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An Iterative Method for Optimal Feedback Control and Generalized HJB Equation

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IEEE/CAA Journal of Automatica Sinica 2018年第5期5卷 999-1006页

作者： Xuesong chen xin chen the school of applied mathematics guangdong university of technologyGuangzhou 510006China the school of electromechanical engineering guangdong university of technologyGuangzhou 510006China

Abstract--In this paper, a new iterative method is proposed to solve the generalized Hamilton-Jacobi-Bellman （GHJB） equation through successively approximate it. Firstly, the GHJB equation is converted to an algebraic equation with the vector norm, which is essentially a set of simultaneous nonlinear equations in the case of dynamic systems. Then, the proposed algorithm solves GHJB equation numerically for points near the origin by considering the linearization of the non-linear equations under a good initial control guess. Finally, the procedure is proved to converge to the optimal stabilizing solution with respect to the iteration variable. In addition, it is shown that the result is a closed-loop control based on this iterative approach. Illustrative examples show that the update control laws will converge to optimal control for nonlinear systems. Index Terms--Generalized Hamilton-Jacobi-Bellman （HJB） equation, iterative method, nonlinear dynamic system, optimal control.

关键词： Generalized Hamilton-Jacobi-Bellman(HJB) equation iterative method nonlinear dynamic system optimal control

1-Pyrenecarboxaldehyde thiosemicarbazone:A novel fluorescent molecular sensor towards mercury(Ⅱ) ion

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Chinese Chemical Letters 2010年第9期21卷 1124-1128页

作者： Xue Mei Wang hua Yan xin Lu Feng Yong chen Department of Chemistry and Material Engineering Logistic Engineering University Chongqing 401311 China Department of Applied Oil Engineering Logistic Engineering University Chongqing 401311 China Department of Barracks Management & Environmental Engineering Logistic Engineering University Chongqing 401311 China

A novel and simple fluorescent molecular sensor,1-pyrenecarboxaldehyde thiosemicarbazone（Hpytsc）,was *** higher sensitivity and selectivity to mercury（Ⅱ） ion were studied through absorption and emission *** UV-vis spectra show that the increasing mercury（Ⅱ） ion concentrations result in the decreasing absorption *** fluorescence monomer emission of Hpytsc is enhanced upon binding mercury（Ⅱ） ion,which should be due to the 1：1 complex formation between Hpytsc and metal ion.

关键词： Fluorescence sensor Mercury(Ⅱ) ion Pyrene derivatives Thiosemicarbazone

A VERTICAL 2-D NUMERICAL SIMULATION OF SUSPENDED SEDIMENT TRANSPORT

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Journal of Hydrodynamics 2007年第2期19卷 217-224页

作者： ZHANG Jing-xin LIU hua Department Of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

Numerical simulation of sediment transport and bed evolution has become an important technique in the sediment research. In this article, a numerical model of suspended sediment transport was proposed, which was established in the vertical σ coordinate for fitting the free surface and bottom. In the research of the sediment transport, the predominant factors were found to be the eddy diffusion, the settling velocity, the bed condition and so on. By the aid of the model in the article, the contribution of the Rouse parameter to the vertical profile of sediment concentration was clarified, which was identical to the theoretical results. In the comparison of the numerical results with laboratory data, the agreement between experimental data and numerical results was reached except for some data. And the possible reasons for the disagreement were discussed.

关键词： suspended sediment transport 2-D numericalmodel σ coordinate

Unsteady simulation for a high-speed train entering a tunnel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第12期12卷 957-963页

作者： xin-hua LI Jian DENG Da-wei chen Fang-fang XIE Yao ZHENG School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China National Engineering Laboratory for System Integration of High-Speed Train （South） CSR Qingdao Sifang Co. Ltd Qingdao 266111 China

In order to study the unsteady aerodynamics effects in railway tunnels,the 3D Reynolds average Navier-Stokes equations of a viscous compressible fluid are solved,and the two-equation k-ε model is used in the simulation of turbulence,while the dynamic grid technique is employed for moving *** focus on obtaining the changing tendencies of the aerodynamic force of the train and the aerodynamic pressures on the tunnel wall and train surface,and discovering the relationship between the velocity of the train and the intensity of the micro pressure wave at the tunnel *** is shown that the amplitudes of the pressure changes in the tunnel and on the train surface are both approximately proportional to the square of the train speed,so are the microwave and the drag of the train.

关键词： High-speed train Aerodynamics Railway tunnel Numerical analysis

Upregulation of erythropoietin and erythropoietin receptor in castration-resistant progression of prostate cancer

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Asian Journal of Andrology 2020年第4期22卷 422-426页

作者： chen Ye Guang-hua chen xin chen Sheng-Fei Qin Min-Feng Shi Tie Zhou Department of Urology Changhai HospitalSecond Military Medical UniversityShanghai 200433China Reproductive Center Changhai HospitalSecond Military Medical UniversityShanghai 200433China

Hypoxia-induced erythropoietin signaling plays an important role in tumor growth and *** the present study,we investigated the contribution of erythropoietin signaling pathway to castration-resistant prostate cancer and the development of a neuroendocrine *** staining showed that the erythropoietin and erythropoietin receptor scores in castration-resistant prostate cancer and androgen-dependent prostate cancer were 7.55 versus 4.5 and 7.45 versus 5.9,respectively(P<0.001).Furthermore,a cell proliferation assay was conducted,and the differential expression of erythropoietin and erythropoietin receptor in LNCaP cells and hypoxia-induced LNCaP cells was evaluated using western blot and quantitative real-time *** proliferation capacity of hypoxia-induced LNCaP cells was similar in cultures of both fetal bovine serum and charcoal-stripped fetal bovine serum,suggesting that LNCaP cells acquired hypoxia-induced androgen-independent *** 2 weeks of hypoxic culture,LNCaP cells showed a neuroendocrine cell change and increased expression of neuron-specific enolase,erythropoietin,and erythropoietin receptor;knockdown of erythropoietin receptor reversed the hypoxia-induced upregulation of neuron-specific enolase in the LNCaP *** conclusion,the concurrent upregulation of erythropoietin and erythropoietin receptor in castration-resistant prostate cancer suggests that the erythropoietin/erythropoietin receptor autocrine loop plays an important role in the progression of castration resistance and is responsible for the development of a neuroendocrine phenotype.

关键词： erythropoietin erythropoietin receptor hypoxia prostatic neoplasm

Trimethylamine Adsorption Mechanism on Activated Carbon and Removal in Water and Oyster Proteolytic Solution

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Journal of Ocean University of China 2021年第6期20卷 1578-1586页

作者： chen Deke WAN Peng CAI Bingna YE Ziqing chen hua chen xin SUN Huili PAN Jianyu Key Laboratory of Tropical Marine Bio-Resource and Ecology/Guangdong Key Laboratory of Marine Meteria Medica South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Innovation Academy of South China Sea Ecology and Environmental Engineering(ISEE) Chinese Academy of SciencesGuangzhou 510000China School of Environment and Chemical Engineering Foshan UniversityFoshan 528000China University of Chinese Academy of Sciences Beijing 100049China

In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless *** results showed that columnar AC(CAC)had a clear scale and honeycomb structures with few fragments and micropores,contributing to superior TMA removal capacity compared to granular AC(GAC)(71.67%for 6.0 mm CAC and 69.92%for 40–60 mesh GAC).In addition,the process of adsorption was accompanied by desorption,and the recommended absorbed time was 120–180 *** short time to achieve equilibrium indicated that adsorption was kinetically controlled,and pseudo-second-order kinetics was more appropriate than pseudo-first-order kinetics in explaining the adsorption mechanism in both water and oyster enzymatic *** intraparticle diffusion model presented that the adsorption processes could be divided into three steps for GAC and two steps for *** adsorption processes were consistent with the Freundlich model,indicating the existence of physisorption and chemisorption as multilayer *** results indicated that AC,especially CAC,has great potential for TMA elimination in aquatic product processing.

关键词： trimethylamine activated carbon adsorption mechanism oyster proteolytic solution

Tracking with nonlinear measurement model by coordinate rotation transformation

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Science China(Technological Sciences) 2014年第12期57卷 2396-2406页

作者： ZENG Tao LI Chun Xia LIU Quan hua chen xin Liang School of Information and Electronics Beijing Institute of Technology

A new filtering method is proposed to accurately estimate target state via decreasing the nonlinearity between radar polar measurements(or spherical measurements in three-dimensional(3D) radar) and target position in Cartesian coordinate. The degree of linearity is quantified here by utilizing correlation coefficient and Taylor series expansion. With the proposed method, the original measurements are converted from polar or spherical coordinate to a carefully chosen Cartesian coordinate system that is obtained by coordinate rotation transformation to maximize the linearity degree of the conversion function from polar/spherical to Cartesian coordinate. Then the target state is filtered along each axis of the chosen Cartesian coordinate. This method is compared with extended Kalman filter(EKF), Converted Measurement Kalman filter(CMKF), unscented Kalman filter(UKF) as well as Decoupled Converted Measurement Kalman filter(DECMKF). This new method provides highly accurate position and velocity with consistent estimation.

关键词： target tracking Kalman filtering nonlinear filtering decoupled nonlinearity

Microstructure and mechanical properties of BFe10 cupronickel alloy tubes fabricated by a horizontal continuous casting with heating-cooling combined mold technology

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 339-347页

作者： Jun Mei xin-hua Liu Jian-xin Xie Key Laboratory for Advanced Materials Processing (Ministry of Education) University of Science and Technology Beijing Beijing 100083 China Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China

A new horizontal continuous casting method with heating-cooling combined mold （HCCM） technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe 10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting （cooling mold casting） were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the pro- duction efficiency of a BFel0 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of {012}〈 621 〉. Compared with cooling mold casting （6 = 36.5%）, HCCM can improve elongation （3 = 46.3%） by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe 10 cupronickel alloy tube.

关键词： cupronickel alloys thin-wall tubes continuous casting microstructure mechanical properties

Relationship Between the N Concentration of the Leaf Subtending Boll and the Cotton Fiber Quality

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Journal of Integrative Agriculture 2012年第12期11卷 2013-2019页

作者： WANG You-hua ZHAO xin-hua chen Bing-lin GAO Xiang-bin ZHOU Zhi-guo College of Agriculture Nanjing Agricultural University Cotton Research Institute Chinese Academy of Agricultural Sciences

This experiments were conducted in Nanjing （118~50＂E, 32~02＂N） and Xuzhou （117~11 ＂E, 34~15＂N）, Jiangsu Province, China, to study the response of fiber quality to the N concentration of the leaf subtending boll in cotton （Gossypium hirsutum L.）. Results suggested that the N dilution curve of the leaf subtending boll can accurately indicate the stage- specific plant N status for fiber development. Fiber strength is likely to be the most variable fiber quality index responding to the leaf N variation which is different in cultivars. Fiber length was the most stable index among strength, length, micronaire, and elongation. There existed an optimum leaf N concentration for fiber strength development in each stage. The optimum leaf N regression curve was very close to the N dilution curve in the middle positional fruiting branches under the 240 kg N ha-1 soil N application rate.

关键词： cotton fiber quality leaf N concentration cellulose