bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the effect of natural fractures and temperature on the wormhole morphology formed by two-phase acidizing in carbonate rocks
Authors: Chang Tai , Jiang Youshi , Li Yongming , Chen Xiyu , Kang Xin , Mo Weiren
Published: August 2024

The simulation of a two-phase acidizing process coupled with thermal–chemical–fracturing is a complex task, given the presence of natural fractures in carbonate rocks and the influence of temperature on the acid–rock reaction. In this work, we introduce a mixed computational strategy combining the operator splitting and the Newton iteration built upon the embedded discrete fracture model. This innovative strategy is designed to tackle nonlinear problems arising from the coupling of multiphysics fields. The porosity improved region within rock is divided into three parts: the high (H), medium (M), and low (L) efficiency regions, aimed at clearly assessing the impact of various physical fields on acidizing efficiency. The results show that the wormhole morphology is determined by the H and M regions, and the L region determines the acidizing efficiency. The oil in the rock can have a “sealing effect” on the acid, improving the acidizing efficiency. For the large fracture aperture, the wormhole morphology is predominantly influenced by fractures, with the influence diminishing as the aperture decreases. At small apertures, fractures exhibit minimal impact on the morphology. While increasing injection temperature may not significantly alter the wormhole morphology, it can enhance acidizing efficiency. The morphology of wormholes is highly sensitive to multiphase interactions, fractures, and temperature variations. The proposed hybrid computational strategy effectively addresses multiphysics field challenges in two-phase acidizing.
Direct numerical simulation study on convective heat transfer of two tandem permeable square cylinders
Authors: Duong Viet Anh , Nguyen Van Sang , Nguyen Quoc Khanh , Nguyen Tien Thanh , Duong Viet Dung
Published: August 2024

This study focuses on two-dimensional heat transfer and unsteady flow past two tandem heated porous square cylinders using lattice Boltzmann method combined with block-structured topology-confined mesh refinement. The effects of the Reynolds number (30≤Re≤150), the Darcy number (10−5≤Da≤10−2), and spacing ratio (1.5≤L/D≤5, where L and D are distance of two adjacent cylinder centers and square cylinder length, respectively) are investigated. The intended analysis links hydrodynamic and heat transfer coefficients and wake structures in parameter space of Re−Da−L/D to fluid mechanics. For upstream cylinder, drag coefficients decrease with a reduction of Da and range of Re≥100, while wake length increases with an increment of L/D ratio at the same range of Re. Time-averaged normalized velocity increases at higher permeability levels. A significant augmentation in a time-averaged Nusselt number is reported for an increase in Da and full L/D range. For downstream cylinder, the interaction of fluid vortices in the gap between the cylinders affects the flow pattern, causing irregularities in the drag coefficient variation. The impacts of L/D on the wake length is more obvious than that of Da. Both the wake length and time-averaged Nusselt number values are proportional to an increase in L/D. Consequently, all the investigated results of the upstream cylinder are significantly altered from those of the downstream cylinder due to the shadowing effect of the upstream cylinder.
Freezing non-radiative recombination in high-performance CsPbBr3 single crystal x-ray detector
Authors: Zhao Xiao , Wang Shimao , Song Yanan , Aoki Toru , Gnatyuk Volodymyr , You Libing , Deng Zanhong , Tao Ruhua , Fang Xiaodong , Meng Gang
Published: August 2024

Though CsPbBr3 single crystals (SCs) possess intriguing photoelectronic properties for x/γ-ray detection, the serious ion migration and high thermally activated carrier concentration at room temperature (RT), typically associated with defect states in CsPbBr3 crystals, result in a high dark current and drift of baseline, hindering their potential applications. In this investigation, liquid nitrogen cooling is proposed to freeze deep-level defects in CsPbBr3 SCs, thereby suppressing the ion migrations and decreasing the thermally excited carrier concentration. Utilizing photoluminescence (PL) and time-resolved PL spectra, coupled with theoretical models for photoexcitation and photoemission processes, the freezing of deep-level defects at liquid nitrogen temperature (LNT) is confirmed, which is conducive to decreasing non-radiative recombination. At LNT, the CsPbBr3 SC exhibits a higher resistivity of 4.95 × 1011 Ω cm and a higher mobility–lifetime product of 9.54 × 10−3 cm2 V−1, in contrast to the RT values of 3.86 × 109 Ω cm and 3.67 × 10−3 cm2 V−1, respectively. Furthermore, the x-ray detector at LNT exhibits a high sensitivity of 9309 μC Gyair−1 cm−2 and an impressively low detection limit of 0.054 nGy s−1, which offers a route for obtaining highly sensitive x-ray detectors for applications including ultra-low dose radiation imaging.
Frequency synaptic behavior of ZnO/HfZrO memristor with pulsed stimuli
Authors: Lu Jie , Xiang Zeyang , Wang Kexiang , Wang Ziyu , Shi Si , Liu Zuming , Chen Xiran , Hu Xinyu , Jiang Ran
Published: August 2024

The synaptic response of ZnO/HfZrO memristor devices to electrical stimuli was studied. It was found that the frequency of the stimuli affects the rate of current increase, which can be explained by the cluster state of oxygen vacancies at the interface of ZnO/HfZrO. This variation in the synaptic response due to stimulus frequency was consistent with the dynamic adjustment of tolerance thresholds observed in the human brain's response to environmental stimuli. The rate of change in current, representing the sensitivity to stimuli, mirrors the biological nervous system's reaction to environmental changes, such as Ebbinghaus forgetting behavior. Additionally, frequent irregular changes in stimuli lead to a reduced lifespan of the devices, highly resembling the biological lifetime-injure on frequent environmental fluctuations. These findings highlight the memristors' significant similarity to biological nerves in response to stimuli, confirming their tremendous potential in bionic synaptic simulation applications.
Active disturbance rejection control for piezoelectric cantilever beam with time delay
Authors: Zhang Shuowen , Wang Gang
Published: August 2024

This Letter presents an active control method for the vibration of piezoelectric structures. First, a controller based on nonlinear extended state observer is designed to improve the disturbance rejection capability of the vibration structure. Additionally, an improved nonlinear active disturbance rejection control (IMNADRC) method is combined with Smith predictor for time delay compensation, resulting in Smith predictor-based IMNADRC. Finally, numerical simulations and experiments are carried out for active vibration suppression of piezoelectric beam under fixed harmonic excitation and variable harmonic excitation, respectively. The results show that the proposed method has good control effect on structural vibration suppression and is highly adaptable to various external excitations.
Origin of the anisotropic Beer–Lambert law from dichroism and birefringence in
β
-Ga2O3
Authors: Adnan Md Mohsinur Rahman , Schubert Mathias , Myers Roberto C.
Published: August 2024

The anisotropic optical absorption edge of β-Ga2O3 follows a modified Beer–Lambert law having two effective absorption coefficients. The absorption coefficient of linearly polarized light reduces to the least absorbing direction beyond a critical penetration depth, which itself depends on polarization and wavelength. To understand this behavior, a Stokes vector analysis is performed to track the polarization state as a function of depth. The weakening of the absorption coefficient is associated with a gradual shift of linear polarization to the least absorbing crystallographic direction in the plane, which is along the a-exciton within the (010) plane or along the b-exciton in the (001) plane. We show that strong linear dichroism near the optical absorption edge causes this shift in β-Ga2O3, which arises from the anisotropy and spectral splitting of the physical absorbers, i.e., excitons. The linear polarization shift is accompanied by a variation in the ellipticity due to the birefringence of β-Ga2O3. Analysis of the phase relationship between the incoming electric field to that at a certain depth reveals the phase speed as an effective refractive index, which varies along different crystallographic directions. The critical penetration depth is shown to be correlated with the depth at which the ellipticity is maximal. Thus, the anisotropic Beer–Lambert law arises from the interplay of both the dichroic and birefringent properties of β-Ga2O3.
Inflation and dark matter from the low entropy hypothesis and modeling mechanism of modified gravity
Authors: Liu Jackie C H
Published: August 2024

The hypothesis of low entropy in the initial state of the Universe usually explains the observed entropy increase is in only one time direction: the thermodynamic arrow of time. The Hamiltonian formalism is commonly used in the context of general relativity. The set of Lagrange multipliers are introduced in the formalism, and they are corresponding to the Hamiltonian constraints which are written in terms of ‘weak equality’—the equality is satisfied if the constraints hold. Follow the low-entropy hypothesis, we postulate a modeling mechanism—a weak equality (of modeling) that holds only on the subspace of the theory space of physical models defined by some modeling constraints. By applying the modeling mechanism, we obtain a specific model of modified gravity under specific modeling conditions. We derive a novel equation of modeling from the mechanism, that describes how different gravitational models emerge. The solution of the modeling equation naturally turns out to be the model of R
2-gravity (with additional terms) if ordinary matter is negligible. We also found that this mechanism leads to two models: large-field inflation and wave-like dark matter (DM). Interestingly, the wave-like DM model is supported by the most recent observations of Einstein rings.
Angle-insensitive perfect light transmission and absorption in one-dimensional photonic crystal heterostructures
Authors: Wei Guochao , Wang Beibei , Du Kang , Zhang Bohan , Han Weijia , Zhu Wei , Wang Shengxiang
Published: August 2024

Perfect light transmission in metamaterials typically experiences a frequency shift as the incident angle of the wave increases, limiting their applicability across wide angles. One-dimensional photonic crystal heterostructures, with elliptic-shaped equi-frequency contours, exhibit angle-in sensitive properties. However, an inevitable blue shift in the optical response still occurs as the incident angle increases. In this work, we present two photonic crystal heterostructures, one of which incorporates the optical phase-change material Sb2S3. By joining two heterostructures with distinct Zak phases, we achieve perfect light transmission. Specifically, as incident angle of wave increases, the transmission peak can be strictly maintained without a frequency shift by tuning the phase (refractive index) of Sb2S3. Moreover, by combining the heterostructures with a thin silver film, we demonstrate a Tamm plasmon polariton mode with angle-insensitive properties, facilitating angle-tolerant light absorption. Our work offers an innovative approach to designing highly angle-tolerant and tunable devices, which could be applied in various fields such as telecommunications, sensing, and imaging systems, where maintaining performance across a wide range of incident angles is crucial.
Incremental effects of near-atmospheric-pressure low-temperature air plasma jet irradiation on polyphenol content in harvested onions
Authors: Kawakami Retsuo , Mukai Rie , Matsumura Takumi , Fujii Haruki , Jinbo Kurumi , Sogawa Ryutaro , Hashimura Nene , Ohashi Koichi
Published: August 2024

We present a new food processing method to increase the content of polyphenols, which are a type of health-promoting food component, in harvested onions using atmospheric-pressure low-temperature plasma technologies. Harvested onions were locally irradiated for different times with a low-temperature air plasma jet generated near atmospheric pressure and stored in the dark for various periods. The plasma-irradiated area was 7 mm2. The plasma irradiation was performed without removing the onion peel. After storage following plasma irradiation, the onion was peeled and cut into the outer, middle, and inner parts, analysing polyphenol content at each edible onion part, namely the bulb. The polyphenol content in the onions irradiated for 30 min and stored for 3 d increased over that of unirradiated onions stored for the same period. This increase occurred regardless of the bulb parts. Neither the plasma-irradiated onions without storage nor the air gas-irradiated onions without air plasma irradiation exhibited a higher polyphenol content. In particular, quercetin aglycone, quercetin 4′-O-glucoside, quercetin 3-O-glucoside, and quercetin 3,4′-O-glucoside were increased in the polyphenol content, contributing to an increase in the antioxidative activity. NO3
− and NO2
− were introduced into water under an onion peel by air plasma irradiation for 30 min and decreased after 3 d of storage but remained. However, no H2O2 was introduced. The plasma-introduced NO3
− was distributed throughout the onion owing to the plasmodesmata serving as channels for cell-to-cell transports of molecules. These results suggest that the increased polyphenol content originates from the transcriptional factors acting in stress responses to the plasma-introduced NO3
− and NO2
−, not the electric field-induced electroporation, in onion cells. The present study provides valuable insights into interactions between low-temperature air plasma jets and onion cells.
A gear fault diagnosis method based on reactive power and semi-supervised learning
Authors: Liang Guangyu , Li Feng , Pang Xinyu , Zhang Bowen , Yang Peng
Published: August 2024

In gearbox gear fault diagnosis based on motor current signals, the gear fault characteristic frequency component is often overshadowed by the fundamental frequency component of the current. In addition, the complex working conditions during actual production and use make it difficult to collect gear operation monitoring data containing labeled feature information. To address the above problems, a semi-supervised learning method based on reactive power signals is proposed for gear fault diagnosis of gearboxes. First, the method utilizes the Hilbert transform to process the current signal of the drive motor in the mechanical system, from which the reactive power is constructed. Then, the reactive power signal is analyzed by spectral analysis as a basis for gear fault diagnosis. Subsequently, the GAF-CNN-MTDL(Gramian angular field—convolutional neural network-mean teacher deep learning) fault diagnosis model is proposed to convert the reactive power signal into a two-dimensional image by using the GAF, and the semi-supervised training method of the average teacher is applied to input the fault dataset into the gear fault diagnosis model which is based on the CNN as the main backbone after the fault dataset has been divided into the labeled and the unlabeled dataset in accordance with a certain ratio. Finally, the gear fault dataset is used for method validation. The experimental outcomes demonstrate the method’s proficiency in effectively emphasizing the fault feature information pertaining to the gear part, and the introduced GAF-CNN-MTDL fault diagnosis model enables the utilization of a minimal number of labeled samples to achieve highly accurate gear fault diagnosis.
Cellulose acetate membranes loaded with WO3/g-C3N4: a synergistic approach for effective photocatalysis
Authors: Sasikala Velusamy , Sarala Sakarapani , Karthik Palani , Prakash Natarajan , Mukkannan Azhagurajan
Published: August 2024

The objective of this study is to develop an efficient, easily recoverable membrane-based photocatalyst for removing organic pollutants from aqueous solutions. This study documents the effective synthesis of a novel composite photocatalyst comprising WO3/g-C3N4 (WCN) loaded onto cellulose acetate (CA). The physicochemical properties of the synthesized nanocomposites were validated using a range of techniques, including Fourier transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy, and UV–visible diffuse reflectance spectroscopy. SEM analysis revealed that the WCN particles exhibited a well-decorated arrangement on the CA surface in the form of spherical particles. The successfully synthesized film was utilized as a potential adsorbent for removing organic pollutants such as Rhodamine B (Rh-B) and Methylene blue (MB) from aqueous solutions under UV light illumination. The results showcased the significant potential of the WCN@CA nanocomposite, achieving a remarkable 83% and 85% efficiency in eliminating Rh-B and MB. The pseudo-first-order kinetic models were found to be appropriate for both dye adsorption onto the WCN@CA nanocomposite. The WCN@CA catalyst, capable of being reused five times without significant loss of efficiency, shows great potential for decomposing toxic organic pollutants. The novelty of this work lies in the innovative combination of WCN with CA, resulting in a highly efficient and reusable photocatalyst for environmental remediation.
4D printing of magneto-responsive shape memory nano-composite for stents
Authors: Kim Young Bin , Song Heechan , Kim Suji , Chun Heoung-Jae
Published: August 2024

This study focuses on the 4D printing simulation technique of magneto-responsive shape memory nanocomposite stents. A nanocomposite material was created by incorporating polycaprolactone, a shape memory material, with Fe3O4 to enhance magnetic responsiveness and stiffness. Tensile tests were conducted, and the material properties were applied to finite element analysis. Shape memory experiments were also performed to measure the temperature at which shape memory progression occurs due to magnetic response. In the 4D printing simulation, different coefficients of thermal expansion and the measured temperatures were reflected in the sections where shape memory is activated to implement shape memory behavior. The specimen simulation confirmed shape memory behavior progressing from 145 degrees to 3 degrees, while the stent simulation demonstrated satisfactory expansion to a radius of 3 mm. This study proposes a controllable method for implementing shape memory considering temperatures induced by magnetic response, showing potential for various medical device applications.
Double-layer metasurface for blocking the fundamental SH wave
Authors: Miao Hongchen , Cao Xi , Fu Mingtao
Published: August 2024

This work introduces a double-layer metasurface to isolate the fundamental shear horizontal wave (SH0 wave). The metasurface is designed to split the SH0 wave source into two parts and then manipulate the two waves to be out of phase and have equal amplitude upon reaching the end of the metasurface. This results in interference cancellation, effectively blocking the propagation of SH0 waves into the protected zone. Firstly, the metasurface is designed theoretically, utilizing rectangular strips to constitute the substructure. Subsequently, finite element simulations are conducted to verify the correctness of the theoretical design. Finally, the metasurface is fabricated using 3D printing, and its performance is evaluated through experiments. The results indicate that the metasurface can function as a cage for SH0 waves, trapping different types of SH0 waves located at any position within the cage. Furthermore, when the source of SH0 waves is positioned outside the cage, the metasurface can effectively impede their propagation into the interior region of the cage. The proposed double-layer metasurface provides a simple approach to blocking SH0 waves, which may have potential applications in practical engineering.
A new hyperchaotic system: circuit realization, nonlinear analysis and synchronization control
Authors: Mobayen Saleh , Mostafaee Javad , Alattas Khalid A , Ke Ming-Ta , Hsueh Ya-Hsin , Zhilenkov Anton
Published: August 2024

This paper presents a novel seven-dimensional nonlinear hyperchaotic system characterized by a minimal number of nonlinear terms and variables, yet exhibiting high complexity. Standard nonlinear analysis is conducted to unveil the system’s intricacies, emphasizing its notable feature of possessing four to five Lyapunov exponents in certain intervals, signifying its volatility and complexity. Hyperchaotic synchronization is explored using a novel nonsingular terminal sliding control design, effectively achieving synchronization between two hyperchaotic master systems and a hyperchaotic slave system within finite time while mitigating the chattering phenomenon. Practical evaluations through orbital analysis, numerical simulations, and practical implementations further substantiate the efficacy and performance of the proposed system. This study contributes to the advancement of chaotic and hyperchaotic systems, particularly those with dimensions exceeding 5D, offering insights into synchronization techniques and practical applications in engineering and other scientific disciplines.
Scattering of e∓ in beryllium isonuclear series: cross sections and transport characteristics
Authors: Shorifuddoza M , Ragimkhanov G B , Khalikova Z R , Das Pretam K , Watabe H , Fazlul Haque A K , Alfaz Uddin M
Published: August 2024

The elastic scattering of electrons and positrons by beryllium atoms and its isonuclear ion states is described in this paper in terms of differential and various angle integrated cross sections. For this element, the critical minima in the elastic differential cross sections and the optimum spin polarization sites are found. These calculations are performed using the Dirac partial wave analysis (DPWA) and a projectile-target modified complex optical model potential. Further, the Monte Carlo method is used to calculate the transport characteristics of electrons in a mixture of inert gas (He, Ar) and beryllium vapor for electric field values E/N = 1-100 Td, taking into account inelastic collisions. We studied the effect of metal vapor concentration on drift velocity, average electron energy, diffusion and mobility coefficients. Finally, we investigated the effect of beryllium vapor on the electron energy distribution function in the inert gas. On comparing present work with existing theoretical calculation, a reasonable agreement is observed.
A review of molecular dynamic simulations to study the effect of helium bubble formation in metal crystals
Authors: Sharma Saurabh S , Parashar Avinash
Published: August 2024

Nuclear power has the potential to replace traditional energy resources; however, the challenges associated with nuclear energy need to be addressed. The sustainable growth of nuclear power requires extensive studies to ensure a safer reactor and auxiliary structures lifecycle. This article aims to review the challenges associated with investigating the effect of irradiation on the thermo-mechanical behaviour of nuclear materials. Article has presented a comprehensive review of the atomistic simulations to investigate the impact of helium bubbles (generates from transmutation) on nuclear materials. The hazards associated with handling the irradiated samples of nuclear reactors have provided the impetus for developing computational models in the framework of atomistic environments. The temporal and spatial scale associated with irradiation-induced defects can be easily created in molecular dynamics-based simulations. This review article compiled force fields employed to simulate the interatomic interaction in metals in conjunction with helium bubble.
Impact of gravity on the performance of multi-inlets and multi-outlets valveless diaphragm micropumps
Authors: Gavali Sachin R , Pawar Dr. Prashant M
Published: August 2024

The influence of gravity plays a crucial role in micropumps’ fluid dynamics. Gravitational forces have an intricate effect on the fluid flow of the micropump. Understanding gravity’s influence on micropump fluid dynamics is critical for improving the fine design features and operational efficacy of the microscale pumping systems. This study conducted thorough a numerical analysis on the Single Inlet Double Outlet Diaphragm (SIDOD) micropump and the Double Inlet Single Outlet Diaphragm (DISOD) micropump to determine how gravity influences the performance. In this research, the optimal frequency is identified as 3 Hz. At this frequency, the SIDOD flow rate increases from 313 μl min−1 without gravity to 327.77 μl min−1 with gravity, marking an increase of 4.77%. Similarly, the DISOD flow rate rises from 177.78 μl min−1 without gravity to 184 μl min−1 with gravity, reflecting an approximate 3.56% increase. A comprehensive understanding of gravity impact is crucial for aerospace applications, where micropumps may operate under fluctuating gravitational conditions. The potential applications of micropumps in medical devices, particularly drug delivery systems, experience gravitational variations.
Genuine entanglement detection via projection map in multipartite systems
Authors: Mallick Bivas , Nandi Sumit
Published: August 2024

We present a formalism to detect genuine multipartite entanglement by considering projection map which is a positive but not completely positive map. Projection map has been motivated by the no-pancake theorem which repudiates the existence of a quantum operation that maps the Bloch sphere onto a disk along its equator. The not-complete positivity feature of projection map is explored to investigate genuine multipartite entanglement in arbitrary N-qubit quantum systems. Our proposed framework can detect some important classes of genuinely entangled states in tripartite and quadripartite scenarios. We provide illustrative example to show the efficacy of our formalism to detect a class of tripartite PPT bound entangled states. Finally, we construct a suitable witness operator based on projection map to certify genuine tripartite entanglement, which is likely to be feasible experimentally.
Unveiling the mass-loading effect on the electrochemical performance of Mn3O4 thin film electrodes: a combined computational and experimental study
Authors: A Pramitha , Hegde Shreeganesh Subraya , Ramachandra Bhat Badekai , Yadav K Chandrika , Chakraborty Shamik , Ravikumar Abhilash , George Sajan D , Sudhakar Y N , Y Raviprakash
Published: August 2024

The remarkable storage performance of manganese oxide (Mn3O4) makes it an appealing option for use as electrodes in electrochemical capacitors. However, the storage kinetics were significantly influenced by the mass loading of the electrode. Herein, we have inspected the dependency of mass loading on the storage performance of the spray pyrolyzed Mn3O4 thin film electrodes along with the correlation of structural and morphological characteristics. X-ray diffraction and Raman spectroscopic studies proven the formation of spinel Mn3O4 with a tetragonal structure. Morphological analysis revealed that all films exhibited fibrous structures with interconnected patterns at higher mass loadings. Moreover, the surface roughness and wettability of the electrode surface were influenced by variations in mass loading. Notably, thin-film electrode with a mass loading of 0.4 mg cm−2 exhibited the highest specific capacitance value of 168 F g−1 at 5 mV s−1 in a three-electrode system. Further, electrochemical impedance spectroscopic studies showed that there were noticeable changes in the capacitive behaviour of the electrode with respect to variations in mass loading. Moreover, the Dunn approach was employed to differentiate the underlying storage mechanism of the Mn3O4 electrode. Additionally, first-principles Density Functional Theory (DFT) studies were carried out in connection with the experimental study to comprehend the structure and electronic band structure of Mn3O4. This study underscores the critical importance of mass loading for enhancing the storage performance of Mn3O4 thin-film electrodes.
Electronic structure and phonon transport properties of HfSe2 under in-plane strain and finite temperature
Authors: Li Wei , Xue Feng-ning , Zhao Peng-bo , Lu Yong
Published: August 2024

The electronic structure and phonon transport properties of HfSe2 under different in-plane strains at finite temperatures are systematically investigated by combining first-principles calculations with machine learning force field molecular dynamics simulations. Within a strain range of -3% to 3%, the electronic band gap value of HfSe2 varies between 0.39 and 0.87 eV. Under compressive strain, the conduction band minimum moves towards the Fermi level, with the distribution of electrons near the valence band maximum becoming more delocalized. This will reduce the scattering of electrons during the transport process, helping to improve the carrier mobility. Under tensile strain, the localization of the density of states near the valence band maximum is strengthened, accompanied by enhanced metallic properties of the Hf-Se bonds, which facilitates the enhancement of the thermoelectric power factor. Both compressive and tensile strains intensify the coupling of phonon normal modes with phonon scattering, and elevating the temperature amplifies this impact. The anharmonicity-induced reduction in phonon frequencies is especially pronounced for modes in the vicinity of the Debye frequency. This not only curtails the phonon lifetimes but also diminishes the lattice thermal conductivity through the enhancement of vibrational coupling among optical branches and the reduction of the group velocity in acoustic branches. These results demonstrate the synergistic effects of strain and temperature on the electronic structure and phonon transport of HfSe2.
Synthesis and study of nonlinear optical properties of an enaminone derived from dibenzoylmethane and N,N-diethylaminoaniline
Authors: Elias Rita S , Hassan Qusay M A , Saeed Bahjat A , Sultan H A , Hansen Poul Erik , Emshary C A
Published: August 2024

The compound, (Z)-3-((4-(diethylamino)phenyl)amino)-1,3-diphenylprop-2-en-1-one, is synthesized by the reaction of dibenzoylmethane and 4-N,N-diethylaniline. The relative stabilities of the possible tautomers of the molecule are studied via the DFT B3LYP-D3BJ, CAM-B3LYP, M062X, and ωB97XD functionals in conjunction with the 6-311++G(d,p) basis set. The results showed that the enaminone tautomer with the intramolecularly hydrogen bonded chelated ring is the most stable. This is further confirmed by the Car–Parrinello MD calculations in the gas phase as well as the NCI analysis. The electronic spectrum is calculated by the TD DFT B3LYP/c-pVDZ level in ethanol, and the hole–electron analysis is carried out for the interpretation of the bands, which revealed that the longest one at 430 nm is of charge transfer origin while the others are of local transition origin. Atoms-in-molecules calculations in several media and levels of theory predicted that the ρBCP at the hydrogen bond in the gas phase to be 0.03791–0.04255 e/a0
3 which is a characteristic of a medium strong hydrogen bond. Researchers investigated the enaminone’s nonlinear optical (NLO) characteristics when it was exposed to a low power (<1 Watt), single fundamental transverse mode laser beam at 473 nm. By using diffraction patterns (DPs) and Z-scan methods, we calculated the nonlinear refractive index (NLRI) of the enaminone up to 4.597 × 10−11 m2 W−1 using DPs. The resulting DPs are numerically investigated using the Fraunhofer (F.) approximation and the Fresnel-Kirchhoff (F.K.) diffraction integral, showing excellent agreement with experimental findings. We successfully explored all-optical switching (AOS) in enaminone using two laser beams.
Analysis of electroviscous effects in electrolyte liquid flow through a heterogeneously charged uniform microfluidic device
Authors: Dhakar Jitendra , Bharti Ram Prakash
Published: August 2024

Charge-heterogeneity (i.e., surface charge variation in the axial direction of the device) introduces non-uniformity in flow characteristics in the microfluidic device. Thus, it can be used for controlling practical microfluidic applications, such as mixing, mass, and heat transfer processes. This study has numerically investigated the charge-heterogeneity effects in the electroviscous (EV) flow of symmetric (1:1) electrolyte liquid through a uniform slit microfluidic device. The Poisson’s, Nernst-Planck (N-P), and Navier–Stokes (N-S) equations are numerically solved using the finite element method (FEM) to obtain the flow fields, such as total electrical potential (U), excess charge (n
*), induced electric field strength (E
x), and pressure (P) fields for following ranges of governing parameters: inverse Debye length (2 ≤ K ≤ 20), surface charge density (4 ≤ S
1 ≤ 16), and surface charge-heterogeneity ratio (0 ≤ S
rh ≤ 2). Results have shown that the total potential (∣ΔU∣) and pressure (∣ΔP∣) drop maximally increase by 99.09% (from 0.1413 to 0.2812) (at K = 20, S
1 = 4) and 12.77% (from 5.4132 to 6.1045) (at K = 2, S
1 = 8), respectively with overall charge-heterogeneity (0 ≤ S
rh ≤ 2). Electroviscous correction factor (Y, i.e., ratio of effective to physical viscosity) maximally enhances by 12.77% (from 1.2040 to 1.3577) (at K = 2, S
1 = 8), 40.98% (from 1.0026 to 1.4135) (at S
1 = 16, S
rh = 1.50), and 41.35% (from 1 to 1.4135) (at K = 2, S
rh = 1.50), with the variation of S
rh (from 0 to 2), K (from 20 to 2), and S
1 (from 0 to 16), respectively. Further, a simple pseudo-analytical model is developed to estimate the pressure drop in EV flow, accounting for the influence of charge-heterogeneity based on the Poiseuille flow in a uniform channel. This model predicts the pressure drop ± 2%–4% within the numerical results. The robustness and simplicity of this model enable the present numerical results for engineering and design aspects of microfluidic applications.
Efficient microfluidic particle separation using inertial pre-focusing and pre-separation structures without sheath flow
Authors: Hou Shuyue , Zhao Ling , Yu Jie , Wang Zhuoyang , Duan Junping , Zhang Binzhen
Published: August 2024

This study introduces an innovative microfluidic particle separation technique that integrates inertial focusing with deterministic lateral displacement (DLD) on a single chip, significantly enhancing the efficiency of particle separation. This new method completes flow rate matching through a designed pre-focusing and pre-separation inertial structure, avoiding the use of sheath flow. The process involves a sequence of channels: a rectangular channel, a contraction-expansion array (CEA), a lateral separation channel, and another rectangular channel. This three-stage inertial method shortens the focusing channel length and reduces the pressure on subsequent separation stages, streamlining the separation process. It has been demonstrated to separate 20 μm particles from a mixture containing both 10 μm and 20 μm particles with remarkable precision. The technique achieves a 100% separation efficiency, ensuring all target particles are correctly isolated, and a 96.1% separation purity, indicating that the isolated particles are almost entirely free from contaminants. By eliminating the need for sheath flow, this method simplifies the apparatus and reduces operational complexity, offering significant advantages over traditional particle separation techniques. The high efficiency and purity levels achieved by this method highlight its potential for a wide range of applications in fields requiring precise particle separation, such as medical diagnostics, environmental monitoring, and industrial processing.
Modeling and dynamic performance of distributed force in high-temperature superconducting pinning magnetic levitation
Authors: Hu Xianhong , Li Hengda , Zhou Xucheng , Zhang Shuonan , Li Haitao , Deng Zigang
Published: August 2024

High-temperature superconducting (HTS) pinning magnetic levitation (maglev) systems are highly promising for future applications in rail transportation. Through the interaction between onboard HTS bulks and the permanent magnet guideway (PMG), this system generates levitation and guidance forces, known as the HTS-PMG relationship. Under practical conditions, this interaction manifests itself as a distributed force. However, past models have only considered concentrated forces. This study aims to design experiments to investigate the HTS-PMG relationship and propose a more realistic discretized lateral-vertical coupling HTS-PMG relationship to accurately reflect torques in dynamic simulations. Based on this, a dynamic model is established to analyze the Sperling index and the five-degree-of-freedom dynamic response of the HTS pinning maglev vehicle system under different HTS-PMG relationship models. The results indicate that the proposed discretized lateral-vertical coupling HTS-PMG relationship accurately characterizes the torque generated by the HTS levitator, influencing lateral, roll, pitch, and yaw motions to some extent. Compared with the concentrated force model, the discrete force model exhibits superior dynamic performance, particularly in terms of lateral dynamics and the lateral Sperling index. This study provides valuable insights into the field of HTS maglev, particularly regarding investigating HTS-PMG relationships and their impact on HTS maglev system dynamic performance.
Entropy-optimized flow of couple stresses in a porous inclined pipe with uniform magnetic field and mixed convention
Authors: Cherala Shiva Shankar , Gajjela Nagaraju , Garvandha Mahesh , Niranjan H
Published: August 2024

The research aims to investigate the entropy-optimized flow of couple stresses in a porous inclined pipe exposed to a transverse constant magnetic field and mixed convection. It focuses on understanding the thermodynamic efficiency and fluid behaviour under convective boundary conditions, contributing to improved designs in engineering applications where such flows are relevant. The aim is to enhance heat transfer efficiency in industrial processes such as chemical reactors, heat exchangers, and geothermal systems, while also improving filtration systems for applications like water purification and oil recovery. By subjecting the flow to a uniform magnetic field and mixed convection, nonlinear governing equations arise due to mixed convection. We linearize these equations using a quasi-linearization approach and solve them using Chebyshev spectral collocation. Our analysis focuses on thermodynamic phenomena like entropy generation and the Bejan number, which have implications for the efficiency and sustainability of industrial processes. We visualize temperature and axial velocity profiles across various parameter ranges to understand the fluid’s behaviour under the influence of magnetic fields and porous materials. As the magnetic parameter increases, there is a decrease in fluid velocity and temperature. However, the opposite tendency is seen for the couple stress viscosity ratio parameter. We also observe irreversibility dominating heat transfer at the pipe wall, while fluid friction irreversibility dominates around the pipe’s centre. This research contributes to advancing our understanding of thermodynamic processes in complex fluid systems and has practical implications for optimizing industrial processes and developing more efficient filtration systems.
Modification of buckwheat husk powder and creation of composite material on its basis
Authors: Cherkashina N I , Kuprieva O V , Pushkarskaya D V , Kashibadze N V , Shrubchenko L F
Published: August 2024

Waste of plant origin is becoming increasingly relevant for use as fillers in polymer matrices to create new composite materials. In this study, a composite material based on biodegradable thermoplastic polylactide (PLA) and buckwheat husks (BHS) was prepared. L-PLA IngeoTM Biopolymer 4043D in pellet form (Nature Works LLC, USA) was chosen as the base for the polymer matrix. BHS in the form of fine powder (harvested in 2023) was used as a plant filler. In order to purify the raw material from dust and pathogenic bacteria, as well as to increase the adhesion ability of the material, BHS was treated with 4% alkaline solution (NaOH). Modification of the filler was carried out using organosilicon resin K-9 (manufacturer Khimprodukt LLC, Lyubertsy, Russia). The filler was added to the material in the ratio of 22%, 32%, 42% by weight of the product. A technology for modification of BHS powder is proposed, which makes it possible to significantly increase the wetting angle from 59.47 ± 1.59° to 95.6 ± 1.35°. The strength properties and water absorption resistance of the developed composites with different weight ratios of PLA/ BHS are investigated. The modification of the filler changes the structure and properties of BHS, as well as contributes to the improvement of strength properties. At the ratio PLA 68 wt% / modified BHS 32 wt% the composite material has the following characteristics: density - 1342 kg m−3, bending strength—21.31 MPa, maximum deformation value—0.22 mm, Vickers hardness at a load of 200 g—20.21, water absorption—1.9%. Research on the utilization of plant components will make it possible to integrate into industry innovative products based on renewable and biodegradable resources that will meet all societal needs and contribute to the preservation of the environment and exhaustible resources.
Multi-particle-based multi-party controllable quantum secure dialogue
Authors: Zhang Xiao-Xue , Zhou Ri-Gui , Xu Wen-Shan
Published: August 2024

Based on the six-particle entangled state, this paper proposes a multi-party controllable quantum secure dialogue protocol, where the dialogue parties only need to perform single operation to efficiently encode secret information and embed the control information into a fixed particle sequence in order, ensuring the orderly transmission of information. Additionally, the protocol introduces a unique honesty detection mechanism, which relies on the classical XOR relationship of three qubits in a GHZ-like state, effectively guaranteeing the credibility of the controllers. The protocol allows two dialogue parties to synchronously obtain secret information with the permission of all controllers, without relying on additional classical channel, greatly enhancing communication efficiency and security. Through rigorous security analysis, it is proven that the protocol can effectively resist various potential attacks from both internal and external sources.
Photons from macroscopic currents
Authors: Dick Rainer
Published: August 2024

Coherent states are a well-established tool of quantum optics to describe electromagnetic waves in terms of photons. However, they do not describe the near-field regime of macroscopic radiation sources. Instead, we generically use classical solutions of Maxwell’s equations to describe radiation in the near-field regime. The classical solutions provide linear relations between currents and emitted electromagnetic fields, whereas evolution of states at the quantum level involves photons. This begs the question how we can describe macroscopic fields from antennas or magnetic coils in terms of elementary photons. The present paper answers this question through the construction of generalized Glauber states for macroscopic radiation emitters.
Global convection-permitting model improves subseasonal forecast of plum rain around Japan
Authors: Gu Jun , Zhao Chun , Xu Mingyue , Feng Jiawang , Li Gudongze , Zhao Yongxuan , Hao Xiaoyu , Chen Junshi , An Hong
Published: August 2024

In 2020 early summer, a historically severe rainy season struck East Asia, causing extensive damage to life and property. Subseasonal forecast of this event challenges the limits of rainy season predictability. Employing the integrated atmospheric model across scales and the Sunway supercomputer, we conducted ensemble one-month forecasts at global 3 km, variable 4–60 km, and global 60 km resolutions. The global convection-permitting forecast accurately captures the rainband, while other forecasts exhibited northward and weaker shifts due to the northward shifts of the atmospheric rivers over Japan, attributed to intensified Western North Pacific Subtropical High (WNPSH). Further, the double-ITCZ-like tropical rainfall pattern in Western Pacific in global convection-permitting forecast contributes to a more accurate WNPSH and rainband. In contrast, other forecasts show a single-ITCZ-like pattern in Western Pacific, leading to a northward-shifted WNPSH and rainband, advocating the importance of accurately representing tropical convections, as they can significantly affect mid-/high-latitude weather and climate.
Strong/weak duality symmetries for Jacobi–Gordon field theory through elliptic functions
Authors: Cartas-Fuentevilla R , Peralta-Martinez K , Zarate-Herrada D A , Calvario-Acocal J L A
Published: August 2024

It is shown that the standard sin/sinh Gordon field theory with the strong/weak duality symmetry of its quantum S-matrix, can be formulated in terms of elliptic functions with their duality symmetries, which will correspond to the classical realization of that quantum symmetry. Specifically we show that the so called self-dual point that divides the strong and the weak coupling regimes, corresponds only to one point of a set of fixed points under the duality transformations for the elliptic functions. Furthermore, the equations of motion can be solved in exact form in terms of the inverse elliptic functions; in spontaneous symmetry breaking scenarios, these solutions show that kink-like solitons can decay to cusp-like solitons.
Projected state ensemble of a generic model of many-body quantum chaos
Authors: Chan Amos , De Luca Andrea
Published: August 2024

The projected ensemble is based on the study of the quantum state of a subsystemAconditioned on projective measurements in its complement. Recent studies have observed that a more refined measure of the thermalization of a chaotic quantum system can be defined on the basis of convergence of the projected ensemble to a quantum state design, i.e. a system thermalizes when it becomes indistinguishable, up to thekth moment, from a Haar ensemble of uniformly distributed pure states. Here we consider a random unitary circuit with the brick-wall geometry and analyze its convergence to the Haar ensemble through the frame potential and its mapping to a statistical mechanical problem. This approach allows us to highlight a geometric interpretation of the frame potential based on the existence of a fluctuating membrane, similar to those appearing in the study of entanglement entropies. At large local Hilbert space dimensionq, we find that all moments converge simultaneously with a time scaling linearly in the size of regionA, a feature previously observed in dual unitary models. However, based on the geometric interpretation, we argue that the scaling at finiteqon the basis of rare membrane fluctuations, finding the logarithmic scaling of design timestk=O(log⁡k). Our results are supported with numerical simulations performed atq = 2.