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1.
马莉 《河南科学》2018,(1):124-128
以陕西省为例,在统计分析2001—2015年人均耕地面积、粮食产量与人口数量现状的基础上,采用灰色系统模型GM(1,1),对土地资源人口承载力进行了预测与分析.结果显示,2001—2015年间陕西省人口数量不断增长的同时人均耕地面积持续下降,土地资源压力增大.经预测,2018—2030年陕西省土地资源人口承载力呈持续超载状态,到2030年陕西省人口数量达4044万人,粮食产量为1.5万t,超载人口数量为714万人.然而,超载人口数量逐年下降,可承载的人口越来越多,土地资源的人口承载能力在不断提升.因此,在今后的社会经济发展过程中仍需要合理地控制人口增长,提高土地生产潜力,缓解因超载人口所带来的土地资源压力.  相似文献   

2.
以传统的反映人粮关系的食物型人口承载力及反映土地资源经济产出的货币型人口承载力来综合确定土地资源人口综合承载力,运用系统动力学模型的原理和方法模拟仿真山东省未来十几年不同情景下的土地资源人口承载力变化,建立了区域土地资源人口承载力模型,得出较优的发展方案.结果表明:到2020年,食物型-温饱型土地资源人口承载力为18 634.6万人,货币型-生存型土地资源人口承载力为21 596.4万人,综合享受型土地资源人口承载力为20 500.5万人.  相似文献   

3.
提出水库库周区土地极限人口承载力分析方法,即从确保水库库周区恢复自我发展能力的角度出发,结合水库库周区的特点,依据库周区自然资源状况、社会经济发展水平及长期发展战略,以人均纯收入为土地极限承载力预测分析主要定量分析指标,采用一元线性回归法、时间序列趋势外推法、频率曲线、3次样条插值法对投入产出、收入目标和人口增长进行综合预测,建立数学模型,计算土地生产潜力.以沅陵县五强溪库区为例,分析2011水平年各村土地极限人口承载力.  相似文献   

4.
本文以河北省邯郸地区为例,探讨了暖温带大陆性季风条件下,灌溉农业与旱作农业并存地区土地资源人口承载潜力研究的方法。该方法在对研究区域内的土地质量、水资源、投入水平、灾害与收获损失、水土保持等多种限制因素进行分析、评价的基础上,对具体作物分光温生产潜力、光温水生产潜力、扣除灾害及收获损失后的光温水生产潜力、土地生产潜力共四个层次进行潜力计算。进而在潜力总产计算的基础上,分析消费现状,制定切合区域实际的消费指标,估算未来土地的承载力。最后就挖掘生产潜力和提高土地资源的人口承载力,保护生态环境,提出了建议。  相似文献   

5.
本文以广安县土地类型及土地合理利用方向为基础,定量地研究了各类土地的生产潜力,并依据人均食物消费水平较为客观地指出了广安县的土地人口承载力.  相似文献   

6.
土地资源人口承载力动力学模拟和应用   总被引:15,自引:0,他引:15  
人口和土地资源的关系是一种复杂的非线性关系.本文通过建立土地资源人口承载力动力学模型,运用非线性科学理论,讨论了人口-土地资源系统的演化方向和平衡态稳定性问题.稳定的平衡态是系统发展可能达到的最终状态,在人口与土地资源自治系统中,土地资源的数量和质量、人口数量和生活消费水平之间相互联系、相互制约.研究表明:(1)稳定平衡态时人口数量与土地资源生产潜力总量成正比;(2)人口数量和土地资源生产潜力总量与人类消费水平成反比;(3)人口数量和土地资源生产力与耕地面积和土地单产潜力成正比.文章对我国的土地人口承载力进行了实证分析.结果显示,我国完全有能力养活自己.  相似文献   

7.
贵州花江喀斯特峰丛峡谷耕地承载力研究   总被引:7,自引:0,他引:7  
喀斯特峰丛峡谷地区土地贫脊 ,土地有效利用面积比例小 ,土地资源生产潜力小 ,环境容量低 ,生态环境脆弱。文章从光合潜力、光温潜力、气候潜力和气候土地潜力等方面综合考虑建立土地生产潜力模型 ,对贵州花江喀斯特峰丛峡谷土地承载力的耕地承载力部分进行了估算研究。研究表明 ,仅从耕地承载力来看 ,该区目前的总人口数已经超过了该区的耕地承载力  相似文献   

8.
人口数据是进行土地利用总体规划修编的重要基础数据.采用平均增长法、线性回归法和灰色预测法对广西壮族自治区荔浦县人口规模和人口城乡结构进行预测,采用各方法的加权平均值作为最终的预测结果.荔浦县2010年预计人口规模将达到37.6万人,其中:城镇人口5.5万人,农村人口32.1万人;2020年,荔浦县总人口规模将达38.9万人,其中城镇人口5.9万人,农村人口33万人.对人口基数较少的区域进行人口预测,方法对预测结果影响不大.  相似文献   

9.
基于人粮关系的信阳市耕地资源人口承载力研究   总被引:1,自引:0,他引:1  
基于信阳市2004-2017年间耕地、人口、粮食产量等数据,运用土地资源承载力(LCC)及GM(1,1)灰色系统预测模型方法对信阳市耕地资源人口承载力进行统计预测分析.结果表明:(1)近十几年信阳市耕地资源承载力指数为0.704~0.987,总体处于粮食盈余状态.(2)信阳市在2020年、2025年和2030年三个预测年阶段的耕地资源人口承载力指数为0.739~0.744,总体处于粮食富裕状态.从人粮关系角度研究耕地资源的人口承载力状况,对保障粮食安全和区域可持续发展具有重要意义.  相似文献   

10.
该文从人口数量发展及人口消费结构、土地生产力现状及生产潜力、建设事业发展趋势等单项预测着手,运用社会需求结构与土地需求结构的综合平衡关系,建立了以综合考虑社会效益、经济效益和生态效益的多目标规划为主体的土地需求结构预测数学模型,预测了新建县2000年至2020年的土地需求结构。  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.
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   

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 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   

15.
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   

16.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

17.
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   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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