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91.
Walton R. Gutierrez 《Nuclear Physics B》1980,176(1):185-192
We use path integral method for the large-N expansion of the two-dimensional U(N) QCD in the light-cone gauge. We derive the 't Hooft equation for the quark-antiquark bound states from the quadratic part of the expansion. We also derive the effective interactions of the mesons from the higher-order terms of the expansion. 相似文献
92.
Furtado CA Kim UJ Gutierrez HR Pan L Dickey EC Eklund PC 《Journal of the American Chemical Society》2004,126(19):6095-6105
Wet chemical methods involving ultrasound and amide solvents were used to purify and separate large bundles of single-walled carbon nanotubes (SWNTs) into individual nanotubes that could then be transported to silicon or mica substrates. The SWNTs studied were produced by the arc-discharge process. Dry oxidation was used in an initial step to remove amorphous carbon. Subsequently, two acid purification schemes were investigated (HCl- and HNO(3)-reflux) to remove the metal growth catalyst (Ni-Y). Finally, ultrasonic dispersion of isolated tubes into either N,N-dimethylformamide (DMF) or N-methyl-2-pyrrolidone (NMP) was carried out. Raman scattering, atomic force microscopy (AFM), and electron microscopy were used to study the evolution of the products. Raman scattering was used to probe possible wall damage during the chemical processing. We found that both HCl and HNO(3) could be used to successfully remove the Ni-Y below approximately 1 wt %. However, the HNO(3)-reflux produced significant wall damage (that could be reversed by vacuum annealing at 1000 degrees C). In the dispersion step, both amide solvents (DMF and NMP) produced a high degree of isolated tubes in the final product, and no damage during this dispersion step was observed. HNO(3)-refluxed tubes were found to disperse the best into the amide solvents, perhaps because of significant wall functionalization. AFM was used to study the filament diameter and length distributions in the final product, and interesting differences in these distributions were observed, depending on the chemical processing route. 相似文献
93.
Jaime Gutierrez Rosario Rubio Jie-Tai Yu 《Proceedings of the American Mathematical Society》2002,130(8):2237-2246
In this paper we introduce the -resultant of two rational functions and show how it can be used to decide if or if and to find the singularities of the parametric algebraic curve define by . In the course of our work we extend a result about implicitization of polynomial parametric curves to the rational case, which has its own interest.
94.
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96.
Xiomara Gutierrez Felix Silva Manuel Chirinos Javier Leiva Hercilio Rivas 《Journal of Dispersion Science and Technology》2013,34(1-3):405-418
This paper describes the most relevant issues associated with the development of a technology; the formation of highly concentrated bitumen-in-water emulsions. Viscosity values for bitumen-in-water emulsions, containing between 70 and 85% (v/v) of bitumen, have been found to be several order of magnitude lower than the viscosity of the hydrocarbon itself. Thus, these emulsions, have potential applications in the processes of production, transportation, handling and commercialization of these extremely highly viscous hydrocarbons. The emulsions, the properties of which are discussed in this paper, were stabilized with mixtures of nonionic and natural surfactants (1,2) and formed using the HIPR (high internal phase ratio) technique (3). Information on the conditions required to produce emulsions with very narrow droplet diameter distributions is given. Results indicate that the mean droplet diameter, the droplet diameter distribution, and the bitumen volume fraction, significantly modify the rheological behavior. Emulsion stability was measured by following changes in the mean droplet diameter and in the rheological parameters with storage time. 相似文献
97.
Andresen GB Ashkezari MD Baquero-Ruiz M Bertsche W Bowe PD Butler E Cesar CL Chapman S Charlton M Deller A Eriksson S Fajans J Friesen T Fujiwara MC Gill DR Gutierrez A Hangst JS Hardy WN Hayden ME Humphries AJ Hydomako R Jonsell S Madsen N Menary S Nolan P Olin A Povilus A Pusa P Robicheaux F Sarid E Silveira DM So C Storey JW Thompson RI van der Werf DP Wurtele JS Yamazaki Y;ALPHA Collaboration 《Physical review letters》2011,106(14):145001
Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments. 相似文献
98.
Preparation and Characterization of Electrodes Modified with Pyrrole Surfactant,Multiwalled Carbon Nanotubes and Metallophthalocyanines for the Electrochemical Detection of Thiols 下载免费PDF全文
Magdalena Rangel Argote Elizabeth Sánchez Guillén Ana Gabriela Gutiérrez Porras Oracio Serrano Torres Cyrille Richard José H. Zagal Fethi Bedioui Silvia Gutierrez Granados Sophie Griveau 《Electroanalysis》2014,26(3):507-512
Our aim was to prepare hybrid electrodes active towards the electrooxidation of thiols by the co‐immobilization of native carbon nanotubes (CNTs) and cobalt phthalocyanine (CoPc) from aqueous solutions. This strategy was adopted to avoid the oxidation of CNTs that can induce a modification of their exceptional properties. To do so, a hydrosoluble pyrrole surfactant was used to get homogeneous aqueous dispersions of CNTs and CoPc and to trap both materials on the electrode via the electropolymerization of the pyrrole surfactant. The hybrid electrodes exhibit a good electrocatalytic activity towards the oxidation of L ‐cysteine and glutathione. Their performances in terms of limit of detection (0.01 mM) are compatible with the detection of these thiols in biological samples. 相似文献
99.
100.
Eduardo Corts C. Roberto Martinez Martha B. Gutierrez Gomez 《Journal of mass spectrometry : JMS》1991,26(8):695-696
The mass spectra of eight new substituted 2-(p-R2-phenyl)-indole-3-carboxyaldehydes which have potentially useful pharmacological properties, are presented. 相似文献