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61.
本文报导了采用一种新型高温陶瓷发热体高温管状炉,通以氩气保护,测量WRe合金丝的电阻-温度(1600℃)特性试验方法,该方法较真空炉简便、实用且试验费用低而准确,测量数据与美国研究报导一致。 相似文献
62.
Marco Dalai Author Vitae 《Automatica》2007,43(8):1418-1425
In this paper we consider the problem of constructing confidence regions for the parameters of nonlinear dynamical systems. The proposed method uses higher order statistics and extends the LSCR (leave-out sign-dominant correlation regions) algorithm for linear systems introduced in Campi and Weyer [2005, Guaranteed non-asymptotic confidence regions in system identification. Automatica 41(10), 1751-1764. Extended version available at 〈http://www.ing.unibs.it/∼campi〉]. The confidence regions contain the true parameter value with a guaranteed probability for any finite number of data points. Moreover, the confidence regions shrink around the true parameter value as the number of data points increases. The usefulness of the proposed approach is illustrated on some simple examples. 相似文献
63.
The change in the internal energy during uniaxial tensile deformation of austenitic stainless steels EN 1.4301 (AISI 304) and EN 1.4318 (AISI 301LN) was determined by measuring the extent of γ→α'‐martensite transformation and the temperature increase of the samples. From the results the fraction of the stored energy of cold work and the free energy change related to the strain‐induced γ→α'‐martensite transformation were determined. The fraction of stored energy varied around 0.4. With the metastable steel grades the free energy change related to the γ→α'‐martensite transformation was found to vary between ‐98 MJ/m3 and ‐206 MJ/m3 depending on the austenite stability of the steel. Furthermore, the magnitude of the mechanical driving force was estimated by comparing the results with the free energy change of thermally induced transformation. 相似文献
64.
66.
Phase-change thermal energy storage using spherical capsules: performance of a test plant 总被引:1,自引:0,他引:1
J.P Bédécarrats F Strub B Falcon J.P Dumas 《International Journal of Refrigeration》1996,19(3):187-196
The aim of this paper is the study of an industrial process of energy storage usable for air conditioning or refrigeration, investigating a test plant which is a tank with a reduced size, filled with randomly dispersed commercial nodules, placed in a refrigeration loop. The nodules are spherical capsules in which phase change materials (PCM) are encapsulated. This test plant permits the study at length of the behaviour of the tank with, in particular, the charge mode taking into account the undercooling and the discharge mode. A simulation program that considers aspects of both the surrounding heat transfer fluid and the phase-change material packed inside the nodules is developed here in the cases of the charge and the discharge processes. The simulation results are then compared with experimental observations. 相似文献
67.
鄂钢140 t/h干熄焦秉承国产化干熄焦技术优点,同时具有多项技术创新,并对工艺和设备进行技术改进和完善。生产稳定,效益明显。 相似文献
68.
It is stated in the above-mentioned comment that the main result of the paper Xiong, Zhang, et al. [(2006). Performance evaluation of UKF-based nonlinear filtering. Automatica 42(2), 261-270] can be extended to a class of filters, such as the extended Kalman filter (EKF). As we show here, this belief can be justified in a rigorous way, even for the nonlinear stochastic system with a nonlinear measurement equation. 相似文献
69.
Jonas Sjberg Qinghua Zhang Lennart Ljung Albert Benveniste Bernard Delyon Pierre-Yves Glorennec Hkan Hjalmarsson Anatoli Juditsky 《Automatica》1995,31(12):1691-1724
A nonlinear black-box structure for a dynamical system is a model structure that is prepared to describe virtually any nonlinear dynamics. There has been considerable recent interest in this area, with structures based on neural networks, radial basis networks, wavelet networks and hinging hyperplanes, as well as wavelet-transform-based methods and models based on fuzzy sets and fuzzy rules. This paper describes all these approaches in a common framework, from a user's perspective. It focuses on what are the common features in the different approaches, the choices that have to be made and what considerations are relevant for a successful system-identification application of these techniques. It is pointed out that the nonlinear structures can be seen as a concatenation of a mapping form observed data to a regression vector and a nonlinear mapping from the regressor space to the output space. These mappings are discussed separately. The latter mapping is usually formed as a basis function expansion. The basis functions are typically formed from one simple scalar function, which is modified in terms of scale and location. The expansion from the scalar argument to the regressor space is achieved by a radial- or a ridge-type approach. Basic techniques for estimating the parameters in the structures are criterion minimization, as well as two-step procedures, where first the relevant basis functions are determined, using data, and then a linear least-squares step to determine the coordinates of the function approximation. A particular problem is to deal with the large number of potentially necessary parameters. This is handled by making the number of ‘used’ parameters considerably less than the number of ‘offered’ parameters, by regularization, shrinking, pruning or regressor selection. 相似文献
70.