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改进型灰色新陈代谢GM(1,1)模型对外语类生源数的预测修正——基于南通职业大学外国语学院外语类生源数的研究 被引量:1
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作者 任海华 《吕梁教育学院学报》 2011年第2期117-118,133,共3页
通过改进型的灰色新陈代谢GM(1,1)模型对原先常规GM(1,1)模型预测的外语类专业生源数进行有效的修正,取得了更好的预测效果。
关键词 新陈代谢GM(1 1)模型 外语类 生源数 预测 修正
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Evaluation of Environmental Carrying Capacity of Water Resources in Jiangxi Province
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作者 叶志平 孟丽红 《Agricultural Science & Technology》 CAS 2015年第12期2849-2853,共5页
In order to quantitatively evaluate the sustainable development status of water resources in Jiangxi Province, the dynamic changes in ecological footprint, carrying capacity and load index of water resources in Jiangx... In order to quantitatively evaluate the sustainable development status of water resources in Jiangxi Province, the dynamic changes in ecological footprint, carrying capacity and load index of water resources in Jiangxi Province during 2009-2013 were analyzed according to the primary principle and calculation model of ecological footprint. The results showed that in Jiangxi Province during 2009- 2013, the water resources ecological footprint per capita was relatively low; the wa- ter resources utilization level was relatively low; the overall development potential of water resources was great; the water resources ecological carrying capacity per capita and ecological footprint per capita were trended to be increased overall. The changes in water resources ecological footprint are closely related to the social and economic development. Therefore, the industrial structure should be fully adjusted, and the water resources should be scheduled and utilized reasonably so as to pro- mote the protection of water resources and sustainable development of society and economic in Jiangxi Province. 展开更多
关键词 Ecological footprint Water resource load index Ecological carrying ca- pacity
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Morphodynamic evolution of the Xiaoqing River mouth:a Huanghe River-derived mixed energy estuary 被引量:1
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作者 黄海军 刘艳霞 丘仲锋 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第5期889-904,共16页
In an estuary,tidal,wave and other marine powers interact with the coast in different ways and affect estuary morphology as well as its evolution.In the Huanghe(Yellow) River estuaries and nearby delta,there are many ... In an estuary,tidal,wave and other marine powers interact with the coast in different ways and affect estuary morphology as well as its evolution.In the Huanghe(Yellow) River estuaries and nearby delta,there are many small sediment-affected estuaries with a unique morphology,such as the Xiaoqing River estuary.In this study,we investigated the special evolution and genetic mechanism of the Xiaoqing River estuary by analyzing graphic and image data with a numerical simulation method.The results show that NE and NE-E tide waves are the main driving force for sandbar formation.Sediment shoals have originated from huge amounts of sediment from the Huanghe River,with consequent deposition at the Xiaoqing River mouth.The lateral suspended sediments beyond the river mouth move landward.Siltation takes place on the northern shoreline near the river mouth whereas erosion occurs in the south.The deposits come mainly from scouring of the shallow seabed on the northern side of the estuary.Storm surges speed up deposition in the estuary.Development of the sediment shoals has occurred in two steps involving the processes of growth and further southward extension.Although the southward shift increases the river curvature and length,the general eastward orientation of the estuary is unlikely to change.Processes on the adjacent shorelines do not affect the development of the sediment shoals.The study presents a morphodynamic evolutionary model for the Xiaoqing River estuary,with a long-term series cycle,within which a relatively short cycle occurs. 展开更多
关键词 ESTUARY sediment shoal numerical simulation dynamic mechanism mixed energy
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Modeling and Simulation of Hydrogen Storage Device for Fuel Cell Plant
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作者 Akanji Olaitan Lukman Obadele Babatunde Abiodun +2 位作者 Oluranti Sadiku-Agboola Patricia Abimbola Popoola Emmanuel Rotimi Sadiku 《Journal of Chemistry and Chemical Engineering》 2012年第7期604-612,共9页
The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel c... The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energy. 展开更多
关键词 MODELING SIMULATION HYDROGEN STORAGE fuel cell.
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Coseismic slip distribution of 2009 L'Aquila earthquake derived from InSAR and GPS data 被引量:3
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作者 WANG Yong-zhe ZHU Jian-jun +2 位作者 OU Zi-qiang LI Zhi-wei XING Xue-min 《Journal of Central South University》 SCIE EI CAS 2012年第1期244-251,共8页
To better understand the mechanism of the Mw6.3 L'Aquila (Central Italy) earthquake occurred in 2009, global positioning system (GPS) and interferometric synthetic aperture radar (InSAR) data were used to deriv... To better understand the mechanism of the Mw6.3 L'Aquila (Central Italy) earthquake occurred in 2009, global positioning system (GPS) and interferometric synthetic aperture radar (InSAR) data were used to derive the coseismic slip distribution of the earthquake fault. Firstly, based on the homogeneous elastic half-space model, the fault geometric parameters were solved by the genetic algorithm. The best fitting model shows that the fault is a 13.7 km×14.1 km rectangular fault, in 139.3° strike direction and 50.2° southwest-dipping. Secondly, fixing the optimal fault geometric parameters, the fault plane was extended and discretized into 16× 16 patches, each with a size of 1 kmx 1 krn, and the non-uniform slip distribution of the fault was inverted by the steepest descent method with an appropriate smoothing ratio based on the layered crustal structure model. The preferred solution shows that the fault is mainly a normal fault with slight right-lateral strike slip, the maximum slip of 1.01 m is located in the depth of 8.28 km, the average rake is -100.9°, and the total geodetic moment is about 3.34× 1018 N.m (Mw 6.28). The results are much closer than previous studies in comparison with the seismological estimation. These demonstrate that the coseismic fault slip distribution of the L'Aauila earthauake inverted by the crustal model considering layered characters is reliable. 展开更多
关键词 L'Aquila earthquake interferometric synthetic aperture radar global positioning system (GPS) slip distribution
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Study of Chinese Economic "Growth Drag" Caused by Land Resource in the Perspective of the Modified Two-Level CES Production Function 被引量:2
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作者 Yang Yang Wu Cifang 《Chinese Journal of Population,Resources and Environment》 2012年第4期39-43,共5页
The purpose of the study is to measure the "growth drag" according to the characteristic of Chinese land resource.Romer model (2001) holds that every country is inevitably affected by the "growth drag&q... The purpose of the study is to measure the "growth drag" according to the characteristic of Chinese land resource.Romer model (2001) holds that every country is inevitably affected by the "growth drag" due to the limitation of land resource.So it's of profound strategic significance to measure the "growth drag" according to the character of Chinese land resource.Modified two-level CES production function was employed,and this paper modified the hypothesis of the model.The result indicates that the limitation of Chinese land resource casts shadow over the economic development of China,and the growth rate is 0.4618% lower than that without the limitation of land resource.Through implementing the land resource protection policy along with the technology improvement and the substitute effect of other factors to the land resource,China will keep a steady and balanced economic growth. 展开更多
关键词 growth drag modified two-level CES production function land resource economic growth China
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Evaluation of the effects of Alkyl Phenolic compounds on kinetic coefficients and biomass activity in MBBR by means of respirometric techniques 被引量:1
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作者 Bijan Bina Farzaneh Mohammadi +2 位作者 Mohammad Mehdi Amin Hamid Reza Pourzamani Zeynab Yavari 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第4期822-829,共8页
The presence of Alkyl Phenols(APs) in aquatic systems is considered as one of the environmental concerns in recent decades which are generally used as surfactants. APs are endocrine disruptors and estrogen-mimicking,c... The presence of Alkyl Phenols(APs) in aquatic systems is considered as one of the environmental concerns in recent decades which are generally used as surfactants. APs are endocrine disruptors and estrogen-mimicking,causing harmful effects such as feminization and carcinogenesis on aquatic environment and human health.The most commercially important APs are 4-Nonyl Phenol(4-NP) and 4-tert-OctylP henol(4-t-OP). Moving bed biofilm reactor(MBBR), which combined attached and suspended growth advantages, is an advanced biological treatment process for municipal and industrial wastewaters that has drawn considerable attention from many researchers to remove toxic pollutants from wastewater. The aim of this research was to evaluate Bacterial activities and kinetic coefficients in the presence of APs. This study was carried out using laboratory-scale MBBR fed with synthetic wastewater containing 4-NP and 4-t-OP. The reactor was operated at different loads of chemical oxygen demand(COD) and APs and different hydraulic retention time(HRT). The respirometric technique was applied to investigate the effect of APs on heterotrophic and autotrophic activity and kinetic coefficients in biomass obtained from MBBR. Respirometric technique demonstrates a reliable tool in order to assess the biofilm kinetic coefficients and biomass viability to insert in the mathematical models. The calculated kinetic parameters were in the range of conventional and extended aeration activated sludge processes. The results demonstrate that APs have significant inhibitory effects on activity and growth rate of heterotrophic and autotrophic bacteria, heterotrophs have been less affected by the presence of 4-NP and 4-t-OP, and these compounds had greater inhibitory effects on autotrophic bacteria. 展开更多
关键词 Alkyl Phenols Autotrophs Heterotrophs Kinetic coefficients MBBR Respirometric techniques
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Research on the Developmental Trend of Data Journalism under the Background and Time of Big Data
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作者 Hui Zhi 《International Journal of Technology Management》 2016年第1期42-44,共3页
In this paper, we conduct research on the developmental trend of the data journalism under the current background and the time of big data. Big data is not only a concept, but also a description of a state of society... In this paper, we conduct research on the developmental trend of the data journalism under the current background and the time of big data. Big data is not only a concept, but also a description of a state of society: in the era of the big data, data become important social resources and production data, the news media is no exception. In the time of the data had not been so seriously, the core of the news resources is a reporter on the scene to get first-hand material, is based on the reporter can see, smell, feel the fact description, data is often only a supplementary role. However, in today' s era of big data, although the scene is also very important, but based on the various aspects of data mining and analysis and the depth of the formation of information has become more and more important. Our research proposes the novel paradigm for the issues that is meaningful. 展开更多
关键词 Big Data Developmental Trend Data Journalism Contemporary Era and Time.
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Ligation of Caeca Improves Nitrogen Utilization and Decreases Urinary Uric Acid Excretion in Chickens
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作者 Jang-Ho Son 《Journal of Agricultural Science and Technology(A)》 2012年第4期495-504,共10页
This study was carried out to clarify role of ceca in nitrogen nutrition of the chicken. Exp. 1: The effect of cecal ligation on nitrogen utilization and excretion was investigated in chickens fed 5% to 14% protein d... This study was carried out to clarify role of ceca in nitrogen nutrition of the chicken. Exp. 1: The effect of cecal ligation on nitrogen utilization and excretion was investigated in chickens fed 5% to 14% protein diet. Irrespective of dietary protein level and different protein sources, the ligation of cecal decreased uric acid excretion and tended to increase nitrogen utilization and balance with the exception of urea-added 10% protein diet. Exp. 2: The effect of cecal ligation on nitrogen utilization and excretion was investigated in conventional and colostomized chickens fed a 5% protein diet or 5% protein diet plus urea. Total nitrogen excretion and uric acid excretion increased by colostomy were depressed by cecal ligation in chickens. Therefore, nitrogen utilization and balance decreased by colostomy were increased by cecal ligation. Urinary nitrogen excretion was significantly decreased by cecal ligation in colostomized chickens, but the cecal ligation did not change fecal nitrogen excretion in chickens fed either diet. Exp. 3: This experiment was carried out to examine the effects of removal of cecal contents on nitrogen utilization, balance and nitrogen excretion in cecally ligated chickens. Total nitrogen excretion was significantly decreased by washing out the cecal contents with saline or antibiotics. The cecal ligation and the removal of cecal contents significantly decreased uric acid excretion in the excreta. There was a highly inverse relationship between microbial counts in the ceca and an excretory amount of uric acid. Exp. 4: In order to examine effects of cecal ligation on microbial activity, microbes were counted and products of microbial fermentation were determined. The ligation of caeca decreased microbial counts, concentrations of acetic, propionic and butyric acids and ammonia concentration of cecal contents. These results suggest that nitrogen metabolism in chickens is affected by possible changes in cecal fermentation caused by preventing the substances from urine and digesta from entering into the ceca. 展开更多
关键词 Cecal role in nitrogen nutrition cecal ligation COLOSTOMY uric acid excretion chicken.
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DEM Production/Updating Based on Environmental Variables Modeling and Conflation of Data Sources 被引量:1
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作者 Tomaz Podobnikar 《Journal of Civil Engineering and Architecture》 2010年第11期33-44,共12页
Availability of digital elevation models (DEMs) of a high quality is becoming more and more important in spatial studies. Standard methods for DEM creation use only intentionally acquired data sources. Two approache... Availability of digital elevation models (DEMs) of a high quality is becoming more and more important in spatial studies. Standard methods for DEM creation use only intentionally acquired data sources. Two approaches which employ various types of data sets for DEM production are proposed: (1) Method of weighted sum of different data sources with morphological enhancement that conflates any additional data sources to principal DEM, and (2) DEM updating methods of modeling absolute and relative temporal changes, considering landslides, earthquakes, quarries, watererosion, building and highway constructions, etc. Spatial modeling of environmental variables concerning both approaches for (a) quality control of data sources, considering regions, (b) pre-processing of data sources, and (c) processing of the final DEM, have been applied. The variables are called rate of karst, morphologic roughness (modeled from slope, profile curvature and elevation), characteristic features, rate of forestation, hydrological network, and rate of urbanization. Only the variables evidenced as significant were used in spatial modeling to generate homogeneous regions in spatial modeling a-c. The production process uses different regions to define high quality conflation of data sources to the final DEM. The methodology had been confirmed by case studies. The result is an overall high quality DEM with various well-known parameters. 展开更多
关键词 Digital elevation/terrain model environmental variables data quality data conflation/integration spatial modeling.
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Effect of blade pitch angle on aerodynamic performance of straight-bladed vertical axis wind turbine 被引量:3
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作者 张立勋 梁迎彬 +1 位作者 刘小红 郭健 《Journal of Central South University》 SCIE EI CAS 2014年第4期1417-1427,共11页
Wind energy is one of the most promising renewable energy sources, straight-bladed vertical axis wind turbine(S-VAWT) appears to be particularly promising for the shortage of fossil fuel reserves owing to its distinct... Wind energy is one of the most promising renewable energy sources, straight-bladed vertical axis wind turbine(S-VAWT) appears to be particularly promising for the shortage of fossil fuel reserves owing to its distinct advantages, but suffers from poor self-starting and low power coefficient. Variable-pitch method was recognized as an attractive solution to performance improvement, thus majority efforts had been devoted into blade pitch angle effect on aerodynamic performance. Taken into account the local flow field of S-VAWT, mathematical model was built to analyze the relationship between power outputs and pitch angle. Numerical simulations on static and dynamic performances of blade were carried out and optimized pitch angle along the rotor were presented. Comparative analyses of fixed pitch and variable-pitch S-VAWT were conducted, and a considerable improvement of the performance was obtained by the optimized blade pitch angle, in particular, a relative increase of the power coefficient by more than 19.3%. It is further demonstrated that the self-starting is greatly improved with the optimized blade pitch angle. 展开更多
关键词 straight-bladed vertical axis wind turbine pitch angle numerical simulation self-starting power coefficient
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Approximation of Derivative for a Singularly Perturbed Second-Order ODE of Robin Type with Discontinuous Convection Coefficient and Source Term
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作者 R.Mythili Priyadharshini N.Ramanujam 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第1期100-118,共19页
In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving... In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving numerical method is proposed. An e-uniform global error estimate for the numerical solution and also to the numerical derivative are established. Numerical results are presented, which are in agreement with the theoretical predictions. 展开更多
关键词 Singular perturbation problem piecewise uniform mesh discrete derivative discontinuous convection coefficient Robin boundary conditions discontinuous source term.
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Research of Source Parameters of the Yutian Ms7.3 Earthquake in Xinjiang on February 12, 2014
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作者 Wang Peng Zheng Jianchang Wang Yan 《Earthquake Research in China》 CSCD 2016年第1期33-42,共10页
The Ms7. 3 earthquake occurred in Yutian, Xinjiang on February 12, 2014. Based on seismic waveform data before the earthquake and aftershocks of the earthquake sequence, which were recorded by the Xinjiang Regional Di... The Ms7. 3 earthquake occurred in Yutian, Xinjiang on February 12, 2014. Based on seismic waveform data before the earthquake and aftershocks of the earthquake sequence, which were recorded by the Xinjiang Regional Digital Seismic Network, this paper corrected instrument response, propagation path and site response of the S-wave recording spectra. We then calculated with genetic algorithms, on the basis of the Brune model, the source parameters of the 102 M, ≥ 3. 0 Yutian earthquake sequence, seismic moment, apparent stress and corner frequency. The results show that, seismic moment of the earthquake sequence is between 3. 46 × 10^11 -2. 08×10^15N.m, apparent stress is between 1.48 × 10^5 -1.16 ×10^6Pa, mean stress level is 0. 31MPa, and corner frequency is between 1.4-7. 1Hz in the range of 3. 0 -5. 0. By analyzing the apparent stress and corner frequency variation with time, we obtain that apparent stress of earthquakes before the Yutian Ms7. 3 earthquake was significantly higher than the aftershock sequence, but the corner frequency was significantly lower than the aftershock sequence. Apparent stress was at a high level before the main shock, which shows that the main shock zone accumulated higher stress, and then the apparent stress was reduced. The main shock occurred in the process of slow increase. Because of the release of a large amount of stress, after the Ms7. 3 earthquake, the apparent stress was gradually reduced. That was the performance of low stress fracture of aftershocks. 展开更多
关键词 Apparent stress Yutian Ms7. 3 earthquake Corner frequency Sourceparameter
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Isothermal and nonisothermal crystallization kinetics of bio-sourced nylon 69 被引量:6
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作者 Zhijuan Sun Xiao Wang +2 位作者 Fei Guo Chunyue Jiang Qinmin Pan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第5期638-645,共8页
Bio-sourced nylon 69,one of promising engineering plastics,has a great potential in developing sustainable technology and various commercial applications.Isothermal and nonisothermal crystallization kinetics of nylon ... Bio-sourced nylon 69,one of promising engineering plastics,has a great potential in developing sustainable technology and various commercial applications.Isothermal and nonisothermal crystallization kinetics of nylon 69 is a base to optimize the process conditions and establish the structure–property correlations for nylon 69,and it is also highly bene ficial for successful applications of nylon products in industry.Isothermal and nonisothermal crystallization kinetics has been investigated by differential scanning calorimetry for nylon 69,bio-sourced even–odd nylon.The isothermal crystallization kinetics has been analyzed by the Avrami equation,the calculated Avrami exponent at various crystallization temperatures falls into the range of 2.28 and 2.86.In addition,the Avrami equation modi fied by Jeziorny and the equation suggested by Mo have been adopted to study the nonisothermal crystallization.The activation energies for isothermal and nonisothermal crystallization have also been determined.The study demonstrates that the crystallization model of nylon 69 might be a twodimensional(circular)growth at both isothermal and nonisothermal crystallization conditions.Furthermore,the value of the crystallization rate parameter(K)decreases signi ficantly but the crystallization half-time(t1/2)increases with the increase of the isothermal crystallization temperature.To nonisothermal crystallization,the crystallization rate increases as the cooling rate increases according to the analysis of Jeziorny's theory.The results of Mo's theory suggest that a faster cooling rate is required to reach a higher relative degree of crystallinity in a unit of time,and crystallization rate decreases when the relative degree of crystallinity increases at nonisothermal crystallization conditions. 展开更多
关键词 Crystallization kinetics NYLON Activation energy Differential scanning calorimetry
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Data Distribution Mechanism over Opportunistic Networks with Limited Epidemic 被引量:5
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作者 GUO Da CHENG Gang +2 位作者 ZHANG Yong SONG Mei Amanda Matthews 《China Communications》 SCIE CSCD 2015年第6期154-163,共10页
Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution,and Epidemic data distribution means that when each node meets another node,it may copy its own messages and trans... Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution,and Epidemic data distribution means that when each node meets another node,it may copy its own messages and transfer to another node.On the one hand,the copies improve the forwarding rate,and reduce the transmission delay.However,on the other hand,energy consumption increases and network survival time is reduced because the copies consume transmission resource.Therefore,copy number should be under control.In this paper,we first introduce the existing routing strategy based on Epidemic briefly,and present the Epidemic routing protocol analysis model and copy control mechanism based on the limited Epidemic in Opportunistic Networks.Then based on the limited copies scheme(LCS),we propose an energy balance scheme(EBS),the results show that EBS can improve the network survival time. 展开更多
关键词 opportunistic networks delay tol-erant networks Markov chain
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A study on the bioenergy crop production function of land use in China 被引量:2
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作者 ZHANG Kun YU Yao +1 位作者 BAO Chun-hong WANG Tao 《Ecological Economy》 2010年第4期407-414,共8页
Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had ... Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had been analyzes and discusses in this paper.Results show that there were a lot of unused lands and marginal lands which can be planted bioenergy crops to perform the bioenergy crop production function of land use with great potentials;and currently there were no food production problems.Therefore,it was very important for China to emphasize bioenergy crops planting in order to fully use land resources in our country,moderate the energy crisis and increase peasants' income. 展开更多
关键词 Land use Bioenergy crop production function of land use BIOENERGY Bioenergy crops Increase of peasants' income
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Effects of Nitrogen Sources on Nitrate Reductase Activity and Some Physiological Parameters in Psyllium (Plantago ovata F.) under Salinity Stress
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作者 M. Heidaril, H. Steppuhn F. Farzaneh 《Journal of Agricultural Science and Technology》 2011年第4期412-419,共8页
The effects of three nitrogen sources (ammonium, nitrate and ammonium+nitrate) and three salt treatments (0, 100 and 200 mM NaCl) on nitrate reductase activity, proline, soluble protein and carbohydrate contents ... The effects of three nitrogen sources (ammonium, nitrate and ammonium+nitrate) and three salt treatments (0, 100 and 200 mM NaCl) on nitrate reductase activity, proline, soluble protein and carbohydrate contents in psylliom (Plantago ovata) plants were Studied. The nitrate reductase activity tended to increase when NO3- was included in the root-zone solution, but decrease as salinity increased. All N sources stimulated plant growth and nutrient uptake. Shoot and root dry matter tended to decrease as salinity increased, but less so when both NH4+ and NO3- were present. Shoot biomass accumulated to significantly greater quantities under the mixed-N treatments than when produced using either NH4+ or NO3- N-form alone. Although not statistically significant, the root biomasses showed a similar tendency. Generally, leaf proline and soluble shoot carbohydrate contents increased with increasing salinity in contrast to soluble protein which decreased regardless of the N source. Under salinity conditions, the concentration of Na+ in shoot and root tissues was highest in ammonium-N treatment, while that of K+ was highest in the mixed-N treatment. 展开更多
关键词 Salinity stress BIOMASS nitrate reductase Plantago ovata nitrogen form.
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Study of a Parabolic Trough Adequate for the CERER Site (Dakar-Senegal)
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作者 Awa Mar Serigne Thiao +1 位作者 Cheikh Mbow Issakha Youm 《Journal of Energy and Power Engineering》 2016年第5期275-282,共8页
This study presents the modeling of a parabolic trough solar collector. The main objective is to show the influences of the parabolic trough sensor effective efficiency (concentrator optical efflciencies of transmiss... This study presents the modeling of a parabolic trough solar collector. The main objective is to show the influences of the parabolic trough sensor effective efficiency (concentrator optical efflciencies of transmission, reflection, geometrical and the receiver absorption coefficient), of its length, of the mass flow rate on temperatures distributions of the heat fluid and the receiver and on thermal global efficiency (solar conversion efficiency into energy usable). The atmospheric parameters are those of Senegal in April. A prototype existing in the CERER (Center of Studies and Research on Renewable Energies) (Dakar-Senegal) is given as example of application. 展开更多
关键词 Parabolic trough solar collector RECEPTOR EFFICIENCY temperature fluid.
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Energy savings and CO_2 emission reduction by using geothermal heat pumps
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作者 Zheng Xiuhua Du Limeng Chen Huiguang 《Engineering Sciences》 EI 2010年第1期44-48,共5页
The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of t... The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of the fastest growing applications of renewable energy in the world with annual increases of 10 % and much faster in China. With high coefficient of performance (COP) up to 6, GHPs make efficiency of primary energy more than 240 % with assumed a 40 % of electricity generation efficiency, which means energy savings and CO2 emission reduction. In this paper,the geothermal resources and its utilization are talked about, and GHPs technology was introduced. Due to its high efficiency, there will be energy savings by using GHPs. There is also CO2 emission reduction because of using geothermal heat pumps, which is analyzed in the end. 展开更多
关键词 geothermal heat pump energy saving CO2 emission reduction
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Tensiometer as an Irrigation Management Tool and Its Effect on Water Use and Yield of Open Field Grown Cucumber
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作者 Rola Jad Allah Nasser Jeber Yousef Sholi 《Journal of Agricultural Science and Technology(B)》 2016年第5期303-306,共4页
Water is scarce in Palestine and water saving is becoming very important issue. Water management is one of the promising solutions to save water. The purpose of this work was to study the effect of two types of irriga... Water is scarce in Palestine and water saving is becoming very important issue. Water management is one of the promising solutions to save water. The purpose of this work was to study the effect of two types of irrigation regimes on water consumption, yield and growth parameters of cucumber (Cucumis sativus L.) under open field conditions. Cucumbers were grown on a silty-clay soil in Palestinian local conditions. The irrigation regimes used were farmer based irrigation (FI) and tensiometer based irrigation (TI). The results showed that there were no significant difference in crop yield between FI (3.5 kg/plant) and TI (3.4 kg/plant). Dry matter was 14.7% less in TI treatment than that in FI treatment, while water saving was 35.7% in TI treatment. Thus, proper use of tensiometer could be utilized for a better use and management of water resource. Selection of proper water potential set-points according to the cultivation season is crucial for satisfactory results. 展开更多
关键词 TENSIOMETER CUCUMBER water use efficiency water saving.
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