一种高稳定船用电源系统的设计与实现

实际维修表明,船用雷达故障大多数是由供电造成。稳定的电源是保证雷达、罗经等设备安全运行的关键,而常用电源开关电源设计缺陷无法保证雷达的正常工作,由此设计一种由主机、辅机、应急电源换电过程中进行相互补偿式供电的雷达电源系统,确保在船电无法稳定供电的极限情况下,雷达等大功率设备依然正常工作。实践证明,该电源工作稳定可靠、输出精度高、体积轻巧、故障率低、效率高、维护方便,能够延长雷达重要部件的使用寿命,尤其满足工作环境恶劣的渔船通导设备工作需要。

七通道中空纤维超滤膜的制备与性能调控

以聚醚酰亚胺(PEI)为膜材料、N,N-二甲基乙酰胺为溶剂、水为凝固浴,采用干-湿相转化法制备七通道中空纤维超滤膜,研究了PEI含量和3种添加剂γ-丁内酯、聚乙二醇600(PEG600)、聚乙烯吡咯烷酮-K30对膜结构和性能的影响。结果表明,随着PEI含量升高,膜断面由指状孔向海绵状孔转化,拉断力和爆破压力大幅提升。以PEG600为添加剂时膜具有最佳的综合性能,拉断力为16.55 N,纯水通量为247.39 L/(m^2·h),对牛血清白蛋白的截留率达93.9%。

Morphologies of Eumelanins from the Ink of Six Cephalopods Species Measured by Atomic Force Microscopy

The morphologies of eumelanin, isolated from the six cephalopods species Sepia esculenta, Sepia lycidas, Sepia pharaonis, Sepiella japonica, Euprymna berryi, and Uroteuthis(Photololigo) edulis, were investigated using atomic force microscopy(AFM). The results showed that the hierarchical aggregate structures of irregular spherical particles with different diameters are the common characteristics of these eumelanins. Furthermore, the diameters of these spherical particles present an uneven distribution in a wide range and mainly concentrate in the range of about 20-150 nm. In addition, the eumelanin from different cephalopods species show obvious differences in the morphologies, which is illustrated by different assembly forms of diverse aggregate units and the quantitative features of eumelanin particles derived from the images.

广西隆安县是否为原始稻作农业发祥地探讨

本文从野生稻、大石铲、稻神山、民族民俗文化、石器时代考古材料等方面进行分析,对学者提出广西南宁隆安县是稻作原始农业发祥地的观点进行探讨,认为隆安县现有的论据不足,缺乏直接且关键性的证据,无法支撑该论点的提出。