bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced magnetically coupled rotational piezoelectric energy harvesting based on tailored centrifugal distance
Authors: Zhang Yunshun , Wang Xin , Wang Wanshu 
Published: April 2024

Abstract
To tackle the issue of limited operating bandwidth encountered by energy harvesters in high-speed rotating contexts, this paper proposes a method for achieving rotational energy harvesting over a relatively high bandwidth through stabilizing high-energy orbit oscillations based on theoretically tailored centrifugal distance. The interaction between the cantilever beam tip permanent magnet and the fixed end magnet introduces nonlinear factors into the rotating piezoelectric energy harvesting system. By exploiting the non-linear matching relationship between the jump-down frequency under bistable condition and the rotational frequency of the external environment, the centrifugal distance theoretically derived is divided into five distinct conditions. Notably, when the centrifugal distance is in condition of 6.5 cm, optimal alignment and overlap are observed between the jump-down curve and the rotational frequency curve within the rotational frequency range of 40–80 rad s−1. Tailoring of different centrifugal distances across the five conditions is then explored and validated through simulations, including velocity profiles and energy harvesting capabilities. Finally, a rotating experimental platform was constructed and the experimental results validate that, at the theoretically tailored centrifugal distance of 6.5 cm, the rotating energy harvester achieves a peak power output of 127.4 μW within the effective bandwidth of 40–80 rad s−1. This study underscores the significance of tailoring centrifugal distance to stabilize high-energy orbit oscillations, thereby enhancing the energy harvesting potential of the device across a relatively wide range of external rotational frequencies.
3D modeling and measurement of HTS tape stacks in linear superconducting magnetic bearings
Authors: Ghabeli Asef , Fuchs Günter , Hänisch Jens , Zhou Pengbo , de Haas Oliver , Morandi Antonio , Grilli Francesco 
Published: April 2024

Abstract
Superconducting magnetic bearings (SMBs) are among the possible new technologies to be incorporated in maglev vehicles. Stacks of high-temperature superconductor (HTS) tapes can be used as an alternative to bulks, because stacks offer better mechanical properties, a better thermal conductivity and a simpler production process. Numerical modeling has been employed as a cost-effective, fast and reliable tool for improving the performance of SMBs. Several scenarios can be simulated with fast and relatively simple 2D models; however, in some cases using 3D models is inevitable. In this study, we use a full 3D model to solve the problem of magnetization of the tape stacks and obtaining the hysteresis force loop between a permanent magnet and the tape stacks. For this purpose, we employ an energy minimization-based method called minimum electromagnetic entropy production in 3D, combined with a homogenization technique and the

J
c

(
B
,
θ
)

dependence of the HTS tape as input. The modeling results agree very well with the experiment both in the zero-field cooled and field-cooled conditions. The presented approach offers significant computational advantages, delivering faster and more efficient results compared to previously proposed 3D methods.
Unveiling the growth mechanism of FeSeTe films by pulsed laser deposition technique
Authors: Zhang Jia-Ying , He Ya-Xun , He Tian , He Jing-Yu , Wu Wei-Bin , Ge Jun-Yi 
Published: April 2024

Abstract
The superconductivity of FeSeTe films, deposited by the pulsed laser deposition (PLD), is extremely sensitive to the preparation conditions. Hence, it is necessary to study the growth mechanism and reveal the key factors affecting the superconductivity of FeSeTe films. Among all the preparation conditions, the substrate temperature (

T

s

) is one of the most critical one because it can alter the diffusion and nucleation of deposited atoms, as well as subsequent secondary volatilization. In this study, we prepared a series of FeSeTe films deposited on CaF2 substrates with

T

s

ranging from 25 ∘C to 700 ∘C. It is found that the growth mechanism of the FeSeTe films deposited at different

T

s

is determined by the competition between crystallization and volatilization, and the

T

s

can serve as an effective means to regulate the (Se+Te):Fe ratio of the FeSeTe films. The superconductivity of the FeSeTe films is co-modulated by the crystallinity and composition. In addition, the

T

s

can greatly affect the pinning mechanism of the FeSeTe films by introducing the fine nonstoichiometric particles, local chemical inhomogeneity and planar defects. This work facilitates the further performance improvement and practical applications of FeSeTe superconducting films, and is of reference for the FeSeTe film prepared by other deposition methods.
NbN-based tunnel-type π-junctions for low-power half-flux-quantum circuits
Authors: Pham Duong , Li Feng , Oba Kenjiro , Takeshita Yuto , Tanaka Masamitsu , Yamashita Taro , Fujimaki Akira 
Published: April 2024

Abstract
We have developed half-flux-quantum (HFQ) circuits using all-π-junctions formed from an NbN/AlN/PdNi/NbN (SIFS) structure. The circuits were fabricated using a novel process that incorporated a ground plane on top of the chip, enabling the epitaxial growth of NbN-based junctions from the substrate. The π-state of the junctions was demonstrated through a HFQ shift. Notably, these π-junctions exhibited self-overdamped current-voltage characteristics, enabling them to function as switching components without the need for shunt resistors. The elimination of shunt resistors and the high sheet inductance of NbN are expected to enhance the density of HFQ circuits. To evaluate the performance and power consumption of the all-π-junctions HFQ circuits, we designed and fabricated an HFQ toggle flip-flop (HFQ-TFF) circuit utilizing π-π-π SQUIDs as the fundamental components. Our findings reveal that the NbN-based HFQ-TFF circuit correctly operates as a frequency divider while consuming only around 30% of the power compared to single-flux-quantum TFF (SFQ-TFF) circuits. These results suggest that the HFQ circuit using SIFS-π-junctions has promising potential for integrated circuits requiring low-power consumption at cryogenic temperatures, such as qubit control.
Tunable band alignment and optical properties in van der Waals heterostructures based on two-dimensional materials Janus-MoSSe and C3N4
Authors: Pei Shida , Cao Rufeng , Zhou Yan-Hong , Zheng Xiaohong , Wang Caiyun 
Published: April 2024

Abstract
Van der Waals heterostructures with tunable band alignments are the promising candidates for the fabrication of high-performance multifunctional nano-optoelectronic devices. In this work, we investigate the band alignments and optical properties of two-dimensional MoSSe/C3N4 and C3N4/MoSSe heterostructures using first-principles methods. The two most stable MoSSe/C3N4 (C3N4-Se) and C3N4/MoSSe (C3N4-S) heterostructures (labeled as A2 and B2, respectively) out of the twelve possible heterostructures are selected for the corresponding properties research. It is found that the A2 exhibits type-I band alignment, making it suitable for light-emitting applications, while the B2 exhibits typical type-II band alignment, which is favorable for carrier separation. Moreover, the band alignment of the two heterostructures can be modulated by the external electric fields, that is, band alignment transition between type-I and type-II. In addition, the main absorption peaks of both heterostructures in their pristine state are located in the visible light region (approximately 2.9 eV), and the peak values of the absorption peaks can be enhanced (weaken) via applying positive (negative) external electric fields. Our findings demonstrate that the C3N4/C3N4 and C3N4/MoSSe heterostructures hold significant potential for applications in multifunctional electronic devices including light-emitting, carrier separation, optical modulators, etc.
A holistic approach of strain-induced and spin-orbit coupling governed structural, optical, electrical and phonon properties of Janus MoSSe heterostructure via DFT theory
Authors: Pritu Farah B H , Islam Md Rasidul , Jahan Nusrat , Arobi Nourin , Rahman M Mahbubur 
Published: April 2024

Abstract
Spintronics and optoelectronic equipment benefit from efficient modification of electrical and optical characteristics for Van der Waals heterostructures. Janus MoSSe, in two dimensions, has superior electronic, optical, and phonon properties. Based on these characteristics, we evaluate the effects of biaxial compressive and tensile strain ranges of −6% to +6% on the structural, optical, spin–orbit coupling, and phonon properties of two-dimensional MoSSe employing first-principles-based density functional theory calculations. At K-point, MoSSe possesses a direct band gap of 1.665 eV, making it a semiconductor. Yet, applying tensile strain, we can observe that the bandgap of MoSSe has declined. On the other hand, the bandgap of MoSSe rises due to the compressive strain. From the phonon properties, it is clear that the stability of the monolayer MoSSe is observed in the case of tensile strain. With the increase of compressive strain, it loses its stability. With a photon energy of 2.5 eV, MoSSe exhibits three times greater optical absorption than other photon energy levels. In comparison to two monolayers (MoS2, MoSe2), the MoSSe heterostructure shows an elevated optical absorption coefficient in the visible light band, according to our calculations of its dielectric constant and optical absorptionThe MoSSe dielectric constant’s peaks shift to the stronger photon energy as compressive strain is increased; in contrast, if tensile strain is added, the highest points shift to the less powerful photon energy. This suggests that the spin–orbit coupling (SOC) in MoSSe heterostructures can be enhanced under strain, which has implications for spintronics. The effect of strain can be used to tailor the phonon behaviors of MoSSe, which can be useful for controlling the material’s mechanical and thermal characteristics. The versatility of the electronic and optical properties of the material under strain can be harnessed to design novel devices such as strain sensors, optoelectronic modulators, and detectors.
Fast forward modelling of galaxy spatial and statistical distributions
Authors: Berner Pascale , Refregier Alexandre , Moser Beatrice , Tortorelli Luca , Machado Poletti Valle Luis Fernando , Kacprzak Tomasz 
Published: April 2024

Abstract
A forward modelling approach provides simple, fast and realistic simulations of galaxy surveys, without a complex underlying model. For this purpose, galaxy clustering needs to be simulated accurately, both for the usage of clustering as its own probe and to control systematics. We present a forward model to simulate galaxy surveys, where we extend the Ultra-Fast Image Generator to include galaxy clustering. We use the distribution functions of the galaxy properties, derived from a forward model adjusted to observations. This population model jointly describes the luminosity functions, sizes, ellipticities, SEDs and apparent magnitudes. To simulate the positions of galaxies, we then use a two-parameter relation between galaxies and halos with Subhalo Abundance Matching (SHAM). We simulate the halos and subhalos using the fast PINOCCHIO code, and a method to extract the surviving subhalos from the merger history. Our simulations contain a red and a blue galaxy population, for which we build a SHAM model based on star formation quenching. For central galaxies, mass quenching is controlled with the parameter Mlimit, with blue galaxies residing in smaller halos. For satellite galaxies, environmental quenching is implemented with the parameter tquench, where blue galaxies occupy only recently merged subhalos. We build and test our model by comparing to imaging data from the Dark Energy Survey Year 1. To ensure completeness in our simulations, we consider the brightest galaxies with i < 20. We find statistical agreement between our simulations and the data for two-point correlation functions on medium to large scales. Our model provides constraints on the two SHAM parameters Mlimit and tquench and offers great prospects for the quick generation of galaxy mock catalogues, optimized to agree with observations.
Bubble wall velocities with an extended fluid Ansatz
Authors: Dorsch Gláuber C. , Pinto Daniel A. 
Published: April 2024

Abstract
We compute the terminal bubble wall velocity during a cosmological phase transition by modelling non-equilibrium effects in the plasma with the so-called “extended fluid Ansatz”. A ϕ
6 operator is included in the Standard Model effective potential to mimic effects of new physics. Hydrodynamical heating of the plasma ahead of the bubble is taken into account. We find that the inclusion of higher order terms in the fluid Ansatz is typically relevant, and may even turn detonation solutions into deflagrations. Our results also corroborate recent findings in the literature that, for a Standard Model particle content in the plasma, only deflagration solutions are viable. However, we also show that this outcome may be altered in a theory with a different particle content.
Boundary condition effects on runaway electron mitigation coil modeling for the SPARC and DIII-D tokamaks
Authors: Izzo V.A. , Battey A. , Tinguely R.A. , Sweeney R. , Hansen C. 
Published: April 2024

Abstract
Extended-MHD modeling of planned Runaway Electron Mitigation Coils (REMC) for SPARC and DIII-D is performed with the NIMROD code. A coil has been designed for each machine, with the two differing in shape and location, but both having n = 1 symmetry (with n the toroidal mode number). Compared to previous modeling efforts, three improvements are made to the simulations boundary conditions. First a resistive wall model is used in place of an ideal wall. Second, the ThinCurr code is used to compute the time-dependent 3D fields used as magnetic boundary conditions for the simulations. Third, the simulation boundary is moved from the first-wall location to the Vacuum Vessel (VV), which extends the boundary past the location of the internal REMC. To remove the 3D coil from the simulation domain, an equivalent set of 3D fields is calculated at the VV boundary that produce approximately the same field distribution at the last closed flux surface assuming vacuum between the two. Each of these three boundary condition improvements leads to an improvement in the predicted performance of the REMC for both machines. The resistive wall alone primarily effects the resonance of the coil with the plasma after the TQ, affecting the q-profile evolution in the SPARC modeling, and allowing the applied spectrum to be modified in response to the plasma in the DIII-D modeling. The movement of the simulation boundary has the most significant effect on the RE confinement overall, including in the early stages, particularly for a DIII-D inner wall limited equilibrium, where the RE loss fraction increases from 90% to

>

99%, with SPARC RE losses also occurring much earlier when the boundary is placed at the VV.
Broadening of electron cyclotron power deposition and driven current profiles caused by dissipative diffractive propagation
Authors: Yanagihara K. , Kubo S. 
Published: April 2024

Abstract
Improvements in electron cyclotron resonance heating (ECRH) and current drive (ECCD) predictions are important issues for the design and control of high-performance fusion plasmas in future devices, where these should play a more important role as actuators than in devices to date. A newly developed EC-prediction package based on the quasioptical ray tracing code PARADE revealed in JT-60SA that (i) the radial profiles of both EC power deposition and driven current are broadened and (ii) the net driven current is increased by a few kA/MW, in comparison with conventional predictions due to dissipative diffractive propagation (DDP). The mechanism of DDP is as follows: EC wave beam obliquely passing through the resonant surface is dissipated non-uniformly on its beam cross section, so that the beam trajectory shifts gradually and thus the resonant position also shifts, resulting in the broadened power deposition profile. This novel ECCD and ECRH prediction package based on PARADE is applicable not only to JT-60SA but other existing devices and even, future devices.
Parameter estimation from quantum-jump data using neural networks
Authors: Rinaldi Enrico , González Lastre Manuel , García Herreros Sergio , Ahmed Shahnawaz , Khanahmadi Maryam , Nori Franco , Sánchez Muñoz Carlos 
Published: April 2024

Abstract
We present an inference method utilizing artificial neural networks for parameter estimation of a quantum probe monitored through a single continuous measurement. Unlike existing approaches focusing on the diffusive signals generated by continuous weak measurements, our method harnesses quantum correlations in discrete photon-counting data characterized by quantum jumps. We benchmark the precision of this method against Bayesian inference, which is optimal in the sense of information retrieval. By using numerical experiments on a two-level quantum system, we demonstrate that our approach can achieve a similar optimal performance as Bayesian inference, while drastically reducing computational costs. Additionally, the method exhibits robustness against the presence of imperfections in both measurement and training data. This approach offers a promising and computationally efficient tool for quantum parameter estimation with photon-counting data, relevant for applications such as quantum sensing or quantum imaging, as well as robust calibration tasks in laboratory-based settings.
Extreme small-scale prediction head-based efficient YOLOV5 for small-scale object detection
Authors: Gowthami Nekkanti , Blessy Shalanti Vineetha 
Published: April 2024

Abstract
Recognition models achieved exceptional performance in object detection during the computer vision era, but they still rely on Small-Scale Object Detection (SSOD). SSOD remains difficult due to the variety of shapes and orientations of the object, as well as fixed prediction heads at the detection stage. To overcome these challenges, our paper proposed an auto anchor module, a Spatial Pyramid Pooling Faster layer (SPPF) in the feature refinement network, and an extremely small-scale prediction head at the detection stage of the model. With the auto anchor feature, the model is able to adjust the anchor boxes dynamically during training, which can improve its overall performance. The SPPF layer divides the feature map into five pyramid levels, each corresponding to a different scale. This enables the model to detect objects of different sizes by pooling features from all pyramid levels. Extreme Small Scale prediction head is specifically designed for small object detection and uses anchor boxes with small sizes and feature re-sampling techniques to improve the accuracy of SSOD. We perform quantitative evaluations on the VOC and achieved 85.4% mAP, 79.8% precision, 80.3% recall, and 80% F1-score. These reliable results prove that the suggested model performs better than existing models in detecting small-scale objects.
Review and experimental benchmarking of machine learning algorithms for efficient optimization of cold atom experiments
Authors: Anton Oliver , Henderson Victoria A , Da Ros Elisa , Sekulic Ivan , Burger Sven , Schneider Philipp-Immanuel , Krutzik Markus 
Published: April 2024

Abstract
The generation of cold atom clouds is a complex process which involves the optimization of noisy data in high dimensional parameter spaces. Optimization can be challenging both in and especially outside of the lab due to lack of time, expertise, or access for lengthy manual optimization. In recent years, it was demonstrated that machine learning offers a solution since it can optimize high dimensional problems quickly, without knowledge of the experiment itself. In this paper we present results showing the benchmarking of nine different optimization techniques and implementations, alongside their ability to optimize a rubidium (Rb) cold atom experiment. The investigations are performed on a 3D 87Rb molasses with 10 and 18 adjustable parameters, respectively, where the atom number obtained by absorption imaging was chosen as the test problem. We further compare the best performing optimizers under different effective noise conditions by reducing the signal-to-noise ratio of the images via adapting the atomic vapor pressure in the 2D+ magneto-optical trap and the detection laser frequency stability.
Measure induced Hankel and Toeplitz type operators on weighted Dirichlet spaces
Authors: Zorboska Nina 
Published: April 2024

For a complex Borel measure

μ
\mu

on the open unit disk, and for a weighted Dirichlet space

H

s

\mathcal {H}_s

with

0
>
s
>
1

0>s>1

, we characterize the boundedness of the measure induced Hankel type operator

H

μ
,
s

:

H

s

→

H

s

¯

H_{\mu ,s}: \mathcal {H}_s \to \overline {\mathcal {H}_s}

, extending the results of Xiao [Bull. Austral. Math. Soc. 62 (2000), pp. 135–140] for the classical Hardy space

H
2

=

H

1

H^2=\mathcal {H}_1

, and of Arcozzi, Rochberg, Sawyer, and Wick [J. Lond. Math. Soc. (2) 83 (2011), pp. 1–18] for the classical Dirichlet space

D

=

H

0

\mathcal {D}= \mathcal {H}_0

. Our approach relies on some recent results about weak products of complete Nevanlinna-Pick reproducing kernel Hilbert spaces. We also include some related results on Hankel measures, Carleson measures, and Toeplitz type operators on weighted Dirichlet spaces

H

s

\mathcal {H}_s

,

0
>
s
>
1

0>s>1

.