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排序方式: 共有166条查询结果,搜索用时 15 毫秒
91.
The paper presents numerical simulations of heat conduction around a circular vertical cylinder immersed in liquids. A finite volume formulation is used, and the numerical analysis is performed in unsteady state with an explicit scheme. The numerical predictions are compared with experiments performed on liquids to find the temperature inside the cylinder, where a thermocouple is located, and at the wall of the insulated coaxial container, where the liquid is poured. The cylinder is immersed vertically. The numerical results are in good agreement with the temperature at the wall of the container. The experimental temperature measurement of the thermocouple located inside the probe is intermediate between the numerical temperatures on the axis and on the surface of the probe. The natural convection phenomenon is evidenced in the experiments, after a certain time from the beginning of heating, in some of the liquids used, except glycerol. Natural convection is not considered in the present numerical simulations, which solve only the heat conduction equation.  相似文献   
92.
The prediction of the linguistic origin of surnames is a basic functionality required in the design of high-quality multilanguage speech synthesizers. The assignment of a given string representing a surname to a specific language is typically based on a set of rules which can hardly be written in an explicit form. The approach we propose faces this problem combining a rule-based system with a module based on evidential reasoning and a module based on neural networks. The resulting hybrid system combines the different sources of information, merging both knowledge from experts on linguistics and knowledge automatically acquired using learning from examples. The system has been validated on a large database containing surnames belonging to four different languages, showing its effectiveness for real-world applications.  相似文献   
93.
The electrical resistivity (ER) of Flexinol nickel-titanium shape memory alloys (SMA) has been measured in the range from −15 to 105°C. The investigated Flexinol wires have two diameters, 150 and 375 μm. The experimental results show new temperatures of phase transformation (TTR) evidencing the unexpected presence of the R-phase. The transformations from austenite to martensite, from austenite to R-phase, and vice versa are simultaneous. In the range [20 to 110°C] the hysteresis is almost negligible, whereas in the range [−15 to 105°C] the accommodation process of the hysteresis is observed.  相似文献   
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Toussaint UV  Gori S  Dose V 《Applied optics》2004,43(28):5356-5363
We present a new method using Bayesian probability theory and neural networks for the evaluation of speckle interference patterns for an automated analysis of deformation and erosion measurements. The method is applied to the fringe pattern reconstruction of speckle measurements with a Twyman-Green interferometer. Given a binary speckle image, the method returns the fringe pattern without noise, thus removing the need for smoothing and allowing a straightforward unwrapping procedure and determination of the surface shape. Because no parameters have to be adjusted, the method is especially suited for continuous and automated monitoring of surface changes.  相似文献   
97.
Effects of cold maceration on red wine quality from Tuscan Sangiovese grape   总被引:1,自引:0,他引:1  
Pre-fermentation cold maceration of must by the direct addition of two cryogens was studied. The experiments were conducted on Sangiovese grape from a typical Chianti vineyard in the year 2001 with two cryogens (solid state carbon dioxide and liquid nitrogen) and at various temperatures (from –5 to +5 °C) in 500-L batches for 48 h. The wines obtained were characterized by chemical analyses and sensory evaluation, and higher quality resulted as seen from the analytical and sensory characteristics with higher extraction of polyphenolic compounds at lower cold maceration temperature. Liquid nitrogen was more effective than solid carbon dioxide at the same temperature. Proportional increase of wine quality with lower cold maceration temperature was observed for solid carbon dioxide. Further investigation is needed to establish the management protocol, a proper engineering of this technique, and to evaluate its economical advantages.  相似文献   
98.
Acoustic modeling in state-of-the-art speech recognition systems usually relies on hidden Markov models (HMMs) with Gaussian emission densities. HMMs suffer from intrinsic limitations, mainly due to their arbitrary parametric assumption. Artificial neural networks (ANNs) appear to be a promising alternative in this respect, but they historically failed as a general solution to the acoustic modeling problem. This paper introduces algorithms based on a gradient-ascent technique for global training of a hybrid ANN/HMM system, in which the ANN is trained for estimating the emission probabilities of the states of the HMM. The approach is related to the major hybrid systems proposed by Bourlard and Morgan and by Bengio, with the aim of combining their benefits within a unified framework and to overcome their limitations. Several viable solutions to the "divergence problem"-that may arise when training is accomplished over the maximum-likelihood (ML) criterion-are proposed. Experimental results in speaker-independent, continuous speech recognition over Italian digit-strings validate the novel hybrid framework, allowing for improved recognition performance over HMMs with mixtures of Gaussian components, as well as over Bourlard and Morgan's paradigm. In particular, it is shown that the maximum a posteriori (MAP) version of the algorithm yields a 46.34% relative word error rate reduction with respect to standard HMMs.  相似文献   
99.
Triple‐junction GaInP/GaAs/GaInNAs solar cells with conversion efficiency of ~29% at AM0 are demonstrated using a combination of molecular beam epitaxy (MBE) and metal‐organic chemical vapor deposition (MOCVD) processes. The bottom junction made of GaInNAs was first grown on a GaAs substrate by MBE and then transferred to an MOCVD system for subsequent overgrowth of the two top junctions. The process produced repeatable cell characteristics and uniform efficiency pattern over 4‐inch wafers. Combining the advantages offered by MBE and MOCVD opens a new perspective for fabrication of high‐efficiency tandem solar cells with three or more junctions. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
100.
介绍了达涅利先进的中型和大型型钢轧制工艺和设备。主要包括:PSP型钢定径轧制工艺,SCC(机芯概念)机架,轧机准备区,以及最近安装的设备和最新的轧机订单等。  相似文献   
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