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Synthesis and Electrochemical Performance of Co3O4/Graphene

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Chemical Research in Chinese Universities 2014年第4期30卷 650-655页

作者： WANG Hongzhi SHI Yulei LI Zixuan ZHANG Weiguo YAO Suwei department of applied Chemistry School oJ Chemical Engineering and Technology Tianjin University Tianjin 300072 P. R. China

Co3O4/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co（NO3）2·6H2O as raw ***3O4 nanoparticles with sizes of around 30-50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron *** properties of Co3O4/graphene composite were tested by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance *** Co3O4/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte *** Co3O4/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system.72％ of capacitance was retained when the current density increased to 3 A/*** Co3O4/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term *** 1000 cycles of charge and discharge,the capacitance is still maintained 87％ at a current density of 1 A/g,indicating that the composite is a oromising alternative electrode material used for supercapacitors.

关键词： Cobalt oxide Graphene Composite Electrochemical preparation Supercapacitor

Hyperbranched Polyurethane Acrylate applied to UV Curable Flame Retardant Coatings

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Chemical Research in Chinese Universities 2001年第3期17卷 331-333页

作者： ZHU Sheng-Wu SHI Wen-Fang State Key Laboratory of Fire Science Department of Applied ChemistryUniversity of Science and Technology of ChinaHefei 230026P.R.China

UV curable hyperbranched prepolymers based on amine-ester, ester-amide and ether-amide started with AB_2-type monomers have been prepared by the authors. A series of work on allyl ether maleate hyperbranched polyesters for UV curing coatings by Hult and his colleagues has been reported. However, the UV cured films from those materials are all flammable when attached to fire without addition of flame retardants.

关键词： Flame retardant Polyurethane acrylate Phosphorus UV curing

A Secure Rotation Invariant LBP Feature Computation in Cloud Environment

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Computers, Materials & Continua 2021年第9期68卷 2979-2993页

作者： Shiqi Wang Mingfang Jiang Jiaohua Qin Hengfu Yang Zhichen Gao College of Computer Science and Information Technology Central South University of Forestry and TechnologyChangsha410004China department of Information Science and Engineering Hunan First Normal UniversityChangsha410205China department of applied Mathematics and Statistics College of Engineering and Applied SciencesStony Brook UniversityNY11794USA

In the era of big data,outsourcing massive data to a remote cloud server is a promising *** storage and computation services can reduce storage costs and computational ***,public cloud storage brings about new privacy and security concerns since the cloud servers can be shared by multiple ***-preserving feature extraction techniques are an effective solution to this *** the Rotation Invariant Local Binary Pattern(RILBP)has been widely used in various image processing fields,we propose a new privacy-preserving outsourcing computation of RILBP over encrypted images in this paper(called PPRILBP).To protect image content,original images are encrypted using block scrambling,pixel circular shift,and pixel diffusion when uploaded to the cloud *** is proved that RILBP features remain unchanged before and after ***,the server can directly extract RILBP features from encrypted *** and experiments confirm that the proposed scheme is secure and effective,and outperforms previous secure LBP feature computing methods.

关键词： Privacy-preserving rotation invariant local binary pattern cloud computing image encryption

Robust Optimal Higher-order-observer-based Dynamic Sliding Mode Control for VTOL Unmanned Aerial Vehicles

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International Journal of Automation and computing 2021年第5期18卷 802-813页

作者： Yashar Mousavi Amin Zarei Arash Mousavi Mohsen Biari department of applied Science School of ComputingEngineering and Built EnvironmentGlasgow Caledonian UniversityGlasgow G4 OBAUK department of Electrical and Computer Engineering University of Sistan and BaluchestanZahedan ***Iran department Electrical Engineering and applied Sciences Paradise Research CenterJahrom ***Iran Faculty of Electrical and Robotic Engineering Shahrood University of TechnologyShahrood ***Iran

This paper investigates the precise trajectory tracking of unmanned aerial vehicles(UAV) capable of vertical take-off and landing(VTOL) subjected to external disturbances. For this reason, a robust higher-order-observer-based dynamic sliding mode controller(HOB-DSMC) is developed and optimized using the fractional-order firefly algorithm(FOFA). In the proposed scheme, the sliding surface is defined as a function of output variables, and the higher-order observer is utilized to estimate the unmeasured variables,which effectively alleviate the undesirable effects of the chattering phenomenon. A neighboring point close to the sliding surface is considered, and as the tracking error approaches this point, the second control is activated to reduce the control input. The stability analysis of the closed-loop system is studied based on Lyapunov stability theorem. For a better study of the proposed scheme, various trajectory tracking tests are provided, where accurate tracking and strong robustness can be simultaneously ensured. Comparative simulation results validate the proposed control strategy′s effectiveness and its superiorities over conventional sliding mode controller(SMC) and integral SMC approaches.

关键词： Unmanned aerial vehicle dynamic sliding mode trajectory tracking fractional firefly algorithm vertical take-off and landing system

Pressure-Induced Shifts of R1 and R2 Lines of YAG：Cr3＋

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Communications in Theoretical Physics 2006年第4期45卷 754-760页

作者： ZHANG Zheng-Jie MA Dong-Ping College of Information Engineering Chengdu University of Technology Chengdu 610059 China department of applied Physics Sichuan University Chengdu 610065 China

By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shifts （PS＇s） and the PS＇s due to electron-phonon interaction （EPI） of R1 line and R2 line of YAG：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of │t^2 2（^3T1）e^4T2〉 and │t^3 2 ^2E〉 bases in the wavefunction of RI level of YAG：Crs＋ and its change with pressure play a key role for the PS of RI line. The behaviors of the ＂pure electronic＂ PS of RI line and the PS of RI line due to EPI are different. It is the combined eEect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG：Cr^3＋ and the ones of three laser crystals （GSGG：Cr^3＋, GGG：Cr^3＋ and ruby） have been made, and the origin of the difference between them has been revealed.

关键词： high-pressure effect electron-phonon interaction R lines admixture of |t22(3T1)e4T2〉 and |t322E〉 laser crystals

Helical ternary complexes of alkaline earth picrates with open-chain crown ether

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Science China Chemistry 2003年第4期46卷 399-406页

作者：刘伟生温永红刘雪原谭民裕 department of Chemistry and National Laboratory of applied Organic Chemistry Lanzhou University Lanzhou 730000 China

Four solid complexes of alkaline earth picrates with N,N,N′,N′-tetraphenyl-3,6,9-trioxaundecanediamide (TTD), M (Pic)2TTD (1, M = Mg; 2, M = Ca; 3, M = Sr; 4, M = Ba), have been prepared and characterized by elemental analysis, conductivity measurement, IR spectra, 1H NMR spectra and TG-DTA techniques. Crystal structure of complex 3 shows that the Sr(II) ion is 9-coordinated by five oxygen atoms from TTD and four oxygen atoms from two bidentate picrates, and the coordination polyhedron is distorted tricapped trigonal prism. TTD as a pentadentate ligand forms a right-handed helical coordination structure. The chelating helical chain has a relative fixed radius and then shows a high coordination selectivity to metal ion. The high selectivity of TTD to alkaline earth ions is explained elementarily from the special coordination structures.

关键词： alkaline earth metal, open chain crown ether, complex, helix coordination structure.

TRANSPORTATION THEORY OF MULTIPLE SCATTERING AND ITS APPLICATION TO SEISMIC CODA WAVES OF IMPULSE SOURCE

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Science in China,Ser.B 1988年第12期31卷 1503-1514页

作者：尚铁樑高龙生 department of applied Physics Harbin Engineering University Institute of Geophysics State Seismological Bureau Beijing

The energy distribution of elastic waves in an infinite elastic medium with uniformly and randomly distributed scatterers has been researched. The scattering process is assumed to be isotropic and without conversions between wave types. We get the equation on the distribution of energe density in time and space covering single as well as multiple scattering. Taking physical symmetry of the field into account, it can be simplified. In the case of small earthquakes, the energy source of elastic waves can be assumed as a short pulse emitted isotropically at t=0. The first-order approximate solution in the 3-dimensional space can be obtained, and it is equivalent to Sato’s solution for single scattering. In the 2-dimensional space the complete analytical solution has been derived by the mathematical inductance which leads to a conclusion that the codas of surface waves can give the Q-factor related to intrinsic absorption. The equation obtained in this paper is more general.

关键词： coda scattering seismic wave maltiple scattering Q-factor.

Nanocrystalline low-silica X zeolite as an efficient ion-exchanger enabling fast radioactive strontium capture

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 15-23页

作者： Hyungmin Jeon Susung Lee Jeong-Chul Kim Minkee Choi department of Chemical and Biomolecular Engineering(BK21 Four) Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Center for Nanomaterials and Chemical Reactions Institute for Basic Science(IBS)Daejeon 34141Republic of Korea

NaA zeolite(Si/Al=1.00)has been commercially applied for capturing radioactive 90Sr^(2+)because of its high surface charge density,effectively stabilizing the multivalent ***,owing to its narrow micropore opening(4.0Å),large micron-sized crystallites,and bulkiness of hydrated Sr^(2+),the Sr^(2+)exchange over NaA has been limited by very slow *** this study,we synthesized nanocrystalline low-silica X by minimizing a water content in a synthesis gel and utilizing a methyl cellulose hydrogel as a crystal growth *** resulting zeolite exhibited high crystallinity and Al-rich framework(Si/Al of approximately 1.00)with the sole presence of tetrahedral Al sites,which are capable of high Sr^(2+)uptake and ion ***,the zeolite with a FAU topology has a much larger micropore opening size(7.4Å)and a much smaller crystallite size(~340 nm)than NaA,which enable significantly enhanced ion-exchange *** to conventional NaA,the nanocrystalline low-silica X exhibited remarkably increased Sr^(2+)-exchange kinetics(>18-fold larger rate constant)in batch *** both the nanocrystalline low-silica X and NaA exhibited comparable Sr^(2+)capacities under equilibrated conditions,the former demonstrated a 5.5-fold larger breakthrough volume than NaA under dynamic conditions,attributed to its significantly faster Sr^(2+)-exchange kinetics.

关键词： Sr^(2+)removal low-silica X zeolite nanocrystal hydrogel methyl cellulose

Oscillating droplet tribometer for sensitive and reliable wetting characterization of superhydrophobic surfaces

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Droplet 2022年第1期1卷 38-47页

作者： Muhammad Junaid Heikki A.Nurmi Mika Latikka Maja Vuckovac Robin H.A.Ras department of applied Physics School of ScienceAalto UniversityEspooFinland department of Bioproducts and Biosystems School of Chemical EngineeringAalto UniversityEspooFinland

Accurate wetting characterization is crucial for the development of next‐generation superhydrophobic ***,wetting properties are measured with a contact angle goniometer(CAG)suitable for a broad range of ***,due to optical errors and challenges in baseline positioning,the CAG method suffers from inaccuracies on superhydrophobic *** we present an improved version of the oscillating droplet tribometer(ODT),which can reliably assess wetting properties on superhydrophobic surfaces by measuring the frictional forces of a water‐based ferrofluid droplet oscillating in a magnetic *** demonstrate that ODT has superior accuracy compared to CAG by measuring the wetting properties of four different superhydrophobic surfaces(commercial Glaco and Hydrobead coatings,black silicon coated with fluoropolymer,and nanostructured copper modified with lauric acid).We show that ODT can detect the small but significant changes in wetting properties caused by the thermal restructuring of surfaces that are undetectable by *** more,unlike any other wetting characterization technique,ODT features an inverse sensitivity:the more repellent the surface,the lower the error of measurement,which was demonstrated by experiments and simulations.

关键词： oscillating frictional wetting