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991.
992.
Two homologous series of bent-shaped molecules composed of low bent-angle naphthalene central core and long alkoxy tail or alkylthio tail,N(1,7)-n-OPIMB and N(1,7)-n-SPIMB(n = 20,22),respectively,were synthesized.The mesomorphic properties were investigated by differential scanning calorimetry(DSC),polarizing optical microscopy(POM) and X-ray diffraction(XRD). Compared to the direct transition from the isotropic phase to the chiral B4 phase examined in N(1,7)-n-OPIMB,N(1,7)-n-SPIMB exhibited a rare Iso-Ncol-Colh-B4 phase sequence.The combination of the asymmetric low bent-angle 1,7-naphathalene central core and the flexible long alkylthio tail is considered to play an important role in the formation of such a novel phase sequence. 相似文献
993.
994.
Sabine Cantournet Khaled LayouniLucien Laiarinandrasana Roland Piques 《Comptes Rendus Mecanique》2014,342(5):299-310
While natural rubber is commonly considered as an incompressible material, this study shows how carbon black-reinforced natural rubber (NR-CB), when subjected to various mechanical loading conditions (uniaxial, hydrostatic, monotonic, cyclic), is affected by volume change. Experiments show a volume variation even for low straining values and a significant volume change for large elongations. Moreover, volume change can be either reversible or not, depending on the loading conditions. It is related to a competition between void growth, chain orientation, and stress softening. At a microscopic scale, in situ Scanning Electron Microscopy (SEM) examinations and image analysis allow one to record damage and microscopic volume change as a function of elongation. Therefore the volume change measured at the microscopic scale is equal to the macroscopic one. Based on the experimental results, this paper shows that the hypothesis of incompressibility is worth being revisited. Thus, a nearly compressible approach was considered, where the strain energy is assumed to be the sum of spherical and deviatoric parts that are both affected by damage. The model was then implemented in a finite-element code. Good agreement was obtained between experimental results and model predictions for low triaxiality test conditions. 相似文献
995.
Fractional order dynamics and chaotics systems have been recently combined, yielding interesting behaviours. In this paper, a novel integer order hyperchaotic system is considered. Then, a fractional order hyperchaotic representation of said system is proposed using a natural fractionalization. Two different linear control methodologies to deal with the complexity which introduce such systems are proposed. Those methods are able to modify the hyperchaotic behaviour of the system and force it to move towards a fixed point; i.e. steady state. These approaches give a general framework for taming such complex systems using simple linear controllers. The main tools for analysing the controlled system are Matignon stability criterion and RouthHurwitz test. Using a reliable numerical simulation, the designed system is simulated to verify the theoretical analysis. 相似文献
996.
P. Akilan 《Supramolecular chemistry》2013,25(7):495-504
A new series of macrobicyclic ditopic receptors is derived from the precursor compound 3,4:10,11-dibenzo-1,13[N,N′-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}di-aza]-5,9-dioxocyclohexadecane. Using this precursor, mono- and binuclear nickel(II) complexes of type [NiL](ClO4) and [Ni2L](ClO4)2 have been synthesized to undertake electrochemical and catalytic studies on the basis of macrocyclic ring size. The receptor is a tricompartmental macrocycle consisting of ether oxygen, tertiary nitrogen and imine nitrogen atoms. The redox studies of these systems show that the nickel(II) complexes undergo quasi-reversible one-electron reduction and oxidation. All the nickel(II) complexes have square planar geometry and are EPR silent. Examination of the kinetics of the hydrolysis of 4-nitrophenyl phosphate shows that the catalytic activities of the complexes increase with the macrocyclic ring size of the complexes. As the macrocyclic ring size of the complexes increases, the spectral, electrochemical and catalytic studies of the complexes show considerable variation due to distortion in the geometry around the nickel(II) centre. 相似文献
997.
To consider the psychological factors that impact market valuation, a model is formulated for investment behaviour of traders whose decisions are influenced by their trusted peers’ behaviour. The model is implemented and several different “trust networks” are tested. Simulation results demonstrate that real life trust networks can significantly delay the stabilisation of a market. 相似文献
998.
999.
大黄酚在0.15mol/L HAc-NaAc(pH4.9)底液中,出现一灵敏的示波极谱导数峰,峰电位为-0.45V(vs,SCE),峰电流与大黄酚浓度在2.0×10^-7-5.0×10^-6mol/L范围内成线性关系,检测限为2.0×10^-6mol/L。用于生药大黄中大黄酚的测定,回收率为92.4%-108.4%。用多种电化学手段研究体系的电化学行为,测得电极反应电子数n=2。体系具有吸附性,并 相似文献
1000.
ASYMPTOTICBEHAVIOUROFADIFFUSIONSYSTEMWITHTIMEDELAYINPOPULATIONDYNAMICSDingChongwen(丁崇文)(FujianEducationalCollege,福建教育学院,邮编:35?.. 相似文献