The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explor...The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explored crust and upper mantle structures by joint inversion of the Rayleigh wave ZH ratio and surface wave dispersion.However,all these studies have used a 1-D depth sensitivity kernel,and this kernel may lack precision when the structure varies a great deal laterally.Here,we present a systematic investigation of the two-dimensional(2-D)Rayleigh wave ZH ratio kernel based on the adjoint-wavefield method and perform two synthetic tests using the new kernel.The 2-D ZH ratio kernel is consistent with the traditional 1-D sensitivity kernel but has an asymmetric pattern with a preferred orientation toward the source.The predominant effect caused by heterogeneity can clearly be seen from kernels calculated from models with 2-D heterogeneities,which confirms the necessity of using the new 2-D kernel in some complex regions.Inversion tests using synthetic data show that the 2-D ZH ratio kernel has the potential to resolve small anomalies as well as complex lateral structures.展开更多
Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of...Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.展开更多
Posidonia oceanicameadows are experiencing a progressive decline, and monitoring their status is crucial for the maintenance of theseecosystems. We performed a comparativeanalysis of bed density, total phenol content ...Posidonia oceanicameadows are experiencing a progressive decline, and monitoring their status is crucial for the maintenance of theseecosystems. We performed a comparativeanalysis of bed density, total phenol content and protein expression pattern to assess the conservation status ofPosidoniaplants from the S. Marinella (Rome, Italy) meadow. The total phenol content was inversely related to maximum beddensity, confirming the relationship betweenhigh phenol content and stressful conditions. In addition, protein expression pattern profilesshowed that the number of differentially expressed proteins was dramatically reduced in the latest years compared to previous analyses. Our results support the usefulness of integrating solid descriptors, such as phenol content, with novel biochemical/molecular approaches in the monitoring of meadows.展开更多
Traffic flows form a complex system, especially in the context of urban sprawl. Direct estimation of traffic flows requires significant efforts and knowing in advance where to focus the study and where to place tools ...Traffic flows form a complex system, especially in the context of urban sprawl. Direct estimation of traffic flows requires significant efforts and knowing in advance where to focus the study and where to place tools to directly measure traffic flows, and consequently traffic congestion could lead to significant savings in time and money. In the case of Rome municipality, we have monitored a situation in which a very high rate of urban fragmentation has occurred in the last 30 years, making the direct estimation of traffic difficult. The work described here can help to solve the problem of estimating traffic flows and in particular the congestion phenomenon through a very cheap approach by using remote sensing and geographical information system technology. This method is based on the identification of attractor points that draw traffic flows such as malls, schools, offices, shops, etc. that is to say, points in a territory that attract a certain number of people with vehicles (estimated with a scale) in specific periods of the day. The identification of those points and the calculation of the urban density through the satellite image processing have allowed the creation of a congestion map for the study area. Then the road network and the buildings have been classified according to the congestion values. The results highlight the most critical and congested areas that affect the traffic flows and impact the quality of life.展开更多
基金This study was funded by the National Key R&D Program of China(2016YFC0600301,2018YFC1503400)the National Natural Science Foundation of China(41790464)+1 种基金Natural Science Foundation of Jiangsu Province of China(BK20190499)the Fundamental Research Funds for the Central Universities(2019B0071428).
文摘The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explored crust and upper mantle structures by joint inversion of the Rayleigh wave ZH ratio and surface wave dispersion.However,all these studies have used a 1-D depth sensitivity kernel,and this kernel may lack precision when the structure varies a great deal laterally.Here,we present a systematic investigation of the two-dimensional(2-D)Rayleigh wave ZH ratio kernel based on the adjoint-wavefield method and perform two synthetic tests using the new kernel.The 2-D ZH ratio kernel is consistent with the traditional 1-D sensitivity kernel but has an asymmetric pattern with a preferred orientation toward the source.The predominant effect caused by heterogeneity can clearly be seen from kernels calculated from models with 2-D heterogeneities,which confirms the necessity of using the new 2-D kernel in some complex regions.Inversion tests using synthetic data show that the 2-D ZH ratio kernel has the potential to resolve small anomalies as well as complex lateral structures.
文摘Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.
文摘Posidonia oceanicameadows are experiencing a progressive decline, and monitoring their status is crucial for the maintenance of theseecosystems. We performed a comparativeanalysis of bed density, total phenol content and protein expression pattern to assess the conservation status ofPosidoniaplants from the S. Marinella (Rome, Italy) meadow. The total phenol content was inversely related to maximum beddensity, confirming the relationship betweenhigh phenol content and stressful conditions. In addition, protein expression pattern profilesshowed that the number of differentially expressed proteins was dramatically reduced in the latest years compared to previous analyses. Our results support the usefulness of integrating solid descriptors, such as phenol content, with novel biochemical/molecular approaches in the monitoring of meadows.
文摘Traffic flows form a complex system, especially in the context of urban sprawl. Direct estimation of traffic flows requires significant efforts and knowing in advance where to focus the study and where to place tools to directly measure traffic flows, and consequently traffic congestion could lead to significant savings in time and money. In the case of Rome municipality, we have monitored a situation in which a very high rate of urban fragmentation has occurred in the last 30 years, making the direct estimation of traffic difficult. The work described here can help to solve the problem of estimating traffic flows and in particular the congestion phenomenon through a very cheap approach by using remote sensing and geographical information system technology. This method is based on the identification of attractor points that draw traffic flows such as malls, schools, offices, shops, etc. that is to say, points in a territory that attract a certain number of people with vehicles (estimated with a scale) in specific periods of the day. The identification of those points and the calculation of the urban density through the satellite image processing have allowed the creation of a congestion map for the study area. Then the road network and the buildings have been classified according to the congestion values. The results highlight the most critical and congested areas that affect the traffic flows and impact the quality of life.
