Strong low-frequency energy beneath a hydrocarbon reservoir is called a seismic low-frequency shadow and can be used as a hydrocarbon indicator （Tarter et al., 1979） bu the physical mechanism of the observed low-fre...Strong low-frequency energy beneath a hydrocarbon reservoir is called a seismic low-frequency shadow and can be used as a hydrocarbon indicator （Tarter et al., 1979） bu the physical mechanism of the observed low-frequency shadow is still unclear. To stud） the mechanism, we performed seismic numerical simulation of geological models with a hydrocarbon-bearing zone using the 2-D diffusive-viscous wave equation which car effectively model the characteristics of velocity dispersion and transform the seismic dat~ centered in a target layer slice within a time window to the time-frequency domain by usinl time-frequency signal analysis and sort the frequency gathers to common frequency cubes. Then, we observe the characteristics of the seismic low-frequency shadow in the common frequency cubes. The numerical simulations reveal that the main mechanism of seismic lowfrequency shadows is attributed to high attenuation of the medium to high seismic frequency components caused by absorption in the hydrocarbon-filled reservoir. Results from a practical example of seismic low-frequency shadows show that it is possible to identify the reservoir by the low-frequency shadow with high S/N seismic data.展开更多
This paper tries to apply a new and more comprehensive method to urban tourism research in an expanded field instead of only partially, unilaterally and separately focusing on the city itself. Taking the urban tourism...This paper tries to apply a new and more comprehensive method to urban tourism research in an expanded field instead of only partially, unilaterally and separately focusing on the city itself. Taking the urban tourism of Guangdong, Hong Kong and Macao as an example, it aims at presenting a new spatial system of urban tourism research and pointing out the new orientation of urban tourism research in combination of macro level and micro level, from description to explanation. The meanings of the spatial framework construction for urban tourism study are to make clear how urban tourism studies vary with the changes of dimensions of time and space. This is a meaningful discussion because it will bring great changes to the using of literatures, the opening of research perspectives on urban tourism and the upgrading of theories, so as to create a new stage for urban tourism study.展开更多
As we are in the knowledge economy, the main purpose of this research is to define the value of relational capital by measuring it with an innovative model. To this end, this paper will explain the meaning of intellec...As we are in the knowledge economy, the main purpose of this research is to define the value of relational capital by measuring it with an innovative model. To this end, this paper will explain the meaning of intellectual capital （human capital, structural capital, and relational capital） in the field of knowledge economy and what relational capital is and how we can measure its value. The research is qualitative in nature and was developed through the study of the international literature. The research presents some theoretical evidences that permit defining a method for the evaluation of relational capital. In this direction, the above method will need to have some integration in the future research. Moreover, this approach should consider some empirical evidences to establish the practical value of the method. In fact, the method presented encourages debate and a critical attitude towards the evaluations of relational capital and intellectual capital.展开更多
基金supported by the National Hi-tech Research and Development Program of China (863 Program) (Grant No. 2006AA0AA 02 - 2).
文摘Strong low-frequency energy beneath a hydrocarbon reservoir is called a seismic low-frequency shadow and can be used as a hydrocarbon indicator （Tarter et al., 1979） bu the physical mechanism of the observed low-frequency shadow is still unclear. To stud） the mechanism, we performed seismic numerical simulation of geological models with a hydrocarbon-bearing zone using the 2-D diffusive-viscous wave equation which car effectively model the characteristics of velocity dispersion and transform the seismic dat~ centered in a target layer slice within a time window to the time-frequency domain by usinl time-frequency signal analysis and sort the frequency gathers to common frequency cubes. Then, we observe the characteristics of the seismic low-frequency shadow in the common frequency cubes. The numerical simulations reveal that the main mechanism of seismic lowfrequency shadows is attributed to high attenuation of the medium to high seismic frequency components caused by absorption in the hydrocarbon-filled reservoir. Results from a practical example of seismic low-frequency shadows show that it is possible to identify the reservoir by the low-frequency shadow with high S/N seismic data.
基金Under the auspices of the National Natural Science Foundation of China (No .40201017)
文摘This paper tries to apply a new and more comprehensive method to urban tourism research in an expanded field instead of only partially, unilaterally and separately focusing on the city itself. Taking the urban tourism of Guangdong, Hong Kong and Macao as an example, it aims at presenting a new spatial system of urban tourism research and pointing out the new orientation of urban tourism research in combination of macro level and micro level, from description to explanation. The meanings of the spatial framework construction for urban tourism study are to make clear how urban tourism studies vary with the changes of dimensions of time and space. This is a meaningful discussion because it will bring great changes to the using of literatures, the opening of research perspectives on urban tourism and the upgrading of theories, so as to create a new stage for urban tourism study.
文摘As we are in the knowledge economy, the main purpose of this research is to define the value of relational capital by measuring it with an innovative model. To this end, this paper will explain the meaning of intellectual capital （human capital, structural capital, and relational capital） in the field of knowledge economy and what relational capital is and how we can measure its value. The research is qualitative in nature and was developed through the study of the international literature. The research presents some theoretical evidences that permit defining a method for the evaluation of relational capital. In this direction, the above method will need to have some integration in the future research. Moreover, this approach should consider some empirical evidences to establish the practical value of the method. In fact, the method presented encourages debate and a critical attitude towards the evaluations of relational capital and intellectual capital.
