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Large-scale highly ordered periodic Au nano-discs/graphene and graphene/Au nanoholes plasmonic substrates for surface-enhanced Raman scattering

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Nano Research 2019年第11期12卷 2788-2795页

作者： yansheng liu Feng Luo IMDEA Nanoscience Faraday 9Ciudad Unriversitaria de CantoblancoMadrid 28049Spain

In this paper,the study of using masks to directly generate large area,highly ordered and periodical nanostructure has been *** Au nano-discs(NDs)arrays have been fabricated on top of graphene by using holey SigN4 mask which is directly fixed on top of graphene and Au metal is deposited through the holes in mask by thermal evaporation method under vacuum *** fabrication method provides an easy,fast and cost efficiency way to generate periodical ***,Au nanoholes(NHs)structure has been studied by using holey SigN4 as a *** surface-enhanced Raman scattering(SERS)sensitvities of periodical Au NDs/graphene and graphene/Au NHs hybrid structures have been systematically *** internal mechanisms could be explained by chemical mechanism effect of graphene and electromagnetic mechanism effect of metallic *** enhancement factors have been systematically investigated by varying the diameter and the thickness of Au discs and Au *** mappings of Au NDs with 2.5 um diameter ilustrate that the larger SERS enhancements exist in the rim of NDs which has good agreement with the electric field simulation *** SERE enhancement factors of fluorescein obtained from Au NDs/graphene substrates shows an improvement factor of 500%in comparison of graphene *** calculated SERS enhancement factors of graphene/Au NHs achieve 1,200%in comparison of graphene/planar Au film substrate.

关键词： graphene surface-enhanced Raman scattring(SERS) Au nano-discs(NDs) Au nanoholes(NHs) periodic

Prediction of Density and Refractive Index of Lubricating Oils during Secondary Solvent Extraction Process by Furfural

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China Petroleum Processing & Petrochemical Technology 2021年第3期23卷 127-136页

作者： Xu Xiaoling liu yansheng State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)at KaramayKaramay Xinjiang 834000 State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)Beijing 102200

To meet the requirements for high aromatic content and low polycyclic aromatic(PCA)concentration,eco-friendly aromatic-rich rubber extender oils are usually produced by two-stage solvent extraction processes with *** the different properties of rubber processing oils,density and refractive index are some of the most important properties related to their final *** types of methods,including a pseudo-component approach by using mixing rules and several correlations,were used for calculation of density and refractive index at 20℃ of paraffinic furfural-extract oils and their secondary *** indicated that similar accuracy was obtained for predicting the density and the refractive index of furfural+furfural-extract paraffinic oil ***,the quadratic correlation presents its advantage over the pseudo-component approach when the composition of oils is not ***,the quadratic correlation was also used for naphthenic lubricating oils during two-stage solvent extraction *** predictions showed much larger discrepancies with respect to experimental values than those of paraffinic lubricating oils,which indicated that the quadratic correlation was more suitable for paraffinic oils with a CN value of below 37%.

关键词： density refractive index pseudo-components paraffinic furfural-extract oils naphthenic lubricating oils solvent extraction

Amplification of terahertz/infrared field at the nodes of Ranvier for myelinated nerve

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Science China(Physics,Mechanics & Astronomy) 2020年第7期63卷 58-62页

作者： yansheng liu KaiJie Wu ChunLiang liu GangQiang Cui Chao Chang GuoZhi liu Key Laboratory of Physical Electronics and Devices of the Ministry of Education Xi’an Jiaotong UniversityXi'an 710049.China Innovation Laboratory of Terahertz Biophysics National Innovation Institute of Defense TechnologyBejig 100071China Northwest Institute of Nuclear Technology Xi'an 710024China

The myelination of axons was the last major evolution in the vertebrate nervous *** promotes the speed of action potential by two orders,and modulates the conduction of neurons,important for learning new ***,the intrinsic mechanism for high-speed information propagation in myelin in the nervous systems is still *** propose that myelinated nerve fibres serve as dielectric waveguides for the high-frequency electromagnetic information in a certain mid-infrared to terahertz spectral *** on the structure characteristics of myelinated nerve composed of periodic nodes of Ranvier and myelin sheath,the energy for the signal propagation is supplied and amplified when crossing the nodes of Ranvier via a periodic *** this work,we exploit the quasi-quantum model of amplification for neural terahertz/infrared information at the nodes of Ranvier,and prove the existence of biomolecular ensemble for three-energy-level amplification,revealing the essential mechanism of high-speed electromagnetic information transmitting in myelinated nerves.

关键词： terahertz/infrared field myelin nodes of Ranvier quasi-quantum model

Experiments and simulations of gas-solid flow in an airlift loop reactor

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Particuology 2011年第2期9卷 130-138页

作者： Chaoyu Yan Chunxi Lu Yiping Fan Rui Cao yansheng liu State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China

The hydrodynamics in a gas-solid airlift loop reactor was investigated systematically using experimental measurements and CFD simulation. In the experiments, the time averaged parameters, such as solid frac- tion and particle velocity, were measured by optical fiber probe. In the simulation, the modified Gidaspow drag model accounting for the interparticles clustering was incorporated into the Eulerian-Eulerian CFD model with particulate-phase kinetic theory. Predicted values of solid fraction and particle velocity were compared with experimental results, validating the drag model and the simulation. The results show that the profiles of particle velocity and solid fraction are uniform in annulus. However, the core-annulus structure appears in other three regions （draft tube region, bottom region and particle diffluence region）, which presents the similar heterogeneous feature of aggregative fluidization usually occurred in nor- mal fiuidized beds. Simulated profiles of particle residence time distribution indicate that the airlift loop reactor should be characterized by near perfect mixing.

关键词： Airlift loop FeactoFHydrodynamicsGas-solid two phases flowCFDDrag force model

A study of plasmon-driven catalytic 4-NBT to DMAB in the dry film by using spatial Raman mapping spectroscopy

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Nano Research 2022年第7期15卷 6062-6066页

作者： yansheng liu Junpeng Deng Zhicheng Jin Tianxing liu Jin Zhou Feng Luo Guofu Wang School of Microelectronics and Materials Engineering Guangxi University of Science and TechnologyLiuzhou 545006China Department of NanoEngineering University of California San DiegoLa JollaCA 92093USA Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsSchool of Materials Science and Engineering&National Institute for Advanced MaterialsNankai UniversityTianjin 300350China

Plasmon-driven catalytic reaction(PDCR)as a part of photocatalysis has attracted immense *** to the collective oscillation of free electrons at the surface of metallic nanostructures,the charge distributions store energy from the incident light that could transfer energy to molecules that promote *** an environment-friendly and green photocatalysis process,PDCR illustrates a brilliant *** this study,the PDCR efficiency of photo-reducing 4-nitro-benzenthiol(4-NBT)dry film to p,p'-dimercaptoazobenzene(DMAB)in ambient conditions has been studied by using Ag nanodiscs(NDs)and Ag nanoparticles(NPs)as *** distribution of catalytic efficiency of 4-NBT to DMAB using an individual Ag ND catalyst has been illustrated using spatial Raman *** result is direct evidence that the PDCR efficiency has a positive correlation with plasmon-induced electromagnetic field ***,time-dependent surface-enhanced Raman scattering(SERS)experiments reveal that the PDCR of 4-NBT to DMAB is *** discovery in this research will aid to improve the PDCR performance and modulate the catalysis reaction for a high reduction of 4-NBT in industrial.

关键词： plasmon photocatalysis 4-nitro-benzenthiol(4-NBT) surface-enheanced Raman scattering(SERS)

A criterion for flow mechanisms through vertical sharp-edged orifice and model for the orifice discharge coefficient

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Petroleum Science 2011年第1期8卷 108-113页

作者： Cao Rui liu yansheng Yan Chaoyu State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China

According to the experimental data of the orifice discharge coefficient for the flow through a vertical sharp-edged orifice obtained in the previous study of this work,a theoretical criterion for flow mechanisms of small orifice（***-walled orifice and nozzle） and large orifice（***-walled orifice） was proposed based on the ratio of orifice diameter to plate *** can help explain the dissipation of the mechanical energy loss in the flow process for the two flow mechanisms under different operating *** main parameters such as orifice diameter,plate thickness and liquid head were correlated,and a semi-empirical model for orifice coefficient and an empirical model with high precision at the stable region were developed.

关键词： Orifice discharge coefficient theoretical criterion model ratio of orifice diameter to plate thickness Reynolds number liquid head

Simulation of Solvent Extraction for Naphthenic Lubricating Base Oils

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China Petroleum Processing & Petrochemical Technology 2023年第3期25卷 153-164页

作者： Xu Xiaoling Wang Tianqi Tian Qingmei liu yansheng State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)at KaramayKaramay Xinjiang 834000China State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102200China

Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in light of itshigher selectivity, to obtain extracts with a high aromatic content for naphthenic lubricating base oils. We systematicallyinvestigated effects of the solvent-to-oil (S/O) ratio and extraction temperature on the yield of the extract, efficiency ofaromatic removal, and composition of the extracts and raffinates. The results showed that the aromatic content of extractsfor naphthenic oils could reach a high value of about 80%. The solvent maintained a high selectivity for aromatics fornaphthenic oils even under a high S/O ratio and a high extraction temperature. Moreover, the efficiency of aromatic removalfor naphthenic lubricating base oils could be enhanced by increasing either the S/O ratio or the extraction temperature,although these measures had limited effects in practice. Following this, we used the non-random two-liquid (NRTL) modelbased on the pseudo-component approach to simulate the liquid-liquid equilibrium of the system of DMSO + naphtheniclubricating base oils, and determined the parameters of binary interaction through regression based on the data on phaseequilibrium. The modeling results showed that the predicted yield, content of the solvent, and composition of the raffinatesand extracts were in good agreement with those obtained in the experiments. This validates the reliability of the model usedto represent the DMSO + naphthenic lubricating base oil system. Both the experimental data and the method of simulationreported here can help optimize the extraction of naphthenic lubricating base oils, and provide a better understanding of thecorresponding process.

关键词： solvent extraction naphthenic lubricating base oils liquid-liquid equilibrium thermodynamic model DMSO

Separation of ionic liquids from dilute aqueous solutions using the method based on CO_2 hydrates

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Journal of Natural Gas Chemistry 2010年第1期19卷 81-85页

作者： Xiaoming Peng Yufeng Hu yansheng liu Chuanwei Jin Huaijing Lin State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China School of Chemical Engineering Sichuan University Chengdu 610065 Sichuan China

Ionic liquids （ILs） have been regarded as the potential novel solvents for improved analytical- and process-scale separation *** development of methods for the recovery of ILs from aqueous solutions to escape contamination and recycle samples will ultimately govern the viability of ILs in the future industrial applications. Therefore, in this paper a new method for separation of ILs from their dilute aqueous solutions and simultaneously purification of water was proposed on the basis of the CO2 hydrate formation. For illustration, the dilute aqueous solutions with concentrations of ILs ranging from 2× 10^-3 mol% to 2×10^-1 mol% were concentrated. The results show that the separation efficiency is very impressive and that the new method is applicable to aqueous solutions of both hydrophobic and hydrophilic ILs. Compared to the literature separation method based on the supercritical CO2, the new method is applicable to lower concentrations, and more importantly, its operation condition is mild.

关键词： ionic liquids separation CO2 hydrates aqueous solution

Synchronization of switched Boolean networks with impulsive effects

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International Journal of Biomathematics 2018年第6期11卷 93-110页

作者： Xiaojing Xu yansheng liu Haitao Li Fuad E. Alsaadi School of Mathematics and Statistics Shandong Normal University Jinan 250014 P. R. China Department of Electrical and Computer Engineering Faculty of Engineering King Abdulaziz University Jeddah 21589 Saudi Arabia

This paper studies the state/output synchronization of switched Boolean networks （SBNs） with impulsive effects via the algebraic state space representation （ASSR） approach. First, an algebraic form is established for SBNs with impulsive effects via ASSR. Second, based on the algebraic form, some necessary and sufficient conditions are presented for the state/output synchronization of SBNs with impulsive effects under arbitrary switching signals. Third, two special kinds of switching signals, that is, free switching signal and feedback switching signal, are considered for the state synchroniza-tion of SBNs with impulsive effects. Finally, two illustrative examples are worked out to show the effectiveness of the obtained results.

关键词： Switched Boolean network impulsive effects synchronization algebraic state space representation.