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Your search keyword '"Liu, Yanwei"' showing total 542 results
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542 results on '"Liu, Yanwei"'

1. Generation of Spatially Coherent Light at Extreme Ultraviolet Wavelengths

Author

Bartels, Randy A., Paul, Ariel, Green, Hans, Kapteyn, Henry C., Murnane, Margaret M., Backus, Sterling, Christov, Ivan P., Liu, Yanwei, Attwood, David, and Jacobsen, Chris

Subjects
Physics - Optics, Physics - Atomic Physics, Quantum Physics
Abstract

We present spatial coherence measurements of extreme-ultraviolet light generated using the process of high-harmonic upconversion of a femtosecond laser. Using a phase-matched hollow-fiber geometry, the generated beam is found to exhibit essentially full spatial coherence. The coherence of this laser-like EUV source is demonstrated by recording Gabor holograms of small objects. This work demonstrates the capability to do EUV holography using a tabletop experimental setup. Such an EUV source, with low divergence and high spatial coherence, can be used for experiments such as high-precision metrology, inspection of optical components for EUV lithography (1), and for microscopy and holography (2) with nanometer resolution. Furthermore, the short time duration of the EUV radiation (a few femtoseconds) will enable EUV microscopy and holography to be performed with ultrahigh time resolution., Comment: 16 pages, 4 figures

Published
2024
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2. A compact single-shot soft X-ray photon spectrometer for free electron laser diagnostics

Author

Larsen, Kirk A., Borne, Kurtis, Obaid, Razib, Kamalov, Andrei, Liu, Yusong, Cheng, Xinxin, James, Justin, Driver, Taran, Li, Kenan, Liu, Yanwei, Sakdinawat, Anne, David, Christian, Wolf, Thomas J. A., Cryan, James, Walter, Peter, and Lin, Ming-Fu

Subjects
Physics - Instrumentation and Detectors, Physics - Optics
Abstract

The photon spectrum from free-electron laser (FEL) light sources offers valuable information in time-resolved experiments and machine optimization in the spectral and temporal domains. We have developed a compact single-shot photon spectrometer to diagnose soft X-ray spectra. The spectrometer consists of an array of off-axis Fresnel zone plates (FZP) that act as transmission-imaging gratings, a Ce-YAG scintillator, and a microscope objective to image the scintillation target onto a two-dimensional imaging detector. This spectrometer operates in an energy range which covers absorption edges associated with several atomic constituents carbon, nitrogen, oxygen, and neon. The spectrometer's performance is demonstrated at a repetition rate of 120 Hz, but our detection scheme can be easily extended to 200 kHz spectral collection by employing a fast complementary metal oxide semiconductor (CMOS) line-scan camera to detect the light from the scintillator. This compact photon spectrometer provides an opportunity for monitoring the spectrum downstream of an endstation in a limited space environment with subelectronvolt energy resolution., Comment: 14 pages, 5 figures, 1 table

Published
2023

22. Maintainability Design Based on the Analysis of the Operation Complexity Model for Extravehicular Maintenance

Author

Zhao, Zhenhao, Yin, Zhao, Yang, Jinlu, Liu, Yanwei, Ma, Shaojun, Kang, Yong, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Long, Shengzhao, editor, and Dhillon, Balbir S., editor

Published
2023
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40. Study on proppant migration and placement under sand-carrying action of clean fracturing fluid

Author

ZUO Weiqin, XIE Kunrong, HAN Hongkai, LIU Yanwei, ZHAO Fajun, and WANG Yang

Subjects
clean fracturing fluid, proppant, computational fluid dynamics, multiphase flow model, coalbed methane, Mining engineering. Metallurgy, TN1-997
Abstract

In order to explore the law of proppant migration and placement under clean fracturing fluid, an Euler multiphase flow model was established through FLUENT numerical simulation software based on computational fluid dynamics(CFD). The model takes into account the rheological properties of fracturing fluid and the friction and collision of proppant particles. The influence of proppant size, density and sand ratio on the shape of the sand dike is studied by using the equilibrium height and equilibrium time as the characterization parameters. The results show that the clean fracturing fluid is easier to carry the proppant to the depth of the fracture than the conventional fracturing fluid, so that the proppant is evenly distributed in the fracture; proppant with large particle size and high density can easily settle in the fracture opening under the carrying of the clean fracturing fluid, while proppant with small particle size and low density can improve the sand carrying capacity of fracturing fluid and transport proppant into deep fracture. Increasing sand ratio in a certain range can improve the height and laying area of the sand dike, but excessive sand ratio has little effect on the shape of the proppant sand dike and is easy to cause sand blockage.

Published
2022
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