西北地区土壤资源特征及其开发利用与保护   总被引：10，自引：8，他引：2  

易秀  李侠 《地球科学与环境学报》2004,26(4):85-89

在分析西北地区土壤分布规律的基础上,研究了不同类型区土壤的资源特征及其在开发利用中存在的问题,认为黄土地区土壤土质疏松、粉砂含量高、富含碳酸钙是水土流失的物质基础;干旱区广为分布的荒漠土壤资源的性能低劣、绿洲区水土资源的利用比例失调是造成土地荒漠化、土壤盐渍化的根本原因;而高原土壤的粗骨性、土层浅薄、有效肥力低则加速了草场的退化和沙漠化.提出了西北地区土壤资源的合理利用与生态环境保护相协调的途经,即搞好农田基本建设,采用旱作技术节水和合理用水,扩大林草植被,保护天然草场和林木.并认为西北土壤资源的开发利用要在充分发挥其生产潜力的同时,首先应遵循生态规律,开发与保护并重,防止土壤资源衰竭和破坏.  相似文献   

南方涛动、热带海温与西北太平洋副高的联系     

方之芳  罗增森 《成都信息工程学院学报》1990,(1)

本文应用统计方法,首先探讨南方涛动指数与西北太平洋副热带高压的联系,然后分析赤道和热带太平洋区域海温对南方涛动的响应情况,同时分析南方涛动响应区域的海温与当时及滞后的西北太平洋副热带高压的联系,从中探讨南方涛动、厄尔尼诺海温异常及西北太平洋副热带高压之间的一种可能的相互作用机制。  相似文献   

中国稠油油田开发趋向     

顿铁军 《地球科学与环境学报》1993,(4)

我国稠油资源非常丰富,在东部和西部几个大油区均有分布,而且储量很大。近年来由于热采等先进技术的应用,使稠油开采得以发展,呈现出良好的前景。  相似文献   

Ice in the Southern Coalsack     

R. G.Smith †  R. D.Blum †  D. E.Quinn  K.Sellgren  D. C. B.Whittet † 《Monthly notices of the Royal Astronomical Society》2002,330(4):837-843

To better understand the conditions under which ice mantles form on grains in molecular clouds, three globules in the Southern Coalsack have been searched for the presence of H₂O ice. Given the total lack of star formation in the Coalsack, it is an ideal site for studying unprocessed icy molecular mantles. In our sample of eight field stars lying behind the Coalsack we detect strong H₂O ice absorption in the lines of sight to two stars and possible weak absorption in four others. We estimate H₂O ice column densities or upper limits for these lines of sight. Compared to dark clouds such as Taurus, the Coalsack H₂O ice column densities are lower than expected given the quiescent nature of the Coalsack region. It is possible that the chemical evolution of the Coalsack may simply be at too early a stage for significant ice mantles to appear on the grains, except perhaps in the densest parts of some of the globules. Alternatively, the presence or absence of ice absorption may be related to the distribution of dust along each line of sight, specifically, the relative contributions of dense globules and a more extended diffuse component. For example, our observations are consistent with an ice threshold extinction similar to that observed in the Taurus dark cloud if extinction amounting to   A _V∼5  towards Globules 2 and 3 arises in the extended component. Globule 1 appears to have no extended component.  相似文献   

Material exchange as heat engine for the corona-chromosphere transition region     

Ni Xiang-bin 《Chinese Astronomy and Astrophysics》1988,12(4):320-323

We think that a steady material exchange in the upper solar atmosphere can act as a heat engine that cools the corona and heats the corona-chromosphere transition region. We have considered heat conduction from the corona and radiation loss in the transition region and have calculated the temperature, density and velocity distributions in the transition region. Also discussed is the relation between the material flux, the velocity boundary value and the thickness of the transition region.  相似文献   

Primary proton spectrum around the knee deduced from the emulsion-chamber data obtained at Mts. Fuji and Kanbala     

J. Huang  N. Hotta  K. Kasahara  I. Ohta  S. Ozawa  T. Saito  M. Shibata  X. W. Xu  T. Yuda 《Astroparticle Physics》2003,18(6):637-648

We have done extensive Monte Carlo simulations using the new simulation codes of CORSIKA and COSMOS to compare with the gamma-family data obtained at Mts. Fuji (3750 m above sea level) and Kanbala (5500 m above sea level). Then, we estimated the primary proton and helium spectra around the knee energy region using a multiple-layered feed-forward neural network as a classifier of primary particle kind. The selection efficiency of proton-induced family events is estimated to be 82%. The flux value of protons at 2×10¹⁵ eV is (5.5±1.5)×10⁻¹⁴ (m⁻² s⁻¹ sr⁻¹ GeV⁻¹). The result suggests heavy-enriched primary composition around the knee region.  相似文献   

Precursory arrivals to PP     

Mamoru Kato  Kazuro Hirahara 《Geophysical Journal International》1991,106(3):551-557

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中国强震迁移与现代地壳波浪运动     

胡连英 《地球科学与环境学报》1988,(3)

本文论述了中国强震迁移与现代地壳波浪运动间的关系,指出了中国强震时空分布上的波浪性、方向性及丛集性特征,并将中国强震运动划分为天平式运动、单波系波浪运动、双波系波浪运动、多波系波浪运动等类型,进而对强震机制进行了探讨,指出强震波带和强震丛集区仍是今后强震活动的主要场所。  相似文献   

MULTICOMPONENT DETERMINATIONS BY A MEMBRANE-DISCRIMINATED GAS PHASE ANALYZER AND SUCCESSIVE REGRESSION IN THE FIDUCIARY REGION     

KAJPETERSEN  JORGEL.LOPEZ  PURNENDUK.DASGUPTA 《地理学报(英文版)》1989,(3)

A membrane-discriminated gas phase analyzer is proposed for multicomponent determinations. Nitrogengas flows countercurrent through outer and inner channels in a tube-in-tube arrangement. The onlycommunication between the two channels occurs through a 500μm aperture covered by a porous PTFEmembrane. A mixture of organic compounds (up to four components) is injected into the inner channelby a heated backflushed injector and the sample components diffusing into the outer channel aremonitored by a flame ionization detector (FID). A calibration set, consisting of pure components, binary,ternary and quaternary mixtures (a total of 64 samples), provides the known data base: temporal profilesof the FID output as a function of sample composition, Although the overall response behavior is nota linearly additive function of individual analyte concentrations, the use of successive inverse multiplelinear regression (while continually altering the choice of the calibration samples considered for theforward regression, on the basis of the most recent values of the predicted unknown sample composition)is shown to yield analytical results for unknown samples that are in good agreement with their true values.  相似文献   

BOOK REVIEWS     

《The Professional geographer》1986,38(3):295-316

Book Reviewed in this article: Marine Resources of Kuwait: Their Role in the Development of Non-oil Resources . Fatimah H. Y. al -Abdul -Razzak Recollections of a Revolution: Geography as Spatial Science . Mark Billinge , Derek Gregory and Ron Martin Entre l'Eden et l'Utopie . Luc Bureau Developments in Political Geography . M. A. Busteed The Elements of Graphing Data . William S. Cleveland Rural Resource Management . Paul J. Cloke and Chris C. Park Third World Atlas . Ben Crow and Alan Thomas Exploitation, Conservation, Preservation: A Geographic Perspective on Natural Resource Use . Susan L. Cutter , Hilary Lambert Renwick, and William H. Renwick . Wine Regions of the Southern Hemisphere . Harm Jan de Blij Regional Development: Problems and Policies in Eastern and Western Europe . George Demko The Geographer at Work . Peter R. Gould Change in the Amazon Basin . John Hemming Geography Since the Second World War . R. J. Johnston and P. Claval Urbanization in China: Town and Countryside in a Developing Economy 1949–2000 A.D. , R. J. R. Kirkby Transport and Communications for Pacific Microstates: Issues in Organisation and Management . Christopher C. Kissling Fluvial Forms and Processes . David Knighton The Urban Millennium . Josef W. Konvitz Technological Transition in Cartography . Mark Stephen Monmonier Field Guide to Soils and the Environment: Applications of Soil Surveys . Gerald W. Olson Northern Australia: The Arenas of Life and Ecosystems on Half a Continent . Don Parkes A Killing Rain: The Global Threat of Acid Rain . Thomas Pawlick From the Family Farm to Agribusiness: The Irrigation Crusade in California and the West, 1850–1931 . Donald J. Pisani Hybrid Maize Diffusion in Kenya . Franz -Michael Rundquist Warning and Response to the Mount St. Helens Eruption . Thomas F. Saarinen and James L. Sell Coastal Geomorphology in Australia . B. G. Thom Tropical Rain Forests of the Far East , 2nd ed . T. C. Whitmore The Dark Side of the Earth . Robert Muir Wood Categorical Data Analysis for Geographers and Environmental Scientists , Neil Wrigley  相似文献