超光滑基片表面散射的数值研究

以一阶微分散射理论为基础,从理论和模拟两个方面对超光滑基片表面的散射电磁场进行了数值研究.分析了s偏振光和p偏振光的微分散射随入射角和散射角的分布情况.研究发现,当入射角较大时,p偏振光在某个散射方向的微分散射为0,而无论入射角和散射角如何变化,s偏振光的微分散射均大于0.当用光散射法对超光滑基片进行表面测试时,相对于...     

光捕获和光操控研究进展

光捕获和光操控是一种通过光镊、倏逝波、光泳或光热等对微纳尺度颗粒、生物大分子和细胞等微小物体进行非接触、无损伤捕获和操控的方法和技术.详细归纳和总结了国际上在光捕获和光操控方面的研究进展和最新动态,分析了其今后的研究发展方向.     

同轴电介质-金属-电介质结构表面等离激元色散研究

从平面电介质-金属薄膜-电介质对称结构中表面等离激元的色散方程出发,建立模型推导得到了同轴电介质-金属薄膜-电介质结构中表面等离激元的色散方程,在这种结构中各阶模式都发生了分裂,形成了高折射率高损耗和低折射率低损耗的两种模式,该模型为理解同轴电介质-金属薄膜-电介质结构表面等离激元模式的传播提供了直观的图像。用色散方程计算了0.5～1.5μm波长范围内各阶模式的等效折射率以及传输损耗,并将该结果与有限元方法数值模拟得到的结果进行对比分析,分析表明,两者吻合得很好。并分析了计算结果以及色散方程的适用范围。     

壁面结构对非定常薄膜流动表面波特性的影响

采用VOF方法,在入口处引入周期扰动,对沿矩形结构底板下落的二维非定常薄膜流动进行直接数值模拟.计算结果表明,不同频率的外加周期扰动在流场中激发出不同波长的自由表面波.当壁面结构的波长与之相比较小时,由于壁面结构引起的静态波骑行在外加扰动形成的行进波上.若这两个波长相近,非线性效应将促进附近的表面波之间的合并.当薄膜无...     

推导粒子数态波函数的厄米多项式算符法

引入厄米多项式算符并用其正规乘积展开式推导出了粒子数态|n〉在坐标表象和动量表象下的波函数,并由此得出了坐标和动量本征态的福克(Fock)表示形式,这是一个简洁而全新的推导方法.     

Z箍缩丝阵负载区域的似稳态磁场分布

 将负载区域的电流（丝阵电流、阴极板电流、阳极板电流和回流柱电流）离散成电流线或电流面等电流微元,根据毕奥-萨伐尔定律,计算所有电流微元在指定场点的磁场,再通过叠加给出该点的总磁场。研究结果发现:在丝阵外围区域,仅由丝阵电流所产生的磁场偏离无限长直导线磁场公式的值,但全部电流所产生的总磁场与公式给出的值很接近。同时,研究了不同负载结构参数下的磁场分布,结果表明：增加丝根数有助于减小单根丝表面的局部磁场,改善丝阵外围磁场分布的均匀性。     

回旋速调管注-波互作用非线性理论研究

 利用自洽非线性理论对回旋速调管放大器中的电子注-波互作用进行了时域瞬态分析,建立了多腔回旋速调管非线性理论,给出了相应的电子运动方程和复数形式的互作用瞬态场方程。给出并分析了一支工作在TE01模Ka波段四腔回旋速调管注-波互作用的数值计算结果,当电子注电压为72.8 kV,电流为11.8 A,速度零散为5%时,可以得到335 kW的最大饱和功率输出,39.6%的电子效率及320 MHz的饱和带宽,与实验值相比较,二者较为吻合。     

Organic-inorganic hybrid superhydrophobic surfaces using methyltriethoxysilane and tetraethoxysilane sol-gel derived materials in emulsion

By applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) in organic siloxane modified polyacrylate emulsion (OSPA emulsion), we are able to demonstrate the potential for developing a sol-gel derived organic-inorganic hybrid emulsion for a superhydrophobic surface research. TEOS and MTES derived sol-gel moieties can be designed for a physical roughness and hydrophobic characteristic (Si-CH₃) of the hybrid superhydrophobic surface, while OSPA emulsion can be endowed for good film-forming property. The effect of formulation parameters on superhydrophobicity and film-forming property was analyzed. The water contact angle (WCA) on the sol-gel derived hybrid film is determined to be 156°, and the contact angle hysteresis is 5° by keeping the mole ratio of TEOS:MTES:C₂H₅OH:NH₃·H₂O:AMP-95 at 1:4:30:10:0.63 and the mass percentage of OSPA emulsion at 25%. The nanoparticle-based silica rough surface is observed as the mole ratio of MTES/TEOS at 4:1. The sol-gel derived organic-inorganic hybrid emulsion shows remarkable film-forming property when the mole ratio of MTES/TEOS reaches or exceeds 4:1. With the primer coating, the performance of superhydrophobic film achieve actual use standard. It reveals that this new procedure is an effective shortcut to obtain a superhydrophobic surface with potential applications.     

The fractional variational iteration method using He's polynomials

In this Letter, by introducing He's polynomials in the correct functional, we propose a new fractional variational iteration method to solve nonlinear time-fractional partial differential equations involving Jumarie's modified Riemann-Liouville derivative. Several examples have been solved to illustrate the proposed method is quite effective and convenient for solving kinds of nonlinear fractional order problems.     

The potential energy surface and chaos in 2D Hamiltonian systems

We provide a new insight into the relationship between the geometric property of the potential energy surface and chaotic behavior of 2D Hamiltonian dynamical systems, and give an indicator of chaos based on the geometric property of the potential energy surface by defining Mean Convex Index (MCI). We also discuss a model of unstable Hamiltonian in detail, and show our results in good agreement with HBLSL's (Horwitz, Ben Zion, Lewkowicz, Schiffer and Levitan) new Riemannian geometric criterion.