液压振动台试验系统中的控制系统集成设计

根据液压振动台试验系统的功能特点,采用Labview软件将液压振动台试验系统的主要控制部件的软、硬件开发和系统集成优化,大大降低了试验系统的人力成本,提高了工作效率,操作简单便捷。     

离子色谱法测定水中硫酸盐质量控制指标研究

运用离子色谱法对硫酸盐的标准样品和实际样品进行研究分析,通过全国多家实验室的大量监测数据,得出了当前常用的精密度及准确度方面质量控制指标的建议值。研究表明：在0．5～230mg／L浓度范围内,标准样品的RSD≤3．0％,RSD’≤7．0％,RE≤±15％。实际样品0．5～210mg／L。RD≤4．0％,加标回收率范围为90％-115％。     

Host intra-clutch variation,cuckoo egg matching and egg rejection by great reed warblers

Prevailing theory predicts that lower levels of intra-clutch variation in host eggs facilitate the detection of brood parasitism. We assessed egg matching using both human vision and UV-VIS spectrophotometry and then followed the nest fate of great reed warblers naturally parasitised by European cuckoos. Rejection was predicted by the following three variables: matching between cuckoo and host eggs on the main chromatic variable defined by principal components analysis of the egg spectra (which has a strong loading in the UV); the number of host eggs in the nest; and human estimates of intra-clutch variation. The first variable is not correlated to human estimates of matching, which do not predict rejection. In line with another recent study, rejection rates were predicted by higher levels of intra-clutch variation in the host eggs, suggesting that higher rather than lower levels of intra-clutch variation can facilitate the discrimination of cuckoo eggs by hosts. We suggest that the importance of intra-clutch variation is context dependent, with intra-clutch variation being important when there is good matching between the host and the cuckoo eggs. Our results also suggest that both spectrometric and human visual assessments of egg matching and intra-clutch variation are prudent: the former provide the best method of estimating reflectance variation, whereas the latter include some assessment of patterns of maculation.     

水培条件下油白菜对Pb、Cd吸收和转运的影响

采用水培实验和室内分析相结合的方法,研究了不同含量Pb、Cd单一和复合污染对金属Pb、Cd吸收和转运的影响。结果表明,Pb和Cd主要在油白菜的根部富集;Cd和Pb不同添加量与油白菜体内累积量之间呈显著正相关。复合污染处理中,油白菜地上部的转运系数BCFCd随外源Pb含量的增大而增加,而根部则相反,即BCFCd随外源Pb含量的增大而降低,说明外源Pb可以促进油白菜对Cd在叶片中的富集,但会抑制Cd在根中的富集;油白菜地上部的BCFPb随外源Cd含量的增大而降低,而根部则相反,即BCFPb随外源Cd含量的增大而增加,说明外源Cd可以促进油白菜对Pb在根中的富集,但会抑制Pb在叶片的富集,Cd对Pb的富集具有双重作用;高含量的Pb(≥500 mg/L)会促进油白菜根部的Cd向地上部转运,而高含量Cd会抑制油白菜根部的Pb向地上部转运,使得更多的Pb滞留在油白菜地下部。     

A laboratory technique for investigation of diffusion and transformation of volatile organic compounds in low permeability media

A laboratory diffusion cell technique that permits spatial and temporal estimates of porewater concentrations over short intervals suitable for estimation of effective diffusion coefficients (De) and degradation rate constants (k) of volatile organic compounds (VOCs) in saturated low permeability media is presented. The diffusion cell is a sealed cylinder containing vapour reservoirs for sampling, including a vapour reservoir source and an array of vapour-filled "mini-boreholes", which are maintained water- and sediment-free by slightly negative porewater pressures. The vapour reservoirs were sampled by Solid Phase Micro-Extraction (SPME), resulting in minimal disturbance to the experimental system. Porewater concentrations are estimated from the measured vapour concentrations. Experiments were conducted using a non-reactive medium and five VOCs with a range in partitioning properties. Calibration experiments showed that equilibrium partition coefficients could be used for calculating concentrations in the vapour reservoir source from concentrations in the SPME coating after a 1-min microextraction and that the reservoir concentration was insignificantly affected by sampling. However, equilibrium was not reached during the one-min extraction of the boreholes; the microextraction reduced the borehole vapour concentrations, leading to diffusion of VOCs from porewater into the vapour-filled borehole. Thus, empirical partitioning coefficients were required for the determination of porewater VOC concentrations. The experimental data and numerical modelling indicate masses extracted by SPME extraction are relatively small, with minimal perturbation on processes studied in diffusion experiments. This technique shows promise for laboratory investigation of diffusion and transformation processes in low permeability media.     

Bioaccumulation of toxicants in the zebra mussel, Dreissena polymorpha, at the Times Beach Confined Disposal Facility, Buffalo, New York

This study consisted of a site characterization followed by biomonitoring the zebra mussel, Dreissena polymorpha, at the Times Beach Confined Disposal Facility (CDF), located in Buffalo, New York. Concentrations of selected contaminants, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and metals -arsenic (As), chromium (Cr), barium (Ba), mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se) and silver (Ag)-were at or below detection limits in the water column. Sediment contaminant concentrations, recorded as dry weight, were as high as 549 mg/kg for total PAHs, 9 mg/kg for PCB Aroclor 1248 and 54, 99, 6, 355, 637 and 16 mg/kg for the metals As, Ba, Cd, Cr, Pb and Hg, respectively. To predict contaminant bioavailability, elutriate and whole sediment toxicity tests were performed utilizing the cladoceran, Daphnia magna. Whole sediment tests indicated significant impact. Control survival was 84%, while sediment treatment had survival ranging from 1 to 7%. Mean control reproduction was 86.8 neonates, whereas treatment reproduction ranged from 1.4 to 9.0. Zebra mussels placed both in the water column (Upper) and at the sediment level (Lower) survived the 34-day exposure. Contaminants that significantly accumulated in zebra mussel tissue (wet wt mg/kg) were total PAHs (6.58), fluoranthene (1.23), pyrene (1.08), chrysene (0.98), benzo(a)anthracene (0.60), PCB Aroclor 1248 (1.64), As (0.97), Cr (2.87) and Ba (7.00). Accumulation of these contaminants in zebra mussel tissue represent a potentially realistic hazard to organisms (i.e. fish and birds) that feed on them.     

Reduction in organic effluent static acute toxicity to fathead minnows by various aeration techniques

This study compared results of no aeration, intermittent aeration, and constant aeration strategies in determining the static acute (48-h) toxicity of phenolic-based effluents to adult fathead minnows (Pimephales promelas). Toxicity was greatest in no aeration tests followed by intermittent aeration and constant aeration. Two factors were considered responsible for the observed patterns of toxicity. First, in side-by-side tests of no versus intermittent aeration and intermittent versus constant aeration, toxicity reductions were directly attributed to maintenance of dissolved oxygen above 5.0 mg litre(-1) in aerated containers. Secondly, toxicity was reduced when treatment system temperatures were warmest, probably due to increased microbial activity and volatilisation during late spring to early autumn (temperatures > 16 degrees C). Effluent was slightly more toxic on- than off-site, presumably due to degradation of phenolic compounds during transport and set-up at the off-site laboratory (approximately 4.5 h). Gill tissue ultrastructure and histopathology were used to determine the extent of effluent-induced damage and the recovery of minnows to short (6-h) effluent exposures. After a 48-h exposure to the approximate LC(50) level, gill tissue lamellae were characteristically desquamated with epithelium lifting from the basement membrane. Gill tissue was similarly damaged after a 6-h exposure to 100% effluent and had recovered to pre-exposure conditions after 42 h in clean water. Aeration strategies in these studies demonstrated potential air-stripping of volatile compounds, although stress to test organisms from low dissolved oxygen was relieved.     

春季莱州湾南部溶解态营养盐研究

在1997年5月、1998年6月两次对莱州湾南部调查的基础上，讨论了该海区溶解态营养盐的时空分布规律和来源。认为PO4^3-－P、NH4^ －N、NO2^-主要来源于南部沿岸及河口，NO3^-主要受北部黄河的影响，SiO3^2-同时受黄河及南部河口的影响，黄河对该海区有重要影响。小清河已对部分海区造成污染。     

渤海莱州湾沉积物-海水界面磷酸盐的交换通量

于 1 997年 5月和 1 997年 7月利用现场培养的方法对莱州湾沉积物 海水界面的交换行为进行了研究 .渤海莱州湾磷酸盐的交换通量为 6 7— 6 8μmol·m- 2 ·d- 1 .培养结果表明 ,富氧或贫氧环境对磷的交换通量没有显著影响 ;生物活动对磷的交换通量影响显著 ;与世界其它海区相比较 ,渤海莱州湾磷酸盐的交换通量处于中等水平