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1.
林芝生态环境非常脆弱,经济发展相对落后,从可持续发展角度研究其人口问题具有重要的现实意义。本文采取静态分析与动态分析相结合的方法,以区域经济可持续发展和人口发展理论为基础,分析了林芝区域经济与人口发展现状及存在的问题,提出了通过控制人口规模,努力提高农村劳动力素质,积极推进农村城镇化,大力发展乡镇企业和县城经济等,促进林芝地区区域可持续发展的政策和措施。  相似文献   

2.
首先对国内外水资源承载能力的定义进行了归纳,并提出了一个水资源承载能力的新的定义;在此基础上,介绍了水资源承载力的三种度量指标,即水量指标、人口指标和社会综合类指标;分析了国内外水资源承载能力的综合评价指标体系,并对水资源承载能力计算的定性与定量分析方法进行了评述.对水资源承载能力研究中的有关问题提出了建议.  相似文献   

3.
从科学技术的角度,运用魏建中区域经济可持续发展多目标综合评价模型,将山西省资源环境承载能力与经济增长方式放在一个体系下进行了定量分析和研究,并根据所得指标对山西省的资源、环境承载力与经济增长方式进行了评价和预测。  相似文献   

4.
为了评价区域可持续发展程度,构建了涉及人口、经济、社会、资源、环境5个子系统71个指标的区域可持续发展指标体系。提出了运用改进的主成分分析法计算各子系统的可持续发展水平值,采用回归分析法确立可持续发展协调模型,利用正、负加权海明距离公式对区域的可持续发展综合指数进行计算。用上述方法对大连市区域可持续发展水平进行了综合评价。  相似文献   

5.
根据生态足迹理论和方法,对河南省2004年的生态足迹进行了计算.结果表明,河南省区域发展处于不可持续状态,社会发展与资源供给间矛盾突出.要改变这种状况,必须在健全政策体系、控制人口规模、加强资源保护和利用等方面积极采取措施,这样才能提高区域可持续发展能力.  相似文献   

6.
文章在论述区域水资源可持续利用与水资源承载能力关系的前提下,提出了区域水资源可持续利用评价的模糊模式识别理论、模型和方法。应用所建立的模型对汉中盆地水资源可持续利用的程度进行了评价,应用实例表明,理论模型严谨,方法简洁,评价结果合理可行。此方法也可用于区域社会经济可持续发展等的评价。  相似文献   

7.
基于围岩破坏区和承载力的锚杆支护设计   总被引:2,自引:0,他引:2  
从岩石力学最大周向拉应力破坏准则理论出发,结合隧道工程实例,运用理论分析和现场试验数据统计分析的方法,研究了隧道开挖过程中破坏区域的范围和破坏规律,并对破坏区域的承载能力进行了分析。结果表明:隧道开挖过程中围岩破坏区域承载了很大的荷载,而支护体系承受的荷载只是很小一部分;围岩破坏范围和破坏区域的承载能力可以通过岩体的力学参数进行计算得出。工程应用表明,锚杆支护设计参数可以通过计算围岩的破坏区域和承载能力获得。  相似文献   

8.
分析了四川藏族聚居人口在区内各自然地理区域的分布格局,并用人口地理学和人类生态学的理论,探讨了该区土地资源对人口的承载能力,估算出该区的适度人口容量约为165万,进而论证了在四川藏区控制人口增长的必要性.  相似文献   

9.
人口容量是近年来地理学和人口学研究的热点问题。传统的研究方法往往把人口容量支持系统局限于关闭区域不可移动的自然资源,如耕地等,忽视与外界的物能交换,而这种交换在现代开放经济条件下对区域人口容量是至关重要的。本文以人多地少、物能交换频繁的沪苏锡常城市连绵区为例,考察了开放条件下区际补给对耕地资源人口容量的影响,并就有关的问题进行了理论上的分析,以有助于人口容量理论的研究和发展。  相似文献   

10.
西部大开发以来内蒙古可持续发展系统评价研究   总被引:1,自引:0,他引:1  
基于区域人口、资源、环境与经济系统的协调发展的层面,探讨了内蒙古可持续系统协调发展问题.在对内蒙古可持续发展系统要素构成及西部开发以来内蒙古可持续发展系统状态进行分析的基础上,建立内蒙古可持续发展系统评价指标体系,采用相对比较成熟的主成分分析与回归分析相结合的综合评价方法来分析西部大开发以来内蒙古可持续发展水平及协调发...  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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