Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varietie...Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.展开更多
Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important rol...Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important role in the social and economic development. In China, there are many accounting supervision problems in accounting practice at present, and a lot of the problems have exerted a negative impact on the social and economic life. Therefore, the causes for these problems are discussed and analyzed, so that the corresponding methods and measures are proposed for solving the existing problems and promoting the accounting supervision to play a better and greater role in the financial management of enterprises.展开更多
Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important rol...Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important role in the social and economic development. In China, there are many accounting supervision problems in accounting practice at present, and a lot of the problems have exerted a negative impact on the social and economic life. Therefore, the causes for these problems are discussed and analyzed, so that the corresponding methods and measures are proposed for solving the existing problems and promoting the accounting supervision to play a better and greater role in the financial management of enterprises.展开更多
Experimental investigation was conducted to investigate the impingement heat transfer performance of a synthetic jet driven by piston actuator on a constant heat flux surface. Effects of jet formation frequency, nozzl...Experimental investigation was conducted to investigate the impingement heat transfer performance of a synthetic jet driven by piston actuator on a constant heat flux surface. Effects of jet formation frequency, nozzle-to-surface spacing ratio and con- jugation of cross flow were considered. The synthetic jet is of stronger penetration and heat transfer capacity when the piston reciprocates at relatively high frequency. Similar to the continuous jet impingement, nozzle-to-surface spacing ratio plays an important role in the heat transfer enhancement of synthetic jet. The optimum nozzle-to-surface spacing ratio corresponding to maximum heat transfer enhancement is considerably high in the synthetic jet, as compared to that in a continuous jet, which indicates that the synthetic jet introduces a stronger entrainment and more vigorous penetration in the surrounding fluid. The convective heat transfer capacity is enhanced significantly under the conjugate action of a synthetic jet and cross flow in com- narison with their individual action.展开更多
文摘Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.
文摘Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important role in the social and economic development. In China, there are many accounting supervision problems in accounting practice at present, and a lot of the problems have exerted a negative impact on the social and economic life. Therefore, the causes for these problems are discussed and analyzed, so that the corresponding methods and measures are proposed for solving the existing problems and promoting the accounting supervision to play a better and greater role in the financial management of enterprises.
文摘Accounting supervision is a management activity to monitor and supervise the production, business operation, and budget implementation in enterprises, and a good accounting supervision plays an extremely important role in the social and economic development. In China, there are many accounting supervision problems in accounting practice at present, and a lot of the problems have exerted a negative impact on the social and economic life. Therefore, the causes for these problems are discussed and analyzed, so that the corresponding methods and measures are proposed for solving the existing problems and promoting the accounting supervision to play a better and greater role in the financial management of enterprises.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50276028,51106073)
文摘Experimental investigation was conducted to investigate the impingement heat transfer performance of a synthetic jet driven by piston actuator on a constant heat flux surface. Effects of jet formation frequency, nozzle-to-surface spacing ratio and con- jugation of cross flow were considered. The synthetic jet is of stronger penetration and heat transfer capacity when the piston reciprocates at relatively high frequency. Similar to the continuous jet impingement, nozzle-to-surface spacing ratio plays an important role in the heat transfer enhancement of synthetic jet. The optimum nozzle-to-surface spacing ratio corresponding to maximum heat transfer enhancement is considerably high in the synthetic jet, as compared to that in a continuous jet, which indicates that the synthetic jet introduces a stronger entrainment and more vigorous penetration in the surrounding fluid. The convective heat transfer capacity is enhanced significantly under the conjugate action of a synthetic jet and cross flow in com- narison with their individual action.
