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Improved Maximum Correntropy Unscented Kalman Filter for Spacecraft Attitude Estimation
Shuai Chu,Huaming Qian,Peng Ding 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6
In this article, an improved maximum correntropy unscented Kalman filter (IMCUKF) is proposed for the problem of mutation and non-Gaussian noise in the spacecraft attitude estimation system. The IMCUKF proposed in this paper transforms the above problem into a nonlinear regression problem, which is achieved by establishing a robust filter based on the maximum correntropy criterion and adaptively adjusting the prior covariance using an adaptive fading factor. In particular, the IMCUKF uses the Cauchy kernel function instead of the Gaussian kernel function to solve the problem that the maximum correntropy Kalman filter is easy to collapse due to the emergence of singular matrices. In addition, this paper applies the additive quaternion property to derive the Kalman filter gain to satisfy the constraint of quaternion normalization. Simulation results demonstrate the superiority of the proposed algorithm as compared with the existing filtering algorithm with the measurement outliers, state mutations, and non-Gaussian noises.
Hongyan Chu,Yingjie Hong,Caixia Zhang,Qi Chen,Ruilong Ding,Congbin Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7
In order to improve the printing quality, this study focused on the thermo-fluidsolid coupling process of ink roller-ink. One of the highlights of this study is to consider the influence of temperature on the rubber hyperelastic parameters, viscoelastic parameters, and ink viscosity. The other highlight is to improve the elastohydrodynamic lubrication theory and Hertz contact theory through the rubber elastic modulus, which is determined by the relaxation curve considering the temperature and working conditions. Furthermore, based on the improved theory, the thermo-fluid-solid coupling model of ink roller-ink was established. Finally, the effect of temperature on the coupling process was analyzed. The results show that under the working conditions, with increasing temperature from 20 °C to 40 °C, the contact half-width increases from 4.2335 mm to 4.4701 mm, and the minimum ink film thickness decreases from 0.5097 mm to 0.1410 mm, and the maximum ink pressure decreases from 0.6802 MPa to 0.6618 MPa.
Hongyan Chu,Ruilong Ding,Caixia Zhang,Qiang Yu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12
Ink transfer is achieved by the squeezing and rotation of two rollers, one of which is a roller coated with a viscoelastic rubber layer. In this study, the force caused by ink hydrodynamic pressure on the rubber roller during the rotation is considered, the viscoelasticity of ink and rubber is equivalently substituted by spring-damping unit, and a rolling squeezing theoretical model of two rollers is established to study the node deformation of the rubber roller. The validity of the theoretical model is verified by experiments. Results show that the deformation of the rubber roller is greatly affected by the roller rotational speed, rubber layer thickness, and nip width. The rotational speed and nip width have a significant influence on the stiffness– damping of the ink layer and the ink force, and the rubber layer thickness has a remarkable effect on the squeezing deformation between the rollers.
An investigation of local structures and EPR spectra for Cu2+ and VO2+ in biochar
Chang-Chun Ding,Xiao-Hong Chu,Zhi-Xiang Fan,Jia Fu 한국물리학회 2020 Current Applied Physics Vol.20 No.2
Electron paramagnetic resonance (EPR) technology had been adopted to analyze the structures and properties of Cu2+ and VO2+ in Biochar (BG1 and BG2), but the local structural properties have not been clarified up to now. In present work, three possible structures (orthorhombically, rhombically and tetragonally elongated octahedra) are proposed for Cu2+ in BG1 and BG2 samples, and the former seems most reasonable in view of the best agreement between the theoretical EPR parameters based on the perturbation formulae and the experimental data. As for the VO2+ center, unlike the previous assignment of the tetragonally elongated [VO5]6− cluster based on the simple formulae of EPR parameters, presently proposed tetragonally compressed [VO6]8− cluster and the high order perturbation formulae of the EPR parameters yields good agreement with the observed values. This point is also supported by the d-d optical absorption 2B1g →2B2g for tetragonally compressed octahedral 3 d1 systems.
Yin, Dongfeng,Chu, Cang,Ding, Xueying,Gao, Jing,Zou, Hao,Gao, Shen The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.1
In order to enhance the gene delivery efficiency and decrease the cytotoxicity of polyplexes, we synthesized Solutol-g-PEI by conjugating polyethyleneimine (PEI) to Solutol (polyoxyethylene (10) stearate), and evaluated its efficiency as a possible nonviral gene carrier candidate. Structural analysis of synthesized polymer was performed by using $^1H$-NMR. Gel retardation assay, particle sizes and zeta potential measurement confirmed that the new gene carrier formed a compact complex with plasmid DNA. The complexes were smaller than 150 nm, which implicated its potential for intracellular delivery. It showed lower cytotoxicity in three different cell lines (Hela, MCF-7, and HepG2) than PEI 25 kDa. pGL3-lus was used as a reporter gene, and the transfection efficiency was in vitro measured in Hela cells. Solutol-g-PEI showed much higher transfection efficiency than unmodified PEI 25 kDa.
Comparative Proteomic Analysis of Yak Follicular Fluid during Estrus
Guo, Xian,Pei, Jie,Ding, Xuezhi,Chu, Min,Bao, Pengjia,Wu, Xiaoyun,Liang, Chunnian,Yan, Ping Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.9
The breeding of yaks is highly seasonal, there are many crucial proteins involved in the reproduction control program, especially in follicular development. In order to isolate differential proteins between mature and immature follicular fluid (FF) of yak, the FF from yak follicles with different sizes were sampled respectively, and two-dimensional gel electrophoresis (2-DE) of the proteins was carried out. After silver staining, the Image Master 2D platinum software was used for protein analysis and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was performed for differential protein identification. The expression level of transferrin and enolase superfamily member 1 (ENOSF1) was determined by Western blotting for verification analysis. The results showed that 2-DE obtained an electrophoresis map of proteins from mature and immature yak FF with high resolution and repeatability. A comparison of protein profiles identified 12 differently expressed proteins, out of which 10 of them were upregulated while 2 were downregulated. Western blotting showed that the expression of transferrin and ENOSF1 was enhanced with follicular development. Both the obtained protein profiles and the differently expressed proteins identified in this study provided experimental data related to follicular development during yak breeding seasons. This study also laid the foundation for understanding the microenvironment during oocyte development.
John Man Tak Chu,Wei Xiong,Ke Gang Linghu,Yan Liu,Yan Zhang,Guan Ding Zhao,Michael G. Irwin,Gordon Tin Chun Wong,Hua Yu 한국뇌신경과학회 2018 Experimental Neurobiology Vol.27 No.6
A proportion of patients experience acute or even prolonged cognitive impairment after surgery, a condition known as postoperative cognitive dysfunction (POCD). It is characterized by impairment in different cognitive domains and neuroinflammation has been implicated as one of the inciting factors as strategies targeting inflammation tend to improve cognitive performance. Siegesbeckia Orientails L. (S. Orientails) is a common Chinese medicinal herb used for managing chronic inflammatory diseases. We investigated if pretreatment with S. Orientails before surgery confers any neuroprotective effects in postoperative animals in terms of reducing inflammation and mitigating cognitive impairment. Three-month-old male C57BL/6N mice were fed different doses of S. Orientails extract for 14 days before they underwent a laparotomy. After cognitive testing they were sacrificed on postoperative day (POD) 3. Our results showed that animals with extract pretreatment demonstrated memory improvement in a dose-dependent manner compared with control. Further, evidence for the attenuation of systemic and neuroinflammation was found in the pretreated animals, along with the inhibition of inflammatory pathways and significantly reduced tau phosphorylation in the hippocampus. Taken together, these results demonstrated a neuroprotective effect of S. Orientails in postoperative animals, indicating a therapeutic potential of S. Orientails in minimizing POCD and the possibility of utilizing this traditional Chinese medicine perioperatively.