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21.
22.
This paper presents results of the effect of electron beam irradiation under UHV conditions on InGaAs/GaAs and GaAsN/GaAs systems using Auger electron spectroscopy (AES) and the electron energy loss spectroscopy (EELS) as surface analytical techniques. The ternary compounds In0.53Ga0.47As and In0.2Ga0.8As were irradiated by an electron beam under identical conditions (5 KeV; 10−3 A cm−2; for 60 min). The results showed that the compound In0.53Ga0.47As was stable under electron irradiation whereas changes in the Auger signal In-M45N45N45 revealed that the electron beam had a significant effect on the compound In0.2Ga0.8As. GaAsN growth at 590 °C on GaAs is believed to produce a surface containing defects that is chemically unstable when bombarded by electrons. It was found that heating this compound at 730 °C stabilised the surface, protecting it from the effect of electron irradiation. 相似文献
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24.
In this paper, we present a nonlinear model based dynamic optimization approach for optimal control for thermo-mechanical pulping (TMP) processes. The method is based on nonlinear model predictive control (NMPC) technique with an economic objective function. In our previous work [1], an economically oriented NMPC (econNMPC) was presented for a two-stage TMP process with high consistency (HC) refiners. The two-stage TMP process was simulated up to the secondary refiner. In this study, we extend the previous study to multiple stages that include low consistency (LC) refining. Here we can exploit the complexity of interactions of multiple stage TMP for both performance and optimal operations. The first process is a conventional refining process with two stages of HC refining with a primary and a secondary refiner, followed by a latency chest and a third-stage LC refiner. The second TMP process has only a HC primary refiner, and the secondary stage HC refiner is replaced by multiple stages of LC refiners after the latency chest. Both TMP schemes are dynamically optimized against disturbances to produce the same target final pulp qualities while minimizing specific energy consumption of the processes. The simulation results show the potential economic benefits of the proposed method, through a reduction in total specific energy, about 24%, for the second TMP process. 相似文献
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26.
Calin Glitia Philippe Dumont Pierre Boulet 《Multidimensional Systems and Signal Processing》2010,21(2):105-131
Intensive signal processing applications appear in many application domains such as video processing or detection systems.
These applications handle multidimensional data structures (mainly arrays) to deal with the various dimensions of the data
(space, time, frequency). A specification language allowing the direct manipulation of these different dimensions with a high
level of abstraction is a key to handling the complexity of these applications and to benefit from their massive potential
parallelism. The Array-OL specification language is designed to do just that. We introduce here an extension of Array-OL to
deal with states or delays by the way of uniform inter-repetition dependences. We show that this specification language is
able to express the main patterns of computation of the intensive signal processing domain. 相似文献
27.
28.
Starting three weeks before mating, 12 groups of female rats were fed different amounts of linoleic acid (18∶2n−6). Their
male pups were killed when 21-days-old. Varying the dietary 18∶2n−6 content between 150 and 6200 mg/100 g food intake had
the following results. Linoleic acid levels remained very low in brain, myelin, synaptosomes, and retina. In contrast, 18∶2n−6
levels increased in sciatic nerve. In heart, linoleic acid levels were high, but were not related to dietary linoleic acid
intake. Levels of 18∶2n−6 were significantly increased in liver, lung, kidney, and testicle and were even higher in muscle
and adipose tissue. On the other hand, in heart a constant amount of 18∶2n−6 was found at a low level of dietary 18∶2n−6.
Constant levels of arachidonic acid (20∶4n−6) were reached at 150 mg/100 g diet in all nerve structures, and at 300 mg/100g
diet in testicle and muscle, at 800 mg/100 g diet in kidney, and at 1200 mg/100 g diet in liver, lung, and heart. Constant
adrenic acid (22∶4n−6) levels were obtained at 150, 900, and 1200 mg/100 g diet in myelin, sciatic nerve, and brain, respectively.
Minimal levels were difficult to determine. In all fractions examined accumulation of docosapentaenoic acid (22∶5n−6) was
the most direct and specific consequence of increasing amounts of dietary 18∶2n−6. Tissue eicosapentaenoic acid (20∶5n−3)
and 22∶5n−3 levels were relatively independent of dietary 18∶2n−6 intake, except in lung, liver, and kidney. In several organs
(muscle, lung, kidney, liver, heart) as well as in myelin, very low levels of dietary linoleic acid led to an increase in
20∶5n−3. Dietary requirements for 18∶2n−6 varied from 150 to 1200 mg/100 g food intake, depending on the organ and the nature
of the tissue fatty acid. Therefore, the minimum dietary requirement is estimated to be about 1200 mg/100 g (i.e., the level
that ensures stable and constant amounts of arachidonic acid). 相似文献
29.
Yorick Reyjol Philippe Brodeur Yves Mailhot Marc Mingelbier Pierre Dumont 《Journal of Great Lakes research》2010
We evaluated whether or not the invasive round goby (Neogobius melanostomus) represents an important prey source for seven native fish predators in Lake St. Pierre (St. Lawrence River, Canada). The frequency of occurrence of round goby in the stomach contents of brown bullhead (Ameiurus nebulosus) and channel catfish (Ictalurus punctatus) was very low (< 5%), while for the five other predators, it varied between 22% (yellow perch; Perca flavescens) and 65% (sauger; Sander canadensis). Several competing models linking the probability of occurrence of round goby in stomach contents to variables related to space, physical habitat, biotic interactions and predator size were tested for the five species feeding on round goby. Results indicated that space variables influenced round goby occurrence in stomachs for all species. In addition, physical habitat variables had an influence for sauger and walleye (Sander vitreus); biotic variables had an influence for yellow perch, walleye and sauger; and size had an influence for northern pike (Esox lucius), smallmouth bass (Micropterus dolomieu) and walleye. These results are discussed in light of known biological features of the round goby and native predators studied here and have important implications in terms of understanding round goby invasion success in the Great Lakes–St. Lawrence system. 相似文献
30.
Nicolas Pronost Georges Dumont Gilles Berillon Guillaume Nicolas 《The Visual computer》2006,22(1):4-13
We present a computer tool for testing walk hypotheses for human beings. This tool aims to generate plausible walking movements
according to anatomical knowledge. To this end, we introduce an interpolation method based, on one hand, on morphological
data and, on the other hand, on stance hypotheses and on footprint hypotheses. We want to test these hypotheses for application
to the reconstruction of early hominid walking. We interpolate from a specific representation of the movement—a characteristic
relative displacement. First, we use a motion capture system to acquire real movements of a walk cycle, and we propose to
represent them by using a generic parametric model. Thus, we create a database of movements. The interpolation process produces,
thanks to this database, a retargeted motion adapted to the morphology of the considered targeted skeleton. The interpolation
is done according to three main hypotheses. The first concerns the reference stance, the second the lateral spacing between
the feet, and the third the length of the step. In the introduction, we refer to related work. Then we propose the two following
points of our method: the 3D representation of our motion representation and the multidimensional interpolation method applied
to this representation. The interpolation method addresses morphological adaptation, and the use of an inverse kinematics
solver addresses the computation of skeleton movements. The self-coherent validation process aims to test the coherence of
the proposed method. The results propose an application to a virtual skeleton of Lucy (Australopithecus afarensis A.L. 288-1) reconstructed from real data. Finally, the relevance of the method for anthropological investigations and for
animation purposes is discussed and future work is discussed with respect to the limitations of the proposed method. 相似文献