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Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of gdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： s.W.Wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil University

We investigated the emission properties of Eu3+-doped gdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped gdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in gdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped gdNbO4phosphors.

关键词： Eu 3+ gdNbO 4 Codoping of Li + Photoluminescence sensitizer Rare earths

What is the effect of Tribulus terrestris on testicular morphology and sperm production?An experimental study in the rat model

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Asian Journal of Andrology 2024年第1期26卷 67-70页

作者： Marcello Henrique Araujo Da silva gabriela Faria Buys-goncalves Joao Henrique Duque Reis Estrada Francisco Jose Barcellos sampaio Diogo Benchimol de souza Urogenital Research Unit Rio de Janeiro State UniversityRio de Janeiro 20551-030RJBrazil

The objective of this study was to investigate whether treatment with Tribulus terrestris(Tt)has any impact on the testicular morphology and function in a rodent *** male rats were divided into a control group and a group receiving 100 mg kg^(-1) body weight of Tt *** 4o days of experiment,the animals were submitted to euthanasia;epididymal tail spermatozoa were collected;and spermatozoa concentration,motility,and viability were *** addition,testicles were collected and processed for histomorphometrical *** were compared using the student's t-test and considered significant when Pshowed no difference between the ***,testicular weight and volume,seminiferous tubule diameter,tunica propria surface density,seminiferous epithelium surface density,and intertubular compartment surface density were statistically similar between the ***,seminiferous epithelium height and tubular lumen surface density were augmented in animals treated with *** with Tt does not cause a major impact on testicular morphology,promoting only subtle *** difference on spermatozoa parameters was observed.

关键词： morphometry testicle Tribulus terrestris

Development of an ultrathin liquid sheet target for laser ion acceleration at high repetition rates in the kilohertz range

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High Power Laser science and Engineering 2024年第3期12卷 134-145页

作者： M.Füle A.P.Kovács T.gilinger M.Karnok P.gaál s.Figul g.Marowsky K.Osvay National Laser-Initiated Transmutation Laboratory University of SzegedSzegedHungary Department of Experimental Physics University of SzegedSzegedHungary ELI ALPs ELI-HU Non-Profit Ltd.SzegedHungary Department of Optics and Quantum Electronics University of SzegedSzegedHungary Advanced Microfluidic systems gmbH GöttingenGermany

A colliding microjet liquid sheet target system was developed and tested for pairs of round nozzles of 10,11 and 18μm in *** sheet's position stability was found to be better than a few *** interaction with 50 mJ laser pulses,the 18μm jet has a resonance amplitude of 16μm at a repetition rate of 33 Hz,while towards 100 Hz it converges to 10μm for all nozzles.A white-light interferometric system was developed to measure the liquid sheet thickness in the target chamber both in air and in vacuum,with a measurement range of 182 nm±1μm and an accuracy of±3%.The overall shape and 3D shape of the sheet follow the Hasson±Peck model in *** vacuum versus air,the sheet gradually loses 10%of its thickness,so the thinnest sheet achieved was below 200 nm at a vacuum level of 10±4mbar,and remained stable for several hours of operation.

关键词： diagnostics laser ion acceleration nanometric liquid sheet targets vacuum test

A Preliminary Comparative study on the Centering Algorithms for CassiniIss NAC Images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.Liang Q.-F.Zhang g.-M.Liu W.-H.Zhu C.-s.Wang Department of Computer science Jinan UniversityGuangzhou 510632China sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China school of Computer science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow Angle Camera(NAC)of the Cassini Imaging science subsystem(Iss).selecting the best centering algorithm is key to enhancing astrometric *** this study,we compared the accuracy of five centering algorithms:gaussian fitting,the modified moments method,and three point-spread function(PsF)fitting methods(effective PsF(ePsF),PsFEx,and extended PsF(x PsF)from the Cassini Imaging Central Laboratory for Operations(CICLOPs)).We assessed these algorithms using 70 Iss NAC star field images taken with CL1 and CL2 filters across different stellar *** ePsF method consistently demonstrated the highest accuracy,achieving precision below 0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PsF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPsF model provided by CICLOPs had lower precision than the ***,the ePsF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPsF focusing on photometry rather than *** findings highlight the necessity of constructing PsF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these Iss NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

The magnetosheath at high spectral resolution

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Earth and Planetary Physics 2024年第1期8卷 234-246页

作者： K.D.Küntz D.Koutroumpa W.R.Dunn A.Foster F.s.Porter D.g.sibeck B.Walsh The Henry A.Rowland Department of Physics and Astronomy Johns Hopkins University3701 San Martin DriveBaltimoreMD21218USA NAsA goddard space Flight Center 8800 Greenbelt RoadGreenbeltMD 20771USA LATMOs-OVsQ CNRSUVSQ Paris-SaclaySorbonne Université11 Boulevard d’Alembert78280GuyancourtFrance Department of Physics and Astronomy University College LondonLondonUK The Centre for Planetary science at UCL/Birkbeck Gower StreetLondon WC1E 6BTUK Center for Astrophysics Harvard University&Smithsonian Institution60 Garden StreetCambridgeMA 02138USA Center for space Physics Boston University110 Cummington MallBostonMAUSA

While we eagerly anticipate sMILE’s(solar wind Magnetosphere Ionosphere Link Explorer)unprecedented X-ray observations of the Earth’s magnetosheath and the initiation of a new era of magnetospheric research,it seems appropriate to look ahead to the abilities of the next generation of astrophysics *** these,the Line Emission Mapper(LEM),a large aperture micro-calorimeter based mission,is currently planned to be able to observe the magnetosheath at high spectral resolution(~2 eV).With a field of view of~30′,LEM will allow higher spatial resolution and higher cadence measurement of the motion of a very small portion of the magnetopause over relatively short periods of time(multiple hours),complementing sMILE’s global ***’s strength is its spectral *** will be able to measure the abundance of a broad range of elements and ionization states,many of which are inaccessible to current in situ instruments,and will be able to separate the emission from the magnetosheath from the emission from the cosmic X-ray background using the difference in their relative velocities.

关键词： magnetosheath charge exchange solar wind abundances

Plasma electrolytic formation and characterization of MnWO_(4)/WO_(3) film heterostructures

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ChemPhysMater

ChemPhysMater 2024年第3期3卷 293-302页

作者： M.s.Vasilyeva I.V.Lukiyanchuk Yu.B.Budnikova V.g.Kuryavyi D.H.shlyk g.A.Zverev Department of Chemistry and Materials of Institute of High Technology and Advanced Materials Far Eastern Federal UniversityFEFU CampusVladivostok 690922Russia Institute of Chemistry Far Eastern BranchRussian Academy of SciencesVladivostok 690022Russia

MnWO_(4)/WO_(3) p-n heterojunction films were fabricated using a one-step method consisting of the plasma electrolytic oxidation(PEO)of titanium in homogeneous electrolytes containing paratungstate ions and stable watersoluble EDTA-chelated *** influences of the formation current density and W:Mn molar ratio of the electrolyte,which was varied from 1:2 to 2:1,on the composition,morphology,and optical and photocatalytic properties of the resulting coatings were studied.X-ray diffraction analysis,scanning electron microscopy,energy dispersive X-ray analysis,Raman spectroscopy,and ultraviolet diffuse reflectance spectroscopy were used to characterize the formed *** of the W:Mn ratio of the electrolyte,the coatings contained crystalline t-WO_(3) and m-MnWO_(4).Depending on the formation conditions,the optical band gap energies of the composites varied from 2.63 to 3.01 *** largest absorption red shift and lowest band gap energy were observed in the film composite formed in an electrolyte with W:Mn=2:1,at a current density of 0.2 A cm^(−2).Composites obtained in electrolytes with W:Mn ratios of 2:1 and 1:1 exhibited photocatalytic activity in the degradation of rhodamine C and methyl orange dyes in the presence of 10 mmol L^(–1) H2O_(2) under ultraviolet and visible light *** role of hydrogen peroxide in this dye degradation on PEO-coated composites under light irradiation is discussed.

关键词： Plasma electrolytic oxidation Manganese tungstate Tungsten oxide Titanium Optical properties p-n heterojunction

How far have we come? Review of main public policies to reduce landslide impacts in Brazil

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Journal of Mountain science 2024年第09期 2891-2904页

作者： Bianca Carvalho VIEIRA Tiago Damas MARTINs Telma Mendes da silva José Eduardo BONINI Department of geography University of S?o Paulo Cities Institute Federal University of S?o Paulo Department of geography Federal University of Rio de Janeiro

During the rainy season in Brazil, landslides can have catastrophic consequences, including loss of life, damage to urban infrastructure and significant economic impacts. Now, more than eight million people in Brazil live in disaster-prone areas. The objective of this article is to present a chronological review of the principal policies and programmes at the national, state, and municipal levels, with an emphasis on their key actions aimed at mitigating the impact of disasters related to natural hazards, particularly landslides. Our analysis was based on official records of public policies from the national, state, and municipal governments. The results show that several initiatives were initially developed at the local and regional level. However, it was not until the late 1980s that a comprehensive organisation of civil protection at the national level emerged as a response measure. It is possible to highlight three phases(understanding, coexistence, and prevention) of institutional action focused on risk management in the face of disasters. Despite the growing knowledge of risk scenarios, disasters continue to occur in Brazil on an annual basis, revealing several obstacles to reducing their impact,particularly given the social and economic disparities between Brazilian regions and the applicability of public policies that must overcome the limitations of each municipality.

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First evidence for chiral wobbling of triaxial nuclei

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Nuclear science and Techniques 2024年第7期35卷 4-7页

作者： s.Frauendorf Department of Physics and Astronomy University of Notre DameNotre DameIN 46556USA

Chirality(greek“handiness”)is a property of many com-plex *** molecules exist in two forms,one being the mirror image of the *** for our hands,it is impossible to make the images identical by a suitable *** two forms are called left-handed and *** have the same binding energy,because the electro-magnetic interaction,which holds the molecule together,does not change under a *** properties that are insensitive to the geometry are also the *** different geometry is the reason why the left-handed form turns the polarization plane of transmitted light in one direction by some angle while the right-handed form turns it in the oppo-site direction by the same ***,the geometrical differences between the two species may have other *** two species of the carvon molecule shown in Fig.1 taste quite differently.

关键词： turns Chiral mirror

Tribological behavior of lubricant-impregnated porous polyimide

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Friction 2024年第4期12卷 711-725页

作者： Jinbang LI Ningning ZHOU Janet s.s.WONg school of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is *** this work,three porous polyimides(PPI)with different densities were ***(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire *** operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around *** at the outlet is created at high sliding *** amount of released oil increases with increasing PPI *** moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load *** higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with *** high density PPIs,high speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil *** of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI *** low-and medium-density(highly porous,high roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological *** high density(low porosity)PPI,with lower roughness,hydrodynamic lubrication is achieved which gives the lowest *** results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication