An index model for measuring microblog users' influence

Purpose: The paper aims to build an index model for measuring microblog users' influence by taking microbloggers of Sina Weibo as a research sample.Design/methodology/approach: Our user influence index model emphasizes link analysis and user activities in the microblogging network. We conduct experiments to investigate the performance of our model by using data crawled from Sina Weibo.Findings: User influence is correlated to the attention that a user has received from his/her audience,the user's activities and his/her tweets' influence. Experimental results show that our model can reflect microbloggers' influence in a more reasonable way.Research limitations: More factors need to be considered to identify different influential users at different time periods.Practical implications: The results of the study provide us with insights both into the way to measure microblog users' influence and to rank users based on their influence.Originality/value: By combining link analysis and user activities,this index model can reduce the impact of dummy follower accounts on user influence,reflecting a user's real influence in the microblog system.

High-Precision Colorimetric Sensing by Dynamic Tracking of Solvent Diffusion in Hollow-Sphere Photonic Crystals

Expensive instruments and complicated data processing are often required to discriminate solvents with similar structures and properties.Colorimetric sensors with high selectivity,low cost,and good portability are highly desirable to simplify such detection tasks.Herein,we report the fabrication of a photonic crystal sensor based on the self-assembled resorcinol formaldehyde(RF)hollow spheres to realize colorimetric sensing of polar solvents,including homologs and isomers based on the saturated diffusion time.The diffusion of solvent molecules through the photonic crystal film exhibits a unique three-step diffusion profile accompanied by a dynamic color change,as determined by the physicochemical properties of the solvent molecules and their interactions with the polymer shells,making it possible to accurately identify the solvent type based on the dynamic reflection spectra or visual perception.With its superior selectivity and sensitivity,this single-component colorimetric sensor represents a straightforward tool for convenient solvent detection and identification.

基于丝网印刷和光固化油墨制备具有角度变色效应的光子晶体防伪图案

具有角度变色效应的光子晶体图案是一种新型防伪材料.虽然该材料的制备方法早有报道,但鲜有研究工作聚焦于发展低成本、规模化、高效可控的制备技术与工艺.本论文发展了一种结合丝网印刷和光固化过程的新制备方法,以SiO_(2)胶粒/单体为油墨,通过丝印在基材表面构筑图案,并利用紫外光固化最终形成光子晶体图案.通过综合评估光子晶体油墨的固化速度、所制墨迹的角度变色能力、结构色分布均匀性、机械及化学稳定性,从“丙烯酸酯型”、“丙烯酰胺型”、“烯烃型”活性单体中筛选出适于制造光子晶体油墨的单体主料和辅料.此外,通过系统研究丝印模板目数对涂层厚度和印刷分辨率的影响,确定了实现最优结构色强度和图案精度的制备条件.最后,论文提出几种光子晶体防伪图案的设计方案,可实现单色图案随角度变色、双色图案特定角度单色化、层叠图案交替显现等动态视觉效果.

Pt_(1)/Ni_(6)Co_(1)layered double hydroxides/N-doped graphene for electrochemical non-enzymatic glucose sensing by synergistic enhancement of single atoms and doping

The development of novel single-atom catalysts is important for highly efficient electrochemical catalysis and sensing.In this work,a novel Pt single atoms(SAs)supported on Ni_(6)Co_(1)layered double hydroxides/nitrogen-doped graphene(Pt_(1)/Ni_(6)Co_(1)LDHs/NG)was constructed for electrochemical enzyme-free catalysis and sensing towards glucose.The loading of Pt single atoms increases with doping of Co atoms that generate more anchoring sites for Pt SAs.The resulting Pt_(1)/Ni_(6)Co_(1)LDHs/NG exhibits low oxidative potential of 0.440 V with high sensitivity of 273.78μA·mM^(−1)·cm^(−2)toward glucose,which are 85 mV lower and 15 times higher than those of Ni(OH)_(2),respectively.Pt_(1)/Ni_(6)Co_(1)LDHs/NG also shows excellent selectivity and great stability during 5-week testing.Theoretical and experimental results show that the boosted performance of Pt_(1)/Ni_(6)Co_(1)LDHs/NG originates from its stronger binding energy with glucose and the synergistic effect of Pt SAs,Co doping,and NG.This work provides a general strategy of designing highly active SACs for extending their application in electrochemical sensing.

Enhancement of CO_(2)photoreduction efficiency by supporting blue TiO_(2)with photonic crystal substrate

The catalytic performance of TiO_(2)in photoreduction of CO_(2)is limited by its weak absorption in the visible range.In this work,a photonic crystal supported blue TiO_(2)photocatalyst(BTPC)was prepared to demonstrate a 5-6 times higher activity and improved CH_(4)selectivity compared to the BT catalysts deposited on quartz plate.By investigating the influence of the reflection intensity and wavelength of PC support,the superior catalytic performance was found to be originated from the enhanced light absorption of BT and the increased surface electron density brought by the PC support.Based on the study of BT loading on support,multilayer BTPC catalyst was designed to take the most advantage of the transmitted light and achieve a higher conversion of CO_(2)in the unit area of irradiation.

Quantitative mechanisms behind the high strength and electrical conductivity of Cu-Te alloy manufactured by continuous extrusion

The microstructure,mechanical performance,and electrical conductivity of Cu-Te alloy fabricated by continuous extrusion were quantitatively investigated.The results demonstrate that the grain size of the Cu-Te alloy is refined significantly by incomplete dynamic recrystallization.The Cu2Te phase stimulates recrystallization and inhibits subgrain growth.After extrusion,the tensile strength increases from217.8±4.8 MPa to 242.5±3.7 MPa,the yield strength increases from 65.1±3.5 MPa to 104.3±3.8 MPa,and the yield to tensile strength ratio is improved from 0.293±0.015 to 0.43±.0.091,while the electrical conductivity of room temperature decreases from 95.8±0.38%International Annealed Cu Standard(IACS)to 94.0%±0.32%IACS.The quantitative analysis shows that the increment caused by dislocation strengthening and boundary strengthening account for 84.6%of the yield strength of the extruded Cu-Te alloy and the electrical resistivity induced by grain boundaries and dislocations accounts for 1.6%of the electrical resistivity of the extruded Cu-Te alloy.Dislocations and boundaries contribute greatly to the increase of yield strength,but less to the increase of electrical resistivity.