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Enzo Benedetti Aldo D'Alessio Mauro Aglietto Giacomo Ruggeri Piergiorgio Vergamini Francesco Ciardelli 《Polymer Engineering and Science》1986,26(1):9-14
Polyolefins functionalized with diethylmaleate were mixed with poly(vinylchloride) (PVC) in different compositions. Intermolecular interactions involving the carbonyl groups of the side chains of the functionalized polyolefins and methine hydrogens of PVC were investigated by means of infrared spectroscopy. The major flexibility of the ester groups attached to the backbone chains, with respect to polyesters, seems to increase the capability of such groups to interact with groups of more polar polymers, thus allowing prediction of easier miscibility, which however also depends on the starting polyolefin structure and function-alization degree. 相似文献
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An overview about the development of porous bioresorbable composite materials for applications as scaffolds in tissue engineering is presented. A thermally induced phase separation method was developed to fabricate porous foam-like structures of poly(lactide-co-glycolide) (PLGA) containing bioactive glass particle additions (up to 50 wt.%) and exhibiting well-defined, oriented and interconnected porosity. The in vitro bioactivity and the degradability of the composite foams were investigated in contact with phosphate buffer saline (PBS). Weight loss, water absorption and molecular weight measurements were used to monitor the polymer degradation after incubation periods of up to 7 weeks in PBS. It was found that the presence of bioactive glass retards the polymer degradation rate for the time period investigated. The present results show a way of controlling the in vitro degradation behaviour of PLGA porous composite scaffolds by tailoring the concentration of bioactive glass. 相似文献
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Franco Chialva Carlotta Frattini Aldo Martelli 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1985,181(1):32-34
Summary The essential oil obtained by steam distillation of cinchona bark (Cinchona spp.,Rubiaceae family) — a plant well known for its pharmacological properties, also employed in the food industry, especially in making liqueurs - was investigated. The oil, of completely unknown chemical composition, was analyzed by GLC and GLC/MS after separation on a silica gel column, and one hundred components were identified. The presence of 2-hexyl-3-methylmaleic anhydride is rather unusual.
Ungewöhnliche ätherische Öle mit aromatischen Eigenschaften. Die flüchtigen Aromastoffe der China-Rinde
Zusammenfassung Es wurde ätherisches Öl analysiert, das durch Wasserdampfdestillation von Chinarinde (Cinchona spp. derRubiaceae-Familie) gewonnen wurde. Diese Pflanze ist aufgrund ihrer pharmakologischen Eigenschaften bekannt und wird auch in der Lebensmittelindustrie verwendet, ganz besonders für die Likör- und Magenbitterherstellung. Die chemische Zusammensetzung dieses Öls war unbekannt. Nach Abtrennung auf einer Kieselgelsäule wurden im Öl mit GLC und GLC/MS etwa 100 Verbindungen identifiziert. Das Vorhandensein von 2-Hexyl-3-methyl-maleinsäureanhydrid ist ziemlich ungewöhnlich.相似文献
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Prati C. Rocca F. Kost Y. Damonti E. 《Geoscience and Remote Sensing, IEEE Transactions on》1991,29(6):934-941
For high-quality SAR (synthetic aperture radar) processing, the Doppler centroid frequency is needed. However, SAR data are sampled along the azimuth direction at the pulse repetition frequency (PRF); the estimation of the Doppler centroid frequency by means of spectral analysis techniques may produce ambiguous results due to aliases. The mathematical expression of the residual error that occurs when SAR data are focused with an incorrect alias of the PRF is thus derived. Then, a blind deconvolution technique is used to estimate the actual PRF replica from the focused image. Squinted X -band data, corresponding to those that will be generated by the SIR-C mission, have been generated from the JPL-AirSAR L - and C -band data by means of an inversion of the focusing process. Even if the real data may show differences with respect to the simulated data, the blind deconvolution method appears to be more precise and robust than the other conventional techniques tested 相似文献
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Watson M.E. Chilla J.L.A. Rocca J.J. Kim J.-W. Lile D.L. Vogt T.J. Robinson G.Y. 《Quantum Electronics, IEEE Journal of》1995,31(2):254-260
We report modulation saturation and time response measurements on InGaAs-InGaP MQW modulators. The measurements yield a saturation intensity of (3.7±0.1) kW/cm2 for a 0-10 V swing and switching times between 10 and 90 ns, depending on the bias voltage and incident light intensity. The observed dependence indicates that field screening due to carrier build-up is the dominant physical mechanism determining both the speed and the saturation intensity. This conclusion is supported by results of theoretical calculations 相似文献
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