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排序方式: 共有195条查询结果,搜索用时 15 毫秒
11.
Emmanuel Beyou Pierre Babin Bernard Bennetau Jacques Dunogues Dominique Teyssie Sylvie Boileau 《Journal of polymer science. Part A, Polymer chemistry》1994,32(9):1673-1681
Unsaturated perfluoroalkyl esters derived from undecylenic acid: CH2?CH? (CH2)8? COO? CH2? CH2? RF (with RF?C6F13, 2a and RF?C8F17, 2b ) and C8F17? (CH2)10? COO? CH2? CH?CH2, 2c were prepared with excellent yields. Their hydrosilylation by methylhydrodimethylsiloxane copolymers of various Si? H contents gives new fluorinated polysiloxanes which were examined by 1H- and 13C-NMR, GPC, differential scanning calorimetry, and optical polarizing microscopy. Polymers derived from compounds 2a and 2b exhibit mesomorphic structures. © 1994 John Wiley & Sons, Inc. 相似文献
12.
Bis(trimethylsilyl) peroxide can be readily obtained by reaction of trimethylchlorosilane with the hexamethylenetetramine-hydrogene peroxide complex. 相似文献
13.
A. A. Babin D. V. Kartashov A. M. Kiselev V. V. Lozhkarev A. M. Sergeev A. A. Solodov A. N. Stepanov 《JETP Letters》2002,76(9):548-552
The propagation of an intense (I≤106 W/cm2) femtosecond laser radiation with a duration of ~100 fs through gas-filled dielectric capillaries was studied. The radiation with a power up to 0.2 TW propagates along the paths up to 20 cm with a transmission efficiency of ~45%. The beam transverse structure at the output is close to the capillary fundamental mode under gas-ionization conditions. The transformation of pulse spectrum was studied as a function of input intensity. It is demonstrated experimentally that the pulse is compressed to a duration of ~30 fs due to the compensation of ionization-induced self-phase modulation in a linear dispersive element at the capillary output. 相似文献
14.
Emission and excitation spectra, luminescence polarization and decay kinetics have been studied for CsI:Pb crystals in the 0.36-300 K temperature range. The origin of the excited states responsible for the optical characteristics has been discussed. It has been concluded that the doublet ≈3.70 eV absorption (excitation) band is caused by the electronic transitions into the Pb2+ triplet state split due to the presence of a cation vacancy near a Pb2+ ion, while the higher-energy bands are of the charge-transfer origin. Like in CsI:Tl, four emission bands of CsI:Pb have been found to belong to the main luminescence centres. Two emission bands, peaking at 3.1 and 2.6 eV, are suggested to arise from the triplet relaxed excited state of a Pb2+ ion. Two visible emission bands, peaking at 2.58 and 2.23 eV, are interpreted as the luminescence of an exciton localized near the Pb2+ ion. 相似文献
15.
The resonance wavelength of the fiber Bragg gratings (FBGs) is tuned using two methods. Tunable FBGs are used as the selecting elements in the cavities of tunable lasers. An ytterbium-doped fiber laser with a wavelength tuning range of 1063–1108 nm and an output power of 6 W, a Raman fiber laser with a wavelength tuning range of 1252–1303 nm and an output power of 3 W, and an erbium-doped fiber laser with a wavelength tuning range of 1530–1580 nm are realized, and their characteristics are studied. 相似文献
16.
S. A. Babin D. V. Churkin S. I. Kablukov A. S. Kurkov M. A. Nikulin 《Laser Physics》2007,17(11):1292-1295
A single-frequency all-fiber laser source operating at 1093 nm with an output power of more than 1 W is developed. A master oscillator-power amplifier configuration that comprises a distributed-feedback fiber laser and an ytterbium-doped fiber amplifier is implemented. Some aspects of the stimulated Brillouin scattering specific to active fiber are discussed. 相似文献
17.
At 4.2-350 K, the steady-state and time-resolved emission and excitation spectra and luminescence decay kinetics were studied under excitation in the 2.5-15 eV energy range for the undoped and Ce3+-doped Lu3Al5O12 (LuAG) single-crystalline films grown by liquid phase epitaxy method from the PbO-based flux. The spectral bands arising from the single Pb2+-based centres were identified. The processes of energy transfer from the host lattice to Pb2+ and Ce3+ ions and from Pb2+ to Ce3+ ions were investigated. Competition between Pb2+ and Ce3+ ions in the processes of energy transfer from the LuAG crystal lattice was evidenced especially in the exciton absorption region. Due to overlap of the 3.61 eV emission band of Pb2+ centres with the 3.6 eV absorption band of Ce3+ centres, an effective nonradiative energy transfer from Pb2+ ions to Ce3+ ions takes place, resulting in the appearance of slower component in the luminescence decay kinetics of Ce3+ centres and decrease of the Ce3+-related luminescence intensity. 相似文献
18.
19.
Lubov' V. Snegur Yury S. Nekrasov Nataliya S. Sergeeva Zhanna V. Zhilina Vera V Gumenyuk Zoya A. Starikova Alexander A. Simenel Nataliya B. Morozova Irina K. Sviridova Valery N. Babin 《应用有机金属化学》2008,22(2):139-147
The toxicity of ferrocenylethyl benzotriazole ( 1 ) and other ferrocene compounds including ferrocenylmethyl benzimidazoles ( 4,5,6,11 ), ferricenium salts ( 3,9,10 ) and ferrocenylmethyl adenine ( 7 ), was studied. All ferrocene complexes under investigation showed low or medium toxicities. On the basis of an earlier model of chemical carcinogenesis, the antitumor activity of ferrocenylalkyl azoles 1, 8 and ferricenium salts 9, 10 was studied in vivo in the so‐called sub‐capsular test on human tumors. This effectiveness was compared with that of cisplatin. A series of ferrocenylalkyl azoles were synthesized by interacting azoles either with α‐hydroxyalkyl ferrocenes FcC(OH)R1R2 in organic solvent in the presence of aqueous HBF4 in quantitative yields or with trimethyl(aminomethyl)ferrocene iodide in an aqueous‐basic medium in good yields. The X‐ray determinations of molecular and crystal structures of α‐(1‐benzotriazolyl)ethylferrocene ( 1 ) and α‐(1‐naphthatriazolyl)ethylferrocene ( 12 ) were performed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
20.
In the present paper, we analyze an algorithm for solving problems of elastic and elastoplastic contact between rigid deformable
bodies taking into account the presence of additional media with various properties in the contact region. These may be nonlinear
properties of surface rough layers and films. To take into account the influence of such layers, the finite-element scheme
uses contact finite elements with nonlinear properties. We describe an algorithm developed for solving problems with various
types of nonlinearities. Using the example of experimental studies described in detail in [1, 2], we identify the nonlinear
properties of contact finite elements. Several examples are used to demonstrate the algorithm operating capability. 相似文献