bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical Treatment of Upper Cervical Spine Trauma: Experience in a Regional Neurosurgery Unit in a Country with Limited Health Care Resources—About 22 Consecutives Cases
Authors: Faye Mohameth , Barry Louncény Fatoumata , Ilunga Roger Mulumba , Nacoulma Vital , Sy El Hadji Cheikh Ndiaye , Diop Abdoulaye , Donyo Téteh Yav-Edem Aristide , Atakla Hugues Ghislain , Cisse Yakhya , Wague Daouda , Koumare Izoudine Blaise , Gaye Magatte
Published: September 2023

Objectives Representing approximately 22% of cervical spine injuries, upper cervical spine injuries are becoming more frequent with the increase in road traffic accidents. The purpose of our study is to evaluate the results of our surgical series and to compare them with the literature.

Materials and Methods In this monocentric retrospective study of over three years (June 2019–May 2022), all the patients with traumatic injuries of the upper cervical spine with a surgical treatment and a minimum of 12 months follow-up were included.

Results The average age was 32.7 years, with a predominance of young patients. The predominant cause of injury was road traffic accident (86.3%). The clinical symptoms were cervical pain, associated with a motor deficit in two cases. Jefferson fracture associated with odontoid fracture was the most frequent injury (36.3%), followed by Hangman fracture (22.7%). Ten patients were treated with the Harms technique, four with occipitocervical C0-C2-C3 fixation, two with anterior screw insertion of the odontoid, and six with anterior C2-C3 arthrodesis. The average duration of follow-up was 12.2 months. The outcome was favorable in 21 cases and average in 1 case. Surgical morbidity and mortality were inexistent.

Conclusion This short series shows the effectiveness of surgical treatment in the managing traumatic injuries of the upper cervical spine and in the regression of the pain with a low risk of surgical morbidity and mortality.
Endoscopic Third Ventriculostomy versus Ventriculoperitoneal Shunt in Patients with Obstructive Hydrocephalus: An Updated Systematic Review and Meta-Analysis
Authors: Pasqualotto Eric , Schmidt Pedro Henrique Siedschlag , Ferreira Rafael Oliva Morgado , Chavez Matheus Pedrotti , da Silva Fernanda Feuerharmel Soares
Published: September 2023

Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) are surgical methods for treating obstructive hydrocephalus. However, there is still disagreement regarding the most effective technique, in terms of both operative success and postoperative complications. Therefore, we performed a systematic review and meta-analysis to compare the efficacy and safety of these two methods in patients with obstructive hydrocephalus. We performed a systematic search of the PubMed, Scopus, and Cochrane Library databases. Randomized clinical trials (RCTs) comparing ETV and VPS in pediatric or adult patients with obstructive hydrocephalus were included. The outcomes included were operative success, postoperative cerebrospinal fluid leak, postoperative infection, postoperative or intraoperative bleeding, blockage rate, and mortality. The risk ratio (RR) was calculated with a 95% confidence interval (CI). Heterogeneity was evaluated with I
2 statistics. We used a fixed-effects model for outcomes with I
2 < 25% and DerSimonian and Laird random-effects model for other conditions. The Cochrane collaboration tool for assessing the risk of bias in randomized trials was used for risk-of-bias assessment. R, version 4.2.1, was used for statistical analyses. Of the 2,353 identified studies, 5 RCTs were included, involving 310 patients with obstructive hydrocephalus, of which 163 underwent ETV. There was a significant difference in favor of ETV for postoperative infection (risk ratio [RR]: 0.11; 95% confidence interval [CI]: 0.04–0.33; p < 0.0001; I
2 = 0%) and blockage rate (RR: 0.15; 95% CI: 0.03–0.75; p = 0.02; I
2 = 53%). Meanwhile, there was no significant difference between groups for the postoperative or intraoperative bleeding (RR: 0.44; 95% CI: 0.17–1.15; p = 0.09; I
2 = 0%), postoperative cerebrospinal fluid leak (RR: 0.65; 95% CI: 0.22–1.92; p = 0.44; I
2 = 18%), operative success (RR: 1.18; 95% CI: 0.77–1.82; p = 0.44; I
2 = 84%), and mortality (RR: 0.19; 95% CI: 0.03–1.09; p = 0.06; I
2 = 0%). Three RCTs had some concerns about the risk of bias and one RCT had a high risk of bias due to the process of randomization and selection of reported results. Thus, this meta-analysis of RCTs evaluating ETV compared with VPS demonstrated that although there is no superiority of ETV in terms of operative success, the incidence of complications was significantly higher in patients who underwent VPS. Our results suggest that the use of ETV provides greater benefits for the treatment of obstructive hydrocephalus. However, more RCTs are needed to corroborate the superiority of ETV.
Human Orthopaedic Articles Convey Information Differently than Veterinary Orthopaedic Articles: A Prospective, Cross-Sectional Analysis
Authors: Evans Richard , Pozzi Antonio
Published: September 2023

The objective of this analysis was to compare the length and number of active voice sentences in human orthopaedic articles to veterinary orthopaedic articles. The goal is to provide authors and reviewers with objective, evidence-based guidelines to critically evaluate those two aspects of style of veterinary manuscripts during the writing phase of research and the review process. We used word counts and the percent of active voice sentences of the introduction sections and discussion sections in 15 randomly chosen veterinary orthopaedic clinical trial articles and 15 randomly chosen human orthopaedic clinical trial articles. Veterinary introduction sections were on average 193 words longer than human introduction sections (p = 0.001). Veterinary discussion sections were on average 370 words longer than human discussion sections. Veterinary introduction sections had on average 14.4 percent fewer active voice sentences than human introduction sections (p = 0.003). Veterinary discussion sections had on average 8.3 percent fewer active voice sentences than human discussion sections. Our conclusion is that human articles are written in a different style from veterinary clinical trial articles, which could be written with fewer words and more active sentences.
Multiple Symptomatic Spinal Intradural Arachnoid Cysts: A Case Report
Authors: Sharma Vikrant , Bhaskar Suryanarayanan , Tiwari Sarbesh
Published: September 2023

A spinal arachnoid cyst is a rare entity representing only 1 to 3% of spinal canal lesions. Very few of them are reported to be symptomatic. Moreover, occurrence in multiples is even rarer. Extradural type is more common than intradural. In the spine, it is rare in the sacral region. Other common pathologies, such as a dermoid or epidermoid cyst, are often considered at presentation. Even magnetic resonance imaging can miss the diagnosis sometimes. We report a case with symptoms of paraparesis and incontinence at presentation, initially misdiagnosed as a dermoid cyst, later found to be multiple intradural arachnoid cysts located in the sacral region. Spinal arachnoid cysts may cause debilitating symptoms. The disease is completely curable if the detection and classification are early as in our case.
Ventriculoperitoneal Shunt Surgery in Brunei Darussalam: A Population-Based Perspective
Authors: Boban Merlin , Mathew John , Thien Ady
Published: September 2023

Objective Ventriculoperitoneal shunt surgery is commonly performed to treat hydrocephalus. We aimed to characterize the demographics, complications, and outcomes of patients who underwent ventriculoperitoneal shunt surgery in Brunei Darussalam.

Materials and Methods We conducted a retrospective study on patients who underwent ventriculoperitoneal shunt surgery at the Neurosurgery Department of the Raja Isteri Pengiran Anak Saleha Hospital and Brunei Neuroscience Stroke and Rehabilitation Centre between January 2015 and June 2020.

Statistical Analysis All statistical analyses were performed using the Statistical Package for the Social Sciences version 20 (IBM Corporation, Armonk, New York, United States). The χ2 test, Student's t-test, and Mann–Whitney U test were performed for nominal, normally, and non-normally distributed variables, respectively. Multivariate logistic regression was used to assess the predictors of complications and shunt failure.

Results Fifty-three patients with a median age of 33 (interquartile range, 4–49) years were included. A total of 53 shunt operations were performed: 18 in the pediatric population and 35 in adults. The overall complication rate was 22.6%. Infection was the most common (9.4%) complication, with coagulase-negative staphylococci being the common organism causing the infection. The shunt failure rate (defined as removal or revision) was 20.8%. Univariate and multivariate analyses did not identify factors associated with complications or shunt failure.

Conclusion Ventriculoperitoneal shunt surgery, a common and technically non-demanding neurosurgical procedure, is associated with significant complications. We highlighted that shunt infection remains a concern and advocate practices to negate this risk.
Identifying trends and patterns in offending and victimization on Snapchat: a rapid review
Authors: Huie Kelly , Butler Michelle , Percy Andrew
Published: September 2023

Few studies have examined crime on Snapchat despite its popularity and growing accounts of victimization occurring on the application. This study addresses this gap in knowledge by conducting a rapid review of crime on Snapchat across 18 databases. The findings indicate this area is under-researched, with only 35 articles eligible for inclusion and five focusing solely on crime on Snapchat. Nevertheless, eleven types of crimes were identified as occurring on Snapchat, including: blackmail; the sharing of private, sexual material without consent; grooming/solicitation of minors; stalking; posting threatening, intimidating or harassing material; hate crime; sharing offensive, menacing or obscene content; obtaining illicit goods; identity theft; fraud; and hacking. The findings additionally revealed some patterns in offending and victimization that are also discussed.
The relation between football clubs and economic growth: the case of developed countries
Authors: Aygün Murat , Savaş Yunus , Alma Savaş Dilek
Published: September 2023

It is believed that societies use sports as a tool for their social and cultural development. In particular, developed countries have embraced sports as part of their lives and have ranked it as a source of economic growth. The increase in sports consumption and industries can contribute to economic growth, and economic growth can have a positive impact on sports industries vice versa. The wavelet methodology is a way to discover the relationship between sports and economic growth by examining frequency and time domain aspects and identifying shorter to longer-term relationships continuously. The industrial production of different countries has experienced short and medium-term cycles around the year 2020. In contrast, the values of football clubs in these countries have shown minimal fluctuations, despite the emergence of some areas with slight significance. The cross wavelet analysis asserted the significance relation revealed after the covid 19 restrictions, both in shorter and longer periods. The wavelet coherence analysis showed that co-movement was observed in short-term cycles in countries across the periods while long-term co-movements are observed only in only in small areas or generally out of cone of influence.
Ethics and discrimination in artificial intelligence-enabled recruitment practices
Authors: Chen Zhisheng
Published: September 2023

This study aims to address the research gap on algorithmic discrimination caused by AI-enabled recruitment and explore technical and managerial solutions. The primary research approach used is a literature review. The findings suggest that AI-enabled recruitment has the potential to enhance recruitment quality, increase efficiency, and reduce transactional work. However, algorithmic bias results in discriminatory hiring practices based on gender, race, color, and personality traits. The study indicates that algorithmic bias stems from limited raw data sets and biased algorithm designers. To mitigate this issue, it is recommended to implement technical measures, such as unbiased dataset frameworks and improved algorithmic transparency, as well as management measures like internal corporate ethical governance and external oversight. Employing Grounded Theory, the study conducted survey analysis to collect firsthand data on respondents’ experiences and perceptions of AI-driven recruitment applications and discrimination.
Exploring the dynamics of corruption perceptions in sustained anti-corruption campaigns: a survey experiment in China
Authors: Pan Yating , Shu Zhan , Ye Zhipeng
Published: September 2023

Evidence increasingly shows that anti-corruption investigations generate negative perceptions in the short run and lead to perceptions of reduced corruption in the long run. However, there is a lack of research on the effects of anti-corruption investigations on corruption perceptions within sustained anti-corruption campaigns. In certain nations, anti-corruption campaigns can be relentless. In such sustained campaigns, can fluctuations in the annual number of investigations affect corruption perceptions? This study aims to address the gap by conducting a survey experiment in China. The findings indicate that corruption perceptions are formed in an online evaluation fashion rather than a memory-based one. Individuals spontaneously form and revise their perceptions by integrating new information into their existing evaluations. Corruption perceptions are positively correlated with both the past trend in the annual number of investigations and recent investigations. Unexpected recent investigations can reverse people’s corruption perceptions that are based on past trends. These findings are applicable to other nations in which anti-corruption campaigns are sustained and anti-corruption information is publicly accessible.
Chimeras in globally coupled oscillators: A review
Authors: Mishra Arindam , Saha Suman , Dana Syamal K.
Published: September 2023

The surprising phenomenon of chimera in an ensemble of identical oscillators is no more strange behavior of network dynamics and reality. By this time, this symmetry breaking self-organized collective dynamics has been established in many networks, a ring of non-locally coupled oscillators, globally coupled networks, a three-dimensional network, and multi-layer networks. A variety of coupling and dynamical models in addition to the phase oscillators has been used for a successful observation of chimera patterns. Experimental verification has also been done using metronomes, pendula, chemical, and opto-electronic systems. The phenomenon has also been shown to appear in small networks, and hence, it is not size-dependent. We present here a brief review of the origin of chimera patterns restricting our discussions to networks of globally coupled identical oscillators only. The history of chimeras in globally coupled oscillators is older than what has been reported in nonlocally coupled phase oscillators much later. We elaborate the story of the origin of chimeras in globally coupled oscillators in a chronological order, within our limitations, and with brief descriptions of the significant contributions, including our personal experiences. We first introduce chimeras in non-locally coupled and other network configurations, in general, and then discuss about globally coupled networks in more detail.
Experimental realization of a quantum classification: Bell state measurement via machine learning
Authors: Wu Qing-Yuan , Meng Zhe , Chen Xiao-Xiao , Li Jian , Yang Jia-Zhi , Zhang An-Ning
Published: September 2023

The Bell state is a crucial resource for the realization of quantum information tasks, and when combined with orbital angular momentum (OAM), it enables a high-dimensional Hilbert space, which is essential for high-capacity quantum communication. In this study, we demonstrate the recognition of OAM Bell states using interference patterns generated by a classical light source and a single-photon source from a Sagnac interferometer-based OAM Bell state evolution device. The interference patterns exhibit a one-to-one correspondence with the input Bell states, providing conclusive evidence for the full recognition of OAM Bell states. Furthermore, we introduce machine learning to the field of Bell state recognition by proposing a neural network model capable of accurately recognizing higher order single-photon OAM Bell states, even in the undersampling case. In particular, the model’s training set includes interference patterns of OAM Bell states generated by classical light sources, yet it is able to recognize single-photon OAM Bell states with high accuracy, without relying on quantum resources during training. Our innovative application of neural networks to the recognition of single-photon OAM Bell states not only circumvents the resource consumption and experimental difficulties associated with quantum light sources but also facilitates the study of OAM-based quantum information.
Excitation of radially propagating electrostatic shear Alfvén wave during the formation of ambipolar radial electric field in a stochastic magnetic field
Authors: You Jinxiang , Wang Shaojie
Published: September 2023

A radially propagating electrostatic shear Alfvén wave (ωH mode) is found during the formation of ambipolar radial electric field in a magnetic stochastic layer through gyrokinetic simulation. It is found that the times scale of the ambipolar radial electric field formation is the damping time of the ωH mode. The frequency and damping rate of the ωH mode are theoretical derived, which are in good agreement with the simulation results.
Direct imaging of shock wave splitting in diamond at Mbar pressure
Authors: Makarov Sergey , Dyachkov Sergey , Pikuz Tatiana , Katagiri Kento , Nakamura Hirotaka , Zhakhovsky Vasily , Inogamov Nail , Khokhlov Victor , Martynenko Artem , Albertazzi Bruno , Rigon Gabriel , Mabey Paul , Hartley Nicholas J. , Inubushi Yuichi , Miyanishi Kohei , Sueda Keiichi , Togashi Tadashi , Yabashi Makina , Yabuuchi Toshinori , Okuchi Takuo , Kodama Ryosuke , Pikuz Sergey , Koenig Michel , Ozaki Norimasa
Published: September 2023

Understanding the behavior of matter at extreme pressures of the order of a megabar (Mbar) is essential to gain insight into various physical phenomena at macroscales—the formation of planets, young stars, and the cores of super-Earths, and at microscales—damage to ceramic materials and high-pressure plastic transformation and phase transitions in solids. Under dynamic compression of solids up to Mbar pressures, even a solid with high strength exhibits plastic properties, causing the induced shock wave to split in two: an elastic precursor and a plastic shock wave. This phenomenon is described by theoretical models based on indirect measurements of material response. The advent of x-ray free-electron lasers (XFELs) has made it possible to use their ultrashort pulses for direct observations of the propagation of shock waves in solid materials by the method of phase-contrast radiography. However, there is still a lack of comprehensive data for verification of theoretical models of different solids. Here, we present the results of an experiment in which the evolution of the coupled elastic–plastic wave structure in diamond was directly observed and studied with submicrometer spatial resolution, using the unique capabilities of the x-ray free-electron laser (XFEL). The direct measurements allowed, for the first time, the fitting and validation of the 2D failure model for diamond in the range of several Mbar. Our experimental approach opens new possibilities for the direct verification and construction of equations of state of matter in the ultra-high-stress range, which are relevant to solving a variety of problems in high-energy-density physics.
Side-jump scattering enhanced spin Hall effect in SrTiO3-implanted Pt
Authors: Lin Zijin , Xu Xinkai , Zhang Lei , Wei Junwen , Zhong Zhiyong , Tang Xiaoli , Jin Lichuan
Published: September 2023

A spin Hall effect (SHE) enables the electrical generation and detection of spin currents for promising applications in spintronics, but heavy metals with low spin Hall angle θSH limit the development of SHE devices. In this work, we have introduced dielectric oxide material SrTiO3 into Pt by magnetron sputtering and measured the θSH on the NiCo/Pt1–x(STO)x heterostructure through spin-torque ferromagnetic resonance. Our results demonstrate that the maximum spin Hall angle in Pt0.98(STO)0.02 is 0.121 ± 0.003, which is approximately twice that of pure Pt (0.064 ± 0.003). Moreover, theoretical analysis has revealed that the spin Hall angle arises from a complementary interplay between intrinsic and extrinsic mechanisms, namely, the strong spin–orbit coupling in Pt for the intrinsic mechanism and side-jump scattering caused by scalar potential and lattice expansion at dielectric impurities for the extrinsic mechanism. This interplay significantly contributes to enhancing the spin Hall angle. This work demonstrates an effective strategy for fabricating high-performance spin Hall materials with low resistivity, large spin Hall angle, and excellent compatibility with semiconductor processes in low-power spin-torque devices.
Resistivity size effect in epitaxial VNi2 layers
Authors: Zhang Minghua , Gall Daniel
Published: September 2023

Epitaxial VNi2 layers are deposited onto MgO(001) and their resistivity ρ measured as a function of layer thickness d = 10.5–138 nm to quantify the resistivity size effect. The layers exhibit resistivity minima at both stoichiometric V:Ni = 1:2 composition and 700 °C growth temperature, which is attributed to electron scattering at V–Ni antisite defects and is described using the ordering parameter within the framework by Rossiter. A cube-on-cube epitaxy of the fcc parent structure on MgO(001) leads to two possible layer orientations for orthorhombic VNi2(010) and VNi2(103), resulting in considerable atomic disorder at domain boundaries, consistent with relatively small x-ray coherence lengths of 8 and 14 nm in-plane and along the growth direction of a 33.5 nm thick layer. In situ ρ vs d measurements yield a bulk resistivity of ρo = 46 ± 2 μ Ω cm and a benchmark quantity of ρoλ = (138 ± 5) × 10−16 Ω m2, where λ is the bulk electron mean free path. Air exposure causes a minor resistivity increase due to 2 ± 1 nm thick surface oxide that perturbs the surface potential. Resistivities at 77 K are Δρ = 16 ± 3 μ Ω cm below those at room temperature. This Δρ is thickness independent and is close to the previously predicted 13.9 μ Ω cm bulk resistivity for VNi2 along [100]. However, the measured bulk resistivity is well above this prediction, which is attributed to electron scattering at domain boundaries/atomic disorder. Consequently, the theoretically predicted superior directional conduction cannot be experimentally confirmed in this study. The overall results indicate that VNi2 is only a promising compound for narrow interconnects if a synthesis scheme can be developed that results in a strong atomic order, a negligible domain boundary density, and a [100] crystalline orientation along the transport direction.
Atom probe tomography using an extreme ultraviolet trigger pulse
Authors: Caplins Benjamin W. , Chiaramonti Ann N. , Garcia Jacob M. , Sanford Norman A. , Miaja-Avila Luis
Published: September 2023

Atom probe tomography (APT) is a powerful materials characterization technique capable of measuring the isotopically resolved three-dimensional (3D) structure of nanoscale specimens with atomic resolution. Modern APT instrumentation most often uses an optical pulse to trigger field ion evaporation—most commonly, the second or third harmonic of a Nd laser is utilized (∼λ = 532 nm or λ = 355 nm). Herein, we describe an APT instrument that utilizes ultrafast extreme ultraviolet (EUV) optical pulses to trigger field ion emission. The EUV light is generated via a commercially available high harmonic generation system based on a noble-gas-filled capillary. The centroid of the EUV spectrum is tunable from around 25 eV (λ = 50 nm) to 45 eV (λ = 28 nm), dependent on the identity of the gas in the capillary (Xe, Kr, or Ar). EUV pulses are delivered to the APT analysis chamber via a vacuum beamline that was optimized to maximize photon flux at the APT specimen apex while minimizing complexity. We describe the design of the beamline in detail, including the various compromises involved. We characterize the spectrum of the EUV light and its evolution as it propagates through the various optical elements. The EUV focus spot size is measured at the APT specimen plane, and the effects of misalignment are simulated and discussed. The long-term stability of the EUV source has been demonstrated for more than a year. Finally, APT mass spectra are shown, demonstrating the instrument’s ability to successfully trigger field ion emission from semiconductors (Si, GaN) and insulating materials (Al2O3).
Analysis of different modeling approaches for simulation of glow discharge in helium at atmospheric pressure
Authors: Rafatov Ismail , Islamov Gubad , Eylenceoglu Ender , Yesil Cihan , Bogdanov Eugeny
Published: September 2023

One-dimensional numerical models of a direct current atmospheric pressure glow discharge in helium are developed and examined. The models use a fluid description of charged and neutral particles and a drift-diffusion approximation for particle fluxes. The effects of plasma-chemical models, the form of the electron energy distribution function (Maxwellian vs non-Maxwellian), the energy loss due to gas heating and the width of the gas gap on the discharge characteristics are analyzed. The performance of different modeling approaches is examined by superimposing computed current–voltage characteristic (CVC) curves with each other and with measured and computed CVCs available in the literature.
Physics-regulated dynamic mode decomposition for natural gas pipeline flow
Authors: Koo Bonchan , Chang Seungjoon , Kim Hyoung-Ho , Park Sung Goon
Published: September 2023

This study introduces a novel integration of dynamic mode decomposition (DMD) with physical regulations for natural gas pipeline flow. It aims to address the limitations of purely data-driven models and the importance of incorporating the physics of complex dynamic systems. By considering the mass conservation law, the proposed model ensures that the predictions generated via DMD with control adhere to the physical laws, resulting in a multi-objective optimization problem. To verify its performance, the proposed model was evaluated using real-world data of natural gas pipelines. The results demonstrate its superior accuracy and ability to avoid physically implausible predictions, particularly under data-limited conditions. Despite an increase in the overall computational cost by approximately 15%, the model achieved up to 50% error reduction with scarce training data, highlighting its robustness and effectiveness. This study represents a significant advancement in data-driven modeling techniques by fulfilling the critical need for accurate and reliable predictions that respect physical constraints, thus enhancing the interpretability and validity of the results.
Tokamak plasma equilibrium with relativistic runaway electrons
Authors: Bandaru V. , Hoelzl M.
Published: September 2023

We consider axisymmetric equilibrium of a tokamak plasma that includes current carried by relativistic runaway electrons (REs). Using a guiding center approach, a qualitative picture of the equilibrium of a pure RE beam is elucidated. In a hot thermal plasma, none of the classical drifts of charged particles contribute to the net field-perpendicular current density, which is purely due to magnetization current. In the case of a runaway beam, however, the curvature drift of REs provides the Lorentz force needed to maintain the centripetal acceleration associated with the relativistic toroidal motion. Two different equilibrium formulations are derived for the general case consisting of a mix of thermal and RE current. At higher RE energies, the shift between flux-surfaces and surfaces of constant generalized angular momentum of REs in such equilibria can exceed the radial extent of a typical magnetohydrodynamic mode such that its stability properties could be altered. Simplified one-dimensional governing equations are derived for the absolute and relative orbit shifts in the case of a circular tokamak, enabling quick estimates of parameter dependencies.
Analysis of molten metal fluid flow mechanisms in variable polarity plasma arc welding of aluminum alloys
Authors: Liu Jingbo , Jiang Fan , Chen Shujun , Xu Bin , Zhang Guokai
Published: September 2023

The stability and quality of welding in variable polarity plasma arc welding are determined by the directional fluid flow within the molten pool. In this study, the particle tracking method was employed to obtain flow traces and velocity of the molten metal on the walls of the keyhole using a high-speed camera system. Additionally, a confocal laser scanning microscope was utilized to capture the 3D morphology of the keyhole, while the flow channels were obtained through sectioning. By correlating the flow traces and velocity with the 3D keyhole morphology, the experimental results revealed the presence of saddle points on both the front and rear walls of the keyhole. The front saddle point represents the region where the flow velocity in the depth direction is minimum, causing the keyhole front side to converge upward and downward. The depth and volume of fluid flow to the keyhole sidewall are determined by this front saddle point. On the other hand, the rear saddle point is located at the center of the molten pool, marking the entry and exit sides of the keyhole rear wall where the melting metal eventually reaches. The location of the post-settlement point will affect the weld state. During the welding process, the double saddle points of the molten pool remain dynamically stable, and their position is influenced by shear force, gravity, arc pressure, keyhole morphology, and flow channels. These findings contribute to controlling the process characteristics necessary for stable welding of the keyhole in the molten pool.
Evolution of the microstructure of amorphous polyethylene under friction-induced plastic flows: A reactive molecular investigation
Authors: Zheng Ting , Gu Jingxuan , Zhang Yu , Zhang Huichen
Published: September 2023

The plastic flow of ultra-high molecular weight polyethylene (UHMWPE) at a frictional interface, which is critical to the wear behavior, was investigated by reactive molecular dynamics simulations. The UHMWPE substrate was found to experience various deformations during the friction process. First, some polyethylene (PE) chains could detach from the substrate because of their rapid movement. Second, the frequent motion of PE chains also resulted in the intermittent formation and breaking of cavities between intermolecular PE chains. These deformations were more obvious on a surface with a convex protrusion, where the plowing effect exacerbated the cavitation and elastic deformation of PE chains. Correspondingly, the plastic flow in turn reconstructed the convex protrusion by displacing the surface atoms on the Fe slab. The plastic flow of PE chains broke the C–C bonds, and the carbon moieties were then chemically bonded onto the metal surface. A rapid change of atomic charge, hence, happened when the bonds broke. Meanwhile, PE chains release short alkyl radicals gradually after bond breakage, indicating gradual wear of the substrate during friction. This work provides molecular insight into the evolution of interfacial microstructure under plastic flow on a UHMWPE substrate.
Two-dimensional terahertz beam manipulations based on liquid-crystal-assisted programmable metasurface
Authors: Fu Yuan , Fu Xiaojian , Yang Silei , Peng Shuang , Wang Peng , Liu Yujie , Yang Jun , Wu Jingbo , Cui Tie Jun
Published: September 2023

In this paper, an approach is proposed toward two-dimensional (2D) beam tailoring in the terahertz band based on programmable metasurface loaded with liquid crystals. Specifically, a 1-bit reflective metasurface element is designed with switchable phase responses, and subsequently, an individually controllable metasurface array in 2D fashion is achieved by pixelating the metallic reflection back plate. As typical examples, programmable metasurfaces operating around 94 and 220 GHz are developed, respectively, and both simulation and experimental results confirm the powerful abilities of the metasurfaces in 2D wide-angle beam manipulations. In addition, the proposed method has advantages of wide frequency range, low cost, and high reliability, implying significant application prospects in terahertz reconfigurable intelligent surfaces and holographic imaging.
The fast block to polyspermy breaks with convention
Authors: Short Ben
Published: September 2023

JGP study (Komondor et al. 2023. J. Gen. Physiol. https://doi.org/10.1085/jgp.202213258) reveals that conventional PLC activation pathways are not required for the fertilization-induced depolarization of Xenopus eggs that prevents the entry of additional sperm.
An automated parameter domain decomposition approach for gravitational wave surrogates using hp-greedy refinement
Authors: Cerino Franco , Andrés Diaz-Pace J , Tiglio Manuel
Published: September 2023

We introduce hp-greedy, a refinement approach for building gravitational wave (GW) surrogates as an extension of the standard reduced basis framework. Our proposal is data-driven, with a domain decomposition of the parameter space, local reduced basis, and a binary tree as the resulting structure, which are obtained in an automated way. When compared to the standard global reduced basis approach, the numerical simulations of our proposal show three salient features: (i) representations of lower dimension with no loss of accuracy, (ii) a significantly higher accuracy for a fixed maximum dimensionality of the basis, in some cases by orders of magnitude, and (iii) results that depend on the reduced basis seed choice used by the refinement algorithm. We first illustrate the key parts of our approach with a toy model and then present a more realistic use case of GWs emitted by the collision of two spinning, non-precessing black holes. We discuss performance aspects of hp-greedy, such as overfitting with respect to the depth of the tree structure, and other hyperparameter dependences. As two direct applications of the proposed hp-greedy refinement, we envision: (i) a further acceleration of statistical inference, which might be complementary to focused reduced-order quadratures, and (ii) the search of GWs through clustering and nearest neighbors.
Automated vehicle wheelbase measurement using computer vision and view geometry
Authors: Liu Yingkai , Han Dayong , Cao Ran , Guo Jingjing , Deng Lu
Published: September 2023

For different transportation agencies that monitor vehicle overloads, develop policies to mitigate the impact of vehicles on infrastructure, and provide the necessary data for road maintenance, they all rely on precise, detailed and real-time vehicle data. Currently, real-time collection of vehicle data (type, axle load, geometry, etc) is typically performed through weigh-in-motion (WIM) stations. In particular, the bridge WIM (BWIM) technology, which uses instrumented bridges as weighing platforms, has proven to be the most widely used inspection method. For most of the BWIM algorithms, the position of the vehicle’s axle (i.e. vehicle wheelbase) needs to be measured before calculating the axle load, and the identification of the axle load is very sensitive to the accuracy of the vehicle wheelbase. In addition, the vehicle’s wheelbase is also important data when counting stochastic traffic flow and classifying passing vehicles. When performing these statistics, the amount of data is often very large, and the statistics can take years or even decades to complete. Traditional manual inspection and recording approaches are clearly not up to the task. Therefore, to achieve automatic measurement of the on-road vehicles’ wheelbase, a framework based on computer vision and view geometry is developed. First, images of on-road vehicles are captured. From the images, the vehicle and wheel regions can be accurately detected based on the You Only Look Once version 5 (YOLOv5) architecture. Then, the residual unified network model is improved and an accurate semantic segmentation of the wheel within the bounding box is performed. Finally, a view geometry-based algorithm is developed for identifying vehicle wheelbase. The accuracy of the proposed method is verified by comparing the identified results with the true wheelbases of both two-axle vehicles and multi-axis vehicles. To further validate the effectiveness and robustness of the framework, the effects of important factors, such as camera position, vehicle angle, and camera resolution, are investigated through parametric studies. To illustrate its superiority, the developed vehicle wheelbase measurement algorithm is compared with two other advanced vehicle geometry parameter identification algorithms and the results show that the developed algorithm outperforms the other two methods in terms of the degree of automation and accuracy.
Fabrication of magnetic α-Fe2O3/Fe3O4 heterostructure nanorods via the urea hydrolysis-calcination process and their biocompatibility with LO2 and HepG2 cells
Authors: Zhu Ziye , Ouyang Hezhong , Ling Chen , Ma Mingyi , Wang Jie , Yu Xiang , Li Yongjin
Published: September 2023

β-FeOOH nanorods were prepared via the urea hydrolysis process with the average length of 289.1 nm and average diameter of 61.2 nm, while magnetic α-Fe2O3/Fe3O4 heterostructure nanorods were prepared via the urea calcination process with β-FeOOH nanorods as precursor, and the optimum conditions were the calcination temperature of 400 °C, the calcination time of 2 h, the β-FeOOH/urea mass ratio of 1:6. The average length, diameter, and the saturation magnetization of the heterostructure nanorods prepared under the optimum conditions were 328.8 nm, 63.4 nm and 42 emu·g−1, respectively. The Prussian blue test demonstrated that the heterostructure nanorods could be taken up by HepG2 cells, and cytotoxicity tests proved that the heterostructure nanorods had no significant effect on the viabilities of LO2 and HepG2 cells within 72 h in the range of 100–1600 μg·ml−1. Therefore, magnetic α-Fe2O3/Fe3O4 heterostructure nanorods had better biocompatibility with LO2 and HepG2 cells.
Bi-Layer nanoimprinting lithography for metal-assisted chemical etching with application on silicon mold replication
Authors: Chen Wei-Shen , Lee Yung-Chun
Published: September 2023

This paper reports a new type of nanoimprinting method called Bi-layer nanoimprinting lithography (BL-NIL), which can work along with metal-assisted chemical etching (MaCE) for fabricating nanostructures on silicon. In contrast to conventional nanoimprinting techniques, BL-NIL adds an interposing layer between the imprinting resist layer and silicon substrate. After the standard imprinting process, dry etching was used to etch away the residual imprinting layer and part of the interposing layer. Finally, the remaining interposing layer was wet-etched using its remover. This innovative approach can ensure cleanliness at the metal/silicon interface after metal lift-off processes, and therefore guarantees the success of MaCE. By combining BL-NIL and MaCE, expensive silicon molds with sub-micrometer/nanometer-scale feature sizes can be easily replicated and preserved. This is important for the application of nanoimprinting technologies in industrial manufacturing.
Oxygen atom and ozone kinetics in the afterglow of a pulse-modulated DC discharge in pure O2: an experimental and modelling study of surface mechanisms and ozone vibrational kinetics
Authors: Booth J-P , Guaitella O , Zhang S , Lopaev D , Zyryanov S , Rakhimova T , Voloshin D , Chukalovsky A , Volynets A , Mankelevich Yu
Published: September 2023

The chemical kinetics of oxygen atoms and ozone molecules were investigated in a fully-modulated DC discharge in pure oxygen gas in a borosilicate glass tube, using cavity ringdown spectroscopy (CRDS) of the optically forbidden O(3P2)→O(1D2) absorption at 630 nm. Measurements were made over a range of tube temperatures (10 °C and 50 °C) gas pressures (0.5–4 Torr) and discharge current (10–40 mA). The discharge current was square-wave modulated (on for 0.2 s and off for 1 s), allowing the build-up to steady-state and the decay in the afterglow to be studied. This paper focusses on the afterglow period. The O atom density decays non-exponentially in the afterglow, indicating a surface loss probability dependent on incident active particle fluxes. The oxygen atom absorption peak lies on a time-varying absorption continuum due (in the afterglow) to the Chappuis bands of ozone. The ozone density passes through a maximum a few 100 ms into the afterglow, then decays slowly. An existing time-resolved self-consistent 1D radial model of O2 positive column discharges was modified to interpret the new results. The ozone behaviour in the afterglow can only be modelled by the inclusion of: (1) surface production of O3 from the reaction of O2 molecules with adsorbed O atoms, (2) reactions of vibrationally-excited ozone with O atoms and with O2(a1Δg) molecules, and (3) surface loss of ozone with a probability of around 10−5.
The fastest generation of multipartite entanglement with natural interactions
Authors: Cieśliński Paweł , Kłobus Waldemar , Kurzyński Paweł , Paterek Tomasz , Laskowski Wiesław
Published: September 2023

Natural interactions among multiple quantum objects are fundamentally composed of two-body terms only. In contradistinction, single global unitaries that generate highly entangled states typically arise from Hamiltonians that couple multiple individual subsystems simultaneously. Here, we study the time to produce strongly nonclassical multipartite correlations with a single unitary generated by the natural interactions. We restrict the symmetry of two-body interactions to match the symmetry of the target states and focus on the fastest generation of multipartite entangled Greenberger–Horne–Zeilinger, W, Dicke and absolutely maximally entangled states for up to seven qubits. These results are obtained by constraining the energy in the system and accordingly can be seen as state-dependent quantum speed limits for symmetry-adjusted natural interactions. They give rise to a counter-intuitive effect where the creation of particular entangled states with an increasing number of particles does not require more time. The methods used rely on extensive numerical simulations and analytical estimations.
The research of declared primary frequency capacity and control strategy for electrical fused magnesium furnace load
Authors: Jia Yilin , Hao Rui , Guo Litao , Gao Lei , Sun Yongchao , Li Weidong
Published: September 2023

As a potential control resource of the load side, fused magnesium load can effectively make up for the loss of the primary frequency modulation capacity of the system, in which the conventional units are replaced by new energy sources. However, the capacity of fused magnesium load is closely related to the operating condition and changes dynamically. It is necessary to accurately characterize its capacity and determine the optimal declared capacity of participating in frequency modulation service. According to the technical regulations of primary frequency modulation service, the basic principle is presented, which the electric molten magnesium load participates in primary frequency modulation control in the case of lack of large power. Considering the risk of reward and punishment, the optimal reporting capacity optimization model is constructed. Taking the year as the time scale, a stochastic production simulation method involving primary frequency modulation was proposed. According to its operating characteristics, a real-time control strategy involving primary frequency modulation is designed. Simulation examples show that the proposed method can accurately simulate the production process of molten magnesium load, reasonably realize the operation control of molten magnesium load, and optimize the declared capacity considering the risk.
Low-carbon Economic Scheduling of Combined Cooling, Heating and Power Microgrid Considering Demand Response and Shared Energy Storage
Authors: Wu Na , Yan Jingrui , Fan Shuxian , Hu Songge
Published: September 2023

In order to further promote the new energy consumption of combined cooling, heating, and power (CCHP) microgrid, reduce carbon emissions, and optimize the total operating cost of the microgrid, a low-carbon optimal scheduling model of CCHP microgrid was proposed. It considered demand response (DR) and shared energy storage (SES). Firstly, the concept of SES and its operation mode are applied to the microgrid. Secondly, in order to take advantage of the flexible nature of multiple loads, an integrated demand response (IDR) model with a ladder subsidy mechanism was established. Then, the optimal scheduling model introduces a reward and punishment ladder carbon trading mechanism (RPL-CTM). Finally, taking energy purchase cost, load reduction subsidy cost, interaction cost with energy storage station, carbon trading cost, and wind abandoning penalty cost as optimization objectives, a multi-energy coupling, and multi-objective collaborative optimization scheduling model was established. Numerical analysis indicates that the model can efficiently lower the microgrid’s operating cost and encourage the use of clean energy and carbon emission reduction.
Lithium Titanate battery-based frequency modulation control strategy for doubly fed induction generator
Authors: Tian Yuting , Wei Wei , Sun Xiwei , Li Xiaozhu
Published: September 2023

This paper proposes a Lithium Titanate battery-based primary frequency regulation strategy for doubly fed induction generators to solve the problems of a decrease in power generation efficiency and an increase in turbine losses under a traditional over-speed load shedding control strategy. A stator voltage orientation-based dual closed-loop control strategy for the vector control system is designed for the PWM rotor converter. A grid voltage-oriented vector control is adopted for the grid converter to maintain the stability of DC bus voltage. To enable a single doubly fed induction generator to have primary frequency regulation capability, a dual Lithium Titanate energy storage device is installed on the DC bus to improve the power generation efficiency of the unit. Modeling and analysis on Matlab/Simulink to verify that the proposed control strategy not only ensures the economic benefits of the generator’s electricity but also enables the generator to have good frequency regulation capability.
Transmission line icing thickness prediction model based on ISSA-CNN-LSTM
Authors: Han Zilong , Lv Hongtu , Liang Zhengding , Yi Jinqiao
Published: September 2023

The prediction of transmission line ice cover thickness can effectively guide the scientific operation and maintenance of the power sector. An improved sparrow search algorithm, convolutional neural network and long short-term memory fusion ice cover prediction model is proposed in this paper. Environmental temperature, humidity, wind speed and other data are firstly normalised, CNN is used to both learn the data signature as well as input the results into LSTM, and then ISSA is used to optimise the parameters of LSTM such as the numeration of the neuron, the initial learning rate, and the regularisation coefficient, etc., and then the final output is the predicted value of the icing thickness of the transmission line cover. The simulation results show that the MSE and MAE of the ISSA-CNN-LSTM model are 0.23 and 0.37, respectively, which are much better than the prediction results of the SSA and CNN models.