bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoluminescence measurement of ruby excited by duty ratio-controlled pulse light-emitting diodes (LED) light source
Authors: Hitomi Ami , Katsumata Toru , Aizawa Hiroaki 
Published: May 2024

Photoluminescence (PL) spectra from ruby were obtained using a highly stable LED light source, employing pulse width modulation technique for excitation. The temporal variation in PL intensity caused by the increasing temperature of the LED used for excitation can be mitigated by adjusting the duty ratio (%) of the pulsed LED light to below 10% for cooling the LED. Stable PL spectra measurements were achieved with a duty ratio of less than 10% using a duty ratio-controlled pulsed LED light source, as temperature fluctuations in LED light intensity are minimized at duty ratios less than 10%. Furthermore, fluctuations in the measured PL intensity were diminished by setting the frequency of the pulsed LED light source to greater than 1 kHz. This method enables more reliable, cost-effective, and stable PL measurements for material characterization in semiconductors, photonics, and nanotechnology.
Exogenous zinc application mitigates negative effects of salinity on barley (Hordeum vulgare) growth by improving root ionic homeostasis
Authors: Khan Waleed Amjad , Penrose Beth , Yun Ping , Zhou Meixue , Shabala Sergey 
Published: May 2024

Detrimental effects of salinity could be mitigated by exogenous zinc (Zn) application; however, the mechanisms underlying this amelioration are poorly understood. This study demonstrated the interaction between Zn and salinity by measuring plant biomass, photosynthetic performance, ion concentrations, ROS accumulation, antioxidant activity and electrophysiological parameters in barley (Hordeum vulgare L.). Salinity stress (200 mM NaCl for 3 weeks) resulted in a massive reduction in plant biomass; however, both fresh and dry weight of shoots were increased by ~30% with adequate Zn supply. Zinc supplementation also maintained K+ and Na+ homeostasis and prevented H2O2 toxicity under salinity stress. Furthermore, exposure to 10 mM H2O2 resulted in massive K+ efflux from root epidermal cells in both the elongation and mature root zones, and pre-treating roots with Zn reduced ROS-induced K+ efflux from the roots by 3–4-fold. Similar results were observed for Ca2+. The observed effects may be causally related to more efficient regulation of cation-permeable non-selective channels involved in the transport and sequestration of Na+, K+ and Ca2+ in various cellular compartments and tissues. This study provides valuable insights into Zn protective functions in plants and encourages the use of Zn fertilisers in barley crops grown on salt-affected soils.
Melatonin administration during the first half of pregnancy improves physiological response and reproductive performance of rabbits under heat stress conditions
Authors: Hashem Nesrein M. , Abdelnaby Elshymaa A. , Madkour Mahmoud , El-Sherbiny Hossam R. 
Published: May 2024

Context Melatonin may have a heat-stress-alleviating role during pregnancy. Aims To investigate the effects of melatonin administration during the first half of pregnancy on heat-tolerance capacity and pregnancy outputs of naturally heat-stressed rabbits. Methods Forty female rabbits were stratified equally into two experimental groups and daily received 1 mg melatonin/kg body weight or not (control) for 15 consecutive days post-insemination. Heat tolerance indices, hormone profile, ovarian structures, and fetal loss were determined. Key results Treatment with melatonin significantly decreased respiration rate and rectal temperature, improved concentrations of nitric oxide, and tended to decrease malondialdehyde concentrations (P = 0.064) compared to control. Melatonin treatment significantly increased concentrations of high-density lipoprotein, oestradiol, and progesterone compared to control. No significant differences in the numbers of visible ovarian follicles, corpora lutea, and total implantation sites on day 18 of pregnancy were observed between experimental groups. However, melatonin treatment significantly reduced the number of absorbed implantation sites and significantly improved amniotic fluid volume and conception rate compared to control. Conclusions Melatonin administration during the first half of pregnancy can improve reproductive performance of heat-stressed female rabbits. Implications Melatonin can improve fetal survivability via improving heat-tolerance capacity of does and steroidogenesis.
Time Transfer in a 1839-km Telecommunication Fiber Link Demonstrating a Picosecond-Scale Stability
Authors: Guo 郭 Xinxing 新兴 , Hou 侯 Bing’an 丙安 , Liu 刘 Bo 博 , Yang 杨 Fan 凡 , Kong 孔 Weicheng 维成 , Liu 刘 Tao 涛 , Dong 董 Ruifang 瑞芳 , Zhang 张 Shougang 首刚 
Published: May 2024

Abstract
An implementation of high-precision time transfer over a 1839-km field fiber loop back link between two provincial capitals of China, Xi’an and Taiyuan, is reported. Time transfer stabilities of 6.5 ps at averaging time of 1 s and 4.6 ps at 40000 s were achieved. The uncertainty for the time transfer system was evaluated, showing a budget of 56.2 ps. These results stand for a significant milestone in achieving high-precision time transfer over a field fiber link spanning thousands of kilometers, signifying a record-breaking achievement for the real-field time transfer in both stability and distance, which paves the way for constructing the nationwide high-precision time service via fiber network.
Echoes of social experience: tracing the link between a sense of belonging in school physics classes and physics students’ persistence in higher education
Authors: Feser Markus Sebastian , Rabe Thorid , Haak Inka 
Published: May 2024

Abstract
The present study investigates on an exploratory level the extent to which the sense of belonging that university physics students experienced in their physics classes in secondary school impacts their intention to drop out or alter their course of study in higher education. Analysing data collected between April and June 2022 among first-year physics students at 20 German universities (N = 263), we find a significant and negative effect on the part of participants’ (remembered) sense of belonging in school physics classes on their intention to drop out or change their studies. Parallel mediation analysis further reveals that this effect is fully mediated by students’ current sense of belonging to physics and their university. Notably, the indirect effect via participants’ current sense of belonging to physics is approximately four times as high as the indirect effect via university belonging. These results emphasise the importance of social embeddedness in early physics experiences on students’ academic development in higher education. Limitations of these results as well as implications regarding a potential improvement of persistence and satisfaction within physics-related higher-education programs are outlined at the end of this paper.
Investigation of stabilization and survival of skyrmion vortices in the presence of magnetic field disorder in two-dimensional lattices: a case study for Janus dichalcogenides
Authors: Yüksel Yusuf 
Published: May 2024

Abstract
Due to the lack of inversion symmetry, very large Dzyaloshinskii–Moriya interaction (DMI) has been reported for a series of Janus monolayers of manganese dichalcogenides within the framework of first-principles calculations (Liang et al 2020 Phys. Rev. B 101 184401). However, from the viewpoint of potential applications, the current ongoing research mainly focuses on the magnetism in pristine two-dimensional (2D) materials exhibiting non-zero DMI, and the effects of disorder in such systems remain an open problem since the influence of randomness may create some drastic effects on the magnetism of low dimensional systems. Here, we present Monte Carlo simulation results regarding the magnetic properties of a 2D manganese based Janus dichalcogenide material

MnSTe

in the presence of quenched random magnetic fields where the local field variables have been sampled from a Gaussian distribution. For the selected benchmark material, it has been found that the magnetic skyrmion vortexes emerging at (10 K, 3 T) may survive in the presence of weak and moderate quenched randomness, which is important from the viewpoint of technological applications. In both the pristine and random field cases, the stabilization of magnetic skyrmions are achieved by the major contribution of the ferromagnetic exchange energy to the total energy of the system, and the materials exhibiting large DMI/exchange ratios may exhibit resilient magnetic skyrmion vortexes in the presence of weak and moderate amount of randomness.
Design and analysis of mode-matched decoupled mass MEMS gyroscope with improved thermal stability
Authors: Bashir Uzair , Bazaz Shafaat Ahmed , Saleem Muhammad Mubasher , Shakoor Rana Iqtidar , Tariq Muhammad Owais , Kumar Pirbhat 
Published: May 2024

Abstract
This paper presents an efficient design approach for microelectromechanical systems (MEMS) gyroscope considering the design constraint of MEMSCAP’s Silicon-on-Insulator Multi-User MEMS Processes (SOIMUMPs). A design for a decoupled mass MEMS resonant gyroscope with tuning electrodes is presented to minimize cross-axis coupling and optimize the gyroscope’s performance. The device features a size of

1.8

×
2.772

m

m

2

. A decoupled mass MEMS gyroscope has been designed using a novel mechanical beam configuration that optimizes the structural design to reduce unwanted interactions between drive and sense axes motions. Mode order has been achieved by obtaining the first two modes as drive and sense modes at 9946.3 Hz and 10 202.7 Hz, respectively. Parallel plate electrostatic tuning electrodes have been added to adjust and match the drive and sense modes at the resonant frequencies of 9946 Hz. This mode matching is crucial for optimizing gyroscope performance, accuracy, and sensitivity. The effects of temperature variation on the performance of the designed decoupled mass MEMS gyroscope have been investigated, particularly in terms of its mode-matched operation achieved using tuning electrodes. Finite element method (FEM) simulations were conducted, demonstrating that thermal stability was achieved, and mode-matched operation was maintained within the temperature range of −40 °C to 80 °C. The gyroscope exhibits enhanced performance compared to existing MEMS gyroscopes under mode-matched conditions, featuring a lower temperature coefficient of frequency (TCF) at 0.0415 Hz °C−1 in the drive mode and 0.0165 Hz °C−1 in the sense mode. FEM analysis for the fabrication process tolerances has been done, where MEMS gyroscope’s resonant frequencies, output capacitance, output displacement, and sense mode quality factor have shown negligible changes to fabrication process tolerances. Transient analysis was conducted using CoventorWare MEMS+ 3D schematic, which was integrated with MATLAB Simulink to measure the MEMS gyroscope’s output response, which corresponded with the varying input angular velocity signal.
An infinite dimensional KAM theorem with normal degeneracy
Authors: Du Jiayin , Xu Lu , Li Yong 
Published: May 2024

Abstract
In this paper, we consider a classical Hamiltonian normal form with degeneracy in the normal direction. In previous results, one needs to assume that the perturbation satisfies certain non-degenerate conditions in order to remove the degeneracy in the normal form. Instead of that, we introduce a topological degree condition and a weak convexity condition, which are easy to verify, and we prove the persistence of lower dimensional tori without any restriction on perturbation but only smallness and analyticity.
Transformer-CNN hybrid network for improving PET time of flight prediction
Authors: Feng Xuhui , Muhashi Amanjule , Onishi Yuya , Ota Ryosuke , Liu Huafeng 
Published: May 2024

Abstract

Objective. In positron emission tomography (PET) reconstruction, the integration of time-of-flight (TOF) information, known as TOF-PET, has been a major research focus. Compared to traditional reconstruction methods, the introduction of TOF enhances the signal-to-noise ratio of images. Precision in TOF is measured by full width at half maximum (FWHM) and the offset from ground truth, referred to as coincidence time resolution (CTR) and bias. Approach. This study proposes a network combining transformer and convolutional neural network (CNN) to utilize TOF information from detector waveforms, using event waveform pairs as inputs. This approach integrates the global self-attention mechanism of Transformer, which focuses on temporal relationships, with the local receptive field of CNN. The combination of global and local information allows the network to assign greater weight to the rising edges of waveforms, thereby extracting valuable temporal information for precise TOF predictions. Experiments were conducted using lutetium yttrium oxyorthosilicate (LYSO) scintillators and silicon photomultiplier (SiPM) detectors. The network was trained and tested using the waveform datasets after cropping. Main results. Compared to the constant fraction discriminator (CFD), CNN, CNN with attention, long short-term memory (LSTM) and Transformer, our network achieved an average CTR of 189 ps, reducing it by 82 ps (more than 30%), 13 ps (6.4%), 12 ps (6.0%), 16 ps (7.8%) and 9 ps (4.6%), respectively. Additionally, a reduction of 10.3, 8.7, 6.7 and 4 ps in average bias was achieved compared to CNN, CNN with attention, LSTM and Transformer. Significance. This work demonstrates the potential of applying the Transformer for PET TOF estimation using real experimental data. Through the integration of both CNN and Transformer with local and global attention, it achieves optimal performance, thereby presenting a novel direction for future research in this field.
Enhancement of OCT en face images by unsupervised deep learning
Authors: Yuan Zhuoqun , Yang Di , Zhao Jingzhu , Liang Yanmei 
Published: May 2024

Abstract

Objective. The quality of optical coherence tomography (OCT) en face images is crucial for clinical visualization of early disease. As a three dimensional and coherent imaging, defocus and speckle noise are inevitable, which seriously affect evaluation of microstructure of bio-samples in OCT images. The deep learning has demonstrated great potential in OCT refocusing and denoising, but it is limited by the difficulty of sufficient paired training data. This work aims to develop an unsupervised method to enhance the quality of OCT en face images. Approach. We proposed an unsupervised deep learning-based pipeline. The unregistered defocused conventional OCT images and focused speckle-free OCT images were collected by a home-made speckle modulating OCT system to construct the dataset. The image enhancement model was trained with the cycle training strategy. Finally, the speckle noise and defocus were both effectively improved. Main results. The experimental results on complex bio-samples indicated that the proposed method is effective and generalized in enhancing the quality of OCT en face images. Significance. The proposed unsupervised deep learning method helps to reduce the complexity of data construction, which is conducive to practical applications in OCT bio-sample imaging.
Power deposition in the He bath induced by the Z gradient coil in the 11.7 T Iseult magnet: theory versus measurements
Authors: Aubert G , Guihard Q , Dubois O , Lannou H , Juster F-P , Belorgey J , Nunio F , Amadon A , Bonnelye C , Gras V , Le Ster C , Mauconduit F , Vignaud A , Quettier L , Boulant N 
Published: May 2024

Abstract
Gradient-magnet interactions increase with higher field magnets and stronger gradient coils. Perhaps the most sensitive aspect is magnet quench, which can be induced by a loss of superconductivity of the main coil caused by a rise of the temperature of the He bath with gradient activity. Predicting power depositions thereby can be a very valuable tool to avoid dangerous frequency zones but also eventually correct design flaws. In this work, we report model predictions compared to measurements of power deposition in the He bath of the Iseult 11.7 T magnet for the Z gradient coil axis.
Implicit particle-in-cell development for ion source plasmas
Authors: Savard N. , Fubiani G. , Baartman R. , Dehnel M. 
Published: May 2024

Abstract
Particle-in-Cell (PIC) codes used to study plasma dynamics within ion sources typically use an explicit scheme. These methods can be slow when simulating regions of high electron density in ion sources, which require resolving the Debye length in space and the plasma frequency in time. Recent developments on fully-implicit PIC models in curvilinear geometries have shown that these spatial/time scales can be significantly decreased/increased respectively, allowing for notable speed-ups in simulation time, and thus making it a potential tool for studying the physics of ion sources. For this purpose, a charge and energy conserving implicit PIC code has been developed in 1D to determine its potential for simulating bounded plasmas. In this paper, we use this model to simulate a 1D benchmark of a bounded plasma with fixed plasma density and electron/ion temperatures. The results are shown to compare well to the benchmark and to the results using an explicit PIC code. It is shown that the total amount of macro-particles used in the simulation is a better figure of merit for accurate results than the standard particles per cell used in literature. Significant speed-ups in computation time can be achieved for high plasma densities if the accuracy requirements are relaxed. In this case, we demonstrate the ability of the implicit PIC code to speed-up simulation time by nearly a factor of 12 compared to explicit PIC.
Initial Experimental Results of Producing Multicharged Ions Efficiently by Lower Hybrid Resonance Heating with Exciting Helicon Waves on Electron Cyclotron Resonance Ion Source
Authors: Kato Yushi , Harisaki Shuhei , Kubo Wataru , Iwahara Kouki , Fujimura Yushi 
Published: May 2024

Abstract
Based on experimental results, we considered the accessibility conditions for wave propagation in the magnetized plasma in an electron cyclotron resonance (ECR) ion source (ECRIS), and proposed introducing electromagnetic waves with frequencies lower than those of ECR. We generate the lower hybrid resonance (LHR) in the ECRIS by the electric field of the extra-ordinary mode (X-mode) on the helicon wave which additionally heat the electrons, and then it was conducted to improve the efficiency of multicharged ion generation successfully in over density condition. The electron energy distribution function obtained by the probe measurement shows an increase in the high-energy region in the corresponding LHR region. In this paper, for the first time we describe the initial experimental results on enhanced production of multicharged ions by the LHR of the low-frequency RF electromagnetic waves into the ECRIS.
Simple 3D PIC Analysis for Beam Phase Space Oscillation in RF Driven Negative Hydrogen Ion Source
Authors: Shibata T , Shinto K , Nakano H , Hoshino K , Miyamoto K , Ohkoshi K , Nanmo K , Ikegami K , Kawai I , Oguri H , Wada M 
Published: May 2024

Abstract
Temporal oscillation of the negative hydrogen ion (H−) beam in the Radio Frequency (RF) ion source is investigated by a simple 3D3V Particle-In-Cell (PIC) model. The model solves electron, proton, and H− transport processes in the extraction region. The calculation domain is from the vicinity of the beam aperture to the ground electrode. To understand the relation between the plasma density oscillation and the extracted H− beam characteristics, the input electron and proton fluxes from the driver region are varied parametrically with the fundamental J-PARC RF frequency (2 MHz). The numerical results give an idea of the main physical processes between the oscillations of the plasma parameters and the extracted H− ion trajectories depending on the plasma meniscus shape in the different RF phases.
Novel modelling of metal atoms diffusion and ion transport in ECR plasma relevant to ion sources and in-plasma nuclear physics studies
Authors: Pidatella A , Galatà A , Mishra B , Naselli E , Celona L , Lang R , Maimone F , Mauro G S , Santonocito D , Torrisi G , Mascali D 
Published: May 2024

Abstract
Metals can be injected into electron cyclotron resonance ion sources (ECRIS) via different techniques, among which resistive ovens are used to vaporize neutral materials, later captured by the energetic plasma that will step-wise ionize them, hence giving multiply charged ion beams for accelerators. Recently, PANDORA, a novel ECR plasma trap, has been conceived to perform interdisciplinary research spanning from nuclear physics to astrophysics, where in-plasma high charge states of metallic species are demanded. However, a full knowledge on the vaporization method and on the coupling of neutral atoms with plasma and its overall dynamics is still not available. Simulations, hence, are of fundamental relevance to improve the overall efficiency, reduce consumption of rare expensive isotopes, and to improve the ion source performance. We present a numerical study about metallic species suitable for oven injection in ECRIS, focusing on metals diffusion, transport, and wall deposition under molecular flow regime. We studied the metal dynamics with and without plasma. Results underline the plasma role on a space-dependent conversion yield, reflecting the strongly inhomogeneous ECR plasma. The plasma and its parameters have been modelled using an established self-consistent particle-in-cell model. The numerical tool is conceived for the PANDORA plasma trap but can be extended to other ECR plasmas and traps. As test cases we studied the 134Cs and 48Ca radioisotopes, as metals of interest for the modern nuclear physics. A focus is given on the β-decaying 134Cs, as an application case for PANDORA, providing quantitative estimates of the γ-detection signal-poisoning effect by neutral metals deposition at the chamber wall.
Installation and first results of a 1.1 kW TWT system for the AECR-U based ion source at UMCG-Partrec
Authors: Kremers H R , Jones B N , Brandenburg S , Gerbershagen A 
Published: May 2024

Abstract
To meet the demand for intense highly charged stable ion beams for medical and nuclear physics a traveling-wave-tube (TWT) based RF generator has been installed and is in commissioning at the Advanced Electron Cyclotron Resonance Upgrade (AECR-U) ion source at the UMCG-PAR-TREC facility. The generator comprises 2 x 750W in-phase combining TWT RF generators with an output frequency range of 12.75-14.5 GHz. Frequency scanning routines have been incorporated in the control software which makes it possible to identify intense and stable ion-beam regimes within the plasma-heating frequency domain. The new RF generator replaces a 14.1 GHz fixed frequency klystron. In this paper we present the setup, the scanning methodology, the first measurements, and discuss the frequency scans measured from a helium and a xenon beam. These results improve the stability and increase the beam intensity at the UMCG-PARTREC facility.