The Sichuan-Yunnan Block(SYB)is located at the SE margin of the Qinghai-Tibetan Plateau(TP).Under the influence of the southeastward movement of material originated from the TP,intense crustal deformation,frequent sei...The Sichuan-Yunnan Block(SYB)is located at the SE margin of the Qinghai-Tibetan Plateau(TP).Under the influence of the southeastward movement of material originated from the TP,intense crustal deformation,frequent seismic activity,and complex geological structures are observed in the SYB.The Lijiang-Xiaojinhe fault(LXF)goes through the central part of the SYB,dividing it into two blocks from north to south,and forming an intersecting fault system with the surrounding faults.This paper firstly introduces the morphology and the nature of the LXF,the distribution of the regional surface displacements and the focal mechanisms,and then analyzes the medium deformation and the effects of faults.Moreover,according to the regional tectonics and geophysical patterns,the paper discusses the characteristics of the north-south blocks of the SYB and the abrupt change of deep structure along the LXF zone.Since seismic anisotropy is an essential property for detecting crustal stress,deep structures and dynamical mechanisms,this paper is dedicated to the advances in seismic anisotropy at different depths and different scales in the study area.There are noteworthy differences in the anisotropic features between the north part and the south part of the SYB,possibly associated with a clear boundary adjacent to the LXF.Such phenomenon suggests some close correlation between anisotropic zoning boundary and the LXF,although this boundary is not consistent with the LXF in strike.The results from the deformation of the crust and the upper mantle elucidate the distribution patterns of the crust-mantle coupling in the north part and the crustmantle decoupling in the south part,even though this conclusion needs to be further verified by more studies.Presently,the scientific understanding of the deep tectonics and the media deformation around the“generalized”LXF i.e.the LXF with the Jinpingshan fault on its eastern side,is still insufficient,and related equivocal topics deserve more in-depth studies.展开更多
The central-southern part of the eastern border of the Sichuan-Yunnan rhombic block provides the research strategy of ‘trade space for time' with an interesting fault system, where the segments have similar focal...The central-southern part of the eastern border of the Sichuan-Yunnan rhombic block provides the research strategy of ‘trade space for time' with an interesting fault system, where the segments have similar focal mechanisms and cover almost continuous spectra of elapse rates. We experiment to study the seismological characteristics of different segments with different elapse rates. We employed the de-clustered earthquake catalog for the calculation of b values for each segment. The analysis revealed that different segments have similar b values,which implies that, although different segments have different periods of earthquake recurrence, the 'natural time' for the whole fault system elapses with a homogeneous pace. We extended the earthquake potential score(EPS)for nowcasting earthquakes to a quasi-EPS(q EPS). It is found that q EPS increases with the increase of elapse rates,albeit for those fault segments whose elapse rates have exceeded 1, q EPS may better reflect the seismic hazard.展开更多
Harvard Centroid Moment Tensor （CMT） solutions for earthquakes from 1977 to 2004 showed that the stress fields are obviously different in northwestern Sichuan sub-block （NWSSB）, western parts of Central Yunnan sub...Harvard Centroid Moment Tensor （CMT） solutions for earthquakes from 1977 to 2004 showed that the stress fields are obviously different in northwestern Sichuan sub-block （NWSSB）, western parts of Central Yunnan sub-block （CYSB） and eastern part of CYSB. The characteristics of the mean stress fields in these three regions are obtained by fitting to CMT solutions. The stress state in NWSSB is characterized by its sub-horizontal tensile principal axis of stress （T axis） in roughly N-S direction and west dipping compressive principal axis of stress （P axis）; the one in western part of CYSB is characterized by its ENE dipping T axis and sub-horizontal medium principal axis of stress （B axis） in roughly N-S direction; the one in eastern part of CYSB is characterized by its sub-horizontal P axis in roughly NNW-SSE direction and sub-horizontal T axis in roughly WSW-ENE direction. Finite element method simulation clearly shows that the Indian Plate imposes great extrusion on Sichuan-Yunnan rhombic block （SYRB） near Assam massif. The value of the simulated compressive principal stress decreases with the distance from Assam massif. The simulated directions of the T axes in SYRB form annular distribution encir cling Assam. For a homogeneous elastic medium with free boundary conditions on the top and bottom surfaces as well as the displacement boundary conditions derived from the GPS observations on the lateral boundaries, the computation results are consistent with the Harvard CMT solutions in NWSSB and western part of CYSB, while inconsistent with the Harvard CMT solutions in eastern part of CYSB. The inconsistency in eastern part of CYSB can be reduced when it includes inhomogeneous elastic media. The stress states in NWSSB and western part of CYSB revealed by the Harvard CMT solutions are not local, which are mainly controlled by the boundary force on the whole region. On the other hand, the stress state in eastern part of CYSB given by the Harvard CMT solutions is local, which may be affected by local topography, material inhomogeneity, and the drag force underneath.展开更多
Based on the seismic station data sets from Sichuan and Yunnan provinces,we employed a multi-step seismic location method( Hypo2000 + Velest + HypoDD) to precisely locate the 7,787 earthquakes that occurred during 201...Based on the seismic station data sets from Sichuan and Yunnan provinces,we employed a multi-step seismic location method( Hypo2000 + Velest + HypoDD) to precisely locate the 7,787 earthquakes that occurred during 2010-2015 along the eastern boundaries of the Sichuan-Yunnan rhombic block,namely from southern Dawu to the Qiaojia segment.The final results show that location precision is greatly advanced and epicenter distribution exhibits good consistency with the linear distribution of the seismic faults. Earthquake distribution is quite intensive at the intersection region in the southern segment of the Xianshuihe fault,the Anninghe fault zone,the Xiaojinhe fault zone and the Daliangshan fault zone to the east. The depth profile of seismicity shows a clear stepwise activity along the active seismic fault zones. The profile crossing the faults of the Xianshuihe,Anninghe,and Daliangshan presents a complex interaction among faults near the multiple faults intersection region,Shimian,where the earthquakes are obviously divided into two groups in depth. Earthquakes are very rare at the depth of 15km-20 km,which is consistent with the region of the plastic rheology between 14km-19 km calculated by Zhu Ailan et al.,( 2005).展开更多
Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation i...Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation is slowing down along the northern segment and increasing along the southern segment. Each fault has different features of deformation. The horizontal deformation is mainly characterized by left-lateral strike-slip. The rate of vertical deformation is less than that of the horizontal deformation. The faults have the feature of upper wall uplifting alternated with descending. The anomaly changes of crustal deformation at some sites are closely related to the seismicities near the sites.展开更多
Deformation characteristics of the Sichuan-Yunnan region during the two periods 1999--2007 and 2007--2009 are analyzed with a block deformation model and GPS velocity profiles. The results show that the direction of t...Deformation characteristics of the Sichuan-Yunnan region during the two periods 1999--2007 and 2007--2009 are analyzed with a block deformation model and GPS velocity profiles. The results show that the direction of the principal compressive strain rate of the Northwest-Sichuan block - the Mid-Yunnan block - the Southwest-Yunnan block was characterized by a clockwise rotation from north to south. The Anninghe and the Zemuhe faults had some shear-strain accumulation. The southern segment of the Xiaojiang fault had mainly strike-slip movement, while the northern segment was mainly accumulating strain. The 2008 Ms8.0 Wenchuan earthquake had some influence on the mid-southern segment of the Lijiang-Xiaojinhe fault, the Anninghe fault and the Jinshajiang fault, but not the Zemuhe fault, the Xiaojiang fault and the Red River fault as much.展开更多
Primary toppling usually occurs in layered rock slopes with large anti-dip angles.In this paper,the block toppling evolution was explored using a large-scale centrifuge system.Each block column in the layered model sl...Primary toppling usually occurs in layered rock slopes with large anti-dip angles.In this paper,the block toppling evolution was explored using a large-scale centrifuge system.Each block column in the layered model slope was made of cement mortar.Some artificial cracks perpendicular to the block column were prefabricated.Strain gages,displacement gages,and high-speed camera measurements were employed to monitor the deformation and failure processes of the model slope.The centrifuge test results show that the block toppling evolution can be divided into seven stages,i.e.layer compression,formation of major tensile crack,reverse bending of the block column,closure of major tensile crack,strong bending of the block column,formation of failure zone,and complete failure.Block toppling is characterized by sudden large deformation and occurs in stages.The wedge-shaped cracks in the model incline towards the slope.Experimental observations show that block toppling is mainly caused by bending failure rather than by shear failure.The tensile strength also plays a key factor in the evolution of block toppling.The simulation results from discrete element method(DEM)is in line with the testing results.Tensile stress exists at the backside of rock column during toppling deformation.Stress concentration results in the fragmented rock column and its degree is the most significant at the slope toe.展开更多
The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification proc...The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient protection.In the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly technique.The outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)film.The FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier capability.The Ce film connects the outer layer with the substrate,showing the transition effect.The corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling behavior.The synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.展开更多
BACKGROUND Ultrasound guide technology,which can provide real-time visualization of the needle tip and tissues and avoid many adverse events,is widely used in mini-mally invasive therapy.However,the studies on ultraso...BACKGROUND Ultrasound guide technology,which can provide real-time visualization of the needle tip and tissues and avoid many adverse events,is widely used in mini-mally invasive therapy.However,the studies on ultrasound-guided Lateral recess block(LRB)are limited,this is probably because there is no recognized standard method for ultrasound scanning.This study aimed to evaluate the effect of ultrasound-guided LRB in patients with lateral recess stenosis(LRS).CASE SUMMARY A 65-year-old patient complained of low back pain accompanied occasionally by pain and numbness in the left lower limb.Physical examination showed ten-derness on the spinous process and paraspinal muscles from L1 to S1,extensor hallucis longus and tibialis anterior weakness(muscle strength:4-),and a positive straight leg raising test in the left lower limb(60°).Magnetic resonance imaging showed L4–L5 disc degeneration with left LRS and nerve root entrapment.Subsequently,the patient was diagnosed with LRS.This patient was treated with a novel ultrasound-guided LRB approach.The patient’s symptoms significantly improved without any complications at 1 wk postoperatively and at the 3-month follow-up.CONCLUSION This is the first report on the LRS treatment with ultrasound-guided LRB from the contralateral spinous process along the inner side of the articular process by out-plane technique.Further studies are expected to investigate the efficacy and safety of ultrasound-guided LRB for patients with LRS.展开更多
In this paper,we reconstruct strongly-decaying block sparse signals by the block generalized orthogonal matching pursuit(BgOMP)algorithm in the l2-bounded noise case.Under some restraints on the minimum magnitude of t...In this paper,we reconstruct strongly-decaying block sparse signals by the block generalized orthogonal matching pursuit(BgOMP)algorithm in the l2-bounded noise case.Under some restraints on the minimum magnitude of the nonzero elements of the strongly-decaying block sparse signal,if the sensing matrix satisfies the the block restricted isometry property(block-RIP),then arbitrary strongly-decaying block sparse signals can be accurately and steadily reconstructed by the BgOMP algorithm in iterations.Furthermore,we conjecture that this condition is sharp.展开更多
Seismic attenuation is a fundamental property of the Earth's media.Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied.In this stud...Seismic attenuation is a fundamental property of the Earth's media.Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied.In this study,we collected 108,399 waveforms of 11,517 local small earthquakes with magnitudes between 1.5 and 3.5 from January 2014 to September 2021 in the Sichuan-Yunnan region and its adjacent areas.We employed an envelope inversion technique for separating the intrinsic and scattering attenuations of the S coda wave,and obtained the intrinsic and scattering attenuation structures for frequencies between 0.25 and 8.00 Hz.The attenuation structures correlate well with the geological units,and some major faults mark the attenuation variations where historic large earthquakes have occurred.The regional average attenuation shows a negative frequency dependence.The average scattering attenuation has a faster descending rate than the average intrinsic attenuation,and is dominant at low frequencies,while at high frequencies the average intrinsic attenuation is stronger.The lateral variation in the intrinsic attenuation is consistent with the variation in heat flow,the scattering attenuation may be related to the scatter distribution and size.The total attenuation is consistent with the previous studies in this region,and the separate intrinsic and scattering attenuation may be useful in understanding regional tectonics and important in earthquake prevention and disaster reduction.展开更多
Correction to:Nuclear Science and Techniques(2024)35:145 https://doi.org/10.1007/s41365-024-01517-y In this article the author’s name Wan-Bing He was incorrectly written as Wan-Bin He.The original article has been co...Correction to:Nuclear Science and Techniques(2024)35:145 https://doi.org/10.1007/s41365-024-01517-y In this article the author’s name Wan-Bing He was incorrectly written as Wan-Bin He.The original article has been corrected.展开更多
A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or m...A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or missing.Relatively benign Wenckebach type Ⅰ AVB is often misdiagnosed as Mobitz type Ⅱ which is an indication for a pacemaker.Review of the published reports indicates that Mobitz type II AVB does not occur during sleep when it is absent in the awake state.Conclusion:There is no proof that sleep is associated with Mobitz type Ⅱ AVB.展开更多
基金supported by National Natural Science Foundation of China Projects(42074065)Basic Research Operation Expenses of the Institute of Earthquake Prediction,China Earthquake Administration(2021IEF0103)。
文摘The Sichuan-Yunnan Block(SYB)is located at the SE margin of the Qinghai-Tibetan Plateau(TP).Under the influence of the southeastward movement of material originated from the TP,intense crustal deformation,frequent seismic activity,and complex geological structures are observed in the SYB.The Lijiang-Xiaojinhe fault(LXF)goes through the central part of the SYB,dividing it into two blocks from north to south,and forming an intersecting fault system with the surrounding faults.This paper firstly introduces the morphology and the nature of the LXF,the distribution of the regional surface displacements and the focal mechanisms,and then analyzes the medium deformation and the effects of faults.Moreover,according to the regional tectonics and geophysical patterns,the paper discusses the characteristics of the north-south blocks of the SYB and the abrupt change of deep structure along the LXF zone.Since seismic anisotropy is an essential property for detecting crustal stress,deep structures and dynamical mechanisms,this paper is dedicated to the advances in seismic anisotropy at different depths and different scales in the study area.There are noteworthy differences in the anisotropic features between the north part and the south part of the SYB,possibly associated with a clear boundary adjacent to the LXF.Such phenomenon suggests some close correlation between anisotropic zoning boundary and the LXF,although this boundary is not consistent with the LXF in strike.The results from the deformation of the crust and the upper mantle elucidate the distribution patterns of the crust-mantle coupling in the north part and the crustmantle decoupling in the south part,even though this conclusion needs to be further verified by more studies.Presently,the scientific understanding of the deep tectonics and the media deformation around the“generalized”LXF i.e.the LXF with the Jinpingshan fault on its eastern side,is still insufficient,and related equivocal topics deserve more in-depth studies.
基金supported by the National Natural Science Foundation of China (NSFC, grant number U2039207)。
文摘The central-southern part of the eastern border of the Sichuan-Yunnan rhombic block provides the research strategy of ‘trade space for time' with an interesting fault system, where the segments have similar focal mechanisms and cover almost continuous spectra of elapse rates. We experiment to study the seismological characteristics of different segments with different elapse rates. We employed the de-clustered earthquake catalog for the calculation of b values for each segment. The analysis revealed that different segments have similar b values,which implies that, although different segments have different periods of earthquake recurrence, the 'natural time' for the whole fault system elapses with a homogeneous pace. We extended the earthquake potential score(EPS)for nowcasting earthquakes to a quasi-EPS(q EPS). It is found that q EPS increases with the increase of elapse rates,albeit for those fault segments whose elapse rates have exceeded 1, q EPS may better reflect the seismic hazard.
基金Foundation item: State Key Basic research and Development Project from Ministry of Science and Technology of China (2004cb418406)National Natural Science Foundation of China (40521002).
文摘Harvard Centroid Moment Tensor （CMT） solutions for earthquakes from 1977 to 2004 showed that the stress fields are obviously different in northwestern Sichuan sub-block （NWSSB）, western parts of Central Yunnan sub-block （CYSB） and eastern part of CYSB. The characteristics of the mean stress fields in these three regions are obtained by fitting to CMT solutions. The stress state in NWSSB is characterized by its sub-horizontal tensile principal axis of stress （T axis） in roughly N-S direction and west dipping compressive principal axis of stress （P axis）; the one in western part of CYSB is characterized by its ENE dipping T axis and sub-horizontal medium principal axis of stress （B axis） in roughly N-S direction; the one in eastern part of CYSB is characterized by its sub-horizontal P axis in roughly NNW-SSE direction and sub-horizontal T axis in roughly WSW-ENE direction. Finite element method simulation clearly shows that the Indian Plate imposes great extrusion on Sichuan-Yunnan rhombic block （SYRB） near Assam massif. The value of the simulated compressive principal stress decreases with the distance from Assam massif. The simulated directions of the T axes in SYRB form annular distribution encir cling Assam. For a homogeneous elastic medium with free boundary conditions on the top and bottom surfaces as well as the displacement boundary conditions derived from the GPS observations on the lateral boundaries, the computation results are consistent with the Harvard CMT solutions in NWSSB and western part of CYSB, while inconsistent with the Harvard CMT solutions in eastern part of CYSB. The inconsistency in eastern part of CYSB can be reduced when it includes inhomogeneous elastic media. The stress states in NWSSB and western part of CYSB revealed by the Harvard CMT solutions are not local, which are mainly controlled by the boundary force on the whole region. On the other hand, the stress state in eastern part of CYSB given by the Harvard CMT solutions is local, which may be affected by local topography, material inhomogeneity, and the drag force underneath.
基金funded by Study on the Optimal Time Window of Single Azimuth Angle,the Three-in-one Project of Earthquake Monitoring,Prediction and Scientific Research of China Earthquake Administration(CEA-JC/3JH-162305)the Special Training Project for Youth Talents for Seismic Network,China Earthquake Administration(20150422)
文摘Based on the seismic station data sets from Sichuan and Yunnan provinces,we employed a multi-step seismic location method( Hypo2000 + Velest + HypoDD) to precisely locate the 7,787 earthquakes that occurred during 2010-2015 along the eastern boundaries of the Sichuan-Yunnan rhombic block,namely from southern Dawu to the Qiaojia segment.The final results show that location precision is greatly advanced and epicenter distribution exhibits good consistency with the linear distribution of the seismic faults. Earthquake distribution is quite intensive at the intersection region in the southern segment of the Xianshuihe fault,the Anninghe fault zone,the Xiaojinhe fault zone and the Daliangshan fault zone to the east. The depth profile of seismicity shows a clear stepwise activity along the active seismic fault zones. The profile crossing the faults of the Xianshuihe,Anninghe,and Daliangshan presents a complex interaction among faults near the multiple faults intersection region,Shimian,where the earthquakes are obviously divided into two groups in depth. Earthquakes are very rare at the depth of 15km-20 km,which is consistent with the region of the plastic rheology between 14km-19 km calculated by Zhu Ailan et al.,( 2005).
文摘Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation is slowing down along the northern segment and increasing along the southern segment. Each fault has different features of deformation. The horizontal deformation is mainly characterized by left-lateral strike-slip. The rate of vertical deformation is less than that of the horizontal deformation. The faults have the feature of upper wall uplifting alternated with descending. The anomaly changes of crustal deformation at some sites are closely related to the seismicities near the sites.
基金supported by Basic Research Project of Institute of Earthquake Science,China Earthquake Administration (2011ES010102)
文摘Deformation characteristics of the Sichuan-Yunnan region during the two periods 1999--2007 and 2007--2009 are analyzed with a block deformation model and GPS velocity profiles. The results show that the direction of the principal compressive strain rate of the Northwest-Sichuan block - the Mid-Yunnan block - the Southwest-Yunnan block was characterized by a clockwise rotation from north to south. The Anninghe and the Zemuhe faults had some shear-strain accumulation. The southern segment of the Xiaojiang fault had mainly strike-slip movement, while the northern segment was mainly accumulating strain. The 2008 Ms8.0 Wenchuan earthquake had some influence on the mid-southern segment of the Lijiang-Xiaojinhe fault, the Anninghe fault and the Jinshajiang fault, but not the Zemuhe fault, the Xiaojiang fault and the Red River fault as much.
基金The authors wish to thank National Key R&D Program of China(Grant No.2022YFC308100)the National Nature Science Foundation of China(Grant Nos.42107172 and 42072303)for financial support.
文摘Primary toppling usually occurs in layered rock slopes with large anti-dip angles.In this paper,the block toppling evolution was explored using a large-scale centrifuge system.Each block column in the layered model slope was made of cement mortar.Some artificial cracks perpendicular to the block column were prefabricated.Strain gages,displacement gages,and high-speed camera measurements were employed to monitor the deformation and failure processes of the model slope.The centrifuge test results show that the block toppling evolution can be divided into seven stages,i.e.layer compression,formation of major tensile crack,reverse bending of the block column,closure of major tensile crack,strong bending of the block column,formation of failure zone,and complete failure.Block toppling is characterized by sudden large deformation and occurs in stages.The wedge-shaped cracks in the model incline towards the slope.Experimental observations show that block toppling is mainly caused by bending failure rather than by shear failure.The tensile strength also plays a key factor in the evolution of block toppling.The simulation results from discrete element method(DEM)is in line with the testing results.Tensile stress exists at the backside of rock column during toppling deformation.Stress concentration results in the fragmented rock column and its degree is the most significant at the slope toe.
基金the National Natural Science Foundation of China(Grant number 51771178)Shaanxi Outstanding Youth Fund project(Grant number 2021JC-45)+2 种基金Key international cooperation projects in Shaanxi Province(Grant number 2020KWZ-007)the Major Program of Science and Technology in Shaanxi Province(Grant number20191102006)Open Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body(Grant number 32115019)。
文摘The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various industries.The conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient protection.In the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly technique.The outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)film.The FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier capability.The Ce film connects the outer layer with the substrate,showing the transition effect.The corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling behavior.The synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.
基金Supported by the National Natural Science Foundation of China,No.82305380The Postdoctoral Research Program,West China Hospital,Sichuan University,No.2020HXBH018.
文摘BACKGROUND Ultrasound guide technology,which can provide real-time visualization of the needle tip and tissues and avoid many adverse events,is widely used in mini-mally invasive therapy.However,the studies on ultrasound-guided Lateral recess block(LRB)are limited,this is probably because there is no recognized standard method for ultrasound scanning.This study aimed to evaluate the effect of ultrasound-guided LRB in patients with lateral recess stenosis(LRS).CASE SUMMARY A 65-year-old patient complained of low back pain accompanied occasionally by pain and numbness in the left lower limb.Physical examination showed ten-derness on the spinous process and paraspinal muscles from L1 to S1,extensor hallucis longus and tibialis anterior weakness(muscle strength:4-),and a positive straight leg raising test in the left lower limb(60°).Magnetic resonance imaging showed L4–L5 disc degeneration with left LRS and nerve root entrapment.Subsequently,the patient was diagnosed with LRS.This patient was treated with a novel ultrasound-guided LRB approach.The patient’s symptoms significantly improved without any complications at 1 wk postoperatively and at the 3-month follow-up.CONCLUSION This is the first report on the LRS treatment with ultrasound-guided LRB from the contralateral spinous process along the inner side of the articular process by out-plane technique.Further studies are expected to investigate the efficacy and safety of ultrasound-guided LRB for patients with LRS.
基金supported by Natural Science Foundation of China(62071262)the K.C.Wong Magna Fund at Ningbo University.
文摘In this paper,we reconstruct strongly-decaying block sparse signals by the block generalized orthogonal matching pursuit(BgOMP)algorithm in the l2-bounded noise case.Under some restraints on the minimum magnitude of the nonzero elements of the strongly-decaying block sparse signal,if the sensing matrix satisfies the the block restricted isometry property(block-RIP),then arbitrary strongly-decaying block sparse signals can be accurately and steadily reconstructed by the BgOMP algorithm in iterations.Furthermore,we conjecture that this condition is sharp.
基金supported by the Fundamental Research Funds for the Institute of Earthquake Forecas-ting,China Earthquake Administration(No.2021IEF0603)the Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB21B32).
文摘Seismic attenuation is a fundamental property of the Earth's media.Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied.In this study,we collected 108,399 waveforms of 11,517 local small earthquakes with magnitudes between 1.5 and 3.5 from January 2014 to September 2021 in the Sichuan-Yunnan region and its adjacent areas.We employed an envelope inversion technique for separating the intrinsic and scattering attenuations of the S coda wave,and obtained the intrinsic and scattering attenuation structures for frequencies between 0.25 and 8.00 Hz.The attenuation structures correlate well with the geological units,and some major faults mark the attenuation variations where historic large earthquakes have occurred.The regional average attenuation shows a negative frequency dependence.The average scattering attenuation has a faster descending rate than the average intrinsic attenuation,and is dominant at low frequencies,while at high frequencies the average intrinsic attenuation is stronger.The lateral variation in the intrinsic attenuation is consistent with the variation in heat flow,the scattering attenuation may be related to the scatter distribution and size.The total attenuation is consistent with the previous studies in this region,and the separate intrinsic and scattering attenuation may be useful in understanding regional tectonics and important in earthquake prevention and disaster reduction.
文摘Correction to:Nuclear Science and Techniques(2024)35:145 https://doi.org/10.1007/s41365-024-01517-y In this article the author’s name Wan-Bing He was incorrectly written as Wan-Bin He.The original article has been corrected.
文摘A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or missing.Relatively benign Wenckebach type Ⅰ AVB is often misdiagnosed as Mobitz type Ⅱ which is an indication for a pacemaker.Review of the published reports indicates that Mobitz type II AVB does not occur during sleep when it is absent in the awake state.Conclusion:There is no proof that sleep is associated with Mobitz type Ⅱ AVB.
