This paper deals with Hilbert's 16th problem and its generalizations. The configurations of all closed branches of an algebraic curve of degree n are discussed. The maximum number of sheets for an algebraic eq...This paper deals with Hilbert's 16th problem and its generalizations. The configurations of all closed branches of an algebraic curve of degree n are discussed. The maximum number of sheets for an algebraic equation of degree n and the maximum number of limit cycles for a planar algebraic autonomous system are achieved. The author also considers different generalizations and some related problems.展开更多
Supercritical CO_(2)Brayton cycle has high efficiency,compactness,and excellent power generation potential.In the design of the cycle,some parameters,such as recuperator pinch point temperature difference(ΔTrec,pp),t...Supercritical CO_(2)Brayton cycle has high efficiency,compactness,and excellent power generation potential.In the design of the cycle,some parameters,such as recuperator pinch point temperature difference(ΔTrec,pp),turbine inlet temperature(Ttur,in),and maximum cycle pressure(pmax),are often preset without optimization.Furthermore,different preferences on efficiency and cost tradeoff can significantly affect the optimal design of the cycle,and the influence of different parameters on the design condition and the optimum cycle configuration becomes unclear as the preference changes.In this study,different preferences on efficiency and cost tradeoff are considered,and the effects of cycle configuration and optimization parameter addition on the tradeoff are investigated.In addition,four configurations under different preferences on tradeoff are recommended.Results show that the design condition parametersΔT_(rec,pp) decrease and T_(tur,in) and pmax increase as the preference of thermal efficiency(W_(th))increases.Different optimized parameters affect the results of the design point and cycle performance.In addition,the simple recuperative cycle and reheating cycle are recommended when low cycle initial cost dominates(W_(th)<0.598),and the recompression cycle and intercooling cycle are recommended when high cycle thermal efficiency dominates(W_(th)>0.701).The decision maker can select appropriate configuration according to specific preferences.展开更多
Theoretical foundations of programming systems from modules, objects, components, services are given. Identified relevant theory of programming proposed by the author with the participation of students and postgraduat...Theoretical foundations of programming systems from modules, objects, components, services are given. Identified relevant theory of programming proposed by the author with the participation of students and postgraduates: graph modular programming theory with graph representation as an adjacency matrix for mathematical achievability of graph vertices;theory of generating programming and theory of software factories;theory of graph object and component modeling (OCM) by means of logic and algebra-mathematical theory of determining individual elements of complex systems;theory of system programming based on ontological and service-component models (SOA, SCA) with security and quality systems. The Internet Smart and Nanotechnology are given for perspective transition of computer technology to nanotechnology.展开更多
文摘This paper deals with Hilbert's 16th problem and its generalizations. The configurations of all closed branches of an algebraic curve of degree n are discussed. The maximum number of sheets for an algebraic equation of degree n and the maximum number of limit cycles for a planar algebraic autonomous system are achieved. The author also considers different generalizations and some related problems.
基金supported by the Beijing Natural Science Foundation(Grant No.3202014).
文摘Supercritical CO_(2)Brayton cycle has high efficiency,compactness,and excellent power generation potential.In the design of the cycle,some parameters,such as recuperator pinch point temperature difference(ΔTrec,pp),turbine inlet temperature(Ttur,in),and maximum cycle pressure(pmax),are often preset without optimization.Furthermore,different preferences on efficiency and cost tradeoff can significantly affect the optimal design of the cycle,and the influence of different parameters on the design condition and the optimum cycle configuration becomes unclear as the preference changes.In this study,different preferences on efficiency and cost tradeoff are considered,and the effects of cycle configuration and optimization parameter addition on the tradeoff are investigated.In addition,four configurations under different preferences on tradeoff are recommended.Results show that the design condition parametersΔT_(rec,pp) decrease and T_(tur,in) and pmax increase as the preference of thermal efficiency(W_(th))increases.Different optimized parameters affect the results of the design point and cycle performance.In addition,the simple recuperative cycle and reheating cycle are recommended when low cycle initial cost dominates(W_(th)<0.598),and the recompression cycle and intercooling cycle are recommended when high cycle thermal efficiency dominates(W_(th)>0.701).The decision maker can select appropriate configuration according to specific preferences.
文摘Theoretical foundations of programming systems from modules, objects, components, services are given. Identified relevant theory of programming proposed by the author with the participation of students and postgraduates: graph modular programming theory with graph representation as an adjacency matrix for mathematical achievability of graph vertices;theory of generating programming and theory of software factories;theory of graph object and component modeling (OCM) by means of logic and algebra-mathematical theory of determining individual elements of complex systems;theory of system programming based on ontological and service-component models (SOA, SCA) with security and quality systems. The Internet Smart and Nanotechnology are given for perspective transition of computer technology to nanotechnology.
