With the impoundment of the Three Gorges Reservoir, algal blooms have been found in some tributaries. In this study, according to the theoretical analysis of the eutrophication mechanism in a river-type reservoir trib...With the impoundment of the Three Gorges Reservoir, algal blooms have been found in some tributaries. In this study, according to the theoretical analysis of the eutrophication mechanism in a river-type reservoir tributary, a one-dimensional eutrophication model was developed for the Xiangxi River tributary of the Three Gorges Reservoir, and the influence of hydrodynamic conditions on the primary growth rate of algae was investigated. Furthermore, numerical predictions of hydraulic variables and eutrophication factors, such as the concentration distribution of TP, TN, and Chl-a in the spatial and temporal domains, were carried out. Comparison of computation results of TP, TN, and Chl-a concentrations along the river in the spring of 2005 with experimental data demonstrates the validity of the model. The agreement between the computation results and the experimental data of TP and TN concentrations is better than the agreement between those of Chl-a concentration. The simulated results also show that the Chl-a concentration downstream is much higher than that in the upstream tributary, which potentially indicates the outbreak of algae in this area. Therefore, this study provides a feasible method of accurately predicting the state of eutrophication in river-type reservoirs and their tributaries.展开更多
Focusing on the region of Yarlung Zangbo River and the middle reaches of itstwo tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the 'One Riverand Two Tributaries' region), and b...Focusing on the region of Yarlung Zangbo River and the middle reaches of itstwo tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the 'One Riverand Two Tributaries' region), and based on the data from China 3rd, 4th and5th population censuses,the article has analyzed change patterns of this region' s labor force. Major findings from thestudy are summarized as follows; (1) Compared with the data from the 3rd census, labor forcepopulation in 2000 has increased significantly. (2) Children dependency coefficient has dropped,while old people dependency coefficient has changed very slightly with an increase of 0. 047% only.(3) Compared 2000 with 1982, illiteracy and semi-illiteracy rate of the population above 15 yearsold have decreased significantly by 30. 69 percentage points, but still higher than the nationalaverage. (4) Women' s illiteracy rate has dropped faster than men's, but up to 2000 it was generallyquite high. The upgrading of the entire population's overall quality has a long way to go.展开更多
Focusing on the 18 counties along “One River and Two Tributaries” region, and based on the data from China 3nl, 4th and 5th population censuses, this article has analyzed the time and spatial changing patterns of th...Focusing on the 18 counties along “One River and Two Tributaries” region, and based on the data from China 3nl, 4th and 5th population censuses, this article has analyzed the time and spatial changing patterns of the population in this region. The analyses show that since the 3nl population census, total population, average age and total birth rate have all changed considerably: ① Total population has grown, fast, with most counties' annual average growth rate of more than 10. ② In terms of the region's average age, in 2000 the age in the 18 counties is younger than 30 years old. ③ Compared with the 3nl population census, labor force by the 5th census is much younger. ④ Countermeasures are proposed to control population by controlling birth rate as the result of the local resident's quality improvement by education.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50779028)the National Science and Technology Supporting Plan (Grant No. 2008BAB29B09)
文摘With the impoundment of the Three Gorges Reservoir, algal blooms have been found in some tributaries. In this study, according to the theoretical analysis of the eutrophication mechanism in a river-type reservoir tributary, a one-dimensional eutrophication model was developed for the Xiangxi River tributary of the Three Gorges Reservoir, and the influence of hydrodynamic conditions on the primary growth rate of algae was investigated. Furthermore, numerical predictions of hydraulic variables and eutrophication factors, such as the concentration distribution of TP, TN, and Chl-a in the spatial and temporal domains, were carried out. Comparison of computation results of TP, TN, and Chl-a concentrations along the river in the spring of 2005 with experimental data demonstrates the validity of the model. The agreement between the computation results and the experimental data of TP and TN concentrations is better than the agreement between those of Chl-a concentration. The simulated results also show that the Chl-a concentration downstream is much higher than that in the upstream tributary, which potentially indicates the outbreak of algae in this area. Therefore, this study provides a feasible method of accurately predicting the state of eutrophication in river-type reservoirs and their tributaries.
文摘Focusing on the region of Yarlung Zangbo River and the middle reaches of itstwo tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the 'One Riverand Two Tributaries' region), and based on the data from China 3rd, 4th and5th population censuses,the article has analyzed change patterns of this region' s labor force. Major findings from thestudy are summarized as follows; (1) Compared with the data from the 3rd census, labor forcepopulation in 2000 has increased significantly. (2) Children dependency coefficient has dropped,while old people dependency coefficient has changed very slightly with an increase of 0. 047% only.(3) Compared 2000 with 1982, illiteracy and semi-illiteracy rate of the population above 15 yearsold have decreased significantly by 30. 69 percentage points, but still higher than the nationalaverage. (4) Women' s illiteracy rate has dropped faster than men's, but up to 2000 it was generallyquite high. The upgrading of the entire population's overall quality has a long way to go.
文摘Focusing on the 18 counties along “One River and Two Tributaries” region, and based on the data from China 3nl, 4th and 5th population censuses, this article has analyzed the time and spatial changing patterns of the population in this region. The analyses show that since the 3nl population census, total population, average age and total birth rate have all changed considerably: ① Total population has grown, fast, with most counties' annual average growth rate of more than 10. ② In terms of the region's average age, in 2000 the age in the 18 counties is younger than 30 years old. ③ Compared with the 3nl population census, labor force by the 5th census is much younger. ④ Countermeasures are proposed to control population by controlling birth rate as the result of the local resident's quality improvement by education.
