河道内鱼类上溯路径不唯一,聚集位置更是难以预测,对鱼类上溯行为进行有效引导有助于提升过鱼设施进口的效率。为此,该研究提出了一种导鱼堰的概念和设计方法,结合姚家坪水电站的过鱼设施,利用流场三维数值模拟、鱼类洄游(active fish m...河道内鱼类上溯路径不唯一,聚集位置更是难以预测,对鱼类上溯行为进行有效引导有助于提升过鱼设施进口的效率。为此,该研究提出了一种导鱼堰的概念和设计方法,结合姚家坪水电站的过鱼设施,利用流场三维数值模拟、鱼类洄游(active fish migration,AFM)模型和实鱼试验对导鱼堰的效果进行评估。结果表明:姚家平水利枢纽工程的导鱼堰上下游水面落差为0.36~0.40 m,过堰水流流速可达1.5~2.8 m/s,形成阻鱼的屏障,并在导鱼堰下游侧形成了诱导鱼类向集鱼渠进鱼口游动的唯一低流速上溯通道,鱼类聚集点趋于唯一,验证了导鱼堰方案的合理性。利用鱼类洄游模型对导鱼堰的导鱼效果进行预测,结果表明,下游高水位和低水位2种工况下,90%以上的鱼类游动路径均表现出相似的规律,鱼类沿河道右岸和导鱼堰下游侧的低流速通道上溯,并最终聚集在集鱼渠的进鱼口处。放鱼试验中试验个体全部进入集鱼渠,结果进一步证实导鱼堰可以有效引导鱼类游动路线,并在集鱼渠进鱼口处形成唯一的聚集区。本文提出的导鱼堰丰富了生态水工建筑物的形式,可为过鱼设施进口的水力设计及下游河道的局部整治提供参考。展开更多
针对当前考虑弹药消耗多重影响因素所反映的规律不够客观,长时间弹药消耗没有考虑其消耗规律等问题,提出了利用长短期记忆神经网络(long short term memory,LSTM)来分析弹药消耗的规律。通过示例数据的训练集和测试集,来进行弹药消耗的...针对当前考虑弹药消耗多重影响因素所反映的规律不够客观,长时间弹药消耗没有考虑其消耗规律等问题,提出了利用长短期记忆神经网络(long short term memory,LSTM)来分析弹药消耗的规律。通过示例数据的训练集和测试集,来进行弹药消耗的预测。通过对比RNN模型和BP神经网络模型在测试集上的平均绝对误差(mean absolute error,MAE)和均根方差(root mean square error,RMSE),LSTM神经网络在MAE和RMSE上的误差小,对于长时间序列弹药消耗数据有着很好的预测效果。展开更多
A new large-bodied theropod dinosaur, Datanglong guangxiensis gen. et sp. nov., was recovered from the Lower Cretaceous Xinlong Formation of the Datang Basin, Guangxi. It is unique in several features including： post...A new large-bodied theropod dinosaur, Datanglong guangxiensis gen. et sp. nov., was recovered from the Lower Cretaceous Xinlong Formation of the Datang Basin, Guangxi. It is unique in several features including： posteriormost dorsal vertebra with teardrop-shaped pneumatic foramen confined by enlarged pcdl, acpl and the centrum; posteriormost dorsal with well-developed, horizontal prpl; posteriormost dorsal with a parapophysis projecting more laterally than the diapophysis; brevis fossa shallow with short, ridge-like medial blade; and iliac pubic peduncle with posteroventrally expanded margin. Cladistic analysis supports the idea that this new taxon Datanglong guangxiensis is a primitive member of the Carcharodontosauria in possessing two unambiguous synapomorphies： large external pneumatic foramina and internal spaces present in the lateral surface of ilium, and a peg-and-socket ischiac articulation with the ilium. The presence of the new taxon from Guangxi further confirms that Carcharodontosauria were cosmopolitan large-bodied predators during the Early-mid Cretaceous.展开更多
文摘河道内鱼类上溯路径不唯一,聚集位置更是难以预测,对鱼类上溯行为进行有效引导有助于提升过鱼设施进口的效率。为此,该研究提出了一种导鱼堰的概念和设计方法,结合姚家坪水电站的过鱼设施,利用流场三维数值模拟、鱼类洄游(active fish migration,AFM)模型和实鱼试验对导鱼堰的效果进行评估。结果表明:姚家平水利枢纽工程的导鱼堰上下游水面落差为0.36~0.40 m,过堰水流流速可达1.5~2.8 m/s,形成阻鱼的屏障,并在导鱼堰下游侧形成了诱导鱼类向集鱼渠进鱼口游动的唯一低流速上溯通道,鱼类聚集点趋于唯一,验证了导鱼堰方案的合理性。利用鱼类洄游模型对导鱼堰的导鱼效果进行预测,结果表明,下游高水位和低水位2种工况下,90%以上的鱼类游动路径均表现出相似的规律,鱼类沿河道右岸和导鱼堰下游侧的低流速通道上溯,并最终聚集在集鱼渠的进鱼口处。放鱼试验中试验个体全部进入集鱼渠,结果进一步证实导鱼堰可以有效引导鱼类游动路线,并在集鱼渠进鱼口处形成唯一的聚集区。本文提出的导鱼堰丰富了生态水工建筑物的形式,可为过鱼设施进口的水力设计及下游河道的局部整治提供参考。
文摘针对当前考虑弹药消耗多重影响因素所反映的规律不够客观,长时间弹药消耗没有考虑其消耗规律等问题,提出了利用长短期记忆神经网络(long short term memory,LSTM)来分析弹药消耗的规律。通过示例数据的训练集和测试集,来进行弹药消耗的预测。通过对比RNN模型和BP神经网络模型在测试集上的平均绝对误差(mean absolute error,MAE)和均根方差(root mean square error,RMSE),LSTM神经网络在MAE和RMSE上的误差小,对于长时间序列弹药消耗数据有着很好的预测效果。
基金supported by China Bureau of Geological Survey,the Department of Land and Resources of Guangxithe National Natural Science Foundation of China(grant#40862001)
文摘A new large-bodied theropod dinosaur, Datanglong guangxiensis gen. et sp. nov., was recovered from the Lower Cretaceous Xinlong Formation of the Datang Basin, Guangxi. It is unique in several features including： posteriormost dorsal vertebra with teardrop-shaped pneumatic foramen confined by enlarged pcdl, acpl and the centrum; posteriormost dorsal with well-developed, horizontal prpl; posteriormost dorsal with a parapophysis projecting more laterally than the diapophysis; brevis fossa shallow with short, ridge-like medial blade; and iliac pubic peduncle with posteroventrally expanded margin. Cladistic analysis supports the idea that this new taxon Datanglong guangxiensis is a primitive member of the Carcharodontosauria in possessing two unambiguous synapomorphies： large external pneumatic foramina and internal spaces present in the lateral surface of ilium, and a peg-and-socket ischiac articulation with the ilium. The presence of the new taxon from Guangxi further confirms that Carcharodontosauria were cosmopolitan large-bodied predators during the Early-mid Cretaceous.
