To study the congestion of interrupted flow on urban roads, a comprehensive evaluation method is proposed. First, based on the results of correlation analysis between different parameters of interrupted flow, the traf...To study the congestion of interrupted flow on urban roads, a comprehensive evaluation method is proposed. First, based on the results of correlation analysis between different parameters of interrupted flow, the traffic parameters of interrupted traffic flow are divided into two categories： the basic parameters and the operation parameters. Polynomial regression is used to formulize the nonlinear relationships between the basic parameters and the operation parameters. Then, the congestion model incorporating both operational and volume characteristics of traffic flow is proposed. The inputs of the model are the basic parameters, while the output is a dimensionless index value between 0 and 1. Finally, the proposed methods are compared with existing evaluation measures of congestion. Results show that the proposed indices can capture the variation of both the basic parameters and the operation parameters, which is more balanced compared with the existing evaluation measures.展开更多
结合前期水模拟结果,利用FLUENT软件对河北钢铁集团承德钢铁集团有限公司炼钢二厂120 t LF进行了底吹氩气的三相流数值模拟,模拟结果表明:优化后钢包熔池速度与湍动能分别增大了11.8%和18.3%,死区体积减小了33.7%,有利于钢包内熔池的传...结合前期水模拟结果,利用FLUENT软件对河北钢铁集团承德钢铁集团有限公司炼钢二厂120 t LF进行了底吹氩气的三相流数值模拟,模拟结果表明:优化后钢包熔池速度与湍动能分别增大了11.8%和18.3%,死区体积减小了33.7%,有利于钢包内熔池的传热、传质以及夹杂物去除等过程。将优化后钢包底吹位置应用于该厂120 t LF,结果表明:T.O去除率提高了5.9%,w(N)降低了6.4%;总夹杂物去除率提高了5.5%;大型夹杂物去除率提高4.9%。达到改善钢包结构,优化钢液流动状态,提高LF精炼的目的。展开更多
Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numeri...Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numerical solutions of the governing equations of unsteady two-dimensional flow of a polytropic gas are investigated. The numerical results reveal that the new technique is very effective and gives high accuracy, good convergence and reasonable stability.展开更多
In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation...In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation loading, especially at the stage of its design, is an extremely important issue because of the choice of the processing equipment of the main circuit or protection devices. In the range of investigations of railway traction substation B in vicinity of Cracow （Poland）, the measurements of current load in hours 4：00 a.m.-8：00 p.m. were realized. The measurements for the analysis were chosen from those realized between 6：00 a.m.-8：00 a.m. （the morning rush time）. Due to the sampling of 2 h summit with a frequency of 2 kHz, the recorded data set contains 1.44 ~ 107 elements. Therefore, the necessary transformation of data was to lower frequency 1 Hz, 10 Hz and 50 Hz. The results of the analysis presented below indicate the effect of such conduct on the obtained results for the parameters of time series models. In view of the unsatisfactory effects of the polynomial approximation, there is a need to seek a more efficient approximation method for achieving the optimum compatibility with the measured process. Continued research should lead to the formulation of procedures, which will determine an acceptable accuracy of the expected variability of traction substation loads.展开更多
The authors prove the space of harmonic functions with polynomial growth of a fixed rate on a complete noncompact Riemannian manifold with asymptotically nonnegative curvature is finite dimensional.
Very recently, it was observed that the temperature of nanofluids is finally governed by second-order ordinary differential equations with variable coefficients of exponential orders. Such coefficients were then trans...Very recently, it was observed that the temperature of nanofluids is finally governed by second-order ordinary differential equations with variable coefficients of exponential orders. Such coefficients were then transformed to polynomials type by using new independent variables. In this paper, a class of second-order ordinary differential equations with variable coefficients of polynomials type has been solved analytically. The analytical solution is expressed in terms of a hypergeometric function with generalized parameters. Moreover, applications of the present results have been applied on some selected nanofluids problems in the literature. The exact solutions in the literature were derived as special cases of our generalized analytical solution.展开更多
Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of el...Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of electromagnetic losses,flux leakage or saturation of iron.In this paper,based on results from an experimental set-up designed to study magnetic force,a novel parametric model is presented in the form of a nonlinear polynomial with unknown coefficients.The parameters of the proposed model are identified using the weighted residual method.Validations of the model identified were performed by comparing the results in time and frequency domains.The results show a good correlation between experiments and numerical simulations.展开更多
The authors introduce a kind of slowly increasing cohomology HS＊（X） for a discrete metric space X with polynomial growth, and construct a character map from the slowly increasing cohomology HS＊ （X） into HC＊ont ...The authors introduce a kind of slowly increasing cohomology HS＊（X） for a discrete metric space X with polynomial growth, and construct a character map from the slowly increasing cohomology HS＊ （X） into HC＊ont （S（X））, the continuous cyclic cohomol- ogy of the smooth subalgebra S（X） of the uniform Roe algebra B＊ （X）. As an application, it is shown that the fundamental cocycle, associated with a uniformly contractible complete Riemannian manifold M with polynomial volume growth and polynomial contractibility radius growth, is slowly increasing.展开更多
The semisimple structure, which generalizes the complex and the paracomplex structures, is considered. The authors classify all the homogeneous semisimple spaces whose underlying spaces are G/C(W) 0 , where ...The semisimple structure, which generalizes the complex and the paracomplex structures, is considered. The authors classify all the homogeneous semisimple spaces whose underlying spaces are G/C(W) 0 , where G is a real simple Lie Group, W∈ g, C(W) 0 is the identity component of the centralizer C(W) of W in G .展开更多
基金The National High Technology Research and Development Program of China(863 Program)(No.2011AA110302-01)
文摘To study the congestion of interrupted flow on urban roads, a comprehensive evaluation method is proposed. First, based on the results of correlation analysis between different parameters of interrupted flow, the traffic parameters of interrupted traffic flow are divided into two categories： the basic parameters and the operation parameters. Polynomial regression is used to formulize the nonlinear relationships between the basic parameters and the operation parameters. Then, the congestion model incorporating both operational and volume characteristics of traffic flow is proposed. The inputs of the model are the basic parameters, while the output is a dimensionless index value between 0 and 1. Finally, the proposed methods are compared with existing evaluation measures of congestion. Results show that the proposed indices can capture the variation of both the basic parameters and the operation parameters, which is more balanced compared with the existing evaluation measures.
文摘结合前期水模拟结果,利用FLUENT软件对河北钢铁集团承德钢铁集团有限公司炼钢二厂120 t LF进行了底吹氩气的三相流数值模拟,模拟结果表明:优化后钢包熔池速度与湍动能分别增大了11.8%和18.3%,死区体积减小了33.7%,有利于钢包内熔池的传热、传质以及夹杂物去除等过程。将优化后钢包底吹位置应用于该厂120 t LF,结果表明:T.O去除率提高了5.9%,w(N)降低了6.4%;总夹杂物去除率提高了5.5%;大型夹杂物去除率提高4.9%。达到改善钢包结构,优化钢液流动状态,提高LF精炼的目的。
文摘Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numerical solutions of the governing equations of unsteady two-dimensional flow of a polytropic gas are investigated. The numerical results reveal that the new technique is very effective and gives high accuracy, good convergence and reasonable stability.
文摘In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation loading, especially at the stage of its design, is an extremely important issue because of the choice of the processing equipment of the main circuit or protection devices. In the range of investigations of railway traction substation B in vicinity of Cracow （Poland）, the measurements of current load in hours 4：00 a.m.-8：00 p.m. were realized. The measurements for the analysis were chosen from those realized between 6：00 a.m.-8：00 a.m. （the morning rush time）. Due to the sampling of 2 h summit with a frequency of 2 kHz, the recorded data set contains 1.44 ~ 107 elements. Therefore, the necessary transformation of data was to lower frequency 1 Hz, 10 Hz and 50 Hz. The results of the analysis presented below indicate the effect of such conduct on the obtained results for the parameters of time series models. In view of the unsatisfactory effects of the polynomial approximation, there is a need to seek a more efficient approximation method for achieving the optimum compatibility with the measured process. Continued research should lead to the formulation of procedures, which will determine an acceptable accuracy of the expected variability of traction substation loads.
基金Project supported by the National Natural Science Foundation of China (No.10271089).
文摘The authors prove the space of harmonic functions with polynomial growth of a fixed rate on a complete noncompact Riemannian manifold with asymptotically nonnegative curvature is finite dimensional.
文摘Very recently, it was observed that the temperature of nanofluids is finally governed by second-order ordinary differential equations with variable coefficients of exponential orders. Such coefficients were then transformed to polynomials type by using new independent variables. In this paper, a class of second-order ordinary differential equations with variable coefficients of polynomials type has been solved analytically. The analytical solution is expressed in terms of a hypergeometric function with generalized parameters. Moreover, applications of the present results have been applied on some selected nanofluids problems in the literature. The exact solutions in the literature were derived as special cases of our generalized analytical solution.
文摘Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of electromagnetic losses,flux leakage or saturation of iron.In this paper,based on results from an experimental set-up designed to study magnetic force,a novel parametric model is presented in the form of a nonlinear polynomial with unknown coefficients.The parameters of the proposed model are identified using the weighted residual method.Validations of the model identified were performed by comparing the results in time and frequency domains.The results show a good correlation between experiments and numerical simulations.
基金Project supported by the National Natural Science Foundation of China(No.11171245)the Major Program of National Natural Science Foundation of China(No.10731020)the Shanghai Municipal Natural Science Foundation(No.09ZR1402000)
文摘The authors introduce a kind of slowly increasing cohomology HS＊（X） for a discrete metric space X with polynomial growth, and construct a character map from the slowly increasing cohomology HS＊ （X） into HC＊ont （S（X））, the continuous cyclic cohomol- ogy of the smooth subalgebra S（X） of the uniform Roe algebra B＊ （X）. As an application, it is shown that the fundamental cocycle, associated with a uniformly contractible complete Riemannian manifold M with polynomial volume growth and polynomial contractibility radius growth, is slowly increasing.
文摘The semisimple structure, which generalizes the complex and the paracomplex structures, is considered. The authors classify all the homogeneous semisimple spaces whose underlying spaces are G/C(W) 0 , where G is a real simple Lie Group, W∈ g, C(W) 0 is the identity component of the centralizer C(W) of W in G .
