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287 results on '"Zhang, Zhijiang"'

51. Influence of Bedding Strength and Angle on Fracture Characteristics of Sandstone under Three-Point Bending Conditions †.

Author

Wang, Guobo, Meng, Tao, Feng, Gan, Ma, Lifeng, Yang, Weimin, He, Yi, Zhang, Zhijiang, and Liang, Xufeng

Subjects
SANDSTONE, FRACTURE strength, COAL gasification, CRACK propagation (Fracture mechanics), FRACTURE toughness
Abstract

The fracture characteristics of bedded sandstone determine the stability and safety of in situ coal gasification technology. Four semicircular stratified sandstone specimens with different strengths (0.3, 0.6, 1.0, and 1.5 times that of rock matrix) and seven different bedding angles (θ = 0°, 15°, 30°, 45°, 60°, 75°, and 90°) were numerically simulated using RFPA2D-Basic V2.0 software. The SCB specimen had no prefabricated crack, and its radius was 25 mm. The loading rate was 0.000001 m/step. The results show that the fracture characteristics of the sandstone are affected by both the strength of the laminae and the angle; the fracture toughness and peak strength of the ultra-weak sandstone, as well as the weak sandstone, are reduced and more easily affected by the bedding angle; the strength rate of the strong sandstone is higher than that of the homogeneous sandstone, and the difference between the fracture characteristics of the two is not significant. This paper suggests that the key mechanism of this phenomenon is the anisotropy between the bedding and the sandstone, along with the competition/synergy between the main crack and the bedding plane bias crack during fracture propagation. These research results can provide a theoretical reference for the safety and stability of underground engineering in China. [ABSTRACT FROM AUTHOR]

Published
2023
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61. Prognosis and antibody profiles in survivors of critical illness from COVID-19: a prospective, multi-centre, cohort study

Author

Yang, Xiao, primary, Li, Zhifeng, additional, Wang, Binbin, additional, Pan, Yunbao, additional, Jiang, Chaoyun, additional, Zhang, Xingguo, additional, Yang, Yadong, additional, Zhou, Chenliang, additional, Hu, Chang, additional, Zhang, Zhijiang, additional, Xu, Haibo, additional, Liao, Weijin, additional, Vizcaychipi, Marcela P., additional, Sanders, Robert D., additional, Li, Yirong, additional, Ma, Daqing, additional, and Peng, Zhiyong, additional

Published
2021
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63. HIPK2 phosphorylates HDAC3 for NF-κB acetylation to ameliorate colitis-associated colorectal carcinoma and sepsis

Author

Zhang, Fang, primary, Qi, Linlin, additional, Feng, Qiuyun, additional, Zhang, Baokai, additional, Li, Xiangyue, additional, Liu, Chang, additional, Li, Weiyun, additional, Liu, Qiaojie, additional, Yang, Dan, additional, Yin, Yue, additional, Peng, Chao, additional, Wu, Han, additional, Tang, Zhao-Hui, additional, Zhou, Xi, additional, Xiang, Zou, additional, Zhang, Zhijiang, additional, Wang, Hongyan, additional, and Wei, Bin, additional

Published
2021
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65. Volumeter: 3D human body parameters measurement with a single Kinect

Author

Zhang Zhijiang, Yijun Ji, Dan Zeng, and He Qinzhu

Subjects
business.industry, Computer science, System of measurement, Iterative closest point, 020207 software engineering, Signed distance function, 02 engineering and technology, Tracking (particle physics), computer.software_genre, Aliasing, Voxel, Video tracking, 0202 electrical engineering, electronic engineering, information engineering, Piecewise, 020201 artificial intelligence & image processing, Computer vision, Computer Vision and Pattern Recognition, Artificial intelligence, business, computer, Software
Abstract

3D human body parameters measurement is a challenging task due to two main reasons: (i) it is difficult to reconstruct 3D human model due to flexible deformation of non-rigid body during images capturing process and (ii) there lies a gap between 3D model and body parameters. To address these two issues, a 3D human body parameters measurement system is represented. With the object freely spinning in front of a Kinect, body parameters are calculated. To reduce registration errors caused by body deformation while rotating, a piecewise tracking and mapping algorithm based on KinectFusion framework is proposed. Then model-model iterative closest point and non-rigid constraints are introduced to optimise alignments and disambiguate different surfaces caused by aliasing in the piecewise strategy. Finally, a novel method is presented to measure the volume and perimeter of human body with the truncated signed distance function values of voxels. Extensive experimental results show that the proposed method achieves comparable accuracy to the state of the arts, and the error of volume and perimeter measurements are 2.0 and 5.8%, respectively.

Published
2018
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70. Three-dimensional measurement with use of a single camera

Author

Zhang, Zhijiang and Pan, Zhihao

Subjects
Astronomy, Physics
Abstract

A new, to our knowledge, measurement technique that uses a single image of a handheld probe on known points, to measure geometric features of an object, is discussed in detail. A new method is also proposed to calculate three-dimensional coordinates of points on the object relative to a reference. Furthermore, the validity of the proposed measuring system is confirmed by experiments. OCIS codes: 150.3040, 330.4060.

Published
2004

78. An Online Measurement Method for Insulator Creepage Distance on Transmission Lines

Author

Zhang Zhijiang, Dan Zeng, Huang Jing, and Kejian Liu

Subjects
010302 applied physics, error correction, Control and Optimization, Renewable Energy, Sustainability and the Environment, Computer science, lcsh:T, 020209 energy, Total station, Energy Engineering and Power Technology, Insulator (electricity), 02 engineering and technology, creepage distance, 01 natural sciences, lcsh:Technology, Electric power system, Electric power transmission, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, features, insulators, Electrical and Electronic Engineering, Engineering (miscellaneous), Energy (miscellaneous)
Abstract

Insulators play a crucial role in ensuring the normal operation of the power system, and the creepage distance is an important electrical parameter of insulators. Most available solutions focus mainly on offline measurement methods, and online measurement for insulator creepage distance on transmission lines remains a challenging task. To address this issue and to further improve the corresponding work efficiency, an online measurement method for insulator creepage distance is presented in this paper. Considering the glass material of the insulator and the long measuring distance, this method recognizes the insulator type indirectly by calculating the structural parameters of the insulators based on their geometric features, and then obtaining the creepage distance. Accordingly, a measurement system, which mainly includes an electronic total station and a camera with a telephoto lens, is designed in this paper. Moreover, this paper also proposes an error analysis model aimed at reducing the errors caused by the layout of this system. In the conducted experiments, this proposed method effectively obtains the creepage distance and the error correction model can further improve the measurement accuracy of structural parameters.

Published
2018

86. Study and Implementation on the Monitor of Liquid Level of Liquid Scintillator

Author

Zhang Zhijiang, Zhu Shiheng, Xu Xiangmin, and Yang Lie

Subjects
Materials science, Physics::Instrumentation and Detectors, business.industry, Infrared, Liquid level measurement, Image processing, Image segmentation, Scintillator, Physics::Fluid Dynamics, Condensed Matter::Soft Condensed Matter, Optics, Industrial PC, Calibration, business, Engine control unit
Abstract

This paper presents a method to monitor the liquid level of liquid scintillator which satisfies the requirement of one neutrino experiment. It uses auxiliary infrared LED source and infrared CCD camera to realize non-contact detection of liquid level. Firstly, it is verified that the infrared LED source has no effect on PMT in the liquid scintillator. Then a monitor system of liquid level is designed by industrial PC, power control module, infrared LED source, calibration tube and infrared CCD camera etc. At last, using image preprocessing, image segmentation, liquid level positioning and liquid level measurement and other image processing techniques, the measurement of liquid level of liquid scintillator meets the requirement and the error is within ±2mm.

Published
2017
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87. Low‐rank matrix fitting based channel estimation for full‐dimensional massive MIMO systems.

Author

Xu, Yaning, Du, Weimin, Fan, Yining, and Zhang, Zhijiang

Subjects
MIMO systems, WIRELESS communications, LOW-rank matrices, CHANNEL estimation, DATA transmission systems
Abstract

Full‐dimensional (FD) massive MIMO can overcome the limitation of the physical space at the base station (BS) and meet the increasing capacity requirement for future wireless communications. However, the pilot overhead for the acquisition of the channel state information (CSI) at the BS could be prohibitively high due to the large number of antennas. In this letter, exploiting the Kronecker property of the channel, we propose a low‐rank matrix fitting based channel estimation (LMFCE) scheme to reduce the pilot overhead in FD massive MIMO systems. The simulation results illustrate that the proposed LMFCE scheme can significantly reduce the pilot overhead for the channel estimation. [ABSTRACT FROM AUTHOR]

Published
2022
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88. Dimension Measurement and Key Point Detection of Boxes through Laser-Triangulation and Deep Learning-Based Techniques.

Author

Peng, Tao, Zhang, Zhijiang, Chen, Fansheng, and Zeng, Dan

Subjects
PROJECTORS, MAXIMUM likelihood statistics, DIMENSIONS, BOXES, EYE, DEEP learning, TRIANGULATION
Abstract

Dimension measurement is of utmost importance in the logistics industry. This work studies a hand-held structured light vision system for boxes. This system measures dimension information through laser triangulation and deep learning using only two laser-box images from a camera and a cross-line laser projector. The structured edge maps of the boxes are detected by a novel end-to-end deep learning model based on a trimmed-holistically nested edge detection network. The precise geometry of the box is calculated by the 3D coordinates of the key points in the laser-box image through laser triangulation. An optimization method for effectively calibrating the system through the maximum likelihood estimation is then proposed. Results show that the proposed key point detection algorithm and the designed laser-vision-based visual system can locate and perform dimension measurement of measured boxes with high accuracy and reliability. The experimental outcomes show that the system is suitable for portable automatic box dimension online measurement. [ABSTRACT FROM AUTHOR]

Published
2020
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