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Exploration and Mapping of Metalliferous Black Shales in the Saghro Temporary Subsidence Zones (Anti-Atlas, Morocco)

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Open Journal of Geology 2023年第7期13卷 740-762页

作者： Ali Bouayachi Saida Alikouss Zouhir Baroudi Youssef Zerhouni Lahcen Rakhis mohammed zouhair Assia Idrissi Mourad Essalhi Barzouk Abdelhafed Department of Geology Faculty of Sciences Ben M’Sik University Hassan II Casablanca Morocco MANAGEM Group 191 bd Med Zerktouni Twin Center Tour A. 20100 Casablanca Morocco Department of Geology Faculty of Sciences University Mohamed V Rabat Morocco Faculty of Sciences and Techniques University Molay Ismail Errachidia Morocco Faculty of Sciences Semlalia Caddi Ayyad University Marrakech Morocco

The Saghro massif constitutes a vast metallogenic province with numerous deposits and shows of base metals (lead, zinc, copper) and precious metals (gold and silver), besides various useful substances (talc, pyrophyllite, barite, fluorite). Silver/lead occurrences are concentrated along the Cryogenian Imiter series and moderately at Boumalne and Sidi Flah. Copper occupies the plutonic intrusions and intrusive rocks of the East-Central Saghro while barite deposits are widespread throughout the Cambrian cover of the East Saghro in contact with the Ediacaran basement. To justify this distribution, the new contributions of the cartography and the organic geochemistry of the black shales of Jbel Saghro have clearly shown the particularity of the Imiter black shales in terms of the richness in organic matter (TOC = 0.18%), the blackish color and the friability. The Boumalne and Sidi Flah groups present some similarities with the Imiter group, such as the sub-equatorial structuring, the friable pelites and the richness in organic matter (Boumalne TOC = 0.11% and SidiFlah TOC = 0.16%), which is a quite good show that requires to reinforce the exploration works. For Western Saghro in the Iknioun and Qalaa’t M’Gouna groups, the variations in the thickness of the volcanic cover show an irregular paleotopography with hard, greenish, organic-poor pelitic sediments (TOC = 0.01 to 0.04%). We can conclude that the formation of Imiter-type silver concentrations requires the combination of the sedimentological, the volcanic and structural factors. For Imiter-type silver these factors are: a fine pelitic and argillic casing deposited in a confined environment, a basic volcanism source of metals and other intermediate to acid generated by the hydrothermalism and heat, a convenable paleotopography and a network of fracturations to trap the mineralizations.

关键词： Saghro Metallic Shales Silver TOC Exploration Cryogenic Polymetallic Imiter

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Novel lead-free BCZT-based ceramic with thermally-stable recovered energy density and increased energy storage efficiency

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Journal of Materiomics 2022年第4期8卷 873-881页

作者： zouhair Hanani Soukaina Merselmiz M'barek Amjoud Daoud Mezzane mohammed Lahcini Jaafar Ghanbaja Matjaz Spreitzer Damjan Vengust Mimoun El Marssi Igor A.Luk'yanchuk Zdravko Kutnjak Brigita Rozic Mohamed Goune IMED-Lab Cadi Ayyad UniversityAvenue Abdelkrim El KhattabiP.B.549Marrakesh40000Morocco ICMCB University of Bordeaux87 Avenue Du Dr Albert SchweitzerPessac33600France Jozef Stefan Institute Jamova Cesta 39Ljubljana1000Slovenia LPMC University of Picardy Jules Verne33 Rue Saint LeuAmiens80039France mohammed VI Polytechnic University Lot 660-Hay Moulay RachidBen Guerir43150Morocco IJL University of Lorraine54000NancyFrance Department of Building Materials Kyiv National University of Construction and ArchitectureKyiv03680Ukraine

The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than adecade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-freecompounds, having comparable or even better performance has not yet been reached. In this road, thelead-free ceramics Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3) (BCZT), possessing excellent dielectric, ferroelectric, andpiezoelectric properties are regarded as serious candidates for the PZT replacement. Besides, nano-structuring BCZT is of paramount importance to enhance these functionalities even more. Here, BCZTmultipodes are designed by template-growth hydrothermal synthesis using hydrogen zirconate titanatenanowires. We demonstrate that the fabricated BCZT multipodes exhibit high dielectric permittivity of5300 with a temperature stability coefficient of ±5.9% between 20 and 140℃. A significant recoveredenergy density of 315.0 mJ/cm^(3) with high thermal stability and high energy storage efficiency of 87.4%,and enhanced large-signal piezoelectric coefficient d^(*)_(33) (310 pm/V) are found. Compared to the tradi-tional BCZT ceramics reported in the literature, relying on high-temperature processing, our sampleexhibits boosted energy storage parameters at a much lower temperature. These outcomes may offer anew strategy to tailor eco-responsible relaxor ferroelectrics toward superior energy storage performancefor ceramic capacitor applications.

关键词： Lead-free ceramics Low temperature Piezoelectric Thermal stability Energy storage Nanostructuration

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Wireless Mobile Evolution to 4G Network

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Wireless Sensor Network 2010年第4期2卷 309-317页

作者： mohammed Jaloun zouhair Guennoun 不详

In this paper, we give an overview of the evolution of wireless mobiles starting from the first generation which is the analogue system started in 1980’s, and passing through the 2G technologies which are all digital networks and GSM is the most popular network. 2.5G networks will introduce the packet notion on the existing 2G networks and 3G will bring the quality of service as new perspective for the 3G partnership projet 3GPP and 3GPP2. However, high demand on data speed has pushed the operators to looking for 3.5G system. 3.99G networks are defined as long-term evolution for the existing 3G network and it will be based on OFDM and MIMO technologies. 4G networks was not yet defined, but requirement is to support heterogeneous networks at 100 Mbps mobility data speed.

关键词： 4G OFDM MIMO

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Enhanced dielectric and electrocaloric properties in lead-free rod-like BCZT ceramics

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Journal of Advanced Ceramics 2020年第2期9卷 210-219页

作者： zouhair HANANI Soukaina MERSELMIZ Abdelaadim DANINE Nicolas STEIN Daoud MEZZANE M’barek AMJOUD mohammed LAHCINI Yaovi GAGOU Matjaz SPREITZER Damjan VENGUST Zdravko KUTNJAK Mimoun El MARSSI Igor ALUK'YANCHUK Mohamed GOUNE IMED-Lab Cadi Ayyad UniversityMarrakesh 40000Morocco ICMCB University of 1.BordeauxPessac 33600France IJL University of LorraineNancy 54000France UM6P Ben Guerir 43150Morocco LPMC University of Picardy Jules VerneAmiens 80039France Jozef Stefan Institute Ljubljana 1000Slovenia Physics Faculty Southern Federal UniversityRostov-on-Don 344090Russia

Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological changes on dielectric and ferroelectric properties in lead-free BCZT ceramics,researchers have mostly focused on the influence of spherical grain shape *** this study,BCZT ceramics with rod-like grains and aspect ratio of about 10 were synthesized by surfactant-assisted solvothermal route.X-ray diffraction(XRD)and selected area electron diffraction(SAED)performed at room temperature confirm the crystallization of pure perovskite with tetragonal *** electron microscopy(SEM)image showed that BCZT ceramics have kept the 1D rod-like grains with an average aspect ratio of about ***-like BCZT ceramics exhibit enhanced dielectric ferroelectric(εr=11,906,tanδ=0.014,Pr=6.01μC/cm^2,and Ec=2.46 kV/cm),and electrocaloric properties(ΔT=0.492 K andz=0.289(K×mm)/kV at 17 kV/cm)with respect to spherical BCZT ***,rod-like BCZT lead-free ceramics have good potential to be used in solid-state refrigeration technology.

关键词： lead-free Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT) rod-like Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT) dielectric ferroelectric electrocaloric effect

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Solutions Comparison towards Voice Services Implementation for Operators Starting LTE Deployment

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Communications and Network 2012年第2期4卷 122-128页

作者： Youness Jouihri zouhair Guennoun Laboratoire d’ Electronique et de Communications—LEC Ecole Mohammadia d’ Ingénieurs—EMI Université Mohammed V-Agdal—UM5A Rabat Morocco

The continuity of voice services, for many operators planning to start their LTE network, is one of the key requirements to cover back the cost of this expensive network. In this paper, we discuss and compare the possible solutions to add voice services on an LTE network dedicated mainly for high-speed data transfer. By comparing advantages and inconvenient of the existing approaches, we conclude that the selection of the One Voice approach is obvious, especially for operators starting LTE deployments, the One Voice approach has the support of all the famous operators and vendors. Selecting the One Voice approach as a first alternative was evident, but the choice of CSFB as a mid-term solution or backup solution from many operators was not clear. As a key lesson can be learned from the existing technologies, CDMA and GSM, where the type of handset was one of the major factors of the GSM success;we prove in this paper that VOLGA approach is better than CSFB for many reasons: The VOLGA approach uses less complex and less expensive handset while it gives more comfortable user experience compared to CSFB approach, so operators should take into consideration these two points before selecting the second alternative.

关键词： Voice over LTE One Voice VOLGA IMS SIP CSFB SRVCC

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Privacy Preserving Scheme for Location-Based Services

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Journal of Information Security 2012年第2期3卷 105-112页

作者： Youssef Gahi Mouhcine Guennoun zouhair Guennoun Khalil El-Khatib Laboratoire d’Electronique et de Communications—LEC Ecole Mohammadia d’Ingénieurs—EMI Université Mohammed V-Agdal—UM5A. BP Rabat Morocco University of Ontario Institute of Technology Oshawa Canada

Homomorphic encryption schemes make it possible to perform arithmetic operations, like additions and multiplications, over encrypted values. This capability provides enhanced protection for data and offers new research directions, including blind data processing. Using homomorphic encryption schemes, a Location-Based Service (LBS) can process encrypted inputs to retrieve encrypted location-related information. The retrieved encrypted data can only be decrypted by the user who requested the data. The technology still faces two main challenges: the encountered processing time and the upper limit imposed on the allowed number of operations. However, the protection of users’ privacy achieved through this technology makes it attractive for more research and enhancing. In this paper we use homomorphic encryption schemes to build a fully secure system that allows users to benefit from location-based services while preserving the confidentiality and integrity of their data. Our novel system consists of search circuits that allow an executor (i.e. LBS server) to receive encrypted inputs/requests and then perform a blind search to retrieve encrypted records that match the selection criterion. A querier can send the user’s position and the service type he/she is looking for, in encrypted form, to a server and then the server would respond to the request without any knowledge of the contents of the request and the retrieved records. We further propose a prototype that improves the practicality of our system.

关键词： Privacy Location Based Services Homomorphic Encryption

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Adaptive Switching between Space-Time and Space-Frequency Block Coded OFDM Systems in Rayleigh Fading Channel

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International Journal of Communications, Network and System Sciences 2013年第6期6卷 316-323页

作者： My Abdelkader Youssefi Nawal Bounouader zouhair Guennoun Jamal El Abbadi Laboratoire d’Electronique et de Communications (LEC) Ecole Mohammedia d’ingénieurs (EMI) Université Mohammed V Agdal (UM5A) Rabat Morocco

This work explores the performances of Space-Time and Space Frequency Coded Orthogonal Frequency Division Multiplexing (OFDM) with simple two branches transmit diversity scheme. The combination of multiple-antenna and orthogonal frequency division multiplexing (OFDM) provides reliable communications over frequency selective fading channels. We focus on the application of space-time block codes (STBC) and space-frequency block codes (SFBC) in OFDM systems over time-varying and frequency-selective channels. SFBC transmitter shows superior performance in fast varying channels while STBC shows better performance in frequency selective channels. A switching technique is presented that selects an appropriate transmission scheme between the STBC and SFBC assuming Rayleigh fading model.

关键词： OFDM MIMO Rayleigh Fading Channel STBC SFBC

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Does Obesity Affect Early Results after Coronary Artery Bypass Grafting?

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World Journal of Cardiovascular Surgery 2017年第10期7卷 119-129页

作者： Mahdi Aithoussa Noureddine Atmani Anis Seghrouchni Abdessamad Abdou Younes Moutakiallah Mehdi Bamous Siham Bellouize Fouad Nya zouhair Lakhal Abdedaim Hatim Ghadbane Youssef Elbekkali Abdelatif Boulahya Department of Cardiovascular Surgery Mohammed V Military Teaching Hospital Mohammed V University Souissi Rabat Morocco Department of Cardiology Mohammed V Military Teaching Hospital Mohammed V University Souissi Rabat Morocco

Background: The aim of this study was to quantify the effect of obesity on early results after coronary artery bypass grafting (CABG). Methods: A retrospective cohort study of patients underwent isolated CABG from January 2000 through December 2012 was conducted. 586 patients were classified into two groups: Obese (n = 100) BMI ≥ 30 kg/m2 and non-obese (n = 486) BMI ≤ 30kg/m2. Results: The obese patients included more women (p 0.01), hypertensives (p = 0.01) and dyslipidemics (p = 0001). The CPB, aortic champ times and number of bypass graft were similar between the groups (p = 0.35, p = 0.51 and p = 0.59 respectively). Also the composite of in-hospital mortality and postoperative complication didn’t differ between the groups. The incidence of perioperative myocardial infarction, and need for inotropic drugs or IABP were significantly less in obese patients (p = 0.028, p = 0.031 and p 0.01 respectively). Conclusions: The current study showed that obesity is not a risk factor of adverse events after CABG and continuous to give another aspect of the “obesity paradox”.

关键词： Obesity Coronary Artery Bypass Grafting Morbidity Mortality

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