bluuebunny/crossref_metadata_2025 huggingface dataset:
Utiliser la lumière pour voir dans les coins
Authors: Christnacher Frank , Laurenzis Martin , Schertzer Stéphane , Bacher Emmanuel
Published: July 2024

Les nouvelles caméras SPAD (Single Photon Avalanche Diodes) présentent aujourd’hui des performances époustouflantes. Comme leur nom l’indique, elles sont sensibles à un seul photon de lumière, leur résolution temporelle ne cesse d’augmenter pour arriver actuellement à la picoseconde, et certaines matrices atteignent déjà le Mpixels. De telles caractéristiques laissent entrevoir des applications dont on ne pouvait que rêver il y a encore peu : voir la lumière se propager dans l’air (light-in-flight imaging), faire des capteurs à temps de vol flirtant avec des résolutions spatiales de l’ordre du mm, ou encore aller voir dans les coins (non-line-of-sight imaging, NLOS). C’est cette dernière application que nous allons développer dans cet article.
Evaluating the Overall Quality of Online Information on Nuclear Power Plant Accidents in Japanese
Authors: Ito Shinya , Furukawa Emi , Okuhara Tsuyoshi , Okada Hiroko , Kiuchi Takahiro
Published: July 2024

Information on professionally produced materials is beyond the reading level of the average adult and is difficult to read and understand. Additionally, the readability of nuclear emergency preparedness manuals in Japan is not clear. The purpose of this study is to evaluate the understandability, actionability, readability, and quality of nuclear emergency preparedness manuals. A systematic quantitative content analysis of online resources was conducted from November 27 to December 8, 2023. The selection criteria were websites in Japanese related to nuclear disaster prevention and aimed at the general public. The PEMAT-P, jReadability, Journal of the American Medical Association benchmark criteria, and Global Quality Scale were used to evaluate each web page. The number of respondents who scored 70 or higher on the PEMAT-P was 71 (61.2%) for Understandability and 57 (49.1%) for Actionability. Regarding the difficulty level of the texts by jReadability, "Difficult" was the most frequent response with 82 responses (70.7%). The JAMA Benchmark Criteria was 35.3% in 41 patients for attribution, 80.2% in 93 patients for currency, and a mean GQS of 4.1 (SD=1.0). This study quantitatively evaluated the understandability, actionability, readability, and quality of nuclear disaster prevention materials for the Japanese public. The findings suggest that text pertaining to nuclear disaster prevention materials may not be easily understood because it is beyond the reading comprehension of the average adult.
A note on the dislocation hyperbolic transformation function
Authors: Ramirez Lennin Mallma , Maculan Nelson
Published: July 2024

In work of Roman A. Polyak [R.A. Polyak, Math. Program. 92 (2002) 197–235.], the Modified Chen-Harker-Kanzow-Smale (CHKS) function was studied to relate a multiplier method and an Interior Prox method with the second order distance function. Independently, the dislocated hyperbolic penalty function (DHPF) was proposed by A.E. Xavier (1992). DHPF was rewritten and studied in [L. Mallma Ramirez, N. Maculan, A.E. Xavier and V.L. Xavier, RAIRO:RO 57 (2023) 2941–2950.] and [L. Mallma Ramirez, N. Maculan, A.E. Xavier and V.L. Xavier, J. Convex Anal. To appear (2024).]. Thus, this function was called the dislocated hyperbolic function (DHF). In this work, we note that DHF is a particular case of CHKS function. Then we will call the DHF function as the dislocation hyperbolic transformation function.
A study on N-policy BMAP/G/1 queueing system
Authors: Bank Bivas , Samanta Sujit Kumar
Published: July 2024

This study presents a simple approach for analyzing the BMAP/G/1 queueing system under N policy. In this policy, the server goes idle at the end of a busy period and the queue length is checked at every arrival moment. The idle server starts serving customers when the queue length reaches or above a predetermined number, namely N, and keeps doing so until the system is completely empty. We first use a simple sequential substitution approach to derive the system length distribution at departure epoch. A comparative study is also conducted to highlight the benefits and strength of our straightforward approach to that of the RG-factorization technique and the roots finding method. We extract the distribution of system length at a random time point by utilizing the remaining service time of a customer who is currently being served as the supplementary variable. The probability density function of the sojourn time distribution for an arbitrary customer of an incoming batch is also computed. We propose an expected linear cost function to estimate the optimal value of N at minimum cost. The validity of our analytic technique has been shown through a variety of numerical examples involving different service time distributions.
Avaliação de diferentes técnicas de preparação de terreno na instalação de povoamentos de eucalipto
Authors: Oliveira António , Mendes Eduardo , Quintela Ana , Fabres Sérgio , Ventura Pedro , Santos Tiago , Pato Rosinda , Silva João , Gomes Filomena
Published: July 2024

Este trabalho foi desenvolvido no âmbito do projeto “Instalação eficiente de povoamentos de eucalipto” com o objetivo de estudar alternativas de mobilização do solo ajustadas à escala da propriedade (minifúndio dominante no Centro/Norte do país), associadas a menor intervenção e impacto ambiental. Foram consideradas para comparação algumas técnicas de mobilização utilizadas em propriedades de maior dimensão. Instalaram-se 4 ensaios na região Centro (três em Cantanhede e um em Mortágua; cada um com 65 a 270 plantas, considerando 3 repetições). A rearborização com eucalipto implicou em todos os casos destroçamento de cepos com enxó. O tratamento convencional - “Operacional” consistiu numa gradagem contínua seguida de ripagem. Em Cantanhede foram colocados dois tratamentos a teste: T1 ripagem (tri-riper) e T2 coveamento (com enxó) para plantação entre cepos. Em Mortágua, devido à dimensão das varas, diferentes opções de gestão de sobrantes foram testadas. O tratamento “Operacional”, com a incorporação de sobrantes durante a gradagem, foi comparado com os tratamentos teste “TA” e “TB”, ambos sem gradagem e, ainda, sem vs. com remoção de sobrantes, respetivamente. Nos tratamentos “TA e TB” testou-se a ripagem na linha (ripado) vs. coveamento na linha de plantação (coveado). Em Mortágua, comparou-se ainda com a construção de terraços, técnica generalizada na região, dada a orografia com declive acentuado. Ao fim de um ano, nos 4 ensaios, os tratamentos em teste não diferiram significativamente do operacional no tocante à taxa de sobrevivência. Mas, em Cantanhede (nos 3 ensaios), o tratamento operacional apresentou um acréscimo em altura significativamente superior aos tratamentos teste. O acréscimo em altura mostrou variar numa razão direta com os teores em matéria orgânica do solo e potássio. Ao fim de 3 anos, o volume médio/árvore não mostrou diferenças significativas entre os tratamentos (Operacional vs. Teste), em 2 ensaios em Cantanhede, mantendo-se significativamente superior no outro ensaio. Em Mortágua a altura média superior foi de 2,75±0,06m (1 ano) em terraços (tratamento com maior mobilização do solo), mas, sem diferenças significativas para o TA-coveado (alinhamento de resíduos na entrelinha e coveamento na linha). No âmbito do projeto tenciona-se dar continuidade à monitorização dos ensaios no sentido de corroborar os resultados do presente estudo obtidos na fase inicial do ciclo de crescimento do povoamento, altura em que as técnicas de preparação do terreno terão, previsivelmente, maior impacte.
Functionalization of Position 7 of Pyrazolo[1,5-a]pyrazines
Authors: Kostyuk Aleksandr , Koidan Georgyi , Tsyzoryk Nazar , Rusanov Eduard B. , Shishkina Svitlana V. , Vovk Mykhailo
Published: July 2024

We report a straightforward formylation at position 7 of pyrazolo[1,5-a]pyrazine derivatives featuring substituents at the 2,3,4 positions. N,N,N′,1,1,1-Hexamethylsilanecarboximidamide exists in equilibrium with its carbene form due to 1,2-migration of the silyl group. The ensuing carbene can be inserted into the most acidic C–H group of the pyrazolo[1,5-a]pyrazines. The most acidic calculated pK
a (DMSO) C–H group is at position 7 and does not depend significantly on the substituents. The reactions proceed in high yields affording aminals that can be hydrolyzed to the corresponding aldehydes. Methanolysis of the aminals affords the corresponding methylimines. The constitution of the aminals was unambiguously proved by X-ray crystal structure analysis of a set of derivatives. The method is simple, often does not require even solvents, and can be extended to other heterocyclic compounds.
Patient-Reported Outcomes and Complications of Simultaneous versus Staged Surgical Decompression for Tandem Spinal Stenosis
Authors: Hussain Mustafa Mushtaq , Khalil Mujtaba , Suleman Fatima , Ali Iqra Fatima Munawar , Masroor Mehar , Shamim Muhammad Shahzad
Published: July 2024

Introduction Tandem spinal stenosis (TSS) refers to the narrowing of the spinal canal at two distinct anatomic areas. Symptoms can present due to either cervical myelopathy or lumbar stenosis. Consequently, determining the symptomatic anatomical levels requiring surgery can pose a challenge. We sought to identify the surgical approach associated with better patient-reported outcomes.

Materials and Methods The Information Management System was queried using the International Classification of Diseases Ninth and Tenth Edition codes to identify patients who underwent simultaneous or staged decompression surgery for TSS between 2011 and 2020. Patient records were reviewed to collect data on age, sex, comorbidities, surgical approach, modified Japanese Orthopedic Association (mJOA) score, and complications. The mJOA is a validated composite assessment used to quantify postoperative neurological status. Multivariable regression models were utilized to identify factors associated with better postoperative neurological recovery.

Results Among 42 patients included in the analytical cohort, 33 (78.6%) underwent simultaneous cervical and lumbar decompression, while 9 (21.4%) underwent staged decompression (cervical followed by lumbar). The patient's age, sex, comorbid conditions, and American Society of Anesthesiologists level were similar between the two groups. Furthermore, simultaneous decompression was associated with higher blood loss (676.97 vs. 584.44 mL) and an increased need for transfusion (259.09 vs. 111.11 mL) compared with staged decompression. Moreover, patients who underwent simultaneous decompression experienced a higher number of postoperative complications (10 vs. 1; p = 0.024). Notably, postoperative mJOA scores improved in both groups; however, the improvement was more pronounced in the staged group (mJOA score: 15.16% [ ± 2.18] vs. 16.56% [ ± 1.59]). On follow-up visits, patients who underwent staged decompression showed better recovery rates (mJOA score: 78.20% [ ± 24.45] vs. 59.75% [ ± 25.05]).

Conclusion The patient's clinical history and examination findings should be the main determinants of surgical decision-making. Our study showed a slightly higher postoperative mJOA score and a recovery rate with fewer complications in staged decompression of TSS.
A netnographic study to understand the determinants of experiential tourism destinations
Authors: Küster Inés , Vila Natalia
Published: July 2024

Considering the Social Identity Theory in an experiential tourism destination and using a netnoghaphic perspective, this paper (i) analyses the main topics associated with an experiential tourism destination and (ii) studies the relationships among destination determinants (i.e., destination attachment, hedonic emotions, spiritual experiences, and information, satisfaction, and loyalty). Camino de Santiago 518 effective post titles published on TripAdvisor were scrapped and analysed using a netnographic and correspondence analyses. Results show that there are three main topics associated with an experiential destination: (1) experiences and emotions, (2) information about Camino de Santiago, and (3) destination-brand recommendations. There is a main cluster where destination loyalty, destination identity, hedonic emotions, and negative experiences/aspects are close to the 5-score. A second cluster focused on information comments is not associated with other variables or scores. This article adds value to previous work because (1) it adopts a netnographic point of view, (2) it uses social media and user-generated content in the tourism industry, and (3) it provides strategies for experiential marketing in the tourism industry.
Transient amplification due to non-Hermitian interference of dissipative supermodes
Authors: Makris Konstantinos G.
Published: July 2024

Achieving transient amplification of light in coupled waveguides that are characterized by a fully dissipative spectrum, is the context of our study. Physically, material gain is present and spatially distributed in a lossy lattice, and thus makes possible the interesting effect of transient growth. In order to quantify the maximum value of power growth and determine the accompanying optimal initial conditions, we apply pseudospectra and singular value decomposition techniques. Similar to the way we can identify all possible microstates of a paramagnetic crystal for a given value of energy, we can also calculate the maximum transient growth of all different permutations of the gainy channels for given values of gain–loss amplitudes, and thus sort them. The result of such non-Hermitian hierarchy is that we have maximum amplification, when the gain is distributed close to the lattice's edges.
Drag exerted by drift-acoustic radiation on a magnetic island
Authors: Cancino-Escobar M. S. , Martinell J. J. , Waelbroeck F. L.
Published: July 2024

The Island Equilibrium and Transport (IslET) model is extended to allow for the effects of ion compressibility albeit for a constant electron temperature. The model describes fully relaxed, saturated, steady-state magnetic islands arising from the evolution of a tearing mode caused either by an instability or an externally imposed resonant perturbation. It assumes that the collision frequency lies in the semi-collisional regime. A salient new feature of the extended model is an equation describing the transport of parallel momentum. The model is applied to evaluate the drag exerted on a thin island by the emission of drift-acoustic waves.
Generation of terahertz radiation through nonlinear Thomson scattering by two moderate-intensity laser fields
Authors: Hong Xue-Ren , Shi Ke , Liang Shi-Ya , Li Lie-Juan , Tang Rong-An
Published: July 2024

A new scheme for the generation of the terahertz (THz) radiation based on the nonlinear Thomson scattering is proposed through two moderate-intensity laser fields. It is found that the THz radiation can be generated in the nonlinear Thomson backscattering spectrum by two moderate-intensity plane wave laser fields with no need of a strong external magnetic field. In this scheme, the amplitude threshold required to generate the THz radiation for two laser fields can be significantly reduced, and the amplitude threshold can even be less than half that of the case of using only a single laser field. It is also shown that in the two moderate-intensity laser fields, the intensity of the THz radiation can also be effectively improved and optimized by increasing the amplitude ratio and reducing the frequency ratio of the two laser fields, and extending the period of the electron motion via the control of the frequency ratio.
Flexible thin-layer plasma sterilizer based on polyimide and efficacy evaluation under bending deformation
Authors: Sun Yu-Hao , Liu Yuan-Yang , Zhang Bo , Zhao Hang , Sun Ming-Yang , Fan Lei , Zhang Guan-Jun
Published: July 2024

Cold atmospheric pressure plasma is receiving attention in biomedical treatment for its non-thermal, dry-type, and high-efficiency disinfection effects on bacteria, fungi, and viruses, compared to typical sterilization methods, such as pasteurization, chemical solutions, and ultraviolet radiation. There are great demands of plasma decontamination on the surface of complex 3D objects, with the request of large coverage, convenience, and uniformity, which still remains a challenge for the current plasma devices. In this work, a flexible thin-layer plasma source for sterilization is developed based on a polyimide substrate, and its plasma generation process is characterized by experiment and simulation. The influences of bending deformation are studied and evaluated by electrical waveforms, heat radiation, and ozone production, of which the mechanisms are further explained. Results illustrate that the variation in electron impact ionization induced by different curvatures is the main cause leading to the change in microparticle production, thus affecting the macroscopic properties of plasmas. Activations of the plasma sterilizer for 30 and 120 s reduce both S. aureus and P. aeruginosa on the flat surface by around 2.5 and 5 log colony forming units (CFU). However, the plasma sterilization effect decreases with an extent of about 1 log CFU when treating the curved surface, while being regained after conforming the plasma sterilizer to the curved surface. This kind of plasma generator offers significant flexibility and efficacy, being promising for the treatment of objects with irregular surfaces in future plasma biomedicine and material processing.
Local augmentation of phonon transport at GaInN/GaN heterointerface by introducing a graded variation of InN mole fraction
Authors: Shwe Thee Ei Khaing , Asaji Tatsuya , Iida Daisuke , Najmi Mohammed A. , Ohkawa Kazuhiro , Ishitani Yoshihiro
Published: July 2024

The pump and probe technique in Raman spectroscopy of the E2 (high) mode is exploited to uncover the enhancing factor of the phonon transport across Ga1−xInxN/GaN interfaces. Two samples are investigated: one with a uniform x of 0.09 and another one with a graded variation in x from 0.17 to 0 along the depth direction. Lateral phonon transport is obtained by scanning the 532-nm probing laser from the irradiation position of the 325-nm heating laser. No difference in the lateral diffusion length is observed between the two samples, while the transport probability across the interface is higher for the sample with the graded variation in x than the sample with the uniform x of 0.09. The microscopic images of the decrease in the mode energy or the increase in temperature of the GaN layer reveal that the local phonon transport across the heterointerface is enhanced in regions with low differences in the phonon mode energy between the GaN and GaInN rather than the difference in crystal quality.
RLC resonator with diode nonlinearity: Bifurcation comparison of numerical predictions and circuit measurements
Authors: Hellen Edward H.
Published: July 2024

A nonlinear RLC resonator is investigated experimentally and numerically using bifurcation analysis. The nonlinearity is due to the parallel combination of a semiconductor rectifier diode and a fixed capacitor. The diode’s junction capacitance, diffusion capacitance, and DC current–voltage relation each contribute to the nonlinearity. The closely related RL-diode resonator has been of interest for many years since its demonstration of period-doubling cascades to chaos. In this study, a direct comparison is made of dynamical regime maps produced from simulations and circuit measurements. The maps show the variety of limit cycles, their bifurcations, and regions of chaos over the 2D parameter space of the source voltage’s frequency and amplitude. The similar structures of the simulated and experimental maps suggest that the diode models commonly used in circuit simulators (e.g., SPICE) work well in bifurcation analyses, successfully predicting complex and chaotic dynamics detected in the circuit. These results may be useful for applications of varactor-loaded split ring resonators.
Nonlinear susceptibilities and higher-order responses related to physical aging: Wiener–Volterra approach and extended Tool–Narayanaswamy–Moynihan models
Authors: Moch Kevin , Gainaru Catalin , Böhmer Roland
Published: July 2024

Large-amplitude thermal excursions imposed on deeply supercooled liquids modulate the nonlinear time evolution of their structural rearrangements. The consequent aftereffects are treated within a Wiener–Volterra expansion in laboratory time that allows one to calculate the associated physical-aging and thermal response functions. These responses and the corresponding higher-harmonic susceptibilities are illustrated using calculations based on the Tool–Narayanaswamy–Moynihan (TNM) model. The conversion from laboratory to material time is thoroughly discussed. Similarities and differences to field-induced higher-harmonic susceptibilities are illustrated using Lissajous and Cole–Cole plots and discussed in terms of aging nonlinearity parameters. For the Lissajous plots, banana-type shapes emerge, while the Cole–Cole plots display cardioidic and other visually appealing patterns. For application beyond the regime in which conventional single-parameter aging concepts work, the Wiener–Volterra material-time-series is introduced as the central tool. Calculations and analyses within this general framework in conjunction with suitable choices of higher-order memory kernels and employing correspondingly extended TNM models yield at least qualitative agreement with recent large-perturbation physical aging experiments. Implications for differential scanning calorimetry and related methods are discussed. The introduced concepts and analyses provide a solid foundation for a generalized description of nonlinear thermal out-of-equilibrium dynamics of glass forming materials, differing from the nonlinear responses known from rheology and dielectric spectroscopy.
Complex shock structure in multi-species dusty plasma with nonextensive electrons and two-temperature nonthermal ions
Authors: Tanisa N. Y. , Ferdousi M. , Saaduzzaman D. M.
Published: July 2024

A theoretical investigation has been made to explore the behavior of nonplanar (cylindrical and spherical) electrostatic shock waves in a dusty plasma system that consists of arbitarily charged dust particles, negatively charged heavy ions following Cairn’s distribution, positively charged ions with two different temperatures, and nonextensive electrons. The reductive perturbation technique is used to derive a modified Burgers equation analytically. Analytical analysis shows that the characteristics of the nonplanar shock waves, including their polarity, amplitude, width, and phase speed, undergo significant alterations due to factors such as the charges on dust particles, the number density of particles, the temperatures of heavy and light ions, nonextensive electron behavior, and dust kinematic viscosity. Furthermore, this study found shock structures with either a positive or negative potential, depending on the critical value of the proportion of ions to the density of dust particles. The findings maybe useful in understanding the characteristics of shock waves both in space plasma environments and laboratory plasmas.
Critical current in a two-dimensional non-magnetically insulated crossed-field gap with monoenergetic emission
Authors: Zhu Xiaojun , Wright Jack K. , Harsha N. R. Sree , Garner Allen L.
Published: July 2024

Prior studies have developed theories for the maximum permissible current, or critical current, for one-dimensional planar and cylindrical crossed-field diodes where the magnetic field is below the Hull cutoff, meaning that an electron emitted from the cathode reaches the anode. Here, we develop semi-empirical and analytical models to predict the critical current for a two-dimensional (2D) planar diode with nonzero monoenergetic initial velocity. The semi-empirical method considers the geometry, nonzero initial velocity, and magnetic field as multiplicative corrections to the Child–Langmuir law for space-charge limited current in a one-dimensional planar diode with an initial velocity of zero. These results agree well with 2D particle-in-cell (PIC) simulations using the over-injection method to assess virtual cathode formation for different emission widths, magnetic field strengths, and initial velocities. The analytical solution agrees better with PIC results because it accounts for the coupling of the magnetic field, geometry, and initial velocity that the semi-empirical approach does not.
Magnetic field enhanced critical current in Ge–Si nanowire Josephson junctions
Authors: Wu Zhen , Ridderbos Joost , Li Ang , Golubov Alexander A. , Zwanenburg Floris A. , Bakkers Erik P. A. M. , Brinkman Alexander , Li Chuan
Published: July 2024

Anomalous critical current enhancement was observed with increasing magnetic field in Josephson junctions based on Ge–Si core-shell nanowires. Despite the predicted topological properties of these nanowires, which could potentially lead to non-trivial superconducting order parameter symmetries, our investigation unveils a more generalized, non-topological explanation for the observed critical current enhancement in these devices. Our findings suggest that the enhancement arises from a thermalization process induced by the magnetic field, wherein in-gap quasiparticles are generated. These quasiparticles play a crucial role in enhancing the cooling of the device, thereby lowering the effective temperature and resulting in an increased critical current. Furthermore, we elucidate how this thermalization effect varies with device geometry and measurement configuration.
Phase jumps in Josephson junctions with time-dependent spin–orbit coupling
Authors: Monroe David , Shen Chenghao , Tringali Dario , Alidoust Mohammad , Zhou Tong , Žutić Igor
Published: July 2024

Planar Josephson junctions (JJs), based on common superconductors and III–V semiconductors, are sought for Majorana states and fault-tolerant quantum computing. However, with gate-tunable spin–orbit coupling (SOC), we show that the range of potential applications of such JJs becomes much broader. The time-dependent SOC offers unexplored mechanisms for switching JJs, accompanied by the 2π-phase jumps and the voltage pulses corresponding to the single-flux-quantum transitions, key to high-speed and low-power superconducting electronics. In a constant applied magnetic field, with Rashba and Dresselhaus SOC, anharmonic current-phase relations, calculated microscopically in these JJs, yield a nonreciprocal transport and superconducting diode effect. Together with the time-dependent SOC, this allows us to identify a switching mechanism at no applied current bias, which supports fractional-flux-quantum superconducting circuits and neuromorphic computing.
Analyzing surface acoustic wave characteristics through first-principles computational methods
Authors: Nakaoka Hironori
Published: July 2024

Surface acoustic wave (SAW) characteristics were analyzed through first-principles calculations utilizing density functional theory. This study computed and compared the elastic constants, piezoelectric constants, dielectric constants, and densities of LiTaO3 and LiNbO3, which are standard materials for SAW filters, against empirical values. The velocities of SAWs and the electromechanical coupling coefficients for both Rayleigh and leaky waves were also determined, demonstrating the method’s sufficient precision for assessing SAW attributes. In addition, this approach was extended to the nitride perovskite LaWN3, evaluating its SAW characteristics. LaWN3 is projected to exhibit an electromechanical coupling coefficient comparable to that of LiTaO3 and LiNbO3, indicating its potential as a novel material for SAW filter applications.
Data acquisition system for a newly-built hard x-ray/soft gamma-ray spectrometer imaging system on experimental advanced superconducting tokamak
Authors: Ma C. , Li E. , Hu Y.
Published: July 2024

A portable hard X-ray and soft gamma-ray spectrometer imaging system (HXS) has been constructed to gather physical information about fast electrons confined in the Experimental Advanced Superconducting Tokamak (EAST). The system is installed on the low field side of the mid-plane and provides a viewing field tangential to the toroidal field. The system utilizes a two-dimensional Cadmium Zinc Telluride (CdZnTe) semiconductor detector with 128 channels, and a data acquisition (DAQ) system has been designed for it. The DAQ system features a highly integrated signal processing system with the capability of high-speed processing and digital transmission of signals from 128 channels. In addition, a related DAQ software has been developed using a modular design approach, facilitating tasks such as data reception, storage, and preliminary processing. HXS, which has been applied during the recent EAST campaign, directly obtains the digital energy spectrum of incident photons. The DAQ system is described in detail in this paper. The hardware components and energy calibration have also been described. Experimental data have been successfully obtained and briefly discussed. More physical research will be reported in future publications.
Theoretical considerations of the volume penalization immersed boundary method for turbulent flows
Authors: Llorente Víctor J.
Published: July 2024

This Letter explores the volume penalization immersed boundary method for turbulent flows from a more physical perspective. The volume penalization approach consists of introducing a penalty source into the governing equations, resulting in a flow akin to a porous medium with low permeability. Although penalizing the turbulent equations conventionally involves adding a similar penalty source as in the original equations, this work reveals an alternative formulation that includes an additional term with physical meaning. The novelty of this Letter is to consider the penalized flow with an additional property, the fluid resistance, establishing a cross correlation with fluctuating velocity for further modeling.
Integrating classical and fractional calculus rheological models in developing hydroxyapatite-enhanced hydrogels
Authors: Cambeses-Franco Paula , Rial Ramón , Ruso Juan M.
Published: July 2024

This study presents a novel method for comprehending the rheological behavior of biomaterials utilized in bone regeneration. The focus is on gelatin, alginate, and hydroxyapatite nanoparticle composites to enhance their mechanical properties and osteoconductive potential. Traditional rheological models are insufficient for accurately characterizing the behavior of these composites due to their complexity and heterogeneity. To address this issue, we utilized fractional calculus rheological models, such as the Scott-Blair, Fractional Kelvin-Voigt, Fractional Maxwell, and Fractional Kelvin-Zener models, to accurately represent the viscoelastic properties of the hydrogels. Our findings demonstrate that the fractional calculus approach is superior to classical models in describing the intricate, time-dependent behaviors of the hydrogel-hydroxyapatite composites. Furthermore, the addition of hydroxyapatite not only improves the mechanical strength of hydrogels but also enhances their bioactivity. These findings demonstrate the potential of these composites in bone tissue engineering applications. The study highlights the usefulness of fractional calculus in biomaterials science, providing new insights into the design and optimization of hydrogel-based scaffolds for regenerative medicine.
Memory-induced absolute negative mobility
Authors: Wiśniewski M. , Spiechowicz J.
Published: July 2024

Non-Markovian systems form a broad area of physics that remains greatly unexplored despite years of intensive investigations. The spotlight is on memory as a source of effects that are absent in their Markovian counterparts. In this work, we dive into this problem and analyze a driven Brownian particle moving in a spatially periodic potential and exposed to correlated thermal noise. We show that the absolute negative mobility effect, in which the net movement of the particle is in the direction opposite to the average force acting on it, may be induced by the memory of the setup. To explain the origin of this phenomenon, we resort to the recently developed effective mass approach to dynamics of non-Markovian systems.
Effects of blowing ratio and film hole arrangement on cavity blade tip cooling
Authors: Jiang Dongpo , Chen Yingjie , Cai Le , Du Zhengshuai , Wang Songtao , Khoo Boo Cheong
Published: July 2024

Blade tip leakage is responsible for reducing the aerodynamic performance and increasing the thermal load. In order to obtain better cooling efficiency, the thermodynamic performance of different film hole arrangements and blowing ratios have been compared and analyzed in a cavity tip structure. Reynolds-averaged Navier–Stokes equation simulations at five blowing ratios from 0.25 to 2.0 have been carried out for three stream-wise and four pitch-wise film hole arrangements. Based on the reference flow field of the cavity without any coolant, the mechanism of the cooling air influence is analyzed by investigating the flow structure and the vortex development in the tip region. It is found that in the stream-wise arrangements and pitch-wise arrangements, the scheme SW1, in which the film holes are arranged along the suction surface, and the scheme PW2, in which the air film holes are arranged at 0.2 times the axial position, provide the maximum average film cooling efficiency of 0.235 and 0.282, respectively. However, the effective cooling area of SW1 is greater than that of PW2, which are 39.2% and 41.3%, respectively. At the lower blowing ratios, the cooling efficiency increases with the increase in the blowing ratio; however, at the higher blowing ratios, the cooling effect is affected by the clearance size and cavity depth when the coolant impinges on the casing wall.
Long carbon–carbon bonds and beyond
Authors: Kishimoto Masaya , Kubo Takashi
Published: July 2024

Advances in synthetic organic chemistry have facilitated the preparation and exploration of compounds exhibiting unusual bonding states. This review delves into carbon–carbon single bonds that are exceeding typical length of bonds, elucidating recent advances in understanding their bonding nature, properties, and chemical reactivity. Additionally, we examine factors contributing to the occurrence of such elongated bonds and their effects on other bonding parameters. Furthermore, we shift our focus toward the π-dimers of radical species, surpassing the limit of two-center two-electron (2c/2e) bonds, discussing their formation mechanisms, stability, and inherent properties. A key feature in the electronic structure of π-dimers is the bonding interaction of two unpaired electrons spanning multiple atoms, that is, multicenter two-electron (mc/2e) bonding. This review sheds light on the significant role played by extended carbon–carbon bonds (2c/2e bonds) and radical π-dimers (mc/2e bonding) in organic chemistry, providing valuable insight for future research on new functional materials.
High-temperature setup for infrared reflection spectroscopy
Authors: Steigleder Marc , Dressel Martin
Published: July 2024

We have designed an oven for optical reflection measurements at temperatures as high as 1000 K. The compact setup can be attached to any Fourier-transform infrared spectrometer using a microscope. The details of the layout, operation, and performance are discussed as well as ways for reference measurements and data correction. Finally, the high-temperature setup is utilized to determine the infrared reflectivity of tungsten up to T = 1000 K, which can serve as a reference mirror for future experiments.
Modeling of collision-induced excitation and quenching of atomic nitrogen
Authors: Wu Yanze , Hochlaf Majdi , Schatz George C.
Published: July 2024

Excited atomic nitrogen atoms play an important role in plasma formation in hypersonic shock-waves, as happens during spacecraft reentry and other high velocity vehicle applications. In this study, we have thoroughly studied collision induced excitation associated with two colliding nitrogen atoms in the N(4S), N(2D), and N(2P) states at collision energies up to 6 eV, using time-independent scattering calculations to determine cross sections and temperature-dependent rate coefficients. The calculations are based on potential curves and couplings determined in earlier multireference configuration interaction calculations with large basis sets, and the results are in good agreement with experiments where comparisons are possible. To properly consider the spin–orbit coupling matrix, we have developed a scaling method for treating transitions between different fine-structure components that only require calculations with two coupled states, and with this, we define accurate degeneracy factors for determining cross sections and rate coefficients that include all states. The results indicate that both spin–orbit and derivative coupling effects can play important roles in collisional excitation and quenching, and that although derivative coupling is always much stronger than spin–orbit, there are many transitions where only spin–orbit can contribute. As part of this, we identify two distinct pathways associated with N(2P) relaxation and one Auger-like mechanism leading to two N(2D) that could be important at high temperatures.
Solution of the structure of the high-coverage CO layer on the Ru(0001) surface—A combined study by density functional theory and scanning tunneling microscopy
Authors: Illner Hannah , Sakong Sung , Groß Axel , Wintterlin Joost
Published: July 2024

Structures formed by dense CO adsorption layers can provide information about the balance between molecule–surface and molecule–molecule interactions. However, in many cases, the structure models are not clear. Using density functional theory (DFT) and scanning tunneling microscopy (STM), we have investigated the high-coverage CO layer on the Ru(0001) surface. Previous investigations by low-energy electron diffraction (LEED) and vibrational spectroscopy led to conflicting results about the structure. In the present study, 88 models with coverages between 0.58 and 0.77 monolayers have been analyzed by DFT. The most stable structures consist of small, compact CO clusters with an internal pseudo 1×1 structure. The CO molecules in the cluster centers occupy on-top sites in an upright position, whereas the molecules farther outside are slightly shifted from these sites and tilted outward. STM data of the CO-saturated surface at low temperatures, corresponding to a coverage of 0.66 monolayers, show a quasi-hexagonal pattern of features with an internal hexagonal fine structure. Simulated images based on the cluster model agree with the experimental data. It is concluded that the high-coverage CO layer consists of the close-packed clusters predicted by DFT as the most stable structure elements. In the experiment, the sizes and shapes of the clusters vary. However, the arrangement is not random but follows defined tiling rules. The structure remains ordered, almost up to room temperature. The LEED data are re-interpreted on the basis of the Fourier transforms of the STM data, solving the long-standing conflict about the structure.
Numerical investigation of cylinder rotors with various endplates
Authors: Liu Jianhan , Ma Wenyong , Zheng Deqian , Jin Longqian , Liu Qi
Published: July 2024

For a finite-length cylinder rotor, rotation induces unique pattern tip vortices at the free end, significantly altering the aerodynamic characteristics of the rotor. Endplates are often applied to finite-length cylinders as a means of restraining end effects. The endplates change the aerodynamic characteristics of the rotor by affecting the end axial flow. In the present study, cylinder rotors with static and rotating endplates of various diameters are investigated by means of large eddy simulation. By analyzing the aerodynamic force, wind pressure, and flow field characteristics of the rotors, the varying patterns and reasons for the aerodynamic characteristics of rotors with static and rotating endplates are clarified. The results show that the endplate induces disk vortices and changes the vortex patterns at the free end of the rotor, and the static endplates show little effect on the development of tip vortices, so the wake vortices show the triple vortex pattern, whereas the rotating endplates enhance the intensity of the plate vortices and inhibit the tip vortices development, leading to the double vortex pattern, which in turn produces a different pattern of aerodynamic characteristics compared to the rotor with the static endplates. The mechanism of the variation in the aerodynamic characteristics and vortex patterns is partially explained by analyzing and discussing the flow field results.
Carbon-doped ZnO thin films: A transparent conductive oxide for application in solar-blind photodetectors
Authors: Ye Lijuan , Yu Jianhao , Zhang Hong , Li Honglin , Pang Di , Tang Yan , Kong Chunyang , Fang Liang , Ruan Haibo , Li Wanjun
Published: July 2024

Transparent conductive oxide (TCO) films are crucial in optoelectronic devices, such as photodetectors, due to their unique blend of transparency and electrical conductivity. ZnO is a top choice for TCOs owing to its excellent properties, non-toxicity, and cost-effectiveness. In this work, we explore the potential of carbon doping to enhance the electrical properties of ZnO films for transparent conductive applications. Our findings reveal that C-doped ZnO (ZnO:C) films retain the pristine high quality and surface morphology despite an increase in defects with higher C doping. Notably, C doping does not compromise the visible light transmittance of ZnO films, while inducing a gradual increase in optical bandgap, indicative of the typical Burstein–Moss effect. As carbon doping increases, the ZnO:C films exhibit improved carrier concentration, lower resistivity, and sustained high mobility, achieving optimal performance with an electron concentration of 3.73 × 1019 cm−3, resistivity of 3.69 × 10−3 Ω cm, and mobility of 46.08 cm2 V−1 s−1. Finally, we utilized ZnO:C films as a transparent electrode material in ε-Ga2O3-based photodetector, achieving the development of transparent device and attaining high-performance solar-blind detection capabilities. This work provides a strategy for developing a transparent conductive oxide, with ZnO:C emerging as a promising rival to IIIA-doped ZnO for optoelectronic applications.
Extending non-adiabatic rate theory to strong electronic couplings in the Marcus inverted regime
Authors: Fay Thomas P.
Published: July 2024

Electron transfer reactions play an essential role in many chemical and biological processes. Fermi’s golden rule (GR), which assumes that the coupling between electronic states is small, has formed the foundation of electron transfer rate theory; however, in short range electron/energy transfer reactions, this coupling can become very large, and, therefore, Fermi’s GR fails to make even qualitatively accurate rate predictions. In this paper, I present a simple modified GR theory to describe electron transfer in the Marcus inverted regime at arbitrarily large electronic coupling strengths. This theory is based on an optimal global rotation of the diabatic states, which makes it compatible with existing methods for calculating GR rates that can account for nuclear quantum effects with anharmonic potentials. Furthermore, the optimal GR (OGR) theory can also be combined with analytic theories for non-adiabatic rates, such as Marcus theory and Marcus–Levich–Jortner theory, offering clear physical insights into strong electronic coupling effects in non-adiabatic processes. OGR theory is also tested on a large set of spin-boson models and an anharmonic model against exact quantum dynamics calculations, where it performs well, correctly predicting rate turnover at large coupling strengths. Finally, an example application to a boron-dipyrromethane–anthracene photosensitizer reveals that strong coupling effects inhibit excited state charge recombination in this system, reducing the rate of this process by a factor of 4. Overall, OGR theory offers a new approach to calculating electron transfer rates at strong couplings, offering new physical insights into a range of non-adiabatic processes.
Formation dynamics of the satellite droplet in the breakup of a symmetrical liquid bridge
Authors: Wang Kaibo , Li Dege , Xie Jianuo , Ni Ganggang , Li Zihao , Sun Qiang , Zhang Yanzhen , Wei Xiaofeng
Published: July 2024

Inkjet printing technology has played an irreplaceable role in life science, precision manufacturing, and other frontier fields in recent years. However, the further development of this technology is limited by the fact that its printing resolution is difficult to raise to a higher level. The emerging satellite droplet printing technology offers a new approach for inkjet printing to break through the bottleneck of printing resolution limitations. In this paper, a symmetrical satellite droplet printing strategy is proposed. The effects of the geometric parameters of the satellite droplet generating device, the physical properties of the ink, and the operating parameters on the liquid bridge breakup process and the size of the satellite droplet are systematically studied. The phase field method and adaptive mesh refinement strategy are applied to solve the two-dimensional symmetrical model. The results indicate that the length of the liquid bridge, the radius of the bridge, the viscosity of the ink, and the drainage velocity are all positively correlated with the satellite droplet size, while the surface tension coefficient has a negative correlation with the satellite droplet size. Furthermore, the three-phase contact line at the orifice end will slip toward the center if the initial radius of the liquid bridge is quite large. Based on these investigations and discussions, a corresponding effective working space for satellite droplet printing is obtained, which lays the foundation for the popularization and further development of satellite droplet printing technology.
Visualizing the degradation of fibrin fibers
Authors: Risman Rebecca A. , Tutwiler Valerie
Published: July 2024

Polymeric fibrin provides the structural and mechanical stability of a blood clot. Fibrin fibers are rod-like and create a network mesh that holds blood cells. When a clot has performed its physiological function in wound healing and preventing excessive blood loss, it must be resolved by the enzymatic degradation of fibrin, otherwise known as fibrinolysis. If a blood clot forms when or where it is not needed, as occurs in ischemic strokes and myocardial infarctions, the blood clot (thrombus) can obstruct blood flow to downstream organs. Obstructive thrombi must be degraded or removed to prevent further complications. If a clot is not degraded on its own, lytic agents (i.e., tissue plasminogen activator, tPA) are given exogenously to induce fibrinolysis. Here, we fluorescently labeled both fibrin and tPA to visualize degradation at the edge of the clot. The fibers with bound tPA were looped or coiled while the fibers farther into the clot remain straight and stable displaying the diffusion of tPA and depth of lysis. This image provides (1) a new method to monitor fibrinolysis with a commercially available chamber with convenient inlets and (2) the visualization of tPA-bound fibrin and the behavior of fibers during degradation. Future work could utilize this technique to study tPA molecule and fibrin interactions, lysis front degradation, and fibrin fiber linearity to understand the mechanisms of intermolecular dynamics dependent on network structure. An enhanced insight into this process can aid in the development of optimized therapeutics to target stubborn clots.