共查询到20条相似文献,搜索用时 31 毫秒
1.
R. A. Bortnikov 《Russian Aeronautics (Iz VUZ)》2009,52(2):245-249
Alignment charts that make it possible to select a standard size of inert heatexchanger structures with specified output characteristics and a developed scheme of the low-temperature aerosol generator are presented. 相似文献
2.
Detection and attribution of climate change, and understanding solar influence on climate 总被引:1,自引:0,他引:1
W. J. Ingram 《Space Science Reviews》2006,125(1-4):199-211
The detection of externally-forced climate change in observations, and its attribution to specific forcings, sounds simple enough to some people, but with others it has a reputation as a complex and arcane specialism. In fact, both these impressions have some truth - in principle it is no more than regressing expected patterns of climate change (normally obtained from GCM sim-ulations forced with observed or reconstructed past forcings) against the corresponding observa-tions, with uncertainty estimates that try to be as rigorous as possible, but there are many technical complexities. This survey begins with some motivating examples, and then summarizes the principles, problems and procedure without formal mathematics, before surveying results with an emphasis on possible solar effects, and why they are particularly problematic. 相似文献
3.
Theory of electric field measurements conducted in the magnetosphere with electric probes 总被引:1,自引:0,他引:1
U. Fahleson 《Space Science Reviews》1967,7(2-3):238-262
Conclusions From the preceding discussion of possible errors and from the probe dimensions given in Tables IV and V the conclusion can be drawn that there should be no great difficulties in making rough (10–20%) measurements of electric fields in the ionosphere. With moderate efforts (using metallized balloons) it should also be possible to obtain order of magnitude estimates of electric fields out to a distance of several earth radii.With large efforts it seems possible also in the future to measure electric fields along the magnetic field lines, but at present indirect methods may be more attractive. 相似文献
4.
郭威 《沈阳航空工业学院学报》2003,20(1):84-86,44
知识经济时代企业的发展主要依靠其所拥有和控制的人力资源,而其中的人才资源是经济发展的最主要资源。企业通过对人才的合理配置及适时激励,使人才资源最大程度地发挥作用,为企业创造更多的财富。 相似文献
5.
A. V. Borisoglebskii 《Russian Aeronautics (Iz VUZ)》2007,50(2):172-177
A method of numerical simulation of nonstationary gasodynamic processes in a pulsejet engine is proposed. The method makes it possible to provide a rather high precision for computational grids both with small and large cells. The calculation results showed a good agreement with the experimental data. 相似文献
6.
State Estimation for Discrete Systems with Switching Parameters 总被引:1,自引:0,他引:1
The problem of state estimation for discrete systems with parameters which may be switching within a finite set of values is considered. In the general case it is shown that the optimal estimator requires a bank of elemental estimators with its number growing exponentially with time. For the Markov parameter case, it is found that the optimal estimator requires only N2 elemental estimators where N is the number of possible parameter values. 相似文献
7.
《Air & Space Europe》1999,1(2):26-28
Extensive contacts with our international partners have made it possible to narrow down our options considerably. 相似文献
8.
In this paper, a process of flanging to create thin-walled axisymmetrical shells with the shape of truncated cone is analyzed. Also presented are some dependences that make it possible to determine the relative depth of a formed piece at the given piece-blank thickness ratio. 相似文献
9.
I. E. Lobanov 《Russian Aeronautics (Iz VUZ)》2010,53(3):353-357
The analytical solution of a nonlinear nonstationary inverse problem of heat conduction for a bodies with low heat conduction
coefficients of one-dimensional geometry is presented. The solutions obtained make it possible to restore the boundary conditions
rather exactly using the results of heat flux measurements. 相似文献
10.
《Air & Space Europe》2000,2(5):80-83
In the framework of the research project TUBSAT-N (Technical University of Berlin SATellite-Nano) it has been demonstrated that it is possible to achieve ultra low cost space access very quickly. TUBSAT-N and TUBSAT-N1 were launched as a satellite cluster in July 1998 with a convertible Russian military SS-23 SHTIL Rocket from a submarine. This project should prove that nanosatellite technology can be a good solution for a commercial ultra-low cost project. 相似文献
11.
C. W. Allen 《Space Science Reviews》1965,4(1):91-122
This paper reviews (a) the earth's ionosphere, and (b) the solar atmosphere, in relation to the recent observations of solar XUV. The expected ionospheric characteristics are derived as directly as possible from the XUV observations and then compared with the well-known D-, E-, and F-layer formations. The comparison leads to (1) a high ionospheric recombination coefficient decreasing rapidly with height, (2) contributions to the E-layer from both UV and X-rays, and (3) very little difference in the solar cycle variations from the D-, E-, and F-layers although intensity variations are greater from high than low ions. The flux measurements of the identified XUV solar emission lines give information on the numbers of ions in the solar atmosphere. This makes it possible to derive (1) the amount of solar material in each temperature range, (2) the chemical abundances, and (3) the physical differences between quiet solar atmosphere, centres of activity, and flares. When the new dielectronic recombination coefficients are well investigated it should be possible to redetermine the distribution of solar material with temperature. The fitting of such results to chromospheric and coronal models provides many problems. 相似文献
12.
使用Flash软件制作机构动态演示计算机辅助教学课件 ,并能够通过按钮指令控制机构运动。说明了如何将其插入到软件FrontPage中在网上发布 ,利用此方法 ,可以制作多种网上发布的课件。 相似文献
13.
A. V. Sedel’nikov 《Russian Aeronautics (Iz VUZ)》2007,50(3):322-325
Making use of the Weierstrass-Mandelbrot fractal function, some problems connected with the adequate assessment of microaccelerations aboard a spacecraft are considered. The ranges of values for the function parameters that make it possible to simulate the quasi-static component of microaccelerations are also determined. 相似文献
14.
采用近年发展起来的随机选取法,研究非均匀二维超音来流流过6种不同形状的楔型压缩面时的波后非均匀超音流场。结果表明来流的非均匀性对下游流场具有重大影响,对6种不同形状楔型压缩面流场的计算表明,单纯用改变压缩面型面的办法难以减少来流的非均匀性,但是可以部分改善下游流场的非均匀程度,在研究的6种型面中,凹圆弧压缩面及等熵压缩面在本文限定的非均匀来流下,其性能优于其它4种型面的压缩面。 相似文献
15.
16.
V. T. Grumondz M. A. Polishchuk S. S. Chertoryzhskaya A. S. Krivoguz 《Russian Aeronautics (Iz VUZ)》2012,55(3):251-258
In this paper, we consider a problem of synthesizing the control system of a small gliding (unpowered) aerial vehicle (GAV) with a high-aspect ratio wing (?? ?? 10). This wing makes it possible to increase significantly the flight range and improve the maneuvering characteristics of the aerial vehicle itself. 相似文献
17.
V. F. Pavlov V. A. Kirpichev N. I. Yakovenko D. V. Ivanov 《Russian Aeronautics (Iz VUZ)》2007,50(4):442-445
Residual stresses and endurance strength of specimens with stress concentrators are considered. The results obtained make it possible to predict the fatigue limit of strengthened parts with concentrators in the case of tension-compression. 相似文献
18.
B. I. Mamaev 《Russian Aeronautics (Iz VUZ)》2009,52(1):72-76
Based on the results of the gas temperature measurements in the turbine flow passage of a number of full-scale GTEs and GTPs, we obtained the magnitudes of coefficients that make it possible to refine with respect to radius the temperature profile at the blading inlet in the gasodynamic calculations. 相似文献
19.
We consider the problem of separating and estimating the waveform of superimposed signals received by an array of sensors. If the array is well calibrated it is possible to first estimate the directions of arrival (DOA) of the signals and then use this information to separate the signals. When the array is not calibrated, but the array elements have the same unknown gain pattern, up to an unknown multiplicative factor and the phases of the elements are arbitrary and unknown, it is possible to estimate the array steering vectors and then use this information for signal estimation. We compare the quality of the estimated signals in the calibrated case with the quality of the estimated signals in the uncalibrated case, in terms of the output signal-to-interference ratio (SIRO) and output signal-to-noise ratio (SNRO). 相似文献
20.
《Aerospace Science and Technology》1999,3(3):141-151
This paper presents a control design approach based on eigenstructure assignment by dynamic feedback. The proposed method permits the designer to handle simultaneously robustness against real parameter variations (from a multimodel point of view) and the use of structured gain including, as a special case, scheduled gains. Furthermore, given a feedback gain, it is possible to re-design it by eigenstructure assignment by re-assigning its leading eigenstructure. This technique has two advantages. First, it can be viewed as an efficient controller order reduction, second, the design methodology can be initialized, for example, by H∞- or μ-synthesis which makes it possible to combine the advantages of techniques of different natures. The proposed method alternates multimodel design and μ-analysis but apart from these natural iterations, only algebraic computation is involved. 相似文献