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Constraints on the primordial curvature power spectrum by pulsar timing array data:a polynomial parameterization approach

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Communications in Theoretical Physics 2024年第1期76卷 96-104页

作者： qin fei School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China

The recent stochastic signal observed jointly by NANOGrav,parkes pulsar timing array,European pulsar timing array,and Chinese pulsar timing array can be accounted for by scalarinduced gravitational waves(SIGWs).The source of the SIGWs is from the primordial curvature perturbations,and the main contribution to the SIGWs is from the peak of the primordial curvature power *** effectively model this peak,we apply the Taylor expansion to parameterize *** the Taylor expansion parameterization,we apply Bayesian methods to constrain the primordial curvature power spectrum based on the NANOGrav 15 year data *** constraint on the primordial curvature power spectrum possesses a degree of generality,as the Taylor expansion can effectively approximate a wide range of function profiles.

关键词： pulsar timing array scalar-induced gravitational waves inflation

Breaking the diffraction limit in far field by planar metalens

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Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 86-87页

作者： fei qin MingHui Hong Institute of Photonics Technology Jinan University Department of Electrical and Computer Engineering National University of Singapore

Optical lens is of fundamental importance in both scientific researches and industrial communities, especially for the aspects of optical focusing and imaging. In traditional optics, the light modulation property is limited by the Rayleigh Criterion （0.6 λ/NA）, and therefore the development of an ideal lens that produces sub-diffraction limit focusing and imaging has been a dream of lens makers all the time. Intensive effort has been made to break this barrier for centuries, however, all the reported techniques suffer from certain limitations for general applications, such as near-field operation, small field of view, or object dyeing which works only for a narrow-class of samples [1-3].

关键词： focusing Rayleigh Criterion optics planar dream communities

Test of the Brans-Dicke theory with GW200105 and GW200115

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Communications in Theoretical Physics 2024年第7期76卷 83-93页

作者： qin fei Yingjie Yang Department of Mathematics and Physics School of Biomedical EngineeringSouthern Medical UniversityGuangzhou 510515China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China

We study whether it is possible to constrain the Brans-Dicke(BD)theory from the measurement of gravitational waves(GW)released in neutron star-black hole *** the scalar field modifications through monopole and dipole radiations,we find additional contributions to the phase evolution in the emitted gravitational *** effectively calculating such effect in the post-Newtonian order,we are in a position to measure the scalar field and give bounds on the BD coupling parameterω_(BD).We derive the analytical expression for the phase modification due to the orbital eccentricity of eccentric binaries in both general relativity and BD *** the Bayesian analysis,we obtain the constraints on ω_(BD) from the GW events,GW200105 and GW200115.

关键词： cosmology Brans-Dicke theory gravitational wave

Perturbed magnetic field of an infinite plate with a centered crack

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Acta Mechanica Sinica 2011年第2期27卷 259-265页

作者： fei qin Yang Zhang Ya-Nan Liu College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology 100124 Beijing China

Deforming a cracked magnetoelastic body in a magnetic field induces a perturbed magnetic field around the crack. The quantitative relationship between this perturbed field and the stress around the crack is crucial in developing a new generation of magnetism-based nondestructive testing technologies. In this paper, an analytical expression of the perturbed magnetic field induced by structural deforma- tion of an infinite ferromagnetic elastic plate containing a centered crack in a weak external magnetic field is obtained by using the linearized magnetoelastic theory and Fourier transform methods. The main finding is that the perturbed magnetic field intensity is proportional to the applied tensile stress, and is dominated by the displacement gradient on the boundary of the magnetoelastic solid. The tangential component of the perturbed magnetic-field intensity near the crack exhibits an antisymmetric distribution along the crack that reverses its direction sharply across its two faces, while the normal component shows a symmetric distribution along the crack with singular points at the crack tips.

关键词： Magnetoelasticity Crack Perturbed magnetic field Fourier transform method Nondestructive testing

Microbial and hydrodynamic properties of aerobic granules in a sequencing batch reactor treating landfill leachate

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第3期13卷 219-229页

作者： Yan-jie WEI Min JI Guo-yi LI fei-fei qin Key Laboratory of Environmental Protection in Water Transport Engineering Ministry of Communications Tianjin Research Institute of Water Transport Engineering Tian/in 300456 China School of Environmental Science and Engineering Tianjin University Tianjin 300072 China Tianjin Tanggu Sino French Water Supply Co. Ltd Tianjin 300450 China

A sequencing batch reactor （SBR） seeded with activated sludge was established for landfill leachate treatment. Small bio-aggregates began to appear after 40-d operation, and gradually changed to mature aerobic granules, with a mean size of 0.36-0.60 ram. Their sludge volume index at 5 min （SVI5 rain）, mixed liquor volatile suspended solids （MLVSS）, and wet density were around 35 ml/g, 3.4 g/L, and 1.062 g/cm3, respectively. The settling velocities of the granules in distilled water ranged from 0.3 to 1.3 cm/s, which were faster than those in landfill leachate with a salt content of 1.4% （w/v）, and also slightly faster than those predicted by Stokes＇ law for porous but impermeable particles. Microbial community evolution during the granulation process and stages under different nitrogen loading rates （NLRs） were monitored and analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE）, cloning, and sequencing of 16S ribosomal RNA （rRNA） fragments. Results revealed that some primary and dominant communities in inoculating activated sludge died out gradually; while a few common bacteria, inhabiting soils, municipal wastewater, or activated sludge systems, dominated in the SBR system throughout. In addition, some other dominant species, associated with the aerobic granulation process, were thought to play a significant role in the formation and growth of aerobic granular sludge. During the stable operation time under low NLR, a few species were present in abundance, and may have been responsible for the high organic removal efficiency at this time.

关键词： Aerobic granules Microbial community Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE),Landfill leachate

Effect of Iron on the Stability of Rhodochrosite at the Topmost Lower Mantle Conditions

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Journal of Earth Science 2024年第2期35卷 504-513页

作者： Tianlei Zhai fei qin Shengxuan Huang Shan qin Yu Gong Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of EducationSchool of Earth and Space SciencesPeking UniversityBeijing100871China School of Earth Sciences and Resources China University of GeosciencesBeijing100083China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China

Carbonates are viewed as the principal oxidized carbon carriers during subduction,and thus the stability of subducted carbonates has significant implications for the deep carbon *** we investigate the high pressure-temperature behaviors of rhodochrosite in the presence of iron up to∼34 GPa by in-situ X-ray diffraction and ex-situ Raman *** relatively low temperature below∼1500 K,MnCO_(3)breaks down into MnO and CO_(2).Upon heating to∼1800 K,however,the MnCO_(3)-Fe^(0)reactions occur with the formation of Mn_(3)O_(4),Fe^(O)and reduced carbon.A'three-stage'reaction mechanism is proposed to understand the kinetics of the carbon-iron-manganese redox *** results suggest that Fe^(0)can serve as a reductant to greatly affect the stability of rhodochrosite,which implies that the effect of Fe-metal should be seriously considered for the high pressure-temperature behaviors of other predominant carbonates at Earth's mantle conditions,particularly at depths greater than∼250 km.

关键词： deep carbon cycle rhodochrosite reduced mantle diamond formation high pressure tectonics geochemistry

Synthesis and Characterization of Novel Sulfonylurea Derivatives

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Chemical Research in Chinese Universities 2005年第4期21卷 439-443页

作者： ZHANGGuang-liang LIYao-xian ZHANGSuo-qin GAOfei-fei CollegeofChemistry JilinUniversityChangchun130021P.R.China

On the basis of study on the mechanism of action of sulfonylurea herbicides, nine sulfonylurea derivatives of iso-{xazolidinone} were designed and synthesized. The structures of these compounds were confirmed by means of IR, MS, NMR and elemental analysis. The results of preliminary active tests indicate that the compounds have some herbicidal activity. The structure-activity relationship was also studied.

关键词： 4,4-Dimethyl-3-isoxazolidinone Sulfonylurea Acetohydroxyacid synthase Herbicidal activity

Transcriptomic Profiling of the Immune Response to Crowding Stress in Juvenile Turbot (Scophthalmus maximus)

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Journal of Ocean University of China 2020年第4期19卷 911-922页

作者： HUO Huanhuan GAO Xiaoqiang fei Fan qin fei HUANG Bin LIU Baoliang Key Laboratory of Sustainable Development of Marine Fisheries of Ministry of Agriculture Yellow Sea Fisheries Research InstituteChinese Academy of Fishery SciencesQingdao 266071China Laboratory for Marine Fisheries Science and Food Production Processes Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China College of Animal Science and Technology Jiangxi Agricultural UniversityNanchang 330045China

In this study,juvenile turbot Scophthalmus maximus were vaccinated with attenuated Edwardsiella tarda(EIBAV1)and reared at two different densities,low density(LD),(5.25±0.02)kg m−2,as control group and high density(HD),(20.53±0.05)kg m−2,as experimental *** density was considered as the *** weeks after vaccination,the transcriptomes of spleen and head kidney from the turbot in two groups were analyzed with RNA-Seq technology.A total of 447 million reads were assembled into 41136 genes with an average length of 1274 bp and a N50 size of 2295 bp.A comparison of gene expression between HD and LD groups revealed 1155 differentially expressed genes(DEGs).Enrichment and pathway analysis of the 10 immune-related DEGs showed the centrality of toll-like receptor signaling pathway,cytosolic DNA-sensing pathway and platelet activation in the host immune *** 5 overexpressed inflammatory cytokines and 5 downregulated signal-regulated cytokines genes are covered by these immune-related *** was inferred that cells suffer damage and the immune response is restrained in turbot under crowding stress.

关键词： turbot transcriptome crowding stress immune response

Experiment Investigation and Control Strategies on Two-Phase Refrigerant Injection Heat Pump System for Electric Vehicle in Start-up Stage

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Journal of Thermal Science 2021年第3期30卷 828-839页

作者： qin fei LIU Hanzhou ZOU Huiming CHEN Deqi TIAN Changqing Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of EducationChongqing UniversityChongqing 400044China Beijing Key Laboratory of Thermal Science and Technology and Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China

Due to the poor heating performance and operating safety in low ambient temperature,traditional Air Source Heat Pump(ASHP)for Electric Vehicles(EVs)has many limits in cold region,which can be solved by the ASHP with refrigerant *** the start-up stage of EV in winter,the inlet air temperature of the in-car condenser is the same as the ambient *** this situation,the performance and control strategy of the heat pump require special *** the present study,a series of experiments were carried out on the heating performance of the Refrigerant Injection Heat Pump(RIHP)system in start-up stage of EV,at the ambient temperature from–20℃ to–5℃.The effects of compressor speed and injected refrigerant state on the heating performance of the system were discussed in *** to the results,the control strategies during start-up stage have been discussed in the end of the *** study provides a practical control strategy for the RIHP system during the start-up stage of electric vehicles,helping to efficiently operate electric vehicles in cold regions.

关键词： refrigerant injection heat pump system heating performance electric vehicle start-up stage control optimization