排序方式: 共有37条查询结果,搜索用时 15 毫秒
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A.B. BAUTISTA‐ORTÍN P. RODRÍGUEZ‐RODRÍGUEZ R. GIL‐MUÑOZ E. JIMÉNEZ‐PASCUAL N. BUSSE‐VALVERDE A. MARTÍNEZ‐CUTILLAS J.M. LÓPEZ‐ROCA E. GÓMEZ‐PLAZA 《Australian Journal of Grape and Wine Research》2012,18(2):123-130
Background and Aims: The evolution of seed tannins in three grape varieties grown in the same vineyard was followed from preveraison to harvest, to determine their pattern of accumulation. Also, to elucidate whether the use of 70% acetone as extracting solvent overestimate what will occur during fermentation, seed tannins were extracted throughout the ripening period with a method that involved a 3 days extraction with aqueous 12.5% ethanol and the results compared with the acetone extraction method. Methods and Results: For both methods, the extracted tannins were analysed following acid‐catalysis in the presence of excess of phloroglucinol. Seed tannins reached a maximum around veraison and decreased towards maturity, the mean degree of polymerization (mDP) varying only slightly during the studied period. When tannins were extracted with 12.5% ethanol, their concentration was much higher during the first part of the maturation than using acetone but was significantly lower at harvest. Conclusions: The decrease in extractable seed tannins during ripening was observed with both solvents. The differences observed in the concentration of tannins with both solvents could be due to the histochemical changes occurring in seeds during maturation. Significance of the Study: The differences observed in tannin concentration with the two different methods may indicate that when pulp maturity is reached before seeds are ripe, the fermenting solution will extract more tannins than the acetone method. These results point to the importance of extraction methodology when monitoring seed maturity for the prediction of seed tannins in wine. 相似文献
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C.A.?MARTíNEZ-HUITLE S.?FERRO A.?DE BATTISTIEmail author 《Journal of Applied Electrochemistry》2005,35(11):1087-1093
Mass transfer measurements were carried out to test a disk-shaped parallel-plate electrochemical cell, based on a new design.
The impinging-jet-cell concept, confined between parallel plates, was adapted to a configuration with one central inlet and
several peripheral exit sections, leading to more effective hydrodynamics within the cell. Measurements of mass transfer coefficient
were performed using the limiting diffusion current technique based on ferro-cyanide ion oxidation, and overall mass transfer
coefficients were correlated to Reynolds numbers ranging from 30 to 200.
A comparison with literature on similar devices showed higher mass transfer coefficients can be obtained in the cell described
in the present work. From the mass transfer standpoint, this type of cell could be a valuable tool in electrochemical wastewater
treatment applications.
The electrochemical oxidation of oxalic acid was tested at different anode materials (Pb/PbO2, boron-doped diamond, Ti/Pt and Ti/IrO2–Ta2O5), showing that the new cell design enables limitations usually encountered with conventional batch cells to be overcome.
However, the nature of the anode material remains an important parameter for the elimination of organic substrates. 相似文献
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MARÍA D GARCÍA‐PARRA ANA B CAMPELO BLANCA E GARCÍA‐ALMENDÁREZ CARLOS REGALADO ANA RODRÍGUEZ BEATRIZ MARTÍNEZ 《International Journal of Dairy Technology》2010,63(4):523-529
Lactococcus lactis UQ2 is a wild nisin A producer isolated from a Mexican cheese that grows poorly in milk. Conjugal matings with L. lactis NCDO712 to transfer the Lac+ Prt+ plasmid pLP712 and selection with nisin and lactose yielded L. lactis NCDO712 NisA+. Naturally rifampicin resistant L. lactis UQ2Rif was isolated to provide an additional selective marker. The identity of a transconjugant L. lactis UQ2Rif Lac+ was confirmed by RAPD‐PCR fingerprinting, nisA PCR amplification, nisin production, presence of pLP712 and phospho‐β‐galactosidase activity. This strain performed well in milk and synthesised 200 IU/mL nisin, 40 times more than the original strain. 相似文献
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E.A. MARTÍN-TOVAR L.G. DAZA A.J.R. LÓPEZ-ARREGUÍN A. IRIBARREN R. CASTRO-RODRIGUEZ 《中国有色金属学会会刊》2017,27(9):2055-2062
Al-doped ZnO (AZO) thin films were deposited on glass substrates by rf-sputtering at room temperature. The effects of substrate rotation speed (ωS) on the morphological, structural, optical and electrical properties were investigated. SEM transversal images show that the substrate rotation produces dense columnar structures which were found to be better defined under substrate rotation. AFM images show that the surface particles of the samples formed under substrate rotation are smaller and denser than those of a stationary one, leading to smaller grain sizes. XRD results show that all films have hexagonal wurtzite structure and preferred c-axis orientation with a tensile stress along the c-axis. The average optical transmittance was above 90% in UV-Vis region. The lowest resistivity value (8.5×10?3 Ω·cm) was achieved at ωS=0 r/min, with a carrier concentration of 1.8×1020 cm?3, and a Hall mobility of 4.19 cm2/(V·s). For all other samples, the substrate rotation induced changes in the carrier concentration and Hall mobility which resulted in the increasing of electrical resistivity. These results indicate that the morphology, structure, optical and electrical properties of the AZO thin films are strongly affected by the substrate rotation speed. 相似文献
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M. CALDERA R. A. MARTÍNEZ R. E. BOERI J. A. SIKORA 《Fatigue & Fracture of Engineering Materials & Structures》2011,34(10):774-781
Austempered ductile iron (ADI) suffers an embrittlement phenomenon when loaded in contact with water and other liquids. This phenomenon causes noticeable drops in elongation, ultimate tensile strength and fracture toughness of ADI of different strength grades. This paper studies the susceptibility to embrittlement of a new kind of austempered ductile iron called dual phase ADI (DPADI), which shows a matrix composed by the typical ausferrite present in ADI mixed with allotriomorphic ferrite. The new material is obtained by means of specific heat treatments that involve a partial austenitising stage. The susceptibility of DPADI to this type of embrittlement was evaluated by carrying out tensile tests in dry and wet conditions. Fracture surfaces were observed using scanning electron microscopy. The results showed a gradual decrease of the degree of embrittlement caused by contact with water as the ferrite content in the matrix increases. 相似文献