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141.
以直升机尾斜轴为研究对象,推导了传动轴的分布质量传递矩阵,模型中考虑了弯矩、横向位移、剪切变形、转动惯量、陀螺力矩和轴向力等
因素的综合影响。建立了膜片联轴器和弹性支承的传递矩阵。给出了尾传动轴系临界转速的计算方法。以三支点水平轴系为分析对象,将本文传递矩阵法计算的结果与有限元法计算的结果进行了对比分析,以检验本文传递矩阵法的有效性。本文传递矩阵法相对于有限元法的最大计算误差为4.1%,表明本文传递矩阵法的计算精度较高,同时本文传递矩阵法的计算速
度更快,便于设计人员进行尾传动轴系临界转速的影响因素分析。 相似文献
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145.
G. De Franceschi A. De Santis S. Pau 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(12):61-64
The method of Spherical Cap Harmonic Analysis (SCHA) /1/ has been applied /2/ to the critical frequency of the F2 layer (f0F2) for mapping and modelling it over Europe. The model was based on longitudinal expansion in Fourier series, and fractional Legendre colatitudinal functions over a spherical cap including Europe. Here a new and simpler technique, previously developed for the regional modelling of the geomagnetic field /3/, is introduced and described. The basic improvement of the new method, called Adjusted Spherical Harmonic Analysis (ASHA), implies the use of conventional Spherical Harmonic (SH) functions after the colatitude interval is adjusted to that of a hemisphere. Examples are shown dealing with the application of ASHA to retrospective mapping and modelling of the monthly medians of f0F2 over Europe. 相似文献
146.
本文介绍了设计符合现代标准的智能大厦时应考虑的一些问题,阐述了在进行智能化设计时如何进行方案分析、系统设计的方法。 相似文献
147.
De Gaudenzi R. Lijphart E.E. Vassallo E. 《IEEE transactions on aerospace and electronic systems》1993,29(1):27-43
The European Space Agency's (ESA) multipurpose satellite tracking system is introduced. The system is able to perform accurate satellite ranging and Doppler measurements for a variety of mission types, i.e., from near-Earth satellites to deep space probes. The ranging signal is analyzed and described in an analytical manner from which the limits of the system performance are derived. A model of the overall system is presented and a few simulation results obtained thereby are compared with measurements performed with the ESA's Giotto and Hipparcos scientific missions 相似文献
148.
W G Sannita M Acquaviva S L Ball F Belli S Bisti V Bidoli S Carozzo M Casolino F Cucinotta M P De Pascale L Di Fino S Di Marco R Maccarone C Martello J Miller L Narici N S Peachey P Picozza A Rinaldi D Ruggieri M Saturno D Schardt M Vazquez 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,33(8):1347-1351
ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define reliable experimental conditions for space research; and (3) to develop animal models to study the physiological consequences of space travels on humans. Remotely controlled mouse setup, applied electrophysiological recording methods, remote particle monitoring, and experimental procedures were developed and tested. The project has proved feasible under laboratory-controlled conditions comparable in important aspects to those of astronauts' exposure to particle in space. Experiments are performed at the Brookhaven National Laboratories [BNL] (Upton, NY, USA) and the Gesellschaft für Schwerionenforschung mbH [GSI]/Biophysik (Darmstadt, FRG) to identify possible electrophysiological changes and/or activation of protective mechanisms in response to pulsed radiation. Offline data analyses are in progress and observations are still anecdotal. Electrophysiological changes after pulsed radiation are within the limits of spontaneous variability under anesthesia, with only indirect evidence of possible retinal/cortical responses. Immunostaining showed changes (e.g. increased expression of FGF2 protein in the outer nuclear layer) suggesting a retinal stress reaction to high-energy particles of potential relevance in space. 相似文献
149.
Following our previously proposed technique, we have used the recent -ray observations of Mkr421 to place theoretically significant constraints on the magnitude of the intergalactic infrared radiation field (IIRF). Our 2 upper limits are consistent with normal IR production by stars and dust in galaxies. They rule out exotic mechanisms proposed to produce a larger IIRF. Although they are still subject to revision and are unconfirmed, the data on the spectrum of Mkr421 hint at a possible absorption cutoff which could be produced by an IIRF of the magnitude expected from stellar emission and reprocessing in galaxies. Using models for the low energy intergalactic photon spectrum from microwave to ultraviolet energies, we calculate the opacity of intergalactic space to -rays as a function of energy and redshift. These calculations indicate that the GeV -ray burst recently observed by the CGRO EGRET detector originates at a redshift less than 1.5. 相似文献
150.
UCAV任务规划系统的研究进展及发展趋势 总被引:7,自引:0,他引:7
分析了无人作战飞机任务规划系统的特点,按照规划范围和时段对无人作战飞机任务规划系统进行分层研究,讨论和分析了各个层次的作用及发展现状。最后,展望了无人作战飞机任务规划系统的发展趋势。 相似文献