A model for the Balmer pseudocontinuum in spectra of type 1 AGNs

Here we present a new method for subtracting the Balmer pseudocontinuum in the UV part of type 1 AGN spectra. We calculate the intensity of the Balmer pseudocontinuum using the prominent Balmer lines in AGN spectra. We apply the model on a sample of 293 type 1 AGNs from SDSS database, and found that our model of Balmer pseudocontinuum + power law continuum very well fits the majority of AGN spectra from the sample, while in ∼$\sim$15% of AGNs, the model fits reasonable the UV continuum, but a discrepancy between the observed and fitted spectra is noted. Some of the possible reasons for the discrepancy may be a different value for the optical depth in these spectra than used in our model or the influence of the intrinsic reddening.     

What we knew,what we know and what we will know about cosmic gamma-ray bursts

The paper is devoted to the present crisis in the field of cosmic gamma-ray bursts. There are two different paradigms of the phenomenon, which have practically equal numbers of supporters. The cosmological one associates bursts with collisions of compact objects at distances up to those with red-shifts of about 1–2. The galactic paradigm assumes that bursts are generated by neutron stars in the extended galactic halo. The present situation is shown to be very close to the ultimate establishment of the paradigm of the origin of cosmic gamma-ray bursts.     

面向太空环境应用的抗辐照有源光纤特性研究

针对太空恶劣辐射环境会造成光器件的光学性能下降或失效的问题,利用改良化学气相沉积法(MCVD)结合原子层沉积(ALD)掺杂技术制备铋铒共掺光纤(BEDF)和掺铒光纤(EDF),经不同辐照剂量的伽马射线处理后,对它们的光谱特性进行对比研究。光纤样品分别经0.3kGy、0.5kGy、0.8kGy和1.5kGy辐照处理,对比光谱发现BEDF的辐照诱导损耗(RIA)的增幅明显低于EDF,特别是经1.5kGy的辐照处理后,EDF的RIA比BEDF高1.93dB/m。EDF的荧光强度随辐照剂量的增加而降低,且低于未辐照前的荧光强度;而对于BEDF而言,其荧光强度随辐照剂量的增加先增加后减弱,且均高于未辐照的荧光强度。实验结果表明,BEDF具有一定抗辐照特性,对应用于太空环境具有重要研究意义。     

碳纤维增强树脂基复合材料壳体相贯线孔加工工艺

介绍一种用于碳纤维复合材料大直径不垂直相贯线孔加工方法。综合考虑了加工温度,加工质

量,排屑及加工效率等问题。结果表明,采用一种简易的加工工装保证了孔的尺寸及位置精度,使相贯线孔能

够一次性加工完成。通过对传统磨头的工艺改进解决了排屑及散热问题,并提高了复合材料的表面加工质量。

     

On the Stark broadening of the Re II spectral lines

Stark broadening parameters - full widths at half maximum (FWHM) and shifts for 11 Re II lines have been calculated. The plasma parameters used were electron density of ${10}^{17}$ cm^?3 and temperature from 5 000 K to 80 000 K. Calculations were performed using the simplified modified semiempirical (SMSE) approach and compared with calculations by Cowley’s approximative Stark broadening formula at 10000 K, usefull in spectrum synthesis. The results have also been considered in the atmosphere model of A type star and for DB white dwarfs.     

Stark broadening parameters of the singly ionized sulfur: S II

Stark broadening parameters are useful in solving various problems e.g., in astrophysics, opacity calculations, design of lasers, laser-produced plasma and for the evaluation of the physical conditions in stellar atmospheres. Our objectives in this research work are to obtain, for electron collisions, new atomic data for Stark broadening of astrophysically important S II lines using semi-classical perturbation (SCP) and modified semi-empirical (MSE) theory with the needed energy levels and oscillator strengths from NIST database. After calculating the Stark broadening data, we compared them with experimental and theoretical data.