The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis...The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus.展开更多
In complex networks,identifying influential spreader is of great significance for improving the reliability of networks and ensuring the safe and effective operation of networks.Nowadays,it is widely used in power net...In complex networks,identifying influential spreader is of great significance for improving the reliability of networks and ensuring the safe and effective operation of networks.Nowadays,it is widely used in power networks,aviation networks,computer networks,and social networks,and so on.Traditional centrality methods mainly include degree centrality,closeness centrality,betweenness centrality,eigenvector centrality,k-shell,etc.However,single centrality method is onesided and inaccurate,and sometimes many nodes have the same centrality value,namely the same ranking result,which makes it difficult to distinguish between nodes.According to several classical methods of identifying influential nodes,in this paper we propose a novel method that is more full-scaled and universally applicable.Taken into account in this method are several aspects of node’s properties,including local topological characteristics,central location of nodes,propagation characteristics,and properties of neighbor nodes.In view of the idea of the multi-attribute decision-making,we regard the basic centrality method as node’s attribute and use the entropy weight method to weigh different attributes,and obtain node’s combined centrality.Then,the combined centrality is applied to the gravity law to comprehensively identify influential nodes in networks.Finally,the classical susceptible-infected-recovered(SIR)model is used to simulate the epidemic spreading in six real-society networks.Our proposed method not only considers the four topological properties of nodes,but also emphasizes the influence of neighbor nodes from the aspect of gravity.It is proved that the new method can effectively overcome the disadvantages of single centrality method and increase the accuracy of identifying influential nodes,which is of great significance for monitoring and controlling the complex networks.展开更多
Surface and borehole gravity data contain complementary information.Thus,the joint inversion of these two data types can help retrieve the real spatial distributions of density bodies.When a sharp boundary exists betw...Surface and borehole gravity data contain complementary information.Thus,the joint inversion of these two data types can help retrieve the real spatial distributions of density bodies.When a sharp boundary exists between an anomalous density body and its surrounding rock,the interface recovered by smooth inversion with Tikhonov regularization is not clear,leading to difficulties in the subsequent geological interpretation.In this work,we develop a joint inversion of surface and borehole gravity data using zeroth-order minimum entropy regularization.The method takes advantage of the complementary information from surface and borehole gravity data to enhance the imaging resolution of density bodies.It also produces a focused imaging of bodies through the zeroth-order minimum entropy regularization without requiring a preselection of a proper focusing parameter.We apply the developed joint inversion approach to three diff erent synthetic data sets.Inversion results show that the focusing inversion with the zeroth-order minimum entropy regularization provides a good description of the true spatial extent of anomalous density bodies.Meanwhile,the joint focusing inversion reconstructs a more reliable density model with a relatively high resolution when a density body is passed through by one or more boreholes.展开更多
【目的】研究香料烟在云南的气候适生区,为其合理种植提供理论依据。【方法】使用ArcGIS将气候数据结合地形校正进行协同克里金插值,利用最大熵(maximum entropy,MaxEnt)模型筛选影响香料烟分布的气象因子,最后使用ArcGIS对云南省香料...【目的】研究香料烟在云南的气候适生区,为其合理种植提供理论依据。【方法】使用ArcGIS将气候数据结合地形校正进行协同克里金插值,利用最大熵(maximum entropy,MaxEnt)模型筛选影响香料烟分布的气象因子,最后使用ArcGIS对云南省香料烟的气候适生区进行评价。【结果】MaxEnt模型的曲线下面积(the area under curve,AUC)值为0.993,可精准预测云南省香料烟的气候适生区。影响香料烟在云南省分布的气象因子为2月降雨量、1月日照时间、3月日照时间、3月平均气温、3月降雨量、4月降雨量、1月降雨量、2月日照时间和4月最高气温。香料烟在云南省的最适宜种植区(四级适生区)主要分布在保山、德宏和临沧;适宜种植区(三级适生区)主要分布在保山、德宏、临沧、玉溪、楚雄和大理。MaxEnt模型预测结果与香料烟种植区拟合度较高,其种植区主要分布在四级和三级适生区,极少数分布在二级和一级适生区。【结论】云南省适合种植香料烟的地区主要在西南部,适宜种植区主要为沿怒江、澜沧江、黑惠江及其支流的干热河谷地区。2月降雨量、1月日照时间、3月日照时间和3月平均气温是影响香料烟在云南种植的主要气象因子。展开更多
The WC/CoCrFeNiAl0.2 high-entropy alloy(HEA)composites were prepared through high-gravity combustion synthesis.The preparation method is presented below.First,using a designed suitable multiphase thermite system,the m...The WC/CoCrFeNiAl0.2 high-entropy alloy(HEA)composites were prepared through high-gravity combustion synthesis.The preparation method is presented below.First,using a designed suitable multiphase thermite system,the molten CoCrFeNiAl0.2 HEA was fabricated using low-cost metal oxides.The molten HEA was subsequently infiltrated into the WC layer to fabricate WC/CoCrFeNiAl0.2 composites in a highgravity field.The porosity of the WC/CoCrFeNiAl0.2 composites was down-regulated,and their compressive yield strength was up-regulated when the high-gravity field was increased from 600g to 1500g because this infiltration process of a HEA melt into the WC layer is driven by centrifugal force.The WC particles in the composites exhibited a gradient distribution along the direction of the centrifugal force,which was attributed to the combined action of the high-gravity field and the temperature gradient field.The Vickers hardness of the sample was down-regulated from 9.53 to 7.41 GPa along the direction of the centrifugal force.展开更多
In this assignment we will present a reconstruction scheme between f(R) gravity with ordinary and entropy corrected(m, n)-type holographic dark energy. The correspondence is established and expressions for the reconst...In this assignment we will present a reconstruction scheme between f(R) gravity with ordinary and entropy corrected(m, n)-type holographic dark energy. The correspondence is established and expressions for the reconstructed f(R) models are determined. To study the evolution of the reconstructed models plots are generated. The stability of the calculated models are also investigated using the squared speed of sound in the background of the reconstructed gravities.展开更多
藏酋猴仅在中国有分布,是中国特有种及国家二级重点保护野生动物,根据世界自然保护联盟濒危物种红色名录(IUCN Red List of Threatened Species),其属于近危物种。为了解湖南莽山国家级自然保护区内藏酋猴的生存情况,为该保护区未来藏...藏酋猴仅在中国有分布,是中国特有种及国家二级重点保护野生动物,根据世界自然保护联盟濒危物种红色名录(IUCN Red List of Threatened Species),其属于近危物种。为了解湖南莽山国家级自然保护区内藏酋猴的生存情况,为该保护区未来藏酋猴的野外保护工作提供参考,对湖南莽山国家级自然保护区内藏酋猴的栖息地进行了适宜性研究和评价。首先,于2020年1月至2023年9月在保护区内共布设红外相机69台,通过红外相机监测,共记录到37个藏酋猴的有效位点。随后,基于这些数据,利用最大熵(maximum entropy,MaxEnt)模型分析了保护区内藏酋猴的生境适宜性,并预测了其潜在适宜栖息地。结果显示:模型受试者操作特征(receiver operating characteristic,ROC)曲线重复运行10次的平均曲线下面积(area under the curve,AUC)为0.930,说明预测结果极准确。距河流距离(disriver_ms)、等温性(bio3)、距竹林距离(disbamf_ms)、海拔(altitude_ms)、距道路距离(disroad_ms)、最干季度平均温度(bio9)是影响藏酋猴适宜栖息地分布的主要环境变量,其栖息地选择偏好为海拔在644~910 m和1094~1750 m的靠近河流的竹林。保护区内藏酋猴的总适生区面积为105.1149 km^(2),占研究地总面积的53%;非适生区面积为93.2151 km^(2),占研究地总面积的47%,其适宜栖息地主要分布在坪坑、红旗桥、十八支线、相思坑、竹坑、南门庄、泽子坪等区域。展开更多
By employing the replica trick,we study the impact of the replica parameter n on the modular entropy and the capacity of entanglement in the End of the World(EoW)model and the island model,respectively.For the EoW mod...By employing the replica trick,we study the impact of the replica parameter n on the modular entropy and the capacity of entanglement in the End of the World(EoW)model and the island model,respectively.For the EoW model,we present n-dependent evolution curves of the modular entropy and the capacity of entanglement under both microcanonical and canonical ensembles.In particular,in the canonical ensemble,all quantities decrease as n increases at late times.For the island model,we develop the replica geometry for finite n and re-evaluate the modular entropy and the capacity of entanglement in a two-sided eternal Jackiw-Teitelboim black hole coupled with a thermal bath.In the case of a single island configuration,the modular entropy and capacity of entanglement closely resemble the thermal entropy and the heat capacity,respectively,yielding results analogous to those obtained in the canonical ensemble for the EoW model.The analysis of the results from these two models strongly indicates that in geometries with a greater number of n copies,more connected geometries effectively purify thermal Hawking radiation.In addition,we compare these findings with statistical mechanics and provide an interpretation for the replica parameter n.Finally,we generalize the island formula to accommodate the finite n case under this interpretation.展开更多
基金the auspices of A Category of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA20010101)。
文摘The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus.
基金Project support by the National Key Research and Development Program of China(Grant No.2018YFF0301000)the National Natural Science Foundation of China(Grant Nos.71673161 and 71790613)。
文摘In complex networks,identifying influential spreader is of great significance for improving the reliability of networks and ensuring the safe and effective operation of networks.Nowadays,it is widely used in power networks,aviation networks,computer networks,and social networks,and so on.Traditional centrality methods mainly include degree centrality,closeness centrality,betweenness centrality,eigenvector centrality,k-shell,etc.However,single centrality method is onesided and inaccurate,and sometimes many nodes have the same centrality value,namely the same ranking result,which makes it difficult to distinguish between nodes.According to several classical methods of identifying influential nodes,in this paper we propose a novel method that is more full-scaled and universally applicable.Taken into account in this method are several aspects of node’s properties,including local topological characteristics,central location of nodes,propagation characteristics,and properties of neighbor nodes.In view of the idea of the multi-attribute decision-making,we regard the basic centrality method as node’s attribute and use the entropy weight method to weigh different attributes,and obtain node’s combined centrality.Then,the combined centrality is applied to the gravity law to comprehensively identify influential nodes in networks.Finally,the classical susceptible-infected-recovered(SIR)model is used to simulate the epidemic spreading in six real-society networks.Our proposed method not only considers the four topological properties of nodes,but also emphasizes the influence of neighbor nodes from the aspect of gravity.It is proved that the new method can effectively overcome the disadvantages of single centrality method and increase the accuracy of identifying influential nodes,which is of great significance for monitoring and controlling the complex networks.
基金financially supported by the National Key Research and Development Program of China(no.2018YFC0603300)the National Natural Science Foundation of China(no.42004054)。
文摘Surface and borehole gravity data contain complementary information.Thus,the joint inversion of these two data types can help retrieve the real spatial distributions of density bodies.When a sharp boundary exists between an anomalous density body and its surrounding rock,the interface recovered by smooth inversion with Tikhonov regularization is not clear,leading to difficulties in the subsequent geological interpretation.In this work,we develop a joint inversion of surface and borehole gravity data using zeroth-order minimum entropy regularization.The method takes advantage of the complementary information from surface and borehole gravity data to enhance the imaging resolution of density bodies.It also produces a focused imaging of bodies through the zeroth-order minimum entropy regularization without requiring a preselection of a proper focusing parameter.We apply the developed joint inversion approach to three diff erent synthetic data sets.Inversion results show that the focusing inversion with the zeroth-order minimum entropy regularization provides a good description of the true spatial extent of anomalous density bodies.Meanwhile,the joint focusing inversion reconstructs a more reliable density model with a relatively high resolution when a density body is passed through by one or more boreholes.
文摘【目的】研究香料烟在云南的气候适生区,为其合理种植提供理论依据。【方法】使用ArcGIS将气候数据结合地形校正进行协同克里金插值,利用最大熵(maximum entropy,MaxEnt)模型筛选影响香料烟分布的气象因子,最后使用ArcGIS对云南省香料烟的气候适生区进行评价。【结果】MaxEnt模型的曲线下面积(the area under curve,AUC)值为0.993,可精准预测云南省香料烟的气候适生区。影响香料烟在云南省分布的气象因子为2月降雨量、1月日照时间、3月日照时间、3月平均气温、3月降雨量、4月降雨量、1月降雨量、2月日照时间和4月最高气温。香料烟在云南省的最适宜种植区(四级适生区)主要分布在保山、德宏和临沧;适宜种植区(三级适生区)主要分布在保山、德宏、临沧、玉溪、楚雄和大理。MaxEnt模型预测结果与香料烟种植区拟合度较高,其种植区主要分布在四级和三级适生区,极少数分布在二级和一级适生区。【结论】云南省适合种植香料烟的地区主要在西南部,适宜种植区主要为沿怒江、澜沧江、黑惠江及其支流的干热河谷地区。2月降雨量、1月日照时间、3月日照时间和3月平均气温是影响香料烟在云南种植的主要气象因子。
基金financially supported by the National Key R&D Program of China (No. 2017YFB0310303)the National Natural Science Foundation of China (No. 51702332)the Key Laboratory of Cryogenics, TIPC, CAS (Nos. CRYOQN201705 and CRYOQN201507)
文摘The WC/CoCrFeNiAl0.2 high-entropy alloy(HEA)composites were prepared through high-gravity combustion synthesis.The preparation method is presented below.First,using a designed suitable multiphase thermite system,the molten CoCrFeNiAl0.2 HEA was fabricated using low-cost metal oxides.The molten HEA was subsequently infiltrated into the WC layer to fabricate WC/CoCrFeNiAl0.2 composites in a highgravity field.The porosity of the WC/CoCrFeNiAl0.2 composites was down-regulated,and their compressive yield strength was up-regulated when the high-gravity field was increased from 600g to 1500g because this infiltration process of a HEA melt into the WC layer is driven by centrifugal force.The WC particles in the composites exhibited a gradient distribution along the direction of the centrifugal force,which was attributed to the combined action of the high-gravity field and the temperature gradient field.The Vickers hardness of the sample was down-regulated from 9.53 to 7.41 GPa along the direction of the centrifugal force.
文摘In this assignment we will present a reconstruction scheme between f(R) gravity with ordinary and entropy corrected(m, n)-type holographic dark energy. The correspondence is established and expressions for the reconstructed f(R) models are determined. To study the evolution of the reconstructed models plots are generated. The stability of the calculated models are also investigated using the squared speed of sound in the background of the reconstructed gravities.
文摘藏酋猴仅在中国有分布,是中国特有种及国家二级重点保护野生动物,根据世界自然保护联盟濒危物种红色名录(IUCN Red List of Threatened Species),其属于近危物种。为了解湖南莽山国家级自然保护区内藏酋猴的生存情况,为该保护区未来藏酋猴的野外保护工作提供参考,对湖南莽山国家级自然保护区内藏酋猴的栖息地进行了适宜性研究和评价。首先,于2020年1月至2023年9月在保护区内共布设红外相机69台,通过红外相机监测,共记录到37个藏酋猴的有效位点。随后,基于这些数据,利用最大熵(maximum entropy,MaxEnt)模型分析了保护区内藏酋猴的生境适宜性,并预测了其潜在适宜栖息地。结果显示:模型受试者操作特征(receiver operating characteristic,ROC)曲线重复运行10次的平均曲线下面积(area under the curve,AUC)为0.930,说明预测结果极准确。距河流距离(disriver_ms)、等温性(bio3)、距竹林距离(disbamf_ms)、海拔(altitude_ms)、距道路距离(disroad_ms)、最干季度平均温度(bio9)是影响藏酋猴适宜栖息地分布的主要环境变量,其栖息地选择偏好为海拔在644~910 m和1094~1750 m的靠近河流的竹林。保护区内藏酋猴的总适生区面积为105.1149 km^(2),占研究地总面积的53%;非适生区面积为93.2151 km^(2),占研究地总面积的47%,其适宜栖息地主要分布在坪坑、红旗桥、十八支线、相思坑、竹坑、南门庄、泽子坪等区域。
基金supported by National Basic Research Program of China (973 Program,2002CB111405)the National Nature Science Foundation ofChina (30471162, 30671394)the National Key Technologies Research and Development Program of China(2006BAD08A13)~~
基金supported by National Natural Science Foundation of China,China(Grant Nos.12275166 and 12311540141).
文摘By employing the replica trick,we study the impact of the replica parameter n on the modular entropy and the capacity of entanglement in the End of the World(EoW)model and the island model,respectively.For the EoW model,we present n-dependent evolution curves of the modular entropy and the capacity of entanglement under both microcanonical and canonical ensembles.In particular,in the canonical ensemble,all quantities decrease as n increases at late times.For the island model,we develop the replica geometry for finite n and re-evaluate the modular entropy and the capacity of entanglement in a two-sided eternal Jackiw-Teitelboim black hole coupled with a thermal bath.In the case of a single island configuration,the modular entropy and capacity of entanglement closely resemble the thermal entropy and the heat capacity,respectively,yielding results analogous to those obtained in the canonical ensemble for the EoW model.The analysis of the results from these two models strongly indicates that in geometries with a greater number of n copies,more connected geometries effectively purify thermal Hawking radiation.In addition,we compare these findings with statistical mechanics and provide an interpretation for the replica parameter n.Finally,we generalize the island formula to accommodate the finite n case under this interpretation.
