bluuebunny/crossref_metadata_2025_split huggingface dataset:
Caseload and In-Hospital Outcome of Carotid Surgery Performed during the COVID-19 Pandemic vs. Previous Years: A Single-Centre Analysis
Authors: Westreicher Werner , Goidinger Alina , Gruber Ingrid , Grams Astrid , Knoflach Michael , Wipper Sabine , Kluckner Michaela , Klocker Josef 
Published: September 2024

AbstractWith the beginning of the COVID-19 pandemic in March 2020, restrictions and challenges for elective and emergency vascular surgery as well as worse outcomes were reported. This study aims to compare our single-centre experience with carotid artery surgery during the pandemic and previous years.Our retrospective analysis included all consecutive patients undergoing carotid surgery for symptomatic and asymptomatic stenosis between January 2017 and December 2021. Caseload, operation specific parameters, and demographic data as well as in-hospital outcome were compared during the COVID-19 pandemic versus previous years.A total of 623 consecutive patients were included. The caseload comparison showed an average of 112 carotid artery surgeries per adjusted year (March 16th to December 31st) from 2017 to 2019, prior to the pandemic. The caseload reduction in the first year of the pandemic (2020) was 36.6% (n = 71) and 17.9% (n = 92) in the second year (2021). No rebound effect was observed. There was no significant difference (p = 0.42) in the allocation of symptomatic and asymptomatic patients (asymptomatic patients: 37.1% prior vs. 40.8% during the pandemic; symptomatic patients: 62.9 vs. 59.2%). Major adverse event rates in years prior to the pandemic were postoperative bleeding requiring revision: n = 31 (7.1%); stroke in symptomatic patients: n = 9 (3.3%) and stroke in asymptomatic patients: n = 4 (2.5%); symptomatic myocardial infarction (MCI): n = 1 (0.2%); death: n = 2 (0.5%). During the pandemic, major adverse event rates were postoperative bleeding requiring revision: n = 12
(6.5%); stroke in symptomatic patients: n = 1 (0.9%), stroke in asymptomatic patients: n = 1 (1.3%); symptomatic MCI: n = 1 (0.5%); death: n = 1 (0.5%).Since the beginning of the COVID-19 pandemic in March 2020, there has been a significant reduction in carotid artery surgery performed both in symptomatic as well as in asymptomatic patients. There was no worsening of the outcome of carotid surgery performed during the COVID-19 pandemic, and this remained safe and feasible.
The “simple” photochemistry of thiophene
Authors: Parkes Michael A. , Worth Graham A. 
Published: September 2024

The static gas-phase (“simple”) ultraviolet absorption spectrum of thiophene is investigated using a combination of a vibronic coupling model Hamiltonian with multi-configuration time-dependent Hartree quantum dynamics simulations. The model includes five states and all 21 vibrations, with potential surfaces calculated at the complete active space with second-order perturbation level of theory. The model includes terms up to eighth-order to describe the diabatic potentials. The resulting spectrum is in excellent agreement with the experimentally measured spectrum of Holland et al. [Phys. Chem. Chem. Phys. 16, 21629 (2014)]. The, until now not understood, spectral features are assigned, with a combination of strongly coupled vibrations and vibronic coupling between the states giving rise to a progression of triplets on the rising edge of the broad spectrum. The analysis of the underlying dynamics indicates that population transfer between all states takes place on a sub-100 fs timescale, with ring-opening occurring at longer times. The model thus provides a starting point for further investigations into the complicated photo-excited dynamics of this key hetero-aromatic molecule.
Controlling size and distribution of Au nano-particles on C3N4 for high-efficiency photocatalytic hydrogen production
Authors: Ran Xunan , Chen Zhihua , Ji Hongzhou , Ma Zhaoyu , Xie Yuxi , Li Wenping , Zhang Junying 
Published: September 2024

With advantages such as low cost, high stability, and ease of production, visible light photocatalytic C3N4 with a unique microscopic layered structure holds significant potential for development. However, its hydrogen production efficiency remains low due to the pronounced recombination of photo-generated charge carriers and limited surface reaction sites. Normally, the photocatalytic performance of C3N4 can be enhanced by loading noble metals with surface plasmon resonance. It is worth noting that the size of noble metal nanoparticles has a great influence on photocatalytic performance. In this study, accurate controlling of the size and distribution of Au nanoparticles was achieved on the surface of C3N4 by introducing amino groups to improve photocatalytic performance. Results show that uniformly distributed Au nanoparticles in the range of 2–6 nm can be obtained on C3N4 with a remarkable enhancement of hydrogen production efficiency, which is about 114 times the property of pure C3N4. The small-sized and uniformly distributed Au nanoparticles can provide more reaction sites and increase the separation of photo-generated charge carriers, in turn improving Au/NH3–C3N4 photocatalytic hydrogen release rate to 6.85 mmol g−1 h−1. This work offers a facile way to enhance photocatalytic performance by controlling the size of metal nanoparticles on C3N4 precisely.
Functional variations in efficiency of PSII during leaf ontogeny in the tropical plant Saraca asoca
Authors: Shasmita   , Swain Barsha Bhushan , Mishra Smrutirekha , Mohapatra Debasish , Naik Soumendra Kumar , Mohapatra Pradipta Kumar 
Published: September 2024

Leaf ontogeny of tropical evergreen tree species lasts several months with changes in size, shape, colouration and internal tissue distribution of leaves. Leaf initiation in Saraca asoca generally occurs once in a year during February–April, followed by very limited leafing thereafter. We measured the rate of photosynthesis, chlorophyll a fluorescence, energy quenching and PSII functions during the leaf ontogeny process. Observations were taken up to 35 days after opening of lamina (DAOL). Significant increase in the synthesis and accumulation of photosynthetic pigments but negative net photosynthesis was noticed during initial days of the ontogeny. The leaf moved from heterotrophy to autotrophy with gradual improvement of PSII functions. The ratio of intercellular CO2 (Ci) and ambient CO2 (Ca) showed significant change at ≥11 DAOL. Increase in the age of the leaf (between 5 and 28 DAOL) caused decrease in O-J rise and corresponding increase in J-I and I-P rise as well as of fluorescence maximum (FM) of the OJIP curve. The improvement of the electron transport components of the donor side of PSII was seen with increase in the functional oxygen evolving complex. The functional improvements of the donor and acceptor side of PSII during leaf ontogeny are discussed.
An energy perspective on Galileo’s kinematic paradox
Authors: Hailu Dawit Hiluf 
Published: September 2024

Abstract
The connection between kinematics and work–energy principles is often not emphasized enough for students to appreciate fully. Highlighting the relationship between the kinematic equations and the conservation of total mechanical energy is crucial. We revisit the solution to Galileo’s kinematic paradox from an energy perspective. Galileo stated that the time it takes for an object to travel from the top to the bottom point of a vertical circle is the same regardless of its path. While mathematical proofs of this statement using kinematic approaches are well-documented, this paper explores the problem from an energy standpoint, using experimental evidence to elucidate the relationship between kinematics and energy.
Advances in timing and control of ultrafast molecular dynamics: from XUV to infrared
Authors: Jiang Wenyu , Pan Shengzhe , Huang Hao , Tong Jihong , Zhang Wenbin , Ni Hongcheng , Wu Jian 
Published: September 2024

Abstract
With the availability of modern laser and detection technologies, the investigation of ultrafast molecular dynamics induced by intense laser pulses has become a routine practice. In this Topical Review, we present a survey of recent progress in the timing and control of ultrafast molecular dynamics, encompassing processes initiated by both extreme ultraviolet and near infrared pulses. Prospects and perspectives of this field are given. This Review underscores the remarkable potential for further advances in understanding and harnessing ultrafast molecular processes.
Electron-impact excitation data for W2+ in support of tungsten spectroscopy and re-deposition measurements for magnetically-confined plasmas
Authors: McCann M , Ballance C P , Loch S D , Ennis D A 
Published: September 2024

Abstract
To better understand plasma wall interactions involving tungsten, accurate atomic structure and electron-impact driven collisional processes for near-neutral ion stages of tungsten are required. Complementing existing work on neutral and singly ionised tungsten, atomic structure and collisional calculations for W2+ electron-impact excitation have been completed. These excitation calculations are an important component of S/XB coefficients for near-neutral charge states, which may be used to spectroscopically infer re-deposition of tungsten at the plasma-solid boundary of fusion relevant devices. With W2+ in particular having emission lines that can be observed at ultraviolet (UV) wavelengths, while higher charge states of tungsten are unlikely to have lines possible to observe outside of the vacuum UV range. The atomic structure was generated using the General-purpose Relativistic Atomic Structure Package (GRASP0), implementing the Multi-configuration Dirac Fock approach. This structure was the basis for a subsequent Dirac R-matrix electron-impact excitation calculation to provide Maxwellian averaged rate coefficients. A synthetic spectrum was generated from this data using a collisional-radiative model to predict the strongest W III spectral lines and these lines were compared to emission from the Compact Toroidal Hybrid (CTH) plasma device. Several of the strongest W III lines are observed in CTH and agree well with the modelled line wavelengths and intensities, a table of these lines is provided that could be observed in other devices.
Effects of anode evaporation process on the anode sheath characteristics in vacuum arc plasma
Authors: Liu Zhaohui , Song Mengmeng , Wang Ziming , Yang Wei , Dong Ye , Sun Qiang , Zhou Qianhong 
Published: September 2024

Abstract
The anode sheath of vacuum arc plasma plays a key role in the generation of anode plasma, but the effects of anode evaporation on the anode sheath remains unclear. In this paper, a theoretical model of a collisional sheath for multi-component plasma coupled with anode evaporation is developed, and the spatial evolution of the anode sheath at different anode surface temperatures is investigated. The results indicate that the distribution of charged particles density and potential in the anode sheath monotonically decreases in the absence or reduction of anode evaporation. When the anode surface temperature exceeds 1900 K, a potential hump appears within the sheath. This is due to enhanced anode evaporation increasing the metal vapor density, which intensifies electron impact ionization and charge exchange collisions, resulting in a higher net space charge density. Finally, the effects of various collision reactions and electron temperatures on the potential hump are analyzed. These findings are meaningful for understanding the anode plasma generation mechanism and regulating the anode plasma parameters.
Development characteristics of rod-plate Gap streamer-leader system at high altitude areas
Authors: Wang Ping , Ma Wenchuang , Zhang Hang , Geng Jianghai , Liu Yunpeng , Luo Bing , Liu Lei , Xiao Wei , Zhong Zheng 
Published: September 2024

Abstract
Air density is an important factors affecting the morphology characteristics of long air gap discharge channels. Analyzing characteristic parameters, such as the propagation velocity and angle of the streamer-leader system at high altitude areas is indispensable in studying the discharge mechanism of long gaps. In this paper, optical images and optical power of the discharge channel were captured. The propagation velocity of the streamer-leader system and angle distribution characteristics of the streamer region were obtained. In accordance with the findings, the downward velocity of the streamer-leader system at low pressure ranges from 1 × 104 to 5 × 104 m s−1. Simultaneously, the velocity decreases slightly under the voltage with a low rise rate, and it is often accompanied by the phenomenon of leader re-luminescence. In addition, the optical images were processed by the pseudo-color algorithm, and the angle of the streamer region of the downward leader head was obtained between 50.3° and 71.6°. The angle of the streamer region is inversely correlated with the voltage rise rate but positively correlated with the gap distance. The results obtained in this paper have academic significance for improving the theoretical system of long gap discharge in high-altitude extreme environments.
Dulac maps of real saddle-nodes
Authors: Ilyashenko Yu 
Published: September 2024

Abstract
Consider a germ of a holomorphic vector field at the origin on the coordinate complex plane. This germ is called a saddle-node if the origin is its singular point, one of its eigenvalues at zero is zero, and the other is not. A saddle-node germ is real if its restriction to the real plane is real. The monodromy transformation for this germ has a multiplier at zero equal to 1. The germ of this map is parabolic and admits a ‘normalizing cochain’. In this note we express the Dulac map of any real saddle-node up to a left composition with a real germ

(

C

,
0
)
→
(

C

,
0
)

through one component of the cochain normalizing the monodromy transformation.
A facile method of deriving solar selective nickel-cobalt oxide thin films via spraying process
Authors: Farhan Ghofran K , Taha Hatem 
Published: September 2024

Abstract
The present study focuses on synthesizing solar selective absorber thin films, combining nanostructured, binary transition metal spinel features and a composite oxide of Co and Ni. Single-layered designs of crystalline spinel-type oxides using a facile, easy and relatively cost-effective wet chemical spray pyrolysis method were prepared with a crystalline structure of MxCo3−xO4. The role of the annealing temperature on the solar selective performance of nickel-cobalt oxide thin films (∼725 ± 20 nm thick) was investigated. XRD analysis confirmed the formation of high crystalline quality thin films with a crystallite size in the range of 27–52 nm. The highest solar absorptance (∼85.2%) and the lowest thermal emittance (∼4.45%) along with the highest values of both hardness and the Young’s modulus (19.1 GPa and 104 GPa, respectively) were obtained for the film annealed at 600 °C. In addition, the synthesized nickel-cobalt oxide thin films show band gap energies in the range of 1.15–1.38 eV and excellent thermal stability at higher temperatures, which makes them interesting candidates for solar absorbing applications.
Complex nonlinear dynamics of a multidirectional energy harvester with hybrid transduction
Authors: Costa Luã G , Savi Marcelo A 
Published: September 2024

Abstract
Mechanical energy harvesting has increasing scientific and technological interests due to novel energetic challenges. A critical issue in classical cantilever-based mechanical energy harvesting systems is the lack of multidirectional energy conversion capabilities and, due to that, deviations from the excitation source can drastically reduce their performance. This limitation has led to the development of energy harvesters with attached pendula, serving as a direction coupling mechanism. Nevertheless, the pendulum structure itself can act as an energy absorber, drastically reducing the harvester performance in certain scenarios. In order to overcome this issue, a hybrid multidirectional pendulum-based energy harvester has been introduced by the authors. The hybrid transduction integrates a piezoelectric element to capture energy from the principal direction and an electromagnetic transducer to harness rotational energy from the pendulum. This paper presents an in-depth analysis of the hybrid multidirectional pendulum-based energy harvester using a nonlinear dynamics perspective to evaluate the energy harvesting performance. A reduced-order model is proposed to represent the essential characteristics of such systems. A parametric analysis using a nonlinear dynamics perspective is carried out to map the system dynamics and performance. The emergence of complex and rich dynamics is observed, including chaos and hyperchaos. Results reveal the most and least effective combinations of structural parameters in terms of energy conversion. Additionally, the dynamical responses and patterns associated with high performance are identified. These responses are often characterized by a blend of irregular complex behaviors, coupled with a mix of oscillatory and rotational patterns of motion, resulting in wider bandwidth systems.
Modeling of dynamic characteristics and μ-synthesis control of piezoelectric positioning platform
Authors: Duan Shiyu , Liu Haotian , Zhang Guilin 
Published: September 2024

Abstract
The dynamic hysteresis nonlinearity and various uncertainties of the piezoelectric positioning platform are critical factors limiting its high-precision applications. To address this, the dynamic characteristics of the piezoelectric positioning platform under various loads are identified based on the linearization of the Prandtl–Ishlinskii inverse model. The inverse compensation error and load disturbances are attributed to model uncertainties, which are modeled in the frequency domain. A μ-synthesis controller is designed to improve the tracking accuracy of the piezoelectric positioning platform under uncertainty disturbances. The experimental results of sine wave tracking indicate that with the μ-synthesis controller, the piezoelectric positioning platform achieves a relative error (RE) of less than 2.71% when unloaded. The RE is less than 6.03% for load disturbances of 100 g, 200 g, and 300 g, respectively. These results demonstrate that the designed controller meets the high-precision positioning performance requirements under various load disturbance conditions.
Microwave loss and kinetic inductance of epitaxial TiN films
Authors: Wu Yu , Liu Yixin , Gao Wanpeng , Wang Xiaoni , He Xiaoliang , Jin Hua , Peng Wei , Mu Gang , Lin Zhirong , Wang Zhen 
Published: September 2024

Abstract
Low microwave loss and regulatable kinetic inductance are two key characteristics of superconducting films to manufacture high-performance quantum devices. Epitaxial titanium nitride (TiN) thin films have been found to exhibit significant advantages in these two aspects. In this paper, we investigated into the dielectric loss and kinetic inductance of epitaxial TiN films, which were prepared on both silicon and sapphire substrates with different temperatures. Crystal structure, surface morphology, and superconducting properties were characterized systematically. The radio-frequency response of microwave resonators made of TiN films was studied at low temperatures to extract the information of kinetic inductance and quality factor. We obtained the highest internal quality factor up to

1.6
×

10

6

at single photon regime and achieved a regulation of kinetic inductance exceeding 16 times by altering the substrate and the sputtering temperature of the TiN films. This work not only provides an essential foundation for the precise design and preparation of low-loss TiN resonators for superconducting quantum bits, but also demonstrates TiN film as an excellent material platform with both low microwave loss and high kinetic inductance that can be applied in other fields such as microwave kinetic inductance detectors.
Effective spin models and magnetic phases of an insulating bosonic ladder with unconventional synthetic flux
Authors: Pan Zong-Zhen , Yang Shi-Jie , Zheng Yi 
Published: September 2024

Abstract
We investigate the Mott insulating phases of a two-component bosonic lattice gas in the presence of gauge field. Such a system is described by a two-leg ladder model with an unconventional flux. The synthetic flux is generated by the spin-dependent tunneling and the site-dependent spin-flip. In the Mott regime, these two effects lead to Dzyaloshinskii-Moriya (DM) interaction and an external field that is rotating in the xy-plane. We obtain a very general XYZ model with the DM interaction, the spiral field, and the transverse field. Various interesting magnetic Hamiltonians can be covered by adjusting lattice parameters. The DM interaction or the spiral field can lead to spiral order when they appear alone. The interplay of DM coupling and spiral field leads to the emergence of a new multi-frequency spiral order between the paramagnetic phase and the spiral ferromagnetic phase. Ground state phases are investigated by focusing on order parameters, spin-spin correlation functions, and structure factors. Calculations are performed by using time evolution block decimation (TEBD) based on matrix product state (MPS).
Characterization of graphite and ZrO2 reinforced aluminium metal matrix composite for enhanced mechanical properties in electronics applications
Authors: I Duraimurugan , K Anandavelu , R Pandiyarajan 
Published: September 2024

Abstract
The objective of this work is to examine the wear properties of a hybrid Metal Matrix Composite (MMC) consisting of 92 weight percent (wt%) Aluminium Alloy 6061 (AA6061), 2 wt% Graphite (C), and 6 wt% Zirconium Dioxide (ZrO2). It was previously determined that this composition was ideal for improved metallurgical and mechanical properties. Nine specimens of the same composition were fabricated for this continuation work and put through wear tests with different applied load, sliding velocity, and sliding distance settings. To evaluate the performance of the composite, measurements were made of the wear rate and Coefficient of Friction (COF). According to the results, the wear rate typically increased as the applied load and sliding velocity increased. At the lowest load (10 N) and velocity (2 m s−1), the lowest wear rate (50.90 μg) and COF (0.197) were noted. Specimens with lower wear rates had smoother surfaces and less wear, as revealed by SEM analysis of the worn surfaces; specimens with higher wear rates showed more significant surface damage, such as deeper cuts and serrations. In specimens with less wear, XRD analysis verified the presence of crystalline aluminium, indicating a strong correlation between wear resistance and the crystalline structure of the composite. Linear regression equations were created to predict wear behavior under different conditions. According to the results, the composite’s wear characteristics are greatly influenced by the sliding velocity and applied load. ZrO2 and C together have lubricating and strengthening properties that, under certain circumstances, reduce wear. The composite exhibits potential for usage in electronics applications, especially in components where wear resistance and mechanical durability are critical due to its favorable wear characteristics and mechanical properties.