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Small- and medium-sized ships have a shallow draft, but their propellers are fast in speed, small in diameter and light in weight. Once the span of the front and after stern tube bearings is large, the position of the after stern tube bearing fulcrum will exceed the range given by the standard. Based on the finite element method, the shafting was simplified into Timoshenko beam element to establish a finite element model. Considering the actual installation clearance of the ship shafting and the load stiffness curve calculated based on Hertz contact theory, the shafting alignment calculation of large span propeller shaft, which was based on different support positions and various support models, indicates that for the shafting with a large span of propeller shaft, the value of the fulcrum position of stern tube rear bearing in CB/Z 338-2005 is not suitable. If the bearing fulcrum exactitude is correct, the calculated bearing loads of single point rigid support, single point elastic support and multi-point nonlinear elastic support will have a similar result.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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