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机电技术 1982年第1期 16-20页

作者： ur.普拉萨德王莉芳缅甸合作社部家庭手工业司司长助理

在缅甸,用来灌溉的提水工具从十分简单的水桶到非常复杂的水泵.由于石油短缺而且价格较高,可再生能源如风力、水力和太阳能,以及人力正逐渐成为灌溉的主要能源。

关键词：提水管井自吸泵水泵取水化工用泵水锤泵吸水管路自吸离心泵自吸式离心泵提水工具缅甸农业

Ion-acoustic waves with non-planar wavefronts

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Plasma Science and Technology 2024年第1期26卷 1-7页

作者： Shujaht BUKHARI Muhammad SHAHID Ata-ur.RAHMAN Department of Physics The University of Azad Jummu and KashmirMuzaffarabad 13100Azad Kashmir Department of Physics Women University of Azad Jammu&KashmirBagh 12500Pakistan Department of Physics Islamia College PeshawerPeshawar 25120Pakistan

The ion-acoustic(IA) mode exhibiting various orbital angular momentum(OAM) states is examined in a plasma with drifting *** constituent plasma species are modeled with a non-gyrotropic Maxwellian distribution and discussion of dispersion relation and growth rate of twisted IA waves under various conditions is *** the domain of kinetic model,the twisted IA waves are characterized by Laguerre-Gaussian(LG) solutions,where plasma distribution function and electric field are decomposed into axial and azimuthal *** plasma response function is obtained under paraxial approximations and investigated for threshold condition of instability growth rate with helical electric field *** impact of an extra electron specie on the instability is demonstrated through a comparison of twisted waves for single and double electron species.

关键词： instability twist parameter wave excitation orbital angular momentum threshold limit

Facile synthesis of samarium and cerium doped double perovskite cobaltite with enhanced dielectric response

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Jour.al of Rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas M.Kamran M.Anis-ur.Rehman Applied Thermal Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm-Ce doping on structur.,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm_(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are *** the specimens were synthesized by a facile synthesis technique named the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice parameters,lattice strain,unit cell volume,and bulk density were determined using XRD *** structur.l properties of Bi_(2)Ca_(2)CoO_(6)were examined using calculations based on the density functional *** and experimental values discrepancy is less than 1%.A scanning electron microscope was used for performing a microstructur.l *** SEM images demonstrate the homogeneous distribution of grains with a range of sizes(0.054-0.090μm).The alternating cur.ent(ac)conductivity,dielectric permittivity,and tangent loss were also studied as a function of frequency(20 Hz-3 MHz)at different temperatur.s(100-500℃).All synthesized samples were examined using non-linear Debye's function to determine their spreading factor and relaxation *** specimen with the lowest crystallite size(∼23 nm)exhibits a high dielectric permittivity(∼3.80×10^(6)).The conduction mechanism was examined in the studied samples with the use of Jonscher's power *** power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 compositions follow non-overlapping polaron *** studied specimen Bi_(2)Ca_(1.9)0Sm_(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm^(3))displays a high electrical conductivity(∼46.1 S/cm).These findings correspond to those published for ceramics made from calcium cobaltite using solid-state reactions(5.0-26.0 S/cm).

关键词： Bismuth calcium samarium cerium cobaltite (BCSCCO) Spreading factor Conduction mechanism Rare earths

The impact of being in the COVID-19 pandemic on in-hospital mortality of non-infected patients aged 80 years and older with ST-elevation myocardial ınfarction

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Jour.al of Geriatric Cardiology 2024年第7期21卷 768-774页

作者： Mustafa Ebik Muhammet Gürdoğan Uğur.zkan Department of Cardiology Edirne SultanMurat State HospitalEdirneTurkey Department of Cardiology School of MedicineTrakya UniversityEdirneTurkey

The COVID-19 outbreak in late 2019 was declared a pandemic by the World Health Organization(WHO)on March 12,2020.[1]As of the latest WHO data,COVID-19 has caused over 770 million cases and nearly 7 million deaths worldwide.[2]Hospitalizations due to COVID-19 are correlated with advanced age.[3,4]According to re-ports,individuals over the age of 65 account for 80%of COVID-19-related deaths.[3,4]This is primar-ily due to the increased bur.en of comorbidity with age.

关键词： infected patients mortality

Fabrication and application prospects of Pr-Fe-B/Alnico nanocomposite alloys

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Jour.al of Rare Earths 2024年第9期42卷 1717-1723,I0003页

作者： Hui Liang Sajjad ur.Rehman Ruibiao Zhang Yongqiang Deng Haihua Liu Munan Yang National Rare Earth Functional Materials Innovation Center College of Rare EarthsJiangxi University of Science and TechnologyGanzhou341000China Zhejiang Tiantong Electronic Information Materials Research Institute Co. Ltd.Haining314400China

The potentials of rare earth-based nanocomposite alloys have never been realized due to strict microstructur.l *** to the easy demagnetization it is challenging to increase the soft magnetic phase *** avoid the easy demagnetization,Pr-Fe-B/Alnico magnets were fabricated and reported in this *** content of the Alnico phase is increased from 0 to 25 wt%,while the content of Pr element is reduced to below the sub-stoichiometry of the 2:14:1 main *** maximum magnetic energy product,which is the figur.-of-merit for permanent magnets,is increased from 122 kJ/m^(3) for the standard alloy to 146 kJ/m^(3) for the alloy with 15 wt% Alnico which shows a significant improvement considering the fact that the Cur.e point of the magnet is also increased by~66 *** special microstructur. contains distinctly and heterogeneously distributed 2:14:1 and Alnico *** dimensions of neither the 2:14:1 nor the Alnico phases meet the dimensional requirements of the nanocomposite magnets,but still the smooth demagnetization cur.es are noted for the *** behavior of effective anisotropy,the performance of the magnets in applied magnetic field and the magnetic interactions among the various constituent grains were quantitatively studied by reversible susceptibility,irreversible susceptibility and re coil loop *** study may provide some guiding principles for the development of nanocomposite magnetic alloys with excellent magnetic properties by using much less RE elements.

关键词： Composite alloys High performance magnets Magnetic properties Alnico alloys Rare earth magnets

Changes in Calcareous Nannofossil Assemblages and Paleoenvironmental Interpretation of the Early Miocene Lice Formation, Kahramanmara? Basin, Tur.ey, East Mediterranean

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1021-1034页

作者： Caner KAYAÖZER Muazez Esra ORHAN Uğur.TEMİZ Yozgat Bozok University DivanlıRoadYozgat 66900Turkey

This study investigated the calcareous nannofossil assemblages in detail from the early Miocene aged Lice Formation outcropping in the Kahramanmara? basin. The biostratigraphy of calcareous nannofossils was outlined and paleoenvironmental featur.s determined. In 81 samples taken from three measur.d sections in the region, 17 calcareous nannofossil genus and 48 nannofossil species were identified. These calcareous nannofossil genus and species identified the Lice Formation as being in the CNM4 nannofossil biozone. The abundance and diversity of early Miocene calcareous nannofossil species varied in the measur.d sections, with the samples generally moderate-poor, apart from a few samples. The relative abundance of individuals of Cyclicargolithus floridanus, Coccolithus pelagicus, Reticulofenestra hagii and Sphenolithus moriformis species, with paleoecological importance identified in the study region, indicate that in early Miocene times, the basin in which the Lice Formation deposited was meso-eutrophic with excess nutrient input, temperate and generally stable shallow marine conditions.

关键词： paleoecology nannofossil Bur.igalian East Mediterranean

Polyhydroxyur.thanes from Biobased Monomers and CO_(2):A Bridge between Sustainable Chemistry and CO_(2) Utilization

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Chinese Jour.al of Chemistry 2024年第6期42卷 652-685页

作者： Tharinee Theerathanagorn Tanika Kessaratikoon Hafeez ur.Rehman Valerio D'Elia Daniel Crespy VISTEC Advanced Laboratory for Environment-Related Inorganic and Organic Syntheses Department of Materials Science and EngineeringVidyasirimedhi Institute of Science and Technology21210Wang ChanRayongThailand Department of Materials Science and Engineering Vidyasirimedhi Institute of Science and Technology21210Wang ChanRayongThailand

Polyhydroxyur.thanes(PHUs)have received considerable attention in the last decade as potential alternatives to traditional phosgene-based polyur.thanes(PUs).The development of suitable 5CC(five membered-ring cyclic carbonate)precur.ors bearing multiple carbonate moieties(multi-5CCs)is a key requisite for preparing PHUs by polyaddition reaction with bis-or *** sustainable PHUs from CO_(2)-based five-membered cyclic carbonates(5CCs)obtained from biobased epoxides is a valuable strategy to bridge CO_(2) utilization and the upcycling of renewable *** this context,while many multi-5CC monomers reported in the literatur. are oil-based,recent efforts have led to the development of a large variety of multifunctional 5CCs that are produced by the combination of CO_(2) and renewable resour.es such as fatty acids and vegetable oils,lignin,terpenes,and *** this work,recent crucial advances(2019—2023)on PHUs prepared from bis-and multi-5CCs produced from CO_(2) and(partially/potentially)biobased substrates are reviewed with respect to their synthesis,thermal and mechanical properties,and their recent,emerging applications.

关键词： CO_(2) conversion Polyhydroxyur.thanes Cyclic carbonates Biobased compounds Fatty acids Functional polymers Monomers Renewable resour.es

Influence of waning immunity on vaccination decision-making:A multi-strain epidemic model with an evolutionary approach analyzing cost and efficacy

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Infectious Disease Modelling 2024年第3期9卷 657-672页

作者： Md.Mamun-ur.Rashid Khan Jun Tanimoto Interdisciplinary Graduate School of Engineering Sciences Kyushu UniversityKasuga-koenKasuga-shiFukuoka816-8580Japan Faculty of Engineering Sciences Kyushu UniversityKasuga-koenKasuga-shiFukuoka816-8580Japan Department of Mathematics University of DhakaDhaka1000Bangladesh

In this research,we introduce a comprehensive epidemiological model that accounts for multiple strains of an infectious disease and two distinct vaccination *** stands out as the most effective means to prevent and manage infectious ***,when there are various vaccines available,each with its costs and effectiveness,the decision-making process for individuals becomes ***,the factor of waning immunity following vaccination also plays a significant role in influencing these *** understand how individuals make decisions in the context of multiple strains and waning immunity,we employ a behavioral model,allowing an epidemiological model to be coupled with the dynamics of a decision-making *** base their choice of vaccination on factors such as the total number of infected individuals and the cost-effectiveness of the *** findings indicate that as waning immunity increases,people tend to prioritize vaccines with higher costs and greater ***,when more contagious strains are present,the equilibrium in vaccine adoption is reached more ***,we delve into the social dilemma inherent in our.model by quantifying the social efficiency deficit(SED)under various parameter combinations.

关键词： Multistrain epidemic model Vaccination Behavior dynamics Waning immunity Social dilemma

Influence of imidazolium ionic liquids as organic filler dispersant on electrical properties of chitin/epoxy composites

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High Voltage 2024年第4期9卷 930-938页

作者： Kai Yin Qihong Fan Jing Li Taqi ur.Rahman Tianyin Zhang Ashish Paramane Xiangrong Chen School of Information and Electrical Engineering Hangzhou City UniversityHangzhouChina College of Electrical Engineering Zhejiang UniversityHangzhouChina State Grid Tianjin Power Chengnan District Supply Company TianjinChina Electrical Engineering Department National Institute of TechnologySilcharAssamIndia

Ionic liquid(IL)as the dispersant can help disperse the organic nanofillers to improve the performance of epoxy resin ***,the effect of IL on the electrical properties of epoxy composites is not well *** comprehensive study consists of the preparation,material characterisation and systematical investigation of electrical properties of 1-Butyl-3-methylimidazole hexafluorophosphate-modified chitin fibre/epoxy *** findings show that introducing IL into a chitin/epoxy composite can minimise porosity defects and improve the compatibility between filler and ***,a high concentration of IL induces severe charge injection into chitin/epoxy composites and internal electric field *** addition of 0.75%–1.5%mass fraction IL results in maximum enhancement in the AC breakdown strength of the chitin/epoxy composite(by~71%)compared with the non-IL *** nonlinear conductivity and non-uniform charge injection phenomena of IL-modified composites can be attributed to the movement of radicals and anions due to the decomposition of *** this study,it is highly expected that the organic filler dispersion in the epoxy matrix can be optimised by tuning IL to improve the insulation properties.

关键词： composites composite filler

Volcanically Driven Terrestrial Environmental Pertur.ations dur.ng the Carnian Pluvial Episode in the Eastern Tethys

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 753-770页

作者： Naveed ur.RAHMAN XIAN Benzhong FANG Linhao CHEN Sirui CHEN Peng Zaheen ULLAH WANG Pengyu National Key Laboratory of Petroleum Resour.es and Engineering Beijing 102249China College of Geosciences China University of PetroleumBeijing 102249China Centre for Earth and Space Sciences University of SwatSwat 19120Pakistan

The Carnian Pluvial Episode(CPE)fingerprints global environmental pertur.ations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin dur.ng the CPE remains poorly *** of negative carbon isotopic excur.ions(NCIEs),mercur.(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial *** three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Eur.pe,the UK,and South and North *** U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun *** may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine *** records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP dur.ng the ***,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.

关键词： Chang 7 Member oil shale Carnian Pluvial Episode volcanism environmental pertur.ations