Company is a kind of effective organizational form of modern enterprise system. In connection with China’s real situation, change from the old factory system of part of the large and medium-sized state enterprises to...Company is a kind of effective organizational form of modern enterprise system. In connection with China’s real situation, change from the old factory system of part of the large and medium-sized state enterprises to company system is an important reform. The company system will play a significant role in shifting enterprises’ operational mechanism and sharpening their competitive edge.展开更多
The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of h...The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of high-precision observations,and low efficiency in real-time data processing.These issues inevitably affect the quality of seismic exploration outcomes.To address these challenges and enhance the accuracy of geophone positioning,this paper proposes a rigorous real-time acoustic positioning method for geophones based on sequential adjustment and Baarda's outlier detection approach.The proposed method comprises three key steps:grouping the original acoustic observations,constructing the intra-group acoustic positioning model,and synthesizing the positioning results across the different groups.The validity and practicality of this approach are confirmed through a simulation experiment as well as the field experiment conducted in the Bohai Sea,China.The results demonstrate that the proposed method effectively eliminates outliers in the original observations and maximizes the utilization of high-quality observations.Compared to traditional acoustic positioning methods,it significantly reduces positioning errors from meters to decimeters,and in some cases can achieve centimeter-level precision.When the sound velocity profile in the operating sea area is measured,the method can attain the posterior standard deviation at the millimeter level and positioning errors within 10 cm.When the sound velocity profile is unknown,the method can achieve the posterior standard deviation at centimeter-level and positioning errors of approximately 20 cm.展开更多
Polymetallic sulphides have been consistent source of metals like iron, copper, zinc and lead. Apart from these they are also seen as economically viable resources of silver and gold. As the demand of these metals is ...Polymetallic sulphides have been consistent source of metals like iron, copper, zinc and lead. Apart from these they are also seen as economically viable resources of silver and gold. As the demand of these metals is showing an astoundingly increasing trend, the search for their resources has also increased in similar folds. This has resulted in many nations' focus on deep seabed resources of the polymetallic sulphides. Consequently, International Seabed Authority (ISBA) has provided 'Regulations' to obtain plan of work for exploration of polymetallic sulphide deposits in deep seabed 'Area'. Following the release of these Regulations, several countries are in the process of obtaining the licence for exploration of these metals from the deep seabed regions. Detailed information about the science and ISBA Regulations for exploration of polymetallic sulphide deposits is prerequisite to submit an application to ISBA for their exploration. The current contribution provides a comprehensive review of the science behind locating polymetallic sulphide deposits in geological setting of deep seabed as well as about the ISBA Regulations for their exploration.展开更多
Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid heigh...Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.展开更多
The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7....The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7.8 earthquake happened. This earthquake occurred at a margin characterized by moderately big to giant earthquakes such as the 1906 （Mw 8.8）. A heavily sedimented trench explains the abnormal lengths of the rupture zones in this system as inhibits the role of natural barriers on the propagation of rupture zones. High amount of sediment thickness is associated with tropical climates, high erosion rates and eastward Pacific dominant winds that provoke orographic rainfalls over the Pacific slope of the Ecuatorian Andes. Offshore sediment dispersion off the oceanic trench is controlled by a close arrangement of two aseismic ridges that hit the Costa Rico and South Ecuador margin respectively and a mid ocean ridge that separates the Cocos and Nazca plate trapping sediments. Gravity field and Ocean Circulation Explorer （GOCE） satellite data are used in this work to test the possible relationship between gravity signal and earthquake rupture structure as well as registered aftershock seismic activity. Reduced vertical gravity gradient shows a good correlation with rupture structure for certain degrees of the harmonic expansion and related depth of the causative mass; indicating, such as in other analyzed cases along the subduction margin, that fore-arc structure derived from density heterogeneities explains at a certain extent propagation of the rupture zones. In this analysis the rupture zone of the April 2016 Ecuador earthquake developed through a relatively low density zone of the fore-arc sliver. Finally, aftershock sequence nucleated around the area of maximum slips in the rupture zone, suggesting that heterogeneous density structure of the fore-arc determined from gravity data could be used in forecasting potential damaged zones associated with big ruptures along the subduction border.展开更多
How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the...How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optima] degrees 90-240 is given, which is recovered by COCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG （Satellite Gravity Gradient） data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbit data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model＇s accuracy matched well with the ESA＇s （European Space Agency） results by using the same data,展开更多
Water is an essential component of the Earth’s climate,but monitoring its properties using autonomous underwater sampling robots remains a significant challenge due to lack of underwater geolocalization capabilities....Water is an essential component of the Earth’s climate,but monitoring its properties using autonomous underwater sampling robots remains a significant challenge due to lack of underwater geolocalization capabilities.Current methods for underwater geolocalization rely on tethered systems with limited coverage or daytime imagery data in clear waters,leaving much of the underwater environment unexplored.Geolocalization in turbid waters or at night has been considered unfeasible due to absence of identifiable landmarks.In this paper,we present a novel method for underwater geolocalization using deep neural networks trained on-10 million polarization-sensitive images acquired globally,along with camera position sensor data.Our approach achieves longitudinal accuracy of-55 km(-1000 km)during daytime(nighttime)at depths up to-8 m,regardless of water turbidity.In clear waters,the transfer learning longitudinal accuracy is-255 km at 50 m depth.By leveraging optical data in conjunction with camera position information,our novel method facilitates underwater geolocalization and offers a valuable tool for untethered underwater navigation.展开更多
文摘Company is a kind of effective organizational form of modern enterprise system. In connection with China’s real situation, change from the old factory system of part of the large and medium-sized state enterprises to company system is an important reform. The company system will play a significant role in shifting enterprises’ operational mechanism and sharpening their competitive edge.
基金supported by the National Key R&D Program of China(Grant No.:2016YFB0501703)Science and Technology Innovation Project(Grant No.:LSKJ202205102)Funded by Laoshan Laboratory.
文摘The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of high-precision observations,and low efficiency in real-time data processing.These issues inevitably affect the quality of seismic exploration outcomes.To address these challenges and enhance the accuracy of geophone positioning,this paper proposes a rigorous real-time acoustic positioning method for geophones based on sequential adjustment and Baarda's outlier detection approach.The proposed method comprises three key steps:grouping the original acoustic observations,constructing the intra-group acoustic positioning model,and synthesizing the positioning results across the different groups.The validity and practicality of this approach are confirmed through a simulation experiment as well as the field experiment conducted in the Bohai Sea,China.The results demonstrate that the proposed method effectively eliminates outliers in the original observations and maximizes the utilization of high-quality observations.Compared to traditional acoustic positioning methods,it significantly reduces positioning errors from meters to decimeters,and in some cases can achieve centimeter-level precision.When the sound velocity profile in the operating sea area is measured,the method can attain the posterior standard deviation at the millimeter level and positioning errors within 10 cm.When the sound velocity profile is unknown,the method can achieve the posterior standard deviation at centimeter-level and positioning errors of approximately 20 cm.
文摘Polymetallic sulphides have been consistent source of metals like iron, copper, zinc and lead. Apart from these they are also seen as economically viable resources of silver and gold. As the demand of these metals is showing an astoundingly increasing trend, the search for their resources has also increased in similar folds. This has resulted in many nations' focus on deep seabed resources of the polymetallic sulphides. Consequently, International Seabed Authority (ISBA) has provided 'Regulations' to obtain plan of work for exploration of polymetallic sulphide deposits in deep seabed 'Area'. Following the release of these Regulations, several countries are in the process of obtaining the licence for exploration of these metals from the deep seabed regions. Detailed information about the science and ISBA Regulations for exploration of polymetallic sulphide deposits is prerequisite to submit an application to ISBA for their exploration. The current contribution provides a comprehensive review of the science behind locating polymetallic sulphide deposits in geological setting of deep seabed as well as about the ISBA Regulations for their exploration.
基金supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar(KZCX2-EW-QN114)the National Natural Science Foundation of China(41004006,41131067,11173049 and 41274041)+7 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(Z01101)the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(11-01-02)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of National Administration of Surveying,Mapping and Geoinformation of China(201322)the Open Research Fund Program of the State Key Laboratory of Geoinformation Engineering,China(SKLGIE2013-M-1-5)the Main Direction Program of Institute of Geodesy and Geophysics,Chinese Academy of Sciences(Y309451045)the Research Fund Program of State Key Laboratory of Geodesy and Earth's Dynamics,China(Y309491050)the Research Fund of the National Civilian Space Infrastructure Project(Y419341034)the Research Fund of the Lu Jiaxi Young Talent and the Youth Innovation Promotion Association of Chinese Academy of Science(Y305171017)
文摘Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.
文摘The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7.8 earthquake happened. This earthquake occurred at a margin characterized by moderately big to giant earthquakes such as the 1906 （Mw 8.8）. A heavily sedimented trench explains the abnormal lengths of the rupture zones in this system as inhibits the role of natural barriers on the propagation of rupture zones. High amount of sediment thickness is associated with tropical climates, high erosion rates and eastward Pacific dominant winds that provoke orographic rainfalls over the Pacific slope of the Ecuatorian Andes. Offshore sediment dispersion off the oceanic trench is controlled by a close arrangement of two aseismic ridges that hit the Costa Rico and South Ecuador margin respectively and a mid ocean ridge that separates the Cocos and Nazca plate trapping sediments. Gravity field and Ocean Circulation Explorer （GOCE） satellite data are used in this work to test the possible relationship between gravity signal and earthquake rupture structure as well as registered aftershock seismic activity. Reduced vertical gravity gradient shows a good correlation with rupture structure for certain degrees of the harmonic expansion and related depth of the causative mass; indicating, such as in other analyzed cases along the subduction margin, that fore-arc structure derived from density heterogeneities explains at a certain extent propagation of the rupture zones. In this analysis the rupture zone of the April 2016 Ecuador earthquake developed through a relatively low density zone of the fore-arc sliver. Finally, aftershock sequence nucleated around the area of maximum slips in the rupture zone, suggesting that heterogeneous density structure of the fore-arc determined from gravity data could be used in forecasting potential damaged zones associated with big ruptures along the subduction border.
基金supported by the National Natural Science Foundation of China(41404020)
文摘How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optima] degrees 90-240 is given, which is recovered by COCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG （Satellite Gravity Gradient） data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbit data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model＇s accuracy matched well with the ESA＇s （European Space Agency） results by using the same data,
基金funded by grants from the Office of Naval Research(N00014-19-1-2400 and N00014-21-1-2177)U.S.Air Force Office of Scientific Research(FA9550-18-1-0278).
文摘Water is an essential component of the Earth’s climate,but monitoring its properties using autonomous underwater sampling robots remains a significant challenge due to lack of underwater geolocalization capabilities.Current methods for underwater geolocalization rely on tethered systems with limited coverage or daytime imagery data in clear waters,leaving much of the underwater environment unexplored.Geolocalization in turbid waters or at night has been considered unfeasible due to absence of identifiable landmarks.In this paper,we present a novel method for underwater geolocalization using deep neural networks trained on-10 million polarization-sensitive images acquired globally,along with camera position sensor data.Our approach achieves longitudinal accuracy of-55 km(-1000 km)during daytime(nighttime)at depths up to-8 m,regardless of water turbidity.In clear waters,the transfer learning longitudinal accuracy is-255 km at 50 m depth.By leveraging optical data in conjunction with camera position information,our novel method facilitates underwater geolocalization and offers a valuable tool for untethered underwater navigation.
