发酵罐高密度培养盘基网柄菌

利用SIH合成培养基,在7 L发酵罐培养盘基网柄菌.培养147 h后,细胞密度达到4.0×107mL-1,为在复杂培养基上所能达到的细胞密度的2~4倍.培养过程中葡萄糖的消耗量为6.7 g/L,产氨浓度达0.88 g/L.对培养基中的氨基酸分析表明,赖氨酸、色氨酸、甲硫氨酸和苯丙氨酸消耗较快,显示SIH培养基的氨基酸成分还可进一步优化.采用基于Monod生长动力学的半经验模型可很好模拟细胞生长和底物消耗,并估计出动力学参数μm ax=0.115 h-1,Nm ax=6.0×107mL-1.本研究为进一步优化合成培养基和为利用这一新型真核表达系统大规模生产重组异源蛋白奠定了基础

基于ALIF-PE-GOLSSVM的齿轮箱故障诊断

提出了基于基因优化最小二乘支持向量机（Gene optimized least squares support vector machine，GOLSSVM）的自适应局部迭代滤波（Adaptive local iterative fittering，ALIF）和排列熵（Permutation entropy，PE）的故障诊断方法，并将该方法应用于齿轮箱的诊断，成功实现了对齿轮箱4种故障种类的识别。针对排列熵无法直接识别齿轮箱不同故障类别的问题，利用ALIF方法相较于EMD方法在去除残余噪声及抑制模式混叠上的优势，使用ALIF方法对故障信号进行降噪，提取有效分量，再计算有分量的PE值（C-PE值），以获得振动信号的多尺度特性；然后，使用基因算法对最小二乘支持向量机（Least squares support vector machine，LSSVM）进行了优化；最后，将特征向量输入到GOLSSVM，对故障特征进行分类。结果表明，所提方法相比BP神经网络和SVM在故障识别精度上有优势

Preliminary study on distribution of micro-protozoa in the Pearl River Estuary and its controlling factors

分析了2004年2月珠江口小型原生动物(包括鞭毛虫、纤毛虫和异养甲藻)的分布特征,探讨了环境因子对其分布的影响。结果表明,鞭毛虫在珠江口的丰度为3.4x103~25.6x103个/Ml,异养甲藻的丰度为11~312个/Ml,纤毛虫的丰度为7~172个/Ml。高丰度的原生动物主要集中在广州附近盐度为2~5的河口上段,而低丰度在外海盐度超过30的下段区域,原生动物的3个类群的丰度均从上段往下段呈递减的趋势。原生动物的分布特征与浮游植物叶绿素A的分布特征相似,原生动物也与细菌呈显著的正相关,表明细菌和浮游植物影响着原生动物在珠江口内的分布。冬季温度对原生动物的分布不具有直接的影响作用,而营养盐可能是通过影响浮游植物及细菌的分布而间接对原生动物的分布产生影响。原生动物的丰度表明珠江口部分水域已处于富营养化和超营养化状态。Based on the data obtained from a cruise in Feb.2004,abundance,spatial distributions and controlling factors of nanoflagellates,heterotrophic dinoflagellates and ciliates in the surface layer in the Pearl River estuary were studied.Nanoflagellates abundance ranged from 3.4×103 to 25.6×103 cells/mL,while heterotrophic dinoflagellates ranged from 11 to 312 cells/mL and ciliates were from 7 to 172 cells/mL,respectively.High abundance of these protozoa was observed at upper stream of the estuary near the Guangzhou waters with low salinity(2 to 5 psu).Low abundance was observed at lower stream of the estuary with high salinity(>30 psu).The three groups of protozoa abundance decreased from upper estuary near Guangzhou to lower estuary.The distribution patterns of these protozoa abundance were similar to that of chlorophyll a,and they had a significant relationship with bacteria,indicating that phytoplankton and bacteria influence protozoa distribution patterns.Temperature and nutrients were not direct factors influencing protozoa distribution.High abundance of protozoa suggested that the Pearl River Estuary was eutrophic water.国家自然科学基金项目(40730846;90711006