排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Samia Mahouche Nejib Mekni Leila Abbassi Philippe Lang Christian Perruchot Mohamed Jouini Fayna Mammeri Mireille Turmine Hatem Ben Romdhane Mohamed M. Chehimi 《Surface science》2009,603(21):3205-3211
Bis-alkynylated oligoethyleneglycol (OEG) and a monopropargyl-functionalized perfluorinated ethylene glycol (FEG) were clicked to azide-functionalized gold surface (Au–N3) at room temperature via the well known 1,3 cycloaddition click chemical reaction. The Au–N3 substrate was obtained by nucleophilic attack of NaN3 on gold substrates modified by the electrochemical reduction of the , +N2–C6H4–CH2Br diazonium salt. This electrochemical process yields aryl layer-modified gold of the type Au–C6H4–CH2Br (hereafter Au–Br). The untreated and modified gold plates were examined by XPS, PMIRRAS and contact angle measurements. XPS brought evidence for electrografting aryl layers by the detection of Br3d; azide functionalization by the increase of the N/Br atomic ratio; and click reaction of OEG with Au–N3 by the increase of O/N ratio. In addition, the perfluorinated plate (Au-FEG) exhibited F1s and characteristic C1s peaks from -(CF2)7- chain and terminal CF3. Infra red spectroscopy (PMIRRAS) evidenced (i) grafting N3 to Au–Br; (ii) characteristic stretching bands, from ethylene glycol units, C–O–C (1100–1300 cm−1); CF2 (1000–1100 cm−1) and CF3 (1100–1350 cm−1) from FEG grafts; and (iii) suppression of alkynyl bands from OEG and FEG after surface click chemistry. More importantly, PMIRRAS results support an important bridging of the bispropargyl oligoethylene glycol at the gold surface. Water drop contact angles were found to be 48.7° and 83.0° for Au-OEG and Au-FEG, respectively, therefore highlighting the control over the hydrophilic/hydrophobic character of the clicked substrate.This work shows that clicking macromolecules to grafted, diazonium salt-derived aryl layers is a novel, simple and valuable approach for designing robust, functional surface organic coatings. 相似文献
2.
Y. Mammeri 《Acta Appl Math》2012,117(1):1-13
We study the periodic solution of a perturbed regularized Boussinesq system (Bona et al., J. Nonlinear Sci. 12:283–318, 2002, Bona et al., Nonlinearity 17:925–952, 2004), namely the system η
t
+u
x
+β(−η
xxt
+u
xxx
)+α((ηu)
x
+ηη
x
+uu
x
)=0,u
t
+η
x
+β(η
xxx
−u
xxt
)+α((ηu)
x
+ηη
x
+uu
x
)=0, with 0<α,β≤1. We prove that the solution, starting from an initial datum of size ε, remains smaller than ε for a time scale of order (ε
−1
α
−1
β)2, whereas the natural time is of order ε
−1
α
−1
β. 相似文献
3.
NMR Spectroscopic Assignment of Backbone and Side‐Chain Protons in Fully Protonated Proteins: Microcrystals,Sedimented Assemblies,and Amyloid Fibrils 下载免费PDF全文
Dr. Jan Stanek Dr. Loren B. Andreas Dr. Kristaps Jaudzems Dr. Diane Cala Dr. Daniela Lalli Andrea Bertarello Dr. Tobias Schubeis Dr. Inara Akopjana Dr. Svetlana Kotelovica Prof. Kaspars Tars Dr. Andrea Pica Dr. Serena Leone Prof. Delia Picone Dr. Zhi‐Qiang Xu Prof. Nicholas E. Dixon Dr. Denis Martinez Mélanie Berbon Nadia El Mammeri Dr. Abdelmajid Noubhani Dr. Sven Saupe Dr. Birgit Habenstein Dr. Antoine Loquet Dr. Guido Pintacuda 《Angewandte Chemie (International ed. in English)》2016,55(50):15504-15509
We demonstrate sensitive detection of alpha protons of fully protonated proteins by solid‐state NMR spectroscopy with 100–111 kHz magic‐angle spinning (MAS). The excellent resolution in the Cα‐Hα plane is demonstrated for 5 proteins, including microcrystals, a sedimented complex, a capsid and amyloid fibrils. A set of 3D spectra based on a Cα–Hα detection block was developed and applied for the sequence‐specific backbone and aliphatic side‐chain resonance assignment using only 500 μg of sample. These developments accelerate structural studies of biomolecular assemblies available in submilligram quantities without the need of protein deuteration. 相似文献
4.
S. Mammeri H. Ammi A. Dib C.A. Pineda-Vargas S. Ourabah M. Msimanga M. Chekirine A. Guesmia 《Radiation Physics and Chemistry》2012,81(12):1862-1866
Stopping power and energy loss straggling data for protons (1H+) and alpha particles (4He+) crossing Formvar thin polymeric foils (thickness of ~0.3 μm) have been measured in the energy range (0.3–2.7) MeV by using the indirect transmission technique. The determined stopping power data were compared to SRIM-2010, PSTAR or ASTAR calculation codes and then analyzed in term of the modified Bethe–Bloch theory to extract the target mean excitation and ionization potential 〈I〉. A resulting value of 〈I〉≈(69.2±1.8) eV was deduced from proton stopping data. The measured straggling data were corrected from surface roughness effects due to target thickness inhomogeneity observed by the atomic force microscopy (AFM) technique. The obtained data were then compared to derived straggling values by Bohr's and Bethe–Livingston's classical theories or by Yang's empirical formula. A deviation of ~40%–80% from the Bohr's straggling value has been observed for all reported energies, suggesting that the Bohr theory cannot be correctly applied to describe the electronic energy loss straggling process with the used low thickness of Formvar foil. The inner-shell contribution of target electrons to energy loss process is also advanced to explain the observed deviation from experiment in case of He+ ions. Finally, the reliability of Bragg's additivity rule was discussed in case of stopping power and straggling results. 相似文献
5.
Mammeri O. A. Hamoud F. Sobina A. A. Ramsh S. M. Fundamensky V. S. Gurzhiy V. V. Khrabrova E. S. 《Russian Journal of General Chemistry》2020,90(11):2043-2047
Russian Journal of General Chemistry - Condensation of 1,3-dialkylthiourea, formaldehyde, and terminal amino acids (C2, C3, or C4) taken in the 1 : 2 : 1 molar ratio has afforded the terminally... 相似文献
6.
Youcef Mammeri 《Applicable analysis》2013,92(12):2526-2535
We study the unique continuation property for the generalized Kadomtsev–Petviashvili (KP) equations and its regularized version. We use Carleman estimates to prove that if the solution of the KP equations vanishes in an open subset, then this solution is identically equal to zero in the horizontal component of the open subset. 相似文献
7.
In the present contribution, we report results on energy straggling of He ions penetrating Mylar and polypropylene thin polymeric foils. The measurements were performed in the 900–3000 keV incident particle energy range by using the indirect transmission technique developed previously. The experimental straggling data are corrected to consider the roughness effects due to target thickness inhomogeneity. As expected, the roughness contribution to straggling is more important for helium than for proton ions and decreases as the ion energy increases. At low velocities, (<500 keV/amu), the variation of the experimental energy straggling results differs strongly from predictions based on Bohr’s formalism, and with increasing energies, the experimental results approach gradually the Bohr values. 相似文献
8.
9.
Jan Stanek Loren B. Andreas Kristaps Jaudzems Diane Cala Daniela Lalli Andrea Bertarello Tobias Schubeis Inara Akopjana Svetlana Kotelovica Kaspars Tars Andrea Pica Serena Leone Delia Picone Zhi‐Qiang Xu Nicholas E. Dixon Denis Martinez Mlanie Berbon Nadia El Mammeri Abdelmajid Noubhani Sven Saupe Birgit Habenstein Antoine Loquet Guido Pintacuda 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(50):15730-15735
10.
Fayna Mammeri Laurence Rozes Clement Sanchez Eric Le Bourhis 《Journal of Sol-Gel Science and Technology》2003,26(1-3):413-417
Nano-indentations using a Berkovich indenter were performed in order to analyze the mechanical properties of hybrid organic-inorganic coatings. This technique allows to measure low load deformations and therefore to estimate quantitatively mechanical properties of the coatings. The elastic modulus and the hardness were determined on the basis of the load-displacement curve. We report results obtained for class II hybrid coatings based on SiO2-PMMA prepared by sol-gel process. The effects of coating composition were investigated. 相似文献