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Efficient photocatalytic reduction of chromium(Ⅵ) using photoreduced graphene oxide as photocatalyst under visible light irradiation

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Journal of Materials Science & Technology 2021年第32期91卷 17-27页

作者： mei yu Jing Shang yu Kuang Department of Environment and Health State Key Joint Laboratory of Environmental Simulation and Pollution ControlCollege of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China

Graphene oxide(GO),a new and promising material,has been widely used as a co-catalyst in photocatalytic reactions;however,its capacity as a sole photocatalyst has rarely been *** this study,ultraviolet(UV) light irradiation was used as a modification method to obtain reduced GO(rGO) *** samples were used as photocatalysts to examine their visible light photocatalytic activity toward hexavalent chromium(Cr(Ⅵ)) *** force microscopy(AFM),X-ray diffraction(XRD),UV-vis spectrophotometry,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),and electron spin resonance(ESR) spectroscopy were applied to interpret the surface and structure changes with UV *** oxygen-containing functional groups(OFGs) on the GO surface were reduced to defective carbons andπ-conjugated C=C(sp^(2) domains) under UV light;this led to a decrease in the interlayer distance between GO sheets,GO fragmentation,and increased disorder on the GO *** restoration of sp^(2) domains led to a narrower band gap of GO,which favored the rGO excitation by visible light to generate electron-hole *** rGO pre-irradiated with UV for 1 h(rGO-1),possessing the highest defect density and electron generation efficiency,exhibited the best Cr(Ⅵ) reduction efficiency,which was about three times that of the GO sample;moreover,it outperformed most of the reported GO-based *** addition,low pH and the addition of citric acid as a hole scavenger could further improve the photocatalytic *** study proves that GO or rGO can be used as a sole photocatalyst under visible light to remove environmental pollutants such as heavy-metal ions,and it paves the way for the development of this kind of material and its UV-irradiation modification for further applications.

关键词： Graphene oxide Chromium(Ⅵ) Defect density UV-irradiation modification Photocatalytic reduction

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Ordering Trees by Their Spectral Radii

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1107-1112页

作者： Ai-mei yu Department of Mathematics Beijing Jiaotong University

Let T be a tree with n vertices and let A（T） be the adjacency matrix of T. Spectral radius of T is the largest eigenvalue of A（T）. Wu et al. [Wu, B.F., yuan, X.Y, and Xiao, E.L. On the spectral radii of trees, Journal of East China Normal University （Natural Science）, 3：22-28 （2004）] determined the first seven trees of order n with the smallest spectral radius. In this paper, we extend this ordering by determining the trees with the eighth to the tenth smallest spectral radius among all trees with n vertices.

关键词： tree spectral radius ordering

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An Analytical Solution for Nearshore Circulation Driven by Focused/Defocused Waves

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China Ocean Engineering 2019年第5期33卷 544-553页

作者： DING yu-mei SHI Fengyan School of Science Tianjin University of Science and Technology Tianjin 300475 China Center for Applied Coastal Research Department of Civil and Environmental Engineering University of Delaware Newark 19716 USA

An offshore shoal or bar refracts ocean surface waves and causes wave focusing/defocusing on the adjacent beach. Wave focal patterns characterized by alongshore variations in wave height, wave angle, and breaking location induce alongshore non-uniformities of wave setup and nearshore circulation, e.g., rip currents and alongshore currents, in the surfzone. A simplified analytic model for nearshore circulation generated by focused/defocused waves on a planar beach is developed and theoretical solutions are obtained using transport stream function and perturbations in alongshore distributions of wave height and wave angle at the breaker line. The analytic model suggests that alongshore currents are strongly affected by a pair of counter-rotating vortices generated shoreward of the wave focal zone. The vortices are persistent, and their strengths depend on the amplitudes of alongshore variations in wave height and wave angle. The alongshore gradient in wave height tends to intensify the vortices while the convergence of wave angle tends to weaken the vortices. Divergent flows associated with the vortices in the surfzone are intense, strengthening alongshore currents in the downstream of the wave focal zone and weakening alongshore currents or causing flows reversal in the upstream. Alongshore currents are modulated by rip currents associated with the wave focusing/defocusing patterns.

关键词： wave focusing and defocusing nearshore circulation rip current alongshore current analytical solution

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Vanishing viscosity limits for the free boundary problem of compressible viscoelastic fluids with surface tension

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Science China Mathematics 2023年第6期66卷 1263-1300页

作者： Xumin Gu yu mei School of Mathematics Shanghai University of Finance and EconomicsShanghai 200433China School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'an 710129China

We consider the free boundary problem of compressible isentropic neo-Hookean viscoelastic fluid equations with surface *** the physical kinetic and dynamic conditions proposed on the free boundary,we investigate the regularity of classical solutions to viscoelastic fluid equations in Sobolev spaces which are uniform in viscosity and justify the corresponding vanishing viscosity *** key ingredient of our proof is that the deformation gradient tensor in Lagrangian coordinates can be represented as a parameter in terms of the flow map so that the inherent structure of the elastic term improves the uniform regularity of normal derivatives in the limit of vanishing *** result indicates that the boundary layer does not appear in the free boundary problem of compressible viscoelastic fluids,which is different from the case studied by mei et al.(2018)for the free boundary compressible Navier-Stokes system.

关键词： free boundary viscoelastic fuid vanishing viscosity compressible fuid elastodynamics

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Influence of Rust Layers on the Corrosion Behavior of Ultra-High Strength Steel 300M Subjected to Wet–Dry cyclic Environment with Chloride and Low Humidity

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 139-146页

作者： Qiang Guo Jian-Hua Liu mei yu Song-mei Li Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and Engineering Beihang University

The influence of rust layers on the corrosion behavior of ultra-high strength steel 300M subjected to a simulated coastal atmosphere was investigated by corrosion weight loss, surface analysis techniques, and electrochemical methods. The results exhibit the presence of a large proportion of γ-FeOOH and α-FeOOH and a small amount of Fe3O4 in the outer rust layer. During the wet-dry cyclic process, the bonding performance and the density of outer rust layer deteriorate with the thickness of outer rust. The inner rust layer plays a main role on protectiveness, which can be attributed to the formation of an ultra-dense and adherent rust film with major constituent of α-FeOOH and α-Fe2O3 on the steel.

关键词： Ultra-high strength steel Wet-dry Chloride Corrosion Rust

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Multi-view video color correction using dynamic programming

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1115-1120页

作者： Shao Feng Jiang Gangyi yu mei Faculty of Information Science and Engineering Ningbo Univ. Ningbo 315211 P. R. China National Key Lab of Software New Technology Nanjing Univ. Nanjing 210093 P. R. China

Color inconsistency between views is an important problem to be solved in multi-view video systems. A multi-view video color correction method using dynamic programming is proposed. Three-dimensional histograms are constructed with sequential conditional probability in HSI color space. Then, dynamic programming is used to seek the best color mapping relation with the minimum cost path between target image histogram and source image histogram. Finally, video tracking technique is performed to correct multi-view video. Experimental results show that the proposed method can obtain better subjective and objective performance in color correction.

关键词： multi-view video color correction dynamic programming video tracking

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Location Service Information Supporting System Based on Ontology

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Journal of Integrative Agriculture 2012年第5期11卷 858-864页

作者： HUANG Dong-mei FANG Qian yu Qing-mei College of Information Shanghai Ocean UniversityShanghai 201306P.R.China

In order to solve the problem of how to collect and manage large amount of location information and improve the accuracy of location service, interactive information supporting system based on ontology and location service is presented in this paper. It can transmit special information about users＇ location to front-end instantaneously, so it is very convenient for their daily life. It makes full use of the available wireless communication, which is easy to arrange and convenient for users.

关键词： ontology location service location information supporting system

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Fishery Web Service Composition Method Based on Ontology

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Journal of Integrative Agriculture 2012年第5期11卷 792-799页

作者： yu Qing-mei WANG Lan HUANG Dong-mei School of Information Technology Shanghai Ocean UniversityShanghai 201306P.R.China

Various fishery information systems have been developed in different times and on different platforms. Wet） service application composition is crucial in the sharing and integration of fishery data and information. In the present paper, a heuristic web service composition method based on fishery ontology is presented, and the proposed web services are described. Ontology reasoning capability was applied to generate a service composition graph. The heuristic function was introduced to reduce the searching space. The experimental results show that the algorithm used considers the services semantic similarity and adiusts web service composition plan by dynamically relying on the empirical data.

关键词： web services composition semantic similarity fishery ontology heuristic function

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Clinical value of contrast-enhanced ultrasound in early diagnosis of small hepatocellular carcinoma (≤ 2 cm)

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World Journal of Clinical Cases 2022年第24期10卷 8525-8534页

作者： Qi mei mei yu Qiong Chen Department of Ultrasound Shanghai Xuhui Dahua HospitalShanghai 200237China Department of Radiology Shanghai Xuhui Dahua HospitalShanghai 200237China

BACKGROUND Hepatocellular carcinoma(HCC)is the most common type of primary liver ***-enhanced ultrasound(CEUS)uses contrast microbubbles during ultrasound,allowing the detection and characterization of malignant focal liver lesions with much higher diagnostic accuracy than conventional ultrasound;however,there are few reports focusing on the pattern of enhancement of CEUS for the diagnosis of HCC smaller than 2 *** To investigate the clinical value of CEUS in the early detection of small HCC with high risk *** A total of 395 patients with 632 nodules at high risk of HCC,who underwent regular follow-up at Xuhui Dahua Hospital from January 2007 to December 2021,were retrospectively *** ultrasonography combined with CEUS was adopted to analyze the echo,size,location,and enhancement characteristics of benign and malignant nodules,as well as the enhancement methods for HCC with different *** The follow-up rate and duration were 92.15%(364/395)and 51.28±45.09 mo,*** ultrasonography combined with CEUS revealed 65(11.80%)nodules with a follow-up diagnosis of HCC,19(3.45%)dysplastic nodules,and 467(84.75%)benign cirrhotic hyperplastic *** 65 cases of confirmed HCC,40(61.54%)were transformed from hypoechoic nodules,9(13.85%)from hyperechoic nodules,and the remaining 16(24.62%)from isoechoic *** differences in CEUS characteristics were found among cirrhotic nodules,dysplastic nodules,and HCC nodules at each *** differences in the enhancement mode were observed between nodules≤1 cm and those 1–2 *** smaller the HCC nodule,the later the contrast agent began to flush and the longer the duration of contrast *** Conventional ultrasonography combined with CEUS could identify small HCC and help monitor patients with an early diagnosis of *** differences in the enhancement mode are noted between nodules≤1 cm and those 1–2 cm.

关键词： Carcinoma Hepatocellular Contrast-enhanced ultrasonography Diagnostic imaging

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Assembly of a Heteronuclear POM {[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n) via Two Kinds of Clusters as the Basic Bridge Unit

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Chinese Journal of Structural Chemistry 2018年第10期37卷 1612-1618页

作者： DAI yu-mei XU Jie Minnan Science and Technology Institute Fujian Normal UniversityQuanzhou 362332China

A novel 3D hetero-nuclear framework,namely{[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n)(1),was obtained by hydrothermal *** metal centers(including sodium/potassium or/and copper)were coordinated to acetate anions in such two heteronuclear clusters,***,nine kinds of binding modes for acetate anions were illustrated in polymer 1,with the first reported pentadentate coordination mode for acetate ligand.

关键词： hydrothermal synthesis acetate Hgand heteronuclear clusters of sodium/potassium and copper

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