Heading towards an advanced signalling system for multimedia,multiparty services in broadband ISDN

Introduction of the broadband integrated services digital network (B-ISDN) will enable network users to make use of advanced multimedia, multiparty services. With this aim in view, RACE II project R2044, MAGIC, is investigating long-term signalling requirements, architecture and protocols for B-ISDN. New service concepts are being developed in MAGIC which will provide more flexibility when compared to narrowband ISDN (N-ISDN). The service requirements and other signalling requirements, such as the separation between call and associated connections at the network-node interface, are used to determine the distribution of functions over the network. The signalling protocols which are used to exchange the signalling information are subsequently developed. These signalling protocols are simulated to prove the performance and the feasibility of call handling concepts     

“镍”催化酰氯和有机锡试剂交叉偶联反应的研究

镍络合物催化酰氯与有机锡试剂交叉偶联合成有机酮的反应,其反应选择性强,反应彻底,转化率高,工艺简单。在有机锡过量的情况下,对不同催化剂的催化活性和包括投料比,反应温度,反应时间,反应溶剂等反应条件进行了考察。     

管外上升R－113流体的沸腾换热试验

详细介绍了Ｒ－１１３流体管外上升流动的沸腾换热试验，包括试验台架、流量计和温度测量的修正，以及试验数据。拟合的换热关系式为ｑ＝５２８（Ｔｗ─Ｔｓ）１．３３。     

An efficient numerical approach, for determining the dispersioncharacteristics of dual-mode elliptical-core optical fibers

Based on vectorial formulations which combine the surface integral equation method and the finite-element method, a novel numerical approach is proposed for calculating the dispersion coefficients of dual-mode elliptical-core fibers with arbitrary refractive index profiles. By differentiating the original formulations involving the propagation constant β and the guided mode fields H_x and H_y once and twice with respect to the normalized frequency V, the new formulations for {dβ/dV, dH_x/dV, dH_y/dV} and for {d²β/dV², d² H_x/dV², d²H_y/dV² } are obtained respectively. Once {β, H_x, H_y } is solved through the eigenvalue procedure which dominates the computing time, only a few matrix manipulations are required to obtain {dβ/dV, dH_x/dV, dH_y/dV} and {d²β/dV², d²H_x/dV² , d²H_y/dV²}. Some numerical examples are examined to see the influence of different refractive index distributions with dips on the dispersions of the four nondegenerate LP ₁₁ modes for elliptical-core fibers     

Experimental and theoretical studies on a distributed temperaturesensor based on Brillouin scattering

Results are reported from recent research on the use of the Brillouin gain/loss mechanism for distributed sensing. A theoretical model of the interaction of the pulsed and CW beams is described and compared with experiments. Results from a system with a 51 km sensing length are presented. We finally investigate issues related to the variation within the sensing fiber of the polarizations of the two beams     

COIL中BHP浓度对发生O_2(~1△)的影响

本文实验研究了BHP的浓度对产生O2（1△）的影响。实验结果表明：当BHP浓度大于3.5M时，Cl2利用率以及O2（1△）的产率将不依赖于BHP浓度的变化而变化，同时，实验结果表明，使用低浓度的BHP对COIL的操作是可行的。     

Simulation study of peak junction temperature and power limitationof AlGaAs/GaAs HBTs under pulsed and CW operation

The authors have used a 3-D transmission-line matrix (TLM) modeling method to study the junction temperature distribution and power limitation of device geometries with multiple embedded heat sources. Peak values of the junction temperature against the dissipated power density under both pulsed and CW operation are presented for a typical power AlGaAs/GaAs HBT structure. These data should facilitate the rapid determination of junction temperature for a given output power, which is of paramount importance in power device design     

AN improved method of optimization for electrical machines

Methods of optimizing the design of electrical machines are discussed. The augmented Lagrangian multiplier method is described, and an algorithm for this method is introduced. The method is compared with the more familiar exterior penalty function method using, as an example, the cost optimization of permanent magnetic variable-speed drive motors. The improved method is shown to be superior, both in its ability to reach an optimum consistently and in the number of required iterations     

用数采器对空压机进行状态监测预报

通过几个典型事例的分析、判断和处理，介绍了该厂怎样利用９１ｌ型数采器对２Ｄ１２—１００／８型空压机运行状态进行监测，以预报早期故障，为设备检修提供指导．