The eco-environmental restoration has been a chief task of the western development strategies carried out by the central and local governments of China since the late 1990s, and the ecological de-farming has been rega...The eco-environmental restoration has been a chief task of the western development strategies carried out by the central and local governments of China since the late 1990s, and the ecological de-farming has been regarded as a powerful measure for the ecological restoration in the Loess Plateau and the upper reaches of the Yangtze River. "Relieving and de-farming" (RD) and "rebuilding terrace and de-farming" (RTD) are two more mature ones among various de-farming modes. Taking the loess hilly-gully region as a case, this paper summarized the basic characteristics of RD and RTD modes, calculated the sizes of de-farming slope farmland, rebuilt terraces, enlarged garden plots and restored vegetation, and compared the differences of two modes in terms of de-farming area, ecological reestablishment index, investment demand amount and benefits. The results showed that RTD mode has many advantages, including suitable investment, sufficient grain supply and great benefits, and will be the best ecological reestablishment mode in the loess hilly-gully region, and RD mode which is being carried out in this region should be replaced by RTD mode as soon as possible.展开更多
We compare three different methods to extract coherent modes from Doppler backscattering （DBS）, which are center of gravity （COG） of the complex amplitude spectrum, spectrum of DBS phase derivative （phase derivat...We compare three different methods to extract coherent modes from Doppler backscattering （DBS）, which are center of gravity （COG） of the complex amplitude spectrum, spectrum of DBS phase derivative （phase derivative method）, and phase spectrum, respectively. These three methods are all feasible to extract coherent modes, for example, geodesic acoustic mode oscillation. However, there are stilI differences between dealing with high frequency modes （several hundred kHz） and low frequency modes, （several kHz） hiding in DBS signal. There is a significant amount of power at low frequencies in the phase spectrum, which can be removed by using the phase derivative method and COG. High frequency modes are clearer by using the COO and the phase derivative method than the phase spectrum. The spectrum of DBS amplitude does not show the coherent modes detected by using COG, phase derivative method and phase spectrum. When two Doppler shifted peaks exist, coherent modes and their harmonics appear in the spectrum of DBS amplitude, which are introduced by the DBS phase.展开更多
This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system...This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system in science and technology in China. The countermeasures are proposed with a hope to shorten China's and US's gap of agricultural innovation in science and technology by analyzing agricultural innovation model features in science and technology of the United States. The advantages of United States model of agricultural innovation in science and technology include sound legal framework safeguard, complete scientific and technological innovation system, high quality and talented personnel, sufficient technical development and extension funding, and extensive applications of modern agricultural high-tech. There is a gap in agricultural innovation between China and the United States. Agriculture innovation in science and technology in China should improve in several aspects such as agricultural legislation, construction of sound agricultural innovation system in science and technology, building first-class agricultural innovation and extension teams, establishing diversified channels for investment, and improving the applications of high technology in agriculture.展开更多
基金National Natural Science Foundation of China No.40371051+1 种基金 Knowledge Innovation Project of Chinese Academy of Sciences No.KZCX1-6-2-6
文摘The eco-environmental restoration has been a chief task of the western development strategies carried out by the central and local governments of China since the late 1990s, and the ecological de-farming has been regarded as a powerful measure for the ecological restoration in the Loess Plateau and the upper reaches of the Yangtze River. "Relieving and de-farming" (RD) and "rebuilding terrace and de-farming" (RTD) are two more mature ones among various de-farming modes. Taking the loess hilly-gully region as a case, this paper summarized the basic characteristics of RD and RTD modes, calculated the sizes of de-farming slope farmland, rebuilt terraces, enlarged garden plots and restored vegetation, and compared the differences of two modes in terms of de-farming area, ecological reestablishment index, investment demand amount and benefits. The results showed that RTD mode has many advantages, including suitable investment, sufficient grain supply and great benefits, and will be the best ecological reestablishment mode in the loess hilly-gully region, and RD mode which is being carried out in this region should be replaced by RTD mode as soon as possible.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10990210 and 11475173the National Magnetic Confinement Fusion Energy Program of China under Grant Nos 2013GB106002 and 2014GB109002
文摘We compare three different methods to extract coherent modes from Doppler backscattering （DBS）, which are center of gravity （COG） of the complex amplitude spectrum, spectrum of DBS phase derivative （phase derivative method）, and phase spectrum, respectively. These three methods are all feasible to extract coherent modes, for example, geodesic acoustic mode oscillation. However, there are stilI differences between dealing with high frequency modes （several hundred kHz） and low frequency modes, （several kHz） hiding in DBS signal. There is a significant amount of power at low frequencies in the phase spectrum, which can be removed by using the phase derivative method and COG. High frequency modes are clearer by using the COO and the phase derivative method than the phase spectrum. The spectrum of DBS amplitude does not show the coherent modes detected by using COG, phase derivative method and phase spectrum. When two Doppler shifted peaks exist, coherent modes and their harmonics appear in the spectrum of DBS amplitude, which are introduced by the DBS phase.
基金Supported by Jiangsu Overseas Research&Training Program for University Prominent Young&Middle-aged Teachers and Presidents(2011)Jiangsu Province"333"High-level Talents Program(2011)University Philosophical and Social Science Research Program of the Education Department in Jiangsu Province in 2010(2010SJD630050)
文摘This research was conducted to provide a comparative analysis of China's and US's agricultural innovation in science and technology and offer some guidance on the construction of agricultural innovation system in science and technology in China. The countermeasures are proposed with a hope to shorten China's and US's gap of agricultural innovation in science and technology by analyzing agricultural innovation model features in science and technology of the United States. The advantages of United States model of agricultural innovation in science and technology include sound legal framework safeguard, complete scientific and technological innovation system, high quality and talented personnel, sufficient technical development and extension funding, and extensive applications of modern agricultural high-tech. There is a gap in agricultural innovation between China and the United States. Agriculture innovation in science and technology in China should improve in several aspects such as agricultural legislation, construction of sound agricultural innovation system in science and technology, building first-class agricultural innovation and extension teams, establishing diversified channels for investment, and improving the applications of high technology in agriculture.
