bluuebunny/crossref_metadata_2025 huggingface dataset:
A spectral condition for component factors in graphs
Authors: Wang Sufang , Zhang Wei
Published: June 2024

LetGbe a graph. A {K1,2,K1,3,K5}-factor ofGis a spanning subgraph ofG, in which every component is isomorphic to a member of {K1,2,K1,3,K5}. In this paper, we establish a lower bound on the spectral radius ofGto ensure thatGcontains a {K1,2,K1,3,K5}-factor.
Systematic Reviews on the Prevention of Adverse Pregnancy Outcomes Related to Maternal Obesity to Improve Evidence-Based Counselling
Authors: Behnam Susann , Arabin Birgit
Published: June 2024

Health professionals and their patients should understand the importance of evidence. In the case of gestational diabetes mellitus, which is often associated with an abnormally high body mass index, the immediate and long-term outcome of women and their offspring depends in part on advice and implementation of lifestyle changes before, during and after pregnancy.

Up to September 2023, MEDLINE, CENTRAL, and WEB OF SCIENCE were used to identify systematic reviews and meta-analyses on the prevention of gestational diabetes. The ROBIS and AMSTAR criteria were analyzed for all systematic reviews.

A total of 36 systematic reviews were identified. Dietary interventions, physical activity or a combined approach all reduced adverse pregnancy outcomes such as gestational diabetes, pregnancy-induced hypertension and related morbidities. Within the randomized controlled trials included in the 36 systematic reviews, the type, intensity and frequency of interventions varied widely. The primary outcomes, reporting and methodological quality of the 36 systematic reviews and meta-analyses also varied.

The meta-analysis with the highest ROBIS and AMSTAR-2 scores was selected to design an icon array based on a fact box simulating 100 patients.

We propose a methodology for selecting the best evidence and transforming it into a format that illustrates the benefits and harms in a way that can be understood by lay patients, even if they cannot read. This model can be applied to counselling for expectant mothers in low and high-income countries, regardless of socioeconomic status, provided that women have access to appropriately trained healthcare providers.
Ni(OTf)2-Catalyzed Michael Addition Reactions of 4-Hydroxycoumarins to α,β-Unsaturated 2-Acyl Imidazoles
Authors: Wang Honghong , Gong Fan , Gong Jun , Xue Ping , Lu Helin , Wang Xiaobo
Published: June 2024

An eﬃcient Michael addition of 4-hydroxycoumarins to α,β-unsaturated 2-acyl imidazoles catalyzed by Ni(OTf)2 as a Lewis acid has been developed. A series of 4-hydroxycoumarin derivatives were obtained in excellent yields (up to 96%) with a 2 mol% catalyst loading under mild conditions. Additionally, when a chiral-at-metal rhodium complex was used as the catalyst, moderate enantioselectivity was observed (74% ee).
Construction and Validation of a Prognostic Model Based on
Mitochondrial Genes in Prostate Cancer
Authors: Wang Dan , Pan Hui , Cheng Shaoping , Huang Zhigang , Shi Zhenlei , Deng Hao , Yang Junwu , Jin Chenghua , Dai Jin
Published: June 2024

This study attempted to build a prostate cancer (PC) prognostic risk model with
mitochondrial feature genes. PC-related MTGs were screened for Cox regression
analyses, followed by establishing a prognostic model. Model validity was
analyzed via survival analysis and receiver operating characteristic (ROC)
curves, and model accuracy was validated in the GEO dataset. Combining risk
score with clinical factors, the independence of the risk score was verified by
using Cox analysis, followed by generating a nomogram. The Gleason score,
microsatellite instability (MSI), immune microenvironment, and tumor mutation
burden were analyzed in two risk groups. Finally, the prognostic feature genes
were verified through a q-PCR test. Ten PC-associated MTGs were screened, and a
prognostic model was built. Survival analysis and ROC curves illustrated that
the model was a good predictor for the risk of PC. Cox regression analysis
revealed that risk score acted as an independent prognostic factor. The Gleason
score and MSI in the high-risk group were substantially higher than in the
low-risk group. Levels of ESTIMATE Score, Immune Score, Stromal Score, immune
cells, immune function, immune checkpoint, and immunopheno score of partial
immune checkpoints in the high-risk group were significantly lower than in the
low-risk group. Genes with the highest mutation frequencies in the two groups
were SPOP, TTN, and TP53. The q-PCR results of the feature genes were consistent
with the gene expression results in the database. The 10-gene model based on
MTGs could accurately predict the prognosis of PC patients and their responses
to immunotherapy.
Long-Term Clinical Outcome of Medial Shoulder Instability in a Dog Treated with Synthetic Implant, Cortical Button, and Interference Screw
Authors: Letesson Julien , Crumière Antonin , Goin Bastien
Published: June 2024

Objective The objective of this study was to describe the surgical procedure and long-term outcome of traumatic medial shoulder instability in one dog treated with an ultra-high molecular weight polyethylene implant.

A Fox Terrier had traumatic medial shoulder instability caused by the disruption of the subscapularis muscle and medial glenohumeral ligament. The joint was stabilized through a medial approach with an ultra-high molecular weight polyethylene implant secured on the glenoid by a cortical button and on the humerus by an interference screw. Postoperative and follow-up examinations were performed at 1, 2, 4.5 months, and 2.5 years.

Results The patient bore weight after surgery and resumed normal gait after 2 months. Both the scapular and humeral tunnels had widened, essentially at their medial entrance, at 1 month postoperatively.

Entrance diameter increased for 2 months and remained unchanged thereafter. An increase of 35 degrees in the abduction angle was observed in the long term at the 2.5-year control with minor osteoarthritis. No implant loosening, medial laxity, excessive abduction angle, inflammation, or septic reaction were observed.

Conclusion The treatment of this case resulted in a satisfactory clinical outcome despite tunnel widening. This modified method using an interference screw could thus be considered as an alternative treatment of medial shoulder instability.
Radial Head and Neck Ostectomy Maintained Elbow Joint Function in a Labrador Retriever with Type 1 Congenital Elbow Luxation
Authors: Pankowski Anne , McCarthy Jessica
Published: June 2024

A 6-month-old Labrador Retriever was diagnosed with a Type 1 caudolateral congenital right elbow luxation. A radial head and neck ostectomy was performed with no surgical attempt to further stabilize the elbow joint. One year after surgery, objective gait analysis showed only a mild asymmetry in peak vertical forces. Pre- and postoperative Liverpool Osteoarthritis in Dogs scores showed a decrease in perceived pain and a reduction in signs of osteoarthritis. In dogs with congenital radial head luxation, a radial head and neck ostectomy without surgical joint stabilization may be a viable, simple option for a one-time intervention that can reduce pain and signs of secondary osteoarthritis and improve limb function.
The relationship between childhood trauma and cyberbullying: a meta-analysis of mainland Chinese adolescents and young adults
Authors: Li Shunyu , Ainiwaer Kelare , Zhang Yuxuan
Published: June 2024

In recent years, scholars have extensively investigated the correlation between childhood trauma and cyberbullying. However, findings in this area have been inconsistent. The current study employed a meta-analysis method to explore the relationship between childhood trauma and cyberbullying among students in mainland China, aiming to establish a reliable foundation for resolving existing controversies on this matter. This study included 26 articles, encompassing a total of 29,389 subjects. The findings revealed a moderate positive correlation between childhood trauma and cyberbullying (r = 0.418, 95%CI [0.335, 0.495]). Firstly, the correlation was affected by regions. Compared with eastern China, cyberbullying in the central and western regions was more likely to be affected by childhood trauma (rEastern < rCenter < rWestern). Secondly, the childhood trauma scale could moderate this correlation (rCPANS < rCPMSs < rCTQ-SF), showing the highest correlation coefficient when the CTQ-SF was used as a tool to measure childhood trauma. Thirdly, age also significantly influenced the relationship between childhood trauma and cyberbullying. The correlation coefficient among young adults was higher than that of adolescents (rAdolescents < rYoung adults). Lastly, gender differences were found to significantly moderate the relationship between childhood trauma and cyberbullying, indicating a higher correlation coefficient in female than male (P < 0.05).
Does dispositional awe promote customer citizenship behaviours? The multiple mediating effects of construal level and social connectedness
Authors: Zhang Zheng , Li Xuexin
Published: June 2024

In the digital economy, the relationship between customers and companies is a win-win cooperation, and value co-creation has become the mainstream business development concept. Against this background, customer citizenship behaviours have received increasing and widespread attention in marketing and consumer behaviour research. However, previous studies have not sufficiently considered the importance of trait emotions in predicting customer citizenship behaviours. By focusing on a specific emotional disposition with positive functions, dispositional awe, this study develops an integrative model based on the prototype model of awe and the elaborated model of awe’s prosocial effects. This model examines the impact of dispositional awe on customer citizenship behaviours and analyses the roles of construal level and social connectedness in it. Drawing on a sample of 701 questionnaires from Chinese adults and using structural equation modelling, this study finds that dispositional awe contributes positively to three types of customer citizenship behaviours: making recommendations, helping other customers, and providing feedback. In addition, dispositional awe can influence customer citizenship behaviours through the independent mediating effect of social connectedness as well as the serial mediating effect of construal level and social connectedness. These findings suggest that frequent experiences of awe help develop an individual’s internal abstract mindset and subjective sense of connection to external society, thereby motivating customer citizenship behaviours. This study provides valuable insights into whether and how dispositional awe can influence customer citizenship behaviours and offers operational strategies for marketing practice.
One-step synthesis of B and N co-doped carbon nanotubes for high-stability lithium-ion batteries
Authors: Huan Huan , Chengxiang Tian , Shuangyue Wang , Qingyi Feng , Hongxiang Deng , Xia Xiang , Xiaotao Zu
Published: June 2024

Creating adsorption sites by doping heteroatoms into the graphitic structures of carbon electrodes is an effective strategy for improving lithium storage in lithium-ion batteries. In this work, we prepared carbon nanotubes with controllable morphology and controllable nitrogen-doping level by a one-step pyrolysis method through adjusting the amount of urea used during synthesis. Under the synergistic effects of high temperature and Ni-catalyst migration, the carbon nanosheets generated by pyrolysis become coiled into tube-like structures. Characterization using Raman and x-ray photoelectron spectroscopy revealed that the B and N atoms were successfully co-doped into the resultant carbon nanotubes. When the obtained materials were used as lithium-ion battery anodes, reversible specific capacities of 337.11 and 187.62 mA h g−1 were achieved at current densities of 100 and 2000 mA g−1, respectively. Moreover, a capacity of 140.53 mA h g−1 was retained after 2000 cycles at a current density of 2000 mA g−1. The mechanism of lithium storage in these carbon materials was elucidated using cyclic voltammetry tests. Regarding other functional applications, the synthesized composite carbon nanotube material could also be used in other energy-storage battery systems, such as in the sulfur-carrying structures of lithium-sulfur batteries and in the three-dimensional porous structures of sodium batteries.
A Laguerre–Volterra network model based on ant colony optimization applied to evaluate EMG-force relationship in the muscle fatigue state
Authors: Ma Min , Luo Xi , Xiahou Shiji , Shan Xinran
Published: June 2024

With the accuracy and convenience improvement of electromyographic (EMG) acquired by wearable devices, EMG is gradually used to evaluate muscle force signal, a non-invasive evaluation method. However, the relationship between EMG and force is a complex nonlinear relationship, even which will change with different movements and different muscle states. Therefore, it is difficult to evaluate this nonlinear EMG–force relationship, especially when the muscle state gradually transits from non-fatigue to deep fatigue. For more accurate values of force in human fatigue state, this paper proposes a dual-input Laguerre–Volterra network (LVN) model based on ant colony optimization. First, the changes in 19 EMG features are discussed with increasing fatigue. We also consider two non-Gaussian features: kurtosis and negentropy in the 19 features. Later, 11 EMG fatigue features are picked out according to the fatigue test. Then, the preprocessed EMG and a composite signal of the 11 fatigue features are simultaneously input into the LVN model. Subsequently, the ant colony optimization algorithm is selected to train the model parameters. At the same time, a penalty term that we defined is introduced into the model cost function to adjust the weight of each feature adaptively. Finally, some experiments prove that the LVN model could quick fit the accurate force signal in five fatigue stages, such as non-fatigue, slight fatigue, mild fatigue, severe fatigue, and extreme fatigue. This LVN model can quickly transform EMG into strength signal in real time, which is suitable for people to observe muscle strength by a wearable device and makes it easy to detect the muscle current state. This model has good stability and can remain effective for a long time with training once, which provides convenience for the users of wearable devices.
Constructing coarse-grained models with physics-guided Gaussian process regression
Authors: Fang Yating , Zhao Qian Qian , Sills Ryan B. , Ezzat Ahmed Aziz
Published: June 2024

Coarse-grained models describe the macroscopic mean response of a process at large scales, which derives from stochastic processes at small scales. Common examples include accounting for velocity fluctuations in a turbulent fluid flow model and cloud evolution in climate models. Most existing techniques for constructing coarse-grained models feature ill-defined parameters whose values are arbitrarily chosen (e.g., a window size), are narrow in their applicability (e.g., only applicable to time series or spatial data), or cannot readily incorporate physics information. Here, we introduce the concept of physics-guided Gaussian process regression as a machine-learning-based coarse-graining technique that is broadly applicable and amenable to input from known physics-based relationships. Using a pair of case studies derived from molecular dynamics simulations, we demonstrate the attractive properties and superior performance of physics-guided Gaussian processes for coarse-graining relative to prevalent benchmarks. The key advantage of Gaussian-process-based coarse-graining is its ability to seamlessly integrate data-driven and physics-based information.
Ultra-low threshold pH sensor based on a whispering gallery mode microbubble resonator
Authors: Cao Yue , Dai Jin , Peng Xu-Biao , Ma Ji-Yang , Zhao Qing
Published: June 2024

Laser sensing has a wide range of applications. In this paper, we propose a pH sensing laser with an ultra-low threshold and low sample consumption based on a whispering-gallery-mode microbubble resonator. Rhodamine 6G aqueous solutions with different pH values are injected through microfluidic channels as the lasing gain media and interact with a high-quality factor microbubble cavity with a sample consumption of only 550 pL to achieve lasing. Subtle pH changes of the aqueous solution lead to changes in lasing intensity in real time, and the threshold reaches a minimum of 0.091 μ J/mm2. The low pump energy density effectively avoids the self-aggregation and photobleaching effects of dye molecules present in high-concentration rhodamine 6G solutions. The lasing characteristics under different pH conditions were determined experimentally and theoretically, and the results are in good agreement. Due to the deprotonation of amino groups in highly alkaline environments, the lasing threshold is highly dependent on the pH of rhodamine 6G aqueous solutions. In the pH range of 10.16–13.14, the lasing intensity changes considerably with the increasing pH. The proposed pH-sensing laser exhibits a fast response time, low toxicity, and a high signal-to-noise ratio, making it promising for highly sensitive alkaline detection in biological applications.
The impact of collisionality on the runaway electron avalanche during a tokamak disruption
Authors: Arnaud Jonathan S. , McDevitt Christopher J.
Published: June 2024

The exponential growth (avalanching) of runaway electrons (REs) during a tokamak disruption continues to be a large uncertainty in RE modeling. The present work investigates the impact of tokamak geometry on the efficiency of the avalanche mechanism across a broad range of disruption scenarios. It is found that the parameter ν*,crit, describing the collisionality at the critical energy to run away, delineates how toroidal geometry impacts RE formation. In particular, utilizing a reduced but self-consistent description of plasma power balance, it is shown that for a high-density deuterium-dominated plasma, ν*,crit is robustly less than one, resulting in a substantial decrease in the efficiency of the RE avalanche compared to predictions from slab geometry. In contrast, for plasmas containing a substantial quantity of neon or argon, ν*,crit≳1, no reduction of the avalanche is observed due to toroidal geometry. This sharp contrast in the impact of low- vs high-Z material results primarily from the relatively strong radiative cooling from high-Z impurities, enabling the plasma to be radiatively pinned at low temperatures and thus large electric fields, even for modest quantities of high-Z material.
Role of solid solution strengthening on shock wave compression of [111] copper crystals
Authors: Bryukhanov I. A. , Chaikovskii D.
Published: June 2024

The paper investigates the role of solid solution strengthening on the shock wave structure and Hugoniot elastic limit (HEL) in [111] copper crystals by molecular dynamics. Cu–Ni, Cu–Zn, Cu–Ag, and Cu–Al solid solutions are chosen to cover the range of atomic size misfit parameters for the solute atoms. The results show that in crystals with dislocations, the HEL decays slower with an increase in the misfit parameter of the solute, resulting in higher HEL values at a certain shock propagation distance. The Cu–Al solid solutions with the largest misfit parameter exhibit the largest deceleration of HEL decay. When the concentration of Al atoms increases to 20 at. %, the HEL almost does not change with shock propagation distance and a plateau shape of the elastic precursor is observed, as in the case of perfect crystals. In solid solutions without dislocations, the elastic precursor forms at lower velocities compared with perfect copper crystals, except for the Cu–20 at. % Ni solid solution. The HEL values increase with increasing misfit parameters and may take values lower than that for pure copper. These results show that the formation of the elastic precursor is facilitated by the presence of solid solution atoms, but the HEL magnitude and decay exponent are related to dislocation mobility in [111] copper crystals.
Open-circuit voltage degradation and trap-assisted tunneling in electron and proton-irradiated ultra-thin GaAs solar cells
Authors: Barthel A. , Sato S.-I. , Sayre L. , Li J. , Nakamura T. , Ohshima T. , Imaizumi M. , Hirst L. C.
Published: June 2024

Ultra-thin solar cells display high intrinsic radiation tolerance, making them interesting for space applications. This study investigates the dependence of the open-circuit voltage degradation and overall current–voltage behavior of devices with 80 nm thick GaAs absorber layers, on their absorber layer doping concentration and the radiation type used to introduce damage. The radiation types used were 1 MeV electrons and 20 keV, 100 keV, and 1 MeV protons. It is shown that the open-circuit voltage degradation rate increases with absorber layer doping concentration. This is linked to the increase in trap-assisted tunneling enhancement of the recombination rate, facilitated by the increase in electric field strength in the absorber layer with doping concentration. Trap-assisted tunneling is also found to contribute to the high local ideality factors observed in these devices, exceeding values of 2, and to be responsible for the trend of an increasing ideality factor with doping concentration. The significant role of trap-assisted tunneling in the devices is established through fitting of dark current–voltage data using a custom recombination–generation model. An open-circuit voltage degradation rate and local ideality factor curves are also shown to vary with radiation type, despite accounting for their differences in non-ionizing energy loss. This is corroborated by corresponding trends in carrier lifetime damage constants, extracted from the fitting of the dark current–voltage curves. This suggests that the introduction or behavior of radiation damage differs between ultra-thin and conventional, thicker solar cells, where non-ionizing energy loss theory tends to be reliable, especially over the studied proton energy range.
Phonon spectra of finite dust clusters under a transverse external magnetic field
Authors: Sarma Hirakjyoti , Das Nilakshi
Published: June 2024

The dynamics of two-dimensional dust clusters in plasma environment are studied at different strengths of a transverse external magnetic field, via Langevin dynamics simulation. The collective oscillation spectra obtained from simulation are compared with the dispersion relation derived from the analytical calculation under harmonic approximation. At high magnetic field strength, in the case of a linear chain, a longitudinal optic branch emerges, whereas in the case of a 2D isotropic cluster, two clear distinct branches appear, with the high frequency branch approaching cyclotron frequency. Mean squared displacement is obtained for the 2D cluster as a probe of single particle dynamics at different values of magnetization. At a larger value of coupling parameter, the cluster exhibits a crossover from normal to superdiffusive behavior with the change in the magnetic field strength, which is a result of the competition between the cyclotron and the harmonic time period. However, at a lower value of coupling parameter, the cluster remains subdiffusive at all field strengths. The study brings out several novel features of magnetized dust clusters in complex plasma environments.
Interplay between anisotropic strain, ferroelectric, and antiferromagnetic textures in highly compressed BiFeO3 epitaxial thin films
Authors: Abdelsamie Amr , Chaudron Arthur , Bouzehouane Karim , Dufour Pauline , Finco Aurore , Carrétéro Cécile , Jacques Vincent , Fusil Stéphane , Garcia Vincent
Published: June 2024

Bismuth ferrite (BiFeO3) thin films were epitaxially grown on (110)- and (001)-oriented NdGaO3 single crystal orthorhombic substrates by pulsed laser deposition. The films grown on NdGaO3(110) are fully strained and show two ferroelectric variants that arrange in a stripe domain pattern with 71° domain walls, as revealed by piezoresponse force microscopy. We explored their antiferromagnetic textures using scanning nitrogen-vacancy magnetometry. Surprisingly given the large compressive strain state, the films still show a spin cycloid, resulting in a periodic zig-zag magnetic pattern due to the two ferroelastic variants. The films grown on NdGaO3(001) are also fully strained, but the (001) orthorhombic substrate imposes a strongly anisotropic in-plane strain. As a consequence, the ferroelectric polarization exhibits a uniaxial in-plane component, parallel to the b-axis of the substrate. The ferroelectric domain pattern consists of 109° charged domain walls between the two selected ferroelastic variants. This anisotropic strain impacts the magnetic state of BiFeO3 and leads to a simpler spin texture defined by a single propagation vector for the spin cycloid. In both cases, electric-field control of ferroelectric domains tends to favor a transition to a canted antiferromagnetic order. These results reveal that the cycloidal structure of BiFeO3 can undergo large compressive strain and open further electrical means to tune the magnetic state of this room-temperature multiferroic compound.
Interference patterns of propagating spin wave in spin-Hall oscillator arrays
Authors: Haidar Mohammad
Published: June 2024

In this study, we discuss the observation of spin-wave interference generated by magnetic oscillators. We employ micromagnetic simulations for two coherent spin-Hall nanowire oscillators positioned nearby, horizontally or vertically. The two nanowires produce circular waves with short wavelengths on the order of 100 nm, which interfere with each other. In the horizontal configuration, the spin waves exhibit constructive and destructive fringes, indicating amplification or cancellation of the amplitudes, respectively. The synchronization of spin waves in the current geometry of the two nanowires is facilitated by the combination of dipolar fields and propagating spin waves. Additionally, the vertical alignment results in standing spin waves characterized by multiple antinodes and nodes. These observations are interpreted using a wave model that incorporates the superposition principle for each case.
Analysis of film cooling effectiveness for jet in crossflow with upstream and downstream roughness
Authors: Huang Weichen , Wang Kechen , Li Yaxiong , Chen Wenbin , Zhou Wenwu , Peng Di , Liu Yingzheng
Published: June 2024

Roughness, in various distributions and on various scales, is widely encountered in turbine modules and has a complex modulating effect on the distribution of film cooling effectiveness. In this study, the fast-response pressure-sensitive paint technique was utilized to analyze the steady and unsteady behaviors of film cooling effectiveness under various roughness conditions. Two roughness conditions (upstream roughness and the combination of upstream and downstream roughness) were examined at three roughness scales (ks/D = 0.016, 0.129, and 0.782) and three blowing ratios (M = 0.5, 1.0, and 1.5). Comparisons of the steady behaviors of cooling effectiveness revealed that upstream roughness was the primary factor influencing cooling effectiveness for the adequate film attachment (M = 0.5 and 1.0) and that the cooling effectiveness deteriorated with rising ks/D. Downstream roughness improved the cooling effectiveness in cases with poor film attachment (M = 1.5). Considering that the distribution of film cooling effectiveness is modulated by the vortical structures of jet in crossflow, the unsteady behaviors of roughness-affected cooling effectiveness were analyzed through proper orthogonal decomposition. Upstream roughness influenced the counter-rotating vortex pair and horseshoe vortex (HV) signatures by separately widening and shortening the patterns in the lateral and streamwise directions, a trend that became more pronounced with increasing ks/D values. Moreover, larger roughness scales at lower blowing ratios caused asymmetry in the signatures. Downstream roughness primarily affected the signatures through local morphological variations, inducing oscillations in modal patterns. For attached films, downstream roughness had a nonsignificant impact, while for detached films, disturbances caused by downstream roughness resulted in vague and asymmetric modal patterns. Evaluation of the reconstructed cooling effectiveness revealed that roughness tended to affect the unsteady behavior of HV-modulated cooling effectiveness at high frequencies. These clarified steady and unsteady behaviors across various roughness conditions provide references for improving film-cooling structures to accommodate diversely roughened turbine modules.
High performance molecular iodine optical reference using an unsaturated vapor cell
Authors: Zhang Zhenqi , You Wen , Liu Xingyue , Liu Hongli , Yuan Wenhao , Zhang Jie , Deng Ke , Lu Zehuang
Published: June 2024

We describe a high-performance molecular iodine optical frequency reference that is referenced to the R(56)32-0: a1 hyperfine transition of molecular iodine based on modulation transfer spectroscopy. We design an unsaturated iodine vapor cell with a gas pressure equivalent to the saturation pressure at −17 °C. Using this cell, we developed a compact, frequency-stabilized laser. The iodine cell operates at room temperature and is not actively temperature stabilized. We demonstrate a laser with fractional frequency instability of 1.4 × 10−14 at 1 s and 1.7 × 10−15 at 104 s. To our knowledge, the level of frequency instability at 104 s is comparable to the previously reported best results for an iodine stabilized laser. These results suggest that using an unsaturated iodine vapor cell is a valid approach for the development of long-term, stable iodine-based optical references.
Analysis of droplet vibration dynamics in two-dimensional/three-dimensional flow field of fuel cells
Authors: Guo Shuo , Zhao Youqun , Lin Fen , Li Danyang , Wang Xuanying
Published: June 2024

This study used the two-dimensional fluid volume method to investigate the effect of vibration on the detachment and removal of droplets in the two-dimensional/three-dimensional flow channel of proton exchange membrane fuel cell (PEMFC). The vibration frequency was used as the main variable to study the dynamic process of droplets in the channel, and typical droplet flow modes and separation methods were determined. The water removal ability of the two-dimensional/three-dimensional flow channel under vibration conditions was evaluated using droplet breakage time and coverage rate as evaluation indicators. Finally, the orthogonal table method was used to analyze the effects of vibration frequency, vibration amplitude, wind speed, and droplet size on the water removal ability of the three-dimensional flow field. The results indicate that under vibration conditions, the main motion modes of droplets are rolling mode and crushing mode and that the drainage capacity of the three-dimensional flow field is much higher than that of the two-dimensional flow field in both modes. The impact of vibration on the removal of droplets in the flow channel in the crushing mode is more significant compared to the rolling mode, and the vibration frequency has a greater impact on the drainage efficiency of the three-dimensional flow channel compared to the vibration amplitude. This study is of great significance for understanding the dynamics of droplets in PEMFC gas channels under vibration conditions as well as for optimizing the design and operating conditions of these channels.
Numerical study on the shock-induced ejecta formation from a grooved aluminum surface: The effect of groove size
Authors: Liang Yuan , Wu Lei , Shao Jian-Li , Xiao Yi-Hua
Published: June 2024

The structure of surface defects is one of the primary focuses in exploring the mechanism behind microjetting phenomena. However, the influence of defect size on microjets remains understudied. This work investigated the correlation between shock-induced microjets and surface defect scales under continuous approximation with the smoothed particle hydrodynamics method. The physical properties of microjets from generation to fragmentation were analyzed in detail. A relationship between the mass of different parts of the microjet and the defect size was established. The results indicate that the length of microjets and the jetting head velocity increase with the increase in the defect sizes. The jetting head velocity increases significantly when the defect depth is less than 4 μm, and the increase slows down when the defect depth is greater than 4 μm. This is attributed to the pressure and energy variations in the defect surface layer. A transition in the mass distribution of the microjet occurs when the defect depth reaches 7 μm. The jetting factor exhibits a trend of decreasing first and then increasing with the enlargement of defect size. The time of microjet fragmentation shows a proportional relationship with the defect size. By statistically analyzing the distribution of microjet fragmentation aggregates, it is found that the dispersal degree of microjet fragmentation aggregate sizes increases with defect size. This research reveals the correlation between the microjet and defect size.
Effects of inlet boundary conditions on nonlinear characteristics in numerical risers
Authors: Liu Guiliang , Yang Mo , Ying Xuchen
Published: June 2024

Fluidized beds are favored for their high efficiency in material and heat exchange. However, a limited understanding of two-phase flow dynamics leads to the construction of larger equipment and makes precise control of fluidized beds challenging. Since it is challenging to eliminate the impact of signal noise in experiments, which arises from the inconsistency of particles and measurement methods, a square fluidized bed model has been established for numerical analysis of the chaotic characteristics of two-phase flow. The bubble distribution in the fluidized bed was observed more clearly, the bubble behavior was combined with the chaotic parameters, and the two flow states and the chaotic state were analyzed comprehensively. The results show that the bubbles present a regular arrangement parallel to the diagonal in the early stage of bubbling. At the same time, smooth reconstructed attractors are observed. The increase in fluidization wind speed will make the attractors rough until collapse. The bubbling bed experiences bifurcation into chaos as the fluidization wind speed increases, and we can see this process through the pressure signal. The system state cannot be distinguished by correlation dimension or K-entropy alone. Comprehensive consideration of a variety of chaotic features can be used as a method to identify two-phase flow chaotic states. The method used in this paper combines bubble behavior, pressure signal, power spectrum analysis, phase space reconstruction, correlation dimension, and Kolmogorov entropy to distinguish the state of the fluidized bed more accurately.
Data-driven prediction of growth rate for a shocked heavy gas layer
Authors: Xie Jin , Zhou Zhangbo , Si Ting , Luo Xisheng
Published: June 2024

Numerical investigation on the evolution of a heavy gas layer is performed over a wide range of parameters. Neural networks and curve fitting techniques are employed to predict the growth rate of downstream interface based on 2688 simulated cases. Significant amounts of observable data are generated by considering four primary variables: shock wave intensity, density difference between the inside and outside of the gas layer, gas layer thickness, and initial interface shape. The neural network model maps the growth rate directly to the initial parameters, while the curve fitting approach provides an explicit formula. The neural network model has high accuracy and a certain extrapolation capability. The explicit formula provides a more intuitive understanding compared to the neural network model and has a stronger extrapolation. Furthermore, to thoroughly examine the evolution of the gas layer, the numerical investigation is conducted on the shocked single interface. It is discovered that there is a range of parameters in which the growth rate of gas layer is lower than that of the single interface. Meanwhile, a modified model that includes an attenuation factor is proposed to replace the impulsive model of the single interface. In summary, these methods can significantly reduce simulation time by quickly identifying desirable cases.
Meta-hydrodynamics for freely manipulating fluid flows
Authors: Wu Chen-Long , Wang Bin , Yao Neng-Zhi , Wang Hao , Wang Xuesheng
Published: June 2024

Flow control technologies play a crucial role in modern engineering and scientific research. Hydrodynamic metamaterials, as an emerging branch in the field of flow control, have attracted extensive research due to their remarkable potential in flow control, thus leading to the development of hydrodynamic metadevices. Here, we propose a meta-hydrodynamics theory for the active manipulation of fluid flows, which establishes an equivalence relation between volumetric forces and spaces and, consequently, allows for the design of active hydrodynamic metadevices. This equivalence relation can be utilized to accurately tailor the flow fields as long as the manipulation effects of the hydrodynamic metadevices on the flow fields are predetermined. By constructing a mapping relation of coordinate transformation from virtual space to physical space, we can determine the required volumetric force distributions to realize these hydrodynamic metadevices. We exemplify this theory with three different applications: hydrodynamic cloaks, concentrators, and rotators, for which we calculate the corresponding volumetric force distributions. Subsequent numerical simulations reveal the excellent manipulation performances of these hydrodynamic metadevices in both uniform and non-uniform flow fields. Finally, our research is expected to pioneer new perspectives in the development of hydrodynamic metadevices and methodologies for flow control under nonlinear flows with high Reynolds numbers.
Spatiotemporal typhoon impacts on wind speed field of offshore wind farms in the worst scenario of Chinese waters
Authors: Wang Hao , Lv Zhitong , Ren Lei , Ke Shitang , Wang Long , Wang Tongguang
Published: June 2024

The comprehensive examination of typhoon impacts on offshore wind power in Chinese waters, which are prone to severe typhoons, remains largely unexplored. This paper takes a step toward assessing extreme design wind conditions for offshore wind turbines in Chinese waters and investigates typhoon-induced wind conditions considering their spatiotemporal effects. For this purpose, a spatiotemporal analysis framework for typhoons was proposed that includes a data-driven typhoon wind speed field model and estimation method of the extreme wind speed. The wind speed field model introduces a measured correction coefficient to enhance the generalization across various observed typhoons, thereby accurately capturing spatiotemporal typhoon effects. The analysis framework was applied to dozens of typical worst-case scenarios of typhoons passing through offshore wind farms in Chinese waters. These scenarios were selected based on typhoon observation data from the past 30 years. The quantitative analysis assesses and discusses the spatiotemporal impacts of typhoons on the mean wind speed, fluctuating wind speed, extreme wind speed, peak factor, and gust factor. The results indicate significant spatiotemporal impacts of typhoons on the inflow wind speed field. The maximum gust wind speed difference could exceed tenfold at various times or for different turbines. This study offers an interpretation of why wind turbines within the same wind farm may experience varying degrees of damage during identical typhoon attacks. By examining the spatiotemporal variation characteristics of typhoons and the corresponding induced wind speed fields, this paper highlights the significance of these factors for typhoon-resistant design in offshore wind farms, thus aiding in ensuring the structural safety of offshore wind turbines.
Self-powered filterless narrowband AgNWs@ZnO:Ga/AlN/InGaN heterojunction photodetector for ultraviolet light intensimeter application
Authors: Yu Mengxin , He Siyuan , Liu Jinguo , Li Wenjie , Chen Mengdan , Cheng Dongping , Zhai Yalin , Shi Daning , Kan Caixia , Jiang Mingming
Published: June 2024

Self-powered high-performance photodetectors (PDs) featuring specific wavelengths are currently in high demand across various optoelectronic fields. Herein, we present a filter-free and self-biased narrowband PD, which contained a one-dimensional Ga-doped ZnO micro-crystal with surface-coated Ag nanowires, an InGaN film, and an AlN layer. The PD exhibits superior performance, containing a responsivity of 268.0 mA/W and a detectivity of 8.05 × 1011 Jones at 360 nm. Particularly for its narrowband photodetection (≤30 nm) and rapid response speed (100/700 μs), the PD enabled the development of a highly sensitive ultraviolet light intensimeter for monitoring weak signals (4–1500 μW/cm2) in combination with specially designed back-end circuits. Given its compact size and low relative error (≤1.5%), the rational design strategy can also be extended to other light detection systems, opening up a constructive way for the development of low-cost, high-sensitivity narrowband light detection.
Synapse-type-specific competitive Hebbian learning forms functional recurrent networks
Authors: Eckmann Samuel , Young Edward James , Gjorgjieva Julijana
Published: June 2024

Cortical networks exhibit complex stimulus–response patterns that are based on specific recurrent interactions between neurons. For example, the balance between excitatory and inhibitory currents has been identified as a central component of cortical computations. However, it remains unclear how the required synaptic connectivity can emerge in developing circuits where synapses between excitatory and inhibitory neurons are simultaneously plastic. Using theory and modeling, we propose that a wide range of cortical response properties can arise from a single plasticity paradigm that acts simultaneously at all excitatory and inhibitory connections—Hebbian learning that is stabilized by the synapse-type-specific competition for a limited supply of synaptic resources. In plastic recurrent circuits, this competition enables the formation and decorrelation of inhibition-balanced receptive fields. Networks develop an assembly structure with stronger synaptic connections between similarly tuned excitatory and inhibitory neurons and exhibit response normalization and orientation-specific center-surround suppression, reflecting the stimulus statistics during training. These results demonstrate how neurons can self-organize into functional networks and suggest an essential role for synapse-type-specific competitive learning in the development of cortical circuits.
Quantifying chemical short-range order in metallic alloys
Authors: Sheriff Killian , Cao Yifan , Smidt Tess , Freitas Rodrigo
Published: June 2024

Metallic alloys often form phases—known as solid solutions—in which chemical elements are spread out on the same crystal lattice in an almost random manner. The tendency of certain chemical motifs to be more common than others is known as chemical short-range order (SRO), and it has received substantial consideration in alloys with multiple chemical elements present in large concentrations due to their extreme configurational complexity (e.g., high-entropy alloys). SRO renders solid solutions “slightly less random than completely random,” which is a physically intuitive picture, but not easily quantifiable due to the sheer number of possible chemical motifs and their subtle spatial distribution on the lattice. Here, we present a multiscale method to predict and quantify the SRO state of an alloy with atomic resolution, incorporating machine learning techniques to bridge the gap between electronic-structure calculations and the characteristic length scale of SRO. The result is an approach capable of predicting SRO length scale in agreement with experimental measurements while comprehensively correlating SRO with fundamental quantities such as local lattice distortions. This work advances the quantitative understanding of solid-solution phases, paving the way for the rigorous incorporation of SRO length scales into predictive mechanical and thermodynamic models.
Mother left, Father right
Authors: Nyst Victoria , Schüller Anique
Published: June 2024

Studies of diachronic change in sign languages are only available for a small number of sign languages, in part
due to the scarcity of historical resources for sign languages. This article presents the first study of diachronic change in
Nederlandse Gebarentaal ‘Dutch Sign Language’ (NGT) and Vlaamse Gebarentaal ‘Flemish Sign
Language’ (VGT). It looks at the impact of an artificial sign system on the lexicons of the Gestel variant of NGT and the Limburg
variant of VGT. The recovery of two 19th century manuscripts describing 3,000 signs and 7,000 signs of this system respectively
enables us to compare this artificial system with published data for NGT and VGT from the 1950s and the present.

We focus on the resilience of an artificial distinction that is not considered distinctive in other natural sign
languages, i.e., an absolute left/right distinction for gender marking in kinship terms. The results show that the NGT and VGT
variants have partially changed or replaced all the artificial signs, except UNCLE/AUNT, NEPHEW/NIECE in NGT and PARENTS in VGT.
The partial changes shed light on the mechanisms through which artificial elements are nativized to fit the phonological system of
these sign languages. The changes observed in the left/right paradigm have implications for our understanding of the distribution
of laterality in sign language phonology in general.

Finally, the impact of the highly restricted access to language models that were part of the strict oralist
approaches in these school, and the consequent impoverished language input on diachronic change and lexical innovation are
discussed.
Organizational small storymaking
Authors: Bager Ann Starbæk , McClellan John G.
Published: June 2024

In this contribution, we place narrative theory in conversation with narrative practice to offer a small
storymaking approach for engendering organizational change. Drawing on insights from counter-narrative studies, small story
analysis, and communicative approaches to organizational change, we offer an applied narratology that conceptualizes
organizational change as occurring in small storymaking practices. Embracing discourse and communication as constitutive of
organizations, we invite narrative scholars to move beyond traditional distanced researcher positions to participate more actively
in the co-creation of small stories and thus enable more participatory, collaborative organizational change practices. Rather than
merely interpreting organizational stories, as in many traditional narrative studies, our applied narratology encourages
researchers to invite organizational participants to co-create stories of their potential futures. Through this tension-filled
practice of organizational small storymaking, narrative researchers and leaders can generate the ‘small story openings’ necessary
to inspire innovative change.