单峰伽玛射线暴光变曲线的FWHM与持续时间之间的关系

探讨了具有单峰结构的伽玛射线暴(GRB)光变曲线的半峰全宽(FWHM)与伽玛暴持续时标T之间的关系.用目前公认的半经验公式——Kocevski, Ryde & Liang (2003)模型对108个单峰光变曲线数据样本进行拟合,选取59个χ²<2的有效拟合样本计算FWHM,然后对FWHM与T进行相关分析.两者能较好地用幂率关系进行拟合为T≈BW^a,其中W为光变曲线的 关键词： 伽玛射线暴(GRB) 光变曲线 相关分析     

Properties of SN Ia progenitors from light curves and spectra

With recent advances in theory and observations, direct connections emerge between the progenitors of Type Ia Supernovae (SNe Ia) and the observed light curves and spectra. A direct link is important for our understanding of the supernovae physics, the diversity of SNe Ia and the use of SNe Ia for high-precision cosmology because the details of the explosion depends sensitively on the initial conditions and the explosion scenario(s) realized in nature. Do SNe Ia originate from SD- or DD systems, and do they lead to M_Ch mass explosions or dynamical mergers? Does the statistical distribtion of SNe Ia depend on their environment which can be expected to change with redshift? In this contribution, we will exam from the theoretical point of view the tell-tails for this connection, their consistency with the observations, and future directions. In a first section, we present the physics of the explosion, light curves and spectral formation in a nutshell to help understanding the connection. For details of the progenitor evolution and explosion physics, we refer to reviews and the other contributions in this issue. Each of the topical sections starts with a brief general review followed by a more detailed discussion of specific results. Because the youth of the field, some bias is unavoidable towards results obtained within our collaborations (and FSU). The imprint of the metallicity, progenitor stars and properties such as the central density of the exploding WD are presented. IR spectroscopy, polarimetry and imaging of SNR remnants are discussed as a tool to test for the WD properties, magnetic fields and asymmetries. We discuss different classes of Type Ia supernovae, and their environment. Possible correlations between the spectroscopic and light curve properties of SN Ia are discussed. Finally, the overall emerging picture and future developments are discussed.     

基于光纤四波混频波长转换和色散的慢光实验研究

对基于光纤四波混频（FWM）波长转换和色散的慢光实现进行了详细和系统的实验研究.首先,实验测定了高非线性光纤中FWM带宽约为40 nm,从而确定了慢光的可调谐带宽;接着,在普通单模光纤和色散补偿光纤（DCF）中针对500 MHz正弦信号和100 ps短脉冲信号分别实现了34和198 ns的脉冲延迟,在DCF中还实现了209 ns的脉冲提前.讨论了增大延迟量的方法,指出随着宽带FWM波长转换的实现和大色散光纤的应用有望获得微秒量级的大延迟量,从而为高性能光纤延迟线和全光缓存器等应用提供支持. 关键词： 慢光 四波混频 色散     

Improving light trapping and conversion efficiency of amorphous silicon solar cell by modified and randomly distributed ZnO nanorods

Three-dimensional （3D） nanostructures in thin film solar cells have attracted significant attention due to their appli- cations in enhancing light trapping. Enhanced light trapping can result in more effective absorption in solar cells, thus leading to higher short-circuit current density and conversion efficiency. We develop randomly distributed and modified ZnO nanorods, which are designed and fabricated by the following processes： the deposition of a ZnO seed layer on sub- strate with sputtering, the wet chemical etching of the seed layer to form isolated islands for nanorod growth, the chemical bath deposition of the ZnO nanorods, and the sputtering deposition of a thin Al-doped ZnO （ZnO：Al） layer to improve the ZnO/Si interface. Solar cells employing the modified ZnO nanorod substrate show a considerable increase in solar energy conversion efficiency.     

用高亮度LED和简便数据处理方法测定椭圆偏振光的椭圆曲线

通过建立椭圆偏振光在β方向上的光振动大小与检偏器在β+90°方向时光电检测器所测光强之间的关系式,以高亮度LED为光源,可简便地测定椭圆偏振光的椭圆曲线.     

Afterglow mechanism and thermoluminescence of red-emitting CaS:Eu,Pr phosphor with incorporated Li ion upon visible light irradiation

This paper reports on the afterglow mechanism and thermoluminescence (TL) of a red-emitting CaS:Eu²⁺,Pr³⁺ phosphor with incorporated Li⁺ ion upon irradiation by visible light (D₆₅ lamp). In the TL glow curve of the CaS:Eu²⁺,Pr³⁺ phosphor, a TL peak was observed near 120 °C. The luminescence center of the CaS:Eu²⁺,Pr³⁺ phosphor was the Eu²⁺ ion and the trap depth of the CaS:Eu²⁺,Pr³⁺ phosphor with the cation vacancy (Trap 1) which formed by incorporation of the Pr³⁺ ion was 0.202 eV. A cation vacancy (Trap 2) was formed by incorporation of the Li⁺ ion in the CaS:Eu²⁺,Pr³⁺ phosphor. In the TL glow curve of the CaS:Eu²⁺,Pr³⁺ phosphor with incorporated Li⁺ ion, two TL peaks were observed near 120 and 200 °C. The TL luminance of the CaS:Eu²⁺,Pr³⁺ phosphor with incorporated Li⁺ ion increased with an increase in the initial Li/Ca atomic ratio. The two TL peaks moved to the high-temperature side with an increase in heating rate. The cation vacancy (Trap 2) calculated from the Hoogenstraaten method was 0.118 eV. The afterglow time of the CaS:Eu²⁺,Pr³⁺ phosphor with incorporated Li⁺ ion was prolonged by generation of a shallow trap.     

激光陀螺光强扫模曲线模高的影响因素与改善途径分析

激光陀螺光强扫模曲线是陀螺稳频的依据,也是激光陀螺环形激光器振荡特性的基本表征,同时也是陀螺性能好坏的重要标志之一.通过引入新的参量——模高,描述光强扫模曲线的其他特征.光强扫模曲线模高是在腔长变化一个0.6328μm条件下对应光强的最大变化量,是反映光强扫模曲线尖锐度的特征量,该特征量与陀螺稳频精度、稳频响应时间等物...     

Line-shape of light absorption by excitons in one-, two- and three-dimensional molecular structures

Within the framework of the dipole approximation the line-shape of light absorption for exciton transitions between narrow bands in one-, two- and three-dimensional periodic structures are calculated. Exciton damping due to lattice imperfections is accounted for as a frequency independent parameter. The obtained analytical expressions allow analysis of the line-shape for different space dimensions of structure depending on bandwidth difference, damping and temperature.