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

Marie Isabelle Büschges, Christian Dietz, Vanessa Trouillet et al.

ABSTRACT Zirconium and hafnium doped indium tin oxide (ITO) thin films are fabricated via atomic layer deposition (ALD) at 200°C from trimethylindium, tetrakis(dimethylamido)tin, tetrakis(dimethylamido)zirconium, and tetrakis(diethylamido)hafnium, using water as oxidant. Grazing incidence X‐ray total scattering employing synchrotron radiation reveals a highly disordered structure with a short‐range order, exhibiting correlation lengths of up to ∼13 Å. This is also reflected in high‐resolution transmission electron microscopy, revealing an amorphous intermixed state of all constituting components. Increasing amounts of fully coordinated oxygen species with increasing amounts of dopant are evidenced by X‐ray photoelectron spectroscopy analysis and attributed to zirconium and hafnium's ability to form strong oxygen bonds, and thereby suppressing the formation of oxygen vacancies. The Zr‐ and Hf‐doped ITO thin films are integrated into thin‐film transistor (TFT) devices to evaluate their suitability as semiconducting material. The electrical measurements reveal saturation mobilities (µsat) of 1.92–9.81 cm2 V−1 s−1, with high current on/off ratios (IOn/IOff) of 106–108. This study demonstrates the subtle influence of small amounts of Zr and Hf on TFT performance. This proves the ability to control the electrical behavior of TFT devices by controlled incorporation of dopants like Zr and Hf into their active channel layer.

Yujie Du, Yongliang Zheng, Hong Liu et al.

Abstract Water and energy are the cornerstones of human development, with more than half of the world's population facing water scarcity issues. Atmospheric moisture is widely distributed around the globe, and the rational utilization of moisture can create tremendous value. Here, the sources of hygroscopic materials, methods of manufacturing hydrogels, properties of these hydrogels, and potential energy applications are concluded. To make the hydrogels with high hydrophilicity, ultrasonic oscillation, freeze drying, and spin coating can be used as the synthesis strategies. The main focus is on the characteristic parameters of hydrogels with water uptake, dehydration temperature, conductivity, mechanical stability, swelling behaviors, and heat transfer coefficient. These unique features will affect the performances of assembles, devices, and instruments. Subsequently, the potential applications of hydrogels are summarized, such as moisture harvesting and splitting with fuel production, dehumidification, thermal management in electronic devices, solar water evaporation, and electricity production. Finally, future directions and issues of interest are proposed to promote the diverse development of hydrogels and relational systems.

Jack Guida, Chuan Tian, Kenneth E. Kolodziej et al.

Simultaneous transmit and receive, or in-band full-duplex (IBFD), holds significant promise for radar and wireless communication systems using time-domain cancellation at radio frequencies. These systems rely on precise control of group delay to effectively mitigate self-interference. Piezoelectric-based traveling microwave acoustic wave devices provide a compact, passive means to implement such delays with high fidelity. This work explores the integration of piezoelectric acoustic delay lines to enhance self-interference cancellation (SIC) performance through precise group delay control and demonstrates SIC with such devices for a single tap demonstration.

David C. Garrett, Yousuf Aborahama, Jinhua Xu et al.

Microwave ablation is an established minimally invasive technique that induces thermal necrosis in centimeter-scale tumors in organs such as the liver and kidney. However, the efficacy of clinical protocols is challenged by patient-specific and tissue-specific variations that may require personalized parameters to achieve optimal therapeutic outcomes. To address these limitations, we introduce an imaging technique employing modulated microwave signals that maintain peak and average powers comparable to those of existing clinical systems (∼100–200 W). This modulation introduces time-varying tissue heating, generating detectable thermoacoustic signals that are used to reconstruct images proportional to the spatial heat deposition. When combined with thermal models of the tissue, we estimate the spatial temperature profile and ablation status over time. We validate this approach in ex vivo bovine liver compared against ultrasound tomography and tissue dissection. This approach may enable closed-loop monitoring and adaptive control of ablation procedures to optimize lesion coverage while sparing surrounding healthy tissue.

Farzin Asadi

Md. Tarekuzzaman, Khandoker Isfaque Ferdous Utsho

Abstract Perovskite solar cells (PSCs) are emerging as promising candidates for next‐generation photovoltaics due to their remarkable optoelectronic properties. In this study, SCAPS‐1D(Solar cell Capacitance Simulator) simulations are employed to evaluate the photovoltaic performance of a lead‐free double perovskite, Cs2TlAsI6, as an absorber material. A total of 54 device architectures are systematically explored by combining six different electron transport layers (ETLs: Ws2, TiO2, C60, PCBM, IGTO, and LBSO) with nine‐hole transport layers (HTLs: CBTS, Cu2O, CuI, CuSCN, P3HT, PEDOT: PSS, PTAA, GaAs, and CdTe), using Ni as the back contact. The ITO/Ws2/Cs2TlAsI6/Cu2O/Ni configuration achieves the highest power conversion efficiency (PCE) of 26.92%. Further optimization examines the influence of absorber thickness, ETL hthickness, and defect densities on performance. Detailed analyses include band alignment (VBO/CBO), interface defects, carrier dynamics, quantum efficiency, capacitance profiles, Mott–Schottky behavior, and impedance spectra. Additionally, the effects of series and shunt resistance, temperature, and back contact selection are investigated. Structural stability of Cs2TlAsI6 is confirmed via tolerance factor analysis, including Goldschmidt's and a newly proposed parameter. This simulation‐driven architectural optimization offers new insights into the potential of Cs2TlAsI6‐based PSCs and provides practical design strategies for high‐efficiency, lead‐free photovoltaic devices.

Patrick Diehle, Stephan Gierth, Mickael Lejoyeux et al.

The measurement of doping concentrations is a fundamental need for the development and processing of power electronic devices like normally-off semi-vertical GaN trench MOSFETs. We employed highly laterally resolved TOF-SIMS to evaluate the doping levels of the n- and p- doped layers close to the gate trench. A lateral resolution of approx. 100 nm was achieved sufficient to resolve the gate trench geometry. Furthermore, the analysis and the visualization of the 3D data was optimized by implementing the correction of the topography and image distortions. No change of the Mg and Si doping of the n- and p- layers close to gate trench sidewall was observed.

Wenbo Liu, Jiaheng Zheng, Guangdong Shi et al.

This study aims to explore the application of deep learning techniques, particularly optimized long short-term memory networks (LSTM), in the diagnosis of hydraulic system faults and parameter recognition in intelligent sensing agriculture. Firstly, the hydraulic system was modeled and the key parameters and state variables in the model were identified. Next, the LSTM network is introduced to optimize the model through its unique internal structure. LSTM can effectively capture long-term dependencies in time series data, making it an ideal choice for handling hydraulic systems involving dynamic behavior. To evaluate the performance of the model, 2000 data points were collected and preprocessed, of which 1897 data points were used for experiments. Based on these data, model performance was tested under different operating conditions. The research results show that the optimized LSTM model performs well in parameter recognition and fault diagnosis, especially under standard operating conditions, with a relative error rate of only 1.5 %. Considering different operating conditions and fault modes, the proposed model demonstrates good robustness and practicality in hydraulic system fault diagnosis, especially with an accuracy of over 90 % in leakage fault diagnosis, and remains stable under various operating conditions. This study provides strong support for the application of deep learning technology in hydraulic system fault diagnosis, and valuable insights for the performance optimization and application expansion of future models.

K. Bakke

We introduce a nonminimal coupling into the Dirac equation as a model of describing the interaction of a Dirac neutral particle with an induced electric dipole moment with magnetic and electric fields. Then, we obtain a relativistic geometric quantum phase from the interaction of the induced electric dipole moment with electric and magnetic fields. Further, we include the permanent magnetic dipole moment of the Dirac neutral particle besides the induced electric dipole moment and obtain the relativistic geometric quantum phase.

Saad Jbabdi

Sergejs Afanasjevs, Helen Benjamin, Konstantin Kamenev et al.

Abstract The piezoelectronic transistor (PET) has been proposed to overcome the voltage and clock speed limitations of conventional field‐effect transistors (FET). In a PET, voltage is transduced to stress, which leads to an insulator‐metal transition in a piezo‐resistive (PR) element. Although the simulated switching speeds are promising, the viable candidates proposed so far for the PR layer are rare earth compounds that require several GPa of pressure (P) to metalize, necessitating breakthroughs in transduction mechanism scaling and processing. Here, a PR candidate that metalizes in the 0–300 MPa range – the transition metal complex platinum benzoquinonedioximato (Pt(bqd)2) is demonstrated. Such electrical sensitivity to the application of P arises when the material is grown as a thin film with the preferred needle orientation perpendicular to the substrate. As evidence, a combination of hydrostatic and uniaxial pressure studies is provided. The former studies are produced on the compressed powder pellet in a specially developed piston‐cylinder cell (P‐C cell) under variable temperatures (T) and P. The latter is via thin film deposition and uniaxial resistivity (ρ) measurements and these revealed the high potential of this material for the PET concept.

Yasser REHAIL , Youcef ZENNIR , Noureddine TCHOUAR

Chemical accidents always result in significant losses due to the flammable, explosive, and toxic characteristics of hazardous chemicals. Analysis of process safety parameters is an effective way to prevent hazardous chemical accidents and reduce losses. System-theoretic process analysis (STPA) is a newer hazard analysis technique that is based on systems theory. It has been shown to be effective in identifying hazards in other industries, but its application in oil and gas plants is still rare and limited due to systems complexities and other challenges. This paper aims to apply the STPA method to a complex system “column C-63” at the Skikda RA1K refinery to prevent the explosion scenario of naphtha. The results show that STPA was able to identify the root causes of the explosion scenario, which is important for preventing chemical risks.

Renan Colucci, Bianca de Andrade Feitosa, Gregório Couto Faria

Abstract The organic electrochemical transistor (OECT) has received considerable interest in the field of bioelectronics due to its ability to support both ionic and electronic transport. However, the fundamental aspects of the OECT's operation are not yet fully understood. Here, the impact on the performance of poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)‐based OECTs, of a series electrolytes with chloride‐based ions is evaluated, varying their cation counterpart under the extension of the Hofmeister Series. Electrical results are analyzed using the Bernards‐Malliaras and Faria‐Duong models and correlated with quartz crystal microbalance measurements. It is shown that cations with a higher ability of salting‐in, according to the Hofmeister series, swell the channel with higher efficiency. In addition, cations with a higher ability to salt‐out promote smaller modulations in the channel's current, indicating that the ionic transport in the bulk of the channel is directly correlated with the swelling ability of the film. Overall, the results provide a better understanding of the interplay of channel and electrolyte in OECTs and promote guidelines for optimizing materials choice for highly sensitive OECTs.

Pedro Fernandes Paes Pinto Rocha, Mohammed Zeghouane, Sarah Boubenia et al.

Abstract Electrical and material properties of plasma‐enhanced atomic layer deposited (PE‐ALD) AlON on dry‐etched n‐type GaN substrates are investigated for nitrogen concentration ranging from 1.5% to 7.1%. Firstly, an increase in flat‐band voltage (VFB) and its hysteresis with increasing nitrogen concentration is reported. The increase in VFB is associated with the nitrogen content whereas the increase in hysteresis to the presence of impurities (hydroxyl groups and carbon‐related impurities). Alongside the nitrogen concentration, the impact of different post‐deposition annealing (PDA) temperatures is studied (400–800 °C). Stable AlON layers and interfaces with etched GaN substrates are reported with slight gallium oxide growth or gallium diffusion towards the dielectric layer. Finally, with increasing PDA temperature, an increase in VFB and a significant reduction of both VFB hysteresis and interface state density (Dit) are observed, notably at the measuring temperature of 150 °C. These results present a promising pathway toward more reliable and stable normally‐OFF GaN‐based MOS‐channel high electron mobility transistors (MOSc‐HEMTs).

M. Caramello, M. Frignani, R. Beaumont et al.

Abstract There has recently been growing interest in the development of innovative nuclear technologies that offer greater sustainability and cost effectiveness of electricity production. One of the most promising options is the lead fast reactor (LFR) technology. Lead stands out for its favorable neutron properties, allowing a hard neutron spectrum core as well as good shielding, heat transfer, and radioisotope retention capabilities. As lead has a boiling point in excess of 1700°C and does not react exothermically with either air or water, it also allows for the design of a low-pressure reactor block without an intermediate cooling circuit, which is used in other advanced reactor technologies for protecting against the interaction between primary and power conversion system coolants. The deployment of a new fleet of fast reactors is conditional on the control/prevention of the corrosion and erosion effects of the coolant against the structural materials, the systematic characterization of the interaction phenomena between the coolant and fuel and water, and the experimental qualification of innovative systems and components. To support LFR technology development, the UK Department for Business, Energy & Industrial Strategy has recently allocated 10 M£ to a team composed of Westinghouse Electric Company LLC, the Ansaldo Nuclear Group, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, the University of Manchester, and other organizations for the design, construction, and first operation of a network of eight test infrastructures widespread in the United Kingdom to address the LFR’s highest priority research and development needs. One of the experimental rigs is the Versatile Loop Facility (VLF) currently under construction at the Ansaldo Nuclear Group’s workshop in Wolverhampton, United Kingdom. The plant consists of a lead loop operable up to 650°C and equipped with a 500-kW electric fuel bundle simulator (resembling the Westinghouse LFR bundle) and a hybrid microchannel-type diffusion-bonded heat exchanger (which simulates the primary heat exchanger adopted in the Westinghouse LFR design). The heat removal is delegated to a supercritical water-cooling loop having a design pressure of 330 bar and maximum operating temperatures up to 620°C. In this paper we present the design of the VLF with specific details about its prototypical components and an insight into the construction and installation phases currently underway.

Rabia Tahir, M. Waqas Hakim, Adil Murtaza et al.

Abstract In recent years, multiferroic (MF) materials have attained remarkable attention because of their exceptional ability to demonstrate both ferroelectric (FE) and magnetic properties simultaneously which has lead to their applications in memory, sensors, and energy storage devices. Here, a simple synthesis approach is used to enhance the ferroelectricity and induce the multiferroicity in double transition metal carbide (DTM) MXene film. The successful synthesis is confirmed by X‐ray Diffraction (XRD), Raman Spectroscopy, and Scanning Electron Microscopy (SEM) analysis. In addition, the FE and magnetic hysteresis (MH) loops are conducted to observe the nature of synthesized materials. Furthermore, the magnetoelectric (ME) effect is also examined to explore its significance in data storage and ME signal generation devices. Thus, the findings reveal the first report on the co‐existence of FE and magnetic properties of DTM MXene for potential applications in nano‐electronic devices of future technology.

Megan C. Robinson, Jack A. Molles, Vadim V. Yakovlev et al.

Microwave heating of waste results in chemical breakdown that can lead to conversion of mixed waste materials to fuel. Heating waste mixtures with microwave energy rather than incineration results in faster breakdown and can therefore be more efficient. Here we address heating of small volumes of mixed food waste materials with widely differing and temperature-dependent electrical properties. Uniform heating is accomplished with mode mixing within a loaded cavity and by spatial power combining of solid-state power amplifiers (SSPAs). We present a heating comparison of two circuit-combined and spatially-combined 2.45 GHz 70-W 65% efficient GaN SSPAs with controlled relative phase. The heating efficacy is shown to improve by volumetric combining inside the waste loading. The temperature changes in several locations and for several common waste materials and mixtures are investigated and compared to FEM electromagnetic simulations, as well as FDTD multi-physics simulations that incorporate thermal dependence of material properties. The approach is scalable in volume and power, demonstrated by a simulation comparison of the 1.4 L small cavity to a 5.2 L volume.

Jimin Han, Kitae Park, Hyun‐Mi Kim et al.

Abstract Tunable multilevel gate oxide capacitance and flat‐band voltage shift characteristics in double‐floating‐gate metal–oxide–semiconductor (DFG‐MOS) capacitors are investigated for non‐volatile memory and programmable logic device applications. The DFG‐MOS capacitor with the structure of Ag(control gate)/CeO2(upper control oxide)/Al(upper FG)/CeO2(lower control oxide)/Pt(lower FG)/HfO2(tunneling oxide) on n‐Si substrate, that is Ag/CeO2/Al/CeO2/Pt/HfO2/n‐Si, exhibits three capacitance states as a result of reversible formation and rupture of conducting filaments at serially stacked Ag/CeO2/Al and Al/CeO2/Pt capacitors upon applying positive and negative gate voltages, respectively. In contrast, the DFG‐MOS capacitor with Ag/CeO2/Pt/HfO2/Pt/HfO2/n‐Si employing inert Pt upper and lower FGs exhibits two capacitance states via the formation and rupture of filament only at the upper Ag/CeO2/Pt stack. Instead, it accompanies a flat‐band voltage shift by electrical charging at the lower FG of Pt. The proposed devices operate with tunable multilevel gate oxide capacitance and flat‐band voltage shift associated with filament formation inside gate stacks and electrical charging with respect to the constituent materials of the FGs. These results pave the way for potential application to non‐volatile memory and programmable MOSFET logic device with tunable gate oxide capacitance, without relying solely on the electrical charging used in the current flash‐type memory.

Giovanni Ghione, Marco Pirola

In the design of amplifier stages based on unconditionally stable linear active two-ports, the amplifier gain can be maximized through simultaneous conjugate matching with passive loads at the input and output ports. Conversely, the optimization of linear amplifiers based on conditionally stable active devices requires a trade-off between gain, stability margin, input/output port mismatch and (for low-noise amplifiers) noise figure. Exploiting potentially in-band unstable devices can be advantageous in the design of open-loop low-noise amplifiers, since the in-band stabilization with input resistors is well known to negatively affect the amplifier minimum noise figure. Within this framework, the article derives a lower bound to the input and output mismatch of non unconditionally stable linear two-ports. The minumum mismatch is shown to only depend, in a simple way, on the stability factor <inline-formula><tex-math notation="LaTeX">$K$</tex-math></inline-formula> and on the assumed mismatch ratio between the two ports. The minimum mismatch condition can be implemented by cascading the active, potentially in-band unstable two-port with two (input and output) reactive matching sections. The application of the theory to the design of low-noise amplifier open-loop stages based on conditionally stable active devices is discussed through CAD examples.