Urban three-dimensional expansion and its driving forces —A case study of Shanghai, China   总被引：4，自引：1，他引：3  

Longyu Shi  Guofan Shao  Shenghui Cui  Xuanqi Li  Tao Lin  Kai Yin  Jingzhu Zhao 《中国地理科学(英文版)》2009,19(4):291-298

Urban expansion is a phenomenon of urban space increase, and an important measuring index of the process of urbanization. Taking Shanghai as an example, the changes of urban average height and built-up area were studied to represent city’s vertical and horizontal increases respectively, and statistical methods were used to analyze the driving forces of urban expansion. The research drew following conclusions: 1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature, and could be divided into three stages: vertical expansion in dominance, coordinated vertical and horizontal expansion, and horizontal expansion in dominance. 2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs, but the changing speed of the latter was faster. And 3) urbanization process was the major driving force for the city’s horizontal expansion, while industrial structure improvement was the key driving factor for the vertical expansion. Those two driving forces were simultaneously affected by city’s political factors.  相似文献   

方斑东风螺不同批次卵质量的比较     

黄海立  梁飞龙  符韶  刘定 《广东海洋大学学报》2006,26(4):31-34

2005年5月~8月在雷州市覃斗镇海威水产种苗基地的室内水池进行方斑东风螺亲螺培育,对亲螺不同批次产出的卵囊、卵、及其幼虫进行比较。结果表明:随着亲螺产卵批次的增加,亲螺产卵囊数、卵囊含卵数、产卵量逐次减少;卵囊长、宽逐次变小,厚逐次增加,形状由葵花子片状的比例大变为棒状的比例大;幼虫浮游期逐次延长;变态期幼虫壳长逐次变小;各批次之间的变态率逐次降低;卵径、孵化率、出囊幼虫大小差异不显著。  相似文献   

方斑东风螺两种养殖模式的比较     

黄海立  周银环符韶  梁飞龙刘定 《广东海洋大学学报》2006,26(3):8-12

在室内水泥池，利用沙层自净养殖模式和直接铺沙养殖模式对不同规格的方斑东风螺（Babylonia areolata Link）进行了高密度养殖的研究。结果表明，沙层自净养殖模式养殖小螺、中螺、大螺组日均增重分别为0．031、0．088、0．098g／d，沙层NH4^＋-N最高含量ω分别为1．3、2．1、3．1mg,／L,H2S最高含量ω分别为0．03、0．07、0．14mg／L．各规格组东风螺保持正常生长和活动，成活率92．9％以上；直接铺沙养殖模式养殖小螺、中螺、大螺日均增重分别为：0．023、0．051、0．068g／d．成活率分别为95．2％、86．7％、84．9％，沙层NH4^＋-N最高含量ω达到13．7mg／L，H2S最高含量ω达到0．47mg／L，沙层底质恶化，东风螺活动异常、不摄食。可见，沙层自净养殖模式对方斑东风螺的生长、成活率、沙层水质控制效果显著，在一定程度上克服了直接铺沙养殖底质恶化问题。  相似文献   

Modelling of anisotropic damage in brittle rocks under compression dominated stresses     

Y.F. Lu  J.F. Shao 《国际地质力学数值与分析法杂志》2002,26(10):945-961

A new model for describing induced anisotropic damage in brittle rocks is proposed. Although phenomenological, the model is based on physical grounds of micromechanical analysis. Induced damage is represented by a second rank tensor, which is related to the density and orientation of microcracks. Damage evolution is related to the propagation condition of microcracks. The onset of microcrack coalescence leading to softening behaviour is also considered. The effective elastic compliance of the damaged material is obtained from a specific form of Gibbs potential. Irreversible damage‐related strains due to residual opening of microcracks after unloading are also captured. All the model's parameters could be determined from conventional triaxial compression tests. The proposed model is applied to a typical brittle rock. Comparison between test data and numerical simulations shows an overall good agreement. The proposed model is able to describe the main features related to induced microcracks in brittle geomaterials. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

环境植物样品中铜铅锌铁锰的测定     

马欣  丛玉梅  邵文君 《国土资源》1995,(1)

将环境植物样品在４００─５００℃灰化，用硝酸、氢氟酸和高氯酸分解，用盐酸（１＋１）提取，控制２％─３％的盐酸介质，用火焰原子吸收分光光度法测定环境植物样品中的微量铜、铅、锌、铁、锰。该方法简单、快速、可靠。对环境植物标准样品的测定结果理想。  相似文献   

Integrated Indicators-based Gradation of Cultivated Land Quality in Mountainous Region of Southwestern China   总被引：1，自引：0，他引：1  

SHAO Jing＇an WEI Chaofu XIE Deti ZHOU Yan 《山地科学学报》2006,3(3):259-270

1 Introduction The gradation of cultivated land is to assess the suitability of cultivated land for agricultural production in terms of natural and economic prop-erties of land (Feng et al. 2004). It can be used to evaluate sustainability of land use and …  相似文献   

AN INSIGHT ON DRIVERS OF LAND USE CHANGE AT REGIONAL SCALE   总被引：2，自引：0，他引：2  

SHAO Jing-an WEI Chao-fu XIE De-ti 《中国地理科学(英文版)》2006,16(2):176-182

1INTRODUCTION Land use change (LUC) involves both changes to a dif- ferent function and shifts in intensity within a function. Today, researches on LUC are aiming at regional scale, andthestudiesofthetypicalregionalLUC drivingforces at meso- and small-scale become a key issue (VAN DIGGELEN et al., 2005; CHAPLOT et al., 2005). The studies of regional LUC driving forces are to reveal the realmotivationbehindtheLUCanditsinteractingmech- anism, so as to simulate and predict the p…  相似文献   

我国海水养殖珍珠业存在的问题及对策   总被引：6，自引：0，他引：6  

邓陈茂  黄海立符韶 《广东海洋大学学报》2006,26(5):5-9

在详细分析我国海水珍珠养殖业存在问题的基础上，提出了统一规划海区，定量、低密度和开展外海深水海区珍珠养殖；加速大型珍珠贝全人工养殖与育珠的研究，丰富养殖品种；建立良种场、实行马氏珠母贝种质复壮；加强技术推广，延长育珠期、提高珍珠质量；抓好珍珠深加工、开拓珍珠产业链；建立龙头企业，带动珍珠业向集约型发展等可持续发展对策。  相似文献   

A standard format for reporting PILPS experiments     

Jan Polcher  Yaping Shao 《Global and Planetary Change》1996,13(1-4)

In model inter-comparisons one major obstacle is the format of the reported data. To facilitate the analysis of the results from the different models they should all be reported in the same format. This requires that the format is flexible enough to be easily implemented into the different land surface schemes. It should also be fault tolerant and allow a few consistence checks to avoid erroneous data to be submitted. The present note describes such a format developed for the PILPS project. After discussing the aim of this new format we present the routines which are used to write and read data. Finally two applications are described which allow the user to perform a number of consistency checks on the data.  相似文献   

成团天体系统成员概率计算的有效性问题     

邵正义  赵君亮 《天文学报》1996,37(4):377-386

本文提出了一个普适的衡量成团天体系统成员概率计算结果的有效性指数：Ｅ＝１－ＮΣ｛Ｐ（ｉ）［１－Ｐ（ｉ）］｝／ΣＰ（ｉ）Σ［１－Ｐ（ｉ）］｝，并以此对以Ｓａｎｄｅｒｓ方法为基础的各种成员确定模型的有效性进行了分析．从总体上说，运动学资料（自行、视向速度等）是一类有效的观测判据．  相似文献