bluuebunny/crossref_metadata_2025 huggingface dataset:
Heart health prediction and classification: An IoMT and AI collaborative model
Authors: Sundar R. , Gangopadhyay Amit , Gupta T. Raghavendra , Murthy P.L. Srinivasa , Gogula Sreenivasulu , Sharath M.N. , Muppavaram Kireet
Published: March 2024

Internet of Things (IoT) technology has been used in medical care as the Internet of Medical Things (IoMT) to gather sensor data for diagnosing and predicting cardiac disease. IoMT allows users to access real-time tracking information and manually estimate the person's health using Machine Learning (ML) algorithms. The primary goal of the study proposal is to categorize data and forecast heart illness using health information and medical imagery. The suggested IoMT-based Heart Health Prediction and Classification (IoMT-HHPC) model is a medical data categorization and forecasting framework in two phases. If the first stage's outcome effectively predicts heart disease, the second step is image classification. Data collected from medical equipment attached to the person's body were initially categorized. Echocardiography (ECG) images were analyzed to forecast cardiac problems. This article used many ML techniques to forecast cardiac disease. An IoMT-HHPC model with ANN achieved an accuracy of 99.02%, surpassing the performance of other ML algorithms.
Morphology, electrical & optical properties of BaO thin films deposited by PVD
Authors: Laouid Amina , Alaoui Belghiti Amine , Wisniewski Krzysztof , Tlemçani Mouhaydine , Płóciennik Przemysław , Hajjaji Abdelowahed , Zawadzka Anna
Published: March 2024

In this work, we explore a new experimental study of Barium oxide (BaO) thin films, fabricated using the physical vapor deposition (PVD) technique on both glass and silicon substrates. The BaO thin films have emerged as highly adaptable materials with immense potential across multiple technological domains. The investigation focuses on the morphological, optical, and electrical properties of BaO thin films to determine their potential for various applications. These films, consistently tailored to a thickness of 100 nm, exhibit exceptional optical properties, boasting an impressive transmittance rate of up to 90%. This makes them exceptionally well-suited for applications that demand superior optical transmission, such as flat-panel displays, photovoltaic devices, and various optoelectronic applications. The films’ low roughness values, measured at 6.31 nm for glass-deposited films and 13.32 nm for silicone-deposited ones, underscore their uniformity, ensuring stable and precise performance control in diverse applications. Further underscoring their versatility is the wide energy gap of 2.93 eV, suggesting their potential utility in advanced optoelectronic devices that require higher energy levels. In addition to their optical prowess, BaO thin films exhibit impressive electrical resistance, measuring at 3.3 × 108 ohms, rendering them promising candidates for specialized applications, including pressure and humidity sensors, as well as electrical insulation devices. Overall, these films represent an exciting avenue for addressing specific technological needs and driving innovation in the realm of thin film technology.
Empowering optimal transport matching algorithm for the construction of surrogate parametric metamodel
Authors: Jacot Maurine , Champaney Victor , Torregrosa Jordan Sergio , Cortial Julien , Chinesta Francisco
Published: March 2024

Resolving Partial Differential Equations (PDEs) through numerical discretization methods like the Finite Element Method presents persistent challenges associated with computational complexity, despite achieving a satisfactory solution approximation. To surmount these computational hurdles, interpolation techniques are employed to precompute models offline, facilitating rapid online solutions within a metamodel. Probability distribution frameworks play a crucial role in data modeling across various fields such as physics, statistics, and machine learning. Optimal Transport (OT) has emerged as a robust approach for probability distribution interpolation due to its ability to account for spatial dependencies and continuity. However, interpolating in high-dimensional spaces encounters challenges stemming from the curse of dimensionality. The article offers insights into the application of OT, addressing associated challenges and proposing a novel methodology. This approach utilizes the distinctive arrangement of an ANOVA-based sampling to interpolate between more than two distributions using a step-by-step matching algorithm. Subsequently, the ANOVA-PGD method is employed to construct the metamodel, providing a comprehensive solution to address the complexities inherent in distribution interpolation.
Rendre « vilisible » l’écriture scolaire. Choix de transcription et d’annotation pour une mise en corpus
Authors: Doquet Claire , Ponton Claude
Published: March 2024

Cet article expose les bases théoriques et méthodologiques du corpus E-CALM. Ce corpus a été construit pour répondre à la nécessité de documenter les compétences scripturales des élèves en France à différents niveaux de la scolarité. E-CALM constitue un réservoir de données textuelles exploitables par la recherche et par la formation des enseignants. Les choix de traitement des manuscrits recueillis ont permis de faire émerger les traces de l’écriture des élèves et de leurs interactions avec les enseignants corrigeant et commentant les copies. Explorer avec des outils informatiques un grand corpus d’écrits scolaires permet de confirmer des connaissances déjà acquises mais aussi de faire apparaitre des éléments nouveaux, invisibles à l’observation de données de faibles tailles et qu’un grand corpus tel qu’E-CALM (plus d’un million de mots) permet de révéler. Une fois produite, l’analyse linguistique conduit à des avancées didactiques : en faisant émerger des éléments discriminants des textes, corrélés à des variables didactiques et sociologiques, elle permet de proposer des protocoles d’enseignement ajustés aux contextes d’apprentissage.
Meromorphic Functions Sharing Two Values
Authors: ZHAO Ying , HUANG Zhigang
Published: March 2024

Let [see formula in PDF] and [see formula in PDF] be two nonconstant meromorphic functions, and [see formula in PDF] be a positive integer. If [see formula in PDF] and [see formula in PDF] share 1 CM (counting multiplicities), [see formula in PDF] and [see formula in PDF] share [see formula in PDF] IM (ignoring multiplicities), and [see formula in PDF], then either [see formula in PDF] or [see formula in PDF], where [see formula in PDF]. As an application, shared values problems of a meromorphic function related to its shifts and difference operators are also investigated.
Uniform Asymptotics for Finite-Time Ruin Probabilities of Risk Models with Non-Stationary Arrivals and Strongly Subexponential Claim Sizes
Authors: XU Chenghao , WANG Kaiyong , PENG Jiangyan
Published: March 2024

This paper considers the one- and two-dimensional risk models with a non-stationary claim-number process. Under the assumption that the claim-number process satisfies the large deviations principle, the uniform asymptotics for the finite-time ruin probability of a one-dimensional risk model are obtained for the strongly subexponential claim sizes. Further, as an application of the result of one-dimensional risk model, we derive the uniform asymptotics for a kind of finite-time ruin probability in a two dimensional risk model sharing a common claim-number process which satisfies the large deviations principle.
A Full-Newton Step Feasible Interior-Point Algorithm for the Special Weighted Linear Complementarity Problems Based on a Kernel Function
Authors: GENG Jie , ZHANG Mingwang , ZHU Dechun
Published: March 2024

In this paper, a new full-Newton step primal-dual interior-point algorithm for solving the special weighted linear complementarity problem is designed and analyzed. The algorithm employs a kernel function with a linear growth term to derive the search direction, and by introducing new technical results and selecting suitable parameters, we prove that the iteration bound of the algorithm is as good as best-known polynomial complexity of interior-point methods. Furthermore, numerical results illustrate the efficiency of the proposed method.
Influence of Kerr Effect on Second-Order Nonlinearity Induced Transparency
Authors: ZHANG Zhiqiang , ZHOU Yanhui
Published: March 2024

We theoretically study the effect of Kerr effect on the second-order nonlinearity induced transparency in a double-resonant optical cavity system. We show that in the presence of the Kerr effect, as the strength of the Kerr effect increases, the absorption curve exhibits an asymmetric-symmetric-asymmetric transition, and the zero absorption point shifts with the increase of the Kerr effect. Furthermore, by changing the strength of the Kerr effect, we can control the width of the transparent window, and the position of the zero-absorption point and meanwhile change the left and right width of the absorption peak. The asymmetry absorption curve can be employed to improve the quality factor of the cavity when the frequency detuning is tuned to be around the right peak. The simple dependence of the zero-absorption point on the strength of Kerr effect suggests that the strength of Kerr effect can be measured by measuring the position of the zero-absorption point in a possible application.
Deteriorating Semen Quality: The Role of the Environment
Authors: Virtanen Helena E. , Rodprasert Wiwat , Toppari Jorma
Published: March 2024

Since the end of the last century, several reports have suggested that semen quality is declining, especially in Western countries. Furthermore, cross-sectional studies using similar protocols have suggested regional differences in semen quality of young and fertile men. Reasons for these regional differences and local adverse trends in semen quality are unknown, but environmental factors are suspected to have a role. Besides adulthood environmental exposures, those occurring during testicular development may also affect semen quality. Longitudinal follow-up studies and mixture risk analyses are needed to study the effect of fetal, childhood, and adult life environment on semen quality.
Analytic structure of the associated Legendre functions of the second kind
Authors: Liu Tianye , Norman Daniel A. , Mannheim Philip D.
Published: March 2024

We consider the complex ν plane structure of the associated Legendre functions of the second kind Qν−1/2−K(cosh⁡ρ). We find that for any noninteger value of K the Qν−1/2−K(cosh⁡ρ) have an infinite number of poles in the complex ν plane, but for any negative integer K there are no poles at all. For K = 0 or any positive integer K there is only a finite number of poles, with there only being one single pole (at ν = 0) when K = 0. This pattern is analogous to the pattern of exceptional points that appear in a wide variety of physical contexts. However, while theories with exceptional points usually lose a finite number of degrees of freedom at the exceptional points, the Qν−1/2−K(cosh⁡ρ) lose an infinite number of poles whenever K is integer. Moreover, while theories with exceptional points usually have a finite number of such exceptional points, the Qν−1/2−K(cosh⁡ρ) possess an infinite number of points (all integer K) at which they lose degrees of freedom. Other than in the PT-symmetry Jordan-block case, exceptional points usually occur at complex values of parameters. While not being Jordan-block exceptional points themselves, the poles associated with the Qν−1/2−K(cosh⁡ρ) nonetheless occur at real values of K.
On topological obstructions to the existence of non-periodic Wannier bases
Authors: Kordyukov Yu. , Manuilov V.
Published: March 2024

Recently, Ludewig and Thiang introduced a notion of a uniformly localized Wannier basis with localization centers in an arbitrary uniformly discrete subset D in a complete Riemannian manifold X. They show that, under certain geometric conditions on X, the class of the orthogonal projection onto the span of such a Wannier basis in the K-theory of the Roe algebra C*(X) is trivial. In this paper, we clarify the geometric conditions on X, which guarantee triviality of the K-theory class of any Wannier projection. We show that this property is equivalent to triviality of the unit of the uniform Roe algebra of D in the K-theory of its Roe algebra, and provide a geometric criterion for that. As a consequence, we prove triviality of the K-theory class of any Wannier projection on a connected proper measure space X of bounded geometry with a uniformly discrete set of localization centers.
Predicting shear stress distribution on structural surfaces under internal solitary wave loading: A deep learning perspective
Authors: Zhang Miao , Hu Haibao , Guo Binbin , Liang Qianyong , Zhang Fan , Chen Xiaopeng , Xie Zhongliang , Du Peng
Published: March 2024

The density of the ocean varies unevenly along the vertical axis. In the presence of external disturbances, internal solitary waves (ISWs) are generated. The strong shear flow field induced by ISW seriously threatens the operational safety of marine structures. Therefore, it has become a hot spot to study the force law of marine structures in ISW. The existing studies are conducted when the ISW parameters are known. However, ISW is not visible in real situations, which leads to difficulties in obtaining ISW parameters. Therefore, it is of great engineering value to accomplish real-time force prediction of marine structures without knowing the ISW parameters in advance. To fill the gap, this study proposes a novel hydrodynamic prediction model with a sensor array as the sensing system and a deep learning algorithm as the decision-making system. The model successfully achieves accurate prediction of the shear stress on the cylinder in the ISW. In addition, a technique for optimizing sensor placement is proposed. This will help identify critical regions in the graphical representations to enhance exploration of flow field information. The results demonstrate that the prediction accuracy of the optimized sensor layout scheme surpasses that of randomly deployed sensors. As a result, this study will provide an important assurance for the safe operation of marine structures.
A lattice Boltzmann model for incompressible gas and liquid two-phase flows combined with free-surface method
Authors: Liu Yilin , Sun Dongke , Zhang Zexin , Chen Wei
Published: March 2024

A novel lattice Boltzmann (LB) model is proposed to study the gas and liquid two-phase flows with large density and viscosity ratios. In the model, both the gas and liquid phases are considered as viscous incompressible fluids, which are governed separately by the two-relaxation-time LB equations. They are coupled by a momentum exchange method at the interface. The interaction between the gas and liquid phases is explicitly described and naturally involved in the model. The interfacial conditions in the model are validated by the benchmarks of the layered Poiseuille flow and the Laplace law. The feasibility of combining this model with the bubble model and the wetting scheme is proven through transient flow problems of single bubble rising and capillary intrusion. The validity of this model is confirmed by more complex flows including solid–liquid–gas coupling and droplet breaking problems by simulating shearing a droplet on a substrate and a droplet falling on a liquid film. The results demonstrate that the present model can be used to describe both the gas and the liquid flows. This work provides a solution to model the simulation of the dynamical behaviors of multi-phase flows.
An improved semi-resolved computational fluid dynamics-discrete element method for simulating liquid–solid systems with wide particle size distributions
Authors: Wen Xiaojiang , Zheng Lingna , Zhao Xun , Liu Yingke , Kang Jianhong , Ye Guoqing , Wang Fengchao , Yuan Man , Jiang Mingjun
Published: March 2024

Vertical hydraulic transport of particles with wide particle size distributions is a crucial process for coal physical fluidized mining. In the present study, an improved semi-resolved computational fluid dynamics (CFD)-discrete element method was developed to simulate particle flows with wide particle size distributions. In this model, the CFD cells allocated to the particle volume and the momentum source term were defined as the dependent domain and the influential domain, respectively. On this basis, the two-way domain expansion method and the one-way domain expansion method were adopted for the liquid–solid simulation of coarse and fine particles, respectively. The dependent domain expansion coefficient and the influential domain expansion coefficient were proposed to determine the spatial range of the dependent domain and influential domain for the coarse particles, and the optimal modeling strategy for the dependent domain and influential domain expansion coefficient for the coarse particles was determined. Furthermore, a volume expansion method and a momentum source expansion method were proposed for calculating the solid volume fraction of the dependent domain and the source term of the influential domain for the coarse particles. Furthermore, the sample point method was adopted to obtain the solid volume fraction in the dependent domain for the fine particles, and the momentum source term was only updated to the particle-located cell. Subsequently, single-particle settling and binary-particle fluidizing numerical experiments were used to verify the calculation accuracy of the model. The investigation can provide a new method for numerical simulation of liquid–solid flow with wide particle size distributions.
The effect of demographic stochasticity on Zika virus transmission dynamics: Probability of disease extinction, sensitivity analysis, and mean first passage time
Authors: Maity Sunil , Sarathi Mandal Partha
Published: March 2024

Viral infections spread by mosquitoes are a growing threat to human health and welfare. Zika virus (ZIKV) is one of them and has become a global worry, particularly for women who are pregnant. To study ZIKV dynamics in the presence of demographic stochasticity, we consider an established ZIKV transmission model that takes into consideration the disease transmission from human to mosquito, mosquito to human, and human to human. In this study, we look at the local stability of the disease-free and endemic equilibriums. By conducting the sensitivity analysis both locally and globally, we assess the effect of the model parameters on the model outcomes. In this work, we use the continuous-time Markov chain (CTMC) process to develop and analyze a stochastic model. The main distinction between deterministic and stochastic models is that, in the absence of any preventive measures such as avoiding travel to infected areas, being careful from mosquito bites, taking precautions to reduce the risk of sexual transmission, and seeking medical care for any acute illness with a rash or fever, the stochastic model shows the possibility of disease extinction in a finite amount of time, unlike the deterministic model shows disease persistence. We found that the numerically estimated disease extinction probability agrees well with the analytical probability obtained from the Galton–Watson branching process approximation. We have discovered that the disease extinction probability is high if the disease emerges from infected mosquitoes rather than infected humans. In the context of the stochastic model, we derive the implicit equation of the mean first passage time, which computes the average amount of time needed for a system to undergo its first state transition.
CanGWhandle multireference systems?
Authors: Ammar Abdallah , Marie Antoine , Rodríguez-Mayorga Mauricio , Burton Hugh G. A. , Loos Pierre-François
Published: March 2024

Due to the infinite summation of bubble diagrams, the GW approximation of Green’s function perturbation theory has proven particularly effective in the weak correlation regime, where this family of Feynman diagrams is important. However, the performance of GW in multireference molecular systems, characterized by strong electron correlation, remains relatively unexplored. In the present study, we investigate the ability of GW to handle closed-shell multireference systems in their singlet ground state by examining four paradigmatic scenarios. First, we analyze a prototypical example of a chemical reaction involving strong correlation: the potential energy curve of BeH2 during the insertion of a beryllium atom into a hydrogen molecule. Second, we compute the electron detachment and attachment energies of a set of molecules that exhibit a variable degree of multireference character at their respective equilibrium geometries: LiF, BeO, BN, C2, B2, and O3. Third, we consider a H6 cluster with a triangular arrangement, which features a notable degree of spin frustration. Finally, the dissociation curve of the HF molecule is studied as an example of single bond breaking. These investigations highlight a nuanced perspective on the performance of GW for strong correlation depending on the level of self-consistency, the choice of initial guess, and the presence of spin-symmetry breaking at the Hartree–Fock level.
Photofragmentation of cyclobutanone at 200 nm: TDDFT vs CASSCF electron diffraction
Authors: Martín Santa Daría Alberto , Hernández-Rodríguez Javier , Ibele Lea M. , Gómez Sandra
Published: March 2024

To simulate a 200 nm photoexcitation in cyclobutanone to the n-3s Rydberg state, classical trajectories were excited from a Wigner distribution to the singlet state manifold based on excitation energies and oscillator strengths. Twelve singlet and 12 triplet states are treated using TD-B3LYP-D3/6-31+G** for the electronic structure, and the nuclei are propagated with the Tully surface hopping method. Using time-dependent density functional theory, we are able to predict the bond cleavage that takes place on the S1 surface as well as the ultrafast deactivation from the Rydberg n-3s state to the nπ*. After showing that triplet states and higher-lying singlet states do not play any crucial role during the early dynamics (i.e., the first 300 fs), the SA(6)-CASSCF(8,11)/aug-cc-pVDZ method is used as an electronic structure and the outcome of the non-adiabatic dynamic simulations is recomputed. Gas-phase ultrafast electron diffraction spectra are computed for both electronic structure methods, showing significantly different results.
Influence of embedded structure on two-phase reactive flow characteristics for a small combustion chamber with a moving boundary
Authors: Wang Yongtao , Zhang Xiaobing
Published: March 2024

In special launch scenarios such as armament and aerospace, the scale of the launch system is severely restricted, which causes unstable combustion of propellant. An embedded structure for the small propulsion system driven by solid propellant is proposed to overcome this problem. This study aims to demonstrate the two-phase flow behaviors and launch safety of the combustion chamber with an embedded structure. A two-dimensional two-phase flow model based on the modified two-fluid theory is developed to describe the detailed two-phase flow behaviors in the combustion chamber during launching. Different from most of the existing studies, the constitutive equations determined from actual physical conditions are used to close the system of continuity equations. The numerical results are compared with that of the experiment to verify the accuracy of the numerical model. On this basis, the launch performance of the embedded structure is investigated. The numerical results indicate that the embedded structure facilitates the ignition process and reduces the risk of excessive pressure, but decreases the muzzle velocity at the same time. In addition, the effect of design parameters on launch safety is further investigated. Design parameters directly affect the launch safety, and the selection of reasonable parameters is a useful method for enhancing the launch performance.
Combined resonant tunneling and rate equation modeling of terahertz quantum cascade lasers
Authors: Chen Zhichao , Liu Andong , Chang Dong , Dhillon Sukhdeep , Razeghi Manijeh , Wang Feihu
Published: March 2024

Terahertz (THz) quantum cascade lasers (QCLs) are technologically important laser sources for the THz range but are complex to model. An efficient extended rate equation model is developed here by incorporating the resonant tunneling mechanism from the density matrix formalism, which permits to simulate THz QCLs with thick carrier injection barriers within the semi-classical formalism. A self-consistent solution is obtained by iteratively solving the Schrödinger–Poisson equation with this transport model. Carrier–light coupling is also included to simulate the current behavior arising from stimulated emission. As a quasi-ab initio model, intermediate parameters, such as pure dephasing time and optical linewidth, are dynamically calculated in the convergence process, and the only fitting parameters are the interface roughness correlation length and height. Good agreement has been achieved by comparing the simulation results of various designs with experiments, and other models such as density matrix Monte Carlo and non-equilibrium Green's function method that, unlike here, require important computational resources. The accuracy, compatibility, and computational efficiency of our model enable many application scenarios, such as design optimization and quantitative insights into THz QCLs. Finally, the source code of the model is also provided in the supplementary material of this article for readers to repeat the results presented here, investigate, and optimize new designs.
Experimental study of interactions between dual porous particles released side by side during settling
Authors: Liu Jieqing , Xiao Yang , Liang Dongfang , Zhang Pei , Zhang Taotao , Wang Zhihao , Liu Jiaming
Published: March 2024

The settling of porous particles is relevant to many fields of research, which is essential for many natural phenomena and industrial processes. However, due to the complex particle–particle and particle–fluid interactions, the mechanism of porous particles settling has not been fully understood yet. In this study, the settling behaviors and interactions of dual porous particles released side by side are experimentally investigated. The Reynolds number varied from 12 to 258, which is within the transition zone. Particle Tracking Velocimetry and Particle Image Velocimetry were utilized to capture the particles' trajectories and velocities and provide insight into the flow fields around the particles, respectively. The influences of particle porosity ɛ, initial spacing between particles l0*, and Reynolds number Re on the settling process are systematically studied. In this study, ɛ varies from 0 to 0.858 and l0* varies from 0 to 5. The experimental results reveal that there was repulsion between porous particles during settling, which was negatively correlated with l0* and ɛ. When ɛ > 0.3 and l0* < 0.5, the magnitude of the repulsion between porous particles is significantly different from that of the solid particles, and thus, the effect of porosity is important. For other cases, the interaction between porous particles is essentially the same as that between solid particles. The repulsion between the two particles is a result of flow fields asymmetry, and this repulsion vanishes when l0* > 5. The settling process can be divided into three stages depending on the repulsion. Compared to solid particles, the interactions between porous particles are weaker. The reason is that the pore reduces the duration of particle interactions in the repulsion phase, which contributes to the particles to rapid approaching to reach the stable phase.
Unraveling the rapid ion migration in perovskite solar cells by circuit-switched transient photoelectric technique
Authors: Wu Ziyou , Yuan Shuai , Miao Shaoshuai , Li Yiyi , Zhang Wenqi , Cao Dandan , Nie Junyu , Wang Yi , Ai Xi-Cheng , Zhang Jian-Ping
Published: March 2024

Ion migration activated by illumination is a critical factor responsible for the performance decline and stability degradation of perovskite solar cells (PSCs). While ion migration has been widely believed to be much slower than charge transport, recent research suggests that, despite the lack of understanding of the mechanism, it may also be involved in a series of rapid photoelectric responses of PSCs. Here, we report an improved circuit-switched transient photoelectric technique with nanosecond temporal resolution, which enables quantitative characterization of ion migration dynamics in PSCs across a fairly broad time window. Specifically, ion migration occurring within microseconds after illumination (corresponding to a diffusion length of ∼10−7 cm) is unambiguously identified. In conjunction with the composition engineering protocol, we justify that it arises from the short-range migration of halide anions and organic cations around the contact/perovskite interface. The rapid ion migration kinetics revealed in this work strongly complement the well-established ion migration model, which offers new insights into the mechanism of ion-carrier interaction in PSC devices.
Performance improvement studies of axially partitioned dual band magnetically insulated line oscillator
Authors: V. Sivavenkateswara Rao
Published: March 2024

In magnetically insulated line oscillator (MILO)s, a proportion of device current is responsible for the self-generated magnetic field that aids electron flow confinement in the anode cathode gap, thereby suitable RF generation. The device currents should not be high due to its direct impact on device efficiency, and electron energy depositions at load can lead to anode plasma formation. Also, the lower currents can facilitate the device to operate at larger voltages and/or for longer operational times. In this article, couple of axially partitioned dual band MILOs (DBMILO) designs that operate at lower device currents in comparison with the existing axially partitioned DBMILOs in the literature is presented. For one design with the radius of the slow wave structure (SWS), i.e., RSWS = 40 mm, the injection of the DC electron beam parameters 505 kV and 49 kA, generated an output RF power of ∼5.8 GW oscillating at 3.71 and 10.16 GHz (S-and X- bands) concurrently with ∼23.8% conversion efficiency. However, the other design (RSWS = 40.6 mm) at beam voltage 505 kV and device current of 47 kA generated an output RF power of >3.85 GW oscillating at 3.5 and 10.5 GHz, concurrently, where the frequencies are harmonically related. Thus, the proposed designs yielded significant device current reduction to ∼47 and ∼49 kA from ∼56 kA (existed), respectively, thereby drop of 16% and 12.5% to its counter designs, respectively. Also, there is substantial reduction in the electron energy depositions, thus the occurrence of anode plasma formations. Moreover, the peak conversion efficiency is enhanced to 23.4% and 16.4%, from 12.8%.
Statistical analysis of the phase space density changes of radiation belt source, seed, and relativistic electrons in response to geomagnetic storms
Authors: Zou Zhengyang , Zuo Pingbing , Ni Binbin , Huang Hanyu , Hu Jiahui , Wei Jiayun , Yuan Qitong , San Wen
Published: March 2024

The radiation belt “source” (a few to tens of keV), “seed” (hundreds of keV), and “relativistic” (>1 MeV) electrons are highly fabricated by geomagnetic storms or substorms. The present study statistically analyzed the phase-space density (PSD) of the radiation belt electrons at the first adiabatic invariant μ = 101–104 MeV/G between L* (the inversion of the third adiabatic invariant) from 2.5 to 5.5 in response to geomagnetic storms. The statistical results indicate that after the storms, more than 25% of the relativistic electron PSD were pumped at L* > ∼3.5, with a peak at approximately L* = 4.0, while approximately 25% of them also showed a clear loss at L* > 3.5. Comparably, the source electrons mainly increased within almost the whole outer radiation belt, and the seed electrons may serve as intermediary populations, in which source and loss processes engage in strong competition. As the dynamic pressure and substorm intensify, the primary “enhancement region” and “loss region” converge near a few 102 MeV/G. Furthermore, analysis that the magnetopause shadowing effect mainly contributed to the observed losses one day after the main phase, while the substorm-injected particles and the seceded acceleration processes likely accounted for the observed increase in the electron PSD three days after the main phase. The present study provides a new and comprehensive insight into the statistical understanding of the change rates of the electron PSD and the competition between source and loss processes in response to geomagnetic storms.
Ethyl-Iophenoxic acid as a serum marker for oral baiting of Tasmanian devils
Authors: Pye Ruth , Nichols David , Nofs Sally A. , Gilbert Amy T. , Flies Andrew S.
Published: March 2024

Oral baits containing vaccines, medicants or toxicants have been delivered to a broad range of wildlife species to protect against or treat disease, or suppress populations. Ethyl-Iophenoxic acid (Et-IPA) is used as a biomarker to determine oral bait consumption by wildlife species to assess and refine baiting strategies. Et-IPA is a persistent biomarker in many eutherian mammal species but not in the two marsupial species, swamp wallaby (Wallabia bicolor) and brushtail possum (Trichosurus vulpecula), tested to date. Et-IPA has not previously been evaluated in carnivorous marsupials. The Tasmanian devil (Sarcophilus harrisii), the largest extant carnivorous marsupial, is threatened by devil facial tumour disease (DFTD). Development of an oral DFTD vaccine bait is underway. In this study, eight devils were fed between 1 mg and 50 mg Et-IPA via oral baits to assess the effectiveness of Et-IPA as a serum biomarker for this species. Using liquid chromatography with tandem mass spectrometry, serum Et-IPA was detected in the devils up to 206 days after ingestion. This study demonstrates the utility of Et-IPA for estimating oral bait consumption by devils, the first carnivorous marsupial species to which this applies.
Heterogeneous elasticity drives ripening and controls bursting kinetics of transcriptional condensates
Authors: Meng Lingyu , Mao Sheng , Lin Jie
Published: March 2024

Many biomolecular condensates, including transcriptional condensates, are formed in elastic mediums. In this work, we study the nonequilibrium condensate dynamics in a chromatin-like environment modeled as a heterogeneous elastic medium. We demonstrate that the ripening process in such an elastic medium exhibits a temporal power-law scaling of the average condensate radius, depending on the local stiffness distribution and different from Ostwald ripening. Moreover, we incorporate an active process to model the dissolution of transcriptional condensates upon RNA accumulation. Intriguingly, three types of kinetics of condensate growth emerge, corresponding to constitutively expressed, transcriptional-bursting, and silenced genes. Furthermore, the simulated burst frequency decreases exponentially with the local stiffness, through which we infer a lognormal distribution of local stiffness in living cells using the transcriptome-wide distribution of burst frequency. Under the inferred stiffness distribution, the simulated distributions of bursting kinetic parameters agree reasonably well with the experimental data. Our findings reveal the interplay between biomolecular condensates and elastic mediums, yielding far-reaching implications for gene expression.
Comparison of liquid density measurements among SIM NMIs - SIM.M.D-S7
Authors: Santiago Luis Omar Becerra , Preste Sheila , Peña Perez Luis Manuel
Published: March 2024

Main text

The aim of this comparison was to compare measurement results on liquid density at 20°C and at atmospheric pressure among National Metrology Institutes (NMIs) belonging to the Inter-American Metrology System (SIM, by its acronym in Spanish).

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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Final report on EURAMET key comparison EURAMET.M.D-K2.2 (1523)
Authors: Prochaska L , Rauch J , Furtado A , Benga F , Bartos P , Bebic J , Lenard E , Alisic S , Alic A , Neuvonen P T , Sariyerli G S , Akcadag Ü Y , Ciubara A , Bescupschii A
Published: March 2024

Main text

The key comparison EURAMET.M.D-K2.2 (1523)on the density of liquids determined by oscillation type density meters was organized and carried out within the framework of the EMPIR project 17RPT02 "rhoLiq". Density measurements of liquids are mainly performed by laboratories calibrating or checking liquid density measuring instruments such as oscillation-type density meters. Another aim of this comparison was to establish traceability for liquid density measurements at emerging National Metrology Institutes (NMIs) to enable them to provide high-level measurement and calibration services for national stakeholders, e.g. food, chemical, pharmaceutical and petroleum industries. The results of this comparison can be used to claim calibration and measurement capabilities (CMCs).

Most European emerging NMIs in this project had not yet participated in comparisons or obtained unsatisfactory results, or the uncertainty had an unfit magnitude for purpose.

BEV (Austria) piloted this comparison, supported by PTB (Germany).

Samples of deuterated water, tetrachloroethylene and oil of high viscosity were measured in the temperature range from 5 °C to 20 °C at atmospheric pressure by hydrostatic weighing for this comparison.

The coronavirus pandemic caused delays in the proposed initial schedule of this key comparison. Measurements were performed in 2021. The reference values of the key comparison were linked to CCM.D-K2 for PTB and EURAMET.M.D-K2 for BEV.

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 CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Benchmark calculations for anisotropic scattering in kinetic models for low temperature plasma
Authors: Flynn M , Vialetto L , Fierro A , Neuber A , Stephens J
Published: March 2024

Benchmark calculations are reported for anisotropic scattering in Boltzmann equation solvers and Monte Carlo collisional models of electron swarms in gases. The work focuses on isotropic, forward, and screened Coulomb models for angular scattering in electron-neutral collisions. The impact of scattering on electron swarm parameters is demonstrated in both conservative and non-conservative model atoms. The practical implementation of anisotropic scattering in the kinetic models is discussed.
An omnidirectional spatial monocular visual localization and tracking method for indoor unmanned aerial vehicles based on the two-axis rotary table
Authors: Wu Jun , Wang Haoshuang , Shan Tengfei , Guo Runxia , Chen Jiusheng
Published: March 2024

Aiming at the complexity and poor adaptability of the calibration process in the traditional unmanned aerial vehicles (UAV) indoor visual positioning, this paper proposes an omnidirectional spatial tracking and localization method for indoor UAV based on the two-axis rotary table. Firstly, the position of the UAV fuselage feature points in the camera coordinate system of the turntable camera is computed by the Pespective-n-Point algorithm utilizing known position information of a plurality of feature points with pixel coordinate information in the corresponding image. Pixel coordinate information is extracted by obtaining UAV body-specific feature points from rotary table camera shots. Then, UAV localization in omnidirectional space can be obtained by using the calibrated rotary axis parameters of the rotary table and the rotation angle of the rotary table and substituting them into Rodriguez’s formula to unify the UAV position information acquired by the rotary table camera at different positions into a unified coordinate system. Finally, the angle at which the rotary table should rotate is calculated from the obtained UAV pose and the spatial position of the camera optical center and the rotary axis of the rotary table. The calculated angle is fed back to the turntable as feedback information. The rotary table receiving the feedback information is rotated to a position where the UAV is located at the center of the camera image. Thereby the tracking and localization of the UAV is realized. The experimental results show that the spatial range of localization is greatly expanded with the localization accuracy reaching the level of binocular visual localization. The omnidirectional spatial tracking and localization of indoor UAV can be conveniently realized by this method.
The optimal algorithm for eliminating nonlinear error in phase measurement profilometry based on global statistical phase feature function
Authors: Zhu Zhenmin , Xu Xiaokai , Long Wenqing , He Lifa , Zhang Jing , Liu Haoran , Jiang Jianru
Published: March 2024

In a digital fringe projection structured light system, the nonlinear phase error is generated by the gamma effect of both the projector, camera, and other electronic devices. One of the existing nonlinear correction methods is active correction by projecting ideal fringes as far as possible, and the other is passive compensation after capturing aberrant fringes. The former has higher accuracy but needs to capture a large number of fringe patterns, while the latter does not need many fringe patterns, but is not only greatly affected by random noise and out-of-focus effects, but also has poor accuracy. In this paper, an optimal algorithm for eliminating nonlinear error based on global statistical phase feature function (GSPF) is proposed. The phase distribution can be estimated from the difference between the global cumulative distribution function (CDF) and the normalized (CDF). For an ideal fringe pattern without nonlinear error and a fringe pattern with nonlinear error, the region wrapped by the x-axis normalized CDF is much smaller than the region wrapped by the x-axis global CDF, and the larger the nonlinear error is, the larger the difference between the two is. Therefore, the GSPF can be used for nonlinear error correction. Then the optimal nonlinear error correction is performed based on the minimum difference between the compensated phase entropy and the ideal phase entropy. The method does not require too many steps of phase-shifting, and only three fringe patterns are needed to realize accurate and robust correction. Experimental results show that the method is fast, highly accurate and robust. Using this technique, high accuracy measurements can be achieved with the traditional three-step phase-shifting algorithm.
Numerical study on how advection delays and removes singularity formation in the Navier–Stokes equations
Authors: Ohkitani Koji
Published: March 2024

We numerically study a distorted version of the Euler and Navier–Stokes equations, which are obtained by depleting the advection term systematically. It is known that in the inviscid case some solutions blow up in finite time when advection is totally discarded, Constantin (1986 Commun. Math. Phys.
104 311–26). Taking a pair of orthogonally offset vortex tubes and the Taylor–Green vortex as initial data, we show the following. (1) Blowup persists even with viscosity when advection is discarded, and (2) for small viscosity, the time of blowup increases logarithmically as we reinstate advection using a continuous parameter, which would be consistent with the regularity of the Navier–Stokes equations. A tiny mismatch in the coefficient of the advection term, as minute as parts per trillion, throws the system out of compactness and leads to blowup.
Generating spokes in direct current magnetron sputtering discharges by an azimuthal strong-to-weak magnetic field strength transition
Authors: Rudolph Martin , Diyatmika Wahyu , Rattunde Oliver , Schuengel Edmund , Kalanov Dmitry , Patscheider Jörg , Anders André
Published: March 2024

Spokes are regions of enhanced ionization in magnetron sputtering discharges that are interesting because of their role for magnetron operation and their potential effect on deposition processes. Here, we show that spokes can intentionally be generated by introducing a strong-to-weak magnetic field strength transition along the racetrack. Spokes are triggered at the transition point from an accelerating electron drift when weakening the magnetic field strength. The spokes are then propagating against the electron drift into the strong magnetic field strength section of the racetrack. At the weak-to-strong magnetic field transition, we observe the inverse effect. The electron drift is decelerated at this point, creating a region of enhanced optical emission. From rectangular racetracks this is known as the cross-corner effect. Here, we show that a corner is not necessary for observing that effect. Pronounced spokes at low working gas pressure of 0.2 Pa exhibit a substructure that could be caused by the diocotron instability previously predicted by computer simulations.
Two-photon coherence in a DROP-FWM medium
Authors: Shukla Vinay , Ray Ayan
Published: March 2024

In this work, we report experimental studies on coherence in a medium exhibiting DROP (Double Resonance Optical Pumping)-FWM (Four Wave Mixing). Here 5S1/2(F) → 5P3/2(F/) → 5D (F//) two photon transition of hot 87Rb atoms is used. The 5S→5P connection is modified by introducing an additional beam phase coupled to the original beam linking F = 2 → F/ transition. The frequency of the additional beam is offset from that of the original beam by ≈ +10Γ (Γ is natural linewidth). Such a two-beam configuration in F→F/ manifold effectively satisfies conditions of Vee (V) linkage or degenerate two-level connection (DTLC), depending on the detuning of the 780nm laser. This transformation profoundly affects the behavior of the ensuing Ladder (Ξ) system. While the (I) Ξ +V condition is favorable for Electromagnetically Induced Transparency (EIT), the (ii) Ξ + DTLC brings in the effect of Electromagnetically Induced Absorption (EIA). The EIT-dominated situation is helpful for FWM to take place, and the EIA effect augments the stronger presence of DROP. This condition is verified by monitoring the blue fluorescence emanating from the 5D→6P3/2→5S1/2 decay route. The DROP effect follows the Amplified Spontaneous Emission (ASE) pattern in the media. The origin of blue photons is also due to FWM under EIT conditions. In the case of EIA, the dominant condition increment in blue fluorescence is due to increased stimulated emission. The blue photons mainly contributed by (i) FWM and (ii) increased participation of stimulated emission are directional in nature and phase coherent.