Search

Your search keyword '"Song, Zicheng"' showing total 37 results
Start Over Author "Song, Zicheng"
37 results on '"Song, Zicheng"'

1. Smith-Purcell radiation from time grating

Author

Zhu, Juan-Feng, Nussupbekov, Ayan, Zhou, Wenjie, Song, Zicheng, Wang, Xuchen, Zhang, Zi-Wen, Du, Chao-Hai, Bai, Ping, Png, Ching Eng, Qiu, Cheng-Wei, and Wu, Lin

Subjects
Physics - Optics, Physics - Applied Physics, Physics - Plasma Physics
Abstract

Smith-Purcell radiation (SPR) occurs when an electron skims above a spatial grating, but the fixed momentum compensation from the static grating imposes limitations on the emission wavelength. It has been discovered that a temporally periodic system can provide energy compensation to generate light emissions in free space. Here, we introduce temporal SPR (t-SPR) emerging from a time grating and propose a generalized t-SPR dispersion equation to predict the relationship between radiation frequency, direction, electron velocity, modulation period, and harmonic orders. Compared to conventional SPR, t-SPR can: 1) Provide a versatile platform for manipulating SPR emission through temporal modulation (e.g., period, amplitude, wave shape). 2) Exhibit strong robustness to the electron-grating separation, alleviating the constraints associated with extreme electron near-field excitation. 3) Introduce additional energy channels through temporal modulation, enhancing and amplifying emission., Comment: 6 pages, 3 figures

Published
2023

14. Inverse Design of Diffusion–Absorption Hybrid Metasurfaces.

Author

Song, Zicheng, Zhang, Ruicong, Min, Pingping, Wang, Tianyu, Cao, Wenxin, He, Yurong, Wu, Lin, Zhu, Jiaqi, and Qiu, Cheng‐Wei

Subjects
*IMPEDANCE matching, *RADAR cross sections, *DIFFUSION, *SURFACE diffusion
Abstract

Random metasurfaces have demonstrated significant potential in radar‐signature control applications, but their ability to manipulate scattering‐field reduction is limited by relying solely on the diffusion mechanism. To achieve flexible and arbitrary designs for scattering‐field reduction, a diffusion–absorption hybrid metasurface is proposed based on the Babinet principle. This hybrid metasurface adopts complementary bilayer metasurfaces to satisfy the impedance matching condition and employs a hybrid absorption and diffusion mechanism. Such complementary designs' intralayer resonances and interlayer couplings are tailored by multi‐objective optimization, achieving the precise and wideband design of absorptive elements with a specific reflection phase. By optimizing the spatial distributions of elements, diffusion is introduced and designs are achieved with a continuous scattering‐field reduction from 15.40 to 32.58 dB at 15 GHz. Three representative designed structures are fabricated and verified as proof of concept. The experimental results are consistent with the calculations and simulations, demonstrating a 12.32–24.46 dB scattering‐field reduction range. The proposed high‐freedom metasurface and the implementation multi‐objective optimization strategy collectively empower flexible wavefront manipulation, offering a viable solution for designing hybrid meta‐devices that incorporate multiple mechanisms. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

31. Giant magneto-impedance effect in [Ni.sub.80][Fe.sub.20] composite multilayers

Author

Song, Zicheng, Yuan, Wangzhi, Zhao, Zhenjie, Ruan, Jianzhong, Yang, Xielong, Sect, H.L., and Li, X.P.

Subjects
Electromagnetism -- Research, X-rays -- Diffraction, X-rays -- Research, Business, Electronics, Electronics and electrical industries
Abstract

The giant magneto-impedance (GMI) effect of [(NiFe/Si[O.sub.2]).sub.n]/Cu/[(Si[O.sub.2]/NiFe).sub.n] composite multilayers is investigated. The results show that the magnitude of the GMI effect changes with an increasing number of layers n of bilayers Si[O.sub.2]/NiFe. At n = 3, the maximum MI ratios reached 17.08%. When n was further increased to four and five, the MI ratios decreased slightly. This is mainly attributed to changes in the samples' magnetic characteristics, which is due to the influence of the magnetic moment direction of the NiFe layer and the inner stress. Index Terms--Giant magneto-impedance (GMI), magnetic hysteresis loop, [Ni.sub.80] [Fe.sub.20] composite multilayers, X-ray diffraction (XRD).

Published
2006

32. MicroRNA profile comparison of the corneal endothelia of young and old mice: implications for senescence of the corneal endothelium

Author

Zhao, Xiaowen, Huang, Yusen, Wang, Ye, Chen, Peng, Yu, Yang, and Song, Zicheng

Subjects
Aging, Mice, Inbred BALB C, Gene Expression Profiling, Endothelium, Corneal, Computational Biology, Gene Expression Regulation, Developmental, Reproducibility of Results, Molecular Sequence Annotation, Mice, MicroRNAs, Animals, Gene Regulatory Networks, Cellular Senescence, Research Article, Oligonucleotide Array Sequence Analysis
Abstract

Purpose To identify critical microRNAs (miRNAs) that play important roles in regulating the aging of corneal endothelial cells in mice aged 10–13 weeks and 2 years. Methods We collected the corneal endothelia from 30 mice aged 10–13 weeks and 30 mice aged 2 years. The samples were pooled into six groups (Y1, Y2, Y3 and S1, S2, S3). Each group comprised corneal endothelia from 10 mice, and these six groups were used for a genome-wide miRNA microarray study. The expression levels of eight selected miRNAs were further validated independently by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Target genes were predicted using a computational approach due to their base-pairing rules between miRNA and messenger RNA target sites. The locations of binding sequences were within the target’s 3′ untranslated regions (UTR), and the conservation of target binding sequences occurred within related genomes. Additional gene ontology and signaling pathway analyses were performed using bioinformatics tools. Results Twenty-seven miRNAs (7 upregulated and 20 downregulated) were found to be differentially expressed (fold change >2, p value

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results