Effective Traffic Grooming Algorithms in SONET/WDM Ring Networks

Much work has focused on traffic grooming in SONET/WDM ring networks. Previous work has considered many aspects of traffic grooming, including minimizing the number of ADMs, minimizing the number of wavelengths, considering different traffic models, using different network architectures, incorporating switching capability and so on. In this work, we study traffic grooming in unidirectional ring networks with no switching capability under both uniform traffic and non-uniform traffic models to reduce electronic multiplexing costs. Based on the clustering notion, we derive a general and tighter lower bound for the number of ADMs required in traffic grooming under the uniform all-to-all traffic model. This bound reduces to special cases obtained in previous work. We also derive general, tighter, and closed form lower bounds for the number of ADMs required under two non-uniform traffic models: the distance-dependent traffic model and the non-uniform symmetric traffic model. Cost-effective multi-phase algorithms that exploit traffic characteristics are then designed and studied to efficiently groom traffic streams under different traffic models. Our numerical and simulation results show that the proposed multi-phase algorithms outperform existing traffic grooming algorithms by using a fewer number of ADMs. Our algorithms in several cases also achieve the lower bounds derived.     

Mechanochemically initiated polymerisations. 12. Spectral and thermal characterisation of some products obtained by vibratory milling of benzene and pyridine

Vibratory milling is used to open the aromatic ring of compounds such as benzene and pyridine and this is followed by concatenation of the structural units. The products obtained form both the soluble fractions in methanol, i.e. dimethylformamide and the insoluble fraction, the latter being found in the prevalent amount. Analysis of the soluble fractions by infrared spectroscopy (i.r.) and pyrolysis-gas chromatography (p.-g.c.) conforms their linear structure of the polyenic type with some short crosslinkings and a great sensitivity to the action of atmospheric oxygen.     

Simulating three-dimensional vortex motion by a vortex blob method

A three-dimensional vortex blob method was applied to calculate several vortex motions: the deformation of pseudo-elliptic vortex rings, the jet issuing from the pseudo-elliptic nozzle into flow of uniform velocity, the unsteady separated flow around a circular disk with an angle of attack, and the interaction of several vortex rings which approximately reproduced the Kolmogorov spectrum. In the first three cases, the viscous diffusion of vorticity was included. The pseudo-elliptic vortex rings experienced axis switching and split into a few deformed vortex rings. Rolling-up vortices in the pseudo-elliptic jet had a symmetric arrangement in the minor-axis plane and an antisymmetric arrangement in the major-axis plane in the developing region; further downstream, the vortices were arranged antisymmetrically in both planes. The wake behind the disk normal to the main flow reproduced the spiral and columnar modes of instability. A problem in the three-dimensional vortex method is that vorticity tends to diverge at a stage of evolution of the vortex motions. An approximate method of avoiding the divergence of vorticity is proposed.     

有限环计算的数字式神经网络方法

本文提出一种用于有限环算术的数字式神比网络方法。它采用非对称的数字式神经网络结构，在整个矢量空间上具有唯一的平衡点，因而不存在计算误差。这种方法保持了神经网络的高度并行结构，能够实时完成有限环上的模运算。它还被应用于中国余数定理的实现。     

A theorem on neutral delay systems

It is known that the stabilization of neutral delay differential tems requires first the stabilization of the difference operator or D-operator. In case all delays in the system are commensurable, necessary and sufficient conditions for the existence of suitable derivative feedback for the stabilization of the D-operator have been known for some time [14]. In this note we derive a result in the case of noncommensurable delays analogous to the known results for the commensurable delay case.     

活塞环结构设计研究

应用弯曲理论，将活塞环处理为平面曲杆，考虑轴向力和初始曲率对活塞环变形的影响，分析计算了活塞环装配后的变形和内力，从而设计出活塞环在自由状态下的理论廓形，该设计精度较高，对活塞环的结构设计具有一定的实用性。     

同轴环形磁铁磁作用力计算的等效磁荷法

以电磁学中的假想磁荷理论为基础，建立了内外同轴的两环形永久磁铁相互作用力的力学模型，并在此基础上，推证出了两环形磁铁磁作用力的数学模型，从而在不做任何假设及简化的条件下，建立了内外同轴的两环形磁体承载力的计算公式．应用该计算公式能够使两环形磁体相互作用的各机械量具有很高的计算精度．该公式的推证建立方法对分析和建立其它形式的磁体相互作用力的计算公式具有普遍意义．因此，计算磁体磁作用力的等效磁行法是研究永久磁体承载力的一个新的有效途径．     

高能气体压裂试验效果分析

本阐述了高能气体压裂的原理，通过5口井的试验对比，分析了试验井的效果和用高能气体发生器压裂对套管及水泥环的影响，试验结果表明，用高能气体发生器压裂对解除近井地带污染，改善油层渗流条件有明显效果。     

高压直流输电环形电极埋深特性分析

为了优化直流接地极的设计,以双圆环接地极为例,采用经典镜像法分析了电极在均匀和非均匀土壤中埋设深度变化对跨步电压、溢流密度和接地电阻等运行参数的影响;针对标准双环或三环电极,提出了一种同心非等深立体布置的设计思路。计算分析和仿真结果表明:1)电极埋深宜控制为2~4m,最大不应>4m;2)水平分层土壤中,标准多环电极的内环埋深对于系统运行参数的影响不大,实际工程中采用非等深立体布置设计在技术上是可行的,且相对等深布置经济性更佳。     

钢球磨煤机减速机轴封漏油治理

对乌海热电厂二期2×200 MW燃煤机组钢球磨煤机减速机轴封漏油问题进行了分析,原因为减速机油位过高、密封轴套有刮痕、轴封没有装设挡油密封以及骨架密封油唇磨损.结合实际情况采用降低减速机油位、加装迷宫式密封及挡油密封环等措施对其进行技术改造,改造后钢球磨煤机减速机轴封未再发生漏油现象,改造效果良好.