Trajectory Optimization for Spacecraft Using a Second-Order Gauss Pseudo Spectral Method

Guoyong Li,Changhou Lu,Wei Pan,Qing Wang 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1

An optimal control problem for the trajectory of spacecraft under nonlinear constraints is presented. The second-order Gauss pseudo spectral method(GPM) is described for solving the problem numerically. Based on the first-order GPM, the differential matrix of the second-order GPM is derived. The dynamic equations and its constraints are approximated by the two methods. The terminal state constraints of the second-order GPM are converted to two constraints: terminal state variables and the first-order derivative constraints. The first-order GPM and second-order GPM are compared in terms of the accuracy of the state and control, the number of variables in NLP, the convergence time. A key feature of the second-order method is that it provides a more accurate and efficient way than the first-order method, due to reducing the number of variables in the nonlinear programming problem that is transcribed. A numerical example is used to identify the key differences between the two methods. The results of this study indicate that the first-order and second-order Gauss methods are very similar in accuracy, while the computational efficiency of the two methods is significantly different, for the numerical solution of nonlinear optimal control problems.

A Novel Distributed Clustering-based MDS Algorithm for Nodes Localization in WSNs

Guoyong Dai,Chunyu Miao,Yidong Li,Keji Mao,Qingzhang Chen 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.2

Localization of sensors nodes is a key and fundamental issue in wireless sensor networks due to random deployment. In this paper, we propose a tree based clustering (TBC) multidimensional scaling algorithm for wireless sensor networks with the purpose of overcoming the shortage of classical MDS algorithms in its localization accuracy and computing complexity. Clustering is adopted to degrade the problem scale in our approach and a moderate number of common nodes between clusters are kept during clustering. Inner cluster local coordinates are calculated and then mapped into global coordinates according to the tree structure formed by clustering. Simulations on MATLAB are conducted and the results show that the proposed algorithm has better localization coverage and higher accuracy than the traditional MDS based algorithms.

Spontaneous vesicle formation from trisiloxane-tailed gemini surfactant

Guoyong Wang,Zhiping Du,Dianlong Zhang,Ping Li 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

The spontaneous vesicle formation from a novel trisiloxane-tailed gemini surfactant were reported. The surface tension measurements revealed that aggregates are formed, and dynamic light scattering (DLS) measurements suggested the aggregates are vesicles. The size and morphology were observed by transmission electron microscopy (TEM). The vesicle formation was further confirmed by dye entrapment studies.

Prediction Model of Net Cutting Specific Energy Based on Energy Flow in Milling

Chunxiao Li,Guoyong Zhao,Yugang Zhao,Shuang Xu,Zhifu Zheng 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.5

Net cutting specific energy ( NCSE ) reflects the actual cutting energy efficiency. Establishing a NCSE prediction model is helpful to analyze the energy consumption characteristics of machine tools. As so far, few studies have focused on the NCSE prediction in the way of energy flow. Therefore, based on the flow direction of cutting energy, a mathematical model for predicting NCSE is proposed in this paper. During milling, the energy used for cutting can be divided into forming surface energy, material removing energy and additional load energy. Thus, the NCSE model is decomposed into three sub-models. Firstly, in the cutting process of AISI 304 stainless steel, the phase transition of austenite to martensite on the machined surface is induced by parts of cutting energy, and then work hardening occur. Furthermore, the forming surface specific energy prediction model is established based on surface hardness. Secondly, the models of material removing energy and additional load energy are developed respectively with the material removal rate and spindle speed. The above sub-models are integrated into the NCSE prediction model with the determination coefficient R 2 of 0.982, and average prediction accuracy of 96.77%. Finally, the influence of input variables on NCSE and the energy consumption proportion are revealed. Among them, the forming surface specific energy, material removing specific energy and additional load specific energy account for 8.26%, 32.63% and 59.11% on NCSE respectively. The proposed model can not only predict the overall cutting energy consumption, but also predict the energy consumption of each sub-model. The research provides a new idea for analyzing cutting energy characteristics and improving processing theory.

Preparation, characterization, and properties of novel meglumine-based polysiloxane surfactants

Yanyun Bai,Jinxing Li,Xiumei Tai,Guoyong Wang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.84 No.-

A series of meglumine-based polysiloxane surfactants, (PSim-n) with different numbers of megluminebranches were prepared. The formed surfactants were characterized by FT-IR and NMR techniques. Physiochemical properties, such as surface activity, aggregation behavior, and wettability, were closelyexamined and used to differentiate the various samples. Thefindings demonstrate that PSim-n surfactantspossess high surface activity and can wet-out a parafilm surface at all but extremely low concentrations. Furthermore, PSi6-4, the surfactant with the highest meglumine concentration, can form larger complexaggregates in aqueous solutions.

Inhibition of Toll-Like Receptor 4 Signaling Pathway Accelerates the Repair of Avascular Necrosis of Femoral Epiphysis through Regulating Macrophage Polarization in Perthes Disease

Yu Ronghui,Ma Cong,Li Guoyong,Xu Jianyun,Feng Dan,Lan Xia 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.3

BACKGROUND: Legg-Calve´-Perthes disease (LCPD) is still a refractory disease in children’s orthopedics. With the introduction of the concept of ‘‘osteoimmunology’’, the immune-inflammatory mechanisms between bone and immune system have become a research focus of LCPD. However, few studies have reported on the pathological role of inflammation- related receptors such as toll-like receptors (TLRs) as well as immune cells such as macrophages in LCPD. This study was for investigating the mechanism of TLR4 signaling pathway on the direction of macrophage polarization and the repair of avascular necrosis of femoral epiphysis in LCPD. METHODS: With GSE57614 and GSE74089, differentially expressed genes were screened. Through enrichment analysis and protein–protein interaction network, the functions of TLR4 were explored. Furthermore, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), hematoxylin & eosin (H&E) staining, micro-CT, tartrate-resistant acid phosphatase (TRAP) dyeing and western blotting were performed for determining the influences of TAK-242 (a TLR4 inhibitor) on the repair of avascular necrosis of femoral epiphysis in rat models. RESULTS: Totally 40 co-expression genes were screened as well as enriched in TLR4 signaling pathway. Immunohistochemistry and ELISA analyses certified that TLR4 facilitated macrophage polarization toward the M1 phenotype and prevented macrophage polarization toward the M2 phenotype. Besides, the results of H&E and TRAP staining, micro-CT, and western blotting showed that TAK-242 can inhibit osteoclastogenesis and promote osteogenesis. CONCLUSION: Inhibition of TLR4 signaling pathway accelerated the repair of avascular necrosis of femoral epiphysis by regulating macrophage polarization in LCPD.

Tissue distribution of marbofloxacin in pigs after a single intramuscular injection

Fan Yang,Yiming Liu,Zhili Li,Yuqin Wang,Baobao Liu,Zhensheng Zhao,Bianhua Zhou,Guoyong Wang 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.2

Tissue distribution of marbofloxacin was studied in pigs after a single intramuscular injection at 2.5 mg/kg body weight. Samples of plasma, muscle, liver, kidney, heart, lung, and muscle at the injection site were randomly collected from five pigs at 2, 6, 10, 24, 48, 72, and 96 h after administration. Marbofloxacin concentrations were determined by using high-performance liquid chromatography with ultraviolet detection and were subjected to non-compartmental analysis to obtain kinetic parameters. The elimination half-life (t1/2lz) of marbofloxacin at the injection site was 22.12 h, while those in kidney, plasma, liver, lung, heart, and muscle were 16.75, 21.48, 21.84, 24.00, 24.45, and 28.91 h, respectively. Areas under the concentration-time curve from 0 h to ∞ (AUC0–∞s) were calculated to be 31.17 hㆍmgㆍmL−1 for plasma and 32.97, 33.92, 34.78, 37.58, 42.02, and 98.80 hㆍmgㆍg−1 for heart, muscle, lung, liver, kidney, and injection site, respectively. The peak concentration (Cmax) of marbofloxacin was 1.62 µg/mL in plasma and 1.71, 1.74, 1.86, 1.93, 2.45, and 7.64 µg/g in heart, lung, muscle, kidney, liver, and injection site, respectively. The results show that marbofloxacin was fast absorbed, extensively distributed, and slowly eliminated from pigs after a single intramuscular administration.