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71.
The extinction coefficient of a birefringent optical fiber (the ratio between the radiation power output of the polarization mode and the radiation power transferred from this mode to another one) characterizes the capability of a birefringent fiber to retain the polarization state of the radiation. In relatively short birefringent fibers (1–100 m), the extinction coefficient may reach 104–106. Such high values of the extinction coefficient are difficult to measure by standard techniques (excitation of one polarization mode by an incoherent source with subsequent recording of the light intensity at the output of the analyzer). An interference method of measuring the extinction coefficient of birefringent fibers is suggested. It is based on using a coherent source and measuring interference oscillations caused by an additional phase modulation at the input of the fiber. This method does not require precise polarization matching between the laser source and fiber and considerably loosens requirements for the polarizer-analyzer extinction and resolution of the photodetector. As a result, using simple standard components (semiconductor laser, film polarizer, and photodetector), one can measure extinction coefficient as high as 106. The suggested interference method of measuring the extinction coefficient of birefringent fibers receives a theoretical analysis, and experimental data obtained for 2- to 1000-m-long fibers are presented. 相似文献
72.
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74.
P. A. Buikin A. Yu. Rudenko A. E. Baranchikov A. B. Ilyukhin V. Yu. Kotov 《Russian Journal of Coordination Chemistry》2018,44(6):373-379
The following bromobismuthates of organic cations (dipyridinoalkane derivatives) are synthesized and characterized: (4-NH2PyC5)BiBr5 (I), (2-MePyC2)BiBr5 (II), (2-NH2PyC10)BiBr5 · 0.65H2O (III), (2-NH2PyC10)4H5O2(BiBr6)3 (IV), (2-NH2PyС6)2KBi2Br11 (V), (2-NH2PyC6)H3OBiBr6 · 2.33H2O (VI), and (2-NH2PyC6)3(BiBr6)2 · CH3CN (VII). Three compounds obtained (I–III) contain the zigzag 1D chain (BiBr5) n . A new type of 1D chains, (KBi2Br11) n , is found in the structure of compound V. Pseudo-1D chains of BiBr63? anions can be observed in the 3D structures of compounds IV, VI, and VII. The crystallographic data were deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC 1569478 (I)–1569484 (VII), respectively). 相似文献
75.
J. Badier J. Boucrot J. Bourotte G. Burgun O. Callot Ph. Charpentier M. Crozon D. Decamp P. Delpierre P. Espigat B. Gandois R. Hagelberg M. Hansroul Y. Karyotakis W. Kienzle P. Le D? J. Lefran?ois Th. Leray J. Maillard A. Michelini Ph. Mine G. Rahal O. Runolfsson P. Siegrist A. Tilquin J. Valentin R. Vanderhaghen S. Weisz NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1981,11(3):195-202
From π- interactions at 150 GeV/c on a heavy target, we present the final analysis of the dimuon decay angular distribution in the mass interval 4.5–8.5 GeV/c2. Results are presented and discussed in various reference frames and are also given in terms of the density matrix elements. Finally the possible contribution of higher-twist effects at largex 1 is discussed; we find that our data are not compatible with higher twist contributions as proposed by the Berger and Brodsky Model. 相似文献
76.
Telomerization of tetrafluoroethylene (TFE) with methanol in the presence of a free-radical initiator such as α, α′-azoisobutyronitrile
(AIBN) has been carried out. The product composition was related to kinetic equations involving the chaintransfer coefficients
and the concentration of telomeric fluoroalkanols obtained. 相似文献
77.
78.
V. O. Golub V. V. Kotov Yu. A. Podyelets A. N. Pogorely 《Hyperfine Interactions》1990,59(1-4):293-296
Additional spin-ocho signale from quadrupole nuclei with I=7/2 (Co59 nuclei in Co and Fe−Co thin films) were investigated. It has been shown, that the time dependence of the additional ocho
signals, arising at the time moments 2nς reflect quadrupole interaction inhomogenety. 相似文献
79.
Amorphous silver, copper, gold, and iron films of a thickness between 6 and 350 nm are grown on polymeric substrates by vacuum
evaporation. The nanostructure of the films is investigated. The dependence of the conductivity on the film thickness is obtained,
and a correlation between the surface morphology and the conductivity is established. 相似文献
80.
Zhi NA Bei JIANG Hui YANG Zhong Wen LIN Han Dong SUN* Laboratory of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming Chemistry Deparment of the College of Life Science Chemistry Yunnan University K 《中国化学快报》2001,(8)
Isodon enanderianus (Hand. -Mazz.) H. W. Li, has been used in folk medicine as anti-inflammatory and detoxified agent1. The Isodon genus is known to be rich in ent-kaurane diterpenoids, a series of new ent-kaurane diterpenoids have been isolated from the dried leaves of I. enanderianus2-4. In order to find more biologically active substances, we have carefully investigated the chemical constituents of I. enanderianus collected in Shiping county of Yunnan province, and as a result, enanderi… 相似文献