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Quantifying of spatio-temporal variations in the regional gravity field and the effectiveness of earthquake prediction:A case study of M_(S)≥5.0 earthquakes in the Sichuan-Yunnan region during 2021-2024
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作者 Weimin Xu Shi Chen +9 位作者 Yongbo Li Jiangpei Huang Bing Zheng Yufei Han Zhaohui Chen Qiuyue Zheng Hongyan Lu Linhai Wang Honglei Li Dong Liu 《Earthquake Science》 2025年第4期375-390,共16页
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
关键词 gravity variation sichuan-yunnan region molchan diagram method earthquake precursor prediction efficacy
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The efficiency and accuracy of probability diagram, spatial statistic and fractal methods in the identification of shear zone gold mineralization: a case study of the Saqqez gold ore district,NW Iran 被引量:1
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作者 Mirmahdi Seyedrahimi-Niaraq Amin Hekmatnejad 《Acta Geochimica》 EI CAS CSCD 2021年第1期78-88,共11页
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
关键词 Shear zone gold deposit Modeling of probability diagram method Concentration-area fractal method U-spatial statistics method Phases of efficiency and accuracy mineralization
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Coefficient Diagram Method Based Load Frequency Control for a Modern Power System
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作者 Princess Garasi Yaser Qudaih +2 位作者 Raheel Ali Masayuki Watanabe Yasunori Mitani 《Journal of Electronic Science and Technology》 CAS 2014年第3期270-276,共7页
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
关键词 BATTERY coefficient diagram method electric vehicles heat pump load frequency control renewable energy sources.
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DETERMINATION OF THE PHASE BOUNDARY OF AI-Mg-Y ALLOY EQUILIBRIUM DIAGRAM IN THE Al-RICH CORNER BY X-RAY METHOD
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作者 龙骧 朱定华 +2 位作者 宋利珠 徐惠平 管清录 《Journal of Rare Earths》 SCIE EI CAS CSCD 1990年第3期228-230,共3页
关键词 AI In DETERMINATION OF THE PHASE BOUNDARY OF AI-Mg-Y ALLOY EQUILIBRIUM DIAGRAM IN THE Al-RICH CORNER BY X-RAY method Al
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Practical Application of Two-Way Multiple Overlapping Relationships in a BDM Network
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作者 Seon-Gyoo Kim 《Journal of Civil Engineering and Architecture》 2016年第12期1318-1328,共11页
Today, most construction projects in urban environments are complex high-rise buildings that present unique challenges, including local building ordinances and restrictions, adjoining public and residential areas, nar... Today, most construction projects in urban environments are complex high-rise buildings that present unique challenges, including local building ordinances and restrictions, adjoining public and residential areas, narrow sidewalks and streets, and underground utilities, all of which require extensive planning and tight schedules. A major problem facing such projects is to formulate realistic schedules that will make it possible to meet contractual completion dates with limited resources and budgets. The scheduling software products currently used in construction projects, which include Primavera P6, Microsoft Project, etc., are not actually applied as a scheduling tool in practical construction projects, which instead generally depend on Microsoft Excel or a bar-chart. This is because the existing scheduling programs cannot provide more user-oriented schedule format such as representing two-way multiple overlapping relationships. To overcome this deficiency, the BDM (beeline diagramming method) is proposed as a new networking technique in 2010. But two-way multiple overlapping relationships generate the loop in a conventional schedule computation process. This paper addresses the loop phenomenon of two-way multiple overlapping relationships in a BDM network as well as proposes the solutions of them, and then presents a practical application of two-way multiple overlapping relationships at a real project. 展开更多
关键词 Critical path method beeline diagramming method schedule computation two-way multiple overlapping relationships consecutive activities.
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Two New Control Signal Approaches for Obtaining the MRAS-CDM and a Real-time Application
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作者 mr cal Atilla Bir Bernd Tibken 《International Journal of Automation and computing》 EI 2011年第2期254-261,共8页
The coefficient diagram method (CDM) is one of the most effective control design methods. It creates control systems that are very stable and robust with responses without the overshoot and small settling time. Furt... The coefficient diagram method (CDM) is one of the most effective control design methods. It creates control systems that are very stable and robust with responses without the overshoot and small settling time. Furthermore, all control parameters of the control systems are changed by varying some adjustment parameters in CDM depending on the demands. The model reference adaptive systems (MRAS) are the systems that follow and change the control parameters according to a given model reference system. There are several methods to combine the CDM with MRAS. One of these is to use the MRAS parameters as a gain of the CDM parameters. Another is to directly use the CDM parameters as the MRAS parameters. In the industrial applications, the system parameters can be changed frequently, but if the controller, by self-tuning, recalculates and develops its own parameters continuously, the system becomes more robust. Also, if the poles of the controlled systems approach the jw axis, the response of the closed-loop MRAS becomes more and more insufficient. In order to obtain better results, CDM is combined with a self-tuning model reference adaptive system. Systems controlled by a model reference adaptive controller give responses with small or without overshoot, have small settling times, and are more robust. Thus, in this paper, a hybrid combination of MRAS and CDM is developed and two different control structures of the control signal are investigated. The two methods are compared with MRAS and applied to real-time process control systems. 展开更多
关键词 Coefficient diagram method (CDM) coefficient diagram method adaptive control process control model reference adaptive systems (MRAS).
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Single-peak distribution model of particulate size for welding aerosols
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作者 施雨湘 李爱农 《China Welding》 EI CAS 2003年第1期45-49,共5页
A large number of particulate size distributions of welding aerosols are measured by means of DMPS method, several distribution types are presented. Among them the single peak distribution is the basic composing unit... A large number of particulate size distributions of welding aerosols are measured by means of DMPS method, several distribution types are presented. Among them the single peak distribution is the basic composing unit of particulate size. The research on the mathematic models and distributions functions shows that the single peak distribution features the log normal distribution. The diagram estimating method (DEM) is a concise approach to dealing with distribution types, obtaining distribution functions for the particulate sizes of welding aerosols. It proves that the distribution function of particulate size possesses the extending property, being from quantity distribution to volume, as well as high order moment distributions, with K S method verifying the application of single peak distribution and of DEM. 展开更多
关键词 welding aerosols distribution function log normal distribution diagram estimating method (DEM) welding fume
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Numerical Fitting of Planar Photographic Images with Spherical Voronoi Diagrams
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作者 CHAIDEE Supanut SUGIHARA Kokichi 《Computer Aided Drafting,Design and Manufacturing》 2015年第4期26-31,共6页
There are many phenomena that generate polygonal tessellations on surfaces of 3D objects. One interesting example is the jackfruit, a multiple fruit found in the tropics. A recent study found the best-fit spherical Vo... There are many phenomena that generate polygonal tessellations on surfaces of 3D objects. One interesting example is the jackfruit, a multiple fruit found in the tropics. A recent study found the best-fit spherical Voronoi diagram from a photo of jackfruit skin, but the optimization was relative to the radius of the sphere and the height of the spikes. In this study, we propose a method for adjusting the position of the center of the sphere in addition to these parameters. Experiments were conducted using both ideal and real data. However, convergence with real data has not been confirmed due to relaxation of the convergence condition. 展开更多
关键词 spherical voronoi diagram jackfruit discrepancy circular search method of steepest descent
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Studies on the Refolding of Egg White Lysozyme Denatured by Urea Using "Phase Diagram" Method of Fluorescence
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作者 边六交 董发昕 +2 位作者 梁长利 杨晓燕 刘莉 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2007年第12期1896-1903,共8页
The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence. The result showed that in the refolding of the reduced egg white lysozyme, an... The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence. The result showed that in the refolding of the reduced egg white lysozyme, an intermediate state of an egg white lysozyme exists at the urea concentrations in a final renaturation solution being about 4.5 mol/L, their refolding follows a three-state model; while in the refolding of the non-reducing egg white lysozyme, two intermediate states exist at the urea concentrations being separately 4.0 and 2.5 mol/L, and their refolding follows a four-state model. Through the comparison between the unfolding and refolding of an egg white lysozyme in the urea solution, it was found that both of the refolding of reduced and non-reducing egg white lysozyme molecules was irreversible to their unfolding in the urea solution. Finally, a suggested refolding was separately presented for the reduced and non-reducing egg white lysozymes in the urea solution. 展开更多
关键词 egg white lysozyme "phase diagram" method of fluorescence REFOLDING UREA
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Cause Analysis of Hanegi
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作者 Zhang Yijie Dai Mingzhu Ma Zhitao 《中国建筑史论汇刊》 2019年第2期303-310,共8页
Hanegi is a structural timber typical for traditional Japanese architecture.This paper analyzes the hanegi installed in the pagoda at Hokiji from a structural perspective.The gentle sloped roof and the deep projecting... Hanegi is a structural timber typical for traditional Japanese architecture.This paper analyzes the hanegi installed in the pagoda at Hokiji from a structural perspective.The gentle sloped roof and the deep projecting eaves are two remarkable features of wooden buildings of the Chinese Tang dynasty.When those features were introduced to Japan,problems arose due to the different environment.To solve those problems,the Japanese builders created a double-layer roof and used hanegi.The main function of hanegi is to bear the weight of the roof and transmit the load downward,preventing the rafters from bearing load.This is an indigenous Japanese modification of technology from China's Mainland:Japanese were inspired by technology from China but not dependent on it. 展开更多
关键词 hanegi rough or hidden roof(caojia wumian in Chinese noyane in Japanese) lever diagram multiplication method
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