Results 71 to 80 of about 42,313 (202)
Ba6Ti2Nb8O30和Sr6Ti2Nb8O30陶瓷的驰豫铁电性能
四川大学学报. 自然科学版, 2005 作者用固相烧结方法合成了具有充满型钨青铜结构的Ba6Ti2Nb8O30和Sr6Ti2Nb8O30陶瓷.不同频率下Ba6Ti2Nb8O30和Sr6Ti2Nb8O30陶瓷介电常数随温度的变化的规律表明,这两种陶瓷的铁电-顺电相变具有明显的驰豫铁电相变特征,相变弥散指数分别为1.95与1.41.它们在1MHz时的居里温度分别为155℃和160℃,两者的居里温度十分相近.同时,对其介电性能的电场可调性进行了初步研究.当外加电场为2kV/cm、频率为10kHz时 ...
袁媛, 陈湘明
doaj
The Effects of Gen‐AI on Situated and Future‐Driven Academic Writing Motivation
International Journal of Applied Linguistics, EarlyView.ABSTRACT Despite the increasing use of Generative Artificial Intelligence (Gen‐AI) in education, there is still a significant gap in understanding its effects on the situated‐ and future‐driven motivation in academic writing. This longitudinal design‐based research sought to explore variations in academic writing motivation of 110 Chinese university ...
Xiao Hu +3 more
wiley +1 more source
四川大学学报. 自然科学版, 2011 本文主要是研究金属铁经历冲击—卸载到熔化压力区,其内部发生熔化相变时,铁/蓝宝石界面的辐亮度和温度随时间演化特性,发现辐亮度随时间持续增强而界面却经历了一个慢降温过程,该特征与无相变或瞬时相变的热传导模型结论不一致,即无熔化相变或瞬时相变时,界面温度是一个稳定值.本文结合熔化相变动力学模型与热传导方程对实验现象给出一种理论解释.模型计算所给出的温度历史与观测结果一致,由此可以校对其它测量或者计算熔化温度的方法和模型计算的结果,并能够初步限定出该压力下铁的熔化成核速率和径向长大速率.
张世来 +5 more
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International Journal of Applied Linguistics, EarlyView.ABSTRACT This qualitative multiple case study explores multilingual postgraduate students’ academic identities through writing at an EMI university in Hong Kong, with a focus on how they gain legitimacy in knowledge‑making with their multilingual repertoires. Grounded in a poststructuralist understanding of identities as fluid and negotiated, the study
Siqi Song, Ken Lau
wiley +1 more source
Gaoya dianqi, 2010 断路器在随机关合空载变压器时会产生幅值、频率很高的励磁涌流,这种操作暂态可能导致微机继保装置误动作,降低用户电能质量和系统可靠性。根据空载变压器涌流产生的机理,采用选相关合技术消除变压器励磁涌流,研究了铁心剩磁和最佳关合相位关系;分析了断路器截流和暂态恢复电压对铁心剩磁影响,并给出了剩磁测量方法。在空载变压器选相关合原理基础上,采用ATP-EMTP软件建立空载变压器关合模型,对暂态过程进行了仿真。仿真结果表明,选相关合技术能有效消除空载变压器合闸时产生的励磁涌流,为空载变压器选相关合提供了理论基础。
李伟 +4 more
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Designing Integrated Policies for the Twin Transition: Challenges and Tradeoffs
Policy Studies Journal, EarlyView.ABSTRACT Democratic governance faces the intertwined imperatives of managing the transformative risks and opportunities of digitalization, particularly stemming from artificial intelligence (AI), while achieving environmental sustainability within planetary boundaries.
Martino Maggetti
wiley +1 more source
Coalition Breakdown and Subsystem Exit
Policy Studies Journal, EarlyView.ABSTRACT Why actors choose to work together (or not) to advance policy has been the central area of inquiry within the Advocacy Coalition Framework (ACF). Existing research has mainly emphasized the pathway towards coalition formation and evolution, underscoring the stable patterns of allies and opponents observable in policy processes over a decade or
Charlie F. Thompson
wiley +1 more source
World Food Policy, Volume 12, Issue 2, November 2026.ABSTRACT Household food expenditure continues to be a key factor in ensuring the realization of the Human Right to Adequate Food. Particularly in Brazil, access to food can be limited by economic constraints in vulnerable families, especially among farming families, who have been more vulnerable to food insecurity in recent years in the country.
Lucas de Almeida Moura +3 more
wiley +1 more source