Minimal surfaces in a complex hyperquadric Q 2

In this paper, we discuss minimal surfaces in a complex hyperquadric Q ₂. It is proved that every minimal surface of constant Kähler angle in Q ₂ is holomorphic, anti-holomorphic, or totally real. We also prove that minimal two-spheres in Q ₂ with either constant curvature or parallel second fundamental form must be totally geodesic.     

Totally real conformal minimal tori in the hyperquadric Q 2

Our purpose is to study the minimal tori in the hyperquadric Q ₂. Firstly, we obtain a necessary and sufficient condition for the minimal surface in Qn which is also minimal in CP ⁿ⁺¹. Next, we show that this kind of minimal surface (neither holomorphic nor anti-holomorphic) with constant curvature in Q ₂ is part of a flat totally real torus. Finally, we prove that totally real minimal flat tori in Q ₂ must be totally geodesic, and we classify all the totally geodesic closed surfaces in Q ₂.     

Rational first integrals for periodic systems

In this paper, by using the Floquet’s theory, we present some criteria for non-existence and partial existence of rational first integrals for periodic systems in a neighborhood of the constant solution.     

A general regularized gradient-projection method for solving equilibrium and constrained convex minimization problems

In this article, we provide a general iterative method for solving an equilibrium and a constrained convex minimization problem. By using the idea of regularized gradient-projection algorithm (RGPA), we find a common element, which is also a solution of a variational inequality problem. Then the strong convergence theorems are obtained under suitable conditions.     

临界电流磁矢量分析法在YBCO线圈上的验证

高温超导磁体临界电流磁矢量分析法准确地预测了BSCCO高温超导磁体的临界电流,为了进一步验证该方法预测YBCO高温超导磁体临界电流的准确性,文中作者用9.3m二代高温超导YBCO带材绕制了一个内径为70mm,外径为100mm,共35匝的单饼,测试了单饼5-15匝,15-25匝,25-35匝和5-35匝在77K下的临界电流,并用磁矢量分析法进行了仿真分析。通过对比发现,仿真分析和实验结果的误差在5%左右,最大误差是6.75%,最小误差是4.77%,验证了磁矢量分析法在预测YBCO高温超导磁体临界电流时的准确性。     

Polarization properties of subwavelength metallic gratings in visible light band

Optical polarization properties of aluminum, gold and aluminum/gold subwavelength metallic gratings (SWMGs) are investigated numerically in the visible light band. Their performance as polarizing beam splitters are simulated with RCWA for varied metallic materials, grating depth and incident angle. Metallic waveguide theory is applied to explain the performance difference between Au and Al grating. A new type of Al/Au bimetallic is also investigated numerically for potential applications. PACS 42.79.Dj; 42.81.Gs; 73.20.Mf     

CO2激光热熔法除冰的研究

介绍了CO2激光在高压线除冰中的实验研究情况.由于直接热融法除冰效率较低,提出了激光热融加上冰块自身重力脱落法除冰的实验方案.利用功率为35 W的CO2激光照射冰块与绝缘子的接触面,降低其粘结力以致整体脱落从而达到除冰的目的,测得除去1 kg冰需要90kJ的能量,耗时26 min.     

KDP晶体折射率非均匀性检测系统

基于正交偏振干涉法,建立了KDP晶体折射率非均匀性的检测系统,并可实现晶体相位失谐角的间接检测.波前检测系统实现了测试光偏振态的精密控制与切换,采用波长调谐相移的方法去除了测试过程中参考面倾斜引入的误差,优化了抗振动相移算法,提高了波前测试的测量准确度及重复性.通过折射率非均匀性分析算法的设计,解决了晶体厚度变化引入的误差等.小口径晶体元件的测试结果表明系统的折射率非均匀性检测准确度(均方根值)优于10-6.