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Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A
two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum
distillation of the total oil. Step two was a medium pressure LC separation with an AgNO3 impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related
sesquiterpene alcohols (75% of the oil). 相似文献
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S. A. Babin D. V. Churkin A. E. Ismagulov S. I. Kablukov E. V. Podivilov 《Laser Physics》2007,17(11):1279-1285
Intracavity and output spectra broadened in a Raman fiber laser with a low-Q cavity are measured and theoretically described. It is demonstrated that the previously developed approach of optical-wave turbulence can be used to describe the spectral broadening owing to the multiple four-wave mixing processes that involves numerous longitudinal modes of the low-Q cavity. The theoretically calculated spectra are in good agreement with the experimental data for various output reflection coefficients of the fiber Bragg gratings across the entire power range. 相似文献
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Spectral broadening in Raman fiber lasers 总被引:1,自引:0,他引:1
We present an analytical theory based on wave kinetic equations that describes a Raman fiber laser (RFL) generation spectrum. It is shown both theoretically and experimentally that the quasi-degenerate four-wave mixing between different longitudinal modes is the main broadening mechanism in the one-stage RFL at high powers. The shape and power dependence of the intracavity Stokes wave spectrum are in excellent quantitative agreement with predictions of the theory. 相似文献
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A. Sosa E. Bravin J. Harasimowicz A. Jeff C. P. Welsch The AEḡIS collaboration 《Hyperfine Interactions》2014,229(1-3):169-174
Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE \(\bar {g}\) IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE \(\bar {g}\) IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented. 相似文献
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The output characteristics of the conventional one-stage Raman fiber laser (RFL) are described in an optical wave turbulence formalism. Simple analytical expressions describing RFL output power and its spectral shape are presented, and square-root law for the output spectrum broadening law has been discovered. The indications of the turbulent-like spectral broadening in other types of cw fiber lasers and propagation phenomena in fibers are also discussed. 相似文献
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Modulation instability at propagation of narrowband 100-ns pulses in optical fibers of various types
S. A. Babin A. E. Ismagulov E. V. Podivilov M. P. Fedoruk I. S. Shelemba O. V. Shtyrina 《Laser Physics》2010,20(2):334-340
The instability of the propagation of narrowband 100-ns laser pulses in the transparency window of a single-mode fiber in
the presence of continuous broadband noise is demonstrated. The modulation instability developed due to the nonlinearity and
anomalous dispersion leads to a rapid decay of the narrowband component after passing through the fiber. The modulation-instability
threshold is shown to be sensitive to the noise level in a spectral interval of about 100 GHz near a central wavelength of
about 1.55 μm and is inversely proportional to the fiber length (varied from 1.6 to 21.0 km in the experiments). The effect
is completely eliminated owing to the application of a dispersion-shifted fiber with normal dispersion. 相似文献