Search

Your search keyword '"Cheng, Xiaohe"' showing total 170 results
Start Over Author "Cheng, Xiaohe"
170 results on '"Cheng, Xiaohe"'

5. Sub-THz Inline Transition From Microstrip Line to Waveguide for Large-Sized MMICs

Author

Liu, Zihao, Yao, Yuan, Liu, Zhiyan, Li, Qi, and Cheng, Xiaohe

Abstract

This article presents a wideband sub-terahertz (sub-THz) inline transition from microstrip line (MSL) to rectangular waveguide (RWG). The transition employs the bow-tie antenna to achieve a compact inline transition and wideband impedance matching with the RWG, resulting in bigger bandwidths than the transitions using dipoles. In order to overcome the substrate width limitations of conventional probes, the perfect magnetic conductor (PMC) packaging concept is used in this article, resulting in a better integration ability with large-sized monolithic microwave integrated circuits (MMICs). Two back-to-back transition prototypes related to different angles of the bow-tie antenna have been fabricated to evaluate the transition performances in the sub-THz band. The tested large-sized substrates have a large width of 10.826 mm and a length of 10.8 mm, and the length of the MSL is 9.28 mm. According to the experimental results, in the 110–170-GHz band, prototype I has a reflection coefficient of less than -11 dB and an insertion loss of 1.79–2.6 dB, while prototype II has a reflection coefficient of less than -8.5 dB and an insertion loss of 1.52–2.5 dB.

Published
2024
Full Text
View/download PDF

6. Study on coupling relationship between longitudinal wave velocity and stress of coal outburst with gas

Author

CHENG Xiaohe, SONG Dazhao, QIU Liming, WANG Honglei, WANG Anhu

Subjects
coal and gas outburst, coal and rock with gas, longitudinal wave velocity, stress, coupling mode, Mining engineering. Metallurgy, TN1-997
Abstract

In order to give an accurate warning of coal and gas outburst disaster, a triaxial compression wave velocity test system of coal and rock with gas outburst was built. The coupling relationship between the axial pressure, confining pressure, the gas pressure and wave velocity of coal and rock with gas was studied under the laboratory conditions, and the mathematical model of wave velocity and pressure was established. The results show that: when the load of the sample is constant, with the increase of the gas pressure, the longitudinal wave velocity will decrease sharply at the beginning, and then tend to be stable, showing a linear negative correlation; when the confining pressure and the air pressure conditions are constant, the wave velocity of the sample will increase rapidly after the axial pressure is applied at the beginning, and then the wave velocity tends to be flat and increases linearly, showing an exponential function relationship; when the air pressure and the confining pressure strip, with the increase of confining pressure, the longitudinal velocity of the specimen increases uniformly and linearly, and the mathematical model fitted by the three test results has a high correlation coefficient.

Published
2021
Full Text
View/download PDF

12. Research on time-frequency characteristics of acoustic-electric signals in process of rock failure under load

Author

LIU Yang, QIU Liming, LOU Quan, WEI Menghan, YIN Shan, LI Pengpeng, and CHENG Xiaohe

Subjects
coal-rock dynamic disaster, rock failure under load, uniaxial compression, acoustic emission, electromagnetic radiation, time-frequency characteristics, time-domain correlatio, Mining engineering. Metallurgy, TN1-997
Abstract

The analysis of time-domain characteristics of acoustic emission (AE) and electromagnetic radiation (EMR) signals in process of rock failure under load mostly draws qualitative conclusions from amplitude, ringing count, energy and other parameters, without directly giving time-domain correlation of AE and EMR signals, and parameters used in frequency-domain characteristics analysis of AE and EMR signals are relatively simple. In view of the above problems, monitoring experiment of AE and EMR signals of rock samples under uniaxial compression was carried out, and time-frequency characteristics of AE and EMR signals in different stages of rock failure under load were analyzed. The results show that: ① In compressionstage and elastic stage, amplitude of AE and EMR signals is basically zero. In accelerated failure stage, amplitude of AE and EMR signals increases gradually and the number of signals increases gradually. In stage of complete failure, amplitude of AE and EMR signals increases and decreases almost at the same time. When load reaches the peak value, amplitude of AE and EMR signals reaches the maximum at the same time. Amplitude of AE signal is larger than that of EMR signal in the whole process of failure under load. ② In accelerated failure stage, AE and EMR signals are significantly correlated. In stage of complete destruction, AE and EMR signals are highly correlated. In the whole process of failure underload, variation trend of AE and EMR signals with time is basically the same, and AE and EMR signals are highly correlated in time-domain. ③ In accelerated failure stage and complete failure stage, EMR signals are mainly low frequency and very low frequency signals. Compared with EMR signal, AE signal has wider frequency band and larger amplitude of main frequency. Main frequency concentration range of AE and EMR signals is similar but not completely consistent. Amplitude of main frequency of AE and EMR signals in complete failure stage is larger than that in accelerated failure stage.

Published
2020
Full Text
View/download PDF

24. An Engineered IgG–VHH Bispecific Antibody against SARS‐CoV‐2 and Its Variants (Small Methods 12/2022)

Author

Chi, Hang, primary, Wang, Lei, additional, Liu, Chanjuan, additional, Cheng, Xiaohe, additional, Zheng, Hailiang, additional, Lv, Lilang, additional, Tan, Yongcong, additional, Zhang, Nana, additional, Zhao, Suoqun, additional, Wu, Mei, additional, Luo, Dan, additional, Qiu, Hongying, additional, Feng, Rui, additional, Fu, Wangjun, additional, Zhang, Jie, additional, Xiong, Xiaochuan, additional, Zhang, Yifei, additional, Zu, Shulong, additional, Chen, Qi, additional, Ye, Qing, additional, Yan, Xintian, additional, Hu, Yuhao, additional, Zhang, Zhen, additional, Yan, Run, additional, Yin, Jiangfeng, additional, Lei, Pan, additional, Wang, Wanjing, additional, Lang, Guojun, additional, Shao, Junbin, additional, Deng, Yongqiang, additional, Wang, Xiangxi, additional, and Qin, Chengfeng, additional

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results