丝阵Z箍缩早期消融等离子体动力学的二维数值模拟研究     

黄俊  孙顺凯  肖德龙  丁宁  宁成  张扬  薛创 《海洋学报》2010,32(9):6351-6361

采用理想磁流体力学模型,给出合理的二维(r, θ)质量注入边界条件,对丝阵Z箍缩早期消融等离子体的动力学过程进行了二维(r, θ)数值模拟研究,得到消融等离子体各参量以及磁场的二维时空分布.模拟结果表明,消融等离子体的运动包括四个主要阶段:首先向轴漂移,然后在轴线处滞止并形成先驱等离子体柱,随后先驱等离子体柱被压缩,最后缓慢膨胀.计算了不同丝阵半径和丝间距情况下消融等离子体到轴速度以及消融质量占丝阵总质量的份额,它们的变化规律与实验结果基本符合.通过  相似文献   

(2+1)维 Korteweg-de Vries 方程的传播孤子及混沌行为     

吴红玉  马松华  方建平 《海洋学报》2010,32(10):6719-6724

利用一个投射方程和变量分离法,得到了(2+1)维 Korteweg-de Vries (KdV) 方程的新显式精确解.根据得到的孤立波解,构造出 KdV 方程的传播孤子结构. 利用一个新的混沌系统研究了孤子的混沌行为.  相似文献   

折射/谐衍射红外双波段成像光谱仪系统研究     

刘英  孙强  卢振武  曲锋  吴宏圣  李淳 《海洋学报》2010,32(10):6980-6987

为了获取足够的目标信息,充分利用中波红外和长波红外的光谱信息,建立了谐衍射中、长波红外超光谱成像系统.利用谐衍射元件独特的色散特性,将谐衍射透镜应用于中、长波红外超光谱成像系统中,使系统在中波红外3.7—4.8 μm和长波红外8—12 μm的2个红外大气窗口内获取数百个光谱图像.设计结果表明,中波红外波段,在18对线/mm处光学系统的调制传递函数(MTF)大于0.55;长波红外波段,在13对线/mm处光学系统的MTF大于0.5;光学系统的衍射环绕能,在中波红外波段30 μm半径范围内大于85%,在长波红外  相似文献   

ATON型Hall推力器缓冲区预电离问题研究     

刘辉  吴勃英  鄂鹏  段萍 《海洋学报》2010,32(10):7203-7208

ATON是20世纪90年代新提出的一种Hall推力器设计方案,其中的缓冲区是ATON新采用的一种结构.本文对缓冲区的作用进行分析,在此基础上提出了采用附加电源提高缓冲区预电离率的方法.并采用PIC(Particle-in-cell)粒子模拟方法对这种设计方式的等离子体分布进行数值模拟.结果表明,通过增加缓冲区内的附加电压,能够有效地提高缓冲区预电离率.  相似文献   

原子掺杂对单元材料结晶能力的影响     

彭坤  明辰  叶祥熙  张文献  庄军  宁西京 《海洋学报》2010,32(10):7245-7251

2009年我们建立了一个凝结势模型用以预测材料形成单晶体的能力,表明单元体材料(Ni,Al,Cu,Ar,Mg)的结晶能力随凝结势的增大而单调增强.本文将凝结势模型应用于二元材料体系,并结合分子动力学模拟研究了6% Al原子掺杂对于Ni单晶材料结晶能力的影响.模拟结果发现,Al元素的掺杂会大大减弱Ni单晶的结晶能力,在此基础上提出了二元材料体系凝结势的定义,表明凝结势模型可广泛应用于预测二元体材料的结晶能力.  相似文献   

Mechanism and enhancement of photoluminescence from silicon nanocrystals implanted in SiO₂ matrix     

吴志永  刘克新  任晓堂 《海洋学报(英文版)》2010,29(9)

Photoluminescence (PL) spectra of Si nanocrystals (NCs) prepared by 130 keV Si ions implantation onto SiO₂ matrix were investigated as a function of annealing temperature and implanted ion dose. PL spectra consist of two PL peaks, originated from smaller Si NCs due to quantum confinement effect (QCE) and the interface states located at the surface of larger Si NCs. The evolution of number of dangling bonds (DBs) on Si NCs was also investigated. For hydrogen-passivated samples, a monotonic increase in PL peak intensity with the dose of implanted Si ions up to 3× 10¹⁷ ions /cm² is observed. The number of DBs on individual Si NC, the interaction between DBs at the surface of neighbouring Si NCs and their effects on the efficiency of PL are discussed.  相似文献   

boldmath Investigation of inter-molecular hydrogen bonding in the binary mixture (acetone + water) by concentration dependent Raman study and ab initio calculations     

欧阳顺利  吴楠楠  孙成林  刘靖尧  里佐威  高淑琴 《海洋学报(英文版)》2010,29(9)

This paper reports that vibrational spectroscopic analysis on hydrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311+G(d,p) basis set. Changes in wavenumber position and linewidth (fullwidth at half maximum) have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.  相似文献   

Extension of high-order harmonics and generation of an isolated attosecond pulse in the chirped laser field     

伍杰  翟振  刘学深 《海洋学报(英文版)》2010,29(9)

This paper theoretically investigates the high-order harmonic generation cutoff extension using intense few-cycle linearly chirped laser pulses. It shows that the cutoff of the harmonic can be extended remarkably by optimising the chirping parameters. The time-frequency characteristics of high-order harmonics with different chirping parameters are analysed by means of wavelet transform of the dipole acceleration. It also gives out the classical three-step model pictures of electron. By superposing a properly selected range of the harmonic spectrum, it obtains an isolated 65as pulse.  相似文献   

Structural, curvature and electronic properties of Rh adsorption on armchair single-walled carbon nanotube     

杨培芳  吴锋民  滕波涛  刘莎  蒋健中 《海洋学报(英文版)》2010,29(9)

This paper systematically studies the rolling effects of the (n, n) single-wall carbon nanotubes (SWCNT) with different curvatures on Rh adsorption behaviours by using density functional theory. The outside charge densities of SWCNTs are found to be higher than those inside, and the differences decrease with the increase of the tube radius. This electronic property led to the discovery that the outside adsorption energies are higher than the inside ones, and that the differences are reduced with the increase of the tube radius. Partial density of states and charge density difference indicate that these strong interactions induce electron transfer between Rh atoms and SWCNTs.  相似文献   

Investigation on performance of all optical buffer with large dynamical delay time based on cascaded double loop optical buffers     

王拥军  吴重庆  忻向军  余贶琭  张晓磊 《海洋学报(英文版)》2010,29(9)

Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dynamical delay time is carried out based on cascaded double loop optical buffers (DLOBs). It is found that pulse distortion can be restrained by a negative optical control mode when the optical packet is in the loop. Noise analysis indicates that it is feasible to realise a large variable delay range by cascaded DLOBs. These conclusions are validated by the experiment system with 4-stage cascaded DLOBs. Both the theoretical simulations and the experimental results indicate that a large delay range of 1--9999 times the basic delay unit and a fine granularity of 25 ns can be achieved by the cascaded DLOBs. The performance of the cascaded DLOBs is suitable for the all optical networks.  相似文献