Proposal for a reference model of the middle atmosphere of the southern hemisphere

Available rocketsonde information has been used to compile tables of monthly mean temperature, pressure, density and zonal wind for the middle atmosphere of the southern hemisphere with the purpose of revising similar tables presented to COSPAR earlier. The altitude range is 25 to 80 km in steps of 5 km. The latitude range is 0° to 70°S with a 10° step. The compatability of different sets of temperature measurements is discussed. Mean values of temperature, pressure and zonal wind obtained for the southern hemisphere are compared with northern hemisphere model values. Large differences between the hemispheres (up to 20°C in temperature, 20–30% in pressure, 30–50 m/s in wind) imply that reference atmospheres such as CIRA should be complemented by southern hemisphere climatology.     

跨声速高雷诺数圆球绕流的实验研究

本文采用无支撑干扰、洞壁影响很小的带加压抽空系统的弹道靶设备,进行了雷诺数在10~5相似文献   

西北丝绸之路旅游区创新品牌研究

西北丝绸之路旅游区应共同携手,在五省区范围内打破区域限制,相互开放市场,携手打造旅游强势品牌和精品线路,增强品牌整体竞争实力,共同打造"丝绸之路"黄金旅游品牌.以丝绸之路品牌旅游区为核心,加强区域联合和区域协作,实现资源整合,提升陕、甘、宁、青、新地区旅游整体形象和影响力,联合打造西北丝绸之路旅游区旅游品牌和提升丝绸之路旅游品牌竞争力.     

Interaction of artificially injected plasma flows with ionospheric plasma

Results of rocket experiments on study of plasma flows (PF) artificially injected by sources separated from vehicles and their effect on medium parameters in ionosphere at altitudes 160:230 km are presented.PF were injected comprising lithium ions with velocities 1,2 x 10⁴ m/sec. and cesium-potassium ions with velocities (1,4–1,5)x10³ m/sec. Mass flow rate in case of lithium PS is 2 mg/sec, and in case of cesium-potassium PS is 0,2 g/sec. During experiments mass-spectrometer measurements of ion medium content in ranges of different ion masses were held, disturbancies of electric fields with frequencies up to 20 kHz and electron flows with energies 0,7keV, 4,6keV and over 40 keV were controlled at distancies from 150m to (500–600)m between plasma source and scientific equipment.     

A solar type U burst in the decimetric range

This paper analyzes a Type U burst at 1.0 – 2.8 GHz which occurred between 12:36:26 – 12:36:32 UT on 1992 August 22, observed by Ond ejov Observatory, Czech Republic. This may be the first example of Type U bursts in the decimetric range, as far as we know. From analysis we came to the following conclusion: (1) The frequency drift rates of the ascending and descending branches are 1.25 and 0.225 GHz/s, respectively, and the velocities of the electron beam are 0.38 c and 0.26 c, respectively; (2) The burst decay of the ascending branch is larger than that of the descending branch; (3) The variations of the maximum frequencies of instantaneous spectra with time appear as from the highest (1.92 GHz) to the lowest (1.0 GHz), then toward higher frequency (1.53 GHz) (this is consistent with that predicted by plasma emission theory); (4) The bandwidths of the ascending branch are about twice that of the descending branch (this may be caused by the larger drift rates of the ascending branch); (5) The temperature of the coronal loop apex is 6.3 × 10⁶ K; (6) The magnetic field at the top of the loop is greater than 9.2 G; (7) This U burst emission is plasma radiation at the second harmonic.     

Effects of prolonged exposure to space flight factors for 175 days on lettuce seeds

We have studied the effects of prolonged (up to 175 days) exposure of $\text{Lactuca sativa}$ seeds to space flight factors, including primary cosmic radiation heavy ions. The data obtained evidence a significant fourfold increase ofs pontaneous mutagenesis in seeds both with regard to the total number of aberrant cells as well as the formation of single cells with multiple aberrations. Comparison of the present experiment with earlier works shows that the frequency of such aberrations increases with the duration of the flight.     

Fluxes of Quasi-trapped Electrons with Energies >0.08 MeV in the Near-Earth Space on Drift Shells <Emphasis Type="Italic">L</Emphasis> < 2

We study the characteristics of fluxes of electrons with energy >80 keV in the near-Earth space regions corresponding to the drift shells L = 1.7, 1.4, and 1.1 observed during the entire period of the GRIF experiment onboard the Spectr module of the Mir orbital station from October 1995 to June 1997. The obtained geographic maps of the distribution of electron fluxes at the height of the station flight (400 km) and, also, the estimates of the spectra indicate that the South-Atlantic Anomaly provides for a mechanism of stable replenishment for shells with L < 1.5. The mechanism of stable replenishment of shells with L < 1.5 may be due to the scattering, in the residual atmosphere, of electrons from the inner radiation belt precipitating into the region of the South-Atlantic Anomaly.     

The waves observed in the ARAKS-East experiment

Experimental results of the Wave measurements over frequency range 0.1–5.0 MHz during the second launch of the ARAKS Experiment (15.02.75) are reported. The differences between the results of the first and the second launches are discussed.     

平板上钝缘舵在超声速绕流中的三维分离特性研究

对于平板上的直立钝缘舵在M_∞=1.79、2.04和2.50的条件下,研究了该平板干扰区中的三维分离特性。着重讨论了钝缘直径、舵面迎角和来流马赫数对主分离线位置和形状的影响。分析了该类三维分离在性态上更强地依赖于无粘流动特性。此外,还对分离区内的二次分离发展过程和形态进行了初步讨论。