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61.
节流式差压流量计的发展和现状 总被引:2,自引:0,他引:2
文章介绍节流式差压流量计的特点及标准化进程,煤气流量测量中存在的难点以及正在试图解决的途径。 相似文献
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Yubin Yang Hui Lin Jixi Jiang 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2006,36(1):162-172
This paper presents a computer-aided cloud-analysis approach by effectively modeling the integration of heterogeneous satellite-observed data and remote sensing images. First, automatic cloud detection and tracking methods are proposed to identify the georeferenced cloud objects in satellite remote sensing images. Then, a data integration modeling mechanism is designed to collect meaningful properties of those detected clouds by integrating the heterogeneous satellite-observed data and imaging into a unified cloud database. Finally, based on the integrated global data schema, a two-phase data mining method employing the decision tree algorithm is implemented to analyze and forecast the meteorological activities of all the cloud objects. Experimental results have shown that the proposed data integration model can effectively extract and synthesize all the useful information from heterogeneous data sources to generate a unified view of knowledge, on the basis of which the evolvement trends of clouds can be analyzed properly. 相似文献
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Lee C.K. Hui S.Y.R. Shu-HungChung H. Shrivastava Y. 《Power Electronics, IEEE Transactions on》2002,17(1):94-100
In this paper, a feasibility study of a randomized space vector switching scheme for three-level inverters is reported. Based on the traditional space vector concept for pulse width modulation (PWM) inverters, the sequence of the space vector is randomized in this scheme. The overall vector, resulting from the randomization, is mathematically identical to that of the traditional space vector. It has been found that the randomized scheme can effectively spread the switching noise over a wide frequency range and at the same time keep the steady-state link capacitor voltage balanced. The proposed scheme has been implemented in real time in a digital controller and its features have been experimentally confirmed 相似文献
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In-phase(IP) and out-of-phase(OP)thermal-mechanical fatigue(TMF) behavior of cast Ni-base superalloy K417 was studied.All experiments were carried out under total strain control with temperature cycling between 400-850℃.Both in-phase and out-of-phase TMF specimens exhibited cyclic hardening followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the maximum temperature.OP TMF life was longer than of IP TMF.Various damage mechanisms operating in different controlled strain ranges and phasing were discussed.A few life prediction methods for isothermal fatigue were used to handle TMF fatigue and their applicability to superalloy K417 was evaluated.The SEM analysis of the fracture surface showed that transgranular fracture was the principal cracking mode for both IP and OP TMF.Oxidation was the main damage mechanism in causing shorter fatigue life for IP TMF compared with OP TMF. 相似文献
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