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101.
M. Gaillardin S. Girard Y. Ouerdane A. Boukenter F. Andrieu C. Tabone O. Faynot 《Journal of Non》2011,357(8-9):1989-1993
This study describes investigations on the ionizing radiation effects induced in ultra-thin Silicon-On-Insulator (SOI) devices. Electrical tests exhibit various behaviors after irradiation which depends on the intrinsic mechanical stress of the thin silicon film. The electrical characteristics of strained Silicon-On-Insulator devices evidence a decrease of the subthreshold slope that may be related to a radiation induced degradation of the carrier mobility. This appears in addition to the deviation of the threshold voltage classically observed on irradiated Silicon-On-Insulator samples. The major issue discussed in this paper is whether a strain relaxation or the buildup of interface states at strained silicon/silica interfaces leads to the observed carrier mobility degradation. Radiation-induced mechanisms are then discussed with electrical measurements and optical spectra obtained by confocal microscopy measurements which have already demonstrated their potential to probe irradiated materials. 相似文献
102.
Laroche M Chardon AM Nilsson J Shepherd DP Clarkson WA Girard S Moncorgé R 《Optics letters》2002,27(22):1980-1982
Efficient repetitive passive Q switching of a cladding-pumped Er-Yb fiber laser has been demonstrated by use of an external-cavity configuration containing a Co(2+): ZnS crystal as a saturable absorber. Energies of as much as 60muJ in pulses of durations as short as 3.5 ns (FWHM), corresponding to a peak power of >10kW, have been generated, and the maximum slope efficiency with respect to the absorbed pump power was 13%. Using a bulk diffraction grating in the Littrow configuration to provide wavelength-selective feedback, we tuned the passively Q -switched fiber laser over 31 nm from 1532 to 1563 nm. The prospects for further improvement in performance are discussed. 相似文献
103.
104.
We present a fast tabu search method for the design of access tree networks. We connect a population of users to a set of switches using a variety of SONET channels on fiber optics links and ADM equipment at the nodes. We specifically take into account the economies of scale provided by the transmission systems and the transmission hierarchy of SONET systems.We describe in detail the parameters used for defining neighborhoods, penalty parameters, data structure and indicate how this can lead to substantial improvements of the overall computational time while providing costs lower than those of a more straightforward method. Results are provided for a set of random cases as well as for a real network. 相似文献
105.
Jérôme Girard Priscilla S. Brunetto Olivier Braissant Zarko Rajacic Nina Khanna Regine Landmann Alma U. Daniels Katharina M. Fromm 《Comptes Rendus Chimie》2013,16(6):550-556
A silver polystyrene sulfonate polyelectrolyte was synthesized, showing a spontaneous reduction of silver ions to silver nanoparticles over a period of approximately 1 month. A follow-up of the nanoparticle formation via scanning electron microscopy (SEM) reveals migration of the nanoparticles towards the cracks of the polymer over time, leading to a self-healing process of the nanocomposite. Antibacterial tests show excellent antibacterial activity of our compound, which allows us to use this compound e.g. for external medical applications. 相似文献
106.
Girard F Antoni M Faure S Steinchen A 《Langmuir : the ACS journal of surfaces and colloids》2006,22(26):11085-11091
Evaporation dynamics of small sessile water droplets under microgravity conditions is investigated numerically. The water-air interface is free, and the surrounding air is assumed to be quasisteady. The droplet is described by Navier-Stokes and heat equations and its surrounding water/air gaseous phase with Laplace equation. In the thermodynamic conditions of the simulations presented herein, the evaporative mass flow is nonlinear. It shows a minimum that indicates the existence of qualitative changes in the evaporative regimes although the droplet is sessile. Due to temperature gradients on the free interface, Marangoni motion occurs and generates inside the droplet convection cells that furthermore exhibit small fluctuating motion as evaporation goes on. 相似文献
107.
Site of protonation of nicotine and nornicotine in the gas phase: pyridine or pyrrolidine nitrogen? 总被引:1,自引:0,他引:1
Graton J Berthelot M Gal JF Girard S Laurence C Lebreton J Le Questel JY Maria PC Naus P 《Journal of the American Chemical Society》2002,124(35):10552-10562
The gas-phase basicities (GBs) of nornicotine, nicotine, and model pyrrolidines have been measured by FT-ICR. These experimental GBs are compared with those calculated (for the two sites of protonation in the case of nicotine and nornicotine) at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d,p) level, or those estimated from substituent effects on the GBs of 2-substituted pyrrolidines, 2-substituted N-methylpyrrolidines, and 3-substituted pyridines. It is found that, in contrast to the Nsp(3) protonation in water, in the gas phase nornicotine is protonated on the pyridine nitrogen, because the effects of an intramolecular CH.Nsp(3) hydrogen bond and of the polarizability of the 3-(pyrrolidin-2-yl) substituent add up on the Nsp(2) basicity, while the polarizability effect of the 2-(3-pyridyl) substituent on the Nsp(3) basicity is canceled by its field/inductive electron-withdrawing effect. The same structural effects operate on the Nsp(3) and Nsp(2) basicities of nicotine, but here, the polarizability effect of the methyl group puts the pyrrolidine nitrogen basicity very close to that of pyridine. Consequently, protonated nicotine is a mixture of the Nsp(3) and Nsp(2) protonated forms. 相似文献
108.
Barbara R. Hillery James E. Girard Michele M. Schantz Stephen A. Wise 《Journal of separation science》1995,18(2):89-96
A novel p,p-cyanobiphenyl stationary phase (p-cyanobiphenyl, p-allyloxy methylpolysiloxane) has been evaluated for the GC investigation of polychlorinated biphenyls (PCBs). Several PCB congeners which coelute on the phases typically used for PCB analysis (e.g. 5% phenyl methylpolysiloxane) are separated on the p,p-cyanobiphenyl phase, including the hexachlorobiphenyl congeners PCB 163, PCB 164, and PCB 138. In this work, a p,p-cyanobiphenyl stationary phase was used to measure selected PCB congeners in two Standard Reference Materials (SRMs) available from the National Institute of Standards and Technology (NIST), and two Certified Reference Materials (CRMs) available from the Community Bureau of Reference (BCR). The materials analyzed were SRM 1588, Organics in Cod Liver Oil; SRM 1945, Organics in Whale Blubber; CRM 349, Chlorobiphenyls in Cod Liver Oil; and CRM 350, Chlorobiphenyls in Mackerel Oil. Concentrations are reported for several PCB congeners which coelute on the 5% phenyl methylpolysiloxane, including PCB 163 and PCB 164. 相似文献
109.
García Ruano JL Gamboa AE Gutiérrez LG Martín Castro AM Rodríguez Ramos JH Yuste F 《Organic letters》2000,2(6):733-736
A new kind of chiral dienophiles, cyclic vinyl-p-tolylsulfilimines (2a and 2b), were obtained from the corresponding (Z)-sulfinylacrylonitriles with HBF(4) and methanol. The asymmetric Diels-Alder reaction of optically pure 2a with cyclopentadiene under mild thermal or catalyzed conditions afforded only the endo-4a adduct with complete endo and pi-facial selectivities. The ability of the sulfilimine moiety to enhance the dienophilic reactivity of the double bond is similar to that of the sulfinyl group. 相似文献
110.
The polymerization of styrene-in-water and methylmeth-acrylate-in-water microemulsions stabilized by nonionic surfactants
was investigated using different initiation techniques. Thermally induced initiation was carried out using potassium persulfate
(water soluble) and azobisiso-butyronitrile (AIBN) (oil soluble) at 60° and 50°C, respectively. When the monomer concentration
was kept below a certain limit, the particle size of the nanolatex was similar to the droplet size of the microemulsion precursor.
At higher monomer concentrations, the latex produced was significantly larger than the microemulsion droplets, as a result
of the possible coalescence of the microemulsion droplets during polymerization. By using chemically induced polymerization
(hydrogen peroxide+ascorbic acid) at temperatures below the cloud point temperature of the microemulsion or by photochemically
induced initiation at room temperature, it was possible to obtain nanolatex particles with similar size to the droplets up
to 10% monomer content. In all cases, the particle size was determined using photon correlation spectroscopy (PCS). Electron
micrographs of the microlatex particles were taken and these confirmed the measurements obtained by PCS. The molecular weight
of the polymers produced was determined by gel permeation chromatography. The average number of polymer molecules per particle
was calculated. It was shown in some cases that the nanolatex contained one polymer chain per particle. A mechanism was suggested
for polymerization and particle growth.
Received: 29 May 1997 Accepted: 28 May 1998 相似文献