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Geochemical and Petrological Insights into the Neoproterozoic Moumba Metabasites: Implications for Crustal Processes in the West Congo Belt (Republic of Congo)

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Journal of Geoscience and environment Protection 2024年第2期12卷 1-29页

作者： Ulrich Verne Matiaba-Bazika Nelson Lekeba Makamba Vicky Tendresse Télange Bouénitéla Nicy Carmelle Bazebizonza Tchiguina timothée miyouna Florent Boudzoumou Laboratory of Geosciences Faculty of Sciences and Technics Marien NGOUABI University Brazzaville Republic of Congo National Institute for Research in exact and Natural Sciences (IRSeN) Brazzaville Republic of Congo Geographid Research and Cartographic Production Center (CeRGeC) Brazzaville Republic of Congo

The West Congo Belt contains in its rocks of Neoproterozoic age from Nemba complex outcropping in the Moumba River. This West Congo belt is made up of a crustal segment of the Arcuaï-West Congo orogen which extends from southwest Gabon to the northeast of Angola. This study aims to constrain the geochemical signature Nemba complex of West Congo belt from the petrograhic and geochemical study on the whole rock. The petrographic data from this study show the Moumba metabasites are made up of amphibolites, metagabbros, epidotites and greenschists interstratified in the eburnean metasediments and affected by mesozonal to epizonal metamorphism characterized by the retromorphosis of intermediate amphibolite facies minerals into greenschist facies. Whole-rock geochemical data indicate that these metabasites are continental flood basalts (CFB) of basic nature and transitional affinity emplaced in intraplate context. These continental flood basalts are generated from magma originating from a significantly enriched shallow mantle plume and this magma then contaminated by the continental crust during their ascent. The reconstruction of tectonic signature suggests that West Congo belt would result from closure of an ocean basin with subduction phenomena. This collision would be marked by the establishment of ophiolite complex. We show that this model is incompatible with the CFB nature of metabasites and the orogenic evolution of Neoproterozoic. It does not seem that we can evoke a genetic link with a subduction of oceanic crust, because the paleogeography of Neoproterozoic (Rodinia) is marked by intracontinental rifts linked to opening of Rodinia. We therefore suggest the non-existence of ophiolitic complex in western Congo belt and reject the collisional model published by certain authors. We confirm the currently available intracontinental orogen model.

关键词： Mayombe Metabasites Moumba Mantle Plume Continental Rifting Basalts Flood Continental

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Characterization of Gold Bearing Placers and Associated Minerals in the elogo Region (North-West Congo Republic)

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Open Journal of Geology 2023年第5期13卷 287-305页

作者： Noël Watha-Ndoudy Prince espoire Wamene Okoumel timothée miyouna Renaud Hermann Assouka Mpika eddy Guembou Massala Guichel Souaty Mibantsa Kester Mayenga Joseph Victor Hell Boniface Kankeu Florent Boudzoumou Laboratory of Geosciences Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo National Institute of Forestry Research (IRF) Brazzaville Congo Gold Mines and Quarries of Congo MAC-CONGO Brazzaville Congo Institute of Geological and Mining Research (IRGM) Yaoundé Cameroun

The elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The goal of this study is to contribute to the exploration of the primary gold deposit in the elogo Region (North-West of Congo Republic). The methodology consisted of characterization of placers deposits by their lithology, mineralogy and the gold grains shape, in order to constrain the source of gold with the respect to the local geology. The results obtained show that alluviums are polygenic and yields seventeen mineral species composed of zircon, olivine, magnetite, ilmenite, gold, garnet, rutile, coltan, cassiterite, monazite, apatite, amphibole, tourmaline, pyrite, limonite, chromite, and amphibole. The morphoscopy of gold grain shows single grains and grains with quartz inclusions that suggest their relationship with quartz veins. The gold grains are flattened, sub-flattened, and rounded. The northern region of elogo characterized by a dominance of coarser quartz-included gold grains indicates a proximal proparte origin (less than 50 m), while the southern region, showing less coarse and more evolved grains with choc marks, appears to be associated with a distal pro-parte origin (more than 300 m). The multivariate statistical analysis shows seven classes of samples corresponding to the mineralogical paragenesis suggesting various sources, consisting of high-grade metamorphic, granitoids, pegmatites, basic and ultrabasic rocks, and BIFs that provided minerals to the placers. Gold mainly comes from hydrothermal quartz veins and probably from the peptization of gold from the weathering of sulfides occurring in the BIF. In the elogo region, gold exploration for primary deposits should look for and follow the hydrothermal system developed in this region. Chemical analysis for the gold grains and associated minerals is necessary to better guide the proposed

关键词： Auriferous Placers Associated Minerals Correspondence Factor Analysis Principal Component Analysis elogo Gold exploration

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Molecular Dynamics, Physical Properties, Diffusion Coefficients and Activation energy of the Lithium Oxide (Li-O) and Sodium Oxide (Na-O) electrolyte (Cathode)

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Advances in Materials Physics and Chemistry 2024年第9期14卷 213-234页

作者： Alain Second Dzabana Honguelet Abel Dominique eboungabeka timothée Nsongo Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Research Group on Physical Chemical and Mineralogical Properties of Materials Brazzaville Congo Alpha Sciences and Beta Technologies Association Brazzaville Congo Geological and Mining Research Center Brazzaville Congo

This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied a gap-free model using molecular dynamics. Physical quantities such as volume and pressure of the Na-O and Li-O systems exhibit similar behaviors around the thermodynamic ensembles NPT and NVe. However, for the Na2O system, at a minimum temperature value, we observe a range of total energy values;in contrast, for the Li2O system, a minimum energy corresponds to a range of temperatures. Finally, for physicochemical properties, we studied the diffusion coefficient and activation energy of lithium and potassium oxides around their melting temperatures. The order of magnitude of the diffusion coefficients is given by the relation Dli-O >DNa-O for the multiplicity 8*8*8, while for the activation energy, the order is well reversed eaNa-O > eaLi-O.

关键词： Molecular Dynamics Diffusion Coefficients Activation energy Lithium Oxide Sodium Oxide Lennard Jones Potential Data File Atomic and Charge Models Cathode LAMMPS

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Molecular Dynamics, Diffusion Coefficients and Activation energy of the electrolyte (Anode) in Lithium (Li and Li⁺), Sodium (Na and Na⁺) and Potassium (K and K⁺)

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Modeling and Numerical Simulation of Material Science 2024年第1期14卷 39-57页

作者： Alain Second Dzabana Honguelet timothée Nsongo Bitho Rodongo earvin Loumbandzila Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Research Group on The Physical and Chemical Properties of Materials Brazzaville Congo Association Alpha Sciences Beta Technologies Brazzaville Congo Centre for Geological and Mining Research Brazzaville Congo

This work is a simulation modelling with the LAMMPS calculation code of an electrode based on alkali metals (lithium, sodium and potassium) using the MeAM potential. For different multiplicities, two models were studied;with and without gap. In this work, we present the structural, physical and chemical properties of the lithium, sodium and potassium electrodes. For the structural properties, the cohesive energy and the mesh parameters were calculated, revealing that, whatever the chemical element selected, the compact hexagonal hcp structure is the most stable, followed by the face-centred cubic CFC structure, and finally the BCC structure. The most stable structure is lithium, with a cohesion energy of -6570 eV, and the lowest bcc-hcp transition energy of -0.553 eV/atom, followed by sodium. For physical properties, kinetic and potential energies were calculated for each of the sectioned chemical elements, with lithium achieving the highest value. Finally, for the chemical properties, we studied the diffusion coefficient and the activation energy. Only potassium followed an opposite order to the other two, with the quantities with lacunae being greater than those without lacunae, whatever the multiplicity. The order of magnitude of the diffusion coefficients is given by the relationship DLi > DNa > Dk for the multiplicity 6*6*6, while for the activation energy the order is reversed.

关键词： Molecular Dynamics Diffusion Coefficients Activation energy Lithium Alkali Metals MeAM Potential

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Study of the Physical and Mechanical Properties of Titanium in Volume by the MeAM Method

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Modeling and Numerical Simulation of Material Science 2024年第1期14卷 58-68页

作者： Yahnn J. Mighensle Mimboui Alain S. Dzabana Honguelet timothée Nsongo Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Research Group on Physical and Chemical Properties of Materials Brazzaville Congo Association Alpha Sciences Beta Technologies Brazzaville Congo Geological and Mining Research Centre Brazzaville Congo

In this work we present the results of our study on the physical and mechanical properties of titanium in volume. The work consisted in determining its physical and mechanical properties under different crystallographic structures (HCP, FCC, BCC and SC) using the Modified embedded Atom Method (MeAM) and the MeAM potential of titanium. We used the LAMMPS calculation code, based on classical molecular dynamics, to determine the most stable structure of titanium, which is the hexagonal compact structure (HCP) with crystal parameters a = 2.952 Å and c = 4.821 Å and a cohesion energy of -4.87 eV. This structure is seconded by the cubic centred structure (BCC) with a lattice parameter a = 3.274 Å and a cohesive energy of -4.84 eV. It was shown that titanium can crystallise into a third structure which is the face-centred cubic (FCC) structure with a lattice parameter a = 4.143 Å and a cohesive energy of -4.82 eV. The results obtained in this study were compared with the theoretical results and showed considerable agreement.

关键词： MeAM Potential LAMMPS Code Molecular Dynamics elastic Constants Modules Ovito

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跨越文化感悟成长--我的“一带一路”之旅

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中国有色金属 2024年第3期 70-71页

作者： timothée Nyembo Kazinguvu 不详

2023年是习近平主席提出共建“一带一路”倡议十周年,在倡议引领下,中非共同走过了充满希望的道路,一起开创了中非命运共同体的新篇章。作为中国有色集团走进刚果(金)的“先遣队”“桥头堡”,中色矿业香港控股有限公司在这一伟大征程中... 详细信息

2023年是习近平主席提出共建“一带一路”倡议十周年,在倡议引领下,中非共同走过了充满希望的道路,一起开创了中非命运共同体的新篇章。作为中国有色集团走进刚果(金)的“先遣队”“桥头堡”,中色矿业香港控股有限公司在这一伟大征程中始终坚定支持共建“一带一路”,与刚果民主共和国互学互鉴、携手i同行,守望相助、合作共赢。在友好合作与文化交流的碰撞中,香港控股公司的外事官过程中的见证者和参与者,成长为一个跨文化交流的倡导者。他的经历代表着中非友好合作的新篇章,为中非关系的发展添上了一抹鲜活的色彩。通过他的视角,我们可以更深入地了解在“一带一路”倡议下,中非友好的真正内涵以及中非命运共同体的建设之路。

关键词：中国有色集团命运共同体刚果民主共和国中非关系一带一路刚果(金) 控股公司文化交流

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Contribution of CT in the exploration of Non-Traumatic Pathologies of the Lumbar Spine in Adults in Bangui

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Open Journal of Radiology 2024年第3期14卷 125-134页

作者： Bangue Songrou Francky Kouandongui timothée Mobima Yannick Héritier Sombot Borel Tambala Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan Richard Bazogo National Center of Medical Imaging of Bangui Bangui Central Africa Republic Maman elisabeth DOMITIeN Hospital Bangui Central Africa Republic Community Hospital of Bangui Bangui Central Africa Republic

Background: In Central African Republic, a study carried out in 2019 highlighted the limits of conventional radiography in the diagnosis of non-traumatic lower back pain in adults. Objective: The objective of this study is to show the value of CT scanning in the exploration of non-traumatic pathologies of the lumbar spine in adults. Patients and Method: Retrospective and descriptive cross-sectional study covering the files of patients aged at least 18 years old, sent for lumbar scanning from March 1 to December 31, 2021 at the medical imaging center. Results: In total, 593 scan examinations were performed including 159 (26.8%) examinations of the lumbar spine. The average age of the patients was 49.84 years. The majority were male (66%). 127 (79.8%) were referred mainly to the neurology and rheumatology departments. Common low back pain (n = 97, 61%) was the main reason for requesting a CT scan. The lumbar scan was performed without contrast product in 88.7% of cases. In total, 148 (93.1%) examinations were pathological and dominated by overall disc overhang (62.2%) and somatic and interapophyseal osteoarthritis (16.9%). The other lesions were spondylodiscitis (7.4%), tumor-like lesions (3.4%) and narrow lumbar canal (1.4%).

关键词： CT Scanning Lumbar Bangui Adults

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Contribution of CT Scanning in the Investigation of Cranioencephalic Lesions in Bangui

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Open Journal of Radiology 2024年第3期14卷 156-165页

作者： Bangue Songrou Francky Kouandongui timothée Mobima Borel Tambala Yannick Héritier Sombot-Soule Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan Richard Bazogo National Center of Medical Imaging of Bangui Bangui Central African Republic Maman elisabeth DOMITIeN Hospital Bangui Central African Republic Community Hospital of Bangui Bangui Central African Republic

Introduction: Cranioencephalic exploration has always played a major role in CT scans. In the Central Africa Republic (CAR), the lack of cross-sectional imaging before the year 2020 meant that no study had focused on cranioencephalic lesions. The aim of this study was to contribute to improving the management of cranioencephalic pathologies in CAR. Patients and Method: The study took place at the Bangui National Medical Imaging Centre (CNIMB). It was a retrospective study over a two-year period (March 1, 2021 to February 30, 2023). All patients referred for cranioencephalic CT scans were included, regardless of age or sex. Results: 1745 CT scans were performed, 575 of which were cranioencephalic CT scans. The majority of patients were male (53%). Most lived in the capital Bangui (90.9%). Patients aged 61 and over were the most representative. The distribution of patients by requesting department showed that the reception and emergency department was one of the least requesting departments. The main abnormalities observed were strokes, 82.1% of which were ischaemic strokes and 17.9% haemorrhagic strokes. Strokes were followed by degenerative lesions. Post-traumatic injuries included haemorrhagic contusions (38.3%), subdural haematomas in 20.5% of cases, and extradural haematomas (9.3%). Craniofacial lesions (fractures) were observed in 45.8% of cases. Conclusion: Cranioencephalic scans accounted for 1/3 of CT examinations performed during the study period. It revealed pathologies that could not be detected by conventional means. All in all, CT scans contributed to the diagnosis of cerebral pathologies.

关键词： Cranioencephalic Scan National Medical Imaging Centre Bangui

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Simplified seismic scenario analysis of existing masonry buildings accounting for local site effects

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Frontiers of Structural and Civil engineering 2024年第2期18卷 309-318页

作者： Ayşe e.ÖZSOYÖZBAY Işıl SANRI KARAPINAR Zehra N.KUTLU İsmail e.KILIÇ Department of Civil engineering Maltepe UniversityIstanbul 34857Turkey School of engineering and Construction Oryx Universal CollegeDoha 12253Qatar

This study discusses the effects of local sites and hazard amplification on the seismic vulnerability assessment of existing masonry *** this context,a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Galata,located inİstanbul,to determine the seismic risk priority of the built *** scenarios were generated for all soil classes,different moment magnitudes,and source-to-site distances to obtain more accurate results for the seismic vulnerability assessment of the studied building ***,damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerability owing to amplification *** this study,by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment,the importance of site effects on the vulnerability and risk assessment of built heritage was *** proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerability assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results.

关键词： masonry buildings seismic vulnerability assessment cultural heritage local site effect

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CLASSIFICATIONS OF DUPIN HYPeRSURFACeS IN LIe SPHeRe GeOMeTRY

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Acta Mathematica Scientia 2024年第1期44卷 1-36页

作者： Thomas e.CeCIL Department of Mathematics and Computer Science College of the Holy CrossWorcesterMA01610USA

This is a survey of local and global classification results concerning Dupin hypersurfaces in S^(n)(or R^(n))that have been obtained in the context of Lie sphere *** emphasis is on results that relate Dupin hypersurfaces to isoparametric hypersurfaces in *** with these classification results,many important concepts from Lie sphere geometry,such as curvature spheres,Lie curvatures,and Legendre lifts of submanifolds of S^(n)(or R^(n)),are described in *** paper also contains several important constructions of Dupin hypersurfaces with certain special properties.

关键词： Dupin hypersurfaces isoparametric hypersurfaces Lie sphere geometry Lie sphere transformations Lie curvatures

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