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The Dynamics and Bifurcation Control of a Singular Biological Economic Model

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International Journal of Automation and computing 2012年第1期9卷 1-7页

作者： Ning Li Hai-Yi Sun qing-ling zhang Institute of Systems Science Northeastern University Shenyang 110819 PRC College of Science Shenyang Jianzhu University Shenyang 110168 PRC

The objective of this paper is to study systematically the dynamics and control strategy of a singular biological economic model that is described by a differential-algebraic equation. It is shown that when the economic profit passes through zero, this model exhibits the transcritical bifurcation, the Hopf bifurcation, and the limit cycle. In particular, the system undergoes the singularity induced bifurcation at the positive equilibrium, which can result in impulse. Then, state feedback controllers closer to the actual control strategies are designed to eliminate the unexpected singularity induced bifurcation and stabilize the positive equilibrium under the positive profit. Finally, numerical simulations verify the results and illustrate the effectiveness of the controllers. Also, the model with positive economic profit is shown numerically to have different dynamics.

关键词： Differential-algebraic equation transcritical bifurcation Hopf bifurcation limit cycle singularity induced bifurcation,bifurcation control.

Observers for Descriptor Systems with Slope-restricted Nonlinearities

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International Journal of Automation and computing 2010年第4期7卷 472-478页

作者： Lin-Na Zhou Chun-Yu Yang qing-ling zhang School of Business Administration Northeastern University Shenyang 110004 PRC Key Laboratory of Integrated Automation of Process Industry Ministry of Education Northeastern University Shenyang 110004 PRC Institute of Systems Science Northeastern University Shenyang 110004 PRC

This paper addresses the observer design problem for a class of nonlinear descriptor systems whose nonlinear terms are slope-restricted. The full-order observer is formulated as a nonlinear descriptor system. A linear matrix inequality （LMI） condition is derived to construct the full-order observer. The existence and uniqueness of the solution to the obtained observer system are guaranteed. Furthermore, under the same LMI condition and a common assumption, a reduced-order observer is designed. Finally, the design methods are reduced to a strict LMI problem and illustrated by a numerical example.

关键词： Descriptor systems slope-restricted nonlinearities observer linear matrix inequality (LMI)

Synchronization of Complex Networks with Coupling Delays via Adaptive Pinning Intermittent Control

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International Journal of Automation and computing 2013年第4期10卷 312-318页

作者： Hai-Yi Sun Ning Li De-Ping Zhao qing-ling zhang College of Science Shenyang Jianzhu University Institute of Systems Science Northeastern University

The problem of exponential synchronization for a class of general complex dynamical networks with nonlinear coupling delays by adaptive pinning periodically intermittent control is considered in this paper. We use the methods of the adaptive control, pinning control and periodically intermittent control. Based on the piecewise Lyapunov stability theory, some less conservative criteria are derived for the global exponential synchronization of the complex dynamical networks with coupling delays. And several corresponding adaptive pinning feedback synchronization controllers are designed. These controllers have strong robustness against the coupling strength and topological structure of the network. Using the delayed nonlinear system as the nodes of the networks, a numerical example of the complex dynamical networks with nonlinear coupling delays is given to demonstrate the effectiveness of the control strategy.

关键词： Complex networks exponential synchronization delay adaptive pinning intermittent control piecewise Lyapunov stability

Practical Stability Analysis and Synthesis of Linear Descriptor Systems with Disturbances

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International Journal of Automation and computing 2008年第2期5卷 138-144页

作者： Chun-Yu Yang Xin Jing qing-ling zhang Lin-Na Zhou Institute of Systems Science Key Laboratory of Integrated Automation of Process Industry Ministry of Education~ Northeastern University Shenyang 110004 PRC

This paper considers the problems of practical stability analysis and synthesis of linear descriptor systems subject to timevarying and norm-bounded exogenous disturbances. A sufficient condition for the systems to be regular, impulsive-free and practically stable is derived. Then the synthesis problem is addressed and a state feedback controller is designed. To deal with the computational issue, the conditions of the main results are converted into linear matrix inequality （LMI） feasibility problems. Furthermore, two optimization algorithms are formulated to improve the system performances. Finally, numerical examples are given to illustrate the obtained results.

关键词： Linear descriptor systems disturbances practical stabilization practical stability linear matrix inequality (LMI)

An Improved Approach to Delay-dependent Robust Stabilization for Uncertain Singular Time-delay Systems

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International Journal of Automation and computing 2010年第2期7卷 205-212页

作者： Xin Sun qing-ling zhang Chun-Yu Yang Zhan Su Yong-Yun Shao Institute of Systems Science Northeastern University Shenyang 110004 PRC Key Laboratory of Integrated Automation of Process Industry Ministry of Education Northeastern University Shenyang 110004 PRC Department of Computer and Mathematics Teaching Shenyang Normal University Shenyang 110034 PRC

In this paper, delay-dependent stability analysis and robust stabilization for uncertain singular time-delay systems are addressed. By using Jensen integral inequality, an improved delay-dependent criterion of admissibility for singular time-delay systems is proposed in terms of linear matrix inequality （LMI）. Our new proposed criterion is less conservative and the numerical complexity is smaller than the existing ones. Based on this criterion, a state feedback controller is designed to ensure that the uncertain singular time-delay system is admissible. Finally, three numerical examples are employed to illustrate the effectiveness of the proposed method.

关键词： Delay-dependent singular time-delay systems admissible robust stabilization.

Synthesis of Functional Polyethylene Copolymers via Reactive Monomer

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复旦学报（自然科学版） 2005年第5期44卷 867-868页

作者： Hua-yi Li Shu-qing zhang ling-zhi Wang You-liang Hu Key Laboratory of Engineering Plastics Joint Laboratory of Polymer Science and Materials Institute of Chemistry the Chinese Academy of Sciences Beijing 100080 China

Polyolefins are used widely due to their good performance and low price, but the poor compatibility and adhesion with other materials limits their applications in broader areas. Reactive monomer approach is effective to synthesize functional polyolefins[1]. In this case, olefin is copolymerized with a reactive comonomer to produce reactive intermediary which is then converted to functional group or initiator to initiate graft-from polymerization of polar monomer.

关键词：聚乙烯反作用单体共聚物烯丙基甲苯

Direct synthesis of N_(2)-unprotected five-memberedcyclic guanidines by regioselective[3+2]annulation of aziridines and cyanamides

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Organic Chemistry Frontiers 2022年第6期9卷 1574-1579页

作者： Chuan-Chuan Wang Xin-Lu Wang qing-ling zhang Juntao Liu Zhi-Wei M Zhi-Jing Liu Ya-Jing Chen School of Pharmaceutical Sciences Key Laboratory of Advanced Drug Preparation TechnologiesMinistry of Education of ChinaCo-Innovation Center of Henan Province for New Drug R&D and Preclinical SafetyZhengzhou University100 Science AvenueZhengzhou 450001HenanChina Faculty of Science Livestock Product Quality Inspection InstituteHenan University of Animal Husbandry and EconomyNo.146 Yingcai StreetZhengzhou 450044HenanChina

A novel and efficient[3+2]annulation of 2-substituted aziridines and N-tosyl cyanamides via a dominoregioselective ring-opening/5-exo-dig cyclization procedure has been developed,allowing the directpreparation of N_(2)-unprotected five-membered cyclic guanidines in good to excellent yields under mildconditions without metals and strong ***,the highly biologically interesting urea analoguescould also be conveniently obtained via hydrolysis of the produced guanidines.

关键词： membered protected guanidine

Enzyme-activatable disk-shaped nanocarriers augment tumor permeability for breast cancer combination therapy

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Nano Research 2024年第7期17卷 6400-6410页

作者： Hanming zhang Honglin Gao Yicong zhang Yikun Han qing Lin Tao Gong Xun Sun Zhirong zhang ling zhang Shiqi Huang Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry West China School of PharmacySichuan UniversityChengdu 610041China Med-X Center for Materials College of Polymer Science and EngineeringSichuan UniversityChengdu 610065China

Unique physiopathological characteristics of tumor tissues impose obstacles to the sufficient penetration of traditional nanomedicines,resulting in undesirable drug delivery efficacy and therapeutic ***,we constructed TRAIL-[NDHCPT]^(GAC),a synergistic hydroxycamptothecin(HCPT)and tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)protein co-loaded disk-shaped nanocarrier withγ-glutamyl transpeptidase *** the novel nanodisks extravasated into the tumor interstitium,theγ-glutamyl transpeptidase overexpressed on the tumor cell membranes cleaved theγ-glutamyl portions of the nanodisk surface to produce positively charged amino *** a result,the cationic nanodisks possessed stronger tumor infiltration ability through transcytosis than anionic *** and TRAIL exerted synergistic antitumor effects with better overall therapeutic *** TRAIL-[ND-HCPT]^(GAC)system performed significantly better than free HCPT and remarkably prolonged the survival of breast tumor-bearing mice with no significant toxicity.

关键词： tumor penetration combination therapy charge reversal γ-glutamyl transpeptidase nanodisk

Dynamic recrystallization mechanism, texture evolution development and mechanical characteristics of a Mg–8.7Gd–4.18Y–0.42Zr magnesium alloy by ECAP

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Progress in Natural Science:Materials International 2024年第02期34卷 376-388页

作者： ling zhang Yinglong Li School of Materials Science and Engineering Northeastern University School of Mechanical and Engineering Ningxia Institute of Science and Technology

Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures,dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K(Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400°C and 3 mm/min. Results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. In particular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 MPa, an UTS of 290 MPa, and an elongation of 14.8 %. DDRX and shear bands induce CDRX, both of which are important in plastic deformation. as well as in modifying microstructure and grain orientation during ECAP deformation.

关键词： Equal channel angular pressing Dynamic recrystallization mechanism Mechanical performance Mg-Gd-Y-Zr alloy Magnesium alloy Texture development