A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve...A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works展开更多
The computational flow rate feedback and control method, which can be used in proportional valve controlled hydraulic elevators, is discussed and analyzed. In a hydraulic elevator with this method, microprocessor rece...The computational flow rate feedback and control method, which can be used in proportional valve controlled hydraulic elevators, is discussed and analyzed. In a hydraulic elevator with this method, microprocessor receives pressure information from the pressure transducers and computes the flow rate through the proportional valve based on pressure-flow conversion real time algorithm. This hydraulic elevator is of lower cost and energy consumption than the conventional closed loop control hydraulic elevator whose flow rate is measured by a flow meter. Experiments arc carried out on a test rig which could simulate the load of hydraulic elevator. According to the experiment results, the means to modify the pressure-flow conversion algorithm are pointed out.展开更多
The wear rate between the rotors of a hypotrochoidal gear pump is characterized.Using the knowledge of shape design on the rotors,the contact stresses without hydrodynamic effect between the rotor teeth were evaluated...The wear rate between the rotors of a hypotrochoidal gear pump is characterized.Using the knowledge of shape design on the rotors,the contact stresses without hydrodynamic effect between the rotor teeth were evaluated through the calculation of the Hertzian contact stress.Based on the above results and the sliding velocity between the rotors,a genetic algorithm (GA) was used as an optimization technique forminimizing the wear rate proportional factor (WRPF).The result shows that the wear rate or the WRPF can be reduced considerably,e.g.approximately 12.8%,throughout the optimization using GA.展开更多
Next year marks 100 years since the introduction of the first law on income tax in Russia.Over this period a number of reforms on income tax has been conducted,and various results have been achieved.It has become of i...Next year marks 100 years since the introduction of the first law on income tax in Russia.Over this period a number of reforms on income tax has been conducted,and various results have been achieved.It has become of importance to analyze the experience of income tax reforms.This paper aims to study the formation and reformation of income tax in Russia.This work singles out and analyzes five stages of formation of income tax in Russia-the main focus being on the analysis of the two last stages of income tax functioning:during the transition to a market economy and in a market economy.The paper identifies the main prerequisites of the personal income tax reform in 2001 and analyzes the results of the reform.The paper validates the conclusion that the reform had mixed results.The transition to the proportional model of personal income tax failed to significantly affect the fiscal significance of this tax,and did not lead to the desired legalization of salaries or a drastic decrease in the share of wages paid off the books.Moreover,the income tax reform did not result in a significant decrease in the number of tax concessions that reduce the neutrality and fiscal significance of the tax.At the same time,the income tax reform made it possible to drastically increase the neutrality and economic effectiveness of this tax,reduced the cost of administration for taxpayers,withholding agents,and tax services.In light of a possible new reform of the tax system,this article makes the assumption that the return to progressive tax rates will fall short of expectations of the poor,as the wealth gap in Russian society will not be reduced.This paper draws the conclusion that as the achievement of the expected results is not guaranteed,preserving the existing model of personal income tax may be the most pragmatic option.At the same time,it might be advisable to take an inventory of tax deductions,and possibly cancel some of them that are exclusively enjoyed by the rich in the first place.展开更多
基金supported by Program for New Century Excellent Talents in University of China (No.NCET-05-0528).
文摘A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works
基金This project is supported by State Scientific Project of the Tenth Five-year Plan of China(No.2002BA208B02)National Natural Science Foundation of China(No.50305032).
文摘The computational flow rate feedback and control method, which can be used in proportional valve controlled hydraulic elevators, is discussed and analyzed. In a hydraulic elevator with this method, microprocessor receives pressure information from the pressure transducers and computes the flow rate through the proportional valve based on pressure-flow conversion real time algorithm. This hydraulic elevator is of lower cost and energy consumption than the conventional closed loop control hydraulic elevator whose flow rate is measured by a flow meter. Experiments arc carried out on a test rig which could simulate the load of hydraulic elevator. According to the experiment results, the means to modify the pressure-flow conversion algorithm are pointed out.
基金supported by Changwon National University in 2010,Korea
文摘The wear rate between the rotors of a hypotrochoidal gear pump is characterized.Using the knowledge of shape design on the rotors,the contact stresses without hydrodynamic effect between the rotor teeth were evaluated through the calculation of the Hertzian contact stress.Based on the above results and the sliding velocity between the rotors,a genetic algorithm (GA) was used as an optimization technique forminimizing the wear rate proportional factor (WRPF).The result shows that the wear rate or the WRPF can be reduced considerably,e.g.approximately 12.8%,throughout the optimization using GA.
文摘Next year marks 100 years since the introduction of the first law on income tax in Russia.Over this period a number of reforms on income tax has been conducted,and various results have been achieved.It has become of importance to analyze the experience of income tax reforms.This paper aims to study the formation and reformation of income tax in Russia.This work singles out and analyzes five stages of formation of income tax in Russia-the main focus being on the analysis of the two last stages of income tax functioning:during the transition to a market economy and in a market economy.The paper identifies the main prerequisites of the personal income tax reform in 2001 and analyzes the results of the reform.The paper validates the conclusion that the reform had mixed results.The transition to the proportional model of personal income tax failed to significantly affect the fiscal significance of this tax,and did not lead to the desired legalization of salaries or a drastic decrease in the share of wages paid off the books.Moreover,the income tax reform did not result in a significant decrease in the number of tax concessions that reduce the neutrality and fiscal significance of the tax.At the same time,the income tax reform made it possible to drastically increase the neutrality and economic effectiveness of this tax,reduced the cost of administration for taxpayers,withholding agents,and tax services.In light of a possible new reform of the tax system,this article makes the assumption that the return to progressive tax rates will fall short of expectations of the poor,as the wealth gap in Russian society will not be reduced.This paper draws the conclusion that as the achievement of the expected results is not guaranteed,preserving the existing model of personal income tax may be the most pragmatic option.At the same time,it might be advisable to take an inventory of tax deductions,and possibly cancel some of them that are exclusively enjoyed by the rich in the first place.
