Interferometric noise limitations in fibre-amplifier cascades

Phase-induced intensity noise from weak multiple reflectors is evaluated theoretically and experimentally in amplifier cascades without isolators. Rayleigh backscattering alone significantly limits the number of amplifiers in the span. Theory and experiment agree closely for a six-amplifier cascade.<>     

悬浮型速溶PHPAM堵水剂及其堵水技术

本文介绍了以悬浮型速溶PHPAM为基础研制的低温油井堵水剂,讨论了影响堵水剂交联时间和成胶粘度的因素,制定了移动式弹性隔板堵水工艺并成功地应用于二连油田蒙古林砾岩油藏的油井堵水。该堵剂适用于30—60℃油井,交联时间可控、配制简便、快速、施工周期短。     

The high jugular bulb: report of five cases and a review of the literature

The jugular bulb varies widely in position and dimensions. A high jugular bulb is not an uncommon finding in temporal bones. Besides our five cases with different clinical manifestations, we review 52 cases diagnosed clinically and published previously in the English literature. The high jugular bulb occurs more often on the right temporal bone. Certain pathologic conditions, such as an abnormal bone formation, an aberrant sinusojugular system, or decreased pneumatization of the mastoid bone, may predispose an individual to its occurrence. Most people with this anatomical variation remain asymptomatic. However, various otologic problems and symptoms may be attributed to this condition. A high resolution computed tomography scan is the most convenient diagnostic tool at present. Law projection plain mastoid radiography may reveal a high jugular bulb in certain cases, providing a preoperative warning to an otologic surgeon. An exploratory tympanotomy is not suggested for those with a high jugular bulb with a conductive hearing loss, while jugular vein ligation has been reported to have good results in alleviating intractable pulsatile tinnitus. For most asymptomatic patients, regular long-term follow-up is recommended.     

感光性材料在火箭发动机上的应用

主要介绍感光性材料的制备及其在火箭发动机包覆层中的应用，即用感光性树脂通过紫外光辐射固化，以简化现有的包覆工艺，并提高包覆层的性能。     

Variations of physical properties in pellets containing alumina/carbon powder mixtures during reduction and nitridation

Surface area and porosity of pellets containing alumina/carbon powder mixtures during reduction and nitridation were determined. The experimental results indicated that surface area and porosity of solid samples were decreased by increasing the reaction temperature, grain size, forming pressure and the amount of catalyst. Increasing the molar ratio of C/Al₂O₃ and gas flow rate could decrease the surface area and increase the porosity of the solid sample.     

Link set sizing for networks supporting SMDS

To size networks that support switched multimegabit data service (SMDS), one must determine how much additional capacity is needed and where it is needed so as to minimize the total capacity augmentation cost. Two combinatorial optimization problem formulations are considered and compared for their relative applicability and complexity. A solution procedure based on Lagrangean relaxation is proposed for one of the formulations. In computational experiments, the proposed algorithm determines solutions that are within a few percent of an optimal solution in minutes of CPU time for networks with 10-26 nodes. The proposed algorithm is compared with a most congested first (MCF) heuristic. For the test networks, it achieves up to 152% improvement in the total cost over the MCF heuristic     

氦氢混合工质单级GM型脉管制冷特性实验研究

针对80K温区，在一台单级GM型脉管制冷机中进行了氦氢二元混合工质的实验研究。实验结果表明，采用一定组分的氦氢混合工质可以提高脉管制冷机的制冷性能。     

Kerr介质中"耦合双原子-单模光场"模型的反聚束效应

利用全量子理论,研究了在Kerr介质中,耦合二能级双原子与单模光场相互作用过程的反聚束效应,着重讨论了Kerr介质对场的二阶相干度的影响,并揭示了初始场强及原子间耦合系数的变化与场的二阶相干度的关系。