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91.
92.
随着濮阳市城市框架的不断拉大,建设用地需求不断增加,在国家紧缩"地根"的形势下,做好节约集约用地工作尤为重要。今后各项建设要优先开发利用空闲、废弃、闲置和低效利用的土地,努力提高建设用地利用效率,严格执行闲置土地处置政策。重点在盘活城镇存量上下工夫,提高土地利用效益。 相似文献
93.
Heikkila E 《Terra (Helsinki, Finland)》1994,106(4):374-383
"Population ageing has emerged as one of the crucial problems facing developed countries. In Finland, the old population (aged 65 and over) has doubled in numbers over the past 30 years. The phenomena underlying this ageing trend include a decline in fertility, increase of the average life expectancy, and the effects of migration. Considerable regional differences in population ageing can be observed between Finland's provinces, municipalities and between their different parts. The number of the elderly is projected to increase in all provinces, the highest relative increase taking place in the provinces of Lapland, Uusimaa and Oulu between 1990-2020." (SUMMARY IN ENG) 相似文献
94.
含煤层地质环境下地震波场的数值模拟 总被引:3,自引:2,他引:1
本文对含低速煤层地质环境下弹性波场多波多分量地震资料进行了二维数值模拟研究,对人工边界反射进行了有效处理,频散效应得到了有效的压制,对几种不同激发与观测排列方式下的弹性波资料进行了模型计算与分析。 相似文献
95.
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Ngwa Nebasina E 《GeoJournal》1995,35(4):515-520
Rural Cameroonian women interact with the environment through their numerous daily chores, and so produce in each Cameroonian ecological zone specific problems which with time can no longer be managed. In cutting down and burning the vegetation so as to create farms, in fetching water, fuel wood and so on in order to satisfy the needs of each household, the Cameroonian rural woman is pushed into a situation where she devastates and accelerates environmental degradation.In any ecological, climatic, ethnic or cultural zone, in which she finds herself, she sets in motion the continuous natural resource consumption process. Unfortunately, she has no firm authority over the land, credit and decision-making where she can come in, interact and check some of these negative consequences. The men have also been identified as accomplices in this environmental degradation process since they push the women into taking much from the environment so as to satisfy men and general domestic needs.Since the rural Cameroonian women constitute a potential partner (56,6%) of the rural production force, this paper highlights the problems created in each zone with the view of awakening public opinion, and creating an awareness of the magnitude in each zone. Some proposals, through the discussion methodology are envisaged. This, through compensatory measures, exchanges in take and give, and in farm community actions to uphold any positive checks. When all these are properly focused and the women's right to land, credit, training and decision-making recognised, they can be brought to the forefront as partners in the better management of the environment. 相似文献
97.
Interstellar water in meteorites? 总被引:1,自引:0,他引:1
D/H ratios of two meteorites (Renazzo CR and Semarkona LL3), which are known to exhibit the largest departures from the terrestrial hydrogen isotopic ratios, have been determined with the CRPG Nancy ion microprobe. Correlations between the D/H ratios and the chemical compositions (H2O, K, Si, C/H) of plausible hydrogen carriers were observed. From these correlations, it is possible to show that, contrary to previous interpretations, phyllosilicates are the carriers of the deuterium-rich hydrogen in Semarkona and Renazzo: 870 x 10(-6) > or = D/H > or = 670 x 10(-6) (+4600 > or = deltaD > or = 3300%) and > or = 320 x 10(-6) (deltaD > or = 1050%), respectively. Hydrogen is also present in the chondrules of these two deuterium-rich meteorites. The large differences in D/H ratios between matrix (up to 700 x 10(-6), deltaD up to +3500%) and chondrules (from 120 x 10(-6) (deltaD = -230%) to 230 x 10(-6) (deltaD = +475%)) show that hydrogen in chondrules cannot originate from the matrix by simple contamination or diffusion processes. The high D/H ratios measured in water-bearing minerals could not have been produced thermally within a dense solar nebula. Chemical reactions (i.e., involving ions or radicals), taking place in interstellar space or in the outer regions of the nebula at 110-140K are presently the only conceivable mechanisms capable of yielding such isotopic enrichments. Water in these meteorites should no longer be considered as a simple product of nebular condensation under equilibrium thermodynamic conditions at T > or = 160K. 相似文献
98.
"Debates concerning the origins and development of the late nineteenth- to early twentieth-century declines in marital fertility and infant mortality in England and Wales have been centred largely on the material provided by answers to the ?special' questions in the 1911 census. In their published form these figures have restricted researchers to an examination of large scale geographic and social class differences in the levels and rates of decline of the two phenomena. This paper outlines research conducted on a sample of individual census returns from the 1911 census. From this data it becomes clear that for Victorian and Edwardian England ?where one lived' was rather more important than ?who one was' in determining both family building strategies and the survival of those children born." 相似文献
99.
100.