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介绍一种测定不能用机械方法加工到所需精确尺寸的“固体材料”（农产品或矿物）介电特性的新方法．将这类已知“固体密度”的材料研碎,成为“空气粒子”混合物,在几个不同的“松密度”上测量其介电特性．利用“空气粒子”混合物的“松密度”和它的介电常数及损耗因子的线性函数关系,外推到“固体密度”,从而获得“固体材料”的介电特性． 相似文献
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<正>PROBLEM In recent years,the rapid development of artificial intelligence (AI) technology,especially machine learning and deep learning, is profoundly changing human production and lifestyle.In various fields,such as robotics,face recognition,autonomous driving and healthcare,AI is playing an important role.However,although AI is promoting the technological revolution and industrial progress,its security risks are often overlooked.Previous studies have found that the wellperforming deep ... 相似文献
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By Su Lijie 《中外文化交流(英文版)》2006,(2):10-11
Old place names are witnesses of a city＇s history. In modern times,should these names be changed to come up With presenT-aay realities？ It is a topic that today＇s city dwellers are concerned about. 相似文献
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Su GAO 《Frontiers of Education in China》2014,9(4):519-551
The assumption that inquiry-based instruction is more effective in influencing student science achievement than traditional didactic teaching has been the driving force of science education reform in recent decades and in many countries. However, the empirical relationship between these two kinds of science teaching and student science performance is not soundly established, which is worth a careful examination. Framed through the theoretical perspectives of inquiry-based instruction and culturally relevant pedagogy, using a two-level hierarchical linear modeling (HLM) approach and simultaneous multiple regression, this study examines the above relationship using the Trends in International Mathematics and Science Study (TIMSS) 2011 8th grade dataset from Singapore, Chinese Taipei, and the US. The study found that for the low-performing students, none of the inquiry-based teaching practice items measured had a significant relationship with the science achievements at any performance levels of students in any country/region except for the case of two inquiry-based teaching practice items that were positively related to Chinese Taipei students’ achievements. No didactic teaching practice items were associated with the Singapore students’ science achievement, three of these practice items were found negatively related to Chinese Taipei students’ science achievement, and one traditional didactic teaching practice was negatively related to the science achievement of U.S. students. However, for medium- and high-performing students, none of these inquiry-based or traditional didactic science-teaching practices were found to be positive predictors of science performance in all three countries/regions. However, in the case of Chinese Taipei, one didactic teaching practice item was negatively related with the medium level performing students’ achievement and two didactic teaching practices were found to hinder high-performing students’ science achievements. 相似文献
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使用HP8510自动网络分析仪测量固体材料的相对介电常数和导磁率 总被引：1，自引：0，他引：1
介绍了使用ＨＰ８５１０自动网络分析仪系统测量固体材料的εｒ和μｒ的基本理论及其步骤，其特点是测量速度快，在一定条件下精度高，可在所要测量的频人的高至４０１个频为上同时读取εｒ和μｒ值，且其测试用工夹具（试样容器）易于加工制造，还给出对三咱材料（聚四氟乙烯、尼龙和多晶形铁）分别在同轴型和波导型试样容器中的测量结果。 相似文献
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Objective
This study aimed to investigate child physical abuse (CPA) while taking into account the more rigorous definitions of CPA in the Chinese societies. The prevalence of CPA and CPA-related PTSD were estimated, together with the examination of peri-traumatic subjective reactions and their impacts on PTSD.Methods
In a Taiwanese sample of 1966 4th to 8th graders, the Chinese version of UCLA PTSD Reaction Index for DSM-IV (Steinberg, Brymer, Decker, & Pynoos, 2004) was used to investigate the lifetime exposure to CPA. A sub-sample of 236 traumatized CPA victims was examined with respect to related PTSD symptoms.Results
Thirty-four percent of the children had been exposed to CPA. The estimated current prevalence of full and partial PTSD was 13.6% and 16.9%, respectively.Conclusions
The current CPA prevalence was found to be higher than the Western countries, but lower than the previous findings in other East Asian societies. The full PTSD prevalence was close to the findings in the Western countries, whereas sub-clinical PTSD was less observed in Taiwan. Peri-traumatic subjective reactions, that is, Criterion A2 and perceived threat, were shown to be major predictors of PTSD symptom severity. The role of attitudes of child discipline in the Chinese societies in the prevalence of CPA and CPA-related PTSD is discussed.Practice implications
By providing explicit epidemiological information of CPA and CPA-related PTSD in Taiwan, the current study extends our understanding of CPA and CPA-related PTSD more broadly from Western countries to the Eastern societies. By separately investigating CPA relating to different perpetrators, cross-study comparison is enhanced. In the current study, the significance of considering cultural background in defining CPA and examining CPA-related PTSD was pointed out. Meanwhile, the role of victims’ subjective reactions in the psychopathology of PTSD is highlighted. The findings and discussions could contribute for generating a more sophisticated clinical practice, especially with Asian or Chinese cases. 相似文献30.
One challenge of generating a liquid aerosol is finding an efficient way to break up bulk amounts of the compound into micron-sized droplets. Traditional methods of aerosol generation focus on the principle of creating the liquid droplets by blowing air at high speed over or through a liquid. In this study, a novel micropump droplet generator (MDG) is proposed based on a microfluidics device to produce monodisperse droplets on demand (DoD). The micropump design was employed to both pump the fluid into the air and to encourage droplet breakup and aerosol formation. Computational simulation modeling of the new MDG was developed and validated with comparisons to experimental data for current generators. The device was found to produce an aerosol similar to a vibrating orifice DoD device. Most importantly, the input power required by the newly proposed device (MDG) was several orders of magnitude below existing DoD generators for a similar droplet output. Based on the simulation results obtained in comparison with current DoD generators, the MDG device performed effectively at higher frequencies, smaller nozzle diameters, and regardless of the liquid viscosity of the solution. 相似文献