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

Eugene A. Eliseev, Anna N. Morozovska, Sergei V. Kalinin et al.

ABSTRACT Proximity ferroelectricity is a novel paradigm for inducing ferroelectricity in a non‐ferroelectric polar material, such as AlN or ZnO that are typically unswitchable with an external field below their dielectric breakdown field. When placed in direct contact with a thin switchable ferroelectric layer (such as Al1‐xScxN or Zn1‐xMgxO), they become a practically switchable ferroelectric. Using the thermodynamic Landau‐Ginzburg‐Devonshire theory, in this work, we perform the finite element modeling of the polarization switching in the compositionally graded AlN‐Al1‐xScxN, ZnO‐Zn1‐xMgxO, and MgO‐Zn1‐xMgxO structures sandwiched in both a parallel‐plate capacitor geometry as well as in a sharp probe‐planar electrode geometry. We reveal that the compositionally graded structure allows the simultaneous switching of spontaneous polarization in the whole system by a coercive field significantly lower than the electric breakdown field of unswitchable polar materials. The physical mechanism is the depolarization electric field determined by the gradient of chemical composition “x”. The field lowers the steepness of the switching barrier in the otherwise unswitchable parts of the compositionally graded AlN‐Al1‐xScxN and ZnO‐Zn1‐xMgxO structures. In the MgO‐like regions of the compositionally graded MgO‐Zn1‐xMgxO structure, a shallow double‐well free energy potential emerges. Proximity ferroelectric switching of the compositionally graded structures placed in the probe‐electrode geometry occurs due to nanodomain formation under the tip. We predict that a gradient of chemical composition “x” significantly lowers effective coercive fields of the compositionally graded AlN‐Al1‐xScxN and ZnO‐Zn1‐xMgxO structures compared to the coercive fields of the corresponding multilayers with a uniform chemical composition in each layer. A tip‐induced switching further lowers the coercive field, enabling control of ferroelectric domains in otherwise unswitchable compositionally graded structures, which can provide nanoscale domain control for memory, actuation, sensing, and optical applications.

Fakhrul Zaman Rokhani, Mircea R. Stan, Maurizio Palesi et al.

The explosive growth of AI workloads elevates on-chip communication and heat dissipation to first-order constraints. This survey paper consolidates thermal-aware Network-on-Chip (NoC) design for AI computing across tools, algorithms, and applications. Concretely, we first assemble a reproducible toolchain that couples cycle-accurate NoC simulators with power/thermal solvers and machine-learning surrogates for fast temperature prediction. We then structure the design space along three design dimensions: sensing strategies, control methodologies, and thermal- and traffic-aware data delivery. Finally, we close the loop among traffic, power, and temperature via an integrated co-simulation workflow, providing practical guidelines for thermal-aware NoC-based AI accelerator designs. Unlike general DNN-accelerator surveys, this survey paper focuses on the thermal–NoC interplay under realistic AI workloads and provides an actionable, closed-loop methodology and tooling for scalable, verifiable evaluation. We conclude with open challenges, scalable yet faithful co-simulation, standardized traces/interfaces, packaging-aware models, and uncertainty-aware surrogates, to guide the path toward thermally resilient, high-throughput AI systems.

M. J. Neves

The fermion sector of the pseudo-quantum electrodynamics is integrated functionally to generate a non-linear electrodynamics, that it is called Euler-Heisenberg pseudo-electrodynamics. A non-local Chern-Simons topological term is added to the original lagrangian of the pseudo-quantum electrodynamics in which a most complete electrodynamics gauge invariant in 1+2 dimensions is proposed. As consequence of the fermionic sector, we obtain a non-linear contribution in the electromagnetic fields that breaks the Lorentz symmetry due to Fermi velocity. From the Euler-Heisenberg pseudo-electrodynamics, we study the properties of the plane wave propagating in a planar medium under an uniform and constant electromagnetic background field. The properties of the planar material are discussed through the electric permittivity tensor and magnetic permeability, that are functions of the frequency, wavelength and of the background fields. The dispersion relations and the refractive index are calculated in the presence of a uniform magnetic field, and also in the case only of an electric background field. The birefringence phenomenon emerges only when the electric background field is considered.

Rahul Nellikkath, Spyros Chatzivasileiadis

Oliwia Gołyga, Grzegorz Muziol, Anna Feduniewicz‐Żmuda et al.

Abstract The integration of photonic elements with nitride optoelectronic structures allows control of emitted light properties, which is advantageous for achieving, e.g., a single wavelength lasing. Positioning of the photonic structures on the top surface of GaN‐based devices is problematic, in particular, for deposition of a metal contact to p‐type top layer. In this work, custom‐shaped submicron air channels arranged periodically 150 nm below the sample surface, forming an air/GaN diffraction grating embedded within a volume of the structure is proposed and fabricated. The fabrication process includes selective area Si ion implantation, GaN regrowth using plasma‐assisted molecular beam epitaxy, ultra‐high‐pressure annealing for efficient electrical activation of implanted Si without diffusion, and electrochemical etching for the removal of selectively doped material. Embedded air/GaN diffraction gratings with periodicity of 460 and 631 nm are shown. Width of air channels ranges from 46 to 320 nm. Angle and polarization resolved reflectivity measurements combined with theoretical modeling confirm the designed optical performance of the embedded diffraction gratings in the GaN volume. The presented design and fabrication of custom‐shaped, fully integrated photonic structures buried below the surface paves the way for novel type constructions of optoelectronic devices, such as compact distributed feedback laser diodes

Tim Kruse, Luciana Tavares, Ulrich Schürmann et al.

A process for the construction of a high voltage aluminium polymer electrolytic capacitor with operation voltages of up to 700 V is presented in this paper. Thin 150 μm, high purity aluminium films are anodized at a constant voltage with various anodization steps in a dilute boric acid solution to voltages between 1000 V and 1500 V. Single capacitor stacks were built, using the anodized aluminium, commercial cathode foils, paper separator and a PEDOT:PSS electrolyte. The resulting capacitors were electrically characterized by their capacitance, equivalent series resistance, breakdown voltage, and leakage current. Capacitance measurements showed that the thickness of the oxide film grew linearly with the forming voltage. The breakdown voltage exhibits a saturation behaviour with rising forming voltages, meaning that thicker oxide grown at voltages higher than 1000 V does not lead to proportional higher breakdown voltages. Oxide investigations showed that many defects are present at the surface at the highest forming voltages. Cross sections showed that the oxide underneath these defects have many voids that presumably lead to an earlier breakdown. Nonetheless, at a forming voltage of 1500 V, the breakdown voltage of the capacitor cells is at an average of 789 V with some samples going up to 800 V, which is more than three times the rated voltage of state-of-the-art devices.

Yannik Junk, Omar Concepción, Marvin Frauenrath et al.

Abstract As transistors continue to shrink, the need to replace silicon with materials of higher carrier mobilities becomes imperative. Group‐IV semiconductors, and particularly GeSn alloys, stand out for their high electron and hole mobilities, making them attractive for next‐generation electronics. While Ge p‐channel devices already possess a high hole mobility, here the focus is on enhancing n‐channel transistor performance by utilizing the superior electron mobility of GeSn as channel material. Vertical gate‐all‐around nanowire (GAA NW) transistors are fabricated using epitaxial GeSn heterostructures that leverage the material growth, in situ doping, and band engineering across source/channel/drain regions. It is demonstrated that increasing Sn content in GeSn alloys constantly improves the device performances, reaching a fivefold on‐current improvement over standard Ge devices for 11 at.% Sn content. The present results underline the real potential of the GeSn alloys to bring performance and energy efficiency to future nanoelectronics applications.

In‐Kook Hwang, Min Gu Lee, Jae Bum Jeon et al.

Abstract This study presents visible‐light chiral photonic synaptic devices based on 2D chiral hybrid organic‐inorganic perovskites (HOIPs), composed of Si/SiO₂/chiral HOIPs/poly(methyl methacrylate)/pentacene/Au, designed for circularly polarized light (CPL)‐active peripheral nervous system (PNS) applications. In the heterostructure of 2D chiral HOIPs and pentacene, chiral HOIPs effectively distinguish the direction of CPL and the pentacene layer extracts photoinduced charge carriers to achieve synaptic properties, as confirmed by circular dichroism and photoluminescence analyses. The devices exhibit a photocurrent dissymmetry factor of up to 0.3 and a photoresponsivity of 130 mA W−1. Logic operations using a 3 × 4 pixel array of chiral HOIP‐based heterostructures are demonstrated, achieving pattern recognition based on the direction of CPL and pulse interval time. Notably, the efficiency to discriminate CPL direction increases with longer pulse intervals. This improvement enhances the learning capability by amplifying CPL direction discrimination ratios. Leveraging these properties, neural network simulations for neuromorphic applications are conducted, and artificial neural networks are trained for image recognition using the devices as CPL filters, achieving a 92% recognition accuracy. These results signify the beginning of chiral PNS devices communicating with visible CPL based on 2D chiral HOIPs.

Shubhang Pandey, T.G. Venkatesh

Recent advances in 3D fabrication have allowed handling the memory bottlenecks for modern data-intensive applications by bringing the computation closer to the memory, enabling Near Memory Processing (NMP). Memory Centric Networks (MCN) are advanced memory architectures that use NMP architectures, where multiple stacks of the 3D memory units are equipped with simple processing cores, allowing numerous threads to execute concurrently. The performance of the NMP is crucially dependent upon the efficient task offloading and task-to-NMP allocation. Our work presents a multi-armed bandit (MAB) based approach in formulating an efficient resource allocation strategy for MCN. Most existing literature concentrates only on one application domain and optimizing only one metric, i.e., either execution time or power. However, our solution is more generic and can be applied to diverse application domains. In our approach, we deploy Upper Confidence Bound (UCB) policy to collect rewards and eventually use it for regret optimization. We study the following metrics-instructions per cycle, execution times, NMP core cache misses, packet latencies, and power consumption. Our study covers various applications from PARSEC and SPLASH2 benchmarks suite. The evaluation shows that the system’s performance improves by ∼11% on average and an average reduction in total power consumption by ∼12%.

Xianfa Cai, Xiaowen Han, Jiaqi Xie et al.

Abstract Flexible devices derived from piezoelectric materials have gained considerable attention due to their exceptional biocompatibility. Among these, ferroelectret nanogenerators (FENG) is a novel type of flexible piezoelectric device that integrates self‐powering, actuation, and sensing capabilities. Its potential applications within the realm of human physiological medicine are continuously expanding. Given the increasing public emphasis on health, demand is escalating for devices that can monitor human activity indicators and reflect the state of bodily functions. In this context, flexible devices with superior biocompatibility have become increasingly valuable for medical testing, sports training guidance, and physical exercise. Due to its exceptional flexibility, high sensitivity, significant piezoelectric coefficient, and excellent biocompatibility, FENG has garnered considerable attention in medical applications, demonstrating strong potential for accurately detecting human physiological activities. Therefore, an in‐depth exploration of FENG's applications in medical testing and auxiliary treatment carries significant practical implications. However, current research on FENG's application in the medical field lacks comprehensive understanding and systematic evaluation. This paper aims to review the most recent advancement in the application of FENG in medical settings. By presenting a wide variety of application examples and systematic evaluations, we aim to demonstrate that FENG can meet the personalized needs of the medical application field. First, this paper introduces the working principle of FENG and its fabrication methods, followed by an introduction to FENG's applications in four major human physiological systems: blood circulation, respiration, muscle movement, and nerve reflexes. Finally, potential directions for further development of FENG and the challenges faced are discussed.

Achraf El Bouazzaoui, Omar Mouhib, Abdelkader Hadjoudja

This paper presents NeuroAdaptiveNet, an FPGA-based neural network framework that dynamically self-adjusts its architectural configurations in real time to maximize performance across diverse datasets. The core innovation is a Dynamic Classifier Selection mechanism, which harnesses the k-Nearest Centroid algorithm to identify the most competent neural network model for each incoming data sample. By adaptively selecting the most suitable model configuration, NeuroAdaptiveNet achieves significantly improved classification accuracy and optimized resource usage compared to conventional, statically configured neural networks. Experimental results on four datasets demonstrate that NeuroAdaptiveNet can reduce FPGA resource utilization by as much as 52.85%, increase classification accuracy by 4.31%, and lower power consumption by up to 24.5%. These gains illustrate the clear advantage of real-time, per-input reconfiguration over static designs. These advantages are particularly crucial for edge computing and embedded applications, where computational constraints and energy efficiency are paramount. The ability of NeuroAdaptiveNet to tailor its neural network parameters and architecture on a per-input basis paves the way for more efficient and accurate AI solutions in resource-constrained environments.

Wanxing Lin, Xiaobo Li, Yan-Ling Zhao

We propose a scheme for driving a dipolar molecular rotor to rotate continuously by applying an external electric field: the dipolar rotor is fixed on a graphene sheet via a metal atom to facilitate the free rotation; it is in the meantime subjected to an electric field oriented parallel to the graphene sheet. We use computational modeling with density functional theory and Newtonian mechanics, similar to molecular dynamics simulations, to obtain the torque, angular velocity, and rotation period of the rotor. Our results show that the dipolar rotor designed here can rotate with a period of 2.96 ps by an alternating rectangular electric field with a strength of 0.5 V/Å. However, a cosine wave alternating electric field depending on time cannot drive the dipolar rotor to rotate regularly. Therefore, a cosine wave electric field depending on the rotation angle is suggested, as it can not only drive the rotor but also produce additional power. Machine learning molecular dynamics (MLMD) simulations further confirm that the rotor remains thermodynamically stable under an electric field. This work reveals the rotation mechanism of a dipolar molecular rotor in a transverse electric field, and we hope this work can open a new path for designing more diverse molecular machines in experiments.

Mario J. Pinheiro

This work establishes a theoretical framework connecting conformal symmetry in electromagnetism to self-sustaining processes in electrical circuits. Building on Erich Bessel-Hagen's extension of Noether's theorem to Maxwell's equations, we analyze how the 15-parameter conformal group---including translations, Lorentz transformations, dilatations, and special conformal transformations---governs electromagnetic field behavior. Through a Lagrangian formulation of circuit dynamics, we map these symmetries to component-level transformations and derive conformally extended versions of Kirchhoff's laws featuring: i) Geometry-dependent weighting factors ($w_i \propto \lambda_i^{-1}$); ii) A dilaton-like field interaction term ($\Phi_\delta$). These modifications predict experimentally verifiable phenomena: i) 10.2\% deviations from classical current division in RF splitters; ii) 4.2\% resonant frequency shifts and 2.67$\times$ quality factor enhancements in RLC circuits; iii) Power-law scaling ($J_z \propto a^{-2}$) for cylindrical conductor current densities. We propose a field equation for the \textbf{dilaton-like field} $\delta$: \[ \frac{1}{r}\frac{\partial}{\partial r}\left(r\frac{\partial\delta}{\partial r}\right) + \cdots = \kappa(E^2 - B^2) \] which mediates energy exchange via the \textbf{dilaton potential} $\Phi_\delta$ in modified Kirchhoff's laws between the circuit and conformal background. This work bridges high-energy physics and electrical engineering, demonstrating how conformal symmetry can enable novel circuit behaviors---including self-sustaining oscillations in cylindrical geometries---that transcend lumped-element approximations.

Farzin Asadi

Farzin Asadi

Amir Ali Mohammad Khani, Ava Salmanpour, Ali Soldoozy et al.

Here a novel ultra-thin meta-material structure is proposed, including periodic arrays of graphene rings, disks, and ribbons and SiO2 dielectric as spacer between graphene patterns layers at the terahertz (THz) range. The introduced device can couple electromagnetic waves by considering reflection and transmission channels as outputs. Electromagnetic wave coupling depends on the parameters design and the device thickness. The proposed structure can couple electromagnetic waves in multi-band and close frequencies including 2 THz, 4 THz, 6 THz, 7.5 THz, and 9.5 THz. By considering the impedance matching concept, an equivalent circuit model (ECM) is developed for the proposed meta-material. Also, the device stability is investigated in various physical coefficients, geometrical parameters, and incident wave angles to ensure optical applications such as sensors, indoor communications, security, and medical imaging.

M. Kodama, N. Uno, Y. Takase et al.

Lithium-metal anodes are promising electrodes for fabricating high-capacity all-solid-state batteries; however, lithium dendrite growth during charging limits their applicability. One method to suppress lithium dendrite growth is to insert a carbon interlayer between the solid electrolyte and the lithium-metal anode. There are many potential approaches for inserting a carbon interlayer. The optimal conditions for suppressing lithium dendrite growth and ensuring uniform lithium deposition have not yet been established. This study employs X-ray computed tomography to investigate anode-less all-solid-state batteries. Pressurized xenon is used to examine how the carbon interlayer functions and how uniformly lithium is deposited after various carbon interlayer insertion processes. Uniform deposition is observed following simultaneous pressure bonding of the carbon interlayer and compression of the solid electrolyte.

Guilherme Cirilo Leandro, Taku Noda

Michael Putra Kusuma, Nur Rohman Rosyid

Pada tahun-tahun terakhir, Laboratorium Virtual telah semakin marak digunakan oleh organisasi di seluruh dunia sebagai media pembelajaran dan tempat melatih skill di bidang teknologi informasi dengan menyediakan virtual machine lab yang dapat dibuat dan diberhentikan menggunakan tombol yang terdapat di website pembelajaran. Dengan adanya purwarupa Laboratorium Virtual yang menerapkan Infrasructure as Code, maka hal tersebut akan memudahkan Administrator infrastruktur dalam mengelola infrastruktur virtual. Diperlukannya sebuah antarmuka berbasis website yang dapat melakukan pembuatan virtual machine lab, melihat status virtual machine lab yang dibuat serta menghapus virtual machine lab yang telah dibuat jika sudah tidak ingin menggunakan virtual machine lab tersebut. Pengembangan purwarupa website Laboratorium Virtual ini mengunakan PHP sebagai server side scripting untuk menjalankan script dari tiap fiturnya. Infratruktur as Code pada purwarupa ini berfungsi sebagai otomatisasi pengelolaan dan penyediaan virtual machine lab pada VMWare ESXi menggunakan Terraform. Sebelum dapat mengakses website tersebut, user yang terdaftar di database diharuskan untuk login terlebih dahulu sehingga dapat diarahkan ke folder yang telah disediakan untuk masing-masing user. Harapan dengan adanya aplikasi website ini adalah dapat memudahkan Administrator infrastruktur laboratorium dalam melakukan manajemen virtual machine lab, sehingga tidak perlu repot-repot lagi untuk melakukan konfigurasi tiap virtual machine secara manual bagi tiap user.

Yunjae Kim, Hyoungsoo Kim, Jongwook Jeon et al.

In this study, a floating-gate field-effect transistor (FGFET) structure is proposed and verified through simulations. Current memory devices often rely on the von Neumann architecture which suffers from von Neumann bottleneck. The proposed FGFET is not vulnerable to the von Neumann bottleneck because the memory cell and process unit do not function separately. FGFET is composed with Sensor FET(SFET) and Vertical FET(VFET), which can form a memory node with connection of each part. Moreover, the advantage of FGFET is that the conventional CMOS process can be used. In this regard, the developed FGFET using the existing CMOS process shows that the circuit size, power consumption, and operation delay are significantly reduced compared to a conventional logic circuit. Furthermore, various circuit simulations comprising the proposed FGFET, such as an inverter and NAND/NOR gate, are performed, highlighting the advantages of the proposed FGFET. This study lays the foundation for using a CMOS-based memory logic integrated device and architecture for alleviating the von Neumann bottleneck.