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排序方式: 共有320条查询结果,搜索用时 15 毫秒
1.
A numerical model of solar cells is described, which provides optimum design rules for exponential N+ dopant profiles for heavily doped emitter regions. The model gives a useful insight into the relative impact of surface and bulk recombination on device performance. Results agree well with theorical models. 相似文献
2.
Exposito A.G. Soler A.B. Macias J.A. 《IEEE transactions on circuits and systems. I, Regular papers》2006,53(7):1533-1543
This paper focuses on the natural response computation of linear time-invariant (LTI) circuits, in those cases in which a closed-form solution, rather than numerical integration of the state-variable equations, is preferable. A computationally efficient procedure is presented to individually obtain the eigenvectors of matrix A, both for distinct and repeated eigenvalues. Instead of performing orthogonal matrix transformations, the proposed method relies on the solution of the nodal equations corresponding to a zero-input circuit in the generalized phasor domain. This allows propagation of natural modes to be computed by means of a simple procedure that closely resembles conventional ac analysis. 相似文献
3.
Jesú s Guardiola Soler Juan J. Prieto Marqu s M nica Garcí a Ruiz Guadalupe Ramos Caicedo 《Chemical Engineering Communications》2003,190(3):285-298
The purpose of the present work is to demonstrate the reliability of a digital image processing technique. A CCD (Charge Coupled Device) is used to perform an investigation on the bubble properties of a 2D gas-solid fluidized bed, and the aim of this study is to establish a criterion in order to reject all images that could not be interpreted as bubbles. This may lead to an alteration of the information obtained. The two-dimensional fluidized bed is 20 cm wide and at least 20 cm high, and the field of view of the camera is 12.54 cm wide and 12.99 cm high. In this way, bubbles could be totally or partially placed into this field of view so that a partial image of a bubble could be analyzed as a whole bubble. With this calibration, a geometric decision criterion for the rejection of nonbubble images was developed. 相似文献
4.
5.
Xavier Desforges Abdallah Habbadi Laurent Geneste François Soler 《Journal of Intelligent Manufacturing》2004,15(1):39-53
The study of smart sensors and actuators led, during the past few years, to the development of facilities which improve traditional sensors and actuators in a necessary way to automate production systems. In another context, many studies have been carried out aimed at defining a decisional structure for production activity control and the increasing need of reactivity leads to the autonomization of decisional levels close to the operational system. We study in this paper the natural convergence between these two approaches and we propose an integration architecture, dealing with machine tool and machining control, that enables the exploitation of distributed smart sensors and actuators in the decisional system. 相似文献
6.
Antonio Martı́nez Chaparro Jaime Soler Maria José Escudero Loreto Daza 《Fuel Cells Bulletin》2003,2003(11):10-12
Photovoltaic systems are widely used to power telecommunications systems in remote locations, but this is restricted by the irregular availability of solar energy. A European collaboration is developing and testing an autonomous system that combines a photovoltaic power system in combination with an electrolyzer that uses surplus power to produce hydrogen, which can be used in a PEM fuel cell when there is insufficient solar energy. 相似文献
7.
AbstractA system methodology for modeling and optimizing social systems is presented. It allows constructing dynamical models formulated stochastically, i.e., their results are given by confidence intervals. The models provide optimal intervention ways to reach the stated objectives. Two optimization methods are used: (1) to test strategies and scenarios and (2) to optimize with a genetic algorithm. The application case presented is a small nonformal education Spanish business. First, the model is validated in the 2008–2012 period, and subsequently, the optimal way to obtain a maximum profit in the 2013–2025 period is obtained using the two methods. 相似文献
8.
Sâmya Soler Gebara Wellyta de Oliveira Ferreira Nilva Ré-Poppi Euclésio Simionatto Eduardo Carasek 《Food chemistry》2011
Volatile compounds present on fruits and leaves of Mangifera indica var. coquinho were investigated by headspace solid phase microextraction (HS-SPME) and hydrodistillation (HD). Conventional techniques, such as hydrodistillation, may impart chemical changes to the original oil composition being also time-consuming. On the other hand, HS-SPME provides solvent-less extractions, shorter extraction times and may supply complementary information about the composition of the compounds. The HS-SPME technique was previously evaluated by the comparative study among the fibres: commercial PDMS, NiTi-ZrO2 and NiTi-ZrO2-PDMS. The fibre NiTi-ZrO2-PDMS showed better sensitivity and precision and was used on the extraction of components. The influence of several parameters like the time and temperature of extraction and desorption time were examined to obtain better efficiency. Fruits and leaves were analysed in mature and immature stages. The profiles corresponding to the volatile compounds detected by both techniques are discussed. 相似文献
9.
Characterisation of Aeromonas spp. isolated from frozen fish intended for human consumption in Mexico 总被引:2,自引:0,他引:2
Castro-Escarpulli G Figueras MJ Aguilera-Arreola G Soler L Fernández-Rendón E Aparicio GO Guarro J Chacón MR 《International journal of food microbiology》2003,84(1):41-49
A total of 82 strains of presumptive Aeromonas spp. were identified biochemically and genetically (16S rDNA-RFLP). The strains were isolated from 250 samples of frozen fish (Tilapia, Oreochromis niloticus niloticus) purchased in local markets in Mexico City. In the present study, we detected the presence of several genes encoding for putative virulence factors and phenotypic activities that may play an important role in bacterial infection. In addition, we studied the antimicrobial patterns of those strains. Molecular identification demonstrated that the prevalent species in frozen fish were Aeromonas salmonicida (67.5%) and Aeromonas bestiarum (20.9%), accounting for 88.3% of the isolates, while the other strains belonged to the species Aeromonas veronii (5.2%), Aeromonas encheleia (3.9%) and Aeromonas hydrophila (2.6%). Detection by polymerase chain reaction (PCR) of genes encoding putative virulence factors common in Aeromonas, such as aerolysin/hemolysin, lipases including the glycerophospholipid-cholesterol acyltransferase (GCAT), serine protease and DNases, revealed that they were all common in these strains. Our results showed that first generation quinolones and second and third generation cephalosporins were the drugs with the best antimicrobial effect against Aeromonas spp. In Mexico, there have been few studies on Aeromonas and its putative virulence factors. The present work therefore highlights an important incidence of Aeromonas spp., with virulence potential and antimicrobial resistance, isolated from frozen fish intended for human consumption in Mexico City. 相似文献
10.