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Effects of the nitrification inhibitor nitrapyrin and the plant growth regulator gibberellic acid on yield-scale nitrous oxide emission in maize fields under hot climatic conditions 认领
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作者 Khadim DAWAR Kamil SARDAR +5 位作者 Mohammad ZAMAN Christoph MÜLLER Alberto SANZ-COBENA Aamir KHAN Azam BORZOUEI Ana Gabriela PÉREZ-CASTILLO 《土壤圈:英文版》 SCIE CAS CSCD 2021年第2期323-331,共9页
Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N2O)emission and increase crop yield.However,no concrete information on their mitigation of N2O emission is available under soil ... Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N2O)emission and increase crop yield.However,no concrete information on their mitigation of N2O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N2O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha-1)alone,urea in combination with nitrapyrin(700 g ha-1),urea in combination with GA_3(60 g ha-1),and urea in combination with nitrapyrin and GA_3.The N2O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N2O emission by 39%–43%and decreased yield-scaled N2O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N2O emission,improve N response efficiency,and increase maize yield. 展开更多
关键词 fertilizer use efficiency greenhouse gas emission mitigation N response efficiency N uptake efficiency N2O flux plant growth hormone UREA
基本公共卫生服务效率及其影响因素 认领
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作者 柯思思 张刚 +1 位作者 朱朝阳 严亚琼 《中国卫生资源》 北大核心 2021年第1期75-78,共4页
目的基于2017年武汉市13个地区基层医疗卫生机构的横断面数据,分析武汉市基本公共卫生服务效率及其主要影响因素。方法采用松弛测度(slack-based-measure,SBM)-超效率数据包络分析(data envelopment analysis,DEA)模型,对武汉市基本公... 目的基于2017年武汉市13个地区基层医疗卫生机构的横断面数据,分析武汉市基本公共卫生服务效率及其主要影响因素。方法采用松弛测度(slack-based-measure,SBM)-超效率数据包络分析(data envelopment analysis,DEA)模型,对武汉市基本公共卫生服务效率进行测算,通过Tobit回归分析进一步探讨其影响因素。结果2017年武汉市13个地区基本公共卫生服务的超效率、纯技术效率、规模效率几何均数分别为1.073、1.213、0.884。其中76.9%的地区为DEA有效,若非DEA有效地区能达到DEA有效,全市可少开办11家基层医疗卫生机构、减少1451张病床、节省6983万元基本公共卫生服务补助经费。60岁及以上老年人比例、平均期望寿命、每千人口卫生技术人员数、每千人口床位数对武汉市基本公共卫生服务效率的影响具有统计学意义。结论武汉市基本公共卫生服务效率地区差异较大,规模效率是制约基本公共卫生服务效率的关键因素。60岁及以上老年人比例越高、平均期望寿命越长、每千人口卫生技术人员数越多,基本公共卫生服务效率越低;每千人口床位数越多,基本公共服务效率越高。针对这些因素,需提高老年人健康管理水平,优化机构人员配置,合理调整机构规模,重视基本公共卫生服务的公益性。 展开更多
关键词 基本公共卫生服务basic public health service 数据包络分析data envelopment analysis DEA Tobit模型Tobit model 服务效率service efficiency 纯技术效率pure technical efficiency 规模效率scale efficiency
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Quadratic Boost Converter: An Analysis with Passive Components Losses 认领
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作者 Modou Badiane Prince Abdoul Aziz Honadia +1 位作者 Bernard Zouma Fabé Idrissa Barro 《应用科学(英文)》 2021年第2期202-215,共14页
The Cascaded Connected Single Switch Quadratic Boost (C<sup>2</sup>S<sup>2</sup>-QB) is studied first from its ideal model, then with semi-real model taking into account resistive losses throug... The Cascaded Connected Single Switch Quadratic Boost (C<sup>2</sup>S<sup>2</sup>-QB) is studied first from its ideal model, then with semi-real model taking into account resistive losses through the inductors and the capacitor. The continuous conduction mode equations, describing these different models are established, taking into account losses through passive components. From these equations, the voltage gain and the efficiency are determined for the semi-real model. The voltage gain and the efficiency are then analyzed versus duty cycle and the influence of passive component losses on the performance of the quadratic boost converter is carried out for the semi-real model. It has been showed that the quality of the passive components of a converter plays an important role in the quality of the conversion. However, not all passives components affect the converter in the same way. 展开更多
关键词 Quadratic Boost LOSSES Gain Factor EFFICIENCY
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Determination of Airways Resistance, Volumetric Efficiency and Development of Ventilation Model of Rosh Pinah Zinc Mine Namibia 认领
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作者 Jeremia Kalenga Jide Muili Akande 《矿物质和材料特性和工程(英文)》 2021年第2期194-205,共12页
A quantitative technique was conducted at Rosh Pinah Zinc mine, Namibia with its main purpose to determine airways resistance which is a function of the parameters;roughness of the airways and the friction factor. The... A quantitative technique was conducted at Rosh Pinah Zinc mine, Namibia with its main purpose to determine airways resistance which is a function of the parameters;roughness of the airways and the friction factor. The 32 branch points (<em>i.e.</em> a-ag) that stand for ventilation circuit have been selected. Data collected includes, length and width of airways, air velocity;air density, and roughness of the airways which were used to determine coefficient of frictions, friction factors and airway resistances. A ventilation model was developed. In order to improve the current ventilation model, airways resistance of the mine was determined and simulated in a modified model using VentSim<sup>TM</sup> software. An average total airways resistance of 0.32027 Ns<sup>2</sup>/m<sup>8</sup> has been achieved for Rosh Pinah mine. It should be pointed out that, as the mine advances its production faces deeper, this value would increases suddenly. Simulation revealed that as much as 34.4 m<sup>3</sup>/s of air can be received at the production faces, compared to the measured received amount of 19.3 m<sup>3</sup>/s. Therefore, volumetric efficiency of the mine was improved from 29.3% to 68.3%. It was also noticed that after importing the resistance values into the model together with other parameters, the model was greatly improved and no cause for concern. 展开更多
关键词 Airways Resistance Volumetric Efficiency Friction Factor Simulations
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Performance Analysis and Drying Kinetics of Maize in an AflaSTOP Dryer 认领
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作者 Ernest Owusu-Sekyere George Obeng-Akrofi +1 位作者 Joseph O. Akowuah Dirk Maier 《应用科学(英文)》 2021年第3期327-342,共16页
The performance of an AflaSTOP dryer which utilises biomass energy for drying maize was investigated. The drying behaviour of maize grains in the dryer was also investigated using ten (10) thin-layer mathematical mode... The performance of an AflaSTOP dryer which utilises biomass energy for drying maize was investigated. The drying behaviour of maize grains in the dryer was also investigated using ten (10) thin-layer mathematical models. The models were compared based on coefficient of determination (<em>R</em><sup>2</sup>) and Root Mean Square Error (<em>RMSE</em>) values between experimental and predicted moisture ratios. At an average drying air temperature of 50<span style="white-space:nowrap;">&#176;</span>C and drying air velocity of 2.5 m/s, maize at average moisture content (MC) of 17.5% (wb) was dried to an average MC of 11.5% (wb) in three (3) hours. The drying and thermal efficiency were calculated as 81.1% and 29.6% respectively. Overall, drying took place in the falling rate period. The Logistics model was best to describe the thin-layer drying kinetics of maize in the dryer with <em>R</em><sup>2</sup> value of 0.9902 and <em>RMSE</em> value of 0.04908. 展开更多
关键词 AflaSTOP Dryer Maize Drying Thin Layer Drying Kinetics Drying Efficiency
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Deficient Developmental Planning Leading to Water Conflicts across Political Borders: The Way Forward 认领
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作者 Elias Salameh Nadhir Al-Ansari 《工程(英文)(1947-3931)》 2021年第3期158-172,共15页
In this article, Turkey, Iran and Syria in the Middle East area are taken as examples for deficient planning and development of water resources shared with their downstream countries resulting in severe social, econom... In this article, Turkey, Iran and Syria in the Middle East area are taken as examples for deficient planning and development of water resources shared with their downstream countries resulting in severe social, economic and political percussions to these neighbors. The current situation in the Middle East with wars against terrorism, uprising of population groups, and COVID-19 Pandemic have not allowed the affected countries Jordan, Iraq and Syria to properly react to the assaults of upstream water development and diversions on their fair shares in the transboundary waters. The rivers’ upstream developmental schemes have not taken advantages of recent advanced technological knowhow of water efficient development and use, seemingly because the arising water problems and catastrophes will not affect these upstream countries, but their downstream neighbors. Although, it is by now known that pressurized water conveyance system relative to canals saves 10% - 20% of the transmitted water, and drip and sprinkler irrigation require only 40% - 50% of the water used in surface and furrow irrigation, that is in addition to agricultural production increases when using advanced management strategies. As enhancing policies, tradeoffs between downstream and upstream countries are thought of as a strategic option to improve the water use efficiency in upstream countries in order to help downstream countries in obtaining their fair shares of the transboundary water resources. 展开更多
关键词 Transboundary Water Deficient Planning Water Use Efficiency Middle East TRADEOFFS
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Effects of R134a Saturation Temperature on a Shell and Tube Condenser with the Nanofluid Flow in the Tube Using the Thermal Efficiency and Effectiveness Concepts 认领
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作者 Élcio Nogueira 《纳米科学与工程(英文)》 2021年第1期1-24,共24页
The work’s objective is to analyze the influence of the saturation temperature of the R134a refrigerant on the thermal performance of a shell and tube type condenser, with water and aluminum oxide (Al<sub>2<... The work’s objective is to analyze the influence of the saturation temperature of the R134a refrigerant on the thermal performance of a shell and tube type condenser, with water and aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) nanoparticles flowing into the tube. For analysis, the heat exchanger is subdivided into three regions: subcooled liquid, saturated steam, and superheated steam. The shell and tube heat exchanger assumed as the basis for the study has 36 tubes, with rows of 4 tubes in line and three passes into the tube in each region. The parameters used to analyze the performance are efficiency and effectiveness, through variations of quantities such as saturation temperature, the nanofluid’s mass flow rate, fraction in the nanoparticles’ volume, and the number of passes in the tube in each region of the heat exchanger. The obtained results demonstrate that the efficiency is relatively high in all the analyzed situations. In each saturation temperature, the effectiveness can be increased by introducing fractions of nanoparticles in the water or increasing the number of passes in the tube. 展开更多
关键词 Shell and Tube Condenser R134A NANOFLUID Thermal Efficiency Thermal Effectiveness
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Thermophysical Characterization of Typha’s Concrete for Its Integration into Construction 认领
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作者 Ababacar Sadikh Diaw Harouna Mamadou Bal +3 位作者 Oumar Diallo Mamadou Babacar Ndiaye Mamadou Wade Salif Gaye 《房屋建造与规划研究(英文)》 2021年第1期56-65,共10页
Energy consumption in the building sector is constantly increasing and represents more than 44% in the residential and tertiary sectors in many <span><span style="font-family:Verdana;">countries&... Energy consumption in the building sector is constantly increasing and represents more than 44% in the residential and tertiary sectors in many <span><span style="font-family:Verdana;">countries</span><span style="color:#C45911;"> </span></span><span style="font-family:Verdana;">[1]</span><span></span><span><span></span></span><span style="font-family:Verdana;">. Thus, the building represents a real possibility of energy saving and is the subject of several studies particularly in actual context of experimentation</span><span style="font-family:Verdana;"> with materials based on plant fibers (hemp, flax, millet wastage, etc.). These biobased materials such as typha have shown real interest in the buildings construction due to their light and porous nature. It’s in this context that we were interested in typha australis mixed with classic aggregates (cement, sand, gravel 3/8) to make typha’s concrete. On this concrete, we carried out experimental measurements in order to better understand its contributions in the building. The interesting results obtained show that typha australis, which is an invasive and harmful grass, can be valued and integrated among local building materials in the form of typha’s concrete in order to improve the energy efficiency of buildings.</span> 展开更多
关键词 Typha Australis Bio-Based Materials Thermal Conductivity Thermal Diffusivity Energy Efficiency Asymmetric Hot Plane
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A Comparison Study of Rectifier Designs for 2.45 GHz EM Energy Harvesting 认领
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作者 Sittilin Salleh Mohd Azman Zakariya Razak Mohd Ali Lee 《能源与动力工程(英文)》 2021年第2期81-89,共9页
Energy harvesting is a rapidly growing area in many scientific and engineering-related fields due to the demand for many applications. This paper focuses on the design and simulation of the voltage doubler rectifier c... Energy harvesting is a rapidly growing area in many scientific and engineering-related fields due to the demand for many applications. This paper focuses on the design and simulation of the voltage doubler rectifier circuit at 2.45 GHz operating frequency. The design of a rectifier is optimized based on the use of Schottky diode HSMS 286 B due to its low forward voltage at this frequency. 2 stages of the Schottky diode voltage doublers circuit are designed and simulated in this paper. The shunt capacitor and optimal load resistance are also introduced in the course to reduce signal loss. A multi-stage rectifier is used to produce maximum power conversion from AC to DC. The simulated results present that the maximum output voltage of 6.651 V with an input power of 25 dBm is produced, which presents a maximum power conversion efficiency of 73.13%, which applicable in small device applications. 展开更多
关键词 Energy Harvesting RECTIFIER Schottky Diode Power Conversion Efficiency
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Effects of deep vertical rotary tillage on the grain yield and resource use efficiency of winter wheat in the Huang-Huai-Hai Plain of China 认领 被引量:1
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作者 WU Fen ZHAI Li-chao +6 位作者 XU Ping ZHANG Zheng-bin Elamin Hafiz BAILLO Lemessa Negasa TOLOSA Roy Njoroge KIMOTHO JIA Xiu-ling GUO Hai-qian 《农业科学学报:英文版》 SCIE CAS CSCD 2021年第2期593-605,共13页
Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study car... Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFPN),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFPN and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFPN and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for 展开更多
关键词 winter wheat deep vertical rotary tillage resource use efficiency water use efficiency partial factor productivity of nitrogen
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Promoting Energy Efficiency in the Palestinian Municipalities: A Case Study of Al-Dahriya Municipality 认领
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作者 Husain Alsamamra Iyad Isaila Jawad Shoqeir 《智能电网与可再生能源(英文)》 2021年第2期17-29,共13页
<span style="font-family:Verdana;">Energy demand overall the world increas</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span sty... <span style="font-family:Verdana;">Energy demand overall the world increas</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">es</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> rapidly in various sectors, one of the highest energy consumption sector is the building sector. Installation of PV systems is one of the solutions to cover this demand and will serve in promoting energy efficiency in the Palestinian municipalities in decreasing the electricity bill, and using the saved money in constructing new projects and improving the level of services provided to citizens. In this work, Al-Dahriya municipality has been taken as a case study. The municipality installed 20 KW of photovoltaic panels on the roof of the main building in 2015. The cumulative values for one year after installation the PV system represent a total consumed electricity by the main building was 71,506 kw, while the total generated power by the PV system that transferred to building was 32,664 kw, and 5323 kw exported to the grid with total generated power by PV system was 37,987 kw</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> The participation of energy that produced by the photovoltaic system is 53.12% of the total power demand of the building. The value of generated power varies between the summer months and winter months through the difference of the solar radiation intensity and the number of shinning hours, the largest reading of solar radiation intensity </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">i</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana 展开更多
关键词 Energy Efficiency Photovoltaic Panels Thermal Insulation Al-Dahriya Municipality
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Energy Efficiency of a Simulated Synthetic Natural Gas Combined Cycle (SNGCC) 认领
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作者 Asfaw Gezae Daful Zin Eddine Dadach 《电力能源(英文)》 2021年第3期42-53,共12页
The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation re... The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation results indicate that increasing flue gas recirculation increases the energy consumed by the recirculation compressor and the energy produced by the gas turbine. On the other hand, it decreases the production of energy of the steam turbine and the energy consumed by the pump of the steam cycle. The overall energy efficiency of the SNGCC power plant is highest (41.09%) at a value of 0.20 of the flue gas recirculation. However, the flue gas composition with a FGR ratio of 0.37 is more suitable for effective absorption of carbon dioxide by amine solutions. Based on the low heating value (LHV) of hydrogen, the corresponding overall efficiency of the power plant is 39.18% and the net power output of the plant is 1273 kW for consumption of 97.5 kg/hr. of hydrogen. 展开更多
关键词 Synthetic Natural Gas Combined Cycle SNGCC Energy Efficiency
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Investigation of the Relationship among Water and Crop Production under Bounded Irrigation Conditions 认领
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作者 Tawheed Mohammed Elheesin Shareef Zhongming Ma +1 位作者 Juan Chen Xiaoxia Niu 《水能与环境工程(英文)》 2021年第1期18-35,共18页
Water scarcity is relative and variable concept that can occur at any level of supply and demand. It is also a social construct, which is linked to the intervention in the water cycle and changes over time as a result... Water scarcity is relative and variable concept that can occur at any level of supply and demand. It is also a social construct, which is linked to the intervention in the water cycle and changes over time as a result of natural hydrological change. It is more severe when water acts as a backbone in economic policies, planning and management methods. Water scarcity can be expected to increase with most forms of economic development, but, if properly identified, many of its causes can be expected and avoided or mitigated. However, the limited irrigation management is considered a very important issue in the agricultural scope. Therefore, in this study</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the relationship between water, crop production, photosynthesis, crop transpiration, crop growth, crop yields and water use efficiency have been discussed under limited irrigation conditions. However, the crops have some ability to adapt and resist against limited irrigation. Hence, under high temperate conditions, this is a shortage of water and photosynthesis is decreased with a pore (stoma) restraining. At the same time</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the evapotranspiration reaches to the utmost value and the water use efficiency rises because of optimal monitoring of leaf pore (stoma). Therefore, the modality which is the reduction of the risks and improving industrial control in incomplete irrigation are the chief constraints of providing irrigation water in the future, which leads to increased crop production and ultimately providing a provision of food security. 展开更多
关键词 Freshwater Consumption Insufficient Irrigation Water Use Efficiency Yield Formation
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文章速递哈长城市群环境生态效率及其影响因素分析——基于非期望SBM-Shannon Entropy模型 认领
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作者 尚海潮 付应雄 +2 位作者 陈维国 刘雨佳 于瑛英 《数学的实践与认识》 CSCD 北大核心 2021年第4期264-275,共12页
选取哈长城市群的10个城市作为研究对象,利用2006-2015年的面板数据,测算哈长城市群各城市生态效率并分析影响生态效率的因素.首先运用非期望产出的SBM-Shannon Entropy模型计算各市的生态效率CES得分(Comprehensive Efficiency Score,C... 选取哈长城市群的10个城市作为研究对象,利用2006-2015年的面板数据,测算哈长城市群各城市生态效率并分析影响生态效率的因素.首先运用非期望产出的SBM-Shannon Entropy模型计算各市的生态效率CES得分(Comprehensive Efficiency Score,CES),然后构建Tobit回归模型对CES得分的影响因素进行分析.研究结果表明:哈长城市群2006-2015年生态效率CES得分均值在2011-2014年呈下降趋势,2015年有所回升;其中,大庆市、松原市和绥化市生态效率CES得分均值较高,而牡丹江市、吉林市以及辽源市得分均值在0.5以下.回归分析表明:经济发展水平、地区因素、产业结构、地区对外开放程度、科学技术及企业的管理能力对哈长城市群生态效率CES有显著影响. 展开更多
关键词 生态效率 数据包络分析 非期望SBM-Shannon Entropy模型 综合效率得分(Comprehensive Efficiency Score CES) Tobit回归模型
金融发展对科技创新效率影响的区域收敛性研究 认领
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作者 罗天正 魏成龙 《中国科技论坛》 北大核心 2021年第4期34-43,共10页
本文从金融规模与金融效率两个方面研究了金融发展对科技创新研发和科技创新转化两阶段的效率影响,通过收敛性检验和RIF回归探讨了金融发展在不同创新效率地区的异质性影响。研究结果表明:金融效率和银行信贷规模的增加对提升科技创新... 本文从金融规模与金融效率两个方面研究了金融发展对科技创新研发和科技创新转化两阶段的效率影响,通过收敛性检验和RIF回归探讨了金融发展在不同创新效率地区的异质性影响。研究结果表明:金融效率和银行信贷规模的增加对提升科技创新的研发效率和转化效率均有显著的积极作用,而股票市场规模的扩大对创新研发效率的提升具有激励作用,但对创新转化效率的提高呈现出一定的抑制作用;工业企业的创新转化效率和高技术企业的创新研发效率的收敛性主要来自东、中、西部地区内部差距的缩小,而创新研发效率和高技术企业的创新转化效率的收敛性则由东、中、西部地区内部差距的缩小和三个地区间差距的缩小共同形成。 展开更多
关键词 金融发展 创新效率 创新研发 创新转化 收敛性
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宽波段减反膜实现23.9%效率的平面异质结构钙钛矿太阳能电池 认领
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作者 王亚伦 王卉 +5 位作者 陈梦婷 王胖 毛宇超 韩文娇 王涛 刘丹 《中国科学:材料科学(英文版)》 SCIE EI CAS CSCD 2021年第4期789-797,共9页
虽然钙钛矿太阳能电池效率的发展令人鼓舞,但是由于光反射造成的器件基底界面的光子损失等问题仍然没有解决.光管理是降低反射损失并提高器件效率的有效途径.因此,我们设计了双层减反膜以涂敷在(FAPbI3)x(MAPbBr3)1-x钙钛... 虽然钙钛矿太阳能电池效率的发展令人鼓舞,但是由于光反射造成的器件基底界面的光子损失等问题仍然没有解决.光管理是降低反射损失并提高器件效率的有效途径.因此,我们设计了双层减反膜以涂敷在(FAPbI3)x(MAPbBr3)1-x钙钛矿太阳能电池的玻璃基底外侧,以期达到增加光吸收和提高器件效率的目的.该研究中的减反膜底层由硅聚合物构成,上层由氟代硅聚合物和六甲基二硅氧烷/介孔二氧化硅纳米粒子复合而成.通过精确调控上下层的折射率及厚度,我们在宽波段范围内实现了玻璃基底透过率从最高约90%显著提升到95%.在电池器件的玻璃基底外侧溶液涂膜制备减反膜后,(FAPbI3)x(MAPbBr3)1-x钙钛矿太阳能电池在保持填充因子和开路电压不变的情况下,短路电流和效率分别从25.5 mA cm-2和22.7%提高到26.5 mA cm-2和23.9%.本研究提出了一种简单、高效的通过双层减反膜的光管理提高太阳能电池效率的方法,且此方法可拓展到其他类型太阳能电池体系. 展开更多
关键词 钙钛矿太阳能电池 短路电流 开路电压 填充因子 六甲基二硅氧烷 玻璃基底 减反膜 宽波段
中国省域森林碳汇效率演进分析 认领
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作者 姚仁福 边文燕 +1 位作者 范宏琳 贯君 《林业经济问题》 北大核心 2021年第1期51-59,共9页
基于1999—2018年的林业发展数据,采用森林蓄积量扩展法和DEA-Malmquist法实证分析了中国29个省(市、区)森林碳汇静态效率和动态演进过程。结果表明:1999—2018年中国森林碳汇总量呈增长趋势;从静态方面看,中国碳汇效率总体较低,区域间... 基于1999—2018年的林业发展数据,采用森林蓄积量扩展法和DEA-Malmquist法实证分析了中国29个省(市、区)森林碳汇静态效率和动态演进过程。结果表明:1999—2018年中国森林碳汇总量呈增长趋势;从静态方面看,中国碳汇效率总体较低,区域间差异大,碳汇效率的空间分布与各省(市、区)经济发展水平之间存在一定的反向关联性,纯技术效率是制约综合效率增长的主要因素;从动态方面看,Malmquist生产指数呈U型趋势发展,技术进步指数和技术效率变化指数对Malmquist生产指数的驱动作用不同。因此,相关部门要建立健全林业技术推广体系;提高森林碳汇的科技水平;完善产权激励机制;加快构建碳交易市场;促进林业资源合理配置;加强对森林资源的保护;加快推进集体林权制度改革。 展开更多
关键词 森林碳汇 DEA-Malmquist法 森林蓄积量扩展法 效率
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我国重特大疾病医疗救助效率及其影响因素 认领
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作者 杨浩 何蓓蓓 郑先平 《医学与社会》 北大核心 2021年第2期51-55,共5页
目的:了解全国31个省级行政区2016-2017年的重特大疾病医疗救助效率,分析其影响因素,为进一步完善我国重特大疾病医疗救助制度提供参考。方法:利用DEA-BCC模型测算全国重特大疾病医疗救助效率,用Tobit模型分析我国重特大疾病医疗救助效... 目的:了解全国31个省级行政区2016-2017年的重特大疾病医疗救助效率,分析其影响因素,为进一步完善我国重特大疾病医疗救助制度提供参考。方法:利用DEA-BCC模型测算全国重特大疾病医疗救助效率,用Tobit模型分析我国重特大疾病医疗救助效率的主要影响因素。结果:2016-2017年,我国重特大疾病医疗救助效率均值分别为0.45、0.52,虽呈上升趋势,但整体效率不高。老龄化程度、政府能力、贫困程度、地区人口规模等均对重特大疾病医疗救助效率有不同程度影响。结论:全国平均综合救助效率偏低,东、中、西部地域间整体效率无明显差异,大部分省份救助资源配置有待进一步优化。 展开更多
关键词 重特大疾病医疗救助 效率 影响因素
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物质建构和空间意图双重视野下建筑模块集成化设计研究 认领
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作者 孙鹏 朱雷 《建筑与文化》 2021年第4期239-241,共3页
集成化是对现代建筑模块优化的重要手段之一。文章通过对贝聿铭、阿尔多·凡·艾克以及路易斯·康典型作品的分析,提出集成化在建筑模块中的运用,以优化功能和效率为导向,进而发展出包容性结构、特定空间性质等新的内涵。
关键词 模块 集成 效率 包容性结构 空间性质
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政府投融资产出视角下的城投债风险探析--以安徽省为例 认领
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作者 徐栋 管治华 《青岛农业大学学报:社会科学版》 2021年第1期39-46,共8页
城投债不同于地方政府财政负债,其风险主要取决于债务增长规模与产出增长规模的对比,困此本文运用DEA模型和Malmquist指数测算城投债投资效率和经济增长效率来分祈城投债风险。结果表明:城投债产出绩效水平存在较大提升空间,且呈现较明... 城投债不同于地方政府财政负债,其风险主要取决于债务增长规模与产出增长规模的对比,困此本文运用DEA模型和Malmquist指数测算城投债投资效率和经济增长效率来分祈城投债风险。结果表明:城投债产出绩效水平存在较大提升空间,且呈现较明显的地区差异性,债务管理水平对于债务绩效有显著正面影响。由此,本文提出以下建议:将防范城投债的风险重心落在关注城投债产出;根据城投债产出效率实行不同的风险防范政策;提高城投公司市场化管理水平。 展开更多
关键词 城投债﹔风险 效率 DEA模型 MALMQUIST指数
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