不同干露条件单环刺螠的耐受性及对体表黏液特性的影响

为了研究单环刺螠Urechis unicinctus在不同温度(15、20、25、30℃)的湿沙无水和湿沙有水干露条件下的耐受性、体表黏液分泌量及成分含量的变化,试验采用离心管提取平均体质量为2.75 g的单环刺螠体表黏液,采用苯酚-硫酸法和总蛋白测定试剂盒分别检测黏液中多糖和蛋白质含量,同时研究其黏液对金黄色葡萄球菌Staphylococcus aureus、灿烂弧菌Vibrio splendidus、奇艺变形杆菌Bacillus mirabilis、产气肠杆菌Enterobacter aerogenes、阴沟肠杆菌Aerobacter cloacae、哈维氏弧菌Vibrio harveyi、副溶血弧菌Vibrio parahaemolyticus、鳗弧菌Vibrio anguillarum、藤黄微球菌Micrococcus luteus等常见水产动物病原菌的抗菌性,采用抑菌圈法通过比较抑菌圈直径以判断抗菌效果。结果表明:单环刺螠体表黏液分泌量随温度升高而降低,湿沙无水干露条件下的单环刺螠耐受性要强于湿沙有水;15℃条件下,10只单环刺螠湿沙无水和湿沙有水型分别在1 min(3.33 mL±0.05 mL)和10 min(2.85 mL±0.04 mL)时黏液分泌量较高;湿沙无水条件下多糖(1.04μg/mL±0.10μg/mL)及蛋白质(65.81 mg/mL±2.22 mg/mL)含量均在30 min时最高,且随干露时间的延长均呈先升高后降低的趋势;体表黏液对所测9种病原菌的抑菌圈直径小于10 mm,均无抗菌性。研究表明,2.75 g规格的单环刺螠,在15℃湿沙无水干露条件下耐受性可达48 h以上。

预应力土层锚杆加固前倾闸室墙优化设计

为解决重力式闸室墙前倾问题,以某船闸工程为例,对多个加固方案进行技术经济比较,并采用三维有限元法,对推荐方案的设计参数影响规律进行研究。结果表明:预应力土层锚杆加固方案造价经济,对周边环境影响小,其锚索张拉力对重力式闸室结构影响的敏感性较小,张拉高程在约23墙高处墙身应力较小,当锚索间距较大时,锚索间土体会出现一定的拉应力。合理设计预应力土层锚杆参数,可有效控制墙身及土体应力,取得良好的加固效果。该方法不仅可应用于船闸大修工程,也可为水闸、箱涵等其他类似水工结构的加固改造提供参考。

Distribution of Heavy Metals in the Sediments in Polluted Coastal Regions of China and Their Ecological Risks

[ Objective] The aim was to study the distribution and its ecological risks of heavy metal in the sediments of the polluted coastal regions in Bohai Bay, Changjiang and Zhujiang estuaries. [Method] The economic activities had great influence on the Bohai Bay, Changjiang and Zhu- jiang estuaries. The pollution of different heavy metals in the deep ocean was summarized by summary of the relation between the distribution of heavy metals and economic activities. [ Result] In general, influenced by economic development, the heavy metal pollution in coastal area in China was pessimistic. The sediments in the Bohai Bay, Changjiang and Zhujiang estuaries showed different degrees of Cd, Cr, Zn, Cu and Pb pollution. As pollution in Bohal Bay and Zhujiang estuaries can not be neglected. The heavy metal pollution may pass into human body with the transportation of food chain. [ Conclusionl The study provided reference for the formulation of policies to restrain heavy metal emission and protection of human health.