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排序方式: 共有296条查询结果,搜索用时 46 毫秒
1.
Peralta Cecilia Mariana Acosta Gimena Henestrosa Cecilia Gil Raúl Andrés Fernández Liliana Patricia 《Journal of Analytical Chemistry》2022,77(3):308-317
Journal of Analytical Chemistry - The present development involved a flow injection strategy using a mini-column of multiwalled carbon nanotubes and fluorescent detection (λex of 283 nm,... 相似文献
2.
Natural circulation of water in a tilted square loop of circular cross-section is studied in this paper. Heating is by an electrical resistance and cooling through a heat exchanger. Heating and cooling are at opposite sides of the square loop. The natural convection flow is determined experimentally as a function of the heating flux and the tilt angle. Multiplicity of steady-state velocities is experimentally confirmed.
Nomenclature Q input heat flow - V fluid velocity - V m maximum fluid velocity - tilt angle - c critical tilt angle - T temperature difference 相似文献
Einphasiger Naturumlauf in einem geneigten quadratischen Loop
Zusammenfassung In dem Aufsatz wird der Naturumlauf von Wasser in einem geneigten quadratischen Loop mit Rohren kreisförmigen Querschnittes behandelt. Die Beheizung erfolgt über einen elektrischen Widerstand und die Kühlung über einen Wärmetauscher. Heizung und Kühlung sind auf den gegenüberliegenden Seiten des quadratischen Loops angeordnet. Der Naturumlauf wird experimentell als Funktion des Wärmestromes und des Neigungswinkels bestimmt. Es wird die Vielfältigkeit von stationären Geschwindigkeiten experimentell bestätigt.
Nomenclature Q input heat flow - V fluid velocity - V m maximum fluid velocity - tilt angle - c critical tilt angle - T temperature difference 相似文献
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J. Nogueira A. Lecuona P. A. Rodríguez J. A. Alfaro A. Acosta 《Experiments in fluids》2005,39(2):314-321
Elsewhere in this volume (Nogueira et al. (2005) Exp Fluids, in press), the conceptual background that explains the possibility of resolving wavelengths smaller than the size of the interrogation window, with no basic restrictions but sampling, has been explained. Here, a practical implementation of the concepts is performed. To achieve this resolution in iterative PIV processing, an appropriate weighting function can be used, as commented in that reference. Here, the constraints for the design of such weighting functions are presented and analysed. This opens a line of work on possible weighting functions to develop, since the weightings used in these iterative methods, like local field correction particle image velocimetry (LFC-PIV) (Nogueira et al. (1999) Exp Fluids 27(2):107–116), have not been optimised yet. As an example, different weighting functions are commented and tested both on synthetic and real images. The results on these new weightings indicate that the current ones can be improved and the optimisation criteria are open for further advancement. 相似文献
6.
Paola Acosta Braulio Insuasty Rodrigo Abonia Margarita Gutierrez Jairo Quiroga 《Molecular diversity》2017,21(4):943-955
An efficient route for the synthesis of novel 7-aryl and 7-spiropyrazolo[4\(^{\prime }\),3\(^{\prime }\):5,6]pyrido[2,3-d]pyrimidine derivatives is described. These compounds were obtained by a cyclocondensation reaction between pyrazolopyridinediamines 4 and aldehydes 5 or cyclic ketones 6 in the presence of acetic acid as catalyst. This procedure provides the desired compounds in good yields under a simple two-step methodology. The obtained compounds were evaluated as AChE inhibitors and showed weak AChe inhibition with \(\hbox {IC}_{50} = 115{-}470 \, \upmu \hbox {M}\). 相似文献
7.
J. Guillermo Soriano‐Moro Julio C. Rico‐Valverde Francisco J. Enriquez‐Medrano Hortensia Maldonado‐Textle Eduardo Vivaldo‐Lima Ricardo Acosta‐Ortiz Ramiro Guerrero‐Santos 《Macromolecular rapid communications》2008,29(1):80-85
In this communication, γ‐phenyl‐γ‐butyrodithiolactone (DTL1) is presented as the first example of a new type of control agent. The styrene polymerization carried out at 60 °C in the presence of DTL1 exhibits living characteristics, without consuming DTL1 during the process. This unprecedented behavior was explained by a mechanism based on the reversible formation of a persistent radical adduct between the DTL1 and the polystyrene macroradicals.
8.
Eleonora Erdmann Marcos L. Dias Victor J. R. R. Pita Hugo Destéfanis Fernanda Monasterio Delicia Acosta 《Macromolecular Symposia》2007,258(1):82-89
Summary: Preparation and morphology of high density polyethylene (HDPE)/ polyamide 6 (PA 6)/modified clay nanocomposites were studied. The ability of PA 6 in dispersing clays was used to prepare modified delaminated clays, which were then mixed with HDPE. Mixing was performed using melt processing in a torque rheometer equipped with roller rotors. After etching the materials with boiling toluene and formic acid at room temperature, the morphology was examined by SEM analyses, showing that the PA 6 formed the continuous phase and HDPE the dispersed phase. X-ray diffraction patterns show that the (001) peak of the clay is dramatically decreased and shifted to lower angles, indicating that intercalated/exfoliated nanocomposites are obtained. TEM analyses confirmed the typical structure of exfoliated nanocomposites. A scheme for the mechanism of exfoliation and/or intercalation of these HDPE /PA 6/ /organoclay nanocomposites is proposed. 相似文献
9.
Summary The surface properties of sepiolite were investigated by inverse gas chromatography. It is shown that the value of the dispersive component change uniformly with temperature, while the values obtained for the parameters KA and KD indicate an acidic character for the sepiolite surface. 相似文献
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