Ultrabroadband Infrared Luminescence and Optical Amplification in Bismuth-Doped Germanosilicate Glass

This letter reports the ultrabroadband infrared luminescence from 1000- to 1700-nm wavelength range and demonstrate optical amplification at the second optical communication window in a novel bismuth-doped germanosilicate glass. The full-width at half-maximum of the luminescence is about 300 nm and the optical gain is larger than 1.37 within the wavelength region from 1272 to 1348 nm with pump power 0.97 W. This material could be useful to fabricate ultrabroadband optical fiber amplifiers.     

半行波半导体激光放大器超短光脉冲响应及开关特性的实验研究

本文对半行波半导体激光放大器的脉冲响应及开关特性进行了实验研究。脉宽为27ps,重复频率为1GHz的超短光脉冲串通过放大器后脉冲无展宽。当对放大器的注入电流进行调制时,放大器可起到高速光开关的作用。     

高斯光束光学系统的合成

本文在输入、输出空间折射率不相等情况下,分析了对应于不同变换要求的几种高斯光束光学系统的分解方法,阐明各种分解形式的意义。同时,讨论了当给定系统输入、输出空间高斯光束参数时,系统如何实现的问题。     

增益与光强的相关系数对光栅外腔半导体激光器稳态特性的影响

本文引入增益与光强的相关系数h,建立了光栅外腔半导体激光器的稳态模型。数值计算结果表明:激光器的其它参数必须与h相匹配,才能使激光输出的稳定区增大,且可在一定波长范围内进行选频,保证很好的单模性。     

同时含有稀土元素La Ce Pr Nd的材料的电子探针定量分析方法

研制了稀土六硼化物单晶LaB_6、CeB_6、PrB_6和NdB_6电子探针分析标样。根据X-射线峰位表和实测的特征X-射线谱,考察分析了La、Ce、Pr和Nd元素谱线之间的干扰情况,发现分析谱线PrLα_1受到L_αLβ_1线严重的干扰。以混合稀土金属为试样,采用扣除谱线重叠强度的背底非对称测量等方法对L_n、Ce、Pr和Nd进行了电子探针定量分析,其结果与荧光X-射线光谱分析结果符合较好。     

Creation of Ghost Illusions Using Wave Dynamics in Metamaterials

The creation of wave‐dynamic illusion functionality is of great interest to various scientific communities because it can potentially transform an actual perception into the pre‐controlled perception, thus empowering unprecedented applications in the advanced‐material science, camouflage, cloaking, optical and/or microwave cognition, and defense security. By using the space transformation theory and engineering capability of metamaterials, a functional “ghost” illusion device, which is capable of creating multiple virtual ghost images of the original object's position under the illumination of electromagnetic waves, is proposed and realized. The scattering signature of the object is thus ghosted and perceived as multiple ghost targets with different geometries and compositions. The ghost‐illusion material, which is being inhomogeneous and anisotropic, is realized using thousands of varying unit cells working at non‐resonance. The experimental demonstration of the ghost illusion validates the theory of scattering metamorphosis and opens a novel avenue to the wave‐dynamic illusion, cognitive deception, manipulate strange light (or matter) behaviors, and design novel optical and microwave devices.     

SER‐Based Relay Selection for Two‐Way Relaying with Physical Layer Network Coding

To enhance the symbol error rate (SER) performance of the two‐way relay channels with physical layer network coding, this letter proposes a relay selection scheme, in which the relay with the maximal minimum distance between different points in its constellation among all relays is selected to assist two‐way transmissions. We give the closed‐form expression of minimum distance for binary phase‐shift keying and quadrature phase‐shift keying. Additionally, we design a low‐complexity method for higher‐order modulations based on look‐up tables. Simulation results show that the proposed scheme improves the SER performance for two‐way relay networks.     

二手房中介管理系统设计研究

针对中介公司对二手房管理的需要,二手房中介管理系统将提供给中介公司一个良好的二手房管理平台.开发主要包括后台Sqlserver数据库的建立和维护以及使用JDBC与java GUI的平台搭建.本文将基于jdbc的介绍、二手房中介管理的需求分析以及二手房中介管理的设计.     

Enhancing the Photovoltaic Performance of Ladder-Type Heteroheptacene-based Nonfullerene Acceptors by Incorporating Halogen Atoms on Their Ending Groups

Ending group halogenation is an effective strategy for modulating the energy levels, bandgaps, and intermolecular interactions of nonfullerene acceptors. Understanding the influence of different halogen atoms on the acceptor properties is of great importance for designing high-performance nonfullerene acceptors. Here, three acceptor–donor–acceptor (A-D-A) type nonfullerene acceptors (M5, M6, and M7), which are constructed by using a ladder-type heteroheptacene core without the traditional sp³ carbon-bonded side chains as the electron-rich core, and 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile without or with halogen atoms as the ending groups. The nonfullerene acceptors with chlorinated (M6) and brominated (M7) ending groups exhibit broadened absorption spectra, down-shifted energy levels, and enhanced molecular ordering compared to the counterpart without any halogenated ending groups (M5). Among the nonfullerene acceptors, M6 has the strongest intermolecular π π interaction with its shortest π π interaction distance and the longest coherent length which are beneficial for enhancing the charge transport and therefore boosting the photovoltaic performance. An excellent power conversion efficiency of 15.45% is achieved for the best-performing polymer solar cell based on M6. These results suggest that the halogenated ending groups are essential for high-performance heteroheptacene-based nonfullerene acceptors considering their simultaneous enhancements in both the light-harvesting and the charge transport.