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1.
J. Kobayashi Y. Izumi M. Kumakura Y. Takahashi 《Applied physics. B, Lasers and optics》2006,83(1):21-25
By stabilizing the beam pointing of optical trapping beams, we have succeeded in stable formation of Bose–Einstein condensate
(BEC) of 87Rb with all-optical method. The thermal effect of acousto-optic modulator (AOM) is usually one of the most serious problems
to induce beam-pointing instability, especially for high power CO2 laser. By passing the beam through AOM twice, we have improved the beam pointing from about 4.8 mrad to less than 0.4 mrad,
which has been experimentally confirmed to be small enough to stably form BEC at the crossed region of CO2 lasers as well as to perform experiments using an optical lattice which might have been affected by beam-pointing instability.
PACS 32.80.Pj; 42.79.Jq; 03.75.Mn 相似文献
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Hiroshi Yamauchi Keiko Takahashi Mari Mashiko Juichiro Saitoh Yukio Yamamura 《应用有机金属化学》1992,6(4):383-388
We calculated the intake of each chemical species of dietary arsenic by typical Japanese, and determined urinary and blood levels of each chemical species of arsenic. The mean total arsenic intake by 35 volunteers was 195±235 (15.8-1039) μg As day?1, composed of 76% trimethylated arsenic (TMA), 17.3% inorganic arsenic (Asi), 5.8% dimethylated arsenic (DMA), and 0.8% monomethylated arsenic (MA): the intake of TMA was the largest of all the measured species. Intake of Asi characteristically and invariably occurred in each meal. Of the intake of Asi, 45-75% was methylated in vivo to form MA and DMA, and excreted in these forms into urine. The mean measured urinary total arsenic level in 56 healthy volunteers was 129±92.0 μg As dm?3, composed of 64.6% TMA, 26.7% DMA, 6.7% Asi and 2.2% MA. The mean blood total arsenic level in the 56 volunteers was 0.73±0.57 μg dl?1, composed of 73% TMA, 14% DMA and 9.6% Asi. The urinary TMA levels proved to be significantly correlated with the whole-blood TMA levels (r = 0.376; P<0.01). 相似文献
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The present paper gives a more complete treatment of the scattering from a two-dimensional random surface than previous works. Reciprocal theorems for the stochastic wave field and the incoherent scattering distribution (bistatic cross section) are derived and the presence of backscattering enhancement in the case of a slightly random Neumann surface is demonstrated. A physical interpretation of the backscattering enhancement associated with the presence of anomalous scattering on a slightly random Neumann surface is given. Some numerical calculations are performed to show the incoherent scattering distribution and the backscattering enhancement. 相似文献
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Cytotoxic activity of marine algae and a cytotoxic principle of the brown alga Sargassum tortile. 总被引:1,自引:0,他引:1
A Numata S Kanbara C Takahashi R Fujiki M Yoneda E Fujita Y Nabeshima 《Chemical & pharmaceutical bulletin》1991,39(8):2129-2131
Partition fractions of hexane, CCl4 and CHCl3 from methanolic extracts of marine algae were each examined for cytotoxic activities against cultured P-388 lymphocytic leukemia cells. Cytotoxic activities were found for partition fractions of 21 species of seaweed. Bioactivity-guided fractionation of the CCl4 partition fraction from Sargassum tortile, exhibiting the most prominent activity, afforded dihydroxysargaquinone (1) and sargatriol (2) previously isolated from this alga. The former was evaluated as a cytotoxic principle, and the latter, showing moderate activity, was suggested to be an artifact derived from 1 during the isolation procedure. 相似文献
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The peroxyoxalate chemiluminescence(CL) detection method for the evaluation of the CL intensity of malondialdehyde(MDA) condensates with seven 2-thiobarbituric acid derivatives is described. The method consists of a flow injection technique together with a CL detection system using bis(2,4,6-trichlorophenyl) oxalate(TCPO) and hydrogen peroxide as chemiluminogenic reagents. Linear correlations between CL intensity and concentration are obtained for pmol levels of condensates. Among the condensates, 1,3-diethyl-2-thiobarbituric acid(DETBA)-MDA shows the largest CL intensity. High performance liquid chromatography (HPLC)/CL detection of DETBA-MDA and 1,3-diphenyl-2-thiobarbituric acid(DPTBA)-MDA using a mixture of TCPO and hydrogen peroxide in acetonitrile as a postcolumn reagent solution is also described. The detection limits for DETBA-MDA and DPTBA-MDA are 20 and 200 fmol, respectively, per 20 microL injection at a signal-to-noise ratio of 2. This HPLC/CL detection system was applied to the determination of MDA in rat brains by using DETBA as a fluorescent derivatizing reagent. 相似文献
10.
Yamada Kaoru Matsutani Shigeaki Uchiyama Akira Takahashi Toshio 《Journal of inclusion phenomena and macrocyclic chemistry》1991,11(1):49-54
Analyses of crown ether complexes of alkali metal ions and characterization of the complexes formed inm-nitrobenzyl alcohol have been carried out by fast atom bombardment (FAB) mass spectrometry. By using m-nitrobenzyl alcohol as a matrix for measurements, the stoichiometry of the complexes was assessed on the basis of the observed FAB peaks. In addition, the formation of crown ether-alkali metal complexes at a 2 : 1 molar ratio was enhanced by increasing the ionic radius of the metal ion in agreement with previous observations. On these grounds, FAB mass spectrometry may provide a rapid means for investigation of the complexation behavior of crown ethers and the stoichiometry of the complexes. 相似文献