bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting Postoperative Pain and Opioid Use with Machine Learning Applied to Longitudinal Electronic Health Record and Wearable Data
Authors: Soley Nidhi , Speed Traci J. , Xie Anping , Taylor Casey Overby
Published: May 2024

Background Managing acute postoperative pain and minimizing chronic opioid use are crucial for patient recovery and long-term well-being.

Objectives This study explored using preoperative electronic health record (EHR) and wearable device data for machine-learning models that predict postoperative acute pain and chronic opioid use.

Methods The study cohort consisted of approximately 347 All of Us Research Program participants who underwent one of eight surgical procedures and shared EHR and wearable device data. We developed four machine learning models and used the Shapley additive explanations (SHAP) technique to identify the most relevant predictors of acute pain and chronic opioid use.

Results The stacking ensemble model achieved the highest accuracy in predicting acute pain (0.68) and chronic opioid use (0.89). The area under the curve score for severe pain versus other pain was highest (0.88) when predicting acute postoperative pain. Values of logistic regression, random forest, extreme gradient boosting, and stacking ensemble ranged from 0.74 to 0.90 when predicting postoperative chronic opioid use. Variables from wearable devices played a prominent role in predicting both outcomes.

Conclusion SHAP detection of individual risk factors for severe pain can help health care providers tailor pain management plans. Accurate prediction of postoperative chronic opioid use before surgery can help mitigate the risk for the outcomes we studied. Prediction can also reduce the chances of opioid overuse and dependence. Such mitigation can promote safer and more effective pain control for patients during their recovery.
Neurological Findings and a Brief Review of the Current Literature in a Severe Case of Aicardi-Goutières Syndrome Due to an IFIH1 Mutation
Authors: Železnik Mojca , Vesnaver Tina Vipotnik , Neubauer David , Soltirovska-Šalamon Aneta
Published: May 2024

Aicardi-Goutières syndrome (AGS) is a rare genetic early-onset progressive encephalopathy with variable clinical manifestations. The IFIH1 mutation has been confirmed to be responsible for type I interferon production and activation of the Janus kinase signaling pathway. We herein stress neurological observations and neuroimaging findings in a severe case report of an infant with AGS type 7 due to an IFIH1 mutation who was diagnosed in the first month of life. We also review neurological characteristics of IFIH1 mutations through recent literature.
A Prospective Study to Evaluate the Prevalence of Microsatellite Instability in Endometrial Carcinoma by using Immunohistochemistry for Mismatch Repair Proteins as a Surrogate Marker
Authors: Solanki Prithviraj K. , Mandolkar Mahesh , Kulkarni Padmaj
Published: May 2024

Aim Use of immunohistochemistry for mismatch repair (MMR) proteins to identify the prevalence of microsatellite instability (MSI) in cases of endometrial carcinoma and its subsequent correlation with various histopathological parameters.

Materials and Methods The expression of MMR proteins, viz PMS2, MLH1, MSH2, and MSH6, were assessed in 114 endometrial cancer cases by immunohistochemistry using Dako EnVision FLEX system, on paraffin blocks of tumor tissue fixed in 10% formalin.

Results We studied 114 endometrial cases for MMR protein expression, of which the majority were of endometrioid histologic subtype (n = 93, 81.6%), whereas the remainder comprised serous carcinoma (n = 12, 10.5%), clear cell carcinoma (n = 1, 0.9%), carcinosarcoma (n = 5, 4.4%), and dedifferentiated uterine carcinoma (n = 3, 2.6%). Twenty-one (18%) of these cases were found to be deficient for MMR proteins, of which 20 were of endometrioid histologic subtype and only 1 was dedifferentiated uterine carcinoma. Loss of MMR protein expression occurred in pairs of either PMS2 and MLH1 or MSH2 and MSH6.

Conclusion MSI is one of the major molecular pathways contributing to tumorigenesis in endometrial carcinomas. Immunohistochemistry for MMR proteins is a highly sensitive and cost-effective alternative for molecular testing for MSI. It is also a great tool for screening patients for Lynch syndrome. Immunohistochemical testing for MMR should be offered to all patients of endometrial cancers.
Assessment of Preoperative Anxiety Utilizing Amsterdam Preoperative Anxiety and Information Scale in Patients Undergoing Intracranial Tumor Surgery: An Exploratory Study
Authors: Chandra Vikram , Goel Nishant , Kumari Ranjeeta , Agrawal Sanjay
Published: May 2024

Background Preoperative anxiety in neurosurgical patients is high due to life-threatening illness and uncertainty of the surgical outcome. This study assessed preoperative anxiety and its influencing factors in patients undergoing intracranial tumor surgeries utilizing the Amsterdam Preoperative Anxiety and Information Scale (APAIS).

Methods One-hundred twenty patients, 18 to 65 years of age, of either sex, American Society of Anesthesiologists (ASA) grades I/II posted for elective craniotomy and tumor excision, were selected for the study. Various components of the APAIS were explained, and the level of anxiety and need for information were noted. The level of anxiety and depression by HADS (Hospital Anxiety and Depression Scale) score was also evaluated.

Results The mean age was 38.00 ± 12.15 years. About 57.5% of the patients were male. Eighteen (15%) patients had an educational qualification of class 10, 60(50%) of 10 + 2, 36 (30%) were graduates, and 6 (5%) had a postgraduate qualification.

The mean APAIS for total anxiety was 11.10 ± 1.79; the score for need for information was 6.28 ± 1.61. Mean total anxiety scores were higher in female patients (11.96 vs. 10.46, p < 0.001). Higher anxiety was observed in ASA status I patients (11.33 vs. 10.539 ASA I vs. II, p = 0.020). Significantly higher anxiety was observed in patients educated till class 10 (p = 0.012). A significantly higher need for information was observed in postgraduates (p = 0.012). Eighty (66.7%) patients had clinical anxiety, and 35 (29.2%) had clinical depression on the HADS score.

Conclusion Neurosurgical patients have higher anxiety due to intracranial pathology, site of surgery, and unpredictability of outcome. Demographic and clinical variables do affect anxiety levels.
Volunteer translators in non-governmental organizations: exploring their identity and power through discourse analysis
Authors: Sánchez Ramos María del Mar
Published: May 2024

The need for immediate communication in a world characterized by an ever-increasing flow of information has led to a rapid increase in volunteer translation in recent decades. While previous studies have focused on aspects such as volunteer translators’ motivation and the attendant ethical issues of voluntary translation, comparatively little research has explored the phenomenon from a discursive perspective. The research reported in this article explored the discursive construction of the volunteer translator in non-governmental organizations (NGOs) active in Spain using critical discourse analysis. Drawn from analysis of 25 semi-structured individual interviews with volunteer translators in five different NGOs, the findings reveal that volunteer translators are seen either as an agent and actor of social change who facilitates communication and possesses a strong sense of identity and social status, or as someone who is interfering in a sector traditionally limited to professional translators and who consequently has a weaker sense of identity and social status. This suggests that the role of the volunteer translator currently lacks definition, and that further research is needed to better understand the relationship between volunteer and professional translators in the 21st century.
More romantic or more realistic: trajectories and influencing factors of romantic love among Chinese college students from entering college to graduation
Authors: Liu Xinqiao , Ji Xinyu , Zhang Yifan
Published: May 2024

College is a significant transition in the growth of individuals, and romantic relationships play an important role in the future development of individuals. Understanding young people’s attitudes toward love is helpful for formulating strategies to guide them to form correct attitudes toward love, promote the formation of positive and healthy attitudes toward marriage and life. This study aimed to explore the trajectories of college students’ attitudes toward love, reveal the development law of their attitudes toward love, and identify the influencing factors that lead to changes in their attitudes toward love. Descriptive and correlation analyses were performed on participants’ attitudes toward love, followed by utilization of a growth mixture model to explore latent trajectory classes and a multinomial logistic regression model to analyze influencing factors across trajectories.The results indicated that romantic attitudes could be divided into three groups: “high-increasing”, “low-decreasing” and “low-increasing”, and realistic attitudes could be divided into three groups: “high-increasing”, “low-increasing” and “high-decreasing”. Gender, major, extroversion, and hometown location were factors influencing whether students fell into different trajectory classes. Overall, society and colleges should pay more attention to changes in college students’ attitudes toward love, provide timely intervention and guidance, and prevent them from suffering from behavioral, physical, and psychological problems.
Voltage-modulated polymer nanopore field-effect transistor for multi-sized nanoparticle detection
Authors: Zhou Feng , Li Lin , Xue Qiannan
Published: May 2024

Solid-state nanopores offer a range of distinct advantages over biological nanopores, such as structural diversity and greater stability and durability; this makes them highly promising for high-resolution nanoparticle sensing. Biological nanopores can exhibit gating characteristics with stress-responsive switches and can demonstrate specificity toward particular molecules. Drawing inspiration from biological nanopores, this paper introduces a novel polymer nanopore with field-effect characteristics, leveraging a conductive polymer in its construction to showcase intriguing gating behavior. Notably, in this device, the polymer layer serves as the gate, enabling precise control over the source–drain current response inside and outside the pore by simply adjusting the gate voltage. This unique feature allows fine-tuning of the nanopore’s sensitivity to nanoparticles of varying sizes and facilitates its operation in multiple modes. Experimental results reveal that the developed polymer nanopore field-effect transistor demonstrates remarkable selectivity in detecting nanoparticles of various sizes under different applied voltages. The proposed single device demonstrates the exceptional ability to detect multiple types of nanoparticle, showcasing its immense potential for a wide range of applications in biological-particle analysis and medical diagnostics.
A comparative review of time-resolved x-ray and electron scattering to probe structural dynamics
Authors: Lee Yunbeom , Oang Key Young , Kim Doyeong , Ihee Hyotcherl
Published: May 2024

The structure of molecules, particularly the dynamic changes in structure, plays an essential role in understanding physical and chemical phenomena. Time-resolved (TR) scattering techniques serve as crucial experimental tools for studying structural dynamics, offering direct sensitivity to molecular structures through scattering signals. Over the past decade, the advent of x-ray free-electron lasers (XFELs) and mega-electron-volt ultrafast electron diffraction (MeV-UED) facilities has ushered TR scattering experiments into a new era, garnering significant attention. In this review, we delve into the basic principles of TR scattering experiments, especially focusing on those that employ x-rays and electrons. We highlight the variations in experimental conditions when employing x-rays vs electrons and discuss their complementarity. Additionally, cutting-edge XFELs and MeV-UED facilities for TR x-ray and electron scattering experiments and the experiments performed at those facilities are reviewed. As new facilities are constructed and existing ones undergo upgrades, the landscape for TR x-ray and electron scattering experiments is poised for further expansion. Through this review, we aim to facilitate the effective utilization of these emerging opportunities, assisting researchers in delving deeper into the intricate dynamics of molecular structures.
Modeling of tungsten impurity transport and distribution in EAST based on multi-fluid and kinetic Monte Carlo simulations
Authors: Wen Ziyang , Chen YiPing , Zhang Ling
Published: May 2024

In recent years, the materials of plasma facing components, such as divertor target plates, domes, and outer walls of tokamaks, such as ASDEX Upgrade, WEST, JET, EAST, and ITER, have been changed from carbon to tungsten because of its lower erosion and tritium retention rates. Impurities are produced by interactions between the plasma and the first wall. This study provides an investigation to simulate the transport and distribution of tungsten impurities in the edge plasma on EAST. The 2D multi-fluid edge plasma transport code SOLPS-ITER and 2D kinetic Monte Carlo impurity transport code DIVIMP were used in the simulations. The multi-fluid model in SOLPS-ITER and the kinetic Monte Carlo model in DIVIMP were employed to treat tungsten impurity ions. The 2D density contour distributions in the computational region and the 1D density radial profiles at the inner and outer midplanes of tungsten impurity particles with ionization states (W0–W+74) and the total tungsten particles with all charge states were obtained. With the heating power 1.5 MW and the line-averaged plasma density 2 × 1019 m−3, the results from SOLPS-ITER and DIVIMP show that the maximum density of tungsten ion with single ionization state is about 1014 m−3 and the total density of tungsten impurities with all charge states is about 1015 m−3 at the core boundary. To the best of our knowledge, the simulation results from SOLPS-ITER and DIVIMP are compared for the first time to benchmark SOLPS-ITER with the multi-fluid mode and DIVIMP with the kinetic model for tungsten impurity transport. The density distributions of tungsten impurities with different ionization states from SOLPS-ITER and DIVIMP are highly similar, and good agreement can be found under similar conditions involved in the calculation. From the comparison benchmark between SOLPS-ITER and DIVIMP for tungsten impurity transport, it can be concluded that the impurity transport approximation used by DIVIMP is good.
Mixed-mode oscillations in a three-timescale coupled Morris–Lecar system
Authors: Phan Ngoc Anh , Wang Yangyang
Published: May 2024

Mixed-mode oscillations (MMOs) are complex oscillatory behaviors of multiple-timescale dynamical systems in which there is an alternation of large-amplitude and small-amplitude oscillations. It is well known that MMOs in two-timescale systems can arise either from a canard mechanism associated with folded node singularities or a delayed Andronov–Hopf bifurcation (DHB) of the fast subsystem. While MMOs in two-timescale systems have been extensively studied, less is known regarding MMOs emerging in three-timescale systems. In this work, we examine the mechanisms of MMOs in coupled Morris–Lecar neurons with three distinct timescales. We investigate two kinds of MMOs occurring in the presence of a singularity known as canard-delayed-Hopf (CDH) and in cases where CDH is absent. In both cases, we examine how features and mechanisms of MMOs vary with respect to variations in timescales. Our analysis reveals that MMOs supported by CDH demonstrate significantly stronger robustness than those in its absence. Moreover, we show that the mere presence of CDH does not guarantee the occurrence of MMOs. This work yields important insights into conditions under which the two separate mechanisms in two-timescale context, canard and DHB, can interact in a three-timescale setting and produce more robust MMOs, particularly against timescale variations.
Ion kinetic effects on the formation of intense laser-driven shock waves
Authors: Xu Y. P. , Zhang W. S. , Yao P. L. , Liu Q. K. , Luo H. , Li S. , Cai H. B. , Zhu S. P.
Published: May 2024

The ion kinetic effect on the formation of intense laser-driven collisional shock waves is investigated via hybrid fluid-particle-in-cell simulations. It is found that the ion heat flux dominates the shock formation, which is considerably larger than the electron heat flux in the shock region. The rise of the temperature due to the laser energy deposition drives a heatwave into the overdense plasma, creating an electron–ion energy exchange zone between the critical surface and heat wave front. The heated ions, which are generated at the electron–ion energy exchange zone via the friction force, are found to travel to the high-density region and cause a tail distribution gain. Despite the small quantity, the heated tail ions contribute most of the ion heat flux during the shock formation. Additionally, as the electron heat flux decreases, the population of the heated tail ions is reduced, leading to a fall in the ion heat flux. This results in the delay or even suppression of the shock formation, because the ions are in a non-equilibrium state in the vicinity of the shock region, the ratio of the downstream ion temperature to the upstream ion temperature tends to a modestly decrease in comparison to the theory. The study provides a clear picture of the formation process of laser-driven shock waves.
Spot size measurement of a deuterium–tritium dense plasma focus using neutron radiography
Authors: Tafoya L. , Geppert-Kleinrath V. , Allison J. , Baker S. , Bundgaard J. , Freeman M. , Hayes-Sterbenz A. , Jungman G. , Li H. , Li S. , Lowe D. , Tybo J. , Wilde C.
Published: May 2024

Neutron radiography is a technique uniquely suited to applications in nuclear diagnostics, non-destructive testing, and subcritical experiments. The spatial resolution of neutron radiographs is degraded by optical blur in the imaging system and the neutron source size, where the ideal source is point-like to optimize the point-spread function. A potential neutron source for radiography is the dense plasma focus (DPF), a coaxial Z-pinch that produces thermonuclear and beam-target neutrons. To assess if the source size is suitable for radiography, a neutron imaging system was used to measure the source size of the 4 MA Sodium DPF at the Nevada National Security Site operating with deuterium–tritium gas-fill. The source size was measured using the edge-spread function of tungsten objects, each having a rolled (convex) edge. The spot size was found to be 7–12 mm full-width at half-max (FWHM) assuming a Gaussian source, though comparison is presented for Lorentzian and Bennett distributions. The average FWHM was found to be 8.6 ± 1.2 mm vertically and 10.8 ± 1.2 mm horizontally with respect to the image plane, averaging over varied edges and alignments. The results were sensitive to source alignment and edge metrology, which introduced notable uncertainties. These results are consistent with separate experimental measurements as well as magnetohydrodynamics simulations of this DPF, which suggest that neutron production can originate from pinches ∼5–7 mm off-axis. These results suggest that the DPF should be used for radiography at low magnification (M < 1) where spot size does not dominate spatial blur.
Optical response and temperature shielding coatings using tri-layer structure composed of titania/silica/titania
Authors: Yepuri Venkatesh , Balamurugan K.
Published: May 2024

The fabrication of metamaterials with inspiration from nature paved the door for the creation of revolutionary passive and active devices. Butterfly wings are one of them, and their multilayered structure motivated nanotechnologists, physicists, and other optoelectronic and photonic engineers to develop photonic crystals, dielectric reflectors, and Bragg reflectors for use in visible light communication, solar cells, and other photonic and optoelectronic applications. We report the sol–gel spin coating of a dielectric reflector on the glass substrate, an optical passive component consisting of titania and silica thin films for infrared radiation reflection. Individual thin films of titania and silica on glass substrates were studied using an x-ray diffractometer, which indicated anatase of titania and the amorphous nature of silica at a Bragg angle of 25° with a sharp and wide peak, respectively. The multilayer structure of titania/silica/titania was further investigated using Fourier transform infrared spectroscopy, which revealed the presence of Ti–O–Ti and Si–O–Si vibrational bonds at wavenumbers 546 and 973 cm−1, respectively, as well as the presence of Ti–O–Si vibrational bond at 1100 cm−1. The thickness of the multilayer titania/silica/titania was measured using a cross-sectional field emission scanning electron microscope (FESEM) and found to be 160/240/160 nm, respectively. Finally, reflection investigation on the multilayer structure using ultraviolet–visible–near-infrared spectroscopy validated the reflection of the infrared spectrum area by around 70% and showed to be beneficial for temperature shielding applications on glass furnishings.
Radiation hardness of semiconductor laser diodes for space communication
Authors: Li Manyang , Shen Chao , Sun Zhenyu , Xu Bo , Zhao Chao , Wang Zhanguo
Published: May 2024

Semiconductor laser diodes (LDs), with merits of little volume, lightweight, low power consumption, ease of modulation, and high data rates, are great candidates for space laser communications. However, operating in a radiation environment can result in various damages to LDs. Hence, the growing focus on satellite laser communications necessitates LDs with improved radiation hardness. This review covers the efforts made in investigating the radiation effects on LDs induced by various types of radiation, including neutrons, γ-rays, protons, electrons, and other radiation particles. The conditions of radiation experiments and the behaviors and mechanisms of the degradation of LD material and device performance after being radiated are surveyed and discussed. It has been revealed that quantum dot (QD) LDs typically exhibit superior radiation tolerance compared to quantum well LDs or LDs with bulk active layers due to the enhanced confinement of carriers and reduced active areas in QD LDs, indicating significant potential for space applications. Furthermore, current challenges and issues in this field are discussed and addressed, providing a perspective and outlook for further research. Our review aims to guide the development of suitable light sources for future space laser communications, fostering high-performance satellite communications networks.
Analysis of composition and dynamics of the plasma plume emitted by a 1 J pulsed plasma thruster fed with polytetrafluoroethylene and determination of thruster efficiency components
Authors: Jakubczak Maciej , Jardin Agnieszka , Kurzyna Jacek
Published: May 2024

The plasma plume of a 1 J pulsed plasma thruster fed with polytetrafluoroethylene (PTFE) was studied with electric probes to obtain the shape and composition of the beam of ejected ions. Two ion diagnostic tools—Faraday cup (FC) and retarding potential analyzer (RPA), were employed together with a time-of-flight approach. The FC was used to obtain spatially and time-resolved data of the mean ion charge expelled from the thruster in each pulse. With the RPA the beam was examined for the presence of specific ion species. The results of this investigation indicated the presence of both elements of PTFE in the beam—fluorine and carbon as well as copper from the discharge electrodes. Fluorine ions (identified in charge-states from F+ up to F6+) constituted the majority of ions in the plume with only trace amounts of C+ detected, which raises the question on the whereabouts of the remaining carbon. Energy distribution and relative abundance of fluorine ion species on axis were retrieved and it was found that F2+ constitutes over 40% of the plasma—in both quantity and energy fraction. Angular profiles of ion charge density, apart from the expected azimuthal asymmetry, showed heightened flux of ions in the area shaded by the discharge electrodes. The results obtained from both diagnostics allowed us to calculate propellant utilization, beam divergence, and energy utilization. By combining this information, the total thruster efficiency was retrieved, which turned out to be comparable to the value obtained from impulse bit measurements.
Simulating CO2 diffusivity in rigid and flexible Mg-MOF-74 with machine-learning force fields
Authors: Zheng Bowen , Gu Grace X. , Santos Carine dos , Neumann Barros Ferreira Rodrigo , Steiner Mathias , Luan Binquan
Published: May 2024

The flexibility of metal–organic frameworks (MOFs) affects their gas adsorption and diffusion properties. However, reliable force fields for simulating flexible MOFs are lacking. As a result, most atomistic simulations so far have been carried out assuming rigid MOFs, which inevitably overestimates the gas adsorption energy. Here, we show that this issue can be addressed by applying a machine-learning potential, trained on quantum chemistry data, to atomistic simulations. We find that inclusion of flexibility is particularly important for simulating CO2 chemisorption in MOFs with coordinatively unsaturated metal sites. Specifically, we demonstrate that the diffusion of CO2 in a flexible Mg-MOF-74 structure is about one order of magnitude faster than in a rigid one, challenging the rigid-MOF assumption in previous simulations.
The development of thermodynamically consistent and physics-informed equation-of-state model through machine learning
Authors: Hinz J. , Yu Dayou , Pandey Deep Shankar , Sapkota Hitesh , Yu Qi , Mihaylov D. I. , Karasiev V. V. , Hu S. X.
Published: May 2024

Ab initio molecular dynamics (AIMD) simulations have become an important tool used in the construction of equations of state (EOS) tables for warm dense matter. Due to computational costs, only a limited number of system state conditions can be simulated, and the remaining EOS surface must be interpolated for use in radiation-hydrodynamic simulations of experiments. In this work, we develop a thermodynamically consistent EOS model that utilizes a physics-informed machine learning approach to implicitly learn the underlying Helmholtz free-energy from AIMD generated energies and pressures. The model, referred to as PIML-EOS, was trained and tested on warm dense polystyrene producing a fit within a 1% relative error for both energy and pressure and is shown to satisfy both the Maxwell and Gibbs–Duhem relations. In addition, we provide a path toward obtaining thermodynamic quantities, such as the total entropy and chemical potential (containing both ionic and electronic contributions), which are not available from current AIMD simulations.
Magnetic coupling in La2/3Sr1/3MnO3/SrRuO3 heterostructures grown on SrTiO3 (111) substrates with abrupt interface
Authors: Xu Yichi , Wang Qing , Jin Siqi , Liu Yuxiang , Qiu Xiaoyu , Tu Jie , Xu Xiang , Li Yingjia , Zheng Yonghui , Zhao Qingbiao , Zhong Ni , Xiang Pinghua , Wang Lingfei , Chen Binbin
Published: May 2024

We report on the magnetic coupling behavior in all-ferromagnetic La0.7Sr0.3MnO3/SrRuO3 (LSMO/SRO) heterostructures deposited on the SrTiO3 (111) substrate, where the interface leads to an enhanced exchange field as compared to the one deposited on SrTiO3 (001). Importantly, high-resolution scanning transmission electron microscopy reveals distinct interface structures of the (111) heterostructures depending on the growth sequence. The heterostructure with an SRO bottom layer shows an atomically flat and abrupt interface, while the one with an LSMO bottom layer shows a deformed interface due to the surface roughening of LSMO deposited directly on SrTiO3 (111). As a result, the heterostructure with an abrupt interface exhibits a robust antiferromagnetic coupling between LSMO and SRO, while the one with a rough interface shows negligible magnetic coupling. Our results demonstrate the key role of an abrupt interface in determining the magnetic properties of oxide heterostructures.
Discharge characteristics and development process of potential transfer gap in live-line work
Authors: Ding Tongshu , Xie Cheng , Liu Kai , Peng Yong , Li Guanlin , Jiang Tingxiu , Wu Shaocheng , Gao Jiachen
Published: May 2024

Potential transfer is an essential link in equipotential live-line work (EPLW), which has a potential safety hazard. To ensure the safety of the linemen, this paper conducted experimental research on this process. First, to investigate the discharge characteristics of the potential transfer gap in EPLW, this paper developed a simplified experimental platform to examine the relationship between the transfer voltage and gap distance, as well as the electrode structure, during the potential transfer process. Second, to explore the discharge development process of potential transfer, this paper built a discharge observation experimental platform to observe the discharge process and explore the effects of gap distance and type of the floating electrode on the discharge development process and potential transfer current. The research results are valuable for practical projects and linemen safety.
Development of fixed-point two-degree-of-freedom angular error measurement system with precision improvement function
Authors: Su Yu Ming , Liu Chien-Sheng
Published: May 2024

In the field of precision industries, measuring micro-angular errors plays a crucial role in improving the accuracy of equipment. Therefore, this study aims to develop a two-degree-of-freedom (two-DOF) angular error measurement system for simultaneously measuring the assembly angle errors of the bond head in a die bonding machine. This system is based on the laser collimation method and constructed by using components such as a fiber laser and position-sensitive detectors. It utilizes the angular drift compensation of the laser beam and averaging function to improve the measurement accuracy. In addition, the mathematical model of the proposed system was established by using skew-ray tracing. Through experiments, the measuring accuracy of ±0.25 arcsec and measuring repeatability of 0.3 arcsec could be achieved.
A model of heterogeneous undercooled liquid and glass accounting for temperature-dependent nonexponentiality and enthalpy fluctuation
Authors: Takeda Wataru , Lucas Pierre
Published: May 2024

Dynamic heterogeneity is a fundamental characteristic of glasses and undercooled liquids. The heterogeneous nature causes some of the key features of systems’ dynamics such as the temperature dependence of nonexponentiality and spatial enthalpy fluctuations. Commonly used phenomenological models such as Tool–Narayanaswamy–Moynihan (TNM) and Kovacs–Aklonis–Hutchinson–Ramos fail to fully capture this phenomenon. Here we propose a model that can predict the temperature-dependent nonexponential behavior observed in glass-forming liquids and glasses by fitting standard differential scanning calorimetry curves. This model extends the TNM framework of structural relaxation by introducing a distribution of equilibrium fictive temperature (Tfe) that accounts for heterogeneity in the undercooled liquid. This distribution is then frozen at the glass transition to account for the heterogeneous nature of the glass dynamics. The nonexponentiality parameter βKWW is obtained as a function of temperature by fitting the Kohlrauch-Williams-Watts (KWW) equation to the calculated relaxation function for various organic and inorganic undercooled liquids and glasses. The calculated temperature dependent βKWW shows good agreement with the experimental ones. We successfully model the relaxation dynamics far from equilibrium for two silicate systems that the TNM model fails to describe, confirming that temperature dependent nonexponentiality is necessary to fully describe these dynamics. The model also simulates the fluctuation of fictive temperature δTf during isothermal annealing with good qualitative agreement with the evolution of enthalpy fluctuation reported in the literature. We find that the evolution of enthalpy fluctuation during isothermal annealing heavily depends on the cooling rate, a dependence that was not previously emphasized.
Advanced K3V2(PO4)2O2F cathode for rechargeable potassium-ion batteries with high energy density
Authors: Gu Zhen-Yi , Wang Xiao-Tong , Zhao Xin-Xin , Cao Jun-Ming , Heng Yong-Li , Zheng Shuo-Hang , Liu Yan , Guo Jin-Zhi , Wang Si-Ze , Wu Xing-Long
Published: May 2024

Potassium-ion batteries (PIBs) have emerged as promising candidates for cost-effective and sustainable energy-storage systems. Nevertheless, limited by the large K+ radius, PIBs have great difficulty in figuring out and designing suitable host materials. Herein, a suitable cathode material K3V2(PO4)2O2F (KVPOF) for PIBs has been carefully prepared. It exhibits a high specific capacity close to the theoretical value, 116.3 mAh/g at 20 mA/g within the voltage window of 2.0–4.5 V vs K+/K, corresponding to a de-/intercalation process of ∼2 mol K+ per formula unit. In addition, it presents an average operating voltage plateau of about 3.5 V, resulting in an energy density of about 410 Wh/kg. The crystal structure and phase transition are revealed by in situ x-ray diffraction, and the structure is found to be fully reversible during the de-/intercalation of K+. Furthermore, the potential of KVPOF cathode for applications at low temperatures was explored, and the full cell matched with graphite anode demonstrated fair electrochemical performance. The experimental results suggest the feasibility of using KVPOF as cathode material for rechargeable PIBs.
Structural evolution and rheology of continuous shear-induced dense granular flow in unsteady state
Authors: Bai Jian , Zhang Guanghao , Hong Guangyang , Yu Aibing , Li Jian
Published: May 2024

The structural properties of particulate matter can significantly affect the rheology of the system. We report the structural evolution and flow properties of dense granular flows induced by Couette shear and try to reveal the relationship between them. In unidirectional shear, monodisperse particles undergo a transformation from disorder to order. Throughout this continuous process, both the velocity and shear strain rate of the particles experience alterations. By filling with particles of varying polydispersity, the structural potential of the system can be controlled, thereby influencing the extent of structural transformations. The results indicate that the transition in flow characteristics is suppressed as the initial filling in the system approaches from high to low structural potential. The results based on the local volume fraction and relative positions of particles suggest that it is due to the weakening of the structural thinning effect caused by order. We found that both fixed shear paths and more rotatable local structures caused a significant reduction in the contact force to transfer energy. Inertia number and apparent viscosity vary with volume fraction, indicating a transition in dense granular flow after volume fraction φ≳ 0.62, with the onset of significant structural thinning effects. We have revealed the physical mechanisms influencing fluidity from a local structural perspective and established the relationship between fluidity g and φ in the continuous process of unsteady flow.
Experimental investigation of storm sewer geyser using a large-scale setup
Authors: Mahyawansi Pratik , Zanje Sumit R. , Sharifi Abbas , McDaniel Dwayne , Leon Arturo S.
Published: May 2024

The storm sewer geyser is a process where an air–water mixture violently erupts from a manhole. Despite the low hydrostatic pressure, violent eruptions can achieve a height of tens of meters above the ground. This current study experimentally investigates large-scale violent geysers using a large air pocket inserted from a pressurized air tank. The total length of the pipe system is approximately 88 m with a 0.1572 m diameter pipe. This large-scale experiment facilitates the investigation of spontaneous geyser eruptions. This study identifies the role of air–water volume ratio and coefficient of pressure (ratio of absolute initial static pressure to initial dynamic pressure) on the geyser intensity using eruption images and pressure plots. A total of 116 cases are tested, in which the volume ratio is parametrically increased from 0 to 1.1 under various operating conditions. A geyser score is defined to quantify the geyser eruption nature based on visual observations. The key findings are as follows: first, a sharp transition in geyser intensity is observed at the critical volume ratio of 0.5, and pre-transition and post-transition intensity exhibit a linear relationship with the volume ratio; and second, the critical volume ratio linearly varies with the coefficient of pressure.
Vortex-dipole impingement with convex and concave boundaries
Authors: Kandre Shivakumar , Mudkavi Vidyadhar Y. , Patil Dhiraj V.
Published: May 2024

The vortex-dipole interactions with convex and concave boundaries in a two-dimensional domain are analyzed using the Bhatnagar–Gross–Krook (BGK) collision-based lattice Boltzmann method (LBM). The formation and detachment of the boundary layers at the flat wall creates new dipoles of non-identical vortices, following cyclic trajectories and exhibiting logarithmic variations in the production of maximum vorticity with Reynolds number (Re). The vortex-dipole interactions with concave boundaries produce a series of secondary dipoles, whose relative strength linearly decreases for the given Re in subsequent vortex-releasing events. Oblique interactions with cavity corners cause secondary dipoles to undergo head-on collisions at the domain center, influencing partner exchange and orthogonal propagation. Conversely, convex boundaries split the primary vortex-dipole upon impingement, intensifying the vorticity production and strain effects. Whereas, the larger ingestion of vorticity at the convex corners of the “T-shaped” cavity forms new dipoles, which deflect, rebound, and follow a parabolic trajectory for the vortex exchange. Normalized enstrophy, Ω(t), and palinstrophy, P(t), show distinct peaks during dipole interactions with boundary walls, influencing enhanced kinetic energy, E(t), decay. Moreover, the evolution of E(t) and Ω(t) satisfies the relation valid for no-slip boundaries. The collision behavior, vorticity production, and vortex rebound are functions of Re. The convex boundaries modify the scaling results of maximum Ω(t) and P(t) to higher exponent values than the dipole interactions with flat and concave boundaries.
High-quality flatband resonances in few-cell moiré superlattices by band-offset tuning
Authors: Hong Peilong , Yi Mingfang , Zhang Liwei , Liang Yi
Published: May 2024

Wave localization by flatband mechanisms underlies prominent moiré physics and relevant applications. While typically studied in periodic superlattices, the wave-confining capability of finite-size superlattices is important both fundamentally and practically. Here, we investigate wave localization in few-cell moiré superlattices through fine tuning of band offset, which is accomplished by jointly adjusting structural parameters of constitutive lattice. Remarkably, the quality factor Q, which reflects the capability of few-cell superlattices to localize wave, can reach quite high levels with appropriate band offset. Thus, superior wave localization is feasible in few-cell superlattices, indicated by the very high Q up to 104−105 for single-cell superlattices and extremely high Q up to >107 for double-cell superlattices. Moreover, the Q patterns are distinct for different flatband resonances and different number of cells, while narrow high-Q (∼108) branches appear for the triple-cell superlattices. The narrow high-Q branches are hard to be reached in practice, since it requires stringent control on structural parameters. In this respect, the double-cell superlattices are promising for exploiting unconventional effects induced by wave localization, since it can achieve extremely high-Q (>107) resonances within a sufficiently large tuning range. These results demonstrate the profound role of band-offset tuning in achieving strong wave localization in few-cell superlattices, which is useful for on-chip applications such as lasing, optical filters, and optical harmonic generation.
A multiscale symbolic approach to decoding delta and ripple oscillation bands as biomarkers for epileptiform discharges
Authors: Granado Mauro , Collavini Santiago , Martinez Nataniel , Miceli Federico , Rosso Osvaldo A. , Montani Fernando
Published: May 2024

We use a multiscale symbolic approach to study the complex dynamics of temporal lobe refractory epilepsy employing high-resolution intracranial electroencephalogram (iEEG). We consider the basal and preictal phases and meticulously analyze the dynamics across frequency bands, focusing on high-frequency oscillations up to 240 Hz. Our results reveal significant periodicities and critical time scales within neural dynamics across frequency bands. By bandpass filtering neural signals into delta, theta, alpha, beta, gamma, and ripple high-frequency bands (HFO), each associated with specific neural processes, we examine the distinct nonlinear dynamics. Our method introduces a reliable approach to pinpoint intrinsic time lag scales τ within frequency bands of the basal and preictal signals, which are crucial for the study of refractory epilepsy. Using metrics such as permutation entropy (H), Fisher information (F), and complexity (C), we explore nonlinear patterns within iEEG signals. We reveal the intrinsic τmax that maximize complexity within each frequency band, unveiling the nonlinear subtle patterns of the temporal structures within the basal and preictal signal. Examining the H×F and C×F values allows us to identify differences in the delta band and a band between 200 and 220 Hz (HFO 6) when comparing basal and preictal signals. Differences in Fisher information in the delta and HFO 6 bands before seizures highlight their role in capturing important system dynamics. This offers new perspectives on the intricate relationship between delta oscillations and HFO waves in patients with focal epilepsy, highlighting the importance of these patterns and their potential as biomarkers.
Enhanced performance of Ku-band GaN MMIC PA through embedded microfluidic cooling
Authors: Hong Wen , Zhang Li , Zhang Chao , Zhang Fang , Yue Shao-Zhong , Du Peng-Bo , Zheng Xue-Feng , Ma Xiao-Hua , Hao Yue
Published: May 2024

The impact of embedded microfluidic cooling on the performance of Ku-band gallium nitride (GaN) microwave monolithic integrated circuit (MMIC) power amplifiers (PAs) has been studied in this work. The research demonstrates that embedded cooling can substantially lower junction temperatures, mitigate the self-heating effect, and thereby improve the electrical performance of GaN MMIC PAs. Using merely 10.4 mW of pumping power (Ppump), the technology reduces the maximum junction temperature (Tj,max) from 216.7 to 147.8 °C. Furthermore, the system enhances the saturation current by 13.8%, increases output power (Pout) and gain (Gain) by 1.8 dB, elevates the power added efficiency (PAE) by 5.9%, and improves the heat flux of last gate (Qgate) to 37.3 kW/mm2 and the heat flux of MMIC (QMMIC) over 2.6 W/mm2, while reducing the thermal resistance (Rj-c) from 2.13 to 1.26 °C/W. Additionally, there is a notable improvement of the small signal gain (S21) by 2.5 dB. Therefore, the achievements in this work indicate that embedded cooling offers a powerful technique to suppress the thermal effects on GaN MMIC PAs, consequently improving their electrical performance.
Condensation shock induced in wet thermoacoustic prime mover
Authors: Hsu Shu-Han , Lin Hao-En
Published: May 2024

This Letter unveils a novel observation of condensation shock in a thermoacoustic prime mover with a wet stack, powered by a consistent 70 W heat input and maintained at atmospheric pressure. Intermittent pressure bursts, triggered by distinct acoustic cycles, reveal new characteristics of non-combustion-driven thermoacoustic instabilities, expanding the horizon beyond the energy conversion applications of traditional heat engines. Our findings, highlighted by pressure bursts reaching up to 35.8 kPa and detailed through time–frequency analysis, not only emphasize the critical role of phase-change dynamics but also pave the way for potential applications in heat transfer and material separation.
Non-trivial relationship between behavioral avalanches and internal neuronal dynamics in a recurrent neural network
Authors: Rabus Anja , Masoliver Maria , Gruber Aaron J. , Nicola Wilten , Davidsen Jörn
Published: May 2024

Neuronal activity gives rise to behavior, and behavior influences neuronal dynamics, in a closed-loop control system. Is it possible then, to find a relationship between the statistical properties of behavior and neuronal dynamics? Measurements of neuronal activity and behavior have suggested a direct relationship between scale-free neuronal and behavioral dynamics. Yet, these studies captured only local dynamics in brain sub-networks. Here, we investigate the relationship between internal dynamics and output statistics in a mathematical model system where we have access to the dynamics of all network units. We train a recurrent neural network (RNN), initialized in a high-dimensional chaotic state, to sustain behavioral states for durations following a power-law distribution as observed experimentally. Changes in network connectivity due to training affect the internal dynamics of neuronal firings, leading to neuronal avalanche size distributions approximating power-laws over some ranges. Yet, randomizing the changes in network connectivity can leave these power-law features largely unaltered. Specifically, whereas neuronal avalanche duration distributions show some variations between RNNs with trained and randomized decoders, neuronal avalanche size distributions are invariant, in the total population and in output-correlated sub-populations. This is true independent of whether the randomized decoders preserve power-law distributed behavioral dynamics. This demonstrates that a one-to-one correspondence between the considered statistical features of behavior and neuronal dynamics cannot be established and their relationship is non-trivial. Our findings also indicate that statistical properties of the intrinsic dynamics may be preserved, even as the internal state responsible for generating the desired output dynamics is perturbed.