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Structural morphological and Optical Properties of SnSb_2S_4 Thin Films Grown by Vacuum Evaporation method

Journal of materials Science & Technology 2014年第10期30卷 1006-1011页

作者： n.Khedmi m.ben Rabeh m.Kanzari Laboratoire de Photovoltaques et matriaux de Semi-conducteurs-EnIT-Universit de Tunis el manar BP 37le belvedere1002 TunisTunisie Laboratoire de Photovoltaques et matriaux de Semi-conducteurs-EnIT-IPEITunis montfleury-Universit de Tunis Tunisie

SnSb2S4 thin films were prepared from powder by thermal evaporation under vacuum of 1.33 × 10^-4 Pa （ 10^-6 Torr） on unheated glass substrates. The effect of thickness on the structural, morphological and optical properties of SnSb2S4 thin films was investigated. Films thickness measured by interference fringes method varied from 50 to 700 nm. X-ray diffraction analysis revealed that all the SnSb2S4 films were polycrystalline in spite without heating the substrates and the crystallinity was improved with increasing film thickness. The microstructure parameters： crystallite size, strain and dislocation density were calculated. It was observed that the crystallite size increased and the crystal defects decreased with increasing film thickness. In addition, by increasing the film thickness, an enhancement in the surface roughness root-mean-square （RmS） increased from 2.0 to 6.6 nm. The fundamental optical parameters like band gap, absorption and extinction coefficient were calculated in the strong absorption region of transmittance and reflectance spectrum. The optical absorption measurements indicated that the band （Eg） gap of the thin films decreased from 2.10 to 1.65 eV with increasing film thickness. The refractive indexes were evaluated in transparent region in terms of envelope method, which was suggested by Swanepoul. It was observed that the refractive index increased with increasing film thickness.

关键词： Ternary system Thermal evaporation technique Thin films Thickness Atomic force microscopy (AFm)

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Cooperative Target Fencing of multiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of Systems Science & Complexity 2024年第1期37卷 136-151页

作者： PAn Zini ch.n ben m Department of mech.nical and Automation Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem for n-dimensional systems and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull formed by the ***,the dynamics of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the communication network and collision avoidance among the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a numerical example.

关键词： multi-agent systems networked systems target fencing

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Influences of nanoparticles and chain length on thermodynamic and electrical behavior of fluorine liquid crystals

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ch.nese Physics B 2022年第10期31卷 410-416页

作者： Ines ben Amor Lotfi Saadaoui Abdulaziz n.Alharbi Talal m.Althagafi Taoufik Soltani Université Tunis El manar Laboratoire de Physique de la Matiére Molle et de la Modélisation Electromagnétique2092 Tunis Physics Department College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

Hydrogen-bonded polar nematic liquid crystal series with the general formula n OBAF(n = 7-12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry(DSC) and polarized optical microscopy(POm). The complexes with short alkyl chains(n = 7, 8) present a wide nematic range and monotropic smectic F mesophase, whereas the longer alkyl chain(n = 10-12) analogues show high melting and low clearing mesomorphic liquid crystals. The thermal range of the mesophase and the birefringence increase with chain length decreasing. Furthermore, the effect of the nanoparticles(LinbO_(3)) on the thermal and the electrical behavior of 8OBAF are investigated. The presence of LinbO_(3) nanoparticles increases the conductivity and reduces the resistivity of the complex.

关键词： fluorine liquid crystal polar nematic ferroelectric nanoparticles thermal stability dielectric behavior

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magnetic and specific heat studies of the frustrated Er_2mn_2O_7 compound

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Journal of Rare Earths 2013年第1期31卷 54-59页

作者： n.ben Amor m.Bejar E.Dhahri m.A.Valente P.Lachkar E.K.Hlil Laboratory of Applied Physics Faculty of Sciences of SfaxBP 1171University of Sfax I3n and Physics Department University of Aveiro mCmF Néel InstitutCNRS25 avenue des MartyrsBuilding FBP 16638042 Grenoble cedex 9France mCBT Institut NéelCNRS25 avenue des MartyrsBuilding EBP 16638042 Grenoble cedex 9France

A new Erzmn207 compound was synthesized by the ceramic method and its crystal structure was characterized LJsing powder X-ray diffraction （XRD） and observed by scanning electron microscopy （SEm）. The magnetic properties were investigated using a BS2 magnetometer and the heat capacity was studied using a quantum design （PPmS）. The structural study revealed that this compound was monophasic and crystallized in the monoclinic system with the P2/m space group. magnetization measurements were carried out in the temperature range of 1.8-200 K under an applied magnetic field of 0.05 T. A crossover from a room temperature para- magnetic phase to an antiferromagnetic one at low temperature was detected from the magnetic study. The magnetic susceptibility, in the paramagnetic region above 40 K, was found to present a simple Curie-Weiss type behavior. From the specific heat （G,） measurements in magnetic fields up to 5 T, we noted the presence of a wide peak characteristic of a second order magneto-structural transition.

关键词： magnetic frustration magnetic phase transition specific heat rare earths

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Substrate Temperature-Dependent Physical Properties of Thermally Evaporated Sn4Sb6S13 Thin Films

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Acta metallurgica Sinica(English Letters) 2016年第1期29卷 79-88页

作者： A. Harizi m. ben Rabeh m. Kanzari Laboratoire de Photovoltaique et materiaux Semiconducteurs departement genie industriel ENIT-Universite Tunis E1 Manar BP 37 Le belvedere 1002 Tunis Tunisie Institut Preparatoire aux Etudes d'Ingenieurs de Tunis Universite de Tunisie Montfleury Tunisia

In this work, the homogenous thin films of sulfosalt Sn4Sb6S13 were successfully synthesized by the thermal evaporation technique onto coming 7059 glass substrates heated at various temperatures in the range of 30--200 ℃. The surface morphology and structural characteristics of Sn4Sb6S13 films were analyzed by atomic force microscopy, X-ray diffraction, and energy-dispersive X-ray, respectively. The X-ray diffraction analysis revealed that Sn4Sb6S13 thin films crystallized in monoclinic structure according to a preferential direction （6 11）. An improvement in the structural properties by increasing the substrate temperature was observed. The values of some important parameters such as absorption coefficient （x）, band gap （Eg）, refractive index （n）, extinction coefficient （k）, and dielectric constant （Eg） of thin film were determined. The absorption coefficient was larger than 105 cm-l in the visible range. The electron transition of Sn4Sb6S13 films was direct allowed with the values that decreased （2-1.69 eV） by increasing substrate temperature from 30 to 200 ℃,The dispersion data obeyed the single oscillator relation of the Wemple-DiDomenico model and Cauchy model. The electrical free carrier susceptibility and the carrier concentration of the effective mass ratio were estimated according to the model of Spitzer and Fan.

关键词： Thin film Thermal evaporation technique X-ray diffraction Optical parameters

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Predictability of Plastic Parts Behaviour made from Rapid manufacturing

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Tsinghua Science and Technology 2009年第S1期14卷 100-107页

作者： mario monzón Pedro m Hernández Antonio n benítez maría D marrero ngel Fernández Department of mech.nical Engineering Las Palmas de Gran Canaria University Las Palmas 35017 Spain AITIIP Foundation Cogullada Technologic Park Zaragoza 50014 Spain

One of the most important issues to resolve in parts manufactured from rapid manufacturing (Rm) technologies is to know their behavior working under real conditions. Total quality manufacturing (TQm) is only possible if mech.nical properties are well known in the design stage depending on the processing parameters. This work is mainly focused on testing of several samples made with different selective laser sintering (SLS) parameters and technologies. This procedure is the starting point to establish a basis for designing for Rm and the standardization of Rm testing. The experiments and the analysis of variance (AnOVA) analyzed the effects of several factors on mech.nical properties. The SLS technologies were 3DSystem and EOS. The results show which factor has a large effect on the variables and the interaction between them. The conclusions are very useful for developing rules for designing (designing for Rm) and creating new standard rules (ISO, AISI, and DIn) for Rm materials and parts testing. The AnOVA gives a better knowledge of the effects of these factors and eliminates unimportant parameters.

关键词： laser sintering rapid manufacturing (Rm) analysis of variance (AnOVA) rapid prototyping additive manufacturing selective laser sintering (SLS)

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Semi-global leader-following output consensus of heterogeneous systems subject to actuator position and rate saturation

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Autonomous Intelligent Systems 2021年第1期1卷 91-103页

作者： Panpan Zhou ben m.ch.n Department of mech.nical and Automation Engineering The Chinese University of Hong KongShatinN.T.Hong Kong

We study in this paper a semi-global leader-following output consensus problem for multiple heterogeneous linear systems in the presence of actuator position and rate saturation over a directed *** each follower,via the low gain feedback design technique and output regulation theory,both a state feedback consensus protocol and an output feedback consensus protocol are *** the output feedback case,different distributed observers are designed for the informed followers and uninformed followers to estimate the state of the leader and the follower *** show that the semi-global leader-following output consensus of heterogeneous linear systems can be achieved by the two consensus protocols if each follower is reachable from the leader in the directed communication topology.

关键词： multi-agent system Output consensus Low gain feedback

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Photoelectrochemical activity of ZnO:Ag/rGO photo-anodes synthesized by two-steps sol-gel method

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ch.nese Physics B 2022年第5期31卷 691-702页

作者： D ben Jemia m Karyaoui m A Wederni A Bardaoui m V martinez-Huerta m Amlouk R chtourou Laboratory of nanomaterials and Renewable Energy Systems LAnSER Research and Technology Center of EnergyBorj-Cedria Science and Technology ParkBP 952050 Hammam-LifTunisia Faculty of Science of Tunis University of Tunis El ManarTunisia Laboratory of Physics of materials and nanomaterials Applied to the Environment(LaPhymnE) Faculty of Sciences of GabesCite ErriadhUniversity of Gabes6079 GabesTunisia lnstitute of Catalysis and Petrochemistry CSICin MadridSpain Laboratory of nanomaterials Nanotechnology and Energy(L2NE)University of Tunis El ManarTunisia

This work investigated the influence of silver plasmon and reduced graphene oxide(r GO)on the photoelectrochemical performance(PEC)of Zn O thin films synthesized by the sol-gel *** physicochemical properties of the obtained photo-anodes were systematically studied by using several characterization *** x-ray diffraction analysis showed that all samples presented hexagonal wurtzite structure with a polycrystalline *** and energy dispersive x-ray(EDX)studies confirmed the existence of both Ag and r GO in Zn O:Ag/r GO thin *** estimated grain size obtained from scanning electron microscopy(SEm)analysis decreased with Ag doping,then increased to a maximum value after r GO *** UV-vis transmission spectra of the as-prepared Zn O:Ag and Zn O:Ag/r GO thin films have shown a reduction in the visible range with a redshift at the absorption *** bandgaps were estimated to be around 3.17 e V,2.7 e V,and 2.52 e V for Zn O,Zn O:Ag,and Zn O:Ag/r GO,***,the electrical measurements revealed that the charge exch.nge processes were enhanced at the Zn O:Ag/r GO/electrolyte interface,accompanied by an increase in the(PEC)performance compared to Zn O and Zn O:Ag ***,the photocurrent density of Zn O:Ag/r GO(0.2 m A·cm^(-2)) was around 4 and 2.22 times higher than photo-anodes based on undoped Zn O(0.05 m A·cm^(-2)) and Zn O:Ag(0.09 m A·cm^(-2)),***,from the flat band potential and donor density,deduced from the mott-Schottky,it was clear that all the samples were n-type semiconductors with the highest carrier density for the Zn O:Ag/r GO photo-anode.

关键词： zinc oxide reduced graphene oxide silver doping sol-gel photoelectrochemical performance

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Synthesis and characterization of La ni_xCo_(1–x)O_3: Role of microstructure on magnetic properties

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Journal of Rare Earths 2015年第3期33卷 277-281页

作者： L.chávez-Guerrero B.medina-Lott R.F.Cienfuegos m.A.Garza-navarro R.n.Vannier A.Ringuedé m. Hinojosa m.Cassir Universidad Autónoma de nuevo León FIME. Cd. Universitaria San Nicolás de los Garza México C.P. 66450 México Laboratoired’Electrochimie et de chimie Analytique UMR 7575 CNRS Chimie Paris Tech ENSCP 11 rue Pierre et Marie Curie F-75231 Paris Cedex 05 France Centro de Innovación Investigación y Desarrollo en Ingeniería y Tecnología PIIT Monterrey México Unité de Catalyse et de chimie du Solide UMR 8181 CNRS Villeneuve d’Ascq France

Perovskite-type structures with the composition La ni x Co1–x O3（x=0.3, 0.5, 0.7） were synthesized by a modified sol-gel method. Using transitional metal elements on the lanthanum base perovskites, properties could be tuned by doping the structure. Thermogravimetric analysis（TGA） evidenced a temperature of 350 °C as the start point of the perovskite-phase formation. Scanning electron microscopy（SEm） images showed the microstructure ch.nges（grain size） of the cobalt-doped perovskite due to composition. In addition, it was shown that magnetic properties of the samples were dependent of cobalt content; experimental results pointed to the existence of disordered spins interactions, which were more evident with the decrease of cobalt content and the existence of ferromagnetic coupling among spins of the samples. These results showed the feasibility of producing a family of compounds with the desired properties, manipulating composition and therefore the microstructure.

关键词： Co-doped perovskite microstructural control modified sol-gel ferromagnetic rare earths

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Systematic Study of nanocrystalline Plasma Electrolytic nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

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Journal of materials Science & Technology 2007年第5期23卷 665-671页

作者： m.Aliofkhazraei P.Taheri A.Sabour Rouhaghdam ch.Dehghanian materials Engineering Department Faculty of EngineeringTarbiat Modares UniversityTehranIran materials Engineering Department Faculty of EngineeringTehran UniversityTehranIran

A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment （DOE） technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating processes factors. The experimental design consisted of four factors （Urea concentration, electrical conductivity of electrolyte, voltage and duration of process）, each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise （S/n） ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance （AnOVA）. The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

关键词： nanocrystalline plasma electrolytic nitrocarburising 316L austenitic stainlesssteel Corrosion resistance Potentiodynamic polarization Analysis of variance

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