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K. T. A. L. Burm 《等离子体物理论文集》2005,45(1):54-60
Optical emission spectroscopy is an optical non‐destructive method with which the temperature of the heavy particles (atoms, molecules, and ions) and the vibration temperature is determined in an air plasma torch and in an atmospheric nitrogen dielectric barrier parallel plate discharge. The two temperatures are measured to obtain an estimation of the deviation from local thermal equilibrium and to compare the two plasma source configurations which are used for surface treatment. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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[reaction: see text] Solvolyses of methyl and ethyl chloroglyoxylates proceed about 10(6) times faster than the identical solvolyses of the corresponding chloroformates. The correlation parameters obtained from application of the extended Grunwald-Winstein equation are consistent with an addition-elimination (association-dissociation) mechanism over the full range of solvents, with the addition step being rate determining. 相似文献
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Jin Burm Kyong Chan Joo Rhu Yong‐Gun Kim Dennis N. Kevill 《Journal of Physical Organic Chemistry》2007,20(7):525-531
The specific rates of solvolysis of 2‐adamantyl fluoroformate have been measured at 25.0 °C in 20 pure and binary solvents. These are well correlated using the extended Grunwald–Winstein equation, with incorporation of the NT solvent nucleophilicity scale and the YCl solvent ionizing power scale. The sensitivities (l = 2.15 ± 0.17 and m = 0.95 ± 0.07) toward the changes in solvent nucleophilicity and solvent ionizing power, and the kF/kCl values are very similar to those previously observed for solvolyses of n‐octyl fluoroformate, consistent with the addition step of an addition‐elimination pathway being rate‐determining. For aqueous ethanol, measurement of the product ratio allowed selectivity values (S) to be determined. The results are compared with those reported earlier for 2‐adamantyl chloroformate and mechanistic conclusions are drawn. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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K. T. A. L. Burm 《Plasma Chemistry and Plasma Processing》2012,32(2):401-407
The plasma state is frequently referred to as the fourth state of matter in the sequence: solid, liquid, gas, and plasma.
The statement implies that plasma is another phase. Each state is achieved by adding heat to the previous state. The first
three states are the three common phases achieved via phase transitions. The statement that plasmas are the fourth state of
matter is examined considering phase transitions. It is shown that the transition from gas to plasma is not a phase transition
similar to the other phase transitions at which transitions the differential of the Gibbs free energy equals zero. Therefore,
strictly speaking, plasmas are better not called the fourth state of matter. 相似文献
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To describe plasmas in non-local thermal equilibrium (non-LTE) four parameters need to be used, which are usually besides the pressure and the electron temperature, the electron density and the atom temperature. In the approach presented here it is argued that the use of four other variables is preferable. These four parameters are the total pressure, the ratio of the electron density and the squares root of the total pressure, and two specific non-equilibrium parameters. The non-equilibrium parameters are chosen such that they describe deviations from ionization–recombination equilibrium, and deviations from temperature equilibrium.It appears that the influence of deviations from complete LTE on the transport coefficients is often small when the parameters are scaled with the electron density and the pressure. In this way, the non-LTE transport properties can be estimated by using complete LTE transport coefficients without losing much accuracy. 相似文献
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Ping Jiang Demetre J. Economou Chee Burm Shin 《Plasma Chemistry and Plasma Processing》1995,15(3):383-396
The effect of power modulation oil radical concentration and uniformity in a single-wafer plasma reactor was investigated with a radical transport and reaction model. Plasma etching of silicon using tetrafluoromethane under relatively high pressure (l torr) high frequency (13.56 MHz) conditions was taken as an example system. Gas velocity, temperature, and radical concentration profiles were obtained numerically by a finite element method. When compared to a contin uous wave plasma, power modulation can alter the relative concentration of radicals and in turn the each rate and uniformity as well as selectivity and anisotropy Uniformity is improved by power modulation except at high flow rates which, however, result in poor utilization of the feedstock gas. 相似文献
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Rapid and highly sensitive trace analysis of cyanide water pollutant in an alligator teeth-shaped PDMS microfluidic channel was investigated using surface-enhanced Raman spectroscopy. Compared with previously reported analytical methods, the detection sensitivity was enhanced by several orders of magnitude. 相似文献