排序方式： 共有135条查询结果，搜索用时 0 毫秒
131.
无线电能传输是通过电磁波进行电力传输,从而省去电源线和插座的一种新型电源。本设计的无线电能传输系统采用电磁感应方式,充分结合了磁耦合技术和开关电源技术。系统分为无线发射部分和接收部分,在12V电源供电下,3mm距离耦合时效率达到了67%,输出功率1.16W。整个电路结构简单,工作稳定,经过检验在6cm范围内能够点亮发光二极管,达到了实际应用水平。 相似文献
132.
Chellachamy Manoharan Kasinathan Veeramuthu Ramdoss Venkatachalapathy Ramasamy Ilango 《浙江大学学报(A卷英文版)》2008,9(7):988-993
This study investigates the magnetic mineralogy and paleointensity values of a collection of archaeological artifacts （pottery）. The actual magnetic carriers and their domain states present in the archaeological pottery were obtained using the low field susceptibility, thermomagnetic curves and acquisition of isothermal remanence. The magnetic mineralogy of all the samples was dominated by ferrimagnetic mineral （magnetite/magnetite with low titanium content）, which was suitable for paleointensity measurements. The geomagnetic paleointensity value obtained by subjecting them to modified Thellier and Thellier method, is found to be （48.81±0.15） μT. 相似文献
133.
Zhang Xiaobing Hu Yin Chen Wen Huang Gang Nie Shengdong 《Journal of Zhejiang University. Science. B》2021,22(6):462-475
To overcome the computational burden of processing three-dimensional(3 D) medical scans and the lack of spatial information in two-dimensional(2 D) medical scans, a novel segmentation method was proposed that integrates the segmentation results of three densely connected 2 D convolutional neural networks(2 D-CNNs). In order to combine the lowlevel features and high-level features, we added densely connected blocks in the network structure design so that the low-level features will not be missed as the network layer increases during the learning process. Further, in order to resolve the problems of the blurred boundary of the glioma edema area, we superimposed and fused the T2-weighted fluid-attenuated inversion recovery(FLAIR) modal image and the T2-weighted(T2) modal image to enhance the edema section. For the loss function of network training, we improved the cross-entropy loss function to effectively avoid network over-fitting. On the Multimodal Brain Tumor Image Segmentation Challenge(BraTS) datasets, our method achieves dice similarity coefficient values of 0.84,0.82, and 0.83 on the BraTS2018 training; 0.82, 0.85, and 0.83 on the BraTS2018 validation; and 0.81, 0.78, and 0.83 on the BraTS2013 testing in terms of whole tumors, tumor cores, and enhancing cores, respectively. Experimental results showed that the proposed method achieved promising accuracy and fast processing, demonstrating good potential for clinical medicine. 相似文献
134.
目的:提高对脑缺血后出现短T1高信号的认识并探讨其临床意义。方法:分析23例患者脑梗塞后出现短T1高信号的MRI表现,全部病例均同时行CT检查和随访。结果:病变位于基底节区15例,皮、髓质区5例,小脑3例;基底节区病变呈斑片状短T1信号,皮、髓质区及小脑病变呈散在斑点状短T1信号改变;23例MRI检查出现短T1信号后,立即行CT检查,22例病变中无高密度影,1例枕叶梗塞部位出现少许点状高密度影与MR图像相似。结论:脑缺血后出现短T1高信号并非出血,而是多种因素综合所致,这对临床正确治疗选择很有意义。 相似文献
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