Driven by the desire of a low-carbon society,the penetration level of renewable generation in the power grid of China will still grow fast in the near future.As the synchronised generators whose output is controllable...Driven by the desire of a low-carbon society,the penetration level of renewable generation in the power grid of China will still grow fast in the near future.As the synchronised generators whose output is controllable are gradually replaced by volatile energy resources,energy storage is expected to play a vital role in regulation services and flexibility provision.Because the capital cost of energy storage is still relatively high,it is important to assess the value or demand of energy storage before making an investment decision.This paper presents two representative mathematical tools to achieve this target in a geometric fashion.The first one is the multi-parametric programming method.It depicts the reduced cost by deploying energy storage through post-optimal value function,which is easy to visualise or can be embedded in high-level optimisation problems such as storage sizing.The second one is a polyhedral projection method.It represents all feasible power-energy capacity pairs of a storage unit to achieve a certain target.The above methods remove the need of repeatedly solving a large number of problems with varying capacity parameters.Simple examples are given for illustration,and the presented methods can also directly handle problems with complex models and constraints.展开更多
In order to improve the anaerobic digestion efficiency of waste activated sludge（WAS）,a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic...In order to improve the anaerobic digestion efficiency of waste activated sludge（WAS）,a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic matters.In this paper,a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures.The magnitude of the DC voltage was 4 k V at both negative and positive polarities.The changes in the soluble chemical oxygen demand,phosphorus and nitrogen content,and p H value within the WAS were utilized to estimate the pretreatment performance of the DC corona.It was found that with increasing treatment time,the pretreatment efficiency tends to be reduced.With increased temperature,the pretreatment efficiency appears to be better.It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure,which is dependent upon the treatment time and the temperature.展开更多
Increasing popularity of spectrum-based services brings the striking contradictions between the limited spectrum resource and its increasing demands.This paper puts forward an approach to forecast the future spectrum ...Increasing popularity of spectrum-based services brings the striking contradictions between the limited spectrum resource and its increasing demands.This paper puts forward an approach to forecast the future spectrum demand and its economic value,so as to offer a scientific basis for spectrum regulators to resolve this contradiction effectively and make a long-term spectrum-use plan.Specifically,this paper analyzes the driving factors of spectrum demand firstly,based on which a forecasting model is constructed to predict the spectrum demand and its deficit/surplus in the next few years.Then,a forecasting model to measure the economic value of spectrum is proposed based on marginal opportunity cost theory,and the indifference curve is introduced to show the economic value generated by additional spectrum.Additionally,an empirical study is conducted to forecast the spectrum demand and its economic value for China in the next 10 years according to the proposed method.The results of this study show that spectrum deficit is a trend in future and releasing additional spectrum will bring China huge economic benefits.展开更多
基金supported by the National Key Research and Development Programme of China(2021YFB2400701).
文摘Driven by the desire of a low-carbon society,the penetration level of renewable generation in the power grid of China will still grow fast in the near future.As the synchronised generators whose output is controllable are gradually replaced by volatile energy resources,energy storage is expected to play a vital role in regulation services and flexibility provision.Because the capital cost of energy storage is still relatively high,it is important to assess the value or demand of energy storage before making an investment decision.This paper presents two representative mathematical tools to achieve this target in a geometric fashion.The first one is the multi-parametric programming method.It depicts the reduced cost by deploying energy storage through post-optimal value function,which is easy to visualise or can be embedded in high-level optimisation problems such as storage sizing.The second one is a polyhedral projection method.It represents all feasible power-energy capacity pairs of a storage unit to achieve a certain target.The above methods remove the need of repeatedly solving a large number of problems with varying capacity parameters.Simple examples are given for illustration,and the presented methods can also directly handle problems with complex models and constraints.
基金financially supported by National Natural Science Foundation of China(Grant No.51677127)
文摘In order to improve the anaerobic digestion efficiency of waste activated sludge（WAS）,a pretreatment procedure should be carried out so as to disrupt the microbial cell structure,thus releasing intracellular organic matters.In this paper,a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures.The magnitude of the DC voltage was 4 k V at both negative and positive polarities.The changes in the soluble chemical oxygen demand,phosphorus and nitrogen content,and p H value within the WAS were utilized to estimate the pretreatment performance of the DC corona.It was found that with increasing treatment time,the pretreatment efficiency tends to be reduced.With increased temperature,the pretreatment efficiency appears to be better.It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure,which is dependent upon the treatment time and the temperature.
基金supported by the project: Assessment of economic and social impact of Mobile Broadband in China,which is entrusted by GSM Association in 2011
文摘Increasing popularity of spectrum-based services brings the striking contradictions between the limited spectrum resource and its increasing demands.This paper puts forward an approach to forecast the future spectrum demand and its economic value,so as to offer a scientific basis for spectrum regulators to resolve this contradiction effectively and make a long-term spectrum-use plan.Specifically,this paper analyzes the driving factors of spectrum demand firstly,based on which a forecasting model is constructed to predict the spectrum demand and its deficit/surplus in the next few years.Then,a forecasting model to measure the economic value of spectrum is proposed based on marginal opportunity cost theory,and the indifference curve is introduced to show the economic value generated by additional spectrum.Additionally,an empirical study is conducted to forecast the spectrum demand and its economic value for China in the next 10 years according to the proposed method.The results of this study show that spectrum deficit is a trend in future and releasing additional spectrum will bring China huge economic benefits.
