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71.
This paper studies the sampled-data control problem for a class of high-order nonlinear systems. Based on exact discrete-time equivalent model of the sampled-data system, a multi-rate sampled-data controller with the form of a power series expansion is designed to achieve the global asymptotic stability of the closed-loop system under some assumptions. Approximate solutions of the proposed controller are proved to be effective by a theoretical analysis. The results show that, compared with the emulated control scheme, the approximate controllers allow considering larger sampling periods and enlarge the domain of attraction for a given sampling period. Finally, a simulation example is given to show the effectiveness of the proposed control scheme. 相似文献
72.
Yaoxiao Zhao Weixing Chen Mengyang Li Kun Yuan Meng An 《International journal of quantum chemistry》2024,124(1):e27269
The search for good nonlinear optical (NLO) materials is of utmost importance in laser technology and optical information science, making it a popular research topic in materials science. It is reported that the introduction of alkali metal Li can enhance the NLO properties of nanocarbon materials. Here, metal Al, which exhibits similar electron transfer characteristics to Li, was used for the first time to enhance the NLO properties of nanocarbon cluster C60, which possesses a large delocalized π structure and the highest yield in the fullerene family. Density functional theory calculations in combination with Boltzmann distribution showed that the most thermodynamically stable Al@Ih(1812)-C60 exhibited good second-order NLO properties, which originated from the noncentrosymmetry geometry and one extra delocalized electron on Ih(1812)-C60 from the 3p shell of inner Al. Density of state analysis indicated that the molecular orbitals of Al@Ih(1812)-C60 were primarily formed by Ih(1812)-C60 with minimal Al participation, and the presence of Al always resulted in an antibonding orbital effect. Bond critical point and electron localization function analyses indicated almost no covalent interaction between Al and Ih(1812)-C60. Exohedral functionalization was employed to further stabilize Al@Ih(1812)-C60 with radical character, and the infrared spectrum was also analyzed in detail. This study has promising implications for expanding the potential applications of fullerenes in optical devices. 相似文献
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《Fluid Phase Equilibria》1999,155(2):277-286
An experimental apparatus was built for measuring the gas solubility at high temperature and pressure. An auxiliary system was developed to keep the system pressure constant while the liquid samples are withdrawn. Solubility of methane, carbon dioxide and nitrogen in ethylene glycol (EG) was determined experimentally at temperatures of 323.15, 373.15 and 398.15 K and pressures up to 40 MPa. SRK equation of state was used to calculate the phase equilibria for those polar asymmetric systems. 相似文献
75.
Isospin Effects in the Isospin Fractionation Process in Intermediate Energy HeavyIon Collisions 下载免费PDF全文
Based on the isospin dependent quantum molecular dynamics model we investigated the isospin effects of isospin fractionation (N/Z)gas/(N/Z)liq from the neutron-proton ratio of colliding system and impact parameter. Here (N/Z)gasand (N/Z)liq is the neutron-proton ratio of nucleon emission for gas phase and that of fragment emission for liquid phase, respectively. Our results show that the (N/Z)gas/(N/Z)liq increases with the neutron-proton ratio of colliding systems when the system mass, incident energy and impact parameters are fixed. For the neutron-rich systems, the (N/Z)gas/(N/Z)liq depends sensitively to the form of symmetry potential and weakly on the isospin effect of the in-medium nucleon-nucleon cross section; For the neutron-poor colliding system, however, the (N/Z)gas/(N/Z)liq is not sensitive to both the form of symmetry potential and the isospin effect of the in-medium nucleon-nucleon cross section. We also found that the dependence of (N/Z)gas/(N/Z)liq on the impact parameter is not obvious. Detailed discussion and explanation for leading to these results are presented in the paper. According to these results, we propose that (N/Z)gas/(N/Z)liq can be directly compared with the experimental data to get the information about symmetry potential. 相似文献
76.
《Comptes Rendus de l'Academie des Sciences Series IIA Earth and Planetary Science》1998,326(3):317-322
We obtain a sufficient condition of blow-up and the blow-up set of the solution of a semilinear parabolic equation of second order with non-linear boundary conditions. We also give a sufficient condition for the solution of the same equation to tend to zero, and his asymptotic behaviour. 相似文献
77.
在DFT-B3LYP/6-311++G**水平上分别求得(CH3)2S…ClOH卤键复合物和(CH3)2S…HOCl氢键复合物势能面上的稳定构型. 频率分析表明, 与单体HOCl相比, 在两种复合物中, 10Cl—11O和12H—11O键伸缩振动频率发生显著的红移. 经MP2/6-311++G**水平计算的含基组重叠误差(BSSE)校正的气相中相互作用能分别为-11.69和-24.16 kJ·mol-1. 自然键轨道理论(NBO)分析表明, 在(CH3)2S…ClOH卤键复合物中, 引起10Cl—11O键变长的因素包括两种电荷转移: (i) 孤对电子LP(1S)1→σ*(10Cl—11O); (ii) 孤对电子LP(1S)2→σ*(10Cl—11O), 其中孤对电子LP(1S)2→σ*(10Cl—11O)转移占主要作用, 总的结果是使σ*(10Cl—11O)的自然布居数增加0.14035e, 同时11O原子的再杂化使其与10Cl成键时s成分增加, 即具有与电荷转移作用同样的“拉长效应”; 在(CH3)2S…HOCl氢键复合物中也存在类似的电荷转移, 但是11O原子的再杂化不同于前者. 自然键共振理论(NRT)进行键序分析表明, 在卤键复合物和氢键复合物中, 10Cl—11O和12H—11O键的键序都减小. 通过分子中原子理论(AIM)分析了复合物中卤键和氢键的电子密度拓扑性质. 相似文献
78.
Nitric oxide reduction to ammonia by electrocatalysis is the potential application in the elimination of smog and energy conversion. In this work, the feasibility of the application of two-dimensional metal borides(MBenes) in nitric oxide electroreduction reaction(NOER) was investigated through density functional theory calculations. Including the geometry and electronic structure of five kinds of MBenes, the adsorption of NO on the surface of these substrates, the selective adsorption of hydrog... 相似文献
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