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hydrogeology of Eastern Niger Delta: A Review

Journal of Water Resource and Protection 2020年第9期12卷 741-777页

作者： T. K. s. Abam h. O. Nwankwoala Institute of Geosciences and space Technology Rivers State University Port Harcourt Nigeria Department of Geology Faculty of Science University of Port Harcourt Port Harcourt Nigeria

This paper characterizes the aquifer system of the Niger Delta for sustainable development of the groundwater resource. The heavy-dependence on groundwater in the region and the fears of its unsustainability triggered by the weak regulations, pollution, increasing user population and industrialization coupled with the present limited knowledge of the true geological condition prevailing within the groundwater domain of the Niger Delta are the considerations that compelled this review study. The hydraulic properties of the region’s aquifers are discussed. The Niger Delta is characterized by a complex multilayered aquifer system hosted in the Benin Formation with the main body of fresh water, with increasing occurrence of intercalating clay units towards the coast. Lithological analysis indicates the prevalence of unconsolidated sand and sandy gravels in the aquiferous horizons, presenting them as pervious and prolific aquifers. Reported hydrochemical data gathered from wells drilled suggest that the quality of groundwater in the Niger Delta is considered generally very good and compares favorably with WhO standards for drinking water. however, relatively high iron/manganese and chloride values are localized in time and space. In the coastal areas however, seawater intrusion has been identified as one of the major influences on hydrochemistry of groundwater in the shallow unconfined aquifers. Regional groundwater flow direction is from north to south. Changes in groundwater flow directions which occur at some places generally serve localized discharge areas. The resultant flow path eventually joins and feeds the major regional north-south flow direction. The increasing pressure on groundwater, the need for urgent attention and the absence of strong institutions and regulations have made the management of groundwater resources in the region a difficult task. Therefore, future ground water resources development in the Niger Delta requires adequate observational data, in

关键词： hydrogeology Groundwater Quality saline Water Intrusion Aquifer Water Table Niger Delta

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Indications and Results of surgical Treatment of Proximal Femoral Fractures in Adults at Ouagadougou

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Open Journal of Orthopedics 2018年第5期8卷 200-212页

作者： s. C. Da h. Kafando A. s. Korsaga s. Tinto A. Wangrawa M. Tall Centre hospitalier Universitaire Yalgado Oué draogo (ChU YO) Ouagadougou Burkina Faso

Background: Functional treatment of proximal femur fractures (PFF) is being discontinued with advances in surgery and anesthesia. suspension traction is used as a waiting treatment before surgery when technical, material and financial conditions are not met. The surgical treatment of these fractures must ensure a stable reduction and fixation, to allow early support to the patient who will quickly regain his previous autonomy. Objective: To specify the indications for surgical treatment of proximal fractures in adult in order to evaluate the results in the context of Burkina Faso. Patients and Methods: We conducted a retrospective study including adult patients hospitalized and followed up for proximal femoral fracture (PFF) in the orthopedic-traumatology department of the Yalgado Ouedraogo University hospital Center at Ouagadougou. Among 310 patients presenting with PFF in 5.5 years, (56 cases a year (10.4%)), we focused on those whose PFFs were treated by surgical methods and followed up. Patients treated with orthopedic (40.1%) or functional (6.8%) methods, patients with incomplete records and those having signed a discharge against medical advice were excluded. A total of 94 patients, with 95 PFFs treated by surgical methods, constituted our study population. Road traffic accidents (51.1%) and domestic accidents (48.9%) were the predominant etiologies. The functional criteria of Postel Merle d’Aubigné (PMA) were used for the evaluation of the results (Table 1). Results: A total of 65 men and 29 women (sex ratio 2.2), aged of average 56 years, were recorded. Trochanteric mass fractures were predominant with 63 cases (66.3%), including one case of bilateral fracture and one case of an open fracture;we also reported 32 femoral neck fractures (33.7%). Osteosynthesis was performed in 66 patients (70.2%) and hip arthroplasty in the remaining 28 patients (29.8%). Osteosynthesis with Dhs plate screws was performed in 49 cases (73.1%) and Moore type cephalic arthroplasty

关键词： Fractures Proximal Extremity Femur Treatment

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LIThIUM ORDERING IN ChEMICALLY DELIThIATED Li_xCoO_2

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Acta Metallurgica sinica(English Letters) 2006年第3期19卷 197-202页

作者： X. Liu W.h. Tian h.X. Yang Y. G. shi J. Q. Li Department of Materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China Beijing National Laboratory for Gondensed Matter Physics Institute of Physics The Chinese Academy of Sciences Beijing 100080 Ghina

Chemical delithiated LixCoO2 （x=1, 0.7, 0.66 and 0.57） has been synthesized by using a strong oxidant, Nas2O8 .The structure investigations indicate that all the samples remain with hexagonal cells, which have expansion of c axis during Li extraction. Transmission electron microscopy （TEM） observations revealed the presence of superstructures arising from intercalated U-ordering corresponding to first-principle calculations. The measurements of the physical properties are also influenced by Li concentration.

关键词： LixCoO2 delithiated Li-ordering

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Performance of Echo Canceller during start-up for high-speed Data Transmission

Performance of Echo Canceller during Start-up for High-Speed...

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计算机，通信，控制与电力工程国际会议

作者： s. s. F. hau Y. h. Chan K. s. Ngai P. h. s. Lam Department of Electronic Engineering Hong Kong Polytechnic Hong Kong

Echo Cancellers that use the spectral estimation approach for the fastest possible starting-up time need to know the approximate delay and duration of the echo,and require a cyclic input of a pseudo-noise(PN) *** paper describes the effects of an inaccurate estimate of the echo duration by the initial sounding of the echo *** also compares the performance of the well-known Barker sequences,the Relaxed-Barker sequences,and the arbitrarily constructed PN sequences when used for the starting up *** offers an explanation and gives the necessary characteristics of the PN sequences that ensure the successful operation of the echo canceller. Finally the paper gives a guideline for the choice of a suitable PN sequence for the estimation of an unknown echo path of any but roughly-known duration.

关键词： Performance of Echo Canceller during start-up for high-speed Data Transmission

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Long-term flexible penetrating neural interfaces:materials, structures, and implantation

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science China(Information sciences) 2021年第12期64卷 5-22页

作者： Chi GU Jianjuan JIANG Tiger h.TAO Xiaoling WEI Liuyang sUN state Key Laboratory of Transducer Technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences University of Chinese Academy of sciences school of Physical science and Technology Shanghai Tech University Center of Materials science and Optoelectronics Engineering University of Chinese Academy of Science 52020 X-Lab Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences shanghai Research Center for Brain science and Brain-Inspired Intelligence Center for Excellence in Brain science and Intelligence Technology Chinese Academy of Sciences

Penetrating neural interface, which collects the neural electrophysiological signal and serves as a key component in brain-computer interface, has drawn great attention recently. The instability of chronic recording is the main challenge for the conventional neural interface. Novel neural probes with improved long-term performance have been developed based on advanced materials and engineered structures. here, we review these emergent innovations contributing to chronic stable recording from the perspectives of materials,structures, and implantation methods. These advances make possible further developments in neuroscience research related to neural decoding, neural circuit mechanism analysis, and neurological disease treatment.

关键词： neural interface long-term flexible minimally invasive biocompatibility

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MICROsTRUCTURAL EVOLUTION OF hIGhLY UNDERCOOLED EUTECTIC Ni78.6 si21.4 ALLOY

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Acta Metallurgica sinica(English Letters) 2006年第1期19卷 43-50页

作者： Y.P. Lu G. C. Yang C.L. Yang h.P. Wang Y.h. Zhou state Key Laboratory of solidification Processing Northwestern Polytechnical UniversityXi＇an 710072 China Department of Applied Physics Northwestern Polytechnical University Xi＇an 710072China

A large undercooling level up to 550K （0.386Te） was achieved in eutectic Ni78.6si21.4melt by the combination of molten-glass and cyclic superheating. A microcrystaUine structure is obtained at large undercooling. surprisingly, the morphology of ct（Ni） phase transits from the non-faceted phaseto faceted phase at large undercooling of 390K. Based on the classical nucleation theory and transient nucleation theory, the process of microstructure evolution and competitive nucleation was analyzed, and the refinement of crystal structure is determined by the high nucleation rate under large undercooling.

关键词： high undercooling molten-glass eutectic rapid solidification

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single-molecule DNA sequencing using two-dimensionalTi2C(Oh)2 MXene nanopores: A first-principles investigation

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Nano Research 2022年第11期15卷 9843-9849页

作者： Jariyanee Prasongkit sirichok Jungthawan Rodrigo G.Amorim Ralph h.scheicher Division of Physics Faculty of ScienceNakhon Phanom UniversityNakhon Phanom 48000Thailand school of Physics Institute of ScienceSuranaree University of Technology111 University AveNakhon Ratchasima 30000Thailand Center of Excellence in Advanced Functional Materials Suranaree University of TechnologyNakhon Ratchasima 30000Thailand Thailand Center of Excellence in Physics Ministry of Higher EducationScienceResearch and Innovation328 Si Ayutthaya RoadBangkok 10400Thailand Departamento de Física ICExUniversidade Federal Fluminense-UFFVolta Redonda/RJ 27213-145Brazil Division of Materials Theory Department of Physics and AstronomyUppsala UniversityUppsala SE-75120Sweden

Nanopore-based devices have provided exciting opportunities to develop affordable label-free DNA sequencing *** a decade ago,graphene has been proposed as a two-dimensional(2D)nanopore membrane in order to achieve single-base ***,it was experimentally revealed that clogging of the graphene nanopore can occur due to the hydrophobic nature of graphene,thus hindering the translocation of *** overcome this problem,the exploration of alternative 2D materials has gained considerable interest over the last *** we show that a Ti_(2)C-based MXene nanopore functionalized by hydroxyl groups(–Oh)exhibits transverse conductance properties that allow for the distinction between all four naturally occurring DNA *** have used a combination of density functional theory and non-equilibrium Green’s function method to sample over multiple orientations of the nucleotides in the nanopore,as generated from molecular dynamics *** conductance variation resulting from sweeping an applied gate voltage demonstrates that the Ti_(2)C-based MXene nanopore possesses high potential to rapidly and reliably sequence *** findings open the door to further theoretical and experimental explorations of MXene nanopores as a promising 2D material for nanopore-based DNA sensing.

关键词： nanopore DNA sequencing MXenes first-principles quantum transport

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EFFECT OF Zr ADDITION TO Ti-KILLED sTEEL ON INCLUsION FORMATION AND MICROsTRUCTURAL EVOLUTION IN WELDING INDUCED COARsE-GRAINED hEAT AFFECTED ZONE

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Acta Metallurgica sinica(English Letters) 2008年第3期21卷 220-226页

作者： F. Chai C.F. Yang h. su Y.Q. Zhang Z. Xu Y.h. Yang Institute for structural Materials Central Iron and Steel Research Institute Beijing 100081 China school of Materials science and Engineering Shanghai Jiaotong University Shanghai 200030 China school of Materials science and Engineering Kunming University of Science and Technology Kunming650093 China

Effects of Zirconium on the chemical component and size distribution of Ti-bearing inclusions, favored the grain refinement of the welding reduced, coarse-grained heat affected zone （CGhAZ） with enhanced impact toughness in Ti-killed steels, which were examined based on experimental observations and thermodynamic calculations. It indicated that the chemical constituents of inclusions gradually varied from the TiO oxide to the Ti-O＋Zr-O compound oxide and a single phase of the ZrO2 oxide, as the Zr content increased from zero to 0.0100%. A trace of Zr （0.0030%-0.0080%, depending on the oxygen content in liquid steel） provided a large amount of nucleating core for Ti oxide because of the larger specific density of ZrO2 oxide, and produced a small size distribution of the inclusions favorable for acicular ferrite transformation with a high nucleation rate in the CGhAZ, and a high volume fraction of acicular ferrite was obtained in the CGhAZ, with enhanced impact toughness. Otherwise, a high content of Zr （-0.0100%） produced a single phase Zr02, which was impotent to nucleate acicular ferrite, and a microstructure composed of ferrite side plate and grain boundary ferrite developed in the CGhAZ. The experimental results were confirmed by thermodynamic calculations.

关键词： Nonmetallic inclusions Zirconium Acicular ferrite Coarse-grain heat affected zone (CGhAZ)

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Effective use of FibroTest to generate decision trees in hepatitis C

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World Journal of Gastroenterology 2009年第21期15卷 2617-2622页

作者： Dana Lau-Corona Luís Alberto Pineda héctor hugo Avilés Gabriela Gutiérrez-Reyes Blanca Eugenia Farfan-Labonne Rafael Núez-Nateras Alan Bonder Rosalinda Martínez-García Clara Corona-Lau Marco Antonio Olivera-Martínez Maria Concepción Gutiérrez-Ruiz Guillermo Robles-Díaz David Kershenobich Department of Experimental Medicine School of MedicineUniversidad Nacional Autonoma de MexicoGeneral Hospital of Mexico Department of Computer sciences Institute for Applied Mathematics and SystemsUniversidad Nacional Autonoma de Mexico Department of Gastroenterology Lomas Altas Clinic

AIM： To assess the usefulness of FibroTest to forecast scores by constructing decision trees in patients with chronic hepatitis C.METhODs： We used the C4.5 classification algorithm to construct decision trees with data from 261 patients with chronic hepatitis C without a liver biopsy. The FibroTest attributes of age, gender, bilirubin, apolipoprotein, haptoglobin, α2 macroglobulin, and γ-glutamyl transpeptidase were used as predictors, and the FibroTest score as the target. For testing, a 10-fold cross validation was used.REsULTs： The overall classification error was 14.9% （accuracy 85.1%）. FibroTest＇s cases with true scores of FO and F4 were classified with very high accuracy （18/20 for FO, 9/9 for FO-1 and 92/96 for F4） and the largest confusion centered on F3. The algorithm produced a set of compound rules out of the ten classification trees and was used to classify the 261 patients. The rules for the classification of patients in FO and F4 were effective in more than 75% of the cases in which they were tested.CONCLUsION： The recognition of clinical subgroups should help to enhance our ability to assess differences in fibrosis scores in clinical studies and improve our understanding of fibrosis progression,

关键词： hepatitis C FibroTest Decision trees C4.5algorithm Non-invasive biomarkers

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Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-hz pulse DC discharge technique

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Chinese Physics B 2014年第10期23卷 349-356页

作者： U.Ikhlaq R.Ahmad M.shafiq s.saleem M.s.shah T.hussain I.A.Khan K.Abbas M.s.Abbas Department of Physics Government College University Centre for Advanced studies in Physics (CAsP) Government College University Department of Physics Quaid-i-Azam University Department of Physics GC University Faisalabad

Molybdenum is nitrided by a 100-hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry （XRD）, scanning electron microscopy （sEM）, and atomic force microscopy （AFM） are used for the structural and morphological analysis of the nitrided layers. Vickers＇ microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar （1 bar = 105 Pa）. A considerable increase in surface microhardness （approximately by a factor of 2） is observed for longer duration （10 h） and 2-mbar pressure. Longer duration （10 h） and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen.

关键词： pulsed DC glow discharge scanning electron microscopy atomic force microscopy microhard-ness

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