排序方式: 共有54条查询结果,搜索用时 366 毫秒
1.
2.
王梦 《浙江大学学报(理学版)》2003,30(4):361-364
用旋转法结合Fourier估计以及Littlewood-Paley理论给出了乘积空间上带粗糙核的极大奇异积分算子的Lp有界性.证明了对于Ω∈Lq(Sn-1×Sm1),其中q>1,∫ sn-1Ω(x',y')dx'=0, y'∈Sm-1,∫ sm-1Ω(x',y')dy'=0, x'∈Sn-1,且b,h∈L∞(R1+),则积域上极大奇异积分算子T*(f)=supε1>0,ε2>0∫∫|u|>ε1|v|>ε2b(|u|)h (|v|)Ω(u',v')/|v|n|v|mf(x-u,y-v)dudv为Lp(Rn×Rm)有界,其中1<p<∞.从而改进了以往的结果. 相似文献
3.
本文考虑向列相液晶的动力学方程的Cauchy问题,并给出温和解在C([0, T); L~n)中解的唯一性. 相似文献
4.
5.
证明了当N的万有覆盖上存在一个多项式增长的非负严格凸函数时,不存在从R~3到N的非平凡拟调和球.于是在dim M=3时推广了Eells-Sampson的定理. 相似文献
6.
7.
针对传统卷积神经网络(CNN)同层神经元之间信息不能互传,无法充分利用同一层次上的特征信息,以及无法提取长距离上下文相关特征的问题.该文针对中文文本,提出字符级联合网络特征融合的模型进行情感分析,在字符级的基础上采用BiGRU和CNN-BiGRU并行的联合网络提取特征,利用CNN的强学习能力提取深层次特征,再利用双向门限循环神经网络(BiGRU)进行深度学习,加强模型对特征的学习能力.另一方面,利用BiGRU提取上下文相关的特征,丰富特征信息.最后在单方面上引入注意力机制进行特征权重分配,降低噪声干扰.在数据集上进行多组对比实验,该方法取得92.36%的F1值,结果表明本文提出的模型能有效的提高文本分类的准确率. 相似文献
8.
王梦 《浙江大学学报(理学版)》1999,26(4):1-7
本文讨论了乘积域Rn×Rm上一类带粗糙核的奇异积分算子的Lp(Rn×Rm)有界性。这里,Ω为原子Hardy空间H1a(Sn-1×Sm-1)中的函数,h为L∞(Lq)(R+×R+)中的径向函数,Φ(t)满足一定的增长条件。 相似文献
9.
Charge compensation and capacity fading in LiCoO_2 at high voltage investigated by soft x-ray absorption spectroscopy
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In order to obtain an in-depth insight into the mechanism of charge compensation and capacity fading in LiCoO_2, the evolution of electronic structure of LiCoO_2 at different cutoff voltages and after different cycles are studied by soft x-ray absorption spectroscopy in total electron(TEY) and fluorescence(TFY) detection modes, which provide surface and bulk information, respectively. The spectra of Co L2,3-edge indicate that Co contributes to charge compensation below 4.4 V.Combining with the spectra of O K-edge, it manifests that only O contributes to electron compensation above 4.4 V with the formation of local O 2 p holes both on the surface and in the bulk, where the surficial O evolves more remarkably. The evolution of the O 2 p holes gives an explanation to the origin of O_2~-or even O_2. A comparison between the TEY and TFY of O K-edge spectra of LiCoO_2 cycled in a range from 3 V to 4.6 V indicates both the structural change in the bulk and aggregation of lithium salts on the electrode surface are responsible for the capacity fading. However, the latter is found to play a more important role after many cycles. 相似文献
10.
证明了Hausdorff算子HΦ及HΦ,A在Triebel-Lizorkin型空间Fα,τp,q,上的有界性,并且求得HΦ相应的算子范数. 相似文献