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末级固定灌溉渠道防渗经济长度计算
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作者 隆文非 谢光国 《四川水力发电》 2001年第4期8-9,28,共3页
通过对末级固定灌溉渠道产生的各种效益及费用的近似量化 ,寻求净效益值最大。在 VB6 .0环境下编制计算程序并进行实例分析 ,得出灌溉渠道防渗处理的防渗经济长度的一般性关系。这对于量大面广的末级固定灌溉渠道在资金有限的情况下 ,... 通过对末级固定灌溉渠道产生的各种效益及费用的近似量化 ,寻求净效益值最大。在 VB6 .0环境下编制计算程序并进行实例分析 ,得出灌溉渠道防渗处理的防渗经济长度的一般性关系。这对于量大面广的末级固定灌溉渠道在资金有限的情况下 ,达到既节省费用 ,又有利于农业生产 ,对达到节水的目的是十分有意义的。 展开更多
关键词 灌溉渠道 防渗 经济长度 渠道防渗 计算
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市域轨道交通线路合理经济长度研究 被引量:3
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作者 王少楠 梁青槐 《铁道运输与经济》 北大核心 2011年第10期1-6,共6页
在理论分析的基础上,从经济角度出发研究市域轨道交通合理的经济长度。以乘客旅行次数需求密度函数为基础,建立市域轨道交通线路长度效益函数和成本函数,其中效益函数包括旅客时间节省效益函数和票价收入效益函数;成本函数包括建设成本... 在理论分析的基础上,从经济角度出发研究市域轨道交通合理的经济长度。以乘客旅行次数需求密度函数为基础,建立市域轨道交通线路长度效益函数和成本函数,其中效益函数包括旅客时间节省效益函数和票价收入效益函数;成本函数包括建设成本函数和运营成本函数,效益函数和成本函数相加即为市域轨道交通社会效益最大化的目标函数。通过建立社会效益函数的非线性函数,建立模型求解,得出合理的市域轨道交通经济长度。 展开更多
关键词 市域轨道交通 合理经济长度 效益函数 成本函数
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末级固定灌溉渠道经济防渗长度研究 被引量:1
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作者 隆文非 谢光国 《四川水利》 2000年第5期25-27,共3页
建立效益分析的数学模型 ,可得出末级灌溉渠道防渗处理净效益最大的防渗长度 ,即经济防渗长度 ;并通过实例分析 ,计算出采取不同防渗措施时的经济长度占渠道总长的范围。
关键词 灌溉渠道 经济防渗长度 末级固定渠道
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对中国经济波动周期长度的估算
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作者 杨战民 吴明鑫 《陕西师范大学学报(自然科学版)》 CAS CSCD 北大核心 2003年第z1期14-16,共3页
对中国经济的波动周期进行了分析 ,利用萨缪尔森的乘数 加速数模型 。
关键词 萨缪尔森的宏观经济模型 经济波动的周期长度 估算
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配水渠道经济衬砌长度分析
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作者 马振庆 《海河水利》 北大核心 1993年第1期52-55,共4页
当配水渠道为土渠时,由于渠道较长且单位流量的湿周较大,相应渠道的渗漏损失也较大.如果衬砌渠道就能控制渠道渗漏损失、提高水的利用率.而渠道衬砌长度的大小直接影响工程效益的发挥.从衬砌工程经济效益观点出发,应用“边际原理”提出... 当配水渠道为土渠时,由于渠道较长且单位流量的湿周较大,相应渠道的渗漏损失也较大.如果衬砌渠道就能控制渠道渗漏损失、提高水的利用率.而渠道衬砌长度的大小直接影响工程效益的发挥.从衬砌工程经济效益观点出发,应用“边际原理”提出了以工程节水净效益最大为依据的、确定渠道经济衬砌长度的方法. 展开更多
关键词 配水渠道 边际原理 经济衬砌长度 效益费用分析
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展望新千年的中国经济 被引量:2
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作者 林毅夫 《宁波经济(财经视点)》 2001年第1期11-12,共2页
迈进新千年的中国经济到底往何处去,为世人所关心!本文拟就未来中国经济可能的走向,改革中积累下来的诸多问题如何解决等作些分析.
关键词 中国 经济增长 经济长度 体制改革
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R22和R410A多联机配管长度理论分析 被引量:3
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作者 申晓宇 朱蒙佳 张帆 《制冷与空调(四川)》 2009年第4期114-118,共5页
随着多联机的广泛使用,多联机配管长度对机组性能的影响一直是业内关注的问题。配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需充注大量制冷剂的问题。这就造成多联机从理论上具有节能潜力,而... 随着多联机的广泛使用,多联机配管长度对机组性能的影响一直是业内关注的问题。配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需充注大量制冷剂的问题。这就造成多联机从理论上具有节能潜力,而实际使用中则未必。就机组配管长度对机组的影响进行了理论分析计算,讨论了多联机的经济配管长度。 展开更多
关键词 多联机 经济配管长度 效率 理论计算分析
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整浆联合机生产色织织轴的效益分析
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作者 李凤兰 张立 侯桂云 《上海纺织科技》 北大核心 2007年第11期27-30,59,共5页
计算了单个色织品种在传统工艺流程与在整浆联合机生产的综合费用差额,并进一步针对在两条生产线连续生产不同色织品种回浆的回用差异,计算出了各自的"临界经济长度",从而确定了各自的"经济长度"范围,将该范围内的... 计算了单个色织品种在传统工艺流程与在整浆联合机生产的综合费用差额,并进一步针对在两条生产线连续生产不同色织品种回浆的回用差异,计算出了各自的"临界经济长度",从而确定了各自的"经济长度"范围,将该范围内的色织品种采用整浆联合机生产流程,经济效益非常显著。 展开更多
关键词 色织 整浆联合机 工艺 经济长度 效益
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R22和R410A多联式空调机组经济配管长度理论研究 被引量:8
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作者 盛健 周志钢 +2 位作者 吴兆林 虞海峰 郝玉影 《建筑科学》 北大核心 2009年第10期76-80,共5页
随着多联机的广泛使用,多联机配管长度对机组性能的影响成为业内人士关注的问题。配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需充注大量制冷剂的问题,造成了多联机在理论上具有节能潜力,而... 随着多联机的广泛使用,多联机配管长度对机组性能的影响成为业内人士关注的问题。配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需充注大量制冷剂的问题,造成了多联机在理论上具有节能潜力,而在实际使用中未必有效的现象。本文就机组配管长度对机组的影响进行了理论分析计算,讨论了多联机的经济配管长度。 展开更多
关键词 多联机 经济配管长度 效率 理论计算分析
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超高压输电在输变电工程中的应用探讨 被引量:2
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作者 陈亮 《南昌水专学报》 2001年第4期26-30,共5页
远距离超高压输电是解决我国能源和电力负荷分布不平衡的最佳方法 .从经济角度分析 ,超高压交、直流输电有一“临界经济长度” ,超过这一长度 。
关键词 超高压直流输电 超高压交流输电 临界经济长度 输电方案
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轻型支架放顶煤工作面技术参数的确定
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作者 樊栓保 吕志强 杨凤友 《煤矿开采》 2001年第4期24-25,42,共3页
探讨了轻型支架放顶煤工作面合理倾斜长度、经济走向长度与盈亏平衡产量之间的关系 。
关键词 轻型支架放顶煤工作面 合理倾斜长度 经济走向长度 盈亏平衡产量 回采工艺
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滴灌系统田间管网优化设计分析
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作者 艾木都力·吾守尔 《水科学与工程技术》 2019年第5期16-18,共3页
在调研新疆地区滴灌工程基础上,分析了地区现行滴灌工程管网布置及长度确定方式,提出运用毛管最大长度计算公式和经济指标作为重要衡量参数,确定田间毛管布置的最经济长度。结果表明,在毛管间距相等情况下,毛管铺设经济长度会随滴头间... 在调研新疆地区滴灌工程基础上,分析了地区现行滴灌工程管网布置及长度确定方式,提出运用毛管最大长度计算公式和经济指标作为重要衡量参数,确定田间毛管布置的最经济长度。结果表明,在毛管间距相等情况下,毛管铺设经济长度会随滴头间距增加、流量减小而增加。同时,增加灌水小区面积,田间毛管经济长度亦会增加。 展开更多
关键词 滴灌系统 田间工程 管网 毛管经济长度
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Characteristics and Process of Land Use Changes in the Yangtze River Delta, China 被引量:17
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作者 PULIJIE YANGGUISHAN 《Pedosphere》 SCIE CAS CSCD 2001年第3期193-198,共6页
As one of the developing countries China has an arable land per capita far below the world’s average level. With a high-density population and the quick development of economy and urbanization, the Yangtze River Delt... As one of the developing countries China has an arable land per capita far below the world’s average level. With a high-density population and the quick development of economy and urbanization, the Yangtze River Delta shows the typical characteristics of land use in developed regions of China, which are: high land reclamation rate and low arable land per capita; intensive land use and high output value; and rapid increasing of construction land area and fast diminishing of arable lands. The analysis indicates that the process of the arable land changes in the Yangtze River Delta could be divided into four different change stages over the past 50 years. 展开更多
关键词 arable land use CHARACTERISTICS CHANGE PROCESS the Yangtze River Delta
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Culture techniques and growth characteristics of Dinophysis acuminata and its prey 被引量:1
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作者 佟蒙蒙 周启星 +3 位作者 KULIS M.David 江天久 齐雨藻 ANDERSON M.Donald 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第6期1230-1239,共10页
The dinoflagellate Dinophysis acurninata Claparede & Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Pa... The dinoflagellate Dinophysis acurninata Claparede & Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D. acuminata in culture using a three-step feeding protocol in which the cryptophyte, Geminigera cryophila, is fed to Myrionecta rubra (=Mesodinium rubrum), a ciliate that is in turn fed to D. acuminata. In this paper, we present the details of culturing D. acuminata from the Northeastern United States. The protocols described herein can be adopted for laboratory studies of this species. The effects of temperature on the growth and ingestion rates of D. acuminata were also examined. The results show that D. acuminata growth rate was 0.23/d at 10℃ and 0.11/d at 4℃when fed M. rubra prey. The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10℃, although the rate decreased slightly at 4℃. In overall, temperature showed a greater influence on growth rate of D. acuminata than on the ingestion rate under the study conditions, and the quantity of available food was also an important regulator to D. acurninata growth. 展开更多
关键词 Dinophysis acuminata Myrionecta rubra Geminigera cryophila growth rate ingestion rate
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Modeling an emissions peak in China around 2030: Synergies or trade-offs between economy, energy and climate security 被引量:28
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作者 CHAI Qi-Min XU Hua-Qing 《Advances in Climate Change Research》 SCIE 2014年第4期169-180,共12页
China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain differ... China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain different views on pathways that could achieve such a transformation. The essential question is whether radical or incremental reforms are required in the coming decades. This study explores relevant pathways in China beyond 2020, particularly modeling the major target choices of carbon emission peaking in China around 2030 as China-US Joint Announcement by an integrated assessment model for climate change IAMC based on carbon factor theory. Here scenarios DGS-2020, LGS2025, LBS-2030 and DBS-2040 derived from the historical pathways of developed countries are developed to access the comprehensive impacts on the economy, energy and climate security for the greener development in China. The findings suggest that the period of 2025--2030 is the window of opportunity to achieve a peak in carbon emissions at a level below 12 Gt CO2 and 8.5 t per capita by reasonable trade-offs from economy growth, annually -0.2% in average and cumulatively -3% deviation to BAU in 2030. The oil and natural gas import dependence will exceed 70% and 45% respectively while the non-fossil energy and electricity share will rise to above 20% and 45%. Meantime, the electrification level in end use sectors will increase substantially and the electricity energy ratio approaching 50%, the labor and capital productivity should be double in improvements and the carbon intensity drop by 65% by 2030 compared to the 2005 level, and the cumulative emission reductions are estimated to be more than 20 Gt CO2 in 2015-2030. 展开更多
关键词 Emission peaking Energy cap Integrated assessment
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‘Middle-Income Trap’ and ‘High-Income Waft': Challenges and Opportunities to China 被引量:1
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作者 刘世锦 张军扩 +1 位作者 侯永志 刘培林 《China Economist》 2012年第1期4-28,共25页
The history of international industrialization shows that Latin American countries and former Soviet Union and Eastern European countries experienced a siginificant drop in economic growth and fell into the middle-inc... The history of international industrialization shows that Latin American countries and former Soviet Union and Eastern European countries experienced a siginificant drop in economic growth and fell into the middle-income trap when their per capita GDP reached 4,000-7,000 international dollar (based on the 1990 prices) as a result of long-term implemented import-oriented strategy and planned economic system. Fortunately, China adopted reform and opening-up policy beginning at a lower development phase and achieved sustained high-speed growth for more than thirty years. Currently, China has surpassed the phase which the above-mentioned countries fell into the middle-income trap. On the other side, experiences of successful runner-ups show that when per capita GDP reached II,000 international dollar (based on the 1990 prices), economic growth speed will present regularly "natural drop ". Without internal and external shocks, China's economy is expected to reach this level by 2015 and the potential growth rate will possibly drop significantly. In this regard, China's toughest challenges will be whether it can effectively prevent and solve the financial risks accumulated during high-speed growth and make a shift to innovation-driven growth model Time is pressing for addressing the above challenges. A fundamental change in the growth model depends on the intensification of reform, in particular, the promotion of an "participatory and facilitative reform "approach. 展开更多
关键词 middle income trap high income wall China's economic growth
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Effect of Seawater Stress on Physiological and Biochemical Responses of Five Jerusalem Artichoke Ecotypes 被引量:15
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作者 LONG Xiao-Hua CHI Jin-He LIU Ling LI Qing LIU Zhao-Pu 《Pedosphere》 SCIE CAS CSCD 2009年第2期208-216,共9页
Three treatments consisting of 0%,15%,and 30%seawater were investigated to analyse the ecotypic variabilities among five populations of Jerusalem artichoke(Helianthus tuberosus)regarding their responses to seawater st... Three treatments consisting of 0%,15%,and 30%seawater were investigated to analyse the ecotypic variabilities among five populations of Jerusalem artichoke(Helianthus tuberosus)regarding their responses to seawater stress under a hydroponic culture system.Analyses were done 2,4,and 6 days after treatments.The 15%and 30%seawater treatments reduced the growth rates of roots and shoots of H.tuberosus populations.The activities of superoxide dismutase, peroxidase,and catalase majored in the leaves were stimulated under the seawater stress.The electrolyte leakage and malondialdehyde contents of the leaves were also stimulated owing to seawater stress.The contents of proline and soluble- sugars in the leaves increased significantly with increasing seawater concentrations.The concentrations of Na+,K+,and Cl-in the aerial parts and roots increased with an increase in the seawater concentration throughout the experimental period.There were ecotypic differences among the five populations of H.tuberosus as evidenced by the analyses of the above items in both aerial parts and roots under seawater treatment.The magnitude of the ecotypic variance components indicated that a substantial proportion of the total variation for these physiological and biochemical responses were owing to ecotype,indicating the possibility of improvement through hybridization and selection. 展开更多
关键词 antioxidative enzyme Helianthus tuberosus inorganic and organic solutes seawater stress
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The effects of land market development on economic growth: an empirical analysis based on Chinese panel data,1999-2005 被引量:1
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作者 YANG Hong-mei 《Ecological Economy》 2010年第1期88-95,共8页
Optimized land resources allocation is important for economic growth because land is one of the basic elements for economic development. And urban land resources allocation has had an increasingly important influence ... Optimized land resources allocation is important for economic growth because land is one of the basic elements for economic development. And urban land resources allocation has had an increasingly important influence since the Chinese socialist market economy system was established. This paper estimates the production function of both the secondary and the tertiary industries of China's 31 provinces, autonomous regions and municipalities directly under the central government through an analysis of the panel data of the total output value of the secondary and the tertiary industries, invested capital, invested labor jorces and the land market-jeatured management of the above-mentioned regions during the period of 1999-2005. and examines the positive influence of the above- mentioned factors on regional economic output, This study concludes that urban economic output is positively related with the level of urban land resources market-featured management, since the rate of economic growth of those regions approximates 14. 7% under the condition of urban land market running during the period of 1999-2005. 展开更多
关键词 Land market Economic growth Panel data Regional difference
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WTO Analysis:What's in World Trade 2007?
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《China's Foreign Trade》 2008年第11期62-66,共5页
World trade growth slid to 5.5 per- cent last year from 8.5 percent in 2006 and may grow even more slowly in 2008-at about 4.5 percent-as sharp economic deceleration in key developed countries is only partly offset by... World trade growth slid to 5.5 per- cent last year from 8.5 percent in 2006 and may grow even more slowly in 2008-at about 4.5 percent-as sharp economic deceleration in key developed countries is only partly offset by continuing strong growth in emerging economies。 展开更多
关键词 世界贸易组织 中国 经济增长速度 商品交易 对外贸易
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Elasticity Ratio of Resource Consumption and the Resource Consumption
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作者 Meng Weihua Zhu Dajian Zhou Xinhong 《Chinese Journal of Population,Resources and Environment》 2009年第1期51-56,共6页
Today the resources are becoming scarcer, which should not be regarded as unexhausted any more. Correspondingly, the production would be constrained by the scarcity of resources clearly. Then the economic researchers ... Today the resources are becoming scarcer, which should not be regarded as unexhausted any more. Correspondingly, the production would be constrained by the scarcity of resources clearly. Then the economic researchers would pay much more attention to reducing the consumption of natural resources in the future. Therefore this paper brings foreword the conception of elasticity ratio of resource consumption based on the concept of elasticity and analyzes the relationship between the parameters. For the certain relationships between the elasticity ratio of resource consumption and resource consumption, this paper will try to reveal, to keep economy growing while resource consumption reducing, what conditions should be met as to the relationships among resource productivity, its growth rate, energy saving efficiency, economic growth rate and elasticity ratio of resource consumption. This paper proves the relationship between the China's energy consumption and economy growth using statistic data from 1978 to 2003. 展开更多
关键词 elasticity ratio of resource consumption resource productivity economic growth rate energy saving efficiency resource consumption
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