西安f7地裂缝发展变化的预测研究

论文首先分析和总结了影响西安地裂缝发展变化的主要人为因素。随后,利用三维非稳定渗流分析方法研究了人类活动对地下水位的影响;根据西安市新增固定资产投资的变化,预测了地面荷载的变化;以时间、地下水位和地面荷载为基本变量,建立了预测f 7地裂缝活动趋势的BP神经网络模型;最后,借助MATLAB语言进行编程,利用训练稳定的网络模型,预测了f 7地裂缝的活动趋势以及年平均的垂直位移沉降量,为进一步研究西安地铁2号线安全运行和防护提供参考依据。     

Inventory and vertical migration of 90Sr fallout and 137Cs/90Sr ratio in Spanish mainland soils

In this paper the inventory of ⁹⁰Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m² and 2047 Bq/m². From these data set and those ¹³⁷Cs data obtained in a previous work the ¹³⁷Cs/⁹⁰Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for ¹³⁷Cs an average value 57% lower than that obtained for ⁹⁰Sr.Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of ⁹⁰Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm²/year, respectively.     

中国水权配置效率分析

基于整个社会的视角,对水权交易效率进行公理化分析,为水权交易的深入研究奠定基础.首先,提出分析的假设条件,定义水权配置效率,该效率满足完备性、传递性公理.其次,定义水权边际价值、总价值,提出水权边际价值递减规律.再次,给出水权配置的帕累托最优定义,提出帕累托最优时水权配置状态的定理,并论证水权的帕累托配置是稳定的水权配置状态.根据极限理论,给出水权配置序列收敛于帕累托最优配置的定义,论证了在现实水权信息不对称的情况下,只有通过水权交易重新配置水权才能逼近水权配置的最优状态--帕累托配置,而依靠行政配置无法实现.最后,采用本文理论分析我国水权交易现状,指出由于我国目前水权交易成本过高,水权配置向帕累托逼近的速度慢,水权配置无法达到帕累托最优.随着我国水权交易制度的日趋完善,水权配置将达到帕累托最优,从而实现水资源的充分利用.     

长江干流不同江段鱼卵及仔鱼漂流特征昼夜变化的初步分析

根据2007~2009年在长江干流的泸州、珞璜、宜都、武穴4个江段分别采集的数据,对这些江段鱼卵及仔鱼漂流特征的昼夜变化规律进行初步分析。结果显示,长江上游泸州江段和珞璜江段鱼卵及仔鱼昼夜漂流密度有一定差异,但不显著;长江中游宜都江段,鱼卵漂流密度在昼夜时间上有显著性差异（〖WTBX〗n=38,p〖WTBZ〗=000）,表现为6〖DK〗∶00的平均漂流密度13.02 ind./100 m3明显大于18〖DK〗∶00的密度3.28 ind./100 m3,仔鱼夜间漂流密度明显大于白天,于22〖DK〗∶00达到高峰值;武穴江段仔鱼漂流密度在昼夜时间上有显著性差异（〖WTBX〗n=62,p〖WTBZ〗=000）,8〖DK〗∶00的平均漂流密8621 ind./100 m3明显大于18〖DK〗∶00的密度4485 ind./100 m3。不同物种的鱼卵及仔鱼漂流密度亦呈现出一定的昼夜差异,宜都江段贝氏〖FK（W*5/5。1〗〖PS黎明政造字2.EPS;%84%84,BP〗〖FK)〗,草鱼和银鲴鱼卵主要分布在白天,鳙、鲢等种类分布在夜间;另外,鳙、银鮈、铜鱼和翘嘴鲌等多数种类的仔鱼仅在夜间有分布,而飘鱼属的种类主要分布在白天。通过采集到鱼卵发育期推算,四大家鱼、贝氏〖FK（W*5/5。1〗〖PS黎明政造字2.EPS;%84%84,BP〗〖FK)〗、银鲴和翘嘴鲌的繁殖时间主要集中在夜间,而花斑副沙鳅和鳊全天均有繁殖     

Tissue distribution of Dechlorane Plus and its dechlorinated analogs in contaminated fish: high affinity to the brain for anti-DP

Information on tissue distribution of Dechlorane Plus (DP) and its dechlorinated analogs in wildlife is scarce. DP isomers and two dechlorinated compounds, anti-Cl₁₁-DP and anti-Cl₁₀-DP, were examined in the muscle, liver, and brain tissues of two bottom fish species collected from an electronic waste recycling site, South China. The median levels of syn-, anti-, and anti-Cl₁₁-DP isomers in the tissues ranged 0.18-39.1, 0.22-52.9, and 0.01-5.63 ng/g wet wt, respectively. Anti-Cl₁₀-DP was only detected in one muscle sample of mud carp (0.01 ng/g wet wt), although it was consistently detected in the sediments (0.42-0.83 ng/g dry wt). Preferential distribution in liver relative to muscle was observed for syn-DP and anti-Cl₁₁-DP. However, a high persistent retention in the brain compared to the liver was observed for anti-DP, suggesting that this isomer can across the blood-brain barrier of fish, and may cause adverse effects to the nervous system in the exposed biota.     

Spatial distribution of ciguateric fish in the Republic of Kiribati

Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50 000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n = 41], 8% [n = 13] and 68% [n = 117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g⁻¹). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n = 3-19) were toxic. Toxicity varied within species and among locations by up to 10 000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g⁻¹ threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n = 6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.     

PCB accumulation and tissue distribution in cave salamander (Proteus anguinus anguinus, Amphibia, Urodela) in the polluted karstic hinterland of the Krupa River, Slovenia

For over two decades, a manufacturer of electrical capacitors disposed of its waste within the karstic hinterland of the Krupa River (Slovenia) resulting in the surroundings becomming heavily polluted with PCB. Albeit the extent of the contamination has been known since 1983 and the Krupa River has become one of the most PCB polluted river in Europe, the effects on the cave fauna of the region remain unknown. The most famous cave dweller of the Krupa hinterland is the endemic cave salamander Proteus anguinus anguinus. In this study we determine the levels of PCB in the tissues of the Proteus and in river sediments. The total concentration of PCB in individual tissue samples from specimens of the Krupa spring was between 165.59 μg g⁻¹ and 1560.20 μg g⁻¹ dry wt, which is at least 28-times higher than those from an unpolluted site. The kidneys contained the lowest concentration, while the highest concentration was in subcutaneous fat and tissues with high lipid contents like visceral fat and liver. Total PCB concentrations in sediment samples from the Krupa River were between 5.47 and 59.20 μg g⁻¹ dry wt showing that a high burden of PCB still remains in the region. The most abundant PCB congeners in all analyzed samples were di-ortho substituted (PCB #101, #118, #138 and #158), but higher proportion of mono-ortho PCB was present in sediments. The ability of Proteus to survive a high PCB loading in its environment and especially in its tissues is remarkable. Its partial elimination of low chlorinated and mono-ortho substituted congeners is also reported.     

Atmospheric particle characterization, distribution, and deposition in Xi'an, Shaanxi Province, Central China

Physical characterization and chemical analysis of settled dusts collected in Xi’an from November 2007 to December 2008 show that (1) dust deposition rates ranged from 14.6 to 350.4 g m⁻² yr⁻¹. The average deposition rate (76.7 g m⁻² yr⁻¹) ranks the 11th out of 56 dust deposition rates observed throughout the world. The coal-burning power was the major particle source; (2) on average (except site 4), ∼10% of the settled dusts having size <2.6, ∼30% having size <10.5, and >70% having size <30 μm; (3) the concentrations for 20 out of 27 elements analyzed were upto 18 times higher than their soil background values in China. With such high deposition rates of dusts that contain elevated levels of toxic elements, actions should be taken to reduce emission and studies are needed to assess the potential impacts of settled particles on surface ecosystem, water resource, and human health in the area.     

河道沉积物中磷的分布、吸附及释放规律研究

为科学评价磷在河道沉积物中的环境行为,在模拟条件下研究了上海市进木港和苏州河沉积物中磷的分布形态、吸附特征及释放规律.结果表明:(1)2种沉积物中碎屑钙磷(De-P)浓度最高,闭蓄态磷(Oc-P)次之,其他形态磷浓度相对较低,而活性磷中以铁磷(Fe-P)为主;(2)2种沉积物对磷的吸附均符合线性方程,在4.0h时基本达...     

混凝一气浮控制三卤甲烷生成势的研究

研究了混凝一气浮工艺对不同分子量区间三卤甲烷生成势（trihalomethanes formation potential,THMFP）的去除效果及絮体形态对THMFP去除效果的影响。结果表明,混凝一气浮工艺以去除大分子量区间THMFP为主,对小分子量区间THMFP的去除效果较差。UV254值与THMFP值的线性相关系数为0．9449,UV254值可以较好地反映THMFP的含量。絮体的分形维数为1．17～1．2时,孔隙率较大,可增加絮体对THMFP的活性吸附空间,且絮体相对密度较小,可增强同向絮凝作用,增加絮体和THMFP的接触概率,有利于气浮对THMFP的去除。