偏分复用系统信道串扰的理论模型及消除方案

建立了偏分复用(PDM)系统中信道串扰的数学模型,并提出了消除该串扰的方案,即用解复用端一路光信号的射频(RF)功率作为反馈信号以监测光信号在链路中偏振态的变化和在接收端的串扰情况,用粒子群优化(PSO)算法作为逻辑控制单元的算法,控制偏振控制器以消除信道间的串扰。数值仿真了RF功率与信道串扰大小之间的关系,并在2×50Gb/s偏分复用-差分正交移相键控(PDM-DQPSK)传输系统平台上仿真验证了消除串扰方案的效果。结果表明该方案能够大幅降低系统误码率,改善系统性能。     

盐水-水的小孔周期性泄流实验与分析

通过对盐水-水小孔周期性泄流的实验研究,对孔径为1.32 mm的8种不同孔长进行测量,得出周期正比于孔长的1.1±0.1次方,同时对孔径为1.32 mm孔长为113.00 mm条件下的内筒液面跟踪记录得出实验曲线为指数形式,与理论分析符合得较好.     

全湿法制备聚合物电致发光器件

利用全溶液方法制备了聚合物电致发光器件并研究了器件的性能。器件的所有膜层,包括发光层和上电极层均采用溶液湿法获得,完全摒弃了真空蒸镀工艺。利用二次溶剂掺杂获得的PEDOT∶PSS聚合物薄膜的电导率达到608.7 S/cm。在240 nm的厚度时,聚合物电极膜层的面电阻约为68 Ω/□; 当膜层厚度为1 μm时,薄膜的面电阻可低于16 Ω/□。采用溶液滴涂方法制备的高电导PEDOT∶PSS聚合物薄膜作为上电极替代通常所用的铝电极,所制备的聚合物发光器件的开启电压约为4 V。     

疏松载流螺线管轴线上磁场的分布研究

疏松载流螺线管轴线上磁场实验的设计可以测量螺线管轴线不同位置上的轴向磁场和径向磁场,实验结果与数值计算结果吻合。另外,从该实验测量结果发现疏松型螺线管轴线上的轴向磁场与螺距呈近似线性关系。这些工作不仅可作为大学物理实验课的选做内容,还可以为设计基于测量磁场的位移和应力传感器提供依据。     

Structural analysis and crystal-field calculations of Nd^3＋ in Gdx Lu1-x TaO4（x = 0.85） polycrytalline

The crystal structural parameters of Nd 3+-doped rare earth orthotantalate Gd x Lu 1 x TaO 4(x = 0.85) are determined by applying the Rietveld refinement to its X-ray diffraction,and its emission and excitation spectra at 77 K are analysed.The relativistic model of ab initio self-consistent DV-Xα method,which is applied to the cluster NdO 8 in Gd x Lu 1 x TaO 4,and the effective Hamiltonian model are used to investigate its spin-orbit and crystal-field parameters.The free-ions and crystal-field parameters are fitted to the experimental energy levels at 77 K with a root-mean-square deviation of 14.92 cm 1.According to the crystal-field calculations,96 levels of Nd 3+ are assigned.Finally,the fitting results of free-ions and crystal-field parameters are compared with those already reported for Nd 3+:YAlO 3.The results indicate that the free-ion parameters are similar to those of the Nd3+ in Gdx Lu1-x TaO4 and YAlO 3 hosts,and the crystal-field interaction of Nd3+ in Gdx Lu1-x TaO4 is stronger than that in YAlO 3.     

Polymer Light-Emitting Diode Using Conductive Polymer as the Anode Layer

The analysis based on series equivalent circuit indicates that the resistance of electrode layers is the major factor limiting the current density of polymer light-emitting diodes （PLEDs） at higher voltages. The conductivity of 790 S/cm for the PEDOT：PSS film is achieved by secondary doping. At a thickness of 240 nm, the sheet resistance of the polymer layer is 51 Ω/sq, which is comparable to that of lTO films. The current density and luminance of the PLEDs with the polymer anode layer is higher than the ITO anode device, suggesting that it is feasible to replace ITO anode with a highly conductive polymer in PLEDs.     

Progress in AMS Measurement of 182Hf at CIAE

Accelerator mass spectrometry （AMS） is one of the most promising methods to detect minute amounts of 182Hf. However, the sensitivity of 5×10^-11 for ^182Hf/180Hf obtained previously by the AMS method at China Institute of Atomic Energy （CIAE） cannot meet the requirement of some applications. We present some new improvements of measurement method for AMS measurement of 182Hf at the CIAE HI？13 tandem accelerator system. As a result, a sensitivity of 1.0×10^-11 for 182Hf/180Hf is achieved.     

Modulational Instability and Variable Separation Solution for a Generalized （2＋1）-Dimensional Hirota Equation

It is demonstrated by the linear modulational instability analysis that a generalized （2＋1）-dimensional Hirota equation is modulationally stable. Then, a B？cklund transformation （BT） is obtained by means of the truncated Painlevé approach. Using the BT, the model is transformed to a system of equations, which finally leads to a special variable separation solution with arbitrary functions.     

高频脉冲管制冷机连管影响研究

针对高频脉冲管制冷机实际应用中引入的连管进行了研究,实验结果表明加长连管导致性能下降的关键因素在于流动阻力损失,在选取时应尽量减少连管长度,在长度无法改变的情况下,可以选用较大直径的连管以减少流动损失,另外运行在略低的频率也会对制冷性能下降有所改善。     

Electron-phonon Coupling in Gallium-Doped Germanium

The electronic structure, lattice dynamics, and electron-phonon coupling of gallium-doped germanium are inves- tigated using ab initio supercell methods. Our results indicate the superconducting transition in gallium-doped germanium can be explained within a standard phonon mediated mechanism. The contribution of acoustic modes to the coupling constant A almost entirely comes from Ga related modes, and - 25% to λ. The calculated coupling constant is 0.35 and the corresponding transition temperature is 0.44 K for the gallium-doped germanium with 6.25% gallium content using Coulomb pseudopotential μ^＊ = 0.1, in agreement well with the experimental data.