The generalized two-dimensional correlation analysis based on time-resolved light scattering patterns （2D TRLS） has been employed to study the phase separation process of an epoxy-amine-polyethersulfone blend in whi...The generalized two-dimensional correlation analysis based on time-resolved light scattering patterns （2D TRLS） has been employed to study the phase separation process of an epoxy-amine-polyethersulfone blend in which the secondary phase separation takes place. The results of the 2D TRLS provided more detailed information that was not readily observed in the 1D TRLS patterns. （i） During the first process of phase separation, the sequential order of coarsening in size of the domains among the larger and smaller ones has been reversed between the diffusion regime and the hydrodynamic regime. （ii） The change of the larger domains in size, due to the hydrodynamic flow in the late stage of the first phase separation process, keeps on taking place earlier than that of the new domains appeared in the secondary phase separation process. （iii） During the secondary phase separation process the size growth of the smaller domains takes place earlier than that of the larger ones, probably due to the assumption that the coarsening mode could decrease the interface tension more quickly.展开更多
We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Hel...We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Helmholtz equations. We prove the classical reciprocity principle, a general scattering theorem and an optical theorem in R<sup>2</sup>. Using Herglotz wave functions we define the corresponding far field operator. Applying the general scattering theorem useful relations are proved for the reconstruction of the scatterer. We also prove that for real chirality measure of the penetrable scatterer the far field operator has a countable number of eigenvalues which lie on a circle.展开更多
The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der...The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der Waals compound VI3,revealed a structural transition above the magnetic transition but output controversial analysis on symmetry.In this paper we carried out polarized Raman scattering measurements on VI3 from 10 K to 300 K,with focus on the two Ag phonon modes at^71.1 cm^-1 and 128.4 cm-1.Our careful symmetry analysis based on the angle-dependent spectra demonstrates that the crystal symmetry can be well described by C2h rather than D3d both above and below structural phase transition.We further performed temperature-dependent Raman experiments to study the magnetism in VI3.Fano asymmetry and anomalous linewidth drop of two Ag phonon modes at low temperatures,point to a significant spin-phonon coupling.This is also supported by the softening of 71.1-cm^-1 mode above the magnetic transition.The study provides the fundamental information on lattice dynamics and clarifies the symmetry in VI3.And spin-phonon coupling existing in a wide temperature range revealed here may be meaningful in applications.展开更多
Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-...Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezomagnetic ＂comparison body＂ is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green＇s function, which is obtained using the Radon transform. The expression is further simplified under conditions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelectric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.展开更多
Lorenz-RR scatter plot has an obvious shortcoming in that it does not indicate the time when the scatter point happens.On the Lorenz RR scatter plot,one cannot know the time during which the cardiac rhythms take place...Lorenz-RR scatter plot has an obvious shortcoming in that it does not indicate the time when the scatter point happens.On the Lorenz RR scatter plot,one cannot know the time during which the cardiac rhythms take place.Since occurrence of cardiac rhythms is time-related,time should be introduced to such plots.In this study,time was used as abscissa and RR interval(the time interval between the previous RR wave and the R wave)as the ordinate and time was compressed into a visually observable length,and thereby a timed RR-interval scatter plot,or t-RR scatter plot,for short,was developed.On t-RR scatter plot,the patterns were band-shaped or were of linear type.On the t-RR plot,the sinus rhythm presented bands of various widths,with the spiculate or burred upper and lower boundaries,having diurnal variation.Premature beats showed separate layers(“stratification”),the layer number corresponding the number of RR-intervals.With simple premature beats,the layers were clearly separated.With parasystole rhythm,the upper and lower bands or layers might become thicker.With arial premature beats,the space or distance between layers varied.Ventricular premature beats presented equal space or distance between layers.With tachycardia,the lower layer became a“solid”layer.With atrial fibration,the“stratification”disappeared,presenting thicker or widened layers or bands,with neat lower boundary.With atrial flutter,the layers went parallel,with the layers being evenly separated or some distances being exact multiples of others.The second degree atrioventricular block displayed two layers,the lower and upper bands being equally away from the X-axis,presenting a straight line(pacing at a fixed rate)or a thicker or wider bands,with a neat upper boundary(the lowest pacing rate).When the scatter plot presented uncharacteristic patterns or had some scattered points,which rendered diagnosis difficult,a reverse technology could be used.Briefly,upon selection of scattered points,they were subjected to computerization,by regression,to reveal the piece of electrocardiogram(ECG)containing an R wave(QRS complex).Then ECG was analyzed to diagnose the cardiac rhythms.In conclusion,t-RR is a novel methodology which helps us understand heart rhythms from a new perspective.展开更多
On the conditions of low-resolution radar, a parametric model for two-dimensional radar target is described here according to the theory of electromagnetic scattering and the geometrical theory of diffraction. A high ...On the conditions of low-resolution radar, a parametric model for two-dimensional radar target is described here according to the theory of electromagnetic scattering and the geometrical theory of diffraction. A high resolution estimation algorithm to extract the model parameters is also developed by building the relation of the scattering model and Prony model. The analysis of Cramer-Rao bound and simulation show that the method here has better statistical performance. The simulated analysis also indicates that the accurate extraction of the diffraction coefficient of scattering center is restricted by signal to noise ratio, radar center frequency and radar bandwidth.展开更多
The electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases with different surface morphology has been investigated.Large electron mobility anisotropy is found for the sample with anisotropic mor...The electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases with different surface morphology has been investigated.Large electron mobility anisotropy is found for the sample with anisotropic morphology,which is mainly induced by the threading dislocations in the InAs layer.For the samples with isotropic morphology,the electron mobility is also anisotropic and could be attributed to the piezoelectric scattering.At low temperature (below transition temperature),the piezoelectric scattering is enhanced with the increase of temperature,leading to the increase of electron mobility anisotropy.At high temperature (above transition temperature),the phonon scattering becomes dominant.Because the phonon scattering is isotropic,the electron mobility anisotropy in all the samples would be reduced.Our results provide useful information for the comprehensive understanding of electron mobility anisotropy in the (Al,Ga)Sb/InAs system.展开更多
A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioven...A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioventricular node double path caused by interpolated ventricular premature contraction imprints a specifi c pattern on three-dimensional Lorenz plots generated from 24-hour Holter recordings.We found two independent subclusters separated from the interpolated premature beat precluster,the interpolated premature beat cluster,and the interpolated premature beat postcluster,respectively.Combined with use of the trajectory tracking function and the leap phenomenon,our results reveal the presence of the atrioventricular node double conduction path.展开更多
基金supported by the National Natural Science of Foundation of China(NSFC)(Nos.20674014, 20425415,20274010,50103003,20221402)
文摘The generalized two-dimensional correlation analysis based on time-resolved light scattering patterns （2D TRLS） has been employed to study the phase separation process of an epoxy-amine-polyethersulfone blend in which the secondary phase separation takes place. The results of the 2D TRLS provided more detailed information that was not readily observed in the 1D TRLS patterns. （i） During the first process of phase separation, the sequential order of coarsening in size of the domains among the larger and smaller ones has been reversed between the diffusion regime and the hydrodynamic regime. （ii） The change of the larger domains in size, due to the hydrodynamic flow in the late stage of the first phase separation process, keeps on taking place earlier than that of the new domains appeared in the secondary phase separation process. （iii） During the secondary phase separation process the size growth of the smaller domains takes place earlier than that of the larger ones, probably due to the assumption that the coarsening mode could decrease the interface tension more quickly.
文摘We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Helmholtz equations. We prove the classical reciprocity principle, a general scattering theorem and an optical theorem in R<sup>2</sup>. Using Herglotz wave functions we define the corresponding far field operator. Applying the general scattering theorem useful relations are proved for the reconstruction of the scatterer. We also prove that for real chirality measure of the penetrable scatterer the far field operator has a countable number of eigenvalues which lie on a circle.
基金Project supported by the Science Fund from the Ministry of Science and Technology of China(Grant Nos.2017YFA0302904 and 2016YFA0300504)the National Natural Science Foundation of China(Grant Nos.11774419,U1932215,11774423,and 11822412)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Renmin University of China(RUC)(Grant Nos.15XNLQ07,18XNLG14,and 19XNLG17).
文摘The layered magnetic van der Waals materials have generated tremendous interest due to their potential applications and importance in fundamental research.Previous x-ray diffraction(XRD)studies on the magnetic van der Waals compound VI3,revealed a structural transition above the magnetic transition but output controversial analysis on symmetry.In this paper we carried out polarized Raman scattering measurements on VI3 from 10 K to 300 K,with focus on the two Ag phonon modes at^71.1 cm^-1 and 128.4 cm-1.Our careful symmetry analysis based on the angle-dependent spectra demonstrates that the crystal symmetry can be well described by C2h rather than D3d both above and below structural phase transition.We further performed temperature-dependent Raman experiments to study the magnetism in VI3.Fano asymmetry and anomalous linewidth drop of two Ag phonon modes at low temperatures,point to a significant spin-phonon coupling.This is also supported by the softening of 71.1-cm^-1 mode above the magnetic transition.The study provides the fundamental information on lattice dynamics and clarifies the symmetry in VI3.And spin-phonon coupling existing in a wide temperature range revealed here may be meaningful in applications.
基金supported by the National Natural Science Foundation of China (Nos. 10732100, 10572155)the Science and Technology Planning Project of Guangdong Province of China (No. 2006A11001002)the Ph. D. Programs Foundation of Ministry of Education of China (No. 2006300004111179)
文摘Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezomagnetic ＂comparison body＂ is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green＇s function, which is obtained using the Radon transform. The expression is further simplified under conditions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelectric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.
文摘Lorenz-RR scatter plot has an obvious shortcoming in that it does not indicate the time when the scatter point happens.On the Lorenz RR scatter plot,one cannot know the time during which the cardiac rhythms take place.Since occurrence of cardiac rhythms is time-related,time should be introduced to such plots.In this study,time was used as abscissa and RR interval(the time interval between the previous RR wave and the R wave)as the ordinate and time was compressed into a visually observable length,and thereby a timed RR-interval scatter plot,or t-RR scatter plot,for short,was developed.On t-RR scatter plot,the patterns were band-shaped or were of linear type.On the t-RR plot,the sinus rhythm presented bands of various widths,with the spiculate or burred upper and lower boundaries,having diurnal variation.Premature beats showed separate layers(“stratification”),the layer number corresponding the number of RR-intervals.With simple premature beats,the layers were clearly separated.With parasystole rhythm,the upper and lower bands or layers might become thicker.With arial premature beats,the space or distance between layers varied.Ventricular premature beats presented equal space or distance between layers.With tachycardia,the lower layer became a“solid”layer.With atrial fibration,the“stratification”disappeared,presenting thicker or widened layers or bands,with neat lower boundary.With atrial flutter,the layers went parallel,with the layers being evenly separated or some distances being exact multiples of others.The second degree atrioventricular block displayed two layers,the lower and upper bands being equally away from the X-axis,presenting a straight line(pacing at a fixed rate)or a thicker or wider bands,with a neat upper boundary(the lowest pacing rate).When the scatter plot presented uncharacteristic patterns or had some scattered points,which rendered diagnosis difficult,a reverse technology could be used.Briefly,upon selection of scattered points,they were subjected to computerization,by regression,to reveal the piece of electrocardiogram(ECG)containing an R wave(QRS complex).Then ECG was analyzed to diagnose the cardiac rhythms.In conclusion,t-RR is a novel methodology which helps us understand heart rhythms from a new perspective.
文摘On the conditions of low-resolution radar, a parametric model for two-dimensional radar target is described here according to the theory of electromagnetic scattering and the geometrical theory of diffraction. A high resolution estimation algorithm to extract the model parameters is also developed by building the relation of the scattering model and Prony model. The analysis of Cramer-Rao bound and simulation show that the method here has better statistical performance. The simulated analysis also indicates that the accurate extraction of the diffraction coefficient of scattering center is restricted by signal to noise ratio, radar center frequency and radar bandwidth.
基金supported by NSFC (Grants No. 11834013 and 12174383)support from the Youth Innovation Promotion Association, Chinese Academy of Sciences (No. 2021110)。
文摘The electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases with different surface morphology has been investigated.Large electron mobility anisotropy is found for the sample with anisotropic morphology,which is mainly induced by the threading dislocations in the InAs layer.For the samples with isotropic morphology,the electron mobility is also anisotropic and could be attributed to the piezoelectric scattering.At low temperature (below transition temperature),the piezoelectric scattering is enhanced with the increase of temperature,leading to the increase of electron mobility anisotropy.At high temperature (above transition temperature),the phonon scattering becomes dominant.Because the phonon scattering is isotropic,the electron mobility anisotropy in all the samples would be reduced.Our results provide useful information for the comprehensive understanding of electron mobility anisotropy in the (Al,Ga)Sb/InAs system.
文摘A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioventricular node double path caused by interpolated ventricular premature contraction imprints a specifi c pattern on three-dimensional Lorenz plots generated from 24-hour Holter recordings.We found two independent subclusters separated from the interpolated premature beat precluster,the interpolated premature beat cluster,and the interpolated premature beat postcluster,respectively.Combined with use of the trajectory tracking function and the leap phenomenon,our results reveal the presence of the atrioventricular node double conduction path.
