Recursive method for opacity expansion at finite temperature

Using a reaction operator approach,we derive the multiple-scattering induced gluon number distribution function to all orders in powers of opacity at finite temperature.The detailed balance effect is analyzed by taking into account both gluon emission and absorption in a thermal medium.We also calculate virtual corrections and show that the infrared divergence cancels out in the gluon distribution function at finite temperature.     

可X射线显影的新型碘代聚碳酸酯的设计与合成

以丝氨醇、 4-碘苯甲酰氯和氯甲酸乙酯为原料, 通过酰胺化和分子内关环两步反应合成了一种新型的碘代环碳酸酯功能单体——4-碘-N-(2-氧代-1,3-二噁烷-5-基)苯甲酰胺(IBTMC). 以异戊醇为引发剂, 1,5,7-三叠氮双环(4.4.0)癸-5-烯(TBD)为催化剂, 使IBTMC与三亚甲基碳酸酯(TMC)进行开环共聚, 合成了一系列具有X射线不透过性的碘代聚碳酸酯材料, 并采用核磁共振氢谱( ¹H NMR)、 凝胶渗透色谱(GPC)、 差示扫描量热仪(DSC)、 热重分析(TGA)和X射线计算机断层成像系统(Micro-CT)表征了其化学结构与组成、 分子量与分子量分布、 热力学性能及X射线不透过性. 研究结果表明, 本文合成的碘代聚碳酸酯具有较窄的分子量分布、 良好的热稳定性及可调的X射线不透过性. 小鼠体内埋置实验结果表明, 碘代聚碳酸酯具备体内X射线成像的能力.     

辐射加热Al等离子体的吸收谱实验

报道了辐射加热Al样品的K壳层辐射吸收谱实验. 在神光Ⅱ激光装置上,将8路主激光注入锥柱型金腔产生高温辐射源,利用该辐射源加热腔内的Al薄膜样品,产生温度达到几十电子伏的热稠密等离子体. 相对主激光延迟一定时间后,利用第9路激光短脉冲聚焦打靶加热金盘,产生短脉冲X光点光源. 通过测量075—085nm波长范围内未经样品衰减以及经过样品衰减后的背光源辐射光谱,得到了Al样品的K壳层吸收谱. 利用细致谱线计算的吸收谱对实验光谱进行拟合,确定了Al样品等离子体的电子温度. 关键词： Al等离子体 吸收谱 不透明度     

Exact results in modeling planetary atmospheres—III.: The general theory applied to the Earth's semi-gray atmosphere

We apply the semi-gray model of our previous paper to the particular case of the Earth's atmosphere, in order to illustrate quantitatively the inverse problem associated with the direct problem we dealt with before. From given climatological values of the atmosphere's spherical albedo and transmittance for visible radiation, the single-scattering albedo and the optical thickness in the visible are inferred, while the infrared optical thickness is deduced for given global average surface temperature. Eventually, temperature distributions in terms of the infrared optical depth will be shown for a terrestrial atmosphere assumed to be semi-gray and, locally, in radiative and thermodynamic equilibrium.     

Exact results in modeling planetary atmospheres—II. Semi-gray atmospheres

We solve the radiative transfer equation for a semi-gray planetary atmosphere in radiative equilibrium, in an attempt to define an entirely analytical non-gray model atmosphere of finite optical thickness. The salient feature of the model is that the incident solar radiation is partitioned between two adjacent spectral domains—the “visible” and the “infrared”—in each of which the atmosphere's (effective) opacity is assumed to be independent of frequency (the semi-gray assumption). We envisage a plane-parallel atmosphere illuminated by a beam of parallel radiation and bounded below by a partially reflecting and emitting ground. The former emits infrared radiation, induced by the absorption of radiation both visible and infrared, deriving from the external irradiation as well as from the emission of the planet's surface layer. For an atmosphere with given single-scattering albedos and optical thicknesses in both the visible and infrared domains, we compute the temperature at every depth of the atmosphere, as well as the ground's temperature.     

Opacities of high temperature highZ plasmas

A procedure is described for computation of opacities for highZ plasmas. Bound-bound, bound-free, free-free and scattering processes are considered. The inputs for these have been obtained by solving IEEOS form of Saha’s equation. Detailed calculations of opacities have been done for tungsten and uranium up to 10 keV of temperature. Preliminary results have been presented at the Nucl. Phys. and Solid State Phys. Symp., Dept. of Atom. Energy, held at Ahmedabad, India (December 1976).     

辐射加热Al等离子体的吸收谱实验

报道了辐射加热Al样品的K壳层辐射吸收谱实验. 在神光Ⅱ激光装置上，将8路主激光注入锥柱型金腔产生高温辐射源，利用该辐射源加热腔内的Al薄膜样品，产生温度达到几十电子伏的热稠密等离子体. 相对主激光延迟一定时间后，利用第9路激光短脉冲聚焦打靶加热金盘，产生短脉冲X光点光源. 通过测量075—085nm波长范围内未经样品衰减以及经过样品衰减后的背光源辐射光谱，得到了Al样品的K壳层吸收谱. 利用细致谱线计算的吸收谱对实验光谱进行拟合，确定了Al样品等离子体的电子温度.     

辐射加热铝Ka吸收谱测量

 铝K_a吸收谱是诊断辐射加热等离子体温度的重要方法之一。在星光Ⅱ激光装置上，利用激光金膜相互作用产生的X光辐射加热其背侧的铝夹层样品，采用天津Ⅲ号胶片记录的PET晶体谱仪测量了不同激光和样品参数条件下的铝Ka吸收谱。实验观察到非常清晰的类氦到类氟铝离子Ka吸收谱线，采用细致组态模型开展了铝Ka吸收谱的模拟计算，模拟计算结果与实验结果符合得较好，研究结果可应用于辐射不透明度样品温度诊断。     

平均原子模型中谱线位置偏移对辐射不透明度的影响

使用平均原子(average atom,AA)模型计算了局域热动平衡近似下的Fe,Br等离子体的辐射不透明度.对AA模型中跃迁系的跃迁能量引入了统计修正，修正后的谱线位置与细致谱项模型的结果更接近，但仍然存在差距，进一步减小这种差距需要考虑等离子体的价态分布.研究了AA模型中这种谱线位置移动对平均不透明度的影响，计算了Fe等离子体等温度系列的平均不透明度，发现这种修正对于平均不透明度的影响是比较明显的.     

电子传导不透明度计算

基于含温有界相对论Dirac自洽场原子模型,采用电子-离子散射机制,在Born近似下,计算了部分离化等离子体物质的电子传导不透明度(Electron Conductive Opacity)。以铯(Cs)为例,同他人结果作了比较,给出钛(Ti)元素温度kT=10～10~3eV,密度ρ=0.1ρ_0～10ρ_0范围的电子传导不透明度K_C。