS-states is degraded, and the fatigue effect of the PRG-state is enhanced. Moreover, the retention characteristics of poly-Si Fe-TFTs exhibit stable characteristics at both room temperature and 50 °C.

In laser percussion drilling, holes are produced mainly by melt ejection with a series of laser pulses. The circularity of the holes not only depends on various laser-processing parameters but also their interactions that influence the characteristics of melt ejection. In this work a statistical modelling approach was used to study the effects of six processing variables (peak power, pulse width, pulse frequency, number of pulses, assist gas pressure and focal plane position) and their interactions on the hole circularity. Response surface method was used to statistically analyse the process. For each variable five levels were considered and the experiments were conducted based on a Central Composite Design (CCD). The experiments were performed using an optical fibre delivered Nd:YAG laser drilling on mild steel sheets of 2.5 mm thickness. An analysis of variance (ANOVA) was performed to test the significance of the variables at 1% and 7% levels. It was found that pulse width has a significant effect on the hole entrance circularity. Pulse frequency and number of pulses have very little effect on the hole entrance circularity.

In order to study the mechanism of microcrack generation in the process of pulsed laser polishing of zirconia ceramics and the influence of laser polishing process parameters on the surface temperature and surface stress, this paper establishes a finite element computational model of pulsed laser polishing of zirconia ceramics based on the COMSOL Multiphysics multi-physics field simulation software. Firstly, in the process of establishing the finite element model, the temperature field and stress field coupling is used to analyze the temperature field and stress field changes during the laser polishing process, which reveals the microcrack generation mechanism and size characteristics of zirconia ceramics in the process of pulsed laser polishing. Secondly, through parameterized scanning, the variation rules of surface temperature and surface stress were studied under different process parameters of laser power, scanning speed, pulse frequency and pulse width. Finally, the validity of the finite element calculation model is verified by the pulsed laser polishing zirconia ceramics experiment. The results show that, in a certain energy range, the high-energy laser beam can effectively reduce the surface roughness of the material, and with the increase in the time of laser action on the surface layer of the material, it will cause the temperature and thermal stress of the surface layer of the material to continue to accumulate, and when the stress value exceeds the yield limit of the material, cracks will form in the surface layer of the material; because the laser power, scanning speed, pulse frequency and pulse width are used to affect the laser energy density, and then, the pulse width will be affected by the process parameters of the laser energy density, and thus the surface temperature and thermal stress of the surface layer of the material. Because the laser power, scanning speed, pulse frequency and pulse width all affect the thermal stress on the material surface by influencing the laser energy density acting on the material surface, the laser energy density is the main influencing factor of the dimensional characteristics of the microcracks. In addition, the microcrack width and depth will increase when the laser energy density acting on the material surface layer increases.

The delay time distribution (DTD) of type Ia supernovae (SNe Ia) from star formation is an important clue to reveal the still unknown progenitor system of SNe Ia. Here, we report on a measurement of the SN Ia DTD in a delay time range of $t_{\rm Ia} = $ 0.1-8.0Gyr by using faint variable objects detected in the Subaru/XMM-Newton Deep Survey (SXDS) down to $i'$$\sim$ 25.5. We selected 65 SN candidates showing significant spatial offset from the nuclei of the host galaxies having an old stellar population at $z$$\sim$ 0.4-1.2, out of more than 1000 SXDS variable objects. Although spectroscopic type classification is not available for these, we quantitatively demonstrated that more than $\sim$80% of these should be SNe Ia. The DTD was derived using stellar age estimates of the old galaxies based on 9 band photometries from optical to mid-infrared wavelength. Combined with the observed SN Ia rate in elliptical galaxies at the local universe, the DTD in $t_{\rm Ia}$$\sim$ 0.1-10Gyr is well described by a featureless power-law as $f_{\rm D}$($t_{\rm Ia}$) $\propto$$t_{\rm Ia}^\alpha$ with $\alpha$$\sim$$-$1. The derived DTD is in excellent agreement with a generic prediction of the double-degenerate scenario, giving strong support to this scenario. In the single-degenerate (SD) scenario, although predictions by simple analytic formulations have broad DTD shapes that are similar to the observation, DTD shapes calculated by more detailed binary population synthesis tend to have strong peaks at characteristic time scales, which do not fit the observation. This result thus indicates either that the SD channel is not the major contributor to SNe Ia in an old stellar population, or that an improvement of binary population synthesis theory is required. Various sources of systematic uncertainties were examined and tested, but our main conclusions were not affected significantly.

Voltage pulse and current pulse test of phase change memory (PCM) device is realized by computer controlling pulse generator, digital source meter, current pulse generating circuit, switching circuit and other hardware devices. The PCM device test includes several modules of the relationship between current and voltage, voltage and current, resistance and voltage pulse width or height, resistance and current pulse width or height, and fatigue characteristics. In these test modules, the automatic switching system achieves the automatic switching between voltage pulse and current pulse test. The automatic switching system of voltage pulse and current pulse test can not only achieve the automation of engineering testing, but also can reduce the noise interference.

Signal correlator with programmable variable time delay based on optical coherent transients

Summary form only given. We have been studying a decomposition of an organic compound in water by pulsed power discharge in a water droplets spray. Since sprayed water has a large reaction area and the discharge of gas phase generates uniformly a lot of streamers that generate OH radicals, ozone, high-energy electrons and radiate ultraviolet, decomposition efficiency increases by using this method. In this experiment, the dependence of the decomposition ratio of brilliant blue FCF on treatment time was compared with that of ozone oxidization. The treated brilliant blue FCF solution was 1 liter with concentration of 20 mg/L. An experimental setup consisted of a pulsed power generator and a discharge reactor. A pulsed high voltage was generated by a pulse transformer. The discharge reactor has coaxial electrodes that consist of a stainless wire of 0.28 mm diameter for applying pulse voltages and a cylindrical stainless mesh of 40 mm inner diameter and 300mm length for a ground electrode. The typical pulsed voltage and discharging current at a charging voltage of 25 kV were 25 kV with the pulse width of 70 ns (FWFIM) and 90 A, respectively. A repetition rate of the pulsed voltage was 100 pps. The treated water was sprayed into the reactor by a showerhead. The sprayed water was corrected and circulated into the reactor by a pump continuously. The decomposition ratios were measured by a UV and visible-light absorption spectrometer. A result shows that brilliant blue FCF was decolored by the circulation of 10 minutes.