In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized it...In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized its social security system accordingly.This paper divides the transition of China’s social security system into seven stages before and after 1978.The traditional social security system was predicated on the dominant public ownership,a highly centralized economy,and“full employment.”It was congruous with the ownership structure,income distribution,and labor systems under the closed economy.The modern social security system is developed to meet the needs of an open economy and promotes economic development by giving play to consumption and investment,facilitating labor flow,and boosting productivity.The modern social security system requires further supply-side structural reforms to promote the high-quality development of the open economy.展开更多
In this letter, a universal receiver structure with modulation classification and syn-chronization recovery for MDPSK signal is presented. The universal timing estimation algorithmfor M-ary DPSK signals is proposed to...In this letter, a universal receiver structure with modulation classification and syn-chronization recovery for MDPSK signal is presented. The universal timing estimation algorithmfor M-ary DPSK signals is proposed to estimate the best symbol timing. An identification algo-rithm based on fourth-order cumulants of signal is used to identify the modulation scheme of thesignal. Numerical results of the performance of the proposed receiver are given.展开更多
According to the action law of gas flow during injecting inert gases as the research main line, and hydromechanics and thermodynamics theories, the characteristic of gas delamination that was caused by injecting inert...According to the action law of gas flow during injecting inert gases as the research main line, and hydromechanics and thermodynamics theories, the characteristic of gas delamination that was caused by injecting inert gases to closed fire zone was analyzed. The criterion was brought forward, which could scale disappearing probability of turbulent state. Formation mechanism of gas layer in turbulent state was discussed primarily. Simultaneously, the condition was pointed out, which could makc the gas in turbulent state by injecting different gases. The mathematical model about dynamic changes of oxygen and methane concentration in the process of injecting gases was erected. The mixture mechanism about injecting different flow inert gases and flammable gas layer in closed fire zone was revealed.展开更多
Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long spa...Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable stayed bridge are studied. After theoretical analysis, numerical evaluation and practical test, the loading assistant closure method is employed in Edong Yangtze River Bridge. The loading assistant closure method, with better thermal adaptability and less influence on bridge line and the forced status, can meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable stayed bridges. The conclusion can provide a reference for the further design of the similar brid^es.展开更多
We propose a novel all-optical buffer and shaper based on the adjustable power transferring characteristics of the complex-modulated long-period-grating coupler(CM-LPGC)and the multiple circulations of the self-closed...We propose a novel all-optical buffer and shaper based on the adjustable power transferring characteristics of the complex-modulated long-period-grating coupler(CM-LPGC)and the multiple circulations of the self-closed fiber loop.By turning on the external optical pumps,the signals can be stored by utilizing the nonreciprocal power transferring of the CM-LPGC.When the buffer time is satisfied,the signals can be extracted discretionarily by turning off the external optical pumps.In addition,by controlling the spectral bandwidth of the CM-LPGC,the temporal rectangular pulse can be obtained by re-shaping the Gaussian input signal.展开更多
文摘In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized its social security system accordingly.This paper divides the transition of China’s social security system into seven stages before and after 1978.The traditional social security system was predicated on the dominant public ownership,a highly centralized economy,and“full employment.”It was congruous with the ownership structure,income distribution,and labor systems under the closed economy.The modern social security system is developed to meet the needs of an open economy and promotes economic development by giving play to consumption and investment,facilitating labor flow,and boosting productivity.The modern social security system requires further supply-side structural reforms to promote the high-quality development of the open economy.
基金Partly supported by the National Natural Science Foundation of China under contract No.69872028,National"863" Program of China under contract No.2001AA123031 and Teaching & Research Award Program for Outstanding Young Teachers in Higher Education Inst
文摘In this letter, a universal receiver structure with modulation classification and syn-chronization recovery for MDPSK signal is presented. The universal timing estimation algorithmfor M-ary DPSK signals is proposed to estimate the best symbol timing. An identification algo-rithm based on fourth-order cumulants of signal is used to identify the modulation scheme of thesignal. Numerical results of the performance of the proposed receiver are given.
文摘According to the action law of gas flow during injecting inert gases as the research main line, and hydromechanics and thermodynamics theories, the characteristic of gas delamination that was caused by injecting inert gases to closed fire zone was analyzed. The criterion was brought forward, which could scale disappearing probability of turbulent state. Formation mechanism of gas layer in turbulent state was discussed primarily. Simultaneously, the condition was pointed out, which could makc the gas in turbulent state by injecting different gases. The mathematical model about dynamic changes of oxygen and methane concentration in the process of injecting gases was erected. The mixture mechanism about injecting different flow inert gases and flammable gas layer in closed fire zone was revealed.
文摘Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable stayed bridge are studied. After theoretical analysis, numerical evaluation and practical test, the loading assistant closure method is employed in Edong Yangtze River Bridge. The loading assistant closure method, with better thermal adaptability and less influence on bridge line and the forced status, can meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable stayed bridges. The conclusion can provide a reference for the further design of the similar brid^es.
基金supported by the National Natural Science Foundation of China(Nos.61007007,11002018and61101110)
文摘We propose a novel all-optical buffer and shaper based on the adjustable power transferring characteristics of the complex-modulated long-period-grating coupler(CM-LPGC)and the multiple circulations of the self-closed fiber loop.By turning on the external optical pumps,the signals can be stored by utilizing the nonreciprocal power transferring of the CM-LPGC.When the buffer time is satisfied,the signals can be extracted discretionarily by turning off the external optical pumps.In addition,by controlling the spectral bandwidth of the CM-LPGC,the temporal rectangular pulse can be obtained by re-shaping the Gaussian input signal.
