In this paper, we derive the Baskakov-Kantorovich operators Vn（f; x） the complete asymptotic expansion in the form of all coefficients of n^-k, k =0, 1 … being calculated explicitly. As a corollary, we also get the...In this paper, we derive the Baskakov-Kantorovich operators Vn（f; x） the complete asymptotic expansion in the form of all coefficients of n^-k, k =0, 1 … being calculated explicitly. As a corollary, we also get the Voronovskaja-type result for the operators.展开更多
A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was es...A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.展开更多
In this paper, using exponential Riordan arrays, we investigate the Bessel numbers and Bessel matrices. By exploring links between the Bessel matrices, the Stirling matrices and the degenerate Stirling matrices, we sh...In this paper, using exponential Riordan arrays, we investigate the Bessel numbers and Bessel matrices. By exploring links between the Bessel matrices, the Stirling matrices and the degenerate Stirling matrices, we show that the Bessel numbers are special case of the degenerate Stirling numbers, and derive explicit formulas for the Bessel numbers in terms of the Stirling numbers and binomial coefficients.展开更多
Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its ...Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its absence of moving mechanical part. In this paper, the influence of the dimensions of the main parts of the small- scale Stifling thermo-acoustic engine was numerically simulated using a computer code called DeltaEC. The resonator and the resonator cavity were found to be the most convenient and effective in improving the perfor- mance of the engine. Based on the numerical simulation, a small-scale Stifling thermo-acoustic engine were constructed and experimentally investigated. Currently, with a resonator length of only 1 m, the working frequency of the engine was decreased to 90 Hz and the onset temperature difference was decreased to 198.2 K.展开更多
基金Supported by the Natural Science Foundation of Beijing(1072006)Supported by NSFC(10871017)
文摘In this paper, we derive the Baskakov-Kantorovich operators Vn（f; x） the complete asymptotic expansion in the form of all coefficients of n^-k, k =0, 1 … being calculated explicitly. As a corollary, we also get the Voronovskaja-type result for the operators.
文摘A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.
基金Supported by the Natural Science Foundation of Gansu Province (Grant No.1010RJZA049)
文摘In this paper, using exponential Riordan arrays, we investigate the Bessel numbers and Bessel matrices. By exploring links between the Bessel matrices, the Stirling matrices and the degenerate Stirling matrices, we show that the Bessel numbers are special case of the degenerate Stirling numbers, and derive explicit formulas for the Bessel numbers in terms of the Stirling numbers and binomial coefficients.
文摘Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its absence of moving mechanical part. In this paper, the influence of the dimensions of the main parts of the small- scale Stifling thermo-acoustic engine was numerically simulated using a computer code called DeltaEC. The resonator and the resonator cavity were found to be the most convenient and effective in improving the perfor- mance of the engine. Based on the numerical simulation, a small-scale Stifling thermo-acoustic engine were constructed and experimentally investigated. Currently, with a resonator length of only 1 m, the working frequency of the engine was decreased to 90 Hz and the onset temperature difference was decreased to 198.2 K.
