Search

Your search keyword '"Shi Wangzhou"' showing total 605 results
Start Over Author "Shi Wangzhou"
605 results on '"Shi Wangzhou"'

1. 3D Dirac semimetals supported tunable terahertz BIC metamaterials

Author

He Xiaoyong, Lin Fangting, Liu Feng, and Shi Wangzhou

Subjects
bic resonance, dirac semimetals, metamaterials, terahertz, Physics, QC1-999
Abstract

Based on the 3D Dirac semimetals (DSM) supported tilted double elliptical resonators, the tunable propagation properties of quasi-bound in continuum (BIC) resonance have been investigated in the THz regime, including the effects of rotation angles, DSM Fermi level, and the configuration of resonators. The results manifest that by altering the rotation angle of elliptical resonator, an obvious sharp BIC transmission dip is observed with the Q-factor of more than 60. The DSM Fermi level affects the BIC resonance significantly, a sharp resonant dip is observed if Fermi level is larger than 0.05 eV, resulting from the contributions of reflection and absorption. If Fermi level changes in the range of 0.01–0.15 eV, the amplitude and frequency modulation depths are 92.75 and 44.99%, respectively. Additionally, with the modified configurations of elliptical resonators, e.g. inserting a dielectric hole into the elliptical resonator, another transmission dip resonance is excited and indicates a red shift with the increase of the permittivity of the dielectric filling material. The results are very helpful to understand the mechanisms of DSM plasmonic structures and develop novel tunable THz devices, such as modulators, filters, and sensors in the future.

Published
2022
Full Text
View/download PDF

6. Synaptic transistor based on reversible hydrogenation of graphene channel.

Author

Hu, Yiqian, Huang, Lei, Chang, Quanhong, Peng, Xun, Hu, Gujin, and Shi, Wangzhou

Subjects
GRAPHENE, TRANSISTORS, HYDROGENATION, DEHYDROGENATION, ELECTROLYTES
Abstract

Graphene transistors with a gate-controlled transition of neuromorphic functions between artificial neurons and synapses have attracted increasing attention because the atomic thickness could be easily modulated by different stimuli, which is very beneficial for synaptic applications. As a modulation method, a graphene electrolyte-gated transistor (EGT) has been proposed, in which the electrical conductance of the graphene channel is modulated by reversible electrochemical hydrogenation of graphene. However, only a sparse physically realized graphene-based synaptic H+-EGTs have been reported due to the difficulty of achieving a high concentration of protons at the electrolyte–graphene interface. Here, we have reported the H+-EGTs with a highly defective graphene channel and a gel electrolyte [H3PO4/poly(vinyl alcohol)], which is based on hydrogenation and dehydrogenation of highly defected-graphene, performing the similar functions as the common artificial synaptic transistors, with good retention (<1% attenuation per minute), analog tunability (>200 nonvolatile states), and precisely controllable resistance (∼0.4% step flipped per synaptic event). In addition, the cyclic voltammetry test was applied to confirm the hydrogenation and dehydrogenation of the graphene channel. It is expected that this principle can provide ideas for designing graphene-based artificial synapses enabling integrated functions of in-memory computing and in-memory sensing for the neuromorphic system. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

10. A new LHe-free cryostat for the heterodyne SIS receiver for the Leighton Chajnantor Telescope.

Author

Li, Yao, Cao, Duo, Zhang, Yi, He, Xiaoyong, Liu, Feng, Shi, Wangzhou, and Shu, Chenggang

Subjects
SUBMILLIMETER astronomy, LIQUID helium, LABOR costs, THERMAL analysis, CRYOSTATS
Abstract

The Leighton Chajnantor Telescope (LCT) is an international collaborative program among Caltech, Shanghai Normal University (ShNU), and Universidad de Concepción (UdeC), aiming at the refurbishment and relocation of the Caltech Submillimeter Observatory (CSO) telescope from Mauna Kea, Hawaii, to the Chajnantor Plateau, northern Chile. A suite of excellent-sensitivity heterodyne superconductor–insulator–superconductor (SIS) receivers will be deployed to the telescope as the first set of instrumentations for high-resolution spectral observation. However, the current refrigeration technology for this receiver utilizes liquid helium (LHe), which greatly increases the cost of cooling and labor. To address this problem, a new LHe-free cryostat for the LCT heterodyne SIS receiver has been designed, fabricated, and tested. Mechanical and thermal analyses were performed to ensure that the cryostat meets the requirements of the telescope pointing accuracy and the SIS junction working environment, respectively. The experiment testing results are in good agreement with the calculation and analysis, indicating that the proposed LHe-free cryostat meets the operational requirements of the telescope at the new site. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

21. Pressure-induced structural transition of ZnO nanocrystals studied with molecular dynamics

Author

Dong, Xinwei, Liu, Feng, Xie, Yiqun, Shi, WangZhou, Ye, Xiang, and Jiang, J. Z.

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

We have studied the pressure-induced structural transition of ZnO nanocrystals using constant pressure molecular dynamics simulations for finite system. We have observed the transition from the fourfold coordination wurtzite to the sixfold coordination rocksalt structure, and the process of transition is strongly dependent on the morphology of the nanocrystals. It is found that the perfect faceted ZnO nanocrystals undergo wurtzite to rocksalt transition with a perfect fivefold h-MgO structure as the intermediate status. But for the faceted ones without perfect surface structure, as the number of the atoms removed from the (001) and (00-1) surface edge increases, the local morphology will become more similar to spherical. The nanocrystal will receive equal stress from every direction and it will be more difficult to compress the structure along only c axis as the perfect faceted ZnO nanocrystal. In this situation, only partial structure experiences intermediate fivefold coordination structure or even no intermediate fivefold coordination structure exists dependent on the surface disorder level.

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results