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81.
Mohammad Saleh Tavazoei Mohammad Haeri Sadegh Bolouki Milad Siami 《Nonlinear dynamics》2009,55(1-2):179-190
This paper deals with a fractional calculus based control strategy for chaos suppression in the 3D chaotic systems. It is assumed that the structure of the controlled chaotic system has only one control input. In the proposed strategy, the controller has three tuneable parameters and the control input is constructed as fractional-order integration of a linear combination of linearized model states. The tuning procedure is based on the stability theorems in the incommensurate fractional-order systems. To evaluate the performance of the proposed controller, the design method is applied to suppress chaotic oscillations in a 3D chaotic oscillator and in the Chen chaotic system. 相似文献
82.
New equation for calculating total interaction energy in one noncyclic ABC triad and new insights into cooperativity of noncovalent bonds 下载免费PDF全文
In this work, a new equation consist of A???B, B???C, A???BC, and AB???C interactions is proposed for calculating the total interaction energy of noncyclic ABC triads. New equations are also proposed for calculating the changes in values of A???B and B???C interactions on the formation of triad from the corresponding dyads. The advantages of equations proposed here in comparison with many‐body interaction energy approach are discussed. All proposed equations were tested in F3MLi???NCH???HLH and F3MLi???HLH???HCN (M = C, Si; L = Be, Mg) as well as H3N???XY???HF (X, Y = F, Cl, Br) noncyclic A???B???C triads. The data show that the total cooperativity of triad correlates well with the sum of the changes in values of A???B and B???C interactions calculated through new equations proposed here. © 2016 Wiley Periodicals, Inc. 相似文献
83.
84.
A one-pot, three-component condensation reaction of an isatin, isoxazole, and barbituric acid in water to give spirooxindoles in high yields, at 70 °C temperature, using a catalytic amount of p-toluene sulfonic acid, is described. 相似文献
85.
86.
Let $G$ be a graph with the vertex set $V(G)$ and the edge set $E(G)$ . A function $f: E(G)\longrightarrow \{-1, 1\}$ is said to be a signed star dominating function of $G$ if $\sum _{e \in E_G(v)}f (e)\ge 1 $ , for every $v \in V(G)$ , where $E_G(v) = \{uv\in E(G)\,|\,u \in V (G)\}$ . The minimum values of $\sum _{e \in E_G(v)}f (e)$ , taken over all signed star dominating functions $f$ on $G$ , is called the signed star domination number of $G$ and denoted by $\gamma _{SS}(G)$ . In this paper we determine the signed star domination number of regular multigraphs. 相似文献
87.
β-Cyclodextrin (β-CD) supramolecule was found to be a convenient, green and economical tool in one-pot synthesis of rhodanine scaffolds as a highly efficient mediating agent in aqueous media in which the reaction accelerated to complete in 15 min and room temperature. In this work, amines reacted with equimolar ratio of CS2 (not excess ratio of CS2) and then with activated acetylenes in the presence of β-CD in aqueous media. 相似文献
88.
Multicomponent synthesis of biologically and pharmaceutically interested α-aminophosphonates derived from different amines and aromatic aldehydes was catalysed by biodegradable and easily accessible cellulose sulphuric acid. The catalyst could be prepared by functionalisation of cellulose in a simple step. Cellulose sources are bioavailable and rich among the bio-compounds. 相似文献
89.
An efficient diketene ring-opening synthesis of polyhydroquinoline derivatives using SBA-15 sulfonic acid modified mesoporous substrates a green and reusable catalyst in a single-pot four-component coupling reaction of diketene,alcohol,enamine,and aldehydes is reported.Dihydropyridine derivatives based on neat adduct of diketene,alcohols and aldehydes using SBA-15/SO3H nanoreactor as catalyst via a four-component reactions are also synthesized.The advantages of the present method include the use of a small amount catalyst,simple procedure with an easy filterable work-up,waste-free,green and direct synthetic method with an excellent yield of products with efficient use of catalyst and a short reaction time. 相似文献
90.
Seyyed Javad Sabounchei Mohsen Ahmadi Zahra Nasri Esmaeil Shams Sadegh Salehzadeh Yasin Gholiee Roya Karamian Mostafa Asadbegy Sepideh Samiee 《Comptes Rendus Chimie》2013,16(2):159-175
The non-symmetric phosphorus ylides and their Pd(II) complexes have been synthesized as potential antioxidant and antibacterial compounds and their structures were elucidated using a variety of physicochemical techniques. The reaction of 1 equiv non-symmetric phosphorus ylides, Ph2PCH2PPh2C(H)C(O)PhX (X = Br (Y1), Cl (Y2), NO2 (Y3), OCH3 (Y4)) with [Pd(dppe)Cl2] (M1), followed by treatment with 2 equiv AgOTf led to monomeric chelate complexes, [(dppe)Pd(Ph2PCH2PPh2C(H)C(O)PhX)] (OSO2CF3)2 (X = Br (C1), Cl (C2), NO2 (C3), OCH3 (C4)), which contain a five-membered P,P chelate ring in one side and a five-membered P,C chelate ring in the other side. Palladium ion complexes were synthesized and investigated by cyclic voltammetry, FT-IR, UV–visible, multinuclear (1H, 31P and 19F) NMR, thermal analysis and ESI-mass spectroscopic studies. Some complexes and ligands have been studied by powder XRD and single crystal X-ray diffraction techniques. FT-IR and 31P NMR studies revealed that the ylides Y are coordinated to the metal ions via the terminal phosphorus (Pc) of the ylides and methene group (CH). The proposed coordination geometry around the Pd atom in these complexes is defined as slightly distorted square planar by UV-Visible and DFT studies. Thermal stability of all complexes was also shown by TG/DTG methods. Furthermore, the electrochemical behavior of the complexes was investigated by cyclic voltammetry. The results indicate that all complexes are successfully synthesized from the initial ligands. All complexes were analyzed for their antioxidant properties by DPPH free radical scavenging assay. In addition, the antibacterial effects of the hexane-solved complexes were investigated by disc diffusion method against four Gram positive and negative bacteria. All complexes represented antibacterial activity against bacteria tested especially on Gram positive ones. A theoretical study on the structure, 1H and 31P NMR chemical shifts and the interaction energy between the Pd2+ ion and ligands dppe and ylide Y is also reported. 相似文献