bluuebunny/crossref_metadata_2025 huggingface dataset:
A self-referenced optical phase noise analyzer for quantum technologies
Authors: Freund R. , Marciniak Ch. D. , Monz T.
Published: June 2024

Second generation quantum technologies aim to outperform classical alternatives by utilizing engineered quantum systems. Maintaining the coherence required to enable any quantum advantage requires detailed knowledge and control over the noise that the hosting system is subjected to. Characterizing noise processes via their power spectral density is routinely done throughout science and technology and can be a demanding task. Determining the phase noise power spectrum in leading quantum technology platforms, for example, can be either outside the reach of many phase noise analyzers or prohibitively expensive. In this work, we present and characterize a low-complexity, low-cost optical phase noise analyzer based on the short-delay optical self-heterodyne measurements for quantum technology applications. Using this setup, we compare two ≈1 Hz linewidth ultra-stable oscillators near 729 nm. Their measurements are used as a baseline to determine and discuss the noise floor achieved in this measurement apparatus with a focus on limitations and their tradeoffs. The achieved noise floor in this all-stock-component implementation of an optical phase noise analyzer compares favorably with commercial offerings. This setup can be used particularly without a more stable reference or operational quantum system as a sensor as would be the case for many component manufacturers.
Investigation of collision effects on ion dynamics in the presheath and sheath of weakly collisional and magnetized hydrogen plasmas
Authors: Lee Myeong-Geon , Kim Nam-Kyun , Song Jaemin , Roh Ki-Baek , Huh Sung-Ryul , Kim Gon-Ho
Published: June 2024

The effect of collisions on the motion of magnetized ions in sheath and presheath plasma regions was investigated through the measurement of ion incident angle of a hydrogen ion at a graphite surface. The experiment was conducted in hydrogen and deuterium plasmas where the ion mean free path is 5–10 times larger than the ion gyro radius and with varying magnetic field angle ψ from 0° to 90° normal to the target surface. The hydrogen ions actively reacted with carbon, leading to the formation of conical tips with axes directed along the incident ion flow direction. The ion incident angle was measured from the etched graphite images taken by scanning electron microscopy. The measured angles were compared to those calculated using Ahedo's fluid magnetic sheath model. In addition, we adopted the nominal Bohm criterion at the electrostatic sheath edge due to the larger ion gyro radius than the sheath. The results show that the ion incident angle was inclined to the normal direction with respect to the magnetic field angle because of the effect of ion collisions on ion motion in the presheath. The collisional effect on the ion motion is drastic for an oblique magnetic field angle ψ > 85°. This study demonstrates that the collisional property of the ions is crucial to guide the ion motion in magnetic (pre)sheath and to determine the ion incidence angle at the surface, even in collisionless and weakly magnetized plasmas.
Demonstrating grating-based phase-contrast imaging of laser-driven shock waves
Authors: Wegert Leonard , Schreiner Stephan , Rauch Constantin , Albertazzi Bruno , Bleuel Paulina , Fröjdh Eric , Koenig Michel , Ludwig Veronika , Martynenko Artem S. , Meyer Pascal , Mozzanica Aldo , Müller Michael , Neumayer Paul , Schneider Markus , Triantafyllidis Angelos , Zielbauer Bernhard , Anton Gisela , Michel Thilo , Funk Stefan
Published: June 2024

Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock waves. Employing a two-grating Talbot interferometer, we successfully acquire standard absorption, differential phase-contrast, and dark-field images of the shocked target. Good agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser–plasma interaction. The main sources of image noise are identified through a thorough assessment of the interferometer’s performance. The acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density science. In addition, we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.
Separated striations in n-type Czochralski silicon solar cells
Authors: Li Guixiu , Yuan Shuai , Zhou Shenglang , Wu Yihua , Chen Hongrong , Zhang Huali , Wang Chen , Wang Lei , Yu Xuegong , Yang Deren
Published: June 2024

Currently, in the photovoltaic industry, the market share of n-type monocrystalline silicon is rapidly increasing. However, during mass production, striation defects characterized by concentric circles significantly impact the efficiency of solar cells. In this paper, we investigate the properties and origins of striations in n-type Czochralski silicon solar cells. These striations, occurring in wafers with an oxygen concentration below 7 × 1017 cm−3, are shown to potentially cause an efficiency degradation up to 0.86% absolute. Through an array of techniques, including photoluminescence, optical microscopy (OM), electron beam induced current (EBIC), and Fourier Transform Infrared Spectroscopy, this work demonstrates that such defects primarily form after the thermal treatment processes in the manufacturing of solar cells and indirectly proves that these defects are related to the precipitation behavior of oxygen. Notably, traditional methods of post-polishing and etching followed by OM and EBIC technique failed to detect these defects. Therefore, the indirect characterization methods designed in this study hold significant referential value.
Kerr nonlinearity and parametric amplification with an Al-InAs superconductor–semiconductor Josephson junction
Authors: Hao Z. , Shaw T. , Hatefipour M. , Strickland W. M. , Elfeky B. H. , Langone D. , Shabani J. , Shankar S.
Published: June 2024

Nearly quantum limited Josephson parametric amplifiers (JPAs) are essential components in superconducting quantum circuits. However, higher order nonlinearities of the Josephson cosine potential are known to cause gain compression, therefore limiting scalability. In an effort to reduce the fourth order, or Kerr nonlinearity, we realize a parametric amplifier with an Al-InAs superconductor–semiconductor hybrid Josephson junction (JJ). We extract the Kerr nonlinearity of the Al-InAs JJ from two different devices and show that it is three orders of magnitude lower compared to an Al-AlOX junction with identical Josephson inductance. We then demonstrate a four-wave-mixing (4WM) parametric amplifier made with an Al-InAs junction that achieves more than 20 dB of gain and −119 dBm of compression power, which outperforms single resonant JPAs based on Al junctions.
Damping monitoring methods during ultrasonic fatigue testing: A comparative study
Authors: Liu Bofeng , Li Faxin
Published: June 2024

Ultrasonic fatigue testing is quite a useful tool for exploring the high-cycle and very-high-cycle fatigue properties of materials. Damping monitoring has been proved to be fairly effective in indicating the generated defects or damage in the testing specimen. In this work, two damping monitoring methods are comparatively studied, i.e., our recently proposed quantitative electromechanical impedance method and the traditional vibration-free decay method. Industrial pure copper and 6061 aluminum alloy are used for fatigue testing and damping monitoring. To exclude the differences of temperature effect on the testing system, the same duty ratio of 15.4% is employed in the ultrasonic fatigue testing. The results show that both methods can effectively monitor the system damping during testing and the damping evolution process just before failure. Specifically, the free decay method can obtain more damping data and has advantages in monitoring metals, such as aluminum alloys, whose fracture process is very quick. However, the system damping obtained by free decay is strongly dependent on the testing stresses and signal processing and is thus not suitable for failure prediction of specimens. In comparison, the system damping obtained by using the quantitative electromechanical impedance method is independent of the testing stresses. Thus, a definite relationship between the system damping and specimen’s internal friction can be established. However, tens of seconds are required for accurate damping measurement using the quantitative electromechanical impedance method, leading to a low duty ratio of the ultrasonic fatigue testing. In practical, both the methods are suggested for monitoring of early damage during ultrasonic fatigue testing.
Oxygen diffusion coefficients in ferroelectric hafnium zirconium oxide thin films
Authors: Shvilberg Liron , Zhou Chuanzhen , Lenox Megan K. , Aronson Benjamin L. , Lam Nicolas K. , Jaszewski Samantha T. , Opila Elizabeth J. , Ihlefeld Jon F.
Published: June 2024

Oxygen diffusion coefficients in the metastable ferroelectric phase of polycrystalline hafnium zirconium oxide (HZO) thin films have been quantified using 18O tracers and time-of-flight secondary ion mass spectrometry. 11.5 nm thick HZO films containing 16O were deposited by plasma-enhanced atomic layer deposition followed by post-metallization annealing to crystallize into the ferroelectric phase. A 1.2 nm thick HZO layer containing 18O was then deposited using thermal atomic layer deposition with H218O as a reactant. Thermal anneals were conducted at 300, 350, and 400 °C and the ferroelectric phase confirmed after the anneals by x-ray diffraction, infrared spectroscopy, and electrical property measurements. 18O depth profiles were measured and fit with a thin film diffusion equation to determine the oxygen diffusion coefficients. Oxygen diffusion coefficients ranged from approximately 2 × 10−18 cm2/s at 300 °C to 5 × 10−17 cm2/s at 400 °C with an activation energy of 1.02 ± 0.24 eV.
Simulating multipulse NMR spectra of polycrystalline solids in the frequency domain
Authors: Srivastava Deepansh J. , Grandinetti Philip J.
Published: June 2024

An approach is presented for simulating multipulse nuclear magnetic resonance (NMR) spectra of polycrystalline solids directly in the frequency domain. The approach integrates the symmetry pathway concept for multipulse NMR with efficient algorithms for calculating spinning sideband amplitudes and performing interpolated finite-element numerical integration over all crystallite orientations in a polycrystalline sample. The numerical efficiency is achieved through a set of assumptions used to approximate the evolution of a sparse density matrix through a pulse sequence as a set of individual transition pathway signals. The utility of this approach for simulating the spectra of complex materials, such as glasses and other structurally disordered materials, is demonstrated.
A portable self-powered biosensor for monitoring artistic gymnastics techniques
Authors: Liu Datian , Wang Yunlu , Feng Qingyang , Zhang Mengqi , Mao Yupeng , Hu Pei
Published: June 2024

The development of self-powered smart biosensors has attracted great attention due to their potential applications in human motion monitoring and energy collection systems. Here, a newly designed triboelectric nanogenerator (PSP-TENG) composed of the PU sponge, polytetrafluoroethylene, and polydimethylsiloxane for monitoring rear leg rotation motion in artistic gymnastics has been developed. The PSP-TENG can monitor the buffering and stretching time of rear leg rotation and identify the angle between the hip, knee, and ankle during the stretching stage. Furthermore, the PSP-TENG has the function of converting measured signals into power signals, which can convert collected human motion mechanical energy into electrical energy to power wearable devices. The development of PSP-TENG has made contributions to the field of human motion monitoring, providing ideas for new energy and technologies to improve the environment and promote a virtuous ecological cycle.
A triboelectric nanogenerator based on TPU/PVDF electrospinning for mechanical energy harvesting and monitoring running step rate
Authors: Zhou Huafeng
Published: June 2024

Wearable fiber flexible sensors for sports motion monitoring have recently received attention. However, wearable flexible sensors still face limitations in material and device design. Here, we proposed a thermoplastic polyurethane (TPU)/polyvinylidene fluoride (PVDF) film as triboelectric material to manufacture triboelectric nanogenerator (TP-TENG) for harvesting mechanical energy and athlete step rate monitoring. The TPU/PVDF fiber film can be fabricated by using electrospinning technology. In addition, the role of negative triboelectric materials is played by TPU/PVDF film, and the nylon film acts as a positive triboelectric material. The TP-TENG device follows a single-electrode working mode, and it is easy to integrate into human clothing. The TP-TENG electrical output can achieve the maximum output when the content of PVDF in TPU/PVDF film reaches 15%. The TP-TENG can acquire the maximum output power of 699 µW under a 7 MΩ load. Also, the TP-TENG can be used as an electronic skin to achieve self-powered pressure sensing, and the sensitivity of the pressure sensor based on TP-TENG can reach 14.08 V N−1. By integrating it inside the shoes, TP-TENG can obtain the pace rate of runners for sports motion monitoring. This research reports an effective method for monitoring step rate in running and has potential application value.
Interaction between a nonspherical pulsating bubble and a free surface near a solid wall
Authors: Wang Hui , Liu Yun-Long , Qin Hao , Tian Zhao-Li , Yang Di
Published: June 2024

The pulsating bubble near different boundaries demonstrates various dynamics. In this study, the three-dimensional Eulerian finite element method with the adaptive mesh refinement technique was used to investigate the interaction between a bubble and a free surface near a solid wall, including the toroidal bubble motion after the jet impact. The impact pressure on the solid wall was investigated, and the changing trend of pressure peak reverses when the initial depth of the bubble center is between 0.7 and 0.9 times the bubble's maximum radius. Throughout the process, competition occurs between the Bjerknes effects of the free surface and solid wall, which leads to the nonspherical pulsation of the bubble. Different collapsing forms of bubbles, i.e., the strong jet, weak jet, and crescent-type forms, were identified. Greater depth may result in a reduced height of a free surface water column, which is described in a fitting curve. Additionally, inclination of the solid wall can cause the free surface to exhibit a side hump or groove phenomenon. But for a large-scale bubble, no groove phenomenon of the free surface occurred, and the bubble collapsed in a horn-shaped form with two jets in the upward and downward directions.
Stable 500 kW average power of infrared light in a finesse 35 000 enhancement cavity
Authors: Lu X.-Y. , Chiche R. , Dupraz K. , Johora F. , Martens A. , Nutarelli D. , Peinaud Y. , Soskov V. , Stocchi A. , Zomer F. , Michel C. , Pinard L. , Cormier E. , Lhermite J. , Liu X. , Tian Q.-L. , Yan L.-X. , Huang W.-H. , Tang C.-X. , Fedosseev V. , Granados E. , Marsh B.
Published: June 2024

Advances in laser technology over the past 25 years have been impressive, in particular, for the Ytterbium technology where, nowadays, kilowatt-class laser systems are available. This technology also led to the possibility to provide hundreds of kilowatts of laser power by the use of enhancement cavities. We report here on the demonstration of a stable 500 kW average laser power in a high-finesse enhancement cavity. It paves the way toward systems providing laser power in excess of 1 MW and opens the door to a breakthrough in a variety of future applications.
Calculation of quasi-diabatic states within the DFT/MRCI(2) framework: The QD-DFT/MRCI(2) method
Authors: Neville Simon P. , Schuurman Michael S.
Published: June 2024

We describe a procedure for the calculation of quasi-diabatic states within the recently introduced DFT/MRCI(2) framework [S. P. Neville and M. S. Schuurman, J. Chem. Phys. 157, 164103 (2022)]. Based on an effective Hamiltonian formalism, the proposed procedure, which we term QD-DFT/MRCI(2), has the advantageous characteristics of being simultaneously highly efficient and effectively black box in nature while directly yielding both quasi-diabatic potentials and wave functions of high quality. The accuracy and efficiency of the QD-DFT/MRCI(2) formalism are demonstrated via the simulation of the vibronic absorption spectra of furan and chlorophyll a.
Luminescence properties of endohedrally doped group-IV clusters
Authors: Yang Xiaowei , Liu Nanshu , Zhao Jijun , Zhou Si
Published: June 2024

Endohedrally doped clusters form a large category of cage clusters, with unique structures, diverse elemental compositions, and highly tunable electronic structures and physisochemical properties. They have been widely achieved in laboratory and may serve as functional building blocks for assembling new supermolecular structures and devices. In this paper, for the first time, we disclosed the luminescence properties of endohedrally doped group-IV clusters by time-dependent density functional theory calculations. A total of 64 cage clusters have been explored in terms of stability, emission wavelength, and the energy difference between the first excited singlet and triplet states. The key geometric and electronic factors governing the photophysical properties of these cage clusters were unveiled, to provide crucial insights for crafting atomically precise nanoclusters for optical and optoelectronic applications.
Multilayered magnetoelectric composites for precise and wide-range current sensing
Authors: Chu Zhaoqiang , Cui Jianyu , Wang Yanpan , Du ZeLin , PourhosseiniAsl MohammadJavad , Li Nini , Dan Wei , Gao Xiaoyi , Liang Xianfeng
Published: June 2024

Magnetoelectric (ME) sensors are widely studied and well suited for current condition monitoring in smart grids due to their high sensitivity, low power consumption, and compact size. However, designing ME sensors that simultaneously achieve low magnetic noise and a large linear range remains challenging. In this work, we propose and systematically study a multilayered magnetoelectric sensor (MLMS). We experimentally demonstrate that the voltage noise is effectively suppressed by connecting the piezoelectric elements of the MLMS in series. Additionally, the magnetic flux concentration effect is weakened by magnetic shielding from the outer Metglas laminates, which increases the optimized bias field to 52 Oe for the MLMS. Consequently, an equivalent magnetic noise as low as 16.7 pT/rtHz at 1 Hz is obtained and an enlarged linear range from 20 pT to 2 mT is achieved. Furthermore, we demonstrate that the proposed MLMS could linearly detect a wide range of power currents from 0.1 mA to 400 A, with nonlinear error and current resolution as low as 0.05% and 0.1 mA, respectively.
Differential effect of melatonin on ram spermatozoa depending on the allelic variant of the RsaI polymorphism of the MTR1A gene, incubation medium and season
Authors: Peña-Delgado Victoria , Noya Agustí , Carvajal-Serna Melissa , Abecia José A , Pérez-Pe Rosaura , Casao Adriana
Published: June 2024

Context The RsaI polymorphism of the melatonin receptor MTNR1A gene affects seasonal reproduction in sheep, but its effect on ram spermatozoa and their response to melatonin is unknown. Aims This study aims to evaluate whether RsaI polymorphism of the MTNR1A gene influences the response of ram spermatozoa to in vitro added melatonin. Methods Spermatozoa from rams carrying different RsaI allelic variants were incubated with melatonin in a TALP medium or a capacitation-triggering medium during the reproductive and non-reproductive seasons. After incubation, sperm motility, membrane integrity, mitochondria activity, oxidative damage, apoptotic markers and capacitation status were assessed. Key results In the reproductive season, the T/T genotype was related to some adverse effects of melatonin when spermatozoa were incubated in TALP medium, whereas the C/C genotype was linked with adverse effects when the hormone was added in a capacitation-triggering medium. The decapacitating effect of melatonin on spermatozoa was also different depending on genotype. Conclusions The melatonin effect on spermatozoa from rams carrying different RsaI genotypes differed depending on the season and the medium. Implications The knowledge of the RsaI allelic variant of the MTNR1A gene of rams could be helpful when carrying out in vitro reproductive techniques in the ovine species.
Membrane nanotubes transform into double-membrane sheets at condensate droplets
Authors: Zhao Ziliang , Satarifard Vahid , Lipowsky Reinhard , Dimova Rumiana
Published: June 2024

Cellular membranes exhibit a multitude of highly curved morphologies such as buds, nanotubes, cisterna-like sheets defining the outlines of organelles. Here, we mimic cell compartmentation using an aqueous two-phase system of dextran and poly(ethylene glycol) encapsulated in giant vesicles. Upon osmotic deflation, the vesicle membrane forms nanotubes, which undergo surprising morphological transformations at the liquid–liquid interfaces inside the vesicles. At these interfaces, the nanotubes transform into cisterna-like double-membrane sheets (DMS) connected to the mother vesicle via short membrane necks. Using super-resolution (stimulated emission depletion) microscopy and theoretical considerations, we construct a morphology diagram predicting the tube-to-sheet transformation, which is driven by a decrease in the free energy. Nanotube knots can prohibit the tube-to-sheet transformation by blocking water influx into the tubes. Because both nanotubes and DMSs are frequently formed by cellular membranes, understanding the formation and transformation between these membrane morphologies provides insight into the origin and evolution of cellular organelles.
Democratizing protein language models with parameter-efficient fine-tuning
Authors: Sledzieski Samuel , Kshirsagar Meghana , Baek Minkyung , Dodhia Rahul , Lavista Ferres Juan , Berger Bonnie
Published: June 2024

Proteomics has been revolutionized by large protein language models (PLMs), which learn unsupervised representations from large corpora of sequences. These models are typically fine-tuned in a supervised setting to adapt the model to specific downstream tasks. However, the computational and memory footprint of fine-tuning (FT) large PLMs presents a barrier for many research groups with limited computational resources. Natural language processing has seen a similar explosion in the size of models, where these challenges have been addressed by methods for parameter-efficient fine-tuning (PEFT). In this work, we introduce this paradigm to proteomics through leveraging the parameter-efficient method LoRA and training new models for two important tasks: predicting protein–protein interactions (PPIs) and predicting the symmetry of homooligomer quaternary structures. We show that these approaches are competitive with traditional FT while requiring reduced memory and substantially fewer parameters. We additionally show that for the PPI prediction task, training only the classification head also remains competitive with full FT, using five orders of magnitude fewer parameters, and that each of these methods outperform state-of-the-art PPI prediction methods with substantially reduced compute. We further perform a comprehensive evaluation of the hyperparameter space, demonstrate that PEFT of PLMs is robust to variations in these hyperparameters, and elucidate where best practices for PEFT in proteomics differ from those in natural language processing. All our model adaptation and evaluation code is available open-source at
https://github.com/microsoft/peft_proteomics
. Thus, we provide a blueprint to democratize the power of PLM adaptation to groups with limited computational resources.
Sanur Village Festival: A Local Community-Based Event
Authors: Tunjungsari Komang Ratih , Arianty Anak Agung Ayu Arun Suwi , Dewi I Gusti Ayu Melistyari , Suwintari I Gusti Ayu Eka
Published: June 2024

This case study identifies the Sanur Village Festival’s (SVF) success factors as a community event. The Sanur Development Foundation, also known as Yayasan Pembangunan Sanur (YPS) in Bahasa, established the SVF in 2006 following the second Bali Bombing in 2005. The first Bali Bombing in 2002 led to a decrease in tourist numbers, and the same effect was observed after the second Bali Bombing in 2005. Sanur is one of the tourist destinations in Bali whose income relies heavily upon tourists and was affected by both incidents. Therefore, YPS created the SVF to show that Bali, particularly Sanur, is safe to visit and to increase the number of tourists after the incidents. The discussion provided in this case study is based on semi-structured interviews with three interviewees who are Sanur locals. This case shows that leadership, community participation, the organizers, funding, volunteers, booths and activities, location, and safety contributed to the success of the SVF.

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© The Authors 2024
Bayesian interface technique-based inverse estimation of closure coefficients of standard

k
−
ϵ

turbulence model by limiting the number of DNS data points for flow over a periodic hill
Authors: Kumar Chaurasia Nagendra , Chakraborty Shubhankar
Published: June 2024

Among different numerical methods for modeling turbulent flow, Reynolds-averaged Navier–Stokes (RANS) is the most commonly used and computationally reasonable. However, the accuracy of RANS is lower than that of other high-fidelity numerical methods. In this work, the uncertainties associated with the coefficients of the standard

k
−
ϵ

RANS turbulence model are estimated and calibrated to improve the accuracy. The calibration is performed by considering the coefficients individually as well as collectively. The first three coefficients of the standard

k
−
ϵ

turbulence model are calibrated among the five coefficients (

C

μ

,

C

ϵ
1

,

C

ϵ
2

,

σ

ϵ

and σ

k
). The Bayesian inference technique using the Metropolis–Hastings algorithm is applied to quantify uncertainties and calibration. Flow over a periodic hill is selected as a test case. The separation height of the bubble at

x

/

h
=
2

and

x

/

h
=
4

, along with the streamwise velocity at various locations, has been chosen as the quantities of interest for comparing the results with DNS. The calibration is performed using known high-fidelity data (direct numerical simulation) from the available data set. The velocity field is re-calculated from the calibrated closure coefficients and compared with the same calculated with the standard coefficients of

k
−
ϵ

turbulence model (baseline). The deviation of calibrated C

µ
is almost 50%–60% from baseline and for

C

ϵ
1

and

C

ϵ
2

it is 3%–12% and 6%–9% respectively. The algorithm is tested for different Reynold numbers and data points. A sensitivity analysis is also performed.
Ill-posedness of time-dependent inverse problems in Lebesgue-Bochner spaces
Authors: Burger Martin , Schuster Thomas , Wald Anne
Published: June 2024

We consider time-dependent inverse problems in a mathematical setting using Lebesgue-Bochner spaces. Such problems arise when one aims to recover parameters from given observations where the parameters or the data depend on time. There are various important applications being subject of current research that belong to this class of problems. Typically inverse problems are ill-posed in the sense that already small noise in the data causes tremendous errors in the solution. In this article we present two different concepts of ill-posedness: temporally (pointwise) ill-posedness and uniform ill-posedness with respect to the Lebesgue-Bochner setting. We investigate the two concepts by means of a typical setting consisting of a time-depending observation operator composed by a compact operator. Furthermore we develop regularization methods that are adapted to the respective class of ill-posedness.
Rolling bearing fault diagnosis in electric motors based on IDIG-GAN under small sample conditions
Authors: Song Xiangjin , Liu Zhicheng , Wang Zhaowei
Published: June 2024

The bearing fault diagnosis based on deep learning algorithms requires a substantial amount of data. However, in practical industrial production, the diagnostic algorithms tend to work ineffectively due to the limitations of samples. Therefore, in this article, we propose an improved method of deep convolutional generative adversarial networks (DCGAN) with discriminator gradient gap regularization (IDIG-GAN), which can effectively solve the problems of unstable training and poor training performance under a small sample dataset. Firstly, the self-attention mechanism is integrated into the DCGAN to capture global information to enhance the generalization capability of the network. Moreover, gradient normalization is applied to the discriminator to address the problem of vanishing gradients in the network. Furthermore, gradient gap regularization is incorporated into the loss function to narrow the gap between the discriminator gradient norms, thereby improving network stability when dealing with small fault datasets. Through training with the improved IDIG-GAN, then the generated samples are used to expand the dataset and construct a fault diagnosis model. By verifying under two bearing datasets, the results demonstrate that the proposed method can generate high-quality samples and effectively enhance the diagnostic capability of the network when working with small datasets.
SCAPS 1D based study of hole and electron transfer layers to improve MoS2–ZrS2 solar cell efficiency
Authors: Shah Bhoomi S , Tailor Jiten P , Chaki Sunil H , Deshpande M P
Published: June 2024

In the realm of photovoltaic applications, scientists and technocrats are striving to maximize the solar cell input photon energy conversion to electricity. However, achieving optimal cell efficiency requires significant time and energy investment for each variation and optimization. To overcome this issue authors simulated and studied the fabricated cell for optimizing conditions, which can save time and efforts for the relatively better outcomes. The family of transition metal chalcogenides holds promise as a material that yield improved outcomes in optoelectronic applications, particularly in photovoltaics. These materials are employed in experimental investigations aimed at enhancing solar cell parameters, resulting in the development of the FTO/ZnO/ZrS2/MoS2/CuO/Au composite cell. Numerical simulations utilizing SCAPS-1D software is conducted, focusing on the significance of CuO as a hole transport layer (HTL), and ZnO as an electron transport layer (ETL). The investigation examines into the impact of various factors, including thickness, bandgap, and carrier densities for both HTL and ETL, on fundamental solar cell parameters. The study indicates that device parameters are influenced by factors such as recombination rate, photogenerated current, charge carrier length, and built-in-voltage. Optimized parameters for HTL, including thickness, bandgap, and carrier concentration, are determined to be 0⋅35 μm, 1⋅2 eV, and 1⋅0 × 1020 cm–3, respectively. For ETL, the optimized parameters are found to be 0⋅05 μm, 3⋅1 eV, and 1⋅0 × 1018 cm–3, respectively. With these optimized parameters, the efficiency of the solar cell reached 20⋅64%, accompanied by open circuit voltage, short circuit current density, and fill factor values of 0.836 V, 36.021 mA⋅cm–2, and 68⋅54%, respectively. The simulated results indicate that addition of two extra layers and the use of efficient binary materials in heterojunction formation can effectively enhance device parameters, offering advantages such as low-cost and large-scale fabrication.
A DFT study on structural, electronic, and optical properties of cubic perovskite semiconductors InXF3 (X = Be and Ca) for optoelectronic applications
Authors: Mohammed Shoaib Hussain M , Kaleemullah N Syed , Ajay G , Mohamed Sheik Sirajuddeen M
Published: June 2024

First principles calculations were employed to study the structural, electronic and optical properties of Indium based cubic perovskite materials, specifically focusing on InBeF3 and InCaF3 compounds. The generalized gradient approximation Perdew–Burke–Ernzerhof (GGA_PBE) approximation and Tran–Blaha modified Becke–Johnson (TB-mBJ) approximations were used to study and compare the electronic and optical properties. The compound InBeF3 is predicted to have an indirect band gap of 2.51 eV in GGA_PBE and 2.96 eV in TB-mBJ. InCaF3 is found to have a direct wide band gap of 3.61 eV in GGA_PBE and 4.37 eV in TB-mBJ approximation. The partial density of states predicts the significance of In-5p and F-2p states in the conduction and valence bands, respectively. The dielectric constants decrease under the TB-mBJ approximation, with InCaF3 demonstrating lower values owing to its larger band gap. Optical activity analysis indicates transparency for both compounds with notable absorption peaks, suggesting potential applications in transparent coatings. Refractive indices decrease with photon energy, with values dropping below 1.0 in the TB-mBJ approximation, indicating superluminal behavior in wave propagation. The drop in refractive index value below1.0 is earlier for InCaF3 than InBeF3. Examination of the extinction coefficient reveals UV absorption peaks, indicating potential for optoelectronic applications. From this study it can be noticed that the compounds under study can be used for optoelectronic applications, supported by their predicted structural and optical properties study.
Nanosystems with potential application as carriers for skin depigmenting actives
Authors: Castro Natalia Ruben , Pinto Cristal Dos Santos C , Dos Santos Elisabete P , Mansur Claudia Regina E
Published: June 2024

Hyperpigmentation is a skin disorder characterized by excessive production of melanin in the skin and includes dyschromias such as post-inflammatory hyperchromias, lentigens, melasma and chloasma. Topical products containing depigmenting agents offer a less aggressive treatment option for hyperpigmentation compared to methods like chemical peels and laser sessions. However, some of these agents can cause side effects such as redness and skin irritation. Encapsulating these actives in nanosystems shows promise in mitigating these effects and improving product safety and efficacy. In addition, nanocarriers have the ability to penetrate the skin, potentially allowing for targeted delivery of actives to the affected areas. The most commonly investigated nanosystems are nanoemulsions, vesicular nanosystems and nanoparticles, in which different materials can be used to generate different compositions in order to improve the properties of these nanocarriers. Nanocarriers have already been widely explored, but it is necessary to understand the evolution of these technologies when applied to the treatment of skin hyperchromias. Therefore, this literature review aims to present the state of the art over the last 15 years on the use of nanosystems as a potential strategy for encapsulating depigmenting actives for potential application in cosmetic products for skin hyperchromia. By providing a comprehensive overview of the latest research findings and technological advances, this article can contribute to improving the care and quality of life of people affected by this skin condition.
Evolution of transition metal dichalcogenide film properties during chemical vapor deposition: from monolayer islands to nanowalls
Authors: Loginov A B , Kuvatov M M , Ismagilov R R , Sapkov I V , Fedotov P V , Kleshch V I , Obraztsova E D , Obraztsov A N
Published: June 2024

Unique properties possessed by transition metal dichalcogenides (TMDs) attract much attention in terms of investigation of their formation and dependence of their characteristics on the production process parameters. Here, we investigate the formation of TMD films during chemical vapor deposition (CVD) in a mixture of thermally activated gaseous H2S and vaporized transition metals. Our observations of changes in morphology, Raman spectra, and photoluminescence (PL) properties in combination with in situ measurements of the electrical conductivity of the deposits formed at various precursor concentrations and CVD durations are evidence of existence of particular stages in the TMD material formation. Gradual transformation of PL spectra from trion to exciton type is detected for different stages of the material formation. The obtained results and proposed methods provide tailoring of TMD film characteristics necessary for particular applications like photodetectors, photocatalysts, and gas sensors.
Global transonic solutions of hot-Jupiter model for exoplanetary atmosphere
Authors: Chou Shih-Wei , Huang Bo-Chih
Published: June 2024

In this paper, we make modifications to the original hot-Jupiter model, which addresses the problem of hydrodynamic escape for the planetary atmosphere. The model involves the Euler equation with gravity, tidal effect, and heat. We employ the generalised Glimm technique to prove the presence of transonic solutions to the problem. By adjusting the dilation of the characteristic fields, we enhance the accuracy of the Glimm–Goodman wave interaction estimates. This allows us to establish a more general admissible condition for stabilizing the generalised Glimm scheme. Additionally, we derive the exact relationship between the lower bound of the gas velocity in the subsonic state and the adiabatic constant of the gas. Under certain constraints on the transonic initial and boundary data, the limit of the approximation solutions represents an entropy transonic solution with bounded variations. Furthermore, we are able to determine the feasible hydrodynamical region directly from the equation itself, without the need for any additional state equation.
Elementary catastrophes underlying bifurcations of vector fields and PDEs
Authors: Jeffrey Mike R
Published: June 2024

A practical method was proposed recently for finding local bifurcation points in an n-dimensional vector field F by seeking their ‘underlying catastrophes’. Here we apply the idea to the homogeneous steady states of a partial differential equation as an example of the role that catastrophes can play in reaction diffusion. What are these ‘underlying’ catastrophes? We then show they essentially define a restricted class of ‘solvable’ rather than ‘all classifiable’ singularities, by identifying degenerate zeros of a vector field F without taking into account its vectorial character. As a result they are defined by a minimal set of r analytic conditions that provide a practical means to solve for them, and a huge reduction from the calculations needed to classify a singularity, which we will also enumerate here. In this way, underlying catastrophes seem to allow us apply Thom’s elementary catastrophes in much broader contexts.
Core inductive electric field during sawtooth crashes on DIII-D
Authors: Benedett T E , Chen J , Brower D L , Ding W X
Published: June 2024

Sawtooth crashes on tokamak plasmas exhibit relaxation much faster than resistive time scales via a mechanism not fully understood. Using core magnetic measurements from the Radial Interferometer-Polarimeter (RIP) diagnostic on the DIII-D tokamak, Grad–Shafranov equilibria constrained by internal magnetic measurements that have high time resolution (

<

1

µs) can be computed, allowing analysis of how equilibrium parameters such as safety factor q, current density J, and parallel electric field

E
∥

, particularly on-axis, evolve. At the sawtooth crash, on-axis safety factor q
0 is observed to rise by 5% but remain below 1 throughout the cycle, and on-axis current density J
0 is observed to drop by 5%. On-axis parallel electric field

E
∥

(
0
)

is found to be balanced by

η

J
0

(resistivity times on-axis current density) except during the 200 µs crash period, where

E
∥

(
0
)

reaches 22 V m−1, exceeding

η

J
0

by a factor of more than 2000. These first measurements in tokamak plasmas verify that generalized Ohm’s law is not balanced during the crash by resistive effects alone; this is a finding expected due to the relaxation being much faster than resistive timescales. Measurement of the electric field during the tokamak sawtooth serves to illuminate the physical mechanisms at work.
A statistical primer on classical period-finding techniques in astronomy
Authors: Giertych Naomi , Shaban Ahmed , Haravu Pragya , P Williams Jonathan
Published: June 2024

The aim of our paper is to investigate the properties of the classical phase-dispersion minimization (PDM), analysis of variance (AOV), string-length (SL), and Lomb–Scargle (LS) power statistics from a statistician’s perspective. We confirm that when the data are perturbations of a constant function, i.e. under the null hypothesis of no period in the data, a scaled version of the PDM statistic follows a beta distribution, the AOV statistic follows an F distribution, and the LS power follows a chi-squared distribution with two degrees of freedom. However, the SL statistic does not have a closed-form distribution. We further verify these theoretical distributions through simulations and demonstrate that the extreme values of these statistics (over a range of trial periods), often used for period estimation and determination of the false alarm probability (FAP), follow different distributions than those derived for a single period. We emphasize that multiple-testing considerations are needed to correctly derive FAP bounds. Though, in fact, multiple-testing controls are built into the FAP bound for these extreme-value statistics, e.g. the FAP bound derived specifically for the maximum LS power statistic over a range of trial periods. Additionally, we find that all of these methods are robust to heteroscedastic noise aimed to mimic the degradation or miscalibration of an instrument over time. Finally, we examine the ability of these statistics to detect a non-constant periodic function via simulating data that mimics a well-detached binary system, and we find that the AOV statistic has the most power to detect the correct period, which agrees with what has been observed in practice.
Extracting the speed of sound in quark–gluon plasma with ultrarelativistic lead–lead collisions at the LHC
Authors:   The CMS Collaboration
Published: June 2024

Ultrarelativistic nuclear collisions create a strongly interacting state of hot and dense quark–gluon matter that exhibits a remarkable collective flow behavior with minimal viscous dissipation. To gain deeper insights into its intrinsic nature and fundamental degrees of freedom, we determine the speed of sound in an extended volume of quark–gluon plasma using lead–lead (PbPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 0.607 nb−1. The measurement is performed by studying the multiplicity dependence of the average transverse momentum of charged particles emitted in head-on PbPb collisions. Our findings reveal that the speed of sound in this matter is nearly half the speed of light, with a squared value of

0.241
±
0.002

(
stat
)
±
0.016

(
syst
)

in natural units. The effective medium temperature, estimated using the mean transverse momentum, is

219
±
8

(
syst
)

MeV

. The measured squared speed of sound at this temperature aligns precisely with predictions from lattice quantum chromodynamic (QCD) calculations. This result provides a stringent constraint on the equation of state of the created medium and direct evidence for a deconfined QCD phase being attained in relativistic nuclear collisions.
Kresling origami derived structures and inspired mechanical metamaterial
Authors: Wang Xiaolei , Qu Haibo , Zhao Kai , Yang Xiao , Guo Sheng
Published: June 2024

Origami has attracted more and more attention due to its exotic mechanical properties, and the inspired metamaterials are also popular. However, the main focus of current research is on existing origami patterns and properties, although new origami patterns or results that expand on existing origami patterns are gradually emerging. In this paper, we summarize a series of derived structures of the Kresling origami, demonstrating more stable states and richer structural forms. At the same time, a point-searching method is proposed along the ideas of the truss model, which is effective for irregular stable states of these derived structures. On this basis, we create an origami-inspired mechanical metamaterial with foldable property and high load-bearing capacity, fabricate the prototype, and validate its performance through experiments. These works make important contributions for promoting the Kresling origami and origami-inspired metamaterials.
Low-frequency electrodynamics in the mixed state of superconducting NbN and a-MoGe films using two-coil mutual inductance technique
Authors: Basistha Somak , Mandal Soumyajit , Jesudasan John , Bagwe Vivas , Raychaudhuri Pratap
Published: June 2024

We investigate the low-frequency electrodynamics in the vortex state of two type-II superconducting films, namely, a moderate-to-strongly pinned Niobium Nitride (NbN) and a very weakly pinned amorphous Molybdenum Germanium (a-MoGe) film. We employ a two-coil mutual inductance technique to extract the complex penetration depth,

λ
~

. The sample response is studied through the temperature variation of

λ
~

in the mixed state, where we employ a model developed by Coffey and Clem (the CC model) to extract different vortex lattice (VL) parameters, such as the restoring pinning force constant (Labusch parameter), VL drag coefficient and pinning potential barrier. We observe that a consistent description of the inductive and dissipative part of the response is only possible when we take the viscous drag on the vortices to be several orders of magnitude larger than the viscous drag estimated from the Bardeen–Stephen model.
Competing interactions in strongly driven multi-level systems
Authors: Bender Jana , Mischke Patrick , Klas Tanita , Binoth Florian , Naim Hani , Ott Herwig , Niederprüm Thomas
Published: June 2024

We experimentally study the level mixing, splitting and repulsion of an optically driven atomic multi-level system under two competing interactions. The strength of the optical coupling is increased until it surpasses the atomic hyperfine interaction responsible for mixing the magnetic substates. Due to the multi-level character of the coupled state space, the level shifts exhibit complex behavior reminiscent of the Paschen–Back effect. Our results show that multi-level effects can have significant influence for strong external drive, differing from a simple model of effective non-interacting two-level systems. These results highlight the relevance of imperfections of the light polarization or initial state preparation in strongly optically driven systems.
Non-local time evolution equation with singular integral and its application to traffic flow model
Authors: Higashi Kohei
Published: June 2024

We consider an integro-differential equation model for traffic flow, which extends the Burgers equation model. To derive exact solutions to the equation, we first examine the features of integrable integro-differential equations and find that they are obtained through the residue formula from integrable equations in complex domains. Using this approach, we construct several new integrable equations with double singular integrals and elliptic singular integrals. Then, we discuss the traffic model and show that it exhibits interactions between free-flow and congested regions, as well as the deadlock phenomenon, depending on the non-locality parameter.