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Surface Plasmons and Optical Properties of TiO_(2)/X(X=Au and Ag)Nanostructure Thin Films

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Chinese Physics Letters 2013年第9期30卷 116-119页

作者： A.Zolanvari h.Sadeghi R.Norouzi A.Ranjgar Department of Physics Faculty of ScienceArak UniversityArak 38156-8-8349Iran

TiO_(2)/X(X=Au and Ag)nanolayers are fabricated by depositing TiO_(2)films using rf magnetron sputtering on thin quartz substrates embedded with Au and Ag *** of light absorption of the nanostructural layers is *** plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of *** light absorption enhancement of synthesized structure in comparison to TiO_(2)is originated from near-field enhancement caused by the plasmonic effect of metallic nanoparticles,which can be demonstrated by the optical absorption *** show that plasmon modes can exist for the infrared region of the optical ***,we analyze the optical properties of the metal-insulator films,in order to clarify the role of metal inclusions in the TiO_(2)dielectric *** band gaps of the nanolayer films are calculated by using Tauc’s relation,and the𝑜values of optical band gaps with the variation composition are found from 1.80 to *** gap narrowing and absorption in the visible spectral region induced by the incorporation of TiO_(2)/X(X=Au and Ag)nanolayers enable the design of nanostructured thin films to be achieved for photocatalysts and solar energy converters.

关键词： absorption structure arrangement

Biosorption and retention of orthophosphate onto Ca(Oh)_2-pretreated biomass of Phragmites sp.

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Journal of Environmental Sciences 2016年第7期28卷 49-59页

作者： Giorgos Markou Dimitris Mitrogiannis Koenraad Muylaert Abuzer Celekli hüseyin Bozkurt Department of Natural Resources Management and Agricultural Engineering Agricultural University of AthensIera Odos 75Athens 11855Greece Laboratory Aquatic Biology KU Leuven KulakE.Sabbelaan 53Kortrijk 8500Belgium Department of Biology Faculty of Art and ScienceGaziantep UniversityGaziantep 27310Turkey Department of Food Engineering Faculty of EngineeringGaziantep UniversityGaziantep 27310Turkey

The biosorption of phosphorus in the form of orthophosphate（Po） from wastewater using biomass as the sorbent is of potential importance because the Po-loaded biomass could be applied in the agricultural sector as fertilizer and soil conditioner. however, biomass generally displays a very low affinity for Posorption and therefore biomass surface modification is required. In the present study, the biomass（as model grinded leaves of Phragmites sp. were used）was pretreated with Ca（Oh）2to enhance Pobiosorption capacity（qe）. The results indicate that the alkaline pretreatment resulted in a modification of surface functional groups. It was concluded that the main sorption mechanisms were ligand exchange and electrostatic attraction. A series of experiments were conducted to investigate the performance of the pretreated biomass for Pouptake under various conditions. Isotherm and thermodynamic studies were also applied and analyzed. The biosorption process was best described by the pseudo-second order kinetic model and Langmuir isotherm, which gave a qmaxof 12.27 mg P/g at 25°C and p h 7. The Ca（Oh）2treated Phragmites biomass applied in this study for Porecovery may present some potential advantages in terms of costs and environmental impact.

关键词： Biosorption Ligand exchange Nutrient recovery Phosphorus removal Pretreatment

Fano Factor in Strained Graphene Nanoribbon Nanodevices

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Chinese Physics Letters 2017年第11期34卷 114-118页

作者： Walid Soliman Mina D.Asham Adel h.Phillips Faculty of Engineering Benha UniversityBenhaEgypt Faculty of Engineering AinShams UniversityCairoEgypt

We investigate the Fano factor in a strained armchair and zigzag graphene nanoribbon nanodevice under the effect of ac field in a wide range of frequencies at different temperatures （10？K–70？K）. This nanodevice is modeled as follows： a graphene nanoribbon is connected to two metallic leads. These two metallic leads operate as a source and a drain. The conducting substance is the gate electrode in this three-terminal nanodevice. Another metallic gate is used to govern the electrostatics and the switching of the graphene nanoribbon channel. The substances at the graphene nanoribbon/metal contact are controlled by the back gate. The photon-assisted tunneling probability is deduced by solving the Dirac eigenvalue differential equation in which the Fano factor is expressed in terms of this tunneling probability. The results show that for the investigated nanodevice, the Fano factor decreases as the frequency of the induced ac field increases, while it increases as the temperature increases. In general, the Fano factors for both strained armchair and zigzag graphene nanoribbons are different. This is due to the effect of the uniaxial strain. It is shown that the band structure parameters of graphene nanoribbons at the energy gap, the C–C bond length, the hopping integral, the Fermi energy and the width are modulated by uniaxial strain. This research gives us a promise of the present nanodevice being used for digital nanoelectronics and sensors.

关键词： Fano Factor in Strained Graphene Nanoribbon Nanodevices

Approximation approach to the SRM based on root decomposition in the simulation of spatially varying ground motions

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 363-372页

作者： Wu Yongxin Gao Yufeng Li Dayong Xu Changjie Ali h Mahfouz Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Institute of Engineering Safety and Disaster Prevention Hohai University Geotechnical Research Institute Hohai University Department of Civil Engineering Shandong University of Science and Technology Research Center of Coastal and Urban Geotechnical Engineering Zhejiang University College of Engineering Jazan University

The spectral representation method （SRM） is widely used to simulate spatially varying ground motions. This study focuses on the approximation approach to the SRM based on root decomposition, which can improve the efficiency of the simulation. The accuracy of the approximation approach may be affected by three factors： matrix for decomposition, distribution of frequency interpolation nodes and elements for interpolation. The influence of these factors on the accuracy of this approach is examined and the following conclusions are drawn. The SRM based on the root decomposition of the lagged coherency matrix exhibits greater accuracy than the SRM based on the root decomposition of the cross spectral matrix. The equal energy distribution of frequency interpolation nodes proposed in this study is more effective than the counter pith with an equal spacing. Elements for interpolation do not have much of an effect on the accuracy, so interpolation of the elements of the decomposed matrix is recommended because it is less complicated from a computational efficiency perspective.

关键词： ground motions simulation spectral representation method spatially varying approximation root decomposition

Study of Thermal and hydraulic Performances of Circular and Square Ribbed Rough Microchannels Using LBM

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Journal of Thermal Science 2015年第6期24卷 549-556页

作者： M.A.Taher h.D.Kim Y.W Lee Department of Mechanical and Automotive Engineering Pukyong National University Department of Mechanical Engineering Andong National University

The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this *** micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is *** roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel *** friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness *** thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of *** results have been compared with previous published works and it is found to be in very good agreement.

关键词： Lattice-Boltzmann Friction factor Knudsen number Surface Roughness

Effect of Nitrogen Doping on the Electrical Properties of 3C-SiC Thin Films for high-Temperature Sensors Applications

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 168-174页

作者： h.K.E.Latha A.Udayakumar V.Siddeswara Prasad Department of Instrumentation Technology Siddaganga Institute of Technology Materials Science Division Council of Scientific and Industrial Research-National Aerospace Laboratories

3C-SiC is a promising structural material for piezoresistive sensors used in high-temperature applications. For sensor development, the preparation of sensor materials and study of its electrical properties, such as resistivity, barrier height of grain boundaries, and temperature coefficient of resistivity, are important in addition to structural properties and these have to be optimized. In the present work, 3C-SiC thin film with in situ doping of nitrogen is prepared through low- pressure chemical vapor deposition by using methyl trichloro silane, ammonia, and hydrogen as precursors. Electrical properties of deposited 3C-SiC thin films with varying nitrogen doping concentration through four probe technique are studied. Atomic force microscopy investigations are carried out to study the grain size on and average root-mean-squared roughness 3C-SiC thin films. A decrease in the degree of crystallinity is observed in nitrogen-doped 3C-SiC thin films. The sheet resistivity of nitrogen-doped 3C-SiC thin film is found to decrease with increase in temperature in the range from 303 to 823 K. The sheet resistivity, average temperature coefficient of resistance, and barrier height of the grain boundaries of film doped with 17 at.% of nitrogen are 0.14 cm, -1.0 x 10-n/K, and 0.01 eV, respectively. Comparing all the nitrogen-doped 3C-SiC thin films, the film doped with 17 at.% of nitrogen exhibits an improved structural and electrical properties and it can be used as sensing material for high-temperature applications.

关键词： Low-pressure chemical vapor deposition (LPCVD) 3C-SiC thin film Resistivity Barrier height of grain boundaries: Temperature coefficient of resistivitv (TCR)

Low-complexity online correction and calibration of pedestrian dead reckoning using map matching and GPS

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Geo-Spatial Information Science 2019年第2期22卷 114-127,I0004页

作者： Fabian hölzke Johann-P.Wolff Frank Golatowski Christian haubelt Institute of Applied Microelectronics and CE University of RostockRostockGermany

Dead Reckoning is a relative positioning scheme that is used to infer the change of position relative to a point of origin by measuring the traveled distance and orientation *** Dead Reckoning(PDR)applies this concept to walking *** method can be used to track someone's movement in a building after a known landmark like the building's entrance is ***,the movement of a foot and the corresponding direction change is measured and summed up,to infer the current *** and integrating the corresponding physical parameters,*** inertial sensors,introduces small errors that accumulate quickly into large distance *** of a buildings geography may reduce these errors as it can be used to keep the estimated position from moving through walls and onto likely *** this paper,we use building maps to improve localization based on a single foot-mounted inertial *** describe our localization method using zero velocity updates to accurately compute the length of individual steps and a Madgwick filter to determine the step *** though the computation of individual steps is quite accurate,small errors still accumulate in the long *** show how correction algorithms using likely and unlikely paths can rectify errors intrinsic to pedestrian dead reckoning tasks,such as orientation and displacement drift,and discuss restrictions and disadvantages of these *** also present a method of deriving the initial position and orientation from GPS *** verify our PDR correction methods analyzing the corrected and raw trajectories of six participants walking four routes of varying length and complexity through an office building,walking each route three *** quantitative results show an endpoint accuracy improvement of up to 60%when using likely paths and 23%when using unlikely ***,both approaches can also decrease accuracy in certain *** identify those scenarios and

关键词： Indoor localization Pedestrian Dead Reckoning(PDR) Inertial Navigation System(INS) map matching Zero Velocity Update(ZUPT)

Reactive DC Magnetron Sputter Deposited Titanium-Copper-Nitrogen Nano-Composite Thin Films with an Argon/Nitrogen Gas Mixture

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Plasma Science and Technology 2010年第6期12卷 681-687页

作者： A.RAhMATI h.BIDADI K.AhMADI F.hADIAN Faculty of sciences Vali-e-Asr University of Rafsanjan Faculty of physics University of Tabriz Department of physics Islamic Azad University of Tabriz Materials and Energy Research Centre(MERC)

A sintered Ti13Cus7 target was sputtered by reactive direct current （DC） magnetron sputtering with a gas mixture of argon/nitrogen for different sputtering powers. Titanium-coppernitrogen thin films were deposited on Si （111）, glass slide and potassium bromide （KBr） substrates. Phase analysis and structural properties of titanium-copper-nitrogen thin films were studied by X-ray diffraction （XRD）. The chemical bonding was characterized by Fourier transform infrared （FTIR） spectroscopy. The results from XRD show that the observed phases are nano-crystallite cubic anti rhenium oxide （anti ReO3） structures of titanium doped Cu3N （Ti：Cu3N） and nanocrystallite face centered cubic （fcc） structures of copper. Scanning electron microscopy and energy dispersive X-ray spectroscopy （SEM/EDX） were used to determine the film morphology and atomic titanium/copper ratio, respectively. The films possess continuous and agglomerated structure with an atomic titanium/copper ratio （-0.07） below that of the original target （- 0.15）. The transmittance spectra of the composite films were measured in the range of 360 nm to 1100 nm. Film thickness, refractive index and extinction coefficient were extracted from the measured transmittance using a reverse engineering method. In the visible range, the higher absorption coefficient of the films prepared at lower sputtering power indicates more nitrification in comparison to those prepared at higher sputtering power. This is consistent with the formation of larger Ti：Cu3N crystallites at lower sputtering power. The deposition rate vs. sputtering power shows an abrupt transition from metallic mode to poisoned mode. A complicated behavior of the films＇ resistivity upon sputtering power is shown.

关键词： nano-composite reactive magnetron sputtering Ti doped Cu3N

Dynamic simulation of beam-like structure with a crack subjected to a random moving mass oscillator

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Earthquake Engineering and Engineering Vibration 2009年第3期8卷 447-458页

作者： M.M.Ettefagh M.h.Sadeghi M.Rezaee Vibration and Modal Analysis Laboratory 51666-14766Department of Mechanical EngineeringUniversity of TabrizTabrizIran

In this paper, dynamic simulation of a beam-like structure with a transverse open crack subjected to a random moving mass oscillator is investigated. The simultaneous effect of a crack and a random oscillator has not been addressed up to now. The crack in the beam at different locations and with different depths is considered as one group of damage, each as an individual imperfection. In addition, bearing immobility is considered as another type of problem in the beam. Mass, stiffness, damping and velocity of the oscillator are assumed to be random parameters. An improved perturbation technique is applied to reduce the simulation time. It was found that there is a maximum value of the variance of each uncertain parameter, in which the maximum reliability of the perturbation method can be achieved, and that this maximum value can be obtained by the Alpha-hilber Monte-Carlo simulation method. The simulation results reveal that the mass and the velocity uncertainty cause high uncertainty in the deflection of the beam. Also, the pattern of the deflection is not affected by different random oscillator parameters, and as a result, the type of damage can be identified even with high uncertainty. Moreover, the deflection in the nodes around the mid-span of the beam provides the best information regarding the imperfections, and consequently leads to the best sensor locations in an actual experiment.

关键词： bridge-vehicle interaction moving mass oscillator random parameters Monte-Carlo simulation perturbation method