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排序方式: 共有58条查询结果,搜索用时 15 毫秒
1.
Domenico Armenise Nicolino De Laurentis Antonia Reho Antonio Rosato Flaviano Morlacchi 《Journal of heterocyclic chemistry》2004,41(5):771-775
A series of 6‐fluoro‐4‐(5 or 7)‐chloro‐2‐(difluorobenzoyl)aminobenzothiazoles 3a‐r were prepared to investigate their potential biological activity. In this work, the results of their in vitro antifungal activity against some strains of Candida albicans are reported. It was found that some derivatives displayed antifungal activity higher than that for 3k [1a] compound already described in literature. 相似文献
2.
D. E. Daney M. P. Maley H. J. Boenig J. O. Willis J. Y. Coulter L. Gherardi G. Coletta 《Physica C: Superconductivity and its Applications》1998,310(1-4):236-239
We report single-phase AC loss measurements on 8-, 4-, and 3-layer, multi-strand, HTS prototype conductors for power transmission lines. We use both calorimetric and electrical techniques. The agreement between the two techniques suggests that the interlayer current distribution in 1-m long conductors are representative of those in long conductors. The losses for the 8- and 4-layer conductors are in rough agreement, with the 8-layer losses being somewhat lower. The 3-layer conductor losses are substantially higher — probably due to unbalanced azimuthal currents for this configuration. 相似文献
3.
Alois Kuhn María Martín Flaviano García-Alvarado 《Journal of solid state chemistry》2010,183(1):20-3508
The new ramsdellite series LiTi2−yVyO4 (0≤y≤1) has been prepared by conventional solid state chemistry techniques and was characterized by X-ray powder diffraction and electron diffraction. To our knowledge, this is the first report on ramsdellites containing vanadium. The magnetic behaviour of these ramsdellites is strongly influenced by its vanadium content. In this sense, LiTi2O4 (y=0) exhibits metallic-like temperature independent paramagnetism, but d electrons tend to localize with increasing V content. LiTiVO4, though also paramagnetic, follows then the Curie-Weiss law. The crossover from delocalized to localized electrons is observed between compositions y=0.6 and 0.8. For y≥0.8 the magnetic results evidence an isovalent substitution mechanism of trivalent Ti by V. The electrochemical lithium intercalation and deintercalation chemistry of LiTi2−yVyO4 is grouped into two different operating voltage regions. Reversible lithium deintercalation of vanadium-substituted ramsdellite titanates LiTi2−yVyO4 in the high voltage range 2-3 V vs. Li occurs in two main steps, one at about 2 V and the other at about 3 V. The 3 V process capacity increases with the vanadium content, while the 2 V capacity decreases at the same time. The vanadium to titanium substitution rate in LiTi2O4 was found to be beneficial to the specific energy in as much as a 50% increase (1 V) of the working voltage is observed. On the other hand, reversible lithium intercalation in vanadium-substituted ramsdellite titanates LiTi2−yVyO4 in the low voltage range 1-2 V vs. Li occurs in one main single step, in which the capacity is not affected by the vanadium content, although vanadium-doping produces an improved capacity retention with an excellent cycling behaviour observed for y≤0.6. 相似文献
4.
Soares SF Galvão RK Araújo MC da Silva EC Pereira CF de Andrade SI Leite FC 《Analytica chimica acta》2011,(1):30-28
This work proposes a modification to the successive projections algorithm (SPA) aimed at selecting spectral variables for multiple linear regression (MLR) in the presence of unknown interferents not included in the calibration data set. The modified algorithm favours the selection of variables in which the effect of the interferent is less pronounced. The proposed procedure can be regarded as an adaptive modelling technique, because the spectral features of the samples to be analyzed are considered in the variable selection process. The advantages of this new approach are demonstrated in two analytical problems, namely (1) ultraviolet–visible spectrometric determination of tartrazine, allure red and sunset yellow in aqueous solutions under the interference of erythrosine, and (2) near-infrared spectrometric determination of ethanol in gasoline under the interference of toluene. In these case studies, the performance of conventional MLR-SPA models is substantially degraded by the presence of the interferent. This problem is circumvented by applying the proposed Adaptive MLR-SPA approach, which results in prediction errors smaller than those obtained by three other multivariate calibration techniques, namely stepwise regression, full-spectrum partial-least-squares (PLS) and PLS with variables selected by a genetic algorithm. An inspection of the variable selection results reveals that the Adaptive approach successfully avoids spectral regions in which the interference is more intense. 相似文献
5.
Effects of aromatic regularity on the structure and conductivity of polyimide‐poly(ethylene glycol) materials doped with ionic liquid
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Elyse Coletta Michael F. Toney Curtis W. Frank 《Journal of Polymer Science.Polymer Physics》2015,53(7):509-521
An understanding of the structure and properties of polymer electrolyte systems can be crucial to a variety of different applications. The current work performs a study of the composition, structure and properties of poly(ethylene glycol) (PEG)‐aromatic polyimide systems incorporating ionic liquids that are relevant to several applications especially fuel cell membranes. Composition was varied through using different aromatic dianhydrides, aromatic diamines and in some cases synthesis solvent. Properties were characterized using Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, small‐angle x‐ray scattering, electrochemical impedance spectroscopy and cyclic voltammetry. By varying solvent, aromatic regularity and expected rigidity can be tuned, impacting average conductivity by 30%. Varying the aromatic diamine can influence the length scale and amount of aromatic regularity, which can ultimately affect the conductivity by a factor of four. The maximum conductivity reached was 83 mS/cm at 80 °C and 70 %RH. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 509–521 相似文献
6.
Lauceri R Fasciglione GF D'Urso A Marini S Purrello R Coletta M 《Journal of the American Chemical Society》2008,130(32):10476-10477
Kinetics of the porphyrin aggregation leading to a chiral memory system shows a remarkable "catalytic" effect of the noncovalent templates explaining their self-replication ability. 相似文献
7.
This paper reports the optimisation of a competitive immunoassay (ELISA) to detect lactosylated proteins in milk samples. The assay employs monoclonal antibodies for lactosylated proteins produced in our laboratory and requires no pre-treatment of the samples other than a dilution step. Monoclonal antibodies were fully characterised in terms of selectivity and cross-reactivity with structurally related molecules and used in a competitive assay format with lactosylated standard proteins (lactosylated ovalbumin). The detection limit for lactosylated ovalbumin was 0.015 microgram ml-1 and the working range was from 0.010 to 40 micrograms ml-1. The data obtained indicate that the ELISA developed is applicable to diluted milk samples and is able to distinguish between milk samples that have undergone different heat treatments (UHT and pasteurised milk). 相似文献
8.
Journal of Dynamics and Differential Equations - Existence of solutions connecting a singularity of a perturbed implicit differential equations is studied. It is assumed that the unperturbed... 相似文献
9.
Reduction of CrNbO4 under 5% H2/Ar at different temperatures has been carried out to obtain oxygen-deficient rutiles aiming for mixed ionic and electronic conductivities. Decomposition is observed at temperatures above 950 °C. Hence, the more reduced rutile that could be obtained corresponds to that obtained at 950 °C which has the composition CrNbO3.96. When compared with CrNbO4, the reduced product exhibits an electrical conductivity between three and four orders of magnitude higher. Both bulk and grain boundary conductivities are enhanced upon reduction. The small amount of vacancies generated by reduction does not induce oxygen conductivity. However, the presence of the corresponding small amount of Nb(IV) in the rutile affects strongly the electrical properties. This is likely related to the structural characteristics of rutile that allow for strong Nb–Nb interactions. On the other hand, no evidence of protonic conductivity has been found. 相似文献
10.
Many 13C-NMR studies dedicated to the π-(Arene)-tri-carbonylchromium(o) complexes are concerned with the origin of the large upfield shifts of the aromatic carbons on the coordination to the chromiumtricarbonyl group. This effect is not yet completely understood and various hypotheses have been formulated to justify it (1)(2)(3) (4). 相似文献