NaCl-KCl-H2O体系的体积性质及其与Pitzer模型的相关性研究

本文用高精度数字式振荡管密度计测定了288K至323K温度范围内NaCl?KCl混合溶液的密度,溶液的离子强度范围从0.1到4 mol.kg_^–1。用密度实验值计算了三元体系的超额体积并拟合得到了实验温度和浓度范围内的Pitzer模型参数,模型计算值与实验值的偏差在±0.0004 g.cm_^–3以内。用Pitzer模型计算了不同离子强度下三元体系在298.15K下的混合体积。     

Bioaccumulative Behaviour of Some PCB Congeners in Lake Geneva Brown Trout (Salmo trutta lacustris L)

Abstract

The bioaccumulation of PCBs has been studied for 60 Brown trout in Lake Geneva (Switzerland). The contamination level (1–3 ppm in wet weight, 10–30 ppm in lipid weight) is rather high.

Bioaccumulation curves (concentration as a function of the weight of the fish) have been established for 6 congeners and total PCBs. The total concentration of PCBs in wet weight increased with the weight of the fish; highly-chlorinated congeners (I.U.P.A.C. nr. 180, 2,3,4,5,2′,4′,5′-heptachlorobiphenyl) presented a faster, and lightly-chlorinated (I.U.P.A.C. nr. 28, 2,4,4′-trichlorobiphenyl) a slower, bioaccumulation tendency.

The total concentration of PCBs in lipid weight was constant, the concentration of congener 28 increasing and of congener 180 decreasing with the weight of the fish. This is attributed to the antagonistic effects of “growth and lipid dilution” and of the decrease of elimination kinetics as a function of the weight (and age) of the fish.

The partitioning theory and the pharmacokinetic approach are complementary methods for analysing this field data.     

Theoretical Study of the Scattering Resonance State, Reaction Mechanism and Partial Potential Energy Surface of the F＋CH4→HF ＋CH3 Reaction

Many reactions with fluorine atoms have the important applications in the areas of theatmosphere and the chemical lasers, such as the reaction of fluorine atoms with methane. F( 2 P) CH 4 (X1A1)→HF(X1 Σ ) CH 3 (X 2 A′′2) ?H0300k=-32.3 kcal mol ?1 It…     

Resuspension and Sedimentation of Particles from a Sediment Bed by Turbulent Jets

An experimental study was carried out to investigate the resuspension of heavy particles of a sediment bed by axi-symmetric turbulent jets issuing from below. The case of point jets and loosely-held monodispersed particles was considered, in particular, the cases of a single jet and an array of jets located in the intersection points of a square grid. The aim was to map the flow field and the nature of sediment distribution as a function of governing parameters and to parameterize salient observables such as the maximum height of rise of sediments. The results were extrapolated to study sediment resuspension in karstic lakes, especially lake Banyoles located in Catalonia, northeastern Spain.     

电厂冷却水在湖泊和水库中热扩散过程的数学模拟

本文对电厂冷却水排入湖泊和水库后的热扩散过程进行了数学模拟,建立了三维扩散方程,给出了一维、二维和三维计算湖泊和水库中任意点任意时刻水温上升量的计算公式,并通过实例对一维情形的计算公式进行了验证,结果很好.     

南疆博斯腾湖全新世环境演变特征的初步研究

根据南疆北部地区的博斯腾湖全世湖相沉积地层，孢粉及地化元素含量的分析结果表明，自约１２ｋａＢＰ以来，博斯腾湖地区的干旱环境特征一直存在，但期间仍有相对湿润的波动，表现为在北半球全新各次新冰期中，以旱生植物种类为主的孢粉浓度一般都呈现峰值，喜湿型的元素一般呈现相对高值，且剖面中的沉积物以泥炭发育为主，但在全新世大暖期中，暖湿的气候特征并不十分明显，博斯腾尖全新世环境的序列与北疆巴里坤湖，艾比湖及柴窝     

基于Landsat/TM影像提取太湖CDOM浓度空间分布

在湖泊生态系统中,CDOM(colored dissolved organic matter)是营养物质的重要来源,也是碳循环过程的主要物质组成.作者在2003年10月27日-28日太湖水质实验数据的基础上,研究与探讨了从Landsat/TM影像中提取太湖CDOM浓度分布状况的方法.通过研究可知,利用CDOM在TM1波...     

90Sr Content in Some Bottom Lake Samples

Abstract

Bottom sediments of two lakes in Bulgaria (Lake Iskar, Lake Pantcharevo) are investigated concerning the ⁹⁰Sr-content. The interpretation of the data shows that this region has been more affected by the Chernobyl accident than comparable soils in Japan.     

鄱阳湖区淡水蚌类多样性格局

通过采集标本,对鄱阳湖区淡水蚌类的多样性格局进行了研究。结果表明:所有采样区域淡水蚌类共有14属40种,中国特有种有32种,洞穴丽蚌、圆顶珠蚌和蚶形无齿蚌在各采样区域都有分布。太子河、饶河、修河、信江和赣江的淡水蚌类分别是10属23种、8属17种、10属14种、12属27种和13属     

唐家山堰塞湖泄洪问题研究

研究了唐家山堰塞湖的泄洪规律,并对其蓄水、溃坝、泛洪等三个过程进行了模型分析.