bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein-based microlasers: continuous transition from whispering gallery mode to random lasing
Authors: Nguyen Tam Trong , Mai Hanh Hong , Do Tien Xuan , Giang Khoi Manh , Nguyen Toan Van , Nguyen Tien Van , Nguyen Thau Xuan , Le Tuan Duy , Le Hai Hoang , Ta Van Duong 
Published: January 2025

Abstract
Whispering gallery mode (WGM) and random biolasers are important for bio-integration and biosensing applications due to their biocompatibility. However, these two laser types typically require different fabrication techniques, and limited research has explored transitioning between them using the same fabrication process. In this work, we present a comprehensive investigation into the transition from WGM to random lasing in protein-based microsphere lasers. Through a dehydration method, we can fabricate dye-doped protein microspheres with diameters ranging from 20 to 150 µm. By varying the polystyrene (PS) particle concentration within these microspheres, we observed a continuous transition from WGM to random lasing under optical pumping, driven by enhanced light scattering as PS concentration increased. Key lasing parameters, including the lasing spectrum and lasing threshold versus laser size and PS concentration, were analyzed and compared. The results indicate that microsphere random lasers (RLs) exhibit shorter lasing wavelengths. Particularly, a 63 µm WGM laser has a central lasing wavelength at 630 nm, while a RL of similar size shows a peak wavelength at 590 nm, a 40 nm blue shift. The lasing threshold increases with smaller laser size and higher PS concentration, with WGM lasers requiring several µJ mm−2, potentially ten times lower than RLs. Our work opens the possibility of designing flexible, wavelength-tunable biological microlasers. Moreover, it provides an understanding of the distinct characteristics of WGM and random lasing, making a meaningful contribution to laser research.
High Q-factor mie lattice resonance generated from out-of-plane magnetic dipole in all-dielectric defected semi-cylinder metasurface array
Authors: Zhang Lei , Liang Kunlin , Sun Chengchen , Tu Shijuan , Fu Qin , Feng Shuai , Du Qingguo , Li Zhengying , Xu Fei 
Published: January 2025

Abstract
Due to the weak far-field radiation and strong local field enhancement properties of Mie lattice resonances(MLRs), a transmission resonance with a significantly high Q factor is achieved, which can be used in applications such as refractive index sensing, filtering, and nanolasing. In this paper, we design a semi-cylinder with a cuboid defect metasurface array working in the near-infrared, where a resonance with extremely narrow linewidth in transmission spectrum has been demonstrated at the wavelength of 870.9408 nm. The full width at half-maximum of the resonance is as narrow as 0.0032 nm with a corresponding Q factor of 272169. According to distributions of the electric field and displacement current, it is confirmed that the narrow linewidth resonance is generated by the MLR, which originates from the coupling between the out-of-plane magnetic dipole mode and Rayleigh Anomalous diffraction. It is further verified that the out-of-plane magnetic dipole mode is excited due to the induce defect in the semi-cylinder. When applied to refractive index sensing, a sensitivity of 333 nm RIU‒1 and a figure of merit of 104063

RIU

−
1

are numerically achieved simultaneously. Our study here provides a new approach for achieving resonances with high Q-factors for the required applications.
Experimental and theoretical advances in Cu2ZnSn(S,Se)4 solar cells
Authors: Rodriguez-Osorio K G , Andrade-Arvizu J A , Montoya De Los Santos I , Morán-Lázaro J P , Ojeda-Martinez M , Sánchez-Rodríguez F J , Sánchez-Hernández L A , Pérez L M , Laroze D , Chandrasekar P , Routray S , Courel Maykel 
Published: January 2025

Abstract
Cu2ZnSn(SSe)4 (CZTSSe) semiconductor is quite promising to solar cell applications, recently achieving a new record efficiency of 14.9%. Despite theoretical works have shown that efficiencies higher than 20% are possible in this technology, there are some critical points that should be carefully solved by the scientific community. In this review, it is presented a critical analysis on the state-of-the-art of Cu2ZnSn(SSe)4 solar cells. First, we summarize advantages and disadvantages of most used vacuum and non-vacuum thin film fabrication methods, followed by the most important results in solar cell fabrication along with key factors in performance improvement. Furthermore, the future experimental outlook is also analyzed with a particular focus on kesterite material engineering and its grading band-gap engineering. Likewise, the experimental state-of-the-art of CZTSSe device fabrication, a non-typical contribution of this work to the literature it is the presentation and discussion of most important theoretical results on solar cells. A particular attention is paid to results concerning numerical and analytical approaches for the study of Cu2ZnSn(SSe)4 solar cells. Finally, theoretical results concerning the potential use of nanostructured CZTSSe solar cells for achieving efficiencies higher than that of the Shockley–Queisser limit are presented and discussed.
Spherical tip-plasma resonance probe with an improved upper pressure limit for electron density measurements in low-density plasmas
Authors: Lee SangHo , Kim SiJun , Park InYong , Eom GeonWoong , Seo Byonghoon , Hur Min , Kang WooSeok , You ShinJae , Kim Dae-Woong 
Published: January 2025

Abstract
Plasma resonance probes (PRPs) are used for electron density measurements based on the observation of the plasma resonance (PR) negative peak frequency at the electron plasma frequency in the transmission microwave spectrum. The cylindrical tip-plasma resonance probe (CT-PRP), also known as the cutoff probe, is widely used due to its simple structure. A recent study indicated that increasing the sheath width around the CT-PRP tip resulted in the PR negative peak frequency deviating from the electron plasma frequency and acted as a source of lowering the upper operating pressure limit. This disturbance becomes significant in low-density plasmas (

<

10

10

c

m

−
3

)

, where thicker sheaths are unavoidable. This study proposes a spherical tip-plasma resonance probe (ST-PRP) to reduce the sheath width effect via the use of a lower sheath impedance of its spherical tip structure. The improved upper operating pressure limit of the ST-PRP was investigated using a three-dimensional electromagnetic simulation model. The results showed that the ST-PRP extended the upper limit of operating pressure and reduced the sensitivity of the upper pressure limit for changes in sheath width greater than the CT-PRP. An experimental study in low electron density capacitively coupled plasma sources was conducted to compare the upper pressure limit between the ST-PRP and the CT-PRP. The results were consistent with the numerical simulation results. We believe that the proposed ST-PRP with an extended upper pressure limit can be a reliable tool for accurate plasma electron density measurements of low-density plasmas using PRPs.
PIC/Fluid simulations of the plasma expansion in a planar magnetic arch
Authors: Guaita M , Ahedo E , Merino M 
Published: January 2025

Abstract
Magnetic arches (MA) (i.e. the magnetic topology that emerges when placing two magnetic nozzles with opposite polarities side by side) are an attractive option for the clustering of multiple electrodeless plasma thrusters, as they are characterized by a zero magnetic dipole moment and thus allow a reduction of perturbing magnetic forces on the spacecraft. This work employs the hybrid code EP2PLUS to simulate and study the plasma expansion for such a magnetic topology in the planar limit. First, a reference simulation is used to analyze the leading physical mechanisms that govern the plume properties. Ions are thus found to be characterized by a double peaked velocity distribution function close to the symmetry plane, where the plasma beams emitted by the two thrusters merge, while the magnetic force acting on electrons is shown to shape both the lateral confinement of the plume, and the thrust profile provided. Second, a parametric sweep on the strength of the magnetic field shows that its influence on the propulsive properties and on the characteristics of the plume saturates for values of the Hall parameter larger than around 10. Beyond this value of the Hall parameter, only the in-plane electron currents are found to be particularly sensitive both to the magnetization levels and the boundary conditions employed, although they are also largely decoupled from the rest of plasma properties. Finally, background pressure effects were considered by including collisions with neutral atoms in the simulations, highlighting the relevance of neutral entrainment in the modification of the plume properties and in the propulsive performance of the MA.
Metal–semiconductor–metal photodiode fabricated with an AlGaN/AlN superlattice for UV light detection
Authors: Wang Tong-Wen , Sharma Mukta , Tsai Chia-Lung , Zhang Jin-Rong 
Published: January 2025

Abstract
We designed and fabricated a nonplanar metal–semiconductor–metal (MSM) ultraviolet photodetector (PD), incorporating a 30-pair Al0.5Ga0.5N/AlN superlattice (SL) absorption layer on GaN-on-sapphire templates. In contrast to conventional PDs featuring a 100 nm-thick Al0.25Ga0.75N epilayer, our proposed PDs with the higher Al content of Al0.5Ga0.5N/AlN SLs did not exhibit degradation in epiwafer quality. With the incorporation of Al0.5Ga0.5N/AlN SLs, proposed MSM PDs with a top Ti/Al-based metal stack and a bottom Ni/Au electrode configuration showcased an enhanced photoresponsivity of 1129.8 A W−1 at ‒5 V in comparison to unitary Al0.25Ga0.75N epilayer made PDs. Moreover, by utilizing the Al0.5Ga0.5N/AlN SL absorption layer, we achieved an increased light-to-dark current ratio, reaching 3.66 × 105 biasing at a ‒7 V. The improvement in PD’s output performance could be attributed to the low metal/semiconductor Schottky barrier and strong electric field intensity within the SL absorption layer as the Ti/Al-based metal stack was used as the top electrode (the bottom electrode is Ni/Au). Finally, a 3 dB cut-off frequency of ∼1.2 MHz is achieved by using a homemade LED-based optical link with the proposed MSM PDs as the optical receiver.
Indium doping effects on the structural, morphological and electrical properties of WO3 powder pellets
Authors: Khusayfan Najla M , Khanfar Hazem K , Alharbi Seham R 
Published: January 2025

Abstract
Tungsten oxide powders were doped with indium at weight percentages ranging from 5 to 15 wt% and pressed into pellet form under a pressure of 200 bars. The doping process was carried out using the solid-state reaction technique. The doped samples were sintered at 750 °C for 12 h. Both undoped and indium-doped powder pellets exhibited a triclinic structure, with hexagonal InxWO3 emerging as a minor phase that increased with higher indium content. Indium doping increased microstrain, the percentage of stacking faults, and defect concentration while decreasing the crystallite sizes in the WO3 powder pellets. Morphological analysis of the samples revealed irregular grain shapes and sizes within the pellets. Notably, indium doping significantly reduced the porosity of WO3 from 7.42% to 3.83% as the indium content increased to 15 wt%. Electrically, the n-type resistivity increased with higher doping levels, indicating deeper donor levels. Specifically, the donor states in the powder pellets increased from 0.21 eV to 0.27 eV as the indium content rose from 5 wt% to 10 wt%, and further reached 0.29 eV at 15 wt% indium. Moreover, AC signal analysis of the powder pellets demonstrated their potential as microwave resonators suitable for antenna applications. Indium doping effectively engineered the maximum cutoff frequency, with values reaching 80 GHz in WO3 pellets doped with 15 wt% indium. These powder pellets, with thicknesses not exceeding 700 μm and electrode areas of 3.14 × 10−2 cm2, show great promise for 5 G/6 G technology applications as concurrent quad-band antennas.
Modeling and simulation of the effect of surface roughness on the Fowler-Nordheim conduction in MOS structures
Authors: Meguellati S , Messai Z , Sarra M 
Published: January 2025

Abstract
A compact Fowler–Nordheim (FN) tunneling current model is derived to describe the non-ideal, surface roughness-related relationship between current and voltage in a metal-oxide-semiconductor (MOS) capacitors. This relationship is achieved by applying a fractal continuum Laplacian operator in the 1D Schrödinger equation, resulting in a model that extends the standard FN to account for surface inhomogeneities through a fractional power α. Our error analysis predicts significant inaccuracies in the extracted FN parameters when using the standard FN model to interpret rough surface data. A methodology for extracting FN fractal parameters and the flat band voltage via a fractal FN plot is proposed. Simulated datasets and real measurements of Al/SiO2/4H-SiC capacitors are used to validate the model. Comparison of the parameters extracted using the fractal FN model and the standard FN model confirms the predictions from the error analysis and the suitability of the fractal FN model. The fractal FN model offers a potential explanation for the large discrepancies observed in FN parameters reported in the literature.
Electron and positron impact ionization cross sections of SiF4
Authors: Song Yunliang , Ma Yuwei , Li Bowen , Chen Ximeng 
Published: January 2025

Abstract
Based on the Binary-Encounter-Bethe (BEB) model, we present comprehensive cross-sectional data on total ionization cross sections, partial cross sections, single differential cross sections, average secondary electron energy and stopping cross sections for the SiF4 molecule in the case of electron and positron impact. For the partial cross sections, we employ the mass spectrum data (MSD) method and Huber’s model. By comparing theoretical calculations with experimental measurements, we determine the fragmentation pattern of SiF4. For positron scattering, we utilize three methods known as BEB0, BEBA, and BEBW. There is limited data of electron impact available on SiF4, and there is a notable lack of relevant investigations regarding positron impact with SiF4. Our research continues the exploration of electron and positron impact cross sections for SiF4 and serves as a reference for future studies.
Exploring the impact of substituents on the photophysical properties of boron dipyrromethene dyes for enhanced photovoltaic performance
Authors: Cui Peng , Ling Zichao 
Published: January 2025

Abstract
Boron dipyrromethene (BODIPY) dyes are known for their strong fluorescence and excellent photostability, making them vital for various photoelectric applications. This study explores how different substituents affect the photophysical properties of BODIPY dyes to improve their performance in dye-sensitized solar cells (DSSCs). We examine six distinct BODIPY dye structures with unique electron-withdrawing (NO2, CHO, Br) and electron-donating (OCH3, NPh2) substituents, along with a hydrogen-substituted variant, and report key photovoltaic parameters, including open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and energy conversion efficiency (Ω). Using density functional theory (DFT) and time-dependent DFT (TD-DFT), we analyze the dyes’ light-harvesting efficiency, electron injection efficiency, and overall energy conversion efficiency. Our results indicate that electron-donating groups, especially NPh2 and OCH3, significantly enhance Voc, Jsc, FF, and Ω, leading to improved energy conversion efficiencies. In contrast, while electron-withdrawing substituents increase chemical stability, they typically result in lower photovoltaic performance. This research underscores the importance of strategic substituent selection in optimizing BODIPY dyes for enhanced photoelectric performance, offering valuable insights for designing efficient photovoltaic materials.
Investigation on flux design & their effect on the mechanical properties of the SAW of Duplex Stainless Steel-2205
Authors: Gupta Deepak , Bansal Amit , Jindal Sandeep 
Published: January 2025

Abstract
The SAW fluxes for Duplex Stainless Steel (DSS)-2205 are not easily available. Generally, the available flux configuration is suitable for different grades of stainless steel but not suitable for the DSS. The current research aims to formulate the flux for DSS-2205 by varying the different flux ingredients and to investigate the impact of linear flux ingredients and their binary mixture effect on the mechanical characteristics of the butt joining of DSS-2205. The technique of extreme vertices design suggested by McLean and Anderson is employed to develop twenty-one fluxes. The effect of twenty-one flux ingredients was analyzed on the fabricated weldment’s characteristics such as ultimate tensile strength (UTS), percentage elongation, impact strength, and microhardness. In this research, a mathematical model has been developed for UTS, percentage elongation, impact strength and microhardness of weld specimens in terms of the flux ingredients. It is found from the experiments that the tensile strength and percentage elongation of weldments is increased by the flux ingredients such as silica (SiO2) and magnesium-oxide (MgO), while the alumina (Al2O3) and calcium fluoride (CaF2) has decreasing effect on UTS. Impact strength is found to be decreased by the linear effect of Al2O3. Excluding CaF2, all the linear flux ingredients have an increasing effect on the microhardness of the weld metal. Increased binary effect of Al2O3.CaF2, Al2O3.MgO, and MgO.CaF2 flux ingredients are found on the UTS, percentage elongation, impact strength and microhardness of the weldment. For the adequacy of the developed regression model, analysis of variance (F-statistics) is used for all the regression equations.
Quantum teleportation of incomplete multi-quantum systems
Authors: Wu Yingqi , Jin Yuanfeng , Liu Yang , Lyu Gang 
Published: January 2025

Abstract
This paper proposes a quantum teleportation scheme for incomplete multi-quantum systems. According to the structure of the transport state, the number and structure of the quantum channel can be determined, as well as the quantum circuit for quantum teleportation. Compared to previous quantum teleportation protocols, this scheme reduces both the number of qubits in the channel and the amount of classical communication required, thereby enhancing the efficiency of quantum teleportation. Furthermore, this approach offers a new path for constructing non-maximally entangled state channels, which is beneficial for building complex quantum networks and enabling Multi-party quantum teleportation.
Personalized µ-transcranial alternating current stimulation improves online brain–computer interface control
Authors: H Liu Deland , Kumar Satyam , Alawieh Hussein , Samuel Racz Frigyes , del R Millán José 
Published: January 2025

Abstract

Objective. A motor imagery (MI)-based brain–computer interface (BCI) enables users to engage with external environments by capturing and decoding electroencephalography (EEG) signals associated with the imagined movement of specific limbs. Despite significant advancements in BCI technologies over the past 40 years, a notable challenge remains: many users lack BCI proficiency, unable to produce sufficiently distinct and reliable MI brain patterns, hence leading to low classification rates in their BCIs. The objective of this study is to enhance the online performance of MI-BCIs in a personalized, biomarker-driven approach using transcranial alternating current stimulation (tACS). Approach. Previous studies have identified that the peak power spectral density value in sensorimotor idling rhythms is a neural correlate of participants’ upper limb MI-BCI performances. In this active-controlled, single-blind study, we applied 20 min of tACS at the participant-specific, peak µ frequency in resting-state sensorimotor rhythms (SMRs), with the goal of enhancing resting-state µ SMRs. Main results. After tACS, we observed significant improvements in event-related desynchronizations (ERDs) of µ SMRs, and in the performance of an online MI-BCI that decodes left versus right hand commands in healthy participants (N = 10)—but not in an active control-stimulation control group (N = 10). Lastly, we showed a significant correlation between the resting-state µ SMRs and µ ERD, offering a mechanistic interpretation behind the observed changes in online BCI performances. Significance. Our research lays the groundwork for future non-invasive interventions designed to enhance BCI performances, thereby improving the independence and interactions of individuals who rely on these systems.
Unsupervised, piecewise linear decoding enables an accurate prediction of muscle activity in a multi-task brain computer interface
Authors: Ma Xuan , Rizzoglio Fabio , Bodkin Kevin L , Miller Lee E 
Published: January 2025

Abstract
Objective. Creating an intracortical brain-computer interface (iBCI) capable of seamless transitions between tasks and contexts would greatly enhance user experience. However, the nonlinearity in neural activity presents challenges to computing a global iBCI decoder. We aimed to develop a method that differs from a globally optimized decoder to address this issue. Approach. We devised an unsupervised approach that relies on the structure of a low-dimensional neural manifold to implement a piecewise linear decoder. We created a distinctive dataset in which monkeys performed a diverse set of tasks, some trained, others innate, while we recorded neural signals from the motor cortex (M1) and electromyographs (EMGs) from upper limb muscles. We used both linear and nonlinear dimensionality reduction techniques to discover neural manifolds and applied unsupervised algorithms to identify clusters within those spaces. Finally, we fit a linear decoder of EMG for each cluster. A specific decoder was activated corresponding to the cluster each new neural data point belonged to. Main results. We found clusters in the neural manifolds corresponding with the different tasks or task sub-phases. The performance of piecewise decoding improved as the number of clusters increased and plateaued gradually. With only two clusters it already outperformed a global linear decoder, and unexpectedly, it outperformed even a global recurrent neural network (RNN) decoder with 10-12 clusters. Significance. This study introduced a computationally lightweight solution for creating iBCI decoders that can function effectively across a broad range of tasks. EMG decoding is particularly challenging, as muscle activity is used, under varying contexts, to control interaction forces and limb stiffness, as well as motion. The results suggest that a piecewise linear decoder can provide a good approximation to the nonlinearity between neural activity and motor outputs, a result of our increased understanding of the structure of neural manifolds in motor cortex.