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陈华 《湖南理工学院学报:自然科学版》1996,(1)
本文研究了淬火工艺对低和中碳铬钢的显微组织,冲击韧性和断裂机制的影响,得出了无论是低碳,还是中、高碳钢,当奥氏体长大倾向稍大时,采取提高加热温度进行淬火的工艺均为不可取的结论。 相似文献
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汞原子处于激发态时,有4种能级状态,只有63P1第一激发态容易观测,而较高激发态则不易观测本文介绍汞原子较高激发态的观测的实验方法.现象明显,效果很好. 相似文献
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为利用中分辨率成像光谱仪(MODIS)多通道云图数据对云相态进行分类,提出了一种利用云图红外、可见光谱段数据,基于SABP神经网络的云相态分类算法.算法基于BP人工神经网络学习算法及模拟退火算法.在两算法结合的基础上,作出了有益于云相态分类的改进.基准网络模型为3层前馈BP网络,其中,隐层和输出层使用不同的激活函数.选取了5种光谱特征作为网络输入,输出两单元判定结果.为加速收敛速度,避免振荡,采用了一种自适应的变学习系数、惯性系数策略.个例分析表明,算法在中低纬度地区效果良好. 相似文献
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郭令芬 《哈尔滨师范大学自然科学学报》2011,27(6):85-88
花敖包特银铅锌矿床位于内蒙古西乌珠穆沁旗宝日格斯台苏木境内,是一个近年来发现的与岩浆岩活动有关的热液脉状银铅锌多金属矿床.该文从花敖包特银铅锌多金属矿床地球化学数据出发,对矿区的地球化学体特征进行了分析研究.相对于中国东部陆壳丰度而言,本区容矿岩石强烈富集Ag、As、Pb、Sb、Zn(K1≥5);富集Bi、Cd、Hg、... 相似文献
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《Journal of Natural History》2012,46(17):2225-2249
Dung beetle guilds of different competitive level coexist at high abundances in the forest–savanna mosaic of Ivory Coast. A total of 25?875 specimens was recorded from 90 samples of fresh buffalo dung exposed for 4-h periods over the day in the Parc National de la Comoé. Redundancy analyses show different patterns of the guild structure determined by time of day, and positive correlations of guild abundance with temperature. The competitively superior telecoprids (rollers) have their abundance peak at midday when the high temperatures presumably enable them to perform their energetically costly rolling behaviour at greater speed. The competitively intermediate paracoprids (tunnellers) and the competitively inferior endocoprids (dwellers) have their peak around dusk when: (1) the superior competitors are not active, and (2) they can easily synchronize their flight activity using light intensity changes. During the two peaks of flight activity of the dung beetles, their abundance at the resource is very high, causing obvious competition. On the other hand, the resource is hardly used between 22:00?h and 10:00?h. This is probably due to physiological constraints (high optimum temperature required for the diurnal species and dependence on light intensity patterns as a flight trigger of the nocturnal species, respectively). Shifting flight activity to these periods of low competition does not occur, resulting in a unequal level of competition over the day, thus periods of considerable competition within dung beetle assemblages alternate with vacant temporal refuges. 相似文献
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在多元文化背景下,加强高校学生思想道德教育的重要性愈发凸显,而如何提高青少年思想教育的创新性和实效性则是此项工作的核心问题.加强徐特立纪念馆的建设及宣传工作,是开展高校学生思政教育的特色形式和有效途径,更是深化徐特立研究的有效推动力. 相似文献
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网络时代培养大学生信息素养对大学生的未来发展有重要意义,但当前高校在对大学生进行信息索养培养过程中面临着许多问题。针对这些问题本文提出了一些解决途径。 相似文献