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531.
固相萃取结合GC和GC—MS快速测定血浆中局麻药   总被引:6,自引:0,他引:6  
邱丰和  刘力 《环境化学》1995,14(3):246-250
本文用本实验室发展起来的X-5大孔高分子树脂固相萃取预处理技术,结合毛细管气相色谱和GC-MS,建立了人血浆中12种局部麻醉药的筛选方法。该方法快速简便,其灵敏度和线性范围满足临床急性中毒分析的要求。  相似文献   
532.
概括了自然保护区与社区的统一性和矛盾 ,分析了自然保护区与社区协调发展存在的主要问题 ,提出了自然保护区与社区协调发展的途径与方法 ,总结了一些保护区与社区协调发展的有效模式 ,包括政区合署模式、协调机构模式、保护与扶贫相结合模式、经济上双赢模式和公众参与模式  相似文献   
533.
The air pollution is the one of the most important environmental problems in Erzurum, situated in the eastern of Turkey, during winter periods. The unfavorable climate as well as the city’s topography, and inappropriate urbanization cause serious air pollution problems. The air pollutant concentrations in a city have a close relationship with its meteorological parameters. In the present study, the relationship between daily average total suspended particulate (TSP) and sulphur dioxide (SO2) concentrations with meteorological factors, such as wind speed, temperature, relative humidity, pressure and precipitation, in 1995–2002 winter seasons was statistically analyzed using the stepwise multiple linear regression analysis. According to the results obtained through analysis, higher TSP and SO2 concentrations are strongly related to colder temperatures, lower wind speed, higher pressure system and weakly lower precipitation and higher relative humidity. The statistical models of SO2 and TSP including meteorological parameters gave R2 of 0.74 and 0.88, respectively. Furthermore, the correlation between the previous day’s SO2, TSP concentrations and actual concentrations of these pollutants on that day was investigated and found as 0.84 and 0.53, respectively. In order to develop this model, previous day’s SO2 and TSP concentrations were added to the equations. The new model for SO2 enhanced considerably (R2 = 0.92), but for TSP new model was not enhanced (R2 = 0.89).  相似文献   
534.
GOAL, SCOPE AND BACKGROUND: Orimulsion (stable emulsion of natural bitumen and water) is a new imported industrial fuel in Lithuania. No data on its toxicity to fish is freely available. The aim of this study was to investigate sensitivity of rainbow trout (Oncorhynchus mykiss) to acute and chronic toxicity of orimulsion and to estimate the Maximum Acceptable Toxicant Concentration (MATC) of orimulsion to fish. METHODS: Laboratory tests were conducted on rainbow trout in all stages of development (embryos, larvae, adults). Acute toxicity (96-hour duration) and long-term (28 or 60-day duration) tests evaluating the wide range spectrum of biological indices were performed under semi-static conditions. RESULTS AND DISCUSSION: Median lethal concentration (96-hour LC50) values and their 95% confidence intervals derived from the tests were: 0.1 (0.09-0.12) to embryos, 0.06 (0.05-0.07) to larvae and 2.22 (2.02-2.43) to adult fish, and 28-day LC50 to adult fish was found to be 0.26 (0.21-0.32) g/l of total orimulsion respectively. The acute toxicity of orimulsion to rainbow trout can be characterised by a narrow zone of toxic effect and a sharp boundary between lethal and sublethal concentrations. The lowest 'safe' or 'no-effect' concentration values of total orimulsion obtained in long-term tests were equal to 0.09 g/l to adult fish, 0.019 g/l to embryos, and 0.0017 g/l to larvae. Proposed value of 'application factor' for orimulsion was found to be equal to 0.03. Since orimulsion has the property to disperse in all water volume, its toxic effect on fish can be characterised by the combined effects of dispersion and water-soluble-fraction. CONCLUSIONS: Maximum Acceptable Toxicant Concentration (MATC) of 0.0017 g/l of total orimulsion to fish was derived from long-term tests based on the most sensitive parameter of rainbow trout larvae (relative mass increase at the end of the test). According to substance toxicity classification accepted for Lithuanian inland waters, orimulsion can be referred to substances of 'moderate' toxicity to fish. RECOMMENDATIONS AND OUTLOOK: For prediction and evaluation of toxic impact of orimulsion accident spills on fish, some recommendations should be given. Since orimulsion has the property to disperse in all water volume during short time periods, the amounts of both spilled orimulsion and polluted water should be ascertained. Once both parameters are known, the real concentration of orimulsion in the water body must be determined. Then this concentration must be compared with 'safe' concentration to fish. By use of 'application factor' 0.03, approximate MATC for other fish species can be estimated when only acute toxicity data (96-hour LC50 value) is available.  相似文献   
535.
介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠  相似文献   
536.
Abstract

Urochloa decumbens plants may be reached by herbicide drift from applications of glyphosate from neighboring areas or by variations during applications. Considering the different phenological stages and size of plants in these areas, the amount of active ingredient that reaches the plants probably varies. The objective of this study was to evaluate the effects of the application of different doses of glyphosate on U. decumbens plants. Two greenhouse experiments were conducted with two replications at different times. The first experiment evaluated the biological response of U. decumbens plants to glyphosate doses (0, 2.81, 5.63, 11.25, 22.5, 45, 90, 180, 360, 720, and 1,440?g a.e. ha?1), with six replications. The second experiment evaluated the response of U. decumbens plants to the application of a selected low dose of 11.25?g a.e. ha?1. Evaluations of injury were performed at 0, 7, 14, and 21?days after application, and dry weight of plants was determined for each evaluation period. U. decumbens plants increased in dry weight when using the glyphosate dose of 11.25?g a.e. ha?1. However, plants had different responses to the application of this low dose. It can promote both stimulation and inhibition of plant growth.  相似文献   
537.
高炉煤气袋式除尘系统的问题及改进   总被引:1,自引:0,他引:1  
钢铁生产会产生大量的煤气.袋式除尘是高炉煤气除尘的发展方向.对重钢高炉煤气袋式除尘系统问题的分析研究结果表明:要使钢铁企业煤气除尘系统更高效、低耗、环保的运行,必须采用灵活、可操作性强的煤气温度调节手段,选择适宜的阀门和喷吹控制方式,优化除尘灰的保温模式和卸灰设备的结构等.  相似文献   
538.
炼油厂轻污染水回用试验研究   总被引:2,自引:0,他引:2  
针对某炼油厂轻污染废水水质情况,选用了BAF(生物曝气滤池)工艺+SF(砂滤)工艺对该废水进行净化处理。通过试验研究,得到了BAF工艺合适的运行参数,取得了满意的试验结果。经BAF工艺处理后,出水COD和油平均浓度分别为9.78mg/L和0.24mg/L,再经SF工艺进一步去除SS后,出水SS平均浓度为3.8mg/L,系统处理出水完全达到工业回用水水质要求。试验证明:BAF工艺是一种高效的处理方法,适合炼油厂轻污染水的净化处理。  相似文献   
539.
The purpose of this paper is to develop a set of associated statistical tests for spatial clustering. In particular, a set of three associated tests will be developed; these will correspond to the three types of tests set out by Besag and Newell (general tests, focused tests, and tests for the detection of clustering). The associated tests draw primarily, though not exclusively, upon existing tests and results. The principal contributions are based upon the score statistic for focused tests, which has been an important approach to testing for clustering around environmental hazards. The first contribution consists of the formulation of a global statistic for general tests that corresponds to focused score statistics, along with an assessment of the distribution of the statistic under the null hypothesis of no raised incidence. The local score statistics used for focused tests will have the property of summing to the global statistic used for the corresponding general test. Attention is also given to the maximum local score statistic for the “test for the detection of clustering”. The critical values of this statistic which are required for testing the null hypothesis are described. Application of the methods is made to leukemia data for central New York State.  相似文献   
540.
Modeling Prescribed Surface-Fire Regimes for Pinus strobus Conservation   总被引:2,自引:0,他引:2  
Abstract:  We developed a simple model of   Pinus strobus L. stand dynamics to compare the impacts of different temporal arrangements of surface fires designed to reflect the application of fire as both an essential ecosystem process (natural fire) and as an efficient means of producing specific habitat features or other values (optimal fire). We used a stochastic simulation model of fire processes to estimate the mean fire-return interval that would maximize stand structural diversity. We investigated trade-offs between structural diversity and temporal population stability associated with changes in the fire interval and used a deterministic version of the model to explore the effects of scheduling fires at fixed intervals. In stochastic simulations, maximum structural diversity occurred at intermediate levels of disturbance (40-year mean fire interval). When fires were scheduled at fixed intervals, a longer, 100-year return interval maximized diversity. Mean fire-return interval was a mitigating factor in the diversity-stability relationship, which changed from positive to negative as the fire interval was reduced progressively from 250 to 5 years. As an alternative to scheduling fires at specified mean intervals, we developed a goal-programming model (a form of linear programming model) and used it to identify an optimal fire schedule for achieving habitat and visual-quality objectives. In comparison with the 40-year stochastic mean fire interval, which maximized structural diversity, the optimal schedule produced comparable levels of both diversity and fire frequency. Our results show how simulation and goal-programming models can be used to evaluate prescribed fire-scheduling alternatives and to explore the comparative advantages of natural and optimal fire-management approaches.  相似文献   
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