Based on the data from 4 times of repeated measurements (1996-1999) of GPS monitoring network arranged along Shanxi fault zone, the current horizontal movement of Shanxi fault zone and its relationship with Yangyuan-H...Based on the data from 4 times of repeated measurements (1996-1999) of GPS monitoring network arranged along Shanxi fault zone, the current horizontal movement of Shanxi fault zone and its relationship with Yangyuan-Hunyuan earthquake (M=5.6; 39.8°N, 113.9°E; November 1, 1999) which occurred at the north part of the monitoring network is analyzed. The results from the analysis indicate: (1) The horizontal movement along Shanxi fault zone was not obvious from 1996 to 1997; (2) The intensity of horizontal movement along Shanxi fault zone increased at the period of 1997 to 1998, and there are three areas with relatively higher strain (1×10-6) appeared, i.e., the source region, Xinzhou region and northeastern part of Jiexiu; (3) Although the dominant movement direction of Shanxi fault zone in the period of 1998 to 1999 was consistent with the fault striking direction, but as compared with the movement in the passed year, the direction was almost reversed, while the absolute value of the movement was close each other; (4) The accumulated horizontal movement along Shanxi fault zone from 1996 to 1999 became obvious gradually. It can be divided into three parts by considering its tendency: (a) the dominant direction of movement in north of Xinzhou is NNE (0.8 cm); (b) in south of Quwo it is SSW (1 cm); (c) in the central area it is rather complicated, the deformation in the southern part is little more large, but in the view of whole area there is no dominant movement exist. Generally speaking, Shanxi fault zone is mainly controlled by the NNE-SSW-trending extension stress field, but there is no strike-slip movement. In the period of 1997 to 1998, there might be a clear stress disturb and it was essentially recovered in 1999. Then the Yangyuan-Hunyuan earthquake occurred. Very possible, this disturb is the triggering to the earthquake.展开更多
The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new ...The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage （UPMS） with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.展开更多
Based on the high-accuracy data obtained from the GPS measurements carried out in 1992, 1995 and 1996, the isochronous active units with different kinematic property inside the North China area have been distinguished...Based on the high-accuracy data obtained from the GPS measurements carried out in 1992, 1995 and 1996, the isochronous active units with different kinematic property inside the North China area have been distinguished, 4 active units and 1 transition zone with distinct differential movement have been determined. They are Ordos-Yinshan unit, Yanshan unit, Shanxi-Hebei-Shandong (Jin-Ji-Lu) unit, Jiaodong-Liaoning-Shandong (Jiao-Liao-Lu) unit and Yanshan-Hebei (Yan-Ji) transition zone. The relative movements among the neighboring units in this period have been given. ① The compressive movement between Ordos-Yinshan unit and Yanshan unit is not obvious with an amount of 0.4(1.3 mm/a.②in-Ji-Lu unit moves E40(S off the Ordos-Yinshan unit and the magnitude is 4.4(1.0 mm/a. ③elative to the Yan-Ji transition zone of differential movement, Yanshan unit shifts W38(N with a value of 2.4(1.3 mm/a and Jin-Ji-Lu unit moves eastward 35( by south with an amount of 2.3(0.9 mm/a. ④Jin-Ji-Lu unit has a tensional left-lateral movement of 4.7(1.4 mm/a in the direction of E37(S relative to Yanshan unit. ⑤ Some area near Tanlu belt which is located in the southern part of Jin-Ji-Lu block has a southward movement 14( by west with a magnitude of 1.5(1.1 mm/a off the Jin-Ji-Lu unit. ⑥ Relative to Jin-Ji-Lu unit, Jiao-Liao-Lu unit has a trend of clockwise movement with a tensional right-lateral motion at the north end which neighbors Yanshan unit and a compressive motion at the south end. It should be noted that the errors given in the paper are obtained based on the divergence among the displacements of the sites in the unit, rather than the value calculated from the displacement error of the sites. The analyzed results indicate that: ① Shanxi tectonic zone and Yan-Ji transition zone are the major tectonic active zones to show the frame and magnitude of interior relative movement in North China area, and others are the secondary tectonic active zones; ② The complete horizontal deformation in the North China area is not homogeneous nor successive; ③ The kinetic model of North China area might be (mantle dragging plus boundary coupling(.展开更多
In this paper,a method of multipoint pseudorandom combined excita-tion with the orthogonal reciprocal repeated sequences(ORRS)is presented on thebackground of the on-line identification of multivariate system.The capa...In this paper,a method of multipoint pseudorandom combined excita-tion with the orthogonal reciprocal repeated sequences(ORRS)is presented on thebackground of the on-line identification of multivariate system.The capacity of therestraint to the identification error caused by the non-random D.C.drift of the mul-ti-input excitation with the ORRS in the multivariate system is also discussed.Thevalidity of the method described in this paper is proved by the modelling tests of themulti-plate rotor system.展开更多
All lunar theories within the framework of classical mechanics are based on the assumption of an inertial frame of reference,which is physically non-existent and has scarcely been examined in previous studies.This pap...All lunar theories within the framework of classical mechanics are based on the assumption of an inertial frame of reference,which is physically non-existent and has scarcely been examined in previous studies.This paper aims to examine the consequence of giving up the assumption of the existence of an inertial frame and the relevant influence on the measured moon trajectories.The general formulation of the lunar orbit is built from the perspective of the new general system theory(NGST),where the moon is modelled as a 6-DOF living body and active forces are introduced.This formulation can be retrograded to the framework of classical mechanics.Firstly,we calculate the active forces on the moon when a fixed earth movement and a fixed moon movement are assumed in the god-coordinate system.Then we investigate what will happen to the measured moon trajectory in the human-coordinate system when the earth movement and other parameters are perturbed in several cases.It is found that the results are sometimes inconsistent with the explanations using inertia forces in classical mechanics but can be well explained by NGST.We also discovered that the active forces on the moon should be adjusted constantly to maintain the stable measured moon trajectory.展开更多
The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, t...The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, the velocity field for the Eurasia reference framework was obtained. Based on the velocity field, the present-day velocities of the blocks and boundary faults were estimated. The results reveal that the movement rates of the Chuan-Qing, South China, Chuan-Dian and Indo-China blocks are（17.02±0.60） mm/a,（8.77±1.51） mm/a,（13.85±1.31） mm/a and（6.84 ± 0.74） mm/a, respectively, and their movement directions are 99.5°, 120.3°, 142.9° and 153.3°, respectively. All blocks exhibit clockwise rotation. The displacement rates of the Xianshuihe, Longmenshan, Anninghe, Zemuhe, Xiaojiang and Red River faults are（7.30±1.25–8.30±1.26） mm/a,（10.07±0.97–11.79±0.89） mm/a,（0.96±0.74–2.98±1.73） mm/a,（2.03±0.49–3.20±0.73） mm/a,（3.45±0.40–6.02±0.50） mm/a and（6.23±0.56） mm/a, respectively. The Xianshuihe, Anninghe, Zemuhe and Xiaojiang faults show leftlateral strike-slip movement, while the Longmenshan and Red River faults show right-lateral strikeslip. These characteristics of the blocks and faults are related to the particular tectonic location and dynamic mechanism.展开更多
AIM: To construct a new visual acuity measuring function for congenital nystagmus(CN) patients by studying the relationships between acuity,velocities and positions of the eye. ·METHODS: After assessing the relat...AIM: To construct a new visual acuity measuring function for congenital nystagmus(CN) patients by studying the relationships between acuity,velocities and positions of the eye. ·METHODS: After assessing the relationship between acuity,movement velocities and positions of the eye separately,a new function,which we call the automated nystagmus acuity function(ANAF),was constructed to measure the visual acuity of CN patients. Using a high-speed digital video system working at 500 frames per second,each eye was calibrated during monocular fixation. Twenty-six recorded nystagmus data were selected randomly. Using nystagmus waveforms,the best vision position(foveation period) and visual acuity were analyzed in three groups of subjects,and then all outputs were compared with the well-known expanded nystagmus acuity function(NAFX) and ANAF. Standard descriptive statistics were used to summarize the outputs of the two programs. ·RESULTS: Foveation periods were brief intervals in the CN waveform when the image was on or near the fovea and eye velocity was relatively slow. Results showed good visual acuity happened during the period when velocity was low and the eye position was near the zero position,which fitted the foveation periods. The data analyzed with NAFX and ANAF had a correlation coefficient of 0.934276,with an average error of-0.00973. · CONCLUSION: The results from ANAF and NAFX analyses showed no significant difference. The NAFX manually identifies foveation eye positions and produces accurate measurements. The ANAF,however,can be calculated simply using the factors eye position andvelocity,and it automatically calculates the ANAF without the need to manually identify foveation eye positions.展开更多
ms paper proposes a set of objective and quantitative human motion evaluation indices, among Which the index of difficulty and index of performance are introduced as the general indices for the quality measure of 2-D ...ms paper proposes a set of objective and quantitative human motion evaluation indices, among Which the index of difficulty and index of performance are introduced as the general indices for the quality measure of 2-D target-to-talget movement. As an example, the target-reaching movement of index finger, which is a basic functional action of index finger in the daily life of hUman beings, were experimentally investigated. In the experiment five healthy male subjects were asked to perform three target-reaching movement tasks Which have different indices of difficulty. All movements were recorded by a 3-D motion analysis system. Later, their motion qualities were measured with these evaluation metrics. The results showed that these indices are reasonable and have potential applications to biomedical engineering.展开更多
Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequen...Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequent climatic changes increase the potential landslides.The possible deformation and failure process of potential landslides and their impacts on the surrounding environment are important research topics.Field investigation and monitoring indicate that the Qingliu landslide in Xiameng town,Li County,Sichuan Province,China has been continuously deforming since August 2020.The deformation zone has a maximum deformation depth of approximately 18.9m,a total area of 54,628 m2,and a volume of 34.0×104 m3,which seriously threatens infrastructure projects and dwellings.As a result,understanding the Qingliu landslide evolution process,assessing the hazard risk,and planning disaster prevention measures are of great significance for reducing disaster loss.In this study,the mass movement process and hazard risk of the Qingliu landslide are evaluated,and the effects of different prevention measures are compared and discussed.By using the depth-integrated method,the mass movement of the Qingliu landslide is analyzed.The numerical simulation results indicate that the maximum velocity of the Qingliu landslide is approximately 37.5 m/s,and the duration of the landslide is approximately 90s.The simulated landslide can eventually form a deposited mass with a maximum deposit thickness of 19.4 m and an area of approximately 60,168.3 m2,thereby blocking the river and burying dwellings.Furthermore,a risk assessment of the Qingliu landslide under different forms of protection measures is also produced and discussed by considering the hazard level and economic vulnerability level of the affected area.Setting three layers of anti-slide piles on the deformation zone to reduce the hazard risk of the Qingliu landslide is a better choice.Our results may be useful for planning prevention measures and improving disaster emergency response systems.展开更多
基金The Project (Continental Geodynamics and Continental Earthquakes! (95-13-03-06).
文摘Based on the data from 4 times of repeated measurements (1996-1999) of GPS monitoring network arranged along Shanxi fault zone, the current horizontal movement of Shanxi fault zone and its relationship with Yangyuan-Hunyuan earthquake (M=5.6; 39.8°N, 113.9°E; November 1, 1999) which occurred at the north part of the monitoring network is analyzed. The results from the analysis indicate: (1) The horizontal movement along Shanxi fault zone was not obvious from 1996 to 1997; (2) The intensity of horizontal movement along Shanxi fault zone increased at the period of 1997 to 1998, and there are three areas with relatively higher strain (1×10-6) appeared, i.e., the source region, Xinzhou region and northeastern part of Jiexiu; (3) Although the dominant movement direction of Shanxi fault zone in the period of 1998 to 1999 was consistent with the fault striking direction, but as compared with the movement in the passed year, the direction was almost reversed, while the absolute value of the movement was close each other; (4) The accumulated horizontal movement along Shanxi fault zone from 1996 to 1999 became obvious gradually. It can be divided into three parts by considering its tendency: (a) the dominant direction of movement in north of Xinzhou is NNE (0.8 cm); (b) in south of Quwo it is SSW (1 cm); (c) in the central area it is rather complicated, the deformation in the southern part is little more large, but in the view of whole area there is no dominant movement exist. Generally speaking, Shanxi fault zone is mainly controlled by the NNE-SSW-trending extension stress field, but there is no strike-slip movement. In the period of 1997 to 1998, there might be a clear stress disturb and it was essentially recovered in 1999. Then the Yangyuan-Hunyuan earthquake occurred. Very possible, this disturb is the triggering to the earthquake.
文摘The accuracy and repeatability of the laser interferometer measurement system （LIMS） are often limited by the mirror surface error that comes from the mirror surface shape and distortion. This paper describes a new method to calibrate mirror map on ultraprecise movement stage （UPMS） with nanopositioning and to make a real-time compensation for the mirror surface error by using mirror map data tables with the software algorithm. Based on the mirror map test model, the factors affecting mirror map are analyzed through geometric method on the UPMS with six digrees of freedom. Dam processing methods including spline interpolation and spline offsets are used to process the raw sampling data to build mirror map tables. The linear interpolation as compensation method to make a real-time correction on the stage mirror unflatness is adopted and the correction formulas are illuminated. In this way, the measurement accuracy of the system is obviously improved from 40 nm to 5 nm.
基金The National Key Basic Research Project Mechanism and Prediction of Continental Earthquakes (G1998040700).
文摘Based on the high-accuracy data obtained from the GPS measurements carried out in 1992, 1995 and 1996, the isochronous active units with different kinematic property inside the North China area have been distinguished, 4 active units and 1 transition zone with distinct differential movement have been determined. They are Ordos-Yinshan unit, Yanshan unit, Shanxi-Hebei-Shandong (Jin-Ji-Lu) unit, Jiaodong-Liaoning-Shandong (Jiao-Liao-Lu) unit and Yanshan-Hebei (Yan-Ji) transition zone. The relative movements among the neighboring units in this period have been given. ① The compressive movement between Ordos-Yinshan unit and Yanshan unit is not obvious with an amount of 0.4(1.3 mm/a.②in-Ji-Lu unit moves E40(S off the Ordos-Yinshan unit and the magnitude is 4.4(1.0 mm/a. ③elative to the Yan-Ji transition zone of differential movement, Yanshan unit shifts W38(N with a value of 2.4(1.3 mm/a and Jin-Ji-Lu unit moves eastward 35( by south with an amount of 2.3(0.9 mm/a. ④Jin-Ji-Lu unit has a tensional left-lateral movement of 4.7(1.4 mm/a in the direction of E37(S relative to Yanshan unit. ⑤ Some area near Tanlu belt which is located in the southern part of Jin-Ji-Lu block has a southward movement 14( by west with a magnitude of 1.5(1.1 mm/a off the Jin-Ji-Lu unit. ⑥ Relative to Jin-Ji-Lu unit, Jiao-Liao-Lu unit has a trend of clockwise movement with a tensional right-lateral motion at the north end which neighbors Yanshan unit and a compressive motion at the south end. It should be noted that the errors given in the paper are obtained based on the divergence among the displacements of the sites in the unit, rather than the value calculated from the displacement error of the sites. The analyzed results indicate that: ① Shanxi tectonic zone and Yan-Ji transition zone are the major tectonic active zones to show the frame and magnitude of interior relative movement in North China area, and others are the secondary tectonic active zones; ② The complete horizontal deformation in the North China area is not homogeneous nor successive; ③ The kinetic model of North China area might be (mantle dragging plus boundary coupling(.
文摘In this paper,a method of multipoint pseudorandom combined excita-tion with the orthogonal reciprocal repeated sequences(ORRS)is presented on thebackground of the on-line identification of multivariate system.The capacity of therestraint to the identification error caused by the non-random D.C.drift of the mul-ti-input excitation with the ORRS in the multivariate system is also discussed.Thevalidity of the method described in this paper is proved by the modelling tests of themulti-plate rotor system.
基金This work was supported by the Startup Funding of New-Joined PI of Westlake University with Grant No.041030150118 and Scientific Research Funding Project of Westlake University under Grant No.2021WUFP017.
文摘All lunar theories within the framework of classical mechanics are based on the assumption of an inertial frame of reference,which is physically non-existent and has scarcely been examined in previous studies.This paper aims to examine the consequence of giving up the assumption of the existence of an inertial frame and the relevant influence on the measured moon trajectories.The general formulation of the lunar orbit is built from the perspective of the new general system theory(NGST),where the moon is modelled as a 6-DOF living body and active forces are introduced.This formulation can be retrograded to the framework of classical mechanics.Firstly,we calculate the active forces on the moon when a fixed earth movement and a fixed moon movement are assumed in the god-coordinate system.Then we investigate what will happen to the measured moon trajectory in the human-coordinate system when the earth movement and other parameters are perturbed in several cases.It is found that the results are sometimes inconsistent with the explanations using inertia forces in classical mechanics but can be well explained by NGST.We also discovered that the active forces on the moon should be adjusted constantly to maintain the stable measured moon trajectory.
基金supported by a geological survey project of the China Geological Survey(No.1212011140013,No.12120113009800,No.121201010000150001)
文摘The geology and tectonics in the eastern margin of Tibetan Plateau are complex. The main tectonic framework is composed of blocks and faults. Using discontinuous global positioning system survey data for 2008–2014, the velocity field for the Eurasia reference framework was obtained. Based on the velocity field, the present-day velocities of the blocks and boundary faults were estimated. The results reveal that the movement rates of the Chuan-Qing, South China, Chuan-Dian and Indo-China blocks are（17.02±0.60） mm/a,（8.77±1.51） mm/a,（13.85±1.31） mm/a and（6.84 ± 0.74） mm/a, respectively, and their movement directions are 99.5°, 120.3°, 142.9° and 153.3°, respectively. All blocks exhibit clockwise rotation. The displacement rates of the Xianshuihe, Longmenshan, Anninghe, Zemuhe, Xiaojiang and Red River faults are（7.30±1.25–8.30±1.26） mm/a,（10.07±0.97–11.79±0.89） mm/a,（0.96±0.74–2.98±1.73） mm/a,（2.03±0.49–3.20±0.73） mm/a,（3.45±0.40–6.02±0.50） mm/a and（6.23±0.56） mm/a, respectively. The Xianshuihe, Anninghe, Zemuhe and Xiaojiang faults show leftlateral strike-slip movement, while the Longmenshan and Red River faults show right-lateral strikeslip. These characteristics of the blocks and faults are related to the particular tectonic location and dynamic mechanism.
基金Supported by National Natural Sciences Foundation of China(No.81070749)
文摘AIM: To construct a new visual acuity measuring function for congenital nystagmus(CN) patients by studying the relationships between acuity,velocities and positions of the eye. ·METHODS: After assessing the relationship between acuity,movement velocities and positions of the eye separately,a new function,which we call the automated nystagmus acuity function(ANAF),was constructed to measure the visual acuity of CN patients. Using a high-speed digital video system working at 500 frames per second,each eye was calibrated during monocular fixation. Twenty-six recorded nystagmus data were selected randomly. Using nystagmus waveforms,the best vision position(foveation period) and visual acuity were analyzed in three groups of subjects,and then all outputs were compared with the well-known expanded nystagmus acuity function(NAFX) and ANAF. Standard descriptive statistics were used to summarize the outputs of the two programs. ·RESULTS: Foveation periods were brief intervals in the CN waveform when the image was on or near the fovea and eye velocity was relatively slow. Results showed good visual acuity happened during the period when velocity was low and the eye position was near the zero position,which fitted the foveation periods. The data analyzed with NAFX and ANAF had a correlation coefficient of 0.934276,with an average error of-0.00973. · CONCLUSION: The results from ANAF and NAFX analyses showed no significant difference. The NAFX manually identifies foveation eye positions and produces accurate measurements. The ANAF,however,can be calculated simply using the factors eye position andvelocity,and it automatically calculates the ANAF without the need to manually identify foveation eye positions.
文摘ms paper proposes a set of objective and quantitative human motion evaluation indices, among Which the index of difficulty and index of performance are introduced as the general indices for the quality measure of 2-D target-to-talget movement. As an example, the target-reaching movement of index finger, which is a basic functional action of index finger in the daily life of hUman beings, were experimentally investigated. In the experiment five healthy male subjects were asked to perform three target-reaching movement tasks Which have different indices of difficulty. All movements were recorded by a 3-D motion analysis system. Later, their motion qualities were measured with these evaluation metrics. The results showed that these indices are reasonable and have potential applications to biomedical engineering.
基金the support of the National Natural Science Foundation of China(U2240221,41977229)the Sichuan Youth Science and Technology Innovation Research Team Project(2020JDTD0006)the Sichuan Provincial International Science and Technology Collaboration&Innovation Project(2020YFH0092)。
文摘Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequent climatic changes increase the potential landslides.The possible deformation and failure process of potential landslides and their impacts on the surrounding environment are important research topics.Field investigation and monitoring indicate that the Qingliu landslide in Xiameng town,Li County,Sichuan Province,China has been continuously deforming since August 2020.The deformation zone has a maximum deformation depth of approximately 18.9m,a total area of 54,628 m2,and a volume of 34.0×104 m3,which seriously threatens infrastructure projects and dwellings.As a result,understanding the Qingliu landslide evolution process,assessing the hazard risk,and planning disaster prevention measures are of great significance for reducing disaster loss.In this study,the mass movement process and hazard risk of the Qingliu landslide are evaluated,and the effects of different prevention measures are compared and discussed.By using the depth-integrated method,the mass movement of the Qingliu landslide is analyzed.The numerical simulation results indicate that the maximum velocity of the Qingliu landslide is approximately 37.5 m/s,and the duration of the landslide is approximately 90s.The simulated landslide can eventually form a deposited mass with a maximum deposit thickness of 19.4 m and an area of approximately 60,168.3 m2,thereby blocking the river and burying dwellings.Furthermore,a risk assessment of the Qingliu landslide under different forms of protection measures is also produced and discussed by considering the hazard level and economic vulnerability level of the affected area.Setting three layers of anti-slide piles on the deformation zone to reduce the hazard risk of the Qingliu landslide is a better choice.Our results may be useful for planning prevention measures and improving disaster emergency response systems.
