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Radiofrequency microelectromechanical system (RF-MEMS) switches are utilized across a broad spectrum of industries, telecommunications, aerospace and smartphone technology.Herein, we proposed a new numerical and simulation analysis approach for spring constant (k) values as the characteristic mechanical parameters of RF MEMSs using the modified energy method (MEM). The proposed RF-MEMS switch was analyzed and simulated using the COMSOL package, and the findings confirmed that the alteration in the position and length (L) of the beams not only diminishes k significantly but also provides actuation-voltage VAC ultrasensitive structures and great concomitance between numerical and simulation k and VAC values. VAC value for the L-dependent numerical k (0.07 N m-1) was calculated to be 1.61 V which was validated with simulation outputs at 0.08 N m-1 and 1.80 V for k and VAC, respectively. Additionally, the switching time (ts), Von Mises Stress (VMS), natural frequency (fn) and mass (m) characteristic mechanical parameters were found to be 25.60 µs, 4.50 MPa, 3118.60 Hz , and0.21 ng, respectively. RF analysis was conducted in HFSS, revealing promising simulation results for the studied RF-MEMS switches. The return loss demonstrates excellent performance, registering better than -1 dB at 46 GHz. Furthermore, the insertion loss is noteworthy, exceeding expectations with values better than -0.7 dB at 46 GHz. Importantly, the isolation is impressive, exceeding -25 dB across the frequency range from 40 GHz to 35 GHz, all achieved with a modest actuation voltage of 1.8 V. This study contributes valuable insights intothe design and application of low-actuation-voltage RF-MEMS switches.

Voltage drop process in power Si diode switched to a conducting state by an impact-ionization wave, which is excited by overvoltage pulse with a subnanosecond rise time, has been investigated. In experiments, a reverse voltage pulse was applied to a diode with a diameter of 6 mm without preliminary reverse bias, which provided the average rate of voltage rise across the diode dU/dt in the range of 1–10 kV/ns. Numerical simulations showed that calculated and experimentally observed voltage waveforms are in good quantitative agreement in the case when an active area of the structure Sa, through which a switching current flows, increases with dU/dt value increasing. It was shown that at dU/dt < 2 kV/ns the active area tends to zero, and at dU/dt > 10 kV/ns it approaches the total area of the structure. Comparison with the results of similar studies shows that the increase in the active area of the structure with the increase in the Sa value does not depend on the material of the structure (silicon and gallium arsenide), the number of layers in the semiconductor structure (diodes and thyristors), and also on the value of the initial bias voltage. [ABSTRACT FROM AUTHOR]

Micro-Electro-Mechanical System (MEMS) switches have emerged as pivotal components in the realm of miniature electronic devices, promising unprecedented advancements in size, power consumption, and versatility. This literature review paper meticulously examines the key issues and challenges encountered in the development and application of MEMS switches. The comprehensive survey encompasses critical aspects such as material selection, fabrication intricacies, performance metrics including switching time and reliability, and the impact of these switches on diverse technological domains. The review critically analyzes the influence of design parameters, actuation mechanisms, and material properties on the performance of MEMS switches. Additionally, it explores recent advancements, breakthroughs, and innovative solutions proposed by researchers to address these challenges. The synthesis of the existing literature not only elucidates the current state of MEMS switch technology but also paves the way for future research avenues. The findings presented herein serve as a valuable resource for researchers, engineers, and technologists engaged in advancing MEMS switch technology, offering insights into the current landscape and guiding future endeavors in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

Radiofrequency microelectromechanical system (RF-MEMS) switches are utilized across a broad spectrum of industries, including telecommunications, aerospace, defense, and smartphone technology.Herein, we proposed a new numerical and simulation analysis approach for spring constant (k) values as the characteristic mechanical parameters of RF MEMSs using the modified energy method (MEM). The proposed RFMEMS switch was analyzed and simulated using the COMSOL package, and the findings confirmed that the alteration in the position and length (L) of the beams not only diminishes k significantly but also provides actuation-voltage VAC ultrasensitive structures and great concomitance between numerical and simulation k and VAC values. VAC value for the L-dependent numerical k (0.07 N m-1 ) was calculated to be 1.61 V which was validated with simulation outputs at 0.08 N m-1 and 1.80 V for k and VAC, respectively. Additionally, the switching time (ts), Von Mises Stress (VMS), natural frequency (fn) and mass (m) characteristic mechanical parameters were found to be 25.60 µs, 4.50 MPa, 3118.60 Hz, and0.21 ng, respectively. RF analysis was conducted in HFSS, revealing promising simulation results for the studied RF-MEMS switches. The return loss demonstrates excellent performance, registering better than -1 dB at 46 GHz. Furthermore, the insertion loss is noteworthy, exceeding expectations with values better than -0.7 dB at 46 GHz. Importantly, the isolation is impressive, exceeding -25 dB across the frequency range from 40 GHz to 35 GHz, all achieved with a modest actuation voltage of 1.8 V. This study contributes valuable insights intothe design and application of low-actuation-voltage RF-MEMS switches. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of nanosized polymer polyvinylidene fluoride (PVDF) thin ferroelectric films (two-dimensional ferroelectrics) and their composites with graphene layers, using molecular dynamics methods to (1) study and calculate the polarization switching time depending on the electric field and film thickness, (2) study and calculate the polarization switching time depending on changes of the PVDF in PVDF-TrFE film, and (3) study the polarization switching time in PVDF under the influence of graphene layers. All calculations at each MD run step were carried out using the semi-empirical quantum method PM3. A comparison and analysis of the results of these calculations and the kinetics of polarization switching within the framework of the Landau–Ginzburg–Devonshire theory for homogeneous switching in ferroelectric polymer films is carried out. The study of the composite heterostructures of the "graphene-PVDF" type, and calculations of their polarization switching times, are presented. It is shown that replacing PVDF with PVDF-TrFE significantly changes the polarization switching times in these thin polymer films, and that introducing various graphene layers into the PVDF layered structure leads to both an increase and a decrease in the polarization switching time. It is shown that everything here depends on the position and displacement of the coercive field depending on the damping parameters of the system. These phenomena are very important for various ferroelectric coatings. [ABSTRACT FROM AUTHOR]

This paper presents an analytical approach to envisage a suitable operating pressure and investigate the effect of squeezed-film damping on the transient response of a micromirror of size 200 µm × 200 µm and a deflection of 2.5 µm for space-based multiobject spectroscopy. While most MEMS devices are vacuum packaged to achieve a high Q and fast switching, the same may not be true for applications that are prone to vibrations and shocks. At small pressures, the micromirror can produce undesired deflections and oscillations, and hence, a high-pressure operation becomes necessary to alleviate these effects. The operating pressure and its effect on the transient response of the micromirror are investigated by solving linearized Reynold's equation and dynamic equation of motion using the numerical iteration method. The result shows an overdamped response above 10 kPa pressure. At 101 kPa, the micromirror exhibits a switching and release time of 102 µs and 95 µs, respectively. The analytical results are very close to the FEM results with a deviation of 8%. The result shows that operating a micromirror at atmospheric pressure serves the dual purpose of dispensing away with the requirement of vacuum packaging and providing immunity from vibrations and oscillation. [ABSTRACT FROM AUTHOR]

We present our findings on how orange peel coupling (OPC) between the ferromagnetic layers affects spin transfer torque-assisted magnetization reversal dynamics in CoPt, CoFeB, and EuO pentalayer nanopillar devices. We accomplish this by solving the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation (dynamical equation) using the Runge-Kutta fourth-order numerical technique. To begin, we examine the influence of OPC on switching times by simulating the LLGS equation separately for each pentalayer device, both with and without OPC. The magnetization switching times for CoPt, CoFeB, and EuO devices in the absence of OPC are 58 ps, 82 ps, and 154 ps, respectively. When introducing OPC in the pentalayer alloys, we observe a reduction in switching times of 3.5%, 11%, and 40% for CoPt, CoFeB, and EuO devices, respectively. Furthermore, we calculate the current density required to reverse the magnetization of the free layer in CoPt, CoFeB, and EuO pentalayer devices, which is found to be 0.78 × 10 12 A / m 2 , 1.8 × 10 12 A / m 2 , and 4.4 × 10 12 A / m 2 , respectively. In addition, we investigate how the thicknesses of the free and spacer layers, as well as the wavelength and amplitude of interface roughness, affect the magnetization switching time. Understanding the effects of OPC paves the way for the practical implementation of spin transfer torque (STT)-based memory devices. [ABSTRACT FROM AUTHOR]

Solid oxide electrolysis cells have emerged as a promising technology for renewable energy storage. The intermittent operation, however, could jeopardize durability. Understanding the transient response characteristics of the solid oxide electrolysis cell under diverse electrical inputs is crucial to comprehend the dynamic durability of the electrolysis cell. Yet, the electrochemical and temperature dynamic responses are challenging to be in-situ measured. In this study, a three-dimensional electrochemical-mass-heat coupled dynamic model of the solid oxide electrolysis cell is established and validated by the experimental I–V curve and electrochemical impedance spectroscopy data. The current and voltage manipulations on the transient responses are evaluated and the cause of voltage overshoot during current control is analyzed. The effects of amplitude and switching time of current upward manipulation on the electrochemical and thermal responses are also investigated. It is discovered that 40% current upward (60% power upward) slightly exceeds the upper limit of the temperature gradient of 8 K/cm and approaches the FU limit of 90%. On the other hand, the influence of switching time on safety performance is negligible. [Display omitted] • A 3D transient numerical model for solid oxide electrolysis cell is developed. • Dynamic response under current and voltage manipulations is compared. • Voltage overshoot is examined by thermal-decoupled analysis and EIS. • Amplitude and switching time of current upward is investigated. • Safety operation is discussed in regarding with temperature gradient and FU. [ABSTRACT FROM AUTHOR]

Disassembling discarded electrical products plays a crucial role in product recycling, contributing to resource conservation and environmental protection. While disassembly lines are progressively transitioning to automation, manual or human–robot collaborative approaches still involve numerous workers dealing with hazardous disassembly tasks. In such scenarios, achieving a balance between low risk and high revenue becomes pivotal in decision making for disassembly line balancing, determining the optimal assignment of tasks to workstations. This paper tackles a new disassembly line balancing problem under the limitations of quantified penalties for hazardous component disassembly and the switching time between adjacent tasks. The objective function is to maximize the overall profit, which is equal to the disassembly revenue minus the total cost. A mixed-integer linear program is formulated to precisely describe and optimally solve the problem. Recognizing its NP-hard nature, a metaheuristic algorithm, inspired by human idea generation and population evolution processes, is devised to achieve near-optimal solutions. The exceptional performance of the proposed algorithm on practical test cases is demonstrated through a comprehensive comparison involving its solutions, exact solutions obtained using CPLEX to solve the proposed mixed-integer linear program, and those of competitive peer algorithms. It significantly outperforms its competitors and thus implies its great potential to be used in practice. As computing power increases, the effectiveness of the proposed methods is expected to increase further. [ABSTRACT FROM AUTHOR]

The physics behind the switching kinetics of memristors is gradually becoming clearer. The periods required for the onset of electromigration within memristors and the activation or deactivation of the low‐resistance state—referred to as the incubation and switching times—exhibit non‐linearity with applied voltage. This behavior prevails depending on the rate‐limiting step comprising nucleation and filament growth, electron transfer at the electrode/electrolyte interface, and ion migration through the electrolyte. Herein, a model is introduced for ion migration as the rate‐limiting step. This model analyses the incubation time and analytically correlates it with the electric field, diffusion coefficient, and temperature, facilitating the determination of threshold voltage and diffusivity from high to low resistance states for ion migration as the rate‐limiting step. By exploring parallel plate cells with Yttria‐Stabilized Zirconia (YSZ) of nanometer thickness, the application of the model is illustrated and the fundamental equations are applied to outstanding memristive cells in the literature. The applicability of this model to cells of various charge carriers is proposed, ranging from vacancies and electron transport to oxygen ions and metal cations, denoting its potential importance. [ABSTRACT FROM AUTHOR]

Abstract The physics behind the switching kinetics of memristors is gradually becoming clearer. The periods required for the onset of electromigration within memristors and the activation or deactivation of the low‐resistance state—referred to as the incubation and switching times—exhibit non‐linearity with applied voltage. This behavior prevails depending on the rate‐limiting step comprising nucleation and filament growth, electron transfer at the electrode/electrolyte interface, and ion migration through the electrolyte. Herein, a model is introduced for ion migration as the rate‐limiting step. This model analyses the incubation time and analytically correlates it with the electric field, diffusion coefficient, and temperature, facilitating the determination of threshold voltage and diffusivity from high to low resistance states for ion migration as the rate‐limiting step. By exploring parallel plate cells with Yttria‐Stabilized Zirconia (YSZ) of nanometer thickness, the application of the model is illustrated and the fundamental equations are applied to outstanding memristive cells in the literature. The applicability of this model to cells of various charge carriers is proposed, ranging from vacancies and electron transport to oxygen ions and metal cations, denoting its potential importance.

Two series of W-doped V2O5 films, planar films, and inverse opal films, were synthesized. The evolution of their electrochromic properties, including switching time, cycling stability, and color efficiency (CE), were systematically investigated as a function of electrochemical impedance. Both charge transfer resistance (Rct) and ion diffusion ability (KΩ) increase with the W:V atomic ratio in both planar films and inverse opal films series. KΩ plays a decisive role on coloration switching time, for instance, there exists a range of KΩ where switching time vastly decreases with an increase of KΩ and beyond this range, switching time is independent of KΩ and remains constant. The introduction of macroporosity, however, greatly reduces the low critic KΩ. CE is co-affected by both KΩ and Rct. KΩ and Rct collaboratively impact on EC cycling stability: KΩ plays a key role on cycling stability since the best cycling stability corresponds to highest KΩ. Rct plays its role only when it is low enough to reduce the possibility of chemical dissolution of the intermediate product of vanadium-containing ions: the present critical value could be around 76 Ω.

Objective: The objective of this study was to assess the effectiveness of switching from omalizumab to another biologic therapy for patients with severe asthma and evaluate factors that influenced the decision to switch and determined the optimal time for a good biologic response. Subjects and Methods: A retrospective study of severe asthma patients was conducted at Al-Rashed Allergy Center, a tertiary center in Kuwait. After meeting the eligibility criteria, patients were divided into two comparative groups: those continuing with omalizumab and those who started with omalizumab but switched to another biologic. Results: One hundred sixteen patients with severe asthma were recruited, and only 33 had access to multiple biological treatments. Approximately 22.4% switched from omalizumab. Male patients with a history of ischemic heart disease, chronic rhinosinusitis, and nasal polyps were more likely to switch if they had higher levels of eosinophils in the sputum. This study showed that every 1% increase in sputum eosinophils doubled the likelihood of a switch. Patients with access to alternative biological options had a much shorter mean duration of omalizumab therapy before switching compared to those with only affordable omalizumab: 4.9 ± 1.5 years versus 8.9 ± 1.3 years (p < 0.001). The optimal time to predict the likelihood of a good response was less than 5.5 years, with an area under the curve of 0.91 and p = 0.003. This cutoff point provided a sensitivity and specificity of approximately 89% and 100%, respectively. Conclusion: An early transition from omalizumab, specifically within the first 5 years of treatment, in patients with severe asthma and higher sputum eosinophils may enhance the likelihood of a good response if other biological therapies were available. [ABSTRACT FROM AUTHOR]

Recent development in optical networking employing wavelength division multiplexing (WDM) fulfills the high bandwidth demand applications. Failure of such networks, leads to enormous data and revenue loss. Protection is one of the key techniques, which is used in designing survivable WDM networks. In this paper we compare dedicated and shared protection strategies employed inWDMmesh networks to protect optical networks failure, particularly fiber failure. Dijkstra’s shortest path algorithm is considered for carrying out simulations. The paper compares the performance of protection schemes, such as, dedicated path protection (DPP), shared path protection (SPP) and shared link protection (SLP) schemes. Capacity utilization, switching time and blocking probability are the parameters considered to measure the performance of the protection schemes. Simulation results show that, SPP is more efficient in terms of capacity utilization over DPP and SLP schemes, whereas, SLP offered better switching time than both DPP and SPP schemes. The average call drop rate is minimum for shared path protection scheme and maximum for shared link protection scheme.

Disassembling discarded electrical products plays a crucial role in product recycling, contributing to resource conservation and environmental protection. While disassembly lines are progressively transitioning to automation, manual or human–robot collaborative approaches still involve numerous workers dealing with hazardous disassembly tasks. In such scenarios, achieving a balance between low risk and high revenue becomes pivotal in decision making for disassembly line balancing, determining the optimal assignment of tasks to workstations. This paper tackles a new disassembly line balancing problem under the limitations of quantified penalties for hazardous component disassembly and the switching time between adjacent tasks. The objective function is to maximize the overall profit, which is equal to the disassembly revenue minus the total cost. A mixed-integer linear program is formulated to precisely describe and optimally solve the problem. Recognizing its NP-hard nature, a metaheuristic algorithm, inspired by human idea generation and population evolution processes, is devised to achieve near-optimal solutions. The exceptional performance of the proposed algorithm on practical test cases is demonstrated through a comprehensive comparison involving its solutions, exact solutions obtained using CPLEX to solve the proposed mixed-integer linear program, and those of competitive peer algorithms. It significantly outperforms its competitors and thus implies its great potential to be used in practice. As computing power increases, the effectiveness of the proposed methods is expected to increase further.

BackgroundSpatial pattern formation is a critical issue in developmental biology. Gene expression boundary sharpening has been observed from both experiments and modeling simulations. However, the mechanism to determine the sharpness of the boundary is not fully elucidated.ResultsWe investigated the boundary sharpening resulted by three biological motifs, interacting with morphogens, and uncovered their probabilistic landscapes. The landscape view, along with calculated average switching time between attractors, provides a natural explanation for the boundary sharpening behavior relying on the noise induced gene state switchings. To possess boundary sharpening potential, a gene network needs to generate an asymmetric bistable state, i.e. one of the two stable states is less stable than the other. We found that the mutual repressed self-activation model displays more robust boundary sharpening ability against parameter perturbation, compared to the mutual repression or the self-activation model. This is supported by the results of switching time calculated from the landscape, which indicate that the mutual repressed self-activation model has shortest switching time, among three models. Additionally, introducing cross gradients of morphogens provides a more stable mechanism for the boundary sharpening of gene expression, due to a two-way switching mechanism.ConclusionsOur results reveal the underlying principle for the gene expression boundary sharpening, and pave the way for the mechanistic understanding of cell fate decisions in the pattern formation processes of development.

DC-DC converters are used in many power electronics applications including PV integrated system to boost the voltage to the required level. Many isolated and nonisolated DC-DC converter topologies are used to improve the performance of the PV system. Based on the voltage level and conversion efficiency suitable topology is selected for an application. Performance of the DC-DC converter is evaluated based on inrush current, settling time, switching time, switching losses, switching stress, power output, filter requirement and conversion efficiency. It is very much important to select an appropriate topology for a desired application considering the above parameters. In this work, design and analysis of non-isolated and isolated converters namely conventional boost converter, boost converter with interleaved operation, flyback converter and flyback converter with interleaved operation is evaluated for 200W PV integrated DC-DC converter system. Switching characteristics and its effect on efficiency of power converters is evaluated. [ABSTRACT FROM AUTHOR]

The influence of different doses of gamma radiation on the phase transition temperatures, permittivity, conductivity, tilt angle, anchoring energy coefficients, spontaneous polarisation, rotational viscosity, and switching time of two-room temperature antiferroelectric liquid crystal (AFLC) mixtures has been investigated. At low radiation exposure, phase transition temperatures and optical tilt angles of the systems decrease slightly, but the effect is significant at high radiation doses. The permittivities as well as the ac and dc conductivities of the mixtures were significantly altered by γ-irradiation. Anchoring energy coefficients, spontaneous polarisation, rotational viscosity and switching time of the mixtures are shown to have a similar type of behaviour in both mixtures at low radiation doses, but their behaviour becomes random at higher levels of γ-irradiation. [ABSTRACT FROM AUTHOR]

• The dynamic response of VAM combustion is experimentally evaluated. • Decreasing switching time from 90 to 60 s reduces the outlet peak temperature by 5 °C. • The critical average temperature for thermal destabilization is identified to be 780 °C. • Feasible strategies to enhance system stability are demonstrated. Proper mitigation and utilization of coal mine ventilation air methane (VAM) are important to alleviate resource shortage and environmental issues. This work presents a pilot-scale experimental analysis of heat storage and oxidation performance in a VAM-fuelled reversal flow reactor, aiming at elucidating the thermal destabilization behaviour and providing feasible ways to maintain the system stability. Experimental results show that the system could become unstable under variable conditions. When the methane concentration is varied from 0.74 % to 0.70 %, the temperature is gradually becoming steady after operating the system for 5160 s. However, this balance will be broken, and the combustor is extinguished if the methane concentration is decreased from 0.68 % to 0.64 %. A critical average temperature of 780 °C in the combustion chamber is identified, below which the system starts to become unstable. Further analysis reveals the importance of heat-releasing proportion from the regenerator to the fresh gases in determining the system performance with the methane concentration varied. A sufficiently low proportion implies that the fresh gases cannot be properly preheated when entering the combustion chamber. Finally, increasing ventilation gas flow rate and reducing switching time are shown to be effective in promoting the oxidation process due to the enhanced heat storage. [ABSTRACT FROM AUTHOR]

For the silicon photonics integrated circuits, the optical switch plays a vital role in many applications. Large scale integration requires low switching power and fast switching speed. However the switching time and switching power of silicon thermo-optic switch are typically limited to tens of micro-seconds and tens of milli-watts, respectively. In this paper, we designed and fabricated a silicon thermo-optic switch with spiral optical phase shifters, which can reduce the switching power from 21.5 mW to 8.73 mW compared to the optical switch with straight phase shifters. Furthermore, we optimized the pulse driving, we proposed the calculation formula of the pulse voltage, and the overall quantitative scheme of the pulse voltage and pulse width. By adopting the optimized pulse driving, the switching time is reduced from 27 μs to 4 μs. The proposed silicon thermo-optic switch unit with optimized pulse driving is very promising for the applications where large scale integration of optical switches is needed.

The oscillatory interlayer exchange coupling (OXC) between ferromagnetic layers sandwiched by non-magnetic spacer layers plays a significant role in spintronic device function. In this work, the effect of OXC on the current-induced magnetization switching process in four different pentalayer nanopillar alloys is numerically investigated by solving the dynamical equation governed by the Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation. The four nanopillars consist of four ferromagnetic alloys, CoPt, CoFeB, Fe 85 B 13 Ni 2 and EuO, which serve as pinned layers and free layers, with copper forming a spacer layer between all the layers. The critical current density required to switch the magnetization of the free layer is computed for all the devices and the values are 0.6 × 10 11 Am - 2 , 1.31 × 10 11 Am - 2 , 2.24 × 10 11 Am - 2 , 3.27 × 10 11 Am - 2 for CoPt, CoFeB, Fe 85 B 13 Ni 2 and EuO device, respectively. Then we studied how the thickness of the Cu layer influences the OXC field. Furthermore, we investigated the effect of Cu layer thickness on critical current density and magnetization switching time for all the four devices by numerically solving the LLGS equation and they exhibit oscillating behaviour. We can reduce the critical current density and switching time substantially by controlling the OXC field acting on the free layer and choosing the magnetic material having low saturation magnetization as the free layer. The OXC field is optimised by fixing the Cu spacer thickness from 1.7 to 1.9 nm in the pentalayer nanopillar device. [ABSTRACT FROM AUTHOR]

This paper presents a radio frequency (RF) triple pole triple throw 3P3T cross antenna switch for cellular mobile devices. The negative biasing scheme was applied to improve the power-handling capability and linearity of the switch by increasing the maximum tolerable voltage drop across the drain and source and reverse biasing the parasitic junction diodes. To avoid signal reflection through the antenna in off-state, all the antenna ports were equipped with 50-ohm termination to provide the pull-down path. Considering the simultaneous operation of antenna ports in different switch cases, the presented T-type pull-down path demonstrated improvement of isolation by over 15 dB. Using stacked switches, the 3P3T handled the input power level of over 35 dBm. The chip was manufactured in 65 nm complementary metal oxide semiconductor (CMOS) silicon on insulator (SOI) technology with a die size of 790 × 730 µm. The proposed structure achieved insertion loss, isolation, and voltage standing wave ratio (VSWR) of less than −0.9 dB, −40 dB, and 1.6, respectively, when the input signal was 3.8 GHz. The measured results prove the implemented switch shows the second and third harmonic distortion performances of less than −60 dBm when the input power level and frequency are 25 dBm and 3.8 GHz, respectively. [ABSTRACT FROM AUTHOR]

For the silicon photonics integrated circuits, the optical switch plays a vital role in many applications. Large scale integration requires low switching power and fast switching speed. However the switching time and switching power of silicon thermo-optic switch are typically limited to tens of micro-seconds and tens of milli-watts, respectively. In this paper, we designed and fabricated a silicon thermo-optic switch with spiral optical phase shifters, which can reduce the switching power from 21.5 mW to 8.73 mW compared to the optical switch with straight phase shifters. Furthermore, we optimized the pulse driving, we proposed the calculation formula of the pulse voltage, and the overall quantitative scheme of the pulse voltage and pulse width. By adopting the optimized pulse driving, the switching time is reduced from 27 μs to 4 μs. The proposed silicon thermo-optic switch unit with optimized pulse driving is very promising for the applications where large scale integration of optical switches is needed. [ABSTRACT FROM AUTHOR]

Because local concentration of vacancies in any material is bounded, their motion must be accompanied by nonlinear effects. Here, we look for such effects in a simple model for electric field-driven vacancy motion in a memristor, solving the corresponding nonlinear Burgers’ equation with impermeable nonlinear boundary conditions exactly. We find non-monotonous relaxation of the resistance while switching between the stable (‘on’ and ‘off’) states, and qualitatively different dependencies of switching time (under applied current) and relaxation time (under no current) on the memristor length. Our solution can serve as a useful benchmark for simulations of more complex memristor models.

Static Random-Access Memories (SRAMs) are an integral part of the chip industry, occupying a noticeable share of the memory market due to their high performance and compatibility with CMOS technology. Traditional SRAMs do not have the capacity to retain data after power-off, preventing their use in non-volatile applications. This paper presents a novel Non-Volatile SRAM (NVSRAM) device based on Resistive RAM (RRAM) technology. A comparison between SRAM and the proposed NVSRAM performances is proposed at both cell and memory array level. The comparison covers several metrics such as energy consumption, area and static noise margin (SNM). Moreover, this work proposes a deep analysis of the impact of RRAM variability as well as the CMOS subsystem variability on the NVSRAM performances. The proposed structure demonstrates robust NVSRAM performances in terms of stability and reliability despite RRAM variability. [ABSTRACT FROM AUTHOR]

In the current status, an Adsorption Desalination System (ADS) has been found to have lower water production capacity than conventional desalination technologies. This study proposes a hybrid desalination system integrating the Adsorption (AD) and Open air cycle Humidification-Dehumidification (OHD) process to overcome the challenge of lower water production capacity in ADS. This hybrid system known as AD-OHD system comprises of a single bed ADS and a Humidification-Dehumidification (HDH) unit. The main objective of this work is to analyse the performance of the hybrid AD-OHD system based on parameters such as Gain Output Ratio (GOR) and amount of desalinated water production. The performance of the hybrid AD-OHD system is studied under three different operating conditions of switching (t swt) and sorption time (t spt), namely, t swt > t spt , t swt = t spt , and t swt < t spt. The results indicate that the optimal working condition is achieved when the hybrid AD-OHD system operates at condition t swt < t spt. The amount of desalinated water and GOR under the optimal condition is found to be 1.12 l/h and 0.78, respectively. The study also conducts experimental investigations to evaluate the GOR of the hybrid AD-OHD system under different operating conditions, including the temperature of the water entering the evaporator and the temperature of the hot and cooling water input to the adsorbent bed. Experimental data indicates a positive correlation between GOR and hot water temperatures, while increased cooling water temperature reduce GOR due to reduced adsorption behaviour. Although the evaporator inlet water temperature initially boosts GOR, it declines as the adsorption capacity diminishes. The study highlights the superior performance of the hybrid AD-OHD system compared to both the standalone single-bed ADS and open cycle HDH desalination systems. The hybrid AD-OHD desalination system exhibits an 80 % improvement over the single-bed ADS system and a 50 % improvement over the open cycle HDH system in desalinated water production. Additionally, a theoretical model of the adsorption desalination cycle is developed and validated, demonstrating the viability of the AD-OHD system for desalination applications. • A small scale hybrid adsorption desalination incorporating open air cycle HDH unit. • Amount of desalinated water and GOR of the hybrid AD-OHD system is analyzed. • GOR is found to be 0.78 with desalinated water production of 1.12 l/h. • The hybrid AD-OHD system outperforms the single bed ADS and HDH unit in desalinated water production. [ABSTRACT FROM AUTHOR]

Antiferroelectric liquid crystals (AFLCs) are advanced smart materials for displays with unique properties of tristate switching. Thermodynamic, dielectric and switching characteristics of a room temperature bicomponent AFLC mixture at eutectic composition was investigated in the present work. The emergence of various phases in the eutectic composition was identified on the basis of observed dielectric relaxation modes and other parameters. Critical electric field (E c) to unwind the helix, spontaneous polarization (P s), torsional viscosity (γ t) and switching time (t s) have been determined in the ferroelectric (SmC*) and the antiferroelectric (SmC A *) phases from switching experiments. Spontaneous polarization follows the equation, P s = P o (1-T/T c) γ in the temperature range of tilted chiral smectic phases, with values of T c = 91.8 ± 0.1 °C and γ = 0.410 ± 0.005. Value of γ indicates that the SmA* to SmC* transition is of the first order as observed by the enthalpy measurements from the thermodynamic studies. In the AFLC phase of interest, t s is ∼2–3 ms and P s ∼200 nC/cm2. These parameters suggest that the mixture is appropriate base material for electro-optical applications. [Display omitted] • A wide room temperature AFLC mixture has been formulated. • Mixture possesses paraelectric, ferroelectric & antiferroelectric mesophases. • Relaxation parameters of various modes have been determined. • Polarization, switching time and critical field have been determined. • Mixture competes as an appropriate base material for the smart displays. [ABSTRACT FROM AUTHOR]

This paper deals with the study of dimple type RF MEMS capacitive shunt switch using different meandering techniques for high isolation and low actuation voltage. The novelty of the proposed RF MEMS switch is it incorporates the meanders and dimples, which help to reduce the actuation voltage. The proposed switch structure is optimized, designed, and simulated with FEM analysis such as electromechanical and electromagnetic by using COMSOL and HFSS tools respectively. The best performance of the switch is observed by varying different parameters such as beam material, beam thickness, dielectric thickness, and airgap. The proposed switch with different meandering techniques attains the pull-in voltage in the range of 10.3-46 V, particularly the three uniform meander technique has low actuation voltage of 10.3 V. The RF performance of the device is particularly tuned in the range of 26.5-40 GHz frequency range and it is analyzed for all types of meanders. Among them, the non-uniform single meander has attained the best isolation of -54.13 dB at 40 GHz in the off state. The insertion and return losses of the device are -0.514 dB and -17.35 dB over 1-40 GHz frequency in on state.

This paper illustrates the design, modeling, and analysis of bridge type structure based capacitive RF MEMS switch with different beam thickness and materials. We have used Ashby's approach to select the best materials in each and every level which helped to improve the overall performance of the switch in terms of mechanical, electrical, and RF properties. Silicon Nitride thin film (εr = 7.8) is used as a dielectric material. The beam structure stiffness is analyzed with different materials, such as gold, titanium, and platinum, within these materials gold with high thermal conductivity and Euler-Young's modulus of 77 GPa is offering the best performance. Incorporation of meanders and perforations to the membrane helped to reduce the pull-in voltage. The proposed switch is offering very low pull-in voltage of 1.9 V. The deflection of beam thickness is tabulated for the three materials among them the 2 ţm thickness is best beam thickness for the switch for X-band applications. The switch offers best return loss (S11) of -21.36 dB, insertion loss (S12) of -0.147 dB, and isolation (S21) of -52.04 dB at 8GHz. The switch presented in this paper is preferable in X-band applications.

In this paper, the influence of traps on the dynamic on-resistance ( $\text{R}_{\mathrm{ dson}}$ ) and switching time of AlGaN/GaN high-electron-mobility transistors is validated by means of a switching power converter with floating buck-boost topology. A new scheme based on the voltage-dependent dynamic $\text{R}_{\mathrm{ dson}}$ is proposed to extract the average activation energy of device degradation. The average activation energy obtained is 2.25 eV at 50–200 V and 2.60 eV at 200–600 V. In addition, the dynamic $\text{R}_{\mathrm{ dson}}$ is accurately extracted by a unique extraction circuit with high switching frequency up to 1 MHz and high off-state voltage up to 600 V. Meanwhile, the switching times at turn-on and turn-off transitions are captured in a floating buck-boost converter, showing that the transconductance decreases with increasing drain voltage. Furthermore, the effect of parasitic output capacitor on the dynamic $\text{R}_{\mathrm{ dson}}$ is investigated by an experimental method. Finally, a proper hard operating mode is proposed to alleviate the influence of the trapping effect on the performance of switching power converters.

This paper presents a radio frequency (RF) triple pole triple throw 3P3T cross antenna switch for cellular mobile devices. The negative biasing scheme was applied to improve the power-handling capability and linearity of the switch by increasing the maximum tolerable voltage drop across the drain and source and reverse biasing the parasitic junction diodes. To avoid signal reflection through the antenna in off-state, all the antenna ports were equipped with 50-ohm termination to provide the pull-down path. Considering the simultaneous operation of antenna ports in different switch cases, the presented T-type pull-down path demonstrated improvement of isolation by over 15 dB. Using stacked switches, the 3P3T handled the input power level of over 35 dBm. The chip was manufactured in 65 nm complementary metal oxide semiconductor (CMOS) silicon on insulator (SOI) technology with a die size of 790 × 730 µm. The proposed structure achieved insertion loss, isolation, and voltage standing wave ratio (VSWR) of less than −0.9 dB, −40 dB, and 1.6, respectively, when the input signal was 3.8 GHz. The measured results prove the implemented switch shows the second and third harmonic distortion performances of less than −60 dBm when the input power level and frequency are 25 dBm and 3.8 GHz, respectively.

A room temperature ferroelectric liquid crystal (FLC) mixture has been studied by irradiating with γ-radiation from 60Co source. Important display parameters such as dielectric permittivity, conductivity, spontaneous polarisation, optical tilt angle, rotational viscosity and switching time have been determined as a function of the irradiation dose. Study reveals that transition temperatures involving different phases and optical tilt angle decrease significantly, more at higher doses, which means irradiation decreases the order parameter in different phases. Conductivity increases twelve times probably due to the production of ions or impurities by radiolysis process. Irradiation also affects the dynamics of the molecules manifested by the change in critical frequencies of relaxation modes. Changes in other electro-optic properties suggest that degradation of display quality may not be significant at low γ-radiation exposure but the effect will be severe at high dose. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) was initially designed for prototyping and product personalization, where high production quantities were not required. Now, it is also implemented for final part production to achieve cost-effective mass customization (MC). Thanks to its tool-less production and extreme flexibility, AM has the potential to address individual customer preferences with custom final parts. Nevertheless, despite its increased competitiveness, AM is not yet likely to replace traditional MC systems, but it can complement them, improving manufacturing efficiency. To broaden our understanding of how AM can complement traditional manufacturing systems, we develop an exploratory quantitative model. First, we leverage customer-centricity in a novel time-varying locational choice model of heterogeneous customers, coupling the Bass and the Hotelling–Lancaster models. Then, we investigate customer-centric marketing and operations decisions, exploring technology-switching scenarios that interchange AM with MC across the product life cycle (PLC). We formulate and solve an optimization problem by jointly deciding on technology-switching times, pricing, and product variety strategies to maximize a manufacturer’s profit and meet individual customers’ diverse and evolving needs. We use a validated Sample Average Approximation approach for the numerical solution of our non-convex optimization problem. Testing different pricing strategies, we show that decreasing and flexible trajectories are optimal. We derive analytical properties for the optimal pricing policy and demonstrate that a manufacturer can benefit from interchanging AM and MC across the PLC, in particular by adopting an AM-MC-AM scenario.

A method for achieving the accurate measurement of the antiferroelectric-ferroelectric (AFE-FE) phase switching time based on the electrically induced light scattering effect was designed. The AFE-FE switching times of lanthanum-modified lead zirconate titanate (PLZT) transparent ceramics decreased with the increase of the applied electric fields, and the logarithm of the switching time was approximately proportional to the electric field reciprocal. The random orientation of the polycrystalline structures with dispersion-distributed mixed phases of the PLZT transparent ceramics was the intrinsic mechanism affecting the corresponding switching times in the applied electric field. The smaller electrode size samples switched faster than the larger samples in the same electric field. The size effect of the switching times occurred due to the higher dielectric constant of the ceramics and the parameters of the test circuit, and the larger capacitance of the samples resulted in a longer rising time of the applied electric field, which in turn slowed down the phase switching and prolonged the switching time. [ABSTRACT FROM AUTHOR]

In this paper, an ultra-fast all-optical modulator, based on a new shape of nonlinear photonic crystal ring resonator, is designed and studied. Numerical methods such as plane wave expansion (PWE) and finite-difference time domain (FDTD) are used to perform simulations. The modulation technique consists of carrier light controlling by means of input light signal and Kerr effect. The investigation of extinction ratio and insertion loss within the carrier input power shows that the choice of 0.7 W is the optimal value of that power to ensure the tradeoff between both characteristics. The suggested modulator demonstrates an excellent extinction ratio about 20.8018, a very low insertion loss of −13.98 and a short switching time about 13.4 ps. According to the obtained results, the modulator can be considered as an ultra-fast and ultra-compact optical component. [ABSTRACT FROM AUTHOR]

The impact of the size of silica nanoparticles (SNPs) on the properties of ferroelectric liquid crystals (KCFLC 10R) has been investigated by electro-optical and dielectric techniques. We have found that the doping of silica nanoparticles in the host ferroelectric liquid crystal strongly affects the various properties of doped systems. Doping of silica nanoparticles shows a small decrease in spontaneous polarisation and faster switching time. An improvement in permittivity and conductivity with the temperature at a constant frequency was also noticed after dispersion. This dependence is stronger for large size particles ( ∼ 40 nm) and weaker for small size particles (~12 nm). The Goldstone mode (GM) shifts towards the higher relaxation frequency. These results would be useful to manufacture better optical and electronic devices for display, switching and beam steering applications. [ABSTRACT FROM AUTHOR]

In this study, a novel method is proposed to obtain the minimum elements and a specific sidelobe in time-modulated sparse linear arrays. A genetic algorithm is used to optimise each generation of arrays to reach the required level and range of the sidelobe. Furthermore, the number, arrangement, and switching sequences of the array that satisfy the requirements are obtained. This method provides a scheme to reduce the number of elements using the optimised sparse structure and switching time. However, besides the control of the fundamental component, this method can also be applied to multi-beam forming with the fundamental component and ±first harmonic. Finally, the effectiveness of the proposed method is verified by the simulation and numerical results. [ABSTRACT FROM AUTHOR]

We present a theoretical model in the framework of elastic continuum theory to describe the behaviour of a liquid crystalline host doped with ferroelectric nanoparticles acting as a liquid crystal polarization grating device. The effect of ferroelectric impurity dopants in liquid crystals and the Freedericksz transition is studied. We obtain the critical thickness and voltages of the system and find that, as in the case of pure liquid crystal devices, the critical voltages for weak anchoring conditions would be lower than those in a strong anchoring case. We also investigate the dynamic behaviour of the system and obtain the switching on and off times for the nano-doped cells with strong and weak anchoring conditions on the surfaces. The effects of the flow are excluded in our calculations. The findings show that the rise time of the suspension is lower than that of the pure liquid crystal, and switching times will be prolonged when the anchoring strength is reduced. Our results are consistent with existing experimental reports and may be useful for many applications in the industry. Obviously, electrically control is definitely fundamental in the operation of many liquid crystal devices such as displays, beam steering devices, and liquid crystal modulators. [ABSTRACT FROM AUTHOR]

This paper present the effect on capacitance-voltage (C-V) characteristics of metal-semiconductor-metal (MSM) by Pt doping. Platinum atom dope on back side of substrate and drive in by using rapid thermal annealing (RTA) process around 5 mins, then, diffuse into silicon structure. The influence of doping atom will change structure of silicon and impact to electrical properties of device. Pt atom will induce trapping center in silicon band and will help in switching time of MSM device. The ultimate goal of this paper will focus on C-V characteristics and simulation result of Pt atom to confirm diffusion range. Moreover, we will measure resistance of silicon substrate before and after Pt-doped to confirm diffusion range. [ABSTRACT FROM AUTHOR]

The experimental and simulated switching behavior across the negative differential resistance (NDR) region of GaN/AlN double-barrier resonant tunneling diodes (RTDs) is presented. The shortest 10%–90% experimental switching time was ~55 ps. The experimental results are also studied with P-SPICE circuit models, which show that the relatively low peak-to-valley current ratio (~1.5), relatively high specific contact resistance (≥ 1× 10−6 Ω-cm2), and relatively large specific capacitance limit the switching time. [ABSTRACT FROM AUTHOR]

A two-stage non-standard optimal control problem with time inconsistent preferences is studied. In an infinite horizon setting, a time consistent (sophisticated) decision maker chooses the time of switching between two consecutive regimes. The second regime corresponds to the implementation of a new technology, and a cost must be paid at the switching time. Although the problem is formulated for a general discount function, special attention is devoted to models with nonconstant discounting and heterogeneous discounting. The problem is solved by transforming it into a problem in a finite horizon and free terminal time. The corresponding dynamic programming equations are presented, and conditions for the derivation of the switching time by decision makers with different degrees of sophistication are studied. A resource extraction model with technology adoption is solved in detail. Effects of the adoption of different discount functions are illustrated numerically.