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11.
Research supported in part by NSF Grant No. DMS-9107372 相似文献
12.
Meraz Mónica González-Barrera Alfonso Alvarez-Ramirez José Monroy Oscar 《Applied biochemistry and biotechnology》1996,57(1):525-534
Applied Biochemistry and Biotechnology - In this article, a study of the dynamics of the immobilization of mesophilic anaerobic bacteria was conducted. Low-density polyethylene (LDPE) ground to... 相似文献
13.
This paper considers an airline crew allocation and scheduling problem faced by certain divisions of the United States Air Force. Two variants of the problem under consideration were posed to us by the U.S. Air Force. This paper reports our experience with two heuristic methods developed, each applicable to either variant of the problem. Although the problem described herein is peculiar to this situation, the heuristic scheduling and dispatching rules developed have been found to be very effective and are generally applicable in other related contexts of routeing and crew and vehicle scheduling problems as well. The two algorithms developed have been applied to a coded set of real world data. The results indicate that each one of the two methods is preferable to the other for one of the two variants of the problem. This suggests an overall effective composite technique. 相似文献
14.
M.?A.?Hinojosa A.?M.?MármolEmail author L.?Monroy 《Annals of Operations Research》2005,137(1):243-255
In this paper we address bargaining games where the agents have to take into account different criteria to value the decisions.
We propose the class of generalized maximin solutions, as the natural extension for these games of the maximin solutions in
conventional bargaining. In order to refine this solution concept, we define a multicriteria lexicographic partial ordering
and present the class of generalized leximin solutions as those that are nondominated with respect to this relation. We establish
some properties of these solutions and characterize them as solutions of multicriteria problems.
The research of the authors is partially supported by the Spanish Ministry of Science and Technology projects BFM2002-11282-E
and BEC2003-03111. 相似文献
15.
L. Doyennette A. Vardi F. Guillot L. Nevou M. Tchernycheva A. Lupu R. Colombelli G. Bahir E. Monroy F.H. Julien 《Superlattices and Microstructures》2006,40(4-6):262
We have demonstrated GaN/AlN quantum dots (QD) photodetectors, relying on intraband absorption and in-plane carrier transport in the wetting layer. The devices operate at room temperature in the wavelength range 1.3–1.5 μm. Samples with 20 periods of Si-doped GaN QD layers, separated by 3 nm-thick AlN barriers, have been grown by plasma-assisted molecular-beam epitaxy on an AlN buffer on a c-sapphire substrate. Self-organized dots are formed by the deposition of 5 monolayers of GaN under nitrogen-rich conditions. The dot height is 1.2±0.6 to 1.3±0.6 nm and the dot density is in the range 1011–1012 cm−2. Two ohmic contacts were deposited on the sample surface and annealed in order to contact the buried QD layers. The dots exhibit TM polarized absorption linked to the s–pz transition. The photocurrent at 300 K is slightly blue-shifted with respect to the s–pz intraband absorption. The responsivity increases exponentially with temperature and reaches a record value of 10 mA/W at 300 K for detectors with interdigitated contacts. 相似文献
16.
GA Méndez-Maldonado M González-Melchor J Alejandre 《The Journal of chemical physics》2012,137(5):054711
Direct molecular dynamics simulations on interfaces at constant temperature are performed to obtain the liquid-vapor phase diagram of the two-dimensional soft primitive model, an equimolar mixture of equal size spheres carrying opposite charges. Constant temperature and pressure simulations are also carried out to check consistency with interface simulations results. In addition, an analysis of the cluster formation of mixtures of particles with charge asymmetry in the range 1:1 to 1:36 at low and high densities is performed. The number of free ions, when plotted as a function of the positive ion charge, Z(+), has an oscillatory behavior and is independent of the density. The formation of aggregates is analyzed in terms of the attraction and repulsion between ions. 相似文献
17.
AlGaN-based UV photodetectors 总被引:6,自引:0,他引:6
E. Monroy F. Calle J. L. Pau E. Mu oz F. Omn s B. Beaumont P. Gibart 《Journal of Crystal Growth》2001,230(3-4):537-543
AlxGa1−xN alloys are very attractive materials for application to ultraviolet photodetection. AlGaN photoconductors, Schottky photodiodes, metal–semiconductor–metal photodiodes, p–n junction photodetectors and phototransistors have been recently developed. In this work we analyse the performance of AlGaN-based photodetectors, discussing present achievements, and comparing the characteristics of the various photodetector structures developed to date. 相似文献
18.
The surface pressure (Π) vs surface concentration (Γs) curves of the hydrogen-bonded polymer blend poly(vinylacetate)+ poly(4-hydro-xystyrene) (PVAc+P4HS) have been measured at
25 °C onto a water subphase at pH=2.0. While PVAc forms extended monolayers, and the free surface of water is found to be
a good solvent for it, P4HS forms compressed monolayers, and the surface is a near Θ-type solvent for it. PVAc and P4HS form
miscible non-ideal monolayers until near the collapse pressure through the whole concentration range. The composition dependence
of the Π–Γs curves is rather complex. Contrary to what might be expected, the addition of PVAc to the blend does not reduce the rigidity
of the monolayer until its weight fraction is larger than 0.5. The compressibility data of the P4HS-rich monolayers suggest
the existence of a second maximum at high surface coverages, a result already observed in some polysiloxanes.
Received: 11 March 1998 Accepted: 7 May 1998 相似文献
19.
Velázquez MM Ortega F Monroy F Rubio RG Pegiadou S Pérez L Infante MR 《Journal of colloid and interface science》2005,283(1):144-152
We report the formation of Langmuir monolayers of pure zwitterionic hexadecyl 1-N-L-tryptophan glycerol ether (C(16)-TGE) surfactant and mixed monolayers of cationic-zwitterionic surfactant obtained modifying the pH of the subphase. The pressure-area and surface potential-area isotherms and fluorescence microscopy measurements have been used to characterize the surface phase transitions in the monolayers. These transitions appeared at larger areas as the pH decreased from 6.0 to 2.0 and almost disappeared as the pH decreased further. The analysis of the surface potential and the infrared reflection-absorption spectroscopy data suggests that the phase transition is associated with a change of orientation of both the hydrocarbon chain and the aromatic group of the surfactant with respect to the air-water surface. The surface rheology of the monolayers was studied by quasielastic light scattering and by the oscillatory barrier technique. The results indicate that there is at least one relaxation process in the monolayer. 相似文献
20.
Two-dimensional (2-D) gel electrophoresis has been used to follow changes in cell type specific and organelle localized polypeptides upon exposure of etiolated sorghum shoots and dark-grown resting Euglena to light. Total protein extracted from isolated bundle sheath strands and mesophyll protoplasts was resolved by 2-D gel electrophoresis. The cell type specific polypeptides were localized on the whole shoot 2-D gel map in order to determine changes in the levels of these polypeptides upon light exposure. An image analyzer was used to analyze fluorographs of 2-D gels of total Euglena protein pulse-labeled with [35S]sulfate in the dark, immediately upon light exposure and 1, 4, 14, 24, 48 and 72 h after light exposure. The subset of polypeptides whose relative rate of synthesis changes more than threefold immediately upon light exposure was identified. The different patterns of changes in the rate of synthesis of this subset of polypeptides were followed. 相似文献