Empirical data show that most of the degree distribution of airline networks assume a double power law. In this work, firstly, we assume cities as sites, flight between two cities as an edge between two sites, and bui...Empirical data show that most of the degree distribution of airline networks assume a double power law. In this work, firstly, we assume cities as sites, flight between two cities as an edge between two sites, and build a dynamic evolution model for airline networks by improving the BA model, in which the conception of attractiveness plays a decisive role in the course of evolution of the networks. To this end, we discuss whether the attractiveness depends on the site label s or not separately, finally we obtain analytic degree distribution. As a result, if the attractiveness of a site is independent of the degree distribution of sites, which will follow the double power law, otherwise, it will be scale-free. Moreover, degree distribution depends on the parameters of the models, and some parameters aye more sensitive than others.展开更多
Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of...Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of ECTr for production of inner blisks(bladed disks)with a special chamfer structure at blade tip.Due to the existence of chamfer,the ECTr process of inner blades is in a non-equilibrium state during the early stages,and the physical field changes in the machining gap are complex,making it difficult to predict the forming process.In this paper,a dynamic evolution model(DEM)of inner blade ECTr with a special chamfer at blade tip structure is proposed,and an ECTr multi-physical fields simulation study was carried out.The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate.In addition,the dis-tributions of current density,electrolyte flow rate,bubble volume fraction,temperature rise,and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results.Subsequently,a series of ECTr experiments were conducted,in which,as the feed rate increased,the surface quality and machining accuracy of the inner blades were improved.Compared with the simulation results,the error in machining accu-racy of the chamfer profile is controlled within±2%,and the machining accuracy of the blade full profile was controlled within±0.2 mm,indicating that the model proposed in this study was effec-tive in predicting the evolution of inner blades ECTr with chamfer structures at blade tip.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 10975057the Programme of Introducing Talents of Discipline to Universities under Grant No B08033
文摘Empirical data show that most of the degree distribution of airline networks assume a double power law. In this work, firstly, we assume cities as sites, flight between two cities as an edge between two sites, and build a dynamic evolution model for airline networks by improving the BA model, in which the conception of attractiveness plays a decisive role in the course of evolution of the networks. To this end, we discuss whether the attractiveness depends on the site label s or not separately, finally we obtain analytic degree distribution. As a result, if the attractiveness of a site is independent of the degree distribution of sites, which will follow the double power law, otherwise, it will be scale-free. Moreover, degree distribution depends on the parameters of the models, and some parameters aye more sensitive than others.
基金the National Nature Science Foundation of China (52275435)the National Natural Science Foundation of China for Creative Research Groups (51921003)the National Science and Technology Major Project (2017-VII-0004-0097).
文摘Electrochemical trepanning(ECTr)is an effective electrochemical machining(ECM)technique that can be used to manufacture the integral components of aero-engine compressors.This study focused on the dynamic evolution of ECTr for production of inner blisks(bladed disks)with a special chamfer structure at blade tip.Due to the existence of chamfer,the ECTr process of inner blades is in a non-equilibrium state during the early stages,and the physical field changes in the machining gap are complex,making it difficult to predict the forming process.In this paper,a dynamic evolution model(DEM)of inner blade ECTr with a special chamfer at blade tip structure is proposed,and an ECTr multi-physical fields simulation study was carried out.The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate.In addition,the dis-tributions of current density,electrolyte flow rate,bubble volume fraction,temperature rise,and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results.Subsequently,a series of ECTr experiments were conducted,in which,as the feed rate increased,the surface quality and machining accuracy of the inner blades were improved.Compared with the simulation results,the error in machining accu-racy of the chamfer profile is controlled within±2%,and the machining accuracy of the blade full profile was controlled within±0.2 mm,indicating that the model proposed in this study was effec-tive in predicting the evolution of inner blades ECTr with chamfer structures at blade tip.
