In this paper, the common heat source model of point and linear heat source in the numerical simulation of electron beam welding （EBW） were summarized and introduced. The combined point-linear heat source model was ...In this paper, the common heat source model of point and linear heat source in the numerical simulation of electron beam welding （EBW） were summarized and introduced. The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape. The model parameters were put forward and regulated in the combined model, which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr. Based on the combined model, the welding temperature fields of EBW were investigated. The results show that the predicted weld shapes are conformable to those of the actual, the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.展开更多
The concept of shape factors of the fusion-solidification zone is proposed to describe the weld cross section geometry. According to these shape factors, the electron beam weld fusion-solidification zone is divided in...The concept of shape factors of the fusion-solidification zone is proposed to describe the weld cross section geometry. According to these shape factors, the electron beam weld fusion-solidification zone is divided into four typical shapes and the classification criterion for these typical shapes is suggested. An integrated parameter n, combining the line power density of electron beam and material thermal properties is proposed to describe the relative power input, and another integrated parameter n2 combing the accelerating voltage and focusing current is proposed to reflect the power distribution in the keyhole. A series of new expressions, which can reflect the influence of focusing current, accelerating voltage, beam current, and material thermal properties, are developed to predict the fusion-solidification zone shape based on experimental results nonlinear fitting of n1 and n2.展开更多
Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 alloy.Four typical shapes of the fusion-solidification zone were gained by appropriate welding processes.The shap...Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 alloy.Four typical shapes of the fusion-solidification zone were gained by appropriate welding processes.The shapes and dimensions of the fusion-solidification zone of TC4 titanium joints were apparently influenced by processing parameters,focusing state and power density distribution.Based on the analyses of processing parameters,focusing state and power density distribution,the integrated parameters of n1 and n2 were put forward,which represented the distribution and intensity of electron beam energy.And a series of the formulations are developed to predict the shape of fusion-solidification zone by the processing parameters.展开更多
The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and...The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and single-cell transcriptomics of human medial ganglionic eminence(hMGE),a pivotal source of cortical and subpallial INs,and built the trajectories of hMGE-derived cells during brain development.We identified spatiotemporally and molecularly segregated progenitor cell populations fated to produce distinct IN types.展开更多
Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide i...Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.展开更多
The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and...The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.展开更多
Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investiga...Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.展开更多
The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthqu...The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.展开更多
The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structur...The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structure in the upper crust and seismogenic tectonics in the Hefei segment of this fault, we collected phase velocity dispersion data of fundamental mode Rayleigh waves from ambient noise cross-correlation functions of ~400 temporal seismographs in an area of approximately 80 × 70 km along the fault zone. The period band of the dispersion data was ~0.5–10 s. We inverted for the upper crustal three-dimensional(3-D) shear velocity model with azimuthal anisotropy from the surface to 10 km depth by using a 3-D direct azimuthal anisotropy inversion method. The inversion result shows the spatial distribution characteristics of the tectonic units in the upper crust. Additionally, the deformation of the Tan-Lu Fault Zone and its conjugated fault systems could be inferred from the anisotropy model. In particular, the faults that have remained active from the early and middle Pleistocene control the anisotropic characteristics of the upper crustal structure in this area. The direction of fast axes near the fault zone area in the upper crust is consistent with the strike of the faults, whereas for the region far away from the fault zone, the direction of fast axes is consistent with the direction of the regional principal stress caused by plate movement. Combined with the azimuthal anisotropy models in the deep crust and uppermost mantle from the surface wave and Pn wave, the different anisotropic patterns caused by the Tan-Lu Fault Zone and its conjugated fault system nearby are shown in the upper and lower crust. Furthermore,by using the double-difference method, we relocated the Lujiang earthquake series, which contained 32 earthquakes with a depth shallower than 10 km. Both the Vs model and earthquake relocation results indicate that earthquakes mostly occurred in the vicinity of structural boundaries with fractured media, with high-level development of cracks and small-scale faults jammed between more rigid areas.展开更多
High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.Hi...High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.展开更多
As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during min...As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during mining to decrease the min-ing workface temperature while also developing geothermal energy.This method is called the co-exploitation of mine and geothermal energy(CMGE).The geothermal development may precipitate the large-scale failure of the nearby fault zone during the mining process.However,the evolution of shear slide and shear failure of fault under geothermal production/rein-jection during mining is missing.Therefore,a fully-coupled hydraulic mechanism(HM)double-medium model for CMGE was developed based on the measured data of the Chensilou mine.A comparative analysis of the mechanical response of fault between CMGE and single mining was conducted.The disturbance of geothermal production pressure and reinjection pressure under mining on fault stability were respectively expounded.The results indicate that:(1)The disturbance of geo-thermal reinjection amplifies the disturbance of mining on fault stability.The amplified effect resulted in a normal stress drop of the fault,further leading to a substantial increase in shear slide distance,failure area,and cumulative seismic moment of fault compared with the single mining process.(2)As the distance of reinjection well to the fault decreases,the fault failure intensity increases.Setting the production well within the fault is advantageous for controlling fault stability under CMGE.(3)The essence of the combined disturbance of CMGE on the nearby fault is the overlay of tensile stress disturbance on the fault rock mass of the mining and geothermal reinjection.Though the geothermal reinjection causes a minor normal stress drop of fault,it can result in a more serious fault failure under CMGE.This paper supplies a significant gap in understanding thenearby faults failure under CMGE.展开更多
The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velo...The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.展开更多
Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. Thi...Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.展开更多
As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under ...As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under the action of the NWW-approximately EW strike-slip structures in the metallogenic province.The R1 black/fracture zone has a close relationship with ore forming;however,the mechanism of the rock-and ore-controlling action of the structural system remains unclear.Based on a detailed analysis of the tectonite-mineralized alteration lithofacies of the R1 black/fracture zone,the tectonite-mineralized alteration lithofacies zones can be divided into four types in succession outward from the Pb-Zn mineralization center(F_(5),F_(100),and other faults),i.e.,(1)the brecciated and stockwork-like Pb-Zn mineralization-complex breccia facies zone;(2)the stockwork-like Pb-Zn mineralization-simple breccia and cataclasite facies zone;(3)the veined pyrite-sulfide-dolomitic cataclasite facies zone;(4)the fine-veined calcite-black carbonized dolomite facies zone.With the evolution of the ore-forming fluid,the homogenization temperature decreases from Zone 1 to Zone 4;the salinity increases from Zone 1 to Zone 2 and then it decreases from Zones 3 and 4.The fluid density shows little change overall.The contents of Zn,Pb,Cu,Ga,Ge,Cd,Ag,and other metallogenic elements,Zn/Pb ratio,and CaO/MgO mole ratio decrease gradually from Zone 1 to Zone 4,and the REE fractionation,calcilization,silicification,and pyritization enhance gradually from Zone 1 to Zone 4.This series of changes is the product of diapirism(cryptoexplosion)of strike-slip structures and the black/fracture zone,among which the second-order structures derived from NWW-approximately EW-striking dextral shear-tension faults F_(1)and F_(15)control the brecciated and stockwork-like Pb-Zn mineralized complex breccia facies zones and the stockwork-like Pb-Zn mineralized simple breccia and cataclasite facies zones.Therefore,this paper establishes the zoning mode of tectonite-mineralized alteration lithofacies of the black/fracture zone and proposes that Zones 1 and 2 provide important prospecting criteria.展开更多
AIM:To observe the effect of the plus power ring zone(PPRZ)area and distribution on myopia progression.METHODS:This retrospective study enrolled 137 pre-teens aged 8-12 at Taiyuan Aier Eye Hospital between 2019 and 20...AIM:To observe the effect of the plus power ring zone(PPRZ)area and distribution on myopia progression.METHODS:This retrospective study enrolled 137 pre-teens aged 8-12 at Taiyuan Aier Eye Hospital between 2019 and 2021.They were fitted with Ortho-K lenses for the first time due to refractive error,with a one-year follow-up period.To indicate the peripheral plus ring zone overlapping with the pupil zone(PPROPZ)accompanying PPRZ,participants were divided based on the PPROPZ to PPRZ ratio.The experimental group had 103 eyes with a PPROPZ to PPRZ ratio of≥0.2,and the control group had 103 eyes with a ratio of<0.2.Participants had a spherical diopter in the range of-6.00 D to-0.75 D,against-the-rule astigmatism less than 1.00 D,with-the-rule astigmatism less than 1.50 D,and corneal curvatures of 39.00 D to 46.00 D.They had a stable best corrected visual acuity of 0.10 LogMAR(20/25)or better when wearing orthokeratology(Ortho-K)lenses.PPRZ and PPROPZ were measured using ImageJ;corneal topography assessed corneal-related parameters,and an optical biometer measured the axial length of the eyes pre and post-one years of lens wear.RESULTS:Changes in axial length elongation were found to decrease when either the PPRZ(P<0.01)or PPROPZ(P<0.001)was increased significantly.The axial length growth was faster in the control group(0.37±0.2 mm)than in the experimental group(0.21±0.11 mm).Furthermore,we found that a larger horizontal visible iris diameter(HVID)corresponded to slower axial growth of the eye.In contrast,axial length growth showed no correlation with surface regularity index(SRI),surface asymmetry index(SAI),flat keratometry value(K_(f)),steep keratometry value(K_(s)).CONCLUSION:For orthokeratology,wearers with larger PPROPZ to PPRZ ratio usually experiences a reduction in axial length growth.The PPRZ and PPROPZ are negatively correlated with the axial length.Our findings provide a recommendation and methods for studying the myopia control mechanism through Ortho-K lenses.展开更多
The structures of the mantle transition zone(MTZ)are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones.Here by dense near-source S...The structures of the mantle transition zone(MTZ)are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones.Here by dense near-source SdP sampling from a large global dataset,we image topographies of transition zone discontinuities such as the 410-km and 660-km discontinuities(410 and 660)beneath the Kamchatka and conduct cross-section comparisons with the seismicity.Compared with the IASP91 model,the 410 exhibits apparent uplifts of 45-65 km with an average of 55 km in a horizontal width of~130 km,corresponding to lowtemperature anomalies of 750-1083 K with an average of 916 K.In contrast,the 660 shows depressions of 15-37 km with an average of 25 km together with downward deflections in a width of~260 km,implying low-temperature anomalies of 161-397 K with an average of 268 K.Thus,we confirm a thickened MTZ with a thickness of 325-345 km around the cold descending Pacific slab.We suggest that topographic patterns of transition zone discontinuities imply a Pacific slab that has been significantly heated in the MTZ with broadened thermal effects on the 660.When considered along with other studies,we infer that the slab is possibly heated by hot mantle flows around the torn slab window extended to at least the MTZ range,thus inducing variations in thermal and rheological properties of the slab.Our seismic results can provide more insight into slab dynamics in the northwestern Pacific.展开更多
AIM:To investigate the impact of preoperative anterior corneal topographic parameters on the morphology of the postoperative effective optical zone(EOZ)in patients undergoing keratorefractive lenticule extraction(KLEx...AIM:To investigate the impact of preoperative anterior corneal topographic parameters on the morphology of the postoperative effective optical zone(EOZ)in patients undergoing keratorefractive lenticule extraction(KLEx)and wavefront-guided LASIK(WG-LASIK).METHODS:This retrospective study included 310 eyes from patients who underwent either KLEx(via small incision lenticule extraction,171 eyes)or WG-LASIK(139 eyes).Patients were stratified into subgroups based on the median values of spherical equivalent(SE)and anterior corneal topographic parameters.Postoperative EOZ parameters were measured 1mo after surgery and compared across subgroups.Correlation analysis and multivariable linear regression analysis were performed to explore the associations between preoperative anterior corneal topographic parameters and EOZ parameters.RESULTS:A total of 310 eyes were included(KLEx:171 eyes from 88 patients;WG-LASIK:139 eyes from 82 patients).The mean age was 30.65±5.67y in the KLEx cohort and 29.06±5.94y in the WG-LASIK cohort.In the KLEx cohort,SE,preoperative mean keratometry(Km),steep keratometry(K2),and anterior corneal astigmatism(K2-K1)were positively correlated with the postoperative optical zone reduction ratio(RR=EOZ/planned optical zone×100%;all P<0.01).Multivariable regression identified SE[β=0.027,95%confidence interval(CI):0.022-0.032,P<0.001],Km(β=0.009,95%CI:0.002-0.016,P=0.014),and anterior corneal astigmatism(β=0.031,95%CI:0.013-0.049,P<0.001)as significant predictors of RR(R²=0.456,P<0.001).In the WG-LASIK cohort,SE was positively correlated with RR(P<0.01);K2 and anterior corneal astigmatism were positively correlated with both RR(P<0.05)and EOZ eccentricity(P<0.01).Multivariable regression showed SE(β=0.015,95%CI:0.007-0.023,P<0.001)and anterior corneal astigmatism(β=0.029,95%CI:0.012-0.047,P=0.001)were significant predictors of RR(R²=0.121,P<0.001).CONCLUSION:Preoperative anterior corneal topographic parameters,particularly anterior corneal astigmatism,significantly affect postoperative EOZ morphology in both KLEx and WG-LASIK.Additionally,Km is a predictor of EOZ reduction specifically in KLEx.展开更多
The widespread variation of focal depths and fault plane solutions observed in the Hindukush region depicts continuous deformation along the Indian-Eurasian collision zone.For period of twelve years i.e.from 2010 to 2...The widespread variation of focal depths and fault plane solutions observed in the Hindukush region depicts continuous deformation along the Indian-Eurasian collision zone.For period of twelve years i.e.from 2010 to 2022,a total of 89 intermediate-depth earthquakes of magnitude(Mw)≥5.5 of the Hindukush Region were considered,relocated using both regional and tele seismic data with 90 per cent confidence limits of less than 20 km.Two distinct seismic activity clusters:First one at a deeper depth and second at a shallower depth having different P-axes were observed that verifies the internal structure and geometry of Hindukush zone as suggested in previous studies.Beneath the Hindukush collision zone,there exists a complex pattern of deformation,arising from a combination of compression,tension,shearing and necking states due to an unusual and a rare case of subduction that is not from oceanic plate.The Hindukush seismic zone extends from 70 to 300 km depth and mostly strikes east-west and then turns northeast.The relocated seismicity by merging data of seismic network close to Hindukush along with international data shows that the Hindukush zone may be divided vertically into upper and lower slabs separated by a gap at about 150 km depth at which strike and dip directions change sharply with significant structural changes.Seismicity rate is higher in the lower part of Hindukush,having large magnitude events in a small volume below 180 km forming complex pattern of source mechanisms.Contrary in upper part seismicity rate is lower and scattered.The Global CMT(Global Centroid-Moment-Tensor Project)source mechanisms of intermediate depth earthquakes have a systematic pattern of reverse faulting with the vertical T-axes,while shallow events do not have such pattern.The vertical T-axes of the intermediate-depth events may be attributed to negative buoyancy caused by subduction of the cold and denser slab.展开更多
The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron micr...The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron microscopy(SEM)with electron backscatter diffraction(EBSD)measurements at the surface and core regions.The findings indicate that FSW produced grain refinement where the mean grain size decreases from 19μm(base metal)to 5.1 and 3.5μm at the surface and core regions,respectively.The c-axis of the grains at the surface region was aligned with the normal direction(<0001>//ND)due to the additional strain of the tool shoulder.In contrast,the core region shows a typical shear texture,where the c-axis tends to be oriented parallel to the welding direction(<0001>//WD).The Vickers microhardness mapping across the SZ revealed that the core region was soften than the surface region due to the dynamic recrystallization and texture weakening.The microstructure of the SZ remains principally deformed after annealing treatment except for the development of massive Mg_(17)Al_(12)precipitates and the abnormal grain growth of a few grains with<11-20>//WD orientation at the upper side of the surface region.The c-axis of the grains at the surface region was tilted about 10°toward WD,while an inclined<0001>//WD orientation about 30°from WD was developed at the core region.Consequently,the distribution of microhardness values across the SZ was more heterogeneous than the FSW sample.The results were discussed in the light of grain boundary misorientation,dislocation density and the pinning effect of Mg_(17)Al_(12)precipitates.Additionally,Schmid factor analysis was used to examine the activation of the basal slip mode to characterize the associated mechanical response.展开更多
基金co-supported by the National Basic Research Program (No.61362)the National Natural Science Foundation of China(No. 50935008 and 10902113)Science Foundation of Aeronautics (No. 2010ZE25006)
文摘In this paper, the common heat source model of point and linear heat source in the numerical simulation of electron beam welding （EBW） were summarized and introduced. The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape. The model parameters were put forward and regulated in the combined model, which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr. Based on the combined model, the welding temperature fields of EBW were investigated. The results show that the predicted weld shapes are conformable to those of the actual, the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.
文摘The concept of shape factors of the fusion-solidification zone is proposed to describe the weld cross section geometry. According to these shape factors, the electron beam weld fusion-solidification zone is divided into four typical shapes and the classification criterion for these typical shapes is suggested. An integrated parameter n, combining the line power density of electron beam and material thermal properties is proposed to describe the relative power input, and another integrated parameter n2 combing the accelerating voltage and focusing current is proposed to reflect the power distribution in the keyhole. A series of new expressions, which can reflect the influence of focusing current, accelerating voltage, beam current, and material thermal properties, are developed to predict the fusion-solidification zone shape based on experimental results nonlinear fitting of n1 and n2.
文摘Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 alloy.Four typical shapes of the fusion-solidification zone were gained by appropriate welding processes.The shapes and dimensions of the fusion-solidification zone of TC4 titanium joints were apparently influenced by processing parameters,focusing state and power density distribution.Based on the analyses of processing parameters,focusing state and power density distribution,the integrated parameters of n1 and n2 were put forward,which represented the distribution and intensity of electron beam energy.And a series of the formulations are developed to predict the shape of fusion-solidification zone by the processing parameters.
文摘The number and diversity of inhibitory neurons(INs)increased substantially during mammalian brain evolution.However,the generative mechanisms of the vast repertoire of human INs remain elusive.We performed spatial and single-cell transcriptomics of human medial ganglionic eminence(hMGE),a pivotal source of cortical and subpallial INs,and built the trajectories of hMGE-derived cells during brain development.We identified spatiotemporally and molecularly segregated progenitor cell populations fated to produce distinct IN types.
基金supported by the National Key R&D Program of China(No.2021YFA1501002)Thousand Talents Program for Distinguished Young Scholars.X.Li thanks the National Natural Science Foundation of China(No.22309021).
文摘Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.
基金supported by the Major Program of the National Natural Science Foundation of China (Grant No.42090055)the National Major Scientific Instruments and Equipment Development Projects of China (Grant No.41827808)the National Nature Science Foundation of China (Grant No.42207216).
文摘The strength of the sliding zone soil determines the stability of reservoir landslides.Fluctuations in water levels cause a change in the seepage field,which serves as both the external hydrogeological environment and the internal component of a landslide.Therefore,considering the strength changes of the sliding zone with seepage effects,they correspond with the actual hydrogeological circumstances.To investigate the shear behavior of sliding zone soil under various seepage pressures,24 samples were conducted by a self-developed apparatus to observe the shear strength and measure the permeability coefficients at different deformation stages.After seepage-shear tests,the composition of clay minerals and microscopic structure on the shear surface were analyzed through X-ray and scanning electron microscope(SEM)to understand the coupling effects of seepage on strength.The results revealed that the sliding zone soil exhibited strain-hardening without seepage pressure.However,the introduction of seepage caused a significant reduction in shear strength,resulting in strain-softening characterized by a three-stage process.Long-term seepage action softened clay particles and transported broken particles into effective seepage channels,causing continuous damage to the interior structure and reducing the permeability coefficient.Increased seepage pressure decreased the peak strength by disrupting occlusal and frictional forces between sliding zone soil particles,which carried away more clay particles,contributing to an overhead structure in the soil that raised the permeability coefficient and decreased residual strength.The internal friction angle was less sensitive to variations in seepage pressure than cohesion.
基金supported by the Fundamental Research Funds of the Institute of Geomechanics(DZLXJK202401)the National Natural Science Foundation of China(42177172,U2244226,42172255)+1 种基金the China Geological Survey Project(DD20230538)Deep Earth Probe and Mineral Resources ExplorationNational Science and Technology Major Project(2024ZD1000500)。
文摘Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.
基金funded by the National Key R&D Program of China (Grant No. 2021YFC3000704)the National Natural Science Foundation of China (Grant No. 42125401)the Central Public-interest Scientific Institution Basal Research Fund (Grant No. CEAIEF20240401)。
文摘The Anninghe–Zemuhe Fault and the Xiaojiang Fault are critical active faults along the middle-eastern boundary of the South Chuan–Dian Block. Many researchers have identified these faults as potential strong-earthquake risk zones. In this study, we leveraged a dense seismic array to investigate the high-resolution shallow crust shear wave velocity(Vs) structure beneath the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone, one of the most complex parts of the eastern boundary of the South Chuan–Dian Block. We analyzed the distribution of microseismic events detected between November 2022 and February 2023 based on the fine-scale Vs model obtained. The microseismicity in the study region was clustered into three groups, all spatially related to major faults in this region. These microseismic events indicate near-vertical fault planes, consistent with the fault geometry revealed by other researchers.Moreover, these microseismic events are influenced by the impoundment of the downstream Baihetan Reservoir and the complex tectonic stress near the junction of the Zemuhe Fault Zone and the Xiaojiang Fault Zone. The depths of these microseismic events are shallower in the junction zone, whereas moving south along the Xiaojiang Fault Zone, the microseismic events become deeper.Additionally, we compared our fine-scale local Vs model with velocity models obtained by other researchers and found that our model offers greater detail in characterizing subsurface heterogeneity while demonstrating improved reliability in delineating fault systems.
基金financially supported by the National Key Research and Development Program of China (2022YFC3005600)the Foundation of the Anhui Educational Commission (2023AH051198)+1 种基金the National Natural Science Foundation of China (42125401 and 42104063)the Joint Open Fund of Mengcheng National Geophysical Observatory (MENGO-202201)。
文摘The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structure in the upper crust and seismogenic tectonics in the Hefei segment of this fault, we collected phase velocity dispersion data of fundamental mode Rayleigh waves from ambient noise cross-correlation functions of ~400 temporal seismographs in an area of approximately 80 × 70 km along the fault zone. The period band of the dispersion data was ~0.5–10 s. We inverted for the upper crustal three-dimensional(3-D) shear velocity model with azimuthal anisotropy from the surface to 10 km depth by using a 3-D direct azimuthal anisotropy inversion method. The inversion result shows the spatial distribution characteristics of the tectonic units in the upper crust. Additionally, the deformation of the Tan-Lu Fault Zone and its conjugated fault systems could be inferred from the anisotropy model. In particular, the faults that have remained active from the early and middle Pleistocene control the anisotropic characteristics of the upper crustal structure in this area. The direction of fast axes near the fault zone area in the upper crust is consistent with the strike of the faults, whereas for the region far away from the fault zone, the direction of fast axes is consistent with the direction of the regional principal stress caused by plate movement. Combined with the azimuthal anisotropy models in the deep crust and uppermost mantle from the surface wave and Pn wave, the different anisotropic patterns caused by the Tan-Lu Fault Zone and its conjugated fault system nearby are shown in the upper and lower crust. Furthermore,by using the double-difference method, we relocated the Lujiang earthquake series, which contained 32 earthquakes with a depth shallower than 10 km. Both the Vs model and earthquake relocation results indicate that earthquakes mostly occurred in the vicinity of structural boundaries with fractured media, with high-level development of cracks and small-scale faults jammed between more rigid areas.
基金National Key Research and Development Program of China(2023YFC2907904)National Natural Science Foundation of China(52374364)。
文摘High-purity indium finds extensive application in the aerospace,electronics,medical,energy,and national defense sectors.Its purity and impurity contents significantly influence its performance in these applications.High-purity indium was prepared by combining zone refining with vacuum distillation.Results show that the average removal efficiency of impurity Sb can approach 95%,while the removal efficiency of impurities Sn and Bi can reach over 95%,and the removal efficiency of Si,Fe,Ni,and Pb can reach over 85%.Ultimately,the amount of Sn and Sb impurities is reduced to 2.0 and 4.1μg/kg,respectively,and that of most impurities,including Fe,Ni,Pb,and Bi,is reduced to levels below the instrumental detection limit.The average impurity removal efficiency is 90.9%,and the indium purity reaches 7N9.
基金supported by the Key Project of the National Natural Science Foundation of China(U23B2091)the National Key R&D Program of China(2022YFC2905600)+1 种基金the Youth Project of the National Natural Science Foundation of China(52304104 and 52404157)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20240825).
文摘As the mine depth around the world increases,the temperature of the surrounding rock of the mining workface increases significantly.To control the heat hazards,the hot water in the mining floor is developed during mining to decrease the min-ing workface temperature while also developing geothermal energy.This method is called the co-exploitation of mine and geothermal energy(CMGE).The geothermal development may precipitate the large-scale failure of the nearby fault zone during the mining process.However,the evolution of shear slide and shear failure of fault under geothermal production/rein-jection during mining is missing.Therefore,a fully-coupled hydraulic mechanism(HM)double-medium model for CMGE was developed based on the measured data of the Chensilou mine.A comparative analysis of the mechanical response of fault between CMGE and single mining was conducted.The disturbance of geothermal production pressure and reinjection pressure under mining on fault stability were respectively expounded.The results indicate that:(1)The disturbance of geo-thermal reinjection amplifies the disturbance of mining on fault stability.The amplified effect resulted in a normal stress drop of the fault,further leading to a substantial increase in shear slide distance,failure area,and cumulative seismic moment of fault compared with the single mining process.(2)As the distance of reinjection well to the fault decreases,the fault failure intensity increases.Setting the production well within the fault is advantageous for controlling fault stability under CMGE.(3)The essence of the combined disturbance of CMGE on the nearby fault is the overlay of tensile stress disturbance on the fault rock mass of the mining and geothermal reinjection.Though the geothermal reinjection causes a minor normal stress drop of fault,it can result in a more serious fault failure under CMGE.This paper supplies a significant gap in understanding thenearby faults failure under CMGE.
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology under Grant 2024yjrc64the National Key R&D Program of China under Grant 2018YFC1504102。
文摘The Longmenshan(LMS)fault zone is located at the junction of the eastern Tibetan Plateau and the Sichuan Basin and is of great significance for studying regional tectonics and earthquake hazards.Although regional velocity models are available for the LMS fault zone,high-resolution velocity models are lacking.Therefore,a dense array of 240 short-period seismometers was deployed around the central segment of the LMS fault zone for approximately 30 days to monitor earthquakes and characterize fine structures of the fault zone.Considering the large quantity of observed seismic data,the data processing workflow consisted of deep learning-based automatic earthquake detection,phase arrival picking,and association.Compared with the earthquake catalog released by the China Earthquake Administration,many more earthquakes were detected by the dense array.Double-difference seismic tomography was adopted to determine V_(p),V_(s),and V_(p)/V_(s)models as well as earthquake locations.The checkerboard test showed that the velocity models have spatial resolutions of approximately 5 km in the horizontal directions and 2 km at depth.To the west of the Yingxiu–Beichuan Fault(YBF),the Precambrian Pengguan complex,where most of earthquakes occurred,is characterized by high velocity and low V_(p)/V_(s)values.In comparison,to the east of the YBF,the Upper Paleozoic to Jurassic sediments,where few earthquakes occurred,show low velocity and high V_(p)/V_(s)values.Our results suggest that the earthquake activity in the LMS fault zone is controlled by the strength of the rock compositions.When the high-resolution velocity models were combined with the relocated earthquakes,we were also able to delineate the fault geometry for different faults in the LMS fault zone.
文摘Objective: The present research aims to determine if adherence to the Lewinnek safe zone, when exclusively considered, constitutes a pivotal element for ensuring stability in the context of total hip arthroplasty. This is done by examining the acetabular placement in instances of hip dislocation after total hip arthroplasty (THA). Methodology: The authors searched 2653 patient records from 2015 to 2022 looking for patients who had total hip arthroplasty at our facility. For the analysis, 23 patients were culled from 64 individuals who exhibited post-THA dislocations, employing a stringent exclusion criterion, and the resultant acetabular angulation and anteversion were quantified utilizing PEEKMED software (Peek Health S.A., Portugal) upon radiographic evidence. Results: Within the operational timeframe, from the cohort of 2653 subjects, 64 presented with at least a singular incident of displacement. Post-exclusion criterion enforcement, 23 patients were eligible for inclusion. Of these, 10 patients conformed to the safe zone demarcated by Lewinnek for both inclination and anteversion angles, while 13 exhibited deviations from the prescribed anteversion and/or inclination benchmarks. Conclusion: Analysis of the 23 patients reveals that 13 did not confirm to be in the safe zone parameters for anteversion and/or inclination, whereas 10 were within the safe zone as per Lewinnek’s guidelines. This investigative review, corroborated by extant literature, suggests that the isolated consideration of the Lewinnek safe zone does not suffice as a solitary protective factor. It further posits that additional variables are equally critical as acetabular positioning and mandate individual assessment.
基金funded by the programs of the National Natural Science Foundation(Nos.42172086,41572060,U1133602)the Program of‘Yunling Scholar’of Yunnan province(2014)+1 种基金the Projects of the Yunnan Engineering Laboratory of Mineral Resources Prediction and Evaluation(YM Lab)(2010)the Innovation Team of Yunnan Province and KMUST(2008,2012).
文摘As one of the typical deposits in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province,the Daliangzi Pb-Zn deposit has a close genetic relationship with the structural system of the black/fracture zone formed under the action of the NWW-approximately EW strike-slip structures in the metallogenic province.The R1 black/fracture zone has a close relationship with ore forming;however,the mechanism of the rock-and ore-controlling action of the structural system remains unclear.Based on a detailed analysis of the tectonite-mineralized alteration lithofacies of the R1 black/fracture zone,the tectonite-mineralized alteration lithofacies zones can be divided into four types in succession outward from the Pb-Zn mineralization center(F_(5),F_(100),and other faults),i.e.,(1)the brecciated and stockwork-like Pb-Zn mineralization-complex breccia facies zone;(2)the stockwork-like Pb-Zn mineralization-simple breccia and cataclasite facies zone;(3)the veined pyrite-sulfide-dolomitic cataclasite facies zone;(4)the fine-veined calcite-black carbonized dolomite facies zone.With the evolution of the ore-forming fluid,the homogenization temperature decreases from Zone 1 to Zone 4;the salinity increases from Zone 1 to Zone 2 and then it decreases from Zones 3 and 4.The fluid density shows little change overall.The contents of Zn,Pb,Cu,Ga,Ge,Cd,Ag,and other metallogenic elements,Zn/Pb ratio,and CaO/MgO mole ratio decrease gradually from Zone 1 to Zone 4,and the REE fractionation,calcilization,silicification,and pyritization enhance gradually from Zone 1 to Zone 4.This series of changes is the product of diapirism(cryptoexplosion)of strike-slip structures and the black/fracture zone,among which the second-order structures derived from NWW-approximately EW-striking dextral shear-tension faults F_(1)and F_(15)control the brecciated and stockwork-like Pb-Zn mineralized complex breccia facies zones and the stockwork-like Pb-Zn mineralized simple breccia and cataclasite facies zones.Therefore,this paper establishes the zoning mode of tectonite-mineralized alteration lithofacies of the black/fracture zone and proposes that Zones 1 and 2 provide important prospecting criteria.
文摘AIM:To observe the effect of the plus power ring zone(PPRZ)area and distribution on myopia progression.METHODS:This retrospective study enrolled 137 pre-teens aged 8-12 at Taiyuan Aier Eye Hospital between 2019 and 2021.They were fitted with Ortho-K lenses for the first time due to refractive error,with a one-year follow-up period.To indicate the peripheral plus ring zone overlapping with the pupil zone(PPROPZ)accompanying PPRZ,participants were divided based on the PPROPZ to PPRZ ratio.The experimental group had 103 eyes with a PPROPZ to PPRZ ratio of≥0.2,and the control group had 103 eyes with a ratio of<0.2.Participants had a spherical diopter in the range of-6.00 D to-0.75 D,against-the-rule astigmatism less than 1.00 D,with-the-rule astigmatism less than 1.50 D,and corneal curvatures of 39.00 D to 46.00 D.They had a stable best corrected visual acuity of 0.10 LogMAR(20/25)or better when wearing orthokeratology(Ortho-K)lenses.PPRZ and PPROPZ were measured using ImageJ;corneal topography assessed corneal-related parameters,and an optical biometer measured the axial length of the eyes pre and post-one years of lens wear.RESULTS:Changes in axial length elongation were found to decrease when either the PPRZ(P<0.01)or PPROPZ(P<0.001)was increased significantly.The axial length growth was faster in the control group(0.37±0.2 mm)than in the experimental group(0.21±0.11 mm).Furthermore,we found that a larger horizontal visible iris diameter(HVID)corresponded to slower axial growth of the eye.In contrast,axial length growth showed no correlation with surface regularity index(SRI),surface asymmetry index(SAI),flat keratometry value(K_(f)),steep keratometry value(K_(s)).CONCLUSION:For orthokeratology,wearers with larger PPROPZ to PPRZ ratio usually experiences a reduction in axial length growth.The PPRZ and PPROPZ are negatively correlated with the axial length.Our findings provide a recommendation and methods for studying the myopia control mechanism through Ortho-K lenses.
基金supported by the Central Public-interest Scientific Institution Basal Research Fund(No.CEAIEF 20220201)the National Natural Science Foundation of China(Nos.42374113 and 42074101)the Central Publicinterest Scientific Institution Basal Research Fund(No.CEAIEF20230204).
文摘The structures of the mantle transition zone(MTZ)are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones.Here by dense near-source SdP sampling from a large global dataset,we image topographies of transition zone discontinuities such as the 410-km and 660-km discontinuities(410 and 660)beneath the Kamchatka and conduct cross-section comparisons with the seismicity.Compared with the IASP91 model,the 410 exhibits apparent uplifts of 45-65 km with an average of 55 km in a horizontal width of~130 km,corresponding to lowtemperature anomalies of 750-1083 K with an average of 916 K.In contrast,the 660 shows depressions of 15-37 km with an average of 25 km together with downward deflections in a width of~260 km,implying low-temperature anomalies of 161-397 K with an average of 268 K.Thus,we confirm a thickened MTZ with a thickness of 325-345 km around the cold descending Pacific slab.We suggest that topographic patterns of transition zone discontinuities imply a Pacific slab that has been significantly heated in the MTZ with broadened thermal effects on the 660.When considered along with other studies,we infer that the slab is possibly heated by hot mantle flows around the torn slab window extended to at least the MTZ range,thus inducing variations in thermal and rheological properties of the slab.Our seismic results can provide more insight into slab dynamics in the northwestern Pacific.
文摘AIM:To investigate the impact of preoperative anterior corneal topographic parameters on the morphology of the postoperative effective optical zone(EOZ)in patients undergoing keratorefractive lenticule extraction(KLEx)and wavefront-guided LASIK(WG-LASIK).METHODS:This retrospective study included 310 eyes from patients who underwent either KLEx(via small incision lenticule extraction,171 eyes)or WG-LASIK(139 eyes).Patients were stratified into subgroups based on the median values of spherical equivalent(SE)and anterior corneal topographic parameters.Postoperative EOZ parameters were measured 1mo after surgery and compared across subgroups.Correlation analysis and multivariable linear regression analysis were performed to explore the associations between preoperative anterior corneal topographic parameters and EOZ parameters.RESULTS:A total of 310 eyes were included(KLEx:171 eyes from 88 patients;WG-LASIK:139 eyes from 82 patients).The mean age was 30.65±5.67y in the KLEx cohort and 29.06±5.94y in the WG-LASIK cohort.In the KLEx cohort,SE,preoperative mean keratometry(Km),steep keratometry(K2),and anterior corneal astigmatism(K2-K1)were positively correlated with the postoperative optical zone reduction ratio(RR=EOZ/planned optical zone×100%;all P<0.01).Multivariable regression identified SE[β=0.027,95%confidence interval(CI):0.022-0.032,P<0.001],Km(β=0.009,95%CI:0.002-0.016,P=0.014),and anterior corneal astigmatism(β=0.031,95%CI:0.013-0.049,P<0.001)as significant predictors of RR(R²=0.456,P<0.001).In the WG-LASIK cohort,SE was positively correlated with RR(P<0.01);K2 and anterior corneal astigmatism were positively correlated with both RR(P<0.05)and EOZ eccentricity(P<0.01).Multivariable regression showed SE(β=0.015,95%CI:0.007-0.023,P<0.001)and anterior corneal astigmatism(β=0.029,95%CI:0.012-0.047,P=0.001)were significant predictors of RR(R²=0.121,P<0.001).CONCLUSION:Preoperative anterior corneal topographic parameters,particularly anterior corneal astigmatism,significantly affect postoperative EOZ morphology in both KLEx and WG-LASIK.Additionally,Km is a predictor of EOZ reduction specifically in KLEx.
文摘The widespread variation of focal depths and fault plane solutions observed in the Hindukush region depicts continuous deformation along the Indian-Eurasian collision zone.For period of twelve years i.e.from 2010 to 2022,a total of 89 intermediate-depth earthquakes of magnitude(Mw)≥5.5 of the Hindukush Region were considered,relocated using both regional and tele seismic data with 90 per cent confidence limits of less than 20 km.Two distinct seismic activity clusters:First one at a deeper depth and second at a shallower depth having different P-axes were observed that verifies the internal structure and geometry of Hindukush zone as suggested in previous studies.Beneath the Hindukush collision zone,there exists a complex pattern of deformation,arising from a combination of compression,tension,shearing and necking states due to an unusual and a rare case of subduction that is not from oceanic plate.The Hindukush seismic zone extends from 70 to 300 km depth and mostly strikes east-west and then turns northeast.The relocated seismicity by merging data of seismic network close to Hindukush along with international data shows that the Hindukush zone may be divided vertically into upper and lower slabs separated by a gap at about 150 km depth at which strike and dip directions change sharply with significant structural changes.Seismicity rate is higher in the lower part of Hindukush,having large magnitude events in a small volume below 180 km forming complex pattern of source mechanisms.Contrary in upper part seismicity rate is lower and scattered.The Global CMT(Global Centroid-Moment-Tensor Project)source mechanisms of intermediate depth earthquakes have a systematic pattern of reverse faulting with the vertical T-axes,while shallow events do not have such pattern.The vertical T-axes of the intermediate-depth events may be attributed to negative buoyancy caused by subduction of the cold and denser slab.
基金supported by the PHC-Tassili program No.24MDU114。
文摘The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron microscopy(SEM)with electron backscatter diffraction(EBSD)measurements at the surface and core regions.The findings indicate that FSW produced grain refinement where the mean grain size decreases from 19μm(base metal)to 5.1 and 3.5μm at the surface and core regions,respectively.The c-axis of the grains at the surface region was aligned with the normal direction(<0001>//ND)due to the additional strain of the tool shoulder.In contrast,the core region shows a typical shear texture,where the c-axis tends to be oriented parallel to the welding direction(<0001>//WD).The Vickers microhardness mapping across the SZ revealed that the core region was soften than the surface region due to the dynamic recrystallization and texture weakening.The microstructure of the SZ remains principally deformed after annealing treatment except for the development of massive Mg_(17)Al_(12)precipitates and the abnormal grain growth of a few grains with<11-20>//WD orientation at the upper side of the surface region.The c-axis of the grains at the surface region was tilted about 10°toward WD,while an inclined<0001>//WD orientation about 30°from WD was developed at the core region.Consequently,the distribution of microhardness values across the SZ was more heterogeneous than the FSW sample.The results were discussed in the light of grain boundary misorientation,dislocation density and the pinning effect of Mg_(17)Al_(12)precipitates.Additionally,Schmid factor analysis was used to examine the activation of the basal slip mode to characterize the associated mechanical response.
