Operator-Based Robust Nonlinear Control for SISO and MIMO Nonlinear Systems With PI Hysteresis

In this paper, operator based robust nonlinear control for single-input single-output (SISO) and multi-input multi-output (MIMO) nonlinear uncertain systems preceded by generalized Prandtl-Ishlinskii (PI) hysteresis is considered respectively. In detail, by using operator based robust right coprime factorization approach, the control system design structures including feedforward and feedback controllers for both SISO and MIMO nonlinear uncertain systems are given, respectively. In which, the controller design includes the information of PI hysteresis and its inverse, and some sufficient conditions for the controllers in both SISO and MIMO systems should be satisfied are also derived respectively. Based on the proposed conditions, influence from hysteresis is rejected, the systems are robustly stable and output tracking performance can be realized. Finally, the effectiveness of the proposed method is confirmed by numerical simulations.      

A tool for tracing network data plane via SDN/OpenFlow

SDN provides an approach to create desired network forwarding plane by programming applications. For a large-scale SDN network comprised of multiple domains and running multiple controller applications, it is difficult to measure and diagnose the problems of flow tables in data plane. Tracing the forwarding path of SDN is one of effective way for data plane state measurement. Previously proposed methods for debugging SDN were applied to a single administrative domain. There is less effort to trace the flow entries of the data plane in large-scale multi-domain SDN networks. In this paper, we propose a method of software defined data plane tracing in large-scale multi-domain SDN networks. Our method can trace forwarding paths, and get the matched flow entries and other customized trace information. We present the designs compatible with OpenFlow 1.0 and 1.3 switches. The performance and deployment effect are evaluated by simulation test and analysis. It shows that our method has better performance than traditional IP traceroute, and its deployment at about 20% of AS nodes can enable 70% of AS paths to be traceable.     

Some Issues on Core‐Annulus and Cluster Models of Circulating Fluidized Bed Reactors

The one‐dimensional cluster model and the core‐annulus model are examined based on existing correlations. The core‐annulus model is found to give reasonable agreement with ozone decomposition data when the effective interphase mass transfer rate constant is equal to about 0.1 1/s, which is one order smaller than the reported values based on gas tracer tests. The prediction from the core‐annulus model that the reactor performance decreases with increasing the riser diameter is found to be inconsistent with limited experimental data The one‐dimensional cluster model predicts that a riser reactor performs very close to the pseudo‐homogeneous plug flow reactor because of the high mass transfer rate between the cluster and the dilute phase. The improvement of model predictions lies in the better characterization of the cluster shape, size and the mass transfer rate between the cluster and the dilute phases.     

工业废料加固土的试验研究

利用炉渣和粉煤灰等废渣、并掺入适量水泥或石灰等胶凝剂来加固土壤，可以节约工程造价、改善环境。分别以水泥、石灰、水泥 石灰混合料加固由粉煤灰、粘土、细砂、淤泥．炉渣以不同配比组成的三种复合土，每种拌合物以相同的加水量分别制备3组试件．自然条件下养护3d．7d．28d后进行无侧限压强度试验、结果表明：A型复合土单掺水泥的加固效果最为显著，其早期和28d强度值均随水泥掺量的增加而显著提高；c型土则单掺石灰的效果最好．最佳掺量为15％；等量复掺“水泥 石灰”时．对B型土的加固效果最好，这说明掺入一定的水泥或石灰或同时加入水泥和石灰加固由粉煤灰，炉渣、软粘土、淤泥和细砂组成的复合土在技术上是可行的．     

磁稳定床反应器中己内酰胺加氢精制过程研究

对以非晶态合金（SRNA－4）为催化剂的磁稳定床已丙酰加氢精制过程进行了研究，研究了各种操作参数对反应结果的影响，考察了催化剂的稳定性，建立了反应器模型。实验结果表明，在磁稳定床反应器中对已丙酰胺水溶液加氢精制，可使已丙酰胺水溶液的PM值为100s提高到3000s以上，催化剂寿命1350h；与工业上搅拌釜工已丙酰胺加氢精制工艺相比，催化剂耗量可降低50％以上。     

一种变种留兰香精油化学成分的研究

本文采用GC/MS法 ,研究了一变种留兰香精油的化学成分。鉴定出 39种化合物 ,主要成分为胡椒烯酮醚(30 .5 11) %、1,8-桉叶素 (2 8.791% )、烯 (9.986 % )、β -月桂烯 (8.4 81% )和 β -蒎烯 (4 .796 % ) ,而作为一般留兰香油主成分的香芹酮则未能检测到。     

A Discussion on Minimum Spout Velocity and Jet Penetration Length

The similarity and difference between the flat‐bottom and cone‐bottom cylindrical spouted beds, conical spouted beds and vertical upward jets in fluidized beds have been analyzed in this paper based on the effects of geometrical parameters on the minimum spouting velocity and operating stabilities of the spouted beds. The effect of angle on minimum spouting velocity was found to be only significant within the range of 30 to 60 degrees cone angles. Minimum spouting velocity in deep cylindrical spouted beds was proportional to the square root of the static bed height, but was proportional to the static bed height in conical spouted beds and large cylindrical spouted beds with small height‐to‐diameter ratio. The relationship between the minimum spouting velocity and the static bed height was consistent with that between jet velocity and the vertical jet penetration length in jetting fluidized beds.     

Annular wall layer thickness in circulating fluidized bed risers

The thickness of downward-flowing annular wall layers in circulating fluidized bed risers has been determined in the literature based on measured radial profiles of both local particle velocity and solids flux. The thickness of the wall layer is shown to be larger based on solids flux profiles than when based on particle velocity profiles, because fluctuations in local instantaneous particle velocity are correlated with fluctuations in local solids concentration. A new correlation is developed to predict the time-average thickness of the downflowing particle streamer layer based on solids flux measurements as a function of the cross-sectional average voidage. It successfully accounts for the variation of the wall layer thickness with axial location and solids circulation rate.     

废水处理的湿式氧化催化剂的现状与进展

本文全面、系统地介绍了20多年来,湿式氧化过程用催化剂的现状与进展。