用最长连续无降水日建立宁夏的干旱预测概念模型

在相关普查及分析各因子物理意义的基础上,建立了宁夏不同程度干旱预测的概念模型,结果表明,影响宁夏全区不同程度干旱的大气及海洋强信号并不一定是线性关系,与大气及海洋各系统之间的相互配置,特别是高层与低层之间、中高纬与低纬之间、大气与海洋之间、各大气与海洋系统的强、弱之间及相对位置之间的配置等都有着非常重要的关系。     

Effects of aluminum on physiological metabolism and antioxidant system of wheat (Triticum aestivum L.)

We have found that rice bran effectively adsorbed chloroform from tap water. The amount of chloroform adsorbed was plotted against the equilibrium concentration of chloroform in solution on a logarithmic scale. A linear relationship was obtained, indicating that the adsorption reaction was a Freundlich type. The removal of chloroform by rice bran was attributed to the uptake into intracellular particles called spherosomes.     

The trends of composite environmental indices in Korea

In this paper we construct for the first time an annual Composite Environmental Index from 1986 to 1995 in Korea, which is useful for evaluating the efficiency of environmental policies. Nine types of environmental problems are examined. On average, the composite index has increased annually by 5.3% over the 1986-1995 period, which implies that overall environmental quality has deteriorated gradually during this period. Problems such as the greenhouse effect, loss of biodiversity, natural resource depletion, and ecotoxication led to deterioration of environmental quality in the 1990s.     

油田人工岛开发建设风险控制措施分析

针对油田人工岛开发的特点,通过对人工岛开发建设过程的风险分析与对策研究,制定出有效的预防措施,以保证人工岛开发建设的顺利进行.     

绿化带对氯气泄漏扩散影响的模拟研究

基于FLUENT软件的物质传输模块建立了氯气泄漏扩散模型.考虑绿化带对氯气泄漏扩散的影响,针对不同的绿化带高度、泄漏速度和风速对氯气泄漏扩散进行了数值模拟.结果表明,绿化带对氯气的泄漏扩散有阻碍作用;绿化带高度越高越容易减缓危险区域在水平方向的传输;泄漏速度增加,危险区域的浓度值增高;风速增加,危险区域的浓度值减小,而...     

Determination of the swimming trajectory and speed of chain-forming dinoflagellate <Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis> with digital holographic particle tracking velocimetry

The marine dinoflagellate Cochlodinium polykrikoides is a harmful and highly motile algal species. To distinguish between the motility characteristics of solitary and chain-forming cells, the swimming trajectories and speeds of solitary cells and 2- to 8-cell chains of C. polykrikoides were measured using a digital holographic particle tracking velocimetry (PTV) technique. C. polykrikoides cells exhibited helical swimming trajectories similar to other dinoflagellate species. The swimming speed increased as the number of cells in the chain increased, from an average of 391 μm s⁻¹ (solitary cells) to 856 μm s⁻¹ (8-cell chain). The helix radius R and pitch P also increased as the number of cells in the chain increased. R increased from 9.24 μm (solitary cell) to 20.3 μm (8-cell chain) and P increased from 107 μm (solitary cell) to 164 μm (8-cell chain). The free thrust-generating motion of the transverse flagella and large drag reduction in the chain-forming cells seemed to increase the swimming speed compared to solitary cells. The measured swimming speeds agreed with those from field observations. The superior motility of chain-forming C. polykrikoides cells may be an important factor for its bloom, in addition to the factors reported previously.     

Application of eggshell waste for the immobilization of cadmium and lead in a contaminated soil

Liming materials have been used to immobilize heavy metals in contaminated soils. However, no studies have evaluated the use of eggshell waste as a source of calcium carbonate (CaCO₃) to immobilize both cadmium (Cd) and lead (Pb) in soils. This study was conducted to evaluate the effectiveness of eggshell waste on the immobilization of Cd and Pb and to determine the metal availability following various single extraction techniques. Incubation experiments were conducted by mixing 0–5% powdered eggshell waste and curing the soil (1,246 mg Pb kg^?1 soil and 17 mg Cd kg^?1 soil) for 30 days. Five extractants, 0.01 M calcium chloride (CaCl₂), 1 M CaCl₂, 0.1 M hydrochloric acid (HCl), 0.43 M acetic acid (CH₃COOH), and 0.05 M ethylendiaminetetraacetic acid (EDTA), were used to determine the extractability of Cd and Pb following treatments with CaCO₃ and eggshell waste. Generally, the extractability of Cd and Pb in the soils decreased in response to treatments with CaCO₃ and eggshell waste, regardless of extractant. Using CaCl₂ extraction, the lowest Cd concentration was achieved upon both CaCO₃ and eggshell waste treatments, while the lowest Pb concentration was observed using HCl extraction. The highest amount of immobilized Cd and Pb was extracted by CH₃COOH or EDTA in soils treated with CaCO₃ and eggshell waste, indicating that remobilization of Cd and Pb may occur under acidic conditions. Based on the findings obtained, eggshell waste can be used as an alternative to CaCO₃ for the immobilization of heavy metals in soils.     

Site selection of check dams using geospatial techniques in Debre Berhan region,Ethiopia — water management perspective

Environmental Science and Pollution Research - Remote sensing and GIS technology were very helpful to determine an appropriate location of freshwater storage in Amhara, Ethiopia. The techniques...     

海岸侵蚀灾害评估方法探讨

探讨了海岸侵蚀灾害的评估方法,以及评估指标的选取和灾级的划分,特别提出了利用综合指数进行灾害评估的建议,采用１９９２年山东省海岸侵蚀灾害的有关资料和１９９１年有关区县的经济指标,对海岸侵蚀灾害进行了评估,采用经济总损失量,单位岸线损失量,人均损失量,国民生产总值损失率,国民收入损失率,预算内收入损失率,受灾率和土地损失等指标作为评估参数,将海岸侵蚀灾害分为特大灾,大灾,中灾,小灾,轻灾五种,依法给