RPC-MAG The Fluxgate Magnetometer in the ROSETTA Plasma Consortium

The fluxgate magnetometer experiment onboard the ROSETTA spacecraft aims to measure the magnetic field in the interaction region of the solar wind plasma with comet 67P/Churyumov-Gerasimenko. It consists of a system of two ultra light (about 28 g each ) triaxial fluxgate magnetometer sensors, mounted on the 1.5 m long spacecraft boom. The measurement range of each sensor is ±16384 nT with quantization steps of 31 pT. The magnetometer sensors are operated with a time resolution of up to 0.05 s, corresponding to a bandwidth of 0–10 Hz. This performance of the RPC-MAG sensors allows detailed analyses of magnetic field variations in the cometary environment. RPC-MAG furthermore is designed to study possible remnant magnetic fields of the nucleus, measurements which will be done in close cooperation with the ROSETTA lander magnetometer experiment ROMAP.     

在二元柔壁自适应风洞中利用面元法进行三元模型实验

简要叙述了在西北工业大学二元柔壁自适应风洞中利用面元法进行二元半机翼模型试验的研究情况，分析了面元法的基本思想和部分试验结果。     

Spectroscopic Measurement of Coronal Compositions

Although the elemental composition in all parts of the solar photosphere appears to be the same this is clearly not the case with the solar upper atmosphere (SUA). Spectroscopic studies show that in the corona elemental composition along solar equatorial regions is usually different from polar regions; composition in quiet Sun regions is often different from coronal hole and active region compositions and the transition region composition is frequently different from the coronal composition along the same line of sight. In the following two issues are discussed. The first involves abundance ratios between the high-FIP O and Ne and the low-FIP Mg and Fe that are important for meaningful comparisons between photospheric and SUA compositions and the second involves a review of composition and time variability of SUA plasmas at heights of 1.0≤h≤1.5R _⊙.     

What Determines the Composition of SEPs in Gradual Events?

Gradual solar energetic particle (SEP) events are evidently accelerated by coronal/interplanetary shocks driven by coronal mass ejections. This talk addresses the different factors which determine the composition of the accelerated ions. The first factor is the set of available seed populations including the solar wind core and suprathermal tail, remnant impulsive events from preceding solar flares, and remnant gradual events. The second factor is the fractionation of the seed ions by the injection process, that is, what fraction of the ions are extracted by the shock to participate in diffusive shock acceleration. Injection is a controversial topic since it depends on the detailed electromagnetic structure of the shock transition and the transport of ions in these structured fields, both of which are not well understood or determined theoretically. The third factor is fractionation during the acceleration process, due to the dependence of ion transport in the turbulent electromagnetic fields adjacent to the shock on the mass/charge ratio. Of crucial importance in the last two factors is the magnetic obliquity of the shock. The form of the proton-excited hydromagnetic wave spectrum is also important. Finally, more subtle effects on ion composition arise from the superposition of ion contributions over the time history of the shock along the observer’s magnetic flux tube, and the sequence of flux tubes sampled by the observer.     

Relationship between daily variation of cosmogenic nuclide Be-7 concentration in atmosphere and solar activities

Daily Be-7 concentrations in air at the height of 15 m are continuously observed at 38°15.2′N, 140°20.9′E, between 2000 and 2001. The average concentration and the relative standard deviation were 4.0 mBq/m³ and 50% in 2000–2001, respectively. The Be-7 concentrations increased 2.5% with the decrease in the sunspot numbers by 6.7% for the term of two years. From the power spectral analysis, the periodicity of 26 days is shown for the daily Be-7 concentrations. The folding analysis indicates that the time variation of the Be-7 concentration is similar to that of the ground-based neutron counting rate, and the phase delay for the minimum portion of Be-7 concentration was roughly 8 days to the maximum sunspot number. These results indicate that the Be-7 concentrations in the air at ground level have 26 day periodicity as a component of time variations and the time variation is caused by the solar modulation of galactic cosmic rays, which corresponds to the variation of the sunspot number due to the rotation of the sun.     

0.1米低温风洞的设计

本文阐述了我国首次设计和建造的低温风洞的设计特点及共性能。这是一座以风扇驱动的闭口回流式风洞,用氮气作试验气体。试验段为0.1米的方形截面。计运转参数范围为:M=0.04～0.40,P_t=101.2 kPa～202.6kPa,T_t=79K～320K。试验时间为半小时。风洞壳体是用铝合金制造的,外部用超细玻璃棉绝热。风扇用交流电机拖动,转速用变频控制。     

八十年代风工程

本文扼要地回顾了推动风工程发展成为一门新兴独立学科以来的重大事件,并介绍了八十年代在该学科领域内取得的主要进展和研究动向。     

国外风洞试验的新机制、新概念、新技术

风洞是空气动力学研究的重要地面试验设备,是保证一个国家航空航天处于领先地位的基础研究设施。面对新世纪航空航天领域的激烈竞争,世界发达国家加强了新概念风洞研制,改革风洞运行机制,一些新技术也在大型生产性风洞得到应用。     

螺旋桨滑流对飞机绕流影响的试验研究

在国产双涡桨支线飞机发展过程中，曾专门研究过螺旋桨滑流对飞机表面压力分布的影响。本文以此为基础，从滑流对飞机绕流影响出发，研究了螺旋桨滑流引起飞机气动特性的变化，重点讨论了气动特性变化的机理。     

摩托车空气动力学研究进展

世界摩托车工业已得到很大的发展。随着近几年来中国摩托车产量的迅速上升,加速摩托车的研究是目前摩托车发展的一种趋势。这种研究无论是对提高产品的性能,还是节能降耗部具有重要的意义。摩托车的气动特性是其设计的重要依据。目前德国,日本等国已经利用道路试验、风洞模拟进行这种研究,并促进了产品的开发,但国内的这种研究还有待进一步完善。