bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatially confined synthesis of large-sized MoS2 nanosheets in molten KSCN toward efficient hydrogen evolution
Authors: Nan Kaikai , Chen Qing , Wang Zuhao , Cheng Long , Liu Dezheng , Du Hongfang , Lin Liangxu
Published: July 2024

Low-temperature KSCN molten salt is a promising technique to synthesize defect-rich MoS2 catalysts for hydrogen evolution reaction (HER). However, owing to the fast ion diffusion rate for rapid crystal growth, the resultant catalysts show a morphology of microsphere, which aggregates from MoS2 nanosheets, to suppress the catalytic performance. In this work, large-sized few-layer MoS2 nanosheets are synthesized via a spatial confinement strategy by adding inert NaCl into the KSCN molten salt. With the NaCl spacer to physically block the long-distance ion diffusion and isolate the chemical reaction, the MoS2 nucleation and subsequent crystal growth could be controlled, guiding the nanosheets to grow along the narrow gap between the NaCl crystals to avoid aggregation. As a result, ultrathin MoS2 nanosheets with a large geometry size are constructed. Profiting from the architecture to expose active sites and boost charge transfer kinetics, the large-sized few-layer MoS2 nanosheets exhibit an impressive HER performance, showing a small η
10 of 160 mV and a low Tafel slope of 53 mV dec−1 with excellent stability. This work provides not only an efficient HER catalyst but also a facile spatial confinement technique to design and synthesize a large spectrum of transition metal sulfides for broad uses.
Sunlight-mediated removal of endocrine disruptors from wastewater using trimetallic core-shell Ag-TeO2@ZnO nanocomposites
Authors: Joshi Preeti , Patel Rajendra , Singh Aishwarya , Nenavathu Bhavani Prasad Naik , Sharma Manu , Verma Swati , Sillanpää Mika
Published: July 2024

The current work emphasizes the preparation of trimetallic core-shell Ag–TeO2@ZnO nanocomposites (NCs) by thermo-mechanical method for the efficient photocatalytic degradation of 2,4-Dichlorophenol and β-naphthol pollutants. FE-SEM shows that Ag and TeO2 nanoparticles are deposited on the surface of ZnO nanotubes. The band gap of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are found to be 3.16 and 2.96 eV, respectively. The calculated specific surface area (SBET) of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are 40.47 and 45.66 m2 g−1 respectively, confirming that Ag and TeO2 nanoparticles contribute to increasing in surface area of pure ZnO. The synthesised nanocomposite showed excellent photocatalytic performance for the degradation of β -naphthol (95.6%) in 40 min at the concentration of (0.6 mg ml−1) and 2,4-DCP (99.6%) in 180 min (0.4 mg ml−1) under natural sunlight. Cyclic Voltammetry and Electrochemical Impedance Spectroscopy were carried out to study the electrochemical properties. The determination of reactive oxygen species (ROS) confirmed that the degradation of the pollutants by 5 wt% Ag–TeO2@ZnO NCs was due to the formation of superoxide radicals. Electron paramagnetic resonance revealed the presence of sharp signals in pure ZnO nanoparticles at g ∼1.95 and oxygen vacancy peak at g ∼2.01 in 5 wt% Ag–TeO2@ZnO NCs. To study the mechanism behind the degradation of pollutants, Scavenger test using histidine and ascorbic acid (ROS scavengers) was performed. The synthesised nanocomposites are highly stable and showed enhanced efficiency up to three cycles, confirming their reusability as a photocatalyst.
The dynamics of Lato Lato ball collisions
Authors: Wibowo Edy , Ulya Naily , Marwoto Putut , Suwandi  , Suproyogi
Published: July 2024

Lato Lato is a toy that consists of two identical solid balls that are secured together with a rope and can be used as a learning tool in physics. In this study, we examined why the Lato Lato toy uses two balls with the same mass rather than balls with different masses. The collision of the two Lato Lato balls can be considered an elastic collision. The two balls move symmetrically at the same velocity and form a semi-circular route with opposing motion directions when we use Lato Lato with the same ball mass (

m
2

=

m
1

). The angular momentum of the two balls is also the same but in opposite directions, so they cancel each other out. Hence, the two balls travel steadily when Lato Lato is performed. This condition leads to a balanced movement of the Lato Lato system and prevents it from collapsing. On the other hand, because of their disparate masses (

m
2

>

m
1

), the two balls of Lato Lato move in an imbalanced manner. A lighter ball travels farther because it moves more quickly than a heavier ball. The angular momentum of the two balls is in opposite directions but not of the same magnitude, so they do not cancel each other out. This results in unstable movement of the two balls when Lato Lato is played. Therefore, the two balls no longer collide centrally, like in Lato Lato, with the same mass, but the collision is glancing. Then, the motion of the two balls facilitates collapse easily. This work can enrich students’ understanding of collisions beyond the collisions of two objects commonly discussed in textbooks.
One-step inverse generation network for sparse-view dual-energy CT reconstruction and material imaging
Authors: Zhang Xinrui , Li Lei , Wang Shaoyu , Liang Ningning , Cai Ailong , Yan Bin
Published: July 2024

Objective. Sparse-view dual-energy spectral computed tomography (DECT) imaging is a challenging inverse problem. Due to the incompleteness of the collected data, the presence of streak artifacts can result in the degradation of reconstructed spectral images. The subsequent material decomposition task in DECT can further lead to the amplification of artifacts and noise. Approach. To address this problem, we propose a novel one-step inverse generation network (OIGN) for sparse-view dual-energy CT imaging, which can achieve simultaneous imaging of spectral images and materials. The entire OIGN consists of five sub-networks that form four modules, including the pre-reconstruction module, the pre-decomposition module, and the following residual filtering module and residual decomposition module. The residual feedback mechanism is introduced to synchronize the optimization of spectral CT images and materials. Main results. Numerical simulation experiments show that the OIGN has better performance on both reconstruction and material decomposition than other state-of-the-art spectral CT imaging algorithms. OIGN also demonstrates high imaging efficiency by completing two high-quality imaging tasks in just 50 seconds. Additionally, anti-noise testing is conducted to evaluate the robustness of OIGN. Significance. These findings have great potential in high-quality multi-task spectral CT imaging in clinical diagnosis.
System size scaling of triangularity effects on global temperature gradient-driven gyrokinetic simulations
Authors: Di Giannatale Giovanni , Bottino Alberto , Brunner Stephan , Murugappan Moahan , Villard Laurent
Published: July 2024

In this work, we explore the triangularity effects on turbulent transport employing global gyrokinetic simulations performed with the ORB5 code. Numerous experiments on the Tokamak á Configuration Variable (TCV) and, more recently, on the DIII-D machine, have demonstrated superior confinement properties in L-mode of negative triangularity (NT) over positive triangularity (PT) configuration. This presents a particularly attractive scenario, as L-mode operation eliminates or significantly mitigates the presence of hazardous edge-localized modes (ELMs). However, a full theoretical understanding of all these observations remains elusive. Specifically, questions remain about how NT improvements can extend to the core where triangularity is very small, and whether these improvements can scale to larger devices. This paper addresses these two questions. Our analysis is divided into two parts: we first demonstrate that the confinement enhancement in NT configurations arises from the interdependent edge-core dynamics, and then we present the results of a system size scan. Crucially, we find that the relative turbulent transport reduction of NT over PT appears not to be contingent on machine dimensions or fluctuation scales and is moreover robust with respect to variations in plasma profiles. This insight underscores the fundamental nature of the NT confinement advantage and paves the way for its potential application in future fusion devices, regardless of their size.
Insight in NO synthesis in a gliding arc plasma via gas temperature and density mapping by laser-induced fluorescence
Authors: Manaigo Filippo , Chatterjee Abhyuday , Bogaerts Annemie , Snyders Rony
Published: July 2024

A gliding arc (GA) plasma, operating at atmospheric pressure in a gas mixture of 50% N2 and 50% O2, is studied using laser-induced fluorescence spectroscopy. The main goal is to determine the two-dimensional distribution of both the gas temperature and the NO ground state density in the afterglow. As GA plasma discharges at atmospheric pressure normally produce rather high NO
x
densities, the high concentration of relevant absorbers, such as NO, may impose essential restrictions for the use of ‘classical’ laser-induced fluorescence methods (dealing with excitation in the bandhead vicinity), as the laser beam would be strongly absorbed along its propagation in the afterglow. Since this was indeed the case for the studied discharge, an approach dealing with laser-based excitation of separate rotational lines is proposed. In this case, due to a non-saturated absorption regime, simultaneous and reliable measurements of both the NO density and the gas temperature (using a reference fitting spectrum) are possible. The proposed method is applied to provide a two-dimensional map for both the NO density and the gas temperature at different plasma conditions. The results show that the input gas flow rate strongly alters the plasma shape, which appears as an elongated column at low input gas flow rate and spreads laterally as the flow rate increases. Finally, based on temperature map analysis, a clear correlation between the gas temperature and NO concentration is found. The proposed method may be interesting for the plasma-chemical analysis of discharges with high molecular production yields, where knowledge of both molecular concentration and gas temperature is required.
Numerical investigation of discharge evolution and breakdown characteristics of ArF excimer lasers
Authors: Ma Xiaochi , Bai Luying , Zhu Yifei , Jiang Xinxian , Wu Yun
Published: July 2024

The corona bar induced pre–ionization is a crucial preliminary process in the operation of ArF excimer lasers, directly impacting the uniformity and stability of output laser. The ultraviolet corona pre–ionization, as the mainstream method, is tightly coupled with the main discharge process, which complicates analysis. Here, we establish a numerical model of a single pulse discharge incorporating an external circuit to analyze the pre–ionization process and its influence on the breakdown characteristics. (1) By adopting detailed input parameters of photoionization model, we observe uniform and dispersed plasma propagation from the corona bar to the main gap. (2) An artificial boundary condition is proposed to investigate the phenomenological effect of high–energy electrons emission, emphasizing the influence of surface discharge along the cathode. (3) The propagation and breakdown characteristics of the two pre–ionization setup methods, photoionization and background electron density, are compared numerically. This study enhances the understanding of the pre–ionization process in ArF excimer lasers and provides theoretical insights for their optimization and design.
Kinetic simulations of capacitively coupled plasmas driven by tailored voltage waveforms with multi-frequency matching
Authors: Yu Shimin , Wu Hao , Yang Shali , Wang Lu , Chen Zhipeng , Wang Zhijiang , Jiang Wei , Schulze Julian , Zhang Ya
Published: July 2024

Impedance matching is crucial for optimizing plasma generation and reducing power reflection in capacitively coupled plasmas (CCP). Designing these matchings is challenging due to the varying and typically unknown impedance of the plasma, especially in the presence of multiple driving frequencies. Here, a computational design method for impedance matching networks (IMNs) for CCPs is proposed and applied to discharges driven by tailored voltage waveforms (TVW). This method is based on a self-consistent combination of particle in cell/Monte Carlo collision simulations of the plasma with Kirchhoff’s equations to describe the external electrical circuit. Two Foster second-form networks with the same structure are used to constitute an L-type matching network, and the matching capability is optimized by iteratively updating the values of variable capacitors inside the IMN. The results show that the plasma density and the power absorbed by the plasma continuously increase in the frame of this iterative process of adjusting the matching parameters until an excellent impedance matching capability is finally achieved. Impedance matching is found to affect the DC self-bias voltage, whose absolute value is maximized when the best matching is achieved. Additionally, a change in the quality of the impedance matching is found to cause an electron heating mode transition. Poor impedance matching results in a heating mode where electron power absorption in the plasma bulk by drift electric fields plays an important role, while good matching results in the classical α-mode operation, where electron power absorption by ambipolar electric fields at the sheath edges dominates. The method proposed in this work is expected to be of great significance in promoting TVW plasma sources from theory to industrial application, since it allows designing the required complex multi-frequency IMNs.
Nonlinear behaviors in back-gate effects of FDSOI MOSFETs at cryogenic temperatures
Authors: Hu Yibo , Ren Zhipeng , Yin Yizhe , Chen Jing
Published: July 2024

In this work, we systematically investigate the DC performance of fully depleted silicon-on-insulator (FD-SOI) MOSFETs at both room and cryogenic temperatures as low as 77 K. The influences of back-gate bias on normal and flip-well devices are measured and analyzed. Both types devices display non-linear behaviors when adjusting the back-gate voltage at cryogenic temperatures. Notably, the non-linear effects are more prominent in normal-well devices. The possible reasons are analyzed and verified by technology computer aided design simulation, suggesting that normal-well devices are more susceptible to the formation of depletion regions between the buried oxide layer and the well. This phenomenon disrupts the linearity of the back-gate effect. This research contributes to understanding and characterizing of the back-gate effects in cryogenic environments and holds potential for high-performance computing applications.
Piezoelectric adaptive active vibration suppression for wind-tunnel model support sting
Authors: Li Weiguang , Yang Zhichun , Zhu Ximing , Liu Ke
Published: July 2024

Due to flow separation and turbulence, the slender cantilever aircraft model support system is prone to low-frequency and large-amplitude resonance in the wind tunnel tests, resulting in a decrease in test data quality, a limited test envelope, and even threatening the safe operation of the wind tunnel. A piezoelectric active damping system based on the filtered-x least mean square algorithm is proposed to effectively suppress the vibration of the wind-tunnel model support sting. Firstly, a modified variable step least mean square algorithm is proposed to address the issue that the fixed-step algorithms limit each other in terms of convergence speed and steady-state error. Following that, a variable step filtered-x least mean square algorithm based on reference signal reconstruction is developed, and the corresponding feedback controller is designed to perform the ground tests of the piezoelectric active damping system for the wind-tunnel model support sting. The experimental results show that the proposed algorithm has a faster convergence speed and lower steady-state error than the traditional algorithms, as well as strong anti-noise and adaptive control abilities that significantly improve the active vibration suppression effect of the wind-tunnel model support sting.
Distinguishing the topological charge of vortex beam via Fourier back plane imaging with chiral windmill structure
Authors: Guo Yangzhe , Li Jing , Fang Yurui
Published: July 2024

In recent years, research on the interaction between orbital angular momentum (OAM) of light and matter has shown a continuous influx of investigations. OAM possesses distinct properties, such as a degree of freedom with multiple states, vortex characteristics, and topological properties, which expand its applications in optical communication, optical sensing, and optical manipulation. We have observed different phenomena in the chiral metal windmill structure under excitation of spin angular momentum (SAM)-OAM beam generated by Q-plate than under SAM excitation. Fourier back focal plane (FBP) imaging under SAM beam excitation easily identifies the chirality and geometric properties of the structure. When the SAM-OAM beam excites the structure, FBP not only identifies its chirality and geometric properties but also distinguishes different OAM topological charges and signs, as well as the degree of elliptic polarization. The Stokes parametric FBP imaging reveals asymmetric polarization distribution resulting from the interaction between a vortex beam and the chiral structure. Moreover, it clearly reflects the conversion process of SAM to OAM. The experimental results match well with simulation results. These findings hold valuable insights for the advancement of optical information storage and communication using OAM, opening up new possibilities for further exploration in this field.
Dissipative quantum Hopfield network: a numerical analysis
Authors: Torres Joaquín J , Manzano Daniel
Published: July 2024

We present extensive simulations of a quantum version of the Hopfield neural network to explore its emergent behavior. The system is a network of N qubits oscillating at a given Ω frequency and which are coupled via Lindblad jump operators built with local fields hi
depending on some given stored patterns. Our simulations show the emergence of pattern-antipattern oscillations of the overlaps with the stored patterns similar (for large Ω and small temperature) to those reported within a recent mean-field description of such a system, and which are originated deterministically by the quantum term including

s
x
i

qubit operators. However, in simulations we observe that such oscillations are stochastic due to the interplay between noise and the inherent metastability of the pattern attractors induced by quantum oscillations, and then are damped in finite systems when one averages over many quantum trajectories. In addition, we report the system behavior for large number of stored patterns at the lowest temperature we can reach in simulations (namely

T
=
0.005

T

C

). Our study reveals that for small-size systems the quantum term of the Hamiltonian has a negative effect on storage capacity, decreasing the overlap with the starting memory pattern for increased values of Ω and number of stored patterns. However, it also impedes the system to be trapped for long time in mixtures and spin-glass states. Interestingly, the system also presents a range of Ω values for which, although the initial pattern is destabilized due to quantum oscillations, other patterns can be retrieved and remain stable even for many stored patterns, implying a quantum-dependent nonlinear relationship between the recall process and the number of stored patterns.
Flow analysis of a two-layered micropolar fluid in a catheterized oesophageal tube under the influence of a dilating amplitude: Application to pre-diagnosis of oesophageal motility disorder
Authors: Pandey Sanjay Kumar , Pandey Anupam Kumar
Published: July 2024

This study employs the Homotopy perturbation method to analyze the behavior of immiscible, incompressible fluids within a cylindrical coaxial tube, focusing on scenarios relevant to physiological fluid dynamics, particularly in the catheterized oesophagus and similar biological systems. Adopting long-wavelength and low Reynolds number approximations, a two-layered model is proposed with a micropolar fluid in the core and a Newtonian fluid in periphery regions. Parameters such as velocity, flux, friction, pressure, and impedance variations are formulated, particularly under the influence of dilating wave amplitude. Generally, when a catheter is introduced, pressure rises. It is further found that while pressure falls with increasing micropolar parameter, it rises with coupling number upon catheter insertion. Thus feeding patients with micropolar fluids during catheter-assisted pre-diagnosis is impractical due to associated pressure rise. Observations suggest a complex pressure profile during bolus passage through the oesophagus due to the broadening of the catheter size. Additionally, impedance exponentially increases with catheter size, influenced by the micropolar parameters and the coupling numbers, with micropolar fluids exhibiting higher impedance than that with Newtonian fluids. However, this study underscores the significant impact of catheterization on physiological fluid dynamics, notably increasing oesophageal impedance by two to threefold. This highlights the critical role of catheters in altering flow characteristics, emphasizing the need for a careful medical intervention during pre-diagnostic assessments.
Recent advancements and progress in development in chalcogenide (S, Se)-based thin films for high-performance photodetectors: a review
Authors: Alanazi Hamdah T A , Alzaidy Ghadah Abdulrahman
Published: July 2024

Scientific and technical communities often debate photodetection as a significant technology due to its unquestionable and extensive usage in business and research. Traditional bulk semiconductors like GaN, Si, and InGaAs are being used less and less for photodetection in industry because they aren’t mechanically stable or flexible enough, they have expensive substrates, and charge carriers can’t move around freely enough. Nonetheless, 2D materials such as transition-metal nitrides, chalcogenides, and carbides, in addition to graphene, are leading the path toward achieving more sophisticated results and surpassing the limitations imposed by traditional semiconductors. This is due to their exceptional electronic and mechanical properties, which include flexibility, adjustable bandgaps, high mobilities, and ample potential for constructing heterojunctions of chalcogenides-based thin films. Given the recent surge in photodetection research, the field has expanded significantly and requires a systematic compilation of pertinent scientific knowledge. A comprehensive study must address many aspects of chalcogenides-based thin film manufacturing strategies, assembly procedures, device integration, spectral properties, heterojunction potential, and future research prospects. This paper specifically examines the use of chalcogenides-based thin film materials in photodetection. These areas include solar-blind, visible, near-infrared, and broadband detectors. We have expanded our discussion to include photodetector performance parameters and how the latest chalcogenides-based thin films formed by combining ordinary semiconductors have resulted in high-performance UV, visible, and IR range photodetection. These materials have the potential to be used as photodetectors. Ultimately, we provide a comparative demonstration of the performance characteristics of photodetectors, offering a distinct assessment of the suitability of these materials for use in the advancement of next-generation photodetectors.
Construction of high activity electrocatalyst for alkaline hydrogen evolution by doping magnetic Fe3O4 with RuO2
Authors: Kou Xinrui , Qi Yiyi , Pang Haiyan , Tian Heyun , Luo Jie , Zhang Ke , Liu Xiao , Xu Guangri , Liu Hongling
Published: July 2024

The rational build of hydrogen evolution reaction (HER) electrocatalyst with low-cost, highly efficient, and excellent stability is the key to realizing the electrochemical decomposition of water. Herein, the optimal ratio between RuO2 and Fe3O4 for high-activity electrocatalysts (RuO2/Fe3O4 hybrid nanoparticles) was obtained by the microemulsion method. The morphology and structure characterization show uniform distribution (average particle size of ∼35.0 ± 5.1 nm) and high crystallinity of the RuO2/Fe3O4 hybrid nanoparticles. Compared to RuO2/Fe3O4 (2:1) and RuO2/Fe3O4 (1:2) samples, electrochemical tests show that RuO2/Fe3O4 (1:1) exhibit favorable HER catalytic activity (overpotential: 181 mV at 10 mA cm−2; Tafel slope: 130 mV dec−1) and stability (no obvious activity attenuation during the 20 h) in an alkaline medium. The mechanism analysis implies that the doping of Fe3O4 accelerated the electron transfer rate and thus increased HER activity via the results of electrochemical impedance spectroscopy (EIS) tests. Blending the appropriate amount of Fe3O4 into RuO2 can not only reduce the cost of electrocatalyst but also improve the activity of electrocatalytic HER, which is expected to give guidance for the development of low-cost, highly stable nanostructured electrocatalysts for electrochemical HER in alkaline electrolytes.
Exchange bias behavior in cobalt ferrite-cobalt oxide CoFe2O4/CoO nanocomposites for data storage applications
Authors: Shahzad Khuram , Abbasi Muhammad Ali , Jabeen Ayesha , Zaman Muhammad , Shehzad Umar , Rafe Muhammad Hassan
Published: July 2024

In this study cobalt ferrite-cobalt oxide CFO/CoO nanoparticles were synthesized using hydrothermal chemical method for studying the exchange bias (EB) phenomena, a key parameter for data storage applications. The structural analysis was carried out by Scanning electron microscopy (SEM), x-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS), which confirm formation of platelets like CFO/CoO nanoparticles with appropriate chemical composition of different elements with an average crystallite size of 15 nm. Magnetic study revealed the ferromagnetic behaviour of nanoparticles from (5 K–360 K) and blocking temperature has found to be above 360 K, which decreases nonmonotonically with increasing the applied field HFC. The field cool (FC) magnetic hystersis (MH) loop studies have revealed that the samples exhibit very large exchange bias effect. The values of exchange bias (HEB) is found to be maximum at low temperature and decreases with increasing temperature before vanishing at the blocking temperature. The aim of the study is to determine role of cooling field strength for the exchange bias in magnetically contrasted CFO/CoO nanoparticles suitable for data storage applications.
Effect of sliding speed and sliding distance on wear behavior of AZ31-B4C composite
Authors: Titarmare Vikram , Banerjee Sudip , Sahoo Prasanta
Published: July 2024

Emphasis of current research is to investigate the dry sliding behavior of AZ31 magnesium alloy and AZ31–1.5B4C magnesium metal matrix composites (MMCs) at varying sliding speeds and sliding distances. Magnesium alloy and composite are fabricated through ultrasonic assisted stir casting method. Optical microscope (OM), scanning electron microscopy (SEM), and energy dispersive x-ray analysis (EDAX) are used to characterize developed materials. Microhardness of all materials is measured using a Vickers microhardness tester. Wear-friction behavior is investigated in dry sliding mode using pin-on-disc tribometer at room temperature. Magnesium alloy and composite are tested over a range of sliding speeds (0.25–1.25 m s−1) and distances at a moderate normal load (20N). Wear morphology is finally investigated for composites and alloy under SEM and EDAX. SEM micrographs of as-cast AZ31-1.5B4C composite reveals uniform distribution of B4C particles with noticeable refinement in grain structure. EDAX spectra of AZ31-1.5B4C composite depict the presence of boron and carbon along with existing elements of AZ31 alloy. Microhardness has enhanced around 30% for Mg-MMC by incorporating 1.5 wt% B4C in AZ31 alloy. Furthermore, the use of B4C as reinforcement increases the density of the composite. Wear rate is reduced by around 20% and COF is reduced by around 25% for AZ31-1.5B4C composite compared to AZ31 alloy for all experimental conditions. Abrasion, oxidation, adhesion and delamination wear mechanisms are observed as dominant mechanism for varying sliding speeds and distances.
Influence of local defects in the generation of memory effect in Dy2Ti2O7 compound: Fe-doped study
Authors: Yadav Pramod K , Upadhyay Rajnikant , Kumar Rahul , Nukala Pavan , Upadhyay Chandan
Published: July 2024

The study of defect-induced effects in functional materials is high-priority research for the miniaturization of smart devices. To elucidate the influence of local defects stemming from intrinsic or extrinsic factors on the enigmatic behavior of cooperative spin dynamics, we investigated the Dy2-xFexTi2O7 compound within a narrow Fe substitution range (x = 0–0.15). Our experimental findings unequivocally demonstrate that the dynamic response of cooperative spins and the emergence of anomalous memory effect are intricately linked to local defects. Depending on the nature and dynamics of these defects, the dynamic response of cooperative spins undergoes alteration. Notably, observed anomalous effect becomes more pronounced in scenarios characterized by slower defect dynamics and when cooperative spins are further from equilibrium. The emergence and sensitivity of thermomagnetic hysteresis (memory effect) to cooperative spin dynamics and external stimuli underscore the richness of Dy2Ti2O7 as a material for captivating physics investigations.
An advance in the arithmetic of the Lie groups as an alternative to the forms of the Campbell-Baker-Hausdorff-Dynkin theorem
Authors: Kim Sunghyun , Liu Zhichen , Klemm Richard A
Published: July 2024

The exponential of an operator or matrix is widely used in quantum theory, but it sometimes can be a challenge to evaluate. For non-commutative operators X and Y, according to the Campbell-Baker-Hausdorff-Dynkin theorem, e
X+Y
is not equivalent to e
X
e
Y
, but is instead given by the well-known infinite series formula. For a Lie algebra of a basis of three operators {X, Y, Z}, such that [X, Y] = κ
Z for scalar κ and cyclic permutations, here it is proven that e
a
X+b
Y
is equivalent to e
p
Z
e
q
X
e−p
Z
for scalar p and q. Extensions for e
a
X+b
Y+c
Z
are also provided. This method is useful for the dynamics of atomic and molecular nuclear and electronic spins in constant and oscillatory transverse magnetic and electric fields.
Low energy electron scattering cross sections of cyanotriacetylene (HC7N) based on ab-initio R-matrix method
Authors: Vadhel Sagar , Vinodkumar P C , Vinodkumar Minaxi
Published: July 2024

Cyanotriacetylene (HC7N) is a linear unsaturated molecule detected in various regions of space. In this present study, we explored the quantum dynamics of low-energy electron collisions with linear cyanopolyyne molecule (HC7N) to identify the locations and structural features of their metastable negative ions (also known as transient negative ions). We employed the R-matrix method for handling low-energy electron scattering studies. To uncover trends among cyanopolyynes molecules, we have also incorporated results from Cyanoacetylene (HC3N) and Cyanodiacetylene (HC5N). Notably, we observed that the number of π* resonances increases and shifts to lower energies as the number of triple bonds increases in higher-order molecules. Our theoretical calculations contain elastic, differential, and momentum cross-sections in the elastic part. Additionally, we calculated excitation and ionization cross-sections in the inelastic regime. This comprehensive theoretical data on electron scattering will be valuable for understanding the molecular chemistry involving this interesting molecule.
Nonlocal advantage of quantum coherence under Garfinkle-Horowitz-Strominger dilation space-time
Authors: Ming Fei , Fang Bao-Long , Hu Xueyou , Yu Yang , Wang Dong
Published: July 2024

Nonlocal advantage of quantum coherence (NA-QC) is a relatively robust non-classical correlation and can be achieved by coherence complementary relations. In this work, we investigate NA-QC based on various coherence measures within the theoretical framework of a Garfinkle-Horowitz-Strominger dilation black hole. Interestingly, NA-QC exhibits monotonically decreasing evolutionary features with the growing dilation parameter in the physically accessible regions. Furthermore, the hierarchical relationship among NA-QC, quantum steerability and Bell-nonlocality is analyzed under the influence of Hawking radiation. It is shown that NA-QC is a subset of Bell-nonlocality and quantum steering is a superset of Bell-nonlocality. Additionally, to achieve more quantum resources, we propose a feasible physical scheme to control NA-QC by using optimal parity-time (

P
T

)-symmetric operations. The amount of NA-QC can be effectively enhanced in the certain time interval for the physical accessible state in the context of black hole. These results might play important roles for understanding quantum information theory under the curved space-time.
Examine the soliton solutions and characteristics analysis of the nonlinear evolution equations
Authors: Hossain A K M Kazi Sazzad , Akbar M Ali
Published: July 2024

The consistent and feasible enhanced

(

G

′

/
G
)

-expansion technique is applied to construct an assortment of fresh and universal soliton solutions to the two important nonlinear evolution equations. One of them is the Benjamin-Ono equation, which is a partial differential equation that describes the propagation of weakly nonlinear and weakly dispersive long waves in deep stratified fluids in one dimension. Another equation is the modified Benjamin-Bona-Mahony equation, which is a variant of the Benjamin-Bona-Mahony equation and is used to examine Rossby waves in rotating fluids as well as drift waves in plasma. In this study, we investigated the aforementioned equations and obtained sufficient soliton solutions, such as bell soliton, periodic and kink-shape soliton, singular and singular-kink soliton, and so on. All the solutions achieved have physical explanations, and plotting some 3D figures reveals the diverse physical configurations and characteristics. We also include a comparison of other’s solutions in the literature to our own, which validates our solutions. The solutions indicate that the mentioned method is adaptable, improved, and effective for other nonlinear evolution equations in mathematical physics.
Analysis of some newly constructed compact models in f(R, T) theory
Authors: Feng Yihu , Naseer Tayyab , Ashraf Asifa , Sofuoğlu Değer
Published: July 2024

In this paper, black hole solutions are developed within the framework of f(R, T) gravity through the minimal gravitational decoupling approach. By introducing a new source in the original isotropic matter distribution, the corresponding field equations acquire additional degrees of freedom. Applying the transformation on the radial metric function leads these equations to two distinct sets, each representing the influence of either the seed or additional source exclusively. In order to formulate the black hole solutions, the seed source is considered to be a vacuum, characterized by the Schwarzschild metric. To derive a viable solution for the second system, constraints are imposed on the metric potentials and energy-momentum tensor of the additional source. Three distinct solutions are graphically analyzed based on varying values of the decoupling parameter. The energy conditions are also plotted to determine the nature of the extra source. Finally, it is concluded that two of our three developed models agree with the asymptotic flatness criterion and energy bounds in this modified theory.
Enhancement of electrical and photo-electrical properties of P3HT:CrCl2 thin films for photo sensing applications
Authors: Mahdi Ali , Al-Saymari Furat A
Published: July 2024

In this work, doped and undoped P3HT thin films are prepared and deposited onto ITO interdigitated electrodes. To improve the optical and the electrical properties of the pure P3HT thin film, chromium(II) chloride was used as dopant material with three different weight percentage, 2.5%, 5%, 10%. Room-temperature current–voltage (I-V) characteristics of the samples were measured, showing an increase in the electrical current with increasing the dopant concentration. Under dark condition, the conductivity and resistivity of the pure P3HT thin films were enhanced by a factor of 5× as a result of doping the P3HT by 10 wt% of CrCl2. Under light intensity (50 mW cm−2) and at 10 V bias, the conductivity and resistivity obtained from P3HT:CrCl2 (10 wt%) thin films are 4.75 × 10−4 S cm−1 and ∼2 kΩ, respectively. These results exhibit an enhancement by a factor of ∼12× compared to those obtained from pure P3HT thin film. The current of the photo-sensors based on doped/undoped P3HT thin films are measured as a function of time under light intensity ranging from 0 to 50 mW cm−2 at 1 V bias, exhibiting high photo-response and good reproducibility. Three different wavelengths, white, green, and red were used as light sources to expose the photo-sensors. Under white light, photo-sensor based on P3HT:CrCl2(10 wt%) exhibit the highest values of the photo-responsivity and quantum efficiency, ∼23.3 mA W−1 and 5.8%, respectively, showing an enhancement by a factor of ∼ 11.5× compared to those obtained from the photo-sensor based on pure P3HT.
Generalization of Bernoulli polynomials to find optimal solution of fractional hematopoietic stem cells model
Authors: Avazzadeh Zakieh , Hassani Hossein , Ebadi Mohammad Javad , Bayati Eshkaftaki Ali , Katani Roghayeh , Rezvani Alireza
Published: July 2024

The study introduces a fractional mathematical model in the Caputo sense for hematopoietic stem cell-based therapy, utilizing generalized Bernoulli polynomials (GBPs) and operational matrices to solve a system of nonlinear equations. The significance of the study lies in the potential therapeutic applications of hematopoietic stem cells (HSCs), particularly in the context of HIV infection treatment, and the innovative use of GBPs and Lagrange multipliers in solving the fractional hematopoietic stem cells model (FHSCM). The aim of the study is to introduce an optimization algorithm for approximating the solution of the FHSCM using GBPs and Lagrange multipliers and to provide a comprehensive exploration of the mathematical techniques employed in this context. The research methodology involves formulating operational matrices for fractional derivatives of GBPs, conducting a convergence analysis of the proposed method, and demonstrating the accuracy of the method through numerical simulations. The major conclusion is the successful introduction of GBPs in the context of the FHSCM, featuring innovative control parameters and a novel optimization technique. The study also highlights the significance of the proposed method in providing accurate solutions for the FHSCM, thus contributing to the field of mathematical modeling in biological and medical research.
Optical soliton solution of the perturbed Biswas-Milovic equation having cubic-quintic-septic law nonlinearity in the presence of spatio-temporal and chromatic dispersion
Authors: Esen Handenur , Secer Aydin , Ozisik Muslum , Bayram Mustafa
Published: July 2024

In this manuscript, we investigate the analytical and soliton solutions of the cubic-quintic-septic law for the perturbed Biswas-Milovic equation, considering spatio-temporal and chromatic dispersions. The perturbed Biswas-Milovic equation with the spatio-temporal and chromatic dispersion terms provides a comprehensive study for describing nonlinear optical wave propagation in optical fiber. We use the wave transformation to reduce the main equation to a nonlinear ordinary differential equation. The transformation of the original equation into a more simplified form aims to attain a more profound comprehension of the fundamental dynamics of the system. We retrieve the analytical solutions of the presented model by implementing the new Kudryashov technique and a subversion of the new extended auxiliary equation approach. Besides, bright, singular, and V-shape soliton structures are represented. By employing powerful analytical techniques, we systematically derive a wide range of soliton solutions. This approach successfully captures diverse soliton types highlighting the novelty of applying the new Kudryashov technique and a subversion of the new extended auxiliary equation method to this complex model. Moreover, we analyze the soliton behavior influenced by various parameters. The analysis of the parameter influences reveals the complicated relationship governing the dynamics of the perturbed Biswas-Milovic model. Furthermore, this manuscript includes the modulation instability analysis for the presented model. Conducting modulation instability analysis for the presented equation enhances our understanding of the system’s stability and dynamics.
Power spectra and circular polarization of primordial gravitational waves with parity and Lorentz violations
Authors: Li Tian-Chen , Zhu Tao , Zhao Wen , Wang Anzhong
Published: July 2024

The violations of parity and Lorentz symmetries in gravity can change the propagating properties of gravitational waves (GWs) in the cosmological background, which can arise from a large number of parity- and Lorentz-violating theories. In this paper, through a systematic parametrization for characterizing possible derivations from the standard GW propagation in general relativity, we study both the parity- and Lorentz-violating effects on the power spectra and the polarization of the primordial gravitational waves (PGWs) during the slow-roll inflation. To this end, we calculate explicitly the power spectrum and the corresponding circular polarization of the PGWs analytically by using the uniform asymptotic approximation. It is shown that the new contributions to power spectra contain two parts, one from the parity-violating terms and the other from the Lorentz-violating terms. While the Lorentz-violating terms can only affect the overall amplitudes of PGWs, the parity-violating terms induce nonzero circular polarization of PGWs, i.e., the left-hand and right-hand polarization modes of GWs have different amplitudes.
A closer look at the electromagnetic signatures of Bethe-Heitler pair production process in blazars
Authors: Karavola D. , Petropoulou M.
Published: July 2024

The “twin birth” of a positron and an electron by a photon in the presence of a nucleus, known as Bethe-Heitler pair production, is a key process in astroparticle physics. The Bethe-Heitler process offers a way of channeling energy stored in a population of relativistic protons (or nuclei) to relativistic pairs with extended distributions. Contrary to accelerated leptons, whose maximum energy is limited by radiative losses, the maximal energy of pairs is determined by the kinematics of the process and can be as high as the parent proton energy. We take a closer look at the features of the injected pair distribution, and provide a novel empirical function that describes the spectrum of pairs produced by interactions of single-energy protons with single-energy photons. The function is the kernel of the Bethe-Heitler pair production spectrum that replaces a double numerical integration involving the complex differential cross section of the process, and can be easily implemented in numerical codes. We further examine under which conditions Bethe-Heitler pairs produced in blazar jets can emit γ-ray photons via synchrotron radiation, thus providing an alternative to the inverse Compton scattering process for high-energy emission in jetted active galactic nuclei. For this purpose, we create 36 numerical models using the code ATHEνA optimized so that the Bethe-Heitler synchrotron emission dominates their γ-ray emission.
After taking into consideration the broadband spectral characteristics of the source, the jet energetics, and the properties of radiation fields present in the blazar environment, we conclude that γ-rays in high-synchrotron-peaked blazars are unlikely to be produced by Bethe-Heitler pairs, because the emitting region is found to be opaque in photon-photon pair production at photon energies ≳ 10 GeV. On the contrary, γ-ray spectra of low-synchrotron-peaked blazars may arise from Bethe-Heitler pairs in regions of the jet with typical transverse size ∼ 1015 – 1016 cm and co-moving magnetic field 50 – 500 G. For such cases, an external thermal target photon field with temperatures T ∼ 4 · 102– 6 · 103 K is needed. The latter values could point to the dusty torus of the AGN. Interestingly, a Bethe-Heitler-dominated high-energy component is mostly found in models of intermediate-synchrotron peaked blazars, for a wide range of magnetic fields and source radii.
Thermal fluctuations, deflection angle, and greybody factor of a high-dimensional Schwarzschild black hole in scalar–tensor–vector gravity
Authors: Li Qian , Zhang Yu , Li Qi-Quan , Sun Qi
Published: July 2024

In this study, we examined the thermal fluctuations, deflection angle, and greybody factor of a high-dimensional Schwarzschild black hole in scalar–tensor–vector gravity (STVG). We calculated some thermodynamic quantities related to the correction of the black hole entropy caused by thermal fluctuations and discussed the effect of the correction parameters on these quantities. By analyzing the changes in the corrected specific heat, we found that thermal fluctuations made the small black hole more stable. It is worth noting that the STVG parameter did not affect the thermodynamic stability of this black hole. Additionally, by utilizing the Gauss–Bonnet theorem, the deflection angle was obtained in the weak field limit, and the effects of the two parameters on the results were visualized. Finally, we calculated the bounds on the greybody factor of a massless scalar field. We observed that as the STVG parameter around the black hole increased, the weak deflection angle became larger, and more scalar particles can reach infinity. However, the spacetime dimension has the opposite effect on the STVG parameter on the weak deflection angle and greybody factor.
Ultra-broadband and wide-angle reflective terahertz polarization conversion metasurface based on topological optimization
Authors: Zhang 张 Ya-Jie 亚杰 , Li 李 Chao-Long 潮龙 , Luan 栾 Jia-Qi 迦淇 , Zhao 赵 Ming 茗 , Gao 郜 Ding-Shan 定山 , Li 李 Pei-Li 培丽
Published: July 2024

Terahertz polarization conversion devices have significant potential applications in various fields such as terahertz imaging and spectroscopy. In this paper, we utilize genetic algorithms to topologically optimize the metasurface unit cells and design a reflective linear polarization conversion metasurface with ultra-broadband and wide-angle characteristics. By partitioning the metallic pattern layer into quadrants, the encoding length is effectively reduced, resulting in a shorter optimization time. The research results indicate that the converter possesses a polarization conversion efficiency ratio higher than 90% and a relative bandwidth ratio of 125% in a range of 0.231–0.995 THz. Meanwhile, it can maintain excellent polarization conversion properties when the incident angle of terahertz waves is less than 45° and the polarization angle is less than 15°, demonstrating excellent practicality. New insights are provided for the design of terahertz wide-angle ultra-wideband polarization conversion devices, and the proposed metasurfce has potential applications in terahertz polarization imaging, spectroscopy and communication fields.