排序方式: 共有76条查询结果,搜索用时 15 毫秒
1.
P. S. Timashev N. N. Vorobieva N. V. Minaev Yu. A. Piskun I. V. Vasilenko S. G. Lakeev S. V. Kostyuk V. V. Lunin V. N. Bagratashvili 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(8):1195-1200
A series of lactide and ε-caprolactone copolymers containing 4–24 mol % of ε-caprolactone with 20- to 30-kDa molecular weights are synthesized. Based on them, porous materials are produced by foaming in supercritical carbon dioxide. The pore size was shown to decrease with increasing ε-caprolactone content in copolymer, while the porosity of the entire sample was not altered. The resulting pore size also decreases if 7 wt % polyethylene glycol is added to the initial monomer mixture. The Young’s modulus of the porous samples decreases with increasing ε-caprolactone content and when polyethylene glycol is added. 相似文献
2.
V. N. Bagratashvili V. M. Gordienko E. I. Mareev N. V. Minaev A. V. Ragulskaya F. V. Potemkin 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(8):1211-1215
It is found that supercritical fluids are a unique source of multioctave supercontinuum radiation, which is generated upon filamentation of an intense femtosecond laser pulse. If the laser pulse power significantly exceeds the critical power of self-focusing, then a supercontinuum with a width of three and a half spectral octaves (from 350 to 2000 nm) is generated in supercritical xenon. The red wing of supercontinuum generated in supercritical carbon dioxide has the form of a plateau in the range from 1400 to 1900 nm, while the blue wing of the spectrum is almost completely attenuated. 相似文献
3.
V. N. Bagratashvili Yu. G. Vainer V. S. Doljikov S. F. Koliakov A. A. Makarov L. P. Malyavkin E. A. Ryabov E. G. Silkis V. D. Titov 《Applied Physics A: Materials Science & Processing》1980,22(1):101-105
The method of spectroscopy of spontaneous Raman scattering (RS) with time resolution has been applied for the first time to
diagnose the process of multiphoton ir molecular excitation (MPE). Some aspects of RS diagnostics of MPE processes are being
analyzed. It has been shown experimentally on SF6 and CF3I molecules that it is possible to study such important characteristics of excitation process as the fraction of molecules
involved in the process of excitation, vibrational energy distribution of molecules, stochastization of inner molecular energy. 相似文献
4.
5.
The degradation of the end surface of the delivery fiber due to the laser-induced hydrodynamic processes caused by the irradiation
of the water-saturated tissue by CW laser with a wavelength of 970 nm and moderate power (1–10 W) is analyzed. It is demonstrated
that the temperature in the vicinity of the end surface can be up to several thousand degrees at a laser intensity of about
104 W/cm2. Relatively high temperatures and pressures that are reached upon the collapse of the cavitation microbubbles lead to the
formation of the nanosized diamond-phase particles and supercritical water, which also facilitates the degradation of fiber. 相似文献
6.
A. A. Akovantseva N. A. Aksenova T. S. Zarkhina L. I. Krotova N. V. Minaev A. O. Rybaltovskii B. Ch. Kholkhoev I. A. Farion V. I. Yusupov V. F. Burdukovskii V. N. Bagratashvili P. S. Timashev 《Russian Journal of Applied Chemistry》2017,90(1):84-90
Rigid-chain heat resistant polymers (with poly-2,2'-p-oxydiphenylene-5,5′-bisbenzimidazole as example) were impregnated for the first time with a silver-containing precursor in formic acid and in supercritical carbon dioxide. A procedure allowing the precursor reduction to silver nanoparticles both throughout the volume by thermal annealing of the films in the temperature interval 100–150°С and in the targeted mode using lasers operating at 405 and 532 nm was developed. It opens prospects for developing a process for production of heatresistant optical gratings and light guides. The reduces nanoparticles and their agglomerates have the size in the interval 50–200 nm and give a plasmon band in the range 450–460 nm. 相似文献
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V. N. Bagratashvili A. F. Banishev S. A. Gnedoy V. I. Emelyanov A. N. Jerikhin K. S. Merzljakov V.Ya. Panchenko V. N. Seminogov 《Applied Physics A: Materials Science & Processing》1991,52(6):438-444
The formation of periodic ring structures during laser-induced chemical vapor deposition of metals from metal carbonyl is observed experimentally and described by a theoretical model. 相似文献
9.
V. N. Bagratashvili V. S. Doljikov V. S. Letokhov E. A. Ryabov 《Applied Physics A: Materials Science & Processing》1979,20(3):231-235
The selectivity dependence of multiphoton dissociation of CF3I on the conditions of excitation (pulse duration, concentration of the isotope under excitation and gas pressure) has been
studied. It has been shown that the main mechanism of selectivity loss isV-V exchange during a laser pulse. The elaborated model is in good agreement with the experiment. 相似文献
10.
V. N. Bagratashvili S. G. Dorofeev A. A. Ischenko V. V. Koltashev N. N. Kononov A. A. Krutikova A. O. Rybaltovskii G. V. Fetisov 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(7):1164-1170
With the use of supercritical carbon dioxide (SC-CO2), the matrix immobilization of photoluminescent silicon nanocrystals (nc-Si) in polytetrafluoroethylene microparticles (mp-PTFE)
is performed, which leads to the formation of mp-PTFE/nc-Si photoluminescent nanocomposite containing ∼103–104 nc-Si particles per mp-PTFE particle (1–2 μm in size). This approach is based on the effect of polymer swelling in SC-CO2, efficient SC-CO2-assisted transport of nanoparticles into the internal free volume of the polymer, and contraction of the nanocomposite after
the release of CO2, an effect that prevents the subsequent agglutination of nanoparticles. Particles of nc-Si photoluminescent in the visible
spectrum were synthesized from silicon suboxide powder (SiO
x
, x ≈ 1) heated at various temperatures within 25–950°C and then etched in concentrated hydrofluoric acid. The hydrosilylation
procedure was used to graft 1-octadecene molecules to the surface of nc-Si particles. As a result, the photoluminescence intensity
of nc-Si increased substantially. According to TEM images and small angle X-ray scattering data, the maximum size of nc-Si
particles did not exceed 5 nm and 7 nm, respectively, and the core of these nanoparticles consisted of crystalline silicon.
The structure and spectral properties of the initial nc-Si particles and synthesized mp-PTFE/nc-Si photoluminescent nanocomposite
microparticles were studied. 相似文献