In order to increase the efficiency and reliability of the dynamic analysis for flexible planar linkage containing the coupling of multi-energy domains, a method based on bond graph is introduced. From the viewpoint o...In order to increase the efficiency and reliability of the dynamic analysis for flexible planar linkage containing the coupling of multi-energy domains, a method based on bond graph is introduced. From the viewpoint of power conservation, the peculiar property of bond graph multiport element MTF is discussed. The procedure of modeling planar flexible muhibody mechanical systems by bond graphs and its dynamic principle are deseribed. To overcome the algebraic difficulty brought by differential causality anti nonlinear junction structure, the constraint forces at joints can be considered as unknown effort sources and added to the corresponding O-junctions of system bond graph model. As a result, the automatic modeling on a computer is realized. The validity of the procedure is illustrated by a practical example.展开更多
Combined with practical engineering, based on the introduction of soil arching theory, we explore the impact of barrier piles in blind sheet-pile bank connecting structure. Besides, we build a plane strain model by AB...Combined with practical engineering, based on the introduction of soil arching theory, we explore the impact of barrier piles in blind sheet-pile bank connecting structure. Besides, we build a plane strain model by ABAQUS sot＇cware to study the impact of cross section type, the pile spacing and soil properties on soil arching effect. We find that cross section type of the pile has a certain influence on soil stress distribution in front of the barrier piles by comparing circular cross section and rectangular cross section. We also find that clear distance between the barrier piles and cohesive force of the soil have a great influence on that impact. We can increase clear distance between the barrier piles appropriately to improve the efficiency of construction and reduce the proiect cost.展开更多
The sea surface height anomaly(SSHA) signals leading the fall Indian Ocean Dipole(IOD) are investigated. The results suggest that, prior to the IOD by one year, a positive SSHA emerges over the western-central tropica...The sea surface height anomaly(SSHA) signals leading the fall Indian Ocean Dipole(IOD) are investigated. The results suggest that, prior to the IOD by one year, a positive SSHA emerges over the western-central tropical Pacific(WCTP), which peaks during winter(January-February-March, JFM), persists into late spring and early summer(April-May-June, AMJ), and becomes weakened later on. An SSHA index, referred as to SSHA_WCTP, is defined as the averaged SSHA over the WCTP during JFM. The index is not only significantly positively correlated with the following-fall(September-October-November, SON) IOD index, but also is higher than the autocorrelation of the IOD index crossing the two different seasons. The connection of SSHA_ WCTP with following-summer rainfall in China is then explored. The results suggest that higher(lower) SSHA_ WCTP corresponds to increased(reduced) rainfall over southern coastal China, along with suppressed(increased) rainfall over the middle–lower reaches of the Yangtze River, North China, and the Xinjiang region of northwestern China. Mechanistically, following the preceding-winter higher(lower) SSHA_WCTP, the South Asia High and the Western Pacific Subtropical High are weakened(intensified), which results in the East Asian summer monsoon weakening(intensifying). Finally, the connection between SSHA_WCTP and El Ni?o-Southern Oscillation(ENSO) is analyzed. Despite a significant correlation, SSHA_WCTP is more closely connected with summer rainfall. This implies that the SSHA_WCTP index in the preceding winter is a more effective predictor of summer rainfall in comparison with ENSO.展开更多
A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigon...A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigonal planar ligand, which links three di-copper paddlewheel units giving rise to a Pt304 net.展开更多
文摘In order to increase the efficiency and reliability of the dynamic analysis for flexible planar linkage containing the coupling of multi-energy domains, a method based on bond graph is introduced. From the viewpoint of power conservation, the peculiar property of bond graph multiport element MTF is discussed. The procedure of modeling planar flexible muhibody mechanical systems by bond graphs and its dynamic principle are deseribed. To overcome the algebraic difficulty brought by differential causality anti nonlinear junction structure, the constraint forces at joints can be considered as unknown effort sources and added to the corresponding O-junctions of system bond graph model. As a result, the automatic modeling on a computer is realized. The validity of the procedure is illustrated by a practical example.
文摘Combined with practical engineering, based on the introduction of soil arching theory, we explore the impact of barrier piles in blind sheet-pile bank connecting structure. Besides, we build a plane strain model by ABAQUS sot＇cware to study the impact of cross section type, the pile spacing and soil properties on soil arching effect. We find that cross section type of the pile has a certain influence on soil stress distribution in front of the barrier piles by comparing circular cross section and rectangular cross section. We also find that clear distance between the barrier piles and cohesive force of the soil have a great influence on that impact. We can increase clear distance between the barrier piles appropriately to improve the efficiency of construction and reduce the proiect cost.
基金jointly supported by the Strategic Project of the Chinese Academy of Sciences(Grant No.XDA11010401)the National Basic Research Program of China(973 Program,Grant Nos.2012CB417403 and 2015CB453202)
文摘The sea surface height anomaly(SSHA) signals leading the fall Indian Ocean Dipole(IOD) are investigated. The results suggest that, prior to the IOD by one year, a positive SSHA emerges over the western-central tropical Pacific(WCTP), which peaks during winter(January-February-March, JFM), persists into late spring and early summer(April-May-June, AMJ), and becomes weakened later on. An SSHA index, referred as to SSHA_WCTP, is defined as the averaged SSHA over the WCTP during JFM. The index is not only significantly positively correlated with the following-fall(September-October-November, SON) IOD index, but also is higher than the autocorrelation of the IOD index crossing the two different seasons. The connection of SSHA_ WCTP with following-summer rainfall in China is then explored. The results suggest that higher(lower) SSHA_ WCTP corresponds to increased(reduced) rainfall over southern coastal China, along with suppressed(increased) rainfall over the middle–lower reaches of the Yangtze River, North China, and the Xinjiang region of northwestern China. Mechanistically, following the preceding-winter higher(lower) SSHA_WCTP, the South Asia High and the Western Pacific Subtropical High are weakened(intensified), which results in the East Asian summer monsoon weakening(intensifying). Finally, the connection between SSHA_WCTP and El Ni?o-Southern Oscillation(ENSO) is analyzed. Despite a significant correlation, SSHA_WCTP is more closely connected with summer rainfall. This implies that the SSHA_WCTP index in the preceding winter is a more effective predictor of summer rainfall in comparison with ENSO.
基金supported by the U.S. Department of Energy (DOE Grants DE-FC36-07GO17033)the Welch Foundation (A-1725)+1 种基金supported by the National Science Foundation/Department of Energy under grant number NSF/CHE-0822838supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
文摘A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigonal planar ligand, which links three di-copper paddlewheel units giving rise to a Pt304 net.
