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Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol-gel technique

Particuology 2018年第5期16卷 141-151页

作者： A.H.Ashour Ahmed i.e1-Batal M.i.A.Abdel Maksoud Gharieb S.el-Sayyad Sh.Labib e.Abdeltwab M.M.el-Okr Materials Science Laboratory Radiation Physics Department.National Center for Radiation Research and TechnologyAtomic Energy AuthorityCairoEgypt Drug Microbiology Laboratory Drug Radiation Research DepartmentNational Center for Radiation Research and TechnologyAtomic Energy Authority CairoEgypt Nuclear Chemistry Department Hot Laboratories CenterAtomic Energy AuthorityCairoEgypt Physics Department Faculty of Science (Girls Branch)Al-Azhar UniversityCairo.Egypt Physics Department.Faculty of Science (Boys Branch) Al-Azhar UniversityCairoEgypt

Metal-substituted cobalt ferrites [MxCo(1-x)Fe2O4(M=Zn,Cu,Mn;x=0.0,0.25,0.5,and 0.75)]were synthesized via a sol-gel *** ferrite structures were confirmed by X-ray diffraction, Fourier transform infrared spectroscopy,scanning electron microscopy,surface analysis using the Brunauer-emmett-Teller method,and energy-dispersive X-ray *** activity of these ferrites against selected pathogenic microbes was *** structures remained cubic spinel phases after substitution of *** strongly influenced the microstructure and homoge- neous grain *** particle size of the ferrites increased linearly with increase in their annealing *** surface area of zinc cobalt ferrite nanoparticles (ZCFO)was 52.56m^2/g,the average pore size was 1.84nm,and pore volume was 0.136mL/*** ferrites showed antimicrobial activity toward all pathogens *** these,the most powerful was ZCFO,showing zones of inhibition of 13.0mm against Bacillus subtilis and Staphylococcus aureus and 12.0mm against Candida ***-irradiated ZCFO nanoparticles (150.0kGy)maintained higher antimicrobial activity than non-irradiated particles,e.g. being active toward *** (16.0mm).ZCFO is proposed as a candidate material for industrial and biomedical purposes.

关键词： Antibacterial Antifungal Zone of inhibition Zinc cobalt ferrite nanoparticles Gamma irradiation

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Chirping instabilities produced by a runaway electron beam at a spherical tokamak

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Plasma Science and Technology 2023年第7期25卷 19-24页

作者： i M BALACHeNKOV N N BAKHAReV V K GUSeV M V iLiASOVA e M KHiLKeViCH P S KOReNeV A e KONKOV V B MiNAeV Yu V MiTRiZHKiN M i PATROV Yu V PeTROV N V SAKHAROV A e SHeVeLeV O M SKReKeL ioffe institute Saint-Petersburg 194021Russia Lomonosov Moscow State University Moscow 119991Russia

Two different types of MHD instabilities with rapidly chirping frequency were found to arise in the Globus-M2 spherical tokamak in substantially different frequency *** first type arises at frequencies of an order of 1 MHz in ohmic plasmas at relatively low density(n_(e))in a wide range of toroidal magnetic fields and plasma *** type of instability was identified as compressional Alfven waves,driven by electrons,accelerated during a sawtooth *** was found that the mode frequency is sweeping in time,according to the Berk-Breizman hole-clump nonlinear chirping *** second type of wave arises in a specific single-swing regime of the central solenoid current with a very narrow plasma column,when the plasma tends to decay at extremely low density(n_(e))in fact,is an instability of the runaway electron *** exited modes cover the whole observed frequency range and are divided into several(two or three)frequency regions:approximately 0-30 MHz,60-120 MHz and sometimes 30-60 *** of the branches was also *** chirps are more rapid than for 1 MHz Alfven instability and follow an exponential *** paper,to our knowledge,is the first report of frequency chirping instabilities excited by accelerated electrons at a spherical tokamak.

关键词： Alfvén waves chirping instability spherical tokamak runaway electrons

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Numerical analysis of fluid flow dynamics around a yawed half-submerged cylinder inside an open channel

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Journal of Hydrodynamics 2021年第1期33卷 111-119页

作者： M.i.Alamayreh A.Fenocchi G.Petaccia S.Sibilla e.Persi Alternative energy Department Al-Zaytoonah University of JordanJordanAmman Department of Civil engineering and Architecture University of PaviaPaviaItaly

The drag and side force coefficients of a half-submerged cylinder in a free-surface flow were calculated through numerical simulations,with the aim of supporting the numerical modelling of log transport in *** variability of these coefficients with the yaw angle with respect to the flow direction and with the ratio between the flow depth and the diameter of the cylinder were *** were performed with the three-dimensional code ANSYS/CFX,employing the volume of fluid multiphase technique to reproduce the critical interaction between the free surface and the *** numerical tests,showing the rise of the drag force coefficient for increasing yaw angles passing from flow-parallel to flow-perpendicular cylinder and the peak of the side force coefficient for flow-oblique cylinder,were validated by comparison with the results of laboratory *** simulations were then extended to conditions with significant blockage in the vertical direction which had not been previously experimented,revealing a strong increase in the force coefficients for decreasing ratios between the flow depth and the cylinder diameter.A detailed description of the reproduced flow features in the proximity of the cylinder for the different cases was furthermore *** report,in addition to the analysis of the force coefficients,could serve a much wider range than that of log transport,i.e.,any case in which a floating cylinder interacts with free-surface flow.

关键词： Large woody debris(LWD)transport floating objects drag and side force coefficients vertical blockage free-surface interaction

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Degradation of indomethacin in river water under stress and non-stress laboratory conditions:degradation products,long-term evolution and adsorption to sediment

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Journal of environmental Sciences 2017年第1期29卷 13-20页

作者： Juan J.Jimenez Maria i.Sanchez Rafael Pardo Beatriz e.Munoz Department of Analytical Chemistry Faculty of SciencesCampus Miguel DelibesUniversity of ValladolidPaseo de Belen 747012 ValladolidSpain i.U.CiNQUiMA Campus Miguel DelibesUniversity of ValladolidPaseo de Belen 547011 ValladolidSpain Department of Analytical Chemistry School of Industrial EngineersUniversity of ValladoliclFrancisco Mendizdbal 147014 ValladolidSpain

The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants,whose effluents flow into aquatic environments;concentrations in the 0.1-100 ng/L range are commonly found in surface waters,and its fate is ***,biological,photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over *** results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin（2 μg/L） in less than 6 hr,but indomethacin was detected over a period of 4 months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited,as occurs inside a body of *** biological degradation in water was negligible,while the hydrolysis at pH 7.8 was *** were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction,and six degradation products were found;their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra.4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products,persisting for at least 30 weeks in water kept under non-stress ***,the degradation in the presence of sediment was also monitored over time,with some differences being *** adsorption coefficients of indomethacin and degradation products on river sediment were calculated;long-term degradation products did not have significant adsorption to sediment.

关键词： indomethacin Degradation products River water Adsorption coefficients High-resolution mass spectrometry

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Physicochemical regeneration of high silica zeolite Y used to clean-up water polluted with sulfonamide antibiotics

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Journal of environmental Sciences 2016年第5期28卷 302-312页

作者： i.Braschi S.Blasioli e.Buscaroli D.Montecchio A.Martucci Department of Agricultural Sciences University of Bologna NanoSiSTeMi interdisciplinary Centre Università del Piemonte Orientale A.Avogadro Department of Physics and earth Sciences University of Ferrara

High silica zeolite Y has been positively evaluated to clean-up water polluted with sulfonamides, an antibiotic family which is known to be involved in the antibiotic resistance evolution. To define possible strategies for the exhausted zeolite regeneration,the efficacy of some chemico-physical treatments on the zeolite loaded with four different sulfonamides was evaluated. The evolution of photolysis, Fenton-like reaction, thermal treatments, and solvent extractions and the occurrence in the zeolite pores of organic residues eventually entrapped was elucidated by a combined thermogravimetric（TGA–DTA）, diffractometric（XRPD）, and spectroscopic（FT-iR） approach. The chemical processes were not able to remove the organic guest from zeolite pores and a limited transformation on embedded molecules was observed. On the contrary, both thermal treatment and solvent extraction succeeded in the regeneration of the zeolite loaded from deionized and natural fresh water. The recyclability of regenerated zeolite was evaluated over several adsorption/regeneration cycles, due to the treatment efficacy and its stability as well as the ability to regain the structural features of the unloaded material.

关键词： Zeolite recyclability Water depollution Sulfa drugs Thermal regeneration Solvent extraction

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effects of V and Cr Addition on the Structural and Sensing Properties of Titania

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稀有金属材料与工程 2006年第A3期35卷 113-115页

作者： e.Comini i.Alessandri G.Faglia e.Bontempi L.e.Depero G.Sberveglieri Sensor Laboratory INFMUniversita'di Brescia25133 BRESCIAItaly Laboratorio di Chimica perle Tecnoiogie Universita'di Brescia25133 BRESCIAItaly

We have comparatively studied the addition of Cr and V in *** and V content were changed by means of insets placed in the Ti ***,compositional and electrical analyses of different series of thin films,made by XRF, XRD,are *** characterization not only showed that Cr doped layers were very sensitive to ethanol within a useful range for applications,but also allowed to verify that the electrical behaviour is dependent on the structure of film. Finally,the Cr and V concentrations that gives the best results in terms of sensing performances has been determined and a correlation between structural and electrical measurement has been evidenced.

关键词： titania V Cr ethanol sensors thin films

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effect of Crystallization Conditions on Polymorphic Diversity of Malic Acid RS-Racemate

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Transactions of Tianjin University 2013年第2期19卷 86-91页

作者： isakov A i Kotelnikova e N Kryuchkova L Yu Lorenz H St.Petersburg State University St.Petersburg 199034Russia Max Planck institute for Dynamics of Complex Technical Systems Magdeburg 39106Germany

enantiomers （R （＋） and S（-））, RS-racemate mixture of enantiomers） of malic acid C4H605 have been （double compound） and （R ＋ S） -conglomerate （mechanical investigated by means of X-ray diffractometry and high tern- perature X-ray diffraction method. The RS-racemate was found to be able to form three polymorphic modifications, which we denominated as M1 （monoclinic, space group P21/c）, M2 （monoclinic, space group Cc）, and Tc （triclinic, space group P-l ）, the latter modification having been unknown before. Modification Tc was also described, and its X- ray diffraction characteristics, including interplanar spacings d, hkl indices, unit cell parameters, were defined. in addi- tion, X-ray diffraction characteristics for both reported earlier M1 and M2 monoclinic polymorphic modifications were measured with higher accuracy. The ability of RS-racemate to form one of the above three modifications （Mi, M2, and Tc） or their mixtures containing various proportions and combinations of the components （M1 ＋ M2, M1 ＋ Tc, or M2 ＋ Tc） was found to depend on the type of crystallization medium （a melt, aqueous medium, ethanol or acetone solu- tion）, crystallization rate （from 2--3 minutes to 4 months）, and crystallization temperature. Heating S-enantiomer and M1 RS-racemate up to their respective melting points （100 ℃ and 124 ℃, correspondingly） only made them undergo thermal deformations, while heating （R ＋ S） -conglomerate in the temperature range of 96--110 ℃ resulted in its homogenization to form M2 RS-racemate, which, near the melting point （118 ℃）, namely, in the range of 112-116 ℃, was transformed into Mi RS-racemate. Keywords： polvmorDhism; racemic, chiral

关键词： polymorphism racemic chiral

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LiMiT CYCLeS AND iNVARiANT PARABOLA iN A KUKLeS SYSTeM OF DeGRee THRee

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Acta Mathematica Scientia 2008年第4期28卷 865-869页

作者：刘振海 e.Sáez i.Szántó Department of Mathematics Changsha University of Sciences and Techndogy Departamento de Matemática Universidad Tcnica Federico Santa MariaCasilla 110-VValparaisoChile

in this article,the authors consider a class of Kukles planar polynomial differential system of degree three having an invariant *** this class of second-order differential systems,it is shown that for certain values of the parameters the invariant parabola coexists with a *** other values it can coexist with one,two or three small amplitude limit cycles which are constructed by Hopf *** result gives an answer for the question given in[4],about the existence of limit cycles for such class of system.

关键词： Kukles system limit cycles invariant algebraic curves

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Climate variation, reproductive frequency and acorn yield in english Oaks

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Journal of Plant ecology 2019年第3期12卷 542-549页

作者： Mick e.Hanley Benjamin i.Cook Michael Fenner School of Biological and Marine Sciences University of PlymouthPlymouthUK NASA Goddard institute for Space Studies New YorkNYUSA Ocean and Climate Physics Lamont-Doherty Earth ObservatoryPalisadesNYUSA Centre for Biological Sciences University of SouthamptonSouthamptonUK

Aims Annually variable but synchronous production of large seed crops(‘masting’)is a widespread phenomenon in temperate *** concerns about the impacts of anthropogenic climate change(ACC)on plant reproduction gives urgency to our need to understand better the role of climate on tree reproduction,and in particular,mast *** our understanding of reproductive phenology however,there is little consensus regarding how climate affects plant reproductive effort or indeed the actual environmental triggers that underpin masting *** We used a 27-year record of acorn yield from a population of 12 Quercus robur trees located in southern england to compare mast-ing frequency and post-dispersal acorn yield each year for each tree,with long-term weather data over the same *** focussed on discrete or sequential climate cues(temperature,precipitation and frost days)as likely predictors of oak *** Findings Annual post-dispersal acorn crop varied greatly;*** acorns in 14 of the 27 years,but there was no sequential pattern of crop ver-sus non-crop years indicating that weather,rather than resource limitation alone,dictated the timing of *** years were instead most closely associated with relatively cool late sum-mer conditions in the preceding year,followed by anomalous sum-mer warmth within crop *** yield increased following dry April and above-average May and June temperatures within crop *** our results support a general association between warm late spring and summer conditions,and crop frequency and yield,respectively,the influence of cooler later summer conditions in the year prior to masting highlights how a combination of weather cues may dictate the occurrence of mast ***,our results corroborate not only the hypothesis that temperature differ-entials between consecutive years,not absolute temperatures,may be the better predictor of mast seeding events but lend support al

关键词： anthropogenic climate change environmental veto Moran effect Quercus robur reproductive effort

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Tree regeneration in gap-understory mosaics in a subtropical Shorea robusta(Sal) forest

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Journal of Forestry Research 2019年第6期30卷 2061-2068页

作者： L.N.Sharma K.B.Shrestha i.e.Maren Forest Action Nepal GPO-12207 LalitpurNepal Department of Biological Sciences University of BergenThormoensgate 53B5007 BergenNorway

Spatial variation in tree-regeneration density is attributed to the specialization of tree species to light availability for germination and *** availability,in turn,varies across the gap-understorey *** gaps provide an important habitat for the regeneration of tree species that would otherwise be suppressed in the *** subtropical forests,there is still a knowledge-gap relating to how canopy disturbances influence tree-regeneration patterns at local scale,and if they disproportionately favor regeneration of certain *** aim to analyze whether canopy gaps promote tree regeneration,and tree species are specialized to gaps or understory for germination and *** sampled vegetation in 128 plots(0.01 ha),equally distributed in gaps and below canopy,in two subtropical Shorea robusta Gaertn.(Sal)forests in Nepal,recording the number of tree seedlings and saplings in each *** compared the regeneration density of seedlings and saplings separately between gaps and the *** mean densities of seedlings and saplings were higher in the gaps at both sites;although there was no difference in the seedling density of the majority of the species between the *** species were confined to either gap or understorey at the seedling *** conclude that gaps are not critical for the germination of tree species in Sal forests but these are an important habitat for enabling seedlings to survive into *** classification of trees into regeneration guilds mainly based on germination does not apply to the majority of tree species in subtropical Sal *** results reaffirm that gap creation promotes tree regeneration by favouring seedling survival and growth and can influence forest management for conservation,as well as for plantations.

关键词： Canopy-gap Density Regeneration Saplings Seedlings Shade tolerance

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