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101.
Dahui Luo JinRong Wang Dong Shen 《Mathematical Methods in the Applied Sciences》2019,42(13):4543-4553
This paper considers the consensus tacking problem for nonlinear fractional‐order multiagent systems by presenting a PDα‐type iterative learning control update law with initial learning mechanisms. The asymptotical convergence of the proposed distributed learning algorithm is strictly proved by using the properties of fractional calculus. A sufficient condition is derived to guarantee the whole multiagent system achieving an asymptotic output consensus. An illustrative example is given to verify the theoretical results. 相似文献
102.
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104.
Qian Li Mingrui Yuan Jinyu Li Di Wei Shuangxi Mei Tao Cui Jingkun Wang Zhaoyun Zhu Xun Dong Jinfu Wan 《Magnetic resonance in chemistry : MRC》2019,57(11):934-938
Two new eudesmane derivatives, 1α,6β,9β-trihydroxy-eudesm-3-ene-1-O-β-d -glucopyranoside ( 1 ) and 1α,6β,9β-trihydroxy-eudesm-3-ene-1-(6-cinnamoyl)-O-β-d -glucopyranoside ( 2 ) were discovered from Merremia yunnanensis. The structures were elucidated by analysis of their spectroscopic data including HR-ESI-MS, 1D, and 2D NMR. It should be noted that this is the first report about structure elucidation and NMR assignment of compounds from M. yunnanensis. 相似文献
105.
Based on the principle of acoustic levitation,a single-axis ultrasonic levitation system(SAULS) with convex sides was designed.A normal SAULS only provides a levitation force(LF) against the gravity of the sample.While,such systems also provide an annular clamping force(ACF) surrounding the levitated samples,and improve levitation stability of samples in the standing wave field.Using the finite-difference time-domain method,we investigated the force distributions in different resonance cavities and the factors that influence the magnitude of the levitation force in optimizing the SAULS and the ACF.The theoretical analyses and experimental results indicate that the stability of levitation in this special SAULS is improved with the ACF from its designed convex-side feature.It can be developed into a simple device in levitating and moving samples steadily in related experiments and applications. 相似文献
106.
A variety of heterobiaryl compounds have been synthesized by the Suzuki‐Miyaura coupling reactions of heteroaryl halides with potassium aryltrifluoroborates. Pd (OAc)2 was found to be highly efficient for the Suzuki‐Miyaura coupling reactions of various heteroaryl halides with potassium aryltrifluoroborates in aqueous systems, delivering the corresponding heterobiaryl compounds in good to excellent yields. 相似文献
107.
Cong Hu Bingyang Dong Li Liu 《Journal of polymer science. Part A, Polymer chemistry》2019,57(12):1333-1343
We report on the preparation of reduction‐responsive amphiphilic block copolymers containing pendent p‐nitrobenzyl carbamate (pNBC)‐caged primary amine moieties by reversible addition–fragmentation chain transfer (RAFT) radical polymerization using a poly(ethylene glycol)‐based macro‐RAFT agent. The block copolymers self‐assembled to form micelles or vesicles in water, depending on the length of hydrophobic block. Triggered by a chemical reductant, sodium dithionite, the pNBC moieties decomposed through a cascade 1,6‐elimination and decarboxylation reactions to liberate primary amine groups of the linkages, resulting in the disruption of the assemblies. The reduction sensitivity of assemblies was affected by the length of hydrophobic block and the structure of amino acid‐derived linkers. Using hydrophobic dye Nile red (NR) as a model drug, the polymeric assemblies were used as nanocarriers to evaluate the potential for drug delivery. The NR‐loaded nanoparticles demonstrated a reduction‐triggered release profile. Moreover, the liberation of amine groups converted the reduction‐responsive polymer into a pH‐sensitive polymer with which an accelerated release of NR was observed by simultaneous application of reduction and pH triggers. It is expected that these reduction‐responsive block copolymers can offer a new platform for intracellular drug delivery. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1333–1343 相似文献
108.
In this paper, an unstable linear time invariant (LTI) ODE system is stabilized exponentially by the PDE compensato—a wave equation with Kelvin‐Voigt (K‐V) damping. Direct feedback connections between the ODE system and wave equation are established: The velocity of the wave equation enters the ODE through the variable vt(1,t); meanwhile, the output of the ODE is fluxed into the wave equation. It is found that the spectrum of the system operator is composed of two parts: point spectrum and continuous spectrum. The continuous spectrum consists of an isolated point , and there are two branches of asymptotic eigenvalues: the first branch approaches to , and the other branch tends to ?∞. It is shown that there is a sequence of generalized eigenfunctions, which forms a Riesz basis for the Hilbert state space. As a consequence, the spectrum‐determined growth condition and exponential stability of the system are concluded. 相似文献
109.
Three multinuclear Cu (II), Zn (II) and Cd (II) complexes, [Cu2(L)(μ‐OAc)]·CHCl2 ( 1 ), [Zn2(L)(μ‐OAc)(H2O)]·3CHCl3 ( 2 ) and [{Cd2(L)(OAc)(CH3CH2OH)}2]·2CH3CH2OH ( 3 ) with a single‐armed salamo‐like dioxime ligand H3L have been synthesized, and characterized by FT‐IR, UV–vis, X‐ray crystallography and Hirshfeld surfaces analyses. The ligand H3L has a linear structure and C‐H···π interactions between the two molecules. The complex 1 is a dinuclear Cu (II) complex, Cu1 and Cu2 are all five‐coordinate possessing distorted square pyramidal geometries. The complex 2 also forms a dinuclear Zn (II) structure, and Zn1 and Zn2 are all five‐coordinate bearing distorted trigonal bipyramidal geometries. The complex 3 is a symmetrical tetranuclear Cd (II) complex, and Cd1 is a hexa‐coordinate having octahedral configuration and Cd2 is hepta‐coordinate with a pentagonal bipyramidal geometry, and it has π···π interactions inside the molecule. In addition, fluorescence properties of the ligand and its complexes 1 – 3 have also been discussed. 相似文献
110.