Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth'...Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth's surface environments.The results reveal that,in comparison to aqueous H_4SiO_4,heavy Si isotopes will be significantly enriched in secondary silicate minerals.On the contrary,quadra-coordinated organosilicon complexes are enriched in light silicon isotope relative to the solution.The extent of ^(28)Si-enrichment in hyper-coordinated organosilicon complexes was found to be the largest.In addition,the large kinetic isotope effect associated with the polymerization of monosilicic acid and dimer was calculated,and the results support the previous statement that highly ^(28)Sienrichment in the formation of amorphous quartz precursor contributes to the discrepancy between theoretical calculations and field observations.With the equilibrium Si isotope fractionation factors provided here,Si isotope distributions in many of Earth's surface systems can be explained.For example,the change of bulk soil δ^(30)Si can be predicted as a concave pattern with respect to the weathering degree,with the minimum value where allophane completely dissolves and the total amount of sesquioxides and poorly crystalline minerals reaches their maximum.When,under equilibrium conditions,the well-crystallized clays start to precipitate from the pore solutions,the bulk soil δ^(30)Si will increase again and reach a constant value.Similarly,the precipitation of crystalline smectite and the dissolution of poorly crystalline kaolinite may explain the δ^(30)Si variations in the ground water profile.The equilibrium Si isotope fractionations among the quadracoordinated organosilicon complexes and the H_4SiO_4solution may also shed light on the Si isotope distributions in the Si-accumulating plants.展开更多
This paper reports that the YBa2Cu3-xZnxO7-δ （x = 0-0.4） samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results ...This paper reports that the YBa2Cu3-xZnxO7-δ （x = 0-0.4） samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results of simulated calculations, positron experiments and variations of oxygen content support the existence of cluster effect. Moreover, it is concluded that the cluster effect is an important factor on suppression of high-Tc cuprate superconductivity and the Tc does not depend on the density of valence electron directly.展开更多
By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L...By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.展开更多
Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was a...Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was applied as a new simplified strategy to both recognize and inhibit a single bacteria species of Staphylococcus aureus(S. aureus) simultaneously. The probes are composed of peptides and Au clusters. Moreover, the peptides specifically target S. aureus cells and the Au clusters provide fluorescent imaging and have an antibacterial effect. These new probes enable the simultaneous specific detection and effective destruction S. aureus cells in situ.展开更多
The principle of increasing entropy （PIE） is commonly considered as a universal physical law tbr natural systems. It also means that a non-equilibrium steady state （NESS） must not appear in any isolated natural sy...The principle of increasing entropy （PIE） is commonly considered as a universal physical law tbr natural systems. It also means that a non-equilibrium steady state （NESS） must not appear in any isolated natural systems. Here we experimentally investigate an isolated human social system with a clustering effect. We report that the PIE cannot always hold, and that NESSs can come to appear. Our study highlights the role of human adaptability in the PIE, and makes it possible to study human social systems by using some laws originating from traditional physics.展开更多
A cluster-based drag model is proposed for the gas-solid circulating fluidized bed(CFB)riser by including the cluster information collected from image processing and wavelet analysis into the calculation of system dra...A cluster-based drag model is proposed for the gas-solid circulating fluidized bed(CFB)riser by including the cluster information collected from image processing and wavelet analysis into the calculation of system drag.The performance of the proposed drag model is compared with some commonly used drag models.A good agreement with the experimental data is achieved by the proposed cluster-based drag model.Error analysis of the proposed cluster-based drag model based on the local distributions of solids holdup and particle velocity is conducted.The clustering phenomenon in the low-density and high-density CFB risers and the effect of the cluster size on the simulation accuracy are also numerically studied by the proposed drag model.展开更多
Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloy...Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single-crystal superalloys; thus, the content of Re is considered as one of the characteristics in different-generation single-crystal superalloys. Owing to the fundamental importance of rhenium to nickel-based single-crystal superalloys, much progress has been made on understanding of the effect of rhenium in the single-crystal superalloys. While the effect of Re doping on the nickelbased superalloys is well documented, the origins of the socalled rhenium effect are still under debate. In this paper,the effect of Re doping on the single-crystal superalloys and progress in understanding the rhenium effect are reviewed. The characteristics of the d-states occupancy in the electronic structure of Re make it the slowest diffusion elements in the single-crystal superalloys, which is undoubtedly responsible for the rhenium effect, while the postulates of Re cluster and the enrichment of Re at the c/c0 interface are still under debate, and the synergistic action of Re with other alloying elements should be further studied.Additionally, the interaction of Re with interfacial dislocations seems to be a promising explanation for the rhenium effect. Finally, the addition of Ru could help suppress topologically close-packed（TCP） phase formation and strengthen the Re doping single-crystal superalloys.Understanding the mechanism of rhenium effect will be beneficial for the effective utilization of Re and the design of low-cost single-crystal superalloys.展开更多
In an effort to find highly efficient ligands for hepatic asialoglycoprotein receptor （ASGPR）, four cluster galactosides with different scaffolds were synthesized in this paper. The affinity of these compounds for A...In an effort to find highly efficient ligands for hepatic asialoglycoprotein receptor （ASGPR）, four cluster galactosides with different scaffolds were synthesized in this paper. The affinity of these compounds for ASGPR was analyzed by binding study in vitro. The results showed that trivalent cluster galactosides behaved better than divalent analogues and the cluster galactosides with aryl groups on their scaffolds presented better binding affinity than those with aliphatic chain scaffolds.展开更多
基金the funding support from the 973 Program(2014CB440904)CAS/SAFEA International Partnership Program for Creative Research Teams(Intraplate Mineralization Research Team,KZZD-EW-TZ-20)Chinese NSF projects(41173023,41225012,41490635,41530210)
文摘Several important equilibrium Si isotope fractionation factors among minerals,organic molecules and the H_4SiO_4 solution are complemented to facilitate the explanation of the distributions of Si isotopes in Earth's surface environments.The results reveal that,in comparison to aqueous H_4SiO_4,heavy Si isotopes will be significantly enriched in secondary silicate minerals.On the contrary,quadra-coordinated organosilicon complexes are enriched in light silicon isotope relative to the solution.The extent of ^(28)Si-enrichment in hyper-coordinated organosilicon complexes was found to be the largest.In addition,the large kinetic isotope effect associated with the polymerization of monosilicic acid and dimer was calculated,and the results support the previous statement that highly ^(28)Sienrichment in the formation of amorphous quartz precursor contributes to the discrepancy between theoretical calculations and field observations.With the equilibrium Si isotope fractionation factors provided here,Si isotope distributions in many of Earth's surface systems can be explained.For example,the change of bulk soil δ^(30)Si can be predicted as a concave pattern with respect to the weathering degree,with the minimum value where allophane completely dissolves and the total amount of sesquioxides and poorly crystalline minerals reaches their maximum.When,under equilibrium conditions,the well-crystallized clays start to precipitate from the pore solutions,the bulk soil δ^(30)Si will increase again and reach a constant value.Similarly,the precipitation of crystalline smectite and the dissolution of poorly crystalline kaolinite may explain the δ^(30)Si variations in the ground water profile.The equilibrium Si isotope fractionations among the quadracoordinated organosilicon complexes and the H_4SiO_4solution may also shed light on the Si isotope distributions in the Si-accumulating plants.
基金supported by the National Natural Science Foundation of China (Grant No 10647145)The Basic Science Foundation of Henan Educational Bureau of China
文摘This paper reports that the YBa2Cu3-xZnxO7-δ （x = 0-0.4） samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results of simulated calculations, positron experiments and variations of oxygen content support the existence of cluster effect. Moreover, it is concluded that the cluster effect is an important factor on suppression of high-Tc cuprate superconductivity and the Tc does not depend on the density of valence electron directly.
文摘By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.
基金supported by the National Natural Science Foundation of China(21727817,21390414,21425522,51571185)Beijing Science and Technology Commission Special Project for Frontier Technology in Life Sciences(Z171100000417008)
文摘Increasingly serious microbial infections call for the development of new simpler methods for the precise diagnosis and specific inhibition of such pathogens. In this work, a peptide mineralized Au cluster probe was applied as a new simplified strategy to both recognize and inhibit a single bacteria species of Staphylococcus aureus(S. aureus) simultaneously. The probes are composed of peptides and Au clusters. Moreover, the peptides specifically target S. aureus cells and the Au clusters provide fluorescent imaging and have an antibacterial effect. These new probes enable the simultaneous specific detection and effective destruction S. aureus cells in situ.
文摘The principle of increasing entropy （PIE） is commonly considered as a universal physical law tbr natural systems. It also means that a non-equilibrium steady state （NESS） must not appear in any isolated natural systems. Here we experimentally investigate an isolated human social system with a clustering effect. We report that the PIE cannot always hold, and that NESSs can come to appear. Our study highlights the role of human adaptability in the PIE, and makes it possible to study human social systems by using some laws originating from traditional physics.
文摘A cluster-based drag model is proposed for the gas-solid circulating fluidized bed(CFB)riser by including the cluster information collected from image processing and wavelet analysis into the calculation of system drag.The performance of the proposed drag model is compared with some commonly used drag models.A good agreement with the experimental data is achieved by the proposed cluster-based drag model.Error analysis of the proposed cluster-based drag model based on the local distributions of solids holdup and particle velocity is conducted.The clustering phenomenon in the low-density and high-density CFB risers and the effect of the cluster size on the simulation accuracy are also numerically studied by the proposed drag model.
基金financially supported by the National Basic Research Program of China(No.2009CB623701)the National Natural Science Foundation of China(Nos.11374174,50971075 and 51390471)
文摘Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single-crystal superalloys; thus, the content of Re is considered as one of the characteristics in different-generation single-crystal superalloys. Owing to the fundamental importance of rhenium to nickel-based single-crystal superalloys, much progress has been made on understanding of the effect of rhenium in the single-crystal superalloys. While the effect of Re doping on the nickelbased superalloys is well documented, the origins of the socalled rhenium effect are still under debate. In this paper,the effect of Re doping on the single-crystal superalloys and progress in understanding the rhenium effect are reviewed. The characteristics of the d-states occupancy in the electronic structure of Re make it the slowest diffusion elements in the single-crystal superalloys, which is undoubtedly responsible for the rhenium effect, while the postulates of Re cluster and the enrichment of Re at the c/c0 interface are still under debate, and the synergistic action of Re with other alloying elements should be further studied.Additionally, the interaction of Re with interfacial dislocations seems to be a promising explanation for the rhenium effect. Finally, the addition of Ru could help suppress topologically close-packed（TCP） phase formation and strengthen the Re doping single-crystal superalloys.Understanding the mechanism of rhenium effect will be beneficial for the effective utilization of Re and the design of low-cost single-crystal superalloys.
基金Project supported by the Program for New Century Excellent Talents in University （No. NCET-04-0649） and the National Natural Science Foundation of China （No. 20475030）.
文摘In an effort to find highly efficient ligands for hepatic asialoglycoprotein receptor （ASGPR）, four cluster galactosides with different scaffolds were synthesized in this paper. The affinity of these compounds for ASGPR was analyzed by binding study in vitro. The results showed that trivalent cluster galactosides behaved better than divalent analogues and the cluster galactosides with aryl groups on their scaffolds presented better binding affinity than those with aliphatic chain scaffolds.
