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The Ramsey fringes on the ground-state hyperfine transition of 199Hg+ (ΔF = 1, Δmf = 0) ions trapped in a hyperbolic Paul trap are firstly observed with the method of time-separated oscillatory fields. The full width at half maximum of central Ramsey fringes is about 25mHz and the corresponding quality factor Q of the line is greater than 1012 for the trapped 199Hg+ microwave frequency standard. The hyperfine transition frequency shifted by magnetic field is also measured by the high-resolution Ramsey fringes. The final result is Δvhfs = 40507347997.3(0.5) Hz, which is corrected to zero magnetic field. [ABSTRACT FROM AUTHOR]

In the microwave 199Hg+ trapped-ion clock, the frequency instability degradation caused by the Dick effect is unavoidable because of the periodical interrogating field. In this paper, the general expression of the sensitivity function g(t) to the frequency fluctuation of the interrogating field with Nπ-pulse (N is odd) is derived. According to the measured phase noise of the 40.5-GHz microwave synthesizer, the Dick-effect limited Allan deviation of our 199Hg+ trapped-ion clock is worked out. The results indicate that the limited Allan deviations are about and respectively in the linear ion trap and in the two-segment extended linear ion trap under our present experimental parameters. [ABSTRACT FROM AUTHOR]

We propose a method to determine the optimal power of the microwave resonance transition that simultaneously improves the signal-to-noise ratio and reduces line width based on saturation broadening theory and experiment. Saturation broadening spectra of the ground state hyperfine transition of trapped 199Hg+ ions are measured and analyzed. The value of the optimal microwave power is obtained by using the proposed method and is verified. Rabi oscillations decay spectra of trapped 199Hg+ ions are observed and the optimal microwave irradiation time for the maximum transition signal intensity is determined. This work will help to improve the short-term frequency stability of the mercury ion microwave frequency standard. [ABSTRACT FROM AUTHOR]

We report a spectroscopy experiment of the 199Hg+ ground state hyperfine splitting in a linear ion trap. The ions are optically pumped by a discharge lamp and cooled by helium buffer gas. The ground state hyperfine splitting is measured to be 40507347996.8(0.1) Hz by the microwave-optical double-resonance method. A narrow line width as 30 mHz is also observed. This progress builds the foundation for the realization of trapped 199Hg+ ion frequency standards. [ABSTRACT FROM AUTHOR]

Astragalus membranaceus var. mongholicus and Hedysarum polybotrys belong to different genera, but have similar drug efficacy in traditional Chinese medicine theory, and H. polybotrys was used as the legal A. membranaceus var. mongholicus previously. In this study, similarities and differences between them were analyzed via their ITS/ITS2 fragments information. The ITS (internal transcribed spacer) regions were amplified using polymerase chain reaction and then sequenced in two-way. The alignment lengths of ITS regions were 616 bp, in which 508 loci were consistent, and 103 loci were different, accounting for 82.47% and 16.72% of the total ITS nucleotides in length, respectively. As genotype determines phenotype, 1HNMR-based metabolomic approach was further used to reveal the chemical similarities and differences between them. Thirty-four metabolites were identified in the 1H NMR spectra, and twenty-seven metabolites were the common components. Amino acids, carbohydrates and other primary metabolites were similar, while a large difference existed in the flavonoids and astragalosides. This study suggests that A. membranaceus var. mongholicus and H. polybotrys show similarities and differences from molecular and chemical perspectives, which has laid a foundation for elucidating the effective material basis of drug with similar efficacy and resources utilization.