bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying the Process Shift with Robust Control Charts in the Presence of Contamination
Authors: Wong Chiong Liong , Ng Kooi Huat , Tan Wei Lun
Published: August 2024

Conventional control charts have traditionally been reliable tools for monitoring processes under the assumption of normally distributed data. However, real-world data often deviate from this idealized normality, leading to reduced charting performance and potentially causing process anomalies to go unnoticed. In this study, by integrating robust statistical estimators and innovative charting techniques, robust control charts demonstrate their capability to effectively detect process shifts and abnormalities in a variety of challenging settings. Through Monte Carlo simulation studies and a real dataset application, this research provides insights into the benefits and limitations of robust control charts. Our findings indicate that the proposed robust control charts show a notable performance in detecting data anomalies, specifically for the shift in mean, outperforming conventional charts in this regard. Comparison among the three robust location estimators via simulations, namely Huber (H) and Biweight (B) estimators as well as the proposed Biweight estimator integrating theM-Scale(BM) estimator also demonstrate its superiority in handling shifting in mean process situations.
Some Properties of Hyperbolic k-Narayana Quaternions
Authors: Petpanwong Tanupat , Phudolsitthiphat Narawadee
Published: August 2024

In this paper, we introduced the hyperbolic k-Narayana quaternions. Several properties of these quaternions are investigated, including the Binet formulas, generating functions, and summation formulas. Moreover, some identities such as Catalan, Cassini, and d’Ocagne are obtained. Our results extend and generalize well-known theorems.
Professionelle Beziehungen im Kontext von Schulabsentismus
Authors: Ricking Heinrich , Bolz Tijs
Published: August 2024

Gründe von Schulabsentismus sind vielfältig – es können unterschiedliche Problem- und Risikokonstellationen dahinterstecken. Häufige Fehlzeiten bleiben kein schulisches Problem, denn Schülerinnen und Schüler mit Schulbesuchsproblemen begeben sich später oft in negative berufliche und soziale Entwicklungen. Im Rahmen von Präventionsmaßnahmen sind positiv erlebte Sozialbeziehungen und eine stimulierende Umgebung im schulischen Kontext elementar.
Online-Dating-Burnout: Entstehungsfaktoren und Interventionsmaßnahmen
Authors: Aretz Wera , Ehrenberg Katja
Published: August 2024

Dating-Apps werben damit, Beziehungen zu erleichtern. Gleichzeitig werden zunehmend dysfunktionale Aspekte diskutiert, die erheblichen Leidensdruck bis hin zu „Dating-Burnout“ verursachen können. Wir fassen erste wissenschaftliche Erkenntnisse zum Burnout-Syndrom im Dating-Kontext zusammen und zeigen therapeutische Unterstützungsmöglichkeiten auf.
Beziehungswelten heute
Authors: Huber Helene
Published: August 2024

Definitionen, Fakten, Relevantes – die PiD-Essentials fassen die wichtigsten Informationen zum Thema des Heftes knapp und übersichtlich für Sie zusammen.
Die Notwendigkeit von Galenikunterricht in der studentischen Ausbildung: ein Erfahrungsbericht
Authors: Staubach Petra , Hinkel Julia , Dietzel Janina , Keller-Melchior Regine , Mann Caroline
Published: August 2024

Ziele Der Erfahrungsbericht zeigt die Bedeutung der Galenik in der medizinischen Ausbildung im Fachbereich Dermatologie. Ziel ist es, die Relevanz galenischer Kenntnisse für die optimale und individualisierte Therapie topischer Arzneimittel zu beleuchten. Wir geben einen Überblick über die Vermittlung dieser Kenntnisse an Medizinstudierende.

Methodik Seit 2010 findet an der Mainzer Hautklinik im Rahmen des
Unterrichtsblocks Dermatologie Galenikunterricht in Form eines Kleingruppenpraktikums (je
13–16 Studenten über jeweils 1,5 Stunden) statt. Der Kurs wurde über die Jahre mehrfach
modifiziert. Im Folgenden werden die dabei gewonnenen Erfahrungen geteilt. Behandelt werden
der Aufbau der Haut, die unterschiedlichen Hauttypen, Lehre der unterschiedlichen Grundlagen,
Basistherapie sowie Kennenlernen wichtiger Wirkstoffe und ihre Wirkungen auf der Haut anhand
von Anwendungsbeispielen bei bestimmten Hauterkrankungen. Praktische Übungen ermöglichen es
den Studierenden, verschiedene Grundlagen einzuordnen und die geeignete Galenik anhand von
Patientenfällen zu ermitteln.

Ergebnisse Galenische Kenntnisse sind entscheidend für die Anwendung von Topika und ermöglichen patientenindividualisierte Therapien. Die Wichtigkeit der Galenik für alle medizinischen Fachrichtungen wird verdeutlicht. Geeignete Lehrmethoden wurden entwickelt, um das Interesse der Studierenden nicht nur in der Dermatologie zu wecken.

Schlussfolgerung Der Galenikunterricht ist ein wesentlicher Bestandteil der medizinischen Ausbildung. Er vermittelt wichtige Kenntnisse und Fertigkeiten, die für alle medizinischen Fachrichtungen relevant sind. Die Herausforderung besteht darin, die Relevanz der Galenik für alle Medizinstudierenden zu verdeutlichen und geeignete Lehrmethoden zu entwickeln, um das Interesse der Studierenden zu wecken. Das positive Feedback der Studierenden bestätigt die Wichtigkeit und Effektivität des Galenikunterrichts.
Value of Cerebroplacental Ratio in Predicting Adverse Perinatal Outcome in Term Pregnancies Complicated by Obesity
Authors: Eisenkolb Gabriel , Karge Anne , Ortiz Javier U. , Ostermayer Eva , Lobmaier Silvia M. , Kuschel Bettina , Graupner Oliver
Published: August 2024

To evaluate the performance of cerebroplacental ratio (CPR) in predicting composite adverse perinatal outcome (CAPO) in women with obesity compared to non-obese women at term.

This is a retrospective cohort study in a single tertiary referral centre over a 3-year period. All singleton pregnancies with CPR measurements ≥ 37 + 0 weeks and estimated fetal weight ≥ 10th centile and attempted vaginal delivery were included and divided into two groups defined by pre-pregnancy body mass index (BMI) </≥ 30 kg/m2. The presence of at least one of the following outcome parameters was defined as CAPO: operative delivery (OD) due to intrapartum fetal compromise (IFC), admission to the neonatal intensive care unit, umbilical cord arterial pH ≤ 7.15, 5 min Apgar < 7. The prognostic performance of CPR MoM was evaluated using receiver operating characteristic (ROC) analysis.

The study cohort included 1207 pregnancies, of which 112 were women with a BMI ≥ 30 kg/m2. In obese women, CAPO occurred in 21 cases (18.8%) compared to 247 (22.6%) cases in women with BMI < 30 kg/m2 (p = 0.404). In the entire study cohort, CPR MoM was significantly lower in the CAPO and OD for IFC group. ROC analyses revealed a significant predictive value of low CPR MoM for CAPO in obese women (AUC = 0.64, p = 0.024). Furthermore, CPR was predictive for OD for IFC not only in obese (AUC = 0.72, p = 0.023) but also in non-obese (AUC = 0.61, p = 0.003) women.

Low CPR MoM was predictive for CAPO and OD for IFC in obese women without additional risk factors. However, the overall predictive performance of CPR for CAPO in obese women was poor.
The generation of acoustic multi-vortex beams using a phase-only holographic lens
Authors: Zhang Rujun , Cai Feiyan , Mo Yiying , Luo Qingying , You Chengxuan , Zheng Hairong
Published: August 2024

The generation of acoustic vortex beams has garnered significant research interest in recent years due to their diverse applications, including acoustic communication, particle manipulation, and biomedical ultrasound. However, incorporating more vortices and expanding the capacity of these beams and related devices in three dimensions remain challenging. In this study, we propose a phase-constrained iterative angular spectrum method for fabricating a 3D-printed holographic lens capable of reconstructing multi-vortex acoustic beams within a 3D volume. To evaluate the performance of the proposed lens, we conduct tests using both numerical simulations and practical underwater measurements. Furthermore, we demonstrate the transfer of acoustic angular momentum to two absorbent acoustic objects, achieving rotation of these objects with the performance influenced by vortices at target positions. The results indicate that the proposed method can generate multiple acoustic vortex beams within a 3D volume. This capability enhances the effectiveness and versatility of various applications, such as the manipulation of three-dimensional objects and high-density information transmission.
Numerical analysis of the impact of helical-blade design on flow characteristics and energy utilization in vertical-axis water turbine
Authors: Kong Fankai , Wang Song , Liu Hengxu , Liu Changkun , Xiong Fengao , Ding Huaqiu
Published: August 2024

In this study, a vertical-axis helical-blade water turbine is innovatively proposed by drawing on the design scheme of the traditional straight-blade turbine, compared to which this blade form can effectively improve the self-starting capability and energy capture efficiency of the turbine. The study analyzes the hydrodynamic performance of the device under different parameters using CFD (computational fluid dynamics) software STAR-CCM+ and overlapping mesh technique, and the CFD simulation results are verified with published experimental work. First, the design concept of the hydraulic turbine is presented, focusing on the design of the blades and transmission mechanism to ensure the stability of the structure. Second, the effect of two-dimensional parameters on the flow field characteristics and efficiency is investigated, and then three-dimensional design parameters, such as blade helix angle and hub-to-tip ratio, are considered. The results show that a 20% increase in blade density results in a 10.74% increase in efficiency. Regarding flow velocity, a maximum output of 2.4 kW was achieved for four operating conditions (1.0, 1.5, 2.0, and 2.5 m/s). In addition, the average dynamic torque of the helical-blade turbine was 16.44% higher than that of the straight-blade turbine, indicating superior self-starting capability. It was also found that at an aspect ratio of 1.5–1.75 and a helix angle of 80°, the energy capture efficiency of the helical-blade turbine was 33.7%, which was 45.3% higher than that of the straight-blade turbine. Comparative analysis shows that the vertical-axis helical-blade turbine has favorable hydrodynamic performance, especially under low flow conditions, and the design scheme shows obvious advantages, which makes up for the defects of the traditional vertical-axis straight-blade turbine with poor self-starting ability and low efficiency, and fills up the research gaps of vertical-axis turbine design optimization, which is of certain research value.
Structures and chemical bonding of B6O50/−/2−: The first boron oxide clusters with five-membered ring and their structural diversity
Authors: Tian Wen-Juan , Guo Zi-Yan , Yan Miao
Published: August 2024

Based upon global-minimum searches and first-principles electronic structural calculations, we present the perfectly planar B6O50/−/2− (1–3) systems. Notably, the C2v B6O50/− (1–2) clusters mark a groundbreaking advancement as the first boron oxide clusters to feature a five-membered ring. Both structures exhibit remarkable similarity, each characterized by a central B3O2 ring surrounded by three terminal BO groups. However, a notable difference lies in the bond lengths within the B3O2 core, which are uniform in the former but uneven in the latter. Detailed canonical molecular orbital and AdNDP analyses reveal the delocalized π bonds over the B3O2 ring, affirming the π aromaticity of B6O5−. The Cs B6O52− (3) cluster showcases a chain-like arrangement with three terminal BO groups and a typical OBO group linked to a B2 core, emphasizing the crucial role of electrons in shaping the structure. Detailed chemical bonding analyses reveal the presence of dual three-center four-electron (3c–4e) π hyperbonds in 3, shedding further light on its unique bonding characteristics. Moreover, this study comprehensively extends the B(BO)n0/− (n = 1–5) series and provides valuable perspectives on their structural evolution.
Enhanced energy transfer via surface plasmons in ternary liquid systems of coumarin-151, ethanol, and benzaldehyde
Authors: Verma Richa , Rajput Pratima
Published: August 2024

This investigation explores the plasmonic effect on molecular fluorescence within ternary liquid systems comprising 7-amino-4-(trifluoromethyl) coumarin (C-151) laser dye, ethanol, and benzaldehyde. A key aspect of our investigation involves examining ZrN nanosphere and ZrN nanoshell within these mixtures, marking the first instance of such an analysis in ZrN and ternary liquid compositions. Utilizing experimentally obtained refractive indices, we evaluate resonance peaks in the spectra and their shifts. Our findings reveal improved fluorescence characteristics in C-151 laser dye with the addition of ZrN nanoparticles. Theoretical results suggest that plasmonic nanoparticles play a significant role in enhancing dye fluorescence. These findings deepen our understanding of plasmonics in complex liquid environments and highlight ZrN's potential as an effective alternative plasmonic material for efficient molecular energy transfer at the nanoscale.
Exploring aerodynamics of a rectangular cylinder using flow field and surface pressure synchronized testing technique
Authors: Liu Junle , Tse K. T. , Hu Gang , Liu Chang , Zhang Bingchao , Kwok Kenny C. S.
Published: August 2024

This study uses two wind tunnel testing approaches: a sole high-frequency pressure scanning (HPS) approach, and a synchronized particle image velocimetry (PIV) and multipoint pressure scanning (SPMPS) approach, to investigate aerodynamic characteristics of a rectangular cylinder. HPS and SPMPS share identical experimental settings and device arrangements, while the SPMPS sampling frequency is much lower than HPS because the PIV system has a low sampling frequency in this study. SPMPS can simultaneously capture the flow field and surface pressure information. PIV measurement provides instantaneous flow field information, helping to analyze flow characteristics, and surface pressure taps offer both high- and low-frequency surface pressure information. It was found that for the rectangular cylinder, the zones of high turbulent kinetic energy and turbulent shear stress are associated with the lower negative pressure coefficient. In addition, diverse coherent structures in the instantaneous flow field resemble different critical points such as the saddle point, the repelling focus, and the attracting focus, and these coherent structures are associated with drastic changes in the pressure distribution or extreme pressure values. In particular, there is a visible flow reattachment, and the lift coefficient is more sensitive to the pressure distribution around the trailing edge of the rectangular cylinder. The convective velocity of wall pressure fluctuations is calculated based on the spatial temporal correlation of HPS information, and the convective velocity on the upper surface of the cylinder of SR = 3.25 is around 3.1 m/s providing evidence that Taylor's hypothesis breaks down for wall pressure fluctuations.
Neural network-based regression for effective parametric study of micro-pin fin heat sinks
Authors: Choi Geunhyeok , Kim Seong Jin , Shin Seungwon
Published: August 2024

Micro-pin fin heat sinks are widely used to cool miniature devices. The flow characteristics and cooling performance of these heat sinks are highly dependent on their geometric configuration. Previous studies have focused on optimizing the design so that the pressure drop decreases, while the heat transfer performance is maintained. However, limited numbers of geometries have been explored, mainly considering only homogeneous pin fin arrays. In this study, we propose a neural network-based regression approach called the flow-learned building block (FLBB) and develop an effective parametric study and optimization for micro-pin fin heat sinks including heterogeneous geometries. The prediction capabilities of the FLBB are verified by comparing the predicted results with direct numerical simulation results for various pitch distances, pin sizes, and arrangements at Reynolds numbers from 1 to 100. Furthermore, we demonstrate the applicability of the FLBB to different working fluids, quantified by the Prandtl number (0.71 ≤ Pr ≤ 5.86). Leveraging the reliable and effective prediction capabilities of our neural network-based approach, we perform parametric studies of micro-pin fin heat sinks for working fluids of air and water with the aim of minimizing the pump power and achieving uniform heat transfer along the pin fins.
Three-dimensional vortex and gas entrainment analysis in rotating liquid flow with a free surface
Authors: Amar S. D. , Portnikov D. , Rashkovan A. , Ziskind G.
Published: August 2024

In nature and engineering, fluid movements involving swirling patterns, or vortices, are common occurrences. Some flows involve free-surface vortices that can potentially lead to a phenomenon termed gas entrainment (GE). There is no validated tool that can predict the free-surface profile of the gas core prior and subsequent to the GE. This study focuses on experimental and numerical investigation of flows with unsteady free-surface vortices that can potentially lead to gas entrainment. An extensive experimental work, performed in a dedicated experimental setup built in the present study, yields two main contributions. First, a new GE onset criterion, based on implementing dimensional analysis to the experimental results, is developed. The onset criterion is found to be suitable also for other experiments in the literature. Second, the experimental acquisition of the free-surface profiles, obtained with a high-speed camera, is used for validating the numerical approach. This three-dimensional numerical tool incorporates Large Eddy Simulation to capture turbulence, with Volume-of-Fluid approach to simulate free-surface profiles. The model predicts with high accuracy the free-surface profiles in cases with and without GE, observed experimentally. Then, the detailed simulation results for this type of flows are analyzed quantitatively for the first time in the available literature, using radial, axial, and tangential velocity components. The present study sheds new light on free-surface vortex flows, in general. The experimental and numerical achievements in this study can serve as a tool both to predict the free-surface flow profiles with high accuracy and to prevent gas entrainment in the engineering systems.
Turbulent flow structures and Reynolds stress anisotropy in an asymmetric sinuous mobile channel
Authors: Gurugubelli Yatirajulu , Timbadiya P. V. , Barman Bandita
Published: August 2024

In the current experimental study, turbulent flow structures and Reynolds stress anisotropy in an asymmetric sinuous mobile channel are investigated. Experiments were conducted in a laboratory on an asymmetric plane-shaped sinuous model of a riverway with a sinuosity of 1.23. Three-dimensional instantaneous velocity data were measured using an acoustic Doppler vectrino profiler and processed to compute turbulent flow structures and Reynolds stress anisotropy. Spectral analysis of the streamwise fluctuating component of velocity shows the presence of “−1” and “−5/3” slope regions. Analysis of bursting events in the near-bed region reveals that the contribution of sweep and ejection events is more dominant than outward and inward interactions. The intermixing of events with depth shows the presence of helical flow. The probability of occurrence of bursting events indicated that the ejections are higher than other events. The Reynolds stress anisotropy tensor showed higher contribution in the streamwise followed by transverse and vertical directions, respectively, at all locations. The anisotropic invariant map indicated two-component turbulence in the near-bed region and one-component turbulence toward the surface at upstream and apex locations. At the bend downstream, the two-component turbulence diminished near the bed, and one-component turbulence increased with vertical depth. The eigenvalues of the non-dimensional anisotropy tensor indicated that the principal component was higher than the other two components in the near-bed region and started decreasing with increasing depth. The anisotropic invariant function showed that the near-bed region tended to approach an isotropic limit but departed from it in the outer flow region with increasing vertical depth.
Development of fast 2.5 MeV neutron detectors for high-intensity stray magnetic field environments
Authors: Molin A. Dal , Guiotto F. , Putignano O. , Rosa M. Dalla , Franz P. , Grosso G. , Monguzzi A. , Cippo E. Perelli , Pollice L. , Rigamonti D. , Tedoldi L. G. , Zuin M. , Tardocchi M.
Published: August 2024

Several small to medium-scale magnetic confinement fusion devices operate using deuterium as fuel. These low neutron rate (108–1010 n/s) devices rely on 2.45 MeV neutron measurements to validate physical models and to assess their performance. Given the modest rate, neutron monitors have to be placed as close as possible to the machine to maximize data gathering. In these regions, intense stray magnetic fields could affect the detector’s performance. In this work, the development of a neutron detector based on an EJ-276D scintillator crystal coupled with a SiPM and a custom-made readout system is presented. The detector has particle discrimination capability and is insensitive to magnetic fields.
Room-temperature spin pumping from canted antiferromagnet α-Fe2O3
Authors: Gabrielyan D. , Volkov D. , Kozlova E. , Safin A. , Kalyabin D. , Nikitov S.
Published: August 2024

Spin pumping from canted antiferromagnets is a cutting-edge topic in modern spintronics. The interest for fundamental and applied research that these materials arouse is related to their unusual structure, namely, with a small canting of the magnetic sublattices, which is explained by the presence of the Dzyaloshinskii–Moriya interaction. Through this effect, it becomes possible to experimentally study quasi-ferromagnetic resonance spectra and spin pumping in the range of tens of GHz at room temperature. In this paper, an experimental and theoretical investigation of spin pumping from an antiferromagnet with weak ferromagnetism, α-Fe2O3, is carried out. The conversion of the precession of the magnetization vector, excited by an alternating magnetic microwave field, into a constant voltage is realized using the inverse spin Hall effect in the hematite/heavy metal structure. Using a constant magnetic field up to 5 kOe, the resonant frequency of such a detector is tunable over a wide range up to 32 GHz with potential sensitivity reaching 10.1 μV/W. Confirmation of the measurement of the spin current is the change in the sign of Vsp when the polarity of the constant magnetic field alters. We believe that these studies will make a major contribution to the understanding of the physics of the spin-pumping effect from antiferromagnets and will also help in the development of devices for quantum technologies and next-generation communication technologies.
Versatile multi-energy hard x-ray camera to study confined and unconfined fast electron dynamics and anisotropies (Invited)
Authors: Barbui T. , Delgado-Aparicio L. F. , Savoye-Peysson Y. , Stratton B. , Dumont R. , Hill K. W. , Pablant N. A. , Wallace J. , Wisniewski J. ,   WEST team
Published: August 2024

A powerful and flexible hard x-ray (HXR) camera has been recently installed and tested on the WEST tokamak (CEA, France) in collaboration with the Princeton Plasma Physics Laboratory. The diagnostic is a pinhole camera fielded with a 2D pixel detector equipped with a 1 mm thick CdTe sensor. The novelty of this diagnostic technique is the detector’s capability of adjusting the threshold energy at the pixel level. This innovation provides great flexibility in the energy configuration, allowing simultaneous space, energy, and time resolved x-ray measurements. The novel camera has been used to measure the core radiation from non-Maxwellian (fast) electrons accelerated by Lower Hybrid (LH) waves and also the beam–target emission of tungsten in the divertor region produced by fast electron losses interacting with the target. In addition, anisotropic hard x-ray emission has been detected for the first time at the WEST core and edge plasma, with opposite toroidal intensity trends. Experimental vertical and toroidal HXR profiles have been successfully reproduced with the LH code LUKE.
Collection optics of JT-60SA edge Thomson scattering diagnostic
Authors: D’Isa F. A. , Fassina A. , Giudicotti L. , Soare S. , Tojo H. , Ohtani Y. , Akimitsu M. , Crescenzio G. , Girardini M. , Slemer A. , Grossi A. , Mazzarolo E. , Pasqualotto R.
Published: August 2024

The mission of the JT-60SA project is to complement ITER’s capabilities by addressing the fundamental physics and engineering challenges necessary to develop a practical and reliable fusion power plant. Diagnostics play a pivotal role in achieving this mission, especially the Thomson Scattering (TS) diagnostic systems developed by a collaborative Japan–EU team. The edge Thomson scattering of JT-60SA is tailored to measure the low field side outer region of the plasma, in particular, to resolve the electron temperature Te and density ne. The collection optics of the edge TS system have a critical role in meeting the required field of view and spatial resolution despite the limited space. This work presents a comprehensive optomechanical design of the optics assembly, whose main features are telecentricity and compactness, highlighting its capabilities. The tests undertaken to verify its performance: focal plane identification, thermal cycle, and magnification, are described.
Characterization of plasma parameters and neutral particles in microwave and radio frequency discharges in the Toroidal Magnetized System
Authors: López-Rodríguez D. , Crombé K. , Goriaev A. , Buermans J. , Adriaens A. , Kovtun Yu. , Dittrich L. , Petersson P. , Wauters T. , Brezinsek S.
Published: August 2024

A characterization of plasma parameters and neutral particle energies and fluxes has been performed for radio frequency and microwave discharges in the Toroidal Magnetized System (TOMAS). A movable triple Langmuir probe was used to study the electron densities and temperatures, and a time-of-flight neutral particle analyzer was used to measure the energy and fluxes of neutral particles, as a function of the total injected power and the antenna frequency used to generate the plasma. The experimental results can provide information on the behavior of neutral particles at low energies in wall conditioning plasmas.
Surrogate-based cross-correlation for particle image velocimetry
Authors: Lee Yong , Gu Fuqiang , Gong Zeyu , Pan Ding , Zeng Wenhui
Published: August 2024

This paper presents a novel surrogate-based cross-correlation (SBCC) framework to improve the correlation performance for practical particle image velocimetry (PIV). The basic idea is that an optimized surrogate filter/image, replacing one raw image, will produce a more accurate and robust correlation signal. Specifically, the surrogate image is encouraged to generate a perfect Gaussian-shaped correlation map to tracking particles (PIV image pair) while producing zero responses to image noise (context images). The problem is formulated with an objective function composed of surrogate loss and consistency loss. As a result, the closed-form solution provides a multivariate operator that could consider other negative context images. Compared with state-of-the-art baseline methods (background subtraction, robust phase correlation, etc.), our SBCC method exhibits significant performance improvement (accuracy and robustness) in the synthetic dataset and several challenging experimental PIV cases. Moreover, our implementation with all details (https://github.com/yongleex/SBCC) is also available for interested researchers.
Improved memory truncation scheme for quasi-adiabatic propagator path integral via influence functional renormalization
Authors: Liu Limin , Ren Jiajun , Fang Weihai
Published: August 2024

Accurately simulating non-Markovian quantum dynamics in system–bath coupled problems remains challenging. In this work, we present a novel memory truncation scheme for the iterative quasi-adiabatic propagator path integral (iQuAPI) method to improve accuracy. Conventional memory truncation in iQuAPI discards all influence functional beyond a certain time interval, which is not effective for problems with a long memory time. Our proposed scheme selectively retains the most significant parts of the influence functional using the density matrix renormalization group algorithm. We validate the effectiveness of our scheme through simulations of the spin-boson model across various parameter sets, demonstrating faster convergence and improved accuracy compared to the conventional scheme. Our findings suggest that the new memory truncation scheme significantly advances the capabilities of iQuAPI for problems with a long memory time.
Tutorial on the stochastic simulation of dissipative quantum oscillators
Authors: Hogg C. R. , Glatthard J. , Cerisola F. , Anders J.
Published: August 2024

Generic open quantum systems are notoriously difficult to simulate unless one looks at specific regimes. In contrast, classical dissipative systems can often be effectively described by stochastic processes, which are generally less computationally expensive. Here, we use the paradigmatic case of a dissipative quantum oscillator to give a pedagogic introduction to the modeling of open quantum systems using quasiclassical methods, i.e., classical stochastic methods that use a “quantum” noise spectrum to capture the influence of the environment on the system. Such quasiclassical methods have the potential to offer insights into the impact of the quantum nature of the environment on the dynamics of the system of interest while still being computationally tractable.
Complex impedance studies of the precipitation-hardened lithium sodium niobate ferroelectrics
Authors: Shao Jianing , Zheng Mupeng , Gao Xin , An Shuai , Zhu Mankang , Zhao Changhao , Hou Yudong
Published: August 2024

Precipitation hardening has been demonstrated as a good practice to suppress domain wall mobility and reduce losses in piezoceramics, especially when subjected to high-power drive. The hardening effect is generally determined by the morphology of precipitates introduced during the high-temperature aging treatment. In the present work, impedance spectroscopy is performed on the as-quenched and aged (Li, Na)NbO3 (LNN) solid solution to clarify the influence of aging treatment on the conductivity and electrical heterogeneity of LNN samples. The as-quenched LNN sample shows a lower resistivity due to higher oxygen vacancy concentration, which can be largely eliminated by reoxidation during the aging process. Moreover, the LiNbO3 (LN) precipitate-caused electrical heterogeneity is clarified by analyses of the impedance spectra fitted by an equivalent circuit and the activation energy calculated from relaxation peaks. The revealed impedance changes provide a foundation for future optimization strategies of precipitation-hardened piezoelectric ceramics.
Magnetic phase transition and valley splitting in Janus GdBrI bilayer
Authors: Lv Jiapeng , Huang Wenchuan , Li Shujing
Published: August 2024

The successful synthesis of two-dimensional Janus MoSSe and the emergence of anomalous valley Hall effect in magnetic transition metal dihalides has propelled valleytronics. In this study, we investigated the influence of stacking order on bilayer Janus GdBrI using first-principles computational methods. The calculation results indicate that the interlayer coupling is highly dependent on the stacking order, enabling transition between ferromagnetic (FM) and antiferromagnetic (AFM) via lateral displacement. Interestingly, the FM-coupled systems exhibit bipolar magnetic semiconductor characteristics. Under the influence of spin–orbit coupling, the system undergoes valley splitting, and the non-zero valley-contrast Berry curvature can be observed. Additionally, the interlayer magnetic coupling of the system can also be tuned to switch between AFM and FM states through biaxial strain and charge doping. These intriguing findings provide theoretical insights for the design of spintronic devices.
The growth-adjusted CiteScores of Physics of Fluids
Authors: Zatloukal M. , Giacomin A. J. , Phan-Thien N.
Published: August 2024

From Phan-Thien et al., “Growth-adjusted CiteScore,” Phys. Fluids 36(7), 070403 (2024), we learn that journal growth decreases CiteScore (all else being held equal). In this Editorial, we apply the teachings of Phan-Thien et al. to growth-adjust the CiteScore of the journal Physics of Fluids. We do so for the years for which the data are available, 2016–2023. We find that, over the course of its history, the growth of Physics of Fluids often suppressed its CiteScore.
The Lorenz ratio as a guide to scattering contributions to transport in strongly correlated metals
Authors: Sun Fei , Mishra Simli , Stockert Ulrike , Daou Ramzy , Kikugawa Naoki , Perry Robin S. , Hassinger Elena , Hartnoll Sean A. , Mackenzie Andrew P. , Sunko Veronika
Published: August 2024

In many physical situations in which many-body assemblies exist at temperature
T
, a characteristic quantum-mechanical time scale of approximately

ℏ
/
k

B

T

can be identified in both theory and experiment, leading to speculation that it may be the shortest meaningful time in such circumstances. This behavior can be investigated by probing the scattering rate of electrons in a broad class of materials often referred to as “strongly correlated metals”. It is clear that in some cases only electron–electron scattering can be its cause, while in others it arises from high-temperature scattering of electrons from quantized lattice vibrations, i.e., phonons. In metallic oxides, which are among the most studied materials, analysis of electrical transport does not satisfactorily identify the relevant scattering mechanism at “high” temperatures near room temperature. We therefore employ a contactless optical method to measure thermal diffusivity in two Ru-based layered perovskites, Sr
3
Ru
2
O
7
and Sr
2
RuO
4
, and use the measurements to extract the dimensionless Lorenz ratio. By comparing our results to the literature data on both conventional and unconventional metals, we show how the analysis of high-temperature thermal transport can both give important insight into dominant scattering mechanisms and be offered as a stringent test of theories attempting to explain anomalous scattering.
Reducing the uncertainty in estimating soil microbial-derived carbon storage
Authors: Hu Han , Qian Chao , Xue Ke , Jörgensen Rainer Georg , Keiluweit Marco , Liang Chao , Zhu Xuefeng , Chen Ji , Sun Yishen , Ni Haowei , Ding Jixian , Huang Weigen , Mao Jingdong , Tan Rong-Xi , Zhou Jizhong , Crowther Thomas W. , Zhou Zhi-Hua , Zhang Jiabao , Liang Yuting
Published: August 2024

Soil organic carbon (SOC) is the largest carbon pool in terrestrial ecosystems and plays a crucial role in mitigating climate change and enhancing soil productivity. Microbial-derived carbon (MDC) is the main component of the persistent SOC pool. However, current formulas used to estimate the proportional contribution of MDC are plagued by uncertainties due to limited sample sizes and the neglect of bacterial group composition effects. Here, we compiled the comprehensive global dataset and employed machine learning approaches to refine our quantitative understanding of MDC contributions to total carbon storage. Our efforts resulted in a reduction in the relative standard errors in prevailing estimations by an average of 71% and minimized the effect of global variations in bacterial group compositions on estimating MDC. Our estimation indicates that MDC contributes approximately 758 Pg, representing approximately 40% of the global soil carbon stock. Our study updated the formulas of MDC estimation with improving the accuracy and preserving simplicity and practicality. Given the unique biochemistry and functioning of the MDC pool, our study has direct implications for modeling efforts and predicting the land–atmosphere carbon balance under current and future climate scenarios.
The classical and quantum particle on a flag manifold
Authors: Bykov Dmitri , Kuzovchikov Andrew
Published: August 2024

In the present paper we consider two related problems, i.e. the description of geodesics and the calculation of the spectrum of the Laplace–Beltrami operator on a flag manifold. We show that there exists a family of invariant metrics such that both problems can be solved simply and explicitly. In order to determine the spectrum of the Laplace–Beltrami operator, we construct natural, finite-dimensional approximations (of spin chain type) to the Hilbert space of functions on a flag manifold.
Arm-locking frequency noise suppression for astrodynamical middle-frequency interferometric gravitational wave observatory
Authors: Nian Jun , Ni Wei-Tou
Published: August 2024

For space gravitational wave detection, arm locking is a proposal useful in decreasing the frequency noise of the laser sources for current developing space missions Laser Interferometer Space Antenna (LISA) and Taiji/TianQin. In this paper, we study the application of arm locking to the Astrodynamical Middle-frequency Interferometric Gravitational wave Observatory (AMIGO) to decrease the frequency noise of laser sources. For AMIGO, the arm-locking technique can suppress the laser frequency noise by three orders of magnitude. The advantage of this is to make the auxiliary noise assignment for AMIGO easier and more relaxed. For the first-generation time-delay interferometry (TDI) configuration, the laser frequency noise contribution is already below the core noise contribution. For the simple Michelson TDI configuration (X0), the arm locking makes the acceleration-thrust scheme, the delay-line scheme, or the combined scheme easier to implement. Within a relatively short period of less than a day (compared to less than twenty days for LISA/Taiji), the Doppler frequency pulling can be efficiently reduced to within ±0.001 Hz and does not affect the mission duty cycle much.
Simulation study on electrical tree propagation under electrical and mechanical stresses
Authors: Liang Hucheng , Du Boxue
Published: August 2024

Epoxy insulators in gas-insulated power apparatus are subjected to the combined effects of electrical and mechanical loads. In this work, a simulation model is built based on the energy theory to explore the electrical tree growth of epoxy resin under tensile and compressive stresses. With increasing AC voltage, the electrical tree growth is promoted, exhibiting a morphology with more branches. Tensile stress accelerates the electrical tree growth, while proper compressive stress has the opposite effect. However, when the compressive stress exceeds a certain value, electrical tree growth is promoted again. When the mechanical stress is vertical to the needle electrode, these effects primarily impact the length of the trees. Conversely, in parallel cases, mechanical stress mainly affects the width of the electrical trees. Filler doping play the role of obstacles as well as enhancing the electric field concentration, the electrical tree growth is firstly inhibited and then promoted as the doping content increases. The electrical tree morphologies of simulation and experiment are in good consistency, proving the reasonability of the simulation model.
Gear fault diagnosis using spectral Gini index and segmented energy spectrum
Authors: Tong Shuiguang , Fu Zilong , Tong Zheming , Cong Feiyun
Published: August 2024

Fault diagnosis of gears is crucial for maintaining the stable operation of a gearbox within a mechanical system. Traditional envelope demodulation methods depend on the distribution of sidebands around a central frequency. However, due to various interferences such as amplitude modulation, frequency modulation and assembly errors, the sidebands do not always distribute regularly. To circumvent dependence on sidebands distribution, a novel method, based on spectral Gini index (SGI) and segmented energy spectrum, is proposed to extract fault features from the perspective of energy variation in a specific frequency band to achieve fault diagnosis. Considering the operational characteristics of gears, the vibration signal is segmented into a series of short-time vectors according to the meshing frequency, to calculate the frequency response during each gear engagement. The SGI is employed as a new method to determine the optimal frequency band. An energy sequence is obtained by calculating the energy values of the segmented vectors within the optimal frequency band. Subsequently, the spectrum of the energy sequence is computed to identify the fault characteristic frequency. For comparison, methods based on band-pass filtering and envelope demodulation are also conducted and discussed. The effectiveness of the proposed method is validated through numerical and experimental studies.
Prediction of remaining life of bearings based on integral correction and global attention mechanism
Authors: Sun Xianbin , Kong Liya , Yin Gang , Zheng Xin
Published: August 2024

Rolling bearing failure is an important cause of equipment failure, and its remaining service life prediction is a key research direction to detect the health status and service life of machinery. However, the feature indicators extracted based on expert knowledge cannot better characterize the trend of bearing degradation in the early and middle term, and the neural network has poor prediction effect for longer sequences. To address the above problems, a method is proposed to predict the remaining life of rolling bearings based on integral transformation and global attention mechanism. Firstly, the time domain feature indicators of vibration signals are integrally corrected and transformed into integral corrected indicators to solve the problem of inconspicuous information of bearing degradation in the front and middle term; then, a long and short time memory neural network based on global attention mechanism is built to deeply explore the mapping relationship between the integral feature indicators of long sequences and the remaining life of bearings, which gives full play to the advantage of global attention on weight optimization allocation; finally, a linear regression function is used to construct health indicators and achieve the prediction of the remaining life of rolling bearings. Experiments were conducted on the bearing data of PRONOSTIA and compared with other methods, and the results showed that the method has better accuracy and prediction precision than other methods.
ZPW-2000A track circuit anomaly detection based on dual-channel decision fusion
Authors: Lin Junting , Niu Pengyuan , Li Qian , Wang Bohan
Published: August 2024

This paper proposes an anomaly detection method for the ZPW-2000 A track circuit that analyzes massive monitoring data to reflect the circuit’s operational status in real time. The study utilizes two independent parallel channels for anomaly detection: Extended Isolated Forest (EIF) and Variable Auto-Encoder (VAE), each employing a distinct detection mechanism. In order to enhance the training effect, the VAE model’s training dataset is initially refined through the EIF model for data purification. Anomaly detection outputs from the dual channels are mapped to a two-dimensional space, and using Kernel Density Estimation for effective decision fusion. The dual-channel decision fusion model exhibits exceptional performance, achieving a detection accuracy of 98.78%, a precision rate of 97.62%, a recall of 96.48%, and an F1 score of 97.05%, significantly surpassing the performance of the standalone EIF or VAE methods. This technique substantially enhances the accuracy and robustness of anomaly detection. It introduces a fresh perspective and approach to anomaly detection in track circuit.
A model fusion optimization strategy for lithium mill equipment state prediction
Authors: Xiao Yanjun , Ning Fuan , Yin Shanshan , Wan Feng
Published: August 2024

Improving the ability and accuracy of intelligent state prediction of large and complex equipment is one of the important directions of current intelligent operation and maintenance technology research. Due to the influence of insufficient analysis of equipment degradation characteristics, single function of traditional prediction model, and difficulty in determining the optimal parameters of the model make the prediction effect poor. In this paper, a state prediction model fusion optimization strategy is proposed for lithium mill equipment as an example. Based on the process flow and vibration mechanism, the inherent vibration characteristics of the roller bearing system are analyzed, and the degradation characteristics of the roller bearing under resonance conditions are explored from the finite element equivalent model, so as to determine the equipment operation stage and the starting point of degradation. The state prediction task is divided into degradation phase and residual life prediction phase, and Time-Convolutional Denoising Autoencoder (TCDAE) and two-layer Sparse Auto Encoder (SAE) are designed for data feature enhancement and degradation feature fusion and dimensionality reduction. Construct BO-BiGRU state prediction model to mine the feature information hidden in the whole time series of data points and adjust the model parameters adaptively using Bayesian Optimization method. The novelty of this study is to analyze the degradation characteristics of key components, correct the theoretical degradation starting point by using the degradation trend formula, and establish a unified framework from monitoring data to condition prediction. Compared with the original model constructed by the above algorithm, the fusion model proposed in this paper has significantly improved performance. The data analysis shows that the prediction accuracy after model fusion is substantially improved, and the accuracy after TCDAE feature enhancement is improved by about 10.2%, the accuracy after two-layer SAE model fusion and dimensionality reduction improved by about 9.8%, and the state accuracy after BO-BiGRU model improved by about 11.6%. The crux to the research depends on the construction of a state prediction model, which is based on the analysis of the bearing degradation process and the effective integration of algorithms. Predictive maintenance of critical components also improves product quality.
Frequency selective illumination for high aperture coherence scanning interferometry
Authors: Künne Marco , Stelter Andre , Pahl Tobias , Lehmann Peter
Published: August 2024

Coherence scanning interferometry is a widely used optical topography measurement technique, which can achieve axial resolutions in the sub-nanometer regime. Nevertheless, in the lateral dimension it is inherently diffraction limited and multiple problems arise when approaching this limit. Especially for challenging surface topographies like steep slopes or small grating periods measurement artifacts start to cause massive deviations in the 3D reconstruction of the surface due to the increased influence of noise on increasingly weak signals. In this study we present an illumination approach for Linnik-type CSI, which highlights oblique incident angles of the illuminating light cone in high numerical aperture (0.95) systems. It is demonstrated, that this approach can significantly improve the signal-to-noise ratio for measurements at steep surface slopes and therefore increase the subsequent surface reconstruction.