bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating how subject teachers transition to integrated STEM education: A hybrid qualitative study on primary and middle school teachers
Authors: Mao Gang , Zhang Qianying , Ma Tingyan , Li Feiming , Lan Min 
Published: August 2024

AbstractEncouraging subject teachers to transition to integrated STEM education is an important measure to address the shortage of STEM teachers. However, there is limited research available on the process and characteristics of STEM teacher identity transformation. The study used a hybrid method of Grounded Theory and Epistemic Network Analysis to analyze interview texts of 10 STEM teachers from Zhejiang Province, China. Research has shown that subject teachers go through three stages when transitioning to integrated STEM education: imitation, exploration, and innovation. Throughout each stage, the teacher’s identity changes as they gain a better understanding of integrated STEM education, curriculum and project design, practical methods, and teaching reflection. The study has identified three paths for the transformation of STEM teacher identity, which are influenced by factors such as gender, professional background, school type, and location. Additionally, the study proposes strategies that could encourage subject teachers to transition toward STEM education.
Progress toward absolute calibrations of DC x-ray sources from 1 keV to &gt;30 keV for Z diagnostics applications
Authors: Webb Timothy J. , Lake Patrick W. 
Published: August 2024

Numerous x-ray diagnostics at the Z facility, time-resolved and time-integrated, would benefit from a local calibrated x-ray source. For many years, Z has used low-power Manson x-ray sources to provide some characterization information for components of Z diagnostics below 30 keV. More recently, we have acquired TruFocus x-ray sources, which operate at voltages up to 100 kV depending on the anode material and model. These DC sources have demonstrated good stability and repeatability. Absolute calibrations of either sources or detectors usually involve another calibrated detector from another source, which has not been readily available locally. Therefore, we have adopted the strategy of characterizing a sensitive semiconductor diode detector by controlling or inferring the active volume. This characterized detector is then used to scale the Manson x-ray spectral shape as measured by an Amptek energy-resolving detector. The result agrees well with the modeled source spectrum. We can apply this technique to the TruFocus as well.
Accurate and efficient open-source implementation of domain-based local pair natural orbital (DLPNO) coupled-cluster theory using a t1-transformed Hamiltonian
Authors: Jiang Andy , Glick Zachary L. , Poole David , Turney Justin M. , Sherrill C. David , Schaefer Henry F. 
Published: August 2024

We present an efficient, open-source formulation for coupled-cluster theory through perturbative triples with domain-based local pair natural orbitals [DLPNO-CCSD(T)]. Similar to the implementation of the DLPNO-CCSD(T) method found in the ORCA package, the most expensive integral generation and contraction steps associated with the CCSD(T) method are linear-scaling. In this work, we show that the t1-transformed Hamiltonian allows for a less complex algorithm when evaluating the local CCSD(T) energy without compromising efficiency or accuracy. Our algorithm yields sub-kJ mol−1 deviations for relative energies when compared with canonical CCSD(T), with typical errors being on the order of 0.1 kcal mol−1, using our TightPNO parameters. We extensively tested and optimized our algorithm and parameters for non-covalent interactions, which have been the most difficult interaction to model for orbital (PNO)-based methods historically. To highlight the capabilities of our code, we tested it on large water clusters, as well as insulin (787 atoms).
Amorphous/polycrystalline NiMn selenide for high-performance supercapacitors
Authors: Tang Lun-Qiang , Zhang Kai , Zeng Hong-Yan , Yan Wei , Yue Hong-Li , Wang Ming-Xin 
Published: August 2024

Transition-metal selenides have been extensively studied as promising electrode materials for supercapacitors. Engineering amorphous/crystalline heterostructures is an effective strategy to improve rich active sites for accelerating redox reaction kinetics but still lacks exploration. In this study, an amorphous/crystalline heterostructure was designed and constructed by selenizing the self-sacrificial template NiMnS to generate amorphous Mn/polycrystalline Ni0.85Se–NiSe2 heterophase via the phase transformation from metal sulfide into metal selenide. The synergy of the complementary multi-components and amorphous/polycrystalline heterophase could enrich electron/ion-transport channels and expose abundant active sites, which accelerated electron/ion transfer and Faradaic reaction kinetics during charging/discharging. As expected, the optimal NiMnSe exhibited a high specific charge (1389.1 C g−1 at 1 A g−1), a good rate capability, and an excellent lifespan (88.9% retention). Moreover, the fabricated NiMnSe//activated carbon device achieved a long cycle life and energy density of 48.0 W h kg−1 at 800 W kg−1, shedding light on the potential for use in practical applications, such as electrochemical energy-storage devices.
Deciphering TADF Mechanisms in Metal-Free Organic Emitters BrA-HBI: Utilizing Optimally Tuned Range-Separated Functionals for Insight
Authors: Yu 于 Chunyue 春悦 , Yin 尹 Hang 航 , Guo 郭 Jie 婕 , Zhang 张 Wentian 闻天 , Shi 石 Ying 英 
Published: August 2024

Abstract
Metal-free organic emitters, characterized by their thermally activated delayed fluorescence (TADF) properties, offer considerable promise for the creation of highly efficient organic light-emitting diodes (OLEDs). Recently, Shao et al. presented a novel excited state intramolecular proton transfer (ESIPT) system BrA-HBI, demonstrating an emission quantum yield of up to 50% [Adv. Funct. Mater.
32, 2201256 (2022)]. However, many open issues cannot be answered solely by experimental means only and require detailed theoretical investigations. For instance, what causes the activation of TADF from the Keto* tautomer and leads to fluorescence quenching in the Enol* form? Herein, we provide a theoretical investigation on the TADF mechanism of the BrA-HBI molecule by optimally tuned range-separated functionals. Our findings reveal that ESIPT occurs in the BrA-HBI molecule. Moreover, we have disclosed the reason for the fluorescence quenching of the Enol* form and determined that the T
2 state plays a dominant role in the TADF phenomenon. In addition, double hybrid density functionals method was utilized to verify the reliability of optimally tuned range separation functionals on the calculation of the TADF mechanism in BrA-HBI. These findings not only provide a theoretical reference for development of highly efficient organic light-emitting diodes, but also demonstrate the effectiveness of the optimally tuned range-separated functionals in predicting the luminescence properties of TADF molecules.
Hidden symmetries of power-law inflation
Authors: Chiba Takeshi , Houri Tsuyoshi 
Published: August 2024

Abstract
A scalar field with an exponential potential has been proposed as a model of inflation (called power-law inflation). Although it admits an exact solution, the integrability of the system has not been shown. We uncover the hidden symmetries behind the system by utilizing the Eisenhart lift of field theories. We find that a conformal Killing vector field in the field space exists only for a particular combination of exponential functions that includes a single exponential potential. This implies the existence of additional conserved quantity and explains the integrability of the system.
Self-interactions can (also) destabilize bosonic stars
Authors: Brito Marco , Herdeiro Carlos , Sanchis-Gual Nicolas , dos Santos Costa Filho Etevaldo , Zilhão Miguel 
Published: August 2024

Abstract
We study the dynamical stability of Proca-Higgs stars, in spherical symmetry. These are solutions of the Einstein-Proca-Higgs model, which features a Higgs-like field coupled to a Proca field, both of which minimally coupled to the gravitational field. The corresponding stars can be regarded as Proca stars with self-interactions, while avoiding the hyperbolicity issues of self-interacting Einstein-Proca models. We report that these configurations are stable near the Proca limit in the candidate stable branches, but exhibit instabilities in certain parts of the parameter space, even in the candidate stable branches, regaining their stability for very strong self-interactions. This shows that for these models, unlike various examples of scalar boson stars, self-interactions can deteriorate, rather than improve, the dynamical robustness of bosonic stars.
Gauge-invariant magnetic charges in linearised gravity
Authors: Hull Chris , Hutt Maxwell L , Lindström Ulf 
Published: August 2024

AbstractLinearised gravity has magnetic charges carried by (linearised) Kaluza–Klein monopoles. A gauge-invariant expression is found for these charges that is similar to Penrose’s gauge-invariant expression for the ADM charges. A systematic search is made for other gauge-invariant charges.
Comparing eccentric waveform models based on post-Newtonian and effective-one-body approaches
Authors: Kacskovics Balázs , Barta Dániel 
Published: August 2024

Abstract
In the present study, two numerical models were compared to each other, namely the CBWaves and SEOBNRE algorithms, developed using the post-Newtonian and effective-one-body approaches, respectively, for the study of binary black holes evolving on eccentric orbits. To map the mismatch between the two models 260 000 simulations were conducted – 20 000 for non-spinning configurations and 240 000 for spinning ones—on a common grid of parameter values over the parameter space. This space is defined by the mass ratio

q
≡

m
1

/

m
2

∈
[
0.1
,

1
]

, the gravitational mass

m
i

∈
[
10

M
⊙

,

100

M
⊙

]

of each component labeled by i, the corresponding spin magnitude

S
i

∈
[
0
,

0.6
]

and a constant initial orbital eccentricity e
0. A comprehensive investigation was conducted to determine whether there was a discrepancy in the waveforms generated by the two codes. This entailed an in-depth analysis of the mismatch, and an extensive comparison was carried out on the outlier points between the two codes.
Protocols for x-ray transient grating pump/optical probe experiments at x-ray free electron lasers
Authors: Fainozzi Danny , Cucini Riccardo , Vila-Comamala Joan , Lima Frederico , Ardana-Lamas Fernando , Bañares Luis , Bargheer Matias , Bencivenga Filippo , Berndt Nadia , Beye Martin , Biednov Mykola , Bonetti Stefano , Brioschi Marta , Cannizzo Andrea , Carrara Pietro , Chergui Majed , David Christian , Engel Robin Y , Ferrari Eugenio , Feurer Thomas , Frankenberger Paul , Gawelda Wojciech M , Gessini Alessandro , Heder Siti , Huang Xinchao , Khatu Nupur N , Knoll Martin , Madsen Anders , Mamyrbayev Talgat , Masciovecchio Claudio , Maznev Alexei A , Milne Christopher , Mincigrucci Riccardo , Nelson Keith A , Paltanin Ettore , Rossi Giorgio , Scholz Markus , Serrat Carles , Staub Urs , Szlachetko Jakub , Torre Renato , Dhanalakshmi-Veeraraj Mano R , Xu Han , Zalden Peter , Svetina Cristian 
Published: August 2024

Abstract
Transient grating spectroscopy is a specialized application of the four-wave-mixing methodology and constitutes a versatile technique for investigating the dynamics of vibrational, magnetic and electronic degrees of freedom of matter in a background-free fashion. Recent developments in free-electron laser sources have enabled the extension of this technique into the extreme ultraviolet range. Ongoing efforts to expand transient grating spectroscopy into the x-ray regime promise numerous advantages: (1) substantial penetration depths that allow for probing bulk material properties, (2) element specificity via specific core-excited states, and (3) short wavelengths that allow for excitation gratings with higher momentum transfer and improved spatial resolution. In this study, we comprehensively outline the procedures for conducting x-ray transient grating pump/optical probe experiment. The process encompasses the design and alignment of the experimental setup, as well as the subsequent steps involved in data acquisition and analysis. This paper is intended as a comprehensive guide for researchers interested in implementing x-ray transient grating spectroscopy, providing valuable insights into the intricacies of the experimental workflow required for this novel technique. Furthermore, we discuss the potential for extending this methodology to an x-ray pump/x-ray probe scheme, envisioning a future direction that holds promise for enhancing the capabilities and scope of x-ray transient grating spectroscopy, opening new opportunities for studying ultrafast processes with unprecedented temporal and spatial resolutions.
Non-itinerant-type ferromagnetism and the magnetocaloric response of quinary all-d-metal ribbon: Ni35Mn34.5Co14Fe1Ti15.5
Authors: Mandal Sourav , Nath Tapan Kumar 
Published: August 2024

Abstract
Most of the ferromagnetic shape memory (FSM) Heusler alloys, which are primarily studied in bulk form in the literature, exhibit p-d type hybridization. This study conducts a thorough multidirectional investigation of a strongly d-d hybridized quinary melt-spun annealed ribbon having the composition Ni35Mn34.5Co14Fe1Ti15.5 (NMCFT-1). This off-stoichiometric, polycrystalline FSM, fabricated using the melt-spin technique, exhibits a highly textured microstructure, double magnetic transitions and super-mechanical features mitigating brittleness. It crystallizes in a perfectly B2-type disorder austenite (Pm-3m, space group number 221) phase at room temperature. It has been hypothesized that geometric frustration is the causative factor for this disorder. Curie temperature of austenite phase (

T

C

A

) between paramagnetic → ferromagnetic state is found to be ∼364.57 K, whereas martensite transformation temperature from weak magnetic martensite state to ferromagnetic austenite state is ∼174.74 K. Calculated moments (effective moment,

μ

eff

= 5.12

μ

B

; low-temperature saturation moment,

μ

S

(or

M

S

(
0
)

) = 5.08

μ

B

) yield a Rhodes–Wohlfarth ratio of ∼1, indicating the existence of the non-itinerant nature of 3d electrons, whereas the ferromagnetism and the linear or non-linear dependency of

M

s

2

(
T

) on T
2 around

T

C

A

indicates the presence of long-range Rudermann–Kittel–Kasuya–Yosida-type interaction. More importantly, the maximum magnetic entropy change (

Δ

S

m

) obtained across the first-order magneto-structural transition and second-order magnetic transition are +18.2 J·kg−1K−1 at 6 T and −8.8 J·kg−1K−1 at 2 T, respectively, while a very high working temperature span (ΔT
FWHM) of 28.561 K and 6.922 K are found for the same condition. The sample exhibits a significant relative cooling power of 402.98 J·kg−1 at a magnetic field of 6 T across the FOMT and 60.19 J·kg−1 at a 2 T field across the SOMT, respectively, along with excellent mechanical features such as a Vickers hardness (HV) of 411.80 HV (∼4.04 GPa). Meanwhile, Chen’s super hard model fails to predict the ribbon’s HV value, but Miao’s hard model does, indicating that the ribbon is hard but not super hard. It also paves the way for additional investigation into innovative FSMs like this.
Oxygen vacancies kinetics in TaO

2
−
h

/Ta2O

5
−
x

memristive interfaces
Authors: Ferreyra C , Leal Martir R , Rubi D , Sánchez M J 
Published: August 2024

Abstract
Oxygen vacancies (OV) are pervasive in metal oxides and play a pivotal role in the switching behaviour of oxide-based memristive devices. In this study we address OV dynamics in Pt/TaO

2
−
h

/Ta2O

5
−
x

/TaO

2
−
y

/Pt devices, through a combination of experiments and theoretical simulations, In particular, we focus on the RESET transition (from low to high resistance) induced by the application of electrical pulse(s), by choosing different initial OV profiles and studying their kinetics during the mentioned process. We demonstrate that by selecting specific OV profiles it is possible to tune the characteristic time-scale of the RESET. Finally, we show that the implementation of gradual RESETs, induced by applying many (small) successive pulses, allows estimating the activation energies involved in the OV electromigration process. Our results help paving the way for OV engineering aiming at optimizing key memristive figures such as switching speed or power consumption, which are highly relevant for neuromorphic or in-memory computing implementations.
Heusler alloy Mn2CoAl: structural, magnetic and electronic properties
Authors: Yang J Y , Xiang X J , Tan Z J , Zhang X K , Pan S , Chen J , Xu G Z 
Published: August 2024

Abstract
In this study, we report on the detailed atomic ordering, magnetic and electrical properties of the Heusler alloy Mn2CoAl, studied via combined experimental methods and a theoretical calculation approach. Our studies confirm the Hg2CuTi-type crystal structure of Mn2CoAl with 25% anti-site disorder between Mn (B:1/4,1/4,1/4) and Co(C:1/2,1/2,1/2) sites. Neutron powder diffraction measurements identify the antiparallel spin couplings between Mn:A↓ and Mn:B↑, Co:C↑, resulting in a ferrimagnetic structure with a net magnetic moment of ∼1.6 μ
B at room temperature. In terms of the electronic calculations, we find that the anti-site atoms will contribute large densities of states at the Fermi level, thus destroying the spin gapless band structure and making Mn2CoAl a normal ferrimagnetic metal. This report is intended to establish a basic understanding of the structure and physical properties of Mn2CoAl.
Low-current gliding DC discharge in high-speed flows
Authors: Kornev K N , Logunov A A , Dvinin S A 
Published: August 2024

Abstract
A low-current gliding discharge (current range 1–5 A) in high-speed air flows of 100–250 m s−1 was experimentally studied. A high-voltage direct current source with a maximum voltage of 4.5 kV was used to create the discharge. The average electron concentration n
e ∼ 1014 cm−3 and the plasma ionization degree were determined by measuring the Stark broadening of the hydrogen H
β
line (λ
Hβ
= 486.1 nm). The estimates of the electric field (E ∼ 100 V cm −1 ÷ 600 V cm−1) in the discharge positive column were found using time-synchronized high-speed video recordings and oscillograms. The gas rotational temperature T
g = 7000–9500 K and the vibrational temperature T
v = 7000–11 000 K were estimated using optical emission spectroscopy. Time-resolved spectroscopy is used to investigate the effective plasma channel spatial regions from which the N, NH, N2
+, O and OH molecules radiate. The difference of the obtained radii indicates the presence of a radial temperature gradient and inhomogeneous plasma composition in the discharge cross section. The possibility of using of gliding discharge to ignite hydrocarbon-air mixtures in the ramjet engines combustors has been experimentally demonstrated.
A 85Rb transverse modulation magnetometer in the geophysical range based on atomic alignment states
Authors: Shi Tao , Jin Ge , Zhang Hong , Zou Sheng 
Published: August 2024

Abstract
We have constructed a transverse modulated magnetometer based on spin alignment in a paraffin-coated 85 Rb cell operated in a geophysical magnetic field of 47.1 µT. When an orthogonal driving magnetic field (

x
^

axis) is resonant on the Larmor frequency (

z
^

axis), we have proposed a new method to zero the static residual magnetic fields in the transverse plane and achieved a sensitivity of

1.8

pT

Hz

−
1

with bandwidth of 200 Hz. The repump light (

F

g

=
2
→

F

e

=
2

) redistributes the populations in the ground state, rendering the state

|

F

g

=
2
⟩

dark. This effect significantly amplifies the optical rotation signals nearly fourfold. The numerical solution of the Liouville equation is in good agreement with the experimental results. By using perturbation treatment and employing appropriate approximations, the derived analytical expressions for optical rotation are deduced to succinctly elucidate the dynamics of atomic alignment under parametric modulation. These outcomes could be extended for the advancement of an alignment magnetometer that has been designed to detect a weak magnetic signal in the geophysical range.
Magnetism of pseudospin-1/2 pyrochlore antiferromagnet Na3Co(CO3)2Cl
Authors: Nawa Kazuhiro , Murasaki Ryo , Itoh Shinichi , Saito Hiraku , Nojiri Hiroyuki , Dela Cruz Clarina , Okuyama Daisuke , Yoshida Masahiro , Ueta Daichi , Yoshizawa Hideki , Sato Taku J 
Published: August 2024

Abstract
Pyrochlore magnets have attracted interest as systems for realizing critical phenomena, rich magnetic structures, associated topological band structures, and nontrivial quantum phases. Na3Co(CO3)2Cl is a pseudospin-1/2 antiferromagnet in which the Co2+ ions form a pyrochlore network. Its structural and magnetic properties were investigated using magnetization, heat capacity, ESR, single-crystal x-ray diffraction, powder neutron diffraction and powder inelastic neutron scattering. Magnetization and heat capacity measurements indicated a ground-state doublet, which is regarded as pseudospin 1/2, dominated the magnetic properties at low temperatures, with a magnetic exchange of 9.6 K. As the temperature decreases, a magnetic transition is observed at 1.6 K, which is confirmed to be an all-in-all-out magnetic order. The crystal field excitations observed by inelastic neutron scattering experiments indicated the Ising nature of the ground-state doublet. This thorough study revealed that Na3Co(CO3)2Cl can be regarded as a pseudospin-1/2 pyrochlore lattice antiferromagnet with dominant Ising-type interactions.
Object registration techniques for 3D particle tracking
Authors: Hendriksen L A , Sciacchitano A , Scarano F 
Published: August 2024

Abstract
Image based three-dimensional (3D) particle tracking is currently the most widely used technique for volumetric velocity measurements. Inspecting the flow-field around an object is however, hampered by the latter, obstructing the view across it. In this study, the problem of measurement limitations due to the above is addressed. The present work builds upon the recent proposal from Wieneke and Rockstroh (2024 Meas. Sci. Technol.
35 055303), whereby the information of the occluded lines of sight can be incorporated into the particle tracking algorithm. The approach, however, necessitates methods that accurately evaluate the shape and position of the object within the measurement domain. Methods of object marking and the following 3D registration of a digital object model (CAD) are discussed. For the latter, the iterative closest point registration algorithm is adopted. The accuracy of object registration is evaluated by means of experiments, where marking approaches that include physical and optically projected markers are discussed and compared. Three objects with growing level of geometrical complexity are considered: a cube, a truncated wing and a scaled model of a sport cyclist. The registered CAD representations of the physical objects are included in aerodynamic experiments, and the flow field is measured by means of large-scale particle tracking using helium filled soap bubbles. Results indicate that object registration enables a correct reconstruction of flow tracers within regions otherwise affected by domain clipping as a consequence of obstructed camera lines-of-sight. Finally, the combined visualization of the object and the surrounding flow pattern offers means of insightful data inspection and interpretation, along with posing a basis for particle image velocimetry data assimilation at the fluid-solid interface.