Structures and Equation of State of ε-Fe under High Pressure

The equation of state （EOS） and the axial ratio c/a of ε-Fe at high pressures are investigated by using the gen- eralized gradient approximation （GGA） within the plane-wave pseudopotential density functional theory （DFT）. The results show that at the lower pressure, the EOS of ferromagnetic ε-Fe is consistent with the experimental result. While at higher pressure, the EOS of the nonmagnetic ε-Fe is in good agreement with the experimental result. Meanwhile, we find an obvious increase of the axial ratio c/a with pressure, and there is only a small increase with increasing temperature at high pressure.     

VISAR条纹常数的检测方法

 提出了4种可检测VISAR条纹常数的方法。在这4种方法中,DISAR和VISAR的混合测试系统对VISAR条纹常数的测定精度高,适用范围广,是一种普适方法。在不具备DISAR仪器以及DISAR、VISAR混合测试技术的条件下,也可以通过VISAR延迟时间的测定、加窗熔石英对称碰撞产生的相对标准速度源以及标检过的VISAR仪器对VISAR条纹常数进行检测。     

重玻璃高压声速精密测量与反向加载光分析技术研究

研究了重玻璃黑体窗光分析技术,提出采用无氧铜标准样品(Hugoniot参数和声速 压力曲线已知)进行反向加载,确定重玻璃窗中的波后卸载声速,分析了声速测量不确定度。获得了76～160GPa压力范围内重玻璃Hugoniot参数、冲击温度和卸载声速的实验数据,声速测量不确定度小于2%。分析比较了不同装配条件对波形质量和声速测量不确定度的影响,发展了反向加载光分析技术。     

冲击压缩LY12铝向不同充气介质卸载后的光反射率实验研究

用二级氢气炮作为冲击压缩加载工具和多通道瞬态辐射高温计作为主要测量系统,对装有初始压力为6 MPa和1.2 MPa的氦气、氘气和氢氘混合气体冲击压缩等离子体的光谱幅亮度历史进行了测量。根据实测记录信号波形的有关特征量,拟合得到了冲击压缩LY12铝基板表面光反射率R。结果发现：受冲击LY12铝基板表面对340~800 nm波长向不同充气介质氦气、氘气和氢氘混合气体等离子体卸载后的光反射率为约0.4,为静态下铝基板反射率(约0.8)的一半。并对动态加载下反射率降低的机理进行了探讨。     

激光驱动X光背光照相技术在金属靶微层裂研究中的应用探索

利用神光Ⅱ装置发射强激光一方面对铝靶进行烧蚀加载,另一方面驱动铜背光靶发射X光对铝靶微层裂产物进行针孔背光照相,结果获得了可忽略动态模糊的高清晰照片,标准丝阵检验表明分辨率优于40 m。铝靶微层裂产物照片清晰显示,靶破碎存在不同分区, 这直观揭示了靶破碎的不同机制。实验成功验证了激光驱动X光背光照相技术在金属靶微层裂研究中存在重要的应用前景。     

动高压加载下锆基金属玻璃强度测量

为了研究Zr₅₁Ti₅Ni₁₀Cu₂₅Al₉金属玻璃的高压强度特性,进行了平靶冲击实验。采用反向碰撞方式,运用DISAR技术测量金属玻璃样品/LiF窗口界面粒子速度剖面,分析粒子速度剖面获得了37~66GPa压力范围锆基金属玻璃的屈服强度和剪切模量。实验结果表明,在上述压力范围金属玻璃的屈服强度和剪切模量均显示出一定程度的压力硬化效应,分析表明金属玻璃冲击加载波阵面剪应力衰减并非由损伤/破坏或温度软化等因素导致。

     

Electrical Resistivity of Silane Multiply Shock-Compressed to 106 GPa

Since Wigner et al. proposed that hydrogen would become metallic under sufficient pressure compres- sions in 1935,scientists have paid their attention on making metallic hydrogen at high pressures, and con- siderable progresses were made in theoretical and ex- perimental researches. Nellis et al. observed that the electrical resistivity of fluid hydrogen declined by several orders of magnitude when liquid hydrogen was multiply shocked to 140 GPa, and concluded that fluid hydrogen underwent metallization phase tran- sition from semiconductor to metal in their experi- ments. Although further researches should be carried out to distinguish the highly conductive state and the metallic state of fluid hydrogen, researchers have made great efforts to find new technical approaches to de- crease the threshold pressure for hydrogen metalliza- tion. For this purpose, hydrogen-rich compounds at- tract much attention. Some researchers believed that non-hydrogen elements in those compounds may re- duce, to some extent, the activation energy of met- allization by the effect of chemical pre-compression. Silane, a typical hydrogen-rich compound of group IV hydrides, has been the subject of most of the theoretical and experimental research so far, and it was also expected to be a potential candidate for a high-To superconductor at high pressure research.[61 Compared to hydrocarbons,[71 the chemical bonds in the silane molecule are theoretically more sensitive to pressure and temperature. At sufficiently high pres- sure and temperature, the fluid silane possibly be- comes some metallic alloy consisting of hydrogen and silicon elements. Theoretical calculations showed thatthe metallic transition for the silane system may oc- cur even below 100 GPa, while there are also some other later articles that claimed that silane would re- main an insulator up to around 200 GPa and became metallic and supconducting at 220 GPa with a theo- retical Tc of 16 K. Recently, Eremets et al. have re- ported that silane can transform to metal at 50 GPa,     

类镓等电子序列PdⅩⅥ—TeⅩⅫ的4s^24p—4s4p^2,4s^24p—…

对类镓等电子序列ＧａⅠ－ＸｅⅩⅪⅤ离子４ｓ＾２４ｐ，４ｓ４ｐ＾２，４ｓ＾２５ｓ组态能级结构和组态相互作用进行了理论分析，找出沿等电子序列的变化规律。用我们提出的拟合公式预测ＳｎⅩⅩ－ＴｅⅩⅫ离子４ｓ＾２４ｐ，４ｓ４ｐ＾２，４ｓ＾２５ｓ组态能级，并给出４ｓ＾２４ｐ－４ｓ４ｐ＾２，４ｓ＾２４ｐ－４ｓ＾２５ｓ谱线波长和ＨＸＲ方法的理论计算振子强度，理论计算值与实验值进行了比较。     

类镓等电子序列ZrⅩ-RhⅩⅤ离子的4s~24p-4s~24d、4s~24p-4s4p~2、4s~24p-4s~25s、4p~3-4s~25s以及4s4p~2-4p~3跃迁谱线和振子强度的理论计算

本文对类镓等电子序列ＧａⅠ—ＸｅⅩⅩⅠⅤ离子４ｓ２４ｐ、４ｓ２４ｄ、４ｓ４ｐ２、４ｐ３和４ｓ２５ｓ组态能级结构和组态相互作用进行了理论分析，找出沿等电子序列的变化规律。用作者提出的半经验公式［１］，内插预测了ＴｃⅩⅢ离子的４ｓ２４ｐ、４ｓ４ｐ２和４ｓ２５ｓ组态能级，外推预测了ＴｃⅩⅢ—ＲｈⅩⅤ离子的４ｐ３和４ｓ２４ｄ组态能级，并给出了４ｓ２４ｐ４ｓ２４ｄ、４ｓ２４ｐ４ｓ４ｐ２、４ｓ２４ｐ４ｓ２５ｓ、４ｐ３４ｓ２５ｓ和４ｓ４ｐ２—４ｐ３谱线波长和ＨＸＲ方法理论计算振子强度。用作者提出的半经验公式对组态能级的预测值与实验值的最大偏差小于１００ｃｍ－１。     

Simulation of Ab Initio Molecular Dynamics of Shock Wave on Copper

The relation between particle velocity Up, up to 4 km/s, and shock wave velocity Us in copper has been simulated with ab initio molecular dynamics. The simulated relationship without considering the correction of zero-point and finite temperature effects is Us = 4.23 1.53Up. After considering the correction the relation becomes Us = 4.08 1.53Up, which is consistent with the experimental result.