bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low divergence cold-wall oven for loading ion traps
Authors: Prakash Anand , Ayyadevara Akhil , Krishnakumar E. , Rangwala S. A. 
Published: March 2024

We present a compact cold-wall oven that is simple to build and align for loading miniature ion traps with calcium ions. The cold-wall oven, which is a metal-loaded capillary heated only through a portion of its length by the passage of a current, is described and characterized. An atomic beam with a low divergence of 14 mrad is produced. We perform Doppler-sensitive, resonant fluorescence measurements on the atomic beam to characterize the oven’s performance. The emission of atoms from the oven is seen within ∼70 s after turning on the oven at an electric power consumption of &lt;10 W. The flow rate is measured to be 1.5 ± 0.2 × 109 atoms s−1 at a temperature of 702 ± 7 K. The entire oven assembly is mounted on a CF16 feedthrough. This design can be extended to other species for producing a collimated atomic beam.
SIM.T-K9.3: Standard platinum resistance thermometer ITS-90 realizations from the Hg triple point to the Zn freezing point
Authors: Quelhas Klaus N , Lozano Bruno M , Hamilton Francis 
Published: March 2024

Main text
This report shows the results of a bilateral comparison of temperature standards between Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro, Brazil), and Trinidad and Tobago Bureau of Standards (TTBS, Trinidad and Tobago), carried out between January and July of 2020. The measurands of this comparison were the W(t90) ratios of two Standard Platinum Resistance Thermometers (SPRTs), used as transfer standards, measured at the zinc freezing point (Zn FP, 419.527 °C), tin freezing point (Sn FP, 231.928 °C), gallium melting point (Ga MP, 29.7646 °C), triple point of water (TPW, 0.01 °C) and mercury triple point (Hg TP, -38.8344 °C).
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Controlling of spontaneous emission of quantum dots based on hyperbolic metamaterials
Authors: Mao Yu , Zhang Hao , Xiong Jing , Liu Xiangpeng , Wang Qiaoqiao , Wang Junqiao 
Published: March 2024

Abstract
The study of spontaneous emission has basic and supporting significance for enhancing the interaction between light and matter, solid-state lighting and biosensors. Hyperbolic metamaterials (HMMs) can support high k modes due to their hyperbolic dispersion characteristics, resulting in extremely high photon density, which affects spontaneous emission. Therefore, here we study the effect of HMMs on the spontaneous emission of quantum dots (QDs), and the Purcell factor reaches 20 times. At the same time, the structure of HMMs with gold nanoantennas is studied. The addition of gold nanoantennas further increases the Purcell factor to 120 times. In addition, the effects of the metal filling rate, the position and polarization direction of QDs on spontaneous emission enhancement and radiation power peak position are also studied. This provides a new perspective for enhancing and controlling spontaneous emission of QDs based on HMMs.
Effects of Mn doping on the conduction mechanism and dielectric nonlinearity of Na0.5Bi0.5TiO3 thin film
Authors: Liang Zhongshuai , Shen Cheng-Ao , Wang Jiawei , Liu Xin , Hu Tianyi , Li Chao , Xiong Lilong , Du Xianfeng 
Published: March 2024

Abstract
In this work, the conduction mechanism and dielectric nonlinearity of undoped and Mn-doped Na0.5Bi0.5TiO3 (NBT) films were investigated. The potential conduction mechanism in relatively low electric fields should be dominated by hopping conduction rather than typical Ohmic conduction. In the high electric field region, the conduction mechanism is dominated by Poole–Frenkel emission and Schottky emission. The enhancement of electrical insulation of NBT films after Mn doping was shown to result from a decrease in oxygen vacancies and elevation of the conduction energy barrier. Furthermore, significant improvements in the nonlinearity of both the dielectric constant and polarization of Mn-doped NBT films were observed, as indicated by the results of Rayleigh fitting and first-order reversal curve distributions. Such enhancements were attributed to the reduction in domain wall pinning, decreased interference from electrostatic potential and improved leakage characteristics.
Characterization of tracks from alpha-particles in PADC detectors for passive environmental monitoring of fast neutron radiation field
Authors: Biordi Chantal , Sarchiapone Lucia , Gallo Salvatore 
Published: March 2024

Abstract
Fast neutron dosimetry is particularly crucial in the realm of radioprotection, as it significantly contributes to evaluating the radiation protection measures. This assessment aims to ensure and enhance the effectiveness of implemented safeguards and precautions, thereby minimizing the risks and potential harm associated with radiation exposure. Given the substantial biological damage that fast neutrons can inflict when interacting with living tissues, accurate dosimetry is indispensable for ensuring the safety of personnel in these environments and for optimizing radiation therapy treatments. Employing an indirect detector technique, this research focuses on characterizing the geometrical and optical properties of tracks produced by alpha particles resulting from boron-neutron reactions and distinguish them from the background made up of tracks generated from radon decay and impurities on the surface of the detector. This methodology holds potential utility particularly in situations where dosimeters are not adequately stored: while the idea of employing plastic or alternative materials to shield dosimeters from radon may appear straightforward, there are numerous factors complicating its effectiveness and universal applicability, for example when the radon proof encapsulations are not sealed perfectly. Through the development of a robust protocol for fast neutron dosimetry, we can not only differentiate between tracks produced by alpha particles of varying energy levels but also quantify the dose resulting from exposure to the neutron field. A solid-state nuclear track detector system (Politrack, Mi.am, Italy) was used to address the critical need for measuring exposure to fast neutrons, thermalized by polyethylene spheres. This advancement facilitates the implementation of more effective radioprotection strategies and contributes to the overall safety of radiation therapy procedures.
Thermally stable radiative recombination centers within trench structures of red multi-quantum wells
Authors: Pan Zuojian , Yang Han , Chen Zhizhong , Zhang Haodong , Deng Chuhan , Wang Zeren , Chen Weihua , Kang Xiangning , Jia Chuanyu , Liang Zhiwen , Wang Qi , Zhang Guoyi , Shen Bo 
Published: March 2024

Abstract
High-Indium (In)-content multi-quantum wells (MQWs) are generally thermally unstable due to poor crystal quality resulting from low-temperature growth. In this study, red emission was achieved by modulating trench structures using dual-colour MQW structures. Impressively, the red MQWs inside deep trenches showed excellent thermal stability despite being grown at low temperatures. After high-temperature annealing at 950 °C for 30 min, the photoluminescence (PL) intensity of red MQWs exhibited a significant reduction of 91.9% outside trenches, while it dropped by only 9.3% inside trenches, as confirmed by confocal PL mapping. Transmission electron microscopy results show that massive In-rich phases and stacking faults appeared in the MQWs outside trenches after annealing. By contrast, the red MQWs inside deep trenches remained intact in lattice arrangement without being significantly damaged. The superior thermal stability of red MQWs inside deep trenches was mainly attributed to the low-defect-density epitaxy of InGaN layers in strain-relaxed states.
Goos–Hänchen shift for coupled vibrational modes in a semiconductor structure
Authors: Villegas Diosdado , Lazcano Zorayda , Arriaga Jesús , Pérez-Álvarez R , de León-Pérez Fernando 
Published: March 2024

Abstract
We present a theoretical investigation of the Goös–Hanchen shift (GHS) experienced by acoustic and optical vibrational modes reflected and transmitted from the surfaces of a semiconductor thin film sandwiched between two semi-infinite media. Our study focuses on the impact of the incident angle on the GHS, considering the coupling between longitudinal and transverse modes. For acoustic vibrations, our findings reveal that the GHS can reach magnitudes up to seven times larger than the thickness of the thin film and up to 20 times larger than the incident wavelength. Besides, it is shown that this significant amplification of the GHS highlights the strong influence of the incident angle and the frequency of the modes involved. In the case of optical vibrations, we observe even more pronounced GHS values, exceeding 30 times the incident wavelength. This demonstrates the potential of GHS in acoustical systems, which opens up possibilities for applications in the design of acoustic devices.
Intelligent fault diagnosis for electro-hydrostatic actuator based on multisource information convolutional residual network
Authors: Liu Jiahui , Hu Yuanhao , Zhu Xingjun , Zhao Xiaoli , Gao Guangfa , Yao Jianyong 
Published: March 2024

Abstract
The electro-hydrostatic actuator (EHA), known for its advantages such as minimal throttling loss, high efficiency, and a significant volume-to-power ratio, has found extensive application in the fields of aeronautics and astronautics. However, ensuring the safety of aircraft that utilize EHAs requires efficient fault diagnosis due to the demanding operational conditions and prolonged usage. Traditional diagnostic approaches face challenges such as intricate fault modeling, complex multi-channel monitoring data, and a limited number of fault samples within the electro-hydraulic system. To overcome these challenges, we propose an intelligent diagnosis method based on a multi-source information convolutional residual network. Specifically, a multis-cale kernel is implemented to capture features at different scales, enhancing model expressiveness. The efficiency channel attention mechanism dynamically focuses on relevant channel features to improve feature learning ability. The residual network adaptively recalibrates features at each layer to facilitate fault feature learning. Additionally, the activate or not activation function is introduced to selectively activate shallow features, thereby improving the feature representation and generalization capability of the model. Experimental data from the EHA system validates the superiority of the proposed method, demonstrating a significant enhancement in the diagnostic accuracy of EHAs with limited samples.
pyPPG: a Python toolbox for comprehensive photoplethysmography signal analysis
Authors: Goda Márton Á , Charlton Peter H , Behar Joachim A 
Published: March 2024

Abstract

Objective. Photoplethysmography is a non-invasive optical technique that measures changes in blood volume within tissues. It is commonly and being increasingly used for a variety of research and clinical applications to assess vascular dynamics and physiological parameters. Yet, contrary to heart rate variability measures, a field which has seen the development of stable standards and advanced toolboxes and software, no such standards and limited open tools exist for continuous photoplethysmogram (PPG) analysis. Consequently, the primary objective of this research was to identify, standardize, implement and validate key digital PPG biomarkers. Approach. This work describes the creation of a standard Python toolbox, denoted pyPPG, for long-term continuous PPG time-series analysis and demonstrates the detection and computation of a high number of fiducial points and digital biomarkers using a standard fingerbased transmission pulse oximeter. Main results. The improved PPG peak detector had an F1-score of 88.19% for the state-of-the-art benchmark when evaluated on 2054 adult polysomnography recordings totaling over 91 million reference beats. The algorithm outperformed the open-source original Matlab implementation by ∼5% when benchmarked on a subset of 100 randomly selected MESA recordings. More than 3000 fiducial points were manually annotated by two annotators in order to validate the fiducial points detector. The detector consistently demonstrated high performance, with a mean absolute error of less than 10 ms for all fiducial points. Significance. Based on these fiducial points, pyPPG engineered a set of 74 PPG biomarkers. Studying PPG time-series variability using pyPPG can enhance our understanding of the manifestations and etiology of diseases. This toolbox can also be used for biomarker engineering in training data-driven models. pyPPG is available on https://physiozoo.com/.
Design and analysis of Si photonic NaCl sensors based on suspended microdisk resonators
Authors: Moeinimaleki Kaveh , Habibzadeh-Sharif Amir , Ahmadpour Afshin , Bahrami-Chenaghlou Faezeh 
Published: March 2024

Abstract
In this paper, two optical refractive index sensors, respectively based on a suspended microdisk resonator (SMDR) and a sub-wavelength Bragg grating suspended microdisk resonator (SWG-SMDR) have been designed on a silicon on insulator (SOI) platform, and their optical and sensing performances have been analyzed using the three-dimensional finite-difference time-domain method. It has been shown that the Bragg grating increases the optical confinement factor in the sensing region and, consequently, improves the light–matter interaction and sensitivity. Considering concentrations of 0 to 25% for the NaCl dissolved in the deionized water, the enhanced sensitivity and FOM of the SWG-SMDR sensor with the miniaturized optimal geometrical dimensions are 163.77 nm RIU−1 and 10.81 RIU−1, respectively. This compact optical sensor enhances the sensitivity and FOM by combining effects of the Bragg grating and suspension configuration in improving the light–matter interaction.
Quasi-local masses and cosmological coupling of black holes and mimickers
Authors: Cadoni Mariano , Murgia Riccardo , Pitzalis Mirko , Sanna Andrea P. 
Published: March 2024

Abstract
Motivated by the recent heated debate on whether the masses of local objects, such as compact stars or black holes (BHs), may be affected by the large-scale, cosmological dynamics, we analyze the conditions under which, in a general relativity framework, such a coupling small/large scales is allowed. We shed light on some controversial arguments, which have been used to rule out the latter possibility. We find that the cosmological coupling occurs whenever the energy of the central objects is quantified by the quasi-local Misner-Sharp mass (MS). Conversely, the decoupling occurs whenever the MS mass is fully equivalent to the (nonlocal) Arnowitt-Deser-Misner (ADM) mass. Consequently, for singular BHs embedded in cosmological backgrounds, like the Schwarzschild-de Sitter or McVittie solutions, we show that there is no cosmological coupling, confirming previous results in the literature. Furthermore, we show that nonsingular compact objects couple to the cosmological background, as quantified by their MS mass. We conclude that observational evidence of cosmological coupling of astrophysical BHs would be the smoking gun of their nonsingular nature.
XENONnT and LUX-ZEPLIN constraints on DSNB-boosted dark matter
Authors: Romeri Valentina De , Majumdar Anirban , Papoulias Dimitrios K. , Srivastava Rahul 
Published: March 2024

Abstract
We consider a scenario in which dark matter particles are accelerated to semi-relativistic velocities through their scattering with the Diffuse Supernova Neutrino Background. Such a subdominant, but more energetic dark matter component can be then detected via its scattering on the electrons and nucleons inside direct detection experiments. This opens up the possibility to probe the sub-GeV mass range, a region of parameter space that is usually not accessible at such facilities. We analyze current data from the XENONnT and LUX-ZEPLIN experiments and we obtain novel constraints on the scattering cross sections of sub-GeV boosted dark matter with both nucleons and electrons. We also highlight the importance of carefully taking into account Earth's attenuation effects as well as the finite nuclear size into the analysis. By comparing our results to other existing constraints, we show that these effects lead to improved and more robust constraints.
Transition layer of the relativisyic strophotron
Authors: Oganesyan K B , Gevorgyan A H , Miakota D , Kopcansky P 
Published: March 2024

Abstract
The Klein–Gordon equation of motion in the transition layer of a free-electron laser of the relativistic strophotron type is studied. The condition of suddenly switching-on interaction is found: a smallness of the transition layer at the entrance compared to the distance traveled by the electron in longitudinal direction in one period of transverse oscillations in strophotron. The results are correspond to the results of classical description. It is shown, that in an electric strophotron, under the assumption of a suddenly switching-on interaction, the transverse energy of an electron at the moment t = 0 undergoes a jump. However, the total energy is conserved, because at the same moment t = 0, the longitudinal energy of the electron has the same jump with opposite sign.
A personalized earbud for non-invasive long-term EEG monitoring
Authors: Zeydabadinezhad Mahmoud , Jowers Jon , Buhl Derek , Cabaniss Brian , Mahmoudi Babak 
Published: March 2024

Abstract

Objective. The primary objective of this study was to evaluate the reliability, comfort, and performance of a custom-fit, non-invasive long-term electrophysiologic headphone, known as Aware Hearable, for the ambulatory recording of brain activities. These recordings play a crucial role in diagnosing neurological disorders such as epilepsy and in studying neural dynamics during daily activities. Approach. The study uses commercial manufacturing processes common to the hearing aid industry, such as 3D scanning, computer-aided design modeling, and 3D printing. These processes enable the creation of the Aware Hearable with a personalized, custom-fit, thereby ensuring complete and consistent contact with the inner surfaces of the ear for high-quality data recordings. Additionally, the study employs a machine learning data analysis approach to validate the recordings produced by Aware Hearable, by comparing them to the gold standard intracranial electroencephalography recordings in epilepsy patients. Main results. The results indicate the potential of Aware Hearable to expedite the diagnosis of epilepsy by enabling extended periods of ambulatory recording. Significance. This offers significant reductions in burden to patients and their families. Furthermore, the device’s utility may extend to a broader spectrum, making it suitable for other applications involving neurophysiological recordings in real-world settings.
Brain connectivity patterns derived from aging-related alterations in dynamic brain functional networks and their potential as features for brain age classification
Authors: Han Hongfang , Jiang Jiuchuan , Gu Lingyun , Gan John Q , Wang Haixian 
Published: March 2024

Abstract

Objective. Recent studies have demonstrated that the analysis of brain functional networks (BFNs) is a powerful tool for exploring brain aging and age-related neurodegenerative diseases. However, investigating the mechanism of brain aging associated with dynamic BFN is still limited. The purpose of this study is to develop a novel scheme to explore brain aging patterns by constructing dynamic BFN using resting-state functional magnetic resonance imaging data. Approach. A dynamic sliding-windowed non-negative block-diagonal representation (dNBDR) method is proposed for constructing dynamic BFN, based on which a collection of dynamic BFN measures are suggested for examining age-related differences at the group level and used as features for brain age classification at the individual level. Results. The experimental results reveal that the dNBDR method is superior to the sliding time window with Pearson correlation method in terms of dynamic network structure quality. Additionally, significant alterations in dynamic BFN structures exist across the human lifespan. Specifically, average node flexibility and integration coefficient increase with age, while the recruitment coefficient shows a decreased trend. The proposed feature extraction scheme based on dynamic BFN achieved the highest accuracy of 78.7% in classifying three brain age groups. Significance. These findings suggest that dynamic BFN measures, dynamic community structure metrics in particular, play an important role in quantitatively assessing brain aging.
Effect of Binder Content on Properties of Cordierite-Mullite Porous Ceramics
Authors: Dai Xinchao , Xue RiDong , Qiu Shuang , Deng Xiangyun 
Published: March 2024

Abstract
In this paper, 70-80 mesh SiC particles were used as the base, and 2.5%MgO was added on the basis of quartz, kaolin and potassium feldspar as the binder. Meanwhile, graphite and activated carbon were added as pore-making agents for SiC porous ceramic supports. At the same time, the amount of binder added was changed under the condition of keeping SiC: pore-making agent 8:1 unchanged. The effects of binder content on flexural strength, filtration pressure drop and porosity of porous SiC ceramics were investigated. The results indicated that the comprehensive properties of SiC porous ceramics can be improved by adding proper amount of MgO. When the content of MgO in the binder was controlled at 2.5% and the amount of binder was 6%, the comprehensive performance of the sample was the best under the conditions of 1300 °C, holding time for 90 minutes and forming pressure of 4/10MPa, respectively. In this case, the flexural strength was 48mpa, the porosity was 25% and the filtration pressure drop was good.
Research on the Material Performance and Forming Process of Lunar Regolith Simulant
Authors: Zuo Yang , Shao Heng , Bao Charun , Yang Shaobo , Qi Junfeng , Liu Minying , Zhang Daobo , Feng Peng 
Published: March 2024

Abstract
Establishing a safe and sustainable lunar base on the moon is the foundation for human exploration and development activities. Due to the high transportation costs of the Earth Moon space, a large amount of construction materials are difficult to obtain from Earth. Therefore, how to utilize lunar resources for in-situ construction on the lunar surface has become the key challenge for the construction and operation of lunar base. Faced with special lunar simulant materials and extreme lunar environments, lunar construction faces a series of problems and challenges. This article conducted research on lunar regolith simulant and forming process, providing guidance for lunar surface construction.