共查询到20条相似文献,搜索用时 218 毫秒
1.
2.
飞秒激光在铝膜中驱动冲击波的特性 总被引:1,自引:0,他引:1
为探索研究飞秒激光在材料中驱动冲击波的相关特性,采用激光脉冲频域干涉测试技术对脉冲宽度35fs、脉冲能量0.7mJ、功率密度1014W/cm2量级的飞秒激光脉冲在200nm厚铝膜中驱动冲击波的过程进行了实验测量。通过测量冲击波在铝膜中的渡越时间,获得激光脉冲在铝材料中驱动的冲击波平均速度约为6km/s;通过对不同时刻铝膜自由面频域干涉场测量结果的分析,获得铝材料自由表面速度达1km/s,根据平面冲击波的关系,推算其冲击压强达到9GPa。 相似文献
3.
利用神光Ⅱ装置上搭建的用于激光冲击波实验的温度诊断系统(该系统包括高时空分辨的扫描高温计和谱时分辨的扫描高温计),以强激光加载铝材料冲击温度的测量,获得了铝材料冲击高温辐射发光谱的高时空分辨信号图像,结合灰体辐射理论模型,计算得到了冲击波速度19.06 km/s时铝材料的冲击温度达2.95 eV,该温度与SESAME库中冲击温度接近。研究结果表明采用该测温系统能够有效诊断金属材料的冲击温度,为后续进一步获取金属材料冲击温度数据奠定了基础。 相似文献
4.
5.
为了研究强脉冲激光在镁合金中诱导冲击波的衰减,采用Nd:Glass脉冲激光(1054 nm,23 ns)对AZ31B变形镁合金试样表面进行冲击,并利用响应快、测量范围大的PVDF压电膜传感器以及示波器实时测量了强脉冲激光在镁合金靶中诱导激光冲击波的相对压力.根据冲击波每次在靶材背面反射时,所经过距离的不同得到激光冲击波在镁合金中的衰减规律.结果表明,在激光能量为5J的强脉冲激光作用下,镁合金中冲击波衰减的平均速度为5.83×103 m/s,与镁合金中应力波纵波的传播速度相符;强脉冲激光诱导冲击波在镁合金中是以指数规律衰减的.试验所得分析结果对激光冲击强化镁合金的应用具有重要意义.
关键词:
激光
镁合金
压电膜传感器
衰减规律 相似文献
6.
采用一级气炮加载技术和锰铜压力计测试技术,对含初始空隙的C30混凝土在一维应变条件下的冲击特性进行了实验测量和分析.基于锰铜压力计测量的压力波形,确定了C30混凝土材料的冲击绝热关系,即冲击波速度D与波后粒子速度u之间满足线性关系.再从C30混凝土的冲击绝热数据出发,获得了计及初始空隙度0影响的多项式形式Grüneisen型状态方程中的各项系数.实测压力波形还显示:不同位置处的压力波形在迅速上升至峰值后均随时间逐渐衰减,而冲击波峰值又随传播
关键词:
Grüneisen型状态方程
冲击绝热关系
混凝土 相似文献
7.
在2009年度神光Ⅱ装置上获得了可重复的冲击波数据,并与精密标定之后的软X射线能谱仪(SXS)给出了自洽的黑腔辐射温度.在三倍频激光能量2.1 kJ、脉宽1 ns条件下,对于神光Ⅱ输运腔(Φ0.8mm×1.7 mm,LEHΦ0.38 mm)辐射温度约为180 eV,对于原型输运腔(Φ1.0 mm×2.1 mm,LEHΦ0.6 mm)辐射温度约为150 eV.采用蒙特卡罗方法编制了数值计算程序,建立了辐射温度测量不确定度评估方法;通过精密标定和多种改进
关键词:
黑腔辐射温度
冲击波速度
蒙特卡罗方法
不确定度分析 相似文献
8.
任意反射面速度干涉仪(VISAR)具有很高的测试精度, 能实现冲击波速度、粒子速度的连续测量, 是目前冲击波传播相关物理实验的主要诊断设备. 神光II高功率激光装置上的速度干涉仪其空间分辨率优于7 μm, 靶面视场约为1 mm, 探针光脉冲宽度约为 60 ns, 能满足各类冲击波相关实验的诊断. 该VISAR系统用偏振分光镜和波片系统组成了能量调节系统, 极大地方便了探针光能量和条纹相机匹配的调节; 利用新颖的探针光引入系统, 极大地提高了探针激光的能量利用率 (相对其他方法, 能量利用率提高了3倍). 该速度干涉仪已成功应用于状态方程实验、等熵压缩实验和冲击波追赶实验. 本文利用激光脉冲整形技术获得了无冲击压缩实验图像, 利用石英作为标准材料获得了聚苯乙烯 (CH)的Hugoniot数据, 利用双脉冲激光获得了石英材料中冲击波追赶 的实验图像并与理论模拟进行了对比, 实验和模拟符合得比较好. 实验结果表明, 神光II装置上的速度干涉仪能满足不同时间尺度(亚ns---几十ns) 冲击波传播相关物理实验的诊断, 为进一步开展CH的高精度Hugoniot参数测量、 高压无冲击压缩实验和冲击波时空整形实验奠定了基础. 相似文献
9.
10.
主要讨论了激光状态方程实验测量中,标准材料冲击波速度和粒子速度的线性关系式中物理量的相关性对待测材料粒子速度的影响,以及待测量材料冲击波速度和粒子速度的函数相关性对待测材料压强不确定度的影响。通过激光状态方程实验数据实例计算,定量地给出了它们对实验精度的影响。经多发次实验数据统计表明:标准材料冲击绝热参数的相关性对待测材料粒子速度相对不确定度的变化小于0.7‰,待测材料冲击波速度和粒子速度的相关性对待测材料压强相对不确定度的变化在0.5%左右。 相似文献
11.
利用二级轻气炮加载下的冲击Hugoniot线(冲击波速度D-粒子速度u关系)和粒子速度剖面测量,结合基于密度泛函理论的平面波赝势计算研究了z切LiTaO3单晶的高压相变.实验发现,D-u关系在u=0.95km/s附近出现明显拐折;实测波剖面中25.9 GPa和32.6 GPa时观测到弹-塑性双波结构,而终态压力为42.7 GPa和53.0 GPa时则为三波结构.上述结果都清楚地表明z切LiTaO3单晶冲击相变的发生,相变起始压力约为37.9 GPa.同时,理论计算的菱形相(R3c对称群)压缩线与低压实验数据符合较好,而正交相(Pbnm对称群)压缩线则与扣除热压贡献的高压实验数据相符,由此推断z-切LiTaO3的高压相为正交结构.从实验和理论上澄清了z切LiTaO3的相变起始压力和高压相晶体结构的认识,研究工作亦对类似单晶材料的冲击相变研究有参考价值. 相似文献
12.
G. Colò 《Physics of Particles and Nuclei》2008,39(2):286-305
Accurate assessment of the value of the incompressibility coefficient, K
∞, of symmetric nuclear matter, which is directly related to the curvature of the equation of state (EOS), is needed to extend
our knowledge of the EOS in the vicinity of the saturation point. We review the current status of K
∞ as determined from experimental data on isoscalar giant monopole and dipole resonances (compression modes) in nuclei by employing
the microscopic theory based on the Random Phase Approximation (RPA). The importance of full self-consistent calculations
is emphasized. In recent years, a comparision between RPA calculations based on either non-relativistic effective interactions
or relativistic Lagrangians has been pursued in great detail. It has been pointed out that these two types of models embed
different ansatz for the density dependence of the symmetry energy. This fact has consequences on the extraction of the nuclear
incompressibility, as it is discussed. The comparison with other ways of extracting K
∞ from experimental data is highlighted.
The text was submitted by the author in English. 相似文献
13.
The pressure-volume-temperature (P-V-T) equation of state (EOS), isothermal bulk modulus, and thermal expansivity of CaF2 with cubic fluorite-type structure are investigated using the constant temperature and pressure shell model molecular dynamics (MD) method with effective pair potentials which consist of the Coulomb, dispersion, and repulsion interaction. It was shown that MD simulation is very successful in accurately reproducing the measured volumes of the CaF2 over a wide range of pressures. The simulated P-V data matched X-ray diffraction experimental results up to 9.5 GPa at 300 K. In addition, volume thermal-expansion coefficient and isothermal bulk modulus were also calculated and compared with available experimental data and the latest theoretical results at ambient condition. At extended temperature and pressure ranges, The P-V EOS under different isotherms at selected temperatures, T-V EOS under different isobars at selected pressures, thermal expansivity, and isothermal bulk modulus were predicted up to 1500 K and 10 GPa. The detailed knowledge of thermodynamic behavior and EOS at extreme conditions are of fundamental importance to the understanding of the physical properties of CaF2. 相似文献
14.
Cai Lingcang Chen Qifeng Gu Yunjun Zhang Ying Zhou Xianming Jing Fuqian 《中国科学G辑(英文版)》2005,48(2):695-705
Hugoniot curves and shock temperatures of gas helium with initial temperature 293 K and three initial pressures 0.6, 1.2,
and 5.0 MPa were measured up to 15000 K using a two-stage light-gas gun and transient radiation pyrometer. It was found that
the calculated Hugoniot EOS of gas helium at the same initial pressure using Saha equation with Debye-Hückel correction was
in good agreement with the experimental data. The curve of the calculated shock wave velocity with the particle velocity of
gas helium which is shocked from the initial pressure 5 MPa and temperature 293 K, i.e., theD ≈u relation,D=C
0+λu (u<10 km/s, λ=1.32) in a low pressure region, is approximately parallel with the fittedD ≈u (λ=1.36) of liquid helium from the experimental data of Nellis et al. Our calculations show that the Hugoniot parameter λ
is independent of the initial density p{in0}. TheD≈u curves of gas helium will transfer to another one and approach a limiting value of compression when their temperature elevates
to about 18000 K and the ionization degree of the shocked gas helium reaches 10−3. 相似文献
15.
CAI Lingcang CHEN Qifeng GU Yunjun ZHANG Ying ZHOU Xianming & JING Fuqian Laboratory for Shock Wave Detonation Physics Research Institute of Fluid Physics Mianyang China 《中国科学G辑(英文版)》2005,48(6):695-705
Helium, hydrogen, and their isotopes are the simplest monoatomic and diatomic molecules. It is relatively easy to describe their properties using the basic principles of quantum mechanics. In condensed matter physics, hydrogen and helium serve as the models for the condensed matter properties at extreme conditions so that both experi- mental and theoretical physicists pay much attention to the study of their properties[1], especially the insulator-metal transition of hydrogen[2]. The aim to st… 相似文献
16.
Xueyang Yu 《高压研究》2013,33(1):19-28
Equation of state (EOS) of liquid Fe–17 wt%Si has been investigated at a temperature of 1773 K and pressures up to 12 GPa by the sink/float technique using composite spheres. The EOS of liquid Fe–17 wt%Si, in the form of the second order Birch–Murnaghan equation, produces K 0T=68±2 GPa when K′0T=4.0. Considering the effect of temperature and pressure on K 0T, extrapolation of this EOS to Earth's outer core conditions reveals that the addition of Si to liquid Fe decreases its density ρ and increases its compressional wave velocity V P , indicating that Si is a possible light element candidate in the outer core. The possible existence of Si in the cores of other planetary bodies is also discussed. 相似文献
17.
In this paper we have established the equation of state (EOS) for liquids. The EOS was established for hard-sphere (HS) fluid
along with Lennard–Jones (LJ) fluid incorporating perturbation techniques. The calculations are based on suitable axiomatic
functional forms for surface tension S
m
(r), r ≥ d/2 with intermolecular separation r, as a variable, and m is an arbitrary real number (pole). The results for βP/ρ from the present EOS thus obtained are compared with Percus-Yevick (PY), scaled particle theory (SPT), and Carnahan–Starling
(CS). In addition, we have found a simple EOS for the HS fluid in the region which represents the simulation data accurately. 相似文献
18.
Abstract We present an analytical equation of state (EOS) for solids using the bulk Grüneisenparameter γ. This EOS is applied to experimental V(p. T)-data of polycarbonate below the glass temperature, measured in a piston-cylinder apparatus up to 300 MPa. Bulk modulus K, the product K · α (α = thermal expansion coefficient) and the Grüneisenparameter γ are determined directly from the data as well as from a fit of the equation of state V(p.T) to the data. The fit with our EOS is better than the one with the empirical Tait-equation which is often used for polymeric materials. 相似文献
19.
20.
An equation of state (EOS) recently proposed for nanomaterials is discussed critically. Different possible forms of the EOS are discussed with their correlations. We have considered 20 nanomaterials for this purpose, viz. CdSe, Rb3C60, carbon nanotube, γ-Fe2O3, ε-Fe (hexagonal iron), MgO, γ-Al2O3 (67 nm), α-Fe2O3, α-Fe (filled nanotube), TiO2 (anatase ), 3C-SiC (30 nm), TiO2 (rutile phase), Zr0.1Ti0.9O2, γ-Si3N4, Ni-filled MWCNT, Fe-filled MWCNT, CeO2 (cubic fluorite phase and orthorhombic phase), germanium (49 nm), GaN (wurtzite phase) and SnO2 (rutile phase) (14 nm). It is found that the change in the form of EOS does not improve the results. This demonstrates the validity of the EOS proposed for nanomaterials. The EOS is also used to study the effect of temperature on compression of Ni (20 nm). It is found that there is small shift in isotherm due to increase in the temperature. The results have been found to present a good agreement with the available experimental data. 相似文献