共查询到20条相似文献,搜索用时 296 毫秒
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为分析冷冻靶丸外部温度场,应用ANSYS软件对ICF空心微球靶的热传递进行了有限元分析。建立了单元传热的几何物理模型,靶丸微球呈空间均匀分布,计算区域由三个同心球壳组成,分别为液体层、靶丸壳层以及氦气层,氦气层厚度为球壳层厚度的7倍。模型左右两边界设为绝热边界条件,采用智能自动划分网格,设定参数为3,单元类型为三角形。模拟表明,在靶丸工作温度为24 K的情况下,为保持靶丸气泡受力平衡,自洽得到靶丸内部温度梯度为14.02 K/cm,以此求解出所施加的外部温度场为7.758 K/cm。将计算值与现有的实验结果进行了比较,模拟结果与国外实验值(8.2 K/cm)吻合得较好。 相似文献
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WEN Cheng-wei SHEN Chun-lei YU Ming-ming XIA Li-dong WANG Kai LI Hai-rong 《光谱学与光谱分析》2018,38(1):73-76
氢同位素的定量分析与监测在能源与环境领域都有着重要的意义。激光拉曼光谱由于其可以无损分析氢同位素分子,已经成为一种重要的方法,在国际热核聚变实验反应堆(ITER)和美国萨凡纳河工厂得到了广泛应用。利用高压充气装置得到了惯性约束聚变(ICF)高压靶丸,并对靶丸内气体进行原位拉曼光谱测量,通过对高压下氘氚混合气体的拉曼光谱进行分析得到了靶丸内气体的成分比例,验证了靶丸充气工艺参数。实验表明,在CCD的积分时间延长到1 min时,氘(DD),氘氚(DT)和氚(TT)的测量精度可以达到1%,同时对不同时刻靶丸内气体组分的拉曼光谱进行测量,实验结果表明在氘氚渗透和氚衰变两者共同作用下,靶丸内总气体压力随时间不断下降,但是气体组成基本不发生变化。 相似文献
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惯性约束聚变(ICF)冷冻靶中氘氘(D2)、氘氚(DT)等燃料冰层在靶丸中的分布由靶丸所处的温度场决定。在氘氘冷冻靶中,垂直温度梯度引起的气-液界面张力梯度可以抵消重力作用,使氘氘液体在靶丸内均匀分布;然后在氘氘的三相点附近缓慢降温,可以实现燃料冰层的均化。在氘氘冷冻靶均化实验系统上,采用温度梯度结合制冷速率与制冷过程控制的方法,实现了1mm直径、30μm壁厚的辉光放电聚合物(GDP)靶丸中氘氘冰层的均化,对背光阴影图像中亮环位置进行分析表明:氘氘冰层的平均厚度为185.56μm,均匀度为80.2%,模数-功率谱曲线中模数2~100对应的内表面粗糙度为2.26μm。 相似文献
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为了精密检测靶丸壳层厚度及其分布数据,开展了靶丸壳层厚度及其分布的白光反射光谱测量技术研究。介绍了靶丸壳层的白光反射光谱及其光谱数据处理方法(极值法、峰值拟合法、干涉级次校正法等)的基本原理,搭建了基于白光反射光谱的精密回转轴系测量装置;开展了GDP靶丸壳层厚度及其分布的白光反射光谱测量、数据处理和可靠性验证实验,获得了靶丸壳层厚度圆周分布曲线。结果表明,基于峰值拟合法和干涉级次校正的白光反射光谱技术可实现靶丸壳层厚度及其分布的准确测量,其测量误差小于0.1 μm。 相似文献
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低温冷冻靶是实现惯性约束聚变(inertial confinement fusion,ICF)的关键部件之一.低温靶靶丸内杂质气体的去除程度和效率对低温靶燃料冰层的在线制备具有重要意义.依据低温靶物理对冰层杂质含量的设计要求,在计算靶丸内杂质气体最大允许分压的基础上,建立了靶丸内气体在微米级充气管内流动的抽空流洗模型.模拟研究了不同微管尺度及结构、温度对靶丸内杂质气体抽空流洗效率的影响规律,获得了靶丸充气微管的最佳管型设计方案.基于最佳管型设计,优化得到了具有最高抽空流洗效率的抽空时间与流洗次数组合策略. 相似文献
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一种改进的低温靶系统,包括低温靶体,超冷气流发生器及其控制器,气泡沸腾状态监控仪和阳极化铝冲击波同轴探测器,已经成功地引入基于二级轻气炮的低温冲击压缩实验.详细地剖析了其中的几种专用部件,讨论了相应的实验方法.最后,为了验证该系统,将液体CO2单质样品一次冲击压缩到22~60GPa(220~600 kbar)得到的Hugoniot数据与早先的实验结果进行比较.结果表明,改进后的低温靶系统结构合理、简单,操作安全,功能较多,成本较低.同时,利用本系统获得的液体CO2样品的冲击压缩数据精度高,重复一致性更好.很容易推广到凝点在300~77K范围内其它简单分子物质的冲击压缩实验.甚至有可能用于液氦(4K)或液氢(20K)温区的冲击压缩实验. 相似文献
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在惯性约束核聚变中,决定点火成功与否的关键因素在于靶丸内燃料冰层的均匀性,而影响靶丸内燃料冰层均匀性的主要因素为靶丸温度场均匀性.为了提升靶丸温度场均匀性,采用定向红外辅助均化装置实现对靶丸表面温度场的局部调控.在定向红外装置的运行过程中,红外光空间分布误差会影响到靶丸温度场的调控效果.建立了定向红外光线追踪与温度场计算耦合的数值模型,并与实验进行对照分析,确定了数值模型良好的计算精度.采用三维的冷冻靶物理模型,研究了不同形式的定向红外光空间分布误差对靶丸温度场的影响规律.结果表明:光轴偏心对靶丸温度场均匀性的影响最为剧烈,光带间距变化的影响次之,光带宽度的变化对靶丸温度场均匀性的影响最小.在实验中应当尽可能避免南北两侧光带光轴的偏心,从而保证靶丸表面温度均匀性,进而可以保证靶丸内燃料冰层的均匀性. 相似文献
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Pakharukov Yu. V. Shabiev F. K. Mavrinskii V. V. Safargaliev R. F. Voronin V. V. 《JETP Letters》2019,109(9):615-619
A wavy structure of the surface of graphene nanoparticles on a hydrocarbon substrate has been obtained. It has been shown that the wavy surface is the manifestation of the Kelvin-Helmholtz instability at the interface between liquid paraffin and graphene suspension with the inhomogeneity length λ = 250 nm. The manifestation of such wavy structures is due primarily to van der Waals forces.
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Yu. V. Sanochkin 《Technical Physics》2003,48(5):546-551
It is shown that, along with gravity waves, surface and internal waves caused by van der Waals forces may exist in a liquid
with a horizontal free surface. A dispersion relation is found by using the stepwise approximation for the coefficients of
a wave equation derived for these waves. The surface waves are similar to surface gravity waves in dispersion and amplitude
distribution but differ in frequency by several orders of magnitude. Another sequence of roots in the spectrum corresponds
to internal van der Waals waves that have an upper frequency bound and the dispersion law typical of a multimode waveguide. 相似文献
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L. Genzel 《Physics letters. A》1978,65(4):371-373
It has been shown before [1] that two large molecular systems having low-lying giant dipole vibrations may interact through strong long-range forces. This paper deals with the influence of a polar medium with Debye dispersion on this interaction between the molecules. It is shown that besides the normal van der Waals attraction also repulsion can occur, but this only in a limited range of the molecular eigenfrequencies just above the characteristics relaxation frequency τ?1 of the medium. 相似文献
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Details of the problem of “vertical” transitions between discrete levels of 2D electrons on the surface of liquid (solid) dielectrics in the presence of a gas over this surface (their own vapors or artificially produced combinations such as solid hydrogen-gaseous helium) are discussed. The structure of the interaction of an electron with a gaseous medium, where the so-called scattering length appears to depend on the gas density, is determined. The role of Van der Waals forces, which attract gas atoms to the dielectric surface, is shown. A notion of quasi-2D electron bound states on gas atoms is introduced. The experimental data concerning the effect of the gas on the frequencies of optical transitions for 2D electrons over the surface of solid hydrogen are discussed using this information. 相似文献
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The present study has theoretically investigated the combined torsional buckling of double-walled carbon nanotubes (DWCNTs) with axial load in the multi-field coupled condition. The effects of torsion, axial load, thermal-electrical change, surrounding elastic medium and the Van der Waals forces are all taken into consideration. The governing equation of buckling for CNTs subjected to thermo-electro-mechanical loadings has been established based on an elastic shell model of continuum mechanics. Reasonable s... 相似文献
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V. D. Urlin 《Journal of Experimental and Theoretical Physics》2013,117(5):833-845
A new form of the semiempirical equation of state proposed for the liquid phase of hydrogen isotopes is based on the assumption that its structure is formed by cells some of which contain hydrogen molecules and others contain hydrogen atoms. The values of parameters in the equations of state of the solid (molecular and atomic) phases as well as of the liquid phase of hydrogen isotopes (protium and deuterium) are determined. Phase diagrams, shock adiabats, isentropes, isotherms, and the electrical conductivity of compressed hydrogen are calculated. Comparison of the results of calculations with available experimental data in a wide pressure range demonstrates satisfactory coincidence. 相似文献
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V. B. Shikin 《JETP Letters》2000,72(5):260-263
The development of mechanical instability of a neutral fluid film (liquid helium or hydrogen) under inversion conditions (it does not lie on a solid substrate but hangs from a ceiling) is discussed. Critical parameters of such an instability and the character of surface reconstruction under the action of van der Waals forces, bubble pressure, and gravitational forces are determined. The interrelation with the well-known Frenkel problem of a drop on a solid substrate is pointed out. An electrostatic mechanism is proposed for the stimulation of instability of a thin helium film. This mechanism is promising for the problem of superfluid helium leakage. 相似文献
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《Physica A》2006,369(2):895-904
The information regarding the structure of a single protein is encoded in the network of interacting amino acids considered as nodes. If any two atoms from two different amino acids (nodes) are within higher cut-off distance of London-van der Waals forces, the amino acids are considered to be linked or connected. Several atoms of any amino acids in a protein may be within the above prescribed distance of several atoms of another amino acid resulting in possible multiple links between them. These multiple links are the basis of the weight of the connectivity in a protein network. Each protein has been considered as a weighted and an unweighted network of amino acids. A total of forty nine protein structures that covers the three branches of life on earth has been analyzed and several network properties have been studied. The probability degree and strength distributions of network connectivity have been obtained. It has been observed that the average strength of amino acid node depends on its degree. The results show that the average clustering coefficient of weighted network is less than that of unweighted network. It implies that the topological clustering is generated by edges with low weights. The power-law behavior of clustering coefficients of weighted and unweighted networks as a function of degree indicates that they have signatures of hierarchy. It has also been observed that the network is of assortative type. 相似文献