bluuebunny/crossref_metadata_2025 huggingface dataset:
Lower Uterine Segment Corrugated Sutures in Hemorrhage during
Cesarean Section because Previal and/or Placenta Accreta Spectrum: Case Reports
Series and Literature Review
Authors: Habek Dubravko , Mikuš Mislav , Cerovac Anis
Published: June 2024

Objectives We present the original technique of compression hemostatic
sutures on the lower uterine segment due to early postpartum hemorrhage during
cesarean section, with a literature review.

Methods A retrospective clinical case study was conducted at the tertiary
perinatal center. Twelve patients had nine planned and three urgent cesarean
sections due to antenatally verified placenta previa and/or placenta accreta
spectrum and defined early postpartum hemorrhage > 1000 mL during cesarean
section. As the use of uterotonics failed to produce any effect and hemorrhage
persisted, compression sutures of the lower uterine segment were made by our own
technique, as follows: below the hysterotomy, a horizontal corrugated suture is
placed from the right to the left corner and after 2–3 cm vertically and
backwards at several sites from the left to the right corner, where it is
tightened.

Results Seven patients had one cesarean section, three patients had two
cesarean sections, and seven patients had pregnancy from the in vitro
fertilization procedure in their history. There were six patients with placenta
previa and six patients with anterior invasive placenta accreta or increta.
Original hemostatic procedure was applied successfully in ten cases, and after
placement of O'Leary suture and persistent bleeding in two cases. In this
group, no hysterectomy was performed, and patients received blood transfusion of
440–880 mL. Three patients later had spontaneous pregnancies.

Conclusion Our own hemostatic method with a simple technique, fast
learning, and minimal logistics contributes to successful management of this
currently global problem of morbidly adherent placenta previa.
Minimal Learning Curve for Minimally Invasive Aortic Valve Replacement
Authors: Leviner Dror B. , Ronai Tom , Abraham Dana , Eliad Hadar , Schwartz Naama , Sharoni Erez
Published: June 2024

Background Minimally invasive aortic valve replacement (MiAVR) is an established technique for surgical aortic valve replacement (AVR). Although MiAVR was first described in 1993 and has shown good results compared with full sternotomy AVR (FSAVR) only a minority of patients undergo MiAVR. We recently started using MiAVR via an upper hemisternotomy. We aimed to examine the early results of our initial experience with this technique.

Methods We compared 55 MiAVR patients with a historical cohort of 142 isolated FSAVR patients (December 2016–December 2022). The primary outcome was in-hospital mortality. Secondary outcomes included cardiopulmonary bypass (CPB) and cross-clamp times, blood product intake, in-hospital morbidity, and length of intensive care unit and hospital stay.

Results There was no significant difference in preoperative characteristics, including age, laboratory values, and comorbidities. There was no significant difference between the groups regarding in-hospital mortality (FSAVR 3.52 vs. MiAVR 1.82%). There was no significant difference in CPB time (FSAVR 103.5 [interquartile range: 82–119.5] vs. MiAVR 107 min [92.5–120]), aortic cross-clamp time (FSAVR 81 [66–92] vs. MiAVR 90 min [73–99]), and valve size (FSAVR 23 [21–25] vs. MiAVR 23 [21–25]). The incidence of intraoperative blood products transfusion was significantly lower in the MiAVR group (10.91%) compared with the FSAVR group (25.35%, p = 0.03).

Conclusion Our findings further establish the possibility of reducing invasiveness of AVR without compromising patient safety and clinical outcomes. This is true even in the learning curve period and without requiring any significant change in the operative technique and dedicated equipment.
Recyclable Palladium-Catalyzed Carbonylative Coupling of Aryl Halides and Organoaluminum Compounds with tert-Butyl Iso­cyanide as CO Equivalent Leading to 1,2-Diketones
Authors: You Shengyong , Cai Mingzhong , Tu Zhiyuan , Zhan Jianan
Published: June 2024

An efficient heterogeneous palladium-catalyzed carbonylative coupling of aryl halides and organoaluminum compounds has been developed using tert-butyl isocyanide as CO equivalent. The carbonylation reaction proceeds smoothly in toluene with KOtBu as a base at 100 °C by using 10 mol% of an SBA-15-anchored bidentate phosphine palladium(0) complex [2P-SBA-15-Pd(0)] as the catalyst and provides a general and practical approach for the assembly of 1,2-diketones in good to excellent yields. This heterogenized palladium catalyst can be readily separated and recovered via a simple centrifugation process and reused for more than seven cycles with almost consistent catalytic efficiency.
Subluxação intrabainha dos tendões fibulares: Relato de três casos com nota técnica
Authors: Lima Cunha Raquel , Castro Alexandre , Atilano Carvalho Pedro , Gomes Marta , Miranda António , Teixeira João
Published: June 2024

A instabilidade intrabainha fibular provoca dor com estalo e clique audível na lateral do tornozelo. Esta doença é pouco relatada e sua incidência exata é desconhecida. Consiste em uma subluxação retromaleolar transitória dos tendões fibulares com movimento anormal dos tendões fibulares entre si e integridade do retináculo fibular superior. O diagnóstico requer alta suspeita clínica e a ultrassonografia dinâmica é o melhor estudo de imagem para avaliação da instabilidade fibular quando o retináculo fibular superior está intacto para detecção de instabilidade intrabainha fibular. O objetivo do presente estudo é descrever como chegar ao diagnóstico e relatar e avaliar a técnica cirúrgica para o tratamento desta doença. Neste relato, descrevemos três casos da doença que foram submetidos ao tratamento cirúrgico com sucesso com procedimento de aprofundamento do sulco fibular e retinuloplastia do retináculo superior. Esta técnica cirúrgica proporciona bons resultados em caso de falha do tratamento conservador.
Europeanisation in the aftermath of COVID-19: the organisational adaptation of the central governance of the National Recovery and Resilience Plan in Italy
Authors: Bressanelli Edoardo , Natali David
Published: June 2024

While much of the recent literature on the impact of COVID-19 has focussed on governance at the EU level and specific policy areas, the changing political institutional arrangements within the EU Member States themselves have received significantly less attention. This article aims to contribute filling this gap by asking: how, and to what extent, has the core executive in Italy changed to manage and implement the National Recovery and Resilience Plan (NRRP)? Italy has been heavily hit by the COVID-19 pandemic and has subsequently been allocated the largest proportion of the Next Generation EU (NGEU) funds: it is therefore a ‘most likely’ case of organisational adaptation. We argue that the implementation of the NRRP triggers centralisation of power in the core executive. Such concentration of power, however, takes different forms depending on the composition of the executive. We also find that ‘coordinative’ Europeanisation occurs through the continuous interaction and exchange between the executive actors (political and administrative) based in Rome and the European Commission in Brussels. Such interaction showcases the attempt to manage both further integration and politicisation of the EU. The collaboration between the European Commission and the national executive is based both on the recognition of the value of the political ownership of the NRRP and the importance of the EU support for post-pandemic recovery.
Transverse modulational dynamics of quenched patterns
Authors: Dunn Sierra , Goh Ryan , Krewson Benjamin
Published: June 2024

We study the modulational dynamics of striped patterns formed in the wake of a planar directional quench. Such quenches, which move across a medium and nucleate pattern-forming instabilities in their wake, have been shown in numerous applications to control and select the wavenumber and orientation of striped phases. In the context of the prototypical complex Ginzburg–Landau and Swift–Hohenberg equations, we use a multiple-scale analysis to derive a one-dimensional viscous Burgers’ equation, which describes the long-wavelength modulational and defect dynamics in the direction transverse to the quenching motion, that is, along the quenching line. We show that the wavenumber selecting properties of the quench determine the nonlinear flux parameter in the Burgers’ modulation equation, while the viscosity parameter of the Burgers’ equation is naturally determined by the transverse diffusivity of the pure stripe state. We use this approximation to accurately characterize the transverse dynamics of several types of defects formed in the wake, including grain boundaries and phase-slips.
Flow cytometer for a dilution-free measurement approach with sample recollection
Authors: Hein Y. , Zipfel F. , O’Connor G. , Macdonald R. , Hussels M.
Published: June 2024

Blood testing using flow cytometry is a common and rapid method for the initial screening and diagnosis of patients. Measurements are often combined with other scientific techniques, and analyzed samples are commonly diluted and discarded afterward. When the sample is recollected instead, sample dilution is a challenge when the sample is intended or needed for additional measurements. Therefore, it is advantageous to recollect the undiluted sample. In order to enable measurements of the same undiluted sample aliquot, we designed and constructed a purpose-built flow cytometer. Our instrument employs syringes, acoustic focusing, and an open fluidics system to recollect and reuse the unadulterated sample. The cytometer is compact, which reduces sample consumption. It acquires forward, sideward, and fluorescence signals, offering opportunities for diverse measurement approaches. In particular, our cytometer has been designed to be ready for additional downstream analysis of cells, e.g., applying mass spectrometry, magnetic resonance spectroscopy, or other analytical tools. This study presents results on instrument performance, a comparison with a cytometer that uses standard hydrodynamic focusing, and a proof of concept for multiple measurements.
Experimental investigation of the chaotification of a Duffing-like electronic oscillator under two-frequency excitation
Authors: da Silva Josiane C. , Gusso A. , Dantas W. G. , Ujevic Sebastian
Published: June 2024

Two-frequency excitation has recently emerged as an efficient method to generate strong chaotification of Duffing and Duffing-like dynamical systems with both single- and double-well potentials. For the systems with a double-well potential, large continuous regions with robust chaos (chaotic attractor insensitive to changes in the system parameters) have been predicted to exist when the method is applied. Motivated by these theoretical results, in this work, we investigate experimentally the chaotification under two-frequency excitation of a simple electronic circuit analogous to the double-well Duffing oscillator. The experimental results confirm the theoretical expectations, and a strong chaotification is observed. Evidences are also presented that the chaotic attractor is robust. Therefore, the work establishes experimentally the two-frequency excitation as a simple and reliable method of chaotification. Furthermore, because of its ease of fabrication, the experimental results turn the particular circuit considered in this work into an interesting practical alternative as a reliable source of continuous-time chaotic signals.
Dual-luminophore pressure-sensitive paint measurement using three-gate lifetime method with photodegradation correction
Authors: Uchida Kazuki , Nakakita Kazuyuki , Sugioka Yosuke , Asai Keisuke , Nonomura Taku
Published: June 2024

In this paper, we propose a photodegradation correction method for the dual-luminophore pressure-sensitive paint (PSP) measurement using lifetime-based imaging, which was proposed for correction of the temperature-induced error but has suffered from photodegradation in the previous studies. We introduced a parameter that characterizes the photodegradation of a dual-luminophore PSP as the intensity ratio between the two luminophores. The changes in the calibration coefficients for the pressure and the temperature due to photodegradation were corrected based on this parameter. In this study, a coupon-based calibration test was performed, and the luminescence characteristics of the dual-luminophore PSP including photodegradation were investigated. Then, the proposed method was applied to a coupon-based validation test and a jet impingement test, and the effectiveness of the method was evaluated by comparing results with and without correction. The pressure measurement accuracy was significantly improved by photodegradation correction.
Design, development, and performance of a versatile graphene epitaxy system for the growth of epitaxial graphene on SiC
Authors: Mondal S. , Jayalekshmi U. J. , Singh S. , Mukherjee R. K. , Shukla A. K.
Published: June 2024

A versatile graphene epitaxy (GrapE) furnace has been designed and fabricated for the growth of epitaxial graphene (EG) on silicon carbide (SiC) in diverse growth environments ranging from high vacuum to atmospheric argon pressure. Radio-frequency induction enables heating capabilities up to 2000 °C, with controlled heating ramp rates achievable up to 200 °C/s. The details of critical design aspects and temperature characteristics of the GrapE system are discussed. The GrapE system, being automated, has enabled the growth of high-quality EG monolayers and turbostratic EG on SiC using diverse methodologies, such as confinement-controlled sublimation (CCS), open configuration, polymer-assisted CCS, and rapid thermal annealing. This showcases the versatility of the GrapE system in EG growth. Comprehensive characterizations involving atomic force microscopy, Raman spectroscopy, and low-energy electron diffraction techniques were employed to validate the quality of the produced EG.
Taxis-driven complex patterns of a plankton model
Authors: Chen Mengxin , Ham Seokjun , Kim Junseok
Published: June 2024

This paper reports an important conclusion that self-diffusion is not a necessary condition for inducing Turing patterns, while taxis could establish complex pattern phenomena. We investigate pattern formation in a zooplankton–phytoplankton model incorporating phytoplankton-taxis, where phytoplankton-taxis describes the zooplankton that tends to move toward the high-densities region of the phytoplankton population. By using the phytoplankton-taxis sensitivity coefficient as the Turing instability threshold, one shows that the model exhibits Turing instability only when repulsive phytoplankton-taxis is added into the system, while the attractive-type phytoplankton-taxis cannot induce Turing instability of the system. In addition, the system does not exhibit Turing instability when the phytoplankton-taxis disappears. Numerically, we display the complex patterns in 1D, 2D domains and on spherical and zebra surfaces, respectively. In summary, our results indicate that the phytoplankton-taxis plays a pivotal role in giving rise to the Turing pattern formation of the model. Additionally, these theoretical and numerical results contribute to our understanding of the complex interaction dynamics between zooplankton and phytoplankton populations.
Halide perovskite x-ray detectors: Fundamentals, progress, and outlook
Authors: Liu Runkai , Li Feng , Zeng Fang , Zhao Rubin , Zheng Rongkun
Published: June 2024

Halide perovskites have demonstrated great potential in x-ray detectors, due to their high x-ray attenuation coefficient, large bulk resistance, ultralong carrier diffusion length, and adjustable bandgap. Moreover, their abundant raw materials and simple processing combined with excellent compatibility with integrated circuits make them ideal for cost-efficient and high-efficiency real-world imaging applications. Herein, we comprehensively reviewed advances and progress in x-ray detection devices based on halide perovskites. We expound on the fundamental mechanisms of interactions between x rays and matter as background and indicate different parameters for different types of x-ray detectors, which guides the basic requirements on how to select and design suitable materials for active layers. After emphasizing the superb properties of halide perovskites through the shortcomings of commercial materials, we evaluate the latest advancements and ongoing progress in halide perovskites with different dimensions and structures for both direct and indirect x-ray detectors, and discuss the effect of dimensional varieties on the device performance. We also highlight current challenges in the area of perovskite x-ray detectors and propose corresponding solutions to optimize halide perovskites and optimize x-ray detectors for next-generation imaging applications.
A moment-based Kalman filtering approach for estimation in ensemble systems
Authors: de Lima André Luiz P. , Li Jr-Shin
Published: June 2024

A persistent challenge in tasks involving large-scale dynamical systems, such as state estimation and error reduction, revolves around processing the collected measurements. Frequently, these data suffer from the curse of dimensionality, leading to increased computational demands in data processing methodologies. Recent scholarly investigations have underscored the utility of delineating collective states and dynamics via moment-based representations. These representations serve as a form of sufficient statistics for encapsulating collective characteristics, while simultaneously permitting the retrieval of individual data points. In this paper, we reshape the Kalman filter methodology, aiming its application in the moment domain of an ensemble system and developing the basis for moment ensemble noise filtering. The moment system is defined with respect to the normalized Legendre polynomials, and it is shown that its orthogonal basis structure introduces unique benefits for the application of Kalman filter for both i.i.d. and universal Gaussian disturbances. The proposed method thrives from the reduction in problem dimension, which is unbounded within the state-space representation, and can achieve significantly smaller values when converted to the truncated moment-space. Furthermore, the robustness of moment data toward outliers and localized inaccuracies is an additional positive aspect of this approach. The methodology is applied for an ensemble of harmonic oscillators and units following aircraft dynamics, with results showcasing a reduction in both cumulative absolute error and covariance with reduced calculation cost due to the realization of operations within the moment framework conceived.
Observation of the early stages of environmental contamination in graphene by friction force
Authors: Almeida Clara M. , Ptak Felipe , Prioli Rodrigo
Published: June 2024

Exposure to ambient air contaminates the surface of graphene sheets. Contamination may arise from different sources, and its nature alters the frictional behavior of the material. These changes in friction enable the observation of the early stages of contaminants’ adsorption in graphene. Using a friction force microscope, we show that molecular adsorption initiates at the edges and mechanical defects in the monolayer. Once the monolayer is covered, the contaminants spread over the additional graphene layers. With this method, we estimate the contamination kinetics. In monolayer graphene, the surface area covered with adsorbed molecules increases with time of air exposure at a rate of 10−14 m2/s, while in bilayer graphene, it is one order of magnitude smaller. Finally, as the contaminants cover the additional graphene layers, friction no longer has a difference concerning the number of graphene layers.
Chiral and directional optical emission from a dipole source coupled to a helical plasmonic antenna
Authors: Kuen Lilli , Löffler Lorenz , Tsarapkin Aleksei , Zschiedrich Lin , Feichtner Thorsten , Burger Sven , Höflich Katja
Published: June 2024

Plasmonic antennas with helical geometry can convert linearly polarized dipole radiation into purely circularly polarized far-fields, and vice versa. Besides large Purcell enhancements, they possess a wide tunability due to the geometry dependence of their resonant modes. Here, the coupling of a dipole emitter embedded in a thin film to plasmonic single and double helices is numerically studied. Using a higher-order finite element method (FEM), the wavelength dependent Purcell enhancement of a dipole with different positions and orientations is calculated and the far-fields with respect to their chirality and radiation patterns are analyzed. Both single and double helices demonstrate highly directional and circularly polarized far-fields for resonant excitation but with significantly improved directional radiation for the case of double helices.
Temperature-driven spin reorientation transition in van der Waals Cr1.7Te2 ferromagnet
Authors: Wang Shasha , Wang Zhou , Jiang Jialiang , Zhang Ying , Li Ruimin , Feng Yan , Liu Ping , Lu Yalin , Sheng Zhigao , Du Haifeng , Gao Nan , Xiang Bin
Published: June 2024

The phenomenon of spin reorientation transition in magnetic materials is truly captivating, as it involves a fascinating change in the direction of magnetic moments. However, the research on spin reorientation transition in two-dimensional (2D) magnetic materials has received limited attention, thus hindering its immense potential for significant advancements in various device applications. In this study, we present a discovery of a spin reorientation transition from an in-plane to an out-of-plane direction in the van der Waals ferromagnet Cr1.7Te2 (Tc = 300 K). This transition occurs at 70 K when the temperature ranges from 3 to 300 K, which is evidenced by the temperature-dependent Hall effect and magnetic anisotropy energy measurements. Notably, the anisotropic evolution observed reveals that the shape anisotropy effect surpasses the magnetocrystalline anisotropy in van der Waals ferromagnet at low temperatures, which is distinct from reported ferromagnetic materials. Furthermore, temperature-dependent x-ray diffraction characterizations confirm that no structural phase transition occurs during this intriguing spin reorientation transition process. These findings establish a strong and solid foundation, offering a promising platform for the design and development of cutting-edge 2D spintronic devices.
Quantitative Raman and x-ray photoelectron spectroscopy of mixed-phase indium selenide films
Authors: Voigt Cooper A. , Tian Mengkun , Peacock Ryan , Wagner Brent K. , Vogel Eric M.
Published: June 2024

Indium selenide is a polymorphous material system that has attracted considerable attention due to the outstanding electronic, optical, ferroelectric, and antiferroelectric properties of its various crystalline phases; however, this polymorphism adds a layer of complexity to the analysis of Raman and x-ray photoelectron (XPS) data of these materials. In this report, a method of quantitative analysis of combined Raman and XPS data is developed to determine the stoichiometry of indium selenide thin films, as well as the phase fraction of β-In2Se3, γ-In2Se3, and κ-In2Se3 within the films. A 13:1 ratio of the indium to selenium sensitivity factors (σIn/σSe = 13) was found to yield the most accurate stoichiometry results. Further structural characterization of the κ-In2Se3 film was performed and points to its existence in these films as a distinct phase, rather than strained γ-In2Se3.
Development of a non-intercepting weak beam current measurement electronics for Heavy Ion Accelerator Facility in Lanzhou
Authors: Wei Yuan , Wu Junxia , Li Zhixue , Zhu Guangyu , Ni Fafu , Du Ze , Su Jianjun , Gu Kewei , Wang Tian , Zhang Yong , Xie Hongming , Li Lili , Jing Long , Qiu Xiaoxuan , Lu Shangshang , Tian Ruixia , Yin Jia , He Peilin
Published: June 2024

Non-destructive measurements of low-intensity charged particle beams are particularly challenging for beam diagnostics. At the Heavy Ion Accelerator Facility in Lanzhou (HIRFL), beams with weak currents below 1 µA are often provided for experiments. The detection of such low beam current is below the threshold of typical standard beam current transformers. Therefore, a low-intensity monitoring system is developed by using a sensitive capacitive pick-up (PU) and low-noise electronics. This device measures beam currents by digitally analyzing the amplitude of the PU signals using a homodyne detection scheme. During lab tests, the amplitude nonlinearity is <0.5% in the operational range of 1 nA–45 µA and the amplitude resolution is 0.94 nA. At present, four measurement systems for low beam currents are installed at HIRFL for the monitoring of standard operating conditions with low beam currents below 1 µA. After an absolute calibration with a Faraday cup, it can be used for accurate beam intensity measurement with a current resolution of about 1 nA.
Hybrid interfacial cryosoret nano-engineering in photonic resonator interferometric scattering microscopy: Insights from nanoparticles and nano-assemblies
Authors: Liu Leyang , Bhaskar Seemesh , Cunningham Brian T.
Published: June 2024

The requirements of augmented signal contrast provided by nanoparticle tags in biosensor microscopy-based point-of-care technologies for cancer and infectious disease diagnostics can be addressed through metallo-dielectric nanoarchitectures that enhance optical scattering and absorption to provide digital resolution detection of single tags with simple instrumentation. Photonic Resonator Interferometric Scattering Microscopy (PRISM) enables label-free visualization of nanometer-scale analytes such as extracellular vesicles and virions, and its applicability can be extended to biomolecular analyte counting through nanoparticle tags. Here, we present template-free, linker-less cryosoret nano-assemblies fabricated via adiabatic cooling (−196 °C) as plasmonic nano-antennas that provide high scattering contrast in PRISM. Plasmonic Ag and Au nanomaterials and their cryosorets are evaluated through imaging experiments and simulations based on the finite element method to understand the photo-plasmonic coupling effect at the surface of a photonic crystal (PC) interface. The Ag and Au cryosorets provide at most 8.29-fold and 6.77-fold higher signal contrast compared to their singlet counterpart. Through the simulations, the averaged field magnitude enhancements of 2.77-fold and 3.68-fold are observed for Ag and Au cryosorets when interfacing with PCs compared to bare glass substrates. The hybrid coupling between the localized Mie and delocalized Bragg plasmons of cryosorets and the underlying PC's guided mode resonance provides insights for developing nano-assembly-based nano-tags for biosensing applications.
Role of Griffiths phase on magnetocaloric properties and critical behavior of half-doped manganites [La0.5Sr0.5−xCaxMnO3(x = 0, 0.25, 0.5)]
Authors: Mandal Sibasish , Mohanty Sipun , Chakravarty Sujay , Mukherjee Samrat
Published: June 2024

In this article, a comprehensive study of the effect of calcium substitution on structural magnetic, magnetocaloric properties, and role of Griffiths phase on magnetocaloric properties of half-doped manganites La0.5Sr0.5−xCaxMnO3(x=0,0.25,0.5)] have been presented. A structural phase transition I4/mcm − Pbnm is observed in the whole series. The system exhibits two magnetic transitions for Ca-00 and Ca-25, whereas only one phase transition is observed for Ca-50. Paramagnetic (PM)–ferromagnetic (FM) transition is observed in the whole series and ferromagnetic (FM) - antiferromagnetic (AFM) phase transition is only observed in Ca-25. Interestingly, short range FM clusters exist in the PM matrix of Ca-50, which is a signature of Griffiths phase (GP). The confirmation of GP has been carried out by performing iso-field magnetization measurements at 200 Oe, 500 Oe, and 1 kOe, respectively. Further magnetocaloric properties have been discussed on the basis of isothermal magnetization curves recorded at certain temperature intervals. Calcium substitution favors the enhancement of magnetic entropy change in the series, especially for Ca-50, a magnetic entropy change of 4.5 J/(kg K) with relative cooling power of 180 J/kg under 5 T magnetic field was observed. Iso-field magnetization and magnetocaloric effect along with critical behavior analysis have been carried out to probe the GP and other inhomogeneities present in the respective series.
The effects of high-pressure annealing on magnetostructural transitions and magnetoresponsive properties in stoichiometric MnCoGe
Authors: Poudel Chhetri Tej , Chen Jing-Han , Young David P. , Dubenko Igor , Talapatra Saikat , Ali Naushad , Stadler Shane
Published: June 2024

In this study, phase transitions (structural and magnetic) and associated magnetocaloric properties of stoichiometric MnCoGe have been investigated as a function of annealing pressure. Metastable phases were generated by annealing at 800 °C followed by rapid cooling under pressures up to 6.0 GPa. The x-ray diffraction results reveal that the crystal cell volume of the metastable phases continuously decreases with increasing thermal processing pressure, leading to a decrease in the structural transition temperature. The magnetic and structural transitions merge and form a first-order magnetostructural transition between the ferromagnetic orthorhombic and paramagnetic hexagonal phases over a broad temperature range (>80 K) spanning room temperature, yielding considerable magnetic entropy changes. These findings demonstrate the utility of thermal processing under high pressure, i.e., high-pressure annealing, to control the magnetostructural transitions and associated magnetocaloric properties of MnCoGe without altering its chemical composition.
Learning QM/MM potential using equivariant multiscale model
Authors: Lei Yao-Kun , Yagi Kiyoshi , Sugita Yuji
Published: June 2024

The machine learning (ML) method emerges as an efficient and precise surrogate model for high-level electronic structure theory. Its application has been limited to closed chemical systems without considering external potentials from the surrounding environment. To address this limitation and incorporate the influence of external potentials, polarization effects, and long-range interactions between a chemical system and its environment, the first two terms of the Taylor expansion of an electrostatic operator have been used as extra input to the existing ML model to represent the electrostatic environments. However, high-order electrostatic interaction is often essential to account for external potentials from the environment. The existing models based only on invariant features cannot capture significant distribution patterns of the external potentials. Here, we propose a novel ML model that includes high-order terms of the Taylor expansion of an electrostatic operator and uses an equivariant model, which can generate a high-order tensor covariant with rotations as a base model. Therefore, we can use the multipole-expansion equation to derive a useful representation by accounting for polarization and intermolecular interaction. Moreover, to deal with long-range interactions, we follow the same strategy adopted to derive long-range interactions between a target system and its environment media. Our model achieves higher prediction accuracy and transferability among various environment media with these modifications.
Phase autoencoder for limit-cycle oscillators
Authors: Yawata Koichiro , Fukami Kai , Taira Kunihiko , Nakao Hiroya
Published: June 2024

We present a phase autoencoder that encodes the asymptotic phase of a limit-cycle oscillator, a fundamental quantity characterizing its synchronization dynamics. This autoencoder is trained in such a way that its latent variables directly represent the asymptotic phase of the oscillator. The trained autoencoder can perform two functions without relying on the mathematical model of the oscillator: first, it can evaluate the asymptotic phase and the phase sensitivity function of the oscillator; second, it can reconstruct the oscillator state on the limit cycle in the original space from the phase value as an input. Using several examples of limit-cycle oscillators, we demonstrate that the asymptotic phase and the phase sensitivity function can be estimated only from time-series data by the trained autoencoder. We also present a simple method for globally synchronizing two oscillators as an application of the trained autoencoder.
Inferring temperature fields from concentration fields in channel flows using conditional generative adversarial networks
Authors: Cao Hongfan , Kwon Beomjin , Kang Peter K.
Published: June 2024

An accurate estimation of three-dimensional (3D) temperature fields in channel flows is challenging but critical for many important applications such as heat exchangers, radiation energy collectors, and enhanced geothermal systems. In this paper, we demonstrate the possibility of inferring temperature fields from concentration fields for laminar convection flows in a 3D channel using a machine learning (ML) approach. The study involves generation of data using 3D numerical simulations, application of deep learning methodology using conditional generative adversarial networks (cGANs), and analysis of how dataset selection affects model performance. The model is also tested for applicability in different convection scenarios. Results show that cGANs can successfully infer temperature fields from concentration fields, and the reconstruction accuracy is sensitive to the training dataset selected. In this study, we demonstrate how ML can be used to overcome the limitations of traditional heat and mass analogy functions widely used in heat transfer research.
Poisson geometric formulation of quantum mechanics
Authors: Sinha Pritish , Yadav Ankit
Published: June 2024

We study the Poisson geometrical formulation of quantum mechanics for finite dimensional mixed and pure states. Equivalently, we show that quantum mechanics can be understood in the language of classical mechanics. We review the symplectic structure of the Hilbert space and identify its canonical coordinates. We extend the geometric picture to the space of density matrices DN+. We find it is not symplectic but admits a linear su(N) Poisson structure. We identify Casimir surfaces of DN+ and show that the space of pure states PN≡CPN−1 is one of its symplectic submanifolds which is an intersection of primitive Casimirs. We identify generic symplectic submanifolds of DN+ and calculate their dimensions. We find that DN+ is singularly foliated by the symplectic leaves of varying dimensions, also known as coadjoint orbits. We also find an ascending chain of Poisson submanifolds DNM⊂DNM+1 for 1 ≤ M ≤ N − 1. Each such Poisson submanifold DNM is obtained by tracing out the CM states from the bipartite system CN×CM and is an intersection of N − M primitive Casimirs of DN+. Their Poisson structure is induced from the symplectic structure of the bipartite system. We also show their foliations. Finally, we study the positive semi-definite geometry of the symplectic submanifold ENM consisting of the mixed states with maximum entropy in DNM.
Magnetothermal properties of CoO2 monolayer from first-principles and Monte Carlo simulations
Authors: Xu Xing-Long , Hu Cui-E. , Wu Hao-Jia , Geng Hua-Yun , Chen Xiang-Rong
Published: June 2024

Cobalt oxides are known for their excellent heat transfer properties. The main component of cobalt oxides is the CoO2 monolayer, which exhibits high-temperature superconductivity caused by strong electron–phonon coupling (EPC). We here systematically investigate the structural stability, electronic structure, and magnetism of the CoO2 monolayer using first-principles and Monte Carlo simulations. On this basis, we further study the changes in the spin energy gap, magnetic axis direction, and other properties of the CoO2 monolayer with the changes in carrier concentration. By appropriately doping the CoO2 monolayer with holes, the magnetic axis direction of the CoO2 monolayer can be reversed, thereby enhancing its potential application in the field of spin electronic devices. Monte Carlo simulation is used to study the regulation of different factors on the magnetothermal properties of the CoO2 monolayer. Through the analysis of physical parameters such as Curie temperature (TC) and bandgap, we find that the appropriate carrier concentration and magnetic field can not only regulate the magnetothermal properties of materials but also further improve the efficiency of materials in low-temperature environments.
Arrested states in colloidal fluids with competing interactions: A static replica study
Authors: Bomont Jean-Marc , Pastore Giorgio , Costa Dino , Munaò Gianmarco , Malescio Gianpietro , Prestipino Santi
Published: June 2024

We present the first systematic application of the integral equation implementation of the replica method to the study of arrested states in fluids with microscopic competing interactions (short-range attractive and long-range repulsive, SALR), as exemplified by the prototype Lennard-Jones–Yukawa model. Using a wide set of potential parameters, we provide as many as 11 different phase diagrams on the density (ρ)–temperature (T) plane, embodying both the cluster-phase boundary, TC(ρ), and the locus below which arrest takes place, TD(ρ). We describe how the interplay between TC and TD—with the former falling on top of the other, or the other way around, depending on thermodynamic conditions and potential parameters—gives rise to a rich variety of non-ergodic states interspersed with ergodic ones, of which both the building blocks are clusters or single particles. In a few cases, we find that the TD locus does not extend all over the density range subtended by the TC envelope; under these conditions, the λ-line is within reach of the cluster fluid, with the ensuing possibility to develop ordered microphases. Whenever a comparison is possible, our predictions favorably agree with previous numerical results. Thereby, we demonstrate the reliability and effectiveness of our scheme to provide a unified theoretical framework for the study of arrested states in SALR fluids, irrespective of their nature.
Amorphization transition and electrical properties of La2−xCexCuO4 polycrystalline materials
Authors: Zhou Kangjin , Wu Ruifeng , Fu Zhilong , Xian Yue , Chang Aimin , Zhang Bo
Published: June 2024

In contrast to crystals, amorphous materials exhibit distinctive properties and applications due to their unique electronic structure and surface energy. Moreover, the amorphous modification of crystalline materials also results in numerous notable and unique properties. In this study, we propose the amorphous modification of polycrystal La2CuO4 with CeO2, examining the composition of the two phases and changes in the crystal structure. Our findings indicate that the degree of ordering of the La2CuO4 phase significantly decreases as the CeO2 content increases, leading to a resistivity increase in 3–4 orders of magnitude. Furthermore, within the 40–400 K, the transition of the Efros–Shklovskii variable range hopping (E–S VRH) transport mechanism between localized states to the Mott 3D VRH and the crossover around 230 K is observed. The method presented here has great potential in modifying polycrystalline materials by using amorphization to make a sudden increase in resistivity.
Contribution of vibrational excited molecular nitrogen to ammonia synthesis using an atmospheric-pressure plasma jet
Authors: Miyake Atsufumi , Shirai Naoki , Sasaki Koichi
Published: June 2024

The contribution of atomic nitrogen is fairly possible in plasma-assisted catalytic synthesis of ammonia since it has high adsorption probabilities on solid surfaces. On the other hand, recently, the contribution of vibrational excited molecular nitrogen to ammonia synthesis has been discussed. In this work, we compared the fluxes of atomic nitrogen and vibrational excited molecular nitrogen with the rate of plasma-assisted ammonia synthesis. We employed an atmospheric-pressure nitrogen plasma jet, and the spatial afterglow of the plasma jet and a hydrogen flow irradiated the surface of a ruthenium catalyst. The fluxes of atomic nitrogen and vibrational excited molecular nitrogen were measured by two-photon absorption laser-induced fluorescence spectroscopy and laser Raman scattering, respectively. The synthesis rate of ammonia had a positive correlation with the flux of vibrational excited molecular nitrogen, while the variation of the synthesis rate with the gas flow rate was opposite to the flux of atomic nitrogen. The experimental results indicate the contribution of vibrational excited molecular nitrogen to the synthesis of ammonia using the atmospheric-pressure plasma, where the flux of vibrational excited molecular nitrogen is more than four orders of magnitude higher than that of atomic nitrogen.
Alternative CNDOL Fockians for fast and accurate description of molecular exciton properties
Authors: Montero-Cabrera Luis A. , Montero-Alejo Ana L. , Aspuru-Guzik Alan , García de la Vega José M. , Piris Mario , Díaz-Fernández Lourdes A. , Pérez-Badell Yoana , Guerra-Barroso Alberto , Alfonso-Ramos Javier E. , Rodríguez Javier , Fuentes María E. , de Armas Carlos M.
Published: June 2024

CNDOL is an a priori, approximate Fockian for molecular wave functions. In this study, we employ several modes of singly excited configuration interaction (CIS) to model molecular excitation properties by using four combinations of the one electron operator terms. Those options are compared to the experimental and theoretical data for a carefully selected set of molecules. The resulting excitons are represented by CIS wave functions that encompass all valence electrons in the system for each excited state energy. The Coulomb–exchange term associated to the calculated excitation energies is rationalized to evaluate theoretical exciton binding energies. This property is shown to be useful for discriminating the charge donation ability of molecular and supermolecular systems. Multielectronic 3D maps of exciton formal charges are showcased, demonstrating the applicability of these approximate wave functions for modeling properties of large molecules and clusters at nanoscales. This modeling proves useful in designing molecular photovoltaic devices. Our methodology holds potential applications in systematic evaluations of such systems and the development of fundamental artificial intelligence databases for predicting related properties.
Universality of opinions disappearing in sociophysical models of opinion dynamics: From initial multitude of opinions to ultimate consensus
Authors: Wołoszyn Maciej , Masłyk Tomasz , Pająk Szymon , Malarz Krzysztof
Published: June 2024

Possibility of reaching a consensus in social systems with strong initial fragmentation is one of the most interesting issues in sociophysics. It is also intriguing what the dynamics of such processes is. To address those problems, we performed computer simulations using well-established models of social opinion formation, namely, the voter, Sznajd, and Latané models. We investigated opinion dynamics in cases where the initial number of opinions is very large, equal to the number of actors (the voter and Latané models) or when every second actor has their own opinion (Sznajd model), with some variations on the update schemes, lattice topologies, effective ranges of interaction, and information noise levels. For all considered models, the number of opinions assumed by the actors is finally almost always reduced to only one. However, while the voter and Latané models exhibit a power-law time decrease in the number of opinions, the Sznajd model follows a complex three-stage behavior. We also demonstrated the mean/median time of reaching the consensus scales with system size according to a power law for voter and Sznajd models, while for the Latané model, this increase is even faster. Our results show that in the studied models, the consensus is possible, provided that a long enough and model-dependent time to reach this state is available.
Phase field modeling of the detachment of bubbles from a solid substrate
Authors: Uriarte Carlos , Fontelos Marco A. , Arrayás Manuel
Published: June 2024

We develop and implement numerically a phase field model for the evolution and detachment of a gas bubble resting on a solid substrate and surrounded by a viscous liquid. The bubble has a static contact angle θ and will be subject to gravitational forces. We compute, as a function of the static contact angle, the critical Bond number, over which bubbles detach from the substrate. Then, we perform similar studies for bubble resting on inclined substrates and bubbles under the action of an external flow. We provide approximate formulas for the critical Bond number under all these circumstances. Our method is also able to resolve the pinch-off of the bubble and the possible appearance of satellites.
Spiral attractors in a reduced mean-field model of neuron–glial interaction
Authors: Olenin S. , Stasenko S. , Levanova T.
Published: June 2024

This paper investigates various bifurcation scenarios of the appearance of bursting activity in the phenomenological mean-field model of neuron–glial interactions. In particular, we show that the homoclinic spiral attractors in this system can be the source of several types of bursting activity with different properties.
Liquid–solid two-phase flow and separation behavior in a novel cyclone separator
Authors: Chen Hu , Zhang Jian , Liu Shuo , Xu Jingyu
Published: June 2024

In response to the prevalent issue of sand presence in liquid, particularly prominent in petroleum engineering, a novel cyclone separator has been meticulously engineered for fine-particle separation. Experiments and numerical simulation methods have provided a profound understanding of the flow-field characteristics and separation efficacy of this device. The internal architecture of the swirling flow inside the separator features a distinctive central vortex core, complemented by a turbulent secondary vortex formation in the lower section of the underflow. As the axial height increases, the secondary vortex gradually dissipates. An analysis of pressure and velocity distribution within the cyclone separator confirms the establishment of a stable cyclone field in the built-in cyclone and a tendency for the flow field within the tank to exhibit uniformity with increasing height. These flow-field characteristics show that the cyclone separator has a good separation effect on fine-rust particle impurities. Furthermore, the separation efficiency of the novel cyclone separator demonstrates a positive correlation with increasing particle size. Of the parameters studied, variation of the inlet velocity is the best method for obtaining optimum separation efficiency for a cyclone desander with a fixed particle size. Specifically, when the inlet velocity reaches 3 m/s, the desander attains an impressive separation efficiency of up to 70%.
Diagnosis of solid–liquid phase transition using hopping particles in 2D dusty plasmas
Authors: Lu Shaoyu , Huang Dong , Ma Zhuang , Feng Yan
Published: June 2024

Based on the statistical analysis of particles hopping outside the cages formed by their nearest neighboring particles, a new diagnostic of the hopping particle (HP) percentage is proposed to identify the solid–liquid phase transition in two-dimensional (2D) dusty plasmas. To demonstrate the effectiveness of the HP percentage, Langevin dynamical simulations of 2D Yukawa systems under various conditions are performed to mimic 2D dusty plasmas. It is found that the HP percentage exhibits a significant jump while decreasing the coupling parameter around the melting point, just corresponding to the solid–liquid phase transition. As compared with other traditionally used diagnostics, the HP percentage diagnostic is sensitive enough, and the dynamical information is incorporated inside. By comparing to the most widely used diagnostic of the bond-angular order parameter, the melting criterion of this HP percentage diagnostic is determined to be about 30% for the suitable time interval, which is general for the 2D Yukawa systems with different screening parameters.