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Search Results: 1 - 10 of 127091 matches for " DongMei Li "
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Optimal Spinning Reserve for Power System with Wind Integrated  [PDF]
Longlong Li, Dongmei Zhao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B193
Abstract:

This paper presents an evolutionary stochastic production simulation to solve the optimal spinning reserve configuration problem in power system with wind integrated. Equivalent load curve is generated with considering the wind power forecasting deviation and generation scheduling of hydropower plant in different water periods. The equivalent load duration curve (ELDC), redrawn from equivalent load curve is the core of stochastic production simulation which focuses on random outage of generator and load fluctuation. The optimal spinning reserve model is established around the reliability index Expected Energy Not Served (ENNS). The optimal scheduling of spinning reserve is reached while the cost of purchasing spinning reserve is equal to the outage loss. At last, results of the optimal spinning reserve model tested in Hainan power grid help reduce the costs of spinning reserve configuration.

An Optimal Dynamic Generation Scheduling for a Wind-Thermal Power System  [PDF]
Xingyu Li, Dongmei Zhao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B194
Abstract:

In this paper, a dynamic generation scheduling model is formulated, aiming at minimizing the costs of power generation and taking into account the constraints of thermal power units and spinning reserve in wind power integrated systems. A dynamic solving method blended with particle swarm optimization algorithm is proposed. In this method, the solution space of the states of unit commitment is created and will be updated when the status of unit commitment changes in a period to meet the spinning reserve demand. The thermal unit operation constrains are inspected in adjacent time intervals to ensure all the states in the solution space effective. The particle swarm algorithm is applied in the procedure to optimize the load distribution of each unit commitment state. A case study in a simulation system is finally given to verify the feasibility and effectiveness of this dynamic optimization algorithm.

Impact of Government and Other Institutions’ Support on Performance of Small and Medium Enterprises in the Agribusiness Sector in Ghana  [PDF]
Evans Brako Ntiamoah, Dongmei Li, Michael Kwamega
American Journal of Industrial and Business Management (AJIBM) , 2016, DOI: 10.4236/ajibm.2016.65052
Abstract: The focus of the study is to examine the impact of government and other Institutions’ support on the performance of small and medium-sized enterprises in agribusiness sector of Ghana. The research adopts quantitative research design. Research evidence was gathered via a questionnaire-based survey of selected agribusiness companies in Ghana. The variables used for study were tested through correlation and regression analysis. The results posit that government support had a statistically significant and direct effect on other institutions’ support and performance of SMEs. The results also indicate that government support had a positive and significant effect on performance of SMEs via the partial mediation effect of other institutions’ support. Conclusions of the study may help academics and managers in implementing the outcome in sequence to enhance other institutions’ support and upgrade performance of SME’s.
Study on Influencing Factors of Rural Insurance Salesman’s Sale Performance
Wenyong Tian,Dongmei Li
International Journal of Business and Management , 2011, DOI: 10.5539/ijbm.v6n5p180
Abstract: Based on the survey data of 111 rural insurance salesmen in Tai Ping Life Insurance Co., ltd, Sichuan branch, this paper has empirically studied on influencing factors of rural insurance salesman’s sale performance by applying multiple ordered and classification logistic model. The result shows that the gender of insurance salesman, working time, levels of position, training goal, training ways, the single premium below 2 000 Yuan, the reward sale and marketing ways of insurance are significant factors. This paper also analyzes the causes of those factors briefly and puts forward relevant suggestions.
An Analysis on Technical Efficiency of Paddy Production in China
Juan Xiao,Dongmei Li
Asian Social Science , 2011, DOI: 10.5539/ass.v7n6p170
Abstract: Paddy is related with China's food security as the main food crop. This paper analyzes the efficiency of paddy production in China using BCC model of DEA method. The results show that the production efficiency of paddy is low and unstable from 1990 to 2008. The inputs of paddy production are unreasonable in many years. The pure technical efficiency is smooth when the scale efficiency isn’t stable, and the scale efficiency is smooth when the pure technical efficiency is unstable. The tendencies of pure technical efficiency and scale efficiency are opposite. Overall, the pure technical efficiency has great impact on paddy production; the effect of scale efficiency is weak.
Analysis and Forecast about China’s Foreign Exchange Reserves Based on Grey System
Shiyun Yang,Dongmei Li
Asian Social Science , 2012, DOI: 10.5539/ass.v8n2p153
Abstract: Based on the Grey correlation analysis, the paper analyzes the influencing factors which affect the foreign exchange reserves in China. It also points out the main connected factors and forecasts the foreign exchange reserves in future by using GM (1, 1) model.
The Empirical Study of Performance Evaluation on the Specialized Cooperative Organizations of Farmers in Sichuan by AHP
Dongmei Li,Man Tian
Journal of Management and Sustainability , 2012, DOI: 10.5539/jms.v2n1p200
Abstract: With the implementation of specialized cooperative organizations of farmers Law of P. R. China in 2007, the specialized cooperative organizations of farmers in China has entered a stage of quick development. But beyond the increasing quantity of cooperatives, whether such development is sustainable or not has become a question that caught attention from both government and academics. This thesis took 142 specialized cooperative organizations of farmers in Sichuan province as object, by using AHP from 5 aspects including governance mechanism, income, development potential, social influence and ecology influence, finally concluded the study on evaluation of performance. The result of the evaluation shows that competitiveness of farmer's cooperatives in Sichuan is still rather weak, operation management is not yet standardized, integral development is inconsistent and development potential of which require further improve.
An Analysis on Total Factor Productivity and Influencing Factors of Soybean in China
Mingming Liu,Dongmei Li
Journal of Agricultural Science , 2010, DOI: 10.5539/jas.v2n2p158
Abstract: To investigate the characteristics of total factor productivity and its influencing factors in china’s soybean. Cobb-Douglas production function model is used in this study. The data is based on the period from 1990 to 2007, and C-D production function is applied twicely. The results of this study indicate that total factor productivity grows at 0.42% annually, the changes fluctuate apparently. Through analysis, the pattern of cultivation, imports and exports policy and technical achievement may contribute to the fluctuation of total factor productivity in China’s soybean. Finally, the study proposes some approaches and policy implications so as to increase the production of soybean.
PCR Detection of the Three Neofabraea Pathogenic Species Responsible for Apple Bull’s Eye Rot  [PDF]
Dongmei Cao, Xin Li, Jijuan Cao, Weifang Wang
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.31009
Abstract:

Apple bull’s eye rot is caused by pathogenic Neofabraea species including N. malicorticis, N. perennans and N. alba. Fruits carrying this fungal quarantine disease are prohibited from entering China. The host plants for the pathogens include several Rosaceae fruits including apple and pear. Disease symptoms and pathogen morphology are often insufficient to determine the identity of the pathogen, particularly at the species level. In the current study, we analyzed the inter-species sequence variations in the β-tublin gene, and designed specific primers to allow PCR amplification of 554 bp fragments from pathogenic Neofabraea species. The PCR products were recovered and sequenced, and Blast search was conducted using the DNA sequences in the Genbank database. The results indicated precise PCR amplification of the target sequences from the host pathogen, which allowed unambiguous identification of the species.

Toxicity and subcellular distribution of cadmium in wheat as affected by dissolved organic acids
Dandan Li,Dongmei Zhou,
Dandan Li
,Dongmei Zhou

环境科学学报(英文版) , 2012,
Abstract: We aim to investigate the effects of humic acid (HA) and citric acid (CA) on the toxicity and subcellular distribution of Cd in wheat. Results show that the toxicity and uptake of Cd decreased with increasing HA. The EC50 values of Cd increased from 3.36 μmol/L to 4.96 and 7.33 μmol/L at 50 and 250 mg/L HA, respectively, but decreased to 1.39 μmol/L in the presence of CA based on free ion activity model (FIAM). HA decreased the relative subcellular distribution of Cd in the heat-denatured proteins (decreased from 54% to 33%) but increased Cd in the heat-stable proteins in root (from 25% to 50%) at 7.61 μmol/L {Cd2+} (free Cd activity), which resulted in decreasing Cd toxicity. However, CA increased Cd toxicity due to the increased internalization of Cd although the relative subcellular distributions of Cd exhibited a decrease in the heat-denatured proteins and increase in the granule fraction compared to the control at high-level Cd. The FIAM could not predict the toxicity of Cd in the presence of organic acids. Alternatively, the internal Cd accumulation and subcellular Cd concentration were better to describe the toxicity of Cd to wheat.
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