bluuebunny/crossref_metadata_2025 huggingface dataset:
Deep reaction network exploration of glucose pyrolysis
Authors: Zhao Qiyuan , Savoie Brett M.
Published: August 2023

Resolving the reaction networks associated with biomass pyrolysis is central to understanding product selectivity and aiding catalyst design to produce more valuable products. However, even the pyrolysis network of relatively simple

β

-D-glucose remains unresolved due to its significant complexity in terms of the depth of the network and the number of major products. Here, a transition-state-guided reaction exploration has been performed that provides complete pathways to most significant experimental pyrolysis products of

β

-D-glucose. The resulting reaction network involves over 31,000 reactions and transition states computed at the semiempirical quantum chemistry level and approximately 7,000 kinetically relevant reactions and transition states characterized with density function theory, comprising the largest reaction network reported for biomass pyrolysis. The exploration was conducted using graph-based rules to explore the reactivities of intermediates and an adaption of the Dijkstra algorithm to identify kinetically relevant intermediates. This simple exploration policy surprisingly (re)identified pathways to most major experimental pyrolysis products, many intermediates proposed by previous computational studies, and also identified new low-barrier reaction mechanisms that resolve outstanding discrepancies between reaction pathways and yields in isotope labeling experiments. This network also provides explanatory pathways for the high yield of hydroxymethylfurfural and the reaction pathway that contributes most to the formation of hydroxyacetaldehyde during glucose pyrolysis. Due to the limited domain knowledge required to generate this network, this approach should also be transferable to other complex reaction network prediction problems in biomass pyrolysis.
β-lapachone regulates mammalian inositol pyrophosphate levels in an NQO1- and oxygen-dependent manner
Authors: Eisenbeis Verena B. , Qiu Danye , Gorka Oliver , Strotmann Lisa , Liu Guizhen , Prucker Isabel , Su Xue Bessie , Wilson Miranda S. C. , Ritter Kevin , Loenarz Christoph , Groß Olaf , Saiardi Adolfo , Jessen Henning J.
Published: August 2023

Inositol pyrophosphates (PP-InsPs) are energetic signaling molecules with important functions in mammals. As their biosynthesis depends on ATP concentration, PP-InsPs are tightly connected to cellular energy homeostasis. Consequently, an increasing number of studies involve PP-InsPs in metabolic disorders, such as type 2 diabetes, aspects of tumorigenesis, and hyperphosphatemia. Research conducted in yeast suggests that the PP-InsP pathway is activated in response to reactive oxygen species (ROS). However, the precise modulation of PP-InsPs during cellular ROS signaling is unknown. Here, we report how mammalian PP-InsP levels are changing during exposure to exogenous (H
2
O
2
) and endogenous ROS. Using capillary electrophoresis electrospray ionization mass spectrometry (CE-ESI-MS), we found that PP-InsP levels decrease upon exposure to oxidative stressors in HCT116 cells. Application of quinone drugs, particularly β-lapachone (β-lap), under normoxic and hypoxic conditions enabled us to produce ROS in cellulo and to show that β-lap treatment caused PP-InsP changes that are oxygen-dependent. Experiments in MDA-MB-231 breast cancer cells deficient of NAD(P)H:quinone oxidoreductase-1 (NQO1) demonstrated that β-lap requires NQO1 bioactivation to regulate the cellular metabolism of PP-InsPs. Critically, significant reductions in cellular ATP concentrations were not directly mirrored in reduced PP-InsP levels as shown in NQO1-deficient MDA-MB-231 cells treated with β-lap. The data presented here unveil unique aspects of β-lap pharmacology and its impact on PP-InsP levels. The identification of different quinone drugs as modulators of PP-InsP synthesis will allow the overall impact on cellular function of such drugs to be better appreciated.
The effectiveness of moderating harmful online content
Authors: Schneider Philipp J. , Rizoiu Marian-Andrei
Published: August 2023

In 2022, the European Union introduced the Digital Services Act (DSA), a new legislation to report and moderate harmful content from online social networks. Trusted flaggers are mandated to identify harmful content, which platforms must remove within a set delay (currently 24 h). Here, we analyze the likely effectiveness of EU-mandated mechanisms for regulating highly viral online content with short half-lives. We deploy self-exciting point processes to determine the relationship between the regulated moderation delay and the likely harm reduction achieved. We find that harm reduction is achievable for the most harmful content, even for fast-paced platforms such as Twitter. Our method estimates moderation effectiveness for a given platform and provides a rule of thumb for selecting content for investigation and flagging, managing flaggers’ workload.
Estimating conflict losses and reporting biases
Authors: Radford Benjamin J. , Dai Yaoyao , Stoehr Niklas , Schein Aaron , Fernandez Mya , Sajid Hanif
Published: August 2023

Determining the number of casualties and fatalities suffered in militarized conflicts is important for conflict measurement, forecasting, and accountability. However, given the nature of conflict, reliable statistics on casualties are rare. Countries or political actors involved in conflicts have incentives to hide or manipulate these numbers, while third parties might not have access to reliable information. For example, in the ongoing militarized conflict between Russia and Ukraine, estimates of the magnitude of losses vary wildly, sometimes across orders of magnitude. In this paper, we offer an approach for measuring casualties and fatalities given multiple reporting sources and, at the same time, accounting for the biases of those sources. We construct a dataset of 4,609 reports of military and civilian losses by both sides. We then develop a statistical model to better estimate losses for both sides given these reports. Our model accounts for different kinds of reporting biases, structural correlations between loss types, and integrates loss reports at different temporal scales. Our daily and cumulative estimates provide evidence that Russia has lost more personnel than has Ukraine and also likely suffers from a higher fatality to casualty ratio. We find that both sides likely overestimate the personnel losses suffered by their opponent and that Russian sources underestimate their own losses of personnel.
Triple-negative breast tumors are dependent on mutant p53 for growth and survival
Authors: Dibra Denada , Moyer Sydney M. , El-Naggar Adel K. , Qi Yuan , Su Xiaoping , Lozano Guillermina
Published: August 2023

The
TP53
tumor suppressor gene is mutated early in the majority of patients with triple-negative breast cancer (TNBC). The most frequent
TP53
alterations are missense mutations that contribute to tumor aggressiveness. We developed an autochthonous somatic K14-Cre driven TNBC mouse model with p53R172H and p53R245W mutations in which mutant p53 can be toggled on and off genetically while leaving the tumor microenvironment intact and wild-type for p53. These mice develop TNBCs with a median latency of 1 y. Deletion of mutant p53R172H or p53R245W in vivo in these tumors blunts their tumor growth and significantly extends survival of mice. Downstream analyses revealed that deletion of mutant
Trp53
activated the cyclic GMP–AMP Synthase–Stimulator of Interferon Genes pathway but did not cause apoptosis implicating other mechanisms of tumor regression. Furthermore, we determined that only tumors with stable mutant p53 are dependent on mutant p53 for growth.
Molding a PI(3,5)P2 biosensor
Authors: Weckerly Claire C. , Hammond Gerald R.V.
Published: August 2023

The lipid phosphatidylinositol 3,5-bisphosphate—PI(3,5)P2—is known to be a key regulator of cellular traffic in health and disease, but its cellular localization was somewhat enigmatic until now, with the discovery of a new PI(3,5)P2 biosensor reported in this issue of JCB by Vines et al. (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202209077).
Epilepsy-associated SCN2A (NaV1.2) variants exhibit diverse and complex functional properties
Authors: Thompson Christopher H. , Potet Franck , Abramova Tatiana V. , DeKeyser Jean-Marc , Ghabra Nora F. , Vanoye Carlos G. , Millichap John J. , George Alfred L.
Published: August 2023

Pathogenic variants in voltage-gated sodium (NaV) channel genes including SCN2A, encoding NaV1.2, are discovered frequently in neurodevelopmental disorders with or without epilepsy. SCN2A is also a high-confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function variants cause neonatal-onset epilepsy, whereas loss-of-function variants are associated with ASD and ID. However, this framework was derived from a limited number of studies conducted under heterogeneous experimental conditions, whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of SCN2A variants using automated patch-clamp recording to demonstrate the validity of this method and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common variants using two alternatively spliced isoforms of NaV1.2 expressed in HEK293T cells. Automated patch-clamp recording provided a valid high throughput method to ascertain detailed functional properties of NaV1.2 variants with concordant findings for variants that were previously studied using manual patch clamp. Many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-functions that are difficult to classify by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of variants with greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor. This approach offers an enhanced ability to discern relationships between channel dysfunction and neurodevelopmental disorders.
30 years in: Quo vadis generalized uncertainty principle?
Authors: Bosso Pasquale , Gaetano Luciano Giuseppe , Petruzziello Luciano , Wagner Fabian
Published: August 2023

According to a number of arguments in quantum gravity, both model-dependent and model-independent, Heisenberg’s uncertainty principle is modified when approaching the Planck scale. This deformation is attributed to the existence of a minimal length. The ensuing models have found entry into the literature under the term generalized uncertainty principle. In this work, we discuss several conceptual shortcomings of the underlying framework and critically review recent developments in the field. In particular, we touch upon the issues of relativistic and field theoretical generalizations, the classical limit and the application to composite systems. Furthermore, we comment on subtleties involving the use of heuristic arguments instead of explicit calculations. Finally, we present an extensive list of constraints on the model parameterβ, classifying them on the basis of the degree of rigor in their derivation and reconsidering the ones subject to problems associated with composites.
Theoretical predictions and electronic properties of thiolate-protected gold nanocluster: Au44(SR)32
Authors: Sun Yuanze , Yu Xueke , Xu Wenwu , Su Yan , Zhao Jijun
Published: August 2023

Thiolate-protected gold nanoclusters have received extensive attention both experimentally and theoretically due to their excellent physical and chemical properties. However, comprehending the geometric structure of thiolate-protected gold nanoclusters remains a challenging task. Predicting the structural configuration of these ligand-protected gold nanoclusters can enhance our understanding of this class of materials. Due to the current lack of knowledge regarding the structure of Au44(SR)32, we employed the grand unified model (GUM) for gold core stacking and the ring model to describe interfacial interactions between gold cores and the protection motifs. Based on these models, we successfully predicted the geometric structure of Au44(SR)32 clusters and demonstrated partial reproducibility between the calculated absorption spectra and experimental results. Furthermore, by analyzing the energy levels and molecular orbitals, we have identified that the absorption spectra of Au44(SR)32 arise from d→d and d→sp transitions, with the low-energy state primarily resulting from Au44-to-core transitions and the high-energy state from Au44-to-ligand transitions. These findings not only enhance our understanding of Au44(SR)32 clusters but also validate the effectiveness and applicability of GUM and ring model in predicting stable structures of thiolate-protected gold nanoclusters.
Inverse design of transmission-type linear-to-circular polarization control metasurface based on deep learning
Authors: Hu Yanwen , Ma Yaodong , Zhang Tingrong , Li Shoudong , Chen Xiaoqiang
Published: August 2023

To solve the time-consuming and complex design problems, the deep learning method is used to realize the inverse predictive design of a transmission-type linear-to-circular polarization control metasurface (TLCPCM). Firstly, the target-generation neural network model (TGNNM) is constructed based on a fully connected neural network. The model selects the critical features of the required electromagnetic performance as design targets, and maps low-dimensional design targets to high-dimensional electromagnetic performance. Secondly, taking the output data of the TGNNM as input data, an inverse-mapping neural network model (IMNNM) is constructed by a convolutional neural network. The prediction performance of the IMNNM is compared with two other inverse-mapping models. The research results show that the IMNNM outperforms the other two networks. Finally, combining TGNNM and IMNNM, four sets of TLCPCM structural parameters are predicted. The research results show that the electromagnetic performances of the metasurface determined by the predicted structural parameters are generally consistent with the given design targets. On this basis, one experimental sample is manufactured. The measurement results are consistent with the simulation results. The research results demonstrate the validity and feasibility of the inverse predictive design method proposed in this paper.
Analytical input-output modelling of surface dielectric barrier discharge plasma actuator
Authors: Nesaeian M , Homaeinezhad M R
Published: August 2023

Surface dielectric barrier discharge (SDBD) actuators are a type of asymmetric dielectric barrier discharge (DBD) actuator that can be used to generate ions and produce thrust for near-space vehicles. In this paper, a physics-based model for SDBD produced thrust is developed that accounts for geometric and environmental variation between SDBDs. The presented SDBD analytical model (SDBD-AM) is based on models for parallel-plate DBDs but accounts for the ‘virtual electrode’ resulting from changing plasma length that is particular to SDBDs. To validate the model, thrust measurements from 12 different configurations from previous studies were used, and the mean absolute percentage error (MAPE) between each configuration and SDBD-AM was determined. The observed effects on the model were attributed to structural effects including electrode width, electrode spacing, dielectric, and environmental effects including pressure, and the apparent uncertainties are different for each effect. As a result, it was obtained that the MAPE between SDBD-AM and the experimental data for different structures is 11%, and for different pressures, it is 12%. The body force field has been simulated using SDBD-AM and a distribution function in COMSOL software, and the body force profile near the exposed electrode has been validated with a previous numerical model. This model can be used for the design and optimization of SDBD actuators and also in the design of control systems such as spacecraft attitude control in order to increase the accuracy and performance of the controller.
Enhancing photoelectrocatalytic activity and stability of p-Cu2O photocathode through n-TiO2 coating for improved H2 evolution reaction
Authors: Le Hoang V , Ung Thuy T D , Tran Phong D , Mai Huy V , Do Bich D , Nguyen Liem Q
Published: August 2023

This article presents a novel approach to improve both the photoelectrocatalytic activity and stability of the p-Cu2O photocathode. The approach involves the coating of an n-type TiO2 layer using e-beam evaporation with precise controllability of the coating thickness onto the p-type Cu2O electrode, forming a TiO2/Cu2O p/n heterojunction. Such a p/n junction enhances the photoelectrocatalytic activity of the Cu2O electrode by promoting the separation of the photo-generated charge carriers. Additionally, the large bandgap TiO2 coating layer serves as protection, reducing the photocorrosion of Cu2O, thereby improving the stability of the electrode. The n-TiO2/p-Cu2O photocathode shows superior photoelectrochemical H2 evolution activity in comparison to the pristine p-Cu2O photocathode. We have found that the thickness and annealing temperature of TiO2 influence strongly the photocurrent and stability of the resultant TiO2/Cu2O photocathode. The best TiO2/Cu2O photocathode was achieved by coating a 50 nm thick TiO2 layer onto the Cu2O, followed by annealing at 350 °C. This configuration exhibited a large onset photovoltage of 0.58 V vs RHE and a catalytic current density of ∼0.9 mA·cm‒2 at 0 V vs RHE in a pH 7 phosphate buffer, under standard 1 Sunlight illumination.
Exploration on structural stability, electronic and optical properties of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin film and nanowire photocathode surface
Authors: Tian Jian , Liu Lei , Lu Feifei , Zhangyang Xingyue
Published: August 2023

To explore effects of surface activation on AlGaN-based photocathode, this paper analyzes in detail the structural stability, charge transfer, band structure, density of states, absorption coefficient and reflectivity of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin films and nanowires by using first-principles. Our results reveal that adsorption energy of Al0.5Ga0.5N thin films and nanowires adsorbed by Cs will gradually increase as Cs coverage increases, and structural stability will be weakened. Cs-adsorbed thin film surfaces are more stable than nanowire when Cs coverage is same. Cs/O co-adsorbed Al0.5Ga0.5N systems are more stable under high Cs coverage. And Cs/O co-adsorbed Al0.5Ga0.5N possess the most stable structure when the ratio of Cs to O is 2:1. Band structure and density of states imply that Cs and O adsorption introduce new energy levels, which are derived from s, p orbitals of Cs and s orbitals of O, respectively. Furthermore, only when the Cs/O ratio is 2:1, the work function of Al0.5Ga0.5N thin film is lower than that of Cs-only adsorption, which is conducive to electron escape and improving quantum efficiency. Results of optical properties show that Cs activation and Cs/O activation can greatly improve the optical performance of Al0.5Ga0.5N.
High-speed and dynamic measurement of the diffraction efficiency of a grating in a wide wavelength range
Authors: Wang Shenghao , Wang Zhendong , He Zhiping
Published: August 2023

Approximate 5 min are needed to obtain diffraction efficiency of a grating in a wavelength range with 151 sampling points by the currently widely used measurement technique. The time-consuming nature restricts its usage in many dynamic measurements. To this end, we developed a fast measurement technique, and the corresponding measurement is completed in a high speed within 1 s. Meanwhile, dynamic measurement of the efficiency of a grating from 600 nm to 900 nm during a heating procedure is successfully carried out. Our technique could find applications in other circumstances where high-speed measurement is needed.
The research on fault diagnosis of rolling bearing based on current signal CNN-SVM
Authors: Wang Xinghua , Meng Runxin , Wang Guangtao , Liu Xiaolong , Liu Xiaohong , Lu Daixing
Published: August 2023

This article proposes a novel approach to address the issues of low accuracy in fault diagnosis and the difficulty in installing sensors on rolling bearings in mechanical and electrical equipment systems. To accomplish fault diagnosis of rolling bearings, a network structure algorithm based on convolutional neural network (CNN) and support vector machine (SVM) is presented, which incorporates the electric motor current signal. Firstly, the collected electric motor current signal is subjected to a wavelet filter with a soft-hard threshold to eliminate the noise. Secondly, the processed data is fed as input to a one-dimensional CNN to perform feature extraction and dimensionality reduction. Finally, the dimensionality-reduced features are processed by a SVM to diagnose rolling bearing faults. The research results indicate that the proposed method significantly improves the accuracy of rolling bearing fault diagnosis compared to other approaches, with an accuracy of up to 99.01%. This study introduces an innovative approach that can be applied to the field of rolling bearing fault diagnosis, offering valuable insights for research and application in this domain.
Manifold learning-assisted sparse filtering method for machinery fault diagnosis
Authors: Wang Qian , Peng Demin , Jiang Xingxing , Song Qiuyu , Zhu Zhongkui
Published: August 2023

Sparse filtering (SF) has received considerable attentions in the machinery fault diagnosis thanks to its ability to extract the fault-related features using their sparsity. However, the existing SF methods have dilemmas with the empirical selection of model parameters, the loss of fault-related information caused by a screening way for the target mode, and the singularity of results induced by some large-amplitude random impulses (LARIs). Hence, a manifold learning-assisted SF method is proposed for machinery fault-related feature enhancement in this study. First, an improved intrinsic component filtering (ICF) is presented for extracting the multiple modes with feature enhancement, where the parameters of ICF are adaptively determined by using the optimization object to avoid the empirical selection of parameters. Second, the manifold learning is introduced to compress the enhanced multiple modes to overcome the loss of fault-related information; thus the intrinsic manifolds are obtained for disclosing the buried fault-related features and suppressing the band-in noise. Third, an adaptively weighting strategy for these intrinsic manifolds is constructed to obtain a final representative mode for conducting the machinery fault diagnosis. Meanwhile, the LARIs coupled with intrinsic manifolds are calibrated according to their statistical information to resolve the singularity of the representative features. Simulation and experiments show that the proposed method is more effective in extracting fault-related features than some existing methods.
Oxygen-doped NiCoP derived from Ni-MOFs for high performance asymmetric supercapacitor
Authors: Liu Yan , Fan Xiaoyan , Zhang Zikun , Li Chun , Zhang Shuaiyi , Li Zhenjiang , Liu Lin
Published: August 2023

Oxygen doping strategy is one of the most effective methods to improve the electrochemical properties of nickel–cobalt phosphide (NiCoP)-based capacitors by adjusting its inherent electronic structure. In this paper, O-doped NiCoP microspheres derived from porous nanostructured nickel metal–organic frameworks (Ni-MOFs) were constructed through solvothermal method followed by phosphorization treatment. The O-doping concentration has a siginificant influence on the rate performance and cycle stability. The optimized O-doped NiCoP electrode material shows a specific capacitance of 632.4 F-g−1 at 1 A-g−1 and a high retention rate of 56.9% at 20 A g−1. The corresponding NiCoP-based asymmetric supercapacitor exhibits a high energy density of 30.1 Wh kg−1 when the power density is 800.9 W kg−1, and can still maintain 82.1% of the initial capacity after 10 000 cycles at 5 A g−1.
On zonal steady solutions to the 2D Euler equations on the rotating unit sphere
Authors: Nualart Marc
Published: August 2023

The present paper studies the structure of the set of stationary solutions to the incompressible Euler equations on the rotating unit sphere that are near two basic zonal flows: the zonal Rossby–Haurwitz solution of degree 2 and the zonal rigid rotation

Y

1
0

along the polar axis. We construct a new family of non-zonal steady solutions arbitrarily close in analytic regularity to the second degree zonal Rossby–Haurwitz stream function, for any given rotation of the sphere. This shows that any non-linear inviscid damping to a zonal flow cannot be expected for solutions near this Rossby–Haurwitz solution. On the other hand, we prove that, under suitable conditions on the rotation of the sphere, any stationary solution close enough to the rigid rotation zonal flow

Y

1
0

must itself be zonal, witnessing some sort of rigidity inherited from the equation, the geometry of the sphere and the base flow. Nevertheless, when the conditions on the rotation of the sphere fail, the set of solutions is much richer and we are able to prove the existence of both explicit stationary and travelling wave non-zonal solutions bifurcating from

Y

1
0

, in the same spirit as those emanating from the zonal Rossby–Haurwitz solution of degree 2.
Students’ perceptual practices with real and virtual images
Authors: Isik Hakan
Published: August 2023

This study examined how university students learn real and virtual images using vision-based perception cues such as binocular parallax, monocular parallax, binocular fuzziness, monocular fuzziness, and convergence. Two activities on the cues were conducted with university students. In the pre-activity, they learned about the perceptual cues and practiced each cue without using a lens or mirror. Then, four setups with convex lenses and concave mirrors were designed, enabling the study of the clues, and in the main activity, the students practiced each cue on the setups. Their experiences in the main activity were acquired through written reports, student observations, and interviews. Following the activities, the students related their perceptual experiences to their prior knowledge of images. Additionally, the students were questioned regarding their opinions on the use of five perceptual cues as image-learning strategies. The students found that the observation of binocular parallax in a lens or mirror represents a real image. They identified the relative positions of real and virtual images and their objects with the help of monocular parallaxes. They also connected their understanding of optics to the perceptual cues that real images appeared in front of mirrors and on the opposite side of the object in lenses, but virtual images appeared behind mirrors and on the object side of lenses. Conclusions were suggested for optics instructions.
Human body and physics: combined use of simulations and hands-on experiments to explain the quadricep muscle exercise
Authors: Mohottala Hashini , Althani Basim , Higgins Brent
Published: August 2023

We report the combined use of simulations and hands-on activities in a physics course designed to teach mechanics and the human body. Most students in the class are majoring in physical therapy or sports medicine. Although demonstrations, animations, and visual aids can tremendously help in teaching a course like this, we have access only to a few due to the novelty of the course. Therefore, to demonstrate the physics behind a physical therapy used to exercise the quadriceps muscle, we built a prototype that follows the function of a human knee. There we applied a force to the lower part of the leg (ankle area) and tracked the resultant force transferred into the quadriceps muscle. While this hands-on activity help students understand how torque balanced the system’s static equilibrium, the simulation we developed using JavaScript shows how the equilibrium is held even when the leg is moving. The simulation creates a unique, user-friendly atmosphere and invites students to try it by altering the parameters and modifying the program.
OH density, flux and loss probability measurements in a room temperature atmospheric pressure surface discharge by microscopic laser induced fluorescence
Authors: Wang Jianan , Bruggeman Peter J
Published: August 2023

Many applications involving atmospheric pressure plasma-substrate interactions are enabled by the large fluxes of short-lived reactive species such as OH radicals to the substrate, nonetheless, the accurate measurement of radical densities and fluxes at substrates at atmospheric pressure has received little attention to date, particularly for surface ionization waves. We report the measurement of the OH density distribution in a surface discharge on a fused silica (quartz) substrate generated by an impinging atmospheric pressure plasma jet in dry and humid helium. The OH density is measured by microscopic laser induced fluorescence with a spatial resolution of 10 µm in the direction perpendicular to the quartz substrate. The measured OH diffusive flux varied for the investigated experimental conditions by almost three orders of magnitude and had a maximum value of 1.7 × 1015 cm−2 s−1. The corresponding surface loss probability of OH on the quartz surface was determined to be ∼0.01. The high spatial resolution was required to accurately resolve the near surface gradient of OH radicals.
Performance of high-temperature superconducting REBCO coated conductors under synchrotron irradiation for future circular colliders
Authors: Krkotić Patrick , Traver Oriol , Tagdulang Nikki , Calatroni Sergio , Manuel O’Callaghan Juan , Pont Montse
Published: August 2023

The influence of medium-to-high energy synchrotron radiation (SR) (≈10–100 keV) produced by the ALBA Synchrotron Light Source on state-of-the-art REBCO coated conductors (CCs) has been studied to assess the feasibility of using high-temperature superconductors for the beam screen of future circular colliders. Long-term irradiation studies were conducted with ex-situ surface resistance testing by using a dielectric resonator. In addition, a cryogenic test system was established for in-situ measurements of the critical temperature and surface impedance of REBCO-CCs during synchrotron irradiation, with intensities similar to or above those generated by proton beams circulating in the vacuum chamber in the future circular collider hadron–hadron design. It is shown that the SR impact does not introduce any macroscopic defects that permanently alter the critical temperature or surface impedance of REBCO-CCs. However, the most significant effect of SR is a transient increase in the REBCO’s surface impedance. This effect is likely caused by heat, as the material returns to its original impedance values once the radiation exposure stops. The correlation between the time structure of the SR and the possibility of suppressing the Cooper pairing mechanism is also discussed.
Dynamic behavior of skyrmion collision: spiral and breath
Authors: Shi Shengbin , Zhao Yunhong , Sun Jiajun , Hou Xu , Zhou Haomiao , Wang Jie
Published: August 2023

A magnetic skyrmion is a particle-like topological soliton, which is an ideal candidate for developing high-density storage and logic devices due to its nonvolatility and tunability. In view of the particle motion characteristics of skyrmion, different skyrmions in a material inevitably interact in the form of short-range repulsion and long-range attraction. In this work, the dynamic characteristics of skyrmion collision in a ferromagnetic Co thin film are investigated by using micromagnetic simulations. It is found that the dynamic behavior of skyrmion after collision is highly dependent on the size of the strip, the initial velocity of skyrmion and magnetic damping constant. For the collision of two skyrmions, when the strip width exceeds the critical value, the skyrmions form a pair and rotate counterclockwise in the form of spiral and breath. It is interesting that the rotation and breath of skyrmions keep the same periodicity under the negligible damping, and the frequency increases with the increase of the initial velocity of skyrmion. Further, the collision of a system of three skyrmions reveals that they interact in pairs to form closed periodic trajectories. The results of the present work not only give an insight into the multi-skyrmion dynamics, but also provide guidance for the development of spintronic devices based on multi-skyrmion motion.
The Hawking energy in a perturbed Friedmann-Lemaître universe
Authors: Stock Dennis , Di Dio Enea , Durrer Ruth
Published: August 2023

Hawking's quasi-local energy definition quantifies the energy enclosed by a spacelike 2-sphere in terms of the amount of lightbending on the sphere caused by the energy distribution inside the sphere. This paper establishes for the first time a direct connection between the formal mathematical definition of a quasi-local energy and observations, in the context of cosmological perturbation theory. This is achieved by studying the Hawking Energy of spherical sections of the past lightcone of a cosmic observer in a perturbed Friedmann-Lemaître spacetime. We express the Hawking Energy in terms of gauge-invariant perturbation variables and comment on the cosmic observables needed to in principle measure it. We then calculate its angular power spectrum and interpret its contributions.
Stochastic gravitational wave background from stellar origin binary black holes in LISA
Authors: Babak Stanislav , Caprini Chiara , Figueroa Daniel G. , Karnesis Nikolaos , Marcoccia Paolo , Nardini Germano , Pieroni Mauro , Ricciardone Angelo , Sesana Alberto , Torrado Jesús
Published: August 2023

We use the latest constraints on the population of stellar origin binary black holes (SOBBH) from LIGO/Virgo/KAGRA (LVK) observations, to estimate the stochastic gravitational wave background (SGWB) they generate in the frequency band of LISA. In order to account for the faint and distant binaries, which contribute the most to the SGWB, we extend the merger rate at high redshift assuming that it tracks the star formation rate. We adopt different methods to compute the SGWB signal: we perform an analytical evaluation, we use Monte Carlo sums over the SOBBH population realisations, and we account for the role of the detector by simulating LISA data and iteratively removing the resolvable signals until only the confusion noise is left. The last method allows the extraction of both the expected SGWB and the number of resolvable SOBBHs. Since the latter are few for signal-to-noise ratio thresholds larger than five, we confirm that the spectral shape of the SGWB in the LISA band agrees with the analytical prediction of a single power law. We infer the probability distribution of the SGWB amplitude from the LVK GWTC-3 posterior of the binary population model: at the reference frequency of 0.003 Hz it has an interquartile range of h2ΩGW(f= 3 × 10-3Hz) ∈ [5.65, 11.5] × 10-13, in agreement with most previous estimates. We then perform a MC analysis to assess LISA's capability to detect and characterise this signal. Accounting for both the instrumental noise and the galactic binaries foreground, with four years of data, LISA will be able to detect the SOBBH SGWB with percent accuracy, narrowing down the uncertainty on the amplitude by one order of magnitude with respect to the range of possible amplitudes inferred from the population model. A measurement of this signal by LISA will help to break the degeneracy among some of the population parameters, and provide interesting constraints, in particular on the redshift evolution of the SOBBH merger rate.
Considering the heavy-quark distribution functions at low x
Authors: Karampur Elham , Boroun G R
Published: August 2023

In this paper, we investigate the behavior of charm and bottom distribution functions at low x with respect to the parametrization of the gluon distribution function in the framework of the nonlinear Gribov–Levin–Ryskin–Mueller–Qiu, Zhu-Ruan-Shen (GLR-MQ-ZRS) evolution equation. Also, we solve the GLR-MQ-ZRS equation using the parametrization behavior of the gluon distribution function. The computed results are compared with the NNPDF3.0, CT14 and GRV92 collaborations.
A High-Temperature Superconducting Wideband Bandpass Filter at the L Band for Radio Astronomy
Authors: Zhu Xinyu , Li Jianbin , Lu Boyu , Wei Bin , Jiang Yifan , Jiang Linan , Hu Chao
Published: August 2023

In order to ensure the normal operation of radio astronomy observations, an extremely sensitive receiver system needs to be equipped in front of the large radio telescope. An 8-pole wideband high-temperature superconducting (HTS) filter using a Coplanar Spiral Resonator Structure with a passband of 1160∼1670 MHz is developed to suppress strong radio interference. The filter is fabricated on a 36 mm × 14 mm YBCO HTS film, which is deposited on a 0.5 mm thick MgO substrate. The minimum insertion loss measured in the liquid nitrogen temperature region is 0.03 dB, and the first parasitic passband appears at 2600 MHz. The measured results are in good agreement with the simulations. The filter can be used in radio telescope receivers for the observation of neutral hydrogen and pulsars, as well as in high-sensitivity satellite navigation instruments.
Mathematical simulation of backwater and velocity distribution around tandem cylindrical piles
Authors: Zhang Yong
Published: August 2023

Nowadays, with the extensive development and utilization of coastal engineering, the research on the flow field around pile groups is becoming more important. In this paper, the flow velocity and water level distribution around tandem cylindrical and rectangular piles are calculated and studied by the numerical simulation method based on delft3D. The results show that the water level of the piles in the front row of the tandem pile group increases greatly, and the influence of the rear row of the piles is small due to the shielding effect.
Design and Hydrodynamic Performance Analysis of Offshore Multi-Module Floating Docks
Authors: Fu Rong , Guo Jianting , Wu Renhao , Liu Haoran
Published: August 2023

This study presents a design scheme for a multi-module connected floating dock, comprising two configurations for the lower floating body: transverse and longitudinal floats. An articulated connection between the modules is also included. The hydrodynamic performance of the floating dock with these two configurations is compared and analyzed by taking the South China Sea as an example. Frequency and time-domain analysis methods are employed, considering the coupling between the mooring and the multi-module floating dock. The results indicate that, under the condition of both cross waves and oblique waves, the transverse float configuration exhibits superior motion response performance in all degrees of freedom compared to the longitudinal float configuration, particularly in terms of roll performance. Furthermore, the maximum mooring tension and connection structure load for the transverse float configuration are lower than those for the longitudinal float configuration, resulting in superior overall hydrodynamic performance.
Numerical simulation on tar cracking behavior under the Brown’s Gas atmosphere
Authors: Yang Shuo , Wang Shaohui , Cui Jie , Fu Yudong , Jiang Xin , Zhang Yupeng , Yan Zeyi
Published: August 2023

The Chemkin® calculation software platform was used in this paper, using benzene, toluene, and phenol as tar model compounds, and the cracking law of Brown’s gas to tar model compounds was studied by sensitivity analysis at the temperature of 892.5 K and 1130.5 K, respectively. The results showed that the active free radicals of -H and -O in Brown’s gas promote the breaking of methyl bonds and hydrogen bonds, and the formation of phenoxy ions. With the increasing temperature, the secondary products also promote the tar components cracking. Brown’s gas plays an obvious catalytic role in tar cracking, reducing the activation energy of the reaction, and resulting in a decrease in cracking reaction temperature. In addition to active free radicals of Brown’s gas involved in tar cracking, the phenoxy ions also indirectly affect the tar cracking rate.
Calculation of transportation resistance of different soils in Dredging Engineering
Authors: Luo Jiacheng , Yuan Chaozhe , Zhu Ping , Hao Yuchi , Wang Sheng
Published: August 2023

Pipeline transportation is a process of continuous balance between pumping pressure and pipeline resistance. Therefore, accurate calculation of pipeline transportation resistance can optimize the accuracy of the pump model and working parameters. The slurry transported in the dredging project is complicated, and the dredged soil in different regions is quite different resulting in different motion states in the transportation process. Different types of flow patterns are suitable for different resistance calculation models. In this paper, according to the actual dredger filling project, the real transmission resistance of the project is obtained by means of pipeline pressure monitoring data analysis. Three different transmission resistance calculation formulas of Wang Shaozhou formula, Durand formula and DHLLDV model are used to compare the clay, fine sand and medium coarse sand. The calculation results show that the Durand formula is the best for calculating the transmission resistance of medium coarse sand; the DHLLDV model is better for calculating the transport resistance of fine silt; the error between the DHLLDV model of clay transport resistance and Wang Shaozhou formula is small. In this paper, the calculation error analysis of three different kinds of soil is carried out, and the best calculation formula for three types of soil is obtained. The accurate calculation method of theoretical formula in dredging and filling projects is obtained, and the reference table of three kinds of soil for transportation resistance is proposed, which provides a reference for dredging project transportation.
A Hierarchical Maintenance Method for Power System Transmission and Substation Multi-Equipment Operation Status Considering Equipment Service Age
Authors: Jiang Enze , Hu Ruixing , Zhang Yikang , Gong Zhengpeng , Sun Jingqi
Published: August 2023

The current conventional maintenance methods for transmission and substation operation equipment are mainly used to extract fault data features by combining micro-network algorithms to process equipment operation data. The lack of effective analysis of equipment fault characteristics leads to poor maintenance results. In this regard, a power system transmission and substation multi-device operation status hierarchical maintenance method considering the age of equipment service is proposed. By accessing the configuration network and interacting with the grid intelligent collection of data, network storage and parallel processing of data are realized. The characteristics of transmission and substation equipment operation data are analyzed and processed to build the maintenance system. In the experiments, the proposed method is validated for the effect of condition assessment. The experimental results show that when the proposed method is used to process the transmission and substation equipment, the condition assessment accuracy is high and it has a more desirable equipment maintenance performance.
Multi-type Adjustable Loads Aggregation Control Strategy for Industrial Parks
Authors: Liu Yu , Chen Jinchang , Yang Cheng , Miao Lu , Tang Yufeng , Yang Ping
Published: August 2023

China’s industrial parks are the concentration areas of industrial enterprises. The aggregate regulation and control of various types of adjustable loads in industrial parks are effective means to achieve the consumption of renewable energy. However, there are many types of adjustable loads, along with varying amounts and response characteristics, which makes it difficult to achieve unified regulation. In view of the regulation and control characteristics of multiple types of adjustable loads in industrial parks, the regulation and control models of short-term interruptible load, reducible load, translatable load, transferable load and distributed energy storage are established respectively in this paper, aiming at minimizing the regulation cost and maximizing the benefits of the regulation and control auxiliary services, and the aggregate regulation and control strategy of multiple types of adjustable loads in industrial parks is proposed based on the electricity market environment to support the high proportion of renewable energy consumption of the new power system. At the same time, it will obtain auxiliary service income for industrial users. The simulation results of the example show that the proposed strategy reduces the power consumption cost of industrial users and effectively increases the usage of renewable energy without affecting the production of enterprises.
Distribution Network Balance Method under High Proportion of Distributed Power Penetration Scenario
Authors: Tian Li , Liu Rundong , Liang Xiaochuan , Wang Fengxiao , Liu Fan , Yang Chao , Yu Haobo
Published: August 2023

With the rapid development of various subjects represented by distributed generation, how to implement power balance in a distribution network has become a research direction. The utilization efficiency of a distribution network can be improved by the bidirectional power flow of flexible resources. However, the traditional distribution network power balance method relies on historical data, making it challenging to determine the principle of new subject participation. It does not meet the requirements of bidirectional power flow balance and loses critical information such as complementary load characteristics. We believe that distribution network power prediction needs to transform from single load prediction to multi-resource prediction, from quantitative prediction to quantitative plus characteristic prediction. In comparison to the traditional methods, curve superposition can be better compatible with the research results of different new load forecasting topics and meet the needs of efficiency and precise network planning.
Application of a Modified Quantum-behaved Particle Swarm Optimization Algorithm for MPPT
Authors: Huang Ronggeng
Published: August 2023

Aiming at the characteristics of multiple power peaks of the photovoltaic array under non-homogeneous irradiance conditions, a modified quantum-behaved particle swarm optimization algorithm (MQPSOA) for maximum power point (MPP) tracking is provided. The MQPSOA directly controls the duty ratio and dynamically adjusts parameters during its operation. The final results of the photovoltaic system experiment illustrate that the MQPSOA exhibits good performance in the global search of the MPP. It has a fast search rate and small power fluctuation in comparison with particle swarm optimization.
A Gaussian multi-scale mixture model-based outlier-robust Kalman filter
Authors: Huang Wei , Fu Hongpo , Li Yu , Ming Ruichen , Zhang Weiguo
Published: August 2023

In many practical applications, the unknown non-stationary heavy-tailed distributed process and measurement noises (HTPMNs) are prone to occur due to inaccurate noise prior and stochastic outliers. To achieve the state estimation under this situation, a new outlier-robust Kalman filter based on Gaussian multi-scale mixture model (GMSMM-ORKF) is proposed in this paper. First, a new GMSMM is designed to model the one-step prediction and measurement likelihood probability density functions. Then, the hierarchical prior presentation on the mixture probability vectors and scale parameters are built. Furthermore, employing the variational Bayesian (VB) inference, a GMSMM-ORKF is derived. Finally, a classical target tracking model and real navigation experiment are utilized to demonstrate the effectiveness of the proposed filter.