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Analysis of the Impact of the Blazhko Effect Both on the Van Hoof Effect and Radial Velocity Amplitude in the Star RR Lyr

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Research in Astronomy and Astrophysics 2024年第6期24卷 253-272页

作者： Y.El jariri f.L.Sefyani A.Benhida Z.Benkhaldoun K.Kolenberg K.Chafouai A.Habib M.Sabil Observatoire de l'Oukaimeden LPHEAFSSMUniversitéCadi AyyadMarrakech2390Morocco Observatoire de l'Oukaimeden LPHEAFSTGUniversitéCadi AyyadMarrakech549Morocco Département de physique Universitéd'Anvers Avenue Groenenborger 171Anvers2020Belgium LICPM ENSA-BMUniversitéSultan Moulay SlimaneBeni-Mellal23020Morocco

The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating *** this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR Lyr of RR Lyrae stars recorded for 22 *** based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,france)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(Morocco)between 2015 and *** this study,we have detected information on atmospheric dynamics that had not previously been ***,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as *** the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of feⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko ***,we found that the Van Hoof effect is also modulated by the Blazhko ***,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is *** also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper *** observed over a long time,we can interpret it as a function of the Blazhko phases.

关键词： stars:atmospheres stars:variables:RR Lyrae shock waves techniques:spectroscopic techniques:radial velocities stars:individual(RR Lyr)

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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

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Assessment of the piroxicam-incited model of synchronized colitis in T-cell receptor alpha chain-deficient mice

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Animal Models and Experimental Medicine 2024年第4期7卷 533-543页

作者： Maximo E.Lange Danisa M.Bescucci Valerie f.Boras Tony Montina G.Douglas Inglis douglas inglis 11 lethbridge research and development centre agriculture and agri-food canadalethbridgealbertacanada alberta health services chinook regional hospitallethbridgealbertacanada department of chemistry and biochemistry university of lethbridgelethbridgealbertacanada southern alberta genome sciences centre university of lethbridgelethbridgealbertacanada

Background:A multitude of mouse models are utilized to emulate and study intestinal inflammation.T-cell receptor alpha chain(TCRα)-deficient mice are used as a model of spontaneous colitis that has similarities with human ulcerative ***,colitis is triggered late in the life of the mouse(age:4-5 months),and inflammation does not develop at the same time in different mice.A previously conducted study reported that the administration of the drug piroxicam triggered predictable and early colitis in TCRα-deficient mice at the age of 6-8 ***,a detailed characterization of ensuing inflammation was not ***:We conducted an in-depth examination of piroxicam-triggered colitis in TCRα-deficient mice,with emphasis on spatial histopathologic changes and analysis of expression of inflammatory ***,we tested amelioration of colitis with ***:We confirmed that piroxicam induced a time-prescribed colitis and did so in the proximal colon as well as the cecum of TCRα-deficient *** adminis-tration was observed to induce epithelial hyperplasia,goblet cell loss,and leukocyte infiltration with occasional ulceration.A Swiss roll technique was used to examine the colon and cecum in its ***,we observed that inflammation was mul-tifocal segmental,with areas of tissue damage in between healthy *** addition,we observed variability in the severity of inflammation among replicate animals and treatments,and that the administration of dexamethasone only partially ameliorated inflammation in the proximal ***:Piroxicam consistently induced multifocal segmental colitis in the proxi-mal colon and cecum,although the degree of inflammation was reduced in the ***,spatial variability in inflammation in the large intestine and the inter-replicate variation in the severity of inflammation must be taken into consideration when utilizing this murine model of synchronized colitis.

关键词： colon dexamethasone histology induction inflammation knockout

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Mitigating Urban Heat Island Effects: A Review of Innovative Pavement Technologies and Integrated Solutions

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Structural Durability & Health Monitoring 2024年第5期18卷 525-551页

作者： S.f.Ismael A.H.Alias N.A.Haron B.B.Zaidan Abdulrahman M.Abdulghani Department of Civil Engineering Faculty of EngineeringUniversiti Putra MalaysiaSerdang43400Malaysia Central Region Heavy Civil DivisionGranite ConstructionWoodlandsTexas77381USA SP Jain School of Global Management LidcombeSydneyNSW2141Australia Department of Communication Technology and Network Faculty of Computer Science and Information TechnologyUniversiti Putra MalaysiaSerdang43400Malaysia

In this review paper,we present a thorough investigation into the role of pavement technologies in advancing urban *** analysis traverses the historical evolution of these technologies,meticulously evaluating their socio-economic and environmental impacts,with a particular emphasis on their role in mitigating the urban heat island *** evaluation of pavement types and variables inﬂuencing pavement performance to be used in the multi-criteria decision-making(MCDM)framework to choose the optimal pavement application are at the heart of our *** serves to assess a spectrum of pavement options,revealing insights into the most effective and sustainable *** highlighting both the existing challenges and potential innovative solutions within theﬁeld,this paper aims to offer a directional compass for future urban planning and infrastructural *** review not only synthesizes the current state of knowledge but also aims to chart a course for future exploration,emphasizing the critical need for innovative and environmentally sensitive pavement tech-nologies in the creation of resilient and sustainable urban environments.

关键词： Pavement sustainability urban heat island environmental impact of pavements innovative pavement solutions economic and social implications sustainable development in urban areas

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factors affecting the direct mineralization of CO_2 with olivine

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Journal of Environmental Sciences 2011年第8期23卷 1233-1239页

作者： Soonchul Kwon Maohong fan Herbert f. M. DaCosta Armistead G. russell School of Civil and Environmental Engineering Georgia Institute of Technology Department of Chemical and petroleum Engineering University of Wyoming Caterpillar Inc. P.O. Box 1875 Peoria Illinois 61656 USA

Olivine, one of the most abundant minerals existing in nature, is explored as a C02 carbonation agent for direct carbonation of C02 in flue gas. Olivine based C02 capture is thermodynamically favorable and can form a stable carbonate for long-term storage. Experimental results have shown that water vapor plays an important role in improving CO/carbonation rate and capacities. Other operation conditions including reaction temperature, initial C02 concentration, residence time corresponding to the flow rate of C02 gas stream, and water vapor concentration also considerably affect the performance of the technology.

关键词： carbon dioxide mineralization flue gas carbonation

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Melting of hydrous pyroxenites with alkali amphiboles in the continental mantle:*** element compositions of melts and minerals

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Geoscience frontiers 2024年第1期15卷 50-68页

作者： Stephen f.foley Isra S.Ezad School of Natural Sciences Macquarie UniversityNorth RydeNew South Wales 2109Australia Research School of Earth Sciences Australian National UniversityCanberraACT 2601Australia

The trace element compositions of melts and minerals from high-pressure experiments on hydrous pyroxenites containing K-richterite are presented. The experiments used mixtures of a third each of the natural minerals clinopyroxene, phlogopite and K-richterite, some with the addition of 5% of an accessory phase ilmenite, rutile or apatite. Although the major element compositions of melts resemble natural lamproites, the trace element contents of most trace elements from the three-mineral mixture are much lower than in lamproites. Apatite is required in the source to provide high abundances of the rare earth elements, and either rutile and/or ilmenite is required to provide the high field strength elements Ti, Nb, Ta, Zr and Hf. Phlogopite controls the high levels of Rb, Cs and *** abundances of trace elements in the various starting mixtures vary strongly because of the use of natural minerals, we calculated mineral/melt partition coefficients (DMin/melt) using mineral modes and melting reactions and present trace element patterns for different degrees of partial melting of hydrous pyroxenites. Rb, Cs and Ba are compatible in phlogopite and the partition coefficient ratio phlogopite/K-richterite is high for Ba (136) and Rb (12). All melts have low contents of most of the first row transition elements, particularly Ni and Cu ((0.1-0.01)×primitive mantle). Nickel has high DMin/melt for all the major minerals (12 for K-richterite, 9.2 for phlogopite and 5.6 for Cpx) and so behaves at least as compatibly as in melting of peridotites. fluorine/chlorine ratios in melts are high and DMin/melt for fluorine decreases in the order apatite (2.2) > phlogopite (1.5) > K-richterite (0.87). The requirement for apatite and at least one Ti-oxide in the source of natural lamproites holds for mica pyroxenites that lack K-richterite. The results are used to model isotopic ageing in hydrous pyroxenite source rocks: phlogopite controls Sr isotopes, so that lamproites with relatively l

关键词： Hydrous pyroxenite Lamproite Trace elements Phlogopite K-richterite Apatite

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Transformer for the Design of Automatic Control Systems with Prefilters

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World Journal of Engineering and Technology 2024年第3期12卷 575-586页

作者： Isaac Hughes John f. O’Brien Department of Electrical Engineering and Computer Science University of Wyoming Laramie USA

A machine learning model, using the transformer architecture, is used to design a feedback compensator and prefilter for various simulated plants. The output of the transformer is a sequence of compensator and prefilter parameters. The compensator and prefilter are linear models, preserving the ability to analyze the system with linear control theory. The input to the network is a window of recent reference and output samples. The goal of the transformer is to minimize tracking error at each time step. The plants under consideration range from simple to challenging. The more difficult plants contain closely spaced, lightly damped, complex conjugate pairs of poles and zeros. Results are compared to PID controllers tuned for a similar crossover frequency and optimal phase margin. for simple plants, the transformer converges to solutions which overly rely on the prefilter, neglecting the maximization of negative feedback. for more complex plants, the transformer designs a compensator and prefilter with more desirable qualities. In all cases, the transformer can start with random model parameters and modify them to minimize tracking error on the step reference.

关键词： feedback Machine Learning Compensator Design

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氮碳包封fe_(3)C纳米颗粒作为高效富氧还原电催化剂

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Science China Materials 2024年第3期67卷 762-770页

作者：汪翠萍李智雷杰李松 Stijn f.L.Mertens 胡劲松 School of Chemical Engineering Anhui Province Key Laboratory of Specialty PolymersAnhui University of Science and TechnologyHuainan 232001China Department of Chemistry Energy Lancaster and Materials Science LancasterLancaster UniversityLancaster LA14YBUnited Kingdom Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China

高活性MOf基催化剂的设计和合成为促进动力学不利的氧还原反应(ORR)过程开辟了新的途径.本研究通过在ZIf-8前驱体表面涂覆二茂铁甲酸,然后进行两步炭化工艺,设计和制备了一种具有新型结构的高效电催化剂,以提高ORR性能.两步炭化过程对... 详细信息

高活性MOf基催化剂的设计和合成为促进动力学不利的氧还原反应(ORR)过程开辟了新的途径.本研究通过在ZIf-8前驱体表面涂覆二茂铁甲酸,然后进行两步炭化工艺,设计和制备了一种具有新型结构的高效电催化剂,以提高ORR性能.两步炭化过程对于将热解fe_(3)C纳米颗粒封装到碳纳米管(CNTs)中以及将fe单原子隔离到N掺杂碳(NC)基体上至关重要.此外,fe元素的相对含量对优化催化剂的ORR性能至关重要.所制得fe_(3)C@CNTs/NC-M催化剂结构先进,在碱性溶液中表现出良好的长期稳定性和电催化ORR性能,其半波电位和极限电流分别达到0.941 V和6.31 mA cm^(-2).此外,该电催化剂在甲醇溶液中具有较强的耐受性和良好的稳定性.fe_(3)C@CNTs/NC-M锌空气电池(ZAB)具有1.525 V的开路电位,420 mA cm^(-2)时的峰值功率密度为348 mW cm^(-2),10 mA cm^(-2)时的最大容量为843 mA h g_(Zn)^(-1).因此,这种合成策略为构建具有有效和稳定的ORR性能的MOf基电催化材料提供了一条有效途径.

关键词： metal-organic frameworks carbon nanotubes N-doped carbon matrix oxygen reduction reaction Zn-air battery

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A Hybrid Cybersecurity Algorithm for Digital Image Transmission over Advanced Communication Channel Models

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Computers, Materials & Continua 2024年第4期79卷 201-241页

作者： Naglaa f.Soliman fatma E.fadl-Allah Walid El-Shafai Mahmoud I.Aly Maali Alabdulhafith fathi E.Abd El-Samie Department of Information Technology College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Electronics and Communications Faculty of EngineeringZagazig UniversityZagazig44519Egypt Security Engineering Lab Computer Science DepartmentPrince Sultan UniversityRiyadh11586Saudi Arabia Department of Electronics and Electrical Communications Engineering Faculty of Electronic EngineeringMenoufia UniversityMenouf32952Egypt

The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia ***-quality images require well-tuned communication *** Single Carrier frequency Division Multiple Access(SC-fDMA)is adopted for broadband wireless communications,because of its low sensitivity to carrier frequency offsets and low Peak-to-Average Power Ratio(PAPR).Data transmission through open-channel networks requires much concentration on security,reliability,and *** data need a space away fromunauthorized access,modification,or *** requirements are to be fulfilled by digital image watermarking and *** paper ismainly concerned with secure image communication over the wireless SC-fDMA systemas an adopted communication *** introduces a robust image communication framework over SC-fDMA that comprises digital image watermarking and encryption to improve image security,while maintaining a high-quality reconstruction of images at the receiver *** proposed framework allows image watermarking based on the Discrete Cosine Transform(DCT)merged with the Singular Value Decomposition(SVD)in the so-called DCT-SVD *** addition,image encryption is implemented based on chaos and DNA *** encrypted watermarked images are then transmitted through the wireless SC-fDMA *** linearMinimumMean Square Error(MMSE)equalizer is investigated in this paper to mitigate the effect of channel fading and noise on the transmitted *** subcarrier mapping schemes,namely localized and interleaved schemes,are compared in this *** study depends on different channelmodels,namely PedestrianAandVehicularA,with a modulation technique namedQuadratureAmplitude Modulation(QAM).Extensive simulation experiments are conducted and introduced in this paper for efficient transmission of encrypted watermarked *** addition,different variants of SC-fDMA bas

关键词： Cybersecurity applications image transmission channel models modulation techniques watermarking and encryption

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Cognition on oxidation behavior of Ni-based superalloy GH4742 when exposed to water vapor

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Journal of Materials Science & Technology 2024年第7期174卷 15-22页

作者： H.Xu S.f.Yang E.H.Wang C.Y.Guo Y.S.Liu X.M.Hou Y.L.Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China

The oxidation behavior of Ni-based superalloy GH4742 exposed to water vapor was investigated at 900-1100℃for 50 h in Ar+20%H_(2)O,with Ar+20%O_(2)included for *** presence of H_(2)O is adverse to formation of continuous Cr_(2)O_(3)oxide layer but contributes to generation of big *** on this,Ni^(2+)and Co^(2+)are more easily to diffuse towards the outermost oxide layer(OOL),forming non-protective Ni-and Co-rich oxides with high *** leads to a higher weight gain in Ar+20%H_(2)O than that in Ar+20%O_(2).At elevated temperatures,the spallation of oxide scale occurs while the consumption of Cr is reduced in Ar+20%H_(2)O,and the contents of Ni-and Co-rich oxides at this moment are reduced in the *** oxidation mechanism was also discussed.

关键词： GH4742 Superalloy H_(2)O Diffusion Oxidation Mechanism

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