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Lamella Silicon Solar Cell under Both Temperature and Magnetic Field: Width Optimum Determination

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Journal of Electromagnetic Analysis and Applications 2020年第4期12卷 43-55页

作者： Dibor Faye Sega Gueye Mor Ndiaye Mamadou Lamine ba Ibrahima Diatta Youssou Traore Masse Samba diop Gora diop Amadou Diao Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal

This work deals with determining the optimum thickness of the lamella wafer of silicon solar cell. The (p) base region makes up the bulk of the thickness of the wafer. This thickness has always been a factor limiting the performance of the solar cell, as it produces the maximum amount of electrical charges, contributing to the photocurrent. Determining the thickness of the wafer cannot be only mechanical. It takes into account the internal physical mechanisms of generation-diffusion-recombination of excess minority carriers. They are also influenced by external factors such as temperature and magnetic field. Under these conditions, magneto transport equation is required to be applied on excess minority carrier in lamella base silicon solar cell. It yields maximum diffusion coefficient which result on Lorentz law and Umklapp process. Then from photocurrent, back surface recombination velocity expressions are derived, both maximum diffusion coefficient and thickness dependent. The plot of the back surface recombination calibration curves as function of lamella width, leads to its maximum values, trough intercept points. Lamella optimum width is then obtained, both temperature and magnetic field dependent and expressed in relationships to show the required base thickness in the elaboration process.

关键词： Silicon Vertical Junction back Surface Recombination Velocity Magnetic Field Temperature Lamella Width

Grain Size Influence on the Compaction Aptitude and the Bearing Strength of the Gravel Lateritic Soils

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Geomaterials 2018年第4期8卷 63-76页

作者： baye Oumar diop Ignace Gbaguidi Papa Goumbo Lo Aminata Cisse Seynabou Sène Makhaly ba cole Supérieure Polytechnique Université Cheikh Anta Diop Dakar Senegal Institut des Sciences de la Terre Faculté des Sciences et Techniques Université Cheikh Anta Diop Dakar Senegal Centre Expérimental de Recherches et d’études pour l’équipement (CEREEQ)1 Dakar Senegal AGEROUTE-Sénégal Fann Résidence Dakar Senegal UFR Sciences de l’Ingénieur Université de Thiès Thiès Senegal

This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specifications and on the laboratory tests, but also all of the material that is actually used in the construction sites. Geotechnical characterization was leaned on five differentiated granular classes of 0/20;0/25;0/31.5;0/40 and 0/63 mm diameters. The sample of 0/40 mm gets the best compaction aptitude, while that of 0/31.5 mm reaches the greatest bearing strength and a good Optimum Moisture Content. According to the requirements and its bearing strengths, the material is usable up to subbase layer and its behavior depends on the grain size.

关键词： Granular Class Bearing Strength Optimum Modified Proctor (OMP) Gravel Lateritic Soils Pavement

Giant Cerebriform Nevus Cell Nevus of the Scalp: A Case Report

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Open Journal of Modern Neurosurgery 2024年第1期14卷 8-13页

作者： Mohamed El Hassimi Cissé N’daraw Ndoye Anne Aurore Sankale Pauline Diousse Abdoulaye diop Alvine Nah Doe Sagar diop Momar Codé ba Seydou Boubakar badiane Neurosurgery Department of CHU Mère-Enfant “Le Luxembourg” Bamako Mali Neurosurgery Department of CHNU de Fann Dakar Sénégal Plastic and Cosmetic Surgery Department of CHU Le Dantec Dakar Sénégal Dermatology Department of Thiès Regional Hospital Thiès Sénégal

Giant cerebriform nevus cell nevus of the scalp is an extremely rare form of congenital melanocytic nevus. Giant cerebriform nevus of the scalp has a major psychosocial impact because of its unsightly appearance with fetid maceration. We report the case of a 35-year-old woman who had a painless, malodorous swelling of the cerebriform scalp measuring 20 × 17 cm in diameter with a wide base of insertion at the occipital level adhering to the deep planes. The excision associated with a skin plasty was carried out. Histology concluded that there was a giant cerebriform naevo-cellular nevus of the scalp.

关键词： Giant Nevus Tumor of the Scalp Resection

Indications and Results of Repair of the Rhumatismal Valve in Children in Senegal concerning 63 Cases

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World Journal of Cardiovascular Surgery 2020年第5期10卷 51-58页

作者： Momar Sokhna diop Papa Amath Diagne Ndeye Fatou Sow Papa Salmane ba Magaye Gaye Pape Ousmane ba Souleymane Diatta Moussa Seck diop Mareme Soda Mbaye Pape Adama Dieng Amadou Gabriel Ciss Assane Ndiaye Thoracic and Cardiovascular Surgery Center Cheikh Anta Diop University Dakar Sénégal

In Africa, acute rheumatic fever is endemic. Cardiac involvement is one of the most common complications in the form of valvular heart disease representing all damages to the heart valves. It is in this perspective that we realized this study whose general objective was to evaluate the results of mitral repair surgery in children in Senegal and the specific objective was to state the indications for mitral repair surgery and assess the results in terms of morbidity and mortality. This is a retrospective and analytical monocentric study, in the thoracic and cardiovascular surgery department of FANN National University Hospital Center in Dakar. It took place over a period of 30 months. All the patients who underwent mitral surgery, aged less than 18 years were included. The total number of patients was 63, including 39 girls and 24 boys, a sex ratio of 0.62. The average age at the time of the surgery was 12 years old [5 - 17]. The functional symptomatology was dominated by the dyspnea found in all the patients. Cardiac ultrasound was diagnosed with mitral regurgitation in all patients. For all surgical procedures, the approach was a vertical midline sternotomy. The mitral valve was approached by left atriotomy in 40 patients (63.5%) and by transseptal way in 23 patients. All patients had undergone mitral valve repair associated or not with either aortic valve repair in 9 patients (14.2%), aortic valve replacement in 3 patients (4.8%), or one tricuspid valve repair in 31 patients (49%). The average duration of intubation was 6 hours [2 - 52]. The average length of stay in intensive care was 2 days. Postoperative complications have been observed. Surgery was performed in 10 patients with 3 mitral valve replacements, 2 aortic valve replacements, a double mitral and an aortic valve replacement associated with a tricuspid repair and in 4 cases a perfection of their mitral repair. Early and late surgical mortality was zero. The average follow-up time for our patients was 9

关键词： Mitral Valve Repair Acute Rheumatic Fever Senegal

Thoracolumbar Spine Fracture-Dislocation without Neurological Deficit: A Case Report and Review of the Literature

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Open Journal of Orthopedics 2021年第5期11卷 153-163页

作者： Roger Mulumba Ilunga Abdoulaye diop Mohameth Faye Vital Nacoulma Nicaise Akodjetin Mahougnon Sodjinou Momar Codé ba Department of Neurosurgery Regional Hospital Center of Thiès Thiès Senegal Department of Neurosurgery Regional Hospital of Ziguinchor Ziguinchor Senegal Department of Neurosurgery National Teaching Hospital of Fann Dakar Senegal

background: Thoracolumbar spine fracture-dislocations are very unstable and usually secondary to high energy trauma. Due to disruption of the entire vertebrae columns, the absence of neurological deficit is exceptiona... 详细信息

Background: Thoracolumbar spine fracture-dislocations are very unstable and usually secondary to high energy trauma. Due to disruption of the entire vertebrae columns, the absence of neurological deficit is exceptional. Aim: The purpose of this work is to report our experience in the management of this entity in a context of limited resources and to make a review of the literature. Case presentation: A 30-year-old man was admitted with a severe low back pain after a traffic accident. Neurological functions were intact after examination. Radiological assessments revealed a complete L3-L4 fracture-dislocation. The patient underwent an open posterior reduction and internal long segment fixation. The post-operative was marked by a surgical site infection treated with surgical debridement and targeted antibiotic therapy. The neurological functions were preserved. Conclusion: Fracture-dislocations of the thoracolumbar spine are caused by high energy trauma and are remarkably unstable lesions. When they are associated with intact neurorological functions, reduction and stabilization of these fractures are a challenge.

关键词： Spine Fracture-Dislocation Thoracolumbar Spine Spine Surgery Trauma

base Thickness Optimization of a (n+-p-p+) Silicon Solar Cell in Static Mode under Irradiation of Charged Particles

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Journal of Electromagnetic Analysis and Applications 2019年第10期11卷 173-185页

作者： Mamadou Lamine ba Ndeye Thiam Moustapha Thiame Youssou Traore Masse Samba diop Mamour ba Cheikh Tidiane Sarr Mamadou Wade Gregoire Sissoko Laboratory of Sciences and Techniques of Water and Environment Polytechnic School of Thiès Thiès Senegal Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal.

In this work, we propose a method to determinate the optimum thickness of a monofacial silicon solar cell under irradiation. The expressions of back surface recombination velocity depending the damage coefficient (kl) and irradiation energy (øp) are established. From their plots, base optimum thickness is deduced from the intercept points of the curves. The short-circuit currents Jsc0 and Jsc1 corresponding to the recombination velocity Sb0 and Sb1 are determinated and a correlation between the irradiation energy, the damage coefficient and optimum thickness of the base is established.

关键词： Silicon Solar Cell Irradiation Recombination Velocity base Thickness

St-Segment Elevation Myocardial Infarction with Multiple Complications: A Case Report

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World Journal of Cardiovascular Diseases 2023年第3期13卷 124-129页

作者： Khadimu Rassoul diop Mame awa Sene Serigne Mor Beye Joseph Salvador Mingou Aliou Alassane Ngaïdé Youssou Diouf Papa Guirane Ndiaye Cheikh Mouhamadou bamba diop Marguerite Tening Diouf Adama Kane Maboury Diao Abdoul Kane Department of Cardiology CHU Aristide Le Dantec Dakar Senegal Department of Cardiology Dalal Jamm Hospital Dakar Senegal Department of Cardiology Saint Louis Regional Hospital Saint Louis Senegal Department of Cardiology Idrissa Pouye General Hospital Dakar Senegal

Introduction: ST-Segment Elevation Myocardial Infarction (STEMI) usually involves complete thrombotic occlusion of a coronary artery and require urgent reperfusion;it is one of the leading cause of global mortality and morbidity worldwide. A variety of mechanical, rhythmic, conductive, embolic or hemodynamic complications can occur following STEMI, especially when the treatment is delayed or inadequate. Clinical presentation: A 58-year-old patient with hypertension was admitted to our department for a circumferential STEMI complicated by an ischemic stroke;received 24 hours after the onset of pain. His blood pressure was 100/60 mmHg, heart rate was 55 beats/min. The examination revealed right central facial paralysis and a slight motor deficit of the right upper limb (muscle strength 4/5). The first electrocardiogram (ECG) showed a significant circumferential ST-segment elevation with Q waves in the same territory, as well as a Luchiani Wenckebach atrio-ven- tricular block. The first echocardiography performed showed apical akinesia along with the presence of an apical thrombus. Coronarography was not performed because it was not available and the patient was given curative low molecular weight heparin combined with dual antiplatelet therapy, an angiotensin converting enzyme inhibitor and high dose statins. Seventy-two hours later, the ECG showed a complete atrioventricular block with narrow QRS and the average ventricular rate was 51 beats/min. The patient was asymptomatic. Another echocardiography was performed to assess new complications and showed a rupture of the left ventricular wall and a moderate amount of circumferential pericardial effusion, without any sign of cavity compression. No particular therapeutic attitude was adopted apart from close monitoring with daily ECG and echocardiography. Ten days later, spontaneous regression of the AV Bloc was noted. Conclusion: ST-Segment Elevation Myocardial Infarction is a major cause of morbidity and mortality worl

关键词： Myocardial Infarction Delayed Reperfusion Complication

High-Field MRI Contribution in Tolosa-Hunt Syndrome (THS). Report of Two Cases and Review of Literature

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Open Journal of Radiology 2018年第3期8卷 141-149页

作者： Chérif Mohamadou Aidara Philomène Kouna Jennifer Nyangui Mapaga Nfally badji Hamidou Deme Abdoulaye Dione diop Abdoulaye Ndoye diop Sokhna ba El Hadj Niang Radiology Department Fann University Hospital Dakar Sénégal Neurology Department El Rapha Polyclinic Trois Quartiers BP 256 Libreville Gabon

background: Tolosa Hunt Syndrome is an inflammatory condition of unknown etiology of the cavernous sinus and superior orbital fissure. Because of the difficulty in establishing histological evidence, his diagnosis is based on a set of arguments established by the International Headache Society. MRI allows indirect visualization of the granuloma and plays a key role in diagnosis and follow-up. Aim: To illustrate High-field MRI contribution in Tolosa-Hunt Syndrome (THS). Cases Presentation: Two patients, a 25-year-old female and a 40-year-old male were recruited in this retrospective case report study at the Radiology service of Fann University Hospital (Dakar Senegal). The first patient has been suffering from a right retro-orbital pain and diplopia for 2 months and the second from a painful oculomotor nerve palsy for 3 months. Blood tests, lumbar puncture, thyroid hormone levels and an infectious screen were done. Screening for converting enzymes, and serum antibodies were also done. They underwent a high field MRI (Siemens 1.5T) with T1, T2, FLAIR, T2*, diffusion B1000, TOF polygon, CISS 3D and T1 gadolinium sequences in the 3 planes space. No significant abnormality was detected in blood tests or CSF analysis. Screening for converting enzymes and serum antibodies screen were also negative. For each patient, MRI examinations showed a non tumoral thickening of the right cavernous sinus, suggesting a granulomatous involvement. Tolosa Hunt Syndrome was evoked firstly. They were put on corticotherapy at high doses with a spectacular regression of symptoms. The Criteria of the International Headache Society of THS were met in both patients. Conclusion: High-field MRI is a significant diagnostic tool in the assessment of painful ophthalmoplegia. It allows a direct visualization of the granuloma of the cavernous sinus and assesses its course throughout the disease.

关键词： Painful Ophthalmoplegia Tolosa-Hunt Syndrome Criterias of International Headache Society High-Field MRI

Diffusion Coefficient at Resonance Frequency as Applied to n+/p/p+ Silicon Solar Cell Optimum base Thickness Determination

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Journal of Electromagnetic Analysis and Applications 2020年第10期12卷 145-158页

作者： Amadou Mar Ndiaye Sega Gueye Mame Faty Mbaye Fall Gora diop Amadou Mamour ba Mamadou Lamine ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal Ecole Polytechnique de Thiès Thiès Sénégal Département Génie Electrique Ecole Supérieure Polytechnique de Nouakchott Nouakchott Mauritanie

The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (D(ω, B), in the (p) base leads to maximum values (Dmax) at resonance frequencies (ωr). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, ωr and B, are then established, and will be data for industrial development of low-cost solar cells for specific use.

关键词： Silicon Solar Cell Resonance Frequency Magnetic Field Recombination Velocity base Thickness