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121.
Bruins EE Bauer TS den Bok HW Duif CP van Hoek WC de Lange DJ Misiejuk A Papandreou Z Sichtermann EP Tjon JA Willering HW Yeomans DM Reike H Durek D Frommberger F Gothe R Jakob D Kranefeld G Kunz C Leiendecker N Pfeiffer G Putsch H Reichelt T Schoch B Wacker D Wehrmeister D Wilhelm M Jans E Konijn J de Vries R Furget C Voutier E Arenhövel H 《Physical review letters》1995,75(1):21-24
122.
We stabilize unstable periodic orbits of a fast diode resonator driven at 10.1 MHz (corresponding to a drive period under 100 ns) using extended time-delay autosynchronization. Stabilization is achieved by feedback of an error signal that is proportional to the difference between the value of a state variable and an infinite series of values of the state variable delayed in time by integral multiples of the period of the orbit. The technique is easy to implement electronically and it has an all-optical counterpart that may be useful for stabilizing the dynamics of fast chaotic lasers. We show that increasing the weights given to temporally distant states enlarges the domain of control and reduces the sensitivity of the domain of control on the propagation delays in the feedback loop. We determine the average time to obtain control as a function of the feedback gain and identify the mechanisms that destabilize the system at the boundaries of the domain of control. A theoretical stability analysis of a model of the diode resonator in the presence of time-delay feedback is in good agreement with the experimental results for the size and shape of the domain of control. (c) 1997 American Institute of Physics. 相似文献
123.
124.
Starting from the readily available 2-aminobenzhydrols ( 7 ), 3-amino-1,2,4-benzotriazine ( 11 ) and 2-amino-3-pyridinol ( 12 ), novel derivatives of 5-phenyl-5H-imidazo[1,2-a][3,1]benzothiazine-2-carboxylic acid, ethyl ester ( 4 ), imidazo[2,1-c][1,2,4]benzotriazine-2-carboxylic acid, ethyl ester ( 5 ) and 4H-imidazo[2,3-c]pyrido-[2,3-e][1,4]oxazine ( 6 ) were prepared. 相似文献
125.
High-resolution spectra of the NO2 continuum emission produced from the reaction NO + O3 → NO2 + O2 have been investigated to detect any possible emission from O2(1Δg) at 1270 nm or O2(1Σ+g) at 762 nm. The photolysis of O3/O2 mixtures at 253.7 nm, which produces both states of O2 with known quantum efficiency, has been used as an internal standard. From the results it is concluded that less than 1/300 and 1/200 of the NO + O3 reactive collissions result in production of O2(1Δg) or O2(1Σ+g), respectively, at room temperature. 相似文献
126.
127.
The C-13 isotopic selectivity in the multiphoton decomposition of CF3Br has been shown to increase with increasing pressure of substrate for photolysis far to the red of the resonant, low intensity absorption band using relatively low fluence radiation. However, the quantum efficiency would appear to decrease as pressure is increased. 相似文献
128.
The effect of organic modifier concentration on retention and selectivity of two piperazine diastereomers in a typical n-octadecyl-bonded silica (ODS) column was investigated at pH 6.4 and pH 3.0 using phosphate-buffered acetonitrile (MeCN/H2O) and methanol (MeOH/H2O) mobile phases. The results show the logarithmic retention factors decrease with increasing organic concentration in a less rectilinear fashion in the MeCN/H2O system than in the MeOH/H2O system at high organic concentrations at both pHs. At pH 6.4, the MeOH/H2O system provided significantly higher diastereomer selectivity than the MeCN/H2O system, which can be ascribed to the hydrogen bonding interaction of methanol (as a hydrogen donor) with the piperazine amine moiety of the solute (as a hydrogen acceptor). At pH 3.0, both mobile phases provided high selectivity, in which both acetonitrile and methanol acted as hydrogen acceptors, while the protonated amine acted as the hydrogen donor. The effect of temperature on retention and selectivity was also studied in the two mobile phase systems at both pHs. It was found that at pH 6.4 the retention and selectivity were enthalpically driven in the MeOH/H2O system, while entropically driven in the MeCN/H2O system. However, the retention was entropically driven and the selectivity enthalpically driven in both systems at pH 3.0. Locally preferential solvating and hydrogen bonding effects are proposed to explain the anomalous retention and selectivity behaviors. 相似文献
129.
Dehonor M Masenelli-Varlot K González-Montiel A Gauthier C Cavaillé JY Terrones H Terrones M 《Chemical communications (Cambridge, England)》2005,(42):5349-5351
Polymer brushes consisting of polystyrene (PS) chains bonded covalently to N-doped multiwalled carbon nanotubes (CNx) were synthesized by a "grafting from" route using nitroxide mediated radical polymerization (NMRP). 相似文献
130.