分形模型在黑龙江漠河地区金矿成矿预测中的应用

以漠河地区4 830个样品的化探数据为基础,采用“Ｃ-Ａ”(含量-面积)分形模型,通过对Au、Cu、Zn、Pb分维计算,揭示出各元素空间分布的分形结构特征和无标度区范围,得出Au、Cu、Zn、Pb元素化探异常下限值分别为3.1×10^-9、28.1×10^-6、114.1×10^-6、28.4×10^-6,圈定出33个金异常区。根据金异常区与主要地质要素及Cu、Zn、Pb异常区的关系,确定远景区分布于白卡鲁山－长缨站、笔架山－马林林场、蒙克山－防火站、富乐－阿木鲁山,共8个区域具有金矿找矿前景。预测结果表明,5个已知金矿化点落入其中2个预测区内,其余6个预测区中呈无已知矿化点,但具有找矿前景。     

Are Models Too Simple? Arguments for Increased Parameterization

The idea that models should be as simple as possible is often accepted without question. However, too much simplification and parsimony may degrade a model's utility. Models are often constructed to make predictions; yet, they are commonly parameterized with a focus on calibration, regardless of whether (1) the calibration data can constrain simulated predictions or (2) the number and type of calibration parameters are commensurate with the hydraulic property details on which key predictions may depend. Parameterization estimated through the calibration process is commonly limited by the necessity that the number of calibration parameters be smaller than the number of observations. This limitation largely stems from historical restrictions in calibration and computing capability; we argue here that better methods and computing capabilities are now available and should become more widely used. To make this case, two approaches to model calibration are contrasted: (1) a traditional approach based on a small number of homogeneous parameter zones defined by the modeler a priori and (2) regularized inversion, which includes many more parameters than the traditional approach. We discuss some advantages of regularized inversion, focusing on the increased insight that can be gained from calibration data. We present these issues using reasoning that we believe has a common sense appeal to modelers; knowledge of mathematics is not required to follow our arguments. We present equations in an Appendix, however, to illustrate the fundamental differences between traditional model calibration and a regularized inversion approach.     

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). Delta15N and delta13C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health.     

The nature of scour development and scour protection at offshore windfarm foundations

Analysis and interpretation of monitoring data for the seabed bathymetry local to offshore windfarm foundations has shown how the scour develops in time and highlighted variations between sites with different seabed sediment characteristics, i.e. sands and clays. Results from European offshore windfarms have generated a unique dataset for comparison with previously published data. Where surficial sediment is underlain by a marine clay the scour (to date) has been limited, whilst those with unconstrained depths of sandy sediments show scour as deep as 1.38 times the monopile diameter. Scour protection has been installed at some sites for structural stability of the foundation or for cable protection. The flow interaction with the protection causes edge scour or secondary scour in the seabed around the protection. In some cases this scour is deeper than the unprotected case. The analysis has resulted in an improved evidence base for scour in the marine environment.     

离子色谱法测定臭氧化饮用水中的痕量溴酸盐

溴酸盐是饮用水臭氧化反应产生的副产品之一。美国环保机构认为溴酸盐的量应限制在低至μｇ／Ｌ水平。利用本试验开发的离子色谱技术可定量分析此含量范围的溴酸盐，甚至在高含量的阴离子（如氯化物和硫酸盐）共存的情况下也受干扰。