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Resolving β Relaxation and Enhancing Thermal Stability of the Medium-Entropy Metallic Glass Zr35Ti30Be27.5Fe7.5 Through Modulating Initial Cooling Temperature

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SSRN 2024年

作者： Shang, Xiong Qiao, Jichao Tu, Wenkang Wang, Xiaodong Zhang, Yanhui Feng, Shidong Li, Zijing Wang, Li-Min Center for Advanced Structural Materials State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066004 China Key Lab for Microstructural Material Physics of Hebei Province School of Science Yanshan University Qinhuangdao066004 China School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi’an710072 China State Key Laboratory of Metastable Materials Science and Technology Nano-Biotechnology Key Lab of Hebei Province Applying Chemistry Key Lab of Hebei Province Heavy Metal Deep-Remediation in Water and Resource Reuse Key Lab of Hebei Yanshan University Qinhuangdao066004 China Hebei Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures School of Civil Engineering and Mechanics Yanshan University Qinhuangdao066004 China

Most conventional metallic glasses often exhibit an excess wing rather than clear resolving the β relaxation, making it challenging to fully understand this kinetic phenomenon. In this study, we investigated β relaxation in Zr35Ti30Be27.5Fe7.5 metallic glasses by varying the initial cooling temperature while maintaining constant cooling rates. The study results demonstrate that increasing the initial cooling temperature effectively resolve the β relaxation, which in turn significantly influences the glass transition and crystallization temperatures, enhancing the thermal stability of the metallic glass. Stress relaxation studies indicate that glasses quenched from higher melt temperatures exhibit a lower non-exponential parameter βKWW, indicative of greater dynamic heterogeneity, along with a broader distribution of relaxation times in the as-quenched samples. This study suggests that higher initial cooling temperatures not only facilitate a clearer examination of β relaxation but also promote structural heterogeneity in metallic glasses, which is linked to the observed β relaxation and the improvement in thermal stability. © 2024, The Authors. All rights reserved.

关键词： Glass transition

U(Ⅵ) sorption by porous sodium zirconium phosphate pellets from aqueous solution

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Arabian Journal of Chemistry 2024年第11期17卷

作者： Wang, Cheng Gui, Bingtao Li, Tianjie Chang, Ruiyang Shu, Junxiang Deng, Xiaoqin Chen, Li Luo, Maodan Jiang, Bing Xu, Su Zhai, Juan Liu, Jun Zhao, Changsong College of Nuclear Technology and Automation Engineering Chengdu University of Technology Sichuan Chengdu610059 China School of Public Health Chengdu Medical College Sichuan Chengdu610500 China Sichuan Management and Monitoring Center Station of Radioactive Environment Sichuan Chengdu610059 China Applied Nuclear Technology in Geosciences Key Laboratory of Sichuan Province Chengdu University of Technology Sichuan Chengdu610059 China

Zirconium phosphate is the first artificially produced layered phosphate that can sorb a variety of nuclides from solutions. Sodium zirconium phosphate (NZP) was a type of α-zirconium phosphate (α-ZrP). The porous sodium zirconium phosphate pellets (p-NZP-P) with a diameter of more than ∼3 mm were prepared and used for uranium sorption. The p-NZP-P could be immersed in solutions for more than 5 days without dissolving and structurally collapsing. The sorption properties of U(Ⅵ) on p-NZP-P in solutions were investigated by both static and dynamic sorption tests. Synthetic p-NZP-P was analyzed in detail using various characterizations to investigate their character and structural changes. In the static sorption experiment, the equilibrium sorption capacity reached the 77.5 ± 1.5 mg·g−1 when the initial concentration of U(Ⅵ) was 100 mg/L, pHinitial = 4.5, T = 25 ℃. Uranium sorption increased by ∼69 % and ∼215 %, respectively, when the initial uranium concentration was increased from 100 to 300 mg·L−1 and the temperature was increased from 15 to 55 °C. Furthermore, uranium sorption increased by ∼541 % when the initial pH increased from 2.5 to 4.5, while it decreased by ∼39 % when the initial pH increased from 4.5 to 7.0. The sorption data corresponded to the pseudo-second-order kinetic model and the Langmuir isotherm model, as well as the theoretically predicted value of sorption capacity (∼199.9 mg·g−1). The results of the dynamic sorption experiment showed that decreasing the quality, increasing the flow rate and the initial U(Ⅵ) concentration would shorten the breakthrough time. The dynamic sorption data agreed well with the Thomas model. The characterization confirmed the porous properties, while the U(Ⅵ) sorption mechanisms relate to –OH coordination and ion exchange. A radioactive rare earth wastewater treatment test suggested that p-NZP-P could be the potential uranium sorbent due to its good stability and efficiency. This paper opened opportunities for the devel

关键词： Ion exchange

Recycling Waste Iron-Rich Algal Flocs as Cost-Effective Biochar Activator for Heterogeneous Fenton-Like Reaction Towards Tetracycline Degradation: Important Role of Iron Species and Moderately Defective Structures

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SSRN 2023年

作者： Xia, Wei Lia, Sha Wu, Genyu Ma, Jiangya School of Civil Engineering and Architecture Anhui University of Technology Anhui Maanshan243002 China State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing210023 China Anhui University of Technology China

Harvesting aquatic harmful algal blooms (HABs) and reusing them is a promising way for antibiotic degradation. Herein, a novel iron-rich algal-based biochar (Fe-ABC), derived from algal flocs formed by magnetic coagulation, was successfully designed and fabricated as activator for heterogeneous Fenton-like reaction. The modification methods and pyrolysis temperatures (400 °C–800 °C) were optimized to enhance the formation of rich iron species and moderately defective structure, concluding that Fe-ABC-600 showed enhanced charge storage and electron transfer capability. Thus, Fe-ABC-600 exhibited superior removal efficiency (95.33%) on tetracycline (TC), where the presence of multiple iron species (Fe3+, Fe2+ and Fe4+) and moderately defective structure accelerating the Fenton-like oxidation catalyzed by Fe2+, and the heterogeneous Fenton-like system always maintained >0.2 mg/L of iron ions in five cycles, ensuring the sustained degradation. And OH was proved to be the major radical contributing to the degradation of TC, as well as the direct electron transfer mechanism together, in which the C=O acted as electron regulator and electron donor. Fe-ABC as a cost-effective catalyst has notable application potentials in TC removal from wastewater owing to its remarkable advantages of high resource utilization, enhanced catalytic property, high ecological safe, notable TC degradation efficiency, low cost and environmental-friendliness. © 2023, The Authors. All rights reserved.

关键词： Magnetic separation

The Quantitative Relationship between Adversarial Training and Robustness of CNN Model

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The Quantitative Relationship between Adversarial Training a...

International Conference on Dependable Systems and Their Applications (DSA)

作者： Jie Wang Minyan Lu Jun Ai Xueyuan Sun The Key Laboratory on Reliability and Environment Engineering Technology School of Reliability and Systems Engineering Beihang University Beijing China

ISBN: (数字)9780738124223

ISBN: (纸本)9781665419536

With the increasing application of deep neural networks in security-critical systems, robustness becomes an important property for deep learning. However, deep neural networks are very vulnerable to perturbations, especially adversarial attacks. The adversarial training by adding adversarial examples to the training set has become a common method to improve the performance of deep neural networks. In this paper, based on the existing robustness metrics and indicators, we study the quantitative influence of adversarial training on the robustness of network-in-network and residual network, and the differences of indicators are compared. The experimental results show that adversarial training can affect the accuracy and robustness of CNN models, and the variation trends of testing accuracy and robustness are opposite.

关键词： Training Perturbation methods Neural networks Market research Robustness Testing Residual neural networks

Preparation of Pmia Loose Nanofiltration Membrane with Electrostatic Layer-by-Layer Self-Assembled for Dye/Salt Filtration

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SSRN 2023年

作者： Du, Xiongfei Li, Yang Sun, Kaixuan Liu, Hailiang Shao, Lu Huang, Qinglin State Key Laboratory of Separation Membranes and Membrane Processes National Center for International Joint Research on Separation Membranes Tiangong University Tianjin300387 China Department of Material Science and Engineering Tiangong University Tianjin300387 China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin150001 China

In this study, loose PMIA nanofiltration membranes were fabricated by electrospinning method and electrostatic layer by-layer (LBL) self-assembly technique, which the polyelectrolyte multilayers (PEMs) generated by polyacrylic acid (PAA) and polyethyleneimine (PEI) were used to regulate the nanofiber membrane surface functional layer. Effects of spraying time and nano-SiO2 content on the morphology, chemical structure and dyes separation efficiency of PEMs functional layer were investigated, respectively. The results showed that the construction of the PEMs functional layer could obviously enhance the Congo red (CR) filtration efficiency by increasing the rejection from 4.9% to 99.8% and improve the surface hydrophilicity by reducing the water contact angle (WCA) from 90.1° to 51.8°. The prepared PEMs/PMIA/SiO2 membrane achieved a relatively stable permeation flux (22.9 L·m-2·h-1), while maintained high separation efficiency of CR/NaCl solution, revealing the excellent dye desalination performance, which exhibited a potential for the dye/salt wastewater treatment. In particular, we offered a new method to prepare loose nanofiltration (LNF) membranes by electrospinning and electrostatic self-assembly technique with accurate separation of inorganic salts and dye molecules © 2023, The Authors. All rights reserved.

关键词： Self assembly

Numerical study on stall characteristics of a triangular airfoil in low Reynolds number compressible flow

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Numerical study on stall characteristics of a triangular air...

17th Asian Congress of Fluid Mechanics (ACFM 2023)

作者： J. Wang C. Wang C. Liu J. Wu School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 People's Republic of China National Key Laboratory of space Environment and Matter Behaviors Harbin Institute of Technology Harbin 150001 People's Republic of China

Due to the low density and low temperature of the atmosphere on the surface of Mars, Mars aircraft are usually in compressible flow at low Reynolds number. In this paper, the dynamic stall characteristics of triangular airfoil with reduced frequencies of 0.09 and 0.15 are studied based on large eddy simulation (LES). The incoming Mach number is 0.5 and the Reynolds number is 3000. The results show that, with the increase of reduced frequency, the lift and drag coefficient in dynamic motion gradually deviates from the static lift and drag coefficient, but the dynamic stall angle of attack has little difference with the static stall angle of attack. In order to obtain the main flow structure during blade dynamic stall, dynamic mode decomposition (DMD) was used to decompose and reconstruct the velocity vector field around the blade. The results show that the DMD decomposition modes mainly include time-average flow field with separation flow at the blade tail, low-frequency large-scale separation flow at the blade leading edge and tail enrolling effect, and high-frequency separation and attachment flow at the blade apex downstream. The first 20 modes reconstruction can basically restore the main flow structure of the flow field.

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Research on Artificial Bee Colony Method Based Complete Coverage Path Planning Algorithm for Search and Rescue Robot 5

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Research on Artificial Bee Colony Method Based Complete Cove...

5th International Symposium on Autonomous Systems, ISAS 2022

作者： Yang, Liu Xing, Bowen Li, Cai Wang, Wugui Shanghai Ocean University College of Engineering Science and Technology Shanghai201306 China South China Sea Oceanographic Research Institute Chinese Academy of Sciences National Key Laboratory for Tropical Marine Environment Guangzhou510308 China China Ship Development and Design Center Wuhan430064 China

ISBN: (纸本)9781665487085

In terms of the low efficiency of search and rescue robot's complete coverage path planning in the complex working environment, based on the traditional neural network optimization strategy, a complete coverage path planning strategy based on Artificial Bee Colony algorithm is proposed. Using the data collected by lidar or other sensors to build an environmental map model, with search and rescue robot as the main body, a neural network forward propagation model combined with an artificial bee colony algorithm was established, and the artificial bee colony method was used to optimize the parameters of the neural network by unsupervised training. It has improved the operability and portability of search and rescue robot working in different environments. And on this basis, an evaluation equation for evaluating the effect of complete coverage path planning is proposed, so as to automatically evaluate the quality of the generated complete coverage path during training. The simulation results show that for the unknown environment, based on the improved path planning algorithm, it has higher efficiency when performing the complete coverage path planning mission of the search and rescue robot. © 2022 IEEE.

关键词： Motion planning

An Efficient Method for Separation of Coal/Gangue with Thermal Imaging Technique and Water Evaporation

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SSRN 2022年

作者： Li, Shanhu Zhang, Yanxin Tao, Yourui State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300401 China School of Mechanical Engineering Hebei University of Technology Tianjin300401 China School of Electrical Engineering Hebei University of Technology Tianjin300401 China

The identification of coal and gangue plays an important role in improving resource utilization and reducing environmental pollution. Due to the reason that the surface character of coal and gangue is closed to each other, it is difficult to obtain a satisfied recognition result in an efficient manner by using the traditional visible image analyzing method. Therefore, a thermal image recognition method with water intervention was proposed to efficiently distinguish coal from gangue with temperature difference. In this study, a method to improve the efficiency of coal and gangue recognition by using heat transfer effect to generate surface thermal image is proposed. Water is the principal heat transfer medium. According to the findings, when the water temperature is greater than the indoor temperature, the thermal images distinction of coal and gangue increases gradually with the medium temperature rose, and the thermal image with high contrast can be obtained with air flow intervention. Further comparative study revealed that coal and gangue can obtain the optimal contrast image when the water temperature is 55℃ for 15s with air motion intervention, which might be a novel way to increase the efficiency of coal and gangue identification in coal mines. © 2022, The Authors. All rights reserved.

关键词： Coal

The Fracture Toughness of Pbx, Part Ii：Establishment and Analysis of the Defect-Fracture Strength Model

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SSRN 2024年

作者： Wen, Chengji Sun, Jie Ma, Yuncan Wang, Lijun Yin, Ying Institute of Chemical Materials China Academy of Engineering Physics Mianyang621900 China State Key Laboratory of Environment-friendly Energy Material School of Materials Science and Engineering Southwest University of Science and Technology Mianyang621010 China Institute of Fluid Physics China Academy of Engineering Physics Mianyang621900 China

The defect fracture strength model is a physical model used to describe the response of material fracture strength to its defects, which is crucial for guiding material quality control and reliability prediction. In this Part II, we propose a modified linear elastic fracture strength model (LEFM) for polymer bonded explosive (PBX) by introducing inherent equivalent defect a*, achieving accurate description of the fracture strength of PBX containing various surface defects. The physical essence of a* is compared with other formally similar parameters, and it shows that a* is related to the micro-structure characteristics of PBX. The proposed modified LEFM unifies the strength criterion and fracture toughness criterion, and we experimentally validate the model on samples of different sizes to assess its applicability and analyze the transformation mechanism of fracture behavior caused by defect depth. © 2024, The Authors. All rights reserved.

关键词： Fracture toughness