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排序方式: 共有458条查询结果,搜索用时 15 毫秒
91.
Jamila Obeid Jean-Pierre Magnin Jean-Marie Flaus Olivier Adrot John C. Willison Roumen Zlatev 《International Journal of Hydrogen Energy》2009
The photosynthetic bacterium, Rhodobacter capsulatus, produces hydrogen under nitrogen-limited, anaerobic, photosynthetic culture conditions, using various carbon substrates. In the present study, the relationship between light intensity and hydrogen production has been modelled in order to predict both the rate of hydrogen production and the amount of hydrogen produced at a given time during batch cultures of R. capsulatus. The experimental data were obtained by investigating the effect of different light intensities (6000–50,000 lux) on hydrogen-producing cultures of R. capsulatus grown in a batch photobioreactor, using lactate as carbon and hydrogen source. The rate of hydrogen production increased with increasing light intensity in a manner that was described by a static Baly model, modified to include the square of the light intensity. In agreement with previous studies, the kinetics of substrate utilization and growth of R. capsulatus was represented by the classical Monod or Michaelis–Menten model. When combined with a dynamic Leudekong–Piret model, the amount of hydrogen produced as a function of time was effectively predicted. These results will be useful for the automatization and control of bioprocesses for the photoproduction of hydrogen. 相似文献
92.
The desorption kinetic of trace elements (Cd, Zn, Co, Mn, Fe, Ag, and Cs) associated with Loire river natural suspended particulate matter (SPM; 0.4-63 microm) was followed up on times varying from 0.5 h to 30 days, from SPM previously contaminated during 1 h, 24 h and 30 days. Long term sorption kinetics indicated that the difference between sorption occurring during the period 0-30 days (time investigated in this study) and the period 0-48 h (time often used for sorption experiments) ranges from few to 25% according to the element. Desorption kinetics show that, whatever the age of the complex formed during the sorption step, the release tends to equilibrium between complexed and dissolved elements equivalent to the equilibrium obtained for sorption after a given time. However, the time to get this equilibrium depends on the aging of the complex and on the element. All the above features indicate different types of complexes formation and strength of the binding according to the age of the complex and according to the element. Using a multi-compartmental model, simulating the transfer of metals between water and different types of particulate sites, the relationships between the parameters describing slow and rapid processes helped in explaining the "aging" effect observed. 相似文献
93.
Variations of sediment type (grain size and refractive index) and changing illumination conditions affect the reflectance signal of coastal waters and limit the accuracy of sediment-concentration estimations from remote-sensing measurements. These effects are analyzed from numerous in situ remote-sensing measurements carried out in the Gironde and Loire Estuaries and then reduced and partly eliminated when reflectance ratios between the near infrared and the visible are considered. These ratios showed high correlation with the sediment concentration. On the basis of the obtained relationships, performing correspondence functions were established that allow an accurate estimation of suspended sediments in the estuaries from Système Probatoire d'Observation de la Terre, Landsat, and Sea-Viewing Wide Field-of-View Sensor data, independently of the date of acquisition. 相似文献
94.
Modern information systems rely more and more on combining concurrent, distributed, mobile and heterogenous components. This move from old systems, typically conceived in isolation, induces the need for new languages and software architectures. In particular, coordination languages have been proposed to cleanly separate computational aspects and communication. On the other hand, software architects face the problem of specifying and reasoning about non-functional requirements. All these issues are widely perceived as fundamental to improve software productivity, to enhance maintainability, to advocate modularity, to promote reusability, and to lead to systems more tractable and more amenable to verification and global analysis.The FOCLASA workshop was organized on August 24th 2002 as a satellite event of Concur'02 with the aim of bringing together researchers working on the foundations of component-based computing, coordination, and software architectures.This volume contains selected 12 papers presented at the workshop. They were reviewed by the program committee, consisting, besides the editors, of
- • Rocco De Nicola (University of Firenze, Italy)
- • Jos Luiz Fiadeiro (ATX Software and University of Lisbon, Portugal)
- • Roberto Gorrieri (University of Bologna, Italy)
- • Paola Inverardi (University L'Aquila, Italy)
- • Joost Kok (University of Leiden, The Netherlands)
- • Antonio Porto (New University of Lisbon, Portugal)
95.
Eva Ploux Valentine Bouet Inna Radzishevsky Herman Wolosker Thomas Freret Jean-Marie Billard 《International journal of molecular sciences》2020,21(24)
d-serine is the major co-agonist of N-methyl-D-aspartate receptors (NMDAR) at CA3/CA1 hippocampal synapses, the activation of which drives long-term potentiation (LTP). The use of mice with targeted deletion of the serine racemase (SR) enzyme has been an important tool to uncover the physiological and pathological roles of D-serine. To date, some uncertainties remain regarding the direction of LTP changes in SR-knockout (SR-KO) mice, possibly reflecting differences in inhibitory GABAergic tone in the experimental paradigms used in the different studies. On the one hand, our extracellular recordings in hippocampal slices show that neither isolated NMDAR synaptic potentials nor LTP were altered in SR-KO mice. This was associated with a compensatory increase in hippocampal levels of glycine, another physiologic NMDAR co-agonist. SR-KO mice displayed no deficits in spatial learning, reference memory and cognitive flexibility. On the other hand, SR-KO mice showed a weaker LTP and a lower increase in NMDAR potentials compared to controls when GABAA receptors were pharmacologically blocked. Our results indicate that depletion of endogenous D-serine caused a reduced inhibitory activity in CA1 hippocampal networks, altering the excitatory/inhibitory balance, which contributes to preserve functional plasticity at synapses and to maintain related cognitive abilities. 相似文献
96.
Gisele Boiteux-Steffan Jean-Pierre Soulie Daniel Sage Jean-Marie Letoffé 《Polymer》1985,26(10):1443-1447
Polyallylbenzene is a semicrystalline material the thermal behaviour and physical properties of which reveal several transitions. Thermal and differential calorimetric analysis have shown the influence of the history of the material about the glass transition and melting. Several techniques such as thermomechanical analysis, dilatometry and inverse gas chromatography give additional information for the unidimensional and volume behaviour of the polymer versus temperature. 相似文献
97.
Bouchard Stéphane; Bolduc Daniel; Boisvert Jean-Marie; Gauthier Janel 《Canadian Metallurgical Quarterly》1995,36(3):190
Reviews the literature on the impact of interpersonal relationships, especially family relationships, on the development, maintenance, and behavioral treatment of agoraphobia. Interpersonal relationships seem to play some role in the agoraphobic pathology, mainly for the onset of agoraphobia and the presence of social anxiety. However, it seems that its importance is less than what has been suggested in the literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
99.
Rizzo Lydia; Danion Jean-Marie; Van Der Linden Martial; Grangé Danielle; Rohmer Jean-Georges 《Canadian Metallurgical Quarterly》1996,10(3):376
A group of 33 patients with schizophrenia were compared with control participants using a spatial memory task in which words were presented on locations of a grid. In the first part of the experiment, recognition of target information (words) was tested. In the second, 2 tasks of spatial location (contextual information) were given involving different sets of words placed in different locations: A location memory task (determining which word was in a particular spatial location) explored an associative form of spatial memory, and a relocation task (determining where a particular word was located) explored an associative and a nonassociative form of spatial memory. Patients were more impaired with regard to the location memory task than to the target recognition and relocation tasks. The impairment was negatively correlated with Stroop task performance. The results suggest that schizophrenia is associated with a spatial context memory deficit, which could be due to defective associations between target and spatial information. This deficit seemed to be related to frontal dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Jean-Marie R. Génin 《Metallurgical and Materials Transactions A》1988,19(12):2901-2909
The clustering of carbon atoms into isolated multiplets followed by their ordering into (100)α’ mono-layers leads to the B2 monoclinic multilayer structure called the extended multiplet, during the low temperature aging of Fe-C martensite. The ultimate step of the process is obtained by a lC,2Fe, lC,5Fe, lC,5Fe sequence along the [001]α′. direction giving rise to a 12 lattice parameter periodicity associated with antiphase domains, for matching the lattices of the precipitate and of the matrix. It explains the satellites observed by electron diffraction as well as the (023)α′. habit plane revealed by the diffuse scattering streaks and TEM observations. The carbon free regions between the antiphase domains correspond to the ‘C ’ or ‘к’ phase as determined from the (200)/(020) and (002) martensite peak profile X-ray analysis. The laterin situ transformation to the ordered Fe9C4 ε- or η-carbide, corresponds to an orthorhombic structure with parametersα η =3α ε,b η≈ 3αε√3, andc η =c ε, ifα ε andcε are the initial parameters of the Fe hcp stacking,i.e., α η= 8.46 to 8.49 Å,b η = 14.04 to 14.07 Å, andc η = 4.31 to 4.32 Å for the binary Fe-C alloys. The transformation induces plate-like carbide precipitates with a (035)(gα′). predicted habit plane, which is 4.40 deg away from the approximate (012)ga′. plane observed by TEM. 相似文献