Laboratory experiments were carried out to investigate the effect of freezing and thawing processes on wet aggregate stability （WAS） of black soil. Wet aggregate stability was determined by different aggregate size ...Laboratory experiments were carried out to investigate the effect of freezing and thawing processes on wet aggregate stability （WAS） of black soil. Wet aggregate stability was determined by different aggregate size groups, different water contents, various freeze-thaw cycles, and various freezing temperatures. The results showed that, when at suitable water content, aggregate stability was enhanced, aggregate sta-bility will be disrupted when moisture content is too high or too low, especially higher water content. Temperature also had a significant ef-fect, but moisture content determined the suitable freezing temperatures for a given soil. Water-stable aggregate （WSA〉0.5）, the total aggre-gate content, and mean weight diameter decreasing with the freeze-thaw cycles increase, reached to 5 percent significance level. The reason for crumbing aggregates is the water and air conflict, thus raising the hypothesis that water content affects the aggregate stability in the process of freezing and thawing.展开更多
The air transportation network, one of the common multilayer complex systems, is composed of a collection of individual airlines, and each airline corresponds to a different layer. An important question is then how ma...The air transportation network, one of the common multilayer complex systems, is composed of a collection of individual airlines, and each airline corresponds to a different layer. An important question is then how many airlines are really necessary to represent the optimal structure of a multilayer air transportation system. Here we take the Chinese air transportation network （CATN） as an example to explore the nature of multiplex systems through the procedure of network aggregation. Specifically, we propose a series of structural measures to characterize the CATN from the multilayered to the aggregated network level. We show how these measures evolve during the network aggregation process in which layers are gradually merged together and find that there is an evident structural transition that happened in the aggregated network with nine randomly chosen airlines merged, where the network features and construction cost of this network are almost equivalent to those of the present CATN with twenty-two airlines under this condition. These findings could shed some light on network structure optimization and management of the Chinese air transportation system.展开更多
The synthesis of two gold(I)complexes containing a pyridyl ligand with a polyethyleneglycol pendant arm at one position and a chromophore(aniline or coumarin)at the second coordination position is herein reported.Thes...The synthesis of two gold(I)complexes containing a pyridyl ligand with a polyethyleneglycol pendant arm at one position and a chromophore(aniline or coumarin)at the second coordination position is herein reported.These compounds have been observed to aggregate in acetonitrile/water mixtures and the results have been compared with two other gold(I)compounds previously synthesized by our group that contain a water soluble phosphane instead of the pyridyl ligand.We observed that the coumarin derivative is much more stable while the aniline analogue decomposes in the presence of small amounts of water.The aggregation of this coumarin gold(I)compound has been deeply studied by DLS,SAXS,optical microscopy and electron microscopy(SEM and cryo-TEM).The calculation of the crystal packing parameter confirms a vesicle-type assembly.In order to obtain more detailed information about the composition of vesicles,the number of molecules involved in the self-assembly process has been determined(Nagg=82).DFT calculations support these data,determining a size of around 90Åfor the vesicles,which may form coacervates to yield the larger structures observed under a microscope.展开更多
Cloud microphysical data observed with PMS probes have been combined with radar and other in-situ data collected by a NOAA P-3 aircraft that flew through the stratiform and transition regions of a mesoscale convective...Cloud microphysical data observed with PMS probes have been combined with radar and other in-situ data collected by a NOAA P-3 aircraft that flew through the stratiform and transition regions of a mesoscale convective complex(MCC).The combined data have been analyzed with respect to the mescscale structure of the storm systems.The characteristics of ice particles in the transition and stratiform regions were quite differeat.The ice particle concentrations in the transition region were about 4 to 6 times that found in the stratiform region,and the size of ice particles in the stratiform region was about twice that in the transition region.The relatively lower radar reflectivity in the transition region is a result of smaller particle sizes.The main precipitation particle growth mechanisms are riming and aggregation in the transition region ard the aggregation process predominates in the stratiform region referred from the microphysical structures.The ag- gregation starts in the upper,colder levls but becomes more efficient as the particles approach the melting layer.展开更多
基金National Basic Research Program of China (2005CB121101, 2005CB121103)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-407)
文摘Laboratory experiments were carried out to investigate the effect of freezing and thawing processes on wet aggregate stability （WAS） of black soil. Wet aggregate stability was determined by different aggregate size groups, different water contents, various freeze-thaw cycles, and various freezing temperatures. The results showed that, when at suitable water content, aggregate stability was enhanced, aggregate sta-bility will be disrupted when moisture content is too high or too low, especially higher water content. Temperature also had a significant ef-fect, but moisture content determined the suitable freezing temperatures for a given soil. Water-stable aggregate （WSA〉0.5）, the total aggre-gate content, and mean weight diameter decreasing with the freeze-thaw cycles increase, reached to 5 percent significance level. The reason for crumbing aggregates is the water and air conflict, thus raising the hypothesis that water content affects the aggregate stability in the process of freezing and thawing.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11405118,11401448 and 11301403
文摘The air transportation network, one of the common multilayer complex systems, is composed of a collection of individual airlines, and each airline corresponds to a different layer. An important question is then how many airlines are really necessary to represent the optimal structure of a multilayer air transportation system. Here we take the Chinese air transportation network （CATN） as an example to explore the nature of multiplex systems through the procedure of network aggregation. Specifically, we propose a series of structural measures to characterize the CATN from the multilayered to the aggregated network level. We show how these measures evolve during the network aggregation process in which layers are gradually merged together and find that there is an evident structural transition that happened in the aggregated network with nine randomly chosen airlines merged, where the network features and construction cost of this network are almost equivalent to those of the present CATN with twenty-two airlines under this condition. These findings could shed some light on network structure optimization and management of the Chinese air transportation system.
基金grateful to the Ministerio de Ciencia e Innovación of Spain(Projects PID2019-104121GB-I00 and PID2020-115637GB-I00)This work was supported by the Associate Laboratory for Green Chemistry-LAQV,which is financed by national funds from FCT/MCTES(UID/QUI/50006/2019)+2 种基金The authors would also like to acknowledge the International Research Network Hetero-elements and Coordination Chemistry:from Concepts to Applications(HC3A)and Spanish Network Materiales Supramoleculares Funcionales(RED2018-102331-T)This article is based on work from COST Actions CA 17140“Cancer Nanomedicine from the Bench to the Bedside”and CA18202-NECTAR supported by COST(European Cooperation in Science and Technology)SAXS experiments were performed at the NCD-BL11 beamline of the ALBA Synchrotron Light Facility in collaboration with the ALBA staff.
文摘The synthesis of two gold(I)complexes containing a pyridyl ligand with a polyethyleneglycol pendant arm at one position and a chromophore(aniline or coumarin)at the second coordination position is herein reported.These compounds have been observed to aggregate in acetonitrile/water mixtures and the results have been compared with two other gold(I)compounds previously synthesized by our group that contain a water soluble phosphane instead of the pyridyl ligand.We observed that the coumarin derivative is much more stable while the aniline analogue decomposes in the presence of small amounts of water.The aggregation of this coumarin gold(I)compound has been deeply studied by DLS,SAXS,optical microscopy and electron microscopy(SEM and cryo-TEM).The calculation of the crystal packing parameter confirms a vesicle-type assembly.In order to obtain more detailed information about the composition of vesicles,the number of molecules involved in the self-assembly process has been determined(Nagg=82).DFT calculations support these data,determining a size of around 90Åfor the vesicles,which may form coacervates to yield the larger structures observed under a microscope.
文摘Cloud microphysical data observed with PMS probes have been combined with radar and other in-situ data collected by a NOAA P-3 aircraft that flew through the stratiform and transition regions of a mesoscale convective complex(MCC).The combined data have been analyzed with respect to the mescscale structure of the storm systems.The characteristics of ice particles in the transition and stratiform regions were quite differeat.The ice particle concentrations in the transition region were about 4 to 6 times that found in the stratiform region,and the size of ice particles in the stratiform region was about twice that in the transition region.The relatively lower radar reflectivity in the transition region is a result of smaller particle sizes.The main precipitation particle growth mechanisms are riming and aggregation in the transition region ard the aggregation process predominates in the stratiform region referred from the microphysical structures.The ag- gregation starts in the upper,colder levls but becomes more efficient as the particles approach the melting layer.
