排序方式: 共有38条查询结果,搜索用时 15 毫秒
31.
32.
本文运用数值模拟方法解耦合薛定谔方程,研究了常规势阱中的局部畸变对多个玻色-爱因斯坦凝聚(BEC)孤子的演化及相互作用特性的影响,发现势阱的局部畸变对BEC孤子的演化及相互作用的影依赖于畸变的强度和畸变的性质,与常规势阱的幅度、BEC孤子系统的参数及初始条件有密切的关系。 相似文献
33.
34.
An ultrathin wide-band planar metamaterial absorber based on a fractal frequency selective surface and resistive film 下载免费PDF全文
We propose an ultrathin wide-band metamaterial absorber (MA) based on a Minkowski (MIK) fractal frequency selective surface and resistive film. This absorber consists of a periodic arrangement of dielectric substrates sandwiched with an MIK fractal loop structure electric resonator and a resistive film. The finite element method is used to simulate and analyze the absorption of the MA. Compared with the MA-backed copper film, the designed MA-backed resistive film exhibits an absorption of 90% at a frequency region of 2 GHz-20 GHz. The power loss density distribution of the MA is further illustrated to explain the mechanism of the proposed MA. Simulated absorptions at different incidence cases indicate that this absorber is polarization-insensitive and wide-angled. Finally, further simulated results indicate that the surface resistance of the resistive film and the dielectric constant of the substrate can affect the absorbing property of the MA. This absorber may be used in many military fields. 相似文献
35.
阐述了新型电流变液体汽车减振器——电流变阀外置的双筒液力汽车减振器的工作原理 ,建立了它的理论模型 .描述了新型电流变液体汽车减振器阻尼力与电场之间的关系 .减振器的示功试验证明了理论分析的正确性 .本文以试验数据为依据 ,采用矩阵理论 ,用 MATLAB软件对电流变液体减振器的外特性进行了反求 ,得出了电流变液体减振器外特性对试验数据的最佳拟合曲线及公式 ,为汽车电流变液体减振器半主动悬架的设计奠定了基础 .具有重要的指导意义 . 相似文献
36.
酞菁钴/铁纳米填充母粒的制备及其稳定性 总被引:2,自引:0,他引:2
采用有机/无机原位复合技术,将酞菁钴(CoPc)的DMF溶液与Fe(CO)5混合、加热回流制备出稳定的、规则球形的、平均粒径为1.4μm的酞菁钴/铁纳米填充母粒。其内部为10~15nm的μ-Fe填充,外部为厚50~150nm的酞菁钴层包覆。纳米填充母粒的填实密度为3.664g/cm3,比饱和磁化强度为76.3Am2/kg,矫顽力为4.15kA/m。纳米填充母粒的热稳定性高于150℃,与甲基硅油组成的磁流变液有良好的抗沉降性。 相似文献
37.
38.
A wideband metamaterial absorber based on a magnetic resonator loaded with lumped resistors 下载免费PDF全文
<正>A wideband metamaterial absorber(MA) based on a magnetic resonator loaded with lumped resistors is presented. It is composed of a one-dimensional periodic array of double U-shaped structured magnetic resonators loaded with lumped resistors,a dielectric substrate,and a metal plate.We simulated,fabricated,measured,and analyzed the MA. The experimental results show that the reflectance(S11) is below -10 dB at normal incidence in the frequency range of 7.7 GHz-18 GHz,and the peak value is about—20 dB.Simulated power loss density distributions indicate that wideband absorption of the MA is mainly attributable to the lumped resistors in the magnetic resonator.Further investigations indicate that the distance between two unit cells along the magnetic field direction significantly influences the performance of the MA. 相似文献