bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lateral Mn5Ge3 spin-valve in contact with a high-mobility Ge two-dimensional hole gas
Authors: Weißhaupt David , Sürgers Christoph , Bloos Dominik , Funk Hannes Simon , Oehme Michael , Fischer Gerda , Schubert Markus Andreas , Wenger Christian , van Slageren Joris , Fischer Inga Anita , Schulze Jörg 
Published: October 2024

Abstract
Ge two-dimensional hole gases (2DHG) in strained modulation-doped quantum-wells represent a promising material platform for future spintronic applications due to their excellent spin transport properties and the theoretical possibility of efficient spin manipulation. Due to the continuous development of epitaxial growth recipes extreme high hole mobilities and low effective masses can be achieved, promising an efficient spin transport. Furthermore, the Ge 2DHG can be integrated in the well-established industrial complementary metal-oxide-semiconductor (CMOS) devices technology. However, efficient electrical spin injection into a Ge 2DHG—an essential prerequisite for the realization of spintronic devices—has not yet been demonstrated. In this work, we report the fabrication and low-temperature magnetoresistance (MR) measurements of a laterally structured Mn5Ge3/Ge 2DHG/ Mn5Ge3 device. The ferromagnetic Mn5Ge3 contacts are grown directly into the Ge quantum well by means of an interdiffusion process with a spacing of approximately 130 nm, forming a direct electrical contact between the ferromagnetic metal and the Ge 2DHG. Here, we report for the first time a clear MR signal for temperatures below 13 K possibly arising from successful spin injection into the high mobility Ge 2DHG. The results represent a step forward toward the realization of CMOS compatible spintronic devices based on a 2DHG.
London penetration depth in amorphous and crystalline Re–Lu films: Comment on ‘Superconductivity of amorphous and crystalline Re–Lu films’ (Teknowijoyo and Gulian 2024 Supercond. Sci. Technol. 37 035005)
Authors: Talantsev Evgeny F 
Published: October 2024

Abstract
Recently, Teknowijoyo and Gulian (2024 Supercond. Sci. Technol.
37 035005) deposited amorphous Re3.8Lu and polycrystalline Re10.5Lu films and reported several superconducting parameters for these films. One of the reported parameters, the ground-state London penetration depth,

λ

(
0
)

≅
5

nm

, was deduced from the lower critical field,

B

c
1

(
T
)

. The authors also reported the Ginzburg–Landau parameter

κ
=
0.89

for both films. Based on these values, the authors concluded that their films ‘being of type-II’ are ‘rather close to the theoretical boundary separating type-I and type-II superconductors of

κ
=
1

/

2

≈
0.71

.’ Here, I argue that the reported

λ

(
0
)

and

κ

(
0
)

are incorrect. It is more likely that the errors originate due to a confusion of CGS and SI units by the authors. The correct parameters deduced from the reported experimental data are larger by 2.5 orders of magnitude, i.e.

λ

(
0
)

≅
1300

nm

and

κ

(
0
)

≅
250

, which implies that amorphous and polycrystalline Re
x
Lu films are high-

κ

type-II superconductors.
Horizontally stacked inverted U-shaped dual-band implantable antenna with circularly polarized for biotelemetry application
Authors: Kumaravel Shanmugam , Karthikeyan Madurakavi 
Published: October 2024

Abstract
A horizontally stacked inverted U-shaped dual-band implantable antenna is proposed for RFID and health care monitoring implantable applications. The designed antenna operates at 0.952 GHz ultrahigh frequency band (UHF; 0.951–0.956 GHz) and 2.4 GHz industrial, scientific, and medical band (ISM; 2.4–2.4835 GHz) in a suitable feeding scheme. The shorting pin is used on the radiation patch to minimize the antenna structure. The final dimension of the designed antenna size is

9
×
9
×
0.635

mm

3

.

The defected ground structure (DGS) helped to produce radiation with circular polarization (CP) at 2.4 GHz resonant frequency. The designed antenna achieves an axial ratio (AR) bandwidth of 20% at 2.4 GHz resonant frequency. The antenna is designed on Rogers RT Duroid 6010 substrate and fabricated. The same dielectric material was used as a superstrate. At both the UHF and ISM frequency bands, the experiment was conducted using skin-mimicking gel and minced pork. The horizontally stacked inverted U-shaped antenna has a high peak gain of −27.5 dBi at 0.952 GHz. The computed maximum specific absorption ratio is within allowable bounds and complies with IEEE safety criteria.
Discovery of PdHx compounds using genetic algorithms and first-principles calculations
Authors: Hosseini S Vahid , Arab Hamed , Abbasnejad Mohaddeseh , Mohammadizadeh Mohammad Reza 
Published: October 2024

Abstract
In the present work, the variable-composition crystal structure prediction algorithm USPEX was combined with first-principles calculations to systematically explore stable PdH
x
compounds in the pressure range from 0 to 100 GPa. The predicted structures are PdH, Pd4H5, Pd2H, and PdH4, of which PdH has previously been synthesized. The electronic structures show that these compounds can be metallic, with Pd states dominating at the Fermi level. However, the hydrogen atoms do not play a main role in the electronic properties; their vibrations do contribute to the electron–phonon coupling. The predicted Pd4H5 has a superconducting transition temperature of ∼13 K, which is higher than that of PdH (∼8 K in the experiment). Additionally, PdH, Pd4H5, Pd2H, and PdH4 can be classified as phonon-mediated superconductors, falling into the low-coupling regime. Our results demonstrate that as the hydrogen concentration is increased in PdH
x
compounds, the superconducting transition temperature rises due to hydrogen vibrations, which is consistent with the experiment. Hence, the present study paves the way for discovering new PdH
x
compounds with promising superconducting transition temperatures.
Electromagnetism and Maxwellian Evolution Equations in terms of Darboux Frame in Minkowski Space with Abnormalities
Authors: Yanık Ebru , Ceyhan Hazal , Özdemir Zehra , Gök İsmail 
Published: October 2024

Abstract
Electromagnetic wave propagation is often thought of as the transport of polarised light and this behaviour is well defined by Maxwell’s equations when propagating in an optical fiber. In this paper, we examine the q − direction and n − direction Berry’s phase equation along a Darboux framed optical fibre in Minkowski space. Next, we define q − direction and n − direction for the electromagnetic curves of the Rytov parallel transport laws. And then, the application section, the connections between the Maxwellian evolution of the electromagnetic curve for Maxwell’s equation and the anholonomic coordinates are visualized and illustrated with the MAPLE program.
Generation of the flat-top beam using convolutional neural networks and Gerchberg-Saxton algorithm
Authors: Ma Long , Zhang Wei , Dai Xiangguang 
Published: October 2024

Abstract
Laser technology has made rapid progress in recent years and has been widely used in various fields such as medicine, biology, military, and materials science. However, the limitations of traditional Gaussian intensity distribution of the laser beams in applications have prompted the emergence and development of flat-top beam shaping technology, which has received widespread attention. Here, we introduce a new method for generating flat-top beams that combines the traditional Gerchberg-Saxton algorithm with convolutional neural networks, using spatial light modulators to achieve flat-top beam shaping. A comparative analysis was conducted by comparing the root mean square error and diffraction efficiency of the generated flat-top beam with the results obtained using only the traditional Gerchberg-Saxton algorithm. Compared with the traditional Gerchberg-Saxton algorithm, the method proposed in this paper can generate a flat-top beam with smaller differences from the target light intensity and higher energy utilization, providing new possibilities for the application of laser technology.
Impact of relativistic positron beam on ion-acoustic solitary, periodic and breather waves in Earths’ ionospheric region through the framework of KdV and modified KdV equation
Authors: Roy Ashim , Sarkar Tanay , Roy Subrata , Raut Santanu 
Published: October 2024

Abstract
This study explores the propagation characteristics of ion-acoustic periodic, soliton, and breather waves in electron-positron-ion (EPI) plasma with a relativistic positron beam. The Korteweg–de Vries (KdV) equation is obtained by applying the traditional reductive perturbation method (RPM) to the fundamental set of fluid equations. When the KdV model is unable to accurately represent the nonlinear system’s evolution, a modified Korteweg–de Vries (mKdV) equation is constructed. In both models, Jacobi elliptic functions are used to derive periodic solutions, and a connection between periodic waves and soliton solutions is established. Hirota’s bilinear method is used to generate breathers directly from the KdV type framework without utilizing the modified Schrödinger framework inferred from the KdV type framework, which is a prevalent method in studies of nonlinear waves. Numerical knowledge of various physical factors in the ionospheric region is incorporated into the model to elucidate wave propagation in the Earth’s upper atmosphere.
The mechanics of extruded polylactic acid: an investigation into the effects of its multiple recycling and the inclusion of fly ash
Authors: Balan G Sakthi , Raj S Aravind 
Published: October 2024

Abstract
This study examines variations in the material properties of the 3D printed polylactic acid (PLA) components after they have been recycled multiple times. Additionally, virgin polylactic acid was supplemented with fly ash from the thermal power plant, and the material’s behavior was examined after it was recycled on multiple times. By means of different tests, the impacts of filler addition on the mechanical behavior of the recycled materials are investigated. Using various forms including broken pieces, flakes, and fine powders, the filament extrusion was performed using used polylactic acid material during recycling. Under multiple recycling conditions, the mechanical characteristics of the polylactic acid and fly ash added polylactic (PLA-FA) were investigated. This work also investigates the impact of the polymer’s particulate size during the filament extrusion process. After recycling, it was found that the fine powder additions during the extrusion process provided high tensile strength of 32.61 MPa and flexural strength of 47.32 MPa for the PLA specimens. After recycling processes, the maximum tensile strength of 25.64 MPa and flexural strength of 50.22 MPa were found in fly ash enriched PLA. In contrast, the hardness of both PLA and fly ash-included PLA increased following each recycling procedure. Multiple recycling of PLA material turned the ductile material into brittle material by means of amorphous phase emergence. When compared to other particle sizes which were bigger in size, the specimens developed with filaments extruded with fine powder showed maximum results in all the tests. The tensile strength of PLA material decreased by 17.25%, while the tensile strength of PLA-FA material decreased by 21.35% after recycling. In PLA, the flexural strength drop following three recycling was 17.56% while in PLA-FA material it was 9.01%. After three times of material recycling, the hardness increased by 3.52% in PLA and by 2.48% in PLA-FA.
Performance of dual-band infrared photodetectors based on M-structure superlattices
Authors: Cheng Yifan , Wang Zhongxian , Chen Guanliang , Song Zhigang , Li Chuanbo 
Published: October 2024

Abstract
The mainstream dual-band photodetector structures are complex, requiring careful design of each absorption layer, making it difficult to customize according to specific requirements. We simplified the structure and proposed an alternative design, which based on the nBn barrier structure combined with the M-structure superlattice (M-SL). With the utmost consideration for lattice matching, we have enabled tailored design and arbitrary adjustment of the absorption coefficients for both detection bands and the overall absorption characteristics as needed. This manuscript presents a series of dual-band photodetectors. The performance of these devices was simulated at 77K, with quantum efficiency exceeding 22% in the MWIR band of the MWIR-LWIR detector, and normalized detectivity reaching 1011

cm
·

Hz

/

W

. Quantum efficiency in the LWIR to VLWIR bands surpasses 19%, with normalized detectivity reaching 1011

cm
·

Hz

/

W

.
A compact finite-difference and Haar wavelets collocation technique for parabolic volterra integro-differential equations
Authors: Mohammad Najem A , Sabawi Younis A , Sh. Hasso Mohammad 
Published: October 2024

Abstract
In this paper, a numerical investigation of a class of parabolic Volterra integro-differential equations (parabolic-VIDEs) is conducted. The approach focuses on semi-discretizing parabolic-VIDEs by utilizing a second-order compact finite difference method

O
(
δ

t

2

)

for the time variable and approximating the integral term using the trapezoidal rule. Further, the spatial derivative is approximated by Haar wavelet method. This hybrid methodology leverages the strengths of both techniques to solve the equations more efficiently and accurately. The error analysis, using L
2 and L
∞-norms, shows low computational costs. Numerical experiments show that second-order accuracy in both time and space, respectively. Stability and convergence of the proposed method are given through Sobolve space. Some numerical examples are tested for the effectiveness and accuracy of the proposed method. Furthermore, the presented numerical approach is compared with standard finite difference numerical methods and the results are reported in a table.
Stability analysis study for the time-fractional Galilei invariant advection-diffusion model of distributive order using an efficient hybrid approach
Authors: Cai Ruiqi , Kosari Saeed , Shafi Jana , Derakhshan Mohammad Hossein 
Published: October 2024

Abstract
In this manuscript, a new model of the time-fractional Galilei-invariant advection-diffusion model of distributed order is studied. An efficient hybrid numerical approach with high accuracy is used to estimate this equation. The finite difference numerical method is used to approximate the fractional operator in terms of the time variable and to approximate the integral term of distributed order, the Gaussian–Legendre integration is applied. To obtain a fully discrete numerical approach, we used a spectral element numerical approach, in which Legendre polynomials are used as the basis function. For the proposed numerical approach, the error and stability analysis are studied. For the efficiency of the numerical approach, some numerical examples are presented with graphs and tables.
Zirili map-based image encryption method for healthcare, military, and personal data security
Authors: Pal Puneet Kumar , Kumar Dhirendra 
Published: October 2024

Abstract
Chaotic maps have been widely explored for encrypting information pertaining to sensitive data sources such as medical fields, military operations, satellite imagery, and personal photographs. Developing chaotic maps with a wide range of chaotic dynamics is crucial for encryption applications to safeguard information. In this work, we have proposed a novel two-dimensional hyperchaotic Zirili map that exploits the properties of the Zirili test optimisation function. The proposed Zirili map demonstrates excellent chaotic behaviour compared to several chaotic maps in terms of bifurcation diagram, Lyapunov exponent, permutation entropy, correlation diagram, sample entropy and Kolmogorov entropy. The proposed Zirili map is utilised in confusion and diffusion processes to develop an efficient image encryption method. We have suggested cascading confusion transformation to reduce the correlation coefficient between adjacent pixels. Additionally, a novel modified cyclic diffusion with pixel mixing is proposed to enhance randomness in encrypted images. A thorough assessment of the proposed image encryption method is performed on a variety of image datasets by utilising multiple cryptanalysis methods, including key space analysis, information entropy, correlation coefficient evaluation, differential attack, key sensitivity testing, histogram analysis, computational time analysis, and occlusion and noise attacks. The quantitative evaluation measures obtained in terms of average information entropy with value 7.9989, number of pixel change rate with value 99.6112, and unified averaged changed intensity with value 33.4246 (averaged over several images) is better than other state-of-the-art image encryption methods, which indicate the robustness of the proposed image encryption method. Furthermore, analysis based on encryption time shows the superiority of the proposed image encryption algorithm over other related works. The experimental results confirm the methods reliability and robustness for its application in secure and practical encryption solutions for real-world applications.
The dependence of halo bias on the protohalo shape alignment with the initial tidal field
Authors: Lee Jounghun , Moon Jun-Sung 
Published: October 2024

Abstract
We present a numerical evidence supporting the primordial origin of secondary halo bias even on the galactic mass scale.
Analyzing the data from the TNG 300-1 simulations, we investigate the dependence of halo bias on the degree of misalignment between the protohalo inertia and
initial tidal tensors, τ, measured at redshift, z

i
=127. From the TNG 300-1 galactic halos in logarithmic mass range of 10.5 < m ≡ log[M/(h
-1
M
⊙)] ≤ 13
identified at z=0, 0.5 and 1, a clear signal of τ bias is detected. For the case that τ is measured from the initial tidal field smoothed on the scale of
Rf
/(h
-1Mpc) ≲ 1, the halo τ bias is found to be very similar in its tendency and amplitude to the spin bias at all of the three redshifts,
if the effects of backsplash halos are properly eliminated.
For the case of Rf
/(h
-1Mpc) = 2, the τ bias at z=1 turns out to behave like the age bias, diminishing rapidly in the range of m > 12.
At z=0 and 0.5, however, the τ and age bias factors show large differences in their overall strengths, which is attributed to the dominant nonlinear effects
that undermine the former but enhance the latter.
Given these numerical results along with the previous finding [1] that τ shares a large amount of mutual information with the formation epochs and
spin parameters of galactic halos, it is concluded that the origins of halo age and spin bias must be closely linked with the primordial factor, τ, and that
the difference in the tendency between the two bias factors on the galactic mass scale reflects the multi-scale influence of τ on the halo secondary properties.
Warm inflation with a heavy QCD axion
Authors: Berghaus Kim V. , Forslund Matthew , Guevarra Mark Vincent 
Published: October 2024

Abstract
We propose the first model of warm inflation in which the particle production emerges
directly from coupling the inflaton to Standard Model particles. Warm inflation, an early epoch
of sustained accelerated expansion at finite temperature, is a compelling alternative to cold
inflation, with distinct predictions for inflationary observables such as the amplitude of
fluctuations, the spectral tilt, the tensor-to-scalar ratio, and non-gaussianities. In our model
a heavy QCD axion acts as the warm inflaton whose coupling to Standard Model gluons sources the
thermal bath during warm inflation. Axion-like couplings to non-Abelian gauge bosons have been
considered before as a successful microphysical theory with emerging thermal friction that can
maintain finite temperature during inflation via sphaleron heating. However, the presence of light
fermions charged under the non-Abelian group suppresses particle production, hindering a
realization of warm inflation by coupling to QCD. We point out that the Standard Model quarks can
be heavy during warm inflation if the Higgs field resides in a high-energy second minimum which
restores efficient sphaleron heating. A subsequent large reheating temperature is required to
allow the Higgs field to relax to its electroweak minimum. Exploring a scenario in which hybrid
warm inflation provides the large reheating temperature, we show that future collider and beam
dump experiments have discovery potential for a heavy QCD axion taking the role of the
warm inflaton.
Cu-doped nanocomposite Pr2Fe14B/α-Fe ribbons with high (BH)max
Authors: Alam Mehran Khan , Raza Shahzab , Gao 高 Chengyong 成勇 , Han 韩 Guangbing 广兵 , Kang 康 Shishou 仕寿 
Published: October 2024

Abstract
The melt-spun ribbons of nominal composition Pr9Fe84.2–x
B6.2P0.3Zr0.3Cu
x
(x = 0, 0.5, 1, 2) were prepared at wheel speeds of 21 m·s−1, 27 m·s−1, 30 m·s−1, and 33 m·s−1. The XRD patterns show that as the wheel speed increases, the crystallinity of the 2:14:1 hard phase decreases, while that of the α-Fe soft phase increases. The (BH)max, remanence, and coercivity are improved from 63 kJ·m−3, 0.85 T, and 515 kA·m−1 for the Cu-free ribbons to 171 kJ·m−3, 1.08 T, and 684 kA·m−1 with x = 0.5. The high squareness ratio of J
r/J
s ∼ 0.82 at 0.5 at.% Cu (27 m·s−1) indicates strong exchange coupling due to small grain sizes of 15 nm and 30 nm for soft and hard magnetic phases, respectively. The SEM images revealed smooth morphology and uniform element distribution at 0.5 at.% Cu (27 m·s−1), contributing to the high magnetic properties. The low recoil permeability (μ
rec) value of 5.466 × 10−4 T/kA·m−1 to 1.970 × 10−4 T/kA·m−1 confirms the strong exchange coupling with x = 0.5 (27 m·s−1). The initial magnetization curves show that the coercivity mechanism of the Cu-free alloy evolves from the nucleation of the reverse domain to the domain wall pinning as the wheel speed increases, resulting in a high coercivity value of 818 kA·m−1 (33 m·s−1). Conversely, for the Cu-added alloy, the coercivity mechanism changes from pinning to the nucleation of the reverse domain from low to high wheel speed.
On the Formation of the Double Neutron Star Binary PSR J1846–0513
Authors: Jiang Long , Xu Kun , Zha Shuai , Guo Yun-Lang , Yuan Jian-Ping , Qian Xiang-Li , Chen Wen-Cong , Wang Na 
Published: October 2024

Abstract
The double neutron star PSR J1846–0513 is discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey. The pulsar is revealed to be harbored in an eccentric orbit with e = 0.208 and an orbital period of 0.613 day. The total mass of the system is constrained to be 2.6287(35)M
⊙, with a mass upper limit of 1.3455 M
⊙ for the pulsar and a mass lower limit of 1.2845 M
⊙ for the companion star. To reproduce its evolution history, we perform a 1D model for the formation of PSR J1846–0513 whose progenitor is assumed to be neutron star—helium (He) star system via MESA code. Since the large eccentricity is widely believed to originate from an asymmetric supernova explosion, we also investigate the dynamical effects of the supernova explosion. Our simulated results show that the progenitor of PSR J1846–0513 could be a binary system consisting of a He star of 3.3–4.0 M
⊙ and a neutron star in a circular orbit with an initial period of ∼0.5 day.
Revisit the γ-Ray Flare Associated with Blazar Mrk 421
Authors: Zeng Xiang-Tao , Tang Ze-Yuan , Fan Jun-Hui 
Published: October 2024

Abstract
A Very High-energy (VHE) flare was observed by Major Atmospheric Gamma Imaging Cherenkov Telescopes on MJD 57788. This VHE flare was characterized by increased VHE flux and short timescales. In this study, we used one-zone synchrotron self-Compton, two-zone, and spine/layer models to explore this VHE flare’s origin. The results indicate that this γ-ray flare can be explained by Inverse Compton Scattering radiation from the layer contributed gamma radiation and results in the γ-ray flare in a different way than the two-zone model. The difference between the two models lies in the performance of spectral energy distribution after γ-ray flare as well as a possible difference in the timescales of the flare.