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We studied the excitation-dependent photoluminescence (PL) quantum yield (QY) of monolayer MoS2 (1L-MoS2) with various flake areas grown on SiO2/Si substrates. The PL measurements were carried out by 532, 488, and 325 nm excitations which fulfill the conditions of quasi-resonant excitation of A-exciton, above bandgap, and far above the bandgap excitations, respectively. The PL QY was found to be reduced by decreasing the excitation wavelength, and it is attributed to variation in the thermal energy dissipated to the lattice. PL emission from 1L-MoS2 was observed with 325 nm excitation in large-area flakes (≥532 μm2) because of efficient heat dissipation. In the literature, PL emission of 1L-MoS2 is hardly reported with 325 nm laser excitations. Under 325 nm laser irradiation, 50% of excitation energy is converted to heat, which substantially increases the local temperature. From the temperature-dependent Raman analysis, the rise in the local temperature is approximated to be ∼382 K in the case of a small-area flake, whereas such an effect is alleviated in large-area flakes. Moreover, inter-valley exciton scattering dominates as the excitation wavelength decreases because of a substantial rise in the phonon population for small-area flakes. As a consequence of inter-valley exciton scattering, dark excitons (K-Σ) dominate over the bright excitons (K-K) under the 325 nm excitation. Hence, total suppression of PL emission was observed for small-area flakes because of dark exciton recombination. The noticeable PL emission of large-area flakes is attributed to the improved bright exciton recombination. [ABSTRACT FROM AUTHOR]

Performance, reliability, and costs are the three core attributes of any integrated circuits (IC) and microelectronics system products. Continuous advances of microsystem chips have been made possible by relentless physical scaling-down in IC technologies, predominantly in complementary metal-oxide-semiconductor (CMOS). Rapid ending of Moore's Law calls for smart futuristic chips, toward which CMOS+X heterogeneous integration emerges as the main and viable pathway where X represents various innovative, nontraditional technologies and devices to be hetero-integrated into Si CMOS platform to deliver superior system performance with rich functional diversities and ultra robust reliability at affordable costs. This mini-review discusses a few emerging CMOS+X technology advances addressing the performance and reliability challenges for advanced IC chips, including vertical magnetic-cored inductive devices for single-chip radio frequency IC integration, in the backend-of-the-line metal wall isolation to suppress flying noises in complex CMOS ICs, and nano crossbar array and graphene-based on-chip electrostatic discharge protection structures as design-for-reliability solutions for advanced chips. [ABSTRACT FROM AUTHOR]

Efficient heat dissipation and thermal protection present urgent challenges in high-power integrated circuits (ICs). Although applying a coating of highly thermally conductive materials on the surface of ICs is anticipated to mitigate heat concentration issues, ensuring thermal protection for adjacent devices continues to pose a challenge. Inspired by the microstructure of unidirectional nutrient transport in plant roots, this study utilizes magnetic liquid metal droplets to develop a high thermal conductivity network capable of adaptively manipulating the heat transfer path. This approach aims to tackle the challenges of heat concentration, disordered thermal dissipation, and thermal protection for high-power ICs, thereby enhancing thermal management efficiency. By controlling the distribution of the magnetic field, this study orchestrates the structure of the thermal conduction network to ensure rapid and orderly heat dissipation of ICs while simultaneously validating the network's thermal protection performance. The temperature in the IC thermal concentration zone reaches thermal equilibrium at 399.1 K when the ambient temperature is at 295 K. As the ambient temperature rises to 333 K, the temperature in the IC heat concentration zone stabilizes at approximately 400 K. Simultaneously, the temperature at a specific point in the thermal path of the network registers at 341 K, with the temperatures of the devices flanking this point at 314 K. The magnetron thermal conduction network, inspired by the root structure of bionic plants, not only boosts the thermal management efficiency of ICs but also shows promising application prospects in aerospace, electronics, and other related industries. [ABSTRACT FROM AUTHOR]

Superconducting digital circuits are promising technologies that can overcome bottlenecks in both classical and quantum computation due to their ultra-high operation speed and extremely low power dissipation. Superconducting nanowire cryotrons (nTrons) are emerging as one type of superconductor switching devices, offering advantages complementary to conventional Josephson junctions. Achieving monolithic integration of a reasonable number of nTrons into a functional digital circuit is a crucial step to extend its application. In this study, we constructed a monolithic integrated nTron-based binary encoder, which includes input fanout circuits, on-chip biasing, combinational logic routing and multi-gate nTrons. This represents a monolithic nTron digital circuit comprising 137 nTron gates, 424 resistors, 274 inductors, and 164 vias developed using a two-superconducting-layer fabrication process. The performance of this monolithic nTron encoder surpasses that of our previously demonstrated circuit with discrete nTron components. The maximum bias margin is 28% for the fanout circuit and 60% for the multi-gate nTron when using a signal generator, while the minimum timing jitter is 40 ps. The total power dissipation mainly from biasing resistors is 19.6 μW, making it more power efficient than RSFQ encoders. The encoder is then packaged and connected with a superconducting nanowire single-photon detector array for demonstrating its function of addressing pixel locations. Compared to the conventional readout, the nTron encoder shows a minimum readout error rate lower than 10−4 and reduces the readout RF lines from 15 to 4. The design and fabrication technologies could enrich integrated nTron digital circuits beyond current limits and promote their applications in classical and quantum systems. [ABSTRACT FROM AUTHOR]

The miniaturization, lightweight, and solidification of pulse forming lines (PFLs) are of prime significance during the evolution of pulsed power technology. In this paper, an all-solid-state annular pulse forming line (APFL) based on film-insulated coaxial transmission lines is developed to generate fast-rise time quasi-square pulses. First, a coiled coaxial transmission line (CCTL) comprised of multilayer polypropylene films with outstanding insulating properties is constructed. It can withstand direct current voltages up to 200 kV, with a cross section diameter of 7.4 mm. In addition, in order to turn the pulse transmission direction from circumferential to axial, a compact insulated terminal with a 90° bend structure is designed for CCTL. Although single terminal inductance can slow down the rising edge of the output pulse, their parallel connection in an APFL can weaken such an effect. The APFL, with a characteristic impedance of 2.95 Ω and a transmission time of 13 ns, is composed of three CCTLs with six terminals, which can run over 100 thousand times under the pulse voltage of 75 kV. Finally, 15 series APFL modules are employed to assemble a multi-stage PFL for the Tesla-type pulse generator. When charged to a voltage of 1 MV, the mixed PFL consisting of a coaxial line and the multi-stage PFL outputs quasi-square pulses with a voltage amplitude, rise time, and width of 510 kV, 4 ns, and 41.5 ns, respectively, and the fluctuation of the flat top is about 6%. [ABSTRACT FROM AUTHOR]

Dielectric charging aboard spacecraft and satellites is a persistent and pressing issue in materials design and applications. This study investigated the effect of electron irradiation on charge trapping and leakage properties in polymethyl methacrylate, which is necessary for determining the maximum permissible fluence of radiation before the material is pushed beyond its breakdown threshold in charged particle radiation-intense environments. It was observed that dielectric breakdown in the form of an electrostatic discharge event cannot be induced under the conditions of this experiment after an amount of time that is dependent on initial electron fluence. This time limit for which an electrostatic discharge can be induced was found to be longer for the lower beam current irradiations. The work presented here discusses the factors affecting charge leakage using a global electric field-driven model. [ABSTRACT FROM AUTHOR]

Droplet impacting on the solid substrate, which typically is a simple planar surface, has been extensively studied for various technological applications. Here, through numerical calculation, we explore the droplet impacting on a single hemispherical bead and double bead structures. Several key physical parameters have been taken into account, including the Weber number, wettability, and geometry of microstructures. We reveal the spatiotemporal evolution of the droplet pattern, the correlated physical parameters, and the underlying physical mechanisms (air cushion or bubble). These results provide theoretical guidance to control jump-off forces via the structure design and suitable wettability for the relevant applications such as erosion protection. [ABSTRACT FROM AUTHOR]

Traditionally, conductivity, a key parameter for evaluating the probability of electrostatic discharge, has been subscribed to the belief that it is a constant value. However, in actual working conditions, such as the low earth orbit environment, the conductivity value of dielectrics is not constant due to the variation in temperature. Therefore, it is of great practical significance to investigate the conductivity value of dielectrics in the time-varying field and explore the hidden mechanism of the charging phenomenon. In this paper, we investigated the dynamic conductivity value using polyimide during four temperature cycles. The result shows that there is a positive correlation between conductivity and temperature above the turning point temperature. However, when the temperature is lower than the turning point temperature, the conductivity value hardly changes with temperature. In the four cycles, the conductivity value in the same temperature decreases with the cycles. The space charge distribution test and the thermally stimulated current experiment are carried out to explain the charging phenomenon. The results show that the heterocharge accumulates continually and is captured by deep traps above 0.55 eV. It could be concluded that the thermally stimulated detrapping effect makes the charge trapping difficult, which results in the conductivity value in the same cycle changing with the temperature above the turning point temperature and the heterocharge accumulating. The trap-filling effect inhibits the charge conduction process, which makes the conductivity value in the same temperature to decrease with temperature cycles. [ABSTRACT FROM AUTHOR]

During the etching of the dielectric layer of semiconductors through plasma etching, numerous flake particles are generated in the etching equipment. These particles cause layout defects on the wafer and engender reduced yield on production lines. Accordingly, this study investigated how such flake particles could form in a chamber involving varying levels of deterioration on the electrostatic chuck surface and varying levels of by-product deposition. Moreover, we tested the effect of various electrostatic chuck discharge sequences and voltages on the deposition of these flake particles. Our experimental results revealed that selecting an appropriate radiofrequency power and a voltage discharge sequence protocol for the electrostatic chuck and using a low-frequency radiofrequency power supply could minimize the number of flake particles adhering to a wafer surface. In the proposed method, wafer contamination is controlled by suppressing unstable electric stress that arises when the etching chamber is coated with deposited by-products and the electrostatic chuck has a deteriorated surface. [ABSTRACT FROM AUTHOR]

The DC vacuum circuit breaker plays an important role in the quench protection system of the Comprehensive Research Facility for Fusion Technology (CRAFT) project. The study of the operating characteristics of vacuum circuit breakers can effectively improve breaking reliability. This article introduces the design and basis of the series double break DC vacuum circuit breaker for the CRAFT quench protection system. It adopts the electromagnetic repulsion driving method to ensure rapid action and the operating mechanism design to ensure the synchronization of the double break action. A magnetic shielding setting is proposed through simulation calculations to solve the uniformity of magnetic induction strength between breaks. Combining the test data of action characteristics with the theory of optimal opening distance for current zero crossing, a DC breaking platform for the vacuum circuit breaker was designed, and control strategies were determined, thus completing the 100 kA DC breaking experiment. The vacuum circuit breaker studied in this article meets the technical requirements of the CRAFT quench protection system and provides experience and experimental data for the design of high-current vacuum circuit breakers. [ABSTRACT FROM AUTHOR]

This paper analyzes an accident of abnormal increase of pole bus differential current and pole differential current of a converter station caused by line fault of a ±800 kV extra high-voltage direct current transmission project. After a lightning strike caused a short circuit and grounding of the DC line, the sudden voltage change protection of the DC line was triggered and the DC full voltage restart was successful. The pole bus differential current and pole differential current of the converter station have reached the protection set but have not reached the protection delay set; therefore, the differential protection has not acted. This paper first introduces the configuration principles of pole differential protection, pole bus differential protection, and line voltage sudden change protection for extra-high voltage converter stations. Second, the operation of the DC protection under this fault was analyzed in detail, and the reasons for the occurrence of pole bus differential current and pole differential current were also analyzed in this paper. Then, the range of equipment that caused the abnormal increase in differential current was identified. Finally, the lightning strike model was built on the real-time digital system, and the fault was simulated and replicated. It was determined that the abnormal increase in differential current was caused by the discharge of the pole bus surge arrester caused by the second lightning strike on the DC line. [ABSTRACT FROM AUTHOR]

Current CMOS single-photon detectors operating in Geiger mode use passive quenching, yielding slow recovery due to the RC delay. Active quenching of CMOS photon detectors operating in the Geiger mode requires external quenching circuitry that occupies a large area, reducing the fill factor and spatial resolution. Here, we demonstrate a self-quenched active recovery (SQUARE) single-photon detector having its recovery accelerated by a secondary carrier multiplication process. The device consists of two gain regions, one giving rise to the photon response and the other quenching the device and amplifying the residual current for a speedy self-recovery. The first gain region is a crystalline silicon p/n junction fabricated through a commercial CMOS process, and the second gain region is a carbon-doped amorphous silicon layer deposited on the top metal layer of a completed CMOS wafer. The SQUARE single-photon detector shows a Geiger-mode gain greater than 100 000 and achieved <30 ns self-recovery time, much faster than self-quenched and passively quenched single-photon avalanche photodiodes reported to date. [ABSTRACT FROM AUTHOR]

This work demonstrates forming-free and self-limiting resistive switching characteristics of non-stoichiometric WO3−x-based nanoscale devices without using any selector layer. Pt/W/WO3−x/Pt cross point and crossbar devices with individual cell dimensions of 200 × 400 nm2 have been fabricated using e-beam lithography, sputtering, and lift-off processes. The devices exhibited stable multi-level bipolar resistive switching with a high on/off ratio. In the crossbar device, the programmed resistance states were clearly distinguishable in the worst-case and arbitrary-case scenarios. The present study demonstrates that CMOS process-compatible WO3−x possesses great potential for designing future nanoscale resistive random access memories for high-density memory applications. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenides (TMDCs) are demonstrated to be appealing semiconductors for optoelectronic applications, thanks to their remarkable properties in the ultraviolet-visible spectral range. Interestingly, TMDCs have not yet been characterized when exposed to x rays, although they would be ideal candidates for optoelectronic applications in this spectral range. They benefit from the high cross section of the constituent heavy atoms, while keeping the absorption very low, due to the ultrathin structure of the film. This encourages the development of photodetectors based on TMDCs for several applications dealing with x rays, such as radioprotection, medical treatments, and diagnosis. Given the atomic thickness of TMDCs, they can be expected to perform well at low dose measurements with minimal perturbation of the radiation beam, which is required for in vivo applications. In this paper, the use of TMDCs as active materials for direct x-ray detection is demonstrated, using a photodetector based on a MoS2 monolayer (1L-MoS2). The detector shows a response to x rays in the range of 101–102 keV, at dose rates as low as fractions of mGy/s. The sensitivity of 1L-MoS2 reaches values in the range of 108–109µC Gy−1 cm−3, overcoming the values reported for most of the organic and inorganic materials. To improve the x-ray photoresponse even further, the 1L-MoS2 was coupled with a polymeric film integrating a scintillator based on terbium-doped gadolinium oxysulfide (Gd2O2S:Tb). The resulting signal was three times larger, enabled by the indirect x ray to visible photoconversion mechanism. This paper might pave the way toward the production of ultrathin real-time dosimeters for in vivo applications. [ABSTRACT FROM AUTHOR]

Although particle–laden electrostatic discharges are widely used in laboratories as well as in industrial applications, the mechanism of particle lifting for particles initially at rest in such highly unsteady systems is not well understood. A multiphase gas–particle solver is developed using the multiphase particle-in-cell (MP-PIC) approach to emulate the interaction of a compressible shock-dominated gas phase with the dense particle phase. First, the two-way coupled solver is initially used to study the interaction of a planar traveling shock with a vertical curtain of particulates. The gas and particle phase evolution was found to be in good agreement with a similar experimental study in Ling et al. [Phys. Fluids 24, 113301 (2012)]. Second, the MP-PIC code is used to study the interaction of an expanding blast wave with a thick bed of particles. The simulation considered forces such as quasi-steady drag, pressure-gradient, added-mass, Saffman, and Magnus forces. We observe that the vertical liftoff particles close to the shock impingement point in this configuration are associated with the quasi-steady drag, pressure gradient, and added-mass forces. Also, the Saffman lift and Magnus forces contribute to lifting particles located radially farther away from the shock impingement point. In addition, the study finds a decrease in particle lifting efficiency with decreasing plasma kernel length and shock strength. [ABSTRACT FROM AUTHOR]

This paper presents new experimental data that enable the observed processes in nonlinear ferrite lines to be related with the theoretical positions of the spin waves of the magnetization precession under the conditions of a high-power microwave. Such an approach has not been considered in earlier discussions on the subject and can contribute to the theory of the generation of oscillations in a gyromagnetic ferrite medium. These new aspects were used to design a new type of generator. The specific feature is the presence of regularity in the ferrite lines in the generation mode of microwave oscillations. The repeating regularity enabled the implementation of multistage pulse shape converters capable of operating in two modes and providing extreme parameters of the output pulses. Two variants of multistage converters of nanosecond high-voltage pulse shapes with a duration of ∼4 ns at a half-height and with an amplitude of −500 kV were designed and tested. The assembly of the converters and the driving generator are described in the stationary setup. In the first case, the rise time shortened to ∼45 ps, and the amplitude increased to −850 kV due to the sharpening of a pulse and the formation of a shock wave by the cascade of three nonlinear transmission lines. A record rate for the increase of the leading peak voltage of ∼15.5 MV/ns was reached. In the second case, the new approach for the generation of a sequence of subnanosecond pulses was presented and tested, and each pulse of the previous stage was modulated by the next stage doubling the number of pulses while conserving a deeper modulation. As a result, at the top of the incident pulse, a sequence of subnanosecond peaks with a large modulation depth (∼70%) was formed when the maximum voltage amplitude reached −700 kV. The results of the emission of such pulses are also presented. [ABSTRACT FROM AUTHOR]

Schottky's Conjecture (SC) posits that when a compound conductive structure is formed by placing a protrusion on top of an underlying base, the total field enhancement factor is the product of the field enhancement factors that would be produced by the base and protrusion in isolation. This is a powerful concept, which, in principle, allows separate treatment of the electrostatic effects of geometric features occurring at differing length scales. Recent work suggests that the degree to which the SC holds depends on the shape of the protrusion and base, and, in particular, on their relative sizes and their degree of self-similarity. Here, we use a Line Charge Model (LCM) to study the applicability of the SC to compound, quasiellipsoidal structures. The general features of compound structures produced by the LCM are discussed. The SC consistently overpredicted the computed field enhancement factor but was seen to provide reasonable estimates, correct to within a factor of 2 or better, when the protrusion was sufficiently small compared to the base; a dependence of the threshold protrusion height on the base radius was identified. This range of applicability of the SC is more restrictive than that previously reported in the literature, and potential causes of this are discussed. [ABSTRACT FROM AUTHOR]

The Electron Cyclotron Emission Imaging (ECEI) diagnostic was used to observe a finite-n interchange mode structure in the edge of negative triangularity shaped plasmas on DIII-D. At a small negative triangularity ( δ u = −0.2), the plasma is in the H-mode with ELMs that are triggered by a low-n interchange mode. At a larger negative triangularity ( δ u = −0.4) and low NBI power (2 MW), a dithering oscillation is observed that is triggered by a low-n interchange mode, whereas at higher NBI power (>2 MW), the edge reverts to L-mode and the low-n interchange mode is present continuously. In all cases, the edge pressure gradient is clamped when the interchange mode is present. It is concluded that the low-n interchange mode prevents the plasma from transitioning to H-mode at a large negative triangularity. This agrees with linear BOUT++ simulations which suggest that the interchange-type MHD can be a resistive ballooning mode whereby resistivity can significantly increase the finite-n ballooning mode growth rate. The absence of H-mode at large negative triangularity can, thus, be explained by the excitation of low-n pressure driven resistive ballooning modes in the plasma edge. [ABSTRACT FROM AUTHOR]

The work on the development of a generator of high-power, high-frequency pulses based on a nonlinear transmission line with saturated ferrite is presented. A feature of the generator is that the ferrite rings are saturated in the field of permanent magnets, unlike traditional generators with a solenoid wrapped around the transmission line. Due to the changed structure of the inner conductor, which is a corrugated conductor, the line has spatial dispersion. The paper demonstrates the generation of high-frequency pulses with a duration of up to 6 ns and a center frequency of 2.7 GHz. This pulse duration with a frequency above 2 GHz was not previously observed in traditional nonlinear transmission line geometry. The maximal peak power achieved was 70 MW for an incident voltage pulse of 90 kV. The energy efficiency of video pulse energy conversion into radio pulse was 6% [G. Kataev, Electromagnetic Shock Waves (Sov. Radio, Moscow, 1963)]. The paper discusses the performance of RF and microwave NiZn ferrites for the purposes of radio pulse generation. [ABSTRACT FROM AUTHOR]

To improve the triggering characteristics of the gas switch used for linear transformer driver, a method of corona assisted triggering based on the pre-ionization in switch gaps is proposed and applied to a six-gap gas switch. The principle is demonstrated by electrostatic field analysis and verified by the experimental study on the discharge characteristics of the gas switch. The results indicate that when the gas pressure is 0.3 MPa, the self-breakdown voltage remains about ±80 kV, and its dispersivity is lower than 3%. The effect of corona assisted triggering on the triggering characteristics increases with the higher permittivity of the inner shield. The positive trigger voltage of the switch with the proposed method can be reduced from 110 to 30 kV at a charging voltage of ±80 kV when the jitter is equal to that of the original switch. There are no pre-fire or late-fire when the switch operates continuously for 2000 shots. [ABSTRACT FROM AUTHOR]

Compared to linear accelerators, pulsed lasers have the characteristics of high efficiency, low cost, stable pulse output, and low environment interference for researching the transient dose rate effect (TDRE) on semiconductor devices. In this paper, pulsed laser radiation experiments are performed on a level-shifting transceiver. The experimental results are consistent with the results of the transient γ-ray radiation experiment, demonstrating the feasibility of using the pulsed laser in TDRE research on the level-shifting transceiver. This paper obtains theoretical and experimental conversion factors (CFs) through theoretical analysis and equivalency of the peak photocurrents, which are measured in pulsed laser and transient γ-ray radiation experiments. The CF results from the two approaches are within 7% of each other. In pulsed laser radiation experiments, an uncommon phenomenon is found. At the I/O (Input/Output) ports of the level-shifting transceiver, a trend of a positive photocurrent followed by a negative pulse is observed. A hypothesis is proposed that this photocurrent is produced by the turn-on and turn-off of the parasitic PNP (Positive-Negative-Positive) transistors in electrostatic discharge circuits at the level-shifting transceiver I/O ports. In addition, this hypothesis is verified by TCAD (Technology Computer Aided Design) simulations. [ABSTRACT FROM AUTHOR]

This paper focuses on the study of internal charging of four space used polymers: polyetheretherketone, fluorinated ethylene propylene, polyimide films, and epoxy based material (Epoxy FR4). Experiments were carried out for each material using the GEODUR facility (Toulouse, ONERA) that mimics the geostationary space environment behind shielding. Two different irradiation currents have been applied: 1 pA/cm2 and 10 pA/cm2. 1 pA/cm2 is used to analyze the charging behavior and the intrinsic electrical properties of each polymer. 10 pA/cm2 is used to study the influence of high electric field levels on their charging behavior. In this paper, two different numerical tools used for the study of internal charging are presented: Monte-Carlo Internal Charging Tool (MCICT) and Transport of Holes and Electrons Model under Irradiation in Space (THEMIS). MCICT has been used in the space community for several years. THEMIS has been recently developed at ONERA and is compared to MCICT. Both numerical tools showed consistent results for the 1 pA/cm2 integrated current but with deviations for the 10 pA/cm2 integrated current, supposedly due to nonlinear electric field effects on charge transport. THEMIS has a more refined physical model for the conductivity than MCICT. It studies more accurately the electron-polymer interactions and the charge transport kinetics of polymers under space radiations. Subsequently, the analysis of the underlying physical phenomena responsible for the polymers' charging behaviors will be carried out with THEMIS. In addition, studying these phenomena will permit to assess the risks of electrical discharges that may occur on a spacecraft in orbit (e.g., Geostationary (GEO) spacecraft) or during an elliptic trajectory (e.g., sub-GEO) in an Electric Orbit Raising case [E. Y. Choueiri, A. J. Kelly, and R. G. Jahn, J. Spacecr. Rockets 30(6), 749–754 (1993)]. [ABSTRACT FROM AUTHOR]

The NiCr igniter is a key element of MEMS-based electro-explosive device (mEED), while electrostatic discharge (ESD) may excite the igniter accidentally. To protect the NiCr igniter from damage by ESD, a novel NiCr igniter by integrating the igniter onto a TVS diode based substrate was designed and fabricated through semiconductor technology. The microscope photograph, resistivity, breakdown voltage, firing performance, and ESD protection ability were tested. The results show that the surface of the chip is smooth, the edges of key structures are clear, and there are no major scratches, cracks, and other phenomena on the whole device. The resistivity of all the TVS-mNiCr igniters is between 5 and 7 Ω, and the TVS diode resistance value is normal. The breakdown voltages of the eight types of TVS diodes with different structures are all between 3.5 and 5 V, and the TVS-mNiCr igniters can fire reliably at a constant current of 2 A. After the ESD test, the microscope of the igniter does not change significantly, meaning that the TVS-mNiCr igniter chip has a certain ability of ESD protection. It is of vital importance to guide the design of electrostatic tolerant ability for the MEMS-based electro-explosive device. [ABSTRACT FROM AUTHOR]

A fan-out circuit is a basic block for scaling up digital circuits for overcoming the limited driving capability of a single logic gate. It is particularly important for superconducting digital circuits as the driving power is typically weak for having high energy efficiency. Here, we design and fabricate a fan-out circuit for a superconducting nanowire cryotron (nTron) digital circuit. A classic splitter tree architecture is adopted. To transmit switching signal and avoid crosstalk among nTrons, we introduced an "R–L–R" interface circuit. Experimentally, a two-stage splitter tree of a fan-out number of four was demonstrated. Correct operation was observed with a minimum bit error rate (BER) of 10−6. The bias margin was 10% at BER of 10−4. The average time jitter was 82 ps. Moreover, crosstalk was not observed. Based on these results, we envision that the fan-out circuit can be used in future development of superconducting-nanowire-based circuits. [ABSTRACT FROM AUTHOR]

Maintaining the electric fields necessary for the current generation of noble liquid time projection chambers (TPCs), with drift lengths exceeding 1 m, requires a large negative voltage applied to their cathode. Delivering such high voltage is associated with an elevated risk of electrostatic discharge and electroluminescence, which would be detrimental to the performance of the experiment. The Xenon Breakdown Apparatus (XeBrA) is a 5-l, high voltage test chamber built to investigate the contributing factors to electrical breakdown in noble liquids. In this work, we present the main findings after conducting scans over stressed electrode areas, surface finish, pressure, and high voltage ramp speed in the medium of liquid xenon. Area scaling and surface finish were observed to be the dominant factors affecting breakdown, whereas no significant changes were observed with varying pressure or ramp speed. A general rise in both the anode current and photon rate was observed in the last 30 s, leading up to a breakdown, with a marked increase in the last couple of seconds. In addition, the position of breakdowns was reconstructed with a system of high-speed cameras and a moderate correlation with the Fowler–Nordheim field emission model was found. Tentative evidence for bubble nucleation being the originating mechanism of breakdown in the liquid was also observed. We deem the results presented in this work to be of particular interest for the design of future, large TPCs, and practical recommendations are provided. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate the capability of architected plates, with a frame-like cellular structure, to inhibit the propagation of elastic flexural waves. By leveraging the octet topology as a unit cell to design the tested prototypes, a broad and easy-to-tune bandgap is experimentally generated. The experimental outcomes are supported by extensive numerical analyses based on 3D solid elements. Drawing from the underlying dynamic properties of the octet cell, we numerically propose a tailorable design with enhanced filtering capabilities. We transform the geometry of the original unit cell by applying a uniaxial scaling factor that, by breaking the in-plane symmetry of the structure, yields independently tuned struts and consequently multiple tunable bandgaps within the same cell. Our findings expand the spectrum of available numerical analyses on the octet lattice, taking it a significant step closer to its physical implementation. The ability of the octet lattice to control the propagation of flexural vibrations is significant within various applications in the mechanical and civil engineering domains, and we note such frame-like designs could lead to advancements in energy harvesting and vibration protection devices (e.g., lightweight and resonance-tunable absorbers). [ABSTRACT FROM AUTHOR]

MoS2 is a prototypical two-dimensional van der Waals (vdW) solid, where covalently bonded S–Mo–S triplets are held together by weaker vdW forces. In this work, we have studied structural transformation from a three-dimensional amorphous phase of MoS2 into a layered vdW crystal using S L 2 , 3 edge x-ray absorption near-edge structure (XANES) spectroscopy with in-plane and out-of-plane polarized x-ray beam. The crystallization process, which starts from an isotropic amorphous phase, is accompanied by the establishment of vdW interaction between covalently bonded layers, resulting in the anisotropic nature of the crystalline phase. We have disclosed that the preferential growth of MoS2 layers along the (200) Bragg reflection commences immediately from the amorphous phase with no intermediate crystal orientations. We have additionally identified a unique signature in the S L 2 , 3 edge spectrum that is associated with vdW bonds and can be possibly used to determine sulfur-based single-layered and multi-layered transition metal dichalcogenides. [ABSTRACT FROM AUTHOR]

The efficiency of nanopore-based polymer sensing devices depends on the fast capture of anionic polyelectrolytes by negatively charged pores. This requires the cancellation of the electrostatic barrier associated with repulsive polymer-pore interactions. We develop a correlation-corrected theory to show that the barrier experienced by the polymer can be efficiently overcome by the addition of multivalent cations into the electrolyte solution. Cation adsorption into the pore enhances the screening ability of the pore medium with respect to the bulk reservoir which translates into an attractive force on the polymer. Beyond a critical multivalent cation concentration, this correlation-induced attraction overcomes the electrostatic barrier and triggers the adsorption of the polymer by the likecharged pore. It is shown that like-charge polymer-pore attraction is suppressed by monovalent salt but enhanced by the membrane charge strength and the pore confinement. Our predictions may provide enhanced control over polymer motion in translocation experiments. [ABSTRACT FROM AUTHOR]

Glow discharge with electrostatic confinement of electrons in a vacuum chamber allows plasma processing of conductive products in a wide pressure range of p = 0.01 – 5 Pa. To assist processing of a small dielectric product with a concentrated on its surface beam of fast neutral atoms, which do not cause charge effects, ions from the discharge plasma are accelerated towards the product and transformed into fast atoms. The beam is produced using a negatively biased cylindrical or a spherical grid immersed in the plasma. Ions accelerated by the grid turn into fast neutral atoms at p > 0.1 Pa due to charge exchange collisions with gas atoms in the space charge sheaths adjoining the grid. The atoms form a diverging neutral beam and a converging beam propagating from the grid in opposite directions. The beam propagating from the concave surface of a 0.24-m-wide cylindrical grid is focused on a target within a 10-mm-wide stripe, and the beam from the 0.24-mdiameter spherical grid is focused within a 10-mm-diameter circle. At the bias voltage U=5 kV and p~0.1 Pa, the energy of fast argon atoms is distributed continuously from zero to eU~5 keV. The pressure increase to 1 Pa results in the tenfold growth of their equivalent current and a decrease in the mean energy by an order of magnitude, which substantially raises the efficiency of material etching. Sharpening by the beam of ceramic knife-blades proved that the new method for the generation of concentrated fast atom beams can be effectively used for the processing of dielectric materials in vacuum. [ABSTRACT FROM AUTHOR]

The electrostatic discharge (ESD) from polymer insulators is one of the environment-related anomalies on spacecraft. Theoretically, to mitigate the ESD effects, we could modulate the secondary electron yield (SEY, σ) close to 1 in the entire energy range, suppressing surface charges. However, no single polymer insulator has been reported to achieve this seesaw-type modulation of SEY. Here, we exploringly designed and prepared MgO particles doped polytetrafluoroethylene (PTFE) composite coating to achieve this goal, which exhibits not only the reduced SEY characteristic of the microstructured PTFE coating at low energy but also the enhanced SEY characteristic of the double-layer structure of PTFE and MgO at high energy. The simulation and experiment results demonstrate that MgO particles doped PTFE coating achieves this seesaw-type modulation of SEY. The optimal MgO concentration is 20%, where the maximum SEY (σmax) changes from 2.0 to 1.1; the SEY at 10 keV (σ10k) changes from 0.6 to 0.8, and the higher energy of the SEY equal to 1 (Ep2) increases from 4.5 to 6.5 keV. The discharge test of the microstrip antennas with PTFE-MgO composite coating in a scanning electron microscope verifies the role of the seesaw-type SEY modulation in surface charge suppression. This study supplies an essential reference for suppressing surface charges on vacuum electronics based on modulation of secondary electron emission characteristics. [ABSTRACT FROM AUTHOR]

We present a simulation method to study electrolyte solutions in a dielectric slab geometry using a modified 3D Ewald summation. The method is fast and easy to implement, allowing us to rapidly resum an infinite series of image charges. In the weak coupling limit, we also develop a mean-field theory which allows us to predict the ionic distribution between the dielectric charged plates. The agreement between both approaches, theoretical and simulational, is very good, validating both methods. Examples of ionic density profiles in the strong electrostatic coupling limit are also presented. Finally, we explore the confinement of charge asymmetric electrolytes between neutral surfaces. [ABSTRACT FROM AUTHOR]

A hybrid deformable x-ray mirror consisting of a mechanical bender and a bimorph deformable mirror has been developed to realize adaptive optical systems, such as zoom condenser optics, for synchrotron-radiation-based x-ray microscopy. In the developed system, both bending mechanisms comprehensively contribute to the formation of the target mirror shape and can narrow the role of piezoelectric actuators, thereby enabling a more stable operation. In this study, the behavior of the bimorph mirror under the clamped condition was investigated, and the sharing of the deformation amount for each bending mechanism was optimized to minimize the amplitude of the voltage distribution of the bimorph mirror. [ABSTRACT FROM AUTHOR]

Conductive polymer composites enjoy specialized applications such as electrostatic discharge protection. In this work, we create interfacially localized graphene nanoplatelets (GNPs) in a cocontinuous polymer blend of polylactide (PLA) and poly(ethylene-co-vinyl acetate) (EVA). Based on the wetting coefficient analysis, GNPs favor localization in the EVA phase. A two-step compounding sequence is designed such that a PLA/GNP masterbatch is first prepared via solution blending, and then melt compounded with the EVA. In the second step, GNPs transfer from the PLA phase to the EVA phase but become kinetically trapped at the interface, as confirmed by electron microscopy. We achieve an ultralow percolation threshold of 0.048 wt. % GNPs and obtain blends with electrical conductivities of ∼10−5 S/cm at 0.5 wt. % GNP concentration. We systematically study the shear and extensional rheology of the ternary composite system. Cocontinuous blends with interfacial GNPs exhibit higher shear and extensional viscosities compared to samples with GNPs localized entirely within the EVA phase. Rheology, in situ dielectric measurements, and transmission electron microscopic imaging after nonlinear deformations all show the interfacial GNP network undergoes structure recovery and largely remains at the PLA/EVA interface. Moreover, high electrical conductivity is maintained during 2–10 min melt compounding and conductivity recovers with annealing after nonlinear deformations. These results suggest that these robust GNP networks preserve their bulk electrical conductivity during subsequent melt processing. [ABSTRACT FROM AUTHOR]

Nonlinear transmission lines (NLTLs) are typically driven by pulse forming lines (PFLs) or Marx generators to generate high repetition rate, high power microwaves (HPMs) with fewer auxiliary systems than conventional sources. This paper reports the development of an even more compact HPM system that utilizes a composite-based hybrid NLTL as the PFL and HPM generator in a single device. We designed the following three different combinations of nickel zinc ferrite (NZF) and barium strontium titanate (BST) inclusion volume loads in a polydimethylsiloxane host material to provide magnetic field dependent permeability and electric field dependent permittivity, respectively: 25% NZF, 10% BST/15% NZF, and 15% BST/10% NZF. By constructing the NLTL in a coaxial geometry, this device uses the capacitance and length of the NLTL to generate a fast rise-time high voltage pulse with microwave oscillations that occurred both during and after the pulse after exceeding a threshold charging voltage. The output frequency of the NLTLs ranged from 950 MHz to 2.2 GHz during the pulse for all volume loadings and was 1 GHz after the pulse for the 10% BST/15% NZF and 15% BST/10% NZF volume loadings. The oscillations generated after the pulse were much higher in amplitude and achieved 160 kW at a 15 kV charging voltage for the 15% BST/10% NZF composite-based NLTL. [ABSTRACT FROM AUTHOR]

Bardeen's model for the non-ideal metal-semiconductor interface was applied to metal-wrapped cylindrical nanowire systems of 30-400 nm in diameter; a significant effect of the nanowire diameter on the non-ideal Schottky barrier height was found. The calculations were performed by solving Poisson's equation in the nanowire, self-consistently with the constraints set by the non-ideal interface conditions; in these calculations, the barrier height is obtained from the solution, and it is not a boundary condition for Poisson's equation. The main finding is that thin nanowires are expected to have O(10 - 100) meV higher Schottky barriers compared to their thicker counterparts; an effect 3-4 times stronger than the diameter dependence of image-force barrier lowering in similar systems. What lies behind this effect is the electrostatic properties of metal-wrapped nanowires; in particular, since depletion charge is reduced with nanowire radius, the potential drop on the interfacial layer is reduced—leading to the increase of the barrier height with nanowire radius reduction. [ABSTRACT FROM AUTHOR]

We consider an electrolyte solution confined by infinitesimally thin semipermeable membranes in contact with a salt-free solvent. Membranes are uncharged, but since small counter-ions leak-out into infinite salt-free reservoirs, we observe a distance-dependent membrane potential, which generates a repulsive electrostatic disjoining pressure. We obtain the distribution of the potential and of ions, and derive explicit formulas for the disjoining pressure, which are validated by computer simulations. We predict a strong short-range power-law repulsion, and a weaker long-range exponential decay. Our results also demonstrate that an interaction between membranes does strongly depend on the screening lengths, valency of an electrolyte solution, and an inter-membrane film thickness. Finally, our analysis can be directly extended to the study of more complex situations and some biological problems. [ABSTRACT FROM AUTHOR]

The generation of high-power nanosecond radio frequency pulses is obtained by means of sequential commutation of silicon high voltage switches periodically placed in a nonlinear transmission line. The coaxial transmission line had the inner conductor made in the form of a corrugated periodic structure. The dispersive characteristics of the transmission line were optimized for RF generation by an electromagnetic shock front using numerical simulation. In the experiment, nanosecond RF pulses at frequency near 1 GHz were obtained for 2 kV incident pulses. The peak-to-peak amplitude of the excited oscillations reached about 30% of the amplitude of the incident pulse. [ABSTRACT FROM AUTHOR]

In space applications, space charge inside dielectric materials can lead to unwanted phenomena such as breakdown and electrostatic discharge. To prevent such incidents, the pulsed electroacoustic (PEA) device is employed to measure the space charge of dielectric samples. Unfortunately, most of the current PEA signal processing methods are inaccurate in studying the dielectric materials that attenuate and disperse the acoustic wave, as well as studying multi-layer or thin samples. A model under the PSpice software is developed in this work with the aim of improving the PEA signal processing. This model is an evolution of previous works, including the attenuation and dispersion of a polymer sample using the nearly local Kramers–Kronig relation. This model of the polymer sample is implemented into PSpice as a frequency dependent transmission line using Branin's method of characteristics model. A comparison of a model simulation and an experimental PEA signal obtained from a PTFE sample is presented. [ABSTRACT FROM AUTHOR]