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Depositional condition of Paleoproterozoic Francevillian carbonate rocks revisited from rare earth element contents

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Geoscience Frontiers 2024年第3期15卷 31-49页

作者： Satoshi Yoshida Karen Bakakas Mayika Yuki ishihara Mathieu Moussavou Hisashi Asanuma Tomohiko Sato Takafumi hirata Cédric Ligna Yusuke Sawaki Amboise Edou-Minko Department of Earth Science and Astronomy The University of Tokyo3-8-1 Komaba Meguro-kuTokyo 153-8902Japan Center for Northeast Asian Studies Tohoku University41 KawauchiAoba-kuSendai 980-8576Japan Department of Geology Universitédes Sciences et Techniques de MasukuBP:90190025 FrancevilleGabon Department of Earth and Planetary Science The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Geochemical Research Center The University of Tokyo7-3-1HongoBunkyo-kuTokyo 113-0033Japan Graduate School of Human and Environmental Studies Kyoto UniversityYoshida-nihonmatsuSakyo-kuKyoto 606-8501Japan Center for Fundamental Education Okayama University of Science1-1Ridai-choKita-kuOkayama CityOkayama 700-0005Japan

The Paleoproterozoic Francevillian Group in the eastern Gabonese Republic has been recently attracting increasing attention because it includes distinctive macroscopic structures interpreted as eukaryotic ***,its depositional setting and associated redox conditions need to be clearly *** clarify these,petrological studies and rare earth element(REE)abundances of carbonate rocks of the Francevillian Group in the Lastoursville basin were determined with iCP-MS coupled with a laser ablation sampling *** microscopic observations indicate that dolostones in this basin underwent the complicated diagenetic history,including sparitization,decomposition of organic matter,reduction of ferromanganese oxides,silicification,and later *** dolostones of lower Francevillian B(FB)Formation show heterogeneous textures formed by alterations during *** the alterations,changes of REE abundances and degrees of positive Y anomalies appear to have *** indicates that REE signatures in carbonate rocks can vary during *** high Mn contents in the dolostones of upper FB Formation were derived from the reduction of ferromanganese oxides in *** signatures of REE abundance in dolostones can be explained by the mixing of seawater and ferromanganese oxide *** that sense,the dolostones inherited the trace element characteristics of precursor ferromanganese oxides even after the diagenesis.Y/Ho values of the most primary parts of each sample exceed 33,the newly determined threshold value for marine carbonate rocks based on our *** magnitude of the La anomaly values also falls within the range of that of Holocene reefal *** indicate that a precursor of the dolostone of the Francevillian Group was deposited in a marine *** addition,presence of Ce anomalies in the upper FB Formation suggests that the Paleoproterozoic ocean was oxidized to such an ex

关键词： Carbonate diagenesis Francevillian Group LA-iCP-MS Seawater composition Y/Ho fractionation

The current status and future development of high-temperature conventional superconductivity

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National Science Review 2024年第7期11卷 18-20页

作者： Mikhail i.Eremets High Pressure Chemistry and Physics Group Max-Planck-Institut für Chemie

This survey highlights key advancements in high-temperature superconductivity in hydrogen-rich materials, emphasizing the robust evidence and reproducibility of superconductivity under challenging experimental conditions of megabar pressures. in the near future, achieving room-temperature superconductivity is highly probable, and the field is expected to transition towards near-ambient-pressure superconductivity.

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Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1582-1599页

作者： Goodluck i.Ofoegbu GNO Modeling Research LLC. San AntonioTX78253USA

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture *** simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid(*** re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain *** simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permeating fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density *** combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing *** are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured *** are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical *** of a single-well model are used to determine the pattern and spacing for a multiple-well *** results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than *** preexisting fractures are steeply dipping or vertical,and considering the same in situ

关键词： Discrete fracture Fracture-based continuum modeling Fracture caging High-density fracturing Hydraulic fracturing Preexisting fracture

Taxonomy,distribution,and contemporary exposure of terrestrial mammals to floods and human pressure across different areas for biodiversity conservation in China

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integrative Zoology 2024年第3期19卷 458-467页

作者： Roman SHARNUUD Eric i.AMECA MOE Key Laboratory for Biodiversity Science&Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijingChina Climate Change Specialist Group Species Survival CommissionInternational Union for Conservation of NatureGlandSwitzerland

A significant research focus is placed on identifying animal species and areas at future risk to human-induced alterations of the environment and long-term changes in climatic ***,the extent to which exposure to extreme climatic events and intense human pressure can increase the risk of harmful impacts on species remains poorly *** on terrestrial mammals in China,one of the world’s megadiverse countries,we investigated patterns of contemporary exposure to floods and human pressures and determined their taxonomic representation and distribution across three major area-based conservation schemes,namely,national nature reserves(NNRs),priority areas for biodiversity conservation(PABCs),and key biodiversity areas(KBAs).Among the 440 species assessed with moderate or high exposure to floods,327(∼75%)also qualified as moderate or high in exposure to intense human *** species mainly belong to the orders Chiroptera,Eulipotyphla,and ***,there were 305,311,and 311 species with moderate or high exposure to flood and intense human pressure represented across NNRs,PABCs,and KBAs,*** findings support the prioritization of KBAs for expansion of site-based protection efforts such as NNRs in China,considering threats to species from exposure to adverse effects from both extreme climate and human pressure.

关键词： conservation floods human pressure mammals taxonomy

Detection of 4p16.3 deletion and 11p15.5p15.4 gain in a boy by comparative genomic hybridization array:A case report

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World Journal of Clinical Cases 2024年第8期12卷 1517-1522页

作者： işın Kaya Medical Genetics Bakırçay UniversityÇiğli Education ve Training Hospitalİzmir 35620Turkey

BACKGROUND Nonallelic homologous recombination(NAHR)of segmental duplications or low copy repeats(LCRs)result in DNA gain/loss and play an important role in the origin of genomic *** SUMMARY A 3-year-old boy was referred for genetic *** genomic hybrid-ization array analysis revealed a loss of 3776 kb in the 4p16.3 chromosomal region and a gain of 3201 kb in the 11p15.5p15.4 chromosomal *** Genomic imbalances caused by NAHR in LCRs result in deletion and duplication syndromes.

关键词： Wolf-Hirschhorn syndrome Silver-Russell syndrome Recurrent rearrangements Case report

Methodology for the assessment of the friction torque of ball slewing bearings considering preload scatter

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Friction 2024年第8期12卷 1838-1857页

作者： iñigo ESCANCiANO iker HERAS Florian SCHLEiCH Josu AGUiRREBEiTiA Department of Mechanical Engineering University of the Basque CountryBilbao 48080Spain Fraunhofer-institute for Wind Energy Systems iWES Hamburg 27572Germany

This manuscript presents an innovative methodology for the assessment of the friction torque of ball slewing *** methodology aims to overcome the limitations of state-of-the-art approaches,especially when the friction torque is conditioned by the preload of the *** this end,the authors propose to simulate the preload scatter when solving the load distribution problem,prior to the friction torque *** preload scatter allows to simulate a progressive transition of the balls from a four-point contact state to a two-point contact *** implementing this capability into an analytical model,the authors achieve a successful correlation with experimental ***,depending on the stiffness of the structures to which the bearing is assembled,it is demonstrated that the rigid ring assumption can lead to inaccurate friction torque results when a tilting moment is *** methodology described in this research work is meant to have a practical ***,the manuscript provides guidelines about how to use and tune the analytical model to get a reliable friction torque prediction tool.

关键词： slewing bearing ball bearing friction torque preload scatter

Enhancement of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： i.Sardar M.D.Hossain M.S.Sikder M.N.i.Khan M.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh Material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTiR),field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSM),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTiR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEM images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity

High-temperature tribological performance of functionally graded Stellite 6/WC metal matrix composite coatings manufactured by laser-directed energy deposition

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Friction 2024年第3期12卷 522-538页

作者： Marta OSTOLAZA Alaitz ZABALA Jon inaki ARRiZUBiETA iñigo LLAVORi Nagore OTEGi Aitzol LAMiKiZ Department of Mechanical Engineering University of the Basque Country UPV/EHUPlaza Torres Quevedo 1Bilbo 48013Spain Faculty of Engineering Mechanics and Industrial ProductionMondragon UnibertsitateaLoramendi 4Mondragon 20500Spain

Wear-driven tool failure is one of the main hurdles in the *** issue can be addressed through surface coating with ceramic-reinforced metal matrix ***,the maximum ceramic content is limited by *** this work,the tribological behaviour of the functionally graded WC-ceramic-particlereinforced Stellite 6 coatings is *** that end,the wear resistance at room temperature and 400°C is ***,the tribological analysis is supported by crack sensitivity and hardness evaluation,which is of utmost importance in the processing of composite materials with *** indicate that functionally graded materials can be employed to increase the maximum admissible WC content,hence improving the tribological behaviour,most notably at high ***,a shift from abrasive to oxidative wear is observed in high-temperature wear testing.

关键词： friction coating metal matrix composite functionally graded materials high temperature laserdirected energy deposition

Synergies from off-gas analysis and mass balances for wastewater treatment--Some personal reflections on our experiences

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Environmental Science and Ecotechnology 2024年第5期21卷 413-417页

作者： Eveline i.P.Volcke BioCo Research Group Department of Green Chemistry and TechnologyGhent UniversityCoupure Links 6539000GentBelgium

Looking back at over a decade of research by herself and her group,the author advocates the added value of gas phase measurements and the application of mass balances,as well as the synergetic benefits obtained when combining *** increased application of off-gas measurements for greenhouse gas emission monitoring offers a great opportunity to look at other components in the gas phase,particularly *** balances should not be strictly reserved for modellers but also prove useful while conducting lab experiments and studying full-scale measurement *** off-gas measurements with mass balances may serve not only to quantify greenhouse gas emission factors and aeration efficiency but also to follow dynamic concentration profiles of dissolved components without dedicated sensors and/or to calculate other unmeasured ***-balance-based data reconciliation allows for obtaining reliable and accurate data,and even more when combined with off-gas analysis.

关键词： Wastewater treatment Greenhouse gas emissions Mass balances Off-gas analysis Monitoring Data reconciliation