活笥银粉中微量铜铁的测定

提出用空气－乙炔火焰原子吸收光谱法来测定银锌电池活性银粉中的微量铜铁，并对测定条件和干扰因素进行了综合考虑，该测定方法具有灵敏度、精确度高，干扰小，选择性和重现性好等优点。测定样品微量铜铁含量的相对标准偏差均小于１.5%(n=8）。标准加入回收率均在（９７.00-102.00)%(n=5)范围内，完全适用于银锌电池活性银粉中微量铜铁含量的控制和样品系统分析，实际应用中取得了很好的效果。     

原子氧环境效应的地面模拟技术

系统论述了原子氧和航天器表面常用聚合物材料反应的微观机理,并从宏观角度对这些材料的性能进行了评估。同时也总结了国外在原子氧防护技术研究方面所取得的最新成果。     

佘山VLBI站本振系统的性能评定

氢钟是甚长基线干涉仪(VLBI)中的一个关键系统。主要介绍与国际VLBI联测而建立的高质量频率标准的性能及氢钟的联接与技术要求。     

LiHe spectra from brown dwarfs to helium clusters

The detection of Li I lines is the most decisive spectral indicator of substellarity for young brown dwarfs with masses below about 0.06 solar mass. Due to the weakness of the Li resonance lines, it is important to be able to model precisely both their core widths and their wing profiles. This allows an adequate prediction of the mass at which Li lines reappear in the spectra of brown dwarfs for a given age, or reversely an accurate determination of the age of a cluster. We report improved line profiles and the dependence of line width on temperature suitable for modeling substellar atmospheres that were determined from new LiHe molecular potential energies. Over a limited range of density and temperature, comparison with laboratory measurements was used to validate the potential energies which support the spectral line profile theory.     

Collisional line broadening versus collisional depolarization: Similarities and differences

Within the impact approximation, collisional line broadening parameters and depolarizing and polarization transfer (population, orientation, alignment transfer) rates are complementary: both include the effect of collisional transitions between the Zeeman sublevels of a given level, or between fine or hyperfine structure levels of a given term. However, there are several differences: in line broadening, the two levels connected by the radiative transition contribute to the broadening, and there is also an interference term between these two levels, whereas only one level or two close levels are concerned in the depolarization. Another difference lies in the fact that purely elastic collisions contribute also to the line broadening, whereas they do not contribute to the depolarization. The nature of these two kinds of coefficients are recalled. Then the possibility to find some relationships or systematic trends concerning depolarization versus collisional broadening is considered. This is to answer some current questions which come from the polarization community.     

Stark broadening data for spectral lines of rare-earth elements: Nb III

The electron-impact widths for 15 doubly charged Nb ion lines have been theoretically determined by using the modified semiempirical method. Using the obtained results, we considered the influence of the electron-impact mechanism on line shapes in spectra of chemically peculiar stars and white dwarfs.     

一种用于GPS时差比对数据处理的卡尔曼滤波器设计

介绍了一种用于GPS时差比对数据处理的自适应卡尔曼滤波器,在Matlab环境下编写了离散时间形式的卡尔曼滤波算法程序,利用该算法对GPS信号与铯原子频标的时差比对数据进行了分析处理,最后介绍了该算法的数字芯片FPGA实现。     

Thermal Radiation Processes

We discuss the different physical processes that are important to understand the thermal X-ray emission and absorption spectra of the diffuse gas in clusters of galaxies and the warm-hot intergalactic medium. The ionisation balance, line and continuum emission and absorption properties are reviewed and several practical examples are given that illustrate the most important diagnostic features in the X-ray spectra.     

Switching and performance variations of on-orbit BDS satellite clocks

The information of the satellite clock switching and performance variations on-orbit of Chinese BeiDou-2 Navigation System (BDS) is not available for the public. In order to detect the BDS satellite clock switching and performances variation, we analyzed the precise clock offset products with a total duration of 5?years every BDS satellite equipped four atomic clocks from four different manufactures from January 2013 to October 2017. Three important contributions are concluded as follows. (1) It is found that the average time of on-orbit operation for BDS satellite clocks is about 1–2?years. There have been 22 times of clock switching for BDS satellites, of which the C05 and C08 satellites have been switched to the fourth (last) atomic clock. (2) There are frequent phase adjustments for BDS on-orbit satellite clocks, and the frequency series is relatively stable. Furthermore, there are semi-annual sinusoid cycles in the frequency drift series of C06 and C09 satellites. (3) The performances of MEO satellite clocks perform better than the IGSO and GEO satellite clocks. The average ten-thousand frequency stability of BDS satellite clocks is about 1E-13, which is worse than that of GPS and Galileo but better than that of GLONASS.     

精密时间频率，国防命脉所在——国防时间频率专业的发展

精密时间频率设备及其计量技术是国防科技工业的基础,总结了国防科技工业在晶体元器件、频率综合、原子频标、时间频率计量等时频领域的发展现状,并指出时间频率专业今后的发展方向。