Non-linear programming analysis suggests that employment effects of minimum wage regulation are the result not only of the regulation itself but also of the external regulatory environment. At a certain level, the reg...Non-linear programming analysis suggests that employment effects of minimum wage regulation are the result not only of the regulation itself but also of the external regulatory environment. At a certain level, the regulatory environment intensifies the effect on employment of minimum wage regulation. Empirical studies based on survey data from 439 enterprises in Guangdong and Fujian show that minimum wage rises had a greater impact on the employment of rural migrant workers in 2008 than in 2007, although no significant change was observed among workers who were permanent urban residents. Further analysis shows that the greater impact on migrant workers derives mainly from the strengthened regulatory environment brought about by the Employment Contracts Law. The permanent urban workforce has not been similarly affected because their interests have been given priority under the dual employment system. This reminds us that the employment effects of the Employment Contracts Law may be realized indirectly through other regulatory measures, including strengthened minimum wage regulation.展开更多
We propose a novel kind of compound permanent magnet synchronous machine (CPMSM), which is applicable in low-speed and high-torque situations. We first explain the structure of the CPMSM. Based on theoretically deduci...We propose a novel kind of compound permanent magnet synchronous machine (CPMSM), which is applicable in low-speed and high-torque situations. We first explain the structure of the CPMSM. Based on theoretically deducing the calculation formulae of the CPMSM electromagnetic parameters, we analyze the operating characteristics of the CPMSM, and obtain the power-angle curves and working curves. The no-load magnetic field distribution and the cogging torque are analyzed by applying the finite element method of three-dimensional (3D) magnetic fields, to determine the no-load leakage coefficient and the waveform of the cogging torque. Furthermore, the optimal parameters of the permanent magnet for reducing the cogging torque are determined. An important application target of the CPMSM is in directdrive pumping units. We have installed and tested a direct- drive pumping unit in an existing oil well. Test results show that the power consumption of the direct-drive pumping unit driven by CPMSM is 61.1% of that of the beam-pumping unit, and that the floor space and weight are only 50% of those of a beam-pumping unit. The noise output does not exceed 58 dB in a range of 1 m around the machine when the machine is 1.5 m from the ground.展开更多
基金the National Natural Science Foundation sponsored project, "The Employment Effects of Labor Regulation on Rural Migrant Workers and Administrative Policies: With a Focus on Minimum Wage Rises" (劳动规制对农民工的就业影响及管理政策研究:以提高最低工资标准为例)sponsored by the General Administration of Quality Supervision, Inspection and Quarantine and the Renmin University of China, "The Impact of Foreign Technical Measures on China’s Export" (国外基础性贸易措施对我 们出口的影响)
文摘Non-linear programming analysis suggests that employment effects of minimum wage regulation are the result not only of the regulation itself but also of the external regulatory environment. At a certain level, the regulatory environment intensifies the effect on employment of minimum wage regulation. Empirical studies based on survey data from 439 enterprises in Guangdong and Fujian show that minimum wage rises had a greater impact on the employment of rural migrant workers in 2008 than in 2007, although no significant change was observed among workers who were permanent urban residents. Further analysis shows that the greater impact on migrant workers derives mainly from the strengthened regulatory environment brought about by the Employment Contracts Law. The permanent urban workforce has not been similarly affected because their interests have been given priority under the dual employment system. This reminds us that the employment effects of the Employment Contracts Law may be realized indirectly through other regulatory measures, including strengthened minimum wage regulation.
基金Project (No. 50607016) supported by the National Natural ScienceFoundation of China
文摘We propose a novel kind of compound permanent magnet synchronous machine (CPMSM), which is applicable in low-speed and high-torque situations. We first explain the structure of the CPMSM. Based on theoretically deducing the calculation formulae of the CPMSM electromagnetic parameters, we analyze the operating characteristics of the CPMSM, and obtain the power-angle curves and working curves. The no-load magnetic field distribution and the cogging torque are analyzed by applying the finite element method of three-dimensional (3D) magnetic fields, to determine the no-load leakage coefficient and the waveform of the cogging torque. Furthermore, the optimal parameters of the permanent magnet for reducing the cogging torque are determined. An important application target of the CPMSM is in directdrive pumping units. We have installed and tested a direct- drive pumping unit in an existing oil well. Test results show that the power consumption of the direct-drive pumping unit driven by CPMSM is 61.1% of that of the beam-pumping unit, and that the floor space and weight are only 50% of those of a beam-pumping unit. The noise output does not exceed 58 dB in a range of 1 m around the machine when the machine is 1.5 m from the ground.
