bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural ordering in anisometric fullerenes
Authors: Gerasimov A. A. , Tugai Yu. V. , Fedorchenko D. V.
Published: January 2025

A molecular model of spatial and orientational ordering is proposed for the one-dimensional, translationally ordered, anisotropic (R2 ⊗ Z1 ⋀ D∞h) condensed phase of Van der Waals molecules. The application of the model to molecular systems such as plastic and liquid crystals is considered for anisotropic fullerites and smectic-A mesophases. It is shown that steady-state translational ordering removes the degeneracy in the direction of the preferred orientation axis of the molecules and leads to the emergence of crossed terms in the pseudopotential, which induce orientational ordering. The temperature dependence of order parameters is calculated numerically, and phase transition temperatures are obtained as functions of molecular parameters. It is shown that the obtained phase diagrams are in a qualitative agreement with the available results for liquid-crystal structures. The structural transition temperature for parameters corresponding to a C70 molecule is estimated as TPC–I ≈50 K. This value suggests that the condensed phase of C70 is structurally disordered over practically in the entire range of its existence.
The dynamics and low-temperature heat capacity of a monatomic linear chain with a two-parametric substitutional impurity
Authors: Syrkin E. S. , Feodos’ev S. B.
Published: January 2025

Exact analytic expressions for spectral densities, the spectral shift function, and the total change in the phonon spectrum as well as the low-temperature heat capacity of a one-dimensional crystal containing a two-parametric substitutional impurity are obtained and analyzed as functions of the defect parameters (changes in the mass and in force constants). Calculations are made by using the chain fraction apparatus. Special attention is paid to the results that cannot be obtained in the model of the defect taking into account only the change in mass. These results include, for example, the possibility of formation of quasilocalized states in the intermediate region of continuous spectrum by a light weakly coupled impurity. In addition, it is shown that two local vibrations are formed for any (however large) mass of an impurity atom if the force of coupling of the impurity with its nearest neighbors is two or more times stronger than the force of coupling between atoms in the matrix lattice.
Temperature singularities of IR reflection spectra of N2O cryocrystals
Authors: Drobyshev A. S. , Garipoglyi D. N. , Maksimov S. L. , Samyshkin E. A.
Published: January 2025

Measurements of the reflection spectra in the IR region and an analysis of the spectral singularities near the intramolecular resonance frequency lines reveal the existence of a phase transition in a nitrogen oxide film cryodeposited on a metallic mirror.
Anomalous dephasing of optical transitions of a Pr3+ ion in Y2SiO5 crystal
Authors: Malyukin Yu. V. , Pogrebnyak N. L. , Seminozhenko V. P.
Published: January 2025

The temperature drops in the photon echo intensity have been studied for the first time in the low-symmetry impurity crystal Y2SiO5:Pr3+ in the temperature range 4.2–20 K on the resonance transitions 3P0–3H4 and 1D2–3H4 of the Pr3+ ion. It is shown that the obtained results can be interpreted by using the familiar mechanisms of dephasing of optical transitions in impurity ions.
On the theory of fermion pairing in the problem of superconductivity and superfluidity
Authors: Akhiezer A. I. , Peletminskii S. V. , Yatsenko A. A.
Published: January 2025

Fermion pairing in the problem of superconductivity and superfluidity, caused by direct interaction between particles, is studied. A self-consistent equation is obtained for the transition temperature in a system of fermions of different species. It is shown that the results in this case may differ qualitatively from those obtained from the BCS theory. Pairing between electrons and positrons caused by screened Coulomb interaction is investigated. The temperature dependence is found to be asymptotic both for high and low densities of the electron-positron plasma.
Macroscopic dynamics of the interface between crystals and total resonant transmission of phonons
Authors: Kosevich Yu. A. , Syrkin E. S.
Published: January 2025

A macroscopic description is proposed of the dynamical properties of the interface between two media in the presence on it of a planar defect with an internal dynamical degree of freedom. In order to describe the interaction of a two-dimensional defect layer with a bulk elastic continuum, a new dynamical variable on the interface displacement us is introduced. The coupled long-wavelength equations of motion of the defect layer and the elastic substrate are obtained as a set of nontraditional boundary conditions for the bulk equations of the theory of elasticity. The interaction of the bulk elastic waves with the two-dimensional defect is considered. The phenomenon of the total resonance transmission of acoustic waves (phonons) across the interface of two media in the case of their strong acoustic mismatch is predicted to occur due to the weakly-bonded (physisorbed) impurity monolayer. The connection of the phenomenon of the total transmission and nonreflection with resonant interaction of the incident wave and the gap leaky interface wave is clarified. The possible contribution of the phenomenon to the Kapitza thermal boundary resistance is discussed.
Continuous-cycle dilution refrigerator with adsorption evacuation
Authors: Maidanov V. A. , Mikhin N. P. , Omelaenko N. F. , Rudavskii E. Ya. , Rybalko A. S. , Chagovets V. K. , Mikheev V. A. , Mohandas P. , Cawn B. P. , Sounders J.
Published: January 2025

The construction of the basic elements and working characteristics of two versions of a continuous-cycle dilution refrigerator with adsorption evacuation, intended for physical investigations at ultralow temperatures, are described. In comparison with the traditional dilution refrigerators, the versions described here are more compact, economical, have a good vibration insulation, and can also easily be used for organizing a one-cycle dilution regime. The minimum temperature attained in the refrigerator with a single continuous-flow heat-exchanger is 18 mK in the continuous cycle operation and 5–8 mK in the single-cycle regime. The minimum temperature in the continuous-cycle dilution refrigerator can be decreased to 8 mK by introducing discrete heat-exchangers.
Investigation of bolometric response of a superconducting film to external IR radiation in non-Josephson generation regime
Authors: Dikin D. A. , Dmitriev V. M. , Churilov G. E.
Published: January 2025

Studies of the behavior of superconducting thin films in resistive current state revealed that they are not only sources of Josephson generation, but also non-Josephson generation (NJG) at much lower frequencies (106–108 Hz). A significant feature of NJG is that the generation frequency fg is very sensitive to the variation of external factors like direct current, temperature, and electromagnetic radiation. The high sensitivity of the generation frequency to external agencies can be used for creating a new class of detecting elements. In the present paper, we study the response of a superconducting film to external infrared (IR) radiation in non-Josephson generation regime and estimate its bolometric characteristics.
Splitting of the ground multiplet of Nd3+ ion in the crystal electric field of NdAI and Nd3AI11 compounds
Authors: Vasil’kevish A. A. , Ivanitskii P. G. , Slisenko V. I. , Krotenko V. T. , Maistrenko A. N. , Markiv V. Ya.
Published: January 2025

The energy structure of the ground multiplet 4I9/2 of the Nd3+ ion in the crystal electric field (CEF) of the compounds NdAI and Nd3AI11 is studied by the method of inelastic scattering of slow neutrons. The obtained parameters of the CEF Hamiltonian are used for calculating the Schottky heat capacity CSch and the magnetic susceptibility χ0 of the NdAI compound. The results of measurements of CSch for NdAI are also presented. The calculated and available experimental results of measurements of CSch and χ0 for NdAI are compared.
Low-frequency internal friction anomaly in crystalline methane
Authors: Leont’eva A. V. , Marinin G. A. , Prokhorov A. Yu. , Sukharevskii B. Ya.
Published: January 2025

The temperature dependence of the low-frequency internal friction (LFIF) and the dynamic shear modulus f2 in polycrystalline methane samples is studied over the temperature interval 5–85 K. A sharp LFIF peak and the variation of shear modulus are observed at temperatures of 60–70 K. It is suggested that these anomalies are due to a transition of methane molecules from retarded rotation at T<60 K to a more unhindered motion at T>60–70 K. It is found that an increase in the N2 impurity shifts this transition to higher temperatures. The internal friction peak and the increase in the LFIF background around 20.48 K are attributed to the onset and completion of the β-α phase transition caused by orientational ordering of methane molecules. It is assumed that an increase in the internal friction background below 20 K and the LFIF peak in the temperature interval 10–15 K are due to quantum relaxation processes associated with spin conversion in CH4. A qualitative explanation based on the variation of the dynamic behavior of CH4 molecules is offered for LFIF anomalies.
Plasticity of Al-Li alloys in the temperature range 0.5-300 K: Low-temperature anomalies, deformation instability and the effect of superconducting transition
Authors: Isaev N. V. , Pustovalov V. V. , Fomenko V. S. , Shumilin S. È.
Published: January 2025

Plastic deformation of binary alloys Al+3.8, 7.0, or 10.4 at. % Li is studied under conditions of extension at a constant rate at temperatures down to 0.5 K. The temperature dependences of the plasticity parameters are studied, low-temperature singularities of these dependences are established, and their origin is discussed. In the temperature interval 4.2–0.5 K, the effect of the degree of deformation, temperature, and superconducting transition on the jumpwise deformation of alloys is studied. A qualitative comparison is made between the experimental data and the prevailing theories of thermomechanical deformation instability.
Temperature dependence of thermo-emf and isothermal resistance of HTS crystals in the vicinity of superconducting transition
Authors: Tszyan Yu. N. , Shevchenko O. G.
Published: January 2025

The thermo-emf and conductivity of the crystals of Bi2Sr2CaCu2Ox and HoBa2Cu3Ox are studied near the superconducting transition temperature. Below the mean-field critical temperature, the temperature dependence of the thermo-emf differs sharply from that expected from the theory of fluctuations of superconducting Cooper pairs. The temperature variation of thermo-emf is also observed in the case when the resistance of the crystal is already equal to zero. This peculiarity in the behavior of thermo-emf is associated with the fluctuational contribution of pairs of 2D-magnetic vortices which are sensitive to non-isothermal conditions under which thermoelectric measurements were made.
Two-magnon scattering of light in the low-temperature phase of the quasi-two-dimensional antiferromagnet NH3(CH2)2NH3MnCI4
Authors: Eremenko V. V. , Kurnosov V. S. , Fomin V. I.
Published: January 2025

The mechanisms of formation of two-magnon scattering spectra in a quasi-two-dimensional antiferromagnetic crystal NH3(CH2)2NH3MnCl4 are considered on the basis of the available experimental data on Raman scattering and absorption of light. The density of magnon states is calculated, and polarization selection rules for two-magnon spectra are formulated on the basis of four-sublattice model of antiferromagnetic crystal layers.
Spontaneous magnetostriction effects in α- and β-phases of oxygen
Authors: Baryl’nik A. S. , Prokhvatilov A. I.
Published: January 2025

X-ray diffraction studies of polycrystalline oxygen reveal a strong spontaneous magnetostriction in the rhombohedral phase, leading to considerable nonuniform deformational distortions of the lattice and a partial amorphization of crystals in the vicinity of the temperature of transition to the antiferromagnetic phase. The obtained results point towards the formation of quasi-two-dimensional regions of short-range magnetic order in the basal planes of β-oxygen. Experimental information is obtained about the primacy of low-temperature transformation and the possibility of realizing an intermediate modulated magnetic structure in its vicinity.
Electron-phonon interaction in low-temperature resistivity of amorphous transition metals
Authors: Shvets V. T.
Published: January 2025

For the first time, an expression that is valid over the entire temperature interval of existence of amorphous and liquid phases is obtained for the electrical resistance of disordered, nonmagnetic transition metals with relatively low resistivity. Hybridization of the s- and d-electron states and electron-phonon interaction (which determines the temperature dependence of the electrical resistance) are chosen as the basic mechanisms determining the scattering of conduction electrons. A new structural function of the metal is introduced for the first time and computed in the harmonic approximation by using Debye’s model. The temperature dependence of the electrical resistance of amorphous transition metals in the low-temperature range is studied in detail. The quadratic dependence of the electrical resistance on the temperature, which is well-known from the experiments, is observed.
Alfven waves in gallium
Authors: Bezuglyi E. V. , Burma N. G. , Deineka E. Yu. , Stepanenko A. M. , Fil’ V. D.
Published: January 2025

Alfvén-type magnetoplasma waves excited in high-purity gallium at a frequency 50–150 MHz in a magnetic field 10–35 kOe have been experimentally observed and investigated. The measured values of the Alfvén velocity are in good agreement with the results of its numerical calculations on the basis of Reed’s model for the electron spectrum of Ga with a fitting value of the averaged Fermi velocity close to the one used earlier [E. V. Bezuglyi et al., Fiz. Nizk. Temp. 19, 300 (1993); Sov. J. Low Temp. Phys. 19, 211 (1993)] for calculating the spectrum of a fast magnetoacoustic wave and estimating the Fermi liquid interaction parameter in gallium. The temperature dependence of the Alfvén wave velocity can be used to estimate the frequencies of electron-electron and electron-phonon relaxation in gallium, which are found to be in good agreement with the results of other measurements.
Dimensional dependence of the structure of nitrogen and argon clusters formed in supersonic jets
Authors: Kovalenko S. I. , Solnyshkin D. D. , Verkhovtseva E. T. , Eremenko V. V.
Published: January 2025

Electron diffraction studies have been carried out in clusters formed in supersonic jets of Ar and N2. It is shown that a dimensional phase transition of the crystal structure into a quasicrystalline (icosahedral) structure takes place in clusters containing less than 800 particles. The phase transition takes place in clusters of argon as well as nitrogen in which the interaction between particles is more complex than in inert gases. The effect of the mean size of Ar clusters on the mean-square amplitude ⟨u2⟩1/2 is studied, and the dependence of this quantity on the average number of atoms in a cluster is analyzed. Diagnostic characteristics of clusterized beams of investigated gases are obtained, and a good correlation with the theory of corresponding ” jets is demonstrated.
Observation of non-ohmic component of spontaneous conductivity fluctuations in YBa2Cu3O7–x thin films
Authors: Brodyanskii A. P. , Dmitrenko I. M. , Garbuz A. S. , Efremenko V. G. , Klimovskii Yu. A. , Fomin A. V. , Shustakova G. V. , Erenburg A. I.
Published: January 2025

Resistive and noise properties of thin single-crystal YBa2Cu3O7–x films with the c axis being parallel to the substrate plane have been studied. In the normal state as well as in the region of the superconducting transition we observed variations of the resistance fluctuation spectral density with current, which is direct evidence of structure elements with nonlinear current-voltage relationships present in high-Tc materials. On the basis of a comparison of data for c‖ and c⊥ films, certain inferences are made about the microscopic origin of the structure elements, responsible for the current nonlinearities in the noise properties of HTSC.
Spin-orientational phase transitions and magnetic structure of low-dimensional noncollinear Ising magnet KDy(MoO4)2
Authors: Khatsko A. S. , Chernyi A. S. , Kaplienko A. I.
Published: January 2025

The temperature dependence of the principal values of the magnetic susceptibility of KDy(MoO4)2 single crystals in the temperature interval 0.5−300 K and the field dependences of magnetization in magnetic fields up to 14 kOe in the temperature range 0.5−4.2 K are studied. Combined application of the data of crystal structure, EPR magnetization and magnetic susceptibility investigations has made it possible to explain the observed magnetic properties of KDy(MoO4)2 and to determine the type of its magnetic structure.
On hysteretic behavior of the heat capacity C
P of HTS cuprates in the normal state
Authors: Saiko A. P. , Gusakov V. E.
Published: January 2025

The contribution of anharmonically unstable oxygen sublattice to the specific heat of HTS cuprates at constant pressure is calculated. The experimentally established hysteretic behavior and singularities (peaks) on cooling and heating curves for CP(T) in the normal state are explained.
Theoretical Calculations of HfSe3 Band Characteristics and Its Applications in Pulse Fiber Lasers
Authors: Feng Weiwei , Chen Ligang
Published: January 2025

Transition metal trichalcogenides (TMTs) are known for their two-dimensional (2D) characteristics and the presence of quasi one-dimensional chains. These materials are less vulnerable to edge defects, which makes them suitable for optical and electronic devices with low-dimensional structures. This study demonstrates the application of HfSe3 nanomaterial as an emerging ultrafast photonic device capable of producing mode-locked and Q-switched pulses in fiber lasers. The nonlinear optical absorption properties of a HfSe3-based saturable absorber (SA) were analyzed, revealing a modulation depth of 7% and nonsaturable loss of 35%, respectively. In addition, first principles-based theoretical calculations were performed to explore the optoelectronic properties of bulk HfSe3. The integration of the HfSe3-based SA into an Er-doped fiber laser cavity enabled both Q-switched and mode-locked pulse operations. For the mode-locked operation, the pulse duration was 560 fs, accompanied by a signal-to-noise ratio (SNR) of 71.43 dB. In the Q-switched regime, the narrowest pulse width recorded was 757.1 ns with an SNR of 75.45 dB. This study indicates that nanodevices based on 2D TMTs hold promise for efficient ultrafast photonic applications and can be extensively employed in nonlinear optical technologies.
Mechanical sensors based on surface plasmon polaritions of strained graphene
Authors: Liu Liang , Zhou Shuai , Liu Kaipeng , Dai Shiwei , Ge Lixin
Published: January 2025

Graphene sheets support surface plasmon polaritons (SPPs) in the terahertz and infrared regimes, resulting from the collective oscillation of Dirac electrons with excited photons. The SPPs in graphene under external strains exhibit anisotropic properties, varying with the magnitude and direction of mechanical deformation. In this study, we propose an mechanical sensor based on the strain-dependent absorption spectrum of infrared light. The setup consists of a monolayer strained graphene sheet suspended over a grating silver substrate. Under a normal incidence, a strong absorption for transverse magnetic polarization is observed, attributed to the excitation of graphene SPPs. Additionally, the resonances of the absorption spectra can be significantly modulated by the magnitude and direction of the applied strains. Finally, the sensitivity and quality of proposed sensors are evaluated under different configurations. For a moderate condition, the figure of merit with respect to the strain deformation can be larger than 20, and such high values are attributed to the intrinsic low loss of graphene sheet. This work paves the way for sensing applications based on the SPPs of strained graphene.
In-situ disinfection by flexible surface dielectric barrier discharge plasma film: discharge modes and mechanisms
Authors: Zhang Liyang , Zhang Xu , Tie Jinfeng , Luo Haiyun , Guo Yuntao , Zhou Qun
Published: January 2025

In this work, a surface-dielectric-barrier-discharge (SDBD) based flexible plasma film (FPF) was established and tested for in-situ surface disinfection. The discharge product mode (i.e. O3 mode and NO
x
mode) was controlled by the applied voltage and verified by in situ gas product quantification. For in situ disinfection, the NO
x
mode shows significantly higher bactericidal efficiency than the O3 mode, and the FPF achieves ∼3.5 logs and >6 logs of bacterial reduction with 3 and 5 min of plasma exposure in the NO
x
mode, respectively. The underlying mechanism is investigated. In the O3 mode, the heating effect of the plasma plays either a negligible or moderate role in bacterial inactivation, depending on the applied voltage. In the NO
x
mode, both high temperature and long-lived species can play a role, while it is speculated that short-lived species are primarily responsible for the high-order bactericidal rate (>3 logs), with atomic oxygen likely playing an important role. As revealed by scanning electron microscopy and Fourier-transform infrared (FT-IR) spectroscopy, the NO
x
mode can lead to more pronounced bacterial etching and nitrification compared to the O3 mode, accounting for its superior disinfection performance. By examining the time-dependent FT-IR infrared spectra of treated bacteria, it is found that nitrification is the dominant spectral variation, and the ratio of infrared bands at 1354 and 1654 cm−1 can serve as a positive indicator of disinfection efficiency. This study can provide deeper insights into the discharge mode, disinfection performance, and bactericidal mechanisms of the SDBD-based FPF, offering guidance for the control, evaluation, and future applications of this technology.
Diffusion transformer model with compact prior for low-dose PET reconstruction
Authors: Huang Bin , Liu Xubiao , Fang Lei , Liu Qiegen , Li Bingxuan
Published: January 2025

Objective. Positron emission tomography (PET) is an advanced medical imaging technique that plays a crucial role in non-invasive clinical diagnosis. However, while reducing radiation exposure through low-dose PET scans is beneficial for patient safety, it often results in insufficient statistical data. This scarcity of data poses significant challenges for accurately reconstructing high-quality images, which are essential for reliable diagnostic outcomes. Approach. In this research, we propose a diffusion transformer model (DTM) guided by joint compact prior to enhance the reconstruction quality of low-dose PET imaging. In light of current research findings, we present a pioneering PET reconstruction model that integrates diffusion and transformer models for joint optimization. This model combines the powerful distribution mapping abilities of diffusion model with the capacity of transformers to capture long-range dependencies, offering significant advantages for low-dose PET reconstruction. Additionally, the incorporation of the lesion refining block and alternating direction method of multipliers enhance the recovery capability of lesion regions and preserves detail information, solving blurring problems in lesion areas and texture details of most deep learning frameworks. Main results. Experimental results validate the effectiveness of DTM in reconstructing low-dose PET image quality. DTM achieves state-of-the-art performance across various metrics, including PSNR, SSIM, NRMSE, CR, and COV, demonstrating its ability to reduce noise while preserving critical clinical details such as lesion structure and texture. Compared with baseline methods, DTM delivers best results in denoising and lesion preservation across various low-dose levels, including 10%, 25%, 50%, and even ultra-low-dose level such as 1%. DTM shows robust generalization performance on phantom and patient datasets, highlighting its adaptability to varying imaging conditions. Significance. This approach reduces radiation exposure while ensuring reliable imaging for early disease detection and clinical decision-making, offering a promising tool for both clinical and research applications.
Probing the impact of oxygen negative ions on the self-organized pattern in 1 atm DC glow with liquid anode
Authors: Yang Zimu , Yatom Shurik , Foster John E
Published: January 2025

In an atmospheric DC glow discharge with liquid anode, the plasma attachment under certain conditions self-organize into coherent patterns at the anode. Optical emission spectroscopy revealed that attachment emission consists primarily of the second positive system of nitrogen N2(C-B) whose excitation energy is low and sensitive to the change of electron energy distribution. Besides the electrons, negative ions can also accumulate in the anode sheath and affect the local space charge. It has been conjectured that these negative ions play a role in pattern formation at the anode surface. In this work, the role of oxygen negative ions was explored. It was found that the establishment of anode patterns requires at least a 7 % volume fraction of oxygen in the ambient gas. Results showed that at least in this work, O2- is the dominant negative ion species and has a density ~10^13 cm^-3. While the presence of oxygen appears crucial to pattern formation, this study indicated that the mere presence of the negative ions itself was not sufficient for pattern formation, suggesting a more complex mechanism involving electronegative species must be present. In fact, it was found that even when as many as 67 % of negative ions in the plasma were detached, no obvious geometry changes were observed in the self-organized pattern.
Sculpturing sound fields with the real-space structural topology of acoustic cavities
Authors: Tong Qing , Wang Shubo
Published: January 2025

Artificial structures have been widely employed to manipulate sound fields to realize intriguing acoustic phenomena and functionalities. The development of this field requires a thorough understanding of how sound fields depend on the various properties of artificial structures. Although the effects of the material and geometry of artificial structures are known well, the effects of the real-space structural topology on sound field properties remain unclear. To tackle this problem, we present a detailed study of the sound fields inside acoustic cavities with different Euler characteristics and demonstrate that the real-space topology can give rise to topological configurations of the velocity and pressure fields. Specifically, we find that the acoustic cavities can induce topological singularities in the velocity polarization and isopressure line fields. The total topological index of the surface singularities is always equal to the cavities’ Euler characteristic. The mechanism is rooted in the Poincaré–Hopf theorem and is irrelevant to the specific material, geometric details, or excitations. The isopressure line singularities lead to acoustic hotspots and quiet zones. The velocity polarization singularities give rise to nontrivial polarization Möbius strips and skyrmion textures. These topological configurations can be directly manipulated by controlling the cavities’ Euler characteristics. Our work uncovers the fundamental relationship between the topological properties of sound fields and the topological properties of structures. The results enable sound sculpturing with structural topology, and the acoustic cavities can serve as a platform for characterizing the topological properties of sound fields in three-dimensional space.
Tunable graphene based terahertz sensor for biochemical sensing with ML-driven refractive index prediction
Authors: Challa Ram Grandhi , Venkata Subbarao M , Maurya Naveen Kumar , Yuvaraj S
Published: January 2025

This paper presents the design and analysis of a tunable terahertz sensor at 2.65 THz for biochemical sensing. The Bandpass characteristics in the frequency response of the sensor are achieved by coupling a rectangular split ring resonator to the transmission line. Graphene layer is deployed in the design to facilitate the propagation of surface plasmons and to incorporate the tunability in thefrequency response. The simulation results reveal that the designed sensor is capable of achieving the desired frequency response. By varying the applied voltage across the graphene the designed sensor can be tuned over a range of 80 GHz. The proposed design can be employed as a highly sensitive biosensor for detection of samples like ethanol, water, sodium chloride, glycerine and others.The designed sensor offers a maximal sensitivity of 200 GHz per refractive index unit change. Further, machine learning based regression models are considered for predicting the refractive index of the sample from the sensor response. The prediction is based on the frequency response of a sensor, which serves as a reliable indicator of changes in the analyte’s refractive index. Results indicatethat the Gaussian process regression model outperforms the other models with 0.0099 root mean square error.
Investigation of triple vertically stacked nanosheet FET with geometric variability at advanced technology node: DC, analog and RF performance benchmarking
Authors: Dewangan Ram Krishna , Singh Vinay Kumar , Khan Mohammad Rafique
Published: January 2025

This paper presents an in-depth analysis of the digital, analog, and radio frequency (RF) performance metrics of three-dimensional gate-all-around (GAA) triple nanosheet field-effect transistor (NSFET) designed for the 5 nm technology node. By optimizing the key physical dimensions of the NSFET specifically, a nanosheet width of 20 nm, thickness of 5 nm, and gate length of 12 nm, significant improvements in device performance were achieved. The optimized NSFET demonstrated a remarkable Ion/Ioff ratio of 2.99 × 106, a low subthreshold swing of 65.63 mV /dec, and minimal drain-induced barrier lowering (DIBL) of 21.94 mV/V. Additionally, the device exhibited enhanced transconductance (gm = 3.2 × 10−4 S), contributing to a high intrinsic gain (Avo = 47 dB). In terms of RF performance, the NSFET achieved a cut-off frequency (fT) of 394 GHz and a maximum oscillation frequency (fmax) of 491 GHz, showcasing its potential for high-frequency applications. These results highlight the superior performance of NSFETs over FinFETs, making them a promising candidate for digital, analog, and RF circuit designs in advanced sub-5 nm technology nodes. The combination of excellent electrical characteristics and high-frequency performance positions NSFETs as a leading solution for next-generation integrated circuits.
Design of a metasurface loaded with RF varactor and PIN diode integration dual-band reconfigurable antenna for bluetooth, Wi-Fi, WLAN and wireless 5G applications
Authors: Pande Suyog , Patil Dipak , Kumar Akhilesh , Tyavlovsky Andrey , Muthanna Ammar
Published: January 2025

This article presents a compact dual-band reconfigurable antenna design utilizing a metasurface integrated with an RF varactor and PIN diode for Bluetooth, Wi-Fi, WLAN, and 5G wireless applications. The results of the study show that using the metasurface reflector (MSR) structure gives a much higher gain than using a decagon antenna without a metasurface reflector. This antenna is designed and fabricated on FR4 epoxy substrate materials with a dielectric constant of 4.4 and the thickness of the substrate is 1.6 mm. The metasurface reflector (MSR) loaded antenna has a total electrical dimension of 0.51λ0 × 0.49λ0 × 0.013λ0, where λ0 represents the resonating wavelength at a 2.6 GHz center frequency. In the proposed work, the slotted decagon patch antenna consists of a complementary split-ring resonator constructed on its ground plane. Moreover, for the frequency reconfiguration, a PIN diode switch and an additional varactor diode switch are used for tuning the frequency band. Furthermore, without affecting the radiator structure, the varactor diode is placed on the upper side of the patch and the PIN diode switch is integrated into the ground plane. The proposed antenna has reconfigurable and tunable operating frequencies of 2.6 GHz and 3.4 GHz. The operational frequency of the band is switched between 2.6 GHz to 3.4 GHz. The switching operation of the dual configuration of 2.6 GHz with the PIN diode ON and 3.4 GHz with the PIN diode OFF. However, simultaneously applying a reverse bias voltage to the varactor diode from 0–10 V shifts its resonance frequency from 2640–2510 MHz and frequency tuning is done in respective bands. The proposed antenna achieved a peak gain of 7.5 dBi, and a radiation efficiency range of 72%–82% in the overall operating bands of interest. The proposed work is used for Bluetooth, Wi-Fi, WLAN, and wireless 5G applications. Performance verification is done by fabricating prototypes and verifying their performance using simulation and testing results.
Neutrino observables in gauged $U(1)_{L_\alpha - L_\beta}$ models with two Higgs doublet and one singlet scalars
Authors: Lou Yuanchao , Nomura Takaaki
Published: January 2025

We discuss neutrino sector in models with two Higgs doublet and one singlet scalar fields under local $U(1)_{L_\alpha- L_\beta}$ symmetry.A neutrino mass matrix is formulated for these models where the matrix is generated via type-I seesaw mechanism introducing right-handed neutrinos.The neutrino mass matrix has more degrees of freedom compared to minimal scenarios which have only one new scalar field, but its structure is still restricted by the symmetry.Then it is find that sum of neutrino mass can be lower than minimal scenarios and it is easier to satisfy observed constraints.In addition, we can fit neutrino data for $U(1)_{L_e - L_{\mu(\tau)}}$ cases which are disfavored in minimal models. Furthermore, some correlations among sum of neutrino mass and CP violating phases are still found although we have more free parameters. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Effects of repetitive thermal loads on microstructure and mechanical properties of potassium-doped tungsten alloy as plasma facing material
Authors: Wang Hui , Xie Zhuo-Ming , Zhu Da-Huan , Yu Mu-Lan , Fu Yin-Juan , Liu Rui , Wang Xian-Ping , Fang Qian-Feng , Liu Chang-Song , Wu Xue-Bang
Published: January 2025

Plasma-facing materials (PFMs) in fusion reactors are inevitably subjected to severe thermal shocks, making the performance of tungsten (W)-based PFMs under repetitive high thermal loads critical for the long-term stable operation of fusion reactors. Potassium-doped W (W–K) alloys present a promising alternative for PFMs due to their superior thermal and mechanical properties. However, unlike conventional second-phase particles, the K bubbles within W alloys do not form distinct phase interfaces with the W matrix, leaving their behavior poorly understood under transient thermal loads. This study investigates the effects of cyclic thermal loads on the evolution of K bubbles and mechanical properties of W–K alloys. Thermal load tests were conducted with a single-pulse duration of 1 s at absorbed power densities of 10, 13, 15 and 20 MW m−2 for 50 cycles at room temperature. Tensile test results indicate an unexpected increase in ductility in the W–K alloy while maintaining high strength after exposure to thermal loads at 10 and 13 MW m−2. Microstructural analyses reveal that K-tubes with large aspect ratios rupture due to Rayleigh instability, leading to the formation of well-dispersed, nano-sized polyhedral K bubbles. These fine K bubbles, with abundant dislocations at their interfaces, serve as dislocation sources, enhancing ductility. The present work offers a physical depiction of K bubble evolution in W–K alloys under thermal fatigue conditions relevant to fusion environments, suggesting a strategy for optimizing their mechanical properties by promoting the formation of nano-sized, interface-dislocation-decorated K bubbles.
Optical Nonreciprocity of Au Nanoparticles
Authors: Sun Shaoling , Lou Chaogang
Published: January 2025

Developing optical devices that allow light to propagate in only one direction, known as non-reciprocal propagation, is important for various applications. A method for optical nonreciprocity is proposed by utilizing the localized surface plasmons of random metallic nanoparticle arrays. Compared to other methods for generating optical nonreciprocity, this method exhibits the optical nonreciprocity in a wide band and is easy to be fabricated.
Investigating the Role of Rare-earth Gd Doping in Zinc Oxide for Potential in Spintronics
Authors: Tawil S N M , Raship N A , Nurulfadzilah A R
Published: January 2025

Thin films of Gd-doped ZnO with high transparency were prepared using sol-gel derived precursor. In this paper, Gd-doped ZnO films were formed on glass substrates at different Gd concentrations ranging from 0 to 10 at.%. XRD analysis revealed that higher Gd concentration led to an increase in the FWHM value and decrease in crystallinity. Nevertheless, there were no new peaks found that were linked to the development of secondary phases. FESEM revealed changes in surface morphology upon increase in Gd concentration. The MFM measurements observed magnetic signal for thin films doped with Gd, showed by bright-dark contrast of the MFM images. The magnetic properties by VSM discovered that Gd doping generated magnetic behavior with good hysteresis curve and high saturation magnetization observed at 8 at.% of Gd. Overall results indicate that Gd concentration gives significant changes to the properties of the thin films, with 8 at.% of Gd as optimal thin film potential for spintronics applications.
Effects of multiple quantum well width on InGaAs/InP laser diode
Authors: Zhou Wenli , Lai Hanyi
Published: January 2025

InGaAs-based laser diodes (LDs) are widely used for decades due to their high resistance to heat, high speeds, high output power and low threshold current. The width of multiple quantum well (MQW) is one of the most essential parameters that is directly linked to the characteristic of LDs. However, tuning the MQW width is a cumbersome task for fabrications. Therefore, this paper examines the effect of multiple quantum well width on the performance of InGaAs/InP-based laser diodes (LDs). The optical and electrical characteristics of laser diodes with varying quantum well widths are numerically analysed using Lumerical software. The results indicate that a 10-nm-wide MQW LD exhibits optimal performance within the 9 to 11 nm range, with a six-period quantum well structure, achieving the lowest threshold current. Additionally, the peak emission frequency is identified and discussed. The simulation results will assist engineers make the most appropriate decision when determining the MQW width for InGaAs-based LDs.
3D tracking method based on digital holographic microscopy
Authors: Li Xinyu , Li Chenxi , Yang Zhonghong , Zhao Dongjie , Zhai Jia , Chen Wenliang , Liu Rong
Published: January 2025

3D tracking is an important technique for investigating biophysical processes, which provides abundant information for cell identification and characterization. In this paper, we present an effective and practical 3D tracking approach based on digital holographic microscopy (DHM) with auto-focusing reconstruction and a dynamical light-scattering filtering algorithm. An off-axis DHM system was established to capture the holograms of flowing samples. Utilizing reliable auto-focusing, the flowing samples were reconstructed. To improve the resolution and contrast, the principal component analysis filtering method was applied to eliminate the background, speckle noise and interference fringes. Combining the 2D positions of the flowing samples in the focal plane with the depth positions obtained from auto-focusing, the 3D trajectory and velocity of the flowing samples were obtained. The results demonstrated that the method could achieve simultaneous measurement of size and velocity of objects while satisfying signal-to-noise ratio and resolution, providing a foundation for high-throughput cell classification and multi-parameter characterization.
Electroencephalogram features reflect effort corresponding to graded finger extension: implications for hemiparetic stroke
Authors: Haddix Chase , Bates Madison , Garcia-Pava Sarah , Salmon Powell Elizabeth , Sawaki Lumy , Sunderam Sridhar
Published: January 2025

Brain-computer interfaces (BCIs) offer disabled individuals the means to interact with devices by decoding the electroencephalogram (EEG). However, decoding intent in fine motor tasks can be challenging, especially in stroke survivors with cortical lesions. Here, we attempt to decode graded finger extension from the EEG in stroke patients with left-hand paresis and healthy controls. Participants extended their fingers to one of four levels: low, medium, high, or ‘no-go’ (none), while hand, muscle (electromyography: EMG), and brain (EEG) activity were monitored. Event-related desynchronization (ERD) was measured as the change in 8–30 Hz EEG power during movement. Classifiers were trained on EEG features, EMG power, or both (EEG+EMG) to decode finger extension, and accuracy assessed via four-fold cross-validation for each hand of each participant. Mean accuracy exceeded chance (25%) for controls (n = 11) at 62% for EMG, 60% for EEG, and 71% for EEG+EMG on the left hand; and 67%, 60%, and 74%, respectively, on the right hand. Accuracies were similar on the unimpaired right hand for the stroke group (n = 3): 61%, 68%, and 78%, respectively. But on the paretic left hand, EMG only discriminated no-go from movement above chance (41%); in contrast, EEG gave 65% accuracy (68% for EEG+EMG), comparable to the non-paretic hand. The median ERD was significant (p < 0.01) over the cortical hand area in both groups and increased with each level of finger extension. But while the ERD favored the hemisphere contralateral to the active hand as expected, it was ipsilateral for the left hand of stroke due to the lesion in the right hemisphere, which may explain its discriminative ability. Hence, the ERD captures effort in finger extension regardless of success or failure at the task; and harnessing residual EMG improves the correlation. This marker could be leveraged in rehabilitative protocols that focus on fine motor control.
Predicting carbon peak at the provincial level using deep learning
Authors: Tang Xiaoyan , Fang Kunsheng
Published: January 2025

Assessing carbon peak status is crucial in designing mitigation strategies for provinces to mitigate CO2 emissions while maintaining economic development. This study proposes a comprehensive research framework to evaluate carbon peak status at the provincial level. The framework involves identifying the critical emission sources and their primary contribution sectors using the LASSO regression method, predicting the CO2 emissions of critical sources using recurrent neural networks, and exploring mitigation schemes using scenario analysis. This study uses Guizhou Province as an example and analyzes the CO2 emissions of 17 energy consumption types and one production process in 47 socio-economic sectors and discovers that: ① Between 1997 and 2005, the most critical sources of CO2 emissions were the consumption of Raw Coal; ② Between 2006 and 2021, the critical sources of emissions were the consumption of Raw Coal, Other Washed Coal (OWC), and Diesel Oil, and one industry process (Cement Production Process, CPP); ③ Between 2006 and 2021, the primary contribution sector for Raw Coal and OWC emissions is the Production and Supply of Electric Power, Steam, and Hot Water (PSEPSHW) sector. The main contributors to Diesel Oil emissions are the Transportation, Storage, Post and Telecommunication Services (TSPTS), and Other Services (OS) sectors. This study projects that the rising trend in total CO2 emissions will continue from 2022 to 2040 and that emissions will not yet reach their peak by 2030. Furthermore, CO2 emissions from Raw Coal consumption and CO2 emissions from Diesel Oil consumption will continue to increase. These are crucial when designing mitigation schemes for total CO2 emissions. The scenario analysis presents three mitigation schemes for Raw Coal and Diesel Oil emissions that have the potential to reverse the upward trend in CO2 emissions.
Research on the synergizing the reduction of pollution and carbon emissions of new-type urbanization
Authors: Zhao Yuanyuan , Zhou Hongwei , Jiang Chuanzeng , Xuan Linlin , Chen Liming
Published: January 2025

Based on the data of 282 Chinese cities from 2011 to 2018, this article analyzes and explains the synergizing the reduction of pollution and carbon emissions (PCE) of new-type urbanization (NTU) by employing the Differences-in-Differences (DID) model. The results exhibit that the NTU has a significant promoting effect on reducing atmospheric pollutant emissions and improving carbon emission efficiency, demonstrating significant synergistic effects in reducing PCE. This effect varies greatly due to differences in city areas, urban-rural income gap and city scale. Mechanism analysis shows that the NTU mainly affects the synergizing the reduction of PCE by promoting land use structure adjustment and enhancing the level of green technology innovation. Further research indicates that the NTU has a great spatial spillover effect on PCE. This article provides a comprehensive exploration and evaluation of the synergizing the reduction of PCE under the NTU policy. The research findings provide policy insights for reducing air pollutants and carbon dioxide emissions, as well as for advancing the construction of NTU more effectively.