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1.
R. J. Saykally K. M. Evenson D. A. Jennings L. R. Zink A. Scalabrin 《International Journal of Infrared and Millimeter Waves》1987,8(6):653-662
Twenty new cw FIR laser lines in CD3OH, optically pumped by a CO2 laser, are reported. The frequencies of 39 of the stronger laser lines were measured relative to stabilized CO2 lasers with a fractional uncertainty, as determined by the reproducibility of the FIR frequency itself, of 2 parts in 107.Contribution of the U.S. Government, not subject to copyright. 相似文献
2.
The XYZ model describes the interaction between nuclear probes and an electric field gradient that fluctuates among three orthogonal
directions. The model presents a means to calculate the perturbation function that represents spectra obtained using perturbed
angular correlation spectroscopy. Three analytic approximations of the perturbation function have been developed previously,
and they are evaluated in the present paper in the context of Cd jumping among In-lattice sites in In3La. 相似文献
3.
M. Schneider A. Hinz A. Groh K. M. Evenson W. Urban 《Applied physics. B, Lasers and optics》1987,44(4):241-245
Frequency stabilization of the CO laser using a CO lamb-dip is achieved in the range from 5.0–6.3 m. The CO saturation signal is obtained from a low-pressure discharge in absorption and is detected using optogalvanic, detection. The frequency stability and reproducibility has been verified to be better than 100 kHz; this is an improvement of more than one order of magnitude compared with locking techniques using CO laser gain profiles.Alexander von Humboldt Awardee from National Bureau of Standards, Boulder, Colorado, USA 相似文献
4.
5.
E. C. C. Vasconcellos K. M. Evenson 《International Journal of Infrared and Millimeter Waves》1985,6(11):1157-1167
We have obtained laser action on 34 far infrared lines for the first time in fully deuterated methyl alcohol with the13C isotope (13CD3OD), and we have measured the frequency of 13 lines. The molecule was pumped by a cw CO2 laser. We have measured the wavelength, the relative polarization, the relative intensity of most lines, the frequency, and the CO2 pump frequency offset of the strongest lines. The new lines are distributed in the wavelength region from 75.27 m to 464.7 m.Supported in part by a joint grant with the U.S. National Science Foundation grant # INT 80-19014 and the Brazilian Conselho Nacional de Pesquisas (CNPq). 相似文献
6.
E. C. C. Vasconcellos A. Scalabrin F. R. Petersen K. M. Evenson 《International Journal of Infrared and Millimeter Waves》1981,2(3):533-539
Twenty-four new submillimeter laser lines in fully deuterated methyl alcohol (CD3OD) in the wavelength range from 52 to 328 m have been obtained in a Fabry-Perot FIR resonator by optically pumping the methanol with a cw CO2 laser. We have made accurate wavelength measurements and have determined the relative polarization of most of the known CD3OD laser lines. The frequencies of 13 of the strongest lines were also measured.Contribution of the U.S. Government, not subject to copyright. 相似文献
7.
Tahira Foyzun Abdullah Al Mahmud Md. Salim Ahammed Md. Imran Nur Manik Md. Kamrul Hasan KM Monirul Islam Simin Sobnom Lopa Md. Yusuf Al-Amin Kushal Biswas Mst. Rejina Afrin AHM Khurshid Alam Golam Sadik 《Molecules (Basel, Switzerland)》2022,27(3)
Neurotoxicity is a serious health problem of patients chronically exposed to arsenic. There is no specific treatment of this problem. Oxidative stress has been implicated in the pathological process of neurotoxicity. Polyphenolics have proven antioxidant activity, thereby offering protection against oxidative stress. In this study, we have isolated the polyphenolics from Acacia nilotica and investigated its effect against arsenic-induced neurotoxicity and oxidative stress in mice. Acacia nilotica polyphenolics prepared from column chromatography of the crude methanol extract using diaion resin contained a phenolic content of 452.185 ± 7.879 mg gallic acid equivalent/gm of sample and flavonoid content of 200.075 ± 0.755 mg catechin equivalent/gm of sample. The polyphenolics exhibited potent antioxidant activity with respect to free radical scavenging ability, total antioxidant activity and inhibition of lipid peroxidation. Administration of arsenic in mice showed a reduction of acetylcholinesterase activity in the brain which was counteracted by Acacia nilotica polyphenolics. Similarly, elevation of lipid peroxidation and depletion of glutathione in the brain of mice was effectively restored to normal level by Acacia nilotica polyphenolics. Gallic acid methyl ester, catechin and catechin-7-gallate were identified in the polyphenolics as the major active compounds. These results suggest that Acacia nilotica polyphenolics due to its strong antioxidant potential might be effective in the management of arsenic induced neurotoxicity. 相似文献
8.
We report on a procedure developed to create stochastic models of hyperfine interactions for complex diffusion mechanisms and demonstrate its application to simulate perturbed angular correlation spectra for the divacancy and 6-jump cycle diffusion mechanisms in L12-structured compounds. 相似文献
9.
We synthesized tunable far-infrared radiation at frequencies higher than 9 THz (300 cm (-1)) by mixing CO(2) laser, (15)NH(3) laser, and microwave radiation in a W-Co metal-insulator-metal diode. We used this farinfrared radiation to accurately measure torsion-rotation transitions of CH(3)OH in the 8-9-THz region. We also measured the frequency of the aP(7, 3) (15)NH(3) laser transition. 相似文献
10.
Evenson William E. Lu Jun Winz Michele W. Gardner John A. Zacate Matthew O. Lee Teresa Mommer Niels 《Hyperfine Interactions》1999,120(1-8):427-431
In order to explain PAC data for tetragonal zirconia at temperatures between 900 and 1300oC, we have developed a four-state
stochastic model. The model simulates vacancies which trap and detrap at a PAC probe nucleus. While trapped, the vacancies
hop around the probe in equivalent sites. The four states in this Winkler–Gerdau stochastic theory are three trapped states
with equivalent electric field gradients (EFGs) of different orientations and a detrapped state with a weaker EFG whose axis
of symmetry is oriented along the diagonal between the three trapped EFGs. There are three hopping rates in this model: w,
the rate a trapped vacancy hops around the probe, wD, the detrapping rate, and wt, the trapping rate. We report results of calculations for values of these hopping rates implied by our tetragonal zirconia
data, and we report heuristic fitting functions which summarize the computer results and can be used to fit data efficiently
for a wide range of parameters.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献