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Nonlinear Dynamics - This paper presents an adaptive trajectory tracking controller with full state feedback for vector propulsion unmanned surface vehicle (USV). The controller solves the problem... 相似文献
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《Optik》2014,125(24):7154-7161
Based on the power spectrum of oceanic turbulence proposed by Nikishov, the influence of oceanic optical turbulence on propagation of Gaussian array beams is studied in detail by using five propagation characteristic parameters (i.e., mean-squared beam width, Rayleigh range, turbulence distance, power in the bucket and Strehl ratio). It is shown that the influence of oceanic optical turbulence on propagation of laser beams becomes stronger as τ (ratio of temperature to salinity contribution to the refractive index spectrum) and χT (rate of dissipation of mean-squared temperature) increase and ɛ (rate of dissipation of kinetic energy per unit mass of fluid) decreases, which is in agreement with the further analysis of oceanic turbulence shown in this paper. Furthermore, it is concluded that propagation of laser beams is more affected by oceanic optical turbulence in abyssal region than that in active region or oceanic surface. 相似文献
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Transfer hydrogenation (TH) of ketones and aldehydes was efficiently carried out in 2-propanol at room temperature by means of a ruthenium(II) complex catalyst bearing a 2-(benzoimidazol-2-yl)-6-(pyrazol-1-yl)pyridine ligand. TH of the ketone substrates proceeded in air, reaching final TOFs of up to 59,400 h−1, and the reduction of aldehydes proceeded under a nitrogen atmosphere to achieve final TOFs of up to 5940 h−1. 相似文献
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Mindong Bai Zhitao Zhang Mindi Bai Xiyao Bai Honghui Gao 《Plasma Chemistry and Plasma Processing》2008,28(4):405-414
The synthesis of ammonia has been studied in methane-nitrogen plasmas using a micro-gap discharge under an environmentally friendly condition. The effects of some parameters such as the specific input energy, the discharge gap, the volume ratio of CH4/N2, the residence time, and the gas temperature on the yield of NH3 and conversion rate of CH4 are discussed in the paper. The results show that the highest yield of NH3 is 8000 ppm for a residence time of 1.6 s. In addition, the yield and generating rate of H2 are 9.1% (v/v) and 1879.8 μmol/min, respectively. Therefore, the micro-gap discharge is an efficient method for NH3 synthesis and H2 generation from CH4. 相似文献
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ObjectiveTo explore the disturbed molecular functions and pathways in clear cell renal cell carcinoma (ccRCC) using Gibbs sampling.MethodsGene expression data of ccRCC samples and adjacent non-tumor renal tissues were recruited from public available database. Then, molecular functions of expression changed genes in ccRCC were classed to Gene Ontology (GO) project, and these molecular functions were converted into Markov chains. Markov chain Monte Carlo (MCMC) algorithm was implemented to perform posterior inference and identify probability distributions of molecular functions in Gibbs sampling. Differentially expressed molecular functions were selected under posterior value more than 0.95, and genes with the appeared times in differentially expressed molecular functions ≥5 were defined as pivotal genes. Functional analysis was employed to explore the pathways of pivotal genes and their strongly co-regulated genes.ResultsIn this work, we obtained 396 molecular functions, and 13 of them were differentially expressed. Oxidoreductase activity showed the highest posterior value. Gene composition analysis identified 79 pivotal genes, and survival analysis indicated that these pivotal genes could be used as a strong independent predictor of poor prognosis in patients with ccRCC. Pathway analysis identified one pivotal pathway − oxidative phosphorylation.ConclusionsWe identified the differentially expressed molecular functions and pivotal pathway in ccRCC using Gibbs sampling. The results could be considered as potential signatures for early detection and therapy of ccRCC. 相似文献
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《Solid State Ionics》2006,177(33-34):2865-2872
Metal iodide-doped anhydrous proton conductors in the series xMI2 + (1 − x)(HBS2)3, where M = Ge and Sn, have been prepared. These samples improve upon the anhydrous proton conductivity shown previously in the H2S + B2S3 + GSy series, where G = Si, Ge, and As, through a displacement reaction to incorporate HI into the materials. This is analogous to doping a silver halide salt into fast ion conducting chalcogenide glasses, such as AgI + Ag2S + B2S3 + SiS2, which results in a one to two orders of magnitude improvement in the ionic conductivity. The structural modification of the boroxol ring units in the thioboric acid is discussed based on the infrared and Raman spectroscopy. The DC conductivity, estimated from AC impedance spectra, of the metal iodide-doped (HBS2)3 samples is reported as a function of temperature and related back to the underlying structural chemistry of these materials. The static solid state proton NMR spectra were also used to identify the proton environment and proton dynamics. These materials represent an improvement upon previous anhydrous proton-conducting materials and represent an important step in finding intermediate temperature proton conductors. 相似文献
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《Tetrahedron: Asymmetry》2005,16(9):1681-1684
Racemic 4,5-bis-(2-hydroxy-phenyl)-benzo[f]isoindole-1,3-dione 2, an atropisomeric diphenol prone to thermal isomerisation, has been efficiently resolved by conversion into its N-(α)-Boc-tryptophan diesters. Easy chromatographic separation of the diastereomeric pair of diesters, followed by ester cleavage under mild conditions gave each enantiomer in good yield and high enantiomeric purity. X-ray diffraction on a single crystal of one of the diastereomeric diesters allowed attribution of the absolute configuration of the stereogenic axes. 相似文献
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The present work deals with intensification of depolymerization of polyacrylamide (PAM) solution using hydrodynamic cavitation (HC) reactors based on a combination with hydrogen peroxide (H2O2), ozone (O3) and ultraviolet (UV) irradiation. Effect of inlet pressure in hydrodynamic cavitation reactor and power dissipation in the case of UV irradiation on the extent of viscosity reduction has been investigated. The combined approaches such as HC + UV, HC + O3, HC + H2O2, UV + H2O2 and UV + O3 have been subsequently investigated and found to be more efficient as compared to individual approaches. For the approach based on HC + UV + H2O2, the extent of viscosity reduction under the optimized conditions of HC (3 bar inlet pressure) + UV (8 W power) + H2O2 (0.2% loading) was 97.27% in 180 min whereas individual operations of HC (3 bar inlet pressure) and UV (8 W power) resulted in about 35.38% and 40.83% intrinsic viscosity reduction in 180 min respectively. In the case of HC (3 bar inlet pressure) + UV (8 W power) + ozone (400 mg/h flow rate) approach, the extent of viscosity reduction was 89.06% whereas individual processes of only ozone (400 mg/h flow rate), ozone (400 mg/h flow rate) + HC (3 bar inlet pressure) and ozone (400 mg/h flow rate) + UV (8 W power) resulted in lower extent of viscosity reduction as 50.34%, 60.65% and 75.31% respectively. The chemical structure of the treated PAM by all approaches was also characterized using FTIR (Fourier transform infrared) spectra and it was established that no significant chemical structure changes were obtained during the treatment. Overall, it can be said that the combination of HC + UV + H2O2 is an efficient approach for the depolymerization of PAM solution. 相似文献
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