bluuebunny/crossref_metadata_2025 huggingface dataset:
Cognitive and emotional factors related to COVID-19 among high-risk ethnically diverse adults at the onset of the New York City outbreak: A cross-sectional survey
Authors: Kukafka Rita , Millery Mari , Pan Samuel , Silverman Thomas B. , Zhang Tianmai , McGuinness Julia E. , Crew Katherine D. , Aguirre Alejandra N.
Published: May 2023

A cross-sectional survey was conducted among high-risk, racially/ethnically diverse adults at the point in time when New York City (NYC) became the COVID-19 pandemic’s global epicenter. The study objective was to assess the threat and coping appraisals (cognitive factors known to correspond with people’s willingness to adopt behaviorally focused interventions) and levels of distress, anxiety, and intolerance for uncertainty (emotional factors). Survey respondents were recruited in April 2020 using an online survey with unpaid recruitment on the GetHealthyHeights.org community-oriented website. We also recruited participants that engaged in previous research studies to gain survey responses from community members at higher risk for COVID-19 complications due to comorbidities compared to the general population. Analysis was performed to test for differences in survey responses by comorbidities, age, race, ethnicity, and employment status. Results show that the devastating effects of the pandemic appear to have uniquely impacted minority respondents, who reported significantly higher levels of anxiety and were significantly more likely to report having little control over whether they will get COVID-19 compared with White/non-Hispanic respondents. Minority respondents also had significantly higher mean scores on the behaviorally focused dimension of the intolerance of uncertainty (IU) scale, which measures avoidance and paralysis in the face of uncertainty. In multivariate analysis, IU predicted anxiety levels, and this association was not mediated by cognitive factors (threat and coping appraisals). By conducting this survey early in the pandemic, our study uniquely evaluated cognitive and emotional factors among a racially/ethnically diverse group of NYC residents during the height of the COVID-19 pandemic. Our findings suggest the need to acknowledge the disparities that appear to exist in pandemic response and for culturally tailored messaging and interventions. Few studies have reported differences by race and ethnicity during pandemic exposure. Therefore, further research on factors that may influence pandemic response among minority populations is needed.
Cavitation generated by vibrating quartz tuning fork in concentrated 3He–4He mixture
Authors: Chagovets V. K. , Kapuza S. S. , Sokolov S. S. , Chagovets T. V.
Published: May 2023

The state of the problem of cavitation in superfluid helium and the content of previous works on this topic are analyzed. The transition between turbulent flow and cavitation under oscillations of a quartz tuning fork in a normal and superfluid isotopic mixture containing 15% of 3He in the temperature range of 0.5–3 K is studied experimentally. The temperature dependences of the critical velocity for the cavitation onset and the critical transition excitation force are obtained. We compare the results of our measurements with the data obtained by other groups. The results of measurements with tuning forks in restricted and unrestricted geometries suggest that the presence of acoustic emission facilitates the conditions for the onset of cavitation and indirectly confirms the role of vortex lines. A comparison of the temperature dependences of the critical velocity of cavitation onset in pure 4He and a concentrated 3He–4He mixture did not give an unambiguous answer to the reason for the sharp increase of this velocity, at the transition to the superfluid state, and the contributions of both thermal effects and the 3He impurities to the velocity increase.
Decarbonization technologies for reducing maritime pollution
Authors: Lange Katherine De
Published: May 2023

Emission reduction potential and economic feasibility of maritime shipping technologies.
Multiple mixed interior and boundary peaks synchronized solutions for nonlinear coupled elliptic systems
Authors: Tang Zhongwei , Wang Lushun , Xie Huafei
Published: May 2023

This paper is devoted to a class of singularly perturbed nonlinear Schrödinger systems defined on a smooth bounded domain in RN(N=2,3). We use the Lyapunov–Schmidt reduction method to construct synchronized vector solutions with multiple spikes both on the boundary and in the interior of the domain. For each vector solution that has been constructed, we point out that the interior spikes locate near sphere packing points in the domain, and the boundary spikes locate near the critical points of the mean curvature function related to the boundary of the domain.
An alternative justification for the stationary assumption made by many reduced models for nonlocal electron heat flow in plasmas
Authors: Brodrick J. P. , Del Sorbo D. , Ridgers C. P.
Published: May 2023

Nonlocal models are widely used for approximating kinetic effects on electron heat flow in fusion-relevant plasmas. Almost universally, such models have no explicit time dependence and are designed to make heat flow predictions based directly on instantaneous profiles of macroscopic plasma parameters. While this is usually justified by the claim that transient effects fade before temperature profiles evolve appreciably, a more rigorous justification of the stationarity assumption in terms of kinetic theory is desirable. In this Letter, such a justification is provided by demonstrating that nonstationary effects related to the time dependence of the isotropic part of the electron distribution function vanish up to third order in Chapman–Enskog theory (irrespective of ion charge state or presence of magnetic fields). However, it is found that the electron inertia term (whose appearance in Ohm's law stems from the time derivative of the anisotropic part of the electron distribution function) does have a small but finite third order effect that is most prominent for plasmas with low average ion charges. This Letter additionally provides a convenient analytic inverse for the isotropic part of the Landau electron–electron collision operator.
Dependence of the Gd concentration range for thermally induced magnetization switching on the intrinsic damping
Authors: Liu Donglin , Jiang Caijian , Li Hai , Xu Chudong
Published: May 2023

Ultrafast magnetization switching induced by a single femtosecond laser pulse in the absence of an applied magnetic field has attracted extensive attention due to its great potential for low energy and ultrafast storage applications. However, pulse helicity-independent switching is mainly used for Gd-based materials, and it is now necessary to explore the possibility of further optimization depending on the composition and damping coefficients. For the GdFe alloy with low Gd concentration, we modulate the damping constant for a comparative analysis based on atomic spin simulations. The simulation results show that an appropriate increase in the high damping ratio αFe/αGd not only helps to extend the pulse fluence range for switching but also reduces the minimum Gd concentration requirement for transient ferromagnetic-like state. The results show that the pulse fluence threshold of switching at low Gd concentration is more sensitive to the damping ratio αFe/αGd. On the contrary, modulating the damping ratio αFe/αGd at high Gd concentrations almost does not cause the shift of pulse fluence threshold. The lower Gd concentration for thermally induced magnetization switching is expected to be unlocked by the engineering of element-specific damping.
Growth and passivation of individual carbon nanoparticles by C2H2 addition at high temperatures: Dependence of growth rate and evolution on material and size
Authors: Lau Chris Y. , Rodriguez Daniel J. , Friese Abigail M. , Anderson Scott L.
Published: May 2023

Absolute kinetics for reactions of C2H2 with a series of ∼60 individual carbon nanoparticles (NPs) from graphite, graphene, graphene oxide, carbon black, diamond, and nano-onion feedstocks were measured for temperatures (TNP) ranging from 1200 to 1700 K. All the NPs were observed to gain mass by carbon addition under conditions that varied with feedstock but with large variations in initial growth rate. Long reaction periods were studied to allow the evolution of growth rates over time to be observed. Diamond NPs were found to passivate against C2H2 addition if heated above ∼1400 K, and the highly variable initial reactivity for carbon nano-onions was found to depend on the presence of non-onion-structure surface carbon. For graphitic and carbon black NPs, three distinct growth modes were observed, correlated with the initial NP mass (Minitial). Smallest graphitic and carbon black NPs, with masses <∼25 MDa, initially grew rapidly but also passivated quickly after adding <4% of Minitial. NPs in the 20–50 MDa range also passivated but only after multiple waves of fast growth separated by periods of low reactivity, with up to ∼11% total mass gain before passivation. The largest carbon black and graphitic NPs, with Minitial >50 MDa, grew rapidly and continuously, adding up to ∼300% of Minitial with no sign of rate slowing as long as C2H2 was present. The efficiencies for C2H2 addition and etching by O2 are strongly correlated, but the correlation changes as the NPs passivate. Growth and passivation mechanisms are discussed.
An entropy-based method to measure phase-locking between LFP and spikes
Authors: Dang Xing-Yan , Xu Han-Ting , Bao Xin-Yu , Xie Yun-Yong , Zhu Jing-Ning , Zhang Xiao-Yang , Huang Xiao-Lin
Published: May 2023

Phase-locking between local field potential and spikes has been widely investigated through neurophysiological analysis. Two indices most frequently adopted traditionally include the mean resultant length and p of the Rayleigh test. However, the traditional method is found less reliable for cases with substantial sample sizes or with bimodal distribution. In this article, K we propose an entropy-based method to detect and measure phase-locking. Simulation results prove that the method can be effectively applied to cases with a relatively large sample size and it can effectively detect phase-locking even under bimodal conditions with two peaks of opposite phases. Furthermore, we propose thresholds to help measure the intensity of spike field phase-locking. We also apply the proposed method to our experimental data and find phase locking with two opposite phases, which would be left out in traditional phase-locking analysis.
Enhanced adsorption and non-linear optical properties of DNA-CTAB functionalized mesoporous silica nanoparticles and their influence on enhancement of photoluminescence of Rhodamine 6G dye
Authors: Bhagyasree G. S. , Reena V. N. , Abith M. , Sabari Girisun T. C. , Nithyaja B.
Published: May 2023

We report a novel template method for synthesizing silica nanoparticles that are mesoporous as well as biocompatible. The mesoporous silica nanoparticles were synthesized using the Stober process and peptization method. We have used surface-modified deoxyribonucleic acid (DNA) with cetyl trimethyl ammonium bromide as a capping agent. The obtained silica particles were analyzed using x-ray diffraction, UV–vis spectroscopy, the Brunauer–Emmet–Teller method, scanning electron microscopy, and the open aperture Z-scan technique. The characterization results indicated that the DNA polymer’s presence influenced the formation of the silica particles. The silica particles are mesoporous, nanosized, and good adsorbent and also show enhanced non-linear optical properties when compared with existing silica nanoparticles. The solubility of the silica nanoparticles was also verified in dimethyl sulfoxide (DMSO). We have verified that the enhanced mesoporous surface area and reduced porous size of the silica nanoparticles influenced the photoluminescence of Rhodamine 6G dye in DMSO. This can be applied to lower the lasing threshold of the gain medium in lasing applications. Hence, the obtained silica nanoparticles have a variety of applications such that they can be used as adsorbents of nanosized particles, which is applicable for drug delivery purposes, bioimaging, catalytic activities, doping surface for thin film making, biosensing applications, and improvement of material quality for solar devices. The non-linear optical property of the mesoporous silica nanoparticles can be used for optical limiting applications in photonic devices.
Suppressing parametric instabilities in direct-drive inertial-confinement-fusion plasmas using broadband laser light
Authors: Bates J. W. , Follett R. K. , Shaw J. G. , Obenschain S. P. , Myatt J. F. , Weaver J. L. , Wolford M. F. , Kehne D. M. , Myers M. C. , Kessler T. J.
Published: May 2023

It has long been recognized that broadband laser light has the potential to control parametric instabilities in inertial-confinement-fusion (ICF) plasmas. Here, we use results from laser-plasma-interaction simulations to estimate the bandwidth requirements for mitigating the three predominant classes of instabilities in direct-drive ICF implosions: cross-beam energy transfer (CBET), two-plasmon decay (TPD), and stimulated Raman scattering (SRS). We find that for frequency-tripled, Nd:glass laser light, a bandwidth of 8.5 THz can significantly increase laser absorption by suppressing CBET, while ∼13 THz is needed to mitigate absolute TPD and SRS on an ignition-scale platform. None of the glass lasers used in contemporary ICF experiments, however, possess a bandwidth greater than 1 THz and reaching larger values requires the use of an auxiliary broadening technique such as optical parametric amplification or stimulated-rotational-Raman scattering. An arguably superior approach is the adoption of an argon-fluoride (ArF) laser as an ICF driver. Besides having a broad bandwidth of ∼10 THz, the ArF laser also possesses the shortest wavelength (193 nm) that can scale to the high energy/power required for ICF—a feature that helps to mitigate parametric instabilities even further. We show that these native properties of ArF laser light are sufficient to eliminate nearly all CBET scattering in a direct-drive target and also raise absolute TPD and SRS thresholds well above those for broadband glass lasers. The effective control of parametric instabilities with broad bandwidth is potentially a “game changer” in ICF because it would enable higher laser intensities and ablation pressures in future target designs.
Laboratory reproduction of grey triggerfish (Balistes capriscus)
Authors: Cardoso Leonardo Demier , Souza André Batista de , Mattos Douglas da Cruz , Polese Marcelo Fanttini , Bassul Lucas Areias , Aride Paulo Henrique Rocha , França Marlon Carlos , Lavander Henrique David
Published: May 2023

Context Balistes capriscus is relevant for fishing worldwide, but there is no consistent information on the maintenance of the species in a captive environment. Aims Develop protocols for the reproduction of the species in aquaculture systems, contributing to the maintenance of the supply in the commerce through captive breeding. Methods A Balistes capriscus couple was selected on the basis of behavioural observations. Nutritional and environmental stimuli were invested in obtaining natural spawning. After reproduction, the larvae were regularly observed under an microscope to monitor the ontogenic development. In larviculture, feeds based on Brachionus plicatilis (10 mL−1) and Nannochloropsis oculata (150 000 cells mL−1) and pate formulated with Artemia salina, Nannochloropsis oculata, sardines and commercial feed were evaluated. Key results The eggs had a diameter of 667.5 μm (±21.66) and formed a mass adhered to the substrate. Newly hatched larvae had a total length of 1653.63 μm (±213.97). The first food intake was evidenced 72 h after hatching; however, larvae did not survive more than 6 days. Conclusions The reproduction in laboratory of the species is viable; however, larviculture remains a limiting factor. Implications The success in captive breeding is essential for the introduction of B. capriscus in aquaculture, and for the conservation of the species.
The impact of leptin on sperm
Authors: Almabhouh Fayez A. , Singh Harbindar Jeet
Published: May 2023

Despite its important role in numerous physiological functions, including regulation of appetite and body weight, immune function and normal sexual maturation, raised leptin levels could result in significant damaging effects on sperm. The adverse effects of leptin on the male reproductive system result from its direct actions on the reproductive organs and cells instead of the hypothalamus–pituitary–gonadal axis. Binding of leptin to the receptors in the seminiferous tubular cells of the testes increases free radical production and decreases the gene expression and activity of endogenous enzymatic antioxidants. These effects are mediated via the PI3K pathway. The resultant oxidative stress causes significant damage to the seminiferous tubular cells, germ cells and sperm DNA leading to apoptosis, increased sperm DNA fragmentation, decreased sperm count, increased fraction of sperm with abnormal morphology, and decreased seminiferous tubular height and diameter. This review summarises the evidence in the literature on the adverse effects of leptin on sperm, which could underlie the often-reported sperm abnormalities in obese hyperleptinaemic infertile males. Although leptin is necessary for normal reproductive function, its raised levels could be pathologic. There is, therefore, a need to identify the cut-off level in the serum and seminal fluid above which leptin becomes pathological for better management of leptin associated adverse effects on male reproductive function.
Slowing Metaphor Down
Authors: Steen Gerard J.
Published: May 2023

If thinking can be fast or slow, metaphorical thinking can be fast and slow too. But metaphorical thinking does not occur as often and in the ways that many metaphor scholars today think. Slow metaphorical thinking does mean, however, that we can exert more control over metaphor than has previously been acknowledged. We can even offer resistance to metaphor.

Deliberate Metaphor Theory (DMT) claims that there is an essential processing difference between non-deliberate and deliberate metaphor use which can explain all this. This book is the first full account of the DMT model for metaphor comprehension. It presents explicit conceptualization and formal operationalization, and is based on a well-known cognitive-psychological model for all utterance comprehension in discourse. The original three-dimensional model of DMT is here refined into a four-dimensional model, which reveals new research questions and discoveries about the use of metaphor.

The book brings together numerous cognitive-scientific insights into metaphor. It has a high degree of interdisciplinary accessibility to all students of metaphor, whether master students, PhDs, post docs, or established academics.
Derived verbs and future-conditional stem regularization in
written Spanish in synchrony and diachrony
Authors: Graham Lamar A.
Published: May 2023

Spanish verbs derived via prefixation
prescriptively retain the morphological complexity of their root
verbs. However, some verbs derived from decir and
hacer show allomorphic variation in the future
and conditional, which is documented by the RAE for
decir but not at all for
hacer. The results of this study of historical
variation suggest decreased morphological transparency of some verbs
but not of others. Verbs derived from hacer
continue to resist regularization, with the notable exception of
satisfacer. The set of
decir-derived verbs is much more complex in its
tendencies. This may be attributable to either (a) perceived opacity
of contradecir or (b) increased analogical pressure
from maldecir and bendecir which
are completely regularized in modern usage. The presence of
regularized bendecir and its possible effects on
etymologically related verbs contrasts with the resistance of
regularization of hacer-derived verbs and the
consequent absence of analogical pressure.
Real and apparent (time) changes in Yucatan Spanish
Authors: Michnowicz Jim
Published: May 2023

Yucatan Spanish (YS) is a regional dialect that
shows a variety of language contact features due to sustained close contact with an indigenous language, Yucatec Maya. Previous
research has indicated that YS is undergoing rapid standardization
toward Central Mexican norms for a variety of potential contact
features (Michnowicz,
2015). Among these features is the realization of
intervocalic /bdg/ as stops rather than approximants, with younger
speakers producing more normative approximant realizations (Michnowicz, 2009, 2011). The present study
builds on previous research by analyzing newly-collected data,
giving a real-time dimension to the study of YS /bdg/. Results
confirm the findings of previous studies in apparent-time, and
provide additional detail on how young speakers are moving away from
traditional YS forms.
Individual differences do not affect trill variation by advanced
learners of Spanish
Authors: Zahler Sara L. , Daidone Danielle
Published: May 2023

The current study analyzed whether variation in
trill pronunciation by advanced learners of Spanish is conditioned
by individual differences in phonological short-term memory,
executive working memory, second language vocabulary
score, and years of study, as well as five linguistic variables. We
found that none of the individual difference variables significantly
affected variation, while surrounding phonetic context and lexical
stress were important predictors of this variation. The findings
suggest that these individual differences do not impact trill
variation by advanced learners, possibly because these factors are
more important at lower levels of proficiency, or because trill
variability is largely impacted by phonetic factors due to the
well-known articulatory difficulty of this sound.
Myoelectric activity and improvements in strength and hypertrophy are unaffected by the ankle position during prone leg curl exercise – a within person randomized trial
Authors: Cadeo Gabriela M. , Fujita Rafael A. , Villalba Marina M. , Silva Nilson R. S. , Júnior Claudinei Iossi , Pearcey Gregory E. P. , Gomes Matheus M.
Published: May 2023

To examine the effect of ankle position (i.e. gastrocnemius muscle length) on training outcomes during leg curl exercise, we recruited untrained and trained healthy adults to participate in two separate experiments. In Experiment 1, we studied the acute influence of ankle position on knee flexor myoelectric (EMG) activity during leg curl exercise in a group of trained and a separate group of untrained adults. In Experiment 2, we studied the effects of ankle position on knee flexors muscle thickness and torque across a 10‐week training protocol in trained adults. We hypothesized that leg curl exercise with the ankle in a plantarflexed position would enhance EMG activity, muscular strength, and hamstrings muscle thickness. We randomized the legs within a person to perform leg curl exercise with one in a plantarflexed position and the other in a dorsiflexed position. Experiment 1 revealed no significant differences between ankle positions in the EMG activity of hamstring muscle in either group (all p > 0.05). Experiment 2 revealed a significant pre‐ to post‐intervention increase in biceps femoris long head (BFLH) muscle thickness (p = 0.026) and isometric torque (p = 0.03), but there were no significant effects of the ankle position (p = 0.596) or interaction between ankle position and timepoint for these variables (p = 0.420). In sum, the ankle position did not have acute effects on hamstrings EMG activity, nor did it affect strength and hypertrophy adaptations after 10‐weeks of leg curl exercise training. Interestingly, however, the limb which performed leg curl exercise in a dorsiflexed position performed a higher total training volume.

Highlights

Different ankle positions (i.e. dorsiflexion or plantarflexion) do not affect hamstrings EMG activity during prone leg curl exercise.

Different ankle positions show similar adaptation in strength and hypertrophy of biceps femoris long head after 10 weeks of training.

Training in the plantarflexed position may be useful for time‐constrained individuals, allowing similar training adaptations with smaller training volume.
Effective plasmonic spectroscopic amplifiers for hyper-Raman scattering process
Authors: Alsawafta Mohammed
Published: May 2023

In an asymmetric Au cubic trimer, influence of the rotation angle (θ) and side length (w) on both plasmonic coupling features and corresponding enhancement factor of hyper-Raman scattering (HRS) process have been investigated comprehensively under the illumination of a longitudinally polarized light. The finite-difference time-domain (FDTD) electrodynamic simulation tool has been employed to calculate the optical cross-section and associated nearfield intensity of the irradiated coupled resonators. As θ increases, the polarization state that dominates the coupling phenomenon is gradually switched from facing sides into facing edges which results in (1) a dramatic change in the spectral response of the trimer and (2) a significant improvement in the nearfield intensity that is directly related to the improvement of HRS signal. Breaking size symmetry of the cubic trimer provides a novel approach to reach the desired spectral response that permits such trimer to be used as an active substrate for HRS procedures. After optimizing both the orientation angle and size of the interacting plasmonic characters forming of the trimer, the enhancement factor of HRS process can reach a value never reported before as high as 1 × 1021.
Interaction mediated electron transport within the many-body tunnelling Hamiltonian
Authors: Patton Kelly R
Published: May 2023

For a non-superconducting system and in the spirit of the transfer or tunnelling Hamiltonian formalism, an expression for the electronic tunnelling current through an insulating barrier is calculated, explicitly taking into account the effects of electron-electron interactions that can persist across the barrier. In the presence of a single tunnelling barrier, the exact Hamiltonian is projected onto the subspaces of the ‘left’ and ‘right’ conducting leads. In the weak-tunnelling limit, the well-known tunnelling Hamiltonian is recovered, along with an additional term. This additional term originates from the projection of the electron-electron interaction onto each subspace and corresponds to a correlated or interaction-mediated tunnelling. It is shown that the tunnelling current in this approximation is related to—in addition to the single-particle density of states—the two-particle spin-spin and density-density susceptibilities. The signatures of these terms have been observed in scanning tunnelling microscope experiments on atomic spin chains.
Ultra-high sensitivity optical fiber Vernier photothermal sensor based on WTe2
Authors: Ma Yukuan , Gu Qiongqiong , Zhou Hao , Huang Yulei , Yan Congliao , Wang Shutong , Wang Shaoqian , Deng Guoliang , Zhou Shouhuan
Published: May 2023

In this paper, a novel Vernier photo-thermal optical fiber sensor based on WTe2 is proposed. The sensor is composed of a single-sided gold-plated silicon wafer and a single-mode optical fiber, and is encapsulated with a capillary tube. The air cavity and the silicon wafer cavity are cascaded to have an optical Vernier effect, and the sensitivity can be selected by adjusting the length of the air cavity. The ultra-high sensitivity of 2.53 nm mW−1 has been obtained through experiments, which has certain potential in the fields of optical imaging, detection, and sensing.
Gain-switched 2.8 μm fluoride fiber laser pumped at 1550 nm
Authors: Xiao Yang , Xiao Xusheng , Guo Haitao
Published: May 2023

We demonstrated a gain-switched heavily erbium-doped fluoride fiber laser pumped at 1550 nm. A 2.8 μm short-pulsed laser with a maximum average output power of 350 mW and a practical optical-optical efficiency of ∼11.3% was obtained at a repetition rate of 50 kHz with a single pulse energy of 7 μJ, a pulse width of 938 ns, and a peak power of 7.5 W. Gain-switched temporal states with 1/n (n = 4,3,2) (ratio of signal pulses per pump pulses) pump repetition rates were first observed in the 2.8 μm erbium-doped fluoride fiber laser. These results indicate that the 1550 nm pulsed pumping scheme is an efficient and potential way for power scaling of 2.8 μm short-pulsed erbium-doped fluoride fiber lasers.
Optimization of the grain boundary diffusion process by doping gallium and zirconium in Nd–Fe–B sintered magnets
Authors: Li 李 Zhiteng 之藤 , Xu 徐 Haibo 海波 , Liu 刘 Feng 峰 , Lai 赖 Rongshun 荣舜 , Wu 武 Renjie 仁杰 , Li 李 Zhibin 志彬 , Zhang 张 Yangyang 洋洋 , Ma 马 Qiang 强
Published: May 2023

As the channel for grain boundary diffusion (GBD) in Nd–Fe–B magnets, grain boundary (GB) phases have a very important effect on GBD. As doping elements that are commonly used to regulate the GB phases in Nd–Fe–B sintered magnets, the influences of Ga and Zr on GBD were investigated in this work. The results show that the Zr-doped magnet has the highest coercivity increment (7.97 kOe) by GBD, which is almost twice that of the Ga-doped magnet (4.32 kOe) and the magnet without Ga and Zr (3.24 kOe). Microstructure analysis shows that ZrB2 formed in the Zr-doped magnet plays a key role in increasing the diffusion depth. A continuous diffusion channel in the magnet can form because of the presence of ZrB2. ZrB2 can also increase the defect concentration in GB phases, which can facilitate GBD. Although Ga can also improve the diffusion depth, its effect is not very obvious. The micromagnetic simulation based on the experimental results also proves that the distribution of Tb in the Zr-doped magnet after GBD is beneficial to coercivity. This study reveals that the doping elements Ga and Zr in Nd–Fe–B play an important role in GBD, and could provide a new perspective for researchers to improve the effects of GBD.
The Reissner–Nordström black hole surrounded by quintessence may not be destroyed
Authors: Tang 唐 Hao 浩 , Zhang 张 Jia 甲
Published: May 2023

In the study of weak cosmic censorship conjectures (WCCC), some research finds that the Reissner–Nordström black hole might be destroyed by a test particle with particular mass and charge under some conditions, which means that the naked singularity of the black hole could be observed. This is not allowed in WCCC. We have never observed such naked singularities which should not exist in theory, so we need to find a proper way to protect the black hole from being destroyed by such particles. In this paper, we study a Reissner–Nordström black hole that is surrounded by quintessence (RN-Q) and find that the black hole would be stable and safe because of the effective potential barrier induced by the quintessence term. This result may also show in a sense that the quintessence might have more potential value.
An injection-locking diode laser at 671 nm with a wide tuning range up to 6 GHz
Authors: Song 宋 Hong-Fang 红芳 , Shen 沈 Yue 玥 , Li 李 Ke 可
Published: May 2023

We present a compact injection-locking diode laser module to generate 671 nm laser light with a high output power up to 150 mW. The module adopts a master–slave injection-locking scheme, and the injection-locking state is monitored using the transmission spectrum from a Fabry–Pérot interferometer. Beat frequency spectrum measurement shows that the injection-locked slave laser has no other frequency components within the 150-MHz detection bandwidth. It is found that without additional electronic feedback, the slave laser can follow the master laser over a wide range of 6 GHz. All the elements of the module are commercially available, which favors fast construction of a complete 671-nm laser system for the preparation of cold 6Li atoms with only one research-grade diode laser as the seeding source.
Common Features of Free Particle Wave Functions in Curved Space-times
Authors: Moalem A , Gersten A
Published: May 2023

Quantum equations for massless particles of any spin and for massive spin one-half particles are considered in curved space-times. It is demonstrated that in stationary axially symmetric space-times the angular wave functions up to a normalization function are the same as in a Minkowski space-time. The radial wave functions satisfy second order nonhomogeneous differential equations with three nonhomogeneous terms which depend in a unique form on the ratio of time to space curvatures. For a Dirac spin one-half particle, in addition to these three terms a fourth term which depends on the particle rest mass is added.
Foundations for QED, Feynman operator calculus, Dyson conjectures, and Einstein’s dual theory
Authors: Gill Tepper L. , Parga Gonzalo Ares de
Published: May 2023

This paper reviews research on the foundations of quantum electrodynamics (QED). We show that there are three definitions of the proper time that follow from Einstein’s theory. The first definition is used to prove that the universe has a unique clock (Newton-Horwitz-Fanchi time) available to all observers. This clock is used to briefly discuss the mathematical foundations for Feynman’s time ordered operator calculus. We use this calculus to solve the first and second conjectures of Dyson for QED: that the renormalized perturbation series is asymptotic and, that the ultra-violet divergence is caused by a violation of the time-energy uncertainly relationship. The second definition gives Minkowski’s version of Einstein’s theory and its problems are briefly reviewed. The third definition gives the dual Newton, dual Maxwell and dual quantum theories. The theory is dual in that, for a set of n particles, every observer has two unique sets of global variables (X, t) and (X, τ) to study the system, where X is the canonical center of mass. Using (X, t) time is relative with speed c, while in (X, τ), time is unique with relative speed b. The dual Maxwell theory contains a longitudinal (dissipative) term in the E field wave equation, which appears instantaneously with acceleration and we predict that radiation from a cyclotron will not produce photoelectrons. It is shown that this term gives an effective mass for the photon. A major outcome is the dual unification of Newtonian mechanics and classical electrodynamics with Einstein’s theory and without the need for point particles or a self-energy divergency. This means that a second quantized version will not produce a self-energy or infrared divergency. These results along with the proof of Dyson’s second conjecture resolves all the problems with QED. The dual Dirac theory provides a new formula for the anomalous magnetic moment of a charged particle, which can give exact values for the electron, muon and proton g-factors.
On the electron spin and spectrum energy problems within the Fock many temporal and Feynman proper time paradigms
Authors: Prykarpatski Anatolij K.
Published: May 2023

The quantum electron spin structure and the photon dressed electron energy spectrum problem are reanalyzed in the framework of the Fock many-temporal parameter approach. There is analyzed the spin structure and its dependence on the symmetry properties of the related representations of the basic Clifford algebra, generated by creation-annihilation operators. The self-interaction phenomenon is discussed within the quantum renormalized Lorenz constraint on a suitably reduced Fock space. The electron energy spectrum is analyzed within the many-temporal Fock and Feynman proper time paradigms.
Signatures of 1.5 MeV leptons in nuclear reactions
Authors: Kovacs Andras , Zatelepin Valery , Baranov Dmitry
Published: May 2023

While experimental physics progressed tremendously since the 1970s, the neutron model has remained essentially unchanged. Motivated by developments in both experiments and theory, which we briefly review in section 1, we propose that the initial neutron decay step is not the emission of an 80 GeV mass boson particle, but the emission of a much lighter lepton particle. On the basis of well-known neutron data, in section 2 we estimate that this new lepton’s mass is 1.5 MeV.

Historically, investigations of deuteron photo-dissociation led nuclear scientists to assume that no electron-like particle is associated with neutron decay. We therefore re-examine these experiments in section 3. We demonstrate that deuteron photo-dissociation leads to 2p
+ + e
− products at high photon energies. Our calculations show why a deuteron always breaks up into p + n particles at <3 MeV photon energy.

Sections 4 - 7 discuss the properties and interactions of the 1.5 MeV lepton particle. Numerous investigations, including our own experiments, demonstrate the presence of negative elementary charges within atomic nuclei. The emission or absorption of negative nuclear charges involves the emission or absorption of a new lepton particle, which always decays into an electron. Various mass measurement methods converge to the same result: the emitted or absorbed lepton is approximately three times heavier than an ordinary electron. Specifically, we measure its mass to be 1553.5 keV.

Our work demonstrates that, despite being a single particle, the neutron comprises a positive and a negative elementary charge. To make sense of the neutron structure, it is necessary to firstly understand the proton’s and the newly discovered 1.5 MeV lepton’s internal structures. In section 9, we apply our results to better understand the neutron’s properties.
Towards testing a dark matter candidate that emerges from the scalar ether theory
Authors: Arminjon Mayeul
Published: May 2023

According to a scalar theory of gravity with a preferred frame, electromagnetism in the presence of a gravitational field implies that there is an additional energy tensor, which might contribute to dark matter. The expression of this tensor is determined by a mere scalar p, that depends on the EM field and (for a weak field) on the Newtonian gravitational field. We briefly recall why this tensor arises and how the EM field in a galaxy can be calculated. The data fields that enter the PDE for the scalar field p oscillate very quickly in space and time, as does the EM field. This prevents integration of that PDE at the relevant galactic scale. Therefore, a homogenization of that PDE has to be operated. We discuss in some detail three possible ways of applying the homogenization theory to that PDE: time, space, or spacetime homogenization. The second and third ways may lead to feasible, albeit heavy calculations.
Weyl and Majorana for Neutral Particles
Authors: Dvoeglazov Valeriy V.
Published: May 2023

We compare various formalisms for neutral particles. It is found that they contain unexplained contradictions. Next, we investigate the spin-1/2 and spin-1 cases in different bases. Next, we look for relations with the Majorana-like field operator. We show explicitly incompatibility of the Majorana anzatzen with the Dirac-like field operators in both the original Majorana theory and its generalizations. Several explicit examples are presented for higher spins too. It seems that the calculations in the helicity basis only give mathematically and physically reasonable results.
Group contraction in physics: History and potential
Authors: Knap Jaroslav
Published: May 2023

This article serves as a review of the mathematical tool of group contraction with an emphasis on physical applications. It was implicitly understood that some theories contain others as a special case (e.g., the relation between special relativity and Newtonian mechanics), but until the 1950s there was no firm mathematical grounding for such relations. We discuss the historical development of these concepts, their application to symmetry groups of space and time, and their relevance to the phenomenon of spontaneous symmetry breaking. Finally, we close by proposing a speculative chronology of space-time symmetries in the early universe.
The measurement in classical and quantum theory
Authors: Kryukov Alexey A.
Published: May 2023

The Bohigas-Giannoni-Schmit (BGS) conjecture states that the Hamiltonian of a microscopic analogue of a classical chaotic system can be modeled by a random matrix from a Gaussian ensemble. Here, this conjecture is considered in the context of a recently discovered geometric relationship between classical and quantum mechanics. Motivated by BGS, we conjecture that the Hamiltonian of a system whose classical counterpart performs a random walk can be modeled by a family of independent random matrices from the Gaussian unitary ensemble. By accepting this conjecture, we find a relationship between the process of observation in classical and quantum physics, derive irreversibility of observation and describe the boundary between the micro and macro worlds.
New technique of ion identification in Accelerator Mass Spectrometry using low-pressure TPC with GEM readout
Authors: Bondar A. , Buzulutskov A. , Parkhomchuk V. , Petrozhitsky A. , Shakirova T. , Sokolov A.
Published: May 2023

We have developed and successfully tested a low-pressure Time Projection Chamber (TPC) with Gas Electron Multiplier (GEM) readout for Accelerator Mass Spectrometry (AMS).

AMS facility in Novosibirsk has a problem of separating isobar ions of different chemical elements that have the same atomic mass. The typical example is radioactive isotopes 10Be and 10B that are used to date geological objects at a time scale of ten million years. To solve this problem, a new ion identification technique, namely that based on measuring both ion track ranges and ion energies in low-pressure TPCs with GEM readout, has been developed. This technique is proposed to be applied in AMS for dating geological objects, namely for geochronology of Cenozoic era.

In this work, we developed a new larger version of the TPC with a dedicated thin silicon nitride window for an efficient passage of ions. The TPC characteristics were studied in isobutane at low pressures using alpha particle sources. In addition, the use of GEM instead of THGEM has been shown to substantially improve the energy resolution at a nominal pressure (50 torr). Using these results and SRIM code simulations, it is shown that isobaric boron and beryllium ions can be effectively separated at AMS, providing efficient dating on a scale of ten million years. This technique will be applied in the AMS facility in Novosibirsk in the near future.
High efficiency, low cost, RF sources for accelerators and colliders
Authors: Ives R.L. , Read M. , Bui T. , Marsden D. , Collins G. , Freund H. , Ho R. , Higgins L. , Walker C. , Conant J. , Chase B. , Reid J. , Kroc T. , Yakovlev V. , Thangaraj J.C.T. , Dhuley R.C. , Potter J. , Jensen A. , Weatherford B. , Nanni E.A. , Tantawi S.
Published: May 2023

Accelerators for High Energy Physics (HEP) are large users
of energy, much of it in the form of radiofrequency (RF) power to
accelerate particles to very high energies. Proposed HEP projects
will require even larger amounts of RF energy. Increasing concerns
of the cost and availability of energy will require the HEP
community to use energy as efficeintly as possible. Successful
transfer of HEP technology to the public and private sectors will be
most effective if it is highly efficient.

Historically, the HEP community has utilized available RF power
sources, mainly in the form of vacuum tube technology, much of which
was developed during the cold war or is otherwized used in the
private sector. The private sector is moving to solid-state RF
sources which do not exibit the electrical efficiency that is needed
for future HEP projects.

Here, we summarize the state of the development of a number of RF
sources that promise efficeincies of 80% and above. We also outline
future efforts that are needed to fully realize the potential of
these sources.
Gauge theory for mixed p-spin glasses
Authors: Itoi C , Sakamoto Y
Published: May 2023

Physical quantities in the mixed p-spin glasses are evaluated with Nishimori’s gauge theory and several variance inequalities. The

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-symmetry breaking and the replica-symmetry breaking (RSB) are studied in finite and infinite dimensions. Obtained bounds on the expectation of the square of the magnetization and spontaneous magnetization enable us to clarify properties of paramagnetic and spin glass phases. It is proven that variances of ferromagnetic and spin glass order parameters vanish on the Nishimori line in the infinite volume limit. These results imply the self-averaging of these order parameters on the Nishimori line. The self-averaging of the spin glass order parameter rigorously justifies already argued absence of RSB on the Nishimori line.
Oxygen requirement analysis in the wastewater treatment plant using machine learning
Authors: Măcinic M E , Robescu L D , Boncescu C , Robescu D
Published: May 2023

The research presented in this article refers to the optimization of oxygen requirement in biological wastewater treatment using machine learning (ML) techniques with the highest efficiency of the process. The treatment technology of wastewater treatment plant consists of sequential biological reactor with nutrient removal. The analysis is based on the daily data over a period of 2 years, influent, respectively effluent wastewater characteristics, wastewater flow rate and concentration of oxygen in biological reactor. Octave software was used to build the model and it was obtained an accuracy of 85%.
Thermal bridge assessment at industrial buildings
Authors: Iancu I E , Moga L M
Published: May 2023

It is well known that the thermal performance of a building is influenced by the solutions that define the building’s envelope. In the case of industrial buildings, due to the use of different envelope solutions (e.g. sandwich panels, prefabricated concrete panels etc.), the types of thermal bridge details are often different in comparison to those currently found in residential, office and administrative buildings. Thus, several numerical simulations were performed by analysing details of envelope elements identified at industrial buildings, especially the areas prone to intensified heat flow (joint areas, intersections, glazed surfaces, and others.). Therefore, the paper will present the assessment of thermal bridge details for four industrial buildings having various destinations. The effects of two-dimensional heat transfer in envelope elements, such as windows, walls, foundations, roofs and doors, will be evaluated. The impact of the thermal bridges will be measured by verifying to what extent the level of thermal performance of each envelope component meets the thermal resistance requirements, as well as the building envelope ensures the global heat transfer coefficient for each of the studied cases. A series of conclusions and recommendations will be provided for specialists and designers in the building energetics field.
Antibacterial activity of green synthesized ZnO nano-flower using pineapple peel extract
Authors: Rini A S , Linda T M , Hamzah Y , Umar L , Sari M , Rati Y
Published: May 2023

Plant-based nanoparticles provide significant advantages over conventional physico-chemical techniques in medicine and biology. This paper reports the green route to synthesise ZnO particles using pineapple peel extract at various zinc precursor concentrations and evaluate their antibacterial activity. Morphological, structural, and optical properties of ZnO were characterised using SEM, XRD, FTIR, and UV–vis. The antibacterial potential of ZnO particles was evaluated against two clinical strains of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) using the paper disc diffusion method. SEM images exhibit flower-like ZnO with diameters in the range of 331–538 nm. The hexagonal wurtzite crystal phase of ZnO has been confirmed by XRD analysis with a crystal size of 14–17 nm. The FTIR spectrum has also validated the Zn-O bonding and the presence of additional functional groups in the samples. Antibacterial activity of the nanoflower ZnO towards E. coli and S. aureus displays inhibitory zone widths of 17.23 ± 3.03 mm and 30.14 ± 1.86 mm, respectively. These findings reveal that nanoflower ZnO produced using the pineapple peel extract exhibited a large bacterial inhibition zone, indicating that it is potentially used as food packaging or antibiotics.