叶轮出口边对双蜗壳泵压力脉动的影响

泵的叶轮扫掠蜗壳隔舌时产生的压力脉动是引起船用泵振动噪声的原因之一.为尽可能弱化这一影响,分别设计了叶片出口边与前后盖板基本面垂直和倾斜的2种不同形式叶轮,将其配置在相同的双蜗壳中,通过数值计算与样机试验相结合的手段,对蜗壳内9个不同位置的压力脉动情况进行对比分析.结果表明:出口边倾斜的叶轮相比于出口边垂直的叶轮可明显改善蜗壳内次脉动的“驼峰”现象,且可以进一步降低隔舌处主波动的压力峰值;对蜗壳内2个隔舌稍前的位置,出口边倾斜的叶轮反而会使得该点的压力系数幅值明显增大,且该点主波动的周期数发生改变;2种叶轮出口边的不同形式对蜗壳出口位置的压力脉动的影响基本相同;采用出口边倾斜叶轮对改善因叶轮与隔舌间的液流压力脉动是可行的.     

野生金头闭壳龟的资源现状调查

笔者于2001-2004年对金头闭壳龟(Cuoraaurocapitata)的野生种群的分布、数量及相关生态学进行了专项调查。结果表明,金头闭壳龟目前仅分布于青弋江源头和上游即北纬30°-30°52′的少数支流中,具体为安徽省泾县的古坝、蔡村和孤峰三地的山涧溪流以及黟县红星乡的清溪河流域。野外种群数量十分稀少,目前已不足400只。金头闭壳龟主要栖息在水质清澈、两侧植被茂密或一侧山脚多石缝的山涧溪流中。经对曾经发现过金头闭壳龟典型地带的各种生态指标的测量表明,泾县古坝乡沈村上沈村段的古坝河段的以及蔡村乡的东园至爱民段的丁溪河段,相比而言仍不失为金头闭壳龟较为理想的栖息地。     

Investigation of Interspecies Interactions within Marine Micromonosporaceae Using an Improved Co-Culture Approach

With respect to bacterial natural products, a significant outcome of the genomic era was that the biosynthetic potential in many microorganisms surpassed the number of compounds isolated under standard laboratory growth conditions, particularly among certain members in the phylum Actinobacteria. Our group, as well as others, investigated interspecies interactions, via co-culture, as a technique to coax bacteria to produce novel natural products. While co-culture provides new opportunities, challenges exist and questions surrounding these methods remain unanswered. In marine bacteria, for example, how prevalent are interspecies interactions and how commonly do interactions result in novel natural products? In an attempt to begin to answer basic questions surrounding co-culture of marine microorganisms, we have tested both antibiotic activity-based and LC/MS-based methods to evaluate Micromonosporaceae secondary metabolite production in co-culture. Overall, our investigation of 65 Micromonosporaceae led to the identification of 12 Micromonosporaceae across three genera that produced unique metabolites in co-culture. Our results suggest that interspecies interactions were prevalent between marine Micromonosporaceae and marine mycolic acid-containing bacteria. Furthermore, our approach highlights a sensitive and rapid method for investigating interspecies interactions in search of novel antibiotics, secondary metabolites, and genes.     

Structural and Molecular Characterization of Squalene Synthase Belonging to the Marine Thraustochytrid Species Aurantiochytrium limacinum Using Bioinformatics Approach

The marine microorganisms thraustochytrids have been explored for their potential in the production of various bioactive compounds, such as DHA, carotenoids, and squalene. Squalene is a secondary metabolite of the triterpenoid class and is known for its importance in various industrial applications. The bioinformatic analysis for squalene synthase (SQS) gene (the first key enzyme in the tri-terpenoid synthesis pathway), that is prevailing among thraustochytrids, is poorly investigated. In-silico studies combining sequence alignments and bioinformatic tools helped in the preliminary characterization of squalene synthases found in Aurantiochytrium limacinum. The sequence contained highly conserved regions for SQS found among different species indicated the enzyme had all the regions for its functionality. The signal peptide sequence and transmembrane regions were absent, indicating an important aspect of the subcellular localization. Secondary and 3-D models generated using appropriate templates demonstrated the similarities with SQS of the other species. The 3-D model also provided important insights into possible active, binding, phosphorylation, and glycosylation sites.     

基于Web的海洋计量检测实验室管理信息系统设计

介绍基于Web的海洋计量检测实验室管理信息系统的规划、分析与设计,采取了Browser／Web Server、JSP、JDBC和Jasper Reports等技术开发了本系统。阐述了本管理信息系统的体系结构、子系统划分,以及相关技术、安全策略、实施和运行机制,着重讨论系统需求、系统解决方案及数据库设计和程序设计的要点。     

温室甲鱼养殖生石灰的合理使用

生石灰是水产养殖的一种常规药物,非常普遍的用在水质消毒,疾病防治中,许多水产养殖用户也把生石灰作为一种常用的水质改良剂,但在甲鱼的养殖中,要根据情况酌情使用,否则,会出现pH值过高从而导致有毒气体的产生,造成甲鱼中毒的病况。本文介绍了温室甲鱼养殖中生石灰使用不当引起的病况,并提出了相应解救措施。实验中采用了生石灰日常消毒常用的浓度和间隔日期,伴随着pH值与氨氮的浓度升高,甲鱼出现了死亡现象,在解除了生石灰的使用后,甲鱼停止了死亡现象。     

共附生海洋微生物抗菌活性物质的研究

随着抗生素的广泛使用,微生物的抗药性逐渐增强.与此同时,环境污染的加剧,社会和人文的变迁,使人类的免疫力不断下降,新的致病菌和条件致病菌不断出现,这些已经成为严重的社会问题.解决问题的最有效办法就是加大力度,筛选开发新的抗生素.海洋拥有独特的生境条件,已成为新抗生素的重要来源.海洋微生物中共附生微生物具有独特的特点,已逐渐成为研究的焦点.     

内导叶滚筒式收鱼机设计与实验

针对深海域网箱养殖人工收鱼效率低、且劳动强度大,吸鱼泵等传统收鱼装置鱼损率高、需要装备大功率发电系统、不适合中小型收鱼船作业等问题设计了内导叶滚筒式收鱼机。对该装置的主体结构进行仿真,确定了主体结构发生最大等效应力和应力集中的位置,根据仿真结果进一步优化结构,并试制了实验装置。通过实验得出最优控制方案,即在倾角10°、转速15.3r/min情况下,有效输送量与功耗比最优,且滚筒在不同倾角下最优转速为15r/min,实验鱼损率为0.1%,满足用户要求。该装置能在保证一定收鱼效率的同时降低鱼损率,适合中小型渔船收鱼作业。