Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shangh...Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shanghai was conducted to test the method for catchments health assessment in urbanized fiver network area. Seven indicators that described four dimensions of river, river network, land use and function, and local feature were used to assess catchments values; while possible change rate of urbanization and industrialization in the next 3 years were chosen for catchments pressure assessment in the value-pressure model. Factors related to catchments classification, indicators measurement and protection priority have been considered in the development strategies for catchments health management. The results showed that value-pressure assessment was applicable in urbanized catchments health management, particularly when both human and catchments had multiple demands. As a result of over 30-year rapid urbanization, more than 70% of Shanghai fiver network area was still in a healthy condition with high catchments values, among them, 39.3% was under high pressure. Poor water quality, simplified river system and weakened local feature of fiver pattern had largely affected catchments health in Shanghai. Lack of long-term monitoring data would seriously restrict the development and validity of catchments health assessment.展开更多
The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces...The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site （GMS） between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred.展开更多
基金Under the auspices of Shanghai Natural Science Foundation (No. 09ZR1409100)National Natural Science Foundation of China (No. 40871016)Key Program of National Natural Science Foundation of China (No. 40730526)
文摘Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shanghai was conducted to test the method for catchments health assessment in urbanized fiver network area. Seven indicators that described four dimensions of river, river network, land use and function, and local feature were used to assess catchments values; while possible change rate of urbanization and industrialization in the next 3 years were chosen for catchments pressure assessment in the value-pressure model. Factors related to catchments classification, indicators measurement and protection priority have been considered in the development strategies for catchments health management. The results showed that value-pressure assessment was applicable in urbanized catchments health management, particularly when both human and catchments had multiple demands. As a result of over 30-year rapid urbanization, more than 70% of Shanghai fiver network area was still in a healthy condition with high catchments values, among them, 39.3% was under high pressure. Poor water quality, simplified river system and weakened local feature of fiver pattern had largely affected catchments health in Shanghai. Lack of long-term monitoring data would seriously restrict the development and validity of catchments health assessment.
基金supported from the National Natural Science Foundation of China (Grant No. 1171088)the National Basic Research Program of China (Grant No. 12CB619403) from Chinese Ministry of Science and Technology
文摘The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site （GMS） between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred.
