bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical evaluation of a novel single-use therapeutic gastroscope: a pilot feasibility study
Authors: Römmele Christoph , Ayoub Mousa , Wanzl Julia , Tadic Vidan , Braun Georg , Weber Tobias , Scheppach Markus Wolfgang , Roser David , Matic Katharina , Nagl Sandra , Messmann Helmut , Ebigbo Alanna
Published: October 2024

Background The trend toward disposable products in gastrointestinal endoscopy, including single-use endoscopes, remains undeterred, even though crucial questions of sustainability and performance have not been sufficiently studied. The first single-use therapeutic gastroscope was recently approved in Europe, but clinical data to support its use are currently lacking. We aimed to evaluate the performance of this novel device in routine procedures requiring a large working channel.

Methods Between January and May 2024, consecutive patients with an indication for therapeutic gastroscopy were included prospectively. The primary outcome was intraprocedural technical success rate.

Results Eight gastrointestinal bleedings, two pancreatic necrosectomies, four foreign body removals, four stent placements, and two cryo-balloon ablations were performed. The technical success rate was 84% (16/19 patients). Crossover to a standard endoscope was required in three procedures. Clinical success was achieved in all cases with technical success. Overall user experience was 3.2 on a Likert scale of 1–5. No adverse events were reported.

Conclusions The single-use therapeutic gastroscope demonstrated feasibility in various therapeutic procedures; however, a 16% crossover rate and fair user assessment score suggest that further technical improvements to the device are necessary.
Single Institution Experience with Lumbar Drainage and Subarachnoid Hemorrhage
Authors: Coggins William S. , Banko Lauren E. , Chokhani Purav , Rushing Elise G. , Necarsulmer Julie , Sasaki-Adams Deanna
Published: October 2024

Introduction In our article, we evaluate the effect of lumbar drainage on delayed cerebral ischemia and requirements for permanent cerebrospinal fluid diversion in patients with aneurysmal subarachnoid hemorrhage.

Methods We performed a retrospective cohort study from 2014 to 2023 at the University of Arkansas for Medical Sciences (UAMS) examining factors associated with patients (n = 150) who had aneurysmal subarachnoid hemorrhage and a lumbar drain placed. The main outcomes examined were incidence of delayed cerebral ischemia, need for permanent cerebrospinal fluid diversion, and neurologic outcomes at discharge that were compared to currently published standards.

Results We failed to appreciate a reduced occurrence of delayed cerebral ischemia (37.3% with the current literature supporting rates of 20–30%); however, we did find a low rate of requiring permanent cerebrospinal fluid diversion (12% compared to 10–20% in the current literature) with overall good neurologic outcomes at discharge (∼69% of patients had a Glasgow Outcome Scale [GOS] of 4–5 at discharge). Patients with GOS ≥ 4 at discharge were noted to be more likely to have more days or lumbar drainage and less likely to be older than 65 years, have had an external ventricular drain placed, and have experienced delayed cerebral ischemia.

Conclusion Lumbar drainage is a potentially useful adjunct in the management of secondary neurologic injury in subarachnoid hemorrhage.
Radiomic Applications in Skull Base Pathology: A Systematic Review of Potential Clinical Uses
Authors: Tenhoeve Samuel A. , Lefler Sydnee , Brown Julian , Owens Monica-Rae , Rawson Clayton , Tabachnick Dora R. , Shaik Kamal , Karsy Michael
Published: October 2024

Objectives Radiomics involves the extraction and analysis of numerous quantitative features of medical imaging which can add more information from radiological images often beyond initial comprehension of a clinician. Unlike deep learning, radiomics allows some understanding of identified quantitative features for clinical prediction. We sought to explore the current state of radiomics applications in the skull base literature.

Methods A systematic review of studies evaluating radiomics in skull base was performed, including those with and without machine-learning approaches. Studies were summarized into thematic elements as well as specific pathologies.

Results A total of 102 studies with 26,280 radiographic images were included. The earliest radiomic study was published in 2017 with exponential growth in research since then. Most studies focused on tumor diagnosis (40.8%), followed by tumor prognosis (31.1%), automated segmentation (16.5%), other applications (7.8%), and lastly prediction of intraoperative features (3.9%). Pituitary adenomas (41.7%) and vestibular schwannomas (18.4%) represented the most commonly evaluated pathologies; however, radiomics could be applied to a heterogeneous collection of skull base pathologies. The average study included 258 ± 677 cases (range 4; 6,755).

Conclusion Radiomics offers many functions in treating skull base pathology and will likely be an essential component of future clinical care. Larger sample sizes, validation of predictive models, and clinical application are needed. Further investigation into the strengths and weaknesses of radiomic applications in skull base treatments is warranted.
Thromboembolic Complications in Takotsubo Cardiomyopathy
Authors: Habib Manhal , Aronson Doron
Published: October 2024

Apical ballooning syndrome, commonly known as Takotsubo syndrome, is a distinct cardiomyopathy often resembling acute myocardial infarction in presentation. Takotsubo syndrome patients exhibit varied patterns of left ventricular wall motion abnormalities, most frequently apical dyskinesis with basal hyperkinesis, that are characteristically transient. Although emotional or physical stressors precipitate Takotsubo syndrome in most cases, a significant proportion presents without identifiable triggers, with a pronounced female predominance. Despite recovery of left ventricular function, Takotsubo syndrome may lead to serious complications akin to acute coronary syndromes. The pathophysiology remains incompletely understood, with catecholamine surge implicated in the genesis of myocardial injury, although direct causation remains debated. Diagnosis involves integrating clinical history, imaging modalities like echocardiography, and cardiac MRI. Psychiatric disorders, particularly anxiety and depression, are frequently associated with Takotsubo syndrome, suggesting a role of chronic stress in disease susceptibility. Management includes supportive care, with anticoagulation considered in cases of apical thrombus, alongside close monitoring for complications and recovery of left ventricular function. This article reviews the current understanding, challenges in diagnosis, and management strategies for Takotsubo syndrome.
Existence of solution to Hadamard–Caputo fractional differential equation with time delay
Authors: Gao Shanshan , Ge Bin
Published: October 2024

This article focuses on the study of the existence of solution to Hadamard–Caputo fractional nonlinear differential equation with time delay. For time delay, two different cases of finite delay and infinite delay are considered. Based on the weighted function solution spaces, the existence and uniqueness of solution to the differential equations are verified by Leray–Schauder selection theorem and Banach fixed point theorem respectively. Finally, examples are given to illustrate the abstract results of this article.
Surface plasmons on silver gratings transform pyrolytic carbon into luminescent graphitized carbon dots
Authors: Walia Jaspreet , Rashid Sabaa , Amiri Naeini Maryam Sadat , Killaire Graham , Variola Fabio , Weck Arnaud , Berini Pierre
Published: October 2024

Plasmonic catalysis holds the promise of opening new reaction pathways that are inaccessible thermally or via direct UV–vis electronic transitions. Here, energetic carriers produced via the decay of surface plasmons excited by visible light at 532 nm (2.33 eV, green) on a Ag-grating-bearing pyrolytic carbon residue drive its transformation into light-emitting graphitized carbon dots. The pyrolytic carbon residue is detectable via high-magnification surface-enhanced Raman scattering but cannot be directly observed using optical, electron, atomic force, or helium ion microscopy. When a Ag-grating-bearing pyrolyzed residue is introduced into a high-purity O2-depleted gas environment (Ar, N2, and CO2) and excited with 532 nm light, bright yellow luminescence emerges and is readily observed. Light emission is not observed without the pyrolytic carbon, without the excitation of plasmons, or in air or an Ar/O2 gas mixture. This process, driven by visible light and a nanostructured Ag surface bearing pyrolytic carbon, will be of interest to researchers involved in plasmonic catalysis, catalytic processes involving carbon, and luminescent plasmonic surfaces.
Theoretical investigation of Rayleigh-type surface acoustic waves with high electromechanical coupling coefficient in c-axis-tilted ScAlN film/3C-SiC substrate structure
Authors: Tominaga Takumi
Published: October 2024

Surface acoustic wave (SAW) resonators are essential components of mobile communication technology. Advanced performance SAW resonators are needed to support beyond fifth-generation mobile communication technology, which aims to achieve unprecedentedly high data rates and low latency using wide frequency bands in the RF spectrum. This study theoretically investigates the propagation characteristics of a non-leaky Rayleigh-type SAW (RSAW) propagating in a c-axis-tilted ScAlN film/3C-SiC substrate structure. By appropriately selecting the c-axis tilt angle and the film thickness of the ScAlN film, a high electromechanical coupling coefficient (K2) value was obtained in the second-mode RSAW (Sezawa wave). The maximum K2 value for the Sezawa wave was 8.03%, with a phase velocity of 7456 m/s and a power flow angle of 0° under the structural conditions where the K2 value was maximized. These properties offer significant advantages for achieving wide frequency bands, high operating frequencies, and ease of design for SAW resonators. The structural conditions under which good propagation characteristics were obtained in the Sezawa waves were found to coincide with the conditions that maximize the electromechanical coupling coefficient of the quasi-longitudinal wave in the ScAlN film, and a significant increase in the shear vertical component of Sezawa wave particle displacement was observed. Additionally, ScAlN films with a 40% Sc concentration can be fabricated using sputtering and molecular beam epitaxy. Recent advancements have reported the production of high-quality 3C-SiC wafers and large 3C-SiC film/silicon wafers. Therefore, the c-axis-tilted ScAlN film/3C-SiC substrate structure shows great potential as a candidate for next-generation SAW resonators.
Insights into oxygen vacancy dynamics in HfO2–ZrO2 superlattice ferroelectric films: Implications for device reliability
Authors: Wu Maokun , Cui Boyao , Wang Xuepei , Yuan Miaojia , Wu Yishan , Wen Yichen , Liu Jinhao , Zhang Ting , Ren Pengpeng , Ye Sheng , Wang Runsheng , Ji Zhigang , Huang Ru
Published: October 2024

Compared with solid solution (SS) Hf0.5Zr0.5O2, HfO2–ZrO2 superlattice (SL) ferroelectric films exhibit enhanced endurance and reduced leakage. However, so far, the underlying physical mechanism is still missing. In this work, first-principle calculations reveal that the superior reliability arises from the precise control in the spatial profile of oxygen vacancy with the stacked structure in SL in which oxygen vacancies (Vo) exhibit different formation energies and different energy profiles in Zr- and Hf-layers. However, Vo have the tendency to migrate and its suppression become critical to maintain the superiority of SL. A low annealing temperature is, therefore, suggested and validated with our fabricated SL- and SS-ferroelectric films with different annealing temperatures. This understanding can pave ways for the optimization in SL ferroelectric films.
Excess volume measurements of binary alloy liquids using electrostatic levitation: Magneto-volume effect on positive excess volume
Authors: Wang Lei , Chan Cho Yong , Lee Yun-Hee , Lee Geun Woo
Published: October 2024

In this study, we investigate the excess volume (VE) of 24 binary miscible and compound alloy melts using electrostatic levitation. Notably, Pd50X50 (X = Fe, Co, and Ni) and Pt50Fe50 solid solutions with slightly negative or zero mixing enthalpy (ΔHmix) display pronounced positive VE and significantly improved liquid stability after alloying, whereas compound alloy liquids with negative ΔHmix exhibit negative VE. Moreover, the VE of Pd50X50 and Pt50X50 consistently decreases with the increasing number of electrons in X, indicating a magneto-volume effect observed in specific heat measurements. These findings suggest that the formation of excess volume is influenced by both magnetic and thermodynamic contributions.
Wettability regulation of the electric double-layer structural evolution of complex fluids: Insights into thermodynamic and electrical properties
Authors: Chen Hongwei , Han Yiming , Wang Meng , Wei Xiang , Song Yangfan , Liu Zhuo
Published: October 2024

Understanding the structural evolution at the electrode is essential for accurate prediction of complex fluid applications, where the carbon nanotube is chosen as the carrier of CO2-ionic liquids (ILs) in electroreduction. Then, the electrical double layer with tunable wettability is investigated by molecular dynamics simulations. The competition and cooperation between van der Waals and Coulomb interactions are evaluated by examining the structural and electric characteristics. When an external potential (φ) is initiated, the co-ions are repelled from the electrode and the counter-ions compete with CO2 in the electric double layer (EDL), with different thermodynamics produced by varying the proportion of CO2/ionic liquid. As the solid–liquid interaction parameter (β) increases, more counter-ions aggregate, producing double density peaks for Tf2N− and sharply increasing the density of CO2. With increases in β and φ, the local charge density and local field potential increase, and the EDL thickness decreases. However, the location of the CO2 density layer shifts ahead to the counter-ions, weakening their shielding effect and capacitance. Using a combination of structural analysis, the first and second peaks of Tf2N− of EDL are composed of sulfonyl and trifluoromethyl, respectively. As a response, the steric hindrance of CO2 decreases, and more molecules migrate to the surface in a parallel orientation. The structural evolution is quantitatively evaluated in terms of the entropy, results show that the orientation transition is prominent in structural evolution. The coupling relation between thermodynamic and electrical properties plays a pivotal role in determining the structural evolution of complex mixtures, and these findings could benefit the advancement of ILs-based CO2 electroreduction and other complex fluid applications.
Experimental investigation of failure mechanism of fissure-filled sandstone under hydro-mechanical conditions
Authors: Du Yiteng , Duan Xinyi , Jiang Tianqi , Xing Xueyang , Ren Xiang , Chen Hongbin
Published: October 2024

Fissure fillings are critical to the hydro-mechanical properties of jointed rock masses in rock engineering. In this study, triaxial seepage tests were performed on standard cylindrical fissure-filled sandstone. The characteristics of stress–strain relationships, absorption and consumption of energy, variations in deformation resistance, and permeability evolution during the experimental process, along with the crack development observed in post-failure computed tomography scan images of the sandstone specimens were analyzed. The results demonstrate that the fillings improve the energy capacity and reduce the damage accumulation of sandstone specimens, with sand-filled specimens performing better than mud-filled specimens, especially at lower bridge angles. The fillings can reduce the depth of crack extension and lessen the influence of prefabricated fissures on sandstone failure, with this effect diminishing as the rock bridge angle increases. Permeability decreases in the pre-peak failure stage as the fillings improve the deformation resistance of the sandstone specimens. In the post-peak failure stage, the fillings and rock debris generated by the sandstone failure move within the developed fractures, causing significant fluctuations in permeability. These findings deepen the understanding of the hydro-mechanical properties of jointed rocks and provide a scientific basis for stability analysis in rock engineering.
Statistical adiabatic channel model for termolecular reactions
Authors: Pérez-Ríos J.
Published: October 2024

In this work, we present a statistical adiabatic channel model for termolecular reactions, A + B + C → Products. Our approach relies on hyperspherical coordinates, where the adiabatic channels are readily defined in the hyper-radius after averaging the hyperangular degrees of freedom. In this way, we find a general expression for termolecular rate constants. We focus on ion-neutral association reactions to test our approach’s accuracy and predictive power, finding a good agreement between theory and experiment, especially in those reactions’ temperature dependence.
Solving the Hele–Shaw flow using the Harrow–Hassidim–Lloyd algorithm on superconducting devices: A study of efficiency and challenges
Authors: Gopalakrishnan Meena Muralikrishnan , Gottiparthi Kalyana C. , Lietz Justin G. , Georgiadou Antigoni , Coello Pérez Eduardo Antonio
Published: October 2024

The development of quantum processors for practical fluid flow problems is a promising yet distant goal. Recent advances in quantum linear solvers have highlighted their potential for classical fluid dynamics. In this study, we evaluate the Harrow–Hassidim–Lloyd (HHL) quantum linear systems algorithm (QLSA) for solving the idealized Hele–Shaw flow. Our focus is on the accuracy and computational cost of the HHL solver, which we find to be sensitive to the condition number, scaling exponentially with problem size. This emphasizes the need for preconditioning to enhance the practical use of QLSAs in fluid flow applications. Moreover, we perform shots-based simulations on quantum simulators and test the HHL solver on superconducting quantum devices, where noise, large circuit depths, and gate errors limit performance. Error suppression and mitigation techniques improve accuracy, suggesting that such fluid flow problems can benchmark noise mitigation efforts. Our findings provide a foundation for future, more complex application of QLSAs in fluid flow simulations.
Large eddy simulation of micro vortex generator-controlled cavitation across multiple stages
Authors: Mou Chengqi , Che Bangxiang , Wang Yuxuan , Zhang Jiansheng , Cao Linlin , Wu Dazhuan
Published: October 2024

Micro vortex generators (mVGs) control cavitation by altering the boundary layer flow structure. This study employs the wall-adapting local eddy-viscosity large eddy simulation (WALE-LES) turbulence model combined with the Zwart–Gerber–Belamri cavitation model to conduct transient numerical simulations on the National Advisory Committee for Aeronautics 0015 baseline hydrofoil and the hydrofoil equipped with mVGs under various cavitation numbers. The proper orthogonal decomposition method and experiments verify the accuracy and consistency of these simulations regarding cavity scale. The study elucidates mechanisms by which mVGs suppress cloud cavitation at low cavitation numbers and induce vortex cavitation at high cavitation numbers. Results indicate that mVGs maintain sheet cavitation characteristics at low cavitation numbers, reducing wall pressure fluctuations and enhancing flow stability. During cavitation inception, mVG-induced vortex cavitation leads to early cavitation formation. In the sheet cavitation phase, modal energy distribution is more dispersed, while in the inception phase, energy is concentrated with significant dominant modes. Moreover, the counter-rotating vortices generated by mVGs mitigate flow separation, enhance leading-edge flow attachment stability, and reduce high-frequency vibrations caused by bubble shedding. This study significantly advances the understanding of cavitation control by accurately simulating and revealing the cavitation control mechanisms of mVGs across different stages using the WALE-LES model. The findings demonstrate that mVGs can effectively stabilize cavity structures at low cavitation numbers, reducing flow instabilities and enhancing overall hydrofoil performance. These insights will have a significant impact on the design of hydrofoils and the development of cavitation control strategies.
Arrayed CRISPRi library to suppress genes required for Schizosaccharomyces pombe viability
Authors: Ishikawa Ken , Soejima Saeko , Nishimura Takashi , Saitoh Shigeaki
Published: October 2024

The fission yeast, Schizosaccharomyces pombe, is an excellent eukaryote model organism for studying essential biological processes. Its genome contains ∼1,200 genes essential for cell viability, most of which are evolutionarily conserved. To study these essential genes, resources enabling conditional perturbation of target genes are required. Here, we constructed comprehensive arrayed libraries of plasmids and strains to knock down essential genes in S. pombe using dCas9-mediated CRISPRi. These libraries cover ∼98% of all essential genes in fission yeast. We estimate that in ∼60% of these strains, transcription of a target gene was repressed so efficiently that cell proliferation was significantly inhibited. To demonstrate the usefulness of these libraries, we performed metabolic analyses with knockdown strains and revealed flexible interaction among metabolic pathways. Libraries established in this study enable comprehensive functional analyses of essential genes in S. pombe and will facilitate the understanding of essential biological processes in eukaryotes.
Interplay of Nav1.8 and Nav1.7 channels drives neuronal hyperexcitability in neuropathic pain
Authors: Vasylyev Dmytro V. , Zhao Peng , Schulman Betsy R. , Waxman Stephen G.
Published: October 2024

While voltage-gated sodium channels Nav1.7 and Nav1.8 both contribute to electrogenesis in dorsal root ganglion (DRG) neurons, details of their interactions have remained unexplored. Here, we studied the functional contribution of Nav1.8 in DRG neurons using a dynamic clamp to express Nav1.7L848H, a gain-of-function Nav1.7 mutation that causes inherited erythromelalgia (IEM), a human genetic model of neuropathic pain, and demonstrate a profound functional interaction of Nav1.8 with Nav1.7 close to the threshold for AP generation. At the voltage threshold of −21.9 mV, we observed that Nav1.8 channel open-probability exceeded Nav1.7WT channel open-probability ninefold. Using a kinetic model of Nav1.8, we showed that a reduction of Nav1.8 current by even 25–50% increases rheobase and reduces firing probability in small DRG neurons expressing Nav1.7L848H. Nav1.8 subtraction also reduces the amplitudes of subthreshold membrane potential oscillations in these cells. Our results show that within DRG neurons that express peripheral sodium channel Nav1.7, the Nav1.8 channel amplifies excitability at a broad range of membrane voltages with a predominant effect close to the AP voltage threshold, while Nav1.7 plays a major role at voltages closer to resting membrane potential. Our data show that dynamic-clamp reduction of Nav1.8 conductance by 25–50% can reverse hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes pain in humans and suggests, more generally, that full inhibition of Nav1.8 may not be required for relief of pain due to DRG neuron hyperexcitability.
de Sitter Teukolsky waves
Authors: Harsh  , Hoque Sk Jahanur , Kashyap Sitender Pratap , Virmani Amitabh
Published: October 2024

We present de Sitter Teukolsky waves—linearised quadrupolar gravitational waves in the transverse-traceless gauge in de Sitter spacetime. In the cosmological constant Λ going to zero limit, our solutions match to Teukolsky solutions. For non-zero Λ, we compare our solutions to the wider literature, where different authors have constructed linearised gravitational perturbations in de Sitter spacetime with varied motivations. For de Sitter Teukolsky waves, we compute the energy flux across future timelike infinity

I

+

and show that it is manifestly positive.
Efficient Bayesian inference and model selection for continuous gravitational waves in pulsar timing array data
Authors: Bécsy Bence
Published: October 2024

Finding and characterizing gravitational waves from individual supermassive black hole binaries is a central goal of pulsar timing array experiments, which will require analysis methods that can be efficient on our rapidly growing datasets. Here we present a novel approach built on three key elements: (i) precalculating and interpolating expensive matrix operations; (ii) semi-analytically marginalizing over the gravitational-wave phase at the pulsars; (iii) numerically marginalizing over the pulsar distance uncertainties. With these improvements the recent NANOGrav 15 yr dataset can be analyzed in minutes after an

O

(
1
 

h

)

setup phase, instead of an analysis taking days–weeks with previous methods. The same setup can be used to efficiently analyze the dataset under any sinusoidal deterministic model. In particular, this will aid testing the binary hypothesis by allowing for efficient analysis of competing models (e.g. incoherent, monopolar, or dipolar sine wave model) and scrambled datasets for false alarm studies. The same setup can be updated in minutes for new realizations of the data, which enables large simulation studies.
The role of flow field dynamics in enhancing volatile organic compound conversion in a surface dielectric barrier discharge system
Authors: Böddecker Alexander , Passmann Maximilian , Segura Angie Natalia Torres , Bodnar Arisa , Awakowicz Felix , Oppotsch Timothy , Muhler Martin , Awakowicz Peter , Gibson Andrew R , Korolov Ihor , Mussenbrock Thomas
Published: October 2024

This study investigates the correlation between flow fields induced by a surface dielectric barrier discharge (SDBD) system and its application for the volatile organic compound gas conversion process. As a benchmark molecule, the conversion of n-butane is monitored using flame ionization detectors, while the flow field is analyzed using planar particle image velocimetry. Two individual setups are developed to facilitate both conversion measurement and investigation of induced fluid dynamics. Varying the gap distance between two SDBD electrode plates for three different n-butane mole fractions reveals local peaks in relative conversion around gap distances of 16–22 mm, indicating additional spatially dependent effects. The lowest n-butane mole fractions exhibit the highest relative conversion, while the highest n-butane mole fraction conversion yields the greatest number of converted molecules per unit time. Despite maintaining constant energy density, the relative conversion exhibits a gradual decrease with increasing distances. The results of the induced flow fields reveal distinct vortex structures at the top and bottom electrodes, which evolve in size and shape as the gap distances increase. These vortices exhibit gas velocity magnitudes approximately seven times higher than the applied external gas flow velocity. Vorticity and turbulent kinetic energy analyses provide insights intothese structures’ characteristics and their impact on gas mixing. A comparison of line profiles through the center of the vortices shows peaks in the middle gap region for the same gap distances, correlating with the observed peaks in conversion. These findings demonstrate a correlation between induced flow dynamics and the gas conversion process, bridging plasma actuator studies with the domain of chemical plasma gas conversion.
The degradation mechanism of high power S-band AlGaN/GaN HEMTs under high temperature
Authors: Yan Shumeng , Yang Tianying , Yuan Tingting , Liu Guoguo , Xu Tao , Chen Lijie , Cheng Chuan , Chen Gaopeng
Published: October 2024

The radio frequency (RF) degradation mechanism under high temperature is proposed in this paper. The saturated output power (P
sat), power added efficiency (PAE) and gain of the HEMTs deteriorate significantly under high power dissipation operation conditions, which contribute to an elevation of the junction temperature (T
j). The high T
j causes a negative shift of the threshold voltage and a reduction of electron mobility, as well as enhancing the trapping effects of the devices. As a result, the P
sat and PAE of the high-power HEMTs (P
sat = 152 W) decreased by 0.76 dB and 8.3%, respectively, which is more severe compared to low-power HEMTs (P
sat = 20 W), where P
sat and PAE reduced by 0.16 dB and 3.1% when the operation temperature was increased from 25 °C to 150 °C. By increasing the gate-to-drain distance from 1.625 to 2.175 μm, drain current stability and high temperature reverse bias reliability are improved. The results demonstrate that the trapping effect can be suppressed by decreasing the electric field under the gate; therefore, the RF output characteristics are boosted by 1.2 W, 1 dB and 2.6% for a device with gate width of 11.52 mm.
Study lepton flavor violation

B

0

⃗

l

i

±

l

j

∓

within the mass insertion approximation
Authors: Wang Yi-Tong , Ma Jiao , Han Xing-Yu , Long Xin-Xin , Wang Tong-Tong , Zhang Hai-Bin , Zhao Shu-Min
Published: October 2024

We study lepton flavor violating (LFV) decays

B

0

→

l

i

±

l

j

∓

(B
0 → eμ, B
0 → eτ and B
0 → μτ) in the U(1)
X
SSM (SSM is acronym for the supersymmetric standard model), which is the U(1)
X
extension of the minimal supersymmetric standard model (MSSM). The local gauge group of U(1)
X
SSM is SU(3)
C
 ×SU(2)
L
 × U(1)
Y
 × U(1)
X
. These processes (B
0 → eμ, B
0 → eτ and B
0 → μτ) are strictly forbidden in the standard model, but these LFV decays are a signal of new physics. We use the mass insertion approximation to find sensitive parameters that directly influence the result of the branching ratio of LFV decay

B

d

→

l

i

±

l

j

∓

.

Combined with the latest experimental results, we analyze the relationship between different sensitive parameters and the branching ratios of the three processes. According to the numerical analysis, these elements are very restricted from the non observation of charged lepton flavor violation (CLFV).
Triaxial deformation, shell structure, shell corrections and the connection to alpha-clustering in nuclei
Authors: Clark Georgina , Taylor Holly , Freer Martin
Published: October 2024

We explore the connection between the appearance of quasi-stable structures in mean-field type calculations, which arise as a result of the evolution of the underlying shell structure as a function of deformation, and α-clustering in light even–even nuclei. The Nilsson–Strutinsky mean-field approach employs a macroscopic liquid-drop whose energy is modified by a shell correction term derived using the Strutinsky method. This method reflects the variations in the energies of the single-particle states with deformation. As such, there is no obvious connection to clustering. Here we use the changing level scheme of the deformed harmonic oscillator as a function of triaxial deformation to fully explore the variation in stability of α-cluster structures in light even–even nuclei. The energies of the harmonic oscillator levels are used to deduce the energy required to disrupt the α-cluster as a function of the triaxial deformation. We find that there is good agreement between variations in the shell correction energy in the mean-field method and the energy required to disrupt the α-cluster. This provides a necessary link between understanding of the appearance of quasi-stable α-cluster structures and quasi-stable shapes appearing in mean-field calculations.
Electronic, optical and thermoelectric behavior of KCuX (X = S, Se, Te) monolayers
Authors: Gupta Neelam , Kumar Shubham , Rani Shivani , Kumari Puja , Kar Subhasmita , Ahuja Rajeev , Jyoti Ray Soumya
Published: October 2024

In the past few decades, two-dimensional materials gained huge deliberation due to their outstanding electronic and heat transport properties. These materials have effective applications in many areas such as photodetectors, battery electrodes, thermoelectrics, etc. In this work, we have calculated structural, electronic, optical, and thermoelectric (TE) properties of KCuX (X = S, Se, Te) monolayers (MLs) with the help of first-principles-based calculations and semi-classical Boltzmann transport equation. The phonon dispersion calculations demonstrate the dynamical stability of the KCuX (X = S, Se, Te) MLs. Our results show that the MLs of KCuX (X = S, Se, Te) are semiconductors with band gaps of 0.193 eV, 0.26 eV, and 1.001 eV respectively, and therefore they are suitable for photovoltaic applications. The optical analysis illustrates that the maximum absorption peaks of the KCuX (X = S, Se, Te) MLs are located in the visible and ultraviolet regions, which may serve as a promising candidate for designing advanced optoelectronic devices. Furthermore, thermoelectric properties of the KCuS and KCuSe MLs, including Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor and figure of merit are calculated at different temperatures of 300 K, 600 K, and 800 K. Additionally, we also focus on the analysis of Grüneisen parameter and various scattering rates to further explain their ultra-low thermal conductivity. Our results show that KCuS and KCuSe possess ultra-low lattice thermal conductivity value of 0.15

W

m

−
1

K

−
1

and 0.06

W

m

−
1

K

−
1

respectively, which is lower than those of recently reported KAgSe (0.26

W

m

−
1

K

−
1

at 300 K) and TlCuSe (0.44

W

m

−
1

K

−
1

at 300 K), indicating towards the large value of ZT. These materials are found to possess desirable thermoelectric and optical properties, making them suitable candidates for efficient thermoelectric and optoelectronic device applications.
Synchronous decomposition match-reassigning transform and its application in planetary gearbox fault diagnosis
Authors: Wu Hengshan , Zhi Shaodan , Fang Qiqiang , Liu Yang , Wang Tianyang , Cheng Weidong , Chu Fulei
Published: October 2024

Under time-varying operating conditions, the instantaneous frequency (IF) of the vibration signal of the planetary gearbox exhibits non-stationary time-varying closely spaced characteristics as well as non-proportional and non-synchronous characteristics. This in turn leads to challenges for traditional time-frequency analysis (TFA) methods to accurately identify its fault features and obtain accurate time-frequency representations (TFR). To address this challenge, in this study, a TFA method is proposed based on Synchronous Decomposition Match-Reassigning Transform (SDMRT). First, the successive variational mode decomposition (SVMD) is used to adaptively separate non-synchronous frequency components in the original vibration signal. Second, the chirp rate (CR) describing the signal harmonic structure is used to synchronously match each frequency component, obtaining the TFR corresponding to each component. Third, all TFRs are merged to obtain a complete TFA result. Finally, the energy spread is re-aggregated to the ridge of the IF using the reassignment principle, resulting in a new frequency estimation operator termed the Synchronous Decomposition Match-Reassigning Operator (SDMRO). SDMRT can adaptively separate non-proportional and non-synchronous IFs and realize precise matching of time-varying closely spaced IFs, thereby completing the TFR of the vibration signal generated by the planetary gearbox. By analyzing simulated signals and measured vibration signals from planetary gearboxes, Rényi entropy and IF estimation errors of SDMRT correspond to 12.14% and 0.59%, respectively. The energy concentration degree and IF estimation results are significantly better than other TFA methods, which proves the effectiveness and superiority of SDMRT.
GNSS-assisted optimal alignment method for low-cost SINS motion of vehicle
Authors: Yan Yuqian , Si Yongbo , Chen Guangwu , Zhou Xin , Li Pengpeng
Published: October 2024

To improve the alignment accuracy and environmental applicability of the micro-electromechanical system (MEMS)-based strapdown inertial navigation system (SINS), this study proposes a global navigation satellite system (GNSS)-assisted multi-vector determination of the attitude optimal indirect coarse alignment. Using the inertial information output from the inertial measurement unit and the velocity information from the GNSS, a simplified velocity observation vector is constructed and the velocity lever arm stemming from the mounting position inconsistencies of the GNSS and SINS is fed back into the velocity of the carrier system. When constructing the observation vectors, the integration interval is shortened by reconstructing the two-vector integration formula for reducing the cumulative error of the inertial device. The attitude matrix problem is defined as the Wahba problem, which is solved using the singular value decomposition method. Based on the relationship between gyro zero bias and misalignment angle, the corresponding state and measurement equations are designed. Furthermore, owing to the measurement noise uncertainty, the adaptive traceless Kalman filtering algorithm is introduced to realize the effective adaptation processing of the measurement noise. More accurate attitude matrix estimates are obtained by continuously correcting the carrier system transformation matrix. The running car experiment results show that the proposed method exhibits higher alignment accuracy and environmental applicability than the current MEMS strapdown inertial navigation coarse alignment method and the traditional optimization-based alignment method.
Compressed sensing with smooth L0 constraints for moving force identification from bridge response measurements
Authors: Liang Yi , Hou Zhilong , Yu Ling
Published: October 2024

Compressed sensing (CS), as an emerging information sampling technique, has been successfully applied in the field of moving force identification (MFI). However, existing MFI CS models often fail to obtain the optimal sparse solutions and frequently underestimate the amplitude of local impact forces. To effectively address this issue, a new CS method is proposed for MFI based on smooth L0 norm constraints and bridge response measurements. Firstly, a smooth function is used to approximate the L0 norm, establishing a noise CS reconstruction model for MFI. The introduction of the smoothing function can locally convexify the original MFI problem and enhance the smoothness and differentiability of the objective function, making the optimization problem easier to solve. Subsequently, the Polak–Ribiere–Polyak formula is adopted to point the descent direction of the new objective function, and the sparse solution is iteratively advanced through the conjugate gradient algorithm. Finally, the applicability and feasibility of the proposed method is confirmed by numerical simulations and vehicle–bridge interaction tests, respectively. The results show that the proposed method can accurately identify moving forces from limited measurements of bridge responses. Compared with existing methods, it can provide more precise sparse solutions with higher robustness to measurement noises, and address the issue of underestimating on the amplitude of local impact forces, which is expected to enhance the performance and in-situ applicability of MFI.
Enhancing machine learning multi-class fault detection in electric motors through entropy-based analysis
Authors: Palaiologou Ilias , Falekas Georgios , Antonino-Daviu Jose A , Karlis Athanasios
Published: October 2024

In the field of electric motor maintenance, this study introduces a transformative approach by integrating entropy-based algorithms with machine learning for enhanced multi-class fault detection. Employing Shannon, Renyi, and Tsallis entropy algorithms on standard fault detection measurements, the research significantly advances predictive maintenance strategies through a robust, early-indication, system-agnostic analysis. Detailed examination is conducted, comparing results derived from datasets that include statistical features (excluding entropy) against the proposed entropy-based datasets, when applied to a multi-layer perceptron classifier (MLPC). Optimization of the MLPC and all compared algorithms’ hyperparameters is done using the state-of-the-art Optuna tool to dynamically explore each search space, ensuring that each methodology performs adequately in a timely fashion while allowing for adaptation. The results showcase significant enhancement in classification accuracy of diverse electric motor operational states, facilitating the differentiation between healthy and various levels of fault conditions under assorted load scenarios. Computational analyses reveal favorable results related to execution time and memory overhead, thereby supporting the practicality in operations constrained by memory resources. Validation of the approach is achieved through laboratory experiments on a purpose-built test bench. Versatility of entropy-based measures through their proposed utilization in diverse fault indications is achieved by a demonstration in the field of mechanical fault detection with a focus on bearing faults through well-respected datasets.
Unconventional coil shape design of eddy current sensors and the effect of shape parameters on the micro/nano-scale metal film thickness measurement performance
Authors: Li Hongkai , Lu Xinghao , Wang Jinlong , Zhang Tong
Published: October 2024

The thickness of metal film is a critical parameter, especially in micro/nano-manufacturing, where high-precision measurement is essential. The eddy current method, a non-destructive testing technique, is well-suited for in-situ measurement of micro/nano-scale metal film thickness due to its superior performance. However, enhancing the measurement capabilities of eddy current sensors remains a significant challenge. In practical applications, thickness sensitivity and spatial resolution are two key performance indicators of eddy current sensors, and improving both simultaneously is difficult. While the sensitive element (coil) of an eddy current sensor has a substantial impact on thickness sensitivity, its effect on spatial resolution has received less attention. This study establishes an eddy current coil model based on electromagnetic field, defining both thickness sensitivity and spatial resolution in the context of micro/nano-scale metal film thickness measurement. Two unconventional coil shapes are introduced, contrasting with the traditional cylindrical design, to investigate the effect of coil shape parameters, specifically the spatial distribution of the coil turns, on the key performance indicators. Simulation results are corroborated through experimental validation. Based on a series of calculations and analyses, an optimization method for coil shape parameters is proposed using a defined comparison factor that balances both thickness sensitivity and spatial resolution, which offers a promising approach for improving coil shape design.
Electric field simulation, structure and properties of nanofiber- coated yarn prepared by multi-needle water bath electrospinning
Authors: Wang Xiaohu , Zhou Xinru , Zhao Xiaoman , Han Xiao , Hong Jianhan
Published: October 2024

To address the issue of low yield in the preparation of nanofiber materials using single-needle electrospinning technology, multi-needle electrospinning technology has emerged as a crucial solution for mass production. However, the mutual interference of multiple electric fields between the needles can cause significant randomness in the morphology of the produced nanofibers. To better predict the influence of electric field distribution on nanofiber morphology, simulation analysis of the multi-needle arrangement was conducted using finite element analysis (FEA) software. Nanofiber-coated yarn was produced continuously with the core yarn rotating. The water bath was utilized as the receiver of nanofibers on self-made water bath electrospinning equipment. The electric field distribution and mutual interference under seven different needle arrangements was simulated and analyzed by FEA software ANSYS Maxwell. The results indicated that when the needles were arranged diagonally in a staggered pattern and directly above the core yarn, the simulated electric field distribution was relatively uniform, with less mutual interference. The produced nanofibers exhibited a finer diameter and the diameter distribution was more concentrated. In addition, the nanofiber coating showed higher crystallinity and better mechanical properties.
MoS2 high temperature sensitive element with a single Si3N4 protective layer
Authors: Kong Lingbing , Li Yuning , Wang Yuqiang , Deng Tao
Published: October 2024

Temperature sensors have extensive applications in industrial production, defense, and military sectors. However, conventional temperature sensors are limited to operating temperatures below 200 °C and are unsuitable for detecting extremely high temperatures. In this paper, a method for thermal protection of molybdenum disulfide (MoS2) films is proposed and a MoS2 high temperature sensor is prepared. By depositing silicon nitride (Si3N4) films onto monolayer MoS2, not only is the issue of high-temperature oxidation effectively addressed, but also the prevention of contamination by impurities that could potentially compromise the performance of MoS2. Moreover, the width of the Schottky barrier of metal/MoS2 is reduced by using plasma-enhanced chemical vapor deposition of 400 nm Si3N4 to form an ohmic contact, which improves the electrical performance of the device by three orders of magnitude. The sensor exhibits a positive temperature coefficient measurement range of 25 °C–550 °C, with a maximum temperature coefficient of resistance of 0.89%·°C−1. The thermal protection method proposed in this paper provides a new idea for the fabrication of high-temperature sensors, which is expected to be applied in the high-temperature field.
Convex integration solution of two-dimensional hyperbolic Navier–Stokes equations*
Authors: Wu Jiahong , Yamazaki Kazuo
Published: October 2024

Hyperbolic Navier–Stokes equations replace the heat operator within the Navier–Stokes equations with a damped wave operator. Due to this second-order temporal derivative term, there exist no known bounded quantities for its solution; consequently, various standard results for the Navier–Stokes equations such as the global existence of a weak solution, that is typically constructed via Galerkin approximation, are absent in the literature. In this manuscript, we employ the technique of convex integration on the two-dimensional hyperbolic Navier–Stokes equations to construct a weak solution with prescribed energy and thereby prove its non-uniqueness. The main difficulty is the second-order temporal derivative term, which is too singular to be estimated as a linear error. One of our novel ideas is to use the time integral of the temporal corrector perturbation of the Navier–Stokes equations as the temporal corrector perturbation for the hyperbolic Navier–Stokes equations.