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Robust H_∞ Control of Uncertain Linear Systems with Multiple State Delays—LMI approach

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Journal of China Textile University(English Edition) 1998年第3期15卷 46-49页

作者：程储旺孙优贤汤兵勇 China Textile Univ Shanghai China

This paper deals with the problem of robust H∞ control for uncertain systems with multiple state delays. The parameter uncertainties are unknown but norm - bounded. An LMI based method is developed for robust H∞ stabilization for a class of uncertain systems with multiple state delays via linear memoryless state feedback control. The resuits depend on the size of the delays and are given in terms of linear matrix inequalities, so they are less con. servative than those of delay - independent.

关键词： uncertain system robust control H∞ control time delay LMl approach.

PERTURBATION approach.TO SOLVING THE RADIATIVE TRANSFER EQUATION FOR OCEAN

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Science China Mathematics 1991年第5期34卷 633-640页

作者：游铭长 Department of Physics East China Normal University Shanghai 200062 PRC

A new analytical method, the perturbation approach. is presented, which can widely beused to solve the radiative transfer equation in Case 1 sea waters. A computation example isprovided, whose results are in good agreement with those obtained with other *** on the general solution obtained in this way, an analytical relationship is found be-tween the shape of the asymptotic state of the radiance and the inherent optical propertiesof sea waters.

关键词： radiative transfer equation perturbation approach.

Liquid crystal-based structural color actuators

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Light(Science & Applications) 2022年第9期11卷 1994-2017页

作者： Pei Zhang Laurens T.de Haan Michael G.Debije Albert P.H.J.Schenning Stimuli-responsive Functional Materials and Devices Department of Chemical Engineering and ChemistryEindhoven University of TechnologyP.O.Box 5135600 MB EindhovenThe Netherlands Institute for Complex Molecular Systems Eindhoven University of TechnologyDen Dolech 25600 MB EindhovenThe Netherlands SCNU-TUE Joint Lab of Device Integrated Responsive Materials(DIRM) National Center for International Research on Green OptoelectronicsSouth China Normal UniversityGuangzhou 510006China

Animals can modify their body shape and/or color for protection,camouflage and *** adaptability has inspired fabrication of actuators with structural color changes to endow soft robots with additional *** liquid crystal-based materials for actuators with structural color changes is a promising *** this review,we discuss the current state of liquid crystal-based actuators with structural color changes and the potential applications of these structural color actuators in soft robotic devices.

关键词： structural crystal approach.

On the shepherding of Uranian epsilon ring

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Science China Mathematics 2000年第6期43卷 666-672页

作者：周济林孙义燧 Bambi Hu Department of Astronomy Nanjing University Nanjing 210093 China Department of Physics and Center for Nonlinear studies Hong Kong Baptist University Hong Kong China Department of Astronomy Nanjing University Nanjing 210093 China Department of Physics and Center for Nonlinear studies Hong Kong Baptist UniversityHong KongChina Department of PhysicsUniversity of HoustonHouston TX 77204USA Correspondence should be addressed to Zhou Jilin

To explain the long-term existence of Uranian narrow rings, we study the dynamical evolution of Uranian epsilon ring under the influence of its two shepherding satellites: Cordelia and Ophelia. The model of planar-elliptic restricted three-body problem is employed, in which the three bodies are Uranus, a satellite and a test particle. Dissipations due to interparticle collisions are also taken into consideration. A mapping system has been obtained based on the differential equation system. Numerical results show that only those particles originally lying in the libration region of the resonance can be shepherded. The size of the libration region depends mainly on the orbital eccentricity and mass of the shepherd satellite. For the outer shepherd Ophelia with larger orbital eccentricity, if its mass is a third of the nominal mass 2.5 × 1019 g, most of the orbits are regular and the outer edge of the ring can be shepherded, but more fuzzy than the inner edge. Thus we infer that Ophelia has a smaller mass.

关键词： Uranian rings shepherding mechanism mapping approach.

Rational fraction model for regularized inverse dynamics of a flexible manipulator

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Science China(Technological Sciences) 1998年第6期41卷 600-607页

作者：王国利 Department of Computer Science Shantou University Shantou China National Laboratory of Intelligent Robot Control Nankai University Tianjin China

The rational fraction model for the regularized inverse dynamics of a flexible manipulator is presented, the effect of this model on alleviating the ill posed behavior of the calculated torque is demonstrated, and the implication of the regularization parameter selection on the trade off between the tracking accuracy and the frequency bandwidth of the calculated torque is addressed as well. The validity of the proposed method is illustrated by means of a computer numeric simulation.

关键词： flexible manipulators inverse dynamics regularization approach.

Determination of stress intensity factors in ultrasonic fatigue loading

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Science China(Technological Sciences) 1996年第2期39卷 141-147页

作者：倪金刚张学仁聂景旭 Department of Jet Propulsion 405 Beijing University of Aeronautics and AstronauticsBeijing 100083China

The application of displacement and energy approach.s to the determination of stress intensity factors in ultrasonic fatigue crack growth (fcg) studies is *** particular advantages as well as the limitations of the two approach.s are *** types of ultrasonic fatigue loading with different stress ratios are exerted on the specimen respectively: the ultrasonic fatigue loading with a stress ratio R=-1 and the ultrasonic fatigue excitations superposed upon a static mean stress with R>-1 From comparison the conclusion is formed that the energy approach.developed in the investigation is more accurate,concise and suitable than commonly adopted approach.s and/or formulas *** fcg data on a titanium alloy Ti-6Al-4V and the characteristic mechanism of the ultrasonic fcg are investigated.

关键词： ultrasonic fatigue stress intensity factors 3-D finite element energy approach.

Analysis on cohesive crack opening displacement considering the strain softening effect

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2 & ZHAO Xiqiang3 1. Mechanics Department, Shandong University of Technology, Zibo 255049, China 2. Civil Engineering Department, Dalian University of Technology, Dalian 116024, China 3. Mathematics Department, Ocean University of China, Qingdao 266071, China Mechanics Department Shandong University of Technology Zibo China Civil Engineering Department Dalian University of Technology Dalian China Mathematics Department Ocean University of China Qingdao China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

An SCF-CI method for determining the potential energy surface of a triatomic molecule

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Science China Chemistry 1996年第4期39卷 439-448页

作者：谢代前鄢国森 Department of Chemistry Sichuan University Chengdu 610064 ChinaDepartment of Chemistry Sichuan University Chengdu 610064 China

A self-consistent-field (SCF)-configuration interaction (CI) (SCF-CI) method for determining the potential energy surface of a triatomic molecule from the observed vibrational band origins has been suggested. By this method, the SCF-CI procedure in the internal coordinates is used to calculate the vibrational bond origins and their first derivatives with respect to parameters in the potential energy function using the exact vibrational Hamiltonian, and the optimizer LMF in the nonlinear-squares problem is employed to optimize parameters in the potential energy function. This approach.is used to optimize the potential energy function of the water molecule. The standard deviation of this fitting to the 70 observed band origins is 1.154cm-1.

关键词： triatomic molecule potential energy function highly excited vibrational states SCF-CI approach.

MECHANISM OF C- H INSERTION OF BICYCLOBUTANYLIDENE

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Chinese Science Bulletin 1990年第5期35卷 388-392页

作者：王秉泽邓从豪 Institute of Theoretical Chemistry Shandong University Jinan 250100 PRC

Ⅰ. INTRODUCTIONThe intramolecular C—H insertion of cyclic carbene is a short and valuable synthetic route for highly strained small-and poly-ring compounds. However, the reaction mechanism is not clear. Jones considered that n-approach.mechanism is attainable, whereas an end-on approach.is sterically impossible. The MINDO/3 calculations by Dewar and Chiu respectively showed that the reaction of bicyclobutanylidene 1 produced

关键词： C—H Insertion concerted reaction end-on approach.