Organochlorine and Mercury Residues in Young-of-the-Year Spottail Shiners from the Detroit River,Lake St. Clair,and Lake Erie

Young-of-the-year spottail shiners (Notropis hudsonius) were used as biomonitors to determine the spatial distribution (1982/83) and assess trend data for organochlorine and mercury residues. Significantly (p < 0.01) higher PCB residues were found in Detroit River spottail shiners than in collections from southwestern Lake St. Clair and northwestern Lake Erie. The highest PCB residues were found in the west bank collections from Michigan waters (912–2,997ng/g) compared to the mid-stream (96–290 ng/g) and east bank collections (153–316 ng/g). Chlordane residues were found to be elevated in all spottail shiner samples from urbanized areas. Octachlorostyrene and ∑ DDT residues were distributed uniformly within the study area, whereas mercury concentrations were found to be lower in spottail shiners from northwestern Lake Erie than in comparable samples from the Detroit River and southwestern Lake St. Clair. Residues for BHC, heptachlor, aldrin, and chlorinated benzenes were near their detection limits; mirex and chlorinated phenols were not detectable. Recent (1982/83) PCB residue levels in spottail shiners exceeded the IJC aquatic life objective (Great Lakes Water Quality Agreement of 1978) at all the sites sampled, except at Pike Creek in Lake St. Clair. PCB residues in spottail shiners from Pike Creek, Big Creek, and Leamington have declined significantly (p < 0.01) since the mid-seventies. Mercury and chlordane residues have decreased in spottail shiner samples from Leamington, but have remained virtually unchanged at Big Creek and Pike Creek.     

Butyltin Species and Inorganic Tin in Water and Sediment of the Detroit and St. Clair Rivers

Water and sediment samples from 29 locations in the Detroit and St. Clair rivers were analyzed for the highly toxic tri-n-butyltin (Bu₃Sn⁺) species and for the less toxic di-n-butyltin (Bu₂Sn²⁺) and n-butyltin (BuSn³⁺) species and inorganic tin. In general, locations sampled in the St. Clair River were less contaminated with butyltin species than those in the Detroit River. Inorganic tin and BuSn³⁺ were detected in over 90% of all subsurface water samples, while Bu₂Sn²⁺ and Bu₃Sn⁺ were detected in 45 and 28% of the same samples, respectively. The highest concentration ofBu₃Sn⁺ in subsurface water, 5.9 × 10^?10 mol Sn/L, was at the mouth of the Ecorse River, a tributary of the Detroit River. The three butyltin species and inorganic tin were also detected in 23–46% of all sediment samples. The highest concentrations of Bu₃Sn⁺ in sediment were found close to the mouths of the River Rouge, another tributary of the Detroit River, and the Ecorse River, and were 6.2 × I0^–7 and 1.7 × I0^–7 mol Sn/kg dry weight, respectively, for the top 2 cm of sediment.     

Preliminary Assessment of Contaminants in Soft Sediments of the Detroit River

Soft sediments from the Detroit River were analyzed for the USEPA priority pollutants to generally characterize contaminant distribution. Forty-three were detected. Highest heavy metal concentrations were found in the Trenton Channel and immediately downstream of Grosse Ile. They ranged from an area mean (N = 2) of 0.19 mg/kg mercury to 338.7 mg/kg zinc (dry weight). Polynuclear aromatic hydrocarbons ranged from 0.1 mg/kg to 38.8 mg/kg (mean, N = 2) with the highest levels near Grosse Ile. PCBs ranged from 0.015 mg/kg to 1.7 mg/kg (mean, N = 2). Organochlorine pesticides were not detected except for a trace of heptachlor in one sample. Sediment contamination in the Detroit River is widespread with higher concentrations on the U.S. side downstream of the Rouge River and in the Trenton Channel. The significance of these in-place pollutants to biota and as a source to Lake Erie is still unknown.     

基于高能效及公平性的移动设备定位算法

通过分析校园师生基于GPS的真实活动轨迹,以及何种算法才最适合具有自私性的移动用户展开合作,提出一种高能效及用户公平定位技术.通过采用代理设备合作思想,提出一种集中式最优算法,在保证固定精度界限和设备公平的基础上,实现移动设备GPS时间平均功率最小化.通过控制退避时间和GPS关闭时间,提出一种分布式准最优算法.最后,基于多种拓扑结构进行全面的仿真实验,验证了算法的高能效性和公平性.     

石墨炉原子吸收测定化探样品中痕量金的研究

采用以王水分解样品,泡沫塑料富集,硫脲解脱,石墨炉原子吸收分光光度计测定微量金。研究了测定时干燥温度和时间的选择,原子化温度和时间的选择,灰化温度和时间的选择,以及王水体积分数对吸附效果等条件对测定结果的影响。该方法检出限为0.2×10-9,经国家一级分析标准样品验证,结果与标准值相符。     

选择溶解条件--ICP-AES法测定铝合金中10元素

在铝合金中,对常量、微量、痕量元素等的测量,传统上采用化学的方法来分析,手续繁杂,分析时间 亦长,有时不能满足大批量快速分析的要求。ICP-AES分析法,以其优异的分析性能被广泛应用于各种材料 的主要、次要,痕量、超痕量多元素的同时分析。但是,影响等离子炬状态的因素很多,只有在最佳工作状态下 操作,才能充分发挥ICP光源的优越性。     

Content of various elements in different parts of the tea plant and in infusions of black tea from Southern India

Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g⁻¹ tea) followed by P (700–1200 μg g⁻¹), Mg (300–700 μg g⁻¹), Ca and A1 (each 150–300 μg⁻¹), Mn (60–150 μg g⁻¹), Cu, Na, Si and Z n (each 6–50 μg g⁻¹), B, Ba, Cr, Fe, Ni and Pb (each Id μg g⁻¹), and Sr, Co and Gd (each <1μg g⁻¹). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.     

用油气运移痕迹的统计结果确定仓储层厚度--以东营凹陷为例

在对东营凹陷网毯式油气成藏体系结构进行研究的基础上，针对其中、东部的特殊地质情况，对仓储层进行了精细划分。以钻井油气显示和试油数据为依据，研究了仓储层中的油气运移规律，提出了仓储层厚度的界定方法，并指出厚度是影响仓储质量的关键因素，只有在构成仓储层的砂砾岩体达到一定厚度时才能成为有效仓储层。仓储层厚度越大的地方，越有利于油气的运移和聚集成藏。同时在仓储层中显示油气成藏和有油气运移痕迹所要求的砂砾岩体厚度是相近的，而与无油气运移痕迹的砂砾岩体厚度有明显的差别。并且随着埋藏深度的增加，要求作为仓储层的砂砾岩体厚度也随之增大。因此，可以通过计算仓储层厚度来评价仓储层的质量。该方法在实际应用中简便可行，对于评价类似地区的网毯式油气成藏体系仓储层的仓储质量有借鉴作用。     

Performance Monitoring and Assessment of Embedded HW/SW Systems

Performance assessment of embedded HW/SW systems built with various types of VLSI components, i.e. heterogeneous multi-processor architectures, is important to help the development of complex real-time applications. To design such a tool, two issues must be solved: the gathering of relevant information simultaneously on several components without disturbing the application behavior, display of the performance results in a way that can be easily interpreted by designers. This paper presents a significant solution for the two above issues. We first describe what the goal for designers is and what kind of applications are concerned. Then we describe the principle of collecting an event trace and the technique to evaluate the selected performance indexes. The monitoring technique, based on a specific ASIC, is non-intrusive and allows our tool to capture real-time event occurrences from software tasks, and even from hardware functions implemented in ASICs. Each event is automatically time-stamped, collected and processed in real-time to evaluate the performance indexes selected by the designer. We also describe the display tool which clearly shows the results to the designer according to different representations. This technique and the associate real-time performance analyzer are integrated in a complete development process based on the MCSE methodology.