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Study of trajectory optimization using terminal-node adaptive-altered spline algorithm

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Journal of Systems Engineering and Electronics 2009年第3期20卷 551-557页

作者： Xia Qunli Guo tao qi Zaikang School of Aerospace Science and Engineering Beijing Inst. of Technology Beijing 100081 P. R. China

The advantage of using a spline function to evaluate the trajectory parameters optimization is discussed. A new method that using adaptive varied terminal-node spline interpolation for solving trajectory optimization is proposed. And it is validated in optimizing the trajectory of guided bombs and extended range guided munitions （ERGM）. The solutions are approximate to the real optimization results. The advantage of this arithmetic is that it can be used to solve the trajectory optimization with complex models. Thus, it is helpful for solving the practical engineering optimization problem.

关键词： trajectory optimization optimization control parameter optimization spline interpolation

ANALYSIS OF THE IMPLICIT-EXPLICIT ULTRA-WEAK DISCONTINUOUS GALERKIN METHOD FOR CONVECTION-DIFFUSION PROBLEMS

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Journal of Computational Mathematics 2024年第1期42卷 1-23页

作者： Haijin Wang Anping Xu qi tao School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China Beijing Computational Science Research Center Beijing 100193China

In this paper,we first present the optimal error estimates of the semi-discrete ultra-weak discontinuous Galerkin method for solving one-dimensional linear convection-diffusion ***,coupling with a kind of Runge-Kutta type implicit-explicit time discretization which treats the convection term explicitly and the diffusion term implicitly,we analyze the stability and error estimates of the corresponding fully discrete *** fully discrete schemes are proved to be stable if the time-stepτ≤τ0,whereτ0 is a constant independent of the mesh-size ***,by the aid of a special projection and a careful estimate for the convection term,the optimal error estimate is also obtained for the third order fully discrete *** experiments are displayed to verify the theoretical results.

关键词： The ultra-weak discontinuous Galerkin method Convection-diffusion Implicitexplicit time discretization Stability Error estimate

Design,fabrication and energy-saving evaluation of five-layer structure based transparent heat mirror coatings for windows application

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Building Simulation 2023年第12期16卷 2333-2342页

作者： Xiaoqiang Hong Yue Yang Huaying Chen qi tao School of Architecture and Civil Engineering Xiamen UniversityXiamen 361005China Xiamen Key Laboratory of Integrated Application of Intelligent Technology for Architectural Heritage Protection Xiamen UniversityXiamen 361005China Fujian Key Laboratory of Digital Simulations for Coastal Civil Engineering School of Architecture and Civil EngineeringXiamen UniversityXiamen 361005China School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China

Transparent heat mirror which allows the transmission of visible sunlight while reflects the infrared thermal energy is an effective building energy efficiency technology for hot climatic *** this work,a five-layer dielectric/metal/dielectric/metal/dielectric(DMDMD)coating of Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)structure is *** radiative properties of the five-layer coatings are theoretically investigated by transfer matrix *** thicknesses of the layers are optimized by using particle swarm optimization *** sample of the designed Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)coating is prepared and the building energy performance when applying the DMDMD coating in a simple office room is also investigated,taking the hot weather condition of Guangzhou,China as an *** simulated results show that the Tave+Rave value of the five-layer coating is 8%higher than that of the three-layer coating,and the long-wave emittance of the five-layer coating is 24.8%lower than that of the three-layer *** the application of the five-layer coatings on the glazed window could provide the highest energy saving rate of 8.9%when compared with the traditional low-e coatings.

关键词： transparent heat mirror spectrally selective coating energy-efficient windows building energy efficiency

Mechanism analysis of landslide of a layered slope induced by drawdown of water level

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Science China(Technological Sciences) 2005年第Z1期48卷 136-145页

作者： ZHANG Junfeng LI Zhengguo qi tao Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

The frequent drawdown of water level of Yangtze River will greatly influence the stability of the widely existing slopes in the Three Gorges reservoir zone, especially those layered ones. Apart from the fluctuating speed of water level, the different geological materials will also play important roles in the failure of slopes. Thus, it must be first to study the mechanism of such a landslide caused by drawdown of water level. A new experimental setup is designed to study the performance of a layered slope under the drawdown of water level. The pattern of landslide of a layered slope induced by drawdown of water level has been explored by means of simulating experiments. The influence of fluctuating speed of water level on the stability of the layered slope is probed, especially the whole process of deformation and development of landslide of the slope versus time. The experimental results show that the slope is stable during the water level rising, and the sliding body occurs in the upper layer of the slope under a certain drawdown speed of water level. In the process of slope failure, some new small sliding body will develop on the main sliding body, and the result is that they speed up the disassembly of the whole slope. Based on the simulating experiment on landslide of a layered slope induced by drawdown of water level, the stress and displacement field of the slope are calculated. The seepage velocity, the pore water pressure, and the gradient of pore water head are also calculated for the whole process of drawdown of water level. The computing results are in good agreement with the experimental results. Accordingly, the mechanism of deformation and landslide of the layered slope induced by drawdown of water level is analyzed. It may provide basis for treating this kind of layered slopes in practical engineering.

关键词： layered slope, landslide, drawdown of water level.

An extension of 2D Janbu's generalized procedure of slices for 3D slope stability analysis Ⅱ--Numerical method and applications

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Science China(Technological Sciences) 2005年第Z1期48卷 184-195页

This paper provides a numerical approach on achieving the limit equilibrium method for 3D slope stability analysis proposed in the theoretical part of the previous paper. Some programming techniques are presented to ensure the maneuverability of the method. Three examples are introduced to illustrate the use of this method. The results are given in detail such as the local factor of safety and local potential sliding direction for a slope. As the method is an extension of 2D Janbu’s generalized procedure of slices (GPS), the results obtained by GPS for the longitudinal sections of a slope are also given for comparison with the 3D results. A practical landslide in Yunyang, the Three Gorges, of China, is also analyzed by the present method. Moreover, the proposed method has the advantages and disadvantages of GPS. The problem frequently encountered in calculation process is still about the convergency, especially in analyzing the stability of a cutting corner. Some advice on discretization is given to ensure convergence when the present method is used. However, the problem about convergency still needs to be further explored based on the rigorous theoretical background.

关键词： slope stability analysis, three-dimensional analysis, limit equilibrium.

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Production of TiO_2 from CaTiO_3 by alkaline roasting method

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Rare Metals 2010年第2期29卷 162-167页

作者： WANG Yuanbo qi tao CHU Jinglong ZHAO Wei Graduate School of Chinese Academy of Sciences Beijing 100039 China Key laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

CaTiO3 was decomposed by alkaline roasting method for the production of *** process included alkaline roasting, water leaching and acid leaching *** the alkaline roasting step, the factors such as roasting temperature and NaOH/CaTiO3 molar ratio were investigated and 99.5% TiO2 could be extracted from *** addition, it is believed that only ion-exchange between Ca2＋ and Na＋ takes place, while the structure of TiO 32-in CaTiO3 was not destroyed during the roasting *** the acid leaching step, Ca（OH）2 could be completely leached at pH = 6-7 and Na2TiO3 was completely hydrolyzed *** crystal structure of the leached sample seemed to be affected by pH and sequent calcination ***, a flowsheet was proposed for the extraction of TiO2 from perovskite.

关键词： titanium dioxide roasting perovskite acid leaching

Removal of iron from ilmenite by KOH leaching-oxalate leaching method

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Rare Metals 2010年第1期29卷 9-15页

Oxalic acid was used for the removal of iron from the intermediates of ilmenite leached by KOH liquor. Various parameters, such as pH, temperature, initial oxalate concentration, and illumination were investigated. Meanwhile, it was found that orthorhombic crystal Ti2O2（OH）2（C2O4）-H2O formed as the leaching proceeded. Scanning electronic microscope （SEM） images implied that the formation of Ti2O2（OH）2（C2O4）.H2O with good crystallinity proceeded through three stages. Calcining Ti2O2（OH）2（C2O4）·H2O, anatase （350℃） or mtile （550℃） type TiO2 was obtained, respectively. Element analysis found that the calcined product contained 94.9% TiO2 and 2.5% iron oxide, but only about 1600 ppm dissolvable iron oxide was left, which indicates that oxalic acid was comparatively effective on iron oxide removal from the intermediates. Finally, an improved route was proposed for the upgrading of ilmenite into mtile.

关键词： ilmenite iron removal titanium oxide oxalate potassium hydroxide KOH leaching

Negative Norm Estimates for Arbitrary Lagrangian-Eulerian Discontinuous Galerkin Method for Nonlinear Hyperbolic Equations

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Communications on Applied Mathematics and Computation 2022年第1期4卷 250-270页

作者： qi tao Yan Xu Xiaozhou Li Beijing Computational Science Research Center Beijing 100193China School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China School of Mathematical Sciences University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present the negative norm estimates for the arbitrary Lagrangian-Eulerian discontinuous Galerkin(ALE-DG)method solving nonlinear hyperbolic equations with smooth *** smoothness-increasing accuracy-conserving(SIAC)filter is a post-processing technique to enhance the accuracy of the discontinuous Galerkin(DG)*** work is the essential step to extend the SIAC filter to the moving mesh for nonlinear *** the post-processing theory,the negative norm estimates are vital to get the superconvergence error estimates of the solutions after post-processing in the L2 *** the SIAC filter has been extended to nonuniform mesh,the analysis of fil-tered solutions on the nonuniform mesh is *** prove superconvergence error estimates in the negative norm for the ALE-DG method on moving *** main dif-ficulties of the analysis are the terms in the ALE-DG scheme brought by the grid velocity field,and the time-dependent function *** mapping from time-dependent cells to reference cells is very crucial in the *** numerical results also confirm the theoreti-cal proof.

关键词： Arbitrary Lagrangian-Eulerian discontinuous Galerkin method Nonlinear hyperbolic equations Negative norm estimates Smoothness-increasing accuracy-conserving filter Post-processing

Extraction behaviours of titanium and other impurities in the decomposition process of ilmenite by highly concentrated KOH solution

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International Journal of Minerals,Metallurgy and Materials 2012年第1期19卷 9-14页

作者： Yu-min Liu Hua Lv tao qi Yi Zhang College of Chemistry and Environmental Science Henan Normal University Xinxiang 453007 China Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

To effectively utilize ilmenite and recycle KOH solution, the extraction behaviours of titanium and other associated impurities in the decomposition process of ilmenite by highly concentrated KOH solution were studied. Experiments on the extraction behaviours of tita- nium as well as other associated impurities of ilmenite such as iron, silicon, calcium, and aluminium were carried out. The effects of various parameters, including reaction temperature, KOH concentration, reaction time, alkali-to-ore mass ratio, and particle size on the extraction rate of titanium and other impurities were examined. When the finely ground ore （58-75 ~tm） reacted with KOH solution （80wt%） in an al- kali-to-ore mass ratio of 7：1 at 260~C for 60 min, almost complete extraction of titanium was achieved, while the extraction rate of aluminium was 78% and that of other impurities was less than 22%. Moreover, high purity （98.2wt%） TiO2 with the anatase structure could be gained in the purification process.

关键词： ilmenite titanium dioxide potassium hydroxide leaching