Simultaneous investigation of magnetospheric plasma and spacecraft charging

The results of magnetospheric plasma fluxes measurement in geosynchronous orbit are presented. The measurements were done onboard the geosynchronous Russian “Electro” spacecraft (SC) in 1995–1997 years. The diurnal variations of the plasma density and temperature were observed at various levels of geomagnetic activity.     

The Effects of Transverse Magnetic Field and Density Variations on the Particle Energy Spectra in a Reconnecting 3D Current Sheet

Electron and proton acceleration by a super-Dreicer electric field is further investigated in a non-neutral reconnecting current sheet (RCS) with a variable plasma density. The tangential B _z and transverse magnetic field components B _x are assumed to vary with the distances x and z from the X nullpoint linearly and exponentially, respectively; the longitudinal component (a ‘guiding field’) is accepted constant. Particles are found to gain a bulk of their energy in a thin region close to the X nullpoint where the RCS density increases with z exponentially with the index λ and the tangential magnetic field B _x also increases with z exponentially with the index α. For the RCS with a constant density (λ = 0), the variations of the tangential magnetic field lead to particle power-law energy spectra with the spectral indices γ₁ being dependent on the exponent α as: for protons and for electrons in a strong guiding field (β > 10⁻²) and for electrons in a moderate or weak guiding field (β > 10⁻⁴). For the RCS with an exponential density increase in the vicinity of the X nullpoint (λ≥ 0) there is a further increase of the resulting spectral indices γ that depends on the density exponent index λ as for protons and for electrons in weaker guiding fields and as for electrons in stronger guiding fields. These dependencies can explain a wide variety (1.5–10) of particle spectral indices observed in solar flares by the variations of a magnetic field topology and physical conditions in a reconnecting region. This can be used as a diagnostic tool for the investigation of the RCS dynamics from the accelerated particle spectra found from hard X-ray and microwave emission.     

结构方程模型的预测建模方法

提出一种结构方程模型的动态预测建模方法,从而可以在无须未来样本数据的情况下,预测系统要素之间未来的因果关系。采用矩阵谱分解,将协方差矩阵唯一分解为特征值矩阵和特征向量矩阵乘积的形式.分别应用经典的线性回归方法和高维群点主轴旋转预测方法对特征值矩阵和特征向量矩阵建立预测模型,提出一种协方差矩阵的后推预测算法.采用极大似然法,迭代估计未来结构方程模型的各种参数.仿真实验例示了该方法的主要计算步骤.计算结果显示,利用本模型得到的拟合值精度较高,预测模型真实可信,表明这种方法可以用于分析和预测结构方程模型.      

航空母舰尾流数值仿真研究

为研究舰载飞机进舰着舰过程中航空母舰尾流的影响,选取了一个尾流模型在微机的MATLAB环境中模拟其速度的空间分布.根据成因将紊流分为4个组成部分:自由紊流分量的功率谱用成形滤波器法模拟,稳态分量通过线性插值得到,周期性分量可直接计算得到,而航母诱导的随机紊流分量则通过MATLAB的SIMULINK工具包模拟.模拟表明周期性分量占主导地位.此模型需要实验数据和船上实测数据进一步确认.     

Black hole accretion and X-ray spectra of QSOS

Changes in Eddington accretion ratios are thought to result in X-ray spectral index changes in Galactic binary black hole systems. Objects with higher Eddington ratios have softer X-ray spectra. Can we apply this result to much more massive black hole systems such as QSOs? If so, X-ray observations will give us valuable insight into the physics of QSOs. Among QSOs, X-ray spectral index is part of a large set of correlated optical and UV observational properties, especially optical Fe II and [O III] strengths in the Hβ region. To investigate whether this set of correlations is related to Eddington ratio, we use as probes, BALQSOs that have been suggested to be youthful super-accretors. We conducted infrared spectroscopy of the Hβ rest wavelength region for a sample of BALQSOs and compared line measurements with those for high and low redshift non-BAL QSOs. Hβ line widths and bolometric luminosity are used to calculate QSO black hole masses and Eddington ratios. Our results support the hypothesis that optical Fe II and [O III] line strengths are Eddington ratio indicators in QSO central engines. A possible explanation is that strong Fe II and weak [O III] indicate abundant cold gas that could fuel near Eddington accretion.     

一种香豆素并杂环衍生物分子结构及红外光谱的理论研究

基于Gaussian09W软件,采用密度泛函理论（Density Functional Theory,DFT）的B3LYP方法,在6-311G（d）基组水平上优化了一种香豆素3,4-并六元杂环衍生物分子的结构,得到其最稳定构型、分子能量及HOMO、LUMO轨道能量。在优化结构的基础上,用同样的方法计算了该分子的振动频率,频率分析证明了该优化结构为最稳定结构。利用分子的振动频率数据绘制了标题分子的红外光谱图,对其红外光谱峰位进行了归属。     

Vertical wavenumber spectra of atmospheric ozone measured from ozonesonde observations

Vertical profiles of ozone have been measured at balloon altitudes. Our purpose is to examine the character of vertical wavenumber spectra of ozone fluctuations, to assess the possible roles of gravity wave field in ozone fluctuations, and to determine dominant vertical wavelengths of ozone spectra. Vertical wavenumber spectra of 12 ozone fluctuations obtained during June–August 2003 are presented. Results indicate that mean spectral slopes in the wavenumber range from 4.69 × 10⁻⁴ to 2.50 × 10⁻³ cyc/m are about −2.91 in the troposphere and −2.87 in the lower stratosphere, which is close to the slope of −3 predicted by current gravity wave saturation models. The consistency of the observed spectral slopes with the value of −3 predicted by current gravity wave saturation models suggests that the observed ozone fluctuations are due primarily to atmospheric gravity waves. At m = 1/(1000 m) the mean spectral amplitude is over 30 times larger in the lower stratosphere than in the troposphere. Mean vertical wavenumber spectra in area-preserving form reveal dominant vertical wavelengths of ∼2.6 km in the troposphere and ∼2.7 km in the lower stratosphere, which is consistent with the values varying between 1.5 and 3.0 km estimated from the velocity field and temperature field at these heights.     

考虑模型抖振力跨向不完全相关性效应的气动导纳识别

首先通过考虑节段模型上抖振力跨向不完全相关性效应推导了节段模型风洞试验中作用在模型断面上的分布抖振力谱和由底支式天平测到的模型总抖振力谱之间的关系。然后,以准平板断面为例,进行了格栅湍流场节段模型的测力和同步测压试验,获得了模型总抖振力谱以及模型抖振力跨向相关性函数。接着,采用等效导纳法以及抖振力自谱和抖振力脉动风速交叉谱综合残量最小二乘法分别识别了准平板节段模型等效气动导纳和六分量气动导纳,讨论了模型抖振力跨向不完全相关性效应对气动导纳识别结果的影响,并把识别得到的准平板断面气动导纳与平板断面气动导纳的理论结果---Sears 函数进行了比较。结果表明:忽略抖振力跨向不完全相关性效应(即假设节段模型分布抖振力沿跨向完全相关)而直接采用平均抖振力作为断面上分布抖振力的传统方法会导致气动导纳识别结果偏小,并且,其偏小程度会随着频率的增加而增加;此外,相对于抖振升力和扭矩相关的气动导纳分量而言,由于抖振阻力的跨向相关性比抖振升力和扭矩的跨向相关性显得更弱,因此抖振力跨向不完全相关性效应对阻力相关气动导纳分量识别结果的影响更大;利用识别得到的六分量气动导纳反算的作用在模型上的分布抖振力谱与试验中实测结果非常接近,经抖振力跨向不完全相关性效应修正后的竖向脉动风速对应的升力和扭矩气动导纳分量的识别结果与Sears函数也比较接近,从而验证了用于六分量气动导纳识别的自谱-交叉谱综合最小二乘法的可靠性。     

临近空间大气中子诱发电子器件单粒子翻转 数值仿真研究

大气中子作为临近空间主要的辐射粒子,能够诱发电子器件发生单粒子翻转效应,严重威胁着临近空间飞行器安全、可靠地工作。文章研究了临近空间大气中子在不同时间、经度、纬度、高度下的能谱,计算了静态存储器（SRAM）中的IMS1601芯片在不同能量各向同性的中子入射下的翻转截面,在国内首次计算出任意两个临近空间位置上飞行器的IMS1601芯片的翻转率,并且对计算结果进行了验证。     

Spectral characteristics of electron fluxes at L < 2 under the Radiation Belts

The paper presents the analysis of experimental data on electron fluxes with energies 10 keV–10 MeV. Data were obtained during 1978–2005 years in different space experiments (COSMOS-900, MIR Space Station, ACTIVE, SAMPEX, CORONAS-I, CORONAS-F, NOAA POES-17, TATYANA and others). Two areas of electron flux enhancements are studied in the paper: the near-equatorial (L < 1.2) zone and the middle-latitude (1.2 < L < 1.9) zone. It is shown that electron flux enhancements are regularly registered at L < 2 and the observed formations have some typical features. Electron peaks at L < 1.2 appear sporadically while peaks at 1.2 < L < 1.9 are observed regularly. The approximations of spectra by several functions including kappa-function are presented.