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47 results on '"Xiong, Siwei"'

10. Towards Robust Stacked Capsule Autoencoder with Hybrid Adversarial Training

Author

Dai, Jiazhu and Xiong, Siwei

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence
Abstract

Capsule networks (CapsNets) are new neural networks that classify images based on the spatial relationships of features. By analyzing the pose of features and their relative positions, it is more capable to recognize images after affine transformation. The stacked capsule autoencoder (SCAE) is a state-of-the-art CapsNet, and achieved unsupervised classification of CapsNets for the first time. However, the security vulnerabilities and the robustness of the SCAE has rarely been explored. In this paper, we propose an evasion attack against SCAE, where the attacker can generate adversarial perturbations based on reducing the contribution of the object capsules in SCAE related to the original category of the image. The adversarial perturbations are then applied to the original images, and the perturbed images will be misclassified. Furthermore, we propose a defense method called Hybrid Adversarial Training (HAT) against such evasion attacks. HAT makes use of adversarial training and adversarial distillation to achieve better robustness and stability. We evaluate the defense method and the experimental results show that the refined SCAE model can achieve 82.14% classification accuracy under evasion attack. The source code is available at https://github.com/FrostbiteXSW/SCAE_Defense.

Published
2022

11. Preparation of high breakdown strength meta-aramid composite paper reinforced by polyphenylene sulfide superfine fiber

Author

Zhao, Yuzhen, Yao, Songjun, Xiong, Siwei, Li, Bingyang, Wang, Xuyi, Yang, Feihua, Jia, Yingbin, Wang, Luoxin, and Wang, Hua

Subjects
Polyphenylene sulphide -- Mechanical properties, Engineering and manufacturing industries, Science and technology, Mechanical properties
Abstract

Meta-aramid paper has been widely used in transformers because of its excellent insulation properties and thermal stability. However, with the rapid development of high-voltage transformers, higher requirements are placed on the breakdown strength of meta-aramid paper. In this study, meta-aramid chopped fibers/polyphenylene sulfide (MACFs/PPS) composite paper was prepared by a combination of wet-copying and hot-rolling technology. Then the microscopic morphology, mechanical properties, crystallization behavior, insulation properties, and thermal stability of the MACFs/PPS composite paper were studied and evaluated. The experimental results showed that the breakdown strength of the MACFs/PPS composite paper was as high as 46.46 kV/ mm, which was 2.7 times higher than the famous Nomex T410 insulating paper. Meanwhile, the MACFs/PPS composite paper presented good mechanical properties and thermal stability. This paper provides a simple and versatile method for the preparation of meta-aramid composite paper with high breakdown strength. KEYWORDS breakdown strength, mechanical properties, meta-aramid paper, polyphenylene sulfide superfine fiber, 1 | INTRODUCTION Meta-aramid fibers are one kind of high-performance fibers, which have high specific strength, modulus, excellent thermal stability and insulating properties because of their highly oriented hydrogen bonds [...]

Published
2023
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15. Integration of microRNA and mRNA analyses depicts the potential roles of Momordica charantia saponin administration in insulin resistance of juvenile common carp (Cyprinus carpio) fed with a high-starch diet

Author

Fan, Ze, primary, Wang, Liansheng, additional, Li, Chenhui, additional, Wu, Di, additional, Li, Jinnan, additional, Zhang, Haitao, additional, Xiong, Siwei, additional, Miao, Linghong, additional, Ge, Xianping, additional, and Li, Zhengwei, additional

Published
2023
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16. An Evasion Attack against Stacked Capsule Autoencoder

Author

Dai, Jiazhu and Xiong, Siwei

Subjects
Computer Science - Machine Learning, Computer Science - Cryptography and Security
Abstract

Capsule network is a type of neural network that uses the spatial relationship between features to classify images. By capturing the poses and relative positions between features, its ability to recognize affine transformation is improved, and it surpasses traditional convolutional neural networks (CNNs) when handling translation, rotation and scaling. The Stacked Capsule Autoencoder (SCAE) is the state-of-the-art capsule network. The SCAE encodes an image as capsules, each of which contains poses of features and their correlations. The encoded contents are then input into the downstream classifier to predict the categories of the images. Existing research mainly focuses on the security of capsule networks with dynamic routing or EM routing, and little attention has been given to the security and robustness of the SCAE. In this paper, we propose an evasion attack against the SCAE. After a perturbation is generated based on the output of the object capsules in the model, it is added to an image to reduce the contribution of the object capsules related to the original category of the image so that the perturbed image will be misclassified. We evaluate the attack using an image classification experiment, and the experimental results indicate that the attack can achieve high success rates and stealthiness. It confirms that the SCAE has a security vulnerability whereby it is possible to craft adversarial samples without changing the original structure of the image to fool the classifiers. We hope that our work will make the community aware of the threat of this attack and raise the attention given to the SCAE's security.

Published
2020

28. Effects of ionic liquids as catalysts on liquid crystal aromatic polyester based on thin‐film polymerization technique.

Author

Wu, Zexi, Shi, Caijie, Peng, Tao, Cheng, Qiannan, Tang, Qingquan, Wang, Luoxin, Wang, Hua, and Xiong, Siwei

Subjects
POLYESTERS, LIQUID crystals, POLYMERIZATION, CATALYTIC polymerization, IONIC liquids, CATALYSIS, CATALYSTS
Abstract

Liquid crystal aromatic polyesters (LCAPs) have been used in wide applications, such as chip packaging and airship skin. The traditional polymerization of LCAP is catalyzed by inorganic salts, for example, sodium acetate. Herein, we reported three kinds of ionic liquids (ILs) as catalysts to promote LCAP polymerization for the first time. The effects of ILs on the polymerization behaviors are investigated by in situ observing the liquid crystal (LC) phase behaviors based on the thin‐film polymerization technique. The evolution of LC phase over time was detailly investigated by analyzing the emergence, fusion, and growth of LC phase. The temperature from 170 to 210°C and the catalyst concentration in range from 0 to 0.5 wt% are compared, showing that temperature at 210°C and catalyst concentration at 0.5 wt% are the best polymerization conditions for all ILs catalysts. In comparison with trimethylsulfonium iodide and piperidine acetate, 1‐ethyl‐3‐methylimidazolium acetate has the best catalytic effect for the polymerization of LCAP in all experimental conditions. The successful polymerization was confirmed by FT‐IR spectra, showing the increased intensity of vibration peak at 1735 cm−1 attributed to the generation of ester groups while the decreased intensities of vibration peaks at 1759 and 1370 cm−1. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Floret-like Fe-Nx nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer boosting oxygen electroreduction.

Author

Zheng, Yong, Li, Mingjin, Wang, Yongye, Huang, Niu, Liu, Wei, Chen, Shan, Ni, Xuepeng, Li, Kunming, Xiong, Siwei, Shen, Yi, Liu, Siliang, Zhou, Baolong, Khan, Niaz Ali, Ye, Liqun, Zhang, Chao, and Liu, Tianxi

Abstract

Fe-Nx nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe-Nx nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe-Nx nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e− transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc—air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm−2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Growth of AgBr/Ag3PO4 Heterojunction on Chitosan Fibers for Degrading Organic Pollutants

Author

Xiong Siwei, Luo-xin Wang, Xian-ze Yin, Liu Man, Pei Wang, Shao-hua Chen, Wang Hua, and Yan Yu

Subjects
Chitosan, chemistry.chemical_compound, Materials science, chemistry, Chemical engineering, Methyl orange, Water environment, Photocatalysis, Degradation (geology), Chelation, Heterojunction, General Medicine, Fiber
Abstract

Using Fiber as the based material for photocatalyst particles is favorable for their recovery, thereby avoiding the photocatalyst particles cause secondary pollution to water environment. In this work, the AgBr and Ag3PO4 photocatalyst particles were loaded onto the surface of chitosan fiber (CF) via chelation and in situ anion-exchange method. The photocatalytic results illustrated that the AgBr/Ag3PO4/CF composites displayed the best photocatalytic performance when the mass ratio of Ag3PO4 and AgBr onto the CF was approximately 1:0.15, their degradation rate can reach 98.1% for the methyl orange (MO) solution, this value far exceeded those of pure CF, AgBr/CF composites, and Ag3PO4/CF composites. Besides, the AgBr/Ag3PO4/CF composites also shown excellent durability, after the fifth cycle, they still maintained a decolorization rate of 86.4% for the MO solution, while the Ag3PO4/CF composites maintained a decolorization rate of only 70.7%. Based on these results, we consider that the AgBr/Ag3PO4/CF composites have high practical interest in environmental remediation.

Published
2020

41. A flexible and efficient electro-Fenton cathode film with aeration function based on polyphenylene sulfide ultra-fine fiber

Author

Xiong Siwei, Panlong Lin, Liu Man, Yan Yu, Lingquan Hu, Shaohua Chen, Hua Wang, and Luoxin Wang

Subjects
Materials science, Polymers and Plastics, Sulfide, General Chemical Engineering, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Biochemistry, law.invention, chemistry.chemical_compound, law, Materials Chemistry, Methyl orange, Environmental Chemistry, Porosity, 0105 earth and related environmental sciences, chemistry.chemical_classification, General Chemistry, Carbon black, 021001 nanoscience & nanotechnology, Cathode, chemistry, Chemical engineering, Aeration, 0210 nano-technology, Current density, Methylene blue
Abstract

A novel cathode film with aeration function was prepared using a polyphenylene sulfide (PPS) ultra-fine fiber and conductive carbon black (CB). The flexible and non-metallic PPS cathode film was applied in the electro-Fenton (e-Fenton) system in order to degrade the contaminants in wastewater. The effects of the current density, contaminant species, initial pH, and aeration rate on the degradation rate of contaminants were systematically studied. The results show that the optimized conditions include a pH of 3 and a current density of 16 A m−2. It was found that the generation of H2O2 could be greatly enhanced, and several contaminants (methyl orange (MO), methylene blue (MB), rhodamine-B (RhB), malachite green (MG), Orange II (OII), and heptanaphthenic acid (HNA) could be efficiently degraded when the PPS cathode film was used in the e-Fenton system. This robust function of the e-Fenton system results from the benefits of the large porosity, good adsorptivity, and more active sites of the fabricated PPS cathode film. Additionally, the aeration function of the PPS cathode film strongly increased the removal rate of the contaminants. The PPS cathode film can be of potential application in the e-Fenton system for cost-efficient degradation of organic contaminants.

Published
2019

42. The attractive efficiency contributed by the in-situ reactivation of ferrous oxalate in heterogeneous Fenton process

Author

Hua Wang, Xianze Yin, Lingquan Hu, Pei Wang, Shaohua Chen, Luoxin Wang, and Xiong Siwei

Subjects
inorganic chemicals, General Physics and Astronomy, 02 engineering and technology, Surfaces and Interfaces, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Oxalate, 0104 chemical sciences, Surfaces, Coatings and Films, Ferrous, Catalysis, chemistry.chemical_compound, chemistry, Chemical engineering, Scientific method, Degradation (geology), Hydroxyl radical, 0210 nano-technology, Methylene blue, Reusability
Abstract

In this study, ferrous oxalate (FeC2O4) used as an effective heterogeneous Fenton catalyst, was inexpensively synthesized by a chemical precipitation method. The attractive efficiency was investigated to demonstrate the underlying mechanism of in-situ reactivation. Based on the mechanism, the important issue of effective performance suggested that the reactivation of active sites enhanced the activation of hydroxyl radical( OH) for degradation. In addition, the catalytic performance for industrial application was studied by evaluating the degradation of methylene blue (MB). In the typical process, a degradation efficiency over 94% was observed at 10 min, and it was improved to over 95% at 3 min under irradiation with a xenon lamp. The catalyst has high operational stability and reusability properties in the process. Remarkably, self-activation of the catalyst was observed during the recycling processes.

Published
2019

43. Immobilization of Ag3PO4 nanoparticles on chitosan fiber for photocatalytic degradation of methyl orange

Author

Luoxin Wang, Hua Wang, Zhenghui Zhao, Liu Man, Shaohua Chen, Xianze Yin, Junbao Yan, and Xiong Siwei

Subjects
Materials science, Polymers and Plastics, Diffuse reflectance infrared fourier transform, Scanning electron microscope, Energy-dispersive X-ray spectroscopy, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Methyl orange, Photocatalysis, Fiber, Fourier transform infrared spectroscopy, 0210 nano-technology, Photodegradation, Nuclear chemistry
Abstract

Ag3PO4 and chitosan fiber (CF) composites were successfully fabricated using an in situ growth technique. The structure and properties of the obtained Ag3PO4/CF composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy, and UV–visible diffuse reflectance spectroscopy. SEM results suggested that the 50–500 nm Ag3PO4 particles grew on the CF surface into a spherical or dentate shape. Photocatalytic degradation of methyl orange (MO) solution was used as a typical reaction to evaluate the visible-light photocatalytic performance of the Ag3PO4/CF composites. The reaction results indicated that the Ag3PO4/CF composites-3 exhibited excellent photodegradation efficiency, with 93.8% removal of the MO solution. The effects of MO concentrations and cycling runs on the photocatalytic performance of the Ag3PO4/CF composites were evaluated as well.

Published
2018

44. Fabrication and application of poly (phenylene sulfide) ultrafine fiber

Author

Yan Yu, Jing Xu, Luoxin Wang, Hao Huang, Xianze Yin, Kun Nie, Shaohua Chen, Hua Wang, Xiong Siwei, and Liang Zhao

Subjects
Materials science, Polymers and Plastics, General Chemical Engineering, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Lithium-ion battery, 0104 chemical sciences, Phenylene, Materials Chemistry, Environmental Chemistry, Thermal stability, Fiber, Composite material, Melt spinning, 0210 nano-technology, Melt electrospinning, Spinning, Separator (electricity)
Abstract

Poly (phenylene sulfide) ultrafine fiber is one kind of high-performance fiber with high specific surface area, corrosion resistance, chemical and thermal stability, which can be widely applied in various domains. However, there are few reports about the review of PPS ultrafine fiber. To meet this demand, the paper provides an overall investigation about the fabrication process of PPS ultrafine fiber including sea-island melt spinning, melt electrospinning and melt-blown spinning as well as the application of PPS ultrafine fiber based materials like high temperature filter, lithium ion battery separator, high strength and high modulus composites, oil/water separation membrane, catalytic, adsorption, degradation membrane and so on.

Published
2020

45. Immobilization of Ag3PO4 nanoparticles on chitosan fiber for photocatalytic degradation of methyl orange.

Author

Xiong, Siwei, Liu, Man, Yan, Junbao, Zhao, Zhenghui, Yin, Xianze, Wang, Luoxin, Chen, Shaohua, and Wang, Hua

Subjects
NANOPARTICLES, CHITOSAN, PHOTOCATALYTIC oxidation, X-ray diffraction, FOURIER transform infrared spectroscopy, SCANNING electron microscopy
Abstract

Ag3PO4 and chitosan fiber (CF) composites were successfully fabricated using an in situ growth technique. The structure and properties of the obtained Ag3PO4/CF composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy, and UV-visible diffuse reflectance spectroscopy. SEM results suggested that the 50-500 nm Ag3PO4 particles grew on the CF surface into a spherical or dentate shape. Photocatalytic degradation of methyl orange (MO) solution was used as a typical reaction to evaluate the visible-light photocatalytic performance of the Ag3PO4/CF composites. The reaction results indicated that the Ag3PO4/CF composites-3 exhibited excellent photodegradation efficiency, with 93.8% removal of the MO solution. The effects of MO concentrations and cycling runs on the photocatalytic performance of the Ag3PO4/CF composites were evaluated as well. [ABSTRACT FROM AUTHOR]

Published
2018
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46. Multifunctional liquid-like magnetic nanofluids mediated coating with anticorrosion and self-healing performance.

Author

Sun, Xiang, Gu, Shilong, Wang, Luoxin, Wang, Hua, Xiong, Siwei, Yin, Xianze, and Yang, Shiwen

Subjects
*SELF-healing materials, *CORROSION & anti-corrosives, *IRON oxides, *METAL coating, *HYBRID materials, *NANOFLUIDS, *SURFACE coatings
Abstract

[Display omitted] The long-term protective efficacy of organic coatings against corrosion can be diminished by the presence of micropores/cracks and poor self-healing capabilities. To address these issues, Ti 3 C 2 MXene was subjected to liquefaction-like treatment to maintain a two-dimensional lamellar structure in water and polymer matrix for a long time, as well as improve the dispersion stability and loading capacity of MXene. The inorganic corrosion inhibitor ferroferric oxide (Fe 3 O 4) was then electrostatically loaded onto MXene nanofluids to obtain a hybrid material. Through hydrogen bonding, polyvinyl alcohol (PVA) molecular chains were bridged to the hybrid material, resulting in a self-healing anti-corrosion coating. The coating exhibited excellent corrosion protection, as well as self-healing properties attributed to the labyrinth effect and corrosion inhibition of MXene@Fe 3 O 4 hybrids. Notably, electrochemical testing demonstrated outstanding corrosion resistance of this coating on diverse substrate surfaces. In addition, the anti-corrosion coating will strongly coalesce on the surface of B-NdFeB under magnetic stimulation, realizing the localized corrosion protection of metal materials. The anti-corrosion coating can be quickly repaired under the stimulation of water as well as recovery, the anti-corrosion repair efficiency on the surface of permanent magnets is up to 92%, and the mechanical properties after recovery can be restored to 97% of the original sample. This innovative coating offers a convenient, green synthesis strategy for the construction of self-healing coatings with superior anti-corrosion properties. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Polylactide/cellulose pulp composite paper with laminate structure via polylactide ultrafine fiber for eco-friendly straw.

Author

Li, Zhiying, Wang, Xuyi, Wu, Mengyun, Yao, Songjun, Guo, Jianping, Chen, Meijun, Xiong, Siwei, and Wang, Luoxin

Subjects
*LAMINATED materials, *CELLULOSE fibers, *POLYLACTIC acid, *PAPER pulp, *CELLULOSE, *RAW materials, *FIBERS, *STRAW
Abstract

Paper straws with environmental friendliness have been widely used to replace plastic straws, but their poor mechanical properties and uncontrollable deformation bring an unsatisfactory experience for users. Herein, we developed a polylactic acid/cellulose fiber (PLA/CF) ultrafine-fiber paper with a sandwich‐like structure via wet papermaking and laminated hot pressing, employing PLA ultrafine fiber and CF as raw materials. The PLA/CF ultrafine fiber paper has remarkable mechanical properties due to the tangling of the fibers and the strong hydrogen bonding that occurs between the PLA and CF during hot pressing. The test results demonstrate that the tensile strength of PLA/CFs ultrafine fiber paper can reach 60.32 N/cm, and it still retains great wet strength (27 N/cm) and stiffness (117.7 mN·cm) after long-time service in various clod and hot liquids. Besides, PLA/CF ultrafine fiber paper also displays high biodegradability, with a degradation rate of 70% after being buried in soil for 120 days. We believe that PLA/CF ultra-fine fiber paper with excellent comprehensive performance can be expected to completely replace plastic straws. [Display omitted] • The method of using environment-friendly degradable materials as raw materials. • Adopt self-assembly melt-blowing machine to raw material PLA superfine fiber. • A design combining PLA microfiber with cellulose was proposed and studied. • The straw has superior mechanical properties and thermal stability. [ABSTRACT FROM AUTHOR]

Published
2023
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