bluuebunny/crossref_metadata_2025 huggingface dataset:
Parametric investigation of inlet flow cooling on axial compressor performance in different operating conditions
Authors: Abbasi Sarallah , Salmani Moein
Published: February 2025

Using the wet compression method improves the gas turbines' performance. It has been successfully incorporated into numerous industrial gas turbines within the power generation sector industry in recent years. The study focuses on the numerical simulation of fluid flow and the application of both dry and wet compression techniques in an axial compressor, specifically The National Aeronautics and Space Administration Rotor 37. The study investigates the impact of key parameters in the wet compression process, such as particle diameter and injection mass flow rate. The flow simulation within the compressor was conducted using the software ANSYS CFX using a stable and three-dimensional method. In wet compression, the discrete phase transition model was used, along with the application of active input forces from the continuous phase. The simulation results for dry and wet compression states were compared with experimental data, showing good agreement. The findings indicated that, under design conditions and near-stall, reducing the droplet size and increasing the injection mass flow rate significantly decreased the static temperature of the outflow. Therefore, it is not recommended to use this method in the operational conditions of choking in the compressor. The study revealed that the maximum stall margin is associated with the dry compression process, and injection reduces the stall margin in all conditions. The largest drop of 5.62% at the edge of the stall occurred with 1 μm droplets at an injection mass flow rate of 3%. Furthermore, the adiabatic efficiency saw its most significant rise with 1 μm droplets, showing a peak increase of 7.21% during near-stall conditions with a 3% mass flow rate. The compressor stable performance range was associated with an 18.31% decrease for 1 μm droplets at an injection rate of 3%.
A Ku-band phase-locked coaxial relativistic Cherenkov generator with low guiding magnetic field
Authors: Li Ying , Ju Jinchuan , Shu Ting , Zhang Wei , Zhou Yunxiao , Yao Hongtao
Published: February 2025

A Ku-band phase-locked coaxial relativistic Cherenkov generator with a low guiding magnetic field is presented. Owing to the use of the combined periodic double-corrugation slow-wave structure, the quasi-TEM mode exhibits a strong axial electric field at the center of the beam tunnel. As a result, the electron beam can achieve effective beam–wave interaction without proximity to the SWS surfaces, allowing the electron beam with a larger envelope and, therefore, reducing the demand for strong guiding magnetic fields. Two single-gap cascaded pre-modulation cavities are used to reduce the demand for the injected signal and to improve the power ratio of the output microwave to the input signal. Particle-in-cell simulation results show that, under a guiding magnetic field of 0.65 T, an injected signal with a power of 5 kW can lock the frequency and phase of a 966 MW output microwave, where the bandwidth is about 60 MHz and the phase instability is within ±2°. In addition, the efficiency is about 40%, and the power ratio of the output microwave to the input signal is ∼53 dB.
Evaluation of two inverted Nadarajah–Haghighi production lines via joint progressive type-II censoring with two physical applications
Authors: Alqasem Ohud A. , Elshahhat Ahmed , Abd Elwahab Maysaa Elmahi , Nassar Mazen
Published: February 2025

This study enables the simultaneous estimations of the unknown parameters of two inverted Nadarajah–Haghighi populations. The estimations are conducted using data collected from joint progressively type-II censored samples from the populations of interest. The estimations are based on the assumption that the parameters of the two populations are unknown and unequal. To achieve this, we use classical and Bayesian estimation methods to obtain point and interval estimates for the various unknown parameters. The maximum likelihood and approximate interval estimates are derived from the classical perspective. From the Bayesian perspective, both Bayes estimates and credible intervals are acquired using gamma prior distributions. The Bayes estimates are calculated using squared error loss and by sampling from the posterior distribution through the Markov chain Monte Carlo procedure. All point and interval estimates are validated through a simulation study. In addition, two physical applications are provided to demonstrate the practical significance of the methodologies employed.
Thermal structures on the water surface: Chaotic and regular trees
Authors: Zvonarev K. V. , Martyushev L. M.
Published: February 2025

The convective motion of water in a small horizontal layer is studied numerically. The bottom and side walls of the cuboid layer are heated, and from the upper surface, heat is removed, including through evaporation into the surrounding air, which is at atmospheric pressure and a temperature of 25 °C. A free-slip condition is set for fluid motion at the water–air boundary. The bottom temperature is 45 °C, while the temperature of the walls changes from 25 °C to 70 °C. In this system, with a symmetrical increase in the horizontal temperature gradient, successively replacing each other treelike thermal structures are found, which in time behave at first chaotically, then periodically and finally invariably. Respectively, these treelike structures change from irregular to regular in space. Self-organization of periodic structures in the absence of external periodic influences in a simple system, which is possible to observe in nature, is an unexpected result. The entropy production was calculated for each type of structure, and it was shown that this quantity is minimal if the side walls and the bottom of the fluid have the same temperature.
Particle trajectory and deposition in contraction–expansion flow fields using coupled large eddy simulation and discrete phase model
Authors: Mu Defang , Wang Mingjun , Guo Kailun , Zang Hang , Tian Wenxi , Su Guanghui , Qiu Suizheng
Published: February 2025

Flow channel contractions and expansions often lead to flow separation and accelerated fouling deposition, particularly around the tube support plate (TSP) in steam generators. This study employed large eddy simulation (LES) coupled with the discrete phase model (DPM) to analyze deposition mechanisms at various locations within these flow configurations. Simulation results were compared with Reynolds-averaged Navier–Stokes (RANS) models, with LES showing superior predictive accuracy, especially when sub-grid-scale turbulence effects were considered. A comprehensive analysis of near-wall flow behavior, particle trajectories, and deposition characteristics was conducted. Results indicate that fouling deposition at the TSP inlet is particularly severe, with a high risk of blockage. A deposition model specific to the TSP inlet was developed, showing that dimensionless deposition velocity initially increases and then decreases with increasing dimensionless relaxation time. For τp*<0.04, Vd+ increases proportionally to (τp*)1.18. In contrast, for 0.04≤τp*<2.1, centrifugal forces reduce deposition, following Vd+∝(τp*)−0.77. This study advances the understanding of hard fouling formation and offers strategies for mitigation in steam generators and similar systems.
Shear deformation characteristics and shear strength considering the interaction between joints and rock bridges
Authors: Wang Shicheng , Liu Hongliang , Gao Xin , Yang Xuxu , Li Liping , Chen Yuxue , Zhou Zhongxu , Tu Wenfeng
Published: February 2025

Nonpersistent joints that commonly exist in nonpersistent discontinuities exhibit complex shearing behavior due to the intervals between rock bridges. The influence of rock bridges on the bearing capacity of joints is difficult to determine due to two main factors: uncertainty of the proportion of the rock bridge area (or joint area) in terms of geometry and the resulting variation in normal stress distribution in terms of dynamics. As an innovative study, this paper investigates the effects of normal stress and joint persistence on the sequence of mobilization and stress distribution of rock bridges and joints by recording the deformation pattern of the two parts during a direct shear test. The test results show that the normal stress is not a weighted average according to the length of the joints and the rock bridge. Since the vertical deformation of joints is affected by the rock bridge, the normal stress borne by the rock bridge is greater than the weighted average. This difference changes the distribution of shear stress across the rock bridge and joints. On the basis of the Lajtai model, a shear strength model for nonpersistent joints that considers the interaction between rock bridges and joints was proposed, which shows agreement with the shear strength values obtained through experiments.
Research on multi-objective optimization of guide vane of reactor coolant pump based on genetic algorithm
Authors: Ye Daoxing , Wen Tian , Zhai Fengli , Liu Binhao , Deng Rui
Published: February 2025

This study investigates the impact of guide vane parameters on the performance of a reactor coolant pump (RCP). A mixed-flow RCP was selected for numerical simulation, with head and efficiency under design conditions as the optimization objectives. A genetic algorithm was employed to optimize the guide vane parameters of the RCP. The external characteristics, pressure distribution, and hydraulic loss of both the optimized and original pump models were analyzed. The optimized pump exhibited a 3.44 m increase in head and a 3.38% improvement in efficiency at the design flow rate. The pressure distribution in the optimized RCP model showed a significant reduction in the overall high-pressure area of the flow components at large flow conditions. At the 1.0Qd condition, the pressure distribution in the optimized model was more uniform, indicating more stable internal flow. Hydraulic loss of the guide vane and volute was significantly reduced in the optimized model. The overall performance of the optimized reactor coolant pump model has been improved.
Calculation and uncertainty analysis method for airfoil drag coefficient considering compressibility
Authors: Du Yufeng , Guo Qiuting , Wang Lulu , Zhu Jilong , Xiong Neng
Published: February 2025

In order to meet the need of evaluating the effectiveness of airfoil drag reduction design, the calculation and uncertainty analysis method for airfoil drag coefficient considering compressibility is studied. Based on the momentum conservation equation, the method of solving the drag coefficient of a two-dimensional airfoil is theoretically derived in detail. The drag coefficient integral equation is established and optimized by converting the integrated variable. On this basis, the accurate measurement test method and uncertainty analysis method for airfoil drag coefficient are established, which provides a theoretical basis and technical means for accurate measurement and uncertainty analysis of airfoil drag coefficient in high-speed wind tunnels.
Influence of microwave parameters on the xenon afterglow beam currents of a superconducting electron cyclotron resonance ion source
Authors: Li L. X. , Li J. B. , Ma J. D. , Feng Y. C. , Wang X. Y. , Fang X. , Lu W. , Tarvainen O. , Sun L. T. , Zhao H. W.
Published: February 2025

Heavy ion synchrotron accelerators rely on intense pulsed beams of highly charged ions. The production of these pulsed beams from an electron cyclotron resonance (ECR) ion source is predominantly achieved through the afterglow mode. However, the influence of microwave parameters on the characteristics of afterglow beams in high-frequency, high-power, and large plasma-volume ion sources remains unexplored. Recently, a series of experiments have been conducted with a third-generation superconducting ECR ion source. The effects of key microwave parameters, including the power level and pulse length of the secondary microwave source, as well as the RF-off time of the primary microwave radiation, on xenon afterglow beam currents are systematically examined. The experimental results and conclusions derived from the data are presented in this article.
Non-Fourier electrothermal fully coupled analysis of a 5 nm gate-all-around field-effect transistor based on density gradient theory
Authors: Liu Zhe , Sun Bo Hua , Cui Hai Hang , Sun Kai
Published: February 2025

In the post-Moore era, the three-dimensional fully surrounded channel structure of gate-all-around field-effect transistors (GAAFETs) significantly enhances gate control capabilities. However, its nanoscale features lead to severe overall self-heating effects and thermal spatiotemporal non-uniformity issues. In light of this, we investigated the electrothermal coupling characteristics of a 5 nm GAAFET device numerically. First, a three-dimensional electrothermal coupling simulation framework suitable for nanoscale transistors is established based on the density gradient (DG) model and the phonon hydrodynamic model and solved by the finite element method. Here, the DG model, combined with barrier boundary conditions, is employed to describe the spatial variation of charge carrier density and the quantum confinement effects at the oxide–semiconductor interface. The phonon hydrodynamic equations, along with temperature jump boundary conditions that account for interface phonon scattering, are utilized to characterize the unsteady processes of non-Fourier phonon heat transport. The governing equations for the electric and thermal fields are coupled bidirectionally. The results indicate that the developed electrothermal coupling analysis method under the continuous medium framework takes into account the quantum confinement effects of electrons at the oxide/semiconductor interface, as well as the phonon scattering effects at the interface. It can accurately predict the electrical and thermal processes of GAAFET devices. In contrast, the traditional drift-diffusion model tends to overestimate the predicted current, leading to an overestimation of temperature predictions. This work can be reasonably extended to predict and evaluate the electrothermal performance of other semiconductor devices, thereby providing theoretical support for the reliability design and optimization of novel semiconductor devices.
Touching the classical scaling in penetrative convection
Authors: Ouyang Zhen , Wang Qi , Li Kai , Wen Baole , Ding Zijing
Published: February 2025

The Cassini missions have identified the tiger stripes on Enceladus as the source of both thermal emission and plume jets. The hot spots in the tiger stripes are highly localized, and the plumes suggest active hydrothermal processes within the subglacial ocean of Enceladus. However, understanding the mechanism responsible for the heat anomalies in the tiger stripes remains a challenge. About 60 y ago, geoscientist George Veronis proposed a model for cold water oceans, along with the classical notion of a 1/3 scaling relationship between vertical heat transfer and the Rayleigh number (
Ra
), a dimensionless number representing the strength of buoyancy driving the convection within the fluid body. In this study, by delving into the steady coherent rolls arising in Veronis’ model, we first confirm the existence of the classical scaling as proposed. We identify two distinct pathways, characterized by different flow patterns, that converge to the unified classical scaling. In scenarios where stratification resulting from the density’s nonlinear temperature dependence is insignificant, convection rolls with fixed (width-to-height) aspect ratios achieve the classical scaling as
Ra
approaches infinity. Conversely, under high stratification levels, convection rolls with a heat-transport-maximizing aspect ratio achieve the classical scaling. This investigation also reveals a notable correspondence between optimal coherent rolls and turbulent flow patterns. Based on these coherent rolls, we offer insights into the formation of heat anomalies in the tiger stripes. The predicted heat flux through the ocean and the lateral flow length, are consistent with the measurements obtained by the Cassini spacecraft.
Thermal-solutal-induced bistability of evaporating multicomponent liquid thin films
Authors: Wakata Yuki , Wang Feng , Sun Chao , Lohse Detlef
Published: February 2025

Volatile multicomponent liquid films show rich dynamics, due to the complex interplay of gradients in temperature and in solute concentrations. Here, we study the evaporation dynamics of a tricomponent liquid film, consisting of water, ethanol, and trans-anethole oil (known as “ouzo”). With the preferential evaporation of ethanol, cellular convective structures are observed both in the thermal patterns and in the nucleated oil droplet patterns. However, the feature sizes of these two patterns can differ, indicating dual instability mechanisms dominated by either temperature or solute concentration. Using numerical simulations, we quantitatively compare the contributions of temperature and solute concentration on the surface tension. Our results reveal that the thermal Marangoni effect predominates at the initial evaporation stage, resulting in cellular patterns in thermal images, while the solutal Marangoni effect gradually becomes dominant. By regulating the transition time of this thermal-solutal-induced bistability and the nucleation time of oil microdroplets in the ternary mixture, the oil droplet patterns can be well controlled. This capability not only enhances our understanding of the evaporation dynamics but also paves the way for precise manipulation of nucleation and deposition processes at larger scales.
Aqueous power source integrated on a microfluidic chip
Authors: Yeon Song Yi , Kim Yunju , Kang Chung Mu , Park Sanguk , Chung Taek Dong
Published: February 2025

The growing demand for portable sensors for point-of-care (POC) and onsite health monitoring has led to significant interest in developing suitable power sources. In this study, we developed a microfluidic chip-integrated reverse electrodialysis (μRED) system for ecofriendly power generation with monolithic operation. Leveraging its fully ionic characteristic, μRED was successfully applied to an ionic diode, thereby demonstrating its capability for seamless integration. The feasibility of operating a bipolar electrode sensor without an external power supply was demonstrated, highlighting its broad applicability in electrochemical portable sensors. μRED has great potential for future applications, including electrochemical sensors for POC diagnostics and wearable devices.
Mixed methods research in L2 pragmatics
Authors: Youn Soo Jung
Published: February 2025

In this article, I discuss current research issues and practices in second language (L2) pragmatics research, focusing on how mixed methods are applied in the existing literature. The paper begins by introducing fundamental principles and three core mixed methods approaches, in each case synthesizing unique characteristics in terms of the integration of qualitative and quantitative methods and data interpretation. A critical review of different mixed methods approaches intends to help readers understand the strengths and weaknesses of each approach and make a principled decision. I then provide an overview of the recent trend in applying mixed methods in L2 pragmatics research, examining research purposes and the type of mixed methods designs utilized. I also offer an in-depth discussion of exemplary L2 pragmatics research that employed mixed methods focusing on underlying rationales for using the mixed methods and ways to achieve high degrees of integration at various stages of the study. The paper concludes with challenges in applying mixed methods and suggestions on how to advance the current practice of mixed methods in L2 pragmatics in future research.
“Why we are voting Biden-Harris”
Authors: Cabrejas-Peñuelas Ana Belén
Published: February 2025

The present study explores how text-image cohesion is achieved in a dataset of thirty-seven political ads in the
playlist “Why we are voting Biden-Harris,” which is part of the 2020 Biden for President Campaign. A further objective is to
analyze how multimodal cohesion contributes to persuasion in political campaign ads. Using methods from Systemic Functional
Linguistics (Halliday and Hasan 1976) and multimodal views of cohesion (Tseng 2013; Bateman 2014), both quantitative
and qualitative results are obtained. The quantitative results reveal that most cohesive types are of the lexical type, followed
by referential, conjunction, ellipsis, and substitution. Also, the visual and verbal chains outnumber the audio chains and, thus,
they are responsible for cohesion in the ads. The qualitative results show that multimodal cohesion is a powerful tool for
supporting persuasion in political campaigns by appealing to emotions, a hypothetical future, rationality, voices of expertise,
and altruism (Reyes 2011).
The status and unique characteristics of wetlands
Authors: Geze Wudu , Desta Takele Taye
Published: February 2025

Wetlands take various forms; accordingly, they may include artificial or natural water, permanent or temporary water, fresh, brackish, or salt water that is static or flowing, including seawater that is not deeper than 6 meters at low tide. We reviewed the status and unique attributes of wetlands. Wetland characteristics can differ spatially and temporally depending on climatical and topographical conditions. Wetlands are categorized based on species richness, water depth (deep or shallow), precipitation, pH, the concentration of dissolved oxygen, temporal and spatial variation, size (small, medium, or large), location, slope, and substrate composition. In developing countries like Ethiopia, the status of wetlands is poorly documented. Nevertheless, wetlands deliver various ecological and socio-economic services. There are three levels of lakes and wetlands in the global lakes and wetlands database. Level 1 (GLWD-1) wetland includes 3067 largest lakes with an area of ≥ 50 km
2
and 654 largest reservoirs with a storage capacity of ≥ 0.5 km
3
. Level 2 (GLWD-2) consists of permanent open water bodies having a surface area of at least 0.1 km
2
. Level 3 (GLWD-3) includes lakes, reservoirs, rivers, and various forms of wetlands. The public relies on wetlands, yet no attempts have been made to conserve or acknowledge their use values. Wetlands have degraded locally and globally because they have been converted to various land use types. For example, since the 1700s, almost 87% of the world’s wetlands have disappeared. Both natural and man-made factors contribute to the startling rate of wetland loss. Wetland loss and degradation result in the loss of biodiversity and ecosystem services they are providing. Thus, wetland preservation must be in the lead when dealing with ecosystem restoration.
Zinc ferrite nanoparticles as electrode material for supercapacitors
Authors: Pradhan Kousik , Singh Umisha , Shukla Shobha , Duttagupta Siddhartha P , Saxena Sumit
Published: February 2025

In the realm of sustainable and renewable nanotechnology, supercapacitors have appeared as the dominant solution for energy conversion and storage. Ferrites while being widely explored in magnetic, electronic and microwave devices, are now being explored for applications in energy storage devices due to possibilities of achieving fast and reversible surface Faradic reactions. In this perspective, a simple and inexpensive chemical co-precipitation method was used to synthesize ultra small ZnFe2O4 nanoparticles (NP). The ZnFe2O4 NP as electrode material show gravimetric capacitance of 186.6 Fg−1 at current density of 1 Ag−1 in 1M H2SO4. Furthermore, the ZnFe2O4 NP based electrode show exceptional capacitive retention of 98% over 1000 cycles at a current density of 3 Ag−1. An asymmetric ZnFe2O4 NP//NiO NP device was fabricated, which achieved a power density of 302.3 WKg−1 at current density of 1.5 Ag−1 and energy density of 14.85 WhKg−1. After 1500 cycles, the device demonstrated capacity retention of 99.4% at 1.5 Ag−1 in the long-term stability testing with 100% efficiency. Our study suggests that ZnFe2O4 NP are promising as a material for future energy storage applications.
Alternated two-particle discrete-time quantum walk on arbitrary graphs and its application on graph isomorphism testing
Authors: Li Panlong , Li Dan , Zhou Yuqian , Duan Bojia , Yang Yuguang
Published: February 2025

This paper introduces a novel alternated two-particle discrete-time quantum walk model on arbitrary graphs, overcoming the limitation that conventional shared coin schemes are confined to regular graphs. By employing a fixed-dimension coin operator and encoding the graph structural information into the shift operator, the new model becomes applicable to arbitrary graphs. Further, by adding interaction between the two particles, an extension is presented, which can enhance the model’s dynamic properties and facilitate more intricate quantum interference phenomena. Based on the new model, a kind of quantum graph isomorphism algorithm framework is proposed. It just need O(N
0.5*∣E∣) steps of quantum walk and O(N
2) dimensions of Hilbert space, which offers a significant reduction in complexity compared to other quantum walk based algorithms. The graph isomorphism testing is performed in the framework using non-interacting and interacting quantum walks respectively. Experimental results illustrate that the algorithm based on interacting particles achieves a 100% success rate in discriminating all test graphs. While the algorithm with non-interacting particles performs a 100% distinction success rate on general non-regular graphs, albeit being ineffective on strongly regular graphs. Due to the effectiveness of the algorithm on arbitrary graphs, the algorithm has broad application prospects in the identification and comparison of chemical molecular structures, the analysis of social networks and so on.
Hybrid Artificial Neural Network-Particle Swarm Optimization approach to investigate the Blood Flow through an Artery affected by Aneurysm
Authors: Chand Madhusmita , Tripathi Rajat
Published: February 2025

Weakening of the arterial wall leads to the formation of a sac-like structure called an aneurysm. Shear stress at the arterial walls can contribute to bulge initiation, growth, expansive arterial remodelling, and an increased risk of bulge rupture. This study aims to explore the variations in wall shear stress (WSS) and entropy generation in the context of irreversible blood flow through an artery affected by an aneurysm under magnetohydrodynamic conditions utilizing machine learning techniques. The Casson fluid model is employed to depict the non-Newtonian behaviour of blood. A model describing the above-considered blood flow problem with mild aneurysms is developed, and the obtained partial differential equations, along with the suitable conditions, have been numerically treated using an explicit finite difference scheme. In this study, it has been observed that an intensified heart pulse frequency results in lower wall shear stress on the aneurysm-affected arterial wall, while the wall shear stress is significantly reduced on the outer layer of the arterial wall affected by an aneurysm. Entropy generation and WSS are optimized using a machine learning approach, employing the Particle Swarm Optimization (PSO) algorithm along with an Artificial Neural Network (ANN). The network is trained using the Levenberg–Marquardt training procedure. Through the application of this machine learning approach, specific values for the Hartmann number, dimensionless temperature difference, heart pulse frequency, and amplitude of the pulsatile component of pressure gradient have been identified to achieve the minimum entropy generation.
First direction sensitive search for dark matter with a nuclear emulsion detector at a surface site
Authors: Umemoto A. , Naka T. , Shiraishi T. , Sato O. , Asada T. , De Lellis G. , Kobayashi R. , Alexandrov A. , Tioukov V. , D'Ambrosio N. , Rosa G.
Published: February 2025

Fine-grained nuclear emulsion films have been developed as a tracking detector with nanometric spatial resolution to be used in direction-sensitive dark matter searches, thanks to novel readout technologies capable of exploiting this unprecedented resolution. Emulsion detectors are time insensitive. Therefore, a directional dark matter search with such detector requires the use of an equatorial telescope to absorb the Earth rotation effect. We have conducted for the first time a directional dark matter search in an unshielded location, at the sea level, by keeping an emulsion detector exposed for 39 days on an equatorial telescope mount. The observed angular distribution of the data collected during an exposure equivalent to 0.59 g days agrees with the background model and an exclusion plot was then derived in the dark matter mass and cross-section plane: cross-sections higher than 9.2 × 10-29 cm2 and 1.2 × 10-31 cm2 were excluded for a dark matter mass of 10 GeV/c
2 and 100 GeV/c
2, respectively.
This is the first direction sensitive search for dark matter with a solid-state, particle tracking detector.
Experimental study on the damage characteristics of sol-gel antireflection coatings on large-aperture optical components by in-situ plasma cleaning
Authors: Shen Rongqi , Li Yuhai , Wang Zixu , Sun Laixi , Yuan Xiaodong , Dong Xiang , Xiang Xia , Li Bo , Liu Xujie , Xu Xueshi , Wang Tingting , Bai Qingshun
Published: February 2025

Low-pressure plasma cleaning technology is currently regarded as a highly promising method for the effective in-situ removal of surface contaminants from large-aperture optical components (LAOC) (⩾430 mm) in laser fusion facilities. After a long cleaning, irreversible damage can occur to the sol-gel antireflective (AR) coatings on the surface of the LAOCs. Hence, a study was conducted to analyze the surface damage characteristics of low-pressure plasma cleaning on optical components and implement in-situ plasma cleaning techniques in the laser fusion facility. Initially, the impact of organic contaminant levels on the performance of optical components was assessed by experiments. Subsequently, the correlation between plasma cleaning duration, transmittance, wavelength peak, and laser-induced damage threshold of sol-gel antireflection coating on the LAOCs was examined. Experimental findings from plasma cleaning trials revealed that prolonged plasma exposure had a cumulative detrimental influence on coating thickness and optical performance, gradually increasing surface pores. Ultimately, investigating the surface damage mechanism of sol-gel AR coatings during low-pressure plasma cleaning establishes a groundwork for achieving non-destructive in-situ cleaning of LAOCs in laser fusion facilities.
Analysis of the Cryogenic Structure of the Concentric HTS Cable Joint
Authors: Hu Liguang , Cheng Jian , Chen Tengbiao , Chen Cheng , Cheng Qi , Chen Chunlong , Wang Bangzhu
Published: February 2025

Due to merits of low loss, large capacity and compactness, concentric high-temperature superconducting (HTS) cable has become an ideal solution for the large-capacity power transmission in a narrow path. As the three phases in the concentric HTS cable are wounded one by one in the same former, the non-superconducting joints are concentrated in a short range. The same cooling method as the normal section will cause the local temperature to rise and subject to hot spot risks. This paper conducts a study on the cryogenic cooling structure design of the joint of the concentric HTS cable. The heat generation mechanism is analysed. Based on the heat transfer enhancement method and computational fluid dynamic (CFD) simulation, the optimal cryogenic structure is proposed. The results are of significance to the safe and stable operation of the joint in the engineering application of the concentric HTS power transmission.
Study on the Preparation Process Optimization and Adsorption Characteristics of Metallic Oxide Composite Modified Quartz Sand
Authors: Li Guohao
Published: February 2025

The conventional water treatment process is difficult to remove micropollutants. Meanwhile, filtration is the last barrier to this process. One of the important factors of the influence of effluent quality is adsorption and interception on the surface of the filter. The metallic oxide composite modified quartz sand (MCMS) is prepared with raw quartz sands (RQS) as the surface modification material, FeCl3, AlCl3, and ethanol solution of TiCl4 as the modifiers. Test results are as follows: (1) The preparation method is obtained. (2) The optimum preparation conditions are obtained by the method of SEM and EDS detection. (3) The surface characteristic of MCMS had been observed as a little ball shape. The composition of the surface metallic oxide is analyzed which consists of Fe2O3, TiO2, Al2O3, SiO2, and FeO(OH) or AlO(OH). (4) The specific surface area of MCMS is 39.10 times as RQS and 3.38 times as IOCS. The combination of metallic oxide which produces a large number of hydroxyl isα-Fe2O3, AlO(OH), and Anatase TiO2 by the detection of phase identification from XRD. Organic matter removal of MCMS is 1.5 times as IOCS. (5) The average of HA removal of MCMS can reach to 91.56%. The adsorption characteristics of MCMS are both physical adsorption and chemical adsorption, meanwhile being based on chemical adsorption.
Progress in Separation Technology for Retired Photovoltaic Modules and Suggestions for Recycling
Authors: Li Yanfeng , Liu Zilin , Lin Dehai , Zhang Enfu , Liu Zhan , Dong Yang , Sheng Xiaoming , Li Zihan , Li Li , He Faquan
Published: February 2025

With the “double carbon” target and energy structure upgrading, the PV industry in China is increasing rapidly, and retired PV modules are becoming one of the key limiting factors for the green development of new energy. The recycling of PV modules is becoming more and more important, and module separation is the focus of research at home and abroad. Based on the investigation of domestic and foreign literature, the principle, research progress, and development potential of separation technology by mechanical method, pyrolysis method, and chemical method are analyzed, which provides reference and suggestion for the development of PV module recycling from the direction of green cycle.
Simulation Study on the Operational Performance of Continuous Mixers Based on the Discrete Element Method (DEM)
Authors: Xiao Yaomeng , Zhang Zhaoyun , Gao Zhongxiang , Zhang Daixiang , Ma Guanguo
Published: February 2025

This study aims to systematically analyze the effects of various operational parameters on the continuous mixing process of concrete using the Discrete Element Method (DEM) combined with a wet mixing model, with the objective of optimizing mixing uniformity and material flow to improve concrete mixing quality and efficiency in practical engineering applications. The results indicate that an appropriate water addition rate (e.g., 10 m/s) and a moderate moisture content (e.g., 2:9) can significantly enhance the uniformity of concrete mixing. Additionally, a moderate rotational speed (e.g., 200 rpm) achieved good mixing effects in a short time, avoiding issues such as oversaturation and uneven mixing. This study provides theoretical support and a data foundation for optimizing concrete mixing processes, contributing to improvements in mixing quality and efficiency in engineering practice.
Optimization on the Preparation Conditions of Fe-N/BC Catalyst and its Pollution Removal Efficiency
Authors: Zhou Ting , Yang Yang , Du Tianxing , Dong Wenyi , Wang Hongjie
Published: February 2025

This study was aimed to optimize the preparation conditions of Fe-N/BC catalyst. Citric acid iron and melamine was used to co-doped modified selected biomass, optimized factors included biomass type, acid washing time, iron-nitrogen doping amount and pyrolysis temperature, with nitrobenzene as the targeted degradation object. The optimal preparation conditions for Fe-N/BC iron-nitrogen co-doped biochar catalyst were determined. The results showed that using onion as the biomass, after 8 hours of acid washing, immersed in an ultrasonic solution of citric acid iron with a concentration of 8 g/L for 30 minutes, followed by adding melamine at a doping ratio of 5 g/g biomass and another 30 minutes of ultrasonication, centrifuged, water washed, and dried, then pyrolyzed at 900°C under N2 atmosphere for 1 hour. The obtained Fe-N/BC iron-nitrogen co-doped biochar catalyst exhibited the best removal efficiency for nitrobenzene in a catalytic reduction system, with a removal rate of 96.6% after 15 minutes of reaction.
Analysis of the Causes of Stripe Black Spot Defects in Hot-Dip Galvanized Strip of Thin Slab Continuous Casting and Rolling Production Line
Authors: Wang Jiangong
Published: February 2025

After the thin slab continuous casting and rolling production line of a domestic steel plant was put into operation, with the vigorous development of hot-dip galvanized products, the strip blackening defect on the surface became more prominent. After hot-dip galvanizing, the coil had a certain spacing of strip black spot defects on the surface, which could not meet the needs of high-end users and restricted the improvement of the manufacturing capacity of the headless production line.Therefore, this article uses scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), three-dimensional profilometer, and optical microscope (OM) to study the microscopic characteristics and causes of black spot defects on the surface of hot-dip galvanized steel. There are a large number of oxidized black spots on the surface of the stripe black area. The zinc layer thickness of the cross-section at the blackened area is smaller than that of the normal area, and the secondary dendrites inside the zinc layer at the blackened area are not well-developed in the normal area. The surface roughness Ra and Rt of the blackened position in the three-dimensional morphology display show significant differences from the normal position. Electron microscopy observation shows that the grain size of the substrate at the blackened area is different from that at the normal area after removing the zinc layer, which is the direct cause of the final surface showing stripe black spot defects. By optimizing the heating temperature uniformity of the IH on the thin slab continuous casting and rolling production line, the stripe black spot defects were ultimately eliminated.
Finite Element Analysis of the Mechanism of Transverse Crack Formation in 15CrMoG Water-cooled Walls
Authors: Li Ye , Pei Yang , Zhao Yue
Published: February 2025

In recent years, during the maintenance of 660MW ultra-supercritical boiler water walls, it has been discovered that large-scale surface transverse cracks have developed on the fire-facing tubes within specific regions, posing considerable safety hazards to the boiler’s operation. This paper conducts mathematical modeling of a water wall panel and specific tubes in a unit, simulating the following scenarios: the influence of the soot-blowing process on the stress distribution within the water wall; the stress response when significant temperature gradients exist within a specific panel; and the extent of stress peak changes when abnormal heat exchange occurs due to local blockage or coking of the water wall. The results indicate that while the soot-blowing process affects the stress distribution, the maximum stress values in the tube wall change relatively little. However, when abnormal heat transfer occurs in the tubes, the thermal stress peaks increase sharply, significantly impacting the formation of transverse cracks in the tube wall and potentially even causing short-term overheating and bursting of the tubes.
The Application of SEM Test Technology in Full-graded Concrete’s Long Age Alkali Reactivity Test Research in A Hydropower Station
Authors: Shao Xiaomei , Zhang Liang , Zhou Lu
Published: February 2025

This paper is based on the study of the sandstone aggregate alkali reactivity in a large hydropower station in China, with full consideration to the engineering practice creatively carries out the long age simulation experiment of full-graded and mass volume concrete Alkali aggregate’s reaction, using SEM test technology and combining with existing alkali aggregate reaction assessment system, studies aggregate alkali activity inhibition effect of long-term effectiveness. The results of the study include that using the SEM test technology in the long aged tests of full-graded concrete alkali aggregate reaction in a hydropower station can obviously observe the characteristics of reaction products that react in the active alkali-aggregate reaction aggregate interface, learn about its active alkali-aggregate reaction in semi-quantitative degree, and predict trends of concrete deterioration.
Finite Element Method-Based Safety Assessment of a Gas Pipeline with Bulge Defect
Authors: Xiang Zhi , Tang Xiatao , Liu Quanbing , Chen Yin , Wang Zhongyan , Li Jintao
Published: February 2025

A safety assessment was conducted on a natural gas pipeline tee section containing a bulge defect. Geometric data of the bulge were sampled to establish a finite element model of the defective pipe section for stress analysis, which was compared to a defect-free model. The load-bearing capacity of the defective section was predicted using conventional design and analytical design methods, respectively. The results showed that under the design pressure, the maximum stress in the defective section was 71% of the allowable stress, indicating a safe stress level. The bulge did not increase local stresses, suggesting a limited impact on the load-bearing capacity. The defective section could withstand pressures exceeding the design pressure, with the analytical design method yielding a significantly higher predicted value.
Preparation of nano-TiO2 by Biological Template Method and Its Visible Light Catalytic Performance
Authors: Cao Jiayi , Yang Yihong , Li Wanpeng , Zhan Zhixing , Liu Yuyi , Li Li , Peng Fuchang
Published: February 2025

Using tetrabutyl titanate as the titanium raw material and kapok flower core as the biological template, KBT-TiO2 samples with special morphology were prepared by a simple sol-gel process. The KBT-TiO2 samples were characterized by X-ray diffraction, scanning electron microscopy, UV-Vis and other techniques. Taking the photocatalytic degradation of methylene blue (MB) as a probe reaction, the visible light catalytic performance of different TiO2 samples was studied. The influence of calcination temperature and sample dosage on the photocatalytic performance of TiO2 were explored. The results showed that compared with the samples (pure-TiO2) synthesized by the non-template method, KBT-TiO2 samples retained and inherited the biological relic structure of the kapok flower core. Due to special morphology, the dispersion of KBT-TiO2 is improving, and its specific surface area is increased, it is beneficial to improving the visible light catalytic performance of the samples. As the calcination temperature increases, the catalytic performance of the sample first increases and then decreases. When the calcination temperature is 550°C, the calcination time is 3 hours, the initial concentration of MB is 10 mg·L−1 the sample input is 0.2 g, the photocatalytic performance of KBT-TiO2 samples reaches a maximum of 98.6%. The apparent first-order kinetic constant of the photocatalytic degradation of MB of KBT-TiO2 is 1.8 times that of pure-TiO2.
Localized Corrosion Behavior of T2 Copper and H62 Brass in NaCl Solution for Semiconductor Applications: An Electrochemical Study Using Wire Beam Electrode
Authors: Pan Chengqun , Zhang Tingxuan , Xing Yidan , Chen Chuan , Zhu Shan
Published: February 2025

T2 copper and H62 brass are widely used in semiconductor applications, particularly in interconnects and packaging components of integrated circuits. With increasing demands for performance and reliability, the corrosion resistance of these materials, especially in saline environments, becomes critical. Localized corrosion can significantly reduce electrical conductivity, impacting the long-term reliability of semiconductor devices. This study investigates the localized corrosion behavior of T2 copper and H62 brass in a 3.5 wt.% NaCl solution using the wire beam electrode (WBE) technique. Electrochemical measurements, including potential, current density, and localized corrosion intensity (LP), were conducted over varying immersion times. Results show that T2 copper exhibits superior corrosion resistance and lower localized corrosion sensitivity compared to H62 brass, which shows more pronounced corrosion, particularly at the electrode edges. As immersion time increases, H62 brass exhibits higher potential differences and LP values. These findings highlight the impact of localized corrosion on the conductivity of copper alloys and underscore the importance of selecting materials with enhanced corrosion resistance for semiconductor applications.
Evaluation of River Ecosystem Service Function Value Based on Emergy Analysis
Authors: Han Zifen , Zhang Yunyun , Shu Chaojiang , Zhu Hongyi
Published: February 2025

Evaluating the value of river ecosystem services can provide a theoretical basis and data support for the ecological protection and development of related watersheds in the survey region. Taking Gansu Province as an example, combined with the characteristics of river ecosystem services in Gansu Province, its river ecosystem service functions are classified into 5 categories at the first level and 15 categories at the second level, and an energy value assessment model is established to assess the value of river ecosystem services in Gansu Province in the years of abundance, flatness, depletion and typical hydrological years. The results show that: the energy value of river ecosystem services in Gansu Province is 902.84×1021 sej, 846.91×1021 sej, and 797.35×1021 sej in abundant, flat, and dry water years respectively, and the annual energy value currency is 197.13×1010 rmb, 184.91×1010 rmb and 174.09×1010 rmb respectively, and the ordering is High flow year > Mean water year > Low flow year. Mean water year > Low flow year, indicating that river flow has a greater impact on the value of river ecosystem services; Fresh water supply, ecological security, ecological regulation service function energy value, and monetary value in each hydrological year accounted for a large proportion, indicating that the ecological service function of rivers in Gansu Province is mainly manifested in the above three aspects, and material production and cultural recreation accounted for a relatively small proportion.
Experimental Study on Coal Ash to Improve Southern Paddy Field
Authors: Liu Pinyi , Bai Ling , Wen Yangping
Published: February 2025

In order to investigate the effect of a small dosage of pulverized coal ash on the improvement of rice paddies in southern China, the rice paddies in the suburban county of Nanchang City were taken as the research object, and the control group was set up. The effects of two kinds of pulverized coal ash on rice growth yield and straw length under different particle sizes and dosages were observed. The results showed that pulverized coal ash could change the pH value of cultivated soil in a short time. When the same amount of granular ash was added (e.g. 1.94kg/m2), the yield increase rate of rice was small granular ash (47.5%) > medium granular ash (35%) > large granular ash (15%). The yield increase of brown ash residue was higher than that of black ash residue. The effect of ash and slag on straw length is similar to that of rice yield. The increase in rice yield from 0.49kg/m2 to 0.86kg/m2 was greater than that from 0.86kg/m2 to 1.94kg/m2. The results of SEM, IR, and XRD analysis showed that the soil surface porosity was improved by ash.