Parallel Metal Research Articles

Designing ZrO2-blended nanocomposite MIM capacitors for future OFET applications and their characterizations

Organic field-effect transistors (OFETs) have been exploited as sensors for a variety of applications due to their excellent advantages over diodes and other electronic devices. Capacitors are one of the key components of the OFET designs that consist of a dielectric layer sandwiched between two parallel metal plates. The dielectric layer should be thin and/or have a high k constant value to achieve a high capacitance value (Ci, areal capacitance), so more charge carriers can be accumulated at the interface between the dielectric and the organic semiconductor, for OFETs to operate under low voltage (< 3 V). In this study, high-k nanocomposites (NCs) of ZrO2 metal oxide ceramic nanoparticles (NPs) in varying concentrations blended in two different polymer matrixes, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cyanoethyl cellulose (CEC) have been utilised as the dielectric layer in metal-insulator-metal (MIM) capacitors. The physical and electrical properties of fabricated MIM capacitors were evaluated. The measured areal capacitance, Ci, values demonstrated a gradual rise with increasing ZrO2 metal oxide content in both polymer matrixes. ZrO2-PVDF-HFP-based capacitors exhibited a two-fold increase in Ci, 91.86 ± 6.1 nF/cm2 (a 140 % increase) for 10 wt % NP content. Similarly, areal capacitance values of 76 ± 3.03 nF/cm2 (a 45 % rise) was measured on MIMs using CZ10 dielectric layer. High average dielectric constant (k) values of 28.61 and 35.68 for CZ5 and PZ5, respectively) were obtained. As expected, leakage current density increased for higher NP % in polymer matrixes. Nevertheless, all MIMs yielded average leakage current density < 1.75 × 10−6 (A/cm2) at 2 V. Therefore, the reported nanocomposites are suitable dielectric layers for OFETs and as platforms for gas, chemical and photoactivated sensing devices.

Gold Nanoparticle (GNP) Enhanced Electroporation of Extracellular Vesicles to Promote Gene Loading

Gene therapy is an emerging and powerful therapeutic tool for treating diverse diseases via functional genetic material delivery to targeted defective genes in cells. Extracellular vesicles (EVs) are natural carriers released by all living cells, which are gaining attention for usage in advancing efficiency of therapeutic delivery due to their various advantageous properties, including; (i) cargo protection from enzymatic degradation, (ii) tissue-specific targeting, and (iii) high biocompatibility. EVs can be isolated from a targeted set of cells and used for therapeutic delivery as they can travel back to the same cell type due to their unique surface proteins and markers to release the genes at the specified site. One of the leading methods for cargo transfection into EVs is electroporation, which utilizes short-duration voltage pulses to create pores on the EV surface membrane, during which the cargo can enter. The voltage creates a potential difference between the less electrically conductive EV membrane and the more electrically conductive internal and external EV environments leading to the formation of these pores. This process is limited by the maximum pulse amplitude and duration the EVs can withstand for maximum pore formation and cargo encapsulation while still permitting membrane recovery afterward. We specifically use microfluidic electroporation, which we have previously found to be the most efficient in loading. This technique utilizes water-in-oil droplet encapsulation of the EVs which are then electroporated by voltage application as they pass through parallel metal electrodes. As the droplets pass through the microfluidic device, the non-conductive oil phase creates a barrier allowing for specific consistent and short-pulsed voltage delivery for each EV-encapsulated conductive water droplet [1]. We aim to increase efficiency of gene therapy loading into EVs using gold nanoparticle (AuNP) enhanced electroporation to provide higher concentration, targeted, and protected gene delivery. It has been shown that AuNP can increase the loading into cells during electroporation by allocating the electric voltage onto the cell surface creating a pulse strength focusing effect, allowing more pore formation without increasing the total voltage applied [2]. Due to similar surface properties, we hypothesized that AuNPs would provide a similar increase in transfection of EVs. To test this hypothesis, we electroporated green fluorescence protein (GFP) into EVs with the introduction of AuNPs at various concentrations. Fluorescence analysis through Cytation 5 and EV concentration measurement with Nanoparticle Tracking Analysis (NTA) revealed a close to double increase in the GFP molecules per EV with the AuNP incorporation. Assessment with NTA and Transmission Electron Microscopy showed that the AuNPs did not significantly change the size, concentration, zeta potential, or morphology of the EVs, compared to the native EVs without electroporation, for retaining the EV originality and integrity. Overall, AuNPs have the capacity to increase cargo transfection into EVs, allowing high-efficiency packaging for specific therapy delivery to enhance effectiveness of the treatment.[1] Geng, T., & Lu, C. (2013). Microfluidic electroporation for cellular analysis and delivery. Lab Chip, 13(19), 3803–3821. https://doi.org/10.1039/c3lc50566a[2] Zu, Y., Huang, S., Liao, W.-C., Lu, Y., & Wang, S. (2014). Gold Nanoparticles Enhanced Electroporation for Mammalian Cell Transfection. Journal of Biomedical Nanotechnology, 10(6), 982–992. https://doi.org/10.1166/jbn.2014.1797 Figure 1

Visualization of the Charging of Water Droplets Sprayed into Air.

Water droplets are spraying into air using air as a nebulizing gas, and the droplets pass between two parallel metal plates with opposite charges. A high-speed camera records droplet trajectories in the uniform electric field, providing visual evidence for the Lenard effect, that is, smaller droplets are negatively charged whereas larger droplets are positively charged. By analyzing the velocities of the droplets between the metal plates, the charges on the droplets can be estimated. Some key observations include: (1) localized electric fields with intensities on the order of 109 V/m are generated, and charges are expected to jump (micro-lightening) between a positively charged larger droplet and the negatively charged smaller droplet as they separate; (2) the strength of the electric field is sufficiently powerful to ionize gases surrounding the droplets; and (3) observations in an open-air mass spectrometer reveal the presence of ions such as N2+, O2+, NO+, and NO2+. These findings provide new insight into the origins of some atmospheric ions and have implications for understanding ionization processes in the atmosphere and chemical transformations in water droplets, advancing knowledge in the field of aerosol science and water microdroplet chemistry.

Innovative Design of Solid-State Hydrogen Storage and Proton Exchange Membrane Fuel Cell Coupling System with Enhanced Cold Start Control Strategy

This paper presents an innovative thermally coupled system architecture with a parallel coolant-heated metal hydride tank (MHT) designed to satisfy the hydrogen supply requirements of proton exchange membrane fuel cell s(PEMFCs). This design solves a problem by revolutionising the cold start capability of PEMFCs at low temperatures. During the design process, LaNi5 was selected as the hydrogen storage material, with thermodynamic and kinetic properties matching the PEMFC operating conditions. Afterwards, the MHT and thermal management subsystem were customised to integrate with the 70 kW PEMFC system to ensure optimal performance. Given the limitations of conventional high-pressure gaseous hydrogen storage for cold starting, this paper provides insights into the challenges faced by the PEMFC-MH system and proposes an innovative cold start methodology that combines internal self-heating and externally assisted preheating techniques, aiming to optimise cold start time, energy consumption, and hydrogen utilisation. The results show that the PEMFC-MH system utilises the heat generated during hydrogen absorption by the MHT to preheat the PEMFC stack, and the cold start time is only 101 s, which is 59.3% shorter compared to that of the conventional method. Meanwhile, the cold start energy consumption is reduced by 62.4%, achieving a significant improvement in energy efficiency. In conclusion, this paper presents a PEMFC-MH system design that achieves significant progress in terms of time saving, energy consumption, and hydrogen utilisation.

Integrated Janus nanofibers enabled by a co-shell solvent for enhancing icariin delivery efficiency

During the past several decades, nanostructures have played their increasing influences on the developments of novel nano drug delivery systems, among which, double-chamber Janus nanostructure is a popular one. In this study, a new tri-channel spinneret was developed, in which two parallel metal capillaries were nested into another metal capillary in a core–shell manner. A tri-fluid electrospinning was conducted with a solvent mixture as the shell working fluid for ensuring the formation of an integrated Janus nanostructure. The scanning electronic microscopic results demonstrated that the resultant nanofibers had a linear morphology and two distinct compartments within them, as indicated by the image of a cross-section. Fourier Transformation Infra-Red spectra and X-Ray Diffraction patterns verified that the loaded poorly water-soluble drug, i.e. icariin, presented in the Janus medicated nanofibers in an amorphous state, which should be attributed to the favorable secondary interactions between icariin and the two soluble polymeric matrices, i.e. hydroxypropyl methyl cellulose (HPMC) and polyvinylpyrrolidone (PVP). The in vitro dissolution tests revealed that icariin, when encapsulated within the Janus nanofibers, exhibited complete release within a duration of 5 min, which was over 11 times faster compared to the raw drug particles. Furthermore, the ex vivo permeation tests demonstrated that the permeation rate of icariin was 16.2 times higher than that of the drug powders. This improvement was attributed to both the rapid dissolution of the drug and the pre-release of the trans-membrane enhancer sodium lauryl sulfate from the PVP side of the nanofibers. Mechanisms for microformation, drug release, and permeation were proposed. Based on the methodologies outlined in this study, numerous novel Janus nanostructure-based nano drug delivery systems can be developed for poorly water-soluble drugs in the future.

Old Acquaintances and Novel Complex Structures for the Ni(II) and Cu(II) Complexes of bis-Chelate Oxime-Amide Ligands.

In the process of systematically studying the methylhydroxyiminoethaneamide bis-chelate ligands with polymethylene spacers of different lengths, L1-L3, and their transition metal complexes, a number of new Ni(II) and Cu(II) species have been isolated, and their molecular and crystal structures were determined using single-crystal X-ray diffraction. In all of these compounds, the divalent metal is coordinated by the ligand donor atoms in a square-planar arrangement. In addition, a serendipitously discovered new type of neutral Ni(II) complex, where the propane spacer of ligand L2 underwent oxidation to the propene spacer, and one of the amide groups was oxidised to the ketoimine, is also reported. The resulting ligand L2' affords the formation of neutral planar Ni(II) complexes, which are assembled in the solid state on top of each other, and yield two polymorphic structures. In both structures, the resulting infinite, exclusively parallel metal ion columns in ligand insulation may serve as precursor materials for sub-nano-conducting connectors. Overall, this paper reports the synthesis and characterisation of seven new anionic, cationic, and neutral Ni(II) and Cu(II) complexes, their crystal structures, as well as experimental and computed UV-Vis absorption spectra for two structurally similar Ni(II) complexes, yellow and red.

Heat transfer characteristics of solid-liquid interface on nanostructure surface under external electric field

With the size of high-performance electronic device decreasing (down to nanoscale), and the accompanying heat dissipation becomes a big problem due to its extremely high heat generation density. To tackle the ever-demanding heat dissipation requirement, intensive work has been done to develop techniques for chip-level cooling. Among the techniques reported in the literature, liquid cooling appears to be a good candidate for cooling high-performance electronic devices. However, when the device size is reduced to the sub-micro or nanometer level, the thermal resistance on the solid-liquid interface cannot be ignored in the heat transfer process. Usually, the interfacial thermal transport can be enhanced by using nanostructures on the solid surface because of the confinement effect of the fluid molecules filling up the nano-grooves and the increase of the solid-liquid interfacial contact area. However, in the case of weak interfacial couplings, the fluid molecules cannot enter into the nano-grooves and the interfacial thermal transport is suppressed. In the present work, the heat transfer system between two parallel metal plates filled with deionized water is investigated by molecular dynamics simulation. Electronic charges are applied to the upper plate and lower plate to create a uniform electric field that is perpendicular to the surface, and three types of nanostructures with varying size are arranged on the lower plate. It is found that the wetting state at the solid-liquid interface can change from Cassie state into Wenzel state with strength of the electric field increasing. Owing to the transition from the dewetting state to wetting state (from Wenzel to Cassie wetting state), the Kapitza length can be degraded and the solid-liquid interfacial heat transfer can be enhanced. The mechanism of the enhancing hart transfer is discussed based on the calculation of the number density distribution of the water molecules between the two plates. When the charge is further increased, electrofreezing appears, and a solid hydrogen bonding network is formed in the system, resulting in the thermal conductivity increasing to 1.2 W/(m·K) while the thermal conductivity remains almost constant when the electric charge continues to increase.

Multifunctional optical logic device based on nanoscale rectangular ring resonator

Integrated optical logic devices are essential building blocks for implementing all-optical arithmetic and logic unit. In this paper, an ultra-compact multifunctional optical logic device consisting of a rectangular ring resonator coupled with two parallel metal–insulator–metal waveguides is presented. The transmission characteristics of the structure are analyzed in detail via temporal coupled-mode theory. The finite-difference time-domain simulation results reveal that multiple logic functions can be implemented with the aid of the wavelength division multiplexing technique at different output ports. Specifically, all seven basic types of logic gates, half-adder, half-subtractor, and 2*4 decoder can be implemented by monitoring the transmission of through and drop ports at different wavelengths. More importantly, among these functions, six logic gates (OR, XNOR, NAND, NOR, XOR, and AND) and half-adder functions can be performed simultaneously; the NOT logic operation is performed with controllable output ports and selectable working wavelengths; the half-subtractor and 2*4 decoder functions can be operated simultaneously. The proposed logic device is characterized by a small area overhead, multifunctionality, fast response time, and ultrahigh-speed information processing. It may potentially be applied in on-chip universal and parallel photonic computing units.

Casimir–Lifshitz Frictional Heating in a System of Parallel Metallic Plates

The Casimir–Lifshitz force of friction between neutral bodies in relative motion, along with the drag effect, causes their heating. This paper considers this frictional heating in a system of two metal plates within the framework of fluctuation electromagnetic theory. Analytical expressions for the friction force in the limiting cases of low (zero) temperature and low and high speeds, as well as general expressions describing the kinetics of heating, have been obtained. It is shown that the combination of low temperatures (T &lt; 10 K) and velocities of 10–103 m/s provides the most favorable conditions when measuring the Casimir–Lifshitz friction force from heat measurements. In particular, the friction force of two coaxial disks of gold 10 cm in diameter and 500 nm in thickness, one of which rotates at a frequency of 10–103 rps (revolutions per second), can be measured using the heating effect of 1–2 K in less than 1 min. A possible experimental layout is discussed.

Three-sensor 2ω method with multi-directional layout: A general methodology for measuring thermal conductivity of solid materials

Anisotropic thermal transport plays a key role in both theoretical study and engineering practice of heat transfer, but accurately measuring anisotropic thermal conductivity remains a significant challenge. To address this issue, we propose the three-sensor 2ω method in this study, which is capable of accurately measuring the isotropic or anisotropic thermal conductivity of solid materials. In this method, several three-sensor groups following the design guidelines are fabricated upon the sample along different characteristic directions, and each group consists of three parallel metal sensors with unequal widths and distances optimally designed based on sensitivity analysis. Among the three sensors, the outer two serve as AC heaters and the middle one as a DC detector. The 2ω voltage signals across the detector in each three-sensor group are measured, and then the data are processed by the proposed Intersection Method to derive thermal conductivities along directions of interest. The application of the detector's 2ω instead of the heater's 3ω voltage signals eliminates errors introduced by the uncertainties of thermal resistance in superficial structures (metal layer, insulation layer, interface, etc.). Meanwhile, by replacing the fitting algorithm with the Intersection Method, the local optimum trap of multivariate fitting is avoided. To verify the accuracy and reliability, four typical monocrystalline semiconductors, i.e., Si, GaN, AlN, and β-Ga2O3, are measured, and the results are consistent with the literature. This method will provide a comprehensive and versatile solution for the thermal conductivity measurements of solid materials.

Design and Analysis of Complementary Metal–Oxide–Semiconductor Single-Pole Double-Throw Switches for 28 GHz 5G New Radio

We propose a single-pole double-throw (SPDT) switch with low insertion loss (IL), high isolation, and high linearity for a 28 GHz 5G new radio. The transmit (TX) path is a π-network consisting of a parallel dynamic-threshold metal–oxide–semiconductor (DTMOS) transistor, M1, with large body-floating resistance, RB (DTMOS-R M1), a series one-eighth-wavelength (λ/8) transmission line (TL), and a parallel capacitance, Cant. The series λ/8-TL in conjunction with the parallel Cant and transistors’ capacitance constitute an equivalent λ/4-TL with a characteristic impedance of 50 Ω. This leads to low IL in the TX mode and decent isolation in the receive (RX) mode. The RX path is an L-network constituting a series impedance (of parallel inductance L1 and DTMOS-R M2) and a parallel DTMOS-R M3. This leads to a decent IL in the RX mode and isolation in the TX mode. The first SPDT switch (SPDT SW1) is designed and implemented in a 90 nm complementary metal–oxide–semiconductor (CMOS) with a top metal thickness (TMT) of 3.4 μm. A comparative SPDT switch (SPDT SW2) in a 0.18 μm CMOS with a thinner TMT of 2.34 μm is also designed and implemented. In the TX mode, SPDT SW1 achieves a measured IL of 0.67 dB at 28 GHz and 0.58–1 dB for 17–34.9 GHz and a measured isolation of 44.3 dB at 28 GHz and 25.6–62.3 dB for 17–34.9 GHz, one of the best IL and isolation results ever reported for millimeter-wave CMOS SPDT switches. The measured input 1 dB compression point (P1dB) is 28.5 dBm at 28 GHz. Moreover, in the RX mode, SPDT SW1 attains a measured IL of 1.9 dB at 28 GHz and 1.83–2.1 dB for 25–38.3 GHz and an isolation of 25 dB at 28 GHz and 24.5–27 dB for 25–38.3 GHz. The measured P1dB is 24 dBm at 28 GHz.

Excitation of THz plasmonic eignmode of parallel plain waveguide by using GaAs material

A Terahertz wave incident on waveguide made up of two parallel thin metal plates sandwiching a thin region of GaAs semiconductor, excites a surface plasma wave (SPW), at the metal–semiconductor interface. As the frequency of SPW increases the real part of the propagation vector increases linearly where the imaginary part of the propagation vector decay parabolically. It is also observed that the distortion of the pulse due to the Terahertz wave (THz) has different component of different phase velocity. The proposed methodology entails the generation of terahertz plasmonic eigenmodes within a parallel planar waveguide composed of GaAs material. The areas of focus in this field include THz Waveguiding and Routing, THz Modulators and Switches, THz Sensing and Imaging and THz Integrated Photonics.

Electrostatic screening in a wire medium

We extensively study screening in anisotropic artificial media formed by arrays of parallel metal wires both analytically and experimentally. Our findings show that the electrostatic potential distribution produced by probe charge is spherically symmetrical in the vicinity of the source. We also derive a boundary condition for the wire medium and confirm its validity experimentally. Despite the finite dimensions of the wire arrays, the field symmetry near the charge remains unaffected, but a local maximum potential is produced at the boundary. The screening depth of the wire medium is determined by its geometrical parameters and is proportional to the plasma frequency, which leads us to propose an experimental method for defining plasma frequency through static E-field measurement.

Parallel metal–insulator–metal diode with an ultrathin spin-coated hydrogen silsesquioxane insulating layer

In this study, we investigated a parallel metal–insulator–metal (MIM) diode with an ultrathin spin-coated hydron silsesquioxane (HSQ) layer. Ti and Au were adopted as the metal electrodes for the large work function difference. Conditions to obtain the ultrathin HSQ layer with a thickness of below 5 nm for tunneling were predicted and Ti/HSQ/Au diode devices with a parallel electrode arrangement were fabricated by using the conditions. The typical current–voltage characteristics of the fabricated diodes exhibited asymmetry of about 1.8 at 3.0 V. It was demonstrated that the dynamic zero bias resistance of the diodes was as low as about 8 MΩ. Based on the Simmons model, the estimated oxide-equivalent thickness of HSQ in the device was about 1.7 nm, which was in good agreement with the prediction. The good figures of merit of the fabricated diodes imply that the spin-coated ultrathin HSQ is very suitable for this application.

Theory of dielectric photonic crystals sandwiched between parallel metal plates

Photonic crystals based on silicon-air-geometries sandwiched between parallel metal plates are studied theoretically. Compared with in-plane propagation in corresponding infinite-height photonic crystals, modes with one of the two possible polarizations are eliminated for small plate separations. Consequently, 2D photonic crystals that usually do not have a band gap for both polarizations possess a complete band gap in the sandwich geometry. A procedure for obtaining the maximum allowed photonic-crystal height between plates that preserves the in-plane band gap is described. The effect on the band gap of adding an air-gap or a silicon substrate to the photonic crystal structure between plates is also studied. Finally, it is shown that, for terahertz frequencies, a useful distance between metal plates is comparable to the thickness of thin silicon wafers, and that propagation losses are sufficiently small that the structures are of practical interest. We briefly discuss the numerical method that was used for calculating band diagrams and band gaps, which is based on a modification to the plane-wave-expansion method [R. D. Meade et. al., Phys. Rev. B 48, 8434 (1993)10.1103/PhysRevB.48.8434] based on an iterative search algorithm exploiting Fast Fourier Transforms for fast calculations.

Three-sensor 3ω-2ω method for the simultaneous measurement of thermal conductivity and thermal boundary resistance in film-on-substrate heterostructures

Solid heterostructures composed of substrates and epitaxial films are extensively used in advanced technologies, and their thermophysical properties fundamentally determine the performance, efficiency, and reliability of the corresponding devices. However, an experimental method that is truly appropriate for the thermophysical property measurement of solid heterostructures is still lacking. To this end, a three-sensor 3ω-2ω method is proposed, which can simultaneously measure the thermal conductivities of the film and the substrate, along with the film-substrate thermal boundary resistance (TBR) in a single solid heterostructure without any reference samples, showing broad applicability for miscellaneous heterostructures with film thickness ranging from 100 nm to 10 μm. In this method, three parallel metal sensors with unequal widths and distances conforming to guidelines for the three-sensor layout design are fabricated on the sample surface, in which the two outer sensors serve as heaters and the middle sensor as a detector. The respective 3ω signals of the two heaters and the 2ω signal of the detector are measured, and then the thermophysical properties of the sample are fitted within 3D finite element simulations. To verify this method, two typical wide bandgap semiconductor heterojunctions, i.e., GaN on SiC (#SiC) and GaN on Si (#Si) with ∼2.3 μm GaN epilayers, are measured. The thermal conductivity of the GaN film, the thermal conductivities of the SiC and Si substrates, and the GaN/substrate TBRs are derived, exhibiting good agreement with the literature. The proposed method will provide a comprehensive solution for the thermophysical property measurements of various solid heterostructures.

Enhanced Fano resonance for high-sensitivity sensing based on bound states in the continuum

Although previously reported terahertz absorbers can achieve high-sensitivity refractive index sensing, the resonant peak is too broad, which leads to a low figure of merit (FOM). Transmissive sensors based on bound states in the continuum (BIC) can achieve high FOM, but they have some limitations in high sensitivity. Herein, we propose a periodic triple parallel metal bars structure to obtain high quality, a strong field, and multiple hot spots by the Friedrich–Wintgen BIC. Numerical results show the sensitivity and FOM can reach 1877 GHz/RIU and 665, respectively. Compared to the previously reported transmissive sensors based on BIC, the sensitivity has been greatly improved.

A novel MOF-derived strategy to construct Cu-doped CeO2 supported PdCu alloy electrocatalysts for hydrogen evolution reaction

Hydrogen evolution reactions (HER) via water splitting is of significance for electricity-to-fuel conversion. The pursuits of rationally design and facile synthesis method for efficient HER catalysts have long been a subject of interest. In this work, a bimetallic MOF-derived strategy was constructed to realize doping and alloying of transition metal in parallel and Pd-CuCeOx catalyst was prepared, in which Cu served as doping element in CeO2 and secondary metal in Pd-Cu alloy. For the as-synthesized Pd-CuCeOx, an overpotential of 109 mV is needed to reach a current density of 10 mA cm−2 with a Tafel slope of only 30.9 mV dec−1. With the low content of precious metal, Pd-CuCeOx exhibited a high TOF value of 6.99 s−1, which is about 3.5 times higher than that of commercial Pt/C. The improved HER performance is attributed to the d-band structure modified by alloying and the enhanced electronic coupling caused by doping.

A hybrid circuit breaker with fault current limiter circuit in a VSC-HVDC application

A conventional hybrid circuit breaker (HCB) is used to protect a voltage source converter-based high voltage direct current transmission system (VSC-HVDC) from a short circuit fault. With the increased converter capacity, the DC protection equipment also requires a regular upgrade. This paper adopts a novel type of HCB with a fault current limiter circuit (FCLC), and focuses on the responses of voltage and current during DC faults, which are associated with parameter selection. PSCAD/EMTDC based simulation of a three-terminal VSC-HVDC system confirms the effectiveness and value of HCB with FCLC, by using an equivalent circuit modelling approach. Laboratory experimental tests validate the simulation results. The peak fault current is reduced according to the current limiting inductor (CLI) increase, and can be isolated more quickly. By adopting parallel metal oxide arrester (MOA) with the main branch of HCB, voltage stresses across the breaker components decrease during transient and continuous operation, and less energy needs to be dissipated by the MOA. The remnant current for all cases is transmitted to power dissipating resistor (PDR) in the final stage, and the fault current is reduced to the lowest possible value. When the current from the main branch is transferred to the FCLC branch, transient voltage spikes occur, while smaller PDR is required to absorb current in the final stage.

A Mannich-base imidazoline quaternary ammonium salt for corrosion inhibition of mild steel in HCl solution

The inhibition performance of a novel Mannich base-type imidazoline quaternary salt, namely [N, N-bis(propiophenone), N(-1-polyethyleneployamine-2-stearic-imidazole)] benzyl ammonium chloride (PPLC) for mild steel in 0.5 M HCl was investigated. The experimental results show that PPLC is an excellent corrosion inhibitor, which can retard both the anodic and cathodic reactions through strong chemisorption on the surface. The theoretical results from DFT and MD simulations imply that the active site of PPLC was concentrated on the imidazole ring, carbonyl group and benzene ring, and the PPLC could spontaneously adsorb on the surface of metal in a manner parallel.