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To date, the theoretical studies on dry abrasion on surfaces with microscopic roughness are based on JKR or DMT contact theory. Superhydrophobic nanocomposite coatings with low surface energy and microscopic surface roughness have extremely low real contact area and adhesion to the abrasive when subjected to contact and friction, making the above theories inapplicable. To date, there lack of theoretical studies on the dry abrasion characteristics of superhydrophobic nanocomposite coating surfaces. In response to this problem, a numerical understanding of the frictional force on superhydrophobic nanocomposite coatings is proposed based on Hertz contact theory, and the abrasion mechanisms of superhydrophobic nanocomposite coatings and its influencing factors are analyzed from the perspective of microscopic torque balance. The abrasion process is divided into three stages, and there exists a minimum value of bonding strength between the microstructure on the coating surface and the polymer matrix of the coating that determines whether abrasion will occur. This minimum bonding force is determined by Young's modulus of the polymer matrix, the radius of the microstructure, and the applied load. The conclusions can be a guide for the improvement of the anti-dry-abrasion property of superhydrophobic nanocomposite coatings from the perspective of coating preparation. [ABSTRACT FROM AUTHOR]

Based on the gas discharge theory involving distorted E-field enhancement, a physical model is proposed to estimate the switching delay for gas-insulated trigatron spark gaps with a trigger pin inside the main electrode. Two discovered breakdown modes, i.e., fast-breakdown mode (FBM) and slow-breakdown mode (SBM), can be unified in this model. Raether criterion can distinguish these two modes. If the main E-field and enhanced E-field near the trigger pin tip are great enough, FBM forms easily. Otherwise, if streamer development needs to rely on the second ionization process and relevant distorted E-field enhancement, the breakdown of the main gap would turn into SBM. The enhanced E-field near the trigger pin tip may affect the threshold main E-field of FBM. The distorted E-field enhancement may affect the switching delay length of SBM. [ABSTRACT FROM AUTHOR]

Diffuse discharge in atmospheric air can generate extremely high power density and large-scale non-thermal plasma. An achievable method of generating diffuse discharge is reported in this paper. Based on the resonance theory, a compact high-voltage repetitive nanosecond pulse generator (HRNPG) has been developed as discharge excitation source. The HRNPG mainly consists of repetitive charging circuit, Tesla transformer and sharpening switch. With the voltage lower than 1.0 kV, the primary repetitive charging circuit comprises two fast thyristors as low-voltage switches. A spiral Tesla transformer is designed to provide a peak transformation ratio of more than 100. The HRNPG prototype is capable of generating a pulse with over 100 kV peak voltage and ∼30 ns rise-time at the repetition frequency of 500 Hz. Using the copper line electrodes with a diameter of 0.4 mm, the gaps with highly non-uniform electric field are structured. With the suitable gap spacing and applied pulse, the glow-like diffuse discharge has been generated in line-type and ring-type electrode pairs. Some typical images are presented. [ABSTRACT FROM AUTHOR]

Presents rate equations for statistically averaged quantities of intense non-neutral beam propagation through a periodic solenoidal. Derivation of the global rate equation for general phase function; Discussion on the global energy balance and rate equations; Details on the coupled rate equations for the unnormalized beam emittance.

Investigates the detailed stability and transport properties of an intense ion beam propagating through an alternating-gradient focusing lattice with initial Kapchinskij-Vladimirskij (KV) distribution, using perturbative particle simulation techniques. Propagation of KV beam distribution over large distances.

We study the optimal sensing condition for periodic gold nanoslits. The intensity sensitivities for various periods, from 400 to 900 nm, were measured. The experimental results show that 500-nm-period array has a maximum bulk sensitivity, three times larger than the sensitivities of 400 and 700 nm periods. The optimal period is attributed to the coincidence of the surface plasmon resonance (SPR) wavelength and lowest imaginary dielectric constant of gold film. The structure reaches a figure of merit of 23.9 and achieves a detection limit of 2.6 × 10-5 refractive index units at 0.2% stability, better than the grating-based SPR sensors using intensity interrogation. [ABSTRACT FROM AUTHOR]

Large phase differences between transverse electric (TE) and transverse magnetic (TM) waves were investigated in plasmonic nanoslit arrays. The phase of the TE wave shifts ahead because of its low propagation constant. On the other hand, the phase of the TM wave is retarded due to the propagation of surface plasmons. The opposite phase shift forms a giant birefringence. Its magnitude was dependent on the width of nanoslits. The birefringence magnitude was ∼1 for 300-nm-wide nanoslits and up to ∼2.7 for 100 nm ones. The spectroscopic measurements indicate that waveplates made of gold nanoslits have large bandwidths. [ABSTRACT FROM AUTHOR]

Inspired by a well-known fact that the magnetic coercivity of a thin film has a strong dependence on its thickness, we have fabricated a 5×60 μm and 30 nm thick cobalt (Co) strip with thickness modulation along its long axis. The modulation period of 700 nm with a depth of 8 nm was prepared by a focused ion beam. From magnetic force microscope images, we observed an induced magnetic anisotropy along the short axis of the strip. By comparing out-of-plane magnetoresistance measurements in two magnetic remnant states, we extracted a positive domain wall resistance of 0.03 Ω, corresponding to 0.14% magnetoresistance (MR) in a Co thin film. [ABSTRACT FROM AUTHOR]

During the formation of a high current impulse discharge arc, objects near the discharge arc will be strongly impacted. In this paper, a high power, high current gas switch is used as the site of the impulse discharge arc. The explosion wave theory and the arc channel energy balance equation are introduced to analyze the development of the shock wave overpressure driven by the high current impulse discharge arc, and the demarcation point of the arc channel is given, from which the energy of the arc channel is no longer converted into shock waves. Through the analysis and calculation, it is found that the magnitude of the shock wave overpressure caused by impulse discharge arc expansion is closely related to the arc current rising rate. The arc shock wave overpressure will undergo a slow decay process and then decay rapidly. The study of this paper will perform the function of deepening the understanding of the physical nature of the impulse arc discharge, which can be used to explain the damage effect of the high current impulse discharge arc. [ABSTRACT FROM AUTHOR]

We present radio-frequency (RF) heating-assisted nanoimprint lithography (NIL) for the rapid fabrication of nanostructured biochips. The chips were spin-coated using a RF-sensitive polymer film, namely polyethylene terephthalate glycol-modified (PETG). The RF heating process takes advantage of rapid temperature increases and cooling for NIL. Using a patterned nickel film as the mold, various nanostructures, such as nanowire, nanorod, and nanogrid arrays, were successfully fabricated within several seconds. For surface plasmon biosensing chips, the silver-coated nanowire arrays achieved a linewidth of 6.01 nm and wavelength sensitivity of 550 nm per refractive index unit. The functionality of the sensor was verified by observing the label-free antigen-antibody interactions. [ABSTRACT FROM AUTHOR]

A pulsed-power generator using inductive adder technology is proposed for the case of a discharge gap. The merit of this generator is to merge the pulsed-voltage and pulsed-current adders via the dual secondary windings with special circuit. For the nonlinear impedance in any discharge gap, the standalone voltage-pulse and current-pulse can be outputted successively by this generator. The proposed generator is especially useful for the common resolution of implementing pulse discharge at less cost. As an application example, a compact trigger prototype was developed to compatibly use in the gas-insulated and vacuum switches. Experiments achieved good results that the triggered switches showed stable performance and long life. If the basic circuit of this proposed generator is regarded as a pulsed-generating unit, a certain number of such units connected in parallel can be expected to form a general device with generating greater breakdown-voltage and sustained-current pulses for discharge gaps. [ABSTRACT FROM AUTHOR]

For a compact and reliable nanosecond-pulse high-voltage generator (NPHVG), the specification parameter selection and potential usage of fast controllable state-solid switches have an important bearing on the optimal design. The NPHVG with closed transformer core and fast switching thyristor (FST) was studied in this paper. According to the analysis of T-type circuit, the expressions for the voltages and currents of the primary and secondary windings on the transformer core of NPHVG were deduced, and the theoretical maximum analysis was performed. For NPHVG, the rise-rate of turn-on current (di/dt) across a FST may exceed its transient rating. Both mean and maximum values of di/dt were determined by the leakage inductances of the transformer, and the difference is 1.57 times. The optimum winding ratio is helpful to getting higher voltage output with lower specification FST, especially when the primary and secondary capacitances have been established. The oscillation period analysis can be effectively used to estimate the equivalent leakage inductance. When the core saturation effect was considered, the maximum di/dt estimated from the oscillating period of the primary current is more accurate than one from the oscillating period of the secondary voltage. Although increasing the leakage inductance of NPHVG can decrease di/dt across FST, it may reduce the output peak voltage of the NPHVG. [ABSTRACT FROM AUTHOR]

This paper reports the formation of two-dimensional electron gas (2DEG) in rf-sputtered defective polycrystalline MgZnO/ZnO heterostructure via the screening of grain boundary potential by polarization-induced charges. As the MgZnO thickness increases, the sheet resistance reduces rapidly and then saturates. The enhancement of the interfacial polarization effect becomes stronger, corresponding to a larger amount of resistance reduction, when the Mg content in the cap layer increases. Monte Carlo method by including grain boundary scattering effect as well as 2D finite-element-method Poisson and drift-diffusion solver is applied to analyze the polycrystalline heterostructure. The experimental and Monte Carlo simulation results show good agreement. From low temperature Hall measurement, the carrier density and mobility are both independent of temperature, indicating the formation of 2DEG with roughness scattering at the MgZnO/ZnO interface. [ABSTRACT FROM AUTHOR]

In a high-powered single pulse system, the graphite electrode is better than other common metal electrodes for high energy transfer and pulse discharge. In this paper, the erosion mechanism of graphite electrode is investigated with the thermodynamics theory and the experimental results. Based on a simplified mathematical model, the graphite electrode erosion process of high-powered spark gap switch is also analyzed. The analysis results show that the relationship of the graphite electrode erosion and the charge transfer is linear, which is accordant with the experimental results. [ABSTRACT FROM AUTHOR]

A large-area and periodically patterned nanoporous aluminum grid with controlled pore size was fabricated by poly(ethylene oxide)-assisted self-assembly of polystyrene nanospheres. The grid layer was used as the shadow mask for the creation of nanochannels in a polymeric dielectric layer, as well as the base electrode in a space-charge limited transistor prepared thereafter. A high performance device with poly(3-hexylthiophene) as conducting semiconductor was achieved, yielding a high on-current output of ∼12 mA/cm2 and a high on-off ratio of ∼2 × 104 at a collector voltage of -2.0 V. [ABSTRACT FROM AUTHOR]

We have developed an approach to prepare large array nanostructured thin films using polyethylene oxide assisted self-assembly of polystyrene nanospheres as a template. By tuning the antidot diameter in the cobalt thin films, we found a crossover behavior in the magnetization reversal process. In addition, the effective moment per cobalt atom turns out to drop with growing antidot diameter which effectively increases the surface to bulk volume fraction. Our results suggest a tendency of reduced saturation magnetization in a ferromagnet/normal metal interface, where the mixing of itinerant electrons with ferromagnetic d electrons can give rise to observable effect. [ABSTRACT FROM AUTHOR]