bluuebunny/crossref_metadata_2025 huggingface dataset:
Vasculature-on-a-chip technologies as platforms for advanced studies of bacterial infections
Authors: Gaudreau Lily Isabelle , Stewart Elizabeth J.
Published: March 2024

Bacterial infections frequently occur within or near the vascular network as the vascular network connects organ systems and is essential in delivering and removing blood, essential nutrients, and waste products to and from organs. In turn, the vasculature plays a key role in the host immune response to bacterial infections. Technological advancements in microfluidic device design and development have yielded increasingly sophisticated and physiologically relevant models of the vasculature including vasculature-on-a-chip and organ-on-a-chip models. This review aims to highlight advancements in microfluidic device development that have enabled studies of the vascular response to bacteria and bacterial-derived molecules at or near the vascular interface. In the first section of this review, we discuss the use of parallel plate flow chambers and flow cells in studies of bacterial adhesion to the vasculature. We then highlight microfluidic models of the vasculature that have been utilized to study bacteria and bacterial-derived molecules at or near the vascular interface. Next, we review organ-on-a-chip models inclusive of the vasculature and pathogenic bacteria or bacterial-derived molecules that stimulate an inflammatory response within the model system. Finally, we provide recommendations for future research in advancing the understanding of host–bacteria interactions and responses during infections as well as in developing innovative antimicrobials for preventing and treating bacterial infections that capitalize on technological advancements in microfluidic device design and development.
A universal inverse design methodology for microfluidic mixers
Authors: Zhang Naiyin , Sun Taotao , Liu Zhenya , Zhang Yidan , Xu Ying , Wang Junchao
Published: March 2024

The intelligent design of microfluidic mixers encompasses both the automation of predicting fluid performance and the structural design of mixers. This article delves into the technical trajectory of computer-aided design for micromixers, leveraging artificial intelligence algorithms. We propose an automated micromixer design methodology rooted in cost-effective artificial neural network (ANN) models paired with inverse design algorithms. Initially, we introduce two inverse design methods for micromixers: one that combines ANN with multi-objective genetic algorithms, and another that fuses ANN with particle swarm optimization algorithms. Subsequently, using two benchmark micromixers as case studies, we demonstrate the automatic derivation of micromixer structural parameters. Finally, we automatically design and optimize 50 sets of micromixer structures using the proposed algorithms. The design accuracy is further enhanced by analyzing the inverse design algorithm from a statistical standpoint.
Dual-wavelength terahertz two-dimensional phase gratings based on all dielectric metasurfaces
Authors: Ren Yuan , Luo ZhengHeng , Xie GuoAo , Liu Dong , Zhou KangMin , Miao Wei , Zhang Wen , Shi ShengCai
Published: March 2024

Efficient and accurate phase gratings hold immense significance in the realization of large format heterodyne array receivers at terahertz frequencies. Metallic phase gratings have made substantial advancements in terms of operating wavelength and the number of diffraction beams. Like most other diffractive optical devices, metallic phase gratings are primarily optimized to operate at one specific wavelength. Metasurfaces compositing arrays of subwavelength nanostructures have been demonstrated with various optical functions, by freely modifying the polarization, phase, and amplitude of light. In this study, we present an approach to create a multi-wavelength phase grating compositing segments that incorporate multiple nanostructures. The resulting transmission phase grating not only exhibits uniform diffraction beams (2 × 2) but also achieves the same diffraction angles at both 1.31 and 2.7 THz. The measured total power efficiency of the diffraction beam pattern is 53.2% for 1.31 THz and 42.4% for 2.7 THz. These devices can be applied in terahertz astronomical observations and fluorescence microscopy applications, where multi-wavelength operation is necessary.
Single-event burnout in homojunction GaN vertical PiN diodes with hybrid edge termination design
Authors: Senarath A. S. , Islam S. , Sengupta A. , McCurdy M. W. , Anderson T. , Jacobs A. , Kaplar R. , Ball D. R. , Zhang E. X. , Pantelides S. T. , Reed R. A. , Ebrish M. A. , Fleetwood D. M. , Caldwell J. D. , Schrimpf R. D.
Published: March 2024

GaN devices play a major role in modern electronics, providing high-power handling, efficient high-frequency operation, and resilience in harsh environments. However, electric field crowding at the edge of the anode often limits its full potential, leading to single-event effects (SEEs) at lower bias voltages under heavy ion radiation. Here, we report on the performance of homojunction GaN vertical PiN diodes with a hybrid edge termination design under heavy ion irradiation, specifically, oxygen ions, chlorine ions, Cf-252 fission fragments, and alpha particles from an Am-241 source. The unique hybrid edge termination (HET) design provides better electric field management, preventing breakdown from occurring at the edge of the anode at lower voltages. The results of this study reveal that these devices exhibit excellent tolerance to 12-MeV oxygen and 16-MeV chlorine ions, owing to their low linear energy transfer (LET) and range in GaN. However, single-event burnout (SEB) is observed during the Cf-252 exposure at about 50% of the diodes' electrical breakdown voltage due to the presence of higher LET and longer-range ions. Optical and scanning electron microscopy (SEM) reveal that the damage that caused by SEB lies close to the center of these devices rather than the anode edge. Devices with junction termination extension (JTE) instead of HET edge termination also show similar SEB when irradiated with Cf-252 fission fragments. Physical damage due to SEB occurs at the edge of the anode for these devices. These comparative results show the benefits of HET for enhancing the resistance of GaN-based PiN diodes to heavy ion irradiation.
Efficient termination of cardiac arrhythmias using optogenetic resonant feedback pacing
Authors: Hussaini S. , Mamyraiym Kyzy A. , Schröder-Schetelig J. , Lädke S. L. , Venkatesan V. , Diaz-Maue L. , Quiñonez Uribe R. A. , Richter C. , Biktashev V. N. , Majumder R. , Krinski V. , Luther S.
Published: March 2024

Malignant cardiac tachyarrhythmias are associated with complex spatiotemporal excitation of the heart. The termination of these life-threatening arrhythmias requires high-energy electrical shocks that have significant side effects, including tissue damage, excruciating pain, and worsening prognosis. This significant medical need has motivated the search for alternative approaches that mitigate the side effects, based on a comprehensive understanding of the nonlinear dynamics of the heart. Cardiac optogenetics enables the manipulation of cellular function using light, enhancing our understanding of nonlinear cardiac function and control. Here, we investigate the efficacy of optically resonant feedback pacing (ORFP) to terminate ventricular tachyarrhythmias using numerical simulations and experiments in transgenic Langendorff-perfused mouse hearts. We show that ORFP outperforms the termination efficacy of the optical single-pulse (OSP) approach. When using ORFP, the total energy required for arrhythmia termination, i.e., the energy summed over all pulses in the sequence, is 1 mJ. With a success rate of 50%, the energy per pulse is 40 times lower than with OSP with a pulse duration of 10 ms. We demonstrate that even at light intensities below the excitation threshold, ORFP enables the termination of arrhythmias by spatiotemporal modulation of excitability inducing spiral wave drift.
A simple one-electron expression for electron rotational factors
Authors: Qiu Tian , Bhati Mansi , Tao Zhen , Bian Xuezhi , Rawlinson Jonathan , Littlejohn Robert G. , Subotnik Joseph E.
Published: March 2024

Within the context of fewest-switch surface hopping (FSSH) dynamics, one often wishes to remove the angular component of the derivative coupling between states J and K. In a previous set of papers, Shu et al. [J. Phys. Chem. Lett. 11, 1135–1140 (2020)] posited one approach for such a removal based on direct projection, while we isolated a second approach by constructing and differentiating a rotationally invariant basis. Unfortunately, neither approach was able to demonstrate a one-electron operatorÔ whose matrix element JÔK was the angular component of the derivative coupling. Here, we show that a one-electron operator can, in fact, be constructed efficiently in a semi-local fashion. The present results yield physical insight into designing new surface hopping algorithms and are of immediate use for FSSH calculations.
Numerical investigation of flow past a cylinder using cumulant lattice Boltzmann method
Authors: Xing Enbo , Liu Guangwei , Zhang Qinghe , Zhang Jinfeng , Ji Chaoqun
Published: March 2024

This paper presents simulations of flow past a circular cylinder within the subcritical Reynolds number (Re) range from 3900 to 2 × 105, utilizing the parameterized cumulant lattice Boltzmann model. In this study, a three-dimensional characteristic boundary condition for incompressible flow has been integrated into the lattice Boltzmann method at the outflow boundary to minimize spurious reflection. The flow field, wake statistics, hydrodynamic force, and power spectra results of Re = 3900 from the cumulant lattice Boltzmann model are exhaustively compared with the laboratory data and other numerical models. Relative to other numerical models employing turbulence closure, the cumulant lattice Boltzmann simulations demonstrate enhanced agreement with the experimental data even with relatively coarser grid resolution. The resolution-spanning feature for the cumulant lattice Boltzmann model in turbulent flows, without using explicit turbulence model, aligns with the previous benchmark case studies. The stability-preserving regularization process in the present model is analyzed. Results indicate that the influence of the regularization parameter is mitigated with improved grid resolution. A specific regularization parameter for flow around cylinder simulations is recommended. Variations in flow properties and hydrodynamic forces within the subcritical Reynolds number range of 3900 to 2 × 105 are analyzed. The results confirm that the parameterized cumulant lattice Boltzmann model can accurately simulate practical engineering flows, characterized by complex separation and recirculation, within the subcritical range. Moreover, the computational efficiency and parallel scalability are compared with other numerical methods.
Enhanced orbital torque efficiency in nonequilibrium Ru50Mo50(0001) alloy epitaxial thin films
Authors: Tang Ke , He Cong , Wen Zhenchao , Sukegawa Hiroaki , Ohkubo Tadakatsu , Nozaki Yukio , Mitani Seiji
Published: March 2024

Epitaxial thin films of fully nonequilibrium hcp-Ru50Mo50(0001) nanoalloys were prepared as a chemically disordered alloy, in which the intrinsic spin Hall effect is expected to be negligible. Structural analyses confirmed the epitaxial growth and atomic scale alloying of the films. In contrast to a tiny torque efficiency (ξDL) of ∼0.4% for Ru50Mo50/CoFeB, the ξDL for the Ru50Mo50/Ni heterostructure reached ∼30% with a long-range relaxation length. The apparent dependence of ξDL on the ferromagnetic layer can be attributed to the orbital Hall effect (OHE). Interestingly, a smaller ξDL was observed for Ru/Ni, suggesting that the nonequilibrium Ru50Mo50 enhances its OHE. Furthermore, the enhanced ξDL is maintained by inserting a Ru layer between the Ru50Mo50 and Ni layers, showing orbital transport through Ru. This finding illustrates potential applications of nonequilibrium nanoalloy films in spin orbitronics and contributes to getting insights into the understanding of the interrelationships between nanostructures and orbital transport properties.
Arbitrary multi-directional acoustic beam emission from a cylindrical metasurface with grafted topological charge
Authors: Cao Yue , Quan Jiaqi , Sun Baoyin , Fang Xicheng , Hang Zhihong , Gao Lei , Fu Yangyang , Xu Yadong
Published: March 2024

Directional sound beam emission from compact devices is highly desirable in many practical acoustic applications. Here, we present an approach for the efficient control of arbitrary multi-directional emission through a grafted metasurface that is designed by cutting and stitching two cylindrical phase-gradient metasurfaces carrying two opposite topological charges. The grafted metasurface provides a compact and robust platform for diverse multi-directional beam emission, whose beam number and azimuthal angles are precisely controlled by the topological charge. The underlying mechanism contributes to the wave interference of two opposite partial vortex waves. This scheme was verified by simulation and experimental results. Our work provides a design methodology for directional sound beam emission devices and may be useful for applications such as acoustic imaging, beam steering, and vortex detection.
Metasurface-based wireless communication technology and its applications
Authors: Cheng Xinyue , Li Chenxia , Fang Bo , Hong Zhi , Jin Yongxing , Jing Xufeng
Published: March 2024

Metasurfaces, due to their outstanding ability to control electromagnetic waves, have great application prospects in the field of wireless communication. This paper provides a comprehensive review of research work based on metasurface in three aspects: wireless power transfer, wireless information transmission, and novel wireless transceiver architectures. In the domain of wireless power transfer, several focusing metasurfaces and systems with unique performance are presented along with a new formula for calculating wireless power transfer. Concerning wireless information transmission section, the direct digital information transmission based on metasurface and the information transmission based on space-time-coding digital metasurface are introduced. Lastly, a simplified wireless transceiver with metasurfaces was introduced. The paper concludes with a discussion on the future directions of metasurfaces in the wireless communication domain.
Noise-independent route toward the genesis of a COMPACT ansatz for molecular energetics: A dynamic approach
Authors: Halder Dipanjali , Mondal Dibyendu , Maitra Rahul
Published: March 2024

Recent advances in quantum information and quantum science have inspired the development of various compact, dynamically structured ansätze that are expected to be realizable in Noisy Intermediate-Scale Quantum (NISQ) devices. However, such ansätze construction strategies hitherto developed involve considerable measurements, and thus, they deviate significantly in the NISQ platform from their ideal structures. Therefore, it is imperative that the usage of quantum resources be minimized while retaining the expressivity and dynamical structure of the ansatz that can adapt itself depending on the degree of correlation. We propose a novel ansatz construction strategy based on the ab initio many-body perturbation theory that requires no pre-circuit measurement and, thus, remains structurally unaffected by any hardware noise. The accuracy and quantum complexity associated with the ansatz are solely dictated by a pre-defined perturbative order, as desired, and, hence, are tunable. Furthermore, the underlying perturbative structure of the ansatz construction pipeline enables us to decompose any high-rank excitation that appears in higher perturbative orders into the product of various low-rank operators, and it thus keeps the execution gate-depth to its minimum. With a number of challenging applications on strongly correlated systems, we demonstrate that our ansatz performs significantly better, both in terms of accuracy, parameter count, and circuit depth, in comparison to the allied unitary coupled cluster based ansätze.
Two determinant distinguishable cluster
Authors: Schraivogel Thomas , Kats Daniel
Published: March 2024

A two reference determinant version of the distinguishable cluster with singles and doubles (DCSD) has been developed. We have implemented the two determinant distinguishable cluster (2D-DCSD) and the corresponding traditional 2D-CCSD method in a new open-source package written in Julia called ElemCo.jl. The methods were benchmarked on singlet and triplet excited states of valence and Rydberg character, as well as for singlet–triplet gaps of diradicals. It is demonstrated that the distinguishable cluster approximation improves the accuracy of 2D-CCSD.
Enhanced energy storage properties of silver niobate antiferroelectric ceramics with A-site Eu3+ substitution and their structural origin
Authors: Shi Peng , Liu Jin , Song Yuechan , Wu Wenwen , Liu Lina , Zhou Xiaobin , Chen Xiaoming , Lou Xiaojie , Liu Peng
Published: March 2024

AgNbO3 (AN)-based lead-free antiferroelectric ceramics are widely studied for their use as dielectric capacitor materials. In this study, Eu3+-doped AN ceramics were prepared and the results show that Eu3+ diffused into the AN lattice. The ceramics were formed by M1 and M2 phases coexisting at room temperature, as distinct from the M1 (M: monoclinic) phase of pure AN. Electrical properties and structural characterization showed that the antiferroelectric stability of the ceramics increases with the increase in Eu3+ levels. At room temperature, Ag0.94Eu0.02NbO3 ceramic exhibited a good energy storage density of 5.3 J/cm3 and a high efficiency of 71.9%. When the temperature rises from room temperature to 140 °C, the efficiency of the sample decreases from 80.4% to 67.1% and Wr decreases from 2.1 to 2.0 J/cm3, which indicates that the sample has good temperature stability. The time constant (t0.9) of this sample was less than 60 ns and the power density (PD) was 51.3 MW/cm3, indicating excellent charge–discharge capabilities. This novel ceramic is expected to be used as a new dielectric capacitor material for pulsed power supplies.
Impact dynamics of non-spherical droplets on a thin water film
Authors: Khan Talha , Jin Zheyan , Yang Zhigang
Published: March 2024

A droplet impinging on a liquid film finds numerous applications in diverse scientific fields. Although studies have primarily focused on spherical droplets, a droplet can present both spherical shape and non-spherical shape at the moment of impact. In the present study, the impact dynamics of a non-spherical droplet on a thin liquid film is investigated experimentally. The results show that, under the same film thickness and Weber number conditions, the splashing and deposition regimes are different for different droplet shapes such as prolate, sphere, and oblate. It is found that the splashing threshold (Ksp) is changed according to the shape of the droplet. Under the same condition when a spherical droplet is in the deposition mode, an oblate droplet is more likely to splash and form secondary droplets, while a prolate droplet is more splash-resistant even at higher Weber numbers. A modified theoretical model for crown radius evolution is developed. The predictions of theoretical model are found to agree well with the experimental results for spherical and non-spherical droplets. Moreover, at the same Weber number, a prolate droplet has a relatively higher maximum crown height than those of an oblate droplet and a spherical droplet.
Climate sustainability through a dynamic duo: Green hydrogen and crypto driving energy transition and decarbonization
Authors: Lal Apoorv , You Fengqi
Published: March 2024

Climate change persists as a pressing global issue due to high greenhouse gas emissions from fossil fuel–based energy sources. A transition to a greener energy matrix combined with carbon offsetting is imperative to mitigate the rate at which global temperature ascends. While countries have deployed faith in green hydrogen to accelerate worldwide decarbonization efforts, the concurrent rise of blockchain-operated crypto-applications, such as bitcoin, has exacerbated climate change concerns. In this study, we propose technological solutions that combine the green hydrogen infrastructure with bitcoin mining operations to catalyze environmental and socioeconomic sustainability in climate change mitigation strategies. Since the present state of crypto-operations undeniably contributes to worldwide carbon emissions, it becomes vital to explore opportunities for harnessing the widespread enthusiasm for bitcoin as an aid toward a sustainable and climate-friendly future. Our findings reveal that green hydrogen production, paired with crypto-operations, can accelerate the deployment of solar and wind power capacities to boost conventional mitigation frameworks. Specifically, leveraging the economic potential derived from green hydrogen and bitcoin for incremental investment in renewable energy penetration, this dynamic duo can enable capacity expansions of up to 25.5% and 73.2% for solar and wind power installations. Therefore, the proposed technological solutions that leverage green hydrogen and bitcoin mining, bolstered with appropriate policy interventions, can not only strengthen renewable power generation and carbon offsetting capacities but also contribute significantly to achieving climate sustainability.
Final report, ongoing key comparison BIPM.QM-K1, ozone at ambient level, comparison with EMPA, June 2023
Authors: Viallon Joële , Idrees Faraz , Moussay Philippe , Wielgosz Robert , Zellweger Christoph
Published: March 2024

Main text

As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone standard of the World Meteorological Organization maintained by the Swiss Federal Laboratories for Materials Science and Technology (EMPA) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount fraction range of 0 nmol mol−1 to 500 nmol mol−1.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Characteristics of the O(1S) to O(1D) 557.7 nm green emission observed in an argon plasma jet
Authors: Zhao Shuai , Wang Yanfei , Zhu Ximing , Sobota Ana
Published: March 2024

An extensive study on the green auroral emission characterization is presented based on a single dielectric barrier discharge geometry argon plasma jet driven by a kHz sine voltage. The plasma was generated by using 99.999% pure argon and the observed 557.7 nm green line resulted from the excited O(1S) state. An optical emission spectroscopy method using line ratios of argon was used to obtain the electron density and electron temperature under different conditions in the downstream region. The characteristics of discharge and green emission with variations in interelectrode distance, applied voltage (power) and flow rate are discussed. The spatially diffuse distribution of O(1S), owing to its long lifetime, is shown by the short exposure imaging. Two discharge regimes are presented, accompanied by two distinct branches of the green emission intensity, with a clear conclusion that the 557.7 nm emission is favored in the low electron temperature environment. In this work, the intense and diffuse green plume only forms when the downstream electron density is approximately lower than 1 × 1014 cm−3 and the electron temperature is lower than 1.1 eV. By charging the two electrodes in two opposite ways, it is shown that the green emission from oxygen is favored in the case where the electric field and the electron drift are not continuous.
Profiles of oxygen and titanium point defects in ferromagnetic TiO2 films
Authors: Quynh Nhu Tran , Friák Martin , Miháliková Ivana , Kiaba Michal , Hoa Hong Nguyen
Published: March 2024

Experimentally it is shown that without any oxygen manipulation for TiO2, a strong room temperature ferromagnetism could be expected only in ultra-thin films, with the ideal thickness below 100 nm. Both bulks and nano-powders of TiO2 are diamagnetic, indicating that the surface and its nano-sublayers play very important roles in tailoring the magnetic properties in this type of compound. To shed a new light on the defect-related magnetism in the typical case of anatase TiO2 surfaces, we have performed a series of quantum-mechanical calculations for TiO2 slabs containing Ti or O vacancies in different distances from the (001) surface. The lowest formation energies were obtained for the Ti vacancies in the first sub-surface layer and the O vacancies within the surface. The computed magnetic states reflect complicated structural relaxations of atoms influenced by both the surface and vacant atomic positions. O atoms cannot contribute much to magnetic moment when Ti vacancies are isolated and far from the surface. Ti vacancies in TiO2 are only metastable. The formation energy of Ti interstitials is lower than for Ti vacancies since high-temperature annealing, especially with a lot of O2 available that would fill up O-related defects, and as a result, eliminate most of Ti vacancies. Lower temperatures, less O2, and shorter exposure times may enable not only partial elimination of Ti vacancies but also can facilitate their diffusion into different states of aggregations. In the ferromagnetic films (i.e. thin films below 100 nm), it looks like that the O atoms are located closer to the Ti vacancies.
Investigation of coherent Fourier scatterometry as a calibration tool for determination of steep side wall angle and height of a nanostructure
Authors: Paul Anubhav , Rafighdoost Jila , Dou Xiujie , Pereira Silvania F
Published: March 2024

Nanostructures with steep side wall angles

(

swa

)

play a pivotal role in various technological applications. Accurate characterization of these nanostructures is crucial for optimizing their performance. In this study, we propose a far-field detection method based on coherent Fourier scatterometry (CFS) for accurate quantification of steep

swa

and heights in cliff-like nanostructures. Our approach introduces a parameter termed ‘visibility’, derived from the unique far-field signatures of cliff-like nanostructures. This parameter serves as a quantitative metric for the calibration of

swa

and heights. The heightened sensitivity of our method is demonstrated, particularly when the incident polarization is perpendicular to the invariant direction of the nanostructure for

swa

calibration, while both polarization states exhibit sensitivity to height calibration. Furthermore, a comprehensive sensitivity analysis reveals the stable nature of our method, showcasing that even with fluctuations of ±10 nm in the position of the nanostructure, the resulting

swa

remains stable within a range of

±

0.5
∘

. The exponential variation of the visibility parameter with edge roundness is observed, with fluctuations in edge roundness within 10 nm resulting in

swa

variations within 1.7∘ for both polarization states. In experimental validations, our results demonstrate reasonable agreement between CFS-derived and AFM measurements. The AFM data for swa (

77.99
∘

±

1.37
∘

) and height (148.35 nm ±2.11 nm) are corroborated with CFS-derived value of

swa

(

77.75
∘

±

3.61
∘

,

78.36
∘

±

3.89
∘

) and height (149.42 nm ±1.66 nm, 150.05 nm ±1.04 nm) obtained from calibration curves for TM and TE incident beams, respectively. Overall, our findings underscore CFS as a potential and reliable tool for nanostructure characterization, offering precise measurements that are pivotal for advancing nanotechnology.
Composition and optical properties of (In, Ga)As nanowires grown by group-III-assisted molecular beam epitaxy
Authors: Ruiz M Gómez , Castro A , Herranz J , da Silva A , John P , Trampert A , Brandt O , Geelhaar L , Lähnemann J
Published: March 2024

(In, Ga) alloy droplets are used to catalyse the growth of (In, Ga)As nanowires by molecular beam epitaxy on Si(111) substrates. The composition, morphology and optical properties of these nanowires can be tuned by the employed elemental fluxes. To incorporate more than 10% of In, a high In/(In+Ga) flux ratio above 0.7 is required. We report a maximum In content of almost 30% in bulk (In, Ga)As nanowires for an In/(In+Ga) flux ratio of 0.8. However, with increasing In/(In+Ga) flux ratio, the nanowire length and diameter are notably reduced. Using photoluminescence and cathodoluminescence spectroscopy on nanowires covered by a passivating (In, Al)As shell, two luminescence bands are observed. A significant segment of the nanowires shows homogeneous emission, with a wavelength corresponding to the In content in this segment, while the consumption of the catalyst droplet leads to a spectrally-shifted emission band at the top of the nanowires. The (In,Ga)As nanowires studied in this work provide a new approach for the integration of infrared emitters on Si platforms.
Exploring the weak visible-near-infrared and NO2 detection capabilities of PbS/Sb2O5 heterostructures with DFT interpretations
Authors: Kumar Utkarsh , Tsou Yu-Che , Deng Zu-Yin , Yadav B C , Huang Wen-Min , Wu Chiu-Hsien
Published: March 2024

The need for photosensors and gas sensors arises from their pivotal roles in various technological applications, ensuring enhanced efficiency, safety, and functionality in diverse fields. In this paper, interlinked PbS/Sb2O5 thin film has been synthesized by a magnetron sputtering method. We control the temperature to form the nanocomposite by using their different nucleation temperature during the sulfonation process. A nanostructured PbS/Sb2O5 with cross-linked morphology was synthesized by using this fast and efficient method. This method has also been used to grow a uniform thin film of nanocomposite. The photo-sensing and gas-sensing properties related to the PbS/Sb2O5 compared with those of other nanomaterials have also been investigated. The experimental and theoretical calculations reveal that the PbS/Sb2O5 exhibits extraordinarily superior photo-sensing and gas-sensing properties in terms of providing a pathway for electron transport to the electrode. The attractive highly sensitive photo and gas sensing properties of PbS/Sb2O5 make them applicable for many different kinds of applications. The responsivity and detectivity of PbS/Sb2O5 are 0.28 S/mWcm−2 and 1.68 × 1011 Jones respectively. The sensor response towards NO2 gas was found to be 0.98 at 10 ppb with an limit of detection (LOD) of 0.083 ppb. The PbS/Sb2O5 exhibits high selectivity towards the NO2 gas. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were used to analyze the geometries, electronic structure, and electronic absorption spectra of a light sensor fabricated by PbS/Sb2O5. The results are very analogous to the experimental results. Both photosensors and gas sensors are indispensable tools that contribute significantly to the evolution of technology and the improvement of various aspects of modern life.
Self-sensing model of low-frequency magnetostrictive composites actuator based on Jiles-Atherton theory
Authors: Chen Jiamin , Wang Lei , Yu Jiuwei , Sun Hongwei , Wang Jing , Zhang Haoze
Published: March 2024

Giant magnetostrictive powder composites (GMPCs) have important applications in electric current sensing, stress sensing, vibration damping, actuation, health monitoring and other fields. Most of the research discussed the actuation or sensing function of GMPCs merely. In this paper, GMPCs based actuator with a self-sensing function is proposed to realize direct measurement of the deformation amplitudes of the actuator in low frequency, through monitoring the voltage signal of the driving circuit. It also means the actuator can be used as a compressive stress and magnetostriction sensor. The self-sensing actuator avoids the dependence on extra sensors for actuation detection, which complements the self-sensing technique in GMPC-based actuators. It is helpful not only in the designing and controlling of self-sensing applications in actuators, but also in expanding the applications of GMPCs in the field of integrated devices.
Analytical study of linear optical properties of metal nanoparticle trimers: the impact of dipole-dipole interaction on different modes of configuration
Authors: Farhoomand Afsoon , Sepehri Javan Nasser , Kheirandish Asef
Published: March 2024

In this study, we theoretically investigate the linear properties of a metal nanoparticle (MNP) trimer. Three identical spherical nanoparticles (NPs) whose centers are equidistantly oriented on a same straight line are considered. Using the solid core approximation for NPs and considering interaction between particles through induced electric dipoles, the motion equation of each NP conduction electrons is analytically solved. Some appropriately approximated expressions are derived for the permittivity of each NP based on a Drude-like model, allowing the clear observation of the contribution of inter-particle interaction. Depending on the orientation of the trimer axis and incident laser beam geometry (i.e., orientation of electromagnetic (EM) fields and wave vector of laser beam), three different configurations or modes are considered. The extinction efficiency of each NP as a function of wavelength is plotted, revealing that when the laser electric field is perpendicular to the symmetry axis of the trimer, it increases compared to the case of non-interactional single NP, and its plasmon resonance peak experiences a red shift. For other cases where the electric field of the laser beam is parallel to the trimer axis, the extinction efficiency of each NP decreases, and its peak shifts to the blue. In all cases, the effect of interaction on the optical properties of the middle NP is greater than on the other NPs.
Ultra-high harmonic conversion of a seeded free-electron laser via harmonic optical klystron
Authors: Wang Xiaofan , Zeng Li , Zhang Weiqing , Yang Xueming
Published: March 2024

External seeded free-electron lasers (FELs) are compelling tools for generating fully coherent EUV and soft x-ray radiations. Echo-enabled harmonic generation (EEHG), the most typical representative of external seeded FELs, has witnessed a remarkable growth of fully coherent FELs in the last decade, continuously evolving towards higher harmonic conversions and shorter wavelengths. Ultra-high harmonic generation is imperative in the field of FELs. This paper presents a novel method for generating FEL radiation with ultra-high harmonic conversion, utilizing harmonic optical klystron in combination with EEHG. This method can effectively increase the harmonic conversion order to about 90. Theoretical analysis and numerical simulations show that intense and almost fully coherent FEL pulses can be generated with a wavelength of 3 nm. At the same time, the seed laser intensity required by this scheme is lower compared to nominal EEHG, thus facilitating the generation of high-repetition-rate seeded FELs.
Coating effects of a strain sensor on durability and sensitivity using the fiber loop ringdown spectroscopy technique
Authors: Kaya Burak Malik , Esenturk Okan , Asici Celal , Sarac Umut , Dindis Gokhan , Baykul Mevlana Celalettin
Published: March 2024

A sensor region in a single-mode optical fiber loop was created and utilized in order to study the coating effect on sensor durability and system sensitivity by the Fiber Loop Ringdown Spectroscopy (FLRDS) technique. The sensor system was simply designed without any additional optical components. The bending loss theory in the single-mode fiber (SMF) was taken into account in data calculation. After stretching was performed on 10.0 cm long coated and noncoated sensorheads from the mid-points, the strain detection limits were determined as 5.3345 με and 6.7497 με with bare and coated sensorheads, respectively. The purpose of this study is to analyze the effect of N,N-Diethyl-p-phenylenediamine (NDPD) coating of the sensorhead on the sensor durability and sensitivity. The baseline stability of the system was obtained as 1.18% by considering a hundred consecutive data. Regarding to obtained results, the difference between calculated total optical losses of FLRDS systems with noncoated and NDPD coated sensorheads shows that coating sensorhead enhanced the sensor durability and the system sensitivity. An FLRDS system with high sensitivity, simple design and easy setup offers real-time measurement with continuous monitoring and provides advantages on durability by modification the sensorhead such as NDPD coating. Due to its attractive features such as low cost, simplicity, easy setup, high sensitivity, increased durability and continuous monitoring, an FLRDS system has a wide range of application areas in structural health monitoring, transportation, early detection, biomedical, chemical trace elements, rail and asphalt applications for continuous monitoring in a real-time merit.
Study on transfer learning-based cross-spectral speckle image reconstruction method
Authors: Zhao He , Zhang Yanzhu , Wu Hao , Pu Jixiong
Published: March 2024

In recent years, convolutional neural networks (CNNs) have been successfully applied to reconstruct images from speckle patterns generated as objects pass through scattering media. To achieve this objective, a large amount of data is collected for training the CNN. However, in certain cases, the characteristics of light passing through the scattering medium may vary. In such situations, it is necessary to collect a substantial amount of new data to re-train the CNN and achieve image reconstruction. To address this challenge, transfer learning techniques are introduced in this study. Specifically, we propose a novel Residual U-Net Generative Adversarial Network, denoted as ResU-GAN. The network is initially pre-trained using a large amount of data collected from either visible or non-visible light sources, and subsequently fine-tuned using a small amount of data collected from non-visible or visible light sources. Experimental results demonstrate the outstanding reconstruction performance of the ResU-GAN network. Furthermore, by combining transfer learning techniques, the network enables the reconstruction of speckle images across different datasets. The findings presented in this paper provide a more generalized approach for utilizing CNNs in cross-spectral speckle imaging.
On comparative analysis of graph entropies of symmetrical carbon nanotube Y-junctions
Authors: Al-Dayel Ibrahim , Nadeem Muhammad Faisal , Khan Meraj Ali
Published: March 2024

Entropy is crucial in statistical mechanics, thermodynamics, and information theory as it measures a system’s level of randomness or disorder. Entropy is widely used in mathematical chemistry and computational physics to predict the behavior of a system under various conditions. Among numerous carbon nanotube structures, three-terminal carbon nanotube junctions are important structures not only for electrical but also for mechanical appliances. Recently, significant attention has been given to the understanding of carbon nanotube junctions. This research paper focuses on calculating graph entropies based on Zagreb indices for symmetrical single-walled armchair carbon nanotube Y − junctions and comparing the index-entropies of these junctions. The study aims to demonstrate the behavior of the nanotube Y − junctions by adding atoms at the end of the tubes.
Wormhole solutions under the effect of dark matter in f(R, Lm) gravity
Authors: Jaybhaye Lakhan V , Tayde Moreshwar , Sahoo P K
Published: March 2024

In the background off(R,Lm) gravity, this work investigates three distinct dark matter halo profiles to test the possibility of generalised wormhole geometry within the galactic halo regions. The current study aims to accomplish these goals by examining various dark matter profiles including universal rotation curves (URC), Navarro–Frenk–White (NFW) model-I, and NFW model-II inside two distinctf(R,Lm) gravity models. According to thef(R,Lm)=R2+Lmαmodel, the dark matter (DM) halo density profiles produce suitable shape functions that meet all the necessary requirements for exhibiting the wormhole geometries with appropriate choice of free parameters. In addition, to examine DM profiles under thef(R,Lm)=R2+(1+λR)Lmmodel, we consider a specific shape function. Further, we observed that the derived solution from both two models violates the null energy constraints, confirming that the DM supports wormholes to maintain in the galactic halo.
Phase-modulated single-photon router and chiral scattering between two waveguides coupled by a giant three-level atom
Authors: Zhou J X , Zhu Z H , Zhang Y Q , Chen K K , Peng Z H , Chai Y F , Xiong Z Z , Tan L
Published: March 2024

We investigate a T-shaped single-photon router constructed by two waveguides connected via a giant Λ-type three-level atom. Under a real-space approach, the analytical expressions of the single-photon transmission and reflection amplitudes are obtained. It is shown that a high transfer-rate routing between two waveguides can be effectively achieved by modulating the phase difference, the accumulated phase and the atom-waveguide coupling strengths, and its frequencies can be tuned with a classical driving field. Interestingly, chiral scattering and a single-photon targeted router with direction selectivity have been realized by the ideally equivalent atom-waveguide interaction. We believe that our results have potential applications in constructing optical quantum devices and designing the single-photon quantum routing using the giant-atom setup.
1.3 μm InAs/GaAs quantum-dot lasers grown on planar on-axis Si (001) substrates with high slope-efficiency and low differential resistance
Authors: Lin Feng , Wang Jun , Zhai Hao , Liu Shuaicheng , Ge Qing , Chen Yanan , Liu Chuanjiang , Mao Kaize , Liu Hao , Bai Yiming , Wang Qi , Huang Yongqing , Ren Xiaomin
Published: March 2024

We report electrically pumped continuous-wave (CW) InAs/GaAs quantum dot lasers monolithically grown on planar on-axis Si (001) substrates. Combining an asymmetric waveguide epitaxy structure with aluminium-free upper cladding layers and a symmetrical cathode chip structure, 1.3 μm band lasers with low differential resistance and high slope-efficiency have been achieved. Moreover, the optimized symmetrical cathode structure of the laser chips is used to improve the slope-efficiency by reducing the differential resistance and waste heat. The Fabry–Perot broad-stripe edge-emitting lasers with 2000 μm cavity length and 15 μm stripe width achieve a single-facet output power of 73 mW, a single-facet slope efficiency of 0.165 W A−1, and a differential resistance of 1.31 Ω at ∼1.31 μm wavelength under CW conditions at room temperature (25 °C). Importantly, these results provide an effective strategy to achieve 1.3 μm wavelength band single-mode distributed feedback lasers directly on planar on-axis Si (001) substrates with high efficiency.
Substantial increase in population exposure to multiple environmental burdens in sub-Saharan Africa (2000-2019)
Authors: Sikarwar Ankit , Golaz Valérie
Published: March 2024

In the face of increasing global environmental uncertainties, sub-Saharan Africa stands as a highly vulnerable region with a massive population marked with poverty and inequalities. Moreover, different environmental risk factors can coexist simultaneously as multiple environmental burdens (MEBs); however, population exposure to MEB remains unexamined. Here, using open-access spatial data and critical thresholds, we quantify population exposure to four key environmental risk factors: hazardous fine particulate matter (PM2.5) levels, extreme temperature increase, prolonged severe droughts, and green deficit (scarcity of green trees). Further, we explore the concept of MEB, where these risk factors converge. We derive exposure for 2000 and 2019 at the pixel (1 km grid cell) level. We also check how population change, environmental change, and their interaction contribute to the total change in exposure. We found substantial changes in the population exposed from 2000 to 2019, i.e. an increase of ∼460 million people to hazardous PM2.5 levels, ∼16 million to extreme temperature increase, ∼13 million to prolonged severe droughts, and ∼246 million to green deficit. Population exposure to at least three of these four environmental risk factors (3EB) has increased by ∼246 million. In this increase in exposure to 3EB, the contribution of environmental change is higher (48%), than that of interaction and population change (36% and 15%, respectively). Notably, there are striking disparities in population exposure, its change, and the contributing effects among countries and regions of sub-Saharan Africa.
Detecting the impact of climate change on tropical cyclones in Southern China
Authors: Tu Shifei , Zhang Yifan , Liang Mei , Wu Deping , Xu Jianjun
Published: March 2024

It is well known that tropical cyclones (TCs) making landfall in Southern China (SC) account for more than half of all TCs making landfall in China. Therefore, it is important to have an in-depth understanding of the activities of TCs in SC under climate warming. Our results show that there have been no significant changes in the frequency and duration of these TCs, but their intensities have unexpectedly decreased by ∼20% since 1980, which is inconsistent with the previous understanding that climate change increases TC intensity. The results consistently show a significant decrease in the different TC intensity percentiles, which is related to the intensity distribution that shows a significant decrease in the proportion of tropical storms and a significant increase in the proportion of tropical depressions, as well as a slight decrease in the proportion of category 1–2. Because of the locations of those TCs activity show a clear shoreward migration tendency, indicating that land friction can suppress TC intensification, so that TC intensity has weakened. In addition, results also suggest that TC development is strongly suppressed and is mainly related to the enhancement of atmospheric stability, vertical wind shear and subtropical high under global warming. These results are quite different from the previous understanding of the changes in TC intensity under global warming. Such knowledge can help us better understand the relationship between climate change and the impact of TC activity at the regional scale.
Helping the climate by replacing liquefied natural gas with liquefied hydrogen or ammonia?
Authors: Wolfram Paul , O’Rourke Patrick , McJeon Haewon , Kyle Page
Published: March 2024

The war in Ukraine caused Europe to more than double its imports of liquefied natural gas (LNG) in only one year. In addition, imported LNG remains a crucial source of energy for resource-poor countries, such as Japan, where LNG imports satisfy about a quarter of the country’s primary energy demand. However, an increasing number of countries are formulating stringent decarbonization plans. Liquefied hydrogen and liquefied ammonia coupled with carbon capture and storage (LH2-CCS, LNH3-CCS) are emerging as the front runners in the search for low-carbon alternatives to LNG. Yet, little is currently known about the full environmental profile of LH2-CCS and LNH3-CCS because several characteristics of the two alternatives have only been analyzed in isolation in previous work. Here we show that the potential of these fuels to reduce greenhouse gas (GHG) emissions throughout the supply chain is highly uncertain. Our best estimate is that LH2-CCS and LNH3-CCS can reduce GHG emissions by 25%–61% relative to LNG assuming a 100 year global warming potential. However, directly coupling LNG with CCS would lead to substantial GHG reductions on the order of 74%. Further, under certain conditions, emissions from LH2-CCS and LNH3-CCS could exceed those of LNG, by up to 44%. These results question the suitability of LH2-CCS and LNH3-CCS for stringent decarbonization purposes.