Experimental Research on Erbium-doped Superfluorescent Fiber Source

The effects of the variations in fiber length, fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs). The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated. By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port, the pump power dependent on MWS becomes independent of pumped EDF length. This is a novel phenomenon that hasn‘t been reported up to now,and should be helpful to SFS fabrication and theory analysis. By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ～20 channels (from 1542nm to 1559nm) is got. The MWFS has a channel spacing of ～0. 8 nm which satisfies ITUstandard. The intensity fluctuation among channels is less than 0.5dB,and the extinction ratio of all channels is above 14dB. This kind of MWFS should be useful to wavelength division multiplexing systems.     

Updated semi‐discretization method for periodic delay‐differential equations with discrete delay

An updated version of the semi‐discretization method is presented for periodic systems with a single discrete time delay. The delayed term is approximated as a weighted sum of two neighbouring discrete delayed state values and the transition matrix over a single period is determined. Stability charts are constructed for the damped and delayed Mathieu equation for different time‐period/time‐delay ratios. The convergence of the method is investigated by examples. Stability charts are constructed for 1 and 2 degree of freedom milling models. The codes of the algorithm are also attached in the appendix. Copyright © 2004 John Wiley & Sons, Ltd.     

Robust State Feedback Control Through Actuators With Generalized Sector Nonlinearities And Saturation

In control systems, actuators often have nonlinear characteristics that can not be neglected. For linear systems driven by actuators satisfying the generalized sector condition, a robust state feedback controller synthesis method is proposed to achieve the ultimate boundedness control. The method is based on the linear matrix inequality approach and is easy to apply. As an important special case of the generalized sector condition, the saturation characteristic of actuators is discussed separately, and non‐conservative results are obtained.     

热处理对Ti-25V-15Cr-2Al-2Mo-0.2C合金组织稳定性的影响

研究了热处理对Ti-25V-15Cr-2A1-2Mo-0.2C阻燃β钛合金组织稳定性的影响。结果表明，高温固溶并直接时效处理导致合金β基体上析出较多的α相沉淀，尤其在随后的热暴露组织中形成了恶化合金塑性的连续晶界α膜。然而，若在时效前再进行一次低温固溶处理则可明显减少α相的析出数量，合金的热稳定性因此而得到显著改善。     

岭澳核电工程38m平台边坡处理

岭澳核电重件道路施工中所遇到的38m的观景平台在大亚湾核电站占有重要地位,在工程施工中发现边坡坡体陡峭,无法达到规范规定的稳定要求,故采取了加固措施。采用抗滑稳定计算的分析方法,对边坡加固的必要性及实施加固后的稳定性进行了分析。     

Global complete observability and output-to-state stability imply the existence of a globally convergent observer

We consider systems which are globally completely observable and output-to-state stable. The former property guarantees the existence of coordinates such that the dynamics can be expressed in observability form. The latter property guarantees the existence of a state norm observer and therefore the possibility of bounding any continuous state functions. Both properties allow to conceptually build an observer from an approximation of an exponentially attractive invariant manifold in the space of the system state and an output driven dynamic extension. The proposed observer provides convergence to zero of the estimation error within the domain of definition of the solutions. The work of A. Astolfi is partly supported by the Leverhulme Trust.     

CPAM的分子参数对页岩抑制性的影响

通过合成的一系列具有不同分子量的聚丙烯酰胺的阳离子化制得具有不同分子参数的阳离子聚丙烯酰胺（ＣＰＡＭ）。经评价实验就分子参数对页岩抑制性的影响进行研究     

Stabilization of inter-area and/or oscillatory modes in large-scale power system by voltage impedance power system (VIPS) apparatus based on decentralized control scheme

New technologies such as power electronics have made it possible to change continuously the impedance of a power system not only to control power flow but also to enhance stability. A power system incorporating a variable impedance apparatus such as a variable series capacitor (VSrC) and high-speed phase shifter (HSPS) is called VIPS (Variable Impedance Power System) by the authors. This paper proposes a novel control method of VIPS apparatus such as VSrC and HSPS installed at an interconnecting point for stabilizing inter-area unstable and/or oscillatory modes. The proposed design method of the control system is a kind of hierarchical decentralized control method of a large-scale power system based on a Lyapunov function. Under the proposed control scheme, each subsystem can be stabilized independently by local controllers such as AVR, speed governor and PSS, and then the whole interconnected system can be stabilized by VIPS apparatus taking into account interactions between subsystems. The effectiveness and robustness of the VIPS apparatus control are shown by numerical examples with model systems including a large-scale power system.     

高速冷带轧机垂直自激振动稳定性分析的数值计算方法

本文在充分考虑轧机垂直振动过程中辊缝非线性的基础上，利用轧制理论方程和机械振动理论中的能量判据，给出了更精确的分析高速冷轧机垂直自激振动稳定性的数值计算方法。     

自发参量下转换制备双光子纠缠态在量子信息学中的应用

叙述了自发参量下转换制备双光子纠缠态技术的发展历程、技术原理以及在量子信息学中的应用，并介绍了国内这一领域的进展。