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排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
Zhu Rong Wang Shixin Srinivasakannan C. Li Shiwei Yin Shaohua Zhang Libo Jiang Xiaobin Zhou Guoli Zhang Ning 《Environmental Chemistry Letters》2023,21(3):1611-1626
Environmental Chemistry Letters - The demand for lithium is growing rapidly with the increase in electric vehicles, batteries and electronic equipments. Lithium can be extracted from brines, yet... 相似文献
2.
张似松 《长江流域资源与环境》1993,2(2):155-159
分析江汉平原粮食生产的优势与问题,运用商品经济的观念,提出改革开放新形势下加快江汉平原粮食开发的设想,即依托市场,按照价值规律,科学地调整种植业比例和粮食种类结构,发展优质品种,扩大优化模式及采用高新技术等,通过优质、高产、高效,促进江汉平原粮食生产的发展。 相似文献
3.
Zhang Jing Feng Zhiming Yang Yanzhao 《中国人口.资源与环境(英文版)》2006,4(2):33-40
The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland" water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention, the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that ①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation. ②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level. ③Irrigation water could meet the crop water demand on Ningxia Plain in 2000, but there was not much space to expand irrigating cultivated land. 相似文献
4.
Lei Jun & Zhang Xiaolei Xinjiang Institute of Ecology Geography Chinese Academy of Sciences Urumqi China Institute of Geography Science Natural Resources Research Chinese Academy of Sciences Beijing .China 《中国人口.资源与环境(英文版)》2005,3(3)
As a special basic economic region in China, Xinjiang is situated in the arid area in the Northwest China. Oasis agriculture is the basis of the national economy. The development of oasis agriculture helps to accelerate the development of economy, social and environment. After 50 years of practice, from 1949 to 2002, oasis agriculture in Xinjiang enhanced rapidly the scale of agricultural industry and had great changes in its structure. The amount of cultivated area rose from 120.97*102 ha t… 相似文献
5.
关中地区飑线天气的预测及灾害对策探讨 总被引:1,自引:0,他引:1
对1961~1990年发生在陕西省关中地区的飑线天气及其灾害进行了统计分析,并从天气形势背景方面对飑线的发生发展进行了研究和分析,同时就飑线的预测和防灾对策进行了探讨。 相似文献
6.
In the past 20 years a variety of indices have been suggested for measuring the severity of trauma, however none of them meets the requirement of being a simple and objective instrument that can be utilized efficiently by lay persons and providers of health services without previous experience in triaging. A new system has been proposed which meets this requirement and which has been validated with 197 injured persons at the emergency ward of the Valle University Hospital in Call, Colombia. The instrument showed a high level of concordance with the conventional triaging method and classifies victims into four categories: critical with recovery unlikely, critical but recoverable, moderately serious, and ambulatory. There is discussion on the reliability of this instrument and it is recommended that it be validated with victims from larger disasters. Regardless, it has the advantage of being specific and free of the subjectivity that characterizes other indices. 相似文献
7.
Inorganic nitrogen metabolism in blue light was studied for the green algaUlva rigida C. Agardh collected in the south of Spain (Punta Carnero, Algeciras) in the winter of 1987. NH4
+ has been reported to inhibit NO3
- uptake; however,U. rigida showed a net NO3
- uptake even when the NH4
+ concentration of the external medium was three or four times greater than the concentration of NO3
-. NO3
- uptake rates were similar in both darkness and in blue light of various photon fluence rates (PFR) ranging from 17 to 160 mol m-2 s-1. Since NO3
- uptake is an active mechanism involving the consumption of ATP, respiratory metabolism can provide enough ATP to maintain the energetic requirement of NO3
- transport even in darkness. In contrast, NO3
- reduction inU. rigida was highly dependent on the net photosynthetic rate. After 7 h in blue light, intracellular NO3
- concentrations ([NO3
-]
i
) were higher in specimens exposed to intensities below the light compensation point (LCP) than in those incubated at a PFR above the LCP. When PFR is below the light compensation point, NO3
- reduction is low, probably because all the NADH produced by the cells is oxidized in the respiratory chain in order to produce ATP to maintain a steady NO3
- transport rate. The total nitrogen (TN) and carbon (TC) contents decreased from darkness to 33 mol m-2 s-1 in blue light. In this range, catabolic processes prevailed over anabolic ones. In contrast, increases in TN and TC contents were observed above the light compensation point. The C : N ratio increased with light intensity, reaching a stable value of 17 at 78 mol m-2 s-1 in blue light. Intracellular NO3
- concentration and NO3
- reduction appear to be directly controlled by light intensity. This external control of [NO3
-]i and the small capacity ofU. rigida to retain incorporated NO3
-, NO2
- and NH4
+ ions may explain its nitrophilic character. 相似文献
8.
Zhang Yuqing Zhan Chengcheng Wang Hui Gao Ya 《Environment, Development and Sustainability》2022,24(8):9777-9808
Environment, Development and Sustainability - This study analyzes the evolution of the land use structure, demographic reconstruction, and social reconstruction of Dachangshan Island, Changhai... 相似文献
9.
Feng Jingchun Tang YunQing Xue Song Zhang Ke 《Environment, Development and Sustainability》2022,24(1):138-155
Environment, Development and Sustainability - The PPP mode of rural water environment governance was conducive to attracting social capital for giving full play to the decisive role of the market... 相似文献
10.