Determination of the chemical composition of cement and ratio values of clinker plays an important role in cement plants as part of the optimal process control and product quality evaluation. In the present paper, a l...Determination of the chemical composition of cement and ratio values of clinker plays an important role in cement plants as part of the optimal process control and product quality evaluation. In the present paper, a laboratory laser-induced breakdown spectroscopy(LIBS) apparatus mainly comprising a sealed optical module and an analysis chamber has been designed for possible application in cement plants for on-site quality analysis of cement. Emphasis is placed on the structure and operation of the LIBS apparatus, the sealed optical path, the temperature controlled spectrometer, the sample holder, the proper calibration model established for minimizing the matrix effects, and a correction method proposed for overcoming the ‘drift'obstacle. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The absolute measurement errors presented here for oxides analysis are within 0.5%, while those of ratio values are in the range of 0.02 to 0.05. According to the obtained results, this laboratory LIBS apparatus is capable of performing reliable and accurate, composition and proximate analysis of cement and is suitable for application in cement plants.展开更多
The synchronization of hyperchaotic Chen systems is considered.An adaptive synchronization approach and a cascade adaptive synchronization approach are presented to synchronize a drive system and a response system.By ...The synchronization of hyperchaotic Chen systems is considered.An adaptive synchronization approach and a cascade adaptive synchronization approach are presented to synchronize a drive system and a response system.By utilizing an adaptive controller based on the dynamic compensation mechanism,exact knowledge of the systems is not necessarily required,and the synchronous speed is controllable by tuning the controller parameters.Sufficient conditions for the asymptotic stability of the two synchronization schemes are derived.Numerical simulation results demonstrate that the adaptive synchronization scheme with four control inputs and the cascade adaptive synchronization scheme with only one control signal are effective and feasible in chaos synchronization of hyperchaotic systems.展开更多
The chaos control of uncertain unified chaotic systems is considered. Cascade adaptive control approach with only one control input is presented to stabilize states of the uncertain unified chaotic system at the zero ...The chaos control of uncertain unified chaotic systems is considered. Cascade adaptive control approach with only one control input is presented to stabilize states of the uncertain unified chaotic system at the zero equilibrium point. Since an adaptive controller based on dynamic compensation mechanism is employed,the exact model of the unified chaotic system is not necessarily required. By choosing appropriate controller parameters,chaotic phenomenon can be suppressed and the response speed is tunable. Sufficient condition for the asymptotic stability of the approach is derived. Numerical simulation results confirm that the cascade adaptive control approach with only one control signal is valid in chaos control of uncertain unified chaotic systems.展开更多
The wavelength dependence of laser induced breakdown spectroscopy(LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations.Compared with the 1064 nm wavelength laser a...The wavelength dependence of laser induced breakdown spectroscopy(LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations.Compared with the 1064 nm wavelength laser ablation,the 266 nm wavelength laser ablation has less thermal effects,resulting in a better crater morphology on the coal pellets.Besides,the 266 nm wavelength laser ablation also provides better laser-sample coupling and less plasma shielding,resulting in a higher carbon line intensity and better signal reproducibility.The carbon contents in the bituminous coal samples have better linearity with the line intensities of atomic carbon measured by the 266 nm wavelength than those measured by the 1064 nm wavelength.The partial least square(PLS) model was established for the quantitative analysis of the carbon content in coal samples by LIBS.The results show that both of the 266 nm and 1064 nm wavelengths are capable of achieving good performance for the quantitative analysis of carbon content in coal using the PLS method.展开更多
The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square met...The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor based PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal.展开更多
Laser-induced breakdown spectroscopy(LIBS) is a promising analytical spectroscopy technology based on spectroscopic analysis of the radiation emitted by laser-produced plasma.However, for quantitative analysis by LIBS...Laser-induced breakdown spectroscopy(LIBS) is a promising analytical spectroscopy technology based on spectroscopic analysis of the radiation emitted by laser-produced plasma.However, for quantitative analysis by LIBS, the so-called self-absorption effects on the spectral lines, which affect plasma characteristics, emission line shapes, calibration curves, etc, can no longer be neglected. Hence, understanding and determining the self-absorption effects are of utmost importance to LIBS research. The purpose of this review is to provide a global overview of self-absorption in LIBS on the issues of experimental observations and adverse effects,physical mechanisms, correction or elimination approaches, and utilizations in the past century.We believe that better understanding and effective solving the self-absorption effect will further enhance the development and maturity of LIBS.展开更多
To analyze and control complex networks effectively, this paper puts forward a new kind of scheme, which takes control separately in each area and can achieve the network’s coordinated optimality. The proposed algori...To analyze and control complex networks effectively, this paper puts forward a new kind of scheme, which takes control separately in each area and can achieve the network’s coordinated optimality. The proposed algorithm is made up of two parts: the first part decomposes the network into several independent areas based on community structure and decouples the information flow and control power among areas; the second part selects the center nodes from each area with the help of the control centrality index. As long as the status of center nodes is kept on a satisfactory level in each area, the whole system is under effective control. Finally, the algorithm is applied to power grids, and the simulations prove its effectiveness.展开更多
Wireless sensor networks(WSN) provide an approach to collecting distributed monitoring data and transmiting them to the sink node. This paper proposes a WSN-based multi-hop network infrastructure, to increase network ...Wireless sensor networks(WSN) provide an approach to collecting distributed monitoring data and transmiting them to the sink node. This paper proposes a WSN-based multi-hop network infrastructure, to increase network lifetime by optimizing the routing strategy. First, a network model is established, an operating control strategy is devised, and energy consumption characteristics are analyzed. Second, a fast route-planning algorithm is proposed to obtain the original path that takes into account the remaining energy of communicating nodes and the amount of energy consumed in data transmission. Next, considering the amount of energy consumed by an individual node and the entire network,a criterion function is established to describe node performance and to evaluate data transmission ability. Finally, a route optimizing algorithm is proposed to increase network lifetime by adjusting the transmission route in protection of the weak node(the node with low transmission ability). Simulation and comparison experimental results demonstrate the good performance of the proposed algorithms to increase network lifetime.展开更多
The dispersion and multiple modes characteristics which exist in the propagation of Lamb waves (LW) in metal plates make it extremely hard to analyze and recognize the detection echo signals of defects. As a newly dev...The dispersion and multiple modes characteristics which exist in the propagation of Lamb waves (LW) in metal plates make it extremely hard to analyze and recognize the detection echo signals of defects. As a newly developed time-frequency analysis method in recent years, Hilbert-Huang transform (HHT) is one of the powerful tools to analyze non-stationary signals. The experimental LW detecting system for single aluminum plate is setup in this work, and the LW detecting signals are analyzed by HHT. The overlapped LW detecting signals of different modes are recognized by the means of extracting flight time of intrinsic mode functions (IMFs) after Hilbert transform (HT). The experiment results, agreeing well with the theoretical analysis, indicate that the HHT method can clearly recognize overlapped LW detecting signals of different modes in metal plates, but could hardly recognize that of the same mode. HHT can be an effective method to recognize LW detecting signals of different modes in metal plates.展开更多
Laser-in duced breakdown spectroscopy(LIBS),firstly proposed in 1962 as Brech and Cross[I]successfully detected the plasma emission induced by a ruby laser,has attracted more and more attention in both academia and in...Laser-in duced breakdown spectroscopy(LIBS),firstly proposed in 1962 as Brech and Cross[I]successfully detected the plasma emission induced by a ruby laser,has attracted more and more attention in both academia and industry due to its unique analytical features such as little or no sample preparation,simultaneous multi-elemental analysis,and remote sensing etc[2-4].Restrained from the highcost and poor reliability of instruments back then,the research popularity of LIBS declined quickly after a few years of initial mania of LIBS study.Since the 1990s,benefiting from the significant development of the hardware setups including laser,spectrometer,and ICCD,the'LIBS fever,re-emerged with continuous progress achieved in various applications as well as fundamental studies for the past two decades.In 2004,James D Winefordner,a prestigious an alytical scientist,crowned LIBS as a'future superstar5 for chemical analysis[5],marking the great potential of LIBS.However,on the way of fully commercialization and industrialization,LIBS is facing three big challenges:(1)to improve the quantitative analysis performance,particularly the repeatability and reproducibility performance;(2)to reduce the instrumental cost;(3)to improve the long-term stability and robustness for industrial applications.To finally transform LIBS from'future superstar,to'superstar5,joint effort of worldwide LIBS community is needed[6].展开更多
Laser-induced breakdown spectroscopy(LIBS) is a qualitative and quantitative analytical technique with great potential in the cement industrial analysis. Calibration curve(CC) and support vector regression(SVR) method...Laser-induced breakdown spectroscopy(LIBS) is a qualitative and quantitative analytical technique with great potential in the cement industrial analysis. Calibration curve(CC) and support vector regression(SVR) methods coupled with LIBS technology were applied for the quantification of three types of cement raw meal samples to compare their analytical concentration range and the ability to reduce matrix effects, respectively. To reduce the effects of fluctuations of the pulse-to-pulse, the unstable ablation and improve the reproducibility, all of the analysis line intensities were normalized on a per-detector basis. The prediction results of the elements of interest in the three types of samples, Ca, Si, Fe, Al, Mg, Na, K and Ti, were compared with the results of the wet chemical analysis. The average relative error(ARE),relative standard deviation(RSD) and root mean squared error of prediction(RMSEP) were employed to investigate and evaluate the prediction accuracy and stability of the two prediction methods. The maximum average ARE of the CC and SVR methods is 34.62% instead of 6.13%,RSD is 40.89% instead of 7.60% and RMSEP is 1.34% instead of 0.43%. The results show that SVR method can accurately analyze samples within a wider concentration range and reduce the matrix effects, and LIBS coupled with it for a rapid, stable and accurate quantification of different types of cement raw meal samples is promising.展开更多
For the implementation of power market in China,medium-and Iong-term security checks are essential for bilateral transactions,of which the electricity quantity that constitutes the generation feasible region(GFR)is th...For the implementation of power market in China,medium-and Iong-term security checks are essential for bilateral transactions,of which the electricity quantity that constitutes the generation feasible region(GFR)is the target.However,uncertainties from load forecasting errors and transmission contingencies are threats to medium-and Iong-term electricity tradi ng in terms of their in flue nces on the GFR.In this paper,we prese nt a graphic distortio n pattern in a typical threegenerator system using the Monte Carlo method and projection theory based on security constrained economic dispatch.The underlying potential risk to GFR from uncertainties is clearly visualized,and their impact characteristics are discussed.A case study on detailed GFR distortion was included to dem on strate the effectiveness of this visualization model.The result implies that a small uncertainty could distort the GFR to a remarkable extent and that different line-contingency precipitates disparate the GFR distortion patterns,thereby eliciting great emphasis on load forecasting and line reliability in electricity transacti ons.展开更多
Coordinated vehicle-to-grid(V2G)control strategies can sustain essential loads of an energy system during islanding,thereby increasing resilience.In this context,this paper investigates the resilience enhancement bene...Coordinated vehicle-to-grid(V2G)control strategies can sustain essential loads of an energy system during islanding,thereby increasing resilience.In this context,this paper investigates the resilience enhancement benefits of smart V2G control,the value of electric vehicle(EV)owner cooperation on system resilience,as well as the complementary effects of PV and EV interaction in an urban multi-energy microgrid(MEMG).By using a rolling horizon approach to optimize day-ahead operation of the MEMG and subsequently dispatching EVs,uncertainties in outage start time,EV arrival/departure times,and initial state of charge(SOC)are mitigated.Results show that smart V2G control can provide a substantial essential load curtailment reduction compared to a non-EV scenario,meanwhile,non-coordinated grid-to-vehicle(G2V)operation was shown to slightly burden the system with a slight increase in non-essential load curtailment.Investigations into the influence of EV cooperation on resilience showed that a high percentage of system-prioritized(SP)EVs could help greatly further reduce essential load curtailment compared to individual-prioritized(IP)EVs.Finally,the complementary benefits of smart V2G control and PV were demonstrated,showing a reduction in both PV and essential load curtailments with increasing numbers of EVs.Overall,the application of smart V2G control,especially with cooperation of EV owners,can drive significant resilience enhancement during islanding,while further benefits can be obtained through having a sufficient number of EVs to utilize high PV penetration.展开更多
As one of promising clean and low-emission energy, wind power is being rapidly developed in China.However, it faces serious problem of wind curtailment,particularly in northeast China, where combined heat and power(CH...As one of promising clean and low-emission energy, wind power is being rapidly developed in China.However, it faces serious problem of wind curtailment,particularly in northeast China, where combined heat and power(CHP) units cover a large proportion of the district heat supply. Due to the inherent strong coupling between the power and the heat load, the operational flexibility of CHP units is severely restricted in winter to meet the heat supply demand, which imparts considerable stress on the wind power connection to the grid. To promote the integration of wind power and enhance the flexibility of CHP units, this paper presented a method of heat and power load dispatching by exploring the energy storage ability of electric heating boilers and district heating systems. The optimization results indicate that the proposed method can integrate additional wind power into the grid and reduce the coal consumption of CHP units over the optimized period. Furthermore, the thermal inertia of a district heating system is found to contribute more to the reduction of coal consumption, whereas the electric heating boilers contribute to lower wind curtailment.展开更多
Sequence operation theory (SOT) is a powerful tool for solving complex probabil-istic problems in power system. However, the basic single dimension SOT cannot satisfy the requirement of multi-state and multi-attribute...Sequence operation theory (SOT) is a powerful tool for solving complex probabil-istic problems in power system. However, the basic single dimension SOT cannot satisfy the requirement of multi-state and multi-attribute analysis, which is often the case in actual power system practice. To address this problem, multidimensional sequence operation theory (MSOT) is developed. On the basis of previous research, this paper first categorizes the situations by the number of state variables and the number of attribute values, and defines the multidimensional sequence for single state variable and multiple attribute values, as well as the multidimensional se-quence for multiple state variables and multiple attribute values. Corresponding to those definitions, four types of operations between two discrete multidimensional sequences are derived respectively. Therefore, the sequence is extended from sin-gle dimensional to multidimensional, establishing an integrated theory of multidi-mensional sequence operation. In particular, the basic single dimension SOT can be viewed as a special case of MSOT with only one state variable and one attribute value. Finally, the paper demonstrates the effectiveness of MSOT through an ex-ample of risk evaluation in power system generation scheduling.展开更多
The narrow definition of the digital power system (DPS) is proposed. The architec- ture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control syste...The narrow definition of the digital power system (DPS) is proposed. The architec- ture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control system and data sharing platform. The successful construction of the DPS can greatly improve the performances of power system operating and dispatching, which mainly reflect a fundamental in- crease of the ability of avoiding catastrophes resulting from blackouts of power supply, a significant improvement of economic efficiency of power system opera- tion, and an improvement of decision efficiency of power system developing. The DPS describes a vision of the development of power system and the way to achieve this vision. At the same time, the paper also proposes the principles of the design and implementation of the DPS.展开更多
基金supported by National Natural Science Foundation of China(Nos.61127017,61378047,61205216,61178009,61108030,61475093,and 61275213)the National Key Technology R&D Program of China(No.2013BAC14B01)+2 种基金the 973 Program of China(No.2012CB921603)the Shanxi Natural Science Foundation,China(Nos.2013021004-1,2012021022-1)the Shanxi Scholarship Council of China(Nos.2013-011 and 2013-01)
文摘Determination of the chemical composition of cement and ratio values of clinker plays an important role in cement plants as part of the optimal process control and product quality evaluation. In the present paper, a laboratory laser-induced breakdown spectroscopy(LIBS) apparatus mainly comprising a sealed optical module and an analysis chamber has been designed for possible application in cement plants for on-site quality analysis of cement. Emphasis is placed on the structure and operation of the LIBS apparatus, the sealed optical path, the temperature controlled spectrometer, the sample holder, the proper calibration model established for minimizing the matrix effects, and a correction method proposed for overcoming the ‘drift'obstacle. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The absolute measurement errors presented here for oxides analysis are within 0.5%, while those of ratio values are in the range of 0.02 to 0.05. According to the obtained results, this laboratory LIBS apparatus is capable of performing reliable and accurate, composition and proximate analysis of cement and is suitable for application in cement plants.
基金Project supported by the National Basic Research Program of China (Grant No. 2007CB210106)
文摘The synchronization of hyperchaotic Chen systems is considered.An adaptive synchronization approach and a cascade adaptive synchronization approach are presented to synchronize a drive system and a response system.By utilizing an adaptive controller based on the dynamic compensation mechanism,exact knowledge of the systems is not necessarily required,and the synchronous speed is controllable by tuning the controller parameters.Sufficient conditions for the asymptotic stability of the two synchronization schemes are derived.Numerical simulation results demonstrate that the adaptive synchronization scheme with four control inputs and the cascade adaptive synchronization scheme with only one control signal are effective and feasible in chaos synchronization of hyperchaotic systems.
基金supported by the National Basic Research Program of China (Grant No.2007CB210106)
文摘The chaos control of uncertain unified chaotic systems is considered. Cascade adaptive control approach with only one control input is presented to stabilize states of the uncertain unified chaotic system at the zero equilibrium point. Since an adaptive controller based on dynamic compensation mechanism is employed,the exact model of the unified chaotic system is not necessarily required. By choosing appropriate controller parameters,chaotic phenomenon can be suppressed and the response speed is tunable. Sufficient condition for the asymptotic stability of the approach is derived. Numerical simulation results confirm that the cascade adaptive control approach with only one control signal is valid in chaos control of uncertain unified chaotic systems.
基金supported by National Natural Science Foundation of China(No.51276100)National Basic Research Program of China(973 Program)(No.2013CB228501)
文摘The wavelength dependence of laser induced breakdown spectroscopy(LIBS) in the analysis of the carbon contents of coal was studied using 266 nm and 1064 nm laser radiations.Compared with the 1064 nm wavelength laser ablation,the 266 nm wavelength laser ablation has less thermal effects,resulting in a better crater morphology on the coal pellets.Besides,the 266 nm wavelength laser ablation also provides better laser-sample coupling and less plasma shielding,resulting in a higher carbon line intensity and better signal reproducibility.The carbon contents in the bituminous coal samples have better linearity with the line intensities of atomic carbon measured by the 266 nm wavelength than those measured by the 1064 nm wavelength.The partial least square(PLS) model was established for the quantitative analysis of the carbon content in coal samples by LIBS.The results show that both of the 266 nm and 1064 nm wavelengths are capable of achieving good performance for the quantitative analysis of carbon content in coal using the PLS method.
基金supported by National Natural Science Foundation of China(No.51276100)the National Basic Research Program of China(973 Program)(No.2013CB228501)the financial funding from the U.S.Department of Energy,Office of Basic Energy Sciences,Chemical Science Division at Lawrence Berkeley National Laboratory(No.2013CB228501)
文摘The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor based PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal.
基金supported by National Key R&D Program of China (2017YFA0304203)Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (IRT13076)+1 种基金National Natural Science Foundation of China (NSFC) (Nos. 61475093, 61875108, 61775125)Major Special Science and Technology Projects in Shanxi Province (MD2016-01)
文摘Laser-induced breakdown spectroscopy(LIBS) is a promising analytical spectroscopy technology based on spectroscopic analysis of the radiation emitted by laser-produced plasma.However, for quantitative analysis by LIBS, the so-called self-absorption effects on the spectral lines, which affect plasma characteristics, emission line shapes, calibration curves, etc, can no longer be neglected. Hence, understanding and determining the self-absorption effects are of utmost importance to LIBS research. The purpose of this review is to provide a global overview of self-absorption in LIBS on the issues of experimental observations and adverse effects,physical mechanisms, correction or elimination approaches, and utilizations in the past century.We believe that better understanding and effective solving the self-absorption effect will further enhance the development and maturity of LIBS.
基金the National Science Foundation of China (No.50525721, 50595411)the National Basic Research Program of China(No.G2004CB217902)
文摘To analyze and control complex networks effectively, this paper puts forward a new kind of scheme, which takes control separately in each area and can achieve the network’s coordinated optimality. The proposed algorithm is made up of two parts: the first part decomposes the network into several independent areas based on community structure and decouples the information flow and control power among areas; the second part selects the center nodes from each area with the help of the control centrality index. As long as the status of center nodes is kept on a satisfactory level in each area, the whole system is under effective control. Finally, the algorithm is applied to power grids, and the simulations prove its effectiveness.
基金supported by the National Natural Science Foundation of China(61571068)the Innovative Research Projects of Colleges and Universities in Chongqing(12A19369)
文摘Wireless sensor networks(WSN) provide an approach to collecting distributed monitoring data and transmiting them to the sink node. This paper proposes a WSN-based multi-hop network infrastructure, to increase network lifetime by optimizing the routing strategy. First, a network model is established, an operating control strategy is devised, and energy consumption characteristics are analyzed. Second, a fast route-planning algorithm is proposed to obtain the original path that takes into account the remaining energy of communicating nodes and the amount of energy consumed in data transmission. Next, considering the amount of energy consumed by an individual node and the entire network,a criterion function is established to describe node performance and to evaluate data transmission ability. Finally, a route optimizing algorithm is proposed to increase network lifetime by adjusting the transmission route in protection of the weak node(the node with low transmission ability). Simulation and comparison experimental results demonstrate the good performance of the proposed algorithms to increase network lifetime.
文摘The dispersion and multiple modes characteristics which exist in the propagation of Lamb waves (LW) in metal plates make it extremely hard to analyze and recognize the detection echo signals of defects. As a newly developed time-frequency analysis method in recent years, Hilbert-Huang transform (HHT) is one of the powerful tools to analyze non-stationary signals. The experimental LW detecting system for single aluminum plate is setup in this work, and the LW detecting signals are analyzed by HHT. The overlapped LW detecting signals of different modes are recognized by the means of extracting flight time of intrinsic mode functions (IMFs) after Hilbert transform (HT). The experiment results, agreeing well with the theoretical analysis, indicate that the HHT method can clearly recognize overlapped LW detecting signals of different modes in metal plates, but could hardly recognize that of the same mode. HHT can be an effective method to recognize LW detecting signals of different modes in metal plates.
文摘Laser-in duced breakdown spectroscopy(LIBS),firstly proposed in 1962 as Brech and Cross[I]successfully detected the plasma emission induced by a ruby laser,has attracted more and more attention in both academia and industry due to its unique analytical features such as little or no sample preparation,simultaneous multi-elemental analysis,and remote sensing etc[2-4].Restrained from the highcost and poor reliability of instruments back then,the research popularity of LIBS declined quickly after a few years of initial mania of LIBS study.Since the 1990s,benefiting from the significant development of the hardware setups including laser,spectrometer,and ICCD,the'LIBS fever,re-emerged with continuous progress achieved in various applications as well as fundamental studies for the past two decades.In 2004,James D Winefordner,a prestigious an alytical scientist,crowned LIBS as a'future superstar5 for chemical analysis[5],marking the great potential of LIBS.However,on the way of fully commercialization and industrialization,LIBS is facing three big challenges:(1)to improve the quantitative analysis performance,particularly the repeatability and reproducibility performance;(2)to reduce the instrumental cost;(3)to improve the long-term stability and robustness for industrial applications.To finally transform LIBS from'future superstar,to'superstar5,joint effort of worldwide LIBS community is needed[6].
基金supported by National Natural Science Foundation of China (Grant Nos. 61505223, 41775128)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. Y03RC21124)+1 种基金the External Cooperation Program of Chinese Academy of Sciences (Grant No. GJHZ1726)the project of China State Key Lab. of Power System (Grant Nos. SKLD18KM11, SKLD18M12)
文摘Laser-induced breakdown spectroscopy(LIBS) is a qualitative and quantitative analytical technique with great potential in the cement industrial analysis. Calibration curve(CC) and support vector regression(SVR) methods coupled with LIBS technology were applied for the quantification of three types of cement raw meal samples to compare their analytical concentration range and the ability to reduce matrix effects, respectively. To reduce the effects of fluctuations of the pulse-to-pulse, the unstable ablation and improve the reproducibility, all of the analysis line intensities were normalized on a per-detector basis. The prediction results of the elements of interest in the three types of samples, Ca, Si, Fe, Al, Mg, Na, K and Ti, were compared with the results of the wet chemical analysis. The average relative error(ARE),relative standard deviation(RSD) and root mean squared error of prediction(RMSEP) were employed to investigate and evaluate the prediction accuracy and stability of the two prediction methods. The maximum average ARE of the CC and SVR methods is 34.62% instead of 6.13%,RSD is 40.89% instead of 7.60% and RMSEP is 1.34% instead of 0.43%. The results show that SVR method can accurately analyze samples within a wider concentration range and reduce the matrix effects, and LIBS coupled with it for a rapid, stable and accurate quantification of different types of cement raw meal samples is promising.
基金Supported by the Scientific Research Foundation of Xi’an University of Technology under Grant No 101-451115007the National Natural Science Foundation of China under Grant No 51174161the Pivot Innovation Team of Shaanxi Electric Materials and Infiltration Technique under Grant No 2012KCT-25
基金the National Key R&D Program of China under Grant No.2020YFB0905900in part by the State Grid Corporation of China project“Research on inter-provincial price coupling mechanism of national unified electricity spot market”.
文摘For the implementation of power market in China,medium-and Iong-term security checks are essential for bilateral transactions,of which the electricity quantity that constitutes the generation feasible region(GFR)is the target.However,uncertainties from load forecasting errors and transmission contingencies are threats to medium-and Iong-term electricity tradi ng in terms of their in flue nces on the GFR.In this paper,we prese nt a graphic distortio n pattern in a typical threegenerator system using the Monte Carlo method and projection theory based on security constrained economic dispatch.The underlying potential risk to GFR from uncertainties is clearly visualized,and their impact characteristics are discussed.A case study on detailed GFR distortion was included to dem on strate the effectiveness of this visualization model.The result implies that a small uncertainty could distort the GFR to a remarkable extent and that different line-contingency precipitates disparate the GFR distortion patterns,thereby eliciting great emphasis on load forecasting and line reliability in electricity transacti ons.
基金supported by the UK Engineering and Physical Sciences Research Council (EP/L015471/1EP/R045518/1).
文摘Coordinated vehicle-to-grid(V2G)control strategies can sustain essential loads of an energy system during islanding,thereby increasing resilience.In this context,this paper investigates the resilience enhancement benefits of smart V2G control,the value of electric vehicle(EV)owner cooperation on system resilience,as well as the complementary effects of PV and EV interaction in an urban multi-energy microgrid(MEMG).By using a rolling horizon approach to optimize day-ahead operation of the MEMG and subsequently dispatching EVs,uncertainties in outage start time,EV arrival/departure times,and initial state of charge(SOC)are mitigated.Results show that smart V2G control can provide a substantial essential load curtailment reduction compared to a non-EV scenario,meanwhile,non-coordinated grid-to-vehicle(G2V)operation was shown to slightly burden the system with a slight increase in non-essential load curtailment.Investigations into the influence of EV cooperation on resilience showed that a high percentage of system-prioritized(SP)EVs could help greatly further reduce essential load curtailment compared to individual-prioritized(IP)EVs.Finally,the complementary benefits of smart V2G control and PV were demonstrated,showing a reduction in both PV and essential load curtailments with increasing numbers of EVs.Overall,the application of smart V2G control,especially with cooperation of EV owners,can drive significant resilience enhancement during islanding,while further benefits can be obtained through having a sufficient number of EVs to utilize high PV penetration.
基金supported by National Key Tech-nology R&D Program(No.2015BAA01B01)State Grid Corporation of China
文摘As one of promising clean and low-emission energy, wind power is being rapidly developed in China.However, it faces serious problem of wind curtailment,particularly in northeast China, where combined heat and power(CHP) units cover a large proportion of the district heat supply. Due to the inherent strong coupling between the power and the heat load, the operational flexibility of CHP units is severely restricted in winter to meet the heat supply demand, which imparts considerable stress on the wind power connection to the grid. To promote the integration of wind power and enhance the flexibility of CHP units, this paper presented a method of heat and power load dispatching by exploring the energy storage ability of electric heating boilers and district heating systems. The optimization results indicate that the proposed method can integrate additional wind power into the grid and reduce the coal consumption of CHP units over the optimized period. Furthermore, the thermal inertia of a district heating system is found to contribute more to the reduction of coal consumption, whereas the electric heating boilers contribute to lower wind curtailment.
基金Supported by the National Natural Science Foundation of China (Grant No. 50777031)Program for New Century Excellent Talents in University (Grant No. NCET-07-0484)the Fok Ying-Tong Education Foundation (Grant No. 104020)
文摘Sequence operation theory (SOT) is a powerful tool for solving complex probabil-istic problems in power system. However, the basic single dimension SOT cannot satisfy the requirement of multi-state and multi-attribute analysis, which is often the case in actual power system practice. To address this problem, multidimensional sequence operation theory (MSOT) is developed. On the basis of previous research, this paper first categorizes the situations by the number of state variables and the number of attribute values, and defines the multidimensional sequence for single state variable and multiple attribute values, as well as the multidimensional se-quence for multiple state variables and multiple attribute values. Corresponding to those definitions, four types of operations between two discrete multidimensional sequences are derived respectively. Therefore, the sequence is extended from sin-gle dimensional to multidimensional, establishing an integrated theory of multidi-mensional sequence operation. In particular, the basic single dimension SOT can be viewed as a special case of MSOT with only one state variable and one attribute value. Finally, the paper demonstrates the effectiveness of MSOT through an ex-ample of risk evaluation in power system generation scheduling.
基金the National Natural Science Foundation of China (Grant Nos. 50595411 and 50377018) the Major State Basic Research De-velopment Program (973 Program) (Grant No. 2004CB217903)
文摘The narrow definition of the digital power system (DPS) is proposed. The architec- ture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control system and data sharing platform. The successful construction of the DPS can greatly improve the performances of power system operating and dispatching, which mainly reflect a fundamental in- crease of the ability of avoiding catastrophes resulting from blackouts of power supply, a significant improvement of economic efficiency of power system opera- tion, and an improvement of decision efficiency of power system developing. The DPS describes a vision of the development of power system and the way to achieve this vision. At the same time, the paper also proposes the principles of the design and implementation of the DPS.
