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11.
Abdallah R Meille V Shaw J Wenn D de Bellefon C 《Chemical communications (Cambridge, England)》2004,(4):372-373
A microstructured mesh contactor that can offer residence time of more than minutes is used for gas-liquid-solid hydrogenations and gas-liquid asymmetric hydrogenations. Applications for catalyst/chiral inductor screening and for kinetic data acquisition are demonstrated. 相似文献
12.
Ahmed E. Radwan 《Il Nuovo Cimento D》1987,9(10):1233-1243
Summary The capillary instability of an annular liquid jet surrounding a solid cylinder is presented. A general dispersion equation
is derived based on the linear-perturbation technique. The instability as well as stability characteristics of that model
are identified analytically and confirmed numerically. The model is unstable only to the axisymmetric perturbation whose wavelengths
are longer than the circumference of the liquid jet, while it is stable to all other perturbations. The maximum temporal amplification
values prevailing on such a model are fairly lower than those of the full liquid jet. The thicker the solid cylinder, whether
it is regular or irregular, the larger is its stabilizing effect.
Riassunto Si presenta l’instabilità capillare di un getto anulare di liquido che circonda un cilindro solido. Si deduce un’equazione generale di dispersione basata sulla tecnica di perturbazione lineare. Le caratteristiche d’instabilità cosí come quelle di stabilità di quel modello si identificano analiticamente e sono confermate numericamente. Il modello è instabile solo rispetto alla perturbazione assisimmetrica, le cui lunghezze d’onda sono piú lunghe della circonferenza del getto di liquido, mentre è stabile rispetto a tutte le altre perturbazioni. I valori massimi dell’amplificazione temporale che prevalgono in tale modello sono molto piú bassi di quelli del pieno flusso di liquido. Piú spesso è il cilindro solido sia esso regolare o irregolare, maggiore il suo effetto stabilizzante.
Резюме Анализируется капиллярная неустойчивость кольцевой жидкой струи. окружающей твердьй цилиндр. Выводится общее дисперсионное уравнение. основанное на линейной пертурбационной технике. Неустойчивость, а также характеристики устойчивости в этой модели определяются аналитически и подтверждаются численно. Предложенная модель оказывается неустойчнвой только для осесимметричных возмушений, длины волн которых превышают окружность жидкой струи, и является устойчивой для всех других возмущений. Максимальные значения временного увеличения в такой модели оказываются довольно низкими. Стабилизирующий эффект увеличивается с толщиной твердого цилиндра.相似文献
13.
The consecutive k-out-of-r-from-n: F system was generalized to multi-state case. This system consists of n linearly ordered components which are at state below j if and only if at least kj components out of any r consecutive are in state below j. In this paper we suggest bounds of increasing multi-state consecutive-k-out-of-r-from-n: F system (k1 ? k2 ? ? ? kM) by applying second order Boole–Bonferroni bounds and applying Hunter–Worsley upper bound. Also numerical results are given. The programs in V.B.6 of the algorithms are available upon request from the authors. 相似文献
14.
The samples Mg1+xTixFe2−2xO4 were prepared in a single phase spinel structure as indicated from X-ray analysis. The preference of Mg2+ ions to the octahedral site decreases the ratio of the normal spinel in the investigated ferrite where the Mg2+ increases on the expense of the Fe3+ ions on the same site. The increase in the conductivity was found to be due to thermally activated mobility of charge carriers. The mobility data enhances the use of Verway model of conductivity which depends on the electron exchange between iron ions of different valences located on the same crystallographic sites. The existence of Ti4+ ions on the octahedral site screens the polarization and decreases the conductivity of the samples. Peculiar behavior was obtained for Ti content of 0.7 and 0.8 due to the presence of secondary phases. 相似文献
15.
J. Michalik J. Kominek Z. Bazaniak M. Radwan 《Isotopes in environmental and health studies》2013,49(4):132-138
Es werden Methoden und Ergebnisse der Untersuchung der Schwefelbilanz beim Krupp-Rennverfahren und beim Siemens- Martin-Prozeβ unter Verwendung von 35S beschrieben. Die Markierungsverfahren für die Ausgangsstoffe werden angegeben. 相似文献
16.
17.
18.
M.A. Zaitoun T. Kim K. Momani A.K. El-Qisairi N.E. Radwan 《Journal of luminescence》2008,128(2):227-231
The Lanthanide complexes Eu-2.2.1 and Eu-2.2.2 were synthesized and then incorporated into silica based transparent organic-inorganic hybrid material by the sol-gel method as an example of how doped xerogel materials are emerging as an important means of producing new materials. The produced gels were diagnosed to monitor emission spectra of the luminescent trivalent europium (Eu3+) complexes; emissions were compared to those for gels containing uncomplexed Eu3+. Results of the experiments (emission and lifetimes) concerning the coordination sphere composition showed that a cryptand ligand with aromatic groups (short range effect) and the hydrophobic gel host (long range effect) settle efficient action in the antenna effect and isolate the central ion from efficient quenchers, as e.g. water molecules. Each ligand imposed a distinct splitting pattern on the europium emission bands that helps identify them. 相似文献
19.
1‐Morpholin‐4‐yl‐5,6,7,8‐tetrahydroisoquinoline‐4‐carbonitrile ( 2 ) was synthesized from 3‐amino‐1‐thioxo‐5,6,7,8‐tetrahydro‐1H‐isothiochromene‐4‐carbonitrile ( 1 ) and used as starting material to synthesize many thienotetrahydroisoquinolines ( 4 ), which in turn were used in the synthesis of many pyrimidothienotetrahydroisoquinolines. 相似文献
20.
The effect of furfural benzoylhydrazone and its derivatives (I-VII) as corrosion inhibitors for C-steel in 1M phosphoric acid solution has been studied by weight-loss and galvanostatic polarization techniques. A significant decrease in the corrosion rate of C-steel was observed in the presence of the investigated inhibitors. This study revealed that, the inhibition efficiency increases with increasing the inhibitor concentration, and the addition of iodide ions enhances it to a considerable extent. The effect of temperature on the inhibition efficiency of these compounds was studied using weight-loss method. Activation energy (E(a)*) and other thermodynamic parameters for the corrosion process were calculated and discussed. The galvanostatic polarization data indicated that, the inhibitors were of mixed-type, but the cathode is more polarized than the anode. The adsorption of these compounds on C-steel surface has been found to obey Frumkin's adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the undertaken inhibitors. 相似文献