松花江哈尔滨段主干流常规污染物动态衰减速度系数的测算研究

采用2011—2013年松花江哈尔滨段各断面水质监测数据和老头湾水文数据,运用实测资料反推法和河流一维水质模型对该段干流的COD、BOD5、NH3-N的衰减速度系数K进行测算,结果表明:1—12月朱顺屯—大顶子山的KCOD、KBOD5、KNH3-N分别在0.035 d-1~3.372 d-1、0.368 d-1~5.459 d-1和0.245 d-1~5.600 d-1之间;冰封期各污染物K值小于明水期,夏季(6—8月)K值大于其他季节。以2013年阿什河口下—呼兰河口下河段上、下游各断面的监测数据对测算的各污染物动态K值进行率定,实际监测值与预测浓度年内变化趋势基本一致,相对误差在25%以内,水质验证结果较满意。     

大体积进样技术结合同位素稀释法测定地表水中多环芳烃的研究

采用C18固相萃取柱预处理水样,由于固相萃取柱的选择吸附性,净化了样品的基质;同液-液萃取相比,固相萃取柱和硅胶小柱的双重净化,更适合大体积进样。萘、苊、菲、屈艹的氘代化合物作为同位素稀释剂,由于待测分析物与同位素稀释剂物理化学的相似性,其在固相萃取柱的保留行为和色谱运行行为都有基本一致性。同一般内标法相比,同位素稀释法具有较高的回收率。大体积进样由于进样绝对量的增加,降低了检出限。方法检出限0.05～0.1ng/L,回收率范围90%～110%。     

Sperm allocation in an uncertain world

Models of optimal sperm allocation are constructed using stochastic dynamic programming techniques, yielding predictions about sperm allocation when males mate sequentially, breeding time is finite, sperm stores are limited and females vary in quality. The models suggest that uncertainty of future reproductive opportunities should favour withholding of sperm, so that males tend to allocate less (for a given level of stored sperm) earlier in the breeding season. This effect is more pronounced the greater the variance in female quality. We also show that while allocation will be influenced by mate value, it is not necessarily optimal to allocate preferentially to high-quality females, since the benefits of a higher-quality mate may be offset by increased risk of rejection of sperm or higher sperm competition. The relationship between mate quality and level of allocation will depend strongly on the amount of remaining stored sperm, with males whose supplies are depleted being more likely to favour lower-quality partners. Received: 12 September 1997 / Accepted after revision: 28 June 1998     

Seaward coastal defence: limitations and possibilities

In The Netherlands shoreline retreat is actively counteracted, mostly by means of beach nourishment in which some allowance is made for natural fluctuations. For some parts of the coast, however, a more active socalled ‘seaward coastal defence strategy’ might be more profitable. This applies to coasts with a small dune ridge subject to severe erosion. According to this strategy the morphological system is influenced in such a way that erosion is prevented, which will result in a stable or even an accretion coastline. The effectiveness of the seaward coastal defence strategy has to be compared with maintenance by beach nourishment. The effects on the morphological system, the environment and other interests must also be analysed. Several seaward solutions are possible. In order to gain more insight into the behaviour of these solutions, comparative pilot studies have been executed for the most vulnerable locations. This paper gives an overview of the main conclusions of the pilot studies in comparison with sand nourishment, the main coastal defence measure.     

染整废水氧转移系数Kla值的研究

研究了染整废水中氧转移的速率,为工程设计、曝气机选择及动力效率测定,提供了科学理论依据。     

Model-based direct search optimization of the broke recirculation system in a newsprint mill

This work is concerned with the dynamic modelling of the papermaking section of an integrated newsprint mill, and the subsequent application of two direct search methods in a proof-of-concept optimization study of broke recirculation strategies. The effect of the current broke recirculation policy on the mixed pulp properties at the paper machine headboxes was quantified using a dynamic simulation generating data for an objective function which reflected the rate of change in measurable (flow, consistency and temperature) and immeasurable (total dissolved solids and fibre length distribution) parameters. Genetic Algorithm and the Nelder–Mead simplex methods were then linked dynamically to the simulation and used to find improved ways of recirculating broke pulp. Specifically, the profile of the changes to the broke ratio was modelled using a quadratic function and a second-order transfer function, and the coefficients of these functions were optimized. The optimized broke recirculation resulted in a significant reduction in the value of the objective function, thus, suggesting that the fluctuations in the properties of the mixed pulp stream could be dampened and paper machine headbox stability improved. It is expected that this process enhancement strategy would contribute to an increase in production yield (via a reduction in the occurrence of paper machine breaks), and thus an overall reduction in the waste of materials and energy.     

我国矿产资源开采中的损失贫化浅析

矿产资源开采中的损失与贫化问题直接关系到国家矿产资源的综合利用程度和可持续发展的问题。我国矿产资源开采中损失贫化大的问题 ,加速了资源枯竭的速度 ,缩短了矿井服务年限 ,加剧了矿产资源供求矛盾 ,造成金属大量流失、开采成本提高、经济效益差并严重阻碍了矿山的发展。文章分析了我国矿产资源开采中的损失贫化大的根源 ,并提出了解决矿石损失贫化的有效途径和低贫损开采模式。     

嘉兴市污水海洋处置工程近区稀释度变化研究

针对嘉兴市污水海洋处置工程拟选的场前 0 0 0 0和场前 0 14 0 0两个排放口 ,对一个潮位过程中污水近区初始稀释度的变化进行了物理模型试验研究 ,以国家二类海水水质标准 (GB 30 97 82 )作为控制依据 ,根据稀释度变化过程线计算出了 2 4h内可以满足二类海水水质标准的时间。试验结果表明 ,场前 0 14 0 0排放口处的近区稀释扩散效果最好。     

修正SO2被动式采样器的感度

二氧化硫被动式采样器的采样感度受环境中湿度和硫酸盐等的影响，感度经修正后用于环境监测，其结果与紫外荧光法的相对误差小于１０％。     

大亚湾冬春季微型浮游动物摄食研究

2004年12月和2005年3月份分别在大亚湾5个典型站位采样,用现场稀释法研究了冬春季大亚湾微型浮游动物对浮游植物的摄食率(g)和浮游植物的生长率(μ)。结果显示:12和3月份大亚湾浮游植物的生长率分别为0．18-1．19 d-1,0．16-1．14 d-1,微型浮游动物的摄食率分别为1．00-2．08 d-1,0．33-1,74 d-1,微型浮游动物对浮游植物现存量的摄食压力范围为76％-287％,47％-258％,对潜在初级生产力的摄食压力范围分别为101％-445％,70％-330％。说明大亚湾作为典型的亚热带海湾,具有高的μ、g值,微型浮游动物对浮游植物的摄食压力也处于较高水平。