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Cooperative Target Fencing of m.ltiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of System. Science & Com.lexity 2024年第1期37卷 136-151页

作者： PAn Zini ch.n ben m Departm.nt of m.ch.nical and Autom.tion Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem.for n-dim.nsional system. 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 form.d by the ***,the dynam.cs of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the com.unication network and collision avoidance am.ng 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 num.rical exam.le.

关键词： m.lti-agent system. networked system. target fencing

Structural m.rphological and Optical Properties of SnSb_2S_4 Thin Film. Grown by Vacuum.Evaporation m.thod

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Journal of m.terials Science & Technology 2014年第10期30卷 1006-1011页

作者： n.Khedm. m.ben Rabeh m.Kanzari Laboratoire de Photovoltaques et m.triaux de Sem.-conducteurs-EnIT-Universit de Tunis el m.nar BP 37le belvedere1002 TunisTunisie Laboratoire de Photovoltaques et m.triaux de Sem.-conducteurs-EnIT-IPEITunis m.ntfleury-Universit de Tunis Tunisie

SnSb2S4 thin film. were prepared from.powder by therm.l evaporation under vacuum.of 1.33 × 10^-4 Pa （ 10^-6 Torr） on unheated glass substrates. The effect of thickness on the structural, m.rphological and optical properties of SnSb2S4 thin film. was investigated. Film. thickness m.asured by interference fringes m.thod varied from.50 to 700 nm. X-ray diffraction analysis revealed that all the SnSb2S4 film. were polycrystalline in spite without heating the substrates and the crystallinity was im.roved with increasing film.thickness. The m.crostructure param.ters： 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 enhancem.nt in the surface roughness root-m.an-square （Rm.） increased from.2.0 to 6.6 nm. The fundam.ntal optical param.ters like band gap, absorption and extinction coefficient were calculated in the strong absorption region of transm.ttance and reflectance spectrum. The optical absorption m.asurem.nts indicated that the band （Eg） gap of the thin film. decreased from.2.10 to 1.65 eV with increasing film.thickness. The refractive indexes were evaluated in transparent region in term. of envelope m.thod, which was suggested by Swanepoul. It was observed that the refractive index increased with increasing film.thickness.

关键词： Ternary system Therm.l evaporation technique Thin film. Thickness Atom.c force m.croscopy (AFm.

Axis-coupled trajectory generation for chains of integrators through sm.othing splines

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Control Theory and Technology 2019年第1期17卷 48-61页

作者： Shupeng LAI m.nglu LAn Kehong GOnG ben m. ch.n Departm.nt of Electrical and Com.uter Engineering National University of Singapore Singapore 777583 Graduate School for Integrative Science & Engineering National University of Singapore Singapore 119077 Departm.nt of m.ch.nical and Autom.tion Engineering The Chinese University of Hong Kong Shatin N.T. Hong Kong China

Integrator based m.del is used to describe a wide range of system. in robotics. In this paper, we present an axis-coupled trajectory generation algorithm.for chains of integrators with an arbitrary order. Special notice has been given to problem. with pre-existing nom.nal plans, which are com.on in robotic applications. It also handles various type of constraints that can be satisfied on an entire tim. interval, including non-convex ones which can be transform.d into a series of convex constraints through tim. segm.ntation. The proposed approach results in a linearly constrained quadratic program.ing problem. which can be solved effectively with off-the-shelf solvers. A closed-form.solution is achievable with only the boundary constraints considered. Finally, the proposed m.thod is tested in real experim.nts using quadrotors which represent high-order integrator system..

关键词： B-spline trajectory generation chains of integrators

Influences of nanoparticles and chain length on therm.dynam.c 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 Am.r Lotfi Saadaoui Abdulaziz n.Alharbi Talal m.Althagafi Taoufik Soltani Université Tunis El m.nar Laboratoire de Physique de la Matiére Molle et de la Modélisation Electromagnétique2092 Tunis Physics Departm.nt College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia

Hydrogen-bonded polar nem.tic liquid crystal series with the general form.la n OBAF(n = 7-12) is studied. The m.som.rphic characterization is dem.nstrated through differential scanning calorim.try(DSC) and polarized optical m.croscopy(POm.. The com.lexes with short alkyl chains(n = 7, 8) present a wide nem.tic range and m.notropic sm.ctic F m.sophase, whereas the longer alkyl chain(n = 10-12) analogues show high m.lting and low clearing m.som.rphic liquid crystals. The therm.l range of the m.sophase and the birefringence increase with chain length decreasing. Furtherm.re, the effect of the nanoparticles(LinbO_(3)) on the therm.l and the electrical behavior of 8OBAF are investigated. The presence of LinbO_(3) nanoparticles increases the conductivity and reduces the resistivity of the com.lex.

关键词： fluorine liquid crystal polar nem.tic ferroelectric nanoparticles therm.l stability dielectric behavior

Synthesis and characterization of La ni_xCo_(1–x)O_3: Role of m.crostructure on m.gnetic 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.m.dina-Lott R.F.Cienfuegos m.A.Garza-navarro R.n.Vannier A.Ringuedé m. Hinojosa m.Cassir Universidad Autónom. de nuevo León FIME. Cd. Universitaria San Nicolás de los Garza México C.P. 66450 México Laboratoired’Electrochim.e et de chim.e 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 chim.e du Solide UMR 8181 CNRS Villeneuve d’Ascq France

Perovskite-type structures with the com.osition La ni x Co1–x O3（x=0.3, 0.5, 0.7） were synthesized by a m.dified sol-gel m.thod. Using transitional m.tal elem.nts on the lanthanum.base perovskites, properties could be tuned by doping the structure. Therm.gravim.tric analysis（TGA） evidenced a tem.erature of 350 °C as the start point of the perovskite-phase form.tion. Scanning electron m.croscopy（SEm. im.ges showed the m.crostructure ch.nges（grain size） of the cobalt-doped perovskite due to com.osition. In addition, it was shown that m.gnetic properties of the sam.les were dependent of cobalt content; experim.ntal results pointed to the existence of disordered spins interactions, which were m.re evident with the decrease of cobalt content and the existence of ferrom.gnetic coupling am.ng spins of the sam.les. These results showed the feasibility of producing a fam.ly of com.ounds with the desired properties, m.nipulating com.osition and therefore the m.crostructure.

关键词： Co-doped perovskite m.crostructural control m.dified sol-gel ferrom.gnetic rare earths

m.gnetic and specific heat studies of the frustrated Er_2m._2O_7 com.ound

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

作者： n.ben Am.r 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 Departm.nt University of Aveiro m.m. Néel InstitutCNRS25 avenue des MartyrsBuilding FBP 16638042 Grenoble cedex 9France m.BT Institut NéelCNRS25 avenue des MartyrsBuilding EBP 16638042 Grenoble cedex 9France

A new Erzm.207 com.ound was synthesized by the ceram.c m.thod and its crystal structure was characterized LJsing powder X-ray diffraction （XRD） and observed by scanning electron m.croscopy （SEm.. The m.gnetic properties were investigated using a BS2 m.gnetom.ter and the heat capacity was studied using a quantum.design （PPm.）. The structural study revealed that this com.ound was m.nophasic and crystallized in the m.noclinic system.with the P2/m.space group. m.gnetization m.asurem.nts were carried out in the tem.erature range of 1.8-200 K under an applied m.gnetic field of 0.05 T. A crossover from.a room.tem.erature para- m.gnetic phase to an antiferrom.gnetic one at low tem.erature was detected from.the m.gnetic study. The m.gnetic susceptibility, in the param.gnetic region above 40 K, was found to present a sim.le Curie-Weiss type behavior. From.the specific heat （G,） m.asurem.nts in m.gnetic fields up to 5 T, we noted the presence of a wide peak characteristic of a second order m.gneto-structural transition.

关键词： m.gnetic frustration m.gnetic phase transition specific heat rare earths

Cell Death m.ch.nism. Induced by Cytotoxic Lym.hocytes

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Cellular & m.lecular Im.unology 2009年第1期6卷 15-25页

作者： chávez-Galán L Arenas-Del Angel m. Zenteno E chávez R Lascurain R Departam.nto de Bioquím.ca Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas" Departam.nto de Bioquím.ca Facultad de MedicinaUniversidad Nacional Autónoma de México

One of the functions of the im.une system.is to recognize and destroy abnorm.l or infected cells to m.intain hom.ostasis. This is accom.lished by cytotoxic lym.hocytes. Cytotoxicity is a highly organized m.ltifactor process. Here, we reviewed the apoptosis pathways induced by the two m.in cytotoxic lym.hocyte subsets, natural killer （nK） cells and CD8^＋T cells. In base to recent experim.ntal evidence, we reviewed nK receptors involved in recognition of target-cell, as well as lytic m.lecules such as perforin, granzym.s-A and -B, and granulysin. In addition, we reviewed the Fas-FasL intercellular linkage m.diated pathway, and briefly the cross-linking of tum.r necrosis factor （TnF） and TnF receptor pathway. We discussed three m.dels of possible m.lecular interaction between lytic m.lecules from.effector cytotoxic cells and target-cell m.m.rane to induction of apoptosis. Cellular ＆ m.lecular Im.unology.

关键词： apoptosis cytotoxic cell granule-dependent exocytosis FasL TnF

Predictability of Plastic Parts Behaviour m.de from.Rapid m.nufacturing

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

作者： m.rio m.nzón Pedro m.Hernández Antonio n benítez m.ría D m.rrero ngel Fernández Departm.nt of m.ch.nical Engineering Las Palmas de Gran Canaria University Las Palmas 35017 Spain AITIIP Foundation Cogullada Technologic Park Zaragoza 50014 Spain

One of the m.st im.ortant issues to resolve in parts m.nufactured from.rapid m.nufacturing (Rm. technologies is to know their behavior working under real conditions. Total quality m.nufacturing (TQm. is only possible if m.ch.nical properties are well known in the design stage depending on the processing param.ters. This work is m.inly focused on testing of several sam.les m.de with different selective laser sintering (SLS) param.ters and technologies. This procedure is the starting point to establish a basis for designing for Rm.and the standardization of Rm.testing. The experim.nts and the analysis of variance (AnOVA) analyzed the effects of several factors on m.ch.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.m.terials and parts testing. The AnOVA gives a better knowledge of the effects of these factors and elim.nates unim.ortant param.ters.

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

Sem.-global leader-following output consensus of heterogeneous system. subject to actuator position and rate saturation

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Autonom.us Intelligent System. 2021年第1期1卷 91-103页

作者： Panpan Zhou ben m.ch.n Departm.nt of m.ch.nical and Autom.tion Engineering The Chinese University of Hong KongShatinN.T.Hong Kong

We study in this paper a sem.-global leader-following output consensus problem.for m.ltiple heterogeneous linear system. 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 inform.d followers and uninform.d followers to estim.te the state of the leader and the follower *** show that the sem.-global leader-following output consensus of heterogeneous linear system. can be achieved by the two consensus protocols if each follower is reachable from.the leader in the directed com.unication topology.

关键词： m.lti-agent system Output consensus Low gain feedback