bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibronic coupling in the energetically six lowest electronic states of oxirane radical cation
Authors: Rani Vadala Jhansi , Kanakati Arun Kumar , Mahapatra S.
Published: October 2024

Multi-dimensional quantum mechanical simulations are carried out to understand the multi-state and multi-mode vibronic interactions in the first six low-lying viz., X̃2B1, Ã2A1, B̃2B2, C̃2A2, D̃2A1, and Ẽ2B1 electronic states of c-C2H4O·+. Vibronic coupling theory is applied to study interactions among electronic states using symmetry selection rules. A model 6 × 6 diabatic electronic Hamiltonian is constructed. The parameters of the diabatic Hamiltonian are estimated by performing extensive ab initio electronic structure calculations, using the EOM-IP-CCSD method. The nuclear dynamics calculations are performed with both time-independent and time-dependent quantum mechanical methods. The calculated vibronic structures of six electronic states are found to be in excellent agreement with the available experimental findings. Progressions found in the theoretical spectrum are assigned in terms of vibrational modes. It is found that extremely strong vibronic interactions among the X̃2B1–Ã2A1, B̃2B2–C̃2A2, and D̃2A1–Ẽ2B1 electronic states results into highly overlapping vibronic bands due to multiple multi-state conical intersections. The impact of associated nonadiabatic effects on the vibronic structure and dynamics of the mentioned electronic states is examined at length. Interesting comparison is made with the results obtained for the isomeric acetaldehyde radical cation.
Multi-physics modeling of phase change memory operations in Ge-rich Ge2Sb2Te5 alloys
Authors: Miquel Robin , Cabout Thomas , Cueto Olga , Sklénard Benoit , Plapp Mathis
Published: October 2024

One of the most widely used active materials for phase-change memories (PCM), the ternary stoichiometric compound Ge2Sb2Te5 (GST), has a low crystallization temperature of around 150°C. One solution to achieve higher operating temperatures is to enrich GST with additional germanium. This alloy crystallizes into a polycrystalline mixture of two phases, GST and almost pure germanium. In a previous work [R. Bayle et al., J. Appl. Phys. 128, 185 101 (2020)], this crystallization process was studied using a multi-phase field model (MPFM) with a simplified thermal field calculated by a separate solver. Here, we combine the MPFM and a phase-aware electrothermal solver to achieve a consistent multi-physics model for device operations in PCM. Simulations of memory operations are performed to demonstrate its ability to reproduce experimental observations and the most important calibration curves that are used to assess the performance of a PCM cell.
N-qubit universal quantum logic with a photonic qudit and O(N) linear optics elements
Authors: Delteil Aymeric
Published: October 2024

High-dimensional quantum units of information, or qudits, can carry more than one quantum bit of information in a single degree of freedom and can, therefore, be used to boost the performance of quantum communication and quantum computation protocols. A photon in a superposition of 2N time bins—a time-bin qudit—contains as much information as N qubits. Here, we show that N-qubit states encoded in a single time-bin qudit can be arbitrarily and deterministically generated, manipulated, and measured using a number of linear optics elements that scale linearly with N, as opposed to prior proposals of single-qudit implementation of N-qubit logic, which typically requires O(2N) elements. The simple and cost-effective implementation we propose can be used as a small-scale quantum processor. We then demonstrate a path toward scalability by interfacing distinct qudit processors to a matter qubit (atom or quantum dot spin) in an optical resonator. Such a cavity quantum electrodynamics system allows for more advanced functionalities, such as single-qubit nondemolition measurement and two-qubit gates between distinct qudits. It could also enable quantum interfaces with other matter quantum nodes in the context of quantum networks and distributed quantum computing.
Solar spectral response of photochromic YHO films
Authors: Hansen Per-Anders , Baba Elbruz Murat
Published: October 2024

Photochromic yttrium oxyhydride, YHO, has excellent properties as a responsive solar control material, in particular due to its color-neutral darkening. In this work, we have investigated YHO’s spectral response to the solar AM 1.5 spectrum to evaluate how the total photon activation flux changes as a function of thickness and wavelength. The calculations are based on ellipsometry measurements in the 240–2000 nm range. Our results show that the UV light absorption saturates at around 400 nm thick film, while blue light (>400 nm) continues to provide photoactivation well beyond 1 μm thickness. Understanding the spectral response and absorption per unit time of activating photons as a function of material thickness is important for evaluating the material or coating for applications.
Charge transport in organic semiconductors from the mapping approach to surface hopping
Authors: Runeson Johan E. , Drayton Thomas J. G. , Manolopoulos David E.
Published: October 2024

We describe how to simulate charge diffusion in organic semiconductors using a recently introduced mixed quantum–classical method, the mapping approach to surface hopping. In contrast to standard fewest-switches surface hopping, this method propagates the classical degrees of freedom deterministically on the most populated adiabatic electronic state. This correctly preserves the equilibrium distribution of a quantum charge coupled to classical phonons, allowing one to time-average along trajectories to improve the statistical convergence of the calculation. We illustrate the method with an application to a standard model for the charge transport in the direction of maximum mobility in crystalline rubrene. Because of its consistency with the equilibrium distribution, the present method gives a time-dependent diffusion coefficient that plateaus correctly to a long-time limiting value. The resulting mobility is somewhat higher than that of the relaxation time approximation, which uses a phenomenological relaxation parameter to obtain a non-zero diffusion coefficient from a calculation with static phonon disorder. However, it is very similar to the mobility obtained from Ehrenfest dynamics, at least in the parameter regimes we have investigated here. This is somewhat surprising because Ehrenfest dynamics overheats the electronic subsystem and is, therefore, inconsistent with the equilibrium distribution.
Bulk acoustic wave—Solidly mounted resonator with a-SiOCN:H as low-Z material
Authors: Berger Claudio , Schiek Maximilian , Pandit Shardul , Schneider Michael , Pfusterschmied Georg , Schmid Ulrich
Published: October 2024

Bulk acoustic wave (BAW) filters have been proven to be of high demand in today's low power RF front-ends for mobile communication devices. Within the launch of 5G applications worldwide, especially in the region of new radio (nr-1) up to 6 GHz, defined frequency bands require filters of wide bandwidths, while simultaneously featuring steep edges and high out-of-band rejection. Due to the coexistence with 4G LTE (long term evolution) wireless standards as well as advanced data transfer concepts such as carrier aggregation, the increasing complexity of antenna systems forces the implementation of highly selective acoustic filters. In contrast to the widely used surface acoustic wave (SAW) technology, BAW filters appear with superior performance for frequencies above 1 GHz. This work describes the fabrication of a BAW-solidly mounted resonator (BAW-SMR) with a tailored material system of a-SiOCN:H as a low impedance (low-Z) material integrated within its acoustic Bragg mirror. A direct comparison to the widely used low-Z material of SiO2 with an acoustic impedance of around 13 MRayl is demonstrated by two equal resonator stacks by replacing only the uppermost low-Z thin film of the acoustic reflector. A single-mask design was chosen with platinum as a bottom electrode to ensure the most equal growth conditions for the piezoelectric aluminum nitride (AlN) layers on both reflectors’ surfaces featuring either the tailored a-SiOCN:H or standard SiO2. The a-SiOCN:H thin films were deposited by plasma-enhanced chemical vapor deposition and the according acoustic impedance was priorly depicted to 7.1 MRayl, which could be exploited to achieve an increase in the effective coupling coefficient beyond 7% as well as a resonator bandwidth of more than 60 MHz.
Compressible ocean waves generated by sudden seabed rise near a step-type topography
Authors: Das S. , Pethiyagoda R. , Meylan M. H.
Published: October 2024

A typical tsunami generation occurs through submarine earthquakes leading to large volume displacement. The corresponding mathematical problem involves modeling surface water waves generated by an arbitrary temporal motion of the ocean floor. The propagation of tsunami wave and the subsequent scattering from a sudden drop in bathymetry away from the ground motion is studied following linearized water wave theory and a weakly compressible ocean, including static oceanic background compression. The Fourier transformation and eigenfunction expansion techniques are employed to find the surface displacement and pressure profiles by leveraging appropriate matching conditions between regions of different depths. A novel energy balance relationship is derived by considering both the pure-gravity and acoustic-gravity modes. The model is validated in the limit that the depth difference approaches zero, showing a vanishing reflection contribution from the depth change. An efficient numerical code is developed that accurately captures the contribution of the cutoff frequencies of acoustic-gravity modes. Apart from the time-domain propagation of tsunami waves away from the origin, standing wave formations are observed within the shallow region, supported by significantly large pressure fluctuations in time. These standing waves or, equivalently, the pressure fluctuations sustain longer for larger ocean depth. The increase in tsunami speed in the deeper region is readily visible in the time-domain simulations. A three-dimensional axisymmetric solution is also developed, and results show a more gradual sloping tsunami wavefront compared to the equivalent two-dimensional solution for shallower depths. Animation movies corresponding to the two- and three-dimensional surface profiles are provided for better visualization.
Experimental and numerical study on focused wave generation using different energy modes
Authors: Li Mengyu , Zhao Xizeng , Liu Zhongbo , Lv Chaofan , Lu Jinyou
Published: October 2024

This paper reports an experimental and numerical study on the generation of freak waves related to the spatiotemporal focusing mechanism, where multiple water waves converge at a specific point in space and time to produce a large transient wave. A new energy distribution mode of constant-difference wave number (CDK) within the wave group is proposed and applied to both a physical and a numerical flume to generate focused waves, with primary attention given to the water surface elevation, underlying kinematics, and internal spectrum structure during the focused wave generation process. The classical experiment by Baldock et al. [“A laboratory study of nonlinear surface waves on water,” Philos. Trans. R. Soc., Ser. A 354, 649–676 (1996)], which used a constant-difference wave period within the wave group, is chosen for comparison. Spectral analysis shows that the CDK energy distribution mode can easily stimulate multiwave resonance in the focused wave group, where significant energy transfer from the main frequencies to higher harmonics is observed. Compared with the data from Baldock et al. [“A laboratory study of nonlinear surface waves on water,” Philos. Trans. R. Soc., Ser. A 354, 649–676 (1996)], the CDK wave group produces larger focused wave crests with higher propagation speeds and larger velocity gradients near the water surface due to strong multiwave resonance. The effects of the input spectrum, incident amplitude and initial water depth under different energy modes on focused-wave generation are analyzed. All the results indicate that the CDK energy distribution mode can produce larger focused waves compared to other energy distribution modes, which offers a novel approach for generating freak waves in the laboratory.
Two-dimensional viscous study of coupled nonlinear fluid resonances in two narrow gaps
Authors: Song Zhiwei , Mi Chenglong , Zhou Zhongbing , Gao Junliang , Liu Yingyi
Published: October 2024

The wave-induced hydrodynamics of coupled nonlinear piston-mode fluid resonances within two narrow gaps between three barges are numerically investigated using a two-dimensional viscous wave flume. This study aims to explore the time-dependent nonlinear interactions between fluid oscillations in the two gaps. The coupled synchronous dynamic behaviors of fluid oscillations during the transient evolution stage are first examined in terms of amplitude and frequency modulation. It is shown that phase dynamics, including phase slipping, trapping, and locking, play significant roles in establishing the coupled synchronous dynamic evolutions of fluid oscillations in the two gaps. The quasi-steady state of the amplitude- and phase-frequency responses of fluid oscillations within the gaps, along with the reflection and transmission waves in front of and behind the three-barge system, are further analyzed. This analysis clarifies the significance of viscous damping energy dissipation and radiation damping energy transfer involved in gap resonance problems. This clarification also explains the performance of fully nonlinear potential flow solvers in predicting fluid resonances in the two narrow gaps. Finally, the nonlinear dynamic features of fluid oscillations are examined. The effects of incident wave nonlinearity, i.e., wave steepness, on resonant frequencies, response amplitudes, energy dissipation, and reflection and transmission coefficients are investigated. Harmonic analysis via Fourier transformation reveals the contributions of first-, second-, and third-order harmonics to the overall response amplitudes. The physical insights gained from this study provide a deeper understanding of the coupled nonlinear dynamics of piston-mode fluid resonances in multiple narrow gaps.
Observation of Néel-type magnetic skyrmion in a layered non-centrosymmetric itinerant ferromagnet CrTe1.38
Authors: Pradhan Suman Kalyan , Liu Ying , Zheng Fengshan , Song Dongsheng , Wu Rui
Published: October 2024

Magnetic skyrmions are nanoscale vortex-like magnetization textures that hold great promise for next-generation memory and spintronic devices. While extensive research has focused on discovering such localized spin textures in bulk magnets and multilayers with heavy metals, there is a growing interest in finding them in two-dimensional (2D) magnetic materials. In this research work, we report two distinct phases of the 2D CrxTey family: non-centrosymmetric CrTe1.38 and centrosymmetric CrTe0.96, with a Curie temperature of around 200 and 300 K, respectively. Detailed magnetic study indicates a prominent out-of-plane magnetic anisotropy in CrTe1.38. In contrast, CrTe0.96 exhibits a weak uniaxial magnetic anisotropy. Lorentz transmission electron microscopy shows that the spontaneous ferromagnetic ground state of CrTe1.38 consists of Néel skyrmions, whereas CrTe0.96 exhibits Bloch domain walls, consistent with their crystalline symmetries. This research expands the quasi-2D CrxTey family and opens up new avenues for exploring non-trivial spin structures and their potential applications in spintronic devices.
Permeability evolution of sandstone caprock transverse fractures during intermittent CO2 injection in coal-bearing strata
Authors: Ge Zhao-Long , Huai Qi-Si , Zhou Zhe , Zheng Jing-Wei , Deng Qing-Lin , Jia Yun-Zhong , Liu Chen-Long
Published: October 2024

The caprock of coal-bearing strata plays a critical role in CO2 geological storage, with the presence of fractures posing a heightened risk of CO2 leakage. The cyclic effects of CO2 injection and in situ stress influence the permeability of caprock fractures. However, the combined impact of CO2 and in situ stress on fracture permeability remains uncertain. This study conducted cyclic seepage experiments under varying amplitude stresses on fractured sandstone samples soaked in ScCO2 for different times (0, 15, 30, and 60 days). The microstructural characteristics of the fractured sandstone surfaces were analyzed using scanning electron microscopy and x-ray diffraction. The experimental results indicated that soaking in ScCO2 reduces sandstone fracture permeability, but the extent of this reduction is nonlinearly related to the soaking time. During the stress cycling process, due to the effect of plastic deformation, the permeability of sandstone fractures decreases with increasing cyclic amplitude and remains relatively constant with decreasing cyclic amplitude. At the same cyclic amplitude, the permeability of sandstone fractures initially increases and then decreases with prolonged soaking time. The impact of ScCO2 and stress cycling on the permeability of sandstone fractures is the result of a series of combined chemical–mechanical effects. The combined effects of chemical dissolution and mechanical degradation significantly influence the permeability of sandstone fractures, and this impact is notably time-dependent. During short-term soaking, geochemically induced changes in the surface structure of fractures cause fluctuations in permeability, while in long-term soaking, the combined chemical–mechanical effects promote a reduction in fracture permeability.
Experimental investigation of the swirling steam jet condensation at low mass flux
Authors: Cong Hongchuan , Han Peidong , Zhou Ziqi , Sun Zhongguo , Xi Guang
Published: October 2024

Swirling steam jet condensation holds significant applications in industrial processes such as nuclear safety and gas–liquid mixing in the oxygen transmission pipeline of the liquid rocket engine. However, due to its involvement with complex flow and phase-change heat transfer, the application and optimization of related condensation technologies still face challenges. Therefore, this paper aims to investigate the condensation characteristics of the swirling steam jet by numerous experiments. The steam mass flux is 15–45 kg/(m2·s), and the water temperature ranges from 40 to 85 °C. A novel X-type swirl pressure nozzle is selected to achieve the swirling flow of the steam jet. A comparative analysis is conducted on the interface behavior and evolution of condensation parameters of the non-swirling and swirling steam jets during condensation processes. Results show that the swirling jet condensation includes three flow patterns, namely, chugging regime, smooth grown bubble regime, and rough grown bubble regime. Compared with the non-swirling steam jet condensation, swirling steam jets exhibit a 10.36% increase in the smooth grown bubble regime region and a 14.63% decrease in the rough grown bubble regime. Swirling bubble morphology evolves steadily, and the surface is smoother and more rounded. Simultaneously, irregular deformation behaviors can also occur in the swirling bubble condensation process, such as spiral growth of jet bulge, neck torsion, and the corolla pattern. This deformation helps to increase the contact area and prolongs the bubble lifetime, allowing for more adequate heat transfer at the steam–water interface. The swirling motion of the steam jet will reduce the bubble collapse frequency. As the water temperature rises from 60 to 80 °C, the bubble condensation rate and collapse frequency decrease. The bubble radius increases and the condensation time is extended. With the increasing steam mass flux, the collapse frequency gradually increases. The condensation rate and the bubble radius vary nonlinearly. At the higher steam mass flux, the swirling motion can effectively release the heat that accumulates inside the bubble after reaching the condensation equilibrium state.
Study on the parameter identification of lithium-ion battery model under high-rate pulse discharge conditions
Authors: Hu Taizhuang , Yang Zenghui , Zhang Huibo , Zhang Zicheng
Published: October 2024

With the rapid development of the new energy sector and lithium-ion (Li-ion) battery technologies, using Li-ion batteries with high energy density and high discharge rate to form the primary energy subsystem can further improve the compactness and miniaturization level of pulsed power systems. In traditional electric power systems, Li-ion batteries normally operate under the discharge condition of low current and long time. However, as the main power source of pulsed power systems, it is required that Li-ion batteries should have the capability for high-rate pulse discharge. To ensure the safe and reliable operation of the battery energy storage system, it is necessary to conduct the parameter identification of the Li-ion battery model to establish an accurate pulse discharge model under such working conditions. This paper focuses on the discharge characteristics of a cylindrical high-rate single Li-ion battery with a capacity of 3 Ah. At a 20 C rate, the discharge data were obtained when the pulse repetition frequency was 10 Hz and the duty cycle was 90%. By using the mathematical expressions of the Thevenin equivalent circuit model, the recursive relationship of the circuit parameters was obtained, and the parameter identification of the battery model was conducted based on the experimental data by using the genetic algorithm. The results show that the fitting accuracy of the parameter identification reaches 0.9995, indicating the high precision of the model for the Li-ion battery. This work provides a significant reference for the modeling and parameter identification of Li-ion batteries under high-rate pulse discharge conditions.
Experimental study on the influence of surface properties on droplet collision dynamics, from adhesion to rebound to breakup
Authors: Zhu Junhao , Wang Zhongyi , Dai Zheng , Wang Yanhua , Wang Meng , Chen Haoran , Sun Yixin
Published: October 2024

Liquid droplet impact on dry surfaces often results in bouncing or breakup beyond a certain threshold. Surface contact angles, especially dynamic ones present during impact, significantly affect this process. Our experimental study underscores that advancing and receding contact angles influence droplet behaviors like rebounding and different types of breakup. This discovery provides new insights and criteria for understanding liquid droplet impact on surfaces. Special characteristics were found in the breakup on microstructured surfaces: the size of fractured droplets notably decreases, and the spreading–breakup occurs more easily and earlier. Additionally, microstructured surfaces reduce contact time to some extent. Furthermore, the uniqueness of oblique impacts is mainly reflected in how they lower the threshold of the receding contact angle for rebound. Studying the correlations and differences in droplet rebound and breakup related to these surface characteristics will contribute to improving research on liquid–solid interactions and the design of hydrophobic surfaces, including microstructured surfaces.
Aging affects the mechanical interaction between microplastics and lipid bilayers
Authors: Fleury Jean-Baptiste , Baulin Vladimir A.
Published: October 2024

Plastic pellets, the pre-production form of many plastic products, undergo oxidation and photodegradation upon exposure to oxygen and sunlight, resulting in visible color changes. This study examines the impact of environmental aging on the mechanical interactions between pellet-derived microplastics and lipid bilayers, a critical component of biological membranes. Polyethylene pellets were collected from La Pineda beach near Tarragona, Spain, and categorized by chemical composition and yellowing index, an indicator of aging. The hydrophilicity of these pellets was assessed using contact angle measurements. Microplastics were produced by grinding and filtering these pellets and subsequently dispersed around a free-standing lipid bilayer within a 3D microfluidic chip to investigate their interactions. Our results reveal that aged microplastics exhibit a significantly increased adhesive interaction with lipid bilayers, leading to greater bilayer stretching. Theoretical modeling indicates a linear relationship between the adhesive interaction and the contact angle of the pellets, reflecting their hydrophilicity. These findings emphasize the increased mechanical impact of aged microplastics on biological membranes, which raises concerns about their potential toxicological effects on living organisms. This study highlights the importance of understanding the interactions between environmentally aged microplastics and biological systems to assess their risks, as these may differ significantly from pristine microplastics often studied under laboratory conditions.
Enhancing the two-layer k-epsilon turbulence model through rough wall modification
Authors: Ma Haoran , Chen Hamn-Ching
Published: October 2024

Surface roughness significantly influences turbulence structures, affecting skin friction and velocity profiles. Precisely modeling the roughness effects is essential for reliable numerical simulation results in various engineering applications. This paper introduces enhancements to the two-layer k-epsilon (k−ε) turbulence model, incorporating surface roughness effects by adjusting variables in prescribed length scales and turbulent boundary conditions and ensuring the model switches between different roughness regimes. The accuracy of the enhanced model was validated using the Grigson–Colebrook type roughness function and experimental data from flat plate flows, as well as more complex geometries such as sand dune flow and ramp flow. The modified model demonstrated strong agreement with experimental data, accurately predicting the effects of roughness across diverse flow conditions, particularly in terms of velocity profiles. The proposed roughness modifications substantially improve the model's capability to simulate turbulent flows over rough surfaces, providing a valuable tool for predicting flow behavior in engineering applications involving rough surfaces.
Triple-top-gate technique for studying the strongly interacting 2D electron systems in heterostructures
Authors: Melnikov M. Yu. , Shashkin A. A. , Huang S.-H. , Liu C. W. , Kravchenko S. V.
Published: October 2024

We have developed a technique that dramatically reduces the contact resistances and depletes a shunting channel between the contacts outside the Hall bar in ultra-high mobility SiGe/Si/SiGe heterostructures. It involves the creation of three overlapping independent gates deposited on top of the structure and allows transport measurements to be performed at millikelvin temperatures in the strongly interacting limit at low electron densities, where the energy of the electron–electron interactions dominates all other energy scales. This design allows one to observe the two-threshold voltage–current characteristics that are a signature for the collective depinning and sliding of the electron solid.
Structure optimal design of 500 kV dry-type air-core shunt reactor based on response surface method
Authors: Zhu Yanjing , Kou Jiajun , Zhang Zhiyu , Liu Gang , Hu Wei , Xie Liang , Zhou Guangdong
Published: October 2024

The hotspot temperature of the reactor is one of the important indices in reactor design, and the appropriate hotspot value can ensure that the reactor will not overheat failure and threaten the safety of the power system. In this paper, the temperature field simulation model of a 500 kV dry-type air-core shunt reactor is established, and the hotspot temperature of the reactor is obtained by COMSOL software. Then, the radial basis function response surface function is used to construct the response surface function of the hotspot temperature and its related variables, and the applicability of the response surface function is tested to analyze the rationality and accuracy of the response surface function. Finally, the optimal solution of the response surface function under the coordination of variables and related constraints is obtained by using the constrained simulated annealing algorithm. The results show that the hotspot temperature of the reactor envelope winding decreases obviously after optimization.
Human tissue-resident NK cells in the lung have a higher glycolytic capacity than non-tissue-resident NK cells in the lung and blood
Authors: Jameson Gráinne , Walsh Aaron , Woods Robbie , Batten Isabella , Murphy Dearbhla M. , Connolly Sarah A. , Duffin Emily , O’Gallchobhair Oisin , Nadarajan Parthiban , O’Connell Finbarr , Gleeson Laura E. , Keane Joseph , Basdeo Sharee A.
Published: October 2024

Tissue-resident natural killer (trNK) cells are present in the human lung, yet their metabolic function is unknown. NK cell effector and metabolic function are intrinsically linked therefore targeting metabolism presents therapeutic potential in supporting NK cell effector function. This study identifies trNK cells in human bronchoalveolar lavage fluid (BALF) and reveals their distinct metabolic function. To assess the differential phenotype and metabolism of NK cells in the lung, human BALF, and peripheral blood were evaluated by flow cytometry and SCENITH
TM
. Published RNA-sequencing datasets of human lung and blood NK cells were repurposed to determine their differential gene expression. We identified CD49a
+
CD69
+
CD103
+/−
CD56
bright
CD16
−
trNK cells in human BALF samples and metabolic profiling revealed that lung CD56
bright
CD16
−
NK cells’ glycolytic capacity and dependence on glucose is significantly higher than matched peripheral blood counterparts. This high glycolytic capacity and glucose dependence was attributed to the trNK cell subset which supports the existing evidence that they have an enhanced ability to respond in the lung.
Update of the BIPM comparison BIPM.RI(II)-K1.Ga-67 of activity measurements of the radionuclide 67Ga to include the 2023 result of the CMI (Czechia)
Authors: Michotte Carine , Courte Sammy , Coulon Romain , Nonis Manuel , Sochorová J , Auerbach P
Published: October 2024

Main text

Since 1978, 10 laboratories have submitted 18 samples of 67Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. Recently, the CMI (Czechia) participated in the comparison and the key comparison reference value (KCRV) has been fully revised. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
High contrast computational imaging with vortex phase diversity
Authors: Singh Mahendra Pratap , Pandey Neeraj , Khare Kedar
Published: October 2024

Optical imaging systems employing spatially incoherent illumination are widely used in routine imaging applications like photography and bright-field microscopy. We describe an incoherent computational imaging system that uses an open aperture as well as a vortex phase aperture for recording the same scene. The two raw recorded images provide a diversity of information that can be effectively combined using the generalized Wiener filter. For the specific choice of aperture functions used here, the two corresponding generalized Wiener filters have nearly opposing polarity. This property leads to an effective computational point spread function (PSF) whose central lobe is 0.6 times smaller compared to the diffraction-limited PSF and has a super-oscillatory character with side-lobes. The resultant computational imaging system provides images with significantly improved contrast. While our methodology requires two image records, the enhanced PSF with super-oscillatory character is obtained by employing bulk off-the-shelf optical elements instead of sub-wavelength structured masks. The vortex phase diversity concept along with computational image reconstructions are illustrated with both simulation and experimental data. The proposed imaging methodology may be used to improve imaging performance for wide ranging imaging systems without changing their form factor.
Review on chemical mechanical polishing for atomic surfaces using advanced rare earth abrasives
Authors: Chen Xiangyan , Zhang Zhenyu , Zhao Feng , Luo Hao , Wang Jianmei , Meng Fanning , Zhou Hongxiu , Zhuang Xuye , Li Guo
Published: October 2024

During the past decades, high-performance devices and setups have been widely used in the fields of precision optics, semiconductors, microelectronics, biomedicine, optoelectronics and aerospace. It is a challenge to achieve ultralow surface roughness free of damages. Due to the unique physicochemical properties of rare earths, ceria has garnered great progresses for atomic surfaces induced by chemical mechanical polishing. Compared with conventional mechanical removal by alumina and silica, rare earth abrasives achieve selective material removal on surface via their special chemical activity, without introducing microscopic scratches and defects. Nevertheless, polishing performance of rare earth abrasives depends on series of factors, e.g. size of abrasive particles, microscale topological structure, configuration of chemical slurry, auxiliary energy fields etc. As a result, it is significant to conduct a comprehensive review to understand state-of-the-art polishing technologies. This review summarizes the effect of polishing slurries composed of different rare earth abrasives on polishing performance under different conditions. Additionally, various energy-assisted polishing strategies are discussed using diverse kinds of rare earth abrasives for distinct polishing forms. Finally, future directions of polishing on rare earth abrasives are addressed.
Research on tire appearance defect detection algorithm based on efficient multi-scale convolution
Authors: Gao Zhangang , Yang Zihao , Xu Mengchen , Yang Hualin , Deng Fang
Published: October 2024

Due to the large randomness of tire appearance defect size and the complex and diverse defect shapes, the existing target detection algorithm is prone to missing and misidentifying targets, the accuracy is limited, and the detection model is large, which is not conducive to deployment on embedded devices. In this paper, the efficient multi-scale convolution (EMC) mode is proposed, and the C2f-EMC module is designed on this basis, which improves the network structure of YOLOv8, improves the accuracy of tire appearance defect detection, and reduces the number of parameters in the model. EMC convolution first divides the input feature images into four parts on average and carries out multi-scale convolution with convolution cores of 1 × 1, 3 × 3, 5 × 5 and 7 × 7 sizes respectively. Then, the obtained results are stacked, and cross-channel feature fusion is realized by point-by-point convolution. After determining the network structure of C2f-EMC, the best improvement position of C2f-EMC module is determined through comparative experiments. Experiments show that after the above improvements, the parameter number of the model is reduced by 4.85%, the calculation amount by 2.82%, the model size by 4.44%, the recall rate by 2.8%, the mAP50 by 1.0%, the mAP50-95 by 1.3%, and the F1 by 2%. The defect detection task can be completed more accurately and the model size requirements of embedded devices can be better met.
Sub-∘C-precision temperature imaging using phase-shift luminescence thermometry
Authors: López Bonilla Joel , Beyrau Frank , Fond Benoit
Published: October 2024

This work explores the potential of luminescence thermometry to provide temperature imaging with high temperature resolution using the phase-shift method. Phosphor thermometry has been widely used for temperature imaging, especially with the decay-time method. However, the phase-shift method was rarely used. In this approach, excitation is modulated in time, and due to the temperature-dependent luminescence dynamics of the painted luminescent probe, the emission waveform is phase-shifted with respect to the excitation waveform. Initially, a parametric study was performed on the effect of excitation waveform frequency and shape, based on a millisecond-decay time phosphor. The study found that the best precision is achieved with a square waveform at a frequency such that the phase shift is

π
4

at the target temperature. Then, this method was compared with the well-established decay-time method. Phase-shift method offered a three-fold improvement in temperature precision under identical peak excitation power. Finally, two-dimensional measurements were demonstrated on a temperature-controlled plate using a high speed CMOS camera, and an LED illumination. A temperature precision of 0.13 ∘C was obtained at a temporal resolution of 0.25 s and a spatial resolution of around 1 mm, due to a pre-processing binning of 7 by 7 pixels. This technique can be used as a robust alternative to infrared thermometry to probe the thermal processes with small temperature differences.
Integrable flows on null curves in the Anti-de Sitter 3-space
Authors: Musso Emilio , Pámpano Álvaro
Published: October 2024

We formulate integrable flows related to the Korteweg–De Vries (KdV) hierarchy on null curves in the anti-de Sitter 3-space (

AdS

). Exploiting the specific properties of the geometry of

AdS

, we analyze their interrelationships with Pinkall flows in centro-affine geometry. We show that closed stationary solutions of the lower order flow can be explicitly found in terms of periodic solutions of a Lamé equation. In addition, we study the evolution of non-stationary curves arising from a 3-parameter family of periodic solutions of the KdV equation.
Continuously tunable single-photon level nonlinearity with Rydberg state wave-function engineering
Authors: Xu Biao , Ye Gen-Sheng , Chang Yue , Shi Tao , Li Lin
Published: October 2024

Extending optical nonlinearity into the extremely weak light regime is at the heart of quantum optics, since it enables the efficient generation of photonic entanglement and implementation of photonic quantum logic gate. Here, we demonstrate the capability for continuously tunable single-photon level nonlinearity, enabled by precise control of Rydberg interaction over two orders of magnitude, through the use of microwave-assisted wave-function engineering. To characterize this nonlinearity, light storage and retrieval protocol utilizing Rydberg electromagnetically induced transparency is employed, and the quantum statistics of the retrieved photons are analyzed. As a first application, we demonstrate our protocol can speed up the preparation of single photons in low-lying Rydberg states by a factor of up to

∼

40

. Our work holds the potential to accelerate quantum operations and to improve the circuit depth and connectivity in Rydberg systems, representing a crucial step towards scalable quantum information processing with Rydberg atoms.
Cosmological implications on two fluids model universe with parametrization of Hubble parameter in Lyra manifold
Authors: Sabanam Syed , Singh Kangujam Priyokumar
Published: October 2024

In this research, we explore the cosmological implication on five-dimensional FRW cosmological model for k = 0 in presence of two perfect fluids: ordinary baryonic fluid and an interacting dark energy in the context of Lyra’s manifold. We obtain an exact solution of the field equations by assuming the parametrization of the Hubble parameter H(a) = τ(1 + a
−ν
), where a is a scale factor and τ > 0, ν > 1 are the arbitrary constants. This results in a universe model with a transition from a previously decelerating universe to the current accelerating universe, characterized by a time-dependent deceleration parameter. Moreover, we have used 46 observational Hubble data sets to restrict the parameters of our suggested model. Some cosmological parameters have been examined about the nature of the proposed model universe. It is shown that our model can be considered a realistic one.
Effects of DM and KSEA interactions on entanglement, Fisher and Wigner-Yanase information correlations of two XYZ-Heisenberg-qubit states under a magnetic field
Authors: Gaidi S , Slaoui A , Mohamed A-B A , EL Falaki M , Ahl Laamara R
Published: October 2024

We employ entanglement negativity, local quantum uncertainty (LQU), and local quantum Fisher information (LQFI) to characterize thermal entanglement between two XYZ-Heisenberg-qubit states under the influence of Dzyaloshinsky-Moriya(DM) and Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) interactions, as well as a magnetic field and thermal equilibrium temperature. A comparative examination reveals similar behaviors among these correlation measures. For the antiferromagnetic scenario, we observe that increasing the DM interaction parameter D

z
enhances thermal entanglement. Conversely, in the ferromagnetic case, the behavior of thermal entanglement differs with varying D

z
. Additionally, employing Kraus operators, we explore the performance of these quantifiers under decoherence. Notably, LQFI exhibits greater robustness than negativity and LQU, even displaying a frozen phenomenon at some time under dephasing effects.
Entanglement manipulation through multicore fibres
Authors: Marconi Carlo , Fanella Elena , Bacco Davide , Zavatta Alessandro
Published: October 2024

Multicore fibres are recently gaining considerable attention in the context of quantum communication, where their capability to transmit multiple quantum states along different cores of the same channel makes them a promising candidate for the implementation of scalable quantum networks. Here, we show that multicore fibres can be effectively used not only for the scope of communication but also for the manipulation of entangled states. Exploiting the formalism of completely positive trace-preserving maps, we describe the action of a multicore fibre as a quantum channel and investigate the propagation of a transmitted state under the effect of decoherence and inter-core crosstalk. Then, we propose a novel protocol for the manipulation of the entanglement where, starting from a maximally entangled state of two qudits, we use a multicore fibre to create new families of mixed entangled states. Notably, the presence of crosstalk is fundamental for the generation of such states.
A fractional order mathematical model for the omicron: a new variant of COVID-19
Authors: Diyar Raham , Ahmad Imtiaz , Ali Nigar , Haq Ihtisham Ul , Idrees Mohammad , Daher Albalwi Mohammed
Published: October 2024

For the purpose of analyzing the Omicron pandemic, we build a novel

S
E

I

a

I

s

I

o

H
R

mathematical model. The fundamental properties of the model are studied, including boundedness, uniqueness, and existence. The boundedness of the model’s solution is examined by solving the fractional Gronwall’s inequality using the Laplace transform method. Using the Picard-Lindelöf theorem, we verify the solution’s existence and uniqueness. The next-generation matrix is used to compute

R

o

(the basic reproduction number), which is significant in the mathematical modeling of infectious diseases. It is demonstrated that both the endemic and disease-free equilibrium solutions are globally and locally asymptotically stable. We also conducted a sensitivity analysis of the parameters based on

R

o

. Moreover, the model is extended by employing optimal control theory to examine the effects of certain control strategies. Finally, numerical simulations are performed to validate the model.
curvature-squared corrections on Langevin diffusion coefficients*
Authors: Zhou 周 Qi 琪 , Zhang 张 Ben-Wei 本威
Published: October 2024

The effect of finite coupling corrections to the Langevin diffusion coefficients on a moving heavy quark in the Super Yang-Mills plasma was investigated. These corrections are related to curvature squared corrections in the corresponding gravity sector. We compared the results of both longitudinal and perpendicular Langevin diffusion coefficients with those for

=4 Super Yang-Mills plasma. It was observed that the curvature-squared corrections influence the Langevin diffusion coefficients, and the corrections for both Langevin diffusion coefficients demonstrate the dependence on the velocity of the moving heavy quark and the specifics of the higher derivative correction. In addition, we conducted calculations for the Langevin diffusion coefficients of a moving heavy quark within the Gauss-Bonnet background.
ISMGCC: Finding Gas Structures in Molecular Interstellar Medium Using Gaussian Decomposition and Graph Theory
Authors: Feng Haoran , Chen Zhiwei , Jiang Zhibo , Urquhart James S.
Published: October 2024

Molecular line emissions are commonly used to trace the distribution and properties of molecular Interstellar Medium. However, the emissions are heavily blended on the Galactic disk toward the inner Galaxy because of the relatively large line widths and the velocity overlaps of spiral arms. Structure identification methods based on voxel connectivity in Position-Position-Velocity (PPV) data cubes often produce unrealistically large structures, which is the “over-linking” problem. Therefore, identifying molecular cloud structures in these directions is not trivial. We propose a new method based on Gaussian decomposition and graph theory to solve the over-linking problem, named InterStellar Medium Gaussian Component Clustering (ISMGCC). Using the Milky Way Imaging Scroll Painting (MWISP) 13CO(1–0) data in the range of 13.°5 ≤ l ≤ 14.°5, ∣b∣ ≤ 0.°5, and −100 ≤ V
lsr ≤ +200 km s−1, our method identified three hundred molecular gas structures with at least 16 pixels. These structures contain 92% of the total flux in the raw data cube and show single-peaked line profiles on more than 93% of their pixels. The ISMGCC method could distinguish gas structures in crowded regions and retain most of the flux without global data clipping or assumptions on the structure geometry, meanwhile, allowing multiple Gaussian components for complicated line profiles.
A smooth switching strategy for steady-state operation control and fault transient control of doubly fed induction generator
Authors: Zhuang Shenglun , Kong Xiangmei , Qu Huixing , Sun Sujuan
Published: October 2024

As the proportion of wind power generation systems in power systems continues to rise, their dynamic response during system malfunctions has gained significant importance. As the grid short-circuit ratio continues to decrease, traditional fault ride-through algorithms for wind power generators may no longer be applicable. This is evidenced by voltage oscillations under significant disturbances and overvoltage issues during low-voltage ride-through, which are further aggravated during asymmetric fault conditions. Therefore, this paper focuses on the low-voltage ride-through issues of doubly fed induction wind power generators in weak power grids. It investigates the steady-state operation and transient control schemes and proposes a smooth transition strategy for steady-state and fault transient operations of doubly fed wind power generators. This approach guarantees the synchronization of active and reactive power, mitigates steady-state reactive power imbalance, and prevents voltage fluctuations triggered by recurring low-voltage ride-through occurrences. Furthermore, during fault recovery, a ramped active power restoration approach is employed to mitigate the coupling of active and reactive power introduced by the phase-locked loop, enabling rapid and stable restoration of active and reactive power outputs. As a result, superior dynamic performance is achieved during both symmetric and asymmetric fault processes. Finally, the superiority of the proposed smooth transition strategy under different fault scenarios is validated through simulations with the RTLAB platform.