This paper introduces a solution to the secure requirement for digital rights management （DRM） by the way of geospacial access control named geospacial access control （GeoAC） in geospacial field. The issues of aut...This paper introduces a solution to the secure requirement for digital rights management （DRM） by the way of geospacial access control named geospacial access control （GeoAC） in geospacial field. The issues of authorization for geospacial DRM are concentrated on. To geospacial DRM, one aspect is the declaration and enforcement of access rights, based on geographic aspects. To the approbation of digital geographic content, it is important to adopt online access to geodata through a special data infrastructure （SDI）. This results in the interoperability requirements on three different levels： data model level, service level and access control level. The interaction between the data model and service level can be obtained by criterions of the open geospacial consortium （OGC）, and the interaction of the access control level may be reached by declaring and enforcing access restrictions in GeoAC. Then an archetype enforcement based on GeoAC is elucidated. As one aspect of performing usage rights, the execution of access restrictions as an extension to a regular SDI is illuminated.展开更多
Zeolite catalysts,such as H-mordenite(H-MOR),are readily deactivated by coke deposition in carbonylation reactions.Pyridine modification of H-MOR can improve its stability but can lead to an undesirable loss in cataly...Zeolite catalysts,such as H-mordenite(H-MOR),are readily deactivated by coke deposition in carbonylation reactions.Pyridine modification of H-MOR can improve its stability but can lead to an undesirable loss in catalytic activity.Herein,we report the intrinsic impact of the pyridine adsorption behavior on H-MOR and the spacial hindrance of the zeolite frameworks on dimethyl ether(DME)carbonylation at a molecular level.We discovered that acid sites at O2 positions,located on common walls of eight-membered ring(8-MR)side pockets and 12-MR channels,were active in DME carbonylation,but were unfortunately poisoned during pyridine modification.Density functional theory calculations revealed that the pyridine-poisoned acid sites at the O2 positions could be easily regenerated due to the spacial hindrance of the zeolite frameworks.Accordingly,they can be facilely regenerated by proper thermal treatment,which induces 60%promotion in the catalytic activity along with a high stability.Our findings demonstrate the determining role of O2 positions in H-MOR for DME carbonylation and provide a new avenue for the rational design of other efficient zeolite-relevant catalytic systems.展开更多
Horizontal and veftical distributions of fine root abundance (mass per unit ground surface arca) were investi-gated in a densely planted larch - ash -stripe - mixed tbrest on dark broxvn forest soil in northeast China...Horizontal and veftical distributions of fine root abundance (mass per unit ground surface arca) were investi-gated in a densely planted larch - ash -stripe - mixed tbrest on dark broxvn forest soil in northeast China. There was evidencefor some degree of below-ground niche partitioning (or differentiation) betmpen the two species in hoth the horizontal andvertical directions. The ash fine roots largely penetrated into the larch belt (larch Sub-community) in surttrce soil (0-20 cm),indicating a possible inductive effect of larch ecological field on ash roots, while the penetration of larch tine roots into ashbelt (ash sub-community) was much restricted- which reflected a negative influence of ash ccological tield on Iarch roots. Inthe vertical direction of marginal soil the ash tine roots were mainly distributed in topsoil with a vertical gradient similar tothat as in the internal ash sub-community. but the larch fine roots were relatively compelled to deepcr soil layers by the com-petition (or exclusion) of marginal ash trees. All the dit1brences or complemcntarity wcre considered to the result of inter-specitic competition, which was important to the coexistence of the two tbrest species and the sustainability of mixed planta-tion.展开更多
This paper analyses the spacial distribution, quantity-scale, function-structure and facilities from the angle of spacial organizational optimizing theory and sustainable development thought. The authors point out the...This paper analyses the spacial distribution, quantity-scale, function-structure and facilities from the angle of spacial organizational optimizing theory and sustainable development thought. The authors point out the distributional principles of rural settlements in plain areas, and put forward planning and distribution of various levels of rural settlements (central villages, basic villages and natural villages).展开更多
Mainly applying Michel Foucault’s idea about spacial discipline plus gender studies,in particular,of the correlation between gender and space as well as the power hierarchy in the distribution of space,this paper ana...Mainly applying Michel Foucault’s idea about spacial discipline plus gender studies,in particular,of the correlation between gender and space as well as the power hierarchy in the distribution of space,this paper analyzes the female protagonist Miss Amelia in Carson McCullers’s The Ballad of the Sad Café.This paper argues that Amelia utilizes space as a means of self-empowerment,challenging the conventional gender dichotomy sanctioned by patriarchal norms.However,her spacial transgression is seen as a deconstruction of gender conventionality and causes masculine crisis as embodied by the male characters Marvin Macy and Cousin Lymon.As spacial discipline is collaboratively exerted by Macy and Lymon on Amelia to“correct”her transgression,Amelia finally concedes defeat and submits to patriarchal gender norms.展开更多
Carbon accumulation and distribution were studied in three plots of a 13 years old Chinese fir （Cunninghamia lanceolata） forest in Daqingshan,Guangxi. The results showed that the average carbon concentration in all ...Carbon accumulation and distribution were studied in three plots of a 13 years old Chinese fir （Cunninghamia lanceolata） forest in Daqingshan,Guangxi. The results showed that the average carbon concentration in all organs was in the following order: leaf （510.5）>bark （501.8）>wood （485.1）>root （476.5）>branch（462.1） （g·kg -1 ）. The carbon concentration of soil （to 60 cm depth） ranged from 11.4 to 21.1 （g·kg -1 ）,with an average of 16.6 （g·kg -1 ）. Carbon concentration of surface soil （to 20 cm） was higher than the other layer. The average carbon concentrations （g·kg -1 ） in different layers were in the order as: trees （497）> shrub （437.5） >standing litters （437.5）>herb （407.8）. The carbon storage of the forest ecosystem was in order of soil layer>vegetation >standing litter. Of total average carbon,23.87% was in vegetation component,74.27% in soil （60 cm depth）,and only 1.86% in standing ground litter layer. The tree layer occupied 22.93% of total carbon storage in the ecosystem and 96.07% of carbon storage in the vegetation layer. The carbon storage in different organs was positively related to the biomass of corresponding organs. Trunk accumulated the highest carbon storage,comprising 58.40% of carbon storage in tree layer. Secondly,root made up 20.09% of total tree carbon. The annual net productivity of Chinese fir plantation was 10.10 t·hm -2 a -1 ,stored carbon up to 4.67 t·hm -2 a -1 ,equal to 17.13 t·hm -2 a -1 of CO2. Chinese fir plantation was an important sink of atmospheric CO2. But its capacity of C sequestration decreased gradually in this region.展开更多
基金Funded by the Large-Scale Security SoC Project of Wuhan Science and Technology Bureau of China (No. 20061005119).
文摘This paper introduces a solution to the secure requirement for digital rights management （DRM） by the way of geospacial access control named geospacial access control （GeoAC） in geospacial field. The issues of authorization for geospacial DRM are concentrated on. To geospacial DRM, one aspect is the declaration and enforcement of access rights, based on geographic aspects. To the approbation of digital geographic content, it is important to adopt online access to geodata through a special data infrastructure （SDI）. This results in the interoperability requirements on three different levels： data model level, service level and access control level. The interaction between the data model and service level can be obtained by criterions of the open geospacial consortium （OGC）, and the interaction of the access control level may be reached by declaring and enforcing access restrictions in GeoAC. Then an archetype enforcement based on GeoAC is elucidated. As one aspect of performing usage rights, the execution of access restrictions as an extension to a regular SDI is illuminated.
基金supported by the National Natural Science Foundation of China(21476159,21676182)~~
文摘Zeolite catalysts,such as H-mordenite(H-MOR),are readily deactivated by coke deposition in carbonylation reactions.Pyridine modification of H-MOR can improve its stability but can lead to an undesirable loss in catalytic activity.Herein,we report the intrinsic impact of the pyridine adsorption behavior on H-MOR and the spacial hindrance of the zeolite frameworks on dimethyl ether(DME)carbonylation at a molecular level.We discovered that acid sites at O2 positions,located on common walls of eight-membered ring(8-MR)side pockets and 12-MR channels,were active in DME carbonylation,but were unfortunately poisoned during pyridine modification.Density functional theory calculations revealed that the pyridine-poisoned acid sites at the O2 positions could be easily regenerated due to the spacial hindrance of the zeolite frameworks.Accordingly,they can be facilely regenerated by proper thermal treatment,which induces 60%promotion in the catalytic activity along with a high stability.Our findings demonstrate the determining role of O2 positions in H-MOR for DME carbonylation and provide a new avenue for the rational design of other efficient zeolite-relevant catalytic systems.
文摘Horizontal and veftical distributions of fine root abundance (mass per unit ground surface arca) were investi-gated in a densely planted larch - ash -stripe - mixed tbrest on dark broxvn forest soil in northeast China. There was evidencefor some degree of below-ground niche partitioning (or differentiation) betmpen the two species in hoth the horizontal andvertical directions. The ash fine roots largely penetrated into the larch belt (larch Sub-community) in surttrce soil (0-20 cm),indicating a possible inductive effect of larch ecological field on ash roots, while the penetration of larch tine roots into ashbelt (ash sub-community) was much restricted- which reflected a negative influence of ash ccological tield on Iarch roots. Inthe vertical direction of marginal soil the ash tine roots were mainly distributed in topsoil with a vertical gradient similar tothat as in the internal ash sub-community. but the larch fine roots were relatively compelled to deepcr soil layers by the com-petition (or exclusion) of marginal ash trees. All the dit1brences or complemcntarity wcre considered to the result of inter-specitic competition, which was important to the coexistence of the two tbrest species and the sustainability of mixed planta-tion.
基金Under the auspices of the National Natural Science Foundation of China (No.49771031)51-A1-204, KZ95T-06).
文摘This paper analyses the spacial distribution, quantity-scale, function-structure and facilities from the angle of spacial organizational optimizing theory and sustainable development thought. The authors point out the distributional principles of rural settlements in plain areas, and put forward planning and distribution of various levels of rural settlements (central villages, basic villages and natural villages).
文摘Mainly applying Michel Foucault’s idea about spacial discipline plus gender studies,in particular,of the correlation between gender and space as well as the power hierarchy in the distribution of space,this paper analyzes the female protagonist Miss Amelia in Carson McCullers’s The Ballad of the Sad Café.This paper argues that Amelia utilizes space as a means of self-empowerment,challenging the conventional gender dichotomy sanctioned by patriarchal norms.However,her spacial transgression is seen as a deconstruction of gender conventionality and causes masculine crisis as embodied by the male characters Marvin Macy and Cousin Lymon.As spacial discipline is collaboratively exerted by Macy and Lymon on Amelia to“correct”her transgression,Amelia finally concedes defeat and submits to patriarchal gender norms.
文摘Carbon accumulation and distribution were studied in three plots of a 13 years old Chinese fir （Cunninghamia lanceolata） forest in Daqingshan,Guangxi. The results showed that the average carbon concentration in all organs was in the following order: leaf （510.5）>bark （501.8）>wood （485.1）>root （476.5）>branch（462.1） （g·kg -1 ）. The carbon concentration of soil （to 60 cm depth） ranged from 11.4 to 21.1 （g·kg -1 ）,with an average of 16.6 （g·kg -1 ）. Carbon concentration of surface soil （to 20 cm） was higher than the other layer. The average carbon concentrations （g·kg -1 ） in different layers were in the order as: trees （497）> shrub （437.5） >standing litters （437.5）>herb （407.8）. The carbon storage of the forest ecosystem was in order of soil layer>vegetation >standing litter. Of total average carbon,23.87% was in vegetation component,74.27% in soil （60 cm depth）,and only 1.86% in standing ground litter layer. The tree layer occupied 22.93% of total carbon storage in the ecosystem and 96.07% of carbon storage in the vegetation layer. The carbon storage in different organs was positively related to the biomass of corresponding organs. Trunk accumulated the highest carbon storage,comprising 58.40% of carbon storage in tree layer. Secondly,root made up 20.09% of total tree carbon. The annual net productivity of Chinese fir plantation was 10.10 t·hm -2 a -1 ,stored carbon up to 4.67 t·hm -2 a -1 ,equal to 17.13 t·hm -2 a -1 of CO2. Chinese fir plantation was an important sink of atmospheric CO2. But its capacity of C sequestration decreased gradually in this region.
