福建省基于闽台互动的产业与空间结构调整研究   总被引：10，自引：1，他引：9  

陈修颖  顾朝林 《地理科学》2003,23(4):414-421

在经济转型条件下,福建省产业和空间结构调整的依据需建立在三个层面上:一是从全球产业大转型中寻求机遇,确立自身发展的整体战略;二是从台海关系这一地缘政治、经济格局的新变局中寻求新的经济增长点并以此为依据重构空间结构;三是从地方空间层面寻求自身的优势,在协调好区域间分工关系的前提下,寻求省域产业和空间结构与上述两个层次的有机耦合。在这三个层面上,台海关系是控制产业与空间结构调整的核心。台海关系加速朝良性发展的新形势以及福建省的独特区位优势决定了福建的产业和空间结构调整必须建立在闽台互动基础之上。高效农业、电子、汽车和石化等重点产业的选择和流动空间—承转空间—地方空间—辐射空间等有机秩序空间系统的建立可以促进闽台产业、空间互动,并最终实现闽台一体化、构建台海经济区的国家战略目标。  相似文献   

泥石流危险性评价的新思路   总被引：11，自引：3，他引：8  

柳金峰  欧国强 《地质灾害与环境保护》2004,15(1):5-8

泥石流的多样性、复杂性和多因素等特征,使其具有很大的破坏性,也增加了其危险性评价的难度。近10年来,我国泥石流每年造成损失约33～36亿元,死亡数百人。由此可见,泥石流的危险性评价在我国国民经济建设中起着非常重要的作用。国内外许多学者对此也做了深入的研究,提出了许多有效的预测措施,在一定程度上减少了国家的经济损失。针对目前的研究现状,笔者系统分析和总结了当今泥石流危险性评价的研究方法,结合未来灾害学的发展方向,提出了一种基于信息熵理论研究的新思路,并进行了初步探索。  相似文献   

Nocturnal basin low-level jets: an integrated study   总被引：1，自引：0，他引：1  

Joan Cuxart 《Acta Geophysica》2008,56(1):100-113

Low-level jets (LLJs) are a very common feature in the nocturnal stably stratified boundary layer. Many factors can intervene in their generation, linked basically to effects of baroclinity. A special kind of low-level jets is composed by the nocturnal katabatic and basin flows, generated over terrain slopes. A study of observed LLJs in the Duero Basin is shown here, combining observational data and modelling experiments. Normalized in respect to the maximum wind height, the dynamic characteristics of the jets are similar: a two-layer system, with a stably stratified layer below the jet maximum and a near neutral layer above, with a very stable layer separating them at the level of the wind maximum. There is vertical mixing above and below the jet, and the connection between these layers takes place occasionally in a very turbulent manner.  相似文献   

In situ cosmogenic Be in olivines and pyroxenes     

P.-H. Blard  D. Bourls  R. Pik  J. Lav 《Quaternary Geochronology》2008,3(3):196-205

This study proposes an efficient new cleaning procedure for measuring in situ cosmogenic ¹⁰Be in olivines and pyroxenes. This chemical routine is specially designed to decontaminate the abundant meteoric ¹⁰Be from these minerals. The method was tested on mafic minerals from basaltic flows of Mt. Etna volcano and from Hawaiian flows and moraines. A sequential dissolution test shows that ¹⁰Be concentrations decrease with the number of cleaning steps until reaching a constant value. This is a necessary condition to demonstrate the efficiency of the method in properly decontaminating samples of meteoric ¹⁰Be. Moreover, cross-calibration with cosmogenic ³He measured within the same samples yielded a sea level high-latitude production rate of 4.5±0.4 at g⁻¹ a⁻¹ for cosmogenic ¹⁰Be in mafic minerals. This rate is within 1σ uncertainty of empirically or model-derived rates for ¹⁰Be on the same targets. Such concordance supports the consistency of the new method.  相似文献   

河流健康及其指标   总被引：1，自引：0，他引：1  

刘昌明  刘晓燕 《地理学报(英文版)》2009,19(1):3-11

Based on the author’s practice in river harnessing, this paper defines that a healthy river is a river whose social and natural functions can be balanced or compromised in terms of the socio-economic, ecological and environmental values associated with the river. The environmental values of river systems should be judged according to the following criteria: the signal of a healthy river should be associated with favorable riverbed, acceptable water quality, sustainable river ecosystem and compatible runoff. The river health criterion should reflect the river’s natural function status which includes the riverbed, water quality, river ecosystem and runoff. But, the variety and quantity would be different for different rivers depending on different natural features and social background. The standards to be adopted for a healthy river should be determined according to the requirements for maintaining river’s normal natural functions and the extent whether the social and natural functions could perform in a balanced way, and also the standards adopted should be adjusted according to the change of the given conditions. The key factor of river health is the enough and clean flow. The authors stressed that human activities would hurt the river health which include excessive water diversion and excessive power generation from the river, improper regulation of flood and sediment, and over discharge of sewage into the river and over change in fish habitat. Taking the Yellow River as a case, this paper also discussed the method to identify what are the standards of a healthy river as well as environmental flows. Foundation: Chinese National Research Program, No.2006BAB06B; National Key Basic Research Development Program of China “973”, No.G1999043601 Author: Liu Changming, Academician  相似文献   

Molecular hydrogen emission in Cygnus A     

R. J. Wilman  A. C. Edge  R. M. Johnstone  C. S. Crawford  A. C. Fabian 《Monthly notices of the Royal Astronomical Society》2000,318(4):1232-1240

We present J , H and K -band spectroscopy of Cygnus A, spanning 1.0–2.4 μm in the rest-frame and hence several rovibrational H₂, H recombination and [Fe  ii ] emission lines. The lines are spatially extended by up to 6 kpc from the nucleus, but their distinct kinematics indicate that the three groups (H, H₂ and [Fe  ii ]) are not wholly produced in the same gas. The broadest line, [Fe  ii ] λ 1.644, exhibits a non-Gaussian profile with a broad base (FWHM≃1040 km s⁻¹), perhaps because of the interaction with the radio source. Extinctions to the line-emitting regions substantially exceed earlier measurements based on optical H recombination lines.
Hard X-rays from the quasar nucleus are likely to dominate the excitation of the H₂ emission. The results of Maloney, Hollenbach & Tielens are thus used to infer the total mass of gas in H₂ v=1–0 S(1)-emitting clouds as a function of radius, for gas densities of 10³ and 10⁵ cm⁻³, and stopping column densities N _H=10²²–10²⁴ cm⁻². Assuming azimuthal symmetry, at least 2.3×10⁸ M_⊙ of such material is present within 5 kpc of the nucleus, if the line-emitting clouds see an unobscured quasar spectrum. Alternatively, if the bulk of the X-ray absorption to the nucleus inferred by Ueno et al. actually arises in a circumnuclear torus, the implied gas mass rises to ∼10¹⁰ M_⊙. The latter plausibly accounts for 10⁹ yr of mass deposition from the cluster cooling flow, for which within this radius.  相似文献   

Chandra imaging of the complex X-ray core of the Perseus cluster     

A. C. Fabian  J. S. Sanders  S. Ettori  G. B. Taylor  S. W. Allen  C. S. Crawford  K. Iwasawa  R. M. Johnstone  P. M. Ogle 《Monthly notices of the Royal Astronomical Society》2000,318(4):L65-L68

We report subarcsec-resolution X-ray imaging of the core of the Perseus cluster around the galaxy NGC 1275 with the Chandra X-ray Observatory . The ROSAT -discovered holes associated with the radio lobes have X-ray bright rims which are cooler than the surrounding gas and not a result of shocks. The holes themselves may contain some hotter gas. We map strong photoelectric absorption across the northern lobe and rim owing to a small infalling irregular galaxy, known as the high-velocity system. Two outer holes, one of which was previously known, are identified with recently found spurs of low-frequency radio emission. The spiral appearance of the X-ray cooler gas and the outer optical parts of NGC 1275 may be due to angular momentum in the cooling flow.  相似文献   

Non-gravitational heating in the hierarchical formation of X-ray clusters     

K. K. S. Wu  A. C. Fabian  P. E. J. Nulsen 《Monthly notices of the Royal Astronomical Society》2000,318(3):889-912

  相似文献   

Geomorphic evidence of ancient catastrophic flow type landslides in the mid-mountain ridges of the Western Flysch Carpathian Mountains （Czech Republic）   总被引：6，自引：0，他引：6  

T. PNEK  J. HRADECKY  K. ILHN 《国际泥沙研究》2009,24(1):88-98

Ancient flow type landslides are relatively frequent fossil forms of the relief in mid-mountain conditions of the Czech Carpathian Mountains. Sixty rather distinctive displays of debris flows, rock avalanches, and debris avalanches have been mapped in the uppermost part of the territory. Unlike contemporary sporadic and low volume debris flows, ancient （Pleistocene and Lower Holocene） accumulations are a few orders of magnitude more extensive and were of considerable geomorphologic significance in forming the steep sections of mountain valleys and slopes. This geomorphic pattern does not hold for flow type slides, the source of which is material released as a consequence of numerous deep-seated landslides. Due to deep disruption of slopes, a few high-magnitude flow type landslides （e.g., rock avalanches）, quite rare in flysch mid-mountain conditions, also occurred in the Late Holocene.  相似文献   

Analytical findings for power law cross-sections: Uniform flow depth     

A. Valiani  V. Caleffi   《Advances in water resources》2009,32(9):1404-1412

Analytical results concerning open channel flows are presented, assuming that the cross-section is defined by a power law relationship between the channel width and the channel depth. Explicit equations to compute the normal flow depth are derived by considering the liquid discharge, the channel roughness height and the cross-section geometry (based on knowledge of the power law exponent, the reference width, and the reference depth) as known quantities.Such equations are deduced by writing the physical quantities as a power expansion in the power law exponent and expressing the wetted perimeter using a Gauss hypergeometric function. With the designed procedure, an accurate estimations of the integrals required to invert the uniform flow formula are obtained, at least for cross-sections characterized by aspect ratios of technical interest.Two relationships are proposed between the normal depth and the flow discharge. The first relationship is shown to work well for any discharge, provided that the width to depth ratio is sufficiently large. If this is not the case, the second procedure must be used for non-dimensional discharge larger than a given threshold, while the former procedure remains valid under the threshold.  相似文献