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ObjectiveTo establish a diatom database by analyzing the quatity, species distribution and differences of diatom in water samples of the whole navigable sections of the Beijing-Hangzhou Grand Canal， to provide a reference for the inference of the drowning site.MethodsWater samples were collected at 22 sites in the navigable sections of the Beijing-Hangzhou Grand Canal （Jining section to Yangzhou Section）， and the diatoms at each site were qualitatively and quantitatively analyzed by using graphite digestion-scanning electron microscopy.ResultsSampling site T （Laohuaijiang River Line, Gaoyou City, Yangzhou City, Jiangsu Province） had the highest number of diatoms, while sampling site O （Siyang County, Suqian City, Jiangsu Province） had the lowest number of diatoms, with a large gap of 68 times. At sampling site Q （Jiangpu District, Huaian city, Jiangsu Province）, there were 19 species of diatoms. The sampling site O had the least diatoms, with 7 species. There were no significant differences in species evenness and species diversity at each sampling site （P>0.05）. Some sampling sites have characterized diatoms, such as Caloneis at station A （Taibai Lake, Weishan County, Shandong Province）, Rhoicosphenia at station B （Nanyang Town, Weishan County, Shandong Province）, Amphora at station I （Taierzhuang District, Zaozhuang City, Shandong Province） and Epithemia at station J （Pizhou 310 national highway, Xuzhou City, Jiangsu Province）.ConclusionThe species richness of diatoms gradually increased from north to south. Diatom species richness and species diversity might be higher in areas with complex environments and large population flow. Climate type has a certain influence on the distribution of diatoms.

At low or zero speed,sensorless control of interior permanent magnet synchronous machines ( IPMSM) can be achieved using the difference between d-and q-axis inductances based on high frequency voltage injection. The d-and q-axis inductances are changed caused by the stator currents variation, and then the accuracy of the rotor position estimation is affected by the changing inductances. A rotor position estimation method based on PWM carrier frequency component was presented. Taking the 12-slot- 10-pole IPMSM prototype as an example,the influence of the saturation saliency and cross coupling saliency on inductance parameters and the position estimation were investigated. The IPMSM model was established considering magnetic saturation and cross coupling saliency,and then the system simulation model and experimental platform were built. The simulation and experimental results prove the correctness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

The author found a novel yellow-white flower color mutation in the male sterile progenies derived from a commercial Brassica.napus hybrid C022, which was produced by a male sterility line 9012A, whose sterility was controlled by interaction between two pairs recessive genes and a pair of epitatic genes. The mutant was named 991S. 991S had three morphologic characters:(1) The color in the middle of every petal was yellow, yet the both sides were white.(2)Every calyx might become striped albino (3) Only male sterile plants in different populations had mutative character. Except flower color, they had similar morphologic characters to the normal male sterile sib-plants. The plants were slender and little with little flowers that had flat petals, bended stigmas, degenerative stamen, and dry anthers. Primary analysis of its origin and inheritance showed that this mutative character was controlled by recessive partial albino gene.