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71.
B. V. Perepelitsa 《Thermophysics and Aeromechanics》2012,19(4):571-578
Results of experimental investigation of nonstationary temperature field in the flow and on the surface of the channel with corrugated wall are presented at a jump-like change of heat release in time. The changes were performed at the air flow in a rectangular channel, whose one heated wall was made as a plate with triangular corrugation oriented at 45° relative to the main flow direction. The microthermocouples with the thickness of below 10 microns were used to perform these changes. Investigations revealed typical regularities of temperature evolution in the flow and along the perimeter of the heated rib. Experimental data on time-temperature dependence are approximated well by the exponential function. 相似文献
72.
McIntire MJ Yamaguchi M Kol'chenko MA Vainer YG Chronister EL 《The journal of physical chemistry. B》2006,110(1):227-233
The effect of high pressure on the optical dephasing of chromophores in organic polymers at low temperature is evaluated within the stochastic sudden jump two-level-system (TLS) model. The approximations within the "standard" TLS model cannot account for the observed pressure dependence of the pure dephasing rate without ad hoc assumptions about changes in the TLS density of states. However, the photon echo model of Geva and Skinner for disordered systems can be used to model pressure-dependent optical dephasing results for a variety of doped polymer systems without assuming changes in the TLS density of states. The relative importance of pressure-induced changes in TLS density, chromophore-TLS coupling, and TLS-phonon coupling is evaluated by fitting experimental high-pressure photon echo results to the TLS model. 相似文献
73.
Santhi Ani Joseph Misha Hari Gaurav Sharma V.M. Hadiya V.P.N. Nampoori 《Optics Communications》2010,283(2):313-581
Dual beam mode-matched thermal lens method has been employed to measure the heat diffusion in nanofluid of silver with various volumes of rhodamine 6G, both dispersed in water. The important observation is an indication of temperature dependent diffusivity and that the overall heat diffusion is slower in the chemically prepared Ag sol compared to that of water. The experimental results can be explained assuming that Brownian motion is the main mechanism of heat transfer under the present experimental conditions. Light induced aggregation of the nanoparticles can also result in an anomalous diffusion behavior. 相似文献
74.
Mikhail Auguston Misha Koshelev Olga Kosheleva 《International Journal of Theoretical Physics》1998,37(11):2851-2856
There are many results that show that causalityis indeed the fundamental notion of physics. Inparticular, it is known that for pointwise events,causality implies the Lorentz group. In quantum fieldtheory, it is known that pointwise particles lead todivergences and therefore nonpoint particles arenecessary (e.g., strings). Since particles are nonpoint,events occurring to these particles are also nonpoint events. In this paper, we show that even if weconsider nonpoint events, causality still implies theLorentz group. In other words, even for nonpoint events,the notion of causality is still fundamental. 相似文献
75.
Misha Verbitsky 《Central European Journal of Mathematics》2011,9(3):535-557
Let M be a hyperkähler manifold, and F a reflexive sheaf on M. Assume that F (away from its singularities) admits a connection ? with a curvature Θ which is invariant under the standard SU(2)-action on 2-forms. If Θ is square-integrable, such sheaf is called hyperholomorphic. Hyperholomorphic sheaves were studied at great length in [21]. Such sheaves are stable and their singular sets are hyperkähler subvarieties in M. In the present paper, we study sheaves admitting a connection with SU(2)-invariant curvature which is not necessary L 2-integrable. We show that such sheaves are polystable. 相似文献
76.
An attosecond streak camera holds the promise of time resolving the dynamics of photoionization with a few-attosecond accuracy. But can the attosecond measurement be disentangled from the process it measures? We address this question by deriving simple closed-form analytical expressions for the measurement-related apparent time delays in photoionization, associated with the application of the attosecond streak camera and/or resolution of attosecond beating by interference of two-photon transitions techniques. Our analytical results are accurate on about the 1 asec level and show that both intrinsic and measurement-induced delays depend on the same scattering phase and are, therefore, not independent. We also suggest a procedure for extracting intrinsic time delays from the measurement and a possible resolution of the controversy caused by the experiments of Schultze et al. [Science 328, 1658 (2010)]. 相似文献
77.
Misha Gromov 《Central European Journal of Mathematics》2012,10(2):371-400
We introduce a notion of Hilbertian n-volume in metric spaces with Besicovitch-type inequalities built-in into the definitions. The present Part 1 of the article is,
for the most part, dedicated to the reformulation of known results in our terms with proofs being reduced to (almost) pure
tautologies. If there is any novelty in the paper, this is in forging certain terminology which, ultimately, may turn useful
in an Alexandrov kind of approach to singular spaces with positive scalar curvature [Gromov M., Plateau-hedra, Scalar Curvature
and Dirac Billiards, in preparation]. 相似文献
78.
Misha Verbitsky 《Mathematische Zeitschrift》2010,264(4):939-957
Let (M, ω) be a Kähler manifold. An integrable function ${\varphi}Let (M, ω) be a K?hler manifold. An integrable function j{\varphi} on M is called ω
q
-plurisubharmonic if the current ddcjùwq-1{dd^c\varphi\wedge \omega^{q-1}} is positive. We prove that j{\varphi} is ω
q
-plurisubharmonic if and only if j{\varphi} is subharmonic on all q-dimensional complex subvarieties. We prove that a ω
q
-plurisubharmonic function is q-convex, and admits a local approximation by smooth, ω
q
-plurisubharmonic functions. For any closed subvariety Z ì M{Z\subset M} ,
dim\mathbbC Z £ q-1{\dim_\mathbb{C} Z\leq q-1} , there exists a strictly ω
q
-plurisubharmonic function in a neighbourhood of Z (this result is known for q-convex functions). This theorem is used to give a new proof of Sibony’s lemma on integrability of positive closed (p, p)-forms which are integrable outside of a complex subvariety of codimension ≥ p + 1. 相似文献
79.
Mikhail Perepelitsa 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2010,114(1):267-276
We consider the Navier–Stokes equations for the motion of a compressible, viscous, pressureless fluid in the domain
W = \mathbbR3+{\Omega = \mathbb{R}^3_+} with the no-slip boundary conditions. We construct a global in time, regular weak solution, provided that initial density
ρ
0 is bounded and the magnitude of the initial velocity u
0 is suitably restricted in the norm ||?{r0(·)}u0(·)||L2(W) + ||?u0(·)||L2(W){\|\sqrt{\rho_0(\cdot)}{\bf u}_0(\cdot)\|_{L^2(\Omega)} + \|\nabla{\bf u}_0(\cdot)\|_{L^2(\Omega)}}. 相似文献
80.
O. V. Ovchinnikov M. S. Smirnov T. S. Kondratenko A. S. Perepelitsa I. G. Grevtseva S. V. Aslanov 《Optics and Spectroscopy》2018,125(1):107-112
Luminescence studies of singlet-oxygen photosensitization by methylene blue molecules in various solvents, as well as by hybrid associates of this dye with colloidal Ag2S quantum dots with average sizes of 2.0, 2.4, and 2.7 nm, are performed. The conditions for simultaneous singlet-oxygen photosensitization and detection of the IR luminescence of colloidal Ag2S quantum dots passivated by thioglycolic acid are determined. 相似文献