The coarsening behavior of Cr precipitates in Cu-0.1Ag-0.5Cr alloy was investigated, and the effects of aging processes on the microstructure and properties were discussed. The results show that the radius for coheren...The coarsening behavior of Cr precipitates in Cu-0.1Ag-0.5Cr alloy was investigated, and the effects of aging processes on the microstructure and properties were discussed. The results show that the radius for coherent/semi-coherent transition of the Cr precipitates is determined from TEM micrographs as 1545nm. The calculated value of critical radius for a particle begining to lose coherency is about 12.5nm. The coherent (r<15nm) precipitates are found to coarsen and become semi-coherent during the passage of low-angle boundaries during recovery. The passage of high-angle boundaries through semi-coherent precipitates during recrystallization occurs by migration of the particle, resulting in the precipitates maintaining semi-coherent with the new grain.展开更多
Proper Orthogonal Decomposition （POD） provides a powerful modal transformation tool for stochastic dynamics. In this paper, coherency matrix-based proper orthogonal decomposition （CPOD） is presented as an innovati...Proper Orthogonal Decomposition （POD） provides a powerful modal transformation tool for stochastic dynamics. In this paper, coherency matrix-based proper orthogonal decomposition （CPOD） is presented as an innovative form of the POD based on cross power spectral density matrices. By introducing a discretizing scheme, the CPOD-based spectral representation method is obtained for use in stochastic simulation. Moreover, some criteria are proposed that allow the truncation order of CPOD to be conveniently determined. A numerical example to illustrate the application of the proposed method for the simulation of a wind velocity field is provided.展开更多
Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events ...Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events have demonstrated that the vertical components of ground motion sometimes govern the ultimate failure of structures. In this paper, a vertical coherency function model of spatial ground motion is proposed based on the Hao model and SMART 1 array records, and the validity of the model is demonstrated. The vertical coherency function model of spatial ground motion is also compared with the horizontal coherency function model, indicating that neither model exhibits isotropic characteristics. The value of the vertical coherency function has little correlation with that of the horizontal coherency function. However, the coherence of the vertical ground motion between a pair of stations decreases with their projection distance and the frequency of the ground motion. When the projection distance in the wave direction is greater than 800 meters, the coherency between the two points can be neglected.展开更多
Seismic coherence is used to detect discontinuities in underground media. However, strata with steeply dipping structures often produce false low coherence estimates and thus incorrect discontinuity characterization r...Seismic coherence is used to detect discontinuities in underground media. However, strata with steeply dipping structures often produce false low coherence estimates and thus incorrect discontinuity characterization results. It is important to eliminate or reduce the effect of dipping on coherence estimates. To solve this problem, time-domain dip scanning is typically used to improve estimation of coherence in areas with steeply dipping structures. However, the accuracy of the time-domain estimation of dip is limited by the sampling interval. In contrast, the spectrum amplitude is not affected by the time delays in adjacent seismic traces caused by dipping structures. We propose a coherency algorithm that uses the spectral amplitudes of seismic traces within a predefined analysis window to construct the covariance matrix. The coherency estimates with the proposed algorithm is defined as the ratio between the dominant the constructed covariance matrix. Thus, we eigenvalue and the sum of all eigenvalues of eliminate the effect of dipping structures on coherency estimates. In addition, because different frequency bands of spectral amplitudes are used to estimate coherency, the proposed algorithm has multiscale features. Low frequencies are effective for characterizing large-scale faults, whereas high frequencies are better in characterizing small-scale faults. Application to synthetic and real seismic data show that the proposed algorithm can eliminate the effect of dip and produce better coherence estimates than conventional coherency algorithms in areas with steeply dipping structures.展开更多
The solidification characterization of Mg-xZn-0.5Zr(x=0,1,3,4,5 wt%)alloys has been extensively investigated through thermal analysis,microstructure characterization and thermodynamic calculations.The impact of Zn con...The solidification characterization of Mg-xZn-0.5Zr(x=0,1,3,4,5 wt%)alloys has been extensively investigated through thermal analysis,microstructure characterization and thermodynamic calculations.The impact of Zn content on the grain growth restriction,dendrite coherency and thus the final grain size has been investigated and discussed.Increasing Zn content,the grain size of Mg-xZn-0.5Zr alloy was firstly refined and then coarsened with the finest grain size of^50μm for the Mg-3 Zn-0.5 Zr(ZK31)alloy.Significant effects of the grain size on the mechanical properties were observed in the investigated alloys.The combination of growth restriction factor theory and dendrite coherency point provides a reasonable explanation of the grain size results.It helps to further understand the mechanisms of grain refinement and grain coarsening related to solute content,providing reference for alloy design and grain size prediction.展开更多
At present, the method to study spatial variation of ground motions is statistic analysis based on dense array re-cords such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency f...At present, the method to study spatial variation of ground motions is statistic analysis based on dense array re-cords such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency function model of base rock and different style site. Spatial variation of ground motions in elastic media is analyzed by deterministic method in this paper. Taking elastic half-space model with dislocation source of fault, near-field ground motions are simulated. This model takes strike-slip fault and earth media into account. A coherency func-tion is proposed for base rock site.展开更多
This paper analyzes cache coherency mechanism from the view of system. It firstly discusses caehe-memory hierarchy of Pentium Ⅲ SMP system, including memory area distribution, cache attributes control and bus transac...This paper analyzes cache coherency mechanism from the view of system. It firstly discusses caehe-memory hierarchy of Pentium Ⅲ SMP system, including memory area distribution, cache attributes control and bus transaction. Secondly it analyzes hardware snoopy mechanism of P6 bus and MESI state transitions adopted by Pentium Ⅲ. Based on these, it focuses on how muhiprocessors and the P6 bus cooperate to ensure cache coherency of the whole system, and gives the key of cache coherency design.展开更多
The procerebrum (PC) of the land slug Limax is the olfactory center involved in olfactory discrimination and learning. In the PC, an oscillation of local field potential (LFP) with 0.5 - 1 Hz is observed by electrophy...The procerebrum (PC) of the land slug Limax is the olfactory center involved in olfactory discrimination and learning. In the PC, an oscillation of local field potential (LFP) with 0.5 - 1 Hz is observed by electrophysiological extracellular recording. Additionally, spatiotemporal neural activities in the PC have been examined using optical recordings. However, extracellular recording is preferable to measure neural activities for a long time with a high speed, while it is not abundant in spatial information. In this study, we therefore attempted to elicit spatial information from extracellular recording. For this purpose, we evaluated spatial information included in the LFP compared with the spatiotemporal neural activities measured by the fluorescent voltage imaging. As a result, aversive odors induced the coherent spatiotemporal neural activities in the PC, and the increase in coherency was observed as a change in the LFP waveform. It was also evaluated as a decrease in entropy by analyzing the LFP oscillation patterns and wavelet analysis. Thus, although the LFP provides only one series of signals, the coherency of the spatiotemporal neural activities in the PC can be evaluated by applying extracellular recording with wavelet analysis.展开更多
The waveform data recorded during the site survey of the Naqu seismic array in Aug. 2004 were processed by the author. According to the relativity of site pairs in time and frequency domains, the reference values of t...The waveform data recorded during the site survey of the Naqu seismic array in Aug. 2004 were processed by the author. According to the relativity of site pairs in time and frequency domains, the reference values of the inner ring and outer ring were determined. The author evaluated the array deployed for site survey as the primary array, and the results show that the resolution of the primary array is high enough to locate earthquakes precisely.展开更多
While ptychography is an algorithm based on coherent illumination,satisfactory reconstructions can still be generated in most experiments,even though the radiation sources that are used are not ideally coherent.The un...While ptychography is an algorithm based on coherent illumination,satisfactory reconstructions can still be generated in most experiments,even though the radiation sources that are used are not ideally coherent.The underlying physics of this phenomenon is that the diffraction patterns of partially coherent illumination can be treated as those of purely coherent illumination by altering the intensities of the diffracted beams relative to their real values.On the other hand,due to the inconsistency in the altering interference among all the diffraction beams,noise/distortion is always involved in the reconstructed images.Furthermore,for a weak object,the noise/distortion in the reconstruction can be mostly reduced by using a highly curved beam for illumination in the data recording and forcing the dark field diffraction to be zero in the reconstruction.展开更多
Mixing and coherence are fundamental issues at the heart of understanding fluid dynamics and other non-autonomous dynamical systems. Recently the notion of coherence has come to a more rigorous footing, in particular,...Mixing and coherence are fundamental issues at the heart of understanding fluid dynamics and other non-autonomous dynamical systems. Recently the notion of coherence has come to a more rigorous footing, in particular, within the studies of finite-time nonautonomous dynamical systems. Here we recall “shape coherent sets” which is proven to correspond to slowly evolving curvature, for which tangency of finite time stable foliations (related to a “forward time” perspective) and finite time unstable foliations (related to a “backwards time” perspective) serve a central role. We compare and contrast this perspective to both the variational method of geodesics [17], as well as the coherent pairs perspective [12] from transfer operators.展开更多
The idea of the earthquake (EQ) focus as a coherent electromagnetic (EM) emitter is suggested. This idea elucidates enigmatic properties of the EM voice of the focus: its emission is not continuous, occurring periodic...The idea of the earthquake (EQ) focus as a coherent electromagnetic (EM) emitter is suggested. This idea elucidates enigmatic properties of the EM voice of the focus: its emission is not continuous, occurring periodically in flashes, which are structured as the pulses occurring in bursts;the EM activity increases starting approximately two weeks before the EQ and becomes very weak or completely disappears one day before the EQ (gap of silence). The mechanism of coherency starts with electric discharges of any mini-cracks as a mini-capacitor, which generates EM waves;the latter induces discharges of other cracks, multiplying the amplitude of the wave and creating the pulse of seismic EM signal. It is an avalanche-like mechanism of coherency, which transforms even weak EM signals into intensive EM seismic flashes.展开更多
With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enha...With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enhance the response capability of power systems to extreme events,this study focuses on a method for generator coherency detection.To overcome the shortcomings of the traditional slow coherency method,this paper introduces a novel coherent group identification algorithm based on the theory of nonlinear dynam-ical systems.By analyzing the changing trend of the Euclidean norm of the state variable derivatives in the reduced system,the algorithm can accurately identify the magnitude of the disturbances.Based on the slow coherency methods,the algorithm can correctly recognize coherent generator groups by analyzing system characteristics under varying disturbance magnitudes.This improvement enhances the applicability and accuracy of the coherency detection algorithm under extreme conditions,providing support for emergency control and protection in the power system.Simulations and comparison analyses on IEEE 39-bus system are conducted to validate the accuracy and superiority of the proposed coherent generator group identification method under extreme conditions.展开更多
AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA scree...AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA screening indicators to detect concurrent DR at an early stage.METHODS:A total of 200 patients who treated in the ophthalmology department of the Seventh Affiliated Hospital,Sun Yat-sen University from 2022 to 2023 were included,including 95 first-diagnosed DR patients and 105 patients without DR,and all patients underwent OCTA examination and a collection of demographics and renal function parameters.After a quality check,automated measurements of the foveal avascular zone area,vessel density(VD),and perfusion density(PD)of both 3 mm×3 mm and 6 mm×6 mm windows were obtained.RESULTS:Using random forest and multivariate Logistic regression methods,we developed a diagnostic model for DR based on 12 variables(age,FBG,SBP,DBP,HbA1c,ALT,ALP,urea/Scr,DM duration,HUA,DN,and CMT).Adding specific OCTA parameters enhanced the efficacy of the existing diagnostic model for DR(outer vessel density in 6 mm×6 mm window,AUC=0.837 vs 0.819,P=0.03).In the study of DN patients,the parameters in the 6 mm×6 mm window improved the diagnostic efficacy of DR(inner VD;outer VD;full VD;outer PD;full PD).CONCLUSION:The outer VD in the 6 mm×6 mm window can enhance the efficacy of the traditional DR diagnostic model.Meanwhile,compared with the 3 mm×3 mm window,the microvascular parameters in the 6 mm×6 mm window focusing on DN patients can be more sensitive to diagnosing the occurrence of DR.展开更多
BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic im...BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management strategies.Vascular and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated damage.With the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural changes.AIM To study the macular microvascular and structural changes on OCTA in atypical optic neuritis.METHODS This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy controls.Macular vascular density(MVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using OCTA.RESULTS There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy controls.NMOSD and MOGAD affected eyes had significant GCIPL thinning compared with healthy controls.NMOSD unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected eyes.On comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected eyes.CONCLUSION Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases.展开更多
Geomagnetic observatory data are crucial for all branches of geophysics because they can contribute to earthquake research by detecting anomalies in the Earth’s magnetic field.Recently,data records from the Misallat(...Geomagnetic observatory data are crucial for all branches of geophysics because they can contribute to earthquake research by detecting anomalies in the Earth’s magnetic field.Recently,data records from the Misallat(MLT)and Abu Simbel(ABS)Egyptian geomagnetic observatories were processed and found to be of good quality.In this study,Egyptian observatory data were tested during both quiet and disturbed events and compared with data from INTERMAGNET observatories worldwide at different latitudes and within a narrow range of longitudes in both hemispheres.This study investigated the relationships between magnetic field components from Egyptian observatories and those from INTERMAGNET observatories using graphical representations of the X components;Pearson’s correlation for the X,Y,Z,and F components;cross-correlation for the X component;and wavelet coherence for the F component.The results of this study showed a high correlation between Egyptian observatories and all utilized INTERMAGNET stations,except those located at high latitudes,during both quiet and disturbed events.Additionally,the study confirmed the observed consistency between Egyptian observatories and selected INTERMAGNET stations.Therefore,Egyptian observatories can feasibly fill the gap in the Middle East and North Africa.展开更多
Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing int...Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing internal learning-based video inpainting methods would produce inconsistent structures or blurry textures due to the insufficient utilisation of motion priors within the video sequence.In this paper,the authors propose a new internal learning-based video inpainting model called appearance consistency and motion coherence network(ACMC-Net),which can not only learn the recurrence of appearance prior but can also capture motion coherence prior to improve the quality of the inpainting results.In ACMC-Net,a transformer-based appearance network is developed to capture global context information within the video frame for representing appearance consistency accurately.Additionally,a novel motion coherence learning scheme is proposed to learn the motion prior in a video sequence effectively.Finally,the learnt internal appearance consistency and motion coherence are implicitly propagated to the missing regions to achieve inpainting well.Extensive experiments conducted on the DAVIS dataset show that the proposed model obtains the superior performance in terms of quantitative measurements and produces more visually plausible results compared with the state-of-the-art methods.展开更多
AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This...AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This retrospective study involved 65 RVO patients(65 eyes)who received IVR and were followedup for more than 3mo.ME was categorized into cystoid macular edema(CME),diffuse retinal thickening(DRT),and serous retinal detachment(SRD)according to optical coherence tomography(OCT)images.The comparison of best corrected visual acuity(BCVA;logMAR)and central macular thickness(CMT)among different follow-up points and those among 3 groups were performed by Kruskal-Wallis test.The correlation between BCVA and baseline parameters during treatment was analyzed using Spearman correlation analysis.RESULTS:BCVA tended to improve in all groups,with marked improvement in CME and DRT groups.CMT showed the greatest reduction after 1wk,and remained stable over the following 3mo.DRT patients had the worst BCVA and the highest CMT at baseline,but the differences became smaller after IVR treatment.CMT in SRD group was significantly better than in CME and DRT groups 3mo after IVR.Most patients of CME and SRD groups transitioned to a normal pattern at 3mo follow-up.DRT patients were most likely to transform into the other morphological groups,while SRD patients showed minimal transitions.BCVA at baseline was identified as the most important prognostic indicator in all 3 groups.Additionally,DRT patients with a longer clinical course,higher CMT and central retinal vein occlusion(CRVO)tend to exhibit worse BCVA after treatment.In addition,CRVO patients are more likely to have worse BCVA at 2 and 3mo follow-up compared with branch retinal vein occlusion(BRVO)patients in CME group.SRD patients with higher baseline CMT were prone to experiencing worse BCVA after treatment.CONCLUSION:The effectiveness of IVR is strongly correlated with baseline BCVA in all 3 groups.Baseline parameters including clinical course,CMT,and RVO position are also useful in predicting the BCVA at different time points after treatment.展开更多
Densely distributed coherent nanoparticles(DCN)in steel matrix can enhance the work-hardening ability and ductility of steel simultaneously.All the routes to this end can be generally classified into the liquid-solid ...Densely distributed coherent nanoparticles(DCN)in steel matrix can enhance the work-hardening ability and ductility of steel simultaneously.All the routes to this end can be generally classified into the liquid-solid route and the solid-solid route.However,the formation of DCN structures in steel requires long processes and complex steps.So far,obtaining steel with coherent particle enhancement in a short time remains a bottleneck,and some necessary steps remain unavoidable.Here,we show a high-efficiency liquid-phase refining process reinforced by a dynamic magnetic field.Ti-Y-Mn-O particles had an average size of around(3.53±1.21)nm and can be obtained in just around 180 s.These small nanoparticles were coherent with the matrix,implying no accumulated dislocations between the particles and the steel matrix.Our findings have a potential application for improving material machining capacity,creep resistance,and radiation resistance.展开更多
To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these me...To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly age-related.In this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed laser.We observed the molding process in mice of different ages and presented age-dependent vascular embolism differentiation.Moreover,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a stroke.Our imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.展开更多
文摘The coarsening behavior of Cr precipitates in Cu-0.1Ag-0.5Cr alloy was investigated, and the effects of aging processes on the microstructure and properties were discussed. The results show that the radius for coherent/semi-coherent transition of the Cr precipitates is determined from TEM micrographs as 1545nm. The calculated value of critical radius for a particle begining to lose coherency is about 12.5nm. The coherent (r<15nm) precipitates are found to coarsen and become semi-coherent during the passage of low-angle boundaries during recovery. The passage of high-angle boundaries through semi-coherent precipitates during recrystallization occurs by migration of the particle, resulting in the precipitates maintaining semi-coherent with the new grain.
基金Research Fund for Communications in Western China Under Grant No. 200431800028
文摘Proper Orthogonal Decomposition （POD） provides a powerful modal transformation tool for stochastic dynamics. In this paper, coherency matrix-based proper orthogonal decomposition （CPOD） is presented as an innovative form of the POD based on cross power spectral density matrices. By introducing a discretizing scheme, the CPOD-based spectral representation method is obtained for use in stochastic simulation. Moreover, some criteria are proposed that allow the truncation order of CPOD to be conveniently determined. A numerical example to illustrate the application of the proposed method for the simulation of a wind velocity field is provided.
基金Supported by National Natural Science Foundation of China Under Grant No.90715005,No.NCET-07-0186 and No.200802860007
文摘Many studies have focused on horizontal ground motion, resulting in many coherency functions for horizontal ground motion while neglecting related problems arising from vertical ground motion. However, seismic events have demonstrated that the vertical components of ground motion sometimes govern the ultimate failure of structures. In this paper, a vertical coherency function model of spatial ground motion is proposed based on the Hao model and SMART 1 array records, and the validity of the model is demonstrated. The vertical coherency function model of spatial ground motion is also compared with the horizontal coherency function model, indicating that neither model exhibits isotropic characteristics. The value of the vertical coherency function has little correlation with that of the horizontal coherency function. However, the coherence of the vertical ground motion between a pair of stations decreases with their projection distance and the frequency of the ground motion. When the projection distance in the wave direction is greater than 800 meters, the coherency between the two points can be neglected.
基金sponsored by National Key S&T Project of China(No.2011ZX05004-003)the Research Program of RIPED(No.101002kt0b52135)
文摘Seismic coherence is used to detect discontinuities in underground media. However, strata with steeply dipping structures often produce false low coherence estimates and thus incorrect discontinuity characterization results. It is important to eliminate or reduce the effect of dipping on coherence estimates. To solve this problem, time-domain dip scanning is typically used to improve estimation of coherence in areas with steeply dipping structures. However, the accuracy of the time-domain estimation of dip is limited by the sampling interval. In contrast, the spectrum amplitude is not affected by the time delays in adjacent seismic traces caused by dipping structures. We propose a coherency algorithm that uses the spectral amplitudes of seismic traces within a predefined analysis window to construct the covariance matrix. The coherency estimates with the proposed algorithm is defined as the ratio between the dominant the constructed covariance matrix. Thus, we eigenvalue and the sum of all eigenvalues of eliminate the effect of dipping structures on coherency estimates. In addition, because different frequency bands of spectral amplitudes are used to estimate coherency, the proposed algorithm has multiscale features. Low frequencies are effective for characterizing large-scale faults, whereas high frequencies are better in characterizing small-scale faults. Application to synthetic and real seismic data show that the proposed algorithm can eliminate the effect of dip and produce better coherence estimates than conventional coherency algorithms in areas with steeply dipping structures.
基金supports by the National Key Research and Development Program of China(No.2017YFB0702001)the Natrual Science Foundation of China(No.51621063)+2 种基金the support from the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies,the Collaborative Innovation Center of High-End Manufacturing Equipment and the Science and Technology Department of Shaanxi Province(Nos.2016KTZDGY-04-03 and 2016KTZDGY-04-04)the National Natural Science Foundation for Young Scholars(No.51701218)the National Science and Technology Major Project of China through Project No.2017ZX04014001。
文摘The solidification characterization of Mg-xZn-0.5Zr(x=0,1,3,4,5 wt%)alloys has been extensively investigated through thermal analysis,microstructure characterization and thermodynamic calculations.The impact of Zn content on the grain growth restriction,dendrite coherency and thus the final grain size has been investigated and discussed.Increasing Zn content,the grain size of Mg-xZn-0.5Zr alloy was firstly refined and then coarsened with the finest grain size of^50μm for the Mg-3 Zn-0.5 Zr(ZK31)alloy.Significant effects of the grain size on the mechanical properties were observed in the investigated alloys.The combination of growth restriction factor theory and dendrite coherency point provides a reasonable explanation of the grain size results.It helps to further understand the mechanisms of grain refinement and grain coarsening related to solute content,providing reference for alloy design and grain size prediction.
基金National Natural Science Foundation of China (59895410)
文摘At present, the method to study spatial variation of ground motions is statistic analysis based on dense array re-cords such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency function model of base rock and different style site. Spatial variation of ground motions in elastic media is analyzed by deterministic method in this paper. Taking elastic half-space model with dislocation source of fault, near-field ground motions are simulated. This model takes strike-slip fault and earth media into account. A coherency func-tion is proposed for base rock site.
文摘This paper analyzes cache coherency mechanism from the view of system. It firstly discusses caehe-memory hierarchy of Pentium Ⅲ SMP system, including memory area distribution, cache attributes control and bus transaction. Secondly it analyzes hardware snoopy mechanism of P6 bus and MESI state transitions adopted by Pentium Ⅲ. Based on these, it focuses on how muhiprocessors and the P6 bus cooperate to ensure cache coherency of the whole system, and gives the key of cache coherency design.
文摘The procerebrum (PC) of the land slug Limax is the olfactory center involved in olfactory discrimination and learning. In the PC, an oscillation of local field potential (LFP) with 0.5 - 1 Hz is observed by electrophysiological extracellular recording. Additionally, spatiotemporal neural activities in the PC have been examined using optical recordings. However, extracellular recording is preferable to measure neural activities for a long time with a high speed, while it is not abundant in spatial information. In this study, we therefore attempted to elicit spatial information from extracellular recording. For this purpose, we evaluated spatial information included in the LFP compared with the spatiotemporal neural activities measured by the fluorescent voltage imaging. As a result, aversive odors induced the coherent spatiotemporal neural activities in the PC, and the increase in coherency was observed as a change in the LFP waveform. It was also evaluated as a decrease in entropy by analyzing the LFP oscillation patterns and wavelet analysis. Thus, although the LFP provides only one series of signals, the coherency of the spatiotemporal neural activities in the PC can be evaluated by applying extracellular recording with wavelet analysis.
基金The research was under the construction of the Naquseismic array of Chinese Digital Seismography Observation Networkin National 10th Five-Year Program.
文摘The waveform data recorded during the site survey of the Naqu seismic array in Aug. 2004 were processed by the author. According to the relativity of site pairs in time and frequency domains, the reference values of the inner ring and outer ring were determined. The author evaluated the array deployed for site survey as the primary array, and the results show that the resolution of the primary array is high enough to locate earthquakes precisely.
基金supported by the Funds from the Engineering and Physical Sciences Research Council(Grant No.EP/E034055/1)the One Hundred Talent Project of the Chinese Academy of Sciences and the Financial Support(Grant No.GFZX0205010502.12)
文摘While ptychography is an algorithm based on coherent illumination,satisfactory reconstructions can still be generated in most experiments,even though the radiation sources that are used are not ideally coherent.The underlying physics of this phenomenon is that the diffraction patterns of partially coherent illumination can be treated as those of purely coherent illumination by altering the intensities of the diffracted beams relative to their real values.On the other hand,due to the inconsistency in the altering interference among all the diffraction beams,noise/distortion is always involved in the reconstructed images.Furthermore,for a weak object,the noise/distortion in the reconstruction can be mostly reduced by using a highly curved beam for illumination in the data recording and forcing the dark field diffraction to be zero in the reconstruction.
文摘Mixing and coherence are fundamental issues at the heart of understanding fluid dynamics and other non-autonomous dynamical systems. Recently the notion of coherence has come to a more rigorous footing, in particular, within the studies of finite-time nonautonomous dynamical systems. Here we recall “shape coherent sets” which is proven to correspond to slowly evolving curvature, for which tangency of finite time stable foliations (related to a “forward time” perspective) and finite time unstable foliations (related to a “backwards time” perspective) serve a central role. We compare and contrast this perspective to both the variational method of geodesics [17], as well as the coherent pairs perspective [12] from transfer operators.
文摘The idea of the earthquake (EQ) focus as a coherent electromagnetic (EM) emitter is suggested. This idea elucidates enigmatic properties of the EM voice of the focus: its emission is not continuous, occurring periodically in flashes, which are structured as the pulses occurring in bursts;the EM activity increases starting approximately two weeks before the EQ and becomes very weak or completely disappears one day before the EQ (gap of silence). The mechanism of coherency starts with electric discharges of any mini-cracks as a mini-capacitor, which generates EM waves;the latter induces discharges of other cracks, multiplying the amplitude of the wave and creating the pulse of seismic EM signal. It is an avalanche-like mechanism of coherency, which transforms even weak EM signals into intensive EM seismic flashes.
基金supported by National Natural Science Foundation of China(Grant No:52477133)Science and Technology Project of China Southern Power Grid(Grant No.GDKJXM20231178(036100KC23110012)+1 种基金GDKJXM20240389(030000KC24040053))Sanya Yazhou Bay Science and Technology City(Grant No:SKJC-JYRC-2024-66).
文摘With the rapid development of large-scale regional interconnected power grids,the risk of cascading failures under extreme condi-tions,such as natural disasters and military strikes,has increased significantly.To enhance the response capability of power systems to extreme events,this study focuses on a method for generator coherency detection.To overcome the shortcomings of the traditional slow coherency method,this paper introduces a novel coherent group identification algorithm based on the theory of nonlinear dynam-ical systems.By analyzing the changing trend of the Euclidean norm of the state variable derivatives in the reduced system,the algorithm can accurately identify the magnitude of the disturbances.Based on the slow coherency methods,the algorithm can correctly recognize coherent generator groups by analyzing system characteristics under varying disturbance magnitudes.This improvement enhances the applicability and accuracy of the coherency detection algorithm under extreme conditions,providing support for emergency control and protection in the power system.Simulations and comparison analyses on IEEE 39-bus system are conducted to validate the accuracy and superiority of the proposed coherent generator group identification method under extreme conditions.
文摘AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA screening indicators to detect concurrent DR at an early stage.METHODS:A total of 200 patients who treated in the ophthalmology department of the Seventh Affiliated Hospital,Sun Yat-sen University from 2022 to 2023 were included,including 95 first-diagnosed DR patients and 105 patients without DR,and all patients underwent OCTA examination and a collection of demographics and renal function parameters.After a quality check,automated measurements of the foveal avascular zone area,vessel density(VD),and perfusion density(PD)of both 3 mm×3 mm and 6 mm×6 mm windows were obtained.RESULTS:Using random forest and multivariate Logistic regression methods,we developed a diagnostic model for DR based on 12 variables(age,FBG,SBP,DBP,HbA1c,ALT,ALP,urea/Scr,DM duration,HUA,DN,and CMT).Adding specific OCTA parameters enhanced the efficacy of the existing diagnostic model for DR(outer vessel density in 6 mm×6 mm window,AUC=0.837 vs 0.819,P=0.03).In the study of DN patients,the parameters in the 6 mm×6 mm window improved the diagnostic efficacy of DR(inner VD;outer VD;full VD;outer PD;full PD).CONCLUSION:The outer VD in the 6 mm×6 mm window can enhance the efficacy of the traditional DR diagnostic model.Meanwhile,compared with the 3 mm×3 mm window,the microvascular parameters in the 6 mm×6 mm window focusing on DN patients can be more sensitive to diagnosing the occurrence of DR.
文摘BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management strategies.Vascular and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated damage.With the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural changes.AIM To study the macular microvascular and structural changes on OCTA in atypical optic neuritis.METHODS This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy controls.Macular vascular density(MVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using OCTA.RESULTS There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy controls.NMOSD and MOGAD affected eyes had significant GCIPL thinning compared with healthy controls.NMOSD unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected eyes.On comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected eyes.CONCLUSION Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases.
文摘Geomagnetic observatory data are crucial for all branches of geophysics because they can contribute to earthquake research by detecting anomalies in the Earth’s magnetic field.Recently,data records from the Misallat(MLT)and Abu Simbel(ABS)Egyptian geomagnetic observatories were processed and found to be of good quality.In this study,Egyptian observatory data were tested during both quiet and disturbed events and compared with data from INTERMAGNET observatories worldwide at different latitudes and within a narrow range of longitudes in both hemispheres.This study investigated the relationships between magnetic field components from Egyptian observatories and those from INTERMAGNET observatories using graphical representations of the X components;Pearson’s correlation for the X,Y,Z,and F components;cross-correlation for the X component;and wavelet coherence for the F component.The results of this study showed a high correlation between Egyptian observatories and all utilized INTERMAGNET stations,except those located at high latitudes,during both quiet and disturbed events.Additionally,the study confirmed the observed consistency between Egyptian observatories and selected INTERMAGNET stations.Therefore,Egyptian observatories can feasibly fill the gap in the Middle East and North Africa.
基金Shenzhen Science and Technology Programme,Grant/Award Number:JCYJ202308071208000012023 Shenzhen sustainable supporting funds for colleges and universities,Grant/Award Number:20231121165240001Guangdong Provincial Key Laboratory of Ultra High Definition Immersive Media Technology,Grant/Award Number:2024B1212010006。
文摘Internal learning-based video inpainting methods have shown promising results by exploiting the intrinsic properties of the video to fill in the missing region without external dataset supervision.However,existing internal learning-based video inpainting methods would produce inconsistent structures or blurry textures due to the insufficient utilisation of motion priors within the video sequence.In this paper,the authors propose a new internal learning-based video inpainting model called appearance consistency and motion coherence network(ACMC-Net),which can not only learn the recurrence of appearance prior but can also capture motion coherence prior to improve the quality of the inpainting results.In ACMC-Net,a transformer-based appearance network is developed to capture global context information within the video frame for representing appearance consistency accurately.Additionally,a novel motion coherence learning scheme is proposed to learn the motion prior in a video sequence effectively.Finally,the learnt internal appearance consistency and motion coherence are implicitly propagated to the missing regions to achieve inpainting well.Extensive experiments conducted on the DAVIS dataset show that the proposed model obtains the superior performance in terms of quantitative measurements and produces more visually plausible results compared with the state-of-the-art methods.
基金Supported by the Suzhou Medical Innovation Application Research Project(SZM2023027).
文摘AIM:To explore the morphological and functional parameters to evaluate the effectiveness of intravitreal injections of ranibizumab(IVR)in treating macular edema(ME)secondary to retinal vein occlusion(RVO).METHODS:This retrospective study involved 65 RVO patients(65 eyes)who received IVR and were followedup for more than 3mo.ME was categorized into cystoid macular edema(CME),diffuse retinal thickening(DRT),and serous retinal detachment(SRD)according to optical coherence tomography(OCT)images.The comparison of best corrected visual acuity(BCVA;logMAR)and central macular thickness(CMT)among different follow-up points and those among 3 groups were performed by Kruskal-Wallis test.The correlation between BCVA and baseline parameters during treatment was analyzed using Spearman correlation analysis.RESULTS:BCVA tended to improve in all groups,with marked improvement in CME and DRT groups.CMT showed the greatest reduction after 1wk,and remained stable over the following 3mo.DRT patients had the worst BCVA and the highest CMT at baseline,but the differences became smaller after IVR treatment.CMT in SRD group was significantly better than in CME and DRT groups 3mo after IVR.Most patients of CME and SRD groups transitioned to a normal pattern at 3mo follow-up.DRT patients were most likely to transform into the other morphological groups,while SRD patients showed minimal transitions.BCVA at baseline was identified as the most important prognostic indicator in all 3 groups.Additionally,DRT patients with a longer clinical course,higher CMT and central retinal vein occlusion(CRVO)tend to exhibit worse BCVA after treatment.In addition,CRVO patients are more likely to have worse BCVA at 2 and 3mo follow-up compared with branch retinal vein occlusion(BRVO)patients in CME group.SRD patients with higher baseline CMT were prone to experiencing worse BCVA after treatment.CONCLUSION:The effectiveness of IVR is strongly correlated with baseline BCVA in all 3 groups.Baseline parameters including clinical course,CMT,and RVO position are also useful in predicting the BCVA at different time points after treatment.
基金financially supported by the National Natural Science Foundation of China(No.51771125)the Sichuan Province Science and Technology Support Program(No.2020YFG0102)。
文摘Densely distributed coherent nanoparticles(DCN)in steel matrix can enhance the work-hardening ability and ductility of steel simultaneously.All the routes to this end can be generally classified into the liquid-solid route and the solid-solid route.However,the formation of DCN structures in steel requires long processes and complex steps.So far,obtaining steel with coherent particle enhancement in a short time remains a bottleneck,and some necessary steps remain unavoidable.Here,we show a high-efficiency liquid-phase refining process reinforced by a dynamic magnetic field.Ti-Y-Mn-O particles had an average size of around(3.53±1.21)nm and can be obtained in just around 180 s.These small nanoparticles were coherent with the matrix,implying no accumulated dislocations between the particles and the steel matrix.Our findings have a potential application for improving material machining capacity,creep resistance,and radiation resistance.
基金supported by University of Macao,China,Nos.MYRG2022-00054-FHS and MYRG-GRG2023-00038-FHS-UMDF(to ZY)the Macao Science and Technology Development Fund,China,Nos.FDCT0048/2021/AGJ and FDCT0020/2019/AMJ and FDCT 0011/2018/A1(to ZY)Natural Science Foundation of Guangdong Province of China,No.EF017/FHS-YZ/2021/GDSTC(to ZY)。
文摘To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly age-related.In this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed laser.We observed the molding process in mice of different ages and presented age-dependent vascular embolism differentiation.Moreover,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a stroke.Our imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.
