Na+,K+,Mg2+/NO3-,Cl-,SO42--H2O体系25 ℃热力学模型和溶解度预测Ⅱ:四元体系Na+,K+/NO3-,Cl——H2O的Pitzer混合参数及其应用

在前文讨论并获得了用于该六元体系溶解度计算合理的单独电解质Pitzer参数后,介绍Na+,K+/Cl-,NO3--H2O四元体系混合参数的获得及其在体系溶液热力学性质和溶解度预测中的应用。     

Sieve mesh size and quantitative chironomid paleoclimatology

The minimum sieve mesh size for fossil chironomid analysis is usually set at 100 μm, to ensure adequate recovery of small species. Yet taking into account the labor intensity of sorting and identifying fossil chironomid remains, the large numbers of samples requiring processing in paleoclimate studies with high temporal resolution, and the increasing need to engage non-specialist analysts in this work, it seems appealing to sieve samples through a larger mesh size that would mainly retain easier-to-see, easier-to-extract and easier-to-identify fossil specimens. In this study we evaluated the influence of sieve mesh size on chironomid-based quantitative paleoenvironmental reconstructions in African lakes. We developed two chironomid-salinity calibration data sets based on either the >100 μm or >150 μm size fractions of surface-sediment fossil assemblages, and compared the performance of salinity-inference models derived from them. We find that, despite ∼35% additional fossil loss, restriction to >150 μm data did not appreciably affect individual taxon optima or tolerances, and resulted in only a modest reduction of mean taxon richness per lake. Parameters of statistical model performance were as good, or better than those of models based on the >100 μm data, albeit only after excluding two atypically dilute (<100 μS/cm) lakes from the calibration. Application of inference models based on >150 μm or >100 μm data to a 200-year fossil record from Lake Abiyata, Ethiopia, produced very similar trends, amplitudes and uncertainty ranges of inferred past salinity change. Restriction to >150 μm data reduced the mean fossil yield of core samples by ∼20% on average, i.e. fossil loss was markedly lower than in surface-sediment samples. Using the larger mesh size reduced sample processing time by up to 50%, partly by removing a significant proportion of visually obstructive organic debris, and partly by allowing a greater fraction of chironomid fossils to be identified directly in the sorting tray. The fraction of 1st instar group taxa in surface-sediment samples was reduced from 13% to 3%, increasing the mean taxonomic resolution of fossil assemblages, and thus their ecological specificity.     

ArcGIS中几种空间内插方法的比较

ArcGIS软件的GA(Geostatistical Analyst)分析扩展模块是一个功能强大、简单易用的数据分析与表面建模工具,应用领域广泛。这里首先简单地介绍了该模块中四类主要的空间内插方法,随后结合该模块的实际界面介绍了该方法的使用,并通过示例比较了几种空间内插方法的优缺点。GA分析扩展模块能用少量的采样数据点的测量值生成连续表面,预测表面的生成、预测表面的准确度和预测表面的误差估计对建模以及分析有重大的意义。     

The crust and upper mantle structure beneath southeastern China

We analyzed teleseismic waveforms recorded by 44 stations in the Fujian and Taiwan provinces of China and obtained 5344 high quality receiver functions. The crustal thickness (H) and average crustal V_P/V_S ratio (k) beneath every station were estimated using the H–k stacking method. Crustal thicknesses near the Fujian Province range from 28.3 to 32.8 km with an average of 31.1 km, and the corresponding V_P/V_S ratios vary from 1.70 to 1.84 with a mean of 1.76. From inland to offshore of the Fujian Province, the crustal thicknesses decrease and Poisson's ratios increase. These may indicate decreasing SiO₂ and increasing calc-alkaline contents in the crust. The discontinuity structures such as the Moho, subducting slab, the 410- and 660-km discontinuities (hereafter we call them the 410 and the 660) are also studied using common converted point (CCP) stacking of receiver functions. Along two NW–SE lines of central and northern Taiwan, the CCP stacking results show a western dipping structure at depths above 50 km, suggesting that the Philippine Sea plate is probably subducting beneath the Eurasian continent plate near the central and northern Taiwan. The CCP stacking results show sharp and flat 410- and 660-km discontinuities, and the transition zone thickness (TZT) is the same as that of ambient mantle beneath Fujian and Taiwan Strait, but thickens in the east of Taiwan. These results suggest that (1) the subducting Eurasian continent plate is confined to the depths above 410 km beneath Fujian and Taiwan Strait; and (2) the South China Sea slab may reach the transition zone beneath the east of Taiwan.     

A notch structure on the Moho beneath the Eastern San Gabriel Mountains

Synthetic waveform modeling of the anomalous receiver functions for two stations in the eastern San Gabriel Mountains, California, suggests that a flat-topped notch structure exists on the Moho. North of the San Andreas Fault (SAF), the Moho depth is 36–38 km and is 33–35 km south of the San Gabriel Fault (SGF), but in-between under the Mt. Baldy block, it is only  29 km. The inferred notch structure is also supported by the Pms arrival times along the SCSN and the LARSE I profiles. The shallow Moho block correlates well with the surficial exposure of the lower plate Pelona Schist or where it resides at very shallow depth. The large Moho offsets across the two major faults can be either related to differential uplifting reflected by the difference in the denudation rate and the exposure of the lower plate Pelona Schist, or it can be the result of the juxtaposition of the distinctive terranes with initially different Moho depth due to the strike-slip movements along the two major faults.     

A two-phase grey fuzzy optimization approach for water quality management of a river system

An extension of the Grey Fuzzy Waste Load Allocation Model (GFWLAM) developed in an earlier work is presented here to address the problem of multiple solutions. Formulation of GFWLAM is based on the approach for solving fuzzy multiple objective optimization problems with max–min as the operator, which usually may not result in a unique solution. The multiple solutions of fuzzy multiobjective optimization model should be obtained as parametric equations or equations that represent a subspace. A two-phase optimization technique, two-phase GFWLAM, is developed to capture all alternative or multiple solutions of GFWLAM. The optimization model in Phase 1 is exactly same as the optimization model described in GFWLAM. The optimization model in Phase 2 maximizes the upper bounds of fractional removal levels of pollutants and minimizes the lower bounds of fractional removal levels of pollutants keeping the value of goal fulfillment level same as obtained from Phase 1. The widths of the interval-valued fractional removal levels play an important role in decision-making as these can be adjusted within their intervals by the decision-maker considering technical and economic feasibility in the final decision scheme. Two-phase GFWLAM widens the widths of interval-valued removal levels of pollutants, thus enhancing the flexibility in decision-making. The methodology is demonstrated with a case study of the Tunga-Bhadra river system in India.     

基于小波萎缩方法的图像小波去噪的研究

小波方法越来越广泛地应用到图像处理当中。小波萎缩方法是小波图像去噪方法中较为重要的方法之一。本文主要介绍了图像小波去噪中较常用的小波萎缩方法，并主要针对Bayes阈值，使用噪声方差邻域估计法加以研究和实现，并将几种阈值函数的去噪效果进行了对比。     

Estimating site-specific strong earthquake motions

The Campus Earthquake Program (CEP) of the University of California (UC) started in March 1996, and involved a partnership among seven campuses of the UC—Berkeley, Davis, Los Angeles, Riverside, San Diego, Santa Barbara, Santa Cruz—and the Lawrence Livermore National Laboratory (LLNL). The aim of the CEP was to provide University campuses with site-specific assessments of their earthquake strong motion exposure, to complement estimates they obtain from consultants according to the state-of-the-practice (SOP), i.e. Building Codes (UBC 97, IBC 2000), and Probabilistic Seismic Hazard Analysis (PSHA). The Building Codes are highly simplified tools, while the more sophisticated PSHA is still somewhat generic in its approach because it usually draws from many earthquakes not necessarily related to the faults threatening the site under study.Between 1996 and 2001, the site-specific studies focused on three campuses: Riverside, San Diego, and Santa Barbara. Each campus selected 1–3 sites to demonstrate the methods and procedures used by the CEP: Rivera Library and Parking Lots (PL) 13 and 16 at UCR, Thornton Hospital, the Cancer Center, and PL 601 at UCSD, and Engineering I building at UCSB. The project provided an estimate of strong ground motions at each selected site, for selected earthquake scenarios. These estimates were obtained by using an integrated geological, seismological, geophysical, and geotechnical approach, that brings together the capabilities of campus and laboratory personnel. Most of the site-specific results are also applicable to risk evaluation of other sites on the respective campuses.The CEP studies have provided a critical assessment of whether existing campus seismic design bases are appropriate. Generally speaking, the current assumptions are not acknowledging the severity of the majority of expected motions. Eventually, both the results from the SOP and from the CEP should be analyzed, to arrive at decisions concerning the design-basis for buildings on UC campuses.     

European lake shores in danger — concepts for a sustainable development

In Europe, when small (> 0.01 km²) lakes are considered, approximately 500,000 natural lakes occur. This considerable number points to the fact that lakeshore habitats and ecosystems are of significant importance to the total biodiversity of European landscapes, not only because of their expanse, but also because they are ecotones between land and water, which attract many kinds of wildlife, economical, cultural and recreational uses and human settlement. These very considerable stretches of shore are not currently registered, mapped or evaluated anywhere.Apart from providing habitat, the littoral biocoenosis performs a string of additional functions in the ecosystem, of which several are also of great importance to people, such as self purification, buffer zone, erosion protection and recreation scenery. In particular, the recreational function provides a main economic base for many lake areas and even whole countries in Europe. However, human interests have resulted in lake shore deterioration, such that many European lakes are now bare natural shores or retain only relics of them. Apart from the loss of the ecological functions, this also leads to a substantial loss of economic benefits. This precipitates the need for a responsible management, which can be done only on the base of a sound assessment method and a continuous monitoring of the status of lake shore areas. On a European scale, the European Water Framework Directive (WFD, 2000/60/EC) and the Habitat Directive (92/43/EEC) provide the frame for the assessment and monitoring of the status of littoral habitats of lakes. The WFD focuses on entire surface water bodies, including their associated wetlands under influence of their natural water-level fluctuations. However, the provided set of quality elements has to be adapted for an approach specific to lake shores. Apart from quality elements indicating the natural spatial pre-requisites, biocoenotic diversity and integrity, and ecosystem function and dynamics, also quality elements representing the human pressure of land use and the social and economic value of the lake shore zone should be included in an integrated lakeshore assessment and monitoring concept.However, the application of such an integrated quality assessment scheme requires an integrated administrative counterpart, just as the WFD requires for water management aspects on a catchment scale. Only by overcoming the splitting of competence among a variety of authorities and planning corporations can an integrated approach to sustainable shore development be translated into action.     

S-wave velocity structure inferred from receiver function inversion in Tengchong volcanic area

IntroductionTengchongvolcanicclusterisoneofthefamousvolcanicactiveareasinourcountry.LocatedatthenortheasternsideoftheimpingingmarginofIndianandEurasiaplates,TengchongvolcanicareabelongstoBurmaarc-shapeseismictectonicsystemofHimalayasstrongseismicactivezone.Thiskindofcomplextectonicenvironmentmakesitanareaoffrequentearthquake,volcanoandhotspringactivitiesforonewhole.Itisoneoftheyoungestvolcanicareasinourcountrywithmorevolcanoes,widerangeandcompleteeruptionstyles.Thevolcanoactedfrequentlyfrom…