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Boson star superradiance

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Science China(Physics,mechanics & Astronomy) 2024年第6期67卷 69-78页

作者： he-Yu Gao Paul m.Saffin Yi-Jie Wang Qi-Xin Xie Shuang-Yong Zhou School of Physical Sciences University of Science and Technology of ChinaHefei 230026China School of Physics and Astronomy University of NottinghamUniversity ParkNottingham NG72RDUK Interdisciplinary Center for Theoretical Study University of Science and Technology of ChinaHefei 230026China Peng Huanwu Center for Fundamental Theory Hefei 230026China

Recently,it has been realized that in some systems internal space rotation can induce energy amplification for scattered waves,similar to rotation in real *** particularly,it has been shown that energy extraction is possible for a Q-ball,a stationary non-topological soliton that is coherently rotating in its field *** this paper,we generalize the analysis to the case of boson stars,and show that the same energy extraction mechanism still works for boson stars.

关键词： superradiance boson star field space rotation

Bacterial community network complexity and role of stochasticity decrease during primary succession

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Soil Ecology Letters 2024年第3期6卷 45-59页

作者： Yucheng he Binu m.Tripathi Jie Fang Zihao Liu Yaping Guo Yue Xue Jonathan m.Adams School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Korea Polar Research Institute Incheon 21990Republic of Korea

In microbial ecology,there is limited understanding of the mechanisms governing patterns in community structure across space and ***,we studied the changes of bacterial co-occurrence network structure over four primary successional soils after glacier retreat,including a sand dune system and three glacier foreland series,varying in timescale from centuries to *** found that in all series,network structure was most complex in the earliest stages of succession,and became simpler over *** and abundance of keystone species and network stability also declined over *** appears that with less productive,nutrient poor and physiologically extreme conditions of early succession,closer interactions among bacterial species are ecologically selected *** may take the form of consortia(with positive interactions)or stronger niche exclusion(with negative interactions).Additionally,we quantified the relative roles of different structuring processes on bacterial community using a bin-based null model analysis(iCAmP).With each successional series,community composition was initially governed by stochasticity,but as succession proceeded there was a progressive increase in deterministic selection over time,correlated with decreasing ***,our results show a consistency among the four series in long-term processes of community succession,with more integrated networks and greater stochasticity in early stages.

关键词： glacial retreat bacteria chronosequence co-occurrence network 16S rRNA sequencing community assembly

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

CONSTANS alters the circadian clock in Arabidopsis thaliana

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molecular Plant 2024年第8期17卷 1204-1220页

作者： Pedro de los Reyes Gloria Serrano-Bueno Francisco J.Romero-Campero he Gao Jose m.Romero Federico Valverde Plant Development Group-Institute for Plant Biochemistry and Photosynthesis Consejo Superior de Investigaciones CientificasUniversidad de SevillaSevilleSpain Department of Computer Science and Artificial Intelligence Universidad de SevillaSevilleSpain Department of Plant Developmental Biology Max Planck Institute for Plant Breeding ResearchCologneGermany Department of Plant Biochemistry and molecular Biology Universidad de SevillaSevilleSpain

Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the *** these processes,the floral transition is essential to ensure reproductive success and is finelyregulated by several internal andexternal genetic *** photoperiodic pathway,which controls plant response to day length,is one of the most important pathways controlling *** Arabidopsis photoperiodic flowering,CONSTANS(CO)is the central gene activating the expression of the florigen FLOWERING LOCUS T(FT)in the leaves at the end of a long *** circadian clock strongly regulates Co ***,to date,no evidence has been reported regarding a feedbackloop from the photoperiod pathway back to the circadian *** transcriptional networks,we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod *** expression,chromatin immunoprecipitation experiments,and phenotypic analysis allowed us to elucidate the role of Co over the circadian *** with altered cO expression showed a different internal clock period,measured by daily leaf rhythmic *** showed that co upregulates the expression of key genes related to the circadian clock,such as CCA1,LHY,PRR5,and Gl,at the end of a long day by bindingto specific sites on their ***,a high numberof PRR5-repressed target genes are upregulated by CO,and this could explain the phase transition promoted by *** CO-PRR5 complex interacts with the bZiP transcriptionfactor HY5andhelps to localize the complex in the promoters of clock *** together,our results indicate that there may be a feedback loop in which co communicates back to the circadian clock,providing seasonal information to the circadian system.

关键词： CONSTANS circadian clock photoperiod

Co-doped Ni_(3)S_(2) nanosheet array: A high-efficiency electrocatalyst for alkaline seawater oxidation

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Nano Research 2024年第3期17卷 1050-1055页

作者： meng Yue Xun he Shengjun Sun Yuntong Sun mohamed S.Hamdy mhamed Benaissa Alsamani A.m.Salih Jun Liu Xuping Sun College of Chemistry Chemical Engineering and Materials ScienceShandong Normal UniversityJinan 250014China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Department of Chemistry College of ScienceKing Khalid UniversityP.O.Box 9004Abha 61413Saudi Arabia Department of Chemical Engineering College of EngineeringUniversity of Ha’ilP.O.Box 2440Ha’il 81441Saudi Arabia Department of Otolaryngology-head&Neck Surgery West China HospitalSichuan UniversityChengdu 610041China

Developing efficient and durable oxygen evolution reaction(OER)catalysts holds great promise for green hydrogen production via seawater electrolysis,but remains a ***,we report a Co-doped Ni_(3)S_(2) nanosheet array on Ni foam(Co-Ni_(3)S_(2)/NF)as a high-efficiency OER electrocatalyst for *** alkaline conditions,Co-Ni_(3)S_(2)/NF requires an overpotential of only 368 mV to drive 100 mA·cm^(–2),superior to Ni_(3)S_(2)/NF(385 mV).Besides,it exhibits at least 50-h continuous electrolysis.

关键词： Co doping Ni_(3)S_(2)nanosheet array oxygen evolution reaction seawater electrolysis electrocatalyst

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVARI m.R.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m.FEIZABAD m.H.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** Hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

Impact of COVID-19-related lifestyle changes on diabetic macular edema

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 97-106页

作者： Bryce P.Johnson Yu-Guang he Zachary m.Robertson Angeline Wang Rafael L.Ufret-Vincenty Department of Ophthalmology UT Southwestern Medical CenterDallasTexas 75390-9057USA

AIm:To assess diabetic macular edema(DmE)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office ***:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DmE seen on 3 separate visits between January 2019 and July *** 1 was January 2019 to February 2020(considered pre-COVID-19),period 2 was march 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).main outcome measures included visual acuity,body mass index(BmI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DmE treatment(s)received at each *** facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OCT ***:There was no change of BmI,systolic BP,and diastolic BP between any of the time ***1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).macular thickness decreased for 100%of macular *** central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BmI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in ***:DmE doesn’t worsen during the COVID-19 pandemic,instead sustaining a very small but statistically significant *** identifying a mechanism behind our findings is beyond the scope of this study,potential explanat

关键词： COVID-19 diabetic macular edema diabetic retinopathy optical coherence tomography