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Hourly and monthly variations in the surface activity patterns of Hemilepistus reaumurii in arid environments of Tunisia

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Journal of Arid Land 2018年第3期10卷 470-481页

作者： Anas AYARI Moez TOUIHRI Chedlia GHEMARI karima nasri-ammar Research Unit of Bio-Ecology and Evolutive Systematics Faculty of Sciences of Tunis University of Tunis El Manar

Life in desert ecosystems drives animals to adapt their surface locomotor activity according to environmental conditions. In this study, the hourly and monthly variations in the surface activity patterns of the terrestrial crustacean Hemilepistus reaumurii were investigated. The surface activity of H. reaumurii at the population scale was observed by collecting the hourly active individuals from the sunrise to the sunset of the studied day in each month of 2013 in the Bchachma locality, Tunisia. The collected active individuals were put in perspex boxes（on which we labeled the hourly time interval in which the individuals were collected） in the field and then transported to the laboratory for analysis. Individuals were counted, sexed, and measured in the laboratory. Despite desert conditions in the studied site, H. reaumurii was characterized by a diurnal surface activity, showing a bimodal pattern during the warm months（i.e., May to October）. However, it exhibited a unimodal surface activity pattern in the cold months（i.e., February, March, and November）. The surface activity was significantly correlated with sunrise and sunset. Moreover, a significant quadratic effect of temperature on the surface activity of H. reaumurii was observed. Furthermore, the study showed that the most important surface activity was recorded in March. The daily exploitation of the temporal niches was significantly different as a function of months. The body size of males was larger than that of females, and the body size of active individuals changed with months. All these behavioural changes in the surface activity represent an adaptive strategy of life in the arid environment.

关键词： diurnal activity variation pattern aboveground activity desert isopod temporal niche Hemilepistus reaumurii Tunisia

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Improvement of mobility edge model by using new density of states with exponential tail for organic diode

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Chinese Physics B 2015年第4期24卷 360-365页

作者： Muhammad ammar Khan 孙久勋 School of Physical Electronics University of Electronic Science and Technology

The mobility edge （ME） model with single Gaussian density of states （DOS） is simplified based on the recent exper- imental results about the Einstein relationship. The free holes are treated as being non-degenerate, and the trapped holes are dealt with as being degenerate. This enables the integral for the trapped holes to be easily realized in a program. The J-V curves are obtained through solving drift-diffusion equations. When this model is applied to four organic diodes, an obvious deviation between theoretical curves and experimental data is observed. In order to solve this problem, a new DOS with exponential tall is proposed. The results show that the consistence between J-V curves and experimental data based on a new DOS is far better than that based on the Gaussian DOS. The variation of extracted mobility with temperature can be well described by the Arrhenius relationship.

关键词： organic diode potential barriers Einstein relationship

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Robustness of the New FDR Receiver to HDR UWB Systems in the Presence of Multi User Interference

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通讯和计算机（中英文版） 2012年第9期9卷 1045-1050页

作者： karima Ben Hamida El Abri ammar Bouallegue Syscoms Laboratory National Engineering School of Tunis Tunisia

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Wide-Angle Scanning Antennas for Millimeter-Wave 5G Applications

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Engineering 2022年第4期8卷 60-71页

作者： Raj Mittra Abdelkhalek nasri Ravi Kumar Arya Electrical and Computer Engineering University of Central FloridaOrlandoFL 32816USA Electrical and Computer Engineering Department Faculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Electronics and Communication Engineering National Institute of Technology DelhiDelhi 110040India

The fifth generation(5G)network communication systems operate in the millimeter waves and are expected to provide a much higher data rate in the multi-gigabit range,which is impossible to achieve using current wireless services,including the sub-6 GHz *** this work,we briefly review several existing designs of millimeter-wave phased arrays for 5G applications,beginning with the low-profile antenna array designs that either are fixed beam or scan the beam only in one *** then move on to array systems that offer two-dimensional(2D)scan capability,which is highly desirable for a majority of 5G ***,in the main body of the paper,we discuss two different strategies for designing scanning arrays,both of which circumvent the use of conventional phase shifters to achieve beam *** note that it is highly desirable to search for alternatives to conventional phase shifters in the millimeter-wave range because legacy phase shifters are both lossy and costly;furthermore,alternatives such as active phase shifters,which include radio frequency amplifiers,are both expensive and *** this backdrop,we propose two different antenna systems with potential for the desired 2D scan performance in the millimeter-wave *** first of these is a Luneburg lens,which is excited either by a 2D waveguide array or by a microstrip patch antenna array to realize 2D scan ***,for second design,we turn to phased-array designs in which the conventional phase shifter is replaced by switchable PIN diodes or varactor diodes,inserted between radiating slots in a waveguide to provide the desired phase shifts for ***,we discuss several approaches to enhance the gain of the array by modifying the conventional array *** describe novel techniques for realizing both one-dimensional(1D)and 2D scans by using a reconfigurable metasurface type of panels.

关键词： Luneburg lens Scanning arrays Millimeter-wave antennas Switchable phase shifters Reconfigurable metasurfaces

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Conduction properties of condensed lanthanum phosphates:La(PO_3)_3 and LaP_5O_(14)

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Journal of Rare Earths 2010年第3期28卷 321-328页

作者： Ines Hammas karima Horchani-Naifer Mokhtar Férid Research Unit of Rare Earth Materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia

Single crystals of LaP3O9·3H2O were prepared using a classical method of aqueous chemistry whereas those of the ultraphosphate LaP5O14 were obtained by flux *** treatment of LaP3O9·3H2O up to 700 °C allowed us to obtain the lanthanum polyphosphate La(PO3)*** conductivity as well as the vibrational study of the lanthanum ultraphosphate and polyphosphate were analysed in order to explain the mechanism of *** energies of 0.45 and 0.84 eV,deduced from the Arrhenius relation,were r...

关键词： condensed lanthanum phosphates electrical conductivity Grotthuss mechanism rare earths

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A critical review of intrusion detection systems in the internet of things:techniques,deployment strategy,validation strategy,attacks,public datasets and challenges

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Cybersecurity 2021年第1期4卷 251-277页

作者： Ansam Khraisat ammar Alazab Federation University Australia Federation University AustraliaBallaratAustralia

The Internet of Things(IoT)has been rapidly evolving towards making a greater impact on everyday life to large industrial ***,this has attracted the attention of cybercriminals who made IoT a target of malicious activities,opening the door to a possible attack on the end *** this end,Numerous IoT intrusion detection Systems(IDS)have been proposed in the literature to tackle attacks on the IoT ecosystem,which can be broadly classified based on detection technique,validation strategy,and deployment *** survey paper presents a comprehensive review of contemporary IoT IDS and an overview of techniques,deployment Strategy,validation strategy and datasets that are commonly applied for building *** also review how existing IoT IDS detect intrusive attacks and secure communications on the *** also presents the classification of IoT attacks and discusses future research challenges to counter such IoT attacks to make IoT more *** purposes help IoT security researchers by uniting,contrasting,and compiling scattered research ***,we provide a unique IoT IDS taxonomy,which sheds light on IoT IDS techniques,their advantages and disadvantages,IoT attacks that exploit IoT communication systems,corresponding advanced IDS and detection capabilities to detect IoT attacks.

关键词： Malware Intrusion detection system IoT Anomaly detection Machine learning Deep learning Internet of things Attacks IoT security

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Complex dynamics and bifurcation analysis for a Beverton-Holt population model with Allee effect

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International Journal of Biomathematics 2023年第7期16卷 165-196页

作者： karima Mokni Mohamed Ch-Chaoui MRI Laboratory FacultéPolydisciplinaire Khouribga Sultan Moulay Slimane University BP:145 Khouribga Principale25000Kingdom of Morocco

In this paper,we have derived a discrete evolutionary Beverton-Holt population *** model is built using evolutionary game theory methodology and takes into consideration the strong Allee effect related to predation *** have discussed the existence of the positive fixed point and examined its asymptotic ***,we demonstrated that the derived model exhibits Neimark-Sacker bifurcation when the maximal predator intensity is at lower *** chaotic behaviors are justified ***,to avoid these chaotic features and achieve asymptotic stability,we implement two chaos control methods.

关键词： Evolutionary game theory asymptotic stability Neimark-Sacker bifurcation chaos control

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Combustion synthesis and luminescence properties of LaPO4： Eu （5%）

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Journal of Rare Earths 2009年第2期27卷 182-186页

作者： Mounir Ferhi karima Horchani-Naifer Mokhtar Férid Research Unit of Rare Earth Materials National Research Center in Sciences of Materials B.P. 95 Hammam-Lif 2050 Tunisia

Rare earth doped materials are an important type of phosphors due to their excellent performance such as stability at high temperature and light emission covering the entire visible domain. The combustion synthesis at acid pH of the monoclinic LaPO4： Eu（5%） powders was described. A mixture of La（NO3）3·6H2O, EuCly6H2O and （NH4）2HPO4 was used as anion precursor and glycin as fuel. The synthesis was followed by structure, morphology characterisation and luminescent properties of the obtained compound. The room temperature emission measurements under ultraviolet excitation at 254 nm were made for the emission transition ^5D0→^7FJ of this phosphor. The CIE （Commission Intemationale de L＇Eclairage） chromatic coordinates, dominant wavelength and colour purity were determined and compared to other luminescent materials obtained by other methods.

关键词： rare earth phosphates combustion optical materials luminescence chromaticity

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Crystal structure and infrared spectrum of thallium holmium polyphosphate, TlHo(PO_3)_4

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Journal of Rare Earths 2008年第6期26卷 765-769页

作者： karima Horchani-Naifer Jaouher Amami Mokhtar Férid Unité de Recherches de Matériaux de Terres Rares Centre National de Recherches en Sciences des Matériaux

Crystals of thallium-holmium polyphosphate T1Ho（PO3）4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of T1Ho（PO3）4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions： a=1.02225（3） nm, b=0.88536（2） nm, c=1.09541（4） nm, β=105.888（1）°, V=0.95354（5） nm^3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1（F^2）=0.0442 and Rw（F^2）=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eightfold coordination. The structure of T1Ho（PO3）4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350--4000 cm^-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.

关键词： polyphosphate holmium crystal structure infrared spectroscopy rare earths

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Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode observer

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Frontiers in Energy 2020年第4期14卷 836-849页

作者： Abdelkarim ammar Amor BOUREK Abdelhamid BENAKCHA LGEB Laboratory Department of Electrical EngineeringUniversity of BiskraBiskraBP 145Algeria

This paper proposes a design of control and estimation strategy for induction motor based on the variable structure *** describes a coupling of sliding mode direct torque control(DTC)with sliding mode flux and speed *** algorithm uses direct torque control basics and the sliding mode approach.A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC draw・backs and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple *** sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation(SVM)*** second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation,and consequently,increase the reliability of the system and decrease the cost of using *** effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.

关键词： induction motor direct torque control(DTC) space vector modulation(SVM) sliding mode control(SMC) sliding mode observer(SMO) dS1104

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