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共沉淀法制备Ho掺杂srBi_2Nb_2O_9的结构及介电性能研究（英文）

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Science China Materials 2016年第11期59卷 921-926页

作者： Mohamed Afqir Amina Tachafine didier fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mohamed Daoud Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakechMaroc Unitéde Dynamique et Structure des Matériaux Moléculaires Universitédu Littoral Côte d’OpaleCalaisFrance

本文报道了一种共沉淀法制备Ho掺杂SBN(SrBi_(2-x)Ho_xNb_2O_9:x=0和0.4),并利用X射线衍射、红外光谱和电学测试对其进行表征.结果表明,Ho掺杂SBN在较高频下具有低损耗和稳定的介电常数.因此这种材料非常适用于非易失FeRAM存储器的应用.

关键词： Co-precipitation XRD FTIR Dielectric properties

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Synthesis, Structural and Dielectric Properties of SrBi_1.8Ce_0.2Ta₂O₉

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Open Journal of Physical Chemistry 2016年第2期6卷 42-47页

作者： Mohamed Afqir Amina Tachafine didier fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mohamed Daoud Equipe Sciences des Matériaux Inorganiques et Leurs Applications Faculté des Sciences Semlalia Université Cadi Ayyad Marrakech Maroc Unité de Dynamique et Structure des Matériaux Moléculaires Université du Littoral Cote d’Opale Calais France

This Ce-doped strontium bismuth tantalate SrBi1.8Ce0.2Ta2O9 was prepared by solid-state reaction. X-ray diffraction was used to determine the crystal structure of the powders. The Raman spectrum of SrBi1.8Ce0.2Ta2O9 sample was measured to confirm X-ray diffraction result. The microstructure of ceramic was observed by Scanning Electron Microscope (SEM). The Temperature dependence of the dielectric properties of ceramic was investigated from the room temperature to 400°C.

关键词： Aurivillius Solid-State Electron Microscopy Raman Dielectric Properties Electrical Conductivity

Structural correlation and chemistry of molten NaF-ScF3 with dissolved metal aluminium:TG/DTA,XRD,NMR and molecular dynamics simulations

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Rare Metals 2024年第7期43卷 3356-3369页

作者： Aydar Rakhmatullin Franti?ek ?imko didier Zanghi Zuzana Netriová Ilya B.Polovov Ayrat Dimiev Konstantin V.Maksimtsev Catherine Bessada Michal Korenko Conditions Extrêmes et Materiaux:Haute Température et Irradiation CEMHTIUPR 3079-CNRS Univ Orleans Department of Molten Systems Institute of Inorganic ChemistrySlovak Academy of Sciences Centre of Excellence for Advanced Materials Application-CEMEA Slovak Academy of Sciences Department of Rare Metals and Nanomaterials Institute of Physics and TechnologyUral Federal University Alexander Butlerov Institute of Chemistry Kazan Federal University

For the first time,the mechanism of metal aluminum dissolution in NaF-ScF3eutectic melts and the chemical interaction between the constituents of this mixture have been thoroughly studied by a combination of differential thermal analysis（DTA）,high temperature and solid-state nuclear magnetic resonance（NMR）,and X-ray diffraction（XRD） coupled with the molecular dynamic *** formation of an insoluble Al3Sc alloy in molten（NaF-ScF3）eutsystem was proven,and the chemical mechanism of this aluminothermic Al3Sc alloy production was *** ex situ examinations bring to light the formation of NaScF4and solid solution of Na3（Al,Sc）F6in cooled *** molecular dynamics calculations of the bath allow us to construct the structural model and to predict viscosity,density and electrical conductivity of the reagent melt to help to optimize the conditions of the alloy synthesis.

关键词： Scandium Alloy Molten salts NMR Molecular dynamics

Design of bifunctional single-atom catalysts NiSA/ZIF-300 for CO_(2) conversion by ligand regulation strategy

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Nano Research 2024年第5期17卷 3827-3834页

作者： Wengang Fu Yapei Yun Hongting Sheng Xiaokang Liu Tao Ding Shuxian Hu Tao Yao Binghui Ge Yuanxin Du didier Astruc Manzhou Zhu Department of Chemistry and Centre for Atomic Engineering of Advanced Materials Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationCollege of Materials Science and EngineeringInstitutes of Physical Science and Information Technology and Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized MaterialsAnhui UniversityHefei 230601China Universitéde Bordeaux ISMUMR CNRS N°5255351 Cours de La Libération33405 Talence CedexFrance National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026China Department of Physics University of Science and Technology BeijingBeijing 100083China Anhui Tongyuan Environment Energy Saving Co. LtdHefei 230041China

Carbon-supported noble-metal-free single-atom catalysts(SACs)have aroused widespread interest due to their green chemistry aspects and excellent ***,we propose a“ligand regulation strategy”and achieve the successful fabrication of bifunctional SAC/MOF(MOF=metal-organic framework)nanocomposite(abbreviated NiSA/ZIF-300;ZIF=ZIF-8)with exceptional catalytic performance and *** designed NiSA/ZIF-300 has a planar interfacial structure with the Ni atom,involving one S and three N atoms bonded to Ni(Ⅱ),fabricated by controllable pyrolysis of volatile Ni-S *** CO_(2) cycloaddition to styrene epoxide,NiSA/ZIF-300 exhibits ultrahigh activity(turnover number(TON)=1.18×105;turnover frequency(TOF)=9830 molSC·mol_(Ni)^(-1)·h^(-1);SC=styrene carbonate)and durability at 70℃ under 1 atm CO_(2) pressure,which is much superior to Ni complex/ZIF,NiNP/ZIF-300,and most reported *** study offers a simple method of bifunctional SAC/MOF nanocomposite fabrication and usage,and provides guidance for the precise design of additional original SACs with unique catalytic properties.

关键词： single atom catalyst bifunctional CO_(2)conversion cycloaddition

Organizational Resilience:A Key Factor for Business Survival and Value Creation-A Secondary Publication

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Proceedings of Business and Economic Studies 2024年第2期7卷 245-253页

作者： Josédidier Váquiro Capera The University Foundation of the Andean Region PereiraColombia

The lodging and restaurant services sector in the city of Pereira presents complex situations generated by the turbulence of the new business *** that survive the new challenges and those recently established require strategies that allow them to extend their life ***,the study aims to identify how to apply resilience and management disciplines in a tool that allows companies in the sector under study to sufficiently face situations of high *** this objective requires knowing the causes of the short life span of many companies,identifying how surviving companies articulate management disciplines with their strategic objectives,and analyzing the possibility of formulating an organizational model based on resilience as a *** methodology applied was *** sample was simply random;23 companies were analyzed through structured interviews and participant *** the most significant results:the deficient application of management disciplines was identified as an important cause of company closures;the level of acceptance to implement the practice of resilience and management disciplines in companies;and the way to apply resilience and management disciplines in an instrument that builds *** was concluded that an organizational model should be formulated where resilience and management disciplines are applied to face times of crisis.

关键词： Resilience Financial management Risk management Information management Knowledge management

Erratum to:Effect of the synthesis route on the structural and dielectric properties of SrBi1.8Y0.2Nb2O9 ceramics

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1568-1568页

作者： Mohamed Afqir Amina Tachafine didier fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mustapha El Hammioui Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakech40000Maroc Unitéde Dynamique et Structure des Matériaux Moléculaires Universitédu Littoral-Côte d’OpaleCalais62100France Laboratoire de recherche sur la réactivitédes matériaux et l’optimisation des procédés Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakech40000Maroc

The original version of this article unfortunately contained a mistake. In the Table 1, the values of volume are not correct.

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Variations in Soil Organic Matter Content in Cultivated and Uncultivated Calcareous Soils from the Mediterranean Island of Malta after 15 Years of Cultivation

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Open Journal of Soil Science 2024年第4期14卷 210-226页

作者： Anthony T. Sacco Marcelle Agius Clara didier Institute of Earth Systems Division of Rural Sciences and Food Systems University of Malta Msida Malta É cole Nationale Sup&#233rieure Agronomique de Toulouse Auzeville-Tolosane France

The soils of Malta are calcareous and generally undeveloped. Organic matter (OM) in these soils is low and farmers are constantly urged to increase it. The objective of this study was to evaluate any temporal variation in soil OM after 15 years of cultivation, and determine whether soil series, soil depth, and cultivation influence variation. OM was determined in the topsoil and subsoil of 7 agricultural and 4 non-agricultural sites. The sites represented 7 different soil series that are present on the island. In sampling periods 1 (t = 0 years) and 2 (t =15 years), the OM content in the collective (all soil series) bulk (topsoil and subsoil) uncultivated soil was 3.9 % and 3.8 % respectively. This was significantly greater than that of the collective bulk cultivated soil (2.4% and 2.3%). The OM in the collective uncultivated topsoil was 5.4% and 5.2% in periods 1 and 2 and was significantly higher than that of the cultivated topsoil (2.5% in both periods). The OM content in the collective uncultivated subsoil was 2.3% and 2.5% in periods 1 and 2 respectively but only that measured in period 2 was significantly higher than that of the cultivated subsoil (2.2% in both periods). On an individual soil series basis, the OM in the uncultivated topsoils was significantly higher than that of their cultivated counterparts. The differences in the subsoils were not significant. Across the uncultivated soil series, OM was significantly higher in the topsoil than in the subsoil but in the cultivated soil series the differences between topsoil and subsoil were not significant. There was no significant difference in OM between the uncultivated soils of different series, but in the cultivated the OM content was higher in soils that were more mature. After 15 years, no significant change in OM occurred in both the collective cultivated and uncultivated bulk soils, the collective topsoil and subsoil, and in most of the individual series. The OM content of each soil series was also s

关键词： Soil Organic Carbon Agricultural Land Non-Agricultural Land Land Management

Fe_(3)O_(4)对黄铜矿在酸性硫酸铁溶液中铜溶解氧化还原反应的影响

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Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1965-1975页

作者： Kolela J NYEMBWE Elvis FOSSO-KANKEU Frans WAANDERS Martin MKANDAWIRE didier K NYEMBWE Bhekie B MAMBA Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversityPotchefstroomSouth Africa Department of Mining Engineering College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa Department of Metallurgy Faculty of Engineering and Built EnvironmentUniversity of JohannesburgDoornfonteinJohannesburgSouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada School of Mining Metallurgy and Chemical EngineeringFaculty of Engineering and the Built EnvironmentUniversity of JohannesburgJohannesburgSouth Africa Institute for Nanotechnology and Water Sustainability College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(... 详细信息

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(4))_(3)−H_(2)SO_(4)浸出剂中添加磁铁矿(Fe_(3)O_(4))对铜溶解速率的影响。结果表明,溶液pH值、电位和温度在溶解过程中起着关键作用。在pH 1.8、50℃和400 mV的条件下,Fe_(3)O_(4)−CuFeS_(2)混合体系中铜的回收率达到最大值(70%),而未添加Fe_(3)O_(4)时,CuFeS_(2)中铜的回收率较低(48%)。添加Fe_(3)O_(4)有助于维持较高的氧化还原值。添加Fe_(3)O_(4)还使活化能从79.04 kJ/mol降低到53.69 kJ/mol。这表明,当Fe_(3)O_(4)存在时,由于形成了更易溶解的中间体斑铜矿(Cu_(5)FeS_(4))和辉铜矿(Cu_(2)S),CuFeS_(2)更易被氧化。两种溶解过程都受到矿物表面的化学控制。此外,对浸出残渣的矿物学分析表明,当无Fe_(3)O_(4)存在时,作为表面钝化物的黄钾铁矾浓度较高。因此,添加Fe_(3)O_(4)减少了钝化层的形成,提升了铜的回收率。

关键词：黄铜矿溶解磁铁矿电偶钝化

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Physico-Chemical and Structural Assessment of Akono Riparian Forest Watershed, Tributary of the Nyong Basin (Centre-Cameroon) at Different Stages of Degradation

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Journal of Environmental Protection 2024年第5期15卷 552-571页

作者： Nwamo Roland didier Gordon Nwutih Ajonina Ndzougou Nkodo Colette Rose Tomedi Eyango Minette Department of Management of Aquatic Ecosystems Institute of Fisheries and Aquatic Sciences at Yabassi University of Douala Yabassi Cameroon Cameroon Wildlife Conservation Society Mangrove & Coastal Wetlands Research Centre Mouanko Cameroon Department of Aquaculture Institute of Fisheries and Aquatic Sciences at Yabassi University of Douala Yabassi Cameroon

Freshwater bodies are natural resources that should be exploited to the fullest, while maintaining the sustainability of ecosystems and ecosystem services which they support. Riparian forests are more important as they contain rivers which are vital sources of fresh water for local populations. However, the quality and quantity of water issued from the watershed depend on the structural state of these forests. The aim of this work was to assess the physico-chemical and structural state of the Akono gallery forest. To achieve this, fieldwork consisted of selecting six major streams of the watershed including Ndjolong, Menyeng adzap, Emomodo, Mvila, Negbe and Ossoé kobok. On each of these, two stations, one intact and one degraded, were marked by transects. The method involved measuring Hydrometric parameters (depth, length, width) of the stream and Physico-chemical parameters of water in the streams while dendrometric parameters were measured along 100 m-transects laid using the point-centred quarter method modified for water bodies to collect tree, shrub and palm variables such as trunk diameter, crown diameter and height. Macrophytes and species identification were carried out using standard botanical procedures. Results showed that, the majority of physico-chemical parameters measured differed significantly between intact and degraded stations (P Pentachletra mancrophylla, whereas on degraded sites, this index was low and characterized by the relative dominance of species Piptadeniastrum africanum. Sorensen’s index (0.56) and CFA showed that the different stands were homogeneous. We can affirm that the riparian forests of Akono watershed are towards a state of stability notwithstanding the perpetuation of anthropological actions.

关键词： Akono Gallery Forest Physico-Chemical Parameters Floristic Diversity Dendrometric Parameters