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排序方式: 共有90条查询结果,搜索用时 15 毫秒
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T. Kubo M. Belkacem V. Latora A. Bonasera 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(2):145-148
Intermittent behaviour of fragment multiplicity distributions in the nuclear liquid-gas phase transition is studied in terms of the droplet model of Fisher. The anomalous fractal dimensions are compared with data on heavy ion reactions and classical molecular dynamics simulations. A signature of the transition in the anomalous fractal dimensions is shown.We thank Profs. S. Ayik, M. Di Toro and V. Kondratyev for discussions. One of us (T.K.) acknowledges the support of INFN-LNS. 相似文献
3.
Mounir Maafi Belkacem Laassis Jean-Jacques Aaron M. Carmen Mahedero Arsenio Muñoz De La Peña Francisco Salinas 《Journal of inclusion phenomena and macrocyclic chemistry》1995,22(3):235-247
The photooxidation of Azure A and fluorescence properties of Azure A and its photoproduct have been investigated in aqueous media and in the presence of-cyclodextrin (-CD). The fluorescence intensity of the complex formed between the photoproduct and -CD was found to be three times higher than that of the uncomplexed Azure A photoproduct. A complex formation constant of 110±40 M–1 was calculated using the Benesi-Hildebrand treatment of the fluorescence emission data. Although the stoichiometry of the Azure A photoproduct: -CD complex was found to be 1: 1, it seems that the Azure A structure is only partially included. Calibration graphs were plotted for the free Azure A photoproduct and the photogenerated product included in -CD. The analytical parameters and quantification limits were determined. 相似文献
4.
A novel electrochemical sensor for ascorbic acid (AA) detection based on platinum electrode modified with polyterthiophene (P3T) and doped with metallic particles (Cu, Co, Ag, Au, Pd) was constructed. The electrocatalytic performances of the modified electrode with polyterthiophene-metallic particles related to the detection of AA, showed a better catalytic activity compared to the modified electrode with polyterthiophene film. The obtained results demonstrate also that the use of P3T–Ag nanocomposite allows a good sensitivity; which gives a high response in oxidation peak of AA. In order to have a good performance using this sensor, several parameters such as polymerization time of the film and immersion time of the film in AgNO3 solution were optimized. 相似文献
5.
Mostefa Sayhi Nasreddine Haine Belkacem Belaabed Valérie Vigneras 《Journal of Macromolecular Science: Physics》2015,54(10):1183-1195
Conducting polymer blends were prepared using polyaniline doped with para- toluene sulfonic acid (PTSA-PANI) and a polyester polyol-based polyurethane (PU). The morphological, thermal and dielectric properties of the PTSA-PANI/PU blends in the frequency range of 1–5 GHz (S band) were investigated. It was found that the morphology of the samples was affected by the PTSA-PANI loading, resulting in the formation of agglomerates and pathways when above 10 wt%. The thermal stability of the composites was improved with increased PTSA-PANI loading. The electrical conductivity percolation threshold was obtained at 2.5% of PTSA-PANI loading and the electrical conductivity reached the value of 0.13 S/m at a PTSA-PANI loading of 30 wt%. The obtained results for the PTSA-PANI/PU blends prepared indicate a high potential for their successful use in electrical and electromagnetic applications. 相似文献
6.
Leila Hasniou Belkacem Nessark Naima Maouche 《Russian Journal of Applied Chemistry》2017,90(4):633-640
In the present work, a new composite material poly(3T + 6T + TiO2) was electrochemically synthesized. This composite material was synthesized in a solution of (CH2Cl2/TBAP) containing the monomers (terthiophene), (sexithiophene) and semiconductor (TiO2) particles. The preparedsamples were characterized electrochemically by cyclic voltamperometry (CV) and spectrometry analysis by scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) absorption spectroscopy, energy dispersive X-ray spectroscopy (EDX) and fourier transform infrared spectroscopy (FTIR), respectively. The effect of TiO2 concentration in the solution on dispersed microparticle entity and on the photocurrent response was investigated. The results showed that TiO2 particles were dispersed and codeposited into the copolymer poly(3T + 6T + TiO2) matrix, and titanium atom was confirmed by EDX spectra. From SEM images, the TiO2 has a spherical shape and micrometer size. The FTIR spectrum indicated that titanium dioxide do not show a significant modification in terms of band shape and no interaction between polymers and TiO2 particles. Furthermore, the results showed that the composite films with different amounts of TiO2 exhibit good photocurrent properties which imply that these composites films can be used in various fields, such as photoelectrochemical applications as photovoltaic cells. 相似文献
7.
Armspach D Poorters L Matt D Benmerad B Balegroune F Toupet L 《Organic & biomolecular chemistry》2005,3(14):2588-2592
1,3-Bis[bis(4-tert-butylphenyl)chloromethyl]benzene and 1,3-bis[bis(4-anisyl)chloromethyl]benzene were employed as regioselective capping reagents for the preparation of C-6A,C-6B-bridged, permethylated alpha- and beta-CD derivatives; isolated yields up to 55% of proximally capped, methylated CDs were obtained, thus opening the way to the straightforward preparation of a wide range of A,B-functionalised CDs. As revealed by a single crystal X-ray diffraction study, the benzene-1,3-bis[bis(4-tert-butylphenyl)methyl] spacer is perfectly suited for A,B-capping of beta-cyclodextrin. 相似文献
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9.
Belkacem Manser Idir Belaidi Abderrachid Hamrani Sofiane Khelladi Farid Bakir 《Comptes Rendus Mecanique》2019,347(2):141-165
A wisely chosen geometry of micro textures with the favorable relative motion of lubricated surfaces in contacts can enhance tribological characteristics. In this paper, a computational investigation related to the combined influence of bearing surface texturing and journal misalignment on the performances of hydrodynamic journal bearings is reported. To this end, a numerical analysis is performed to test three texture shapes: square “SQ”, cylindrical “CY”, and triangular “TR”, and shaft misalignment variation in angle and degree. The Reynolds equation of a thin viscous film is solved using a finite differences scheme and a mass conservation algorithm (JFO boundary conditions), taking into account the presence of textures on both full film and cavitation regions. Preliminary results are compared with benchmark data and are consistent with a positive enhancement in misaligned bearing performances (load carrying capacity and friction). The results suggest that the micro-step bearing mechanism is a key parameter, where the micro-pressure recovery action present in dimples located at the second angular part of the bearing (from 180° to 360°) can compensate for the loss on performances caused by shaft misalignment, while the micro-pressure drop effect at the full film region causes poor performances. Considering the right arrangement of textures on the contact surface, their contours geometries can have a significant impact on the performance of misaligned journal bearings, particularly at high eccentricity ratios, high misalignment degrees and when the misalignment angle α approaches to or . 相似文献
10.
Multivariate kernel density estimators are known to systematically deviate from the true value near critical points of the density surface. To overcome this difficulty a method based on Rao–Blackwell's theorem is proposed. Local corrections of kernel density estimators are achieved by conditioning these estimators with respect to locally sufficient statistics. The asymptotic as well as the small sample size behavior of the improved estimators are studied. Asymptotic bias and variance are investigated and weak and complete consistency are derived under mild hypothesis. 相似文献