Under the assumptions of triangular cross section channel and uniform stable flow, an analytical solution of the minimum ecological in-stream flow requirement （MEIFR） is deduced. Based on the analytical solution, th...Under the assumptions of triangular cross section channel and uniform stable flow, an analytical solution of the minimum ecological in-stream flow requirement （MEIFR） is deduced. Based on the analytical solution, the uncertainty of the wetted perimeter method is analyzed by comparing the two techniques for the determination of the critical point on the relationship curve between wetted perimeter, P and discharge, Q. It is clearly shown that the results of MEIFR based on curvature technique （corresponding to the maximum curvature） and slope technique （slope being 1） are significantly different. On the P-Q curve, the slope of the critical point with the maximum curvature is 0.39 and the MEIFR varied prominently with the change of the slope threshold. This indicates that if a certain value of the slope threshold is not available for slope technique, curvature technique may be a better choice. By applying the analytical solution of MEIFR in the losing rivers of the Western Route South-to-North Water Transfer Project in China, the MEIFR value via curvature technique is 2.5%-23.7% of the multi-year average annual discharge, while that for slope technique is 11%-105.7%. General conclusions would rely on the more detailed research for all kinds of cross-sections.展开更多
In the 1960s and 1970s-as strncturalism, post-structuralism, and literary criticism seeped into history--the ＂linguistic turn＂ or ＂narrative turn,＂ leading to what is known as postmodem philosophy of history, took...In the 1960s and 1970s-as strncturalism, post-structuralism, and literary criticism seeped into history--the ＂linguistic turn＂ or ＂narrative turn,＂ leading to what is known as postmodem philosophy of history, took place in Western philosophy of history. In the past forty years of reform and opening up to the outside world, and especially in the most recent two or three decades, Chinese research on Western postmodem philosophy of history has proceeded from overall review to in-depth research, and then on to reflection, criticism, and even transcendence. Neither the rethinking of historical objectivity and rationality nor the reconstruction of convictions about historical reason can work without the profound insights or theoretical tensions of postmodern philosophy of history.展开更多
As the symbol of China’s feudal reign during the Ming and Qing dynasties (1368-1911),Beijing’s Forbidden City rep-resents all that is rich and cre-ative about China’s history andancient archi-
AS the Chinese saying goes, "Ask for local custom when you enter a foreign country." Western food’s first introduction to China in the 17th century was accompanied with its adoption to Chinese dining habits...AS the Chinese saying goes, "Ask for local custom when you enter a foreign country." Western food’s first introduction to China in the 17th century was accompanied with its adoption to Chinese dining habits. Western food was introduced into China in large scale during the mid-19th and early 20th centuries. However, as early as the 17th century Western missionaries and envoys were introducing food from their homeland to upper-class Chinese as a means of paying tribute展开更多
基金National Natural Science Foundation of China, No. 90211007 No.50279049+1 种基金 Knowledge Innovation Project of IGSNRR, CAS, No.CXIOG-A04-12 No.CX10G-E01-08
文摘Under the assumptions of triangular cross section channel and uniform stable flow, an analytical solution of the minimum ecological in-stream flow requirement （MEIFR） is deduced. Based on the analytical solution, the uncertainty of the wetted perimeter method is analyzed by comparing the two techniques for the determination of the critical point on the relationship curve between wetted perimeter, P and discharge, Q. It is clearly shown that the results of MEIFR based on curvature technique （corresponding to the maximum curvature） and slope technique （slope being 1） are significantly different. On the P-Q curve, the slope of the critical point with the maximum curvature is 0.39 and the MEIFR varied prominently with the change of the slope threshold. This indicates that if a certain value of the slope threshold is not available for slope technique, curvature technique may be a better choice. By applying the analytical solution of MEIFR in the losing rivers of the Western Route South-to-North Water Transfer Project in China, the MEIFR value via curvature technique is 2.5%-23.7% of the multi-year average annual discharge, while that for slope technique is 11%-105.7%. General conclusions would rely on the more detailed research for all kinds of cross-sections.
文摘In the 1960s and 1970s-as strncturalism, post-structuralism, and literary criticism seeped into history--the ＂linguistic turn＂ or ＂narrative turn,＂ leading to what is known as postmodem philosophy of history, took place in Western philosophy of history. In the past forty years of reform and opening up to the outside world, and especially in the most recent two or three decades, Chinese research on Western postmodem philosophy of history has proceeded from overall review to in-depth research, and then on to reflection, criticism, and even transcendence. Neither the rethinking of historical objectivity and rationality nor the reconstruction of convictions about historical reason can work without the profound insights or theoretical tensions of postmodern philosophy of history.
文摘As the symbol of China’s feudal reign during the Ming and Qing dynasties (1368-1911),Beijing’s Forbidden City rep-resents all that is rich and cre-ative about China’s history andancient archi-
文摘AS the Chinese saying goes, "Ask for local custom when you enter a foreign country." Western food’s first introduction to China in the 17th century was accompanied with its adoption to Chinese dining habits. Western food was introduced into China in large scale during the mid-19th and early 20th centuries. However, as early as the 17th century Western missionaries and envoys were introducing food from their homeland to upper-class Chinese as a means of paying tribute
