脉冲星导航的整周模糊度解算方法研究

脉冲相位是X射线脉冲星导航方法的基本观测量,在测量的脉冲相位与预报相位比对的过程中存在整周期模糊度问题．借鉴GPS载波相位模糊度的解算方法,提出了单差搜索法、最小二乘搜索法和模糊度函数法3种空间搜索方法用以解算脉冲星导航系统的整周模糊度,并针对地球卫星完全迷失的情况进行了搜索仿真验证．结果表明,这3种方法都能够准确地解算出整周模糊度,均可用于脉冲星导航系统的在轨解算．其中最小二乘搜索法的性能稳定,搜索速度快;模糊度函数法搜索速度慢,但适用于装配单X射线探测器的脉冲星导航系统．     

铝合金2A12在热冲击条件下的力学性能

测试并确定航空航天材料在复杂高速热冲击条件下的强度极限等关键参数,对于航空航天材料和结构的可靠性评定、寿命预测以及高速飞行器的安全设计具有重要的意义.针对强度设计手册中没有航空航天材料在高速热冲击环境下的强度极限等表征参数的现状,使用自行研制的高速飞行器瞬态气动热试验模拟系统,对铝合金材料2A12在多种不同的瞬态热冲击条件下,进行气动加热模拟与热载联合试验研究,得到在瞬态热、力学环境的共同作用下铝合金2A12材料的强度极限等力学性能变化状况.为研究分析航空航天材料和结构在高速热冲击环境下的承载能力和结构减重提供可靠依据.      

太阳硬X射线爆简单脉冲峰的理论模型

ＳＭＭ卫星上γ射线谱仪（ＧＲＳ）于１９８０年２月至１９８２年１２月间，观测到１０３个强硬Ｘ射线爆发。根据它们的时间轮廓图，发现其中的２４个事件含有变化幅度大，时间轮廓平滑的简单脉冲峰。２４个峰在５４－１００ｋｅＶ能道的统计结果显示，时间轮廓的上相斜率与下降相斜率具有较好的相关性，相关系数达０．８０，且上升相斜率略大于下降相斜率，平均值比值约为１．３７，为了定理比较，根据它们斜率的平均值构造成了一个     

JUXTA: A new probe of X-ray emission from the Jupiter system

For the future Japanese exploration mission of the Jupiter’s magnetosphere (JMO: Jupiter Magnetospheric Orbiter), a unique instrument named JUXTA (Jupiter X-ray Telescope Array) is being developed. It aims at the first in-situ measurement of X-ray emission associated with Jupiter and its neighborhood. Recent observations with Earth-orbiting satellites have revealed various X-ray emission from the Jupiter system. X-ray sources include Jupiter’s aurorae, disk emission, inner radiation belts, the Galilean satellites and the Io plasma torus. X-ray imaging spectroscopy can be a new probe to reveal rotationally driven activities, particle acceleration and Jupiter–satellite binary system. JUXTA is composed of an ultra-light weight X-ray telescope based on micromachining technology and a radiation-hard semiconductor pixel detector. It covers 0.3–2 keV with the energy resolution of <100 eV at 0.6 keV. Because of proximity to Jupiter (∼30 Jovian radii at periapsis), the image resolution of <5 arcmin and the on-axis effective area of >3 cm² at 0.6 keV allow extremely high photon statistics and high resolution observations.     

Observations of supergiant fast X-ray transients with LOFT

Supergiant fast X-ray transients are a subclass of high mass X-ray binaries displaying a peculiar and still poorly understood extreme variability in the X-ray domain. These sources undergo short sporadic outbursts (_LX∼$L_{\text{X}}\sim$ 10³⁶–10³⁷ erg s⁻¹), lasting few ks at the most, and spend a large fraction of their time in an intermediate luminosity state at about _LX∼$L_{\text{X}}\sim$ 10³³–10³⁴ erg s⁻¹. The sporadic and hardly predictable outbursts of supergiant fast X-ray transients were so far best discovered by large field of view (FOV) coded-mask instruments; their lower luminosity states require, instead, higher sensitivity focusing instruments to be studied in sufficient details. In this contribution, we provide a summary of the current knowledge on supergiant fast X-ray transients and explore the contribution that the new space mission concept LOFT, the Large Observatory for X-ray Timing, will be able to provide in the field of research of these objects.     

X-ray pulsar-based navigation system with the errors in the planetary ephemerides for Earth-orbiting satellite

The objective of this paper is to investigate and reduce the impact of the errors in the planetary ephemerides on X-ray pulsar-based navigation system for Earth-orbiting satellite. Expressions of the system biases caused by the errors in the planetary ephemerides are derived. The result of investigation has shown that the impact of the error in Earth’s ephemeris is must greater than the errors in the other ephemerides and would greatly degrade the performance of X-ray pulsar-based navigation system. Moreover, the system bias is modeled as a slowly time-varying process, and is handled by including it as a part of navigation state vector. It has been demonstrated that the proposed navigation system is completely observable, and some simulations are performed to verify its feasibility.     

H-450 X射线参考辐射质的研建及验证

根据PTB和ISO 4037-1:2019要求,关于高空气比释动能系列（H系列）X射线参考辐射质的推荐数据,外推得出H-450的附加过滤为6.24 mm Cu,第一半值层（HVL_1st）为(5.39~5.52)mm Cu,平均光子能量为(214.25~214.78)keV,剂量率为11.51 Gy/h（距离焦斑为1 m处,管电流为10 mA）。随后,使用PTW32005电离室作为测量器具,采用半值层法建立H-450 X射线参考辐射质,得出HVL_1st为5.37 mm Cu,第二半值层（HVL_2nd）为5.97 mm Cu,同质系数为0.9。最后,使用PTW30013次级标准电离室测量得出H-450 X射线参考辐射质下距离焦斑1 m,管电流为10 mA时的剂量率值为11.98 Gy/h,与理论值的相对误差为4.07 %。采用MCNP 5软件对H-450 X射线参考辐射质进行能谱模拟并计算得出其平均光子能量为200.4 keV。     

航空发动机球轴承剥落故障模式分析

为研究航空发动机球轴承的剥落故障模式,利用原子发射光谱技术、自动磨粒分析技术、铁谱技术及能谱分析技术对球 轴承加速等效试验滑油中磨粒的数量、大小、形貌及成分等信息进行分析。结果表明：金属颗粒污染物导致轴承出现初始疲劳剥 落;球轴承剥落的特征磨粒为滚动疲劳磨粒和球形磨粒,内衬套微动磨损的特征磨粒为铁的黑色氧化物和红色氧化铁磨粒;临近 轴承失效时,滑油中Fe元素质量分数由7.49×10 -6 增大至21.74×10 -6 ,特征磨粒数量也由48.9个/mL急剧增加至1433.8个/mL,且特 征磨粒直径主要分布在25～50 μm。金属颗粒污染物的存在使轴承承力内半圈滚道加速出现接触疲劳剥落,滚道剥落到一定程 度后,在轴向力、摩擦力及预紧力等综合作用下在内衬套与承力内半圈接触处发生微动磨损,进一步加剧了滚道的疲劳剥落,最终 导致球轴承失效。     

Sun CubE OnE: A multi-wavelength synoptic solar micro satellite

The Sun cubE onE (SEE) is a 12U CubeSat mission proposed for a phase A/B study to the Italian Space Agency that will investigate Gamma and X-ray fluxes and ultraviolet (UV) solar emission to support studies in Sun-Earth interaction and Space Weather from LEO. More in detail, SEE’s primary goals are to measure the flares emission from soft-X to Gamma ray energy range and to monitor the solar activity in the Fraunhofer Mg II doublet at 280 nm, taking advantage of a full disk imager payload. The Gamma and X-ray fluxes will be studied with unprecedented temporal resolution and with a multi-wavelength approach thanks to the combined use of silicon photodiode and silicon photomultiplier (SiPM) -based detectors. The flare spectrum will be explored from the keV to the MeV range of energies by the same payload, and with a cadence up to 10 kHz and with single-photon detection capabilities to unveil the sources of the solar flares. The energy range covers the same bands used by GOES satellites, which are the standard bands for flare magnitude definition. At the same time SiPM detectors combined with scintillators allow to cover the non-thermal bremsstrahlung emission in the gamma energy range. Given its UV imaging capabilities, SEE will be a key space asset to support detailed studies on solar activity, especially in relation to ultraviolet radiation which strongly interacts with the upper layers of the Earth’s atmosphere, and in relation to space safety, included in the field of human space exploration. The main goal for the UV payload is to study the evolution of the solar UV emission in the Mg II band at two different time scales: yearly variations along the solar cycle and transient variations during flare events. The Mg II index is commonly used as a proxy of the solar activity in the Sun-as-a-star paradigm, in which solar irradiance variations in the UV correlate with the variations in stratospheric ozone concentrations and other physical parameters of the Earth high atmosphere. SEE data will be used together with space and ground-based observatories that provide Solar data (e.g. Solar Orbiter, IRIS, GONG, TSST), high energy particle fluxes (e.g. GOES, MAXI, CSES) and geomagnetic data in a multi-instrument/multi-wavelength/multi-messenger approach.