Evolutionary model of free economic zones     

Meng Guang-wen 《中国地理科学(英文版)》2005,15(2):103-112

Free economic zone (FEZ) has a long history and plays a more and more important role in the world economy. Most studies, however, focused on the theoretical analysis of benefit and cost as well as the economic role of FEZ in the less developed countries and little attention has been paid to the evolution of FEZ. This paper will improve the above-mentioned studies and put forward the structural and spatial evolutionary model of FEZ by analyzing the development of objectives, preferential policy, governance structure, industrial sectors and location of FEZs based on the international economic and political development. FEZs develop towards: 1) more comprehensive and macro objectives, 2) more industry-oriented and multi-preferential policies, 3) more cross-national and combination zones with administrative areas, 4) more technology-intensive and multi-industries, 5) more flexible location and larger spatial dimensions, 6) more rapid evolution and typologies, and 7) more economic integration to the host economy. Biography: MENG Guang-wen (1960–), male, a native of Tianjin of China, Ph.D., specialized in regional planning and policy, environmental planning, tourist planning and management. E-mail: gwmeng98@hotmail.com  相似文献   

Seasonal variability of the Antarctic Coastal Current and its driving mechanisms in the Weddell Sea   总被引：2，自引：0，他引：2  

Ismael Núez-Riboni  Eberhard Fahrbach 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):1927-1941

Insight into the dynamics of the Antarctic Coastal Current (ACoC) is achieved by quantifying the contributions of its driving mechanisms to the seasonal variability of its barotropic and baroclinic components. These mechanisms are sought out in the local wind, the sea-ice concentration, wind curl of the Weddell Gyre (Sverdrup transport) and the thermohaline forcing related to warming/cooling and ice melting and freezing. These driving mechanisms induce most of the seasonal variability of both the barotropic and baroclinic components of the ACoC by deepening the pycnocline towards the coast and sharpening the baroclinic profile following thermal wind balance. The resulting coastal current has mainly a barotropic transport (82%) and a major annual cycle, which explains 37% of this component's variability (tides and other high-frequency events generate 40%). The wind contributes with 58% of the seasonal variability of the barotropic component and 23% of the baroclinic; the sea-ice concentration contributes with 8% and 18%, respectively; Sverdrup transport with 4% and 30% and the thermohaline forcing with 30% and 29%. The results of this study are obtained with analysis of fifteen CTD sections (potential density and geostrophic velocities) of RV-Polarstern obtained between 1992 and 2005, as well as composite, spectral and harmonic analyses of 9 years of time series from moored instruments (current speed and temperature), wind speed, atmospheric pressure and sea-ice concentration of satellite imagery.  相似文献   

自然金—银类质同象系列矿物晶胞参数变化规律及其表述方程     

姜跌先 《地球科学与环境学报》1991,(3)

本文提出了自然金—银类质同象系列矿物晶胞参数与金、银原子数百分比成二次函数关系,并推导出了表示二者之间函数关系的方程式。利用该方程式,可以用金原子数百分比计算出晶胞参数,反之亦然。并首次将其应用在自然金—银类质同象系列矿物的研究中。  相似文献   

五维波动问题的一种解法     

谭阳  柯红路 《广东海洋大学学报》2006,26(3):71-73

介绍解五维波动问题的微分算子级数法,首先引进数性算子概念及微分算子级数法;其次,推导出了求解公式;最后通过求解公式求解了一些五维波动方程的例题,得出任何维数(n≥5)的波动方程柯西问题都可以用微分算子级数法求其解。  相似文献   

Basin‐scale stream‐flow forecasting using the information of large‐scale atmospheric circulation phenomena     

Rajib Maity  D. Nagesh Kumar 《水文研究》2008,22(5):643-650

It is well recognized that the time series of hydrologic variables, such as rainfall and streamflow are significantly influenced by various large‐scale atmospheric circulation patterns. The influence of El Niño‐southern oscillation (ENSO) on hydrologic variables, through hydroclimatic teleconnection, is recognized throughout the world. Indian summer monsoon rainfall (ISMR) has been proved to be significantly influenced by ENSO. Recently, it was established that the relationship between ISMR and ENSO is modulated by the influence of atmospheric circulation patterns over the Indian Ocean region. The influences of Indian Ocean dipole (IOD) mode and equatorial Indian Ocean oscillation (EQUINOO) on ISMR have been established in recent research. Thus, for the Indian subcontinent, hydrologic time series are significantly influenced by ENSO along with EQUINOO. Though the influence of these large‐scale atmospheric circulations on large‐scale rainfall patterns was investigated, their influence on basin‐scale stream‐flow is yet to be investigated. In this paper, information of ENSO from the tropical Pacific Ocean and EQUINOO from the tropical Indian Ocean is used in terms of their corresponding indices for stream‐flow forecasting of the Mahanadi River in the state of Orissa, India. To model the complex non‐linear relationship between basin‐scale stream‐flow and such large‐scale atmospheric circulation information, artificial neural network (ANN) methodology has been opted for the present study. Efficient optimization of ANN architecture is obtained by using an evolutionary optimizer based on a genetic algorithm. This study proves that use of such large‐scale atmospheric circulation information potentially improves the performance of monthly basin‐scale stream‐flow prediction which, in turn, helps in better management of water resources. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Snow water content estimation from measured snow temperature     

李志军  赵海清  冯恩民  程斌  卢鹏 《极地研究(英文版)》2007,18(1):1-7

The vertical temperature profiles of snow and sea ice have been measured in the Arctic during the 2nd Chinese National Arctic Research Expedition in 2003(CHINARE2003).The high-resolution temperature profile in snow is solved by one-dimensional heat transfer equation.The effective heat diffusivity,internal heat sources are identified.The internal heat source refers to the penetrated solar radiation which usually warms the lower part of the snow layer in summer.By temperature gradient analysis,the zero level can be clarified quantitatively as the boundary of the dry and wet snow.According to the in situ time series of vertical temperature profile,the time series of water content in snow is obtained based on an evaluation method of snow water content associated with the snow and ice physical parameters.The relationship of snow water content and snow temperature and temporal-spatial distribution of snow water content are presented  相似文献   

利用GPS基准站数据浅析我国地壳垂直运动   总被引：1，自引：0，他引：1  

荣敏  孙付平  贾小林  周巍  刘光明 《测绘工程》2009,18(4):7-9

应用国内GPS基准站1999-2005年共？年的垂直位移时间序列数据，浅析我国的地壳垂直运动。粗略地分析GPS基准站的垂向位移分量时间序列，表明地壳垂直运动受到多种因素的影响。  相似文献   

Stream nitrate levels in a small catchment in south west England over a period of 35 years (1970–2005)     

Tim P. Burt  Fred Worrall 《水文研究》2009,23(14):2056-2068

This study considers a 35‐year record of streamwater nitrate concentration in a small agricultural catchment in south west England (Slapton Wood). The study revisits earlier work to assess whether upward trends have been maintained and how the controls upon streamwater concentration have been altered. The study has shown that (1) the catchment has reached a new position of equilibrium and increases in nitrate concentration have lessened; (2) the occurrence of severe drought in the record means that records of less than a decade are misleading and only long‐term records can illustrate changes of state; (3) the change of state observed in the catchment is illustrated in the switching of long‐term memory effects from a negative to a positive annual memory and (4) several significant long‐term impulsivity relationships with rainfall that become insignificant over the course of the study period. The study shows the importance of long‐term records in understanding changes in state in catchments and understanding the time constants of a range of driving processes. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Neural network time series prediction of environmental variables in a small upland headwater in NE Scotland     

M. J. Aitkenhead  R. J. Cooper 《水文研究》2008,22(16):3091-3101

Short‐term prediction of environmental variables such as stream flow rate is useful to members of the general public and environmental scientists alike, providing the ability to predict environmental disasters or scientifically interesting events. Here, a neural‐network based method is presented, which is capable of providing advance flood warnings or the prediction of high stream flow events for research purposes in a small upland headwater in NE Scotland. This method relies on training from past time series data acquired in the field, and provides the ability to predict a range of hydrological and meteorological variables up to 24 h ahead using feedback of predicted values at time t as new inputs for the next time step t + 1. The system is rapid and effective, relies on standard neural network training methods, and has the potential to be implemented in a web‐based monitoring and prediction package. The model design could be implemented at any study site where time series data has been gathered, and is sufficiently flexible to accept whatever data is available. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

黔北牛蹄塘组的地球化学特征及形成环境   总被引：7，自引：5，他引：7  

袁宏  肖加飞  何熙琦  白平 《贵州地质》2007,24(1):55-59,63

贵州北部早寒武世的黑色岩系-牛蹄塘组。主要为黑色页岩,含浮游生物,其中产钼、钒等矿床。其具有独特的元素地球化学特征:K、Ti元素在黑色页岩中的含量高于底部硅质岩,而P元素的含量却相反,硅质岩中的含量显著高于其上覆的黑色页岩;岩孔和菜园两地的共同特点是V、Ba、U的含量明显偏高,富集系数在3以上,显著的差别是Ta元素,其在岩孔是亏损的,而在菜园却明显富集;西部岩孔的稀土总量高于东部菜园,稀土配分曲线形态近于水平或略向左倾,具弱的负Eu异常或不显异常。硅质岩较页岩的负Ce异常程度高。地层特征、元素地球化学特征及特征元素和比值,所反映的是下寒武统牛蹄塘组形成于缺氧的还原环境。  相似文献