The adsorption of isomaltotriose from aqueous solution on Ca2+ resin was investigated. The adsorption isotherm and the rate curve were determined. The pseudo-first-order model, pseudo-second-order model and the intrap...The adsorption of isomaltotriose from aqueous solution on Ca2+ resin was investigated. The adsorption isotherm and the rate curve were determined. The pseudo-first-order model, pseudo-second-order model and the intraparticle diffusion model were used to predict the rate constants of adsorption. The activation energy of adsorption has been also evaluated using the pseudo-second-order rate constants. The results showed that the adsorption of isomaltotriose onto Ca2+ resin is an exothermically activated process. The adsorption isotherm can be described by Langmuir equation. The pseudo-second-order model can fit well to the adsorption rate curve of isomaltotriose onto Ca2+ resin. It suggests that the adsorption of isomaltotriose onto Ca2+ resin involve chemical adsorption.展开更多
We introduce a kind of generalized Wigner operator,whose normally ordered form can lead to the bivariatenormal distribution in p-q phase space.While this bivariate normal distribution corresponds to the pure vacuum st...We introduce a kind of generalized Wigner operator,whose normally ordered form can lead to the bivariatenormal distribution in p-q phase space.While this bivariate normal distribution corresponds to the pure vacuum state inthe generalized Wigner function phase space,it corresponds to a mixed state in the usual Wigner function phase space.展开更多
Recently Rafiee et al. experimentally demonstrated the wetting transparency of graphene, but there is still no comprehensive theoretical explanation of this physical phenomenon. Since surface free energy is one of the...Recently Rafiee et al. experimentally demonstrated the wetting transparency of graphene, but there is still no comprehensive theoretical explanation of this physical phenomenon. Since surface free energy is one of the most important parameters characterizing material surfaces and is closely related to the wetting behavior, the surface free energy of suspended monolayer graphene is analyzed based on its microscopic formation mechanism. The surface free energy of suspended monolayer graphene is shown to be zero, which suggests its super-hydrophobicity. Neumann's equation of state is applied to further illustrate the contact angle, θ, of any liquid droplet on a suspended monolayer graphene is 180 o. This indicates that the van der Waals(vd W) interactions between the monolayer graphene and any liquid droplet are negligible; thus the monolayer graphene coatings exhibit wetting transparency to the underlying substrate. Moreover, molecular dynamics(MD) simulations are employed to further confirm the wetting transparency of graphene in comparison with experimental results of Rafiee et al. These findings provide a fundamental picture of wetting on ideal single atomic layer materials, including monolayer graphene. Thus, these results provide a useful guide for the design and manufacture of biomaterials, medical instruments, and renewable energy devices with monolayer graphene layers.展开更多
Magnetic topological quantum materials(TQMs) provide a fertile ground for the emergence of fascinating topological magneto-electric effects. Recently, the discovery of intrinsic antiferromagnetic(AFM) topological insu...Magnetic topological quantum materials(TQMs) provide a fertile ground for the emergence of fascinating topological magneto-electric effects. Recently, the discovery of intrinsic antiferromagnetic(AFM) topological insulator MnBi_(2)Te_(4) that could realize quantized anomalous Hall effect and axion insulator phase ignited intensive study on this family of TQM compounds. Here, we investigated the AFM compound Mn Bi4 Te7 where Bi_(2)Te_(3) and MnBi_(2)Te_(4) layers alternate to form a superlattice. Using spatial-and angleresolved photoemission spectroscopy, we identified ubiquitous(albeit termination dependent) topological electronic structures from both Bi_(2)Te_(3) and MnBi_(2)Te_(4) terminations. Unexpectedly, while the bulk bands show strong temperature dependence correlated with the AFM transition, the topological surface states with a diminishing gap show negligible temperature dependence across the AFM transition.Together with the results of its sister compound MnBi_(2)Te_(4), we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.展开更多
基金Natural Science Foundation of Guangdong Province (5300563)
文摘The adsorption of isomaltotriose from aqueous solution on Ca2+ resin was investigated. The adsorption isotherm and the rate curve were determined. The pseudo-first-order model, pseudo-second-order model and the intraparticle diffusion model were used to predict the rate constants of adsorption. The activation energy of adsorption has been also evaluated using the pseudo-second-order rate constants. The results showed that the adsorption of isomaltotriose onto Ca2+ resin is an exothermically activated process. The adsorption isotherm can be described by Langmuir equation. The pseudo-second-order model can fit well to the adsorption rate curve of isomaltotriose onto Ca2+ resin. It suggests that the adsorption of isomaltotriose onto Ca2+ resin involve chemical adsorption.
基金National Natural Science Foundation of China under Grant Nos.10775097 and 10874174
文摘We introduce a kind of generalized Wigner operator,whose normally ordered form can lead to the bivariatenormal distribution in p-q phase space.While this bivariate normal distribution corresponds to the pure vacuum state inthe generalized Wigner function phase space,it corresponds to a mixed state in the usual Wigner function phase space.
基金the National Natural Science Foundation of China (Grant No. 51636002 and No. 51706118)the National Postdoctoral Program for Innovative Talents of China (Grant No. BX201600081)China Postdoctoral Science Foundation (Grant No. 2017M610889)
文摘Recently Rafiee et al. experimentally demonstrated the wetting transparency of graphene, but there is still no comprehensive theoretical explanation of this physical phenomenon. Since surface free energy is one of the most important parameters characterizing material surfaces and is closely related to the wetting behavior, the surface free energy of suspended monolayer graphene is analyzed based on its microscopic formation mechanism. The surface free energy of suspended monolayer graphene is shown to be zero, which suggests its super-hydrophobicity. Neumann's equation of state is applied to further illustrate the contact angle, θ, of any liquid droplet on a suspended monolayer graphene is 180 o. This indicates that the van der Waals(vd W) interactions between the monolayer graphene and any liquid droplet are negligible; thus the monolayer graphene coatings exhibit wetting transparency to the underlying substrate. Moreover, molecular dynamics(MD) simulations are employed to further confirm the wetting transparency of graphene in comparison with experimental results of Rafiee et al. These findings provide a fundamental picture of wetting on ideal single atomic layer materials, including monolayer graphene. Thus, these results provide a useful guide for the design and manufacture of biomaterials, medical instruments, and renewable energy devices with monolayer graphene layers.
基金supported by the National Key Research and Development Program of China (2017YFA0305400, 2017YFA0304600, 2018YFA0307100, and 2018YFA0305603)the National Natural Science Foundation of China (11774190, 11674229, 11634009, 11774427, 51788104, and 11874035)+1 种基金EPSRC Platform Grant (EP/M020517/1)the support from the Shanghai Pujiang Program (17PJ1406200)。
文摘Magnetic topological quantum materials(TQMs) provide a fertile ground for the emergence of fascinating topological magneto-electric effects. Recently, the discovery of intrinsic antiferromagnetic(AFM) topological insulator MnBi_(2)Te_(4) that could realize quantized anomalous Hall effect and axion insulator phase ignited intensive study on this family of TQM compounds. Here, we investigated the AFM compound Mn Bi4 Te7 where Bi_(2)Te_(3) and MnBi_(2)Te_(4) layers alternate to form a superlattice. Using spatial-and angleresolved photoemission spectroscopy, we identified ubiquitous(albeit termination dependent) topological electronic structures from both Bi_(2)Te_(3) and MnBi_(2)Te_(4) terminations. Unexpectedly, while the bulk bands show strong temperature dependence correlated with the AFM transition, the topological surface states with a diminishing gap show negligible temperature dependence across the AFM transition.Together with the results of its sister compound MnBi_(2)Te_(4), we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.
