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Florica Papa Catalin Negrila Akane Miyazaki Ioan Balint 《Journal of nanoparticle research》2011,13(10):5057-5064
Well-dispersed, uniform monometallic Pt and bimetallic Pt–Cu, and Pt–Ag nanoparticles protected with PVP have been synthesized
by a modified-protocol alkaline polyol method. The nanoparticles were characterized by various methods (TEM, XPS, and XRD)
to elucidate the relationship between morphology and preparation variables. The average of monodispersed nanoparticles ranged
between 4.1 and 4.9 nm. Core–shell structure was obtained in the case of bimetallic nanoparticles. The core of bimetallic
nanoparticles was found to be rich in platinum, whereas the shell contained mostly copper or silver. The final structure of
bimetallic nanoparticles was found to be determined by the morphology particles resulted in the first reduction step. Explanations
are advanced on the light of experimental results. 相似文献
67.
Effects of thermo-hygro-mechanical densification on the surface characteristics of trembling aspen and hybrid poplar wood veneers 总被引:2,自引:0,他引:2
Papa Niokhor Diouf Tatjana StevanovicAlain Cloutier Chang-Hua FangPierre Blanchet Ahmed KoubaaNicolas Mariotti 《Applied Surface Science》2011,257(8):3558-3564
The effect of thermo-hygro-mechanical (THM) densification temperature on the surface color, roughness, wettability, and chemical composition of trembling aspen (Populus tremuloides) and hybrid poplar (Populus maximowiczii × P. balsamifera) veneers was investigated. Veneers were subjected to four THM densification temperatures (160 °C, 180 °C, 200 °C, and 220 °C). Veneer color darkened with increasing THM densification temperature. Surface roughness decreased between 160 °C and 200 °C. Wettability decreased after THM densification, but no significant difference was found between treated specimens. ATR-FTIR and XPS results confirmed that THM densification caused major chemical changes in veneer surfaces, and more pronounced at temperatures higher than 160 °C. 相似文献
68.
Pamela Quiroz Bernd Halbedel Angel Bustamante Juan C. Gonz��lez 《Hyperfine Interactions》2011,202(1-3):97-106
A series of M-type barium hexaferrite has been synthesized in a glass melt by partially substituting the Fe2O3 with TiO2 for investigation of their structure. The glass melt has the basic composition (mol%): 40 BaO + 33 B2O3 + (27-x) Fe2O3 + x TiO2 with x =?0, 3.6, 5.4 and 7.2 mol% TiO2. The substituted ferrites were studied by means of X-ray diffraction, Mössbauer spectroscopy and vibration sample magnetometer. X-ray diffraction studies revealed that not all samples have a single ferritic phase, a small second phase corresponding to BaTi6O13 was also observed to form. The Mössbauer spectra changed from magnetically ordered (x =?0) to magnetically ordered with strong line broadening. Moreover, the broadening increases with TiO2 content. The Mössbauer parameters suggested that Ti4?+? occupies the 2a and 12k crystal sites, and the Ti4?+? substitution on the 2b and 4f2 site also occurs at high melt dopings. Therefore, coercivity and saturation magnetization decreased. 相似文献
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A. Di Pietro G. Cardella A. Musumarra M. Papa G. Pappalardo F. Rizzo A. De Rosa A. D'Onofrio G. Inglima V. Roca M. Romano M. Romoli M. Sandoli F. Terrasi E. Fioretto 《Zeitschrift für Physik A Hadrons and Nuclei》1994,350(3):199-205
The28Si+64Ni reaction at 163.8 MeV incident energy is studied by measuring in coincidenceγ-rays and charged particles identified from Z=2 to Z=16. The transition from quasi-elastic to more damped reactions is observed when the difference between the detected charge and the projectile one is increased. The strong influence of the particle decay on the measuredγ-ray multiplicity is evidenced with the help of the statistical model computer code CASCADE. Dissipative events are well described in the rolling limit with excitation energy equally shared between the fragments. The overall agreement is lost for the fragments with the projectile charge which show a small value of theγ-multiplicity even for dissipative events. This is probably connected with the previously observed non statistical behavior of gamma rays emitted in coincidence with projectile-like fragments. In the alpha-spectrum measured in coincidence with gamma-rays, the deexcitation of fused systems is clearly separated from in flight emission of deep inelastic fragments. The low measured gamma-ray multiplicity for fusion events is qualitatively explained taking into account the effect of alpha-emission in the statistical decay. 相似文献