Hasil untuk "Electricity and magnetism"

R. Day, D. K. Bediako, M. Rezaee et al.

Crystalline, electrically conductive, and intrinsically porous materials are rare. Layered two-dimensional (2D) metal–organic frameworks (MOFs) break this trend. They are porous crystals that exhibit high electrical conductivity and are novel platforms for studying fundamentals of electricity and magnetism in two dimensions. Despite demonstrated applications, electrical transport in these remains poorly understood because of a lack of single crystal studies. Here, studies of single crystals of two 2D MOFs, Ni3(HITP)2 and Cu3(HHTP)2, uncover critical insights into their structure and transport. Conductivity measurements down to 0.3 K suggest metallicity for mesoscopic single crystals of Ni3(HITP)2, which contrasts with apparent activated conductivity for polycrystalline films. Microscopy studies further reveal that these MOFs are not isostructural as previously reported. Notably, single rods exhibit conductivities up to 150 S/cm, which persist even after prolonged exposure to ambient conditions. These single crystal studies confirm that 2D MOFs hold promise as molecularly tunable platforms for fundamental science and applications where porosity and conductivity are critical.

Mei Liu, Yijing Meng, Siguang Ouyang et al.

Spontaneous recovery frequently proves maladaptive or insufficient because the plasticity of the injured adult mammalian central nervous system is limited. This limited plasticity serves as a primary barrier to functional recovery after brain injury. Neuromodulation technologies represent one of the fastest-growing fields in medicine. These techniques utilize electricity, magnetism, sound, and light to restore or optimize brain functions by promoting reorganization or long-term changes that support functional recovery in patients with brain injury. Therefore, this review aims to provide a comprehensive overview of the effects and underlying mechanisms of neuromodulation technologies in supporting motor function recovery after brain injury. Many of these technologies are widely used in clinical practice and show significant improvements in motor function across various types of brain injury. However, studies report negative findings, potentially due to variations in stimulation protocols, differences in observation periods, and the severity of functional impairments among participants across different clinical trials. Additionally, we observed that different neuromodulation techniques share remarkably similar mechanisms, including promoting neuroplasticity, enhancing neurotrophic factor release, improving cerebral blood flow, suppressing neuroinflammation, and providing neuroprotection. Finally, considering the advantages and disadvantages of various neuromodulation techniques, we propose that future development should focus on closed-loop neural circuit stimulation, personalized treatment, interdisciplinary collaboration, and precision stimulation.

Genaro Zavala, K. Zuza, J. Guisasola et al.

This conceptual understanding article is part of a series where we analyze the recognition and conversion of representations of the electric field concept; in this article, we present the case of algebraic notation. We conducted a study with introductory and upper-division physics students taking electricity and magnetism courses in a large private Mexican university to learn how students recognize the electric field’s main characteristics in the algebraic notation of the field and how they convert to and from different representations. We refer to the theory of registers of semiotic representations as a theoretical framework and use a phenomenographic approach to analyze data. We explored students’ recognition and conversion abilities through interpretation and construction tasks for the electric field’s algebraic notation. We found that the main difficulties of interpreting and constructing the algebraic notation are related to separating the mathematical expression from the situation’s physical meaning. Sometimes, students referred only to the physical meaning without using algebraic notation. In other cases, they construct algebraic notation without explicitly describing the physical meaning. Another source of difficulty is the treatment process because some students make mistakes or misinterpretations that they carry throughout. We recommend that introductory and upper-division electricity and magnetism instructors and physics education researchers in higher education be aware of the difficulties that some interpretation and construction tasks may present to students learning the electric field concept.

T. Mori

S. Essaoud, M. Radjai, A. Bouhemadou et al.

Esmeralda Campos, Philip Troskot, Wolfgang Aschauer et al.

In physics education, the electricity and magnetism high school curriculum in Austria includes learning abstract concepts, such as static electric and magnetic fields, and their interactions with matter. This is different to learning about electric circuits at middle-school level, which has been researched extensively. The difficulties in learning such abstract concepts have been studied mostly at undergraduate introductory and advanced levels, with a few exceptions in high school. The objective of this study is to diagnose Austrian high school students’ understanding of electric and magnetic fields and interactions and identify their most common difficulties. To achieve this objective, we conducted a study with a mixed methods approach with a concurrent triangulation design. The participants were 265 high school students in Austria, who answered a multiple-choice questionnaire and open-ended questions on several topics of electricity and magnetism. We found that students have difficulties with using and interpreting the field representations, such as creating hybrid representations of field lines and vector arrows. Both in the quantitative and qualitative results, the confusion between electricity and magnetism was evident: in electricity, students would treat the electric field as magnetic field, and in magnetism, the students would treat magnets as charged poles.

Xun Sun, Peihong Ma, Jun Xu et al.

The light absorption capacity has a crucial effect on photocatalytic activity as one of the essential properties of photocatalysts. Herein, a series of tetragonal phase Ba[Formula: see text]MxTiO3 (M = Eu, Ce, Sm, Gd, La) photocatalysts were synthesized by a hydrothermal method. Among rare earth dopants, Ba[Formula: see text]SmxTiO3 exhibits a smaller grain size ([Formula: see text] [Formula: see text]nm), and provides more sites for the adsorption and activation of CO2, compared to pristine BaTiO3. The introduction of Sm ion extends the optical response range of BaTiO3 to the visible region and reduces the band gap. Under 300[Formula: see text]W Xe lamp, the 4[Formula: see text]h CO and CH4 yields of Ba[Formula: see text]SmxTiO3 catalysts increased to [Formula: see text]mol[Formula: see text] ⋅ g[Formula: see text] and 0.46[Formula: see text] [Formula: see text]mol[Formula: see text] ⋅ [Formula: see text]g[Formula: see text], respectively, which were 1.89 and 0.76 times that of the pristine BaTiO3. This work provides insights for designing rare earth-doped photocatalysts and realizing efficient conversion of solar fuel.

ZUO Bingyu, SHI Lili, SONG Jia et al.

Accurate and reliable diagnosis of cervical cancer is crucial for effective clinical treatment and prognosis evaluation. Given the low sensitivity of existing serum estrogen and tumor markers in assessing lesion features like parauterine invasion and lymph node metastasis, this study proposes a diagnostic method integrating multi-phase dynamic enhanced magnetic resonance imaging (DCE-MRI). Firstly, serum estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), glycochain antigen 125 (CA125), glycochain antigen 19-9 (CA19-9) and DCE-MRI were detected to analyze the correlation between cervical cancer stage and serum levels of E2, FSH, LH, CA125 and CA19-9. Then, cervical biopsy results were used as the gold standard to analyze the diagnostic accuracy of DCE-MRI for cervical deep muscle invasion and lymph node metastasis. Finally, the serum levels of E2, FSH, LH, CA125, CA19-9, DCE-MRI diagnosis and combined diagnosis of cervical cancer were evaluated based on the receiver operating characteristic (ROC) curve. The experimental results showed that the AUC of combined diagnosis was 0.908, indicating that the combined diagnosis method effectively distinguished benign and malignant cervical lesions. Furthermore, DCE-MRI parameters Ktrans and Kep enriched the feature information, thereby improving the detection accuracy of lesions. This provides a novel approach for differentiating between benign and malignant cervical cancer and for determining its clinical stage.

Jana Tothova, Jan Busa, Vladimir Lisy

Based on the Zwanzig-Caldeira-Legget theory generalized to systems under the influence of a static magnetic field, we obtain equations of motion for the Brownian particle (BP) and oscillators constituting the bath in which the BP is embedded. The equations are of the type of a generalized Langevin equation, which accounts for the frictional memory of the system. The BP is assumed to be charged while the bath particles are neutral. They thus do not directly respond to the external field, but their interaction with the BP leads to changes in the bath state. Using the solution of the equations found, we calculate the average bath angular momentum and show that it persists for long times when the system is assumed to reach equilibrium. This indicates a possible violation of the Bohr-van Leeuwen theorem for baths consisting of charged particles. However, this must be confirmed by a substantial generalization of the presented model when the bath particles feel the external field, which affects the memory in the dynamics of the system.

Alex J. Vernon, Konstantin Y. Bliokh

Geometric phases play an enormous role in optics and are generally associated with the evolution of light's polarization state on the Poincaré sphere, or its spin on the sphere of spin directions. Here we put forward a new kind of optical geometric phase that appears exclusively in nonparaxial light, resulting from cyclic changes to the relative amplitude and phase between the electric and magnetic fields. This phase is naturally represented on a recently introduced `electric-magnetic' sphere.

W. Feng, Peng Yabin, Zhang Ling

This study aims to explore novel properties of phosphorus (P) to zinc (Zn) elements. On the basis of previous work, we have explored the properties of elements ranging from H to Si. And the chemical elements belong layered, with P to Zn defined as the fourth layer to be researched using a contemporary industrial perspective. Since the late 19th century, there has been a progression in the application of electricity and magnetism to motor technology, leading to the evolution of computer systems capable of receiving, processing, and displaying external signals. These functionalities are recognized as attributes of the P element, serving as sensor modules for energy conversion. Subsequently, the establishment of a global production system through the utilization of the Internet and the Internet of Things has facilitated the growth of the biomedical industry within a vast industrial framework. This framework is characterized as the essence of the S element, functioning as an amplifier module for energy conversion. These 16 elements perform higher-level functions and can be seen as various processes for energy conversion in electromagnetic equipment, exemplified by biological signal transduction. They correspond to semiconductor chip fields such as from sensors and amplification circuits to displays and printing. This exploration is poised to enhance comprehension of the distinctive properties inherent in these elements.

Nathaniel D. Hidalgo, Monaliza L. Lachaona

Physics is the discipline that studies the principles of matter and energy, as well as their interactions. Mechanisms, electricity and magnetism, heat and thermodynamics, optics, and acoustics are among the fundamental concepts in Physics. Each of these conceptions has its own set of fields and fundamental laws. Furthermore, the researchers utilized purposive sampling in selecting the participants. Quasi-experimental research design was used in the study. Two groups were determined in the study, the control and experimental group. The control group used a lecture/traditional method while the experimental group had an intervention. The study utilized statistical tools to support the data gathered. Using the Mean test, results revealed that . The Paired sample t-test strongly indicates that the improvement in students’ performance from pretest to posttest is statistically significant. Paired sample t-test is also utilized to determine if there is a significant difference in the mean pretest and posttest score of each of the two groups. Thus, the results of the control group revealed that the null hypothesis is rejected. The Eta squared is administered and the results confirm that the intervention (GoC strategy) had a large effect on student performance. The Game of Cards (GoC) was created to assist students grasp and recall basic physics ideas while also improving their problem-solving skills. Card games can be fun and engaging ways to promote physics instruction at all levels of education. The activities of Game of Cards (GoC) are as follows: a. Guide Card, B. Activity Card, and c. Assessment Card. The intervention has steps with activities regarding Boyle’s and Charles’s Gas Laws, a specialized topic for Grade 10 students, that build on each other to produce a students-centered educational resources as well as a way of evaluation. Teachers may also consider adapting the strategy for other topics to see if similar improvements can be achieved.

Xiaoyu Zhou, Yongqiang Zhao, Jianqiang Jin et al.

Aiming at the problems that electric cylinders have complex structures, large volumes, and low efficiency, making them unsuitable for high-precision applications in robot linear joint modules, this paper designs a high-precision linear-driven robotic joint system and proposes a new method for integrating the motor rotor with a long nut. Through theoretical analysis of the working mechanism and structure of the electromagnetic linear actuator, a multi-field coupled mathematical model involving mechanics, electricity, and magnetism is established. A co-simulation test platform based on Simulink-Adams is built to verify the reliability of the system. Based on MATLAB/Simulink, a dual-loop proportional-integral-derivative (PID) control algorithm and a sliding-mode variable-structure control algorithm with a nonlinear extended state observer are designed and simulated, enabling the linear actuator to adjust its stroke and frequency according to different operating conditions. Simulation results show that the proposed control algorithms can meet the variable operating condition requirements of the linear joint actuator, and the motion is smooth under loaded conditions. This study provides a new approach for the research on lightweight, high-energy-efficiency, and high-precision linear driving and control technologies for robotic linear joints.

Iresh Jean C. Lumapas, Elesar V. Malicoban, Edna B. Nabua et al.

Physics is essential for understanding natural phenomena and advancing technological innovation. However, its abstract concepts and heavy reliance on mathematics present major learning barriers. This study aimed to determine the mastery levels of Grade 10 learners in Physics competencies to serve as a basis for designing strategic interventions using multimedia-enhanced reading materials. A Research and Development (R&D) design combined with a quasi-experimental approach was employed. Data were gathered using a validated 40-item Competency Level Test in Physics (CLTP) administered to 72 conveniently sampled Grade 10 learners from Mindanao Mission Academy, Misamis Oriental. Results indicated a majority of students (90.3%) did not meet expectations, with Waves and Electricity and Magnetism topics recording the lowest mastery levels. Based on the findings, the study recommends designing multimedia-enhanced reading materials to improve visualization, engagement, and understanding of abstract concepts. This intervention could enhance students’ performance and confidence in Physics.

Chunhui Song, Xu Cao, Xuedong Gao et al.

Electro-dehydration constitutes a crucial stage in crude oil dehydration due to its high efficiency, low energy consumption, broad applicability, and strong compatibility. While electromagnetic coupled fields offer superior dehydration efficiency compared to single electric fields, the dehydration mechanism of emulsions and dynamic characteristics of charged droplets under coupled fields remain unclear. This study employs numerical simulation software to establish a twodimensional model of charged droplets in emulsions, analyzing motion behavior through multiphysics coupling of two-phase flow, electricity, and magnetism. Results indicate that magnetic field addition weakly suppresses lateral motion under DC fields while promoting longitudinal motion and accelerating settling velocity, with electric fields exerting significantly greater influence than magnetic fields. Both lateral and longitudinal displacements scale positively with larger droplet radii. Furthermore, electric field intensity must coordinate with magnetic flux density and droplet size distribution. Based on droplet dynamics under coupled fields, an optimal polaritydependent electromagnetic configuration is proposed.

A. Elakkiya, M. Thiruppathiraja, B. N. Aryalekshmi et al.

A compact and modest triple-band metamaterial absorber (MMA) has been projected at terahertz (THz) frequencies with polarization-insensitive characteristics. Unlike conventional absorbers that have polarization-sensitive or polarization- insensitive behavior of MMA, the proposed device exhibits extra, polarization- controllable behaviour. This is achieved by the single top patch which is formed by grouping of two triangles. When the impact beam field of electricity (e-field) is chosen across the equal direction, three peak forms of absorption are mostly acquired; when the field of charge is chosen along the straight direction, three more spots are subsequently identified. This triple-band terahertz absorber is made up of a metallic basis on the bottom plate and a star-shaped patch on the top. The top model and the bottom ground plate were separated by a 0.125 mm -thick dielectric polyimide substrate. Electric current, magnetism, and area current distributions are used to analyse the physical mechanism of the polarization-controlled MMA. The polarisation type and digestion process in the present investigation were compared with those described in other studies. For large incidence degrees and polarisation angles up to 90 facets, the intended structure performs well. The selection, detection, maintenance, and functionality of polarization-sensitive gadgets should all be broadly applicable.

K. H., Aghaeiboorkheili, M.

In the history of physics, one of the deepest integrations that classically combined the phenomena of magnetism, optics and electricity into one theoretical structure is represented by Maxwell’s equations. This analysis gives a thorough mathematical formulation of the four fundamental equations elegantly. It provides a deeper understanding beginning from their historical basis in the works of Faraday, Gauss and Ampère and finishing in Maxwell’s vital input – the displacement current. We illustrate how these four equations beautifully surface from experimental laws when united with advanced vector calculus via comprehensive mathematical analysis. A disclosure that changed the concept of light is a consequence of Maxwell’s equations which has surpassed classical electromagnetism that led immediately to the forecast of electromagnetic waves. James C. Maxwell, when synthesizing magnetic and electricity, he has proven that light alone is an electromagnetic phenomenon. Today, in this modernized world, Maxwell’s equation has become the basis for electronic and electrical engineering. Nevertheless, examined here are some of their restrictions, notably in relativistic contexts and quantum mechanical where more enhanced theories become crucial. This analysis goals to give both thorough mathematical treatment and a well-defined understanding of the foundation equations of theoretical physics.

E. L. Tan

It has been widely accepted that Maxwell's equations have provided unification of electricity, magnetism and light. This paper asserts that the equations for the time-independent case have not unified electrostatics and magnetostatics so far. They only remain separated as two distinct sets of equations along with their solutions of Coulomb's and Biot-Savart laws for electric and magnetic fields respectively. Using the single electric field-impulse instead of traditional fields and/or potentials, we present the unification of both electrostatics and magnetostatics via single second-order equation. Such second-order equation is readily extendable to wave equation for electrodynamics. The wave equation or its first-order field-impulse equations would find usefulness in applications of classical/quantum electromagnetics and facilitate computational electromagnetics.

Dovine Dukru, Bhaskarjyoti Deka, Bamdeb Dey et al.

This study investigates the mathematical modeling of impermeable fluid motion that conducts electricity, focusing on the effects of magnetism and chemical interactions on thermal energy, mass transfer, viscosity dissipation, and Soret-Dufour phenomena. These interactions are vital for advancements in technology, geophysical sciences, and biology, particularly in magnetohydrodynamics (MHD). The research describes the governing equations for momentum and energy conservation under varying magnetic fields and performs a numerical analysis of flow behavior influenced by viscous dissipation on a semi-infinite surface. The study employs a set of nonlinear coupled partial differential equations (PDEs) under specific boundary conditions, using a similarity transformation to convert these PDEs into simpler ordinary differential equations (ODEs). The resulting first-order simultaneous equations are solved using the boundary value solution (BVP-4c) technique in MATLAB. Results are illustrated through visual representations showing the impact of various parameters on velocity, temperature, and concentration contours, as well as variations in shear stress, Nusselt number, and Sherwood number coefficients. The primary aim is to explore the magnetic parameter (D) and stretching degree (n) concerning heat and mass transfer and chemical reaction characteristics such as Soret amount (Sr) and Dufour number. The findings reveal that changes in the magnetic field significantly affect heat and mass transport properties and enhance the efficiency of these processes in industrial and natural contexts. This study innovatively incorporates viscosity dissipation and chemical interactions into the MHD framework, thereby improving the predictive capability of fluid dynamics models in complex scenarios.

Junyao Yuan, Xun Dong, Ying Zhou et al.

Long-stator Linear Synchronous Motor (LSLSM) is the core component of maglev trains. But the strong background noise generated by its complex operating environment often hides the stator winding damage characteristics, which makes it difficult to detect the stator turn-to-turn insulation damage status in time. This paper presents a method based on Iterative Adaptive Multiple Synchronous Compression of Transform (IAMST) and Deep Residual Convolutional Neural Network (DRS-CNN) for LSLSM stator winding fault detection. Firstly, the coupling model of a normal-conducting high-speed magnetic levitation machine-electricity-magnetism is constructed, and the accurate diagnosis of faults is realized through the analysis of multi-physical field coupling. Second, IAMST is utilized for energy aggregation to enhance the time-frequency (TF) resolution, and a TF representation is constructed to facilitate feature representation. Finally, DRS-CNN combines deep residual learning with Channel Attention Mechanism (ECA), which is used to further mine advanced features to identify the degree of turn-to-turn short-circuit faults. The experimental results show that this method effectively overcomes the limitation of traditional time-frequency analysis methods, which have difficulty extracting fault features in a noisy environment. It has solved the problems such as poor accuracy caused by directly adding signals to the network, the increase in the number of network layers, and the poor interpretability. It can accurately identify the severity of different short-circuit faults, providing an efficient and reliable solution for the detection of stator winding faults in the LSLMS in maglev trains.