共查询到20条相似文献,搜索用时 238 毫秒
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研究了两分量旋转玻色爱因斯坦凝聚体在谐振子势与高斯势的联合势阱中的基态特性和自旋纹理。通过托马斯-费米近似得到每组分凝聚体在相混合态时密度分布首次形成中心洞的临界旋转角频率,并根据旋转角频率与临界旋转角频率的关系,给出了两分量凝聚体的三种不同的基态密度分布:两个都是盘、一个是盘和另一个是环、两个都是环。对于相分离的情况,针对两分量粒子数严重不平衡的凝聚体分别作托马斯费米近似,解析地给出了两分量凝聚体的两种对称基态密度分布。同时研究了凝聚体在两分量的界面处形成的两种赝自旋纹理,它们分别是巨斯格明子和同轴双环斯格明子。 相似文献
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采用水热法在氧化锌晶种修饰的衬底上生长氧化锌纳米棒,利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)系统地分析了晶种分布状态对氧化锌纳米棒排列的影响.SEM结果表明随着晶种密度的增大,氧化锌纳米棒从排列无序向具有高度取向的紧密有序纳米棒阵列转变,反映纳米棒端面垂直生长优化;XRD表征显示,随着晶种密度的增大,(002)峰增强,(110)峰减弱,即端面衍射增强,侧面衍射减弱,与SEM结果相对应.同时在生长的氧化锌纳米棒中存在链状和花状的簇结构,分析表明这些簇结构与晶种在衬底上的特殊分布状态有关. 相似文献
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使用粒子模拟程序对30 fs超短超强激光在均匀与抛物型两种密度分布等离子体中的传输, 以及在稳定传输状态下尾场的电子注入与加速形成的电子能谱进行了模拟与分析. 固定入射激光束斑尺寸, 在(0.4-2)×1019/cm3等离子体密度范围, 对比分析了归一化峰值强度从1-6范围的激光脉冲在上述两种密度分布等离子 体中传输时激光束斑尺寸的演化, 结果表明抛物型分布的等离子体密度通道能够对超短超强脉冲实现良好的导引, 有利于高能电子加速. 对于较高密度情况,即使在均匀等离子体中依靠相对论自聚 焦等机制也可以实现良好的自导引传输,有利于实验简化以及产生更大电量的加速电子. 相似文献
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从量子力学的基本原理出发,采用指数差分方法,利用Matlab,模拟了入射不同势场后的粒子密度分布情况.结果表明,改变势场分布及粒子入射方式,粒子密度分布会产生显著变化.该模拟适用面广,可应用于不同的物理问题. 相似文献
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Olin Jack G. Chen Kun-Mu 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1975,3(3):97-101
A new diagnostic method based on the excitation of thermal resonances using an electroacoustic probe has been developed to determine the electron density profile and other plasma parameters of a cylindrical warm-plasma column. A coaxial electroacoustic probe is used to excite and detect the dipole and thermal resonances as the plasma density is varied. The electron density profile is expressed functionally in terms of unknown profile parameters. The profile and other parameters of the plasma column are then determined numerically based on some theoretical formulas and experimental results. 相似文献
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Lennox R Carney K Maldonado-Basilio R Philippe S Bradley AL Landais P 《Optics letters》2011,36(13):2521-2523
We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is used to control the device noise figure, with a minimum value of 5 dB observed at a gain of 15 dB for an optimum carrier density profile. The opposite carrier density profile results in an increase of the power saturation by 3 dB. 相似文献
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ZHOU Yan DENG Zhongchao YAO Lianghua XIAO Zhenggui DING Xuantong LIU Yong WANG Enyao 《核工业西南物理研究院年报(英文版)》2004,(1):14-16
Several high performance tokamak operation regimes have been achieved experimentally in the experiments with the peaked density profiles. The regimes include the improved Ohmic confinement in ASDEX, the pellet enhanced performance mode in Alcator-C, and the super-shot mode in TFTR. In these regimes, peaked core density profiles are always existent, and almost always go with the internal transport barriers, these barriers generally produced by sheared radial electric field. In addition to enhance confinement, the peaked density profile is also needed for the optimized fusion reaction rate and alpha heating power in tokamak plasma, and combined peaked density profile and peaked temperature profile, would make the ignition condition easy obtained. It is desirable to seek and analyze the density profile control schemes that effectively lead to density profile peaking in particle transports experimental investigation. 相似文献
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In this paper the density profile behaviour and the particle confinement operation regime on HL-1M have been studied under the pellet injection (PI), supersonic molecular beam injection (SMBI), gas puffing (GP) and lower hybrid current drive experimental situations. The relationships between density profile, particle confinement time and edge safe factor have been explored. The density profile, which is measured by six-channel far-infrared ray laser interferometer has been analysed by using the peaking coefficient calculation code. Changes of the outward and inward diffusion velocities before and after the peaking of the central density profile have been calculated using the global particle balance equations. The particle confinement operation regimes have been discussed. The peaking density profile can be easily obtained under the condition of efficient fuelling. In ohmic discharges, confinement time increases as the peaking density profile factor rises, and is saturated at a critical value related to the fuelling efficiency. The particle confinement time of SMBI lies between the values of GP and PI, and its value is about 3-5 times of the energy confinement time. 相似文献
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冯贤平 《核聚变与等离子体物理》1988,(2)
本文在临界密度区域内激光场趋于零的假设下,系统地研究了由强激光辐照非均匀等离子体引起临界密度变陡的现象,给出了较为精确、完备的描述等离子体密度结构的各种参数和等离子体密度的坪台结构。 相似文献
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The generation of large amplitude (MG) quasi-stationary magnetic fields in a laser produced plasma with density profile steepening in the domain of the critical point is considered. The spatial structure of the generated magnetic fields in this domain is obtained. It is shown that the density profile steepening causes a significant enhancement of the generated magnetic fields with respect to a linear profile. The saturation level of the generated magnetic fields is evaluated. 相似文献
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G.D. Tsakiris D.A. Boyd D.A. Hammer A.W. Trivelpiece R.C. Davidson 《Physics letters. A》1979,70(1):23-26
The spectrum of the synchrotron radiation emitted from the University of Maryland mirror confined nonneutral plasma is measured during the decay of the pulsed magnetic field and used to obtain the energy distribution ?(γ) and electron density profile ne0(r). One result is that the electron density profile evolves from a relatively thin E-layer to a broad profile with density build-up on axis. 相似文献
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S. Sokołowski 《Molecular physics》2013,111(4):859-869
We investigate the density profile of a fluid in contact with a wall. Our analysis is based on the summation of the virial expansion for the local density and the resulting integral equation for the density profile involves the two particle direct correlation function of a non-uniform fluid. 相似文献
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We report the density depth profile of an as-deposited Ni film and density profile for the same film after controlled electrochemical
corrosion by chloride ions, measured by unpolarized neutron reflectometry. The neutron reflectometry measurement of the film
after corrosion shows density degradation along the thickness of the film. The density profile as a function of depth, maps
the growth of pitting and void networks due to corrosion. The profile after corrosion shows an interesting peaking nature.
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