共查询到19条相似文献,搜索用时 46 毫秒
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应用模糊数学和系统工程的原理和方法,对除尘器的优化选型进行了分析和研究,提出了一种除尘器优化选型的模糊数学模型,并对该模型的有效性和精确性进行了实例验证。 相似文献
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M. E. Evans 《Die Naturwissenschaften》1983,70(10):485-494
Two distinct types of motion are commonly attributed to the geomagnetic poles — polar wander and dipole wobble. But two or three decades of intensive effort have failed to provide a sound understanding of either. Why? Polar wander is a very slow phenomenon associated with time scales of 107 to 108 years and thus intimately connected with the drift of the continents arising from plate tectonics. While there is no question of the validity of relative movements between the continents and the pole, the possibility of independent polar motion remains debatable. Dipole wobble is a more rapid phenomenon, most likely associated with time scales of 106 years or less. Currently the geomagnetic axis diverges from the Earth's spin axis by 11 1/2°, but paleomagnetic data indicate that, when averaged over a million years or so, the two coincide. Dipole wobble is the supposed mechanism responsible. The main difficulty here is one of isolating any dipole effects from perturbations of similar magnitude arising from the non-dipole fraction of the geomagnetic field — the so-called secular variation. Recent studies have significantly advanced our understanding of the secular variation, but the dipole wobble remains enigmatic. 相似文献
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郭召志 《防灾科技学院学报》2002,4(3):1-4
要想成为一个合格的教师,必须具备教育行业基本的职业道德;必须尊重学生,理解学生,关心学生,平等地对待每一个学生,建立和谐的师生关系;必须注重教师仪表,加强教师修养,在学生中树立起自己的形象。 相似文献
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