The determination of the geographical origin as well as the adulteration of natural products is a technical problem due to similar chemical composition between an adulterant and the original. It is assumed that tartar...The determination of the geographical origin as well as the adulteration of natural products is a technical problem due to similar chemical composition between an adulterant and the original. It is assumed that tartaric acid comes from natural sources, however there is no specific regulation for this claim. This paper describes the use of isotope mass spectrometry associated with chemometrics to classify different samples of tartaric acid. The results showed that the variables δ^13C, δ^18O and δ^2H allowed the discrimination of tartaric acid samples by geographical origin and production method. By using a combination of chemometfic analysis it was possible to confirm a notoriousseparation of the samples. Thus, this is a promising method to be applied in the quality control and authenticity of tartaric acid.展开更多
Focusing on international relations from the perspective of geography, geopolitics exerts powerful influences on the course of economic and political development in the world. In the tide of globalization and informat...Focusing on international relations from the perspective of geography, geopolitics exerts powerful influences on the course of economic and political development in the world. In the tide of globalization and information technology, geopolitics has become an important subject for global pattern interpretation and policy making. It is essentially important to have a scientific and systematic review on international geopolitics to promote its development. Based on the bibliometric statistics, the paper reviews the research development of geopolitics on the Web of Science from 1996 to 2015. The history, journals, papers and key research areas of geopolitics have been revealed in the paper. By the analysis of bibliometric statistics, the number of papers recently published in the journals of political geography and related geography journals continues to increase. The key areas of geopolitical papers which are globally highly cited include geopolitical interpretation of the countries and borders, critical geopolitics, emotional geopolitics, feminist geopolitics and other topics. Before the year of 2000, the state and borders were hot topics of the geopolitical research. Yet since 2000, it has been the trend that the geopolitics is increasingly set in the context of geographical implications. At the same time, critical geopolitics appears to be the main area of geopolitical research, especially transitioning from traditional geopolitics towards the humanism-embeddedness(such as emotional geopolitics, feminist geopolitics). The paper then systematically reviews the branch trends of geopolitical research, including the borders and the territory, global geo-culture and geo-economics, Chinese models of geopolitics, resource conflicts and ecological politics, as well as emotional geopolitics. Finally, it puts forward the implication that Chinese geopolitical studies should reinforce the importance of geographical space and scale, use the process of description and multiple methods, as well as integrate humanistic thoughts, in order to further enrich the theories and practices of geopolitical research.展开更多
The determination of the gravitational potential of a prism plays an important role in physical geodesy and geophysics. However, there are few literatures that provide accurate approaches for determining the gravitati...The determination of the gravitational potential of a prism plays an important role in physical geodesy and geophysics. However, there are few literatures that provide accurate approaches for determining the gravitational potential of a prism. Discrete element method can be used to determine the gravitational potential of a prism, and can approximate the true gravitational potential values with sufficient accuracy (the smaller each element is, the more accurate the result is). Although Nagy's approach provided a closed expression, one does not know whether it is valid, due to the fact that this approach has not been confirmed in literatures. In this paper, a study on the comparison of Nagy's approach with discrete element method is presented. The results show that Nagy's formulas for determining the gravitational potential of a prism are valid in the domain both inside and outside the prism.展开更多
文摘The determination of the geographical origin as well as the adulteration of natural products is a technical problem due to similar chemical composition between an adulterant and the original. It is assumed that tartaric acid comes from natural sources, however there is no specific regulation for this claim. This paper describes the use of isotope mass spectrometry associated with chemometrics to classify different samples of tartaric acid. The results showed that the variables δ^13C, δ^18O and δ^2H allowed the discrimination of tartaric acid samples by geographical origin and production method. By using a combination of chemometfic analysis it was possible to confirm a notoriousseparation of the samples. Thus, this is a promising method to be applied in the quality control and authenticity of tartaric acid.
基金National Natural Science Foundation of China,No.41530634,No.41530751
文摘Focusing on international relations from the perspective of geography, geopolitics exerts powerful influences on the course of economic and political development in the world. In the tide of globalization and information technology, geopolitics has become an important subject for global pattern interpretation and policy making. It is essentially important to have a scientific and systematic review on international geopolitics to promote its development. Based on the bibliometric statistics, the paper reviews the research development of geopolitics on the Web of Science from 1996 to 2015. The history, journals, papers and key research areas of geopolitics have been revealed in the paper. By the analysis of bibliometric statistics, the number of papers recently published in the journals of political geography and related geography journals continues to increase. The key areas of geopolitical papers which are globally highly cited include geopolitical interpretation of the countries and borders, critical geopolitics, emotional geopolitics, feminist geopolitics and other topics. Before the year of 2000, the state and borders were hot topics of the geopolitical research. Yet since 2000, it has been the trend that the geopolitics is increasingly set in the context of geographical implications. At the same time, critical geopolitics appears to be the main area of geopolitical research, especially transitioning from traditional geopolitics towards the humanism-embeddedness(such as emotional geopolitics, feminist geopolitics). The paper then systematically reviews the branch trends of geopolitical research, including the borders and the territory, global geo-culture and geo-economics, Chinese models of geopolitics, resource conflicts and ecological politics, as well as emotional geopolitics. Finally, it puts forward the implication that Chinese geopolitical studies should reinforce the importance of geographical space and scale, use the process of description and multiple methods, as well as integrate humanistic thoughts, in order to further enrich the theories and practices of geopolitical research.
基金Supported by the National Natural Science Foundation of China (No.40637034, 40974015)the National 863 Program of China (No.2006AA12Z211)
文摘The determination of the gravitational potential of a prism plays an important role in physical geodesy and geophysics. However, there are few literatures that provide accurate approaches for determining the gravitational potential of a prism. Discrete element method can be used to determine the gravitational potential of a prism, and can approximate the true gravitational potential values with sufficient accuracy (the smaller each element is, the more accurate the result is). Although Nagy's approach provided a closed expression, one does not know whether it is valid, due to the fact that this approach has not been confirmed in literatures. In this paper, a study on the comparison of Nagy's approach with discrete element method is presented. The results show that Nagy's formulas for determining the gravitational potential of a prism are valid in the domain both inside and outside the prism.
