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Four new lanostane triterpenoids featuring extendedπ-conjugated systems from the stems of Kadsura coccinea
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作者 Qi-Qi Zhang Kun Hu +1 位作者 Han-Dong Sun Pema-Tenzin Puno 《Natural Products and Bioprospecting》 CSCD 2023年第1期607-614,共8页
Four new 14(13→12)-abeolanostane triterpenoids featuring extendedπ-conjugated systems,kadcoccitanes E-H(1-4),were obtained from the stems of Kadsura coccinea through using a HPLC−UV-guided approach.Their structural ... Four new 14(13→12)-abeolanostane triterpenoids featuring extendedπ-conjugated systems,kadcoccitanes E-H(1-4),were obtained from the stems of Kadsura coccinea through using a HPLC−UV-guided approach.Their structural and configurational determination was accomplished through extensive spectroscopic analysis coupled with quantum chemical calculations.Kadcoccitanes E-H were tested for their cytotoxic activities against five human tumor cell lines(HL-60,A-549,SMMC-7721,MDA-MB-231,SW-480)but none of them exhibited activities at the concentration 40μM. 展开更多
关键词 Kadsura coccinea Lanostane triterpenoids extendedπ-conjugated systems Quantum chemical calculation
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Dynamic Stability Analysis of Linear Time-varying Systems via an Extended Modal Identification Approach 被引量:2
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作者 Zhisai MA Li LIU +3 位作者 Sida ZHOU Frank NAETS Ward HEYLEN Wim DESMET 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第2期459-471,共13页
The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system mo... The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the "frozen-time" assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system's stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes. 展开更多
关键词 Linear time·varying systems · extended modal identification · Dynamic stability analysis · Time·varying modes
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EXTENDED SYSTEM, BIFURCATION PROBLEM AND HIGH ORDER SINGULARITIES
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作者 胡国庆 李开泰 《Acta Mathematica Scientia》 SCIE CSCD 1995年第1期65-73,共9页
In this paper, we consider two extended systems. When using them for the two parameter bifurcation problems, the simple bifurcation point with regard to lambda on turn into the simple turning point with. regard to mu.... In this paper, we consider two extended systems. When using them for the two parameter bifurcation problems, the simple bifurcation point with regard to lambda on turn into the simple turning point with. regard to mu. Simple high orde bifurcation point is first studied without using the symmetry condition. 展开更多
关键词 2-PARAMETER NONLINEAR PROBLEMS extended systems BIFURCATION PROBLEM SIMPLE TURNING POINT SIMPLE HIGH ORDER BIFURCATION POINT
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A NEW APPROACH FOR THE COMPUTATION OF HOPF BIFURCATION POINTS 被引量:1
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作者 叶瑞松 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第11期1300-1307,共8页
A new approach is proposed to compute Hopf bifurcation points. The method could produce small extended systems and therefore could reduce the computational effort and storage. One numerical example is presented to dem... A new approach is proposed to compute Hopf bifurcation points. The method could produce small extended systems and therefore could reduce the computational effort and storage. One numerical example is presented to demonstrate that the method is efficient. 展开更多
关键词 Hopf bifurcation points extended systems
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A Novel Mechanism for TRF of Plant-wide Material Flows in Process Industry MES
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作者 朱炜 朱峰 荣冈 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第4期418-428,共11页
This paper is standing on the recent viewpoint originated from relevant industrial practices that well or-ganized tracing, representing and feedback(TRF) mechanism of material-flow information is crucial for system ut... This paper is standing on the recent viewpoint originated from relevant industrial practices that well or-ganized tracing, representing and feedback(TRF) mechanism of material-flow information is crucial for system utility and usability of manufacturing execution systems(MES), essentially, for activities on the side of multi-level decision making and optimization mainly in the planning and scheduling. In this paper, we investigate a key issue emphasized on a route of multi-level information evolution on the side of large-scale feedback, where material-flow states could evolve from the measuring data(local states) to networked event-type information cells(global states) and consequently to the key performance indicators(KPI) type information(gross states). Importantly, with adapta-bilities to frequent structural dynamics residing in running material flows, this evolving route should be modeled as a suit of sophisticated mechanism for large-scale dynamic states tracking and representing so as to upgrade accu-racy and usability of the feedback information in MES. To clarify inherent complexities of this evolving route, the investigated issue is demonstrated from extended process systems engineering(PSE) point of view, and the TRF principles of the multi-level feedback information(states) are highlighted under the multi-scale methodology. As the main contribution, a novel mechanism called TRF modeling mechanism is introduced. 展开更多
关键词 extended process systems engineering manufacturing execution systems material flow modeling method
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