Electrical Modulation Research Articles

Enhanced photocatalytic hydrogen production through modification of B←N coordination units

Built-in electric field construction and energy band modulation of B←N containing polymer units to expand B←N photocatalyst systems.

Noncontact Time-Varying Current Reconstruction for Electromagnetic Immunity Diagnosis in Electric Vehicle Module Injection Port Testing

Noncontact Time-Varying Current Reconstruction for Electromagnetic Immunity Diagnosis in Electric Vehicle Module Injection Port Testing

Conductive gradient hydrogels allow spatial control of adult stem cell fate.

Electrical gradients are fundamental to physiological processes including cell migration, tissue formation, organ development, and response to injury and regeneration. Current electrical modulation of cells is primarily studied under a uniform electrical field. Here we demonstrate the fabrication of conductive gradient hydrogels (CGGs) that display mechanical properties and varying local electrical gradients mimicking physiological conditions. The electrically-stimulated CGGs enhanced human mesenchymal stem cell (hMSC) viability and attachment. Cells on CGGs under electrical stimulation showed a high expression of neural progenitor markers such as Nestin, GFAP, and Sox2. More importantly, CGGs showed cell differentiation toward oligodendrocyte lineage (Oligo2) in the center of the scaffold where the electric field was uniform with a greater intensity, while cells preferred neuronal lineage (NeuN) on the edge of the scaffold on a varying electric field at lower magnitude. Our data suggest that CGGs can serve as a useful platform to study the effects of electrical gradients on stem cells and potentially provide insights on developing new neural engineering applications.

Relationships of Abstraction and Application Complexity in the Attainment between Mathematics and Electrical Engineering Modules in Diploma Courses of South Africa

In South Africa, universities are under pressure to meet increasing targets for student enrolment in engineering disciplines and fields. This has resulted in many students being enrolled in engineering programs without possessing the minimum required mathematical skills and understanding to tackle the challenging engineering disciplines. Hence, the engineering disciplines have a high student attrition and failure rate. This study aimed to evaluate the complex relationship of abstraction and application between mathematics attainment and principles of electrical engineering attainment by the students enrolled in diploma courses in technical universities of South Africa. A blend of quantitative and qualitative data was used. Legitimation code theory (LCT) was used to determine the complexity of higher learning levels. The relationships between six core courses in the Electrical Engineering curriculum were investigated to analyze the knowledge building from mathematics modules to principles of electrical engineering modules. The problem-solving, analytics, and abstract mathematical skills developed in these modules impact the overall progression into principles of electrical engineering courses at different levels for diverse students. The research examines the theoretical foundation, student performance, and practical application of mathematical ideas in electrical engineering using curriculum documents, student academic records, and interviews with electrical engineering lecturers. The study found a weak correlation between the two modules and examined how resources, cultural attitudes, and pedagogy affect student achievement. The results indicate an unexpected negative and fragile correlation between the lower mathematics and engineering modules at high levels. The LCT analysis showed the disconnect between the mathematics courses and the principles of electrical engineering in both the level of abstraction used in the studies and the extent of application principles taught.

Synergistic engineering of P, N-codoped carbon-confined bimetallic cobalt/nickel phosphides with tailored electronic structures for boosting urea electro-oxidation

Bimetallic phosphides exhibit superior electrocatalytic activities and synergistic effects that make them ideal electrocatalysts for the urea oxidation reaction (UOR). Herein, P, N-codoped carbon-encapsulated cobalt/nickel phosphides derived from NiCo-MOF-74 (NiCoP@PNC) and anchored on P-doped carbonized wood fiber (PCWF) for UOR were prepared through synchronous carbonization and phosphorization. By benefiting from the synergistic effect of structural and electronic modulation, NiCoP@PNC/PCWF exhibits excellent UOR electrocatalytic performance under alkaline conditions, achieving a current density of 50 mA cm−2 with a potential of only 1.34 V (vs reversible hydrogen electrode, RHE) and continuous operation for more than 72 h. In addition, for the overall urea splitting, an electrolyzer using UOR replaced OER, which required only 1.50 V to achieve a current density of 50 mA cm−2 with excellent stability, 230 mV less than that required for the HER||OER system. In-depth theoretical analysis further proves that the strong synergistic effect between Co and Ni optimizes electronic structures, yielding excellent UOR properties. The synergistic strategy of structural and electrical modulation provides broad prospects for the design and synthesis of excellent UOR electrocatalysts for energy-saving hydrogen production by using renewable resources.

3D Printed Implantable Hydrogel Bioelectronics for Electrophysiological Monitoring and Electrical Modulation

AbstractElectronic devices based on conducting polymer hydrogels have emerged as one of the most promising implantable bioelectronics for electrophysiological monitoring and diagnosis of a wide spectrum of diseases, in light of their distinct conductivity and biocompatibility. However, most conducting polymer hydrogels‐based bioelectronics are routinely fabricated through conventional techniques, which are challenged by its intrinsic poor processability of conducting polymers, as well as the essentially fragile biointerface, thus hampering their rapid innovation and application in advanced implantable bioelectronics. Here, 3D printable hydrogels based on poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is reported, featuring superior 3D printability for direct ink writing (DIW), tissue‐like mechanical compliance (Young's modulus of 650 kPa), instant and tough bioadhesion (interfacial toughness of 200 J m−2 and shear strength of 120 kPa), highly‐tunable electrical properties, as well as long‐term in vitro and in vivo structural and electrochemical robustness. Electro‐physiological studies rat heart models with normal or arrhythmic conditions highlight the capabilities of establishing conformal biointerface with the dynamic organs, allowing for long‐term and high‐precision spatiotemporary epicardial electrophysiological monitoring, as well as electrical modulation of acute myocardial infarction (MI) model. These advances provide a promising strategy to improve the tissue‐electronics interfacing, and could serve as the basis for the next generation bioelectronics toward healthcare monitoring, diagnosis and medical therapies.

Dark Current Mechanisms and Suppression Strategies for Infrared Photodetectors Based on Two‐Dimensional Materials

AbstractNarrow‐bandgap 2D materials and semimetals, for example, graphene, black phosphorus (BP), tellurium (Te), and some novel transition metal dichalcogenides (TMDs), have been demonstrated to be promising building blocks for constructing next‐generation state‐of‐the‐art infrared (IR) photodetectors. However, these devices suffer from a significant dark current, primarily attributed to the intrinsic thermal excitation‐induced high carrier concentration. Suppressing the dark current is an essential issue in pursuing higher specific detectivity of IR photodetectors. Here, the authors demonstrate recent advances in suppressing dark current for 2D IR photodetectors. First, a brief insight into the dark current composition and mechanisms of 2D IR photodetectors is illustrated. Then, the varied band alignment for blocking dark current by the interfacial barrier is discussed. Next, localized electric field modulation by applying a gate voltage and ferroelectric materials is discussed. This method can effectively tune the concentration and distribution of carriers in the device conductive channel. Following that, interfacial engineering is summarized, by which interfacial defects can be passivated and interlayer defect‐induced dark current can be suppressed. Finally, the challenges and an outlook are delivered for developing state‐of‐the‐art IR photodetectors.

COHERENT AMPLITUDE MODULATION IN A LASER GAS SENSOR

The article is devoted to a current topic in science and technology -determining the type and concentration of gas using a laser. At close values of green laser radiation intensity and bias voltage, interference patterns of the time series of the photodiode output signal were obtained. The degree of coherence (more than ~0.1) made it possible to distinguish between the types of gases and their concentrations. Signal coherence was controlled by Allan deviation values.The novelty of the research method is the choice of the harmonic of the electrical network asthe main modulation frequency. It is shown that the correlation functions and the corresponding power spectra are sensitive to low-frequency fluctuations of molecules and their clumps. This allows the results and methods of this work to be used in specific cases instead of large-sized and expensive complexes of optical instruments at room pressure and temperature.

Development of Electro-Thermal Model for Air Cooling Study of Electric Vehicle Lithium-Ion Battery Module Operating in Indian Conditions and Drive Cycle

Lithium-ion cells have higher energy density at a specific power, making them a primary choice for battery packs in energy storage of modern technology, powering from smartphones to Electric vehicle (EV) and grid-scale energy storage systems. However, their performance, safety and lifespan are temperature sensitive and developing a fail-safe mechanism is considered as a pressing priority. In the present study, a 2D electro-thermal model is developed in MATLAB to characterize the thermal behaviour of cylindrical cells (individual and inline) during discharge. The thermal model solves the transient heat conduction equation with internal heat generation. The model is validated with the available experimental data for a single cell at a constant discharge rate and found to be in good agreement within 0.5°C. The analysis is extended to a battery module with 6 cell-inline configuration and validated. This validated model is used to study the impact of multiple cells (1-10) in inline configuration. For Indian drive cycle analysis, the current profile is estimated based on the drive cycle and its impacts on cell temperature rise in battery module is studied when subjected to variation in monthly average ambient temperature. Battery module maximum temperature rises to 60 °C and Δ T (Tmax - Tmin) across cells is 8.8 °C during summer conditions under natural convection due to multiple drive cycle loading. The battery module temperature can be kept under safe operating limits (Tmax≤ 45 °C, Δ T ≤ 4 °C) with forced convection of 2 m/s and 25 °C. The study aims to provide insights into the thermal behaviour of Lithium-ion cells that can be used to design safe and cost-effective air-cooled thermal management system for battery module.

Initial Design Studies: Identify Customer Needs and Establish Targets Specifications of the Electric Motorcycle Conversion Kit Module Product

The urgency of this research is that Indonesian people still have low interest in using electric motorbikes, indicating that sales of electric motorbikes in Indonesia are still low. Indonesian people are skeptical about electric motorbikes due to their battery life and the relatively higher price than conventional motorbikes. In this research, an additional EM module product was designed as a solution to answer these doubts. This research is an initial design process aimed at obtaining target product specifications for additional EM modules from the results of identifying user needs as a basis for the subsequent design process. The additional EM module product applies an EM conversion system that is installed on the ICEM product without losing its original ability to use a gasoline energy source, thereby minimizing procurement costs using electric motor technology on conventional motorbikes and without worrying about running out of battery when in use. This research uses the front-end activity design method to design additional EM module products and produces 30 customer needs with percentage levels of importance and 24 product specification target metrics in marginal and ideal values to be used as abasis for the subsequent design process.

Rancang Bangun Pengembangan Sistem Pompa Galon Air Otomatis Dengan Sensor Infrared Untuk Efisiensi Penggunaan Air Minum

This study examines the automation of electric gallon pumps for drinking water. This automation involves replacing the manual button on the gallon pump with a sensor, which turns on the pump and dispenses drinking water when the glass gets closer without pressing the button. This tool can also be used for gallons of drinking water ranging in size from 5 liters, 10 liters, to 15 liters. The system is designed for practical applications, and all its components are tested to understand their respective functions so as to understand the type of module that suits their needs. Test results reveal that the system is functioning as intended. Electric pump modules, infrared proximity sensors, and relay modules are some of its components.

Progress on Electro-Enhancement of Cell Manufacturing.

With the long persistence of complex, chronic diseases in society, there is increasing motivation to develop cells as living medicine to treat diseases ranging from cancer to wounds. While cell therapies can significantly impact healthcare, the shortage of starter cells meant that considerable raw materials must be channeled solely for cell expansion, leading to expensive products with long manufacturing time which can prevent accessibility by patients who either cannot afford the treatment or have highly aggressive diseases and cannot wait that long. Over the last three decades, there has been increasing knowledge on the effects of electrical modulation on proliferation, but to the best of the knowledge, none of these studies went beyond how electro-control of cell proliferation may be extended to enhance industrial scale cell manufacturing. Here, this review is started by discussing the importance of maximizing cell yield during manufacturing before comparing strategies spanning biomolecular/chemical/physical to modulate cell proliferation. Next, the authors describe how factors governing invasive and non-invasive electrical stimulation (ES) including capacitive coupling electric field may be modified to boost cell manufacturing. This review concludes by describing what needs to be urgently performed to bridge the gap between academic investigation of ES to industrial applications.

Optimization of a Reverse-Brayton cycle with inter-cooling and regeneration

A Reverse-Brayton cycle represented by the B787 electrical driven environmental control system is used as the analysis object, including the thermodynamic process of two-stage compression, intercooling, and regeneration. An analytical expression for the thermodynamic performance of the cycle is derived based on the endoreversible thermodynamic analysis model (ETM). Combined with a genetic algorithm, an ETM-based optimization approach (ETM-OA) is proposed. Using this method, it is found that the coefficient of performance is increased by 34.1 % and 48.4 % under two typical flight conditions, respectively, and the corresponding system entropy generation number is reduced by 30.2 % and 51.1 %, respectively. Both ETM-OA and entropy generation analysis show that the electric supercharging module, secondary heat exchanger, and air cycle machine are key components of the system. This study provides a convenient method for obtaining the thermal power conversion mechanism of complex thermal cycles and conducting optimization analysis.

The electronic and optical properties of Type-Ⅱ g-CN/GaGePS van der Waals heterostructure modulated via biaxial strain and external electric field

Based on the superior properties of g-CN and GaGePS monolayers, this paper investigates the optoelectronic properties of the g-CN/GaGePS van der Waals heterostructure under strain and external electric field modulation using density functional theory. The results show that g-CN/GaGePS heterostructure has a type II band alignment and possesses an indirect band gap of 0.986eV, which exhibits enhanced absorption in the visible and ultraviolet range. Under the application of a biaxial strain of 7 %, the g-CN/GaGePS heterostructure undergoes a transition from type II to type I. Furthermore, the electric field not only modulates the g-CN/GaGePS band gap, but also induces band alignment (type II to type Ⅰ) and an indirect gap to direct gap transition. The absorption in the visible range is enhanced by a positive electric field, whereas a negative electric field exerts the opposite effect. A negative electric field enhances UV range absorption. These results suggest that the g-CN/GaGePS heterostructure has prospective applications in optoelectronic devices.

Passive cooling of photovoltaic panels with latent heat storage unit: Analyzing the effects of using fins and iron nanoparticles on the performance, economy and environmental impact

This study investigates the effect of using a latent heat storage unit (LHSU) equipped with fins and nanoparticles (NAPs) on the performance of a photovoltaic (PV) system. Various PV systems were assessed for their economic viability and environmental impact. Initially, three different PV systems were designed and analyzed: a conventional PV, a PV with a paraffin-containing LHSU, and a PV with LHSU integrating 3 fins and paraffin. Results from the first set of experiments indicated that the fin-integrated system delivered the best performance. In the second phase, the most effective system from the initial stage (PV with 3 fins-added LHSU) was compared to systems with 6 fins-integrated LHSU and LHSUs integrating 6 fins and iron (Fe) NAPs. The stage specifically examined the effects of doubling the number of fins and adding NAPs to the paraffin on performance. It was found that increasing the number of fins resulted in a levelized cost of electricity (LCOE) of 0.69 USD/kWh. The electrical (module) efficiency of the system incorporating 6 fins and NAPs improved by 15.51 % compared to the conventional system. Moreover, the surface temperature of the PV panel was reduced by 7.28–17.93 % using these modifications. Performance ratio values for the five different analyzed PV systems ranged between 0.597 and 0.689. From an environmental perspective, integrating aluminum into PV systems lead to a total environmental impact of 4.73 Pt/h and an environmental impact of electricity produced (EIE) of 0.90 mPts/kWh. However, introduction of NAPs significantly increased these values to 17.76 Pt/h and 3.09 mPts/kWh, respectively. This study highlights the potential of the proposed passive cooling technique for enhancing PV system efficiency while also pointing out the necessity for design improvements to optimize economic and environmental impacts.

A multidirectional pendulum kinetic energy harvester system for low-power appliances in new energy buses

Wireless sensors play a crucial role in vehicle operations. The effective energy harvesting for self-powering these sensors has emerged as a critical area of interest in recent years. This paper presents a multidirectional pendulum kinetic energy harvester system (MP-KEHS) designed to power low-power sensors in vehicles. The MP-KEHS consists of four main components: an energy capture module, a motion transfer module, an energy conversion module, and an electric energy storage module. The energy capture module, comprising a mass ball and a turntable, captures omnidirectional inertial kinetic energy during vehicle acceleration, deceleration, and turning. In the motion transfer module, a one-way gear module converts the multidirectional rotations of the energy capture module into unidirectional rotations, while the planetary gear train enables speed coupling during simultaneous vehicle acceleration and turning. The energy conversion module utilizes a generator to transform rotational kinetic energy into electric energy. The electric energy storage module stores the electric energy in a supercapacitor after passing through a voltage regulator circuit, providing power to low-power devices. Using of multi-body dynamics software and Simulink, the swing angle of the mass ball was determined under four real driving cycles. Experimental results demonstrated that the average output power of the MP-KEHS reached 116.8 mW. Charging the capacitors of 220 μF, 470 μF, and 1000 μF from 0 V to 1 V takes 8 s, 24 s, and 93 s, respectively. Finally, the MP-KEHS was applied to a bus on the Liaocheng University campus, achieving an average output power of approximately 176 mW, which satisfied the power requirements of the sensors. These findings indicate that the MP-KEHS effectively harnesses the vehicle's otherwise wasted inertial energy, enabling wireless sensor self-powering.

Study on Electrically Modulated Quasi-Continuous Wave Fe: ZnSe Solid-State Laser with Hundred-Hertz.

Iron-doped binary chalcogenide crystals are very promising for tunable solid-state lasers operating over the 3~5 μm spectral range. Fe: ZnSe is one of the most important gain crystals with the obvious advantages of material characteristics and conversion efficiency. By adjusting the output mode of the pump source, an Fe: ZnSe laser can operate in two modes at liquid nitrogen temperatures: continuous wave (CW) and pulse output. In terms of CW output, the Fe: ZnSe laser obtained a maximum 2.63 W continuous power output which was confined to the power of the pump source. An optical-to-optical efficiency of 47.05% was acquired. Direct electrical modulation was applied to the pump source. The highest average power of the quasi-CW laser, whose central wavelength is 4.02 μm, has a value of 253 mW with an optical-to-optical efficiency of 42.88% and a full width at half maximum (FWHM) of 23 nm when the pulse frequency is 100 Hz of 10% duty factor. The output waveform is consistent with the modulation waveform applied to the pump source. We report to the first of our knowledge an electrically modulated quasi-CW Fe: ZnSe laser in the pulse regime, equipped with features of compactness in structure, ignoring additional modulators, convenience in control, high efficiency, and sustainable operation, of great interest for solving numerous scientific and applied problems.

Electrical detection and modulation of magnetism in a Dy-based ferroelectric single-molecule magnet

Electrical control of magnetism in single-molecule magnets with peculiar quantum magnetic behaviours has promise for applications in molecular electronics and quantum computing. Nevertheless, such kind of magnetoelectric effects have not been achieved in such materials. Herein, we report the successful realization of significant magnetoelectric effects by introducing ferroelectricity into a dysprosium-based single-molecule magnet through spatial cooperation between flexible organic ligands and halide ions. The stair-shaped magnetization hysteresis loop, alternating current susceptibility, and magnetic relaxation can be directly modulated by applying a moderate electric field. Conversely, the electric polarization can be modulated by applying a small magnetic field. In addition, a resonant magnetodielectric effect is clearly observed, which enables detection of quantum tunnelling of magnetization by a simple electrical measurement. The integration of ferroelectricity into single-molecule magnets not only broadens the family of single-molecule magnets but also makes electrical detection and modulation of the quantum tunnelling of magnetization a reality.

Study on the electron emission characteristics of a thermal emission cathode with grid for micro-electric thruster

The Thermal Emission Cathode with Grid (TECG) is a type of cathode that operates without a working medium based on electric field modulation, which can be effectively adapted with micro-electric thrusters to perform high-precision space science missions. This research first analyzes the thermal electron emission theory, and the key dimensional and electrical parameters of the TECG, such as the grid width, the grid-emitter distance, the grid orifice diameter, the grid voltage, and the anode voltage, are simulated using the electromagnetic simulation software OPERA to obtain the optimal combination. Subsequently, the TECG was designed and machined using the parameters above for experimental testing and verification against the simulation results. The relative error between the experimental and simulation results was less than 20%. Under specific working conditions, the TECG’s total emission capability can be increased by approximately 8 times, and the maximum emission current can reach up to 27.525 mA. Afterward, the research also discusses the electric field distribution in the entire space of the TECG, along with the electron distribution behavior caused by the electric field. Finally, after pointing out its shortcomings, the research provides guidance and prospects for future related work.

Numerical analysis of the Brewster-electrical duo-effect for multi-resonance tuning in THz absorber

The excitation and tuning of multiple resonances with narrow spectral width based on Brewster's effect is possible in an ultrathin dual-band terahertz absorber. The angular variation establishes a monotonic relation with the frequency of some generated resonances offering tunability. Moreover, burying a graphene ring resonator beneath the metallic ring splits the resonance for providing the triple narrow absorption windows. The electrical modulation offers the feature of independent tunability in the generated third absorption band. Thus, the frequency ratio of the upper to lower spectral absorption peak can be modulated by the electrically tunable Fermi energy of graphene. Engraving the graphene resonator also enhances the incident angle based tunability by affecting a greater number of Brewster generated resonance peaks. The narrow line shape of the triple band absorption can enable refractive index sensing and the detection of extraneous elements in localized analyte samples. The detection of imidacloprid pesticide in wheat flour is performed by the implemented sensor. The numerical analysis is done for the design and analysis of the absorber structures to report the above facts.