Search

Your search keyword '"Zhang, Xiaoru"' showing total 551 results
Start Over Author "Zhang, Xiaoru" Publication Year Range Last 50 years
551 results on '"Zhang, Xiaoru"'

1. Klein Tunneling of Gigahertz Elastic Waves in Nanoelectromechanical Metamaterials

Author

Lee, Daehun, Jiang, Yue, Zhang, Xiaoru, Jahanbani, Shahin, Wen, Chengyu, Zhang, Qicheng, Johnson, A. T. Charlie, and Lai, Keji

Subjects
Physics - Applied Physics
Abstract

Klein tunneling, the perfect transmission of a normally incident relativistic particle through an energy barrier, has been tested in various electronic, photonic, and phononic systems. Its potential in guiding and filtering classical waves in the Ultra High Frequency regime, on the other hand, has not been explored. Here, we report the realization of acoustic Klein tunneling in a nanoelectromechanical metamaterial system operating at gigahertz frequencies. The piezoelectric potential profiles are obtained by transmission-mode microwave impedance microscopy, from which reciprocal-space maps can be extracted. The transmission rate of normally incident elastic waves is near unity in the Klein tunneling regime and drops significantly outside this frequency range, consistent with microwave network analysis. Strong angular dependent transmission is also observed by controlling the launching angle of the emitter interdigital transducer. This work broadens the horizon in exploiting high-energy-physics phenomena for practical circuit applications in both classical and quantum regimes., Comment: 15 pages, 5 figures, 14 pages of SI

Published
2024
Full Text
View/download PDF

6. The Relationship Between Soil Crust and Infiltration Under Simulation Continuous and Intermittent Precipitation

Author

LIU Zhiqiang, ZHANG Xiaoru, JIAO Fanxu, and LI Guanglu

Subjects
crust strength, bonding force, infiltration performance, infiltration reduction effect, continuous and intermittent precipitation, Environmental sciences, GE1-350, Agriculture
Abstract

[Objective] This study was aimed at investigating the variation relationship between soil crust and infiltration performance under continuous and intermittent rainfall conditions. [Methods] Three typical cultivated layer loesses were selected, and indoor simulated rainfall experiments were conducted to analyze the relationship between soil crust strength, cohesion, and infiltration performance under different rainfall conditions. [Results] (1) The infiltration performance decreased with the increase of continuous rainfall duration and intermittent rainfall events; under the same rainfall duration and intensity, the desilting effect of intermittent rainfall was higher than that of continuous rainfall. (2) Soil crust strength and cohesion increased with the increase of continuous rainfall duration and intermittent rainfall events; the infiltration performance of cinnamon soil and black earth was significantly linearly correlated with crust strength and cohesion (p < 0.05). The longer the continuous rainfall duration and the more frequent the intermittent rainfall events, the greater the soil crust strength, cohesion, and desilting effect. The infiltration performance of sandy soil was significantly nonlinearly correlated with crust strength and cohesion (p < 0.05). (3) The smaller the MWD and GMD of the crust, the worse the infiltration performance and the greater the desilting effect; furthermore, the correlation analysis results showed that the impact of intermittent rainfall on infiltration performance is higher. [Conclusion] Finally, under the same rainfall intensity, intermittent rainfall can form a more solid crust, which has a stronger weakening effect on soil infiltration performance. This study can provide a reference for the prevention and control of soil and water loss on the Loess Plateau and the effective utilization of water resources

Published
2024
Full Text
View/download PDF

10. Research on the Effect of Awards and Grants to Improve the Ability of Scientific Research after 2014 in China

Author

Yuan, Qunhua and Zhang, Xiaoru

Abstract

The National Graduate Education Comprehensive Fees Policy has been in operation for more than five years since the fall semester of 2014, which is long enough to evaluate the effectiveness of the policy. Base on the existing research results, this paper proposes to adopt the core index of graduate students' scientific research ability--the level and quantity of published papers to evaluate the implementation effect of this policy, take GF University as an example to analyze the construction of the university's award and scholarship system, and make quantitative analysis of the academic graduate students' published papers. It finds that the implementation effect of scholarship system is not obvious. Therefore, this paper analyzes the reasons and puts forward the relevant countermeasures.

Published
2020

11. Detection and demultiplexing of cylindrical vector beams enabled by rotational Doppler effect

Author

Zhang, Xiaoru, Jia, Junliang, Zhai, Kaiyi, Chang, Zehong, Guo, Zhenyu, and Zhang, Pei

Subjects
Physics - Optics
Abstract

Cylindrical vector beams (CVBs) detection is of vital significance in kinds of studies such as particle observation, mode-division multiplexing. Here we realize a comprehensive detection of cylindrical vector beams based on the rotational Doppler effect including analysis of topological charges, amplitudes, and phases for mode bases. We construct a mode demultiplexing scheme to obtain the amplitudes, phases in beating signal of collected scattering light by Fourier transformation. The method resolves both absolute values and signs of topological charges ofCVB simultaneously, which can not be simply realized by existing polarization examination techniques. It may be of big potential for related researches since an efficient, quantitative and complete scheme to detect CVBs is verified starting from this work., Comment: Manuscript under peer review by Laser & Photonics Reviews

Published
2021

37. A Double Auction Mechanism for Mobile Crowd Sensing with Data Reuse

Author

Zhang, Xiaoru, Gao, Lin, Cao, Bin, Li, Zhang, and Wang, Mengjing

Subjects
Computer Science - Computer Science and Game Theory
Abstract

Mobile Crowd Sensing (MCS) is a new paradigm of sensing, which can achieve a flexible and scalable sensing coverage with a low deployment cost, by employing mobile users/devices to perform sensing tasks. In this work, we propose a novel MCS framework with data reuse, where multiple tasks with common data requirement can share (reuse) the common data with each other through an MCS platform. We study the optimal assignment of mobile users and tasks (with data reuse) systematically, under both information symmetry and asymmetry, depending on whether the user cost and the task valuation are public information. In the former case, we formulate the assignment problem as a generalized Knapsack problem and solve the problem by using classic algorithms. In the latter case, we propose a truthful and optimal double auction mechanism, built upon the above Knapsack assignment problem, to elicit the private information of both users and tasks and meanwhile achieve the same optimal assignment as under information symmetry. Simulation results show by allowing data reuse among tasks, the social welfare can be increased up to 100~380%, comparing with those without data reuse. We further show that the proposed double auction is not budget balance for the auctioneer, mainly due to the data reuse among tasks. To this end, we further introduce a reserve price into the double auction (for each data item) to achieve a desired tradeoff between the budget balance and the social efficiency., Comment: This manuscript serves as the online technical report for the paper published in IEEE GLOBECOM 2017

Published
2017

42. Does digital financial inclusion reduce the risk of returning to poverty? Evidence from China.

Author

Xu, Fang, Zhang, Xiaoru, and Zhou, Di

Subjects
POVERTY rate, INCOME, POVERTY, ASSET allocation, LOANS, MICROFINANCE
Abstract

Digital financial inclusion has become an important way to reduce poverty and prevent poverty return; however, few studies examine the relationship between digital financial inclusion measurement with poverty return governance. Based on data from the 2017 China Household Financial Survey, we construct a digital financial inclusion indicator for micro‐households, and explore its impact on the risk of households returning to poverty and its mechanisms. Our findings suggest that digital financial inclusion can reduce the risk of Chinese families returning to poverty, and that it has heterogeneous effects on families and regions with different characteristics. The main function is to improve household income level by promoting entrepreneurship and employment, and to improve risk resistance by enhancing household financial market participation and household asset allocation. Further analysis shows that digital financial inclusion has structural effects, nonlinear effects, and substitution effects with private lending in poverty governance. This paper has implications for understanding and improving the poverty governance effectiveness of digital financial inclusion. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results