Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources...Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources: China's Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per pixel agreement between any 2 of 3 maps was between 38.0%—51.4%; the per pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinary efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.展开更多
A cDNA library was created from stem apex tissue from Jonathan apples (Malus domestica Borkh.), harvested in June to August, during which the plant transitions from vegetative growth to reproductive growth. From this ...A cDNA library was created from stem apex tissue from Jonathan apples (Malus domestica Borkh.), harvested in June to August, during which the plant transitions from vegetative growth to reproductive growth. From this library, we isolated an expressed sequence tag (EST) sequence containing a zinc finger motif, using this sequence, a 779 bp cDNA fragment was obtained by using 5' RACE, and a final full-length cDNA encoding an apple zinc finger protein (named MdZF1; GenBank accession number AB116545) was obtained by further PCR. This zinc finger motif of MdZF1 has high homology with INOETERMINATE1 (ID1) gene from maize which seemed to be involved in the transition to flowering. Northern blot and RT-PCR analyses showed that the MdZF1 expressed in the root, stem, leaves, shoot apex and floral organs of the apple, with expression levels higher in root, stem, leaves and floral shoot apex than that in floral organs (sepals, petals, stamens and pistils). Genomic Southern analysis showed that there was a single copy gene in apple genome.展开更多
One developing commercial vehicle was simulated on crashworthiness using the nonlinear finite element method. The deformation of the auto-body, the movement of the steering wheel and the dynamic responses of the occup...One developing commercial vehicle was simulated on crashworthiness using the nonlinear finite element method. The deformation of the auto-body, the movement of the steering wheel and the dynamic responses of the occupant at the initial velocity of 50 km/h were studied. The results show that the design of the vehicle could be improved on structure and material. The frontal longitudinal beam, the main energy-absorbing part of the auto-body, was optimized on structure. The data of the simulation predict that the hinge of the engine hood would fracture during the crash. The failure of the engine hood hinge would be a danger to both the driver and passengers. Then the problem was solved by changing the engine hood and hinge on structure and material. Simulation results also show that applying new material and new manufacture techniques could improve the crashworthiness of the vehicle greatly. These improvement methods are valuable to the virtual design of vehicles.展开更多
Music teaching in primary schools has certain difficulties. In order to realize students' autonomous learning, it is necessary to cultivate students' singing habits in an all-round way so that they can learn m...Music teaching in primary schools has certain difficulties. In order to realize students' autonomous learning, it is necessary to cultivate students' singing habits in an all-round way so that they can learn music with teachers in class and make the music learning atmosphere more relaxed. Learning music requires a cheerful mood. In terms of habit formation, teachers need to actively guide so that students can focus on music learning, so that they can naturally develop music habits and ensure the smooth development of primary school music lessons.展开更多
A Bayesian high-resolution direction-of-arrival (DOA) estimator is proposed based on the maximum a posteriori principle. The statistical performance of the Bayesian high-resolution DOA estimator is also investigated. ...A Bayesian high-resolution direction-of-arrival (DOA) estimator is proposed based on the maximum a posteriori principle. The statistical performance of the Bayesian high-resolution DOA estimator is also investigated. Comparison with MUSIC and Maximum likelihood estimator (MLE) shows that the Bayesian method has higher resolution and more accurate estimates for either incoherent or coherent sources. It is also more robust in the case of low SNR.展开更多
文摘Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources: China's Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per pixel agreement between any 2 of 3 maps was between 38.0%—51.4%; the per pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinary efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.
文摘A cDNA library was created from stem apex tissue from Jonathan apples (Malus domestica Borkh.), harvested in June to August, during which the plant transitions from vegetative growth to reproductive growth. From this library, we isolated an expressed sequence tag (EST) sequence containing a zinc finger motif, using this sequence, a 779 bp cDNA fragment was obtained by using 5' RACE, and a final full-length cDNA encoding an apple zinc finger protein (named MdZF1; GenBank accession number AB116545) was obtained by further PCR. This zinc finger motif of MdZF1 has high homology with INOETERMINATE1 (ID1) gene from maize which seemed to be involved in the transition to flowering. Northern blot and RT-PCR analyses showed that the MdZF1 expressed in the root, stem, leaves, shoot apex and floral organs of the apple, with expression levels higher in root, stem, leaves and floral shoot apex than that in floral organs (sepals, petals, stamens and pistils). Genomic Southern analysis showed that there was a single copy gene in apple genome.
文摘One developing commercial vehicle was simulated on crashworthiness using the nonlinear finite element method. The deformation of the auto-body, the movement of the steering wheel and the dynamic responses of the occupant at the initial velocity of 50 km/h were studied. The results show that the design of the vehicle could be improved on structure and material. The frontal longitudinal beam, the main energy-absorbing part of the auto-body, was optimized on structure. The data of the simulation predict that the hinge of the engine hood would fracture during the crash. The failure of the engine hood hinge would be a danger to both the driver and passengers. Then the problem was solved by changing the engine hood and hinge on structure and material. Simulation results also show that applying new material and new manufacture techniques could improve the crashworthiness of the vehicle greatly. These improvement methods are valuable to the virtual design of vehicles.
文摘Music teaching in primary schools has certain difficulties. In order to realize students' autonomous learning, it is necessary to cultivate students' singing habits in an all-round way so that they can learn music with teachers in class and make the music learning atmosphere more relaxed. Learning music requires a cheerful mood. In terms of habit formation, teachers need to actively guide so that students can focus on music learning, so that they can naturally develop music habits and ensure the smooth development of primary school music lessons.
基金This work was supported by the National Natural Science Foundation of China (60272076) and Doctoral Discipline Foundation.
文摘A Bayesian high-resolution direction-of-arrival (DOA) estimator is proposed based on the maximum a posteriori principle. The statistical performance of the Bayesian high-resolution DOA estimator is also investigated. Comparison with MUSIC and Maximum likelihood estimator (MLE) shows that the Bayesian method has higher resolution and more accurate estimates for either incoherent or coherent sources. It is also more robust in the case of low SNR.
