期刊文献+
共找到158篇文章
< 1 2 8 >
每页显示 20 50 100
研究性学习中“资源利用”提示
1
作者 柳栋 《语文教学通讯(初中)(B)》 北大核心 2002年第9期13-13,共1页
今天来的茶客打算对研究性学习“龙门阵”一番,这可是个佐茶的好话题。在他们发表高见之前我先发表一点“低见”。研究性学习的灵魂无疑是创新。因此,它带给我们的观念可能比研究过程更有价值:它真正把教学的落脚点,由教师主体转向了学... 今天来的茶客打算对研究性学习“龙门阵”一番,这可是个佐茶的好话题。在他们发表高见之前我先发表一点“低见”。研究性学习的灵魂无疑是创新。因此,它带给我们的观念可能比研究过程更有价值:它真正把教学的落脚点,由教师主体转向了学生主体。研究性学习是科学精神与人文精神的和谐统一。科学精神包括怀疑、批判、求真、宽容等因素,而研究性学习过程中开放、自主和平等的环境,显然有助于形成这种精神。同时,研究性学习没有追求“成果”那样的功利性目的,研究本身就是目的,它追求的是研究过程中学生智慧的燃烧、精神的拓展和心灵的飞翔,这正是我们所期待的人文精神。我同意这种观点:研究性学习不是“新瓶装旧酒”式的“启发式教学”或“发现式学习”。它不是教师启发学生思考,不是教师张开口袋引诱学生往里钻,不是举一反三而是“无中生有”;它不追求科学结构的构建,不是去欣赏现有科学宫殿的美轮美奂,更不是重复前辈科学家的足迹,而是异想天开的精神探险。当然,这决不意味着学生的研究性学习与教师无关。我认为,在研究性学习中,教师既是与学生同行的平等探求者,又是他们智慧的启迪者和方法的指导者。在具体的技术操作上,教师应该怎么指导?———我们还是听听今天这几位老师的发言吧。 展开更多
关键词 研究性学习 “资源利用” 初中 语文 搜索引擎
下载PDF
专业硕士研究生教学案例库建设研究---以“资源利用与植物保护技术进展”课程为例 被引量:4
2
作者 韩琳 黄小娟 +2 位作者 曹露 孙凌 曾胜兰 《西部素质教育》 2022年第19期28-30,共3页
为了提高课程教学效率和质量,培养德智体美劳全面发展的人才,文章以“资源利用与植物保护技术进展”课程为例,首先对国内外研究现状进行了分析,然后论述了专业硕士研究生教学案例库的建设。
关键词 教学案例库 专业硕士研究生 “资源利用与植物保护技术进展”课程
下载PDF
“资源的开发利用”比较分析——新旧人教版教材对比
3
作者 刘建葫 《数理化解题研究》 2021年第36期84-85,共2页
新教材是依据2017年版课程标准(2020年修订)编制而成,与2003年版课程标准编制的人教版教材对比,更新了大量内容.以人教版新老教材“资源的开发利用”为研究对象,对教材的内容选择、组织编排方面来进行比较研究,并对该节内容在使用新教... 新教材是依据2017年版课程标准(2020年修订)编制而成,与2003年版课程标准编制的人教版教材对比,更新了大量内容.以人教版新老教材“资源的开发利用”为研究对象,对教材的内容选择、组织编排方面来进行比较研究,并对该节内容在使用新教材的教学中提出相应的教学思考. 展开更多
关键词 “资源的开发利用” 教材对比 人教版 高中化学
下载PDF
Effects of Different Water Stresses on Eco-physiological Characteristics of Hippophae rhamnoides Seedlings 被引量:37
4
作者 郭卫华 李波 +2 位作者 黄永梅 赵海霞 张新时 《Acta Botanica Sinica》 CSCD 2003年第10期1238-1244,共7页
In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient ... In order to examine the effects of the decrease of future precipitation on the eco-physiological characteristics of sea buckthorn (Hippophae rhamnoides Linn.) in Huangfuchuan Watershed in Nei Mongol, a water gradient experiment was conducted based on the four specially designed water supply levels, including normal precipitation, slight drought, drought and extreme drought. Results of ANOVE showed that different water gradients had a significant effect on (1) microhabitat factors, such as soil water content and soil temperature; (2) gas exchange, such as net photosynthetic rate, stomatal conductance and transpiration rate; (3) resource use efficiency; and (4) leaf water potential. Water use efficiency of H rhamnoides could increase under moderate water stress, i.e. drought condition, while its net photosynthetic rate and transpiration rate decreased. All kinds of eco-physiological characteristics proved H. rhamnoides seedlings under all water supplies were affected by water stress more or less and that mechanism of intrinsic physiological regulation in seedlings under the extreme drought conditions had the appearance of turbulence to a certain extent. Therefore, H rhamnoides seedlings in Huangfuchuan Watershed could not acclimate to extreme drought conditions. 展开更多
关键词 water stress Hippophae rhamnoides Huangfuchuan Watershed gas exchange water potential resource use efficiency DROUGHT
下载PDF
Research Progress on Resource Utilization of Livestock and Poultry Manure 被引量:6
5
作者 廖青 韦广泼 +3 位作者 江泽普 邢颖 黄东亮 李杨瑞 《Agricultural Science & Technology》 CAS 2014年第1期105-110,共6页
Although mass livestock and poultry breeding brought magnificent econom-ic benefits to the society, it made great harm to the environment. By reviewing the current status of environmental pol ution caused by livestock... Although mass livestock and poultry breeding brought magnificent econom-ic benefits to the society, it made great harm to the environment. By reviewing the current status of environmental pol ution caused by livestock and poultry manure in China, harm-free treatment technology for livestock and poultry manure including fer-tilization technology, feed processing technology and energy technology were elabo-rated so as to address the existing issues in this regard and provide references for resource utilization and eliminating environmental pol ution through modified technical system and environment laws. 展开更多
关键词 Livestock and poultry manure Pollution status Pollution channel Re-source utilization ISSUES PROSPECT
下载PDF
Bamboo resources,utilization and ex-situ conservation in Xishuangbanna,South-eastern China 被引量:1
6
作者 杨清 段柱标 +3 位作者 王正良 何开红 孙启祥 彭镇华 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第1期79-83,共5页
This paper describes the geographical distribution, utilization, cultural value and ex-situ conservation of bamboo resources in Xishuangbanna, Yunan Province, China. Sixty species of bamboo in 19 genera are recorded i... This paper describes the geographical distribution, utilization, cultural value and ex-situ conservation of bamboo resources in Xishuangbanna, Yunan Province, China. Sixty species of bamboo in 19 genera are recorded in Xishuangbanna. The area of natural bamboo forest is 14319 ha, accounting for 5.92% of whole area of Xishuangbanna. The abundant resource of bamboo plays an important role in the economics and culture of national minorities in Xishuangbanna. Xishuangbanna Tropic Botanic Garden, Chinese Academy of Sciences (CAS), started to introduce bamboo species in 1961 and established the ex-situ conservation reserve (8 ha) of bamboo in 1981. Up to now, 211 species in 27 genera collected from tropic and sub-tropic of China and South-east Asia have been planted in the bamboo reserve, of which 11 species have bloomed and seeded, and their seeds were cultivated in Xishuangbanna Tropical Botanic Gardens, CAS, China. 展开更多
关键词 XISHUANGBANNA bamboo resources UTILIZATION ex-situ conservation
下载PDF
Research on Background and Utilization of Germplasm Resources in Maize 被引量:3
7
作者 杨培珠 钟国祥 +4 位作者 谢虹 陈少方 苏立生 刘惠娈 张旭 《Agricultural Science & Technology》 CAS 2011年第10期1464-1467,共4页
[Objective] The research aimed at introducing the background and utilization of germplasm resources in maize.[Method] The research progress on genetic background and utilization of maize germplasm resources was compre... [Objective] The research aimed at introducing the background and utilization of germplasm resources in maize.[Method] The research progress on genetic background and utilization of maize germplasm resources was comprehensively reviewed in this paper,including maize heterotic groups and heterotic patterns,their flexible application in breeding and the utilization of various types of original materials.[Result] The results show that germplasm resource is the premise and basis for maize breeding.In-depth understanding and a reasonable selection of germplasm resources can significantly improve the breeding efficiency and speed up the breeding process.At the same time,it is considered that the selection and construction of original materials in maize breeding can not be limited to the heterotic groups and heterotic patterns,but has to be used reasonablely according to different types of germplasm resources and individual breeding objective and idea as well.[Conclusion] This study had broadened the idea and provided inspiration for the maize breeding practice in China. 展开更多
关键词 MAIZE Germplasm resources Genetic background UTILIZATION
下载PDF
Investigation and Exploitation of New Medicinal Resources of Genus Bupleurum (Umbelliferae) in Qinghai Province and Xizhang (Tibet) Autonomous Region in China 被引量:1
8
作者 李颖 郭济贤 +1 位作者 潘胜利 罗达尚 《Journal of Chinese Pharmaceutical Sciences》 CAS 1993年第1期38-44,共7页
In China,some species of Bupleurum (family Umbelliferae) have been used as Chinese traditional medicine under the name “Chai-Hu” for the treatment of fevers and influenza.In the present paper,the authors report a st... In China,some species of Bupleurum (family Umbelliferae) have been used as Chinese traditional medicine under the name “Chai-Hu” for the treatment of fevers and influenza.In the present paper,the authors report a study on the investigation and exploitation of new medicinal resources of “Chai-Hu” in Qinghai Province and Xizang (Tibet) Autonomous Region where no one has studied this hitherto.18 species,7 varieties,I form of Bupleurum and a new species (Bupleurum qinghaiense) have been discovered.The taxonomy and preliminary phytochemical studies of the roots of three medicinal plants,B.qinghaiense,B.rnarginatum var.stenophyllum and B.smithii var.parvifolium.are reported in this paper. 展开更多
关键词 Bupleurum qinghaiense Bupleurum smithii var parvifolium Bupleurum marginatum var stenophyllum Bupleurum spp in Qinghai and Xizang
下载PDF
Resource Characteristics and Sustainable Utilization of Codonopsis convolve, a Tibetan Medicinal Plant 被引量:2
9
作者 唐晓琴 卢杰 +1 位作者 李连强 兰小中 《Agricultural Science & Technology》 CAS 2017年第8期1384-1390,1395,共8页
In this paper, the resources of Codonopsis convolvulacea subsp. Vinciflora in 13 counties of Tibet were investigated and analyzed by field investigation, sample point-sample set-sample survey, market investigation and... In this paper, the resources of Codonopsis convolvulacea subsp. Vinciflora in 13 counties of Tibet were investigated and analyzed by field investigation, sample point-sample set-sample survey, market investigation and expert visit. The results showed that among the 13 counties, the distribution area of C. convolvulacea ranked as Gongbujiangda County 〉 Zuogong County 〉 Milin County 〉 Mozhugongka County 〉 Lang County 〉 Duilongdeqing County 〉 Chayu County=Jiali County= Mangkang County=Dingqing County=Baqing County=Suo County=Nimu County. The Gongbujiangda County showed the largest distribution, while Zuogong County and Milin County showed relatively small distribution. Chayu County, Jiali County, Mangkang County, Dingqing County, Baqing County, Suo County and Nimu County showed no distribution. The average plant dry weight C. convolvulacea ranked as Duilongdeqing County 〉 Lang County, Gongbujiangda County 〉Milin County 〉Chayu County =Jiali County =Zuogong County =Mangkang County =Dingqing County =Baqing County=Suo County=Mozhugongka County=Nimu County. Among them, Duilongdeqing County showed the largest average plant dry weight. The average plant dry weight of C. convolvulacea in Chayu County, Jiali County, Zuogong County, Mangkang County, Dingqing County, Baqing County, Suo County, Mozhugongka County and Nimu County was all 0 g. The order of biomass of C. convolvulacea in the 13 counties was Mozhugongka County 〉Duilongdeqing County 〉 Lang County 〉 Gongbujiangda County 〉Milin County 〉Zuogong County 〉Dingqing County =Jiali County=Mangkang County=Chayu County=Nimu County=Suo County=Baqing County. Mozhugongka County showed the largest biomass, while the biomass of C. convolvulacea in Dingqing County, Jiali County, Mangkang County, Chayu County, Nimu County, Suo County and Baqing County was all 0 t. The reserve of C. convolvulacea is determined by distribution area habitat and its own growth. In the 13 counties, the reserve of C. convolvulacea ranked as Gongbujiangda County 〉Mozhugongka County 〉 Lang County 〉Zuogong County 〉Milin County 〉Duilongdeqing County 〉Dingqing County=Jiali County=Mangkang County=Chayu County=Nimu County=Suo County=Baqing County. The reserve of C. convolvulacea was biggest in Gongbujiangda County and was relatively small in Dingqing County, Jiali County, Mangkang County, Chayu County, Nimu County, Suo County and Baqing County. Targeting at the problems existing in the utilization of C. convolvulacea, some suggestions are put forward, such as establishment of reserve for medicinal plant ecological industry, artificial cultivation, renewing concept and rational exploitation and utilization. In this paper, the resource characteristics and sustainable utilization of Tibetan medicinal plants were studied so as to provide a theoretical basis for the rational development and utilization of C. convolvulacea in the region. 展开更多
关键词 Codonopsis convolvulacea subsp. Vinciflora Resource characteristics Sustainable development Tibetan medicine
下载PDF
Establishment and Share of Tea Germplasm Database of Yunnan Province 被引量:1
10
作者 蒋会兵 矣兵 王平盛 《Agricultural Science & Technology》 CAS 2011年第12期1966-1971,共6页
[Objective] The paper was to establish tea germplasm database of Yunnan Province,and promote sharing of the tea germplasm resources.[Method] Eight hundred and thirty copies of tea germplasm resources of Yunnan Provinc... [Objective] The paper was to establish tea germplasm database of Yunnan Province,and promote sharing of the tea germplasm resources.[Method] Eight hundred and thirty copies of tea germplasm resources of Yunnan Province were first systematically documented by using Access database software,the generic description of 631 tea resources and characteristic description of 300 tea resources were submitted for e-platform,then linked with the national e-platform for natural scientific and technological resources,and the tea germplasm database of Yunnan Province was established.[Result] Based on the conservation and utilization status of tea germplam resources,the sharing and utilization framework of tea germplam resources was presented.Many problems and suggestion about tea germplasm resources in the process of conservation,documentation concordance and sharing were pointed out.For example,conservation areas were separated and system was not completed;the main traits assessment and identification researching work had not completely accomplished and sharing was inefficient.[Conclusion] The paper laid foundation for standardized,digitized and information-based management of tea germplasm resources. 展开更多
关键词 TEA Germplasm resources DATABASE SHARE
下载PDF
Fenlong Cultivation-the Fourth Set of Farming Methods Invented in China 被引量:16
11
作者 韦本辉 《Agricultural Science & Technology》 CAS 2017年第11期2045-2048,2052,共5页
The basic theory and effect of the new farming method of "Fenlong" cultivation which has been included in the main extension technology of Ministry of Agriculture of the People's Republic of China is fully illustra... The basic theory and effect of the new farming method of "Fenlong" cultivation which has been included in the main extension technology of Ministry of Agriculture of the People's Republic of China is fully illustrated for the first time, and it is the fourth set (generation) of farming modes and methods following manpower, animal and mechanical (tractor) farming. It follows the natural law to achieve soil activation, water saving, oxygen increase, warming and desalination through the active use of natural resources like soil, rainfall and solar energy, thereby promoting a new round of natural agricultural production and quality improvement and water con- servation, which has crop yield increase by 10%-30%, quality improvement of 5%, natural precipitation retaining increase by100%. The characteristics and mechanism are the use of spiral drill for one-time completion of the land preparation by drilling vertically to 30-50 cm of soil layer through high speed peeling. After instant high temperature and many fierce impacts, mechanical frictions, it could achieve the multiplication of the number of loose soil, soil physical modification and expansion of the soil nutrients, reservoirs, oxygen, microorganisms ("Four pools"). Fenlong cultivation can give birth to new farming culture and civilization, and it can achieve the physical "desalinized" transformation and utilization of saline soil. The formation of Fenlong green farming technology system makes it possible to invent the farming tools of "serf-propelled Fenlong machinery" that has got the patent, and it is the method for farmland (dry land, paddy field) Fenlong cultivation, saline-alkali soil smash-ridging cultivation and for the abundance of grass ecology on degraded grassland. The application of Fenlong "4+1" (arable, saline-alkali soil, grasslands, Sponge City+rivers) green development in China can achieve the "double safety" of food and living space. 展开更多
关键词 Fenlong cultivation The fourth set (generation) of new farming methods Activation and utilization of natural resources Improvement of production and quality Water conservation ecology
下载PDF
Study on Sustainable Utilization of Resources of the Damp-heat Karst Mountainous Areas in China
12
作者 周慧杰 周世武 吴良林 《Agricultural Science & Technology》 CAS 2013年第2期369-375,共7页
Damp-heat karst mountainous areas are unique areas in terms of socialeconomic development, resource endowment and eco-environment in China, where natural resources are abundant,unique and diverse. However, fragile eco... Damp-heat karst mountainous areas are unique areas in terms of socialeconomic development, resource endowment and eco-environment in China, where natural resources are abundant,unique and diverse. However, fragile eco-environment, undeveloped economy and culture, and conflict of human and environment should not be ignored. In the research, a framework of integration of resource-development and environment-protection in damp-heat karst was designed on basis of resource and environment integration, which was applied to Daxin County in Guangxi Province. Furthermore, some integration models were proposed, including integration of development of characteristic agricultural resources and protection of eco-environment, integration of development of manganese ore resources and protection of eco-environment, integration of development of tourism resources and protection of ecoenvironment and integration of development of clean energy and protection of eco-environment. 展开更多
关键词 Sustainable utilization of resources Integration of resources and environment Damp-heat karst mountainous areas Daxin County in Guangxi
下载PDF
ESTUARINE AND COASTAL CHALLENGES IN CHINA 被引量:20
13
作者 陈吉余 陈沈良 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2002年第2期174-181,共8页
Estuaries and coasts are conjunctions of four spheres (atmosphere, lithosphere, hydrosphere and biosphere) and important matter and energy convergence/divergence zones, where developed economy, dense population and hi... Estuaries and coasts are conjunctions of four spheres (atmosphere, lithosphere, hydrosphere and biosphere) and important matter and energy convergence/divergence zones, where developed economy, dense population and highly intensive exploitation induce adverse environmental changes and serious destruction of resources, which have great impacts on coastal sustainable development, especially as the highly intensive development in river basins has direct and pronounced effects on estuaries and their adjacent coasts. In the new century, China’s estuaries and coast are faced with four main challenges: sharp decrease of sediment discharge into the sea, rapid increase of pollution matter into the sea, loss of coastal wetland, and the impacts of global sea level rise on the coastal lowlands of China. Therefore, it is undoubtedly very important and urgent to carry out studies on estuarine and coastal environmental changes, in order to resolve the issue of national sustainable development, especially that of rational use of coastal zone resources. 展开更多
关键词 estuaries and coasts anthropogenic activities environmental changes resource utilization great challenges
下载PDF
Urban Water Resource Utilization Efficiency in China 被引量:14
14
作者 SHI Tiange ZHANG Xiaolei +1 位作者 DU Hongru SHI Hui 《Chinese Geographical Science》 SCIE CSCD 2015年第6期684-697,共14页
The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis ... The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis (SBM-DEA) has been widely used in energy efficiency and environmental efficiency analyses in recent years. Based on this model, data from 316 cities were examined and a category method was employed involving three different sorting techniques to empirically evaluate the efficiency of urban water re- source utilization in China between 2000 and 2012. The overall efficiency (OE) of urban water resource utilization in China was initially low, but has improved over the past decade. The scale efficiency (SE) was higher than the pure technological efficiency (PTE); PTE is a major determining factor of OE, and has had an increasingly significant effect. The efficiency of water resource utilization varied ac- cording to the region, urban scale, and economic function. The OE score for the eastern China was higher than for the rest of the region, and the OE score for the western China was higher than for the central China. The OE score for urban water resource utilization has improved with urban expansion, except in the case of small cities. The SE showed an inverted U-shaped' trend with increasing urban expansion. The OE of urban water utilization in comprehensive functional cities was greater than in economic specialization cities, and was greater in heavy industry specialization cities than in other specialization cities. This study contributes to the field of urban water resource management by examining variations in efficiency with urban ~ezle 展开更多
关键词 urban water resource utilization efficiency urban scale undesirable outputs a slacks-based measure for data envelopmentanalysis (SBM-DEA) China
下载PDF
网络环境下研究性学习的实践与反思 被引量:2
15
作者 唐夏芸 《闽江学院学报》 2006年第5期105-107,共3页
通过列举“资源利用——主题探究——合作学习”模式在研究性学习中的应用,阐述了网络环境下研究性学习的可行性,反思了影响网络环境下研究性学习的重要因素,并提出实现研究性学习目标的策略.
关键词 网络环境 研究性学习 “资源利用——主题探究——合作学习”模式
下载PDF
Effect of Limited Single Irrigation on Yield of Winter Wheat and Spring Maize Relay Intercropping 被引量:10
16
作者 ZHANG Bu-Chong HUANG Gao-Bao LI Feng-Min 《Pedosphere》 SCIE CAS CSCD 2007年第4期529-537,共9页
A field experiment was conducted during the 2002/2003 cropping season of winter wheat (Triticum aestivum) and spring maize (Zea mays) to evaluate the effect of limited single drip irrigation on the yield and water... A field experiment was conducted during the 2002/2003 cropping season of winter wheat (Triticum aestivum) and spring maize (Zea mays) to evaluate the effect of limited single drip irrigation on the yield and water use of both crops under relay intercropping in a semi-arid area of northwestern China. A controlled 35 mm single irrigation, either early or late, was applied to each crop at a certain growth stage. Soil water, leaf area, final grain yield and yield components such as the thousand-grain weight, length of spike, fertile spikelet number, number of grains per spike, and grain weight per spike were measured, and water use efficiency and leaf area index were calculated for the irrigated and non-irrigated relay intercropping treatments and sole cropping controls. The results showed that yield, yield components, water use efficiency, and leaf area index in the relay intercropping treatments were affected by limited single drip irrigation during various growth stages of wheat and maize. The total yields in the relay intercropping treatment irrigated during the heading stage of wheat and the heading and anthesis stage of maize were the highest among all the treatments, followed by that irrigated during the anthesis stage of wheat and silking stage of maize; so was the water use efficiency. Significant differences occurred in most yield components between the irrigated and non-irrigated relay-intercropping treatments. The dynamics of the leaf area index in the relay-intercropped or solely cropped wheat and maize showed a type of single-peak pattern, whereas that of the relay intercropping treatments showed a type of double-peak pattern. Appropriately, limited single irrigation and controlled soil water content level could result in higher total yield, water use efficiency, and leaf area index, and improved yield components in relay intercropping. This practice saved the amount of water used for irrigation and also increased the yield. Therefore, heading stage of wheat and heading and anthesis stage of maize were suggested to be the optimum limited single irrigation time for relay-intercropped wheat and maize in the semi-arid area. 展开更多
关键词 leaf area index limited single irrigation water use efficiency winter wheat and spring maize relay intercropping yield and yield components
下载PDF
Potential Effect of Conservation Tillage on Sustainable Land Use: A Review of Global Long-Term Studies 被引量:34
17
作者 WANG Xiao-Bin CAI Dian-Xiong +2 位作者 W.B.HOOGMOED O.OENEMA U.D.PERDOK 《Pedosphere》 SCIE CAS CSCD 2006年第5期587-595,共9页
Although understood differently in different parts of the world, conservation tillage usually includes leaving crop residues on the soil surface to reduce tillage. Through a global review of long-term conservation til... Although understood differently in different parts of the world, conservation tillage usually includes leaving crop residues on the soil surface to reduce tillage. Through a global review of long-term conservation tillage research, this paper discusses the long-term effect of conservation tillage on sustainable land use, nutrient availability and crop yield response. Research has shown several potential benefits associated with conservation tillage, such as potential carbon sequestration, nutrient availability, and yield response. This research would provide a better perspective of the role of soil conservation tillage and hold promise in promoting application of practical technologies for dryland farming systems in China. 展开更多
关键词 conservation tillage NO-TILL reduced tillage residue management
下载PDF
A Sand Control and Development Model in Sandy Land Based on Mixed Experiments of Arsenic Sandstone and Sand: A Case Study in Mu Us Sandy Land in China 被引量:13
18
作者 WANG Ni XIE Jiancang HAN Jichang 《Chinese Geographical Science》 SCIE CSCD 2013年第6期700-707,共8页
Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,w... Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,which causes worse local agricultural conditions accordingly.Many physical properties of arsenic sandstone is complementary with that of sand,arsenic sandstone is therefore supposed to be blended to enhance water productivity and arability of sandy land.Container experiments are carried out to study the enhancement of water holding capacity of the mixture,the blending ratio of arsenic sandstone and sand,and the proper size of the arsenic sandstone particles,respectively.The results of the experiments show that particle size of 4 cm with a ratio of 1∶2 between arsenic sandstone and sand are the proper parameters on blending.Both water content and fertility increase after blending.Water use efficiency in the mixture is 2.7 times higher than that in sand by the water release curves from experiments.Therefore,a new sand control and development model,including arsenic sandstone blending with sand,efficient water irrigation management and reasonable farming system,is put forward to control and develop sandy land so that water-saving agriculture could be developed.Demonstration of potato planting about 153.1 ha in area in the Mu Us Sandy Land in China indicates that water consumption is 3018 m3/ha in the whole growth period.It means that about 61%of irrigation water can be saved compared with water use in coarse sand without treatment.Recycle economic mode and positive feedback of sand resource-crop planting-soil resource are constructed,which changes sand into arable soil and make it possible to develop water-saving agriculture on it.The proposed model will be helpful for soil-water resources utilization and management in the Mu Us Sandy Land. 展开更多
关键词 soil-water resource arsenic sandstone sand control and development model water-saving effect Mu Us Sandy Land
下载PDF
Estimating regional coal resource efficiency in China using three-stage DEA and bootstrap DEA models 被引量:10
19
作者 Cui Yijia Huang Guoliang Yin Ziyong 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第5期861-864,共4页
Based on three-stage data envelopment analysis(DEA) model estimates of resource utilization efficiency of coal,we selected 29 provinces from China's 2012 input-output data and used the bootstrap DEA model to corre... Based on three-stage data envelopment analysis(DEA) model estimates of resource utilization efficiency of coal,we selected 29 provinces from China's 2012 input-output data and used the bootstrap DEA model to correct the bias.The results show that the mean overall technical efficiency,pure technical efficiency,and scale efficiency was 0.833,0.998,and 0.711 in 2012,respectively.Moreover,the comprehensive technical efficiency score indicates that the scale is invalid.Area utilization efficiencies for the eastern,central,and western regions were 0.917,0.731,and 0.629,respectively.The results prove that there are significant differences in the distribution of coal resources utilization efficiency across regions. 展开更多
关键词 Coal resource efficiency Three-stage DEA Bootstrap DEA Technical efficiency
下载PDF
Distributed Power Control for Energy Conservation in Hybrid Cellular Network with Device-to-Device Communication 被引量:13
20
作者 TANG Rui ZHAO Jihong QU Hua 《China Communications》 SCIE CSCD 2014年第3期27-39,共13页
Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of sh... Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of short-range communication,we devise a series of distributed power control(DPC) schemes for energy conservation(EC)and enhancement of radio resource utilization in the hybrid system.Firstly,a constrained opportunistic power control model is built up to take advantage of the interference avoidance methodology in the presence of service requirement and power constraint.Then,biasing scheme and admission control are added to evade ineffective power consumption and maintain the feasibility of the system.Upon feasibility,a non-cooperative game is further formulated to exploit the profit in EC with minor influence on spectral efficiency(SE).The convergence of the DPC schemes is validated and their performance is confirmed via simulation results. 展开更多
关键词 Device-to-Device communication distributed power control energy conservation interference avoidance biasing scheme admission control non-cooperative game
下载PDF
上一页 1 2 8 下一页 到第
使用帮助 返回顶部