increasing penetration of renewable energy sources with a wide range of operating conditions causing power system uncertainties, conventional controllers are incapable of providing proper performance to keep the syste...increasing penetration of renewable energy sources with a wide range of operating conditions causing power system uncertainties, conventional controllers are incapable of providing proper performance to keep the system stable. However, controllable or dispatchable loads such as electric vehicles （EVs） and heat pumps （HPs） can be utilized for supplementary frequency control. This paper shows the ability of plug-in hybrid EVs, HPs, and batteries （BTs） to contribute in the frequency control of an isolated power system. Moreover, we propose a new online intelligent approach by using a coefficient diagram method （CDM） to enhance the system performance and robustness against uncertainties. The performance of the proposed intelligent CDM control has been compared with the proportional-integral （PI） controller and the superiority of the proposed scheme has been verified in Matiab/Simulink programs.展开更多
In this study,geochemical anomaly separation was carried out with methods based on the distribution model,which includes probability diagram(MPD),fractal(concentration-area technique),and U-statistic methods.The main ...In this study,geochemical anomaly separation was carried out with methods based on the distribution model,which includes probability diagram(MPD),fractal(concentration-area technique),and U-statistic methods.The main objective is to evaluate the efficiency and accuracy of the methods in separation of anomalies on the shear zone gold mineralization.For this purpose,samples were taken from the secondary lithogeochemical environment(stream sediment samples)on the gold mineralization in Saqqez,NW of Iran.Interpretation of the histograms and diagrams showed that the MPD is capable of identifying two phases of mineralization.The fractal method could separate only one phase of change based on the fractal dimension with high concentration areas of the Au element.The spatial analysis showed two mixed subpopulations after U=0 and another subpopulation with very high U values.The MPD analysis followed spatial analysis,which shows the detail of the variations.Six mineralized zones detected from local geochemical exploration results were used for validating the methods mentioned above.The MPD method was able to identify the anomalous areas higher than 90%,whereas the two other methods identified 60%(maximum)of the anomalous areas.The raw data without any estimation for the concentration was used by the MPD method using aminimum of calculations to determine the threshold values.Therefore,the MPD method is more robust than the other methods.The spatial analysis identified the detail soft hegeological and mineralization events that were affected in the study area.MPD is recommended as the best,and the spatial U-analysis is the next reliable method to be used.The fractal method could show more detail of the events and variations in the area with asymmetrical grid net and a higher density of sampling or at the detailed exploration stage.展开更多
Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscilla...Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscillations, caused by weak but long-lasting and frequency-stable influences, create the conditions for ultrasonic wave’s generation in the layers, which are capable of destroying thickened oil membranes in reservoir cracks. For fractured-porous reservoirs in the process of exploitation by the method of water high-pressure oil displacement, the possibility of intensifying ultrasonic vibrations can have an important technological significance. Even a very weak ultrasound can destroy, over a long period of time, the viscous oil membranes formed in the cracks between the blocks, which can be the reason for lowering the permeability of the layers and increasing the oil recovery. To describe these effects, it is necessary to consider the wave process in a hierarchically blocky environment and theoretically simulate the mechanism of the appearance of self-oscillations under the action of relaxation shear stresses. For the analysis of seism acoustic response in time on fixed intervals along the borehole an algorithm of phase diagrams of the state of many-phase medium is suggested.展开更多
Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the si...Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the simplex method. This method is suitable for the calculation of the stable equilibria in complicated systems. For example. calculated results in comparison with experimental results as well as the prediction of new systems were shown in the present work展开更多
A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO...A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.The solubility of oxygen in Mn and the composition of the interface between MnO and Mn were determined.Partial phase diagram of Mn-MnO system were constructed according to pres- ent experimental results.展开更多
Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation...Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation,along with the construction of a high-precision mobile gravity network covering Chinese mainland,have positioned temporal gravity variations(GVs)as an important tool for clarifying the signal characteristics and dynamic mechanisms of crustal sources.Reportedly,crustal mass transfer,which is affected by stress state and structural environment,alters the characteristics of the regional gravity field,thus serving as an indicator for locations of moderate to strong earthquakes and a seismology-independent predictor for regions at risk for strong earthquakes.Therefore,quantitatively tracking time-varying gravity is of paramount importance to enhance the effectiveness of earthquake prediction.In this study,we divided the areas effectively covered by the terrestrial mobile gravity network in the Sichuan-Yunnan region into small grids based on the latest observational data(since 2018)from the network.Next,we calculated the 1-and 3-year GVs and gravity gradient indicators(amplitude of analytic signal,AAS;total horizontal derivative,THD;and amplitude of vertical gradient,AVG)to quantitatively characterize variations in regional time-varying gravity field.Next,we assessed the effectiveness of gravity field variations in predicting earthquakes in the Sichuan-Yunnan region using Molchan diagrams constructed for gravity signals of 13 earthquakes(M≥5.0;occurred between 2021 and 2024)within the terrestrial mobile gravity network.The results reveal a certain correspondence between gravity field variations and the locations of moderate and strong earthquakes in the Sichuan-Yunnan region.Furthermore,the 3-year AAS and AVG outperform the 3-year THD in predicting subsequent seismic events.Notably,the AAS and AVG showed large probability gains prior to the M_(S)6.8 Luding earthquake,indicating their potential for earthquake prediction.展开更多
文摘increasing penetration of renewable energy sources with a wide range of operating conditions causing power system uncertainties, conventional controllers are incapable of providing proper performance to keep the system stable. However, controllable or dispatchable loads such as electric vehicles （EVs） and heat pumps （HPs） can be utilized for supplementary frequency control. This paper shows the ability of plug-in hybrid EVs, HPs, and batteries （BTs） to contribute in the frequency control of an isolated power system. Moreover, we propose a new online intelligent approach by using a coefficient diagram method （CDM） to enhance the system performance and robustness against uncertainties. The performance of the proposed intelligent CDM control has been compared with the proportional-integral （PI） controller and the superiority of the proposed scheme has been verified in Matiab/Simulink programs.
文摘In this study,geochemical anomaly separation was carried out with methods based on the distribution model,which includes probability diagram(MPD),fractal(concentration-area technique),and U-statistic methods.The main objective is to evaluate the efficiency and accuracy of the methods in separation of anomalies on the shear zone gold mineralization.For this purpose,samples were taken from the secondary lithogeochemical environment(stream sediment samples)on the gold mineralization in Saqqez,NW of Iran.Interpretation of the histograms and diagrams showed that the MPD is capable of identifying two phases of mineralization.The fractal method could separate only one phase of change based on the fractal dimension with high concentration areas of the Au element.The spatial analysis showed two mixed subpopulations after U=0 and another subpopulation with very high U values.The MPD analysis followed spatial analysis,which shows the detail of the variations.Six mineralized zones detected from local geochemical exploration results were used for validating the methods mentioned above.The MPD method was able to identify the anomalous areas higher than 90%,whereas the two other methods identified 60%(maximum)of the anomalous areas.The raw data without any estimation for the concentration was used by the MPD method using aminimum of calculations to determine the threshold values.Therefore,the MPD method is more robust than the other methods.The spatial analysis identified the detail soft hegeological and mineralization events that were affected in the study area.MPD is recommended as the best,and the spatial U-analysis is the next reliable method to be used.The fractal method could show more detail of the events and variations in the area with asymmetrical grid net and a higher density of sampling or at the detailed exploration stage.
文摘Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscillations, caused by weak but long-lasting and frequency-stable influences, create the conditions for ultrasonic wave’s generation in the layers, which are capable of destroying thickened oil membranes in reservoir cracks. For fractured-porous reservoirs in the process of exploitation by the method of water high-pressure oil displacement, the possibility of intensifying ultrasonic vibrations can have an important technological significance. Even a very weak ultrasound can destroy, over a long period of time, the viscous oil membranes formed in the cracks between the blocks, which can be the reason for lowering the permeability of the layers and increasing the oil recovery. To describe these effects, it is necessary to consider the wave process in a hierarchically blocky environment and theoretically simulate the mechanism of the appearance of self-oscillations under the action of relaxation shear stresses. For the analysis of seism acoustic response in time on fixed intervals along the borehole an algorithm of phase diagrams of the state of many-phase medium is suggested.
文摘Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the simplex method. This method is suitable for the calculation of the stable equilibria in complicated systems. For example. calculated results in comparison with experimental results as well as the prediction of new systems were shown in the present work
文摘A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.The solubility of oxygen in Mn and the composition of the interface between MnO and Mn were determined.Partial phase diagram of Mn-MnO system were constructed according to pres- ent experimental results.
基金funded by the National Key R&D Program of China(Nos.2023YFE0101800 and 2023YFC 3007305)National Natural Science Foundation of China(Nos.42004069 and 42204093)Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB24X24).
文摘Since the 1975 M_(S)7.3 Haicheng earthquake,spatio-temporal variations in the gravity field have attracted much attention as potential earthquake precursors.Recent technical advances in terrestrial gravity observation,along with the construction of a high-precision mobile gravity network covering Chinese mainland,have positioned temporal gravity variations(GVs)as an important tool for clarifying the signal characteristics and dynamic mechanisms of crustal sources.Reportedly,crustal mass transfer,which is affected by stress state and structural environment,alters the characteristics of the regional gravity field,thus serving as an indicator for locations of moderate to strong earthquakes and a seismology-independent predictor for regions at risk for strong earthquakes.Therefore,quantitatively tracking time-varying gravity is of paramount importance to enhance the effectiveness of earthquake prediction.In this study,we divided the areas effectively covered by the terrestrial mobile gravity network in the Sichuan-Yunnan region into small grids based on the latest observational data(since 2018)from the network.Next,we calculated the 1-and 3-year GVs and gravity gradient indicators(amplitude of analytic signal,AAS;total horizontal derivative,THD;and amplitude of vertical gradient,AVG)to quantitatively characterize variations in regional time-varying gravity field.Next,we assessed the effectiveness of gravity field variations in predicting earthquakes in the Sichuan-Yunnan region using Molchan diagrams constructed for gravity signals of 13 earthquakes(M≥5.0;occurred between 2021 and 2024)within the terrestrial mobile gravity network.The results reveal a certain correspondence between gravity field variations and the locations of moderate and strong earthquakes in the Sichuan-Yunnan region.Furthermore,the 3-year AAS and AVG outperform the 3-year THD in predicting subsequent seismic events.Notably,the AAS and AVG showed large probability gains prior to the M_(S)6.8 Luding earthquake,indicating their potential for earthquake prediction.
