In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^...In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^4＋ λsx3^4＋……λsx8^4 ＋η〈 ε has infinitely many solutions in positive integers x1,... ,xs.展开更多
Recently,power electronic transformers(PETs)have received widespread attention owing to their flexible networking,diverse operating modes,and abundant control objects.In this study,we established a steady-state model ...Recently,power electronic transformers(PETs)have received widespread attention owing to their flexible networking,diverse operating modes,and abundant control objects.In this study,we established a steady-state model of PETs and applied it to the power flow calculation of AC-DC hybrid systems with PETs,considering the topology,power balance,loss,and control characteristics of multi-port PETs.To address new problems caused by the introduction of the PET port and control equations to the power flow calculation,this study proposes an iterative method of AC-DC mixed power flow decoupling based on step optimization,which can achieve AC-DC decoupling and effectively improve convergence.The results show that the proposed algorithm improves the iterative method and overcomes the overcorrection and initial value sensitivity problems of conventional iterative algorithms.展开更多
Tarnavas established mixed weighted power mean inequality in 1999. A separation of weighted power mean inequslity was derived in this paper. As its applications, some separations of other inequalities were given.
A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magne...A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.展开更多
This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon...This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power curve.These properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.展开更多
It is proved that if λ1,λ2,…,λ7 are nonzero real numbers, not all of the same sign and not all in rational ratios, then for any given real numbers η and σ, 0 〈 σ 〈 1/16, the inequality ｜λ1x1^2＋λ2x2^2＋∑i...It is proved that if λ1,λ2,…,λ7 are nonzero real numbers, not all of the same sign and not all in rational ratios, then for any given real numbers η and σ, 0 〈 σ 〈 1/16, the inequality ｜λ1x1^2＋λ2x2^2＋∑i=3 7λixi^4＋η｜〈（max1≤i≤7｜xi｜-σhas infinitely many solutions in positive integers xl, x2,... , x7. Similax result is proved for ｜λ1x1^2＋λ2x2^2＋λ3x3^2＋λ4x4^4＋λ5x5^4＋λ6x6^4＋η｜〈（max1≤i≤7｜xi｜-σ.These results constitute an improvement upon those of Shi and Li.展开更多
Since the decision of the State Council in 1985 on expanding the export of electromechanical products, China’s exports of electrome-chanical products has freed itself from long fluctuation and realized fast growth. A...Since the decision of the State Council in 1985 on expanding the export of electromechanical products, China’s exports of electrome-chanical products has freed itself from long fluctuation and realized fast growth. According to statistics from the Customs Office, China’s exports of electro-mechanical products in 1995 reached US$43.86 billion, increasing 25 times in 10 years, and becoming China’s first pillar products for export. While achieving fast growth in exports, product mix has also seen sig-展开更多
Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach mod...Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach modules over a unital Banach algebra.展开更多
The mixed model of improved exponential and power function and unequal interval gray GM(1,1)model have poor accuracy in predicting the maximum pull-out load of anchor bolts.An optimal combination model was derived usi...The mixed model of improved exponential and power function and unequal interval gray GM(1,1)model have poor accuracy in predicting the maximum pull-out load of anchor bolts.An optimal combination model was derived using the optimally weighted combination theory and the minimum sum of logarithmic squared errors as the objective function.Two typical anchor bolt pull-out engineering cases were selected to compare the performance of the proposed model with those of existing ones.Results showed that the optimal combination model was suitable not only for the slow P-s curve but also for the steep P-s curve.Its accuracy and stable reliability,as well as its prediction capability classification,were better than those of the other prediction models.Therefore,the optimal combination model is an effective processing method for predicting the maximum pull-out load of anchor bolts according to measured data.展开更多
Let R b,c (n) denote the number of representations of n as the sum of one square, four cubes, one b-th power and one c-th power of natural numbers. It is shown that if b=4, 4 c 35, or b=5, 5 c 13, or b=6, 6 c 9,...Let R b,c (n) denote the number of representations of n as the sum of one square, four cubes, one b-th power and one c-th power of natural numbers. It is shown that if b=4, 4 c 35, or b=5, 5 c 13, or b=6, 6 c 9, or b=c=7, then R b,c (n)》n 5/6+1/b+1/c for all sufficiently large n.展开更多
The objective of this paper is to show that the German way towards renewable energy production could become an example for successful energy transition in other countries.Based on the Renewable Energy Act(Erneuerbare ...The objective of this paper is to show that the German way towards renewable energy production could become an example for successful energy transition in other countries.Based on the Renewable Energy Act(Erneuerbare Energien Gesetz(EEG))in the year 2000 the most important steps for this transition seemed to be start-ups with relevant and reliable feed-in tariffs,the involvement of“many single”intelligently and digitally connected producers to form a kind of“swarm-energy.”In addition regional smart grids,a national grid structure with sufficient capacity,and,last but not least,implementation of energy efficiency tools in the building,construction and transport sector,are necessary driving sources.展开更多
基金the National Natural Science Foundation of China(10671056)
文摘In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^4＋ λsx3^4＋……λsx8^4 ＋η〈 ε has infinitely many solutions in positive integers x1,... ,xs.
基金supported by the National Key Research and Development Program of China(2017YFB0903300).
文摘Recently,power electronic transformers(PETs)have received widespread attention owing to their flexible networking,diverse operating modes,and abundant control objects.In this study,we established a steady-state model of PETs and applied it to the power flow calculation of AC-DC hybrid systems with PETs,considering the topology,power balance,loss,and control characteristics of multi-port PETs.To address new problems caused by the introduction of the PET port and control equations to the power flow calculation,this study proposes an iterative method of AC-DC mixed power flow decoupling based on step optimization,which can achieve AC-DC decoupling and effectively improve convergence.The results show that the proposed algorithm improves the iterative method and overcomes the overcorrection and initial value sensitivity problems of conventional iterative algorithms.
基金Project supported by National Natural Science Foundation of China （Grant No. 10271071）
文摘Tarnavas established mixed weighted power mean inequality in 1999. A separation of weighted power mean inequslity was derived in this paper. As its applications, some separations of other inequalities were given.
基金supported by ITER Program of China(973 Program)(No.2011GB109002)National Natural Science Foundation of China(No.11275056)Hefei University of Technology Doctor Research Foundation of China(No.2011HGBZ1292)
文摘A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.
基金Supported by the Shanghai Institute of Technology(10120K146098)Shanghai Municipal Education Commission(1021ZK151009017)
文摘This paper is concerned with the design and application of coaxial mixers with the aid of analysis of interaction between each individual impeller. Two types of coaxial mixers pitched blade turbine(PBT)-helical ribbon(HR)and inner-outer HR operated in laminar regime were studied experimentally and numerically. The interaction implies synergistic and interference effects, which was revealed through the investigation of axial circulation rate, energy dissipation rate and power consumption. The influence factors including rotational speed ratio,rotating mode and impeller configuration were explored systematically. Quantitative analysis of power consumption involves three parameters: rate of variation in power consumption, interactive mode and ratio of power consumption. Analysis indicated that some important properties were embodied in the power curve.These properties are one-way and two-way interactions, critical speed ratio and dominant impeller. Finally, a new suggestion for power estimation was given.
基金Supported by the National Natural Science Foundation of China(11201107,11271283,11501435)Supported by the Natural Science Foundation of Anhui Province(1208085QA01)
文摘It is proved that if λ1,λ2,…,λ7 are nonzero real numbers, not all of the same sign and not all in rational ratios, then for any given real numbers η and σ, 0 〈 σ 〈 1/16, the inequality ｜λ1x1^2＋λ2x2^2＋∑i=3 7λixi^4＋η｜〈（max1≤i≤7｜xi｜-σhas infinitely many solutions in positive integers xl, x2,... , x7. Similax result is proved for ｜λ1x1^2＋λ2x2^2＋λ3x3^2＋λ4x4^4＋λ5x5^4＋λ6x6^4＋η｜〈（max1≤i≤7｜xi｜-σ.These results constitute an improvement upon those of Shi and Li.
文摘Since the decision of the State Council in 1985 on expanding the export of electromechanical products, China’s exports of electrome-chanical products has freed itself from long fluctuation and realized fast growth. According to statistics from the Customs Office, China’s exports of electro-mechanical products in 1995 reached US$43.86 billion, increasing 25 times in 10 years, and becoming China’s first pillar products for export. While achieving fast growth in exports, product mix has also seen sig-
基金supported by the National Natural Science Foundation of China (10671013,60972089,11171022)
文摘Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach modules over a unital Banach algebra.
基金The National Natural Science Foundation of China(No.51778485).
文摘The mixed model of improved exponential and power function and unequal interval gray GM(1,1)model have poor accuracy in predicting the maximum pull-out load of anchor bolts.An optimal combination model was derived using the optimally weighted combination theory and the minimum sum of logarithmic squared errors as the objective function.Two typical anchor bolt pull-out engineering cases were selected to compare the performance of the proposed model with those of existing ones.Results showed that the optimal combination model was suitable not only for the slow P-s curve but also for the steep P-s curve.Its accuracy and stable reliability,as well as its prediction capability classification,were better than those of the other prediction models.Therefore,the optimal combination model is an effective processing method for predicting the maximum pull-out load of anchor bolts according to measured data.
文摘Let R b,c (n) denote the number of representations of n as the sum of one square, four cubes, one b-th power and one c-th power of natural numbers. It is shown that if b=4, 4 c 35, or b=5, 5 c 13, or b=6, 6 c 9, or b=c=7, then R b,c (n)》n 5/6+1/b+1/c for all sufficiently large n.
文摘The objective of this paper is to show that the German way towards renewable energy production could become an example for successful energy transition in other countries.Based on the Renewable Energy Act(Erneuerbare Energien Gesetz(EEG))in the year 2000 the most important steps for this transition seemed to be start-ups with relevant and reliable feed-in tariffs,the involvement of“many single”intelligently and digitally connected producers to form a kind of“swarm-energy.”In addition regional smart grids,a national grid structure with sufficient capacity,and,last but not least,implementation of energy efficiency tools in the building,construction and transport sector,are necessary driving sources.
