Interaction between excitons in 3D and 2D laser-excited semiconductors

Analytical expressions of the exciton-exciton interaction in 3D and 2D laser-excited semiconductors are approximately derived in rather easy-to-handle forms which enable us to study in detail their dependences on the exciton momenta, the momentum transferred between two excitons and the electron-hole mass ratio.We would like to thank Prof. Nguyen Van Hieu and Prof. Dao Vong Due for their support given to us in the research of highly excited media.     

Conjectures on the character degrees of the harada-norton simple group HN

We classify the radical subgroups and chains of the Harada-Norton simple group HN and verify the Alperin weight conjecture and the refined Dade conjecture due to Uno for the group. This implies the Isaacs-Navarro and Dade reductive conjectures for the group. This work was supported in part by the Marsden Fund of New Zealand via grant #9144/3368248.     

A flexible and high-performance bidirectional optical amplifier with all optical gain control using ASE noise path through multi-port circulators

We report a flexible all-optical gain controlled bidirectional optical amplifier. The device achieves constant gain and low noise figure over a large input power range. Moreover, the device removes Rayleigh backscattered light and amplifier noise.     

Improvement of polyacrylate coating by filling modified nano-TiO2

Nano-TiO₂ is modified by a method, by which nano-TiO₂ first reacts with silane coupling agent WD-70 with double bond group which subsequently copolymerizes with methyl methacrylate and butyl acrylate to produce a thin polymer shell on the nanoparticles. The modified nanoparticles have stable organophilicity. They are applied to polyacrylate coating and performances of the coating are measured by different methods. The modification of nano-TiO₂ particles can improve their dispersibility in coating, enhance hardness of coating and reduce water absorption and permeability of polyacrylate coating. The mechanism has been analyzed in this paper.     

The Khler-Einstein metric for some Hartogs domains over symmetric domains

We study the complete Kahler-Einstein metric of a Hartogs domainΩbuilt on an irreducible bounded symmetric domainΩ, using a power Nμof the generic norm ofΩ.The generating function of the Kahler-Einstein metric satisfies a complex Monge-Ampere equation with a boundary condition. The domainΩis in general not homogeneous, but it has a subgroup of automorphisms, the orbits of which are parameterized by X∈[0,1[. This allows us to reduce the Monge-Ampere equation to an ordinary differential equation with a limit condition. This equation can be explicitly solved for a special valueμ0 ofμ.. We work out the details for the two exceptional symmetric domains. The special valueμ0 seems also to be significant for the properties of other invariant metrics like the Bergman metric; a conjecture is stated, which is proved for the exceptional domains.     

Electronic properties of the single-domain Li/Si(001) surface

Received: 14 October 1996/Accepted: 17 December 1996     

Synthesis of new dibenzo nitrogen-oxygen donor macrocycles containing two amide groups

Four new nitrogen-oxygen, dibenzo macrocyclic ligands containing two amide groups have been prepared by combining a dibenzo-containing diamidodialdehyde with an appropriate diamine followed by reduction of the intermediate bis Schiff-base. The starting dibenzo-containing diamidodialdehyde was prepared by treating 2 equivalents of salicylaldehyde with a bis(α-chloroamide).     

视觉极限衬比测试仪设计

本文介绍了人眼视觉极限衬比测试仪的原理、设计方法、功能及主要参数.其主要原理是在主光路和辅助光路中分别置一偏振片,其偏振方向相互垂直.旋转组合光路中的检偏镜,即可得到可供观察用的变衬比鉴别率图象.文章指出,使用这种仪器检测人眼视觉衬比的良好结果表明,新仪器研制是成功的.