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In this study, the 10B21 steel was treated by micro-arc oxidation (MAO) in the electrolyte consisting of aluminate and phosphate to enhance its corrosion resistance. The effect of negative voltage on corrosion resistance of the MAO coating obtained has mainly been analyzed through their phase composition, microstructure, interfacial bonding strength, salt spray and electrochemical testing. The result indicates that with negative voltages applied to the MAO coating, Fe-Al transition layers arise between coating layer and matrix. Furthermore, different negative voltages bring forward different α-Al2O3 contents contained in the MAO coatings and when it reaches −100 V, the amount of α-Al2O3 appears as the largest. The surface porosity of the coating was also significantly decreased. In addition, the corrosion current density of the coating is only 3.64 μA·cm−2, which is two orders of magnitude lower than that of the substrate. After 72 h of salt spray corrosion, it is found that the coating substrate is less corroded when the negative voltage of 100 V is applied. Therefore, −100 V has been proven as the optimum performance for improving the corrosion resistance of 10B21 steel.

Triboelectric nanogenerators (TENGs) have attracted many research endeavors as self-powered sensors for force, velocity, and gas detection based on solid-solid or solid-air interactions. Recently, triboelectrification at liquid-solid interfaces also showed intriguing capability in converting physical contacts into electricity. Here, we report a self-powered triboelectric sensor for liquid chemical sensing based on liquid-solid electrification. As a liquid droplet passed across the tribo-negative sensor surface, the induced surface charge balanced with the electrical double layer charge in the liquid droplet. The competition between the double layer charge and surface charge generated characteristic positive and negative voltage spikes, which may serve as a "binary feature" to identify the chemical compound. The sensor showed distinct sensitivity to three amino acids including glycine, lysine and phenylalanine as a function of their concentration. The versatile sensing ability was further demonstrated on several other inorganic and organic chemical compounds dissolved in DI water. This work demonstrated a promising sensing application based on the triboelectrification principle for biofluid sensor development.

Current Transformers (CTs) saturation leads to distortion of current waveform and operational malfunction of protection relays. This paper introduces a practical and simple method to prevent CTs saturation. The method uses a negative voltage feedback and applies it to CT secondary side. The injected voltage opposes the excitation voltage of CT in a manner that the magnetic flux of CT remains almost constant under saturation level for any faults. The method is categorized as a hardware solution, does not need to detect the CT saturation time and works either for digital or non-digital relays. The method is verified in a wide range of simulations and experimental results. The obtained results show that the method is reliable, effective, and accurate.

This paper focuses on the operation of hybrid modular multilevel converter and proposes an effective approach that guarantees the full performance of the converter even in post-fault condition. The main novelty of this paper is utilizing negative arm voltage levels in a way to compensate the missed voltage. After the fault occurrence, the DC component of the arm voltages as well as the DC-link voltage are adjusted based on the fault states to restore the nominal balanced line-to-line voltage in the post-fault condition. In comparison with the previous methods, the proposed method does not add any hardware to the circuit to restore the nominal output voltage. The capacitor voltage of submodules, also, does not increase after fault occurrence. Therefore, the converter can maintain its nominal line-to-line voltage in post-fault condition without extra implementation costs or overdesign requirements. To validate the effectiveness of the proposed method, detailed simulation and experimental results are provided.

In this letter, a reconfigured switched-capacitor converter (SCC) is proposed that is capable of achieving seven negative voltage conversion ratios (VCRs) using only three flying capacitors and min...

Traditional wire electrochemical micro-machining (WEMM) of type-304 stainless steel using dilute hydrochloric acid (HCl) generates a certain amount of insoluble electrolysis product that adheres onto the wire. As the machining process continues, a blackened layer is generated on the wire that hampers the machining process. Herein, a double-pulsed WEMM (DP-WEMM) method is proposed to eliminate this blackened layer, effectively so as indicated by experimental results. An optimal negative voltage is determined as −0.3 V. The slot profile and machining stability obtained with DP-WEMM are considerably better than those with traditional WEMM. For the same machining parameters and feed rate, traditional WEMM with dilute HCl manages a 1.8-mm-long slot until short circuit occurs. By contrast, DP-WEMM is terminated manually after a 5.0-mm-long slot is obtained, there having been no short circuit.

Background Exposure of human lung epithelial cells to the oxidant pollutant ozone (O3) alters cell Cl− currents inducing an outward rectifier effect. Among the various Cl− channels, ClC-2 and ORCC seemed to be involved in this response. Objectives To identify the channel related to O3 induced current changes. Results Down regulating the expression of ORCC and ClC-2 genes and analyzing the membrane current show that the enhancement of the current disappeared when ORCC was silenced. The contribution of ORCC and ClC-2 channels in control and O3 treated cells was obtained by a mathematical approach. Conclusion We suggest that O3 activates ORCC channels and slightly inhibited ClC-2 channels in the negative voltage range. These findings open the possibility of identifying the biomolecular changes induced by O3 allowing a possible pharmacological intervention towards chloride current due to oxidative stress.

A magnetically isolated MOSFET driving circuit based on a driving transformer has been widely used in aerospace secondary power supplies. Based on the analysis of two typical magnetically isolated driving circuits, a new type of driving circuit is proposed. This circuit has the characteristics of zero negative voltage, high reliability, and wide duty cycle operating range. It is very suitable for a new generation of aerospace high-efficiency high-power-density power supply topology, and it has important significance for improving the efficiency of space borne secondary power supplies.

In this article the initiation of a corona discharge from a negatively charged point with a small radius of curvature is investigated experimentally and as a result of modeling. Modeling showed that the periodicity of the discharge current in our model is observed only in the case of adding electron detachment reactions to the plasma-chemical scheme. The reason for the pulse-periodic mode of current flow is the presence of negative O2− ions. It was shown experimentally that the first streamers at a minimum voltage have a ball shape.

Gap electrospinning is a facile technique to produce aligned nanofibers useful for many applications, but its potential has not yet been fully exploited in nature, leading to the fiber length still limited to several tens of centimeters at present. In this work, we report a breakthrough in the production of well-aligned nanofibers with record length and efficiency. Using a suitable poly(vinylidene fluoride) solution and a pair of parallel plates that are substrate-free and negatively connected, we demonstrate the ease of this technique to prepare length-controllable aligned fibers in a wide range (≤125 cm). Because of the crucial roles of both the jet whipping instability that continuously drives the jet to span across the static plates and the negative voltage on the plates that effectively attracts the positively charged jet, the jet can be made to move back and forth over the superlarge gap to form ultralong aligned nanofibers. By introducing a projection method, we also redefine fiber alignment in a broader sense. This work is believed to provide a new insight into the nature of gap electrospinning, which will greatly expand the versatility of this technique to create devices for a myriad of applications.

The present work investigates the OFF-state lateral band-to-band-tunneling (L-BTBT) phenomena in a buried-metal-layer (BML) based junctionless (JL) FET (BML-JL-FET). The impact of BML-workfunction and BML-voltage on the L-BTBT component of the gate-induced-drain leakage (GIDL) is studied via the 2-D TCAD simulations. The nature of Schottky junction formed at the bottom of the semiconductor device layer has also been investigated. We observe that the sufficiently high BML-workfunction, or high BML-workfunction with negative voltage, allows for excessive band bending at the bottom Si/BML interface, resulting in the accumulation of the opposite charge carriers (holes). If BML is not optimized, this accumulated holes contribute adversely to the L-BTBT current component of the device. In addition, the impact of BML acting as a secondary gate on the device characteristics has also been studied.

On-site investigation of PID behavior of PV module has been carried out under typical Malaysian climate. A quantitative degradation measurement process of PV module through EL imaging has been introduced. PID has been observed only for the negative voltage stress in this p-type polycrystalline Si PV module. The negative end PV module degrades 42% due to 9 years field aging under a negative voltage stress from the 240 V string size. While positive end PV module is degraded near about 17% over the same period due to normal field aging. Shunt resistance of negative-end module has been found 75% lower than that of the positive-end module. Module crack propagation is found to be accelerated due to onsite cyclic high voltage stress. PID at higher string size has been estimated from the leakage current of brand new same PV module. The estimated PID of PV module under 600 V stress is 72.84%.

This work reports the design of nano-level starch-gelatin biopolymeric blends incorporated with nano-TiO2 for energy storage applications in areas which need to utilise negative voltages. Six different activated nanoarchitectures were designed, push coated on nickel foam substrates and characterized with FTIR, a Zeta sizer, XRD, TEM, CV, EIS, and GCD techniques for structural, functional and electrochemical properties respectively. The C O C glucosidic linkage, amide A bond, Ti O bond were seen at 1068, 2783, 602 cm−1 to confirm the succesful synthesis of starch-gelatin-TiO2 nanohybrids, while TEM confirmed well dispersed TiO2 NPs dispersed within the crystalline starch nanoparticles and oval shaped nano-gelatin NPs. XRD analysis revealed crystallite sizes to be in the range of 21–98 nm for all nano-architectures, and confirmed the prescence of highly ordered phases suitable for energy storage, after activation. The zeta sizer investigations determined that the samples were nanoparticulates with sizes below 100 nm. The highest specific capacitances obtained at 5 mVs−1 were 237, 246, 349, 686, 691, 808F/g in the three electrodes configuration and 194, 204, 287, 541, 570, 617F/g in the two electrodes configurations for AS-NPs, AG-NPs, ASG-NHs, AS-TiO2 NHs, AG-TiO2-NHs and ASG-TiO2-NHs respectively. When the samples were tested using a three-electrode and two-electrode configuration, the activated starch-gelatin-TiO2 nanohybrid showed the lowest Rct of 0.28 Ω and 0.51 Ω, energy densities of 208.3 and 176.4 Wh/Kg, and power densities of 6213 and 5406 W/Kg. All samples had retention capacities of 86–95%, with the activated starch-gelatin-TiO2 nanohybrid having values of 95% and 92% for the GCD experiments run using three and two electrode configurations. This work demonstrates that biopolymer nanohybrids can be effective electrodes for supercapacitors devices in energy storage applications.

Electrospun nanofibrous scaffolds providing local delivery of vascular endothelial growth factor (VEGF) have distinctive advantages for vascular tissue engineering. However, more than 90% of VEGF were normally released from scaffolds formed by conventional positive-voltage emulsion electrospinning (PVEES) within the initial 3 days. VEGF molecules bear positive charge. In this investigation, emulsion electrospinning using power supplies of different polarities was studied for producing scaffolds bearing specific electric charge. VEGF-containing poly(lactic-co-glycolic acid) scaffolds with initial potential of −87 and −202 V were formed by negative-voltage emulsion electrospinning (NVEES) at −10 and −20 kV, respectively, which enabled steady and sustained release up to 18 days, exhibiting effective modulation for VEGF release. Compared to VEGF-containing scaffolds formed by PVEES, NVEES-formed scaffolds showed superior performance in promoting endothelial cell functions.

This study was aimed to develop of electrostatic precipitator and wet scrubber integration technology for controlling NO x and particulate matter emission from semiconductor manufacturing process. The integration system was consisted of O 3 oxidation, wet scrubber and electrostatic precipitators (EPSs). In O 3 oxidation, NO gas was fully oxidized by O 3 before flow gas was entered through wet scrubber. NO 2 was mostly absorbed by wet scrubber using Na 2 S and NaOH without generating H 2 S. In ESPs, the negative voltage of 15 kV was applied to collection plate, and the particle removal efficiency showed higher than 95%. The practical removal efficiency was higher than theoretical because the practical loading by discharging corona was greater than the theoretical. In addition, the particle removal efficiency was maintained at 95% for 60 min through the water film.

In the previous chapters we saw that both BTI and EM recovery can be activated and accelerated; these unique recovery behaviors can benefit future resilient digital systems if they are instrumented on chip. In this chapter, we discuss a set of circuit blocks that implement the required functionality for achieving accelerated and active self-healing on chip. Examples of such portable circuit IP blocks are negative voltage generators, reconfigurable heaters, wearout-aware power gating, bidirectional-current PDNs, and novel types of BTI and EM sensors. We present design details, functionality, and potential costs of each type of circuit. By implementing all or a subset of these circuit IPs, recovery can be enabled on chip with acceptable hardware costs.

SiC MOSFETs are well known for possessing lower losses compared with silicon MOSFETS or IGBTs. In order to drive them efficiently, suitable drivers must be designed. However, most commercially available drivers and drivers in literature are suitable for only a limited range of SiC MOSFETs due to limitations on the MOSFET's gate voltage ratings. Hence, the drivers do not allow the designer to easily experiment with different SiC MOSFET models. In this paper, a generic SiC gate driver with adjustable positive and negative voltage rail is presented. The performance of the proposed driver is compared with a commercially available driver through experiment and it is shown that the proposed gate driver is able to drive the chosen SiC MOSFET more efficiently. Accepted version

DC-DC converters are commonly used in power-conserving applications, like battery-operated equipment to regulate to a lower voltage, boost an input voltage or invert it to create a negative voltage. Efficiency is an important DC-DC converter characteristic as it may achieve efficiencies greater than 95% under optimum conditions. However, this efficiency is limited by dissipative losses in the components.

Based on the space charge polarization theory, the reduced and bamboo-like layered TiO2 nanotube arrays were designed and prepared by the voltage pulse anodization technique including reduction process of negative voltage. The reduction process synchronously introduces amount of oxygen vacancies, and the bamboo-like layered structure provides a plenty of interfaces to accumulate large amounts of free charges in the TiO2 nanotube arrays, which greatly enhance the space charge polarization in the TiO2 nanotube arrays. Thus, the capacitances of the reduced and layered TiO2 nanotube arrays are clearly increased, which further lead to the obvious enhancement of the electrowetting-on-dielectric (EWOD) responses. Furthermore, the reduced TiO2 nanotube arrays with bamboo-like layered structure were successfully used as the visual sensor to detect the NaCl and glucose concentration. Especially, it has higher sensitivity for the detection of the NaCl and glucose solution with low concentration.

The reason of the near-surface layer formation in the Surface Dielectric Barrier Discharge driven by negative voltage pulse has been analysed numerically. According to calculations, the thickness of this layer is around 4μm in atmospheric pressure air; it is inversely proportional to gas density and does not depend on applied voltage value and dielectric parameters. The electric field value inside a layer depends on applied voltage and changes from 60 to 600kV/cm for negative voltage pulse amplitudes from 4.5 to 24kV.

The Resistive-Capacitive (RC) model has been widely adopted for analysis of the electric field in oil-pressboard insulation under DC voltage. However, studies in this regard have indicated that the charge polarity effect in oil-pressboard insulation, namely the stronger adsorption of negative charges by pressboard, could not be adequately captured by the RC model. In order to analyze the electric field with due consideration of charge polarity effect, the present paper adopted the Kerr electro-optic techniques to have measured the electric field in the oil spacing under DC voltage for two experiments models with Model I having two oil spacing divided by a pressboard at the spacing ratio of 1:1, and the Model II at the spacing ratio of 1:2. As Model I is concerned, the strength of electric field in the upper oil spacing reached 1.61 times of the initial one under positive voltage and 1.60 times under negative voltage, while the field in the lower oil spacing registered as one eighth of the initial one under both positive and negative voltages. For Model II, the electric field strength in the upper oil spacing reached 2.3 times of the initial field under positive voltage and one fourth of that under negative voltage, showing much stronger charge polarity effect compared to that in Model I. In order to analyze the effect of interface charge on electric field, an electric field analysis model based on interface charge, named Interface Charge Polarity Effect (ICPE) Model, is proposed in this paper. Referring to the different adhesive abilities of positive and negative charges on pressboard, the influence of interface charge on electric field can be analyzed by the proposed model, which could make the contribution to the insulating design and proofread for the converter transformer.

The influence of electrodes on unipolar switching characteristics of a Pt/HfO2/Pt resistor with symmetric electrodes is investigated by comparing the reset voltage ( $V_{R})$ , set voltage ( $V_{S})$ , current at low resistance state ( $I_{\mathrm{ LRS}}$ ) and high resistance state ( $I_{\mathrm{ HRS}})$ , and $I_{\mathrm{ LRS}}/I_{\mathrm{ HRS}}$ with positive and negative voltage polarities. The values of $\pm V_{R}$ and $\pm V_{S}$ of the Pt/HfO2/Pt resistor for respective positive and negative polarities are very similarly distributed. Concerning current levels at two resistance states ( $I_{\mathrm{ LRS}}$ and $I_{\mathrm{ HRS}}$ ), however, unexpected asymmetric current characteristics of the Pt/HfO2/Pt symmetric resistor are observed. The asymmetric current behavior at the symmetric Pt/HfO2/Pt resistor indicates the role of different environments at top and bottom interfaces, although they are formed with the same electrode material using the same deposition method. Two types of interfaces, Pt/HfO2 and HfO2/Pt, are analyzed using X-ray photoelectron spectroscopy. The bottom interface of HfO2/Pt, postprocessed with insulating HfO2 film deposition, is probed nonstoichiometric HfO x and weak oxidation of Pt electrode and is influenced by the variation of the current levels and the current ratio at both high and low resistance states.

We studied the effect of bias voltage between slider and disk surfaces to reduce lubricant pickup by the slider. A perfluoropolyether (PFPE) lubricant film, which is coated on the disk surface, has been considered to be charged to a negative voltage by the airflow on the rotational disk surface. Because the PFPE lubricant film is negatively charged, the lubricant pickup should be reduced by a bias voltage with a negative voltage on the slider surface. We confirmed changes in the lubricant pickup in a lubricant pickup test conducted at different bias voltages. A positive voltage of the slider accelerated the lubricant pickup, whereas a negative voltage reduced it.