Search

Your search keyword '"Ma, Si-yuan"' showing total 112 results
Start Over Author "Ma, Si-yuan"
112 results on '"Ma, Si-yuan"'

6. High-speed generation of vector beams through random spatial multiplexing

Author

Hu, Xiao-Bo, Ma, Si-Yuan, and Rosales-Guzmán, Carmelo

Subjects
Physics - Optics
Abstract

Complex vector modes have become topical of late due to their fascinating properties and the many applications they have found across a broad variety of research fields. Even though such modes can be generated in a wide variety of ways, digital holography stands out as one of the most flexible and versatile. Along this line, Digital Micromirror Devices (DMDs) have gain popularity in recent time due to their high refresh rates, which allows the generation of vector modes at kHz rates. Nonetheless, most techniques are limited either by the diversity of vector modes that can be generated or by the speed at which they can be switched. Here we propose a technique based on the concept of random encoding, which allows the generation of arbitrary vector beams at speeds limited only by the refresh rate of the DMD. Our technique will be of great relevance in research fields such as optical communications, laser material processing and optical manipulation, amongst others., Comment: 9 pages, 9 figures

Published
2020
Full Text
View/download PDF

12. A Novel Method of Encoded Multiplexing Readout for Micro-pattern Gas Detectors

Author

Qi, Bin-Xiang, Liu, Shu-Bin, Ji, Heng, Shen, Zhong-Tao, Ma, Si-Yuan, Liu, Hong-Bang, Huang, Wen-Qian, and An, Qi

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The requirement of a large number of electronic channels poses a big challenge for Micro-pattern Gas Detector (MPGD) to achieve good spatial resolution. By using the redundancy that at least two neighboring strips record the signal of a particle, a novel method of encoded multiplexing readout for MPGDs is presented in this paper. The method offers a feasible and easily-extensible way of encoding and decoding, and can significantly reduce the number of readout channels. A verification test was carried out on a 5*5 cm2 Thick Gas Electron Multiplier (THGEM) detector using a 8 keV Cu X-ray source with 100um slit, where 166 strips are read out by 21 encoded readout channels. The test results show a good linearity in its position response, and the spatial resolution root-mean-square (RMS) of the test system is about 260 {\mu}m. This method has an attractive potential to build large area detectors and can be easily adapted to other detectors like MPGDs.

Published
2015
Full Text
View/download PDF

13. Onboard Calibration Circuit for the Front-end Electronics of DAMPE BGO Calorimeter

Author

Zhang, De-Liang, Feng, Chang-Qing, Zhang, Jun-Bin, Wang, Qi, Ma, Si-Yuan, Gao, Shan-Shan, Shen, Zhong-Tao, Jiang, Di, Guo, Jian-Hua, Liu, Shu-Bin, and An, Qi

Subjects
Physics - Instrumentation and Detectors
Abstract

An onboard calibration circuit has been designed for the front-end electronics (FEE) of DAMPE BGO Calorimeter. It is mainly composed of a 12 bit DAC, an operation amplifier and an analog switch. Test results showed that a dynamic range of 0 ~ 30 pC with a precision of 5 fC was achieved, which meets the requirements of the front-end electronics. Furthermore, it is used to test the trigger function of the FEEs. The calibration circuit has been implemented and verified by all the environmental tests for both Qualification Model and Flight Model of DAMPE. The DAMPE satellite will be launched at the end of 2015 and the calibration circuit will perform onboard calibration in space., Comment: 7 pages, 15 figures, 1 table

Published
2015

31. Electrospinning of aligned PVDF nanofibers with piezoelectricity and its application in pressure sensors

Author

王凌云 Wang Ling-yun, 马思远 Ma Si-yuan, and 吴德志 Wu De-zhi

Subjects
Materials science, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Piezoelectricity, Pressure sensor, Atomic and Molecular Physics, and Optics, Electrospinning, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Nanofiber, 0210 nano-technology
Published
2016

34. Quantitative EEG analysis in children with tic disorders.

Author

MA Si-yuan, FAN Xing, and QIAO Hui

Subjects
ELECTROENCEPHALOGRAPHY, FRONTAL lobe, TIC disorders, TOURETTE syndrome, RETROSPECTIVE studies, CASE-control method, MEDICAL artifacts, CHILDREN
Abstract

Objective The current study aimed to clarify quantitative electroencephalography (EEG) characteristics of children with tic disorders (TD), discuss possible mechanisms of tic disorders, and explore the application value of quantitative EEG for the diagnosis and treatment of tic disorders. Methods EEG data of 104 children with tic disorders (TD group) treated at the Department of Pediatric in Beijing Tiantan Hospital, Capital Medical University between January 2019 and December 2019 were retrospectively analyzed. EEG data were screened for specific time periods without obvious artifacts. The relative α, β, θ and δ bands energy, θ/β ratio, and spectral boundary of Fp1, Fp2, F3 and F4 were extracted. Forty-nine children matched by sex and age were randomly selected as the control group for statistical analysis. Results In comparison with the control group, children with tic disorders, Fp1, Fp2 showed higher relative θ band energy (Z = 2.354, P = 0.019; t = - 2.351, P = 0.020) and higher θ/β ratio (Z = 1.990, P = 0.047; Z = 2.206, P = 0.027), F3 showed higher relative δ band energy (t = - 2.107, P = 0.037), F4 showed higher relative θ band energy (Z = 2.342, P = 0.019), higher relative δ band energy (Z = 2.510, P = 0.012) and higher θ/β ratio (Z = 2.266, P = 0.023); Fp1, Fp2, F3 and F4 showed lower relative α band energy (Z = - 3.005, P = 0.003; Z = - 2.829, P = 0.005; Z = - 2.905, P = 0.004; Z = - 2.849, P = 0.004); F4 showed lower relative β band energy (Z = - 2.022, P = 0.043). No significant difference was identified in spectral boundary (P > 0.05, for all). Conclusions The results suggested that the primary lesion of tic disorders mainly involved the frontal cortex, and lead to brain excitation-inhibition imbalance. Quantitative EEG can provide objective evidences for the diagnosis and treatment response assessment of patients with tic disorders. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

36. On the Integration of National Fitness and Health Services for the Elderly Under National Strategy.

Author

MA Si-yuan

Abstract

Actively dealing with the problem of healthy ageing brought by China's rapid ageing population is one of the critical issues concerning national economy and people's livelihood. Through literature analysis, it is believed that the integration of national fitness and health services for the elderly has a broad social identity and policy basis, as well as a logical relationship that fitness exercises promote health, which is of great practical significance to solve the problem of healthy ageing. However, it is found through questionnaire survey and research that problems, such as weak concept of fitness, lack of fitness awareness, insufficient fitness fields and facilities and the lack of management by sports social organizations, etc., severely hinder the development of the elderly joining in the national fitness program (NFP). The unscientific method, low weekly frequency of sports and fitness and short duration of each physical exercise show the low degree of integration of the elderly into national fitness is still insufficient. The study on their relationship shows NFP and the demands of the elderly for health services are the internal and external powers of the integration. The merge of the two concepts of fitness and health, the reorganization and integration of sports tourism industry and fitness leisure industry, and the shared integration of NFP and health services for the aged form three paths of concept integration, industry integration and service integration respectively. Policy support, organization and implementation, health education and exercise environment are the important guarantees to realize the organic integration of national fitness and the health services for the elderly. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

37. Investigation on 1-heptene/air laminar flame propagation under elevated pressures†.

Author

Mei, Bo-wen, Li, Wei, Ma, Si-yuan, Wang, Hai-yu, Pan, Hao-quan, Qi, Fei, and Li, Yu-yang

Abstract

The laminar flame propagation of 1-heptene/air mixtures covering equivalence ratios from 0.7 to 1.5 is investigated in a constant-volume cylindrical combustion vessel at 373 K and elevated pressures (1, 2, 5, and 10 atm). Laminar flame speed and Markstein length are derived from the recorded schlieren images. A kinetic model of 1-heptene combustion is developed based on our previous kinetic model of 1-hexene. The model is validated against the laminar flame speed data measured in this work and the ignition delay time data in literature. Modeling analyses, such as sensitivity analysis and rate of production analysis, are performed to help understand the high temperature chemistry of 1-heptene under various pressures and its influence on the laminar flame propagation. Furthermore, the laminar flame propagation of 1-heptene/air mixtures is compared with that of n-heptane/air mixtures reported in our previous work. The laminar flame speed values of 1-heptene/air mixtures are observed to be faster than those of n-heptane/air mixtures under most conditions due to the enhanced exothermicity and reactivity. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results