Larval metamorphosis and morphological characteristic analysis of triploid shrimp Fenneropenaeus chinensis (Osbeck, 1765)

Both MI and MII triploids were successfully produced by heat shock in Chinese shrimp Fenneropenaeus chinensis. The inducing conditions for MI and MII triploids were optimized. The highest inducing rate obtained for MI triploids reached more than 90%, and that for MII triploids reached nearly 100% at the nauplius stage as evaluated using flow cytometry. Comparisons of survival rates at larval stages between triploids and diploids or diploids experiencing treatment and diploids without treatment were performed. At larval stage from nauplii to postlarvae, heat shocks lowered survival at larval stages even if the ploidy was not changed. Ploidy did not affect shrimp larvae survival, and no significant difference was found in the survival of shrimp larvae between MI and MII triploids. Highly significant differences were observed in the morphology of triploids and diploids, and no apparent difference was found in the morphology of MI and MII triploids at the grow-out stages. Discriminating formulae for triploid and diploid shrimp at grow-out stage were developed and could be used to distinguish triploids from diploids based on morphological parameters. MI and MII triploids of shrimp have the potential to be used in aquaculture.

机械密封在水下机器人中的应用

本文介绍在水下机器人中如何应用机械密封,其动、静环材料的选择,结构特点以及机械密封应用实例和经济效益.

井约束外推反演可信度与井震相关性关系研究

With the deepening development of oil-gas exploration and the sharp rise in costs, modern seismic techniques had been progressed rapidly. The Seismic Inversion Technique extracts seismic attribute from the seismic reflection data, inverses the underground distribution of wave impedance or speed, estimates reservoir parameters, makes some reservoir prediction and oil reservoir description as a key technology of Seismic exploration, which provides a reliable basic material for oil-gas exploration. Well-driven SI is essentially an seismic-logging joint inversion. The low, high-frequency information comes from the logging information, while the structural characteristics and medium frequency band depend on the seismic data. Inversion results mainly depend on the quality of raw data, the rationality of the process, the relativity of synthetic and seismic data, etc. This paper mainly research on how the log-to-seismic correlation have affected the well-driven seismic inversion precision. Synthetic, the comparison between middle –frequency borehole impedance and relative seismic impedance and well-attribute crossplots have been taken into account the log-to-seismic correlation. The results verify that the better log-to-seismic correlation, the more reliable the seismic inversion result, through the analysis of three real working area (Qikou Sag, Qiongdongnan basin, Sulige gas field).

金矿尾矿渣及其污染土壤中氰化物的分布及自然降解

某金矿1995年发生尾矿坝垮坝事件，富含氰化物的尾矿渣对农田和河流造成严重污染。事故3年、4年后，分别对废弃尾矿坝内和被污染农田内的土壤和沉积物中氰化物的水平和垂直剖面上的分布进行了采样分析。结果表明，氰化物在土壤剖面中自然降解速度大大慢于在天然水体中的降解速度；土壤剖面中氰化物的运移行为类似于土壤中易溶盐的迁移行为。在干旱、半干旱气候条件下，剖面中的氰化物可在土壤表面盐壳中高度富集，即使在4年后其浓度仍可高于新鲜尾矿浆中氰化物的浓度。土壤剖面中的粘质层可部分阻隔氰化物向潜水中运移，其结果又可导致粘质层中氰化物的高度富集。根据土壤中氰化物的自然降解特点，对垮坝引起的土壤污染给出了相应的防治措施。