国内外航天器密封舱主结构材料的选用

介绍了国内外航天器密封舱主结构常用的铝合金材料,并对其常规力学性能、断裂韧度、焊接性能、抗应力腐蚀性能等进行了比较。同时,结合不同的使用环境及条件对可选材料进行了分析,给出了目前及未来密封舱主结构材料的选择建议。文章研究结果可为大型航天器密封舱主结构研制提供参考。     

Multiband echo tomography of Sco X-1

We present preliminary results of a simultaneous X-ray/optical campaign of the prototypical LMXB Sco X-1 at 1–10 Hz time resolution. Lightcurves of the high excitation Bowen/HeII emission lines and a red continuum at λ_c  6000 Å were obtained through narrow interference filters with ULTRACAM, and these were cross-correlated with simultaneous RXTE X-ray lightcurves. We find evidence for correlated variability, in particular when Sco X-1 enters the Flaring branch. The Bowen/HeII lightcurves lag the X-ray lightcurves with a light travel time which is consistent with reprocessing in the companion star while the continuum lightcurves have shorter delays consistent with reprocessing in the accretion disc.     

Keck observations of ROSAT ultra-luminous X-ray source candidates

We present results of optical follow-up observations of candidate ultra-luminous X-ray sources (ULXs). Using Keck optical spectroscopy, 17 of the candidates from the Colbert and Ptak [Colbert, E.J.M., Ptak, A.F. A catalog of candidate intermediate-luminosity X-ray objects. ApJS 143, 25–45, 2002] catalog have been identified; this is one of the largest sets of optical identifications of such objects thus far. Fifteen are background active galactic nuclei (AGN); two are foreground stars in our Galaxy. These findings are consistent with background and foreground object expectations, as derived from log N–log S relations. Also, the results are briefly discussed in terms of the spiral-galaxy/ULX connection.     

正态-复合非时齐Poisson过程模型结构可靠性当量正态设计

讨论强度R～N（μ_R，_R），应力｛S（t），t∈［0，T］｝为非时齐Poisson过程模型结构可靠性当量正态设计。获得应力在设计基准期［0，T］内的最大值概率分布及统计参数估计；正态－复合非时齐Poisson过程模型结构可靠度及结构可靠性当量正态设计表达式。     

On kinematics of gas clouds in the broad-line region of active galactic nuclei and quasars

The kinematics of gas clouds in broad-line region of active galactic nuclei and quasars is considered. The motion of the clouds is governed by three forces — gravitational influence from the central supermassive body, radiational pressure from the continuum radiation, and resistance of the intercloud medium. Clouds moves radial but only outward motion gives a velocity field, which is in accordance with the observational data. The profiles of the permited lines are obtained in some simplify assumptions for the emissive capacity of the gas in clouds, and are in good agreement with the observational data. In the framework of the model under consideration there is a possibility to estimate some physical parameters of the nuclei such as mass of the central body and density of the intercloud medium.     

P1─—多面体的对偶图形的性质

本文研究了P1─—多面体与其对偶图形的对偶图形边长之间的关系问题．设P1─—多面体的边长为a，其对偶图形的对偶图形的边长为C，则其中θ1为多面体A的过顶点的相邻两校之间的夹角，θ2为多面体B的过顶点的相邻两校之间的夹角，取θ＝max｛θ1，θ1｝     

Superclustering and the large-scale structure of the universe

The spatial distribution of a complete redshift sample of nearby rich clusters of galaxies is studied. Strong superclustering, extending to very large scales (100h⁻¹Mpc), is observed in the cluster distribution. In particular, we determined and discuss below the following studies:I. The spatial correlation function of rich clusters of galaxies.II. The construction of a complete catalog of superclusters and a study of their growth (percolation).III. The finding of large-scale superclusters surrounding the giant galaxy void in Bootes.IV. The finding of a 300 Mpc void of rich clusters of galaxies.All the above studies provide evidence for the existence of large-scale structure in the universe, and reveal some of its characteristics. These findings are of importance to models of the formation of galaxies and structure in the universe.     

The structure and effects of cooling flows in clusters of galaxies

Rapidly cooling gas is commonly found near the centres of clusters of galaxies. The structure of the resulting gas flows is reviewed. Total gas cooling rates of several hundred M yr⁻¹ have been observed in a number of cases. Thermal instability and the ultimate fate of the cooled gas are discussed. The cooled gas could easily have formed a massive central galaxy.     

螺旋桨桨叶1P气动载荷研究

介绍了一种１Ｐ载荷实验研究方法－桨叶应变测试法,首先通过桨叶剖面速度三角形及气动力分析给出了１Ｐ载荷与测量应变的关系,然后通过地面试验和飞行试验进行了验证。试验结果表明,螺旋桨１Ｐ载荷主要由于非对称气流流过桨盘面改变了桨叶剖面速度三角形而引起,迎角,侧滑角的增加,会产生较大的１Ｐ载荷;机动飞行,如快速拉杆,荷兰滚等也会产生较大的１Ｐ载荷。     

猎鹰9号火箭发射及箭体复用的分析

猎鹰9号火箭截至2023年年底已完成286次发射。对猎鹰9号火箭特别是Block5版本火箭的发射情况进行了完整梳理统计,重点分析了一级箭体的复用情况以及发射、回收的相关能力保障,对火箭的经济性和未来前景作了预测。