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71.
Noncollinear difference frequency mixing of dye laser and Nd:YAG second harmonic (fundamental) radiation from a commercial
laser system is employed for the generation of 2.7–5.3 μm (1.6–1.7 μm) radiations in a flux-grown KTiOAsO1 crystal. The generated radiation is used to scan the methane absorption in the fundamental (v
3) and its first overtone (2v
3) band at pressure 90 torr in a laboratory made single pass gas cell of length 33 cm. 相似文献
72.
Several surfactant molecules self-assemble in solution to form long, cylindrical, flexible wormlike micelles. These micelles
can be entangled with each other leading to viscoelastic phases. The rheological properties of such phases are very interesting
and have been the subject of a large number of experimental and theoretical studies in recent years. We shall report our recent
work on the macrorheology, microrheology and nonlinear flow behaviour of dilute aqueous solutions of a surfactant CTAT (Cetyltrimethylammonium
Tosilate). This system forms elongated micelles and exhibits strong viscoelasticity at low concentrations (∼0.9 wt%) without
the addition of electrolytes. Microrheology measurements of G(θ) have been done using diffusing wave spectroscopy which will be compared with the conventional frequency sweep measurements
done using a cone and plate rheometer. The second part of the paper deals with the nonlinear rheology where the measured shear
stress σ is a nonmonotonic function of the shear rate
. In stress-controlled experiments, the shear stress shows a plateau for
larger than some critical strain rate, similar to the earlier reports on CPyCl/NaSal system. Cates et al have proposed that the plateau is a signature of mechanical instability in the form of shear bands. We have carried out extensive
experiments under controlled strain rate conditions, to study the time-dependence of shear stress. The measured time series
of shear stress has been analysed in terms of correlation integral and Lyapunov exponent to show unambiguously that the behaviour
is typical of low dimensional dynamical systems. 相似文献
73.
74.
Ashok Kumar Ashoke Chandra Deb S. K. Mukerjee V. N. Vaidya D. D. Sood 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):375-377
Solvent extraction of plutonium(VI) from nitric acid (1 to 5M) into 20% and 30% TBP in dodecane saturated with uranium(VI)
(0% to 80%) has been studied. For a particular nitric acid concentration, the distribution coefficient (K
d
) is found to decrease with the increase in saturation of organic phase with uranium(VI). At a fixed organic phase the saturationK
d
increased with increase in nitric acid concentration, however, the magnitude of this increase inK
d
decreased with the increase in saturation. 相似文献
75.
§ 1.Introduction WearegivenkindependentWishartdensitiesofthe (p +q)× (p +q)randomsymmetricpositivedefinitematricesG1,… ,Gktobeg(Gi) =Kexp -12 trR- 1i Gi Gi12 (ni- q-p- 1) ,(1 )wherei=1 ,… ,k,andRidenotesthepopulationcorrelationmatrixofthei thpopulationandKasagenericletterdenote… 相似文献
76.
Structures of complexes formed in aqueous solutions by some anionic polyelectrolytes (double and single stranded (ds and ss)
DNA, poly(vinyl sulfonate) (PVS), and poly(styrene sulfonate) (PSS)) with a cationic surfactant system consisting of cetyltrimethylammonium
bromide (CTAB) and sodium 3-hydroxy-2-naphthoate (SHN) have been determined using small angle X-ray diffraction. All complexes
are found to have a two-dimensional (2-D) hexagonal structure at low SHN concentrations. Analysis of the diffraction data
shows that the ds DNA—CTAB complex has an intercalated structure, with each DNA strand surrounded by three cylindrical micelles.
On increasing SHN concentration, DNA—CTAB—SHN complexes exhibit a hexagonal-to-lamellar transition, whereas PVS complexes
show a hexagonal → centered rectangular → lamellar transition. PSS complexes show yet another sequence of structures. These
results indicate the significant influence of the chemical nature of the polyelectrolyte on the structure of the complexes. 相似文献
77.
Motivated by recent observations of rheochaos in sheared wormlike micelles, we study the coupled nonlinear partial differential equations for the hydrodynamic velocity and order-parameter fields in a sheared nematogenic fluid. In a suitable parameter range, we find irregular, dynamic shear banding and establish by decisive numerical tests that the chaos we observe in the model is spatiotemporal in nature. 相似文献
78.
79.
P. C. Sood 《Zeitschrift für Physik A Hadrons and Nuclei》1983,310(1-2):95-97
The band-head energies of the two-quasiparticle states expected in the doubly odd deformed nucleus170Ho are calculated for a zero range residual interaction. The results are compared with the available experimental information. It is concluded that the ground state has the Nilsson configuration 6+{7/2?[523↑] p }+5/2[512↑] n being the 2.76m isomer whereas the 43s isomer is the 1+ ∑=0 state arising from the same configuration and lies at about 100 keV excitation energy in agreement with the experiment. The first excited state in this nucleus is predicted to be the 4?{3/2+[411↑] p +5/2?[521↑] n } state close to the ground state with the corresponding 1? ∑=0 member expected to appear well above the 1+ isomer. 相似文献
80.
A generalized VMD mechanism, implemented through the OPC model, is proposed for E1 and M1 decays of mesons wherein the photon couples to two infinite sequences of radial excitations of 3S1 and 3D1 states. The results reveal good accord with data under the conventional assignments, with a parameter signifying a reduced magnetic coupling of ψ-ions with c quarks. 相似文献