一般加速带电带磁的动态黑洞中标量场的熵

在一般加速带电带磁的动态黑洞中,化简Klein-Gordon场方程,利用乌龟坐标变换,得到在视界面附近的辐射温度.用薄膜brick-wall模型,选择适当的截断因子和薄膜厚度,得到在视界面附近薄膜上的熵,结果表明黑洞熵与视界面积成正比. 关键词： 黑洞 Hawking温度 薄膜brick-wall模型 熵     

Tunnelling effect of the non-stationary Kerr black hole

Extending Parikh and Wilczek＇s work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilto-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.     

静态球对称黑洞热力学与爱因斯坦场方程

建立在广义相对论基础上的黑洞理论与热力学定律之间有着深刻的内在联系.具体考虑球对称黑洞,研究表明通过史瓦西黑洞和Reissner-Nordstrom黑洞在其视界附近的爱因斯坦场方程可以直接得到对应的黑洞热力学第一定律.这揭示了爱因斯坦引力场方程与黑洞热力学的关系,表明了在广义相对论理论框架下黑洞热力学规律的必然性.     

La1-x／2Pr1-x／2SrxCuO4的电输运性质和超导电性

La1-x/2Pr1-x/2SrxCuOy(LPSCO)多晶样品采用传统的固相反应法制备.X射线衍射表明:LPSCO具有典型的空穴搀杂的T-214相的结构.磁化率测量显示:Sr搀杂在0.05≤x≤0.30范围内具有超导转变;Tc随x的增大呈抛物线形式变化,且在x=0.18时达到最大值28K.电阻的测量显示:随搀杂量的增大,系统呈现从绝缘到半导体,最后到金属的导电行为的变化;在欠掺杂区,正常态电阻温度关系符合ρ(T)=ρ0 αT-ClnT;而在过掺杂区,对数项消失.本文从替代所引起的晶体结构和载流子特性变化解释了Sr掺杂样品的电输运行为和超导特性.     

持久光谱烧孔动力学的理论模型和实验研究

建立了单光子光化烧孔的三能级模型，求解了反映质子转位变构机制的速率方程组，推导了成孔过程的动力学特性，获得了可与实验进行比较的解析解．用时域和频域两种方法测量了ＴＨＰ／ＰＭＭＡ和ＴＭＰ／ＰＭＭＡ薄膜样品光谱烧孔的动力学过程，得到与理论分析一致的规律，并测得了有效成孔速率和成孔时间等参数．这些参数对于评价频域光存贮材料性能有一定意义．     

The Tunneling Radiation Characteristics of Kerr-Newman de Sitter Black Hole

The strictly thermal spectrum in dragging coordinate system and the tunneling radiation characteristics of stationary axisymmetry Kerr-Newman de Sitter black hole is studied. The result shows that the tunneling rates at the event and cosmological horizon are related to the change of Bekenstein-Hawking entropy and that the factual radiation spectrum is not strictly pure thermal. Thus an exact correction to the Hawking thermal spectrum is present.     

On the observation of electron–hole liquid luminescence under low excitation in Al2O3‐passivated c‐Si wafers

We report on low‐temperature photoluminescence (PL) from aluminum oxide (Al₂O₃)‐passivated c‐Si wafers, which surprisingly exhibits clear signature of the formation of the so‐called electron–hole liquid (EHL), despite the use of excitation powers for which the condensed phase is not usually observed in bulk Si. The elevated incident photon densities achieved with our micro‐PL setup together with the relatively long exciton lifetimes associated with a good quality, indirect band‐gap semiconductor such as our float‐zone c‐Si, are considered the key aspects promoting photogenerated carrier densities above threshold. Interestingly, we observe a good correlation between the intensity of the EHL feature in PL spectra and the passivation performance of the Al₂O₃ layer annealed at different temperatures. The change in the extension of the sub‐surface space‐charge region that results from the balance between the induced fixed charge in the Al₂O₃ and the defect states at the alumina/Si interface is at the origin of the observed correlation. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

石墨烯包层结构光子晶体光纤的高双折射特性

将PG玻璃材料制作成的椭圆纤芯引入光子晶体光纤中心,设计了一种石墨烯包层结构的高双折射光子晶体光纤.基于有限元法对该光纤的双折射特性进行了数值模拟,研究了光纤孔径比、孔间距和纤芯椭圆对双折射特性的影响,并以该光子晶体光纤的模场面积和限制性损耗为依据进行了优化.研究结果表明:在波长1 550nm处,光纤双折射率高达0.13,满足高双折射要求;两偏振方向模场面积小于0.7μm2,限制性损耗低于10-6 dB/km.该光纤可有效保持光在传输系统中的偏振状态,为高稳定性超连续谱的产生提供依据.