Chaos in social learning with multiple true states

Most existing social learning models assume that there is only one underlying true state. In this work, we consider a social learning model with multiple true states, in which agents in different groups receive different signal sequences generated by their corresponding underlying true states. Each agent updates his belief by combining his rational self-adjustment based on the external signals he received and the influence of his neighbors according to their communication. We observe chaotic oscillation in the belief evolution, which implies that neither true state could be learnt correctly by calculating the largest Lyapunov exponents and Hurst exponents.     

Preparation of graphene/zeolite composites and the adsorption of pollutants in water

Russian Journal of Applied Chemistry - Based on the advantages of graphene and zeolite, respectively, the graphene/zeolite composites with core-shell structure were synthesized. The features of the...     

Ru掺杂BiOBr空心微球的原位合成及其光催化CO_2还原和有机污染物降解性能研究

采用水热法原位合成了Ru掺杂BiOBr空心微球(Ru/BiOBr)复合光催化剂,并对其进行了XRD、 SEM、 TEM、 EDS、 DRS、 EIS等表征.结果表明,所合成的BiOBr材料是由许多小厚度的交错纳米片自组装而成的,同时Ru纳米颗粒成功负载到BiOBr表面,该复合材料对还原CO_2和降解有机模拟污染物(罗丹明B, RhB)具有良好的光催化性能.当Ru的掺杂量为0.4%时复合材料的光催化活性最佳, 4 h后甲醇产量可达1103μmol/g_(cat),并且60 min内对RhB的降解率达到98%.除此之外,还讨论了复合材料的光催化机理和稳定性.     

Effects of organic modifiers on the size-controlled synthesis of hydroxyapatite nanorods

Size-controlled synthesis of hydroxyapatite nanorods were carried out by chemical precipitation method using polyethylene glycol (MW 600), Tween 20, trisodium citrate, and d-sorbitol as organic modifiers and starting from calcium nitrate, phosphoric acid, and ammonia solution. The influence of the organic modifiers on the sizes of the resultant HAP nanorods was investigated under different synthesis temperatures. It was found that polyethylene glycol was beneficial to the formation of HAP nanorods with a larger aspect ratio (average length/average diameter) at high synthesis temperature, Tween 20 and trisodium citrate favored the formation of small-sized HAP nanorods, and d-sorbitol helped the formation of HAP nanorods with long length at low synthesis temperatures.     

Evolution of TiO2 coating layers on lamellar sericite in the presence of La and the pigmentary properties

TiO₂-coated sericite powders were prepared by the chemical deposition method starting from lamellar sericite and TiCl₄ in the presence or absence of La³⁺ cations. After calcination at 900 °C for 1 h, the resultant TiO₂ nanoparticles on the sericite surfaces existed in anatase phase. The light scattering indexes of the TiO₂-coated lamellar sericite powders were dozens of times higher than that of the naked lamellar sericite powders. The presence of La³⁺ in the deposition solution was beneficial to the formation of the small-sized anatase TiO₂ nanoparticles, resulting in the formation of the dense and uniform island-like TiO₂ coating layers in a large range of the weight ratios of TiO₂ to sericite from 5% to 20%. The TiO₂-coated lamellar sericite powders prepared in the presence of La³⁺ had higher light scattering index than that prepared in the absence of La³⁺. XPS analysis shows that when La³⁺ cations were absent in the reaction solution, TiO₂ coating layers anchored at the sericite surface via the Ti-O-Si and Ti-O-Al bonds. The presence of La³⁺ cations caused the formation of Si-O-La and Al-O-La bonds at the sericite surface and Ti-O-La bond at the surface of TiO₂ coating layers. After coating TiO₂ on the sericite surface, the yellowness of the TiO₂-coated sericite powders obviously increased and the brightness slightly decreased.     

The pasting constructions for effect algebras

The aim of this paper is to present several techniques of constructing a lattice-ordered effect algebra from a given family of lattice-ordered effect algebras, and to study the structure of finite lattice-ordered effect algebras. Firstly, we prove that any finite MV-effect algebra can be obtained by substituting the atoms of some Boolean algebra by linear MV-effect algebras. Then some conditions which can guarantee that the pasting of a family of effect algebras is an effect algebra are provided. At last, we prove that any finite lattice-ordered effect algebra E without atoms of type 2 can be obtained by substituting the atoms of some orthomodular lattice by linear MV-effect algebras. Furthermore, we give a way how to paste a lattice-ordered effect algebra from the family of MV-effect algebras.     

Dearomative [4 + 2] cycloaddition of 3-nitroindoles with ortho-amino Morita−Baylis−Hillman carbonates to forge indole-fused quinolines

A dearomative [4 + 2] cycloaddition of 3-nitroindoles ortho-amino Morita−Baylis−Hillman carbonates was established under mild conditions. This method provides an efficient and practical approach for delivering tetrahydro-5H-indolo[2,3-b]quinolines containing three contiguous stereocenters, two tertiary and one quaternary, in high yield (up to 95%) with excellent diastereoselectivity (all cases >25:1 dr). The potential synthetic applications of this strategy were also highlighted by the scale-up experiment and further synthetic transformation. Moreover, the structure and relative configuration of the cycloadduct was unequivocally confirmed by single-crystal X-ray diffraction.     

Effects of coating parameters on the morphology of SiO2-coated TiO2 and the pigmentary properties

SiO₂-coated TiO₂ powders were prepared by the chemical deposition method starting from rutile TiO₂ and Na₂SiO₃. The SiO₂-coated TiO₂ powders were characterized by X-ray photoelectron spectroscopy, Zeta-potential analysis, Fourier transform infrared spectroscopy, and transmission electron microscopy. The evolution of island-like and uniform coating layers was found to depend upon the ratio of Na₂SiO₃ to TiO₂, reaction temperature, and pH. The whiteness and brightness of the SiO₂-coated TiO₂ powders increased in response to an increase in the SiO₂ loading, but there was a maximum value among the light scattering indexes. The SiO₂-coated TiO₂ powders possessed more negative Zeta potentials than the naked TiO₂. The dispersibility of the SiO₂-coated TiO₂ powders with the continuous and uniform SiO₂ coating layers was higher than that of the naked TiO₂ and the SiO₂-coated TiO₂ powders with the island-like SiO₂ coating layers.     

Synergistic effect of silver seeds and organic modifiers on the morphology evolution mechanism of silver nanoparticles

Triangular, truncated triangular, quadrangular, hexagonal, and net-structured silver nanoplates as well as decahedral silver nanoparticles were manipulatively prepared starting from silver nitrate and silver seeds in the presence of poly(ethylene glycol) (PEG), poly(N-vinyl pyrrolidone) (PVP), and Tween 80 at room temperature, respectively. UV-vis spectroscopy, XRD, HRTEM, SAED, and FTIR were used to illustrate the crystal growth process and to characterize the resultant silver nanoparticles. It was found that the silver seeds and organic modifiers synergistically affected the morphology evolution of the silver nanoparticles. The co-presence of silver seeds and PEG was beneficial to the formation of triangular and truncated triangular silver nanoplates; the silver seeds and PVP favored the formation of polygonal silver nanoplates; the silver seeds and Tween 80 preferred to the formation of net-structured silver plates. The morphology evolution of the resultant silver nanoparticles was correlated with the crystallinity of the silver seeds and the adsorption ability of the organic modifiers on the crystal surfaces.