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metal-enhanced fluorescence of graphene oxide by palladium nanoparticles in the blue-green part of the spectrum

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Chinese Physics B 2016年第11期25卷 576-583页

作者： A Omidvar m R Rashidian Vaziri B Jaleh N Partovi Shabestari m Noroozi Department of Physics Bu-Ali Sina University Laser and Optics Research School NSTRI Tehran Iran Center for Research and Development of Petroleum Technologies at Kermanshah Research Institute of Petroleum Industry (RIPI)

Graphene oxide（GO） has a wide fluorescence bandwidth,which.m.kes it a prospective candidate for numerous *** many of these applications,the fluorescence yield of GO should be further *** sp2-hybridized carbons in GO confine the π-*** recombination of electron-hole pairs in such sp2 clusters is the source of fluorescence in this *** nanoparticles are good catalysts for sp2 bond *** report on the preparation of GO,palladium nanoparticles and their nanocomposites in two different *** is shown that palladium nanoparticles can considerably enhance the intrinsic fluorescence of GO in the blue-green part of the visible light *** enhancement has been attributed to the catalytic role of palladium nanoparticles in increasing the number of sp2 bonds of GO with the molecules of the surrounding *** is shown that palladium nanoparticles could be the nanoparticle of choice for fluorescence enhancement of GO because of their catalytic role in sp2 bond formation.

关键词： palladium formations considerably bonds Palladium attributed numerous Fluorescence visible bandwidth

SOmE OSCILLATION CRITERIA FOR SECOND ORDER NONLINEAR FUNCTIONAL ORDINARY DIFFERENTIAL EQUATIONS

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Acta math.m.tica Scientia 2007年第3期27卷 602-610页

作者： E.m.E.Zayed m.A.El-moneam math.m.tics Department Faculty of ScienceZagazig UniversityZagazigEgypt

The main objective of this article is to study the oscillatory behavior of the solutions of the following nonlinear functional differential equations（a（t）x＇（t））＇＋δ1p（t）x＇（t）＋δ2q（t）f（x（g（t））） = 0,for 0 ≤ to≤ t, where 51 = ：El and δ±1. The functions p,q,g ： [t0, ∞） → R, f ： R → are continuous, a（t）〉 0,p（t） ≥0,q（t）〉 0 for t ≥ to,lirn g（t） = ∞, and q is not identically zero on any subinterval of [to, ∞）. moreover, the functions q（t）, g（t）, and a（t） are continuously differentiable.

关键词： Oscillatory and nonoscillatory solutions nonlinear functional differential equations

Scaling group transformation for mhD boundary layer flow over permeable stretching sheet in presence of slip flow with Newtonian heating effects

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Applied math.m.tics and mechanics(English Edition) 2014年第11期35卷 1375-1386页

作者： A.A.AFIFY m.J.UDDIN m.FERDOWS Department of math.m.tics Faculty of Science Helwan University American International University-Bangladesh Department of math.m.tics University of Dhaka

Taking into account the slip flow effects, Newtonian heating, and thermal radiation, two-dimensional magnetohydrodynamic （mhD） flows and heat transfer past a permeable stretching sheet are investigated numerically. We use one parameter group transformation to develop similarity transformation. By using the similarity transformation, we transform the governing boundary layer equations along with the boundary conditions into ordinary differential equations with relevant boundary conditions. The obtained ordinary differential equations are solved with the fourth-fifth order Runge-Kutta- Fehlberg method using mAPLE 13. The present paper is compared with a published one. Good agreement is obtained. Numerical results for dimensionless velocity, temperature distributions, skin friction factor, and heat transfer rates are discussed for various values of controlling parameters.

关键词： magnetohydrodynamic (mhD) heat transfer boundary layer Lie groupanalysis Newtonian heating slip flow

TANGENT UNIT-VECTOR FIELDS:NONABELIAN h.m.TOPY INVARIANTS AND ThE DIRIChLET ENERGY

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Acta math.m.tica Scientia 2010年第5期30卷 1357-1399页

作者： A.majumdar J.m.Robbins m.Zyskin math.m.tical Institute University of Oxford24-29 St.GilesOxford OX1 3LBUK School of math.m.tics University of BristolUniversity WalkBristol BS8 1TWUK Department of math.m.tics SETB 2.454-80 Fort BrownBrownsvilleTX 78520USA

Let O be a closed geodesic polygon in S2. maps from O into S2 are said to satisfy tangent boundary conditions if the edges of O are mapped into the geodesics which contain th.m. Taking O to be an octant of S2, we compute the infimum Dirichlet energy 6（h） for continuous maps satisfying tangent boundary conditions of arbitrary h.m.topy type h. The expression for C（h） involves a topological invariant - the spelling length - associated with the （non-abelian） fundamental group of the n-times punctured two-sphere, π1（S2 - {s1,..., sn}, ＊）. The lower bound for C（h） is obtained from combinatorial group theory arguments, while the upper bound is obtained by constructing explicit representatives which, on all but an arbitrarily small subset of O, are alternatively locally conformal or anticonformal. For conformal and anticonformal classes （classes containing wholly conformal and anticonformal representatives respectively）, the expression for C（h） reduces to a previous result involving the degrees of a set of regular values sl,…… sn in the target 82 space. These degrees may be viewed as invariants associated with the abelianization of vr1（S2 - {s1,..., sn}, ＊）. For nonconformal classes, however, ε（h） may be strictly greater than the abelian bound. This stems from the fact that, for nonconformal maps, the number of preimages of certain regular values may necessarily be strictly greater than the absolute value of their degrees. This work is motivated by the theoretical modelling of nematic liquid crystals in confined polyhedral geometries. The results imply new lower and upper bounds for the Dirichlet energy （one-constant Oseen-Frank energy） of reflection-symmetric tangent unitvector fields in a rectangular prism.

关键词： harmonic maps conformal maps algebraic topology non-abelian h.m.topy invariants eombinatorics liquid crystals

Estimate of fine sediment deposit dynamics over a gravel bar using photography analysis

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International Journal of Sediment Research 2013年第2期28卷 220-233页

作者： B.CAmENEN m.JODEAU m.JABALLAh Irstea HHLY5 rue de la DouaCS 70077-69626 Villeurbanne cedexFrance DrResearch scientist EDF-LNhE 6 quai Watier78401 Chatou cedexFrance DrResearch scientist Irstea HHLY5 rue de la DouaCS 70077-69626 Villeurbanne cedexFrance PhD candidate

Three different methods to analyse fine sediment deposits on a gravel bar using pictures are presented in this paper.A manual digitization and deposits zone delineation are performed as well as two different automated *** three methods are applied on aerial pictures taken in 2006 by a drone from a height around 150 m above the study site. Two other sets of pictures taken in 2010 are also studied:the first set was obtained from the left side bank of the river at approximately 15m above the gravel bar whereas the second one was taken from a helicopter flying 600 m above the *** methods were used to estimate the surface of fine sediment deposits before and after flushing events. They yield similar results even if the first automated procedure is able to capture smaller patches of fine *** total surface of fine sediment deposits seems to be similar before and after a flushing event,but the distribution appears quite *** a flushing event,a significant amount of fine sediment deposits are mixed with coarser *** the flushing event,one can observe more large fine sediment deposits located on the downstream part of the secondary channel and at the channel *** of the small fine sediment deposit patches were washed out. A short discussion is provided on the possible dynamics of fine sediment deposits over the gravel bar.

关键词： Fine sediment deposits Photo analysis Automated procedure Flushing event

A semi-relativistic treatment of spinless particles subject to the nuclear Woods-Saxon potential

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Chinese Physics C 2013年第6期37卷 12-17页

作者： m.h.m.avi S.m.Ikhdair A.A.Rajabi Department of Basic Sciences Shahrood Branch Islamic Azad University Physics Department Near East University Department of Physics An-Najah National University Physics Department Shahrood University of Technology

By applying an appropriate Pekeris approximation to deal with the centrifugal term, we present an approximate systematic solution of the two-body spinless Salpeter （SS） equation with the Woods-Saxon interaction potential for an arbitrary/-state. The analytical semi-relativistic bound-state energy eigenvalues and the corresponding wave functions are calculated. Two special cases from our solution are studied： the approximated SchrSdinger- Woods-Saxon problem for an arbitrary/-state and the exact s-wave （l=0）.

关键词： spinless Salpeter equation usual Woods-Saxon potential Nikiforov-Uvarov method

Large scale silver nanowires network fabricated by meV hydrogen (h＋) ion beam irradiation

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Chinese Physics B 2016年第4期25卷 268-273页

作者： honey S Naseem S Ishaq A maaza m Bhatti m T Wan D Center of Excellence in Solid State Physics University of the Punjab Lahore Pakistan National Center for Physics Quaid-i-Azam University Islamabad 44000 Pakistan UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology College of Graduate Studies University of South Africa Muckleneuk ridge P. O. Box 392 Pretoria South Africa Nanosciences African Network (NANOAFNET) iThemba LABS National Research Foundation Old Faure road P. O. Box 722 Somerset West 7129 South Africa Department of Physics Bahauddin Zakariya University Multan 60800 Pakistan School of materials Science and Engineering Shanghai University Shanghai 201900 China

A random two-dimensional large scale nano-network of silver nanowires （Ag-NWs） is fabricated by meV hydrogen （h＋） ion beam irradiation. Ag-NWs are irradiated under h＋ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by h＋ ion beam-induced welding of Ag-NWs at intersecting positions. h＋ ion beam induced welding is confirmed by transmission electron microscopy （TEm） and scanning electron microscopy （SEm）. moreover, the structure of Ag NWs remains stable under h＋ ion beam, and networks are optically transparent. morphology also remains stable under h＋ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under meV h＋ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps： ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from meV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices.

关键词： Ag nanowires h+ ion irradiation nanowelding large scale nano-network optical properties

What is going on in magnesium alloys？

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Journal of materials Science & Technology 2018年第2期34卷 245-247页

作者： X.J. Wang D.K. Xu R.Z. Wu X.B. Chen Q.m. Peng L. Jin Y.C. Xin Z.Q. Zhang Y. Liu X.h. Chen G. Chen K.K. Deng h.Y. Wang School of materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Key Laboratory of Nuclear materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory of Superlight materials & Surface Technology (ministry of Education) Harbin Engineering University Harbin 150001 China School of Engineering RMIT University City Campus Carlton VIC 3053 Australia State Key Laboratory of metastable materials Science and Technology Yanshan University Qinhuangdao 066004 China National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong University Shanghai 200240 China College of materials Science and Engineering Chongqing University Chongqing 400030 China Key Lab of Electromagnetic Processing of materials Ministry of Education Northeastern UniversityShnenyang 110819China Key Laboratory of Lightweight and high Strength Structural materials of Jiangxi Province Nanchang University Nanchang 330031 China School of Ch.m.cal Engineering and Technology Tianjin University Tianjin 300350 China Shanxi Key Laboratory of Advanced magnesium-Based materials Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Automobile materials of ministry of Education & School of materials Science and Engineering Jilin University Changchun 130025 China

China has been developed into one of the most active regions in terms of both fundamental and applied research on magnesium （mg） and its alloys in the world from a solid base laid by its prominent metallurgist and materials scientists over the past decades. Nowadays, a large number of young-generation researchers have been inspired by their predecessors and become the key participants in the fields of mg alloys, which consequently led to the establishment of China Youth Scholar Society for magnesium Alloys Research in 2015. Since then, the first two China Youth Scholars Symposiums on mg Alloys Research had been held at harbin （2015） and Chongqing （2016） China, respectively. A number of crucial research inter- ests related to fundamental and applied mg research were discussed at the conferences and summarized in this short perspective, aiming to boost far-reaching initiatives for development of new mg-based materials to satisfy the requirements for a broad range of industrial employments. herein, four main aspects are included as follows： i） Plastic deformation mechanism and strengthening strategy, ii） Design and development of new mg-based materials, iii） Key service properties, and iv） New processing technologies.

关键词： mg alloys Plastic deformation Strengthening Alloying design high performance Corrosion Fatigue behavior Creep Processing technologies Purification

Effects of surface finish and treatment on the fatigue behaviour of vibrating cylinder block using frequency response approach

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第3期7卷 352-360页

作者： RAhmAN m. m. ARIFFIN A. K. Computational and Experimental mechanics Group Department of Mechanical and Materials Engineering Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor DE Malaysia

This paper presents the effects of surface finish and treatment on the high cycle fatigue behaviour of vibrating cylinder block of a new two-stroke free piston engine at complex variable amplitude loading conditions using frequency response approach. Finite element modelling and frequency response analysis was conducted using finite element analysis software Package ***/*** and fatigue life prediction was carded out using *** software. Based on the finite element results, different frequency response approach was applied to predict the cylinder block fatigue life. Results for different load histories and material combinations are also discussed. Results indicated great effects for all surface finish and treatment. It is concluded that polished and cast surface finish conditions give the highest and lowest cylinder block lives, respectively; and that Nitrided treatment leads to longest cylinder block life. The results were used to draw contour plots of fatigue life and damage in the worst or most damaging case.

关键词： Finite element method Fatigue life Surface finish Surface treatment Frequency response approach