A polycrystalline La2/3 (Ca0.60 Ba0.40 ) 1/3 MnO3 was prepared by standard solid reaction method. Magnetization(M) and magnetoresistance of the sample were meas
为了解决网络电话(VoIP)业务面临的Internet垃圾电话(SPIT)问题,在针对SPIT检测方案的基础上提出利用人类会话模型对会话进行建模,在该模型的基础上将会话转化为表征会话模式
现有的SVM主动反馈算法普遍受到小样本问题和不对称分布问题的制约.针对这些问题,文中提出一种基于偏袒性半监督集成的SVM主动反馈技术.该算法在集成学习框架中使用未标记数据以增加个体分类器之间的差异性,从而获得高效的集成分类模型.同时,高效的集成分类模型更有利于寻找富有信息样本,进而也提高主动反馈的效率.此外,文中还设计一种偏袒加权策略,使得集成分类模型对正样本给予更大的关注程度,以应对正负样本间的
将亮氨酸作为C末端氨基酸,采用片段缩合策略(2+7)合成亮丙瑞林.液相法合成困难序列Fmoc-Arg(Pbf)-Pro-NHEt时,以DIC为缩合试剂,THF作为溶剂,Pro-NHEt·HCl与Fmoc-Arg(Pbf)-OH
Much of the recent progress in understanding angiosperm phylogeny has been achieved using multi-gene or plastid genome datasets. However, it is largely unclear
Caytoniales are an important group of seed plants, and the nature of their female reproductive organ may influence interpretations of the seed plant phylogeny a
Worldwide construction and demolition waste (CDW) is currently dumped. To close the building cycle and the building materials cycle by recycling CDW in high tec
分数阶微分理论用于图像处理是近期一个新的研究课题.文中从分数阶微分对图像细微细节的增强能力出发,对分数阶微分的机理进行分析,且根据分数阶微分Tiansi算子的作用特点,提出一种可大幅增强边缘信息值的改进Tiansi算子方法.具体的做法是将Tiansi模板分解为8个不同方向的小模板,得到像素点周围8个方向的加权求和值.然后将8个值进行不同的分组,得到增强幅度不同的3种改进方法.最后通过增强的实验表明
Salvia L. (family Lamiaceae), a large genus of over 1000 species, is widely distributed throughout tropical and temperate regions of the world. Eight-four speci