Nonlinear Resistance Research Articles

A new S-box pattern generation based on chaotic enhanced logistic map: case of 5-bit S-box

AbstractCryptography plays consistently an essential role in securing any sort of communications or data broadcast over the network. Since the security of any designed block cipher algorithm is related to its Substitution box (S-box), several efforts have been made by researchers to design a vigorous S-box that maintains flawlessly the cost, performance, and security trade-off. From the literature, we can find a variety of input–output sizes of S-boxes, each of which has its benefits and drawbacks. Therefore, this work introduces a new S-box pattern generation based on the chaotic enhanced logistic map where its chaotic behavior offers good randomness ability, a fact that enhances its unpredictability. In our realization, the intention was the generation of a 5-bit Sbox due to its suitability and cost-effectiveness to be integrated into lightweight cryptosystems. Moreover, the S-box security strength is proved by testing it through numerous cryptanalysis measurements. We can mention non-linearity, bijectivity, linearity, differential cryptanalysis, boomerang attacks resilience, Avalanche effect, and algebraic attacks resilience. The results show that our proposition provides good resistance to the aforementioned attacks and even shows superiority over its 5-bit competitors in terms of non-linearity, differential, Boomerang, and algebraic attack resistance.

The Impact of Non‐Monolithic Semiconductor Capacitance on Organic Electrochemical Transistors Performance and Design

AbstractThe existing device models for organic electrochemical transistors (OECTs) fail to provide any device design guidelines for optimized performance parameters such as transconductance that are pivotal for the applications OECTs in sensing. Moreover, the current models are based on the questionable assumption of a homogenous organic semiconductor layer, and all predict a linear behavior of the resistance with the OECT channel length. Consequently, the experimentally observed nonlinear resistance behavior in OECTs has been overlooked thus far. Here, an OECT device model is developed that accurately describes the nonlinear behavior of the OECT channel resistance and offers the first guidelines for maximizing transconductance. The model is inherently nonlinear and the nonlinearity stem from the non‐monolithic capacitance of the organic semiconductor layer. Moreover, the model provides a consistent and reliable estimations for the contact resistance in OECTs. The success of the model in accurately describing and providing predictions of the OECT operation by relating the device's geometrical parameters with electrochemical parameters of the semiconductor layer paves the way toward unlocking OECT potentials in diverse applications, from biosensing to neuromorphic computing and flexible electronics.

A novel Chua's based 2-D chaotic system and its performance analysis in cryptography.

In this study, the chaotic behavior of a second-order circuit comprising a nonlinear resistor and Chua's diode is investigated. This circuit, which includes a nonlinear capacitor and resistor among its components, is considered one of the simplest nonautonomous circuits. The research explores various oscillator characteristics, emphasizing their chaotic properties through bifurcations, Lyapunov exponents, periodicity, local Lyapunov region, and resonance. The system exhibits both stable equilibrium points and a chaotic attractor. Additionally, the second objective of this study is to develop a novel cryptographic technique by incorporating the designed circuit into the S-box method. The evaluation results suggest that this approach is suitable for secure cryptographic applications, providing insights into constructing a cryptosystem for images and text based on its complex behavior. Real-life data were analyzed using various statistical and performance criteria after applying the proposed methodology. These findings enhance the reliability of the cryptosystems. Moreover, The proposed methods are assessed using a range of statistical and performance metrics after testing the text and images. The cryptographic results are compared with existing techniques, reinforcing both the developed cryptosystem and the performance analysis of the chaotic circuit.

Ex vivo evaluation of the whole heart function allowing selective investigation of the right and left heart

Objectives. The aim was to demonstrate a reliable ex vivo method to test the function of the whole heart. Design. Pigs of varying sizes (44–80 kg) were exposed to dose response of adrenaline. Blood pressures and cardiac output were measured. The explanted hearts were tested in a novel ex vivo system to see if we could replicate the in vivo values at maximal adrenaline stimulation. The perfusion solution was STEEN Solution™ with erythrocytes and continuous infusion of essential drugs. In contrast to normal body circulation which is sequential, the heart evaluation system is divided into left and right heart circuits which are operating in parallel, making it possible to test the right and left heart individually or as a whole. The system provides coronary flow measurements. The nonlinear dynamic resistances are constructed to stabilize systolic and diastolic pressures in a broad range and independently from cardiac output. It is important for the functional evaluation to avoid pumping help for the heart; therefore, atrial vortexes are constructed to minimize pump flow directionality and energy from entering atria. Results. Ex vivo evaluation was able to match the maximal in vivo effect of adrenaline on cardiac output and blood pressures. After 2 h of evaluation, the blood gases and lactate were normal and free haemoglobin was zero. Autopsy of the hearts showed no macroscopic pathology. Conclusions. The system is able to give a reliable functional evaluation of the heart ex vivo.

Nonlinear electronic devices on single-layer CVD graphene for thermistors

In this article, we present simple, cost-effective, passive (non-gated) electronic devices based on single-layer (SL) chemical vapor deposited (CVD) graphene that show nonlinear and asymmetric current-voltage characteristics (CVCs) at ambient temperatures. Al2O3-Ti-Au contacts to graphene results in a nonlinear resistance to achieve nonlinearity in the CVC. Upon transfer to polyethylene terephthalate, the CVD-grown SL graphene shows mobility of 6200 cm2V-1S-1. We have observed both thermoelectric effect and thermoresistive sensing in the fabricated devices such as voltage and temperature concerning change in electronic power and resistance through asymmetric and nonlinear CVC. The device is stable both at low and high voltages (±200 mV to ±4 V) and temperatures (4 K - 300 K). Graphene-based thermosensing devices can be ultra-thin, cost-effective, non-toxic/organic, flexible, and high-speed for integration into future complementary metal-oxide semiconductor (CMOS) interface, and wearable self-power electronics. A strong negative temeperature coefficent of resistance is demonstrated in the realized nonlinear graphene-integrated resistors for its application in NTC thermistors.

MODELING OF SYSTEMS WITH THE PHOTOVOLTAIC POWER SOURCE AND WATER PUMPS

The article is devoted to the calculation of systems consisting of a solar photovoltaic power source and water pumps. It is noted that such systems can be used both in households or industry, and in agriculture, in particular for irrigation. Several variants of water pumps are shown. An analysis of the operational modes where the photovoltaic power source is connected to the pump has been carried out. The selection of equipment was carried out and the expediency of using a system with an electric energy booster was indicated. A booster for providing current during start-up modes can be a capacitor, a battery of capacitors or an ionistor. Emphasis is placed on the fact that for doing of such systems it is necessary to apply modeling with the use of electrical models. It is shown that for developing of electric models of solenoid-based pumps and pumps based on rotating direct current motors, it is necessary to use the methods of electromechanical analogies. Electrical models of a photovoltaic power source and, based on analogies, a solenoid-based pump and a direct current motor-based pump with permanent magnet excitation and parallel excitation were developed. When developing electrical models, controlled sources of voltage and current were used with mutual influence of the electrical and mechanical parts of the pumps. The need to use direct current motors with parallel excitation is indicated, as they are more stable to emergency modes. It is also stated that in general, the mechanical load of the rotating part of motors is non-linear and depends on the number of revolutions of the shaft. A nonlinear resistance that models a nonlinear mechanical load is shown, and it is noted that the higher-order nonlinearity is insignificant. Conclusions are drawn and further development in the direction of the use of digital technologies is outlined.

Coherence resonance in a memristive map neuron and adaptive energy regulation

Involvement of memristive term and additive physical variables including magnetic flux and charge can enhance the physical description of the biophysical neurons. Neural circuits coupled with memristors can be built and tamed to mimic the intrinsic biophysical characteristics and dynamical properties of biological neurons, and these memristive oscillator models are effective in predicting the mode transition in neural activities and self-organization in collective electric behaviors of neural networks. Any proposal of memristive map neurons requires reliable physical description. For example, the energy definition and self-adaptive working mechanism are crucial to verify the reliability of memristive maps. A capacitive variable is useful to describe the membrane potential, while the complexity of ion channels requires careful evaluation and description by using inductive variables relative to the electromagnetic field. In this work, a charge-controlled memristor is connected to an inductor in series for building a hybrid ion channel, and then a capacitor and a nonlinear resistor are combined to couple the ion channel. As a result, a simple memristive neural circuit is designed to discern the inner effect of electric field and magnetic field synchronously. The energy function is defined and verified with theoretical proof. Furthermore, a linear transformation is applied to convert this memristive neuron into a memristive map with an exact energy description, in which its dynamics and mode transition will be controlled by an adaptive law when its energy is beyond the threshold. Additive noise is imposed to induce coherence resonance, which can be detected by using the statistical analysis and average value for Hamilton energy function during changes in noise intensity. This scheme provides guidance for energy definition in memristive maps and the intrinsic energy regulation mechanism in neural activities is explained from physical and dynamical aspects.

Enhancing voltage regulation in high-speed digital circuits: A simulation-based analysis of the modified Ohm's law

Voltage droop is a significant challenge in high-speed digital circuits, impacting the reliability and performance of electronic systems. This paper introduces a novel approach based on a Modified Ohm's Law to address this issue. By incorporating nonlinear resistance effects, the Modified Ohm's Law provides a more accurate representation of circuit behavior, particularly under dynamic conditions. Through a rigorous simulation framework, the behavior of power supply models under varying load conditions is analyzed. The paper systematically examines circuit responses, load variations, and power supply dynamics, integrating both Standard and Modified Ohm's Law to compare their effectiveness in voltage regulation. The simulation results indicate that the Modified Ohm's Law provides a more accurate prediction of voltage behavior, particularly under rapid load changes, leading to significant improvements in voltage stability. The applied parameter sweep analyses reveal that adjusting the time constant of the power supply within the Modified Ohm's Law framework yields superior voltage regulation compared to traditional methods. Additionally, the analysis of frequency and amplitude variations demonstrates the robustness of the Modified Ohm's Law in maintaining voltage stability across different operational scenarios. This approach effectively addresses the nonlinearities in resistance, reducing voltage droop and enhancing the reliability of high-speed digital circuits. The findings demonstrate the potential of the Modified Ohm's Law in practical applications, suggesting further research and real-world experimentation to fully explore its benefits and implementation strategies. This work contributes to the advancement of voltage regulation techniques, offering a robust solution to the persistent problem of voltage droop in modern electronic systems.

Nonlinear global design resistance: Case studies of post‐tensioned concrete bridges made of I‐73 and KA‐61 girders

Nonlinear global design resistance: Case studies of post‐tensioned concrete bridges made of <scp>I</scp>‐73 and <scp>KA</scp>‐61 girders

Mean-field backward stochastic differential equations with mean reflection and nonlinear resistance

The present paper is devoted to the study of the well-posedness of mean field BSDEs with mean reflection and nonlinear resistance. By the contraction mapping argument, we first prove that the mean-field BSDE with mean reflection and nonlinear resistance admits a unique deterministic flat local solution on a small time interval. Moreover, we build the global solution by introducing a two-step approach, which is a combination of stitching method and fixed point method. We further provide an application to the super-hedging problem with risk constraint.

A memristive map neuron under noisy electric field

From a neural circuit to a biophysical neuron model, standard scale transformation requires the combination of physical variables including capacitance and resistance associated with a capacitor C and a resistor R, respectively. The voltage across the capacitor is used to mimic the membrane potential for neurons. Therefore, most of the neuron models contain one or two capacitive variables for the membrane potential. In fact, the reference time scale (RC) can be replaced by combinating parameters for inductor and resistor during approach of scale transformation for physical variables in the neural circuit. In this study, a simple nonlinear circuit is built by applying two inductors, a charge-controlled memristor (CCM), a nonlinear resistor and a resistor. The circuit equations are derived to develop a memristive oscillator with exact description of energy function. Furthermore, an equiavlent memristive map is obtained by applying linear transformation on the sampled variables from the memristive oscillator. The Hamilton energy function for memristive oscillator is calculated by using the Helmholtz's theorem, and then the memristive map is given in energy function in discrete form. The memristive map has rich dynamic characteristics and can identify coherence resonance under applying noisy electric field. This scheme will provide a theoretical guidance for building nonlinear circuits and maps without using capacitors.

From 2008–2011 Great Recession to COVID-19 pandemic: an analysis of resilience metrics in European regions

AbstractWe aim to clarify the usefulness of different measures of economic resilience in the context of global shocks. In relation to the Great Recession, Oil&amp; European migrant crises, and COVID-19, we compute and validate from a statistical point of view, then characterize five metrics on 317 NUTS2 regions and 21 years. ROC curves and Cox regression compare them by the capacity to predict the post-shock state. Heterogenous behavior characterizes resistance, recovery, and loss. Furthermore, the non-linear resistance performs best in future state prediction, while the composite index has the lowest efficiency as a predictor of the regions’ recovery.

Frequency Analysis of Gas Discharge Based Memristor Emulator for Ferroresonance

The nonlinear resistance for suppression of ferroresonance modes can be realized using memristive circuits. Based on voltage requirement, gas discharge memristive circuit has been chosen. As a primary requirement, the nonlinear characteristics of memristive circuit have been investigated in this work. The memristive nature at all chosen frequencies are analyzed interms of hysteresis nature. The suitability of chosen circuit against all modes of ferroresonance is identified interms of nonlinear index and memductance values obtained using Simulink. The nonlinear index with respect to symmetrical hysteresis response decreases as the frequency increases. The memductance has been calculated to verify the load requirement under the ferroresonance frequencies. As the frequency increases, the memristive emulator loses its symmetry gradually from fundamental frequency.

Are There an Infinite Number of Passive Circuit Elements in the World?

We found that a second-order ideal memristor [whose state is the charge, i.e., in ] degenerates into a negative nonlinear resistor with an internal power source. After extending analytically and geographically the above local activity (experimentally verified by the two active higher-integral-order memristors extracted from the famous Hodgkin–Huxley circuit) to other higher-order circuit elements, we concluded that all higher-order passive memory circuit elements do not exist in nature and that the periodic table of the two-terminal passive ideal circuit elements can be dramatically reduced to a reduced table comprising only six passive elements: a resistor, inductor, capacitor, memristor, mem-inductor, and mem-capacitor. Such a bounded table answered an open question asked by Chua 40 years ago: Are there an infinite number of passive circuit elements in the world?

Prospects of silicide contacts for silicon quantum electronic devices

Metal contacts in semiconductor quantum electronic devices can offer advantages over doped contacts, primarily due to their reduced fabrication complexity and lower temperature requirements during processing. Some metals can also facilitate ambipolar device operation or form superconducting contacts. Furthermore, a sharp metal–semiconductor interface allows for contact placement in close proximity to the active device area avoiding damage caused by dopant implantation. However, in the case of gate-defined quantum dots in intrinsic silicon, the formation of a Schottky barrier at the silicon–metal interface can lead to large, nonlinear contact resistances at cryogenic temperatures. We investigate this issue by examining hole transport through metal oxide-semiconductor transistors with platinum silicide contacts on intrinsic silicon substrates. We extract the contact and channel resistances as a function of temperature and improve the cryogenic conductance of the device by more than an order of magnitude by implementing meander-shaped contacts. In addition, we observe signatures of enhanced transport through localized defect states, which we attribute to platinum clusters in the depletion region of the Schottky contacts that form during the silicidation process. These results showcase the prospects of silicide contacts in the context of cryogenic quantum devices and address associated challenges.

A method to design a fast chaotic oscillator using CCTA

This article introduces a novel method for designing a fast chaotic oscillator using a CCTA (Current Conveyor Transconductance Amplifier) based on Chua's circuit. The proposed method uses innovative configurations and advanced simulation techniques to overcome challenges in high-speed operation, nonlinear dynamics, and Analog Building Block (ABB) selection. The design begins with nonlinear negative resistance, essential for Chua's diode characteristics, including two negative resistances, NR1 and NR2. The circuit integrates one CCTA block, two grounded capacitors, two fixed resistors, one inductor, and one potentiometer. It is simulated using PSPICE with IC (Integrated Circuit) macro-models and 180nm CMOS (Complementary Metal Oxide Semiconductor) technology. Various chaotic waveforms and attractors are produced, validating the theoretical and mathematical predictions. By varying the resistance values (1450Ω, 1650Ω, 1800Ω, 1950Ω), the circuit exhibits different chaotic behaviors, such as large limit cycles, double-scroll attractors, Rossler-type attractors, and I-periodic attractors. FFT (Fast Fourier Transform) analysis confirms the highest dominant operating frequency of 37.5MHz. A Monte Carlo simulation with 100 runs shows maximum voltage variations in the chaotic waveforms of 5.21 % and 4.61 % across the capacitors, demonstrating robustness and reliability. This design offers significant advancements in implementing high-frequency chaotic oscillators, with potential applications in various fields requiring chaotic signal generation.•A novel design of Chua's diode and Chua's chaotic oscillator using only one CCTA block is presented in this paper.•The proposed chaotic oscillator achieves the highest operating frequency of 37.5MHz.•The proposed circuit is simulated using commercially available ICs (MAX435 and AD844) and CMOS 180nm technology in PSPICE to confirm its workability.

Modeling Excitable Cells with Memristors

This paper presents an in-depth analysis of an excitable membrane of a biological system by proposing a novel approach that the cells of the excitable membrane can be modeled as the networks of memristors. We provide compelling evidence from the Chay neuron model that the state-independent mixed ion channel is a nonlinear resistor, while the state-dependent voltage-sensitive potassium ion channel and calcium-sensitive potassium ion channel function as generic memristors from the perspective of electrical circuit theory. The mechanisms that give rise to periodic oscillation, aperiodic (chaotic) oscillation, spikes, and bursting in an excitable cell are also analyzed via a small-signal model, a pole-zero diagram of admittance functions, local activity, the edge of chaos, and the Hopf bifurcation theorem. It is also proved that the zeros of the admittance functions are equivalent to the eigen values of the Jacobian matrix, and the presence of the positive real parts of the eigen values between the two bifurcation points lead to the generation of complicated electrical signals in an excitable membrane. The innovative concepts outlined in this paper pave the way for a deeper understanding of the dynamic behavior of excitable cells, offering potent tools for simulating and exploring the fundamental characteristics of biological neurons.

Control of microstructure to prepare compressible graphene aerogel via ice template

The microstructure of graphene aerogel (GA) plays a crucial role in determining its performance. However, challenges persist in simplifying and enhancing control over the microstructure of GA. In this study, we introduce a novel bidirectional freeze-casting method, allowing for the preparation of GAs with three different microstructures. Notably, the GA with concentric ring structure exhibits exceptional compressibility and fatigue resistance in both axial and radial directions, capable of undergoing 5000 compression-recovery cycles at 90 % strain and 70 % strain, respectively. In-situ SEM characterization provides insights into the energy dissipation mechanism during compression processes. GA with radial microstructure demonstrates an impressive absorption capacity ranging from 165.82 to 369.47 g/g. Moreover, the GA with concentric ring microstructure displays non-linear resistance changes with strain under both axial and radial compression. These GAs demonstrate significant potential applications in environmental remediation and flexible electronics.

Enhanced emergent electromagnetic inductance in Tb5Sb3 due to highly disordered helimagnetism

In helimagnetic metals, ac current-driven spin motions can generate emergent electric fields acting on conduction electrons, leading to emergent electromagnetic induction (EEMI). Recent experiments reveal the EEMI signal generally shows a strongly current-nonlinear response. In this study, we investigate the EEMI of Tb5Sb3, a short-period helimagnet. Using small angle neutron scattering we show that Tb5Sb3 hosts highly disordered helimagnetism with a distribution of spin-helix periodicity. The current-nonlinear dynamics of the disordered spin helix in Tb5Sb3 indeed shows up as the nonlinear electrical resistivity (real part of ac resistivity), and even more clearly as a nonlinear and huge EEMI (imaginary part of ac resistivity) response. The magnitude of the EEMI reaches as large as several tens of μH for Tb5Sb3 devices on the scale of several tens of μm, originating to noncollinear spin textures possibly even without long-range helimagnetic order.

Optimal permeance ratio, flux direction and layer distribution in composite asymmetric membranes composed of sequences of layers obeying real-power flux laws

In this study, the optimal permeance ratio and layers distribution in multilayer membranes and thin films in which each layer obeys the following real-power law: Flux=πi(P1,ini−P2,ini) are determined for any positive real values of ni. Such an exponent has a physical meaning in several cases, such as: diffusion-controlled permeation of hydrogen in metal membranes i) under infinite-dilution conditions (n = 0.5), and ii) under higher-concentration ones (0.5 < n < 1.5), iii) desorption-limited permeation (n = 1) in the same type of membranes, Knudsen-type diffusional mechanism (n = 1) and viscous flow (n = 2) in microporous membranes. Furthermore, n is equal to 4 in radiation-driven thermal flux. The work considers two generic layers of different thicknesses and exponents, for which it is proven the existence of a general optimal permeance ratio π1/π2 maximising the flux ratio, which is found to be equal to the inverse of the ratio between the respective maximum theoretical driving forces that can be established in each layer. Such an optimal permeance ratio is also proven to be a global optimum. Afterwards, we provide a theoretical generalisation of this optimality to whatever types of driving forces. Then, we provide a demonstration that the highest species permeating flux is always established when feeding it from the layer side with the highest exponent independently of the permeance ratio. As an important consequence, to maximise flux, a multilayer membrane/thin film should be fabricated by depositing the layers in cascade according to the ascending or descending exponents, and should be used in a configuration in which the flux flows from the layer with the highest pressure exponent to the layer with the lowest one. It is also shown that there exists an optimal value of the lower exponent n1 that maximizes the flux ratio keeping constant the other parameters. Finally, we showed that a virial-type linear combination of polynomial driving forces can be approximated by the empirical flux law investigated. Overall, our results are valid not only for whatever type of composite membranes and thin films (metallic, ceramic, polymeric and hybrid ones), but also for any sequential system involving a flux of whatever physical entity obeying the aforementioned law, such as heat transfer in the presence of radiation, non-linear electrical resistances and possible others.