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64. Cathode Materials for Sodium-Ion Batteries

Author

Guo, Xin, primary, Wang, Shijian, additional, Gao, Hong, additional, Zang, Rui, additional, Zhang, Xiaogang, additional, Yang, Jian, additional, Wang, Chengyin, additional, and Wang, Guoxiu, additional

Published
2023
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65. Optical-Clock-Based Time Scale

Author

Yao, Jian, Sherman, Jeff A., Fortier, Tara, Leopardi, Holly, Parker, Thomas, McGrew, William, Zhang, Xiaogang, Nicolodi, Daniele, Fasano, Robert, Schäffer, Stefan, Beloy, Kyle, Savory, Joshua, Romisch, Stefania, Oates, Chris, Diddams, Scott, Ludlow, Andrew, and Levine, Judah

Subjects
Physics - Applied Physics
Abstract

A time scale is a procedure for accurately and continuously marking the passage of time. It is exemplified by Coordinated Universal Time (UTC), and provides the backbone for critical navigation tools such as the Global Positioning System (GPS). Present time scales employ microwave atomic clocks, whose attributes can be combined and averaged in a manner such that the composite is more stable, accurate, and reliable than the output of any individual clock. Over the past decade, clocks operating at optical frequencies have been introduced which are orders of magnitude more stable than any microwave clock. However, in spite of their great potential, these optical clocks cannot be operated continuously, which makes their use in a time scale problematic. In this paper, we report the development of a hybrid microwave-optical time scale, which only requires the optical clock to run intermittently while relying upon the ensemble of microwave clocks to serve as the flywheel oscillator. The benefit of using clock ensemble as the flywheel oscillator, instead of a single clock, can be understood by the Dick-effect limit. This time scale demonstrates for the first time sub-nanosecond accuracy for a few months, attaining a fractional frequency uncertainty of 1.45*10-16 at 30 days and reaching the 10-17 decade at 50 days, with respect to UTC. This time scale significantly improves the accuracy in timekeeping and could change the existing time-scale architectures.

Published
2019
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81. Analysis of Mineralogical Characteristics of Leucosphenite from the Fengcheng Formation in the Junggar Basin by Electron Probe Microanalyzer and X-ray Diffractometer

Author

LIU Jin, WANG Jian, WANG Guijun, ZHANG Xiaogang, and SHANG Ling

Subjects
leucosphenite, electron probe microanalyzer, x-ray diffractometer, fengcheng formation, junggar basin, Geology, QE1-996.5, Ecology, QH540-549.5
Abstract

BACKGROUND Leucosphenite, a borosilicate mineral with a biaxial monoclines crystal structure, is a typical hydrothermal mineral. The mineralogy of leucosphenite in the shale of the Fengcheng Formation in the Junggar Basin in China has not been studied, and its genesis is not clear. OBJECTIVES To understand the mineralogical characteristics of leucosphenite in the Fengcheng Formation and its genesis. METHODS Electron probe microanalysis (EPMA), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyze the mineral composition and crystal structure. RESULTS The crystal size of the leucosphenite in the Fengcheng Formation is at micron scale, and the morphology is plate-like or short columnar. Leucosphenite is associated with reedmergnerite. Leucosphenite is composed of 12.64% BaO, 13.47%TiO2, 10.69% Na2O, 53.46% SiO2, and 10.11% B2O3. Crystal planes corresponding to d=4.22(-220), d=8.45(-110), d=3.37(-112) are the three most developed planes. CONCLUSIONS The element composition and crystal diffraction characteristics of leucosphenite in the Fengcheng Formation are consistent with that found abroad, but the former is richer in B. Due to the obvious positive correlation between B content and salinity in the hydrothermal fluid, the leucosphenite of the Fengcheng Formation was formed in the hydrothermal fluid with higher salinity. Deep hydrothermal fluids intruded into the shale of the Fengcheng Formation, forming reedmergnerite and leucosphenite in turn.

Published
2022
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