Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Zhi-Ming Yu, Zeying Zhang, Gui-Bin Liu et al.

The past decade has witnessed a surge of interest in exploring emergent particles in condensed matter systems. Novel particles, emerged as excitations around exotic band degeneracy points, continue to be reported in real materials and artificially engineered systems, but so far, we do not have a complete picture on all possible types of particles that can be achieved. Here, via systematic symmetry analysis and modeling, we accomplish a complete list of all possible particles in time-reversal-invariant systems. This includes both spinful particles such as electron quasiparticles in solids, and spinless particles such as phonons or even excitations in electric-circuit and mechanical networks. We establish detailed correspondence between the particle, the symmetry condition, the effective model, and the topological character. This obtained encyclopedia concludes the search for novel emergent particles and provides concrete guidance to achieve them in physical systems.

Jun Ma

Runpan Nie, Hua‐Dong Huang, Dingxiang Yan et al.

The ongoing soft actuation has accentuated the demand for dielectric elastomers (DEs) capable of large deformation to replace the traditional rigid mechanical apparatus. However, the low actuation strain of DEs considerably limits their practical applications. This work developed high-performance polyurethane-urea (PUU) elastomers featuring large actuation strains utilizing an approach of kinetic control over the microphase separation structure during the fabrication process. Additionally, disulfide (DS) bonds were incorporated as dynamic chemical linkages to effectively heal the mechanical damage in the resulting elastomer (PUUDS). Alteration in processing conditions creates notable differences in the rate of phase separation among the multiphase materials. A faster phase separation rate is associated with a reduced degree of microphase separation, increased spacing within hard domains, a higher proportion of disordered hydrogen bonds, and hydrogen bonding index. These changes synergistically improved the electromechanical properties of the PUUDS elastomers, thereby enhancing their actuation performance. The sample processed under the fastest phase separation condition showed the lowest Young's modulus and a pronounced dielectric response at low frequencies. The electrostriction effect accounts for 89% of the total electromechanical coupling, achieving a significant reduction in the driving voltage during actuation. The maximum actuation strain recorded was 21.6% at an electric field of 45 MV/m. Benefiting from the fully reversible dynamic network, the damaged PUUDS elastomer can be healed and restored to its original elongation at break after 3 h at room temperature. Practical application was demonstrated through the development of a miniature butterfly model constructed from a single-layer PUUDS elastomer, showcasing potential applications in soft robotics. These findings highlight the critical role of kinetic control in optimizing the performance of advanced DEs.

Pengrong Lyu, Dirk J. Broer, Danqing Liu

Achieving adaptive behavior in artificial systems, analogous to living organisms, has been a long-standing goal in electronics and materials science. Efforts to integrate adaptive capabilities into synthetic electronics traditionally involved a typical architecture comprising of sensors, an external controller, and actuators constructed from multiple materials. However, challenges arise when attempting to unite these three components into a single entity capable of independently coping with dynamic environments. Here, we unveil an adaptive electronic unit based on a liquid crystal polymer that seamlessly incorporates sensing, signal processing, and actuating functionalities. The polymer forms a film that undergoes anisotropic deformations when exposed to a minor heat pulse generated by human touch. We integrate this property into an electric circuit to facilitate switching. We showcase the concept by creating an interactive system that features distributed information processing including feedback loops and enabling cascading signal transmission across multiple adaptive units. This system responds progressively, in a multi-layered cascade to a dynamic change in its environment. The incorporation of adaptive capabilities into a single piece of responsive material holds immense potential for expediting progress in next-generation flexible electronics, soft robotics, and swarm intelligence. There is significant interest in developing electronic units that can perform sensing, signal processing, and actuation functions independently, similar to biological systems. Lyu et al. develop electronic units based on liquid crystal oligomer networks that exhibit adaptive behavior in response to environmental stimuli such as light and heat.

Yikang Li, Dazhi Wang, Yiwen Feng et al.

Abstract Directional acoustic sensing can be used for localization and detection, has a wide range of applications in various fields, including rescue robotics, drone positioning, and underwater navigation. It is, however, a challenge to sense both the amplitude and direction of the acoustic waves with a simple sensor design. In this paper, a series of artificial cilia is prepared using additive micro‐manufacturing technologies for direction‐sensitive acoustic sensing, including electrospray and 3D micro‐direct ink writing. The response of the artificial cilia at resonance is significantly enhanced, while the resonance frequencies decrease with increasing length, and the response increases due to the amplification. Two resonances are achieved on a cilium by printing two independent electrode‐to‐electrode interconnect bridges. Two signal channels of the artificial cilia produce an ‘8’‐shaped loop by varying acoustic excitation angles, showing that both amplitude ratio and phase difference are direction‐dependent. The two voltages of the artificial cilia can be decoupled to produce different frequencies, amplitudes, and phase differences, thus enabling directional detection of multiple sound sources. The direction‐sensitive acoustic sensing is achieved by micro‐manufacturing artificial cilia. This effort opens an avenue in the fields of cochlear and device detection with promising applications.

Haining Li, Takeshi Kijima, Hiroyasu Yamahara et al.

Abstract A Pb(Zr0.52Ti0.48)O3 (PZT) thin film is fabricated on SrRuO3(SRO)/Pt/ZrO2/Si, and its resistive switching properties are thoroughly investigated. The ZrO2 thin film serves as a buffer layer for the epitaxial growth of single‐crystalline PZT thin films, and spin‐coating fabrication is useful for introducing a suitable defect content to achieve effective resistive switching in PZT. The present PZT thin film exhibits improved ferroelectric properties compared with most of the spin‐coated or sol‐gel prepared PZT films reported previously, with a large saturation polarization of ≈43 µC cm−2 and coercive filed of ≈700 kV cm−1. The symmetrically reversed true‐remanent hysteresis shows no evident imprint effect and a fully saturated polarization is observed. Intrinsic ferroelectric properties indicate the presence of non‐switching components that are conducive to memory applications. Butterfly shaped electrical conduction reveals resistive switching behavior, with abnormal bipolar resistive switching (BRS) at low voltages and normal BRS at high voltages. The abnormal BRS is explained by a microscopic mechanism involving ferroelectric polarization and an induced dipole moment, whereas the normal BRS is studied by fitting different conducting models and is dominated by interfacial barriers and defects. This study presents a progressive strategy for the large‐scale production of ferroelectric perovskite thin films, specifically suitable for silicon‐based memristors.

Julien Bassaler, Jash Mehta, Idriss Abid et al.

Abstract Ultrawide bandgap (UWBG) semiconductors offer new possibilities to develop power electronics. High voltage operation for the off‐state as well as high temperature stability of the devices in on‐state are required. More than AlGaN/GaN heterostructures, AlGaN/AlGaN heterostructures are promising candidates to meet these criteria. Furthermore, the possibility to choose the Al molar fraction of AlGaN paves the way to more tunable heterostructures. In this study, the electronic transport properties of AlGaN channel heterostructures grown on silicon substrates with various aluminum contents, focusing on the temperature dependence of the electron mobility, is investigated. Experimental results from Hall effect measurements are confronted with carrier scattering models and deep level transient spectroscopy analysis to quantify limiting effects. These results demonstrated the significant potential of Al‐rich AlGaN channel heterostructures grown on silicon substrates for high power and high temperature applications.

Sehyeon Choi, Yunseo Lim, Sejin Kim et al.

Abstract As the number of word‐line layers of vertical flash memory increases, it is difficult to develop high aspect ratio contact further. NAND cell scaling can consistently reduce with advanced fabrication development, but the reliability deterioration becomes challenge as the cell‐to‐cell distance decreases. In this study, the hydrogen profile in the SiO2/SiNx/SiO2 (ONO) stack is controlled through post annealing treatment and forming accessible deep level traps. When ONO stack employing with SiNx(x:1.02) is N2‐annealed, Si─Si and Si‐dangling bonds are observed. The polaron effect stemming from the Si─Si bonds led to a reduction in charge loss, thereby maintaining 84% of the memory window (MW). Conversely, when ONO stack employing SiNx(x:1.24) is annealed under forming gas ambient, the MW is increased from 4.68 to 6.57 V. This is attributed to the passivation of interface trap by dissociating N─H bonds and alleviating charge retention by reduction in the density of Si‐dangling bond, leading to maintaining 89.7% of MW. These results address the reliability issue caused by trapped‐charge instability and successfully mitigate the trade‐off relation between MW and retention characteristics.

Jens Werner, Alexandra Burger, Sebastian Koj

This paper presents a project-based learning (PBL) approach to provide students with an in-depth understanding of the concept of capacitive coupling. Capacitive coupling, among other coupling mechanisms, is of fundamental importance in the analysis of electromagnetic interference (EMI) problems and thus part of electromagnetic compatibility (EMC). It is fundamentally based on the interaction of three-dimensionally distributed alternating electric fields between several conductive structures. For simple geometries, it can be described by integrated quantities voltage, charge and capacitance and be modeled using equivalent circuit diagrams. For complex geometries, numerical simulation tools are typically used. In the project idea presented here, the spatial field distribution is firstly calculated and visualized using 3D EM simulation software. Parametric simulations are then used to develop discrete equivalent circuits that describe the behavior in a simplified way using the integral variables described above. An analytical description based on geometry and material data is compared with the numerical results. Finally, the simulated structure is built by students as a real structure and measured using a vector network analyzer (VNA). The students can compare and validate their results with the data they have collected themselves.Over the course of a semester, students work on this project, which deals with the above-mentioned research topic. They use different methods and learn to compare and evaluate their results. In this way, students develop a deeper understanding of the content as well as critical thinking, collaboration, creativity and communication skills. PBL can thus unleash a stimulating, creative energy in both students and teachers.

Philip Kitson, Wayne J. Chetcuti, Gerhard Birkl et al.

We present the operating principle of a quantum sensor for electric fields based on networks of Rydberg atoms. The sensing mechanism exploits the dependence of the Rydberg blockade on the electric field, particularly in the vicinity of the Förster resonance - the electric field can be measured through the variation in the size of the blockade radius across the network of Rydberg atoms. Specifically, we track the dynamics of Rydberg excitations in systems of various spatial structures, subjected to different electric field configurations, to monitor the connection between the field and blockade. We also use the density-density correlator to analyse spatially varying (inhomogeneous) electric fields and relate these correlators to the applied fields.

Harry Walden, Alexander Stegmaier, Jörn Dunkel et al.

Non-reciprocal interactions in elastic media give rise to rich non-equilibrium behaviors, but controllable experimental realizations of such odd elastic phenomena remain scarce. Building on recent breakthroughs in electrical analogs of non-Hermitian solid-state systems, we design and analyze scalable odd electrical circuits (OECs) as exact analogs of an odd solid. We show that electrical work can be extracted from OECs via cyclic excitations and trace the apparent energy gain back to active circuit elements. We show that OECs host oscillatory modes that resemble recent experimental observations in living chiral crystals and identify active resonances that reveal a perspective on odd elasticity as a mechanism for mechanical amplification.

Tomaž Podobnik

The electric current as the flux of current density -- a signed scalar, not a vector -- is inconsistent with the concept of the current direction, commonly invoked in the electric circuit analyses within, for example, Kirchhoff's current law, the resistance rule, and Lenz's law. This paper presents an approach to the circuit analysis that is not predicated upon the ``current direction,'' and thus avoids such inconsistencies. The approach is summarized in five rules and the application of these rules is demonstrated by analyzing an RLC series circuit.

K. Sakthisudhan, N. Saranraj, V. R. Vinothini et al.

Chatchai Chokchai, Yoshiki Sugimoto, Kunio Sakakibara et al.

This paper proposes a broadband single-ended line-to-waveguide transition that covers the 240&#x2013;300 GHz band. The transition comprises a tapered grounded coplanar waveguide (GCPW) feed line, inserted from the narrow wall of the waveguide exciting a modified V-shaped patch located at the center of the waveguide. Broadband operation is achieved via multiple resonances of the modified V-shaped patch, a double-stacked rectangular patch, and cavity within the multi-layer substrates. The transition geometries are optimized via electromagnetic simulations using the finite element method. The transition design is successful within fabrication limitations in the terahertz frequency band. Subsequent evaluations of transition performance are conducted through measurements and simulations. Experimental results show a bandwidth below &#x2212;10 dB for <italic>S</italic>₁₁ spanning 71.5 GHz. Furthermore, the measured insertion loss remains consistent at 2.5 dB at the center frequency of 275 GHz.

Mila Lewerenz, Elias Passerini, Luca Weber et al.

Abstract The human brain facilitates information processing via generating and receiving temporal patterns of short voltage pulses, a.k.a. neural spikes. This approach simultaneously grants low‐power operation as well as a high degree of noise immunity and fault tolerance at a small footprint and simplistic structure of the neurons. To date, the latter two key features are critically missing from the toolbox of artificial spiking neural network hardware, hindering the development of scalable and sustainable artificial intelligence (AI) platforms. Here, a compact, gate‐tunable neuron circuit is demonstrated, and its potential as a functional leaky integrate‐and‐fire (LIF) neuron is explored. It relies on a single nanoscale three‐terminal (3T) memristor device, which has been downscaled by 30% compared to previous work, where the set voltage and, thereby, the spiking probability of the neuron circuit can be widely tuned by the low‐voltage operation of the gate electrode. The influence of the gate voltage on the two‐terminal (2T) current–voltage characteristics is measured, statistically analyzed, and further utilized in a custom‐built LTspice model. The circuit simulations account for the experimentally observed, adjustable set voltage. The presented results demonstrate the merits of 3T memristors as compact, tunable, and versatile artificial neurons for neuromorphic computing applications.

Longzhen Wang, Qian Zhao, Chunhui Miao et al.

This study evaluates the effectiveness of GN (Graphene Nanoplatelets) salt inhibitor-treated concrete in inhibiting chloride ion diffusion and corrosion compared to untreated concrete under various erosion conditions. Through an accelerated indoor chloride erosion test lasting 180 days, we examined the temporal changes in internal chloride ion concentration with and without the GN salt inhibitor. Quantitative assessment of the inhibitor's impact was achieved by introducing reduction factors for surface chloride concentration and diffusion coefficient. Our findings reveal a significant reduction of 31.3 % in chloride ion diffusion coefficient and 22.67 % in surface chloride concentration in concrete treated with GN salt inhibitor. This indicates the inhibitor's potential to extend the service life of gearbox and substation foundations exposed to chloride ion erosion environments.

Yujing Duan, Yupeng Zhang

Smart Grids are constructed using control, networking, and advanced computing technologies. Malicious attacks are still a possibility for the grid, although there are now insufficiently fast and accurate detection methods. Cybercrimes affecting the security of the smart grid include the compromise of vital client data by attackers, the spread of viruses, cybersecurity mistakes, and vulnerabilities in distributed systems. In order to provide security in a smart grid context, a SMART (Smart Attack detectoR Technique) framework is developed in this paper. The attacker first sends the request to the risk identification, which will identify the request's original source. Risk estimation calculates the degree of risk and gives processing decisions. Following that, word embedding is used to complete the pre-processing. Information will be prohibited if the process is found to be too vulnerable according to CNN-BiLSTM categorization criteria. The data will be sent to the smart grid automatically if the procedure is low vulnerable and there is no assault. A MATLAB simulator is used to implement the suggested approach. In comparison to the presently used CNN-LSTM [10], SCADA [13], and GOOSE [14] approaches, which have success rates of 19.09 %, 32.22 %, and 57.47 %, respectively, the experimental findings indicate that the suggested SMART strategy has a 99 % success rate, which is very high.

Xuan Dong, Siew Yin Chan, Ruoqing Zhao et al.

Abstract Given the widespread presence of intricate surfaces, the development of electronics has generated a significant demand for surface patterning techniques capable of creating refined or novel patterns. Nevertheless, present surface patterning techniques suffer from complex processes, limited resolution, stringent conditions, and high manufacturing costs. Herein, we present a novel approach for arbitrary surface micropatterning using photosensitive polyimide (PSPI), enabling the in situ fabrication of electrodes without the need for a pattern‐transferring process. On this basis, we have implemented a high‐performance, freestanding flexible thin‐film mask with high optical transparency that facilitates precise alignment of microelectrode patterns with the target material. It also exhibits exceptional mechanical properties suitable for long‐term use and high‐temperature applications, with a notable glass transition temperature of up to 300°C. The fabricated masks with thicknesses of 5–20 μm are well‐suited for high‐resolution applications, including those requiring sub‐5 μm resolution. Furthermore, the creation of microelectrodes on a variety of surfaces utilizing the fabricated PSPI masks was successfully demonstrated. Our facile method provides a solid foundation for achieving efficient micropatterning for the fabrication of high‐performance flexible electronics on complex surfaces.

Theodore Modis

The main advantage of electric vehicles, namely, their non-polluting operation, is compromised when the electricity they use comes from burning fossil fuels. The number of electric vehicles on the road is growing much faster than the amount of green electricity produced. It is forecasted that in 2037 the number of electric vehicles on the road will need an amount of electricity equal to the entire green electricity produced at that time. Therefore, green operation of electric vehicles entering the market after 2037 will be impossible. The sales of hydrogen-burning vehicles are poised to overtake the sales of electric vehicles in 2041, but a non-polluting overall operation for them is not guaranteed either at this time.

Avinash Kumar Gupta, Mani Shankar Yadav, Brajesh Rawat

Memristor-based crossbar architecture emerges as a promising candidate for 3-D memory and neuromorphic computing. However, the sneak current through the unselected cells becomes a fundamental roadblock to their development, resulting in misreading and high power consumption. In this regard, we theoretically investigate the Pt/Ti/NbO2/Nb2O5−x/Pt-based self-selective memristor, which combines the inherent nonlinearity of the NbO2 switching layer and the non-volatile operation of the Nb2O5−x memory layer in a single device. The results show that the Pt/Ti/NbO2/Nb2O5−x/Pt-based self-selective memristor offers the sneak current of 310 nA, selectivity of around 174, and on/off current ratio of 75, compared to the sneak current of approximately 70 μA, selectivity of about 4.02, and on/off current ratio of around 1.55 for the Pt/Ti/Nb2O5−x/Pt-based memristor device. Our self-selective memristor minimizes the sneak current, but a small on/off current ratio limits their readout margin and power efficiency for crossbar array size greater than 4KB. Further, we demonstrate that breaking down a large-scale crossbar array into smaller subarrays and separating them by transistor switches, called the split crossbar array, is a more efficient way of achieving a practical size crossbar array with improved readout margin and power efficiency. Our results shed light on the potential of the Pt/Ti/NbO2/Nb2O5−x/Pt-based self-selective memristor and explore the split crossbar array architecture as a practical solution to augment readout margins and power efficiency in a large-scale crossbar array.