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301.
详细讨论了卫星遥感技术在长江流域水资源管理方面的应用问题,提出了两种实用的方法:①卫星遥感技术在灌溉水资源管理方面的应用;②长江流域地下水、地表水资源估算。进一步分析了两种方法的特点,介绍了卫星遥感技术的优点及用途,建议在长江流域水资源管理中加以利用。 相似文献
302.
长江中游平原湖区农业开发地域分工与农产品专业化生产研究 总被引:5,自引:1,他引:5
农业生产地域分工与农产品专业化生产是使农业从自然经济阶段向以市场为导向的商品农产品生产转变的一个标志。本文在分析该区农业布局现状及其存在问题的基础上,提出了农业总体布局的设想与不同类型地域农业开发的主攻方向与对策,并对市场经济体制下粮食、棉花、猪、禽、水产品等农产品生产基地的地域选择、建设规模与技术措施等进行了探讨。 相似文献
303.
该模型具有长期经济协调预测、优化和模拟的功能,它将国民经济分为16个部门,充分考虑了影响国民经济各部门变化的主要因素,在供需、资金、流入流出、水资源、环境等均衡约束条件下,以 1990年不变价格,采用线性规划方法,逐年滚动优化预测了1991~2020年烟台市国民经济发展的趋势、产业结构和规模等各项指标。 相似文献
304.
中国的人口,资源,环境问题及若干战略选择 总被引:3,自引:0,他引:3
王毅 《中国人口.资源与环境》1993,3(1):50-54
中国具有十分特殊的基本国情,如何根据中国的国情以及特定的历史与现实条件,选择适宜的组织机制,实施正确的长期发展战略,加速中国的现代化进程,这是一个十分紧迫而又令人关注的重大课题。本文主要从人口、资源、环境等方面分析中国现代化所面临的困境,以及应采取的战略选择。 相似文献
305.
湖北野生食果资源特点及其开发途径 总被引:2,自引:0,他引:2
野生食果为营养丰富的食用资源植物。在深入调查的基础上,分析了湖北野生食果资源的特点,提出了野生食果资源开发的对策以及产品深加工的途径,为野生食果资源的开发利用打下了坚实的基础。 相似文献
306.
Y. Chen H. R. Jia S. Niu X. Zhang H. L. Wang Y. Z. Ye Q. S. Chen Z. L. Yuan 《Russian Journal of Ecology》2018,49(1):40-46
Species turnover patterns can be inconsistent due to differences in the dispersal ability of different growth forms. Here, species of trees, shrubs, herbs, and bryophytes in the Xiaoqinling National Nature Reserve in China were analyzed to determine patterns of species turnover along an elevation and spatial gradient. Variance partitioning was used to assess the relative contribution of topographic heterogeneity and dispersal limitation to species turnover. Our results suggest that the effect of dispersal limitation is more important than topographic heterogeneity on species turnover in temperate mountane ecosystems in the study area. Dispersal limitation has a greater effect on trees species turnover than on shrubs, herbs or bryophytes species turnover. 相似文献
307.
This paper discusses the basic concept and connotation of population modernization. The author briefly analyzes the actuality of population modernization in China, gives some advice and puts forward some measures. 相似文献
308.
Wang Xinmin Hou Yanlin & Jie Xiaolei Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China Department of Resource Environment Henan Agricultural University Zhengzhou China. 《中国人口.资源与环境(英文版)》2004,2(4)
A pot experiment was conducted to investigate the influence of citric and oxalic acids effect on Pb and Zn uptake by corn and winter wheat. The experiment was employed with citric acid (CA) applied at 3 rates (0, 1.5 and 3.0 mmol kg-1 soil), oxalic acid (OA) at 3 rates (0, 1.5 and 3.0mmol kg-1 soil) and citric acid combined with oxalic acid (1.5 mmol citric acid combined with 1.5 mmol oxalic acid kg-1). Two types of soil were chose in the experiment. One was collected from the agricultural soil near a battery-recycling factory in Anhui province, China (site A) and the other was collected from a Pb-Zn mine residues in Hunan province, China (site B). The results showed that soil pH varied with the different treatment of citric and oxalic acids. However, there were no differences in all the treatments. 3.0mmol CA kg-1 soil addition significantly increased the concentrations of the CaCI2-extractable Pb and Zn and other treatments have no significantly increased. The highest shoot concentrations of Pb and Zn 相似文献
309.
Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides 总被引:1,自引:0,他引:1
Iyengar GV Kawamura H Dang HS Parr RM Wang JW Akhter P Cho SY Natera E Miah FK Nguyen MS 《Journal of environmental radioactivity》2004,77(3):221-232
Daily dietary intakes of two naturally occurring long-lived radionuclides, 232Th and 238U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232Th and 12.7 mBq for 238U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 ug) 232Th and 23.6 mBq (1.9 ug) 238U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232Th and 15.6 mBq 238U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232Th and 238U were calculated to be 0.34 and 0.20 microSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 microSv to man from the natural radiation sources as proposed by UNSCEAR. 相似文献
310.
The growth and alkaline phosphatase activity (APA) of two raphidophyceae species Chattonella marina and Heterosigma akashiwo were investigated in response to P-limitation and subsequent addition of dissolved inorganic phosphorus (DIP, NaH2PO4) and two dissolved organic phosphorus (DOP) compounds: guanosine 5-monophosphate (GMP) and triethyl phosphate (TEP). APAlevels increased greatly after P-starvation as the decrease of the cellular phosphorus quotes (Qp). C. marina responded to P-limitation quickly and strongly, with 10-fold increase in APA within 24 hr after P-starvation. The larger difference between maximal and minimal Qp values in C. marina indicated its high capacity in P storage. APA of H. akashiwo wasmaximally enlarged about 2.5 times at 48 hr of P-starvation. After the addition of nutrients, cell numbers of C. marina increased in all treatments including the P-free culture, demonstrating the higher endurance of C. marina to P-limitation. However, those of H. akashiwo increased only in DIP and GMP cultures. APA increased only after the addition of the monophosphate ester GMP. The results suggest that quick responses of C. marina to P-limitation, high capacity in P storage as well as endurance for P-depletion provide this species an ecological advantage in phytoplankton community competition under DIP-limited conditions. 相似文献