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19 results on '"Wu, Zitao"'

2. Rethinking: Deep-learning-based Demodulation and Decoding

Author

He, Boxiang, Wu, Zitao, and Wang, Fanggang

Subjects
Computer Science - Information Theory, Electrical Engineering and Systems Science - Signal Processing
Abstract

In this paper, we focus on the demodulation/decoding of the complex modulations/codes that approach the Shannon capacity. Theoretically, the maximum likelihood (ML) algorithm can achieve the optimal error performance whereas it has $\mathcal{O}(2^k)$ demodulation/decoding complexity with $k$ denoting the number of information bits. Recent progress in deep learning provides a new direction to tackle the demodulation and the decoding. The purpose of this paper is to analyze the feasibility of the neural network to demodulate/decode the complex modulations/codes close to the Shannon capacity and characterize the error performance and the complexity of the neural network. Regarding the neural network demodulator, we use the golden angle modulation (GAM), a promising modulation format that can offer the Shannon capacity approaching performance, to evaluate the demodulator. It is observed that the neural network demodulator can get a close performance to the ML-based method while it suffers from the lower complexity order in the low-order GAM. Regarding the neural network decoder, we use the Gaussian codebook, achieving the Shannon capacity, to evaluate the decoder. We also observe that the neural network decoder achieves the error performance close to the ML decoder with a much lower complexity order in the small Gaussian codebook. Limited by the current training resources, we cannot evaluate the performance of the high-order modulation and the long codeword. But, based on the results of the low-order GAM and the small Gaussian codebook, we boldly give our conjecture: the neural network demodulator/decoder is a strong candidate approach for demodulating/decoding the complex modulations/codes close to the Shannon capacity owing to the error performance of the near-ML algorithm and the lower complexity.

Published
2022

12. Mechanical performance optimization and microstructure analysis of similar thin AA6061-T6 sheets produced by swept friction stir spot welding

Author

Chen Xin, Yu Guishen, and Wu Zitao

Subjects
Traverse, Materials science, Tension (physics), Mechanical Engineering, Rotational speed, Welding, Radius, Industrial and Manufacturing Engineering, Computer Science Applications, law.invention, Shear (sheet metal), Control and Systems Engineering, law, Composite material, Keyhole, Spot welding, Software
Abstract

In order to increase the bonding area of friction stir spot welding (FSSW) welds, AA6061-T6 aluminum alloy was successfully welded in swept friction stir spot welding (SFSSW) process. The orthogonal experiment design was used to investigate the effect of welding parameters (tool rotation speed (ω), welding traverse speed (F), and swept radius (R)) on the joint lap shear and cross-tension performances. SFSSW welds present typical defects of keyhole, flash, and hook. Multi-objective particle swarm optimization (MOPSO) was used to determine the Pareto front and compromise solutions for the maximum lap shear failure load (LSFL) and cross-tension failure load (CTFL) simultaneously. The optimum LSFL and CTFL were 6.916 and 4.11 kN obtained under the tool rotation speed of 2050.4 rpm, the welding traverse speed of 95.48 mm/min, and the swept radius of 2.96 mm. Compared to the initial solution, the LSFL and CTFL were increased by 83.76% and 34.77% respectively. Under optimal welding parameters, the lap shear and cross tension of SFSSW welds exhibit shear and nugget pull-out fracture modes, respectively.

Published
2021

13. Effect of adhesive ductility and joint configuration on the tensile-shear behaviors of friction stir spot weld bonding joints

Author

Wu Zitao, Chen Xin, and Yu Guishen

Subjects
Materials science, Adhesive bonding, Surfaces and Interfaces, General Chemistry, Surfaces, Coatings and Films, Cohesive zone model, Mechanics of Materials, Materials Chemistry, Adhesive, Composite material, Ductility, Layer (electronics), Spot welding, Joint (geology), Extended finite element method
Abstract

This paper introduced a hybrid joining system including friction stir spot welding (FSSW) and adhesive bonding, named friction stir spot weld bonding (FSSWB). In order to avoid adhesive layer carbo...

Published
2021

14. Corrosion Resistance of CeO 2 -GO/Epoxy Nanocomposite Coating in Simulated Seawater and Concrete Pore Solutions.

Author

Liu, Xiaoyan, Wu, Zitao, Lyu, Yaoyao, Li, Tianyu, Yang, Heng, Liu, Yanqi, Liu, Ruidan, Xie, Xian, Lyu, Kai, and Shah, Surendra P.

Subjects
*EPOXY coatings, *CERIUM oxides, *MILD steel, *CORROSION resistance, *SOIL corrosion, *NANOCOMPOSITE materials, *GRAPHENE oxide, *REINFORCED concrete, *ARTIFICIAL seawater
Abstract

Reinforced concrete structures in the marine environment face serious corrosion risks. Coating protection and adding corrosion inhibitors are the most economical and effective methods. In this study, a nano-composite anti-corrosion filler with a mass ratio of CeO2:GO = 4:1 was prepared by hydrothermally growing cerium oxide on the surface of graphene oxide. The filler was mixed with pure epoxy resin at a mass fraction of 0.5% to prepare a nano-composite epoxy coating. The basic properties of the prepared coating were evaluated from the aspects of surface hardness, adhesion grade, and anti-corrosion performance on Q235 low carbon steel subjected to simulated seawater and simulated concrete pore solutions. Results showed that after 90 days of service, the corrosion current density of the nanocomposite coating mixed with corrosion inhibitor was the lowest (Icorr = 1.001 × 10−9 A/cm2), and the protection efficiency was up to 99.92%. This study provides a theoretical foundation for solving the corrosion problem of Q235 low carbon steel in the marine environment. [ABSTRACT FROM AUTHOR]

Published
2023
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16. Microstructure and Mechanical Performances Analyses on Probeless Friction Stir Spot Welds of AA6061-T6 Aluminum Sheets

Author

Yu Guishen, Chen Xin, Wu Zitao, Zhang Guanchen, and Chen Yixiong

Abstract

Probeless friction stir spot welding (PFSSW) is a variation of conventional friction stir spot welding (CFSSW), which solves the keyhole defect in CFSSW welds. In this work, four types of probeless tools were designed based on helix and spiral feature: small curvature helix (involute tool, IT), large curvature helix (archimedes tool, AT), spiral line (scroll tool, ST) and no feature (flat tool, FT). AA6061-T6 sheets with a thickness of 1.5 mm were welded using the designed probeless welding tools. The effect of tool shapes on the microstructure and mechanical properties of friction stir spot welded AA 6061-T6 aluminum alloy sheets was investigated using different rotational speeds, plunging depths and dwell times. The Taguchi method was utilized to obtain the optimal welding parameter combination for the four tools. And, the tensile-shear mechanical properties of FSSW specimens were characterized under the optimal parameters. The results show that a basin-shaped profile appeared in the weld metallography using the groove tools. The tensile shear failure load (TSFL) of IT (~6.97 kN) was higher than that of ST (~6.49 kN), AT (~6.19 kN) and FT (~5.67 kN), sequentially. Three different fracture modes, interfacial fracture, plug fracture and mixed-mode fracture were observed in the tensile-shear tests of weld specimens.

Published
2021

18. Investigation on the interaction of catalase with sodium lauryl sulfonate and the underlying mechanisms.

Author

Wang, Jing, Jia, Rui, Wang, Jiaxi, Sun, Zhiqiang, Wu, Zitao, Liu, Rutao, and Zong, Wansong

Abstract

Abstract: As a classic type of anionic surfactants, sodium lauryl sulfonate (SLS) might change the structure and function of antioxidant enzyme catalase (CAT) through their direct interactions. However, the underlying molecular mechanism is still unknown. This study investigated the direct interaction of SLS with CAT molecule and the underlying mechanisms using multi‐spectroscopic methods, isothermal titration calorimetry, and molecular docking studies. No obvious effects were observed on CAT structure and activity under low SLS concentration exposure. The particle size of CAT molecule decreased and CAT activity was slightly inhibited under high SLS concentration exposure. SLS prefers to bind to the interface of CAT mainly via van der Waals’ forces and hydrogen bonds. Subsequently, SLS interacts with the amino acid residues around the heme groups of CAT via hydrophobic interactions and might inhibit CAT activity. [ABSTRACT FROM AUTHOR]

Published
2018
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19. New immunochemical fecal occult blood test with two-consecutive stool sample testing is a cost-effective approach for colon cancer screening: Results of a prospective multicenter study in Chinese patients

Author

Li, Shirong, primary, Wang, Huahong, additional, Hu, Jichun, additional, Li, Nan, additional, Liu, Yulan, additional, Wu, Zitao, additional, Zheng, Yue, additional, Wang, Honghua, additional, Wu, Kai, additional, Ye, Hui, additional, and Rao, Jianyu, additional

Published
2006
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