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1.
Ultramicroscopy ; 96(1): 105-16, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12623175

RESUMEN

To determine long-range order parameters from electron diffraction intensities, the authors have developed a CCD camera system to detect precisely electron diffraction intensities, a method for quickly and precisely measuring specimen thickness, and a computer programming to calculate long-range order parameters from the ratio of superlattice and fundamental diffraction intensities. Thickness variation over a diffraction area is taken into consideration in the calculation of electron diffraction intensities on the basis of the multi-slice method, and long-range order parameters are calculated by the successive approximation method. The absorptive form factors are also calculated from experimental data of diffraction intensities by parameter fitting, and the effect of absorption on the calculation of long-range order parameters is examined. The values of Cu(3)Au alloys aged at 523 and 653 K that were obtained by averaging long-range order parameters determined for several diffraction areas with the developed method are close to the reported data obtained by the X-ray diffraction method. The main causes for the deviation of long-range order parameters determined for several diffraction areas are also discussed.


Asunto(s)
Microscopía Electrónica/métodos , Algoritmos , Cobre/química , Cámaras gamma , Aleaciones de Oro/química , Imagenología Tridimensional/métodos , Luz , Modelos Teóricos , Difracción de Neutrones/métodos , Estadística como Asunto , Difracción de Rayos X/métodos
2.
J Agric Food Chem ; 51(10): 3157-61, 2003 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-12720408

RESUMEN

Red radish anthocyanin extract, which consists of 12 known acylated anthocyanins, was reacted with 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) to generate peroxyl radicals under acidic pH conditions at 37 degrees C. The reaction products were isolated using preparative HPLC, and their chemical structures were determined to be p-hydroxybenzoic acid (1), 6-O-(E)-p-coumaroyl-2-O-beta-d- glucopyranosyl-alpha-d-glucopyranoside (3), p-coumaric acid (4), 6-O-(E)-feruloyl-2-O-beta-d-glucopyranosyl-alpha-d-glucopyranoside (5), and ferulic acid (6). Some products were not identified. HPLC analyses of the mixture of acylated pelargonidin isolated from red radish and AAPH revealed that the acylated pelargonidins possess the radical scavenging ability on some common sites even if the characteristics of the intramolecular acyl units are different. Degradation rates of acylated pelargonidins and the formation rates of the resulting reaction products were found to be quite different.


Asunto(s)
Antocianinas/análisis , Antocianinas/química , Peróxidos/química , Raphanus/química , Acilación , Cromatografía Líquida de Alta Presión , Ácidos Cumáricos/química , Ácidos Cumáricos/aislamiento & purificación , Hidroxibenzoatos/química , Hidroxibenzoatos/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Propionatos , Verduras/química
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