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756 results on '"Ma, Wang"'

1. Prediction of Hydrate Phase Equilibrium of Condensate Gas with High CO2 Content

Author

Jing, Pengcheng, Yu, Changhong, Xia, Yuxiang, Liang, Youran, Ma, Wang, Liu, Hongtao, Chen, Litao, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Sun, Baojiang, editor, Sun, Jinsheng, editor, Wang, Zhiyuan, editor, Chen, Litao, editor, and Chen, Meiping, editor

Published
2024
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2. Study on Methane Hydrate Detection in Gas Containing Oil Pipelines by Electrical Resistivity Test

Author

Liang, Youran, Zhang, Yuhang, Ma, Wang, Xia, Yuxiang, Jing, Pengcheng, Yu, Changhong, Xiao, Kai, Chen, Litao, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Sun, Baojiang, editor, Sun, Jinsheng, editor, Wang, Zhiyuan, editor, Chen, Litao, editor, and Chen, Meiping, editor

Published
2024
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3. Experimental Investigation on the Effect of AA + PVCap + MeOH Compound to Methane Hydrate Agglomeration in Water

Author

Ma, Wang, Lv, Fengjun, Chen, Litao, Liang, Youran, Yu, Changhong, Jing, Pengcheng, Xia, Yuxiang, di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Sun, Baojiang, editor, Sun, Jinsheng, editor, Wang, Zhiyuan, editor, Chen, Litao, editor, and Chen, Meiping, editor

Published
2024
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20. Mammography machine compression paddle movement and observer performance analysis

Author

Ma, Wang Kei

Subjects
618.1
Abstract

Full field digital mammography (FFDM) was introduced into the United Kingdom (UK) as a replacement for screen-film mammography (SFM) in 2005. Since then, individual breast screening centres have begun to report blurred images through local audits. Blurring was probably present in SFM as well, however the improvement in contrast resolution in FFDM may have made it more apparent. The sources of blurring include improper imaging techniques, patient movement caused by breathing and heart motion,the viscoelastic motion of the breast, and paddle motion. This thesis aims to test the hypothesis that paddle motion might cause image blur. It investigates whether blurring can be detected visually on technical review monitors and reporting grade monitors. The thesis presents a method to minimise paddle motion during X-ray exposure. Six papers have been published. Two of these (papers 1 and 2) investigated paddle displacement using linear potentiometers. Three investigated the influence of paddle motion on image quality. Paper 3 investigated whether paddle motion can cause image blur; paper 4 determined the minimum amount of simulated motion required for the visual detection of blurring; and paper 5 evaluated the practitioner's ability to identify blurring on monitors with different resolutions (2.3 MP and 5 MP). The final research paper (paper 6) investigated a way to reduce paddle displacement settling time; this involved the use of a closed-loop control system. Results: In papers 1 and 2 paddle displacement followed a bi-exponential function with a settling time of approximately 40 s. The use of average paddle displacement to estimate the amount of paddle motion would underestimate the worst case of the three different runs of the experiment. The estimated paddle motion would be greatly reduced if the time of exposure is delayed from 5 to 10 s. In paper 3 all metal ball bearings shown increased in diameters and the range of magnification varied from 1.04 to 1.21. T-test results shown that there was a significant difference (p < 0.05) in the ball bearing diameters between the intensity thresholding and the edge detection methods for all paddle/ compression force combinations. The ball bearing diameters calculated by the intensity thresholding method had higher variability than the edge detection method. In paper 4 the soft-edged mask method best represented the physical process that caused the blurring effect and was chosen as the standard simulation approach for motion blurring. The ratio between the vertical paddle motion and the horizontal breast motion estimated by the mathematical model is approximately 1:0.3. In paper 5 the angular size calculation shown that for a viewing distance of 75 cm the screen resolution for 5 MP and 12 MP monitors was better than the observer eyes' resolution. For a viewing distance of 30 cm the observer eyes' resolution was better than the screen resolution for 2.3 MP, 5 MP and 12 MP monitors. Among all three monitors, image displayed on the 12 MP monitor has the lowest loss in image quality after interpolation. In paper 6 the simulation results shown that force overshoot is possible for position control system. Force overshoot occurred almost instantaneously for step input and its magnitude is about 10 times larger than the ramp input. Force overshoot and steadystate error can be eliminated by the use of force control system. Conclusion: The magnitude of calculated paddle motion is much lower than the minimum amount of simulated motion required for the visual detection of blurring. Mathematical models have shown that vertical paddle motion caused a smaller horizontal breast displacement when compressed. Therefore, there is no sufficient evidence to support the hypothesis that paddle motion is a cause of image blurring in FFDM.

Published
2021

23. Diagnostic value and key features of computed tomography in Coronavirus Disease 2019.

Author

Li, Bingjie, Li, Xin, Wang, Yaxuan, Han, Yikai, Wang, Yidi, Wang, Chen, Zhang, Guorui, Jin, Jianjun, Jia, Hongxia, Fan, Feifei, Ma, Wang, Liu, Hong, and Zhou, Yue

Subjects
Lung, Humans, Pneumonia, Viral, Coronavirus Infections, Severe Acute Respiratory Syndrome, Disease Progression, Diagnosis, Differential, Tomography, X-Ray Computed, Radiography, Thoracic, Clinical Laboratory Techniques, Nucleic Acid Amplification Techniques, Pandemics, Betacoronavirus, COVID-19, SARS-CoV-2, COVID-19 Testing, Coronavirus Disease 2019, computed tomography, diagnosis, ground-glass opacity, Rare Diseases, Infectious Diseases, Vaccine Related, Clinical Research, Prevention, Pneumonia, Clinical Trials and Supportive Activities, Emerging Infectious Diseases, Biomedical Imaging, Biodefense, Detection, screening and diagnosis, 4.2 Evaluation of markers and technologies, Good Health and Well Being, Microbiology
Abstract

On 31 December 2019, a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, Hubei province, China, and caused the outbreak of the Coronavirus Disease 2019 (COVID-19). To date, computed tomography (CT) findings have been recommended as major evidence for the clinical diagnosis of COVID-19 in Hubei, China. This review focuses on the imaging characteristics and changes throughout the disease course in patients with COVID-19 in order to provide some help for clinicians. Typical CT findings included bilateral ground-glass opacity, pulmonary consolidation, and prominent distribution in the posterior and peripheral parts of the lungs. This review also provides a comparison between COVID-19 and other diseases that have similar CT findings. Since most patients with COVID-19 infection share typical imaging features, radiological examinations have an irreplaceable role in screening, diagnosis and monitoring treatment effects in clinical practice.

Published
2020

44. Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo‐Tethys Ocean.

Author

MA, Wang, LIU, Yingchao, YANG, Zhusen, HUIZENGA, Jan‐Marten, LI, Zhenqing, YUE, Longlong, and ZHAO, Sibo

Subjects
*GEOCHEMISTRY, *LHERZOLITE, *GEOLOGICAL time scales, *MAGMAS, *PETROGENESIS
Abstract

Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo‐Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc‐like geochemical signatures in a subduction‐zone tectonic setting characterized by high Al2O3 and low TiO2 contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive εNd(t) values, and the relatively high Sr‐Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo‐Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane. [ABSTRACT FROM AUTHOR]

Published
2024
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