排序方式: 共有264条查询结果,搜索用时 15 毫秒
121.
This paper presents the regularities of effect of the input asymmetry of the velocity profile on the flow structure in a separated diffuser of the GTE annular combustion chamber. These regularities allow predicting the integral value of hydraulic resistance. We experimentally identified a kind of dependence between the hydraulic losses and Reynolds number in the case of asymmetric velocity profile in a prediffuser assessing the growth of pressure losses. Some updated dependencies are proposed that take into account the joint effect of the input parameters of the working fluid on the integral characteristics of its effectiveness. 相似文献
122.
V. A. Afanas’ev G. L. Degtyarev V. I. Kiselev A. S. Meshchanov 《Russian Aeronautics (Iz VUZ)》2017,60(1):50-56
We present the results of analytical research of flight dynamics for a flight vehicle that is controlled by the adjustable center of mass in the vertical symmetry plane. The roll oscillations, which appear perpendicular to the symmetry plane due to technological errors, are eliminated by means of control rocket engines, for which a control law is assigned. 相似文献
123.
124.
The paper considers the special features of estimating microaccelerations aboard the Foton-M no. 4 spacecraft, which are connected with the decision on cancelling the spacecraft injection from the reference orbit into the operating one. 相似文献
125.
K. J. Meech M. F. A’Hearn Y. R. Fernández C. M. Lisse H. A. Weaver N. Biver L. M. Woodney 《Space Science Reviews》2005,117(1-2):297-334
Prior to the selection of the comet 9P/Tempel 1 as the Deep Impact mission target, the comet was not well observed. From 1999 through the present there has been an intensive world-wide observing
campaign designed to obtain mission critical information about the target nucleus, including the nucleus size, albedo, rotation
rate, rotation state, phase function, and the development of the dust and gas coma. The specific observing schemes used to
obtain this information and the resources needed are presented here. The Deep Impact mission is unique in that part of the mission observations will rely on an Earth-based (ground and orbital) suite of complementary
observations of the comet just prior to impact and in the weeks following. While the impact should result in new cometary
activity, the actual physical outcome is uncertain, and the Earth-based observations must allow for a wide range of post-impact
phenomena. A world-wide coordinated effort for these observations is described. 相似文献
126.
A mathematical model of the dispersed-film two-phase flow with phase slip in the vertical cylindrical channel is described. 相似文献
127.
Donald L. Hampton James W. Baer Martin A. Huisjen Chris C. Varner Alan Delamere Dennis D. Wellnitz Michael F. A’Hearn Kenneth P. Klaasen 《Space Science Reviews》2005,117(1-2):43-93
A suite of three optical instruments has been developed to observe Comet 9P/Tempel 1, the impact of a dedicated impactor spacecraft,
and the resulting crater formation for the Deep Impact mission. The high-resolution instrument (HRI) consists of an f/35 telescope with 10.5 m focal length, and a combined filtered CCD camera and IR spectrometer. The medium-resolution instrument
(MRI) consists of an f/17.5 telescope with a 2.1 m focal length feeding a filtered CCD camera. The HRI and MRI are mounted on an instrument platform
on the flyby spacecraft, along with the spacecraft star trackers and inertial reference unit. The third instrument is a simple
unfiltered CCD camera with the same telescope as MRI, mounted within the impactor spacecraft. All three instruments use a
Fairchild split-frame-transfer CCD with 1,024× 1,024 active pixels. The IR spectrometer is a two-prism (CaF2 and ZnSe) imaging spectrometer imaged on a Rockwell HAWAII-1R HgCdTe MWIR array. The CCDs and IR FPA are read out and digitized
to 14 bits by a set of dedicated instrument electronics, one set per instrument. Each electronics box is controlled by a radiation-hard
TSC695F microprocessor. Software running on the microprocessor executes imaging commands from a sequence engine on the spacecraft.
Commands and telemetry are transmitted via a MIL-STD-1553 interface, while image data are transmitted to the spacecraft via a low-voltage differential signaling (LVDS) interface standard. The instruments are used as the science instruments and are
used for the optical navigation of both spacecraft. This paper presents an overview of the instrument suite designs, functionality,
calibration and operational considerations. 相似文献
128.
T. P. Borisevich G. N. Il’in A. N. Korzhavin N. G. Peterova N. A. Topchilo A. A. Shpitalnaya 《Cosmic Research》2004,42(6):561-570
We present the results of spectral and polarization observations of two large sunspot groups, NOAA 0484 and NOAA 0486 + 0488, which determine high solar activity in October–November 2003. The observations are made with the Large Pulkovo Radio Telescope (LPRT) in the range 2.7–20 cm, the one-dimensional (E-W) resolution of observations being 1–6 arc min, respectively. The main characteristics of the corona radio emission above these active regions are measured, allowing us to follow their dynamics during the entire period of their existence on the solar disk with a period of one day. The analysis of the obtained results is presented from the point of view of the well-known Tanaka-Enome criterion [1–2] (on the basis of this criterion one can predict strong flares from characteristics of radio emission of an active region in quasi-quiet state). Using the activity in October–November 2003 as an example, we demonstrate the capabilities of a new method for estimating the level of solar activity. It was developed on the basis of long-term observations of the Sun by LPRT [3].Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 585–594.Original Russian Text Copyright © 2004 by Borisevich, Ilin, Korzhavin, Peterova, Topchilo, Shpitalnaya. 相似文献
129.
Gillmann Cedric Way M. J. Avice Guillaume Breuer Doris Golabek Gregor J. Höning Dennis Krissansen-Totton Joshua Lammer Helmut O’Rourke Joseph G. Persson Moa Plesa Ana-Catalina Salvador Arnaud Scherf Manuel Zolotov Mikhail Y. 《Space Science Reviews》2022,218(7):1-21
Space Science Reviews - The BepiColombo Environment Radiation Monitor (BERM) on board the European Space Agency’s Mercury Planetary Orbiter (MPO), is designed to measure the radiation... 相似文献
130.
A study is made to define a procedure of cooperative processing of goniometric and range difference measurements in multilateral system of passive radiolocation. As a result, we worked out the computational algorithms, which implement this procedure. The accuracy characteristics are estimated. 相似文献