排序方式: 共有8条查询结果,搜索用时 796 毫秒
1
1.
基于运动想象的脑机接口可以控制外部设备,在医疗康复领域中有着重要的临床意义。为了提高运动想象脑电信号的分类准确率,提出一种松散型小波神经网络,即双树复小波变换与神经网络分开进行计算再组合。利用DTCWT对预处理后的脑电信号进行分解,计算复小波系数的多个特征值并构建特征向量,将组合后的特征向量送入神经网络中进行分类识别。实验结果表明,该算法在BCI Competition IV的数据集2a上的平均准确率为76.03%。通过与不同分类器和现有方法的比较,验证了松散型小波神经网络的有效性。 相似文献
2.
In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy (SNOM). Optical writing and subsequently topographic reading of the patterns with subwavelength resolution were carried out in our experiments. Nanometer scale dots and lines were successfully fabricated on the films and the smallest dot diameter is about 120 nm. The width of the line fabricated is about 250 nm. This method is also a choice for nanolithography. The mechanism of the surface deformation on the polymer films was briefly analyzed from the viewpoint of gradient force in the optical near field. The intensity distribution of the electric field near the tip aperture was numerically simulated using finite-difference time-domain (FDTD) method and the numerical simulation results were consistent with the experimental results. 相似文献
3.
4.
5.
In this article, mono-dispersed hexagonal structure CdSe nanocrystals with polyhedron shape were prepared by an open solvent thermal reaction. They show a discrete excitonic transition structure in the absorption spectra and the minimal photoluminescence (PL) peak full-width at half-maximum of 19nm. The PL quantum yield is about 60%. Transmission electron micrographs, high-resolution transmission electron micrographs, x-ray powder diffraction patterns, UV-vis absorption spectra and PL spectra were obtained for the as-prepared CdSe nanocrystals. The size of the CdSe nanocrystals can be tuned by changing the reaction temperature or time. Due to the improved synthesis method, a different growth mechanism of the CdSe nanocrystals is discussed. 相似文献
6.
7.
8.
Photoluminescence and electroluminescence properties of ZnO films on p-type silicon wafers
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A simplified n-ZnO/p-Si heterojunction has been prepared by growing
n-type ZnO rods on p-type silicon wafer through the chemical vapour
deposition method. The reflectance spectrum of the sample shows an
independent absorption peak at 384 nm, which may be originated from
the bound states at the junction. In the photoluminescence spectrum a
new emission band is shown at 393 nm, besides the bandedge emission
at 380 nm. The electroluminescence spectrum of the n-ZnO/p-Si
heterojunction shows a stable yellow luminescence band centred at 560
nm,which can be attributed to the emission from trapped states.
Another kind of discrete ZnO rod has also been prepared on such
silicon wafer and is encapsulated with carbonated polystyrene for
electroluminescence detection. This composite structure shows a weak
ultraviolet electroluminescence band at 395 nm and a yellow
electroluminescence band. These data prove that surface modification
which blocks the transverse movement of carriers between neighbouring
nanorods plays important roles in the ultraviolet emission of ZnO
nanorods. These findings are vital for future display device design. 相似文献
1