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251.
C. Feiler M. Buser E. Kajari W. P. Schleich E. M. Rasel R. F. O’Connell 《Space Science Reviews》2009,148(1-4):123-147
In the present paper we follow three major themes: (i) concepts of rotation in general relativity, (ii) effects induced by these generalized rotations, and (iii) their measurement using interferometry. Our journey takes us from the Foucault pendulum via the Sagnac interferometer to manifestations of gravito-magnetism in double binary pulsars and in Gödel’s Universe. Throughout our article we emphasize the emerging role of matter wave interferometry based on cold atoms or Bose–Einstein condensates leading to superior inertial sensors. In particular, we advertise recent activities directed towards the operation of a coherent matter wave interferometer in an extended free fall. 相似文献
252.
S. Kobayashi N. Hasebe E. Shibamura O. Okudaira M. Kobayashi N. Yamashita Y. Karouji M. Hareyama K. Hayatsu C. d’Uston S. Maurice O. Gasnault O. Forni B. Diez R. C. Reedy K. J. Kim 《Space Science Reviews》2010,154(1-4):193-218
The Kaguya gamma-ray spectrometer (KGRS) has great potential to precisely determine the absolute abundances of natural radioactive elements K, Th and U on the lunar surface because of its excellent spectroscopic performance. In order to achieve the best performance of the KGRS, it is important to know the spatial response function (SRF) that describes the directional sensitivity of the KGRS. The SRF is derived by a series of Monte Carlo simulations of gamma-ray transport in the sensor of the KGRS using the full-fledged simulation model of the KGRS, and is studied in detail. In this paper, the method for deriving absolute abundance of natural radioactive elements based on the SRF is described for the analysis of KGRS data, which is also applicable to any gamma-ray remote sensings. In the preliminary analysis of KGRS data, we determined the absolute abundances of K and Th on the lunar surface without using any previous knowledge of chemical information gained from Apollo samples, lunar meteorites and/or previous lunar remote sensings. The results are compared with the previous measurements and the difference and the correspondence are discussed. Future detailed analysis of KGRS data will provide new and more precise maps of K, Th and U on the lunar surface. 相似文献
253.
In this paper, we present the results of the experimental studies of the average heat transfer value in a hemispherical recess
placed in the first, third, and fifth rows of the recess array when varying the frequency of the imposed air velocity fluctuations
in the channel. The range of the Reynolds and Strouhal number variations corresponded to operating conditions of the turbine
blade cooling systems. 相似文献
254.
The results of studying the average and local heat transfer on the surface of hemispherical protrusions arranged on one side
of the flat channel are presented. The experiments were carried out at the turbulent flow regime in varying the density of
protrusions arrangement and the channel height. 相似文献
255.
M. V. Klimenko V. V. Klimenko Yu. N. Koren’kov F. S. Bessarab I. V. Karpov K. G. Ratovsky M. A. Chernigovskaya 《Cosmic Research》2013,51(1):54-63
A study of the response of the thermosphere and ionosphere to sudden stratospheric warmings (SSWs) which occurred in January of 2008 and 2009 is presented. The Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) developed in the West Department of IZMIRAN was a theoretical basis for this study. A comparison of the simulation results of the thermosphere-ionosphere response to SSW events with the observational data over Irkutsk and also with theoretical and experimental studies carried out during the recent years is performed. SSW events were modeled by setting disturbances in the neutral temperature and density at the lower boundary of the GSM TIP model (80 km above the Earth’s surface). It is shown that the disturbances related to SSW lead to substantial global effects in the thermosphere and ionosphere. The analysis of the experimental data showed that, in spite of very similar solar and geophysical conditions on the background of which two considered stratospheric warming events happened, the occurring disturbances in temperature at heights of the mesosphere and lower thermosphere differ substantially from each other, although some common regularities still take place especially at heights of the ionospheric F region. 相似文献
256.
257.
Results of two-year (August 1995–July 1997) continuous observations of the auroral kilometric radiation (AKR) in the AKR-X experiment on board the high-apogee Interball-1 satellite are presented. Observations were carried out in the minimum of solar activity in a frequency range of 100–1500 kHz. The most effective detections of AKR occurred near the maximum of its spectrum at a frequency of 252 kHz and also at a frequency of 500 kHz. The data obtained made it possible to study in more detail the character of AKR global directivity, its frequency dependence, and some other parameters of the emission. These data are interpreted qualitatively in the context of the emission mechanism caused by cyclotron maser instability. 相似文献
258.
The results of studying a dispersed airflow around a single porous cylinder are presented. The flow field of carrying medium outside the cylinder is described within the framework of the Navier-Stokes equations for incompressible gas; inside the porous cylinder the Darcy-Brinkman extended equations for averaged velocity are used. The numerical solution of the medium equations is achieved in the FLUENT package. In the found field of carrying medium velocities the suspended particle trajectories are calculated. Also given are the dependences of the particle inertial deposition effectiveness on the Stokes number at various values of the Darcy number. 相似文献
259.
Calorimeters play an important role in cosmic-ray physics and, in particular, in experiments, which are carried out in the
atmosphere with balloons and on satellites in space. This paper presents a method of energy measurement for protons (at energy
higher than 20 GeV) with the help of a thin discrete calorimeter (using as an example the position-sensitive silicon-tungsten
calorimeter of the PAMELA experiment) developed based on the data of simulation by the Monte-Carlo method and on the results
of test experiment at an accelerator in charged particle beams. The method is based on measurement of the total released energy
and on the criterion of event selection, which characterizes the beginning of particle cascade development in the calorimeter.
The influence of insertion of additional parameters on the energy resolution obtained with the help of this method is also
studied. 相似文献
260.
S. G. Parafes’ 《Russian Aeronautics (Iz VUZ)》2010,53(2):126-133
An approach to the solution of a number of practical important problems of flight vehicle thin-walled structure design based
on a unified mathematical identification technique is proposed. These problems include estimation of functional performance
of existing structures, development of unconventional promising structures, structure design by a prototype and some others.
The original mathematical identification technique contains an identification criterion, identification procedures and methods
for formation of structure standards. 相似文献