聚变实验堆真空室壳体成型残余应力分析

为了了解聚变实验堆真空室壳体表面残余应力的分布以及退火工艺对残余应力的影响,通过模拟分析和实验检测两种方式对不锈钢316LN冷压曲面和热压曲面残余应力进行研究,获得退火前后曲面表面残余应力的大小,得到冷压曲面和热压曲面残余应力的分布以及退火工艺对残余应力分布的影响。研究结果为分析成型工艺提供数据支撑,对中国聚变工程实验堆真空室的研究与制造具有重要意义。     

Ultra-fast grain boundary diffusion and its contribution to surface segregation on a martensitic steel. Experiments and modeling

Phosphorus surface segregation was measured by Auger Electron Spectroscopy on a 17-4 PH martensitic stainless steel at 450, 550 and 600 °C. Surface segregation was shown to be much faster than expected which was attributed to a high contribution of phosphorus diffusion along the former austenitic grain boundaries. A model of surface segregation was developed following the Darken–du Plessis approach and taking account of both bulk and grain boundary solute diffusion. The phosphorus grain boundary diffusion coefficient in 17-4 PH was estimated: D_GB^< = 6.2 10⁴ exp(? 157 kJ mol^? 1/RT)cm² s^? 1. It is found to be more than three orders of magnitude higher in 17-4 PH steel than in α-iron.     

光学薄膜诱导偏振像差对大数值孔径光学系统聚焦特性的影响

大数值孔径光学系统表面光线的入射角较大, 会导致薄膜的偏振分离, 诱发偏振像差, 影响光学系统的聚焦特性. 本文利用矢量光衍射理论, 建立了光学薄膜各参量与光学系统聚焦光场的模型. 利用该模型分析了线偏振光入射时, 光学薄膜对光学系统聚焦光斑的扰动. 在此基础上, 探讨了应用了不同约束条件下得到的光学薄膜对最终聚焦光场的影响, 确定了减小薄膜扰动光学系统光斑的设计方法, 即额外添加透射率差和位相差的约束条件, 并且适当增加位相差约束的权重. 利用该方法优化设计的薄膜, 相比于普通减反膜而言, 对系统聚焦光场中心强度的提升可达约12.5%.     

Representation of the category of tangles by Kontsevich's iterated integral

Applying Kontsevich's iterated integral for tangles, we get an isotopy invariant of tangles. We give a method to compute the integral of a tangle combinatorially from modified integrals of some simple tangles. We localize the integral by moving the end points of the tangle to an extreme configuration, and modify the integral so that it is convergent. By using a similar technique, we generalize Kontsevich's invariant to a framed tangle.     

Tight-binding method modelling of photonic crystal waveguides

We present here a tight-binding-like modelling of two-dimensional (2D) photonic crystals (PCs). Adopted from solid-state physics, the concept of generalized Wannier functions is used to construct a localized state basis that allows a parameter-free ab initio study of defects in PCs. We demonstrate here for a 2D triangular lattice of dielectric rods in air, the existence of this localized basis and the possibility to study large scale complex dielectric structures deviating from periodicity. Specific numerical simulations on a split waveguide embedded in this triangular lattice are performed, and they demonstrate the superiority of this method over plane wave based techniques.     

Core-level photoelectron study of indium chains on Si(1 1 1) at 10 K

High-resolution core-level data from the prototypical In/Si(1 1 1) system have been acquired at 10 K. An asymmetric tail in the In 4d spectra reveals a metallic character of the low temperature Si(1 1 1)8 × 2 phase confined to the inner indium rows. The decoupling of the one-dimensional inner indium chains from any metallic environment at ∼10 K suggests a possible Luttinger liquid behavior. At room temperature essentially a broadening of the spectral features is noticed, which appears compatible with a fluctuation scenario.     

Inducing anisotropy in bulk Nd-Fe-Co-Al-B nanocrystalline alloys by quenching in magnetic field

We have observed magnetic anisotropy in bulk Nd_55−xCo_xFe₃₀Al₁₀B₅ (x=10, 15 and 20) alloys prepared by copper mold suction casting method with a presence of external magnetic field (quenching field) μ₀H=0.25 T. By changing direction of the measuring field from perpendicular to parallel one in comparison with that of the quenching field, coercive force of the alloys slightly decreases while remanent magnetization and squareness of hysteresis loop increase more clearly. It is also found that the higher Co-concentration in the alloys the larger magnetic anisotropy is induced. The structure analyses manifest nanocrystalline particles embedded in residual amorphous matrix of the alloys. The size of the particles is in range of 10-30 nm and their crystalline phases consist of Nd₂(Fe,Co)₁₄B, Nd₃Co, Nd₃Al, NdAl₂ and Nd.     

不同应用条件下最佳绝缘子构型

绝缘子的沿面闪络制约着脉冲功率系统向高电压、大电流方向发展,总结了几种实际应用条件下的最佳绝缘子构型,并对不同角度下绝缘子表面的带电情况进行了分析。结果表明,表面电荷对不同绝缘子构型的性能起着至关重要的作用,需要根据不同的应用条件来开展实验研究以确定最佳的绝缘子构型。     

斑头雁不同组织氨基酸的组成和含量分析

采用高效液相色谱法对斑头雁卵、肌肉和羽毛中17种氨基酸进行了含量的测定,并分析其中必需氨基酸的含量,为斑头雁的保护和利用提供依据。结果表明,斑头雁的卵、腿肌、胸肌和羽毛中均含有17种氨基酸,必需氨基酸含量较高,配比合理,有较高的营养价值。