排序方式: 共有12条查询结果,搜索用时 156 毫秒
1.
Corella Puertas Elena Dzafic Adna Coulombe Sylvain 《Plasma Chemistry and Plasma Processing》2020,40(1):145-167
Plasma Chemistry and Plasma Processing - Although the erosion of high-voltage electrodes was extensively studied in in-liquid electrical discharges, to the best of our knowledge, the erosion... 相似文献
2.
Martin-del-Campo Jennifer Coulombe Sylvain Kopyscinski Jan 《Plasma Chemistry and Plasma Processing》2020,40(4):857-881
Plasma Chemistry and Plasma Processing - The environmental impact of greenhouse gases such as carbon dioxide and methane can be reduced if they are used as feedstock to synthesize chemical building... 相似文献
3.
J Sygusch R Coulombe J M Cassanto M G Sportiello P Todd 《Journal of Crystal Growth》1996,162(3-4):167-172
Two-step crystallization experiments were conducted in low gravity employing a liquid-liquid diffusion method in an effort to eliminate problems associated with protein crystal growth under the supersaturating conditions required for nucleation. Experiments were performed in diffusion cells formed by the sliding of blocks on orbit. Step gradient diffusion experiments consisted of first exposing protein solutions in diffusion half-wells for brief periods to initiating buffer solutions of high precipitant concentrations to induce nucleation followed by expoure of the same protein solutions to solutions of lower precepitant concentration to promote growth of induced nuclei into crystals. To avoid convective disturbances that occur when solutions of discrepant densities are interfaced at normal gravity, crystallization of hen egg-white lysozyme and rabbit skeletal muscle aldolase by step gradient diffusion was investigated in low gravity on four NASA space shuttle flights. In general, the largest ctystals of both proteins formed at the highest initiating precipitant concentration used, which is consistent with nuclei formation upon brief exposure to high precipitant concentration, and that these nuclei are competent for sustained growth at lower precipitant concentration. The two-step approach dissociates nucleation events from crystal growth allowing parameters affecting nucleation kinetics such as time, precipitant concentration and temperature of nucleation to be varied separately from conditions used for post-nucleation growth. 相似文献
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5.
Marc-André Coulombe Martin Lebeuf Neal Fairley John Walton Gervais Soucy 《Journal of Electron Spectroscopy and Related Phenomena》2012
Aluminium carbide formation and subsequent dissolution is a generally accepted mechanism to explain the cathode wear in the Hall-Héroult industry. Carbide formation is thought to occur inside the cathode pores. Being dependent upon cathodic current density, it is believed to be an electrochemical process. It is also associated with the presence of cryolitic bath species involved in the dissolution of the carbide layer and thus enabling further carbide formation. 相似文献
6.
Leron Vandsburger Edward J. Swanson Jason Tavares Jean-Luc Meunier Sylvain Coulombe 《Journal of nanoparticle research》2009,11(7):1817-1822
This article reports a method for surface modification of multi-walled carbon nanotubes (MWNTs) using a low-pressure capacitively
coupled RF glow-discharge. Ar/C2H6 and Ar/C2H6/O2 gaseous mixtures were used to produce non-polar (np-) and polar (p-) coatings, respectively, onto MWNTs. After 5 min of plasma
treatment at 20 W and 20 torr, strongly hydrophobic and non-electrically conductive np-MWNTs were produced. The p-MWNTs were
strongly hydrophilic and showed no measurable hydrophobic recovery 2 weeks after treatment. Aqueous suspensions of p-MWNTs
remained stable and free of agglomerates after being boiled. The ζ-potential of p-MWNT nanofluids was −40.3 mV, indicating
a highly stable dispersion. 相似文献
7.
Coulombe S. Meunier J.L. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(5):913-918
The importance of having high local cathode spot pressures for the self-sustaining operation of a thermal arc plasma on a cold cathode is theoretically investigated. Applying a cathode sheath model to a Cu cathode, it is shown that cathode spot plasma pressures ranging 7.4-9.2 atm and 34.2-50 atm for electron temperatures of ~1 eV are needed to account for current densities of 109 and 1010 A·m-2, respectively. The study of the different contributions from the ions, the emission electrons, and the back-diffusing plasma electrons to the total current and heat transfer to the cathode spot has allowed us to show the following. 1) Due to the high metallic plasma densities, a strong heating of the cathode occurs and an important surface electric field is established at the cathode surface causing strong thermo-field emission of electrons. 2) Due to the presence of a high density of ions in the cathode vicinity, an important fraction of the total current is carried by the ions and the electron emission is enhanced. 3) The total current is only slightly reduced by the presence of back-diffusing plasma electrons in the cathode sheath. For a current density jtot=109 A·m-2 , the current to the cathode surface is mainly transported by the ions (76-91% of jtot while for a current density jtot = 1010 A·m-2, the thermo-field electrons become the main current carriers (61-72% of jtot). It is shown that the cathode spot plasma parameters are those of a high pressure metallic gas where deviations from the ideal gas law and important lowering of the ionization potentials are observed 相似文献
8.
C. O'Neill B. Coulombe P. Galarneau M.-M. Denariez-Roberge 《Applied physics. B, Lasers and optics》1990,51(2):116-120
Nondegenerate four-wave mixing has been performed in DDI-methanol solutions using ruby laser as writing beams. The reading beam was either a pulsed one at 538.8 nm or a continuous one at 632.8 nm. Contributions from both saturation and thermal gratings were separated temporally and evaluated. 相似文献
9.
LaPlante SR Gillard JR Jakalian A Aubry N Coulombe R Brochu C Tsantrizos YS Poirier M Kukolj G Beaulieu PL 《Journal of the American Chemical Society》2010,132(43):15204-15212
Significant advances have led to receptor induced-fit and conformational selection models for describing bimolecular recognition, but a more comprehensive view must evolve to also include ligand shape and conformational changes. Here, we describe an example where a ligand's "structural hinge" influences potency by inducing an "L-shape" bioactive conformation, and due to its solvent exposure in the complex, reasonable conformation-activity-relationships can be qualitatively attributed. From a ligand design perspective, this feature was exploited by successful linker hopping to an alternate "structural hinge" that led to a new and promising chemical series which matched the ligand bioactive conformation and the pocket bioactive space. Using a combination of X-ray crystallography, NMR and modeling with support from binding-site resistance mutant studies and photoaffinity labeling experiments, we were able to derive inhibitor-polymerase complexes for various chemical series. 相似文献
10.
M.H. Abdallah S. Coulombe J.M. Mermet J. Hubert 《Spectrochimica Acta Part B: Atomic Spectroscopy》1982,37(7):583-592
A new microwave plasma at atmospheric pressure is described. The plasma is supported by a surface wave excitation structure called “surfatron”. Both argon and helium can be used to sustain the plasma. In this study, helium has been selected. The sample introduction system consists of an ultrasonic nebulizer associated with a dcsolvation system. The analytical performance in terms of detection limits, calibration curves and some interferences have been assessed. Because of the relatively low power and the short residence time the main problem seems to be the atomization process. 相似文献