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Junqi Chen Weishuang Fang Yifan Zhai Feihu Li Ying Tang Jie Li Huanhuan Guo Liang Fang 《Journal of the European Ceramic Society》2021,41(8):4473-4477
Orthorhombic-structured CaIn2O4 ceramics with a space group Pca21 were synthesized via a solid-state reaction method. A high relative density (95.6 %) and excellent microwave dielectric properties (εr ~11.28, Qf = 74,200 GHz, τf ~ ?4.6 ppm/°C) were obtained when the ceramics were sintered at 1375 °C for 6 h. The dielectric properties were investigated on the basis of the Phillips–Van Vechten–Levine chemical bond theory. Results indicated that the dielectric properties were mainly determined by the InO bonds in the CaIn2O4 ceramics. These bonds contributed more (74.65 %) to the dielectric constant than the CaO bonds (25.35 %). Furthermore, the intrinsic dielectric properties of the CaIn2O4 ceramics were investigated via infrared reflectivity spectroscopy. The extrapolated microwave dielectric properties were εr ~10.12 and Qf = 112,200 GHz. Results indicated that ion polarization is the main contributor to the dielectric constant in microwave frequency ranges. 相似文献
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本文通过地浸采铀专家系统的研制,讨论了Dempster/Shafer证据理论方法的理论基础及特点,并结合铀矿床地浸采铀评价结果的生成,介绍了此方法的使用步聚。 相似文献
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本文总结了声发射现场监测预报的试验结果,提出了采场稳定性预测的综合方法,应用灰色理论预测和神经网络方法较好地解决了采场冒顶预报问题。 相似文献
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ABSTRACT Many planning agencies worldwide now see climate change response as unavoidable. This paper proposes that a central task for contemporary planning theory is to guide planning practice as it develops multi-dimensional responses. We examine three theoretical constructs: anticipatory governance, legitimacy and social-ecological resilience. We argue that each conceptualises challenges climate change presents to planning practice, while providing theoretically informed options for responses. Building on this, we utilize Friedmann’s [2008. “The Uses of Planning Theory: A Bibliographic Essay.” Journal of Planning Education and Research 28 (2): 247–257. doi:10.1177/0739456X08325220] tasks for planning theory as a framework to assess the utility of planning theories to guide climate change response through practice. Associated issues are discussed, including the influence of translatable planning theories and the value of importing knowledge from other disciplines. The paper concludes that more sophisticated interplay between planning theory and practice may improve planning responses to the climate change threat. The need for planning theory to translate its conceptual discoveries to the domain of practice is key. 相似文献
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本文根据对全国冶金系统的三次问卷调查所收集的大量原始数据,分析了安全系统工程的理论优势及主要安全分析与评价方法的应用状况,统计了这些方法在企业中适用的工作类型、作业类型、应用层次及相互关系,并对理论要求与实际应用水平作了比较分析。 相似文献
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To assess the dose of UV light needed to achieve specified levels of Giardia spp. cysts and Cryptosporidium spp. oocysts inactivation in drinking water, a Bayesian meta-analysis is used to analyze experimental data from several studies. Of the 20 studies identified by an extensive data collection effort, 14 (five reported experiments on Giardia and nine on Cryptosporidium) were selected for analysis based on a set of criteria. A substantial amount of the log inactivation data are reported as greater than a given inactivation level (i.e., censored data). The Bayesian hierarchical modeling approach used in this study not only properly addresses the common concerns in a meta-analysis but also provides a robust method for incorporating censored data. Different statistical models will result in different estimates of the UV doses needed to achieve a specific inactivation level. The Bayesian approach allows us to present the uncertainty in terms of risk, which is better suited for supporting US EPA in developing regulations. 相似文献