用CSR4.0+CS模型计算海潮负荷改正

介绍了CSR3．0与CSR4．0 CS海潮模型，并对两模型进行了分析和实算比较，认为CSR4．0 CS比CSR3．0海潮模型精度更高，在计算中国测站海潮改正时，顾及中国近海海潮图是必要的。对我国第二期水准路线用CSR4．0 CS模型计算了海潮负荷改正，结果表明：海潮负荷对高精度水准测量的影响，主要取决于水准路线的近海位置，越是近海地区越明显；在近海区域，这项改正不能忽略。     

双Packer系统在鄂尔多斯盆地地下水勘查中的应用

双Packer系统在鄂尔多斯盆地地下水勘查中的应用,为在该盆地开展深层地下水水化学同位素的研究,提供了一个有效的工具。了解该系统的工作原理、应用条件和在鄂尔多斯盆地地下水勘查中的具体应用,对在我国水文界普及该技术具有重要意义。     

Trip making, induced travel demand, and accessibility

Traditional transportation planning practice rests on the premise that the demand for transportation is derived. On the other hand, economic theory advances that enhancement to the transportation system leads to lower travel cost and hence to induced demand. Such an argument lends support to the view that the rate at which trips are generated is linked to the ease of making trips to potential destinations. Rather conflicting evidence has so far come out of aggregate trip generation modeling applications. This paper revisits this issue with proper characterization of integral accessibility. Poisson regression models of automobile trip generation by trip purpose are estimated on travel survey data in Minneapolis–St. Paul, MN. Alternative measures of accessibility are tested for statistical significance. Conclusions are drawn on the role of accessibility in trip making and on the comparison of integral accessibility measures.The first author gratefully acknowledges the financial support of NSF grant SBR- 9308394. We are particularly indebted to Rick Gelbmann, Robert Paddock, and Mark Philippi at the Metropolitan Council, Minneapolis–St. Paul, and William Barrett at the Office of Transportation Data Analysis, Minnesota Department of Transportation for their availability to answer all our data-related questions.     

A determination of the composition of the Saturnian stratosphere using the IUE

We reduced ultraviolet spectra of Saturn from the IUE satellite to produce a geometric albedo of the planet from 1500 to 3000 Å. By matching computer models to the albedo we determined a chemical composition consistent with the data. This model includes C₂H₂ and C₂H₆ with mixing ratios and distributions of (9 ± 3) × 10^?8 in the top 20 mbar of the atmosphere with none below for C₂H₂ and (6 ± 1) × 10^?6 also in the top 20 mbar with none below for C₂H₆. The C₂H₂ and C₂H₆ distributions and the C₂H₆ mixing ratio are taken directly from the Voyager IRIS model [R. Courtin et al., Bull. Amer. Astron. Soc.13, 722 (1981), and private communication]. The Voyager IRIS model also includes PH₃, which is not consistent with the uv albedo from 1800 to 2400 Å. Our model requires a previously unidentified absorber to explain the albedo near 1600 Å. After considering several candidates, we find that the best fit to the data is obtained with H₂O, having a column density of (6 ± 1) × 10^?3 cm-am.     

THE RESEARCH ON THE DISTRIBUTION AND FORMS OF HEAVY METALS IN THE XIANGJIANG RIVER SEDIMENTS

In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.     

Wind tunnel simulation experiment and investigation on the electrification of sandstorms

~~Wind tunnel simulation experiment and investigation on the electrification of sandstorms~~     

Web-based application for estimating water quality impacts due to environmental dredging

A Web-based dredge plume simulation software has been developed for estimating sediment transport and contaminant release from dredging operations. This application software comprises a near-field source model and far-field sediment transport model, combined with the settling analysis of flocculent particles. It is designed to run on all computing platforms with a standard Web browser and is accessible over the Internet. This paper describes its internal software structures and the major features of the application software. In addition, an example application of sediment transport in the Savannah River, GA, is included to illustrate typical input and output screens and to demonstrate the accuracy of the model. The water quality assessment software developed herein will greatly enhance the ability of the predictive tool for estimating sediment transport and resuspension during dredging operations.     

The low seismic activity of the Korean Peninsula surrounded by high earthquake countries

Although the Korean Peninsula is locatednear several great earthquake regions suchas NE China and SW Japan, it has neversuffered from catastrophic earthquakes forthe last 2000 years according to historicaland instrumental records. We investigatedthe low seismicity of Korea based on thehypothesis of the Baikal-Korea Plate (BKP)or Amurian Plate movement which isinitiated by the Baikal Rift Zone spreadingin a southeastward motion with acounter-clockwise rotation due to thecollision of the Indian Plate against theEurasian Plate. Many disastrous earthquakesof NE China, SW Japan and Sakhalin releaselarge amounts of seismic energy along theboundary of the Baikal-Korea Plate. It isnecessary to compute the released seismicenergy along the presumed boundary of theBaikal-Korea Plate compared to the KoreanPeninsula in order to estimate themicro-plate boundary. The total energyreleases (1900–1999) from the majordisastrous earthquakes (M6.0) alongthe Baikal-Korea plate are about10³–10⁴ times as much as theKorean Peninsula (M3.0). The focalmechanisms for the intra-continentalearthquakes near and/or along theBaikal-Korea Plate boundary of NE China, SW Japan, Sakhalin and Mongolia mostlyrepresent the horizontal motions of theright-lateral strike slip type, indicatingthat the Baikal-Korea Plate is acounter-clockwise and transcurrent motion. The relative displacement vectors of GPS(global positioning system) also indicatedthat the Baikal-Korea Plate movescounter-clockwise around the KoreanPeninsula. These factors may indicate thatthe Korean Peninsula is not located at thePlate boundary, but just within a margin ofthe Baikal-Korea Plate which movessoutheastward with a counter-clockwiserotation from the Baikal Rift Zone in NEAsia. Therefore there is no enoughaccumulated strain to generate largeearthquakes in the Korean Peninsula and itmakes the Korean Peninsula free fromseismic hazard of large catastrophicearthquakes.     

On the evolution and histology of some Cambrian protoconodonts,paraconodonts and primitive euconodonts

Although the history of Cambrian conodont study goes back to a century ago, it was not until 1959 that the systematic study of Cambrian conodonts was initi-ated[1]. During the last 44 years Cambrian conodonts have been well documented from all continents but Africa. However, the morphological evolution of para- conodonts and protoconodonts have been subjected to less study than the primitive euconodonts in the inter-val across the Cambrian-Ordovician boundary. Miller (1984) proposed a Weste…     

Interannual and long-term variation in the nearshore fish community of the mesohaline Hudson River estuary

The detection of long-term shifts in species composition and spatial structuring of aquatic communities may be obscured by high levels of interannual variation. Estuarine fish communities are likely to exhibit high levels of variation owing to the influence of riverine forcing and the importance of anadromous and transient species, whose abundances may not be locally controlled. We describe patterns of interannual variation and long-term shifts in the nearshore fish community of the mesohaline Hudson River estuary based on 21 yr of beach seine sampling conducted annually between late August and mid November. Of the 60 species encountered, the most abundant were Atlantic silversides (Menidia menidia), striped bass (Morone saxatilis), white perch (Morone americana), American shad (Alosa sapidissima), and blueback herring (Alosa aestivalis). Relationships between annual community composition and seasonal flow and temperature regimes were examined with canonical correspondence analysis. Annual variation was most closely correlated with river flows in the 3-mo period preceding fish sampling, indicating a persistent effect of environmental conditions on community structure. Despite significant interannual variation in composition, longer-term trends in community structure were observed. These included declines in catch rates of freshwater and estuarine species and a dramatic increase in the catch of Atlantic silversides, an annual marine species. Associated with these changes were declines in community diversity and increased compositional variation. These results indicate that analyses of temporal changes in community structure need to account for the multiple time scales under which forcing factors and community composition vary.