Despite its amazing quantitative successes and contributions to revolutionary technologies, physics currently faces many unsolved mysteries ranging from the meaning of quantum mechanics to the nature of the dark energy that will determine the future of the Universe. It is clearly prohibitive for the general reader, and even the best informed physicists, to follow the vast number of technical papers published in the thousands of specialized journals. For this reason, we have asked the leading experts across many of the most important areas of physics to summarise their global assessment of some of the most important issues. In lieu of an extremely long abstract summarising the contents, we invite the reader to look at the section headings and their authors, and then to indulge in a feast of stimulating topics spanning the current frontiers of fundamental physics from 'The Future of Physics' by William D Phillips and 'What characterises topological effects in physics?' by Gerard 't Hooft through the contributions of the widest imaginable range of world leaders in their respective areas. This paper is presented as a preface to exciting developments by senior and young scientists in the years that lie ahead, and a complement to the less authoritative popular accounts by journalists.
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Gerard 't Hooft et al 2024 Phys. Scr. 99 052501
S B Dugdale 2016 Phys. Scr. 91 053009
The concept of the Fermi surface is at the very heart of our understanding of the metallic state. Displaying intricate and often complicated shapes, the Fermi surfaces of real metals are both aesthetically beautiful and subtly powerful. A range of examples is presented of the startling array of physical phenomena whose origin can be traced to the shape of the Fermi surface, together with experimental observations of the particular Fermi surface features.
Jack Smith 2022 Phys. Scr. 97 122001
First conceptualised in Olaf Stapledon's 1937 novel 'Star Maker', before being popularised by Freeman Dyson in the 1960s, Dyson Spheres are structures which surround a civilisation's sun to collect all the energy being radiated. This article presents a discussion of the features of such a feat of engineering, reviews the viability, scale and likely design of a Dyson structure, and analyses details about each stage of its construction and operation. It is found that a Dyson Swarm, a large array of individual satellites orbiting another celestial body, is the ideal design for such a structure as opposed to the solid sun-surrounding structure which is typically associated with the Dyson Sphere. In our solar system, such a structure based around Mars would be able to generate the Earth's 2019 global power consumption of 18.35 TW within fifty years once its construction has begun, which itself could start by 2040 using biennial launch windows. Alongside a 4.17 km2 ground-based heliostat array, the swarm of over 5.5 billion satellites would be constructed on the surface of Mars before being launched by electromagnetic accelerators into a Martian orbit. Efficiency of the Dyson Swarm ranges from 0.74–2.77% of the Sun's 3.85 × 1026 W output, with large potential for growth as both current technologies improve, and future concepts are brought to reality in the time before and during the swarm's construction. Not only would a Dyson Swarm provide a near-infinite, renewable power source for Earth, it would also allow for significant expansions in human space exploration and for our civilisation as a whole.
Gerianne Alexander et al 2020 Phys. Scr. 95 062501
Sounds of Science is the first movement of a symphony for many (scientific) instruments and voices, united in celebration of the frontiers of science and intended for a general audience. John Goodenough, the maestro who transformed energy usage and technology through the invention of the lithium-ion battery, opens the programme, reflecting on the ultimate limits of battery technology. This applied theme continues through the subsequent pieces on energy-related topics—the sodium-ion battery and artificial fuels, by Martin Månsson—and the ultimate challenge for 3D printing, the eventual production of life, by Anthony Atala. A passage by Gerianne Alexander follows, contemplating a related issue: How might an artificially produced human being behave? Next comes a consideration of consciousness and free will by Roland Allen and Suzy Lidström. Further voices and new instruments enter as Warwick Bowen, Nicolas Mauranyapin and Lars Madsen discuss whether dynamical processes of single molecules might be observed in their native state. The exploitation of chaos in science and technology, applications of Bose–Einstein condensates and the significance of entropy follow in pieces by Linda Reichl, Ernst Rasel and Roland Allen, respectively. Mikhail Katsnelson and Eugene Koonin then discuss the potential generalisation of thermodynamic concepts in the context of biological evolution. Entering with the music of the cosmos, Philip Yasskin discusses whether we might be able to observe torsion in the geometry of the Universe. The crescendo comes with the crisis of singularities, their nature and whether they can be resolved through quantum effects, in the composition of Alan Coley. The climax is Mario Krenn, Art Melvin and Anton Zeilinger's consideration of how computer code can be autonomously surprising and creative. In a harmonious counterpoint, his 'Guidelines for considering AIs as coauthors', Roman Yampolskiy concludes that code is not yet able to take responsibility for coauthoring a paper. An interlude summarises a speech by Zdeněk Papoušek. In a subsequent movement, new themes emerge as we seek to comprehend how far we have travelled along the path to understanding, and speculate on where new physics might arise. Who would have imagined, 100 years ago, a global society permeated by smartphones and scientific instruments so sophisticated that genes can be modified and gravitational waves detected?
Anton Zeilinger 2017 Phys. Scr. 92 072501
The quantum physics of light is a most fascinating field. Here I present a very personal viewpoint, focusing on my own path to quantum entanglement and then on to applications. I have been fascinated by quantum physics ever since I heard about it for the first time in school. The theory struck me immediately for two reasons: (1) its immense mathematical beauty, and (2) the unparalleled precision to which its predictions have been verified again and again. Particularly fascinating for me were the predictions of quantum mechanics for individual particles, individual quantum systems. Surprisingly, the experimental realization of many of these fundamental phenomena has led to novel ideas for applications. Starting from my early experiments with neutrons, I later became interested in quantum entanglement, initially focusing on multi-particle entanglement like GHZ states. This work opened the experimental possibility to do quantum teleportation and quantum hyper-dense coding. The latter became the first entanglement-based quantum experiment breaking a classical limitation. One of the most fascinating phenomena is entanglement swapping, the teleportation of an entangled state. This phenomenon is fundamentally interesting because it can entangle two pairs of particles which do not share any common past. Surprisingly, it also became an important ingredient in a number of applications, including quantum repeaters which will connect future quantum computers with each other. Another application is entanglement-based quantum cryptography where I present some recent long-distance experiments. Entanglement swapping has also been applied in very recent so-called loophole-free tests of Bell's theorem. Within the physics community such loophole-free experiments are perceived as providing nearly definitive proof that local realism is untenable. While, out of principle, local realism can never be excluded entirely, the 2015 achievements narrow down the remaining possibilities for local realistic explanations of the quantum phenomenon of entanglement in a significant way. These experiments may go down in the history books of science. Future experiments will address particularly the freedom-of-choice loophole using cosmic sources of randomness. Such experiments confirm that unconditionally secure quantum cryptography is possible, since quantum cryptography based on Bell's theorem can provide unconditional security. The fact that the experiments were loophole-free proves that an eavesdropper cannot avoid detection in an experiment that correctly follows the protocol. I finally discuss some recent experiments with single- and entangled-photon states in higher dimensions. Such experiments realized quantum entanglement between two photons, each with quantum numbers beyond 10 000 and also simultaneous entanglement of two photons where each carries more than 100 dimensions. Thus they offer the possibility of quantum communication with more than one bit or qubit per photon. The paper concludes discussing Einstein's contributions and viewpoints of quantum mechanics. Even if some of his positions are not supported by recent experiments, he has to be given credit for the fact that his analysis of fundamental issues gave rise to developments which led to a new information technology. Finally, I reflect on some of the lessons learned by the fact that nature cannot be local, that objective randomness exists and about the emergence of a classical world. It is suggestive that information plays a fundamental role also in the foundations of quantum physics.
Ulrik L Andersen et al 2016 Phys. Scr. 91 053001
Squeezed light generation has come of age. Significant advances on squeezed light generation have been made over the last 30 years—from the initial, conceptual experiment in 1985 till today's top-tuned, application-oriented setups. Here we review the main experimental platforms for generating quadrature squeezed light that have been investigated in the last 30 years.
Kaj Sotala and Roman V Yampolskiy 2015 Phys. Scr. 90 018001
Many researchers have argued that humanity will create artificial general intelligence (AGI) within the next twenty to one hundred years. It has been suggested that AGI may inflict serious damage to human well-being on a global scale ('catastrophic risk'). After summarizing the arguments for why AGI may pose such a risk, we review the fieldʼs proposed responses to AGI risk. We consider societal proposals, proposals for external constraints on AGI behaviors and proposals for creating AGIs that are safe due to their internal design.
S Pfalzner et al 2015 Phys. Scr. 90 068001
The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today's solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.
Andrew R Hogan and Andy M Martin 2024 Phys. Scr. 99 055118
Both the Jaynes-Cummings-Hubbard (JCH) and Dicke models can be thought of as idealised models of a quantum battery. In this paper we numerically investigate the charging properties of both of these models. The two models differ in how the two-level systems are contained in cavities. In the Dicke model, the N two-level systems are contained in a single cavity, while in the JCH model the two-level systems each have their own cavity and are able to pass photons between them. In each of these models we consider a scenario where the two-level systems start in the ground state and the coupling parameter between the photon and the two-level systems is quenched. Each of these models display a maximum charging power that scales with the size of the battery N and no super charging was found. Charging power also scales with the square root of the average number of photons per two-level system m for both models. Finally, in the JCH model, the power was found to charge inversely with the photon-cavity coupling κ.
Michael G Raymer and Ian A Walmsley 2020 Phys. Scr. 95 064002
We review the concepts of temporal modes (TMs) in quantum optics, highlighting Roy Glauber's crucial and historic contributions to their development, and their growing importance in quantum information science. TMs are orthogonal sets of wave packets that can be used to represent a multimode light field. They are temporal counterparts to transverse spatial modes of light and play analogous roles—decomposing multimode light into the most natural basis for isolating statistically independent degrees of freedom. We discuss how TMs were developed to describe compactly various processes: superfluorescence, stimulated Raman scattering, spontaneous parametric down conversion, and spontaneous four-wave mixing. TMs can be manipulated, converted, demultiplexed, and detected using nonlinear optical processes such as three-wave mixing and quantum optical memories. As such, they play an increasingly important role in constructing quantum information networks.
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Jingjing Liu et al 2024 Phys. Scr. 99 065249
This paper studies super-resolution (SR) technique to reconstruct high-quality images for deep image analysis. Currently, the convolutional neural networks (CNNs) are well performing methods and the finding that random noise added in the network can have positive incentive effect, we innovatively propose a positive incentive CNNs. However, concerning the uncontrollable characteristic and lack consistency of deep network, we propose a novel framework that joins nonconvex model based on framelet and positive incentive CNN structure, which can impose consistency between the high-resolved image and the given low-resolution image, and depict image information by sparse representation. Furthermore, to overcome the challenge of computing the minimizer of the nonconvex problem, we use proximal linearized minimization (PLM) algorithm to convex the nonconvex term, then apply the alternating direction method of multipliers (ADMM) as the solver which can converge to a stationary point of the nonconvex model. The experimental outcomes on Set5, Set14, BSD100, Urban100, and real-world images demonstrate that the proposed approach outperforms the state-of-the-art methods in terms of peak signal to noise ratio (PSNR) value, structural similarity index (SSIM), and visual quality.
G Kadim and R Masrour 2024 Phys. Scr. 99 065988
Using spin-polarized GGA combined with TB-mBJ approach and Monte Carlo simulation, we systematically explore the electronic and magnetic properties of cubic Al1-xSixFe2Ge (x = 0, 0.25, 0.50, 0.75, and 1) compounds. Structural optimization in the ferromagnetic and ferrimagnetic state proves that the AlFe2Ge alloy is ferrimagnetic with an enhanced lattice constant of 3.6075 Å. Elastic constants and related mechanical quantities such as bulk modulus B, Zener anisotropy factor A and Cauchy pressure Cp were calculated. The calculated total magnetic moments decrease with increasing Si concentration. The total magnetic moments of AlFe2Ge and SiFe2Ge compounds are fully compatible with the Slater-Pauling rule. The results show that the studied compound has remarkable properties such as high magnetic entropy at low temperature 40 J.kg−1.K−1, metallicity and ferrimagnetism. Noting that ferrimagnetic compound is more suitable for spintronic devices than the ferromagnetic compound due to its lower leakage fields and favorable robustness of magnetism.
Z J Li et al 2024 Phys. Scr. 99 065119
A global multi-partite entanglement may place a constraint on the wave-particle duality. We investigate this constraint relation of the global entanglement and the quantitative wave-particle duality in tripartite systems. We perform quantum state tomography to reconstruct the reduced density matrix by using the OriginQ quantum computing cloud platform. As a result, we show that, theoretically and experimentally, the quantitative wave-particle duality is indeed constrained by the global tripartite entanglement. The present constraint relation can not only provide the foundational explanation for experimentally testing wave-particle duality, and also give the global entanglement a motivated physical meaning from the point of view of the quantitative wave-particle duality.
Fei-Yun Ding et al 2024 Phys. Scr. 99 065248
By using the reductive perturbation method, we obtained a nonlinear Schrödinger equation considering spin properties for a magnetized electron-positron plasmas. Several nonlinear wave were studied. The results indicate that various types of nonlinear waves exist in a magnetized electron-positron plasmas and they are spatially localized in both parallel and vertical directions to the external magnetized field direction. Additionally, the dependence of the wave amplitudes, wave width in both direction, group velocity of the envelop wave and the phase velocity of the background waves for these kinds of the nonlinear waves on the system parameters are all given in the present paper.
Hamza Kerrai et al 2024 Phys. Scr. 99 065986
In this study, we investigated the magnetic properties, magnetocaloric effect, magnetic energy product, and hysteresis behavior of Mn3AlN antiperovskite using Monte Carlo (MC) simulation techniques. We examined the effect of magnetic field on magnetic behavior. As the magnetic field values h increase, the amplitudes of both the specific heat peaks and the susceptibility also increase. For various external magnetic fields and temperatures, we obtained the adiabatic temperature change and the magnetic entropy change. The compound displayed a direct magnetocaloric effect. Furthermore, the relative cooling power (RCP) values for a magnetic field strength of 60 kOe are 117.54 J/kg. The hysteresis loops were used to calculate the energy product BH. These findings suggest that our material is an excellent fit for magnetic refrigeration and information storage applications.
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Amrinder Mehta et al 2024 Phys. Scr. 99 062006
Shape Memory Alloys (SMAs) are metallic materials with unique thermomechanical characteristics that can regain their original shape after deformation. SMAs have been used in a range of industries. These include consumer electronics, touch devices, automobile parts, aircraft parts, and biomedical equipment. In this work, we define the current state of the art in SMA manufacturing and distribution across the aerospace, healthcare, and aerospace industries. We examine the effect of manganese on the structure and mechanical and corrosive properties of SMA Cu-Al-Ni and discuss the importance of incorporating small and medium-sized enterprises in the study of cu-Al luminum. This research outlines a fundamental example of SME integration in the analysis of superelasticity, a critical instance of SMA activity. It can also serve as a reference for activities such as medical, aerospace, and other industries that target SMA-based equipment and systems. Also, they can be used to look at SMA activation and material upgrade mechanisms. These FEM simulations are advantageous in optimizing and promoting design in fields such as aerospace and healthcare. FEM simulations identify the stress and strength of SMA-based devices and structures. This would result in minimizing cost and usage and lowering the risk of damage. FEM simulations can also recognize the weaknesses of the SMA designs and suggest improvements or adjustments to SMA-based designs.
Kishore Kumar Venkatesan and Sathiyan Samikannu 2024 Phys. Scr. 99 062005
The incredible characteristics of nanomaterial and the benefits of optical fiber may be coupled to provide an exciting new platform for sensing applications. In recent years, there has been significant development and documentation of numerous gas and humidity sensors utilizing optical fiber based on 2D nanomaterials. This review primarily examines the most recent implementations in fiber optic gas and humidity sensing through 2D nanomaterials. With the help of nanomaterial, researchers may be able to fine-tune sensor parameters like thickness, roughness, specific area, refractive index, etc. This could make it possible for sensors to respond faster or to be more sensitive than standard sensors. Optical sensors are a family of devices that use different types of light interactions (i.e., photon-atom) to sense, analyze, and measure molecules for various purposes. Optical sensors are capable of detecting light, often within a narrow band of the electromagnetic spectrum (ultraviolet, visible, and infrared). A fiber optic sensor is an optical device that transforms the physical state of the object being measured into a quantifiable optical signal. Based on the photoelectric effect, the sensor detects light's wavelength, frequency, or polarisation and transforms it into an electric signal. This review describes the state-of-the-art research in this rapidly evolving sector, impacting sensor type, structure, synthesis, deposition process, detection range, sensitivity, response & recovery time, and application of 2D materials. Lastly, the problems that are currently in the way of using 2D materials in sensor applications are talked about, as well as what the future might hold.
Chithiika Ruby V and Lakshmanan M 2024 Phys. Scr. 99 062004
Liénard-type nonlinear oscillators with linear and nonlinear damping terms exhibit diverse dynamical behavior in both the classical and quantum regimes. In this paper, we consider examples of various one-dimensional Liénard type-I and type-II oscillators. The associated Euler–Lagrange equations are divided into groups based on the characteristics of the damping and forcing terms. The Liénard type-I oscillators often display localized solutions, isochronous and non-isochronous oscillations and are also precisely solvable in quantum mechanics in general, where the ordering parameters play an important role. These include Mathews-Lakshmanan and Higgs oscillators. However, the classical solutions of some of the nonlinear oscillators are expressed in terms of elliptic functions and have been found to be quasi-exactly solvable in the quantum region. The three-dimensional generalizations of these classical systems add more degrees of freedom, which show complex dynamics. Their quantum equivalents are also explored in this article. The isotonic generalizations of the non-isochronous nonlinear oscillators have also been solved both classically and quantum mechanically to advance the studies. The modified Emden equation categorized as Liénard type-II exhibits isochronous oscillations at the classical level. This property makes it a valuable tool for studying the underlying nonlinear dynamics. The study on the quantum counterpart of the system provides a deeper understanding of the behavior in the quantum realm as a typical -symmetric system.
Dennis Bonatsos et al 2024 Phys. Scr. 99 062003
Prolate to oblate shape transitions have been predicted in an analytic way in the framework of the Interacting Boson Model (IBM), determining O(6) as the symmetry at the critical point. Parameter-independent predictions for prolate to oblate transitions in various regions on the nuclear chart have been made in the framework of the proxy-SU(3) and pseudo-SU(3) symmetries, corroborated by recent non-relativistic and relativistic mean field calculations along series of nuclear isotopes, with parameters fixed throughout, as well as by shell model calculations taking advantage of the quasi-SU(3) symmetry. Experimental evidence for regions of prolate to oblate shape transitions is in agreement with regions in which nuclei bearing the O(6) dynamical symmetry of the IBM have been identified, lying below major shell closures. In addition, gradual oblate to prolate transitions are seen when crossing major nuclear shell closures, in analogy to experimental observations in alkali clusters.
Raghavendra Garlapally et al 2024 Phys. Scr. 99 062002
The present summarized study focused on Anodically fabricated TiO2 nanotubes array shows an exceptional physical and chemical properties due to their high surface area as well as thickness near to nano scale regimes. Crystallization of an amorphous TiO2 nanotube plays an important role when it comes to applications point of view. Studies revealed that a change in the annealing process resulted in an enhancement in their structure and properties. In this review, we mainly focus on various annealing techniques, their advantages and drawbacks over the other methods. Additionally, we have reported the effect of morphology and crystal structure of different annealed anodically grown TiO2 nanotubes. Therefore, the anodized TiO2 nanotubes array review will not only have applications in water splitting, hydrogen generation, solar cells but also a suitable potential candidate in the immense applications as micro/nano needles for drug delivery in biomedical as well as different electronic device/sensing approaches in aerospace sectors as well.
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Luo et al
Cobalt is an essential trace element in the human body that is vital for metabolism in living organisms. Insufficient or excessive intake of cobalt can lead to adverse effects. We prepared a europium-based metal–organic framework (Eu-MOF), NH4[Eu(sal)4(phen)2] (abbreviated as Eu-sal, sal = salicylic acid group, phen = 1,10-phenanthroline). Fluorescence investigations revealed that Eu-sal can efficiently and selectively identify Co2+ through a fluorescence quenching effect, with a quenching efficiency KSV and limit of detection (LOD) of 2.7 × 104 M−1 and 0.37 µM, respectively. In addition, Eu-sal also shows highly selective for CrO42− (KSV: 3.6 × 104 M−1; LOD: 0.27 μM). The quenching of Eu-sal fluorescence emission by Co2+ and CrO42− ions may be caused by spectral overlap, energy transfer, and competition. Furthermore, Eu-sal has good thermal and chemical stability. These results indicate that Eu-sal is a promising fluorescence probe for highly selective detection of Co2+ and CrO42− ions.
Hamzah et al
The compact modeling of NAND flash memories is crucial for integrated circuit designers to carry out efficient and precise circuit-level evaluations, particularly in the case of 3D NAND flash where the 3D geometry leads to significant parasitic coupling impacts on performance. In this work, we proposed a charge-based modeling approach for gate-all-around floating gate memory cells. The compact model is based on the derived unified charge control model where the mobile charge is explicitly solved. By solving the charge balance model and taking into account voltage-dependent parasitic capacitances for accurate coupling effects, the floating gate potential is accurately computed. The simulation results are validated with numerical TCAD simulation and showed good agreement with TCAD simulation. By solving the charge balance model and considering voltage-dependent parasitic capacitances for more accurate coupling effects, the floating gate potential is accurately calculated. The simulation results were validated using numerical TCAD simulation and showed good agreement, demonstrating that the floating gate potential is accurately estimated through the inclusion of voltage-dependent parasitic capacitances. Additionally, the results indicate that subthreshold degradation is caused by interface trap charge in the experimental device, and the proposed model successfully replicates experimental data.
Alonso-Herrera et al
The thermal conductivity for the wurtzite ZnO is determined in the temperature range from 300 to 1100 K by using parallel tempering molecular dynamics within the Green-Kubo approach and a classical Morse-Born-Mayer-Coulomb hybrid interaction potential. Compared to other previous calculations for the thermal conductivity of common crystals within the same Green-Kubo and molecular dynamics approach, the used parallel tempering scheme shows some appealing improvements in the calculation of the time self-correlation of the heat flux vector, although at the price of using a relatively large number of total computational steps. However, in spite of the the found improvements for the calculation of the self-correlation of the heat flux vector, some statistical problems on this point remain on the particular application of the method. Finally, despite the presence of a clear statistical noise, the obtained values and temperature trend of the calculated thermal conductivity shows the classical 1/T decaying behavior reported in previous works for wurtzite ZnO and other related semiconductor systems using the alternative Boltzmann transport equation theory.
Yan et al
The Helmholtz resonant structure with a rectangular extended neck is designed in this work to solve the low-frequency broadband sound absorption problem. Theoretical and finite element absorption models have been established and are used for low-frequency acoustic design. What makes it interesting is that all parameters of the rectangular extended neck Helmholtz resonator can be adjusted to shift the working frequency. Four coupling structures with different neck depths, neck opening areas, cavity cross-sectional areas, and cavity depths are respectively designed. Each of these structures exhibits multiple sound absorption coefficient peaks to enhance the low-frequency absorption capacity. The effectiveness of the coupling structure is further analyzed by examining the broadband acoustic absorption mechanism based on the particle vibration velocity distribution. It is found that cells with different acoustic impedance contribute differently to the sound absorption, and cells with longer necks provide better noise reduction at low frequencies. The experiment is verified in the impedance tube, and the result shows that the coupling structure with 9 cells and a cavity depth of only 4cm achieves an average sound absorption coefficient above 0.8 at 210-340 Hz, thus verifying the accuracy of the theoretical model. Overall, the Helmholtz resonant cavity acoustic structure with a rectangular extended neck proposed in this study has a simple structure with low-frequency broadband acoustic absorption performance, providing a new approach for designing low-frequency broadband acoustic structures.
Yıldız et al
This study was designed to examine the photoelectric device performances of cobalt-iron (CoFe) and cobalt-iron-nickel (CoFeNi) materials with good magnetic properties, specifically to investigate the effect of the Ni element on theelectrical properties. In this context, Al/CoFe/p-Si and Al/CoFeNi/p Si devices were produced by coating both materia- ls between the semiconductor and the metal using the RF sputtering method. First of all, to investigate the structural properties of the coated films, the content analysis was carried out by X-ray diffraction (XRD) analysis. To determine the photoelectrical properties of the produced devices, current-voltage and transient photocurrent measurements were performed and analyzed under different light intensities. It was determined that both devices are sensitive to light, with the sensitivity of the device with the CoFeNi interlayer being much higher. In addition, photocapacitance and photoconductivity measurements were carried out to examine the photocapacitor performance of the devices. As a result of the investigations, both current-voltage, photocurrent, and photo-capacitance/conductivity measurements showed that the device with the CoFeNi interface layer showed better performance than the device with the CoFe interface. Therefore, it has been determined that the Ni element has a positive effect on electrical properties. Additionally, the results obtained show that the prepared materials and produced devices can be used in photovoltaic applications.
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Xu Cao et al 2024 Phys. Scr. 99 065038
Although a titanium matrix modified with titanium dioxide nanotube (TNT) arrays can have anti-inflammatory effects in vitro, these effects are limited. In this study, the TNT surface was modified by electrodepositing graphene oxide (GO) to enhance the anti-inflammatory effect of the material. Scanning electron microscopy (SEM), Raman spectroscopy, and x-ray diffraction were used to characterize each of these materials. Cell Counting Kit-8 (CCK-8) was used to determine the cell proliferation status. Enzyme-linked Immunosorbent Assay (ELISA), immunofluorescence staining, and RNA sequencing were used to assess the regulation of inflammation in each group. Raman spectroscopy confirmed that GO was successfully loaded onto the surface. The SEM, ELISA, fluorescence staining, and RNA sequencing results indicated that TNT-GO can effectively inhibit the inflammatory response and induce the M2 polarization of macrophages. TNT-GO can weaken the surface inflammatory responses of materials, suppress the secretion of pro-inflammatory factors, and promote the M2 polarization of macrophages. These advantageous properties render TNT-GO a promising material for dental implants.
Nadir Kaplan et al 2024 Phys. Scr. 99 065975
The goal of this work is to determine how the rate of Ni deposition rates affect the structural characteristics that regulate the magnetization of Ni/Al multilayer thin films sputtered on flexible acrylic acetate polymer substrates. The films with a 5[Ni(20 nm)/Al(10 nm)] structure were gradually sputtered as different Ni deposition rates in the total thickness of 150 nm. With an increase in the rate of Ni deposition, the Ni contents increased from 61.5% to 69.6%. And, X-ray diffraction analysis verified that the films featured a face-centered cubic structure with variable peak intensities. Also, the scanning electron microscopy surface morphology analyses revealed that variations in the film surfaces were a result of the deposition rates. For magnetic measurements, the differences in the structural analysis were observed to cause a notable variation in saturation magnetization, MS, and coercivity, HC values. Accordingly, MS values increased consistently between 359.0 and 389.7 emu cm−3, but HC values decreased from around 34–32 to 28 Oe with the increase in Ni deposition rate from 0.02 to 0.10 nm s−1. It is also observed that when the Ni layers are generated at very fast deposition rates, the Ni/Al multilayer films have a high MS/HC ratio, which is significant for magnetic sensors. It has been concluded that the magnetisation of Ni/Al multilayer thin films can be controlled by the structural properties adjusting the Ni deposition rate.
Aeriyn D. Ahmad et al 2024 Phys. Scr.
In this study, we assess the practicality of using Polyacrylonitrile (PAN) as a saturable absorber (SA) to generate Q-switched pulses in an erbium-doped fibre laser (EDFL) cavity. A successful combination of PAN, a resin material, and polyvinyl alcohol (PVA) resulted in the formation of a SA film. This film was utilised to generate stable Q-switched pulses operating in a long-wavelength band of 1572 nm. The greatest repetition rate achieved was 66.1 kHz, while the minimum pulse width was 2.43 µs. The maximum pulse energy was achieved at 52 nJ and measured at a pump power of 175.9 mW. To the best of our knowledge, this study is the first report of EDFL passive Q-switching employing a PAN absorber.
Martin Beneke et al 2024 Phys. Scr. 99 065240
The inverted pendulum is a mechanical system with a rapidly oscillating pivot point. Using techniques similar in spirit to the methodology of effective field theories, we derive an effective Lagrangian that allows for the systematic computation of corrections to the so-called Kapitza equation. The derivation of the effective potential of the system requires non-trivial matching conditions, which need to be determined order by order in the power-counting of the problem. The convergence behavior of the series is investigated on the basis of high-order results obtained by this method. The results from this analysis can be used to determine the regions of parameter space, in which the inverted position of the pendulum is stable or unstable to high precision.
Shubin Yan et al 2024 Phys. Scr. 99 065541
In this study, a nanoscale refractive index sensor structure is proposed, which is realised using a metal-insulator-metal (MIM) waveguide and a grooved circular ring with double disk cavity (GRDD) structure coupled to each other. The finite element method (FEM) was used to analyze and investigate the effects of the variations of each structural parameter on the transmittance spectra and the comprehensive performance of the sensor. Based on the simulation results, the optimum sensitivity parameter of the sensor structure is 2800 nm R−1IU−1 with a figure of merit (FOM) value of 51.9 RIU−1. The sensor structure is capable of being used in biomedical field with sensitivities of and respectively, for detecting hemoglobin of blood types A, B, and O, and for detecting glucose concentration.
Ibrahim Elbatal et al 2024 Phys. Scr. 99 065231
In this research, we investigate a brand-new two-parameter distribution as a modification of the power Zeghdoudi distribution (PZD). Using the inverse transformation technique on the PZD, the produced distribution is called the inverted PZD (IPZD). Its usefulness in producing symmetric and asymmetric probability density functions makes it the perfect choice for lifetime phenomenon modeling. It is also appropriate for a range of real data since the relevant hazard rate function has one of the following shapes: increasing, decreasing, reverse j-shape or upside-down shape. Mode, quantiles, moments, geometric mean, inverse moments, incomplete moments, distribution of order statistics, Lorenz, Bonferroni, and Zenga curves are a few of the significant characteristics and aspects explored in our study along with some graphical representations. Twelve effective estimating techniques are used to determine the distribution parameters of the IPZD. These include the Kolmogorov, least squares (LS), a maximum product of spacing, Anderson-Darling (AD), maximum likelihood, minimum absolute spacing distance, right-tail AD, minimum absolute spacing-log distance, weighted LS, left-tailed AD, Cramér-von Mises, AD left-tail second-order. A Monte Carlo simulation is used to examine the effectiveness of the obtained estimates. The visual representation and numerical results show that the maximum likelihood estimation strategy regularly beats the other methods in terms of accuracy when estimating the relevant parameters. The usefulness of the recommended distribution for modelling data is illustrated and displayed visually using two real data sets through comparisons with other distributions.
L Bolzoni and F Yang 2024 Phys. Scr. 99 065024
X-ray diffraction (XRD) is routinely used to characterise Ti alloys, as it provides insight on structure-related aspects. However, there are no dedicated reports on its accuracy are available. To fill this gap, this work aims at examining the benefits and limitations of XRD analysis for phase identification in Ti-based alloys. It is worth mentioning that this study analyses both standard and experimental Ti alloys but the scope is primarily on alloys slow cooled from high temperature, thus characterised by equilibrium microstructures. To be comprehensive, this study considers the all spectrum of Ti alloys, ranging from alpha to beta Ti alloys. It is found that successful identification and quantification of the phases is achieved in the majority of the different type of Ti-based alloys. However, in some instances like for near-alpha alloys, the output of XRD analysis needs to be complemented with other characterisation techniques such as microscopy to be able to fully characterise the material. The correlation between the results of XRD analysis and the molybdenum equivalent parameter (MoE), which is widely used to design Ti alloys, was also investigated using structural-analytical models. The parallel model is found to be the best to estimate the amount of β-Ti phase as a function of the MoE parameter.
Davide Stirpe et al 2024 Phys. Scr.
We study here the semiclassical dynamics of a superconducting circuit constituted by two Josephson junctions in series, in the presence of a voltage bias. We derive the equations of motion for the circuit through a Hamiltonian description of the problem, considering the voltage sources as semi-holonomic constraints. We find that the dynamics of the system corresponds to that of a planar rotor with an oscillating pivot. We show that the system exhibits a rich dynamical behaviour with chaotic properties and we present a topological classification of the cyclic solutions, providing insight into the fractal nature of the dynamical attractors.
Vu Thanh Tung et al 2024 Phys. Scr.
A time-of-flight–based ranging system constructed by an intensity-modulated light source and photodetectors (PDs) is proposed. In the proposed system, the carrier wave, which comprises two cosine waves with different frequencies in the megahertz range, is reconstructed from a few samples obtained by PDs with a kilohertz sampling rate using the compressive sensing technique. This allows the system to observe the distance with very high accuracy and it also extends the measurement range while maintaining the accuracy of an existing system that utilizes a single-frequency carrier.
Bryan J Dalton 2024 Phys. Scr.
In this paper we consider the description by a general Bell-type non-local hidden variable theory of bipartite quantum states with two observables per sub-system. We derive Bell inequalities of the Collins-Gisin.-Liden-Massar-Popescu type which involve combinations of the probabilities of related outcomes for measurements for the four pairs of sub-system observables. It is shown that the corresponding quantum theory expressions violate the Bell inequalities in the case of the maximally entangled state of the bipartitite system. The CHSH Bell inequality is also derived from this general CGLMP Bell-type non-local hidden variable theory. This shows that quantum theory can not be underpinned by a Bell-type non-local hidden variable theory. So as a general Bell-type local hidden variable theory has already been shown to conflict with quantum theory, it follows that quantum theory can not be understood in terms of any CGLMP Bell-type hidden variable theory - local or non-local.