bluuebunny/crossref_metadata_2025 huggingface dataset:
Florence City Centre Historical Mortars: Digital Image Analysis of thin sections in view of conservation actions
Authors: Lico Alessia , Akouche Maya , Franceschini Matteo Maria Niccolò , Misseri Giulia , Rescic Silvia , Rovero Luisa
Published: September 2024

Conservation actions in historical urban centres must consider compatibility criteria in the selection of repair materials to ensure effective long-term intervention. Along this, compatibility between old and new mortars employed in conservation action requires the characterization of the historical mortar to design a new mortar mix. Digital image analysis (DIA) of thin sections of historical mortars observed under a transmitted polarised light optical microscope appears as an effective methodology for the characterization of mortars. In this work, three samples of bedding mortar were collected from historical monumental buildings of the period between the 14th and 15th centuries, in the city centre of Florence, a UNESCO Heritage Site since 1982, and subjected to petrographic investigation through DIA. Quantitative data about the composition of the analysed historical bedding mortars were determined, such as binder/aggregate ratio, percentage of porosity, the type and the percentage of granulometric selection. The comparison of the results obtained has made it possible to highlight the weaknesses and strengths aspects of the construction technique.
Sustainable Consolidation of Churches that are historic monuments damaged by earthquakes
Authors: Mosoarca Marius , Fofiu Mihai , Gosta Mihai , Hortopan Alexandru
Published: September 2024

Historical buildings were built using local materials and technologies and suffered degradation of their structural elements over time due to abandonment, material degradation, unauthorised interventions or the action of extreme events such as earthquakes. In Romania, there are many historic buildings seriously damaged by earthquakes, which during the communist period were abandoned or strengthened through irreversible interventions with reinforced concrete. In recent years, historic buildings have begun to be consolidated, respecting the principles of sustainability, using mortars with hydraulic lime and composite materials. The article presents sustainable and reversible retrofitting solutions used for the consolidation of historical Orthodox churches in the Gorj area, Romania, severely damaged by the earthquakes of February 2023.
The behaviour of orthodox historic churches built with lime mortar in Romania consolidated with reinforced concrete after the 1977 earthquake
Authors: Mosoarca Marius , Casarin Filippo , Yohei Endo , Fofiu Mihai , Gosta Mihai , Anastasiadis Anthimos , Hortopan Alexandru
Published: September 2024

In Romania, historic monuments have suffered significant damage after earthquakes. In the southern part of Romania, in the Oltenia region between the years 1838 and 1977, five strong earthquakes with magnitude exceeding 7 ML occurred, causing severe and repeated damage to Orthodox churches constructed with brick masonry and lime mortar. After the 1940 earthquake, consolidation was carried out with modern materials for that period, such as metal ties and reinforced concrete. Due to the collapse of the central tower made of brick masonry during the 1977 earthquake in the Church of the Holy Archangels Michael and Gabriel in Craiova, it was reconstructed using reinforced concrete columns and beams. Furthermore, the consolidation was carried out using reinforced concrete. Due to the different mechanical properties of historic brick masonry with lime mortar and reinforced concrete, cracks appeared over time on the church walls in the contact zones between these materials. Under the coordination of Bishop Irineu of Oltenia, consolidation works were initiated for 17 historic monument churches in the Gorj region after the earthquakes in 2023, and this Church in Craiova was included in the list. The article presents the modes and areas of damage resulting from the introduction of consolidations with irreversible materials, together with the results of in situ tests conducted by the EXPIN laboratory in Padua, Italy, to determine the mechanical properties of the load-bearing elements comprising the Church and structural analysis of the Church using ETABS software to predict past, present, and future behaviour.
Importance de la communication avec le propriétaire d’un animal diabétique
Authors: Morand Mathilde , Canonne-Guibert Morgane
Published: September 2024

Une communication de qualité entre un praticien et un propriétaire est la clé d’une bonne éducation et, par-là, de la réussite de la prise en charge des maladies chroniques comme le diabète sucré. Les outils écrits de cette communication sont multiples et sont très valorisés par les propriétaires d’animaux. L’utilisation d’un support écrit permet de garantir la pérennité de l’information, mais aussi de rassurer le propriétaire. Faire de ce dernier l’acteur de la santé de son animal est la preuve de la volonté d’établir un réel partenariat entre propriétaire et praticien.

La demande précédemment évoquée des propriétaires d’obtenir des sources écrites et fiables concernant la santé animale concerne aujourd’hui davantage les supports éducatifs numériques. Les formats numériques permettent l’accès à un volume important d’information, la possibilité de mises à jour fréquentes et un potentiel pour des formats interactifs. L’information médicale à destination des propriétaires d’animaux atteints de diabète est encore aujourd’hui majoritairement constituée de contenu purement éducatif mis à disposition par les cliniques vétérinaires, les centres hospitaliers ou les assurances santé.

L’émergence d’outils numériques mettant à disposition du contenu éducatif et des outils utiles au suivi de la maladie est récente. La mise à disposition de ces outils doit néanmoins être le résultat d’une élaboration réfléchie afin de répondre à la demande des propriétaires tout en assurant la mise à disposition d’une information médicale la plus actualisée possible. Pour cela, des guides de recommandations existent.
Détresse respiratoire chez les rongeurs
Authors: Palmero Audrey , Fieschi Théotime
Published: September 2024

Les causes d’une détresse respiratoire chez les rongeurs sont nombreuses : infectieuse, traumatique, cardiaque, néoplasique, environnementale. La priorité est de placer le patient sous oxygène avec (ou sans) une sédation adaptée afin de réaliser ensuite les examens complémentaires en sécurité. Lors de pneumonie ou d’épanchement, des examens cytobactériologiques et une recherche par PCR de certains virus sont utiles. Des examens d’imagerie sont également nécessaires. En l’attente des résultats, un traitement à base d’oxygénothérapie, d’inhalations, d’anti-infectieux et des soins de soutien (analgésie, perfusion, nourrissage) sont mis en place. Les paramètres environnementaux doivent également être contrôlés.
Cas clinique : Hyperadrénocorticisme et diabète sucré chez un chat
Authors: Etien Hugues , Benchekroun Ghita , Ménard Maud
Published: September 2024

Ce cas clinique illustre le diagnostic d’un hyperadrénocorticisme et d’un diabète sucré chez un chat Européen castré, âgé de 10 ans, présenté pour une polyuro-polydipsie, un amaigrissement, une polyphagie évoluant depuis 3 mois et des troubles cutanés (finesse et perte d’élasticité cutanée, défaut de repousse du poil, télangiectasie). L’association des troubles cutanés et d’un diabète sucré motive rapidement l’exploration d’un hyperadrénocorticisme. Ce dernier est confirmé par la réalisation d’un test de freinage de la cortisolémie par la dexaméthasone à dose faible. La visualisation d’une masse surrénalienne associée à une atrophie de la glande controlatérale est évocatrice d’une origine surrénalienne. Une hypokaliémie et une hypertension artérielle systémique sont également mises en évidence lors de l’exploration, faisant suspecter un hyperaldostéronisme concomitant. Dans ce cas, la masse surrénalienne était probablement à l’origine d’une sécrétion mixte. Un traitement médical est mis en place (trilostane 2 mg/kg une fois par jour), permettant de diminuer les signes cliniques et de diminuer la dose d’insuline requise à l’équilibre du diabète sucré. Le traitement chirurgical est décliné étant donné le risque de complications important.
Les gliflozines, des inhibiteurs du cotransporteur sodium-glucose de type 2 (SGLT2)
Authors: Benchekroun Ghita
Published: September 2024

Le traitement traditionnel du diabète sucré chez le chat repose sur l’insulinothérapie, mais celle-ci est contraignante et parfois inefficace. Les inhibiteurs des cotransporteurs sodium-glucose de type 2 (SGLT2), comme la vélagliflozine et la bexagtiflozine, représentent une alternative prometteuse. Ces médicaments réduisent la réabsorption rénale du glucose, favorisant ainsi son excrétion et normalisant la glycémie, ce qui peut permettre une amélioration de la fonction des cellules bêta pancréatiques. Leur administration est orale et nécessite une sélection rigoureuse des candidats pour éviter des complications telles que l’acidocétose diabétique. Les chats sans cétose ni maladies chroniques graves sont de bons candidats pour ce traitement. Bien que des effets secondaires comme la diarrhée puissent survenir, ils sont généralement temporaires et auto-résolutifs. Un suivi rapproché est crucial durant les premières semaines de traitement pour prévenir les complications. Les perspectives thérapeutiques incluent l’association des gliflozines avec l’insuline et l’éventuelle rémission du diabète après un traitement prolongé.
Exploring the incidence of dysplasia or adenocarcinoma in early onset Barrett’s esophagus
Authors: Noordzij Irma C. , Huysentruyt Clément J. , Curvers Wouter L. , van Lijnschoten Gesina , Masclee Ad A. M. , Schoon Erik J.
Published: September 2024

Background Currently data on the risk of progression to and lifetime risk of cancer are not available for patients with young onset Barrett’s esophagus (BE). Our aim was to obtain epidemiologic data on the incidence of dysplasia or adenocarcinoma in young onset BE in the Netherlands by collecting data on all histologically confirmed cases over a prolonged period of 25 years between January 1, 1991 and December 31, 2015.

Methods Data were obtained from the Dutch National Pathology Registry. Patients were included if there was a suspicion of BE visualized in the esophagus during the endoscopic examination in combination with a concordant histologic diagnosis of intestinal metaplasia.

Results 231 patients with early onset BE were identified (median age 26 years [range 0–29 years]), with 17 progressing to dysplasia (6 prevalent and 11 incident). For the patients with incident dysplasia, the median surveillance time between the diagnosis of early onset BE and diagnosis of dysplasia was 5 years (range 0–16 years). The incidence rate of dysplasia was 7.3 per 1000 person-years. There were three patients who developed adenocarcinoma (1 prevalent and 2 incident), who were diagnosed at ages 28, 35, and 36 years. The incidence rate of adenocarcinoma was 1.3 per 1000 person-years.

Conclusions In this 25-year period, 231 patients were diagnosed with early onset BE in the Netherlands, with 17 patients progressing to dysplasia and three developing adenocarcinoma. This corresponded to incidence rates of 7.3 per 1000 person-years for dysplasia and 1.3 per 1000 person-years for adenocarcinoma.
Evaluation of the aspherical surface of a plano–convex lens by refraction using an LCD
Authors: Huerta-Carranza Oliver , Granados-Agustín Fermín Salomon , Santiago-Alvarado Agustín , Campos-García Manuel , Avendaño-Alejo Maximino
Published: September 2024

We present a simple method to evaluate the curved surface of a plano–convex aspheric lens using an incoherent light source. We implement an exact ray trace to obtain analytical expressions for designing a set of geometric objects, placed within a plane, to produce by refraction a regular array of either circles or straight lines in the plane of detection when the optical system under test works in accordance with the nominal design. An innovative geometrical test is implemented to calibrate the position of each element involved in the measurement system. As part of the calibration process, we considered that the camera lens can be affected by the distortion aberration; therefore, we proposed a straightforward method to compensate for the defects introduced in the experimental images. Finally, we used the measured values of the slopes to recover the shape of the surface under test using an iterative algorithm; as a result, we obtained the geometric parameters describing the surface with a percentage error less than 1.7%.
Selective control of valley polarization in monolayer transition metal dichalcogenides among multiexcitonic states
Authors: Liang Lun , Yang Di , Liu Wen , Qu Fanyao , Hao Ning , Zhang Ping , Fu Jiyong
Published: September 2024

In 2018, an inverted valley polarization (VP) for the biexciton emission in monolayer WS2 was experimentally observed [Nagler et al., Phys. Rev. Lett. 121, 057402 (2018)]. Here, we develop a comprehensive model, which incorporates thermal effect and magnetic response of exciton and biexciton complexes with both intra- and intervalley relaxation channels, to reveal the underlying physics. We obtain the inverted biexciton VP, in excellent agreement with the experimental data. Notably, beyond available experimental measurements, our theory also predicts a reversal of VP for excitons associated with the intra- and intervalley thermalization processes, greatly fascinating for selective VP control among distinct excitonic states. These (i) open a pathway toward valley exciton based field-effect transistor and (ii) make possible a concept of “excitonic filter,” which resembles spin filter while with functionality of selectively filtering excitonic states, offering an intriguing platform for spintronic and orbitronic as well as valleytronic combined applications. A comparison with other W-based and even Mo-based monolayers of transition metal dichalcogenides including WSe2, MoSe2, and MoS2 is also made.
Thermodynamic evaluation of metal foams with partial filling in a pipe
Authors: K Kiran Kumar , Kotresha Banjara , Naik Kishan
Published: September 2024

This study presents numerical findings on the flow and heat transfer irreversibility when metal foams are partially filled in a horizontal pipe. A heater is embedded in the pipe's circumference with a known heat input. Aluminum metal foam, characterized by a pore density of 10 and porosity of 0.95, is placed next to the inner wall of the pipe to enhance heat transfer. To determine the optimal thickness of the metal foam for thermodynamic performance enhancement, metal foams of five different thicknesses (10–80 mm) are examined under forced convection heat transfer conditions. The study integrates the Darcy Extended Forchheimer and local thermal nonequilibrium models to predict flow and heat transfer characteristics through the metal foams. Validation of the numerical methodology is conducted by comparing the results with experimental data available in the literature. A novel aspect of this investigation is the application of the second law of thermodynamics to analyze the thermodynamic performance of metal foams. Exergy and irreversibility analyses are used to evaluate the thermodynamic performance, revealing that a pipe filled with metal foams up to a thickness of 40 mm exhibits superior thermodynamic performance compared to other cases examined in the study.
Lack of differentiability in nonlocal nonsimple porous thermoelasticity with dual-phase-lag law
Authors: Zeng Shengda , Aouadi Moncef
Published: September 2024

In this paper we consider the nonlocal theory for porous thermoelastic materials based on Mindlin’s strain gradient theory with nonlocal dual-phase-lag law. This makes the derived equations more physically realistic, as they overcome the infinite propagation velocity property of the Fourier law. This approach consists of adding the second strain gradient and the second volume fraction gradient field to the set of independent constituent variables. We then obtain a system of three second order time equations with higher gradient terms. Using semigroup theory, we show the well-posedness of the one-dimensional problem. By an approach based on the Gearhart–Herbst–Prüss–Huang theorem, we prove that the associated semigroup is exponentially stable but not differentiable. The lack of analyticity and the impossibility to localize the solutions in time are direct consequences.
Research on a new pressure pulsator
Authors: Yong Su , Wu-Qi Gong
Published: September 2024

Pulsators are widely used to study the dynamic characteristics of liquid flow components. However, it is difficult to adapt the existing actuators to the excitation requirements under high pressures, low temperatures, and toxic media. This study describes the design of a novel pressure pulsation device and presents the results of simulations and experimental tests. The flow field is simulated under a series of working conditions, and the effects of the rotation speed, flow rate, inlet pressure, and gap between the rotor and stator on the peak-to-peak amplitude, spectral amplitude, and flow resistance coefficient of the actuator outlet are analyzed. A prediction model for the corresponding parameters is developed using multiple linear regression. In high-pressure (20 MPa) hydraulic pipeline tests, the excitation device can generate pulsating flow with peak-to-peak amplitudes of more than 7 MPa in the time domain and 2 MPa in the frequency domain. The upstream and downstream regions of the internal flow field are periodically joined and detached by the blade rotation, which results in periodic variations in flow velocity and pressure. The relative error between the model predictions and the three-dimensional simulation and experimental values is less than 7%, satisfying industrial requirements. This work facilitates a solution to the problem of dynamic excitation when analyzing the response characteristics of fluid equipment in high-pressure pipelines and provides a method for forecasting actuator output effects.
Unidirectional propagation of zero-momentum magnons
Authors: Wojewoda Ondřej , Holobrádek Jakub , Pavelka Dominik , Pribytova Ekaterina , Krčma Jakub , Klíma Jan , Panda Jaganandha , Michalička Jan , Lednický Tomáš , Chumak Andrii V. , Urbánek Michal
Published: September 2024

We report on experimental observation of unidirectional propagation of zero-momentum magnons in synthetic antiferromagnet consisting of strained CoFeB/Ru/CoFeB trilayer. Inherent non-reciprocity of spin waves in synthetic antiferromagnets with uniaxial anisotropy results in smooth and monotonous dispersion relation around Gamma point, where the direction of the phase velocity is reversed, while the group velocity direction is conserved. The experimental observation of this phenomenon by intensity-, phase-, and time-resolved Brillouin light scattering microscopy is corroborated by analytical models and micromagnetic simulations.
A customizable data management framework for high-repetition-rate high-energy-density science
Authors: Manuel M. J.-E. , Keller A. , Linsenmayer E. , Collins G. W. , Sammuli B. , Margo M.
Published: September 2024

The high-energy-density (HED) physics community is moving toward a new paradigm of high-repetition-rate (HRR) operation. To fully leverage the scientific power of HRR HED facilities, all of the components of each subsystem (laser, targetry, and performance diagnostics) must be connected and synchronized in a reliable and robust manner while the data acquired are tagged and archived in real time. To this end, GA has begun developing a generalized NoSQL-database framework, the MongoDB repository for information and archiving. An organizational strategy has been developed that shifts HED data organization from a shot-based to a diagnostic-based approach in order to increase archival and retrieval efficiency that lends itself to optimization applications. This work is a first step in pushing HRR HED science toward data management solutions that emphasize machine actionability and aim to stimulate community engagement to define data standards in HED science.
Study on the influence of labyrinth seal structure on the performance of shrouded stator cascades with inter-stage cavities
Authors: Huang Tianshuo , Kong Xiaozhi , Lu Huawei , Fan Pengwei , Dong Zhengyang
Published: September 2024

Numerical simulations of a shrouded stator cascade with an inter-stage cavity were conducted using validated numerical methods to investigate the impact of different labyrinth seal structures and positions on the aerodynamic performance of the stator cascade. The study discussed the development trends of secondary flow motion and corner separation within the cascade under different labyrinth seal structures, evaluated the stator performance using total pressure loss coefficient and entropy-based loss coefficient, and revealed the interaction between cavity leakage flow and mainstream flow. The results indicate that individually changing the labyrinth seal structure or position has a negligible impact on stator performance, but simultaneously altering both the structure and position of the labyrinth seal can effectively reduce stator losses. The structure case 1-position case 2 labyrinth seal structure can reduce total pressure loss by 6.25%, while structure case 4-position case 4 reduces entropy increase loss coefficient by 7.67%. Additionally, it was found that changing the labyrinth seal structure and position can increase the circumferential velocity and momentum of cavity leakage flow at the cavity outlet, enhance the resistance of cavity leakage flow to circumferential secondary flow within the stator passage, and reduce stator losses. Altering the structure and position of the labyrinth seal effectively reduces the cavity leakage vortex at the leading edge of the cascade during the mixing process of cavity leakage flow with the mainstream, causing the passage vortex to move rearward axially.
A novel stress sensor enables accurate estimation of micro-scale tissue mechanics in quantitative micro-elastography
Authors: Metzner Kai L. , Fang Qi , Sanderson Rowan W. , Yeow Yen L. , Green Celia , Abdul-Aziz Farah , Hamzah Juliana , Mowla Alireza , Kennedy Brendan F.
Published: September 2024

Quantitative micro-elastography (QME) is a compression-based optical coherence elastography technique enabling the estimation of tissue mechanical properties on the micro-scale. QME utilizes a compliant layer as an optical stress sensor, placed between an imaging window and tissue, providing quantitative estimation of elasticity. However, the implementation of the layer is challenging and introduces unpredictable friction conditions at the contact boundaries, deteriorating the accuracy and reliability of elasticity estimation. This has largely limited the use of QME to ex vivo studies and is a barrier to clinical translation. In this work, we present a novel implementation by affixing the stress sensing layer to the imaging window and optimizing the layer thickness, enhancing the practical use of QME for in vivo applications by eliminating the requirement for manual placement of the layer, and significantly reducing variations in the friction conditions, leading to substantial improvement in the accuracy and repeatability of elasticity estimation. We performed a systematic validation of the integrated layer, demonstrating >30% improvement in sensitivity and the ability to provide mechanical contrast in a mechanically heterogeneous phantom. In addition, we demonstrate the ability to obtain accurate estimation of elasticity (<6% error compared to <14% achieved using existing QME) in homogeneous phantoms with mechanical properties ranging from 40 to 130 kPa. Furthermore, we show the integrated layer to be more robust, exhibiting increased temporal stability, as well as improved conformity to variations in sample surface topography, allowing for accurate estimation of elasticity over acquisition times 3× longer than current methods. Finally, when applied to ex vivo human breast tissue, we demonstrate the ability to distinguish between healthy and diseased tissue features, such as stroma and cancer, confirmed by co-registered histology, showcasing the potential for routine use in biomedical applications.
Impact of helium nanobubbles on tungsten fuzz nanostructure conductivity
Authors: Tsventoukh M. M. , Kulagin V. V.
Published: September 2024

Explosive electron emission splashes occurring in plasma interactions with nanostructured surfaces can be induced by Joule energy release under reduced conductivity. Distribution of helium nanobubbles inside tungsten at an elevated energy of implanted helium ions has been studied via numerical molecular dynamic modeling, and its impact on the nanostructure conductivity has been estimated. Average concentration and size of nanobubbles were calculated to be about n = 1020 cm−3 and r = 3 Å, respectively, at the helium fluence of about 2 × 1015 cm−2. The distribution of nanobubbles becomes more flat and extends deeper into the bulk material with increasing impact energy. At energies below about 300 eV, most nanobubbles form within a depth of 10 nm, corresponding to the characteristic size of the nanowires. At higher energies, a significant portion of the nanobubbles forms deeper in the material. An approach for estimating the electron scattering frequency in tungsten by helium nanobubbles has been proposed, taking into account the volume porosity of the W-fuzz nanostructure and scaling the helium content to the experimentally measured one. The resulting value for the tungsten fuzz nanostructure was 2.27 × 1016 s−1 and the resistivity was 1.92 mΩ cm that is 364 times larger than the normal tungsten resistivity, the conductivity of 521 S/cm was 0.275% from the normal tungsten one. The corresponding estimation of thermal conductivity via Wiedemann–Franz law gave 3.8 mW cm−1 K−1, which agrees well with recent measurements.
Trapping mechanism transition of γ-ray irradiation on p-GaN gate stack on gate applying voltage swing
Authors: Zhu Junyan , Ding Jihong , OuYang Keqing , Zou Xinbo , Ma Hongping , Li Liang , Zhang Debin , Zhou Jianjun , Qiu Yiwu , Zhou Xinjie , Wang Tao , Huang Wei , Zhang David Wei
Published: September 2024

The total ionizing dose effect of Mg-doped p-GaN gate stack have been investigated in this Letter on the whole gate voltage swing arranging from −1.3 to +1.5V. Additionally, two distinct kinds of mechanisms of trap effects have been extracted, which are response to in turns three phases of mechanism, voltage-controlled, coexist of voltage/current-controlled and current-controlled. It indicates that the fast traps are located at p-GaN/AlGaN interface (ET is about 0.295–0.333 eV), while the slow traps are located at AlGaN/GaN interface (ET is about 0.393–0.485 eV). They both have increasing trap density and broader range under γ-ray radiation. When the applied gate voltage rises to about 1 V, the effects of slow trap states are significantly weakened. However, the fast trap states barely change. Finally, the complete transition into current-controlled mode is observed at 1.5 V. What is more, p-GaN/AlGaN interface traps are further extracted near the gate turn-on voltage under γ-ray irradiation rather than the voltage-controlled mechanism of weak accumulation at the threshold voltage. Under the 600 krad γ-ray irradiation, the holes trap at p-GaN/AlGaN interface is identified with the trap activation energy ET at about 0.28–0.3 eV and trap density of about 4 × 1012 cm−2 eV−1. The increase in trap induces the reduction of gate current. In summary, this work can further our understanding of radiation tolerance and trapping effects of p-GaN gate high-electron mobility transistors for power switches, especially in regard to forward conduction status.
Mapping Rashba-spin-valley coalescence in two-dimensional monolayers via high-throughput first-principles calculations
Authors: Arora Anu , Sharma Shivam , De Sarkar Abir
Published: September 2024

This study delves into the interplay of symmetry and structure in 2D systems to identify monolayers hosting valley physics together with the Rashba effect. Through high-throughput density functional theory calculations, 57 monolayers are identified exhibiting the Rashba effect, with the Rashba parameter αR spanning from 0 <  αR < 2.0. The robustness of the Rashba parameters (αR) in these monolayers is primarily influenced by the physical parameters, highlighting the anti-crossing of Rashba-split bands and the Born effective charge (Z*). Among the 57 monolayers exhibiting the Rashba effect, the study identifies a subset of 23 monolayers presenting valley physics, demonstrating both in-plane and out-of-plane spin polarizations. The pronounced coupling of the valley and Rashba spin splitting is influenced by the in-plane and out-of-plane orbital contributions at the relevant K-points in the band spectra. In particular, the AB-type buckled structures feature these dual properties due to the presence of the broken inversion and mirror symmetries in them. Overall, the study eases the identification of monolayers with significant spin splitting and spin polarization, aiding in the design of high-performance 2D materials.
Electromechanical properties and piezoelectric potentials of one-dimensional GaN nanostructures: A bond relaxation investigation
Authors: Liu Jin , Zhu Min , Yang Xuexian , Yang Liwen
Published: September 2024

From the viewpoint of atomic bond relaxation, an analytical approach was put forward to elucidate the physical origins of crystal size and cross-sectional shape dependency of piezoelectric potentials in GaN nanowires and nanotubes. It is demonstrated that (i) size-induced increase in piezoelectric potential is attributed to the coupling effect of the rising piezoelectric coefficient and both the reducing dielectric constant and elastic constant caused by the surface atomic coordination number loss, bond energy perturbation, and surface-to-volume ratio rising; (ii) as the number of sides for polygonal nanowires or nanotubes with the same equivalent radius decreases, the surface-to-volume ratio rises, and the piezoelectric potential increases; and (iii) the nanotubes can generate a piezoelectric potential higher than their nanowire counterparts due to their larger surface-to-volume ratios. The proposed formulation offers a scientific basis for the fabrication, optimization, and modulation of one-dimensional GaN-based piezoelectric nanometer devices.
Anti-diffusion method for coupled level set and volume of fluid, volume of fluid, and tangent of hyperbola for interface capturing methods
Authors: Yokoi Kensuke
Published: September 2024

In this paper, we propose an anti-diffusion method to effectively prevent flotsams (non-physical tiny droplets and bubbles) and/or diffusion of the VOF (volume of fluid) function that occur in CLSVOF (coupled level set and volume of fluid), VOF (volume of fluid), and THINC (tangent of hyperbola for interface capturing) methods. In the proposed method, VOF functions that are not 1 or 0 and exist at a certain distance from the interface are identified as flotsams and/or diffusion (Cad), and these VOF functions (Cad) are moved to the transition region around the interface, where the VOF value is between 0 and 1, using a conservative advection method to prevent flotsams and/or diffusion. Additionally, the proposed method allows for some control over the position to which Cad is moved within the transition region. As a result of applying the proposed anti-diffusion method to various benchmark tests and droplet problems, it was found that the proposed method effectively suppresses flotsams and/or diffusion while ensuring conservation. In some cases, the anti-diffusion method even improves interface capture accuracy. Furthermore, investigating the impact of the position to which Cad is moved revealed that when handling Cad occurring on the gas side (liquid side), moving Cad as far as possible from the gas side (liquid side) increases the effectiveness of flotsams suppression.
Discovering the incorporation limits for wurtzite AlPyN1−y grown on GaN by metalorganic vapor phase epitaxy
Authors: Yang Xu , Furusawa Yuta , Kano Emi , Ikarashi Nobuyuki , Amano Hiroshi , Pristovsek Markus
Published: September 2024

We report on the growth of AlPN on GaN/sapphire templates by metalorganic vapor phase epitaxy using tertiarybutylphosphine (tBP) and NH3 as group-V precursors. P is easy to incorporate into the group-III lattice site, forming PAl anti-site defects and shrinking lattice constants that are even beyond AlN since Al is larger than P. We found that higher temperatures favor P incorporation on the N-sublattice, forming AlPyN1−y, while growth temperatures below 1000 °C result in dominant P incorporation on the Al-sublattice, forming PAl anisites. Similarly, larger NH3 flows stabilize GaN, leading to flat interfaces, but favor the formation of PAl. Furthermore, the P incorporation into AlPyN1−y is non-linear. At very low tBP flows, it initially increases to reach a maximum. Further increasing the tBP flow increases mostly the incorporation of P on the Al-sublattice, and the c-lattice constant decreases again. This leaves a small window of low V/III ratios below 5 and low P/N ratios of 1% or smaller, leading up to ∼4% P incorporation at typical growth temperatures of GaN. However, at such low V/III ratios, GaN is not stable even with N2 carrier gas and requires optimized switching sequences to minimize its decomposition and preserve flat interfaces. Eventually, a 10 nm coherent layer of AlP0.01N0.99 could be reproducibly grown on top of GaN channels with a smooth surface, an abrupt AlPN/GaN interface, and a two-dimensional electron gas with an electron mobility of ∼675 cm2/V s and a sheet carrier density of 1.5 × 1013 cm−2 at room temperature.
Evaluation of turbulence models for the prediction of flow properties in vegetated channels
Authors: Sibil (Şibil) Rahim
Published: September 2024

The performance of turbulence models was investigated to predict the flow and turbulence features of the vegetated channel using computational fluid dynamics (CFD). The Ansys Fluent, CFD software was implemented for the numerical studies. The flow was three-dimensional, incompressible, steady, and turbulent. Ten turbulence models, provided by Ansys Fluent, were implemented for the comparative study. The numerical model was validated against an experimental study conducted in the literature. The numerical studies show that the Renormalization group k–ε model is the most successful model for predicting the flow characteristics of the vegetated channel with a Root Mean Square Error (RMSE) value of 0.2752. At the same time, the Reynolds Stress Model gives the least successful predictive performance, indicated by an RMSE value of 0.4302. Moreover, the Spalart–Allmaras (S–A) model offers the shortest computation time with a value of 6652.393 s, whereas the Shear Stress Transport k–ω model proves to be the most time-consuming with a value of 11 952.219 s. The velocity of water flow in a channel is not uniform as it is slower at the surface of leaves and faster in the free zones. The maximum velocity is observed in the middle section of the channel, below the leaf, and between the roots with the value of u = 0.1158 m/s. Furthermore, the characteristics of turbulence in a channel are influenced by several factors such as channel geometry, flow velocity, and vegetation distribution. As a result, the presence of vegetation in a channel affects the flow and turbulence characteristics of the water significantly.
Short-time self-diffusion in binary colloidal suspensions
Authors: Ruzzi V. , Buzzaccaro S. , Moretti P. , Piazza R.
Published: September 2024

The Brownian dynamics of a colloidal particle is consistently modified by the presence in the solvent of other particles of comparable size, whose effects on the particle diffusion coefficient cannot be attributed to a change of the effective solvent viscosity. So far, despite their impact on subjects ranging from microrheology to phoretic transport in crowded environments, a detailed experimental survey of these effects is still lacking. By exploiting the peculiar properties of fluorinated colloidal particle, we have performed an extensive dynamic light scattering (DLS) investigation of short-time self-diffusion in binary colloidal mixtures, focusing on systems where one of the two species (the “tracer” particles) is very diluted compared to the other one (the “host” particles). From the dependence on the host concentration of the DLS correlation function, we have obtained the first-order correction hs1s to the tracer single-particle diffusion coefficient, varying the tracer-to-host size ratio q in the range 0.2 ≤ q ≤ 2. Our results support the functional relation of hs1s on q proposed to account for the theoretical and numerical results for hard-sphere mixtures. However, hs1s seems to have a weaker dependence on the size ratio than theoretically predicted, possibly because of an imperfect matching of the suspensions we used for an ideal hard-sphere mixture. This may be due to the presence of a stabilizing surfactant layer on the particle surface that, although very thin, has significant effects on hydrodynamic lubrication forces.
Advancing semantic segmentation of two-dimensional materials using a semantic-adaptive transformer model
Authors: Cheung Wing-Sing , You Min-Hsuan , Syu Si-Yao , Chou Yu-Hsun , Chen Chi-Yeh
Published: September 2024

Accurate detection and characterization of two-dimensional (2D) materials are essential for their effective utilization in various applications. Traditional techniques, such as chemical vapor deposition, often produce materials with high defect density, while mechanical exfoliation is hindered by its labor-intensive and time-consuming nature. In this Letter, we propose a semantic-adaptive transformer model, termed Semptive, designed specifically for the precise detection of monolayer MoS2. Our approach integrates a semantic adaptation module with a multi-head self-attention mechanism, incorporating deep supervision and leveraging prior knowledge to enhance model performance. The model was trained on a dataset obtained through mechanical exfoliation and validated using photoluminescence spectroscopy. The experimental results reveal that Semptive significantly enhances segmentation performance compared to conventional models, achieving higher Intersection over Union and Dice scores while reducing computational demands. This method represents a notable advancement in the efficient and precise identification of 2D materials, providing substantial improvements for material characterization and device fabrication processes.
Spatially resolved luminescence properties of etched quantum well microstructures
Authors: Landesman J. P. , Diak E. , LaPierre R. R. , Levallois C. , Ghanad-Tavakoli S.
Published: September 2024

Ridge microstructures were prepared by etching through samples consisting of a series of stacked InAsxP1−x quantum wells (QWs) with step graded composition grown on InP by molecular beam epitaxy. Different etching techniques were used: wet etching with HCl/H2O and reactive ion etching with CH4/H2. These microstructures were characterized by low-temperature micro-photoluminescence. The photoluminescence (PL) emission associated with each QW was clearly identified. The PL was measured in detail across etched ridge stripes of various widths. Variations of the integrated PL intensities across the etched stripes were observed. The PL intensities for all QWs increase gradually from the edge to the center of the ridge microstructures. The PL intensity measured at the ridge center is systematically reduced for ridges which are 10 or 20 μm wide as compared to ridges which are 30 μm wide or larger. On the other hand, the spectral peak position of the PL lines remained constant with high accuracy (0.2–0.4 meV) across the microstructures. These observations are discussed in terms of the different possible mechanisms which determine the PL intensity variations, namely, non-radiative recombination at the etched walls and effects of stray electric fields which result from the etching process. Based on this discussion, we compare quantitatively the different etching processes which we have used. Altogether, this study illustrates the contribution that specially designed test structures, coupled with advanced spectroscopic characterization, can provide to the development of semiconductor photonic devices (e.g., lasers or waveguides) involving etching processes.
Bimolecular photodissociation of interstellar 1-Cyanonaphthalene via Intermolecular Coulombic decay
Authors: Dutta Saurav , Behera Nihar Ranjan , Barik Saroj , Kushawaha Rajesh Kumar , Sajeev Y. , Aravind G.
Published: September 2024

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in space and govern the interstellar chemistry. The two isomers of cyanonaphthalene (1-CNN and 2-CNN) were the first PAHs to be recently identified in the Taurus Molecular Cloud (TMC-1). Their large abundance is attributed to high photostability with nearly no photofragmentation at photon energies above the ionization potential. Here, we show that at ambient light and at densities akin to dense molecular clouds and the upper atmosphere of planets and moons, 1-CNN could undergo extensive fragmentation through a new mechanism leading to daughter cations. On UV photoexcitation, at a photon energy way below the ionization threshold, 1-CNN monomers form photoexcited dimer units. Intermolecular Coulombic decay between the two photoexcited units of the dimer leads to ionization, and the subsequent molecular rearrangements form new daughter cations. These daughter cations could react further, contributing to rich bottom-up astrochemistry, and could play a pivotal role in developmental astrobiology. Photofragmentation in atmospheric and astrophysical environments is hitherto known to be unimolecular, while the present results point a pathway involving bimolecular photofragmentation.
Synchronization transitions in a system of superdiffusively coupled neurons: Interplay of chimeras, solitary states, and phase waves
Authors: Fateev I. , Polezhaev A.
Published: September 2024

In this paper, a network of interacting neurons based on a two-component system of reaction-superdiffusion equations with fractional Laplace operator responsible for the coupling configuration and nonlinear functions of the Hindmarsh–Rose model is considered. The process of synchronization transition in the space of the fractional Laplace operator exponents is studied. This parametric space contains information about both the local interaction strength and the asymptotics of the long-range couplings for both components of the system under consideration. It is shown that in addition to the homogeneous transition, there are regions of inhomogeneous synchronization transition in the space of the fractional Laplace operator exponents. Weak changes of the corresponding exponents in inhomogeneous zones are associated with the significant restructuring of the dynamic modes in the system. The parametric regions of chimera states, solitary states, phase waves, as well as dynamical modes combining them, are determined. The development of filamentary structures associated with the manifestation of different partial synchronization modes has been detected. In view of the demonstrated link between changes in network topology and internal dynamics, the data obtained in this study may be useful for neuroscience tasks. The approaches used in this study can be applied to a wide range of natural science disciplines.
Effects of Nd substitution on the magnetic properties and the frequency of natural resonance peak in Y2Fe17
Authors: Wu Wei , Wu Peng , Yang Shengyu , Wang Wenbiao , Tu Chengfa , Wang Tao , Li Fashen , Qiao Liang
Published: September 2024

In this study, the excellent Y2−xNdxFe17 (x = 0, 0.2, 0.4, 0.6, 0.8) magnetic particles were prepared by the reduction–diffusion process. Through the ferromagnetic coupling between light rare earth element Nd and Fe atoms, we effectively modulated the magnetic crystallographic anisotropy of Y2Fe17. As the amount of Nd doping increases, the natural resonance frequency of Y2−xNdxFe17/PU increases to 15.7 GHz, the saturation magnetization increases to 120.43 emu/g, the Curie temperature increases to 390 K, and the average hyperfine field also increases to 22.5 T. Notably, the doping of Nd atoms leads to a slight expansion of the Y2−xNdxFe17 lattice, exhibiting distinct anisotropic characteristics that preferentially develop along the basal plane. The doping of rare earth Nd atoms with strong magnetic crystal anisotropy can not only significantly enhance the easy-plane magnetic crystallographic anisotropy, causing the natural resonance peak to shift toward higher frequencies, but also has important guiding significance for broadening the high-frequency application range of easy-plane rare earth transition metal alloys. This achievement provides new ideas and methods for the design and development of high-performance magnetic materials.
Stereoscopic cells of three-dimensional detonation waves propagating in square ducts
Authors: Yao Kepeng , Wang Chun , Han Guilai , Jiang Zonglin
Published: September 2024

The present study delves into the examination of the stereoscopic cells and wavefront structures characterizing the propagation of three-dimensional detonation waves within square ducts. Leveraging numerical solutions derived from three-dimensional reactive Euler equations, incorporating an induction-exothermic reaction kinetic model, this work reveals the distinct classification of three modes of detonation waves based on the direction of propagation and the phase characteristics of transverse shock waves on the wavefront. This paper delineates the presence of two different types of phenomena: duct wall slapping waves due to shock–wall collisions and internal slapping waves resulting from shock interactions. Furthermore, this investigation exposes the existence of two distinct types of triple-wave lines on the wavefront: the first comprising a strong Mach disk, a weak Mach disk, and a transverse shock wave; the second characterized by a weak Mach disk, an incident shock wave, and a transverse shock wave. Notably, the pressure behind the first type of triple-wave line is observed to be the highest. It elucidates the transition from two- to three-dimensional detonation waves, revealing that the prevalence of transverse shock waves on the wavefront in the rectangular and diagonal modes is twofold and quadruple, respectively, when compared to their two-dimensional counterparts within identical ducts/channels.